CN120215001A

CN120215001A - Optical laminate, method for producing liquid crystal cured film, and method for producing optical laminate

Info

Publication number: CN120215001A
Application number: CN202411897861.4A
Authority: CN
Inventors: 田中贵景
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2023-12-25
Filing date: 2024-12-23
Publication date: 2025-06-27
Also published as: JP2025101406A; KR20250099627A

Abstract

The present invention provides an optical laminate having high heat resistance. The optical laminate comprises, in order, a protective film, a polarizing plate, a base film, and a liquid crystal cured film having a thickness of 2.5 [ mu ] m or more, wherein the liquid crystal cured film has an extractive liquid chromatography measurement result satisfying the following formula (A). (S/M)/(S _T/M_T). Ltoreq.6.4.. A. S: the sum of peak areas of the respective liquid crystal monomers M: the extraction solution concentration S _T: the peak area of toluene M _T: the toluene solution concentration.

Description

Optical laminate, method for producing liquid crystal cured film, and method for producing optical laminate

Technical Field

The invention relates to an optical laminate, a method for producing a liquid crystal cured film, and a method for producing an optical laminate.

Background

The circularly polarizing plate is an optical member formed by laminating a polarizing plate and a retardation plate, and is used for preventing reflection of light at electrodes constituting an organic EL image display device or the like in a device for displaying an image in a planar state. As a retardation plate constituting the circularly polarizing plate, a retardation plate using a liquid crystal cured film produced by coating a polymerizable liquid crystal compound on a substrate and curing the compound is known (see patent document 1).

Prior art literature

Patent literature

Patent document 1 Japanese patent application laid-open No. 2022-44293

Disclosure of Invention

Problems to be solved by the invention

In an optical laminate such as a circularly polarizing plate, a liquid crystal cured film is required to have high heat resistance. If the heat resistance of the liquid crystal cured film is low, there is a problem that the in-plane retardation of the liquid crystal cured film changes due to heat and the reflectance increases.

Accordingly, an object of the present invention is to provide an optical laminate having high heat resistance and a method for producing the same. The present invention also aims to provide a method for producing a liquid crystal cured film, which can give a liquid crystal cured film having high heat resistance.

Means for solving the problems

In order to solve the above problems, the present invention provides the following optical laminate, a method for producing a liquid crystal cured film, and a method for producing an optical laminate.

[1] An optical laminate comprising, in order, a protective film, a polarizing plate, a base film, and a liquid crystal cured film, wherein the thickness of the liquid crystal cured film is 2.5 [ mu ] m or more, and wherein the liquid crystal cured film satisfies the following formula (A) as a result of measurement by liquid chromatography.

(S/M)/(S_T/M_T)≤6.4 ...(A)

S total of peak areas of the liquid crystal monomers

M concentration of extraction solution

S _T peak area of toluene

M _T toluene solution concentration

[2] The optical laminate according to item [1], wherein the protective film has a 380nm transmittance of 10% or less.

[3] The optical laminate according to [1] or [2], wherein the substrate film has a 380nm transmittance of 50% or more.

[4] The optical laminate according to any one of the above [1] to [3], wherein the substrate film has a moisture permeability of 50g/m ².24 hr or more.

[5] The optical laminate according to any one of the above [1] to [4], wherein the thickness of the base film is 30 μm or more.

[6] The optical laminate according to any one of the above [1] to [5], wherein the visibility-modifying monomer transmittance Ty of the polarizing plate is 40% or more.

[7] The optical laminate according to any one of the above [1] to [6], wherein the total thickness of the optical laminate is 150 μm or less and the thickness of the polarizing plate is 15 μm or less.

[8] The optical laminate according to any one of the above [1] to [7], wherein the thickness of the cured liquid crystal film is 3.5 μm or less.

[9] A method for producing a liquid crystal cured film, comprising:

A step of forming a coating film on a base film using a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound, and

And (c) a step of forming a liquid crystal cured film having a thickness of 2.5 μm or more and satisfying the following formula (a) as a result of measurement by liquid chromatography by irradiating the film with active energy rays from both sides of the film and curing the film.

(S/M)/(S_T/M_T)≤6.4 ...(A)

S total of peak areas of the liquid crystal monomers

M concentration of extraction solution

S _T peak area of toluene

M _T toluene solution concentration

[10] The method for producing a cured liquid crystal film according to [9] above, wherein the substrate film has a 380nm transmittance of 50% or more.

[11] The method for producing a cured liquid crystal film according to [9] or [10], wherein the substrate film has a moisture permeability of 50g/m ².24 hr or more.

[12] The method for producing a cured liquid crystal film according to any one of the above [9] to [11], wherein the thickness of the base film is 30 μm or more.

[13] The method for producing a cured liquid crystal film according to any one of the above [9] to [12], wherein the cured liquid crystal film has a thickness of 3.5 μm or less.

[14] A method for producing an optical laminate comprising a protective film, a polarizing plate, a base film and a liquid crystal cured film in this order, wherein the method comprises the step of producing the liquid crystal cured film by the method for producing a liquid crystal cured film according to any one of the above items [9] to [13 ].

[15] The method for producing an optical laminate according to item [14], wherein the protective film has a 380nm transmittance of 10% or less.

[16] The method for producing an optical laminate according to [14] or [15], wherein the visibility-modifying monomer transmittance Ty of the polarizing plate is 40% or more.

[17] The method for producing an optical laminate according to any one of [14] to [16], wherein the total thickness of the optical laminate is 150 μm or less and the thickness of the polarizing plate is 15 μm or less.

Effects of the invention

According to the present invention, an optical laminate having high heat resistance and a method for producing the same can be provided. Further, according to the present invention, a method for producing a liquid crystal cured film which can give a liquid crystal cured film having high heat resistance can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing an example of an optical laminate of the present invention.

Detailed Description

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and overlapping description is omitted. The dimensional ratios in the drawings are not limited to the ratios shown in the drawings.

[ Optical laminate ]

The optical laminate of the present invention comprises, in order, a protective film, a polarizing plate, a base film, and a liquid crystal cured film, wherein the thickness of the liquid crystal cured film is 2.5 [ mu ] m or more, and the liquid crystal cured film satisfies the following formula (A) as a result of measurement by liquid chromatography.

(S/M)/(S_T/M_T)≤6.4 ...(A)

S total of peak areas of the liquid crystal monomers

M concentration of extraction solution

S _T peak area of toluene

M _T toluene solution concentration

According to the optical laminate, the thickness of the liquid crystal cured film is 2.5 μm or more, and the value of (S/M)/(S _T/M_T) of the liquid crystal cured film is 6.4 or less, whereby the optical laminate can have high heat resistance. The reason for the effect is not necessarily clear, but the inventors speculated that if the value of (S/M)/(S _T/M_T) is small, the amount of residual liquid crystal monomer is small, and therefore, even under the environment where heat is applied, the residual monomer is not easily transferred to other layers such as an adhesive layer, and as a result, heat resistance is improved. In addition, according to the optical laminate, the optical laminate can have high bending resistance and can suppress occurrence of interference unevenness.

Fig. 1 shows a schematic cross-sectional view of an optical stack according to an embodiment of the present invention. The optical laminate 100 shown in fig. 1 includes, in order, an adhesive layer 1, a liquid crystal cured film 2, an alignment film 3, a base film 4, an adhesive layer 5, a polarizing plate 6, an adhesive layer 7, and a protective film 8. In the optical laminate 100, a retardation film 10 is formed from a liquid crystal cured film 2, an alignment film 3, and a base film 4. The optical laminate 100 of the present embodiment including the retardation film 10 and the polarizing plate 6 may be a circular polarizing plate. In addition, a separator may be provided on the surface of the adhesive layer 1 opposite to the liquid crystal cured film 2. The layers constituting the optical laminate 100 will be described below.

< Adhesive layer 1>

The pressure-sensitive adhesive layer is suitable for use in bonding an optical laminate to another adherend. The adhesive layer may be a pressure-sensitive adhesive layer or an adhesive layer.

The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer is not particularly limited, and a pressure-sensitive adhesive composition having excellent optical transparency, which has been known in the related art, for example, a pressure-sensitive adhesive composition having a base polymer such as a (meth) acrylic resin, a urethane resin, a silicone resin, or a polyvinyl ether resin, may be used. The adhesive composition may be an active energy ray-curable adhesive composition, a thermosetting adhesive composition, or the like. Among them, an adhesive composition based on a (meth) acrylic resin excellent in transparency, adhesion, re-peelability, weather resistance, heat resistance and the like is suitable. The adhesive composition may further comprise a crosslinking agent, a silane compound, an antistatic agent, and the like.

((Meth) acrylic resin)

The (meth) acrylic resin contained in the adhesive composition is preferably a polymer (hereinafter, also referred to as "(meth) acrylate polymer") containing a structural unit derived from an alkyl (meth) acrylate represented by the following formula (I) (hereinafter, also referred to as "structural unit (I)") as a main component (for example, 50 parts by mass or more per 100 parts by mass of the structural unit of the (meth) acrylic resin). In the present specification, (meth) acrylic resin means "(meth)" which may be any of acrylic resin and methacrylic resin, and "(meth)" such as (meth) acrylate is also defined in the same manner.

[ Chemical formula 1]

[ Wherein R ¹⁰ represents a hydrogen atom or a methyl group, R ²⁰ represents an alkyl group having 1 to 20 carbon atoms, the alkyl group may have any of a linear, branched or cyclic structure, and the hydrogen atom of the alkyl group may be substituted with an alkoxy group having 1 to 10 carbon atoms. ]

Examples of the (meth) acrylic acid ester represented by the formula (I) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, isohexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, stearyl (meth) acrylate, and t-butyl (meth) acrylate. Specific examples of the alkyl acrylate containing an alkoxy group include 2-methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, and the like. Among them, n-butyl (meth) acrylate or 2-ethylhexyl (meth) acrylate is preferably contained, and n-butyl (meth) acrylate is particularly preferably contained.

The (meth) acrylate polymer may contain structural units derived from other monomers other than the structural unit (I). The number of structural units derived from other monomers may be 1 or 2 or more. Examples of the other monomer that may be contained in the (meth) acrylate polymer include a monomer having a polar functional group, a monomer having an aromatic group, and an acrylamide monomer.

Examples of the monomer having a polar functional group include (meth) acrylic esters having a polar functional group. Examples of the polar functional group include a hydroxyl group, a carboxyl group, a substituted amino group or an unsubstituted amino group substituted with an alkyl group having 1 to 6 carbon atoms, and a heterocyclic group such as an epoxy group.

The content of the structural unit derived from the monomer having a polar functional group in the (meth) acrylate polymer is preferably 10 parts by mass or less, more preferably 0.5 parts by mass or more and 10 parts by mass or less, still more preferably 0.5 parts by mass or more and 5 parts by mass or less, particularly preferably 1 part by mass or more and 5 parts by mass or less, per 100 parts by mass of the total structural units of the (meth) acrylate polymer.

Examples of the monomer having an aromatic group include (meth) acrylic esters each having 1 (meth) acryloyl group and 1 or more aromatic rings (for example, benzene ring, naphthalene ring, etc.) in the molecule and having a phenyl group, phenoxyethyl group, or benzyl group. By including these structural units, the whitening phenomenon of the polarizing plate generated in a high-temperature and high-humidity environment can be suppressed.

The content of the structural unit derived from the monomer having an aromatic group in the (meth) acrylate polymer is preferably 20 parts by mass or less, more preferably 4 parts by mass or more and 20 parts by mass or less, and still more preferably 4 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the total structural units of the (meth) acrylate polymer.

Examples of the acrylamide monomer include N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (butoxymethyl) acrylamide, and N- (2-methylpropoxymethyl) acrylamide. By including these structural units, bleeding of additives such as an antistatic agent described later can be suppressed.

The structural unit derived from a monomer other than the structural unit (I) may include a structural unit derived from a styrene monomer, a structural unit derived from a vinyl monomer, a structural unit derived from a monomer having a plurality of (meth) acryloyl groups in the molecule, and the like.

The weight average molecular weight (hereinafter also simply referred to as "Mw") of the (meth) acrylic resin (1) is preferably 50 to 250 ten thousand. When the weight average molecular weight is 50 ten thousand or more, the durability of the pressure-sensitive adhesive layer in a high-temperature and high-humidity environment can be improved. When the weight average molecular weight is 250 ten thousand or less, the workability in applying the coating liquid containing the adhesive composition becomes good. The molecular weight distribution (Mw/Mn), which is represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (hereinafter also simply referred to as "Mn"), is usually 2 to 10. In the present specification, the "weight average molecular weight" and the "number average molecular weight" are polystyrene equivalent values measured by a Gel Permeation Chromatography (GPC) method.

When the (meth) acrylic resin is dissolved in ethyl acetate to prepare a solution having a concentration of 20 mass%, the viscosity at 25 ℃ is preferably 20pa·s or less, more preferably 0.1 to 15pa·s. If the viscosity of the (meth) acrylic resin at 25℃is within the above range, the durability and reworkability of the polarizing plate including the adhesive layer formed of the above resin are improved. The above viscosity can be measured by a Brookfield viscometer.

The glass transition temperature (Tg) of the (meth) acrylic resin is, for example, -60 to 20 ℃, preferably, -50 to 15 ℃, more preferably, -45 to 10 ℃, still more preferably, -40 to 0 ℃. The glass transition temperature may be measured by a Differential Scanning Calorimeter (DSC).

The (meth) acrylic resin may contain 2 or more (meth) acrylate polymers. Examples of such a (meth) acrylate polymer include (meth) acrylate polymers having a relatively low molecular weight, such as a structural unit (I) derived from the above-mentioned (meth) acrylate as a main component and a weight average molecular weight in the range of 5 to 30 ten thousand.

The (meth) acrylic resin can be generally produced by a known polymerization method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method. In the production of (meth) acrylic resins, polymerization is generally carried out in the presence of a polymerization initiator. The amount of the polymerization initiator used is usually 0.001 to 5 parts by mass per 100 parts by mass of the total of all the monomers constituting the (meth) acrylic resin. The (meth) acrylic resin can also be produced by a method of polymerization using active energy rays such as ultraviolet rays.

(Crosslinking agent)

The adhesive composition preferably comprises a cross-linking agent. Examples of the crosslinking agent include conventional crosslinking agents (for example, isocyanate compounds, epoxy compounds, aziridine compounds, metal chelate compounds, peroxides, and the like), and isocyanate compounds are preferable from the viewpoints of pot life of the adhesive composition, crosslinking speed, durability of the polarizing plate, and the like.

The isocyanate compound is a compound having at least 2 isocyanate groups (-NCO) in the molecule. Specifically, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate and the like can be mentioned. Further, adducts obtained by reacting these isocyanate compounds with a polyol such as glycerin or trimethylolpropane, dimers and trimers of these isocyanate compounds are also mentioned. More than 2 isocyanate compounds may be combined.

The proportion of the crosslinking agent is, for example, 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the (meth) acrylic resin.

(Silane Compound)

The adhesive composition may further contain a silane compound.

As the silane compound, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl ethoxydimethylsilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane and the like can be mentioned. In addition, the silane compound may contain an oligomer derived from the above silane compound.

The content of the silane compound in the adhesive composition is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, per 100 parts by mass of the (meth) acrylic resin. If the content of the silane compound is 0.01 parts by mass or more, the adhesion between the adhesive layer and the adherend tends to be improved, and if the content is 10 parts by mass or less, bleeding of the silane compound from the adhesive layer tends to be suppressed.

(Antistatic agent)

The adhesive composition may further comprise an antistatic agent. As the antistatic agent, known antistatic agents are mentioned, and ionic antistatic agents are suitable. Examples of the cationic component constituting the ionic antistatic agent include organic cations and inorganic cations. Examples of the organic cation include pyridinium cation, imidazolium cation, ammonium cation, sulfonium cation, and phosphonium cation. Examples of the inorganic cations include alkali metal cations such as lithium cations, potassium cations, sodium cations, cesium cations, alkaline earth metal cations such as magnesium cations, and calcium cations. The anionic component constituting the ionic antistatic agent may be any of inorganic anions and organic anions, and is preferably an anionic component containing a fluorine atom in view of excellent antistatic performance. Examples of the anionic component containing a fluorine atom include hexafluorophosphate anion (PF ₆ ^-) and bis (trifluoromethanesulfonyl) imide anion [ (CF ₃SO₂）₂N^- ], bis (fluorosulfonyl) imide anion [ (FSO ₂）₂N^- ] anion) and the like, and an ionic antistatic agent which is solid at room temperature is preferable from the viewpoint of excellent stability with time of antistatic performance of the adhesive composition.

The content of the antistatic agent is, for example, 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 1 to 7 parts by mass, based on 100 parts by mass of the (meth) acrylic resin.

The adhesive composition may contain additives such as ultraviolet absorbers, solvents, crosslinking catalysts, tackifying resins (tackifiers), plasticizers, and the like, singly or in combination of 2 or more. In addition, a method of forming an adhesive layer by mixing an ultraviolet-curable compound with an adhesive composition and then curing the adhesive layer by irradiation with ultraviolet rays to form a harder adhesive layer is also useful.

The adhesive layer can be formed, for example, by dissolving or dispersing the above-mentioned adhesive composition in a solvent to prepare an adhesive composition containing the solvent, and then applying it to the surface of the layer on which the adhesive layer is to be provided and drying it.

The thickness of the pressure-sensitive adhesive layer is usually 0.1 to 30. Mu.m, preferably 3 to 30. Mu.m, more preferably 5 to 25. Mu.m.

< Liquid Crystal cured film 2>

The liquid crystal cured film is a layer exhibiting a retardation, and is an optically anisotropic layer formed of a polymer in which a polymerizable liquid crystal compound is aligned. The liquid crystal cured film is also called a retardation film.

In terms of thickness reduction and capability of arbitrarily designing wavelength dispersion characteristics, it is preferable that a composition containing a polymerizable liquid crystal compound (hereinafter also referred to as "polymerizable liquid crystal composition") is coated on a transparent substrate to form a liquid crystal cured film made of a polymer in which the polymerizable liquid crystal compound is oriented. The polymerizable liquid crystal composition may further contain a solvent, a photopolymerization initiator, a photosensitizing agent, a polymerization inhibitor, a leveling agent, an adhesion improving agent, and the like.

The liquid crystal cured film is generally formed by applying a polymerizable liquid crystal composition to an alignment film formed on a base film described later, and polymerizing a polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition. The liquid crystal cured film may be formed by directly coating a polymerizable liquid crystal composition on a base film described later, and polymerizing a polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition. The liquid crystal cured film is generally a film in which a polymerizable liquid crystal compound is cured in an aligned state, and in order to generate a retardation in the viewing plane, it is necessary to be a cured film in which a polymerizable group is polymerized in a state in which the polymerizable liquid crystal compound is aligned in a horizontal direction with respect to the substrate surface. In this case, the positive a plate may be used when the polymerizable liquid crystal compound is a rod-like liquid crystal, and the negative a plate may be used when the polymerizable liquid crystal compound is a discotic liquid crystal.

Since the optical laminate in which the base film described later functions as a protective film for a polarizing plate does not have an adhesive layer between the protective film (base film) and the liquid crystal cured film, the flexibility is inferior to an optical laminate in which an adhesive layer serving as a buffer material is generally provided between the protective film (base film) and the liquid crystal cured film, but the flexibility can be improved according to the present invention.

In order to highly realize the antireflection function, the liquid crystal cured film may have a λ/4 plate function (i.e., a pi/2 retardation function) in the entire visible light region. Specifically, the layer may be an inverse wavelength dispersive λ/4 layer, or 2 or more kinds of liquid crystal cured films having different orientations may be combined. For example, a liquid crystal cured film having a λ/2 plate function (i.e., a phase difference function of pi) may be combined with a liquid crystal cured film having a λ/4 plate function (i.e., a phase difference function of pi/2).

Further, from the viewpoint of being able to compensate for the antireflection function in the oblique direction, a layer (positive C plate) having anisotropy in the thickness direction may be included. The respective liquid crystal cured films may be obliquely oriented, or may be in a cholesteric orientation (コ parts in Japanese) state.

Regarding the λ/4 function in the entire visible light region, if the in-plane retardation with respect to light having a wavelength of λnm is set to R (λ), the liquid crystal cured film preferably satisfies the optical characteristics shown by the following formula (a), and preferably satisfies the optical characteristics shown by the following formulas (a), b) and c).

100nm<Re(550)<160nm ...(a)

(Wherein Re (550) represents the in-plane retardation value (in-plane retardation) with respect to light having a wavelength of 550 nm.)

Re(450)/Re(550)≤1.0 ...(b)

1.00≤Re(650)/Re(550) ...(c)

(Wherein Re (450) represents an in-plane phase difference value with respect to light having a wavelength of 450nm, re (550) represents an in-plane phase difference value with respect to light having a wavelength of 550nm, re (650) represents an in-plane phase difference value with respect to light having a wavelength of 650 nm.)

If the "Re (450)/Re (550)" of the liquid crystal cured film exceeds 1.0, light leakage on the short wavelength side in the circularly polarizing plate provided with the liquid crystal cured film becomes large. The "Re (450)/Re (550)" is preferably 0.7 or more and 1.0 or less, more preferably 0.80 or more and 0.95 or less, still more preferably 0.80 or more and 0.92 or less, and particularly preferably 0.82 or more and 0.88 or less. The value of "Re (450)/Re (550)" can be arbitrarily adjusted by adjusting the mixing ratio of the polymerizable liquid crystal compound, the lamination angle of the plurality of liquid crystal cured films, and the phase difference value.

The in-plane retardation of the liquid crystal cured film can be adjusted by the thickness of the liquid crystal cured film. Since the in-plane phase difference value is determined by the following formula (d), Δn (λ) and film thickness d may be adjusted to obtain a desired in-plane phase difference value (Re (λ)). The Δn (λ) depends on the molecular structure of a polymerizable liquid crystal compound described later.

Re(λ)=d×Δn(λ) ...(d)

(Wherein Re (λ) represents the in-plane phase difference value at wavelength λnm, d represents the film thickness, and Δn (λ) represents the birefringence at wavelength λnm.)

The thickness of the liquid crystal cured film is 2.5 μm or more, preferably more than 2.5 μm, more preferably 2.6 μm or more, still more preferably 2.7 μm or more, and particularly preferably more than 3.0 μm. By setting the thickness of the liquid crystal cured film to 2.5 μm or more, the heat resistance of the optical laminate can be improved, and the occurrence of interference unevenness can be suppressed. The thickness of the liquid crystal cured film is preferably 5.0 μm or less, more preferably 4.0 μm or less, further preferably 3.8 μm or less, and particularly preferably 3.5 μm or less. By setting the thickness of the liquid crystal cured film to 5.0 μm or less, the liquid crystal cured film can be easily cured sufficiently, and heat resistance can be further improved. From the above viewpoints, the thickness of the liquid crystal cured film is preferably 2.5 to 5.0 μm, more preferably more than 2.5 μm and 4.0 μm or less, still more preferably 2.6 to 3.8 μm, particularly preferably 2.7 to 3.5 μm, and most preferably more than 3.0 μm and 3.5 μm or less. The thickness of the liquid crystal cured film can be measured by an interferometer film thickness meter, a laser microscope, or a stylus film thickness meter.

In the liquid crystal cured film extraction liquid chromatography measurement, the value of (S/M)/(S _T/M_T) is preferably 6.4 or less, more preferably 5.9 or less, and even more preferably 5.1 or less, when the total of the peak areas of the liquid crystal monomers is S, the concentration of the extraction solution is M (mg/mL), the peak area of toluene is S _T, and the concentration of the toluene solution is M _T (mg/mL). By setting the value of (S/M)/(S _T/M_T) to 6.4 or less, it is possible to suppress the change in-plane phase difference in the heat resistance test. The extraction liquid chromatography assay may be performed as follows. The peak of the liquid crystal monomer can be determined based on the peak when the liquid crystal monomer alone is used for the measurement of the extraction liquid chromatography.

The liquid crystal cured film was frozen and pulverized, and 100mg of the frozen and pulverized liquid crystal cured film was dissolved in 5mL of THF. The ultrasonic treatment was performed for 10 minutes, and an extraction solution of m=20 mg/mL was prepared by filtration through a 0.45 μm filter, and S was measured under the following measurement conditions. As the measurement sample, a liquid crystal cured film which is cured by irradiation with active energy rays for 24 hours or longer may be used. The measurement sample is not required to be a single liquid crystal cured film, and the same measurement can be performed even with a base film or a liquid crystal cured film with a polarizing plate by converting the thickness.

Measuring apparatus liquid chromatograph (trade name: LC-20A manufactured by Shimadzu corporation)

Ultraviolet visible light detector (SPD-40M) photodiode array detector manufactured by Shimadzu corporation

Column L-column ODS (3.0 mm. Phi. Times.100 mm,5 μm)

Mobile phase A ultrapure water (0.1% trifluoroacetic acid added)

Mobile phase B acetonitrile (0.1% trifluoroacetic acid added)

Gradient conditions:

mobile phase B) 70% -100% (0 min..about.15 min..about.45 min.)

The flow rate is 0.5mL/min.

Oven temperature 40 DEG C

UV detection wavelength 280nm (bandwidth: 4nm, slit width: 8 nm)

Injection amount 5. Mu.L

(Polymerizable liquid Crystal Compound)

The polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition is a liquid crystal compound having a polymerizable group, particularly a photopolymerizable group, and a conventionally known polymerizable liquid crystal compound can be used as the polymerizable liquid crystal compound. The photopolymerizable group means a group capable of participating in polymerization reaction by a reactive species generated by a photopolymerization initiator, for example, a reactive radical, an acid, or the like. Examples of the photopolymerizable group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, epoxyethyl, and oxetanyl groups. Among them, acryloyloxy, methacryloyloxy, ethyleneoxy, ethyleneoxide, and oxetanyl groups are preferable, and acryloyloxy is more preferable. The liquid crystal property may be a thermotropic liquid crystal or a lyotropic liquid crystal, and the thermotropic liquid crystal is preferable in view of being capable of controlling the film thickness in a compact state. The phase-ordered structure in the thermotropic liquid crystal may be a nematic liquid crystal or a smectic liquid crystal. The liquid crystal may be a rod-like liquid crystal or a discotic liquid crystal. The polymerizable liquid crystal compound may be used singly or in combination of two or more.

The polymerizable liquid crystal compound is preferably a liquid crystal having a mesogenic structure in a T-shape or H-shape which further has birefringence in a direction perpendicular to the molecular long axis direction from the viewpoint of exhibiting reverse wavelength dispersibility, and is more preferably a T-shape liquid crystal from the viewpoint of obtaining stronger dispersion, and specifically, for example, a compound represented by the following formula (II) is exemplified as the structure of the T-shape liquid crystal.

[ Chemical formula 2]

In the formula (II), ar represents a divalent aromatic group which may have a substituent. The divalent aromatic group preferably contains at least 1 or more of a nitrogen atom, an oxygen atom, and a sulfur atom. When the number of aromatic groups contained in the divalent group Ar is 2 or more, 2 or more aromatic groups may be bonded to each other through a divalent bonding group such as a single bond, -CO-O-, -O-.

G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. The hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and the carbon atoms constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom.

L ¹、L²、B¹ and B ² are each independently a single bond or a divalent linking group.

K. l each independently represents an integer of 0 to 3 and satisfies a relationship of 1≤k+l. Here, in the case where 2≤k+l, B ¹ and B ²、G¹ and G ² may be the same or different from each other.

E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, wherein hydrogen atoms contained in the alkanediyl group may be substituted with halogen atoms, the-CH ₂ -contained in the alkanediyl group may be replaced by-O- -substitution of S-, -COO-, -S-, -a COO-substitution, the substitution being carried out. P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom, and at least 1 is a polymerizable group.

Each of G ¹ and G ² is independently preferably a 1, 4-benzenediyl group which may be substituted with at least 1 substituent selected from a halogen atom and an alkyl group having 1 to 4 carbon atoms, a 1, 4-cyclohexanediyl group which may be substituted with at least 1 substituent selected from a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a 1, 4-benzenediyl group substituted with a methyl group, an unsubstituted 1, 4-benzenediyl group, or an unsubstituted 1, 4-trans-cyclohexanediyl group, particularly preferably an unsubstituted 1, 4-benzenediyl group, or an unsubstituted 1, 4-trans-cyclohexanediyl group.

It is preferable that at least 1 of G ¹ and G ² in the plurality of groups is a divalent alicyclic hydrocarbon group, and it is more preferable that at least 1 of G ¹ and G ² bonded to L ¹ or L ² is a divalent alicyclic hydrocarbon group.

L ¹ and L ² are each independently preferably a single bond, an alkylene group 、-O-、-S-、-R^a1OR^a2-、-R^a3COOR^a4-、-R^a5OCOR^a6-、R^a7OC=OOR^a8-、-N=N-、-CR^c=CR^d-、 having 1 to 4 carbon atoms or-C.ident.C-. Here, R ^a1～R^a8 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d each represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1-、-CH₂-、-CH₂CH₂-、-COOR^a4-1 -, OR OCOR ^a6-1 -. Here, R ^a2-1、R^a4-1、R^a6-1 each independently represents any one of a single bond, -CH ₂-、-CH₂CH₂ -. L ¹ and L ² are each independently further preferably a single bond, -O-, -CH ₂CH₂-、-COO-、-COOCH₂CH₂ -, or-OCO-.

B ¹ and B ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, a-O-, -S-, -R ^a9OR^a10-、-R^a11COOR^a12-、-R^a13OCOR^a14 -, or-R ^a15OC=OOR^a16 -. Here, R ^a9～R^a16 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms. More preferably, each of B ¹ and B ² is independently a single bond, -OR ^a10-1-、-CH₂-、-CH₂CH₂-、-COOR^a12 ^-1 -, OR-OCOR ^a14-1 -. Here, R ^a10-1、R^a12-1、R^a14-1 each independently represents any one of a single bond, -CH ₂-、-CH₂CH₂ -. B ¹ and B ² are each independently further preferably a single bond, -O-, -CH ₂CH₂-、-COO-、-COOCH₂CH₂ -, -OCO-, or-OCOCH ₂CH₂ -.

From the viewpoint of exhibiting inverse wavelength dispersibility, k and l are preferably in the range of 2≤k+l≤6, preferably k+l=4, more preferably k=2 and l=2. K=2 and l=2 are preferable because they have a symmetrical structure.

E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, more preferably an alkanediyl group having 4 to 12 carbon atoms.

Examples of the polymerizable group represented by P ¹ or P ² include an epoxy group, a vinyl group, an ethyleneoxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an ethyleneoxide group, and an oxetanyl group. Among them, acryloyloxy, methacryloyloxy, ethyleneoxy, ethyleneoxide, and oxetanyl groups are preferable, and acryloyloxy is more preferable.

Ar preferably has at least one selected from the group consisting of an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron withdrawing group. Examples of the aromatic hydrocarbon ring include benzene ring, naphthalene ring, and anthracene ring, and benzene ring and naphthalene ring are preferable. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Among them, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazolyl group is more preferable. In addition, in the case where a nitrogen atom is contained in Ar, the nitrogen atom preferably has pi electrons.

In the formula (II), the total number N _π of pi electrons contained in the 2-valent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, further preferably 14 or more, and particularly preferably 16 or more. The content is preferably 30 or less, more preferably 26 or less, and even more preferably 24 or less.

Examples of the aromatic group represented by Ar include the following groups.

[ Chemical formula 3]

In the formula (Ar-1) to (Ar-23), the marks represent a connecting portion, and Z ⁰、Z¹ and Z ² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfonyl group having 1 to 12 carbon atoms, or an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms.

Q ¹、Q² and Q ³ each independently represent-CR ^2'R^3'-、-S-、-NH-、-NR^2' -; -CO-or-O-, R ^2' and R ^3' each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

J ¹ and J ² each independently represent a carbon atom, or a nitrogen atom.

Y ¹、Y² and Y ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.

W ¹ and W ² each independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.

Examples of the aromatic hydrocarbon group in Y ¹、Y² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl, naphthyl, anthryl, phenanthryl, and biphenyl, and preferably phenyl and naphthyl, and more preferably phenyl. Examples of the aromatic heterocyclic group include an aromatic heterocyclic group having 4 to 20 carbon atoms, which contains at least 1 heteroatom such as a nitrogen atom, an oxygen atom, and a sulfur atom, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group, a thiazolyl group, and a benzothiazolyl group, and a thienyl group, a pyridyl group, a thiazolyl group, and a benzothiazolyl group are preferable.

Y ¹、Y² and Y ³ each independently may be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted. Polycyclic aromatic hydrocarbon groups refer to fused polycyclic aromatic hydrocarbon groups or groups derived from an aromatic ring set. Polycyclic aromatic heterocyclic groups refer to fused polycyclic aromatic heterocyclic groups, or groups derived from an aromatic ring set.

Z ⁰、Z¹ and Z ² are each independently preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 12 carbon atoms, Z ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, or a cyano group.

Q ¹、Q² and Q ³ are preferably-NH-, -S-, -NR ^2'-、-O-,R^2' are preferably hydrogen atoms. Wherein, the particularly preferred are-S-; -O-, -NH-.

In the formulae (Ar-1) to (Ar-23), the formulae (Ar-6) and (Ar-7) are preferable from the viewpoint of stability of the molecule.

In the formulae (Ar-16) to (Ar-23), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups which may be contained in Ar and are described above, and examples thereof include pyrrole rings, imidazole rings, pyrroline rings, pyridine rings, pyrazine rings, pyrimidine rings, indole rings, quinoline rings, isoquinoline rings, purine rings, pyrrolidine rings, and the like. The aromatic heterocyclic group may have a substituent. In addition, Y ¹ may be the above-described polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group which may be substituted together with the nitrogen atom to which it is bonded and Z ⁰. Examples thereof include a benzofuran ring, a benzothiazole ring, and a benzoxazole ring.

Among the polymerizable liquid crystal compounds, compounds having a maximum absorption wavelength of 300 to 400nm are preferable. When the photopolymerization initiator is contained in the polymerizable liquid crystal composition, there is a possibility that the polymerization reaction and gelation of the polymerizable liquid crystal compound proceed during long-term storage. However, if the maximum absorption wavelength of the polymerizable liquid crystal compound is 300 to 400nm, the generation of reactive species derived from the photopolymerization initiator and the progress of polymerization and gelation of the polymerizable liquid crystal compound due to the reactive species can be effectively suppressed even when exposed to ultraviolet light during storage. Therefore, the composition is advantageous in terms of long-term stability of the polymerizable liquid crystal composition, and the alignment property and uniformity of film thickness of the obtained liquid crystal cured film can be improved. The maximum absorption wavelength of the polymerizable liquid crystal compound can be measured in a solvent using an ultraviolet-visible spectrophotometer. The solvent is a solvent capable of dissolving the polymerizable liquid crystal compound, and examples thereof include chloroform.

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition is, for example, 70 to 99.5% by mass, preferably 80 to 99% by mass, more preferably 85 to 98% by mass, and even more preferably 90 to 95% by mass, based on 100% by mass of the total solid content of the polymerizable liquid crystal composition. If the content of the polymerizable liquid crystal compound is within the above range, it is advantageous from the viewpoint of the orientation of the obtained liquid crystal cured film. In the present specification, the solid content of the polymerizable liquid crystal composition means all components obtained by removing volatile components such as an organic solvent from the polymerizable liquid crystal composition.

The polymerizable liquid crystal composition may further contain a solvent, a leveling agent, a polymerization initiator, a photosensitizing agent, a polymerization inhibitor, a crosslinking agent, a thickener, and other reactive additives, and from the viewpoint of processability, the composition preferably contains a solvent and a leveling agent.

(Composition comprising a positive wavelength-dispersive lambda/2 layer and a positive wavelength-dispersive lambda/4 layer)

As one of methods for realizing the antireflection performance, a structure in which a positive wavelength dispersive λ/2 layer and a positive wavelength dispersive λ/4 layer are combined is known. This structure can be obtained by combining the layers having the optical characteristics represented by the formulas (e), (g) and (h) with the layers having the optical characteristics represented by the formulas (f), (g) and (h) in a specific slow axis relationship, for example.

100nm<Re(550)<160nm ...(e)

200nm<Re(550)<320nm ...(f)

Re(450)/Re(550)≥1.00 ...(g)

1.00≥Re(650)/Re(550) ...(h)

As a method of combining the above-described configurations, known methods such as japanese patent application laid-open publication No. 2015-163935 and WO2013/137464 are mentioned. From the viewpoint of viewing angle compensation, a λ/2 layer of a polymer containing a discotic polymerizable liquid crystal compound and a λ/4 layer of a polymer containing a rod-like polymerizable liquid crystal compound are preferably used.

The composition of the tilt alignment and cholesteric alignment is not particularly limited except for the composition of the positive wavelength dispersion λ/2 layer and the positive wavelength dispersion λ/4 layer, and may be any composition that realizes an antireflection function, and examples thereof include known compositions such as WO2021/060378, WO2021/132616 and WO 2021/132624.

In the structure in which the positive wavelength dispersion λ/2 layer and the positive wavelength dispersion λ/4 layer are combined, the "thickness of the liquid crystal cured film" in the present invention means the total value of the thicknesses of the positive wavelength dispersion λ/2 layer and the positive wavelength dispersion λ/4 layer. Wherein, in the case where the bonding layer is present between the positive wavelength dispersibility λ/2 layer and the positive wavelength dispersibility λ/4 layer, the thickness of the bonding layer is not included in the "thickness of the liquid crystal cured film".

Examples of the discotic polymerizable liquid crystal compound include compounds containing a group represented by the following formula (W).

[ Chemical formula 4]

In the formula (W), R ⁴⁰ each independently represents the following formulas (W-1) to (W-5). ]

[ Chemical formula 5]

X ⁴⁰ and Z ⁴⁰ represent an alkanediyl group having 1 to 12 carbon atoms, wherein the hydrogen atoms contained in the alkanediyl group are optionally substituted with an alkoxy group having 1 to 5 carbon atoms, and wherein the hydrogen atoms contained in the alkoxy group are optionally substituted with halogen atoms. In addition, in the case of the optical fiber, -CH ₂ for constructing the alkanediyl radical can be replaced by-O-or-CO-.

(Positive C plate)

The positive C plate is not particularly limited as long as it has anisotropy in the thickness direction, and has optical characteristics represented by the following formula (i) when no tilt alignment or cholesteric alignment is performed.

nx≈ny<nz ...(i)

The in-plane phase difference Re (550) of the positive C plate at the wavelength of 550nm is usually in the range of 0 to 10nm, preferably in the range of 0 to 5 nm. The phase difference Rth (550) in the thickness direction at a wavelength of 550nm is usually in the range of-170 nm to-10 nm, preferably-150 nm to-20 nm, more preferably-100 nm to-40 nm. If the phase difference value in the thickness direction is within this range, the antireflection property in the oblique direction can be further improved.

When the positive C plate is a stretched film, the thickness thereof is usually 300 μm or less, preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less. In the case where the positive C plate is a coating layer formed by polymerizing a polymerizable liquid crystal, the thickness thereof is usually 10 μm or less, preferably 5 μm or less, more preferably 0.3 μm or more and 3 μm or less. The thickness of the positive C plate is not included in the "thickness of the liquid crystal cured film" in the present invention.

The positive C plate is preferably a coating layer formed by polymerizing 1 or more polymerizable liquid crystal compounds. As the polymerizable liquid crystal compound, a rod-shaped polymerizable liquid crystal compound is preferably used.

Examples of the rod-shaped polymerizable liquid crystal compound include compounds represented by the formula (III), the formula (IV), the formula (V), the formula (VI), the formula (VII) and the formula (VIII).

P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-B16-E12-B17-P12 (III)

P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-A14-F11 (IV)

P11-B11-E11-B12-A11-B13-A12-B14-A13-B15-E12-B17-P12 (V)

P11-B11-E11-B12-A11-B13-A12-B14-A13-F11 (VI)

P11-B11-E11-B12-A11-B13-A12-B14-E12-B17-P12 (VII)

P11-B11-E11-B12-A11-B13-A12-F11 (VIII)

[ Wherein A11 represents a 2-valent alicyclic hydrocarbon group or a 2-valent aromatic hydrocarbon group. The hydrogen atoms contained in the 2-valent alicyclic hydrocarbon group and the 2-valent aromatic hydrocarbon group may be substituted with halogen atoms, alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, cyano groups or nitro groups, and the hydrogen atoms contained in the alkyl groups having 1 to 6 carbon atoms and the alkoxy groups having 1 to 6 carbon atoms may be substituted with fluorine atoms.

B11 represents-O-, -S-; -CO-O- -O-CO-, -O-CO-O-, -CO-NR ¹⁶-、-NR¹⁶ -CO-, -CS-, or a single bond. R ¹⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

B12 and B13 each independently represent -C≡C-、-CH＝CH-、-CH₂-CH₂-、-O-、-S-、-C（＝O）-、-C（＝O）-O-、-O-C（＝O）-、-O-C（＝O）-O-、-CH＝N-、-N＝CH-、-N＝N-、-C（＝O）-NR¹⁶-、-NR¹⁶-C（＝O）-、-OCH₂-、-OCF₂-、-CH₂O-、-CF₂O-、-CH＝CH-C（＝O）-O-、-O-C（＝O）-CH＝CH- or a single bond.

E11 represents an alkanediyl group having 1 to 12 carbon atoms, wherein the hydrogen atoms contained in the alkanediyl group are optionally substituted by alkoxy groups having 1 to 5 carbon atoms, and wherein the hydrogen atoms contained in the alkoxy groups are optionally substituted by halogen atoms. In addition, in the case of the optical fiber, -CH ₂ for constructing the alkanediyl radical can be replaced by-O-or-CO-. ]

The number of carbon atoms of the aromatic hydrocarbon group and the alicyclic hydrocarbon group of A11 is preferably 3 to 18, more preferably 5 to 12, and particularly preferably 5 or 6. As A11, cyclohexane-1, 4-diyl, 1, 4-phenylene is preferred.

E11 is preferably a linear alkanediyl group having 1 to 12 carbon atoms. the-CH ₂ -groups constituting the alkanediyl groups may be replaced by-O-.

Specific examples of E11 include straight-chain alkanediyl groups having 1 to 12 carbon atoms such as methylene, ethylene, propane-1, 3-diyl, butane-1, 4-diyl, pentane-1, 5-diyl, hexane-1, 6-diyl, heptane-1, 7-diyl, octane-1, 8-diyl, nonane-1, 9-diyl, decane-1, 10-diyl, undecane-1, 11-diyl and dodecane-1, 12-diyl, ;-CH₂-CH₂-O-CH₂-CH₂-、-CH₂-CH₂-O-CH₂-CH₂-O-CH₂-CH₂- and -CH₂-CH₂-O-CH₂-CH₂-O-CH₂-CH₂-O-CH₂-CH₂-.

As a result of the fact that as B11, preferably-O-, -S-; -CO-O-, -O-CO-, -and of these, -CO-O-is more preferable.

As B12 and B13, each independently, is preferably-O-, -S-, -C (=o) -O-, -O-C (=o) -O-, and, of these, more preferably-O-or-O-C (=o) -O-.

The polymerizable group represented by P11 is preferably a radical polymerizable group or a cation polymerizable group in view of high polymerization reactivity, particularly photopolymerization reactivity, and is preferably a group represented by the following formulas (P-11) to (P-15) in view of easy handling and easy production of the liquid crystal compound itself.

[ Chemical formula 6]

In the formulae (P-11) to (P-15), R ¹⁷～R²¹ each independently represents an alkyl group having 1 to 6 carbon atoms or a hydrogen atom. ]

Specific examples of the group represented by the following formula (P-11) to (P-15) include the group represented by the following formula (P-16) to (P-20).

[ Chemical formula 7]

P11 is preferably a group represented by the formula (P-14) to (P-20), more preferably a vinyl group, a P-distyryl group, an epoxy group or an oxetanyl group.

The group represented by P11-B11-is more preferably an acryloyloxy group or a methacryloyloxy group.

In the formulas (III) - (VIII), A12-A14 are respectively and independently the same as A11, B14-B16 are respectively and independently the same as B12, B17 and B11 are respectively the same as E12 and E11. F11 represents a hydrogen atom, an alkyl group having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, a cyano group, a nitro group, a trifluoromethyl group, a dimethylamino group, a hydroxyl group, a hydroxymethyl group, a formyl group, a sulfo group (-SO ₃ H), a carboxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms or a halogen atom, and-CH ₂ -constituting the alkyl group and the alkoxy group may be replaced with-O-.

(Solvent)

The polymerizable liquid crystal composition may contain a solvent. In general, since the viscosity of the polymerizable liquid crystal compound is high, the liquid crystal composition is easily applied by being prepared as a polymerizable liquid crystal composition dissolved in a solvent, and as a result, a liquid crystal cured film is easily formed in many cases. The solvent is preferably a solvent capable of completely dissolving the polymerizable liquid crystal compound, and is preferably a solvent inactive to the polymerization reaction of the polymerizable liquid crystal compound.

Examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether and propylene glycol monomethyl ether, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ -butyrolactone or propylene glycol methyl ether acetate and ethyl lactate, ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone, aliphatic hydrocarbon solvents such as pentane, hexane and heptane, aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, chlorine-containing solvents such as chloroform and chlorobenzene, amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone and 1, 3-dimethyl-2-imidazolidinone, and the like. These solvents may be used alone or in combination of 2 or more.

The content of the solvent is preferably 50 to 98 mass% relative to the total amount of the polymerizable liquid crystal composition. In other words, the content of the solid component in the polymerizable liquid crystal composition is preferably 2 to 50% by mass, more preferably 5 to 30% by mass. If the content of the solid component is 50 mass% or less, the viscosity of the polymerizable liquid crystal composition becomes low, and thus the thickness of the liquid crystal cured film becomes substantially uniform, whereby the liquid crystal cured film tends to be less likely to be uneven. The content of the solid component can be determined in consideration of the thickness of the cured liquid crystal film to be produced.

(Leveling agent)

The polymerizable liquid crystal composition may contain a leveling agent. The leveling agent is an additive having a function of adjusting the fluidity of the composition and flattening a film obtained by coating the composition, and examples thereof include organomodified silicone-based, polyacrylate-based and perfluoroalkyl-based leveling agents. Among them, the polyacrylate-based leveling agent and the perfluoroalkyl-based leveling agent are preferable when the composition is horizontally oriented, and the organomodified silicone-based leveling agent and the perfluoroalkyl-based leveling agent are preferable when the composition is vertically oriented.

When the polymerizable liquid crystal composition contains a leveling agent, the content of the leveling agent is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound. If the content of the leveling agent is within the above range, it tends to be easy to horizontally orient the polymerizable liquid crystal compound and the resulting liquid crystal cured film becomes smoother. If the content of the leveling agent with respect to the polymerizable liquid crystal compound exceeds the above range, the resulting liquid crystal cured film tends to be uneven. The polymerizable liquid crystal composition may contain 2 or more leveling agents.

(Polymerization initiator)

The polymerizable liquid crystal composition may contain a polymerization initiator. The polymerization initiator is a compound capable of initiating a polymerization reaction of a polymerizable liquid crystal compound or the like. As the polymerization initiator, a photopolymerization initiator that generates living radicals by the action of light is preferable from the standpoint of not depending on the phase state of the thermotropic liquid crystal.

The photopolymerization initiator may be any known photopolymerization initiator as long as it is a compound capable of initiating polymerization reaction of the polymerizable liquid crystal compound. Specifically, a photopolymerization initiator capable of generating a living radical or an acid by the action of light is exemplified, and among them, a photopolymerization initiator capable of generating a radical by the action of light is preferable. The photopolymerization initiator may be used alone or in combination of 2 or more.

As the photopolymerization initiator, a known photopolymerization initiator may be used, and as the photopolymerization initiator generating active radicals, for example, a self-cleaving benzoin compound, acetophenone compound, hydroxyacetophenone compound, α -aminoacetophenone compound, oxime ester compound, acylphosphine oxide compound, azo compound, etc., a hydrogen abstraction benzophenone compound, alkylbenzene ketone compound, benzoin ether compound, benzil ketal compound, dibenzocycloheptadienone (japanese: benzoquinone) compound, anthraquinone compound, xanthone compound, thioxanthone compound, halogenated acetophenone compound, dialkoxyacetophenone compound, halogenated bisimidazole compound, halogenated triazine compound, etc. may be used. As the photopolymerization initiator for generating an acid, iodonium salts, sulfonium salts, and the like can be used. From the viewpoint of excellent reaction efficiency at low temperatures, a photopolymerization initiator selected from cleavage type is preferable, and acetophenone-based compounds, hydroxyacetophenone-based compounds, α -aminoacetophenone-based compounds, and oxime ester-based compounds are particularly preferable.

The content of the polymerization initiator in the polymerizable liquid crystal composition may be appropriately adjusted according to the type and amount of the polymerizable liquid crystal compound, and is usually 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the content of the polymerizable liquid crystal compound. If the content of the polymerization initiator is within the above range, polymerization can be performed without disturbing the orientation of the polymerizable liquid crystal compound.

(Sensitizer)

The polymerizable liquid crystal composition may contain a sensitizer. As the sensitizer, a photosensitizing agent is preferable. Examples of the sensitizer include xanthone compounds such as xanthone and thioxanthone (for example, 2, 4-diethylthioxanthone and 2-isopropylthioxanthone), anthracene compounds such as anthracene and alkoxy group-containing anthracene (for example, dibutoxyanthracene), phenothiazine and rubrene.

When the polymerizable liquid crystal composition contains a sensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition can be further promoted. The sensitizer is used in an amount of preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound.

(Antioxidant)

The polymerizable liquid crystal composition may contain an antioxidant from the viewpoint of stably conducting the polymerization reaction. The degree of progress of the polymerization reaction of the polymerizable liquid crystal compound can be controlled by the antioxidant.

The antioxidant may be, for example, a primary antioxidant selected from a phenol-based antioxidant, an amine-based antioxidant, a quinone-based antioxidant and a nitroso-based antioxidant, or a secondary antioxidant selected from a phosphorus-based antioxidant and a sulfur-based antioxidant.

When the polymerizable liquid crystal composition contains an antioxidant, the content of the antioxidant is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, per 100 parts by mass of the content of the polymerizable liquid crystal compound. The antioxidant may be used alone or in combination of 2 or more. If the content of the antioxidant is within the above range, polymerization can be performed without disturbing the orientation of the polymerizable liquid crystal compound.

(Reactive additive)

The polymerizable liquid crystal composition may contain a reactive additive. The reactive additive preferably has a carbon-carbon unsaturated bond, an active hydrogen reactive group, and a mercapto group in its molecule. The "active hydrogen-reactive group" as used herein refers to a group reactive with a group having active hydrogen such as a carboxyl group (-COOH), a hydroxyl group (-OH), an amino group (-NH ₂), and the like, and is exemplified by a glycidyl group, an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, a thioisocyanate group, a maleic anhydride group, and the like. The number of reactive groups in the reactive additive is usually 1 to 20, preferably 1 to 10.

< Method for producing liquid Crystal cured film >

The method for producing a liquid crystal cured film according to the present embodiment comprises a step of forming a coating film on a base film using a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound, and a step of curing the coating film by irradiation of active energy rays from both sides of the coating film, thereby forming a liquid crystal cured film having a thickness of 2.5 [ mu ] m or more and satisfying the following formula (A) as a result of measurement by liquid chromatography.

(S/M)/(S_T/M_T)≤6.4 ...(A)

S total of peak areas of the liquid crystal monomers

M concentration of extraction solution

S _T peak area of toluene

M _T toluene solution concentration

In the step of forming a coating film, the coating film may be formed by applying a polymerizable liquid crystal composition to an alignment film formed on a base film described later and drying the composition. In the step of forming the liquid crystal cured film, the polymerizable liquid crystal compound in the coating film is polymerized by irradiation with active energy rays, whereby the liquid crystal cured film can be formed.

(Coating of polymerizable liquid Crystal composition)

Examples of the method for applying the polymerizable liquid crystal composition to the alignment film include extrusion coating, direct gravure coating, reverse gravure coating, CAP coating, slit coating, micro gravure coating, die coating, and inkjet coating. Further, a method of coating using a coater such as a dip coater, a bar coater, or a spin coater is also included. Among them, when coating is continuously performed in a Roll-to-Roll (Roll to Roll) manner, a coating method based on a micro gravure method, an inkjet method, a slit coating method, or a die coating method is preferable, and when coating on a sheet Zhang Jicai such as glass, a spin coating method with high uniformity is preferable. In the case of coating in the form of Roll-to-Roll (Roll), the composition for forming an alignment film may be coated on a substrate film to form an alignment film, and the polymerizable liquid crystal composition may be further coated continuously on the obtained alignment film.

(Drying of polymerizable liquid Crystal composition)

Examples of the drying method for removing the solvent contained in the polymerizable liquid crystal composition include natural drying, air drying, heat drying, vacuum drying, and a combination thereof. Among them, natural drying or heat drying is preferable. The drying temperature is preferably in the range of 0 to 200 ℃, more preferably in the range of 20 to 150 ℃, and even more preferably in the range of 50 to 130 ℃. The drying time is preferably 10 seconds to 10 minutes, more preferably 30 seconds to 5 minutes. This can form a coating film containing the polymerizable liquid crystal compound. The composition for forming an alignment film and the alignment polymer composition can be dried in the same manner.

(Polymerization of polymerizable liquid Crystal Compound)

As a method of polymerizing the polymerizable liquid crystal compound, photopolymerization is preferable. Photopolymerization is performed by irradiating a laminate obtained by laminating a base film, an alignment film, and a coating film containing a polymerizable liquid crystal compound in this order with active energy rays. The active energy ray to be irradiated is appropriately selected according to the type of the polymerizable liquid crystal compound contained in the dried film (particularly, the type of the photopolymerizable functional group contained in the polymerizable liquid crystal compound), the type of the photopolymerization initiator in the case of containing the photopolymerization initiator, and the amount thereof. Specifically, the light may be at least one selected from visible light, ultraviolet light, infrared light, X-rays, α -rays, β -rays, and γ -rays. Among them, ultraviolet light is preferable from the viewpoint of easy control of the progress of polymerization reaction and the viewpoint that a device widely used in the art can be used as a photopolymerization device, and the kind of polymerizable liquid crystal compound is preferably selected so that photopolymerization can be performed by ultraviolet light.

Examples of the light source of the active energy ray include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, an LED light source that emits light in a wavelength range of 380 to 440nm, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

The intensity of the ultraviolet irradiation is usually 10mW/cm ²～3,000mW/cm². The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activation of the cationic polymerization initiator or the radical polymerization initiator. The irradiation time of the light is usually 0.1 seconds to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and still more preferably 10 seconds to 1 minute. The cumulative light amount of the irradiation with such ultraviolet irradiation intensity is 10mJ/cm ²～3,000mJ/cm², preferably 50mJ/cm ²～2,000mJ/cm², more preferably 100mJ/cm ²～1,000mJ/cm², 1 or more times. When the cumulative light amount is not more than this range, curing of the polymerizable liquid crystal compound may become insufficient, and good transferability may not be obtained. In contrast, when the cumulative light amount is equal to or more than this range, the retardation film including the liquid crystal cured film may be colored.

In order to sufficiently cure a liquid crystal cured film having a thickness of 2.5 μm or more and to reduce the value of (S/M)/(S _T/M_T) and obtain good heat resistance, irradiation with active energy rays is performed from both sides. When irradiation with active energy rays is performed from both sides, irradiation is performed from the coating film side and the substrate film side of a laminate obtained by laminating a substrate film, an alignment film, and a coating film containing a polymerizable liquid crystal compound in this order. When active energy rays are irradiated from the substrate film side of the laminate, active energy rays are irradiated through the substrate film and the alignment film.

< Alignment film 3>

The alignment film has an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction.

The alignment film facilitates liquid crystal alignment of the polymerizable liquid crystal compound. The state of liquid crystal alignment such as horizontal alignment, vertical alignment, hybrid alignment, tilt alignment, etc. varies depending on the properties of the alignment film and the polymerizable liquid crystal compound, and the combination thereof may be arbitrarily selected. For example, if the alignment film is a material exhibiting horizontal alignment as an alignment regulating force, the polymerizable liquid crystal compound can be aligned horizontally or hybrid, and if it is a material exhibiting vertical alignment, the polymerizable liquid crystal compound can be aligned vertically or obliquely. The expressions horizontal, vertical, etc. refer to the direction of the optical axis of the oriented polymerizable liquid crystal compound when the plane of the liquid crystal cured film is taken as a reference. For example, vertical alignment refers to having the optical axis of the polymerizable liquid crystal compound aligned in a direction perpendicular to the plane of the liquid crystal cured film. The term "perpendicular" as used herein means 90.+ -. 20 ℃ relative to the plane of the cured liquid crystal film.

The alignment regulating force can be arbitrarily adjusted by the surface state and rubbing condition in the case where the alignment film is formed of an alignment polymer, and by the polarized light irradiation condition in the case where the alignment film is formed of a photo-alignment polymer. In addition, the liquid crystal orientation may be controlled by selecting physical properties such as surface tension and liquid crystallinity of the polymerizable liquid crystal compound.

The alignment film formed between the base film and the liquid crystal cured film is preferably an alignment film which is insoluble in a solvent used when the liquid crystal cured film is formed on the alignment film and has heat resistance in a heating process for removing the solvent and aligning the liquid crystal. As the alignment film, an alignment film including an alignment polymer, a photo-alignment film and a groove (groove) alignment film, a stretched film stretched in the alignment direction, and the like are exemplified, and in the case of being applied to a long roll film, the photo-alignment film is preferable from the viewpoint that the alignment direction can be easily controlled.

The thickness of the alignment film is usually in the range of 10nm to 5000nm, preferably in the range of 10nm to 1000nm, more preferably in the range of 30 to 300nm.

Examples of the alignment polymer used for the rubbing alignment film include polyamides and gelatins having an amide bond in the molecule, polyimides having an imide bond in the molecule, and polyamic acids, polyvinyl alcohols, alkyl modified polyvinyl alcohols, polyacrylamides, polyoxazoles, polyethylenimines, polystyrenes, polyvinylpyrrolidone, polyacrylic acids, and polyacrylates as hydrolysates thereof. Among them, polyvinyl alcohol is preferable. These alignment polymers may be used alone or in combination of 2 or more.

The rubbing method includes a method of bringing a film of an alignment polymer formed on the surface of a base film by applying the alignment polymer composition to the base film and annealing the film into contact with a rubbing roller around which a rubbing cloth is wound and rotated.

The photo-alignment film comprises a polymer, oligomer or monomer having a photoreactive group. The photo-alignment film obtains an alignment regulating force by irradiating polarized light. The photo-alignment film is more preferable from the viewpoint that the direction of the alignment regulating force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

Photoreactive groups refer to groups that generate liquid crystal alignment ability by irradiation with light. Specifically, a group that generates a photoreaction that is the origin of the liquid crystal aligning ability, such as an alignment induction or isomerization reaction, a dimerization reaction, a photocrosslinking reaction, or a photodecomposition reaction of a molecule generated by irradiation with light. Among the photoreactive groups, those that undergo dimerization or photocrosslinking are preferred in view of their excellent orientation. The photoreactive group capable of undergoing the above reaction is preferably a photoreactive group having an unsaturated bond, particularly a double bond, and more preferably a group having at least one selected from the group consisting of a carbon-carbon double bond (c=c bond), a carbon-nitrogen double bond (c=n bond), a nitrogen-nitrogen double bond (n=n bond), and a carbon-oxygen double bond (c=o bond).

Examples of the photoreactive group having a c=c bond include a vinyl group, a polyalkenyl group, a distyryl group, a styrylpyridinium group, a chalcone group, and a cinnamoyl group. From the viewpoint of easy control of reactivity and the viewpoint of exhibiting orientation restriction force at the time of photo-orientation, chalcone groups and cinnamoyl groups are preferable. Examples of the photoreactive group having a c=n bond include groups having a structure such as an aromatic schiff base and an aromatic hydrazone. Examples of the photoreactive group having an n=n bond include groups having an azobenzene basic structure such as an azophenyl group, an azonaphthyl group, an aromatic heterocyclic azo group, a bisazo group, and a formazan group, and azoxybenzene (azoxybenzene, zinan). Examples of the photoreactive group having a c=o bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have substituents such as alkyl, alkoxy, aryl, allyloxy, cyano, alkoxycarbonyl, hydroxyl, sulfonic acid, and haloalkyl.

In the case of irradiating polarized light, the polarized light may be irradiated directly from the film surface, or may be irradiated from the substrate film side so as to transmit the polarized light. In addition, the polarized light is particularly preferably substantially parallel light. Regarding the wavelength of the irradiated polarized light, it is preferable that the photoreactive group of the polymer or monomer having the photoreactive group is capable of absorbing the wavelength of the wavelength region of the light energy. Specifically, UV (ultraviolet light) having a wavelength in the range of 250 to 400nm is particularly preferable. Examples of the light source used for the polarized light irradiation include a xenon lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, an ultraviolet laser such as KrF or ArF, and more preferably a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp. The ultraviolet light of 313nm wavelength of these lamps is preferable because of its high emission intensity. The polarized light can be irradiated by irradiating the light from the light source through an appropriate polarizer. As the polarizing plate, a polarizing prism such as a polarizing filter, a glamtamesen, glatehler, or a wire grid type polarizing plate can be used.

< Substrate film 4>

The base film is a support for forming the retardation layer. As the base film, a long roll film is preferable in terms of being continuously produced. Examples of the resin constituting the base film include polyolefin such as polyethylene, polypropylene and norbornene polymer, cyclic olefin resin, polyvinyl alcohol, polyethylene terephthalate, polymethacrylate, cellulose ester such as polyacrylate, triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate, polyethylene naphthalate, polycarbonate, polysulfone, polyether sulfone, polyether ketone, polyphenylene sulfide and plastics such as polyphenylene oxide. Among them, from the viewpoint of transparency and the like when used in the optical film application, a base film containing a resin selected from any of triacetyl cellulose, a cycloolefin resin, a polymethacrylate, and polyethylene terephthalate is more preferable.

Examples of the commercially available cellulose ester substrates include "FUJITAC Film" (manufactured by Fuji Photo Film co., ltd.), "KC8UX2M", "KC8UY" and "KC4UY" (manufactured by inc.), "and the like.

Examples of commercially available cycloolefin resins include "Topas" (registered trademark) (manufactured by Ticona corporation (germany)), "ARTON" (registered trademark) (manufactured by JSR corporation), "ZEONOR" (registered trademark), and "ZEONEX" (registered trademark) (manufactured by ZEONEX corporation) and "APEL" (registered trademark) (manufactured by mitsunk chemical corporation). Such a cycloolefin resin can be formed into a base material film by a known method such as a solvent casting method or a melt extrusion method. Commercially available cycloolefin resin base materials can also be used. Examples of commercially available cycloolefin resin substrates include "Escina (registered trademark)," SCA40 "(registered trademark) (the above is made by the company of the water chemical industry)," Zeonor Film "(registered trademark) (Optes), and" Arton Film "(registered trademark) (JSR).

The thickness of the base film is preferably thin enough to enable practical handling, but if too thin, the strength tends to be low and the workability tends to be poor. The thickness of the base film is usually 5 to 300. Mu.m, preferably 10 to 200. Mu.m, more preferably 20 to 60. Mu.m, particularly preferably 30 to 50. Mu.m. In particular, if the thickness of the base film is 30 μm or more, when the polymerizable liquid crystal composition is applied to the base film and dried to form a coating film, and then the polymerizable liquid crystal compound in the coating film is polymerized to form a liquid crystal cured film, the occurrence of thermal wrinkles of the base film due to the irradiation of the drying and active energy rays tends to be suppressed, and if the thickness is 50 μm or less, the bending resistance of the optical laminate tends to be further improved. Further, the polarizing film and the liquid crystal cured film can be transferred by peeling the base film, whereby a further thinning effect can be obtained.

The substrate film preferably has a 380nm transmittance (transmittance of light having a wavelength of 380 nm) of 50% or more, more preferably 70% or more, still more preferably 80% or more, and particularly preferably 90% or more. When the 380nm transmittance of the base film is 50% or more, it is easy to cure the coating film when the liquid crystal cured film is formed by irradiation of active energy rays from one or both surfaces of the base film side to the coating film of the polymerizable liquid crystal composition, and heat resistance can be improved. The 380nm transmittance of the base film was measured by an ultraviolet-visible spectrophotometer (trade name: UV-2450, manufactured by Shimadzu corporation).

The moisture permeability of the base film is preferably 50g/m ².24 hr or more, more preferably 200g/m ².24 hr or more, and still more preferably 400g/m ².24 hr or more. If the moisture permeability of the base film is 50g/m ².24 hr or more, the adhesion can be improved when the base film is bonded to other members (polarizing plates in fig. 1) using an aqueous adhesive. The moisture permeability of the substrate film can be measured by the following method. The water vapor permeability was measured by a moisture permeability test method (cup method, according to JIS Z0208) under measurement conditions of a temperature of 40 ℃, a relative humidity of 90% RH, and a measurement time of 24 hours using a constant temperature and humidity tank. The measured water vapor permeability was used as the moisture permeability [ g/m ². 24hr ] at a temperature of 40℃and a relative humidity of 90% RH.

< Adhesive layer 5, 7>

The adhesive layer may have a function of bonding the base film of the phase difference film to the polarizing plate, and bonding the polarizing plate to the protective film. The adhesive layer may be formed of an adhesive composition.

Examples of the adhesive composition include an aqueous adhesive composition and a curable adhesive composition cured by heat or irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Examples of the aqueous adhesive composition include a composition obtained by dissolving a polyvinyl alcohol resin or a urethane resin as a main component in water and a composition obtained by dispersing a polyvinyl alcohol resin or a urethane resin as a main component in water. The aqueous adhesive composition may further contain a curable component such as a polyaldehyde, a melamine compound, a zirconia compound, a zinc compound, a glyoxal compound, a water-soluble epoxy resin, and a crosslinking agent. Examples of the aqueous adhesive composition include an adhesive composition described in japanese patent application laid-open publication No. 2010-191389, an adhesive composition described in japanese patent application laid-open publication No. 2011-107686, a composition described in japanese patent application laid-open publication No. 2020-172088, and a composition described in japanese patent application laid-open publication No. 2005-208456.

The curable adhesive composition is preferably an active energy ray curable adhesive composition which contains a curable (polymerizable) compound as a main component and is cured by irradiation with active energy rays. Examples of the active energy ray-curable adhesive composition include a cationic polymerizable adhesive composition containing a cationic polymerizable compound as a curable compound, a radical polymerizable adhesive composition containing a radical polymerizable compound as a curable compound, and a mixed adhesive composition containing both a cationic polymerizable compound and a radical polymerizable compound as a curable compound.

The cationically polymerizable compound is a compound or oligomer which is cured by cationic polymerization reaction by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, X-rays, or the like, and specifically, an epoxy compound, an oxetane compound, a vinyl compound, or the like is exemplified.

Examples of the epoxy compound include alicyclic epoxy compounds such as 3',4' -epoxycyclohexylmethyl 3, 4-epoxycyclohexane carboxylate (compounds having 1 or more epoxy groups bonded to alicyclic rings in the molecule), aromatic epoxy compounds such as diglycidyl ether of bisphenol A (compounds having an aromatic ring and an epoxy group in the molecule), aliphatic epoxy compounds such as 2-ethylhexyl glycidyl ether and 1, 4-butanediol diglycidyl ether (compounds having at least 1 oxirane ring bonded to aliphatic carbon atoms in the molecule), and the like.

Examples of oxetane compounds include compounds having 1 or more oxetane rings in the molecule, such as 3-ethyl-3- { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetane.

The cationically polymerizable adhesive composition preferably contains a cationic polymerization initiator. The cationic polymerization initiator may be a thermal cationic polymerization initiator or a photo cationic polymerization initiator. Examples of the cationic polymerization initiator include aromatic diazonium salts such as benzodiazonium hexafluoroantimonate, aromatic iodonium salts such as diphenyliodonium tetrakis (pentafluorophenyl) borate, aromatic sulfonium salts such as triphenylsulfonium hexafluorophosphate, and iron-arene complexes such as xylene-cyclopentadienyl iron (II) hexafluoroantimonate. The content of the cationic polymerization initiator is usually 0.1 to 10 parts by mass per 100 parts by mass of the cationic polymerizable compound. More than 2 cationic polymerization initiators may be included. Examples of the cationically polymerizable adhesive composition include those described in JP 2016-126345, international publication No. 2019/10315, and JP 2021-113969.

The radical polymerizable compound is a compound or oligomer which is cured by radical polymerization reaction by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, X-rays, or the like, and specifically, a compound having an ethylenically unsaturated bond is exemplified. Examples of the compound having an ethylenically unsaturated bond include a (meth) acrylic compound having 1 or more (meth) acryloyl groups in the molecule, a vinyl compound having 1 or more vinyl groups in the molecule, and the like. Examples of the (meth) acrylic compound include (meth) acryl-containing compounds such as (meth) acrylic oligomers having at least 2 (meth) acryl groups in the molecule, which are obtained by reacting 2 or more kinds of (meth) acrylate monomers having at least 1 (meth) acryloyloxy group in the molecule, a (meth) acrylamide monomer, and a functional group-containing compound. In the present specification, (meth) acryl means any one of acryl or methacryl.

The radical polymerization type adhesive composition preferably contains a radical polymerization initiator. The radical polymerization initiator may be a thermal radical polymerization initiator or a photo radical polymerization initiator. Examples of the radical polymerization initiator include acetophenone-based initiators such as acetophenone and 3-methylacetophenone, benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone and 4,4' -diaminobenzophenone, benzoin ether-based initiators such as benzoin propyl ether and benzoin diethyl ether, thioxanthone-based initiators such as 4-isopropylthioxanthone, xanthone and fluorenone. The content of the radical polymerization initiator is usually 0.1 to 10 parts by mass per 100 parts by mass of the radical polymerizable compound. More than 2 radical polymerization initiators may be included. Examples of the radical polymerizable adhesive composition include radical polymerizable compositions described in Japanese patent application laid-open No. 2016-126345, japanese patent application laid-open No. 2016-153474, and International publication No. 2017/183335.

The active energy ray-curable adhesive composition may contain, if necessary, an additive such as an ion scavenger, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, a defoaming agent, an antistatic agent, a leveling agent, a solvent, and the like.

The bonding of the two layers by the adhesive layer may be performed by applying the adhesive composition to at least one bonding surface selected from the bonding surfaces of the two layers, overlapping the two layers via the application layer of the adhesive composition, pressing the two layers from above and below by using a bonding roller or the like, and then drying the adhesive layer, curing the adhesive layer by irradiation with active energy rays, or curing the adhesive layer by heating.

Before forming the coating layer of the adhesive layer, at least one bonding surface selected from the bonding surfaces of the two layers may be subjected to an easy-to-adhere treatment such as saponification treatment, corona treatment, plasma treatment, primer treatment, anchor coating treatment, and the like.

The adhesive composition may be formed by various coating methods such as die coater, comma coater, gravure coater, bar coater, and blade coater.

The light irradiation intensity upon irradiation with the active energy ray is determined according to the composition of the active energy ray-curable adhesive composition, and is not particularly limited, but is preferably 10mW/cm ² or more and 1,000mW/cm ² or less. The irradiation intensity is preferably an intensity in a wavelength region effective for activation of the photo-cationic polymerization initiator or the photo-radical polymerization initiator. The irradiation is performed 1 or more times at such a light irradiation intensity that the cumulative light amount is preferably 10mJ/cm ² or more, more preferably 100mJ/cm ² or more and 1,000mJ/cm ² or less.

The light source used for polymerization curing of the active energy ray-curable adhesive composition is not particularly limited, and examples thereof include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a halogen lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

The thickness of the adhesive layer formed of the aqueous adhesive composition may be, for example, 5 μm or less, preferably 1 μm or less, more preferably 0.5 μm or less, and may be 0.01 μm or more, preferably 0.05 μm or more.

The thickness of the adhesive layer formed from the active energy ray-curable adhesive composition may be, for example, 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less, and may be 0.1 μm or more, preferably 0.5 μm or more, more preferably 1 μm or more.

< Polarizing plate 6>

As the polarizing plate, for example, a film obtained by uniaxially stretching a polyvinyl alcohol resin film (hereinafter, also referred to as "PVA film") or the like in a state where iodine and an organic dichroic dye are impregnated into a polymer can be used. The polarizing plate having the above-described structure can be generally produced by a process of uniaxially stretching a PVA-based film, a process of adsorbing a dichroic dye such as iodine by dyeing the PVA-based film, a process of treating the PVA-based film adsorbed with the dichroic dye with a crosslinking agent such as an aqueous boric acid solution, and a process of washing with water after the treatment with the crosslinking agent such as an aqueous boric acid solution. The polarizer may contain a crosslinking agent.

The thickness of the polarizing plate is usually 30 μm or less, preferably 18 μm or less, more preferably 15 μm or less, and still more preferably 12 μm or less. By setting the thickness of the polarizing plate to the above upper limit value or less, the bending resistance of the optical laminate can be further improved. The thickness of the polarizing plate is usually 1 μm or more, but may be, for example, 5 μm or more.

The uniaxial stretching of the PVA-based film may be performed before dyeing based on the dichroic dye, simultaneously with dyeing, or after dyeing. In the case of uniaxial stretching after dyeing, the uniaxial stretching may be performed before boric acid treatment or may be performed in boric acid treatment. Of course, the uniaxial stretching may be performed in a plurality of stages as shown here. As the uniaxial stretching, a method of stretching uniaxially in the film conveying direction between rolls having different peripheral speeds, a method of stretching uniaxially in the film conveying direction using a hot roll, a method of stretching in the width direction using a tenter, and the like can be employed. The uniaxial stretching may be performed by dry stretching in which stretching is performed in the atmosphere, or may be performed by wet stretching in which stretching is performed in a state in which a PVA-based film is swollen with a solvent such as water. The stretching ratio is usually about 3 to 8 times. The thermoplastic resin film may be coated with an aqueous solution containing polyvinyl alcohol, then dried, and stretched together with the thermoplastic resin film by the above method.

Dyeing of the PVA film with the dichroic dye can be performed, for example, by immersing the PVA film in an aqueous solution containing the dichroic dye. As the dichroic dye, specifically, iodine and a dichroic organic dye can be used. The PVA-based film is preferably subjected to a treatment of swelling by immersing in water before the dyeing treatment.

In the case of using iodine as a dichroic dye, a method of immersing a PVA-based film in an aqueous solution containing iodine and potassium iodide is generally employed for dyeing. The iodine content in the aqueous solution is usually about 0.01 to 1 part by mass per 100 parts by mass of water, and the potassium iodide content is usually about 0.5 to 20 parts by mass per 100 parts by mass of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 ℃. The immersion time (dyeing time) in the aqueous solution is usually about 20 to 1,800 seconds.

On the other hand, in the case of using a dichroic organic dye as a dichroic dye, a method of immersing a PVA-based film in an aqueous solution containing a water-soluble dichroic organic dye to dye is generally employed. The content of the dichroic organic dye in the aqueous solution is usually about 0.0001 to 10 parts by mass, preferably 0.001 to 1 part by mass per 100 parts by mass of water. The aqueous dye solution may contain an inorganic salt such as sodium sulfate as a dyeing auxiliary. The temperature of the aqueous dichroic organic dye solution used for dyeing is usually about 20 to 80 ℃. The immersion time (dyeing time) in the aqueous solution is usually about 10 to 1,800 seconds.

The boric acid treatment after dyeing based on the dichroic dye may be performed by a method of immersing the dyed PVA-based film in an aqueous solution containing boric acid. The content of boric acid in the aqueous solution containing boric acid is usually about 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. In the case of using iodine as the dichroic dye, the aqueous solution containing boric acid preferably contains potassium iodide. The content of potassium iodide in the aqueous solution containing boric acid is usually about 0.1 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. The immersion time in the aqueous solution containing boric acid is usually about 60 to 1,200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the aqueous solution containing boric acid is usually 50 ℃ or higher, preferably 50 to 85 ℃, and more preferably 60 to 80 ℃.

The PVA film after boric acid treatment is usually subjected to a water washing treatment. The water-washing treatment can be performed, for example, by immersing the boric acid-treated PVA-based film in water. The temperature of water in the water washing treatment is usually about 5 to 40 ℃. The immersion time is usually about 1 to 120 seconds.

After washing with water, drying treatment was performed to obtain a polarizing plate. The drying treatment may be performed using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually about 30 to 100 ℃, preferably 50 to 80 ℃. The drying time is usually about 60 to 600 seconds, preferably 120 to 600 seconds. The moisture content in the polarizing plate is reduced to a practical level by the drying treatment. The water content is usually about 5 to 20 mass%, preferably 8 to 15 mass% relative to the total mass of the polarizing plate. If the moisture content is 5 mass% or more, the polarizer has sufficient flexibility, and therefore, damage or breakage after drying can be suppressed. In addition, if the moisture content is 20 mass% or less, the polarizing plate has sufficient thermal stability.

As described above, a polarizing plate in which a dichroic dye is adsorbed and aligned to a PVA film can be produced.

The polarization properties of the polarizer can be measured using a spectrophotometer. For example, the transmittance (T ¹) in the transmission axis direction (the direction perpendicular to the alignment) and the transmittance (T ²) in the absorption axis direction (the direction perpendicular to the alignment) can be measured by a two-beam method using a device having a prism polarizer attached to a spectrophotometer in the visible light wavelength range of 380nm to 780 nm. Regarding the polarization performance in the visible light range, the individual transmittance and polarization degree at each wavelength are calculated using the following formulas (formula 1) and (formula 2), and the visibility (japanese: sensitivity) is further corrected by using the 2-degree field of view (C light source) of JIS Z8701, whereby the individual transmittance (Ty) and the visibility-corrected polarization degree (Py) can be calculated. The hues a ^＊ and b ^＊ in the L ^＊a^＊b^＊ (CIE) color system were calculated from the transmittance measured in the same manner using the color matching function (japanese: number of equal colors guan) of the C light source, whereby the hues of the polarizer alone (monomer hues), the hues of the polarizer arranged in parallel (parallel hues), and the hues of the polarizer arranged in orthogonal (orthogonal hues) were obtained. The closer the values of a ^＊ and b ^＊ are to 0, the more neutral the hue can be judged.

Monomer transmittance (%) = (T ¹＋T²)/2..(formula 1)

Degree of polarization (%) = (T ¹－T²）/（T¹＋T²) ×100..(formula 2)

The visibility correction polarization degree Py of the polarizing plate is usually 80% or more, preferably 90% or more, more preferably 95% or more, further preferably 98% or more, particularly preferably 99% or more, and if 99.9% or more, can be suitably used for a liquid crystal display. Improving the visibility correction polarization Py of the polarizer is advantageous in improving the antireflection function of the optical laminate. If the visibility correction polarization degree Py is less than 80%, the antireflection function when used as an antireflection film may not be exhibited.

The visibility of the polarizing plate increases as the visibility correction monomer transmittance Ty increases, but as the relationship between (formula 1) and (formula 2) shows, the degree of polarization decreases if the monomer transmittance is excessively increased. Therefore, the visibility correction monomer transmittance Ty is preferably 30% or more, more preferably 35% or more, further preferably 38% or more, and particularly preferably 40% or more. The visibility correction monomer transmittance Ty is preferably 60% or less, more preferably 55% or less, and further preferably 50% or less. From the viewpoint of improving the reflection color tone, it is particularly preferably 43% or more and 46% or less. If the visibility correction monomer transmittance Ty is too high, the visibility correction polarization Py becomes too low, and the antireflection function when used as an antireflection film may become insufficient.

< Protective film 8>

The protective film has a function of protecting the surface of the polarizing plate. The polarizing plate and the protective film may be directly laminated to each other. Here, "direct lamination" includes a method of laminating a polarizer by self-adhesion of a protective film and a method of laminating a polarizer via an adhesive layer or an adhesive layer. In order to improve the adhesion to the polarizing plate, the protective film may be subjected to a surface treatment (for example, corona treatment or the like), or may be formed with a thin layer such as an undercoat layer (also referred to as an easy-to-adhere layer).

As the protective film, for example, a resin film excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, stretchability, and the like can be used. The resin film may be a thermoplastic resin film. Specific examples of such resins include cellulose resins such as triacetyl cellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyether sulfone resins, polysulfone resins, polycarbonate resins, polyamide resins such as nylon and aromatic polyamide resins, polyimide resins, polyolefin resins such as polyethylene, polypropylene and ethylene-propylene copolymer, cyclic polyolefin resins having a ring system and a norbornene structure (also referred to as norbornene resins), (meth) acrylic resins such as polymethyl methacrylate, polyarylate resins, polystyrene resins, polyvinyl alcohol resins and mixtures thereof. The protective film of this material can be easily obtained from the market. Further, a thermosetting resin such as a (meth) acrylic resin, a urethane resin, a (meth) acrylic urethane resin, an epoxy resin, or a silicone resin, an ultraviolet curable resin, or the like can be mentioned. In the present specification, (meth) acrylic acid means either acrylic acid or methacrylic acid.

The chain polyolefin resin includes a homopolymer of a chain olefin such as a polyethylene resin (polyethylene resin which is a homopolymer of ethylene, a copolymer mainly composed of ethylene) and a polypropylene resin (polypropylene resin which is a homopolymer of propylene, a copolymer mainly composed of propylene), and a copolymer containing 2 or more chain olefins.

The cyclic polyolefin resin is a general term for a resin obtained by polymerizing a cyclic olefin as a polymerization unit, and examples thereof include resins described in JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Examples of the cyclic polyolefin resin include a ring-opened (co) polymer of a cyclic olefin, an addition polymer of a cyclic olefin, a copolymer (typically, a random copolymer) of a cyclic olefin and a chain olefin such as ethylene or propylene, a graft polymer obtained by modifying the copolymer with an unsaturated carboxylic acid or a derivative thereof, and a hydrogenated product thereof. Among them, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.

The polyester resin is a resin having an ester bond in the main chain, and is usually a polycondensate of a polycarboxylic acid or a derivative thereof and a polyhydric alcohol. As the polycarboxylic acid or derivative thereof, a 2-membered dicarboxylic acid or derivative thereof may be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl naphthalate, and the like. As the polyhydric alcohol, a 2-membered diol may be used, and examples thereof include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, cyclohexanedimethanol, and the like. As a representative example of the polyester resin, polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol, is given.

The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of the cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Further, there may be mentioned a cellulose ester resin obtained by modifying a part of hydroxyl groups of a copolymer having a plurality of polymerization units constituting the cellulose ester resin with other substituents. Among them, cellulose triacetate (triacetyl cellulose) is particularly preferable.

The (meth) acrylic resin is a resin mainly composed of a compound having a (meth) acryloyl group. Specific examples of the (meth) acrylic resin include, for example, poly (meth) acrylic esters such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester- (meth) acrylic acid copolymer, methyl methacrylate-styrene copolymer (MS resin and the like), copolymer of methyl methacrylate and a compound having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl methacrylate copolymer and the like). Preferably, a polymer containing a poly (C1-6 alkyl (meth) acrylate such as poly (methyl (meth) acrylate) as a main component is used, and more preferably, a methyl methacrylate-based resin containing methyl methacrylate as a main component (50 to 100 mass%, preferably 70 to 100 mass%) is used.

The polycarbonate resin includes a polymer in which monomer units are bonded via a carbonate group. The polycarbonate resin may be a resin called a modified polycarbonate, a copolycarbonate, or the like, in which the polymer skeleton is modified. Details of polycarbonate resins are described in, for example, japanese patent application laid-open No. 2012-31370. The disclosure of this patent document is incorporated by reference into the present specification.

In the present invention, the base film used as a support for the liquid crystal cured film is then bonded to the polarizer and functions as a protective film for protecting one surface of the polarizer. This can reduce the number of steps for manufacturing the optical laminate.

The thickness of the protective film is preferably 0.1 μm to 60. Mu.m, more preferably 0.5 μm to 40. Mu.m, still more preferably 1 μm to 30. Mu.m.

From the viewpoint of improving the reflection color tone, the 380nm transmittance (transmittance of light having a wavelength of 380 nm) of the protective film is preferably 10% or less, more preferably 7% or less, further preferably 5% or less, particularly preferably 3% or less, and most preferably 1.5% or less. The weather resistance of the optical laminate can be improved by setting the 380nm transmittance of the protective film to 10% or less. The 380nm transmittance of the protective film can be measured by the same method as the 380nm transmittance of the base film.

The protective film may be used so as to be disposed on the viewing side of the polarizing plate. Therefore, the protective film may be subjected to surface treatments such as hard coat treatment, antireflection treatment, anti-sticking treatment, and antiglare treatment, as necessary. Further, the protective film may be subjected to a treatment (typically, a (elliptical) polarization function and an ultra-high phase difference) to improve visibility when viewed through a polarized sunglasses, if necessary. By performing such a process, excellent visibility can be achieved even when the display screen is viewed through a polarizing lens such as a polarizing sunglasses. Therefore, the optical laminate including the protective film subjected to such a treatment can be suitably used for an image display device that can be used outdoors.

The protective film can be produced by stretching a film containing the thermoplastic resin. The stretching treatment includes uniaxial stretching, biaxial stretching, and the like. Examples of the stretching direction include a mechanical flow direction (MD) of an unstretched film, a direction (TD) perpendicular thereto, and a direction oblique to the mechanical flow direction (MD). The biaxial stretching may be simultaneous biaxial stretching in which the stretching is simultaneous in 2 stretching directions, or sequential biaxial stretching in which the stretching is performed in a predetermined direction and then in other directions. The stretching treatment may be performed, for example, by stretching in the longitudinal direction (machine direction: MD) using a nip roller of 2 or more pairs of nip rollers having an increased peripheral speed on the outlet side, or by holding both side ends of the unstretched film with chucks and expanding in The Direction (TD) orthogonal to the machine direction. In this case, the phase difference value and the wavelength dispersion can be controlled by adjusting the film thickness or the stretching ratio. In addition, by adding the wavelength dispersion adjusting agent to the resin, the wavelength dispersion value can be controlled.

The protective film may contain any appropriate additive according to the purpose. Examples of the additives include antioxidants such as hindered phenols, phosphorus-based and sulfur-based antioxidants, light stabilizers, ultraviolet absorbers, weather stabilizers, heat stabilizers, reinforcing materials such as glass fibers and carbon fibers, flame retardants such as near infrared absorbers, triallyl phosphate and antimony oxide, antistatic agents such as anionic, cationic and nonionic surfactants, colorants such as inorganic pigments, organic pigments and dyes, organic fillers and inorganic fillers, resin modifiers, plasticizers, lubricants, and retardation reducers. The kind, combination, content, and the like of the additives contained may be appropriately set according to the purpose, desired characteristics, and the like.

In addition, a coating layer (surface treatment layer) may be provided on the outer surface of the protective film in order to impart desired surface optical characteristics or other features. Specific examples of the surface treatment layer include a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer. The method for forming the surface treatment layer is not particularly limited, and a known method can be used. The surface treatment layer may be formed on one surface of the protective film or on both surfaces.

The hard coat layer has a function of improving the surface hardness of the protective film, and is provided for the purpose of preventing scratches on the surface, and the like. The hard coat layer preferably has a pencil hardness of H or a value harder than H as measured by the pencil hardness test (measured by placing an optical film having the hard coat layer on a glass plate) specified in JIS K5600-5-4:1999 "general test method for coating materials-part 5: mechanical properties of coating film-part 4: scratch hardness (pencil method)".

The material forming the hard coat layer is usually a material cured by heat or light. Examples thereof include organic hard coat materials such as organosilicone-based, melamine-based, epoxy-based, (meth) acrylic-based, urethane (meth) acrylate-based and inorganic hard coat materials such as silica. Among them, urethane (meth) acrylate-based or polyfunctional (meth) acrylate-based hard coat materials are preferably used in view of good adhesion to protective films and excellent productivity. In the present specification, (meth) acrylate means any of acrylate and methacrylate.

The hard coat layer may contain various fillers as desired for the purpose of achieving adjustment of refractive index, improvement of flexural modulus of elasticity, stabilization of volume shrinkage, and improvement of even heat resistance, antistatic property, antiglare property, and the like. The hard coat layer may contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, leveling agents, and defoaming agents.

To further increase the strength, the hard coat layer may contain additives. The additive is not limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof. In addition, the thicker the hard coat layer is, the better the hardness is, but if it is too thick, it is easily broken at the time of cutting, so it may be 1 μm to 20 μm or 2 μm to 10 μm. The thickness of the hard coating layer is preferably 3 μm to 7 μm.

The antiglare layer is a layer having a fine uneven shape on the surface, and is preferably formed using the hard coat material.

The antiglare layer having a fine uneven shape on the surface can be formed by 1) a method of forming a coating film containing fine particles on a protective film and providing the uneven shape based on the fine particles, and 2) a method of forming a coating film containing fine particles or not on a protective film, and then pressing the coating film against a mold (roll or the like) to which the uneven shape is imparted to the surface, thereby transferring the uneven shape (also referred to as an embossing method).

The antireflection layer is a layer for reducing reflection of external light on the surface of the protective film for a person observing the protective film, and generally has a reflectance of 1.5% or less for visible light. Such an antireflection layer having a reflectance can be typically formed by laminating a high refractive index layer having a high refractive index and a low refractive index layer having a low refractive index, and by using the method and materials described in japanese patent application laid-open No. 2021-6929. By adjusting the refractive index and the thickness of each layer, the reflected light from each layer can be attenuated mutually, and an excellent antireflection function can be realized.

As described in detail later, an antireflective layer including a high refractive index layer and a low refractive index layer is preferable because it is extremely simple to handle if the antireflective layer is manufactured using a coating composition capable of forming the high refractive index layer and the low refractive index layer separately. Here, an example of a coating composition capable of forming a high refractive index layer and a low refractive index layer is given. The coating composition is in a liquid state and contains a suitable curable resin and additives as required. The coating composition capable of forming a high refractive index layer (composition for forming a high refractive index layer) is obtained by dissolving a curable resin such as urethane acrylate and an initiator (photopolymerization initiator) for photopolymerization such as acetophenone, benzophenone, benzildimethyl ketal, α -hydroxyalkylbenzophenone, α -aminoalkylbenzophenone, thioxanthone in a solvent such as methyl ethyl ketone or methyl isobutyl ketone. In order to improve the coatability, a leveling agent, preferably a fluorine-based leveling agent, may be contained. In addition, as a coating composition capable of forming a low refractive index layer (composition for forming a low refractive index layer), silica particles are dispersed in a solution in which a solvent such as 1-methoxy-2-propyl acetate or methyl isobutyl ketone is dissolved in a binder resin such as polyethylene glycol diacrylate or pentaerythritol (tri/tetra) acrylate which is a curable resin, and an initiator (photopolymerization initiator) for photopolymerization such as acetophenone, benzophenone, benzil dimethyl ketal, α -hydroxyalkylbenzophenone, α -aminoalkylbenzophenone, or thioxanthone. In order to improve the coatability, a fluorine-based leveling agent may be included. The coating composition capable of forming the high refractive index layer and the low refractive index layer are only examples, and the composition for forming the high refractive index layer and the composition for forming the low refractive index layer are preferably optimized according to the characteristics of the antireflection layer to be formed.

The antireflection layer may be provided with a low refractive index layer, for example. In addition, a multilayer structure may be provided in which a high refractive index layer and/or a medium refractive index layer is further provided between the protective film and the low refractive index layer.

The low refractive index layer may be formed by a method of applying a coating liquid containing a curable resin such as the curable resin, a light-transmitting resin such as a metal alkoxide polymer, and inorganic particles, and then curing the coating layer as necessary. Examples of the inorganic particles include low refractive particles such as LiF (refractive index 1.4), mgF (refractive index 1.4), 3naf·alf (refractive index 1.4), alF (refractive index 1.4), na ₃AlF₆ (refractive index 1.33), and hollow silica particles.

The antistatic layer is provided for the purpose of imparting conductivity to the surface of the protective film, suppressing the influence of static electricity, and the like. For example, a method of applying a resin composition containing a conductive substance (antistatic agent) to a protective film can be used for forming the antistatic layer. For example, an antistatic hard coat layer can be formed by allowing an antistatic agent to coexist with the hard coat material used in the formation of the above hard coat layer.

The stain-proofing layer is provided for imparting water repellency, oil repellency, perspiration resistance, stain resistance, and the like. Suitable materials for forming the anti-fouling layer are fluorine-containing organic compounds. Examples of the fluorine-containing organic compound include fluorocarbon, perfluorosilane, and polymer compounds thereof. The method for forming the antifouling layer may be physical vapor deposition, chemical vapor deposition, wet coating, or the like, typified by vapor deposition or sputtering, depending on the material to be formed. The average thickness of the antifouling layer is usually about 1 to 50nm, preferably 3 to 35nm.

< Optical laminate 100>

The total thickness of the optical laminate including the layers described above may be 70 μm or more, preferably 80 μm or more, from the viewpoint of obtaining good bending resistance. In addition, the particle size may be 150 μm or less, preferably 120 μm or less.

In addition, the ratio of the thickness of the liquid crystal cured film to the total thickness of the optical laminate may be 2.15% or more. When the ratio is 2.15% or more, occurrence of interference unevenness can be suppressed and high bending resistance can be obtained. From the above viewpoints, the ratio of the thickness of the liquid crystal cured film to the total thickness of the optical laminate is preferably 2.3% or more, and more preferably 2.5% or more. The ratio of the thickness of the liquid crystal cured film to the total thickness of the optical laminate may be 5% or less, may be 4% or less, may be 3.5% or less, or may be 3% or less.

The optical laminate may be provided with a separator for protecting the outer surface of the adhesive layer. The separator is a film temporarily bonded to protect the surface of the adhesive layer until the adhesive layer is bonded to an image display element (an organic EL display element or the like) or other optical member. The thickness of the separator is not included in the above-described "total thickness of the optical laminate". The separator is generally composed of a thermoplastic resin film having a release treatment on one surface thereof with a release agent such as a silicone-based or fluorine-based release agent, and the release treated surface thereof is bonded to the pressure-sensitive adhesive layer.

Examples of the thermoplastic resin constituting the separator include polyethylene resins such as polyethylene, polypropylene resins such as polypropylene, and polyester resins such as polyethylene terephthalate and polyethylene naphthalate.

The thickness of the separator is, for example, 10 μm or more and 100 μm or less. If the thickness of the separator is 100 μm or less, the force caused when the separator is peeled off can be suppressed low, and thus peeling is advantageous, and if it is 10 μm or more, generation of an indentation in the adhesive layer due to foreign matter during processing can be suppressed, which is preferable.

The film formed of the polyester resin may be stretched without stretching, but is preferably stretched from the viewpoint of improving the strength, and may be uniaxially stretched or biaxially stretched.

The separator may include an antistatic layer. The antistatic layer may be provided on a surface of the separator opposite to the surface on which the adhesive layer is laminated, for example.

[ Method for producing optical laminate ]

The method for producing an optical laminate according to the present embodiment is a method for producing an optical laminate having a protective film, a polarizing plate, a base film, and a liquid crystal cured film in this order, and includes a step of producing the liquid crystal cured film by the method for producing a liquid crystal cured film. By this production method, a liquid crystal cured film having a low value of (S/M)/(S _T/M_T) can be formed, and therefore the optical laminate can have high heat resistance.

[ Image display device ]

The image display device includes the optical laminate and an image display element (an organic EL display element or the like). The optical layered body is disposed on the viewing side of the image display element. The optical laminate may be bonded to the image display element via the adhesive layer.

The image display device is not particularly limited, and examples thereof include an organic electroluminescence (organic EL) display device, an inorganic electroluminescence (inorganic EL) display device, a liquid crystal display device, an electroluminescence display device, and the like.

The image display device can be used as mobile devices such as smart phones and tablet computers, televisions, digital photo frames, electronic labels, measuring devices or metering instruments, office equipment, medical equipment, electronic computing equipment and the like.

[ Example ]

The present invention will be described in further detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, "parts" and "%" indicating the amount or content used are mass-based unless otherwise specified.

Example 1

< Preparation of liquid Crystal cured film >

(1) Preparation of composition for Forming photo-alignment film

2 Parts of a polymer (1) having a number average molecular weight of 28000 represented by the following formula (1) and 98 parts of o-xylene were mixed, and the resultant mixture was stirred at 80 ℃ for 1 hour, thereby obtaining a composition for forming a photo-alignment film.

[ Chemical formula 8]

[ Wherein Me represents a methyl group. ]

(2) Preparation of polymerizable liquid Crystal composition (A) for Forming liquid Crystal cured film

A polymerizable liquid crystal compound A-1 (86.0 parts) represented by the following formula (A-1), a polymerizable liquid crystal compound A-2 (14.0 parts) represented by the following formula (A-2), a polyacrylate compound (leveling agent, trade name: BYK-361N, manufactured by BYK-Chemie Co., ltd.), 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (photopolymerization initiator, manufactured by Ciba SPECIALTY CHEMICALS Co., ltd.; irgacure 369, 3.0 parts), and LALOMER LR9000 (trade name, manufactured by BASF Japan Co., ltd.) (2.0 parts) were mixed. Anisole was further added so that the solid content concentration became 9%. A polymerizable liquid crystal composition (A) comprising a polymerizable liquid crystal compound A-1 and a polymerizable liquid crystal compound A-2 was obtained. The polymerizable liquid crystal compound A-1 was synthesized by the method described in JP-A2010-31223. The maximum absorption wavelength λmax (LC) of the polymerizable liquid crystal compound A-1 measured in chloroform was 350nm.

[ Chemical formula 9]

[ Chemical formula 10]

(3) Fabrication of retardation film

A base film was produced by subjecting a triacetyl cellulose film (manufactured by KONICA MINOLTA Co., ltd., trade name: KC4CZ-TAC, thickness 40 μm) to 1 treatment using a corona treatment apparatus (manufactured by CHUNICA Motor Co., ltd., trade name: AGF-B10) at an output of 0.3kW and a treatment rate of 3 m/min. The substrate film had a 380nm transmittance of 91% and a moisture permeability of 700g/m ².24 hr. The composition for forming a photo-alignment film was applied onto the corona-treated surface of the base film by a bar coater, dried at 80℃for 1 minute, and subjected to polarized UV exposure with an accumulated light amount of 100mJ/cm ² by using a polarized UV irradiation apparatus (SPOTCURE SP-7 with polarizer unit (trade name, manufactured by USHIO Motor Co., ltd.) to form a photo-alignment film. The thickness of the obtained photo-alignment film was measured by ellipsometer M-220 (trade name, manufactured by Japanese spectroscopic Co., ltd.), and found to be 100nm.

Next, the previously prepared polymerizable liquid crystal composition (a) containing a polymerizable liquid crystal compound was applied onto the above photo-alignment film by a bar coater, and dried at 120 ℃ for 1 minute to form a coating film containing a polymerizable liquid crystal compound, thereby obtaining a laminate composed of a triacetyl cellulose film (base film)/photo-alignment film/coating film. Then, ultraviolet rays (cumulative light amount at wavelength 313nm under nitrogen atmosphere: 500mJ/cm ²) were irradiated from the surface of the laminate on the film side facing the coating film using a high-pressure mercury lamp (trade name: unicure VB-15201BY-A, manufactured BY USHIO Motor Co., ltd.) and further, ultraviolet rays were irradiated from the surface of the laminate on the substrate film side under the same conditions, whereby the coating film was cured to form a liquid crystal cured film. Thus, a retardation film was formed as a laminate composed of a triacetyl cellulose film (base film)/a photo-alignment film/a liquid crystal cured film. The thickness of the obtained cured liquid crystal film was measured by a laser microscope (trade name: LEXT, manufactured by Olympic Co., ltd.) and found to be 2.7. Mu.m. The value of (S/M)/(S _T/M_T) in the liquid-crystal-cured film extraction liquid chromatography measurement was 4.2. The liquid chromatography measurement was performed in a state of a retardation film which is a laminate of a base film, a photo-alignment film, and a liquid crystal cured film. The retardation film was used for curing the coating film by ultraviolet irradiation to form a liquid crystal cured film, and the time period was 24 hours or longer. The measurement method of the extraction liquid chromatography measurement is as described above.

< Preparation of optical laminate >

(4) Production of polarizer 1 (iodine PVA type polarizer)

(Swelling treatment Process)

A polyvinyl alcohol film (raw film) having a thickness of 30 μm (manufactured by kohly corporation, average polymerization degree 2400, saponification degree 99.9 mol%) was transported while being continuously wound out from the raw roll, and immersed in a swelling bath in which pure water at 20 ℃ was added for 30 seconds. In this swelling treatment step, the stretching ratio was set to 2.5 times based on the raw film.

(Dyeing treatment Process)

Next, the film after the swelling treatment step was immersed in a dyeing bath at 30 ℃ for 120 seconds, in which the mass ratio of pure water/potassium iodide/iodine/boric acid was 100/2/0.01/0.3. In this dyeing process, the stretching ratio based on the film after the swelling process is set to 1.1 times.

(Crosslinking treatment Process)

Next, the film after the dyeing treatment was immersed in a crosslinking bath at 56 ℃ with a mass ratio of pure water/potassium iodide/boric acid of 100/12/4 for 70 seconds. In the crosslinking treatment step, the stretching ratio was set to 1.9 times based on the film after the dyeing treatment step.

(Complementary color treatment Process)

Next, the film after the crosslinking treatment step was immersed in a crosslinking bath at 40 ℃ with a mass ratio of potassium iodide/boric acid/pure water of 9/2.9/100 for 10 seconds.

(Cleaning treatment step)

Next, the film after the complementary color treatment step was immersed in a cleaning bath to which pure water at 5 ℃ was added for 5 seconds.

(Drying treatment Process)

Next, the film after the cleaning treatment step was passed through a drying oven, and thereby heated and dried at 80 ℃ for 190 seconds, to produce a polarizing plate 1 (polarizing film). The thickness of the resulting polarizing plate 1 was 12. Mu.m. The visibility correction monomer transmittance Ty of the polarizing plate 1 was 44.5%.

(5) Preparation of aqueous adhesive

An aqueous polyvinyl alcohol solution was prepared by dissolving 3 parts by mass of carboxyl group-modified polyvinyl alcohol (trade name: KL-318, manufactured by Kagaku Kogyo Co., ltd.) with respect to 100 parts by mass of water. An aqueous adhesive (dry curable adhesive) was obtained by mixing a water-soluble polyamide epoxy resin (trade name: sumirezResin 650,650 (30), solid content concentration 30% by mass, manufactured by the chemical industry, cyclobalanoside) with the obtained aqueous solution at a ratio of 1.5 parts by mass with respect to 100 parts by mass of water.

(6) Production of adhesive sheet

(6-1) Preparation of acrylic resin solution

A mixed solution of 81.8 parts of ethyl acetate, 98.0 parts of butyl acrylate and 2.0 parts of acrylic acid was charged into a reaction vessel equipped with a condenser, a nitrogen inlet, a thermometer and a stirrer, and the internal temperature was raised to 55℃while the air in the apparatus was replaced with nitrogen gas to remove oxygen. Then, a solution of 0.14 parts of azobisisobutyronitrile (polymerization initiator) dissolved in 10 parts of ethyl acetate was added in the entire amount. After the polymerization initiator was added, the reaction vessel was continuously charged with ethyl acetate at an addition rate of 17.3 parts/hr while maintaining the internal temperature at 54 to 56℃for 1 hour, and the addition of ethyl acetate was stopped at a point in time when the concentration of the (meth) acrylic resin became 35 mass%, and the reaction vessel was further kept at that temperature until 12 hours passed from the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the (meth) acrylic resin to 20 mass%, and an acrylic resin solution was prepared. The weight average molecular weight Mw of the resulting acrylic resin was 180. Mu.m, and the molecular weight distribution Mw/Mn was 4.2. Mw and Mn were measured by arranging 2 columns of "TSKGEL GMH _HR -H (S)" made by Tosoh Co., ltd. In series in a GPC apparatus, using tetrahydrofuran as an eluent, and measuring the resultant sample by standard polystyrene conversion under conditions of a sample concentration of 2mg/mL, a sample introduction amount of 100. Mu.L, a temperature of 40℃and a flow rate of 1 mL/min.

(6-2) Preparation of adhesive composition

To 80 parts of the solid content of the acrylic resin solution obtained in (6-1), 20 parts (solid content) of a difunctional acrylate (product No. A-DOG, available from Xinzhou chemical industry Co., ltd.), 3.0 parts of a crosslinking agent (product name "Coronate L", manufactured by Tosoh Co., ltd.) (ethyl acetate solution of trimethylolpropane adduct of toluene diisocyanate, solid content concentration 75% by mass), 1.5 parts of a photopolymerization initiator (product name "Irgacure 500", manufactured by Ciba SPECIALTY CHEMICALS Co., ltd.), 0.5 part of a silane coupling agent (product name "KBM-403", manufactured by Xinyu chemical industry Co., ltd.), and ethyl acetate were further added so that the solid content concentration becomes 13% by mass, to obtain an adhesive composition.

[ Chemical formula 11]

(6-3) Production of adhesive sheet

The adhesive composition prepared in (6-2) above was applied to a release treated surface of a release treated separator made of polyethylene terephthalate film (PLR-382150 available from LINTEC Co., ltd.) so that the thickness after drying became 25 μm using an applicator, and dried at 100℃for 1 minute, to prepare an adhesive layer (adhesive sheet). Then, the surface of the obtained pressure-sensitive adhesive layer opposite to the separator was bonded to a release-treated surface of a separator (PLZ-381130, available from LINTEC Co., ltd.) composed of a release-treated polyethylene terephthalate film. Next, the pressure-sensitive adhesive layer was irradiated with ultraviolet rays under the following conditions, thereby producing a pressure-sensitive adhesive sheet.

< UV irradiation conditions >

D Bulb using Fusion UV lamp System (Fusion UV Systems Co., ltd.)

Cumulative light quantity 1500mJ/cm ²

(7) Production of transparent protective film 1

As the transparent protective film 1, as described below, a triacetyl cellulose film (hereinafter, sometimes referred to as "TAC film") having a hard coat layer containing an ultraviolet absorber (hereinafter, sometimes referred to as "NUV-HC layer") as a surface treatment layer was prepared.

(Preparation of surface treatment layer composition)

As a surface treatment layer composition, 20 parts of EBECRYL4858 (DAICEL-ALLNEX, manufactured by Kabushiki Kaisha), 0.80 part of UVA-01 synthesized in Synthesis example 1 below, 0.21 part of Irgacure-184 (manufactured by BASF Japan Co., ltd.), 26 parts of cyclopentanone (manufactured by Kaisha chemical Co., ltd.) and 24 parts of N-methyl-2-pyrrolidone (manufactured by Kaisha chemical Co., ltd.) were mixed, and stirred at room temperature for 2 hours, thereby obtaining a homogeneous solution.

Synthesis example 1

A200 mL-four-necked flask equipped with a Dimu rott (Japanese: high-speed) condenser and a thermometer was put under a nitrogen atmosphere, and 10g of UVA-M-02 powder, 3.7g of acetic anhydride (manufactured by Wako pure chemical industries, ltd.), 5.8g of 2-ethoxyethyl cyanoacetate (manufactured by Tokyo chemical industries, ltd.) and 60g of acetonitrile (manufactured by Wako pure chemical industries, ltd.) which were compounds shown in the following formula, synthesized by reference patent document (Japanese patent application laid-open No. 2014-194508) were put into the flask, and stirred with a magnetic stirrer. 4.7g of N, N-diisopropylethylamine (hereinafter referred to simply as "DIPEA" from Tokyo chemical industries Co., ltd.) was added dropwise from the dropping funnel at an internal temperature of 25℃over 1 hour, and after the completion of the addition, the mixture was further incubated at an internal temperature of 25℃for 2 hours. After the completion of the reaction, acetonitrile was removed by a reduced pressure evaporator, toluene was added to the obtained oil, and the insoluble matter formed was removed by filtration. The filtrate was concentrated again using a reduced pressure evaporator, and the concentrated solution was subjected to column chromatography (silica gel) for purification and recrystallization from toluene, whereby the objective product was obtained. The crystals were dried under reduced pressure at 60℃to thereby obtain 5.2g of the compound UVA-01 as a yellow powder. The yield thereof was found to be 65%. Further, the maximum absorption wavelength (. Lamda.max) of UVA-01 was measured using a spectrophotometer UV-3150 (manufactured by Shimadzu corporation), and as a result,. Lamda.max=389 nm (among 2-butanone), ε (400) was 125L/(g.cm), ε (420)/ε (400) was 0.0153.

Then, by performing ¹ H-NMR analysis, the following peaks were observed, and it was confirmed that the compound UVA-01 was produced.

¹H-NMR（CDCl₃）δ：1.21（t,3H）,2.10（quIn.2H）,2.98-3.04（m,5H）,3.54-3.72（m,6H）,4.31（t,2H）,5.53（d,2H）,7.93（d,2H）

[ Chemical formula 12]

(Formation of surface treatment layer)

The surface treatment layer composition was applied to a triacetylcellulose film having a thickness of 25. Mu.m, using a bar, so that the film thickness after curing became 8. Mu.m, to form a coating film. The formed coating film was irradiated with ultraviolet light in a nitrogen atmosphere (oxygen concentration: 200ppm or less) so that the cumulative light amount became 200mJ/cm ² by passing dry air at 70℃for 30 seconds at a flow rate of 0.5m/s, thereby evaporating the solvent, and then cured, thereby forming a surface-treated layer (NUV-HC layer). The transmittance Tr (450) of light having a wavelength of 450nm of the surface treatment layer (NUV-HC layer) was 90%, the transmittance Tr (420) of light having a wavelength of 420nm was 50%, and the transmittance Tr (400) having a wavelength of 400nm was 0%. Thus, a transparent protective film 1 was obtained as a triacetyl cellulose film having a NUV-HC layer. The thickness of the transparent protective film 1 was 33. Mu.m. The transparent protective film 1 had a 380nm transmittance of 0%.

(8) Fabrication of optical laminate

The retardation film, the polarizing plate 1 and the transparent protective film 1 thus produced were laminated in this order, and the aqueous adhesive was injected between the respective layers in a state where the substrate film side of the retardation film was in contact with the polarizing plate 1 and the opposite side of the polarizing plate 1 was in contact with the TAC film of the transparent protective film 1, and the films were bonded by a nip roll so that the angle between the absorption axis of the polarizing plate 1 and the slow axis of the liquid crystal cured film in the retardation film became 45 °. Then, it was dried at 60℃for 2 minutes. Next, the adhesive layer exposed by peeling one separator from the adhesive sheet produced as described above is laminated on the liquid crystal cured film of the retardation film. Thus, an optical laminate composed of a separator, an adhesive layer, a liquid crystal cured film, a photo-alignment film, a base film, an adhesive layer, a polarizer 1, an adhesive layer, and a transparent protective film 1 was obtained. The total thickness of the optical laminate shown in table 1 is the thickness (from the adhesive layer to the transparent protective film 1) after the thickness of the separator was removed.

Example 2

In the production of the polarizing plate 1, the concentration of the aqueous solution containing iodine and the immersion time of the film in the aqueous solution were adjusted to obtain a polarizing plate 2 having a visibility-correcting monomer transmittance Ty of 42.2% and a thickness of 12 μm. An optical laminate of example 2 was obtained in the same manner as in example 1 except that the polarizing plate 1 was changed to the polarizing plate 2.

Example 3

An optical laminate of example 3 was obtained in the same manner as in example 1 except that the transparent protective film 1 was changed to the following transparent protective film 2. That is, as the transparent protective film 2, a film (manufactured by japan paper corporation, thickness 28 μm,380nm transmittance 3.5%) in which a hard coat layer (hereinafter, sometimes referred to as "HC layer") having a thickness of 3 μm was formed on a stretched film formed of a norbornene-based resin having a thickness of 25 μm was used. The HC layer is formed by the following method.

(Preparation of surface treatment layer composition)

As a surface treatment layer composition, 20 parts of EBECRYL4858 (DAICEL-ALLNEX Co., ltd.), 0.21 part of Irgacure-184 (BASF Japan Co., ltd.), 26 parts of cyclopentanone (Kanto chemical Co., ltd.) and 24 parts of N-methyl-2-pyrrolidone (Kanto chemical Co., ltd.) were mixed and stirred at room temperature for 2 hours, thereby obtaining a homogeneous solution.

(Formation of surface treatment layer)

The surface treatment layer composition was applied to a stretched film of norbornene resin having a thickness of 25 μm using a bar so that the film thickness after curing became 3 μm, thereby forming a coating film. The formed coating film was irradiated with ultraviolet light under a nitrogen atmosphere (oxygen concentration: 200ppm or less) so that the cumulative light amount became 200mJ/cm ² by passing dry air at 70℃for 30 seconds at a flow rate of 0.5m/s, thereby evaporating the solvent, and thereby curing the film, thereby forming a surface-treated layer. The surface treatment layer had a transmittance Tr (450) of light having a wavelength of 450nm of 100%, a transmittance Tr (420) of light having a wavelength of 420nm of 100%, and a transmittance Tr (400) having a wavelength of 400nm of 100%.

Example 4

An optical laminate of example 4 was obtained in the same manner as in example 1 except that the transparent protective film 1 was changed to the following transparent protective film 3. That is, as the transparent protective film 3, a hard coat cyclic olefin resin film (380 nm transmittance 5.3%) having a hard coat layer (HC layer) of 1 μm formed on one surface of a cyclic olefin resin film (COP film) of 13 μm was used. The HC layer of the transparent protective film 3 is formed by the same method as the HC layer of the transparent protective film 2, except that the thickness is changed.

Example 5

An optical laminate of example 5 was obtained in the same manner as in example 1, except that the base film in the phase difference film was changed to the following base film. Specifically, as the base film, a base film obtained by subjecting a triacetyl cellulose film (manufactured by KONICA MINOLTA Co., ltd., thickness: 20 μm) to 1 treatment using a corona treatment device (manufactured by CHUNITICA MOTOR Co., ltd., trade name: AGF-B10) at an output of 0.3kW and a treatment rate of 3 m/min was used. The substrate film had a 380nm transmittance of 91% and a moisture permeability of 1200g/m ².24 hr.

Example 6

An optical laminate of example 6 was obtained in the same manner as in example 1, except that the base film in the phase difference film was changed to the following base film. Specifically, as the base film, a base film obtained by subjecting a triacetyl cellulose film (trade name: FUJITAC TG60UL, thickness 60 μm) to 1 treatment using a corona treatment device (trade name: AGF-B10, manufactured by CHUNYAKO Co., ltd.) under conditions of an output of 0.3kW and a treatment speed of 3 m/min was used. The substrate film had a 380nm transmittance of 91% and a moisture permeability of 500g/m ².24 hr.

Example 7

In the production of the polarizing plate 1, the thickness of the raw film was changed to 60 μm, and the concentration of the aqueous solution containing iodine and the immersion time of the film in the aqueous solution were adjusted to obtain a polarizing plate 3 having a visibility-correcting monomer transmittance Ty of 42.2% and a thickness of 20 μm. An optical laminate of example 7 was obtained in the same manner as in example 1, except that the transparent protective film 1 was changed to the transparent protective film 4 described below and the polarizing plate 1 was changed to the polarizing plate 3. Specifically, as the transparent protective film 4, a triacetyl cellulose (TAC) film (manufactured by KONICA MINOLTA Co., ltd., thickness of 80 μm,380nm transmittance of 1.6%) was used.

Example 8

An optical laminate of example 8 was obtained in the same manner as in example 2, except that the transparent protective film 1 was changed to the following transparent protective film 5 and the thickness of the liquid crystal cured film in the phase difference film was changed to 4.0 μm. Specifically, as the transparent protective film 5, a triacetyl cellulose (TAC) film (40 μm thick, 380nm transmittance 8.0% manufactured by KONICA MINOLTA Co., ltd.) was used. In addition, the value of (S/M)/(S _T/M_T) in the liquid crystal cured film extraction liquid chromatography measurement was 5.5.

Comparative example 1

An optical laminate of comparative example 1 was obtained in the same manner as in example 4, except that ultraviolet irradiation was performed only on the coating film side surface of the laminate composed of the base film, the photo-alignment film, and the coating film containing the polymerizable liquid crystal compound, but not on the base film side surface, in the production of the retardation film. The value of (S/M)/(S _T/M_T) in the liquid-crystal-cured film extraction liquid chromatography measurement was 6.8.

Comparative example 2

An optical laminate of comparative example 2 was obtained in the same manner as in example 8, except that ultraviolet irradiation was performed only from the surface of the laminate including the base film, the photo-alignment film, and the coating film containing the polymerizable liquid crystal compound, but not from the surface of the base film, and the thickness of the liquid crystal cured film in the phase difference film was changed to 2.7 μm in the production of the phase difference film. The value of (S/M)/(S _T/M_T) in the liquid-crystal-cured film extraction liquid chromatography measurement was 6.8.

[ Evaluation ]

The optical laminates produced in examples and comparative examples were evaluated as follows. The evaluation results are shown in table 1.

< Heat resistance >

An evaluation sample was prepared by bonding a surface of the optical laminate on the pressure-sensitive adhesive layer side to alkali-free glass (product number: EAGLE XG (registered trademark), manufactured by Corning Co., ltd.) having a size of 40mm by 40mm and a thickness of 0.7 mm. The sample for evaluation was subjected to a heat resistance test in which the sample was stored at a temperature of 85℃for 250 hours, and the change in-plane retardation (Re (550)) before and after the test was measured by a retardation measuring apparatus (trade name: KOBRA-WPR, manufactured by prince measuring instruments Co., ltd.). Based on the measurement results, evaluation was performed based on the following criteria.

A the change of in-plane phase difference is less than + -4 nm

B, the change of in-plane phase difference is more than +/-4 nm and less than +/-6 nm

C the change of in-plane phase difference is + -6 nm or more

< Light resistance >

An evaluation sample was prepared by bonding a surface of the optical laminate on the pressure-sensitive adhesive layer side to alkali-free glass (product number: EAGLE XG (registered trademark), manufactured by Corning Co., ltd.) having a size of 40mm by 40mm and a thickness of 0.7 mm. The sample for evaluation was put into a solar weather resistance tester (manufactured by Suga Test Instruments corporation) at a temperature of 63 ℃ and a relative humidity of 50% rh for 375 hours, and light resistance test was performed. After the test, the reflectance color (a ^*,b^*) was measured by a spectrocolorimeter (trade name: CM-2600d, manufactured by KONICA MINOLTA Co., ltd.) and a ^*b^* was calculated according to the following formula, and the change of a ^*b^* before and after the test was calculated. The reflectance hue is a value obtained when the light source is D65, and is measured by the SCI method (including specular reflection). In the measurement, the evaluation sample was placed on the aluminum reflecting plate so that the alkali-free glass side corresponds to the aluminum reflecting plate, and light was incident from the evaluation sample side in a state where the layer structure of the aluminum reflecting plate/air/evaluation sample was produced. Based on the measurement results, evaluation was performed based on the following criteria.

a^*b^*＝〔（a^*）²＋（b^*）²〕^1/2

A ^*b^* is less than 0.5

A ^*b^* is 0.5 or more and less than 1.0

A ^*b^* is 1.0 or more and less than 1.5

D a ^*b^* is 1.5 or more

< Reflection tone >

An evaluation sample was prepared by bonding a surface of the optical laminate on the pressure-sensitive adhesive layer side to alkali-free glass (product number: EAGLE XG (registered trademark), manufactured by Corning Co., ltd.) having a size of 40mm by 40mm and a thickness of 0.7 mm. For this sample for evaluation, the reflection color (a ^*,b^*) was measured by a spectrocolorimeter (trade name: CM-2600d, manufactured by KONICA MINOLTA Co., ltd.) and a ^*b^* was calculated according to the following formula. The reflectance hue is a value obtained when the light source is D65, and is measured by the SCI method (including specular reflection). In the measurement, the evaluation sample was placed on the aluminum reflecting plate so that the alkali-free glass side corresponds to the aluminum reflecting plate, and light was incident from the evaluation sample side in a state where the layer structure of the aluminum reflecting plate/air/evaluation sample was produced. Based on the measurement results, evaluation was performed based on the following criteria.

a^*b^*＝〔（a^*）²＋（b^*）²〕^1/2

A ^*b^* is less than 4.0

B: a ^*b^* is 4.0 or more

[ Table 1]

Description of the reference numerals

An adhesive layer, a liquid crystal cured film, a 3 oriented film, a 4 substrate film, a 5 adhesive layer, a polarizing plate, a 7 adhesive layer, a8 protective film, a retardation film comprising a retardation film, optical laminates.

Claims

1. An optical laminate comprising, in order, a protective film, a polarizing plate, a base film, and a liquid crystal cured film,

The thickness of the liquid crystal cured film is more than 2.5 mu m,

The liquid crystal cured film has an extractive liquid chromatography measurement result satisfying the following formula (a):

(S/M)/(S_T/M_T)≤6.4 ...(A)

s, summing peak areas of the liquid crystal monomers;

M, extracting the concentration of the solution;

S _T, toluene peak area;

m _T toluene solution concentration.

2. The optical laminate according to claim 1, wherein the protective film has a 380nm transmittance of 10% or less.

3. The optical laminate according to claim 1, wherein the substrate film has a 380nm transmittance of 50% or more.

4. The optical laminate according to claim 1, wherein the substrate film has a moisture permeability of 50g/m ² -24 hr or more.

5. The optical laminate according to claim 1, wherein the thickness of the base film is 30 μm or more.

6. The optical laminate according to claim 1, wherein the visibility-modifying monomer transmittance Ty of the polarizing plate is 40% or more.

7. The optical laminate according to claim 1, wherein the total thickness of the optical laminate is 150 μm or less,

The thickness of the polarizer is 15 μm or less.

8. The optical laminate according to claim 1, wherein the thickness of the liquid crystal cured film is 3.5 μm or less.

9. A method for producing a liquid crystal cured film, comprising:

A step of forming a liquid crystal cured film having a thickness of 2.5 [ mu ] m or more and satisfying the following formula (A) as a result of measurement by extraction liquid chromatography by irradiating the film with active energy rays from both sides of the film to cure the film,

(S/M)/(S_T/M_T)≤6.4 ...(A)

S, summing peak areas of the liquid crystal monomers;

M, extracting the concentration of the solution;

S _T, toluene peak area;

m _T toluene solution concentration.

10. The method for producing a cured liquid crystal film according to claim 9, wherein the substrate film has a 380nm transmittance of 50% or more.

11. The method for producing a cured liquid crystal film according to claim 9, wherein the substrate film has a moisture permeability of 50g/m ² -24 hr or more.

12. The method for producing a cured liquid crystal film according to claim 9, wherein the thickness of the base film is 30 μm or more.

13. The method for producing a liquid crystal cured film according to claim 9, wherein the thickness of the liquid crystal cured film is 3.5 μm or less.

14. A method for producing an optical laminate comprising a protective film, a polarizing plate, a base film and a liquid crystal cured film in this order,

The method for producing a liquid crystal cured film according to any one of claims 9 to 13, wherein the method for producing a liquid crystal cured film comprises a step of producing the liquid crystal cured film.

15. The method for producing an optical laminate according to claim 14, wherein the protective film has a 380nm transmittance of 10% or less.

16. The method for producing an optical laminate according to claim 14, wherein the visibility-modifying monomer transmittance Ty of the polarizing plate is 40% or more.

17. The method for producing an optical laminate according to claim 14, wherein the total thickness of the optical laminate is 150 μm or less,

The thickness of the polarizer is 15 μm or less.