JP5221531B2 - Optical member made of acrylic block copolymer - Google Patents

Description

  The present invention relates to an optical member made of an acrylic block copolymer. More specifically, the present invention relates to an optical member excellent in flexibility, light resistance, and transparency, formed from a composition containing an acrylic block copolymer excellent in melt processability.

Hitherto, acrylic block copolymers have been studied for various uses because of their excellent characteristics.
For example, Patent Document 1 (Japanese Translation of PCT International Publication No. 2008-508394) and Patent Document 2 (WO 2008/065982) disclose an optical film (heat ray reflective film, polarizing film) having at least one pressure-sensitive adhesive layer made of an acrylic block copolymer. Etc.) are disclosed.

Patent Document 4 (Japanese Patent Application Laid-Open No. 2007-084658) discloses a near-infrared absorbing sheet using a pressure-sensitive adhesive obtained by blending an acrylic block copolymer with a near-infrared absorbing material.
Patent Document 5 (Japanese Patent Laid-Open No. 2003-277574) discloses a transparent and flexible material obtained by blending an acrylic block copolymer and a specific methacrylic resin.

Patent Document 6 (Japanese Patent Laid-Open No. 2003-128809) discloses a laminate film having excellent transparency using an acrylic block copolymer.
Patent Document 7 (Japanese Patent Application Laid-Open No. 11-349782) discloses a covering sheet using an acrylic block copolymer.

Patent Document 8 (Japanese Patent Laid-Open No. 11-302617) discloses a pressure-sensitive adhesive sheet using an acrylic block copolymer.
As a method for producing such an acrylic block copolymer, for example, a living polymerization method using a rare earth compound disclosed in Patent Document 9 (Japanese Patent Application Laid-Open No. 06-93060), Patent Document 10 (Japanese Patent Application Laid-Open No. Hei 5-). No. 507737), a living polymerization method using a mineral acid salt disclosed in JP-A-11-335432, a living polymerization method using an organoaluminum compound disclosed in JP-A-11-335432, and an ATRP disclosed in Non-Patent Document 1. The living polymerization method is known.

  Further, Patent Document 3 (WO2007 / 011017) highly removes residual metal derived from a polymerization initiator of an acrylic block copolymer obtained by anionic polymerization using an organoaluminum compound, and provides high transparency. Is disclosed.

  However, studies on applying an acrylic block copolymer to an optical member in consideration of molding characteristics and physical properties have not been sufficiently performed.

Special table 2008-508394 gazette WO2008 / 065982 Publication WO2007 / 011017 JP 2007-084658 A JP 2003-277574 A JP 2003-128809 A Japanese Patent Application Laid-Open No. 11-349782 Japanese Patent Laid-Open No. 11-302617 Japanese Patent Laid-Open No. 06-93060 Japanese National Patent Publication No. 5-507737 JP-A-11-335432

“Macromol. Chem. Phys.”, 2000, 201, p. 1108 to 1114

  The objective of this invention is providing the optical member excellent in the softness | flexibility, light resistance, and transparency which consists of a material containing the acrylic block copolymer which has the outstanding melt processability.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by an optical member formed from a composition containing a specific acrylic block copolymer. The invention has been completed.

That is, according to the present invention, the above object is
An optical member formed from a composition containing an acrylic block copolymer,
The acrylic block copolymer is
Two or more polymer blocks (A) having a glass transition temperature of 50 ° C. or higher, synthesized from a monomer containing at least one selected from methacrylic acid esters and acrylic acid esters,
An optical member comprising at least one polymer block (B) having a glass transition temperature of 20 ° C. or lower, which is synthesized from a monomer containing at least one selected from methacrylic acid esters and acrylic acid esters. This is achieved by making.

The light transmittance of the composition used for the optical member is preferably 90% or more.
The acrylic block copolymer contained in the composition is preferably synthesized by a living polymerization method.

The tensile elastic modulus at 25 ° C. of the composition is preferably 20 MPa to 2000 MPa.
The shape of the optical member is preferably a film or sheet.

The optical member is preferably in the form of a tube, a column, a cone, or a frustum.
The optical member preferably further has an optical function. An example of the optical function is a phase difference function.

  Moreover, an optical element can be produced by combining the optical member and the LED light emitting unit.

  According to this invention, the optical member excellent in the softness | flexibility, light resistance, and transparency which consists of material which has the outstanding melt processability by taking the said structure is provided.

It is explanatory drawing which shows the plane form and cross-sectional form of the shaping | molding cavity formed in the metal mold | die used in the Example. In the brightness | luminance measurement in an Example, it is plane explanatory drawing of the light guide which shows the measurement point. In the luminance measurement in an Example, it is a decomposition explanatory drawing of the structure in the case of the measurement.

Hereinafter, the present invention will be described in detail.
The acrylic block copolymer used for the optical member of the present invention is composed of 2 polymer blocks (A) synthesized from two or more methacrylic acid esters and acrylic acid ester monomers and having a glass transition temperature of 50 ° C. or higher. It is characterized by having at least one polymer block (B) synthesized from a methacrylic acid ester and an acrylic acid ester monomer and having a glass transition temperature of 20 ° C. or lower. A composition containing such an acrylic block copolymer is excellent in melt processability, and an optical member formed from the composition is excellent in flexibility, light resistance, and transparency.

  Examples of the monomer used for the synthesis of the polymer block (A) include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, and methacrylic acid. Methacrylic acid ester such as cyclohexyl, isobornyl methacrylate, phenyl methacrylate, 2-hydroxyethyl methacrylate, methyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, phenyl acrylate, 2-hydroxyethyl acrylate And acrylic acid esters.

  Among these, from the viewpoint of improving the transparency and heat resistance of the obtained optical member, methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, phenyl methacrylate, 2-methacrylic acid 2- Hydroxyethyl, methyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, phenyl acrylate and 2-hydroxyethyl acrylate are preferred, and methyl methacrylate is more preferred. The polymer block (A) may be synthesized from one of these methacrylic esters and acrylic esters, or may be synthesized from two or more. The acrylic block copolymer contains two or more polymer blocks (A), and these polymer blocks (A) may be the same or different.

  As a monomer used for the synthesis of the polymer block (B), for example, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, Methacrylic acid esters such as 2-ethylhexyl methacrylate, pentadecyl methacrylate, dodecyl methacrylate, phenoxyethyl methacrylate, 2-methoxyethyl methacrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, acrylic N-butyl acid, isobutyl acrylate, sec-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate , Benzyl acrylate, phenoxyethyl acrylate, and the like 2-methoxyethyl acrylate.

  Among these, from the viewpoint of improving the flexibility of the obtained optical member, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, phenoxyethyl acrylate, Acrylic esters such as 2-methoxyethyl acrylate are preferred.

  Among these, n-propyl methacrylate, n-butyl methacrylate, n-hexyl methacrylate, 2-methacrylic acid 2-methacrylic acid are used from the viewpoint of improving the transparency, flexibility, cold resistance, and low temperature characteristics of the obtained optical member. Ethylhexyl, pentadecyl methacrylate, dodecyl methacrylate, phenoxyethyl methacrylate, 2-methoxyethyl methacrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-acrylic acid Preferred are butyl, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, benzyl acrylate, phenoxyethyl acrylate, and 2-methoxyethyl acrylate. Ethyl acrylate, n-propyl acrylate, n-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, benzyl acrylate, phenoxyethyl acrylate, 2-methoxy acrylate More preferred is ethyl. The polymer block (B) may be synthesized from one of these methacrylic acid esters and acrylic acid esters, or may be synthesized from two or more kinds. Moreover, when two or more polymer blocks (B) are contained in the acrylic block copolymer, these polymer blocks (B) may be the same or different.

  As long as the characteristics of the acrylic block copolymer used in the present invention are not impaired, the monomer used for the synthesis of the polymer block (A) and the polymer block (B), and further a methacrylic acid ester having a reactive group Acrylic acid esters may also be used. Examples of the methacrylic acid ester and acrylic acid ester having a reactive group include glycidyl methacrylate, allyl methacrylate, glycidyl acrylate, and allyl acrylate. These monomers are usually used in small amounts, but are preferably 40% by mass or less, more preferably 20% by mass or less, based on the total mass of the monomers used for the synthesis of each polymer block. used.

  In addition, as long as the characteristics of the acrylic block copolymer used in the present invention are not impaired, the monomer used for the synthesis of the polymer block (A) and the polymer block (B) may be another unit as necessary. A monomer may be used in combination.

  Examples of these other monomers include methacrylic acid, acrylic acid, styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, acrylonitrile, methacrylonitrile, ethylene, propylene, isobutene, 1,3- Examples include butadiene, isoprene, octene, vinyl acetate, maleic anhydride, vinyl chloride, and vinylidene chloride. These monomers are usually used in small amounts, but are preferably 40% by mass or less, more preferably 20% by mass or less, based on the total mass of the monomers used for the synthesis of each polymer block. used.

The acrylic block copolymer used in the present invention may have other polymer blocks as required in addition to the polymer block (A) and the polymer block (B).
Examples of other polymer blocks include methacrylic acid, acrylic acid, styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, acrylonitrile, methacrylonitrile, ethylene, propylene, isobutene, and 1,3-butadiene. , Polymer blocks or copolymer blocks synthesized from monomers such as isoprene, octene, vinyl acetate, maleic anhydride, vinyl chloride, vinylidene chloride, polyethylene terephthalate, potylene terephthalate, polylactic acid, polyurethane, polydimethylsiloxane A polymer block made of The polymer block also includes a hydrogenated polymer block synthesized from a monomer containing a diene monomer such as 1,3-butadiene and isoprene.

  The bonding form of the polymer block contained in the acrylic block copolymer of the present invention is not particularly limited, but it may have a form in which the polymer block (A) is bonded to both ends of at least one polymer block (B). From the viewpoints of heat resistance, mechanical strength, surface sticking, and the like of the optical member of the present invention. Examples of the copolymer include a triblock copolymer of polymer block (A) -b-polymer block (B) -b-polymer block (A), polymer block (A) -b-heavy Examples thereof include a tetrablock copolymer of a combined block (B) -b-polymer block (A) -b-polymer block (B). Among these, a triblock copolymer of a polymer block (A) -b-polymer block (B) -b-polymer block (A) is more preferable in terms of easy production and less surface sticking.

The glass transition temperature of the polymer block (A) and polymer block (B) in the present invention is the polymer block (A) and polymer block found in the curve obtained by DSC measurement of the acrylic block copolymer. It is the extrapolation start temperature (Tgi) of the transition region of (B). As a specific measuring method, the method detailed in the item of the following Example is employ | adopted. Based on the curve obtained by the DSC measurement, the acrylic block copolymer used in the present invention requires a plurality of glass transition temperatures derived from the polymer block (A) and the polymer block (B). The glass transition temperature derived from the polymer block (A) and the polymer block (B) is the same as the glass transition temperature of the polymer having the same chemical structure (monomer composition, stereoregularity, etc.) as the respective polymer blocks. Therefore, it can be easily determined which polymer block these glass transition temperatures are derived from. The polymer having the same chemical structure as the polymer block (A) and the polymer block (B) is obtained by analyzing the acrylic block copolymer by ¹ H-NMR, ¹³ C-NMR, etc. It can be easily produced by obtaining the chemical structures such as the monomer composition and stereoregularity of the block (A) and the polymer block (B), and appropriately performing polymerization so that the chemical structures are reproduced.

The molecular weight of the acrylic block copolymer is not particularly limited, but from the viewpoint of moldability of the optical member of the present invention, the weight average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC) measurement is 10 000 to 500,000 is preferable, and 20,000 to 300,000 is more preferable.

Examples of the molding method of the optical member of the present invention include a melt extrusion molding method, a melt injection molding method, and a solution casting method. In any molding method, the weight average molecular weight in the above range is determined from the fluidity during molding. Is preferred.

The molecular weight distribution of the acrylic block copolymer is not particularly limited, but the weight average molecular weight / number average molecular weight value is 1.0 from the viewpoint of the adhesiveness and transparency of the surface of the optical member of the present invention.
It is preferably 1 to 2.20, and more preferably 1.05 to 1.60. When the molecular weight distribution is larger than the above range, there may be a disadvantage that the high molecular weight is increased and the transparency is impaired, or the low molecular weight component is increased and the surface sticking becomes severe. In addition, when the molecular weight distribution is smaller than the above range, the composition ratio of the low molecular weight component that favorably affects the moldability and the high molecular weight component that favorably contributes to the mechanical properties becomes small. The mechanical properties required for the member may be impaired.

  The acrylic block copolymer may have a functional group such as a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group, or a trimethoxysilyl group in the molecular chain or at the molecular chain end as necessary. .

  Since the optical member of the present invention requires particularly excellent light transmittance depending on the application, the acrylic block copolymer needs to be sufficiently transparent. Therefore, the total light transmittance of the sheet having a thickness of 3 mm obtained from the acrylic block copolymer is preferably 88% or more, and more preferably 90% or more.

  The acrylic block copolymer preferably has the optical characteristics described above. In order to have such optical properties, the acrylic block copolymer is required to have high purity. As a method for producing such a high-purity acrylic block copolymer, a living polymerization method capable of highly controlling the molecular structure is preferable.

  Living polymerization is a method of synthesizing a block copolymer by polymerizing monomers of a polymer block constituting the block copolymer and then polymerizing other monomers before the polymerization is deactivated or stopped. For example, a method of polymerizing an organic rare earth metal complex as a polymerization initiator (see Patent Document 9), an organic alkali metal compound as a polymerization initiator, and a mineral acid salt such as an alkali metal or alkaline earth metal salt. A method of anionic polymerization in the presence (see Patent Document 10), a method of anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound (see Patent Document 11), an atom transfer radical polymerization method (ATRP) (see Non-Patent Document 1).

  Among the above production methods, in the case of anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound, there is little mixing of a homopolymer as a deactivation component because there is little deactivation during polymerization, As a result, the acrylic block copolymer obtained has high transparency. Further, since the polymerization conversion rate of the monomer is high, the residual monomer in the product is small, and the odor is suppressed. Furthermore, when the monomer which comprises a polymer block (A) is a methacrylic acid ester, the molecular structure of the polymer block obtained becomes high syndiotactic, and there exists an effect which improves heat resistance. And because living polymerization is possible under relatively mild temperature conditions, it is possible to reduce the environmental burden (mainly the energy required for the refrigerator to control the polymerization temperature) for industrial production. There is. From the above points, the acrylic block copolymer is preferably produced by a method of anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound.

Examples of the anionic polymerization method in the presence of the above organoaluminum compound include, for example, an organolithium compound and the following general formula (I):
AlR ₁ R ₂ R ₃ (I)
(In the above formula (I), R ₁ , R ₂ and R ₃ are each independently an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, or a substituent. An aryl group which may have a substituent, an aralkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a substituent Represents an optionally substituted N, N-disubstituted amino group or a halogen atom, wherein two selected from R ₁ , R ₂ and R ₃ are bonded to each other and have a substituent; An alkylene group which may have a substituent, an arylene group which may have a substituent, an arylene alkyl group which may have a substituent, an alkylenedioxy group which may have a substituent, and a substituent. An aryleneoxy group that may be present may be formed.)
The compound shown by these is mentioned.

  As the organic alkali metal compound, an organic lithium compound can be preferably used. Examples of the organic lithium compound include methyl lithium, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, isobutyl lithium, t-butyl lithium, n-pentyl lithium, and n-hexyl lithium. Alkyl lithium or alkylene dilithium such as tetramethylene dilithium, pentamethylene dilithium, hexamethylene dilithium; aryl lithium such as phenyl lithium, m-tolyl lithium, p-tolyl lithium, xylyl lithium, lithium naphthalenide, or Aryldilithium; benzyllithium, diphenylmethyllithium, trityllithium, 1,1-diphenyl-3-methylpentyllithium, α-methylstyryllithium, diisopropenylbenzene Aralkyl lithium or aralkyl dilithium such as dilithium produced by the reaction of butyl lithium; lithium amide such as lithium dimethylamide, lithium diethylamide, lithium diisopropylamide; methoxylithium, ethoxylithium, n-propoxylithium, isopropoxylithium, n-butoxy Lithium, sec-butoxylithium, t-butoxylithium, pentyloxylithium, hexyloxylithium, heptyloxylithium, octyloxylithium, phenoxylithium, 4-methylphenoxylithium, benzyloxylithium, 4-methylbenzyloxylithium, etc. An alkoxide etc. are mentioned.

Among the organic alkali metal compounds, t-butyllithium and sec-butyllithium are preferable because of high polymerization initiation efficiency, and sec-butyllithium is more preferable.
Examples of the organoaluminum compound represented by the above formula (I) include trimethylaluminum, triethylaluminum, tri-n-butylaluminum, trisec-butylaluminum, tri-t-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, Trialkylaluminum such as tri-n-octylaluminum, tri-2-ethylhexylaluminum, triphenylaluminum; dimethyl (2,6-di-tert-butylphenoxy) aluminum, dimethyl (2,6-di-tert-butyl-4- Methylphenoxy) aluminum, diethyl (2,6-di-tert-butylphenoxy) aluminum, diethyl (2,6-di-tert-butyl-4-methylphenoxy) aluminum, diisobuty Dialkylphenoxyaluminum such as (2,6-di-tert-butylphenoxy) aluminum, diisobutyl (2,6-di-tert-butyl-4-methylphenoxy) aluminum; methylbis (2,6-di-tert-butylphenoxy) ) Aluminum, methylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, methyl [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, ethylbis (2,6 -Di-tert-butylphenoxy) aluminum, ethylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, ethyl [2,2'-methylenebis (4-methyl-6-tert-butylphenoxy)] Aluminum, isobutyl bis (2,6- Di-tert-butylphenoxy) aluminum, isobutylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, isobutyl [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] Aluminum, n-octylbis (2,6-di-tert-butylphenoxy) aluminum, n-octylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, n-octyl [2,2′-methylenebis (4-Methyl-6-tert-butylphenoxy)] alkyldiphenoxyaluminum such as aluminum; methoxybis (2,6-di-tert-butylphenoxy) aluminum, methoxybis (2,6-di-tert-butyl-4-) Methylphenoxy) aluminum, methoxy [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, ethoxybis (2,6-di-tert-butylphenoxy) aluminum, ethoxybis (2,6-di-tert-butyl-4) -Methylphenoxy) aluminum, ethoxy [2,2'-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, isopropoxybis (2,6-di-tert-butylphenoxy) aluminum, isopropoxybis ( 2,6-di-tert-butyl-4-methylphenoxy) aluminum, isopropoxy [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, tert-butoxybis (2,6-di) -Tert-butylphenoxy) aluminum, te Alkoxydiphenoxy such as rt-butoxybis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, tert-butoxy [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum Aluminum; triphenoxyaluminum such as tris (2,6-di-tert-butyl-4-methylphenoxy) aluminum and tris (2,6-diphenylphenoxy) aluminum.

  Among the organoaluminum compounds described above, isobutyl bis (2,6-di-tert-butylphenoxy) aluminum, isobutyl bis (2,6-di-tert) are preferred from the viewpoint of high living property of polymerization and easy handling. -Butyl-4-methylphenoxy) aluminum and isobutyl [2,2'-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum are preferred.

  In addition to the above organoaluminum compound, if necessary, an ether such as dimethyl ether, dimethoxyethane, diethoxyethane, 12-crown-4; triethylamine, N, N, N ′, N′-tetramethylethylenediamine, N-containing compounds such as N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetramine, pyridine, 2,2′-dipyridyl, etc. The acrylic block copolymer may be polymerized by being present in the reaction system.

  The anionic polymerization is usually performed in the presence of an inert solvent. Examples of the inert solvent include hydrocarbon solvents such as benzene, toluene, and xylene; halogenated hydrocarbon solvents such as chloroform, methylene chloride, and carbon tetrachloride; ether solvents such as tetrahydrofuran and diethyl ether. .

  The method for producing an acrylic block copolymer by anionic polymerization in the presence of an organoaluminum compound is further specifically exemplified. For example, in the presence of an organoaluminum compound, a first step of polymerizing a monomer that forms a polymer block (A) with a polymerization initiator composed of an organic alkali metal compound, a single amount that forms a polymer block (B) The acrylic block copolymer can be produced through three or more polymerization steps including a second step of polymerizing the polymer and a third step of polymerizing the monomer forming the polymer block (A).

  In the said manufacturing method, a desired polymer block will be formed at the living polymer terminal produced | generated at each process at the next process. Therefore, for example, the polymer block (A) -polymer block is obtained by continuously reacting the active terminal of the obtained polymer with alcohol or the like through the above three-stage polymerization process and stopping the polymerization reaction. A ternary block copolymer comprising (B) -polymer block (A) can be produced. Here, the quaternary or more block copolymer is a desired polymer block obtained by polymerizing monomers (polymer block (A), polymer block (B), etc.) in addition to the above three-step process. ) Is added a desired number of times, and the active terminal of the obtained polymer is reacted with an alcohol or the like to stop the polymerization reaction.

  When the composition containing the acrylic block copolymer used in the optical member of the present invention is used as an optical member, it needs an elastic modulus and flexibility that can maintain its form. Therefore, the acrylic block copolymer preferably has a tensile modulus at 25 ° C. of 100 MPa to 2500 MPa, and more preferably 200 MPa to 2000 MPa.

  In order to obtain an acrylic block copolymer having an elastic modulus in the above range, a composition ratio of the polymer block (A) and the polymer block (B) of the acrylic block copolymer (polymer block (A)). / Polymer block (B)) is preferably 20/80 to 70/30, and more preferably 30/70 to 50/50. When the composition ratio of the polymer block (A) / polymer block (B) is smaller than the above range, the adhesion may be severe and the surface property may be impaired due to adhesion of scratches and dust. The shape retainability may be deteriorated and the handleability may be reduced. When the composition ratio of the polymer block (A) / polymer block (B) is larger than the above range, the flexibility of the acrylic block copolymer tends to be insufficient.

  The composition used for the optical member of the present invention contains the acrylic block copolymer as an essential component. Moreover, 1 type of the said acrylic block copolymers may be contained in the said composition, and 2 or more types may be contained.

  Since the said composition is used for the optical member of this invention, it is preferable that the said acrylic block copolymer is fully included in the range which does not impair the effect of this invention. The content of the acrylic block copolymer in the composition is not particularly limited as long as the effect of the present invention is not impaired, but is 30% to 100% by weight with respect to the total weight of the composition. It is preferably 50 wt% to 100 wt%.

  Since the said composition is used as an optical member, it needs the especially outstanding light transmittance depending on a use. Therefore, the total light transmittance of the sheet having a thickness of 3 mm obtained from the composition is preferably 88% or more, and more preferably 90% or more.

  In addition, the suitable light transmittance of the said composition can be suitably set according to the wavelength required by an actual use in the state processed into the optical member. The wavelengths to be measured are typically near infrared (700 to 2,500 nm), mid infrared (2,500 to 4,000 nm), far infrared (4,000 to 1,000,000 nm), visible light (360 to 730 nm). ), Ultraviolet light (10 to 400 nm), far ultraviolet light, laser light, and the like.

  Moreover, when using this composition as an optical member, the elasticity modulus and the softness | flexibility which can hold | maintain the form are needed. Therefore, the composition containing the acrylic block copolymer preferably has a tensile elastic modulus at 25 ° C. of 100 MPa to 2500 MPa, and more preferably 200 MPa to 2000 MPa. When the tensile elastic modulus at 25 ° C. of the composition is larger than the above range, the flexibility is insufficient and the bending workability and the flexibility are inferior. On the other hand, if it is smaller than the above range, sticking or sticking occurs when it is molded as an optical member, which may cause inconvenience in handling depending on the application.

  The elastic modulus of the optical member of the present invention can be appropriately selected according to the application. For example, when the optical member is used in the form of a film, a tube, a rod, etc., the tensile elastic modulus at 25 ° C. can be selected from 500 MPa to 2000 MPa, and in addition to the optical characteristics, the member has cushioning properties and rubber elasticity. When used, the tensile elastic modulus at 25 ° C. can be selected from 100 MPa to 500 MPa. Further, when the optical member of the present invention is used as a sealing member or an adhesive member, the tensile elastic modulus at 25 ° C. can be selected from 10 MPa to 100 MPa.

  Further, the composition includes other polymers such as resins and rubbers, and further softeners, lubricants, plasticizers, adhesives, tackifiers, heat stabilizers, oxidation agents, and the like within a range not impairing the effects of the present invention. Additives such as an inhibitor, a light stabilizer, an antistatic agent, a flame retardant, a foaming agent, a colorant, a dyeing agent and a filler may be contained. One or more of these other polymers and additives may be contained in the composition.

As said other polymer, other acrylic type block copolymers other than the acrylic type block copolymer used by this invention are mentioned, for example.
Examples of the resin include acrylic resins such as polymethyl methacrylate and methacrylate ester copolymers; polyethylene, ethylene-vinyl acetate copolymer, polypropylene, poly 1-butene, poly-4-methyl 1-pentene. Olefin resins such as polynorbornene; ethylene ionomers; polystyrene, styrene-maleic anhydride copolymer, high impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin, MBS resin, and other styrene resins ; Methyl methacrylate-styrene copolymer; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polylactic acid; polyamides such as nylon 6, nylon 66, polyamide elastomer; polycarbonate, polyvinyl chloride, polyethylene Vinylidene chloride, polyvinyl alcohol, ethylene - vinyl alcohol copolymer, polyacetal, polyvinylidene fluoride, polyurethanes, modified polyphenylene ether, polyphenylene sulfide, and the like silicone rubber-modified resins. Among these resins, acrylic resin, ethylene-vinyl acetate copolymer, AS resin, polylactic acid, and polyvinylidene fluoride are preferably used from the viewpoint of compatibility with the acrylic block copolymer contained in the composition.

  Examples of the rubber include acrylic rubber; silicone rubber; styrene TPE (thermoplastic elastomer) such as SEPS, SEBS, and SIS; and olefin rubber such as IR, EPR, and EPDM.

Examples of the softener include mineral oils such as paraffinic oil and naphthenic oil. When these softening agents are contained in the composition, the fluidity during molding is improved.
Examples of the filler include inorganic fibers such as glass fibers and carbon fibers, and organic fibers; inorganic fillers such as calcium carbonate, talc, carbon black, titanium oxide, silica, clay, barium sulfate, and magnesium carbonate. . When inorganic fiber and organic fiber are contained in the composition, a reinforcing effect is imparted to the obtained optical member. When the inorganic filler is contained in the composition, heat resistance and weather resistance are imparted to the obtained optical member.

When the heat stabilizer or the antioxidant is contained in the composition, heat resistance and weather resistance are further improved. Therefore, it is preferable that the composition is practically contained in the composition.
These other polymers and additives may be added when the optical composition is produced by molding the composition.

The optical member of the present invention can be produced by molding the above composition.
The optical member of the present invention can be applied to general optical applications, but is excellent in light resistance and transparency. Therefore, light emitted from a light source is incident on the member, the light is transmitted through the member, and the light is transmitted to the outside of the member. It is suitably used as an optical member that emits light and has a translucent function. Although there is no restriction | limiting in particular as said light source, Sunlight, natural light, an incandescent lamp, a fluorescent lamp, a cold cathode tube, an ultraviolet light, a neon tube, and an organic and inorganic light emitting diode (LED) are mentioned. Since the acrylic block copolymer used in the optical member of the present invention is particularly excellent in light transmittance in the ultraviolet region, it can be particularly suitably used as an optical member of an optical element in which ultraviolet light or LED is a light source.

  Since the composition used for the optical member of the present invention has excellent melt processability, it can be easily molded into various shapes depending on the application. The method for molding the optical member of the present invention is not particularly limited as long as the composition can be molded to produce an optical member having a desired shape.

  Examples of the shape of the optical member include a film shape, a sheet shape, a tube shape, a column shape, a cone shape, and a frustum shape. The tube shape and the column shape may include shapes such as a lot shape and a fiber shape. The film-shaped optical member may also include a member whose main part is a film. The same applies to sheet-shaped, tube-shaped, columnar, conical, and frustum-shaped optical members. Further, the columnar shape, the cone shape, and the frustum shape may include a substantially columnar shape such as a capsule shape and a bullet shape, a substantially cone shape, and a substantially frustum shape. The outside of the optical member typically has the above shape, but the inside may be hollow or solid depending on the application.

When the shape of the optical member of the present invention is a film or a sheet, the optical member can be produced by, for example, a melt extrusion molding method or a solution casting method.
As said melt extrusion molding method, the general method used for manufacture of a film-like or sheet-like member can be used. Specific examples include a method using a die, an inflation method, and the like, but a method using a die is preferable in terms of excellent productivity and thickness accuracy.

  In the case of producing a film-like or sheet-like member by a melt extrusion molding method using a die, for example, the member melts the composition containing an acrylic block copolymer in an extruder, It can be manufactured by extruding into a sheet or film form from a die attached to an extruder and pulling the extruded sheet or film in close contact with at least one cooling drum.

  The die is not particularly limited, and examples thereof include known dies such as a T die and a coat hanger die. Examples of the material of the die include SCM steel and stainless steel such as SUS, but are not limited thereto.

  As said solution casting method, the general method used for manufacture of a film-like or sheet-like member can be used. Specifically, as a support, a heat-resistant material such as polyethylene terephthalate or a flat plate or roll such as a steel belt is used, and on these, the above composition is used using a bar coater, roll coater, die coater, comma coater, or the like. The method of casting the solution which contains it and removing a solvent by drying etc. are mentioned.

  The method for removing the solvent by drying is not particularly limited, and a conventionally known method can be used, but it is preferable to perform drying in a plurality of stages. When drying is performed in a plurality of stages, the first stage of drying is performed at a relatively low temperature in order to suppress foaming due to rapid volatilization of the solvent. In order to remove the solvent, a method of drying at a high temperature is more preferable.

  In the above solution casting method, the solvent used for dissolving the composition containing the acrylic block copolymer is not particularly limited as long as it is a solvent capable of dissolving the composition. For example, toluene, ethyl acetate, ethylbenzene, chloride Examples include methylene, chloroform, THF, methyl ethyl ketone, DMSO, and a toluene-ethanol mixed solvent. Of these, toluene, ethylbenzene, ethyl acetate, and methyl ethyl ketone are preferable.

  The concentration of the solvent in the solution is appropriately determined in consideration of the solubility of the composition in the solvent, the viscosity of the obtained solution, and the like, but a preferred lower limit is 5% by weight and a preferred upper limit is 50% by weight.

When the shape of the optical member of the present invention is a tube shape, a column shape, a cone shape, or a frustum shape, the optical member can be produced by, for example, a melt extrusion molding method or a melt injection molding method.
As the melt extrusion molding method, a general method used for manufacturing a tube-shaped, columnar, conical, or frustum-shaped member can be used.

  Specifically, for example, a tube-shaped, columnar, conical, or frustum-shaped member can be manufactured by a melt extrusion method using a die. In the case of producing by the melt extrusion molding method, for example, the member is a die having a desired shape, which is prepared by melting the composition containing an acrylic block copolymer in an extruder, and attached to the extruder. Then, a tube-shaped member, a columnar member, a pyramid member, or a frustum-shaped member can be manufactured by extruding in a desired shape and cutting as necessary.

As the melt injection molding method, a general method used for manufacturing a tube-shaped, columnar, conical, or frustum-shaped member can be used.
Specifically, for example, the above composition containing an acrylic block copolymer is melted in an injection molding machine, and the melted composition is injected into a mold having a desired shape. it can.

  The shape of the optical member of the present invention is typically a sheet shape, a film shape, a tube shape, a column shape, a cone shape, or a frustum shape as described above, but takes other shapes depending on the application. In some cases. When the optical member of the present invention takes other shapes, it is manufactured by a known molding method such as the above-described melt extrusion molding method, melt injection molding method, solution casting method, or a combination of these molding methods. Can do.

  The optical member of the present invention may be provided with a pattern or the like on the surface according to the application. The surface of the optical member may be subjected to surface treatment. Examples of the surface treatment include corona treatment, plasma treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, ion bombardment treatment, heat treatment in vacuum, antifouling treatment, antistatic treatment, and antireflection treatment.

The optical member of the present invention may be provided with a dielectric layer, a transparent conductive layer or the like on the surface thereof.
As the dielectric constituting the dielectric layer, a transparent material is usually used. For example, the dielectric is manufactured using a metal oxide such as Si, Al, Ti, Zr, In, and Sn as a raw material. The metal oxide of these metals may be one kind or two or more kinds. When two or more metals are combined, for example, Zr and Ti, Al and Zr, In and Sn can be used in combination. Such a dielectric layer is usually transparent, but is preferably not colored. The dielectric layer can be produced by physical vapor deposition (PVD) methods such as vapor deposition, sputtering, and ion plating, and vapor deposition, particularly electron beam vapor deposition, is preferred in terms of productivity.

  The transparent conductive layer is manufactured using, for example, a metal such as Sn, In, Ti, Pb, Au, Pt, or Ag, or an oxide thereof, or carbon or carbon nanotube. For example, a transparent conductive layer can be produced by forming a single metal layer on the surface of the optical member and oxidizing the single metal layer as necessary. Alternatively, the transparent oxide layer may be produced by attaching these metal oxides themselves to the surface of the optical member. Furthermore, the layer may be formed in the form of a single metal layer or a lower oxide layer at the beginning of the layer formation, and then subjected to an oxidation treatment such as heat oxidation, anodization or liquid phase oxidation to produce a transparent conductive layer. .

  The optical member of the present invention is generally applicable to optical applications, but is excellent in light resistance and transparency, and thus basically excellent in light transmission function. For example, other components may be added to the composition used for the optical member. Further, by imparting a desired shape to the optical member at the time of molding, other optical functions can be added and used. The optical function in the present invention is a function that changes the light incident on the optical member from the light source. For example, the reflection function that reflects at least part of the light, and the light absorption that absorbs at least part of the light. Functions, and a phase difference function that gives a phase difference to incident light.

Since the optical member of the present invention is excellent in flexibility, light resistance, and transparency, it can be used in various applications.
When the shape of the optical member of the present invention is a film or sheet, examples of the optical member include a polarizing film, a polarizing plate, a retardation film, a viewing angle widening film, a brightness enhancement film, an antireflection film, and an antiglare. Examples include films, color filters, light guide plates, light diffusion films, transflective films, prism sheets, electromagnetic wave shielding films, near-infrared absorbing films, UV nanoimprint masters, and functional composite optical films that combine multiple optical functions. It is done.

A film made of a thermoplastic resin used in a device that handles polarized light such as a liquid crystal display device is required to have optical homogeneity in addition to being optically transparent and having low birefringence. For this reason, in the case of a polarizer protective film of a polarizing plate, a film substrate for a plastic liquid crystal display device in which the glass substrate is replaced with a resin film, etc., the phase difference represented by the product of birefringence and thickness is small, or external It is required that the phase difference of the film hardly changes due to stress or deformation. That is, if the phase difference is large or the phase difference changes due to external stress or deformation, there arises a problem that the image quality of the liquid crystal display device is remarkably lowered. For example, color skipping phenomenon such as partial color fading, and adverse effects such as image distortion occur.The optical member of the present invention is excellent in transparency and flexible, has a small phase difference, and has an external property. Since the phase difference of the film hardly changes due to stress or deformation, it is excellent in optical homogeneity, and should be suitably used for an optical member for a liquid crystal display device, particularly a flexible display used by bending the display under stress. it can.

  Furthermore, a retardation film can be produced by imparting a retardation function to the optical member of the present invention by performing a stretching treatment or the like. A specific method for the stretching treatment is not particularly limited, and a conventionally known method can be used. For example, a stretching treatment method such as uniaxial stretching, simultaneous biaxial stretching, and sequential biaxial stretching can be used.

  The retardation film has a characteristic that the retardation of the film hardly changes due to external stress or deformation, and therefore the retardation function hardly changes due to external stress or deformation. Therefore, the retardation film can be suitably used for a liquid crystal display device. . In particular, it can be suitably used for an optical member for a flexible display that is used by bending the display with stress.

  Moreover, as an optical member of the present invention, a retardation film produced by using a stretching method can be used by laminating on a polarizing plate with an adhesive, or by directly bonding to a polarizer, the retardation film function. It can also be used as a polarizer protective film.

  What is necessary is just to adjust the retardation of the said retardation film suitably according to a use. For example, when used in a twisted nematic (TN) liquid crystal display device, it is usually about 20 to 300 nm, and when used in a super twisted nematic (STN) liquid crystal display device, it is usually about 150 to 2000 nm. When used in a vertical aligned (VA) liquid crystal display device, it is usually about 0 to 200 nm, and when used for an optically compensated bend (OCB) liquid crystal display device, it is usually about 20 to 200 nm. The retardation film can also be used as a λ / 4 plate or a λ / 2 plate used for a composite polarizing plate such as a circularly polarizing plate or an elliptically polarizing plate. When used as a λ / 4 plate, the retardation of the film is usually about 100 to 200 nm, and when used as a λ / 2 plate, the retardation of the film is about 200 to 300 nm.

The ratio (R ₄₀ / R ₄₀ ) of the retardation (R ₄₀ ) when tilted by 40 ° from the vertical direction with the slow axis as the tilt axis, relative to the retardation (R ₀ ) measured from the direction perpendicular to the plane of the retardation film. R ₀ ) may be adjusted as appropriate according to the application. For example, when used in a TN liquid crystal display device, the ratio (R ₄₀ / R ₀ ) is usually about 0.9 to 1.5, which is a λ / 4 plate or a λ / 2 plate used for a composite polarizing plate. In some cases, the ratio (R ₄₀ / R ₀ ) is usually about 0.9 to 1.5, and when used in an STN liquid crystal display device, the ratio (R ₄₀ / R ₀ ) is usually 0.9. It is about -1.1. Further, when used in a VA liquid crystal display device and an OBC liquid crystal display device, the ratio (R ₄₀ / R ₀ ) is usually 1.0 or more, and there is no particular upper limit, and R ₀ may be 0. . The thickness of the retardation film may be appropriately adjusted according to the use, but is usually about 30 to 300 μm.

  When the optical member of the present invention is used as a brightness enhancement film, for example, a film in which particles are dispersed so that the reflectance anisotropy is caused by the refractive index anisotropy, and the reflectance based on the difference in scattering ability depending on the size What is necessary is just to produce the film etc. which the inorganic particle disperse | distributed so that anisotropy may arise.

  When the optical member of the present invention is used as a light diffusing film, the light diffusing film is added, for example, to the composition with a light diffusing agent having a refractive index different from that of the composition used for the optical member. And it can manufacture by shape | molding this into a film.

  The difference between the refractive index of the light diffusing agent: nD (c) and the refractive index of the composition: nD (a): ΔnD (= | nD (c) −nD (a) |) is preferably 0. 0.005 or more, more preferably 0.01 or more. Further, ΔnD is preferably 0.3 or less. If this refractive index difference: ΔnD exceeds 0.3, the total light transmittance tends to decrease, and if it is less than the above value, the diffusivity tends to decrease. The light diffusing agent is transparent, and is not particularly limited as long as the refractive index condition is satisfied. From the viewpoint of obtaining a more excellent light diffusing effect, transparent particles are preferably used. Examples of the transparent particles include various inorganic particles and organic particles.

  Examples of the inorganic particles include silica particles, alumina particles, silica alumina particles, talc, barium carbonate particles, and metal particles. Examples of the organic particles include silicone resin particles, acrylic resin particles, nylon resin particles, urethane resin particles, styrene resin particles, polyethylene resin particles, and polyester resin particles. As the transparent particles, a thin film made of a metal oxide such as silicon oxide, zinc oxide, titanium oxide or zirconium oxide, or a metal fluoride such as MgF2 is formed on the surface of the core of glass, metal or synthetic resin. Particles can also be used.

  Although the particle size of these particles is not particularly limited, the average particle size is usually about 0.5 μm to 30 μm, preferably 1 μm to 20 μm, more preferably 1 μm to 15 μm. When the average particle size is smaller than the above range, the light diffusibility increases, but the light transmittance tends to decrease. When the average particle size is larger than the above range, the light transmittance increases, but the light diffusibility increases. It tends to decrease and uneven brightness tends to occur.

  The shape of the transparent particles preferably used as the light diffusing agent is preferably spherical. When spherical particles are used as the light diffusing agent, such spherical particles act as a kind of lens, and a more effective light diffusion effect is obtained. Here, the term “spherical” refers to a shape having a short axis / major axis ratio of fine particles of preferably 0.6 or more, more preferably 0.8 or more, particularly preferably 0.9 or more, and having no corners. The short diameter means the smallest diameter of one particle, and the long diameter means the largest diameter of the same particle. The ratio of the spherical particles contained in the transparent particles used here is preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more. Moreover, what is necessary is just to measure based on the image | video of a micrograph about the short diameter of a particle, a long diameter, the presence or absence of an angle | corner, and an average particle diameter. When there are many non-spherical particles, it becomes difficult to obtain a uniform light-diffusible molded product having non-uniform dispersion during molding or having orientation. In addition, the light-diffusion agent used for a light-diffusion film may be single 1 type, and may use multiple types together.

The light transmittance and light diffusibility of the light diffusing film can be adjusted, for example, by adding a plurality of light diffusing agents to the composition in an appropriate blending amount.
When the optical member of the present invention is used as a transflective film, the transflective film is formed, for example, by dispersing pearl mica particles or the like in the composition used for the optical member of the present invention and molding the film into a film. Can be produced.

  When the optical member of the present invention is used as an electromagnetic shielding film, a method of laminating a transparent conductive film on at least one surface of the film, a method of laminating a conductive network on at least one surface of the film, or a film An electromagnetic wave shielding film can be produced by, for example, a method in which a conductive network is embedded and laminated and integrated.

  The transparent conductive film is coated with a resin solution in which conductive fine particles such as metal fine particles and metal oxide fine particles are dispersed, for example, by vacuum deposition or sputtering of metal, metal oxide, or the like. Can be produced. Examples of the metal include gold, silver, platinum, palladium, copper, titanium, chromium, molybdenum, nickel, and zirconium. Among these, silver is preferable in that a conductive layer having excellent conductivity can be easily obtained. When this metal layer is provided as a conductive layer, it is preferably a multilayer film with a dielectric layer in order to prevent reflection of the metal layer. Examples of the dielectric layer include layers made of various metal oxides, metal nitrides, metal sulfides, and the like. Examples of the metal oxide include silicon oxide, titanium oxide, tantalum oxide, tin oxide, indium oxide, zirconium oxide, zinc oxide, and a composite oxide of indium oxide and tin oxide.

Of these metals and metal oxides, one of them may be used alone, or two or more of them may be used in combination.
Examples of the method for laminating the conductive network include, for example, a method of laminating a metal mesh or a resin conductive mesh coated with a metal layer on the surface, or using a conductive ink or the like on the surface of a transparent resin plate. Examples thereof include a method of printing a grid pattern, or a method of forming a grid pattern by means such as etching after providing a metal thin film such as copper or aluminum on the film surface.

  Examples of the fibers constituting the conductive mesh include synthetic fibers such as polyester having a surface coated with a metal layer such as copper fiber, stainless steel fiber, gold, silver, and copper. The diameter of the fiber constituting the mesh of the conductive mesh is usually 10 to 60 μm, and the mesh size is preferably in the range of 40 to 200 mesh. The mesh size is a size defined by a Tyler standard sieve. In order to prevent metallic luster, such a conductive mesh may be colored black with a conductive paint or plating on its surface.

The electromagnetic wave shielding film thus obtained can be used for shielding electromagnetic waves emitted from the front surface of the plasma display, for example.
When the optical member of the present invention is used as a near-infrared absorbing film, a near-infrared absorbing dye, typically a diimonium-based near-infrared absorber, an aminium-based near-infrared absorber, an anthraquinone-based near-infrared absorber, phthalocyanine Near infrared absorber, especially fluorine-containing phthalocyanine near infrared absorber, nickel complex near infrared absorber, polymethine near infrared absorber, diphenylmethane near infrared absorber, triphenylmethane near infrared absorber, cyanine near A near-infrared absorbing dye that has a high transmittance with respect to visible light such as an infrared absorbent and absorbs a large amount of light in the near-infrared region is dispersed in the composition used for the optical member of the present invention, and this is formed into a film. Can be produced.

  The near-infrared absorbing film thus obtained can be used, for example, to block near-infrared rays emitted from the emission of inert gas in the plasma display cell.

  The optical member of the present invention can be used as a light guide plate. The shape of the light guide plate is basically a sheet shape or a film shape, but may be a block shape, a rod shape, a bent shape, a curved shape, or other known shapes. The light guide plate may be provided with dots by screen printing on at least one surface thereof, and a linear pattern such as a V-groove, a hemispherical lens-like unevenness, or a texture pattern is applied to the surface of the light guide plate. You may mold. The thickness of the light guide plate may be appropriately adjusted according to the application, but is usually 0.01 mm to 10 mm from the viewpoint of securing practical moldability and strength and from the viewpoint of weight reduction.

  Further, the light guide plate may be subjected to a light reflection process, a light diffusion process, or a light collection process on at least one surface thereof. In addition, what is necessary is just to perform these light reflection processes, a light-diffusion process, and a condensing process by a well-known method. Generally, light reflection processing is performed on one surface of the light guide plate, and light diffusion processing and light collection processing are performed on the surface opposite to the surface subjected to the light reflection processing. The light reflection process, the light diffusion process, or the light collection process may be performed by adhering the light reflection sheet, the light diffusion sheet, or the light collection sheet to the surface of the light guide plate.

  In addition, although the said light-guide plate can be manufactured by the above-mentioned melt extrusion molding method, it can be manufactured by well-known methods, such as a melt injection molding method, a hot press molding method, and a cutting method. Among these, the melt extrusion molding method, the melt injection molding method, and the hot press molding method are preferable from the viewpoint of productivity.

  When a light source, a light diffusion sheet, a light reflection sheet, and a transmissive display element are combined with the light guide plate thus obtained, an image display device can be manufactured. In the image display, typically, the light source is disposed so as to face the side end surface of the light guide plate, the light reflecting sheet is disposed on one surface side of the light guide plate, and the light is disposed on the opposite surface. A diffusion sheet is arranged. A transmissive display element is disposed in front of the light exit surface of the light guide plate on which the light diffusion sheet is disposed. With such an arrangement, the light from the light source is guided into the light guide from the side end face of the light guide, and the light that has passed through the light guide is effectively diffused by the light diffusion sheet to be emitted and transmitted. The type display element is irradiated with the light. A typical example of the transmissive display element is a liquid crystal panel. Examples of such an image display device include a television and a personal computer monitor. The light guide can also be used for an optical element such as an image display device having another configuration.

  When the shape of the optical member of the present invention is a tube shape, a column shape, a cone shape, or a frustum shape, examples of the optical member include an optical fiber used for a light guide, a photoelectric sensor, and the like.

  When the optical member of the present invention is used as an optical fiber, the composition used for the optical member of the present invention can be melted and spun from a nozzle, and if necessary, drawn by a take-up roller or the like. Further, when the composition used as the optical member of the present invention is used as one layer of an optical fiber, the nozzle can be replaced with a nozzle for composite spinning, and it can be produced by spinning similarly with other molten resin. .

The surface of the optical fiber thus obtained can be further coated with a coating material and used as a normal plastic optical fiber.
In addition, for example, the obtained optical fiber can be used as a light guide in which a light source such as an LED is disposed at the end of the optical fiber and a surface of the optical fiber is caused to emit light without providing a coating layer. Since the optical member of the present invention is rich in flexibility, it is also possible to bend and arrange the optical fiber. For example, the optical fiber and the light source can be replaced with a light bulb or a fluorescent lamp used for an internal display device such as a traffic sign. Can be efficiently used as a light emitting device comprising:

  In addition, the optical member of the present invention can be used as a microlens, a lens sheet, or the like. When the optical member of the present invention is used as a lens sheet or a sheet-like macro lens, for example, a sheet is produced from the composition used for the optical member of the present invention by a melt extrusion method, and the shape of the lens. It can be produced by hot pressing using a press plate in which is engraved.

  The optical member of the present invention is particularly excellent in light transmittance in the ultraviolet region. Therefore, it can be particularly suitably used as an optical member of an optical element using an LED as a light source. Examples of such an optical member include an LED lamp cover and an LED display member in addition to the LED light guide described above.

  In addition, the optical member of the present invention can be used for all other optical applications regardless of the shape and the like, utilizing its excellent flexibility, light resistance, and transparency. For example, various mobile communication keys for mobile phones, illuminated keys used as electronic notebooks and other terminal keys, touch panels, VDT filters, PDP front plates, projection TV front plates, CRT image display plates, optical types Cover materials such as disks, auxiliary lamps for automobiles, headlamps, tail lamps, display members provided on side mirrors for automobiles, members for instrument panels for automobiles, sun visors, members for light emitting room mirrors, glasses, sunglasses, cameras, telescopes It can be used for lenses, prisms, mirrors, lighting plates, signboards, window glass, lighting fixtures, etc. used in microscopes and projection televisions.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Various physical properties in Examples and Comparative Examples were measured or evaluated by the following methods.
(1) Weight average molecular weight (Mw)
The weight average molecular weight (Mw) of the acrylic block copolymer and acrylic resin was determined by gel permeation chromatography (hereinafter abbreviated as GPC) in terms of polystyrene equivalent molecular weight.
-Equipment: GPC equipment "HLC-8020" manufactured by Tosoh Corporation
Separation column: “TSKgel GMHXL”, “G4000HXL” and “G5000HXL” manufactured by Tosoh Corporation are connected in series. Eluent: Tetrahydrofuran Eluent flow rate: 1.0 ml / min Column temperature: 40 ° C.
・ Detection method: Differential refractive index (RI)
(2) Composition ratio of each polymer block The composition ratio of each polymer block in the acrylic polymer block was determined by ¹ H-NMR ( ¹ H-nuclear magnetic resonance) measurement.
・ Device: JEOL Nuclear Magnetic Resonance Device “JNM-LA400”
Deuterated solvent: deuterated chloroform (3) Glass transition temperature (Tg) of each polymer block
In the curve obtained by DSC measurement using a Mettler DSC measuring device (DSC-822) at a temperature rising rate of 10 ° C./min, the extrapolation start temperature (Tgi) is the glass transition temperature (Tg). ).
(4) Transparency Using the composition containing the acrylic block copolymer obtained in the following examples or comparative examples, the length of the cylinder is 5 cm and the width is 5 cm at a predetermined cylinder temperature and mold temperature by an injection molding machine. A molded body having a thickness of 3 mm was prepared, and the haze value was measured according to JISK7136 and the total light transmittance was measured according to JISK7361 by a direct reading haze meter (manufactured by Nippon Denshoku).
(5) Flexibility (tensile modulus)
Using a composition containing an acrylic block copolymer obtained in the following examples or comparative examples, a test piece having a thickness of 1 mm molded at a predetermined temperature by a press molding machine is created, and tensile dynamic viscoelasticity is measured. The value of elastic modulus (E ′) at 25 ° C. was measured.
・ Device: Wide-range dynamic viscoelasticity measuring device (forced vibration non-resonance method)
"PVE-V4 FT Rheospectr" manufactured by Rheology Co., Ltd.
・ Measurement frequency: 11Hz
・ Measurement mode: Pull ・ Measurement temperature: 25 ℃
-Strain: 0.03%
Sample shape: strip shape (press sheet) of length 20mm x width 5mm x thickness 1mm
(6) Bending resistance (film)
Using a composition containing an acrylic block copolymer obtained in the following examples or comparative examples, a sheet-like molding having a thickness of 0.1 mm was molded at a cylinder temperature and a die temperature of 220 ° C. by a T-die extruder. Using the body, the presence or absence of cracks when bent was evaluated. AA: No crack, crack: cracked.
(7) Punchability (film)
Using a composition containing an acrylic block copolymer obtained in the following examples or comparative examples, a sheet-like molding having a thickness of 0.1 mm molded at a predetermined cylinder temperature and die temperature by a T-die extruder When the test piece was punched from the body with a JIS No. 3 punching blade, the state of punching was observed. AA: Good punchability, cracking: Cracking occurs in the test piece.
(8) Light guiding performance Using a composition containing an acrylic block copolymer obtained in the following examples or comparative examples, a molding test piece was prepared using an injection molding machine NADEM5000 manufactured by Meiki Seisakusho Co., Ltd. Created. As shown in FIG. 1, the test piece is in the shape of a flat light guide having a longitudinal dimension of 200 mm × a lateral dimension of 270 mm and a plate thickness of 4.0 mm. This mold is provided with a gate portion having a width of 40 mm and a thickness of 3.8 mm in the center of the horizontal side. Moreover, the gate part of the obtained light guide was cut with a heat nipper or a saw blade to obtain a test piece. The molding conditions were a resin temperature of 250 ° C., a mold temperature of 60 ° C., an injection time of 4 sec, a holding pressure of 300 MPa, a holding pressure time of 10 sec, and a cooling time of 60 sec.

On the obtained molded product, a reflective pattern layer was printed by screen printing, and the brightness thereof was measured using a color luminance meter: BM-7 manufactured by Topcon Corporation, as shown in FIG. 9 points of brightness were measured from a position of 2 ° visual field and a height of 50 cm, and average brightness and uniformity (9 points minimum brightness / maximum brightness) were evaluated. As shown in FIG. 3, the measurement is performed by arranging two light sources, using a cold-cathode tube luminance of 37000 cd / m ² , as a diffusion sheet, ^two sheets of D124 (manufactured by Tsujiden Co., Ltd.) or as a reflection sheet This was performed using one E60L (Toray Industries, Inc.).

In the synthesis examples shown below, the compound was dried and purified by a conventional method and degassed with nitrogen. Moreover, the transfer and supply of the compounds were performed in a nitrogen atmosphere.
[Reference Example 1] [Organic Aluminum Compound: Preparation of Isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum]
After drying with sodium, 25 ml of dry toluene obtained by distillation under an argon atmosphere and 11 g of 2,6-di-t-butyl-4-methylphenol were placed in a 200 ml flask whose internal atmosphere was replaced with argon. Added and dissolved with stirring at room temperature. To the obtained solution, 6.8 ml of triisobutylaluminum was added and stirred at 80 ° C. for about 18 hours, whereby the corresponding organoaluminum compound [isobutylbis (2,6-di-t-butyl-4-methylphenoxy)] was obtained. A toluene solution containing [aluminum] at a concentration of 0.6 mol / l was prepared.

[Reference Example 2] [Synthesis of acrylic block copolymer (A1)]
A two-liter three-necked flask was fitted with a three-way cock, and the inside was deaerated and replaced with nitrogen. Then, at room temperature, 1040 g of dry toluene, 100 g of 1,2-dimethoxyethane, and isobutylbis (2,6-di-) of Reference Example 1 were used. 48 g of a toluene solution containing 32 mmol of (t-butyl-4-methylphenoxy) aluminum was added, and 8.1 mmol of sec-butyllithium was further added. To this, 72 g of methyl methacrylate was added and reacted at room temperature for 1 hour, and then 0.1 g of the reaction solution was collected. This is designated as sampling sample 1. Subsequently, the internal temperature of the polymerization solution was cooled to −25 ° C., and 307 g of n-butyl acrylate was added dropwise over 2 hours. After completion of dropping, 0.1 g of the reaction solution was collected. This is designated as sampling sample 2. Subsequently, 72 g of methyl methacrylate was added, and the reaction solution was returned to room temperature and stirred for 8 hours. The polymerization was stopped by adding 4 g of methanol to the reaction solution. The reaction solution after termination of the polymerization was poured into a large amount of methanol to obtain a deposited precipitate. This is designated as sampling sample 3. ¹ H-NMR measurement and GPC measurement were performed using sampling samples 1 to 3, and based on the results, Mw (weight average molecular weight), Mw / Mn (molecular weight distribution), methyl methacrylate polymer (PMMA) block and When the mass ratio of the n-butyl acrylate polymer (PnBA) block and the like were determined, the finally obtained precipitate was a PMMA block-PnBA block-PMMA block triblock copolymer (PMMA-b- Mn of the PMMA block part is 9,900, Mw / Mn is 1.08, and Mw of the entire triblock copolymer is 62,000, Mw / Mn is PnBA-b-PMMA) The ratio of each polymer block was PMMA (16% by mass) -PnBA (68% by mass) -PMMA (16% by mass).

[Reference Example 3] [Synthesis of acrylic block copolymer (A2)]
The same operation as in Reference Example 2 was performed to synthesize triblock copolymers (A2) having different molecular weights and copolymer composition ratios. Mw of the whole triblock copolymer obtained was 62,000, Mw / Mn was 1.11, and the proportion of PMMA block in the triblock copolymer was 50% by mass.

[Reference Example 4] [Synthesis of acrylic block copolymer (A3)]
The same operation as in Reference Example 2 was performed to synthesize triblock copolymers (A3) having different molecular weights and copolymer composition ratios. Mw of the obtained triblock copolymer as a whole was 118,000, Mw / Mn was 1.20, and the proportion of PMMA block in the triblock copolymer was 23.0% by mass.

[Examples 1 to 5 and Comparative Examples 1 and 2]
Evaluation was performed under the conditions (4) to (8) above using the acrylic block copolymers (A1) to (A3) prepared in Reference Examples 2 to 4 and the following resins. The results are shown in Table 1 below.
PMMA resin (1): Parapet GF, Kuraray Co., Ltd. PMMA resin (2): Parapet GH-1000S, Kuraray Co., Ltd. non-yellowing TPU resin: XN-2002, Nippon Polyurethane Industry Co., Ltd. In Nos. 4 and 5, the pellets of the thermoplastic polymer composition were produced by melting and kneading at 230 ° C. with a twin screw extruder at the blending ratio shown in Table 1 below, followed by extrusion and cutting. Evaluation was performed using the pellets under the above conditions.

  From the results of Table 1 above, as shown in Examples 1 to 3, the optical member using the acrylic block copolymer is excellent in transparency and light guiding performance, and has excellent flexibility and flexibility. It can be seen that it has a performance compatible with punchability. Moreover, it turns out that the optical member using the some acrylic block copolymer shows the outstanding light guide performance as shown in Example 4. FIG. Furthermore, as shown in Example 5, transparency is not impaired even in an optical member obtained from a composition of an acrylic block copolymer and a PMMA resin. On the other hand, the optical member obtained from the PMMA resin (2) of Comparative Example 1 shows excellent light guiding performance, but is hard because it does not contain the acrylic block copolymer, and has excellent bending resistance and impact resistance. Inferior pullability. In addition, the optical member obtained from the non-yellowing TPU resin of Comparative Example 2 is excellent in bending resistance and punching properties, but has insufficient transparency, particularly light guiding performance.

a: Cold cathode tube b: Reflective sheet c: Diffusion sheet d: Light guide

Claims (4)

An optical member formed from a composition containing an acrylic block copolymer,
The acrylic block copolymer is
Two or more polymer blocks (A) having a glass transition temperature of 50 ° C. or higher, synthesized from a monomer containing at least one selected from methacrylic acid esters and acrylic acid esters,
Retardation function characterized by having at least one polymer block (B) having a glass transition temperature of 20 ° C. or lower, synthesized from a monomer containing at least one selected from methacrylic acid esters and acrylic acid esters An optical member having 2. The optical member having a retardation function according to claim 1, wherein the composition has a light transmittance of 90% or more. The optical member having a retardation function according to claim 1 or 2, wherein the acrylic block copolymer is synthesized by a living polymerization method. 4. The optical member having a retardation function according to claim 1, wherein the composition has a tensile elastic modulus at 25 ° C. of 20 MPa to 2000 MPa.

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