JP2011180461A - Plastic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic lens having high impact resistance although the lens has a photochromic film. <P>SOLUTION: The plastic lens comprises: a meniscus-shaped lens substrate 7 having light-transmitting property in at least a part of the ray region from 200 nm to 420 nm wavelength and having a concave face and a convex face; and a photochromic film 4 formed on the concave face of the lens substrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a plastic lens for spectacles and the like. In particular, the present invention relates to a photochromic lens in which a photochromic film is formed on the lens surface.

  In recent years, plastic photochromic lenses (also referred to as light control lenses) using organic photochromic dyes are commercially available for eyeglasses. They develop colors in bright outdoors and have the same anti-glare effect as high-density color lenses, and recover high transmittance when moving indoors.

  This photochromic function is imparted by forming a film made of a composition containing a photochromic dye on the lens surface. In forming such a photochromic film, it is required to ensure adhesion with the lens substrate and film strength.

For example, in the following Patent Document 1, it is said that the adhesion to the optical substrate and the film strength can be improved by forming a photochromic film with a composition having a specific component and blending ratio.
In particular, an ultraviolet curable photochromic film is formed on the convex surface of the lens, and the optimum film thickness is 10 μm to 50 μm.

As described above, the photochromic film is conventionally provided on the convex surface of the lens. This is because most lens substrates contain an ultraviolet absorber to protect the eyes of the user. Specifically, an ultraviolet absorber that absorbs ultraviolet light having a wavelength shorter than 400 nm is included. The photochromic film exhibits a dimming effect when irradiated with ultraviolet rays. Therefore, if a photochromic film is provided on the back surface (usually concave) of the lens, the ultraviolet light is absorbed by the ultraviolet absorber in the lens substrate, and sufficient ultraviolet light does not reach the photochromic film, making it difficult to obtain a desired dimming action.
For this reason, by providing a photochromic film on the surface on the objective side where ultraviolet rays are not absorbed, it is possible to cause the ultraviolet rays from the outside environment to directly enter the photochromic film and to exert a dimming action according to the outside environment.

JP 2007-77327 A

  A composition for forming a photochromic film is prepared by dissolving a photochromic dye in a matrix. The matrix compatible with the photochromic dye is, for example, an acrylic resin or polyurethane.

These resins are relatively soft and susceptible to physical damage. For this reason, a hard coat layer is formed on the photochromic film to protect the photochromic film.
In addition, an inorganic antireflection film may be provided on the hard coat layer in order to impart an antireflection effect.

  The film quality of such a hard coat layer and antireflection film is very hard. However, when such a hard layer or film is formed on a soft film such as a photochromic film, when a hard object comes into contact with the lens surface, only the upper layer such as a hard coat layer or an antireflection film layer is formed. , Cracked scratches may occur. Thus, even if the photochromic film can be protected, the hard coat layer and the antireflection film itself are easily damaged. For this reason, photochromic lenses have been required to have scratch resistance that is completely different from lenses of other specifications.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a plastic lens having high scratch resistance and impact resistance while having a photochromic film.

In order to solve the above problems, a plastic lens according to the present invention has a meniscus-shaped lens substrate having a light transmitting property in at least a partial region of a wavelength range of 200 nm to 420 nm, a concave surface and a convex surface, and a lens. It includes a photochromic film formed on the concave side of the substrate.
In the present invention, the “lens substrate” includes all of the components existing in the convex surface direction of the photochromic film in the plastic lens.
For example, when a convex antireflection film and a convex hard coat layer are formed on the convex side of a plastic substrate, and a primer layer, photochromic film, concave hard coat layer, and concave antireflection film are formed on the concave side, “Lens substrate” includes a convex antireflection film, a convex hard coat layer, a plastic substrate, and a primer layer.

  According to the plastic lens of the present invention, the photochromic film is formed on the concave surface side of the lens substrate. The lens concave surface is extremely infrequently in contact with an object or receives an impact compared to the convex surface. For example, when the user wears glasses equipped with the lens of the present invention, the photochromic film faces the user's face. Therefore, an impact such as a user's finger touching at the time of wearing is suppressed. Even when the spectacles equipped with the lens of the present invention are not used, the frequency of the external impact on the concave side is extremely low. For this reason, even if a hard coat layer or an antireflection film is formed on the photochromic film, the chances of these layers receiving impact can be reduced.

In particular, the lens substrate preferably has transparency in at least a part of the wavelength range of 200 nm to 420 nm. Furthermore, if a lens substrate having an integrated transmittance of 14% or more is used in the near-ultraviolet region where the wavelength λ is 300 nm or more and 420 nm or less to the visible short wavelength region, a general ultraviolet-sensitive photochromic film is formed on the concave surface side of the lens substrate. Even if it is formed, it is preferable because a sufficient amount of light can be obtained to express a clear dimming action. The most preferable lens substrate has an integrated transmittance of 27% or more in a wavelength region where the wavelength λ is 300 nm or more and 420 nm or less. By forming a photochromic film on the concave surface of such a lens substrate, it is possible to realize a light control effect substantially equivalent to that of a plastic lens having a photochromic film on the convex surface side.
An example of a resin material for a plastic substrate that can easily realize the effect is diethylene glycol bisallyl carbonate.

  In addition, since the lens substrate is transmissive to light in the ultraviolet region as described above, it is possible to irradiate ultraviolet rays from the convex surface side through the lens substrate. For this reason, it is possible to irradiate ultraviolet rays from both the convex and concave surfaces of the lens substrate, and when the photochromic liquid applied on the concave surface of the lens substrate is cured with ultraviolet rays, it is possible to form a film in a short time.

  The photochromic film preferably contains a dye that develops a photoisomerization reaction on the short wavelength side of visible light. The specific wavelength is 420 nm or less, preferably 410 nm or less. Although the light rays having the wavelength in the visible light can be irradiated from sunlight, they are present in a small number in a room or an environment under normal illumination. For this reason, the lens substrate of the present invention is prevented from being colored in the room, but can be colored in the outdoor environment.

  According to the present invention, the photochromic film is provided on the concave surface of the lens that is less likely to come into direct contact with an object or receive an impact. For this reason, the hard coat layer and the antireflection film on the photochromic film are also less susceptible to impact. Therefore, the occurrence of cracks in the hard coat layer and the antireflection film can be suppressed, and a plastic lens that is hardly damaged can be provided.

It is a schematic block diagram (sectional drawing) which shows the structure of the plastic lens which concerns on 1st Embodiment. It is a figure which shows the relationship between the intensity | strength of the light which permeate | transmitted the plastic lens, and the coloring density of the primer layer at that time.

Examples of the best mode for carrying out the present invention will be described below, but the present invention is not limited to the following examples. The description will be made in the following order.
1. 1. Embodiment of plastic lens (1) Lens configuration (2) Plastic substrate (3) Primer layer (4) Photochromic film (5) Hard coat layer (6) Antireflection film Example

1. Embodiment of Plastic Lens (1) Lens Configuration FIG. 1 is a schematic configuration diagram showing an example of a cross-sectional configuration of a plastic lens 100 according to an embodiment of the present invention. In addition, in this figure, the outline of a structure is shown and it does not limit the dimensional ratio etc. of each site | part.
The plastic lens 100 according to the present embodiment has, for example, a meniscus lens shape having a convex surface on one surface and a concave surface on the other surface. When the spectacles using the plastic lens 100 are worn, external light such as ultraviolet rays enters from the convex side of the plastic lens 100 as indicated by an arrow A1.

The plastic lens 100 according to the present embodiment includes, for example, a plastic substrate 1 that refracts incident external light, a hard coat layer 2 formed on the convex surface of the plastic substrate 1, and an antireflection provided on the hard coat layer 2. A membrane 3 is provided.
The plastic lens 100 according to the present embodiment includes a photochromic film 4 provided on the concave surface of the plastic substrate 1 and a hard coat layer 5 formed on the photochromic film 4. The hard coat layers 2 and / or 5 and the antireflection films 3 and / or 6 are not necessarily formed, and other films having other additional functions may be provided.

  The material of the plastic substrate 1 is not particularly limited. However, in the present invention, the plastic substrate 1 is made of a material having ultraviolet transparency, that is, a material such as a light transmissive resin that does not contain an ultraviolet absorber.

  The hard coat layer 2 and the antireflection film 3 are not particularly limited. Moreover, you may interpose the primer layer which is not illustrated between these.

A photochromic film 4 is formed on the concave surface side of the plastic substrate 1. On the photochromic film 4, for example, as shown in FIG. 1, a hard coat layer 5 or an antireflection film 6 may be laminated. If the thickness of the hard coat layer 5 is, for example, about 1 μm to 3 μm, it can function as a protective layer of the photochromic film 4.
In the present invention, since the photochromic film 4 is provided on the concave surface side of the plastic substrate 1, that is, on one side, it is preferably formed by a spin method or a spray method other than the dipping method.
Further, in order to improve the adhesion between the plastic substrate 1 and the photochromic film 4, a primer layer (not shown) may be interposed.

  Thus, the lens substrate 7 in the present embodiment is constituted by, for example, the plastic substrate 1, the hard coat layer 2, the antireflection film 3, the primer layer, and the like. It is preferable that the integrated transmittance in the wavelength region of at least 300 nm to 420 nm is 14% or more with respect to this lens substrate, and the integrated transmittance in the wavelength region of 300 to 410 nm is more than 27%. preferable.

  The concave surface of the plastic lens 100 having a meniscus shape is less likely and less likely to be directly impacted by an object coming into contact with the surface during mounting or storage compared to the convex surface side. In particular, in spectacles, the concave lens surface faces the wearer when worn. Further, since the temples of the glasses are arranged so as to be folded toward the concave surface side of the lens, even if they are dropped, the possibility that an object directly contacts the concave lens surface is significantly lower than that of the convex surface of the lens.

That is, in the plastic lens 100 according to the present embodiment, since the photochromic film 4 is formed on the concave side, it is possible to suppress the photochromic film 4 from being directly impacted by contact with an object.
Further, by forming the photochromic film 4 on the concave side, a soft layer is not arranged under the hard coat layer 2 or the antireflection film 3 on the convex side. For this reason, even if an impact is received on the convex surface side, it is possible to prevent cracks from being generated only in a hard layer such as a hard coat layer or an antireflection film as in the prior art. Therefore, it is possible to provide a lens having high scratch resistance and impact resistance.

Also, the photochromic film may change in color development performance depending on the temperature. However, in the plastic lens 100 according to the present embodiment, since the photochromic film 4 is formed on the concave surface side of the plastic lens 100, it is not easily affected by the external environment.
For example, when the temperature of the photochromic dye reaches a temperature of 35 to 40 degrees, the color development may be reduced and the dimming action may not be exhibited. However, in the air layer on the concave surface side of the spectacle lens during wearing, moisture that diverges from the wearer's eyes or the like and a layer with a temperature more stable than the outside air on the lens convex surface side are formed by not being directly irradiated with light. . For this reason, the change in temperature is small compared to the convex side of the lens, and stable color development performance can be produced.

Conventionally, even if the photochromic film is formed on the concave surface side of the lens substrate, ultraviolet rays are absorbed when the light passes through the lens substrate, and the photochromic film does not exhibit color.
On the other hand, the plastic substrate 1 in the present embodiment is made of a material that does not contain an ultraviolet absorber, or that is adjusted to have a content of the ultraviolet absorber that is less than usual, or a material that transmits ultraviolet rays. Used. Thereby, even if the photochromic film 4 is formed on the concave surface side, it is possible to secure a sufficient amount of light to exhibit a sufficient dimming effect.
Thus, in order to ensure a sufficient amount of light, for example, it is preferable to use a lens substrate having an integrated transmittance of 27% or more from the near ultraviolet region to the visible short wavelength region. As a material of the plastic substrate 1 for realizing this, for example, diethylene glycol bisallyl carbonate (CR39 manufactured by PPG Co., Ltd.) described later can be cited.

  In the present invention, ultraviolet rays that affect the eyes can be absorbed to some extent by the photochromic film 4. For this reason, even if it uses the plastic substrate 1 with an ultraviolet-ray transmittance, eyes can fully be protected. Needless to say, it is possible to add an ultraviolet absorber that absorbs ultraviolet rays having a wavelength shorter than 300 nm or shorter, or an ultraviolet absorber to the extent that the dimming action does not decrease in the range of 300 nm to 400 nm. In order to obtain a dimming effect that does not obstruct the visual field and an ultraviolet absorption effect that protects the eyes, the thickness of the photochromic film 4 is preferably 10 μm or more and 100 μm or less. More preferably, the thickness is 15 μm or more and 50 μm or less.

Next, the material of each part of the plastic lens 100 will be described.
(2) Plastic substrate The material of the plastic substrate used for the plastic lens of this invention will not be specifically limited if it is the material which has the light transmittance in wavelength 300nm -420nm.
For example, diethylene glycol bisallyl carbonate, methyl methacrylate homopolymer, copolymer of methyl methacrylate and one or more other monomers, diethylene glycol bisallyl carbonate homopolymer, diethylene glycol bisallyl carbonate and one or more other monomers Copolymer, sulfur-containing copolymer, halogen copolymer, polycarbonate, polystyrene, polyvinyl chloride, unsaturated polyester, polyethylene terephthalate, polyurethane, polythiourethane, polymer containing epithio group, sulfide Homopolymer of monomer having a bond, copolymer of sulfide and one or more other monomers, copolymer of polysulfide and one or more other monomers, polydisulfide and one or more other monomers Copolymers of over and the like. Moreover, if an ultraviolet absorber that completely absorbs ultraviolet rays of 400 nm or less is added to these lens materials, the light control effect is lowered. For this reason, it is good to use the material which does not add an ultraviolet absorber or is added to the extent which can implement | achieve the transmittance | permeability in the above-mentioned wavelength range.
The surface shape of the substrate was convex or flat on the objective side (surface opposite to the eye for spectacles) and concave on the other side (eye side surface for spectacles). It is preferable to use a so-called meniscus plastic substrate.

(3) Primer layer In addition, a primer layer may be appropriately formed between layers such as a plastic substrate, a photochromic film, a hard coat layer, and an antireflection film as necessary.
The primer layer is not particularly limited as long as it has high adhesion and impact resistance, and when the plastic substrate is made of a relatively high refractive index material, it does not affect the optical properties. For example, polyols, polyisocyanates, NCO group blocking agents of polyisocyanates, and materials containing metal oxides in addition to these can be used.
However, in the case of the present embodiment, as will be described later, providing a photochromic film on the concave surface side of the lens substrate also has a shock-absorbing effect, so it is possible to omit the primer layer for impact resistance formed on the concave surface side of the lens substrate. it can.

  Examples of the polyol include polycarbonate polyol (for example, “Nipporan 980 series (trade name)” manufactured by Nippon Polyurethane Industry Co., Ltd., “carbodiol (trade name)” manufactured by Toagosei Co., Ltd.), and polyether polyol (for example, (stock) ) "ADEKA Polyether (trade name)" manufactured by ADEKA, "ACTCOL PPG-Diol series (trade name)" manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), acrylic polyol (for example, "Takelac (registered trademark)" ) ", DIC (formerly Dainippon Ink and Chemicals, Inc." Acridick (registered trademark) ", etc.), or polyester polyol (DIC Corporation" Polylite (registered trademark) ", Kuraray Co., Ltd.) Kuraray polyol series (trade name) ") and the like can be used.

  Polyisocyanates include polyisocyanate hexamethylene diisocyanate, 1,3,3-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diene. Polyisocyanates such as isocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tetramethylxylylene diisocyanate or their modified products, isocyanurates, allophanates, burettes or carbodiimides, or trimers thereof An adduct body such as a body can be used.

  As a blocking agent for the NCO group of polyisocyanate, β-diketone and methyl ethyl ketoxime are preferable, but acetylacetone, 2,4-hexanedione, 3,5-heptanedione, acetoxime, methyl ethyl ketoxime, caprolactam, and the like can be used. .

  In addition, a metal oxide may be added to such a primer composition in order to increase the refractive index. Examples of the metal oxide include metal oxides composed of one or more metals selected from Si, Al, Sn, Sb, Ta, Ce, La, Fe, Zn, W, Zr, In, and Ti, and further, A sol made of metal oxide fine particles can be used.

In particular, when composed of a material formed by mixing a urethane resin and a rutile type titania sol, it has excellent adhesion and a relatively high refractive index, and the rutile crystalline TiO ₂ has a reduced weather resistance because its photoactivity is suppressed. Has the advantage of being suppressed.
Furthermore, when it comprises from the material formed by mixing a zirconia sol, there exists an advantage that the fall of a weather resistance can be suppressed more.

  Solvents include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, Propylene glycol monobutyl ether acetate, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether Le can be used diethylene glycol dibutyl ether, glycols such as propylene glycol dimethyl ether or propylene glycol diethyl ether.

  As other leveling agents, a copolymer of polyoxyalkylene and polydimethylsiloxane or a copolymer of polyoxyalkylene and fluorocarbon can be used.

(4) Photochromic film The photochromic film is formed by applying and curing a coating liquid having a photochromic dye on a plastic substrate.
A coating liquid can be comprised from a sclerosing | hardenable component (matrix), a photochromic pigment | dye, a polymerization initiator, and the additive added arbitrarily. The method for preparing the coating liquid is not particularly limited, and the coating liquid can be prepared by weighing and mixing a predetermined amount of each component.

  This coating liquid preferably has a viscosity at 25 ° C. of 20 to 500 cp, and more preferably 50 to 300 cp. Furthermore, it is particularly preferably 60 to 200 cp. By setting it as this viscosity range, application | coating of a coating liquid becomes easy and the photochromic film | membrane of desired thickness can be obtained easily.

The curable component that can be used for forming the photochromic film is not particularly limited, and for example, a known curable component having a radical polymerizable group such as a (meth) acryloyl group, a (meth) acryloyloxy group, a vinyl group, an aryl group, or a styryl group. These photopolymerizable monomers and oligomers and their prepolymers can be used. In addition, (meth) acryloyl shows both acryloyl and methacryloyl.
In the case of an acrylic material, UV curing is applied after application, and in the case of a urethane material, a thermosetting treatment is performed to complete a film.
As specific curable components, components described in JP2008-33223A, JP2007-77327A, and the like can be used.

Further, the photochromic dye compound is not particularly limited, and a known one may be used.
Examples thereof include photochromic dye compounds such as fulgimide compounds, spirooxazine compounds, and chromene compounds.

  Other additives include surfactants, antioxidants, radical scavengers, UV stabilizers, UV stabilizers to improve photochromic dye durability, color development speed, fading speed and moldability. Additives such as an absorbent, a release agent, an anti-coloring agent, an antistatic agent, a fluorescent dye, a dye, a pigment, a fragrance, and a plasticizer may be added. As these additives, known compounds can be used without any particular limitation.

(5) Hard Coat Layer A hard coat layer may be provided as a hard film on the surface (convex surface) on which the photochromic film is not provided and the upper surface of the photochromic film.
The material for the hard coat layer is not particularly limited, and a coating liquid comprising a known organosilicon compound and metal oxide colloidal particles can be used. After applying the coating liquid, a hard coat layer can be obtained by a curing treatment.
Examples of the organosilicon compound include an organosilicon compound represented by the following general formula (I) or a hydrolyzate thereof.
(R ⁹¹ ) _{a ′} (R ⁹³ ) _{b ′} Si (OR ⁹² ) _{4- (a ′ + b ′)} (I)
(In the formula, R ⁹¹ is an organic group having a glycidoxy group, an epoxy group, a vinyl group, a methacryloxy group, an acryloxy group, a mercapto group, an amino group, a phenyl group, etc., and R ⁹² is an alkyl having 1 to 4 carbon atoms. Group, an acyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, R ⁹³ is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, and a ′ and b ′ are each 0 or Indicates an integer of 1.)

As said C1-C4 alkyl group of ^R92 , a linear or branched methyl group, an ethyl group, a propyl group, a butyl group etc. are mentioned, for example.
Moreover, as said C1-C4 acyl group of ^R92 , an acetyl group, a propionyl group, an oleyl group, a benzoyl group etc. are mentioned, for example.
Examples of the aryl group having 6 to 10 carbon atoms of R ⁹² include a phenyl group, a xylyl group, and a tolyl group.
Moreover, as a C1-C4 alkyl group of said ^R93 , a linear or branched methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group etc. are mentioned, for example.
And as a C1-C10 aryl group of said ^R93 , a phenyl group, a xylyl group, a tolyl group etc. are mentioned, for example.

Examples of the metal oxide colloidal particles include tungsten oxide (WO ₃ ), zinc oxide (ZnO), silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), and zirconium oxide (ZrO). ₂ ), tin oxide (SnO ₂ ), beryllium oxide (BeO), antimony oxide (Sb ₂ O ₅ ) and the like, and may be used alone or in combination of two or more.

(6) Antireflection film An antireflection film may be formed on the hard coat layer, particularly on the hard coat layer on the surface (convex surface) where the photochromic film is not provided. The material and formation method of the antireflection film are not particularly limited, and a single layer or a multilayer film made of a known inorganic oxide can be used.
Examples of the inorganic oxide include silicon dioxide (SiO ₂ ), zirconium oxide (ZrO ₂ ), aluminum oxide (Al ₂ O ₃ ), niobium oxide (Nb ₂ O ₅ ), yttrium oxide (Y ₂ O ₃ ), and the like. Can be mentioned.
In addition, a single-layer or multilayer organic antireflection film composed of an organic silicon compound and inorganic fine particles and having a refractive index adjusted according to the type of inorganic fine particles can also be used.

2. Example <Example 1>
Examples of the plastic lens according to the present invention will be described below.
(1) Preparation of photochromic liquid First, 20 parts by mass of trimethylolpropane trimethacrylate, 35 parts by mass of BPE oligomer (2,2-bis (4-methacryloyloxypolyethoxyphenyl) propane), EB6A (polyester oligomer hexaacrylate) in a plastic container ) 100 parts by mass of a radically polymerizable monomer comprising 10 parts by mass, 10 parts by mass of polyethylene glycol diacrylate having an average molecular weight of 532, and 10 parts by mass of glycidyl methacrylate were prepared.

  Next, 3 parts by mass of chromene represented by the following chemical formula 1 as a photochromic dye and LS765 (bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl (1,2,2) as an antioxidant , 6,6-pentamethyl-4-piperidyl) sebacate), 0.4 part by weight of CGI-184 (1-hydroxycyclohexyl phenyl ketone) as an ultraviolet polymerization initiator, and CGI403 (bis (2,6- 0.1 parts by mass of dimethoxybenzoyl-2,4,4-trimethylpentylphosphine oxide) was added.

  And the photochromic liquid was obtained by defoaming the liquid to which these antioxidant and the ultraviolet-ray polymerization initiator were added for 2 minutes with the rotation revolution type stirring deaerator (AR-250 by Shinkey Co., Ltd.). The viscosity of the obtained liquid was 200 mpa / s.

(2) Formation of photochromic film About 2 g of the obtained photochromic liquid was weighed, washed cleanly and dropped onto the concave surface of the lens substrate on which a primer layer was previously formed on a plastic substrate (CR39: manufactured by PPC). The primer layer was formed by applying a polyurethane dispersion (polycarbonate polyol polyurethane emulsion, viscosity 100 CPS, solid content concentration 38% by mass) in which an acrylic group was introduced into a polyurethane skeleton as a primer solution. The lens substrate was rotated at 600 rpm for 20 seconds, and the concave surface of the lens substrate was coated by a spin coating method.
A plastic substrate having a lens center thickness of 2.0 mm and a lens power of 0.00D (diopter) was used as the plastic substrate.

Then, in a nitrogen atmosphere, ultraviolet rays were irradiated from the concave surface side of the lens substrate coated with the photochromic solution with a UV lamp (manufactured by Toshiba Lighting & Technology Corp.) to cure the photochromic solution. The ultraviolet irradiation was performed for 165 seconds at an irradiation distance of 330 mm.
In addition, it was 30 micrometers when the film thickness of the photochromic film | membrane formed by hardening was measured by the spectral interference film thickness measuring method.

Next, the lens substrate on which the photochromic film was formed was subjected to heat treatment (annealing) at a temperature of 110 degrees for 100 minutes, and then UV ozone treatment (manufactured by Eye Graphics Co., Ltd.) was performed for 180 seconds.
As described above, the plastic lens according to this example was manufactured.

<Example 2>
The lens of this example is a lens obtained by the same method and the same specifications as the plastic lens of Example 1 except that a lens substrate capable of absorbing ultraviolet rays having a wavelength of 350 nm or less is prepared.

<Example 3>
The lens of this example is a lens obtained by the same method and the same specifications as those of the plastic lens of Example 1 except that a lens substrate capable of absorbing ultraviolet light having a wavelength of 365 nm or less is prepared.

<Example 4>
The lens of this example is a lens obtained by the same method and the same specifications as the plastic lens of Example 1 except that a lens substrate capable of absorbing ultraviolet light having a wavelength of 392 nm or less is prepared.

<Example 5>
The lens of this example is a lens obtained by the same method and the same specifications as the plastic lens of Example 1 except that a lens substrate capable of absorbing ultraviolet light having a wavelength of 399 nm or less is prepared.

<Comparative Example 1>
The lens of this comparative example is a plastic lens formed so that the convex side specification of the lens of Example 1 is the concave side and the concave side specification of Example 1 is the convex side. The point is a plastic lens similar to the conventional one in which a photochromic film is formed on the convex surface side.

<Comparative example 2>
The lens of this comparative example is a plastic lens obtained by the same method and the same specifications as the lens of Example 1, except that a lens substrate capable of absorbing ultraviolet light having a wavelength of 413 nm or less is prepared.

<Comparative Example 3>
The lens of this comparative example is a plastic lens obtained by the same method and the same specifications as the lens of Example 1, except that a lens substrate capable of absorbing ultraviolet light having a wavelength of 487 nm or less is prepared.

In the lens substrates of Examples 1 to 5 and Comparative Examples 1 to 3 described above, the light transmission intensity integrated every 20 nm from the wavelength 300 nm to 420 nm, the percentage of the integrated transmitted light intensity at the wavelength 300 nm to 420 nm, and the following formula: Table 1 below shows the percentage of color development when the comparative example 1 shown is 100. FIG. 2 shows a graph with the light intensity ratio relative to Comparative Example 1 as the horizontal axis and the light intensity ratio relative to Comparative Example 1 as the vertical axis.
The accumulated transmission intensity is the intensity of light reaching the photochromic film. In Comparative Example 1, the photochromic film is formed on the convex surface side, so that the irradiated light reaches as it is. For this reason, it is 100%.

As is apparent from Table 1 and FIG. 2, the dimming ability of Example 5 when the ratio of the accumulated transmitted light amount from the wavelength of 300 nm to 420 nm is 14% or more of normal is verified, and the comparison in which the photochromic film is formed on the convex surface A capacity greater than 70% of Example 1 was observed. Further, it was confirmed that the dimming ability was about 90% when the ratio of the accumulated transmitted light amount was 27% or more.
Usually, a hard coat layer is provided on both the convex and concave surfaces, and an antireflection film is provided on the convex surface side. In the above experiment, these are comparisons when these are not provided, but since the ratio of the amount of light reaching the photochromic film is obtained, the dimming ability is similarly estimated even when an antireflection film or a hard coat layer is provided. be able to. That is, if the amount of light reaching the photochromic film after passing through the lens substrate including the additional film such as the hard coat layer is 14% or more compared to the amount of light when the photochromic film is provided on the convex surface side, the dimming ability It can be said that about 70% can be obtained.

Next, three plastic lenses of Example 1 and Comparative Example 1 were manufactured and subjected to an impact resistance test. In addition, three lenses (Comparative Example 4) provided with an impact resistant primer layer on the concave surface side of the lens of Comparative Example 1 were produced and tested at the same time.
In the impact resistance test, a drop ball test method defined in US FDA (Food and Drug Administration) standard was performed. In the test, a 16 g ball was used, and when the lens was cracked or cracked after the test, the test was rejected (x), and when the lens appearance did not change from that before the test, the test was passed (o).
The results are shown in Table 2.

  From the above drop ball test, it was confirmed that the lens according to this example had impact resistance equivalent to that of a conventional photochromic lens provided with an impact resistant primer.

As described above, since the photochromic film is formed on the concave surface side of the lens substrate in the plastic lens of the present invention, the photochromic film is less susceptible to external impact during mounting and storage. For this reason, it is possible to greatly suppress deterioration due to the damage of the photochromic film.
Even if a hard coat layer, antireflection film, etc. are laminated on the photochromic film, the concave surface of the lens substrate is not susceptible to external impacts, so cracks and scratches are not found on the hard coat layer or antireflection film. It can be suppressed from occurring.

  Furthermore, the impact from the lens convex surface side can be buffered by forming a soft photochromic film on the lens concave surface side. For this reason, resistance to impact from the convex surface side of the lens is also improved, and it is possible to prevent the lens itself from being cracked even when subjected to some impact during mounting. For this reason, by appropriately selecting the thickness and material of the photochromic film, it is possible to obtain the desired impact resistance without separately providing a primer layer for impact resistance.

In this example, the photochromic liquid is cured by irradiating ultraviolet rays from the concave side of the lens substrate. However, in the present invention, it is preferable to use a lens substrate that does not contain an ultraviolet absorber or is made of a material having a predetermined ultraviolet transparency.
In the case of using such a lens substrate, it is also possible to cure the photochromic film by irradiating with ultraviolet rays through the lens substrate from the convex surface side.

  In particular, a photochromic film can be formed in a shorter time if ultraviolet curing is simultaneously performed from both the concave and convex surfaces. Further, at the time of curing, the photochromic film emits heat by absorbing ultraviolet rays. However, since the curing process can be completed in a short time, deterioration of the photochromic compound due to excessive heat history can be suppressed.

  The embodiments and examples of the plastic lens according to the present invention have been described above. The present invention is not limited to the above-described embodiment, and it is needless to say that the present invention includes various conceivable forms without departing from the gist of the present invention described in the claims.

  DESCRIPTION OF SYMBOLS 1 ... Plastic substrate, 2, 5 ... Hard-coat layer, 3, 6 ... Antireflection film, 4 ... Photochromic film, 7 ... Lens substrate, 100 ... Lens

Claims (3)

A meniscus-shaped lens substrate having optical transparency in at least a part of the wavelength range of 200 nm to 420 nm, and having a concave surface and a convex surface;
A photochromic film formed on the concave side of the lens substrate;
With plastic lens.   2. The plastic lens according to claim 1, wherein the lens substrate has an integrated transmittance of 14% or more in a wavelength ray range of a wavelength of 300 nm or more and 420 nm or less.   The plastic lens according to claim 1 or 2, wherein the photochromic film contains a photochromic dye that exhibits a photoisomerization reaction in a visible light region having a wavelength of 420 nm or less.

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