TRANSPARENT PLASTIC SUBSTRATE AND PLASTIC LENS

Description

Field of Invention

[0001] The present invention relates to a transparent plastic substrate and a plastic lens that has a high cut rate of blue light.Background Art

[0002] In a transparent plastic substrate and a plastic lens, the glare can be reduced, and the visibility and the contrast can be enhanced, by cutting a light ray in the blue region (having a wavelength range of 380-500 nm). With respect to the health of eyes, a light ray in the blue region (380-500 nm) has large energy and thus is said to be a factor damaging retina. The damage due to blue light is referred to as "blue light hazard", and light in the low wavelength side around 380-420 nm is the most dangerous, and the light in the region is said to be desirably cut.

[0003] For solving the problem, for example, JP-A-2012-093689 proposes a lens having a multilayer film disposed on a convex surface of a plastic member, in which the multilayer film has an average reflectance of 2-10% in a wavelength range of 400-500 nm. However, the cut rate of blue light measured for the lens is approximately 30%.

[0004] JP-A-2008-056854 describes a polymerizable composition for a lens that contains a benzotriazole ultraviolet ray absorbent and is enhanced in light cut rate.

[0005] WO 2010095837 discloses a resin composition for a high refractive index optical lens having heat and impact resistance, the composition comprising a diisocyanate mixture consisting of 50-85 wt.% of dicyclohexyl methane diisocyanate and 15-50 wt.% of 1,6-hexamethylene diisocyanate; and 1,2-bis (2-mercaptoethylthio) -3-mercaptopropane trimethylolpropane tris(mercaptopropionate), and pentaerythritol tetrakis (mercaptopropionate).

[0006] US 6,770,692 relates to a plastic composition which has transmittances of ≤ 1% at 390 nm, of ≤ 10% at 400 nm, and of 40-60% at 410 nm, and comprises a plastic base material, 0.1-1.0 wt.% of a UV-absorbent of formula (1) and 0.1-1.0 ppm by weight of a violet colorant of formula (2): wherein, R 1< and R 2< each independently are C 1-8 -alkyl, R is optionally substituted phenyl group, and X is -OH or-NHR.Summary of InventionTechnical Problem

[0007] An object of the present invention is to provide a transparent plastic substrate having a high cut rate of blue light, and a plastic lens containing the same.Solution to Problem

[0008] As a result of earnest investigations made by the present inventors for achieving the object, it has been found that the object can be achieved by adding an ultraviolet ray absorbent (UV-absorber hereinafter) containing a benzotriazole compound having a particular structure containing a group imparting a mesomeric effect into a transparent plastic substrate, and thus the present invention has been completed.

[0009] The present invention thus provides a plastic lens which has a cut rate of light having a wavelength of 410 nm of ≥ 50% and comprises a transparent plastic substrate and at least one functional layer, wherein the transparent plastic substrate comprises (1) a resin component comprising a (thio)urethane resin obtained by reacting bis(isocyanatomethyl)bicyclo[2.2.1]heptane, pentaerythritol tetrakis (3-mercaptopropionate) and 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane; (2) 1.0-1.90 parts by mass, per 100 parts by mass of the resin component, of a benzotriazole compound of the formula (1-1): wherein R 1 is C 1-3 -alkyl or C 1-3 -alkoxy, m is 0 or 1, and R 2 is C 1-12 -alkyl or C 1-12 -alkoxy, and the at least one functional layer is selected from a cured film, a primer layer, an antireflection film and a water repellent film.

[0010] Preferred embodiments of the invention are as defined in the appended dependent claims and / or in the following detailed description.Advantageous Effects of Invention

[0011] According to the present invention, a transparent plastic substrate having a high cut rate of blue light, and a plastic lens containing the same, can be provided.Description of Embodiments

[0012] The present transparent plastic substrate contains the benzotriazole compound of formula (1-1) as UV-absorber: wherein R 1 is C 1-3 -alkyl or C 1-3 -alkoxy, m is 0 or 1, and R 2 is C 1-12 -alkyl or C 1-12 -alkoxy,

[0013] In the formula (1-1), Cl is a group imparting a mesomeric effect. It is expected that this group present on the benzotriazole ring enhances the cut rate of blue light.

[0014] The substitution position of Cl is preferably the 5-position of the triazole ring.

[0015] In formula (1-1), R 2 r is C 1-12 -alkyl or C 1-12 -alkoxy, and for each of them, the number of carbon atoms is preferably 1-8, more preferably 2-8, and further preferably 4-8.

[0016] The alkyl and the alkoxy each may be branched or linear. Among alkyl and alkoxy, alkyl is preferred.

[0017] Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, n-octyl, 1,1,3,3-tetramethylbutyl, nonyl, decyl, undecyl and dodecyl, and among these, at least one selected from n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl and 1,1,3,3-tetramethylbutyl is preferred, n-butyl, sec-butyl, tert-butyl and 1,1,3,3-tetramethylbutyl are more preferred, and tert-butyl is further preferred.

[0018] Examples of the alkoxy group include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy and dodecyloxy, and among these, butoxy and ethoxy are preferred.

[0019] In formula (1-1), the substitution position of R 2 is preferably the 3-, 4- or 5-position with respect to the substitution position of the benzotriazolyl group.

[0020] In formula (1-1), R 1 R 1 is C 1-3 -alkyl or C 1-3 -alkoxy, and specific examples thereof include the groups described for R 2 that conform in the number of carbon atoms. Among them, methyl and ethyl are preferred. If R 1 is one of these groups, an excellent cut rate of blue light is obtained. If the number of carbon atoms of R 1 is ≥ 4 (for example, 2-(3,5-di-t-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole), the compound is a persistent compound, which has a large environment load and may bring possible influence to human body, and thus may be designated as a manufacturing prohibited substance in some cases. However, the compound of formula (1-1) can be decomposed relatively easily, and also has an advantage of less influence on human body.

[0021] In formula (1-1), the substitution position of R 2 is preferably the 5-position with respect to the substitution position of the benzotriazolyl group.

[0022] Specific examples of the benzotriazole compound of formula (1-1) include 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole, 2-(3-tert-butyl-2-hydroxy-5-ethylphenyl)-5-chloro-2H-benzotriazole, 5-chloro-2-(3,5-dimethyl-2-hydroxyphenyl)-2H-benzotriazole, 5-chloro-2-(3,5-diethyl-2-hydroxyphenyl)-2H-benzotriazole, 5-chloro-2-(2-hydroxy-4-methoxyphenyl)-2H-benzotriazole, 5-chloro-2-(4-ethoxy-2-hydroxyphenyl)-2H-benzotriazole, 2-(4-butoxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole and 5-chloro-2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole.

[0023] Among these, 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole, 2-(3-tert-butyl-2-hydroxy-5-ethylphenyl)-5-chloro-2H-benzotriazole, 5-chloro-2-(4-ethoxy-2-hydroxyphenyl)-2H-benzotriazole and 2-(4-butoxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole are preferred.

[0024] The present transparent plastic substrate preferably contains the benzotriazole compound that is used in an amount of 1.0-1.9 parts by mass (pbm) per 100 pbm of the resin component (i.e., a monomer and / or a polymer) constituting the transparent plastic substrate. The amount of the benzotriazole compound added may vary depending on e.g. the kind of the resin component and the target UV-absorbing characteristics.

[0025] The resin component constituting the transparent plastic substrate is a resin component comprising a (thio)urethane resin obtained by reacting bis(isocyanatomethyl)bicyclo[2.2.1]heptane, pentaerythritol tetrakis (3-mercaptopropionate) and 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane. Other monomers for the transparent plastic substrate such as, a monomer for forming the (thio)urethane resin may be added for modifying the lens properties such as, the impact resistance and the processability.

[0026] In the present invention, a diethylene glycol bisallyl carbonate monomer as an optional component may be added to the monomer forming the (thio)urethane resin.

[0027] As the diethylene glycol bisallyl carbonate monomer, applicable are sole diethylene glycol bisallyl carbonate, and a monomer mixture containing diethylene glycol bisallyl carbonate and a monomer that is copolymerizable therewith. Specific examples of the copolymerizable monomer include an aromatic vinyl compound, such as, styrene, α-methylstyrene, vinyltoluene, chlorostyrene, chloromethylstyrene and divinylbenzene; a mono(meth)acrylate compound, such as, methyl (meth)acrylate, n-butyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, glycidyl (meth)acrylate and benzyl methacrylate; a mono(meth)acrylate compound having a hydroxyl group, such as, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 3-phenoxy-2-hydroxypropyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate; a di(meth)acrylate compound, such as, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2-hydroxy-1,3-di(meth)acryloxypropane, 2,2-bis(4-((meth)acryloxyethoxy)phenyl)propane, 2,2-bis(4-((meth)acryloxy-diethoxy)phenyl)propane and 2,2-bis(4-((meth)acryloxy-polyethoxy)phenyl)propane; a tri(meth)acrylate compound, such as, trimethylolpropane trimethacrylate and tetramethylolmethane trimethacrylate; a tetra(meth)acrylate compound, such as, tetramethylolmethane tetra(meth)acrylate (provided that the term (meth)acrylate in the description means methacrylate or acrylate); diallyl phthalate, diallyl isophthalate, diallyl terephthalate.

[0028] In the present transparent plastic substrate, the monomer having a thiourethane structure is used as a main component, and the transparent plastic substrate is preferably polymerized from a raw material having a total mass of the polyisocyanate compound and the polythiol compound as the raw material monomers of ≥ 0.6 with respect to the total mass of the raw material monomers being 1.

[0029] Examples of the production method of the present transparent plastic substrate include a method of mixing at least one kind of the benzotriazole compound selected from the formula (1-1) with, a monomer forming the (thio)urethane resin, and then polymerizing the monomers. The polymerization method of the raw material monomer is not particularly limited, and in general, cast polymerization is employed. Specifically, at least one kind of the benzotriazole compound of formula (1-1) may be mixed with the raw material monomer, and then the mixed liquid may be charged in a mold for forming a lens and heated to a temperature generally of 20-150°C, thereby providing the transparent plastic substrate.

[0030] As another production method of the present transparent plastic substrate, a method may also be employed wherein at least one kind of the benzotriazole compound of formula (1-1) and an appropriate surfactant are dissolved or dispersed in water, and a transparent plastic substrate is immersed therein to infiltrate the transparent plastic substrate with the benzotriazole compound, thereby providing the transparent plastic substrate.

[0031] The mixed liquid of the benzotriazole compound of formula (1-1) and the raw material monomer for the transparent plastic substrate may contain depending on necessity a polymerization catalyst described in e.g. JP-A-07-063902, JP-A-07-104101, JP-A-09-208621 and JP-A-09-255781, and an assistant, such as, an internal releasing agent, an antioxidant, a fluorescent whitening agent and a bluing agent, described in e.g. JP-A-01-163012 and JP-A-03-281312. The transparent plastic substrate obtained in the present invention may be subjected to a dyeing treatment using a colorant.

[0032] The transparent plastic lens of the present invention contains the benzotriazole compound of formula (1-1), and has, a functional layer, i.e. it contains the transparent plastic substrate and a functional layer.

[0033] The present transparent plastic lens preferably is a plastic lens for spectacles.

[0034] The functional layer is at least one selected from a cured film, a primer layer, an antireflection film and a water repellent film.

[0035] Specifically, for enhancing the scratch resistance, a cured film may be formed on the transparent plastic substrate by using a coating liquid containing fine particles of an inorganic material, such as, an organosilicon compound, tin oxide, silicon oxide, zirconium oxide and titanium oxide. For enhancing the impact resistance, a primer layer containing a polyurethane as a main component may be provided. For imparting an antireflection function, an antireflection film may be formed by using e.g. silicon oxide, titanium dioxide, zirconium oxide and tantalum oxide. For enhancing the water repelling property, a water repellent film may be formed on the antireflection film by using an organosilicon compound having a fluorine atom.

[0036] In the present transparent plastic lens, the benzotriazole compound of formula (1-1) is contained in the transparent plastic substrate, , and may be contained in the functional layer.

[0037] As a method for producing the plastic lens having the benzotriazole compound contained in the functional layer thereof, such a method may be employed that at least one kind of the benzotriazole compound of formula (1-1), the resin components, and depending on necessity a solvent are mixed to prepare a composition, and the composition is coated on at least one surface of a plastic lens substrate, and then cured to form the functional layer, thereby providing the transparent plastic member.

[0038] The present transparent plastic lens (or the transparent plastic substrate) preferably has a cut rate of light in the blue region of 380-500 nm of ≥ 35%, more preferably ≥ 40%, and while not limited, preferably ≤ 60%, more preferably ≤ 50%.

[0039] The cut rate of light having a wavelength of 410 nm is ≥ 50%, preferably ≥ 60%.

[0040] The term transparent in the present invention means that a material is transparent to such an extent that the side therebehind can be viewed.

[0041] The present transparent plastic substrate preferably has a light transmittance in a wavelength range of 400-700 nm of ≥ 70%, more preferably ≥ 80%, and further preferably ≥ 90%.Examples

[0042] The present invention will be described specifically with reference to examples. A plastic lens will be described as an example of the transparent plastic member. The plastic lenses thus obtained were measured for the properties in the following manners.(1) Measurement of Cut Rate of Light in Blue Region (Wavelength Range of from 380 to 500 nm)

[0043] The transmittances in a wavelength range of 380-500 nm were measured with a spectrophotometer (U-4100, produced by Hitachi, Ltd.), and the cut rate of blue light was calculated from the transmittances (T) of every 10 nm according to the following expression. Blue light cut rate % = 100 − ∑ 380 nm 500 nm T 13 (2) Measurement of Cut Rate at 410 nm

[0044] The light transmittance at a wavelength of 410 nm was measured with a spectrophotometer, and the cut rate of light was calculated according to the following expression. Cut rate of light % = 100 − transmittance at 410 nm Example 1

[0045] 50.28 pbm of bis(isocyanatomethyl)bicyclo[2.2.1]heptane as a raw material monomer for a lens, 0.06 pbm of dimethyltin dichloride as a catalyst, 0.15 pbm of an acidic phosphate ester, JP-506H (produced by Johoku Chemical Co., Ltd.), as a releasing agent, and 1.90 pbm of 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole as a UV-absorbent were mixed by stirring, to which 25.50 pbm of pentaerythritol tetrakis(3-mercaptopropionate) and 24.22 pbm of 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane as lens raw materials were then further added, and the components were mixed by stirring under a reduced pressure of 10 mmHg for 30 minutes, thereby preparing a monomer composition for a lens. The monomer composition for a lens was charged in a mold for molding a lens formed of a glass mold and a resin gasket (set to 0.00D and thickness of 1.6 mm) provided in advance, and polymerized in an electric furnace at a temperature over 20°C to 120°C for 24 hours. After completing the polymerization, the gasket and the mold were removed, and the resulting molded article was heat-treated at 120°C for 2 hours, thereby providing a transparent plastic lens.

[0046] The results obtained by measuring the resulting lens for the cut rate at 410 nm and the cut rate of blue light are shown in Table 1.Example 2 and Comparative Example 1

[0047] Transparent plastic lenses were obtained in the same manner as in Example 1 except that the kinds and the amounts of the UV-absorbent were changed as shown in Table 1.

[0048] The results obtained by measuring the resulting lenses for the cut rate at 410 nm and the cut rate of blue light are shown in Table 1. Table 1Lens raw material monomer / resin(proportion in 100 parts by mass)Ultraviolet ray absorbent(part by mass)Cut rate at 410 nmCut rate of blue lightExample 1M-150.28%M-225.50%U-11.9099%46%M-324.22%Example 2M-150.28%M-225.50%U-11.0099%45%M-324.22%Comparative Example 1M-150.28%M-225.50%U-51.0035%32%M-324.22%

[0049] Each monomer or resin, and each ultraviolet absorbent shown in the table are as follows.Monomer and Resin

[0050] M-1: bis(isocyanatomethyl)bicyclo[2.2.1]heptane M-2: pentaerythritol tetrakis(3-mercaptopropionate) M-3: 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane Ultraviolet Absorbents

[0051] U-1: 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole U-5: 2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole

[0052] While the plastic lenses are shown in the examples, the same effect can be obtained by providing a transparent plastic member containing the benzotriazole compound of formula (1-1), for example, on a display screen of a personal computer, a mobile phone and a smartphone.

Claims

1. A plastic lens which has a cut rate of light having a wavelength of 410 nm of ≥ 50% and comprises a transparent plastic substrate and at least one functional layer, wherein the transparent plastic substrate comprises (1) a resin component comprising a (thio) urethane resin obtained by reacting bis(isocyanatomethyl)bicyclo[2.2.1]heptane, pentaerythritol tetrakis (3-mercaptopropionate) and 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane; (2) 1.0-1.90 parts by mass, per 100 parts by mass of the resin component, of a benzotriazole compound of the formula (1-1) : wherein R1 is C1-3-alkyl or C1-3-alkoxy, m is 0 or 1, and R2 is C1-12-alkyl or C1-12-alkoxy, and the at least one functional layer is selected from a cured film, a primer layer, an antireflection film and a water repellent film.

2. The plastic lens of claim 1, wherein the benzotriazole compound is at least one of 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole, 2-(3-tert-butyl-2-hydroxy-5-ethylphenyl)-5-chloro-2H-benzotriazole, 2-(4-ethoxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole and 2-(4-butoxy-2-hydroxyphenyl)-5-chloro-2H-benzotriazole.

3. The plastic lens of claim 2, wherein the benzotriazole compound is at least one of 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole, and 2-(3-tert-butyl-2-hydroxy-5-ethylphenyl)-5-chloro-2H-benzotriazole.

4. The plastic lens of any of claims 1-3, which has a cut rate of light in the wavelength range of 380-500 nm of ≥ 35%.

5. The plastic lens of any of claims 1-4, wherein the at least one functional layer includes a cured film.

6. The plastic lens of claim 5, wherein the cured film is formed by a coating liquid comprising fine particles of an inorganic material selected from an organosilicon compound, tin oxide, silicon oxide, zirconium oxide and titanium oxide.

7. The plastic lens of any of claims 1-6 which is a spectacle lens.