Methacrylic resin composition, color blindness correction lens, and optical tool for color blindness correction

Abstract

Provided are an optical tool for color blindness correction, a color blindness correction lens, and a methacrylic resin composition suitably used in the color blindness correction optical tool or color blindness correction lens provided with color correction functionality for persons suffering from type I colorblindness.　The present invention is an optical tool for color blindness correction, a color blindness correction lens, and a methacrylic resin composition including a methacrylic resin, a dye A that has a peak absorption wavelength at 530-570 nm, a dye B that has a peak absorption wavelength at 470-510 nm, and an ultraviolet light absorbing agent U that has a peak absorption wavelength at 330-380 nm, and satisfying expressions (1) to (3) below.　(3): 3 < (a×α) + (b×β) < 20 (1) 1.0 < (b×β) / (a×α) < 7.0 (2) 0.1 ≤ u ≤ 1.0 (In the expression, a and b indicate the concentrations (mass, ppm) of the dyes A and B, and u indicates the content (mass%) of the ultraviolet light absorbing agent U.　α and β indicate the absorbance indicated by the peak absorption wavelengths of methyl methacrylate solutions having 1 ppm of the dyes A and B at an optical path length of 20 mm.)

Description

Methacrylic resin composition, color vision correction lens, and color vision correction optical device

[0001] The present invention relates to a methacrylic resin composition, a color vision correcting lens, and a color vision correcting optical instrument.

[0002] The retina of the human eye contains three types of cone cells: L cones that sense red light, M cones that sense green light, and S cones that sense blue light, each of which has visual pigments that respond to different wavelength characteristics. The function of these cones allows humans to perceive colors normally. In contrast, color vision deficiency generally refers to a condition in which it is difficult to perceive differences between some of the colors that most people can distinguish, and is thought to be caused by a malfunction of at least one of the three types of cone cells.

[0003] Color vision correction filters are known as optical devices that aid the color discrimination ability of people with such congenital color vision deficiencies (also referred to as (congenital) color vision deficiencies). For example, Patent Document 1 describes an optical filter that specifies a transmission spectrum shape with a trough at 400 to 450 nm, a peak at 450 to 525 nm, a trough at 525 to 595 nm, and a peak at 595 nm or above, in which the minimum or maximum transmittance values ​​in the above wavelength ranges satisfy a specific relationship. Patent Document 1 also describes that the optical filter can be used as a color vision correction filter that improves the visibility of green traffic lights for color vision deficiencies with a strong green sensitivity, while maintaining a color vision correction function that suppresses the transmittance of green light.

[0004] However, in addition to color vision deficiencies characterized by a strong sensitivity to green, there are other color vision deficiencies, such as type 1 color blindness, which causes the inability to perceive red normally. For example, people with type 1 color blindness cannot perceive red normally due to dysfunction of L-cone cells, which can cause inconvenience in daily life. According to the FY2013 Research Report on Facilitating Transportation for Persons with Color Vision Impairment by the Ministry of Land, Infrastructure, Transport and Tourism's Policy Bureau, situations in which the red color used is inconspicuous or difficult for people with type 1 color blindness to see include, for example, traffic congestion information displayed on LEDs on highways during the day, next station displays inside trains, the color of emergency buttons themselves, the current location on maps providing local guidance, fares (letters) displayed inside ticket vending machine buttons, and letters (LED displays) on fare tables inside buses. However, due to its characteristics, the optical filter described in Patent Document 1 is not sufficient to provide color vision deficiency relief to people with type 1 color blindness.

[0005] Japanese Patent Application Laid-Open No. 2021-71548

[0006] An object of the present invention is to provide a methacrylic resin composition suitable for use in color vision correcting lenses or optical devices for color vision correction that have a color vision correcting function for persons with type 1 color vision deficiency. Another object of the present invention is to provide color vision correcting lenses and optical devices for color vision correction that use this methacrylic resin composition.

[0007] That is, the problems of the present invention have been solved by the following means: [1] A methacrylic resin composition comprising a methacrylic resin, a dye A having an absorption maximum wavelength within a wavelength range of 530 to 570 nm, a dye B having an absorption maximum wavelength within a wavelength range of 470 to 510 nm, and an ultraviolet absorber U having an absorption maximum wavelength within a wavelength range of 330 to 380 nm, and satisfying the following formulas (1) to (3): 3<(a×α)+(b×β)<20 (1) 1.0<(b×β) / (a×α)<7.0 (2) (wherein a represents the concentration of dye A in the methacrylic resin composition, α represents the absorbance at the maximum absorption wavelength of dye A, b represents the concentration of dye B in the methacrylic resin composition, and β represents the absorbance at the maximum absorption wavelength of dye B. The units of a and b are ppm by mass. α and β are values ​​measured on a methyl methacrylate solution with a concentration of 1 ppm by mass at an optical path length of 20 mm.) 0.1≦u≦1.0 (3) (wherein u represents the content of ultraviolet absorber U in the methacrylic resin composition. The unit of u is % by mass.) [2] The methacrylic resin composition according to [1], which contains dye C having an absorption maximum wavelength in a wavelength range of 420 to 460 nm and satisfies the following formula (4): 1≦c≦12 (4) (wherein c represents the concentration of dye C in the methacrylic resin composition. The unit of c is ppm by mass.) [3] The methacrylic resin composition according to [1] or [2], in which a is 10 to 100 ppm by mass and α is 0.04 to 0.14. [4] The methacrylic resin composition according to any one of [1] to [3], in which b is 80 to 330 ppm by mass and β is 0.01 to 0.11. [5] The methacrylic resin composition according to any one of [1] to [4], in which dye A includes at least one of anthraquinone dyes, azo dyes, and pyrimidine dyes. [6] The methacrylic resin composition according to any one of [1] to [5], wherein the dye B includes at least one of a perinone dye and an azo dye.[7] The methacrylic resin composition according to any one of [1] to [6], wherein the ultraviolet absorber U comprises at least one of a benzotriazole ultraviolet absorber and a triazine ultraviolet absorber. [8] A color vision correcting lens obtained by molding the methacrylic resin composition according to any one of [1] to [7] into a lens shape. [9] An optical device for color vision correcting, comprising the methacrylic resin composition according to any one of [1] to [7].

[0008] The methacrylic resin composition of the present invention has a higher transmittance in the red region than in regions other than the red region, and also maintains a constant level of transmittance in regions other than the red region, thereby exhibiting a function of correcting or assisting for type 1 color vision deficiency. Therefore, the methacrylic resin composition of the present invention can be suitably used as a material for color vision correcting lenses or optical devices for color vision correction that are applicable to people with type 1 color vision deficiency. Furthermore, the color vision correcting lenses and optical devices for color vision correction of the present invention have excellent color vision correction functions for people with type 1 color vision deficiency.

[0009] Figure 1 shows the transmission spectra of the plates of Examples 1 to 3 molded from the methacrylic resin composition of the present invention. Figure 2 shows the transmission spectra of the plates of Examples 4 to 6 molded from the methacrylic resin composition of the present invention. Figure 3 shows the transmission spectra of the plates of Examples 7 to 9 molded from the methacrylic resin composition of the present invention. Figure 4 shows the transmission spectra of the plates of Comparative Examples 1 to 3 molded from comparative methacrylic resin compositions.

[0010] In the present invention and this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In the transmission spectrum of the methacrylic resin composition of the present invention, the red region means a wavelength range of approximately 640 to 770 nm, the region other than the red region means a wavelength range of approximately 380 to 640 nm, and the blue to green region means a wavelength range of approximately 440 to 570 nm.

[0011] [Methacrylic Resin Composition] The methacrylic resin composition of the present invention comprises a methacrylic resin, a dye A (hereinafter also referred to simply as "dye A") having an absorption maximum wavelength in the wavelength range of 530 to 570 nm, a dye B (hereinafter also referred to simply as "dye B") having an absorption maximum wavelength in the wavelength range of 470 to 510 nm, and an ultraviolet absorber U (hereinafter also referred to simply as "ultraviolet absorber U") having an absorption maximum wavelength in the wavelength range of 330 to 380 nm, and the dyes A and B and ultraviolet absorber U contained in this methacrylic resin composition respectively satisfy the following formulas (1) to (3). In the methacrylic resin composition of the present invention, the dyes A and B and ultraviolet absorber U are dispersed (preferably dissolved) in the methacrylic resin, thereby making a molded article such as a color vision correcting lens using the methacrylic resin composition of the present invention into a molded article exhibiting a specific transmission spectrum derived from the dyes A and B and ultraviolet absorber U. This dispersion may be in a state where the component concentrations are constant (each component is uniformly dispersed), or in a state where the component concentrations vary randomly, regularly, etc., within a range that does not impair the intended function.

[0012] The methacrylic resin composition of the present invention has a higher transmittance in the red region than in regions other than the red region, and also maintains a constant level of transmittance in regions other than the red region, making it possible to obtain a color vision correcting lens that has a color vision correction function for people with type 1 color vision deficiency who can see colors other than red, such as blue and green, normally but have difficulty seeing red. Note that "maintaining a constant level of transmittance in regions other than the red region" means that a level of transmittance is maintained that does not pose a problem for visibility (does not significantly reduce normal visibility) even in regions other than the red region, and that a uniform color balance is ensured in the blue to green region. The reasons for this are thought to be as follows. That is, the methacrylic resin composition of the present invention suppresses the transmittance in the blue to green region by containing dye A and dye B. By satisfying 3<[(a×α)+(b×β)] in formula (1) described below, the transmittance in the red region is high enough to obtain the desired color vision correction function compared to the transmittance in regions other than the red region centered on the blue to green region, and by satisfying [(a×α)+(b×β)]<20, it is possible to maintain a level of transmittance that does not cause visibility problems in regions other than the red region centered on the blue to green region. Furthermore, by setting the ratio of the absorption of dye B to the absorption of dye A [(b×β) / (a×α)] defined in formula (2) described below within a specific range, and by setting the content u of ultraviolet absorber U within a specific range so that the absorption of ultraviolet absorber U in the blue region falls within a specific range according to formula (3) described below, it is possible to ensure a uniform color balance to the extent that colors in the blue to green region can be viewed normally by people with type 1 color vision deficiency.

[0013] In the present invention, when multiple absorption maxima exist within the wavelength range having a specific absorption maximum wavelength specified for each of dyes A to C, the wavelength showing the absorption maximum with the greatest absorbance is taken as the absorption maximum wavelength. Similarly, when multiple absorption maxima exist within the wavelength range having a specific absorption maximum wavelength specified for ultraviolet absorber U, the wavelength showing the absorption maximum with the greatest absorbance is taken as the absorption maximum wavelength. Furthermore, in the present invention, the absorption maximum wavelengths shown by each of dyes A to C and ultraviolet absorber U are values ​​measured in the state of a methyl methacrylate solution. Specifically, they can be measured by the method described in the Examples below. Furthermore, in the present invention, the absorbance α shown at the absorption maximum wavelength of dye A and the absorbance β shown at the absorption maximum wavelength of dye B are values ​​measured in a methyl methacrylate solution with a concentration of 1 ppm by mass, using an optical path length of 20 mm, using the method described in the Examples below.

[0014] In the methacrylic resin composition of the present invention, dye A and dye B are contained so as to satisfy the relationships of the following formulas (1) and (2). 3<(a×α)+(b×β)<20 (1) 1.0<(b×β) / (a×α)<7.0 (2) (In the formulas, a represents the concentration of dye A in the methacrylic resin composition, and means the proportion of dye A in the total amount (100% by mass) of all components constituting the methacrylic resin composition of the present invention. α represents the absorbance shown by the absorption maximum wavelength of dye A. However, when two or more types of dye A are contained, "a×α" in the above formula (1) means the sum of a×α for each dye. b represents the concentration of dye B in the methacrylic resin composition, and means the proportion of dye B in the total amount (100% by mass) of all components constituting the methacrylic resin composition of the present invention. β represents the absorbance shown by the absorption maximum wavelength of dye B. However, when two or more types of dye B are contained, "b×β" in the above formula (2) means the sum of b×β for each dye. The units of a and b are ppm by mass. α and β are values ​​measured for a methyl methacrylate solution with a concentration of 1 ppm by mass at an optical path length of 20 mm.

[0015] The lower limit of the value of [(a×α) + (b×β)] defined by the above formula (1) is preferably 5 or more, and more preferably 7 or more. The upper limit of the value of [(a×α) + (b×β)] defined by the above formula (1) is preferably 18 or less, more preferably 17 or less, and even more preferably 16 or less. The lower limit of the value of [(b×β) / (a×α)] defined by the above formula (2) is preferably 1.1 or more, and more preferably 1.2 or more. The upper limit of the value of [(b×β) / (a×α)] defined by the above formula (2) is preferably 6.5 or less, and more preferably 6.0 or less.

[0016] In the methacrylic resin composition of the present invention, the ultraviolet absorber U is contained so as to satisfy the following formula (3): 0.1≦u≦1.0 (3) (wherein u represents the content of the ultraviolet absorber U in the methacrylic resin composition, and means the proportion of the ultraviolet absorber U (when two or more types are contained, the total proportion) in the total amount (100 mass%) of all components constituting the methacrylic resin composition of the present invention. The unit of u is mass %). The content u of the ultraviolet absorber U defined by the above formula (3) is preferably 0.2 to 0.8 mass %, more preferably 0.3 to 0.7 mass %.

[0017] <Methacrylic Resin> The methacrylic resin constituting the methacrylic resin composition of the present invention is a resin having 50 parts by mass or more of monomer units derived from methacrylic acid or a methacrylic acid ester. Methacrylic resins have excellent transparency and weather resistance and are therefore used in eyeglasses, contact lenses, automobile parts, signboards, thin displays, etc. The methacrylic resin is preferably a resin containing monomer units derived from methyl methacrylate and monomer units derived from an acrylic acid ester, and the resin is obtained by polymerizing monomer components containing methyl methacrylate and an acrylic acid ester. The contents of the monomer units derived from methyl methacrylate and the monomer units derived from acrylic esters in the methacrylic resin can be selected as appropriate, but it is preferable that the content of the monomer units derived from methyl methacrylate is 85 to 100 parts by mass and the content of the monomer units derived from acrylic esters is 0 to 15 parts by mass, and it is more preferable that the content of the monomer units derived from methyl methacrylate is 90 to 100 parts by mass and the content of the monomer units derived from acrylic esters is 0 to 10 parts by mass. However, the total amount of the monomer units derived from methyl methacrylate and the monomer units derived from acrylic esters is 100 parts by mass. By setting the contents of the monomer units derived from methyl methacrylate and the monomer units derived from acrylic esters within the above ranges, the heat resistance of the methacrylic resin can be improved.

[0018] Examples of acrylic acid esters include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate. Among these, methyl acrylate and ethyl acrylate are preferred. The acrylic acid esters may be used alone or in combination of two or more.

[0019] As the polymerization method for polymerizing the monomer components, known polymerization methods such as suspension polymerization, solution polymerization, and bulk polymerization can be used, among which bulk polymerization is preferred. Either a batch method or a continuous method can be used for bulk polymerization, but a polymer can be obtained with high productivity by, for example, continuously feeding the monomer components, a polymerization initiator, and the like into a reaction vessel, allowing the mixture to remain in the reaction vessel for a predetermined time, and continuously withdrawing the resulting partial polymer.

[0020] The polymerization initiator used when polymerizing the monomer components may be a known radical polymerization initiator, such as an azo compound such as azobisisobutyronitrile, or a peroxide such as 1,1-di(tert-butylperoxy)cyclohexane. The polymerization initiator may be one type or two or more types.

[0021] When polymerizing the monomer components, a chain transfer agent can be used as needed. Preferred examples of the chain transfer agent include mercaptans such as n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, and 2-ethylhexyl thioglycolate. The chain transfer agent may be used alone or in combination of two or more types.

[0022] The molecular weight distribution index, defined as the weight average molecular weight / number average molecular weight, of the methacrylic resin used in the present invention is preferably 1.8 to 6.0. In particular, to obtain a methacrylic resin with a molecular weight distribution index of 2.2 or more, known polymerization methods such as a method using multiple radical polymerization initiators, a method using multiple chain transfer agents, or a method combining multiple polymerization steps are preferably used. The molecular weight distribution index can be measured by gel permeation chromatography (GPC).

[0023] The methacrylic resin having a molecular weight distribution index of 2.2 or more may be prepared by mixing two or more methacrylic resins having different weight-average molecular weights. Methods for mixing two or more methacrylic resins include, for example, melt-kneading, solvent-kneading, and dry-blending. From the viewpoint of productivity, melt-kneading and dry-blending are preferred. Examples of equipment used for mixing include ordinary mixers and kneaders, and specific examples include single-screw kneading extruders, twin-screw kneading extruders, ribbon blenders, Henschel mixers, Banbury mixers, and drum tumblers.

[0024] The methacrylic resin used in the present invention may be synthesized as described above, or may be purchased as a commercially available product, such as the Sumipex (trade name) series manufactured by Sumitomo Chemical Co., Ltd.

[0025] The content of the methacrylic resin in the methacrylic resin composition of the present invention (the total content when two or more types are contained) is usually more than 99.0 mass%, preferably more than 99.2 mass%, and more preferably more than 99.3 mass%, based on the total amount (100 mass%) of all components constituting the methacrylic resin composition. There is no particular upper limit, but it is usually less than 99.9 mass%, preferably less than 99.8 mass%, and more preferably less than 99.7 mass%.

[0026] <Dye A> The methacrylic resin composition of the present invention contains dye A. Dye A is a red to purple dye having an absorption maximum wavelength within a wavelength range of 530 to 570 nm. The wavelength range in which dye A has an absorption maximum wavelength is preferably 530 to 560 nm, and more preferably 530 to 550 nm.

[0027] Examples of dye A include anthraquinone dyes, azo dyes, and pyrimidine dyes, and preferably at least one of anthraquinone dyes, azo dyes, and pyrimidine dyes. Specific examples of dye A include anthraquinone dyes such as Solvent Red 52, Solvent Red 145, Solvent Red 150, Solvent Red 151, Disperse Violet 26, and Disperse Violet 28, azo dyes such as Solvent Red 195, and pyrimidine dyes such as Solvent Red 149.

[0028] As the dye A, one kind may be used alone, or two or more kinds may be used.

[0029] The concentration a of dye A is preferably 10 to 100 ppm by mass. Furthermore, the absorbance α of dye A at its maximum absorption wavelength is preferably 0.04 to 0.14, more preferably 0.05 to 0.13, and even more preferably 0.06 to 0.12. When dye A satisfies the preferred range of concentration a and / or the preferred range of absorbance α of its maximum absorption wavelength, the methacrylic resin composition of the present invention can be easily prepared so as to satisfy the above-mentioned formulas (1) and (2).

[0030] <Dye B> The methacrylic resin composition of the present invention contains dye B. Dye B is an orange to red dye having an absorption maximum wavelength within a wavelength range of 470 to 510 nm. The wavelength range in which dye B has an absorption maximum wavelength is preferably 480 to 510 nm, and more preferably 490 to 510 nm.

[0031] Examples of dye B include perinone dyes and azo dyes, and it is preferable to include at least one of perinone dyes and azo dyes. Specific examples of dye B include perinone dyes such as Solvent Red 135, Solvent Red 179, and Solvent Orange 60, and azo dyes such as Solvent Red 143.

[0032] As the dye B, one kind may be used alone, or two or more kinds may be used.

[0033] The concentration b of dye B is preferably 80 to 330 ppm by mass. The absorbance β of the absorption maximum wavelength of dye B is preferably 0.01 to 0.11, more preferably 0.02 to 0.10, and even more preferably 0.03 to 0.09. When dye B satisfies the preferred range of concentration b and / or the preferred range of absorbance β of the absorption maximum wavelength, the methacrylic resin composition of the present invention can be easily adjusted to satisfy the above-mentioned formulas (1) and (2).

[0034] <Ultraviolet Absorber U> The methacrylic resin composition of the present invention contains an ultraviolet absorber U. The ultraviolet absorber U is a material having a maximum absorption wavelength within a wavelength range of 330 to 380 nm. By including the ultraviolet absorber U in the methacrylic resin composition of the present invention, deterioration of the methacrylic resin due to ultraviolet rays is suppressed. In addition, by incorporating a certain amount of the ultraviolet absorber so as to satisfy the above-mentioned formula (3), an increase in the transmittance in the blue region is suppressed, and a uniform color balance in the blue to green region can be ensured. The wavelength range in which the ultraviolet absorber U has a maximum absorption wavelength is preferably 330 to 370 nm, and more preferably 340 to 360 nm.

[0035] Examples of the ultraviolet absorber U include benzotriazole-based ultraviolet absorbers and triazine-based ultraviolet absorbers, and it is preferable to include at least one of benzotriazole-based ultraviolet absorbers and triazine-based ultraviolet absorbers.

[0036] Examples of benzotriazole-based ultraviolet absorbers include 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole (e.g., Sumisorb 300 (manufactured by Sumika Chemtex Co., Ltd.), Tinuvin 326 (manufactured by BASF Corporation)), 2-(2-hydroxy-5-methylphenyl)benzotriazole (e.g., Sumisorb 200 (manufactured by Sumika Chemtex Co., Ltd.), Tinuvin P (manufactured by BASF Corporation)), 2-[2-hydroxy-3-(4,5,6,7-tetrahydro-1,3-dioxo-1H-isoindol-2-ylmethyl)-5-methylphenyl]-2H-benzotriazole (e.g., Sumisorb 250 (manufactured by Sumika Chemtex Co., Ltd.), SEESORB 706 (manufactured by Shipro Chemical Co., Ltd.)), 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole (e.g., Sumisorb 340 (manufactured by Sumika Chemtex Co., Ltd.), Tinuvin 329 (manufactured by BASF), SEESORB 709 (manufactured by Shipro Chemical Co., Ltd.)), 2,2'-methylenebis[6-(benzotriazol-2-yl)-4-tert-octylphenol] (e.g., Adekastab LA-31 (manufactured by ADEKA Corporation), Tinuvin 360 (manufactured by BASF Corporation)), 2-(2-hydroxy-5-methylphenyl)benzotriazole (e.g., LA-32 (manufactured by ADEKA Corporation)).

[0037] An example of a triazine-based ultraviolet absorber is 2,4,6-tris[4-(hexyloxy)-2-hydroxy-3-methylphenyl]-1,3,5-triazine (for example, LA-F70 (manufactured by ADEKA Corporation)).

[0038] Only one type or two or more types may be used as the ultraviolet absorber U. The content u of the ultraviolet absorber U is as described above.

[0039] The methacrylic resin composition of the present invention may contain dyes other than dye A, dye B, and ultraviolet absorber U (hereinafter referred to as "other dyes") within the scope of the effects of the present invention. That is, the methacrylic resin composition of the present invention may contain dyes A, B, and ultraviolet absorber U so as to satisfy the above-mentioned formulas (1) to (3), and may contain other dyes within a range in which the transmittance in the red region is higher than the transmittance in regions other than the red region and the transmittance in regions other than the red region is maintained at a constant level. Note that "the transmittance in the red region is higher than the transmittance in regions other than the red region" means that all transmittances in the red region consisting of the wavelength range of 640 to 770 nm are higher than any transmittance in regions other than the red region consisting of the wavelength range of 380 to 640 nm. When formed into a molded article, the transmittance in all of the above red regions is usually 70% or more, preferably 80% or more, and more preferably 90% or more. There is no particular upper limit, but 95% or less is practical. Furthermore, when a molded article is produced, the transmittance across the entire blue to green region, consisting of the wavelength range of 440 to 570 nm, should be approximately 5 to 65%, preferably 5 to 60%. Furthermore, to ensure a uniform color balance sufficient for people with type 1 color vision deficiency to be able to normally see colors in the blue to green region, the ratio of the maximum to the minimum transmittance in the blue to green region (minimum / maximum) is preferably 0.10 or greater, more preferably 0.15 or greater, and even more preferably 0.20 or greater. The upper limit of the ratio of the maximum to the minimum transmittance in the blue to green region (minimum / maximum) is preferably as close to 1.0 as possible. The methacrylic resin composition of the present invention may contain, as the other dye, a dye that absorbs in the red region as long as the effects of the present invention are not impaired, but it is preferable that it does not contain such a dye. Examples of other dyes that may be contained in the methacrylic resin composition of the present invention include, for example, dye C below.

[0040] <Dye C> The methacrylic resin composition of the present invention also preferably contains dye C (also simply referred to as "dye C") having an absorption maximum wavelength within a wavelength range of 420 to 460 nm. The wavelength range in which dye C has an absorption maximum wavelength is preferably 430 to 450 nm. By containing dye C in the methacrylic resin composition of the present invention, the waveform of the transmission spectrum exhibited by the methacrylic resin composition of the present invention can be adjusted, and the waveform of the transmission spectrum in the blue to green region consisting of approximately 440 to 570 nm can be adjusted to be flat, making it easier to adjust the ratio of the maximum value to the minimum value of the transmittance in the above-mentioned blue to green region (minimum value / maximum value) to be within a preferred range.

[0041] Examples of dye C include quinophthalone dyes, and preferably include quinophthalone dyes. Specific examples of dye C include quinophthalone dyes such as Disperse Yellow 54, Solvent Yellow 33, and Solvent Yellow 157.

[0042] As the dye C, one kind may be used alone, or two or more kinds may be used.

[0043] When the methacrylic resin composition of the present invention contains dye C, it is preferable that dye C be contained in the methacrylic resin composition of the present invention so as to satisfy the following formula (4): 1≦c≦12 (4) (wherein c represents the concentration of dye C in the methacrylic resin composition, and means the proportion of dye C (if two or more types are contained, this is the total proportion) in the total amount (100 mass%) of all components constituting the methacrylic resin composition of the present invention. The unit of c is ppm by mass.) The concentration c of dye C defined by the above formula (4) is preferably 1.5 to 12 mass ppm, more preferably 2 to 10 mass ppm. By setting the concentration c of dye C within the above preferred range, the waveform of the transmission spectrum in the blue to green region can be adjusted to be flatter.

[0044] <Other Components> The methacrylic resin composition of the present invention may contain additives such as a mold release agent, a polymerization inhibitor, a flame retardant, and a reinforcing material.

[0045] (Antioxidant) The methacrylic resin composition of the present invention may contain an antioxidant. When the methacrylic resin composition of the present invention contains an antioxidant, oxidation of the methacrylic resin is inhibited, and excellent weather resistance can be obtained. In this specification, the term "antioxidant" refers to a component that has the function of inhibiting oxidation of the methacrylic resin.

[0046] Examples of the antioxidant include hindered amine antioxidants, phenolic antioxidants, and phosphoric acid antioxidants. Preferably, the antioxidant is a hindered amine antioxidant, a phosphoric acid antioxidant, or a combination of both.

[0047] The antioxidants may be used alone or in combination of two or more.

[0048] When the methacrylic resin composition of the present invention contains an antioxidant, the content of the antioxidant (when two or more antioxidants are contained, the total proportion of the antioxidants) relative to the total amount (100% by mass) of all components constituting the methacrylic resin composition of the present invention is preferably 0.03 to 1% by mass, more preferably 0.05 to 0.3% by mass, and even more preferably 0.05 to 0.2% by mass. By ensuring that the content of the antioxidant is at or above the above-mentioned lower limit, oxidation of the methacrylic resin can be further suppressed, resulting in a methacrylic resin composition with excellent weather resistance. Furthermore, by ensuring that the content of the antioxidant is at or below the above-mentioned upper limit, a methacrylic resin composition with excellent color can be obtained. In addition, mold contamination during molding of the methacrylic resin composition can be prevented.

[0049] <Molded Articles and Applications> The form of the methacrylic resin composition of the present invention is not particularly limited, and may be a molded article molded according to a desired application. The methacrylic resin composition of the present invention also includes a mixture containing the components constituting the methacrylic resin composition of the present invention (dyes A and B, ultraviolet absorber U, and methacrylic resin) in a predetermined content ratio. Molded articles from the methacrylic resin composition of the present invention can be used for color vision correction, such as sheet-like color vision correction sheets, lens-like color vision correction lenses, and goggles molded into a desired shape. The shape, thickness, size, and other properties of these molded articles can be adjusted as needed to achieve the transmittance required for the molded article (product). That is, the methacrylic resin composition of the present invention can be used in color vision correction optical devices such as color vision correction signs, eyeglasses (monocle, pince-nez, and eyeglasses with handles), eyeglass attachment lenses, contact lenses, intraocular lenses, and goggles. Molded articles from the methacrylic resin composition of the present invention can be obtained by various molding methods, preferably injection molding. Specifically, a molded article of the methacrylic resin composition of the present invention can be obtained by using a mixture of the components constituting the methacrylic resin composition of the present invention (dyes A and B, ultraviolet absorber U, and a methacrylic resin) as a molding material, injecting the mixture into a mold cavity in a molten state, cooling it, and then removing the molded article from the mold. Specifically, for example, the methacrylic resin composition of the present invention is pelletized and charged into a cylinder from a hopper, the methacrylic resin composition is melted while rotating the screw, the screw is retracted to fill a predetermined amount of the methacrylic resin composition into the cylinder, and the molten methacrylic resin composition is injected into a mold while applying pressure by advancing the screw. The pressure is maintained for a certain period until the mold is sufficiently cooled, and then the mold is opened and the molded article is removed, thereby producing a molded article of the methacrylic resin composition of the present invention. The conditions for producing a molded article of the methacrylic resin composition of the present invention (e.g., the temperature inside the cavity, the melting temperature of the molding material, the mold temperature when the molding material is injected into the mold, the pressure when the resin composition is filled into the mold and then held) may be set appropriately and are not particularly limited.

[0050] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0051] The absorption spectra of the dyes and UV absorbers used in the Examples and Comparative Examples were measured as follows, and the maximum absorption wavelength and extinction coefficient were determined. The results are summarized in Table 1. (Measurement of Absorption Spectra) A methyl methacrylate solution containing 1 ppm by mass of the dye or UV absorber was used as a measurement sample, and the absorbance at an optical path length of 20 mm was measured in 1 nm increments in the wavelength range of 330 to 800 nm using a "U-4000 Spectrophotometer (product name)" manufactured by Hitachi High-Tech Science Corporation. From the obtained absorption spectrum, the "maximum absorption wavelength" was determined as described above, and the absorbance at this maximum absorption wavelength was taken as the "extinction coefficient."

[0052]

[0053] (Examples 1 to 9) A methacrylic resin ("Sumipex MH (trade name)" manufactured by Sumitomo Chemical Co., Ltd.), a dye, and an ultraviolet absorber were mixed in the proportions shown in Table 2. The resulting mixture was melt-kneaded using a single-screw extruder (screw diameter 40 mm) so that the resin temperature reached 250°C, extruded into a strand, cooled with water, and cut with a strand cutter to obtain pellets. From the resulting pellets, a 100 mm square flat plate having a thickness of 2 mm was produced using a heat compression molding machine at a molding temperature of 210°C. In Table 2, the units of the blending amounts of dyes A-1, B-1, and C-1, methacrylic resin, and ultraviolet absorber U-1 are shown in parentheses.

[0054]

[0055] For each of the prepared plates, a×α, b×β, (a×α)+(b×β), and (b×β) / (a×α) were calculated based on Tables 1 and 2. In these calculations, α was the absorption coefficient (absorbance at the maximum absorption wavelength) of dye A-1 listed in Table 1, β was the absorption coefficient (absorbance at the maximum absorption wavelength) of dye B-1 listed in Table 1, a was the concentration (unit: ppm by mass) of dye A-1 listed in Table 2, and b was the concentration (unit: ppm by mass) of dye B-1 listed in Table 2. The results are summarized in Table 3.

[0056]

[0057] Comparative Examples 1 to 3 Flat plates measuring 100 mm square and 2 mm thick were prepared in the same manner as in the Examples, except that a methacrylic resin (Sumipex MH (trade name) manufactured by Sumitomo Chemical Co., Ltd.) and a dye were mixed in the proportions shown in Table 4. In Table 4, the units of the blending amounts of dyes A-2 and C-2 and the methacrylic resin are shown in parentheses.

[0058]

[0059] For each of the prepared plates, a×α, b×β, (a×α)+(b×β), and (b×β) / (a×α) were calculated based on Tables 1 and 4. In the calculations, α was the absorption coefficient of dye A-2 (absorbance indicated by the maximum absorption wavelength) shown in Table 1, and a was the concentration of dye A-2 (unit: ppm by mass) shown in Table 4. Since no dye corresponding to dye B was included, β and b were set to zero. The results are summarized in Table 5.

[0060]

[0061] The spectral transmission spectra in the thickness direction (optical path length 2 mm) of the prepared flat plates were measured in 1 nm increments in the wavelength range of 360 to 800 nm using a Hitachi High-Tech Science U-4000 spectrophotometer (product name). Figure 1 shows the transmission spectra of the flat plates according to Examples 1 to 3. Figure 2 shows the transmission spectra of the flat plates according to Examples 4 to 6. Figure 3 shows the transmission spectra of the flat plates according to Examples 7 to 9. Figure 4 shows the transmission spectra of the flat plates according to Comparative Examples 1 to 3.

[0062] The results in Tables 3 and 5 and Figures 1 to 4 reveal the following: The plates of Examples 1 to 9, obtained by molding the methacrylic resin compositions of the present invention containing dyes A and B and ultraviolet absorber U and satisfying the above-mentioned formulas (1) to (3), all had transmittances in the red region of 90% or more, which were higher than the transmittances in the blue to green region. The transmittances in the blue to green region were also maintained at a level of 5 to 60%, sufficient for normal visibility. Furthermore, the ratios of the maximum to minimum transmittances in the blue to green region (minimum / maximum) were all 0.10 or more, ensuring a uniform color balance in the blue to green region. Therefore, the methacrylic resin compositions of the present invention are excellent materials for color vision correcting lenses or optical devices with color vision correction capabilities for individuals with type 1 color vision deficiency. On the other hand, the flat plates of Comparative Examples 1 to 3 obtained by molding comparative methacrylic resin compositions that did not contain dye B and ultraviolet absorber U and did not satisfy the above-mentioned formulas (2) and (3) all had a ratio of the maximum value to the minimum value of transmittance in the blue to green range (minimum value / maximum value) of 0.06 or less, and a uniform color balance in the blue to green range was not ensured.

[0063] The methacrylic resin composition of the present invention and a molded article thereof can be used in applications such as color vision correcting signs, eyeglasses (monocle, pince-nez, eyeglasses with handles), attachment lenses for eyeglasses, contact lenses, intraocular lenses, goggles, and other color vision correcting optical devices, and has high applicability in the optical field.

Claims

1. The ink comprises a methacrylic resin, a dye A having a maximum absorption wavelength within a wavelength range of 530 to 570 nm, a dye B having a maximum absorption wavelength within a wavelength range of 470 to 510 nm, and an ultraviolet absorber U having a maximum absorption wavelength within a wavelength range of 330 to 380 nm, A methacrylic resin composition satisfying the following formulas (1) to (3): 3 < (a × α) + (b × β) < 20 (1) 1.0 < (b × β) / (a ​​× α) < 7.0 (2) (In the formula, a represents the concentration of dye A in the methacrylic resin composition, and α represents the absorbance exhibited by the absorption maximum wavelength of dye A. b represents the concentration of dye B in the methacrylic resin composition, and β represents the absorbance at the maximum absorption wavelength of dye B. The units of a and b are ppm by mass. α and β are values ​​measured for a methyl methacrylate solution with a concentration of 1 ppm by mass at an optical path length of 20 mm. 0.1≦u≦1.0 (3) (In the formula, u represents the content of the ultraviolet absorber U in the methacrylic resin composition. The unit of u is mass%.)

2. The methacrylic resin composition according to claim 1, comprising a dye C having an absorption maximum wavelength within a wavelength range of 420 to 460 nm, and satisfying the following formula (4): 1≦c≦12 (4) (In the formula, c represents the concentration of dye C in the methacrylic resin composition. The unit of c is ppm by mass.)

3. 2. The methacrylic resin composition according to claim 1, wherein a is 10 to 100 ppm by mass and α is 0.04 to 0.

14.

4. The methacrylic resin composition according to claim 1, wherein the b is 80 to 330 ppm by mass and the β is 0.01 to 0.

11.

5. The methacrylic resin composition according to claim 1, wherein the dye A comprises at least one of an anthraquinone dye, an azo dye, and a pyrimidine dye.

6. The methacrylic resin composition according to claim 1 , wherein the dye B comprises at least one of a perinone dye and an azo dye.

7. 2. The methacrylic resin composition according to claim 1, wherein the ultraviolet absorber U comprises at least one of a benzotriazole-based ultraviolet absorber and a triazine-based ultraviolet absorber.

8. A color vision correcting lens obtained by molding the methacrylic resin composition according to any one of claims 1 to 7 into a lens shape.

9. An optical device for color vision correction, comprising the methacrylic resin composition according to any one of claims 1 to 7.