JP6226591B2 - Resin composition for optical material and method for producing the same - Google Patents

Description

  The present invention relates to a resin composition for optical materials and a method for producing the same, and further relates to an optical material obtained by molding the resin composition for optical materials.

  As a resin that is excellent in transparency and can be used for an optical material, a resin composition of an acrylic resin and a polycarbonate resin is known. For example, Patent Documents 1 to 3 disclose a resin composition of an acrylic resin and a polycarbonate resin as a resin composition that can be used for an optical material.

  However, these conventional resin compositions disclosed in Patent Documents 1 to 3 are not necessarily sufficiently small in phase difference, and cannot be used for optical materials that require a smaller phase difference.

JP-A-5-32846 Japanese Unexamined Patent Publication No. 2011-157412 JP 2012-51997 A

  Accordingly, the present inventors have intensively studied to develop a resin composition that has excellent transparency and weather resistance and can provide an optical material having a small phase difference, and as a result, has reached the present invention.

  That is, this invention is a resin composition for optical materials containing acrylic resin and polycarbonate-type resin, Comprising: The said polycarbonate-type resin has a viscosity average molecular weight of 10000-15000, The said acrylic resin 100 weight The content of the polycarbonate resin with respect to parts is 2 parts by weight or more and 10 parts by weight or less, and the resin composition for optical materials is provided.

  Since the resin composition of the present invention is excellent in transparency and weather resistance and has a sufficiently small phase difference, it is useful as a resin composition for optical materials.

  The resin composition for optical materials of the present invention (hereinafter sometimes simply referred to as “resin composition”) contains an acrylic resin and a polycarbonate resin.

<Acrylic resin>
The acrylic resin contained in the resin composition of the present invention is, for example, a polymer obtained by polymerizing an acrylic monomer. Examples of acrylic monomers include methacrylic acid, methacrylic acid ester, methacrylonitrile, acrylic acid, acrylic acid ester, acrylonitrile and the like. The acrylic resin may be a homopolymer (homopolymer) obtained by polymerizing a single acrylic monomer, or a copolymer obtained by copolymerizing two or more acrylic monomers. It may be a coalescence or a copolymer of 50% by weight or more of an acrylic monomer and 50% by weight or less of another monomer. In the present specification, the terms “acryl” and “methacryl” may be collectively referred to as “(meth) acryl”.

  Examples of the methacrylate ester include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, Methacrylic acid alkyl esters such as n-octyl methacrylate, n-nonyl methacrylate, isononyl methacrylate, decyl methacrylate, undecyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, lauryl methacrylate, methoxyethyl methacrylate, methacrylic acid Examples thereof include ethoxyethyl acid. Among these, methacrylic acid alkyl esters, and further methacrylic acid alkyl esters having an alkyl group having 1 to 8 carbon atoms are preferred, and methyl methacrylate is more preferred. Methacrylic acid esters may be used alone (homopolymer) or in combination of two or more (copolymer).

  Examples of the acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, heptyl acrylate, 2-ethylhexyl acrylate, Acrylic acid alkyl esters such as n-octyl acrylate, n-nonyl acrylate, isononyl acrylate, decyl acrylate, undecyl acrylate, n-amyl acrylate, isoamyl acrylate, lauryl acrylate, methoxyethyl acrylate, acrylic Examples thereof include ethoxyethyl acid. Among these, acrylic acid alkyl esters and further acrylic acid alkyl esters having an alkyl group having 1 to 8 carbon atoms are preferred, and methyl acrylate is more preferred.

  Other monomers include, for example, aromatic vinyl monomers, unsaturated nitriles, ethylenically unsaturated carboxylic acid hydroxyalkyl esters, ethylenically unsaturated carboxylic acid amides, ethylenically unsaturated acids other than acrylic acid and methacrylic acid, ethylene Unsaturated sulfonic acid ester, ethylenically unsaturated alcohol and ester thereof, ethylenically unsaturated ether, ethylenically unsaturated amine, ethylenically unsaturated silane compound, aliphatic conjugated diene and the like.

  Examples of the aromatic vinyl monomer include styrene, vinyl toluene, and α-methyl styrene.

  Examples of the unsaturated nitrile include acrylonitrile, α-chloroacrylonitrile, α-methoxyacrylonitrile, methacrylonitrile, vinylidene cyanide and the like.

  Examples of the ethylenically unsaturated carboxylic acid hydroxyalkyl ester include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxybutyl methacrylate.

  Examples of the ethylenically unsaturated carboxylic acid amide include acrylamide, methacrylamide, N-butoxymethyl acrylamide, N-butoxymethyl methacrylamide, N-butoxyethyl acrylamide, N-butoxyethyl methacrylamide, N-methoxymethyl acrylamide, N -Methoxymethylmethacrylamide, Nn-propoxymethylacrylamide, Nn-propoxymethylmethacrylamide, N-methylacrylamide, N-methylmethacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide N, N-diethylacrylamide, N, N-diethylmethacrylamide and the like.

  Examples of ethylenically unsaturated acids other than acrylic acid and methacrylic acid include ethylenically unsaturated carboxylic acids such as itaconic acid, fumaric acid, fumaric anhydride, maleic acid, maleic anhydride, vinyl sulfonic acid, and isoprene sulfonic acid. And ethylenically unsaturated sulfonic acid. The ethylenically unsaturated acid monomer may be neutralized with, for example, an alkali metal such as sodium or potassium, ammonia or the like.

  Examples of the ethylenically unsaturated sulfonate include alkyl vinyl sulfonate and alkyl isoprene sulfonate.

  Examples of the ethylenically unsaturated alcohol include allyl alcohol and methallyl alcohol. Examples of the ethylenically unsaturated alcohol ester include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl benzoate, allyl acetate, methallyl caproate, allyl laurate, allyl benzoate, vinyl alkylsulfonate, alkyl Examples include allyl sulfonate and vinyl aryl sulfonate.

  Examples of the ethylenically unsaturated ether include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, methyl allyl ether, and ethyl allyl ether.

  Examples of the ethylenically unsaturated amine include vinyldimethylamine, vinyldiethylamine, vinyldiphenylamine, allyldimethylamine, and methallyldiethylamine.

  Examples of the ethylenically unsaturated silane compound include vinyltriethylsilane, methylvinyldichlorosilane, dimethylallylchlorosilane, and vinyltrichlorosilane.

  Examples of the aliphatic conjugated diene include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-neopentyl-1,3-butadiene, and 2-chloro. -1,3-butadiene, 1,2-dichloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 2-bromo-1,3-butadiene, 2-cyano-1,3-butadiene, Substituted straight chain conjugated pentadienes, straight chain and side chain conjugated hexadienes, and the like.

(Methacrylic resin)
As the acrylic resin, a methacrylic resin is preferably used from the viewpoint of providing a resin composition for optical materials having excellent hardness, weather resistance, transparency, and the like. A methacrylic resin is a polymer obtained by polymerizing a monomer mainly composed of a methacrylic acid ester. For example, a polyalkyl methacrylate which is a homopolymer of a methacrylic acid ester, a copolymer of two or more methacrylic acid esters Examples thereof include a copolymer and a copolymer of 50% by weight or more of a methacrylic acid ester and another monomer other than 50% by weight or less of a methacrylic acid ester.
In the case of a copolymer of a methacrylic acid ester and another monomer other than the methacrylic acid ester, the methacrylic acid ester is usually 99.9% by weight or less based on the total amount of the monomers, and other single amounts other than this. Body is 0.1% by weight or more, preferably methacrylic acid ester is 70% by weight or more, other monomer is 30% by weight or less, more preferably methacrylic acid ester is 90% by weight or more. The weight is 10% by weight or less.

  Examples of the methacrylic acid ester used for the methacrylic resin include the above-mentioned methacrylic acid esters, and methacrylic acid alkyl esters are preferably used.

  As monomers other than methacrylic acid ester, for example, acrylic acid ester, aromatic vinyl monomer, unsaturated nitrile, ethylenically unsaturated carboxylic acid hydroxyalkyl ester, ethylenically unsaturated carboxylic acid amide, ethylenically unsaturated Examples include acids, ethylenically unsaturated sulfonic acid esters, ethylenically unsaturated alcohols and esters thereof, ethylenically unsaturated ethers, ethylenically unsaturated amines, ethylenically unsaturated silane compounds, and aliphatic conjugated dienes. Among these, acrylic acid esters are preferable. Monomers other than methacrylic acid esters may be used alone or in combination of two or more.

Examples of the acrylic acid ester used in the methacrylic resin include the above-mentioned acrylic acid esters, and alkyl acrylates are preferably used.
Aromatic vinyl monomer, unsaturated nitrile, ethylenically unsaturated carboxylic acid hydroxyalkyl ester, ethylenically unsaturated carboxylic acid amide, ethylenically unsaturated sulfonic acid ester, ethylenically unsaturated alcohol, ethylenic Examples of the unsaturated alcohol ester, ethylenically unsaturated ether, ethylenically unsaturated amine, ethylenically unsaturated silane compound and aliphatic conjugated diene include the compounds exemplified as the other monomers in the acrylic resin.
Examples of the ethylenically unsaturated acid used in the methacrylic resin include the compounds exemplified as the ethylenically unsaturated acid in the acrylic resin, acrylic acid and methacrylic acid.

  The acrylic resin can be obtained by a method of polymerizing the above monomers. Examples of the polymerization method include an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a liquid injection polymerization method (cast polymerization method), and the like. The polymerization is usually initiated by light irradiation or a polymerization initiator. Examples of the polymerization initiator include azo initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), lauroyl peroxide, benzoyl peroxide, and the like. It is preferable to use a polymerization initiator such as a peroxide-based initiator or a redox-based initiator in which an organic peroxide and an amine are combined. When using a polymerization initiator, it is used in a proportion of usually 0.01 to 1 part by weight, preferably 0.01 to 0.5 part by weight, based on 100 parts by weight of the monomer. Further, a chain transfer agent for controlling the molecular weight (a linear or branched alkyl mercaptan compound such as methyl mercaptan, n-butyl mercaptan, t-butyl mercaptan, etc.), a crosslinking agent or the like may be added.

(Acrylic resin with a ring structure in the molecular chain)
The acrylic resin may have a ring structure in the molecular chain from the viewpoint of improving the heat resistance of the obtained optical material resin composition. Examples of the ring structure include a lactone ring structure, a glutaric anhydride structure, a glutaric imide structure, a maleic anhydride structure, and a maleimide structure.

An acrylic resin having a lactone ring structure in the molecular chain can be obtained, for example, by subjecting a methacrylic resin having a hydroxyl group and an ester group in the molecular chain to a cyclocondensation reaction in the molecule. As an acrylic resin having a hydroxyl group and an ester group in the molecular chain, for example, a monomer mixture containing monomers such as methacrylic acid ester, acrylic acid ester and 2- (hydroxyalkyl) alkyl acrylate is polymerized. What can be obtained can be mentioned. Examples of the methacrylic acid ester and acrylic acid ester include the above-mentioned methacrylic acid esters and acrylic acid esters.
Cyclocondensation is carried out, for example, by heating the acrylic resin, and the hydroxyl group and ester group present in the molecular chain of the acrylic resin are cyclized and condensed to produce a lactone ring structure. System resin can be obtained. In such a cyclocondensation reaction, an organic phosphorus compound is usually used as a catalyst.

  An acrylic resin having a glutaric anhydride structure in the molecular chain is, for example, a homopolymer of methyl methacrylate, a copolymer of methyl methacrylate and methacrylic acid, a copolymer of methyl methacrylate and acrylic acid, or The copolymer of methyl methacrylate, methacrylic acid and acrylic acid is usually 150 to 350 ° C., preferably 220 to 320 ° C. in the presence of a basic compound such as sodium hydroxide, potassium hydroxide or sodium methylate. It can be obtained by heat treatment for modification.

  An acrylic resin having a glutarimide structure in the molecular chain is, for example, a homopolymer of methyl methacrylate, a copolymer of methyl methacrylate and methacrylic acid, a copolymer of methyl methacrylate and acrylic acid, or It can be obtained by modifying a copolymer of methyl methacrylate, methacrylic acid and acrylic acid by heat treatment usually in the range of 150 to 350 ° C., preferably 220 to 320 ° C. in the presence of ammonia or a primary amine. it can.

  An acrylic resin having a maleic anhydride structure in the molecular chain can be obtained, for example, by copolymerizing methyl methacrylate and maleic anhydride. The acrylic resin having a maleimide structure in the molecular chain is obtained by copolymerizing, for example, methyl methacrylate and maleimide, N-substituted maleimide N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-benzylmaleimide, etc. Can be obtained at

(Viscosity average molecular weight of acrylic resin)
The acrylic resin preferably has a viscosity average molecular weight of 50,000 to 300,000, more preferably has a viscosity average molecular weight of 80000 to 200,000, and more preferably has a viscosity average molecular weight of 100,000 to 150,000.

The viscosity average molecular weight (Mv) of the acrylic resin is obtained using the following formula (1).
lnMv = {ln [η] −ln (4.8 × 10 ⁻⁵ )} / 0.8 (1)
In the formula (1), [η] represents the intrinsic viscosity, and is obtained as a positive value satisfying the following formula (2) from the viscosity number VN measured according to ISO 1628-6.
VN = [η] + 0.4 × [η] ² (2)

  Among these acrylic resins, polymethyl methacrylate, which is a homopolymer of methyl methacrylate, 50% by weight or more, usually 99.9% by weight or less methyl methacrylate, and 50% by weight or less, usually 0.1% A copolymer with a methacrylic acid ester or acrylic acid ester other than methyl methacrylate by weight percent or more is particularly preferred. A copolymer of 50% by weight or more of methyl methacrylate and 50% by weight or less of (meth) acrylic acid ester other than methyl methacrylate is based on the total amount of methyl methacrylate and the (meth) acrylic acid ester. Copolymer weight obtained by polymerizing a monomer mixture containing methyl methacrylate in a proportion of 50% by weight or more and (meth) acrylic acid ester other than methyl methacrylate in a proportion of 50% by weight or less It is a coalescence. In this monomer mixture, methyl methacrylate is preferably contained in a proportion of 70 to 99.9% by weight, more preferably 90 to 99.9% by weight. In this mixture, (meth) acrylic acid esters other than methyl methacrylate are preferably contained in a proportion of 30 to 0.1% by weight, more preferably in a proportion of 10% to 0.1% by weight. The

<Polycarbonate resin>
Examples of the polycarbonate resin contained in the resin composition of the present invention include those obtained by reacting a dihydric phenol and a carbonylating agent by a method such as an interfacial polycondensation method or a melt transesterification method. Examples of the polycarbonate resin include those obtained by polymerizing a carbonate prepolymer by a solid phase transesterification method or the like. Examples of the polycarbonate resin include those obtained by polymerizing a cyclic carbonate compound by a ring-opening polymerization method.

  Examples of the dihydric phenol include hydroquinone, resorcinol, 4,4′-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, bis {(4-hydroxy-3,5-dimethyl) phenyl} methane, 1,1- Bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A), 2,2-bis { (4-hydroxy-3-methyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dimethyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dibromo) ) Phenyl} propane, 2,2-bis {(3-isopropyl-4-hydroxy) phenyl} propane, 2,2-bis {(4- Hydroxy-3-phenyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) -3,3-dimethylbutane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -4 -Methylpentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3 5-trimethylcyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis {(4-hydroxy- -Methyl) phenyl} fluorene, α, α'-bis (4-hydroxyphenyl) -o-diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene, α, α'-bis ( 4-hydroxyphenyl) -p-diisopropylbenzene, 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane, 4,4′-dihydroxydiphenylsulfone, 4,4′-dihydroxydiphenylsulfoxide, 4, Examples include 4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenyl ketone, 4,4′-dihydroxydiphenyl ether, and 4,4′-dihydroxydiphenyl ester. These may be used alone or in combination of two or more.

  Among these dihydric phenols, bisphenol A, 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4 -Hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) -3,3-dimethylbutane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-Hydroxyphenyl) -3,3,5-trimethylcyclohexane and α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene are preferred. In particular, use of bisphenol A alone, bisphenol A, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis {(4-hydroxy-3-methyl) phenyl } Combination with at least one selected from the group consisting of propane and α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene is preferred.

  Examples of the carbonylating agent include carbonyl halides (such as phosgene), carbonate esters (such as diphenyl carbonate), and haloformates (such as dihaloformates of dihydric phenols). These may be used alone or in combination of two or more.

(Viscosity average molecular weight of polycarbonate resin)
The polycarbonate resin has a viscosity average molecular weight of 10,000 to 15000, preferably 11000 to 14000, more preferably 12000 to 14,000. The viscosity average molecular weight (Mv) of the polycarbonate-based resin can be calculated from the intrinsic viscosity [η] of the 20 ° C. methylene chloride solution as a value satisfying the following Schnell formula.
[Η] = 1.23 × 10 ⁻⁴ Mv ^0.83

<Resin composition for optical material>
The resin composition for an optical material of the present invention contains the polycarbonate resin at a ratio of 2 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the acrylic resin. When the content of the polycarbonate resin is less than 2 parts by weight, the phase difference tends to increase. When the content of the polycarbonate-based resin exceeds 10 parts by weight, the transparency tends to decrease. The content of the polycarbonate resin relative to 100 parts by weight of the acrylic resin is preferably 3 parts by weight or more, more preferably 4 parts by weight or more, preferably 9 parts by weight or less, more preferably 8 parts by weight or less, and still more preferably. 6 parts by weight or less.

  In addition to the acrylic resin and the polycarbonate resin, various commonly used additives may be added to the resin composition for an optical material of the present invention as long as the effects of the present invention are not impaired. . Examples of additives include stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, colorants, foaming agents, lubricants, mold release agents, antistatic agents, flame retardants, polymerization inhibitors, flame retardant aids, Examples include reinforcing agents. These may be used alone or in combination of two or more. When the additive is added, the content thereof is preferably about 0.005 to 30% by weight with respect to the resin composition.

The resin composition of the present invention is transparent when visually observed. As a quantitative index of transparency, for example, the resin composition of the present invention is molded into a plate-like molded body having a thickness of 3 mm to form a test piece, and the test piece is measured in accordance with JIS K7361-1. And total light transmittance (Tt). Thus, the total light transmittance (Tt) calculated | required becomes like this. Preferably it is 87% or more, More preferably, it is 90% or more.
As another index of transparency, haze of the plate-like molded body measured in accordance with JIS K7136 can be mentioned. The haze thus determined is preferably 1.5% or less, more preferably 1% or less.

The resin composition of the present invention is characterized by a small phase difference. Examples of the retardation index include an in-plane retardation (Re) measured with a light beam of 590 nm at 25 ° C. when molded into the plate-shaped molded body. The in-plane retardation (Re) measured in this way is preferably 5 nm or less, more preferably 4.8 nm or less.
As another phase difference index, there is also a thickness direction phase difference (Rth) measured with a light beam of 590 nm at 25 ° C. when molded into the plate-shaped molded body.

  The resin composition of the present invention is also excellent in weather resistance and does not turn yellow even when left outdoors for one month, for example.

<Method for producing resin composition>
As a manufacturing method of the resin composition for optical materials which concerns on this invention, the method of melt-kneading acrylic resin and polycarbonate-type resin is mentioned, for example. The melt-kneading is usually performed at a temperature of 180 to 300 ° C. and a shear rate of 10 to 1000 sec ⁻¹ . In the melt-kneading, the polycarbonate resin is used in a proportion of, for example, 2 parts by weight or more and 10 parts by weight or less, preferably 3 parts by weight or more, more preferably 4 parts by weight or more with respect to 100 parts by weight of the acrylic resin. , Preferably 9 parts by weight or less, more preferably 8 parts by weight or less, and still more preferably 6 parts by weight or less.

When the temperature at the time of melt kneading is less than 180 ° C., the polycarbonate resin used may not be sufficiently melted. On the other hand, when the temperature at the time of melt kneading exceeds 300 ° C., the acrylic resin or polycarbonate resin to be used may be thermally decomposed. Furthermore, when the shear rate during melt kneading is less than 10 sec ⁻¹ , the acrylic resin and the polycarbonate resin may not be sufficiently kneaded. On the other hand, when the shear rate at the time of melt kneading exceeds 1000 sec ⁻¹ , the acrylic resin or polycarbonate resin used may be decomposed.
In order to obtain a resin composition in which each component is more uniformly mixed, the melt kneading is preferably performed at a temperature of 190 to 300 ° C., more preferably 200 to 300 ° C., preferably 20 to 700 sec ⁻¹ , and more. Preferably, it is carried out at a shear rate of 50 to 500 sec- ¹ .

  As an apparatus used for melt kneading, a normal mixer or kneader can be used. Specific examples include a single-screw kneader, a twin-screw kneader, a multi-screw extruder, a Henschel mixer, a Banbury mixer, a kneader, and a roll mill. Further, when the shear rate is increased within the above range, a high shear processing device or the like may be used. As a high shear processing apparatus, for example, “NHSS2-28” manufactured by Niigata Machine Techno Co., Ltd. is commercially available. Melt-kneading may be performed in an inert gas atmosphere such as nitrogen gas, argon gas, helium gas, if necessary.

  When the resin composition of the present invention contains the above-mentioned additive, the additive may be added in advance to at least one of the acrylic resin and the polycarbonate resin, or may be added at the time of melt kneading, You may add before or after melt-kneading.

  The resin composition for an optical material of the present invention thus obtained has excellent transparency and weather resistance and has a small phase difference, and therefore can be suitably used for an optical material.

<Optical material>
The resin composition for an optical material of the present invention is molded into a desired shape, has excellent transparency and weather resistance, and is used as an optical material having a small phase difference. Examples of such an optical material include an optical film, a light guide plate, a display front plate, and a signboard.
In the molding process, the resin composition melt-kneaded by the above-described manufacturing method may be supplied to a molding machine while being heated and melted to be molded. Alternatively, the obtained resin composition may be formed into pellet-shaped resin pellets, which are heated and melted by a molding machine such as an injection molding machine, a hydraulic press, or an extrusion molding machine, and then molded. The molding temperature is usually about 150 to 350 ° C, preferably about 180 to 300 ° C, more preferably about 200 to 300 ° C.

  Since the resin composition of the present invention has a sufficiently small phase difference, the phase difference of an optical material to be obtained, for example, an optical film, becomes small even when it is molded by extrusion molding in which the phase difference tends to increase.

<Optical film>
When producing an optical film as an optical material comprising the resin composition of the present invention, for example, an extrusion molding method in which the resin composition of the present invention is supplied to an extrusion molding machine, heated and melted, and then extruded from a die. Can be manufactured. As a method of extruding from the die, a normal method such as a feed block method or a multi-manifold method is employed.

  The heat-melted resin composition extruded from a die is usually formed into a film by being brought into close contact with a roll or a belt. The number, arrangement, and material of the rolls and belts at this time are not particularly limited. For example, the surface shape of a roll or belt can be obtained by passing a resin composition extruded from a die by heating and melting between two metal rolls, or by passing the resin composition in contact with a metal roll and a metal belt. Is preferable in terms of improving the surface accuracy of the film surface and improving the surface treatment. As two metal rolls, a metal roll having elasticity and a metal roll having no elasticity are used, and a resin composition in a heated and melted state immediately after being extruded from a die is sandwiched between these metal rolls, and resin The method of passing the composition while contacting the surfaces of both metal rolls is suitable for obtaining a film in which distortion during molding is reduced and strength and heat shrinkable anisotropy are reduced. The metal roll having elasticity includes, for example, a shaft roll and a cylindrical metal thin film that is arranged so as to cover the outer peripheral surface of the shaft roll and that contacts the molten resin. Among them, the one in which a fluid whose temperature is controlled, such as water or oil, is enclosed, and the one in which a metal belt is wound around the surface of a rubber roll.

  Thus, the thickness of the optical film obtained is 20-200 micrometers normally, Preferably it is 20-180 micrometers, More preferably, it is 20-170 micrometers. The content of the polycarbonate resin in the optical film having such a thickness is 2 parts by weight or more and 10 parts by weight or less, preferably 3 parts by weight or more, more preferably 4 parts by weight with respect to 100 parts by weight of the acrylic resin. Part or more, preferably 9 parts by weight or less, more preferably 8 parts by weight or less, and still more preferably 6 parts by weight or less.

<Polarizing plate>
Since the optical film made of the resin composition of the present invention is excellent in transparency and has a small retardation, for example, in a polarizing plate, it is suitably used as a protective film laminated on at least one surface of a polarizing film. The protective film is bonded to the polarizing film using, for example, an adhesive.

(Polarizing film)
As the polarizing film, for example, a film obtained by adsorbing and orienting a dichroic dye on a polyvinyl alcohol-based resin film can be used. As the dichroic dye, iodine or a dichroic organic dye is used. Such a polarizing film has an absorption axis based on a dichroic dye that is adsorbed and oriented, and the dichroic dye absorbs a polarization component parallel to the absorption axis and transmits an orthogonal polarization component. Can do. A polarizing film having iodine adsorbed and oriented on a polyvinyl alcohol resin film is referred to as an iodine polarizing film, and a polarizing film having a dichroic organic dye adsorbed and oriented on a polyvinyl alcohol resin film is referred to as a dye polarizing film. Has been.

  The polyvinyl alcohol resin constituting the polarizing film can be obtained by saponifying the polyvinyl acetate resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and other monomers copolymerizable therewith is used. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The polyvinyl alcohol resin may be modified, for example, polyvinyl formal, polyvinyl acetal, polyvinyl butyral and the like modified with aldehydes may be used.

  A polarizing film is usually a humidity adjusting step for adjusting the moisture of the polyvinyl alcohol-based resin film, a uniaxial stretching step for uniaxially stretching the polyvinyl alcohol-based resin film, and a dichroic dyeing of the polyvinyl alcohol-based resin film with a dichroic dye. It is manufactured through a dyeing process for adsorbing and orienting the dye, a boric acid treatment process for treating the polyvinyl alcohol resin film on which the dichroic dye is adsorbing and orienting with an aqueous boric acid solution, and a washing process for washing off the boric acid aqueous solution. The uniaxial stretching step can be performed before or after the dyeing step, or can be performed during the dyeing step. When performing a uniaxial stretching process after a dyeing process, it can also be performed during the boric acid treatment process after a dyeing process. The uniaxial stretching step may be performed in multiple steps. The method of uniaxial stretching may be a method of stretching uniaxially between rolls having different peripheral speeds, or a method of stretching uniaxially using a hot roll. Moreover, the dry-type extending | stretching which extends | stretches in air | atmosphere may be sufficient, and the wet extending | stretching which extends | stretches in the state swollen with the solvent may be sufficient. The draw ratio is usually about 4 to 8 times. The thickness of the finally obtained polarizing film is preferably about 1 to 50 μm, for example.

(Protective film)
A protective film is usually bonded to one side or both sides of the polarizing film. The optical film made of the resin composition of the present invention is used as a protective film bonded (laminated) to the polarizing film, and is laminated on at least one surface of the polarizing film, for example.

When the protective film is laminated on both sides of the polarizing film, the protective film laminated on the polarizing film may be an optical film made of the resin composition of the present invention. The protective film laminated on one side is an optical film made of the resin composition of the present invention, and the protective film laminated on the other side is a protective film made of a transparent resin other than the resin composition of the present invention. May be.
Examples of the film made of a transparent resin other than the resin composition of the present invention include acrylic resins (for example, methacrylic resins), chain polyolefin resins (for example, polypropylene resins), cyclic polyolefin resins, polychlorinated resins. Cellulose resins such as vinyl resins and cellulose acetate resins (for example, triacetyl cellulose, diacetyl cellulose, etc.), styrene resins, acrylonitrile / butadiene / styrene copolymer resins, acrylonitrile / styrene copolymer resins, polyvinyl acetate Resin, polyvinylidene chloride resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polysulfone resin , Polyethersulfone resins, polyarylate resins, polyamide-imide resin, a protective film made of polyimide resin and the like. The thickness of these protective films is usually 20 to 200 μm, preferably 20 to 170 μm.

  As a film made of a transparent resin other than the resin composition of the present invention, a retardation film such as a wave plate viewing angle compensation film such as a quarter wave plate or a half wave plate may be used. By laminating such a retardation film, the number of films used can be reduced as compared with the case where a retardation film is used independently of a polarizing plate. Therefore, it is possible to reduce the weight and thickness of a liquid crystal display device using a polarizing plate. As a retardation film such as a wave plate or a viewing angle compensation film, a conventionally known film can be used. The retardation film is, for example, a polycarbonate resin, a polyvinyl alcohol resin, a polystyrene resin, an acrylic resin, a polyolefin resin (eg, polypropylene), a cyclic polyolefin resin, a polyarylate resin, a polyimide resin, or a polyamide resin. It can be obtained by stretching a film made of a resin or the like by an appropriate method such as uniaxial or biaxial. The retardation film may be a birefringent film in which the refractive index in the thickness direction of the film is controlled by applying a shrinkage force and / or stretching force under adhesion with the heat-shrinkable film.

(Lamination of polarizing film, optical film and protective film)
In order to laminate an optical film made of the resin composition of the present invention, another protective film, or the like on a polarizing film, it is usually sufficient to use an adhesive. Prior to bonding, at least one of the bonding surfaces of each film is preferably subjected to corona discharge treatment, plasma irradiation treatment, electron beam irradiation treatment, and other surface activation treatment.

  The adhesive can be arbitrarily selected and used from those that exhibit adhesive strength to each member. A typical example is an active energy ray-curable adhesive containing a component that is cured by irradiation with an active energy ray.

  When an active energy ray-curable adhesive is used, components that cure by irradiation of active energy rays constituting the active energy ray (hereinafter sometimes simply referred to as “curable components”) include epoxy compounds, oxetane compounds, acrylics. System compounds and the like. When a cationically polymerizable compound such as an epoxy compound or an oxetane compound is used, a cationic polymerization initiator is blended. When a radical polymerizable compound such as an acrylic compound is used, a radical polymerization initiator is blended. Among them, an adhesive having an epoxy compound as one of the curable components is preferable, and an adhesive having an alicyclic epoxy compound in which an epoxy group is directly bonded to a saturated hydrocarbon ring as one of the curable components is particularly preferable. . It is also effective to use an oxetane compound in combination.

  Epoxy compounds can be easily obtained as commercial products. For example, “Epicoat” series sold by Japan Epoxy Resin Co., Ltd. and “Epicron” sold by DIC Corporation, respectively. Series, "Epototo" series sold by Toto Kasei Co., Ltd., "Adeka Resin" series sold by ADEKA Co., Ltd., "Denacol" series sold by Nagase ChemteX Corporation, and sold by Dow Chemical "Dow Epoxy" series, "Tepic" sold by Nissan Chemical Industries, Ltd.

  An alicyclic epoxy compound in which an epoxy group is directly bonded to a saturated hydrocarbon ring can also be easily obtained as a commercial product, for example, sold under the trade name by Daicel Chemical Industries, Ltd. Examples include the "Celoxide" series and the "Cyclomer" series, and the "Syracure" series sold by Dow Chemical.

  Oxetane compounds can also be easily obtained as commercial products. For example, “Aron Oxetane” series sold by Toagosei Co., Ltd. and “ETERNACOLL” sold by Ube Industries, Ltd. ”Series.

  Cationic polymerization initiators can also be easily obtained on the market, for example, under the trade name, “Kayarad” series sold by Nippon Kayaku Co., Ltd., and sold by Union Carbide, Inc. Photo acid generators "CPI" series sold by SyraCure ", San Apro Co., Ltd. Photo acid generators" TAZ "," BBI "and" DTS "sold by Midori Chemical Co., Ltd., from ADEKA Corporation Examples include the “Adekaoptomer” series sold and the “RHODORSIL” series sold by Rhodia.

  The active energy ray-curable adhesive can contain a photosensitizer as necessary. By using a photosensitizer, the reactivity is improved, and the mechanical strength and adhesive strength of the cured product layer can be further improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, anthracene compounds, halogen compounds, and photoreducible dyes.

  Moreover, various additives can be mix | blended with an active energy ray hardening adhesive in the range which does not impair the adhesiveness. Examples of the additive include an ion trap agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, and an antifoaming agent. Furthermore, a curable component that cures by a reaction mechanism different from cationic polymerization can be blended within a range that does not impair the adhesion.

  As described above, the active energy ray-curable adhesive described above is applied to the bonding surface of the optical film or the bonding surface of the polarizing film, and after bonding both films through the coating layer, the active energy ray is applied thereto. It is cured by irradiation and becomes an adhesive layer that joins the polarizing film and the optical film. Moreover, it is apply | coated to the bonding surface of a polarizing film, or the bonding surface of a protective film, and after bonding both films through the coating layer, it is hardened by irradiating an active energy ray there, and a polarizing film and a protective film It becomes the adhesive bond layer which joins. The adhesive for forming the adhesive layer and the adhesive for forming the adhesive layer may be the same composition or different compositions, but irradiation with active energy rays for curing both Are preferably performed simultaneously.

  The active energy ray used for curing the active energy ray-curable adhesive may be, for example, X-ray having a wavelength of 1 to 10 nm, ultraviolet light having a wavelength of 10 to 400 nm, visible light having a wavelength of 400 to 800 nm, and the like. Among these, ultraviolet rays are preferably used in view of ease of use and ease of preparation of active energy ray-curable adhesive, stability and curing performance. As an ultraviolet light source, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp or the like having a light emission distribution at a wavelength of 400 nm or less may be used. it can.

  The thickness of the adhesive layer obtained using the active energy ray-curable adhesive is usually about 1 to 50 μm, and particularly preferably in the range of 1 to 10 μm.

  The polarizing plate thus obtained is obtained by laminating an optical film made of the resin composition for an optical material of the present invention on at least one side of a polarizing film made of a polyvinyl alcohol-based resin. An optical film made of the resin composition for an optical material of the present invention is laminated, and a protective film made of another transparent resin is laminated on the other surface.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to these Examples.
In addition, resin used by the Example and the comparative example is as follows.
Acrylic resin: Sumipex (registered trademark) MHF (manufactured by Sumitomo Chemical Co., Ltd.)
Polycarbonate resin (PC resin 1): SD2201W (manufactured by Sumika Stylon Polycarbonate Co., Ltd., viscosity average molecular weight 13000)
Polycarbonate resin (PC resin 2): Caliber 301-10 (manufactured by Sumika Stylon Polycarbonate Co., Ltd., viscosity average molecular weight 22000)

Evaluation of physical properties performed in Examples and Comparative Examples is as follows.
<Total light transmittance (Tt)>
Using a transmittance meter (HR-100, manufactured by Murakami Color Research Laboratory Co., Ltd.), the total light transmittance (Tt) was measured according to JIS K7361-1. The larger this value is, the easier it is to transmit light and the higher the transparency.

<Haze>
Using the above HR-100, haze was measured according to JIS K7136. The smaller this value, the higher the transparency.

<Weather resistance>
The molded body (optical material) was left outdoors for one month, then visually observed and evaluated according to the following criteria.
○: When there is no change △: When slightly yellowing ×: When yellowing

<Phase difference>
The molded body was cut into a predetermined size (50 × 50 × 3 mm) to prepare a test piece. About the obtained test piece, the refractive index (nx) in the x-axis direction at 590 nm and the refractive index (ny) in the y-axis direction were measured with a “retardation film / optical material inspection apparatus RETS-100” manufactured by Otsuka Electronics Co., Ltd. The refractive index (nz) in the z-axis direction was measured, and the in-plane retardation (Re) and the thickness direction retardation (Rth) were calculated from the obtained measured values using the following equations. In the formula, d indicates the thickness (nm) of the test piece, and nx, ny, and nz indicate the refractive indexes in the x-axis direction, the y-axis direction, and the z-axis direction, respectively.
Re (nm) = (nx−ny) × d
Rth (nm) = {(nx + ny) / (2-nz)} × d

<Heat resistance>
The molded body was cut into a size of 20 mm × 20 mm to prepare a test piece. About the obtained test piece, based on JIS K7206 B50 method, Vicat softening temperature (VST) was measured under the conditions of a load of 50 N and a heating rate of 50 ° C./hour.

<Fluidity>
The melt flow rate (MFR) of the molded body was measured under the conditions of a temperature of 230 ° C. and a load of 3.8 kg in accordance with JIS K7210.

<Mechanical properties>
The molded body was subjected to a tensile test in accordance with JIS K7162, and the strength, elastic modulus, and elongation were measured. Further, the molded body was subjected to a bending test in accordance with JIS K7171, and the strength, elastic modulus, and deflection were measured.

Example 1
100 parts by weight of Sumipex (registered trademark) MHF and 3.1 parts by weight of SD2201W were dry blended, and this was kneaded with a kneader (manufactured by Nippon Steel Works, TEX-30) at 250 ° C. and 200 rpm. By kneading, a resin composition was obtained.
The obtained resin composition was injection-molded at 250 ° C. with an injection molding machine (manufactured by Toshiba Machine Co., Ltd., IS-130) to obtain a molded body (optical material) having a thickness of 3 mm. The obtained molded product was measured for the above physical properties (total light transmittance, haze, weather resistance, birefringence, heat resistance, fluidity, and mechanical properties). The results are shown in Table 1.

(Examples 2 and 3 and Comparative Examples 1 to 3)
Resin compositions were obtained in the same manner as in Example 1 except that the resins listed in Table 1 were used in the proportions listed in Table 1.
A molded product having a thickness of 3 mm was obtained in the same procedure as in Example 1 except that the obtained resin composition was used. About each obtained molded object, said physical property was measured. The results are shown in Table 1.

(Reference Example 1)
A molded product having a thickness of 3 mm was obtained in the same procedure as in Example 1 except that an acrylic resin (Sumipex (registered trademark) MHF) was used alone instead of the resin composition obtained in Example 1. About the obtained molded object, said physical property was measured. The results are shown in Table 1.

(Reference Example 2)
A molded body having a thickness of 3 mm was obtained in the same procedure as in Example 1 except that the polycarbonate resin (SD2201W) was used alone instead of the resin composition obtained in Example 1. About the obtained molded object, said physical property was measured. The results are shown in Table 1.

  As shown in Table 1, it can be seen that the molded bodies obtained in Examples 1 to 3 were excellent in transparency and did not turn yellow even when left outdoors for one month. Furthermore, the molded bodies obtained in Examples 1 to 3 have a small phase difference, and in particular, the thickness direction retardation (Rth) is smaller than the molded bodies obtained in Comparative Examples 1 and 2. Moreover, it turns out that it is smaller than the case of acrylic resin independent use (reference example 1).

Example 4
The resin composition obtained in Example 1 was put into a 65 mmφ single screw extruder and melted. An optical film having a thickness of 147 μm is obtained by extruding through a T-shaped die having a set temperature of 260 ° C. to form a film, and sandwiching the film between a pair of metal rolls having a smooth surface. It was. This optical film had a total light transmittance (Tt) of 92% and a haze of 0.2%. The weather resistance was “◯”. The in-plane retardation (Re) was 0.6 nm and the thickness direction retardation (Rth) was −1 nm.

(Example 5)
An optical film having a thickness of 155 μm was obtained in the same procedure as in Example 4 except that the resin composition obtained in Example 2 was used. This optical film had a total light transmittance (Tt) of 92% and a haze of 0.2%. The weather resistance was “◯”. The in-plane retardation (Re) was 0.5 nm and the thickness direction retardation (Rth) was 1.3 nm.

(Example 6)
An optical film having a thickness of 160 μm was obtained in the same procedure as in Example 4 except that the resin composition obtained in Example 3 was used. This optical film had a total light transmittance (Tt) of 92% and a haze of 0.2%. The weather resistance was “◯”. The in-plane retardation (Re) was 0.8 nm, and the thickness direction retardation (Rth) was 3.2 nm.

(Comparative Example 4)
An optical film having a thickness of 161 μm was obtained in the same procedure as in Example 4 except that the resin composition obtained in Comparative Example 2 was used and the set temperature of the T-shaped die was set to 250 ° C. The obtained optical film had a total light transmittance (Tt) of 92% and a haze of 0.2%. The weather resistance was “Δ”. The in-plane retardation (Re) was 2.2 nm and the thickness direction retardation (Rth) was 6.6 nm.

Claims (9)

Laminated on at least one side of the polarizing film,
The in-plane retardation (Re) measured with a light beam of 590 nm is 0.8 nm or less,
The protective film which consists of a resin composition for optical materials which contains the polycarbonate-type resin which has a viscosity average molecular weight of 10000-15000 with respect to 100 weight part of acrylic resins in the ratio of 2 to 10 weight part. The protective film according to claim 1, wherein the content of the polycarbonate resin is 8 parts by weight or less with respect to 100 parts by weight of the acrylic resin. The protective film according to claim 1, wherein a content of the polycarbonate resin is 6 parts by weight or less with respect to 100 parts by weight of the acrylic resin. The protective film according to claim 1, wherein the optical material resin composition is extruded. The protective film according to claim 1, thickness of 20Myuemu～200myuemu. The protective film according to any one of claims 1 to 5, the thickness direction retardation measured in light of 590 nm (Rth) is below 3.2nm or -1 nm. The protective film according to any one of the resin composition for optical material consisting only of claims 1-6. A protective film having an in-plane retardation (Re) measured with a light beam of 590 nm of 0.8 nm or less is laminated on at least one surface of the polarizing film ,
The said protective film consists of a resin composition for optical materials which contains the polycarbonate-type resin which has a viscosity average molecular weight of 10,000-15000 with respect to 100 weight part of acrylic resins in the ratio of 2 weight part or more and 10 weight part or less. A characteristic polarizing plate. The polarizing plate according to claim 8 , wherein the protective film is laminated on one surface of the polarizing film, and a protective film made of a transparent resin different from the protective film is laminated on the other surface.