JP2012176495A - Resin plate, scratch-resistant resin plate using the same, protective plate for display and protective plate for touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin plate which can be used as a resin substrate in a scratch-resistant resin plate and achieves a scratch-resistant resin plate excellent in transparency, surface hardness, impact resistance and color unevenness resistance, and to provide the scratch-resistant resin plate, a protective plate for display and a protective plate for touch panel each using the resin plate.SOLUTION: The resin plate is used as the resin substrate in the scratch-resistant resin plate and can be formed by laminating a layer (B) formed of a resin composition at least on one surface of a layer (A) formed of a polycarbonate resin. The resin composition contains a styrene-butadiene copolymer at a rate of 1 to 20 wt.% based on total 100 wt.% of an alkyl methacrylate-styrene copolymer and a styrene-butadiene copolymer. The scratch-resistant resin plate, the protective plate for display and the protective plate for touch panel each using the resin plate are also provided.

Description

  The present invention relates to a resin plate used as a resin substrate in an abrasion-resistant resin plate, an abrasion-resistant resin plate using the resin plate as a resin substrate, a display protective plate and a touch panel protective plate made of the scratch-resistant resin plate. About.

  Conventionally, an abrasion-resistant resin plate formed by forming a cured film on at least one surface of a resin substrate is known. As the scratch-resistant resin plate, a resin plate in which an acrylic resin layer is laminated on at least one surface of a polycarbonate resin layer is used as a resin substrate, and a cured film is formed on the surface of the acrylic resin layer of the resin substrate. is there.

Scratch-resistant resin plates are often used as protective plates for displays and touch panels. Therefore, transparency, surface hardness, impact resistance, etc. are required, and in order to ensure visibility, it is due to light interference. Color unevenness resistance and the like that hardly cause color unevenness (interference fringes) are also required.
However, the conventional scratch-resistant resin plate is not particularly satisfactory in uneven color resistance among the required performance.

  In order to solve this problem, Patent Document 1 discloses that an acrylic resin layer laminated on at least one surface of a polycarbonate resin layer is composed of a copolymer of methyl methacrylate and styrene, thereby suppressing the occurrence of interference fringes. It is described to do.

  However, the scratch-resistant resin plate described in Patent Document 1 is not sufficient in impact resistance. Therefore, there has been a demand for development of a scratch-resistant resin plate that is excellent in all of transparency, surface hardness, impact resistance, and color unevenness resistance.

JP 2010-44163 A

  An object of the present invention is to provide a resin plate that can be used as a resin substrate for a scratch-resistant resin plate and can realize a scratch-resistant resin plate that is excellent in transparency, surface hardness, impact resistance, and color unevenness, and the same. It is to provide a scratch-resistant resin plate, a protective plate for display and a protective plate for touch panel.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the present invention relates to the following inventions.
(1) A resin plate used as the resin substrate in a scratch-resistant resin plate in which a cured film is formed on at least one surface of the resin substrate, wherein the resin plate is a layer (A ) And a layer (B) made of a resin composition and laminated on at least one surface of the layer (A), the resin composition comprising an alkyl methacrylate-styrene copolymer and styrene A butadiene-based copolymer, and the content of the styrene-butadiene-based copolymer is 1 based on a total of 100% by weight of the alkyl methacrylate-styrene-based copolymer and the styrene-butadiene-based copolymer. A resin plate, which is ˜20% by weight.
(2) The resin plate according to (1), wherein the layer (B) is laminated on both surfaces of the layer (A).
(3) A scratch-resistant resin plate formed by forming a cured film on at least one surface of the resin plate according to (1) or (2).
(4) A protective plate for a display comprising the scratch-resistant resin plate according to (3).
(5) A touch panel protective plate comprising the scratch-resistant resin plate according to (3).

  According to the resin plate of the present invention, there is an effect that a scratch-resistant resin plate excellent in all of transparency, surface hardness, impact resistance and color unevenness resistance can be obtained. Therefore, when a scratch-resistant resin plate using this resin plate is used as a protective plate for a display or a touch panel, these surfaces can be effectively protected even in various environments.

  The resin plate of the present invention has a layer (A) made of a polycarbonate-based resin and a layer (B) laminated on at least one surface of the layer (A) and made of a specific resin composition. .

  Examples of the polycarbonate resin constituting the layer (A) include those obtained by reacting a dihydric phenol and a carbonylating agent by an interfacial polycondensation method, a melt transesterification method, or the like. Examples thereof include those obtained by polymerizing by a method and the like, and 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 {( -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 -3-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, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenyl ketone, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl ester, and the like, and two or more of them are used as necessary. You can also

  Among them, 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) It is preferable to use a dihydric phenol selected from the group consisting of −3,3,5-trimethylcyclohexane and α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene alone or in combination of two or more. Bisphenol A alone or bisphenol A and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl 1 selected from the group consisting of chlorohexane, bisphenol A, 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane and α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene A combined use with two or more dihydric phenols is preferred.

  Examples of the carbonylating agent include carbonyl halides such as phosgene, carbonate esters such as diphenyl carbonate, haloformates such as dihaloformates of dihydric phenols, and two or more of them can be used as necessary.

  On the other hand, the layer (B) is composed of a resin composition containing an alkyl methacrylate-styrene copolymer and a styrene-butadiene copolymer. Among these copolymers, the alkyl methacrylate-styrene copolymer contributes to transparency, surface hardness, and color unevenness among the performances required for the scratch-resistant resin plate.

  The alkyl methacrylate-styrene copolymer is not particularly limited. For example, alkyl methacrylate and styrene are mixed at a desired ratio in a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, and the like. Examples thereof include those obtained by polymerization.

  Examples of the alkyl group of the alkyl methacrylate constituting the copolymer include linear or branched alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl, and hexyl groups. However, it is not limited to this. Substituted styrenes can also be used as styrene. Examples of the substituted styrenes include halogenated styrenes such as chlorostyrene and bromostyrene, and alkylstyrenes such as vinyltoluene and α-methylstyrene. Etc., and two or more of them can be used as necessary.

  In addition to alkyl methacrylate and styrene, other monomers that can be copolymerized with these may be copolymerized in the alkyl methacrylate-styrene copolymer. Examples of other monomers include other than methyl methacrylate such as ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate. Methacrylic acid esters; acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate; Examples include unsaturated acids such as acid and acrylic acid; acrylonitrile, methacrylonitrile, maleic anhydride, phenylmaleimide, cyclohexylmaleimide, etc. It can also be.

  The styrene-butadiene copolymer is not particularly limited. For example, styrene and butadiene are polymerized at a desired ratio by a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, or the like. Can be obtained. Moreover, substituted styrenes can also be used as the styrene constituting this copolymer, and the substituted styrenes include the same substituted styrenes as exemplified in the above-mentioned alkyl methacrylate-styrene copolymer. Can be mentioned. In addition to styrene and butadiene, the copolymer may be copolymerized with other monomers that can be copolymerized therewith. Examples of the other monomers include the above-mentioned alkyl methacrylate- Examples thereof include the same other monomers as exemplified for the styrene copolymer.

  Here, the resin composition containing the above-mentioned alkyl methacrylate-styrene copolymer and styrene-butadiene copolymer is a total of 100 of alkyl methacrylate-styrene copolymer and styrene-butadiene copolymer. The styrene-butadiene copolymer is contained in an amount of 1 to 20% by weight, preferably 1 to 15% by weight, more preferably 1 to 10% by weight, based on weight%. Thereby, the impact resistance of the scratch-resistant resin plate can be improved.

  That is, a cured film is formed on at least one surface of the resin plate to form a scratch-resistant resin plate. When this scratch-resistant resin plate is used as a protective plate for a display or a touch panel, the scratch-resistant resin plate is usually The layer (B) is placed so as to face the front side (viewer side) and the layer (A) faces the back side (display side / touch panel side). In the scratch-resistant resin plate used in such an arrangement, when the resin composition constituting the layer (B) contains a styrene-butadiene copolymer in a specific ratio, the impact resistance of the layer (B). As a result, the impact resistance of the scratch-resistant resin plate becomes excellent. On the other hand, when the content of the styrene-butadiene copolymer is too small, it is difficult to improve the impact resistance, and when it is too large, the surface hardness tends to decrease and the transparency tends to decrease.

  Commercially available alkyl methacrylate-styrene copolymers and styrene-butadiene copolymers can be used. The content of the styrene-butadiene copolymer in the resin composition containing these copolymers is, for example, a commercially available alkyl methacrylate-styrene containing a styrene-butadiene copolymer at a predetermined ratio. It can be adjusted by adding a commercially available alkyl methacrylate-styrene copolymer at a predetermined ratio to the copolymer.

  As a commercially available alkyl methacrylate-styrene copolymer containing a styrene-butadiene copolymer in a predetermined ratio, for example, “Clarastic ST-600” manufactured by Nippon A & L Co., Ltd. can be mentioned. Examples of commercially available alkyl methacrylate-styrene copolymers include “Denka TX polymer TX-100S” and “Denka Acryster KT-75” manufactured by Denki Kagaku Kogyo Co., Ltd.

  It should be noted that the layers (A) and (B) may be applied to the layers (A) and (B) as necessary, for example, a light diffusing agent, matting agent, dye, light stabilizer, ultraviolet absorber, antioxidant, mold release agent, flame retardant, charging One or more additives such as an inhibitor may be added.

  The resin plate has a three-layer structure in which the layer (B) is laminated on both sides of the layer (A) in addition to the two-layer structure in which the layer (B) is laminated only on one side of the layer (A). It may be. From the viewpoint of environmental resistance of the resin plate, a resin plate having a three-layer structure in which the layer (B) is laminated on both sides of the layer (A) is preferable. In the case of a three-layer structure, the composition and thickness of the layers (B) on both sides may be the same or different from each other.

  The resin plate is suitably manufactured by laminating and integrating the layer (A) and the layer (B) by coextrusion molding. In this coextrusion molding, the material of the layer (A) and the material of the layer (B) are respectively melt-kneaded using two or three uniaxial or biaxial extruders, and then fed block die or multi-manifold The molten laminated resin body that is laminated and integrated may be cooled and solidified using, for example, a roll unit. A resin plate produced by coextrusion molding is preferable in that it is easier to perform secondary molding than a resin plate produced by bonding using an adhesive or an adhesive.

  The resin plate is usually in the form of a sheet or film, and the thickness is usually 0.3 to 3 mm, preferably 0.3 to 2 mm, and more preferably 0.4 to 1.6 mm. In the resin plate, the thickness of the layer (B) is usually 30 to 200 μm, preferably 40 to 150 μm, more preferably 50 to 100 μm.

  On the other hand, the resin plate is used as the resin substrate in the scratch-resistant resin plate in which a cured film is formed on at least one surface of the resin substrate. That is, the scratch-resistant resin plate is formed by forming a cured film on at least one surface of the resin plate. When using a scratch-resistant resin plate as a protective plate for a display or touch panel, it is preferable to form a cured film on the surface opposite to the surface facing the display or touch panel, in addition to the opposite surface, It is preferable to form a cured coating also on the surface facing the display or touch panel side. In addition, a cured film can also be formed only on the surface facing the display or touch panel side.

Examples of the layer structure of the scratch-resistant resin plate include the following (i) to (v).
(I) layer (B) / layer (A) / cured coating (ii) cured coating / layer (B) / layer (A) / cured coating (iii) cured coating / layer (B) / layer (A)
(Iv) Cured coating / layer (B) / layer (A) / layer (B)
(V) Cured coating / layer (B) / layer (A) / layer (B) / cured coating When the cured coating is formed on both sides of the resin plate, the composition and thickness of the cured coating on both sides are They may be the same or different.

  The cured film is formed by curing a curable coating composition. The curable coating composition contains a curable compound that provides scratch resistance as an essential component, and, if necessary, for example, a curing catalyst, conductive particles, a solvent, a leveling agent, a stabilizer, an antioxidant, a colorant, and the like. It contains.

  Examples of the curable compound include acrylate compounds, urethane acrylate compounds, epoxy acrylate compounds, carboxyl group-modified epoxy acrylate compounds, polyester acrylate compounds, copolymer acrylate compounds, alicyclic epoxy resins, glycidyl ether epoxy resins, vinyl ether compounds, Examples include oxetane compounds. Among these, from the viewpoint of scratch resistance of the cured film, radical polymerization curable compounds such as polyfunctional acrylate compounds, polyfunctional urethane acrylate compounds, and polyfunctional epoxy acrylate compounds, and thermal polymerization systems such as alkoxysilanes and alkylalkoxysilanes. These curable compounds are preferably used. These curable compounds are preferably cured by irradiating energy beams such as electron beam, radiation, and ultraviolet rays, or cured by heating. These curable compounds may be used alone or in combination of a plurality of compounds.

  Particularly preferred curable compounds are those having at least three (meth) acryloyloxy groups in the molecule. Here, the (meth) acryloyloxy group means an acryloyloxy group or a methacryloyloxy group. In addition, in this specification, “(meth)” when referred to as (meth) acrylate, (meth) acrylic acid, etc. Is the meaning.

  Examples of the compound having at least three (meth) acryloyloxy groups in the molecule include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, glycerin tri (meth) acrylate, pentaglycerol tri ( (Meth) acrylate, pentaerythritol tri- or tetra- (meth) acrylate, dipentaerythritol tri-, tetra-, penta- or hexa- (meth) acrylate, tripentaerythritol tetra-, penta-, hexa- or hepta- ( A poly (meth) acrylate of a polyhydric alcohol having a valence of 3 or more, such as (meth) acrylate; a compound having at least two isocyanato groups in the molecule, and a (meth) acrylate having a hydroxyl group with respect to the isocyanato group Urethane (meth) acrylate obtained by reacting at a ratio of hydroxyl groups equal to or higher than moles, and having 3 or more (meth) acryloyloxy groups in the molecule [for example, diisocyanate and pentaerythritol tri (meth) acrylate The hexafunctional urethane (meth) acrylate is obtained by this reaction]; tris (2-hydroxyethyl) isocyanuric acid tri (meth) acrylate and the like. In addition, although the monomer was illustrated here, you may use these monomers as it is, for example, you may use what was in the form of oligomers, such as a dimer and a trimer. Moreover, you may use a monomer and an oligomer together. These (meth) acrylate compounds may be used alone or in combination of two or more.

  Commercially available compounds can be used as the compound having at least three (meth) acryloyloxy groups in the molecule, and specific examples include, for example, “NK Hard” manufactured by Shin-Nakamura Chemical Co., Ltd. “M101” (urethane acrylate), “NK ester A-TMM-3L” (pentaerythritol triacrylate), “NK ester A-TMMT” (pentaerythritol tetraacrylate), “NK ester A-9530” (dipentaerythritol penta) Acrylate) and “NK ester A-DPH” (dipentaerythritol hexaacrylate), “KAYARAD DPCA” (dipentaerythritol hexaacrylate) manufactured by Nippon Kayaku Co., Ltd., “Nopcocure 200” series manufactured by San Nopco, Dai Nippon Inn Chemical Industry Co., Ltd. of the (stock) "Uni-Dick" series, and the like.

  When a compound having at least three (meth) acryloyloxy groups in the molecule is used as the curable compound, other curable compounds such as ethylene glycol di (meth) acrylate, diethylene glycol di-dioxide are used as necessary. A compound having two (meth) acryloyloxy groups in the molecule, such as (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate may be used in combination. However, the amount used is usually up to 20 parts by weight per 100 parts by weight of the compound having at least three (meth) acryloyloxy groups in the molecule.

  When the curable coating composition is cured with ultraviolet rays, a photopolymerization initiator is preferably used as a curing catalyst. Examples of the photopolymerization initiator include benzyl, benzophenone and derivatives thereof, thioxanthones, benzyldimethyl ketals, α-hydroxyalkylphenones, hydroxyketones, aminoalkylphenones, acylphosphine oxides, and the like. Depending on the situation, two or more of them can be used. The usage-amount of a photoinitiator is 0.1-5 weight part normally with respect to 100 weight part of sclerosing | hardenable compounds.

  As the photopolymerization initiator, a commercially available product can be used. Specific examples thereof include, for example, “IRGACURE 651”, “IRGACURE 184”, “IRGACURE 500”, and “IRGACURE 500” manufactured by Ciba Specialty Chemicals Co., Ltd. IRGACURE 1000 ”,“ IRGACURE 2959 ”,“ DAROCUR 1173 ”,“ IRGACURE 907 ”,“ IRGACURE 369 ”,“ IRGACURE 1700 ”,“ IRGACURE 1800 ”,“ IRGACURE 819 ”,“ IRGACURE IRGA ” Series and DAROCUR (Darocur) series, both “KAYACURE ITX”, “KAYACURE DETX-S”, “KA” manufactured by Nippon Kayaku Co., Ltd. KAYACURE series such as “YACURE BP-100”, “KAYACUREBMS”, “KAYACURE 2-EAQ”, and the like.

  By containing conductive particles in the curable coating composition, antistatic properties can be imparted to the cured coating. Examples of the conductive particles include antimony-tin composite oxide, tin oxide containing phosphorus, antimony oxide such as antimony pentoxide, antimony-zinc composite oxide, titanium oxide, and indium-tin composite oxide (ITO). Such inorganic particles are preferably used. The conductive particles may be used in the form of a sol having a solid content concentration of about 10 to 30% by weight.

  The particle diameter of the conductive particles is usually 0.5 μm or less, and is preferably 0.001 μm or more in terms of the average particle diameter from the viewpoint of antistatic property and transparency of the cured film, and preferably It is 0.1 μm or less, more preferably 0.05 μm or less. The smaller the average particle diameter of the conductive particles, the lower the haze of the scratch-resistant resin plate, and the higher the transparency.

  The usage-amount of the said electroconductive particle is 2-50 weight part normally with respect to 100 weight part of curable compounds, Preferably it is 3-20 weight part. As the amount of the conductive particles used increases, the antistatic property of the cured coating tends to improve. However, when the amount of the conductive particles used excessively decreases the transparency of the cured coating, it is not preferable.

  The conductive particles can be produced by, for example, a gas phase decomposition method, a plasma evaporation method, an alkoxide decomposition method, a coprecipitation method, a hydrothermal method, or the like. The surface of the conductive particles may be surface-treated with, for example, a nonionic surfactant, a cationic surfactant, an anionic surfactant, a silicon coupling agent, an aluminum coupling agent, or the like.

  The curable coating composition may contain a solvent for the purpose of adjusting the viscosity thereof. In particular, when conductive particles are contained, the solvent is preferably contained for dispersion. When preparing a curable coating composition containing conductive particles and a solvent, for example, the conductive particles and the solvent are mixed, the conductive particles are dispersed in the solvent, and then the dispersion is mixed with the curable compound. Alternatively, after mixing the curable compound and the solvent, the conductive particles may be dispersed in the mixed solution.

  The solvent should be one that can dissolve the curable compound and can easily volatilize after coating, and can disperse it when conductive particles are used as a paint component. It is good to be. Examples of such a solvent include alcohols such as diacetone alcohol, methanol, ethanol, isopropyl alcohol, isobutyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 1-methoxy-2-propanol, Examples thereof include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diacetone alcohol, aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, and water. What is necessary is just to adjust the usage-amount of a solvent suitably according to the property etc. of a curable compound.

  When a leveling agent is contained in the curable coating composition, silicone oil is preferably used. Examples thereof include dimethyl silicone oil, phenylmethyl silicone oil, alkyl / aralkyl-modified silicone oil, fluorosilicone oil, and polyether. Modified silicone oil, fatty acid ester modified silicone oil, methyl hydrogen silicone oil, silanol group containing silicone oil, alkoxy group containing silicone oil, phenol group containing silicone oil, methacrylic modified silicone oil, amino modified silicone oil, carboxylic acid modified silicone oil, carb Nord modified silicone oil, epoxy modified silicone oil, mercapto modified silicone oil, fluorine modified silicone oil, polyether modified Recone oil, and the like. These leveling agents may be used alone or in combination of two or more. The amount of the leveling agent used is usually 0.01 to 5 parts by weight with respect to 100 parts by weight of the curable compound.

  As the leveling agent, a commercially available product can be used, and specific examples include, for example, “SH200-100cs”, “SH28PA”, “SH29PA”, “SH30PA” manufactured by Toray Dow Corning Silicone Co., Ltd. , “ST83PA”, “ST80PA”, “ST97PA” and “ST86PA”, all of which are “BYK-302”, “BYK-307”, “BYK-320” and “BYK-” manufactured by Big Chemie Japan Co., Ltd. 330 "and the like.

  The curable coating composition thus obtained is applied to at least one surface of the resin plate to form a curable coating film, and then cured to form a cured coating film, whereby an abrasion-resistant resin plate is obtained. The curable coating may be applied by a coating method such as a bar coating method, a micro gravure coating method, a roll coating method, a flow coating method, a dip coating method, a spin coating method, a die coating method, or a spray coating method. The curable coating film may be cured by irradiation with energy rays, heating, or the like depending on the type of the curable coating composition.

  Examples of energy rays in the case of curing by irradiation with energy rays include ultraviolet rays, electron beams, and radiation, and conditions such as intensity and irradiation time are appropriately selected according to the type of curable coating composition. . Further, in the case of curing by heating, conditions such as temperature and time are appropriately selected according to the type of the curable coating composition, but the heating temperature is generally set so that the resin substrate does not deform. Is preferably 100 ° C. or lower. When the curable coating composition contains a solvent, after application, the solvent may be volatilized and then the curable coating film may be cured, or the solvent may be volatilized and the curable coating film may be cured simultaneously. Also good.

  The thickness of the cured film is preferably 0.5 to 50 μm, more preferably 1 to 20 μm. As the thickness of the cured film is smaller, cracks tend not to occur easily. However, if the thickness is too small, the scratch resistance becomes insufficient, which is not preferable.

  The obtained scratch-resistant resin plate may be subjected to antireflection treatment on its surface by a coating method, a sputtering method, a vacuum deposition method, or the like, if necessary. Alternatively, an antireflection sheet prepared separately may be bonded to one or both sides of the scratch-resistant resin plate to impart an antireflection effect.

  The scratch-resistant resin plate thus obtained is excellent in transparency, surface hardness, impact resistance, and color unevenness, and thus can be used for various applications, but is particularly preferably used as a display protective plate and a touch panel protective plate. .

  Examples of the type of display to be protected include a CRT display, a liquid crystal display, a plasma display, and an EL display. In addition, display applications to be protected include, for example, a display window of a portable information terminal such as a TV or computer monitor, a mobile phone, a personal handy-phone system (PHS), or a PDA (Personal Digital Assistant), a digital camera, or a handy device. Finder part of a portable video camera, a display window of a portable game machine, and the like.

  Examples of the use of the touch panel to be protected include a car navigation system, a portable information terminal, a bank ATM, an operation panel of an industrial machine, a personal computer screen, a touch panel of a portable game machine, and the like.

  In order to produce a display protective plate and a touch panel protective plate from the scratch-resistant resin plate of the present invention, first, if necessary, the scratch-resistant resin plate is subjected to processing such as printing, drilling, and cutting to a required size. do it. Then, if it sets to a display or a touch panel, a display and a touch panel can be protected effectively. In that case, when the cured film is formed in one side of a laminated board, it is good to install so that the surface in which the cured film is formed may become the front side (viewer side). Moreover, when the hardened film is formed in the both surfaces of the laminated board by which a layer (B) is laminated | stacked on one side of a layer (A), a layer (B) is a front side (viewer side) and It is good to install so that it becomes.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these Examples. In the following examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified.

In Examples and Comparative Examples, the following four types of resins were used for the production of resin plates.
Resin 1: Aromatic polycarbonate resin “Caliver 301-10” manufactured by Sumitomo Dow Co., Ltd. was used.
Resin 2: Methyl methacrylate-styrene copolymer resin “Clarastic ST-600” manufactured by Nippon A & L Co., Ltd. was used.
Resin 3: Methyl methacrylate-styrene copolymer resin “Denka TX Polymer TX-100S” manufactured by Denki Kagaku Kogyo Co., Ltd. was used.
Resin 4: Methyl methacrylate-styrene copolymer resin “DENKA ACRYSTER KT-75” manufactured by Denki Kagaku Kogyo Co., Ltd. was used.

  Among the above-described resins 1 to 4, resin 2 contains a styrene-butadiene copolymer in a proportion of 21% based on a total of 100% of methyl methacrylate-styrene copolymer and styrene-butadiene copolymer. It is. This content is a value calculated as follows.

  First, resin 2 was added to tetrahydrofuran (THF) to separate insoluble matters. This insoluble matter was a styrene-butadiene copolymer as a result of composition analysis by pyrolysis gas chromatography mass spectrometry. Next, after drying the insoluble matter, the weight was applied to the formula: (weight of insoluble matter / weight of resin 2) × 100, and the content of the styrene-butadiene copolymer was calculated.

In the examples and comparative examples, the curable coating materials used for the production of the scratch-resistant resin plate are as follows.
Curing paint: 25 parts of dipentaerythritol hexaacrylate [“NK Ester A-DPH” manufactured by Shin-Nakamura Chemical Co., Ltd.], photopolymerization initiator [“IRGACURE 184 manufactured by Ciba Specialty Chemicals Co., Ltd.” 2 parts of antimony pentoxide fine particle sol [“ELCOM V-4514” manufactured by Catalytic Chemical Industry Co., Ltd .; solid content concentration 20%, average particle size less than 0.1 μm] 10 parts 1-methoxy-2-propanol A curable coating prepared by mixing 24 parts, 24 parts isobutyl alcohol, and 15 parts diacetone alcohol was used.

[Examples 1 and 2 and Comparative Examples 1 and 2]
[Production of resin plate]
First, as the material for forming the layer (B), the above-described resins 2 to 4 were mixed in the combinations and proportions shown in Table 1 to obtain a resin composition. Next, the resin 1 which is the material for forming the layer (A) is a single screw extruder manufactured by Toshiba Machine Co., Ltd. having a diameter of 65 mmφ, and the resin composition which is the material for forming the layer (B) is Hitachi Zosen Corporation having a diameter of 45 mmφ. Each was melted with a single screw extruder.

  Subsequently, these were laminated and extruded through a multi-manifold die having a set temperature of 260 ° C. Then, the obtained film-like material is sandwiched between a pair of metal rolls having smooth surfaces and molded and cooled, and layers each having a thickness of 70 μm are formed on both sides of the layer (A) having a thickness of 360 μm. A resin plate having a total thickness of 500 μm obtained by laminating (B) was obtained.

[Production of scratch-resistant resin plate]
First, the obtained resin plate was cut into a size of 100 mm × 80 mm, and a coating film of a curable paint was formed on both surfaces of the resin plate by a dipping method. Next, after drying at room temperature for 1 minute and further drying in a hot air oven at 50 ° C. for 3 minutes to volatilize the solvent, this coating film was subjected to 0.5 J / cm ² using a 120 W high-pressure mercury lamp. The resin film was cured by irradiating with ultraviolet rays to obtain a scratch-resistant resin plate having a cured film having a thickness of 3.5 μm on each side of the resin plate.

[Evaluation]
The obtained resin plate and scratch-resistant resin plate were evaluated for total light transmittance, haze, pencil hardness, falling ball strength, and color unevenness resistance. Each evaluation method is shown below, and the results are shown in Table 1.

<Total light transmittance>
The total light transmittance (Tt) of the resin plate was measured according to JIS K7361-1.

<Haze>
According to JIS K7136, the haze (Haze) of the resin plate was measured.

<Pencil hardness>
The pencil hardness of the resin plate was measured according to JIS K5600.

<Falling ball strength>
The falling ball strength of the resin plate was evaluated as follows. First, the resin plate was cut into a size of 85 mm × 65 mm to obtain a test piece. Next, a metal mold having an outer dimension of 85 mm × 65 mm, an inner dimension of 47 mm × 35 mm, and a thickness of 1 mm is placed on the falling surface side, and an outer dimension of 85 mm × 65 mm, an inner dimension of 47 mm × 35 mm, and a thickness of 2 mm. Is disposed on the side of the falling spherical surface, the test piece is sandwiched between these metal molds, an acrylic plate having a thickness of 85 mm × 65 mm and a thickness of 1 mm is disposed below, and a metal plate having a thickness of 85 mm × 65 mm is further disposed below. The test piece was fixed so that the falling surface side faced upward.

  Then, a metal ball having a weight of 36 g and a diameter of 20 mmφ was dropped from a height of 50 cm to the center of the test piece. At this time, the case where the test piece was not broken was evaluated as ◯, and the case where the test piece was broken was evaluated as x.

<Color unevenness resistance>
The presence or absence of color unevenness in the scratch-resistant resin plate was visually observed. At this time, the case where color unevenness was not conspicuous was evaluated as ◯, and the case where color unevenness was conspicuous was evaluated as x.

  As is clear from Table 1, Examples 1 and 2 are all in terms of transparency (total light transmittance / cloudiness), surface hardness (pencil hardness), impact resistance (falling ball strength), and color unevenness resistance. You can see that it is excellent. On the other hand, the comparative example 1 which does not contain a styrene-butadiene copolymer showed a result inferior in impact resistance (falling ball strength). Further, Comparative Example 2 in which the content of the styrene-butadiene copolymer is more than 20% by weight is inferior in surface hardness (pencil hardness), and the transparency (total light transmittance / haze) is also in Example 1. The result was inferior to 2.

Claims (5)

A resin plate used as the resin substrate in a scratch-resistant resin plate in which a cured film is formed on at least one surface of the resin substrate,
The resin plate is
A layer (A) made of polycarbonate resin;
A layer (B) laminated on at least one surface of the layer (A) and made of a resin composition;
The resin composition is
Containing an alkyl methacrylate-styrene copolymer and a styrene-butadiene copolymer,
The content of the styrene-butadiene copolymer is 1 to 20% by weight based on a total of 100% by weight of the alkyl methacrylate-styrene copolymer and the styrene-butadiene copolymer. Resin plate.   The resin plate according to claim 1, wherein the layer (B) is laminated on both surfaces of the layer (A).   A scratch-resistant resin plate obtained by forming a cured film on at least one surface of the resin plate according to claim 1.   A protective plate for a display comprising the scratch-resistant resin plate according to claim 3.   A protective plate for a touch panel comprising the scratch-resistant resin plate according to claim 3.