JP5186983B2 - Scratch-resistant resin plate and its use - Google Patents

Description

  The present invention relates to a scratch-resistant resin plate and its use.

  In recent years, portable telephones such as cellular phones and PHS (Personal Handy-phone System) have become popular with the Internet, and in addition to simple voice transmission functions, portable information terminals have a function to display text information and image information. Has been widely spread as. In addition to such portable telephones, PDAs (Personal Digital Assistants) that have functions such as an address book as well as Internet functions and e-mail functions are also widely used. In this specification, such mobile phones, PHS, PDAs, and the like are collectively referred to as “portable information terminals”. That is, the “portable information terminal” in the present specification is a generic term for a device that has a window that can be carried by a person and that displays character information, image information, and the like.

  These portable information terminals display character information and image information by a method such as liquid crystal or EL (electroluminescence). The display window is made of a transparent resin as a protective plate. In general, methacrylic resin plates are preferably used from the viewpoint of transparency (see, for example, Patent Documents 1 to 3). In order to prevent the surface from being scratched, it has been proposed to provide a scratch-resistant (hard coat) cured film with a curable paint (see the patent document).

Japanese Patent Laid-Open No. 2002-6676 JP 2004-143365 A JP 2004-299199 A

  Conventionally proposed display window protection plates for portable information terminals do not necessarily have sufficient environmental resistance. For example, when they are exposed to high temperatures and high humidity for a long time, they are prone to warp or cracks in the cured coating. There is a problem that it is easy to occur.

  Therefore, as a result of intensive studies to develop a scratch-resistant resin plate suitable as a display window protection plate for a portable information terminal having excellent environmental resistance, the present inventor has found that the polycarbonate resin layer has at least one surface. It has been found that a desired scratch-resistant resin plate can be obtained by forming a cured film on at least one of the acrylic resin layers using a laminated plate formed by laminating a specific acrylic resin layer as a substrate. It came to be completed.

That is, in the present invention, a cured coating is formed on at least one layer (B) of a substrate in which an acrylic resin layer (B) is laminated on at least one surface of a polycarbonate resin layer (A). The acrylic resin comprises 60 to 95% by weight of methyl methacrylate units, methacrylic acid units, acrylic acid units, maleic anhydride units, N-substituted or unsubstituted maleimide units, glutaric anhydride structural units, and The present invention provides a scratch-resistant resin plate having 5 to 40% by weight of units selected from glutarimide structural units and having a glass transition temperature of 110 ° C. or higher.

  According to the present invention, there is also provided a display window protection plate for a portable information terminal made of this scratch-resistant resin plate. Furthermore, not only the portable information terminal but also other portable display devices and installation type There is also provided a display protection plate intended for display devices.

  The scratch-resistant resin plate of the present invention is excellent in environmental resistance. By using this scratch-resistant resin plate as a display protective plate, particularly as a display window protective plate for a portable information terminal, the display window is effective. Can be protected.

  Hereinafter, the present invention will be described in detail. The scratch-resistant resin plate of the present invention is a laminate in which a layer (B) made of a predetermined acrylic resin is laminated on at least one surface of a layer (A) made of polycarbonate resin, and at least one of the layers. (B) A cured film is formed on the surface.

  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, etc. Examples thereof include those obtained by polymerizing by an exchange method 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 {(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 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, etc., and if necessary, use two or more of them 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) ) -3,3,5-trimethylcyclohexane and α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene are preferably used alone or in combination of two or more. In particular, bisphenol A Of 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane and bisphenol A, Use in combination with one or more dihydric phenols selected from 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane and α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene preferable.

  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.

As the acrylic resin constituting the layer (B), based on all monomer units, methyl methacrylate units 60 to 95% by weight, methacrylic acid units, acrylic acid units, maleic anhydride units, N-substituted or A polymer having 5 to 40% by weight of units selected from unsubstituted maleimide units, glutaric anhydride structural units, and glutarimide structural units and having a glass transition temperature of 110 ° C. or higher is used.

Here, the methyl methacrylate unit is a unit [—CH ₂ —C (CH ₃ ) (CO ₂ CH ₃ ) —] formed by polymerization of methyl methacrylate, and the methacrylic acid unit is obtained by polymerization of methacrylic acid. Unit [—CH ₂ —C (CH ₃ ) (CO ₂ H) —] formed, and the acrylic acid unit is a unit [—CH ₂ —CH (CO ₂ H) — formed by polymerization of acrylic acid. ]. The maleic anhydride unit is a unit [formula (1)] formed by polymerization of maleic anhydride, and the N-substituted or unsubstituted maleimide unit is formed by polymerization of N-substituted or unsubstituted maleimide. Unit [formula (2)].

In the formula (2), R ¹ represents a hydrogen atom or a substituent. Examples of the substituent include an alkyl group such as a methyl group and an ethyl group, a cycloalkyl group such as a cyclohexyl group, and a phenyl group. Aralkyl groups such as an aryl group and a benzyl group can be mentioned, and the carbon number is usually about 1 to 20.

  The glutaric anhydride structural unit is a unit having a glutaric anhydride structure, and the glutarimide structural unit is a unit having a glutarimide structure. Typically, each of the following formulas (3) and ( 4).

In formula (3), R ² represents a hydrogen atom or a methyl group, and R ³ represents a hydrogen atom or a methyl group. In the formula (4), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents a hydrogen atom or a substituent, and examples of the substituent include a methyl group, Examples thereof include an alkyl group such as an ethyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group, and an aralkyl group such as a benzyl group, and the carbon number thereof is usually about 1 to 20.

  A methyl methacrylate unit, a methacrylic acid unit, an acrylic acid unit, a maleic anhydride unit, and an N-substituted or unsubstituted maleimide unit are used as polymerization raw materials, respectively, methyl methacrylate, methacrylic acid, acrylic acid, maleic anhydride. , And N-substituted or unsubstituted maleimides.

  The glutaric anhydride structural unit is a homopolymer of methyl methacrylate, or a copolymer of methyl methacrylate and methacrylic acid and / or acrylic acid, such as sodium hydroxide, potassium hydroxide, sodium methylate. In the presence of a basic compound, it can be introduced usually by heat treatment at 150 to 350 ° C., preferably 220 to 320 ° C. for modification.

  The glutarimide structural unit is a homopolymer of methyl methacrylate, or a copolymer of methyl methacrylate and methacrylic acid and / or acrylic acid, usually in the presence of ammonia or primary amine at 150 to 350 ° C., It can introduce | transduce by heat-processing in the range of 220-320 degreeC preferably, and making it modify | denaturate.

  The monomer unit composition of the acrylic resin is preferably 65 to 95% by weight, more preferably 70 to 92% by weight of methyl methacrylate units, and methacrylic acid units, acrylic acid units, maleic anhydride units, N -The unit chosen from a substituted or unsubstituted maleimide unit, a glutaric anhydride structural unit, and a glutarimide structural unit becomes like this. Preferably it is 5-35 weight%, More preferably, it is 8-30 weight%. The glass transition temperature of the acrylic polymer is preferably 115 ° C. or higher, and usually 150 ° C. or lower.

  In addition, acrylic resin is another unit as required, for example, methacrylic acid ester other than methyl methacrylate such as bornyl methacrylate, fentyl methacrylate, menthyl methacrylate, adamantyl methacrylate, methyl acrylate, butyl acrylate. May have monomer units such as acrylic acid ester such as styrene, aromatic vinyl compound such as α-methylstyrene, vinylcyan compound such as acrylonitrile, etc. Usually up to 20% by weight, based on body units.

  The acrylic resin or its raw material can be produced by a usual method such as suspension polymerization, emulsion polymerization or bulk polymerization. Usually, a chain transfer agent or a radical polymerization initiator is used for the polymerization. As the chain transfer agent, mercaptans such as dodecyl mercaptan and octyl mercaptan are preferably used. As the radical polymerization initiator, an organic peroxide is used. And azo compounds are preferably used.

  The weight average molecular weight of the acrylic resin is usually 20,000 to 500,000, preferably 50,000 to 200,000, from the viewpoint of moldability.

  By adding a rubbery polymer to the acrylic resin, the impact resistance of the resulting substrate can be improved. Examples of rubbery polymers include acrylic multilayered polymers and 5 to 80 parts by weight of rubbery polymer with 20 to 95 parts by weight of ethylenically unsaturated monomers such as acrylic unsaturated monomers. Examples thereof include graft copolymers obtained by graft polymerization. The acrylic multilayer structure polymer should have a rubber elastic layer or an elastomer layer contained therein in an amount of about 20 to 60% by weight, and should preferably have a hard layer at the outermost layer. A structure including a hard layer may be used.

  The rubber elastic layer or the elastomer layer is preferably an acrylic polymer layer having a glass transition point (Tg) of less than 25 ° C., and specifically includes lower alkyl acrylate, lower alkyl methacrylate, and lower alkoxyalkyl acrylate. A polymer obtained by crosslinking one or more monofunctional monomers selected from cyanoethyl acrylate, acrylamide, hydroxy lower alkyl acrylate, hydroxy lower alkyl methacrylate, acrylic acid and methacrylic acid with a polyfunctional monomer such as allyl methacrylate. It should be a coalesced layer.

  The hard layer may be an acrylic polymer layer having a Tg of 25 ° C. or more, and specifically, an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms is polymerized alone or as a main component. It should be a thing. When the copolymer is mainly composed of alkyl methacrylate, the copolymer component may be a monofunctional monomer such as other alkyl methacrylate, alkyl acrylate, styrene, substituted styrene, acrylonitrile, or methacrylonitrile. Further, a polyfunctional monomer may be added to form a crosslinked polymer.

  Acrylic multilayer structure polymers are described, for example, in JP-B-55-27576, JP-A-6-80739, JP-A-49-232922, and the like.

  In a graft copolymer obtained by graft polymerization of 20 to 95 parts by weight of an ethylenically unsaturated monomer to 5 to 80 parts by weight of a rubbery polymer, examples of the rubbery polymer include polybutadiene rubber and acrylonitrile / butadiene. Copolymer rubber, diene rubber such as styrene / butadiene copolymer rubber, acrylic rubber such as polybutyl acrylate, polypropyl acrylate, poly-2-ethylhexyl acrylate, ethylene / propylene / non-conjugated diene rubber, etc. It is done. Examples of the ethylenic monomer used for graft copolymerization with the rubbery polymer include styrene, acrylonitrile, and alkyl (meth) acrylate. These graft copolymers are described, for example, in JP-A Nos. 55-147514 and 47-9740.

  When the rubber-like polymer is dispersed in the acrylic resin, the dispersion ratio is usually 3 to 150 parts by weight, preferably 5 to 50 parts by weight with respect to 100 parts by weight of the acrylic resin. If the amount of the rubbery polymer is too large, the surface hardness is lowered, which is not preferable.

  In addition, for each of the polycarbonate resin and the acrylic resin, for example, a light diffusing agent, a matting agent, a dye, a light stabilizer, an ultraviolet absorber, an antioxidant, a release agent, a flame retardant, and an antistatic agent. You may add 1 type, or 2 or more types of additives, such as.

  The substrate of the scratch-resistant resin plate of the present invention is preferably produced by laminating and integrating a layer (A) made of polycarbonate resin and a layer (B) made of acrylic resin by coextrusion molding. In this co-extrusion molding, the material of the layer (A) and the material of the layer (B) are melted and kneaded using two or three uniaxial or biaxial extruders, respectively, and then fed block or multi-manifold die. The melt-laminated resin body laminated and integrated may be cooled and solidified using, for example, a roll unit. A substrate manufactured by coextrusion molding is preferable in that it can be easily formed into a necessary shape as compared with a substrate manufactured by bonding using an adhesive or an adhesive.

  The surface of the obtained substrate may be smooth or may be provided with fine irregularities. For imparting smoothness and uneven shape, a method of making a plate by bringing at least one surface of the molten resin laminate into contact with a roll or a belt is preferable in that a substrate having good surface properties can be obtained. In particular, from the viewpoint of improving the smoothness of the substrate or the precision of giving the shape, a method in which both sides of the molten resin laminate are brought into contact with the roll surface or the belt surface is preferable. The roll or belt used in this case is preferably made of metal. Therefore, as a preferable form, there is a method of molding the molten resin laminate in a state where it is brought into contact with at least one mirror roll, more preferably in contact with two mirror rolls. Moreover, you may use the thing which has elasticity in either one as a mirror surface roll.

  The substrate may have a two-layer structure in which the layer (B) is laminated on only one side of the layer (A), or three layers in which the layer (B) is laminated on both sides of the layer (A). A structure having a three-layer structure may have a structure having a two-layer structure because the surface impact property may be reduced and cracking may occur depending on the thickness of the layer (B) and the type of acrylic resin. Those are preferred.

  The substrate 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 1.5 mm. And in a board | substrate, the thickness of a layer (B) is 50-120 micrometers normally, Preferably it is 60-110 micrometers or more, More preferably, you may be 70-100 micrometers. Thus, by setting the thickness of the layer (B), the substrate is more difficult to break and sufficient surface hardness can be obtained. In the case of a three-layer structure, the thicknesses of both layers (B) may be the same or different.

  A scratch-resistant cured film is formed on the layer (B) made of acrylic resin on the substrate. Here, the cured coating film may be formed on both surfaces of the substrate, or may be formed only on the single-sided layer (B).

  Therefore, typical examples of the layer structure of the scratch-resistant resin plate include (1): cured film / layer (B) / layer (A), (2): cured film / layer (B) / layer (A ) / Cured film, (3): cured film / layer (B) / layer (A) / layer (B), (4): cured film / layer (B) / layer (A) / layer (B) / cured A film can be mentioned.

  The cured film formed on the layer (B) and the cured film formed on the layer (A) may be the same or different.

  The curable coating used to form the cured film is mainly composed of various curable compounds that provide scratch resistance, and, if necessary, a solvent, conductive inorganic particles, a curing catalyst, and the like are mixed. .

  First, the curable compound will be described. An acrylate compound, a urethane acrylate compound, an epoxy acrylate compound, a carboxyl group-modified epoxy acrylate compound, a polyester acrylate compound, a copolymer acrylate, an alicyclic epoxy resin, a glycidyl ether epoxy resin, a vinyl ether compound, Of the oxetane compounds, one having an effect of imparting scratch resistance may be used. Among them, curable compounds that provide high scratch resistance include polyfunctional acrylate compounds, polyfunctional urethane acrylate compounds, polyfunctional epoxy acrylate compounds, radical polymerization curable compounds, alkoxysilanes, alkylalkoxysilanes, etc. Polymerizable curable compounds can be mentioned. These curable compounds are cured by irradiating energy beams such as an 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.

  Among these curable compounds, preferred are compounds 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 referring to (meth) acrylate, (meth) acrylic acid, and the like has the same meaning.

  Examples of the curable compound having at least three (meth) acryloyloxy groups in the molecule include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, glycerin tri (meth) acrylate, penta Glycerol tri (meth) acrylate, pentaerythritol tri- or tetra- (meth) acrylate, dipentaerythritol tri-, tetra-, penta- or hexa- (meth) acrylate, tripentaerythritol tetra-, penta-, hexa- or Poly (meth) acrylates of trihydric or higher polyhydric alcohols such as hepta (meth) acrylate; a compound having at least two isocyanate groups in the molecule and a (meth) acrylate monomer having a hydroxyl group is added to the isocyanate. Urethane (meth) acrylate obtained by reacting at a ratio of at least equimolar hydroxyl groups with respect to the number of (meth) acryloyloxy groups in one molecule [for example, diisocyanate and pentaerythritol tris The reaction of (meth) acrylate yields a 3-6 functional urethane (meth) acrylate]; and tris (meth) acrylate of tris (2-hydroxyethyl) isocyanuric acid. Although the monomers are exemplified here, these monomers may be used as they are, or for example, those in the form of oligomers such as dimers and trimers may be used. 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.

  Since some curable compounds having at least three (meth) acryloyloxy groups are commercially available, such commercially available products can also be used. Examples of commercially available products include “NK Hard M101” [Shin Nakamura Chemical Co., Ltd., urethane acrylate], “NK Ester A-TMM-3L” [Shin Nakamura Chemical Co., Ltd., Pentaerythritol Tri Acrylate], “NK Ester A-TMMT” (Shin Nakamura Chemical Co., Ltd., pentaerythritol tetraacrylate), “NK Ester A-9530” (Shin Nakamura Chemical Co., Ltd., dipentaerythritol pentaacrylate), “NK Ester A-DPH” [Shin Nakamura Chemical Co., Ltd., dipentaerythritol hexaacrylate], “KAYARAD DPCA” [Nippon Kayaku Co., Ltd., dipentaerythritol hexaacrylate], “Nopcocure 200” series [ San Nopco Co., Ltd.], “Unidic And the like series [Dainippon Ink and Chemicals Co., Ltd. product].

  In addition, the curable coating is a curable compound other than the compound having at least three (meth) acryloyloxy groups in the molecule, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth), if necessary. It may contain a compound having two (meth) acryloyloxy groups in the molecule, such as acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, The amount 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 is cured with ultraviolet rays, a photopolymerization initiator is used. Examples of the photopolymerization initiator include benzyl, benzophenone and derivatives thereof, thioxanthones, benzyl dimethyl ketals, α-hydroxyalkylphenones, hydroxyketones, aminoalkylphenones, and acylphosphine oxides. The addition amount of the photopolymerization initiator is generally in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the curable compound.

  These photopolymerization initiators can be used alone, or many can be used in combination of two or more. Moreover, since these various photoinitiators are marketed, such a commercial item can be used. Examples of the commercially available photopolymerization initiator include “IRGACURE 651”, “IRGACURE 184”, “IRGACURE 500”, “IRGACURE 1000”, “IRGACURE 2959”, “DAROCUR 1173”, “IRGACURE 907”, “IRGACURE 369”. “IRGACURE 1700”, “IRGACURE 1800”, “IRGACURE 819”, “IRGACURE 784” [The above IRGACURE series and DAROCUR series are sold by Ciba Specialty Chemicals Co., Ltd.], “KAYACURE "ITX", "KAYACURE DETX-S", "KAYACURE BP-100", "KAYACUREBMS", "K YACURE 2-EAQ "[more KAYACURE (Kayacure) series, sold by Nippon Kayaku Co., Ltd.] and the like.

  Further, in the present invention, in order to impart antistatic properties to the cured film and prevent adhesion of chips during cutting of the scratch-resistant resin plate to improve workability, conductive particles are added to the curable paint. Can be added. Examples of the conductive particles used for this purpose include inorganic particles such as tin oxide doped with antimony, tin oxide doped with phosphorus, antimony oxide, zinc antimonate, titanium oxide, and ITO (indium tin oxide). Can be mentioned.

  When blending conductive particles, the particle size can be appropriately selected depending on the type of particles, and usually 0.5 μm or less is used, but the resulting cured coating has an antistatic property and transparency. From the viewpoint of properties, the average particle diameter is preferably 0.001 μm or more and 0.1 μm or less, more preferably 0.001 μm or more and 0.05 μm or less. If the average particle diameter of the conductive particles is too large, the haze of the resulting scratch-resistant resin plate increases, and the transparency may decrease. Moreover, the usage-amount of electroconductive particle is about 2-50 weight part normally with respect to 100 weight part of curable compounds, Preferably it is about 3-20 weight part. If the amount is too small, the effect of improving the antistatic property becomes poor. Moreover, when there is too much the quantity, there exists a possibility of reducing the transparency of a cured film.

  Such conductive particles can be produced by, for example, a vapor 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.

  A diluting solvent is used for the curable coating for the purpose of adjusting the viscosity of the coating, and in particular when conductive particles are added, it is necessary for its dispersion. When conductive particles are used and a solvent is used, for example, the conductive particles and the solvent are mixed, and after the conductive particles are dispersed in the solvent, they may be mixed with a curable compound or cured. After mixing the active compound and the solvent, conductive particles may be added thereto and mixed.

  The solvent is not particularly limited as long as it can dissolve the curable compound and can volatilize after coating, and in the case of using conductive particles as a coating component, any solvent can be used. For example, alcohols such as diacetone alcohol, methanol, ethanol, isopropyl alcohol, isobutyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 1-methoxy-2-propanol, acetone, methyl ethyl ketone, methyl isobutyl Examples include ketones, ketones such as diacetone alcohol, aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, and water. There is no particular limitation on the amount of the solvent used in the curable coating, and the solvent can be used in an appropriate amount according to the properties of the curable compound.

  Moreover, you may add a well-known leveling agent to this curable coating material. Examples of the leveling agent include silicone oils. Usable silicone oils include dimethyl silicone oil, phenylmethyl silicone oil, alkyl / aralkyl modified silicone oil, fluorosilicone oil, 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, methacryl-modified silicone oil, amino-modified silicone oil, carboxylic acid-modified silicone oil, carbinol-modified silicone oil, epoxy-modified silicone oil, mercapto-modified Examples thereof include silicone oil, fluorine-modified silicone oil, and polyether-modified silicone oil. Since these leveling agents are commercially available, commercially available products can be used. Examples of commercially available leveling agents include “SH200-100cs”, “SH28PA”, “SH29PA”, “SH30PA”, “ST83PA”, “ST80PA”, “ST97PA”, “ST86PA” [all of which are Toray Dow Corning -Sold by Silicone Co., Ltd.]. These leveling agents may be used alone or in combination of two or more. The amount of the leveling agent used is appropriately selected according to the properties of the curable coating, but is generally about 0.01 to 5 parts by weight with respect to 100 parts by weight of the curable compound.

  Further, the curable coating material may contain additives such as a stabilizer, an antioxidant, and a colorant.

  Thus, the curable coating obtained by mixing the curable compound with conductive particles, a solvent, a leveling agent, a photopolymerization initiator, etc., if necessary, is applied to the surface of the substrate and applied to the curable coating film. Then, by subsequently curing, it is possible to obtain a scratch-resistant resin plate having a scratch-resistant cured film formed on the surface.

  When a curable coating is applied to a substrate to form a curable coating film, for example, 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, a spray What is necessary is just to apply | coat by well-known coating methods, such as a coating method. Thus, a curable coating film is formed on the surface of the substrate. Thereafter, the curable coating film is cured by irradiating or heating energy rays such as ultraviolet rays and electron beams according to the type of the curable coating, thereby forming a scratch-resistant cured coating.

  Examples of energy rays in the case of curing by irradiating energy rays include ultraviolet rays, electron beams, and radiation, and the intensity and irradiation time are appropriately selected according to the type of curable paint to be used. In addition, the heating temperature and the heating time for curing by heating are appropriately selected according to the type of curable paint to be used, but in the case of heat curing, generally, the substrate is not deformed. Is preferably 100 ° C. or lower. When the curable paint 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 cured simultaneously. Also good.

The cured film formed on the layer (A) has a cured film refractive index n and a refractive index (ns) of the layer (A) of the following formula: | n−ns | ≦ 0.01
It is preferable that If this difference in refractive index is greater than 0.01, a rainbow pattern is likely to occur due to light interference between the cured coating and the layer (A), which is not preferable in appearance.

  In order to adjust the refractive index of the cured film within the range of the above formula, a compound having a (meth) acryloyloxy group having an aromatic ring or a halogen atom in the molecule is used as a part of the curable compound, or High refractive index organic or inorganic particles can be dispersed in the cured coating, or a combination of the two can be used. Among them, a method of dispersing high refractive index inorganic particles can be preferably used because the refractive index can be easily adjusted.

  Examples of the high refractive index inorganic particles include titanium oxide, tin oxide, antimony oxide, indium oxide, zirconium oxide, metal oxide particles such as zinc oxide, antimony-zinc composite oxide, antimony-tin composite oxide, and indium. -Composite metal oxide particles such as tin composite metal oxide, composite oxide particles such as phosphorus-doped tin oxide, and the like. Among them, conductive particles such as antimony oxide, antimony-zinc composite oxide, antimony-tin composite oxide, indium-tin composite metal oxide, and phosphorus-doped tin oxide have not only the adjustment of refractive index but also antistatic properties at the same time. Since it can provide, it is more preferable.

  The addition amount of the high refractive index particles is appropriately determined according to the refractive index and the strength of the film. The particle diameter of the high refractive index particles is usually 0.001 to 0.3 μm, preferably 0.01 to 0.1 μm, and more preferably 0.001 to 0.05 μm in terms of average particle diameter. If the average particle size of the high refractive index particles is too large, the haze of the resulting scratch-resistant resin plate increases and transparency may be lowered.

  The thickness of the cured film is preferably about 0.5 to 50 μm, more preferably about 1 to 20 μm. If the thickness of the cured coating is too large, cracks are likely to occur, and if it is too small, the scratch resistance tends to be insufficient.

  The obtained scratch-resistant resin plate can be subjected to antireflection treatment on its surface by a known method such as a coating method, a sputtering method, or a vacuum deposition method. It is also possible to provide an antireflection effect by bonding an antireflection sheet prepared separately to one or both sides of the scratch-resistant resin plate.

  The scratch-resistant resin plate thus obtained is excellent in environmental resistance and can be used in various applications. Among them, it is suitable as a display window protection plate for portable information terminals such as mobile phones. And other portable display devices such as finder parts for handheld video cameras, display window protection plates for portable game consoles, and screen protection plates for home and commercial televisions. It can also be used as a protective plate for a display that also targets installation type display devices. In particular, the scratch-resistant resin plate of the present invention has an advantageous effect as a display window protective plate for a mobile phone, particularly a mobile phone having a structure in which a display portion including a display window is folded to cover an operation button portion when not in use. Demonstrate.

  In order to produce a protective plate for a display from the scratch-resistant resin plate of the present invention, first, if necessary, processing such as printing, drilling, etc. may be performed, and cutting processing may be performed to a required size. Then, if it is set on a display, a display with high scratch resistance can be obtained.

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

[Preparation of acrylic resin (a1)]
In an autoclave equipped with a stirrer, 2200 parts of water and 2.4 parts of hydroxycellulose were charged and dissolved, and then 1440 parts of methyl methacrylate, 160 parts of methacrylic acid, 6.4 parts of lauryl mercaptan, and 5.6 parts of lauroyl peroxide. And the mixture was stirred and heated to 80 ° C. for polymerization. After 1 hour and 40 minutes, the temperature was raised to 98 ° C., and polymerization was further carried out for 1 hour to complete the reaction. Thereafter, the polymer was cooled, centrifuged, washed with water and dried at 80 ° C. This operation was repeated several times to obtain dry beads. To this dried bead, 0.03 part of sodium hydroxide was mixed with 100 parts of bead with a Henschel mixer, and a 40 mmφ degassing extruder [manufactured by Tanabe Plastics Machine Co., Ltd., VS-40-28 type, L / D = 28], granulation was performed at a screw rotation speed of 50 rpm and a resin temperature of 280 ° C. to obtain an acrylic resin (a1). The glutaric anhydride structural unit contained in the acrylic resin (a1) was quantified using an absorption at 1805 cm ⁻¹ with an infrared spectrophotometer, and as a result, it was 7.8%. Moreover, this acrylic resin (a1) had a glass transition temperature of 115 ° C. The glass transition temperature is an extrapolated glass transition start temperature obtained at a heating rate of 10 ° C./min by differential scanning calorimetry according to JIS K7121.

[Preparation of acrylic resin (a2)]
A monomer consisting of 93% methyl methacrylate and 7% methyl acrylate, 0.25% of n-dodecyl mercaptan as a chain transfer agent with respect to the monomer and 0.25% of benzoyl peroxide as the radical polymerization initiator with respect to the monomer % Was used for suspension polymerization to obtain an acrylic resin (a2). This acrylic resin (a2) had a glass transition temperature of 96 ° C.

[Preparation of curable paint (b1)]
30 parts of dipentaerythritol hexaacrylate [Shin Nakamura Chemical Co., Ltd. “NK Ester A-DPH”], 35 parts of 1-methoxy-2-propanol, 35 parts of isobutyl alcohol, photopolymerization initiator [Ciba Specialty Chemicals ( Co., Ltd. “IRGACURE 184”] and 2 parts of silicone oil [“SH28PA” of Toray Dow Corning Silicone Co., Ltd.] were mixed to prepare a curable paint (b1).

[Preparation of curable paint (b2)]
28 parts of dipentaerythritol hexaacrylate [“NK Ester A-DPH” from Shin-Nakamura Chemical Co., Ltd.], 1 part of photopolymerization initiator [IRGACURE 184 from Ciba Specialty Chemicals Co., Ltd.] Antimony pentoxide fine particle sol [ ELCOM-7514 of Catalytic Chemical Industry Co., Ltd .; 8 parts of solid content 20%], 32 parts of 1-methoxy-2-propanol, 32 parts of isobutyl alcohol, and silicone oil [Toray Dow Corning Silicone Co., Ltd. “SH28PA”] 0.045 part was mixed to prepare a curable coating (b2).

[Preparation of curable paint (b3)]
13.5 parts of dipentaerythritol hexaacrylate [Shin Nakamura Chemical Co., Ltd. “NK Ester A-DPH”], photopolymerization initiator [IRGACURE 184 of Ciba Specialty Chemicals Co., Ltd.], phosphorus-doped tin oxide [ 16.5 parts of average particle diameter 0.1 μm], 69 parts of 1-methoxy-2-propanol, and 0.02 part of silicone oil [“SH28PA” of Toray Dow Corning Silicone Co., Ltd.] are cured. A paint (b3) was prepared.

Example 1
(1) Production of substrate Polycarbonate resin (Caliber 301-10, manufactured by Sumitomo Dow Co., Ltd., refractive index 1.585) was melt-kneaded using a 40 mmφ single screw extruder, and acrylic resin (a1) was mixed with 20 mmφ single screw extruder. Is melted and kneaded using a feed block, and two layers are formed so that one surface layer becomes an acrylic resin through a feed block, and then extruded through a T-shaped die and cooled so that both surfaces are completely in contact with the polishing roll. Thus, a multilayer substrate having a thickness of 0.5 mm was obtained. At this time, the thickness of the acrylic resin (a1) layer was 70 μm.

(2) Production of Scratch Resistant Resin Plate The substrate obtained in (1) above was cut into a size of 10 cm × 6 cm. A coating of curable paint (b1) was formed on the acrylic resin (a1) layer using a 20 bar coater. Next, after drying at room temperature for 1 minute and further drying in a hot air oven at 45 ° C. for 10 minutes to volatilize the solvent, this coating film was subjected to 0.5 J / cm ² using a 120 W high-pressure mercury lamp. It was cured by irradiating with ultraviolet rays to obtain a scratch-resistant resin plate having a cured coating on one side [on the acrylic resin (a1) layer]. The refractive index of the cured film was 1.52. The scratch-resistant resin plate was evaluated as follows, and the results are shown in Table 1.

〔transparency〕
Total light transmittance (Tt) was measured according to JIS K7361-1, and haze (H) was measured according to JIS K7136.

[Thickness of cured film]
The film thickness was measured using a film thickness measuring apparatus (F-20 manufactured by Filmmetrics).

〔Pencil hardness〕
Measured according to JIS K 5600.

[Surface resistance]
Measured according to ASTM-D257.

[Durability sled test]
Cut out a 7cm x 5cm test piece and left it in an environment of 85 ° C for 3 days. Then, place the test piece on the horizontal surface so that the four corners are lifted up, measure its height, and do the same before the test. The maximum difference from the measured value was taken as the amount of warpage.

[Pressure strength]
A 55 mm x 85 mm test piece is placed on a metal frame with an outer diameter of 60 mm x 100 mm and an inner diameter of 30 mm x 50 mm so that the polycarbonate resin is on the lower side. The center was pressed at a speed of 10 mm / min, and the strength at which the test piece was broken was measured. The test was carried out three times, and the average value was taken as the measurement result.

[Processability]
Cut the test piece with a milling router (manufactured by Asahi Megaro Co., Ltd., FR500), visually observe the cut surface and the amount of chips adhering to it. The one with less adhesion was marked with Δ, and the one with much chip adhesion was marked with ×.

〔appearance〕
The reflected light of the surface was observed so that the surface of the substrate was reflected by the fluorescent light. The case where no rainbow pattern was observed was marked with ◯, and the case where the rainbow pattern was conspicuous was marked with x.

Example 2
Except that the curable paint (b2) was used instead of the curable paint (b1), the same operation as in Example 1 (2) was performed, and one side [on the acrylic resin (a1) layer] had a cured coating. A scratchable resin plate was obtained. The refractive index of the cured film was 1.538. The scratch-resistant resin plate was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 3
The substrate obtained in Example 1 (1) was cut into a size of 10 cm × 6 cm, immersed in the curable paint (b2), and pulled up at a speed of 5 mm / sec using a constant speed lifting device, A curable paint film was formed on both surfaces. Next, after drying at room temperature for 1 minute and further drying in a hot air oven at 45 ° C. for 10 minutes to volatilize the solvent, this coating film was subjected to 0.5 J / cm ² using a 120 W high-pressure mercury lamp. It was cured by irradiating with ultraviolet rays to obtain a scratch-resistant resin plate having a cured film on both sides. The scratch-resistant resin plate was evaluated as follows, and the results are shown in Table 1.

Example 4
To the scratch-resistant resin plate obtained in the same manner as in Example 2, no. A coating of curable paint (b3) was formed on the polycarbonate resin layer using a 20 bar coater. Next, after drying at room temperature for 1 minute and further drying in a hot air oven at 45 ° C. for 10 minutes to volatilize the solvent, this coating film was subjected to 0.5 J / cm ² using a 120 W high-pressure mercury lamp. It was cured by irradiating with ultraviolet rays to obtain a scratch-resistant resin plate having a cured film on both sides. The refractive index of the cured film on the polycarbonate resin layer was 1.584. The scratch-resistant resin plate was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1
Polycarbonate resin (Caliber 301-10 manufactured by Sumitomo Dow Co., Ltd.) was melt-kneaded using a 40 mmφ single screw extruder, then extruded through a T-shaped die, cooled so that both sides were completely in contact with the polishing roll, A polycarbonate resin single-layer substrate having a thickness of 0.5 mm was obtained. Using this substrate, the same operation as in Example 3 was performed to obtain a scratch-resistant resin plate having a cured coating film with a curable coating (b2) on both surfaces. The scratch-resistant resin plate was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2
Acrylic resin (a1) was melt-kneaded using a 40 mmφ single screw extruder, then extruded through a T-die, cooled so that both sides were completely in contact with the polishing roll, and a 0.5 mm thick acrylic resin unit A layered substrate was obtained. Using this substrate, the same operation as in Example 3 was performed to obtain a scratch-resistant resin plate having a cured coating film with a curable coating (b2) on both surfaces. The scratch-resistant resin plate was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3
A multilayer substrate having a thickness of 0.5 mm was obtained in the same manner as in Example 1 (1) except that the acrylic resin (a2) was used instead of the acrylic resin (a1). At this time, the thickness of the acrylic resin (a1) layer was 70 μm. Using this substrate, the same operation as in Example 3 was performed to obtain a scratch-resistant resin plate having a cured coating film with a curable coating (b2) on both surfaces. The scratch-resistant resin plate was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Claims (9)

A cured film is formed on at least one layer (B) of the substrate in which the layer (B) made of acrylic resin is laminated on at least one surface of the layer (A) made of polycarbonate resin, and the acrylic resin Is selected from methyl methacrylate units 60 to 95% by weight, methacrylic acid units, acrylic acid units, maleic anhydride units, N-substituted or unsubstituted maleimide units, glutaric anhydride structural units, and glutarimide structural units. A scratch-resistant resin plate characterized in that the glass transition temperature is 110 ° C. or higher.   The scratch-resistant resin plate according to claim 1, wherein the cured film formed on the layer (B) contains conductive particles.   The scratch-resistant resin plate according to claim 1 or 2, wherein the substrate is formed by laminating the layer (B) on one surface of the layer (A).   The scratch-resistant resin plate according to claim 3, wherein a cured film is formed on the layer (A).   The scratch-resistant resin plate according to claim 4, wherein the cured coating formed on the layer (A) contains conductive particles. The refractive index n of the cured film formed on the layer (A) and the refractive index ns of the layer (A) are expressed by the following formula: | n−ns | ≦ 0.01
The scratch-resistant resin plate according to claim 4 or 5, wherein: The scratch-resistant resin plate according to any one of claims 1 to 6 , wherein the substrate is formed by laminating the layer (A) and the layer (B) by coextrusion molding.   A display window protection plate for a portable information terminal comprising the scratch-resistant resin plate according to claim 1.   A protective plate for a display comprising the scratch-resistant resin plate according to claim 1.