JP2013195483A - Display protective plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display protective resin plate capable of suppressing coloring of an image when seen through a polarization filter such as polarized sunglasses, and polarized glasses, capturing of external light, and blur of the image.SOLUTION: A display protective resin plate of the present invention includes an irregular surface having the arithmetic average roughness (Ra1) of 0.1 to 0.3 μm on one surface of the resin plate; and the sum of the arithmetic average roughness of the other surface (Ra2) and Ra1 is less than 0.5 μm, haze of the resin plate is 7 to 30%, and a retardation value in the surface is 0 to 20 nm.

Description

  The present invention relates to a resin plate for protecting a display.

  As a resin plate for protecting a display, Patent Document 1 includes a thermoplastic resin substrate having a mat surface on one side, and the surface of the mat surface has an arithmetic average roughness (Ra) of 0.05 to 0.4 μm. Are disclosed, and a display-protecting resin plate having a haze (H) of 0.5 to 5% is disclosed. Patent Document 2 discloses a laminate for protecting a liquid crystal display in which polycarbonate resin layers are laminated on both sides of an acrylic resin layer.

JP 2011-232435 A JP 2011-232504 A

  Normally, the screen of the display is viewed with the naked eye, but a display used outdoors or a vehicle-mounted display may be viewed with polarized sunglasses. The angle formed by the polarization axis of the emitted light and the transmission axis of the polarized sunglasses when the screen of the display is viewed from the front when the polarizing plate is worn and the resin plate protecting the display is installed on the front side (viewer side) of the display Depending on the case, the screen may be colored and the visibility may be lowered. Even when the screen is not colored when viewed from the front direction, the screen may be colored and visibility may be reduced when the screen is viewed from an oblique direction.

  In a three-dimensional (3D) type display, polarized glasses are used to view the screen of the 3D display. A resin plate that protects the display is installed on the front side (viewer side) of the 3D display, and the resin plate When the screen of the 3D display is viewed from the front direction through the screen, the screen may appear colored depending on the angle formed by the polarization axis of the emitted light and the transmission axis of the polarizing glasses. Even when the screen is not colored when viewed from the front, the screen may appear colored when viewed from an oblique direction.

The resin plate that protects the display is installed on the front side (viewer side) of the display, and the display is viewed through it. The resin plate described in Patent Document 1 has irregularities on the surface of the resin plate to prevent Newton's rings from occurring. However, the resin plate described in Patent Document 2 is insufficient for reflection of external light. Although there is an effect of improving the visibility when the screen is viewed from an oblique direction, this is also not taken into consideration for reflection of outside light.
On the other hand, when the display is viewed through a resin plate protecting the display, an image displayed on the display may appear blurred.

  Accordingly, an object of the present invention is to provide a display protective resin plate that can suppress coloring of an image when viewed through a polarizing filter such as polarized sunglasses or polarized glasses, suppress reflection of external light, and suppress blurring of the image. Is to provide.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a solution means having the following constitution and have completed the present invention.
(1) An uneven surface having an arithmetic average roughness (Ra1) of 0.1 to 0.3 μm exists on one surface of the resin plate, and the sum of the arithmetic average roughness (Ra2) and Ra1 of the other surface is 0. A resin plate for display protection, wherein the resin plate has a haze of 7 to 30% and an in-plane retardation value of 0 to 20 nm.
(2) The resin plate for display protection according to (1), wherein the resin plate is made of a methyl methacrylate resin.
(3) The resin plate is formed by laminating a mat layer on a thermoplastic resin substrate, the mat layer is made of a thermoplastic resin containing transparent particles, and the uneven surface is formed by the mat layer ( The resin plate for display protection as described in 1).
(4) The resin plate according to any one of (1) to (3), wherein the display is a 3D display.

  According to the present invention, it is possible to obtain a display-protecting resin plate that suppresses coloring of a display image even through a polarizing filter such as polarized sunglasses, polarized glasses, etc., reduces reflection of external light, and suppresses image blurring. It is done. Therefore, the resin plate for display protection of the present invention can be easily applied to a display used outdoors or a 3D type display.

It is a schematic explanatory drawing which shows one Embodiment of the manufacturing method of the resin plate for display protection of this invention.

<Resin plate for display protection>
Hereinafter, an embodiment of the resin plate for display protection of the present invention (hereinafter sometimes referred to as “resin plate”) will be described.
The resin plate of this embodiment is provided with an uneven surface on at least one surface thereof. An uneven surface means a surface on which fine unevenness is formed on the surface. That is, the resin plate of the present embodiment has irregularities with an arithmetic average roughness (Ra1) of 0.1 to 0.3 μm, preferably 0.15 to 0.3 μm, more preferably 0.15 to 0.25 μm. Has an uneven surface (hereinafter, sometimes referred to as “Ra1 surface”). Further, the other surface (hereinafter sometimes referred to as “Ra2 surface”) which is the side surface opposite to the Ra1 surface may be matted, in which case the arithmetic average roughness (Ra2) of the surface is Ra1. And less than 0.5 μm, preferably less than 0.3 μm. The surface with the higher arithmetic average roughness (Ra) is defined as the Ra1 surface.
The haze (H) of the resin plate is 7 to 30%, preferably 10 to 25%, more preferably 10 to 20%.
Furthermore, the in-plane retardation value is 0 to 20 nm, preferably 1 to 15 nm, and more preferably 1 to 12 nm.
Since the resin plate of this embodiment has Ra1, the sum of Ra2 and Ra1, the haze, and the in-plane retardation value within the above range, the coloring of the image of the display is suppressed even through a polarizing filter such as polarized sunglasses, There is little reflection of external light, image blurring can be suppressed, and reflection of external light can be reduced even in an outdoor display.

On the other hand, if the arithmetic average roughness (Ra) is too small, the haze value becomes small and the reflection of external light becomes large. On the other hand, if the arithmetic average roughness (Ra) is too large, the image projected on the display is blurred and the visibility is lowered.
If the haze (H) is too small, reflection of external light may increase. On the other hand, if the haze (H) is too large, the image projected on the display may be blurred and the visibility may be lowered.
If the in-plane retardation value of the resin plate exceeds 20 nm, the screen becomes dark or colored when viewed through a polarizing filter.
The arithmetic average roughness (Ra) is a value measured according to JIS B0601-2001, and the same applies to the arithmetic average roughness described later. Haze (H) is a value measured according to JIS K7361-1. The in-plane retardation value of the resin plate is a value measured in the same manner as the method described in the examples.

  The thickness of the resin plate is usually 0.1 to 3 mm, preferably 0.2 to 2 mm, more preferably 0.3 to 1.5 mm.

  The resin plate of the present embodiment has a Ra1 surface and a Ra2 surface, and the layer configuration is not particularly limited as long as the haze and the in-plane retardation value are within the above ranges, and is a single layer body made of a thermoplastic resin. Alternatively, it may be a laminate including a thermoplastic resin substrate and a mat layer containing transparent particles laminated on the thermoplastic resin substrate (hereinafter sometimes simply referred to as a mat layer). When the resin plate is a laminate, the resin plate may be a laminate comprising a thermoplastic resin substrate and a mat layer laminated on one surface of the thermoplastic resin substrate, or a thermoplastic resin. A laminate comprising a substrate and a mat layer laminated on both surfaces of the thermoplastic resin substrate may be used. In the former case, the Ra1 surface may be the surface of the thermoplastic resin substrate, or the mat. It may be the surface of the layer. In particular, the resin plate is a laminate composed of a thermoplastic resin substrate and a mat layer laminated on one surface of the thermoplastic resin substrate, and the Ra1 surface is preferably the surface of the mat layer.

<Thermoplastic resin>
When the resin plate is a single layer, the thermoplastic resin constituting the resin plate contains a methyl methacrylate resin, a styrene resin, a polycarbonate resin, and an alicyclic structure-containing ethylenically unsaturated monomer unit. It is preferably at least one selected from resins, and more preferably a methyl methacrylate resin.
When the resin plate is a laminate, the thermoplastic resin constituting the thermoplastic resin substrate and the thermoplastic resin constituting the mat layer are the same as those exemplified as the thermoplastic resin constituting the single-layer resin plate. Can be mentioned. All of these resins have a low haze (H) and are therefore preferable in that they have a small effect on the image displayed on the display. In particular, methyl methacrylate resins are more preferable because the in-plane retardation value can be reduced. Note that the thermoplastic resin constituting the thermoplastic resin substrate and the thermoplastic resin constituting the mat layer may have the same or different compositions.
Moreover, you may add 1 type (s) or 2 or more types, for example, additives, such as a light stabilizer, a ultraviolet absorber, antioxidant, a flame retardant, and an antistatic agent, to a thermoplastic resin as needed.

  The methyl methacrylate resin, which is an example of a thermoplastic resin constituting the resin plate, is mainly composed of methyl methacrylate units, and may be a methyl methacrylate homopolymer, or methyl methacrylate, It may be a copolymer with another monomer that can be copolymerized with the methyl methacrylate. Specifically, the methyl methacrylate unit is usually contained in an amount of 50% by weight or more, preferably 70% by weight or more.

  Other monomers that can be copolymerized with methyl methacrylate include, for example, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate. Methacrylic acid esters other than methyl methacrylate such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, etc. Acrylic esters; styrene; halogenated styrenes such as chlorostyrene and bromostyrene; substituted styrenes such as vinyltoluene and alkylstyrenes such as α-methylstyrene; Sum acids; acrylonitrile, methacrylonitrile, maleic anhydride, phenyl maleimide, cyclohexyl maleimide, and the like. These other monomers that can be copolymerized with methyl methacrylate may be used alone or in combination of two or more.

The methyl methacrylate resin may contain rubber particles. Thereby, the impact resistance of the resin plate can be improved.
Examples of the rubber particles include an acrylic multilayer polymer, a graft copolymer obtained by graft-polymerizing 20 to 95 parts by weight of an ethylenically unsaturated monomer to 5 to 80 parts by weight of a rubbery polymer, and the like. It is done.

  The acrylic multilayer structure polymer which is an example of the rubber particles preferably has an elastomer layer of about 20 to 60% by weight, more preferably has a hard layer as the outermost layer, and more preferably the outermost layer. It has a hard layer as an inner layer.

  The elastomer layer is preferably an acrylic polymer layer having a glass transition point (Tg) of less than 25 ° C., specifically, lower alkyl acrylate, lower alkyl methacrylate, lower alkoxyalkyl acrylate, cyanoethyl acrylate, acrylamide. A polymer obtained by crosslinking one or more monofunctional monomers selected from the group consisting of 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 layer.

Examples of the lower alkyl group in the lower alkyl acrylate, lower alkyl methacrylate, hydroxy lower alkyl acrylate and hydroxy lower alkyl methacrylate include, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, t-butyl group, pentyl group, hexyl. Examples thereof include linear or branched alkyl groups having 1 to 6 carbon atoms such as groups.
As the lower alkoxy group in the lower alkoxyalkyl acrylate, for example, a straight chain having 1 to 6 carbon atoms such as methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, t-butoxy group, pentyloxy group, hexyloxy group, etc. Examples include a chain or branched alkoxy group. Further, when the copolymer is mainly composed of a monofunctional monomer, other monofunctional monomers such as styrene and substituted styrene may be copolymerized as the copolymer component.

The hard layer is preferably 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.
Examples of the alkyl group having 1 to 4 carbon atoms include linear or branched alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and a t-butyl group.

When the hard layer is made of a copolymer mainly composed of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, as the copolymer component, other alkyl methacrylate, alkyl acrylate, styrene, substituted styrene, acrylonitrile A monofunctional monomer such as methacrylonitrile may be used, or a polyfunctional monomer such as allyl methacrylate may be added to form a crosslinked polymer.
Examples of the alkyl group in alkyl methacrylate and alkyl acrylate include the same linear or branched alkyl groups having 1 to 6 carbon atoms as those exemplified as the lower alkyl group in the lower alkyl acrylate described above.

  The above-mentioned acrylic multilayer structure polymer is described in, for example, JP-B-55-27576, JP-A-6-80739, JP-A-49-23292, and the like.

  The graft copolymer which is an example of rubber particles is 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 diene rubbers such as polybutadiene rubber, acrylonitrile / butadiene copolymer rubber and styrene / butadiene copolymer rubber; acrylics such as polybutyl acrylate, polypropyl acrylate and poly-2-ethylhexyl acrylate. Rubbers such as ethylene / propylene / non-conjugated diene rubbers.
Examples of the ethylenically unsaturated monomer used for graft copolymerization with the rubbery polymer constituting the graft copolymer include acrylic unsaturated monomers, styrene, acrylonitrile, alkyl (meth). An acrylate etc. are mentioned. These graft copolymers are described, for example, in JP-A Nos. 55-147514 and 47-9740.

  The amount of the rubber particles used is usually 3 to 150 parts by weight, preferably 4 to 50 parts by weight, and more preferably 5 to 30 parts by weight with respect to 100 parts by weight of the methyl methacrylate resin. The greater the amount of rubber particles used, the better the impact resistance of the resulting resin plate, and it tends to be difficult to crack even when pressed, but if the amount of rubber particles used is too large, the surface hardness of the resulting resin plate Is unfavorable because it decreases.

  Examples of the polycarbonate resin which is an example of the thermoplastic resin constituting the resin plate 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 a polymer by a solid phase transesterification 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) It is preferable to use a dihydric phenol selected from −3,3,5-trimethylcyclohexane and α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene alone or in combination of two or more. Of 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane and bisphenol A, one or more dihydric phenols selected from 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane and α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene Use in combination 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.

  A styrene resin, which is an example of a thermoplastic resin constituting a resin plate, is a polymer containing 50% by weight or more of a styrene monofunctional monomer unit, and is a homopolymer of a styrene monofunctional monomer. It may be a styrene monofunctional monomer or a copolymer of a monofunctional monomer copolymerizable therewith.

Examples of styrene monofunctional monomers include styrene skeletons such as styrene, halogenated styrenes such as chlorostyrene and bromostyrene, and substituted styrenes such as alkyltoluenes such as vinyltoluene and α-methylstyrene. And a compound having one double bond capable of radical polymerization in the molecule.
A monofunctional monomer that can be copolymerized with a styrenic monofunctional monomer has one double bond capable of radical polymerization in the molecule, and this double bond is used to make a styrenic monofunctional monomer. For example, methacrylic acid such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, etc. 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; acrylonitrile, etc. Such as methyl methacrylate Methacrylic acid esters are preferably used. These monofunctional monomers are used alone or in combination of two or more.

  A resin containing an alicyclic structure-containing ethylenically unsaturated monomer unit, which is an example of a thermoplastic resin constituting the resin plate, is characterized by containing an alicyclic structure in the repeating unit of the polymer. At least one selected from the main chain and the side chain may have an alicyclic structure, but from the viewpoint of light transmittance, those containing an alicyclic structure in the main chain are preferred.

  Examples of the resin containing an alicyclic structure-containing ethylenically unsaturated monomer unit include a norbornene polymer, a monocyclic olefin polymer, a cyclic conjugated diene polymer, and a vinyl alicyclic hydrocarbon polymer. And coalesced and hydrogenated products thereof. Among these, from the viewpoint of light transmittance, a norbornene polymer hydrogenated product, a vinyl alicyclic hydrocarbon polymer and a hydride thereof are preferable, and a norbornene polymer hydrogenated product is more preferable.

<Matte layer>
The mat layer is made of a thermoplastic resin containing transparent particles, and an uneven surface is formed on the surface of the mat layer. That is, unevenness derived from the transparent particles is formed on the surface of the mat layer, and the unevenness having a specific arithmetic average roughness (Ra) is formed by the unevenness.

(Transparent particles)
Examples of the transparent particles constituting the mat layer include organic particles such as methyl methacrylate polymer particles, styrene polymer particles, and siloxane polymer particles; calcium carbonate, barium sulfate, titanium oxide, aluminum hydroxide, Examples include inorganic particles such as silica (silicon oxide), inorganic glass, talc, mica, white carbon, magnesium oxide, and zinc oxide. These may be used alone or in combination of two or more. The inorganic particles may be surface-treated with a surface treatment agent such as a fatty acid so as to be uniformly dispersed in the thermoplastic resin.

  In order to control the haze (H) value of the resin plate within the above range, the transparent particles preferably have a difference in refractive index from the thermoplastic resin constituting the mat layer and the thermoplastic resin layer. Usually, it is preferable that the refractive index difference is within about 0.1. From such a viewpoint, the transparent particles are preferably organic particles such as methyl methacrylate polymer particles, styrene polymer particles, and siloxane polymer particles.

  An example of transparent particles is a methyl methacrylate polymer particle, which is a polymer particle mainly composed of methyl methacrylate, and one double bond capable of radical polymerization in the other molecule. Preferred are crosslinked methyl methacrylate polymer particles, which are crosslinked polymers obtained by copolymerizing a monofunctional monomer having a polyfunctional monomer having two or more double bonds capable of radical polymerization in the molecule. .

  Examples of the monofunctional monomer include those exemplified as other monomers that can be copolymerized with methyl methacrylate constituting the methyl methacrylate resin, and among them, styrene is preferable.

  Examples of the polyfunctional monomer include 1,4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, propylene ethylene glycol dimethacrylate, and tetrapropylene ethylene glycol. Methacrylates of polyhydric alcohols such as dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate; 1,4-butanediol diacrylate, neopentyl glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, tetraethylene glycol di Acrylate, propylene ethylene glycol diacryl Methacrylates, polyhydric alcohol methacrylates such as tetrapropylene ethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate; aromatic polyfunctional compounds such as divinylbenzene and diallyl phthalate, and the like. Alternatively, two or more kinds may be mixed and used.

  The refractive index of methyl methacrylate polymer particles is usually about 1.46 to 1.55, and the higher the benzene skeleton and halogen atom content, the higher the refractive index. The methyl methacrylate polymer particles can be produced, for example, by a suspension polymerization method, a micro suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, or the like.

  Styrene polymer particles as an example of transparent particles are polymer particles mainly composed of styrene, and a monofunctional monomer having one double bond capable of radical polymerization in styrene and other molecules. Crosslinked styrene polymer particles, which are crosslinked polymers obtained by copolymerizing a polyfunctional monomer having two or more double bonds capable of radical polymerization in the molecule, are preferred.

  Examples of monofunctional monomers other than styrene in the styrene polymer particles include, for example, methyl methacrylate and other monomers that can be copolymerized with methyl methacrylate constituting the methyl methacrylate resin Among them, methyl methacrylate is preferable.

  Examples of the polyfunctional monomer in the styrene polymer particles include the same polyfunctional monomers as those exemplified for the methyl methacrylate polymer particles.

  The refractive index of the styrenic polymer particles is usually about 1.53 to 1.61, and the larger the benzene skeleton or halogen atom content, the larger the refractive index tends to be exhibited. Styrene polymer particles can be produced, for example, by suspension polymerization, micro suspension polymerization, emulsion polymerization, dispersion polymerization, or the like.

  The ratio of the polyfunctional monomer in the above-mentioned methyl methacrylate polymer particles and styrene polymer particles is usually about 0.05 to 15% by weight, preferably 0.1% based on the total monomers. -10% by weight. If the amount of the polyfunctional monomer is too small, the particles are not sufficiently crosslinked, and the particles may be deformed when heat or shearing force is applied in the extrusion molding described later. Moreover, when there is too much quantity of a polyfunctional monomer, an external appearance defect will generate | occur | produce easily at the time of extrusion molding.

  Examples of the siloxane polymer particles as an example of the transparent particles include siloxane polymer particles obtained by hydrolyzing and condensing chlorosilanes; curable polymers having linear organosiloxane blocks and compositions thereof. Examples include granular particles obtained by curing in a sprayed state; granular particles obtained by hydrolytic condensation of alkyltrialkoxysilane or a partially hydrolyzed condensate thereof in an aqueous solution of ammonia or amines.

Examples of chlorosilanes include dimethyldichlorosilane, diphenyldichlorosilane, phenylmethyldichlorosilane, methyltrichlorosilane, and phenyltrichlorosilane.
The siloxane polymer may be cross-linked. For crosslinking, for example, siloxane-based polymer is benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl-2,5-dimethyl peroxide. A peroxide such as -2,5- (t-butylperoxy) hexane may be allowed to act. When the siloxane polymer has a terminal silanol group, it may be subjected to condensation crosslinking with alkoxysilanes. The crosslinked siloxane-based polymer preferably has a structure in which about 2 to 3 organic residues are bonded per silicon atom.
The siloxane-based polymer is a polymer also called a silicone rubber or a silicone resin, and is preferably a solid at room temperature.
Siloxane polymer particles can be obtained by pulverizing a siloxane polymer. The refractive index of the siloxane polymer particles is usually about 1.40 to 1.47.

  Particularly preferred transparent particles are at least one selected from crosslinked methyl methacrylate polymer particles and crosslinked styrene polymer particles. Commercially available products can be used. For example, MBX series, which is a crosslinked methyl methacrylate polymer particle manufactured by Sekisui Plastics Co., Ltd., SBX series, which is a crosslinked styrene polymer particle, and the like. Can be mentioned.

  The average particle diameter of the transparent particles is preferably 3 to 50 μm, more preferably 2 to 30 μm, and further preferably 3 to 20 μm. The shape of the transparent particles is usually spherical, but may be, for example, a rectangular shape, a scale shape, a needle shape, a plate shape, or the like.

  The content of the transparent particles is preferably 1 to 30 parts by weight, and more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the thermoplastic resin constituting the mat layer. When the content ratio of the transparent particles is too small, it is difficult to form irregularities derived from the transparent particles on the surface of the mat layer, and the arithmetic average roughness (Ra1) of the irregular surfaces may be less than 0.1 μm. On the other hand, when the ratio of the transparent particles is too large, extrusion molding becomes difficult and the arithmetic average roughness (Ra1) of the uneven surface may exceed 0.3 μm, which is not preferable.

  The thickness of the mat layer is usually 0.01 to 1 mm, preferably 0.01 to 0.5 mm. The smaller the mat layer thickness, the better the impact resistance of the resin plate, and it tends to be difficult to break even when pressed. However, if the mat layer thickness is too small, unevenness in the dispersion of transparent particles in the mat layer occurs. However, it is not preferable because the appearance may be impaired.

<Hard coat treatment>
The Ra1 surface may be subjected to a hard coat treatment. Thereby, the scratch resistance of the Ra1 surface can be improved. On the other hand, when the hard coat treatment is applied to the Ra1 surface, the arithmetic average roughness and the haze (H) tend to decrease. Therefore, the hardness is set so that the sum of Ra1, Ra1 and Ra2 and the haze are within the above range. It is necessary to apply a coating treatment. You may perform a hard-coat process to Ra2 surface. Thereby, the scratch resistance of the Ra2 surface can be improved.

Examples of the hard coat treatment include a method of forming a cured film on a resin plate. When a cured film is formed on the resin plate, the cured film may be formed as in any one of (i) to (iii) below.
(I) Cured coating / Ra1 surface of resin plate / Ra2 surface of resin plate (ii) Cured coating / Ra1 surface of resin plate / Ra2 surface of resin plate / cured coating (iii) Ra1 surface of resin plate / Ra2 of resin plate Surface / cured film When the cured film is formed on both surfaces of the resin plate, the composition and thickness of the cured film on both surfaces may be the same or different from each other.

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

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 and compounds having a (meth) acryloyloxy group. 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 in water relative to the isocyanato group Urethane (meth) acrylate obtained by reacting at a ratio of at least equimolar groups 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.

  A commercially available compound can be used as the compound having at least three (meth) acryloyloxy groups in the molecule, for example, “NK Hard M101” (urethane acrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. System), "NK ester A-TMM-3L" (pentaerythritol triacrylate), "NK ester A-TMMT" (pentaerythritol tetraacrylate), "NK ester A-9530" (dipentaerythritol pentaacrylate) and "NK Ester A-DPH "(dipentaerythritol hexaacrylate)," KAYARAD DPCA "(dipentaerythritol hexaacrylate) manufactured by Nippon Kayaku Co., Ltd. "Unidic" series manufactured by Etc. The.

  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. 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, the curable coating composition may contain a photopolymerization initiator 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.

  Commercially available photopolymerization initiators can be used. For example, “IRGACURE 651”, “IRGACURE 184”, “IRGACURE 500”, “IRGACURE 1000”, “Ciba Specialty Chemicals Co., Ltd.” IRGACURE CUDA (IRGACURE 812) such as IRGACURE 2959, "DAROCUR 1173", "IRGACURE 907", "IRGACURE 369", "IRGACURE 1700", "IRGACURE 1800", "IRGACURE 819", "IRGACURE 784" ) Series, all manufactured by Nippon Kayaku Co., Ltd. “KAYACURE ITX”, “KAYACURE DETX-S”, “KAYACURE BP-100”, “KAYACUREBMS”, “KAYA” URE 2-EAQ "such as, KAYACURE (Kayacure) series, and the like.

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

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

  The usage-amount of electroconductive particle is 2-50 weight part normally with respect to 100 weight part of sclerosing | hardenable 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 preferably contains a solvent for the purpose of adjusting the viscosity thereof, and in particular when conductive particles are contained, a 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 this dispersion is used as a curable compound. You may mix, and after mixing a sclerosing | hardenable compound and a solvent, you may disperse | distribute electroconductive particle to this liquid mixture.

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 coating component. There should 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 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; water and the like.
What is necessary is just to adjust the usage-amount of a solvent suitably according to the property etc. of a curable compound.

Silicone oil is preferably used when the curable coating composition contains a leveling agent.
Examples of the silicone oil 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 silicone oil, fluorine-modified silicone oil, poly Examples include ether-modified silicone oil. 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.

  A commercially available leveling agent can be used, for example, “SH200-100cs”, “SH28PA”, “SH29PA”, “SH30PA”, “ST83PA” manufactured by Toray Dow Corning Silicone Co., Ltd., “ST80PA”, “ST97PA” and “ST86PA” are all listed as “BYK-302”, “BYK-307”, “BYK-320”, “BYK-330”, etc. manufactured by Big Chemie Japan Co., Ltd. It is done.

The curable coating composition thus obtained is applied to at least one surface of the resin plate to form a curable coating film, and the cured coating film can be formed by curing the curable coating film.
The curable coating composition 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. Conditions such as intensity and irradiation time are appropriately selected according to the type of curable coating composition. The
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 plate 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 coating 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.

  If necessary, the obtained resin plate may be subjected to an antireflection treatment by a coating method, a sputtering method, a vacuum deposition method, or the like. Further, an antireflection sheet prepared separately may be bonded to one or both sides of the resin plate to give an antireflection effect.

  The resin plate is suitably used as a protective plate for the display. Examples of the type of display to be protected include a CRT display, a liquid crystal display, a plasma display, an EL display, an LED display, a 3D display using these displays, and the like. 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. Examples include a finder part of a portable video camera and a display window of a portable game machine, and it is particularly suitable for a large-sized 3D display installed outdoors.

  In order to protect the display using the resin plate of the present embodiment, first, the resin plate is subjected to processing such as printing and drilling as necessary, and then cut to a required size. Thereafter, if the resin plate is set on the display, the display can be effectively protected. In that case, it is preferable to arrange the uneven surface on the viewer side. Thereby, generation | occurrence | production of the reflection by reflection of external light can be suppressed.

<Method for producing resin plate>
As a method for producing a resin plate, for example, a method of laminating a mat layer containing transparent particles on a thermoplastic resin substrate (A); a method of transferring irregularities with a cooling roll or the like while the resin is melted and softened (B Among them, the method (A) is preferable because the retardation value of the obtained resin plate can be easily reduced.
Examples of the method (A) include a coextrusion molding method; a method of laminating and integrating by bonding using a pressure sensitive adhesive or an adhesive, among others, bonding using a pressure sensitive adhesive or an adhesive. The coextrusion molding method is preferable in terms of easy secondary molding as compared with the resin plate produced by the above method.

An embodiment of a method for producing a resin plate by coextrusion molding will be described in detail with reference to FIG. In the present embodiment, it is essential to use a thermoplastic resin containing transparent particles as a raw material.
As shown in the figure, first, a thermoplastic resin and a thermoplastic resin containing transparent particles are heated and melted and kneaded by separate extruders 1 and 2, respectively, supplied to the feed block 3, and melt laminated integrally. After forming, it is extruded from the die 4 and laminated and integrated.

  Next, the sheet-shaped or film-shaped molten resin 5 extruded from the die 4 is sandwiched between the cooling roll 6 and the cooling roll 7, wound around the cooling roll 7, and then gently wound around the cooling roll 8. Molding / cooling is performed, and the transport roll is taken up by a take-up roll (not shown) to obtain a resin plate 9. The thickness of the resin plate 9 obtained can be adjusted by adjusting the thickness of the molten resin 5, the intervals between the cooling rolls 6 to 8, the peripheral speed, and the like.

  At least one of the cooling rolls 6 and 7 is connected to rotation driving means such as a motor, and both rolls are configured to rotate at a predetermined peripheral speed. Among the two rolls, the cooling roll 7 is a winding roll around which a sheet-like or film-like molten resin after being sandwiched between the two rolls is wound.

  Examples of the cooling rolls 6 to 8 (hereinafter sometimes collectively referred to as cooling rolls) include a rigid metal mirror roll, an elastic metal elastic roll, and a mat roll. In order to set the retardation value of the obtained resin plate within the above range, it is preferable to use a metal elastic roll.

The metal mirror roll may be a mirror-polished metal roll.
The arithmetic average roughness of the metal mirror surface is usually 0.001 to 0.1 μm, preferably 0.005 to 0.08 μm, and more preferably 0.01 to 0.05 μm.

The metal elastic roll 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 is in contact with the molten resin 5, and between the shaft roll and the metal thin film. And a material in which a temperature-controlled fluid such as water or oil is enclosed, or a metal belt wrapped around the surface of a rubber roll.
The arithmetic average roughness of the metal elastic roll surface is usually 0.001 to 0.1 μm, preferably 0.005 to 0.08 μm, and more preferably 0.01 to 0.05 μm.

The mat roll is a roll having a concavo-convex shape formed on the outer peripheral surface, and examples thereof include a metal roll such as a drilled roll or a spiral roll having a concavo-convex shape formed on the outer peripheral surface. The reverse pattern of the uneven shape of the mat roll is an uneven shape formed on the surface of the uneven surface.
The arithmetic average roughness of the mat roll surface is usually 0.3 to 5 μm, preferably 0.5 to 3 μm, more preferably 0.5 to 2 μm.
The uneven shape of the mat roll can be formed, for example, by blasting, engraving, laser processing, or the like.

  As the combination of the cooling rolls, the cooling roll 6 / cooling roll 7 / cooling roll 8 is a metal mirror roll / metal elastic roll / metal mirror roll, metal elastic roll (or rubber roll) / metal mirror roll / metal mirror roll, metal elasticity. A roll (or rubber roll) / metal mirror roll / metal elastic roll is preferred.

  For example, when the cooling rolls 6 and 7 are combined with a metal roll and a metal elastic roll, a resin plate with reduced strength and anisotropy of heat shrinkage can be obtained. That is, when the molten resin 5 is sandwiched between the metal roll and the metal elastic roll, the metal elastic roll is elastically deformed into a concave shape along the outer peripheral surface of the metal roll via the molten resin 5, and the metal elastic roll and the metal roll Is contacted through the molten resin 5 with a predetermined contact length. As a result, the metal roll and the metal elastic roll come into pressure contact with the molten resin 5 by surface contact, and the molten resin 5 sandwiched between these rolls is formed into a film while being uniformly pressed into a planar shape. . As a result, a resin plate with reduced distortion during film formation and reduced strength and thermal shrinkage anisotropy can be obtained.

  In order to form an uneven surface using a mat roll, for example, a mat roll may be adopted as the second cooling roll 6 and extrusion molding may be performed. In addition, the formation method of the uneven surface using a mat roll is described in Unexamined-Japanese-Patent No. 2009-196327, Unexamined-Japanese-Patent No. 2009-202382, etc., for example.

<Other embodiment of the manufacturing method of a resin board>
When a resin plate is manufactured using a thermoplastic resin that does not contain transparent particles as a raw material, the above-described <Manufacturing of a resin plate is performed except that one or two of the cooling rolls 6 to 8 is a mat roll. In the same manner as in the embodiment of the method, a resin plate can be produced.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example. In the following examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified.

The structure of the extrusion apparatus used in the following examples and comparative examples is as follows.
Extruder 1: An extruder with a screw diameter of 65 mm, a single screw, and a vent (manufactured by Toshiba Machine Co., Ltd.) was used.
Extruder 2: An extruder with a screw diameter of 45 mm, a single screw, and a vent (manufactured by Hitachi Zosen Corporation) was used.
Feed block 3: A 2-type 3-layer distribution type or 2-type 2-layer distribution type feed block (manufactured by Hitachi Zosen Corporation) was used.
Die 4: A T-die (manufactured by Hitachi Zosen Corporation) having a lip width of 1400 mm and a lip interval of 1 mm was used.
Cooling rolls 6, 7, 8: The rolls shown in the following roll configuration were used. All the rolls are horizontal, have a surface length of 1400 mm, and a diameter of 300 mmφ.

The following four types of roll configurations were used.
Configuration 1: Cooling rolls 6, 8 / metal elastic roll, cooling roll 7 / metal mirror roll configuration 2: Cooling rolls 6-8 / metal mirror roll configuration 3: Cooling roll 6 / rubber roll, cooling roll 7 / Ra = 2.5 μm Mat roll, cooling roll 8 / metal elastic roll Configuration 4: cooling roll 6, 8 / metal elastic roll, cooling roll 7 / Matte roll with Ra = 0.4 μm

As the metal elastic roll, a metal thin film is disposed so as to cover the outer peripheral surface of the shaft roll, and a fluid is sealed between the shaft roll and the metal thin film. The arithmetic average roughness (Ra) of the metal elastic roll surface is 0.03 μm.
The shaft roll, metal thin film and fluid are as follows.
Shaft roll: stainless steel Metal thin film: 2 mm thick stainless steel mirror surface metal sleeve Fluid: Oil. By controlling the temperature of this oil, the temperature of the metal elastic roll can be controlled. More specifically, the oil was heated and cooled by ON / OFF control of a temperature controller so that the temperature could be controlled and circulated between the shaft roll and the metal thin film.

The rubber roll used was a laminate of silicon rubber having a hardness of 80 mm around the metal shaft. The arithmetic average roughness (Ra) of the rubber roll surface is 1.2 μm.
As the mat roll, a metal roll having a concavo-convex structure by sandblasting and Cr plating was used.
The metal mirror roll is a stainless steel spiral roll having a mirror surface. The arithmetic mean roughness (Ra) of the metal mirror surface is 0.02 μm.

Resins used in Examples and Comparative Examples are as follows.
<Resin>
Resin 1: Polycarbonate resin (“Caliber 301-10” manufactured by Sumitomo Dow)
Resin 2: Methacrylic resin containing transparent particles (resin 4 cross-linked polymethyl methacrylate particles (“MBX-5” manufactured by Sekisui Plastics Co., Ltd.) in 100 parts of resin 4 at the following ratio: Contained resin)
Resin 2-1: 2.5 parts of crosslinked polymethyl methacrylate particles
Resin 2-2: 5.0 parts of crosslinked polymethyl methacrylate particles
Resin 2-3: containing 7.5 parts of crosslinked polymethyl methacrylate particles
Resin 2-4: 9.0 parts of crosslinked polymethyl methacrylate particles
Resin 2-5: containing 15.0 parts of crosslinked polymethyl methacrylate particles
Resin 2-6: containing 1.0 part of crosslinked polymethyl methacrylate particlesResin 3: methacrylic resin ("Shock Resistant Grade Sumipex HT01X" manufactured by Sumitomo Chemical Co., Ltd.)
Resin 4: Methacrylic resin (“SUMIPEX MHF” manufactured by Sumitomo Chemical Co., Ltd.)

[Examples 1 to 4 and Comparative Examples 1, 2, and 6]
<Production of resin plate>
First, extruders 1, 2, and a two-type two-layer distribution type feed block 3, a die 4, and cooling rolls 6, 7, and 8 were arranged as shown in FIG. Next, the resin of the type shown in Table 1 as the resin layer A is melt-kneaded by the extruder 1, and the resin of the type shown in Table 1 as the resin layer B is melt-kneaded by the extruder 2 and supplied to the feed block 3 respectively. did.
Coextrusion molding was performed so that the resin layer B supplied from the extruder 2 to the feed block was laminated on one surface of the resin layer A supplied from the extruder 1 to the feed block.

  Next, the film-shaped molten resin 5 extruded from the die 4 is sandwiched between the cooling roll 6 and the cooling roll 7 that are arranged to face each other, and then wound around the cooling roll 7. Was molded and cooled to obtain a two-layered resin plate having the thickness shown in Table 1 in which the resin layer B was laminated on one surface of the resin layer A.

[Examples 5-8, 10-13 and Comparative Examples 3-5, 7, 8]
<Production of resin plate>
In the same manner as in Examples 1 to 4 and Comparative Examples 1, 2, and 6, except that the two-type two-layer distribution type feed block was changed to a two-type three-layer distribution type feed block, the resin layer A A resin plate having a three-layer structure having the thickness shown in Table 1 in which the resin layer B was laminated on both surfaces was obtained. The composition and thickness of the resin layers B on both surfaces of each obtained resin plate are the same.

[Examples 9, 14 to 16 and Comparative Example 9]
<Production of resin plate>
A single layer having only the resin layer A and having the thickness shown in Table 1 in the same manner as in Examples 1 to 4 and Comparative Examples 1, 2, and 6 except that the extruder 2 and the feed block 3 are not used. A resin plate having a structure was obtained.

<Evaluation>
About each obtained resin board, thickness, haze (H), arithmetic mean roughness (Ra1, 2), retardation value, coloring, visibility, and reflection were evaluated. Each evaluation method is shown below, and the results are shown in Table 1.

(Thickness)
The thickness in the extruders 1 and 2 is determined by measuring the total thickness of the obtained resin plate with a Digimatic standard outside micrometer “MDC-25M” (manufactured by Mitutoyo Corporation). It calculated by multiplying the supply amount ratio (extrusion amount ratio) of the resin supplied. The thicknesses of both surface layers in the three-layered resin plate were calculated by the following formula.
Thickness of both surface layers = total thickness of resin plate × {feed amount from extruder 2 / (feed amount of extruder 1 + feed amount of extruder 2)} ÷ 2

(Haze (H))
Based on JIS K7166-1, it measured with the haze and transmittance meter "HR-150" by Murakami Color Research Laboratory.

(Arithmetic mean roughness (Ra1, 2))
Based on JIS B0601-2001, the arithmetic average roughness (Ra) of both surfaces of the resin plate was measured using a surface roughness measuring device “Surfcom 550A” manufactured by Toyo Seimitsu Co., Ltd.

(Retardation value)
The retardation value at 590 nm was measured using an automatic birefringence meter “KOBRA-CCD / X” manufactured by Oji Scientific Instruments.

(Coloring when viewed from an oblique direction)
First, the surface of the resin plate obtained above having Ra of 0.1 to 0.3 μm, the case where Ra on both sides is 0.1 to 0.3 μm, or the case where both Ras are 0.1 to 0.1 μm. When the thickness was not 0.3 μm, the surface with the larger Ra and the surface of the first polarizing plate were overlapped. Next, the second polarizing plate was superposed on the other surface of the resin plate opposite to the surface where the surfaces of the first polarizing plate were superposed so that the first polarizing plate and the polarization axis were orthogonal to each other. As the first and second polarizing plates, “Sumikaran SG” manufactured by Sumitomo Chemical Co., Ltd. was used.
Then, while illuminating the surface of the second polarizing plate with light of a three-wavelength type fluorescent lamp (“Lupica Ace” manufactured by Mitsubishi Electric Osram Co., Ltd.), the second polarizing plate is obliquely inclined from about 45 degrees above the second polarizing plate. When the surface of the other surface of the resin plate was viewed through the surface, whether or not the surface of the other surface of the resin plate appeared colored was visually observed. The following criteria were used.
○: Colored and invisible.
Δ: Colored and invisible, but the difference in brightness is large depending on the installation angle of the plate.
X: It looks colored.

(Visibility)
When the surface of the resin plate obtained above is 0.1 to 0.3 [mu] m and the surface Ra of both surfaces are 0.1 to 0.3 [mu] m, the display is made to face the larger surface of Ra. When the resin plate is brought close to the display in the state and the distance between the resin plate and the display is 5 mm, it is visually observed whether the image displayed on the display viewed through the resin plate is blurred. And evaluated. In addition, the monitor used the monitor of the notebook personal computer ("LATITUDE E5400") by Dell. In addition, the following criteria were used.
Excellent: The image could be visually recognized without blurring.
Good: The image was slightly blurred, but there was no problem in visual recognition of the image.
Possible: The image was slightly blurred, but there was no problem in visual recognition of the image.
Impossibility: The image was blurred and it was difficult to visually recognize the image.

(Reflection)
When the visibility was evaluated, a fluorescent lamp on the ceiling was projected from an angle of 45 degrees to confirm the state of reflection on the screen.
Excellent: The outline of the fluorescent lamp was blurred, and the outline of the fluorescent lamp was not confirmed.
Good: The outline of the fluorescent lamp was blurred, but the outline of the fluorescent lamp was very slightly confirmed.
Possible: The outline of the fluorescent lamp was blurred, but the outline of the fluorescent lamp was slightly confirmed.
Impossibility: The outline of the fluorescent lamp was clearly confirmed without blurring the outline of the fluorescent lamp.

  In Table 1, “thickness” in the extruders 1 and 2 indicates the thickness of each of the resin layers A and B, and “total thickness” indicates the total thickness of the obtained resin plate.

DESCRIPTION OF SYMBOLS 1, 2 Extruder 3 Feed block 4 Die 5 Film-like molten resin 6, 7, 8 Cooling roll 9 Resin plate

Claims (4)

An uneven surface with an arithmetic average roughness (Ra1) of 0.1 to 0.3 μm exists on one surface of the resin plate,
And the sum of the arithmetic mean roughness (Ra2) and Ra1 of the other surface is less than 0.5 μm,
And the haze of a resin board is 7 to 30%, and the in-plane retardation value is 0 to 20 nm, The display protective resin board characterized by the above-mentioned.   2. The display-protecting resin plate according to claim 1, wherein the resin plate is made of a methyl methacrylate resin.   2. The resin plate is formed by laminating a mat layer on a thermoplastic resin substrate, the mat layer is made of a thermoplastic resin containing transparent particles, and the uneven surface is formed by the mat layer. Resin plate for display protection.   The resin plate according to claim 1, wherein the display is a 3D display.

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