JP2013193241A - Laminated plate and scratch-resistant laminated plate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated plate configured to prevent curvature deformation under a high temperature environment.SOLUTION: A laminated plate is formed by melting and coextruding a polycarbonate resin and an acrylic resin, and has a layer made of the acrylic resin at least on one surface of a layer made of the polycarbonate resin. A distance (L) from one surface of the polycarbonate resin layer in a thickness direction in a cross section orthogonal to an extruding direction is plotted on the X axis, and a difference (ΔN) between a birefringence (N) with respect to light having a wavelength of 546 nm at the distance (L) and a birefringence (N) with respect to the light having a wavelength of 546 nm at the distance (L) after heating the laminated plate at 80°C for one hour is plotted on the Y axis. An absolute value of a value of inclination in a linear expression of X and Y calculated by a least-squares method is not more than 0.3.

Description

  The present invention relates to a laminate formed by melt coextrusion of a polycarbonate resin and an acrylic resin, and having a layer made of an acrylic resin on at least one surface of the layer made of the polycarbonate resin. The present invention also relates to a scratch-resistant laminate using the laminate as a substrate. Furthermore, the present invention relates to a protective plate for display comprising this scratch-resistant laminate.

  Laminate with an acrylic resin layer on at least one side of a polycarbonate resin layer is excellent in transparency, impact resistance and surface hardness, lighting covers and signs, building materials and electrical products, mobile phones and LCD TVs It is widely used for optical applications such as Generally, the laminate is formed by melt coextrusion of a polycarbonate resin and an acrylic resin.

  Patent Document 1 discloses a laminated plate obtained by melt coextrusion molding of a polycarbonate resin and an acrylic resin, and provided with layers made of an acrylic resin on both sides of the layer made of the polycarbonate resin.

  Optical applications such as lighting covers, signboards, building materials, electrical products, mobile phones, and liquid crystal televisions are used in high-temperature environments, but the laminate disclosed in Patent Document 1 is warped and deformed in high-temperature environments. Arise.

Japanese Patent Laid-Open No. 11-058627

  The subject of this invention is providing the laminated board by which the curvature deformation in a high temperature environment is suppressed.

As a result of intensive studies to solve the above problems, the inventors of the present invention are formed by melt coextrusion of a polycarbonate resin and an acrylic resin, and a layer made of an acrylic resin is provided on at least one surface of the layer made of the polycarbonate resin. In the laminated plate, the birefringence of light with a wavelength of 546 nm at the distance (L) with the X axis as the distance (L) from one surface of the polycarbonate resin layer in the thickness direction in a cross section perpendicular to the extrusion direction and _{(N 0),} in said distance (L) after the laminated plate was heated for 1 hour at 80 ° C., and plotted the (.DELTA.N) in the Y-axis of the birefringence for light having a wavelength of 546 nm _{(N 1)} The present invention has found that the warp deformation in a high temperature environment can be suppressed by setting the absolute value of the slope value in the linear expression of X and Y calculated by the least square method to 0.3 or less. It has been completed.

That is, the present invention relates to the following inventions.
(1) Thickness in a cross-section formed by melt coextrusion of a polycarbonate resin and an acrylic resin and having a layer made of an acrylic resin on at least one surface of the layer made of the polycarbonate resin, in a cross section orthogonal to the extrusion direction The distance (L) from one surface of the polycarbonate resin layer in the direction is taken as the X axis, the birefringence (N ₀ ) with respect to light having a wavelength of 546 nm at the distance (L), In the linear expression of X and Y, the difference (ΔN) from the birefringence index (N ₁ ) with respect to light having a wavelength of 546 nm at the distance (L) after heating for a time is plotted on the Y axis and calculated by the least square method. A laminate having an absolute value of inclination of 0.3 or less.
(2) The laminate according to (1), wherein the thickness is 0.4 to 2.0 mm.
(3) A scratch-resistant laminate comprising a cured film formed on at least one surface of the laminate according to (1) or (2).
(4) A protective plate for a display comprising the laminated plate according to (1) or (2).

  According to the present invention, there is an effect that warpage deformation under a high temperature environment is suppressed.

These are the schematic explanatory drawings which show the manufacturing method of the laminated board which concerns on one embodiment of this invention.

  The laminate of the present invention is formed by melt coextrusion of a polycarbonate resin and an acrylic resin, and a layer made of an acrylic resin (hereinafter referred to as an acrylic resin) on at least one surface of a layer made of the polycarbonate resin (hereinafter referred to as a polycarbonate resin layer). A layer).

  Examples of the polycarbonate resin include those obtained by reacting a dihydric phenol and a carbonylating agent by an interfacial polycondensation method or a melt transesterification method, or by polymerizing a carbonate prepolymer by a solid phase transesterification method or the like. What is obtained, what is obtained by polymerizing a cyclic carbonate compound by a ring-opening polymerization method, etc. are mentioned.

  Examples of the dihydric phenol include hydroquinone, resorcinol, 4,4′-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, bis {(4-hydroxy-3,5-dimethyl) phenyl} methane, 1,1- Bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A), 2,2-bis { (4-hydroxy-3-methyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dimethyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dibromo) ) Phenyl} propane, 2,2-bis {(3-isopropyl-4-hydroxy) phenyl} propane, 2,2-bis {( -Hydroxy-3-phenyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl) ) -3,3-dimethylbutane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl)- 4-methylpentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3 , 5-trimethylcyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis {(4-hydroxy -3-methyl) phenyl} fluorene, α, α′-bis (4-hydroxyphenyl) -o-diisopropylbenzene, α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene, α, α′- Bis (4-hydroxyphenyl) -p-diisopropylbenzene, 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane, 4,4′-dihydroxydiphenylsulfone, 4,4′-dihydroxydiphenylsulfoxide, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxydiphenyl ketone, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl ester, and the like, and two or more of them are used as necessary. You can also.

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

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

  A thermoplastic resin other than the polycarbonate resin may be mixed with the polycarbonate resin. The content ratio of the thermoplastic resin is less than 50% by weight, preferably less than 30% by weight, based on the total of 100% by weight of the polycarbonate resin and the thermoplastic resin.

  Examples of the thermoplastic resin include polystyrene, methyl methacrylate-styrene copolymer, acrylonitrile-styrene copolymer, polyvinyl alcohol, polyethylene terephthalate, polyethylene naphthalate, polypropylene, polyethylene, and the like. Two or more kinds can also be used.

  As the acrylic resin, for example, a methacrylic resin is used. The methacrylic resin is a polymer mainly composed of a methacrylic acid ester, and may be a homopolymer of a methacrylic acid ester, or a methacrylic acid ester of 50% by weight or more and other monomers of 50% by weight or less. A copolymer may also be used. Here, as the methacrylic acid ester, an alkyl ester of methacrylic acid is usually used.

  The preferred monomer composition of the methacrylic resin is 50 to 100% by weight of alkyl methacrylate, 0 to 50% by weight of alkyl acrylate, and 0 to 49% by weight of other monomers based on all monomers. More preferably, the alkyl methacrylate is 50 to 99.9% by weight, the alkyl acrylate is 0.1 to 50% by weight, and other monomers are 0 to 49% by weight.

  Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and the like, and the alkyl group usually has 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. Of these, methyl methacrylate is preferably used.

  Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. The alkyl group usually has 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms.

The monomer other than alkyl methacrylate and alkyl acrylate may be, for example, a monofunctional monomer, that is, a compound having one polymerizable carbon-carbon double bond in the molecule, or polyfunctional. Although it may be a monomer, that is, a compound having at least two polymerizable carbon-carbon double bonds in the molecule, a monofunctional monomer is preferably used.
Examples of the monofunctional monomer include styrene monomers such as styrene, α-methylstyrene, and vinyl toluene, alkenyl cyanide such as acrylonitrile and methacrylonitrile, acrylic acid, methacrylic acid, maleic anhydride, N -Substituted maleimide and the like.
Examples of polyfunctional monomers include polyunsaturated carboxylic acid esters of polyhydric alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, trimethylolpropane triacrylate, allyl acrylate, allyl methacrylate, and cinnamon. Alkenyl esters of unsaturated carboxylic acids such as allyl acid, polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, aromatic polyalkenyl compounds such as divinylbenzene, etc. Can be mentioned.

  In addition, as for said alkyl methacrylate, alkyl acrylate, and monomers other than these, respectively, you may use those 2 or more types as needed.

  From the viewpoint of heat resistance, the methacrylic resin preferably has a glass transition temperature of 70 ° C. or higher, more preferably 80 ° C. or higher, and further preferably 90 ° C. or higher. This glass transition temperature can be appropriately set by adjusting the type of monomer and the ratio thereof.

  The methacrylic resin can be prepared by polymerizing the monomer component by a method such as suspension polymerization, emulsion polymerization, or bulk polymerization. At that time, it is preferable to use an appropriate chain transfer agent at the time of polymerization in order to obtain a suitable glass transition temperature or to obtain a melt viscosity showing a moldability to a suitable resin plate. What is necessary is just to determine the addition amount of a chain transfer agent suitably according to the kind of monomer, its ratio, etc.

A thermoplastic resin other than the acrylic resin may be mixed with the acrylic resin. The content ratio of the thermoplastic resin is less than 50% by weight, preferably less than 30% by weight, based on 100% by weight of the total of the acrylic resin and the thermoplastic resin.
As a thermoplastic resin, the thing similar to what was illustrated as a thermoplastic resin which can be mixed with the above-mentioned polycarbonate resin is mentioned, Those 2 or more types can also be used as needed.

  Rubber particles may be added to the acrylic resin. By adding rubber particles to the acrylic resin, the impact resistance of the laminate obtained by melt coextrusion molding of the acrylic resin and the polycarbonate resin can be improved. Here, as the rubber particles, for example, acrylic rubber particles, butadiene rubber particles, styrene-butadiene rubber particles, and the like can be used, and among them, acrylic rubber from the viewpoint of weather resistance and durability. Particles are preferably used.

  The acrylic rubber particles preferably have an elastic polymer layer of about 20 to 60% by weight, preferably have a hard layer as the outermost layer, and further have a hard layer as the innermost layer. It may be a thing.

  The elastic polymer layer may be 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. One or more monofunctional monomers selected from the group consisting of acrylate, acrylamide, hydroxy lower alkyl acrylate, hydroxy lower alkyl methacrylate, acrylic acid and methacrylic acid are crosslinked with a polyfunctional monomer such as allyl methacrylate. It may be a polymer layer.

  Examples of the lower alkyl group in the lower alkyl acrylate include linear or branched alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl and hexyl groups, Examples of the lower alkoxy group in the lower alkoxyalkyl acrylate include linear or branched alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy, pentyloxy, and hexyloxy groups. Can be mentioned. In the case where the monofunctional monomer is used as a main component to form a copolymer, other monofunctional monomers such as styrene and substituted styrene may be copolymerized as a copolymerization component.

  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 is good to be. Examples of the alkyl group having 1 to 4 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and t-butyl.

  When the main component is an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, the copolymer component includes other alkyl methacrylates, alkyl acrylates, styrene, substituted styrenes, acrylonitrile, methacrylonitrile, etc. A monofunctional monomer 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 the alkyl methacrylate include the same linear or branched alkyl groups having 1 to 6 carbon atoms as exemplified for the lower alkyl group described above.

  The above acrylic rubber particles are described in, for example, Japanese Patent Publication No. 55-27576, Japanese Patent Laid-Open No. 6-80739, Japanese Patent Laid-Open No. 49-23292, and the like.

  The content ratio of the acrylic rubber particles is preferably 3 to 20% by weight, more preferably 5 to 15% by weight, based on the total of 100% by weight of the acrylic resin and the acrylic rubber particles. If the content of acrylic rubber particles is too small, it is difficult to improve the impact resistance of the laminate, and if the content of acrylic rubber particles is too large, the surface hardness of the laminate tends to decrease, which is not preferable.

  For polycarbonate resin and acrylic resin, if necessary, for example, light diffusing agent, matting agent, ultraviolet absorber, surfactant, impact resistance, polymer antistatic agent, antioxidant, flame retardant, lubricant , Dyes, pigments and the like may be added.

The laminate of the present invention has a cross section perpendicular to the extrusion direction, and the distance (L) from one surface of the polycarbonate resin layer in the thickness direction is the X axis, and the light with a wavelength of 546 nm at the distance (L). The difference (ΔN) between the birefringence index (N ₀ ) and the birefringence index (N ₁ ) with respect to light having a wavelength of 546 nm at the distance (L) after the resin plate is heated at 80 ° C. for 1 hour is expressed as the Y-axis. The absolute value (a) of the slope value in the linear expression of X and Y calculated by the least square method is 0.3 or less, preferably 0.2 or less, more preferably 0.1 or less. is there. Moreover, as a lower limit of this absolute value (a), Preferably it is 0 or more, More preferably, it is 0.01 or more, More preferably, it is 0.03 or more. When the absolute value (a) is in the predetermined range, warpage deformation of the laminated board in a high temperature environment is suppressed. The reason for this is presumed as follows.

  That is, when a laminate is subjected to extrusion molding, a residual stress is generated inside the laminate, and if the residual stress is anisotropic, the residual stress is reduced when the laminate is exposed to a high temperature environment. Accordingly, warpage deformation occurs in the laminate. For this reason, the amount of warp deformation increases as the residual stress of the laminate varies greatly with the distance (L) in the thickness direction. The birefringence of the laminate is the sum of the component due to molecular orientation and the component due to stress. When the residual stress is relaxed, the birefringence is reduced by the reduced stress. Becomes smaller. Therefore, if the amount of change in birefringence before and after heating does not vary greatly in the thickness direction, that is, if the absolute value (a) of the inclination value is within the predetermined range, warping deformation is suppressed. It is guessed.

  The distance (L) is a distance from one surface of the polycarbonate resin layer in the thickness direction in a cross section perpendicular to the extrusion direction, and the laminate is cut in a direction (width direction) perpendicular to the extrusion direction, What is necessary is just to measure the distance from one surface across the other surface from the one surface of the polycarbonate resin layer in the obtained cut surface. The minimum value of the distance (L) is 0, and the position where the distance (L) is the minimum value is one surface of the polycarbonate resin layer. The maximum value of the distance (L) corresponds to the thickness of the laminate, and the position where the distance (L) is the maximum value is the other surface of the polycarbonate resin layer. Here, one surface of the polycarbonate resin layer may be any surface of both surfaces of the polycarbonate resin layer. However, in the case where the laminated plate has a two-layer structure described later, the laminated plate is melt-extruded. It is preferable that it is the polycarbonate resin layer surface which contacted the 1st cooling roll, and when a laminated board is a 3 layer structure mentioned later, it is the polycarbonate resin layer surface which contact | connects the acrylic resin layer which contacted the 1st cooling roll. Preferably there is.

The birefringence (N ₀ ) and the birefringence (N ₁ ) are respectively the birefringence at the distance (L) and the distance (L) after heating the laminated plate at 80 ° C. for 1 hour. It is a birefringence, and before and after heating the laminated plate, a cross section perpendicular to the extrusion direction is cut out, and this cut surface is light having a wavelength of 546 nm using a micro birefringence imaging system Abrio (manufactured by Tokyo Instruments Inc.). And the birefringence at the distance (L) may be measured.
The difference between the birefringence (N ₀ ) and the birefringence (N ₁ ) measured in this way is ΔN.

  In order to set the absolute value (a) within a predetermined range, for example, as will be described later, the peripheral speed (V2) of the cooling roll immediately before the final cooling roll and the peripheral speed (V3) of the final cooling roll When the molten resin extruded from the die is wound around the cooling roll immediately before the final cooling roll, the peripheral speed ratio (V3 / V2) of What is necessary is just to heat the surface which is not contacting this cooling roll.

  The laminate is usually in the form of a sheet or film, and the thickness is usually 0.4 to 2.0 mm, preferably 0.5 to 1.5 mm. The laminate may be provided with an acrylic resin layer on at least one surface of the polycarbonate resin layer, and may have a two-layer structure including an acrylic resin layer on one surface of the polycarbonate resin layer, or both surfaces of the polycarbonate resin layer. Although a three-layer structure including an acrylic resin layer may be used, a three-layer structure is preferable from the viewpoint of difficulty in warping in a high-temperature environment or a high-humidity environment. In the case of a three-layer configuration, the acrylic resin layer provided on one surface of the polycarbonate resin layer and the acrylic resin layer provided on the other surface of the polycarbonate resin layer may be the same or different in composition and thickness. It may be.

  The laminated board of the present invention thus obtained is widely used for lighting covers and signboards, building materials and electrical products, optical applications such as mobile phones and liquid crystal televisions, because warpage deformation under high temperature environments is suppressed. In particular, it can be used as a light guide plate, a touch panel substrate, or a display protection plate as an optical application, and is particularly preferably used as a light guide plate or a touch panel substrate. Applications of touch panels and liquid crystal displays include, for example, display windows of portable information terminals such as televisions, computer monitors, mobile phones, PHS (Personal Handy-phone System), PDA (Personal Digital Assistant), digital cameras, and handy-type video. Examples include a camera finder and a display window of a portable game machine.

  In order to produce a light guide plate from the laminate of the present invention, the laminate may be cut into a required size. In order to produce a touch panel substrate or a display protection plate, first, if necessary, processing such as printing and drilling is performed on the extruded plate, and then the extruded plate is cut into a required size. Then, if a laminated board is set to a display, it can be used conveniently as a touchscreen board | substrate or a display protection board.

  The laminate may be a scratch-resistant laminate by forming a cured film on at least one surface of the laminate. When forming a cured film on both sides of the laminate, the composition and thickness of the cured film on both sides may be the same or different.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  The scratch-resistant laminate thus obtained can be used for various applications because warpage deformation under a high temperature environment is suppressed and has excellent impact resistance and surface hardness, but is particularly preferably used as a display protective plate. In particular, it is more preferably used as a touch panel display protective plate. Examples of the type of display to be protected include a CRT display, a liquid crystal display, a plasma display, and an EL display. In addition, the applications of the protected display include, for example, a display window of a portable information terminal such as a TV or a computer, a mobile phone, a PHS, or a PDA, a finder portion of a digital camera or a handheld video camera, a portable game machine A display window etc. are mentioned. The scratch-resistant resin plate of the present invention is preferably used as a display window protective plate for portable information terminals such as liquid crystal displays and EL displays.

  In order to produce a display protective plate from the scratch-resistant laminate of the present invention, first, if necessary, processing such as printing, drilling and the like may be performed, and cutting to a required size may be performed. Then, if it is set on the display, the display can be effectively protected. At that time, in the case of an abrasion-resistant laminated board in which a cured film is formed on one surface of the laminated board, it is preferable that the cured film is placed on the front side (viewer side).

  The laminate of the present invention is produced by melt extrusion molding so that an acrylic resin layer is provided on at least one surface of the polycarbonate resin layer. Hereinafter, an embodiment of a method for producing a laminated board according to the present invention will be described in detail with reference to FIG.

  FIG. 1 is a schematic explanatory view showing a method for producing a laminated board according to an embodiment of the present invention. As shown in FIG. 1, the polycarbonate resin is put into the extruder 1A, and the acrylic resin is put into the extruder 1B to perform melt kneading. In FIG. 1, two extruders are used, but the number of extruders may be three or more, and may be appropriately changed depending on the number of laminated resin layers and the type of resin used.

  The melt-kneaded polycarbonate resin and acrylic resin are respectively supplied to the feed block 2 and have a two-layer configuration in which an acrylic resin layer is provided on one surface of the polycarbonate resin layer, or an acrylic resin layer is provided on both surfaces of the polycarbonate resin layer. After being melt-laminated and integrated so as to have a three-layer structure, it is extruded from the die 3 as a plate-shaped molten resin 4.

  Examples of the extruders 1A and 1B include a single screw extruder and a twin screw extruder. In FIG. 1, the feed block and the T die are used in combination, but a multi-manifold die may be used.

  The molten resin 4 extruded from the die 3 is molded and cooled by the cooling unit 5. The cooling unit 5 includes at least three cooling rolls 51, 52, 53.

  The molten resin 4 is sandwiched between the first cooling roll 51 and the second cooling roll 52 and wound around the second cooling roll 52, and further between the second cooling roll 52 and the third cooling roll 53. The laminated plate 6 is obtained by being sandwiched and molded and cooled. When the laminated plate 6 is wound around the second cooling roll 52, the surface not in contact with the cooling roll 52 may be heated by a heater (not shown). Thus, the warp deformation in the high temperature environment of a laminated board can be suppressed by heating with a heater.

  When the molten resin 4 has a two-layer configuration in which an acrylic resin layer is provided on one surface of the polycarbonate resin layer, the molten resin 4 is placed in the first position so that the polycarbonate resin layer surface of the molten resin 4 is in contact with the first cooling roll 51. It is preferable to sandwich the first cooling roll 51 and the second cooling roll 52.

  As for the 1st-3rd cooling rolls 51-53, at least 1 roll is connected to rotation drive means, such as a motor, and it is constituted so that each roll may rotate with predetermined peripheral speed.

  The peripheral speed ratio (V3 / V2) between the peripheral speed (V2) of the second cooling roll 52 and the peripheral speed (V3) of the third cooling roll 53 is preferably greater than 1, and is not less than 1.001. Is more preferable. Thus, the curvature deformation in the high temperature environment of the laminated board 6 can be suppressed by making a peripheral speed ratio (V3 / V2) into a predetermined range.

  The upper limit value of the peripheral speed ratio (V3 / V2) is not particularly limited as long as the molten resin 4 can be taken and the effects of the present invention are exhibited, but it is preferably 1.100 or less. It is more preferably 050 or less, still more preferably 1.010 or less, and particularly preferably 1.006 or less.

  The peripheral speeds (V1) to (V3) of the first to third cooling rolls 51 to 53 are usually 0.5 to 6 m / sec, preferably 1 to 5 m / sec, and preferably 2 to 4 m / sec. It is more preferable to set the second, and it is preferable that the peripheral speed ratio (V3 / V2) be greater than 1 within this numerical range.

  It does not specifically limit as the 1st-3rd cooling rolls 51-53, The normal cooling roll currently used by the conventional extrusion molding is employable. Specific examples include a drilled roll, a spiral roll, a metal elastic roll, and a rubber roll. The surface state of the first to third cooling rolls 51 to 53 may be, for example, a mirror surface or may have a pattern or unevenness.

  As the elastic roll, for example, a substantially cylindrical shaft roll, a cylindrical metal thin film disposed so as to cover the outer peripheral surface of the shaft roll, and sealed between the shaft roll and the metal thin film And an elastic roll (A) configured to be temperature-controllable by controlling the temperature of the fluid, and an elastic material in which a metal thin film is wound around the outer peripheral surface of a substantially cylindrical rubber roll. A roll (B) etc. are mentioned. The metal thin film in these elastic rolls (A) and (B) is made of, for example, stainless steel, and the thickness is preferably about 0.2 to 3 mm.

  The 1st-3rd cooling rolls 51-53 may be comprised by 1 type chosen from a metal roll and an elastic roll, and may be comprised combining a metal roll and an elastic roll. When the first to third cooling rolls 51 to 53 are configured by combining a metal roll and an elastic roll, a laminated sheet with reduced strength, anisotropy of heat shrinkage, and the like can be obtained.

  That is, when the molten resin 4 is sandwiched between the metal roll and the elastic roll, the elastic roll is elastically deformed into a concave shape along the outer peripheral surface of the metal roll via the molten resin 4, and the elastic roll and the metal roll are melted into the molten resin. 4 to contact with a predetermined contact length. As a result, the metal roll and the elastic roll come into pressure contact with the molten resin 4 by surface contact, and the molten resin 4 sandwiched between these rolls is formed while being uniformly pressed into a planar shape. As a result, it is possible to obtain the laminate 6 with reduced distortion during film formation and reduced strength and thermal shrinkage anisotropy.

  When combining a metal roll and an elastic roll, it is preferable that the 1st cooling roll 51 is comprised with an elastic roll, and the 2nd, 3rd cooling rolls 52 and 53 are comprised with a metal roll. Moreover, it is preferable that the said elastic roll which comprises the 1st cooling roll 51 is an elastic roll (A). Thereby, the effect acquired by combining a metal roll and an elastic roll can be heightened.

  The number of cooling rolls is not limited to three. For example, in the case of using four cooling rolls, the molten resin extruded from the die is supplied between the first cooling roll and the second cooling roll, the lower part of the second cooling roll is made about a half turn, and the second Supplied between the cooling roll and the third cooling roll. Next, the molten resin is supplied between the third cooling roll and the fourth cooling roll, about half of the upper part of the third cooling roll.

  The laminate 6 obtained by being wound around the third cooling roll 53 is further taken up by a take-up roll (not shown). At least one surface of the laminated plate 6 may be heated by a heater (not shown) between the third cooling roll 53 and the take-up roll. Thus, the warp deformation in the high temperature environment of a laminated board can be suppressed by heating with a heater.

  A heater will not be specifically limited if the laminated board 6 can be heated, For example, a far-infrared heater, a hot air heater (hot air generator), etc. are mentioned. The heating is preferably performed at a temperature equal to or higher than the heat deformation temperature (Th) of the polycarbonate resin and the acrylic resin constituting the laminated plate 6, more preferably in the range of Th to (Th + 50 ° C.), and (Th + 5 ° C.) to (Th + 30). More preferably, it is carried out in the range of ° C. Moreover, the time to heat is not specifically limited, Preferably it is 1-500 second, More preferably, it is 5-300 second. The heating time refers to the time from when a certain point on the surface of the laminate 5 starts to be heated by the heater until the point goes out of the heater and is not heated.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to these Examples.

The configuration of the extrusion apparatus used in the examples and comparative examples is as follows.
Extruder 1A: Screw diameter 65 mm, single screw, vented extruder (manufactured by Hitachi Zosen).
Extruder 1B: Screw diameter 45 mm, single screw, vented extruder (manufactured by Hitachi Zosen Corporation).
Feed block 2: Feed block of 2 types and 3 layers (manufactured by Hitachi Zosen Corporation).
Die 3: T die (resin discharge port width 1400 mm, lip interval 1 mm (manufactured by Hitachi Zosen)).
Cooling unit 5: Horizontal type, first to third cooling rolls 51 to 53 having a diameter of 250 mm were used. These first to third cooling rolls 51 to 53 were connected to a motor and configured to rotate independently at a predetermined peripheral speed. The configurations of the first to third cooling rolls 51 to 53 other than those described above are as follows.

1st cooling roll 51: The elastic roll mentioned later was used.
Second and third cooling rolls 52 and 53: Stainless steel spiral rolls were used.

The elastic roll used in the first cooling roll 51 was an elastic roll in which a metal thin film was disposed so as to cover the outer peripheral surface of the shaft roll, and a fluid was sealed between the shaft roll and the metal thin film.
The shaft roll, metal thin film and fluid are as follows.

Axial roll: stainless steel one was used.
Metal thin film: A 2 mm thick stainless steel mirror metal sleeve was used.
Fluid: Oil was used. The temperature of this oil was controlled so that the temperature of the elastic roll could 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.

In the following Examples and Comparative Examples, the following polycarbonate resin, methacrylic resin and acrylic rubber particles were used.
Polycarbonate resin: “Caliber 301-10” (thermal deformation temperature: 140 ° C.) manufactured by Sumitomo Dow Co., Ltd. was used.
Methacrylic resin: Pellets of thermoplastic polymer (thermal deformation temperature: 104 ° C.) obtained by bulk polymerization of monomers consisting of 97.8% methyl methacrylate and 2.2% methyl acrylate were used. This 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: 1987.
Acrylic rubber particles: The innermost layer is a hard polymer obtained by polymerization of monomers consisting of 93.8% methyl methacrylate, 6.0% methyl acrylate, and 0.2% allyl methacrylate. The intermediate layer is an elastic polymer obtained by polymerization of a monomer composed of 81% butyl acrylate, 17% styrene and 2% allyl methacrylate, and the outermost layer is 94% methyl methacrylate and methyl acrylate. A hard polymer obtained by polymerization of a monomer comprising 6%, and the weight ratio of innermost layer / intermediate layer / outermost layer is 35/45/20, and the average of the elastic polymer layers of the intermediate layer Spherical three-layer rubber particles obtained by an emulsion polymerization method having a particle diameter of 0.22 μm were used. The average particle diameter of the rubber particles is that the rubber particles are mixed with a methacrylic resin to form a film, and the elastic polymer (intermediate layer) is dyed with ruthenium oxide in the cross section, and observed with an electron microscope. I asked for it.

Example 1
First, as a material for forming the acrylic resin layer, methacrylic resin and acrylic rubber particles are supermixed so that the acrylic rubber particles are 6% by weight based on the total of 100% by weight of the methacrylic resin and acrylic rubber particles. And melt-kneading with a twin screw extruder to obtain a methacrylic resin composition comprising methacrylic resin and acrylic rubber particles as pellets.

  Next, the extruder 1A, the extruder 1B, the feed block 2, the die 3, and the first to third cooling rolls 51 to 53 were arranged as shown in FIG. Here, the second and third cooling rolls 52 and 53 were rotated at the peripheral speeds V2 and V3 shown in Table 1.

  Furthermore, the polycarbonate resin was melt-kneaded with the extruder 1A and the methacrylic resin composition with the extruder 1B, and these were supplied to the feed block 2. These were provided with an acrylic resin layer on both sides of the polycarbonate resin layer through the feed block 2, and a film-like molten resin 4 was extruded from the die 3. The extruded molten resin 4 is sandwiched between the first cooling roll 51 and the second cooling roll 52 and then wound around the second cooling roll 52 between the second cooling roll 52 and the third cooling roll 53. A three-layer structure having a total thickness of 1.00 mm, which is sandwiched and further wound around a third cooling roll 53 and cooled, and is provided with an acrylic resin layer having a thickness of 0.07 mm on both sides of a polycarbonate resin layer having a thickness of 0.86 mm. Laminated plate 6 was obtained.

(Example 2)
The second and third cooling rolls 52 and 53 are rotated at the peripheral speeds V2 and V3 shown in Table 1, and further, a heater (a far-red panel heater manufactured by Hitachi Zosen Corp.) in the vertically downward direction of the second cooling roll 52. Example 1 except that the lower surface of the molten resin 4 wound around the second cooling roll 52 (non-contact surface with the second cooling roll 52) was heated with the heater at 300 ° C. for 10 seconds. The same operation was performed to obtain a laminate 6 having a total thickness of 1.00 mm and an acrylic resin layer having a thickness of 0.07 mm on both sides of a polycarbonate resin layer having a thickness of 0.86 mm.

(Example 3)
The second and third cooling rolls 52 and 53 are rotated at the peripheral speeds V2 and V3 shown in Table 1. Furthermore, instead of the feed block of the 2 types and 3 layers distribution, the feed block of 2 types and 2 layers distribution (Hitachi Zosen ( And an acrylic resin layer supplied from the extruder 1B to the feed block is provided on one surface of the polycarbonate resin layer supplied from the extruder 1A to the feed block via the feed block. 3 except that the polycarbonate resin layer surface is in contact with the first cooling roll 51 when the film-like molten resin 4 extruded from 3 is sandwiched between the first cooling roll 51 and the second cooling roll 52. 2 and having a total thickness of 1.00 mm including an acrylic resin layer having a thickness of 0.07 mm on one surface of a polycarbonate resin layer having a thickness of 0.93 mm To obtain a laminated plate 6 adult.

(Comparative Example 1)
Except that the second and third cooling rolls 52 and 53 were rotated at the peripheral speeds V2 and V3 shown in Table 1, the same operation as in Example 1 was performed, and both of the polycarbonate resin layers having a thickness of 0.86 mm were performed. A laminate 6 having a three-layer structure having a total thickness of 1.00 mm and an acrylic resin layer having a thickness of 0.07 mm on the surface was obtained.

(Comparative Example 2)
The second and third cooling rolls 52 and 53 are rotated at the peripheral speeds V2 and V3 shown in Table 1, and further, a heater (a far-red panel heater manufactured by Hitachi Zosen Corporation) is installed in the vertically upward direction of the third cooling roll 53. 1), and the upper surface of the molten resin 4 wound around the third cooling roll 53 (non-contact surface with the third cooling roll 53) was heated with the heater at 300 ° C. for 10 seconds. The same operation was performed to obtain a laminate 6 having a total thickness of 1.00 mm and an acrylic resin layer having a thickness of 0.07 mm on both sides of a polycarbonate resin layer having a thickness of 0.86 mm.

<Evaluation>
About each obtained laminated board (Examples 1-3 and Comparative Examples 1 and 2), evaluation of the absolute value (a) and evaluation of the curvature deformation in a high temperature environment were performed. The evaluation method is shown below, and the results are shown in Table 1.

(Evaluation method of absolute value (a))
First, from the laminate, the length in the width direction is 6 mm so that the center position in the direction (width direction) perpendicular to the extrusion direction in the laminate is the center, the length in the extrusion direction is 100 μm, A test piece was cut out with a length in the thickness direction of 1 mm. Next, with respect to one cut surface of the test piece, using a microbirefringence imaging system Abrio (manufactured by Tokyo Instruments Co., Ltd.), light having a wavelength of 546 nm is incident from the cut surface, and at the center position in the width direction. The birefringence (N0) at a distance (L) from one surface of the polycarbonate resin layer in the thickness direction was measured. Here, when the laminated plate has a two-layer structure, one surface of the polycarbonate resin layer is a polycarbonate resin layer surface that is in contact with the first cooling roll when the laminated plate is formed by melt extrusion. In the case of the layer configuration, the polycarbonate resin layer surface was in contact with the acrylic resin layer in contact with the first cooling roll. Furthermore, after heating this laminated board at 80 degreeC for 1 hour, the test piece was cut out similarly and the birefringence (N1) in distance (L) was measured similarly. Then, the distance (L) is plotted on the X axis, and the difference (ΔN) between the birefringence index (N0) and the birefringence index (N1) at the distance (L) is plotted on the Y axis, and calculated by the least square method. The absolute value of the slope value in the linear expression of X and Y was calculated as the absolute value (a).

(Evaluation method of warpage deformation)
First, a test piece was cut out from the laminate. The shape of the test piece was 85 mm in the extrusion direction and 55 mm in the direction (width direction) orthogonal to the extrusion direction. Place this test piece on a surface plate with the convex warped side facing down, measure the amount of lifting at the four corners with a position sensor (manufactured by Keyence Corporation), and average the measured values. Was the initial warpage amount.

  Next, the test piece was installed in a thermostat set at a temperature of 120 ° C. in a state where the test piece was suspended so that the extrusion direction was vertical, and held for 1 hour. Thereafter, the amount of lifting at the four corners of the test piece was measured in the same manner as the initial warpage amount, and the heating warpage amount was obtained. The initial warpage amount and the heating warpage amount were applied to the formula: heating warpage amount−initial warpage amount, and the warpage shift amount was calculated.

1A, 1B Extruder 2 Feed block 3 Die 4 Molten resin 5 Cooling unit 51 First cooling roll (cooling roll two before the final cooling roll)
52 2nd cooling roll (cooling roll immediately before the final cooling roll)
53 Third cooling roll (final cooling roll)
6 laminates

Claims (4)

A laminate comprising a polycarbonate resin and an acrylic resin melt-extruded and provided with a layer made of acrylic resin on at least one surface of the layer made of polycarbonate resin,
The birefringence (N ₀ ) for light having a wavelength of 546 nm at the distance (L) with the X axis as the distance (L) from one surface of the polycarbonate resin layer in the thickness direction in a cross section perpendicular to the extrusion direction And the difference (ΔN) between the birefringence index (N ₁ ) for light having a wavelength of 546 nm at the distance (L) after heating the laminated plate at 80 ° C. for 1 hour, is plotted on the Y axis, and the least square method An absolute value of an inclination value in a linear expression of X and Y calculated by the above is 0.3 or less.   The laminated board according to claim 1 whose thickness is 0.4-2.0 mm.   A scratch-resistant laminate comprising a cured film formed on at least one surface of the laminate according to claim 1.   A protective plate for a display comprising the laminated plate according to claim 1.

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