JP2009051137A - Light diffusive polycarbonate resin board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly light diffusible polycarbonate resin board having excellent initial tinting, light fastness, mechanical strength, light diffusion, and brightness without damaging transparency of a polycarbonate resin, which can be used to applications requiring high degree of optical properties, particularly preferably used in a light diffusion board used in a back light for a liquid crystal display device, etc. <P>SOLUTION: The light diffusible polycarbonate resin board is formed by co-extruding a surface layer comprising a polycarbonate resin composition containing a specified UV-ray absorber as the essential ingredient on at least one surface of a substrate material comprising a polycarbonate resin composition containing a light diffusing agent consisting of specified silicone rubber particles as the essential ingredient and optionally polycaprolactone. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides light diffusion by coextruding a polycarbonate resin layer containing a UV absorber having a specific structure as a surface layer onto a substrate made of a polycarbonate resin containing a specific light diffusing agent and optionally polycaprolactone. The present invention relates to a light diffusing polycarbonate resin plate having improved properties, brightness, mechanical strength, initial colorability and light resistance.

  Polycarbonate resins are used in a wide range of applications as resins having high light transmittance. For example, it is also used in large quantities in the construction field of sky domes, top lights, arcades, condominium waistboards, and road sideboards. Many of these uses are milky white light diffusing plates. A method of mixing a polycarbonate resin with a light diffusing agent such as calcium carbonate, barium sulfate, silicon oxide, titanium oxide (Patent Document 1), a method of dispersing fine particles (patent) Document 2) has been proposed.

  Such light diffusing polycarbonate resin plates are used in edge light type or direct backlight type surface light source bodies for liquid crystal displays and surface light source bodies for scanners, and require high light diffusibility and brightness. ing.

  The applicant of the present invention has proposed a composition (Patent Document 3) in which a light diffusing agent and polycaprolactone are blended with a transparent thermoplastic resin in order to obtain higher light diffusibility and brightness.

  On the other hand, although polycarbonate resin is excellent in light resistance, in the case of a light diffusing polycarbonate resin plate, since it is used in a surface light source body as described above, there is a problem of discoloration caused by exposure to light rays such as a cold cathode tube as a light source. Therefore, further improvement in light resistance has been demanded.

  For the purpose of imparting light resistance to a polycarbonate resin, methods for imparting light resistance using various ultraviolet absorbers (Patent Documents 4 and 5) have been studied. However, the molding temperature of the polycarbonate resin is relatively high at 240 to 380 ° C., and the thermal decomposition temperature is low in the conventional ultraviolet absorber, and therefore, part of the ultraviolet absorber is evaporated during the molding process. There were problems such as yellowing of the hue and poor appearance.

  Furthermore, the light diffusing plate is not only excellent in light diffusibility and brightness, but particularly in a light diffusing plate for a direct type backlight unit of a large-sized liquid crystal television, light is required due to demands for thinning of the unit itself and cost reduction. There is a need to reduce the thickness of the diffusion plate, and there has been a demand for a light diffusion plate having mechanical strength that can withstand that.

Japanese Patent Publication No.57-24186 Japanese Patent Laid-Open No. 05-257002 Japanese Patent Publication No.57-24186 JP 2002-105271 A JP 2005-3959 A

    The present invention provides a light diffusing polycarbonate resin plate that not only provides high light diffusibility and brightness when incorporated in a surface light source body, but also has excellent initial colorability, light resistance and mechanical strength. With the goal.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an ultraviolet absorber having a specific structure is formed on at least one surface of a base material comprising a specific light diffusing agent and, if desired, a polycarbonate resin containing polycaprolactone. It was found that a light-diffusing polycarbonate resin plate having excellent initial colorability, light resistance, and mechanical strength was obtained by coextrusion molding using a polycarbonate resin layer containing a surface layer, and the present invention was completed.

That is, the present invention provides a surface layer comprising a polycarbonate resin composition containing an ultraviolet absorber as an essential component on at least one side of a substrate comprising a polycarbonate resin composition containing a light diffusing agent and optionally polycaprolactone as an essential component. In a light diffusing polycarbonate resin plate formed by coextrusion molding,
The light diffusing agent is a silicone rubber particle having a skeleton composed of a bifunctional siloxane unit and a trifunctional siloxane unit and an alkyl group on the surface, and an average particle diameter of 0.5 to 10 μm, and The content of the light diffusing agent is 0.1 to 1.5 parts by weight per 100 parts by weight of the polycarbonate resin used for the substrate, and the ultraviolet absorber is represented by the following general formula (1) The content of the ultraviolet absorber is 0.01 to 0.8 parts by weight per 100 parts by weight of the polycarbonate resin used for the surface layer,
The present invention provides a light diffusing polycarbonate resin plate.
General formula (1)

（一般式（１）において、Ｒ１は炭素数１〜１２のアルキル基、Ｒ２は炭素数１〜１２のアルコキシ基を表す。）

(In General Formula (1), R1 represents an alkyl group having 1 to 12 carbon atoms, and R2 represents an alkoxy group having 1 to 12 carbon atoms.)

  The light diffusing polycarbonate resin plate of the present invention has excellent initial colorability, light resistance, mechanical strength, light diffusibility, and luminance without impairing the transparency of the polycarbonate resin. Therefore, it is suitably used for a light diffusing plate used for an application requiring high optical performance, in particular, a backlight for a liquid crystal display device, and the practical utility value is extremely high.

  The polycarbonate resin used for the substrate and the surface layer of the present invention can be obtained by a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate are reacted. A typical example of the polymer is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).

  Examples of the dihydroxydiaryl compound include bisphenol 4-, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2, 2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3) -Tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 ' Dihydroxy diaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxy diary such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone Sulfone, and the like. These are used individually or in mixture of 2 or more types. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be mixed and used.

Furthermore, the above dihydroxyaryl compound and a trivalent or higher phenol compound as shown below may be used in combination. Trihydric or higher phenols include phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptene, 2,4,6-dimethyl-2,4,6-tri- (4 -Hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -ethane and 2,2-bis- [4 4- (4,4'-dihydroxydiphenyl) -cyclohexyl] -propane and the like.

  The viscosity average molecular weight of the polycarbonate resin used for the surface layer or the substrate is usually 10,000 to 100,000, preferably 15,000 to 35,000, and more preferably 17,000 to 28,000. In producing such a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as necessary.

The light diffusing agent used in the present invention comprises a skeleton of a bifunctional siloxane unit represented by the following general formula (3) and a trifunctional siloxane unit represented by the following general formula (4), and further an alkyl group is a particle. These are silicone rubber particles present on the surface.
General formula (3)

一般式（４）

General formula (4)

上記一般式（３）および一般式（４）において、Ｒ^１、Ｒ^２およびＲ^３はそれぞれ同一でも異なっていてもよいアルキル基を示す。

In the said General formula (3) and General formula (4), R < ¹ >, R < ² > and R < ³ > show the alkyl group which may be same or different, respectively.

  The ratio of the bifunctional siloxane unit in the skeleton constituting the silicone rubber particles of the present invention is preferably 30 to 95% by weight, more preferably 40 to 70% by weight. The larger the ratio of the bifunctional siloxane unit, the lower the glass transition temperature (Tg) of the silicone rubber and the lower the refractive index.

  Further, the trifunctional siloxane unit is preferably 5 to 70% by weight, more preferably 30 to 60% by weight of the siloxane unit constituting the silicone rubber particles. Trifunctional siloxane units are used to make silicone rubber a cross-linked structure, which can increase the refractive index.

The silicone rubber particles of the present invention can be made by a known method. First, as described in, for example, “Synthesis and Application of Organosilicon Polymer” (published by CMC Co., Ltd., November 30, 1989), the skeleton is co-hydrolyzed of bifunctional and trifunctional chlorosilanes or alkoxysilanes. There is a method by co-condensation. By selecting an alkyl group directly bonded to Si of chlorosilane or alkoxysilane used at this time, R ¹ , R ² and R ³ can be determined. Among these, an alkyl group having 1 to 6 carbon atoms, particularly a methyl group is preferable.

  What is necessary is just to select the quantity ratio of a bifunctional siloxane unit and a trifunctional siloxane unit with Tg of a desired silicone rubber particle, and a refractive index. In addition, −50 to −200 ° C. is suitable for the Tg of the silicone rubber particles. A refractive index of 1.39 to 1.46 is suitable.

  The average particle diameter of the silicone rubber particles of the present invention is 0.5 to 10 μm. When the average particle size is less than 0.5 μm, sufficient light diffusibility cannot be exhibited, which is not preferable. On the other hand, if it exceeds 10 μm, the transmitted light decreases, which is not preferable. Preferably, it is the range of 2-4 micrometers.

  Examples of such silicone rubber particles include “Trefill E-600” and “Trefill E-606” manufactured by Toray Dow Corning Silicone.

  The blending amount of the silicone rubber particles of the present invention is preferably 0.1 to 1.5 parts by weight per 100 parts by weight of the polycarbonate resin of the base material. If the blending amount is less than 0.1 parts by weight, a sufficient light diffusion effect cannot be obtained, which is not preferable. On the other hand, if the amount exceeds 1.5 parts by weight, the light transmittance may be impaired, and sufficient light diffusion performance and brightness may not be obtained. More preferably, it is in the range of 0.5 to 1.2 parts by weight.

The ultraviolet absorber used in the present invention is a compound represented by the following general formula (1).
General formula (1)

（一般式（１）において、Ｒ１は炭素数１〜１２のアルキル基、Ｒ２は炭素数１〜１２のアルコキシ基を表す。）

(In General Formula (1), R1 represents an alkyl group having 1 to 12 carbon atoms, and R2 represents an alkoxy group having 1 to 12 carbon atoms.)

As a specific example of the compound represented by the general formula (1), an aryl group substituted with an alkyl group and an aryl group substituted with an alkoxy group are symmetrically substituted with respect to two nitrogen atoms in the oxanilide skeleton. In particular, a compound represented by the following general formula (2) is preferably used.
General formula (2)

  The ultraviolet absorber is easily available as a commercial product, and examples include Sanduvor VSU manufactured by Clariant Japan.

  The compounding quantity of the ultraviolet absorber used by this invention is 0.01-0.8 weight part per 100 weight part of polycarbonate resin of a surface layer. A blending amount of less than 0.01 part by weight is not preferable because sufficient light resistance cannot be obtained. On the other hand, if it exceeds 0.8 parts by weight, the initial colorability is inferior. More preferably, it is the range of 0.1-0.6 weight part.

  The polycaprolactone used in the present invention is a polymer produced by ring-opening polymerization of ε-caprolactone in the presence of a catalyst, and a 2-oxepanone homopolymer is particularly preferably used. The polymer is easily available as a commercial product, and a tone polymer manufactured by Dow Chemical Company, CAPA manufactured by Solvay Company, and the like are used. The viscosity average molecular weight of polycaprolactone is preferably 10,000 to 100,000, more preferably 40,000 to 90,000.

  Further, polycaprolactone includes those modified by coexisting with ε-caprolactone in the presence of 1,4-butanediol or the like, and modified polycaprolactone substituted with an ether or ester group at the molecular end. .

  The compounding quantity of polycaprolactone is 0.1-7 weight part per 100 weight part of polycarbonate resin of a base material. If the blending amount is less than 0.1 parts by weight, the light diffusion effect cannot be obtained and sufficient luminance cannot be obtained, which is not preferable. On the other hand, if it exceeds 7 parts by weight, sufficient mechanical strength cannot be obtained, which is not preferable. A more preferable composition ratio is 0.3 to 5 parts by weight.

  In the light diffusing polycarbonate resin plate of the present invention, various known additives, polymers, etc. may be added to the base material and / or the surface layer as necessary depending on the performance required in addition to the light diffusing property. it can. For example, in order to suppress discoloration of the resin molded product when exposed to light for a long period of time, a hindered amine-based light-resistant stabilizer is used, and further, in order to obtain a vivid color tone, a benzoxazole-based fluorescent whitening agent and These may be added in combination.

  In the light diffusing polycarbonate resin plate of the present invention, known additives other than those described above, for example, phenol-based or phosphorus-based heat stabilizer [2,6-di-t-butyl-4-methylphenol, 2- (1- Methylcyclohexyl) -4,6-dimethylphenol, 4,4'-thiobis- (6-tert-butyl-3-methylphenol), 2,2-methylenebis- (4-ethyl-6-tert-methylphenol), n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, tris (2,4-di-t-butylphenyl) phosphite, 4,4′-biphenylenediphosphinic acid tetrakis (2,4-di-t-butylphenyl), etc.], lubricant [paraffin wax, n-butyl stearate, synthetic beeswax, natural beeswax, glycerin monoester Montanic acid wax, polyethylene wax, pentaerythritol tetrastearate, etc.], colorant [eg dye], filler [calcium carbonate, clay, silica, glass fiber, glass sphere, glass flake, carbon fiber, talc, mica, various whiskers Etc.], fluidity improvers, spreading agents [epoxidized soybean oil, liquid paraffin, etc.], and other thermoplastic resins and various impact modifiers (polybutadiene, polyacrylates, ethylene / propylene rubbers, etc.) Rubber reinforced resin obtained by graft polymerization of a compound such as methacrylic acid ester, styrene, acrylonitrile, etc.) may be added to the rubber as required.

Embodiments and order in the present invention are shown below.
Light diffusing agent, if necessary, polycaprolactone, and polycarbonate resin used for the substrate are weighed in an arbitrary amount and mixed together with a tumbler, ribbon blender, high-speed mixer, etc. A method of melt-kneading and pelletizing using an extruder, or a method of measuring each component separately, putting them into the extruder from a plurality of feeders and melt-mixing them, and light diffusion to polycarbonate resin The agent can be blended at a high concentration, once melt-mixed and pelletized into a master batch, and then the master batch and the polycarbonate resin can be mixed at a desired ratio.
Then, when these components are melt-mixed, arbitrary conditions such as a position to be introduced into the extruder, an extrusion temperature, a screw rotation speed, a supply amount, and the like can be selected and pelletized. Thereby, the pellet for base materials is obtained.
Moreover, the ultraviolet absorber and the polycarbonate resin used for the surface layer can be weighed at an arbitrary blending amount, and a pellet for the surface layer can be obtained using the same method as described above.
The resulting pellets for the substrate and surface layer are melted and kneaded with 2 to 3 uniaxial or biaxial extruders respectively, and then supplied to the substrate feed block and the surface layer feed block of the coextrusion die, respectively. And a laminated sheet is obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. Unless otherwise specified, “%” and “parts” in the examples are based on weight.

The raw materials used are as follows.
Polycarbonate resin:
Caliber 200-13 manufactured by Sumitomo Dow
(Viscosity average molecular weight: 21500, hereinafter abbreviated as PC)
CAPA6500C manufactured by Polycaprolactone Solvay
(Viscosity average molecular weight: 50000, hereinafter abbreviated as PCL)
Silicone rubber particles:
TORAYFIL E-606 made by Toray Dow Corning Silicone
(Dimethylpolysiloxane, average particle diameter of 3 μm, hereinafter abbreviated as LD-1)
TORAYFIL E-601 made by Toray Dow Corning Silicone
(Epoxy-modified dimethylpolysiloxane, average particle size 3 μm, hereinafter abbreviated as LD-2)
UV absorber:
Sanduvor VSU made by Clariant Japan
N- (2-Ethylphenyl) -N ′-(2-ethoxyphenyl) oxalic acid diamide (Oxanilide ultraviolet absorber, hereinafter abbreviated as UVA-1)
Tinuvin 329 manufactured by Ciba Specialty Chemicals
(Benzotriazole ultraviolet absorber, hereinafter abbreviated as UVA-2)

  The above-mentioned various raw materials were each put in a tumbler at the mixing ratio for the base material or surface layer material shown in Tables 1-2, and after dry mixing for 10 minutes, a twin-screw extruder (TEX30α manufactured by Nippon Steel Works) was used. Then, kneading was performed at a melting temperature of 260 ° C. to obtain pellets for the base material or the surface layer material.

  The obtained base material and surface layer material pellets were each dried in advance under a drying condition of 125 ° C. × 2 hours. Next, the substrate pellets that had been pre-dried were put into a substrate extruder (VS40 single-screw extruder (L / D = 32, 40Φ) manufactured by Tanabe Plastics Co., Ltd.) for co-extrusion at 260 ° C. Supplied from the die substrate feed block. At the same time, pre-dried pellets for the surface layer are put into a surface layer extruder (PEX Giken PEX-25-24 single screw extruder (L / D = 24, 25Φ)), and the surface layer material is fed at 260 ° C. Was subjected to melt extrusion to obtain a coextruded sheet.

  Hereinafter, various evaluation items and measurement methods in the present invention will be described.

1. Luminance Two cold cathode tubes were placed on the back side of a coextruded sheet (90 × 50 × 2 mm thickness) cut, and the luminance on the surface of the test piece in the vertical direction between the lamps was measured. The luminance means the ratio of the luminous intensity directed in a certain direction per unit area in a plane perpendicular to the direction, and generally represents the degree of brightness of the light emitting surface [unit: (cd / m ² ). ]. Moreover, as a reference | standard of evaluation, the thing whose measured value of the brightness | luminance between lamps is 3200 cd / m < ² > or more was set to pass ((circle)), and less than 3200 cd / m < ² > was made disqualified (x). An outline of the measurement method is shown in FIG.

2. Mechanical strength After the obtained coextruded sheet was cut into a length of 6.3 mm, a width of 1.3 mm and a thickness of 2 mm to create a notched Izod test piece, the mechanical strength (impact Strength) was measured. As a criterion for evaluation, a sample having an impact strength of 30 kg · cm / cm or higher was determined to be acceptable (◯), and a sample having an impact strength of less than 30 kg · cm / cm was determined to be unacceptable (x).

3. Initial colorability and light resistance The obtained co-extruded sheet was cut into a thickness of 90 x 50 x 2 mm and placed in an ultra-accelerated weathering tester iSuper UV Tester (SUV-W13, manufactured by Iwasaki Electric Co., Ltd.) and irradiated for 6 hours. Was done. Thereafter, the yellowness index (YI) of the sample before and after irradiation was measured with a spectrophotometer (CMS-35SP manufactured by Murakami Color Research Laboratory) in accordance with ASTM D-1925. YI represents the degree of yellowness before irradiation. The smaller the YI, the smaller the yellowishness and the less the initial coloring. As the evaluation criteria for YI, those with a YI value of less than 3 were accepted (◯), and those with a YI value of 3 or more were rejected (x).
ΔYI represents the degree of yellowness before and after irradiation. The smaller ΔYI, the smaller the color change and the better the light resistance. As an evaluation standard for ΔYI, a value of ΔYI of less than 5 was accepted (◯), and a value of 5 or more was rejected (x).

4). Comprehensive judgment About the following Table 1-Table 3, in evaluation of the brightness | luminance between lamp | ramp, mechanical strength, initial coloring property, and light resistance, what satisfy | filled all was set as the pass ((circle)), and the thing which is not so was set as the disqualified (x).

  As shown in Table 1, when the configuration of the present invention was satisfied (Examples 1 to 7), all the evaluation items had sufficient performance.

On the other hand, as shown in Table 2, when the configuration of the present invention was not satisfied (Comparative Examples 1 to 7), each case had some defects.
Comparative Example 1 was a case where the blending amount of the silicone rubber particles having a methyl group was less than the specified amount, and although the mechanical strength, the initial coloring property and the light resistance passed, the inter-lamp luminance was inferior.
Comparative Example 2 was a case where the blending amount of the silicone rubber particles having a methyl group was larger than the specified amount, and although the mechanical strength, the initial coloring property and the light resistance passed, the inter-lamp luminance was inferior.
Comparative Example 3 was a case where silicone rubber particles having an epoxy group were used, and although the inter-lamp luminance, mechanical strength and light resistance passed, initial colorability was inferior.
Comparative Example 4 was a case where the blending amount of the oxanilide ultraviolet absorber was less than the prescribed amount, and the inter-lamp luminance, mechanical strength, and initial colorability passed, but the light resistance was inferior.
Comparative Example 5 was a case where the blending amount of the oxanilide ultraviolet absorber was larger than the prescribed amount, and although the inter-lamp luminance, mechanical strength and light resistance passed, the initial colorability was inferior.
Comparative Example 6 was a case where the blending amount of polycaprolactone was larger than the specified amount, and although the inter-lamp luminance, initial colorability and light resistance passed, the mechanical strength was inferior.
In Comparative Example 7, when different types of ultraviolet absorbers were used, the inter-lamp luminance, mechanical strength, and light resistance passed, but the initial colorability was inferior.

It is a figure which shows the measuring method of the brightness | luminance between lamps in this invention.

Explanation of symbols

A: Luminance meter B: Light beam C: Light diffusion plate D: Lamp (cold cathode tube)

Claims (6)

A light diffusing polycarbonate resin plate obtained by coextrusion molding a surface layer made of a polycarbonate resin composition containing an ultraviolet absorber as an essential component on at least one side of a substrate made of a polycarbonate resin composition containing a light diffusing agent as an essential component In
The light diffusing agent is a silicone rubber particle having a skeleton composed of a bifunctional siloxane unit and a trifunctional siloxane unit and an alkyl group on the surface, and an average particle diameter of 0.5 to 10 μm, and The content of the light diffusing agent is 0.1 to 1.5 parts by weight per 100 parts by weight of the polycarbonate resin used for the substrate, and the ultraviolet absorber is represented by the following general formula (1) The content of the ultraviolet absorber is 0.01 to 0.8 parts by weight per 100 parts by weight of the polycarbonate resin used for the surface layer,
A light diffusing polycarbonate resin plate characterized by the above.
General formula (1)

(In General Formula (1), R1 represents an alkyl group having 1 to 12 carbon atoms, and R2 represents an alkoxy group having 1 to 12 carbon atoms.) Light diffusion formed by coextrusion molding of a surface layer made of a polycarbonate resin composition containing an ultraviolet absorber as an essential component on at least one side of a substrate made of a polycarbonate resin composition containing light diffuser and polycaprolactone as an essential component In the polycarbonate resin plate,
The light diffusing agent is a silicone rubber particle having a skeleton composed of a bifunctional siloxane unit and a trifunctional siloxane unit and an alkyl group on the surface, and an average particle diameter of 0.5 to 10 μm, and The content of the light diffusing agent is 0.1 to 1.5 parts by weight per 100 parts by weight of the polycarbonate resin used for the substrate, and the ultraviolet absorber is represented by the following general formula (1) And the content of the ultraviolet absorber is 0.01 to 0.8 parts by weight per 100 parts by weight of the polycarbonate resin used for the surface layer, and the content of the polycaprolactone is based on 0.1 to 7 parts by weight per 100 parts by weight of polycarbonate resin used for the material,
A light diffusing polycarbonate resin plate characterized by the above.
General formula (1)

(In General Formula (1), R1 represents an alkyl group having 1 to 12 carbon atoms, and R2 represents an alkoxy group having 1 to 12 carbon atoms.) The light diffusing polycarbonate resin plate according to claim 1 or 2, wherein the ultraviolet absorber contains a compound represented by the following general formula (2) as an active ingredient.
General formula (2)

  The light-diffusing polycarbonate resin plate according to claim 1 or 2, wherein the blending amount of the ultraviolet absorber is 0.1 to 0.6 parts by weight per 100 parts by weight of the polycarbonate resin in the surface layer.   The light-diffusing polycarbonate resin plate according to claim 2, wherein the compounding amount of polycaprolactone is 0.3 to 5 parts by weight per 100 parts by weight of the polycarbonate resin used for the substrate.   3. The light diffusing polycarbonate resin plate according to claim 1, wherein the silicone rubber particles have an average particle diameter of 2 to 4 [mu] m.

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