JP2007153932A - Polycarbonate resin composition and its molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polycarbonate resin having permanent antistatic performance hardly causing an electrostatic hazard even in use of product not to mention in molding and processing without impairing a color tone and transparency characteristic of polycarbonate resin and its molding. <P>SOLUTION: The polycarbonate resin composition comprises a polycarbonate resin and a boric acid ester of a polyhydric alcohol fatty acid ester and/or its salt. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polycarbonate resin composition and a molded product thereof.

  Polycarbonate resins are used in various fields from civil engineering / building materials, automotive parts, electrical / electronic parts to household products because of their high mechanical strength and transparency, and excellent heat resistance and moldability.

  However, like general plastics, polycarbonate resin is also an electrical insulator, so it is easily charged. If static electricity is generated by frictional charging or the like, various static electricity failures may occur. For example, in the case of a film-shaped molded product, the films stick to each other with electrostatic attraction force, and the manufacturing operability is lowered, or the dust and dirt in the air are adsorbed to impair the aesthetics of the molded product. It causes troubles at various stages from manufacturing to use. In particular, electrical / electronic parts may cause serious problems such as malfunction of IC and destruction of memory.

In order to avoid such problems, it has been proposed to add an antistatic agent to the polycarbonate resin composition to impart antistatic properties. For example, Patent Document 1 describes a method of using an organic sulfonic acid metal salt such as sodium n-hexyl sulfonate and sodium dodecylbenzene sulfonate and a polyester ether having a specific structure as an antistatic agent. Describes a method in which a tertiary amine salt of an organic sulfonic acid such as stearindimethylamine salt or lauryl diethylamine salt of dodecylbenzenesulfonic acid and a phosphate having a specific structure are used as an antistatic agent. Patent Document 3 discloses a method of imparting antistatic performance to a polycarbonate resin using an ionic liquid.
Japanese Patent Laid-Open No. 9-40855 Japanese Patent Laid-Open No. 3-64368 Japanese Patent Laid-Open No. 2005-15573

  However, depending on the antistatic agent, the transparency of the molded product may be lowered, or the antistatic agent may be decomposed during heat molding to decompose the polycarbonate resin. In the case of the amine-based antistatic agent as described above, the product may be colored due to the interaction with other components contained in the resin composition. In addition, when an ionic liquid is used, although the initial antistatic performance is excellent, the antistatic performance may be reduced by simple water washing.

  The present invention has been made paying attention to the above circumstances, and its purpose is not to impair the color tone and transparency inherent in the polycarbonate resin, but also to the occurrence of electrostatic damage not only during molding and processing, but also during product use. An object of the present invention is to provide a polycarbonate resin having a difficult permanent antistatic performance and a molded product thereof.

  The polycarbonate resin composition of the present invention has a gist in that it contains a polycarbonate resin and a boric acid ester of a polyhydric alcohol fatty acid ester and / or a salt thereof.

  The inventors of the present invention have repeatedly studied to impart antistatic performance without impairing the properties (mechanical properties, heat resistance, electrical properties, transparency, etc.) inherent to the polycarbonate resin. The present inventors have found that a boric acid ester of an ester and / or a salt thereof is suitable as an antistatic agent for a polycarbonate resin composition, thereby completing the present invention. The boric acid ester of a polyhydric alcohol fatty acid ester and / or a salt thereof requires a higher temperature for molding processing than other thermoplastic resins (eg, polyolefin, polyester, styrene, acrylic resin, etc.) used as a molding material. No degradation occurs at the molding temperature of the polycarbonate resin, it is difficult to cause deterioration of the polycarbonate resin, and it is also difficult to interact with other compounding components. Can be given.

  The polycarbonate resin composition preferably contains an ultraviolet absorber, and more preferably contains fine particles. Molded articles obtained from the above polycarbonate resins are a preferred embodiment of the present invention.

  The present invention also includes a base sheet and a multilayer sheet having a surface layer on at least one side of the base sheet, the multilayer sheet obtained from the polycarbonate resin composition. The surface layer of the multilayer sheet is preferably a layer obtained from the polycarbonate resin composition of the present invention containing an antistatic agent or an antistatic agent and an ultraviolet absorber. The molded article and the multilayer sheet are suitably used for a light diffusing plate.

  The polycarbonate resin composition of the present invention containing a specific antistatic agent has little difference in color tone and transparency even when compared with the polycarbonate resin as the base resin.

  Molded articles made of the polycarbonate resin composition of the present invention are excellent in appearance because they do not easily adhere to dust even when subjected to water washing or ultraviolet rays, and are less likely to cause charging trouble such as malfunction or electric shock phenomenon, and have good antistatic performance. It is what has. Moreover, since the molded product according to the present invention is colorless and transparent, it is easy to obtain an arbitrary color tone by using various colorants. Therefore, it can be widely used in many fields such as electric / electronic equipment field, automobile field, machine field, and medical field. In particular, it is suitably used for applications requiring transparency, such as optical materials and electronic materials.

  The light diffusing plate of the present invention using the above polycarbonate resin composition has excellent antistatic performance and is unlikely to cause a decrease in luminance due to the adhesion of dust, thereby improving the image display quality of a liquid crystal display device. Is preferred.

  The present inventors have repeatedly studied to provide a polycarbonate resin composition capable of exhibiting excellent antistatic properties over a long period of time without impairing the unique properties of the polycarbonate resin. It has been found that all the above problems can be solved by using a boric acid ester of an alcohol fatty acid ester and / or a salt thereof, and the present invention has been completed. That is, the polycarbonate resin composition of the present invention is characterized by containing a polycarbonate resin and a boric acid ester of a polyhydric alcohol fatty acid ester and / or a salt thereof.

  First, the polycarbonate resin will be described. In the present invention, the polycarbonate resin is used as a base resin of the resin composition according to the present invention. Any of the above polycarbonate resins produced by a conventionally known method such as a phosgene method or a transesterification method can be used. For example, a dihydric phenol and a carbonate precursor are reacted by an interfacial polycondensation method or a melting method. What is obtained is preferably obtained.

  Representative examples of the dihydric phenol include 2,2-bis (4-hydroxyphenyl) propane [commonly known as bisphenol A], 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4 -Hydroxyphenyl) cyclohexane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfide And bis (4-hydroxyphenyl) sulfone. These dihydric phenols may be used alone or in combination of two or more. Of these dihydric phenols, bisphenol A is preferred.

  As the carbonate precursor, carbonyl halide, carbonate ester, haloformate, or the like is used. Specific examples include phosgene, diphenyl carbonate, dihaloformate of dihydric phenol, and the like.

  When a polycarbonate resin is produced by reacting the above dihydric phenol with a carbonate precursor by an interfacial polycondensation method or a melting method, a catalyst, a terminal terminator, a dihydric phenol antioxidant, etc., as necessary. May be used. The polycarbonate resin may be a branched polycarbonate resin copolymerized with a trifunctional or higher polyfunctional aromatic compound, or a polyester carbonate resin copolymerized with an aromatic or aliphatic difunctional carboxylic acid. Furthermore, what mixed 2 or more types of polycarbonate resin may be sufficient.

The molecular weight of the polycarbonate resin is usually 15,000 or more and 40,000 or less, preferably 18,000 or more and 35,000 or less in terms of viscosity average molecular weight. The viscosity average molecular weight referred to in the present invention is obtained by inserting a specific viscosity (ηsp) obtained from a solution obtained by dissolving 0.7 g of a polycarbonate resin in 100 mL of methylene chloride at 20 ° C. into the following equation.
ηsp / c = [η] + 0.45 × [η] ² c
[Η] = 1.23 × 10 ⁻⁴ M ^0.83
(However, c = 0.7, [η] is intrinsic viscosity)

  The polycarbonate resin composition of the present invention contains a boric acid ester of a polyhydric alcohol fatty acid ester and / or a salt thereof as an antistatic agent. The boric acid ester and / or salt thereof of the polyhydric alcohol fatty acid ester used in the present invention is not decomposed even at the molding temperature (about 170 to 330 ° C.) of the polycarbonate resin, so that the polycarbonate resin is derived from the decomposition of the antistatic agent. Inherent characteristics are unlikely to deteriorate. Further, the boric acid ester of a polyhydric alcohol fatty acid ester and / or a salt thereof used in the present invention hardly causes degradation such as hydrolysis of the polycarbonate resin even at the molding temperature of the polycarbonate resin. Furthermore, since the antistatic agent used in the present invention is also compatible with the polycarbonate resin, in the molded product using the resin composition, the transfer property of the antistatic agent to the surface of the molded product may deteriorate. Do not cause excessive bleed out. Therefore, if the polycarbonate resin composition of the present invention is used, a molded article having antistatic performance and transparency can be obtained.

The boric acid ester of a polyhydric alcohol fatty acid ester and / or a salt thereof according to the present invention has, for example, the following general formula.
[(RCOO) _m -XO] _n -B- (OA) _p
In the formula, R represents a saturated or unsaturated hydrocarbon group, preferably a saturated or unsaturated hydrocarbon group having 8 to 24 carbon atoms. X is a polyhydric alcohol residue, m is 1 to (q-1) [where q is the number of hydroxyl groups of the polyhydric alcohol], n is 1 to 3, A represents hydrogen, Na, K or Ca, p represents 3-n.

  The above (RCOO) having a saturated or unsaturated hydrocarbon group R represents a saturated or unsaturated fatty acid residue, and is a saturated or unsaturated fatty acid having 8 to 24 carbon atoms R. For example, capric acid, lauric acid, oleic acid, palmitic acid, stearic acid, behenic acid and the like can be mentioned. Of these, stearic acid is preferred.

  The polyhydric alcohol is preferably trivalent or higher, and specific examples include glycerin, erythritol, pentaerythritol, sorbitol, sucrose, and the like. Among these, glycerin, sorbitol, and sucrose are preferable, and glycerin is more preferable.

  The boric acid ester of a polyhydric alcohol fatty acid ester and / or a salt thereof is obtained by esterifying or transesterifying a boric acid or a lower alcohol ester of boric acid with a fatty acid ester of a polyhydric alcohol, and then Na, K or Ca. A method of neutralizing with a hydroxide, or after esterifying or transesterifying a polyhydric alcohol and boric acid or a lower alcohol ester of boric acid, and esterifying the resulting product with a fatty acid, It can be obtained by a method of neutralizing with a hydroxide of Na, K or Ca.

  These boric acid esters of polyhydric alcohol fatty acid esters and / or salts thereof may contain these precursors. That is, the antistatic agent used in the present invention includes an embodiment comprising a boric acid ester of a polyhydric alcohol fatty acid ester; an embodiment comprising a boric acid ester salt of a polyhydric alcohol fatty acid ester; a boric acid ester of a polyhydric alcohol fatty acid ester and a polyhydric acid In addition to the embodiment comprising a boric acid ester salt of an alcohol fatty acid ester, the charging used in the present invention also includes a case where at least one of a fatty acid ester of a polyhydric alcohol, a boric acid ester of a polyhydric alcohol or a salt thereof is included in each of the above embodiments. It is contained in the aspect of an inhibitor.

  As the antistatic agent, specifically, trade name “Register PE139” manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (Register is a registered trademark of Daiichi Kogyo Seiyaku Co., Ltd.) is preferably used. .

  The amount of the antistatic agent used is preferably 0.1 to 15 parts by mass with respect to 100 parts by mass of the polycarbonate resin according to the present invention. More preferably, it is 0.5 mass part or more, More preferably, it is 1 mass part or more, More preferably, it is 10 mass parts or less, More preferably, it is 5 mass parts or less. If the amount of the antistatic agent used is too small, it may be difficult to obtain the effect of preventing the adhesion of dust. On the other hand, even if it is added excessively, the effect commensurate with the amount added cannot be obtained.

In addition to the above-mentioned antistatic agent, the polycarbonate resin composition of the present invention includes other components such as organic ultraviolet rays such as triazole, acetophenone, and salicylic acid esters as long as the objects and effects of the present invention are not impaired. Absorbers, inorganic UV absorbers such as TiO ₂ , ZnO, CeO ₂ , heat stabilizers such as phosphorous acid, phosphoric acid, phosphite ester, phosphate ester, phosphonate ester, hindered phenols, etc. Additives such as antioxidants, bluing agents, tetrabromobisphenol A, low molecular weight polycarbonate of tetrabromobisphenol A, flame retardants such as decabromodiphenylene ether, flame retardant aids such as antimony trioxide, etc. as required The amount of expression may be blended.

  The said ultraviolet absorber can be mix | blended in order to improve the light resistance of the molded article which uses the polycarbonate resin composition which concerns on this invention as a raw material. As the ultraviolet absorber, any conventionally known ultraviolet absorber can be used, and is not particularly limited. For example, a salicylic acid phenyl ester ultraviolet absorber, a benzophenone ultraviolet absorber, a triazine ultraviolet absorber, Preferred examples include benzotriazole ultraviolet absorbers, cyclic imino ester type ultraviolet absorbers, hindered amine ultraviolet absorbers, and hybrid ultraviolet absorbers having both a hindered phenol structure and a hindered amine structure in the molecule.

  Specific examples of salicylic acid phenyl ester ultraviolet absorbers include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

  Specific examples of the benzophenone ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2-hydroxy-4-benzyloxybenzophenone. 2-hydroxy-4-methoxy-5-sulfoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxytrihydridolate benzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2 ′, 4 , 4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxy-5-sodiumsulfoxybenzophenone, bis (5-benzoyl) -4-hydroxy-2-me Kishifeniru) methane, 2-hydroxy -4-n-dodecyloxy benzophenone, 2-hydroxy-4-methoxy-2'-carboxy benzophenone.

  Specific examples of the triazine ultraviolet absorber include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-hexyloxyphenol.

  Specific examples of the benzotriazole ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-t-octylphenyl) benzotriazole, 2- (2-hydroxy-3,5-dicumylphenyl) phenylbenzotriazole, 2- (2-hydroxy-3-t-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2,2′-methylenebis [4 -(1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole 2- (2-hydroxy-3,5-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3 5-di-t-amylphenyl) benzotriazole, 2- (2-hydroxy-5-t-octylphenyl) benzotriazole, 2- (2-hydroxy-5-t-butylphenyl) benzotriazole, 2- (2 -Hydroxy-4-octoxyphenyl) benzotriazole, 2,2′-methylenebis (4-cumyl-6-benzotriazolephenyl), 2,2′-p-phenylenebis (1,3-benzoxazin-4-one ), 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimidomethyl) -5-methylphenyl] benzotriazole and the like.

  Specific examples of the cyclic imino ester ultraviolet absorber include 2,2′-p-phenylenebis (3,1-benzoxazin-4-one), 2,2 ′-(4,4′-). And diphenylene) bis (3,1-benzoxazin-4-one) and 2,2 ′-(2,6-naphthalene) bis (3,1-benzoxazin-4-one).

  Specific examples of the hindered amine ultraviolet absorber include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and bis (1,2,2,6,6-pentamethyl-4-). Piperidyl) sebacate and the like.

  Specific examples of the hybrid ultraviolet absorber having both a hindered phenol structure and a hindered amine structure in the molecule include 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2. -Bis (1,2,2,6,6-pentamethyl-4-piperidyl) -n-butylmalonate, 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl Oxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine and the like.

  As an inorganic ultraviolet absorber, the main component is a metal of Zn, Ti, or Ce in that it selectively absorbs ultraviolet rays and has a low influence on the visible light transmittance of the resin composition and the molded product. Particles made of metal oxide are preferably used. From the viewpoint of ensuring the transparency of the resin composition or molded product, the primary particle diameter of these metal oxide particles is preferably 0.1 μm or less, more preferably 0.05 μm or less, and still more preferably. 0.02 μm or less. The primary particle diameter is the crystallite diameter measured by the powder X-ray diffraction method or B.I. E. It means the particle diameter calculated from the specific surface area measured by the T method.

  These ultraviolet absorbers may be used alone or in combination of two or more. Among the above ultraviolet absorbers, 2-hydroxy-4-n-octoxybenzophenone, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-hexyloxyphenol, 2- (2-hydroxy-5-t-octylphenyl) benzotriazole, 2- (2-hydroxy-3,5-dicumylphenyl) phenylbenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methyl) Phenyl) -5-chlorobenzotriazole, 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2,2 '-P-phenylenebis (3,1-benzoxazin-4-one) is particularly preferred.

  The ultraviolet absorber is preferably used in an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the polycarbonate resin according to the present invention. More preferably, it is 0.3 mass part or more, More preferably, it is 0.5 mass part or more, It is preferable that it is 15 mass parts or less, More preferably, it is 10 mass parts or less. If the amount used is too small, the effect of preventing the influence of ultraviolet rays may be small. Conversely, even if blended excessively, it is difficult to obtain an effect commensurate with the blended amount.

  The polycarbonate resin composition according to the present invention may further contain a phosphorus-containing heat stabilizer in order to prevent a decrease in molecular weight and a deterioration in hue during molding. Examples of such heat stabilizers include phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid, and esters thereof.

  Specifically, triphenyl phosphite, tris (nonylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl Phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2,6-di-t-butyl-4 -Methylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-) t- Tylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tributyl phosphate, triethyl phosphate, trimethyl phosphate, triphenyl phosphate, diphenyl monooxoxenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, tetrakis (2,4 -Di-isopropylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-n-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t -Butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t-butylphenyl) -4,3'-biphenylenediphosphonite, tetrakis (2 4-di-t-butylphenyl) -3,3'-biphenylenediphosphonite, tetrakis (2,6-di-isopropylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-) n-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,6-di-t-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,6-di-t-) Butylphenyl) -4,3′-biphenylenediphosphonite, tetrakis (2,6-di-t-butylphenyl) -3,3′-biphenylenediphosphonite, bis (2,4-di-t-butylphenyl) ) -Biphenylphosphonite, benzene phosphonate dimethyl, benzene phosphonate diethyl, benzene phosphonate dipropyl and the like. These heat stabilizers may be used alone or in combination of two or more. Among the above heat stabilizers, tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylenediphosphonite, bis (2 , 4-Di-t-butylphenyl) -biphenylphosphonite is preferred.

  The amount of the heat stabilizer used is preferably 0.001 part by mass or more and 0.15 part by mass or less with respect to 100 parts by mass of the polycarbonate resin.

  In the polycarbonate resin composition of the present invention, a bluing agent can be blended in order to counteract the yellowishness of the light diffusion plate based on the polycarbonate resin or the ultraviolet absorber in the product made from the resin composition. As the bluing agent, any bluing agent that is usually used for polycarbonate resin can be used without any problem. For example, anthraquinone dyes are preferred because they are readily available.

As a specific bluing agent, for example, the general name Solvent Violet 13 [CA. No (Color Index No) 60725; trade name “Macrolex Violet B” manufactured by Bayer, “Diaresin Blue G” manufactured by Mitsubishi Chemical (Diaresin is a registered trademark of Mitsubishi Chemical Corporation), Sumitomo Chemical "Sumiplast Violet B"] (Sumiplast is a registered trademark of Sumitomo Chemical Co., Ltd.), generic name Solvent Violet 31 [CA. No 68210; trade name “Diaresin Violet D” manufactured by Mitsubishi Chemical Corporation], generic name Solvent Violet 33 [CA. No 60725; trade name “Diaresin Blue J” manufactured by Mitsubishi Chemical Corporation], generic name Solvent Blue 94 [CA. No 61500; trade name “Diaresin Blue N” manufactured by Mitsubishi Chemical Corporation], generic name Solvent Violet 36 [CA. No 68210; trade name “Macrolex Violet 3R” manufactured by Bayer AG, generic name Solvent Blue 97 [trade name “Macrolex Violet RR” manufactured by Bayer AG], and general name Solvent Blue 45 [CA. No. 61110; trade name “Tetrazole Blue RLS” manufactured by Sand Corp.] is a typical example. These bluing agents are preferably blended at a ratio of usually 0.3 × 10 ⁻⁴ parts by mass to 2 × 10 ⁻⁴ parts by mass with respect to 100 parts by mass of the polycarbonate resin.

  Furthermore, in the polycarbonate resin composition of the present invention, a fatty acid ester compound can be used for the purpose of improving the releasability from the mold during molding. Such a fatty acid ester is preferably a partial ester or a total ester of a monohydric or polyhydric alcohol having 1 to 20 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms. Such partial esters or total esters of monohydric or polyhydric alcohols and saturated fatty acids include stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, stearic acid monosorbate, behenic acid monoglyceride, pentaerythritol monostearate, pentaerythritol. Tetrastearate, pentaerythritol tetrapelargonate, propylene glycol monostearate, stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, isopropyl palmitate, biphenyl biphenate, sorbitan monostearate, 2-ethylhexyl stearate Rate and so on. These fatty acid esters may be used alone or in combination of two or more. Of these fatty acid esters, stearic acid monoglyceride, stearic acid triglyceride, and pentaerythritol tetrastearate are preferred. The amount of the fatty acid ester used is preferably 0.001 part by mass or more and 0.5 part by mass or less with respect to 100 parts by mass of the polycarbonate resin.

  In addition to the other components described above, the polycarbonate resin composition of the present invention may further contain additives such as stabilizers, antioxidants, plasticizers, dispersants, optical brighteners, and pigments. . The blending amount of these additives may be appropriately adjusted according to the type and purpose thereof, and is not particularly limited.

  The polycarbonate resin composition of the present invention is an embodiment in which the above-mentioned antistatic agent (and other components) is mixed in a powder or pellet-like polycarbonate resin; the above-mentioned antistatic agent (and other components) is kneaded into the polycarbonate resin. Or an embodiment in which a polycarbonate resin and an antistatic agent (and other components) are dissolved or dispersed in a solvent.

  Examples of the mixer that can be used at this time include a ribbon blender and a Henschel mixer. In addition, when an antistatic agent or the like is kneaded into the polycarbonate resin in the absence of a solvent, a kneader such as a single screw extruder, a twin screw extruder, a Banbury mixer, or a kneader is preferably used. In addition, it is preferable that the heating temperature at the time of kneading shall be 240-320 degreeC.

  Next, a molded product made from the polycarbonate resin composition will be described.

  The shape of the molded product according to the present invention is not particularly limited and can be appropriately determined according to the application. Moreover, the obtained molded product may have a single layer structure or a laminated structure composed of two or more layers. In addition, when it has a laminated structure, all the layers may be formed with the polycarbonate resin composition of the present invention, or at least one of the plurality of layers constituting the laminated structure is the polycarbonate resin composition of the present invention. You may be comprised with the thing. In the latter case, from the viewpoint of the antistatic effect, the surface layer (outermost layer) is preferably composed of the polycarbonate resin composition of the present invention.

  Specific configurations in the case of having a laminated structure include a base sheet and a multilayer sheet having a surface layer obtained from the polycarbonate resin composition of the present invention on at least one side of the base sheet. The thickness of the surface layer is preferably 0.1 to 1000 μm. More preferably, it is 1-100 micrometers, More preferably, it is 5-50 micrometers.

  The method for producing a molded product according to the present invention is not particularly limited, and any method used as a method for molding a thermoplastic resin can be adopted, and may be appropriately selected according to the size and shape of the molded product. Specific molding methods include extrusion molding, injection molding, blow molding, compression molding, transfer molding, rotational molding, calendering, and the like. Moreover, after shaping | molding by the said shaping | molding method, you may give secondary shaping | molding, such as cutting, shearing, punching, punching, milling cutter processing, file processing, buff processing, joining processing, bending processing.

  For example, in the case of producing a molded article having a single layer structure by injection molding, a molding material such as the polycarbonate resin composition and other additives is supplied from a hopper provided in the injection molding machine into a heating cylinder. Then, this may be softened by heating in a heating cylinder, and a molding material may be injected into a mold from a nozzle provided at one end of the heating cylinder, and then cooled and solidified. At this time, the cylinder temperature is 240 to 320 ° C. (more preferably 250 to 310 ° C., more preferably 260 to 300 ° C.), and the mold temperature is 80 ° C. or more (more preferably 100 ° C. or more, more preferably 120 ° C. or more). ) Is preferred.

  Further, if a molded product having a laminated structure, for example, the above-described multilayer sheet is produced by an extrusion molding method (coextrusion), two or more extruders may be used. The type of the extruder is not particularly limited, and any conventionally known extruder such as a single screw extruder or a twin screw extruder can be used. Specifically, the molding material constituting the base sheet, the surface layer, or other layers is supplied from the hopper provided in each extruder into the extruder (heating cylinder), and is softened while being heated and kneaded. The base material sheet is formed by feeding the molding material constituting each layer into one common die, winding the film-like molded product extruded from the die around a take-up device while cooling, and cutting it into a predetermined shape. A molded product (multilayer sheet) having a surface layer is obtained. At this time, the temperature of the heating cylinder is 240 to 320 ° C. (more preferably 250 to 310 ° C., more preferably 260 to 300 ° C.), and the cooling rate is 5 to 100 ° C./min (more preferably 10 to 80 ° C./min, More preferably, it is preferably 20 to 70 ° C./min. Moreover, it is preferable that ratio L / D of the length L of the screw in a heating cylinder and the diameter D is 20-60, More preferably, it is 25-50.

  The surface layer can also be formed by applying a solution in which a polycarbonate resin, an antistatic agent or the like is dissolved on the base sheet.

  It is recommended that the molding process be performed at a resin temperature of 240 to 330 ° C. Since the polycarbonate resin has a higher glass transition temperature than other thermoplastic resins, migration and diffusion of the antistatic agent from the inside of the molded product to the surface due to the micro-brown motion of the molecular chain hardly occur after molding. For this reason, it is not possible to take a method of obtaining an antistatic effect for a long period of time by utilizing the migration behavior of the antistatic agent to the surface, and the antistatic effect decreases with time due to cleaning of the surface of the molded article. There is a case. Such a decrease in the antistatic effect over time can be suppressed to some extent by increasing the amount of the antistatic agent added. However, the increase in the amount of the antistatic agent used is from the viewpoint of processability and cost of the molded product. Is also not preferable. Therefore, it is recommended to control the heating conditions and cooling rate during the molding process or to perform surface treatment to form a concentrated layer of the antistatic agent near the surface of the molded product. For example, at the time of molding, the resin temperature is preferably 240 to 330 ° C. (more preferably 250 to 310 ° C., more preferably 260 to 300 ° C.), and the cooling of the molded product is 5 to 100 ° C./min (more preferably 10 to 80 ° C./min, more preferably 20 to 70 ° C./min) is recommended.

  Examples of the surface treatment include corona treatment and frame treatment. All of these methods may be adopted, but even when any one of them is adopted, it is effective in suppressing the decrease in the antistatic effect over time.

  In addition, polycarbonate resin may be hydrolyzed when heated in the presence of a certain amount of water, so the polycarbonate resin used as a molding material is sufficiently pre-dried regardless of which molding method is used. It is preferable to keep it. The drying conditions may be appropriately determined. For example, it is preferable that the polycarbonate resin composition pellets are heated at 100 ° C. or higher for several hours and dried until the water absorption is about 0.015%.

As described above, since the polycarbonate resin composition of the present invention contains a specific antistatic agent, a molded product produced using such a resin composition as a raw material is compared with a general plastic molded product. The electrical resistivity of the surface is low, and resistance to dust adhesion (dustproof performance) and malfunction of electronic devices are unlikely to occur. Specifically, the area resistivity of the surface of the molded article formed with the polycarbonate resin composition of the present invention is preferably 10 ¹⁴ Ω or less, more preferably 10 ¹³ Ω or less, and even more preferably 10 ¹² Ω or less. If the sheet resistivity exceeds 10 ¹⁴ Ω, it may be difficult to prevent dust adhesion and machine malfunction. The above-mentioned sheet resistivity is a value measured with a high resistance meter measured at a measurement voltage of 250 V and a charge time of 60 seconds after the measurement sample is left in an atmosphere of a temperature of 23 ° C. and a humidity of 60% RH for 24 hours. is there.

  The molded article comprising the polycarbonate resin composition of the present invention preferably has a haze of 0% or more and 20% or less, more preferably 0% or more and 10% or less, and / or a total light transmittance. It is preferably 70% or more and 100% or less, more preferably 85% or more and 100% or less. The haze and total light transmittance are values measured by a measuring method based on JIS K7105. In addition, the value of the said haze and total light transmittance means the value when the polycarbonate resin composition of this invention does not contain a pigment etc.

  Accordingly, the polycarbonate resin composition of the present invention can be used in electrical / electronic devices (television, personal computers, optical information recording medium substrates such as CDs and DVDs, optical fibers, etc.), precision devices (cameras, watches, etc.), security products. (Dust-proof glasses, helmets, etc.), household items (electrical appliances such as lighting equipment, tableware toys, etc.), building / building materials (such as glass substitutes), automotive interior parts and exteriors, medical supplies, food packaging films It is suitably used as a raw material.

  Here, the case where the light-diffusion plate used for the backlight unit of a liquid crystal display device is manufactured using the polycarbonate resin composition of this invention as a raw material is demonstrated concretely.

  In a liquid crystal display device such as a mobile phone, a television, or a personal computer, a backlight unit is disposed behind the liquid crystal display panel, and an image is displayed by supplying light from the backlight to the liquid crystal display panel. As such a backlight unit, there are a side type backlight unit mainly provided in a small liquid crystal display device, a direct type backlight unit used in a large liquid crystal display device exceeding 15 inches, and the like. In these backlight units, the light diffusing plate plays a role of making the light from the light source a uniform surface light source and erasing the shape of the light source. In particular, the light diffusing plate provided in the direct type backlight unit In order to make a display image clear, it is required to supply light with uniform and high luminance.

  The molded product of the present invention obtained from the polycarbonate resin composition has high transparency and an excellent antistatic effect, so that it can suppress the uniformity of light and the decrease in luminance caused by the ingress of dust into the backlight unit. It is effective and can be suitably used as a light diffusing plate of either a side type or a direct type backlight unit. Moreover, when the said polycarbonate resin composition contains a ultraviolet absorber, the deterioration prevention effect by the ultraviolet-ray contained in a light source is also acquired.

  That is, the light diffusing plate of the present invention is characterized by including the above-described antistatic agent or the polycarbonate resin composition of the present invention containing the antistatic agent and the ultraviolet absorber.

  As a specific aspect of the light diffusion plate of the present invention, a single-layer light diffusion plate containing the polycarbonate resin composition and fine particles (first aspect); a base sheet, and a surface on at least one side of the base sheet And a light diffusing plate having a multilayer structure in which the surface layer is made of the polycarbonate resin composition of the present invention (second embodiment). Of course, the second aspect includes an aspect in which the base sheet has a laminated structure and an aspect in which another layer is included between the base sheet and the surface layer. “At least one side” means either one or both of the front surface and the back surface of the base sheet.

  First, the first aspect will be described. The light diffusing plate of the first embodiment is a molded article made of a polycarbonate resin composition containing the antistatic agent or the antistatic agent and an ultraviolet absorber, and further comprising fine particles. The fine particles are preferably uniformly dispersed in the light diffusion plate.

  The material of the fine particles can be any of organic, inorganic, or metal-based materials such as (meth) acrylic resin, styrene resin, polyurethane resin, polyester. Organic materials such as synthetic resins such as resin, silicone resin, fluorine resin, and copolymers thereof; glass; clay compounds such as smectite and kaolinite; metal (water) oxides such as silica and alumina; metal (acid) Examples thereof include nitrides; metal (acid) fluidized products; metal (acid) carbides; inorganic materials such as metal salts such as metal sulfates; Of these materials, silicone resins and silica are particularly suitable.

  The fine particles may be formed of a single material or may be formed of two or more kinds of materials such as an organic / inorganic composite. It may be composed of two or more kinds of fine particles having different values.

  Examples of the shape of the fine particles include a spherical shape, a flat shape, an ellipsoidal shape, a polygonal shape, and a plate shape. The fine particles having these shapes may be used alone or in combination of two or more. Among the fine particles having these shapes, spherical particles are suitable, but they have a light diffusibility stronger than spherical particles, and high luminance can be obtained with a small amount of addition, so that they are flat, elliptical, In some cases, irregularly shaped particles such as polygonal shapes and plate shapes are suitable.

  The average particle diameter of the fine particles is preferably 0.1 μm or more and 30 μm or less, more preferably 0.5 μm or more and 25 μm or less, and further preferably 1 μm or more and 20 μm or less. If the average particle size is less than 0.1 μm, it may be difficult to sufficiently diffuse the light incident on the thin film. On the other hand, when the average particle diameter exceeds 30 μm, the amount of light passing through the thin film is decreased, and the luminance may be decreased. The average particle diameter of each fine particle is a value obtained by simply averaging the particle diameter of 100 arbitrary fine particles observed with a microscope. When each fine particle is irregularly shaped, the average of the maximum diameter and the minimum diameter is defined as the particle diameter.

  The amount of the fine particles used is preferably 0.1 parts by mass or more and 20 parts by mass or less, more preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polycarbonate resin constituting the light diffusion plate. is there. If the amount used is less than 0.1 parts by mass, the light incident on the light diffusion plate may not be sufficiently diffused. On the other hand, when the amount used exceeds 20 parts by mass, it may be difficult to extrude the light diffusing plate, or the amount of light passing through the light diffusing plate may decrease, resulting in a decrease in luminance.

  Next, the light diffusion plate of the second aspect will be described. The light diffusion plate of the second aspect has a base sheet and a surface layer on at least one side of the base sheet, and the surface layer is made of the polycarbonate resin composition of the present invention. As a specific configuration of the light diffusing plate having the second aspect, for example, a light diffusing plate having a surface layer made of the above polycarbonate resin composition containing an antistatic agent on one side of the base sheet; A light diffusing plate having a surface layer made of a polycarbonate resin composition on both sides of the substrate; a light diffusing plate having a surface layer made of a polycarbonate resin composition containing an antistatic agent and an ultraviolet absorber on one side of the substrate sheet: the substrate sheet A light diffusing plate having a surface layer made of a polycarbonate resin composition containing an antistatic agent and an ultraviolet absorber on both sides of the substrate; between the base sheet and the surface layer made of a polycarbonate resin composition containing an antistatic agent A light diffusing plate having a layer containing an ultraviolet absorber; having a surface layer made of a polycarbonate resin composition containing an antistatic agent on one side of the base sheet A light diffusing plate having a layer containing an ultraviolet absorber on the other surface; a surface layer containing an antistatic agent on one surface of the substrate sheet; and an ultraviolet absorber on the other surface of the substrate sheet And a light diffusing plate having a layer containing and a surface layer containing an antistatic agent in this order.

  When the surface layer contains an ultraviolet absorber or when a layer containing an ultraviolet absorber is provided, it is preferable to arrange the layer containing the ultraviolet absorber at a position closer to the light source of the light diffusion plate. . With this configuration, the effect of the ultraviolet absorber is effectively exhibited, and the light diffusing plate exhibits high light resistance. Therefore, the image display quality of the liquid crystal display device can be reduced with time.

  The surface layer is preferably made of the polycarbonate resin composition described above, and the thickness is preferably 0.1 to 1000 μm. More preferably, it is 1 micrometer or more, More preferably, it is 5 micrometers or more, It is more preferable that it is 500 micrometers or less, More preferably, it is 100 micrometers or less. If the surface layer is too thick, the amount of light passing through the light diffusing plate may decrease and the brightness may decrease.If the surface layer is too thin, the strength of the surface layer may be difficult to obtain, and molding may be difficult. is there.

  The base material sheet constituting the light diffusion plate of the second aspect needs to be light transmissive. As a specific degree of light transmittance (when the base sheet does not contain fine particles), the haze of the base sheet is preferably 0% or more and 20% or less, more preferably 0% or more and 10%. And / or the total light transmittance is preferably 70% or more and 100% or less, more preferably 85% or more and 100% or less. The haze and total light transmittance are values measured by a measuring method based on JIS K7105. In addition, the value of the said haze and total light transmittance means the value when a base material sheet does not contain the microparticles | fine-particles mentioned later.

  As the material of the base sheet, it is preferable to use a thermoplastic resin. For example, polycarbonate resin; (meth) acrylic resin such as polymethyl methacrylate; styrene resin such as polystyrene; acrylic-styrene copolymer; norbornene Cyclic olefin-based resins such as resin-based resins; Of these thermoplastic resins, polycarbonate resins are particularly suitable, and the above-described polycarbonate resin composition of the present invention is also suitably used.

  The base sheet may be formed of a single material or two or more materials, and may be formed of a single layer or a plurality of layers. Good.

  The thickness of the base sheet is preferably 0.5 mm or more and 5 mm or less, more preferably 1 mm or more and 3 mm or less. When the thickness of the base sheet is less than 0.5 mm, the mechanical strength of the light diffusing plate may be lowered. On the other hand, when the thickness of the base sheet exceeds 5 mm, the amount of light passing through the light diffusing plate is decreased, and the luminance may be decreased.

  You may mix | blend additives, such as a stabilizer, antioxidant, a plasticizer, a dispersing agent, and a fluorescent whitening agent, with a base material sheet, for example. What is necessary is just to adjust suitably the compounding quantity of these additives according to the kind etc., and it is not specifically limited.

  In the light diffusing plate of the second aspect, the fine particles are added to either the surface layer or the base sheet in order to diffuse the light from the light source uniformly and satisfactorily and improve the uniformity and brightness of the light. It is preferable to contain. Such fine particles are preferably dispersed substantially uniformly.

  The same material, shape, and average particle diameter as those described in the first embodiment can be used. However, the amount of fine particles used when the fine particles are contained in the surface layer is preferably 0.1 parts by mass or more and 20 parts by mass or less, more preferably 0.8 parts by mass with respect to 100 parts by mass of the resin constituting the surface layer. 2 parts by mass or more and 10 parts by mass or less. If the amount used is less than 0.1 parts by mass, the light incident on the light diffusion plate may not be sufficiently diffused. On the other hand, when the amount used exceeds 20 parts by mass, it may be difficult to mold the light diffusing plate, or the amount of light passing through the light diffusing plate may decrease, resulting in a decrease in luminance.

  Since the light diffusing plate of the present invention is a surface light source having a uniform luminance by uniformly diffusing light from the light source, the haze is 70% or more in any of the first and second aspects. More preferably, it is 80% or more, more preferably 90% or more, and / or the total light transmittance is preferably 40% or more, more preferably 50% or more, still more preferably 60% or more. It is.

Brightness of light passing through the light diffusion plate of the present invention is preferably 3000 cd / ^{m 2} or more, more preferably 3500 cd / ^{m 2} or more, still more preferably 4000 cd / ^{m 2} or more. If the luminance is less than 3000 cd / m ² , the display image of the liquid crystal display device may become dark and the image may become unclear.

The measurement of the luminance of the light passing through the light diffusion plate can be performed using, for example, a luminance meter (BM-7 type, manufactured by Topcon Corporation). The brightness value is determined by setting the atmosphere in the measurement chamber to a temperature of 25 ° C. and a humidity of 60% RH, and a direct type backlight unit for a 15-inch type liquid crystal display device (the intensity of the cold cathode tube lamp is 10,000 cd / m ^2). In this way, a measurement sample having a length of 231 mm and a width of 321 mm is incorporated into the lamp intensity, and the luminance (cd / m ² ) at nine points in the measurement sample is measured, which means an average value. Note that the luminance measurement sites are the center point of the light diffusing plate, two points at a position 77 mm away from the center in the vertical direction, and six points at a position 107 mm away from these three points in the horizontal direction. The total was 9 points. The measurement distance was 50 cm and the viewing angle was 1 °.

  The manufacturing method of the light diffusing plate according to the present invention is not particularly limited, and may be appropriately selected according to the mode of the light diffusing plate, such as injection molding, extrusion molding, and compression molding. For example, if the light diffusing plate of the first aspect is manufactured by injection molding, the polycarbonate resin composition, fine particles, and other additives are introduced into a heating cylinder from a hopper provided in the injection molding machine. A molding material such as the above may be supplied, heated and softened in a heating cylinder, and the molding material may be injected into a mold from a nozzle provided at one end of the heating cylinder, and then cooled and solidified. At this time, the cylinder temperature is preferably 240 to 320 ° C. (more preferably 250 to 310 ° C., more preferably 260 to 300 ° C.), and the mold temperature is preferably 80 ° C. or more (more preferably 100 ° C. or more, further Preferably 120 ° C. or higher).

  If the light diffusing plate of the second aspect is produced by an extrusion molding method (coextrusion), two or more extruders may be used. The type of the extruder is not particularly limited, and any conventionally known extruder such as a single screw extruder or a twin screw extruder can be used. Specifically, the molding material constituting the base sheet, the surface layer, or other layers is supplied from the hopper provided in each extruder into the extruder (heating cylinder), and is softened while being heated and kneaded. The base material sheet is formed by feeding the molding material constituting each layer into one common die, winding the film-like molded product extruded from the die around a take-up device while cooling, and cutting it into a predetermined shape. A multilayer sheet having a surface layer on the surface, that is, the light diffusion plate of the present invention is obtained. At this time, the temperature of the heating cylinder is 240 to 320 ° C. (more preferably 250 to 310 ° C., more preferably 260 to 300 ° C.), and the cooling rate is 5 to 100 ° C./min (more preferably 10 to 80 ° C./min, More preferably, it is 20-70 degreeC / min. Moreover, it is preferable that ratio L / D of the length L of the screw in a heating cylinder and the diameter D is 20-60, More preferably, it is 25-50.

  The surface layer may be formed by applying a solution in which a polycarbonate resin, an antistatic agent or the like is dissolved on the base sheet.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. It is also possible to implement, and they are all included in the technical scope of the present invention. Unless otherwise specified, mass parts may be expressed as “parts” and mass% as “%”. Various measurements and evaluation methods were performed according to the following.

<Dustproof performance>
The area resistivity of the flat plate obtained in the following examples was measured to evaluate the dustproof performance. When the flat plate had a laminated structure (Examples 7 and 9), the sheet resistivity of the layer containing the antistatic agent was measured and evaluated.

  For the area resistivity, the sample for evaluation was allowed to stand in an atmosphere of a temperature of 23 ° C. and a humidity of 60% RH for 24 hours, and then a high resistance meter (HP4339A, manufactured by Hewlett-Packard) and a sensor (16008, manufactured by Hewlett-Packard) It measured using. The measurement voltage was 250 V and the charge time was 60 seconds.

<Accelerated light resistance test>
The sample for evaluation was irradiated with ultraviolet rays (irradiation intensity: 100 mW / cm ² ) for 20 hours using an ultraviolet irradiation device (eye super tester W14 type, manufactured by Iwasaki Electric Co., Ltd.) in an atmosphere at a temperature of 63 ° C. Performance was measured.

<Permanent antistatic evaluation>
The sample for evaluation was immersed in an ultrasonic cleaner (US-3R, manufactured by ASONE Co., Ltd.) set to a water temperature of 40 ° C., washed for 30 minutes, and then the sheet resistivity was measured according to the dustproof performance evaluation method. Those having an area resistivity of 10 ¹⁴ or less after washing with water were evaluated as having permanent antistatic properties.

<Total light transmittance, haze measurement, and light transmittance evaluation>
Using a turbidimeter (NDH200, Nippon Denshoku Industries Co., Ltd.), the total light transmittance and haze of the sample for evaluation were measured. As a transparent material, a flat light plate having a thickness of 2 mm is evaluated as having a total light transmittance of 85% or more and haze of 3% or less as a transparent material, and a light diffusing material has a total light transmittance of 50 to 75%. A haze of 90% or more was evaluated as being suitable as a light diffusion material.

<Measurement of brightness>
The brightness of light transmitted through the evaluation sample was measured using a brightness meter (BM-7 type, manufactured by Topcon Corporation). The atmosphere in the measurement chamber is 25 ° C. and the humidity is 60% RH, and the direct-type backlight unit for a 15-inch liquid crystal display device (the lamp intensity is set so that the intensity of the cold cathode tube lamp is 10,000 cd / m ^2. ), A measurement sample having a length of 231 mm and a width of 321 mm was incorporated, and the luminance (cd / m ² ) at nine points in the measurement sample was measured, and the average value was taken as the luminance. Note that the luminance measurement site is composed of the center point of the measurement sample, two points at a position 77 mm away from the center in the vertical direction, and six points at a position 107 mm away from these three points in the horizontal direction. The total was 9 points. The measurement distance was 50 cm and the viewing angle was 1 °.

[Example 1]
100 parts by weight of polycarbonate resin (“E2000FN (trade name)” manufactured by Mitsubishi Engineering Plastics) and antistatic agent A (“Register PE139 (trade name)”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., boric acid of fatty acid mono and diglyceride Esters and their salts) are dry blended and supplied to an injection molding machine (“PS40E5ANE”, manufactured by Nissei Plastics), heat-softened in a cylinder at a temperature of 280 ° C., and injected into a mold at a temperature of 110 ° C. A square flat plate (base material sheet) having a side of 110 mm and a thickness of 2 mm was produced.

The obtained flat plate was a colorless and transparent plate having a total light transmittance of 89% and a haze of 1%. The area resistivity of this flat plate is 3.0 × 10 ¹² Ω, the area resistivity after washing with water is 2.0 × 10 ¹⁴ Ω, and the area resistivity after the light resistance test is 1.0 × 10 ¹³ Ω. There is little change in the area resistivity and the area resistivity after the light resistance test and after washing with water, and it is considered to have permanent antistatic performance. These evaluation results are shown in Table 1.

[Example 2]
A flat plate was produced in the same manner as in Example 1 except that the amount of the antistatic agent A used was 0.5 parts by mass. The obtained flat plate was a colorless and transparent plate having a total light transmittance of 89% and a haze of 1%. The flat sheet had a sheet resistivity of 4.0 × 10 ¹³ Ω, an area resistivity after washing with water of 3.0 × 10 ¹³ Ω, and a sheet resistivity after light resistance test of 1.0 × 10 ¹⁴ Ω. The evaluation results are shown in Table 1.

[Example 3]
A flat plate was produced in the same manner as in Example 1 except that the amount of the antistatic agent A used was 3 parts by mass. The obtained flat plate was a colorless and transparent plate having a total light transmittance of 89% and a haze of 1%. The flat sheet had a sheet resistivity of 1.0 × 10 ¹² Ω, a sheet resistivity after washing with water of 1.5 × 10 ¹² Ω, and a sheet resistivity after light resistance test of 4.0 × 10 ¹³ Ω. The evaluation results are shown in Table 1.

[Example 4]
100 parts by weight of polycarbonate resin, 5 parts by weight of antistatic agent A, and 0.5 part by weight of UV absorber (“Tinuvin 329 (trade name)”, manufactured by Ciba Specialty Chemicals) were dry blended, and the same method as in Example 1 A flat plate was manufactured.

The obtained flat plate was a colorless and transparent plate having a total light transmittance of 88% and a haze of 1%. The plate has an area resistivity of 3.2 × 10 ¹² Ω, an area resistivity after washing with water of 4.0 × 10 ¹² Ω, and an area resistivity after a light resistance test of 1.0 × 10 ¹³ Ω. It has excellent light resistance as well as prevention performance. The evaluation results are shown in Table 1.

[Example 5]
A single-layer sheet extrusion apparatus (“PMS 50-32”) that is dry-blended with 100 parts by weight of polycarbonate resin, 1 part by weight of antistatic agent A, and 0.5 parts by weight of ultraviolet absorber, and equipped with a vent, a gear pump, and three cooling rolls. The resin composition is heated and softened in an extruder set at a temperature of 280 ° C., the film is extruded from a T die at an extrusion rate of 40 kg / hr, and the take-off speed is 0.8 m / min. While being taken, the film was cooled with three cooling rolls having different temperatures (roll temperatures: 120 ° C., 170 ° C., 180 ° C.) and cut into predetermined dimensions to produce a flat plate having a thickness of 2 mm.

The obtained flat plate was a colorless and transparent plate having a total light transmittance of 88% and a haze of 1%. The flat sheet had a sheet resistivity of 2.1 × 10 ¹² Ω, and the area resistivity after washing with water was 3.2 × 10 ¹² Ω. Moreover, the area resistivity after a light resistance test was 8.3 * 10 < ¹² > (omega | ohm), and showed the outstanding light resistance. The evaluation results are shown in Table 1.

[Example 6]
A flat plate was produced in the same manner as in Example 1 except that 100% by mass of the polycarbonate resin, 2% by mass of the antistatic agent A, and 10% by mass of the ultraviolet absorber were used. The obtained flat plate had a total light transmittance of 88% and a haze of 1%, and was a colorless and transparent plate. The area resistivity of this flat plate was 4.8 × 10 ¹¹ Ω, and the area resistivity after washing with water was 5.2 × 10 ¹¹ Ω. The sheet resistivity after the light resistance test was 7.3 × 10 ¹¹ Ω and had excellent light resistance. The evaluation results are shown in Table 1.

[Example 7]
A flat plate having surface layers on both sides of the base sheet was manufactured using a multilayer sheet extrusion apparatus (feed block multilayer (2 types, 3 layers) multilayer sheet “SHT50”, manufactured by Hitachi Zosen). Polycarbonate resin is used as the base material, and the surface layer is prepared by dry blending 100% by weight of polycarbonate resin, 3% by weight of antistatic agent A and 5% by weight of UV absorber. Each is supplied to the raw material supply port, softened in an extruder at a temperature of 280 ° C., and sent to a T die so that a surface layer of 30 μm thickness is formed on both surfaces of a substrate made of polycarbonate resin, and the extrusion rate is 200 kg / hr. While extruding the film at a take-off speed of 0.8 m / min, the film is cooled with three cooling rolls having different temperatures (roll temperatures: 140 ° C., 150 ° C., 180 ° C.), cut into predetermined dimensions, A flat plate having a thickness of 2 mm was produced.

The obtained flat plate had a total light transmittance of 88% and a haze of 1%, and was a colorless and transparent plate. The area resistivity of this flat plate was 1.8 × 10 ¹² Ω, and the area resistivity after washing with water was 2.2 × 10 ¹² Ω. The area resistivity after the light resistance test was 6.3 × 10 ¹² Ω, which showed excellent light resistance. The evaluation results are shown in Table 1.

[Example 8]
100% by weight of polycarbonate resin, 2% by weight of antistatic agent A, 2% by weight of ultraviolet absorber, 0.5% by weight of silica particles ("Seahoster KE-P150 (trade name), manufactured by Nippon Shokubai Co., Ltd.), antioxidant (" Except for using 0.05% by mass of Irganox 2215 (trade name) (made by Ciba Specialty Chemicals) and 30 ppm of optical brightener (“Nikka Flow OB (trade name)”, made by Nippon Chemical Industry Co., Ltd.) A flat plate was obtained in the same manner as in Example 5.

The obtained flat plate had a total light transmittance of 67%, a haze of 94%, and a luminance of 3900 cd / m ² . This flat plate had a sheet resistivity of 3.1 × 10 ¹² Ω, and a sheet resistivity after washing with water of 4.2 × 10 ¹² Ω, which could be suitably used as a light diffusing plate. Moreover, the area resistivity after a light resistance test was 8.9 * 10 < ¹² > (omega | ohm), and showed the outstanding light resistance.

[Example 9]
Except for using 100% by weight of polycarbonate resin, 3% by weight of antistatic agent A, 2% by weight of UV absorber, 0.5% by weight of silica particles, 0.05% by weight of antioxidant and 30 ppm of fluorescent brightening agent. A flat plate was obtained in the same manner as in Example 5.

The obtained flat plate had a total light transmittance of 68%, a haze of 95%, and a luminance of 3950 cd / m ² and was suitable as a light diffusing plate. The plate has a sheet resistivity of 2.1 × 10 ¹² Ω and a sheet resistivity after washing of 3.2 × 10 ¹² Ω, which is considered to have permanent antistatic performance. Further, the sheet resistivity after the light resistance test was 8.3 × 10 ¹² Ω, and the light resistance was excellent.

[Comparative Example 1]
A flat plate was produced in the same manner as in Example 1 using polycarbonate resin as a raw material (injection molding). The obtained flat plate was a colorless and transparent plate having a total light transmittance of 89% and a haze of 1%. The sheet has a sheet resistivity of 5.3 × 10 ¹⁶ Ω.

[Comparative Example 2]
A method similar to that of Example 1 was dry blended with 100% by weight of polycarbonate resin and 1% by weight of antistatic agent B (“Irgastat P18” (trade name), manufactured by Ciba Specialty Chemicals, polyamide antistatic agent). A flat plate was manufactured. The resulting flat plate was colored due to decomposition of the polycarbonate, and the appearance was unusable for use as a product, so various characteristics were not evaluated.

[Comparative Example 3]
100% by mass of polycarbonate resin and 4% by mass of antistatic agent C (“ionic liquid T” (trade name), manufactured by Nisshinbo Co., Ltd., aliphatic quaternary ammonium salt) were dry blended, and the same as in Example 1 The flat plate was manufactured by the method.

The obtained flat plate was a transparent flat plate having a total light transmittance of 88% and a haze of 1%. The sheet had an area resistivity of 1.1 × 10 ¹² Ω and excellent initial antistatic performance, but the area resistivity after washing was lowered to 4.0 × 10 ¹⁵ Ω.

  In the column of optical material evaluation in Tables 1 and 2, “A” means evaluation as a transparent material, and “B” means evaluation as a light diffusion material.

  If the polycarbonate resin composition of the present invention is used, a molded product having an excellent antistatic effect in addition to the properties unique to the polycarbonate resin such as impact resistance, transparency, heat resistance and cold resistance can be obtained. Accordingly, the molded product made of the polycarbonate resin composition according to the present invention is less likely to cause troubles such as dust adhesion, malfunction, and electric shock due to electrification, so that the electrical, electronic equipment field, automobile field, machine field, medical field, etc. It can be used in many fields such as fields, and is particularly suitable for applications requiring transparency (for example, optical applications and electronic materials).

  In addition, the light diffusion plate of the present invention exhibits an excellent antistatic effect, and since this characteristic hardly deteriorates with time, it is difficult for the brightness to decrease due to dust adhesion, and the liquid crystal display device This is suitable for improving the display image quality.

Claims (7)

  A polycarbonate resin composition comprising a polycarbonate resin and a boric acid ester of a polyhydric alcohol fatty acid ester and / or a salt thereof.   Furthermore, the polycarbonate resin composition of Claim 1 which contains a ultraviolet absorber.   The polycarbonate resin composition according to claim 1 or 2, further comprising fine particles.   A molded article obtained from the polycarbonate resin composition according to any one of claims 1 to 3. A base sheet, and a multilayer sheet having a surface layer on at least one side of the base sheet,
The said surface layer is obtained from the resin composition in any one of Claims 1-3, The multilayer sheet characterized by the above-mentioned.   The molded article according to claim 4, which is used as a light diffusion plate.   The multilayer sheet according to claim 5, which is used as a light diffusing plate.