JP2010037380A - Aromatic polycarbonate resin composition for light guide plate and light guide plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition giving a light guide plate combining transparency and strength without discoloring even when molded into a thin light guide plate using an aromatic polycarbonate resin composition. <P>SOLUTION: This aromatic polycarbonate resin composition for a light guide plate contains 0.01-0.3 pts.wt of a glycerin monoester type mold release agent based on 100 pts.wt of an aromatic polycarbonate resin wherein viscosity-average molecular weight is 1.0×10<SP>4</SP>to 1.5×10<SP>4</SP>, the content of the low molecular weight component with molecular weight of not more than 1,000 is 1.5 wt.% or less, total nitrogen content is 15 ppm or less, the Cl content is 100 ppm or less, and an amount of OH terminal group is 0.1-30 eq/ton. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an aromatic polycarbonate resin composition for a light guide plate and a light guide plate.

  In order to meet the demands for thinning, lightening, power saving, and high definition, liquid crystal display devices used in personal computers, mobile phones, PDA (Personal Digital Assistant) car navigation systems, portable game machines, etc. A planar light source device is incorporated. The surface light source device has a wedge-shaped cross-section light guide plate having a uniform inclined surface and a flat plate shape for the purpose of uniformly and efficiently guiding incident light to the liquid crystal display side. A light guide plate is provided.

  Conventionally, the light guide plate has been molded from a resin material such as polymethylmethacrylate (PMMA). Recently, however, a display device that displays a clearer image has been demanded, and the temperature inside the device is increased by heat generated in the vicinity of the light source. Therefore, it is being replaced with an aromatic polycarbonate resin material having higher heat resistance.

  In addition, with the trend toward thin and large display devices such as televisions and personal computers, the tendency for thin and large light guide plates and their peripheral components has become even stronger. For example, the thickness of a liquid crystal display device used in a cellular phone or the like is currently about 3 mm, and the thickness of a light guide plate incorporated in the liquid crystal display device is about 0.7 mm at its thinnest. However, in the recent trend of further reducing the thickness of the liquid crystal display device, the thickness of the light guide plate is required to be less than 0.7 mm.

  In order to obtain a thin and large light guide plate, molding at a temperature higher than the conventional molding temperature is required, so it not only has excellent fluidity and transferability, but also discoloration and adhesion of dirt to the mold, etc. In addition, there is a need for a resin material that is excellent in melting heat stability and releasability.

  As a resin material excellent in fluidity and mechanical strength, an aromatic polycarbonate resin having a tert-octylphenoxy group as a terminal group is known (Patent Document 1). In addition, an aromatic polycarbonate resin having a long-chain alkylphenoxy group as a terminal group (Patent Document 2), a polycarbonate resin composition (Patent Document 3) comprising a copolyestercarbonate having an aliphatic segment and an aromatic polycarbonate has been proposed. .

  However, the thickness of the light guide plate in the above proposal is about 3 mm, and as a result of attempting to manufacture a light guide plate having a thickness of less than 0.7 mm by the injection molding method based on the proposed technique, a light guide plate having a desired thickness is manufactured However, sufficient fluidity could not be secured, and the cavity could not be completely filled with the molten thermoplastic resin. Further, in any of the proposals, only a light guide plate having poor practical value and poor heat stability and releasability can be obtained.

  On the other hand, an aromatic polycarbonate resin composition for a light guide plate in which a specific molecular weight and a ratio Mw / Mn between a weight average molecular weight and a number average molecular weight are defined has been proposed (Patent Document 4). However, in general technology, in order to satisfy a certain range of molecular weight and Mw / Mn, it is necessary to use a catalyst such as triethylamine particularly during polymerization of the polymer. There was a problem that significant yellowing occurred during processing.

JP 2001-208917 A JP 2001-208918 A JP 2001-215336 A JP 2007-204737 A

  An object of the present invention is a light guide plate made of an aromatic polycarbonate resin having high heat resistance, which can be molded even if the light guide plate is thin, has no dirt adherence to the mold, and is also suitable for molding processing. An object of the present invention is to provide an aromatic polycarbonate resin composition for a light guide plate that does not cause yellowing.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have determined that even an aromatic polycarbonate resin having a molecular weight capable of forming a thin-walled molded product has an OH terminal group content, a Cl content, and a low molecular weight. The inventors have found that a light guide plate having no discoloration such as yellowing can be obtained by adjusting the components and the total nitrogen content to predetermined amounts, and have reached the present invention.

That is, according to the present invention,
1. Viscosity average molecular weight is 1.0 × 10 ^{4 to} 1.5 × 10 ⁴ , low molecular weight component content of molecular weight 1000 or less is 1.5 wt% or less, total nitrogen content is 15 ppm or less, Cl content is 100 ppm or less, Aromatics for light guide plates containing 0.01 to 0.3 parts by weight of a glycerin monoester type release agent with respect to 100 parts by weight of an aromatic polycarbonate resin having an OH end group amount of 0.1 to 30 eq / ton Polycarbonate resin composition,
2. 2. The aromatic polycarbonate resin composition for a light guide plate according to item 1 above, wherein the main component of the glycerin monoester type release agent is a monoester of behenic acid,
3. The aromatic polycarbonate resin composition for a light guide plate according to the preceding item 1, wherein the viscosity average molecular weight of the aromatic polycarbonate resin is 1.0 × 10 ^{4 to} 1.3 × 10 ⁴ ,
4). The aromatic polycarbonate resin composition for a light guide plate according to item 1, wherein the aromatic polycarbonate resin is an aromatic polycarbonate resin that is polymerized by a non-catalytic interfacial polycondensation method and subjected to low molecular weight component extraction treatment with acetone after polymerization,
5. 5. a light guide plate having a minimum thickness of 0.4 mm or less formed from the resin composition according to item 1; 6. The light guide plate according to 5 above, wherein the molding method is injection press molding in which resin is compressed in a mold.
Is provided.

Hereinafter, the present invention will be described in detail.
An aromatic polycarbonate resin (hereinafter sometimes simply referred to as “polycarbonate”) is obtained by reacting a dihydric phenol and a carbonate precursor. The reaction may be performed by interfacial polycondensation, melt transesterification, or the like. Method, solid phase transesterification method of carbonate prepolymer, ring-opening polymerization method of cyclic carbonate compound, and the like. Among these, the interfacial polycondensation method is most preferable.

  Specific examples of the dihydric phenol include hydroquinone, resorcinol, 4,4′-biphenol, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane (commonly referred to as “bisphenol”). A ″), 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxyphenyl) pentane, 4, 4 ′-(p-phenylenediisopropylidene) diphenol, 4,4 ′-(m-phenylenediisopropylidene) Phenol, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, bis (4-hydroxyphenyl) oxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfoxide, bis (4- Hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ester, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, bis (3,5-dibromo- 4-hydroxyphenyl) sulfone, bis (4-hydroxy-3-methylphenyl) sulfide, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, etc. Is mentioned. Among these, bis (4-hydroxyphenyl) alkane, particularly bisphenol A (hereinafter sometimes abbreviated as “BPA”) is preferable, and the ratio thereof is preferably 50 to 100 mol% in the dihydric phenol component.

In the present invention, in addition to the bisphenol A-based polycarbonate, a special polycarbonate produced using other dihydric phenols can be used as the A component.
For example, as part or all of the dihydric phenol component, 4,4 ′-(m-phenylenediisopropylidene) diphenol (hereinafter sometimes abbreviated as “BPM”), 1,1-bis (4-hydroxy Phenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (hereinafter sometimes abbreviated as “Bis-TMC”), 9,9-bis (4-hydroxyphenyl) Polycarbonate (homopolymer or copolymer) using fluorene and 9,9-bis (4-hydroxy-3-methylphenyl) fluorene (hereinafter sometimes abbreviated as “BCF”) has dimensions due to water absorption. It is suitable for a light guide plate that requires particularly strict changes and morphological stability.

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

  In producing a polycarbonate from such a dihydric phenol and a carbonate precursor by an interfacial polymerization method, a catalyst, a terminal terminator, and an antioxidant for preventing the dihydric phenol from being oxidized as necessary. Etc. may be used. The polycarbonate may be a branched polycarbonate copolymerized with a trifunctional or higher polyfunctional aromatic compound. Examples of the trifunctional or higher polyfunctional aromatic compound used here include 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1,1-tris (3,5-dimethyl-4-hydroxy). Phenyl) ethane and the like.

  The polycarbonate is a polyester carbonate obtained by copolymerizing an aromatic or aliphatic (including alicyclic) difunctional carboxylic acid, a copolymer polycarbonate obtained by copolymerizing a bifunctional alcohol (including alicyclic), and the like. The polyester carbonate which copolymerized both bifunctional carboxylic acid and bifunctional alcohol may be sufficient. Moreover, the mixture which blended 2 or more types of the obtained polycarbonate may be used.

  In the polycarbonate polymerization reaction, the reaction by the interfacial polycondensation method is usually a reaction between a dihydric phenol and phosgene, and is carried out in the presence of an acid binder and an organic solvent. As the acid binder, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is preferably used. As the organic solvent, halogenated hydrocarbons such as methylene chloride and chlorobenzene are preferably used. In order to promote the reaction, a catalyst such as a tertiary amine such as triethylamine, tetra-n-butylammonium bromide, tetra-n-butylphosphonium bromide, a quaternary ammonium compound, or a quaternary phosphonium compound can be used. In the present invention, it is premised that a trace amount of nitrogen is not increased by using a catalyst. Therefore, a polymerization reaction by a non-catalytic method is preferable. At that time, the reaction temperature is usually 0 to 40 ° C., the reaction time is preferably about 10 minutes to 5 hours, and the pH during the reaction is preferably maintained at 9 or more.

  In such a polymerization reaction, a terminal terminator is usually used. Monofunctional phenols can be used as such end terminators. As monofunctional phenols, monofunctional phenols such as phenol, p-tert-butylphenol, and p-cumylphenol are preferably used.

The organic solvent solution of the polycarbonate resin obtained by the interfacial polycondensation method is usually washed with water. This washing step is preferably performed with water having an electric conductivity of 10 μS / cm or less, such as ion-exchanged water, and more preferably 1 μS / cm or less. The organic solvent solution and water are mixed and stirred, and then allowed to stand. Alternatively, the organic solvent solution phase and the aqueous phase are separated using a centrifuge or the like, and the organic solvent solution phase is removed repeatedly to remove water-soluble impurities. By washing with high-purity water, water-soluble impurities are efficiently removed, and the resulting polycarbonate resin has a good hue.
In addition, the organic solvent solution of the polycarbonate resin described above is preferably subjected to acid cleaning or alkali cleaning in order to remove impurities.

The organic solvent solution is preferably removed from foreign substances that are insoluble impurities. As a method for removing the foreign matter, a method of filtering or a method of treating with a centrifuge is preferably employed.
The organic solvent solution that has been washed with water is then subjected to an operation of removing the solvent to obtain a polycarbonate resin powder.

  As a method (granulation process) for obtaining a polycarbonate resin granule, since operation and post-treatment are simple, stirring is performed in a granulation apparatus in which polycarbonate granule and hot water (about 65 to 90 ° C.) are present. However, a method of producing a slurry by continuously supplying an organic solvent solution of polycarbonate and evaporating the solvent is used. As the granulator, a mixer such as a stirring tank or a kneader is used. The produced slurry is continuously discharged from the upper or lower part of the granulator.

  The discharged slurry can then be subjected to hot water treatment. In the hydrothermal treatment step, the slurry is supplied to a hydrothermal treatment container containing hot water at 90 to 100 ° C., or after being supplied, the water temperature is changed to 90 to 100 ° C. by blowing steam or the like. The organic solvent contained is removed.

  The slurry discharged in the granulation step or the slurry after the hot water treatment is preferably filtered, centrifuged, etc. to remove water and organic solvent, and then dried to give polycarbonate resin granules (powder or flakes) Can be obtained.

  The dryer may be a conduction heating method or a hot air heating method, and the polycarbonate resin particles may be allowed to stand, be transferred, or stirred. Among these, a grooved or cylindrical dryer in which the polycarbonate resin particles are stirred by a conductive heating method is preferable, and a grooved dryer is particularly preferable. The drying temperature is preferably in the range of 130 ° C to 150 ° C.

  The polycarbonate resin granules obtained as described above usually contain impurities such as oligomers and monomers. In the present invention, the content of low molecular weight components having a molecular weight of 1000 or less is 1.5% by weight or less, preferably 1.3% by weight or less, and most preferably 1.1% by weight or less.

  As a method for removing the low molecular weight component, acetone treatment may be mentioned. The method described in JP-A-4-306227 is preferably used, and this method is a method for removing low molecular weight components easily and inexpensively.

When the viscosity average molecular weight of the polycarbonate resin of the present invention is less than 1.0 × 10 ⁴ , strength and the like are lowered, and when it exceeds 1.5 × 10 ⁴ , molding process characteristics are lowered. The range of 0 × 10 ^{4 to} 1.5 × 10 ⁴ is preferable, the range of 1.0 × 10 ^{4 to} 1.3 × 10 ⁴ is more preferable, and the range of 1.2 × 10 ^{4 to} 1.3 × 10 ⁴ is preferable. Is more preferable. Moreover, it is also possible to mix the polycarbonate whose viscosity average molecular weight is outside the above range within the range where the moldability and the like are maintained. For example, a small amount of a high molecular weight polycarbonate component having a viscosity average molecular weight exceeding 5.0 × 10 ⁴ can be blended. In this case, the viscosity average molecular weight of the polycarbonate resin mixture obtained by mixing polycarbonate resins having different viscosity average molecular weights may be in the above range.

The viscosity average molecular weight referred to in the present invention is first determined by using an Ostwald viscometer from a solution in which 0.7 g of polycarbonate resin is dissolved in 100 ml of methylene chloride at 20 ° C., with a specific viscosity (η _SP ) calculated by the following formula:
Specific viscosity (η _SP ) = (t−t ₀ ) / t ₀
[T ₀ is methylene chloride falling seconds, t is sample solution falling seconds]
The viscosity average molecular weight M is calculated from the determined specific viscosity (η _SP ) by the following formula.
η _SP /c=[η]+0.45×[η] ² c (where [η] is the intrinsic viscosity)
[Η] = 1.23 × 10 ⁻⁴ M ^0.83
c = 0.7

In addition, when measuring the viscosity average molecular weight of the polycarbonate resin of this invention, it can carry out in the following way. That is, the polycarbonate resin is dissolved in 20 to 30 times the weight of methylene chloride, and the soluble component is collected by celite filtration, and then the solution is removed and dried sufficiently to obtain a solid component soluble in methylene chloride. A specific viscosity (η _SP ) at 20 ° C. is determined from a solution obtained by dissolving 0.7 g of the solid in 100 ml of methylene chloride using an Ostwald viscometer, and the viscosity average molecular weight M is calculated by the above formula.

  The Cl content in the aromatic polycarbonate resin can be adjusted by the following method. In the case of the interfacial polycondensation method described above, the Cl content can be effectively reduced by drying strengthening in the granulation step. It is also effective to replace the solvent itself with a solvent containing no Cl such as heptane in the granulation step. Further, a method of strengthening the vacuum vent in the step of melting and pelletizing is also effective. Furthermore, it is possible to reduce the Cl content by injecting water or a poor solvent of a polycarbonate resin such as heptane at the time of melt extrusion and azeotropically using a vacuum vent. On the other hand, the aromatic polycarbonate resin polymerized by the melt transesterification method is useful because it does not contain Cl in the first place.

  The Cl content in the aromatic polycarbonate resin is 100 ppm or less, preferably 0.1 to 100 ppm, more preferably 0.1 to 70 ppm, and further preferably 0.1 to 50 ppm.

  The Cl content in the aromatic polycarbonate resin is measured by a combustion method. After the sample is weighed, it is burned in a mixed gas stream of argon and oxygen, and determined by the amount of electrification and movement of the silver electrode. The measurement was performed with Mitsubishi Chemical Corporation TOX-2100H.

  The amount of OH end groups of the aromatic polycarbonate resin can be adjusted by the following method. In the case of the interfacial polycondensation method, the amount of OH end groups is adjusted depending on the use of the catalyst, the amount of the end terminator added, and the addition time. It is also effective to perform the polymerization reaction in a stationary state. In the melt transesterification method, the amount of OH end groups can be reduced by making the abundance ratio of dihydric phenol and carbonate ester to carbonate ester.

  The amount of OH end groups of the aromatic polycarbonate resin is 0.1 to 30 eq / ton, preferably 0.1 to 25 eq / ton, and more preferably 0.1 to 20 eq / ton. In addition, the amount of OH end groups of the aromatic polycarbonate resin is measured by an NMR method.

  The total amount of nitrogen in the aromatic polycarbonate resin can be adjusted by the presence or absence of a catalyst during polymerization and the amount used. In the present invention, an aromatic polycarbonate resin is preferably polymerized by an interfacial polycondensation method without a catalyst.

  The total nitrogen content in the aromatic polycarbonate resin is 15 ppm or less, preferably 0.1 to 15 ppm, more preferably 0.1 to 13 ppm, and still more preferably 0.1 to 10 ppm. The total nitrogen content in the aromatic polycarbonate resin is measured by a chemiluminescence method.

  The glycerin monoester used as a release agent in the present invention is mainly composed of a monoester of glycerin and a fatty acid, and suitable fatty acids include stearic acid, palmitic acid, behenic acid, arachidic acid, montanic acid, lauric acid and the like. Examples include saturated fatty acids, unsaturated fatty acids such as oleic acid, linoleic acid, and sorbic acid, stearic acid, behenic acid, and palmitic acid are particularly preferable, and behenic acid is particularly preferable. Those synthesized from natural fatty acids are preferred, most of which are mixtures.

  The content of glycerin monoester is 0.01 to 0.3 parts by weight, preferably 0.02 to 0.2 parts by weight, more preferably 0.025 to 0 parts per 100 parts by weight of the aromatic polycarbonate resin. 15 parts by weight. When the content is too small, good releasability cannot be obtained, and when the content is too large, discoloration of the molded product is deteriorated.

  The mold release agent can be used in combination with other mold release agents known to those skilled in the art, but even when used in combination, the glycerin monoester content is 0.01 to 0.3 parts by weight. Preferably it is a component.

  The polycarbonate resin of the present invention includes a heat stabilizer, an ultraviolet absorber, a bluing agent, an antistatic agent, a flame retardant, a heat ray shielding agent, and a fluorescent dye (including a fluorescent whitening agent) as long as the object of the present invention is not impaired. , Pigments, light diffusing agents, reinforcing fillers, other resins, elastomers, and the like can be blended.

  Examples of the heat stabilizer include a phosphorus heat stabilizer, a sulfur heat stabilizer, and a hindered phenol heat stabilizer.

  Examples of the phosphorous heat stabilizer include phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid and esters thereof. Specifically, triphenyl phosphite, tris (nonylphenyl) phosphite, tris ( 2,4-di-tert-butylphenyl) phosphite, tris (2,6-di-tert-butylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite Phyto, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) penta Erisrito Diphosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol di Phosphite, distearyl pentaerythritol diphosphite, tributyl phosphate, triethyl phosphate, trimethyl phosphate, triphenyl phosphate, diphenyl monoorthoxenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, dimethyl benzenephosphonate, diethyl benzenephosphonate, Dipropyl benzenephosphonate, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylenediphosphonai Tetrakis (2,4-di-t-butylphenyl) -4,3′-biphenylenediphosphonite, tetrakis (2,4-di-t-butylphenyl) -3,3′-biphenylenediphosphonite, bis And (2,4-di-tert-butylphenyl) -4-phenyl-phenylphosphonite and bis (2,4-di-tert-butylphenyl) -3-phenyl-phenylphosphonite.

  Among them, tris (2,4-di-tert-butylphenyl) phosphite, tris (2,6-di-tert-butylphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl) -4 , 4′-biphenylenediphosphonite, tetrakis (2,4-di-t-butylphenyl) -4,3′-biphenylenediphosphonite, tetrakis (2,4-di-t-butylphenyl) -3,3 '-Biphenylenediphosphonite, bis (2,4-di-tert-butylphenyl) -4-phenyl-phenylphosphonite and bis (2,4-di-tert-butylphenyl) -3-phenyl-phenylphosphonite And particularly preferably tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite is used. It is.

  As content of the phosphorus-type heat stabilizer in aromatic polycarbonate resin, 0.001-0.2 weight part is preferable with respect to 100 weight part of aromatic polycarbonate resin.

  As the sulfur-based heat stabilizer, pentaerythritol-tetrakis (3-laurylthiopropionate), pentaerythritol-tetrakis (3-myristylthiopropionate), pentaerythritol-tetrakis (3-stearylthiopropionate), Examples include dilauryl-3, 3′-thiodipropionate, dimyristyl-3, 3′-thiodipropionate, distearyl-3, 3′-thiodipropionate, and pentaerythritol-tetrakis (3- Lauryl thiopropionate), pentaerythritol-tetrakis (3-myristyl thiopropionate), dilauryl-3, 3'-thiodipropionate, dimyristyl-3, 3'-thiodipropionate. Particularly preferred is pentaerythritol-tetrakis (3-laurylthiopropionate). The thioether compounds are commercially available from Sumitomo Chemical Co., Ltd. as Sumilizer TP-D (trade name), Sumilizer TPM (trade name), and the like, and can be easily used.

  As content of the sulfur type heat stabilizer in aromatic polycarbonate resin, 0.001-0.2 weight part is preferable with respect to 100 weight part of aromatic polycarbonate resin.

  Examples of the hindered phenol heat stabilizer include triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3 , 5-di-tert-butyl-4-hydroxyphenyl) propionate], pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3 5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, N, N-hexamethylene bis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide) 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate and 3,9-bis {1,1- And dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2,4,8,10-tetraoxaspiro (5,5) undecane. Octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate is particularly preferably used.

  As content of the hindered phenol type heat stabilizer in aromatic polycarbonate resin, 0.001-0.1 weight part is preferable with respect to 100 weight part of aromatic polycarbonate resin.

  As the UV absorber, at least one UV absorber selected from the group consisting of benzotriazole UV absorbers, benzophenone UV absorbers, triazine UV absorbers, cyclic imino ester UV absorbers, and cyanoacrylates Is preferred.

  Examples of the benzotriazole ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy- 3,5-dicumylphenyl) phenylbenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2,2'-methylenebis [4- (1,1 , 3,3-tetramethylbutyl) -6- (2N-benzotriazol-2-yl) phenol], 2- (2-hydroxy-3,5-di-tert-butylphenyl) benzotriazole, 2- ( 2-hydroxy-3,5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy 3,5-di-tert-amylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-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 these may be used alone or in combination of two or more. Can be used in a mixture.

  Preferably, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-3,5-dicumyl) Phenyl) phenylbenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2,2′-methylenebis [4- (1,1,3,3-tetra Methylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimidomethyl) -5-methylphenyl] benzotriazole And more preferably 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2,2 ′ Methylenebis [4- (1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl) phenol].

  Examples of benzophenone-based ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 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- Methoxyphenyl) meta , 2-hydroxy -4-n-dodecyloxy benzoin phenone, 2-hydroxy-4-methoxy-2'-carboxy benzophenone.

  Examples of the triazine ultraviolet absorber include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, 2- (4,6-bis ( And 2.4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-[(octyl) oxy] -phenol.

  Examples of cyclic imino ester UV absorbers include 2,2′-bis (3,1-benzoxazin-4-one) and 2,2′-p-phenylenebis (3,1-benzoxazin-4-one). 2,2′-m-phenylenebis (3,1-benzoxazin-4-one), 2,2 ′-(4,4′-diphenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2,6-naphthalene) bis (3,1-benzoxazin-4-one), 2,2 ′-(1,5-naphthalene) bis (3,1-benzoxazin-4-one) ), 2,2 ′-(2-methyl-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2-nitro-p-phenylene) bis (3,1- Benzoxazin-4-one) and 2,2 ′-(2-chloro-p-ph) Ylene) bis (3,1-benzoxazin-4-one) is illustrated. Among them, 2,2′-p-phenylenebis (3,1-benzoxazin-4-one), 2,2 ′-(4,4′-diphenylene) bis (3,1-benzoxazin-4-one) And 2,2 ′-(2,6-naphthalene) bis (3,1-benzoxazin-4-one) are preferred, especially 2,2′-p-phenylenebis (3,1-benzoxazine-4 -On) is preferred. Such a compound is commercially available from Takemoto Yushi Co., Ltd. as CEi-P (trade name) and can be easily used.

  As the cyanoacrylate ultraviolet absorber, 1,3-bis-[(2′-cyano-3 ′, 3′-diphenylacryloyl) oxy] -2,2-bis [(2-cyano-3,3-diphenyl) Examples include acryloyl) oxy] methyl) propane and 1,3-bis-[(2-cyano-3,3-diphenylacryloyl) oxy] benzene.

  The blending amount of the ultraviolet absorber is preferably 0.01 to 3.0 parts by weight, more preferably 0.02 to 1.0 parts by weight, further preferably 100 parts by weight of the aromatic polycarbonate resin. Is 0.05 to 0.8 part by weight. If it is the range of this compounding quantity, it is possible to provide sufficient weather resistance to a polycarbonate resin molded product according to a use.

Examples of the bluing agent include Macrolex Violet B and Macrolex Blue RR manufactured by Bayer and polysynthremble-RLS manufactured by Clariant. The bluing agent is effective for eliminating the yellow color of the polycarbonate resin particles. In particular, in the case of polycarbonate resin granules with weather resistance, a certain amount of UV absorber is blended, so there is a reality that the polycarbonate resin molded product tends to be yellowish due to the "action and color of the UV absorber". In particular, the blending of the bluing agent is very effective for imparting a natural transparency to the light guide plate.
The blending amount of the bluing agent is preferably 0.05 to 1.5 ppm, more preferably 0.1 to 1.2 ppm with respect to the aromatic polycarbonate resin.

The light guide plate of the present invention is preferably manufactured by injection press molding in which resin is injected into a mold and then pressed and molded in the mold.
The light guide plate formed from the resin composition of the present invention preferably has a minimum thickness of 0.4 mm or less. When the minimum thickness is 0.4 mm or less, the effect of the present invention is easily exhibited.

  The resin composition for a light guide plate of the present invention is excellent in heat resistance and moldability, does not cause discoloration even with a thin molded product, and is excellent in transparency and strength. is there.

  The form of the present invention considered to be the best by the present inventors is a collection of the preferable ranges of the above requirements. For example, typical examples are described in the following examples.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to these. In addition, the measurement of the various characteristics in an Example was based on the following method.

(1) Cl content in aromatic polycarbonate resin Aromatic polycarbonate resin pellets and powder were weighed, burned in a mixed gas stream of argon and oxygen, and titrated with the amount of electrification and movement of the silver electrode. The measurement was performed with Mitsubishi Chemical Corporation TOX-2100H.

(2) Amount of OH terminal group of aromatic polycarbonate resin 40 mg each of aromatic polycarbonate resin pellets and powder are dissolved in 1 ml of deuterated chloroform and charged into an NMR sample tube having an inner diameter of 5 mm so that the liquid level is 40 mm. The sample for NMR measurement was prepared. This was measured by non-decoupling and 512 integrations using 1H-NMR using FT-NMR AL-400 manufactured by JEOL Ltd. The integrated values of peaks at chemical shifts of 6.66 to 6.73 ppm and 6.93 to 7.00 ppm were obtained from the obtained NMR spectrum chart, and the OH end group amount (eq / ton) was calculated from the following formula. In addition, the chart used for the measurement and each peak are shown in FIG.
OH end group amount (eq / ton) = (A / 2) / (B / (C × 2/100)) × (1000000 / D)
A: integrated value of peak of 6.66 to 6.73 ppm B: integrated value of peak of 6.93 to 7.00 ppm C: abundance of carbon isotope 13C (1.18%)
D: Mass number per unit of PC (bisphenol A polycarbonate: 254)

(3) Measurement of low molecular weight component content It calculated | required by the area ratio (%) in the GPC analysis using the column which arranged TOHSOHXL-2000 and HXL-3000 in series.

(4) Measurement of total nitrogen content Using a trace total nitrogen analyzer TN-110 manufactured by Mitsubishi Chemical Corporation, the total nitrogen content in 20 mg was measured.

(5) Evaluation of Hue (Color Difference ΔE) A 2 mm thick square plate was molded from the pellets by using a Japanese-made Tsunasho injection molding machine J85-ELIII at a cylinder temperature of 370 ° C., a mold temperature of 80 ° C., and a 1-minute cycle. After 20 shots were continuously formed, the resin was allowed to stay in the cylinder of the injection molding machine for 10 minutes to form a 2 mm thick square plate after the stay. The hue (L, a, b) of the flat plate before and after the residence was measured by a C light source reflection method using a color difference meter SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd., and the color difference ΔE was determined by the following formula.
ΔE = {(L−L ′) ² + (aa ′) ² + (b−b ′) ² } ^1/2
Hue of “measurement flat plate before residence”: L, a, b
Hue of “plate for measurement after residence”: L ′, a ′, b ′

(6) Molding of light guide plate A simulated light guide plate having a thickness of 0.4 mm and a 70 mm × 40 mm square was prepared using pellets. Molding was performed from injection molding using a molding temperature of 360 ° C. The injection pressure was set to 250 MPa, and the samples that were not filled were molded by increasing the injection temperature to 385 ° C. every 5 ° C., and those that were not filled even at 385 ° C. were made unmoldable. About what was able to shape | mold, it was confirmed whether there was yellowing in a molded article.
1: No problem
2: Yellowing occurred
3: Molding is impossible

(7) Evaluation of Light Guide Plate A simulated light guide plate having a thickness of 0.4 mm and a 70 mm × 40 mm square was prepared using pellets that could be formed in the light guide plate molding (6). For the molding, injection press molding was used, the mold was opened in advance to a thickness of 2 mm, the resin was injected, and the press was performed to 0.4 mm. The produced light guide plate was incorporated into a Docomo, N906iμ liquid crystal unit, and one-segment broadcasting was broadcast for 1000 hours in an atmosphere at 40 ° C. After the test, the simulated light guide plate was taken out and checked for deformation or discoloration.
1: No problem
2: Yellowing occurred
3: Deformation occurs

[Synthesis Example 1]
A reactor equipped with a thermometer, a stirrer and a reflux condenser was charged with 219.4 parts of ion-exchanged water and 40.2 parts of a 48% aqueous sodium hydroxide solution, and 2,2-bis (4-hydroxyphenyl) propane 57. After 5 parts and 0.12 part of hydrosulfite were added and dissolved in 25 minutes, 181 parts of methylene chloride was added over 5 minutes, and 27.8 parts of phosgene was blown in at a temperature of 15 to 25 ° C. for 40 minutes. It is. After completion of phosgene blowing, 2,2-bis (4-hydroxyphenyl) propane was added to 7.2 parts of 48% aqueous sodium hydroxide and 2.04 parts of p-tert-butylphenol and 1 part of 7.4% aqueous sodium hydroxide. 0.65 part of a solution in which 0.20 part was dissolved was added, and after emulsification with a homomixer, stirring was stopped and the reaction was terminated by allowing to stand at 28 to 33 ° C. for 2.5 hours. After completion of the reaction, 200 parts of methylene chloride was added to and mixed with the product, the stirring was stopped, and the aqueous phase and the organic phase were separated to obtain an organic solvent solution having a polycarbonate resin concentration of 15% by weight. After adding 200 parts of ion-exchanged water to this organic solvent solution and stirring and mixing, stirring was stopped and the aqueous phase and the organic phase were separated. This operation was repeated (four times) until the conductivity of the aqueous phase was almost the same as that of ion-exchanged water. The obtained purified polycarbonate resin solution was filtered with a 1 μm filter made of SUS304.

  Next, 100 L of ion-exchanged water is introduced into a 1000 L kneader made of SUS316L, and the methylene chloride is evaporated at a water temperature of 42 ° C. The powder and the mixture of the powder and water were put into a hot water treatment tank of a hot water treatment process having a hot water treatment tank with a stirrer controlled at a water temperature of 95 ° C., and 25 parts of powder and water The mixture was stirred for 30 minutes at a mixing ratio of 75 parts. This mixture of powder and water was separated by a centrifugal separator to obtain a powder containing 0.5% by weight of methylene chloride and 45% by weight of water. Next, this granular material was continuously supplied at 50 kg / Hr (in terms of polycarbonate resin) to a SUS316L conductive heat receiving groove type biaxial stirring continuous dryer controlled at 140 ° C., and the condition of an average drying time of 6 hours And dried to obtain a powder particle having a viscosity average molecular weight of 15000 and a Cl content of 50 ppm. The obtained granular material was put into acetone, and after stirring for 30 minutes, the granular material slurry solution was taken out. After solid-liquid separation, it was dried in a nitrogen atmosphere at 140 ° C. for 4 hours, and extracted with acetone. Viscosity average molecular weight 15600, Cl A granular material (powder) having a content of 2.2 ppm was obtained.

[Synthesis Example 2]
Synthesis was performed in the same manner as in Synthesis Example 1 except that p-tert-butylphenol was changed to 3.10 parts, and viscosity average molecular weight 12500 extracted from acetone from a granular material having a viscosity average molecular weight of 11800 and a Cl content of 38 ppm, A granular material (powder) having a Cl content of 1.3 ppm was obtained.

[Synthesis Example 3]
A reactor equipped with a thermometer, a stirrer and a reflux condenser was charged with 219.4 parts of ion-exchanged water and 40.2 parts of a 48% aqueous sodium hydroxide solution, and 2,2-bis (4-hydroxyphenyl) propane 57. After 5 parts and 0.12 part of hydrosulfite were added and dissolved in 25 minutes, 181 parts of methylene chloride was added over 5 minutes, and 27.8 parts of phosgene was blown in at a temperature of 15 to 25 ° C. for 40 minutes. It is. After completion of the phosgene blowing, 2,2-bis (4-hydroxyphenyl) propane was added to 7.2 parts of 48% aqueous sodium hydroxide and 2.14 parts of p-tert-butylphenol and 1 part of 7.4% aqueous sodium hydroxide. 0.65 part of a solution in which 0.20 part was dissolved was added, and after emulsification with a homomixer, stirring was stopped. After 10 minutes after the stirring was stopped, the mixture was again stirred and emulsified, and then 0.06 part of triethylamine was added thereto, and the reaction was completed in 30 minutes at 28 to 33 ° C. After completion of the reaction, 200 parts of methylene chloride was added to and mixed with the product, the stirring was stopped, and the aqueous phase and the organic phase were separated to obtain an organic solvent solution having a polycarbonate resin concentration of 15% by weight. After adding 200 parts of ion-exchanged water to this organic solvent solution and stirring and mixing, stirring was stopped and the aqueous phase and the organic phase were separated. This operation was repeated (four times) until the conductivity of the aqueous phase was almost the same as that of ion-exchanged water. The obtained purified polycarbonate resin solution was filtered with a 1 μm filter made of SUS304.

  Next, 100 L of ion-exchanged water is introduced into a 1000 L kneader made of SUS316L, and the methylene chloride is evaporated at a water temperature of 42 ° C. The powder and the mixture of the powder and water were put into a hot water treatment tank of a hot water treatment process having a hot water treatment tank with a stirrer controlled at a water temperature of 95 ° C., and 25 parts of powder and water The mixture was stirred for 30 minutes at a mixing ratio of 75 parts. This mixture of powder and water was separated by a centrifugal separator to obtain a powder containing 0.5% by weight of methylene chloride and 45% by weight of water. Next, this granular material was continuously supplied at 50 kg / Hr (in terms of polycarbonate resin) to a SUS316L conductive heat receiving groove type biaxial stirring continuous dryer controlled at 140 ° C., and the condition of an average drying time of 6 hours Was dried to obtain a powder (powder) having a viscosity average molecular weight of 15000 and a Cl content of 52 ppm.

[Synthesis Example 4]
Synthesis was performed in the same manner as in Synthesis Example 3 except that p-tert-butylphenol was changed to 3.25 parts, and a powder (viscosity) having a viscosity average molecular weight of 11800 and a Cl content of 37 ppm was obtained.
The characteristics of the aromatic polycarbonate resin granules PC-1 to PC-4 synthesized in Synthesis Examples 1 to 4 are shown in Table 1.

[Examples 1-4, Comparative Examples 1-3]
The polycarbonate resin composition blended with each component shown in Table 2 was extruded at 300 ° C. with TEX-30α manufactured by Nippon Steel Works, and the strand was cut to obtain pellets. The obtained pellets were dried at 120 ° C. for 4 hours. The above various evaluations were performed using the obtained pellets. The results are shown in Table 2.

In addition, each component in Table 1 and Table 2 is as follows.
PC-1: Aromatic polycarbonate resin granules (powder) synthesized in Synthesis Example 1
PC-2: Aromatic polycarbonate resin granules (powder) synthesized in Synthesis Example 2
PC-3: Aromatic polycarbonate resin granules (powder) synthesized in Synthesis Example 3
PC-4: Aromatic polycarbonate resin granules (powder) synthesized in Synthesis Example 4
L1: Release agent; Riken vitamin S-100A (main component glycerin monostearate)
L2: Mold release agent; Riken vitamin B-100A (main component glycerin monobehenate)
A1: Phosphorus stabilizer; P-EPQ manufactured by Clariant Japan
H1: Brewing agent; Macrolex Violet B from Bayer

It is the figure which showed the 1H-NMR spectrum chart of the aromatic polycarbonate resin pellet.

Claims (6)

Viscosity average molecular weight is 1.0 × 10 ^{4 to} 1.5 × 10 ⁴ , low molecular weight component content of molecular weight 1000 or less is 1.5 wt% or less, total nitrogen content is 15 ppm or less, Cl content is 100 ppm or less, Aromatics for light guide plates containing 0.01 to 0.3 parts by weight of a glycerin monoester type release agent with respect to 100 parts by weight of an aromatic polycarbonate resin having an OH end group amount of 0.1 to 30 eq / ton Polycarbonate resin composition.   2. The aromatic polycarbonate resin composition for a light guide plate according to claim 1, wherein the main component of the release agent of the glycerin monoester type is a monoester of behenic acid. The aromatic polycarbonate resin composition for a light guide plate according to claim 1, wherein the aromatic polycarbonate resin has a viscosity average molecular weight of 1.0 × 10 ^{4 to} 1.3 × 10 ⁴ .   2. The aromatic polycarbonate resin composition for a light guide plate according to claim 1, wherein the aromatic polycarbonate resin is an aromatic polycarbonate resin that is polymerized by a non-catalytic interfacial polycondensation method and is subjected to low molecular weight component extraction treatment with acetone after polymerization.   A light guide plate having a minimum thickness of 0.4 mm or less formed from the resin composition according to claim 1.   The light guide plate according to claim 5, wherein the molding method is injection press molding in which a resin is compressed in a mold.

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