Polycarbonate resin composition and molded article thereof

Abstract

To provide a polycarbonate resin composition that has excellent light guiding properties and is less prone to yellowing during molding and deterioration in a moist heat environment, and a molding formed therefrom.SOLUTION: A polycarbonate resin composition has light guiding properties and contains, relative to 100 pts.wt. of (A) a polycarbonate resin composition (A component), 0.005 to 0.2 pt.wt. of (B) a thioether compound (B component) and 0.2 to 1.5 pts.wt. of a caprolactone-based polymer (C component).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polycarbonate resin composition having light-guiding properties and a molded article made thereof. More specifically, the present invention relates to a polycarbonate resin composition having excellent light-guiding properties, little yellowing during molding, and little deterioration in a humid and hot environment, and suitable for use in optical elements such as light-guiding plates, display panels, and lighting covers, and a molded article made thereof. [Background technology]

[0002] Light sources that use LEDs as a light source have been attracting attention as the next generation of light sources due to their energy-saving and long lifespan, and since the development of blue light-emitting diodes in the 1990s, the practicality of white light illumination using LEDs has increased, and commercial products have rapidly appeared, primarily for spot lighting. Furthermore, LED light sources for displays and other surface light sources have also been increasingly being converted to LEDs, as they offer the advantage of higher color purity in the light emitted by RGB three-color LEDs, compared to the colors (red, green, and blue) obtained by passing white light emitted by cold cathode fluorescent lamps through color filters, and can greatly expand the color reproduction range.

[0003] On the other hand, because LEDs are point light sources, when trying to illuminate a wide area, it is necessary to install many LEDs on the back of the light source (backlight method), and each one appears as a point light source, which means that there is a drawback in that it is prone to unevenness.Recently, in order to eliminate this unevenness and aim for cost reduction, further power saving, and even thinner products, there has been an increase in light sources using the so-called edge light method, in which LEDs are placed on the edge of the light source body.

[0004] Edge-lit light sources use light guides to transmit light over long distances to achieve uniform surface emission. However, edge-lit light sources suffer from the problem of dimming as the light source increases. Therefore, materials for light-guiding molded articles must have the property of minimizing light attenuation from the light source, i.e., light-guiding properties. Among transparent resins, polymethyl methacrylate (PMMA) has been the most suitable material to date. However, PMMA's impact resistance and thermal stability are not always sufficient, limiting its use in the aforementioned applications. Furthermore, with the shift to LED light sources, light guides are now required to have heat resistance in addition to the above properties. Therefore, technologies to improve the light-guiding properties of polycarbonate resin, which has excellent heat and impact resistance, have been attracting attention.

[0005] As an example of improving the light-guiding properties of polycarbonate, Patent Document 1 reports an aromatic polycarbonate resin composition for light guide plates, which is made by blending a specific phosphorus-based stabilizer and a mold release agent with a polycarbonate resin having a viscosity-average molecular weight of 13,000 to 15,000. However, in addition to problems with strength, there are also problems with the phosphorus-based stabilizer reducing humidity and heat resistance, limiting its applications.

[0006] Patent Documents 2 and 3 report aromatic polycarbonate resin compositions for light guide plates containing a small amount of a specific siloxane compound. However, silicone-based compounds may generate low-molecular-weight silicone gas under high-temperature conditions.

[0007] Patent Document 4 reports a light guide plate in which a light scattering layer is provided on the front or back surface of a plate-shaped molded product formed using a resin composition consisting of polycarbonate and acrylic resin. Patent Document 5 reports an aromatic polycarbonate resin composition consisting of an aromatic polycarbonate resin and another thermoplastic resin whose refractive index differs from that of the aromatic polycarbonate resin by 0.001 or more. However, acrylic resins, which are inherently incompatible with polycarbonate resins, are not suitable for use in light guide plates. However, since the resin is added, the amount of the resin to be added is limited, and the light-guiding properties may not be fully exhibited.

[0008] Patent Document 6 discloses a polycarbonate resin composition in which a caprolactone polymer is added to improve optical properties, and Patent Document 7 reports a polycarbonate resin composition in which a caprolactone polymer is added to improve moist heat resistance and long-term heat resistance. However, these compositions do not satisfy all of the light guiding properties, color hue, and moist heat resistance. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-204737 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-250557 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-157901 [Patent Document 4] Japanese Patent Application Publication No. 10-73725 [Patent Document 5] Japanese Patent Application Laid-Open No. 2002-60609 [Patent Document 6] Japanese Patent Application Laid-Open No. 2007-131679 [Patent Document 7] International Publication No. 2016 / 199783 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a polycarbonate resin composition which has excellent light-transmitting properties and is less susceptible to yellowing during molding and deterioration in a humid and hot environment, and a molded article made from the same. [Means for solving the problem]

[0011] As a result of extensive research aimed at achieving the above object, the present inventors have found that the above object can be achieved by a polycarbonate resin composition in which a thioether-based compound and a caprolactone-based polymer are blended in specific proportions with a polycarbonate resin, and have arrived at the present invention. That is, according to the present invention, the following configurations (1) to (6) are provided.

[0012] (1) A polycarbonate resin composition having light-guiding properties, characterized by containing, per 100 parts by weight of (A) polycarbonate resin (component A), 0.005 to 0.2 parts by weight of (B) a thioether-based compound (component B) and 0.2 to 1.5 parts by weight of (C) a caprolactone-based polymer (component C) having a number-average molecular weight of 300 to 8,000.

[0013] (2) The polycarbonate resin composition having light-guiding properties according to the above item (1), wherein component B is a thioether-based compound represented by the following formula [1] or the following formula [2]: (R 1 -S-CH2―CH2―C(O)O-CH2)4-C [1] [In formula [1], R 1 may be the same or different and are linear or branched alkyl groups having 4 to 20 carbon atoms.] (R 2 -OC(O)-CH2-CH2-)2-S [2] [In formula [2], R 2 may be the same or different and are linear or branched alkyl groups having 6 to 22 carbon atoms.]

[0014] (3) The polycarbonate resin composition having light-guiding properties according to the above item (1) or (2), wherein the thioether compound of component B is at least one thioether compound selected from the group consisting of dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, and pentaerythritol tetrakis(3-laurylthiopropionate).

[0015] (4) The component C is selected from a difunctional polycaprolactone diol, a trifunctional polycaprolactone triol, and a tetrafunctional polycaprolactone tetraol represented by the following formulas [3] to [5]: The polycarbonate resin composition having light-guiding properties according to any one of the above items (1) to (3), wherein the polycarbonate resin composition is at least one caprolactone polymer selected from the group consisting of:

[0016] [ka]

[0017] (wherein m+n is an integer between 3 and 35, inclusive, and R is C2H4, C2H4OC2H4, or C(CH3)2(CH2)2).

[0018] [ka]

[0019] (wherein l+m+n is an integer between 3 and 35, inclusive, and R is CH2CHCH2, CH3C(CH2)3, or CH3CH2C(CH2)3)

[0020] [ka]

[0021] (wherein k+l+m+n is an integer of 4 or greater and 35 or less, and R is C(CH2)4).

[0022] (5) The polycarbonate resin composition having light-guiding properties according to any one of (1) to (4) above, wherein the caprolactone polymer of component C has a number-average molecular weight of 500 to 5,000.

[0023] (6) A molded article made of the polycarbonate resin composition having light-guiding properties described in any one of the above items (1) to (5). [Effects of the Invention]

[0024] The polycarbonate resin composition of the present invention is a polycarbonate resin composition containing a polycarbonate resin, a thioether compound, and a caprolactone polymer, and exhibits excellent light conductivity, hue, and heat and moisture resistance. The polycarbonate resin composition of the present invention has the above mentioned effects, and thus is extremely useful for various industrial applications such as the lighting field including LED lighting, the OA equipment field, the electric and electronic equipment field, the automotive field, etc., and the industrial effects achieved thereby are extremely great. Specifically, examples include covers for lighting, diffusion plates for displays, glass substitute applications, various optical discs such as optical discs and related members, various housing molded products such as battery housings, lens barrels, memory cards, speaker cones, disk cartridges, surface light emitters, mechanical parts for micromachines, molded products with hinges or molded products for hinges, light-transmitting / light-guiding buttons, touch panel parts, etc.

Embodiments for Carrying out the Invention

[0025] Hereinafter, the details of the present invention will be described.

[0026] <Component A: Polycarbonate Resin> The polycarbonate resin used as Component A of the present invention is usually obtained by reacting a dihydroxy compound and a carbonate precursor by an interfacial polycondensation method or a melt transesterification method. In addition, it can also be obtained by polymerizing a carbonate prepolymer by a solid-phase transesterification method or by polymerizing a cyclic carbonate compound by a ring-opening polymerization method.

[0027] The dihydroxy component used here may be any of those usually used as the dihydroxy component of a polycarbonate resin, and may be bisphenols or aliphatic diols.

[0028] Examples of bisphenols include 4,4'-dihydroxybiphenyl, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 2,2-bis(4-hydroxy-3,3'-biphenyl)propane, 2,2-bis(4-hydroxy- 2,2-bis(3-isopropylphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, 2,2-bis(3-bromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl) 1,1-bis(4-hydroxyphenyl)methane, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 4,4'-sulfonyldiphenol, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 2,2'-dimethyl -4,4'-Sulfonyldiphenol, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, 2,2'-diphenyl-4,4'-sulfonyldiphenol, 4,4'-dihydroxy-3,3'-diphenyldiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-diphenyldiphenyl sulfide, 1,3-bis{2-(4-hydroxyphenyl)propyl}benzene, 1,4-bis{2-(4-hydroxyphenyl)propyl}benzene, 1,4-bis(4-hydroxyphenyl)cyclohexane, 1,3-bis(4-hydroxyphenyl)cyclohexane, 4,8-bis(4-hydroxyphenyl)tricyclo[5.2.1.02,6]decane, 4,4'-(1,3-adamantanediyl)diphenol, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, and bisphenol A having a siloxane structure represented by the following general formula [6]: phenol compounds and the like.

[0029] [ka]

[0030] [In the formula, R 3 and R 4 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms; R 5 , R 6 , R 7 , R 8 , R 9 and R 10 are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, p and q are each an integer of 1 to 4, e is a natural number, f is 0 or a natural number, and e+f is a natural number less than 100. X is a divalent aliphatic group having 2 to 8 carbon atoms.]

[0031] Examples of aliphatic diols include 2,2-bis-(4-hydroxycyclohexyl)-propane, 1,14-tetradecanediol, octaethylene glycol, 1,16-hexadecanediol, 4,4'-bis(2-hydroxyethoxy)biphenyl, bis{(2-hydroxyethoxy)phenyl}methane, 1,1-bis{(2-hydroxyethoxy)phenyl}ethane, 1,1-bis{(2-hydroxyethoxy)phenyl}-1-phenylethane, 2,2-bis{(2-hydroxyethoxy)phenyl}propane, 2,2-bis{(2-hydroxy 2,2-bis{4-(2-hydroxyethoxy)-3-methylphenyl}propane, 1,1-bis(2-hydroxyethoxy)phenyl}-3,3,5-trimethylcyclohexane, 2,2-bis{4-(2-hydroxyethoxy)-3,3'-biphenyl}propane, 2,2-bis{(2-hydroxyethoxy)-3-isopropylphenyl}propane, 2,2-bis{3-t-butyl-4-(2-hydroxyethoxy)phenyl}propane, 2,2-bis{(2-hydroxyethoxy)phenyl}butane, 2,2-bis{(2-hydroxyethoxy)phenyl}-4-methylpentane, 2 ,2-bis{(2-hydroxyethoxy)phenyl}octane, 1,1-bis{(2-hydroxyethoxy)phenyl}decane, 2,2-bis{3-bromo-4-(2-hydroxyethoxy)phenyl}propane, 2,2-bis{3,5-dimethyl-4-(2-hydroxyethoxy)phenyl}propane, 2,2-bis{3-cyclohexyl-4-(2-hydroxyethoxy)phenyl}propane, 1,1-bis{3-cyclohexyl-4-(2-hydroxyethoxy)phenyl}cyclohexane, bis{(2-hydroxyethoxy)phenyl}diphenyl Methane, 9,9-bis{(2-hydroxyethoxy)phenyl}fluorene, 9,9-bis{4-(2-hydroxyethoxy)-3-methylphenyl}fluorene, 1,1-bis{(2-hydroxyethoxy)phenyl}cyclohexane, 1,1-bis{(2-hydroxyethoxy)phenyl}cyclopentane, 4,4'-bis(2-hydroxyethoxy)diphenyl ether, 4,4'-bis(2-hydroxyethoxy)-3,3'-dimethyldiphenyl ether, 1,3-bis[2-{(2-hydroxyethoxy)phenyl}propyl]benzene, 1,Examples include 4-bis[2-{(2-hydroxyethoxy)phenyl}propyl]benzene, 1,4-bis{(2-hydroxyethoxy)phenyl}cyclohexane, 1,3-bis{(2-hydroxyethoxy)phenyl}cyclohexane, 4,8-bis{(2-hydroxyethoxy)phenyl}tricyclo[5.2.1.02,6]decane, 1,3-bis{(2-hydroxyethoxy)phenyl}-5,7-dimethyladamantane, 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro(5,5)undecane, 1,4:3,6-dianhydro-D-sorbitol (isosorbide), 1,4:3,6-dianhydro-D-mannitol (isomannide), and 1,4:3,6-dianhydro-L-iditol (isoidide).

[0032] Among these, aromatic bisphenols are preferred, and in particular, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4'-sulfonyldiphenol, 2,2'-dimethyl-4,4'-sulfonyldiphenol, 9,9 ... Preferred are 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-sulfonyldiphenol, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,3-bis{2-(4-hydroxyphenyl)propyl}benzene, and 1,4-bis{2-(4-hydroxyphenyl)propyl}benzene, and bisphenol compounds represented by the above general formula [6]. 2,2-bis(4-hydroxyphenyl)propane, which has excellent strength and durability, is the most suitable. These may be used alone or in combination.

[0033] The polycarbonate resin used as component A of the present invention may be made into a branched polycarbonate resin by using a branching agent in combination with the above-mentioned dihydroxy compound. Examples of polyfunctional aromatic compounds having three or more functional groups that can be used in such branched polycarbonate resins include phloroglucin, phloroglucside, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2,2,4,6-trimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1-tris(4-hydroxyphenyl)ethane, 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane, 26-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, 4-[4-[1,1-bis(4- Examples of the 4-hydroxyphenyl ether include trisphenols such as {4-hydroxyphenyl)ethyl]benzene}-α,α-dimethylbenzylphenol, tetra(4-hydroxyphenyl)methane, bis(2,4-dihydroxyphenyl)ketone, 1,4-bis(4,4-dihydroxytriphenylmethyl)benzene, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, and acid chlorides thereof. Among these, 1,1,1-tris(4-hydroxyphenyl)ethane and 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane are preferred, and 1,1,1-tris(4-hydroxyphenyl)ethane is particularly preferred.

[0034] These polycarbonate resins are produced by known reaction means for producing ordinary aromatic polycarbonate resins, for example, by reacting an aromatic dihydroxy component with a carbonate precursor such as phosgene or a carbonate diester. The basic means for this production method will be briefly explained.

[0035] Reactions using, for example, phosgene as a carbonate precursor are typically carried out in the presence of an acid binder and a solvent. Examples of acid binders include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, or amine compounds such as pyridine. Examples of solvents include halogenated hydrocarbons such as methylene chloride and chlorobenzene. To accelerate the reaction, a catalyst such as a tertiary amine or a quaternary ammonium salt can also be used. The reaction temperature is typically 0 to 40°C, and the reaction time is several minutes to 5 hours. Transesterification reactions using a carbonate diester as a carbonate precursor are carried out by stirring a predetermined ratio of aromatic dihydroxy components with the carbonate diester under heating in an inert gas atmosphere, and then distilling off the resulting alcohol or phenol. The reaction temperature varies depending on the boiling point of the resulting alcohol or phenol, but is typically in the range of 120 to 300°C. The reaction is completed by reducing the pressure from the beginning of the reaction to distill off the resulting alcohol or phenol. To accelerate the reaction, a catalyst typically used in transesterification reactions can also be used. Examples of the carbonic acid diester used in the transesterification reaction include diphenyl carbonate, dinaphthyl carbonate, bis(diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, etc. Among these, diphenyl carbonate is particularly preferred.

[0036] In the present invention, a terminal terminator is used in the polymerization reaction. The terminal terminator is used to adjust the molecular weight, and the resulting polycarbonate resin has excellent thermal stability compared to unterminated polycarbonate resins because the terminals are blocked. Examples of such terminal terminators include monofunctional phenols represented by the following general formulas [7] to [9].

[0037] [ka]

[0038] [In formula [7], A is a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, an alkylphenyl group (the alkyl portion has 1 to 9 carbon atoms), a phenyl group, or a phenylalkyl group (the alkyl portion has 1 to 9 carbon atoms), and r is an integer of 1 to 5, preferably 1 to 3.]

[0039] [ka]

[0040] [ka]

[0041] [In the formulas [8] and [9], Y is -RO-, -R-CO-O-, or -RO-CO-, where R represents a single bond or a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and n represents an integer of 10 to 50.]

[0042] Specific examples of the monofunctional phenols represented by the general formula [7] include phenol, isopropylphenol, p-tert-butylphenol, p-cresol, p-cumylphenol, 2-phenylphenol, 4-phenylphenol, and isooctylphenol.

[0043] Furthermore, the monofunctional phenols represented by the above general formula [8] or [9] are phenols having a long-chain alkyl group or an aliphatic ester group as a substituent. When these are used to block the ends of polycarbonate resin, they not only function as an end terminator or molecular weight modifier, but also improve the melt fluidity of the resin, facilitating molding and processing, and have the effect of lowering the water absorption of the resin, and are therefore preferably used.

[0044] As the substituted phenols of the above general formula [8], those in which n is 10 to 30, particularly 10 to 26, are preferred. Specific examples thereof include decylphenol, dodecylphenol, tetraphenylphenol, Examples include decylphenol, hexadecylphenol, octadecylphenol, eicosylphenol, docosylphenol, and triacontylphenol.

[0045] Furthermore, as the substituted phenols of the above general formula [9], compounds in which Y is -R-COO- and R is a single bond are suitable, and those in which n is 10 to 30, particularly 10 to 26, are preferred, and specific examples thereof include decyl hydroxybenzoate, dodecyl hydroxybenzoate, tetradecyl hydroxybenzoate, hexadecyl hydroxybenzoate, eicosyl hydroxybenzoate, docosyl hydroxybenzoate, and triacontyl hydroxybenzoate.

[0046] Among these monofunctional phenols, the monofunctional phenols represented by the above general formula [7] are preferred, more preferably alkyl-substituted or phenylalkyl-substituted phenols, and particularly preferably p-tert-butylphenol, p-cumylphenol or 2-phenylphenol.

[0047] It is desirable that these monofunctional phenolic end-capping agents be introduced into the terminals in an amount of at least 5 mol %, preferably at least 10 mol %, based on the total terminals of the obtained polycarbonate resin. The end-capping agents may be used alone or in combination of two or more.

[0048] The polycarbonate resin used as component A of the present invention may be a polyester carbonate copolymerized with an aromatic dicarboxylic acid, such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or a derivative thereof, within the scope of the present invention.

[0049] The viscosity average molecular weight of the polycarbonate resin used as Component A of the present invention is preferably in the range of 11,500 to 50,000, more preferably 12,500 to 40,000, still more preferably in the range of 13,500 to 35,000, and most preferably in the range of 15,000 to 30,000. When the molecular weight exceeds 50,000, the melt viscosity may become too high and the moldability may be poor. When the molecular weight is less than 11,500, problems may occur in mechanical strength. The viscosity average molecular weight referred to in the present invention is obtained by first determining the specific viscosity calculated by the following formula from a solution prepared by dissolving 0.7 g of the polycarbonate resin in 100 ml of methylene chloride at 20°C using an Ostwald viscometer, and then inserting the obtained specific viscosity into the following formula to obtain the viscosity average molecular weight Mv. Specific viscosity (η SP ) = (t - t0) / t0 [t0 is the dropping seconds of methylene chloride, t is the dropping seconds of the sample solution] η SP / c = [η] + 0.45×[η] 2 c (where [η] is the intrinsic viscosity) [η] = 1.23×10 -4 Mv 0.83 c = 0.7

[0050] The total amount of Cl (chlorine) in the polycarbonate resin used as Component A of the present invention is preferably 0 to 50 ppm, more preferably from 0 to 350 ppm. When the total amount of Cl in the polycarbonate resin is within the above range, it is excellent in hue and thermal stability and is preferable.

[0051] <Component B: Thioether compound> The thioether compound used as Component B of the present invention improves the light guiding performance of the polycarbonate resin, improves the thermal stability during production or molding, and improves the mechanical properties, hue, and molding stability. The thioether compound used in the present invention is preferably at least one thioether compound selected from the group consisting of the compounds represented by the following formula [1] and the following formula [2]. (R 1 -S-CH2―CH2―C(O)O-CH2)4-C 〔1〕 [In the formula, R 1 may be the same or different and are linear or branched alkyl groups having 4 to 20 carbon atoms.] (R 2 -OC(O)-CH2-CH2-)2-S [2] [In the formula, R 2 may be the same or different and are linear or branched alkyl groups having 6 to 22 carbon atoms.]

[0052] In the thioether compound represented by the formula [1], R 1 is an alkyl group having 4 to 20 carbon atoms, preferably an alkyl group having 10 to 18 carbon atoms. Specific examples include pentaerythritol tetrakis(3-laurylthiopropionate), pentaerythritol tetrakis(3-myristylthiopropionate), pentaerythritol tetrakis(3-stearylthiopropionate), etc., and among these, pentaerythritol tetrakis(3-laurylthiopropionate) and pentaerythritol tetrakis(3-myristylthiopropionate) are preferred, with pentaerythritol tetrakis(3-laurylthiopropionate) being particularly preferred.

[0053] In addition, in the thioether compound represented by the formula [2], R 2 is an alkyl group having 6 to 22 carbon atoms, preferably an alkyl group having 10 to 18 carbon atoms. Specific examples include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, etc., and among these, dilauryl-3,3'-thiodipropionate and dimyristyl-3,3'-thiodipropionate are preferred, with dimyristyl-3,3'-thiodipropionate being particularly preferred.

[0054] The content of the thioether-based compound is in the range of 0.005 to 0.2 parts by weight with respect to 100 parts by weight of the polycarbonate resin, preferably in the range of 0.01 to 0.15 parts by weight, and most preferably in the range of 0.02 to 0.1 parts by weight. If it is less than 0.005 parts by weight, excellent light conductivity cannot be obtained, and the discoloration suppression effect during molding is insufficient, which is not preferable. Also, even if an amount exceeding 0.2 parts by weight is blended, no higher improvement in effect is observed, and rather the heat resistance decreases, which is not preferable.

[0055] Thioether-based compounds are commercially available from Sumitomo Chemical Co., Ltd. as Sumilizer TP-D (trade name) and from BASF as Irganox PS802FL (trade name), etc., and can be easily used.

[0056] <Component C: Caprolactone-based polymer> The caprolactone-based polymer used as Component C of the present invention improves the light guiding performance of the polycarbonate resin, improves the thermal stability during production or molding processing, and improves the mechanical properties, hue, and molding stability.

[0057] The caprolactone-based polymer used as Component C is a polymer of caprolactone, particularly ε-caprolactone, that is, the repeating unit is (-CH2-CH2-CH2-CH2-CH2-C(O)-O-), and part of the hydrogen atoms of the methylene chain of the caprolactone polymer or the repeating unit may be substituted with a halogen atom or a hydrocarbon group. Also, the terminals of the polycaprolactone may be subjected to terminal treatment such as esterification or etherification.

[0058] The structure of the polycaprolactone may have a bifunctional, trifunctional or tetrafunctional structure such as polycaprolactone diol like a polymer of ε-caprolactone, polycaprolactone triol or polycaprolactone tetraol.

[0059] Specifically, the caprolactone polymer used in the present invention is preferably at least one caprolactone polymer selected from the group consisting of bifunctional polycaprolactone diols, trifunctional polycaprolactone triols, and tetrafunctional caprolactone tetraols represented by the following formulas [3] to [5].

[0060] [ka]

[0061] (wherein m+n is an integer between 3 and 35, inclusive, and R is C2H4, C2H4OC2H4, or C(CH3)2(CH2)2).

[0062] [ka]

[0063] (wherein l+m+n is an integer between 3 and 35, inclusive, and R is CH2CHCH2, CH3C(CH2)3, or CH3CH2C(CH2)3)

[0064] [ka]

[0065] (wherein k+l+m+n is an integer of 4 or greater and 35 or less, and R is C(CH2)4).

[0066] The molecular weight of the caprolactone polymer used in the present invention is, in terms of polystyrene equivalent number average molecular weight by GPC, in the range of 300 to 8,000, preferably 400 to 6,000, more preferably 500 to 5,000, still more preferably 700 to 4,000, particularly preferably 800 to 3,000, and most preferably 1,000 to 2,000. If the number average molecular weight of the caprolactone polymer exceeds 8,000, it will be poorly dispersible in polycarbonate resin, and its effect of enhancing light guiding properties will be diminished, while if it is less than 300, it will have an adverse effect on the heat resistance of the polycarbonate resin.

[0067] The content of the caprolactone polymer is in the range of 0.2 to 1.5 parts by weight, preferably 0.3 to 1.3 parts by weight, more preferably 0.4 to 1.2 parts by weight, and even more preferably 0.5 to 1.0 parts by weight, relative to 100 parts by weight of the polycarbonate resin. If the content is less than 0.2 parts by weight, excellent light-guiding properties cannot be obtained, and if the content is more than 1.5 parts by weight, heat resistance and mechanical strength will be adversely affected.

[0068] <Other ingredients> Other resins and fillers may be blended into the polycarbonate resin composition of the present invention as long as they do not impair transparency, light-guiding properties, etc. However, since many other resins and fillers impair transparency, the type and amount of such resins and fillers should be selected taking this into consideration.

[0069] Taking the above points into consideration, additives used to improve thermal stability, designability, etc. can be advantageously used in the polycarbonate resin composition of the present invention. These additives will be specifically described below.

[0070] (I) Heat stabilizer The polycarbonate resin composition of the present invention may contain various known heat stabilizers, such as phosphorus-based antioxidants and phenol-based antioxidants.

[0071] Specific examples of such phosphorus-based antioxidants include phosphorous acid (phosphite), phosphonite, phosphinite, phosphine, phosphoric acid (phosphate), phosphonate, phosphinate, and phosphine oxide, and among these, phosphites, phosphonites, phosphines, phosphonates, and phosphates are preferably used. Specific examples of the phosphite compound include trimethyl phosphite, triethyl phosphite, tripropyl phosphite, triisopropyl phosphite, tributyl phosphite, 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, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, tris(diethylphenyl)phosphite, tris(di-isopropylphenyl)phosphite, phenyl)phosphite, tris(di-n-butylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tris(2,6-di-tert-butylphenyl)phosphite, distearyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-ethylphenyl)pentaerythritol diphosphite, phenyl bisphenol A pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, dicyclohexyl pentaerythritol diphosphite, etc. Furthermore, as other phosphite compounds, those which react with dihydric phenols to form a cyclic structure can also be used.For example, 2,2'-methylenebis(4,6-di-tert-butylphenyl)(2,4-di-tert-butylphenyl)phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite, 2,2'-methylenebis(4-methyl-6-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite, 2,2'-ethylidenebis(4-methyl-6-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite, and the like can be mentioned.

[0072] Examples of phosphonite compounds include tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, and tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite. (2,6-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite, bis(2,4-di-tert-butylphenyl)-4-phenyl-phenylphosphonite, bis(2,4-di-tert-butylphenyl)-3-phenyl-phenylphosphonite, bis(2,6-di-n-butylphenyl)-3-phenyl-phenylphosphonite, bis(2,6-di-tert-butylphenyl) Examples of suitable phosphonite compounds include tetrakis(di-tert-butylphenyl)-biphenylene diphosphonite and bis(di-tert-butylphenyl)-phenyl-phenylphosphonite, with tetrakis(di-tert-butylphenyl)-biphenylene diphosphonite and bis(di-tert-butylphenyl)-phenyl-phenylphosphonite being preferred, and tetrakis(2,4-di-tert-butylphenyl)-biphenylene diphosphonite and bis(2,4-di-tert-butylphenyl)-phenyl-phenylphosphonite being more preferred. Such phosphonite compounds can be used in combination with, and are preferred for, the above-mentioned phosphite compounds having an aryl group substituted with two or more alkyl groups.

[0073] Examples of the phosphine compound include triethylphosphine, tripropylphosphine, tributylphosphine, trioctylphosphine, triamylphosphine, dimethylphenylphosphine, dibutylphenylphosphine, diphenylmethylphosphine, diphenyloctylphosphine, triphenylphosphine, tri-p-tolylphosphine, trinaphthylphosphine, and diphenylbenzylphosphine. A particularly preferred phosphine compound is triphenylphosphine.

[0074] Examples of the phosphonate compound include dimethyl benzenephosphonate, diethyl benzenephosphonate, and dipropyl benzenephosphonate.

[0075] Examples of the phosphate compound include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorthoxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, and diisopropyl phosphate, and preferred are triphenyl phosphate and trimethyl phosphate.

[0076] Specific examples of the phenolic antioxidant include vitamin E, n-octadecyl-β-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, 2-tert-butyl-6-(3'-tert-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenylacrylate, 2,6-di-tert-butyl-4-(N,N-dimethylaminomethyl)phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, 2,2'-methylenebis(4-methyl-6-tert-butylphenyl)propionate, phenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-dimethylene-bis(6-α-methyl-benzyl-p-cresol) 2,2'-ethylidene-bis(4,6-di-tert-butylphenol), 2,2'-butylidene-bis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol) , triethylene glycol-N-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis[2-tert-butyl-4-methyl 6-(3-tert-butyl-5-methyl-2-hydroxybenzyl)phenyl]terephthalate, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1,-dimethylethyl}-2,4,8,10 -Tetraoxaspiro[5,5]undecane, 4,4'-thiobis(6-tert-butyl-m-cresol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 4,4'-di-thiobis(2,6-di-tert-butylphenol), 4,4'-tri-thiobis(2,6-di-tert-butylphenol), 2,4-bis(n-octylthio)-6-(4-hydroxy-3',5'-di-tert-butylanilino)-1,3,5-triazine, N,N'-hexamethylenebis-(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-tert-butyl-4- Examples of suitable isocyanurates include tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 1,3,5-tris-2[3(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanurate, and tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate]methane.

[0077] Among these, n-octadecyl-β-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, 2-tert-butyl-6-(3'-tert-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, and tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate]methane are preferred, and n-octadecyl-β-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate is more preferred.

[0078] The phosphorus-based antioxidants and phenol-based antioxidants listed above can be used alone or in combination of two or more. The content of these phosphorus-based antioxidants or phenol-based antioxidants is preferably 0.0001 to 1 part by weight per 100 parts by weight of component A, more preferably 0.0005 to 0.5 parts by weight, and even more preferably 0.001 to 0.2 parts by weight.

[0079] Since a large amount of phosphorus-based antioxidant, particularly phosphite-based antioxidant, is added, the moist heat resistance of the polycarbonate resin decreases, so the amount is preferably less than 0.02 part by weight, more preferably 0.015 part by weight or less, even more preferably 0.01 part by weight or less, particularly preferably 0.005 part by weight or less, and most preferably 0.001 part by weight or less. It is also preferable that substantially no antioxidant is added.

[0080] (II) Mold release agent A mold release agent can be blended into the polycarbonate resin composition of the present invention as needed. Such mold release agents can be those known per se. Examples include saturated fatty acid esters, unsaturated fatty acid esters, polyolefin waxes (including polyethylene waxes or 1-alkene polymers. These may also be modified with functional group-containing compounds, such as acid-modified waxes), silicone compounds, fluorine compounds, paraffin wax, and beeswax. Among these, saturated fatty acid esters, linear or cyclic polydimethylsiloxane oils, polymethylphenylsilicone oils, and fluorine oils are particularly preferred. are preferred. Particularly preferred release agents include saturated fatty acid esters, for example, monoglycerides such as stearic acid monoglyceride, polyglycerol fatty acid esters such as decaglycerol deca-stearate and decaglycerol tetrastearate, lower fatty acid esters such as stearic acid stearate, higher fatty acid esters such as sebacate behenate, and erythritol esters such as pentaerythritol tetrastearate. The content of such a release agent is preferably 0.01 to 1 part by weight per 100 parts by weight of component A.

[0081] (III) UV absorbers The polycarbonate resin composition of the present invention can contain an ultraviolet absorber, if necessary. Examples of such ultraviolet absorbers include benzophenone-based ultraviolet absorbers such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sodium sulfoxybenzophenone, and bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane.

[0082] Examples of ultraviolet absorbers include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-3'-dodecyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-bis(α,α'-dimethylbenzyl)phenylbenzotriazole, 2-[2'-hydroxy-3'- Examples of benzotriazole-based ultraviolet absorbers include (3”,4”,5”,6”-tetraphthalimidomethyl)-5’-methylphenyl]benzotriazole, 2-(2’-hydroxy-3’-tert-butyl-5’-methylphenyl)-5-chlorobenzotriazole, 2-(2’-hydroxy-3’,5’-di-tert-butylphenyl)-5-chlorobenzotriazole, 2,2’methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], and methyl-3-[3-tert-butyl-5-(2H-benzotriazol-2-yl)-4-hydroxyphenylpropionate-polyethylene glycol condensate.

[0083] Further examples of the ultraviolet absorber include hydroxyphenyltriazine compounds typified by 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxy-phenol and 2-(4,6-bis-(2,4-dimethylphenyl-1,3,5-triazin-2-yl)-5-hexyloxy-phenol, and malonic acid ester compounds typified by 2-(1-arylalkylidene)malonic acid esters such as Hostavin PR-25 manufactured by Clariant Japan and Hostavin B-CAP manufactured by Clariant Japan.

[0084] The content of the ultraviolet absorber is preferably 0.01 to 5 parts by weight, and more preferably 0.02 to 1 part by weight, per 100 parts by weight of the component A.

[0085] (IV) Light stabilizers The polycarbonate resin composition of the present invention may contain a light stabilizer as needed. Examples of such light stabilizers include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2n-butylmalonate, a condensation product of 1,2,3,4-butanecarboxylic acid, 2,2,6,6-tetramethyl-4-piperidinol, and tridecyl alcohol, and a condensation product of 1,2,3,4-butanedicarboxylic acid and 1,2,2,6,6- Condensation product of pentamethyl-4-piperidinol and tridecyl alcohol, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, poly{[6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethylpiperidyl)imino]hexamethylene[(2,2,6,6-tetramethylpiperidyl)imino]hexamethylene Poly{[6-morpholino-s-triazine-2,4-diyl][(2,2,6,6-tetramethylpiperidyl)imino]hexamethylene[(2,2,6,6-tetramethylpiperidyl)imino]}, condensation product of 1,2,3,4-butanetetracarboxylic acid, 2,2,6,6-tetramethyl-4-piperidinol and β,β,β',β'-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5,5]undecane)diethanol, N,N'-bis(3-aminopropyl)ethylenediamine and 2,4- Examples of hindered amines include a condensation product of bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino]-chloro-1,3,5-triazine, a condensation product of 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol, and β,β,β',β'-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5,5]undecane)diethanol, and polymethylpropyl 3-oxy-[4-(2,2,6,6-tetramethyl)piperidinyl]siloxane.The content of the light stabilizer is preferably 0.01 to 5 parts by weight, and more preferably 0.02 to 1 part by weight, per 100 parts by weight of the component A.

[0086] (V) Bluing agent The polycarbonate resin composition of the present invention can be blended with a bluing agent to counteract the yellowish color due to the ultraviolet absorber or the like. Any bluing agent typically used in polycarbonate resins can be used without any particular problems. In general, anthraquinone dyes are easily available and are therefore preferred. Specific examples of bluing agents include Solvent Violet 13 (CA. No. (Color Index No.) 60725; trademarks of Bayer's Macrolex Violet B, Mitsubishi Chemical's Diaresin Blue G, and Sumitomo Chemical's Sumiplast Violet B), Solvent Violet 31 (CA. No. 68210; trademark of Mitsubishi Chemical's Diaresin Violet D), Solvent Violet 33 (CA. No. 60725; trademark of Mitsubishi Chemical's Diaresin Blue J), ​​Solvent Blue 94 (CA. No. 61500; trademark of Mitsubishi Chemical's Diaresin Blue N), Solvent Violet 36 (CA. No. 68210; trademark of Bayer's Macrolex Violet 3R), and Solvent Blue 97 (trademark of Examples include Macrolex Blue RR (manufactured by Bayer) and Solvent Blue 45 (CA. No. 61110; trade name: Terazol Blue RLS (manufactured by Sandoz)), with Macrolex Blue RR, Macrolex Violet B, and Terazol Blue RLS being particularly preferred. The content of the bluing agent is preferably 0.000005 to 0.001 part by weight, and more preferably 0.00001 to 0.0001 part by weight, per 100 parts by weight of component A.

[0087] (VI) Fluorescent whitening agents In the polycarbonate resin composition of the present invention, the fluorescent brightener is not particularly limited as long as it is used to improve the color tone of the resin or the like to white or bluish white. Examples include stilbene-based, benzimidazole-based, benzoxazole-based, naphthalimide-based, rhodamine-based, coumarin-based, and oxazine-based compounds. Specific examples include CI Fluorescent Brightener 219:1, Eastman Chemical Company's EASTOBRITE OB-1, and Hakkol Chemical Company's "Hakkol PSR." Here, the fluorescent brightener has the effect of absorbing ultraviolet energy in light and radiating this energy in the visible region. The content of the fluorescent brightener is preferably 0.001 to 0.1 parts by weight, more preferably 0.001 to 0.05 parts by weight, per 100 parts by weight of Component A.

[0088] (VII) Epoxy compounds An epoxy compound can be blended into the polycarbonate resin composition of the present invention as needed. Such epoxy compounds are blended for the purpose of inhibiting mold corrosion, and essentially any epoxy functional group can be used. Specific examples of preferred epoxy compounds include 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, copolymers of methyl methacrylate and glycidyl methacrylate, and copolymers of styrene and glycidyl methacrylate. The amount of such epoxy compound added is preferably 0.003 to 0.2 parts by weight, more preferably 0.004 to 0.15 parts by weight, and even more preferably 0.005 to 0.1 parts by weight, per 100 parts by weight of Component A.

[0089] (VIII) Organic metal salts An organic metal salt compound can be blended into the polycarbonate resin composition of the present invention. Such organic metal salts are blended for the purpose of imparting flame retardancy. They are preferably alkali (earth) metal salts of organic acids having 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, and more preferably alkali (earth) metal salts of organic sulfonic acids. Examples of alkali (earth) metal salts of organic sulfonic acids include metal salts of fluorine-substituted alkylsulfonic acids, such as metal salts of perfluoroalkylsulfonic acids having 1 to 10 carbon atoms, preferably 2 to 8 carbon atoms, with alkali metals or alkaline earth metals, and metal salts of aromatic sulfonic acids having 7 to 50 carbon atoms, preferably 7 to 40 carbon atoms, with alkali metals or alkaline earth metals. Examples of alkali metals constituting the metal salts include lithium, sodium, potassium, rubidium, and cesium, and examples of alkaline earth metals include beryllium, magnesium, calcium, strontium, and barium. Alkali metals are more preferred. Among these alkali metals, rubidium and cesium, which have larger ionic radii, are preferred when higher transparency is required. However, these metals are not widely used and are difficult to purify, which can result in cost disadvantages. On the other hand, metals with smaller ionic radii, such as lithium and sodium, can be disadvantageous in terms of flame retardancy. Taking these factors into consideration, different alkali metals can be used in alkali metal sulfonates. However, potassium sulfonate, which has an excellent balance of properties in all respects, is most preferred. Such potassium salts can also be used in combination with alkali metal sulfonates made from other alkali metals.

[0090] Specific examples of alkali metal salts of perfluoroalkylsulfonic acid include potassium trifluoromethanesulfonate, potassium perfluorobutanesulfonate, potassium perfluorohexanesulfonate, potassium perfluorooctane sulfonate, sodium pentafluoroethanesulfonate, sodium perfluorobutanesulfonate, sodium perfluorooctane sulfonate, lithium trifluoromethanesulfonate, lithium perfluorobutanesulfonate, lithium perfluoroheptanesulfonate, cesium trifluoromethanesulfonate, cesium perfluorobutanesulfonate, and perfluorooctane sulfonate. Examples of suitable perfluoroalkyl sulfonates include cesium perfluorohexanesulfonate, cesium perfluorohexanesulfonate, rubidium perfluorobutanesulfonate, and rubidium perfluorohexanesulfonate. These can be used alone or in combination of two or more. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 18, more preferably 1 to 10, and even more preferably 1 to 8. Among these, potassium perfluorobutanesulfonate is particularly preferred. Perfluoroalkyl sulfonate alkali (earth) metal salts of alkali metals usually contain a significant amount of fluoride ions. The presence of such fluoride ions can reduce flame retardancy, so it is preferable to reduce their content as much as possible. The proportion of such fluoride ions can be measured by ion chromatography. The fluoride ion content is preferably 100 ppm or less, more preferably 40 ppm or less, and particularly preferably 10 ppm or less. For production efficiency, a fluoride ion content of 0.2 ppm or more is preferred. Such alkali (earth) metal perfluoroalkylsulfonate salts with reduced fluoride ion content can be produced by known methods, including reducing the amount of fluoride ions contained in the raw materials used to produce the fluorine-containing organometallic salt, removing hydrogen fluoride and other products obtained by the reaction by heating or using gases generated during the reaction, and reducing the amount of fluoride ions by purifying the fluorine-containing organometallic salt using recrystallization, reprecipitation, or other purification methods. Because organometallic flame retardants are relatively soluble in water, they are preferably produced using ion-exchanged water, particularly water with an electrical resistance of 18 MΩ cm or more, i.e., an electrical conductivity of approximately 0.55 μS / cm or less, by dissolving and washing the product at a temperature higher than room temperature, followed by cooling and recrystallization.Specific examples of the alkali (earth) metal salts of aromatic sulfonates include disodium diphenyl sulfide-4,4'-disulfonate, dipotassium diphenyl sulfide-4,4'-disulfonate, potassium 5-sulfoisophthalate, sodium 5-sulfoisophthalate, polysodium polyethylene terephthalate polysulfonate, calcium 1-methoxynaphthalene-4-sulfonate, disodium 4-dodecylphenyl ether disulfonate, polysodium poly(2,6-dimethylphenylene oxide) polysulfonate, polysodium poly(1,3-phenylene oxide) polysulfonate, polysodium poly(1,4-phenylene oxide) polysulfonate, polypotassium poly(2,6-diphenylphenylene oxide) polysulfonate, lithium poly(2-fluoro-6-butylphenylene oxide) polysulfonate, potassium sulfonate of benzenesulfonate, sodium benzenesulfonate, and benzenesulfonic acid Examples of suitable sulfonates include strontium, magnesium benzenesulfonate, dipotassium p-benzenedisulfonate, dipotassium naphthalene-2,6-disulfonate, calcium biphenyl-3,3'-disulfonate, sodium diphenylsulfone-3-sulfonate, potassium diphenylsulfone-3-sulfonate, dipotassium diphenylsulfone-3,3'-disulfonate, dipotassium diphenylsulfone-3,4'-disulfonate, sodium α,α,α-trifluoroacetophenone-4-sulfonate, dipotassium benzophenone-3,3'-disulfonate, disodium thiophene-2,5-disulfonate, dipotassium thiophene-2,5-disulfonate, calcium thiophene-2,5-disulfonate, sodium benzothiophenesulfonate, potassium diphenylsulfoxide-4-sulfonate, a formalin condensate of sodium naphthalenesulfonate, and a formalin condensate of sodium anthracenesulfonate. Of these alkali (earth) metal salts of aromatic sulfonic acid, potassium salts are particularly preferred.Among these alkali (earth) metal salts of aromatic sulfonates, potassium diphenylsulfone-3-sulfonate and dipotassium diphenylsulfone-3,3'-disulfonate are preferred, and mixtures thereof (with a weight ratio of the former to the latter of 15 / 85 to 30 / 70) are particularly preferred.

[0091] Suitable examples of organic metal salts other than alkali (earth) metal sulfonates include alkali (earth) metal salts of sulfates and alkali (earth) metal salts of aromatic sulfonamides. Examples of alkali (earth) metal salts of sulfates include alkali (earth) metal salts of sulfates of monohydric and / or polyhydric alcohols. Examples of sulfates of hydric and / or polyhydric alcohols include methyl sulfate, ethyl sulfate, lauryl sulfate, hexadecyl sulfate, sulfates of polyoxyethylene alkylphenyl ethers, mono-, di-, tri-, and tetrasulfates of pentaerythritol, sulfates of lauric acid monoglyceride, sulfates of palmitic acid monoglyceride, and sulfates of stearic acid monoglyceride. Alkali (earth) metal salts of these sulfates include, preferably, alkali (earth) metal salts of lauryl sulfate. Examples of alkali (earth) metal salts of aromatic sulfonamides include, for example, saccharin, N-(p-tolylsulfonyl)-p-toluenesulfonimide, N-(N'-benzylaminocarbonyl)sulfanilimide, and alkali (earth) metal salts of N-(phenylcarboxyl)sulfanilimide. The content of the organometallic salt is preferably 0.001 to 1 part by weight, more preferably 0.005 to 0.5 part by weight, still more preferably 0.01 to 0.3 part by weight, and particularly preferably 0.03 to 0.15 part by weight, per 100 parts by weight of component A.

[0092] (IX) Other In addition to the above, known additives can be blended into the resin composition of the present invention to impart various functions to the molded article or improve its properties, as long as the objectives of the present invention are not impaired. Such additives include reinforcing fillers, sliding agents (e.g., PTFE particles), colorants, fluorescent dyes, inorganic phosphors (e.g., phosphors with aluminate as the host crystal), antistatic agents, crystal nucleating agents, inorganic and organic antibacterial agents, photocatalytic antifouling agents (e.g., fine particle titanium oxide, fine particle zinc oxide), light diffusing agents, flow modifiers, radical generators, infrared absorbers (heat ray absorbers), and photochromic agents.

[0093] <Production of Polycarbonate Resin Composition> Any method can be used to produce the polycarbonate resin composition of the present invention. For example, components A, B, C, and optionally other components may be thoroughly mixed using a premixing device such as a V-type blender, Henschel mixer, mechanochemical device, or extrusion mixer, followed by granulation using an extrusion granulator or briquetting machine, if necessary, followed by melt-kneading using a melt mixer such as a vented twin-screw extruder, and pelletization using a pelletizer or other device. Other methods include feeding components A, B, C, and optionally other components independently to a melt mixer such as a vented twin-screw extruder, premixing component A and a portion of the other components and then feeding the remaining components to the melt mixer separately, diluting and mixing component B with water or an organic solvent and then feeding the mixture to the melt mixer, or premixing the diluted mixture with the other components and then feeding the mixture to the melt mixer. When the components to be blended are liquid, a so-called liquid injection device or liquid addition device can be used to supply the components to the melt kneader.

[0094] <Manufacturing of molded products> Any method can be used to produce a molded article made from the polycarbonate resin composition of the present invention. For example, the polycarbonate resin composition can be kneaded using an extruder, Banbury mixer, or roll, and then molded by a conventional method such as injection molding, extrusion molding, or compression molding to obtain a molded article. Furthermore, a surface light source can be produced by forming a molded plate into a plate shape, providing a light source on at least one side of the molded plate and attaching a reflector to one side of the molded plate. As light sources for such molded plates and surface light sources, fluorescent lamps as well as self-luminous materials such as cold cathode tubes, LEDs, laser diodes, and organic electroluminescence (EL) can be used. The molded articles, such as molded plates and surface light sources obtained by the present invention, can be used for mobile phones, mobile terminals, cameras, watches, laptops, displays, lighting, traffic lights, automotive lamps, and display components for home appliances and optical devices.

[0095] The present inventors currently consider the best mode of the present invention to be one that embodies the preferred ranges of each of the above-mentioned requirements, and representative examples thereof will be described in the following examples. However, the present invention is not limited to these forms. [Example]

[0096] The present invention will be further explained below with reference to examples, but is not limited to these examples.

[0097] The details of the components used and the evaluation are as follows: (Component A) A: Bisphenol A aromatic polycarbonate resin (Teijin: CM-1000, viscosity average molecular weight 15,400) (B component) B: Pentaerythritol tetrakis(3-laurylthiopropionate) (Sumitomo Chemical Co., Ltd.: Sumilizer TP-D) (C component) C-1: Polycaprolactone tetraol, number average molecular weight 1,000 (Daicel Corporation "Placcel 410") C-2: Polycaprolactone triol, number average molecular weight 2,000 (Daicel Corporation "Placcel 320") C-3: Polycaprolactone diol, number average molecular weight 1,000 (Daicel Corporation "Placcel 210") C-4: Polycaprolactone diol, number average molecular weight 4,000 (Daicel Corporation "Placcel 240") C-5: Caprolactone polymer, number average molecular weight 10,000 (Daicel Corporation "Placcel H1P") (Other ingredients) (antioxidant) D: Hindered phenol antioxidant (BASF: Irganox 1076) (mold release agent) E: Glycerin monostearate (Riken Vitamin Co., Ltd.: Rikemal S-100A) (Evaluation method)

[0098] (1) Spectral light transmittance Pellets obtained from each composition of the examples were dried in a hot air circulating dryer at 120°C for 5 hours and molded into molded plates measuring 50 mm in width, 90 mm in length, and 2 mm in thickness using an injection molding machine [J85-ELIII manufactured by The Japan Steel Works, Ltd.] at a molding temperature of 270°C and a mold temperature of 80°C. The spectral transmittance of this 2 mm-thick molded plate was measured using a spectrophotometer [Cary 5000 manufactured by Agilent Technologies] in the wavelength range of 200 nm to 800 nm at 1 nm intervals. The average spectral transmittance in the wavelength range of 340 nm to 420 nm was calculated from the obtained spectral transmittance. A higher spectral light transmittance indicates less light attenuation and better light-guiding performance. A spectral light transmittance of 86.0% or more was evaluated as ◯, and a value of less than 86.0% was evaluated as ×.

[0099] (2) Molded plate hue Pellets obtained from each composition of the examples were dried in a hot air circulating dryer at 120°C for 5 hours and molded into plates 50 mm wide, 90 mm long, and 2 mm thick using an injection molding machine [J85-ELIII manufactured by The Japan Steel Works, Ltd.] at a molding temperature of 270°C and a mold temperature of 80°C. The hue (L*, a*, b*) of these 2 mm thick plates was measured using an integrating sphere spectrophotometer [CE-7000A manufactured by X-Rite] in accordance with JIS-K7105 under the conditions of a D65 light source, a 10-degree viewing angle, and transmission. The higher the b* value of the molded plate, the more likely the molded plate is to turn yellow. A b* value of 0.4 or less is marked as ◯, and a value exceeding 0.4 is marked as ×.

[0100] (3) Moisture and heat resistance Pellets obtained from each composition of the examples were dried in a hot air circulating dryer at 120°C for 5 hours and molded into molded plates measuring 50 mm wide, 90 mm long, and 2 mm thick using an injection molding machine [Japan Steel Works, Ltd. J85-ELIII] at a molding temperature of 270°C and a mold temperature of 80°C. These molded plates were subjected to a moist heat treatment (temperature 120°C, 24 hours) using a steam sterilizer [Yamato Scientific Co., Ltd. SN-510], and the haze and viscosity average molecular weight (Mv) were measured before and after the moist heat treatment. The haze of the molded plates was measured according to JIS-K7361-1, and the viscosity average molecular weight (Mv) was measured using the following method.

[0101] Viscosity average molecular weight (Mv) measurement The specific viscosity (η SP ) was measured using an Ostwald viscometer from a solution of polycarbonate resin dissolved in 100 ml of methylene chloride at 20°C, and the calculated specific viscosity (η SP ) and the viscosity average molecular weight Mv was calculated using the following formula: Specific viscosity (η SP )=(t-t0) / t0 [t0 is the number of seconds that methylene chloride falls, and t is the number of seconds that the sample solution falls] η SP / c=[η]+0.45×[η] 2 c (where [η] is the intrinsic viscosity) [η]=1.23×10 -4 Mv 0.83 c=0.7

[0102] The higher the haze after moist heat treatment, the lower the transparency of the molded plate, and the greater the decrease in viscosity average molecular weight after moist heat treatment, the more susceptible the resin is to hydrolysis. The increase in haze before and after moist heat treatment is expressed as ΔHaze, with ΔHaze of 1.5 or less being rated as O and anything over 1.5 being X. The decrease in Mv before and after moist heat treatment is also expressed as ΔMv, with ΔMv of 1,000 or less being rated as O and anything over 1,000 being X.

[0103] [Examples 1 to 8 and Comparative Examples 1 to 4] Components A, B, C, and other components were mixed in a blender in the amounts shown in Table 1, and then melt-kneaded using a vented twin-screw extruder to obtain pellets. The vented twin-screw extruder used was a TEX30α (fully intermeshing, co-rotating, double-start screws) manufactured by The Japan Steel Works, Ltd. The extrusion conditions were a discharge rate of 30 kg / h, a screw rotation speed of 270 rpm, a vent vacuum of 1 kPa, and an extrusion temperature of 260°C. The evaluation results are shown in Table 1.

[0104] [Table 1] [Industrial Applicability]

[0105] The polycarbonate resin composition of the present invention has excellent light conductivity and is less prone to yellowing during molding or deterioration in a humid and hot environment. Molded articles obtained from the polycarbonate resin composition are suitable for a variety of industrial applications, including in the fields of LED lighting, office automation equipment, electrical and electronic equipment, and automobiles. Extremely useful.

Claims

1. A polycarbonate resin composition having light-guiding properties, comprising 100 parts by weight of (A) polycarbonate resin (component A), 0.005 to 0.2 parts by weight of (B) a thioether-based compound (component B), and 0.2 to 1.5 parts by weight of (C) a caprolactone-based polymer (component C) having a number average molecular weight of 300 to 8,000, wherein component B is a thioether-based compound represented by the following formula [1] or the following formula [2]: (R 1 -S-CH 2 -CH 2 -C(O)O-CH 2 ) 4 -C [1] [In formula [1], R 1 s may be the same or different and represent a linear or branched alkyl group having 4 to 20 carbon atoms.] (R 2 -O-C(O)-CH 2 -CH 2 -) 2 -S [2] [In formula [2], R 2 s may be the same or different and represent a linear or branched alkyl group having 6 to 22 carbon atoms.]

2. 2. The polycarbonate resin composition having light-guiding properties according to claim 1, wherein the thioether compound of component B is at least one thioether compound selected from the group consisting of dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, and pentaerythritol tetrakis(3-laurylthiopropionate).

3. 3. The polycarbonate resin composition having light-guiding properties according to claim 1, wherein component C is at least one caprolactone polymer selected from the group consisting of bifunctional polycaprolactone diols, trifunctional polycaprolactone triols, and tetrafunctional polycaprolactone tetraols represented by the following formulas [3] to [5]: 【Chemical 1】 (wherein m+n is an integer of 3 or more and 35 or less, and R is C ２ H ４ , C ２ H ４ O.C. ２ H ４ , or C(CH ３ ) ２ (CH ２ ) ２ is) 【Chemistry 2】 (wherein l+m+n is an integer of 3 or more and 35 or less, and R is CH ２ CHCH ２ , C.H. ３ C(CH ２ ) ３ , or C.H. ３ CH ２ C(CH ２ ) ３ is) 【Chemistry 3】 (wherein k+l+m+n is an integer of 4 or more and 35 or less, and R is C(CH ２ ) ４ is)

4. 4. The polycarbonate resin composition having light-guiding properties according to claim 1, wherein the caprolactone polymer of component C has a number average molecular weight of 500 to 5,000.

5. A molded article made of the polycarbonate resin composition having light-guiding properties according to any one of claims 1 to 4.

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