Polycarbonate resin composition and molded article thereof

Abstract

This polycarbonate resin composition has a light-guiding capability and is characterized by containing, per 100 parts by weight of (A) a polycarbonate resin (component A), (B) 0.01 to 0.1 parts by weight of a pentaerythritol diphosphite compound (component B) represented by formula [1], and (C) 0.2 to 1.5 parts by weight of a caprolactone-based polymer (component C) having a number-average molecular weight of at least 300 and less than 4,000. The resin composition is further characterized by having excellent light-guiding properties, exhibiting little yellowing in a high-temperature, dry-heat environment, and not exhibiting a substantial loss of heat resistance.

Description

Polycarbonate resin composition and molded article thereof

[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 in a high-temperature, dry-heat environment, and good heat resistance, and suitable for use in optical elements such as light-guiding plates, display panels, lighting covers, and the like, and a molded article made thereof.

[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 life span, 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, mainly for spot lighting.In addition, with regard to surface light sources such as displays, LED light sources have the advantage that the color purity of the light emitted by RGB three-color LEDs is higher than the colors (red, green, and blue) obtained by transmitting white light emitted by cold cathode fluorescent lamps through color filters, and the range of color reproduction can be greatly expanded, so LED light sources are being increasingly used.

[0003] On the other hand, because LEDs are point light sources, in order to illuminate a wide area, it is necessary to install many LEDs on the back of the light source body (backlight system), 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 so-called edge light system light sources in which LEDs are placed on the edge surface of the light source body.

[0004] Edge-lit light sources use light guides that 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 in distance. Therefore, materials for light-guiding molded articles are required to have low attenuation of light from the light source, i.e., light-guiding properties. Among transparent resins, polymethyl methacrylate (PMMA) has been used as the most suitable material. 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 resistance 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 the moisture and heat resistance, which limits the 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 having a light scattering layer provided on the front or back surface of a plate-shaped molded product formed using a resin composition consisting of polycarbonate and an acrylic resin. Patent Document 5 reports an aromatic polycarbonate resin composition consisting of an aromatic polycarbonate resin and another thermoplastic resin having a refractive index difference of 0.001 or more with the aromatic polycarbonate resin. However, because an acrylic resin, which is inherently incompatible with polycarbonate resin, is added, the amount added is limited, and there are cases in which the light guide property is not 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 long-term heat resistance. However, neither of these compositions satisfied both the light-guiding properties and the hue.

[0009] Japanese Patent Application Laid-Open No. 2007-204737 Japanese Patent Application Laid-Open No. 2004-250557 Japanese Patent Application Laid-Open No. 2015-157901 Japanese Patent Application Laid-Open No. 10-73725 Japanese Patent Application Laid-Open No. 2002-60609 Japanese Patent Application Laid-Open No. 2007-131679 International Publication No. 2016 / 199783

[0010] An object of the present invention is to provide a polycarbonate resin composition which has excellent light-transmitting properties, is less prone to yellowing in a high-temperature, dry-heat environment, and does not suffer from a significant loss in heat resistance, and to provide a molded article made from the same.

[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 comprising a polycarbonate resin, a phosphorus-based antioxidant, and a caprolactone-based polymer having a specific molecular weight in a specific proportion, and have arrived at the present invention.

[0012] That is, according to the present invention, the following configurations (1) to (7) are provided.

[0013] (1) A polycarbonate resin composition having light-guiding properties, characterized by containing, relative to 100 parts by weight of (A) a polycarbonate resin (component A), (B) 0.01 to 0.1 parts by weight of a pentaerythritol diphosphite compound (component B) represented by the following formula [1], and (C) 0.2 to 1.5 parts by weight of a caprolactone-based polymer (component C) having a number-average molecular weight of 300 or more and less than 4,000:

[0014]

[0015] (2) The polycarbonate resin composition having light-guiding properties according to the above item (1), wherein the 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 [2] to [4]:

[0016]

[0017] (wherein m+n is an integer of 3 or more and 33 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)

[0018]

[0019] (wherein l+m+n is an integer of 3 or more and 33 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)

[0020]

[0021] (wherein k+l+m+n is an integer of 4 or more and 33 or less, and R is C(CH ２ ) ４ (3) The polycarbonate resin composition having light-guiding properties according to the above (1) or (2), wherein the caprolactone polymer of component C has a number-average molecular weight of 500 to 3,000.

[0022] (4) A polycarbonate resin composition having light-guiding properties according to any one of the preceding paragraphs (1) to (3), which contains 0.001 to 0.1 parts by weight of (D) a phosphorus-based antioxidant other than component B (component D) per 100 parts by weight of (A) polycarbonate resin (component A).

[0023] (5) The polycarbonate resin composition having light-guiding properties according to any one of the preceding paragraphs (1) to (4), which contains 0.01 to 1 part by weight of (E) a mold release agent (Component E) per 100 parts by weight of (A) a polycarbonate resin (Component A).

[0024] (6) A polycarbonate resin composition having light-guiding properties according to any one of the preceding items (1) to (5), which contains 0.001 to 0.2 parts by weight of an epoxy compound (F) (component F) per 100 parts by weight of a polycarbonate resin (A) (component A).

[0025] (7) A molded article made of the polycarbonate resin composition having light-guiding properties described in any one of (1) to (6) above.

[0026] The polycarbonate resin composition of the present invention exhibits excellent light-guiding properties, good heat resistance, and dry heat resistance. Because the polycarbonate resin composition of the present invention has the above-mentioned effects, it is suitable for use as a light-guiding molded article and is extremely useful in various industrial applications, such as in the fields of lighting (including LED lighting), office automation equipment, electrical and electronic equipment, and automobiles, and the industrial effects it offers are extremely significant. Specific examples include lighting covers, display diffusers, glass replacement applications, various optical disks and related components, various housing molded articles such as battery housings, lens barrels, memory cards, speaker cones, disk cartridges, surface light emitters, mechanical parts for micromachines, molded articles with hinges or molded articles for hinges, light-transmitting / light-guiding buttons, and touch panel parts.

[0027] The present invention will be described in detail below. <Component A: Polycarbonate Resin> The polycarbonate resin used as component A of the present invention is usually one obtained by reacting a dihydroxy compound with a carbonate precursor by an interfacial polycondensation method or a melt transesterification method, or one obtained by polymerizing a carbonate prepolymer by a solid-phase transesterification method, or one obtained by polymerizing a cyclic carbonate compound by a ring-opening polymerization method.

[0028] The dihydroxy component used here may be any dihydroxy component that is normally used as a dihydroxy component in polycarbonate resins, and may be a bisphenol or an aliphatic diol.

[0029] 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)diphenylmethane, 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,Examples include 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 compounds having a siloxane structure represented by the following formula [5]:

[0030]

[0031] [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 １０are 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.] 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{( 2,2-bis{(2-hydroxyethoxy)phenyl}propane, 2,2-bis{(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}diphenylmethane, 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, 1,4-bis[2-{(2-hydroxyethoxy)phenyl}propyl]benzene, 1,4-bis{(2-hydroxyethoxy)phenyl}cyclohexane, 1,3-bis{(2-hydroxyethoxy)phenyl}cyclohexane, 4, Examples of such esters include 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 particularly 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 ...1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3 Preferred are 2,2-bis(4-hydroxyphenyl)fluorene, 1,3-bis{2-(4-hydroxyphenyl)propyl}benzene, 1,4-bis{2-(4-hydroxyphenyl)propyl}benzene, and the bisphenol compounds represented by the above general formula [5], and particularly 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, and the bisphenol compounds represented by the above general formula [5]. Of these, 2,2-bis(4-hydroxyphenyl)propane is most preferred because of its excellent strength and good durability. These may be used alone or in combination of two or more.

[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 the tri- or higher functional polyfunctional aromatic compound used in such a branched polycarbonate resin 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. A catalyst, such as a tertiary amine or a quaternary ammonium salt, can also be used to promote the reaction. 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 proportion of aromatic dihydroxy components with the carbonate diester under heating in an inert gas atmosphere, and distilling off the resulting alcohol or phenols. 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 phenols. A catalyst typically used in transesterification reactions can also be used to promote the reaction. 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, it is preferable to use a terminal terminator 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 one without the terminals being blocked. Examples of such terminal terminators include monofunctional phenols represented by the following formulas [6] to [8].

[0037]

[0038] [In formula [6], A represents 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 represents an integer of 1 to 5, preferably 1 to 3].

[0039]

[0040]

[0041] [In the formulas [7] and [8], Y is -R-O-, -R-CO-O-, or -R-O-CO-, where R represents a single bond or a divalent aliphatic hydrocarbon group having 1 to 10, preferably 1 to 5, carbon atoms, and n represents an integer of 10 to 50.] Specific examples of the monofunctional phenols represented by the above formula [6] include phenol, isopropylphenol, p-tert-butylphenol, p-cresol, p-cumylphenol, 2-phenylphenol, 4-phenylphenol, and isooctylphenol.

[0042] Furthermore, the monofunctional phenols represented by the above formula [7] or [8] are phenols having a long-chain alkyl group or an aliphatic ester group as a substituent, and when they are used to block the ends of a polycarbonate resin, they not only function as an end terminator or molecular weight regulator, 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.

[0043] As the substituted phenols of the above formula [7], those in which n is 10 to 30, particularly 10 to 26, are preferred, and specific examples thereof include decylphenol, dodecylphenol, tetradecylphenol, hexadecylphenol, octadecylphenol, eicosylphenol, docosylphenol, and triacontylphenol.

[0044] As the substituted phenol of the above formula [8], a compound in which Y is —R—COO— and R is a single bond is 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.

[0045] Among these monofunctional phenols, the monofunctional phenols represented by the above formula [6] are preferred, more preferably alkyl-substituted or phenylalkyl-substituted phenols, and particularly preferably p-tert-butylphenol, p-cumylphenol or 2-phenylphenol.

[0046] 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 resulting polycarbonate resin. The end-capping agents may be used alone or in combination of two or more.

[0047] 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.

[0048] 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, even more preferably 13,500 to 35,000, and most preferably 15,000 to 30,000. A molecular weight exceeding 50,000 may result in excessively high melt viscosity, resulting in poor moldability, while a molecular weight below 11,500 may result in problems with mechanical strength. The viscosity average molecular weight referred to in the present invention is determined by first determining the specific viscosity calculated by the following formula using an Ostwald viscometer from a solution prepared by dissolving 0.7 g of polycarbonate resin in 100 ml of methylene chloride at 20°C, and then inserting the determined specific viscosity into the following formula to determine the viscosity average molecular weight Mv.

[0049] Specific viscosity (η ＳＰ ) = (t - t ０ ) / t ０ [t ０ is the number of seconds for methylene chloride to fall, and t is the number of seconds for the sample solution to fall] η ＳＰ / c = [η] + 0.45 × [η] ２ c (where [η] is the intrinsic viscosity) [η] = 1.23 × 10 －４ Mv ０．８３ The polycarbonate resin used as component A of the present invention preferably has a total Cl (chlorine) content of 0 to 500 ppm, more preferably 0 to 350 ppm. When the total Cl content in the polycarbonate resin is within the above range, excellent color and thermal stability are obtained, which is preferred.

[0050] <Component B: Pentaerythritol Diphosphite Compound> The pentaerythritol diphosphite used as Component B in the present invention is a pentaerythritol diphosphite compound having a specific structure represented by the following formula [1]: Polycarbonate resin compositions obtained by blending a phosphite compound of this structure and molded articles formed therefrom have excellent dry heat resistance and are inhibited from discoloring when exposed to a high-temperature, dry-heat environment.

[0051]

[0052] The content of the pentaerythritol diphosphite compound is 0.01 to 0.1 parts by weight, preferably 0.015 to 0.08 parts by weight, and more preferably 0.02 to 0.05 parts by weight, relative to 100 parts by weight of the polycarbonate resin. If the content is less than this range, the effect of inhibiting discoloration when exposed to a high-temperature, dry heat environment will be reduced, and if the content exceeds this range, the pentaerythritol diphosphite compound will volatilize when heat is applied during molding or other processing, and will adhere to the mold, causing defects in the molded product.

[0053] <Component C: Caprolactone Polymer> The caprolactone polymer used as Component C of the present invention improves the light-guiding performance of the polycarbonate resin composition, and when used in combination with Component B, it is possible to obtain a polycarbonate resin composition and a molded article formed therefrom that have excellent dry heat resistance. It also improves the thermal stability during molding processing, and improves the mechanical properties and color of the molded article.

[0054] The caprolactone polymer used as component C is a polymer of caprolactone, particularly ε-caprolactone, that is, a polymer having a repeating unit of (-CH ２ -CH ２ -CH ２ -CH ２ -CH ２ In the caprolactone polymer, some of the hydrogen atoms in the methylene chain or repeating units may be substituted with halogen atoms or hydrocarbon groups. The polycaprolactone may be terminated by esterification, etherification, or other terminal treatment.

[0055] The polycaprolactone structure may be not only a polycaprolactone diol such as a polymer of ε-caprolactone, but also a difunctional, trifunctional or tetrafunctional structure such as polycaprolactone triol or polycaprolactone tetraol.

[0056] 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 [2] to [4]:

[0057]

[0058] (wherein m+n is an integer of 3 or more and 33 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)

[0059]

[0060] (wherein l+m+n is an integer of 3 or more and 33 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)

[0061]

[0062] (wherein k+l+m+n is an integer of 4 or more and 33 or less, and R is C(CH ２ ) ４ The molecular weight of the caprolactone polymer used in the present invention is in the range of 300 or more but less than 4,000, preferably 500 to 3,000, and most preferably 1,000 to 2,000, in terms of number average molecular weight. If the caprolactone polymer has a number average molecular weight of 4,000 or more, it will be poorly dispersible in polycarbonate resin, and the effect of enhancing light guiding properties will be reduced, while if it is less than 300, it will have an adverse effect on the heat resistance of the polycarbonate resin.

[0063] 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 the lower limit, excellent light-guiding properties cannot be obtained, and if the content is more than the upper limit, heat resistance and mechanical strength are adversely affected.

[0064] <Other Components> 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 the other resins and fillers should be selected taking this into consideration.

[0065] 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. (I) Other Heat Stabilizers Various known heat stabilizers can be blended into the polycarbonate resin composition of the present invention. Specific examples include phosphorus-based antioxidants other than component B, sulfur-based antioxidants, and phenol-based antioxidants. Among these, phosphorus-based antioxidants other than component B are preferred.

[0066] 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.

[0067] 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, Examples of suitable phosphite compounds include bis(2,4-di-tert-butylphenyl)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, and dicyclohexyl pentaerythritol diphosphite. Furthermore, other phosphite compounds that 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.

[0068] Examples of the 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, tetrakis(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 ... Examples of the phosphonite include (2,4-di-tert-butylphenyl)-3-phenyl-phenyl phosphonite, bis(2,6-di-n-butylphenyl)-3-phenyl-phenyl phosphonite, bis(2,6-di-tert-butylphenyl)-4-phenyl-phenyl phosphonite, and bis(2,6-di-tert-butylphenyl)-3-phenyl-phenyl phosphonite. Of these, tetrakis(di-tert-butylphenyl)-biphenylene diphosphonite and bis(di-tert-butylphenyl)-phenyl-phenyl phosphonite are preferred, and tetrakis(2,4-di-tert-butylphenyl)-biphenylene diphosphonite and bis(2,4-di-tert-butylphenyl)-phenyl-phenyl phosphonite are more preferred.

[0069] Examples of the phosphine compound include triethylphosphine, tripropylphosphine, tributylphosphine, trioctylphosphine, triamylphosphine, dimethylphenylphosphine, dibutylphenylphosphine, diphenylmethylphosphine, diphenyloctylphosphine, triphenylphosphine, tris(p-tolyl)phosphine, tris(p-anisyl)phosphine, trinaphthylphosphine, and diphenylbenzylphosphine. A particularly preferred phosphine compound is triphenylphosphine.

[0070] Examples of the phosphonate compound include dimethyl benzenephosphonate, diethyl benzenephosphonate, and dipropyl benzenephosphonate.

[0071] 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.

[0072] The above-mentioned phosphorus-based antioxidants can be used alone or in combination of two or more kinds, and among them, phosphine compounds are preferred.

[0073] From the viewpoint of heat resistance and the like, the content of the phosphorus-based antioxidant other than Component B is preferably 0.001 to 0.1 parts by weight, more preferably 0.005 to 0.05 parts by weight, and even more preferably 0.01 to 0.03 parts by weight, relative to 100 parts by weight of the polycarbonate resin.

[0074] (II) Mold Release Agents The polycarbonate resin composition of the present invention can be blended with a mold release agent 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-containing oils are preferred. Particularly preferred mold release agents include saturated fatty acid esters, such as 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.

[0075] The amount of the release agent to be added is preferably in the range of 0.01 to 1 part by weight, more preferably 0.015 to 0.5 parts by weight, and even more preferably 0.02 to 0.3 parts by weight, per 100 parts by weight of the polycarbonate resin (A).

[0076] (III) Ultraviolet Absorber The polycarbonate resin composition of the present invention can be blended with 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.

[0077] 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.

[0078] 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 malonate ester compounds typified by 2-(1-arylalkylidene)malonic acid esters such as Hostavin PR-25 manufactured by Clariant Japan K.K. and Hostavin B-CAP manufactured by Clariant Japan K.K.

[0079] The content of the ultraviolet absorber is preferably 0.01 to 5 parts by weight, more preferably 0.02 to 1 part by weight, based on 100 parts by weight of the polycarbonate resin.

[0080] (IV) Light Stabilizer The polycarbonate resin composition of the present invention may contain a light stabilizer, if necessary.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, more preferably 0.02 to 1 part by weight, based on 100 parts by weight of the polycarbonate resin.

[0081] (V) Bluing Agents A bluing agent can be blended into the polycarbonate resin composition of the present invention to counteract the yellowish tint caused by ultraviolet absorbers and the like. Any bluing agent typically used in polycarbonate resins can be used without any particular problems. Generally, anthraquinone dyes are readily available and are preferred. Specific bluing agents include, for example, Solvent Violet 13 (CA. No. (Color Index No.) 60725; trade names: "Macrolex Violet B" manufactured by Bayer, "Diaresin Blue G" manufactured by Mitsubishi Chemical Corporation, and "Sumiplast Violet B" manufactured by Sumitomo Chemical Co., Ltd.), Solvent Violet 31 (CA. No. 68210; trade name: "Diaresin Violet D" manufactured by Mitsubishi Chemical Corporation), and Solvent Violet 33 (CA. No. 60725; trademark "Diaresin Blue J" manufactured by Mitsubishi Chemical Corporation], generic name Solvent Blue 94 [CA. No. 61500; trademark "Diaresin Blue N" manufactured by Mitsubishi Chemical Corporation], generic name Solvent Violet 36 [CA. No. 68210; trademark "Macrolex Violet 3R" manufactured by Bayer], generic name Solvent Blue 97 [trademark "Macrolex Blue RR" manufactured by Bayer], and generic name Solvent Blue 45 [CA. No. 61110; trademark "Telazol Blue RLS" manufactured by Sandoz], with Macrolex Blue RR, Macrolex Violet B, and Telazol Blue RLS being particularly preferred. The content of the bluing agent is preferably 0.000005 to 0.001 part by weight, more preferably 0.00001 to 0.0001 part by weight, based on 100 parts by weight of the polycarbonate resin.

[0082] (VI) Fluorescent Brightening Agent In the polycarbonate resin composition of the present invention, the fluorescent brightening agent 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." The fluorescent brightening agent absorbs ultraviolet energy in light and radiates this energy in the visible region. The content of the fluorescent brightening agent 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 the polycarbonate resin.

[0083] (VII) Epoxy Compounds An epoxy compound can be blended into the polycarbonate resin composition of the present invention, if necessary. Such epoxy compounds are blended for the purpose of inhibiting mold corrosion, and basically any epoxy compound having an 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, a copolymer of methyl methacrylate and glycidyl methacrylate, and a copolymer of styrene and glycidyl methacrylate.

[0084] The amount of the epoxy compound to be blended is preferably 0.001 to 0.2 parts by weight, more preferably 0.003 to 0.15 parts by weight, and even more preferably 0.005 to 0.1 parts by weight, per 100 parts by weight of the polycarbonate resin.

[0085] (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, and 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 these 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.

[0086] Alkali metals constituting the metal salts include lithium, sodium, potassium, rubidium, and cesium, while 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, the alkali metals in the alkali metal sulfonates can be selected appropriately, but 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 composed of other alkali metals.

[0087] Specific examples of alkali metal salts of perfluoroalkylsulfonates 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, cesium perfluorooctane sulfonate, cesium perfluorohexanesulfonate, rubidium perfluorobutanesulfonate, and rubidium perfluorohexanesulfonate, and these can be used alone or in combination of two or more. Here, the number of carbon atoms in the perfluoroalkyl group is preferably in the range of 1 to 18, more preferably in the range of 1 to 10, and even more preferably in the range of 1 to 8. Among these, potassium perfluorobutanesulfonate is particularly preferred.

[0088] Perfluoroalkylsulfonic acid alkali (earth) metal salts made from alkali metals usually contain a considerable amount of fluoride ions. The presence of such fluoride ions can reduce flame retardancy, so it is preferable to reduce them 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 preferable. Such perfluoroalkylsulfonic acid alkali (earth) metal salts with reduced fluoride ion content can be produced using known production methods, including a method of reducing the amount of fluoride ions contained in raw materials when producing a fluorine-containing organometallic salt, a method of removing hydrogen fluoride and the like obtained by the reaction by heating or using gas generated during the reaction, and a method of reducing the amount of fluoride ions using a purification method such as recrystallization or reprecipitation when producing a fluorine-containing organometallic salt. In particular, since organic metal salt flame retardants are relatively soluble in water, it is preferable to use ion-exchanged water, particularly water having an electrical resistance of 18 MΩ cm or more, i.e., an electrical conductivity of approximately 0.55 μS / cm or less, and to dissolve and wash the flame retardant at a temperature higher than room temperature, followed by cooling and recrystallization to produce the flame retardant.

[0089] Specific examples of the alkali (earth) metal salt of aromatic sulfonate 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.

[0090] 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 such sulfates of monohydric 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. Examples of alkali(earth) metal salts of these sulfates include alkali(earth) metal salts of lauryl sulfate. Examples of alkali (earth) metal salts of aromatic sulfonamides include alkali (earth) metal salts of saccharin, N-(p-tolylsulfonyl)-p-toluenesulfonimide, N-(N'-benzylaminocarbonyl)sulfanilimide, and N-(phenylcarboxyl)sulfanilimide.

[0091] 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 the polycarbonate resin.

[0092] (IX) Others In addition to the above, the resin composition of the present invention can be blended with known additives to impart various functions to the molded product or improve its properties, as long as the purpose of the present invention is 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., titanium oxide fine particles, zinc oxide fine particles), light diffusing agents, flow modifiers, radical generators, infrared absorbers (heat ray absorbers), and photochromic agents.

[0093] <Regarding 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 can be thoroughly mixed using a premixing device such as a V-type blender, a Henschel mixer, a mechanochemical device, or an 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 pelletizing using equipment such as a pelletizer. 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 a portion of component A and the other components, and then feeding the remaining components to the melt mixer independently, 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] <Production of Molded Articles> 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, a Banbury mixer, a roll, or the like, and then molded by a conventional method such as injection molding, extrusion molding, or compression molding to obtain a molded article. Furthermore, a light source can be provided on at least one side of a light-guiding molded plate obtained by molding into a plate, and a reflector can be attached to one side of the molded plate to form a surface light source. As the light source for such a surface light source, a fluorescent lamp or a self-luminous element such as a cold cathode tube, an LED, a laser diode, or an organic electroluminescent device can be used. The light-guiding molded plate and surface light source obtained by the present invention can be used in mobile phones, mobile terminals, cameras, watches, laptop computers, 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 a combination of the preferred ranges of each of the above-mentioned requirements, and representative examples thereof will be described in the following examples, although the present invention is not limited to these modes.

[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 type aromatic polycarbonate resin (manufactured by Teijin Limited: CM-1000, viscosity average molecular weight 15,400) (Component B) B: Pentaerythritol diphosphite compound (manufactured by Asahi Denka Kogyo Co., Ltd.: Adekastab PEP-36) (Component C) C-1: Polycaprolactone tetraol, number average molecular weight 1,000 (manufactured by Daicel Corporation: "Placcel 410") C-2: Polycaprolactone triol, number average molecular weight 2,000 (manufactured by Daicel Corporation: "Placcel 320") C-3: Polycaprolactone diol, number average molecular weight 1,000 (manufactured by Daicel Corporation: "Placcel 210") C-4 (Comparative example): Caprolactone polymer, number average molecular weight 10,000 (manufactured by Daicel Corporation: "Placcel H1P") (Other Components) (Heat Stabilizers) D: Triphenylphosphine (JC-263 manufactured by Johoku Chemical Industry Co., Ltd.) (mold release agent) E: Glycerin monostearate (Rikemal S-100A manufactured by Riken Vitamin Co., Ltd.) (epoxy compound) F: Polyfunctional alicyclic epoxy resin (EHPE3150 manufactured by Daicel Corporation)

[0098] (Evaluation Method) (1) Spectral Light Transmittance Pellets obtained from each composition of the Examples were dried in a hot air circulation dryer at 120°C for 5 hours and molded into a molded plate having a width of 50 mm, a length of 90 mm, and a thickness of 2 mm 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 light transmittance of this 2 mm thick molded plate was measured at 1 nm intervals in the wavelength range of 200 nm to 800 nm using a spectrophotometer [Cary 5000 manufactured by Agilent Technologies]. The average spectral light transmittance in the wavelength range of 340 nm to 420 nm was calculated from the obtained spectral light transmittance. A higher spectral light transmittance value indicates less light attenuation and better light-guiding performance. A spectral light transmittance of 88.0% or more was rated as ◯, and a spectral light transmittance of less than 88.0% was rated as ×.

[0099] (2) Dry Heat Resistance (Thermal Stability) Evaluation The pellets obtained from each composition of the examples were dried in a hot air circulating dryer at 120 ° C for 5 hours, and then molded into a molded plate having a width of 50 mm, a length of 90 mm, and a thickness of 2 mm using an injection molding machine [J85-ELIII manufactured by Japan Steel Works, Ltd.] at a molding temperature of 270 ° C and a mold temperature of 80 ° C. This molded plate was heat-treated for 1,000 hours in a hot air circulating dryer at 130 ° C. The yellowness index (YI) of the molded plate before and after heat treatment was measured in accordance with ASTM-D1925 using an integrating sphere spectrophotometer [CE-7000A manufactured by X-Rite]. The increase in YI of the molded plate after heat treatment (ΔYI) was calculated using the following formula, and dry heat resistance was evaluated. The larger the ΔYI, the more likely it was to yellow and the poorer the dry heat resistance. ΔYI of 6.0 or less was rated as ◯, and that of more than 6.0 was rated as ×. ΔYI = YI after heat treatment - YI before heat treatment

[0100] (3) Evaluation of Heat Resistance (Deflection Temperature Under Load) Pellets obtained from each composition of the Examples were dried in a hot air circulation dryer at 120°C for 5 hours, and the deflection temperature under load was measured in accordance with ISO 75-1 and ISO 75-2 using an injection molding machine [J180ADS-110U manufactured by The Japan Steel Works, Ltd.] at a molding temperature of 270°C and a mold temperature of 70°C (test piece shape: length 80mm x width 10mm x thickness 4mm, load: 1.80MPa, measuring machine: HDT tester "3M-2" manufactured by Toyo Seiki Seisaku-sho). Those with a deflection temperature under load of 118°C or higher were marked with a "good" and those with a deflection temperature below 118°C were marked with a "bad".

[0101] [Examples 1 to 6 and Comparative Examples 1 to 4] Component A, component B, component 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, two-start screw) 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.

[0102]

[0103] The polycarbonate resin composition of the present invention has excellent light conductivity and exhibits good heat resistance and dry heat resistance, and molded articles obtained from the polycarbonate resin composition are suitably used as light-guiding molded articles and are extremely useful in various industrial applications, such as the fields of lighting including LED lighting, office automation equipment, electrical and electronic equipment, and automobiles. Specific examples include lighting covers, display diffusers, glass replacement applications, various optical disks and related components, various housing molded articles such as battery housings, lens barrels, memory cards, speaker cones, disk cartridges, surface light emitters, mechanical parts for micromachines, molded articles with hinges or molded articles for hinges, light-transmitting / light-guiding buttons, and touch panel parts.

Claims

1. A polycarbonate resin composition having light-guiding properties, characterized by containing, relative to 100 parts by weight of (A) polycarbonate resin (component A), (B) 0.01 to 0.1 parts by weight of a pentaerythritol diphosphite compound (component B) represented by the following formula [1], and (C) 0.2 to 1.5 parts by weight of a caprolactone-based polymer (component C) having a number-average molecular weight of 300 or more and less than 4,000.

2. A 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 [2] to [4]: (wherein m+n is an integer of 3 or more and 33 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) (wherein l+m+n is an integer of 3 or more and 33 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) (wherein k+l+m+n is an integer of 4 or more and 33 or less, and R is C(CH ２ ) ４ is) 3. 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 3,000.

4. A polycarbonate resin composition having light-guiding properties according to claim 1, containing 0.001 to 0.1 parts by weight of (D) a phosphorus-based antioxidant other than component B (component D) per 100 parts by weight of (A) polycarbonate resin (component A).

5. A polycarbonate resin composition having light-guiding properties according to claim 1, which contains 0.01 to 1 part by weight of (E) a mold release agent (component E) per 100 parts by weight of (A) a polycarbonate resin (component A).

6. A polycarbonate resin composition having light-guiding properties according to claim 1, which contains 0.001 to 0.2 parts by weight of (F) epoxy compound (component F) per 100 parts by weight of (A) polycarbonate resin (component A).

7. A molded article made of the polycarbonate resin composition having light-guiding properties described in any one of claims 1 to 6.