Polycarbonate resin composition

Abstract

This polycarbonate resin composition is characterized by containing 0.01-4 parts by mass of a polylactone-polyether copolymer (B) with respect to 100 parts by mass of a polycarbonate resin (A).

Description

Polycarbonate resin composition

[0001] The present invention relates to a polycarbonate resin composition, and more particularly to a polycarbonate resin composition which has a good hue, excellent transparency, and produces very little gas generation and mold contamination during molding, and to a molded article molded from the same.

[0002] Liquid crystal display devices used in personal computers, mobile phones, etc. incorporate planar light source devices to meet the demands for thinner, lighter, more energy-efficient, and higher-definition displays. These planar light source devices are equipped with a wedge-shaped light guide plate with a uniformly inclined surface or a flat light guide plate to guide incoming light uniformly and efficiently to the liquid crystal display. Some light guide plates have a textured surface to provide a light-scattering function.

[0003] Such light guide plates are obtained by injection molding of thermoplastic resin, and the above-mentioned uneven pattern is imparted by transferring unevenness formed on the surface of a nesting mold. Light guide plates have traditionally been molded from resin materials such as polymethyl methacrylate (PMMA), but in recent years, there has been a demand for display devices that can project clearer images, and the heat generated near the light source tends to cause the inside of devices to become hotter, so light guide plates are being replaced with more heat-resistant polycarbonate resin materials.

[0004] Polycarbonate resin has excellent mechanical properties, thermal properties, electrical properties, and weather resistance, but its light transmittance is lower than that of PMMA, etc., so when a surface light source is constructed from a light guide plate made of polycarbonate resin and a light source, the brightness is low. Furthermore, there has been a recent demand for reducing the chromaticity difference between the light entrance part of the light guide plate and a location away from the light entrance part, but polycarbonate resin has the problem of being more prone to yellowing than PMMA.

[0005] In order to improve transmittance and hue, Patent Document 1 proposes blending a polyalkylene glycol composed of a linear alkyl group into a polycarbonate resin. Blending polytetramethylene ether glycol improves transmittance and yellowing index (YI).

[0006] In particular, in recent mobile devices such as smartphones and tablet terminals, optical components such as light guide plates have become thinner and larger at a remarkable rate, requiring high barrel temperatures and high-speed injection molding for light guide plate molding. This has led to problems such as increased gas generation during molding, which can easily lead to mold contamination. Therefore, resin compositions used in these molding processes are required to not only have excellent hue (YI) and transparency, but also to minimize mold contamination due to gas generation during high-temperature injection molding and to have excellent impact resistance. Furthermore, particularly in the case of edge-lit light guide plates, monitors have become significantly larger, thinner, and more highly functional, requiring further improvements in the transparency, hue, and mold contamination resistance of light guide plates.

[0007] Patent No. 5699188

[0008] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a polycarbonate resin composition which has a good hue, is excellent in transparency, generates very little gas and causes little mold contamination during molding, and has excellent impact resistance.

[0009] The present inventors have conducted extensive research to achieve the above object and have discovered that by blending a specific amount of a polylactone-polyether copolymer with a polycarbonate resin, a polycarbonate resin composition can be obtained that has a good hue, excellent transparency, extremely little gas generation and mold contamination during molding, and excellent impact resistance, and have thus completed the present invention. The present invention relates to the following polycarbonate resin composition and molded article.

[0010] 1. A polycarbonate resin composition comprising 0.01 to 4 parts by mass of a polylactone-polyether copolymer (B) per 100 parts by mass of a polycarbonate resin (A). 2. The polycarbonate resin composition according to 1 above, wherein the polylactone-polyether copolymer (B) has a molar ratio of polylactone units to polyether units of 5:95 to 95:5. 3. The polycarbonate resin composition according to 1 or 2 above, wherein the polylactone-polyether copolymer (B) is a polycaprolactone-polyether copolymer.

[0011] 4. The polycarbonate resin composition according to any one of 1 to 3 above, wherein the polycaprolactone-polyether copolymer (B) is a polycaprolactone-polyether copolymer represented by the following general formula (I) or (II): (In formulas (I) and (II), R1 to R4 each represent a linear or branched hydrocarbon group having 2 to 20 carbon atoms which may be substituted with an aryloxy group or an alkoxy group, and R5 represents a CH ２ CHCH ２ , C.H. ３ C(CH ２ ) ３ , or C.H. ３ CH ２ C(CH ２ ) ３ a is an integer of 3 or greater, b and c are each an integer of 1 or greater, l, m and n are each an integer of 1 or greater, and o, p and q are each an integer of 1 or greater.) 5. The polycarbonate resin composition according to 4 above, wherein R1 to R4 in general formulas (I) and (II) are alkylene groups selected from the group consisting of a 1,2-ethylene group, a 1,2-propylene group, a trimethylene group, a 1,2-butylene group and a tetramethylene group.

[0012] 6. The polycarbonate resin composition according to any one of 1 to 5 above, wherein the polylactone-polyether copolymer (B) has a number average molecular weight (Mn) of 200 to 10,000. 7. The polycarbonate resin composition according to any one of 1 to 6 above, wherein the polycarbonate resin (A) has a viscosity average molecular weight (Mv) of 10,000 to 50,000. 8. The polycarbonate resin composition according to any one of 1 to 7 above, further comprising 0.005 to 0.5 parts by mass of a phosphorus-based stabilizer (C) per 100 parts by mass of the polycarbonate resin (A). 9. The polycarbonate resin composition according to 8 above, wherein the phosphorus-based stabilizer (C) is a phosphorus-based compound having a phosphite structure. 10. The polycarbonate resin composition according to any one of items 8 or 9 above, wherein the phosphorus-based stabilizer (C) comprises two or more phosphorus-based compounds having a phosphite structure, at least one of which is a phosphite-based stabilizer having a spiro ring skeleton. 11. The polycarbonate resin composition according to any one of items 1 to 10 above, further comprising 0.0005 to 0.2 part by mass of an epoxy compound and / or oxetane compound (D) per 100 parts by mass of the polycarbonate resin (A). 12. The polycarbonate resin composition according to any one of items 1 to 11 above, further comprising 0.01 to 0.5 part by mass of a fatty acid ester (E) per 100 parts by mass of the polycarbonate resin (A). 13. Pellets comprising the polycarbonate resin composition according to any one of items 1 to 12 above. 14. A molded article obtained by molding the pellets according to item 13 above. 15. The molded article according to item 14 above, which is an optical component.

[0013] The polycarbonate resin composition of the present invention has good hue, excellent transparency, extremely little gas generation and mold contamination during molding, and excellent impact resistance. Molded articles made from the polycarbonate resin composition of the present invention have a low YI value, excellent hue, and good transparency, making them particularly suitable as optical parts.

[0014] FIG. 1 is a plan view of a teardrop-shaped mold used in the evaluation of mold contamination in the examples.

[0015] The present invention will be described in detail below with reference to embodiments and examples. In this specification, unless otherwise specified, the term "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0016] The polycarbonate resin composition of the present invention is characterized by containing 0.01 to 4 parts by mass of a polylactone-polyether copolymer (B) per 100 parts by mass of a polycarbonate resin (A). Hereinafter, each component constituting the polycarbonate resin composition of the present invention, a molded article, etc. will be described in detail.

[0017] [Polylactone-Polyether Copolymer (B)] The polycarbonate resin composition of the present invention contains a polylactone-polyether copolymer (B). The polylactone-polyether copolymer (B) is a copolymer composed of units derived from a lactone compound and ether units or ether units derived from a polyglycol, and may be a random copolymer or a block copolymer, but is preferably a block copolymer composed of a polylactone block and a polyether block, and more preferably a block copolymer in which a polylactone is linked to the end of a polyether.

[0018] The molar ratio of polylactone units to polyether units in the polylactone-polyether copolymer (B) is preferably 5:95 to 95:5, more preferably 10:90 to 90:10, with polyether-rich copolymers having a molar ratio of polyether units of more than 50 being more preferred in terms of excellent hue, and the molar ratio of polylactone units to polyether units is preferably 10:90 to 45:55, 10:90 to 40:60, 10:90 to 35:65, and particularly preferably 10:90 to 30:70. The molar ratio of each unit in the polylactone-polyether copolymer (B) is measured using a 1H-NMR measurement device and 1,1,2,2-tetrachloroethylene-d2 as a solvent.

[0019] Examples of lactone compounds include cyclic lactone compounds such as ε-caprolactone, γ-butyrolactone, δ-valerolactone, β-propiolactone, and pivalolactone, which can be used alone or in combination. Of the lactone compounds, ε-caprolactone is particularly preferred.

[0020] The ether unit is represented by -[R １ -O]-, R １ R is a linear or branched hydrocarbon group having 2 to 20 carbon atoms which may be substituted with an aryloxy group or an alkoxy group. １ may be substituted with an aryloxy group or an alkoxy group, and may have an aromatic ring, such as a 1-phenoxymethyl group.

[0021] R １ is preferably a hydrocarbon group having 2 to 6 carbon atoms, particularly an alkylene group. Examples of the linear hydrocarbon group having 2 to 6 carbon atoms include a 1,2-ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. Examples of branched hydrocarbon groups having 2 to 6 carbon atoms include 1,2-propylene, 1,2-butylene, 2-methyl (1,2-propylene), 2,2-dimethyl (1,2-propylene), 1,2-dimethyl (1,2-propylene), 1-methyl (1,2-propylene), 1,2,2-trimethyl (1,2-propylene), 2-methyl (1,2-butylene), 1-methyl (1,2-butylene), 1-isopropylene (1,2-ethylene), 2-methyl, 1-isopropylene (1,2-ethylene), 1-tert-butyl (1,2-ethylene), 2-ethyl (1,2-butylene), 1-ethyl (1,2-butylene), 1,1-dimethyltrimethylene, 2-methyltetramethylene, and 1-methylpentylene. １ Among these, 1,2-ethylene group, 1,2-propylene group, trimethylene group, 1,2-butylene group and tetramethylene group are preferred, and 1,2-propylene group, trimethylene group and tetramethylene group are particularly preferred. １ may be the same hydrocarbon group or may be composed of different hydrocarbon groups.

[0022] The method for producing the polylactone-polyether copolymer (B) is not particularly limited, and the copolymer can be produced by a known method. For example, a method in which a lactone compound is subjected to ring-opening polymerization, followed by esterification copolymerization (block copolymerization) with the above-mentioned polyether glycol or alkylene oxide having an ether unit is desirable.

[0023] During copolymerization, a diol compound, a triol compound, etc. may be present. Examples of the diol compound include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-2-hexyl-1,3-propanediol, and cyclohexanedimethanol. Examples of the triol compound include glycerin, trimethylolethane, trimethylolpropane, butanetriol, pentanetriol, hexanetriol, heptanetriol, and octanetriol, and among these, glycerin and trimethylolpropane are preferred. When a triol compound is used, the polylactone-polyether copolymer (B) becomes a polymer having three branches.

[0024] The polycaprolactone-polyether copolymer (B) is preferably one represented by the following general formula (I) or (II). (In formulas (I) and (II), R1 to R4 each represent a linear or branched hydrocarbon group having 2 to 20 carbon atoms which may be substituted with an aryloxy group or an alkoxy group, and R5 represents a CH ２ CHCH ２ , C.H. ３ C(CH ２ ) ３ , or C.H. ３ CH２ C(CH ２ ) ３ a is an integer of 3 or more, b and c are each an integer of 1 or more, l, m, and n are each an integer of 1 or more, and o, p, and q are each an integer of 1 or more.

[0025] In general formulas (I) and (II), l, m, and n each represent an integer of 1 or more, preferably 1 to 100, more preferably 3 or more, even more preferably 5 or more, particularly preferably 10 or more, more preferably 90 or less, even more preferably 80 or less, among which 70 or less, 60 or less, 50 or less, 45 or less, 40 or less, and particularly preferably 35 or less. o, p, and q each represent an integer of 1 or more, preferably 1 to 100, more preferably 3 or more, even more preferably 5 or more, and particularly preferably 10 or more, more preferably 90 or less, even more preferably 80 or less, among which 70 or less, 60 or less, 50 or less, 45 or less, 40 or less, and particularly preferably 35 or less. a represents an integer of 3 or more, preferably 3 to 100, more preferably 3 or more, even more preferably 5 or more, and particularly preferably 10 or more, more preferably 90 or less, even more preferably 80 or less, among which 70 or less, 60 or less, 50 or less, 45 or less, 40 or less, and particularly preferably 35 or less. b and c are each an integer of 1 or more, preferably 1 to 100, more preferably 3 or more, even more preferably 5 or more, and particularly preferably 10 or more; more preferably 90 or less, even more preferably 80 or less, and among these, 70 or less, 60 or less, 50 or less, 45 or less, 40 or less, and particularly preferably 35 or less.

[0026] R1 to R4 are linear or branched hydrocarbon groups having 2 to 20 carbon atoms, which may be substituted with an aryloxy group or an alkoxy group. For example, they may have an aromatic ring, such as a 1-phenoxymethyl group. R1 to R4 are the same as the [R １ -O] R １ R1 to R3 are preferably alkylene groups selected from a 1,2-ethylene group, a 1,2-propylene group, a trimethylene group, a 1,2-butylene group, and a tetramethylene group. R5 is preferably CH ２ CHCH２ , C.H. ３ C(CH ２ ) ３ , or C.H. ３ CH ２ C(CH ２ ) ３ However, CH ２ CHCH ２ When l, m, and n are 2 or more, R1 to R3 may be the same hydrocarbon group or different hydrocarbon groups.

[0027] The number average molecular weight (Mn) of the polylactone-polyether copolymer (B) is preferably 200 to 10,000, more preferably 300 or more, even more preferably 500 or more, and more preferably 5,000 or less, even more preferably 4,500 or less. Having a number average molecular weight within this range ensures excellent compatibility with the polycarbonate resin (A), and tends to prevent gas generation during molding. If the number average molecular weight exceeds the upper limit, compatibility tends to decrease, while if the number average molecular weight is below the lower limit, gas generation during molding is likely to occur. The number average molecular weight (Mn) of the polylactone-polyether copolymer (B) is calculated based on the hydroxyl value measured in accordance with JIS K1577.

[0028] The content of the polylactone-polyether copolymer (B) is 0.01 to 4 parts by mass relative to 100 parts by mass of the polycarbonate resin (A). By including the polylactone-polyether copolymer (B) in such a range, the resulting polycarbonate resin composition has a good hue, excellent transparency, extremely little gas generation and mold contamination during molding, and excellent impact resistance without a decrease in impact resistance. The content is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more, and is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and even more preferably 1 part by mass or less. Whether the content of the polyether compound (B) is less than the above lower limit or exceeds the above upper limit, the color of the resulting molded article tends to be inferior.

[0029] [Polycarbonate Resin (A)] The polycarbonate resin (A) used in the present invention is not particularly limited, and various types can be used. Polycarbonate resins can be classified into aromatic polycarbonate resins in which the carbons directly bonded to carbonate bonds are aromatic carbons, and aliphatic polycarbonate resins in which the carbons directly bonded to carbonate bonds are aliphatic carbons, and either can be used. Among these, aromatic polycarbonate resins are preferred as the polycarbonate resin (A) from the viewpoints of heat resistance, mechanical properties, electrical properties, etc.

[0030] Among the monomers that serve as raw materials for aromatic polycarbonate resins, examples of aromatic dihydroxy compounds include: dihydroxybenzenes such as 1,2-dihydroxybenzene, 1,3-dihydroxybenzene (i.e., resorcinol), and 1,4-dihydroxybenzene; dihydroxybiphenyls such as 2,5-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, and 4,4'-dihydroxybiphenyl;

[0031] dihydroxynaphthalenes such as 2,2'-dihydroxy-1,1'-binaphthyl, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, and 2,7-dihydroxynaphthalene;

[0032] dihydroxydiaryl ethers such as 2,2'-dihydroxydiphenyl ether, 3,3'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 1,4-bis(3-hydroxyphenoxy)benzene, and 1,3-bis(4-hydroxyphenoxy)benzene;

[0033] 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C), 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(3-methoxy-4-hydroxyphenyl)propane, 1,1-bis(3-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(3-cyclohexyl-4-hydroxyphenyl)propane, α,α'-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, Bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)cyclohexylmethane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)(4-propenylphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)naphthylmethane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)-1-naphthyleethane, 1,1-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)hexane, 2,2-bis(4-hydroxyphenyl)hexane, 1,1-bis(4-hydroxyphenyl)octane, 2,2-bis(4-hydroxyphenyl)octane, bis(hydroxyaryl)alkanes such as 4,4-bis(4-hydroxyphenyl)heptane, 2,2-bis(4-hydroxyphenyl)nonane, 1,1-bis(4-hydroxyphenyl)decane, and 1,1-bis(4-hydroxyphenyl)dodecane;

[0034] 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,4-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,5-dimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxy-3,5-dimethylphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3-propyl-5-methylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3-tert-butyl-cyclohexane, 1,1-bis(4-hydroxyphenyl)-4-tert-butyl-cyclohexane, 1,1-bis(4-hydroxyphenyl)-3-phenylcyclohexane, bis(hydroxyaryl)cycloalkanes such as 1,1-bis(4-hydroxyphenyl)-4-phenylcyclohexane;

[0035] Cardo structure-containing bisphenols such as 9,9-bis(4-hydroxyphenyl)fluorene and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene;

[0036] Dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide; dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone; and the like.

[0037] Of these, bis(hydroxyaryl)alkanes are preferred, and bis(4-hydroxyphenyl)alkanes are particularly preferred, with 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A) and 2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C) being particularly preferred from the standpoints of impact resistance and heat resistance. The aromatic dihydroxy compounds may be used alone or in any combination and ratio of two or more.

[0038] Among the monomers serving as raw materials for polycarbonate resins, examples of carbonate precursors include carbonyl halides, carbonate esters, etc. The carbonate precursors may be used alone or in any combination and ratio of two or more.

[0039] Specific examples of carbonyl halides include phosgene; haloformates such as bischloroformates of dihydroxy compounds and monochloroformates of dihydroxy compounds; and the like.

[0040] Specific examples of carbonate esters include diaryl carbonates such as diphenyl carbonate and ditolyl carbonate; dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; biscarbonates of dihydroxy compounds, monocarbonates of dihydroxy compounds, and carbonates of dihydroxy compounds such as cyclic carbonates.

[0041] The method for producing the polycarbonate resin (A) is not particularly limited, and any method can be used. Examples include interfacial polymerization, melt transesterification, pyridine method, ring-opening polymerization of a cyclic carbonate compound, and solid-phase transesterification of a prepolymer. Among these, the interfacial polymerization and melt transesterification methods are preferred because they have a higher effect of improving moist heat resistance, and the interfacial polymerization method is particularly preferred.

[0042] The polycarbonate resin (A) used in the present invention may be a polycarbonate resin having a terminal structure represented by the following formula (1) as part or all thereof.

[0043] In the above formula (1), n ​​is an integer of 0 or 1, and R １ is an alkyl group having 4 to 14 carbon atoms. When the polycarbonate resin has the terminal structure of the above formula (1), it is possible to achieve high fluidity while maintaining strength, and high fluidity can be achieved even when a desired molecular weight is adopted without reducing the molecular weight of the polycarbonate resin, thereby enabling high impact resistance and high impact resistance at low temperatures.

[0044] R １ The number of carbon atoms in the alkyl group of R is preferably 4 or 6 or more, more preferably 12 or less, and even more preferably 10 or less. １ The alkyl group of R may be linear or branched. １ is preferably one or more selected from the group consisting of a t-butyl group, an n-octyl group, an iso-octyl group, and a t-octyl group, more preferably a t-butyl group or a t-octyl group, and the terminal structure in general formula (1) is preferably a t-octylphenyl group (i.e., a 1,1,3,3-tetramethylbutylphenyl group).

[0045] In the above formula (1), -(O) bonded to a phenyl group ｎ R １ The position of the group may be the ortho position, meta position or para position, but the para position shown in the following formula (1') is preferred.

[0046] R represented by the above formula (1) or (1′) １Specific examples of the group include alkylphenyl groups such as p-t-butyl group, p-pentylphenyl group, p-hexylphenyl group, p-heptylphenyl group, p-n-octylphenyl group, p-isooctylphenyl group, p-t-octylphenyl group, p-dodecylphenyl group, and p-tetradecylphenyl group, p-nonylphenol, p-dodecylphenol, amylphenol, hexylphenol, heptylphenol, octylphenol, nonylphenol, decylphenol, dodecylphenol, and myristylphenol, and alkoxyphenyl groups such as p-hexyloxyphenyl group, p-n-octyloxyphenyl group, p-isooctyloxyphenyl group, p-t-octyloxyphenyl group, and p-dodecyloxyphenyl group. １ Of these, the groups are preferably p-t-butyl, n-octyl, iso-octyl and t-octyl, more preferably p-t-butyl, p-n-octyl, p-iso-octyl and p-t-octyl, and particularly preferably p-t-octyl, since it can achieve high fluidity and therefore enables high impact resistance and low-temperature impact resistance.

[0047] When the polycarbonate resin having the terminal structure of the above formula (1) is contained, the proportion thereof is preferably 40% by mass or more, and even preferably 100% by mass, relative to 100% by mass of the entire polycarbonate resin (A).

[0048] The molecular weight of the polycarbonate resin (A), expressed as a viscosity average molecular weight (Mv) calculated from the solution viscosity measured at 25° C. using methylene chloride as a solvent, is preferably 10,000 to 50,000, more preferably 10,000 to 40,000, even more preferably 10,000 to 30,000 or 10,000 to 26,000, and even more preferably 10,500 or more, 11,000 or more, particularly preferably 11,500 or more, most preferably 12,000 or more, and still more preferably 24,000 or less, particularly preferably 20,000 or less. By setting the viscosity average molecular weight to be equal to or greater than the lower limit of the above range, the mechanical strength of the polycarbonate resin composition of the present invention can be further improved, while by setting the viscosity average molecular weight to be equal to or less than the upper limit of the above range, the decrease in flowability of the polycarbonate resin composition of the present invention can be suppressed and improved, and molding processability can be enhanced, allowing for easier molding processability. Two or more polycarbonate resins having different viscosity average molecular weights may be mixed together, and in this case, polycarbonate resins having viscosity average molecular weights outside the above-mentioned preferred range may be mixed.

[0049] The viscosity average molecular weight [Mv] is determined by measuring the intrinsic viscosity [η] (unit: dl / g) at 25°C using methylene chloride as a solvent with an Ubbelohde viscometer, and then calculating the viscosity average molecular weight [Mv] using the Schnell viscosity formula, i.e., η = 1.23 × 10 －４ Mv ０．８３ The intrinsic viscosity [η] is the specific viscosity [η] at each solution concentration [C] (g / dl). ｓｐ ] was measured and the value was calculated according to the following formula.

[0050] In order to improve the appearance and flowability of the molded article, the polycarbonate resin (A) may contain a polycarbonate oligomer. The viscosity average molecular weight [Mv] of this polycarbonate oligomer is usually 1,500 or more, preferably 2,000 or more, and usually 9,500 or less, preferably 9,000 or less. Furthermore, the amount of the polycarbonate oligomer contained is preferably 30% by mass or less of the polycarbonate resin (including the polycarbonate oligomer).

[0051] Furthermore, the polycarbonate resin (A) may be not only a virgin raw material but also a polycarbonate resin recycled from used products (so-called material-recycled polycarbonate resin), and it is also preferable to contain both a virgin raw material and a recycled resin, or it may be made of a recycled polycarbonate resin. When a recycled polycarbonate resin is used, the proportion of the recycled polycarbonate resin in the polycarbonate resin (A) is preferably 5% or more.

[0052] [Phosphorus-Based Stabilizer (C)] The polycarbonate resin composition of the present invention preferably contains a phosphorus-based stabilizer (C). The inclusion of a phosphorus-based stabilizer improves the color of the polycarbonate resin composition of the present invention and further improves its thermal discoloration resistance. Any known phosphorus-based stabilizer can be used. Specific examples include phosphorus oxoacids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; metal acid pyrophosphates such as sodium acid pyrophosphate, potassium acid pyrophosphate, and calcium acid pyrophosphate; phosphates of Group 1 or Group 2B metals such as potassium phosphate, sodium phosphate, cesium phosphate, and zinc phosphate; phosphate compounds, phosphite compounds, and phosphonite compounds, with compounds having a phosphite structure being particularly preferred. By selecting a phosphite compound, a polycarbonate resin composition having higher discoloration resistance and continuous productivity can be obtained.

[0053] The phosphite compound has the general formula: P(OR) ３where R represents a monovalent or divalent organic group. Examples of such phosphite compounds include triphenyl phosphite, tris(mononylphenyl)phosphite, tris(mononyl / dinonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, monooctyldiphenyl phosphite, dioctylmonophenyl phosphite, monodecyldiphenyl phosphite, didecylmonophenyl phosphite, tridecyl phosphite, trilauryl phosphite, tristearyl phosphite, distearyl pentaerythritol diphosphite, bis(2,4- di-tert-butyl-4-methylphenyl)pentaerythritol phosphite, bis(2,6-di-tert-butylphenyl)octyl phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene-diphosphite, 6-[3-(3-tert-butyl-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]-dioxaphosphepine, and the like.

[0054] Among these phosphite compounds, aromatic phosphite compounds represented by the following formula (1) or (2) are more preferred because they effectively enhance the heat discoloration resistance of the polycarbonate resin composition of the present invention.

[0055] [In formula (1), R １ , R ２ and R ３ may be the same or different and represent an aryl group having 6 to 30 carbon atoms.

[0056] [In formula (2), R ４ and R ５ may be the same or different and represent an aryl group having 6 to 30 carbon atoms.

[0057] Among the phosphite compounds represented by the above formula (1), triphenyl phosphite, tris(mononylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, etc. are preferred, and among these, tris(2,4-di-tert-butylphenyl)phosphite is more preferred. Specific examples of such organic phosphite compounds include "ADEKA STAB 1178" manufactured by ADEKA Corporation, "SUMIRAIZER TNP" manufactured by Sumitomo Chemical Co., Ltd., "JP-351" manufactured by Johoku Chemical Industry Co., Ltd., "ADEKA STAB 2112" manufactured by ADEKA Corporation, "IRGAFOS 168" manufactured by BASF, and "JP-650" manufactured by Johoku Chemical Industry Co., Ltd.

[0058] As the phosphite compound represented by the above formula (2), those having a pentaerythritol diphosphite structure, such as bis(2,4-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, and bis(2,4-dicumylphenyl)pentaerythritol diphosphite, are particularly preferred. Specific examples of such organic phosphite compounds include "ADK STAB PEP-36" and "ADK STAB PEP-24G" manufactured by ADEKA Corporation, and "Doverphos S-9228" manufactured by Doverchemical Corporation.

[0059] Among the phosphite compounds, the aromatic phosphite compounds represented by the above formula (2) are more preferred because they have a more excellent hue. The phosphorus-based stabilizer may be contained alone or in any combination and ratio of two or more kinds.

[0060] The content of the phosphorus-based stabilizer (C) is preferably 0.005 to 0.5 parts by mass, more preferably 0.007 parts by mass or more, even more preferably 0.008 parts by mass or more, particularly preferably 0.01 parts by mass or more, and more preferably 0.4 parts by mass or less, even more preferably 0.3 parts by mass or less, among which preferably 0.2 parts by mass or less, and particularly preferably 0.1 parts by mass or less, relative to 100 parts by mass of the polycarbonate resin (A). If the content of the phosphorus-based stabilizer (C) is less than 0.005 parts by mass within the above range, the hue and heat discoloration resistance tend to be insufficient, whereas if the content of the phosphorus-based stabilizer (C) exceeds 0.5 parts by mass, the heat discoloration resistance tends to deteriorate and the moist heat stability also tends to decrease.

[0061] [Epoxy Compound and / or Oxetane Compound (D)] The resin composition of the present invention also preferably contains an epoxy compound and / or an oxetane compound (D). By containing the epoxy compound and / or the oxetane compound (D), heat discoloration resistance can be further improved. The content of the epoxy compound and / or the oxetane compound (D) is preferably 0.0005 to 0.2 parts by mass per 100 parts by mass of the polycarbonate resin (A).

[0062] The epoxy compound used is a compound having one or more epoxy groups in one molecule. Specific examples include phenyl glycidyl ether, allyl glycidyl ether, t-butylphenyl glycidyl ether, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-6'-methylcyclohexylcarboxylate, 2,3-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate, 4-(3,4-epoxy-5-methylcyclohexyl)butyl-3',4'-epoxy, and the like. bisphenol-A diglycidyl ether, tetrabromobisphenol-A glycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, bis-epoxy dicyclopentadienyl ether, bis-epoxy ethylene oxide, cyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6'-methylcyclohexylcarboxylate, bisphenol-A diglycidyl ether, tetrabromobisphenol-A glycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, bis-epoxy dicyclopentadienyl ether, bis-epoxy ethylene oxide ... ethylene glycol, bis-epoxycyclohexyl adipate, butadiene diepoxide, tetraphenylethylene epoxide, octyl epoxy thalate, epoxidized polybutadiene, 3,4-dimethyl-1,2-epoxycyclohexane, 3,5-dimethyl-1,2-epoxycyclohexane, 3-methyl-5-t-butyl-1,2-epoxycyclohexane, octadecyl-2,2-dimethyl-3,4-epoxycyclohexylcarboxylate, N-butyl-2,2-dimethyl-3,4-epoxycyclohexylcarboxylate carboxylate, cyclohexyl-2-methyl-3,4-epoxycyclohexylcarboxylate, N-butyl-2-isopropyl-3,4-epoxy-5-methylcyclohexylcarboxylate, octadecyl-3,4-epoxycyclohexylcarboxylate, 2-ethylhexyl-3',4'-epoxycyclohexylcarboxylate, 4,6-dimethyl-2,3-epoxycyclohexyl-3',4'-epoxycyclohexylcarboxylate, 4,5-epoxytetrahydrophthalic anhydride, 3-t-butyl-4,Preferred examples include 5-epoxytetrahydrophthalic anhydride, diethyl 4,5-epoxy-cis-1,2-cyclohexyldicarboxylate, di-n-butyl-3-t-butyl-4,5-epoxy-cis-1,2-cyclohexyldicarboxylate, epoxidized soybean oil, and epoxidized linseed oil.

[0063] Of these, alicyclic epoxy compounds are preferably used, and 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate is particularly preferred.

[0064] Also, polyalkylene glycol derivatives having epoxy groups at one or both ends can be preferably used, and polyalkylene glycols having epoxy groups at both ends are particularly preferred.

[0065] Preferred examples of the polyalkylene glycol derivative containing an epoxy group in its structure include polyethylene glycol diglycidyl ether, poly(1-methyl)ethylene glycol diglycidyl ether, poly(2-ethyl)ethylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, polyethylene glycol-poly(1-methyl)ethylene glycol diglycidyl ether, polytetramethylene glycol-poly(2-methyl)ethylene glycol diglycidyl ether, and polytetramethylene glycol-poly(1-ethyl)ethylene glycol diglycidyl ether.

[0066] The epoxy compounds may be used alone or in combination of two or more.

[0067] The content of the epoxy compound is preferably 0.0005 to 0.2 parts by mass relative to 100 parts by mass of the polycarbonate resin (A), more preferably 0.001 part by mass or more, even more preferably 0.003 part by mass or more, particularly preferably 0.005 part by mass or more, and more preferably 0.15 part by mass or less, even more preferably 0.1 part by mass or less, particularly preferably 0.05 part by mass or less. If the content of the epoxy compound is less than 0.0005 part by mass, the hue and heat discoloration resistance tend to be insufficient, while if it exceeds 0.2 part by mass, the heat discoloration resistance tends to deteriorate and the hue and moist heat stability tend to decrease.

[0068] The oxetane compound can be any compound having one or more oxetane groups in the molecule, including monooxetane compounds having one oxetane group in the molecule and polyoxetane compounds having two or more oxetane groups in the molecule, which are bifunctional or higher functional. The inclusion of an oxetane compound can further improve the excellent hue and high thermal discoloration resistance.

[0069] Preferred examples of the monooxetane compound include compounds represented by the following general formula (3), (4) or (5).

[0070] [In the above formulas (3) to (5), R １ is an alkyl group, R ２ represents an alkyl group or a phenyl group, and R ３ represents a divalent organic group which may have an aromatic ring, and n represents 0 or 1.

[0071] In the above general formulas (3), (4) and (5), R １ is an alkyl group, preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and most preferably an ethyl group. ２is an alkyl group or a phenyl group, preferably an alkyl group having 2 to 10 carbon atoms, and may be any of a linear alkyl group, a branched alkyl group, and an alicyclic alkyl group, or may be a linear or branched alkyl group having an ether bond (an ether-type oxygen atom) in the middle of the alkyl chain. ２ Specific examples of R include an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, a 3-oxypentyl group, a cyclohexyl group, and a phenyl group. ２ is preferably a 2-ethylhexyl group, a phenyl group, or a cyclohexyl group.

[0072] Preferred specific examples of the compound of general formula (3) include 3-hydroxymethyl-3-methyloxetane, 3-hydroxymethyl-3-ethyloxetane, 3-hydroxymethyl-3-propyloxetane, 3-hydroxymethyl-3-n-butyloxetane, and 3-hydroxymethyl-3-propyloxetane. Of these, 3-hydroxymethyl-3-methyloxetane and 3-hydroxymethyl-3-ethyloxetane are particularly preferred. Preferred specific examples of the compound of general formula (4) include 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane.

[0073] In the above general formula (5), R ３ is a divalent organic group which may have an aromatic ring, examples of which include linear or branched alkylene groups having 1 to 12 carbon atoms, such as an ethylene group, a propylene group, a butylene group, a neopentylene group, an n-pentamethylene group, and an n-hexamethylene group; a phenylene group; ２ -Ph-CH ２ - or -CH ２ -Ph-Ph-CH ２ Examples of the divalent group include a divalent group represented by - (where Ph represents a phenyl group), a hydrogenated bisphenol A residue, a hydrogenated bisphenol F residue, a hydrogenated bisphenol Z residue, a cyclohexanedimethanol residue, and a tricyclodecanedimethanol residue.

[0074] Particularly preferred examples of the compound of general formula (5) include bis(3-methyl-3-oxetanylmethyl)ether, bis(3-ethyl-3-oxetanylmethyl)ether, bis(3-propyl-3-oxetanylmethyl)ether, bis(3-butyl-3-oxetanylmethyl)ether, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane, 4,4′-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, and 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]benzene.

[0075] The oxetane compounds may be used alone or in combination of two or more.

[0076] When an oxetane compound is contained, the content thereof is preferably 0.0005 to 0.2 parts by mass, more preferably 0.001 part by mass or more, even more preferably 0.003 part by mass or more, particularly preferably 0.005 part by mass or more, and more preferably 0.15 part by mass or less, even more preferably 0.1 part by mass or less, particularly preferably 0.05 part by mass or less, relative to 100 parts by mass of the polycarbonate resin (A). If the content of the oxetane compound is less than 0.0005 part by mass, the hue and heat discoloration resistance tend to be insufficient, whereas if it exceeds 0.2 part by mass, the heat discoloration resistance tends to deteriorate and gas is likely to be generated during molding.

[0077] It is also preferable to contain both the epoxy compound and the oxetane compound together, and when both are contained, the total content is preferably 0.0005 to 0.2 parts by mass per 100 parts by mass of the polycarbonate resin (A).

[0078] [Fatty Acid Ester (E)] The resin composition of the present invention preferably contains a fatty acid ester (E). The fatty acid ester (E) is preferably an ester of an aliphatic carboxylic acid and an alcohol, since the resin composition has a good hue.

[0079] Examples of the aliphatic carboxylic acid in the ester of an aliphatic carboxylic acid and an alcohol include saturated or unsaturated aliphatic mono-, di-, or tri-carboxylic acids. Here, aliphatic carboxylic acids also include alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are mono- or di-carboxylic acids having 6 to 36 carbon atoms, with saturated aliphatic mono-carboxylic acids having 6 to 36 carbon atoms being more preferred. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetraliacontanoic acid, montanic acid, adipic acid, and azelaic acid.

[0080] Examples of alcohols in the esters of aliphatic carboxylic acids and alcohols include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, monohydric or polyhydric saturated alcohols having 30 or fewer carbon atoms are preferred, and aliphatic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols having 30 or fewer carbon atoms are more preferred. Note that the term "aliphatic" is used here to encompass alicyclic compounds. Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, and dipentaerythritol.

[0081] The ester may contain an aliphatic carboxylic acid and / or alcohol as an impurity. The ester may be a pure substance or a mixture of multiple compounds. The aliphatic carboxylic acid and alcohol that combine to form an ester may each be used alone or in any combination and ratio of two or more.

[0082] Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture containing myricyl palmitate as a main component), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, and pentaerythritol tetrastearate.

[0083] The content of the fatty acid ester (E) is preferably 0.01 to 0.5 parts by mass based on 100 parts by mass of the polycarbonate resin (A).

[0084] [Additives, etc.] The polycarbonate resin composition of the present invention may contain additives other than those described above, such as antioxidants, ultraviolet absorbers, fluorescent whitening agents, pigments, dyes, polymers other than polycarbonate resins, flame retardants, impact modifiers, antistatic agents, plasticizers, compatibilizers, etc. One or more of these additives may be blended. However, when a polymer other than the polycarbonate resin (A) is contained, the content thereof is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less, per 100 parts by mass of the polycarbonate resin (A).

[0085] [Method for Producing Polycarbonate Resin Composition] There are no limitations on the method for producing the polycarbonate resin composition of the present invention, and a wide variety of known methods for producing polycarbonate resin compositions can be employed, including a method in which the above-mentioned essential components and other components that are added as needed are premixed using various mixers such as a tumbler or a Henschel mixer, and then melt-kneaded using a mixer such as a Banbury mixer, a roll, a Brabender, a single-screw kneading extruder, a twin-screw kneading extruder, a kneader, etc. The melt-kneading temperature is not particularly limited, but is usually in the range of 240 to 320°C.

[0086] [Polycarbonate Resin Composition] The polycarbonate resin composition of the present invention has excellent hue and therefore excellent YI (yellowing index), and the initial YI value at an optical path length of 300 mm is preferably 23 or less, more preferably 22 or less, 21.5 or less, 21 or less, and even more preferably 20.5 or less. The initial YI value is measured by molding a long optical path molded product (300 mm × 7 mm × 4 mm) at a resin temperature of 340°C and a mold temperature of 80°C, and measuring the YI value (initial YI value) at an optical path length of 300 mm, using a C light source, and a 2° field of view.

[0087] [Optical Parts] The polycarbonate resin composition of the present invention can be pelletized and molded by various molding methods to produce optical parts. Alternatively, the resin can be melt-kneaded in an extruder and directly molded into optical parts without going through pelletization.

[0088] The polycarbonate resin composition of the present invention has excellent fluidity and color, and generates very little gas during molding and causes little mold contamination. Therefore, it is particularly suitable for use in injection molding optical components, particularly thin-walled optical components, which are prone to mold contamination. The resin temperature during injection molding is preferably higher than the 260-300°C temperature generally used in injection molding of polycarbonate resins, with a resin temperature of 305-400°C being preferred, particularly in the case of thin-walled molded articles. The resin temperature is more preferably 310°C or higher, even more preferably 315°C or higher, particularly preferably 320°C or higher, and more preferably 390°C or lower. When conventional polycarbonate resin compositions are used, increasing the resin temperature during molding to form thin-walled molded articles can lead to the problem of yellowing of the molded articles. However, by using the resin composition of the present invention, it is possible to produce molded articles, particularly thin-walled optical components, with good color and high transparency, even within the above temperature range. Note that when direct measurement is difficult, the resin temperature is understood to be the barrel set temperature.

[0089] Here, the thin-walled molded article refers to a molded article having a plate-like portion with a thickness of usually 1 mm or less, preferably 0.8 mm or less, more preferably 0.6 mm or less. Here, the plate-like portion may be flat or curved, may have a flat surface or may have an uneven surface, and may have an inclined cross section or a wedge-shaped cross section.

[0090] The optical component may be in the form of a film or sheet, and a specific example thereof is a light guide film.

[0091] Furthermore, suitable optical components include light guides and lenses that guide light from a light source such as an LED in vehicle headlamps, rear lamps, fog lamps, etc. for automobiles or motorcycles, and the present invention can also be suitably used for these.

[0092] Optical components include components of devices and appliances that directly or indirectly utilize light sources such as LEDs, organic electroluminescent (EL) lamps, incandescent lamps, fluorescent lamps, and cathode tubes. Representative examples include light guide plates and surface light emitters. Light guide plates are used in liquid crystal backlight units and various display devices and lighting devices to guide light from light sources such as LEDs. Light entering from the side or back side is usually diffused by irregularities on the surface, resulting in uniform light. The shape of the light guide plate is usually flat, and the surface may or may not have irregularities. Light guide plates are typically molded by injection molding, ultra-high speed injection molding, injection compression molding, melt extrusion molding (e.g., T-die molding), or the like. Light guide plates molded using the resin composition of the present invention exhibit good hue and high transparency without cloudiness or reduced transmittance, and exhibit few molding defects due to mold contamination.

[0093] The light guide plate using the polycarbonate resin composition of the present invention can be suitably used in the fields of liquid crystal backlight units, various display devices, and lighting devices. Examples of such devices include various mobile terminals such as mobile phones, mobile notebooks, netbooks, slate PCs, tablet PCs, smartphones, and tablet terminals, as well as cameras, watches, notebook computers, various displays, and lighting equipment. Among these, the light guide plate can be particularly suitably used as a high-performance edge-lit light guide plate.

[0094] The present invention will be described in more detail below with reference to examples. However, the present invention should not be construed as being limited to the following examples. The raw materials used in the following examples and comparative examples are as shown in Table 1.

[0095]

[0096] (Examples 1 to 15, Comparative Examples 1 to 7) [Production of Resin Composition Pellets] The above-described components were blended in the proportions (parts by mass) shown in Tables 2 and 3 below, and mixed in a tumbler for 20 minutes. The mixture was then melt-kneaded at a cylinder temperature of 240°C using a vented single-screw extruder with a screw diameter of 40 mm ("VS-40" manufactured by Tanabe Plastic Machinery Co., Ltd.), and pellets were obtained by strand cutting.

[0097] [Transparency of Strands During Production of Resin Composition Pellets] In the above-described production process for resin composition pellets, the transparency of strands melt-kneaded and extruded by an extruder was visually evaluated according to the following criteria. A: The extruded strands had extremely high transparency, and the compatibility between the polycarbonate resin (A) and the polylactone-polyether copolymer (B) was extremely good. B: The extruded strands had high transparency, and the compatibility between the polycarbonate resin (A) and the polylactone-polyether copolymer (B) was good. C: The extruded strands were slightly cloudy, and the compatibility between the polycarbonate resin (A) and the polylactone-polyether copolymer (B) was poor. D: The extruded strands were strongly cloudy, and the compatibility between the polycarbonate resin (A) and the polylactone-polyether copolymer (B) was extremely poor.

[0098] [Gas Generation During Molding (Evaluation of Mold Contamination)] Evaluation of Contamination During Injection Molding (Mold Contamination) The pellets obtained above were dried at 120°C for 5 hours, and then injection-molded for 200 shots using an injection molding machine (SE7M manufactured by Sumitomo Heavy Industries, Ltd.) with a teardrop-shaped mold as shown in Figure 1 under conditions of a cylinder temperature of 340°C, a molding cycle of 10 seconds, and a mold temperature of 40°C. After completion of the molding, the state of contamination due to white deposits that had occurred on the metal mirror surface on the mold fixing side was evaluated visually according to the following criteria: A: Mold deposits were extremely small, and mold contamination resistance was extremely good. B: Mold deposits were small, but some mold contamination resistance was observed. C: Mold deposits were somewhat large, and mold contamination was observed. D: Mold deposits were large, and mold contamination was observed significantly.

[0099] The teardrop-shaped mold in Fig. 1 is designed so that the resin composition is introduced through gate G and the generated gas is easily accumulated at tip P. Gate G has a width of 1 mm and a thickness of 1 mm, and in Fig. 1, width h1 is 14.5 mm, length h2 is 7 mm, length h3 is 27 mm, and the thickness of the molded portion is 3 mm.

[0100] [Color (YI)] The obtained pellets were dried at 120°C for 5 to 7 hours in a hot air circulation dryer, and then molded into long-optical path molded articles (300 mm x 7 mm x 4 mm) using an injection molding machine ("HSP100A" manufactured by Sodick) at a resin temperature of 340°C and a mold temperature of 80°C. The YI (yellowing index) of these long-optical path molded articles was measured at an optical path length of 300 mm. A long-optical path spectrophotometer ("ASA 1" manufactured by Nippon Denshoku Industries Co., Ltd., C light source, 2° field of view) was used for the measurement.

[0101] The above evaluation results are shown in Table 2-3 below.

[0102]

[0103]

[0104] The polycarbonate resin composition of the present invention has a good hue, excellent transparency, extremely little gas generation and mold contamination during molding, and excellent impact resistance, and therefore can be extremely suitably used for various molded products, particularly optical parts.

Claims

1. A polycarbonate resin composition comprising 0.01 to 4 parts by mass of a polylactone-polyether copolymer (B) per 100 parts by mass of a polycarbonate resin (A).

2. The polycarbonate resin composition according to claim 1, wherein the molar ratio of polylactone units to polyether units in the polylactone-polyether copolymer (B) is 5:95 to 95:

5.

3. The polycarbonate resin composition according to claim 1 or 2, wherein the polylactone-polyether copolymer (B) is a polycaprolactone-polyether copolymer.

4. The polycarbonate resin composition according to claim 3, wherein the polycaprolactone-polyether copolymer (B) is a polycaprolactone-polyether copolymer represented by the following general formula (I) or (II): (In formulas (I) and (II), R1 to R4 each represent a linear or branched hydrocarbon group having 2 to 20 carbon atoms which may be substituted with an aryloxy group or an alkoxy group, and R5 represents CH ２ CHCH ２ , C.H. ３ C (CH ２ ) ３ , or C.H. ３ CH ２ C (CH ２ ) ３ a is an integer of 3 or more, b and c are each an integer of 1 or more, l, m, and n are each an integer of 1 or more, and o, p, and q are each an integer of 1 or more.

5. The polycarbonate resin composition according to claim 4, wherein R1 to R4 in said general formulas (I) and (II) are alkylene groups selected from the group consisting of 1,2-ethylene groups, 1,2-propylene groups, trimethylene groups, 1,2-butylene groups and tetramethylene groups.

6. The polycarbonate resin composition according to claim 1 or 2, wherein the polylactone-polyether copolymer (B) has a number average molecular weight (Mn) of 200 to 10,000.

7. The polycarbonate resin composition according to claim 1 or 2, wherein the viscosity average molecular weight (Mv) of the polycarbonate resin (A) is 10,000 to 50,000.

8. The polycarbonate resin composition according to claim 1 or 2, further comprising 0.005 to 0.5 parts by mass of a phosphorus-based stabilizer (C) per 100 parts by mass of the polycarbonate resin (A).

9. The polycarbonate resin composition according to claim 8, wherein the phosphorus-based stabilizer (C) is a phosphorus-based compound having a phosphite structure.

10. The polycarbonate resin composition according to claim 9, wherein the phosphorus-based stabilizer (C) contains two or more phosphorus-based compounds having a phosphite structure, at least one of which is a phosphite-based stabilizer having a spiro ring skeleton.

11. The polycarbonate resin composition according to claim 1 or 2, further comprising an epoxy compound and / or an oxetane compound (D) in an amount of 0.0005 to 0.2 part by mass per 100 parts by mass of the polycarbonate resin (A).

12. The polycarbonate resin composition according to claim 1 or 2, further comprising 0.01 to 0.5 parts by mass of a fatty acid ester (E) per 100 parts by mass of the polycarbonate resin (A).

13. Pellets comprising the polycarbonate resin composition according to claim 1 or 2.

14. A molded article obtained by molding the pellets according to claim 13.

15. The molded article according to claim 14, which is an optical part.

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