Light guide member

Abstract

A light guide component with extremely excellent hue and transparency. [Solution] A light guide member molded from a polycarbonate resin composition containing 0.01 to 4 parts by mass of polylactone-polyether copolymer (B) per 100 parts by mass of polycarbonate resin (A), characterized in that the molar ratio of lactone units to ether units of the polylactone-polyether copolymer (B) is 30 to 95:70 to 5.

Description

[Technical Field]

[0001] The present invention relates to a light guide member, and more particularly to a light guide member having extremely excellent hue and transparency. [Background technology]

[0002] Liquid crystal display devices used in personal computers, mobile phones, and other devices incorporate planar light sources to meet the demands for thinner, lighter, more efficient, and higher-resolution displays. These planar light sources are equipped with wedge-shaped or flat light guide plates, which have one uniformly inclined surface, to uniformly and efficiently guide incoming light to the liquid crystal display. Some also have a light scattering function provided by forming an uneven pattern on the surface of the light guide plate.

[0003] Such light guide plates are obtained by injection molding of thermoplastic resin, and the above-mentioned uneven pattern is imparted by transferring the uneven surface formed on the surface of an insert 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 project clearer images, and the temperature inside the device tends to rise due to the heat generated near the light source. Therefore, they are being replaced with polycarbonate resin materials, which have higher heat resistance.

[0004] However, while polycarbonate resin excels in mechanical, thermal, electrical properties, weather resistance, light transmittance, and transparency, there is a growing demand to minimize the chromaticity difference between the light-receiving and distant areas of a light guide plate. Polycarbonate resin has the problem of being more prone to yellowing compared to PMMA.

[0005] Patent Document 1 proposes incorporating polyalkylene glycol, composed of linear alkyl groups, into polycarbonate resin to improve transmittance and hue. Improvements in transmittance and yellowing (yellow index: YI) can be observed by incorporating polytetramethylene ether glycol.

[0006] In particular, in recent years, light guide components such as light guide plates in mobile devices such as smartphones and tablet terminals have been becoming thinner and larger at a remarkable pace, requiring high barrel temperatures and high-speed injection molding for the molding of light guide plates. Consequently, the amount of gas generated during molding increases, leading to problems such as mold contamination. Therefore, the resin compositions used for these moldings are required to have not only excellent color (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 edge-lit light guide plates, monitors are becoming larger, thinner, and more high-performance, requiring further improvements in the transparency, hue, and mold contamination resistance of the light guide components. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 5699188 [Overview of the project] [Problems that the invention aims to solve]

[0008] This invention has been made in view of the above circumstances, and its purpose is to provide a light guide member that has an extremely excellent hue and high transparency. [Means for solving the problem]

[0009] The inventors, after diligent research to achieve the above objectives, discovered that a light guide member molded from a polycarbonate resin composition containing a specific amount of a polylactone-polyether copolymer in which the molar ratio of lactone units to ether units is within a specific range can solve the aforementioned problems, and thus completed the present invention. The present invention relates to the following light guide member.

[0010] 1. A light guide member formed from a polycarbonate resin composition containing 0.01 to 4 parts by mass of a poly(lactone - polyether) copolymer (B) with respect to 100 parts by mass of a polycarbonate resin (A), wherein the molar ratio of the lactone unit to the ether unit of the poly(lactone - polyether) copolymer (B) is 30 to 95:70 to 5. 2. The light guide member according to 1 above, wherein the poly(lactone - polyether) copolymer (B) is a poly(caprolactone - polyether) copolymer.

[0011] 3. The light guide member according to 2 above, wherein the poly(caprolactone - polyether) copolymer (B) is a poly(caprolactone - polyether) copolymer represented by the following general formula (I) or (II).

[0012] [Chemical formula] [Chemical formula] [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 allyloxy group or an alkoxy group, and R5 is CH2CHCH2, CH3C(CH2)3, or CH3CH2C(CH2)3. a is an integer of 3 or more, b and c are each an integer of 1 or more, and l, m, n, o, p, and q are each an integer of 1 or more.] 4. The light guide member according to 3 above, wherein R1 to R4 in the general formulas (I) and (II) are alkylene groups selected from the group consisting of 1,2 - ethylene group, 1,2 - propylene group, trimethylene group, 1,2 - butylene group, and tetramethylene group.

[0013] 5. The light guide member according to any one of 1 to 4 above, wherein the number average molecular weight (Mn) of the poly(lactone - polyether) copolymer (B) is 200 to 10,000. 6. The light guide member according to any one of 1 to 5 above, wherein the viscosity average molecular weight (Mv) of the polycarbonate resin (A) is 10,000 to 50,000. 7. The light guide member according to any one of claims 1 to 6 above, wherein the polycarbonate resin composition further contains a phosphorus-based stabilizer (C) in an amount of 0.005 to 0.5 parts by mass per 100 parts by mass of the polycarbonate resin (A). 8. The light guide member according to item 7 above, wherein the phosphorus-based stabilizer (C) is a phosphorus-based compound having a phosphite structure. 9. The light guide member according to 7 or 8 above, wherein the phosphorus-based stabilizer (C) contains two or more phosphorus-based compounds having a phosphite structure, and one or more of these compounds are phosphite compounds having a spiro-ring skeleton. 10. The light guide member according to any one of claims 1 to 9 above, wherein the polycarbonate resin composition further contains an epoxy compound and / or an oxetane compound (D) in an amount of 0.0005 to 0.2 parts by mass per 100 parts by mass of polycarbonate resin (A). 11. The light guide member according to any one of claims 1 to 10, wherein the polycarbonate resin composition further contains 0.005 to 0.5 parts by mass of fatty acid ester (E) per 100 parts by mass of polycarbonate resin (A). 12. A pellet made from a polycarbonate resin composition containing 0.01 to 4 parts by mass of polylactone-polyether copolymer (B) per 100 parts by mass of polycarbonate resin (A), characterized in that the molar ratio of lactone units to ether units of the polylactone-polyether copolymer (B) is 30 to 95:70 to 5. [Effects of the Invention]

[0014] The light guide member of the present invention has a low YI value, extremely good hue, and transparency. [Modes for carrying out the invention]

[0015] The present invention will be described in detail below with reference to embodiments and examples. In this specification, unless otherwise specified, "~" means that the numbers before and after it are included as the lower and upper limits.

[0016] The light guide member of the present invention is a light guide member molded from a polycarbonate resin composition containing 0.01 to 4 parts by mass of polylactone-polyether copolymer (B) per 100 parts by mass of polycarbonate resin (A), characterized in that the molar ratio of lactone units to ether units of the polylactone-polyether copolymer (B) is 30 to 95:70 to 5.

[0017] [Polylactone-polyether copolymer (B)] The polycarbonate resin composition used in the present invention contains a polylactone-polyether copolymer (B) having a molar ratio of lactone units to ether units of 30-95:70-5. The polylactone-polyether copolymer (B) is a copolymer composed of units derived from a lactone compound and ether units derived from ether or polyglycol. It may be a random copolymer or a block copolymer, but a block copolymer consisting of polylactone blocks and polyether blocks is preferred, and a block copolymer in which polylactone is linked to the ends of the polyether is preferred.

[0018] By including a polylactone-polyether copolymer (B) with a molar ratio of lactone units to ether units of 30-95:70-5, a light guide member can be made with a low YI value, extremely good hue, and high transparency. The molar ratio of lactone units to ether units is preferably 35-90:65-10, more preferably 40-85:60-15, even more preferably 50-75:50-25, and particularly preferably 60-65:40-35. Furthermore, the molar ratio of each unit in the polylactone-polyether copolymer (B) was measured as follows: 1 The measurement is performed using a 1H-NMR spectrometer with 1,1,2,2-tetrachloroethane-d2 as the 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. Among the lactone compounds, ε-caprolactone is particularly preferred.

[0020] The etheric unit is -[R 1 If we denote it as -O]-, then R 1 R is a linear or branched hydrocarbon group with 2 to 20 carbon atoms. 1 The group may be substituted with an aliloxy group or an alkoxy group, for example, a group having an aromatic ring such as a 1-phenoxymethyl group.

[0021] R 1 The carbon group is preferably a hydrocarbon group having 2 to 6 carbon atoms, and more particularly an alkylene group. Examples of linear hydrocarbon groups having 2 to 6 carbon atoms include the 1,2-ethylene group, trimethylene group, tetramethylene group, pentamethylene group, and hexamethylene group. Examples of branched hydrocarbon groups having 2 to 6 carbon atoms include 1,2-propylene group, 1,2-butylene group, 2-methyl(1,2-propylene group), 2,2-dimethyl(1,2-propylene group), 1,2-dimethyl(1,2-propylene group), 1-methyl(1,2-propylene group), 1,2,2-trimethyl(1,2-propylene group), 2-methyl(1,2-butylene group), 1-methyl(1,2-butylene group), 1-isopropylene(1,2-ethylene group), 2-methyl,1-isopropylene(1,2-ethylene group), 1-tert-butyl(1,2-ethylene group), 2-ethyl(1,2-butylene group), 1-ethyl(1,2-butylene group), 1,1-dimethyltrimethylene group, 2-methyltetramethylene group, and 1-methylpentylene group. R 1 Among these, 1,2-ethylene groups, 1,2-propylene groups, trimethylene groups, 1,2-butylene groups, and tetramethylene groups are preferred, with 1,2-propylene groups, trimethylene groups, and tetramethylene groups being particularly preferred. R 1These 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 can be produced by known methods. For example, a method of ring-opening polymerization of a lactone compound followed by esterification copolymerization (block copolymerization) with a polyether glycol or alkylene oxide having the ether units described above is preferred.

[0023] During copolymerization, diol compounds, triol compounds, etc., may be present. Examples of diol compounds 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 triol compounds include glycerin, trimethylolethane, trimethylolpropane, butanetriol, pentanetriol, hexanetriol, heptanetriol, and octantriol, among which glycerin and trimethylolpropane are preferred. When a triol compound is used, the polylactone-polyether copolymer (B) becomes a three-branched polymer.

[0024] The polycaprolactone-polyether copolymer (B) is preferably one represented by the following general formula (I) or (II). [ka] [ka] [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 allyloxy group (also called an allyloxy group) or an alkoxy group, and R5 is CH2CHCH2, CH3C(CH2)3, or CH3CH2C(CH2)3. a is an integer of 3 or more, b and c are integers of 1 or more, and l, m, n, o, p, and q are integers of 1 or more.]

[0025] In general formulas (I) and (II), l, m, and n are each integers of 1 or more, preferably between 1 and 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. Furthermore, o, p, and q are each integers of 1 or more, preferably between 1 and 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. a is an integer of 3 or more, preferably between 3 and 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. b and c are each integers of 1 or more, preferably between 1 and 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.

[0026] As described above, R1 to R4 are linear or branched hydrocarbon groups having 2 to 20 carbon atoms, and may be substituted with an allyloxy group or an alkoxy group. For example, those having an aromatic ring such as a 1-phenoxymethyl group may also be used. R1 to R4 are preferably the same as R in [R 1 -O] in the above-described ether unit. 1 R1 to R4 are preferably an alkylene group 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. Also, R5 is CH2CHCH2, CH3C(CH2)3, or CH3CH2C(CH2)3, and CH2CHCH2 is particularly preferable. When l, m, and n are 2 or more, R1 to R4 may be the same hydrocarbon group or different hydrocarbon groups.

[0027] The number average molecular weight (Mn) of the poly(lactone)-polyether copolymer (B) is preferably from 200 to 10,000, more preferably 300 or more, still more preferably 500 or more, and 5,000 or less is more preferable, still more preferably 4,500 or less. When the number average molecular weight is within such a range, the compatibility with the polycarbonate resin (A) is excellent, and it is less likely that gas will be generated during molding. When the number average molecular weight exceeds the above upper limit, the compatibility tends to decrease, and when the number average molecular weight is below the above lower limit, gas is likely to be generated during molding. The number average molecular weight (Mn) of the poly(lactone)-polyether copolymer (B) is the number average molecular weight (Mn) calculated based on the hydroxyl value measured in accordance with JIS K1557. <​The content of the polylactone-polyether copolymer (B) is 0.01 to 4 parts by mass per 100 parts by mass of the polycarbonate resin (A). By including it within this range, the polycarbonate resin composition has a good hue and superior transparency. The content is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and even more preferably 1.5 parts by mass or less. If the content of the polylactone-polyether copolymer (B) is below the lower limit or above the upper limit, the resulting molded article tends to have an inferior hue.

[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 carbon atoms directly bonded to the carbonate bonds are aromatic carbon atoms, and aliphatic polycarbonate resins, in which the carbon atoms are aliphatic carbon atoms, and either can be used. Among these, aromatic polycarbonate resin is preferred as the polycarbonate resin (A) from the viewpoint of heat resistance, mechanical properties, electrical properties, etc.

[0030] Examples of aromatic dihydroxy compounds among the monomers used as raw materials for aromatic polycarbonate resins 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] Dihydroxynaphthalene compounds 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-naphthylethane, 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, 4,4-bis(4-hydroxyphenyl)heptane, 2,2-bis(4-hydroxyphenyl)nonane, 1,1-bis(4-hydroxyphenyl)decane, 1,1-Bis(4-hydroxyphenyl)dodecane, Bis(hydroxyaryl)alkanes such as;

[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, 1,1-Bis(4-hydroxyphenyl)-4-phenylcyclohexane, Bis(hydroxyaryl)cycloalkanes such as;

[0035] 9,9-Bis(4-hydroxyphenyl)fluorene, Bisphenols containing cardo structures, such as 9,9-bis(4-hydroxy-3-methylphenyl)fluorene;

[0036] 4,4'-Dihydroxydiphenyl sulfide, Dihydroxydiaryl sulfides such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide; Dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; 4,4'-Dihydroxydiphenylsulfone, Dihydroxydiarylsulfones such as 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone; These are some examples.

[0037] Among these, bis(hydroxyaryl)alkanes are preferred, and among them, bis(4-hydroxyphenyl)alkanes are preferred, and in particular, 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A) and 2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C) are preferred from the viewpoint of impact resistance and heat resistance. Furthermore, one aromatic dihydroxy compound may be used, or two or more may be used in any combination and ratio.

[0038] Among the monomers used as raw materials for polycarbonate resin, examples of carbonate precursors include carbonyl halides and carbonate esters. Note that one type of carbonate precursor may be used, or two or more types may be used in any combination and ratio.

[0039] Examples of carbonyl halides include, specifically, phosgene; bischloroformates of dihydroxy compounds; monochloroformates of dihydroxy compounds; and other haloformates.

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

[0041] The method for producing the polycarbonate resin (A) is not particularly limited, and any method can be used. Examples include interfacial polymerization, molten transesterification, pyridine method, ring-opening polymerization of cyclic carbonate compounds, and solid-phase transesterification of prepolymers. Among these, interfacial polymerization and molten transesterification are preferred because they offer a greater improvement in moisture and heat resistance, with interfacial polymerization being particularly preferred.

[0042] In the present invention, the polycarbonate resin (A) used may be a polycarbonate resin having an end structure represented by the following formula (1), either partially or entirely. [ka]

[0043] In equation (1) above, n is an integer of 0 or 1, and R 1 This is an alkyl group having 4 to 14 carbon atoms. By having the terminal structure of formula (1) above, the polycarbonate resin can achieve high fluidity while maintaining strength, and high fluidity can be achieved even when adopting the desired molecular weight without lowering the molecular weight of the polycarbonate resin, thus enabling high impact resistance and high impact resistance at low temperatures.

[0044] R 1 The number of carbon atoms in the alkyl group is preferably 4 or 6 or more, preferably 12 or less, and more preferably 10 or less. 1 The alkyl group may be linear or branched. Among them, R 1 It is preferable that is 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 it is preferable that the terminal structure in general formula (1) is a t-octylphenyl group (i.e., a 1,1,3,3-tetramethylbutylphenyl group).

[0045] In formula (1) above, -(O) bonded to the phenyl group n R 1 The group can be in the ortho, meta, or para position, but the para position shown in equation (1') below is preferable. [ka]

[0046] R represented by the above formula (1) or (1') 1Specific examples of the groups include alkylphenyl groups such as pt-butyl group, pt-butylphenyl group, p-pentylphenyl group, p-hexylphenyl group, p-heptylphenyl group, pn-octylphenyl group, p-iso-octylphenyl group, pt-octylphenyl group, p-dodecylphenyl group and p-tetradecylphenyl group, p-nonylphenyl group, amylphenyl group, decylphenyl group, myristylphenyl group, and alkoxyphenyl groups such as p-hexyloxyphenyl group, pn-octyloxyphenyl group, p-iso-octyloxyphenyl group, pt-octyloxyphenyl group, and p-dodecyloxyphenyl group. R represented by equation (1) or (1') 1 The group is preferably a pt-butyl group, n-octyl group, iso-octyl group, or t-octyl group, more preferably a pt-butyl group, pn-octyl group, p-iso-octyl group, or pt-octyl group, and is particularly preferred because it can achieve a high degree of fluidity, enabling high impact resistance and low-temperature impact resistance.

[0047] When a polycarbonate resin having the terminal structure of formula (1) above is included, the proportion is preferably 40% by mass or more, and also preferably 100% by mass, out of 100% by mass of the total polycarbonate resin (A).

[0048] The molecular weight of the polycarbonate resin (A) is preferably 10,000 to 50,000 in viscosity-average molecular weight (Mv), more preferably 10,000 to 40,000, more preferably 10,000 to 30,000 and 10,000 to 26,000, even more preferably 10,500 or more, 11,000 or more, particularly 11,500 or more, most preferably 12,000 or more, even more preferably 24,000 or less, and particularly preferably 20,000 or less. By setting the viscosity-average molecular weight to be above the lower limit of the above range, the mechanical strength of the polycarbonate resin composition can be further improved, and by setting the viscosity-average molecular weight to be below the upper limit of the above range, the decrease in fluidity of the polycarbonate resin composition can be suppressed and improved, thereby enhancing moldability and facilitating molding. Furthermore, two or more polycarbonate resins with different viscosity-average molecular weights may be mixed and used. In this case, polycarbonate resins whose viscosity-average molecular weight is outside the preferred range described above may also be mixed.

[0049] The viscosity-average molecular weight [Mv] is calculated by using methylene chloride as the solvent, determining the intrinsic viscosity [η] (unit: dl / g) at 25°C using an Ubbelohde viscometer, and then using Schnell's viscosity formula, i.e., η = 1.23 × 10⁻⁶. -4 Mv 0.83 It refers to the value calculated from [the formula]. In addition, intrinsic viscosity [η] is the specific viscosity [η] at each solution concentration [C] (g / dl). sp This value was calculated by measuring [the value] and using the following formula.

number

[0050] Furthermore, in order to improve the appearance and fluidity of the molded article, the polycarbonate resin (A) may contain polycarbonate oligomers. The viscosity-average molecular weight [Mv] of these polycarbonate oligomers is usually 1,500 or more, preferably 2,000 or more, and usually 9,500 or less, preferably 9,000 or less. Moreover, it is preferable that the amount of polycarbonate oligomers contained be 30% by mass or less of the total amount of polycarbonate resin and polycarbonate oligomers.

[0051] Furthermore, the polycarbonate resin (A) may be made not only from virgin raw materials but also from polycarbonate resin recycled from used products (so-called material-recycled polycarbonate resin), and it is preferable to contain both virgin raw materials and recycled resin, or to consist solely of recycled polycarbonate resin. When using recycled polycarbonate resin, it is preferable that it accounts for 5% or more of the polycarbonate resin (A).

[0052] [Phosphorus stabilizer (C)] The polycarbonate resin composition preferably contains a phosphorus-based stabilizer (C). The inclusion of a phosphorus-based stabilizer results in a better hue for the light guide member of the present invention and further improves its heat resistance to discoloration. Any known phosphorus-based stabilizer can be used. Specific examples include phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, polyphosphate, and other phosphorus oxoacids; acidic pyrophosphate metal salts such as sodium acidic pyrophosphate, potassium acidic pyrophosphate, and calcium acidic pyrophosphate; phosphates of Group 1 or Group 2 metals such as potassium phosphate, sodium phosphate, cesium phosphate, and zinc phosphate; phosphate compounds, phosphite compounds, and phosphonite compounds are examples, but phosphite compounds, i.e., compounds having a phosphite structure, are particularly preferred. By selecting a phosphite compound, a polycarbonate resin composition with higher discoloration resistance and continuous productivity can be obtained.

[0053] Here, the phosphite compound is a trivalent phosphorus compound having a structure represented by the general formula: P(OR)3, where 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, distearylpentaerythritol diphosphite, bis(2,4- Examples include 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, and 6-[3-(3-tert-butyl-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]-dioxaphosfepine.

[0054] Among such phosphite compounds, aromatic phosphite compounds represented by the following formulas (1) or (2) are more preferred because they effectively enhance the heat resistance and color change properties of the light guide member of the present invention.

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

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

[0057] Among the phosphite compounds represented by the above formula (1), triphenyl phosphite, tris(mononylphenyl) phosphite, and tris(2,4-di-tert-butylphenyl) phosphite are particularly preferred, with tris(2,4-di-tert-butylphenyl) phosphite being more preferred. Specific examples of such organic phosphite compounds include "ADEKA Stab 1178" manufactured by ADEKA, "Sumilyzer TNP" manufactured by Sumitomo Chemical Co., Ltd., "JP-351" manufactured by Johoku Chemical Industry Co., Ltd., "ADEKA Stab 2112" manufactured by ADEKA, "Irgaphos 168" manufactured by BASF, and "JP-650" manufactured by Johoku Chemical Industry Co., Ltd.

[0058] Among the phosphite compounds having a spiro-ring skeleton represented by formula (2) above, 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, for example, "ADEKA Stab PEP-36" and "ADEKA Stab PEP-24G" manufactured by ADEKA Corporation, and "Doverphos S-9228" manufactured by Doverchemical Corporation.

[0059] Among phosphite compounds, aromatic phosphite compounds represented by formula (2) above are more preferred because they have superior hue. Furthermore, the phosphorus-based stabilizer may contain one type, or two or more types in any combination and ratio. It is more preferable that the phosphorus-based stabilizer (C) contains two or more phosphorus compounds having a phosphite structure, and that one or more of them are phosphite compounds having a spiro-ring skeleton.

[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, even more preferably 0.4 parts by mass or less, even more preferably 0.3 parts by mass or less, most preferably 0.2 parts by mass or less, and particularly preferably 0.1 parts by mass or less, per 100 parts by mass of 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, and if the content of the phosphorus-based stabilizer (C) exceeds 0.5 parts by mass, the heat discoloration resistance tends to worsen, and the moist heat stability also tends to decrease.

[0061] [Epoxy compounds and / or oxetane compounds (D)] The polycarbonate resin composition used in the present invention may also preferably contain an epoxy compound and / or an oxetane compound (D). The inclusion of the epoxy compound and / or oxetane compound (D) can further improve heat discoloration resistance. The content of the epoxy compound and / or oxetane compound (D) is preferably 0.0005 to 0.2 parts by mass per 100 parts by mass of the polycarbonate resin (A).

[0062] Epoxy compounds used are those having one or more epoxy groups in one molecule. Specifically, these include phenyl glycidyl ether, allyl glycidyl ether, t-butylphenyl glycidyl ether, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexyl carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-6'-methylcyclohexyl carboxylate, 2,3-epoxycyclohexylmethyl-3',4'-epoxycyclohexyl carboxylate, and 4-(3,4-epoxy-5-methylcyclohexyl)butyl-3',4'-epoxy Xycyclohexyl carboxylate, 3,4-epoxycyclohexylethylene oxide, cyclohexylmethyl 3,4-epoxycyclohexyl carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6'-methylcyclohexyl carboxylate, bisphenol-A diglycidyl ether, tetrabromobisphenol-A glycidyl ether, diglycidyl ester of phthalate, diglycidyl ester of hexahydrophthalate, bis-epoxydicyclopentadienyl ether, bis-epoxy Diylene glycol, bis-epoxycyclohexyl adipate, butadiene diepoxide, tetraphenylethylene epoxide, octyl epoxytalate, 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-epoxycyclohexyl carboxylate, N-butyl-2,2-dimethyl-3,4-epoxycyclohexyl carboxylate Xylate, cyclohexyl-2-methyl-3,4-epoxycyclohexyl carboxylate, N-butyl-2-isopropyl-3,4-epoxy-5-methylcyclohexyl carboxylate, octadecyl-3,4-epoxycyclohexyl carboxylate, 2-ethylhexyl-3',4'-epoxycyclohexyl carboxylate, 4,6-dimethyl-2,3-epoxycyclohexyl-3',4'-epoxycyclohexyl carboxylate, 4,5-epoxy tetrahydrophthalic anhydride, 3-t-butyl-4,Preferred examples include 5-epoxy tetrahydrophthalic anhydride, diethyl 4,5-epoxy-cis-1,2-cyclohexyl dicarboxylate, di-n-butyl-3-t-butyl-4,5-epoxy-cis-1,2-cyclohexyl dicarboxylate, epoxidized soybean oil, and epoxidized linseed oil.

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

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

[0065] Examples of polyalkylene glycol derivatives containing epoxy groups in their structure include, for example, 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] Epoxy compounds may be used individually or in combination of two or more types.

[0067] The preferred content of the epoxy compound is 0.0005 to 0.2 parts by mass per 100 parts by mass of polycarbonate resin (A), more preferably 0.001 parts by mass or more, even more preferably 0.003 parts by mass or more, even more preferably 0.005 parts by mass or more, particularly preferably 0.01 parts by mass or more, and more preferably 0.15 parts by mass or less, even more preferably 0.1 parts by mass or less, particularly preferably 0.05 parts by mass or less. If the epoxy compound content is less than 0.0005 parts by mass, the hue and heat discoloration resistance tend to be insufficient, and if it exceeds 0.2 parts by mass, the heat discoloration resistance tends to worsen, and the hue and moist heat stability also tend to decrease.

[0068] Any oxetane compound having one or more oxetane groups in its molecule can be used, including monooxetane compounds having one oxetane group in their molecule and bifunctional or polyoxetane compounds having two or more oxetane groups in their molecule. By including an oxetane compound, it is possible to further improve the good hue and high heat resistance to discoloration.

[0069] Examples of monooxetane compounds include those represented by the following general formulas (3), (4), or (5).

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

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

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

[0073] In the above general formula (5), R 3This is a divalent organic group that may have an aromatic ring. Examples include linear or branched alkylene groups having 1 to 12 carbon atoms, such as ethylene, propylene, butylene, neopentylene, n-pentamethylene, and n-hexamethylene; phenylene; divalent groups represented by the formula -CH2-Ph-CH2- or -CH2-Ph-Ph-CH2- (where Ph represents the phenyl group); hydrogenated bisphenol A residues, hydrogenated bisphenol F residues, hydrogenated bisphenol Z residues, cyclohexanedimethanol residues, and tricyclodecanedimethanol residues.

[0074] Particularly preferred examples of the compound of the above 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] Oxetane compounds may be used alone or in combination of two or more types.

[0076] When an oxetane compound is included, the content is preferably 0.0005 to 0.2 parts by mass, more preferably 0.001 parts by mass or more, even more preferably 0.003 parts by mass or more, even more preferably 0.005 parts by mass or more, particularly preferably 0.01 parts by mass or more, and more preferably 0.15 parts by mass or less, even more preferably 0.1 parts by mass or less, particularly preferably 0.05 parts by mass or less. If the content of the oxetane compound is less than 0.0005 parts by mass, the hue and heat discoloration resistance tend to be insufficient, and if it exceeds 0.2 parts by mass, the heat discoloration resistance tends to worsen, and gas is more likely to be generated during molding.

[0077] It is preferable to contain both the epoxy compound and the oxetane compound together, and if both are included, the total content is preferably 0.0005 to 0.2 parts by mass per 100 parts by mass of polycarbonate resin (A). More preferably 0.001 parts by mass or more, even more preferably 0.003 parts by mass or more, even more preferably 0.005 parts by mass or more, particularly preferably 0.01 parts by mass or more, and also more preferably 0.15 parts by mass or less, even more preferably 0.1 parts by mass or less, particularly preferably 0.05 parts by mass or less.

[0078] [Fatty acid ester (E)] The polycarbonate resin composition preferably contains fatty acid ester (E). The inclusion of fatty acid ester (E) is preferable because it results in a good color. Fatty acid esters (E) are esters of aliphatic carboxylic acids and alcohols.

[0079] Examples of aliphatic carboxylic acids in esters of aliphatic carboxylic acids with alcohols include saturated or unsaturated monovalent, divalent, or trivalent aliphatic carboxylic acids. Here, aliphatic carboxylic acids also include alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are monovalent or divalent carboxylic acids having 6 to 36 carbon atoms, and more preferably saturated monovalent aliphatic carboxylic acids having 6 to 36 carbon atoms. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetrariacontanoic acid, montanic acid, adipic acid, and azelaic acid.

[0080] Examples of alcohols in esters of aliphatic carboxylic acids include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have substituents such as fluorine atoms or aryl groups. Among these, monohydric or polyhydric saturated alcohols with 30 or fewer carbon atoms are preferred, and aliphatic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols with 30 or fewer carbon atoms are more preferred. Here, "aliphatic" is used as a term that also includes 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] Furthermore, the above-mentioned esters may contain aliphatic carboxylic acids and / or alcohols as impurities. Also, the above-mentioned esters may be pure substances or mixtures of multiple compounds. Moreover, the aliphatic carboxylic acids and alcohols that combine to form a single ester may be used individually, or two or more may be used in any combination and ratio.

[0082] Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture mainly composed of myricyl palmitate), 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. These may be used individually or in any combination of two or more.

[0083] The fatty acid ester (E) content is preferably 0.005 to 0.5 parts by mass, and particularly preferably 0.01 to 0.1 parts by mass, per 100 parts by mass of polycarbonate resin (A).

[0084] [Additives, etc.] The polycarbonate resin composition used in the present invention may contain other additives besides those mentioned above, such as antioxidants, ultraviolet absorbers, fluorescent whitening agents, pigments, dyes, polymers other than polycarbonate resin, flame retardants, impact modifiers, antistatic agents, plasticizers, and compatibilizers. These additives may be blended one or more times. The polycarbonate resin composition used in the present invention preferably contains 50% by mass or more of polycarbonate resin (A), more preferably 55% by mass or more, and depending on the application, it may contain 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, or 90% by mass or more, and preferably 99% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, and even more preferably 85% by mass or less, and depending on the application, it may contain 80% by mass or less, 78% by mass or less, or 75% by mass or less. Furthermore, if other polymers besides polycarbonate resin (A) are included, their content 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 polycarbonate resin (A).

[0085] The polycarbonate resin composition used in the present invention can be obtained by pre-mixing a polycarbonate resin (A), a polylactone-polyether copolymer (B), and other components as needed, using various mixers such as a tumbler or Henschel mixer, and then melt-kneading them in a mixer such as a Banbury mixer, roll mixer, Brabender, single-screw extruder, twin-screw extruder, or kneader. The melt-kneading temperature is not particularly limited, but is usually in the range of 240 to 320°C. The polycarbonate resin composition used in the present invention is excellent in transparency, fluidity, hue, and impact resistance, and generates very little gas and contaminates the mold during molding, making it particularly suitable for molding light guide members, especially thin-walled light guide members which are prone to mold contamination. Furthermore, the aromatic polycarbonate resin composition of the present invention has excellent hue and therefore excellent YI (degree of yellowing), and a molded article can be obtained in which the YI value at a 300 mm optical path length is preferably 20 or less, more preferably 19 or less, most preferably 18 or less, even more preferably 16 or less, and particularly preferably 15 or less.

[0086] [Manufacturing method for light guide members] The light guide member of the present invention is obtained by molding the above-mentioned polycarbonate resin composition (usually in the form of pellets thereof). There are no restrictions on the manufacturing method of the light guide member, but in order to obtain a light guide member with excellent mechanical strength, dimensional accuracy, etc., injection molding, extrusion molding, press molding, blow molding, etc. are recommended, but injection molding is preferred from the viewpoint of mechanical strength and dimensional stability. When using injection molding, the resin composition temperature is preferably higher than the 260-300°C temperature generally applied to injection molding of polycarbonate resins, especially in the case of thin-walled molded articles, with a resin composition temperature of 305-400°C being preferred. The resin composition temperature is more preferably 310°C or higher, even more preferably 315°C or higher, particularly preferably 320°C or higher, and most preferably 390°C or lower. With conventional polycarbonate resin compositions, there was a problem that increasing the resin temperature during molding to form thin-walled molded articles made the molded articles prone to yellowing. However, by using the above-mentioned polycarbonate resin composition, it is possible to manufacture light guide members with good hue and high transparency even within the above temperature range. If the resin composition temperature is difficult to measure directly, it is determined as the barrel setting temperature.

[0087] As the light guide member, a thin-walled molded body is preferred, where a thin-walled molded body refers to a molded body having a plate-like portion with a wall thickness of usually 1 mm or less, preferably 0.8 mm or less, and more preferably 0.6 mm or less. Here, the plate-like portion may be a flat plate or a curved plate, may have a flat surface or may have irregularities on its surface, and may have an inclined surface in its cross-section, or a wedge-shaped shape in which the thickness changes sequentially in the length direction, or a wedge-shaped cross-section, etc. A light guide member is a member that has a light source (e.g., LED, organic EL, incandescent bulb, fluorescent lamp, cathode tube, etc., particularly an LED light source) placed on one side or back surface, and directs the light from the light source into the light guide member, causing it to reflect and refract while guiding and / or emitting light. Preferred light guide members include light guide plates, surface light emitting materials, light guide films, light guide sheets, and vehicle light guides (e.g., light guides for automobile lamps), with light guide plates being particularly preferred. Light guide plates can be suitably used in the fields of liquid crystal backlight units, various display devices, and lighting devices, and can be particularly suitably used as high-performance edge-lit type light guide plates. The light guide member preferably has an optical path length of 30 mm or more, and more preferably 50 mm or more.

[0088] Examples of light guide films or sheets include those with a thickness of less than 1 mm, preferably 0.8 mm or less, more preferably 0.5 mm or less, even more preferably 0.4 mm or less, and particularly preferably 0.3 mm or less. Examples of light guide plates include those with a thickness of less than 3 mm, preferably 2 mm or less, more preferably 1 mm or less, preferably 0.3 mm or more, and particularly preferably 0.4 mm or more, but are not limited to these.

[0089] The light guide member of the present invention does not exhibit clouding or a decrease in transmittance, has good hue and high transparency, and exhibits fewer molding defects due to mold contamination during molding. [Examples]

[0090] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples. The raw materials used in the following examples and comparative examples are shown in Table 1.

[0091] [Table 1]

[0092] (Examples 1-14, Comparative Examples 1-4) [Manufacturing of resin composition pellets] Each of the above components was blended in the proportions (parts by mass) shown in Table 2 and below, mixed in a tumbler for 20 minutes, and then melt-kneaded at a cylinder temperature of 240°C using a vented single-screw extruder with a screw diameter of 40 mm (Tanabe Plastic Machinery Co., Ltd. "VS-40"). The mixture was then extruded as strands through the nozzle of the die at the tip of the extruder, and the strands were cut in a pelletizer to obtain pellets.

[0093] [Hue (YI)] The obtained pellets were dried at 120°C for 5 to 7 hours in a hot air circulation dryer. Then, using an injection molding machine (Sodick "HSP100A"), a long-path molded product (300 mm x 7 mm x 4 mm thick) was molded at a resin composition temperature of 340°C and a mold temperature of 80°C for evaluation as a light guide component. For this long-path molded product, the degree of yellowing (YI) was measured with a 300 mm optical path length. A long-path spectrophotometer (ASA 1, manufactured by Nippon Denshoku Industries, Ltd., C light source, 2° field of view) was used for the measurement. The evaluation results are shown in Table 2-5 below.

[0094] [Table 2]

[0095] [Table 3]

[0096] [Table 4]

[0097] [Table 5]

[0098] As shown in the table above, the long-path molded product of the example has a small YI value, indicating that it is suitable as a light guide member. Furthermore, Table 4 shows that when the same polycarbonate resin A3 is used, Example 13, in which the molar ratio of lactone units to ether units in the polylactone-polyether copolymer falls within the range of the present invention, has a lower YI value than Comparative Example 3, in which the molar ratio falls outside the range. Similarly, Table 5 shows that when polycarbonate resins A1 and A4 are used, Example 14, in which the molar ratio of lactone units to ether units in the polylactone-polyether copolymer falls within the range of the present invention, has a lower YI value than Comparative Example 4, in which the molar ratio falls outside the range. [Industrial applicability]

[0099] The light guide member of the present invention is a light guide member with a low YI value and extremely good hue and transparency, and can be suitably used in various light guide members.

Claims

1. A light guide member molded from a polycarbonate resin composition containing 0.01 to 4 parts by mass of polylactone-polyether copolymer (B) per 100 parts by mass of polycarbonate resin (A), characterized in that the molar ratio of lactone units to ether units of the polylactone-polyether copolymer (B) is 30 to 95:70 to 5.

2. The light guide member according to claim 1, wherein the polylactone-polyether copolymer (B) is a polycaprolactone-polyether copolymer.

3. The light guide member according to claim 2, wherein the polycaprolactone-polyether copolymer (B) is a polycaprolactone-polyether copolymer represented by the following general formula (I) or (II). 【Chemistry 1】 【Chemistry 2】 In formulas (I) and (II), each of R1 to R4 represents a linear or branched hydrocarbon group having 2 to 20 carbon atoms, which may be substituted with an allyloxy group or an alkoxy group, and R5 is CH ２ CHCH ２ 、CH ３ C(CH ２ ) ３ 、or CH ３ CH ２ C(CH ２ ) ３ . a represents an integer of 3 or more, b and c each represent an integer of 1 or more, and l, m, n, o, p, and q each represent an integer of 1 or more.]

4. The light guide member according to claim 3, wherein R1 to R4 in the above general formulas (I) and (II) are alkylene groups selected from the group consisting of 1,2-ethylene group, 1,2-propylene group, trimethylene group, 1,2-butylene group and tetramethylene group.

5. The light guide member according to claim 1, wherein the number average molecular weight (Mn) of the polylactone-polyether copolymer (B) is 200 to 10,000.

6. The light guide member according to claim 1 or 2, wherein the viscosity-average molecular weight (Mv) of the polycarbonate resin (A) is 10,000 to 50,000.

7. The light guide member according to claim 1 or 2, wherein the polycarbonate resin composition further contains a phosphorus-based stabilizer (C) in an amount of 0.005 to 0.5 parts by mass per 100 parts by mass of the polycarbonate resin (A).

8. The light guide member according to claim 7, wherein the phosphorus-based stabilizer (C) is a phosphorus-based compound having a phosphite structure.

9. The light guide member according to claim 8, wherein the phosphorus-based stabilizer (C) contains two or more phosphorus-based compounds having a phosphite structure, and one or more of these compounds are phosphite compounds having a spiro-ring skeleton.

10. The light guide member according to claim 1, wherein the polycarbonate resin composition further contains an epoxy compound and / or an oxetane compound (D) in an amount of 0.0005 to 0.2 parts by mass per 100 parts by mass of the polycarbonate resin (A).

11. The light guide member according to claim 1 or 2, wherein the polycarbonate resin composition further contains 0.005 to 0.5 parts by mass of fatty acid ester (E) per 100 parts by mass of polycarbonate resin (A).

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