JP2018028025A - Polycarbonate resin composition for optical members - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition for optical components that has a good hue and high thermal discoloration resistance, and also has an extremely low level of die contamination during molding.SOLUTION: A polycarbonate resin composition for optical members contains, based on a polycarbonate resin (A) 100 pts.mass, a polyalkylene glycol compound (B) with a number average molecular weight of 500-5000 of 0.1-2 pts.mass, and an oxetane compound (C) of 0.001-0.2 pts.mass.SELECTED DRAWING: None

Description

  The present invention relates to a polycarbonate resin composition for an optical member, and more particularly to a polycarbonate resin composition for an optical member having a good hue and a high degree of heat discoloration and extremely little mold contamination during molding.

  As the optical member, for example, the light guide plate is used in an illumination unit such as a backlight unit of various display devices. Recently, there has been a demand for a display device that displays a clearer image, and there is a tendency for the temperature inside the device to increase due to the heat generated in the vicinity of the light source, so that it is being replaced with a polycarbonate resin material with higher heat resistance.

  However, when the polycarbonate resin composition is used for the light guide plate, a light guide plate having a good hue can be obtained when the molding temperature is low, but the molding temperature is increased to ensure sufficient melt fluidity for thinning the light guide plate. Then, due to the thermal deterioration of the carbonate resin, there is a problem that the color tone of the obtained light guide plate is yellowish or a good hue is easily lost.

In Patent Document 1, a resin composition in which a diphosphite compound and an alicyclic epoxy compound are blended with an aromatic polycarbonate resin having a viscosity average molecular weight of 10,000 to 15,000 includes a light transmittance, luminance, and heat in high temperature molding. Excellent stability, and even when exposed to high temperature and high humidity for a long time, discoloration and deterioration do not occur, and a molded product with excellent light transmission can be obtained. Optically molded products, especially as light guide plates It has been proposed to be useful.
However, in the resin composition of Patent Document 1, there is a possibility that the transmittance is improved by adding an alicyclic epoxy, but the effect of improving the hue is not necessarily sufficient.

  In recent years, various types of mobile terminals such as smartphones and tablet terminals have become increasingly thin and large-sized, and an edge type that uses light from the direct side to the side edge is used. Therefore, in such an optical member such as a high-end light guide plate, it is required to have a better hue and a high degree of heat discoloration.

  In recent years, in Europe, North America, etc., daylights that are constantly lit on the headlamps and rear lamps of automobiles have been installed to improve visibility from daytime pedestrians and oncoming vehicles. It is out. The daylight generally includes a light guide member and a light source that causes light to enter the light guide member. An incandescent lamp such as a halogen lamp is generally provided near the daylight of an automobile as a normal light source for nighttime. Therefore, the light guide member is an incandescent lamp in addition to the heat generated from the daylight light source. It is also heated by the heat generated from. For this reason, the more excellent heat-resistant durability is calculated | required by the light guide member for motor vehicles.

  Further, when molding a polycarbonate resin composition for an optical member, the occurrence of mold deposits is a big problem. In particular, when molding a high-performance light guide member, it is compelled to frequently perform mold cleaning maintenance.

Japanese Patent No. 5938419

  The present invention has been made in view of the above circumstances, and its object (problem) is to have a good hue and a high degree of heat discoloration without impairing the original properties of the polycarbonate resin, and to be used for molding. An object of the present invention is to provide a polycarbonate resin composition for an optical member with very little mold contamination.

As a result of intensive studies to achieve the above problems, the present inventor solved the above problems by blending polyalkylene glycol compounds having a specific number average molecular weight and oxetane compounds in specific amounts, respectively. The present inventors have found that this can be done and have completed the present invention.
The present invention relates to the following polycarbonate resin composition for optical members.

[1] 0.1 to 2 parts by mass of a polyalkylene glycol compound (B) having a number average molecular weight of 500 to 5000 and 0.001 to 0.001 of an oxetane compound (C) with respect to 100 parts by mass of the polycarbonate resin (A). A polycarbonate resin composition for optical members, comprising 2 parts by mass.
[2] The polycarbonate resin composition for an optical member according to the above [1], wherein the oxetane compound (C) is a compound represented by the following general formula (Ia), (Ib) or (II).
(Wherein R ¹ represents an alkyl group, R ² represents an alkyl group or a phenyl group, R ³ represents a divalent organic group which may have an aromatic ring, and n represents 0 or 1)

[3] The polycarbonate resin composition for an optical member according to the above [1] or [2], wherein the oxetane function in the oxetane compound (C) is bifunctional or higher.
[4] Any of [1] to [3] above, wherein the mass ratio (C) / (B) of the content of the oxetane compound (C) and the polyalkylene glycol compound (B) is 0.005 to 0.2. A polycarbonate resin composition for an optical member according to claim 1.
[5] A light guide plate comprising the polycarbonate resin composition according to any one of [1] to [4].
[6] A vehicle lamp light guide member comprising the polycarbonate resin composition according to any one of [1] to [4].

  The polycarbonate resin composition of the present invention is capable of providing an optical member having a good hue and high heat discoloration resistance without deteriorating the original properties of the polycarbonate resin, with very little mold contamination during molding. it can.

It is a top view of the drop mold used for evaluation of mold contamination in an example.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples.
In the present specification, “to” is used in the sense of including the numerical values described before and after the lower and upper limits unless otherwise specified.

In the polycarbonate resin composition for an optical member of the present invention, 0.1 to 2 parts by mass of a polyalkylene glycol compound (B) having a number average molecular weight of 500 to 5000 and 100 parts by mass of a polycarbonate resin (A), an oxetane compound ( C) is contained in an amount of 0.001 to 0.2 parts by mass.
Hereinafter, the present invention will be described in detail.

[Polycarbonate resin (A)]
There is no restriction | limiting in the kind of polycarbonate resin used in this invention, A polycarbonate resin may use 1 type and may use 2 or more types together by arbitrary combinations and arbitrary ratios.

The polycarbonate resin is a polymer having a basic structure having a carbonic acid bond represented by the formula: — [— O—X—O—C (═O) —] —.
In the formula, X is generally a hydrocarbon, but for imparting various properties, X into which a hetero atom or a hetero bond is introduced may be used.

  The polycarbonate resin can be classified into an aromatic polycarbonate resin in which carbon directly bonded to a carbonic acid bond is aromatic carbon and an aliphatic polycarbonate resin in which aliphatic carbon is aliphatic carbon, either of which can be used. Of these, aromatic polycarbonate resins are preferred from the viewpoints of heat resistance, mechanical properties, electrical characteristics, and the like.

  Although there is no restriction | limiting in the specific kind of polycarbonate resin, For example, the polycarbonate polymer formed by making a dihydroxy compound and a carbonate precursor react is mentioned. At this time, in addition to the dihydroxy compound and the carbonate precursor, a polyhydroxy compound or the like may be reacted. Further, a method of reacting carbon dioxide with a cyclic ether using a carbonate precursor may be used. The polycarbonate polymer may be linear or branched. Further, the polycarbonate polymer may be a homopolymer composed of one type of repeating unit or a copolymer having two or more types of repeating units. At this time, the copolymer can be selected from various copolymerization forms such as a random copolymer and a block copolymer. In general, such a polycarbonate polymer is a thermoplastic resin.

Among monomers used as raw materials for aromatic polycarbonate resins, examples of aromatic dihydroxy compounds include:
Dihydroxybenzenes such as 1,2-dihydroxybenzene, 1,3-dihydroxybenzene (ie, resorcinol), 1,4-dihydroxybenzene;
Dihydroxybiphenyls such as 2,5-dihydroxybiphenyl, 2,2′-dihydroxybiphenyl, 4,4′-dihydroxybiphenyl;

2,2′-dihydroxy-1,1′-binaphthyl, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, , 7-dihydroxynaphthalene, dihydroxynaphthalene such as 2,7-dihydroxynaphthalene;

2,2′-dihydroxydiphenyl ether, 3,3′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, 1,4-bis (3-hydroxyphenoxy) Dihydroxy diaryl ethers such as benzene and 1,3-bis (4-hydroxyphenoxy) benzene;

2,2-bis (4-hydroxyphenyl) propane (ie, bisphenol A),
1,1-bis (4-hydroxyphenyl) propane,
2,2-bis (3-methyl-4-hydroxyphenyl) propane,
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;

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;

9,9-bis (4-hydroxyphenyl) fluorene,
Cardio structure-containing bisphenols such as 9,9-bis (4-hydroxy-3-methylphenyl) fluorene;

4,4′-dihydroxydiphenyl sulfide,
Dihydroxydiaryl sulfides such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide;

Dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide;

4,4′-dihydroxydiphenyl sulfone,
Dihydroxydiaryl sulfones such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone;
Etc.

Among these, bis (hydroxyaryl) alkanes are preferable, and bis (4-hydroxyphenyl) alkanes are particularly preferable, and 2,2-bis (4-hydroxyphenyl) propane (especially from the viewpoint of impact resistance and heat resistance). That is, bisphenol A) is preferred.
In addition, 1 type may be used for an aromatic dihydroxy compound and it may use 2 or more types together by arbitrary combinations and a ratio.

In addition, when an example of a monomer that is a raw material of the aliphatic polycarbonate resin is given,
Ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, 2,2-dimethylpropane-1,3-diol, 2-methyl-2-propylpropane-1,3- Alkanediols such as diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, decane-1,10-diol;

  Cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol, 1,4-cyclohexanedimethanol, 4- (2-hydroxyethyl) cyclohexanol, 2,2,4, Cycloalkanediols such as 4-tetramethyl-cyclobutane-1,3-diol;

  Glycols such as ethylene glycol, 2,2'-oxydiethanol (ie, diethylene glycol), triethylene glycol, propylene glycol, spiro glycol and the like;

  1,2-benzenedimethanol, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 1,4-benzenediethanol, 1,3-bis (2-hydroxyethoxy) benzene, 1,4-bis ( 2-hydroxyethoxy) benzene, 2,3-bis (hydroxymethyl) naphthalene, 1,6-bis (hydroxyethoxy) naphthalene, 4,4′-biphenyldimethanol, 4,4′-biphenyldiethanol, 1,4- Aralkyl diols such as bis (2-hydroxyethoxy) biphenyl, bisphenol A bis (2-hydroxyethyl) ether, bisphenol S bis (2-hydroxyethyl) ether;

  1,2-epoxyethane (ie ethylene oxide), 1,2-epoxypropane (ie propylene oxide), 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,4-epoxycyclohexane, 1-methyl And cyclic ethers such as -1,2-epoxycyclohexane, 2,3-epoxynorbornane, and 1,3-epoxypropane;

  Among the monomers used as the raw material for the polycarbonate resin, carbonyl halides, carbonate esters and the like are used as examples of the carbonate precursor. In addition, 1 type may be used for a carbonate precursor and it may use 2 or more types together by arbitrary combinations and a ratio.

  Specific examples of carbonyl halides include phosgene; haloformates such as bischloroformate of dihydroxy compounds and monochloroformate of dihydroxy compounds.

  Specific examples of the carbonate ester include diaryl carbonates such as diphenyl carbonate and ditolyl carbonate; dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; biscarbonate bodies of dihydroxy compounds, monocarbonate bodies of dihydroxy compounds, and cyclic carbonates. And carbonate bodies of dihydroxy compounds such as

Manufacturing method of polycarbonate resin The manufacturing method of polycarbonate resin is not specifically limited, Arbitrary methods are employable. Examples thereof include an interfacial polymerization method, a melt transesterification method, a pyridine method, a ring-opening polymerization method of a cyclic carbonate compound, and a solid phase transesterification method of a prepolymer.
Hereinafter, a particularly preferable one of these methods will be described in detail.

Interfacial Polymerization Method First, a case where a polycarbonate resin is produced by an interfacial polymerization method will be described.
In the interfacial polymerization method, a dihydroxy compound and a carbonate precursor (preferably phosgene) are reacted in the presence of an organic solvent inert to the reaction and an aqueous alkaline solution, usually at a pH of 9 or higher. Polycarbonate resin is obtained by interfacial polymerization in the presence. In the reaction system, a molecular weight adjusting agent (terminal terminator) may be present as necessary, or an antioxidant may be present to prevent the oxidation of the dihydroxy compound.

  The dihydroxy compound and the carbonate precursor are as described above. Of the carbonate precursors, phosgene is preferably used, and a method using phosgene is particularly called a phosgene method.

  Examples of the organic solvent inert to the reaction include chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane, chloroform, monochlorobenzene and dichlorobenzene; aromatic hydrocarbons such as benzene, toluene and xylene; It is done. In addition, 1 type may be used for an organic solvent and it may use 2 or more types together by arbitrary combinations and a ratio.

  Examples of the alkali compound contained in the alkaline aqueous solution include alkali metal compounds and alkaline earth metal compounds such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and sodium hydrogen carbonate, among which sodium hydroxide and water Potassium oxide is preferred. In addition, 1 type may be used for an alkali compound and it may use 2 or more types together by arbitrary combinations and a ratio.

  Although there is no restriction | limiting in the density | concentration of the alkali compound in alkaline aqueous solution, Usually, in order to control pH in the alkaline aqueous solution of reaction to 10-12, it is used at 5-10 mass%. For example, when phosgene is blown, the molar ratio of the bisphenol compound and the alkali compound is usually 1: 1.9 or more in order to control the pH of the aqueous phase to be 10 to 12, preferably 10 to 11. Among these, it is preferable that the ratio is 1: 2.0 or more, usually 1: 3.2 or less, and more preferably 1: 2.5 or less.

  Examples of the polymerization catalyst include aliphatic tertiary amines such as trimethylamine, triethylamine, tributylamine, tripropylamine, and trihexylamine; alicyclic rings such as N, N′-dimethylcyclohexylamine and N, N′-diethylcyclohexylamine. Formula tertiary amines; aromatic tertiary amines such as N, N′-dimethylaniline and N, N′-diethylaniline; quaternary ammonium salts such as trimethylbenzylammonium chloride, tetramethylammonium chloride, triethylbenzylammonium chloride, etc. Pyridine; guanine; guanidine salt; and the like. In addition, 1 type may be used for a polymerization catalyst and it may use 2 or more types together by arbitrary combinations and a ratio.

  Examples of the molecular weight regulator include aromatic phenols having a monohydric phenolic hydroxyl group; aliphatic alcohols such as methanol and butanol; mercaptans; phthalimides and the like. Of these, aromatic phenols are preferred. Specific examples of such aromatic phenols include alkyl groups such as m-methylphenol, p-methylphenol, m-propylphenol, p-propylphenol, p-tert-butylphenol, and p-long chain alkyl-substituted phenol. Examples thereof include substituted phenols; vinyl group-containing phenols such as isopropanyl phenol; epoxy group-containing phenols; carboxyl group-containing phenols such as o-hydroxybenzoic acid and 2-methyl-6-hydroxyphenylacetic acid; In addition, a molecular weight regulator may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The usage-amount of a molecular weight regulator is 0.5 mol or more normally with respect to 100 mol of dihydroxy compounds, Preferably it is 1 mol or more, and is 50 mol or less normally, Preferably it is 30 mol or less. By making the usage-amount of a molecular weight modifier into this range, the thermal stability and hydrolysis resistance of a resin composition can be improved.

In the reaction, the order of mixing the reaction substrate, reaction medium, catalyst, additive and the like is arbitrary as long as a desired polycarbonate resin is obtained, and an appropriate order may be arbitrarily set. For example, when phosgene is used as the carbonate precursor, the molecular weight regulator can be mixed at any time as long as it is between the reaction (phosgenation) of the dihydroxy compound and phosgene and the start of the polymerization reaction.
In addition, reaction temperature is 0-40 degreeC normally, and reaction time is normally several minutes (for example, 10 minutes)-several hours (for example, 6 hours).

Next, a case where a polycarbonate resin is produced by a melt transesterification method will be described.
In the melt transesterification method, for example, a transesterification reaction between a carbonic acid diester and a dihydroxy compound is performed.

The dihydroxy compound is as described above.
On the other hand, examples of the carbonic acid diester include dialkyl carbonate compounds such as dimethyl carbonate, diethyl carbonate, and di-tert-butyl carbonate; diphenyl carbonate; substituted diphenyl carbonate such as ditolyl carbonate, and the like. Among these, diphenyl carbonate and substituted diphenyl carbonate are preferable, and diphenyl carbonate is more preferable. In addition, carbonic acid diester may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of the dihydroxy compound and the carbonic acid diester is arbitrary as long as the desired polycarbonate resin is obtained, but it is preferable to use an equimolar amount or more of the carbonic acid diester with respect to 1 mol of the dihydroxy compound, and above all, 1.01 mol or more. It is more preferable. The upper limit is usually 1.30 mol or less. By setting it as such a range, the amount of terminal hydroxyl groups can be adjusted to a suitable range.

  In the polycarbonate resin, the amount of terminal hydroxyl groups tends to have a great influence on thermal stability, hydrolysis stability, color tone and the like. For this reason, you may adjust the amount of terminal hydroxyl groups as needed by a well-known arbitrary method. In the transesterification reaction, a polycarbonate resin in which the amount of terminal hydroxyl groups is adjusted can be usually obtained by adjusting the mixing ratio of the carbonic diester and the aromatic dihydroxy compound; the degree of vacuum during the transesterification reaction, and the like. In addition, the molecular weight of the polycarbonate resin usually obtained can also be adjusted by this operation.

When adjusting the amount of terminal hydroxyl groups by adjusting the mixing ratio of the carbonic acid diester and the dihydroxy compound, the mixing ratio is as described above.
Further, as a more aggressive adjustment method, there may be mentioned a method in which a terminal terminator is mixed separately during the reaction. Examples of the terminal terminator at this time include monohydric phenols, monovalent carboxylic acids, carbonic acid diesters, and the like. In addition, 1 type may be used for a terminal terminator and it may use 2 or more types together by arbitrary combinations and a ratio.

  When producing a polycarbonate resin by the melt transesterification method, a transesterification catalyst is usually used. Any transesterification catalyst can be used. Among them, it is preferable to use, for example, an alkali metal compound and / or an alkaline earth metal compound. In addition, auxiliary compounds such as basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds may be used in combination. In addition, 1 type may be used for a transesterification catalyst and it may use 2 or more types together by arbitrary combinations and a ratio.

  In the melt transesterification method, the reaction temperature is usually 100 to 320 ° C. The pressure during the reaction is usually a reduced pressure condition of 2 mmHg or less. As a specific operation, a melt polycondensation reaction may be performed under the above-mentioned conditions while removing a by-product such as an aromatic hydroxy compound.

  The melt polycondensation reaction can be performed by either a batch method or a continuous method. In the case of a batch system, the order of mixing the reaction substrate, reaction medium, catalyst, additive, etc. is arbitrary as long as the desired polycarbonate resin is obtained, and an appropriate order may be set arbitrarily. However, considering the stability of the polycarbonate resin and the like, the melt polycondensation reaction is preferably carried out continuously.

  In the melt transesterification method, a catalyst deactivator may be used as necessary. As the catalyst deactivator, a compound that neutralizes the transesterification catalyst can be arbitrarily used. Examples thereof include sulfur-containing acidic compounds and derivatives thereof. In addition, 1 type may be used for a catalyst deactivator and it may use 2 or more types together by arbitrary combinations and a ratio.

  The amount of the catalyst deactivator used is usually 0.5 equivalents or more, preferably 1 equivalent or more, and usually 10 equivalents or less, relative to the alkali metal or alkaline earth metal contained in the transesterification catalyst. Preferably it is 5 equivalents or less. Furthermore, it is 1 ppm or more normally with respect to polycarbonate resin, and is 100 ppm or less normally, Preferably it is 20 ppm or less.

The molecular weight of the polycarbonate resin (A) is measured by a viscosity average molecular weight (Mv) converted from the solution viscosity measured at a temperature of 20 ° C. using methylene chloride as a solvent. In a light guide plate such as a backlight for liquid crystal, it is preferably 10,000 to 15,000, more preferably 10,500 or more, further preferably 11,000 or more, particularly 11,500 or more, and most preferably 12. , 000 or more, and more preferably 14,500 or less.
Further, in the case of a light guide or lens for guiding light from a light source such as an LED in a vehicle headlamp (rear lamp) or the like for an automobile or motorcycle, 15,000 to 23,000 is preferable, and fluidity / hue More preferably, it is 17,000-20,000.
By making the viscosity average molecular weight more than the lower limit of the above range, the mechanical strength of the polycarbonate resin composition of the present invention can be further improved, and by making the viscosity average molecular weight not more than the upper limit of the above range, The fluidity of the polycarbonate resin composition of the invention can be suppressed and improved, and the molding processability can be improved and the thin-wall molding process can be easily performed.
Two or more types of polycarbonate resins having different viscosity average molecular weights may be mixed and used, and in this case, a polycarbonate resin having a viscosity average molecular weight outside the above-mentioned preferred range may be mixed.

The viscosity average molecular weight [Mv] is obtained by using methylene chloride as a solvent and obtaining an intrinsic viscosity [η] (unit: dl / g) at a temperature of 20 ° C. using an Ubbelohde viscometer. , Η = 1.23 × 10 ⁻⁴ Mv ^0.83 . The intrinsic viscosity [η] is a value calculated from the following equation by measuring the specific viscosity [η _sp ] at each solution concentration [C] (g / dl).

  The terminal hydroxyl group concentration of the polycarbonate resin (A) is arbitrary and may be appropriately selected and determined, but is usually 1000 ppm or less, preferably 800 ppm or less, more preferably 600 ppm or less. Thereby, the residence heat stability and color tone of polycarbonate resin can be improved more. In addition, the lower limit is usually 10 ppm or more, preferably 30 ppm or more, more preferably 40 ppm or more, particularly for polycarbonate resins produced by the melt transesterification method. Thereby, the fall of molecular weight can be suppressed and the mechanical characteristic of a resin composition can be improved more.

  In addition, the unit of a terminal hydroxyl group density | concentration represents the mass of the terminal hydroxyl group with respect to the mass of polycarbonate resin in ppm. The measurement method is colorimetric determination (method described in Macromol. Chem. 88 215 (1965)) by the titanium tetrachloride / acetic acid method.

  The polycarbonate resin is a polycarbonate resin alone (the polycarbonate resin alone is not limited to an embodiment containing only one type of polycarbonate resin, and is used in a sense including an embodiment containing a plurality of types of polycarbonate resins having different monomer compositions and molecular weights, for example. .), Or an alloy (mixture) of a polycarbonate resin and another thermoplastic resin may be used in combination. Further, for example, for the purpose of further improving flame retardancy and impact resistance, a polycarbonate resin is copolymerized with an oligomer or polymer having a siloxane structure; for the purpose of further improving thermal oxidation stability and flame retardancy A monomer, oligomer or polymer having a copolymer; a monomer, oligomer or polymer having a dihydroxyanthraquinone structure for the purpose of improving thermal oxidation stability; A copolymer with an oligomer or polymer having an olefin structure; a copolymer with a polyester resin oligomer or polymer for the purpose of improving chemical resistance; Good.

  Further, in order to improve the appearance of the molded product and improve the fluidity, the polycarbonate resin may contain a polycarbonate oligomer. The viscosity average molecular weight [Mv] of this polycarbonate oligomer is usually 1500 or more, preferably 2000 or more, and is usually 9500 or less, preferably 9000 or less. Furthermore, the polycarbonate ligomer contained is preferably 30% by mass or less of the polycarbonate resin (including the polycarbonate oligomer).

Further, the polycarbonate resin may be not only a virgin raw material but also a polycarbonate resin regenerated from a used product (so-called material-recycled polycarbonate resin).
However, the regenerated polycarbonate resin is preferably 80% by mass or less of the polycarbonate resin, and more preferably 50% by mass or less. Recycled polycarbonate resin is likely to have undergone deterioration such as heat deterioration and aging deterioration, so when such polycarbonate resin is used more than the above range, hue and mechanical properties can be reduced. It is because there is sex.

[Polyalkylene glycol compound (B)]
The polycarbonate resin composition for thin optical parts of the present invention contains a polyalkylene glycol compound (B) having a number average molecular weight of 500 to 5,000.
The polyalkylene glycol compound (B) is preferably a compound represented by the following general formula (III), for example, a branched polyalkylene glycol compound represented by the following general formula (III-1) or the following general formula ( And a straight-chain polyalkylene glycol compound represented by III-2). As a polyalkylene glycol compound (B), a random copolymer and a block copolymer may be sufficient, and a copolymer with another copolymerization component may be sufficient.

(In formula (III), Q is a linear or branched alkylene group, and X and Y are each independently a hydrogen atom, an aliphatic acyl group having 1 to 23 carbon atoms, or an alkyl group having 1 to 23 carbon atoms. And q represents the number of repetitions.)

(In formula (III-1), R represents an alkyl group having 1 to 3 carbon atoms, and X and Y each independently represent a hydrogen atom, an aliphatic acyl group having 1 to 23 carbon atoms, or 1 to 1 carbon atoms. 23 represents an alkyl group, and n represents an integer of 10 to 400.)

(In formula (III-2), X and Y each independently represent a hydrogen atom, an aliphatic acyl group having 1 to 23 carbon atoms or an alkyl group having 1 to 23 carbon atoms, and m is an integer of 2 to 6) , P represents an integer of 6-100.)

  In the above general formula (III-1), the integer (degree of polymerization) n is preferably 10 to 400, more preferably 15 to 200, and still more preferably 20 to 100. When the degree of polymerization n is less than 10, the amount of gas generated during molding tends to increase, and molding defects due to gas, for example, unfilling, gas burnout, and transfer defects may occur. On the other hand, when the polymerization degree n exceeds 400, the effect of improving the hue of the polycarbonate resin composition may not be sufficiently obtained.

  As the branched polyalkylene glycol compound, in general formula (III-1), polypropylene glycol or X-Y is a hydrogen atom and R is a methyl group or polybutylene glycol which is an ethyl group is preferable, and polybutylene is particularly preferable. Glycol.

  In said general formula (III-2), p (polymerization degree) becomes like this. Preferably it is an integer of 6-100, More preferably, it is 8-90, More preferably, it is 10-80. When the polymerization degree p is less than 6, gas is generated during molding, which is not preferable. On the other hand, when the degree of polymerization p exceeds 100, the compatibility is lowered, which is not preferable.

  As a linear polyalkylene glycol compound, in general formula (III-2), X and Y are hydrogen atoms, m is 2, polyethylene glycol, m is 3, polytrimethylene glycol, and m is 4. Preferred examples include polytetramethylene glycol, polypentamethylene glycol in which m is 5, and polyhexamethylene glycol in which m is 6. More preferred are polytrimethylene glycol, polytetramethylene glycol, esterified products or etherified products thereof. .

  In addition, as the polyalkylene glycol compound (B), even if one or both ends thereof are blocked with a fatty acid or alcohol, there is no effect on the performance expression, and a fatty acid ester or ether can be used in the same manner. Therefore, X and / or Y in the general formulas (III-1) and (III-2) may be an aliphatic acyl group or alkyl group having 1 to 23 carbon atoms.

  The esterified product or etherified product of the polyalkylene glycol does not necessarily need to be entirely esterified or etherified, and is preferably a partially esterified product or an etherified product.

As the fatty acid ester product, either a linear or branched fatty acid ester can be used, and the fatty acid constituting the fatty acid ester may be a saturated fatty acid or an unsaturated fatty acid. Also, those in which some hydrogen atoms are substituted with a substituent such as a hydroxyl group can be used.
The fatty acid constituting the fatty acid ester is a monovalent or divalent fatty acid having 1 to 23 carbon atoms, such as a monovalent saturated fatty acid, specifically formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid. , Enanthic acid, caprylic acid, capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid and monovalent unsaturated fatty acids, specifically, Unsaturated fatty acids such as oleic acid, elaidic acid, linoleic acid, linolenic acid and arachidonic acid, and divalent fatty acids having 10 or more carbon atoms, specifically sebacic acid, undecanedioic acid, dodecanedioic acid, tetradecanedioic acid , Tapsia and decenedioic acid, undecenedioic acid, dodecenedioic acid.
These fatty acids can be used alone or in combination. The fatty acid also includes a fatty acid having one or more hydroxyl groups in the molecule.

  Preferable specific examples of the fatty acid ester of branched polyalkylene glycol include polypropylene glycol stearate in which R is a methyl group, X and Y are aliphatic acyl groups having 18 carbon atoms in general formula (III-1), and R is Examples include a methyl group, polypropylene glycol behenate in which X and Y are aliphatic acyl groups having 22 carbon atoms. Preferable specific examples of fatty acid esters of linear polyalkylene glycol include polyalkylene glycol monopalmitate, polyalkylene glycol dipalmitate, polyalkylene glycol monostearate, polyalkylene glycol distearate, polyalkylene glycol (Monopalmitic acid / monostearic acid) ester, polyalkylene glycol behenate and the like.

  The alkyl group constituting the alkyl ether of the polyalkylene glycol may be either linear or branched, for example, carbon number such as methyl group, ethyl group, propyl group, butyl group, octyl group, lauryl group, stearyl group, etc. Examples of such a polyalkylene glycol compound (B) are preferably alkyl methyl ether, ethyl ether, butyl ether, lauryl ether, stearyl ether and the like of polyalkylene glycol.

The number average molecular weight of the polyalkylene glycol compound (B) is 500 to 5000, preferably 550 or more, more preferably 600 or more, and preferably 4000 or less, more preferably 3000 or less. Exceeding the upper limit of the above range is not preferable because the compatibility is lowered, and if it is lower than the lower limit of the above range, gas is generated during molding, which is not preferable.
In addition, the number average molecular weight of a polyalkylene glycol compound (B) here is the number average molecular weight Mn calculated based on the hydroxyl value measured based on JISK1577.

  The said polyalkylene glycol compound (B) may be used individually by 1 type, or may use 2 or more types together.

  Content of a polyalkylene glycol compound (B) is 0.1-2 mass parts with respect to 100 mass parts of polycarbonate resin (A). Even if the content of the polyalkylene glycol compound (B) is less than 0.1 parts by mass or more than 2 parts by mass, the initial hue of the obtained molded product tends to be inferior. The preferable content of the polyalkylene glycol compound (B) is 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, and preferably 1.8 parts by mass with respect to 100 parts by mass of the polycarbonate resin (A). It is below mass parts.

[Oxetane compound (C)]
The resin composition of the present invention contains an oxetane compound (C). By containing the oxetane compound (C) in combination with the polyalkylene glycol compound (B), the heat discoloration can be further improved.

As the oxetane compound (C), any compound having one or more oxetane groups in the molecule can be used. A monooxetane compound having one oxetane group in the molecule and 2 oxetane groups in the molecule. Any of bi- or higher functional polyoxetane compounds having at least one can be used.
By containing the oxetane compound (C), it is possible to further improve the good hue, the high heat discoloration resistance, and the mold contamination resistance. .

  Preferred examples of the monooxetane compound include compounds represented by the following general formula (Ia), (Ib) or (II).

(Wherein R ¹ represents an alkyl group, R ² represents an alkyl group or a phenyl group, R ³ represents a divalent organic group which may have an aromatic ring, and n represents 0 or 1)

In the general formulas (Ia), (Ib) and (II), R ¹ is an alkyl group, preferably an alkyl group having 1 to 6 carbon atoms, preferably a methyl group or an ethyl group, Particularly preferred is an ethyl group.
R ² is an alkyl group or a phenyl group, preferably an alkyl group having 2 to 10 carbon atoms, and may be a chain alkyl group, a branched alkyl group or an alicyclic alkyl group. Alternatively, it may be a chain or branched alkyl group having an ether bond (ether oxygen atom) in the middle of the alkyl chain. Specific examples of R ² include ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, 3-oxypentyl, cyclohexyl, phenyl Examples include groups. Among them, R ² is preferably a ² -ethylhexyl group, a phenyl group, or a cyclohexyl group.

Specific examples of the compound of the general formula (Ia) include 3-hydroxymethyl-3-methyloxetane, 3-hydroxymethyl-3-ethyloxetane, 3-hydroxymethyl-3-propyloxetane, 3-hydroxymethyl- Preferable examples include 3-normal butyl oxetane and 3-hydroxymethyl-3-propyl oxetane. Of these, 3-hydroxymethyl-3-methyloxetane, 3-hydroxymethyl-3-ethyloxetane, and the like are particularly preferable.
As a specific example of the compound of the general formula (Ib), 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane and the like are particularly preferable.

In the general formula (II), R ³ is a divalent organic group which may have an aromatic ring. Examples thereof include an ethylene group, a propylene group, a butylene group, a neopentylene group, and an n-pentamethylene group. , A linear or branched alkylene group having 1 to 12 carbon atoms such as an n-hexamethylene group, a phenylene group, a formula: —CH ² —Ph—CH ² — or —CH ² —Ph—Ph—CH ² — (Where Ph represents a phenyl group), hydrogenated bisphenol A residue, hydrogenated bisphenol F residue, hydrogenated bisphenol Z residue, cyclohexanedimethanol residue, tricyclodeoxy Candimethanol residues and the like can be mentioned.
Specific examples of the compound of the general formula (II) 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-ethyloxetane-3- Yl) methoxy] methyl} oxetane, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene and the like. Particularly preferred examples are listed.

  The oxetane compound (C) may be used alone or in combination of two or more.

  Content of an oxetane compound (C) is 0.001-0.2 mass part with respect to 100 mass parts of polycarbonate resin (A), Preferably it is 0.003 mass part or more, More preferably, it is 0.005 mass. Part or more, more preferably 0.008 part by weight or more, preferably 0.18 part by weight or less, more preferably 0.17 part by weight or less, and further preferably 0.16 part by weight or less. When the content of the oxetane compound (C) is less than 0.001 part by mass, the hue and the heat discoloration tend to be insufficient, and when it exceeds 0.2 part by mass, the heat discoloration tends to deteriorate instead, Gas generation during molding, hue and wet heat stability are also likely to decrease.

[Phosphorus stabilizer (D)]
The polycarbonate resin composition of the present invention preferably contains a phosphorus stabilizer. By containing a phosphorus stabilizer, the hue of the polycarbonate resin composition of the present invention becomes better, and the heat discoloration is further improved.
Any known phosphorous stabilizer can be used. Specific examples include phosphorus oxo acids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; acidic pyrophosphate metal salts such as acidic sodium pyrophosphate, acidic potassium pyrophosphate, and acidic calcium pyrophosphate; phosphoric acid Phosphates of Group 1 or Group 2B metals such as potassium, sodium phosphate, cesium phosphate, and zinc phosphate; phosphate compounds, phosphite compounds, phosphonite compounds and the like are mentioned, and phosphite compounds are particularly preferred. By selecting a phosphite compound, a polycarbonate resin composition having higher discoloration resistance and continuous productivity can be obtained.

Here, the phosphite compound is a trivalent phosphorus compound represented by the general formula: P (OR) ₃ , and R represents a monovalent or divalent organic group.
Examples of such phosphite compounds include triphenyl phosphite, tris (monononylphenyl) phosphite, tris (monononyl / dinonyl phenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphine. Phyto, monooctyl diphenyl phosphite, dioctyl monophenyl phosphite, monodecyl diphenyl phosphite, didecyl monophenyl 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-methylene (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] -dioxaphosphine.

  Among these phosphite compounds, the aromatic phosphite compound represented by the following formula (1) or (2) is more preferable because the heat discoloration of the polycarbonate resin composition of the present invention is effectively enhanced. .

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

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

  As the phosphite compound represented by the above formula (1), triphenyl phosphite, tris (monononylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, etc. are preferable, Of these, tris (2,4-di-tert-butylphenyl) phosphite is more preferable. Specific examples of such organic phosphite compounds include, for example, “ADEKA STAB 1178” manufactured by ADEKA, “SUMILIZER TNP” manufactured by Sumitomo Chemical Co., Ltd., “JP-351” manufactured by Johoku Chemical Industry Co., Ltd., “ADEKA STAB manufactured by ADEKA 2112 "," Irgaphos 168 "manufactured by BASF," JP-650 "manufactured by Johoku Chemical Industry Co., Ltd., and the like.

  Examples of the phosphite compound represented by the above formula (2) include bis (2,4-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite and bis (2,6-di-tert- Those having a pentaerythritol diphosphite structure such as butyl-4-methylphenyl) pentaerythritol diphosphite and bis (2,4-dicumylphenyl) pentaerythritol diphosphite are particularly preferred. Specific examples of such an organic phosphite compound include “Adeka Stub PEP-36”, “Adeka Stub PEP-24G” manufactured by Adeka, “Doverphos S-9228” manufactured by Doverchemical, and the like.

Among the phosphite compounds, the aromatic phosphite compound represented by the above formula (2) is more preferable because the hue is more excellent.
In addition, 1 type may contain phosphorus stabilizer and 2 or more types may contain it by arbitrary combinations and a ratio.

  The content of the phosphorus stabilizer (D) is preferably 0.005 to 0.5 parts by mass, more preferably 0.007 parts by mass or more, further preferably 100 parts by mass of the polycarbonate resin (A). Is 0.008 parts by mass or more, particularly preferably 0.01 parts by mass or more, more preferably 0.4 parts by mass or less, still more preferably 0.3 parts by mass or less, particularly preferably 0.2 parts by mass or less. Most preferably, it is 0.1 parts by mass or less. When the content of the phosphorus stabilizer (D) is less than 0.005 parts by mass of the above range, the hue and heat discoloration are insufficient, and the content of the phosphorus stabilizer (D) is 0.5 parts by mass. If it exceeds 1, not only the heat discoloration is deteriorated, but also the wet heat stability is lowered.

[Additives, etc.]
The polycarbonate resin composition of the present invention includes other additives other than those described above, for example, antioxidants, mold release agents, ultraviolet absorbers, fluorescent brighteners, pigments, dyes, other polymers other than polycarbonate resins, Additives such as a flame retardant, an impact resistance improver, an antistatic agent, a plasticizer, and a compatibilizing agent can be contained. These additives may be used alone or in combination of two or more.

[Production Method of Polycarbonate Resin Composition]
There is no restriction | limiting in the manufacturing method of the polycarbonate resin composition of this invention, The manufacturing method of a well-known polycarbonate resin composition can be employ | adopted widely, a polycarbonate resin (A), a polyalkylene glycol compound (B), an oxetane compound (C), and The other components to be blended as necessary are mixed in advance using various mixers such as a tumbler and a Henschel mixer, for example, then a Banbury mixer, a roll, a brabender, a single screw kneading extruder, a twin screw kneading extruder, The method of melt-kneading with mixers, such as a kneader, is mentioned. The temperature for melt kneading is not particularly limited, but is usually in the range of 240 to 320 ° C.

[Optical member]
The polycarbonate resin composition for an optical member of the present invention can be produced by molding pellets obtained by pelletizing the above polycarbonate resin composition by various molding methods. Moreover, the resin melt-kneaded by an extruder can be directly molded into an optical member without going through the pellets.

The polycarbonate resin composition of the present invention has a good hue and a high degree of heat discoloration and has very little mold contamination at the time of molding. It is suitably used for forming an easily thin optical member.
In particular, in the case of a thin molded product such as a light guide plate for a liquid crystal backlight, the resin temperature during injection molding is generally higher than 260 to 300 ° C., which is a temperature applied to polycarbonate resin injection molding. The resin temperature is preferably 305 to 380 ° C. The resin temperature is more preferably 310 ° C or higher, further preferably 315 ° C or higher, particularly preferably 320 ° C or higher, and more preferably 370 ° C or lower. When the conventional polycarbonate resin composition is used, there is a problem that when the resin temperature at the time of molding is increased in order to mold a thin molded product, the molded product is likely to be yellowed. By using the composition, it becomes possible to produce a molded product having a good hue, particularly a thin optical member, even in the above temperature range.
The resin temperature is grasped as the barrel set temperature when it is difficult to directly measure the resin temperature.

  Here, the thin-walled molded article refers to a molded article having a plate-like portion having a thickness of usually 3 mm or less, preferably 2 mm or less, preferably 1 mm or less, more preferably 0.8 mm or less. Here, the plate-like portion may be a flat plate or a curved plate, may be a flat surface, may have irregularities on the surface, and the cross section has an inclined surface. Or a wedge-shaped cross section.

Examples of the optical member include parts of equipment and instruments that directly or indirectly use a light source such as an LED, an organic EL, an incandescent bulb, a fluorescent lamp, and a cathode tube. Typical examples include a light guide plate and a surface light emitter member. It is illustrated as a thing.
The light guide plate is used to guide light from a light source such as an LED in a liquid crystal backlight unit, various display devices, and lighting devices. It diffuses by the unevenness and emits uniform light. The shape is usually flat, and the surface may or may not have irregularities.
The light guide plate is usually formed preferably by an injection molding method, an ultra-high speed injection molding method, an injection compression molding method, or the like.

  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 mobile phones, mobile notebooks, netbooks, slate PCs, tablet PCs, smartphones, tablet terminals, and other portable terminals, cameras, watches, notebook computers, various displays, lighting devices, and the like. It is done.

  Further, as an optical member, a light guide or a lens that guides light from a light source such as an LED in a vehicle headlamp (head lamp) or a rear lamp, a fog lamp, etc. for an automobile or a motorcycle is also suitable. Also, it can be suitably used.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not construed as being limited to the following examples.
The raw materials and evaluation methods used in the following examples and comparative examples are as follows.

(Examples 1-11, Comparative Examples 1-4)
[Production of resin composition pellets]
Each component described above was blended in the proportions (parts by mass) shown in Tables 2 to 3 below, mixed for 20 minutes with a tumbler, and then a single-screw extruder with a screw having a screw diameter of 40 mm (manufactured by Tanabe Plastic Machinery Co., Ltd.). VS-40 ") was melt-kneaded at a cylinder temperature of 240 ° C, and pellets were obtained by strand cutting.

[Evaluation of Hue (YI)]
The obtained pellets were dried at 120 ° C. for 5 to 7 hours with a hot air circulating dryer, and then with an injection molding machine (“EC100SX-2A” manufactured by Toshiba Machine Co., Ltd.) at a resin temperature of 340 ° C. and a mold temperature of 80 ° C. A long optical path molded product (300 mm × 7 mm × 4 mm) was molded.
About this long optical path molded product, YI (yellowing degree) was measured at an optical path length of 300 mm. For the measurement, a long optical path spectral transmission color meter (“ASA 1” manufactured by Nippon Denshoku Industries Co., Ltd., C light source, 2 ° visual field) was used.
Further, this long optical path molded product was subjected to heat treatment at 95 ° C. for 500 hours, and then the same evaluation as described above was performed.

[Evaluation of mold contamination (mold deposit)]
Contamination evaluation in injection molding (mold dirt)
After the pellets obtained above were dried at 120 ° C. for 5 hours, an injection molding machine (“MINIMAT M8 / 7A” manufactured by Sumitomo Heavy Industries, Ltd.) was used, and a drop mold as shown in FIG. 1 was used. Then, under the conditions of a cylinder temperature of 340 ° C., a molding cycle of 10 seconds, and a mold temperature of 40 ° C., 500 shot injection molding was performed, and the state of dirt due to white deposits generated on the metal mirror surface on the mold fixing side after completion was The following criteria compared with Comparative Example 4 were evaluated and judged visually.
(Double-circle): The mold deposit is extremely less than the state after 500 shot molding in Comparative Example 4, and the mold contamination resistance is very good.
◯: There are fewer mold deposits than the state after 500 shot molding in Comparative Example 4, and the mold contamination resistance is good.
Δ: Die deposits are less than the state after 500 shot molding of Comparative Example 4, but some mold resistance is observed.
X: Mold adhering material is at the same level as that after 500 shot molding in Comparative Example 4, and the mold contamination is noticeable.

The drop mold shown in FIG. 1 is a mold designed to introduce a resin composition from the gate G so that the generated gas easily accumulates at the tip P portion. The gate G has a width of 1 mm and a thickness of 1 mm. In FIG. 1, the width h1 is 14.5 mm, the length h2 is 7 mm, the length h3 is 27 mm, and the thickness of the molded part is 3 mm.
The above evaluation results are shown in Tables 2 to 3 below.

  The polycarbonate resin composition of the present invention has a good hue, has very little mold contamination, and does not cause white turbidity or a decrease in transmittance. Very expensive.

Claims (6)

  0.1-2 parts by mass of polyalkylene glycol compound (B) having a number average molecular weight of 500-5000 and 0.001-0.2 parts by mass of oxetane compound (C) with respect to 100 parts by mass of polycarbonate resin (A). A polycarbonate resin composition for optical members, comprising: The polycarbonate resin composition for an optical member according to claim 1, wherein the oxetane compound (C) is a compound represented by the following general formula (Ia), (Ib) or (II).
(Wherein R ¹ represents an alkyl group, R ² represents an alkyl group or a phenyl group, R ³ represents a divalent organic group which may have an aromatic ring, and n represents 0 or 1)   The polycarbonate resin composition for an optical member according to claim 1 or 2, wherein the oxetane function in the oxetane compound (C) is bifunctional or higher.   The optical member according to any one of claims 1 to 3, wherein the mass ratio (C) / (B) of the content of the oxetane compound (C) and the polyalkylene glycol compound (B) is 0.005 to 0.2. Polycarbonate resin composition.   A light guide plate comprising the polycarbonate resin composition according to claim 1.   The light guide member for vehicle lamps which consists of a polycarbonate resin composition in any one of Claims 1-4.