JP6396792B2 - Polycarbonate resin composition for light guide member and light guide member - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a polycarbonate resin composition for a light guide member and a light guide member, and more specifically, a polycarbonate resin composition for a light guide member having good fluidity and hue and having no problem of mold deposits, and molding the same. It is related with the light guide member which consists of.

  A surface light source device is incorporated in a liquid crystal display device used for a personal computer, a cellular phone and the like in order to meet demands for thinning, lightening, labor saving, and high definition. The surface light source device has a wedge-shaped cross-section light guide plate or a flat plate shape with a uniform inclined surface for the purpose of uniformly and efficiently guiding incident light to the liquid crystal display side. A light guide plate is provided. In some cases, an uneven pattern is formed on the surface of the light guide plate to provide a light scattering function.

  Such a light guide plate is obtained by injection molding of a thermoplastic resin, and the above concavo-convex pattern is imparted by transferring a concavo-convex portion formed on the surface of the nest. Conventionally, the light guide plate has been molded from a resin material such as polymethylmethacrylate (PMMA). Recently, however, a display device that displays a clearer image has been demanded, and the temperature inside the device is increased by heat generated near the light source. Therefore, it is being replaced with a polycarbonate resin material having higher heat resistance.

  Polycarbonate resin has excellent mechanical properties, thermal properties, electrical properties, and weather resistance, but its light transmittance is lower than that of PMMA, etc., so a surface light source body is composed of a light guide plate made of polycarbonate resin and a light source. In this case, there is a problem that the luminance is low. Recently, it has been demanded to reduce the difference in chromaticity between the light incident portion of the light guide plate and a location away from the light incident portion, but there is a problem that the polycarbonate resin is more easily yellowed than the PMMA resin.

Patent Document 1 describes a method for improving light transmittance and luminance by adding an acrylic resin and an alicyclic epoxy. Patent Document 2 describes a method for modifying the end of the polycarbonate resin to transfer the uneven portion to the light guide plate. A method for improving the brightness by increasing the brightness, and Patent Document 3 propose a method for improving the brightness by introducing a copolyester carbonate having an aliphatic segment to improve the transferability.
However, although the method of Patent Document 1 improves the hue by adding an acrylic resin, the light transmittance and luminance cannot be increased due to white turbidity, and the transmittance is improved by adding an alicyclic epoxy. Although there is a possibility, the effect of improving the hue is not recognized. In the case of the methods of Patent Document 2 and Patent Document 3, although improvement of fluidity and transferability can be expected, there is a drawback that heat resistance is lowered.

  On the other hand, it is known to blend polyethylene glycol or poly (2-methyl) ethylene glycol or the like into a thermoplastic resin such as a polycarbonate resin, and Patent Document 4 discloses a γ-ray radiation resistant polycarbonate resin containing the same. Patent Document 5 describes a thermoplastic resin composition excellent in antistatic property and surface appearance, which is blended with PMMA or the like.

  However, especially in various portable terminals such as recent smartphones and tablet terminals, thinning, large thinning, and high performance are progressing at a remarkable speed. There is a demand for a light guide member material having a high level of fluidity (moldability) and excellent color tone.

  And when molding the polycarbonate resin composition for light guide members aiming at such high performance, generation | occurrence | production of metal mold | die adhesion | attachment has become a big problem. Since mold deposits have a great influence on the transfer of the concavo-convex optical pattern such as the light guide plate, frequent cleaning maintenance of the mold is forced particularly when molding a high performance light guide member.

JP-A-11-158364 JP 2001-208917 A JP 2001-215336 A JP-A-1-22959 JP-A-9-227785

  An object of the present invention is to provide a polycarbonate resin composition for a light guide member that has good fluidity and hue and has no problem of mold deposits.

As a result of repeated examination and analysis on the cause and mechanism of such mold adhesion, the present inventor found that the mold adhesion was caused by a gas generated by heating during molding, and that the gas generation was caused by the viscosity average molecular weight. 15,000 to 20,000 polycarbonate resin (a1) and a viscosity average molecular weight of 10,000 to 14,500 polycarbonate resin (a2) are mixed in a combination in which the molecular weight difference between them is 4,000 or more. Thus, it was found that the adhesion of the mold was remarkably reduced and the polycarbonate resin composition further combined with the polyalkylene glycol was found to be excellent in fluidity and hue, and the present invention was completed.
The present invention is as follows.

[1] 40 to 90% by mass of a polycarbonate resin (a1) having a viscosity average molecular weight of 15,000 to 20,000 and 10 to 60% by mass of a polycarbonate resin (a2) having a viscosity average molecular weight of 10,000 to 14,500 And 0.1 to 2 parts by mass of the polyalkylene glycol (B) with respect to 100 parts by mass of the polycarbonate resin (A). The viscosity average of the polycarbonate resin (a1) and the polycarbonate resin (a2) A polycarbonate resin composition for a light guide member, wherein the difference in molecular weight is 4,000 or more.
[2] The polycarbonate resin composition for a light guide member according to the above [1], wherein the heat generation amount of the component represented by the following general formula (1) is 400 μg / g or less.
(In the formula, n is 0 or 1.)
[3] The polycarbonate resin composition for a light guide member according to the above [1] or [2], wherein the polycarbonate resin composition does not contain 0.01% by mass or more of glycerin monoester.
[4] A light guide member formed by molding the polycarbonate resin composition according to any one of [1] to [3].

  Since the polycarbonate resin composition of the present invention is a polycarbonate resin material for a light guide member that has good fluidity and hue and has no problem of occurrence of mold deposits, it is particularly suitable for a light guide member typified by a light guide plate. It can be preferably used.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples.
In addition, in this-application specification, unless there is particular notice, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

[Overview]
The polycarbonate resin composition for a light guide member of the present invention has a viscosity average molecular weight of 15,000 to 20,000 polycarbonate resin (a1) 40 to 90% by mass and a viscosity average molecular weight of 10,000 to 14,500. The polycarbonate resin (a1) is composed of 10 to 60% by mass, and the polycarbonate resin (A) is contained in an amount of 0.1 to 2 parts by mass with respect to 100 parts by mass of the polycarbonate resin (A). ) And the polycarbonate resin (a2) have a difference in viscosity average molecular weight of 4,000 or more.
Hereinafter, each component, light guide member and the like constituting the polycarbonate resin composition of the present invention will be described in detail.

[Polycarbonate resin (A)]
The polycarbonate resin (A) which is the component (A) of the present invention contains the above-described polycarbonate resin (a1) and polycarbonate resin (a2).
The viscosity average molecular weight (Mv) of the polycarbonate resin (a1) is in the range of 15,000 to 20,000. If Mv is less than 15,000, low molecular weight components increase and the amount of gas generation increases. If it exceeds 20,000, the hue deteriorates. The Mv of the polycarbonate resin (a1) is preferably 15,500 or more, and preferably 19,500 or less.
The viscosity average molecular weight (Mv) of the polycarbonate resin (a2) is in the range of 10,000 to 14,500. If Mv is less than 10,000, low molecular weight components increase and the amount of gas generated increases. If it exceeds 14,500, the hue deteriorates. Mv of the polycarbonate resin (a2) is preferably 10,500 or more, and preferably 14,000 or less.

  The difference in Mv between the polycarbonate resin (a1) and the polycarbonate resin (a2) needs to be 4,000 or more. When the Mv of the polycarbonate resin (a2) is 4,000 or more smaller than the Mv of the polycarbonate resin (a2), low molecular weight components increase and the amount of gas generated increases. The difference in Mv is preferably 4,500 or more, more preferably 5,000 or more.

The viscosity average molecular weight Mv was determined 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. It means a value calculated from 1.23 × 10 ⁻⁴ Mv ^0.83 . The intrinsic viscosity [η] is a value calculated by the following equation by measuring the specific viscosity [η _sp ] at each solution concentration [C] (g / dl).

  There are no restrictions on the types of the polycarbonate resins (a1) and (a2), and the polycarbonate resins (a1) and (a2) may each be used alone, or two or more types in any combination and in any ratio. You may use together.

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 the carbon directly bonded to the carbonic acid bond is an aromatic carbon and an aliphatic polycarbonate resin in which the carbon is an aliphatic carbon, respectively, as polycarbonate resins (a1) and (a2). Any of these can be used. Of these, aromatic polycarbonate resins are preferred from the viewpoints of heat resistance, mechanical properties, electrical characteristics, and the like.

  Examples of the polycarbonate resins (a1) and (a2) include polycarbonate polymers obtained by reacting a dihydroxy compound and a carbonate precursor. 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,
1,1-bis (4-hydroxyphenyl) hexane,
2,2-bis (4-hydroxyphenyl) hexane,
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 (a1) and (a2) The manufacturing method of polycarbonate resin (a1) and (a2) 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, the case where a polycarbonate resin is manufactured by the 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).

-Melt transesterification method Next, the case where polycarbonate resin is manufactured by the melt transesterification method is demonstrated.
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 is used. 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. When performing by a batch type, the order which mixes a reaction substrate, a reaction medium, a catalyst, an additive, etc. is arbitrary as long as a desired aromatic polycarbonate resin is obtained, What is necessary is just to set an appropriate order 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 terminal hydroxyl group concentrations of the polycarbonate resins (a1) and (a2) are arbitrary and may be appropriately selected and determined, but are 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.

[Polyalkylene glycol (B)]
The polycarbonate resin composition for a light guide member of the present invention contains a polyalkylene glycol (B).
The polyalkylene glycol (B) is an ether polymer composed of units derived from alkylene glycol, and the alkylene group may be a linear alkylene group or a branched alkylene group.

  The polyalkylene glycol (B) is preferably a polymer composed of units derived from an alkylene glycol having 2 to 6 carbon atoms. Examples of the alkylene glycol include ethylene glycol, propylene glycol, and butylene glycol. Pentylene glycol, hexylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, neopentyl glycol, 3-methyltetramethylene glycol, hexamethylene glycol, etc., and more preferable are alkylene glycols having 3 to 6 carbon atoms. Propylene glycol, butylene glycol, trimethylene glycol, and tetramethylene glycol are particularly preferable.

  The polyalkylene glycol (B) may be a single alkylene glycol homopolymer or a random copolymer or block copolymer of two or more alkylene glycols.

  Specific examples of the polyalkylene glycol (B) include polyethylene glycol, polypropylene glycol, polybutylene glycol, polypentylene glycol, polyhexylene glycol, polytrimethylene glycol, polytetramethylene glycol, polypentamethylene glycol, Polyhexamethylene glycol and the like are preferable, and among them, polypropylene glycol, polybutylene glycol, polytrimethylene glycol, and polytetramethylene glycol are preferable.

  The polyalkylene glycol (B) has no influence on the performance even if one or both ends thereof are sealed with alkyl ether, aryl ether, aralkyl ether, fatty acid ester, aryl ester, etc. Esterified products can be used as well.

  As the alkyl group constituting the alkyl ether, either linear or branched can be used, and an alkyl group having 1 to 22 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, an octyl group, a lauryl group, Preferred examples include stearyl groups such as polyalkylene glycol methyl ether, ethyl ether, butyl ether, lauryl ether, and stearyl ether.

  The aryl group constituting the aryl ether is preferably an aryl group having 6 to 22 carbon atoms, more preferably 6 to 12 carbon atoms, still more preferably 6 to 10 carbon atoms, such as a phenyl group, a tolyl group, or a naphthyl group. And a phenyl group, a tolyl group and the like are preferable. The aralkyl group is preferably an aralkyl group having 7 to 23 carbon atoms, more preferably 7 to 13 carbon atoms, still more preferably 7 to 11 carbon atoms, and examples thereof include a benzyl group and a phenethyl group. Particularly preferred.

The fatty acid constituting the fatty acid ester may be either linear or branched, and may be a saturated fatty acid or an unsaturated fatty acid.
The fatty acid constituting the fatty acid ester is a monovalent or divalent fatty acid having 1 to 22 carbon atoms, such as a monovalent saturated fatty acid, such as 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 monounsaturated fatty acids such as oleic acid, elaidic acid, Unsaturated fatty acids such as linoleic acid, linolenic acid, and arachidonic acid, and divalent fatty acids having 10 or more carbon atoms such as sebacic acid, undecanedioic acid, dodecanedioic acid, tetradecanedioic acid, tapsiaic acid and decenedioic acid, undecene Diacid, dodecenedioic acid.

  The aryl group constituting the aryl ester is preferably an aryl group having 6 to 22 carbon atoms, more preferably 6 to 12 carbon atoms, and still more preferably 6 to 10 carbon atoms, such as a phenyl group, a tolyl group, or a naphthyl group. And a phenyl group, a tolyl group and the like are preferable. Since the end-capping group exhibits good compatibility with polycarbonate even if it is an aralkyl group, it can exhibit the same action as an aryl group. The aralkyl group preferably has 7 to 23 carbon atoms, more preferably Aralkyl groups having 7 to 13 carbon atoms, more preferably 7 to 11 carbon atoms are preferable, and examples thereof include benzyl group and phenethyl group, and benzyl group is particularly preferable.

The number average molecular weight of the polyalkylene glycol (B) is preferably 700 or more, more preferably 800 or more, preferably 4,000 or less, more preferably 3,000 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.
The number average molecular weight of the polyalkylene glycol compound is a number average molecular weight calculated based on the hydroxyl value measured in accordance with JIS K1577.

  Content of polyalkylene glycol (B) is 0.1-2 mass parts with respect to 100 mass parts of polycarbonate resin (A). The preferred content is 0.15 parts by mass or more, more preferably 0.2 parts by mass or more, preferably 1.9 parts by mass or less, more preferably 1.7 parts by mass or less, and further preferably 1.6 parts by mass. It is as follows. When the content is less than 0.1 parts by mass, the improvement in hue and yellowing is not sufficient, and the effect of reducing gas generation becomes insufficient. When the amount exceeds 2 parts by mass, the transmittance decreases due to white turbidity of the polycarbonate resin, and the amount of mold deposits due to the gas derived from polyalkylene glycol increases.

[Additives, etc.]
The polycarbonate resin composition of the present invention has other additives other than those described above, for example, stabilizers, antioxidants, ultraviolet absorbers, fluorescent brighteners, pigments, dyes, as long as the effects of the present invention are not significantly impaired. In addition to the polycarbonate resin, additives such as a polymer, a flame retardant, an impact resistance improver, an antistatic agent, a plasticizer, and a compatibilizer can be contained. These additives may be used alone or in combination of two or more.

Examples of the release agent include various known release agents such as aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15000, and polysiloxane silicone oil. Can be mentioned.
However, among these, it is preferable not to contain an ester of an aliphatic carboxylic acid and an alcohol, especially glycerin monoester, and even if it is contained, the content thereof should not be 0.01% by mass or more in the polycarbonate resin composition. Is preferred. When the content of glycerin monoester is 0.01% by mass or more, the amount of deposits on the mold increases, which is not preferable.

[Phosphorus stabilizer]
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 oxoacids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, 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 such phosphite compounds, an aromatic phosphite compound represented by the following formula (2) or (3) is more preferable because the heat discoloration of the polycarbonate resin composition of the present invention is effectively enhanced. .

[In Formula (2), 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 (3), 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 (2), 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., and “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 (3) 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 organic phosphite compounds include “ADEKA STAB PEP-24G”, “ADEKA STAB PEP-36” manufactured by ADEKA, “Doverphos S-9228” manufactured by Doverchemical, and the like.

  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 is preferably 0.005 to 0.5 parts by mass, more preferably 0.007 parts by mass or more, and still more preferably 0.008 with respect to 100 parts by mass of the polycarbonate resin (A). Part by mass or more, particularly preferably 0.01 part by mass or more, more preferably 0.4 part by mass or less, further preferably 0.3 part by mass or less, especially 0.2 part by mass or less, especially 0.1 The mass part or less is preferable. When the content of the phosphorus stabilizer is less than 0.005 parts by mass of the above range, the hue and heat discoloration tend to be insufficient, and when it exceeds 0.5 parts by mass, the heat discoloration tends to deteriorate. Also, wet heat stability tends to decrease.

[Production Method of Polycarbonate Resin Composition]
There is no limitation on the production method of the polycarbonate resin composition of the present invention, and a wide variety of production methods of known polycarbonate resin compositions can be adopted. Polycarbonate resins (a1), (a2) and polyalkylene glycol (B), and as necessary Other ingredients to be blended in accordance with, for example, various mixers such as a tumbler and Henschel mixer, after pre-mixing, such as Banbury mixer, roll, Brabender, single-screw kneading extruder, twin-screw kneading extruder, kneader The method of melt-kneading with a mixer is mentioned. The temperature for melt kneading is not particularly limited, but is usually in the range of 240 to 320 ° C.

The polycarbonate resin composition of the present invention is preferably characterized in that the heat generation amount of the component represented by the following general formula (1) is 400 μg / g or less.
(In the formula, n is 0 or 1.)

  The component represented by the general formula (1) is one of the components found as a heat generation gas component at the time of molding by the analysis of the present inventor, but the polycarbonate resin composition of the present invention is a polycarbonate resin ( In addition to the fact that the content of this component is reduced by the combination of a1) and (a2), the addition of polyalkylene glycol (B) synergistically reduces the amount of heat generated by this component. It is considered that this contributes to the manifestation of the effects of the present invention.

  The content of the component represented by the general formula (1) is more preferably 300 μg / g or less, further preferably 250 μg / g or less, particularly preferably 200 μg / g or less, and the lower limit of the content is preferably 10 μg. / G or more.

  In addition, the measuring method of the heat generation amount of the component shown by General formula (1) is as having explained in full detail in the Example.

  The polycarbonate resin composition for a light guide member of the present invention can produce a light guide member 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 formed into a light guide member without going through the pellets.

  The polycarbonate resin composition of the present invention is excellent in fluidity, and even when formed into a thin molded product, it has an excellent appearance of a molded product free of white spot foreign matter, has good hue and heat discoloration, and has no problem of mold adhesion. Therefore, it is suitably used for forming a thin light guide member, particularly by an injection molding method. The resin temperature at the time of injection molding is preferably molded at a resin temperature higher than 260 to 300 ° C., which is a temperature generally applied to injection molding of polycarbonate resin, and a resin temperature of 305 to 380 ° C. is preferable. 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. 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 product refers to a molded product having a plate-shaped portion having a thickness of usually 1 mm or less, preferably 0.8 mm or less, more preferably 0.6 mm or less. Here, the plate-like portion may be 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 light guide 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 molded using the resin composition of the present invention exhibits a very good hue and is excellent in heat discoloration.

  The light guide plate made of 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.

  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 used in the following Examples and Comparative Examples are as shown in Table 1 below.
The measurement of the viscosity average molecular weight Mv of the polycarbonate resin is as described above.

(Examples 1-6, 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 and 3 below, mixed for 20 minutes with a tumbler, and then a single screw extruder with a vent with 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.

[Measurement of heat generation gas component and generation amount]
10 mg of the resin composition was weighed and placed in a quartz glass sample tube, and heat treatment was performed at 340 ° C. for 10 minutes under a helium stream (60 ml / min) using a TD-20 manufactured by Shimadzu Corporation. Cooled and collected at -10 ° C. This was heated and desorbed at 340 ° C., and a GC / MS analyzer (separation column: UA-5 manufactured by Frontier Laboratories) consisting of GC-2010Plus and GCMS-QP2010Ultra manufactured by Shimadzu Corporation was used under a helium gas flow (3 ml). / Min) under the condition of 10 ° C./min, the temperature was raised from 50 ° C. to 380 ° C., and the amount of the generated gas component (decane converted amount per gram of resin composition μg [μg / g]) was measured. The heating generation amount of the component represented by the general formula (1) was measured.

[Evaluation of mold deposits]
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 (“SE7M” manufactured by Sumitomo Heavy Industries, Ltd.) at a resin temperature of 340 ° C. and a mold temperature of 60 ° C. A drop mold product (27 mm × 15 mm × 3 mm) was molded. After molding this 350 shots, the mold surface was visually observed, and the amount of mold deposits was ranked in five stages.
The rank of the mold deposits is 1: almost not present 2: slightly adhered deposits are observed 3: adhered deposits are observed 4: many adhered deposits are observed 5: very much adhered deposits are observed

[Measurement of hue (YI) and light transmittance]
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.
The above evaluation results are shown in Table 2 and Table 3 below.

  Since the polycarbonate resin composition of the present invention is a polycarbonate resin material that has good fluidity and hue and does not have a problem of adhesion to the mold, it can be used very suitably for various light guide members, and has very high industrial applicability. Very expensive.

Claims (3)

From 40 to 90% by mass of the polycarbonate resin (a1) having a viscosity average molecular weight of 15,000 to 20,000 and from 10 to 60% by mass of the polycarbonate resin (a2) having a viscosity average molecular weight of 10,000 to 14,500. The polyalkylene glycol (B) is contained in an amount of 0.1 to 2 parts by mass with respect to 100 parts by mass of the polycarbonate resin (A), and the difference in viscosity average molecular weight between the polycarbonate resin (a1) and the polycarbonate resin (a2) There Ri der 4,000, guide member polycarbonate resin composition glycerin monoester is characterized in that it does not contain more than 0.01 mass%. The polycarbonate resin composition for a light guide member according to claim 1, wherein the heat generation amount of the component represented by the following general formula (1) is 400 μg / g or less.
(In the formula, n is 0 or 1.) Claim 1 or 2 light guide member obtained by molding the polycarbonate resin composition according to.