WO2015011994A1

WO2015011994A1 - Polycarbonate resin composition for thin optical component, and thin optical component

Info

Publication number: WO2015011994A1
Application number: PCT/JP2014/064717
Authority: WO
Inventors: 恵介冨田; 松本　晋
Original assignee: 三菱エンジニアリングプラスチックス株式会社
Priority date: 2013-07-26
Filing date: 2014-06-03
Publication date: 2015-01-29

Abstract

Provided are a polycarbonate resin composition for a thin optical component, and a thin optical component, which have high transmittance, good hue, and exceptional resistance to thermal discoloration. [Solution] The polycarbonate resin composition for thin optical component is characterized by containing, with respect to 100 mass parts of a polycarbonate resin (A), 0.1-2 mass parts of a polyalkylene ether glycol compound (B) represented by the following formula (1), and 0.005-0.5 mass parts of a phosphorus based stabilizer.

Description

Polycarbonate resin composition for thin optical parts and thin optical parts

The present invention relates to a polycarbonate resin composition for thin optical parts and a thin optical part, and more specifically, a polycarbonate resin composition for thin optical parts having high transmittance and good hue, a thin optical part formed by molding the same, and a thin optical part The present invention relates to a method for manufacturing an optical component, a polycarbonate resin pellet for a thin optical component, and a method for manufacturing a polycarbonate resin pellet for a thin optical component.

2. Description of the Related Art A liquid crystal display device used in personal computers, mobile phones, and the like has a surface light source device incorporated in order to meet the 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 the 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 is excellent in mechanical properties, thermal properties, electrical properties, and weather resistance, but its light transmittance is lower than that of PMMA, etc., so that a surface light source body is formed from a light guide plate made of polycarbonate resin and a light source. When configured, 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 ether glycol or poly (2-methyl) ethylene ether glycol or the like into a thermoplastic resin such as a polycarbonate resin. Patent Document 4 discloses a γ-irradiation-resistant polycarbonate containing the same. Patent Document 5 describes a thermoplastic resin composition excellent in antistatic property and surface appearance in which the resin is blended with PMMA or the like.
In Patent Document 6, polyethylene ether glycol represented by the formula: X—O— [CH (—R) —CH ₂ —O] n—Y (R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms) or There have been proposals for improving transmittance and hue by blending poly (2-alkyl) ethylene ether glycol. By adding polyethylene ether glycol or poly (2-alkyl) ethylene ether glycol, the transmittance and yellowing degree (yellow index: YI) are slightly improved.

However, in recent years, especially in various portable terminals such as smartphones and tablet terminals, thinning and large-sized thinning are proceeding at a remarkable speed, and the edge type in which light is incident on the light guide plate from the direct edge type to the side edge. Has been adopted, and sufficient luminance as an ultra-thin light source has been required. In such a high-end light guide plate, at present, the required specifications are not satisfied at the transmittance and YI level achieved by the above-described conventional technology.

In addition, the polycarbonate resin for the light guide is thin-molded at a temperature higher than the molding temperature of normal polycarbonate resin, so even if the mechanical strength is sacrificed, the viscosity average molecular weight is lowered and the fluidity is increased. Is required. Thus, the polycarbonate resin for thin optical components typified by the light guide is a material having a low mechanical strength compared to the conventional polycarbonate resin, so when producing pellets with an extruder, The extruded polycarbonate resin strands are easily broken during cooling, and there is a problem that stable production is difficult.
Moreover, even if the pellets manufactured in the factory are simply put into a paper bag or a flexible container for delivery and transported, a part thereof is pulverized by contact between the pellets. When a light guide or the like is molded using such a pellet mixed with fine powder, there is a problem that yellowing of the molded product or optical fluctuation is likely to occur.
As a means to solve the problem caused by fine powder, it can be solved by removing the fine powder through a fine powder remover when molding, but there is a possibility of extra steps entering and contamination, so if possible There is a request that there is no.

In Patent Document 7, in order to prevent the occurrence of silver streak in an optical disc, the average length of the pellets is in the range of 2.5 to 3.5 mm, and more than 70% of the average length length is plus or minus 0. A polycarbonate resin pellet for optical discs in the range of 1 mm has been proposed. In this document, it is described that the pellet aggregate with such a small amount of fine powder does not involve air entrainment during plasticization, and an optical disk substrate free from silver streak is obtained. However, the shape of the pellet is described. It has not been.

In Patent Document 8, in order to shorten the molding cycle of the optical disk substrate, the average value of the pellet length is 2.5 to 3.5 mm, the average value of the major axis of the cross-sectional ellipse is 2.60 to 3.2 mm, A polycarbonate molding material for an optical disk substrate has been proposed in which 70% or more of the pellets are contained in an average length ± 0.08 mm and an average long diameter ± 0.12 mm. In the same document, by setting the length and the major axis of the pellet within the above range, a balanced three-dimensional shape with a ratio of the major axis to the major axis of about 0.7 to 1.5 is obtained, and the distribution is a narrow range. As a result, it is composed of a very uniform shape, and as a result, the shape is more suitable for the cylinder and screw structure of the disk injection molding machine, the melting efficiency during plasticization is increased and the plasticization time It is described that an optical disk substrate can be manufactured by so-called high cycle molding with a short molding cycle. Patent Document 8 is also characterized in that the pellet aggregate has a uniform shape, but there is no description of the details of the elliptical shape of the individual pellets, and the specific manufacturing method of the pellets is simply a strand. It only describes that it is cut and manufactured.

And as in the inventions described in these Patent Documents 7 to 8, it is important to reduce the fine powder in the pellet aggregate as much as possible for thin-walled optical parts such as a light guide. It is not sufficient as a polycarbonate resin pellet for a thin-walled optical component in which yellowing and optical fluctuation are unlikely to occur.

JP-A-11-158364 Japanese Patent Laid-Open No. 2001-208917 JP 2001-215336 A JP-A-1-22959 JP-A-9-227785 Japanese Patent No. 4069364 Japanese Patent Application Laid-Open No. 07-52272 JP 11-035692 A

The present invention has been made in view of the above circumstances, and an object thereof is to provide a polycarbonate resin composition for a thin-walled optical component having good transmittance and hue without impairing the original properties of the polycarbonate resin. .
In addition, the present invention can process a low molecular weight polycarbonate resin with low mechanical strength into a shape that generates a relatively small amount of fine powder even when the pellets contact each other, and can be used to form a light guide. Accordingly, it is an object of the present invention to provide a polycarbonate resin pellet for a thin-walled optical component in which yellowing of a molded product and optical fluctuation are unlikely to occur. Moreover, it is providing the method of manufacturing such a pellet stably.

As a result of intensive studies to achieve the above-mentioned problems, the present inventor contains a specific amount of a polyalkylene ether glycol in a polycarbonate resin and a specific amount of a phosphorus stabilizer. It has been found that better transmission, good hue and very good heat discoloration can be achieved.
Moreover, when producing pellets of such a polycarbonate resin composition, the strand cross-sectional shape at the time of extrusion is flattened to give the strands elasticity and to prevent cracking during cooling, so that the pellets for thin optical components Can be manufactured stably. And by making the pellet shape after pelletizing into a specific flat shape, it is found that it is difficult to pulverize even by contact between pellets, and as a result, yellowing of the molded product, light guides that hardly cause optical fluctuations, etc. It was found that it is extremely excellent as a pellet for thin optical parts.

The present invention provides the following polycarbonate resin composition for thin optical parts, thin optical parts, methods for producing thin optical parts, polycarbonate resin pellets for thin optical parts, and methods for producing polycarbonate resin pellets for thin optical parts.

[1] 0.1 to 2 parts by mass of a polyalkylene ether glycol compound (B) represented by the following general formula (1) and 0 of a phosphorus stabilizer (C) with respect to 100 parts by mass of a polycarbonate resin (A) A polycarbonate resin composition for thin optical parts, characterized by containing 0.005 to 0.5 parts by mass.

(Wherein X and Y represent a hydrogen atom, an aliphatic acyl group or an alkyl group having 1 to 22 carbon atoms, X and Y may be different from each other, m is an integer of 3 to 6, and n is Represents an integer of 6 to 100.)

[2] Furthermore, 0.0005 to 0.2 parts by mass of the epoxy compound (D) is contained, and the mass ratio (C) / (D) of the content of the phosphorus stabilizer (C) and the epoxy compound (D) is The polycarbonate resin composition for thin-walled optical parts according to the above [1], which is 0.5 to 10.
[3] The polycarbonate resin composition for thin-walled optical parts according to the above [1] or [2], wherein the polycarbonate resin (A) has a viscosity average molecular weight (Mv) of 10,000 to 15,000.
[4] The polycarbonate resin composition for thin-walled optical components according to any one of the above [1] to [3], wherein the polycarbonate resin (A) has a viscosity average molecular weight (Mv) of 11,000 to 14,500.
[5] The polycarbonate resin composition for thin-walled optical components according to any one of the above [1] to [4], wherein the polyalkylene ether glycol compound (B) is polytetramethylene ether glycol.
[6] The polycarbonate resin composition for thin-walled optical parts according to any one of [1] to [5] above, wherein the phosphorus stabilizer (C) is a stabilizer having a pentaerythritol diphosphite structure.
[7] The polycarbonate resin composition for thin-walled optical components according to any one of the above [1] to [6], wherein the spectral transmittance at a wavelength of 420 nm measured with an optical path length of 300 mm is 55% or more.

[8] A thin-walled optical component obtained by molding the polycarbonate resin composition according to any one of [1] to [7] above.
[9] The thin optical component according to [8], which is a light guide plate having a thickness of 1 mm or less.

[10] A method for producing a thin optical component having a thickness of 1 mm or less, wherein the polycarbonate resin composition according to any one of [1] to [7] is injection molded at 305 to 380 ° C.
[11] An elliptical columnar pellet made of the polycarbonate resin composition according to any one of [1] to [7] above, having a length of 2.0 to 5.0 mm and having an elliptical cross section A polycarbonate resin pellet for a thin-walled optical component, wherein the ratio of major axis / minor axis is 1.5 to 4 and the minor axis is 1.0 to 3.0 mm.
[12] The polycarbonate resin pellet is fixed in a 50 liter tumbler, which is stored in a 2 liter polyethylene sealed container having an outer diameter of 125 mm and a total height of 233 mm containing 500 g of the polycarbonate resin pellet. The polycarbonate resin pellet for thin optical parts as described in [11] above, wherein the amount of fine powder having a particle diameter of 1 mm or less generated after rotating for 20 minutes is 50 ppm or less.
[13] The polycarbonate resin pellet for thin-walled optical components according to [11] or [12] above, wherein the ratio of the major axis / minor axis of the elliptical cross section of the pellet is 1.8 to 4.

[14] A method for producing a resin pellet as described in any one of [11] to [13] above, wherein a polycarbonate resin having a viscosity average molecular weight of 10,000 to 15,000 is used as a tip of an extruder. A thin wall characterized by being extruded as a strand from a discharge nozzle having an elliptical die hole provided in a cross section with the major axis of the elliptical section in a substantially horizontal state, cooled and solidified in a cooling water tank, and cut with a strand cutter A method for producing polycarbonate resin pellets for optical parts.
[15] When the height difference of the support supporting the strand at a strand take-up speed of 100 mm / sec is 290 mm, the strand does not break in continuous operation for 1 hour or more, and the interval between the supports of the same height is 300 mm or less [14] The method for producing polycarbonate resin pellets for thin-walled optical components according to [14].

According to the present invention, the polycarbonate resin composition for thin optical components having good transmittance and hue and good heat discoloration and thin wall having good transmittance and hue are obtained without impairing the original properties of the polycarbonate resin. An optical component can be provided, and can be particularly suitably used for a thin optical component represented by a light guide plate. The

Although the polycarbonate resin pellets of the present invention have a low viscosity average molecular weight of 10,000 to 15,500, they are difficult to be pulverized by contact between the pellets, resulting in yellowing of the molded product and optical fluctuations. It is extremely excellent as a pellet for thin optical parts such as difficult light guides. In addition, when producing pellets, it is possible to stably produce pellets for thin-walled optical components by flattening the cross-sectional shape of the strand at the time of extrusion, thereby giving elasticity to the strand and making it difficult to break during cooling. it can.

FIG. 1 is a schematic diagram of a polycarbonate resin pellet for a thin-walled optical component according to the present invention. FIG. 2 is a conceptual diagram of a process for producing a polycarbonate resin pellet by extruding a strand from an extruder and a method for evaluating the limit strength. FIG. 3 is a conceptual diagram showing details of the limit strength evaluation method.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples.
In the specification of the present application, unless otherwise specified, “˜” is used to mean that the numerical values described before and after it are included as the lower limit value and the upper limit value.

[Overview]
The polycarbonate resin composition for thin optical components of the present invention is 0.1 to 2 parts by mass of the polyalkylene ether glycol compound (B) represented by the general formula (1) with respect to 100 parts by mass of the polycarbonate resin (A). And 0.005 to 0.5 parts by mass of the phosphorus stabilizer (C).
Hereafter, each component etc. which comprise the polycarbonate resin composition of this invention are demonstrated 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 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, 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.

Examples of aromatic dihydroxy compounds among monomers used as raw materials for aromatic polycarbonate resins are:

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, 1, , 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) Dihydroxydiaryl 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 preferable, and 2,2-bis (4-hydroxyphenyl) propane (particularly 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- Aralkyldiols 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 -1,2-epoxycyclohexane, 2,3-epoxynorbornane, cyclic ethers such as 1,3-epoxypropane; and the like.

Among the monomers used as the raw material for the polycarbonate resin, carbonyl halides, carbonate esters and the like are used as examples of carbonate precursors. 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 the carbonyl halide include phosgene; haloformates such as a bischloroformate of a dihydroxy compound and a monochloroformate of a dihydroxy compound.

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, 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.

The concentration of the alkali compound in the alkaline aqueous solution is not limited, but it is usually used at 5 to 10% by mass in order to control the pH in the alkaline aqueous solution of the reaction to 10 to 12. For example, when phosgene is blown, the molar ratio of the bisphenol compound to 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 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, among which 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 isopropenyl 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 amount used of the molecular weight regulator is usually 0.5 mol or more, preferably 1 mol or more, and usually 50 mol or less, preferably 30 mol or less, per 100 mol of the dihydroxy compound. 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.
The reaction temperature is usually 0 to 40 ° C., and the reaction time is usually several minutes (for example, 10 minutes) to 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 polycarbonate resins, the amount of terminal hydroxyl groups tends to have a large effect 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 a polycarbonate resin is produced 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 molecular weight of the polycarbonate resin (A) is preferably 10,000 to 15,000 in terms of viscosity average molecular weight (Mv) converted from the solution viscosity measured at a temperature of 25 ° C. using methylene chloride as a solvent. Preferably it is 10,500 or more, More preferably, it is 11,000 or more, Especially, 11,500 or more, Most preferably, it is 12,000 or more, More preferably, it is 14,500 or less. 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 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 the terminal hydroxyl group concentration represents the mass of the terminal hydroxyl group with respect to the mass of the polycarbonate resin in ppm. The measuring method is a colorimetric determination by the titanium tetrachloride / acetic acid method (method described in Macromol. Chem. 88 215 (1965)).

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 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 ether glycol compound (B)]
The polycarbonate resin composition for thin optical parts of the present invention contains a polyalkylene ether glycol compound (B) represented by the following general formula (1).

In the general formula (1), n (degree of polymerization) is an integer of 6 to 100, preferably 8 or more, more preferably 10 or more, preferably 90 or less, more preferably 80 or less. A polymerization degree n of less than 6 is not preferable because gas is generated during molding. On the other hand, when the polymerization degree n exceeds 100, the compatibility is lowered, which is not preferable.
The polyalkylene ether glycol compound (B) may be a copolymer with another copolymer component, but a polyalkylene ether glycol homopolymer is preferred.

As polyalkylene ether glycol compound (B), in formula (1), X and Y are hydrogen atoms, m is 3, polytrimethylene ether glycol, m is 4, polytetramethylene ether glycol, m is 5 Preferably, polypentamethylene ether glycol is m, and polyhexamethylene ether glycol in which m is 6, more preferably polytrimethylene ether glycol, polytetramethylene ether glycol, particularly preferably polytetramethylene ether glycol or an esterified product thereof. Or an etherified product.

In addition, as the polyalkylene ether glycol compound (B), even if one or both ends thereof are blocked with a fatty acid or alcohol, there is no influence on the performance expression, and a fatty acid ester or ether can be used in the same manner. It may be an aliphatic acyl group or an alkyl group having X and / or 1 to 22 carbon atoms in 1).

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 22 carbon atoms, for example, 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.
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 polyalkylene ether glycol fatty acid ester include polyalkylene ether glycol monopalmitate, polyalkylene ether glycol dipalmitate, polyalkylene ether glycol monostearate, polyalkylene ether glycol distearate, polyalkylene Examples include ether glycol (monopalmitic acid / monostearic acid) ester, polyalkylene ether glycol behenate, and the like.

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 alkyl methyl ether, ethyl ether, butyl ether, lauryl ether and stearyl ether of polyalkylene ether glycol.

The number average molecular weight of the polyalkylene ether glycol compound (B) is preferably 200 to 5,000, more preferably 300 or more, still more preferably 500 or more, more preferably 4,000 or less, More preferably, it is 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 a polyalkylene ether glycol compound here is the number average molecular weight computed based on the hydroxyl value measured based on JISK1577.

The content of the polyalkylene ether glycol compound (B) is 0.1 to 2 parts by mass with respect to 100 parts by mass of the 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 part by mass, the hue and yellowing are not sufficiently improved. When the content exceeds 2 parts by mass, strand breakage frequently occurs during melt kneading by an extruder, and the resin composition pellets It becomes difficult to create.

[Phosphorus stabilizer (C)]
The polycarbonate resin composition of the present invention needs to contain a phosphorus stabilizer. By containing a phosphorus stabilizer, the hue of the polycarbonate resin composition of the present invention is improved, 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 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 and the like 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. 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 ratios.

The content of the phosphorus stabilizer (C) is 0.005 to 0.5 parts by mass, preferably 0.007 parts by mass or more, more preferably 0.005 parts by mass with respect to 100 parts by mass of the polycarbonate resin (A). 008 parts by mass or more, particularly preferably 0.01 parts by mass or more, preferably 0.4 parts by mass or less, more preferably 0.3 parts by mass or less, still more preferably 0.2 parts by mass or less, particularly 0 .1 part by mass or less. When the content of the phosphorus stabilizer (C) 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 (C) 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.

[Epoxy compound (D)]
The polycarbonate resin composition of the present invention preferably further contains an epoxy compound (D). By containing an epoxy compound, the hue of the polycarbonate resin composition of the present invention becomes better, and the heat discoloration is further improved.

As the epoxy compound (D), a compound having one or more epoxy groups in one molecule is used. Specifically, phenyl glycidyl ether, allyl glycidyl ether, t-butylphenyl glycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexylcarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl -3 ', 4'-epoxy-6'-methylcyclohexyl carboxylate, 2,3-epoxycyclohexylmethyl-3', 4'-epoxycyclohexyl carboxylate, 4- (3,4-epoxy-5-methylcyclohexyl) Butyl-3 ′, 4′-epoxycyclohexylcarboxylate, 3,4-epoxycyclohexylethylene oxide, cyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6 ′ -Methylsiloxyl carboxylate, bisphenol-A diglycidyl ether, tetrabromobisphenol-A glycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, bis-epoxy dicyclopentadienyl ether, bis- Epoxyethylene glycol, bis-epoxycyclohexyl adipate, butadiene diepoxide, tetraphenylethylene epoxide, octyl epoxytalate, epoxidized polybutadiene, 3,4-dimethyl-1,2-epoxycyclohexane, 3,5-dimethyl-1,2, -Epoxycyclohexane, 3-methyl-5-t-butyl-1,2-epoxycyclohexane, octadecyl-2,2-dimethyl-3,4-epoxycyclohexylcarboxy N-butyl-2,2-dimethyl-3,4-epoxycyclohexyl carboxylate, cyclohexyl-2-methyl-3,4-epoxycyclohexyl carboxylate, N-butyl-2-isopropyl-3,4-epoxy -5-methylcyclohexyl carboxylate, octadecyl-3,4-epoxycyclohexyl carboxylate, 2-ethylhexyl-3 ', 4'-epoxycyclohexyl carboxylate, 4,6-dimethyl-2,3-epoxycyclohexyl-3', 4'-epoxycyclohexylcarboxylate, 4,5-epoxytetrahydrophthalic anhydride, 3-tert-butyl-4,5-epoxytetrahydrophthalic anhydride, diethyl 4,5-epoxy-cis-1,2-cyclohexyldicarboxylate Rate, j-n-b Le -3-t-butyl-4,5-epoxy - cis-1,2-cyclohexyl dicarboxylate, epoxidized soybean oil, can be preferably exemplified such as epoxidized linseed oil.
Epoxy compounds may be used alone or in combination of two or more.

The content of the epoxy compound (D) is preferably 0.0005 to 0.2 parts by mass, more preferably 0.001 parts by mass or more, and still more preferably 0 with respect to 100 parts by mass of the polycarbonate resin (A). 0.003 parts by mass or more, particularly preferably 0.005 parts by mass or more, more preferably 0.15 parts by mass or less, still more preferably 0.1 parts by mass or less, particularly preferably 0.05 parts by mass or less. . When the content of the epoxy compound (D) is less than 0.0005 parts by mass, the hue and the heat discoloration tend to be insufficient, and when it exceeds 0.2 parts by mass, the heat discoloration is not only deteriorated. Also, hue and wet heat stability are likely to decrease.

[Ratio of content of phosphorus stabilizer (C) and epoxy compound (D)]
When the epoxy compound (D) is contained, the ratio of the content of the phosphorus stabilizer (C) and the epoxy compound (D) in the polycarbonate resin composition is a mass ratio of (C) / (D). A range of 0.5 to 10 is preferable. When the mass ratio of (C) / (D) is less than 0.5, the hue, particularly the initial YI value, tends to deteriorate, and when it exceeds 10, the heat discoloration tends to deteriorate. The mass ratio of (C) / (D) is more preferably 0.7 or more, further preferably 0.8 or more, more preferably 8 or less, still more preferably 7 or less, and particularly preferably 8 It is as follows.

[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, and polycarbonate resin (A), polyalkylene ether glycol (B), and phosphorus stabilizer (C) , And other ingredients to be blended as necessary, for example, by using various mixers such as a tumbler and a Henschel mixer, then Banbury mixer, roll, Brabender, single screw kneading extruder, twin screw kneading extrusion And a melt kneading method using a mixer such as a kneader or a kneader. The temperature for melt kneading is not particularly limited, but is usually in the range of 240 to 320 ° C.

The polycarbonate resin composition for thin optical components of the present invention exhibits high spectral transmittance, and the spectral transmittance measured at an optical path length of 300 mm at a wavelength of 420 nm is preferably 55% or more, more preferably 56% or more, and further Preferably, it can have a high spectral transmittance of 57% or more.
The spectral transmittance at a wavelength of 420 nm is a transmittance in a wavelength region close to the wavelength region of a blue LED often used in optical components such as a light guide plate, and if the transmittance in this wavelength region is low, yellowishness Will increase.
The spectral transmittance at a wavelength of 420 nm is measured with an optical path length of 300 mm using an injection molded long optical path molded product (300 mm × 7 mm × 4 mm), and is specifically performed according to the method described in the examples described later. .

[Polycarbonate resin pellets]
The polycarbonate resin composition for thin optical parts of the present invention is usually formed into pellets by melting and kneading each component as described above. The polycarbonate resin pellet is preferably a pellet having an elliptical columnar shape.
FIG. 1 is a schematic diagram of the polycarbonate resin pellet for thin-walled optical components.
A preferred polycarbonate resin pellet has a length L in the range of 2.0 to 5.0 mm, and a ratio of the major axis d to the minor axis a (d / a) in the elliptical cross section of the pellet is in the range of 1.5 to 4. And the minor axis a is in the range of 1.0 to 3.0 mm.

If the length L is not in the range of 2.0 to 5.0 mm, the pellets are easily crushed and the amount of fine powder generated tends to increase. If the ratio of the major axis d to the minor axis a (d / a) deviates from the range of 1.5 to 4, the strength of the resin strands tends to decrease, the production of pellets by extrusion becomes unstable, and the elliptical minor axis a If it is not within the range of 1.0 to 3.0 mm, the pellets are easily crushed and the amount of fine powder generated tends to increase.
The ratio of the major axis d to the minor axis a (d / a) is preferably 1.6 or more, more preferably 1.7 or more, still more preferably 1.8 or more, and preferably 3.5 or less. Yes, more preferably 3.0 or less.

Such a polycarbonate resin pellet has such a shape that the pellet is accommodated in a paper bag, a flexible container, or the like, and it is difficult to generate fine powder even when subjected to vibration or load when transporting and delivering it. Have. Since the major axis direction of the elliptical cross section of the pellet becomes horizontal and receives the load, it is considered that it is difficult to pulverize.
The amount of fine powder generation of such polycarbonate resin pellets is as follows: 500 g of resin pellets are housed in a 2 liter polyethylene sealed container having an outer diameter of 125 mm and a total height of 233 mm, and placed in a 50 liter tumbler and fixed. The amount of fine powder having a particle diameter of 1 mm or less that is generated after rotating at a rotational speed for 20 minutes is preferably 50 ppm or less.

[Manufacture of polycarbonate resin pellets]
As a method for producing the polycarbonate resin pellet, various methods can be applied, and a preferred embodiment will be described below.

The polycarbonate resin is stored in a raw material supply machine, and from there, is fed to the extruder by a feeder (quantitative feeder) from a hopper installed on the extruder. The polycarbonate resin may be in the form of pellets or powder.
Other components other than the polycarbonate resin can be blended at any stage before being charged into the extruder. For example, after all components are blended by a tumbler, a Henschel mixer, and a blender, they may be fed into a hopper chute via a feeder and supplied to an extruder as necessary. As the extruder, a single screw extruder, a twin screw extruder or the like can be used. Moreover, you may supply to a hopper chute | shoot with the path | route different from polycarbonate resin.

The extruder may be a single screw extruder or a twin screw extruder, but a twin screw extruder is preferred. The L / D of the screw of the extruder is preferably 10 to 80, more preferably 15 to 70, and still more preferably 20 to 60. If the screw is too short, deaeration tends to be insufficient, and if it is too long, the color tone tends to deteriorate.

Next, the polycarbonate resin composition is extruded in a strand shape from the discharge nozzle at the tip of the extruder, and it is preferable to use a die having an elliptical die hole as the die of the discharge nozzle. By changing the flatness of the elliptical die hole of the discharge nozzle, the flatness of the pellet can be changed.

The dies of the discharge nozzle are preferably extruded by attaching the major axis of the elliptical die hole in a substantially horizontal state, and attaching the strand having an elliptical cross section to be extruded so that the major axis is substantially horizontal. The temperature of the polycarbonate resin immediately after being extruded is usually about 300 ° C.
The strand having an elliptical cross-section has a major axis that is substantially horizontal and is taken up by a take-up roller, and is cooled by being transported through the water stored in the cooling water tank. In order to reduce the deterioration of the resin, it is better that the time from when the strand is pushed out of the die until entering the water is shorter. Normally, it is better to enter the water within 1 second after being pushed out of the die.

The cooled strand is sent to a pelletizer by a take-up roller, cut to a pellet length of 2.0 to 5.0 mm, and made into a pellet.

FIG. 2 is a conceptual diagram showing a process for producing a polycarbonate resin pellet by extruding a strand from an extruder, and FIG. 3 is a conceptual diagram showing details of a limit strength evaluation method.
After the polycarbonate resin pellets are extruded from the discharge nozzle 2 of the extruder, the strand 1 is introduced into the cooling water tank 3 and cooled. Then, the strand 1 is taken up while being supported by the support C, B, A of the take-up roller in order. Sent. At this time, when the strand take-up speed (Vx) is 100 mm / sec and the height difference between the support C at the same height supporting the strand 1 and the support B between A and C-A is 290 mm, one hour or more It is preferable that an interval (X mm, hereinafter also referred to as “limit interval”) defined as an interval between the support C and the support A where the strand is not broken by continuous operation is 300 mm or less.

[Thin optical components]
The polycarbonate resin composition for thin optical components of the present invention can be produced by molding pellets obtained by pelletizing the above-described polycarbonate resin composition by various molding methods. Further, the resin melt-kneaded by an extruder can be directly molded into a thin optical component without going through the pellets.

The polycarbonate resin composition of the present invention has excellent fluidity, and even when it is a thin molded product, it has excellent appearance of a molded product without white spot foreign matter, and can achieve both transmittance and hue. It is suitably used for molding optical components. 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. In the case of using a conventional polycarbonate resin composition, there is a problem that white spot foreign matter tends to be generated on the surface of the molded product when the resin temperature at the time of molding is increased in order to mold a thin molded product. By using the resin composition of the invention, it is possible to produce a thin molded article having a good appearance 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.

In the present invention, the thin-walled molded article refers to a molded article having a plate-like 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.

Thin-walled optical parts include parts of equipment and instruments that directly or indirectly use light sources such as LEDs, organic EL, incandescent bulbs, fluorescent lamps, cathode tubes, etc., and typical examples include light guide plates and surface light emitter parts. 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 does not have white turbidity or a decrease in transmittance, and has a very good transmittance and hue.

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.

(Examples 1 to 7, Comparative Examples 1 to 5)
The raw materials used are as shown in Table 1 below.
The viscosity average molecular weight of the polycarbonate resin (A) was determined from the following equation by measuring the intrinsic viscosity [η] at 20 ° C. in methylene chloride using an Ubbelohde viscometer.
[Η] = 1.23 × 10 ⁻⁴ × (Mv) ^0.83

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

[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) and spectral transmittance (unit:%) at a wavelength of 420 nm were measured with 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.

[Comparative Example 5]
In Example 1, except that the B1 component was changed to 4 parts by mass, pelletization was examined in the same manner as in Example 1. However, strand breakage occurred frequently during melt-kneading by an extruder, and the resin composition pellets Creation was difficult.

As is apparent from Table 2, the molded product of the example has a small YI at 300 mm with a long optical path length, and shows little yellowing. Furthermore, the light transmittance at 420 nm is high and the transparency is excellent.
On the other hand, in the comparative example of Table 3, it can be seen that YI of 300 mm is worse than that of the example. Furthermore, the light transmittance is also low.

(Examples 8 to 14, Comparative Examples 6 to 7, Reference Examples 1 to 3)
The raw materials used are as shown in Table 4 below.

[Production of resin composition pellets]
Each component described above was blended in the proportions (parts by mass) shown in Tables 5 and 6, mixed for 20 minutes with a tumbler, and then a single screw extruder with a vent with a screw diameter of 40 mm (“VS” manufactured by Tanabe Plastic Machinery Co., Ltd.). −40 ”) was melt-kneaded at a cylinder temperature of 240 ° C., and pellets were obtained by strand cutting.

[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.
With respect to this long optical path molded product, YI (yellowing degree) (hereinafter, “initial YI”) and spectral transmittance (unit:%) at a wavelength of 420 nm were measured with 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, the long optical path molded product was held at 85 ° C. for 800 hours, and then YI was measured with a 300 mm optical path length (post-treatment YI) to obtain a difference in YI values (ΔYI = post-treatment YI−initial YI).
The above evaluation results are shown in Tables 5 and 6 below.

As is clear from Table 5 above, the thin-walled molded product of the example containing the epoxy compound (D) has a small initial YI at 300 mm having a long optical path length and an excellent hue. Further, it can be seen that the increase in YI value after the heat treatment is small and the heat discoloration is excellent.

(Example 15)
Each component described in Table 1 above was blended in the proportions (parts by mass) described in Example 5 of Table 2 above, mixed for 20 minutes with a tumbler, and then vented twin screw extruder (manufactured by Nippon Steel Works). “TEX44αII”) is continuously supplied to the extruder from the hopper, melted and mixed in the extruder, and the major axis is 6.5 mm under the extrusion conditions of a cylinder temperature of 240 ° C., a discharge rate of 150 kg / h, and a screw speed of 250 rpm. A die having an elliptical die hole with a diameter of 3.5 mm is extruded from an extrusion nozzle provided with its major axis horizontal, in a strand shape with the major axis of the elliptical cross section approximately horizontal, introduced into a cooling water tank, and a strand The pellet was cut with a pelletizer at a take-up speed of 40 m / min and a cutter blade rotation speed of 600 rpm to obtain polycarbonate resin pellets.

(1) Major axis / minor axis ratio of pellet elliptical cross section The major axis, minor axis, and length of the obtained pellet were measured, and an average value of 100 was shown for each. The ratio of the average value of the major axis / minor axis was defined as the pellet flatness.
The major axis of the pellet was 2.9 mm, the minor axis was 1.5 mm, the pellet length was 2.9 mm, and the ratio of major axis / minor axis was 1.9.

(2) Stability of the strand The strand coming out of the die is extruded straight by pressing the support against the strand and applying a certain load to prevent meandering without determining the direction of extrusion. I am doing so.
In this state, the number of strand breaks per hour was counted to evaluate the extrusion stability.
The number of strand breaks was 0.

(3) Limit strength of strand Moreover, the limit strength of the strand was evaluated by the following method.
As shown in FIG. 2, the resin strand obtained by extruding the obtained polycarbonate resin pellets from the extruder is sent to the pelletizer while being supported by the support C to the support B and the support A. As shown in detail in FIG. 3, the critical strength of the resin strand is that the strand take-up speed (Vx) is 100 mm / sec, and the height difference between the support C and A and the support B at the same height supporting the strand is 290 mm. At the time, it was evaluated as an interval (X mm) between the support C and the support A at the same height where the strands were not broken by continuous operation for 1 hour or more.
The support spacing was 260 mm.

(4) Measurement of the amount of fine powder generated by a vibration test 500 g of the obtained polycarbonate resin pellets were stored in a 2 liter polyethylene sealed container having an outer diameter of 125 mm and a total height of 233 mm, and a 50 liter tumbler (Seiwa Iron Works Co., Ltd.) (“SKD-50” manufactured) and fixed at 30 rpm for 20 minutes to rub the pellets and generate fine powder.
For the measurement of the amount of fine powder, 500 g of pellets after vibration test were put in 1 liter of liquid mixed with water and ethyl alcohol in a 1: 1 ratio and stirred sufficiently, and then the supernatant liquid containing the fine powder of the pellet was filtered using a filter paper. The mass after the filter paper was dried in an oven at 120 ° C. for 2 hours was measured, and the amount of adhering fine powder (mass ppm) was calculated from the net increase in the weight of the filter paper. The particle size of the fine powder in this measurement is 1 mm or less.
The amount of fine powder generated was 35 ppm by mass.

(5) Poor white spot Using the obtained polycarbonate resin pellets, a thin flat plate of 100 mm x 100 mm x 0.4 mm thickness is molded at a temperature of 340 ° C by an injection molding machine ("EC100SX-2A" manufactured by Toshiba Machine Co., Ltd.) Then, the number (number of sheets) of white spot defects per 10 sheets was counted.
There were no white spot defects.

(6) Vacuum Void About 100 obtained polycarbonate resin pellets, visual observation was performed and the number of the pellets in which a vacuum void exists was counted.
The number of pellets in which vacuum voids were present was zero.

(Example 16)
Each component described in Table 1 above was blended in the proportions (parts by mass) described in Example 7 in Table 2 above, mixed for 20 minutes with a tumbler, and then vented twin screw extruder (manufactured by Nippon Steel Works). “TEX44αII”) is continuously supplied to the extruder from the hopper, melted and mixed in the extruder, and the major axis is 6.5 mm under the extrusion conditions of a cylinder temperature of 240 ° C., a discharge rate of 150 kg / h, and a screw speed of 250 rpm. A die having an elliptical die hole with a diameter of 2.9 mm was extruded from an extrusion nozzle provided with the major axis horizontal, in a strand shape with the major axis of the elliptical section approximately horizontal, introduced into a water tank, and the strand The pellet was cut by a pelletizer at a take-up speed of 40 m / min and a cutter blade rotation speed of 600 rpm to obtain polycarbonate resin pellets.

The major axis of the pellet was 2.9 mm, the minor axis was 1.2 mm, the length of the pellet was 3.2 mm, and the ratio of major axis / minor axis was 2.4.
The number of strand breaks was 0, and the support support interval was 270 mm. The amount of fine powder generated was 34 ppm by mass, the number of white spot defects was zero, and the number of pellets with vacuum voids was zero.

(Example 17)
Each component described in Table 4 above was blended in (parts by mass) in the proportions described in Example 9 in Table 5 above, mixed for 20 minutes with a tumbler, and then vented twin-screw extruder (Nippon Steel Works) Manufactured continuously from a hopper made of “TEX44αII”), melted and mixed in the extruder, under a cylinder temperature of 240 ° C., a discharge amount of 150 kg / h, and an extrusion condition of a screw rotation speed of 250 rpm, a major axis of 6.5 mm, A die having an elliptical die hole with a short diameter of 3.5 mm is extruded from an extrusion nozzle provided with the major axis horizontal, in a strand shape with the major axis of the elliptical section approximately horizontal, and introduced into a water tank. The pellet was cut with a pelletizer at a take-up speed of 40 m / min and a cutter blade rotation speed of 600 rpm to obtain polycarbonate resin pellets.

The major axis of the pellet was 2.9 mm, the minor axis was 1.5 mm, the pellet length was 2.9 mm, and the ratio of major axis / minor axis was 1.9.
The number of strand breaks was 0, and the support support interval was 260 mm. The amount of fine powder generated was 35 ppm by mass, the number of white spot defects was zero, and the number of pellets with vacuum voids was zero.

The polycarbonate resin composition of the present invention has very good transmittance and hue and is excellent in heat discoloration. Therefore, the polycarbonate resin composition can be used suitably for thin-walled optical components and has very high industrial applicability.

Claims

The polyalkylene ether glycol compound (B) represented by the following general formula (1) is 0.1 to 2 parts by mass and the phosphorus stabilizer (C) is 0.005 to 100 parts by mass of the polycarbonate resin (A). A polycarbonate resin composition for thin optical parts, characterized by containing 0.5 parts by mass.

(Wherein X and Y represent a hydrogen atom, an aliphatic acyl group or an alkyl group having 1 to 22 carbon atoms, X and Y may be different from each other, m is an integer of 3 to 6, and n is Represents an integer of 6 to 100.)
Furthermore, 0.0005 to 0.2 parts by mass of the epoxy compound (D) is contained, and the mass ratio (C) / (D) of the content of the phosphorus stabilizer (C) and the epoxy compound (D) is 0.5. The polycarbonate resin composition for thin optical parts according to claim 1, wherein
The polycarbonate resin composition for thin-walled optical parts according to claim 1 or 2, wherein the polycarbonate resin (A) has a viscosity average molecular weight (Mv) of 10,000 to 15,000.
The polycarbonate resin composition for thin-walled optical parts according to any one of claims 1 to 3, wherein the viscosity average molecular weight (Mv) of the polycarbonate resin (A) is 11,000 to 14,500.
The polycarbonate resin composition for thin-walled optical parts according to any one of claims 1 to 4, wherein the polyalkylene ether glycol compound (B) is polytetramethylene ether glycol.
The polycarbonate resin composition for thin-walled optical parts according to any one of claims 1 to 5, wherein the phosphorus stabilizer (C) is a stabilizer having a pentaerythritol diphosphite structure.
The polycarbonate resin composition for thin-walled optical parts according to any one of claims 1 to 6, wherein the spectral transmittance at a wavelength of 420 nm measured with an optical path length of 300 mm is 55% or more.
A thin optical component obtained by molding the polycarbonate resin composition according to any one of claims 1 to 7.
The thin optical component according to claim 8, which is a light guide plate having a thickness of 1 mm or less.
A method for producing a thin optical part having a thickness of 1 mm or less, wherein the polycarbonate resin composition according to any one of claims 1 to 7 is injection-molded at 305 to 380 ° C.
An elliptical columnar pellet made of the polycarbonate resin composition according to any one of claims 1 to 7, having a length of 2.0 to 5.0 mm, and a ratio of major axis / minor axis of the elliptical section. A polycarbonate resin pellet for thin-walled optical parts, characterized in that the diameter is 1.5 to 4 and the minor axis is 1.0 to 3.0 mm.
The polycarbonate resin pellets are fixed in a 50 liter tumbler which is contained in a 2 liter polyethylene sealed container having an outer diameter of 125 mm and a total height of 233 mm containing 500 g of the polycarbonate resin pellets, and is rotated at 30 rpm for 20 minutes. The polycarbonate resin pellet for thin-walled optical components according to claim 11, wherein the amount of fine powder having a particle size of 1 mm or less generated after rotation is 50 ppm or less.
The polycarbonate resin pellet for thin-walled optical parts according to claim 11 or 12, wherein the ratio of the major axis / minor axis of the cross-sectional ellipse of the pellet is 1.8 to 4.
A method for producing the resin pellet according to any one of claims 11 to 13, wherein a polycarbonate resin having a viscosity average molecular weight of 10,000 to 15,000 is provided in an elliptical shape provided at the tip of the extruder. A polycarbonate resin pellet for thin-walled optical parts, characterized in that it is extruded as a strand from a discharge nozzle having a die hole, with the major axis of the ellipse in a substantially horizontal state, extruded as a strand, cooled and solidified in a cooling water tank, and cut with a strand cutter Manufacturing method.
The distance between supports of the same height is 300 mm or less, in which the strands do not break in continuous operation for 1 hour or more when the height difference of the support supporting the strand at the strand take-up speed of 100 mm / sec is 290 mm. The manufacturing method of the polycarbonate resin pellet for thin optical components of description.