JP2016210934A - Polycarbonate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition which has high levels of electromagnetic wave-shielding properties and is excellent in flowability, a strength and rigidity.SOLUTION: There is provided the polycarbonate resin composition that contains 10-100 pts.mass of a carbon fiber (B) with respect to 100 pts.mass of a polycarbonate resin (A), and that is produced by using a carbon fiber which is treated with a polyurethane-based or epoxy-based sizing agent and has a fiber length of 1-8 mm as the carbon fiber (B), as a raw material, and melting and kneading the carbon fiber. In the polycarbonate resin composition, a mass-average fiber length of the carbon fiber in the resin composition is in the range of 800-3,000 μm.SELECTED DRAWING: None

Description

  The present invention relates to a polycarbonate resin composition and a molded article, and more particularly to a polycarbonate resin composition having high electromagnetic shielding properties and excellent fluidity, strength, and rigidity.

  Polycarbonate resin is excellent in impact resistance, heat resistance, electrical insulation, dimensional stability, etc., and has a good balance of these characteristics. Therefore, electrical and electronic equipment parts, precision machine parts, vehicle parts, OA equipment parts. Widely used in such fields.

  In particular, in electronic devices such as personal computers, various portable terminals, and digital cameras, high integration, high density, and high-speed processing of circuits accompanying the reduction in size and weight and high performance have been progressing rapidly in recent years. When electromagnetic waves enter the device from the outside, there is a problem of causing malfunctions and arithmetic processing failures. For this reason, the housing | casing etc. of an electronic device have become essential [the function which shields the electromagnetic wave from the outside, and prevents the electromagnetic wave leakage outside].

In order to impart an electromagnetic wave shielding function to a casing or the like of an electronic device, there is a method of conducting electromagnetic coating to shield the electromagnetic wave. However, a complicated coating process is required, and there are drawbacks such as easy peeling of the conductive layer. The method of molding from a resin composition containing a conductive filler is advantageous because it does not require post-processing and there is no fear of peeling, but the electromagnetic properties are insufficient, and if it is contained in a large amount, the mechanical properties are remarkably increased. It will decline.
Patent Document 1 proposes an electromagnetic wave shielding resin composition comprising a carbon fiber (B) metal-coated on a thermoplastic resin (A) such as polycarbonate resin and a metal-coated graphite (C). It is still not enough to solve all the problems of strong electromagnetic shielding, high fluidity (formability), strength and rigidity.

JP 2005-298653 A

  An object (problem) of the present invention is to provide a polycarbonate resin composition having high electromagnetic shielding properties and excellent fluidity, strength and rigidity.

As a result of intensive investigations to achieve the above-mentioned problems, the present inventor uses a carbon fiber having a specific fiber length treated with a polyurethane-based or epoxy-based sizing agent as a raw material for a polycarbonate resin, and is melt-kneaded. In order to complete the present invention, it is found that a polycarbonate resin composition in which the mass average fiber length of carbon fibers in the resin composition is in a specific range solves the above problems. It came.
The present invention provides the following polycarbonate resin composition and molded article.

[1] A polycarbonate resin composition containing 10 to 100 parts by mass of the carbon fiber (B) with respect to 100 parts by mass of the polycarbonate resin (A), and the carbon fiber (B) is a polyurethane-based or epoxy-based sizing agent. A polycarbonate resin produced by melt-kneading a carbon fiber having a fiber length of 1 to 8 mm that is processed and having a mass average fiber length of 800 to 3000 μm in the resin composition. Composition.
[2] The polycarbonate resin composition according to [1], further containing 1 to 25 parts by mass of the flow modifier (C) with respect to 100 parts by mass of the polycarbonate resin (A).
[3] The polycarbonate resin composition according to the above [2], wherein the flow modifier (C) is selected from an acrylonitonyl-styrene copolymer, a polycarbonate oligomer, and polycaprolactone.
[4] The polycarbonate resin composition according to the above [1], wherein the carbon fiber (B) raw material has a fiber diameter of 3 to 10 μm.
[5] The polycarbonate resin composition according to [1], wherein the content of the polyurethane-based or epoxy-based sizing agent is 1 to 10 parts by mass based on a total of 100% by mass of the carbon fiber (B) and the sizing agent. .
[6] The polycarbonate resin composition according to the above [1], wherein the ratio of the discharge amount of the extruder and the screw rotation number (screw rotation number / discharge amount) at the time of manufacturing by melt-kneading is 5 or less. .
[7] A molded product formed by molding the polycarbonate resin composition according to any one of [1] to [6].

  The polycarbonate resin composition of the present invention has a high degree of electromagnetic shielding properties and is excellent in fluidity, strength and rigidity.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention is not limited to the following embodiments and examples and the like, and is within the scope of the present invention. Any change can be made.

[Overview]
The polycarbonate resin composition of the present invention is a polycarbonate resin composition containing 10 to 100 parts by mass of carbon fiber (B) with respect to 100 parts by mass of polycarbonate resin (A). Or it is manufactured by melt-kneading using carbon fiber having a fiber length of 1 to 8 mm treated with an epoxy-based sizing agent as a raw material, and the mass average fiber length of the carbon fiber in the resin composition is in the range of 800 to 3000 μm. It is characterized by.

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

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

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

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

  Among monomers used as raw materials for aromatic polycarbonate resins, examples of aromatic dihydroxy compounds include:

Dihydroxybenzenes such as 1,2-dihydroxybenzene, 1,3-dihydroxybenzene (ie, resorcinol), 1,4-dihydroxybenzene;
Dihydroxybiphenyls such as 2,5-dihydroxybiphenyl, 2,2′-dihydroxybiphenyl, 4,4′-dihydroxybiphenyl;

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

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

2,2-bis (4-hydroxyphenyl) propane (ie, bisphenol A),
1,1-bis (4-hydroxyphenyl) propane,
2,2-bis (3-methyl-4-hydroxyphenyl) propane,
2,2-bis (3-methoxy-4-hydroxyphenyl) propane,
2- (4-hydroxyphenyl) -2- (3-methoxy-4-hydroxyphenyl) propane,
1,1-bis (3-tert-butyl-4-hydroxyphenyl) propane,
2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane,
2,2-bis (3-cyclohexyl-4-hydroxyphenyl) propane,
2- (4-hydroxyphenyl) -2- (3-cyclohexyl-4-hydroxyphenyl) propane,
α, α′-bis (4-hydroxyphenyl) -1,4-diisopropylbenzene,
1,3-bis [2- (4-hydroxyphenyl) -2-propyl] benzene,
Bis (4-hydroxyphenyl) methane,
Bis (4-hydroxyphenyl) cyclohexylmethane,
Bis (4-hydroxyphenyl) phenylmethane,
Bis (4-hydroxyphenyl) (4-propenylphenyl) methane,
Bis (4-hydroxyphenyl) diphenylmethane,
Bis (4-hydroxyphenyl) naphthylmethane,
1,1-bis (4-hydroxyphenyl) ethane,
1,1-bis (4-hydroxyphenyl) -1-phenylethane,
1,1-bis (4-hydroxyphenyl) -1-naphthylethane,
1,1-bis (4-hydroxyphenyl) butane,
2,2-bis (4-hydroxyphenyl) butane,
2,2-bis (4-hydroxyphenyl) pentane,
1,1-bis (4-hydroxyphenyl) hexane,
2,2-bis (4-hydroxyphenyl) hexane,
1,1-bis (4-hydroxyphenyl) octane,
2,2-bis (4-hydroxyphenyl) octane,
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 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 produced 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; 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 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 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 a 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.

-Other matters regarding the polycarbonate resin (A) The molecular weight of the polycarbonate resin (A) may be appropriately selected and determined. The viscosity average molecular weight [Mv] is usually 10,000 or more, preferably 16000 or more, more preferably 17000 or more. More preferably, it is 18000 or more, and is usually 40000 or less, preferably 30000 or less.

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

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

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

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

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

Further, the polycarbonate resin may be not only a virgin raw material but also a polycarbonate resin regenerated from a used product (so-called material-recycled polycarbonate resin). Examples of the used products include: optical recording media such as optical disks; light guide plates; vehicle window glass, vehicle headlamp lenses, windshields and other vehicle transparent members; water bottles and other containers; eyeglass lenses; Examples include architectural members such as glass windows and corrugated sheets. Also, non-conforming products, pulverized products obtained from sprues, runners, etc., or pellets obtained by melting them can be used.
However, the regenerated polycarbonate resin is preferably 80% by mass or less, more preferably 50% by mass or less, among the polycarbonate resin (A). 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.

[Carbon fiber (B)]
The polycarbonate resin composition of the present invention contains carbon fiber (B). As the carbon fiber, any of PAN (polyacrylonitrile), pitch, rayon and the like can be used.

  In this invention, what is 1-8 mm is used as fiber length of carbon fiber (B) of a raw material. When the fiber length is in such a range, the resin composition in which the mass average fiber length of the carbon fiber (B) dispersed in the composition produced by melt-kneading the resin composition is within a range of 800 to 3000 μm is produced. Can be manufactured well. The fiber length of the raw carbon fiber (B) is preferably 7.5 mm or less, more preferably 7.0 mm or less, still more preferably 6.5 mm or less, particularly preferably 6 mm or less, and preferably 1.5 mm or more, More preferably, it is 2 mm or more, More preferably, it is 2.5 mm or more. Here, the fiber length of the raw carbon fiber (B) means the number average fiber length, but most commercially available carbon fibers have a uniform fiber length, and the fiber length is determined. For example, a product having a substantially uniform fiber length can be obtained from commercially available products.

  The fiber diameter of the raw carbon fiber (B) is preferably 10 μm or less, more preferably 9 μm or less, still more preferably 8 μm or less, especially 7.5 μm or less, especially 7.0 μm or less, and even 6.5 μm. In particular, the thickness is particularly preferably 6 μm or less, and more preferably 3.5 μm or more and 4 μm or more. When the fiber diameter is in such a range, the strength, particularly the elastic modulus is further improved, and a resin composition excellent in electromagnetic wave shielding properties can be easily obtained. Here, the fiber diameter of the raw carbon fiber (B) means the number average fiber diameter, but most commercially available carbon fibers have a uniform fiber diameter, and if the fiber diameter is determined. A product with a substantially uniform fiber diameter can be obtained from commercial products.

  In the present invention, carbon fiber (B) to which a sizing agent is applied is used. Examples of the sizing agent include polyamide-based and olefin-based sizing agents. In the present invention, those using urethane-based or epoxy-based sizing agents are used. When carbon fiber (B) treated with a urethane-based or epoxy-based sizing agent is used, electromagnetic wave shielding properties are particularly improved. Among urethane-based or epoxy-based sizing agents, urethane-based ones are particularly preferable.

  The amount of the urethane-based or epoxy-based sizing agent is preferably 0.5 to 10% by mass based on the total of 100% by mass of the carbon fiber (B) and the urethane-based or epoxy-based sizing agent. If the amount is less than 0.5% by mass, the electromagnetic shielding property tends to deteriorate, more preferably 1% by mass or more, still more preferably 1.5% by mass or more, especially 2% by mass or more, particularly 2.5% by mass or more. It is preferably 8% by mass or less, more preferably 7% by mass or less, especially 6% by mass or less, especially 5% by mass or less, and particularly preferably 4% by mass or less.

  Content of carbon fiber (B) is 10-100 mass parts with respect to 100 mass parts of polycarbonate resin (A). If the amount is less than 10 parts by mass, the strength and electromagnetic wave shielding properties are insufficient, while if it exceeds 100 parts by mass, the impact resistance and fluidity are insufficient. The content of the carbon fiber (B) is preferably 13 parts by mass or more, more preferably 15 parts by mass or more, preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and further preferably 60 parts by mass or less. Among them, 50 parts by mass or less, particularly 40 parts by mass or less, and particularly 30 parts by mass or less are preferable.

[Flow modifier (C)]
The resin composition of the present invention preferably contains a flow modifier (C). The fluidity improver is a component that improves the fluidity of the polycarbonate resin, and various low-molecular compounds or high-molecular compounds can be used. Particularly preferred in the present invention is one or a combination of two or more selected from acrylonitonyl-styrene copolymer, polycarbonate oligomer and polycaprolactone.

  The acrylonitrile-styrene copolymer is a thermoplastic copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound. Here, examples of the vinyl cyanide compound include vinylcyan compounds such as acrylonitrile and methacrylonitrile, and acrylonitrile is particularly preferable. Examples of the aromatic vinyl compound include styrene and styrene derivatives such as styrene, α-methylstyrene, p-methylstyrene, vinylxylene, dimethylstyrene, pt-butylstyrene, bromostyrene, and dibromostyrene. Of these, styrene is preferred. In addition, these can also be used individually or in mixture of 2 or more types.

  As a preferable ratio of each of the structural units derived from the vinyl cyanide compound and the aromatic vinyl compound in the acrylonitrile-styrene copolymer, the structural unit derived from the vinyl cyanide compound is 10 to 40 when the total is 100% by mass. The structural unit derived from an aromatic vinyl compound is 90 to 60% by mass, more preferably 85 to 70% by mass, more preferably 15 to 30% by mass. Further, at the time of copolymerization, these vinyl compounds may be used by mixing with other vinyl compounds that can be copolymerized, and the mixing ratio of these other vinyl compounds in the acrylonitrile-styrene copolymer. The structural unit derived from the compound is preferably 15% by mass or less. Moreover, a well-known thing can be used for the initiator, chain transfer agent, etc. which are used by a copolymerization reaction as needed.

The acrylonitrile-styrene copolymer is produced by a method such as emulsion polymerization, solution polymerization, bulk polymerization, suspension polymerization or bulk / suspension polymerization, and any method may be used.
The melt flow rate (MFR) reflecting the molecular weight of the acrylonitrile-styrene copolymer is preferably 5 to 50 g / 10 min at 220 ° C. and a load of 10 kg, more preferably 10 to 30 g / 10 min.

  As the acrylonitrile-styrene copolymer, those commercially available as AS resins or SAN resins can be widely used.

  The polycarbonate oligomer is preferably 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3, It can be obtained by reaction of aromatic dihydric phenolic compounds typically exemplified by 5-dibromophenyl) propane with carbonate precursors represented by phosgene or transesterification reaction of aromatic dihydric phenol with diphenyl carbonate and the like. The aromatic dihydric phenol compounds may be used alone or in combination.

  The polycarbonate oligomer preferably has an average degree of polymerization of 2 to 15. If the average degree of polymerization of the polycarbonate oligomer is less than 2, it tends to be difficult to prevent bleeding out from the molded product at the time of molding, and if the average degree of polymerization exceeds 15, the appearance may be deteriorated. In the interfacial polymerization method using phosgene, the degree of polymerization of the polycarbonate oligomer may be adjusted by adding phenol and / or alkyl-substituted phenol to the polymerization system and blocking the ends.

Polycaprolactone is a polymer of caprolactone, particularly ε-caprolactone, that is, having a repeating unit of [—CH ₂ —CH ₂ —CH ₂ —CH ₂ —CH ₂ —CO—O—] in the polymer. It is a polymer or copolymer containing at least 70% by mass, preferably 75% by mass or more, and more preferably 80% by mass or more, of such a structural unit. When polycaprolactone is a copolymer of ε-caprolactone and other monomers, monomers that copolymerize with ε-caprolactone include lactone monomers such as β-propiolactone, pivalolactone, butyrolactone, ethylene oxide, Examples thereof include alkylene oxides such as 1,2-propion oxide, 1,3-propylene oxide and tetrahydrofuran, unsaturated monomers such as styrene, methyl methacrylate and butadiene, and coupling agents such as dimethyl terephthalate and diphenyl carbonate. These may be used alone or in combination of two or more. Part of the hydrogen atoms of the methylene chain of polycaprolactone may be substituted with a halogen atom or a hydrocarbon group, and the end of polycaprolactone may be terminated by esterification, etherification or the like. .

The number average molecular weight of the polycaprolactone is preferably 4000 to 50000, more preferably 5000 to 40000, and even more preferably 8000 to 30000 in terms of polystyrene-reduced number average molecular weight by gel permeation chromatography (GPC).
The production method of polycaprolactone is not particularly limited, and a method of ring-opening polymerization of ε-caprolactone using a suitable initiator such as alcohol, glycol, water, etc. and a catalyst such as titanium tetrabutoxide, tin chloride or the like is used.

  The content of the flow modifier (C) is preferably 1 to 25 parts by mass, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more with respect to 100 parts by mass of the polycarbonate resin (A). In addition, it is more preferably 20 parts by mass or less, and further preferably 18 parts by mass or less. If the content of the fluid modifier (C) is less than the above lower limit, it is difficult to sufficiently obtain the effect of improving the moldability and impact resistance due to the improvement of fluidity due to the incorporation of the fluid modifier (C). If the amount is larger than the above upper limit, heat resistance and impact resistance tend to be lowered, and appearance defects are liable to occur.

[Release agent]
The polycarbonate resin composition of the present invention preferably contains a release agent. Examples of the release agent include aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, polysiloxane silicone oils, and the like.

  Examples of the aliphatic carboxylic acid include saturated or unsaturated aliphatic monovalent, divalent or trivalent carboxylic acid. Here, the aliphatic carboxylic acid includes alicyclic carboxylic acid. Among these, preferable aliphatic carboxylic acids are monovalent or divalent carboxylic acids having 6 to 36 carbon atoms, and aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms are more preferable. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, mellicic acid, tetrariacontanoic acid, montanic acid, adipine Examples include acids and azelaic acid.

  As aliphatic carboxylic acid in ester of aliphatic carboxylic acid and alcohol, the same thing as the said aliphatic carboxylic acid can be used, for example. On the other hand, examples of the alcohol include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, monovalent or polyvalent saturated alcohols having 30 or less carbon atoms are preferable, and aliphatic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols having 30 or less carbon atoms are more preferable. In addition, an aliphatic includes an alicyclic compound here.

  Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol, and the like. Is mentioned.

  In addition, said ester may contain aliphatic carboxylic acid and / or alcohol as an impurity. Moreover, although said ester may be a pure substance, it may be a mixture of a plurality of compounds. Furthermore, the aliphatic carboxylic acid and alcohol which combine to form one ester may be used alone or in combination of two or more in any combination and ratio.

  Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture based on myricyl palmitate), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate Examples thereof include rate, glycerol distearate, glycerol tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate and the like.

  Examples of the aliphatic hydrocarbon having a number average molecular weight of 200 to 15,000 include liquid paraffin, paraffin wax, microwax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomer having 3 to 12 carbon atoms. Here, the aliphatic hydrocarbon includes alicyclic hydrocarbons. Further, these hydrocarbons may be partially oxidized. The number average molecular weight is preferably 5,000 or less. The aliphatic hydrocarbon may be a single substance, but even a mixture of various constituent components and molecular weights can be used as long as the main component is within the above range.

  Among these, paraffin wax, polyethylene wax, or a partial oxide of polyethylene wax is preferable, paraffin wax and polyethylene wax are more preferable, and polyethylene wax is particularly preferable.

In addition, 1 type may contain the mold release agent and 2 or more types may contain it by arbitrary combinations and a ratio.
The content of the release agent is usually 0.001 parts by mass or more, preferably 0.01 parts by mass or more, and usually 2 parts by mass or less, preferably 1 with respect to 100 parts by mass of the polycarbonate resin (A). It is below mass parts. When the content of the release agent is less than the lower limit of the above range, the effect of releasability may not be sufficient, and when the content of the release agent exceeds the upper limit of the above range, hydrolysis resistance And mold contamination during injection molding may occur.

[Carbon black]
The polycarbonate resin composition of the present invention preferably contains carbon black. There is no restriction | limiting in the kind, raw material seed | species, and manufacturing method as carbon black, Any of furnace black, channel black, acetylene black, ketjen black, etc. can be used. The number average particle diameter is not particularly limited, but is preferably about 5 to 60 nm. By containing carbon black having a number average particle diameter in such a range, it becomes easy to obtain a composition in which blisters hardly occur at high temperatures.

Nitrogen adsorption specific surface area of the carbon black ^{(unit: m} 2 / g) is preferably usually less than 1000 m ² / g, is preferably Among them 50 to 400 m ² / g. Setting the nitrogen adsorption specific surface area to less than 1000 m ² / g is preferable because the fluidity of the polycarbonate resin composition and the appearance of the molded product tend to be improved. The nitrogen adsorption specific surface area can be measured according to JIS K6217.

Further, the carbon black DBP (dibutyl phthalate) absorption ^is preferably less than 300 cm 3/100 g, is preferably Among them 30~200cm ³ / 100g. The DBP absorption amount by less than 300 cm ^3/100 g, tends to increase the appearance of fluidity and a molded article of the polycarbonate resin composition.
Incidentally, DBP absorption ^(unit: cm 3 / 100g) can be measured according to JIS K6217. The carbon black used in the present invention is not particularly limited with respect to its pH, but it is usually 2 to 10, preferably 3 to 9, and more preferably 4 to 8.

  Carbon black can be used alone or in combination of two or more. Furthermore, carbon black can be granulated using a binder, and can also be used in a masterbatch that is melt-kneaded at a high concentration in another resin. By using the melt-kneaded master batch, the handling property during extrusion and the dispersibility improvement in the resin composition can be achieved. Examples of the resin include polystyrene resin, polycarbonate resin, acrylic resin, and the like.

  The preferable content of carbon black is 0.5 to 5 parts by mass, more preferably 0.8 parts by mass or more, further preferably 1 part by mass or more, with respect to 100 parts by mass of the polycarbonate resin (A). Moreover, More preferably, it is 4 mass parts or less, More preferably, it is 3 mass parts or less.

[Other ingredients]
The polycarbonate resin composition of the present invention may contain other components other than the above, if necessary, as long as the desired physical properties are not significantly impaired. Examples of other components include resins other than polycarbonate resins and various resin additives other than those described above. In addition, 1 type may contain other components and 2 or more types may contain them by arbitrary combinations and ratios.

Other resins Examples of other resins include thermoplastic polyester resins such as polyethylene terephthalate resin, polytrimethylene terephthalate, polybutylene terephthalate resin; polystyrene resin, high impact polystyrene resin (HIPS), acrylonitrile-styrene-acrylic rubber Styrene resins such as polymers (ASA resins), acrylonitrile-ethylenepropylene rubber-styrene copolymers (AES resins), acrylonitrile-butadiene-styrene copolymers (ABS resins); polyolefin resins such as polyethylene resins and polypropylene resins Polyamide resin; polyimide resin; polyetherimide resin; polyurethane resin; polyphenylene ether resin; polyphenylene sulfide resin; It is.
In addition, 1 type may contain other resin and 2 or more types may contain it by arbitrary combinations and ratios.
When other resin is contained, it is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, in total 100 parts by mass of the polycarbonate resin (A) and other resins, and 20 parts by mass. More preferably, it is as follows.

Resin additives Examples of resin additives include flame retardants, anti-dripping agents, heat stabilizers, antioxidants, glass fibers, UV absorbers, dyes and pigments, antistatic agents, antifogging agents, lubricants, and antiblocking agents. , Plasticizers, dispersants, antibacterial agents and the like. In addition, 1 type may contain resin additive and 2 or more types may contain it by arbitrary combinations and a ratio.

[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, Polycarbonate resin (A) and carbon fiber (B), and it mix | blends as needed. Other components are mixed in advance using various mixers such as tumblers and Henschel mixers, and then melt-kneaded with a mixer such as a Banbury mixer, roll, brabender, single-screw kneading extruder, twin-screw kneading extruder, or kneader. The method of doing is mentioned. When using a twin-screw kneading extruder, the carbon fiber (B) is preferably side-fed.

The temperature for melt kneading is not particularly limited, but is preferably in the range of 240 to 320 ° C.
It is preferable that the ratio of the discharge amount of the extruder and the screw rotation number (screw rotation number / discharge amount) at the time of manufacturing by melt-kneading is 5 or less. By producing under such conditions, it becomes easy to set the mass average fiber length of carbon fibers in the obtained resin composition (pellet) in the range of 800 to 3000 μm, and the strength, rigidity, and impact resistance of the resin composition. In addition, the electromagnetic wave shielding property can be improved. The screw rotation speed / discharge amount is preferably 150 rpm / 100 kg / h or less, more preferably 120 rpm / 100 kg / h or less, and preferably 50 rpm / 20 kg / h or more.

  The polycarbonate resin composition of the present invention is characterized in that the carbon fibers in the resin composition have a mass average average fiber length of 800 to 3000 μm. By having such a fiber length dispersed in the resin composition, the fiber composition can have excellent strength, rigidity, impact resistance, and electromagnetic wave shielding properties. The mass average fiber length is preferably 1000 μm or more.

The polycarbonate resin composition of the present invention exhibits excellent strength, rigidity, impact resistance and electromagnetic shielding properties.
That is, as tensile properties measured in accordance with ISO standard 527-1 and ISO 527-2, the tensile strength is preferably 130 MPa or more, more preferably 140 MPa or more, and the tensile modulus is preferably 14000 MPa or more, more preferably. Indicates 15500 MPa or more.
Moreover, as a bending characteristic measured based on ISO standard 178, bending strength becomes like this. Preferably it is 180 MPa or more, More preferably, it is 210 MPa or more, and a bending elastic modulus becomes like this. Preferably it is 11500 MPa or more, More preferably, it shows 13000 MPa or more.
The Charpy impact strength measured according to ISO 179-1 and 2 is preferably 24 kJ / m ² or more, more preferably 30 kJ / m ² or more without notch, and preferably 5 kJ / with notch. m ² or more, more preferably 7 kJ / m ² or more.
Furthermore, the electromagnetic wave shielding property can show an excellent performance that the electromagnetic wave shielding effect (unit: dB) measured at 600 MHz in accordance with the KEC method is preferably −28 dB or less, more preferably −29 dB or less. It is.
Details of the measurement of each characteristic value described above are described in the examples.

[Molding]
The above-mentioned polycarbonate resin composition (pellet) is molded by various molding methods into a molded product.
The shape of the molded product is not particularly limited and can be appropriately selected according to the use and purpose of the molded product. For example, a plate shape, a plate shape, a rod shape, a sheet shape, a film shape, a cylindrical shape, an annular shape, Examples include a circular shape, an elliptical shape, a polygonal shape, an irregular shape, a hollow shape, a frame shape, a box shape, and a panel shape.

  The method for molding the molded body is not particularly limited, and a conventionally known molding method can be employed.For example, an injection molding method, an injection compression molding method, an extrusion molding method, a profile extrusion method, a transfer molding method, a hollow molding method, Gas assisted hollow molding method, blow molding method, extrusion blow molding, IMC (in-mold coating molding) molding method, rotational molding method, multilayer molding method, two-color molding method, insert molding method, sandwich molding method, foam molding method And a pressure molding method.

  The polycarbonate resin composition of the present invention has a high degree of electromagnetic shielding properties and is excellent in fluidity, strength, and rigidity. Therefore, it is used in various electronic and electrical equipment, OA equipment, transportation equipment such as automobiles, and various mechanical equipment fields. Can be suitably used. In particular, a molded product obtained by molding this is particularly suitable for a digital camera, a lens or various portable terminals, a housing such as a personal computer, a body, a housing, and the like.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily modified and implemented without departing from the gist of the present invention.
Each raw material component used in the following Examples and Comparative Examples is as shown in Table 1 below.

(Examples 1-12, Comparative Examples 1-4)
The components described in Table 1 above were blended in the proportions shown in Tables 2 and 3 below (all expressed in parts by mass) and mixed uniformly with a tumbler mixer, and then the most downstream part from the most upstream part C1. Using a mesh type co-rotating twin-screw extruder “TEM37BS” made by Toshiba Machine Co., Ltd., which has a cylinder configuration of part C12, feed from the barrel upstream of the extruder to the extruder, and the carbon fiber side feeds to the cylinder. Polycarbonate resin at a temperature of 300 ° C to 330 ° C, melt-kneaded by applying one of the following production amounts A, B, and C with the discharge amount and the rotational speed, extruded from a die into a strand, cooled with water, and cut. A pellet of the composition was obtained.
Production condition A: discharge amount 25 kg / hr, rotation speed: 70 rpm (rotation speed / discharge amount = 2.8)
Production condition B: discharge amount 60 kg / hr, rotation speed: 120 rpm (rotation speed / discharge amount = 2)
Production condition C: discharge amount 25 kg / hr, rotation speed: 200 rpm (rotation speed / discharge amount = 8)

[Evaluation of productivity]
The productivity in the process of manufacturing the above pellets was evaluated and judged according to the following criteria of ○ to X.
○: Strand breakage is extremely small and stable pelletizing is possible. △: Strand breakage occurs several times per minute, but can be handled with a mesh conveyor. Level: The state where the resin breaks at the moment the resin comes out of the die is 1 minute. Dozens of occurrences

[Measurement of Mass Average Fiber Length of Carbon Fiber in Composition Pellet]
About 1 gram of the resin composition pellet obtained above was dissolved in methylene chloride, filtered, and carbon fibers were isolated. The isolated carbon fibers were spread on a glass so as not to overlap as much as possible. The film was observed and photographed at a magnification of 12.5 with a “BX-50” manufactured by the company. About 3000 carbon fibers in the obtained photograph, the fiber length was measured, and it added and averaged and the mass average fiber length was calculated | required.

[Molding of ISO multipurpose specimen]
The pellets obtained above were dried at 100 ° C. for 5 hours, and then using an injection molding machine (“J55-60H” manufactured by Nippon Steel), cylinder set temperature 280-300 ° C., mold temperature 100 ° C., injection time 2 seconds. Then, injection molding was performed under the condition of a molding cycle of 40 seconds, and an ISO multipurpose test piece (4 mm thickness) was injection molded.

[Tensile properties]
Tensile strength (unit: MPa) and tensile elastic modulus (unit: MPa) were measured using the ISO test piece (4 mm) in accordance with ISO standards 527-1 and ISO527-2.

[Bending characteristics]
Based on ISO178, the bending strength (unit: MPa) and the bending elastic modulus (unit: MPa) were measured at 23 ° C. using the ISO test piece (4 mm).

[Charpy impact strength]
The pellets obtained above were converted into ISO 179-1, 2 using an injection molding machine (“SG75MII” manufactured by Sumitomo Heavy Industries, Ltd.) under the conditions of a cylinder temperature of 280 ° C., a mold temperature of 80 ° C., and a molding cycle of 45 seconds. A 4 mm thick impact resistance test piece was prepared, and Charpy impact strength (kJ / m ² ) was measured at a temperature of 23 ° C. for the unnotched and notched test pieces.

[Electromagnetic shielding]
After the pellets obtained above were dried at 100 ° C. for 5 hours, the cylinder setting temperature was 320 ° C., the mold temperature was 120 ° C., and the injection speed was 1.6 seconds with an injection molding machine (“J180AD” manufactured by Nippon Steel). Injection molding was performed under the conditions to obtain a flat test piece having a thickness of 100 mm × 150 mm × 2 mm.
About the obtained test piece, the electromagnetic wave shielding effect (unit: dB) in 600 MHz was measured with the electromagnetic wave shielding property measuring apparatus based on KEC (Kansai Electronics Industry Promotion Center) method.

[Surface roughness]
About the flat test piece obtained above, using a surface roughness shape measuring instrument ("Laser Microscope VK-X100" manufactured by KEYENCE, wavelength 658 nm red laser, output 0.95 mW, pulse width 1 ns) at 400 times. The surface roughness (arithmetic mean roughness: Ra) was measured.
The above evaluation results are shown in Table 2 and Table 3 below.

  The polycarbonate resin composition of the present invention has high electromagnetic shielding properties and excellent fluidity, strength, and rigidity. Therefore, various electronic and electrical equipment, precision equipment, OA equipment, transportation equipment such as automobiles, and various mechanical equipment. It is particularly suitable for digital cameras or various portable terminals, housings such as personal computers, bodies, housings, etc., and has very high industrial applicability.

Claims (7)

  A polycarbonate resin composition containing 10 to 100 parts by mass of carbon fiber (B) with respect to 100 parts by mass of polycarbonate resin (A), and treated with a polyurethane-based or epoxy-based sizing agent as carbon fiber (B). A polycarbonate resin composition produced by melt-kneading carbon fibers having a length of 1 to 8 mm as a raw material, and having a mass average fiber length of carbon fibers in the resin composition in the range of 800 to 3000 μm.   Furthermore, the polycarbonate resin composition of Claim 1 which contains 1-25 mass parts of flow modifiers (C) with respect to 100 mass parts of polycarbonate resin (A).   The polycarbonate resin composition according to claim 2, wherein the flow modifier (C) is selected from an acrylonitonyl-styrene copolymer, a polycarbonate oligomer, and polycaprolactone.   The polycarbonate resin composition according to claim 1, wherein the carbon fiber (B) raw material has a fiber diameter of 3 to 10 μm.   The polycarbonate resin composition according to claim 1, wherein the content of the polyurethane-based or epoxy-based sizing agent is 1 to 10 parts by mass based on a total of 100% by mass of the carbon fiber (B) and the sizing agent.   The polycarbonate resin composition according to claim 1, wherein the ratio of the discharge amount of the extruder and the screw rotation number (screw rotation number / discharge amount) at the time of manufacturing by melt-kneading is 5 or less.   The molded article formed by shape | molding the polycarbonate resin composition of any one of Claims 1-6.