JP2012219227A - Electroconductive thermoplastic resin composition and molded article thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroconductive thermoplastic resin composition which has excellent physical property balance and can be given excellent electroconductivity with a small amount of electroconductive substance and to provide a molded article thereof.SOLUTION: The electroconductive thermoplastic resin composition comprises a rubber-reinforced styrenic resin (A), a metal coated organic fiber (B) and a copolymer (C) having an epoxy group or an unsaturated carboxylic acid group, wherein 3 to 15 pts.wt. of metal coated organic fiber (B) and 1 to 20 pts.wt. of copolymer (C) are included in 100 pts.wt. of the electroconductive thermoplastic resin composition.

Description

  The present invention relates to a conductive thermoplastic resin composition having not only excellent physical property balance but also metal-coated organic fibers and excellent conductivity, and a molded product thereof.

  Conventionally, a conductive thermoplastic resin composition in which a conductive filler is mixed with a resin serving as a base has been manufactured. As the conductive filler, powder or fiber made of a conductive compound such as a conductive metal, an alloy thereof, or a metal oxide is used. These are widely used in IC trays, personal computers, liquid crystal panels, etc. where electromagnetic shielding and anti-static properties are required because the substrate is conductive, and the effects of electromagnetic waves and magnetic fields on the human body due to the recent health orientation. In recent years, it has come to be used frequently.

  In the case of producing a plastic molded article having conductivity, a resin composition such as a pellet containing a thermoplastic resin and metal-coated fibers is used. As the fiber used as the conductive thermoplastic resin composition, stainless fiber, carbon fiber, metal-coated glass fiber, metal-coated carbon fiber, copper fiber coated with solder, and the like are used. Among these, stainless steel fibers, carbon fibers, and metal-coated carbon fibers are common.

  Although the metal-coated carbon fiber has excellent conductive properties, in order to have the required conductive properties because the fiber breaks during the molding process, the content in the total amount of the molded product is 15-30. Since the weight percent is also necessary, the amount added may increase, and the mechanical properties of the resin composition may decrease or the moldability may decrease.

  In recent years, metal-coated organic fibers have been developed as new materials that impart conductivity. Organic fibers are preferably used as they are less likely to break during melt-kneading than the above fibers. This metal-coated organic fiber is impregnated with a thermoplastic resin in a state where the fibers are aligned in one direction, and is particularly used as a material for an injection molded product.

  For example, in Patent Document 1, para-aramid fibers are plated with gold, silver, copper, tin, aluminum, or an alloy thereof, and metal-coated organic fibers cut to a length of 2 to 30 mm are knitted, woven, or A technique for making a nonwoven fabric by making paper, impregnating it with a resin, and forming a molded plate by hot pressing is disclosed. However, in this molding method, only simple shapes such as a plate shape and a curved surface shape can be created, and a complicated shape such as that obtained by injection molding cannot be created. Therefore, it has been difficult to develop a molded product in an electronic-related molded casing such as an OA device or an optical electronic device or a precise box-shaped component.

  In Patent Document 2, in a resin composition in which metal-coated organic fibers are mixed with a resin so as to have conductivity, in order to increase the adhesion strength between the metal surface coated on the substrate fiber and the contact surface of the substrate fiber, This is a technique characterized in that heat treatment is performed at a temperature higher than the fiber crystallization temperature and lower than the melting temperature. However, even when the metal-coated organic fiber is heat-treated at a temperature higher than the crystallization temperature of the substrate fiber and lower than the melting temperature, the adhesion strength between the coated metal and the substrate fiber surface is insufficient, and the metal-coated organic fiber is used as a resin. When mixing and injection molding, it becomes difficult to withstand the shearing force received by the barrel and screw rotation of the molding machine, and the metal coating film peels off from the base fiber, making it difficult to develop conductivity. In addition, there is a problem that the variation between the molded products is large.

  Therefore, Patent Document 3 has recently proposed that a metal-coated organic fiber or fiber bundle is impregnated with a thermoplastic resin to form a pellet, which is used as a master batch. Specifically, for example, there is a method in which the surface of aramid fiber is coated with a metal such as copper, impregnated with a thermoplastic resin, and used as pellets having a length of 6 mm, thereby improving moldability and enhancing conductive properties. It is used.

  However, even in this case, when melt kneading is performed using a single-screw or twin-screw extruder, peeling of the coated metal and breakage of the metal-coated organic fiber may occur due to the shearing force of the screw mixing element. Fiber breakage was inevitable, and its uniform dispersibility still had difficulties, and there was a limitation in improving conductivity. Therefore, a conductive thermoplastic resin composition that can suppress breakage of metal-coated organic fibers in melt kneading has been desired.

JP 2003-152389 A

JP 2002-358826 A

JP-A-2005-290086

  An object of the present invention is to provide a conductive thermoplastic resin composition and a molded product thereof, which are excellent in balance of physical properties and can provide excellent conductivity by using a small amount of a conductive substance. .

  As a result of intensive studies to solve such problems, the present inventors have used single-screw and twin-screw extruders by using a copolymer containing an epoxy group or an unsaturated carboxylic acid group together with a metal-coated organic fiber. When melt kneading was performed, it was found that peeling of the coated metal and breakage of the metal-coated organic fiber could be suppressed by the shearing force of the screw mixing element, and the present invention was achieved.

  That is, the present invention relates to a conductive thermoplastic resin composition comprising a rubber-reinforced styrene resin (A), a metal-coated organic fiber (B), and a copolymer (C) having an epoxy group or an unsaturated carboxylic acid group. The metal-coated organic fiber (B) is contained in 3 to 15 parts by weight and the copolymer (C) is contained in 1 to 20 parts by weight in 100 parts by weight of the conductive thermoplastic resin composition. The present invention relates to a conductive thermoplastic resin composition, and a molded product obtained by molding the resin composition.

  According to the present invention, it is possible to provide a conductive thermoplastic resin composition and a molded product thereof, which are excellent in physical property balance and can provide excellent conductivity by using a small amount of a conductive substance.

Hereinafter, the present invention will be described in detail.
The conductive thermoplastic resin composition of the present invention comprises a rubber-reinforced styrene resin (A), a metal-coated organic fiber (B), and a copolymer (C) having an epoxy group or an unsaturated carboxylic acid group. A conductive thermoplastic resin composition, comprising 3 to 15 parts by weight of a metal-coated organic fiber (B) and 1 to 20 parts by weight of a copolymer (C) in 100 parts by weight of the conductive thermoplastic resin composition It is included.

-Rubber reinforced styrene resin (A)-
The rubber-reinforced styrene resin (A) used in the present invention is an aromatic vinyl monomer, vinyl cyanide monomer, (meth) acrylic acid ester monomer in the presence of a rubbery polymer. Selected from the group consisting of a polymer and other copolymerizable monomers, a graft copolymer obtained by graft polymerization of at least one monomer, or the graft copolymer and the above monomer It is a resin composition composed of a (co) polymer obtained by (co) polymerization.

  The rubber-like polymer used in the rubber-reinforced styrene resin (A) used in the present invention is not particularly limited, but polybutadiene rubber, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), etc. Diene rubber, ethylene-propylene rubber, ethylene-propylene-nonconjugated diene (ethylidene norbornene, dicyclopentadiene, etc.) rubber such as ethylene-propylene rubber, polybutyl acrylate, etc. acrylic rubber, silicone rubber, and more One or more composite rubbers selected from these rubbers can be used, and one or two or more can be used. In particular, polybutadiene rubber, styrene-butadiene rubber, butyl acrylate rubber, ethylene-propylene-diene rubber, and silicone rubber are preferable.

  The weight average particle diameter of the rubbery polymer used in the rubber-reinforced styrene resin (A) is preferably 0.05 to 2.0 μm, more preferably 0.1 to 1.0 μm, from the viewpoint of physical property balance. .

  Examples of the aromatic vinyl monomer used in the rubber-reinforced styrene resin (A) include styrene, α-methylstyrene, paramethylstyrene, chlorostyrene, bromostyrene, and the like. it can. In particular, styrene and α-methylstyrene are preferable.

  Examples of the vinyl cyanide monomer used in the rubber-reinforced styrene resin (A) include acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile and the like, and one or more of them can be used. Particularly preferred is acrylonitrile.

  (Meth) acrylate monomers used in rubber-reinforced styrene resins (A) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. , 2-ethylhexyl acrylate, phenyl (meth) acrylate, 4-t-butylphenyl (meth) acrylate, (di) bromophenyl (meth) acrylate, chlorophenyl (meth) acrylate, etc. Or it can use 2 or more types.

  Examples of other copolymerizable vinyl monomers used in the rubber-reinforced styrene resin (A) include maleimide monomers (for example, N-phenylmaleimide, N-cyclohexylmaleimide, etc.), and amide monomers. (For example, acrylamide, methacrylamide, etc.) can be used, and each can be used alone or in combination of two or more (excluding monomers having an epoxy group or an unsaturated carboxylic acid group) .

  Although there is no restriction | limiting in particular in the composition ratio of said vinyl-type monomer graft-polymerized with a rubber-like polymer, Aromatic vinyl-type monomer 60-90 weight% and vinyl cyanide-type monomer 10-40 Composition ratio of 30% by weight, composition ratio of 30 to 80% by weight of aromatic vinyl monomer and 20 to 70% by weight of (meth) acrylate monomer, 20 to 70% by weight of aromatic vinyl monomer And a composition ratio of 20 to 70% by weight of a (meth) acrylic acid ester monomer and 10 to 60% by weight of a vinyl cyanide monomer.

  The (co) polymer used together with the graft copolymer is a (co) polymer obtained by (co) polymerizing a vinyl monomer used for graft polymerization. Although there is no restriction | limiting in particular in the composition ratio of the monomer used for a (co) polymer, The composition ratio of aromatic vinyl-type monomer 60 to 90 weight% and vinyl cyanide-type monomer 10 to 40 weight%, Composition ratio of 30 to 70% by weight of aromatic vinyl monomer and 30 to 70% by weight of (meth) acrylic acid ester monomer, 25 to 70% by weight of aromatic vinyl monomer and (meth) acrylic acid Composition ratio of ester monomer 25 to 70% by weight, vinyl cyanide monomer 5 to 50% by weight, and aromatic vinyl monomer 60 to 100% by weight and other copolymerizable vinyl monomers A composition ratio of 0 to 40% by weight of the monomer is preferable from the viewpoint of balance of physical properties. Further, the (co) polymer of the present invention may be used by appropriately combining a plurality of (co) polymers having different composition ratios according to the purpose.

  There is no particular limitation on the composition ratio between the rubber-like polymer component and the monomer component (vinyl monomer component used for polymerization) in the rubber-reinforced styrene resin (A), but from the viewpoint of balance of physical properties. Therefore, the rubbery polymer component is preferably 3 to 80% by weight and the monomer component is 97 to 20% by weight. The content of the rubber-like polymer in the rubber-reinforced styrene resin (A) is the ratio of the rubber-like polymer and the monomer component at the time of producing the graft copolymer, or the graft copolymer and (co) weight. It is possible by changing the blending ratio of the coalesced as appropriate.

  The graft copolymer and (co) polymer constituting the rubber-reinforced styrene resin (A) are conventionally known polymerization methods such as emulsion polymerization method, suspension polymerization method, bulk polymerization method, solution polymerization method and the like. It can be manufactured by a combination of

-Metal-coated organic fiber (B)-
The metal-coated organic fiber (B) used in the present invention is an organic fiber coated with a metal.
Examples of organic fibers constituting the metal-coated organic fiber (B) include carbon fibers, meta-aramid fibers, para-aramid fibers, and the like, which are generated during melt-kneading in single-screw and twin-screw extruders. From the viewpoint of suppressing breakage due to the shearing force of the screw, it is preferable to use a meta-aramid fiber.

  As a metal which coat | covers an organic fiber as a metal covering organic fiber (B), gold | metal | money, silver, copper, tin, aluminum, or these alloys are mentioned, One or more types chosen from these can be used. In particular, gold and silver are preferable from the viewpoint of good conductivity, resistance to oxidation, and excellent malleability, and copper is preferable from the viewpoint of cost. The amount of metal coating is appropriately determined depending on the type of fiber used, the type of metal, and the required volume resistivity, but it is preferable to coat the fiber surface with a thickness of 0.1 to 1.0 μm.

  The method for coating the metal onto the organic fiber is not particularly limited, but a known electroless plating method is common. Other methods such as vacuum vapor deposition and sputtering are also possible.

  The length of the metal-coated organic fiber (B) is preferably 3 to 8 mm. If the length of the metal-coated organic fiber (B) is less than 3 mm, the conductive performance may be insufficiently exhibited. If the length of the metal-coated organic fiber (B) exceeds 8 mm, the metal-coated organic fiber is likely to be clogged at the injection port during injection molding. The fiber diameter of the metal-coated organic fiber (B) is not particularly limited, but the fiber diameter per fiber is preferably in the range of 6 to 20 μm from the viewpoint of handling.

  The conductive thermoplastic resin composition of the present invention can be obtained by melt-kneading the metal-coated organic fiber (B) together with the rubber-reinforced styrene resin (A), and when these are melt-mixed with an extruder or the like, From the viewpoint of dispersibility and handleability of the metal-coated organic fiber (B), the metal-coated organic fiber (B) is preferably used as a master batch impregnated or coated with a thermoplastic resin.

  There is no particular limitation on the thermoplastic resin used in the metal-coated organic fiber masterbatch, but from the viewpoint of compatibility with the rubber-reinforced styrene resin, at least these among polyamide resin, polyethylene terephthalate resin, polycarbonate resin, and ABS resin Among them, it is preferable to use one or more of them, and it is more preferable to use a polyethylene terephthalate resin from the viewpoint of processability to a masterbatch.

  The method for impregnating the metal-coated organic fiber (B) with the thermoplastic resin is not limited, but as a condition for satisfactorily impregnating the metal-coated organic fiber (B), it is specified in JIS K6862 under the temperature condition at the time of impregnation. The value of the melt viscosity of the thermoplastic resin measured by the measured method is preferably 4000 mPa · s or less. Moreover, there is no restriction | limiting in particular in the method of coating a thermoplastic resin to a metal covering organic fiber (B), A well-known technique can be used.

  Metal-coated organic fiber (B) is made into a masterbatch by impregnation or coating with thermoplastic resin, making the bundle of fibers compact and easy to handle, and good fiber dispersion when formed into a molded product Can be made. Also, by impregnating or coating the resin, the fiber is wet with the resin, so that there is no air in the fiber. By producing a molded product using the fiber in this state, bubbles are formed. It becomes difficult to enter, and the mechanical properties and appearance are likely to be good.

  The amount of the metal-coated organic fiber contained in the metal-coated organic fiber master batch is preferably 30 to 70 parts by weight in 100 parts by weight of the master batch from the viewpoint of handleability as a master batch.

  The conductive thermoplastic resin composition of the present invention needs to contain 3 to 15 parts by weight of metal-coated organic fibers in 100 weights of the composition. If the amount is less than 3 parts by weight, the necessary conductivity cannot be obtained. If the amount exceeds 15 parts by weight, not only is the cost increased, but the physical properties of the resin composition deteriorate. The content is preferably 4 to 12 parts by weight, and more preferably 5 to 10 parts by weight.

-Copolymer (C)-
The copolymer (C) used in the present invention is a copolymer containing an epoxy group or an unsaturated carboxylic acid group, and is a phase that enhances the compatibility between the rubber-reinforced styrene resin and the metal-coated organic fiber masterbatch. Has a role as a solubilizer.

  Examples of the epoxy group-containing copolymer include a copolymer of an unsaturated epoxy compound and an olefin or an ethylene-based unsaturated compound, and a copolymer of the unsaturated epoxy compound and the olefin and, if necessary, an ethylenically-unsaturated compound. Polymerization, graft copolymerization of an unsaturated compound in the presence of a copolymer of an unsaturated epoxy compound in the presence of an olefin polymer or a copolymer of an olefin and an ethylenically unsaturated compound, It can be produced by graft copolymerizing an unsaturated epoxy compound in the presence of a copolymer of an olefin and an ethylenically unsaturated compound.

  Examples of the unsaturated epoxy compound used in the epoxy group-containing copolymer include unsaturated glycidyl esters, unsaturated glycidyl ethers, epoxy ethers, and P-glycidyl styrenes. Specifically, glycidyl acrylate, glycidyl methacrylate, itaconic acid glycidyl esters, butenecarboxylic acid esters, allyl glycidyl ether, 2-methylallyl glycidyl ether, styrene-P-glycidyl ether, 3,4-epoxybutene, 3,4 -Epoxy-3-methyl-1-butene, 3,4-epoxy-1-pentene, 3,4-epoxy-3-methylpentene, 5,6-epoxy-1-hexene, vinylcyclohexene monoxide, P-glycidyl Styrene etc. are mentioned, 1 type, or 2 or more types can be used. Particularly preferred is glycidyl acrylate or glycidyl methacrylate.

  Examples of the olefin used in the epoxy group-containing copolymer include ethylene, propylene, butene, pentene, and the like, and one or more of them can be used. In particular, ethylene and propylene are preferable.

Examples of the ethylenically unsaturated compound used in the epoxy group-containing copolymer include vinyl esters containing C _{2 to} C ₅ in the saturated carboxylic acid component, acrylic acid and methacrylic acid containing C _{1 to} C ₈ in the saturated alcohol component. Examples thereof include esters, maleic esters, and halogenated vinyls.

  Preferable examples of the epoxy group-containing copolymer include ethylene-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer, ethylene-methacrylate-glycidyl methacrylate copolymer, and polyethylene, polypropylene, poly-1- Examples include copolymers obtained by grafting glycidyl methacrylate in the presence of olefin polymers such as butene, poly-4-methyl-pentene-1, and ethylene-propylene-diene copolymers.

  Examples of unsaturated carboxylic acid group-containing copolymers include unsaturated carboxylic acid monomers, aromatic vinyl monomers, vinyl cyanide monomers, (meth) acrylic acid ester monomers, and others. And a copolymer obtained by polymerizing at least one monomer selected from the group consisting of the copolymerizable monomers, known emulsion polymerization method, bulk polymerization method, suspension polymerization method It can be produced by a solution polymerization method.

  Examples of the unsaturated carboxylic acid monomer constituting the unsaturated carboxylic acid group-containing copolymer include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and the like. it can. In particular, methacrylic acid is preferred.

  From aromatic vinyl monomer, vinyl cyanide monomer, (meth) acrylic acid ester monomer and other copolymerizable monomers constituting the unsaturated carboxylic acid group-containing copolymer As the at least one monomer selected from the group constituted, the same ones as the respective monomers described as examples in the rubber-reinforced styrene resin can be used.

  Although there is no restriction | limiting in particular about the reduced viscosity of an unsaturated carboxylic acid group containing copolymer, It is preferable that it is 0.2-1.2 dl / g. The reduced viscosity can be appropriately adjusted depending on the polymerization temperature, the monomer addition method, the initiator used, and the type and amount of a polymerization chain transfer agent such as t-dodecyl mercaptan.

  In the conductive thermoplastic resin composition of the present invention, it is necessary that 1 to 20 parts by weight of the copolymer (C) is contained in 100 parts by weight of the composition. If the amount is less than 1 part by weight, the compatibility between the rubber-reinforced styrene resin and the metal-coated organic fiber masterbatch is insufficient, and the breakage of the metal-coated organic fiber cannot be reduced, resulting in a reduction in volume resistivity. I can't. Moreover, when it exceeds 20 weight part, the problem that the physical property of a resin composition falls will arise. The content is preferably 3 to 17 parts by weight, and more preferably 5 to 15 parts by weight.

  The mixing method of each component in the present invention is not particularly limited, and the mixture of these constituent components can be used as an extruder such as a single screw extruder or a twin screw extruder, a Banbury mixer, a kneader / louder, a pressure kneader, a heating roll, etc. Can be mixed.

  The conductive thermoplastic resin composition of the present invention can be used by mixing other thermoplastic resins together with the rubber-reinforced styrene-based resin within a range not to impair the purpose. As such other thermoplastic resins, for example, acrylic resins such as polycarbonate resin and polymethyl methacrylate, polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin, polylactic acid resin and the like can be used.

  In addition, the conductive thermoplastic resin composition of the present invention includes hindered phenol-based, sulfur-containing organic compound-based, phosphorus-containing organic compound-based antioxidants, phenol-based, acrylate-based, etc. within a range that does not impair the purpose. Heat stabilizers, benzotriazole, benzophenone, salicylate UV absorbers, organic nickel, lubricants such as higher fatty acid amides, plasticizers such as phosphate esters, polybromophenyl ether, tetrabromobisphenol-A Add flame retardants and flame retardants such as brominated epoxy oligomers, brominated halogenated compounds, phosphorus compounds, antimony trioxide, odor masking agents, carbon black, titanium oxide, pigments, dyes, etc. You can also. Furthermore, reinforcing agents and fillers such as talc, calcium carbonate, aluminum hydroxide, glass fiber, glass flake, glass bead, carbon fiber, and metal fiber can be added.

  In order to describe the present invention more specifically, examples and comparative examples will be described below, but these do not limit the present invention. In the examples, “parts” and “%” are based on weight.

-Rubber reinforced styrene resin (A)-
ABS resin (Nippon A & L Co., Ltd. Clarastic GA-501)

-Metal-coated organic fiber (B)-
A masterbatch (A6G-1A2 manufactured by Daiwabo Neu Co., Ltd.) having an aramid fiber coated with copper and impregnated with polyethylene terephthalate resin and containing 50% by weight of metal-coated organic fiber.

-Copolymer (C)-
(C-1): Ethylene-glycidyl methacrylate-vinyl acetate copolymer (Sumitomo Chemical Co., Ltd. Bond Fast-2B)
(C-2): methacrylic acid-styrene-acrylonitrile copolymer After adding 100 parts by weight of deionized water to a nitrogen-replaced glass reactor, the temperature was raised, and when the temperature reached 60 ° C., potassium persulfate 0 .3 parts, 5 parts of methacrylic acid, 70 parts of styrene, 25 parts of acrylonitrile, 6% of a monomer mixed solution consisting of 1.6 parts of terrestrial decyl mercaptan and 1 part of sodium dodecylbenzenesulfonate were dissolved in 20 parts of deionized water. 10% aqueous emulsifier solution was added. Thereafter, the temperature was raised to 65 ° C., and the remaining monomer mixture and aqueous emulsifier solution were continuously added. Thereafter, the temperature was raised to 70 ° C. to complete the polymerization. After salting out using calcium chloride, dehydration and drying were performed to obtain a methacrylic acid-styrene-acrylonitrile copolymer (C-2).

  After mixing the rubber-reinforced styrene-based resin (A), metal-coated organic fiber masterbatch (B), and copolymer (C) having the composition ratio shown in Table 1, "NVC-50 Extruder" manufactured by OH Machinery Co., Ltd. The conductive thermoplastic resin composition was obtained by melt-kneading and pelletizing at 160 ° C. and a screw rotation speed: 200 rpm using a single screw extruder.

<Test example>
The pellets obtained in each Example and Comparative Example were used for the following evaluation. The results are shown in Table 1.

-Impact resistance-
Using the obtained pellets, test pieces were molded according to ISO test method 294, and impact resistance was measured. The impact resistance was in conformity with ISO 179, and a Charpy impact value with a notch was measured at a thickness of 4 mm. Unit: kJ / m ²

-Fluidity-
Using the obtained pellets, melt volume flow rate was measured according to ISO1133. Unit; ^cm 3/10 minutes

  The obtained pellets are put into an injection molding machine of “SAV-100” manufactured by Yamashiro Seiki, and are molded under the conditions of cylinder temperature: 235 ° C. and mold temperature: 60 ° C., thereby obtaining a plate of 60 mm × 60 mm × 2 mm. A shaped molded product was produced. The obtained molded product was processed using a cutter to produce a 50 mm × 60 mm × 2 mm test plate.

-Volume resistivity-
A conductive paste was applied to both sides of the end face of 2 mm × 50 mm of the test plate and dried.
Conductive paste: Silver (ELECTRONDUCTIVE dotite: manufactured by Fujikura Kasei Co., Ltd.)
Using a digital multimeter, the electrical resistance was measured from both sides where the conductive paste was applied, and the volume resistivity was calculated using the following formula.
Measuring instrument: Digital multimeter (73303: Yokogawa M & C Co., Ltd.)
Volume resistivity δ (Ω · cm) = R × S / L (R: measured electric resistance (Ω), S: cross-sectional area of test piece (cm ² ), L: length between electrodes (cm))

  As shown in Table 1, it can be seen that the conductive thermoplastic resin composition of the present invention is excellent in conductivity while maintaining a balance of physical properties.

  As shown in Table 1, Comparative Example 1 not using the copolymer (C) was inferior in volume resistivity. Further, Comparative Examples 2 and 3 in which the content of the copolymer (C) was less than 1 part by weight were inferior in volume resistivity. Comparative Examples 4 and 5 in which the content of the copolymer (C) exceeded 20 parts by weight were excellent in volume resistivity but inferior in impact resistance. Comparative Example 6 in which the content of the metal-coated organic fiber was less than 3 parts by weight was excellent in physical property balance but inferior in volume resistivity. Comparative Example 7 in which the content of the metal-coated organic fiber exceeded 15 parts by weight was excellent in volume resistivity but inferior in physical property balance.

  As described above, the conductive thermoplastic resin composition of the present invention is excellent in physical property balance and electrical conductivity, and has high utility value as an electronic device component casing and automotive component.

Claims (3)

  A conductive thermoplastic resin composition comprising a rubber-reinforced styrene resin (A), a metal-coated organic fiber (B), and a copolymer (C) having an epoxy group or an unsaturated carboxylic acid group, Conductive thermoplastic resin composition comprising 3 to 15 parts by weight of metal-coated organic fiber (B) and 1 to 20 parts by weight of copolymer (C) in 100 parts by weight of a thermoplastic resin composition object.   A masterbatch obtained by impregnating or coating a metal-coated organic fiber (B) with a thermoplastic resin as the metal-coated organic fiber (B), and the content of the metal-coated organic fiber is 30 to 70 parts by weight in 100 parts by weight of the masterbatch The conductive thermoplastic resin composition according to claim 1, which is contained.   A molded article obtained by molding the conductive thermoplastic resin composition according to claim 1.