JP5629916B2 - Fiber / resin composite composition pellet for electromagnetic shielding, resin composition for electromagnetic shielding, and molded article thereof - Google Patents

Description

  The present invention relates to an electromagnetic shielding fiber / resin composite composition pellet obtained by impregnating a long fiber bundle of conductive fibers with a polycarbonate resin, and an electromagnetic shielding resin composition comprising the electromagnetic shielding fiber / resin composite composition pellet. In addition, the present invention relates to a resin molded body for electromagnetic wave shielding formed by molding the resin composition for electromagnetic wave shielding.

When producing a plastic molded article imparted with electromagnetic wave shielding performance, a pellet-like fiber / resin composite composition containing a thermoplastic resin and conductive fibers is used. In this fiber / resin composite composition, the conductive fiber is impregnated with a thermoplastic resin in a state in which long fibers are aligned in one direction, and is evaluated as a material for an injection molded product having electromagnetic wave shielding performance. As the conductive fiber, stainless steel fiber, carbon fiber, metal-coated glass fiber, metal-coated carbon fiber, metal-coated organic fiber, copper-coated solder, etc. are used, but the most common among these These include stainless steel fibers and carbon fibers, metal coated carbon fibers, and metal coated organic fibers.
Molded articles made of an electromagnetic shielding resin composition using these conductive fibers have excellent performance.

  For example, in a molded product using stainless steel fibers, a stainless steel fiber / resin composite pellet impregnated with a thermoplastic resin is used, and after mixing with a thermoplastic resin so that the fiber content is about 8 to 15% by weight, the injection is performed. If molded, the electromagnetic shielding performance can be expressed. Moreover, since the specific gravity of stainless steel is as large as about 8 and the volume fraction of stainless steel in a molded product having such a fiber content is about 1 to 2% or more, mechanical properties are not greatly impaired.

  In the case of carbon fiber, since electromagnetic shielding performance can be imparted to a molded product with a content of about 15 to 40% by weight, the rigidity is increased in mechanical properties, and the shrinkage rate after molding is Since it is low, the dimensional accuracy is high.

  In the metal-coated carbon fiber, the electromagnetic shielding performance can be imparted to the molded product with a content of about 10 to 30% by weight less than the carbon fiber, and the mechanical properties are rigid as in the case of the carbon fiber. In addition, since the shrinkage rate after molding is low, the dimensional accuracy is high.

  In the metal-coated organic fiber, since the fiber itself is easily deformed, the fiber is not easily broken in the molding process, and the fiber length can be kept long. For this reason, electromagnetic wave shielding performance can be imparted to the molded article with a content of about 3 to 20% by weight. Moreover, since the specific gravity is also small compared with carbon fiber, it is possible to reduce the weight of a molded article.

Examples of resins impregnated in these conductive fibers include styrene resin, polyamide resin (PA resin), polycarbonate resin, polyester resin, polyolefin resin, and polyphenylene sulfide resin in Patent Document 1. The number average molecular weight of about 17,000 to 32,000 is desirable for the polycarbonate resin, but only ABS resin and PA / ABS resin are used in the examples. In the example of Patent Document 2, a thermoplastic polyester resin is used, and in the example of Patent Document 3, a polymerized fatty acid polyamide resin is used.
As described above, various resins have been conventionally described for the resin impregnated in the fiber, but in reality, ABS resin, PA resin, and polyester resin have been used as the resin impregnated in the fiber. .

However, when a polycarbonate resin is used as a thermoplastic resin to produce a molded product with electromagnetic wave shielding performance, a polyamide resin such as PA resin or an alloy (PA / ABS resin) of this resin and ABS resin is electrically conductive. When used as an impregnating resin for a conductive fiber, the polyamide-based resin has a problem of decomposing a polycarbonate resin. Furthermore, if a polyester-based resin is used as the fiber-impregnated resin, the polyester-based resin and the polycarbonate resin are heated for a long time in two steps of the extrusion process and the molding process, thereby causing a transesterification reaction and reducing heat resistance. Had a problem.
In addition, when ABS resin is used as a fiber-impregnated resin, when the pellet of the fiber / resin composite composition is formed by the drawing method due to insufficient strength of the ABS resin, the resin breaks, and the fiber / resin composite pellet is produced. When it is difficult or flame retardancy or heat resistance is required, there is a problem that the ABS resin deteriorates the flame retardancy of the polycarbonate resin or lowers the heat resistance.

  As the fiber-impregnated resin, it is possible to use, for example, a polycarbonate resin without using a resin that deteriorates the polycarbonate resin. However, in the polycarbonate resin having a molecular weight of about 17,000 to 32,000 suggested in Patent Document 1, Since the viscosity is too high when impregnated, it is very difficult to sufficiently impregnate the polycarbonate resin in the fiber, and the defect rate that the fiber bundle falls out of the impregnating resin becomes high. / Production of resin composite composition was difficult.

JP 2004-014990 A Japanese Patent No. 2738164 JP 2003-160673 A

The present invention solves the above-described conventional problems, uses a polycarbonate resin as a fiber-impregnated resin, and can easily and sufficiently impregnate a long fiber bundle of conductive fibers with a polycarbonate resin, and can be manufactured with high yield. An object of the present invention is to provide a fiber / resin composite composition pellet.
Another object of the present invention is to provide a resin composition for electromagnetic wave shielding using the fiber / resin composite composition pellet for electromagnetic wave shielding and a molded product thereof.

  As a result of intensive studies on the electromagnetic wave shielding fiber / resin composite composition pellets, the present inventors use a polycarbonate resin having a viscosity average molecular weight of 7,000 to 13,000 as the polycarbonate resin impregnated in the conductive fiber. Thus, the polycarbonate resin can be easily and sufficiently impregnated into a long fiber bundle of conductive fibers, and an electromagnetic shielding fiber / resin composite composition pellet can be produced with high yield. Even in a molded product obtained by molding a resin composition obtained by heat-melting and kneading with a thermoplastic resin, even if the molded product is simply mixed and molded without heating and melting, the mechanical strength, heat resistance, etc. are reduced. It has been found that a molded product having a small surface appearance and a good surface appearance can be obtained.

  The present invention has been achieved based on such knowledge, and the gist thereof is as follows.

[1] A long fiber bundle of at least one conductive fiber (B) selected from metal fibers, carbon fibers, and metal-coated non-metal fibers, and a polycarbonate resin (A) having a viscosity average molecular weight of 7,000 to 13,000 A fiber / resin composite composition pellet for electromagnetic wave shielding, wherein the long fiber bundle has a fiber diameter of 1 to 50 μm, and the long fiber bundle is impregnated with the polycarbonate resin (A).

[2] The polycarbonate resin (A) is formed by blending 50 to 300 parts by mass of a polycarbonate oligomer having a viscosity average molecular weight of 1000 to 10,000 with respect to 100 parts by mass of a polycarbonate resin having a viscosity average molecular weight of 14,000 to 18,000. The electromagnetic wave shielding fiber / resin composite composition pellet according to [1], wherein

[3] The electromagnetic shielding fiber according to [1] or [2], wherein the long fiber bundle of the conductive fiber (B) is formed by converging 5,000 to 35,000 long fibers. / Resin composite composition pellets.

[4] The fiber / resin composite composition pellet for electromagnetic wave shielding according to any one of [1] to [3], wherein the length of the pellet is 2 to 15 mm.

[5] The fiber / resin composite pellet for electromagnetic wave shielding according to [4], wherein the length of the pellet is 4 to 10 mm.

[6] Any one of [1] to [5], wherein the conductive fiber (B) is at least one metal fiber selected from stainless steel fiber, aluminum fiber, copper fiber, and brass fiber. The fiber / resin composite composition pellet for electromagnetic wave shielding as described.

[7] The metal-coated non-metallic fiber has a surface of at least one non-metallic fiber selected from glass fiber, aramid fiber, polyester fiber, and carbon fiber, gold, silver, copper, nickel, aluminum, cobalt, iron, The electromagnetic shielding fiber according to any one of [1] to [6], which is coated with at least one metal selected from zinc, tin and an alloy containing one or more of these metals Resin composite composition pellets.

[8] A pellet obtained by passing a continuous fiber bundle of conductive fibers (B) through the impregnation treatment zone of the polycarbonate resin (A) and further cutting the pellets [1] to [7] The fiber / resin composite composition pellet for electromagnetic wave shielding according to any one of the above.

[9] The electromagnetic wave shielding fiber / resin composite composition pellet according to any one of [1] to [8], wherein the content of the conductive fiber (B) is 20 to 80% by mass.

[10] A resin composition for electromagnetic wave shielding, comprising a thermoplastic resin (C) and the fiber / resin composite composition pellet for electromagnetic wave shielding according to any one of [1] to [9].

[11] The content of the fiber / resin composite composition pellet for electromagnetic wave shielding according to any one of [1] to [9] with respect to 100 parts by mass of the thermoplastic resin (C) is 3 to 300 parts by mass. The resin composition for electromagnetic wave shields according to [10].

[12] A pellet mixture obtained by mixing a pellet of thermoplastic resin (C) and a fiber / resin composite composition pellet for electromagnetic wave shielding according to any one of [1] to [9]. The resin composition for electromagnetic wave shields according to [10] or [11].

[13] A melt-kneaded product obtained by melt-kneading the thermoplastic resin (C) and the electromagnetic shielding fiber / resin composite composition pellet according to any one of [1] to [9]. The resin composition for electromagnetic wave shields as described in [10] or [11].

[14] A pellet formed by mixing and pelletizing the thermoplastic resin (C) and the fiber / resin composite composition pellet for electromagnetic wave shielding according to any one of [1] to [9]. The resin composition for electromagnetic wave shields according to [10] or [11].

[15] The resin composition for electromagnetic wave shielding according to [14], wherein the pellet has a length of 2.5 to 15 mm.

[16] The electromagnetic wave shielding resin composition according to [15], wherein the pellet has a length of 5.1 to 13 mm.

[17] The resin composition for electromagnetic wave shielding according to any one of [10] to [16], wherein the thermoplastic resin (C) includes an aromatic polycarbonate resin.

[18] In the above [17], the thermoplastic resin (C) is an aromatic polycarbonate resin having a viscosity average molecular weight of 14,000 to 30,000 or an alloy of the aromatic polycarbonate resin and an ABS resin. The resin composition for electromagnetic wave shielding as described.

[19] A resin molded product for electromagnetic wave shielding, comprising the resin composition for electromagnetic wave shielding according to any one of [10] to [18].

  According to the present invention, the polycarbonate resin (A) having a viscosity average molecular weight of 7,000 to 13,000 is used as the polycarbonate resin impregnated into the long fiber bundle of the conductive fiber (B). Can be easily and sufficiently impregnated into a long fiber bundle of conductive fibers (B) to produce fiber / resin composite composition pellets with high yield. Further, by using this fiber / resin composite composition pellet, an electromagnetic shielding fiber / resin composite composition obtained by heating and kneading the fiber / resin composite composition pellet and the thermoplastic resin (C) is molded. Even if the molded body is molded, or a molded body that is simply mixed without being heated and melted, there is little decrease in mechanical strength, heat resistance, etc., and a resin molded body for electromagnetic wave shielding with a good surface appearance is obtained. It becomes possible.

  Hereinafter, embodiments of the present invention will be described in detail.

[Electromagnetic wave shielding fiber / resin composite composition pellet]
The electromagnetic wave shielding fiber / resin composite composition pellet of the present invention (hereinafter sometimes referred to as “pellet (A / B)”) is a polycarbonate resin (A) having a viscosity average molecular weight of 7,000 to 13,000, It is made by impregnating a long fiber bundle of conductive fibers (B).

<Polycarbonate resin (A)>
In the pellet (A / B) of the present invention, the polycarbonate resin (A) impregnated in the conductive fiber (B) has a viscosity average molecular weight of 7,000 to 13,000. Here, the viscosity average molecular weight (Mv) of the polycarbonate resin is based on the value of the intrinsic viscosity [η] (unit: dl / g) measured at a temperature of 25 ° C. for a solution in which methylene chloride is used as a solvent and the polycarbonate resin is dissolved. The following formula:
[Η] = K (Mv) ^α
(Where K = 1.23 × 10 ⁻⁴ , α = 0.83)
It is indicated by the value converted by.

  As the impregnating polycarbonate resin (A), the viscosity average molecular weight (Mv) needs to be in the range of 7,000 to 13,000, but the viscosity average molecular weight is preferably 8,000 to 12,000, More preferably, it is in the range of 9,000 to 11,000. If the viscosity average molecular weight is less than 7,000, the impregnated resin is brittle and the pellets (A / B) are cracked and the long fiber bundles are scattered. If the viscosity average molecular weight exceeds 13,000, the impregnated resin has a high viscosity. Since the impregnation of the fiber bundle becomes difficult and the long fiber bundle comes out of the impregnation resin, it is not preferable.

  In the present invention, as the polycarbonate resin (A) as the fiber impregnation resin, any of an aromatic polycarbonate, an aliphatic polycarbonate, and an aromatic-aliphatic polycarbonate can be used, and among them, an aromatic polycarbonate is preferable. The aromatic polycarbonate is an aromatic polycarbonate polymer or copolymer obtained by reacting one or more aromatic dihydroxy compounds with phosgene or a diester of carbonic acid.

Typical examples of the aromatic dihydroxy compound include, for example, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, and 2,2-bis (4-hydroxy-3-methylphenyl). Propane, 2,2-bis (4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-) 3,5-dibromophenyl) propane, 4,4-bis (4-hydroxyphenyl) heptane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4′-dihydroxybiphenyl, 3,3 ′, 5 5′-tetramethyl-4,4′-dihydroxybiphenyl, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfone Examples thereof include rufide, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ketone and the like. These aromatic dihydroxy compounds can be used alone or in admixture of two or more.
Among these aromatic dihydroxy compounds, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) is preferable.

In the reaction, together with the aromatic dihydroxy compound, three or more hydroxy groups in a molecule such as 1,1,1-tris (4-hydroxylphenyl) ethane, 1,3,5-tris (4-hydroxyphenyl) benzene, etc. A small amount of a polyhydric phenol having a group can be used as a branching agent.
In addition, for the purpose of further enhancing the flame retardancy, a compound or oligomer having both ends of a phenolic OH group having a siloxane structure and / or a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compound is used. You can also

  On the other hand, examples of carbonic acid diesters include diaryl carbonates such as diphenyl carbonate and ditolyl carbonate, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate. These carbonic acid diesters and phosgene are used alone or in combination of two or more. Can be used.

  The polycarbonate resin (A) used for impregnating the long fiber bundle of the conductive fibers (B) is preferably a polycarbonate polymer derived from 2,2-bis (4-hydroxyphenyl) propane, or 2,2 -Polycarbonate copolymers derived from bis (4-hydroxyphenyl) propane and other aromatic dihydroxy compounds. Furthermore, two or more kinds of other aromatic dihydroxy compounds may be used in combination.

  A polycarbonate resin (A) having a viscosity average molecular weight of 7,000 to 13,000, which is an impregnation resin, is directly obtained by reacting an aromatic dihydroxy compound with phosgene or a carbonic acid diester using an appropriate molecular weight regulator. The obtained polycarbonate resin such as aromatic polycarbonate resin or a commercially available product thereof may be used as it is, but is separately produced or commercially available, such as a polycarbonate resin such as an aromatic polycarbonate resin having a large molecular weight, and an aromatic having a small molecular weight. It is preferable to blend with a polycarbonate oligomer such as a polycarbonate oligomer and use it as a polycarbonate resin (A) having a predetermined viscosity average molecular weight from the viewpoint of maintaining appropriate impregnation properties and strength.

  Specifically, 50 to 300 parts by mass, preferably 100 to 200 parts by mass of a polycarbonate oligomer having a viscosity average molecular weight of 1000 to 10,000 is added to 100 parts by mass of a polycarbonate resin having a viscosity average molecular weight of 14,000 to 18,000. And it is preferable to use it as a polycarbonate resin (A) which has a predetermined viscosity average molecular weight. Such a polycarbonate oligomer tends to bleed out from the molded product at the time of molding if the viscosity average molecular weight or the degree of polymerization is too small, while satisfactory impregnation, fluidity and surface smoothness are obtained when the viscosity average molecular weight or the degree of polymerization is large. Since it becomes difficult, it is preferably a polycarbonate oligomer having a viscosity average molecular weight of 1000 to 10,000 and an average degree of polymerization of 2 to 15, particularly preferably an aromatic polycarbonate oligomer.

  In this case, the method for producing the polycarbonate resin and the polycarbonate oligomer, which are blending components of the polycarbonate resin (A) as the impregnating resin, is not particularly limited, and the phosgene method (interfacial polymerization method) or the melting method ( It can be produced by a transesterification method). Furthermore, it is also possible to use a polycarbonate resin produced by a melting method and having an adjusted amount of terminal OH groups. In addition, in the method for producing a polycarbonate oligomer, it is important to achieve a suitable average degree of polymerization by reacting with a suitable molecular weight regulator. Specific examples of suitable molecular weight regulators include compounds having a monovalent phenolic hydroxyl group and compounds having an aromatic carboxylic acid group, such as ordinary phenol, pt-butylphenol, 2, 3, In addition to 6-tribromophenol and the like, long-chain alkylphenols, aliphatic carboxylic acid chlorides, aliphatic carboxylic acids, hydroxybenzoic acid, and the like can be mentioned.

  Specific examples of polycarbonate oligomers include bisphenol A polycarbonate oligomers terminated with pt-butylphenol, and polycarbonate oligomers of tetrabromobisphenol A and bisphenol A terminated with pt-butylphenol. However, it is not always necessary that the oligomer is produced by the same raw materials and reaction methods as those of the polycarbonate resin having a viscosity average molecular weight of 14,000 to 18,000.

  As a polycarbonate resin having a viscosity average molecular weight of 7,000 to 13,000 or 14,000 to 18,000, not only a virgin raw material but also a polycarbonate resin regenerated from a used product, a so-called material recycled polycarbonate resin is used. Is also possible. Used products include optical recording media such as optical disks, light guide plates, automobile window glass and automobile headlamp lenses, vehicle transparent members such as windshields, containers such as water bottles, glasses lenses, soundproof walls and glass windows, waves A building member such as a plate is preferred. Further, as the recycled polycarbonate resin, non-conforming products, sprue, pulverized products obtained from runners or the like, or pellets obtained by melting them can be used.

  Moreover, the polycarbonate resin (A) used by this invention is 1 type (s) or 2 or more types of what was illustrated as various additives used for the resin composition for electromagnetic wave shield of this invention mentioned later. ) May be included as long as the characteristics are not impaired.

<Conductive fiber (B)>
The conductive fiber (B) impregnated with the polycarbonate resin (A) is at least one conductive fiber (B) selected from metal fibers, carbon fibers, and metal-coated non-metallic fibers. Practically, the conductive fiber (B) has a length of preferably 5,000 to 35,000, more preferably 5,000 to 20,000, particularly preferably 5,000 to 10,000. The fiber bundle is preferable in terms of electromagnetic shielding properties and productivity in the impregnation step. If the number of the bundles is too small, the conductivity of the resin composition for electromagnetic wave shielding containing the pellets (A / B) using the same may be insufficient, and the pellet diameter of the pellets (A / B) may be too small. When it is too thin and melt kneaded with the thermoplastic resin (C), it becomes easy to separate, and the dispersion of the conductive fibers (B) in the resin composition for electromagnetic wave shielding may become uneven. Conversely, if the number of bundles is too large, the polycarbonate resin (A) may not penetrate to the center of the fiber bundle, and the dispersion of the conductive fibers (B) in the resin composition for electromagnetic wave shielding becomes non-uniform. There is.

  As the fiber diameter per one conductive fiber (B), if it is too thin, the fiber is easily cut. As a result, the electromagnetic wave shield obtained by using the pellet (A / B) containing this conductive fiber (B) There is a possibility that the electromagnetic wave shielding property of the resin composition for use may be lowered, and if it is too thick, the moldability is impaired, so that the average fiber diameter is preferably about 1 to 50 μm, particularly about 3 to 20 μm.

As the metal fiber of the conductive fiber (B), it is preferable to use at least one selected from stainless steel fiber, aluminum fiber, copper fiber and brass fiber from the viewpoint of electromagnetic wave shielding performance and cost.
Carbon fibers are slightly inferior to metal fibers in terms of electromagnetic shielding performance, but are preferred for weight reduction because of their lower specific gravity than metals. As the carbon fiber, a PAN-based carbon fiber is preferable from the viewpoint of strength. Further, carbon nanofibers are also preferable.

  Moreover, as a coating metal used for a metal coat nonmetallic fiber, the metal which has favorable electroconductivity and is hard to oxidize is preferable. Specifically, the metal-coated non-metallic fiber is at least one metal selected from gold, silver, copper, nickel, aluminum, cobalt, iron, zinc, tin, and an alloy containing one or more of these metals. It is preferable to use a metal-coated non-metallic fiber covering the surface of at least one non-metallic fiber selected from glass fiber, aramid fiber, polyester fiber and carbon fiber. As the coating metal, gold and silver are particularly preferably used from the viewpoint of conductivity, and nickel and copper are preferably used from the viewpoint of cost. The method for coating the nonmetallic fiber is not particularly limited, but electroless plating is common. However, other methods such as vacuum deposition and sputtering can be used. In the case of nickel, a nickel coating method in nickel carbonyl gas generated during nickel refining can also be mentioned. The amount of the coated metal is appropriately determined depending on the kind of non-metallic fiber and metal to be used and the required volume resistivity, but it is desirable to coat the fiber surface with a thickness of 0.1 to 1.0 μm. In the case of silver, nickel and nickel copper, a thickness of 0.1 mm to 0.7 μm is preferable. Therefore, the average fiber diameter of the non-metallic fiber of the metal-coated non-metallic fiber is such that the metal is coated to such a thickness and falls within the preferable average fiber diameter of the conductive fiber (B). The fiber diameter is preferred.

  These conductive fibers (B) may be treated with a surface treatment agent such as a known coupling agent or sizing agent for the purpose of improving the mechanical strength and conductivity of the pellet (A / B). .

  In the present invention, as the conductive fiber (B), a copper-coated aramid fiber is particularly preferably used from the comprehensive viewpoints such as economy, specific gravity, electromagnetic wave shielding property, mechanical strength, and appearance.

<Fiber content>
The content of the conductive fiber (B) in the pellet (A / B) of the present invention depends on the type of the conductive fiber (B) to be used, but from the viewpoint of the ease of impregnation of the fiber and the electromagnetic shielding effect, It is preferable that it is 20-80 mass%, More preferably, it is 20-75 mass%.

<Method for producing pellet (A / B)>
There is no particular limitation on the method for producing the pellet (A / B) of the present invention by impregnating the polycarbonate resin (A) into the conductive fiber (B), and a known method can be used. The pultrusion method is preferable for producing a fiber / resin composite composition pellet containing long fiber bundles of conductive fibers (B) arranged in parallel.

The pultrusion method is basically impregnating a resin while passing a predetermined impregnation treatment region while drawing a continuous fiber bundle.
(1) A method in which a fiber bundle is passed through an impregnation bath containing a resin emulsion, suspension, or solution, impregnated, and then dried. (2) A resin powder is sprayed on the fiber bundle or in a tank containing the powder. A method in which the fiber bundle is passed through and the resin powder is adhered to the fiber, and then the resin is melted and impregnated. (3) The molten resin is passed from the extruder or the like to the crosshead die while passing the fiber bundle through the crosshead die. There are known methods of supplying and impregnating, and any of these known methods can be used in the present invention. Particularly preferred is a method using a crosshead die.

  Hereinafter, the method for producing pellets (A / B) of the present invention will be described in more detail by taking a pultrusion method using a crosshead die as an example. Of course, the manufacturing method of the pellet (A / B) of the present invention is not limited to the apparatus and method exemplified here.

  In producing the pellets (A / B) of the present invention by the pultrusion method, first, a continuous fiber bundle of conductive fibers (B) is supplied to the crosshead die. The type of conductive fiber (B) used is at least one selected from the aforementioned metal fibers, carbon fibers, and metal-coated non-metal fibers, and the form thereof is continuous fibers such as roving, yarn, and filament. Any of them can be used regardless of the presence or absence of twist. In particular, a roving shape is preferable in terms of easy handling.

  In the present invention, prior to the impregnation treatment with the polycarbonate resin (A), for example, a heating device or the like is installed, and the conductive fiber (B) is preheated to a high temperature to maintain the high temperature. It is preferable to contact the polycarbonate resin (A). In addition, the fiber bundle of the conductive fiber (B) is opened with a tension roll or the like until the impregnation treatment, because the fiber bundle can be easily impregnated with the polycarbonate resin (A). preferable.

On the other hand, from an extruder or the like connected to the crosshead die, polycarbonate resin (A) as an impregnating resin (this polycarbonate resin (A) may contain various additives as necessary. ) Is required to be higher than the melting point or glass transition temperature of the impregnating resin.
The resin impregnated composition thus obtained contains conductive fibers (B) arranged substantially in parallel, and the polycarbonate resin (A) is sufficient for the fiber bundle of the conductive fibers (B). A fiber / resin composite composition impregnated and bonded to each other.

  The strand drawn from the crosshead die is cut into pellets of any length, preferably 2 to 15 mm, more preferably 4 to 10 mm according to the purpose of use, and the pellet (A / B) of the present invention is obtained. It is done. The pellet (A / B) includes a fiber bundle of conductive fibers (B) having the same length as the pellet.

  When the pellet length of the pellet (A / B) obtained in this way is too short, the length of the conductive fiber (B) in the pellet is also short, and the electromagnetic shielding resin obtained by using this The electromagnetic shielding property of the composition tends to be lowered, and if this is too long, when the pellet is melt-kneaded and extruded with the thermoplastic resin (C) described later, fibers are entangled in the extruder, the extruder is blocked, etc. In the case of remarkable decrease in productivity, production becomes defective.

[Resin composition for electromagnetic wave shielding]
The resin composition for electromagnetic wave shielding of the present invention (hereinafter sometimes referred to as “resin composition (A / B / C)”) includes the above-described pellet (A / B) of the present invention and a thermoplastic resin. (C).

<Thermoplastic resin (C)>
As the thermoplastic resin (C) used in the resin composition (A / B / C) of the present invention, depending on the intended use and required performance of the molded product obtained by molding the resin composition for electromagnetic wave shielding of the present invention. Polystyrene resin such as polycarbonate resin and ABS resin, polyester resin such as polybutylene terephthalate resin and polyethylene terephthalate resin, alloy of polycarbonate resin and styrene resin such as ABS resin, polycarbonate resin and polybutylene terephthalate resin Examples of such an alloy include alloys of polycarbonate resin and polyethylene terephthalate resin, and polyolefin resins such as polypropylene and polyethylene. Above all, when impact resistance and dimensional accuracy are required, polycarbonate resin, alloy of styrenic resin such as polycarbonate resin and ABS resin, and when heat resistance and chemical resistance are required, Those containing polycarbonate, such as an alloy of polybutylene terephthalate resin or polyethylene terephthalate resin, are selected. The thermoplastic resin (C) is preferably a polycarbonate resin or an alloy of a polycarbonate resin and an ABS resin.

  The polycarbonate resin as the preferred thermoplastic resin (C) according to the present invention is similar to the polycarbonate resin (A) for fiber impregnation of the pellet (A / B) of the present invention, and is an aromatic polycarbonate resin, an aliphatic polycarbonate resin, Any of aromatic-aliphatic polycarbonate resins can be used, and among them, aromatic polycarbonate resins are preferred. The aromatic polycarbonate resin is an aromatic polycarbonate polymer or copolymer obtained by reacting one or more aromatic dihydroxy compounds with phosgene or a carbonic acid diester.

  The aromatic polycarbonate resin as the thermoplastic resin (C) has a viscosity average molecular weight (M) in the range of 14,000 to 30,000, particularly 15,000 to 28,000, especially 16,000 to 26,000. 000 is preferred. An aromatic polycarbonate resin having a viscosity-average molecular weight that is too small is not preferable because the mechanical strength is insufficient, and if it is too large, it tends to cause difficulty in moldability.

  The aromatic polycarbonate resin can be used as an alloy with a styrene resin such as the following ABS resin, an alloy with a polybutylene terephthalate resin, an alloy with a polyethylene terephthalate resin, or the like.

  The polyethylene terephthalate resin (PET) may be produced by either a transesterification reaction between dimethyl terephthalate and ethylene glycol or a direct esterification reaction between terephthalic acid and ethylene glycol.

  The polybutylene terephthalate resin (PBT) may be produced by either a DMT method by transesterification of dimethyl terephthalate and 1,4-butanediol, or a direct polymerization method of terephthalic acid and 1,4-butanediol.

  In either case of the PET or PBT, phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, and the like together with terephthalic acid or a dialkyl ester thereof during the polycondensation reaction Dibasic acids such as dialkyl esters, tribasic acids and the like, and dialkyl esters thereof can be used. It is preferable that these usage-amounts are the range of 40 mass parts or less with respect to 100 mass parts of terephthalic acid or its dialkyl ester.

  Similarly, during the polycondensation reaction, together with ethylene glycol or 1,4-butanediol, as other aliphatic glycols, for example, ethylene glycol, propylene glycol, 1,4-butanediol, hexamethylene glycol, etc., aliphatic In addition to glycol, other diols such as cyclohexanediol, cyclohexanedimethanol, xylene glycol, 2,2-bis (4-hydroxyphenyl) propane, glycerin, pentaerythritol, and polyhydric alcohols can be used in combination. The amount of these diols or polyhydric alcohols used is preferably in the range of 40 parts by mass or less with respect to 100 parts by mass of the aliphatic glycol. Moreover, it is preferable that these usage-amounts are the range of 40 mass parts or less with respect to 100 mass parts of terephthalic acid or its dialkyl ester.

  The molecular weight of polyester resins such as PET and PBT is an intrinsic viscosity measured at 30 ° C. in a mixed solvent of phenol and tetrachloroethane (weight ratio = 50/50), preferably 0.5 to 1.8. More preferably, it is 0.7-1.5.

  Examples of the styrene resin include acrylonitrile-styrene copolymer, acrylonitrile-styrene-butadiene copolymer (ABS resin), acrylonitrile-ethylenepropylene rubber-styrene copolymer, acrylonitrile-styrene-acrylic rubber copolymer, and the like. it can. Examples of the polymerization method of these styrene resins include a bulk polymerization method and an emulsion polymerization method.

Furthermore, as the thermoplastic resin (C), it is possible to use not only virgin raw materials but also thermoplastic resins regenerated from used products, non-conforming products, sprues, runners, and the like.
As the aromatic polycarbonate resin of the thermoplastic resin (C), not only virgin raw materials but also aromatic polycarbonate resins regenerated from used products, so-called material-recycled aromatic polycarbonate resins can be used. Used products include optical recording media such as optical discs, light guide plates, automobile window glass and automobile headlamp lenses, vehicle transparent members such as windshields, containers such as water bottles, eyeglass lenses, soundproof walls and glass windows, waves A building member such as a plate is preferred. In addition, as the recycled aromatic polycarbonate resin, non-conforming products, pulverized products obtained from sprues or runners, or pellets obtained by melting them can be used.

<Content of pellet (A / B)>
The content of the pellet (A / B) contained in the resin composition (A / B / C) of the present invention depends on the required properties depending on the purpose of use of the resin composition (A / B / C) and the pellet (A / B). ) Depending on the content of the conductive fiber (B), etc. in the thermoplastic resin (C) (only the thermoplastic resin (C) that does not contain various additives described later) for 100 parts by mass of the pellet ( A / B) is preferably from 3 to 300 parts by mass, particularly from 3 to 100 parts by mass, from the viewpoint of balance between electromagnetic shielding properties, equipment physical properties, and fluidity. If the content of the pellet (A / B) relative to the thermoplastic resin (C) is too small, the required electromagnetic shielding properties cannot be obtained, and if it is too large, the moldability and the mechanical strength and appearance of the resulting molded product are poor. It tends to be inferior.

<Form of resin composition (A / B / C)>
The resin composition (A / B / C) of the present invention is
(1) Mixture obtained by dry blending pellets (A / B) and thermoplastic resin (C) together with various additives described below as needed (2) Pellet (A / B) pellets and thermoplastic resin ( C) pellets (this thermoplastic resin (C) pellets may contain various additives described later) pellet mixture (3) pellets (A / B) and thermoplastic resin ( C) and a melt-kneaded product obtained by melt-kneading together with various additives used as necessary (this melt-kneaded product may be a product obtained by melt-kneading the pellet mixture).
(4) Pellets formed by mixing pellets (A / B) and thermoplastic resin (C) together with various additives described below as needed to form pellets (this pellet is obtained by melting and kneading the above pellet mixture) Or may be pelletized from the above melt-kneaded product.)
And can be used as various molding materials.

  As a method for mixing the pellet (A / B) and the thermoplastic resin (C) to obtain the resin composition (A / B / C), various kneaders such as uniaxial and multi-axial kneaders, Banbury A method of kneading pellets (A / B), thermoplastic resin (C), and various additives blended as necessary using a mixer, roll, Brabender plastogram, etc., then cooling and solidifying, or an appropriate solvent For example, to a hydrocarbon such as hexane, heptane, benzene, toluene, xylene and derivatives thereof, pellets (A / B), thermoplastic resin (C) and various additives blended as necessary are added, For example, a solution mixing method in which dissolved components or dissolved components and insoluble components are mixed in a suspended state is used. From the industrial cost, the melt-kneading method is preferable, but it is not limited thereto. In melt kneading, it is preferable to use a single-screw or twin-screw extruder.

<Resin composition (A / B / C) pellet>
When the resin composition (A / B / C) of the present invention is in the form of pellets, the length is preferably 2.5 to 15 mm, particularly 4 to 13 mm. If this length is too short, the fiber length of the conductive fibers (B) contained in the pellet may be shortened by cutting, and electromagnetic shielding properties may be reduced. If it is too long, molding is performed using this pellet. When performing, the supply of pellets becomes unstable.

  In particular, in the present invention, a pellet (A / B) pellet having a pellet length of 2 to 15 mm, preferably 4 to 10 mm, is melt-kneaded with the thermoplastic resin (C) and the pellet length is 2.5 to 15 mm, preferably 5.1. By forming pellets of ˜13 mm, the conductive fibers (B) can be uniformly dispersed at a high aspect ratio in the resin composition (A / B / C), and the variation between shots is small and excellent. A resin molded body for electromagnetic wave shielding having both conductivity, mechanical strength and appearance can be obtained, which is preferable.

<Various additives>
In addition to the thermoplastic resin (C) and pellets (A / B), the resin composition (A / B / C) of the present invention is a flame retardant, dripping as long as the object of the present invention is not impaired as required. Inhibitors (flame retardant aids), reinforcing materials, impact modifiers, mold release agents, colorants (dyeing pigments), compatibilizers, flow modifiers, UV absorbers, stabilizers (phosphorous stabilizers, (Phenolic stabilizers), antistatic agents, antifogging agents, lubricants / antiblocking agents, plasticizers, dispersants, antibacterial agents, inorganic fillers and the like.
As described above, these additives may be contained in the pellet (A / B) contained in the resin composition (A / B / C) of the present invention, and in the pellet of the thermoplastic resin (C). It may be contained, and may be used together with the pellet (A / B) and the thermoplastic resin (C) in the preparation of the resin composition (A / B / C).

  Below, the flame retardant etc. which are typical additives among these various additives are demonstrated.

{Flame retardants}
The flame retardant is not particularly limited as long as it improves the flame retardancy of the resin composition (A / B / C) of the present invention, but a phosphoric acid ester compound, an organic sulfonic acid metal salt, and a silicone compound are suitable. is there.

(Phosphate compound)
As the phosphate ester compound (phosphate ester flame retardant), for example, a compound represented by the following formula (1) is preferable.

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently an aryl group which may be substituted, and X is a divalent aromatic which may have another substituent. And n represents a number of 0 to 5.)

In the above formula (1), examples of the aryl group represented by R _{1 to} R ₄ include a phenyl group and a naphthyl group. Examples of the divalent aromatic group represented by X include a phenylene group, a naphthylene group, and a group derived from, for example, bisphenol. Examples of these substituents include an alkyl group, an alkoxy group, and a hydroxy group. When n is 0, the compound represented by formula (1) is a phosphate ester, and when n is greater than 0, it is a condensed phosphate ester (including a mixture).

  Specific examples of the compound represented by the above formula (1) include bisphenol A bisphosphates, hydroquinone bisphosphates, resorcinol bisphosphates, and substituted and condensates thereof. Examples of commercially available condensed phosphate compounds that can be suitably used as such components include “CR733S” (resorcinol bis (diphenyl phosphate)) and “CR741” (bisphenol A bis (diphenyl) from Daihachi Chemical Industry Co., Ltd. Phosphate)), “PX200” (resorcinol bis (dixylenyl phosphate)), “Adekastab FP-700” (2,2-bis (p-hydroxyphenyl) propane / trichlorophosphine oxide polycondensation from Asahi Denka Kogyo Co., Ltd. Products (phenol condensates having a degree of polymerization of 1 to 3), and are readily available.

  Content of such a phosphate ester type flame retardant in the resin composition (A / B / C) of the present invention is 1 to 50 parts by mass, preferably 100 parts by mass of the thermoplastic resin (C). It is 3-40 mass parts, Most preferably, it is 5-30 mass parts. If the content of the phosphate ester flame retardant is less than 1 part by mass, the flame retardancy is insufficient, and if it exceeds 50 parts by mass, the heat resistance is excessively lowered, which is not preferable.

(Organic sulfonic acid metal salt)
Preferred examples of the organic sulfonic acid metal salt include aliphatic sulfonic acid metal salts and aromatic sulfonic acid metal salts. The metal constituting the organic sulfonic acid metal salt is preferably an alkali metal, an alkaline earth metal, etc., and the alkali metal and the alkaline earth metal include sodium, lithium, potassium, rubidium, cesium, beryllium, magnesium. , Calcium, strontium and barium. The organic sulfonic acid metal salt can also be used by mixing two or more kinds of salts.

  As the aliphatic sulfonate, a fluoroalkane-sulfonic acid metal salt is preferable, and a perfluoroalkane-sulfonic acid metal salt is more preferable. Preferred examples of the fluoroalkane-sulfonic acid metal salt include an alkali metal salt of fluoroalkane-sulfonic acid, an alkaline earth metal salt of fluoroalkane-sulfonic acid, and more preferably, a fluoroalkane having 4 to 8 carbon atoms. Examples include alkali metal salts and alkaline earth metal salts of alkanesulfonic acid. Specific examples of the fluoroalkane-sulfonic acid metal salt include perfluorobutane-sodium sulfonate, perfluorobutane-potassium sulfonate, perfluoromethylbutane-sodium sulfonate, perfluoromethylbutane-potassium sulfonate, perfluoro Examples include octane-sodium sulfonate and potassium perfluorooctane-sulfonate.

  The aromatic sulfonic acid metal salt is preferably an aromatic sulfonic acid alkali metal salt, an aromatic sulfonic acid alkaline earth metal salt, an aromatic sulfone sulfonic acid alkali metal salt, or an aromatic sulfone sulfonic acid alkaline earth metal. Salts, and the like, and the aromatic sulfonesulfonic acid alkali metal salt and the aromatic sulfonesulfonic acid alkaline earth metal salt may be a polymer. Specific examples of the aromatic sulfonic acid metal salt include 3,4-dichlorobenzenesulfonic acid sodium salt, 2,4,5-trichlorobenzenesulfonic acid sodium salt, benzenesulfonic acid sodium salt, diphenylsulfone-3-sulfonic acid. Sodium salt, potassium salt of diphenylsulfone-3-sulfonic acid, sodium salt of 4,4′-dibromodiphenyl-sulfone-3-sulfonic acid, potassium salt of 4,4′-dibromodiphenyl-sulfone-3-sulfonic acid 4-chloro-4′-nitrodiphenylsulfone-3-sulfonic acid calcium salt, diphenylsulfone-3,3′-disulfonic acid disodium salt, diphenylsulfone-3,3′-disulfonic acid dipotassium salt, and the like. Can be mentioned.

  The compounding amount of the organic sulfonic acid metal salt is preferably 0.01 to 5 parts by mass, more preferably 0.02 to 3 parts by mass, and particularly preferably 0.03 to 3 parts by mass with respect to 100 parts by mass of the thermoplastic resin (C). 2 parts by mass. When the amount of the organic sulfonic acid metal salt is less than 0.01 parts by mass, sufficient flame retardancy is difficult to obtain, and when it exceeds 5 parts by mass, the thermal stability tends to be lowered.

(Silicone compound)
The silicone compound (silicone flame retardant) is preferably a polyorganosiloxane having a linear or branched structure. The organic group possessed by the polyorganosiloxane includes hydrocarbons such as alkyl groups and substituted alkyl groups having 1 to 20 carbon atoms, vinyl and alkenyl groups, cycloalkyl groups, and aromatic hydrocarbon groups such as phenyl and benzyl. Chosen from.

Even if polydiorganosiloxane does not contain a functional group, it may contain a functional group. In the case of a polydiorganosiloxane containing a functional group, the functional group is preferably a methacryl group, an alkoxy group or an epoxy group.
These polyorganosiloxanes may be supported on silica.

  The compounding amount of the silicone compound is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 7 parts by mass, and particularly preferably 0.5 to 7 parts by mass with respect to 100 parts by mass of the thermoplastic resin (C). It is. When the compounding amount of the silicone compound is less than 0.5 parts by mass, sufficient flame retardancy is difficult to obtain, and when it exceeds 10 parts by mass, the mechanical strength and heat resistance are likely to decrease.

{Anti-dripping agent}
In the present invention, an anti-dripping agent can be included for the purpose of preventing dripping during combustion. As the dripping inhibitor, a fluororesin is preferably used.

  Here, the fluororesin is a polymer or copolymer containing a fluoroethylene structure, for example, a difluoroethylene polymer, a tetrafluoroethylene polymer, a tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene and fluorine. It is a copolymer with an ethylene monomer that does not contain. Polytetrafluoroethylene (PTFE) is preferable, and the average molecular weight is preferably 500,000 or more, and particularly preferably 500,000 to 10,000,000.

  If polytetrafluoroethylene having fibril forming ability is used, it is possible to impart even higher melt drip prevention. Although there is no restriction | limiting in particular in the polytetrafluoroethylene (PTFE) which has a fibril formation ability, For example, what is classified into the type 3 in ASTM standard is mentioned. Specific examples thereof include, for example, Teflon (registered trademark) 6-J (manufactured by Mitsui DuPont Fluorochemical Co., Ltd.), Polyflon D-1, Polyflon F-103, Polyflon F201 (Daikin Industries, Ltd.), CD076 Asahi IC Fluoropolymers Co., Ltd.). Other than those classified as type 3, for example, Argoflon F5 (manufactured by Montefluos Co., Ltd.), polyflon MPA, polyflon FA-100 (manufactured by Daikin Industries, Ltd.) and the like can be mentioned. These polytetrafluoroethylene (PTFE) may be used independently and may combine 2 or more types.

Polytetrafluoroethylene (PTFE) having the fibril-forming ability as described above is prepared by, for example, using tetrafluoroethylene in an aqueous solvent in the presence of sodium, potassium, ammonium peroxydisulfide, at a pressure of 1 to 100 psi, at a temperature of 0. It is obtained by polymerizing at ˜200 ° C., preferably 20˜100 ° C.
Further, the anti-dripping agent may be Teflon (registered trademark) 30-J (manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) dispersed in a solvent.

  The anti-dripping agent may be a polytetrafluoroethylene-containing mixed powder composed of polytetrafluoroethylene particles and organic polymer particles. Specific examples of monomers for producing organic polymer particles include styrene, p-methylstyrene, o-methylstyrene, p-chlorostyrene, o-chlorostyrene, p-methoxystyrene, o-methoxystyrene. Styrene monomers such as 2,4-dimethylstyrene, α-methylstyrene, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate (Meth) acrylic acid ester-based single quantities such as 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridodecyl acrylate, tridodecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate , Vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether, vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate, ethylene, propylene, isobutylene Examples thereof include, but are not limited to, olefin monomers such as diene monomers such as butadiene, isoprene and dimethylbutadiene. Preferably, two or more kinds of polymers or copolymers of these monomers can be used to obtain organic polymer particles. As such a thing, A-3800 (Methyl methacrylate, butyl acrylate copolymer, tetrafluoroethylene polymer mixed powder) manufactured by Mitsubishi Rayon can be exemplified.

  It is preferable that the compounding quantity of a dripping inhibitor is 0.01-1 mass part with respect to 100 mass parts of thermoplastic resins (C), especially 0.1-0.5 mass part. When the blending amount of the anti-dripping agent is too small, the flame retardancy improving effect may be insufficient, and when too large, the appearance of the molded product may be deteriorated.

{Release agent}
A release agent can be blended with the resin composition (A / B / C) of the present invention in order to improve the mold releasability during molding.

  Examples of the release agent include aliphatic carboxylic acids and alcohol esters thereof, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15000, polysiloxane silicone oil, and the like.

  Examples of the aliphatic carboxylic acid include saturated or unsaturated, linear or cyclic, aliphatic 1 to 3 carboxylic acids. Among these, monovalent or divalent carboxylic acids having 6 to 36 carbon atoms are preferable, and aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms are particularly 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, melissic acid, tetrariacontanoic acid, Examples include montanic acid, adipic acid, and azelaic acid.

  The aliphatic carboxylic acid component in the aliphatic carboxylic acid ester has the same meaning as the above-mentioned aliphatic carboxylic acid. On the other hand, the alcohol component of the aliphatic carboxylic acid ester includes a saturated or unsaturated, linear or cyclic monovalent or polyhydric alcohol. These may have a substituent such as a fluorine atom or an aryl group, and among them, a monovalent or polyvalent saturated alcohol having 30 or less carbon atoms is preferable, particularly 30 or less carbon atoms, a saturated aliphatic monovalent or Polyhydric alcohols are preferred.

  Specific examples of such alcohol components include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, and ditrimethylolpropane. And dipentaerythritol. The aliphatic carboxylic acid ester may contain an aliphatic carboxylic acid and / or alcohol as an impurity, and may be a mixture of a plurality of aliphatic carboxylic acid esters.

  Specific examples of the aliphatic carboxylic acid ester include beeswax (a mixture based on myricyl palmitate), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate, glycerin diester. Examples thereof include stearate, glycerin 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 15000 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. Moreover, these hydrocarbon compounds may be partially oxidized.

  Among these aliphatic hydrocarbons, paraffin wax, polyethylene wax, or partial oxides of polyethylene wax are preferable, and paraffin wax and polyethylene wax are particularly preferable. The number average molecular weight is preferably 200 to 5,000. These aliphatic hydrocarbons may be used alone or in combination of two or more at any ratio as long as the main component is within the above range.

  Examples of the polysiloxane silicone oil include dimethyl silicone oil, phenylmethyl silicone oil, diphenyl silicone oil, fluorinated alkyl silicone, and the like. These may be used alone or in combination of two or more.

  The compounding amount of the release agent may be appropriately selected and determined. However, if the amount is too small, the release effect is not sufficiently exhibited. Mold contamination may be a problem. Therefore, the compounding quantity of a mold release agent is 0.001-2 mass parts with respect to 100 mass parts of thermoplastic resins (C), and it is preferable that it is 0.01-1 mass part especially.

{Heat stabilizer / Antioxidant}
The resin composition (A / B / C) of the present invention is a heat stabilizer or a stabilizer for the purpose of suppressing yellowing that occurs during melt processing or long-term use at high temperatures, and further suppressing mechanical strength reduction. It is preferable to contain an antioxidant.

  As the heat stabilizer and the antioxidant, any conventionally known one can be used. As the heat stabilizer, a phosphorus compound is preferable, and as the antioxidant, a phenol compound is preferable, and these may be used in combination.

  The contents of the heat stabilizer and the antioxidant may be appropriately selected and determined. Usually, the total amount is 0.0001 to 0.00 with respect to 100 parts by mass of the resin composition (A / B / C). 5 parts by mass, preferably 0.0003 to 0.3 parts by mass, and particularly preferably 0.001 to 0.1 parts by mass. If the content of the heat stabilizer or antioxidant is too small, the effect is insufficient.

{Impact resistance improver}
In the present invention, an elastomer can be included as an impact resistance improver to improve impact strength. The elastomer is not particularly limited, but a multilayer structure polymer is preferable. As a multilayer structure polymer, the thing containing an alkyl (meth) acrylate type polymer is mentioned, for example. These multi-layered polymers include, for example, polymers produced by continuous multi-stage seed polymerization in which a polymer in a previous stage is sequentially coated with a polymer in a subsequent stage, and a basic polymer. As a structure, it is a polymer having an outermost core layer made of a polymer compound that improves the adhesion between the inner core layer, which is a crosslinking component having a low glass transition temperature, and the matrix of the composition. A rubber component having a glass transition temperature of 0 ° C. or lower is selected as a component that forms the innermost core layer of these multilayer polymers. These rubber components include rubber components such as butadiene, rubber components such as styrene / butadiene, rubber components of alkyl (meth) acrylate polymers, polyorganosiloxane polymers and alkyl (meth) acrylate polymers. Or a rubber component using these in combination. Furthermore, examples of the component that forms the outermost core layer include an aromatic vinyl monomer, a non-aromatic monomer, or a copolymer of two or more thereof. Examples of the aromatic vinyl monomer include styrene, vinyl toluene, α-methyl styrene, monochloro styrene, dichloro styrene, bromo styrene, and the like. Of these, styrene is particularly preferably used. Examples of non-aromatic monomers include alkyl (meth) acrylates such as ethyl (meth) acrylate and butyl (meth) acrylate, vinyl cyanide such as acrylonitrile and methacrylonitrile, and vinylidene cyanide.

  It is preferable that the compounding quantity of an impact resistance improving agent is 0.1-10 mass parts with respect to 100 mass parts of thermoplastic resins (C). If the amount is less than 0.1 parts by mass, the impact resistance improving effect by the impact modifier is insufficient, and if the amount exceeds 10 parts by mass, the molded product obtained by molding the resin composition (A / B / C) of the present invention. Appearance defect and heat resistance decrease occur. The lower limit of the amount is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and the upper limit of the amount is preferably 7.5 parts by mass or less, more preferably 5 parts by mass or less. The amount is particularly preferably 4 parts by mass or less.

{Reinforcing material}
The reinforcing material is used for improving the elastic modulus, strength, and deflection temperature under load. Here, as a reinforcing material, silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloon, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, Calcium sulfite, talc, clay, mica, glass fiber, flaky graphite, glass flake, glass beads, calcium silicate, montmorillonite, bentonite, aluminum powder, molybdenum sulfide, boron fiber, silicon carbide fiber, polyester fiber, polyamide fiber, boric acid Aluminum etc. can be illustrated.

  If the blending amount of the reinforcing material is too small, it is not possible to obtain a sufficient reinforcing effect due to the use of this, but if it is too large, the moldability tends to be impaired, so that the reinforcing material is a resin composition of the present invention ( (A / B / C) It is preferably used in a range of 100 parts by mass or less, particularly 70 parts by mass or less in 100 parts by mass.

<Manufacturing method>
As described above, the resin composition (A / B / C) of the present invention is provided as a dry blend, a pellet mixture, a melt-kneaded product, and a pelletized product thereof. As described above, the method for obtaining pellets by melt-kneading is, as described above, kneaded the above components with various kneaders, such as uniaxial and multi-axial kneaders, Banbury mixers, rolls, Brabender plastograms, etc., and then cooled. Add the above components to a solidifying method or a suitable solvent such as hydrocarbons such as hexane, heptane, benzene, toluene, xylene and their derivatives, and dissolve the components, or dissolve and dissolve the insoluble components. The solution mixing method etc. which mix in a state are used. The melt-kneading method is preferable from the industrial cost, but is not limited thereto. In melt kneading, it is preferable to use a single-screw or twin-screw extruder.

[Resin molding for electromagnetic wave shield]
The method for producing the resin molded article for electromagnetic wave shielding of the present invention by forming the resin composition (A / B / C) of the present invention is not particularly limited, and is generally used for thermoplastic resin compositions. For example, molding methods such as injection molding, hollow molding, extrusion molding, sheet molding, thermoforming, rotational molding, and lamination molding can be applied. Among these, injection molding is common for the production of resin molded products for electromagnetic wave shielding.

  Although there is no restriction | limiting in particular about the application field of the molded article of this invention, For example, housing uses and connectors, such as an OA apparatus, AV apparatus, a measurement apparatus, a transport apparatus, a communication apparatus, a radar apparatus, in which electromagnetic shielding properties are requested | required And packaging materials.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples, and is appropriately within a range that can meet the gist of the present invention. It is also possible to carry out with modification, and they are all included in the technical scope of the present invention.
In the following examples, the following components were used.

(A) Resin for impregnation (A-1) Polycarbonate resin: Poly-4,4-isopropylidenediphenyl carbonate, manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: Iupilon (registered trademark) H-4000FN, viscosity average molecular weight 16 1,000, melting temperature 144 ° C. (hereinafter abbreviated as “PC”)
(A-2) Aromatic polycarbonate oligomer: A granular aromatic polycarbonate oligomer having an average polymerization degree of 7 obtained from bisphenol A and phosgene by an interfacial polycondensation method, manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: Iupilon (registered) Trademark) AL071, viscosity average molecular weight 6000 (hereinafter abbreviated as “PC oligomer”)
(A-3) Polymerized fatty acid polyamide: softening temperature 170 ° C., melt viscosity 1600 MPa · s (JIS K 6862, measurement temperature 250 ° C.) (hereinafter abbreviated as “polyamide”)

(B) Conductive fiber (B-1) Carbon fiber: PAN-based carbon fiber having an average fiber diameter of 7 μm, about 24,000 fiber bundles (B-2) SUS fiber: SUS fiber having an average fiber diameter of 12 μm, about 7 , 000 fiber bundles (B-3) Copper-coated aramid fibers: Copper-coated meta-aramid fibers having an average fiber diameter of 15 μm (copper coating thickness of 0.8 μm, approximately 6000 fiber bundles).

(C) Thermoplastic resin (C-1) Polycarbonate resin pellets: Poly-4,4-isopropylidene diphenyl carbonate, manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: Iupilon (registered trademark) S-3000, viscosity average molecular weight 21, 000 (hereinafter abbreviated as “PC pellet”)
(C-2) Phosphorus flame retardant-added polycarbonate resin pellets: Poly-4,4-isopropylidenediphenyl carbonate (Mitsubishi Engineering Plastics) with a viscosity average molecular weight of 22,000 and phosphorus flame retardant (Daihachi Chemical Co., Ltd.) , Trade name PX-200) obtained by mixing 10% by mass (hereinafter abbreviated as “P / PC pellet”).
(C-3) Phosphorus flame retardant-added polycarbonate and ABS resin alloy resin pellets: Poly-4,4-isopropylidenediphenyl carbonate (Mitsubishi Engineering Plastics) having a viscosity average molecular weight of 24,000 and phosphorus flame retardant ( A composition manufactured by ADEKA, trade name FP-700) 15% by mass, ABS resin 20% by mass, talc 15% by mass (hereinafter abbreviated as “P / PC / ABS pellet”)

(D) Flame retardant: resorcinol bis (dixylenyl phosphate) (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: PX200)
(E) Impact resistance improver: butadiene / alkyl acrylate / alkyl methacrylate copolymer (manufactured by Kureha Chemical Industry Co., Ltd., trade name: Paraloid (registered trademark) EXL2603)
(F) Anti-drip agent: mixed powder of methyl methacrylate / butyl acrylate copolymer and tetrafluoroethylene polymer (Mitsubishi Rayon Co., Ltd., trade name: Metabrene (registered trademark) A-3800)
(G) Mold release agent: higher fatty acid pentaerythritol ester (manufactured by Henkel Japan, trade name: Roxyol (registered trademark) VPG861)
(H) Stabilizer (H-1) Tris (2,4-di-t-butylphenyl) phosphite (manufactured by ADEKA, trade name: ADK STAB (registered trademark) 2112) (hereinafter referred to as “stabilizer-1”) (Abbreviated)
(H-2) Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (manufactured by Ciba, trade name: IRGANOX (registered trademark) 1076) (hereinafter, "stabilizer-2" Abbreviated)

[Examples I-1 to I-4]
An impregnating resin comprising PC and PC oligomers blended in the proportions shown in Table 1 and fed from an extruder connected to the crosshead die while drawing the predetermined continuous fiber bundle shown in Table 1 through the crosshead die Was impregnated as a molten mixture. From the die exit, pultrusion was performed to obtain a strand, which was cut into a length of 6 mm to obtain pellets (A / B) (pellets 1 to 4), respectively.
The extrusion results at this time were evaluated from the appearance of the obtained pellets, etc., and are shown in Table 1. Further, with respect to the impregnating resin, measured values of the viscosity average molecular weight are shown in Table 1.

[Comparative Examples I-1 to I-2]
In Example I-1, in place of a total of 45 parts by weight of the impregnating resin composed of PC and PC oligomer, only 45 parts by weight of impregnating resin (Comparative Example I-1) and only 45 parts by weight of PC oligomer were impregnated, respectively. Pellets (A / B) (pellets 5, 6) were obtained in exactly the same manner as in Example I-1, except that the resin for use (Comparative Example I-2) was used.
The extrusion results and viscosity average molecular weight at this time are shown in Table 1.

[Comparative Examples I-3 to I-5]
In Examples I-2 to I-4, each of Examples I-2 to I- was used except that the same amount of polyamide as the total amount of the impregnating resin was used instead of the impregnating resin composed of PC and PC oligomer. In the same manner as in No. 4, pellets (A / B) (pellets 7 to 9) were obtained.
The extrusion results and viscosity average molecular weight at this time are shown in Table 1.

As shown in Examples I-1 to I-4 in Table 1, when the impregnating resin is a polycarbonate resin having a viscosity average molecular weight of 7,000 to 13,000, cracks occur in the pellets while easily impregnating the fibers. (Indicated in circles in Table 1).
On the other hand, as in Comparative Example I-1, in the case of a polycarbonate resin having a viscosity average molecular weight of 16,000, it was difficult to impregnate the fibers. On the other hand, as in Comparative Example I-2, in the case of a polycarbonate oligomer having a viscosity average molecular weight of 6,000, although the fibers were impregnated, the pellets were broken because the resin itself was not strong.
In addition, as in Comparative Examples I-3 to I-5, when the impregnation resin was a polymerized fatty acid polyamide, the fibers were easily impregnated, and the pellets did not crack. Thus, it is unsuitable for blending with polycarbonate or polycarbonate / ABS resin alloy.

[Examples II-1 to II-7 and Comparative Examples II-1 to II-4]
The pellets 1 to 4 and 7 to 9 obtained in Examples I-1 to I-4 and Comparative Examples I-3 to I-5 were respectively converted into thermoplastic resin components (PC pellets or P / PCs) shown in Table 2. / ABS pellets and other additives) and uniformly mixed at the ratio shown in Table 2, using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., SH100, mold clamping force 100T), resin temperature (measured temperature of purge resin) ): 300 ° C., mold temperature: 110 ° C., injection pressure: 147 MPa, mold: injection molding under the conditions of length 100 mm, width 100 mm, thickness 2 mm to obtain a resin molded body for electromagnetic wave shielding.
The obtained injection molded article was measured for surface appearance, electromagnetic shielding properties and impact strength as follows, and the evaluation results are shown in Table 2.

<Surface appearance>
By visually observing the molded product, the case where the occurrence of silver on the surface was recognized even a little was indicated as x, and the case where no silver was observed was indicated as ◯.

<Electromagnetic wave shielding>
The electromagnetic wave shielding property (unit: dB) of the molded body at a frequency of 500 MHz was measured using an electromagnetic wave shielding material evaluator (manufactured by Advantest Co., Ltd., TR17301A).

<Impact strength>
In accordance with JIS K7111 (ISO 179), an injection-molded test piece (without notch) having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm was cut out from the molded body, and Charpy impact tester (made by Toyo Seiki Seisakusho, Charpy impact tester) ) Was applied, edgewise impact was applied, impact energy at the time of fracture was measured, and impact strength (unit: kJ / m ² ) calculated from the measured value was displayed.

[Example II-8 and Comparative Example II-5]
The pellets 4 and 9 obtained in Example I-4 and Comparative Example I-5 were mixed with the thermoplastic resin and flame retardant shown in Table 2 at the ratio shown in Table 2, respectively, and a single screw extruder (Tanabe) The mixture was kneaded and extruded into pellets by VS40) manufactured by Kikai Co., Ltd. The pellets were injection molded under the same conditions as in Example II-1 and evaluated in the same manner. The results are shown in Table 2.

As shown in Table 2 above, no silver was observed on the surfaces of the molded bodies of Examples II-1 to II-8, which was good. On the other hand, it turned out that silver by decomposition | disassembly of a polycarbonate generate | occur | produced on the surface of the molded object of Comparative Examples II-1 to II-5, surface appearance deteriorates remarkably, and cannot be used as a product.
Moreover, the evaluation of the electromagnetic wave shielding properties of the molded products of Examples II-1 to II-8 was good, and the impact strength was also good. On the other hand, the electromagnetic wave shielding properties of the molded bodies of Comparative Examples II-1 to II-5 were good, but it was found that the impact strength was inevitably lowered.

As shown in Tables 1 and 2, if the polycarbonate resin adjusted to have the molecular weight of the present invention is used as the fiber impregnating resin, the conductive fiber can be sufficiently impregnated to maintain sufficient strength. Because it was possible, it could be pelletized.
Since this product does not use polymerized fatty acid polyamide as in the past, it prevents the deterioration of the strength of the molded product obtained by mixing it with polycarbonate resin and injection molding, or the molded product obtained by injection molding after melt-kneading. However, the surface appearance can be kept good, and sufficient performance can be imparted with respect to electromagnetic wave shielding properties.

[Examples III-1 to III-3 and Reference Examples III-1 to III-3]
Except for using the predetermined continuous fiber bundle shown in Table 3 and the impregnating resin composed of PC and PC oligomer blended in the ratio shown in Table 3, the pultruded strand was cut into the length shown in Table 3. In the same manner as in Example I-1, pellets (A / B) (pellets 10 to 15) were obtained.

  The extrusion results at this time were evaluated from the appearance of the obtained pellets, etc., and are shown in Table 3. For the impregnating resin, the measured values of the viscosity average molecular weight are shown in Table 3.

[Examples IV-1 to IV-7 and Reference Examples IV-1 to IV-7]
The pellets 10-12 and 13-15 obtained in Examples III-1 to III-3 and Reference Examples III-1 to III-3 were respectively converted into thermoplastic resin components (P / PC pellets or P / PC shown in Table 4). / ABC pellets) and mold release agent in the proportions shown in Table 4 and after being uniformly dispersed by a tumbler, the mixture was transferred to a single screw extruder (single screw extruder VS48-28 type extruder manufactured by Tanabe Plastics Machinery). The mixture was melted at a cylinder temperature of 290 ° C., kneaded at a screw rotation speed of 80 rpm, and cut into a predetermined pellet length shown in Table 4 with a pelletizer to obtain a resin composition for electromagnetic wave shielding.

  Using the obtained pellets, using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., SH100, mold clamping force 100T), resin temperature (measured temperature of purge resin): 300 ° C, mold temperature: 60 ° C, Injection molding was performed under the conditions of injection pressure: 147 MPa, mold: 100 mm long, 100 mm wide, and 2 mm thick to obtain an electromagnetic wave shielding resin molded body.

  Stable productivity at the time of producing pellets of the resin composition for electromagnetic wave shielding and meterability at the time of injection molding were evaluated as follows, and the results are shown in Table 4. The obtained injection-molded product was measured for electromagnetic shielding properties as follows, and the evaluation results are shown in Table 4.

<Stable productivity>
When producing pellets of the resin composition for electromagnetic wave shielding by melting and kneading, the case where fibers are entangled and clogged in the extruder within 1 hour after the start of extrusion is designated as “X”, and is not clogged and stable. The case where production was possible was evaluated as “◯”.

<Measureability during injection molding>
When injection molding pellets of resin composition for electromagnetic wave shielding, the case where the pellets cannot be measured without biting into the screw, or when the measurement time exceeds 8 seconds and a remarkably long molding cycle is required is evaluated as “X”. When the measurement time was 8 seconds or less and the measurement was possible without any problem, it was evaluated as “◯”.

<Electric field shielding>
The electric field shielding property at a frequency of 200 MHz was measured using an EMI shield measuring device manufactured by Advantest.

From the results shown in Table 4, the following can be understood.
The resin compositions for electromagnetic wave shielding of Examples IV-1 to IV-7 are excellent in the balance of extrusion productivity, molding productivity, and electromagnetic wave shielding properties.
In Reference Examples IV-1 and 2, the length of the fiber / resin composite composition pellets is sufficient as 6 mm, but the length of the resin composition pellets for electromagnetic wave shielding is as short as about 1.8 mm. Compared with 1 and 3, the electromagnetic shielding properties are each reduced by about 5 dB. On the contrary, in Reference Example IV-4, the length of the resin composition pellet for electromagnetic wave shielding was sufficient as 6 mm, but since the length of the fiber / resin composite composition pellet was as short as 2 mm, the electric field shielding property was greatly deteriorated. In Reference Example IV-5, both the fiber / resin composite composition pellet and the electromagnetic wave shielding resin composition pellet are shorter than those of the present invention. Thus, it can be seen that sufficient electromagnetic wave shielding properties cannot be obtained unless the length of the fiber / resin composite composition pellet and the length of the electromagnetic wave shielding resin composition pellet are both within the preferred range of the present invention. Reference Example IV-7, in which both the fiber / resin composite composition pellet and the electromagnetic wave shielding resin composition pellet are short, has very poor electromagnetic wave shielding properties.
Further, as in Reference Example IV-3, if the pellet length of the resin composition for electromagnetic wave shielding is increased, the measurement time at the time of injection molding becomes longer, and the molding cycle is remarkably increased, so that the production cost of the molded product is increased. There may be a problem that it cannot be measured and cannot be molded.
Further, as in Reference Example IV-6, when the length of the fiber / resin composite composition pellet exceeds 10 mm, stable production is difficult because the discharge rate fluctuates and strand breaks frequently occur. As the time elapses, the fibers gradually become entangled in the extruder. Even if a resin composition for electromagnetic wave shielding is obtained, the electromagnetic wave shielding property of Example IV-5 is not significantly changed compared with the value of Example IV-1, and the length of the fiber / resin composite composition It can be seen that there is no advantage of making the length longer than 10 mm.

  ADVANTAGE OF THE INVENTION According to this invention, it can provide the electromagnetic wave shielding resin molding which has the outstanding electromagnetic wave shielding effect, was excellent in the external appearance, and was improved in impact strength. This electromagnetic shielding resin molded product can be suitably used in a wide range of industrial fields that require shielding of electromagnetic waves, including housings for electronic devices, and the industrial effects that it exhibits are exceptional.

Claims (19)

A long fiber bundle of at least one conductive fiber (B) selected from metal fibers, carbon fibers and metal-coated non-metallic fibers, and a polycarbonate resin (A) having a viscosity average molecular weight of 7,000 to 13,000,
The fiber diameter of the long fiber bundle is 1 to 50 μm,
A fiber / resin composite composition pellet for electromagnetic wave shielding, wherein the long fiber bundle is impregnated with the polycarbonate resin (A).   The polycarbonate resin (A) is obtained by blending 50 to 300 parts by mass of a polycarbonate oligomer having a viscosity average molecular weight of 1000 to 10,000 with respect to 100 parts by mass of a polycarbonate resin having a viscosity average molecular weight of 14,000 to 18,000. The fiber / resin composite composition pellet for electromagnetic wave shielding according to claim 1.   3. The fiber / resin composite composition for electromagnetic wave shielding according to claim 1 or 2, wherein the long fiber bundle of the conductive fibers (B) is formed by converging 5,000 to 35,000 long fibers. pellet.   4. The electromagnetic wave shielding fiber / resin composite composition pellet according to claim 1, wherein the length of the pellet is 2 to 15 mm.   The length of a pellet is 4-10 mm, The fiber / resin composite composition pellet for electromagnetic wave shields of Claim 4 characterized by the above-mentioned.   6. The electromagnetic shielding material according to claim 1, wherein the conductive fiber (B) is at least one metal fiber selected from stainless steel fiber, aluminum fiber, copper fiber and brass fiber. Fiber / resin composite composition pellets.   The metal-coated non-metallic fiber has a surface of at least one non-metallic fiber selected from glass fiber, aramid fiber, polyester fiber, and carbon fiber, gold, silver, copper, nickel, aluminum, cobalt, iron, zinc, tin And an electromagnetic shielding fiber / resin composite composition pellet according to any one of claims 1 to 6, which is coated with at least one metal selected from an alloy containing at least one of these metals. .   The continuous bundle of conductive fibers (B) is pellets obtained by passing through the impregnation treatment zone of the polycarbonate resin (A) and further cutting the pellets. Fiber / resin composite composition pellets for electromagnetic wave shielding.   Content of the said electroconductive fiber (B) is 20-80 mass%, The fiber / resin composite composition pellet for electromagnetic wave shields in any one of the Claims 1 thru | or 8 characterized by the above-mentioned.   An electromagnetic shielding resin composition comprising a thermoplastic resin (C) and the electromagnetic shielding fiber / resin composite composition pellet according to any one of claims 1 to 9.   The content of the fiber / resin composite composition pellet according to any one of claims 1 to 9 with respect to 100 parts by mass of the thermoplastic resin (C) is 3 to 300 parts by mass. The resin composition for electromagnetic wave shielding as described in 2.   The pellet mixture obtained by mixing the pellet of the thermoplastic resin (C) and the fiber / resin composite composition pellet for electromagnetic wave shielding according to any one of claims 1 to 9. 11. A resin composition for electromagnetic wave shielding according to 11.   The melt-kneaded product obtained by melt-kneading the thermoplastic resin (C) and the fiber / resin composite composition pellet for electromagnetic wave shielding according to any one of claims 1 to 9. The resin composition for electromagnetic wave shielding as described in 2.   10. A pellet formed by mixing and pelletizing the thermoplastic resin (C) and the fiber / resin composite composition pellet for electromagnetic wave shielding according to any one of claims 1 to 9. 11. A resin composition for electromagnetic wave shielding according to 11.   The length of the said pellet is 2.5-15 mm, The resin composition for electromagnetic wave shields of Claim 14 characterized by the above-mentioned.   The length of the said pellet is 5.1-13 mm, The resin composition for electromagnetic wave shields of Claim 15 characterized by the above-mentioned.   The resin composition for electromagnetic wave shielding according to any one of claims 10 to 16, wherein the thermoplastic resin (C) contains an aromatic polycarbonate resin.   The electromagnetic wave according to claim 17, wherein the thermoplastic resin (C) is an aromatic polycarbonate resin having a viscosity average molecular weight of 14,000 to 30,000 or an alloy of the aromatic polycarbonate resin and an ABS resin. Shielding resin composition.   19. A resin molded body for electromagnetic wave shielding obtained by molding the resin composition for electromagnetic wave shielding according to any one of claims 10 to 18.