JPH0564664B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a metal fiber-containing resin composition, and more specifically, a metal fiber-containing resin composition suitable for electromagnetic shielding materials, antistatic materials, etc. Regarding. [Prior Art and its Problems] In recent years, in the field of housings for electronic devices, OA office processing equipment, home appliances, etc., products are increasingly being made of synthetic resin. However, since synthetic resins transmit electromagnetic waves emitted from electronic devices and the like, electromagnetic interference such as generation of noise and malfunction of elements and the like occurs. As a method to prevent this electromagnetic interference, by blending metal fibers etc. into the resin material,
It is known to mold a resin composition with conductivity and to make a housing from the conductive resin composition. Specifically, in Special Publication No. 58-14457,
A resin composition made by blending metal fibers and metal powder with a thermoplastic resin has been disclosed, and Japanese Patent Application Laid-Open No. 1986-
Publication No. 189142 discloses a resin composition made by blending metal fibers and carbon fibers with a thermoplastic resin. However, since such a resin composition only contains metal fibers, there is a problem in that the metal fibers have poor uniform dispersibility and cannot sufficiently exhibit a conductive effect. In order to improve conductivity, it is possible to increase the amount of metal fiber blended, but this may cause deterioration in the moldability of the resin composition, decrease in mechanical strength such as impact resistance of the molded product, poor appearance, or
Problems such as wear and damage to molds and molding machines occur. On the other hand, a molding material using a titanate coupling agent has been proposed in order to improve the uniform dispersion of metal fibers (Japanese Patent Laid-Open No. 18314/1983), but it has the problem of insufficient electrical conductivity. It was hot. [Object of the Invention] This invention has been made based on the above circumstances. That is, an object of the present invention is to maintain various excellent properties inherent in synthetic resins such as mechanical strength, have excellent conductivity, and be suitable for electromagnetic shielding materials or antistatic materials, and further, It is an object of the present invention to provide a metal fiber-containing resin composition that has excellent moldability and does not cause wear or damage to molding machines or the like. [Means for achieving the above object] In order to achieve the above object, as a result of extensive research by the present inventor, the mechanical The present invention was achieved by discovering that a resin composition having excellent strength, moldability, and appearance of a molded product as well as having excellent conductivity can be obtained. The outline of this invention for achieving the above object is as follows:
Containing a thermoplastic resin, a surfactant selected from the group consisting of a nonionic surfactant, an amphoteric surfactant and a cationic surfactant, and a metal fiber,
When the total of the thermoplastic resin, the surfactant, and the metal fiber is 100% by weight, the blending amount of the surfactant is 0.01 to 2% by weight,
The metal fiber-containing resin composition is characterized in that the amount of the metal fibers is 0.5 to 15% by weight. Examples of the thermoplastic resin include general resins such as polyolefin resin, vinyl chloride resin and its copolymer resin, vinylidene chloride resin, polystyrene and its copolymer resin, polyamide resin, polyacetal, polycarbonate, thermoplastic polyester resin, Examples include engineering plastics such as polyarylene sulfide, polyphenylene oxide, noryl resin, and polysulfone. As the polyolefin resin, for example,
High density polyethylene, medium and low density polyethylene,
Examples include polyethylene such as linear low-density polyethylene, polypropylene such as isotactic polypropylene, syndiotactic polypropylene, and atactic polypropylene, polybutene, and 4-methylpentene-1 resin. propylene copolymer,
Copolymers with olefins such as ethylene-vinyl acetate copolymers, ethylene-vinyl chloride copolymers, and propylene-vinyl chloride copolymers can also be used. Examples of the vinyl chloride copolymer resin include vinyl chloride-vinyl acetate resin, vinyl chloride-vinyl acetate resin, and vinyl chloride-vinyl acetate resin.
Examples include vinylidene chloride copolymer resin and vinyl chloride-acrylonitrile copolymer resin. Examples of the polystyrene copolymer resin include ABS resin and SAN resin. Examples of the polyamide resin include nylon 6, nylon 8, nylon 11, nylon 66, and nylon 610. The polyacetal may be a single polymer or a copolymer. Examples of the polycarbonate include polycarbonate obtained from bisphenol A and phosgene, polycarbonate obtained from bisphenol A and diphenyl carbonate, and the like. Examples of the thermoplastic polyester resin include polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate. Examples of the polyarylene sulfide include polyphenylene sulfide. Since the metal fiber-containing resin composition according to the present invention is subjected to molding, the thermoplastic resin may be selected from the various thermoplastic resins as long as it has a moldable molecular weight. can be used. The above various thermoplastic resins may be used alone, or two or more types may be mixed and used as a polymer blend. Among the various thermoplastic resins mentioned above, polystyrene and copolymer resins thereof are preferred. More preferred are polybutadiene, ABS resin, SBS
Polystyrene (so-called impact-resistant polystyrene) in which soft component particles are dispersed is obtained by dissolving or mixing 2 to 20% by weight of rubber such as resin, MBS resin, or NAS resin in styrene monomer and polymerizing the styrene monomer. ), and ABS resin. The surfactant selected from the group consisting of nonionic surfactants, amphoteric surfactants, and cationic surfactants is a reagent having a hydrophilic group and a lipophilic group in its molecule, and its action is Although it is not clear, it is thought that this improves the affinity between the thermoplastic resin and the metal fiber. As the nonionic surfactant, for example,
Ethers such as alkyl polyoxyethylene ether, alkylaryl polyoxyethylene ether, alkylaryl formaldehyde condensation polyoxyethylene ether, glycerin ether and its polyoxyethylene ether, and block polymers having polyoxypropylene as a lipophilic group;
Polyoxyethylene ether of propylene glycol ester, polyoxyethylene ether of glycerin ester, polyoxyethylene ether of sorbitan ester, ester of sorbitol polyoxyethylene ether, ester of glycerin ether, ester of alkyl polyoxyethylene ether, copolymer Ether esters such as polyoxyethylene ether ester; polyoxyethylene fatty acid ester, glycerin ester such as stearic acid monoglyceride, stearic acid triglyceride and lauric acid monoglyceride, sorbitan ester such as sorbitan fatty acid ester, dihydric alcohol ester, sucrose ester, etc. Esters; fatty acid alkanolamide, polyoxyethylene fatty acid amide, ester of alkanolamine, polyoxyethylene alkylamine, tertiary amide (excluding primary amide and secondary amide) such as polyoxyethylene amide, amine oxide, etc. Nitrogen-containing type is mentioned. Examples of the amphoteric surfactants include betaines such as alkylbetaines, carboxybetaines and sulfobetaines, aminocarboxylic acid salts such as alkylalanines, and imidazoline derivatives such as alkylimidazolines. Examples of the cationic surfactant include aliphatic primary amine salts, aliphatic secondary amine salts,
Aliphatic tertiary amine salts, quaternary ammonium salts such as quaternary ammonium chloride, quaternary ammonium sulfate and quaternary ammonium nitrate; hydroxy ammonium salts, ether ammonium salts; aromatic quaternary salts such as benzalkonium salts, benzethonium salts; Examples include ammonium salts, pyridinium salts, and imidazolinium salts. The surfactants selected from the group consisting of nonionic surfactants, amphoteric surfactants, and cationic surfactants may be used alone or in combination of two or more. Good too. Among the surfactants selected from the group consisting of nonionic surfactants, amphoteric surfactants and cationic surfactants, nonionic surfactants and amphoteric surfactants are preferred, particularly glycerin fatty acid esters, betaine and sulfuric acid. Ester salts are preferred, and more preferred are stearic acid monoglycerides, alkyl betaines and alkyl sulfates. The metal fibers in this invention are commonly known conductive metal fibers, such as metals, alloys,
Fibers of conductive metal compositions and metallized glass fibers that can be substituted for the fibers, ie, glass fibers whose surfaces are plated or coated with metal. As such, various metal fibers such as stainless steel fibers, aluminum fibers, copper fibers, nickel fibers, silicon steel fibers, brass fibers, tin bronze fibers, phosphor bronze fibers, Fernico fibers, permalloy fibers, and nickel, cobalt fibers, etc. ,
Mention may be made of various metallized glass fibers plated or coated with various metals such as aluminum, copper, etc. Among these metal fibers,
Stainless steel fibers and nickel-plated glass fibers are preferred, and stainless steel fibers are particularly preferred. The metal fibers have a length of 3 to 10 mm, particularly 4 mm.
~8mm is preferred, and the aspect ratio is 200
Above, it is particularly preferable that it is 400 to 900. If the length is less than 3 mm, the resulting resin composition may have insufficient conductivity, and if it exceeds 10 mm, it may become difficult to knead during compounding or cause wear of the kneading screw. be. Aspect ratio is 200
If the amount is less than 1, the conductivity may not be improved sufficiently unless the amount of metal fibers is increased. The metal fiber can be manufactured by a method such as a melt spinning method, a stretching method, a wire drawing method, an extrusion method, or a cutting method. Further, the metallized glass fiber can be manufactured by, for example, plating, coating, coating, depositing, vapor depositing, or the like a metal on the surface of a glass fiber manufactured by a known method. The metal fibers are degreased or pickled before being blended with the thermoplastic resin and the surfactant,
It is preferable to treat it with a convergence agent, and it is desirable to use it as a convergence body. For example, a range of 500 to 15,000 is suitable. Examples of degreasing include solvent degreasing, immersion degreasing,
These include alkaline degreasing and surfactant degreasing. The sizing agent used in the sizing agent treatment is not particularly limited as long as it is soluble in a solvent, and includes thermoplastic resins such as polyester resin, ABS resin, polystyrene resin, and polyolefin resin. Moreover, a tackifier such as a terpene resin can also be used in combination, if necessary. As a preferred pretreatment method, after degreasing, the bundle of metal fibers is immersed in a solution prepared by dissolving a thermoplastic resin and a tackifier in a hydrocarbon solvent, and then, after drying, the metal fibers are cut into a predetermined length. An example of this is cutting at the right angle. The various metal fibers mentioned above may be used alone or in combination of two or more. In the metal fiber-containing resin composition according to this invention,
the thermoplastic resin and the nonionic surfactant;
It should be noted that the surfactant selected from the group consisting of amphoteric surfactants and cationic surfactants and the metal fibers are contained in a specific blending ratio. That is, this metal fiber-containing resin composition contains 100% by weight of the total of the thermoplastic resin, a surfactant selected from the group consisting of nonionic surfactants, amphoteric surfactants, and cationic surfactants, and metal fibers. The amount of the surfactant selected from the group consisting of nonionic surfactants, amphoteric surfactants and cationic surfactants is 0.01 to 2% by weight, preferably 0.1 to 1.0% by weight. The blending amount of the metal fiber is 0.5 to 15% by weight, preferably 2 to 10% by weight, and the blending amount of the thermoplastic resin is the remaining amount (83 to 15% by weight).
99.5% by weight, preferably 89-98% by weight). If the amount of the surfactant selected from the group consisting of nonionic surfactants, amphoteric surfactants, and cationic surfactants is less than 0.01% by weight, the dispersion of metal fibers will be poor, and the metal fiber-containing It is not possible to impart sufficient electrical conductivity to the resin composition, and the mechanical strength may decrease. On the other hand, if the blending amount is more than 2% by weight, the resin will slip during kneading, making kneading difficult. If the blending amount of the metal fiber is less than 0.5% by weight, sufficient conductivity cannot be imparted to the metal fiber-containing resin composition even though it is called a metal fiber-containing resin composition. 15% by weight
If the amount exceeds , the conductivity will not improve to the extent equivalent to the blended amount, and moreover, the moldability will decrease, and even if a molded product is obtained, the impact resistance of the molded product will decrease and the specific gravity will increase. Put it away. This metal fiber-containing resin composition may contain colorants, flame retardants, antioxidants, ultraviolet absorbers, plasticizers, inorganic fillers, heat stabilizers, etc., as necessary, as long as they do not impede the effects of the present invention. Various additives can be added and blended. In addition, since this metal fiber-containing resin composition already contains a surfactant selected from the group consisting of a nonionic surfactant, an amphoteric surfactant, and a cationic surfactant, an antistatic agent is added as an additive. It also has antistatic properties without the need for further blending. Further, as the coloring agent, a sparingly soluble azo dye,
Examples include red colorant, cadmium yellow, cream yellow, titanium white, etc. Examples of the flame retardant include inorganic antimony oxide, zirconium oxide, etc., and organic phosphoric acid ester, tricresyl phosphate, etc. As the antioxidant, triazole-based, salicylic acid-based, and acrylonitrile-based antioxidants are used. Furthermore, examples of the plasticizer include phthalic acid diester, butanol diester, phosphoric acid diester, and the like. Examples of the inorganic filler include carbonates such as calcium carbonate, magnesium carbonate, and dolomite, sulfates such as calcium sulfate and magnesium sulfate, sulfites such as calcium sulfite, talc, clay, mica, asbestos, glass fiber,
Glass beads, calcium silicate, montmorillonite, bentonite and other silicates, silicon carbide,
Examples include ceramics such as silicon nitride, their whiskers, carbon black, graphite, carbon fibers, etc., and these inorganic fillers can be used alone or in a mixture of two or more of the above inorganic fillers. can. Among the various inorganic fillers, carbonates, sulfates, and silicates are preferred, and calcium carbonate, barium sulfate, talc, mica, and zinc powder are particularly preferred. The calcium carbonate and barium sulfate are
In addition to improving the surface smoothness and gloss of a molded article made of this metal fiber-containing resin composition, it is also possible to improve the heat resistance and abrasion resistance of the molded article. The metal fiber-containing resin composition according to the present invention includes the thermoplastic resin, the nonionic surfactant,
It can be produced by blending the metal fibers with a surfactant selected from the group consisting of amphoteric surfactants and cationic surfactants, and further blending the various additives as necessary. The method of blending is not particularly limited; for example, dry blending may be performed using a mixer such as a Henschel mixer, a Banbury mixer,
Melt kneading may be performed using a roll mill, screw type extruder, or the like. The various additives mentioned above may be added during this kneading. In addition, the drawn metal fibers are converged with a convergence agent,
Next, after being brought into contact with a surfactant, the metal fibers may be cut into predetermined dimensions and mixed and kneaded with a thermoplastic resin. Alternatively, a thermoplastic resin and a surfactant selected from the group consisting of a nonionic surfactant, an amphoteric surfactant, and a cationic surfactant are mixed and kneaded to produce a masterbatch, and a metal of a predetermined size is added to the masterbatch. The fibers may be dry blended. In addition, after converging the metal fibers with a convergence agent containing a surfactant selected from the group consisting of a nonionic surfactant, an amphoteric surfactant, and a cationic surfactant, the metal fibers are cut into predetermined dimensions and then combined with a thermoplastic resin. It may be mixed or kneaded. The metal fiber-containing resin composition thus obtained is molded into various molded products by various molding methods such as injection molding, cast molding, extrusion molding, and press molding. The metal fiber-containing resin composition obtained in this way has improved conductivity without reducing the mechanical strength of the molded product, so it is suitable in the industrial material field as an electromagnetic shielding material and an antistatic material. It can be used and is useful. [Effects of the Invention] According to the present invention, a thermoplastic resin, a surfactant selected from the group consisting of a nonionic surfactant, an amphoteric surfactant, and a cationic surfactant, and metal fibers are mixed in a specific ratio. Since it is blended, the following effects can be achieved. (1) Since the metal fibers are uniformly dispersed, this metal fiber-containing resin composition has excellent conductivity even if the amount of the metal fibers is small, and has excellent electromagnetic shielding properties and antistatic properties. (2) Since the amount of metal fibers may be small, the processability up to this metal fiber-containing resin composition, as well as the moldability and processing when obtaining various molded products from this metal fiber-containing resin composition, are improved. Furthermore, the mechanical properties such as the mechanical strength of the various moldability obtained are maintained at high levels, and the appearance of the molded products is excellent. (3) Since only a small amount of metal fiber is blended, this metal fiber-containing resin composition is lightweight. (4) Therefore, this metal fiber-containing resin composition is very useful as a material for preventing static electricity or shielding electromagnetic waves emitted from electronic devices and various elements. [Examples] Next, the present invention will be explained in more detail by showing examples and comparative examples of the present invention. (Examples 1 to 8, Comparative Examples 1 to 3) An interface selected from the group consisting of thermoplastic resins of the types shown in the footnotes of Table 1, nonionic surfactants, amphoteric surfactants, and cationic surfactants. The activator, metal fibers, etc. were dry blended in the proportions shown in Table 1 and injection molded to form test pieces. This test piece was evaluated for Izot impact strength, volume resistivity, and EMI shielding properties. In addition, the Izotsu impact strength is based on ASTM D256 (notched), the measurement of volume resistivity is based on the Japan Rubber Association standard SRIS2301, and the EMI shielding property is based on the Takeda Riken method and is electromagnetic shielding at 500MHz. This is an evaluation of gender. The results are shown in Table 1. 【table】

Claims (1)

[Scope of Claims] 1. A thermoplastic resin containing a thermoplastic resin, a surfactant selected from the group consisting of a nonionic surfactant, an amphoteric surfactant, and a cationic surfactant, and a metal fiber, When the total of the resin, the surfactant, and the metal fiber is 100% by weight,
A metal fiber-containing resin composition, wherein the surfactant is blended in an amount of 0.01 to 2% by weight, and the metal fiber is blended in an amount of 0.5 to 15% by weight. 2. The metal fiber-containing resin composition according to claim 1, wherein the surfactant is a nonionic surfactant and/or an amphoteric surfactant. 3. The metal fiber-containing resin composition according to claim 1 or 2, wherein the thermoplastic resin is impact-resistant polystyrene and/or ABS resin. 4. The metal fiber-containing resin composition according to any one of claims 1 to 3, wherein the metal fiber is a metal fiber having a length of 3 to 10 mm and an aspect ratio of 200 or more. 5. The metal fiber-containing resin composition according to any one of claims 1 to 4, wherein the metal fibers are stainless steel fibers and/or metallized glass fibers. 6. The metal fiber-containing resin composition according to claim 5, wherein the metallized glass fiber is a metal-plated glass fiber. 7. The metal fiber-containing resin composition according to claim 5, wherein the metallized glass fiber is a nickel-plated glass fiber.