JPS61287962A - Electrically conductive composite resin composition - Google Patents

Abstract

PURPOSE:To obtain a composite resin compsn. giving electrically conductive moldings which are homogeneous and stable, by blending a crimped metallic fiber with a resin. CONSTITUTION:An electrically conductive resin compsn. is obtd. by blending a crimped metallic fiber with a resin. The number of crimps is 3-200 pitches, pref. 10-100 pitches per 25mm of an apparent fiber length by its own weight. The magnitude of crimp (the crimp amplitude) is 0.05-4mm, pref. 0.1-2mm. Examples of the metallic fibers are those mainly composed of aluminum, iron, copper, cobalt, titanium or silver and also include amorphous metallic fibers. Examples of thermoplastic resins are polyolefin, polyamide, polystyrene and polyester. Examples of thermosetting resins are phenolic and epoxy resins. Examples of elastomers are polyurethane and silicone resin elastomers.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to electronic and electrical equipment, their parts including electric wires, and as a molding material for enclosures or mechanical parts of industrial and household equipment using them. The present invention relates to a suitable conductive composite resin composition.

(Prior Art) It has been conventionally practiced to impart conductivity by blending fibrous metal filler into black bean monomer or thermosetting resin. , a resin material for magnetic wave shielding is shown in which metal uAs is uniformly blended into a resin and molded.

(8 Problems to be Solved by the Invention) In the past, the conductivity of resin molded products containing conductive fillers was generally unstable and affected by environmental conditions, including not only fibrous metal but also powder and flake. It lacked durability against fluctuations. The conductivity within the molded product tends to be non-uniform, and it is extremely difficult to obtain high quality by molding, extrusion molding, or vacuum molding, which requires high molding pressure.

In order to improve these drawbacks, methods such as pre-treating the conductive filler with silane-based or titanium-based compounds, modifying the matrix polymer, and increasing the amount of conductive filler blended are being carried out. However, the improvement range is small, and adding a large amount of filler impairs the physical properties and moldability (flowability, etc.) of the composite resin, increasing the specific gravity, etc., which is the purpose of using conductive composite resins for weight reduction and cost reduction. The result is that it goes against the grain.

The present inventors have completed the present invention as a result of intensive research to improve the drawbacks of the prior art.

(Means for Solving the Problems) That is, the present invention uses a conductive composite resin composition made of a resin mixed with crimped gold FA fibers, which makes it easy to produce homogeneous and stable conductive molded products. can be obtained.

Hereinafter, the content of the present invention will be explained in detail according to its configuration.

The crimped metal fiber used in the present invention is obtained by crimping long metal fibers produced by a drawing method, a splitting method, a melt spinning method, etc. by a pressing method, a gear crimp method, etc. Including those cut into short fibers of n or less.

Metal long fibers include aluminum, iron, copper, nickel, fpartite, manganese, chromium, molybdenum 1 tungsten,
Main ingredients include titanium, silver, gold, baladium, platinum, rhodium, ruthenium, etc., and include so-called amorphous metal fibers. The cross-sectional shape of the fibers is circular, triangular, square,
The fiber diameter suitable for the effects, manipulations and creations of the 0 blend is 0.0.
The diameter is usually 1 to 100μ, but tape-shaped (or ribbon-shaped) long diameters of 0.1 to 811LN are also included.

The number of crimps is determined by the apparent fiber length of 250 cm due to its own weight only.
13 to 200 is appropriate, preferably 10 to 100
It is. The size of the crimp (the height of the crest) is usually 0.05 to 4.
fi is used, preferably 0.1 to 2 mm
It is.

The resin (matrix polymer) used in the present invention may be either thermoplastic or thermosetting, and is selected according to the usage of the composite resin.

Examples of thermoplastic resins include polyamide 1 polyurethane, polyester, polycarbonate, polyphenylene oxide, polyacetal, polyolefin, polydiene, polystyrene, polyacrylonitrile A B C resin, polyacrylate-polyvinyl alfur, polyvinyl acetate, polyvinyl chloride, Examples include polyvinylidene chloride-polyfluoroethylene, cellulose acetate, and various copolymers and mixtures thereof.

Examples of thermosetting resins include phenolic resin, unsaturated polyester AI resin, polyimide, epoxy resin, silicone resin, and the like.

Used in the present invention! Elastomers having rubber-like elasticity regardless of their cross-linked structure are also included as resins. Elastomers can be used alone or in combination with other resins.

Preferred resins include polyolefin, polyamide, polyester, polystyrene, thermoplastic resin containing polyacrylonitrile as a main component, polyolefin, polydiene, polyurethane, polyamide, polyester, polystyrene, silicone resin, and 1% elastomer.

In addition to the gold #4 fibers and the matrix polymer, an eighth substance can be added to the composition of the present invention if desired. For example, antioxidants, ultraviolet absorbers, lubricants, mold release agents, flame retardants,
Pigments, dyes, crystallization accelerators, plasticizers, glass fibers, carbon fibers, mica, talc-wollastonite, silica, spherical glass, spherical phenolic resins, etc. may be blended.

The amount of metal fiber blended varies depending on the intended use of the composition, but
Usually 0.1 to 90% of the total composition expressed as %
TL amount% range, preferably 0.3 to 8ON amount%
It is. In particular, for electromagnetic shielding, which is one of the main uses of the composition of the present invention, the content is 0.5 to 6 ONk%. O,1
If the amount is less than 5% by weight, sufficient conductivity cannot be obtained, and if the amount exceeds 901% by weight, blending, crosstalk, and molding operations tend to be difficult.

Methods for blending crimped metal fibers and resin include impregnating a metal fiber woven ring, nonwoven fabric, or fiber bundle (including single fiber bundles) with resin, and cutting metal fibers into short pieces. Examples include a method of kneading a material with a resin. There is also a method in which a fiber bundle is impregnated with a relatively small amount of resin in advance and cut into short pieces, or the short fiber bundle is mixed as it is with the main matrix polymer during molding.

It is often advantageous to surface-treat the metal fibers prior to compounding to control and improve their affinity and dispersibility with the resin. Examples of modifiers include silane-based, titanium-based, and tin-based coupling agents.◎ Matrix polymers also improve affinity with metal fibers and dispersibility, as well as improve moldability, physical properties, and Various additives can be added to improve the appearance.

(Effects of the invention) The conductive resin composition eyelids obtained by the present invention have superior conductivity compared to compositions of the same type with the same fiber diameter and the same blending amount, and are molded with stable and homogeneous physical properties. Goods can be obtained. Furthermore, the molding pressure dependence and temperature dependence of conductivity, etc. are small, and high quality products can be obtained not only by injection molding and compression molding, but also by relatively low pressure molding such as extrusion molding and vacuum forming.

As a result, the composition of the present invention can reduce the amount of metal fibers that are relatively expensive and have a large specific gravity, and is compatible with weight reduction and easy moldability.
This improves the cost and quality of molded products.In addition, the application of molded products can be easily expanded not only to the field of injection molding and 1'EE compression molding, but also to the fields of extrusion molded products and vacuum molded products.

The composition of the present invention can be used as a shielding material (or radiation and/or absorber) for unnecessary electromagnetic waves emitted by various electronic and electrical equipment, for enclosures (casings, housings),
There are coating materials, sealing materials, mechanical parts, etc. Further, the present invention will be explained in more detail with reference to Examples below, but the present invention is of course not limited thereto.

Examples 1 to 8, Comparative Examples 1 to 8 Although the diameters and the number of bundled fibers were different, the stainless steel long fibers, copper long fibers, and aluminum long fibers shown in Table 1 were each crimped into fibers using a gear crimper. The average number of crimps is 2 each.
2.18.20 pieces, crimp height was 0.5±0.1 tm. These were continuously immersed and coated with molten ethylene/methacrylic acid copolymer zinc salt, cooled and cut into chips having a length of about 8 fi. The weight percentage of metal fibers is shown in Table-I
These master chips were mixed with polyamide resin (nylon 6) chips and fed to an injection molding machine.
Test pieces for various physical properties were molded.

For comparison, metal fibers without crimping were made into master chips using ethylene/methacrylic acid copolymer zinc salt in the same manner as in y, and this was mixed with nylon 6 chips and molded.

The physical property evaluation results of the molded products of Examples and Comparative Examples are shown in Table 2, and it is clear that the specific resistance indicating conductivity and the heat cycle resistance thereof are excellent.

The heat cycle test is 85℃/1 hour, 25℃
The treatment was performed in one cycle of 1 hour at -30°C, 71 hours at 25°C, and was repeated 1°.

(Hereinafter, blank space) 1. Example 4, Comparative Example 4 Stainless steel fibers obtained in Example 1 and Comparative Example 1 +7)Y
The X-tertifier is mixed with flexible ethylene polymer and diene polymer polymer (so-called EPDM) chips and fed into a single-screw extruder, with an extrusion pressure of about 1゜kq/d and a diameter of 1
2 The same round bars were continuously extruded.

The resistivity and durability (heat cycle test) of the round bar obtained in Example 4 were significantly superior to that of Comparative Example 4. (Table 3) The heat cycle test was conducted at 55℃7
1 hour, 25℃/1 hour N-40℃/1 hour, 25℃7
One cycle was performed for one hour.

Table 8 Example 5 to Comparative Example 5 Stainless steel long fibers with a diameter of 8 μm and a bundle number of 10 were crimped into fibers using a gear crimper with different numbers of teeth and tooth heights, and molten styrene-butadiene block copolymer was added to the crimped fibers. Continuously dipped, set up, cooled and cut into lengths of approx.
It was made into a H chip. These master chips having a fiber weight percent of about 60 were mixed with polyethylene terephthalate and Hibisphenol A polycarbonate chips and fed into an injection molding machine to mold various physical property test pieces. The mixing ratio was metal fiber master chip/polyethylene terephthalate/polycarbonate=25/80/45 (weight ratio).

For comparison, fine stainless steel fibers that were not crimped were made into master chips in the same manner as above, and then molded.

Claims (7)

[Claims] (1) A conductive composite resin composition comprising a resin mixed with crimped metal fibers. (2) The composition according to claim 1, wherein the number of crimp of the metal fiber is 3 to 200 per 25 mm, and the crimp height is 0.05 to 4 mm. (3) The composition according to claim 1, wherein the metal fibers are mainly composed of aluminum, iron, and copper. (4) The composition according to claim 1, wherein the metal fibers are made of an amorphous metal. (5) The composition according to claim 1, wherein the metal fibers are crimped by a gear crimper. (6) The composition according to claim 1, wherein the resin is a thermoplastic resin whose main component is polyolefin, polyamide, polyester, polystyrene, or polyacrylonitrile. (7) The composition according to claim 1, wherein the resin is a polyolefin, polydiene, polyurethane, polyamide, polyester, polystyrene, or silicone resin-based elastomer.