JPH02208365A - Preparation of composite conductive polymer material molding - Google Patents

Abstract

PURPOSE:To prepare a conductive polymer material molding having improved properties to electromagnetic wave after a heat cycle test by compounding an insulating polymer material with a core material, tin or zinc, and a tin or lead salt of an org. acid, and extrusion molding the resulting compd. under deformation by a shearing stress. CONSTITUTION:A composite conductive polymer material molding comprising a compsn. wherein a conductive filler is dispersed in a matrix, i.e., an insulating polymer material, is prepd. by compounding the polymer material with a metal, inorg. or org. material of a spherical, particulate, flaky, whisker-like or fibrous shape, a core material, metallic tin or zinc, and a tin-lead salt, tin salt or lead salt of an org. acid and extrusion molding the resulting compd. at 150 deg.C or higher under deformation by a shearing stress into a desired product.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a composite conductive polymer material molded article.

[Prior Art] Currently, conductive polymer materials are used for various purposes depending on their electrical conductivity, and in particular those with a volume resistivity of 10-2 to 10
9 [Ωcm) material is used. Broadly speaking, it can be classified into two functions: conductive function and shielding function. For the former, only volume resistivity is important, and specific applications include cable conductive layers, heating resistors, paints, antistatic materials, electroplating materials, printed circuits, and electrode materials. The latter has a very close relationship with not only the volume resistivity but also the arrangement of the conductivity imparting substance such as the dispersion state within the conductive material and the wavelength of the transmitted electromagnetic waves.Specific applications include electromagnetic wave shielding materials and radio wave absorbers. There is something like that. In addition, charge transfer complexes, doped polymers, etc. have sensor functions, catalytic effects, photoelectric effects,
Some also have memory effects.

Among these conductive polymer materials, electromagnetic shielding materials using composite conductive polymer materials are used for IC, LSI, etc.
Housings for electronic devices that house a large amount of electronic devices used to be made of metal, but most of them have changed to plastic housings due to their compact size, light weight, and low cost. However, electromagnetic waves generated from inside the electronic device housing are transmitted and radiated to the outside of the device as unnecessary electromagnetic waves, and as a result, they affect other devices, such as noise and malfunction. On the other hand, as a countermeasure for shielding electromagnetic waves that are subject to electromagnetic influences from the outside, a method has been adopted in which unnecessary electromagnetic waves are shielded by imparting conductivity to plastic.

One of them is a method of molding with a composite conductive polymer material. This material is obtained by dispersing and compounding a conductive material in an insulating polymer material, and in the insulating polymer material, the conductive materials are in electrical contact with each other to form an electrical conduction path. . Therefore, the electromagnetic waves are repeatedly reflected and absorbed on the surface of the composite conductive polymer material and the conductive layer, and are attenuated and disappear.

As this electrically conductive material, materials that have electrical conductivity such as carbon powder and fibers, metal fibers, metal flakes, and metal-coated glass fibers are used.

In addition, thermoplastic resins such as polyethylene resins, polypropylene resins, ABS resins, and polystyrene resins are used as the insulating polymer material, and thermoplastic elastomers, rubber, thermosetting resins, etc. are also used.

This composite conductive polymer material does not require secondary processing to impart conductivity and has the advantage of good productivity.Also, since it requires high filling of conductive material, Physical properties tend to decrease and specific gravity tends to increase.

Therefore, there has been a demand to keep the filling rate of these conductive materials low.

However, if the filling rate of the conductive material is lowered, the number of electrical contacts between the conductive materials that form the basis of the conductive paths formed in the insulating polymer material decreases, resulting in a decrease in conductivity.
Alternatively, conductive materials that temporarily come into contact with each other to form a conductive path during molding separate from each other after a heat cycle test, resulting in a considerable reduction in electromagnetic wave shielding properties.

As one of the solutions to these problems, for example,
As disclosed in No. 20270 and Japanese Unexamined Patent Publication No. 63-218310, a method has been proposed in which a low melting point metal is blended to bond R-electronic materials to each other. It is true that with this method, even if the filling rate of the conductive material was lowered, the same electromagnetic wave shielding effect as before the lowering could be obtained, and the heat cycle resistance was also extremely good.

[Problems to be Solved by the Invention] However, the method disclosed in Japanese Patent Publication No. 63-20270 uses a conductive material in which an inorganic or organic core material is coated with a low melting point metal. Depending on the combination of and insulating polymer material, wettability may be poor and
There may be parts where the electrical materials do not bond to each other, and the electromagnetic wave shielding performance may be lower than when using low-melting point metals or uncoated conductive materials. Especially when using non-conductive materials for the core. At the time, wettability as described above was extremely important, and the types of insulating polymer materials that could be used were limited.

Furthermore, in the method disclosed in JP-A No. 63-218310, it is necessary to consider the wettability of the conductive fibers, the low-melting point metal, and the insulating polymer material, and depending on the combination, the wettability of the conductive fibers may This sometimes hinders mutual connection.

In addition, it is difficult to control the amount of low-melting point metal, and an excessive amount of low-melting point metal may remain in the molded product in a seabird shape, deteriorating the strength of the molded product, or remaining inside the extrusion or injection molding machine. There were problems such as post-processing being time-consuming.

Therefore, the wooden invention solves the above problems, and
An object of the present invention is to obtain a method for manufacturing a composite conductive polymer material molded article, which can be molded using a conductive material having poor wettability with a low melting point metal, or even a material having no conductivity at all, as a core material.

[Means for Solving the Problems] A method for producing a composite conductive polymer material molded article according to the invention includes a composite conductive material comprising a composition in which a conductive filler is dispersed in an insulating polymer material as a matrix. In the method for producing a molded body of a polymeric material, a spherical, granular, flaky, whisker-shaped, or fiber-shaped material made of a metal, an inorganic substance, or an organic substance is placed as a core in an insulating polymeric material (D) that is a matrix. Material (A), metallic tin or metallic zinc (B), and organic acid silver/lead salt or organic acid silver or organic acid lead salt (C) are blended, and this is subjected to shear stress deformation at a temperature of 150°C or higher. It is extrusion molded while adding.

[Function] In the present invention, the core material (A), metallic tin or metallic zinc (B), and organic acid silver/lead salt or organic acid silver or organic acid lead salt (C ) are impregnated, mixed or coated, and formed while applying shear stress deformation at a temperature of 150°C or higher, alloy metals such as tin-lead or zinc-lead or zinc-tin are formed on the surface of the core material. is precipitated,
The core materials having this alloy metal layer are electrically cross-coupled with each other to form a four-conductor net, and the formed conductive net has extremely good heat cycle resistance and can be molded as described above. This also solves the problems encountered in the process.

More specifically, by using ion exchange between an organic acid metal salt and a metal, an alloy metal is precipitated on the surface of the core material, the core material is made conductive, and the core materials are bonded to each other, thereby creating a net-like structure. Let it form. This is intended to reduce the filling amount of the conductive material and to improve the electromagnetic wave shielding properties after the heat cycle test.

Furthermore, the manufactured composite conductive polymer material molded article can control the amount of alloy metal precipitation through ion exchange, and
Since the alloy metal precipitates on the surface of the core material inside the molded body, there is no excess metal in the 7-trix, creating a seabird-like shape in the molded body, and no excess metal remains in the molding machine.

Core materials used in the present invention include copper, aluminum,
All spherical, granular, flake, whisker, or fiber-shaped materials made of metals such as nickel, iron, gold, silver, and stainless steel, inorganic substances such as metal oxides, metal nitrides, and glass, and organic substances such as organic fibers; This core material may be coated with metal tin or metal zinc in advance, or
Or, the core material and metal tin or metal zinc are mixed together without coating.
- May be blended into RIX's insulating polymer material. Furthermore, metals such as bismuth, indium, antimony, cadmium, and silver may coexist together with metal tin or metal zinc.

Coating methods include electroplating, vacuum deposition, melt plating, electroless plating, etc., and blending methods include kneading with a Banbury mixer, Nigoo, oven roll, etc., single screw, 21! III and others using an extruder.

Examples of insulating polymer materials used as a matrix include thermoplastic resins such as polyethylene resin, polystyrene resin, polypropylene resin, ABS (acrylonitrile butadiene styrene) resin, polybutylene terephthalate resin, and polycarbonate resin, phenolic resin, and epoxy resin. , thermosetting resins such as melamine resin, urea resin, unsaturated polyester resin, polyurethane rubber, rubber such as 5BR (styrene-butadiene rubber), NBR (tolyl-butadiene rubber), polyisobutylene rubber, or TPR, etc. Crosslinking may be carried out by irradiation with radiation such as UV rays or ultraviolet rays, or by peroxide or the like. In addition, lubricants, anti-aging agents, polymerization degree deterioration inhibitors,
Polymeric material additives such as UV absorbers, inorganic and organic fillers, colorants, etc. can also be added.

In the present invention, the blending amount of the core material (A) is within the range of 1 to 30% by weight for metal materials, and 10 to 70% by weight for other core materials, based on the total composition. desirable. If the blending amount is less than the above range, the conductivity will be low, and
If the amount exceeds the above range, the physical properties and other properties of the resulting material will deteriorate, which is not preferable.

The amount of metallic tin or metallic zinc (B) is 0 for the entire composition.
As the organic acid silver/lead salt or the organic acid silver or organic acid lead salt (C), rosin acid, naphthenic acid, etc. are used as the organic acid in the range of 0.05 to 5.0% by weight. In addition, organic acid silver/lead salt or organic acid lead salt may be used as is, but organic acid silver/lead salt or organic acid silver/lead salt may be dissolved in a solvent and organic acid silver/lead salt may be used. Alternatively, it may be used as an organic acid silver or organic acid lead salt solution, and the blending amount is 05 to 4% relative to the previous composition.
It is blended in a range of 50% by weight. Further, an organic acid salt such as hismuth, indium, antimony, cadmium, zinc, silver, etc. may coexist with the organic acid silver/lead salt or the organic acid silver or organic acid lead salt. A specific example of the solvent is squalene. The mixing ratio of organic acid silver/lead salt or organic acid lead salt and metallic tin or metallic zinc is tin.

Lead = 6.4 or tin Lead = 91 is desirable. When this organic acid silver/lead salt or organic acid lead salt is blended into the insulating polymer adhesive by the immersion method, the ratio of the organic acid silver/lead salt or organic acid lead salt to the solvent is preferably about 13. .

In addition to the dipping method, methods such as coating and mixing can be used.

This organic acid silver/lead salt, organic acid silver or organic acid lead salt, metallic tin or metallic zinc, and the insulating polymer material matrix blended with the organic acid are subjected to shear stress deformation at a temperature of 150°C or higher. A composite conductive polymer material molded body is obtained by molding with an injection molding machine extruder or the like.

[Example] Example: Two copper fibers with a diameter of 50 μm that were tin-plated with a thickness of about 5 μm.
00 wood, extruded with ABS resin (manufactured by Japan Synthetic Rubber Co., Ltd.), and melt-coated with ABS resin. Cool this and
It was cut into a length of 6 mm using a pelletizer to obtain a master pellet. The master pellet was immersed in a 25% by weight lead rosinate solution (solvent: squalene) for 30 minutes. After that, it was dried at 80℃ for 1 hour, and a virgin pellet of ABS resin was added to this master pellet.
The compound had a tin-plated copper fiber filling rate of 15 weight. Thereafter, this compound was molded using an injection molding machine.

The molded product was a plate-like product with a thickness of 2 mm and a size of 6 cm x 6 cm, and both ends were shaved to form terminals. The conduction resistance between these two terminals was measured, and the volume resistivity of the molded product was estimated. After conducting a 600 hour Biel cycle test at -40°C to 80°C, the volume resistivity was roughly estimated in the same manner. Also,
The electromagnetic shielding effect was measured using the atpan test method.

Example 2 A molded article was made in the same manner as in Example 1, except that a tin-plated glass fiber with a diameter of approximately 50 μm was used as the core material, and the volume resistivity of this molded article was determined in the same manner as in Example 1. and the electromagnetic wave shielding effect was measured.

Example 3 A core material of 65/35 brass short fibers having a length of 3 mm and metal tin powder were kneaded in A B S II resin (manufactured by Japan Synthetic Rubber Co., Ltd.) at a ratio of 191 using a twin-screw extruder. At this time, the filling rate of the additive was limited to 15% by weight. This composite pellet was placed in a lead rosinate solution (solvent: squalene) at a strain of 25%.
After being immersed in water for 30 minutes, it was dried at 80° C. for 1 hour. After that, it was molded using an injection molding machine.

The volume resistivity and electromagnetic wave shielding effect of the obtained molded article were measured in the same manner as in Example 1.

Example 4 ABS resin (manufactured by Japan Synthetic Rubber Co., Ltd.) was prepared by mixing core material copper powder with an average particle diameter of about 100 μm and metal tin powder in a ratio of 19=1.
Then, the mixture was kneaded using a twin-screw extruder. At this time, the filling rate of the additive was limited to 15% by weight. This composite pellet was immersed in a 25% by weight lead rosinate solution (solvent squalene) for 30 minutes, and then dried at 80° C. for 1 hour. After that, it was molded using an injection molding machine.

The volume resistivity and electromagnetic wave shielding effect of the obtained molded article were measured in the same manner as in Example 1.

Comparative Example 1 Using copper fibers with a diameter of about 50 μm whose core material was tin-plated with a thickness of about 5 μm, 200 of these tin-plated copper fibers were bundled,
Extruded with ABS resin (manufactured by Japan Synthetic Rubber Co., Ltd.), AB
S resin was melt coated. This was cooled and cut into 6 mm lengths using a pelletizer to obtain master pellets. A virgin pellet made of ABS resin was blended into this master pellet so that the filling rate of tin-plated copper fibers was 15 weight. Comparans 1 to 1 were thus prepared and molded using an injection molding machine.

The volume resistivity and electric wave shielding effect of the obtained molded article were measured in the same manner as in Example 1.

Table 1 shows the volume resistivity values and electromagnetic shielding effect values obtained in Examples 1, 2, 3, and 4 and Comparative Example 1.

(Hereinafter, blank space) [Effects of the Invention] As explained above, according to the method for producing a composite conductive polymer material molded article of the present invention, a particularly large effect is seen in the heat cycle resistance of electromagnetic waves. By using this manufacturing method, even inorganic materials such as
Much more effective.

In addition, this manufacturing method makes it possible to reduce the filling amount of the 4-electric material, and the resulting molded pair has the physical properties inherent to the insulating polymer material that is the matrix, and at the same time has a high electromagnetic shielding effect. vinegar.

Additionally, it has the effect of providing reliable characteristics even for inorganic and organic materials that do not have conductivity themselves.

Agent: Patent Attorney Tadashi Sato

Claims (1)

[Claims] In a method for producing a composite conductive polymer material molded article comprising a composition in which a conductive filler is dispersed in an insulating polymer material as a matrix, the insulating polymer material as a matrix ( D) metal inside;
A core material (A) is a spherical, granular, flake, whisker, or fiber-shaped material made of inorganic or organic matter.
, metallic tin or metallic zinc (B), and organic acid tin/lead salt or organic acid tin or organic acid lead salt (C), and while applying shear stress deformation to this at a temperature of 150 ° C. or higher, A method for producing a composite conductive polymer material molded article, the method comprising extrusion molding.