JP2001160319A - Conductive molding material and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroconductive molding material that can yield high conductivity, improve mechanical strength of the plastic body, and impregnate electrolytes and the like, and its manufacturing method. SOLUTION: This material is composed of a filler of 50 to 1,000 weight parts with respect to a thermoplastic resin of 100 weight parts, and an electroconductive molding material with continuing empty walls is used as the filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive molding material and a method for producing the same.
The present invention relates to a porous conductive material having conductive voids and a thermoplastic resin and having continuous open walls, and a method for producing the same.

[0002]

2. Description of the Related Art In general, a conductive resin composition is produced by filling and dispersing a conductive filler in a resin binder, and is used for molding electronic parts and the like that require electromagnetic shielding properties and conductivity. As a conductive filler used in such a conductive resin composition, a metal filler, a carbon filler, and the like are known.

[0003] Metallic fillers can impart high conductivity, but have disadvantages such as high specific gravity, easy breakage during molding, and easy wear of metal parts such as screws during molding. are doing.

On the other hand, carbon-based fillers such as carbon black and graphite have the advantage that metal parts such as a screw part are less worn during molding. In recent years, carbon fillers are frequently used as conductive fillers in conductive resin compositions. Have been.

As a method for producing a conductive resin composition comprising a carbon-based filler, for example, a method in which carbon black and graphite are used in combination, a propylene-ethylene copolymer containing ethylene proposed in JP-A-51-17937 is proposed. And a method of producing a composition by mixing conductive carbon and a resin, a method of producing a composition by mixing a resin film-treated carbon black and a resin film-treated graphite with polyethylene proposed in JP-A-61-218648, JP-A-60-83
A production method using carbon black having a large lubrication amount proposed in Japanese Patent Publication No. 35-135, and a production method using carbon black having a large lubrication amount and special graphite proposed in Japanese Patent Application Laid-Open No. 1-111161 are known.

[0006]

However, in the above-mentioned manufacturing method using carbon black and graphite as the conductive material, a high conductivity can be obtained as compared with the case where graphite is used alone, but a conductive material that can withstand practical use is obtained. Since it is necessary to use a considerable amount of carbon black and graphite in order to obtain the property, when a molded body is manufactured by ordinary extrusion molding or the like,
Not only the mechanical strength is reduced, but also the moldability is deteriorated. In addition, since carbon black and the like are expensive and have a high specific gravity, there is a problem that the cost and weight of the molded product are increased.

Further, Japanese Patent Application Laid-Open No. 61-218648,
JP-A-51-17937, JP-A-60-8335
In the production method proposed in Japanese Patent Application Laid-Open No. H11-111161, when the carbon-based filler is small, the conductivity is poor, and in order to obtain a high conductivity of 1 Ω · cm or less, a large amount of carbon is required. It is necessary to use a system filler. However, when the amount of the carbon-based filler is increased, as a result, the mechanical strength is reduced, and furthermore, a problem that the cost and the weight are increased is caused. There were drawbacks.

In recent years, as for electrode materials which are used as conductive materials, development of an electrode material which can be impregnated with an electrolyte has been eagerly desired, but such a conductive material has not been proposed.

The present invention has been made in view of the above-mentioned problems, and has a high conductivity, can improve the mechanical strength of a molded body, and can be impregnated with an electrolyte or the like. And a method for producing the same.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, a conductive molding material comprising a conductive filler and a thermoplastic resin and having a specific structure has solved the above-mentioned problems. They have found that they can be solved, and have completed the present invention.

That is, the present invention provides a conductive molding material comprising 50 to 1000 parts by weight of a conductive filler with respect to 100 parts by weight of a thermoplastic resin and having a porous shape having continuous open walls, and its production. It is about the method.

Hereinafter, the present invention will be described in more detail.

As the conductive filler constituting the conductive molding material of the present invention, it is possible to use a metal filler, a conductive carbon-based filler or the like generally used as a conductive filler. Is, for example, Fe, Ni, Co, Au, Ag, Cu, Al, P
Examples thereof include metal powder, metal flakes, metal fibers, and metal whiskers such as zinc oxide and tin oxide made of one or more of b and Sn or an alloy thereof, but are not particularly limited thereto. Examples of the conductive carbon-based filler include carbon black, graphite, and carbon fiber. Further, examples of the conductive carbon black include acetylene black, conductive furnace black, superconductive furnace black, conductive channel black, furnace black or channel black heat-treated at a high temperature of about 1500 ° C., and specific examples of acetylene black. Examples include electrified acetylene black (manufactured by Denki Kagaku Co., Ltd.) and Shaunigan acetylene black (manufactured by Shaunigan Chemical Co., Ltd.). Specific examples of the conductive furnace black include Continex CF (manufactured by Continental Carbon Co., Ltd.). Vulcan C (manufactured by Cabot Corporation) and the like, as specific examples of Superconductive Furnace Black, are Continex SCF (Continental Carbon And Vulcan SC (manufactured by Cabot Corporation). Specific examples of the conductive channel black include Colux L (manufactured by Degussa Corporation). Ketjen Black EC, which is a kind of furnace black, is exemplified. , Ketjen Black SC-600JD
(Ketjen Black International Co., Ltd.). In the present invention, it is preferable to use a conductive carbon-based filler because there is no problem of abrasion of metal and the like, and the conductive molding material has excellent conductivity and is lightweight.

The thermoplastic resin constituting the conductive molding material according to the present invention acts as an organic binder for binding the conductive filler, and is not particularly limited as long as it belongs to the category of the thermoplastic resin. For example, ethylene resins such as high-density polyethylene, low-density polyethylene, and ethylene-α-olefin copolymer; propylene resins such as polypropylene and ethylene-propylene block copolymer; ethylene-vinyl acetate copolymer; ethylene-acryl Ethylene-acrylate copolymers such as methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer; ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer Ethylene-methacrylic acid such as copolymerized ethylene-butyl methacrylate copolymer. Polyolefin resins such as acrylate copolymer: polyvinyl acetate: polystyrene, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer ( AB
S), modified polyphenylene ether copolymer (PPO)
Polystyrene resins such as: polyethylene terephthalate (PET), polybutadiene terephthalate (PB)
T), polyester resins such as polyethylene naphthate (PEN), polyarylate, liquid crystal polymer (LCP): polyarylene sulfide resins such as polyphenylene sulfide (PPS), polyphenylene sulfide ketone (PPSK), polyphenylene sulfide sulfone (PPSS) : Nylon 6, Nylon 6,6, Nylon 4,6, Nylon 12, aromatic nylon, polyamide resin such as polyamide-imide: Petroleum resin: Succinimide resin: polyvinyl chloride, vinyl chloride-ethylene copolymer, chloride Vinyl chloride resins such as vinyl-vinyl acetate copolymers and polyvinyl chloride-polyurethane: polyacetals and mixtures thereof. Among them, the conductive molding material of the present invention can be produced more easily,
It is preferable to use a polyolefin-based resin because the production cost at that time can be suppressed at a low cost, and the polyolefin resin is stable in the electrolyte and can be reduced in weight.

[0015] The conductive molding material of the present invention is particularly conductive,
Thermoplastic resin 1 because of its excellent mechanical properties
It is preferable that the conductive filler be 50 to 1000 parts by weight with respect to 00 parts by weight.

The conductive molding material of the present invention has a porous shape having continuous void walls. Here, when there is no continuous void wall, the conductivity of the obtained molding material is extremely poor. The continuous hollow wall referred to in the present invention is one in which holes are continuously connected, and has a shape called an open cell. The porous shape having such continuous open walls can be formed by fusing the surfaces of granular materials such as pellets and powder.

In addition, the conductive material of the present invention has a porous shape having the continuous voids, so that the continuous voids can be impregnated with a conductive material such as an electrolyte. It can be used as a material having more excellent conductivity. And the continuous void ratio at this time is 20%
It is preferable that it is above. The upper limit of the continuous void ratio is not particularly limited as long as it can be used as a conductive material, but is preferably 80% or less in order to maintain a stable shape.

The continuous void ratio in the present invention means the continuous void ratio (%) =） the true density of the conductive molding material (having no continuous voids) −the apparent density of the conductive molding material (continuous voids) ) {True density of conductive molding material (having no continuous voids)} × 100.

The conductive molding material of the present invention may contain an antioxidant, a heat stabilizer,
Lubricants, flame retardants, pigments, plasticizers, crosslinking agents, UV absorbers,
Auxiliaries, additives, and the like used in general resin materials such as a reinforcing agent may be appropriately added as necessary.

The method for producing the conductive molding material of the present invention is not particularly limited as long as the method is capable of obtaining the conductive molding material of the present invention, and may be produced by any method. In addition, since the conductive molding material of the present invention can be particularly easily and efficiently produced with high production efficiency, it is preferable to produce the conductive molding material by a production method including at least the following steps A and B, for example.

Step A: A step of producing a composition powder by melt-kneading a conductive filler and a thermoplastic resin to form a composition and then mechanically pulverizing the composition.

Step B: a step of fusing the composition powders obtained in Step A to each other to produce a porous conductive molding material having continuous open walls.

Here, the step A is a step of obtaining a conductive filler-thermoplastic resin composition by melt-kneading a conductive filler and a thermoplastic resin, and then pulverizing the composition by mechanical pulverization to form a powder. It is. In general, a conductive filler obtained by melt-kneading a conductive filler and a thermoplastic resin-a thermoplastic composition has a very low conductivity because its surface is covered with the thermoplastic resin. It will be. Then, by pulverizing the composition by mechanical pulverization, a conductive powder is present on the surface thereof, and it is possible to obtain a composition powder having excellent conductivity.

In the step A of the present invention, when a conductive filler-thermoplastic resin composition is produced by melt-kneading a conductive filler and a thermoplastic resin, a method using a general melt-kneading apparatus may be used. For example, as a kneading device, a co-kneader, a Banbury mixer, a pressurized kneader,
Henschel mixer, roll forming machine, a conventionally known blender such as an extruder, a method using a kneader, and the like, the kneading device, when using a conductive carbon-based filler, in order to prevent deformation or breakage of the carbon-based filler It is preferable to use a material designed to have low shearing force during kneading and high stirring ability. The conditions for the melt kneading are not lower than the melting temperature of the thermoplastic resin used.

A method for producing the composition powder from the obtained conductive filler-thermoplastic resin composition includes mechanical pulverization. Examples of such mechanical pulverization include room temperature mechanical pulverization and freezing mechanical pulverization. The effect of the present invention can be exerted by using any of the methods. However, the effect of the present invention is extremely high when powder obtained by refrigeration mechanical pulverization is used. The term "powder" used herein refers to a powder having a particle shape within a range that can be used in a general powder molding machine, but usually refers to a powder having a size of 30 mesh or less.

Further, the composition powder of the above-mentioned step A can be manufactured in a lump using an apparatus such as a micropelleter.

The step B of the present invention is a step of fusing the composition powders obtained in the above step A together to produce a porous conductive molding material having continuous open walls.

As a method of fusing the powders of the composition in the step B, there are, for example, powder slush molding, compression molding, and roll molding under conditions that can maintain pores between the powders and have continuous voids. A method of fusing powders together by a molding method such as molding can be given. As the fusion condition at this time, it is preferable that the fusion is performed at a temperature slightly higher than the melting point of the thermoplastic resin (Tm + 20 to 50 ° C.) and under a condition that almost no pressure is applied (normal pressure to 5 MPa).

[0029]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.

In the examples, the evaluation method of the obtained samples will be described below.

-Evaluation of Volume Specific Resistance- Volume specific resistance is measured by the method specified by the Japan Rubber Association (SRIS).
2301).

Example 1 Linear low-density polyethylene (manufactured by Tosoh Corporation, trade name: Lumitac 22-1 (density = 0.900 g / cm ³ , M
FR = 2.0 g / 10 min)) 100 parts by weight and 300 parts by weight of carbon black (Ketjen Black International, trade name Ketjen Black EC).
Using a 8 inch test roll (manufactured by Kansai Roll) set at 40 ° C., the mixture was kneaded for 15 minutes while being turned over to form a sheet, and then pellets were formed using a sheet pelletizer.

The obtained pellets were mechanically pulverized using a pulverizer (trade name: Turbo Mill T-400, manufactured by Turbo Kogyo Co., Ltd.) to make powder. The resulting powder passed through a 32 mesh screen at 100% by weight.

The obtained powder was compression-molded under a pressure of 1 MPa for 3 minutes using a compression molding machine set at 140 ° C. to obtain 1 mm having continuous voids (50% continuous voids).
A sheet-like molded body having a thickness was prepared.

A test piece was prepared from the sheet-like molded body,
When the volume resistivity was measured, it was 0.2 Ω · cm.

When this sheet-like molded body was impregnated with diethyl carbonate containing lithium perchlorate as an electrolyte, 0.4 g per 1 g of the sheet could be impregnated.

COMPARATIVE EXAMPLE 1 The pellets obtained in Example 1 were not powdered, but were used at a pressure of 10 ° C. by using a compression molding machine set at 140 ° C.
It was compression molded under MPa for 3 minutes to prepare a 1 mm thick sheet-like molded body without voids. When the volume resistivity was measured using the test piece thus obtained,
It was 5000 Ω · cm. When the electrolyte used in Example 1 was impregnated to confirm the porosity, impregnation was impossible.

[0038]

According to the conductive molding material of the present invention, excellent mechanical strength and conductivity can be obtained even if a small amount of conductive filler is added. Further, since the conductive molding material has continuous voids, the electrolyte can be impregnated. It is also possible to increase conductivity, and its industrial value is extremely high.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 7/16 C08K 7/16 C08L 23/00 C08L 23/00 101/00 101/00 H01B 13/00 501 H01B 13/00 501P // B29K 23:00 B29K 23:00 105: 04 105: 04 105: 16 105: 16 507: 04 507: 04 F term (reference) 4F074 AA20 AC02 AE06 AG08 CA51 CC04Y DA02 DA13 DA47 4F213 AA03 AA08 AB13 AB18 AC01 WA04 WA22 WA52 WA92 WB01 WE02 WE16 WE30 WF01 WK01 WK03 4J002 BA011 BB031 BB051 BB061 BB071 BB121 BC031 BC051 BC061 BD05 DA061 BD081 BF021 BL011 CF101 CF111 CF111 CF1N1 CB1511 5G307 HA01 HB01 HC01

Claims (5)

[Claims] 1. A conductive molding material comprising 50 to 1000 parts by weight of a conductive filler with respect to 100 parts by weight of a thermoplastic resin and having a porous shape having continuous open walls. 2. The conductive molding material according to claim 1, having a continuous void ratio of 20% or more. 3. The method according to claim 1, wherein a conductive carbon filler is used as the conductive filler.
3. The conductive molding material according to claim 1. 4. The conductive molding material according to claim 1, wherein a polyolefin resin is used as the thermoplastic resin. 5. The method for producing a conductive molding material according to claim 1, wherein at least the following steps A and B are performed. Step A: a step of melt-kneading a conductive filler and a thermoplastic resin to form a composition and then mechanically pulverizing the composition to produce a composition powder. Step B: a step of fusing the composition powders obtained in Step A together to produce a porous conductive molding material having continuous open walls.