JPS6151059A - Electrical conductive thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide the titled resin compsn. which is flame-retardant and does not cause lowering in electrical conductivity even under high temperature conditions, by incorporating an organotin compd. in a thermoplastic resin compsn. contg. a halogen flame retarder and an electrical conductivity-imparting agent. CONSTITUTION:An organotin compd. of formula I, II or III [wherein R is alkyl, aryl, alkylaryl; A is a sulfur or oxygen-contg. org. group (e.g., a group derived from a carboxylic acid or mercaptan derivative, phenoxy or alkoxy) other than hydrocarbon group] such as dibutyltin dilaurate or dimethyltin dodecylmercaptide is used. A thermoplastic resin (A) (e.g., polystyrene/butadiene resin), a halogen flame retarder (B) (e.g. tetrabromobisphenol A), an electrical conductivity- imparting agent (C) (e.g. metallic powder or fiber such as Cu, Ni or Al powder or fiber) and 0.5-5wt% (based on the amount of component B) said organotin compd. (D) are blended together.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a conductive thermoplastic resin composition that is flame retardant and has excellent conductivity.

[Technical background of the invention and its problems] With the spread of electronic type I in recent years, the problem of protecting electronic devices from electromagnetic interference has rapidly become a focus both in Japan and abroad. It's here. Therefore, electron 41
! Research is being actively conducted on various materials that can shield vessels from electromagnetic waves. Among a series of studies on electromagnetic shielding materials, one that has recently attracted particular attention is a highly conductive material with extremely low resistance that is made by kneading metal fillers such as metal fibers, metal flakes, and metal powder into thermoplastic resin for injection molding. Examples include polyurethane resin compositions. If this composition is used, it is simpler and easier to work with than other shielding methods, and a molded article having an extremely excellent shielding effect can be provided.

However, when a halogen-based flame retardant is contained in the conductive thermoplastic resin composition to impart flame retardancy, the halogen-based flame retardant is decomposed by heating during molding, and the halogen is released. The released halogen absorbs moisture and becomes a strong acid that corrodes the surface of the metal filler, or reacts with the metal to form a metal halide. As a result, the resistance of the resin molded body 171 increases and there is a flash point where conductivity is inhibited.

In particular, when treated at high temperatures, the conductivity decreases significantly and the desired shielding effect cannot be achieved.

[Objective of the Invention] The object of the present invention is to provide a conductive thermal conductive material with high shielding effect, which does not reduce its conductivity even when it contains a halogenated flame retardant, is stable even at product temperature, and has excellent conductivity. The present invention aims to provide a plastic resin composition.

[Summary of the Invention] In the present invention, as a result of extensive research to eliminate the above-mentioned drawbacks, it has been discovered that deterioration of GTr properties can be prevented by using an organic tin compound.

That is, the present invention provides a conductive thermoplastic resin characterized in that it contains (A) a thermoplastic resin, (B) a halogen flame retardant, (C) a conductivity imparting agent, and (D) an organotin compound as essential components. It is a composition.

The thermoplastic resin (A) used in the present invention includes polyethylene resin, polypropylene resin, polyvinyl chloride resin,
Examples include polystyrene-butadiene resin, acrylonidol-butadiene-styrene resin, polycarbonate resin, polyamide resin, polyacetal resin, polysulfone resin, polyphenylene sulfide resin, modified polyphenylene oxide resin, etc., and these may be used alone or in combination. Can be done.

Examples of the halogen flame retardant (B) used in the present invention include tetrabromobisphenol A1 perchloropentacyclodecane, chlorinated paraffin, and the like, which may be used alone or in combination of two or more. Halogen-based ff1l [flame agent is used as a flame retardant, but in order to enhance the additive effect, organic phosphorus compounds such as antimony trioxide, triphenyl phosphate, trialkyl phenyl phosphate, and dialkyl monophenyl phosphate are used in combination. can do.

As the (C)L9ffi property imparting agent used in the present invention,
Examples include metal powders of silver, copper, nickel, stainless steel, or gold PAm navy blue of aluminum, aluminum alloy, copper, nickel brass, bronze, vI iron, steel, stainless steel, etc.
These may be used alone or as a mixture of two or more.

The tin compound (D) used in the present invention has the following formula% (% formula%) (wherein R is an alkyl group, an allyl group, an alkyl-791
1st base, A represents a carbon IIQ a conductor, a mercaptan derivative, a phenoxy group, an alkoxy group other than a hydrocarbon group containing a sulfur atom or an oxygen atom, respectively.
This is shown in . Specific compounds include dibutyltin dilaurate, dibutyltin dibutylmaleny-1-, and bis(dinormalbutyltin monolaurate).
Maleny], dimethyltin dodecyl mercaptide, etc., and these may be used alone or in a mixture of two or more.

It is preferable that the blend m of the right lX1 tin compound contains 0.5 to 5% by weight based on the halogen flame retardant.

If the content of the blending matrix is less than O.Slz%, it will not be effective in stabilizing the conductivity, and if it exceeds 5% by weight, not only will the properties not improve any further, but the cost will increase, which is not preferable.

Generally, conductivity-imparting agents are oxidized by oxygen in the air, so treating the metal surface with an antioxidant such as a zero-inhibiting titanate compound or an amine compound is effective in developing conductivity. However, in a conductive thermoplastic resin composition containing a halogen-based flame retardant, when heated, it is difficult to develop conductivity, stable conductivity is not achieved, and the volume resistivity increases. Although the reason for this is not clear, it is presumed that the halogen compound, which is a flame retardant, is responsible. This is thought to be caused by (1) residual bacteria from the sulfuric acid catalyst during halogenation, (2) the presence of low-molecular-weight halides, and (3) halogen released by heat, and these are likely to cause damage to the metal surface of the conductivity imparting agent. It is presumed that this increases the contact resistance between metals.

The most important point of the present invention is that an organic tin compound is blended into a conductive thermoplastic resin composition containing a halogen flame retardant. It has been found that by blending this organotin compound, the volume resistivity does not change easily and is stable even during cross-wire processing and thermal stability tests of molded products.

The reason why the resistance is stable is that (i) the halogen decomposed and released by heating reacts with the organic tin compound, liberating the halogen.
Stabilize. (ii) It is presumed that the organotin compound is added to the halogen bond and stabilizes by preventing dehalogenation.

The conductive thermoplastic resin composition of the present invention is produced by blending multiple components and kneading them uniformly, and there is no particular restriction on the order of blending the components. After mixing the thermoplastic resin, the halogen-based fuel, and the conductivity imparting agent, the mixture is kneaded at 150 to 180°C to form a pellet, and an organic tin compound is added to the pellet to produce a composition. Furthermore, an organic tin compound may be mixed and kneaded at the same time as the 1-gene flame retardant is mixed.

The conductive thermoplastic resin composition of the present invention comprises a thermoplastic resin,
Although a halogen flame retardant, a conductivity imparting agent, and an organic tin compound are essential components, other lubricants, plasticizers, etc. can be added as necessary.

This composition can be formed into various shapes and forms depending on the application by vacuum forming, extrusion molding, injection molding, and calendar molding, and is particularly suitable for electronic equipment, communication equipment, medical equipment, etc. ■
It is useful as a material for instruments, measuring instruments, etc.

[Examples of the Invention] Examples of the present invention will be specifically described, but the present invention is not limited to these Examples.

Examples 1 to 4 Add 2 flame retardants to 100 parts of styrene-butadiene resin.
, 15 parts of 2-bis(4-hydroxyethyl-3,5-dibromophenyl)propane, 5 parts of antimony trioxide, and a diameter of 0.02 mm as a conductivity imparting agent.

Blend 10 parts of copper fibers with a length of 3 mm and mix with an extrusion kneader to
Kneaded at a temperature of 0 to 180℃, diameter 2mm, length 5m
I decided on a m beret. Next, dimethyltin dodecyl mercaptide was added as an organotin compound to the flame retardant.
A conductive thermoplastic resin composition was prepared by blending 1 to 5f4ffi% as shown in the table.

The obtained composition was injection molded into a flat plate using a screw in-line type injection molding machine at a mold temperature of 35 to 45°C, a cylinder tip temperature of 185°C, and an intermediate temperature of 190°C. The normal volume resistance of this flat plate.

Anti- and heat treatment L! ! (80℃ x 1ooo+-+ >
Shun's volume resistivity was measured according to JIS-6911. The results are shown in Table 1. At the same time, a conductive thermoplastic resin composition containing no organic tin compound was tested as Comparative Example 1, and the results are also shown in Table 1.

Table 1 Examples 5 to 7 100 parts of polypropylene resin, 15 parts of chlorinated paraffin as a refueling agent, 5 parts of antimony trioxide, and an average particle size of 8!5μ surface-treated with titanate as a conductivity imparting agent.
10 parts of carbonyl nickel powder, 10 parts of titanate-treated stainless steel fiber with a diameter of 30 μm and a length of 6+ nm, and 471% of the organotin compound bis(di-n-butyltin monolaurate) maleate 0.5 to 3 times.
were mixed and kneaded using an extrusion kneader at a temperature of 185° C. to produce pellets of a conductive resin composition with a diameter of 1.5 mm and a length of 3++ on. Using this pellet, a screw-in-line injection molding machine with a mold clamping pressure of 5 tons was used, the mold temperature was 45℃, the shilling-tip temperature was 180℃, and the intermediate temperature was 19℃.
A flat plate was made by injection molding at 0°C and a rear temperature of 160°C. About this flat plate, it is normal and Heat Nicle 1! (−
Conductivity was tested in accordance with J Is-6900 (repeating 10 cycles of 30°C x 30 minutes and 80°C x 30 minutes). □At the same time, a conductivity test was conducted using a sample containing no organic tin compound as Comparative Example 2. The results are also shown in Table 2.

As is clear from Table 2, Table 1, J3 and f82, the electrical conductivity of the Examples was stable without deterioration of various properties even after heating, confirming the remarkable effects of the present invention.

[Effects of the Invention] In a conductive thermoplastic resin composition containing a halogen-based flame retardant, by blending a gi tin compound, halogen Il! It prevents desorption of li and provides stable conductivity. In particular, it shows excellent conductivity without decreasing conductivity even after heating, and by using this conductive thermoplastic resin composition, it has a high shielding effect. Electronic equipment, communication equipment, and measurement equipment can be obtained.

Claims (1)

[Scope of Claims] 1 (A) thermoplastic resin, (B) halogen flame retardant, (
A conductive thermoplastic resin composition comprising C) a conductivity imparting agent and (D) an organotin compound as essential components. 2 Organotin compound is 0.5% compared to halogen flame retardant
The conductive thermoplastic resin composition according to claim 1, wherein the conductive thermoplastic resin composition contains 5% by weight.