JPS6042461A - Electrically conductive thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. having excellent mechanical strength and moldability, by blending graphite or a mixture thereof with carbon black with a mixutre of a thermoplastic resin and a specified thermoplastic elastomer. CONSTITUTION:A thermoplastic resin compsn. is obtd. by blending 15-200pts.wt. graphite or mixture thereof with carbon black with 100pts.wt. mixture obtd. by adding 1-80wt% satd. styrene thermoplastic elastomer (A) [e.g. a styrene/butylene(/olefin)/styrene block copolymer] or satd. olefin elastomer (A) (e.g. satd. elastomer of EPDM) to 20-99wt% thermoplastic resin (B) (e.g. PE or PP). When graphite or a mixture thereof with carbon black is added to the thermoplastic resin, impact strength and other mechanical strength are lowered and melt viscosity is increased so that the compsn. is difficultly moldable. The titled compsn. which is freed from such disadvantages can be obtd. by adding component A.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrically conductive thermoplastic resin composition, and more specifically, it is an object of the present invention to provide a thermoplastic resin composition that has excellent mechanical strength and high electrical conductivity. It is.

At present, materials made of plastics that have been made conductive are used in a wide range of applications, including antistatic molded products, surface heating elements, CV cables, conductive paints, and conductive inks. The most common method for imparting electrical conductivity is the addition of carbon black or graphite.

-1 Conductivity Regarding the degree of conductivity of plastics, since plastics are originally insulating materials, efforts are being made to obtain as high conductivity as possible, that is, a low resistance value. If we now talk about adding carbon black or graphite to increase conductivity, it is well known that conductivity can be increased by increasing the amount of carbon black or graphite added. Disadvantages of this include a decrease in impact strength and low mechanical strength, and an increase in melt viscosity, making molding difficult. Due to these drawbacks, 10° to 1
The reality is that there are almost no materials available that have high electrical conductivity such as 0-"Q-c, m, mechanical strength that can withstand practical use, and good formability.
If a plastic material with high conductivity of 0° to 10' Ω-cm can be realized by the very economical method of adding carbon black or graphite, which has been widely used in the past, its use would be as an electrode material for batteries. It can be used in a wide variety of applications, including calculator contacts, printed circuits, electromagnetic shielding materials, and resistor elements.

In view of the above, the present inventors have attempted to obtain a material that has excellent mechanical properties such as impact strength and is easy to mold by kneading graphite or a mixture of graphite and carbon black into plastic. As a result of our studies, we have arrived at the present invention.

That is, the conductive thermoplastic resin composition of the present invention is a thermoplastic resin of 20 to 99% by weight and at least 1 to 80% by weight of at least one of a saturated styrenic elastomer or a saturated olefinic nidistomer, for a total of 100% by weight. This is a thermoplastic resin composition containing 15 to 200 parts by weight of graphite or a mixture of graphite and carbon black.

In the present invention, thermoplastic resins include polyethylene, polypropylene, ethylene propylene copolymer, ethylene propylene diene terpolymer, ethylene vinyl acetate copolymer, polyvinyl chloride, polystyrene, polyacetal, polyamides, polyphenylene oxide, and polyphenylene. Sulfide, polybutylene terephthalate, polyethylene terephthalate, polycarbonate, polymethylpentene, ABS, As, etc. are included. Saturated styrene elastomers include styrene butylene (olefin) styrene block copolymers made by saturated SBS rubber with the double bonds of sibutadiene by hydrogenation, and saturated olefin thermoplastic elastomers include Includes saturated nidistomers of EPDM. As the graphite, both natural graphite and artificial graphite can be used. Carbon black includes various types of carbon black produced by a channel method, a furnace method, an acetylene method, and a thermal method.

Conventionally, the problems when trying to obtain conductive materials by adding carbon blank or graphite to thermoplastic resins are as mentioned above.As the amount of graphite or graphite and carbon black added increases, the mechanical strength increases. The two major points are that the melt viscosity decreases and the melt viscosity increases, making molding difficult. Axie's "Ketjenblack ECJ" has the problem of being expensive and dusty.More specifically, by increasing the amount of added graphite or graphite and carbon black (including "Ketjenblack ECJ" mentioned above), it is possible to improve conductivity. When trying to improve the resistance, the volume resistivity value is 102 to 1.
There seems to be one boundary area around 03Ω1m. In other words, the amount of graphite or graphite and carbon black required to reach this specific volume resistivity value varies depending on the type of graphite or carbon black, but regardless of which carbon black is used, the specific volume resistivity shown here can be achieved. Value 102~
Up to 103Ω1, the above-mentioned decrease in mechanical strength and increase in melt viscosity are not such a big obstacle, and it can be reached relatively easily. ``When trying to obtain Q-cm, in order to clearly reduce the mechanical strength and increase the melt viscosity, it is necessary to add graphite or graphite and carbon black to the thermoplastic resin to increase the volume resistivity. At present, it is extremely difficult to obtain a material that has a high conductivity of 10° to 10-201 and is practical.

Here, in the conductive material using a mixture of thermoplastic resin and graphite or graphite and carbon black, according to research by the present inventors, a predetermined amount of saturated styrene thermoplastic elastomer, olefin thermoplastic nystomer manufactured by Matasha Saturation Co., Ltd. By adding the following, we disclose a material with excellent practical properties, namely mechanical strength and melt processing properties.

Another feature of the present invention is that it provides an inexpensive surface conductive material. That is, according to the present invention, the carbon black used in combination does not use the expensive carbon black mentioned above, but instead uses widely used inexpensive furnace-type, channel-type, acetylene-type carbon blacks, etc. It is possible to provide a material with high conductivity of 10° to ICΩ-tm. More preferably, when these inexpensive carbon blacks are used, a material with a much lower viscosity can be obtained and melt processing can be easily performed.

It is also possible to add to the composition of the present invention process oils that are processing aids normally used for rubber, such as paraffinic, naphthenic, and aromatic oils.
b. Furthermore, it is also possible to add various additives such as antioxidants, lubricants, inorganic fillers, colorants, flame retardants, and others. Further, it is also possible to add carbon fibers such as PAN type and pitch type carbon fibers as necessary.

Examples will be described below.

Example 1 The formulation shown in Table 1 was granulated by biaxial kneading at a mouth vk of 30%, and the volume resistivity, Izod impact value, and fluidity were measured, and the results are shown in the same table. The practical limit of the Izot impact value (with a notch) is said to be 3 kg-cm/cm or more, and the effects of the present invention are clearly demonstrated here.

Continuing from page 1 [Phase] Int, CI,' Identification code Internal reference number 0 Inventor Ko Katayama - 1-2-2 Uchisaiwai-cho Co., Ltd., Chiyoda-ku, Tokyo Sumitomo Bakelite

Claims (1)

[Claims] 1) Add graphite or graphite and carbon black to a total of 100 parts by weight, which is 20 to 99 weight % of a thermoplastic resin and 1 to 80 weight % of at least one type of saturated styrenic thermoplastic nidistomer or saturated olefinic thermoplastic nidistomer. A conductive thermoplastic resin composition containing 15 to 200 parts by weight of the mixture.