JPH0329816B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a carbon black (hereinafter referred to as "highly conductive black") suitable for imparting conductivity to a synthetic resin and/or a rubber-like substance, and a conductive material containing a highly conductive black in a synthetic resin and/or a rubber-like substance. The present invention relates to sexual compositions. It has been known to add carbon black, such as acetylene black, special conductive furnace black, and by-product carbon black during synthesis gas production, to impart electrical conductivity to synthetic resins and/or rubber-like substances. . Table 1 shows the physical properties of specific examples.

【table】

[Table] Since these carbon blacks have a high specific surface area and a high iodine adsorption amount, when added to a synthetic resin and/or a rubbery substance, a composition with good electrical conductivity can be obtained.
However, when this is added, there is a drawback that fluidity and mechanical properties are reduced. The present invention aims to provide a highly conductive carbon black that solves the conventional drawbacks and a conductive composition containing the same. The first invention of the present invention is a product having a pH of 9 or more and a specific surface area obtained by thermally decomposing a mixture of a polymer and/or bituminous material that essentially becomes carbon at a temperature of 1000°C or more and a raw material carbon black.
40 to 70 m ² /g and an iodine adsorption amount of 50 to 80 mg/g, and the second invention is a highly conductive carbon black of the first invention and a synthetic resin and/or a rubber-like substance. This is a conductive composition containing 50 to 100 parts by weight and 100 parts by weight, respectively. The present invention will be further explained in detail below. The first invention of the present invention is a highly conductive carbon black obtained by thermally decomposing a mixture of a specific polymer and/or bituminous material and carbon black at a temperature of 1000°C or higher, and this is a highly conductive carbon black obtained by thermally decomposing a mixture of a specific polymer and/or bituminous material and carbon black at a temperature of 1000°C or higher. It is obtained by heat-treating a mixture of a polymer and/or a bituminous material (hereinafter referred to as a carbon source material) which essentially becomes carbon at a temperature of .degree. C. or higher and raw material carbon black at a high temperature. To further explain the manufacturing method, first, specific examples of carbon source materials include vinyl chloride resin, acrylonitrile resin, styrene resin, polyethylene resin, ethylene-vinyl acetate copolymer resin, styrene-butadiene copolymer latex,
Examples include natural rubber, tar, pitch, asphalt, etc. Further, although any raw material carbon black may be used, it is preferable to use the acetylene black or by-product black described above, which has the ability to impart a certain degree of conductivity. The ratio of the carbon source material to the raw material carbon black is such that after heat treatment, the carbon produced by thermal decomposition of the carbon source material is contained in the high thermal conductivity carbon black in an amount of 1 to 30% by weight. The reason is that if it is less than 1% by weight, the conductive performance is insufficient, and if it exceeds 30% by weight, the coarse particle content will increase. These raw materials are used after being granulated using a suitable granulator using water or a solvent as a medium. The heat treatment of this granulated material is preferably at 1000°C or higher.
It is necessary to carry out the process at a temperature of 1000 to 1600°C under a non-oxidizing atmosphere such as nitrogen, hydrogen, argon, helium, etc. If the heat treatment temperature is less than 1000°C, the effect of improving conductivity imparting performance will not be sufficient, and if it exceeds 1600°C, it will tend to graphitize, depending on the type of raw material carbon black, and the conductivity imparting performance will deteriorate. The carbon black thus obtained has a pH of at least 9, a specific surface area of 40 to 70 m ² /g, and an iodine adsorption amount.
It is 50 to 80 mg/g, and when blended with a synthetic resin and/or rubber-like substance, a conductive composition having desired physical properties can be obtained. If the pH value is less than 9, the specific area is less than 40/g, and the iodine adsorption amount is less than 50 mg/g, the conductivity imparting ability is small, and the specific surface area is 70 m ² /g, and the iodine adsorption amount is 80 mg/g.
If it exceeds mg/g, the ability to impart electrical conductivity increases, but this is not preferable because fluidity deteriorates when it is added to a synthetic resin and/or rubber-like substance to form a composition. Next, the second occurrence will be explained. The second invention is a conductive composition in which the highly conductive carbon black of the first invention is blended with a synthetic resin and/or a rubber-like substance. Specific examples of synthetic resins and/or rubber-like substances (hereinafter referred to as base polymers) with which highly conductive carbon black is blended include (1) polyethylene resins, ethylene-vinyl acetate copolymer resins, polypropylene resins, styrene resins, vinyl chloride resins; , vinyl acetate resin, methacrylic resin, acrylonitrile-butadiene-styrene copolymer resin, polyphenylene oxide (PPO resin), modified PPO resin,
Thermoplastic resins such as polycarbonate resin, polyacetal resin, polyamide resin, (2) phenolic resin, melamine resin, urea resin, alkyd resin,
Thermosetting resins such as epoxy resins and unsaturated polyester resins, (3) natural rubber, chloroprene rubber, isoprene-isobutylene copolymer rubber, styrene-butadiene copolymer rubber, butadiene-acrylonitrile copolymer rubber, ethylene-propylene copolymer Examples include rubber-like substances such as rubber, ethylene-butadiene block copolymer rubber, and urethane rubber.
In the present invention, the base polymer and highly conductive carbon black are contained in a proportion of 100 parts by weight and 5 to 100 parts by weight, respectively. If the highly conductive carbon black is less than 5 parts by weight, the conductivity of the composition cannot be sufficiently increased, and if it exceeds 100 parts by weight, the fluidity will deteriorate, which is not preferable. To prepare the composition of the present invention, a base polymer and a highly conductive carbon black are added, as well as known plasticizers, fillers, reinforcing agents, antioxidants, heat stabilizers, lubricants, flame retardants, crosslinkers, and crosslinkers. Various additives such as auxiliary agents and ultraviolet absorbers are blended as necessary, and this is mixed into dice-type mixers, V-type mixers, Henschel mixers, Banbury mixers, kneaders, and continuous kneaders with built-in rotors. The mixture may be mixed using a device such as the above. In addition, when processing the composition of the present invention to form a molded product, it can be used as it is or once melted and gelled to form a pellet, and then directly processed using an extruder, injection molding machine, press molding machine, roll molding machine, etc. It can be processed by a processing machine such as a rotary molding machine. The composition of the present invention can be expected to be used in sheets for preventing static electricity, earth belts for removing static electricity, communication antennas, planar heating elements, casings for shielding electromagnetic waves, coaxial cables, and films. Next, a detailed explanation will be given in Examples. Example 1, Comparative Examples 1 to 3 and 12 to 14 Manufacture of carbon black 30 parts by weight of vinyl chloride resin (trade name: Denka Vinyl SS-110S, manufactured by Denki Kagaku Kogyo Co., Ltd.), acetylene black (Denki Kagaku Kogyo Co., Ltd.) 100 parts by weight (trade name: "Acetylene Black Powder") and 180 parts by weight of water were granulated using a mixing granulator and dried. This was fed into a _N2 gas atmosphere furnace maintained at a temperature of 1300°C and fired for 1 hour to obtain 109 parts by weight of carbon black. Its physical properties are shown in Table 2. Production of conductive composition 30 parts by weight of highly conductive carbon black obtained by the above method and 100 parts by weight of ethylene-vinyl acetate copolymer resin (Nippon Unicar Co., Ltd. trade name "NUC-3145") were mixed in an internal volume. Put it in 60ml of Toyo Seiki Seisakusho product name "Rapoplastograph R-60" and set the blade rotation speed.
The mixture was kneaded for 10 minutes at 60 rpm and a temperature of 120°C. For comparison, the same procedure as in Example 1 was carried out except that the added black was replaced with the carbon black shown in Table 1. Measured values of these physical properties are shown in Table 2. Example 2 In the production of carbon black of Example 1,
Instead of vinyl chloride resin, use polyvinyl acetate emulsion (product name: Gisuke Konishi Co., Ltd. “CH-”)
1000'') was carried out in the same manner except that 30 parts by weight was used.105
Parts by weight of carbon black were obtained. Next, a conductive composition was produced in the same manner as in Example 1 except that this carbon black was used. These physical properties are shown in Table 2.

[Table] Example 3, Comparative Examples 4 to 6 and 15 to 17 In Example 1, polypropylene resin (Mitsui Toatsu Co., Ltd.) was used instead of the ethylene/vinyl acetate copolymer resin.
The same procedure was carried out except that 100 parts by weight (trade name: "BJHH-G") was used. For comparison, the same procedure was carried out except that the carbon black shown in Table 1 was used in the proportion shown in Table 3. These physical properties are shown in Table 3.

[Table] Example 4, Comparative Examples 7 to 9 The carbon black obtained in Example 1 and the styrene resin were mixed in the proportions shown in Table 4, and 2,6-dibutyl-4 methylphenol (BHT) was added as an antioxidant. ), 0.5 parts by weight of trinonyl phenyl phosphite (TNP), and 1.0 parts by weight of zinc stearate as a lubricant were added and kneaded. Its physical properties are shown in Table 4. In Table 4, styrene resins A and B are manufactured by Denki Kagaku Kogyo Co., Ltd. A is a highly fluid impact-resistant styrene resin with the trade name "HIS-3" and B is a styrene-butadiene block polymer with the trade name "STR-".
1602”. For comparison, the same procedure was carried out except that among the compounds shown in Table 1, commercially available carbon black was used in the formulation shown in Table 4.

[Table] Example 5, Comparative Examples 10 to 11 Table 5 shows the results of measuring the physical properties of a composition prepared by adding and kneading the carbon black obtained in Example 1 to chloroprene rubber in the proportions shown in Table 5. For comparison, Denka Black and Ketsutien EC shown in Table 1 were added and kneaded at the mixing ratios shown in Table 5.

【table】

[Table] The following materials were used as shown in Table 5. (1) Chloroprene rubber...Product name: Denka Chloroprene Rubber M-40, manufactured by Denki Kagaku Kogyo Co., Ltd. (2) Noxeller CZ: Anti-aging agent, manufactured by Ouchi Shinko Co., Ltd. Product name: Noxeler CZ-(3) Suncellar: Sanshin Vulcanization accelerator manufactured by Kagaku Co., Ltd., trade name "Suncellar 22" The physical properties of the carbon black used in the examples and comparative examples of the present invention and the physical properties of compositions using these were measured by the following method. A Physical properties of carbon black (1) PH...JISK1469 (2) Specific surface area...BET method (3) Iodine adsorption amount...JISK6221 B Physical properties of the composition (1) Volume resistivity...Injection molding of the obtained pellets 2mm thick x 70mm long x 20mm wide using a machine (Japan Steel Works, Ltd. J-15-75 type screw type automatic injection molding machine)
A flat plate of mm was prepared and used as a specimen. The measuring device is a digital multimeter (Takeda Riken Co., Ltd. product name "TR").
−6856”) was used. (2) Melt flow index...JISK-7210 Measured at temperature 200℃ and load 5Kg (3) Rockwell hardness...JISK-7202 (4) Izot impact value...JISK7110 (5) Vikatsu softening point...JISK-7206 (6) Breaking strength, elongation...JISK-7113 (7) Electrical resistivity...Japan Rubber Association standard
SRIS2301−1968 (8) Mooney viscosity...JISK6300 (9) Tensile strength, elongation, hardness, compression set,
All rebound modulus complied with JISK6301.

Claims (1)

[Scope of Claims] 1. A carbon black obtained by heat treating a mixture of a polymer and/or a bituminous material that essentially becomes carbon at a temperature of 1000°C or higher, and has a pH of 9 or higher and a specific surface area. is 40~70m2/ ^g
Carbon black with excellent conductivity characterized by an iodine adsorption amount of 50 to 80 mg/g. 2 A mixture of carbon black and a polymer and/or bituminous material that essentially becomes carbon at a temperature of 1000°C or higher is heat-treated, and the pH is 9 or higher and the specific surface area is 40.
~70m ² /g, and a conductive composition containing carbon black having an iodine adsorption amount of 50 to 80mg/g, and a synthetic resin and/or a rubber-like substance in a ratio of 5 to 1000 parts by weight and 100 parts by weight, respectively. thing.