JPS6032852A - Carbon black for electrically-conductive foam - Google Patents

Abstract

PURPOSE:The titled product providing foam having improved electrical conductivity, high expansion magnification, and compression hardness, containing carbon powder having a specific pH, specific surface area, and iodine adsorption amount, obtained by heat-treating a mixture of a specified carbon source substance and carbon black. CONSTITUTION:A mixture of an organic high polymer substance (e.g., vinyl chloride resin, styrenic resin, etc.) and/or bituminous substance (e.g., tar, pitch, etc.), and carbon black (preferably acetylene black, by-product black) having bonded barbons in the molecule is heat-treated preferably at 1,000-1,600 deg.C in a nonoxidizing atmosphere, to give the desired carbon powder having >=9pH, 40-70m<2>/g specific surface area, and 50-80mg/g iodine adsorption amount. 100pts.wt. base material resin such as urethane resin, etc. is blended with preferably 5-100pts.wt. carbon powder and 1-10pts.wt. blowing agent, and molded and processed by an extrusion molding machine, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to carbon black for conductive foams (hereinafter referred to as black for foams), and more specifically, to obtain a foam with excellent conductivity, high expansion ratio, and high compression hardness. This product relates to a black for foams that can be used for foams.

Conventionally, acetylene black-poor by-product black has been used as black for foams, but when producing foams with higher conductivity, the viscosity of the rubber or resin composition increases and the foaming ratio decreases. It had the disadvantage that large foams could not be obtained.

The present invention provides a new black for foams that eliminates the drawbacks of conventional blacks for foams.

In other words, the black for foams of the present invention is an organic polymer substance and/or a source W substance (hereinafter referred to as
Heat-treated mixture of carbon source material 5) and carbon black, PL-19 or higher, specific surface Mt40-70 2/
11 and carbon powder (hereinafter referred to as pyrolytic carbon powder) with an iodine adsorption amount of 50 to 80'g.

Hereinafter, the content of the present invention will be explained in detail.

The foam black of the present invention is made of pyrolytic carbon powder and has different properties from conventional foam blacks.

In other words, the slurry density of K-1469 from J is 9 or more, and the specific surface area is expressed by the amount of nitrogen adsorbed by Canter Soso (Specific Surface Area Measuring Instrument manufactured by Canter Chrome). is 40-70 m
2/&, The adsorption month of 17'1ON iodine water bath liquid measured by the measuring method of carbon black iodine plate IT of J Engineering SK-6221 is 50-80In9/y and 'C1 PH compared to conventional foam black. It has physical properties such as large specific surface area and small iodine adsorption capacity. If the physical property values are outside the above range, the conductive performance and foaming effect of the foam will be low, so it is not a good idea. L, <no.

An example of a method for manufacturing this black for foams is that it can be obtained by heat-treating a mixture of a specific deoxidized substance and a blasting agent carbon black at an elevated temperature.

To explain in more detail, examples of carbon source materials include vinyl resin, acrylonitrile resin, styrene resin, polyethylene resin, ethylene-hinyl acetate copolymer resin, ethylene-detagene copolymer latex, and natural gono2. , tar, bitumen, asphalt, etc. Although any raw material carbon black may be used, it is preferable to use the acetylene black by-product black that has the ability to provide a certain degree of conductivity.

The ratio of the carbon source material and carbon black is blended so that the carbon generated by thermal decomposition of the carbon source material after heat treatment is contained in the pyrolyzed carbon powder from 1 to 60%.
The reason for doing this is that the conductive performance is not sufficient in the 1st military zone, Jinwei, and the coarse particle content becomes large when the 30th military zone is exceeded.

In addition, the heat treatment is performed at a temperature of 1000°C or higher, preferably 1000-1
For example, at a temperature of 600°C and in a non-oxidizing atmosphere, hydrogen,
It is necessary to carry out the process in an atmosphere such as argon or heliwam. This is because if the temperature during heat treatment is less than 101) 0°C, the effect of imparting electrical conductivity will not be sufficient, and if it exceeds 1600°C, depending on the type of raw material carbon black, it will easily become graphitized and the effect of imparting electrical conductivity will decrease. .

In the specific use of the foam black of the present invention, the resin same is made into a crystal phase and mixed with a foaming agent and a foaming aid in a mixer.

Regarding the blending ratio of black for foams, for example, urethane resin, ethylene-vinyl acetate copolymer, acrylic ester resin, acrylic ester-vinyl acetate copolymer, polybutadiene, polyethylene, vinylidene chloride resin, vinyl acetate resin, poly Acrylonitrile, epoxy resin, etc. are used as the base resin or base rubber, and the amount is preferably 5 to 100 parts per 100 parts by weight. If it is less than 5 parts by weight, the effect of imparting tetraelectricity will be small, and if it exceeds 100 parts by weight, the effect of imparting isoelectricity will be large, but the viscosity of the composition will increase and the foamability will deteriorate, which is not preferable.

Next, as blowing agents, ammonium carbonate, M carbonate soda,
Inorganic blowing agents such as sodium nitrite, nitrourea (NH2CONHN02), calcium carbonate, magnesium carbonate, etc., organic blowing agents such as nitron blowing agents, sulfohydrazide foaming agents, azo foaming agents, etc.1 . The blending ratio is: base resin: 1 base rubber:
It is preferably 1 to 10 parts by weight per 00 parts by weight. If it is less than 1 part by weight, the foaming effect will be small, and if it exceeds 10 parts by weight, the foaming effect will be large, but the compression hardness of the foam will be low, which is not preferable. Examples of foaming aids include urea-based aids, organic acid-based aids, metal salt-based aids, and the like. The blending ratio is preferably 0.1 to 5 parts per 100 parts of the base resin or base rubber. If it is less than 0.1 parts by weight, the foaming promoting effect is small, and if it exceeds 511 parts by weight, the foaming promoting effect becomes too large, which is not preferable because the compression hardness of the foam becomes low.

In producing black compound 1 for unexploded foam and foam, Ti1J raw materials are mixed and kneaded (-1
Extrusion Seijo machine, hydraulic press, Moldy 7
It can be molded into products such as sheets, sponges, or tuplars by using tools such as glue.

The foam manufactured in this way has a low volume resistivity and can be used for photographic equipment, printing machines, spinning machines, various types of equipment, sound equipment, CV: heat insulating materials, etc. Is possible.

Next, the present invention will be explained in more detail with reference to a black foam material example.

Examples 1 to 6 O': and Comparative Examples 1 to 6 Vinyl chloride resin (Kameki Kagaku Kosai Co., Ltd. jl! 8! Trade name [Denka Black J) 100 parts by weight OJ: 180 parts by weight The mixture was made using N2 gas stone, which was kept at a temperature of 1300'C, and then fired for 1 hour to form a pyrolytic carbon powder 1091 lid. The physical properties are shown in Table 1 together with acetylene black and 51U aluminum black.

Production of foam The pyrolytic carbon powder obtained by the above method was used as black for foam in the proportions shown in Table 2, and 100 parts by weight of polyurethane (manufactured by Nippon Polyurethane Industries Co., Ltd., part name (Coronate LJ)), Nitrosopentane methylenetetramine (manufactured by Shiraishi Calcium Co., Ltd. part name) as a blowing agent
DPTJ) 8 parts by weight and 1 mk part of urea powder (Mikata Toatsu Kagaku Co., Ltd. n) as a foaming aid were mixed in a mixing roll.
After cross-heating at 60℃ for 10 minutes, 100~11
A foam was obtained by heating in a 0°C steam bath for 20 minutes. Table 2 shows the measurement results of the expansion ratio, volume resistivity, surface resistance, and compressive hardness of samples obtained by slicing this foam into 10 x 30 x 500 pieces (thickness x m x length).

Examples 4 to 6 and Comparative Examples 7 to 12 Ethylene-vinyl acetate copolymer (manufactured by Nippon Unicar Co., Ltd., part name "Noc-31451J") 10 as the base resin
02It parts 1 P,E"-oxybisbenzenesulfonyl hydrazide 1♂ (manufactured by Hydraulic Chemical Co., Ltd., part name "Neocelbon p#1000J") 6 parts by weight as a blowing agent.

Stearic acid (reagent) υ as a foaming aid, 8 parts by weight.

Mixing roll temperature 140'C! The same 4y'J as in Examples 1 to 6 and Comparative Examples 1 to 6 was carried out except for 7 points. The results are shown in Table 6.

Tables 2 and 6 show that the foam containing the foam black of the present invention has significantly improved 1-volume resistivity and surface resistance while maintaining the foaming ratio and compression hardness at or above the conventional level. I understand that there is.

The physical properties were measured as follows.

(1) Foaming ratio: true specific gravity aB of resin rubber before foaming
(measured with a PIC meter) and the specific gravity dA of the foam after foaming (calculated using the volume gravimetric method).

B Foaming ratio=-- A (2) Volume resistivity...Resistance was measured using a multimeter (manufactured by Takeda Riken Co., Ltd.), and the volume resistivity was calculated using the following formula.

PU2Ry, -- However, Pt1 volume resistivity (Ω, CrrL) R2 side constant value (Ω) θ=J thickness my) W-width Cv > l-length am) (3) Surface resistance ...11J x 5 on the surface of the sample
Two 1'lj parts coated with Dotite (Fujikura Kasei Co., Ltd.) with a thickness of 0.1 to 0.5 mm were prepared at a spacing of 1(]u+ and measured in the same manner as the volume resistivity. It was measured at 12 locations (4 locations and 3 locations horizontally) and expressed as the average value. (c unit: Ω) (4) Compression hardness: Measured from JIEIK 676, Ic.

Note that the X marks in Table 2, Table 6, No.) Volume resistivity and surface resistance could not be measured due to poor fluidity.

Patent Applicant Kamekikaq Konigyo Co., Ltd.

Claims (1)

[Claims] An organic polymeric substance with carbon bonded in its molecules and a mixture of W and carbon black are heat-treated.
Above, specific surface area 40-70m"/& and iodine adsorption amount 50
~BOynr; Carbon black for conductive foam containing carbon powder of t/11.