Nissin Kogyo Co., Ltd.

Schlumberger Technology Corporation

Fukoku Co., Ltd.

Tsuyoshi Watanabe

Toru Noguchi

Hiroyuki Ueki

Takushi Matsushita

Akira Magario

Shigeki Inukai

Masaei Ito

Takashi Wanibuchi

Takumi Sagou

The piston seal member is formed of a crosslinked rubber composition, the rubber composition including 100 parts by weight of an ethylene-propylene rubber, 20 to 60 parts by weight of a first carbon black, 50 to 100 parts by weight of a second carbon black, and 5 to 20 parts by weight of carbon nanofiber having an average diameter of 0.5 to 500 nm, the total amount of the first carbon black and the second carbon black being 70 to 160 parts by weight. The first carbon black has an average particle diameter of 35 to 100 nm and a DBP absorption of 50 to 200 ml/100 g. The second carbon black has an average particle diameter that is greater than the average particle diameter of the first carbon black and ranges from 60 to 500 nm and a DBP absorption of 5 to 50 ml/100 g.

Piston seal member and disc brake using the piston seal member

A heat-resistant seal material includes 100 parts by weight of a ternary fluoroelastomer, 1 to 30 parts by weight of vapor-grown carbon fibers having an average diameter of more than 30 nm and 200 nm or less, and carbon black having an average particle diameter of 25 to 500 nm. The heat-resistant seal material contains the vapor-grown carbon fibers and the carbon black in an amount of 20 to 40 parts by weight in total. The heat-resistant seal material has a compression set when subjected to a compression set test at a compression rate of 25% and a temperature of 200&#xb0; C. for 70 hours of 0 to 15% and a dynamic modulus of elasticity at 200&#xb0; C. (E'/200&#xb0; C.) of 30 to 100 MPa.

Heat-resistant seal material, endless seal member using heat-resistant seal material, and downhole apparatus including endless seal member

Growing community of inventors

Ina-machi, Japan

Tsuyoshi Watanabe