Fluorine rubber composition and bladder for tire production

摘要

A fluorine rubber composition that provides high tensile strength and high elongation after vulcanization mutually compatible and from which favorable mechanical characteristics are obtained even in a high-temperature environment; and a bladder for tire production, which is manufactured using the same are provided. The fluorine rubber composition includes a rubber component containing a fluorine rubber and carbon black, wherein the carbon black has a specific surface area by nitrogen adsorption (N2SA) of 25 m2/g or more and not more than 180 m2/g and a dibutyl phthalate (DBP) absorption amount of 60 mL/100 g or more and not more than 180 mL/100 g; and in a kneading step (A) of compounding the carbon black in the rubber component, an average shear rate of a rotor surface of a kneading machine is 100 (1/sec) or more, and a kneading maximum temperature Tm is 120° C. or higher and not higher than 200° C.

主权项

1. A fluorine rubber composition comprising a rubber component comprising:
a fluorine rubber; carbon black; and a vulcanization system compounding agent containing a co-crosslinking agent, wherein the carbon black has a specific surface area by nitrogen adsorption (N2SA) of 25 m2/g or more and not more than 180 m2/g and a dibutyl phthalate (DBP) absorption amount of 60 mL/100 g or more and not more than 180 mL/100 g; the fluorine rubber is at least one member selected among (A) a copolymer of tetrafluoroethylene/perfluoroalkyl vinyl ether, (B) a copolymer of tetrafluoroethylene/propylene, and (C) a copolymer made of (i) at least one monomer selected among tetrafluoroethylene, hexafluoropropene, pentafluoropropene, trifluoroethylene, chlorotrifluoroethylene, vinyl fluoride, perfluoroalkyl vinyl ether and propylene, and (ii) vinylidene fluoride; and in a kneading step of compounding the carbon black in the rubber component, an average shear rate of a rotor tip point of a kneading machine is 100 (1/sec) or more, and a kneading maximum temperature Tm is 120° C. or higher and not higher than 200° C., wherein the elongation at break at 25° C. of the fluorine rubber composition after vulcanization is 400% or more and not more than 800%, and wherein a compounding amount of the co-crosslinking agent is 0.1 to 2.5 parts by mass based on 100 parts by mass of the rubber component.