摘要 |
PROBLEM TO BE SOLVED: To provide a composition for an O-ring which does not generate white foreign matter on the surface of an O-ring even under an environment of high concentration of plasma and high heat resistance, and can be used in a dry etching device.SOLUTION: A composition for an O-ring, used in a dry etching device, is obtained by mixing 100 pts.mass of a perfluoropolymer, 5 to 20 pts.mass of polytetrafluoroethylene powder, 1 to 10 pts.mass of silicon oxide, and a vulcanizing agent. The perfluoropolymer comprises a repeating unit derived from fluoroolefin and perfluoroalkyl vinyl ether, respectively, and does not comprise a repeating unit derived from vinylidene fluoride. The silicon oxide is silicon oxide powder having a hydrophobic group on the particle surface. The vulcanizing agent comprises organic peroxide and a polyvalent allyl compound. In the composition for an O-ring, 5 to 10 pts. mass of the polyvalent allyl compound is mixed with respect to 100 pts.mass of the perfluoropolymer. |