Patent ID: 7088555

Claim:
A ramp which has a surface hardness of 2.6 GPa or more, and which is obtained by molding a polyacetal resin, said polyacetal resin being selected from the group consisting of an oxymethylene homopolymer as obtained by the terminal stabilizing treatment of an oxymethylene homopolymer substantially comprising oxymethylene units, said oxymethylene homopolymer being produced by using as a raw material formic aldehyde monomer, or a cyclic oligomer; an oxymethylene copolymer as obtained by the terminal stabilizing treatment of an oxymethylene copolymer produced by using the above-mentioned raw material and a comonomer; an oxymethylene-oxyalcohol copolymer having a branched molecular chain structure; and an oxymethylene block copolymer comprising 50% by weight or more of polyoxymethylene (POM) blocks and 50% by weight or less of blocks of a polymer different from said POM.