Crosslinked foamed body and a process for its production

A process for producing a crosslinked foamed body, which comprises vulcanizing and foaming in two stages a crosslinking and foaming composition at a vulcanization temperature of 120.degree. to 140.degree. C. for a vulcanization time of 5 to 10 minutes in a first step, and at a vulcanization temperature of 125.degree. to 160.degree. C. in a second step, the second step vulcanization temperature being higher than the first step vulcanization temperature by at least 5.degree. C., for a second step vulcanization time of 5 to 20 minutes so that the expansion factor becomes 3 to 10 times, the crosslinking and foaming composition comprising

• (A) a chlorinated ethylene/.alpha.-olefin copolymer rubber having a chlorine content of 20 to 40% by weight and a Mooney viscosity of ›ML.sub.1+4 (121.degree. C.)! of 10 to 190,
• (B) a triazinethiol represented by the general formula (1) ##STR3## wherein R.sup.1 represents --NR.sup.2 R.sup.3, --OR.sup.2 or --SR.sup.2 in which each of R.sup.2 and R.sup.3 represents a hydrogen atom, an unsubstituted or substituted alkyl group or an unsubstituted or substituted aryl group,
• (C) an alkyl ammonium halide and
• (D) a hydrazide blowing agent.