Curable composition of halogen-containing polymer

A curable composition of a halogen-containing polymer composed of

• (1) 100 parts by weight of a halogen-containing polymer selected from the group consisting of chlorinated polyethylene, a chlorinated ethylene/propylene copolymer, a chlorinated ethylene/propylene/non-conjugated diene terpolymer, chlorosulfonated polyethylene, polyvinyl chloride, chlorine-containing acrylic rubbers, chlorinated butyl rubber, brominated butyl rubber, fluorine rubber, polychloroprene, polyepichlorohydrin, an epichlorohydrin/allyl glycidyl ether copolymer, an epichlorohydrin/ethylene oxide copolymer, and an epichlorohydrin/ethylene oxide/allyl glycidyl ether terpolymer,
• (2) as a crosslinking agent, about 0.1 to about 10 parts by weight of a 2,3-dimercapto-pyrazine or -quinoxaline compound having the following formula ##STR19## wherein R.sub.1 and R.sub.2 are identical or different and represent a hydrogen atom or a C.sub.1 -C.sub.8 alkyl group, or R.sub.1 and R.sub.2 are bonded together to form a benzene ring which may be substituted by at least one substituent selected from the class consisting of halogen atoms, a nitro group, a carboxyl group, lower alkyl groups and lower alkoxy groups;
• and R.sub.3 and R.sub.4 are identical or different and represent a member selected from the class consisting of a hydrogen atom, ##STR20## or R.sub.3 and R.sub.4 are bonded together to form >C.dbd.O, in which R.sub.5 and R.sub.6 are identical or different and represent a hydrogen atom or a C.sub.1 -C.sub.12 group selected from the class consisting of alkyl groups and cycloalkyl groups and R.sub.7 represents a C.sub.1 -C.sub.18 group selected from the class consisting of alkyl groups and aryl groups or R.sub.7 represents ##STR21## wherein R.sub.8 represents a C.sub.1 -C.sub.8 group alkylene group, and (3) as an acid acceptor, about 0.5 to about 50 parts by weight of a compound of a metal of Group II or IVa of the periodic table.