Stabilizer compositions are provided to enhance the resistance to deterioration on heating of a halogen-containing resin, comprising (A) a sulfide compound of four-valent tin having linked to a tin atom at least one sulfide group, and through carbon 1 or 2 alkoxycarbonylalkylene groups having from 1 to 8 carbon atoms in the alkoxy group and from 2 to 3 atoms in the alkylene group; and (B) a tin mercaptoalkylenecarboxylic acid ester having linked to a tin atom through sulfur 2 or 3 mercaptoalkylenecarboxylic acid alkyl ester groups having 1 or 2 carbon atoms in the mercaptoalkylene group and 4 to 18 carbon atoms in the alkyl ester group, and through carbon 1 or 2 alkoxycarbonylalkylene groups having from 1 to 8 carbon atoms in the alkoxy group and 2 or 3 carbon atoms in the alkylene group. The stabilizer composition contains at lesast 5% by weight of the sulfide compound (A). Halogen-containing resin compositions stabilized with the above stabilizer composition are also provided.
Processability, color, and mechanical properties upon heating of a rubber modified styrene polymer are improved by incorporating in the polymer a new sulfide compound of four-valent tin having linked to tin through carbon 1 or 2 alkoxycarbonylalkylene groups having 1 to 8 carbon atoms in the alkoxy group and 2 to 3 carbon atoms in the alkylene group.