Heat stabilizer for halogen-containing polymers

A stabilized composition comprising:

• (A) a stabilizer composition comprising:
• i. 44.500% to 93.990% by weight of at least one dimethyltin compound of formula (CH3)2Sn(S(CH2)mCOOR1)2 wherein R1 is a linear, branched or cyclic C10-C20 alkyl group and m is 1 or 2, optionally containing unsaturations in the form of double or triple bonds;
• ii. 3.000% to 40.000% by weight of at least one mono-methyltin compound of formula CH3Sn(S(CH2)nCOOR2)3 wherein R2 is a linear, branched or cyclic C10-C20 alkyl group and n is 1 or 2, optionally containing unsaturations in the form of double or triple bonds;
• iii. 0.010% to 0.500% by weight of at least one tri-methyltin compound of formula (CH3)3Sn(S(CH2)pCOOR3) wherein R3 is a linear, branched or cyclic C10-C20 alkyl group and p is 1 or 2, optionally containing unsaturations in the form of double or triple bonds;
• and
• iv. 3.000% to 15.000% by weight of at least one thioester of formula HS(CH2)qCOOR4 wherein R4 is a linear, branched or cyclic C10-C20 alkyl group and q is 1 or 2, optionally containing unsaturations in the form of double or triple bonds;
• and
• (B) a halogen-containing polymer, the stabilizer composition being present in an amount from 0.01 to 10 parts by weight per 100 parts by weight of the halogen-containing polymer.

A process comprising compounding (A) a stabilizer composition comprising:

• i. 44.500% to 93.990% by weight of at least one dimethyltin compound of formula (CH3)2Sn(S(CH2)mCOOR1)2 wherein Ri is a linear, branched or cyclic C10-C20 alkyl group and m is 1 or 2, optionally containing unsaturations in the form of double or triple bonds;
• ii. 3.000% to 40.000% by weight of at least one mono-methyltin compound of formula CH3Sn(S(CH2)nCOOR2)3 wherein R2 is a linear, branched or cyclic C10-C20 alkyl group and n is 1 or 2, optionally containing unsaturations in the form of double or triple bonds;
• iii. 0.010% to 0.500% by weight of at least one tri-methyltin compound of formula (CH3)3Sn(S(CH2)pCOOR3) wherein R3 is a linear, branched or cyclic C10-C20 alkyl group and p is 1 or 2, optionally containing unsaturations in the form of double or triple bonds;
• and
• iv. 3.000% to 15.000% by weight of at least one thioester of formula HS(CH2)qCOOR4 wherein R4 is a linear, branched or cyclic C10-C20 alkyl group and q is 1 or 2, optionally containing unsaturations in the form of double or triple bonds;
• and
• (B) a halogen-containing polymer.