Alkyl-bridged tin-based thermal stabilizers for halogenated resins and synthesis and uses thereof
The present invention relates to stabilizer composition for halogen-containing polymer. It has recently been found that tin-based thermal stabilizers with a bridging alkyl group between two tin centers are effective stabilizers while having effectively double the molecular weight of the corresponding non-alkyl bridged stabilizer. It is expected that ongoing experimentation will confirm that the alkyl bridged stabilizers have much lower volatility which leads to greater retention of the stabilizer in the finished article.
1. A stabilizer composition for halogen-containing polymers, the stabilizer composition comprising at least two tin-based centers, and at least one bridging alkyl group between the at least two tin-based centers wherein the bridging alkyl group is tin-bound and where the bridging alkyl group is not active in the stabilization process and is effective in increasing the molecular weight of the stabilizer composition, wherein the stabilizer composition is of a type L 2 Sn—(X)(Y)—SnL 2 , wherein L is a ligand chosen from the group consisting of esters of thioglycolic acid, 2-ME esters of C12-C18 fatty acids, carboxylates, maleates, sulfides, 2-ME, mercaptans, and a blend thereof, and
wherein X and Y are tin-terminated, alkyl bridging groups.
2. The stabilizer composition of claim 1 wherein X and Y are linear or branched, saturated or unsaturated, with or without heteroatoms, with or without heterocycles, where the alkyl-based bridging group is C1 to C80.
3. A composition of PVC, CPVC or a blend thereof, the composition comprising a stabilizer, the stabilizer comprising:
at least two tin-based centers; and,
at least one bridging alkyl group between the at least two tin-based centers wherein the bridging alkyl group is tin-bound, and,
wherein the bridging alkyl group is not active in the stabilization process and is effective in increasing the molecular weight of the stabilizer composition
wherein the stabilizer is of a type L 2 Sn—(X)(Y)—SnL 2 ,
wherein L is chosen from the group consisting of an ester of thioglycolic acid, a 2-ME ester of C12-C18 fatty acids, a carboxylate, a maleate, a sulfide, 2-ME, a mercaptan, and any combination of two or more of an ester of thioglycolic acid, a 2-ME ester of C12-C18 fatty acids, a carboxylate, a maleate, a sulfide, 2-ME, and a mercaptan, and
wherein X and Y are tin terminated alkyl bridging groups.
4. The composition of claim 3 wherein X and Y are linear or branched, saturated or unsaturated, with or without heteroatoms, with or without heterocycles, where the alkyl-based bridging group is C1 to C80.