Abstract: Light and heat stabilizers for synthetic resin compositions and synthetic resin compositions containing such stabilizers are provided, comprising(1) at least one hindered and heterocyclic amine having the formula: ##STR1## wherein: X is a bivalent linking radical forming with the ring structure ##STR2## a nitrogen-containing heterocyclic ring having from five to seven ring atoms, preferably piperidine;R.sub.1 and R.sub.2 are each selected from the group consisting of lower alkyl, preferably methyl, and R.sub.1 and R.sub.2 taken together as pentylene (CH.sub.2).sub.5 ;R.sub.3 and R.sub.4 are each selected from the group consisting of lower alkyl, and R.sub.3 and R.sub.4 taken together as one of butylene--(CH.sub.2).sub.4, pentylene--(CH.sub.2).sub.5, and CH.sub.2 --C(CH.sub.3).sub.2 --NH--C(CH.sub.3).sub.2 --CH.sub.2 --;n is 1 or 2; andwhen n is 1, Y is selected from the group consisting of hydrogen, O.degree.

Abstract: Alkylene bis-thioalkanoic acid amide stabilizers are provided, as well as synthetic resin compositions containing the same, having the general formula: ##STR1## wherein: R.sub.1 is alkyl having from one to about fifty carbon atoms,R.sub.2 is alkylene having from one to about three carbon atoms; andR.sub.3 is alkylene having from two to about twelve carbon atoms.