Hydroxybenzylmalonic acid derivatives and their use as stabilizers for plastics

Abstract From the Canadian patent

Esters and amides from 4-hydroxy-and 4-amino-polyalkylpiperidines and hydroxybenzylmalonic acids substituted at the central carbon atom with an organic residue preferably alkyl-, esteralkyl- or phosphonoalkyl-groups are excellent stabilisers for organic polymers especially, for polyolefins. They protect the polymers as well against, light degradation as against thermo-oxidative degradation. The compounds can be prepared by hydroxybenzylation of the corresponding derivatives of substituted malonic acids. Bis-malonic acid derivatives may be obtained from the monomalonics by reaction with formaldehyde.