Process for the preparation of poly-1,4-dihydro-2,6- dimethyl pyridino-3,5-dicarboxylic esters, thermally stabilized vinyl chloride polymer or copolymer based compositions containing them and process for stabilization of the said polymers or copolymers

摘要

This invention relates to a process for the preparation of poly-1,4-dihydro-2,6-dimethyl pyridino-3,5- dicarboxylic esters of general formula (I) IMAGE in which A, B, R, j, k and m have the meanings indicated in the claims, which comprises one of the following three variants of the Hantzsch synthesis: a) condensation of an aldehyde with an appropriate bis- acetoacetate and ammonia, with the removal of water, b) condensation of an aldehyde with a suitable bis-beta- aminocrotonate and the removal of water and ammonia, or c) condensation of an aldehyde with a bis-beta- aminocrotonate and a bis-acetoacetate and elimination of water, and recovering the product of general formula I in the form of a fine powder by evaporating the reaction solvent and drying the solid residue by drying in a fluidized bed drier. Compositions based on thermally stabilized vinyl chloride homopolymers or copolymers containing the said compounds of general formula I and a process for their preparation are also included within the scope of the invention.