Alkali metal salts of cross-linked polymeric microgels as nucleating agents for polyethylene terephthalate moulding compositions

摘要

Nucleating agents for polyethylene terephthalate moulding compositions comprise alkali metal salts of carboxylic acid-containing polymeric microgel particles which are prepared by polymerising in aqueous emulsion a monomer mixture containing about 5 to 50 percent by weight of polymerisable carboxylic acid monomers, up to 10 percent of a multifunctional cross-linking monomer and one or more carboxyl-free relatively water-insoluble polymerisable vinyl monomers.