Making impact resistant polymers

Abstract

Abstract What is disclosed are a method for making a transparent impact-resistant polymer comprising a rubbery phase of grafted polybutadiene and a hard copolymer phase, which polymer is adaptable to use as a molding material, which method comprises: (1) in a first polymerization stage, dissolving a solid polybutadiene rubber in a monomer mixture comprising (a) methyl methacrylate, (b) styrene, and (c) at least one of methyl acrylate or ethyl acrylate to give a solution containing from 3 to 10 percent by weight of said rubber, and then polymerizing the solution using an initiator promoting graft copolymerization and in the presence ab initio of a chain transfer agent until an amount of said monomer mixture which is one to two times the weight of said polybutadiene rubber introduced is converted, said monomers (a), (b), and (c) being present in said monomer mixture in a ratio by weight of (73±5): (22±2); (5±3) such that the index of refraction of the hard polymer phase produced by the polymerization is equal to that of said polybutadiene, and said initiator being one forming tertiary-butoxy or phenyl free-radicals on decomposition; (2) in a second stage, further polymerizing to a monomer conversion between 25 and 40 percent while stirring to subject the resulting polymer to shear forces producing polymer particles having an average diameter between 0.2 micron and 1.5 microns; and (3) in a third stage, further polymerizing to a monomer conversion greater than 80 percent, and polymers made by such a method.

Inventors

• 👤 Karl A. Jung
• 👤 Manfred Munzer
• 👤 Heinz Vetter
• 👤 Winfried Wunderlich

Bibliographic Details