NEW FOAMED PLASTICS AND PRODUCTION THEREOF

摘要

PURPOSE:To improve heat resistance and water absorption resistance by copolymerizing a monomer mixture contg. a specified atm. of a mixture of t-butyl (meth)acrylate with (meth)acrylonitrile and thermally foaming the resulting copolymer. CONSTITUTION:A monomer mixture comprising 20wt.% or higher mixture of t-butyl (meth)acrylate with (meth)acrylonitrile in a ratio of (2:3)-(3:2) and other copolymerizable monomers depending on needs is allowed to undergo bulk polymn. at 50-120 deg.C in the presence of a radical polymn. initiator to give a copolymer having a mol.wt. of 50,000-500,000 and contg. structural units of formula I (wherein R is H or CH3) and of formula II in a molar ratio of the former to the latter units of (3:2)-(2:3) in an amt. of the sum of both units of 20wt.% or higher. The copolymer is thermally foamed at 180-240 deg.C to give a foamed plastics having an expansion ratio of 5-40 and a density of 0.02-0.25g/cc.