Process of making articles of foamed polymethyl methacrylate

Abstract From the Canadian patent

Process Of Making Articles Of Foamed Polymethyl Methacrylate, The invention relates to a process of making articles of foamed polymethyl methacrylate (PMMA). In a first process stage a mixture comprising monomeric methyl methacrylate plasticizer, preferably liquid foaming agent and catalyst is polymerized by heating and/or irradiation to form a foaming agent-containing solid body. In the second process stage this body is foamed by heating to the softening temperature of the plastic material. Either of these stages may also be performed continuously. The final product is clear-transparent and has large closed cells, a smooth surface is, light- and weather-resistant, readily workable has …