Processing aids for vinyl foam

Abstract

VINYL FOAM MARKETS Foamed PVC has been commercially available for at least 20 years, but is now becoming increasingly important because of recent improvements in technology and a broadening of applications. It has becomes one of the fastest growing markets in the vinyl industry, sparking enthusiasm among processors over new opportunities for vinyl foam, particularly in many wood-replacement applications. There are currently three major existing markets for PVC foam: (1) sheet, where the major application is signage, (2) profile, which is mainly used for trim and molding, and (3) foam core pipe for drain, waste and vent applications. These markets have grown worldwide at an annual rate of greater than 12% over the last three years. The benefits that vinyl foam offers include: low cost per unit volume, high rigidity, improved thermal insulation, high water resistance, and most importantly, the ease and versitility of being able to work with it. Rigid vinyl foam is, in many ways, just like wood. Impressive growth rates are forecast for vinyl foam, particularly in wood replacement applications in the building and construction industries, where its water resistance and high stiffness per unit weight are important attributes. Most commercial processing aids have a composition consisting of high molecular weight copolymers of methyl methacrylate and alkyl acrylates, where MMA is the major component. The glass transition temperature of these copolymers is generally greater than that of PVc.