High melt index polystyrene foam and method

摘要

A polystyrene resin in foam form having a basis weight of less than about 20 g/100 in2 and a density of about 6 lbs./ft3 or less, the foam precursor of which is either a polystyrene having a melt index of about 8 or more or a polystyrene in combination with a minor proportion of any other material which will result in a melt index of about 8 or more. A method of forming such a polystyrene resin foam structure includes combining the resin in molten form under pressure with the blowing agent of at least approximately 100% carbon dioxide and extruding the mixture through a die into an atmosphere of reduced pressure to form the foam structure.