Composition comprising a foamable styrene polymer containing a three component system and process of foaming

Claim 1

A COMPOSITION OF MATTER COMPRISED OF (A) 92-95 PARTS BY WEIGHT OF A STYRENE POLYMER, (B) 8-5 PARTS BY WEIGHT OF A FOAMING AGENT, AND (C) A MINOR AMOUNT OF A THREE-COMPONENT ADDITIVE SYSTEM SUFFICIENT TO CAUSE FINE CELL SIZE EHEN THE COMPOSITION IS EXTRUDED; SAID STYRENE POLYMER BEING SELECTED FROM THE GROUP CONSISTING OF STYRENE HOMOPOLYMERS AND STYRENE INTERPOLYMERS WHEREIN THE STYRENE INTERPOLYMERS CONTAIN A PREDOMINANT PROPORTION BY WEIGHT OF STYRENE WITH A BALANCE OF SAID INTERPOLYMER BEING SELECTED FROM THOSE ORGANIC MONOMERIC COMPOUNDS WHICH WILL INTERPOLYMERIZE WITH STYRENE MONOMER; SAID FOAMING AGENT BEING A VOLATILE, NON-REACTIVE ORGANIC COMPOUND WHICH HAS, AT MOST, A SLIGHT SOLVENT ACTION ON THE STYRENE POLYMER AND WHICH HAS A BOILING TEMPERATURE BETWEEN ABOUT 10*C. AND THE SOFTENING POINT OF THE STYRENE POLYMER; SAID THREE-COMPONENT ADDITIVE SYSTEM COMPRISING (1) AN ACID PHOSPHATE SALT SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL, ALKALINE EARTH METAL AND AMMONIUM POLYACID PHOSPHATES, (2) A NEUTRAL SALT OF AN ORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL AND ALKALINE EARTH MEAL SALTS OF MONOAND POLYCARBOXYLIC ACIDS, AND (3) A CARBON DIOXIDE LIBERATING AGENT SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL, ALKALINE EARTH METAL, AND AMMONIUM BICARBONATES AND CARBONATES; SAID COMPONENTS BEING PRESENT IN THE RATIO OF (1) 0.20-0.80 PART BY WEIGHT OF THE ACID PHOSPHATE SALT, (2) 0.50-1.00 PART BY WEIGHT OF THE NEUTRAL SALT OF AN ORGANIC ACID, AND (3) 0.20-0.60 PART BY WEIGHT OF THE CARBON DIOXIDE LIBERATING AGENT.