| abstract |
The present invention is a process for foaming thermoplastic polymer comprising polystyrene, said process comprising forming a molten foamable composition comprising said thermoplastic polymer, block copolymer, and blowing agent comprising at least one of Z-1,1,1,4,4,4 hexafluoro-2-butene and E-1,1,1,4,4,4-hexafluoro-2-butene and expanding said foamable composition to obtain as a result thereof foamed thermoplastic polymer, the process being preferably carried out by extruding the composition in molten form, whereupon the foaming of the thermoplastic polymer occurs. |