| abstract |
A process is provided for preparing a thermoplastic polymer foam, comprising providing a foamable composition comprising a thermoplastic polymer and a blowing agent, wherein the blowing agent comprises from 10% to 60% by weight Z-1,1,1, 4,4,4- hexafluoro-2-butene (Z-HFO-1336mzz) and from 40% to 90% by weight 1,1-difluoroethane (HFC-152a), and wherein said thermoplastic polymer comprises polystyrene homopolymer, a polystyrene copolymer, styrene-acrylonitrile copolymer, or blends thereof, and expanding said foamable composition to produce a closed cell, smooth skin polymer foam having a density of less than 42 kg/ m 3 . Also disclosed is a thermoplastic polymer foam composition comprising a thermoplastic polymer selected from the group consisting of polystyrene homopolymer, a polystyrene copolymer, styrene-acrylonitrile copolymer, or blends thereof, defining a plurality of cells having an average cell size, and a blowing agent comprising from 10% to 60% by weight Z-1,1,1,4,4,4-hexafluoro-2-butene (Z- HFO-1336mzz) and from 40% to 90% by weight 1,1-difluoroethane (HFC-152a), having a density of less than 42kg/m 2 , according to ISO method 845-85, wherein the thermoplastic polymer has a melt flow rate of less than 25 g/10 min. |