Method for preparing improved expanded polystyrene sheet
AssigneeArco Polymers, Inc.
InventorJohn P. Spicuzza, Jr.
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Abstract
Expanded styrene polymer sheet material is produced by extruding expandable and/or general purpose styrene polymer with a conventional blowing agent, a nucleating system and a small amount of finely divided hydrophobic silicon dioxide. The resulting product has very fine, uniformly sized pores and improved flexibility.
Claims11
In a process for producing microcellular expanded styrene polymer sheet by extruding a mixture containing styrene polymer, a blowing agent and a nucleating system, the improvement comprising extruding with said mixture about 0.002 to 2%, based on the total weight of styrene polymer, of hydrophobic silica, said hydrophobic silica being uniformly distributed throughout said mixture whereby said sheet has improved flexability.
A process of extruding expanded styrene polymer sheet having a small and uniform cell size from styrene polymer feedstock comprising extruding a mixture comprised of the styrene polymer, about 3-10% blowing agent, about 0.01 to 5% nucleating system, and about 0.002 to 2% hydrophobic silica having an average particle size of about 1 to 100 millimicrons, said percentages being based on the total weight of styrene polymer being extruded.
Dependencies are inferred from the claim text.