Back to results
US 4,020,025 AGranted
Extrudable foamable composition comprising an olefin polymer, a styrene polymer and a hydrogenated styrene butadiene block copolymer
AssigneeBASF SE
InventorsGerhard Zeitler, Heinz Mueller-Tamm
Life of this patent
Estimating the term…
Abstract
Foams of mixtures of polyolefins and styrene polymers are produced by mixing the polymers with low-boiling expanding agents in the presence of a hydrogenated styrene/butadiene block polymer or a graft polymer of styrene on a polyolefin at temperatures above the softening point of the polymer mixture and under a pressure which prevents foaming of the mixture, followed by extrusion of the foamable mixture into a zone of lower pressure. The resulting foams are resistant to organic solvents.
Claims8
Extrusion-foamable composition of polyolefins and styrene polymers, which comprises a mixture of
- a. 5 to 90% by weight of ethylene or propylene polymers,
- b. 10 to 95% by weight of styrene polymer,
- c. 0.5 to 10% by weight, based on the combined weight of polyolefin (a) and styrene polymer (b), of a hydrogenated styrene/butadiene block polymer and
- d. 5 to 30% by weight, based on the combined weight of polyolefin (a) and styrene polymer (b), of at least one low-boiling expanding agent, said styrene polymer (b) having a higher molecular weight, measured by the melt index, than that of the polyolefin (a) and is finely dispersed in the polyolefin (a) forming the continuous phase, and said hydrogenated styrene/butadiene block polymer (c) having a viscosity average moleclar weight of from 3,000 to 800,000.
1 more element
Dependencies are inferred from the claim text.