Soft ethylenic polymer foams

US4101467A · kind A · utility

Assignee

• THE DOW CHEMICAL COMPANY · US

Inventors

• Chung P. Park · Baden-Baden, DE
• Warren H. Griffin · Saginaw, US
• John Corbett · Sydney, AU

Key dates

• Filing date: Jan 27, 1977
• Grant date: Jul 18, 1978
• Expiry date: Jan 27, 1997

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S264/05
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

Low density, closed cell, soft foam products having dimensional stability are made from ethylenic resins having low stiffness, especially comprising copolymers consisting essentially of ethylene and monoethylenically unsaturated non-ionic comonomers, by release to lower pressure of a flowable, foamable gel under pressure, e.g., by extrusion foaming, wherein the gel comprises the ethylenic polymer and a volatile mixed blowing agent. The stating polymers are preferably copolymers of ethylene and vinyl acetate having stiffness less than about 20,000 psi. The mixed blowing agents are particularly characterized as mixtures of at least one fluorocarbon constituent I and at least one fluorocarbon constituent II, as defined. Exemplary mixtures contain (I) 1,2-dichloro-1,1,2,2-tetrafluoroethane and (II) from 25 to 50 percent chloropentafluoroethane, octafluoropropane or octafluorocyclobutane based on the mixtures of I and II.