Marshall, O'Toole, Gerstein, Murray & Bicknell
Process for producing open-cell polyethylene foam materials and the resultant product
 This disclosure relates to a method for producing polyethylene open-cell foam materials, comprising a process step of pressurized heating at a temperature of 110.degree. to 135.degree. C. of a base compound consisting of polyethylene or a copolymer of polyethylene which has been compounded with an azodicarbonamide foaming agent and a bridging agent, in order to obtain a primary intermediate product with a cubical expansion coefficient of 1.0 to 2.0 times; a process step of heating the primary intermediate product under normal atmospheric pressure at a temperature of 150.degree..about.190.degree. C. and thus causing the complete decomposition of the foaming agent in order to obtain a secondary intermediate product having cell membranes capable of being easily ruptured by mechanical compression; and a process step of subjecting said secondary intermediate product to mechanical pressure in order to rupture and interconnect the closed cells; and, as needed, a foaming assist agent, or a high-melting-point resin powder, or both a high-melting-point resin powder and a foaming assist agent are added to and compounded with the base compound so that the resulting products are high-expansive or ultra-high-expansive materials with an expansion ratio of 25 times said base compound, or more, and have an open-cell ratio nof 96.about.100%. 
Kabushiki Kaisha Serutekuno
Y C Y C C Y C
Y10S C08J Y10S C08J C08J Y10S C08J
additional inventional additional inventional inventional additional additional
Hiroo
Ito