Title: Polyurethane foam product and process of manufacture thereof from thermosetting frothed mixture

 Number/Link: US4216177

Applicant/Assignee: Rogers

Publication date: 5-08-1980

“Gist”: Frothed flexible foam

Why it is interesting: PORON is a popular brand of microcellular elastomeric/flexible polyurethane foams produced by Rogers Corporation. The original process, as documented in this patent, is quite simple:  a flexible foam formulation (in the examples) based on TDI, caprolacton diol, polymer polyol, some chain extender, amine catalyst and surfactant is frothed instead of blown with water or a physical blowing agent. The reacting froth is poured on release paper and heated to cure. Release paper can also be applied on top resulting in an integral skin on both sides of the layer. Frothing instead of blowing results in an improved compression set, different hardness-density relationship and a better control over cell structure. A unique material.

PORON foams