Achilles Corporation

Yoshiyuki Ohnuma

Junichiro Mori

Hideki Tosaki

Norio Tanaka

The present invention relates to a preparation method for low-density polyurethane foam excelling in the flame retardance and the dimensional stability, wherein rigid polyurethane foam having the average value for the ratio of lengthwise direction diameter/cross direction diameter of cells being 1.0 to 1.4 and the density of 20 to 40 kg/mis prepared by combining, as blowing agent, carbon dioxide generated in the reaction between water and polyisocyanate and carbon dioxide under supercritical state, subcritical state or liquid state, and by adding said water and said carbon dioxide under liquid state into said polyol component prior to mixing the polyisocyanate component and the polyol component, and to rigid polyurethane foam obtained by said method.

Preparation method for rigid polyurethane foam

A process for producing a urethane-modified polyisocyanurate foam comprises mixing a polyisocyanate component, a polyl component containing an aromatic polyester polyol, a catalyst, a foaming agent, a surfactant and other additives under high pressure in a mixing head and then spraying the resultant mixture to expand the foaming ingredient therein. The process uses, as the catalyst, at least three compounds of N,N',N'-tris(dimethylaminopropyl)-S-hexahydrotriazine, an alkali metal carboxylate and a lead compound in combination.

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Ashikaga, Japan

Yoshiyuki Ohnuma