To provide a rigid polyurethane foam which has an excellent applicability and shows an excellent flame retardance after expansion curing, and a heat-insulation treatment process for an articles using the foam, which meets the requirements for flame retardance and is unaffected by the ambient temperature.
This rigid polyurethane foam comprises a polyol component mainly comprising a resol resin and/or benzyl ether type phenol resin and an aromatic polyol, and a polyisocyanate as essential components, is obtained by allowing these two essential components to react in the presence of a curing catalyst, a foam stabilizer and a foaming agent. Here, the proportion of the resol resin and/or benzyl ether type phenol resin blended in the polyol component is from 10 to 50 wt.%, and the proportion of the aromatic polyol blended in the polyol component is from 20 to 90 wt.%. The curing catalyst contains a tertiary amine catalyst and an acid block type temperature-sensitive catalyst comprising a carboxylic acid salt of a tertiary amine.
SUGANO KAZUNORI
HATTORI YASUNORI
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