| abstract |
The refractory thermal insulation covering material 3 for the pipe 2 includes a polyisocyanate, a polyol, a trimerization catalyst, a foaming agent, a foam stabilizer and an additive. The additive is selected from the group consisting of red phosphorus; A foamed polyurethane insulation layer comprising a flame retardant urethane composition containing at least one selected from phosphoric acid ester, phosphate-containing flame retardant, bromine-containing flame retardant, boric acid-containing flame retardant, antimony-containing flame retardant, metal hydroxide and needle- have. |