| 摘要 |
A composition useful as a blowing agent having no flash point or reduced combustibility comprising 2-chloropropane and a gas selected from the group consisting of a fluorohydrocarbon, perfluorocarbons, fluoroethers, hydrofluoropolyethers and mixtures thereof is disclosed. A polyisocyanurate foam or a polyurethane modified polyisocyanurate foam having a mainly closed cell structure and also a method for preparing this foam, the latter comprising closed cells wherein a foam blowing agent consisting of a mixture of 2-chloropropane and one or more HFC compounds including pentafluoropropane, pentafluorobutane, heptafluoropropane, hexafluoropropane or pentafluoroethane are disclosed. Pentanes can be added if desired. Azeotropic mixtures in which 2~-chloropropane is an ingredient are disclosed.
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