| 摘要 |
Polyurethane foams blown with a mixture of water, HCFC-22 or HCFC-141b, and a perfluorinated hydrocarbon having from 3 to 8 carbon atoms yields polyurethane and polyisocyanurate foams having exceptional physical properties, i.e., small and uniform cells, low initial K-factor, low aged K-factor, and high tensile strength. The low initial and aged K-factors are most unexpected when it is considered that significant amounts of water are used to blow the foam.
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