| 摘要 |
<p>A method for preparing polyurethane and polyisocyanurate foams which comprises reacting and foaming a mixture of ingredients which will react to form the polyurethane or polyisocyanurate foams in the presence of a blowing agent comprising a partially fluorinated alkane having four or five carbon atoms and a tertiary structure. The method is advantageous because partially fluorinated alkanes having a tertiary structure have zero ozone depletion potentials, are nonflammable, and have higher solvency toward polyols.</p> |
