| 摘要 |
<p>This invention relates to the use of a C2-6 polyfluorocarbon compound containing non chlorine or bromine atoms as physical blowing agent in the preparation of rigid, closed-cell, polymer foams. Use of such blowing agents in the preparation of polyurethane foam provides for a product in which the loss in thermal insulationperformance with time compared to products prepared in absence of such blowing agent is reduced.</p> |
