| 摘要 |
<p>The present invention relates to blowing agent compositions for polymeric foams that contain carbon dioxide and a hydrofluorocarbon having a boiling point of 14°C or higher and lower than 120°C. The present invention also relates to processes for preparing polymeric foam using such blowing agent compositions, foamable polymer compositions containing such blowing agents, and polymeric foams containing such blowing agent compositions. Suitable blowing agent combinations include: (a) a composition containing carbon dioxide and at least one hydrofluorocarbon having a boiling point of 30°C to 120°C that is essentially free of other low boiling ethers and hydrocarbons; (b) a composition containing greater than 50 weight-percent carbon dioxide and at least one hydrofluorocarbon having a boiling point of 14°C or higher to 120°C; and (c) carbon dioxide and one hydrofluorocarbon having a boiling point of 14°C or higher and lower than 120°C.</p> |
