| 摘要 |
<p>Breathable thermoplastic polyurethanes are prepared from the reaction of a polyol component, a polyisocyanate component, and a chain extender in the presence of a metal-free catalyst. The metal-free catalyst comprises a polyalcohol amine, a tertiary amine catalyst, or a combination thereof. The polyurethanes of the present invention are suitable for film applications as they form breathable films which are permeable to water vapor but not air or water. The polyurethane compositions are substantially metal-free, have low extractables, and excellent melt strength.</p> |
