| 摘要 |
1,260,272. Polyamide foams. FARBENFABRIKEN BAYER A.G. 8 Jan., 1970 [10 Jan., 1969], No. 961/70. Headings C3C and C3R. A polyamide foam is made by dissolving a gas under pressure in a molten polymerizable mixture of a lactam, e.g. #-caprolactam, a basic catalyst, e.g. sodium formate, and an activator, e.g. an organic diisocyanate, prepolymerizing the gasified mixture by passage under pressure through a tube whilst heating it to polymerization temperature, and releasing the pressure by discharging the mixture from the tube into a preheated or insulated mould in which the polymerization is completed. If polyisocyanates are used as the activator, polycarbodiimides are produced with splitting off of carbon dioxide, which acts as blowing agent. The dissolved gas may be carbon dioxide or nitrogen. In the examples the polymerizable mixture also contained silica gel and a polysilicone polyether block polymer (as pore regulator), and the activator was hexamethylene diisocyanate. |
