| 摘要 |
During the catalytic hardening of polyurethanic moulding masses, which contain diisocyanates and polyalcohols and/or polyurethanic prepolymers, sorbic acid or cinnamic acid is used as catalyser. These acids produce a quick prehardening and hence a good withdrawing from the mould, which allows to increase the rate of production. Furthermore, these acids are physiologically acceptable, which enables to apply this process of preparation to the shaping of medical instruments. These acids can also be used in a physiologically acceptable mixture with a catalyst containing metals having a high atomic weight. |
