The present invention relates to a process for the production of particles from solutions or melts of heat-activatable polyurethanes by
i) dissolving a compressible auxiliary agent at a pressure of between 50 and 1000 bar into a conveyable solution or melt of a heat-activatable polyurethane to obtain a mixture of polyurethane, compressible auxiliary agent and optionally solvent,
ii) optionally adjusting of the temperature of the resulting mixture to a temperature of from 40° K below to 150° K above the crystallite melting point of the polyurethane,
iii) expanding the mixture by means of an expansion device into a container, while adjusting the temperature in the container to at least 5° K below the softening temperature of the polyurethane to maintain the open jet particles in a form in which they do not agglomerate, and
iv) separating the formed particles from the stream of decompressed compressible auxiliary agent and optionally solvent.
本发明涉及一种利用可热激活的聚
氨酯溶液或熔体生产颗粒的工艺,其方法是
i) 在 50 至 1000 巴的压力下,将可压缩的辅助剂溶解到可输送的热活化聚
氨酯溶液 或熔体中,以获得聚
氨酯、可压缩的辅助剂和可选溶剂的混合物、
ii) 将所得混合物的温度调节至低于聚
氨酯晶体熔点 40°K 至高于其晶体熔点 150°K 的温度、
通过膨胀装置将混合物膨胀到一个容器中,同时将容器中的温度调节到至少比聚
氨酯软化温度低 5° K,以保持开放式喷射颗粒不会聚集,以及
iv) 从减压的可压缩辅助剂和溶剂流中分离已形成的颗粒。