| 摘要 |
<p>1439964 Crystallizing polycarbonates UNIBRA 13 July 1973 [27 July 1972 26 Feb 1973] 33582/73 Heading C3R A process for crystallizing a polycarbonate comprises mixing a finely divided nucleating agent selected from inorganic salts of organic acids with the polycarbonate and crystallizing the mixture at a temperature higher than the vitreous transition temperature, i.e. the minimum temperature at which the polymer will crystallize from the polymer-containing mixture. The nucleating agent is preferably used in an amount of from 0À01 to 20% by weight, based on the total composition, and preferably has an average grain size lower than 5 microns. The semi-crystalline polycarbonate obtained by the above process may be used as a nucleating agent for the crystallization of a second batch of polycarbonate. The preferred polycarbonate is that derived from bisphenol A and various nucleating agents are specified, e.g. K, Na, Zi and Zn benzoate and Na benzene sulphinate. In the examples, the semi-crystalline polycarbonate obtained by the above process (i) is used as a nucleating agent together with a trimellitic ester plasticizer for a further batch of polycarbonate, and (ii) is reinforced with glass fibres.</p> |
