| 摘要 |
1,273,367. Preparing microcrystalline polyesters. FMC CORP. 16 Sept., 1969 [17 Sept., 1968], No. 45484/69. Heading C3R. Finely divided microcrystalline polyesters (e.g. polyethylene terephthalate or bisphenol A polycarbonate) capable of forming a stable colloidal dispersion are obtained by hydrolysing the polyester in a liquid medium having a mild swelling action on the polyester (e.g. ethylacetate, ethylene glycol or water) and then mechanically disintegrating the hydrolysed polyester. The hydrolysing agent is preferably a base, such as sodium hydroxide, urea, ethylene diamine or n.propylamine. Prior to hydrolysis the crystallinity of the polyester may be increased by heating it under nitrogen or in dimethyl silicone. The polyester may be mixed with miorocrystalline starch, cellulose or nylon for use in the production of moulding powders. |
