| 摘要 |
Linear, high-mol, polyesters are stabilised by addn of a thiourea of formula: (where R1-4 are H or is not >15C alkyl or aryl residues. The polyester is protected against thermal and oxidative breakdown during and after prepn., and does not become discoloured. The polyesters are esp. derived from 5-10C alkene dicarboxylic acids or benzene or naphthalene dicarboxylic acids, and 2-6C alkane diols. The polyester esp. contains is not 50 (70-100) moles % polyethylene terephthalate or polybutylene terephthalate. In I, in partic., the R gp gps. are H, 1-4C (un)branched alkyl, or phenyl gp. opt. substd. with 1-4C alkyl gps.; more esp., is not 2 of the R gps. are H. Suitable stabilisers include N,N'-dimethylthiourea, N,N'-diphenylthiourea and N-methyl-N-phenylthiourea. The amt. of I is 0.01-1 (0.05-0.5) wt.%. The stabiliser may be added before (pref.), during or after the polycondensation. The polyester can be moulded or injection moulded, formed into fibres, films, and wire and cable jackets, calendered to sheets or plates, or calendered onto fabric and other substrates. |
