Bornitridhaltige thermoplastische Polyesterformmassen

1289576 Polyester compositions comprising boron nitride FARBWERKE HOECHST AG 29 July 1970 [29 July 1969] 36640/70 Heading C3R A thermoplastic moulding composition comprises a mixture of (a) a linear saturated polyester of an aromatic dicarboxylic acid and optionally up to 10% by weight of aliphatic dicarboxylic acids, based on the total weight of acids, with a saturated aliphatic or cycloaliphatic diol, (b) 0À005 to 5% of the total composition weight of boron nitride and (c) 0À005 to 5% of the total composition weight of one or more compounds containing a S-O-Na or P-O-Na group. Components (b) and (c) may be added during the preparation of the polyester or may be added to the preformed polyester and mixed in by granulation. The composition may be subjected to solid-phase polymerization to compensate for degradation of the polyester during mixing. The boron nitride preferably has a particle size below 10 Á and is heated at 800‹ C. for 1-24 hr. before use. Other polymers may also be included, e.g. ethylene-acrylic ester, ethylene vinyl acetate or butadiene-styrene copolymers. The examples describe compositions of polyethylene terephthalate and boron nitride with (1) sodium sulphate; (2) and (3) sodium alkanesulphonate (C 13-18 ), (4) sodium alkenesulphonate, R-CH = CH-SO 3 Na (R = C 15-18 alkyl), (5) sodium p-toluenesulphonate, (6) sodium diphenylphosphinate, (7) disodium ethylphosphonate, (8) disodium n-dodecylphosphonate and (9) the disodium salt of phosphoric acid mono-n-dodecyl ester. Reference has been directed by the Comptroller to Specification 1,246,770.