| 摘要 |
1328523 Polyamides DYNAMIT NOBEL AG 17 Sept 1970 [18 Sept 1969] 44536/70 Heading C3R Polyamides of terephthalic acid and a mixture of 2,2,4- and 2,4,4 - tri - methylhexamethylene diamine are prepared by a 3 stage process wherein (i) a precondensate is formed from dimethyl terephthalate and the diamines in the presence of water; (ii) the precondensate is polycondensed till the reduced specific viscosity (a 0À005 g/ml. cresol at 25‹ C. according to DIN 53 727) is 50 to 90; and (iii) further condensing in an extruder at 200‹ to 300‹ C. to give a polyamide of reduced specific viscosity of 116 to 150. The temperature is preferably 240‹ to 300‹ C. in the feed zone of the extruder and 10‹ to 20‹ C. lower in the end zone. The product is stated to be particularly suitable for blow moulding and to have a lower melting range and greater susceptibility to stabilizers than polymers obtained by polycondensing the precondensate in a single stage. Specified light stabilizers are 2-(2<SP>1</SP>-hydroxy-3<SP>1</SP>,5<SP>1</SP>-di-tbutyl- or -5<SP>1</SP> - methyl - phenyl) - benzotriazole, 2 - hydroxy - 4 - n - octoxy- or 2,2<SP>1 </SP>- dihydroxy- 4 - methoxy - benzophenone, are 4,4<SP>1 </SP>- dihydrodiphenyl - 2,2 - propane. They may be mixed with a granulate of the polymer which may have a melting range of 167‹ to 195‹ C. and a Vicat dimensional stability of 150Œ5. Reference has been directed by the comptroller to Specification 1,212,776 |
