PURPOSE: To obtain a polyamide excellent in heat resistance, sliding property, etc., by polycondensing a hexamethylenediamine salt of an aromatic dicarboxylic acid component based on terephthalic acid or a lower condensate of this salt in a molten state at a specified temperature.
CONSTITUTION: An aromatic dicarboxylic acid mixture of 60W85mol% terephthalic acid and 40W15mol% aromatic dicarboxylic acids other than terephthalic acid (e.g., isophthalic acid) is reacted with hexamethylenediamine to form a hexamethylenediamine salt of the aromatic carboxylic acids or a lower condensate of this salt. Said salt or condensate is polycondensed at a temperature which is 340°C or below before the m.p. of the polycondensation reaction mixture in the polycondensation system reaches 300°C and is in the range of from the m.p. to the m.p. +40°C after the m.p. of the mixture exceeds 300°C to obtain the purpose polyamide.
ZENITANI YURIMASA
NAKANO TAKAYUKI
| US3941755A | 1976-03-02 |