| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyamide-type polymer desirable as a material for moldings having a small dispersion of quality and being proof against polymerization in a molten state under industrially economical conditions by selecting a polymer specified in the relationships between the terminal amino contact A (meq/kg) and the terminal carboxyl content C (meq/kg). SOLUTION: This polymer satisfies the relationships of formulae I and II. A polymer- forming mixture is prepared by adding (x) mol of a monocarboxylic acid, (y) mol of a dicarboxylic acid, and (z) mol of a monoamine to 1,000 kg of a polyamide-forming monomer. This mixture is polymerized under conditions satisfying formula III (wherein (x), (y), and (z) are each 0 or a positive integer, provided that either (x) or (y) is a positive integer), and the liquid-phase-polymerized polymer is subjected to solid-phase polymerization at a temperature equal to or lower than its melting point so that the solid-phase-polymerized polymer may have a relative viscosity higher than that of the liquid-phase-polymerized polymer by at least 0.25+(a-c)/100 and may satisfies relationships I between the terminal amino content A and the terminal carboxyl content C. (a) is the terminal amino content of the liquid-phase-polymerized polymer, and (c) is the terminal carboxyl content of the liquid-phase-polymerized polymer.
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