| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high-quality polymer from the solid-phase polymerization of a polyamide by subjecting a polyamide obtained by melt-polycondensing a diamine component containing at least a specified amount of m-xylylenediamine with a dicarboxylic acid component containing at least a specified amount of adipic acid to solid-phase polymerization so as to obtain a polymer having a specified relative viscosity and a specified difference between the concentrations of two types of terminal substituents. SOLUTION: A diamine component containing at least 80 wt.% m-xylylenediamine is melt- polycondensed with a dicarboxylic acid containing at least 80 wt.% adipic acid to form a polyamide having a relative viscosity (in 96% sulfuric acid at 25 deg.C) in the range represented by formula I, a difference between the concentrations of two types of terminal groups in the range represented by formula II, and a degree of crystallinity of at most 13%. The polyamide is heated to 60-150 deg.C in an atmosphere having an oxygen concentration of 5 vol.% and then heated to a temperature lower than the melting point by at least 15 deg.C in a vacuum of 500 Torr or lower after it reaches a degree of crystallinity of 15% to effect solid-phase polymerization for obtaining a polyamide having a relative viscosity in the range represented by formula III, a difference between the concentrations of two types of terminal groups in the range represented by formula II, and a number-average molecular weight of 19,500-50,000.
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