| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyamide resin composition free from impurities such as agglomerates and having an increased degree of polymerization by adding a specified amount of water to a lower polyamide condensate, crystallizing the condensate at a temperature lower than the glass transition temperature of the condensate, and subjecting the crystallized condensate to solid phase polymerization at a temperature lower than the melting point by specified degrees. SOLUTION: A lower polyamide condensate is uniformly moistened with water by e.g. spraying to a moisture content (%) >=(Tg-50)/12 to lower its glass transition temperature, and crystallized by cooling to the glass transition temperature or below. Next, the crystallized condensate is dried, if necessary, and subjected to solid phase polymerization at a temperature lower than the melting point by 10-150 deg.C to obtain a polyamide resin. This resin is mixed with a filler, a glass fiber, additives, and other resins. The lower polyamide condensate has a melting point of 280 deg.C or above, a relative viscosity of 1.05-2.0, and a heat of cooling crystallization of 5 J/g or above between the glass transition temperature and the melting temperature in DSC measurement and is exemplified by nylon 46, nylon 6T, nylon 6N, nylon M6, or nylon MT.
|
