The present invention relates to a
polymer material, more particularly to a
low melting point and high
decomposition temperature ternary copolyamide produced without a ring-opening agent. According to the present invention, the problem that the
caprolactam polymerization process is limited by the ring-opening agent (the conventional
polymerization reaction usually adopts water and
aminocaproic acid as ring-opening agents) is solved, wherein in order to ensure the ring-opening
reaction rate, a lot of water is required to be added at the reaction early stage so as to cause problems such as water removing difficulty at the reaction later stage,
high energy consumption, and influence of not complete water removing on the product quality; the low molecular weight extractable product content of the
polyamide 6 prepared through the conventional
polymerization is more than 9%, the extraction and re-
drying process is required before the
processing so as to provide the long process and increase the product cost, the low molecular weight extractable product content of the product of the present invention is only 1-5% so as to eliminate the extraction re-
drying and
monomer recovery process, and the
caprolactam conversion rate is substantially improved so as to save the cost; and the problems of high
melting point and difficult
processing of
polyamide are solved, and the shortcomings of the prior art are overcome.