The invention relates a nylon 6
polymerization method and a direct
spinning method of a melt of a
polymer obtained with the nylon 6
polymerization method. A
polyamide 6
prepolymer is prepared at the low temperature, the content of oligomers in the melt is controlled in advance,
polymerization is completed before a large quantity of cyclic oligomers are generated with a condensation polymerization dynamic strengthening method, a nylon 6
polymer melt with certain molecular weight is acquired, the content of extracts in the product is smaller than or equal to 1.5 wt%, and the content of cyclic dipolymers is smaller than or equal to 0.2wt%; then, direct
melt spinning forming is performed after condensation polymerization dynamic strengthening ends. The process is simple,
energy consumption is further reduced while the
utilization rate of
caprolactam is increased, the obtained melt can be directly used for
melt spinning, high-capacity large-scale production is easy to realize, a modifier can be added in the polymerization process, flexible production of nylon 6 is realized, and the nylon 6 can be applied to fibers for clothes, industrial filaments,
engineering plastics and other fields.