Halogen-free flame-retarding nylon-6 preparation method

The invention relates to the field of organic high-molecular materials and particularly relates to a halogen-free flame-retarding nylon-6 preparation method which includes following steps: (1) filling a container with a certain amount of a caprolactam monomer; (2) heating the container, vacuumizing the container and removing water from the container; (3) adding a catalyst and stirring the mixture for a certain time uniformly; (4) adding proper amount of ammonium polyphosphate, organic silicon and magnesium hydroxide powder with stirring uniformly; (5) adding an activating agent with stirring uniformly and rapidly pouring the mixture into a pre-heated die; (6) performing constant-temperature polymerization for a certain time and demoulding the semi-product to finally obtain a halogen-free flame-retarding MC nylon composite material. The preparation method is quick in synthetic speed and is toxic-free, is safe and pollution-free and satisfies green chemical requirements. The composite material is better in wear resistance. Compared with a common physical melt blending modification method, the halogen-free flame-retarding in-situ polymerization modification method enables a flame-retarding agent to disperse uniformly without aggregation in a nylon base material, so that the composite material is durable in flame retardant effect and is stable and excellent in mechanical performances.