Copolymerized flame-retardant polyamide and preparation method thereof

Abstract

The invention relates to copolymerized flame-retardant polyamide and a preparation method thereof. The preparation method comprises the following steps: mixing a flame retardant salt with a polyamide6 oligomer and / or a polyamide 66 oligomer, and carrying out condensation polymerization to obtain copolymerized flame-retardant polyamide. The flame retardant salt is prepared from a DOPO derivative and diamine NH2R2NH2 through a high-temperature and high-pressure reaction. The temperature of the high temperature is 200-250 DEG C, and the pressure of the high pressure is 1.2-1.8 MPa. The structural formula of the finally obtained copolymerized flame-retardant polyamide is as follows. In the structural formula, x is the polymerization degree of the polyamide 6 oligomer, y is the polymerizationdegree of the polyamide 66 oligomer, and the structural formula of Rz is as follows. The preparation method disclosed by the invention is simple to operate, and the prepared product has excellent flame retardance, good impact resistance and processability.

Description

Technical field[0001]The invention belongs to the technical field of flame-retardant polyamide synthesis, and relates to a copolymerized flame-retardant polyamide and a preparation method thereof, in particular to a new preparation method of flame-retardant salt, and a preparation method of triblock phosphorus-containing copolymer flame-retardant polyamide .Background technique[0002]Polyamide 6 and polyamide 66 are the two varieties with the largest output and the most widely used in polyamide products. They are also widely used engineering plastics. They have high mechanical strength, good wear resistance, and good solvent resistance. However, the impact resistance of polyamide 6 is low; while polyamide 66 has a high melting point and a narrow processing temperature range, which limits the application of both in certain fields. Therefore, polyamide 6 and polyamide 66 are copolymerized and modified by the melt copolymerization method to prepare polyamide 6 / 66 composite materials, wh...

AI Technical Summary

Problems solved by technology

The fabric finishing method is mainly aimed at the flame retardant modification of polyamide fabrics. The main disadvantages are that it is not resistant to washing, has poor hand feeling, and affects the dyeing performance of the fabric; the blending method is to blend polyamide chips and flame retardants through mechanical melting. A method of preparing flame-retardant polyamide materials, the main disadvantage is that the flame retardant is added in a large amount and unevenly distributed, which has a great impact on the mechanical properties of the material; the copolymerization method is to use the flame retardant as a comonomer to participate in the melting Polycondensation uses chemical bonds to introduce the main chain or branch of polyamide macromolecules. This method not only adds less amount, but also has little effect on other properties of polyamide, and has a long-lasting flame retardant effect. It is an ideal flame retardant modification method.

The polyamide 6 / 66 composite material is usually prepared by twin-screw blending of polyamide 6 and polyamide 66 slices, but because the melting points of polyamide 6 and polyamide 66 are very different, the two materials are easy to mix unevenly, resulting in composite The comprehensive performance of the material is reduced, but the polyamide 6 / 66 prepared by the copolymerization method does not have this shortcoming, and the comprehensive performance of the material has been improved, especially the processing performance

[0005] Chinese patents (publication numbers CN106633043A, CN106675007A, CN106832911A, CN106633828A, etc.) all prepare flame-retardant polyamide materials by copolymerization. When preparing flame-retardant salts, they are carried out at low temperature (60-90°C) and normal pressure, and their reactivity is low. When the amount of flame retardant is large, the molecular weight of the polymer is seriously reduced, and under this condition, the flame retardant monomer and the diamine are not connected by covalent bonds, so the flame retardant salt is easily destroyed during the later polymerization process. thereby affecting the aggregation process

Chinese patent (publication number CN109852042A) uses additive-type DOPO derivatives as flame retardants to prepare PA6 / PA66 composite materials through twin-screw blending, and because the melting points of polyamide 6 and polyamide 66 differ greatly, the PA6 prepared by this method The overall performance of the / PA66 composite material is not reliable. Secondly, the flame retardant is dispersed in the material in a physical state. If it is further processed into fibers, the flame retardant effect of the product will not last long.

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