Permanent-flame-retardant nylon 6 material and preparation method therefor

Abstract

The invention relates to a permanent-flame-retardant nylon 6 material and a preparation method therefor and particularly relates to a preparation method for a block copolymerized flame-retardant nylon 6 material obtained through continuously and respectively carrying out two-step polymerization reaction on a phosphoric reactive flame retardant. The method is characterized by comprising the steps of firstly enabling the flame retardant to react with diamine or dibasic alcohol so as to obtain a flame retardant prepolymer, and then, enabling the flame retardant prepolymer to react and copolymerize with a prepolymer of nylon 6, thereby obtaining the permanent-flame-retardant nylon 6 material. The flame-retardant nylon 6 material prepared by the method has the characteristics of low flame retardant addition level and durable flame-retardant effect, the limiting oxygen index is over 30%, the vertical firing test reaches UL94V-0, and the mechanical properties are excellent; and the nylon 6 material can be subjected to injection molding directly or form films and can also become into fibers so as to further prepare flame-retardant fabrics.

Description

technical field [0001] The invention belongs to the technical field of flame retardant nylon synthesis, and relates to a permanent flame retardant nylon 6 material and a preparation method thereof, in particular to a prepolymerized material containing a flame retardant obtained by block copolymerization through continuous and separately carried out two-step polymerization reactions. A permanent flame-retardant nylon 6 material and a preparation method thereof. Background technique [0002] Nylon is one of the most important engineering plastics, and nylon 6 is the most widely used variety in nylon. Nylon 6 has excellent properties such as good wear resistance, deformation resistance, resilience and low temperature resistance, and can be made into fibers, films, engineering plastics, etc., but the limiting oxygen index of nylon 6 is 21-22%, and its flame retardancy is not good Ideal, severely limits the application of nylon 6. Therefore, it is of great significance to study...

AI Technical Summary

Problems solved by technology

[0003] At present, there are three main methods for the flame retardant modification of polymer materials: first, the use of additive flame retardants. For nylon 6, flame retardants are mainly added to nylon 6 to achieve flame retardant modification. It is characterized by convenient use and wide application, but it has a great influence on the mechanical properties of materials

Second, use a reactive flame retardant, that is, the flame retardant participates in the reaction as a reactive monomer, and the flame retardant is combined with the main chain or side chain of nylon to make it have a flame retardant component. This method is less toxic , long-lasting flame retardant performance, and little impact on the performance of materials, but there are few types of reactive flame retardants, complex processing technology, and high cost. Currently, no additive flame retardants are commonly used

Third, flame retardant fabric finishing. Nylon 6 fabrics can obtain flame retardant effects by combining flame retardants with fabrics through flame retardant finishing, such as grafting, rolling baking, spray coating, etc. It is characterized by simple process, Easy to operate and flexible in processing, but may cause loss of fabric strength and affect its feel and washability

However, there are also shortcomings in the flame retardant modification of copolymerization. On the one hand, the introduction of flame retardants will inevitably affect the polymerization process of polymer materials, resulting in a decrease in molecular weight, which will inevitably affect its mechanical properties and affect its use effect; on the other hand , usually copolymerization flame retardant modification is to directly polymerize the flame retardant and nylon monomer to obtain a random copolymer of nylon and flame retardant. The flame retardant is randomly distributed in nylon. For random copolymers, with As the concentration of non-crystalline comonomer (flame retardant) increases, the melting point decreases monotonously. We are faced with the problem of not only needing a certain amount of flame retardant modification to obtain flame retardant nylon, but also maintaining the high temperature resistance of nylon. contradictory, which limits the use of nylon

In the modification of other polymers, there is no direct polycondensation, but the flame retardant is pretreated and crushed with the polymer material to block the polymer material during the blending process, and then the molecular weight is increased through solid-state polycondensation However, this method has disadvantages such as uneven distribution of flame retardants in polymer materials, low probability of flame retardants being bound to polymer main chains, and impact on the mechanical properties of materials.

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