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CN-122013347-A - High-quality copolymerized flame-retardant nylon 66 fiber and preparation method thereof

CN122013347ACN 122013347 ACN122013347 ACN 122013347ACN-122013347-A

Abstract

The invention discloses a high-quality copolymerized flame-retardant nylon 66 fiber and a preparation method thereof, which are characterized in that a reactive phosphorus flame retardant [ (6-oxo-6H-dibenzo [ C, E ] [1,2] oxaphosphorin-6-yl) methyl ] succinic acid (DDP) or 3-hydroxyphenyl phosphoryl propionic acid (CEPPA) and aliphatic diamine are adopted to prepare flame retardant salt, the flame retardant salt is used as a flame-retardant unit to be copolymerized with the nylon 66 salt, and a chain extender (at least one selected from epoxy chain extender and bisoxazoline chain extender), a compound stabilizer (a hindered phenol antioxidant and phosphite heat stabilizer combination) and a dispersing agent (aliphatic amide or wax) are synchronously added in the polymerization process, and then solid-phase tackifying and melt spinning are carried out to prepare the target fiber. The flame retardant grade of the fiber prepared by the method reaches UL-94V-0 level, no molten drop exists, the breaking strength is more than or equal to 4.5cN/dtex, the breaking elongation is 25% -30%, and the fiber has excellent flame retardant property and mechanical property.

Inventors

  • SUN YANLU
  • LV WANGYANG
  • BAI YUFAN

Assignees

  • 浙江理工大学

Dates

Publication Date
20260512
Application Date
20260323

Claims (10)

  1. 1. The high-quality copolymerized flame-retardant nylon 66 fiber is characterized by being prepared from the following raw materials in parts by mass through copolymerization reaction: 92-100 parts of nylon 66 salt; 2-7 parts of flame retardant salt; 0.2-2 parts of chain extender; 0.1-1 part of compound stabilizer; 0.2-1 parts of a dispersing agent; the flame retardant salt is prepared by salifying reaction of a reactive phosphorus flame retardant and aliphatic diamine.
  2. 2. The high-quality copolymerized flame-retardant nylon 66 fiber according to claim 1, wherein the reactive phosphorus flame retardant is [ (6-oxo-6H-dibenzo [ C, E ] [1,2] oxaphosphorin-6-yl) methyl ] succinic acid (DDP) or 3-hydroxyphenyl phosphoryl propionic acid (CEPPA), and the aliphatic diamine has a structural formula of H 2 N-(CH 2 ) x -NH 2 , wherein x is an integer of 4-10.
  3. 3. The high-quality copolymerized flame-retardant nylon 66 fiber according to claim 1, wherein the chain extender is at least one selected from the group consisting of a styrene-glycidyl methacrylate copolymer-based epoxy chain extender and a bisoxazoline-based chain extender.
  4. 4. The high-quality copolymerized flame-retardant nylon 66 fiber according to claim 3, wherein the styrene-glycidyl methacrylate copolymer-based epoxy chain extender is Joncryl ADR series, and the bisoxazoline-based chain extender is at least one selected from the group consisting of 2,2' -bis (2-oxazoline) (BOZ), 1, 3-bis (2-oxazolinyl) benzene (PBO), and 1, 4-bis (2-oxazolinyl) benzene (PBOX).
  5. 5. The high-quality copolymerized flame-retardant nylon 66 fiber according to claim 1, wherein the compound stabilizer is formed by combining a hindered phenol antioxidant and a phosphite ester heat stabilizer, and the dispersing agent is an aliphatic amide or wax dispersing agent.
  6. 6. The high-quality copolymerized flame-retardant nylon 66 fiber according to claim 5, wherein the hindered phenol antioxidant is an antioxidant 1010 or 1076, the phosphite heat stabilizer is an antioxidant 168 or 626, and the dispersant is Ethylene Bis Stearamide (EBS) or oxidized polyethylene wax (OPE).
  7. 7. The high-quality copolymerized flame-retardant nylon 66 fiber according to any one of claims 1 to 6, wherein the fiber has a breaking strength of 4.5 cN/dtex or more, an elongation at break of 25% to 30%, and a flame retardant rating of UL 94V-0.
  8. 8. A process for preparing the high quality copolymerized flame-retardant nylon 66 fiber of any one of claims 1 to 7, comprising the steps of: (1) The preparation method comprises the steps of (1) carrying out salt formation reaction on a reactive phosphorus flame retardant and aliphatic diamine in a polar solvent to prepare a flame retardant salt; (2) The nylon 66 salt, the flame retardant salt prepared in the step (1), the chain extender, the compound stabilizer, the dispersing agent and the deionized water are added into a polymerization kettle to carry out copolymerization reaction to obtain the copolymerization flame retardant nylon 66 with a flame retardant structure; (3) Carrying out solid-phase tackifying treatment on the copolymerization flame retardant nylon 66 obtained in the step (2); (4) And (3) carrying out melt spinning on the tackified copolymerized flame-retardant nylon 66 slice to obtain the copolymerized flame-retardant nylon 66 fiber.
  9. 9. The preparation method of the catalyst according to claim 8, wherein the specific process conditions of the copolymerization reaction in the step (2) are that after the air in the kettle is replaced by nitrogen, the temperature is raised to 210-220 ℃, the pressure is kept at 1.8-2.0 MPa, the polycondensation is carried out for 2-3 hours, then the temperature is raised to 245-255 ℃, the pressure is reduced to normal pressure within 0.5-1 hour, finally the temperature is raised to 270-280 ℃, the vacuum pumping is carried out until the pressure is 50-200 Pa, and the heat preservation and the pressure maintaining are carried out for 1-3 hours.
  10. 10. The preparation method of claim 8, wherein the solid phase adhesion temperature in the step (3) is 160-220 ℃ and the time is 4-24 hours, the melt spinning temperature in the step (4) is 280-295 ℃, the winding speed is 2500-3500 m/min, and the draft multiple is 3.0-4.5.

Description

High-quality copolymerized flame-retardant nylon 66 fiber and preparation method thereof Technical Field The invention belongs to the field of nylon fiber preparation, and particularly relates to a high-quality copolymerized flame-retardant nylon 66 fiber and a preparation method thereof. Background Nylon 66 (polyhexamethylene adipamide) is an important engineering plastic and synthetic fiber raw material, and is widely applied to the fields of automobiles, electronics and electrics, textile clothing, special protection and the like because of high strength, high wear resistance, chemical corrosion resistance and good processing performance. The PA66 fiber has excellent mechanical properties, high strength, wear resistance, impact resistance, fatigue resistance, excellent thermal stability, resistance to corrosion of organic solvent and weak acid and alkali, good spinnability, easy dyeing, blending with natural fibers, moderate hygroscopicity, stable size, difficult deformation, and suitability for various scenes such as high-strength textiles, industrial consumables, clothing fabrics and the like. However, nylon 66 has a Limiting Oxygen Index (LOI) of only about 22-24%, belongs to inflammable materials, can generate molten drops in the combustion process, is extremely easy to ignite other substances and causes fire spread, and severely limits the application of the nylon 66 in high-end occasions with flame retardant requirements (such as aerospace interiors, firefighters, special industrial fabrics and the like). The introduction of the flame retardant is an effective way for improving the flame retardance of the nylon material, and at present, the flame retardant nylon material is prepared in two main modes, namely a blending mode, wherein the flame retardant is added into a nylon matrix to prepare flame retardant nylon, and a copolymerization mode, wherein the flame retardant with flame retardant groups is combined with nylon 66 salt through a series of reactions to prepare the intrinsic flame retardant nylon. In preparing high-orientation, high-strength fibers, it is desirable that the polymer melt have suitable viscoelastic properties. In order to obtain high performance nylon, techniques of high molecular weight nylon or high viscosity nylon have been studied and developed. Firstly, the molecular weight is improved through polycondensation reaction, and secondly, the viscosity is improved through modification methods such as grafting, crosslinking, chain extension and the like. The molecular chain end of nylon contains amino and carboxyl, and has certain reactivity under certain conditions, which provides a basis for chemical chain extension. Epoxy compounds, bisoxazoline compounds, isocyanate and the like are added into nylon, and the difunctional compounds contain functional groups which are easy to react with carboxyl and amino groups, can directly react with nylon low molecular weight oligomers, form bridging between two polymer chains, obviously increase molecular weight, improve viscosity of a system and reduce end group content. Chinese patent CN105131280a discloses a halogen-free flame retardant nylon 66 resin and its preparation method, which uses phosphine oxide diacid and common diamine to prepare organic phosphorus ammonium salt as flame retardant component to copolymerize with nylon salt. In order to solve the problem that the flame retardant in nylon 66 is decomposed due to overhigh temperature in the polymerization and processing process, 0-0.2 part by mass of antioxidant is added, and the halogen-free flame-retardant copolymerized nylon 66 resin with high viscosity, no molten drop and high mechanical property is prepared. Disclosure of Invention The invention aims to overcome the defects of the prior art, solve the defects of flammability and melt dripping during combustion of nylon 66 fibers, and simultaneously improve the problems of the traditional flame retardant modification method (the mechanical property loss is large, the traditional copolymerization method is easy to decompose the flame retardant at high temperature, the thermal stability and spinnability of the fibers are difficult to consider), and the preparation method of the fiber product with excellent flame retardant property, high mechanical strength, good thermal stability and excellent spinning property is provided by adopting the copolymerization of organic phosphazenium salt prepared from the reactive phosphorus flame retardant diacid and the common diamine as flame retardant components and the nylon salt. In a first aspect, the invention provides a high-quality copolymerized flame-retardant nylon 66 fiber, which is prepared from the following raw materials in parts by mass through copolymerization reaction: 92-100 parts of nylon 66 salt; 2-7 parts of flame retardant salt, wherein the flame retardant salt is prepared by salifying reaction of a reactive phosphorus flame retardant and aliphatic diamine; 0.2-2 parts o