Method for preparing flame-retardant and wear-resistant fibers for fireproof clothing by using regenerated polyester fibers

Abstract

The invention discloses a method for preparing flame-retardant and wear-resistant fibers for fireproof clothing by using regenerated polyester fibers, and belongs to the technical field of fiber processing, and the method specifically comprises the following steps: mixing polyester alcoholysate, a siloxane-based modifier, a catalyst and an additive, and carrying out condensation polymerization for 3-5 hours, namely modifying the polyester alcoholysate by using the siloxane-based modifier, and adding the additive into the polyester alcoholysate to obtain the flame-retardant and wear-resistant fibers for fireproof clothing. Regenerated polyester fibers with rigid frameworks and flexible networks are prepared through melt spinning and hot drafting, and then surface enhancement protection is performed through polypyrrole, so that the mechanical strength of the wear-resistant and flame-retardant fibers is effectively improved, and the wear resistance and flame retardance of the wear-resistant and flame-retardant fibers are also improved; and the composite material can be more easily applied to special fields such as fireproof suits.

Description

Technical Field

[0001] The invention relates to the technical field of fiber processing, and in particular to a method for preparing flame-retardant and wear-resistant fibers for fire-proof clothing by utilizing regenerated polyester fibers. Background Art

[0002] With the continuous advancement of industrial technology and people's increasing awareness of safety, fire-resistant clothing, as an important personal protective equipment, has increasingly stringent performance requirements. Especially in high-temperature, flammable or potential fire risk working environments, fire-resistant clothing must not only have excellent flame retardant properties, but also have sufficient wear resistance and comfort to ensure the wearer's life safety and work efficiency.

[0003] However, the regenerated polyester fiber in the prior art is mainly obtained by recycling discarded polyester products and reprocessing them into usable fiber materials through a series of treatment processes. This fiber not only helps to reduce the pollution of waste to the environment, but also effectively saves resources. However, the pure regenerated polyester fiber is still difficult to meet the needs of high-performance fire-resistant clothing in terms of flame retardancy and wear resistance. In order to improve the flame retardancy of regenerated polyester fiber, flame retardants are usually added during the fiber preparation process so that the fiber can quickly take effect when encountering a fire source to form a protective film to prevent the spread of flames. However, traditional flame retardants have problems such as poor compatibility with polyester matrix and low flame retardant efficiency. The large amount of flame retardant added will lead to a decrease in the mechanical strength of the regenerated polyester fiber. In addition, polyester fiber is prone to wear in high temperature and high friction environments, which also limits its application in special fields such as fire-resistant clothing. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing flame-retardant and wear-resistant fibers for fire-resistant clothing using regenerated polyester fibers, so as to solve the technical problem in the prior art that the mechanical strength, wear resistance and flame retardant properties of polyester fibers need to be further improved.

[0005] The purpose of the present invention can be achieved by the following technical scheme: A method for preparing flame retardant and wear resistant fiber for fireproof clothing by using regenerated polyester fiber, comprising the following steps:

[0006] S1, mixing the polyester alcoholysis product, the siloxane modifier, the catalyst I and the additive, carrying out polycondensation reaction for 3-5 hours at a temperature of 220-230° C. and a negative pressure of 10-100 Pa, and discharging the material while hot to obtain a composite polyester;

[0007] The synthetic reaction mechanism of composite polyester is:

[0008] During the reaction, the polyester alcoholysis product and the 1,2-ethylene glycol monoacetate modified on the siloxane modifier molecule are promoted by catalyst I to undergo ester exchange and condensation reactions, accelerate the formation of polyester chains, introduce polysiloxane chain segments into the composite polyester molecular chain, and obtain a composite polyester chain.

[0009] S2, mixing the composite polyester and the epoxy modified filler, melt spinning and then heat drawing to obtain the regenerated polyester fiber;

[0010] S3. Polypyrrole is deposited and coated on the outside of the regenerated polyester fiber through chemical deposition to obtain flame-retardant and wear-resistant fiber.

[0011] Furthermore, in step S1, the weight ratio of the polyester alcoholysis product, the siloxane modifier, the catalyst I and the additive is 90-100:20-30:2-3:3-5, the catalyst I is antimony trioxide, the additive is composed of a heat stabilizer, a matting agent and a lubricant in a weight ratio of 1:3:2, the heat stabilizer is one of phosphite and trimethyl phosphate, the matting agent is one of magnesium silicate, aluminum silicate and titanium dioxide, and the lubricant is stearate.

[0012] Furthermore, in step S2, the weight ratio of the composite polyester to the epoxy modified filler is 100:17-21, the melt spinning temperature is 245-255°C, the diameter of the spinneret hole is 0.3-0.5 mm, the hot stretching temperature is 160-180°C, and the hot stretching ratio is 5-6 times.

[0013] Furthermore, the preparation method of the polyester alcoholysis product is: in an inert gas atmosphere, waste polyester powder, ethylene glycol, and catalyst III are mixed, the temperature of the reaction system is increased to 190-195° C., and the reaction is kept warm for 3-5 hours, activated carbon is added to the reaction system, and the reaction is kept warm for 80-100 minutes, and post-processed to obtain the polyester alcoholysis product.

[0014] The synthetic reaction mechanism of polyester alcoholysis product is:

[0015] The main component of waste polyester powder is polyethylene terephthalate. When preparing polyester alcoholysis products, ethylene glycol is used as an alcoholysis agent. Under the action of high temperature and catalyst III, the ester bond in the polyester chain is broken to generate dihydroxyethyl terephthalate monomers or oligomers. Activated carbon is added during the reaction process to adsorb impurities and improve the purity of the product. The reaction system is mixed with water and then cooled to allow the alcoholysis product to crystallize and precipitate at low temperature to prepare the polyester alcoholysis product.

[0016] Furthermore, the amount ratio of the waste polyester powder, ethylene glycol, catalyst III and activated carbon is 100g:200mL:1g:5g, the catalyst III is zinc acetate, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is reduced to 150-160°C, filtered while hot, the filtrate and deionized water are mixed in a volume ratio of 1:2, the temperature of the reaction system is reduced to 3-8°C, stirred for 60-80min, filtered, the filter cake is washed three times with deionized water and then dried, the filter cake is transferred to a drying oven at a temperature of 60-70°C, and vacuum dried to constant weight to obtain a polyester alcoholysis product.

[0017] Furthermore, the preparation method of the flame retardant and wear resistant fiber is: pyrrole, regenerated polyester fiber and deionized water are mixed, stirred and dispersed for 30-50 minutes at room temperature, a catalyst solution is added dropwise to the reaction system, the reaction is kept warm for 3-5 hours, and post-processed to obtain the flame retardant and wear resistant fiber.

[0018] The synthetic reaction mechanism of flame retardant and wear-resistant fiber is:

[0019] During the reaction, the trivalent iron ions in the ferric chloride solution catalyze the oxidation of pyrrole monomers to generate pyrrole free radical cations. The pyrrole free radical cations and other pyrrole monomers undergo chain polymerization on the surface of the regenerated polyester fiber to generate a polypyrrole coating to prepare flame-retardant and wear-resistant fibers.

[0020] Furthermore, the dosage ratio of the pyrrole, regenerated polyester fiber, deionized water and catalyst solution is 1g:3g:10mL:0.5mL, the catalyst solution is composed of ferric chloride and deionized water at a ratio of 1g:10mL, and the post-treatment includes: after the reaction is completed, filtering, washing the filter cake with deionized water for 3 times and then drying, placing the filter cake in a drying oven at a temperature of 50-60°C, and vacuum drying to constant weight to obtain flame-retardant and wear-resistant fiber.

[0021] Further, the siloxane-based modifier is processed by the following steps:

[0022] A1. In an inert gas atmosphere, the modified DOPO, D4, toluene and catalyst II are mixed, the temperature of the reaction system is raised to 85-95°C, and the reaction is kept warm for 2-3 hours. A capping agent is added to the reaction system, and the reaction is kept warm for 60-80 minutes. After post-treatment, DOPO-modified polysiloxane is obtained;

[0023] A2. In an inert gas atmosphere, DOPO-modified polysiloxane, hydroxyethyl acrylate, toluene and initiator I are mixed, the temperature of the reaction system is raised to 70-80° C., the reaction is kept warm for 4-6 hours, and post-processed to obtain a siloxane-based modifier.

[0024] The synthetic reaction formula of the siloxane-based modifier is:

[0025]

[0026] In the formula

[0027] The synthetic reaction mechanism of the siloxane modifier is:

[0028] During the reaction, octamethylcyclotetrasiloxane (D4) undergoes a ring-opening polymerization reaction under the catalysis of formic acid to generate linear siloxane. At the same time, the siloxyethane bonds on the modified DOPO molecules are hydrolyzed to form silanol groups, which undergo dehydration condensation with the linear siloxane to generate Si-O-Si, thereby modifying DOPO to the polysiloxane chain. 1,1,3,3-tetramethyldisiloxane is used as a capping agent, which reacts with the silanol groups at the ends of the polysiloxane chains after hydrolysis to generate silanol-terminated modifications, thereby preparing DOPO-modified polysiloxane.

[0029] The hydroxyethyl acrylate free radical reacts with the silicon hydrogen on the DOPO modified polysiloxane chain under the action of initiator I to form 1,2-ethylene glycol monoacetate modification at the end of the DOPO modified polysiloxane to prepare a siloxane-based modifier.

[0030] Furthermore, in step A1, the amount ratio of the modified DOPO, D4, toluene, catalyst II and capping agent is 2g:7g:30mL:1.5mL:1g, the catalyst II is a 30-35wt% formic acid aqueous solution, the capping agent is 1,1,3,3-tetramethyldisiloxane, and the post-treatment includes: after the reaction is completed, the reaction system is kept at 85-95°C, and low-boiling substances are removed under reduced pressure to obtain DOPO-modified polysiloxane; in step A2, the amount ratio of the DOPO-modified polysiloxane, hydroxyethyl acrylate, toluene and initiator I is 2g:1g:20mL:0.05g, the initiator I is azobisisobutyronitrile, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is increased to 90°C, and low-boiling substances are removed under reduced pressure to obtain a siloxane-based modifier.

[0031] Furthermore, the preparation method of the modified DOPO is as follows: under an inert gas atmosphere, DOPO, diethoxymethylvinylsilane, toluene and initiator II are mixed, the temperature of the reaction system is increased to 70-80° C., the reaction is kept warm for 4-6 hours, and post-processed to obtain the modified DOPO.

[0032] The synthetic reaction formula of modified DOPO is:

[0033]

[0034] The synthetic reaction mechanism of modified DOPO is:

[0035] During the reaction, under the action of initiator II, the vinyl double bond on the diethoxymethylvinylsilane molecule reacts with the PH bond in the DOPO molecule to introduce diethoxymethylsilane into the DOPO molecule, thereby preparing modified DOPO.

[0036] The mass spectrometry analysis data of modified DOPO were: m / z: 390.14162 (100.0%), 391.14498 (21.6%), 391.14119 (5.1%), 392.13847 (3.3%), 392.14833 (2.2%), 392.14455 (1.1%).

[0037] Furthermore, the dosage ratio of DOPO and diethoxymethylvinylsilane is 1 mol:1.01 mol, the dosage ratio of DOPO, toluene and initiator II is 1 g:6 mL:0.02 g, the initiator II is azobisisobutyronitrile, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is increased to 90° C., and low-boiling substances are evaporated under reduced pressure to obtain modified DOPO.

[0038] Furthermore, the preparation method of the epoxy modified filler is as follows: nano-alumina, graphene, KH-560 and ethanol are mixed, ultrasonically dispersed for 30-50 minutes, the temperature of the reaction system is increased to 50-60°C, sodium hydroxide solution is added to the reaction system, the reaction is kept warm for 60-80 minutes, and post-processed to obtain the epoxy modified filler.

[0039] The synthetic reaction mechanism of epoxy modified filler is:

[0040] During the reaction, the trimethoxysilane group of KH-560 is hydrolyzed under alkaline conditions to generate silanol, which reacts with the surface active groups of nano-alumina or graphene particles to form siloxane bonds, forming KH-560 modifications on the nano-alumina and graphene particles to prepare epoxy-modified fillers.

[0041] Furthermore, the dosage ratio of the nano-alumina, graphene, KH-560, ethanol and sodium hydroxide solution is 5g:1g:2g:50mL:8mL, the concentration of the sodium hydroxide solution is 0.3-0.5mol / L, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until it is neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 60-70°C, and vacuum dried to constant weight to obtain an epoxy modified filler.

[0042] The present invention has the following beneficial effects:

[0043] 1. The flame-retardant and wear-resistant fiber for fire-proof clothing of the present invention is prepared by modifying polyester alcoholysis product with a siloxane-based modifier to prepare a composite polyester modified with polysiloxane, and then reinforcing and modifying the composite polyester with an epoxy-modified filler. After melt spinning, the orientation degree of the polyester molecular chain is improved by heat drawing, and the crystallinity and axial strength are improved to prepare a regenerated polyester fiber with "rigid skeleton + flexible network". By coating and modifying the regenerated polyester fiber with polypyrrole on the outside, a "surface enhancement + matrix protection" structure is formed, thereby improving the breaking strength and wear resistance of the wear-resistant and flame-retardant fiber. In addition, polypyrrole is carbonized at high temperature to form a dense carbon layer, which blocks the diffusion of heat and oxygen and improves the flame retardant effect of the condensed phase. It cooperates with the regenerated polyester fiber to further improve its flame retardant performance.

[0044] 2. The flame-retardant and wear-resistant fiber for fireproof clothing of the present invention is modified by epoxidation of inorganic fillers with KH-560, so that the inorganic fillers are more easily and evenly dispersed in the composite polyester. Under high temperature, the epoxy groups on the epoxy-modified filler molecules undergo ring-opening condensation with the active functional groups on the composite polyester molecules, thereby increasing the crosslinking degree of the molecules and improving the hardness and wear resistance of the regenerated polyester fiber. By introducing polysilane blocks into the regenerated polyester fiber, the polyester chain segments are given flexibility, the brittle fracture of the fibers caused by the crosslinking of the inorganic fillers is avoided, and the mechanical strength of the material is improved. In addition, the DOPO in the siloxane modifier is chemically bonded to the siloxane. During combustion, a dense silicon-phosphorus synergistic carbon layer is formed to block oxygen and heat, thereby improving the thermal stability and flame retardant properties of the recycled polyester fiber. Nano-alumina and two-dimensional lamellar graphene form a dense physical barrier layer at high temperatures, which delays the diffusion of heat and oxygen. Physical barriers delay heat transfer, inhibit thermal decomposition of the matrix, and further improve the heat resistance and flame retardant properties of the recycled polyester fiber. Polypyrrole coating can further block heat and oxygen, prevent the fiber matrix from being directly exposed to high temperature environments, enhance the flame retardant and high temperature resistance of the fiber material, and reduce fiber damage during friction, thereby further improving the wear resistance of the recycled polyester fiber. DETAILED DESCRIPTION

[0045] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the present application, waste polyester powder is waste PET powder with a particle size of 100-300 μm;

[0047] In the present application, DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, CAS number 35948-25-5;

[0048] In the present application, D4 is octamethylcyclotetrasiloxane, CAS number is 556-67-2;

[0049] In this application, the particle size of graphene is 0.8-80nm;

[0050] In this application, the particle size of nano-alumina is 10-15 nm;

[0051] In the present application, KH-560 is γ-glycidyloxypropyltrimethoxysilane, and its CAS number is 2530-83-8.

[0052] Example 1

[0053] This embodiment provides a method for preparing flame retardant and wear resistant fiber for fireproof clothing by using regenerated polyester fiber, comprising the following steps:

[0054] Step 1: Preparation of polyester alcoholysis product

[0055] Weigh: 500g of waste polyester powder, 1000mL of ethylene glycol, and 5g of zinc acetate are added to a nitrogen-protected reactor and stirred. After the reactor is sealed, the temperature is raised to 190°C and the reaction is kept warm for 3h. 25g of activated carbon is added to the reaction system and the reaction is kept warm for 80min. The temperature of the reactor is lowered to 150°C and filtered while hot. The filtrate and deionized water are mixed in another reactor at a volume ratio of 1:2. The temperature of the reactor is lowered to 3°C, and the mixture is kept warm and stirred for 60min. The filter cake is washed three times with deionized water and then dried. The filter cake is transferred to a drying oven at 60°C and vacuum dried to constant weight to obtain a polyester alcoholysis product.

[0056] Step 2: Preparation of silane-based modifier

[0057] Weigh: 43.2 g of DOPO, 32.4 g of diethoxymethylvinylsilane, 259.2 mL of toluene and 1.3 g of azobisisobutyronitrile, add into a three-necked flask protected by nitrogen and stir, raise the temperature of the three-necked flask to 70°C, keep the temperature for 4 h, raise the temperature of the three-necked flask to 90°C, remove low-boiling substances under reduced pressure, and obtain modified DOPO;

[0058] Weigh: 40 g of modified DOPO, 140 g of D4, 600 mL of toluene and 30 mL of 30 wt% formic acid aqueous solution, add into a three-necked flask protected by nitrogen, stir, raise the temperature of the three-necked flask to 85°C, keep warm for 2 h, add 20 g of 1,1,3,3-tetramethyldisiloxane into the three-necked flask, keep warm for 60 min, keep the three-necked flask at 85°C, remove low-boiling substances under reduced pressure, and obtain DOPO-modified polysiloxane;

[0059] Weigh: 160 g of DOPO modified polysiloxane, 80 g of hydroxyethyl acrylate, 1600 mL of toluene and 4 g of azobisisobutyronitrile, add into a three-necked flask protected by nitrogen and stir, raise the temperature of the three-necked flask to 70°C, keep warm and react for 4 hours, raise the temperature of the three-necked flask to 90°C, remove low boiling points under reduced pressure, and obtain a siloxane-based modifier.

[0060] Step 3: Preparation of composite polyester

[0061] The phosphite, magnesium silicate and calcium stearate are mixed in a weight ratio of 1:3:2 to obtain an additive auxiliary agent for later use;

[0062] Weigh by weight: 90 parts of polyester alcoholysis product, 20 parts of siloxane modifier, 2 parts of antimony trioxide and 3 parts of additive additives, add into the polycondensation reactor and stir, raise the temperature of the polycondensation reactor to 220°C, evacuate the negative pressure to 10Pa, carry out the polycondensation reaction for 3h, discharge the material while hot, and obtain a composite polyester.

[0063] Step 4: Preparation of regenerated polyester fiber

[0064] Weigh: 50g of nano-alumina, 10g of graphene, 20g of KH-560 and 500mL of anhydrous ethanol, add them into a three-necked flask, ultrasonically disperse them at room temperature for 30min, fix the three-necked flask on an iron stand with mechanical stirring, raise the temperature of the three-necked flask to 50°C, add 80mL of 0.3mol / L sodium hydroxide solution into the three-necked flask, keep the temperature for 60min, lower the temperature of the three-necked flask to room temperature, filter, wash the filter cake with purified water until it is neutral and then drain, transfer the filter cake to a drying oven at a temperature of 60°C, and vacuum dry it to constant weight to obtain an epoxy modified filler;

[0065] Weigh by weight: 100 parts of composite polyester and 17 parts of epoxy modified filler are mixed and added into a melt spinning machine with a temperature of 245°C and a spinneret hole diameter of 0.3 mm for melt spinning, and then the spinning is heat-stretched to 5 times the length at a temperature of 160°C to obtain regenerated polyester fiber.

[0066] Step 5: Preparation of wear-resistant flame-retardant fibers

[0067] Mix ferric chloride and deionized water at a ratio of 1 g:10 mL, and stir until the system is dissolved to obtain a catalyst solution for later use;

[0068] Weigh: 50 g of pyrrole, 150 g of regenerated polyester fiber and 500 mL of deionized water, add into a beaker and stir, stir and disperse at room temperature for 30 min, add 25 mL of catalyst solution dropwise into the beaker, keep warm for 3 h, filter, wash the filter cake with deionized water 3 times and then drain, place the filter cake in a drying oven at 50°C, and vacuum dry to constant weight to obtain flame retardant and wear-resistant fiber.

[0069] Example 2

[0070] This embodiment provides a method for preparing flame retardant and wear resistant fiber for fireproof clothing by using regenerated polyester fiber, comprising the following steps:

[0071] Step 1: Preparation of polyester alcoholysis product

[0072] Weigh: 500g of waste polyester powder, 1000mL of ethylene glycol, and 5g of zinc acetate are added to a nitrogen-protected reactor and stirred. After the reactor is sealed, the temperature is raised to 193°C and the reaction is kept warm for 4h. 25g of activated carbon is added to the reaction system and the reaction is kept warm for 90min. The temperature of the reactor is lowered to 155°C and filtered while hot. The filtrate and deionized water are mixed in another reactor in a volume ratio of 1:2. The temperature of the reactor is lowered to 5°C, and the mixture is kept warm and stirred for 70min. The filter cake is washed three times with deionized water and then dried. The filter cake is transferred to a drying oven at 65°C and vacuum dried to constant weight to obtain a polyester alcoholysis product.

[0073] Step 2: Preparation of silane-based modifier

[0074] Weigh: 43.2 g of DOPO, 32.4 g of diethoxymethylvinylsilane, 259.2 mL of toluene and 1.3 g of azobisisobutyronitrile, add into a three-necked flask protected by nitrogen and stir, raise the temperature of the three-necked flask to 75°C, keep the temperature for 5 h, raise the temperature of the three-necked flask to 90°C, remove low-boiling substances under reduced pressure, and obtain modified DOPO;

[0075] Weigh: 40 g of modified DOPO, 140 g of D4, 600 mL of toluene and 30 mL of 33 wt% formic acid aqueous solution, add into a three-necked flask protected by nitrogen, stir, raise the temperature of the three-necked flask to 90°C, keep warm for 2.5 h, add 20 g of 1,1,3,3-tetramethyldisiloxane into the three-necked flask, keep warm for 70 min, keep the three-necked flask at 90°C, and remove low-boiling substances under reduced pressure to obtain DOPO-modified polysiloxane;

[0076] Weigh: 160 g of DOPO modified polysiloxane, 80 g of hydroxyethyl acrylate, 1600 mL of toluene and 4 g of azobisisobutyronitrile, add into a three-necked flask protected by nitrogen and stir, raise the temperature of the three-necked flask to 75°C, keep warm and react for 5 hours, raise the temperature of the three-necked flask to 90°C, remove low boiling points under reduced pressure, and obtain a siloxane-based modifier.

[0077] Step 3: Preparation of composite polyester

[0078] The trimethyl phosphate, aluminum silicate and magnesium stearate are mixed in a weight ratio of 1:3:2 to obtain an additive auxiliary agent for later use;

[0079] Weigh by weight: 95 parts of polyester alcoholysis product, 25 parts of siloxane modifier, 2.5 parts of antimony trioxide and 4 parts of additive additives, add into the polycondensation reactor and stir, raise the temperature of the polycondensation reactor to 225°C, evacuate the negative pressure to 50 Pa, carry out the polycondensation reaction for 4 hours, discharge the material while hot, and obtain a composite polyester.

[0080] Step 4: Preparation of recycled polyester fiber

[0081] Weigh: 50g of nano-alumina, 10g of graphene, 20g of KH-560 and 500mL of anhydrous ethanol, add them into a three-necked flask, ultrasonically disperse them at room temperature for 40min, fix the three-necked flask on an iron stand with mechanical stirring, raise the temperature of the three-necked flask to 55°C, add 80mL of 0.4mol / L sodium hydroxide solution into the three-necked flask, keep warm and react for 70min, lower the temperature of the three-necked flask to room temperature, filter, wash the filter cake with purified water until it is neutral and then drain, transfer the filter cake to a drying oven at a temperature of 65°C, and vacuum dry it to constant weight to obtain an epoxy modified filler;

[0082] Weigh by weight: 100 parts of composite polyester and 19 parts of epoxy modified filler are mixed and added into a melt spinning machine with a temperature of 250°C and a spinneret hole diameter of 0.4 mm for melt spinning, and then the spinning is heat-stretched to 5.5 times the length at a temperature of 170°C to obtain regenerated polyester fiber.

[0083] Step 5: Preparation of wear-resistant flame-retardant fibers

[0084] Mix ferric chloride and deionized water at a ratio of 1 g:10 mL, and stir until the system is dissolved to obtain a catalyst solution for later use;

[0085] Weigh: 50 g of pyrrole, 150 g of regenerated polyester fiber and 500 mL of deionized water, add into a beaker and stir, stir and disperse at room temperature for 40 min, add 25 mL of catalyst solution dropwise into the beaker, keep warm and react for 4 h, filter, wash the filter cake with deionized water 3 times and then drain, place the filter cake in a drying oven at 55°C, and vacuum dry to constant weight to obtain flame retardant and wear-resistant fiber.

[0086] Example 3

[0087] This embodiment provides a method for preparing flame retardant and wear resistant fiber for fireproof clothing by using regenerated polyester fiber, comprising the following steps:

[0088] Step 1: Preparation of polyester alcoholysis product

[0089] Weigh: 500g of waste polyester powder, 1000mL of ethylene glycol, and 5g of zinc acetate are added to a nitrogen-protected reactor and stirred. After the reactor is sealed, the temperature is raised to 195°C and the reaction is kept warm for 5h. 25g of activated carbon is added to the reaction system and the reaction is kept warm for 100min. The temperature of the reactor is lowered to 160°C and filtered while hot. The filtrate and deionized water are mixed in another reactor at a volume ratio of 1:2. The temperature of the reactor is lowered to 8°C, and the mixture is kept warm and stirred for 80min. The filter cake is washed three times with deionized water and then dried. The filter cake is transferred to a drying oven at 70°C and vacuum dried to constant weight to obtain a polyester alcoholysis product.

[0090] Step 2: Preparation of silane-based modifier

[0091] Weigh: 43.2 g of DOPO, 32.4 g of diethoxymethylvinylsilane, 259.2 mL of toluene and 1.3 g of azobisisobutyronitrile, add into a three-necked flask protected by nitrogen and stir, raise the temperature of the three-necked flask to 80° C., keep the temperature for 6 h, raise the temperature of the three-necked flask to 90° C., remove low-boiling substances under reduced pressure, and obtain modified DOPO;

[0092] Weigh: 40 g of modified DOPO, 140 g of D4, 600 mL of toluene and 30 mL of 35 wt% formic acid aqueous solution, add into a three-necked flask protected by nitrogen, stir, raise the temperature of the three-necked flask to 95°C, keep warm for 3 h, add 20 g of 1,1,3,3-tetramethyldisiloxane into the three-necked flask, keep warm for 80 min, keep the three-necked flask at 95°C, remove low-boiling substances under reduced pressure, and obtain DOPO-modified polysiloxane;

[0093] Weigh: 160 g of DOPO modified polysiloxane, 80 g of hydroxyethyl acrylate, 1600 mL of toluene and 4 g of azobisisobutyronitrile, add into a three-necked flask protected by nitrogen and stir, raise the temperature of the three-necked flask to 80°C, keep warm and react for 6 hours, raise the temperature of the three-necked flask to 90°C, remove low boiling points under reduced pressure, and obtain a siloxane-based modifier.

[0094] Step 3: Preparation of composite polyester

[0095] The phosphite, nano titanium dioxide and zinc stearate are mixed in a weight ratio of 1:3:2 to obtain an additive, which is set aside;

[0096] Weigh by weight: 100 parts of polyester alcoholysis product, 30 parts of siloxane modifier, 3 parts of antimony trioxide and 5 parts of additive additives, add into the polycondensation reaction kettle and stir, raise the temperature of the polycondensation reaction kettle to 230°C, evacuate the negative pressure to 100 Pa, carry out the polycondensation reaction for 5 hours, discharge the material while hot, and obtain a composite polyester.

[0097] Step 4: Preparation of recycled polyester fiber

[0098] Weigh: 50 g of nano-alumina, 10 g of graphene, 20 g of KH-560 and 500 mL of anhydrous ethanol, add them into a three-necked flask, ultrasonically disperse them at room temperature for 50 min, fix the three-necked flask on an iron stand with mechanical stirring, raise the temperature of the three-necked flask to 60° C., add 80 mL of 0.5 mol / L sodium hydroxide solution into the three-necked flask, keep the temperature for reaction for 80 min, lower the temperature of the three-necked flask to room temperature, filter, wash the filter cake with purified water until it is neutral and then drain, transfer the filter cake to a drying oven at a temperature of 70° C., and vacuum dry it to constant weight to obtain an epoxy-modified filler;

[0099] Weigh by weight: 100 parts of composite polyester and 21 parts of epoxy modified filler, mix and add into a melt spinning machine with a temperature of 255°C and a spinneret hole diameter of 0.5 mm for melt spinning, then perform heat drawing of the spinning at a temperature of 180°C to 6 times the length to obtain regenerated polyester fiber.

[0100] Step 5: Preparation of wear-resistant flame-retardant fibers

[0101] Mix ferric chloride and deionized water at a ratio of 1 g:10 mL, and stir until the system is dissolved to obtain a catalyst solution for later use;

[0102] Weigh: 50 g of pyrrole, 150 g of regenerated polyester fiber and 500 mL of deionized water, add into a beaker and stir, stir and disperse at room temperature for 50 min, add 25 mL of catalyst solution dropwise into the beaker, keep warm for 5 h, filter, wash the filter cake with deionized water 3 times and then drain, place the filter cake in a drying oven at 60°C, and vacuum dry to constant weight to obtain flame retardant and wear-resistant fiber.

[0103] Comparative Example 1

[0104] The difference between this comparative example and Example 3 is that no modified DOPO is added to the DOPO-modified polysiloxane in step 2.

[0105] Comparative Example 2

[0106] The difference between this comparative example and Example 3 is that in step 4, graphene is not added.

[0107] Comparative Example 3

[0108] The difference between this comparative example and Example 3 is that in step 4, a mixture of nano-alumina and graphene in a weight ratio of 5:1 is used to replace the epoxy modified filler in the regenerated polyester fiber.

[0109] Comparative Example 4

[0110] The difference between this comparative example and Example 3 is that step five is eliminated, and the flame-retardant and wear-resistant fiber in step five is replaced by the regenerated polyester fiber in step four.

[0111] Performance Test:

[0112] The flame-retardant and wear-resistant fibers prepared in Examples 1-3 and Comparative Examples 1-4 were prepared into test samples by plain weaving;

[0113] The mass loss rates of the test samples prepared in Examples 1-3 and Comparative Examples 1-4 were measured with reference to the standard GB / T 21196.3-2007 “Determination of the abrasion resistance of textile fabrics by the Martindale method Part 3: Determination of mass loss”;

[0114] The breaking strength, breaking elongation and oxygen index of the wear-resistant flame-retardant fibers prepared in Examples 1-3 and Comparative Examples 1-4 were measured with reference to Standard FZ / T 52026-2012 “Regenerated flame-retardant polyester staple fibers”. The specific test results are shown in Table 1 below.

[0115] Table 1-Performance test data of the sample

[0116]

[0117] Data Analysis:

[0118] Comparing and analyzing the data in Table 1 above, the flame retardant and wear-resistant fiber prepared by the present invention has a breaking strength of 8.6 cN / detx, a breaking elongation of 24.3%, an oxygen index of 32%, and a wear resistance index of 2.425×10 4 times / mg, and all performance test data are better than those of the control example. The present invention modifies the polyester alcoholysis product by a siloxane-based modifier to prepare a composite polyester, and then reinforces and modifies the composite polyester with an epoxy-modified filler, prepares the regenerated polyester fiber by heat drawing after melt spinning, and then coats it with polypyrrole, which not only effectively improves the mechanical strength of the wear-resistant and flame-retardant fiber, but also improves the wear resistance and flame retardant properties of the wear-resistant and flame-retardant fiber.

[0119] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing flame retardant and wear-resistant fibers for fireproof clothing using regenerated polyester fibers, characterized in that: The following steps are involved: S1, mixing the polyester alcoholysis product, the siloxane modifier, the catalyst I and the additive, carrying out polycondensation reaction for 3-5 hours at a temperature of 220-230° C. and a negative pressure of 10-100 Pa, and discharging the material while hot to obtain a composite polyester; S2, mixing the composite polyester and the epoxy modified filler, melt spinning and then heat drawing to obtain the regenerated polyester fiber; S3. Polypyrrole is deposited and coated on the outside of the regenerated polyester fiber through chemical deposition to obtain flame-retardant and wear-resistant fiber.

2. The method for preparing flame retardant and wear resistant fiber for fire retardant clothing using regenerated polyester fiber according to claim 1, characterized in that: In step S1, the weight ratio of the polyester alcoholysis product, the siloxane modifier, the catalyst I and the additive is 90-100:20-30:2-3:3-5, the catalyst I is antimony trioxide, the additive is composed of a heat stabilizer, a matting agent and a lubricant in a weight ratio of 1:3:2, the heat stabilizer is one of phosphite and trimethyl phosphate, the matting agent is one of magnesium silicate, aluminum silicate and titanium dioxide, and the lubricant is stearate; in step S2, the weight ratio of the composite polyester and the epoxy modified filler is 100:17-21, the melt spinning temperature is 245-255°C, the pore size of the spinneret is 0.3-0.5mm, the hot drawing temperature is 160-180°C, and the hot drawing ratio is 5-6 times.

3. The method for preparing flame retardant and wear resistant fiber for fireproof clothing using regenerated polyester fiber according to claim 1, characterized in that: The preparation method of the flame retardant and wear resistant fiber comprises: mixing pyrrole, regenerated polyester fiber and deionized water, stirring and dispersing for 30-50 minutes at room temperature, dropping a catalyst solution into the reaction system, keeping the temperature for reaction for 3-5 hours, and post-treating to obtain the flame retardant and wear resistant fiber.

4. The method for preparing flame retardant and wear resistant fiber for fireproof clothing using regenerated polyester fiber according to claim 3, characterized in that: The dosage ratio of the pyrrole, the regenerated polyester fiber, the deionized water and the catalyst solution is 1g:3g:10mL:0.5mL, and the catalyst solution is composed of ferric chloride and deionized water in a ratio of 1g:10mL.

5. The method for preparing flame retardant and wear resistant fiber for fireproof clothing using regenerated polyester fiber according to claim 1, characterized in that: The siloxane-based modifier is processed by the following steps: A1. In an inert gas atmosphere, the modified DOPO, D4, toluene and catalyst II are mixed, the temperature of the reaction system is raised to 85-95°C, and the reaction is kept warm for 2-3 hours. A capping agent is added to the reaction system, and the reaction is kept warm for 60-80 minutes. After post-treatment, DOPO-modified polysiloxane is obtained; A2. In an inert gas atmosphere, DOPO-modified polysiloxane, hydroxyethyl acrylate, toluene and initiator I are mixed, the temperature of the reaction system is raised to 70-80° C., the reaction is kept warm for 4-6 hours, and post-processed to obtain a siloxane-based modifier.

6. The method for preparing flame retardant and wear resistant fiber for fire retardant clothing using regenerated polyester fiber according to claim 5, characterized in that: In step A1, the amount ratio of the modified DOPO, D4, toluene, catalyst II and capping agent is 2g:7g:30mL:1.5mL:1g, the catalyst II is a 30-35wt% formic acid aqueous solution, and the capping agent is 1,1,3,3-tetramethyldisiloxane; in step A2, the amount ratio of the DOPO modified polysiloxane, hydroxyethyl acrylate, toluene and initiator I is 2g:1g:20mL:0.05g, and the initiator I is azobisisobutyronitrile.

7. The method for preparing flame retardant and wear resistant fiber for fireproof clothing using regenerated polyester fiber according to claim 5, characterized in that: The preparation method of modified DOPO is as follows: under an inert gas atmosphere, DOPO, diethoxymethylvinylsilane, toluene and initiator II are mixed, the temperature of the reaction system is increased to 70-80° C., the reaction is kept warm for 4-6 hours, and post-processed to obtain modified DOPO.

8. The method for preparing flame retardant and wear resistant fiber for fireproof clothing using regenerated polyester fiber according to claim 7, characterized in that: The usage ratio of DOPO and diethoxymethylvinylsilane is 1 mol: 1.01 mol, the usage ratio of DOPO, toluene and initiator II is 1 g:6 mL:0.02 g, and the initiator II is azobisisobutyronitrile.

9. The method for preparing flame retardant and wear resistant fiber for fireproof clothing using regenerated polyester fiber according to claim 1, characterized in that: The preparation method of the epoxy modified filler is as follows: nano-alumina, graphene, KH-560 and ethanol are mixed, ultrasonically dispersed for 30-50 minutes, the temperature of the reaction system is increased to 50-60°C, sodium hydroxide solution is added to the reaction system, the reaction is kept warm for 60-80 minutes, and post-processed to obtain the epoxy modified filler.

10. The method for preparing flame retardant and wear resistant fiber for fireproof clothing by using regenerated polyester fiber according to claim 9, characterized in that: The dosage ratio of the nano-alumina, graphene, KH-560, ethanol and sodium hydroxide solution is 5g:1g:2g:50mL:8mL, and the concentration of the sodium hydroxide solution is 0.3-0.5mol / L.

Images