Fireproof flame-retardant fiber and preparation method thereof

Abstract

The invention discloses a fireproof flame-retardant fiber and a preparation method thereof, and relates to the field of fibers. The preparation method comprises the following steps: reacting beta-cyclodextrin with allyl succinic anhydride to prepare terminated beta-cyclodextrin during preparation of the fireproof and flame-retardant fiber; the preparation method comprises the following steps: reacting polyether amine with beta-cyclodextrin to prepare polypseudorotaxane; the polypseudorotaxane and the end-capped beta-cyclodextrin are subjected to a reaction, and polyrotaxane is prepared; the preparation method comprises the following steps: carrying out a reaction on polyrotaxane and allyl dichlorophosphine to prepare modified polyrotaxane; carrying out hydrolytic condensation on dimethoxymethylsilane to prepare an organic silicon monomer; reacting the polyester prepolymer with an organic silicon monomer to prepare modified polyester; and carrying out melt spinning on the modified polyester and the modified polyrotaxane. The fireproof flame-retardant fiber prepared by the invention has good flame retardant property, hydrophilic moisture absorption property and mechanical property.

Description

Technical Field

[0001] The invention relates to the field of fibers, in particular to a fire-resistant and flame-retardant fiber and a preparation method thereof. Background Art

[0002] Polyester fiber is a synthetic fiber made of organic dibasic acid and diol by chemical polycondensation. It is a kind of polymer compound and the most important one among synthetic fibers. Polyester fiber has many advantages. Polyester fiber has the advantages of not easy to wrinkle, good resistance to most chemicals, and good chemical corrosion resistance; Polyester fiber is easy to dye and process, and has low cost. It has good application prospects and market economic value. It is widely used in textile and clothing manufacturing and other fields, bringing a lot of convenience and comfort to our daily life.

[0003] However, polyester fiber is a flammable material. Once ignited by a fire source, it burns violently and is difficult to extinguish, posing a huge threat to people's lives and property. Therefore, flame-retardant polyester fiber materials are gradually entering the market. Polyester fiber lacks hydrophilic groups and has poor hydrophilic hygroscopicity, which greatly limits the application of polyester fiber in fabrics. The fire-retardant fiber prepared by the present invention has good hydrophilicity, flame retardant properties and mechanical properties, and has good market prospects. Summary of the invention

[0004] The purpose of the present invention is to provide a fire-retardant fiber and a preparation method thereof to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A fireproof and flame-retardant fiber, which is prepared by reacting β-cyclodextrin with allyl succinic anhydride to obtain blocked β-cyclodextrin; reacting polyetheramine with β-cyclodextrin to obtain polypseudorotaxane; reacting polypseudorotaxane and blocked β-cyclodextrin to obtain polyrotaxane; reacting polyrotaxane with allylphosphine dichloride to obtain modified polyrotaxane; hydrolyzing and condensing dimethoxymethylsilane to obtain organosilicon monomer; reacting polyester prepolymer and organosilicon monomer to obtain modified polyester; and melt spinning the modified polyester and modified polyrotaxane to obtain the fireproof and flame-retardant fiber.

[0006] A method for preparing a fire-retardant fiber comprises the following steps: (1) β-cyclodextrin, allyl succinic anhydride, p-toluenesulfonic acid and toluene are mixed in a mass ratio of 1: (0.6-0.8): (0.04-0.06): (20-30), stirred at 30-40°C and 400-600 r / min for 1.5-2.5 h, filtered, washed the filter residue with deionized water for 3-5 times, and vacuum dried at 75-85°C for 4-6 h to obtain capped β-cyclodextrin; (2) Adding polyetheramine at a rate of 20-40 drops / min into a saturated β-cyclodextrin aqueous solution with a mass of 25-30 times that of the polyetheramine, stirring at 400-600 r / min for 1.5-2.5 h at 20-30 °C, letting stand for 10-14 h, filtering, washing the filter residue with deionized water for 3-5 times, and freeze-drying in vacuum for 8-12 h to obtain polypseudorotaxane; adding capped β-cyclodextrin, polypseudorotaxane, N-hydroxysuccinimide, carbodiimide, N , N-dimethylformamide is mixed in a mass ratio of 1: (4-6): (0.04-0.06): (0.04-0.06): (10-14), stirred at 400-600 r / min at room temperature, adjusted to pH 5.5-6.5 with 0.1 mol / L hydrochloric acid solution, continued to react for 1-2 hours, filtered, washed the residue with deionized water for 3-5 times, and vacuum dried at 75-85°C for 4-6 hours to obtain a polyrotaxane; (3) Mix polyrotaxane, allylphosphine dichloride and pyridine in a mass ratio of 1: (2-4): (40-50), stir at 400-600 r / min for 3-5 h at 8-12 °C, add saturated copper sulfate solution 8-12 times the mass of pyridine, let stand for 10-14 h, filter, wash the residue with saturated copper sulfate solution and deionized water for 3-5 times, respectively, and vacuum dry at 75-85 °C for 4-6 h to obtain a modified polyrotaxane; (4) Dimethoxymethylsilane and toluene are mixed in a mass ratio of 1: (8-12), and deionized water 3-5 times the mass of dimethoxymethylsilane is added dropwise at a rate of 2-4 ml / min. After the addition is completed, the mixture is stirred at 400-600 r / min for 25-35 min at 45-55 °C, allowed to stand for 25-35 min, the organic phase is separated, and distilled under reduced pressure at 80-90 °C to obtain an organosilicon monomer; polyester prepolymer, organosilicon monomer, sodium hydroxide and toluene are mixed in a mass ratio of 1: (0.2-0.4): (0.02-0.04): (8-12), stirred at 240-270 °C and 400-600 r / min for 3-5 h under a nitrogen atmosphere, washed with deionized water for 3-5 times, and vacuum dried at 75-85 °C for 4-6 h to obtain a modified polyester; (5) The modified polyester, modified polyrotaxane and azobisisobutyronitrile are mixed in a mass ratio of 1: (0.2-0.4): (0.04-0.06), melt-extruded through a twin-screw extruder, allowed to stand at 140-160°C for 2-4 hours under nitrogen protection, spun, and cooled to room temperature through a side-blown air tunnel to obtain fibers. The fibers are immersed in ammonia water at room temperature for 1-2 hours, taken out, and dried at 105-115°C for 4-6 hours to obtain fire-retardant fibers.

[0007] As an optimization, the polyetheramine in step (2) is D230 type polyetheramine.

[0008] As an optimization, the method for preparing the saturated β-cyclodextrin aqueous solution in step (2) is: mix β-cyclodextrin and deionized water in a mass ratio of 1:10, stir at 200 r / min at 60°C for 2 h, and take the upper layer of liquid to obtain the solution.

[0009] As an optimization, the polyester prepolymer preparation method in step (4) is as follows: polyethylene terephthalate, ethylene glycol and zinc acetate are mixed in a mass ratio of 1: (2.8-3.2): (0.01-0.02), stirred and refluxed at 200-210°C and 600-800 r / min for 1-2 h in a nitrogen atmosphere, cooled to 80-90°C, filtered with deionized water for 3-5 times, the filtrate is cooled at 0°C and allowed to stand for 22-24 h, filtered, and the residue is dried at 70-80°C for 4-6 h to obtain the product.

[0010] As an optimization, the process parameters of the twin-screw extruder in step (5) are as follows: the temperature of the first zone of the twin-screw extruder is 265-275°C, the temperature of the second zone is 265-275°C, the temperature of the third zone is 270-280°C, the temperature of the fourth zone is 270-280°C, and the head temperature is 265-275°C.

[0011] As an optimization, the spinning process parameters of step (5) are: spinning specification 150D / 48f, spinning box temperature 280-290°C, spinneret aperture 0.28mm, spinneret aperture aspect ratio 2, and winding speed 3000m / min.

[0012] Compared with the prior art, the beneficial effects achieved by the present invention are: When preparing the fireproof and flame-retardant fiber, the present invention comprises the following steps: reacting beta-cyclodextrin with allyl succinic anhydride to obtain end-capped beta-cyclodextrin; reacting polyetheramine with beta-cyclodextrin to obtain polypseudorotaxane; reacting polypseudorotaxane and end-capped beta-cyclodextrin to obtain polyrotaxane; reacting polyrotaxane with allylphosphine dichloride to obtain modified polyrotaxane; hydrolyzing and condensing dimethoxymethylsilane to obtain organosilicon monomer; reacting polyester prepolymer with organosilicon monomer to obtain modified polyester; and melt spinning the modified polyester and the modified polyrotaxane to obtain the fireproof and flame-retardant fiber.

[0013] First, polyetheramine penetrates the cavity of β-cyclodextrin and is embedded in β-cyclodextrin through the host-guest force to obtain polypseudorotaxane, and β-cyclodextrin modified with allyl succinic anhydride is terminated with polypseudorotaxane through amidation reaction of amino and carboxyl groups to obtain polyrotaxane. The hydrophobic and hydrophilic properties of β-cyclodextrin and the hydrophilic properties of polyetheramine make polyrotaxane have good hydrophilic properties, which improves the hydrophilic and hygroscopic capacity of fire-retardant fiber. The long chain structure of polyetheramine and the hydroxyl group of β-cyclodextrin can form hydrogen bonds and ether bonds through molecular self-assembly, which improves the binding force with β-cyclodextrin, thereby improving the mechanical properties of fire-retardant fiber.

[0014] Secondly, polyethylene terephthalate is hydrolyzed with ethylene glycol and then ester-exchanged with silicone monomers to introduce a silicon-hydrogen structure into the polyester material, which can form a denser residual carbon structure and improve the flame retardant and mechanical properties of the fire-retardant fiber. The surface of the polyrotaxane is modified with allyl phosphine dichloride to contain phosphorus, which can promote carbonization and isolate flames and has a good flame retardant effect. The introduced double bonds and the silicon-hydrogen bonds on the modified polyester form a stable cross-linked structure under the action of the initiator, thereby improving the mechanical properties of the fire-retardant fiber. DETAILED DESCRIPTION

[0015] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0016] Example 1

[0017] A method for preparing a fire-retardant fiber comprises the following steps: (1) β-cyclodextrin, allyl succinic anhydride, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 1:0.6:0.04:20, stirred at 400 r / min for 1.5 h at 30 °C, filtered, washed the filter residue with deionized water for 3 times, and vacuum dried at 75 °C for 4 h to obtain capped β-cyclodextrin; (2) Add polyetheramine to a saturated β-cyclodextrin aqueous solution with a mass 25 times that of polyetheramine at a rate of 20 drops / min, stir at 400 r / min at 20°C for 1.5 h, let stand for 10 h, filter, wash the filter residue with deionized water for 3 times, and freeze-dry in vacuum for 8 h to obtain polypseudorotaxane; mix capped β-cyclodextrin, polypseudorotaxane, N-hydroxysuccinimide, carbodiimide, and N,N-dimethylformamide in a mass ratio of 1:4:0.04:0.04:10, stir at 400 r / min at room temperature, adjust the pH to 5.5 with 0.1 mol / L hydrochloric acid solution, continue the reaction for 1 h, filter, wash the filter residue with deionized water for 3 times, and dry in vacuum at 75°C for 4 h to obtain polyrotaxane; (3) Mix polyrotaxane, allylphosphine dichloride and pyridine in a mass ratio of 1:2:40, stir at 400 r / min at 8°C for 3 h, add saturated copper sulfate solution 8 times the mass of pyridine, let stand for 10 h, filter, wash the filter residue with saturated copper sulfate solution and deionized water for 3 times, respectively, and vacuum dry at 75°C for 4 h to obtain a modified polyrotaxane; (4) Dimethoxymethylsilane and toluene were mixed in a mass ratio of 1:8, and deionized water 3 times the mass of dimethoxymethylsilane was added dropwise at a rate of 2 ml / min. After the addition was completed, the mixture was stirred at 400 r / min for 25 min at 45°C, allowed to stand for 25 min, the organic phase was separated, and distilled at 80°C under reduced pressure to obtain an organosilicon monomer; polyethylene terephthalate, ethylene glycol, and zinc acetate were mixed in a mass ratio of 1:2.8:0.01, and distilled at 200°C under a nitrogen atmosphere. The mixture was stirred and refluxed at 600 r / min for 1 h, cooled to 80°C, filtered with deionized water for 3 times, the filtrate was cooled at 0°C and allowed to stand for 22 h, filtered, and the filter residue was dried at 70°C for 4 h to obtain the obtained product; the polyester prepolymer, silicone monomer, sodium hydroxide and toluene were mixed at a mass ratio of 1:0.2:0.02:8, stirred at 240°C and 400 r / min for 3 h under a nitrogen atmosphere, washed with deionized water for 3 times, and vacuum dried at 75°C for 4 h to obtain the modified polyester; (5) The modified polyester, modified polyrotaxane and azobisisobutyronitrile were mixed in a mass ratio of 1:0.2:0.04, and melt-extruded through a twin-screw extruder. The temperature of the first zone, the temperature of the second zone, the temperature of the third zone, and the temperature of the fourth zone were 265°C. The head temperature of the twin-screw extruder was 265°C. The mixture was allowed to stand at 140°C for 2 h under nitrogen protection. The mixture was spun on a spinning machine with a spinning specification of 150D / 48f, a spinning box temperature of 280°C, a spinneret aperture of 0.28 mm, a spinneret aperture aspect ratio of 2, and a winding rate of 3000 m / min. The mixture was cooled to room temperature through a side-blowing air tunnel to obtain fibers. The fibers were immersed in ammonia water at room temperature for 1 h, taken out, and dried at 105°C for 4 h to obtain fire-retardant fibers.

[0018] Example 2 A method for preparing a fire-retardant fiber comprises the following steps: (1) β-cyclodextrin, allyl succinic anhydride, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 1:0.7:0.05:25, stirred at 35°C and 500 r / min for 2 h, filtered, the filter residue was washed with deionized water for 4 times, and vacuum dried at 80°C for 5 h to obtain capped β-cyclodextrin; (2) Add polyetheramine at a rate of 30 drops / min into a saturated β-cyclodextrin aqueous solution with a mass 27 times that of the polyetheramine, stir at 500 r / min at 25°C for 2 h, let stand for 12 h, filter, wash the filter residue with deionized water for 4 times, and freeze-dry in vacuum for 10 h to obtain polypseudorotaxane; mix capped β-cyclodextrin, polypseudorotaxane, N-hydroxysuccinimide, carbodiimide, and N,N-dimethylformamide in a mass ratio of 1:5:0.05:0.05:12, stir at 500 r / min at room temperature, adjust the pH to 6 with 0.1 mol / L hydrochloric acid solution, continue the reaction for 1.5 h, filter, wash the filter residue with deionized water for 4 times, and vacuum dry at 80°C for 5 h to obtain polyrotaxane; (3) Mix polyrotaxane, allylphosphine dichloride and pyridine in a mass ratio of 1:3:45, stir at 500 r / min for 4 h at 10°C, add saturated copper sulfate solution 10 times the mass of pyridine, let stand for 12 h, filter, wash the filter residue with saturated copper sulfate solution and deionized water for 4 times, respectively, and vacuum dry at 80°C for 5 h to obtain a modified polyrotaxane; (4) Dimethoxymethylsilane and toluene were mixed in a mass ratio of 1:10, and deionized water with a mass of 4 times that of dimethoxymethylsilane was added dropwise at a rate of 3 ml / min. After the addition was completed, the mixture was stirred at 500 r / min for 30 min at 50°C, allowed to stand for 30 min, the organic phase was separated, and distilled under reduced pressure at 85°C to obtain an organosilicon monomer; polyethylene terephthalate, ethylene glycol, and zinc acetate were mixed in a mass ratio of 1:3:0.015, and distilled under a nitrogen atmosphere at 205°C for 7 00r / min stirring and reflux for 1.5h, cool to 85℃, filter with deionized water 4 times, cool the filtrate at 0℃ and let stand for 23h, filter, and dry the filter residue at 75℃ for 5h to obtain; polyester prepolymer, silicone monomer, sodium hydroxide and toluene are mixed in a mass ratio of 1:0.3:0.03:10, stirred at 255℃ and 500r / min for 4h under nitrogen atmosphere, washed with deionized water 4 times, and vacuum dried at 80℃ for 5h to obtain modified polyester; (5) The modified polyester, modified polyrotaxane and azobisisobutyronitrile were mixed in a mass ratio of 1:0.3:0.05, and melt-extruded through a twin-screw extruder. The temperature of the first zone, the temperature of the second zone, the temperature of the third zone, and the temperature of the fourth zone were 270°C, and the temperature of the die head was 270°C. Under nitrogen protection, the mixture was allowed to stand at 140°C for 2 h. The mixture was spun on a spinning machine with a spinning specification of 150D / 48f, a spinning box temperature of 285°C, a spinneret aperture of 0.28 mm, a spinneret aperture aspect ratio of 2, and a winding rate of 3000 m / min. The mixture was cooled to room temperature through a side-blowing air tunnel to obtain fibers. The fibers were immersed in ammonia water at room temperature for 1 h, taken out, and dried at 105°C for 4 h to obtain fire-retardant fibers.

[0019] Example 3

[0020] A method for preparing a fire-retardant fiber comprises the following steps: (1) β-cyclodextrin, allyl succinic anhydride, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 1:0.8:0.06:30, stirred at 40°C and 600 r / min for 2.5 h, filtered, the filter residue was washed with deionized water for 5 times, and vacuum dried at 85°C for 6 h to obtain capped β-cyclodextrin; (2) Add polyetheramine at a rate of 40 drops / min into a saturated β-cyclodextrin aqueous solution with a mass 30 times that of the polyetheramine, stir at 600 r / min at 30°C for 2.5 h, let stand for 14 h, filter, wash the filter residue with deionized water for 5 times, and freeze-dry in vacuum for 12 h to obtain polypseudorotaxane; mix capped β-cyclodextrin, polypseudorotaxane, N-hydroxysuccinimide, carbodiimide, and N,N-dimethylformamide in a mass ratio of 1:6:0.06:0.06:14, stir at 600 r / min at room temperature, adjust the pH to 6.5 with 0.1 mol / L hydrochloric acid solution, continue the reaction for 2 h, filter, wash the filter residue with deionized water for 5 times, and vacuum dry at 85°C for 6 h to obtain polyrotaxane; (3) Mix polyrotaxane, allylphosphine dichloride and pyridine in a mass ratio of 1:4:50, stir at 600 r / min at 12°C for 5 h, add saturated copper sulfate solution 12 times the mass of pyridine, let stand for 14 h, filter, wash the filter residue with saturated copper sulfate solution and deionized water for 5 times, respectively, and vacuum dry at 85°C for 6 h to obtain a modified polyrotaxane; (4) Dimethoxymethylsilane and toluene were mixed in a mass ratio of 1:12, and deionized water with a mass of 5 times that of dimethoxymethylsilane was added dropwise at a rate of 4 ml / min. After the addition was completed, the mixture was stirred at 600 r / min for 35 min at 55°C, allowed to stand for 35 min, the organic phase was separated, and distilled under reduced pressure at 90°C to obtain an organosilicon monomer; polyethylene terephthalate, ethylene glycol, and zinc acetate were mixed in a mass ratio of 1:3.2:0.02, and distilled at 210°C under a nitrogen atmosphere. The mixture was stirred and refluxed at 800 r / min for 2 h, cooled to 90°C, filtered with deionized water for 5 times, the filtrate was cooled at 0°C and allowed to stand for 24 h, filtered, and the filter residue was dried at 80°C for 6 h to obtain the obtained product; the polyester prepolymer, silicone monomer, sodium hydroxide and toluene were mixed at a mass ratio of 1:0.4:0.04:12, stirred at 270°C and 600 r / min for 5 h under a nitrogen atmosphere, washed with deionized water for 5 times, and vacuum dried at 85°C for 6 h to obtain the modified polyester; (5) The modified polyester, modified polyrotaxane and azobisisobutyronitrile were mixed in a mass ratio of 1:0.4:0.06, and melt-extruded through a twin-screw extruder. The temperature of the first zone, the temperature of the second zone, the temperature of the third zone, and the temperature of the fourth zone were 275°C, and the temperature of the die head was 275°C. Under nitrogen protection, the mixture was allowed to stand at 140°C for 2 h. The mixture was spun on a spinning machine with a spinning specification of 150D / 48f, a spinning box temperature of 290°C, a spinneret aperture of 0.28 mm, a spinneret aperture aspect ratio of 2, and a winding rate of 3000 m / min. The mixture was cooled to room temperature through a side-blowing air tunnel to obtain fibers. The fibers were immersed in ammonia water at room temperature for 1 h, taken out, and dried at 105°C for 4 h to obtain fire-retardant fibers.

[0021] Comparative Example 1 A method for preparing a fire-retardant fiber comprises the following steps: (1) Dimethoxymethylsilane and toluene were mixed in a mass ratio of 1:10, and deionized water with a mass of 4 times that of dimethoxymethylsilane was added dropwise at a rate of 3 ml / min. After the addition was completed, the mixture was stirred at 500 r / min for 30 min at 50°C, allowed to stand for 30 min, the organic phase was separated, and distilled under reduced pressure at 85°C to obtain an organosilicon monomer; polyethylene terephthalate, ethylene glycol, and zinc acetate were mixed in a mass ratio of 1:3:0.015, and distilled under nitrogen atmosphere at 205°C for 7 00r / min stirring and reflux for 1.5h, cool to 85℃, filter with deionized water 4 times, cool the filtrate at 0℃ and let stand for 23h, filter, and dry the filter residue at 75℃ for 5h to obtain; polyester prepolymer, silicone monomer, sodium hydroxide and toluene are mixed in a mass ratio of 1:0.3:0.03:10, stirred at 255℃ and 500r / min for 4h under nitrogen atmosphere, washed with deionized water 4 times, and vacuum dried at 80℃ for 5h to obtain modified polyester; (2) The modified polyester, allyl phosphine dichloride and azobisisobutyronitrile were mixed in a mass ratio of 1:0.3:0.05, and melt-extruded through a twin-screw extruder. The temperature of the first zone, the temperature of the second zone, the temperature of the third zone and the temperature of the fourth zone were 270°C, and the temperature of the die head was 270°C. Under nitrogen protection, the mixture was allowed to stand at 140°C for 2 h. The mixture was spun on a spinning machine with a spinning specification of 150D / 48f, a spinning box temperature of 285°C, a spinneret aperture of 0.28 mm, a spinneret aperture aspect ratio of 2, a winding rate of 3000 m / min, and cooled to room temperature through a side-blowing air tunnel to obtain fibers. The fibers were immersed in ammonia water for 1 h at room temperature, taken out, and dried at 105°C for 4 h to obtain fire-retardant fibers.

[0022] Comparative Example 2 A method for preparing a fire-retardant fiber comprises the following steps: (1) β-cyclodextrin, allyl succinic anhydride, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 1:0.7:0.05:25, stirred at 35°C and 500 r / min for 2 h, filtered, the filter residue was washed with deionized water for 4 times, and vacuum dried at 80°C for 5 h to obtain capped β-cyclodextrin; (2) Add polyetheramine at a rate of 30 drops / min into a saturated β-cyclodextrin aqueous solution with a mass 27 times that of the polyetheramine, stir at 500 r / min at 25°C for 2 h, let stand for 12 h, filter, wash the filter residue with deionized water for 4 times, and freeze-dry in vacuum for 10 h to obtain polypseudorotaxane; mix capped β-cyclodextrin, polypseudorotaxane, N-hydroxysuccinimide, carbodiimide, and N,N-dimethylformamide in a mass ratio of 1:5:0.05:0.05:12, stir at 500 r / min at room temperature, adjust the pH to 6 with 0.1 mol / L hydrochloric acid solution, continue the reaction for 1.5 h, filter, wash the filter residue with deionized water for 4 times, and vacuum dry at 80°C for 5 h to obtain polyrotaxane; (3) Dimethoxymethylsilane and toluene were mixed in a mass ratio of 1:10, and deionized water with a mass of 4 times that of dimethoxymethylsilane was added dropwise at a rate of 3 ml / min. After the addition was completed, the mixture was stirred at 500 r / min for 30 min at 50°C, allowed to stand for 30 min, the organic phase was separated, and distilled under reduced pressure at 85°C to obtain an organosilicon monomer; polyethylene terephthalate, ethylene glycol, and zinc acetate were mixed in a mass ratio of 1:3:0.015, and distilled under a nitrogen atmosphere at 205°C for 7 00r / min stirring and reflux for 1.5h, cool to 85℃, filter with deionized water 4 times, cool the filtrate at 0℃ and let stand for 23h, filter, and dry the filter residue at 75℃ for 5h to obtain; polyester prepolymer, silicone monomer, sodium hydroxide and toluene are mixed in a mass ratio of 1:0.3:0.03:10, stirred at 255℃ and 500r / min for 4h under nitrogen atmosphere, washed with deionized water 4 times, and vacuum dried at 80℃ for 5h to obtain modified polyester; (4) The modified polyester, polyrotaxane and azobisisobutyronitrile were mixed in a mass ratio of 1:0.3:0.05, and melt-extruded through a twin-screw extruder. The temperature of the first zone, the temperature of the second zone, the temperature of the third zone, and the temperature of the fourth zone were 270°C, and the temperature of the die head was 270°C. Under nitrogen protection, the mixture was allowed to stand at 140°C for 2 h. The mixture was spun on a spinning machine with a spinning specification of 150D / 48f, a spinning box temperature of 285°C, a spinneret aperture of 0.28 mm, a spinneret aperture aspect ratio of 2, and a winding rate of 3000 m / min. The mixture was cooled to room temperature through a side-blowing air tunnel to obtain fibers. The fibers were immersed in ammonia water for 1 h at room temperature, taken out, and dried at 105°C for 4 h to obtain fire-retardant fibers.

[0023] Comparative Example 3 A method for preparing a fire-retardant fiber comprises the following steps: (1) β-cyclodextrin, allyl succinic anhydride, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 1:0.7:0.05:25, stirred at 35°C and 500 r / min for 2 h, filtered, the filter residue was washed with deionized water for 4 times, and vacuum dried at 80°C for 5 h to obtain capped β-cyclodextrin; (2) Add polyetheramine at a rate of 30 drops / min into a saturated β-cyclodextrin aqueous solution with a mass 27 times that of the polyetheramine, stir at 500 r / min at 25°C for 2 h, let stand for 12 h, filter, wash the filter residue with deionized water for 4 times, and freeze-dry in vacuum for 10 h to obtain polypseudorotaxane; mix capped β-cyclodextrin, polypseudorotaxane, N-hydroxysuccinimide, carbodiimide, and N,N-dimethylformamide in a mass ratio of 1:5:0.05:0.05:12, stir at 500 r / min at room temperature, adjust the pH to 6 with 0.1 mol / L hydrochloric acid solution, continue the reaction for 1.5 h, filter, wash the filter residue with deionized water for 4 times, and vacuum dry at 80°C for 5 h to obtain polyrotaxane; (3) Mix polyrotaxane, allylphosphine dichloride and pyridine in a mass ratio of 1:3:45, stir at 500 r / min for 4 h at 10°C, add saturated copper sulfate solution 10 times the mass of pyridine, let stand for 12 h, filter, wash the filter residue with saturated copper sulfate solution and deionized water for 4 times, respectively, and vacuum dry at 80°C for 5 h to obtain a modified polyrotaxane; (4) Polyethylene terephthalate, ethylene glycol and zinc acetate were mixed in a mass ratio of 1:3:0.015, stirred and refluxed at 205°C and 700 r / min for 1.5 h under a nitrogen atmosphere, cooled to 85°C, filtered with deionized water 4 times, the filtrate was cooled at 0°C and allowed to stand for 23 h, filtered, and the filter residue was dried at 75°C for 5 h to obtain polyester; polyester prepolymer, sodium hydroxide and toluene were mixed in a mass ratio of 1:0.03:10, stirred at 255°C and 500 r / min for 4 h under a nitrogen atmosphere, washed with deionized water 4 times, and vacuum dried at 80°C for 5 h to obtain polyester; (5) Polyester, modified polyrotaxane and azobisisobutyronitrile were mixed in a mass ratio of 1:0.3:0.05, and melt-extruded through a twin-screw extruder. The temperature of the first zone, the temperature of the second zone, the temperature of the third zone, and the temperature of the fourth zone were 270°C, and the temperature of the die head was 270°C. Under nitrogen protection, the mixture was allowed to stand at 140°C for 2 h. The mixture was spun on a spinning machine with a spinning specification of 150D / 48f, a spinning box temperature of 285°C, a spinneret aperture of 0.28 mm, a spinneret aperture aspect ratio of 2, and a winding rate of 3000 m / min. The mixture was cooled to room temperature through a side-blowing air tunnel to obtain fibers. The fibers were immersed in ammonia water at room temperature for 1 h, taken out, and dried at 105°C for 4 h to obtain fire-retardant fibers.

[0024] Test Example 1 Moisture absorption test Test method: The moisture regain test of the embodiment and the comparative example was carried out according to GB / T6503-2017 "Test method for moisture regain of chemical fibers". The results are shown in Table 1.

[0025] Table 1

[0026] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 1, it can be found that the fire-retardant fiber prepared in the present invention has good moisture absorption performance.

[0027] By comparison, the moisture regains of Examples 1 to 3 are significantly greater than that of Comparative Example 1, indicating that the polyetheramine penetrates the β-cyclodextrin cavity and is embedded into the β-cyclodextrin through the host-guest force to obtain the polypseudorotaxane, and the β-cyclodextrin modified with allyl succinic anhydride is terminated with the polypseudorotaxane through the amidation reaction of the amino group and the carboxyl group to obtain the polyrotaxane. The hydrophobic and hydrophilic properties of the β-cyclodextrin inside and outside and the hydrophilic properties of the polyetheramine make the polyrotaxane have good hydrophilic properties, thereby improving the hydrophilic and hygroscopic capacity of the fire-retardant fiber.

[0028] Test Example 2 Flame retardant performance test: Test method: The examples and comparative examples were melted at 180°C to prepare standard specimens according to GB / T 2406.2, and the limiting oxygen index of the standard specimens was tested. The results are shown in Table 2.

[0029] Table 2

[0030] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 2, it can be found that the fire-retardant fiber prepared by the present invention has good flame retardant properties.

[0031] By comparison, the limiting oxygen index of Examples 1 to 3 is greater than that of Comparative Example 2, indicating that the surface of the polyrotaxane contains phosphorus after being modified with allylphosphine dichloride, which can promote carbonization and isolate flames, and has a good flame retardant effect; the limiting oxygen index of Examples 1 to 3 is greater than that of Comparative Example 3, indicating that polyethylene terephthalate is hydrolyzed with ethylene glycol and then esterified with an organosilicon monomer, and a silicon-hydrogen structure is introduced into the polyester material, which can form a denser residual carbon structure and improve the flame retardant properties and mechanical properties of the fire-retardant fiber.

[0032] Test Example 3 Mechanical properties test: Test method: The tensile properties were tested according to the standard GB / T 14344-2008 Test method for tensile properties of chemical fiber filaments. The experimental conditions were set as follows: the pre-tension value was set to 5 cN, the clamping length was set to 250 mm, and the tensile rate was set to 250 mm / min. The results are shown in Table 3.

[0033] Table 3

[0034] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 3, it can be found that the fire-retardant fiber prepared by the present invention has good mechanical properties.

[0035] By comparison, the breaking strength of Examples 1 to 3 is significantly greater than that of Comparative Example 1, indicating that the long-chain structure of the polyetheramine and the hydroxyl group of β-cyclodextrin can form hydrogen bonds and ether bonds through molecular self-assembly, thereby improving the binding force with β-cyclodextrin and thus improving the mechanical properties of the fire-retardant fiber.

[0036] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fire-retardant fiber, characterized in that: The fireproof and flame-retardant fiber is prepared by reacting beta-cyclodextrin with allyl succinic anhydride to obtain blocked beta-cyclodextrin; reacting polyether amine with beta-cyclodextrin to obtain polypseudorotaxane; reacting polypseudorotaxane and blocked beta-cyclodextrin to obtain polyrotaxane; reacting polyrotaxane with allyl phosphine dichloride to obtain modified polyrotaxane; hydrolyzing and condensing dimethoxymethylsilane to obtain organosilicon monomer; reacting polyester prepolymer and organosilicon monomer to obtain modified polyester; and melt spinning the modified polyester and modified polyrotaxane.

2. A method for preparing a fire-retardant fiber, characterized in that: The method comprises the following preparation steps: (1) β-cyclodextrin, allyl succinic anhydride, p-toluenesulfonic acid and toluene are mixed in a mass ratio of 1: (0.6-0.8): (0.04-0.06): (20-30), stirred at 30-40°C and 400-600 r / min for 1.5-2.5 h, filtered, washed the filter residue with deionized water for 3-5 times, and vacuum dried at 75-85°C for 4-6 h to obtain capped β-cyclodextrin; (2) Adding polyetheramine at a rate of 20-40 drops / min into a saturated β-cyclodextrin aqueous solution with a mass of 25-30 times that of the polyetheramine, stirring at 400-600 r / min for 1.5-2.5 h at 20-30 °C, letting stand for 10-14 h, filtering, washing the filter residue with deionized water for 3-5 times, and freeze-drying in vacuum for 8-12 h to obtain polypseudorotaxane; adding capped β-cyclodextrin, polypseudorotaxane, N-hydroxysuccinimide, carbodiimide, N , N-dimethylformamide is mixed in a mass ratio of 1: (4-6): (0.04-0.06): (0.04-0.06): (10-14), stirred at 400-600 r / min at room temperature, adjusted to pH 5.5-6.5 with 0.1 mol / L hydrochloric acid solution, continued to react for 1-2 hours, filtered, washed the residue with deionized water for 3-5 times, and vacuum dried at 75-85°C for 4-6 hours to obtain a polyrotaxane; (3) Mix polyrotaxane, allylphosphine dichloride and pyridine in a mass ratio of 1: (2-4): (40-50), stir at 400-600 r / min for 3-5 h at 8-12 °C, add saturated copper sulfate solution 8-12 times the mass of pyridine, let stand for 10-14 h, filter, wash the residue with saturated copper sulfate solution and deionized water for 3-5 times, respectively, and vacuum dry at 75-85 °C for 4-6 h to obtain a modified polyrotaxane; (4) Dimethoxymethylsilane and toluene are mixed in a mass ratio of 1: (8-12), and deionized water 3-5 times the mass of dimethoxymethylsilane is added dropwise at a rate of 2-4 ml / min. After the addition is completed, the mixture is stirred at 400-600 r / min for 25-35 min at 45-55 °C, allowed to stand for 25-35 min, the organic phase is separated, and distilled under reduced pressure at 80-90 °C to obtain an organosilicon monomer; polyester prepolymer, organosilicon monomer, sodium hydroxide and toluene are mixed in a mass ratio of 1: (0.2-0.4): (0.02-0.04): (8-12), stirred at 240-270 °C and 400-600 r / min for 3-5 h under a nitrogen atmosphere, washed with deionized water for 3-5 times, and vacuum dried at 75-85 °C for 4-6 h to obtain a modified polyester; (5) The modified polyester, modified polyrotaxane and azobisisobutyronitrile are mixed in a mass ratio of 1: (0.2-0.4): (0.04-0.06), melt-extruded through a twin-screw extruder, allowed to stand at 140-160°C for 2-4 hours under nitrogen protection, spun, and cooled to room temperature through a side-blown air tunnel to obtain fibers. The fibers are immersed in ammonia water at room temperature for 1-2 hours, taken out, and dried at 105-115°C for 4-6 hours to obtain fire-retardant fibers.

3. The method for preparing a fire-retardant fiber according to claim 2, characterized in that: The polyetheramine in step (2) is D230 type polyetheramine.

4. The method for preparing a fire-retardant fiber according to claim 2, characterized in that: The method for preparing the saturated β-cyclodextrin aqueous solution in step (2) is as follows: β-cyclodextrin and deionized water are mixed in a mass ratio of 1:10, stirred at 200 r / min for 2 h at 60° C., and the upper layer of liquid is obtained.

5. The method for preparing a fire-retardant fiber according to claim 2, characterized in that: The polyester prepolymer preparation method of step (4) is as follows: polyethylene terephthalate, ethylene glycol and zinc acetate are mixed in a mass ratio of 1: (2.8-3.2): (0.01-0.02), stirred and refluxed at 200-210° C. and 600-800 r / min for 1-2 h under a nitrogen atmosphere, cooled to 80-90° C., filtered with deionized water for 3-5 times, cooled the filtrate at 0° C. and allowed to stand for 22-24 h, filtered, and dried the filter residue at 70-80° C. for 4-6 h to obtain the product.

6. The method for preparing a fire-retardant fiber according to claim 2, characterized in that: The process parameters of the twin-screw extruder in step (5) are: zone 1 temperature 265-275°C, zone 2 temperature 265-275°C, zone 3 temperature 270-280°C, zone 4 temperature 270-280°C, and die head temperature 265-275°C.

7. The method for preparing a fire-retardant fiber according to claim 2, characterized in that: The spinning process parameters of step (5) are: spinning specification 150D / 48f, spinning box temperature 280-290°C, spinneret aperture 0.28mm, spinneret aperture aspect ratio 2, and winding speed 3000m / min.

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