Preparation method of acid and alkali resistant regenerated yarn

Abstract

The present invention discloses a preparation method of acid and alkali resistant regenerated yarn, which relates to the technical field of textile fibers. In the present invention, sodium aminosulfonate is used to dissolve waste cotton fibers under shear action, and then phosphoric acid is added. The shear force makes the cellulose dissociate evenly to achieve the regeneration effect. Then, silica sol and silicon carbide whiskers are used to carry out blending modification with regenerated cellulose, and secondary drawing is carried out during the spinning process, so that the fibers shrink under the condition of internal acting force to form a relatively dense structure, thereby enhancing the acid and alkali resistance and mechanical properties of the fibers. Finally, sodium citrate and titanium ions form a complex, so as to form a metal titanium coating with good bonding force and density on the rough surface of the fibers, further improving the acid and alkali resistance and mechanical properties of the fibers.

Description

Technical Field

[0001] The present invention relates to the technical field of textile fibers, and particularly to a preparation method of acid and alkali resistant regenerated yarn. Background Art

[0002] As a necessity of life, the demand for textiles has gradually increased with the increase in the population. In the past two decades, the global fiber production has nearly tripled, increasing from 58 million tons in 2000 to 109 million tons in 2020, and it is expected that the global fiber production will increase to 146 million tons by 2030. Under the influence of the fast fashion trend, the replacement speed of textiles has accelerated, and the service life of clothes has decreased. Most clothes are discarded after being worn a few times, resulting in a waste of resources. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method of acid and alkali resistant regenerated yarn to solve the problems existing in the prior art.

[0004] To solve the above technical problems, the present invention provides the following technical solution: A preparation method of acid and alkali resistant regenerated yarn, comprising the following preparation steps:

[0005] (1) Mix sodium hydroxide, sodium aminosulfonate and deionized water, stir at 100 - 200 rpm for 20 - 40 min, cool down to -10 - -15 °C, add cotton fibers, and perform shearing. Wait for the solution to warm up to room temperature, add 90 wt% phosphoric acid aqueous solution, continue shearing for 1 - 3 h, then centrifuge at 9000 - 15000 rpm for 8 - 16 min. Then continuously add deionized water and stir until white flocculates appear. Let it stand for 1 - 3 h, pour off the supernatant, centrifuge the remaining part at 5000 - 8000 rpm for 8 - 16 min, filter, take the solid, and wash it until the pH of the washing solution is 7 - 8, dry at 30 - 60 °C for 20 - 30 h to obtain regenerated cellulose;

[0006] (2) Mix regenerated cellulose, ethanol and deionized water, place it in a water bath at 50 °C, stir at 120 rpm for 1 - 3 h, add silica sol and silicon carbide whiskers, continue stirring for 2 - 5 h, add octyl polysiloxane, stir for another 3 h, adjust the pH of the solution to 10 with sodium hydroxide, then perform wet spinning into a coagulation bath of 50 wt% ethanol aqueous solution, coagulate for 1 - 3 h, and perform stretching during the coagulation process, with a stretching ratio of 1.3 - 1.8. Then fish it out, rinse it with deionized water 5 - 10 times, perform the second stretching, with a stretching ratio of 1.1 - 1.4, dry at 40 - 60 °C for 3 - 5 h to obtain regenerated yarn;

[0007] (3) Immerse the recycled yarn in the sensitizing solution, and carry out sensitization treatment at 30-40 °C for 10-18 min. Take it out and wash it 3-8 times with deionized water. Then immerse it in the activation solution, and carry out activation treatment at 30-40 °C for 8-12 min. Take it out and wash it 3-8 times with deionized water to obtain the pretreated recycled yarn. Mix titanium sulfate, sodium hypophosphite, sodium citrate, ammonium chloride and deionized water according to the mass ratio of 4.5:2:4.5:5:300-500, adjust the pH of the solution to 8-9 with ammonia water, heat up to 90 °C, add 1-10 times of the mass of titanium sulfate of the pretreated recycled yarn for electroless plating, and stir it every 10 min. Then take it out and wash it 3-8 times with deionized water, and dry it at 40-60 °C for 3-5 h to obtain the acid and alkali resistant recycled yarn.

[0008] Further, the preparation method of the cotton fiber in step (1): Cut the waste cotton fabric into pieces of 1 cm×1 cm, break it into fibrous shape at 200-500 rpm, and dry it at 45-75 °C for 15-30 h to obtain it.

[0009] Further, the shear rate in step (1) is 100-500 rpm.

[0010] Further, the mass ratio of sodium hydroxide, sodium aminosulfonate, deionized water, cotton fiber and 90 wt% phosphoric acid aqueous solution in step (1) is 3-8:0.1-0.5:150:5-10:80-100.

[0011] Further, the preparation method of the silica sol in step (2): Mix nano-silica and ethanol according to the mass ratio of 5:80-150, stir at 500 rpm for 20-50 min, and adjust the pH of the solution to 9.5-11 with ammonia water. Heat up to 40 °C, add vinyltrimethoxysilane 1.5-4 times the mass of nano-silica, and ultrasonicate at 21 kHz for 100-200 min to obtain it.

[0012] Further, the process parameters of the wet spinning in step (2): The needle aperture is 0.2-0.6 mm, and the extrusion speed is 0.04-0.1 mL / min.

[0013] Further, the mass ratio of regenerated cellulose, ethanol, deionized water, silica sol, silicon carbonate whisker and octyl polysiloxane in step (2) is 5-10:70:50:100-200:0.5-2:0.1.

[0014] Further, the preparation method of the sensitizing solution in step (3): Mix stannous chloride, deionized water and 90 wt% hydrochloric acid aqueous solution evenly according to the mass ratio of 0.5:50:2.5 to obtain it.

[0015] Further, the preparation method of the activation solution described in step (3) is as follows: Palladium chloride, ethanol, and deionized water are mixed evenly according to the mass ratio of 0.25:500:500 to obtain the activation solution.

[0016] Further, the process parameters of the electroless plating described in step (3) are as follows: The accelerating voltage is 5 kV, the accelerating current is 10 μA, the working distance is 7 mm, and the time is 30 - 70 min.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0018] The regenerated yarn of the present invention is prepared by sequentially dissolving waste cotton fibers with sodium aminosulfonate and phosphoric acid, then blending and spinning with silica sol and silicon carbide whiskers, and plating a metal layer on its surface to achieve the effects of acid and alkali resistance and high strength.

[0019] First, under the shearing action, sodium aminosulfonate is used to dissolve waste cotton fibers. In a low-temperature environment, first, sodium hydroxide is used to swell cellulose, and through mechanical shearing force, sodium aminosulfonate is assisted to penetrate between the cellulose molecular chains. Then, the hydrogen bond structure of cellulose molecules is destroyed by the hydrogen bond donor and hydrogen bond acceptor in its structure, promoting the dissolution of highly polymerized cellulose molecules with low accessibility in cotton fiber molecules. Since the dissolution of cotton fiber is an exothermic process, when the solution temperature reaches room temperature, phosphoric acid is added. Under the continuous attack of the shearing force and the protons ionized by phosphoric acid, cellulose finally presents a positively charged structure. Coupled with the destruction of intermolecular hydrogen bonds and the electrostatic repulsion of cations, cellulose dissociation is made uniform, indirectly enhancing the mechanical properties of the silk thread and achieving the regeneration effect.

[0020] Secondly, silica sol and silicon carbide whiskers are used for blending and modification with regenerated cellulose. A large number of hydroxyl groups on the cellulose surface react with the hydroxyl groups of the sol, causing the molecular chains of silica sol and cellulose to entangle with each other to form a uniform network structure. Among them, silicon carbide whiskers are adsorbed by negatively charged silica gel particles and form a coating layer on their surface, increasing the electrostatic repulsion potential energy between substances, thus effectively preventing the agglomeration between whiskers, making the matrix structure more stable, enhancing the mechanical properties of the matrix, and by reducing the hydrophilic groups in cellulose, enhancing the hydrophobicity of the matrix and forming a rough structure on the fiber surface, so as to prevent the persecution of acid or alkali solutions and achieve the effect of acid and alkali resistance. Then, during the spinning process, secondary drawing is carried out. The fiber shrinks under the condition of internal acting forces to form a relatively dense structure. During the drawing process, cellulose stretches under the action of tension, making the silicon carbide whiskers form an ordered structure parallel to the fiber direction and increasing the fiber orientation degree, which is beneficial to improving the mechanical properties of the fiber. Finally, a complex is formed by sodium citrate and titanium ions, so as to form a metal titanium coating with good bonding force and density on the rough surface of the fiber, further improving the acid and alkali resistance and mechanical properties of the fiber. Detailed implementation mode

[0021] The following will combine 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 a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0022] In order to more clearly illustrate the method provided by the present invention, the following embodiments are used for detailed description. The test methods for each index of the acid and alkali resistant regenerated yarn produced in the following embodiments are as follows:

[0023] Acid and alkali resistance: Take the same size of the embodiment and the comparative example and refer to GB / T20102 to respectively test the acid resistance strength retention rate and the alkali resistance strength retention rate. The acid solution is a 10wt% sulfuric acid aqueous solution, the alkali solution is a 5wt% sodium hydroxide aqueous solution, the temperature is 30°C for both, and the time is 96h for both.

[0024] Mechanical properties: Take the same size of the embodiment and the comparative example and detect their strength according to GB / T14337.

[0025] Example 1; (1) Cut the waste cotton fabric into pieces of 1 cm × 1 cm, break it into fibrous form at 200 rpm, dry it at 45°C for 15 h to obtain cotton fibers; mix sodium hydroxide, sodium aminosulfonate, and deionized water, stir at 100 rpm for 20 min, cool down to -10°C, add cotton fibers, and perform shearing at a shearing rate of 100 rpm. When the solution warms up to room temperature, add 90wt% phosphoric acid aqueous solution and continue shearing for 1 h. Then centrifuge at 9000 rpm for 8 min. Then continuously add deionized water and stir until white flocs appear. Let it stand for 1 h, pour off the supernatant, centrifuge the remaining part at 5000 rpm for 8 min, filter, take the solid, and wash it until the pH of the washing solution is 7, and dry it at 30°C for 20 h to obtain regenerated cellulose; the mass ratio of sodium hydroxide, sodium aminosulfonate, deionized water, cotton fibers, and 90wt% phosphoric acid aqueous solution is 3:0.1:150:5:80;

[0026] (2) Mix nano-silica and ethanol at a mass ratio of 5:80, stir at 500 rpm for 20 min, adjust the solution pH to 9.5 with ammonia water, heat up to 40 °C, add vinyltrimethoxysilane which is 1.5 times the mass of nano-silica, and ultrasonicate at 21 kHz for 100 min to obtain silica sol; Mix regenerated cellulose, ethanol, and deionized water, place them in a water bath at 50 °C, stir at 120 rpm for 1 h, add silica sol and silicon carbide whiskers, continue stirring for 2 h, add octyl polysiloxane, stir for another 3 h, adjust the solution pH to 10 with sodium hydroxide, and then perform wet spinning. The process parameters are: the needle aperture is 0.2 mm, the extrusion speed is 0.04 mL / min, into a 50 wt% ethanol aqueous solution coagulation bath, coagulate for 1 h, and perform stretching during the coagulation process, with a stretching ratio of 1.3. Then take it out, wash it 5 times with deionized water, perform a second stretching, with a stretching ratio of 1.1, and dry at 40 °C for 3 h to obtain regenerated yarn; The mass ratio of the regenerated cellulose, ethanol, deionized water, silica sol, silicon carbide whiskers, and octyl polysiloxane is 5:70:50:100:0.5:0.1;

[0027] (3) Mix stannous chloride, deionized water, and 90 wt% hydrochloric acid aqueous solution evenly at a mass ratio of 0.5:50:2.5 to obtain a sensitizing solution; Mix palladium chloride, ethanol, and deionized water evenly at a mass ratio of 0.25:500:500 to obtain an activating solution; Immerse the regenerated yarn in the sensitizing solution, perform sensitization treatment at 30 °C for 10 min, take it out, wash it 3 times with deionized water, and then immerse it in the activating solution, perform activation treatment at 30 °C for 8 min, take it out, wash it 3 times with deionized water to obtain a pretreated regenerated yarn; Mix titanium orthosulfate, sodium hypophosphite, sodium citrate, ammonium chloride, and deionized water at a mass ratio of 4.5:2:4.5:5:300, adjust the solution pH to 8 with ammonia water, heat up to 90 °C, add the pretreated regenerated yarn which is 1 times the mass of titanium orthosulfate for electroless plating. The process parameters are: the accelerating voltage is 5 kV, the accelerating current is 10 μA, the working distance is 7 mm, the time is 30 min, and stir once every 10 min. Then take it out and wash it 3 times with deionized water, and dry at 40 °C for 3 h to obtain acid- and alkali-resistant regenerated yarn.

[0028] Example 2; (1) Cut waste cotton fabrics into pieces of 1 cm × 1 cm, break them into fibrous form at 350 rpm, dry at 60 °C for 23 h to obtain cotton fibers; mix sodium hydroxide, sodium aminosulfonate and deionized water, stir at 150 rpm for 30 min, cool down to -13 °C, add cotton fibers and perform shearing at a shearing rate of 300 rpm. When the solution warms up to room temperature, add 90 wt% phosphoric acid aqueous solution, continue shearing for 2 h, then centrifuge at 11000 rpm for 12 min. Then continuously add deionized water and stir until white flocculates appear, let stand for 2 h, pour off the supernatant, centrifuge the remaining part at 6500 rpm for 12 min, filter, take the solid, wash until the pH of the washing liquid is 7.5, and dry at 45 °C for 25 h to obtain regenerated cellulose; the mass ratio of sodium hydroxide, sodium aminosulfonate, deionized water, cotton fibers, and 90 wt% phosphoric acid aqueous solution is 6:0.3:150:7.5:90;

[0029] (2) Mix nano-silica and ethanol at a mass ratio of 5:110, stir at 500 rpm for 35 min, and adjust the pH of the solution to 10 with ammonia water. Heat up to 40 °C, add vinyltrimethoxysilane which is 3 times the mass of nano-silica, and ultrasonicate at 21 kHz for 150 min to obtain silica sol; mix regenerated cellulose, ethanol and deionized water, place in a water bath at 50 °C, stir at 120 rpm for 2 h, add silica sol and silicon carbide whiskers, continue stirring for 3.5 h, add octyl polysiloxane, stir for another 3 h, adjust the pH of the solution to 10 with sodium hydroxide, and then perform wet spinning. The process parameters are: the needle aperture is 0.4 mm, the extrusion speed is 0.07 mL / min, into a 50 wt% ethanol aqueous solution coagulation bath, coagulate for 2 h, and perform stretching during the coagulation process with a stretching ratio of 1.5. Then fish out, rinse with deionized water 8 times, perform the second stretching with a stretching ratio of 1.2, and dry at 50 °C for 4 h to obtain regenerated yarn; the mass ratio of regenerated cellulose, ethanol, deionized water, silica sol, silicon carbide whiskers, and octyl polysiloxane is 8:70:50:150:1.25:0.1;

[0030] (3) Mix stannous chloride, deionized water, and 90 wt% hydrochloric acid aqueous solution evenly according to a mass ratio of 0.5:50:2.5 to obtain a sensitizing solution; mix palladium chloride, ethanol, and deionized water evenly according to a mass ratio of 0.25:500:500 to obtain an activating solution; immerse the regenerated yarn in the sensitizing solution, and perform sensitization treatment at 35 °C for 14 min, then take it out and wash it 5 times with deionized water, then immerse it in the activating solution, and perform activation treatment at 35 °C for 10 min, take it out and wash it 5 times with deionized water to obtain a pretreated regenerated yarn; mix titanium orthosulfate, sodium hypophosphite, sodium citrate, ammonium chloride, and deionized water according to a mass ratio of 4.5:2:4.5:5:400, adjust the pH of the solution to 8.5 with ammonia water, heat up to 90 °C, add 6 times the mass of the pretreated regenerated yarn of titanium orthosulfate, and perform electroless plating. The process parameters are: acceleration voltage is 5 kV, acceleration current is 10 μA, working distance is 7 mm, time is 50 min, and stir once every 10 min, then take it out and wash it 5 times with deionized water, and dry it at 50 °C for 4 h to obtain an acid- and alkali-resistant regenerated yarn.

[0031] Example 3; (1) Cut the waste cotton fabric into pieces of 1 cm × 1 cm, break it into fibrous shape at 500 rpm, and dry it at 75 °C for 30 h to obtain cotton fibers; mix sodium hydroxide, sodium aminosulfonate, and deionized water, stir at 200 rpm for 40 min, cool down to -15 °C, add cotton fibers, and perform shearing at a shearing rate of 500 rpm. Wait for the solution to warm up to room temperature, add 90 wt% phosphoric acid aqueous solution, and continue shearing for 3 h, then centrifuge at 15000 rpm for 16 min. Then continuously add deionized water and stir until white flocs appear, let it stand for 3 h, pour off the supernatant, centrifuge the remaining part at 8000 rpm for 16 min, filter, take the solid, and wash it until the pH of the washing solution is 8, and dry it at 60 °C for 30 h to obtain regenerated cellulose; the mass ratio of sodium hydroxide, sodium aminosulfonate, deionized water, cotton fibers, and 90 wt% phosphoric acid aqueous solution is 8:0.5:150:10:100;

[0032] (2) Mix nano-silica and ethanol at a mass ratio of 5:150, stir at 500 rpm for 50 min, adjust the solution pH to 11 with ammonia water, heat up to 40 °C, add vinyltrimethoxysilane which is 4 times the mass of nano-silica, and ultrasonicate at 21 kHz for 200 min to obtain silica sol; Mix regenerated cellulose, ethanol, and deionized water, place it in a water bath at 50 °C, stir at 120 rpm for 3 h, add silica sol and silicon carbide whiskers, continue to stir for 5 h, add octyl polysiloxane, stir for another 3 h, adjust the solution pH to 10 with sodium hydroxide, and then perform wet spinning. The process parameters are: the needle aperture is 0.6 mm, the extrusion speed is 0.1 mL / min, into a 50 wt% ethanol aqueous solution coagulation bath, coagulate for 3 h, and perform stretching during the coagulation process. The stretching ratio is 1.8. Then take it out, wash it 10 times with deionized water, perform the second stretching, the stretching ratio is 1.4, and dry it at 60 °C for 5 h to obtain regenerated yarn; The mass ratio of the regenerated cellulose, ethanol, deionized water, silica sol, silicon carbide whiskers, and octyl polysiloxane is 10:70:50:200:2:0.1;

[0033] (3) Mix stannous chloride, deionized water, and 90 wt% hydrochloric acid aqueous solution at a mass ratio of 0.5:50:2.5 evenly to obtain a sensitizing solution; Mix palladium chloride, ethanol, and deionized water at a mass ratio of 0.25:500:500 evenly to obtain an activating solution; Immerse the regenerated yarn in the sensitizing solution, perform sensitization treatment at 40 °C for 18 min, take it out, wash it 8 times with deionized water, then immerse it in the activating solution, perform activation treatment at 40 °C for 12 min, take it out, wash it 8 times with deionized water to obtain a pretreated regenerated yarn; Mix titanium orthosulfate, sodium hypophosphite, sodium citrate, ammonium chloride, and deionized water at a mass ratio of 4.5:2:4.5:5:500, adjust the solution pH to 9 with ammonia water, heat up to 90 °C, add 10 times the mass of the pretreated regenerated yarn of titanium orthosulfate, and perform electroless plating. The process parameters are: the accelerating voltage is 5 kV, the accelerating current is 10 μA, the working distance is 7 mm, the time is 70 min, and stir once every 10 min. Then take it out and wash it 8 times with deionized water, and dry it at 60 °C for 5 h to obtain acid and alkali resistant regenerated yarn.

[0034] Comparative Example 1; The difference between Comparative Example 1 and Example 2 lies in step (2). Step (2) is changed to: Mix regenerated cellulose, ethanol, and deionized water, place it in a water bath at 50°C, stir at 120 rpm for 2 h, add silicon carbide whiskers, continue stirring for 3.5 h, add octyl polysiloxane, stir for another 3 h, adjust the pH of the solution to 10 with sodium hydroxide, and then perform wet spinning. The process parameters are: the needle aperture is 0.4 mm, the extrusion speed is 0.07 mL / min, into a 50 wt% ethanol aqueous solution coagulation bath, coagulate for 2 h, and perform stretching during the coagulation process, with a draw ratio of 1.5. Then take it out, rinse it 8 times with deionized water, perform a second stretching, with a draw ratio of 1.2, and dry it at 50°C for 4 h to obtain regenerated yarn; The mass ratio of the regenerated cellulose, ethanol, deionized water, silicon carbide whiskers, and octyl polysiloxane is 8:70:50:1.25:0.1; The remaining steps are the same as in Example 2.

[0035] Comparative Example 2; The difference between Comparative Example 2 and Example 2 lies in step (2). Step (2) is changed to: Mix nano-silica and ethanol in a mass ratio of 5:110, stir at 500 rpm for 35 min, and adjust the pH of the solution to 10 with ammonia water, heat up to 40°C, add vinyltrimethoxysilane which is 3 times the mass of the nano-silica, and perform ultrasonic treatment at 21 kHz for 150 min to obtain silica sol; Mix regenerated cellulose, ethanol, and deionized water, place it in a water bath at 50°C, stir at 120 rpm for 2 h, add the silica sol, continue stirring for 3.5 h, add octyl polysiloxane, stir for another 3 h, adjust the pH of the solution to 10 with sodium hydroxide, and then perform wet spinning. The process parameters are: the needle aperture is 0.4 mm, the extrusion speed is 0.07 mL / min, into a 50 wt% ethanol aqueous solution coagulation bath, coagulate for 2 h, and perform stretching during the coagulation process, with a draw ratio of 1.5. Then take it out, rinse it 8 times with deionized water, perform a second stretching, with a draw ratio of 1.2, and dry it at 50°C for 4 h to obtain regenerated yarn; The mass ratio of the regenerated cellulose, ethanol, deionized water, silica sol, and octyl polysiloxane is 8:70:50:150:0.1; The remaining steps are the same as in Example 2.

[0036] Comparative Example 3; The difference between Comparative Example 3 and Example 2 lies in step (2). Step (2) is changed to: Mix nano-silica and ethanol at a mass ratio of 5:110, stir at 500 rpm for 35 min, and adjust the pH of the solution to 10 with ammonia water. Heat to 40 °C, add vinyltrimethoxysilane which is 3 times the mass of the nano-silica, and ultrasonicate at 21 kHz for 150 min to obtain silica sol; Mix regenerated cellulose, ethanol, and deionized water, place in a water bath at 50 °C, stir at 120 rpm for 2 h, add the silica sol and silicon carbide whiskers, continue stirring for 3.5 h, add octyl polysiloxane, stir for another 3 h, adjust the pH of the solution to 10 with sodium hydroxide, and then perform wet spinning. The process parameters are: the needle aperture is 0.4 mm, the extrusion speed is 0.07 mL / min, into a 50 wt% ethanol aqueous solution coagulation bath, coagulate for 2 h, take out, rinse 8 times with deionized water, and dry at 50 °C for 4 h to obtain regenerated yarn; The mass ratio of the regenerated cellulose, ethanol, deionized water, silica sol, silicon carbide whiskers, and octyl polysiloxane is 8:70:50:150:1.25:0.1; The remaining steps are the same as those in Example 2.

[0037] Comparative Example 4; The difference between Comparative Example 4 and Example 2 is that step (3) is absent; The remaining steps are the same as those in Example 2.

[0038] Effect Example

[0039] The performance analysis results of the acid- and alkali-resistant regenerated yarns using Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention are given in Table 1 below.

[0040] Table 1

[0041]

[0042] From the comparison of the experimental results between the examples and the comparative examples in Table 1, it can be found that in the present invention, silica sol, silicon carbide whiskers and regenerated cellulose are blended and modified, so that the molecular chains of silica sol and cellulose are intertwined to form a uniform network structure. Among them, the silicon carbide whiskers are adsorbed by the negatively charged silica gel particles and form a coating layer on their surface, increasing the electrostatic repulsive potential energy between substances, thereby effectively preventing the agglomeration between whiskers, making the matrix structure more stable, enhancing the mechanical properties of the matrix, and by reducing the hydrophilic groups in cellulose, the hydrophobicity of the matrix is enhanced, and a rough structure is formed on the fiber surface, so as to prevent the persecution of acid or alkali solution. Then, during the spinning process, secondary drawing is carried out, and the fiber shrinks under the condition of internal acting force to form a relatively dense structure, and the silicon carbide whiskers form an ordered structure in the direction parallel to the fiber, which is beneficial to improving the mechanical properties of the fiber. Finally, a complex is formed by sodium citrate and titanium ions, so as to form a metal titanium coating with good bonding force and density on the rough surface of the fiber, further improving the acid and alkali resistance and mechanical properties of the fiber.

[0043] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed claim.

Claims

1. A method for preparing acid- and alkali-resistant regenerated yarn, characterized in that: The method comprises the following preparation steps: (1) Sodium hydroxide, sodium aminosulfonate and deionized water are mixed, stirred at 100-200 rpm for 20-40 min, cooled to -10--15°C, cotton fibers are added, and shearing is performed. After the solution is heated to room temperature, a 90 wt% phosphoric acid aqueous solution is added, and shearing is continued for 1-3 h, and then centrifuged at 9000-15000 rpm for 8-16 min, and then deionized water is continuously added and stirred until white flocs appear. The mixture is allowed to stand for 1-3 h, the supernatant is removed, and the remaining portion is centrifuged at 5000-8000 rpm for 8-16 min, filtered, and the solid is taken out and washed until the pH of the washing solution is 7-8, and dried at 30-60°C for 20-30 h to obtain regenerated cellulose; (2) Regenerated cellulose, ethanol and deionized water were mixed and placed in a water bath at 50°C, stirred at 120 rpm for 1-3 h, silica sol and silicon carbonate whiskers were added, and stirring was continued for 2-5 h, octyl polysiloxane was added, and stirring was continued for 3 h, and the pH of the solution was adjusted to 10 with sodium hydroxide, and then wet-spun into a 50 wt% ethanol aqueous solution coagulation bath, coagulated for 1-3 h, and stretched during the coagulation process, with a stretch ratio of 1.3-1.8, then taken out, rinsed with deionized water for 5-10 times, and stretched for the second time, with a stretch ratio of 1.1-1.4, and dried at 40-60°C for 3-5 h to obtain regenerated yarn; (3) Immerse the regenerated yarn in a sensitizing solution at 30-40°C for sensitization treatment for 10-18 minutes, remove it, wash it with deionized water for 3-8 times, and then immerse it in an activation solution at 30-40°C for activation treatment for 8-12 minutes, remove it, wash it with deionized water for 3-8 times, and obtain pretreated regenerated yarn; mix titanium sulfate, sodium hypophosphite, sodium citrate, ammonium chloride, and deionized water in a mass ratio of 4.5:2:4.5:5:300-500, adjust the solution pH to 8-9 with ammonia water, heat it to 90°C, add 1-10 times the mass of titanium sulfate to the pretreated regenerated yarn, perform chemical plating, stir it every 10 minutes, then remove it, wash it with deionized water for 3-8 times, and dry it at 40-60°C for 3-5 hours to obtain acid and alkali resistant regenerated yarn.

2. The method for preparing an acid- and alkali-resistant regenerated yarn according to claim 1, characterized in that: The preparation method of the cotton fiber in step (1) is as follows: the waste cotton fabric is cut into 1 cm×1 cm size, broken into fibers at 200-500 rpm, and dried at 45-75° C. for 15-30 hours.

3. The method for preparing an acid- and alkali-resistant regenerated yarn according to claim 1, characterized in that: The shear rate in step (1) is 100-500 rpm.

4. The method for preparing an acid- and alkali-resistant regenerated yarn according to claim 1, characterized in that: The mass ratio of the sodium hydroxide, sodium sulfamate, deionized water, cotton fiber and 90wt% phosphoric acid aqueous solution in step (1) is 3~8:0.1~0.5:150:5~10:80~100.

5. The method for preparing acid- and alkali-resistant regenerated yarn according to claim 1, characterized in that: The preparation method of the silica sol in step (2) is as follows: nano-silica and ethanol are mixed in a mass ratio of 5:80-150, stirred at 500 rpm for 20-50 min, and the solution pH is adjusted to 9.5-11 with aqueous ammonia, heated to 40° C., and vinyltrimethoxysilane in an amount of 1.5-4 times the mass of the nano-silica is added, and ultrasonicated at 21 kHz for 100-200 min to obtain the obtained solution.

6. The method for preparing acid- and alkali-resistant regenerated yarn according to claim 1, characterized in that: The process parameters of the wet spinning in step (2) are: needle aperture of 0.2-0.6 mm, and extrusion speed of 0.04-0.1 mL / min.

7. The method for preparing acid- and alkali-resistant regenerated yarn according to claim 1, characterized in that: The mass ratio of the regenerated cellulose, ethanol, deionized water, silica sol, silicon carbonate whisker and octyl polysiloxane in step (2) is 5-10:70:50:100-200:0.5-2:0.

1.

8. The method for preparing acid- and alkali-resistant regenerated yarn according to claim 1, characterized in that: The preparation method of the sensitizing solution in step (3) is as follows: stannous chloride, deionized water, and 90 wt% hydrochloric acid aqueous solution are uniformly mixed in a mass ratio of 0.5:50:2.5 to obtain the sensitizing solution.

9. The method for preparing acid- and alkali-resistant regenerated yarn according to claim 1, characterized in that: The preparation method of the activation solution in step (3) is as follows: palladium chloride, ethanol and deionized water are uniformly mixed in a mass ratio of 0.25:500:500 to obtain the activation solution.

10. The method for preparing acid- and alkali-resistant regenerated yarn according to claim 1, characterized in that: The process parameters of the chemical plating in step (3) are as follows: acceleration voltage of 5 kV, acceleration current of 10 μA, working distance of 7 mm, and time of 30 to 70 min.

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