Degradable antibacterial fiber and preparation method thereof

Abstract

The invention discloses a degradable antibacterial fiber and a preparation method thereof, and relates to the technical field of fibers. When the degradable antibacterial fiber is prepared, 2-methyl benzoic acid firstly reacts with methanol, then reacts with hydrazine hydrate, and finally reacts with S-iso-methyl thiourea methyl sulfate to prepare the antibacterial agent. The preparation method comprises the following steps: carrying out dehydration condensation on 1, 4-butanediol, 1, 5-glutaric acid, a modified flame retardant and 1, 2, 3, 4-cyclobutanetetracarboxylic dianhydride to prepare modified polyester; the preparation method comprises the following steps: reacting nano titanium dioxide with hydrolyzed 3-aminopropyltrimethoxysilane, and then reacting with thiodipropionic acid to obtain the modified nano titanium dioxide. And mixing the modified polyester with the modified nano titanium dioxide, and carrying out melt spinning to obtain the modified polyester fiber. And treating the modified polyester fiber with a post-treatment solution prepared from the antibacterial agent to obtain the degradable antibacterial fiber. The degradable antibacterial fiber prepared by the preparation method disclosed by the invention has excellent degradability and antibacterial property.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fibers, in particular to a degradable antibacterial fiber and a preparation method thereof. BACKGROUND

[0002] Fibers are basic materials in the fields of textiles, clothing, medical treatment and filtration, and the demand for fibers is increasing. However, traditional synthetic fibers, especially polyester fibers, are derived from non-renewable petroleum resources and are difficult to degrade in the natural environment, causing serious "white pollution" problems. Although biodegradable polyesters such as poly(1,5-pentylene succinate) have been developed and applied, they usually have defects such as insufficient mechanical properties and single function, which limit their application in high-value-added fields.

[0003] In order to endow fibers with functionality, antibacterial finishing is a common post-treatment technology. However, existing antibacterial fibers mostly use physical blending or simple adsorption to introduce antibacterial agents into the fibers. Physical blending is prone to cause the inactivation of antibacterial agents due to high temperature during processing, and the antibacterial agents are easily dissolved out of the fibers after multiple washes, resulting in poor antibacterial durability and potential environmental and health risks. Simple adsorption has problems such as weak binding force, low loading capacity of antibacterial agents and uneven distribution.

[0004] In addition, polyesters and other high molecular weight materials are inherently flammable, posing a fire safety hazard. Conventional flame-retardant modification methods usually involve directly adding small molecule flame retardants during polymerization or spinning. Such flame retardants also have problems such as easy migration and precipitation, which not only affect the durability of the flame-retardant effect, but also may damage the mechanical properties of the fibers and raise concerns about toxicity. At the same time, fibers are prone to aging, yellowing and strength reduction due to ultraviolet radiation during long-term use, affecting their service life.

[0005] Therefore, those skilled in the art have been seeking a fiber solution with excellent comprehensive performance. The existing technology cannot simultaneously achieve efficient and durable antibacterial performance, intrinsic flame-retardant properties, good ultraviolet aging resistance and environmental degradability in the same fiber material.

[0006] Based on this, the present application aims to provide a degradable antibacterial fiber and a preparation method thereof, which integrates functional components stably in the fiber through the design and synthesis of special antibacterial agents, the construction of reactive polymer flame retardants, the surface modification of nanomaterials and the final chemical bonding, in order to solve one or more technical problems in the prior art. SUMMARY

[0007] The present application aims to provide a degradable antibacterial fiber and a preparation method thereof to solve the problems in the prior art.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A biodegradable antibacterial fiber, wherein the biodegradable antibacterial fiber is obtained by treating modified polyester fiber with a post-treatment solution made of an antibacterial agent; As an optimization, the modified polyester fiber is obtained by melt spinning a modified polyester blend with modified nano-titanium dioxide; As an optimization, the modified nano-titanium dioxide is prepared by reacting nano-titanium dioxide with hydrolyzed 3-aminopropyltrimethoxysilane, and then reacting it with thiodipropionic acid. As an optimization, the modified polyester is prepared by dehydration condensation of 1,4-butanediol, 1,5-glutaric acid, modified flame retardant, and 1,2,3,4-cyclobutanediol dianhydride. As an optimization, the modified flame retardant is prepared by reacting a flame retardant solution with a diphenylmethane diisocyanate solution and then with trihydroxy-1,5-glutaric acid. As an optimization, the flame retardant solution is prepared by mixing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-dimethylaminopyridine and N,N-dimethylformamide; As an optimization, the diphenylmethane diisocyanate solution is prepared by mixing diphenylmethane diisocyanate and N,N-dimethylformamide; As an optimization, the antibacterial agent is prepared by reacting 2-methylbenzoic acid with methanol, then with hydrazine hydrate, and finally with S-isomethylthiourea methyl sulfate.

[0009] A method for preparing a biodegradable antibacterial fiber, the method comprising the following preparation steps: (1) 1,4-Butanediol, 1,5-glutaric acid, modified flame retardant, 1,2,3,4-cyclobutanediol dianhydride and antimony trioxide were mixed in a molar ratio of 1:(0.8~0.9):0.05:0.05:0.0001 and stirred for 12 h at 250~270℃. The gas pressure was reduced to 1 mmHg and the temperature was raised to 270~290℃. The mixture was stirred for 12 h to obtain the modified polyester. (2) Thiodipropionic acid and N,N-dimethylformamide were mixed in a mass ratio of 1:(20~22) to prepare an antioxidant solution; pre-modified nano titanium dioxide and antioxidant solution were mixed in a mass-volume ratio of 1g:50ml, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added in 0.01 times the volume of antioxidant solution. The mixture was stirred for 6~8h, centrifuged, washed 3 times with anhydrous ethanol, and dried at 60~70℃ for 12~14h to obtain modified nano titanium dioxide; (3) The modified nano-titanium dioxide and modified polyester in a mass ratio of 1:(19~21) are mixed and added into a melt spinning machine, and melt spinning is performed to obtain modified polyester fiber.

[0010] (4) Mix antibacterial agent, N,N-dimethylformamide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass-volume ratio of 1g:10ml:0.01g:0.01g to prepare a post-treatment solution. Immerse the modified polyester fiber in the post-treatment solution, heat to 50~60℃, react for 5~6h, remove, wash with deionized water 3 times, and dry at 50~60℃ for 10~12h to obtain degradable antibacterial fiber.

[0011] As an optimization, the preparation method of the pre-modified nano titanium dioxide in step (1) is as follows: take a diphenylmethane diisocyanate solution and a flame retardant solution with a volume ratio of 1:1, add the flame retardant solution to the diphenylmethane diisocyanate solution under nitrogen atmosphere for one hour, control the temperature at 55~65℃, continue the reaction for 5h, add trihydroxy-1,5-pentanoic acid with a volume of 10~11 times that of the diphenylmethane diisocyanate solution, let stand for 12h, vacuum filter, wash three times with anhydrous ethanol, and dry at 50~60℃ for 8h to obtain the modified flame retardant.

[0012] As an optimization, the diphenylmethane diisocyanate solution is prepared by mixing diphenylmethane diisocyanate and N,N-dimethylformamide in a molar volume ratio of 0.2 mol: 200 mL to prepare a diphenylmethane diisocyanate solution.

[0013] As an optimization, the method for preparing the flame retardant solution is as follows: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-dimethylaminopyridine and N,N-dimethylformamide are mixed in a mass-to-volume ratio of 1g:(0.008~0.009)g:(4~5)mL to prepare a flame retardant solution.

[0014] As an optimization, the modified nano-titanium dioxide in step (2) is prepared by mixing thiodipropionic acid and N,N-dimethylformamide in a mass ratio of 1:(20~22) to prepare an antioxidant solution; mixing pre-modified nano-titanium dioxide and antioxidant solution in a mass-volume ratio of 1g:50ml, adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide at 0.01 times the volume of antioxidant solution, stirring for 6~8h, centrifuging, washing 3 times with anhydrous ethanol, and drying at 60~70℃ for 12~14h to obtain modified nano-titanium dioxide.

[0015] As an optimization, the pre-modified nano-titanium dioxide is prepared by mixing 3-aminopropyltrimethoxysilane and deionized water in a mass ratio of (19~20):(98~100), adjusting the pH to 3~4 with 1mol / L hydrochloric acid, and stirring magnetically at 1000rpm for 30~45min to obtain a silane hydrolysate; adding nano-titanium dioxide at 0.05 times the mass of 3-aminopropyltrimethoxysilane to the silane hydrolysate, stirring at 500rpm at 50℃ for 1~2h, centrifuging for 15min, washing three times with deionized water, and drying at 80℃ for 10~12h to obtain the pre-modified nano-titanium dioxide.

[0016] As an optimization, the melt spinning in step (3) has the following parameters: spinning temperature of 285~295℃, winding speed of 3000~4000m / min, stretching ratio of 3.8~4.0, and air cooling.

[0017] As an optimization, the antibacterial agent in step (4) is prepared by: mixing 2-methylbenzoic acid and methanol in a molar ratio of 1:(1~1.02), adding a concentrated sulfuric acid solution of 1.61 g / mL containing 0.05 times the molar amount of sulfuric acid of 2-methylbenzoic acid, reacting at 60~70℃ for 6~8 h, distilling under reduced pressure, extracting with dichloromethane, and then distilling under reduced pressure again to obtain methyl 2-methylbenzoate; mixing 2-methylbenzoate ester and hydrazine hydrate in a molar ratio of 1:(1~1.02), 2-Toluenehydrazine was prepared by stirring the reaction at 15-25℃ for 12-16 hours, filtering, and drying at 60-70℃ for 8 hours. 2-Toluenehydrazine and S-isomethylthiourea methyl sulfate in a molar ratio of 1:(1-1.02) were dissolved in 100 times the mass of S-isomethylthiourea methyl sulfate in deionized water. The mixture was refluxed at 95-105℃ for 6 hours, distilled under reduced pressure, washed three times with ethanol, filtered, dried at 60-70℃, and the pH was adjusted to 8-9 with 10% sodium hydroxide solution. The mixture was then refluxed at 100℃ for 12 hours. The pH was adjusted to 7 with 0.1 mol / L hydrochloric acid solution at 0℃, filtered, washed three times with deionized water, and dried at 60-70℃ for 12 hours to obtain the antibacterial agent.

[0018] As an optimization, the nano-titanium dioxide is of model JH-005Ti-D35n-B40, purchased from Shijiazhuang Jinghuang Technology Co., Ltd. Compared with the prior art, the beneficial effects achieved by the present invention are: In the preparation of biodegradable antibacterial fibers, this invention... First, 2-methylbenzoic acid reacts with methanol, then with hydrazine hydrate, and finally with S-isomethylthiourea methyl sulfate to prepare the antibacterial agent. The antibacterial agent contains three nitrogen atoms and possesses strong electron-donating and coordinating abilities. It can chelate with metal ions within bacterial cells to form stable complexes, thereby inhibiting the activity of metal-dependent enzymes, such as DNA polymerase and respiratory chain dehydrogenase, and blocking cellular energy metabolism and nucleic acid replication processes to achieve an antibacterial effect.

[0019] Secondly, a modified polyester was prepared by dehydration condensation of 1,4-butanediol, 1,5-glutaric acid, a modified flame retardant, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride. Modified nano-titanium dioxide was then prepared by reacting nano-titanium dioxide with hydrolyzed 3-aminopropyltrimethoxysilane, followed by reaction with thiodipropionic acid. Modified polyester fibers were obtained by melt spinning the modified polyester with the modified nano-titanium dioxide. Modified flame retardants participate in copolymerization, introducing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide onto the fiber side chains. 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is a flame retardant that decomposes during combustion under heat to generate phosphorus-containing free radicals and phosphates. It inhibits the combustion chain reaction through gas-phase free radical capture and generates polyphosphoric acid and a stable carbon layer in the condensed phase, forming a heat-insulating and oxygen-barrier barrier to achieve flame retardancy. 1,2,3,4-cyclobutanedicarboxylic dianhydride participates in copolymerization, introducing carboxyl groups onto the fiber side chains, providing covalently bonded reactive groups for subsequent antibacterial agents. Thiodipropionate antioxidants decompose peroxides generated during polymer oxidation, converting them into stable alcohols, while simultaneously oxidizing themselves to sulfoxides or sulfones, effectively blocking the continuation of the oxidation chain reaction. Together with titanium dioxide, they absorb photons to form a dual anti-photoaging system against reactive oxygen species.

[0020] Finally, biodegradable antibacterial fibers were obtained by treating modified polyester fibers with a post-treatment solution made of an antibacterial agent. The amino groups on the antibacterial agent react and combine with the carboxyl groups on the fiber surface, covalently linking the antibacterial agent to the fiber, thereby enhancing the duration of the antibacterial effect and the wash resistance of the fiber. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Implementation: 1:

[0022] A method for preparing a biodegradable antibacterial fiber, the method comprising the following preparation steps: (1) Mix 2-methylbenzoic acid and methanol in a molar ratio of 1:1, add a concentrated sulfuric acid solution containing 1.61 g / mL of sulfuric acid with a molar weight of 0.05 times that of 2-methylbenzoic acid, react at 60 °C for 6 h, distill under reduced pressure, extract with dichloromethane, and then distill under reduced pressure again to obtain methyl 2-methylbenzoate; mix 2-methylbenzoate ester and hydrazine hydrate in a molar ratio of 1:1, stir and react at 15 °C for 12 h, filter, and dry at 60 °C for 8 h to obtain 2-toluamide hydrazine; dissolve 2-toluamide hydrazine and S-isomethylthiourea methyl sulfate in a molar ratio of 1:1 in deionized water with a mass of 100 times that of S-isomethylthiourea methyl sulfate, reflux at 95 °C for 6 h, distill under reduced pressure, wash three times with ethanol, filter, dry at 60 °C, and adjust the pH with 10% sodium hydroxide solution. 8. Reflux at 100℃ for 12 hours, adjust pH to 7 with 0.1 mol / L hydrochloric acid solution at 0℃, filter, wash three times with deionized water, and dry at 60℃ for 12 hours to obtain the antibacterial agent. (2) A diphenylmethane diisocyanate and N,N-dimethylformamide were mixed in a molar volume ratio of 0.2 mol: 200 mL to prepare a diphenylmethane diisocyanate solution; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-dimethylaminopyridine and N,N-dimethylformamide were mixed in a mass-volume ratio of 1 g: 0.008 g: 4 mL to prepare a flame retardant solution; a diphenylmethane diisocyanate solution and a flame retardant solution were taken in a volume ratio of 1:1, and the flame retardant solution was added to the diphenylmethane diisocyanate solution under a nitrogen atmosphere for one hour. The temperature was controlled at 55℃ and the reaction was continued for 5 hours. Trihydroxy-1,5-glutaric acid with a volume of 10 times that of the diphenylmethane diisocyanate solution was added, and the mixture was allowed to stand for 12 hours. The mixture was then vacuum filtered, washed three times with anhydrous ethanol, and dried at 50℃ for 8 hours to obtain a modified flame retardant. (3) 1,4-Butanediol, 1,5-glutaric acid, modified flame retardant, 1,2,3,4-cyclobutanediol dianhydride and antimony trioxide in a molar ratio of 1:0.8:0.05:0.05:0.0001 were mixed and stirred at 250°C for 12 h. The gas pressure was reduced to 1 mmHg and the temperature was raised to 270°C. The mixture was stirred at 270°C for 12 h to obtain the modified polyester. (4) Mix 3-aminopropyltrimethoxysilane and deionized water at a mass ratio of 19:98, adjust the pH to 3 with 1 mol / L hydrochloric acid, and stir magnetically at 1000 rpm for 30 min to obtain a silane hydrolysate; add 0.05 times the mass of 3-aminopropyltrimethoxysilane nano-titanium dioxide to the silane hydrolysate, stir at 500 rpm at 50℃ for 1 h, centrifuge for 15 min, wash three times with deionized water, and dry at 80℃ for 10 h to obtain pre-modified nano-titanium dioxide. Titanium dioxide; an antioxidant solution was prepared by mixing thiodipropionic acid and N,N-dimethylformamide in a mass ratio of 1:20; pre-modified nano-titanium dioxide and the antioxidant solution were mixed in a mass-volume ratio of 1g:50ml, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added at 0.01 times the volume of the antioxidant solution. The mixture was stirred for 6 hours, centrifuged, washed three times with anhydrous ethanol, and dried at 60℃ for 12 hours to obtain modified nano-titanium dioxide; (5) The modified nano-titanium dioxide and modified polyester were mixed in a mass ratio of 1:19 and added to a melt spinning machine. The melt spinning was carried out at a spinning temperature of 285℃, a winding speed of 3000m / min, a stretch ratio of 3.8, and air-cooled to obtain modified polyester fiber.

[0023] (6) Mix antibacterial agent, N,N-dimethylformamide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass-volume ratio of 1g:10ml:0.01g:0.01g to prepare a post-treatment solution. Immerse the modified polyester fiber in the post-treatment solution, heat to 50°C, react for 5 hours, remove, wash with deionized water 3 times, and dry at 50°C for 10 hours to obtain degradable antibacterial fiber. Implementation: 2:

[0024] A method for preparing a biodegradable antibacterial fiber, the method comprising the following preparation steps: (1) Mix 2-methylbenzoic acid and methanol in a molar ratio of 1:1.01, add a concentrated sulfuric acid solution containing 1.61 g / mL of sulfuric acid with a molar weight of 0.05 times that of 2-methylbenzoic acid, react at 65 °C for 7 h, distill under reduced pressure, extract with dichloromethane, and distill under reduced pressure again to obtain methyl 2-methylbenzoate; mix 2-methylbenzoate ester and hydrazine hydrate in a molar ratio of 1:1.01, stir and react at 20 °C for 14 h, filter, and dry at 65 °C for 8 h to obtain 2-toluamide hydrazine; dissolve 2-toluamide hydrazine and S-isomethylthiourea methyl sulfate in a molar ratio of 1:1.01 in deionized water with a mass of 100 times that of S-isomethylthiourea methyl sulfate, reflux at 100 °C for 6 h, distill under reduced pressure, wash three times with ethanol, filter, dry at 65 °C, and adjust the pH with 10% sodium hydroxide solution. 8.5, reflux reaction at 100℃ for 12h, adjust pH to 7 with 0.1mol / L hydrochloric acid solution at 0℃, filter, wash three times with deionized water, and dry at 65℃ for 12h to obtain antibacterial agent; (2) A diphenylmethane diisocyanate and N,N-dimethylformamide were mixed in a molar volume ratio of 0.2 mol: 200 mL to prepare a diphenylmethane diisocyanate solution; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-dimethylaminopyridine and N,N-dimethylformamide were mixed in a mass-volume ratio of 1 g: 0.0085 g: 4.5 mL to prepare a flame retardant solution; a diphenylmethane diisocyanate solution and a flame retardant solution were taken in a volume ratio of 1:1, and the flame retardant solution was added to the diphenylmethane diisocyanate solution under a nitrogen atmosphere for one hour. The temperature was controlled at 60 °C and the reaction was continued for 5 h. Trihydroxy-1,5-glutaric acid with a volume of 10.5 times that of the diphenylmethane diisocyanate solution was added, and the mixture was allowed to stand for 12 h. The mixture was then vacuum filtered, washed three times with anhydrous ethanol, and dried at 55 °C for 8 h to obtain a modified flame retardant. (3) 1,4-Butanediol, 1,5-glutaric acid, modified flame retardant, 1,2,3,4-cyclobutanediol dianhydride and antimony trioxide in a molar ratio of 1:0.85:0.05:0.05:0.0001 were mixed and stirred at 260°C for 12 h. The gas pressure was reduced to 1 mmHg and the temperature was raised to 280°C. The mixture was stirred at 280°C for 12 h to obtain the modified polyester. (4) Mix 3-aminopropyltrimethoxysilane and deionized water at a mass ratio of 19.5:99, adjust the pH to 3.5 with 1 mol / L hydrochloric acid, and stir magnetically at 1000 rpm for 37.5 min to obtain silane hydrolysate; add nano-titanium dioxide at 0.05 times the mass of 3-aminopropyltrimethoxysilane to the silane hydrolysate, stir at 500 rpm at 50℃ for 1.5 h, centrifuge for 15 min, wash three times with deionized water, and dry at 80℃ for 11 h to obtain pre-modified silane. Modified nano-titanium dioxide was prepared by mixing thiodipropionic acid and N,N-dimethylformamide in a mass ratio of 1:21 to obtain an antioxidant solution; pre-modified nano-titanium dioxide and the antioxidant solution were mixed in a mass-volume ratio of 1g:50ml, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added at 0.01 times the volume of the antioxidant solution. The mixture was stirred and reacted for 7h, centrifuged, washed three times with anhydrous ethanol, and dried at 65℃ for 13h to obtain modified nano-titanium dioxide. (5) The modified nano-titanium dioxide and modified polyester were mixed in a mass ratio of 1:20 and added to a melt spinning machine. The melt spinning was carried out at a spinning temperature of 290℃, a winding speed of 3500m / min, a stretch ratio of 3.9, and air-cooled to obtain modified polyester fiber.

[0025] (6) Mix antibacterial agent, N,N-dimethylformamide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass-volume ratio of 1g:10ml:0.01g:0.01g to prepare a post-treatment solution. Immerse the modified polyester fiber in the post-treatment solution, heat to 55°C, react for 5.5h, remove, wash with deionized water 3 times, and dry at 55°C for 11h to obtain degradable antibacterial fiber. Implementation: 3:

[0026] A method for preparing a biodegradable antibacterial fiber, the method comprising the following preparation steps: (1) Mix 2-methylbenzoic acid and methanol in a molar ratio of 1:1.02, add a concentrated sulfuric acid solution containing 1.61 g / mL of sulfuric acid with a molar weight of 0.05 times that of 2-methylbenzoic acid, react at 70 °C for 8 h, distill under reduced pressure, extract with dichloromethane, and distill under reduced pressure again to obtain methyl 2-methylbenzoate; mix 2-methylbenzoate ester and hydrazine hydrate in a molar ratio of 1:1.02, stir and react at 25 °C for 16 h, filter, and dry at 70 °C for 8 h to obtain 2-toluamide hydrazine; dissolve 2-toluamide hydrazine and S-isomethylthiourea methyl sulfate in a molar ratio of 1:1.02 in deionized water with a mass of 100 times that of S-isomethylthiourea methyl sulfate, reflux at 105 °C for 6 h, distill under reduced pressure, wash three times with ethanol, filter, dry at 70 °C, and adjust the pH with 10% sodium hydroxide solution. 9. The reaction was refluxed at 100℃ for 12 hours. The pH was adjusted to 7 with 0.1 mol / L hydrochloric acid solution at 0℃. The mixture was filtered, washed three times with deionized water, and dried at 70℃ for 12 hours to obtain the antibacterial agent. (2) A diphenylmethane diisocyanate and N,N-dimethylformamide were mixed in a molar volume ratio of 0.2 mol: 200 mL to prepare a diphenylmethane diisocyanate solution; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-dimethylaminopyridine and N,N-dimethylformamide were mixed in a mass-volume ratio of 1 g: 0.009 g: 5 mL to prepare a flame retardant solution; a diphenylmethane diisocyanate solution and a flame retardant solution were taken in a volume ratio of 1:1, and the flame retardant solution was added to the diphenylmethane diisocyanate solution under a nitrogen atmosphere for one hour. The temperature was controlled at 65℃ and the reaction was continued for 5 hours. Trihydroxy-1,5-glutaric acid with a volume of 11 times that of the diphenylmethane diisocyanate solution was added, and the mixture was allowed to stand for 12 hours. The mixture was then vacuum filtered, washed three times with anhydrous ethanol, and dried at 60℃ for 8 hours to obtain a modified flame retardant. (3) 1,4-Butanediol, 1,5-glutaric acid, modified flame retardant, 1,2,3,4-cyclobutanediol dianhydride and antimony trioxide in a molar ratio of 1:0.9:0.05:0.05:0.0001 were mixed and stirred at 270°C for 12 h. The gas pressure was reduced to 1 mmHg and the temperature was raised to 290°C. The mixture was stirred at 290°C for 12 h to obtain the modified polyester. (4) Mix 3-aminopropyltrimethoxysilane and deionized water at a mass ratio of 20:100, adjust the pH to 4 with 1 mol / L hydrochloric acid, and stir magnetically at 1000 rpm for 45 min to obtain silane hydrolysate; add nano-titanium dioxide at a mass ratio of 0.05 times that of 3-aminopropyltrimethoxysilane to the silane hydrolysate, stir at 500 rpm at 50℃ for 1-2 h, centrifuge for 15 min, wash three times with deionized water, and dry at 80℃ for 12 h to obtain pre-modified nano-titanium dioxide. Modified nano-titanium dioxide was prepared by mixing thiodipropionic acid and N,N-dimethylformamide in a mass ratio of 1:22 to obtain an antioxidant solution; pre-modified nano-titanium dioxide and the antioxidant solution were mixed in a mass-volume ratio of 1g:50ml, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added at 0.01 times the volume of the antioxidant solution. The mixture was stirred for 8 hours, centrifuged, washed three times with anhydrous ethanol, and dried at 70℃ for 14 hours to obtain modified nano-titanium dioxide. (5) The modified nano-titanium dioxide and modified polyester were mixed in a mass ratio of 1:21 and added to a melt spinning machine. The melt spinning was carried out at a spinning temperature of 295℃, a winding speed of 4000m / min, a stretch ratio of 4.0, and air-cooled to obtain modified polyester fiber.

[0027] (6) Mix antibacterial agent, N,N-dimethylformamide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass-volume ratio of 1g:10ml:0.01g:0.01g to prepare a post-treatment solution. Immerse the modified polyester fiber in the post-treatment solution, heat to 60℃, react for 6h, remove, wash with deionized water 3 times, and dry at 50~60℃ for 12h to obtain degradable antibacterial fiber.

[0028] Comparative Example 1: The difference between the preparation method of the biodegradable antibacterial fiber in Comparative Example 1 and Example 2 is that steps (1) and (6) are omitted, and step (5) is modified as follows: modified nano-titanium dioxide and modified polyester in a mass ratio of 1:21 are mixed and added to a melt spinning machine, melt-spun at a spinning temperature of 295°C, a winding speed of 4000 m / min, a stretch ratio of 4.0, and air-cooled to obtain the biodegradable antibacterial fiber. The remaining steps are the same as in Example 2.

[0029] Comparative Example 2: The preparation method of the biodegradable antibacterial fiber in Comparative Example 2 differs from that in Example 2 in that step (2) is omitted, and step (3) is modified as follows: 1,4-butanediol, 1,5-glutaric acid, 1,2,3,4-cyclobutanediol dianhydride, and antimony trioxide are mixed in a molar ratio of 1:0.9:0.05:0.0001, and stirred at 270°C for 12 hours. The gas pressure is then reduced to 1 mmHg, the temperature is raised to 290°C, and the reaction is continued for 12 hours to obtain the modified polyester. The remaining steps are the same as in Example 2.

[0030] Comparative Example 3: The difference between the preparation method of the biodegradable antibacterial fiber in Comparative Example 3 and Example 2 is that step (4) is omitted, and step (5) is modified as follows: modified thiodipropionic acid and modified polyester are mixed at a mass ratio of 1:20 and added to a melt spinning machine for melt spinning. The spinning temperature is 290°C, the winding speed is 3500 m / min, the stretch ratio is 3.9, and the fiber is cooled by air to obtain the modified polyester fiber. The remaining steps are the same as in Example 2.

[0031] Comparative Example 4: The preparation method of the biodegradable antibacterial fiber in Comparative Example 4 differs from that in Example 2 only in step (4). Step (5) is modified as follows: nano-titanium dioxide and modified polyester are mixed at a mass ratio of 1:20 and added to a melt spinning machine for melt spinning. The spinning temperature is 290°C, the winding speed is 3500 m / min, the stretch ratio is 3.9, and the fibers are cooled by air to obtain modified polyester fibers. The remaining steps are the same as in Example 2.

[0032] Test Example 1 Antibacterial performance test Test method: According to GB / T20944.3-2008 "Evaluation of Antimicrobial Properties of Textiles - Part III: Shaking Method": The test strain was Staphylococcus aureus. A bacterial suspension with a concentration of 1.0 × 10^5 CFU / mL (the required volume) was taken. Fabrics and cotton control examples of the required size (Examples 1-3, Comparative Examples 1-4) were placed into sealed containers containing the bacterial suspension at 20℃ and continuously shaken for 18 hours. The bacterial suspension was then cultured, and the inhibition rate was calculated. The results are shown in Table 1.

[0033] Table 1 Antibacterial rate (%) Antibacterial rate (%) Example 1 99.7 Comparative Example 1 5.0 Example 2 99.8 Comparative Example 2 95.5 Example 3 99.8 Comparative Example 3 94.7 Comparative Example 4 96.1 A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-4 in Table 1 reveals that the biodegradable antibacterial fiber prepared by this invention has good antibacterial properties.

[0034] By comparison, Examples 1-3 exhibit stronger antibacterial properties than Comparative Example 1. The difference between Examples 1-3 and Comparative Example 1 lies in whether an antibacterial agent is covalently bound. The antibacterial agent contains three nitrogen atoms and possesses strong electron donor and coordination capabilities. It can chelate with metal ions within bacterial cells to form stable complexes, thereby inhibiting the activity of metal ion-dependent enzymes, such as DNA polymerase and respiratory chain dehydrogenase, and blocking cellular energy metabolism and nucleic acid replication processes to achieve an antibacterial effect.

[0035] Test Example 2 Flame retardancy performance testing Test method: The limiting oxygen index of the examples and comparative examples was tested using an oxygen index instrument according to GB / T5454 "Test for Burning Performance of Textiles - Oxygen Index Method". The results are shown in Table 2.

[0036] Table 2 Limiting oxygen index (%) Limiting oxygen index (%) Example 1 29.7 Comparative Example 1 28.3 Example 2 30.1 Comparative Example 2 20.6 Example 3 29.9 Comparative Example 3 28.6 Comparative Example 4 29.4 A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-4 in Table 2 reveals that the biodegradable antibacterial fiber prepared by this invention has good flame retardant properties.

[0037] By comparison, Examples 1-3 showed stronger flame retardant performance compared to Comparative Example 2. Examples 1-3 involved copolymerization with modified flame retardants, introducing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide into the fiber backbone. 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is a flame retardant that can decompose into phosphorus-containing free radicals and phosphoric acid substances during combustion and heating. It inhibits the combustion chain reaction through gas-phase free radical capture and generates polyphosphoric acid and a stable carbon layer in the condensed phase, forming a heat insulation and oxygen barrier to achieve the flame retardant effect.

[0038] Test Example 3 Testing of antioxidant aging performance Test method: Referring to GB / T7141-2008 "Test Method for Thermal Aging of Plastics", the fabric samples of the examples and comparative examples were placed in a thermal aging test chamber at 135℃ for 72 hours to simulate a long-term thermo-oxidative aging process. Before and after treatment, the breaking strength A and breaking strength B of the examples and comparative examples were tested using a universal testing machine according to the fabric strength testing standard (such as GB / T3923.1), and the rate of change of breaking strength before and after thermo-oxidative aging treatment was calculated; the rate of change of breaking strength = (AB) / A × 100%. The results are shown in Table 3.

[0039] Table 3 Change rate of breaking strength (%) Change rate of breaking strength (%) Example 1 4.3 Comparative Example 1 3.8 Example 2 4.2 Comparative Example 2 4.0 Example 3 3.9 Comparative Example 3 4.7 Comparative Example 4 15.9 A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-4 in Table 3 reveals that the biodegradable antibacterial fiber prepared by this invention has good antioxidant aging resistance.

[0040] By comparison, Examples 1-3 have stronger antioxidant aging resistance than Comparative Example 4. The difference between Examples 1-3 and Comparative Example 4 is whether or not thiodipropionate is used as a blend. Thiodipropionate antioxidants decompose the peroxides generated during polymer oxidation and convert them into stable alcohols. At the same time, they oxidize themselves into sulfoxides or sulfones, thereby effectively blocking the continuation of the oxidation chain reaction.

[0041] Test Example 4 Test of resistance to photoaging Test method: Referring to GB / T3916-2013, single yarns of the waterproof and stain-resistant fabrics of Examples 1-3 and Comparative Examples 1-5 were taken, and the breaking strength A was tested using a YG061F electronic single yarn strength tester. The examples and comparative examples were irradiated with a xenon lamp for 10 days, and the breaking strength B of the single yarns of Examples 1-3 and Comparative Examples 1-5 after ultraviolet light treatment was tested. The rate of change of breaking strength of the examples and comparative examples before and after ultraviolet aging treatment was calculated; the rate of change of breaking strength = (AB) / A × 100%. The results are shown in Table 4.

[0042] Table 4 Change rate of breaking strength (%) Change rate of breaking strength (%) Example 1 3.2 Comparative Example 1 3.2 Example 2 2.9 Comparative Example 2 3.8 Example 3 3.1 Comparative Example 3 23.4 Comparative Example 4 5.1 A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-4 in Table 3 reveals that the biodegradable antibacterial fiber prepared by this invention has good resistance to photoaging.

[0043] By comparison, Examples 1-3 showed stronger resistance to photoaging than Comparative Example 3. The difference between Examples 1-3 and Comparative Example 3 lies in whether titanium dioxide is used as a filler. When titanium dioxide is used as a fiber filler, its anti-photoaging mechanism mainly involves forming a physical barrier inside and on the surface of the fiber. Through the reflection, scattering, and absorption of ultraviolet rays by its fine particles, it effectively blocks ultraviolet rays from penetrating the fiber. This not only significantly reduces the chance of ultraviolet rays directly degrading the fiber polymer molecular chains, thereby delaying the photoaging of the fiber material and extending its service life, but also reduces the amount of ultraviolet radiation that passes through the fabric, indirectly protecting the covered object or skin.

[0044] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment 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 within the scope of protection of the present invention.

Claims

1. A biodegradable antibacterial fiber, characterized in that, The biodegradable antibacterial fiber is obtained by treating modified polyester fiber with a post-treatment solution made of antibacterial agent. The modified polyester fiber is obtained by melt spinning of modified polyester mixed with modified nano-titanium dioxide; The modified nano-titanium dioxide is prepared by reacting nano-titanium dioxide with hydrolyzed 3-aminopropyltrimethoxysilane, and then reacting it with thiodipropionic acid. The modified polyester is prepared by dehydration condensation of 1,4-butanediol, 1,5-glutaric acid, modified flame retardant, and 1,2,3,4-cyclobutanediol dianhydride. The modified flame retardant is prepared by reacting a flame retardant solution with a diphenylmethane diisocyanate solution and then with trihydroxy-1,5-glutaric acid. The flame retardant solution is prepared by mixing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-dimethylaminopyridine and N,N-dimethylformamide; The diphenylmethane diisocyanate solution was prepared by mixing diphenylmethane diisocyanate and N,N-dimethylformamide. The antibacterial agent is prepared by reacting 2-methylbenzoic acid with methanol, then with hydrazine hydrate, and finally with S-isomethylthiourea methyl sulfate.

2. A method for preparing a biodegradable antibacterial fiber, characterized in that, The method for preparing the biodegradable antibacterial fiber includes the following preparation steps: (1) 1,4-Butanediol, 1,5-glutaric acid, modified flame retardant, 1,2,3,4-cyclobutanediol dianhydride and antimony trioxide were mixed in a molar ratio of 1:(0.8~0.9):0.05:0.05:0.0001 and stirred for 12 h at 250~270℃. The gas pressure was reduced to 1 mmHg and the temperature was raised to 270~290℃. The mixture was stirred for 12 h to obtain the modified polyester. (2) Thiodipropionic acid and N,N-dimethylformamide were mixed in a mass ratio of 1:(20~22) to prepare an antioxidant solution; pre-modified nano titanium dioxide and antioxidant solution were mixed in a mass-volume ratio of 1g:50ml, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added in 0.01 times the volume of antioxidant solution. The mixture was stirred for 6~8h, centrifuged, washed 3 times with anhydrous ethanol, and dried at 60~70℃ for 12~14h to obtain modified nano titanium dioxide; (3) Modified nano-titanium dioxide and modified polyester with a mass ratio of 1:(19~21) are mixed and added into a melt spinning machine, and melt-spun to obtain modified polyester fiber; (4) Mix antibacterial agent, N,N-dimethylformamide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in a mass-volume ratio of 1g:10ml:0.01g:0.01g to prepare a post-treatment solution. Immerse the modified polyester fiber in the post-treatment solution, heat to 50~60℃, react for 5~6h, remove, wash with deionized water 3 times, and dry at 50~60℃ for 10~12h to obtain degradable antibacterial fiber.

3. The method for preparing a biodegradable antibacterial fiber according to claim 2, characterized in that, The preparation method of the pre-modified nano titanium dioxide in step (1) is as follows: take a diphenylmethane diisocyanate solution and a flame retardant solution with a volume ratio of 1:1, add the flame retardant solution to the diphenylmethane diisocyanate solution under nitrogen atmosphere for one hour, control the temperature at 55~65℃, continue the reaction for 5h, add trihydroxy-1,5-glutaric acid with a volume of 10~11 times that of the diphenylmethane diisocyanate solution, let stand for 12h, vacuum filter, wash three times with anhydrous ethanol, and dry at 50~60℃ for 8h to obtain the modified flame retardant.

4. The method for preparing a biodegradable antibacterial fiber according to claim 3, characterized in that, The diphenylmethane diisocyanate solution is prepared by mixing diphenylmethane diisocyanate and N,N-dimethylformamide in a molar volume ratio of 0.2 mol: 200 mL to obtain a diphenylmethane diisocyanate solution.

5. The method for preparing a biodegradable antibacterial fiber according to claim 3, characterized in that, The flame retardant solution is prepared by mixing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4-dimethylaminopyridine and N,N-dimethylformamide in a mass-to-volume ratio of 1g:(0.008~0.009)g:(4~5)mL to prepare a flame retardant solution.

6. The method for preparing a biodegradable antibacterial fiber according to claim 2, characterized in that, The modified nano-titanium dioxide described in step (2) is prepared by mixing thiodipropionic acid and N,N-dimethylformamide in a mass ratio of 1:(20~22) to prepare an antioxidant solution; mixing pre-modified nano-titanium dioxide and antioxidant solution in a mass-volume ratio of 1g:50ml, adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide at 0.01 times the volume of the antioxidant solution, stirring for 6~8h, centrifuging, washing three times with anhydrous ethanol, and drying at 60~70℃ for 12~14h to obtain modified nano-titanium dioxide.

7. The method for preparing a biodegradable antibacterial fiber according to claim 6, characterized in that, The pre-modified nano-titanium dioxide is prepared by mixing 3-aminopropyltrimethoxysilane and deionized water in a mass ratio of (19~20):(98~100), adjusting the pH to 3~4 with 1mol / L hydrochloric acid, and stirring magnetically at 1000rpm for 30~45min to obtain a silane hydrolysate; adding 0.05 times the mass of 3-aminopropyltrimethoxysilane nano-titanium dioxide to the silane hydrolysate, stirring at 500rpm at 50℃ for 1~2h, centrifuging for 15min, washing three times with deionized water, and drying at 80℃ for 10~12h to obtain the pre-modified nano-titanium dioxide.

8. The method for preparing a biodegradable antibacterial fiber according to claim 2, characterized in that, The melt spinning in step (3) has the following parameters: spinning temperature of 285~295℃, winding speed of 3000~4000m / min, stretching ratio of 3.8~4.0, and air cooling.

9. The method for preparing a biodegradable antibacterial fiber according to claim 2, characterized in that, The antibacterial agent described in step (4) is prepared as follows: 2-methylbenzoic acid and methanol are mixed in a molar ratio of 1:(1~1.02), and a concentrated sulfuric acid solution of 1.61 g / mL containing 0.05 times the molar amount of sulfuric acid of 2-methylbenzoic acid is added. The mixture is reacted at 60~70℃ for 6~8 h, distilled under reduced pressure, extracted with dichloromethane, and then distilled under reduced pressure again to obtain methyl 2-methylbenzoate; 2-methylbenzoate and hydrazine hydrate are mixed in a molar ratio of 1:(1~1.02), and the mixture is reacted at 1... 2-Toluenehydrazine was prepared by stirring the reaction at 5-25℃ for 12-16 hours, filtering, and drying at 60-70℃ for 8 hours. 2-Toluenehydrazine and S-isomethylthiourea methyl sulfate in a molar ratio of 1:(1-1.02) were dissolved in 100 times the mass of S-isomethylthiourea methyl sulfate in deionized water. The mixture was refluxed at 95-105℃ for 6 hours, distilled under reduced pressure, washed three times with ethanol, filtered, dried at 60-70℃, and the pH was adjusted to 8-9 with 10% sodium hydroxide solution. The mixture was then refluxed at 100℃ for 12 hours. The pH was adjusted to 7 with 0.1 mol / L hydrochloric acid solution at 0℃, filtered, washed three times with deionized water, and dried at 60-70℃ for 12 hours to obtain the antibacterial agent.