Sulfonium salt graft modified long-acting antibacterial cotton fiber and preparation method thereof

Abstract

The invention discloses a preparation method of sulfonium salt grafted and modified long-acting antibacterial cotton fiber, which comprises the following steps: (1) uniformly mixing polycarboxylic acid, sodium phosphate, disodium hydrogen phosphate, sodium hypophosphite and water to prepare a modified solution; (2) taking a certain amount of cotton fibers, completely soaking and dispersing the cotton fibers in the modified solution, and reacting at 40-100 DEG C for 0.5-5 hours to prepare modified cotton fibers with carboxyl groups on the surfaces; (3) adding octadecyl sulfide and methyl iodide into the N, N-dimethylformamide / water solution, and reacting for 24-48 hours to obtain a solution; (4) dialyzing the solution in a 0.1 mol / L sodium chloride solution for 24 hours, and dialyzing in deionized water for 24 hours; (5) freeze-drying the dialyzed solution for 48 hours to obtain alkyl sulfonium salt; (6) soaking the modified cotton fiber in an alkaline aqueous solution, adding alkyl sulfonium salt, and stirring and reacting at 40-80 DEG C for 1-4 hours; and (7) obtaining the sulfonium salt grafted antibacterial cotton fiber. The cotton fiber disclosed by the invention has long-acting antibacterial property, mechanical property of the cotton fiber and good biological safety.

Description

Technical Field

[0001] The invention belongs to the technical field of functional fibers, and in particular relates to a sulfonium salt grafted modified long-acting antibacterial cotton fiber and a preparation method thereof. Background Art

[0002] With the rapid development of science and technology, people have put forward higher requirements for the hygienic function of textiles. Cotton fiber, as a natural textile material that has been widely used since ancient times, has excellent hygroscopicity, warmth retention, comfort and low cost, and has long been deeply rooted in all aspects of life and production. However, natural cotton fiber does not have antibacterial ability, which limits its application in more fields. Therefore, in the study of cotton fiber modification, an important research direction is to realize the antibacterial properties of cotton fiber and reduce the invasion of bacteria to the human body.

[0003] There have been many achievements in the antibacterial modification of cotton fibers. Chinese patent CN115029925A prepares plant essential oil microcapsules by compounding sweet basil extract, coptis extract, persimmon calyx extract, citronella essential oil and clove essential oil in proportion, and then scouring cotton fibers for functional treatment to obtain mosquito repellent, antibacterial and mildew-proof cotton fibers. The content of antibacterial components of Chinese herbal medicine in the modified cotton fibers obtained by this treatment is limited, which is not conducive to the durability of the antibacterial and antiviral functions of the modified cotton fibers.

[0004] Chinese patent CN114182530A uses etching to obtain hollow cotton fibers, and then prepares antibacterial and deodorizing cotton fibers adsorbed with seaweed polysaccharides, tea polyphenols and zinc ions by soaking. The modified cotton fibers obtained by this treatment method have great damage to the fibers, affecting the mechanical properties of the fibers and being unfavorable for spinning.

[0005] Chinese patent CN113089151B dissolves the core yarn of cotton fiber core-spun yarn with soluble fiber as the core layer after shaping, and then immerses the obtained cotton fiber shell yarn in an antibacterial finishing liquid composed of quaternary ammonium salt, aloe extract, etc., to prepare a three-dimensional antibacterial yarn containing cotton fiber with a full velvet surface and soft feel. However, the binding performance between the added substance and the cotton fiber is poor, which affects the durability of the antibacterial function of the cotton fiber.

[0006] In summary, the existing antibacterial treatment technologies for cotton fibers all have certain defects, and most of them have long processes, complex processes, and high costs. Therefore, how to make cotton fibers effectively obtain long-term antibacterial properties while taking into account the basic properties of cotton fibers such as mechanical properties, and being able to significantly shorten the process flow, lower the technical threshold, and significantly improve production efficiency has become a difficult problem that technicians in the field of functional fibers urgently need to solve. Summary of the invention

[0007] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a long-lasting antibacterial cotton fiber grafted and modified with sulfonium salt, which enables the cotton fiber to effectively obtain long-lasting antibacterial properties while taking into account the mechanical properties of the cotton fiber and good biological safety, and a preparation method thereof.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a long-lasting antibacterial cotton fiber grafted with sulfonium salt, comprising the following steps:

[0009] 1. Cotton fiber modification:

[0010] (1) Mix polycarboxylic acid, sodium phosphate, disodium hydrogen phosphate, sodium hypophosphite and water to obtain a modified solution for later use;

[0011] (2) taking a certain amount of cotton fiber and completely immersing and dispersing it in the modified solution, and reacting it with magnetic stirring at 40-100° C. for 0.5-5 h to obtain modified cotton fiber with carboxyl groups on the surface;

[0012] 2. Preparation of alkyl sulfonium salts:

[0013] (3) adding octadecyl thioether and methyl iodide to N,N-dimethylformamide / water solution and reacting for 24-48 hours to obtain a solution;

[0014] (4) The resulting solution was dialyzed in a 0.1 mol / L sodium chloride solution for 24 h, and then dialyzed in deionized water for 24 h;

[0015] (5) freeze-drying the dialyzed solution for 48 h to obtain an alkyl sulfonium salt;

[0016] 3. Sulfonium salt grafted cotton fiber:

[0017] (6) soaking the modified cotton fiber obtained in step (2) in an alkaline aqueous solution, adding the alkyl sulfonium salt obtained in step (5), and stirring the reaction at 40-80° C. for 1-4 h;

[0018] (7) Obtain sulfonium salt grafted antibacterial cotton fiber.

[0019] In the above-mentioned method for preparing the long-lasting antibacterial cotton fiber modified by grafting of sulfonium salt, in the step (1), the polycarboxylic acid is malic acid or citric acid, and the mass ratio of cotton fiber, water, malic acid or citric acid, sodium phosphate, disodium hydrogen phosphate, and sodium hypophosphite is 6:100:10-25:0.5:0.8:5.

[0020] The preparation method of the above-mentioned sulfonium salt grafted modified long-lasting antibacterial cotton fiber, in the step (1), the polycarboxylic acid is succinic acid or tartaric acid, and the mass ratio of cotton fiber, water, succinic acid or tartaric acid, sodium phosphate, disodium hydrogen phosphate, and sodium hypophosphite is 6:100:15-30:0.5:0.8:5.

[0021] In the above-mentioned method for preparing the long-lasting antibacterial cotton fiber modified by grafting of sulfonium salt, in the step (2), the cotton fiber is reacted in the modified solution at 80° C. with magnetic stirring for 1 hour.

[0022] In the above-mentioned method for preparing the long-lasting antibacterial cotton fiber modified by grafting of sulfonium salt, in the step (3), the mass ratio of octadecyl sulfide to methyl iodide is 1:1-5, and the mass ratio of N,N-dimethylformamide / water solution is 1:0.5-1.5.

[0023] In the above-mentioned method for preparing the long-lasting antibacterial cotton fiber grafted with sulfonium salt, in the step (6), the pH value of the alkaline aqueous solution is 9.5-10.5, and the mass ratio of alkyl sulfonium salt, cotton fiber and water is 0.5:6:100.

[0024] In the above-mentioned method for preparing the long-lasting antibacterial cotton fiber modified by grafting of sulfonium salt, in the step (6), the modified cotton fiber is immersed in an alkaline aqueous solution and stirred for reaction at 50° C. for 3 hours.

[0025] In the above-mentioned method for preparing the long-lasting antibacterial cotton fiber modified by grafting of sulfonium salt, the mass ratio of octadecyl sulfide to methyl iodide is 1:3, and the ratio of N,N-dimethylformamide / water solution is 1:0.8.

[0026] In the above-mentioned method for preparing the long-lasting antibacterial cotton fiber modified by grafting of sulfonium salt, in the step (6), the pH value of the alkaline aqueous solution is 10.

[0027] A sulfonium salt grafted modified long-acting antibacterial cotton fiber is prepared by the above preparation method.

[0028] The advantages of the long-acting antibacterial cotton fiber modified by sulfonium salt grafting and the preparation method thereof of the present invention are: the main component of the cotton fiber is cellulose, and under the catalytic action of sodium phosphate, disodium hydrogen phosphate, and sodium hypophosphite, the active hydroxyl in the cellulose reacts with the carboxylic acid in the polycarboxylic acid to obtain a modified cotton fiber with a carboxyl group on the surface. At the same time, octadecyl thioether reacts with methyl iodide to generate an alkyl sulfonium salt with a positive charge, and then in an alkaline environment, the modified cotton fiber exposes the negatively charged oxygen in the carbonyl group, and the two are connected together through the electrostatic adsorption effect to obtain an antibacterial modified cotton fiber. Therefore, the sulfonium salt compound is directly grafted on the surface of the cotton fiber, so that the cotton fiber can effectively obtain antibacterial properties, while taking into account the basic characteristics of the cotton fiber such as mechanical properties and hand feel, and can greatly shorten the process flow, reduce the technical threshold, and significantly improve production efficiency. The present invention adopts a sulfonium salt surface grafting method to give the cotton fiber a significant antibacterial effect, while ensuring the basic properties of the cotton fiber in all aspects, simplifying the processing flow, and having obvious social benefits and economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the reaction mechanism of the sulfonium salt modified antibacterial cotton fiber of the present invention;

[0030] Figure 2 This is an electron microscope photo of the antibacterial cotton fiber obtained under 25% malic acid modification conditions;

[0031] Figure 3 This is an electron microscope photo of the antibacterial cotton fiber obtained under 25% citric acid modification conditions;

[0032] Figure 4 This is an electron microscope photo of the antibacterial cotton fiber obtained under 30% succinic acid modification conditions;

[0033] Figure 5 This is an electron microscope photograph of the antibacterial cotton fiber obtained under 30% tartaric acid modification conditions. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] In the present invention, unless otherwise stated, directional words such as "upper" and "lower" generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the attached drawings; while "inside" and "outside" refer to the outline of the device. In addition, in the description of this application, the term "including" means "including but not limited to". The terms first, second, third, etc. are used only as labels and do not impose numerical requirements or establish an order. The term "plurality" means "two or more".

[0036] like Figure 1As shown, a method for preparing a long-lasting antibacterial cotton fiber grafted with sulfonium salt comprises the following steps:

[0037] 1. Cotton fiber modification:

[0038] (1) Mix polycarboxylic acid, sodium phosphate, disodium hydrogen phosphate, sodium hypophosphite and water to obtain a modified solution for later use;

[0039] (2) taking a certain amount of cotton fiber and completely immersing and dispersing it in the modification solution, and reacting it with magnetic stirring at 40-100° C. for 0.5-5 h, so that the active hydroxyl groups in the cellulose react with the carboxylic acid to produce a modified cotton fiber with a carboxyl group on the surface;

[0040] 2. Preparation of alkyl sulfonium salts:

[0041] (3) adding octadecyl thioether and methyl iodide to N,N-dimethylformamide / water solution and reacting for 24-48 hours to obtain a solution;

[0042] (4) The resulting solution was dialyzed in a 0.1 mol / L sodium chloride solution for 24 h, and then dialyzed in deionized water for 24 h;

[0043] (5) freeze-drying the dialyzed solution for 48 h to obtain an alkyl sulfonium salt;

[0044] 3. Sulfonium salt grafted cotton fiber:

[0045] (6) soaking the modified cotton fiber obtained in step (2) in an alkaline aqueous solution to expose the electronegative oxygen in the carbonyl functional group, adding the alkyl sulfonium salt obtained in step (5), stirring and reacting at 40-80° C. for 1-4 hours, and using ionic electrostatic adsorption to adsorb the sulfonium salt on the surface of the modified fiber;

[0046] (7) Obtain sulfonium salt grafted antibacterial cotton fiber.

[0047] The N,N-dimethylformamide / water solution is a mixed solution of N,N-dimethylformamide and pure water in a weight ratio of 1:0.8.

[0048] The sulfonium salt grafted antibacterial cotton fiber prepared by the above method of the present invention has three free hydroxyl groups in each glucose unit in the molecular structure of cellulose, the main component of cotton fiber. Based on the dehydration between the polycarboxylic acid and the hydroxyl group of cellulose under the catalysis of sodium hypophosphite, the polycarboxylic acid with a carboxyl group is grafted into the cellulose structure, and then the negatively charged carbonyl group is ionized in an alkaline environment, and the positively charged sulfonium salt is grafted on the fiber surface by using the electrostatic adsorption effect. The carboxyl group connecting the cellulose and the sulfonium salt forms a new chemical bond through an esterification reaction, and the sulfonium salt and the carbonyl group are connected by electrostatic adsorption, so that the molecular structure of the prepared antibacterial cotton fiber is more solid, thereby achieving long-term antibacterial performance. The cotton fiber described in the present invention includes cotton bulk fiber or a product containing cotton bulk fiber, specifically including cotton yarn or cotton blended yarn prepared by processes such as carding, pre-drawing, strip and roll, drawing, roving, spun yarn, and bobbin with cotton bulk fiber as raw material. The preparation method of the present invention can be widely used in the antibacterial modification of cellulose-based fibers, such as cotton fibers, hemp fibers (flax, hemp), viscose fibers, modal fibers, etc.

[0049] The present application is described in detail below through specific embodiments. The following embodiments are only partial embodiments of the present application and are not limitations of the present application.

[0050] Example 1

[0051] A method for preparing a long-acting antibacterial cotton fiber grafted with sulfonium salt, characterized in that it comprises the following steps:

[0052] 1. Cotton fiber modification:

[0053] (1) Mix polycarboxylic acid, sodium phosphate, disodium hydrogen phosphate, sodium hypophosphite and water to obtain a modified solution for later use; wherein the polycarboxylic acid is malic acid or citric acid, and the mass ratio of cotton fiber, water, malic acid or citric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:10:0.5:0.8:5.

[0054] (2) taking a certain amount of cotton fiber and completely immersing and dispersing it in the modified solution, and reacting it with magnetic stirring at 40°C for 5 hours to obtain modified cotton fiber with carboxyl groups on the surface;

[0055] 2. Preparation of alkyl sulfonium salts:

[0056] (3) Adding octadecyl sulfide and methyl iodide to N,N-dimethylformamide / water solution and reacting for 24 hours to obtain a solution; wherein the mass ratio of octadecyl sulfide to methyl iodide is 1:1, and the mass ratio of N,N-dimethylformamide / water solution is 1:0.5.

[0057] (4) The resulting solution was dialyzed in a 0.1 mol / L sodium chloride solution for 24 h, and then dialyzed in deionized water for 24 h;

[0058] (5) freeze-drying the dialyzed solution for 48 h to obtain an alkyl sulfonium salt;

[0059] 3. Sulfonium salt grafted cotton fiber:

[0060] (6) Soaking the modified cotton fiber obtained in step (2) in an alkaline aqueous solution, adding the alkyl sulfonium salt obtained in step (5), and stirring the reaction at 40° C. for 4 hours; wherein the pH value of the alkaline aqueous solution is 9.5, and the mass ratio of the alkyl sulfonium salt, the cotton fiber, and water is 0.5:6:100.

[0061] (7) Obtain sulfonium salt grafted antibacterial cotton fiber.

[0062] Example 2

[0063] A method for preparing a long-acting antibacterial cotton fiber grafted with sulfonium salt, characterized in that it comprises the following steps:

[0064] 1. Cotton fiber modification:

[0065] (1) Mix polycarboxylic acid, sodium phosphate, disodium hydrogen phosphate, sodium hypophosphite and water to obtain a modified solution for later use; wherein the polycarboxylic acid is malic acid or citric acid, and the mass ratio of cotton fiber, water, malic acid or citric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:20:0.5:0.8:5.

[0066] (2) taking a certain amount of cotton fiber and completely immersing and dispersing it in the modified solution, and reacting it under magnetic stirring at 80°C for 1 hour to obtain modified cotton fiber with carboxyl groups on the surface;

[0067] 2. Preparation of alkyl sulfonium salts:

[0068] (3) Adding octadecyl sulfide and methyl iodide to N,N-dimethylformamide / water solution and reacting for 36 hours to obtain a solution; wherein the mass ratio of octadecyl sulfide to methyl iodide is 1:3, and the mass ratio of the N,N-dimethylformamide / water solution is 1:0.8.

[0069] (4) The resulting solution was dialyzed in a 0.1 mol / L sodium chloride solution for 24 h, and then dialyzed in deionized water for 24 h;

[0070] (5) freeze-drying the dialyzed solution for 48 h to obtain an alkyl sulfonium salt;

[0071] 3. Sulfonium salt grafted cotton fiber:

[0072] (6) Soaking the modified cotton fiber obtained in step (2) in an alkaline aqueous solution, adding the alkyl sulfonium salt obtained in step (5), and stirring the reaction at 50° C. for 3 h; wherein the pH value of the alkaline aqueous solution is 10, and the mass ratio of the alkyl sulfonium salt, the cotton fiber, and water is 0.5:6:100.

[0073] (7) Obtain sulfonium salt grafted antibacterial cotton fiber.

[0074] Example 3

[0075] A method for preparing a long-acting antibacterial cotton fiber grafted with sulfonium salt, characterized in that it comprises the following steps:

[0076] 1. Cotton fiber modification:

[0077] (1) Mix polycarboxylic acid, sodium phosphate, disodium hydrogen phosphate, sodium hypophosphite and water to obtain a modified solution for later use; wherein the polycarboxylic acid is malic acid or citric acid, and the mass ratio of cotton fiber, water, malic acid or citric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:25:0.5:0.8:5.

[0078] (2) taking a certain amount of cotton fiber and completely immersing and dispersing it in the modified solution, and reacting it under magnetic stirring at 100°C for 0.5 h to obtain modified cotton fiber with carboxyl groups on the surface;

[0079] 2. Preparation of alkyl sulfonium salts:

[0080] (3) Adding octadecyl sulfide and methyl iodide to N,N-dimethylformamide / water solution and reacting for 48 hours to obtain a solution; wherein the mass ratio of octadecyl sulfide to methyl iodide is 1:1-5, and the mass ratio of the N,N-dimethylformamide / water solution is 1:0.5-1.5.

[0081] (4) The resulting solution was dialyzed in a 0.1 mol / L sodium chloride solution for 24 h, and then dialyzed in deionized water for 24 h;

[0082] (5) freeze-drying the dialyzed solution for 48 h to obtain an alkyl sulfonium salt;

[0083] 3. Sulfonium salt grafted cotton fiber:

[0084] (6) Soaking the modified cotton fiber obtained in step (2) in an alkaline aqueous solution, adding the alkyl sulfonium salt obtained in step (5), and stirring the reaction at 80° C. for 1 h; wherein the pH value of the alkaline aqueous solution is 10.5, and the mass ratio of the alkyl sulfonium salt, the cotton fiber, and water is 0.5:6:100.

[0085] (7) Obtain sulfonium salt grafted antibacterial cotton fiber.

[0086] Example 4

[0087] The same parts as those of Example 2 are not repeated here. The difference lies in that in step (1), the polycarboxylic acid is succinic acid or tartaric acid, and the mass ratio of cotton fiber, water, succinic acid or tartaric acid, sodium phosphate, disodium hydrogen phosphate, and sodium hypophosphite is 6:100:15:0.5:0.8:5.

[0088] Example 5

[0089] The same parts as those of Example 2 are not repeated here. The difference lies in that: in step (1), the polycarboxylic acid is succinic acid or tartaric acid, and the mass ratio of cotton fiber, water, succinic acid or tartaric acid, sodium phosphate, disodium hydrogen phosphate, and sodium hypophosphite is 6:100:25:0.5:0.8:5.

[0090] Example 6

[0091] The same parts as those of Example 2 are not repeated here. The difference lies in that: in step (1), the polycarboxylic acid is succinic acid or tartaric acid, and the mass ratio of cotton fiber, water, succinic acid or tartaric acid, sodium phosphate, disodium hydrogen phosphate, and sodium hypophosphite is 6:100:30:0.5:0.8:5.

[0092] The present invention utilizes the sulfonium salt grafting modification method to obtain long-lasting antibacterial cotton fibers under different polycarboxylic acid and dosage conditions. The test results of grafting conditions, antibacterial properties, water washability, antibacterial properties, biosafety and mechanical properties are as follows:

[0093] 1. Grafting status, antibacterial property, water washability, antibacterial property, and biological safety:

[0094] Preparation process of alkyl sulfonium salt of the present invention

[0095] Prepare 20 mL of N,N-dimethylformamide / water solution with a volume ratio of 1:0.8, add 0.6 g of octadecyl sulfide and 1.8 mL of iodomethane, stir and react for 48 hours, then dialyze in 0.1 mol / L sodium chloride solution and deionized water for 24 hours, and finally freeze-dry for 48 hours to obtain alkyl sulfonium salt.

[0096] 1. Polycarboxylic acid is malic acid

[0097] (1) The mass ratio of cotton fiber, water, malic acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:10:0.5:0.8:5.

[0098] Disperse 18 g of cotton fiber in 300 g of pure water, dissolve 30 g of malic acid, 1.5 g of sodium phosphate, 2.4 g of disodium hydrogen phosphate, and 15 g of sodium hypophosphite in the water, and stir magnetically at 80 ° C for 1 hour. Then take out the fiber, rinse it three times, divide it into 3 parts, 6 g each, and transfer it to 100 g of pure water respectively. Adjust the pH to 10 with 0.1 mol / L sodium hydroxide solution, add 0.5 g of alkyl sulfonium salt respectively, and react with stirring at 50 ° C for 3 hours to obtain 10% malic acid-modified sulfonium salt grafted antibacterial cotton fiber.

[0099] EDX element analysis was performed on the surface of the antibacterial fiber, and the S element content (atomic%) was measured to be 0.56%, indicating that the alkyl sulfonium salt has been grafted on the surface of the cotton fiber. The antibacterial and water-washing resistance of the antibacterial cotton fiber modified by sulfonium salt grafting was tested according to FZ / T 73023-2006. At the same time, the antibacterial cotton fibers of the same batch were stored in a cool and ventilated place, and the antibacterial performance was tested after standing for 6 months and 12 months. The antibacterial rate is shown in Table 1. All samples showed water-washing resistance and long-lasting antibacterial effects, but the overall antibacterial effect was not good. According to GBT 16886.5-2017, the samples were tested for in vitro cytotoxicity, and the fibroblast survival rate was 99.8%, and the sample was non-cytotoxic.

[0100] Table 1 Antibacterial effect of 10% malic acid modified sulfonium salt grafted antibacterial cotton fiber

[0101] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 10% Malic Acid 67.8 68.0 62.7 10% Malic Acid - After 6 months 67.5 68.0 62.3 10% Malic Acid - After 12 months 66.2 67.2 61.6 10% Malic Acid - Wash 50 times 66,9 67.7 61.4 10% Malic Acid - Washed 100 times 65.1 66.5 60.3

[0102] (2) The mass ratio of cotton fiber, water, malic acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:15:0.5:0.8:5.

[0103] 30g malic acid was replaced with 45g malic acid to obtain 15% malic acid modified sulfonium salt grafted antibacterial cotton fiber. EDX element analysis and a series of antibacterial performance tests were performed on it. The S element content (atomic%) was measured to be 0.79%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was improved. The antibacterial rate is shown in Table 2. All samples showed water resistance and long-lasting antibacterial effect, but the overall antibacterial effect was poor. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.6%, and the samples were non-cytotoxic.

[0104] Table 2 Antibacterial effect of 15% malic acid modified sulfonium salt grafted antibacterial cotton fiber

[0105] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 15% Malic Acid 80.7 78.6 71.2 15% Malic Acid - After 6 months 80.0 78.1 70.7 15% Malic Acid - After 12 months 79.4 76.1 69.2 15% Malic Acid - Wash 50 times 79.8 77.7 70.9 15% Malic Acid - Washed 100 times 78.2 76.7 69.7

[0106] (3) The mass ratio of cotton fiber, water, malic acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:20:0.5:0.8:5.

[0107] 30g malic acid was replaced with 60g malic acid to obtain 20% malic acid modified sulfonium salt grafted antibacterial cotton fiber, which was subjected to EDX elemental analysis and a series of antibacterial performance tests. The S element content (atomic%) was measured to be 0.91%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was further improved. The antibacterial rate is shown in Table 3. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.7%, and the samples were non-cytotoxic.

[0108] Table 3 Antibacterial effect of 20% malic acid modified sulfonium salt grafted antibacterial cotton fiber

[0109] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 20% Malic Acid 90.5 91.5 87.5 20% Malic Acid - After 6 months 90.1 91.3 87.1 20% Malic Acid - After 12 months 89.1 90.2 86.2 20% malic acid-wash 50 times 90.4 91.4 87.4 20% Malic Acid - Washed 100 times 89.6 90.1 86.7

[0110] (4) The mass ratio of cotton fiber, water, malic acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:25:0.5:0.8:5.

[0111] 30g malic acid was replaced with 75g malic acid to obtain 25% malic acid-modified sulfonium salt grafted antibacterial cotton fiber. EDX element analysis and a series of antibacterial performance tests were performed on it. The S element content (atomic%) was measured to be 0.10%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was the highest in the malic acid-modified cotton fiber group. The antibacterial rate is shown in Table 4. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.5%, and the samples were non-cytotoxic.

[0112] Table 4 Antibacterial effect of 25% malic acid modified sulfonium salt grafted antibacterial cotton fiber

[0113]

[0114]

[0115] 2. The polycarboxylic acid is citric acid

[0116] (1) The mass ratio of cotton fiber, water, citric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:10:0.5:0.8:5.

[0117] Disperse 18 g of cotton fiber in 300 g of pure water, dissolve 30 g of citric acid, 1.5 g of sodium phosphate, 2.4 g of disodium hydrogen phosphate, and 15 g of sodium hypophosphite in the water, and stir magnetically at 80 ° C for 1 hour. Then take out the fiber, rinse it three times, divide it into 3 parts, 6 g each, and transfer it to 100 g of pure water respectively. Adjust the pH to 10 with 0.1 mol / L sodium hydroxide solution, add 0.5 g of alkyl sulfonium salt respectively, and react with stirring at 50 ° C for 3 hours to obtain 10% citric acid-modified sulfonium salt grafted antibacterial cotton fiber.

[0118] EDX element analysis was performed on the surface of the antibacterial fiber, and the S element content (atomic%) was measured to be 0.86%, indicating that the alkyl sulfonium salt has been grafted on the surface of the cotton fiber. The antibacterial and water-washing resistance of the antibacterial cotton fiber modified by sulfonium salt grafting was tested according to FZ / T 73023-2006. At the same time, the antibacterial cotton fibers of the same batch were stored in a cool and ventilated place, and the antibacterial performance was tested after standing for 6 months and 12 months. The antibacterial rate is shown in Table 5. All samples showed water-washing resistance and long-lasting antibacterial effects, but the overall antibacterial effect was not good. According to GBT 16886.5-2017, the samples were tested for in vitro cytotoxicity, and the fibroblast survival rate was 99.7%, and the samples were non-cytotoxic.

[0119] Table 5 Antibacterial effect of 10% citric acid modified sulfonium salt grafted antibacterial cotton fiber

[0120] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 10% citric acid 79.2 77.6 69.2 10% citric acid - after 6 months 79.2 77.2 68.3 10% citric acid - after 12 months 78.6 76.5 66.1 10% citric acid-water wash 50 times 78.5 77.4 68.8 10% citric acid-water wash 100 times 77.7 76.8 68.0

[0121] (2) The mass ratio of cotton fiber, water, citric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:15:0.5:0.8:5.

[0122] 30g of citric acid was replaced with 45g of citric acid to obtain 15% citric acid-modified sulfonium salt grafted antibacterial cotton fiber. EDX element analysis and a series of antibacterial performance tests were performed on it. The S element content (atomic%) was measured to be 0.95%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was improved. The antibacterial rate is shown in Table 6. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.5%, and the samples were non-cytotoxic.

[0123] Table 6 Antibacterial effect of 15% citric acid modified sulfonium salt grafted antibacterial cotton fiber

[0124]

[0125]

[0126] (3) The mass ratio of cotton fiber, water, citric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:20:0.5:0.8:5.

[0127] 30g of citric acid was replaced with 60g of citric acid to obtain 20% citric acid-modified sulfonium salt grafted antibacterial cotton fiber. EDX element analysis and a series of antibacterial performance tests were performed on it. The S element content (atomic%) was measured to be 1.13%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was further improved. The antibacterial rate is shown in Table 7. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.4%, and the samples were non-cytotoxic.

[0128] Table 7 Antibacterial effect of 20% citric acid modified sulfonium salt grafted antibacterial cotton fiber

[0129] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 20% citric acid ≥99.9 ≥99.9 ≥99.9 20% citric acid - after 6 months ≥99.9 ≥99.9 ≥99.9 20% citric acid - after 12 months ≥99.9 ≥99.9 ≥99.9 20% citric acid-water wash 50 times ≥99.9 ≥99.9 ≥99.9 20% citric acid-water wash 100 times ≥99.9 ≥99.9 ≥99.9

[0130] (4) The mass ratio of cotton fiber, water, citric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:25:0.5:0.8:5.

[0131] 30g of citric acid was replaced with 75g of citric acid to obtain 25% citric acid-modified sulfonium salt grafted antibacterial cotton fiber. EDX element analysis and a series of antibacterial performance tests were performed on it. The S element content (atomic%) was measured to be 1.32%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was the highest in the citric acid modified cotton fiber group. The antibacterial rate is shown in Table 8. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.6%, and the samples were non-cytotoxic.

[0132] Table 4 Antibacterial effect of 25% citric acid modified sulfonium salt grafted antibacterial cotton fiber

[0133] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 25% citric acid ≥99.9 ≥99.9 ≥99.9 25% citric acid - after 6 months ≥99.9 ≥99.9 ≥99.9 25% citric acid - after 12 months ≥99.9 ≥99.9 ≥99.9 25% citric acid-water wash 50 times ≥99.9 ≥99.9 ≥99.9 25% citric acid-water wash 100 times ≥99.9 ≥99.9 ≥99.9

[0134] 3. The polycarboxylic acid is succinic acid

[0135] (1) The mass ratio of cotton fiber, water, succinic acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:15:0.5:0.8:5.

[0136] Disperse 18 g of cotton fiber in 300 g of pure water, dissolve 45 g of succinic acid, 1.5 g of sodium phosphate, 2.4 g of disodium hydrogen phosphate, and 15 g of sodium hypophosphite in the water, and stir magnetically at 80 ° C for 1 hour. Then take out the fiber, rinse it three times, divide it into 3 parts, 6 g each, and transfer it to 100 g of pure water respectively. Adjust the pH to 10 with 0.1 mol / L sodium hydroxide solution, add 0.5 g of alkyl sulfonium salt respectively, and react with stirring at 50 ° C for 3 hours to obtain 15% succinic acid-modified sulfonium salt grafted antibacterial cotton fiber.

[0137] EDX element analysis was performed on the surface of the antibacterial fiber, and the S element content (atomic%) was measured to be 0.80%, indicating that the alkyl sulfonium salt has been grafted on the surface of the cotton fiber. The antibacterial and water-washing resistance of the antibacterial cotton fiber modified by sulfonium salt grafting was tested according to FZ / T 73023-2006. At the same time, the antibacterial cotton fibers of the same batch were stored in a cool and ventilated place, and the antibacterial performance was tested after standing for 6 months and 12 months. The antibacterial rate is shown in Table 9. All samples showed water-washing resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. According to GBT 16886.5-2017, the samples were tested for in vitro cytotoxicity, and the fibroblast survival rate was 99.5%, and the sample was non-cytotoxic.

[0138] Table 9 Antibacterial effect of 15% succinic acid modified sulfonium salt grafted antibacterial cotton fiber

[0139] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 15% Succinic Acid 81.6 84.7 70.5 15% Succinic Acid - After 6 months 80.8 84.6 70.4 15% Succinic Acid - After 12 months 80.1 83.8 69.5 15% succinic acid-washed 50 times 81.2 84.2 70.3 15% Succinic Acid - Washed 100 times 80.4 83.9 70.0

[0140] (2) The mass ratio of cotton fiber, water, succinic acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:20:0.5:0.8:5.

[0141] 45g of succinic acid was replaced with 60g of succinic acid to obtain 20% succinic acid-modified sulfonium salt grafted antibacterial cotton fiber. EDX element analysis and a series of antibacterial performance tests were performed on it. The S element content (atomic%) was measured to be 0.92%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was improved. The antibacterial rate is shown in Table 10. All samples showed water-resistant and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.7%, and the samples were non-cytotoxic.

[0142] Table 10 Antibacterial effect of 20% amber-modified sulfonium salt grafted antibacterial cotton fiber

[0143] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 20% Succinic Acid 93.2 91.5 88.6 20% Succinic Acid - After 6 months 92.6 92.6 86.4 20% Succinic Acid - After 12 months 92.1 90.2 87.2 20% succinic acid-washed 50 times 94.3 93.6 88.5 20% succinic acid-washed 100 times 92.8 93.5 88.3

[0144] (3) The mass ratio of cotton fiber, water, succinic acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:25:0.5:0.8:5.

[0145] 45g of succinic acid was replaced with 75g of succinic acid to obtain 25% succinic acid-modified sulfonium salt grafted antibacterial cotton fiber. EDX element analysis and a series of antibacterial performance tests were performed on it. The S element content (atomic%) was measured to be 1.11%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was further improved. The antibacterial rate is shown in Table 11. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.6%, and the samples were non-cytotoxic.

[0146] Table 11 Antibacterial effect of 25% succinic acid modified sulfonium salt grafted antibacterial cotton fiber

[0147] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 25% Succinic Acid ≥99.9 ≥99.9 ≥99.9 25% Succinic Acid - After 6 months ≥99.9 ≥99.9 ≥99.9 25% Succinic Acid - After 12 months ≥99.9 ≥99.9 ≥99.9 25% succinic acid-washed 50 times ≥99.9 ≥99.9 ≥99.9 25% Succinic Acid - Washed 100 times ≥99.9 ≥99.9 ≥99.9

[0148] (4) The mass ratio of cotton fiber, water, succinic acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:30:0.5:0.8:5.

[0149] 45g of succinic acid was replaced with 90g of succinic acid to obtain 30% succinic acid-modified sulfonium salt grafted antibacterial cotton fiber, which was subjected to EDX elemental analysis and a series of antibacterial performance tests. The S element content (atomic%) was measured to be 1.32%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was the highest in the succinic acid-modified cotton fiber group. The antibacterial rate is shown in Table 12. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.7%, and the samples were non-cytotoxic.

[0150] Table 12 Antibacterial effect of 30% succinic acid modified sulfonium salt grafted antibacterial cotton fiber

[0151] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 30% Succinic Acid ≥99.9 ≥99.9 ≥99.9 30% Succinic Acid - After 6 months ≥99.9 ≥99.9 ≥99.9 30% Succinic Acid - After 12 months ≥99.9 ≥99.9 ≥99.9 30% succinic acid-washed 50 times ≥99.9 ≥99.9 ≥99.9 30% succinic acid-washed 100 times ≥99.9 ≥99.9 ≥99.9

[0152] 4. The polycarboxylic acid is tartaric acid

[0153] (1) The mass ratio of cotton fiber, water, tartaric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:15:0.5:0.8:5.

[0154] Disperse 18 g of cotton fiber in 300 g of pure water, dissolve 45 g of tartaric acid, 1.5 g of sodium phosphate, 2.4 g of disodium hydrogen phosphate, and 15 g of sodium hypophosphite in the water, and stir magnetically at 80 ° C for 1 hour. Then take out the fiber, rinse it three times, divide it into 3 parts, 6 g each, and transfer it to 100 g of pure water respectively. Adjust the pH to 10 with 0.1 mol / L sodium hydroxide solution, add 0.5 g of alkyl sulfonium salt respectively, and react with stirring at 50 ° C for 3 hours to obtain 15% tartaric acid-modified sulfonium salt grafted antibacterial cotton fiber.

[0155] EDX element analysis was performed on the surface of the antibacterial fiber, and the S element content (atomic%) was measured to be 0.84%, indicating that the alkyl sulfonium salt has been grafted on the surface of the cotton fiber. The antibacterial and water-washing resistance of the antibacterial cotton fiber modified by sulfonium salt grafting was tested according to FZ / T 73023-2006. At the same time, the antibacterial cotton fibers of the same batch were stored in a cool and ventilated place, and the antibacterial performance was tested after standing for 6 months and 12 months. The antibacterial rate is shown in Table 13. All samples showed water-washing resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. According to GBT 16886.5-2017, the samples were tested for in vitro cytotoxicity, and the fibroblast survival rate was 99.7%, and the samples were non-cytotoxic.

[0156] Table 13 Antibacterial effect of 15% tartaric acid modified sulfonium salt grafted antibacterial cotton fiber

[0157] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 15% tartaric acid 83.5 82.8 72.5 15% Tartaric acid - after 6 months 82.3 82.3 71.3 15% Tartaric Acid - After 12 months 82.0 81.5 70.9 15% tartaric acid-wash 50 times 83.2 82.6 72.0 15% tartaric acid-washed 100 times 81.5 81.5 70.4

[0158] (2) The mass ratio of cotton fiber, water, tartaric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:20:0.5:0.8:5.

[0159] 45g of tartaric acid was replaced with 60g of tartaric acid to obtain 20% tartaric acid modified sulfonium salt grafted antibacterial cotton fiber, which was subjected to EDX elemental analysis and a series of antibacterial performance tests. The S element content (atomic%) was measured to be 0.96%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was improved. The antibacterial rate is shown in Table 14. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.5%, and the samples were non-cytotoxic.

[0160] Table 14 Antibacterial effect of 20% tartaric acid modified sulfonium salt grafted antibacterial cotton fiber

[0161] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 20% tartaric acid 94.7 93.9 91.6 20% Tartaric Acid - After 6 months 94.1 93.0 90.1 20% Tartaric Acid - After 12 months 92.9 92.5 89.6 20% tartaric acid-wash 50 times 93.7 92.6 90.7 20% tartaric acid-washed 100 times 92.4 92.0 89.2

[0162] (3) The mass ratio of cotton fiber, water, tartaric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:25:0.5:0.8:5.

[0163] 45g of tartaric acid was replaced with 75g of tartaric acid to obtain 25% tartaric acid-modified sulfonium salt grafted antibacterial cotton fiber, which was subjected to EDX elemental analysis and a series of antibacterial performance tests. The S element content (atomic%) was measured to be 1.12%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was further improved. The antibacterial rate is shown in Table 15. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.4%, and the samples were non-cytotoxic.

[0164] Table 15 Antibacterial effect of 25% tartaric acid modified sulfonium salt grafted antibacterial cotton fiber

[0165] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 25% tartaric acid ≥99.9 ≥99.9 ≥99.9 25% Tartaric Acid - After 6 months ≥99.9 ≥99.9 99.6 25% Tartaric Acid - After 12 months ≥99.9 ≥99.9 99.1 25% tartaric acid-wash 50 times ≥99.9 ≥99.9 99.4 25% tartaric acid-washed 100 times ≥99.9 ≥99.9 98.8

[0166] (4) The mass ratio of cotton fiber, water, tartaric acid, sodium phosphate, disodium hydrogen phosphate and sodium hypophosphite is 6:100:30:0.5:0.8:5.

[0167] 45g of tartaric acid was replaced with 90g of tartaric acid to obtain 30% tartaric acid-modified sulfonium salt grafted antibacterial cotton fiber, which was subjected to EDX elemental analysis and a series of antibacterial performance tests. The S element content (atomic%) was measured to be 1.33%, indicating that the alkyl sulfonium salt had been grafted on the surface of the cotton fiber, and the grafting rate was the highest in the tartaric acid modified cotton fiber group, and the antibacterial rate was shown in Table 16. All samples showed water resistance and long-lasting antibacterial effects, and the antibacterial level reached AAA. The samples were subjected to in vitro cytotoxicity tests, and the fibroblast survival rate was 99.5%, and the samples were non-cytotoxic.

[0168] Table 16 Antibacterial effect of 30% tartaric acid modified sulfonium salt grafted antibacterial cotton fiber

[0169] Antibacterial rate (%) Escherichia coli Staphylococcus aureus Candida albicans 30% tartaric acid ≥99.9 ≥99.9 ≥99.9 30% Tartaric Acid - After 6 months ≥99.9 ≥99.9 ≥99.9 30% Tartaric Acid - After 12 months ≥99.9 ≥99.9 ≥99.9 30% tartaric acid-washed 50 times ≥99.9 ≥99.9 ≥99.9 30% tartaric acid-washed 100 times ≥99.9 ≥99.9 ≥99.9

[0170] 2. Mechanical properties:

[0171] The surface morphologies of the sulfonium salt grafted antibacterial cotton fibers obtained after 25% malic acid modification, 25% citric acid modification, 30% succinic acid modification, and 30% tartaric acid modification are shown in Figure 2. Figure 2-5 As shown, all fibers maintain a smooth and continuous twisted structure, with no significant difference from natural cotton fibers. According to GB / T 13783-1992, the above four groups of modified sulfonium salt grafted antibacterial cotton fibers were tested for breaking strength, and the results are shown in Table 17.

[0172] Table 17 Breaking strength of ordinary cotton fiber and four kinds of antibacterial cotton fibers

[0173] Fiber status Average breaking strength (cN / tex) Average elongation at break (%) Ordinary cotton fiber 27.6 7.6 25% malic acid modified cotton fiber 26.5 7.2 25% citric acid modified cotton fiber 25.7 6.6 30% succinic acid modified cotton fiber 25.3 6.2 30% tartaric acid modified cotton fiber 25.5 6.5

[0174] From the above experimental results, it can be seen that by comparing the antibacterial rate, S element content, cell survival rate and electron microscope photos of cotton fibers obtained under different process parameters and treatment conditions in Table 1-16, it can be concluded that:

[0175] The sulfonium salt modified antibacterial cotton fiber provided by the present invention has excellent antibacterial properties and biosafety, and the antibacterial effect is not affected by time and washing. It can be seen from Table 17 that the surface morphology and mechanical properties of ordinary cotton fibers do not change significantly after antibacterial modification. This is because the alkyl sulfonium salt is only grafted with the side chain of the cellulose macromolecule, without destroying the main chain structure of the cellulose molecule, and the original characteristics of cellulose are retained to the greatest extent, that is, it still has a smooth surface morphology and high breaking strength. Through comparative analysis, in the pretreatment process of cotton fibers, the number of carboxyl groups and the carboxylic acid concentration in the polycarboxylic acid have a greater impact on the grafting process. Taking all factors into consideration, the sulfonium salt grafted antibacterial cotton fiber finally obtained by selecting the process conditions of Example 2 of the present invention and 25% malic acid\citric acid and 30% succinic acid\tartaric acid has the best comprehensive performance.

[0176] Since the grafting of alkyl sulfonium salts only occurs on the side chain groups of cellulose macromolecules and does not destroy the main chain of cellulose molecules, the main structural properties of cotton fibers are retained, and the fiber morphology structure and mechanical properties do not change significantly. At the same time, the positively charged sulfur in the grafted cellulose can adsorb negatively charged bacteria on the surface, and the long alkyl chains at both ends of the alkyl sulfonium salt can destroy the permeability of the bacterial cell membrane, thereby causing the bacteria to rupture and die, thereby achieving the antibacterial function. Because the carboxyl group and cellulose are combined through the newly generated ester bond, and the carboxyl group and the alkyl sulfonium salt are combined through electrostatic adsorption, it is difficult for physical actions such as friction and washing to destroy the chemical bond structure, so its antibacterial effect can remain stable and effective for a long time. By adopting the preparation method of the present invention, the fiber surface morphology before and after modification does not change significantly, the antibacterial effect is excellent, the water washing is resistant, and long-term antibacterial can be achieved; the biocompatibility is excellent, and no obvious toxic side effects are shown. The fiber obtained by esterification reaction and electrostatic adsorption has long-term and stable contact antibacterial performance, and at the same time shows good biological safety, and the process is simple and easy to operate, and batch production can be achieved.

[0177] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A method for preparing a long-lasting antibacterial cotton fiber modified by sulfonium salt grafting, characterized in that: The steps include:

1. Cotton fiber modification: (1) Mix polycarboxylic acid, sodium phosphate, disodium hydrogen phosphate, sodium hypophosphite and water to obtain a modified solution for later use; (2) taking a certain amount of cotton fiber and completely immersing and dispersing it in the modified solution, and reacting it with magnetic stirring at 40-100° C. for 0.5-5 h to obtain modified cotton fiber with carboxyl groups on the surface; 2. Preparation of alkyl sulfonium salts: (3) adding octadecyl thioether and methyl iodide to N,N-dimethylformamide / water solution and reacting for 24-48 hours to obtain a solution; (4) The resulting solution was dialyzed in a 0.1 mol / L sodium chloride solution for 24 h, and then dialyzed in deionized water for 24 h; (5) freeze-drying the dialyzed solution for 48 h to obtain an alkyl sulfonium salt; 3. Sulfonium salt grafted cotton fiber: (6) soaking the modified cotton fiber obtained in step (2) in an alkaline aqueous solution, adding the alkyl sulfonium salt obtained in step (5), and stirring the reaction at 40-80° C. for 1-4 h; (7) Obtain sulfonium salt grafted antibacterial cotton fiber.

2. The method for preparing the long-acting antibacterial cotton fiber grafted with sulfonium salt according to claim 1, characterized in that: In the step (1), the polycarboxylic acid is malic acid or citric acid, and the mass ratio of cotton fiber, water, malic acid or citric acid, sodium phosphate, disodium hydrogen phosphate, and sodium hypophosphite is 6:100:10-25:0.5:0.8:

5.

3. The method for preparing the long-acting antibacterial cotton fiber grafted with sulfonium salt according to claim 1, characterized in that: In the step (1), the polycarboxylic acid is succinic acid or tartaric acid, and the mass ratio of cotton fiber, water, succinic acid or tartaric acid, sodium phosphate, disodium hydrogen phosphate, and sodium hypophosphite is 6:100:15-30:0.5:0.8:

5.

4. The method for preparing the long-acting antibacterial cotton fiber grafted with sulfonium salt according to claim 1, characterized in that: In the step (2), the cotton fiber is reacted in the modified solution under magnetic stirring at 80° C. for 1 hour.

5. The method for preparing the long-acting antibacterial cotton fiber grafted with sulfonium salt according to claim 1, characterized in that: In the step (3), the mass ratio of octadecyl thioether to methyl iodide is 1:1-5, and the mass ratio of N,N-dimethylformamide / water solution is 1:0.5-1.

5.

6. The method for preparing the long-acting antibacterial cotton fiber grafted with sulfonium salt according to claim 1, characterized in that: In the step (6), the pH value of the alkaline aqueous solution is 9.5-10.5, and the mass ratio of the alkyl sulfonium salt, the cotton fiber, and the water is 0.5:6:

100.

7. The method for preparing the long-acting antibacterial cotton fiber grafted with sulfonium salt according to claim 1, characterized in that: In the step (6), the modified cotton fiber is immersed in an alkaline aqueous solution and stirred at 50° C. for 3 hours.

8. The method for preparing the long-acting antibacterial cotton fiber grafted with sulfonium salt according to claim 5, characterized in that: The mass ratio of the octadecyl thioether to methyl iodide is 1:3, and the ratio of the N,N-dimethylformamide to the aqueous solution is 1:0.

8.

9. The method for preparing the long-acting antibacterial cotton fiber grafted with sulfonium salt according to claim 6, characterized in that: In the step (6), the pH value of the alkaline aqueous solution is 10.

10. A long-lasting antibacterial cotton fiber grafted with sulfonium salt, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8.

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