Method for improving dyeing, water-repellent and antibacterial properties of cotton fibers through chemical modification

Abstract

The invention relates to a method for improving dyeing, water repellency and antibacterial properties of cotton fibers through chemical modification. According to the invention, epoxidized soybean oil molecules are used as bridges, epoxy groups in the epoxidized soybean oil are respectively subjected to ring-opening reaction with hydroxyl in cotton fibers and amino in polyhexamethylene guanidine hydrochloride, and polyhexamethylene guanidine hydrochloride molecules and cotton fiber molecules are chemically bonded, so that cationic modification of the cotton fibers is realized; therefore, the dye-uptake rate and fixation rate of salt-free dyeing of the reactive dye for the modified cotton fiber are improved, and the modified cotton fiber can be endowed with certain water-repellent and antibacterial properties on the basis of the dye-uptake rate and fixation rate.

Description

Technical Field

[0001] The invention belongs to the field of salt-free dyeing of cotton fabrics with reactive dyes. Background Art

[0002] Cotton fabrics have a high market share in the textile and garment industry and are closely related to people's lives. The use of cotton fabrics is inseparable from dyeing technology. Reactive dyes have become the most important type of dyes for dyeing cotton fiber textiles due to their complete color spectrum, bright color, excellent fastness and low cost. However, reactive dyes are anionic dyes, and a large amount of inorganic salts are usually added to promote dyeing during the traditional dyeing process. On the one hand, the addition of inorganic salts increases the production cost and pollution control cost. On the other hand, the discharge of a large amount of salt-containing dye wastewater will cause great harm to the ecological environment. Therefore, how to achieve low-salt or even salt-free dyeing of reactive dyes is the key to achieving green printing and dyeing production. After exploration and research by many scholars at home and abroad, it was found that cationic modification pretreatment of cotton fabrics can achieve salt-free dyeing of cotton fabrics with reactive dyes.

[0003] Cotton fibers are modified with cationic modification agents, and cationic groups are covalently bonded to the surface of cotton fibers through chemical reactions, which can change the negative potential on the surface of cotton fibers into positive potential, thereby enhancing the affinity of cotton fibers for reactive dyes. Cationic modification can greatly improve the dyeing rate and fixation rate of reactive dyes without salt, and the dyed cotton fabrics have high color fastness and levelness. However, the modification agents themselves may cause certain pollution to the environment, and the modification process will increase the process production flow, limiting the use of this method. Therefore, effectively combining the existing printing and dyeing production process and selecting green and safe cationic agents to modify cotton fabrics is an important prerequisite for realizing industrial production. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a green, safe, low-cost, multifunctional cotton fabric modification and salt-free dyeing method: the epoxy groups in the epoxidized soybean oil respectively undergo ring-opening reactions with the hydroxyl groups in the cotton fiber and the amino groups in the polyhexamethylene guanidine hydrochloride, and the polyhexamethylene guanidine hydrochloride and the cotton fiber are chemically bonded together using the epoxidized soybean oil as a bridge, thereby achieving cationic modification of the cotton fiber, thereby improving the dyeing rate and fixation rate of the reactive dye salt-free dyeing. Moreover, it is very important that the use of the epoxidized soybean oil can improve the hydrophobicity of the cotton fiber, and the covalent bonding of the polyhexamethylene guanidine hydrochloride can give the modified cotton fiber antibacterial properties.

[0005] To achieve the above purpose, the present invention discloses a method for improving the dyeing and water-repellent and antibacterial properties of cotton fibers by chemical modification. Before dyeing, the cotton fabric is modified, specifically, the cotton fabric is immersed in a modified aqueous solution composed of polyhexamethylene guanidine hydrochloride, epoxy soybean oil, hexadecyltrimethylammonium bromide and an emulsifier at room temperature, immersed twice and rolled twice, the rolling rate is 90-100%, reacted in an oven at 60-80°C for a certain time, and then washed with water and dried to obtain the modified cotton fabric.

[0006] The modified cotton fabric was dyed with reactive dyes under salt-free conditions. The dyeing conditions were as follows: dyeing in 4 g / L dye solution at room temperature for 30 min, slowly heating to 60 ℃, adding 20 g / L sodium carbonate, fixing for 60 min, washing with water, soaping with 2 g / L soap flake aqueous solution at 95 ℃ for 10 min, and drying after washing.

[0007] The beneficial effects of the present invention are: (1) The modified cotton fabric has a strong affinity for reactive dyes and can increase the reactive dye uptake to more than 89% under salt-free conditions.

[0008] (2) Epoxidized soybean oil and polyhexamethylene biguanide hydrochloride respectively endowed the modified cotton fabric with certain water repellent and antibacterial properties. The water contact angle of the modified cotton fiber can reach 139.2°.

[0009] (3) The modification reagent involved in the present invention is green and non-toxic, the modification process is clean and simple, and has high practicality. Implementation Example

[0010] (1) Cotton fabric modification process The cotton fiber was immersed in a modified aqueous solution composed of polyhexamethylene guanidine hydrochloride, epoxidized soybean oil, hexadecyl trimethyl ammonium bromide, and octylphenol polyoxyethylene ether at room temperature, wherein the concentration of polyhexamethylene guanidine hydrochloride was 4g / L, the concentration of epoxidized soybean oil was 2g / L, the concentration of hexadecyl trimethyl ammonium bromide was 0.2g / L, the concentration of octylphenol polyoxyethylene ether was 1g / L, and the pH value of the modified aqueous solution was 13. Two immersions and two rollings were performed, and the rolling rate was 90%. The modified cotton fiber was then placed in an oven for reaction, the oven temperature was 70°C, the baking time was 60 minutes, and it was washed and dried.

[0011] (2) Salt-free dyeing process of modified cotton fabric Reactive black KN-B, dosage is 4% (mass percentage, based on cotton fiber weight), bath ratio is 1:30, dyeing at 25 ℃ for 30 min, slowly heating to 60 ℃, adding 20 g / L sodium carbonate, fixing for 60 min, washing with water, soap washing with 2 g / L soap flake aqueous solution at 95 ℃ for 10 min, washing with water and drying.

[0012] (3) Dyeing process of unmodified cotton fabric Reactive black KN-B, dosage is 4% (mass percentage, based on cotton fiber weight), bath ratio is 1:30, sodium chloride dosage is 60 g / L, dyeing at 25 ℃ for 30 min, slowly heat to 60 ℃, add 20 g / L sodium carbonate, fix color for 60 min, wash with water, soap wash with 2 g / L soap flake aqueous solution at 95 ℃ for 10 min, wash with water and dry.

[0013] (4) Antibacterial properties of cotton fabrics LB culture medium was prepared and coated with Escherichia coli liquid. The modified and unmodified cotton fabrics were sterilized at high temperature and placed in the center of the culture medium with sterile tweezers. They were pressed evenly to make full contact between the fabric and the culture medium. The plate was then inverted in a biochemical incubator and cultured at a constant temperature for 24 h. The width of the inhibition zone around the cotton fabric on the culture medium was measured to compare the antibacterial properties.

[0014] (5) Water repellency of cotton fabrics The water contact angle test was conducted on the original cotton fabric and the modified cotton fabric. The test instrument was a surface tension meter, model: Dataphysics DCAT21. The test fabric samples were cut into long strips and fixed with a clamp. The contact angle values ​​of multiple positions of each sample were tested. The image captured by the camera was cut at the intersection of the sample surface and the droplet in the image, and intersected with the horizontal plane of the sample. The angle formed was automatically calculated by the computer, which was the contact angle.

[0015] The relevant experimental results are shown in Tables 1 and 2. Example

[0016] (1) Cotton fabric modification process The cotton fiber was immersed in a modified aqueous solution composed of polyhexamethylene guanidine hydrochloride, epoxidized soybean oil, hexadecyl trimethyl ammonium bromide, and octylphenol polyoxyethylene ether at room temperature, wherein the concentration of polyhexamethylene guanidine hydrochloride was 5g / L, the concentration of epoxidized soybean oil was 2g / L, the concentration of hexadecyl trimethyl ammonium bromide was 0.15g / L, the concentration of octylphenol polyoxyethylene ether was 1g / L, and the pH value of the modified aqueous solution was 14. Two immersions and two rollings, the rolling rate was 100%. Then the modified cotton fiber was placed in an oven for reaction, the oven temperature was 70℃, the baking time was 60 minutes, and it was washed and dried.

[0017] (2) Dyeing process of modified cotton fabric Reactive Red 3BSN, dosage is 4% (mass percentage, based on cotton fiber weight), bath ratio is 1:30, dyeing at 25 ℃ for 30 min, slowly heat to 60 ℃, add 20 g / L sodium carbonate, fix for 60 min, wash with water, soap wash with 2 g / L soap flake aqueous solution at 95 ℃ for 10 min, and dry after washing.

[0018] (3) Dyeing process of unmodified cotton fabric Reactive Red 3BSN, dosage is 4% (mass percentage, based on cotton fiber weight), bath ratio is 1:30, sodium chloride dosage is 60 g / L, dyeing at 25 ℃ for 30 min, slowly heat to 60 ℃, add 20 g / L sodium carbonate, fix for 60 min, wash with water, soap wash with 2 g / L soap flake aqueous solution at 95 ℃ for 10 min, and dry after washing.

[0019] (4) Antibacterial properties of cotton fabrics LB culture medium was prepared and coated with Staphylococcus aureus liquid. The modified and unmodified cotton fabrics were sterilized at high temperature and placed in the center of the culture medium with sterile tweezers. They were pressed evenly to make full contact between the fabric and the culture medium. The plate was then inverted in a biochemical incubator and cultured at a constant temperature for 24 h. The width of the inhibition zone around the cotton fabric on the culture medium was measured to compare the antibacterial properties.

[0020] (5) Water repellency of cotton fabrics The water contact angle test was conducted on the original cotton fabric and the modified cotton fabric. The test instrument was a surface tension meter, model: Dataphysics DCAT21. The test fabric samples were cut into long strips and fixed with a clamp. The contact angle values ​​of multiple positions of each sample were tested. The image captured by the camera was cut at the intersection of the sample surface and the droplet in the image, and intersected with the horizontal plane of the sample. The angle formed was automatically calculated by the computer, which was the contact angle.

[0021] The relevant experimental results are shown in Tables 1 and 2. Example

[0022] (1) Cotton fabric modification process The cotton fiber was immersed in a modified aqueous solution composed of polyhexamethylene guanidine hydrochloride, epoxidized soybean oil, hexadecyl trimethyl ammonium bromide, and octylphenol polyoxyethylene ether at room temperature, wherein the concentration of polyhexamethylene guanidine hydrochloride was 3g / L, the concentration of epoxidized soybean oil was 1.5g / L, the concentration of hexadecyl trimethyl ammonium bromide was 0.3g / L, the concentration of octylphenol polyoxyethylene ether was 1.5g / L, and the pH value of the modified aqueous solution was 12. Two immersions and two rollings, the rolling rate was 90%. Then the modified cotton fiber was placed in an oven for reaction, the oven temperature was 70°C, the baking time was 60 minutes, and it was washed and dried.

[0023] (2) Dyeing process of modified cotton fabric Reactive Yellow 3RS, dosage is 4% (mass percentage, based on cotton fiber weight), bath ratio is 1:30, dye at 25 ℃ for 30 min, slowly heat to 60 ℃, add 20 g / L sodium carbonate, fix for 60 min, wash with water, soap wash with 2 g / L soap flake aqueous solution at 95 ℃ for 10 min, wash with water and dry.

[0024] (3) Dyeing process of unmodified cotton fabric Reactive Yellow 3RS, dosage is 4% (mass percentage, based on cotton fiber weight), bath ratio is 1:30, sodium chloride dosage is 60 g / L, dyeing at 25 ℃ for 30 min, slowly heat to 60 ℃, add 20 g / L sodium carbonate, fix for 60 min, wash with water, soap wash with 2 g / L soap flake aqueous solution at 95 ℃ for 10 min, wash with water and dry.

[0025] (4) Antibacterial properties of cotton fabrics LB culture medium was prepared and coated with Escherichia coli liquid. The modified and unmodified cotton fabrics were sterilized at high temperature and placed in the center of the culture medium with sterile tweezers. They were pressed evenly to make full contact between the fabric and the culture medium. The plate was then inverted in a biochemical incubator and cultured at a constant temperature for 24 h. The width of the inhibition zone around the cotton fabric on the culture medium was measured to compare the antibacterial properties.

[0026] (5) Water repellency of cotton fabrics The water contact angle test was conducted on the original cotton fabric and the modified cotton fabric. The test instrument was a surface tension meter, model: Dataphysics DCAT21. The test fabric samples were cut into long strips and fixed with a clamp. The contact angle values ​​of multiple positions of each sample were tested. The image captured by the camera was cut at the intersection of the sample surface and the droplet in the image, and intersected with the horizontal plane of the sample. The angle formed was automatically calculated by the computer, which was the contact angle.

[0027] The relevant experimental results are shown in Tables 1 and 2.

[0028] Table 1 and Table 2 are comparison tables of reactive dyeing performance and antibacterial and water repellent performance of modified and unmodified cotton fabrics, respectively. The total utilization rate of dyes T and K / S value are calculated as follows:

[0029] In the formula, A0, A1, A2 are λ max The absorbance of the dye solution before and after dyeing and after soaping measured by UV-2600 ultraviolet-visible spectrophotometer; R is λ max The reflectance of the fabric was measured using a Ci6X spectrophotometer.

[0030]

[0031]

[0032] After testing, the cotton fiber treated by the technical solution of this embodiment has higher salt-free dyeing utilization rate and antibacterial water repellency than unmodified cotton fabric. The cotton fabric chemically modified by epoxy soybean oil and polyhexamethylene guanidine hydrochloride is cationized and can be dyed with reactive dyes without salt. The dyeing rate is increased by about 40% compared with the traditional dyeing method, and has good color fastness. The modified cotton fiber also has good water repellency and shows good antibacterial performance against different bacteria. It is a multifunctional modified cotton fiber.

Claims

1. A method for improving the dyeing and water-repellent and antibacterial properties of cotton fibers by chemical modification, characterized in that: The cotton fiber is modified before dyeing, specifically, the cotton fiber is immersed in a modified aqueous solution composed of polyhexamethylene guanidine hydrochloride, epoxy soybean oil, hexadecyltrimethylammonium bromide and an emulsifier at room temperature, immersed twice and rolled twice, baked for a certain period of time, washed with water and dried to obtain a modified cotton fabric.

2. A method for improving the dyeing and water-repellent and antibacterial properties of cotton fibers by chemical modification according to claim 1, characterized in that The concentration of polyhexamethylene guanidine hydrochloride in the modified aqueous solution is 3-5 g / L, the concentration of epoxidized soybean oil is 1-3 g / L, the concentration of hexadecyltrimethylammonium bromide is 0.1-0.3 g / L, the emulsifier is octylphenol polyoxyethylene ether, the concentration is 0.5-1.5 g / L, and the pH value of the modified aqueous solution is 12-14.

3. A method for improving the dyeing and water-repellent and antibacterial properties of cotton fibers by chemical modification according to claim 1, characterized in that The baking temperature is 60° C. to 80° C., and the baking time is 60 minutes.

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