A method for the enzymatic stripping of indigo denim

Abstract

The application discloses an enzyme washing and decoloring method of indigo denim, and belongs to the field of denim washing and decoloring. The application utilizes a catalytic system of horseradish peroxidase / H2O2, optimizes the formula of a working solution through screening, and improves the decoloring efficiency of denim based on the synergistic effect of H2O2, horseradish peroxidase, acetic acid and acetate in a specific ratio, so that the purpose of efficient decoloring and reducing fabric damage is achieved. After the denim is treated by the method, the following can be simultaneously achieved: high decoloring rate, low strength damage, short treatment process, simple equipment, convenient operation, high production efficiency, and the method can be applied to industrialized production and processing.

Description

Technical Field

[0001] This invention relates to an enzyme washing and decolorization method for indigo denim, belonging to the field of denim washing and decolorization. Background Technology

[0002] Denim fabric is loved by consumers of all levels for its unique appearance and durable performance. Through proper finishing, some dyes are removed, and the denim fabric is evenly or locally faded, giving it a rich and colorful style. Therefore, the finishing of denim fabric is particularly important.

[0003] Traditional physical bleaching methods, such as stone milling, can severely damage the fabric and even cause it to break. Common chemical bleaching methods mainly use strong oxidants or bleaching agents to destroy the indigo dye, causing the fabric to fade. Fabrics treated with these methods are prone to yellowing and becoming brittle, which can seriously affect the performance of denim. Enzyme washing can effectively avoid these problems. Common water washing bleaching processes mainly use cellulase, laccase, and other enzymes for bleaching.

[0004] Cellulase can cause the surface cellulose of denim fabric to detach under certain conditions, and the indigo dye attached to the detached fibers will also be peeled off. However, some of the detached dye will deposit and adhere to the fabric surface, making it prone to re-staining after cellulase treatment, and cellulase can also damage the fabric. Laccase mainly acts on indigo in the aqueous phase, decomposing the indigo that has detached into the aqueous phase and preventing the indigo in the aqueous phase from re-staining onto the denim. When laccase is used alone on denim, the stripping and polishing effects are relatively poor. Therefore, laccase is mostly used to treat indigo dye in wastewater and is rarely used alone for denim decolorization. Summary of the Invention

[0005] [Technical Issues]

[0006] Existing enzyme washing and finishing processes have low decolorization efficiency, and the treated denim is prone to re-staining. In particular, the strength of denim treated with acid cellulase is damaged, affecting the wearability of the denim.

[0007] [Technical Solution]

[0008] To address the problems of low bleaching efficiency and poor bleaching effect in existing indigo-dyed denim, this invention provides an energy-saving and environmentally friendly bleaching method. Specifically, it utilizes a horseradish peroxidase / H2O2 bleaching system. The indigo-dyed denim is immersed in a buffer solution containing the horseradish peroxidase / H2O2 bleaching system at a pH of 5-7. After sufficient reaction, the denim is removed, washed, and dried, achieving a better bleaching rate and lower strength damage.

[0009] The first objective of this invention is to provide an enzymatic decolorization method for indigo denim, comprising the following steps:

[0010] First, soak the indigo denim in a buffer solution with a pH of 5-7, then add horseradish peroxidase. After it dissolves, add H2O2 solution and mix well to obtain a mixture.

[0011] The mixture is then heated and kept warm to remove the color. After the color removal is complete, it is washed and dried to obtain the decolorized denim.

[0012] In one embodiment of the present invention, the bath ratio (mass ratio) of the indigo denim and the buffer solution is 1:10 to 40.

[0013] In one embodiment of the present invention, the buffer solution with a pH of 5-7 is composed of acetic acid, acetate, and a permeabilizer, or is composed of sodium dihydrogen phosphate and sodium bicarbonate; wherein the mass ratio of acetic acid, acetate, and permeabilizer is (7-15):(3-9):1; and the permeabilizer is permeabilizer JFC.

[0014] In one embodiment of the present invention, the amount of horseradish peroxidase added is 1-10% (owf); the enzyme activity is 30-60 U / mg.

[0015] In one embodiment of the present invention, the horseradish peroxidase is dissolved by stirring for 1 to 10 minutes.

[0016] In one embodiment of the present invention, the H2O2 solution is an aqueous solution of H2O2 with a mass fraction of 30% and a concentration of 1 to 5 mL / L.

[0017] In one embodiment of the present invention, the decolorization is carried out by heating to 20-50°C at a heating rate of 0.5-3°C / min, and holding the temperature at a shaking rate of 60-120 r / min for 60-80 min.

[0018] The second objective of this invention is to prepare the decolorized denim fabric obtained by the method described in this invention.

[0019] The third objective of this invention is the application of the decolorization method described herein in the textile field.

[0020] [Beneficial Effects]

[0021] This invention provides an enzymatic decolorization method for indigo-dyed denim. Utilizing a horseradish peroxidase / H2O2 catalytic system, the indigo dye is decomposed into small-molecule colorless substances such as aniline, benzoic acid, and toluene, achieving decolorization. By screening and optimizing the working solution formulation, based on the synergistic effect of specific proportions of H2O2, horseradish peroxidase, acetic acid, and acetate on the denim, the decolorization efficiency of the denim is improved, achieving high-efficiency decolorization and reducing fabric damage. Denim treated by this method simultaneously achieves: high decolorization rate, low strength loss, short processing flow, simple equipment, convenient operation, and high production efficiency, making it applicable to industrial production and processing.

[0022] Specifically:

[0023] (1) High decolorization rate and low strength damage: Different decolorization effects can be achieved by controlling the decolorization conditions. The decolorization rate can reach more than 80%, and the strength retention rate of the denim after treatment is 97.9%, with little strength loss, which is significantly better than other enzyme washing and finishing methods.

[0024] (2) Short processing flow and convenient operation: Compared with traditional chemical agents, such as sodium hypochlorite and bleaching powder, the decolorization method described in this invention does not require a high temperature, only 20-50℃, and has low equipment requirements and low energy consumption.

[0025] (3) Economic benefits: The decolorization method used in this invention involves fewer chemical reagents and produces very low environmental pollution, which is in line with the concept of environmental protection. At the same time, the process is simple and reliable, has low equipment requirements, and is easy to realize industrial production. Detailed Implementation

[0026] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0027] Test method:

[0028] 1. Method for determining decolorization rate:

[0029] The K / S values ​​before and after decolorization were measured using a Datacolor colorimeter, and the decolorization rate was calculated using formula (1).

[0030]

[0031] In equation (1), K / S u K / S value of unbleached fabric; K / S t This represents the K / S value of the fabric after bleaching treatment.

[0032] 2. Test of strong retention rate:

[0033] The breaking strength of the fabric before and after decolorization was measured using a YG065 electronic fabric strength tester, and the strength retention rate was calculated using formula (2).

[0034]

[0035] Where Fu is the strength of the fabric without bleaching treatment, and Ft is the strength of the fabric after bleaching treatment.

[0036] Raw materials used in the examples and comparative examples:

[0037] Indigo denim (untreated): 20cm x 30cm; purchased from Heibudan Textile Co., Ltd., weight 374g / m². 2 ; 236×170 (warp density×weft density, root / 10cm); its K / S value was 7.44 as measured by a Datacolor colorimeter;

[0038] Horseradish peroxidase activity was 30–60 U / mg; purchased from Novozymes;

[0039] The H2O2 solution is a 30% (w / w) aqueous solution of H2O2.

[0040] The cellulase activity was 50,000 U / mg; purchased from Novozymes.

[0041] The enzyme activity of laccase was 20,000 U / mg; it was purchased from Novozymes.

[0042] Example 1

[0043] An enzyme-based decolorization method for indigo denim includes the following steps:

[0044] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then horseradish peroxidase with a concentration of 1% (owf) was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 1.5mL / L. The mixture was mixed evenly to obtain a mixture.

[0045] The mixture was then heated to 25°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0046] Example 2

[0047] An enzyme-based decolorization method for indigo denim includes the following steps:

[0048] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then 3% (owf) horseradish peroxidase was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 1.5 mL / L. The mixture was mixed evenly to obtain a mixture.

[0049] The mixture was then heated to 25°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0050] Example 3

[0051] An enzyme-based decolorization method for indigo denim includes the following steps:

[0052] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then horseradish peroxidase with a concentration of 3% (owf) was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 1 mL / L. The mixture was mixed evenly to obtain a mixture.

[0053] The mixture was then heated to 25°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0054] Example 4

[0055] An enzyme-based decolorization method for indigo denim includes the following steps:

[0056] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then 3% (owf) horseradish peroxidase was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2 mL / L. The mixture was then mixed evenly to obtain a mixture.

[0057] The mixture was then heated to 25°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0058] Example 5

[0059] An enzyme-based decolorization method for indigo denim includes the following steps:

[0060] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then horseradish peroxidase with a concentration of 3% (owf) was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2.5mL / L. The mixture was mixed evenly to obtain a mixture.

[0061] The mixture was then heated to 25°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0062] Example 6

[0063] An enzyme-based decolorization method for indigo denim includes the following steps:

[0064] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then 3% (owf) horseradish peroxidase was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 3 mL / L. The mixture was mixed evenly to obtain a mixture.

[0065] The mixture was then heated to 25°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0066] Example 7

[0067] An enzyme-based decolorization method for indigo denim includes the following steps:

[0068] According to the bath ratio of 1:20, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then horseradish peroxidase with a concentration of 3% (owf) was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2.5mL / L. The mixture was mixed evenly to obtain a mixture.

[0069] The mixture was then heated to 25°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0070] Example 8

[0071] An enzyme-based decolorization method for indigo denim includes the following steps:

[0072] According to the bath ratio of 1:30, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then 3% (owf) horseradish peroxidase was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2.5 mL / L. The mixture was mixed evenly to obtain a mixture.

[0073] The mixture was then heated to 25°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0074] Example 9

[0075] An enzyme-based decolorization method for indigo denim includes the following steps:

[0076] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then horseradish peroxidase with a concentration of 3% (owf) was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2.5mL / L. The mixture was mixed evenly to obtain a mixture.

[0077] The mixture was then heated to 35°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0078] Example 10

[0079] An enzyme-based decolorization method for indigo denim includes the following steps:

[0080] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 10:5:1), and then horseradish peroxidase with a concentration of 3% (owf) was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2.5mL / L. The mixture was mixed evenly to obtain a mixture.

[0081] The mixture was then heated to 45°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0082] Example 11

[0083] An enzyme-based decolorization method for indigo denim includes the following steps:

[0084] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with pH 3 (composed of acetic acid, sodium acetate and penetrant JFC in a mass ratio of 14:9:2), and then horseradish peroxidase with a concentration of 3% (owf) was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2.5mL / L. The mixture was mixed evenly to obtain a mixture.

[0085] The mixture was then heated to 35°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0086] Example 12

[0087] An enzyme-based decolorization method for indigo denim includes the following steps:

[0088] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with pH 4 (composed of acetic acid, sodium acetate and penetrant JFC in a mass ratio of 7:4:1), and then 3% (owf) horseradish peroxidase was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2.5mL / L. The mixture was mixed evenly to obtain a mixture.

[0089] The mixture was then heated to 35°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0090] Example 13

[0091] An enzyme-based decolorization method for indigo denim includes the following steps:

[0092] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with pH 5 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 7:3:1), and then 3% (owf) horseradish peroxidase was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2.5 mL / L. The mixture was then mixed evenly to obtain a mixture.

[0093] The mixture was then heated to 35°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0094] Example 14

[0095] An enzyme-based decolorization method for indigo denim includes the following steps:

[0096] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with pH 6 (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 7:2:1), and then 3% (owf) horseradish peroxidase was added. After stirring for 5 minutes to dissolve, H2O2 solution was added to make the concentration of H2O2 solution 2.5 mL / L. The mixture was mixed evenly to obtain a mixture.

[0097] The mixture was then heated to 35°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0098] Comparative Example 1

[0099] Horseradish peroxidase and H2O2 solution were omitted in Example 13, while other aspects remained the same as in Example 13, resulting in decolorized denim fabric.

[0100] Comparative Example 2

[0101] Horseradish peroxidase in Example 13 was omitted, while everything else remained the same as in Example 13, resulting in decolorized denim.

[0102] Comparative Example 3 with Acetylacetone

[0103] Based on Example 13, acetylacetone was added as follows:

[0104] According to the bath ratio of 1:10, indigo denim fabric was immersed in a pH 5 buffer solution (composed of acetic acid, sodium acetate, and penetrant JFC in a mass ratio of 7:3:1), then 3% (owf) horseradish peroxidase was added, and the mixture was stirred for 5 minutes until dissolved. H2O2 solution was then added to make the concentration of H2O2 solution 2.5 mL / L, and the mixture was stirred evenly. Then acetylacetone was added to make its mass concentration in the mixture 3%, and the mixture was stirred evenly to obtain the final mixture.

[0105] The mixture was then heated to 35°C at a rate of 2°C / min, and then placed in a water bath shaker at 120r / min for 70min for decolorization. After decolorization, the mixture was washed and dried to obtain the decolorized denim fabric.

[0106] The specific parameter design and test results of the embodiments and comparative examples are compared in Table 1:

[0107] Table 1. Specific parameter design and test results for the embodiments and comparative examples.

[0108]

[0109] Comparative Example 4: Cellulase Washing

[0110] An enzyme-based decolorization method for indigo denim includes the following steps:

[0111] According to the bath ratio of 1:15, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate and penetrant JFC in a mass ratio of 10:5:1), and then 3% (owf) of cellulase was added. The mixture was stirred for 5 minutes and mixed evenly to obtain a mixture.

[0112] The mixture was then heated to 60°C at a rate of 2°C / min, and then placed in a high-temperature and high-pressure dyeing machine at 35r / min for 60min to remove the color. After the color removal was completed, the mixture was washed and dried to obtain the decolorized denim fabric.

[0113] The resulting decolorized denim fabric underwent performance testing, and the results are as follows:

[0114] The bleaching rate was 11.1%, and the strength retention rate was 85.5%. This method causes strength damage to the fabric, resulting in a significant decrease in fabric strength.

[0115] Comparative Example 5: Laccase Wash

[0116] An enzyme-based decolorization method for indigo denim includes the following steps:

[0117] According to the bath ratio of 1:10, the indigo denim fabric was immersed in a buffer solution with a pH of 4.5 (composed of acetic acid, sodium acetate and penetrant JFC in a mass ratio of 10:5:1), and then laccase with a concentration of 3% (owf) was added. The mixture was stirred for 5 minutes and mixed evenly to obtain a mixture.

[0118] The mixture was then heated to 70°C at a rate of 2°C / min, and then placed in a high-temperature and high-pressure dyeing machine at 35r / min for 60 minutes to remove the color. After the color removal was completed, the mixture was washed and dried to obtain the decolorized denim fabric.

[0119] The resulting decolorized denim fabric underwent performance testing, and the results are as follows:

[0120] The bleaching rate was 3.4%, and the strength retention rate was 98.7%. This method has a moderate bleaching effect on fabrics, with minimal damage to strength and no significant decrease in fabric strength.

[0121] In summary, this invention provides an enzymatic decolorization method for indigo-dyed denim fabrics. This invention uses fewer chemical auxiliaries and provides a corresponding decolorization method. Denim fabrics treated with this method show significant decolorization effects, achieving a decolorization rate of up to 80%, while maintaining a high strength retention rate, thus meeting the decolorization finishing requirements for denim fabrics.

[0122] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for enzymatically washing and decolorizing indigo denim, characterized in that, Includes the following steps: First, immerse the indigo denim in a buffer solution composed of acetic acid, sodium acetate, and penetrant JFC. Then, add horseradish peroxidase at a concentration of 3% owf and an enzyme activity of 30-60 U / mg. Stir for 5 minutes until dissolved, then add H2O2 solution (30% by mass, 2.5 mL / L). Mix thoroughly to obtain the final mixture. The mixture is then heated and kept warm to remove the color. After the color removal is complete, it is washed and dried to obtain the decolorized denim. in, The mass ratio of acetic acid, sodium acetate, and penetrant is 10:5:1; the pH of the buffer solution is 4.5; the bath ratio of indigo denim to buffer solution is 1:10, 1:20, or 1:30; the heating rate is 2℃ / min; the temperature is raised to 25℃; and the temperature is maintained at 120 r / min for 70 min. or, The mass ratio of acetic acid, sodium acetate, and penetrant was 7:4:1; the pH of the buffer solution was 4; the bath ratio of indigo denim to the buffer solution was 1:10; the heating rate was 2℃ / min; the temperature was raised to 35℃; and the temperature was maintained at 120 r / min for 70 min. or, The mass ratio of acetic acid, sodium acetate, and penetrant was 7:3:1; the pH of the buffer solution was 5; the bath ratio of indigo denim to the buffer solution was 1:10; the heating rate was 2℃ / min; the temperature was raised to 35℃; and the temperature was maintained at 120 r / min for 70 min. The mass ratio of acetic acid, sodium acetate, and penetrant was 7:2:1; the pH of the buffer solution was 6; the bath ratio of indigo denim to the buffer solution was 1:10; the heating rate was 2℃ / min; the temperature was raised to 35℃; and the temperature was maintained at 120 r / min for 70 min.

2. The decolorized denim fabric prepared by the method of claim 1.

3. The application of the method of claim 1 in the textile field.

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