Preparation method of novel environment-friendly chlorine-resistant color fixing agent

Abstract

The invention discloses a preparation method of a novel environment-friendly chlorine-resistant color fixing agent, which comprises the following steps: 1) preparing an intermediate: adding polyethylene glycol into a reaction bottle, dehydrating for 1 hour at 120 DEG C under the relative vacuum degree of-0.1 MP, cooling to below 60 DEG C, adding TD I and a solvent, carrying out heat preservation reaction for 1 hour at 60-65 DEG C, and cooling to obtain a polyurethane prepolymer; wherein TDI (toluene diisocyanate) is a mixture of 80% of toluene-2, 4-diisocyanate and 20% of toluene-2, 6-diisocyanate; (2) slowly dropwise adding the polyurethane prepolymer in the step (1) into polyethyleneimine, controlling the temperature to be lower than 40 DEG C during the period, then adding an end-capping reagent, carrying out heat preservation reaction for 1 hour, and adding water to prepare an intermediate product; 2) preparing an environment-friendly chlorine-resistant color fixing agent: adding the intermediate in the step 1) into a reaction bottle, stirring, slowly dropwise adding a cationic etherifying agent, and controlling the temperature to be 20-40 DEG C; and after dripping, carrying out heat preservation reaction for 3-5 hours, controlling the temperature at 60-80 DEG C, finally adjusting the pH value to 5-7 by using glacial acetic acid, and cooling to obtain the environment-friendly chlorine-resistant color fixing agent. The color fixing agent has good chlorine-resistant color fastness and color fixing effect.

Description

Technical Field

[0001] This invention relates to the field of dyeing and finishing technology, and in particular to a method for preparing and applying a novel environmentally friendly chlorine-resistant color-fixing agent. Background Technology

[0002] Reactive dyes possess excellent colorfastness, vibrant colors, a wide color chromatogram, and simple application processes, making them widely used in the printing and dyeing industry. Especially in recent years, significant progress has been made in the improvement of reactive dye varieties, quality enhancement, and the adoption of novel application technologies. They are increasingly replacing other types of dyes in many fields, covering a wide range of fabrics including cotton, wool, silk, knitwear, and bedding. However, the chlorine fastness of fabrics dyed with reactive dyes is generally poor, making it difficult for some shades of dyed fabrics to meet the chlorine fastness requirements for textiles.

[0003] Chlorine in tap water is the primary cause of color changes and even fading in dyed fabrics. Besides oxidative bleaching, chlorine can also undergo chlorination reactions. Even small amounts of chlorine present during fabric washing can oxidize and destroy dye molecules containing groups with poor chlorine resistance (such as -N=), ultimately leading to fading. It is generally believed that chlorine reacts with the dye matrix or bridging groups, altering or even destroying the chromophores or auxochromes, or breaking the covalent bonds between the dye and the fiber, resulting in poorer chlorine fastness of the dyed fabric. The fading of dyes containing azo groups by chlorine bleaching is mainly due to the dissociation reaction of the azo tautomer. Dyes with hydroxyl groups at the ortho or para positions of the azo group undergo proton transfer, producing an azo-quinone hydrazone tautomerism. The easier it is for the -NH-N= group in the dye structure to dissociate, the more susceptible it is to fading due to chlorine.

[0004] In summary, reactive chlorine substances can undergo oxidation reactions with certain dye molecules, leading to the destruction of the dye molecular structure and resulting in problems such as color fading and discoloration, severely affecting the color retention and service life of cotton fabrics. Therefore, textiles such as swimwear and those used in applications involving contact with reactive chlorine substances require chlorine-resistant finishing to improve their chlorine bleach fastness. Existing chlorine-resistant color-fixing agent technologies, patents CN 106978741 A and CN 115627647 A, disclose color-fixing agents using hyperbranched polyethyleneimine as the main chlorine-resistant raw material. While these patents offer some chlorine resistance, their color-fixing effect is generally limited. For fabrics requiring high color fastness, an additional color-fixing treatment is necessary. Therefore, to conserve resources and improve production efficiency, there is an urgent need to develop a color-fixing agent that combines good chlorine fastness and color-fixing effect, in line with the trend of energy conservation and emission reduction. Summary of the Invention

[0005] To improve the color-fixing effect of chlorine-resistant color-fixing agents or enhance the chlorine resistance of conventional formaldehyde-free color-fixing agents, this invention presents a novel environmentally friendly chlorine-resistant color-fixing agent that combines color-fixing effect and chlorine bleach fastness. This method and its application involve introducing quaternary ammonium salt cationic groups and a polyurethane structure into a polyethyleneimine polymer backbone rich in amine groups, thus significantly improving color-fixing performance. The novel environmentally friendly chlorine-resistant color-fixing agent of this invention contains a large number of unsaturated amine groups, exhibiting good chlorine bleach fastness. Simultaneously, the introduction of quaternary ammonium salt cationic groups further increases cationicity, reacting with reactive dyes to form water-insoluble lakes. Furthermore, the introduction of a polyurethane structure, through the unsealing and release of -NCO groups, further forms strong chemical bonds with fibers or dyes. This structure can form a polymer film on the surface of cotton fibers, firmly encapsulating the dye, thus providing excellent color-fixing performance. Therefore, this novel environmentally friendly chlorine-resistant color-fixing agent combines excellent chlorine fastness, color-fixing effect, and hydrophilic properties. After color-fixing treatment, cotton fabrics can meet the color fastness requirements of printing and dyeing plants for fabrics leaving the factory, thus overcoming the shortcomings of existing technologies.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A method for preparing a novel environmentally friendly chlorine-resistant color-fixing agent includes: A) Preparation of intermediates: A certain amount of polyethylene glycol (PEG) was added to a reaction flask and dehydrated at 120 °C and -0.1 MPa (relative vacuum) for 1 h. The temperature was then lowered to below 60 °C, and TDI (a mixture of 80% toluene-2,4-diisocyanate and 20% toluene-2,6-diisocyanate) and a solvent (one of dipropylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, and ethylene glycol diacetate) were added. The reaction was maintained at 60-65 °C for 1 h, and the temperature was lowered to obtain a polyurethane prepolymer. ②The polyurethane prepolymer from step j is then slowly added dropwise to polyethyleneimine (linear or branched type, molecular weight 600-10000), with the temperature controlled below 40℃. Then, end-capping agents (sodium bisulfite, N-methylbenzylamine, 3,5-dimethylpyrazole) are added, and the reaction is maintained at this temperature for 1 hour. Water is then added to obtain an intermediate product for later use. Taking linear polyethyleneimine as an example, its reaction process and molecular structure are shown below:

[0007]

[0008] Where n is an integer from 2 to 50, and m is an integer from 10 to 250; B) Preparation of environmentally friendly chlorine-resistant color-fixing agents A certain amount of the intermediate product from step (a) was added to a reaction flask, stirred, and a cationic etherifying agent (2,3-epoxypropyltrimethylammonium chloride) was slowly added dropwise, with the temperature controlled at 20-40℃. After the addition was complete, the reaction was maintained at 60-80℃ for 3-5 hours. Finally, the pH was adjusted to 5-7 with glacial acetic acid, and the mixture was cooled to obtain an environmentally friendly chlorine-resistant color-fixing agent. The reaction process and molecular structure are shown below:

[0009] Where n is an integer from 2 to 50; m is an integer from 10 to 250; x, y, and z are integers from 0 to 250, and x + y + z = m.

[0010] Application of the above-mentioned novel environmentally friendly chlorine-resistant color-fixing agent: Prepare a 2.0-4.0% color-fixing agent working solution by mixing the novel environmentally friendly chlorine-resistant color-fixing agent with water; then immerse the cotton fabric to be treated in the color-fixing agent working solution at an immersion temperature of 40-50 ℃, an immersion bath ratio of 1:10, and an immersion time of 20-30 min; finally, wet-set the cotton fabric at 150 ℃ for 100 s.

[0011] The above technical solution offers the following advantages: The novel environmentally friendly chlorine-resistant color-fixing agent of this invention possesses numerous unsaturated amine and quaternary ammonium salt groups, as well as a polyurethane structure, exhibiting both excellent chlorine fastness and color-fixing effect. After color-fixing treatment, cotton fabrics achieve a wash fastness of 3-5 and a chlorine bleach fastness of 2-4, meeting the national standard of moisture absorption within 5 seconds. With just one color-fixing treatment, all color fastness properties meet factory requirements, thus saving resources and meeting the needs of dyeing and printing plants. Detailed Implementation

[0012] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Example

[0013] (1) Preparation of intermediate products: ① Add 35 parts of polyethylene glycol 400 (PEG400) to a reaction flask, dehydrate at 120 ℃ and -0.1 MP (relative vacuum) for 1 h, cool down to below 60 ℃, add 55 parts of TDI (a mixture of 80% toluene-2,4-diisocyanate and 20% toluene-2,6-diisocyanate) and 10 parts of dipropylene glycol dimethyl ether, keep the reaction at 60~70 ℃ for 1 h, cool down to obtain polyurethane prepolymer; ② Slowly add 17 parts of the polyurethane prepolymer from step ① to 21 parts of polyethyleneimine (linear type, molecular weight about 600), while controlling the temperature below 40°C. After the addition is complete, keep the reaction at the temperature for 0.5 hours. Then add 2 parts of the end-capping agent 3,5-dimethylpyrazole and continue to keep the reaction at the temperature for 1 hour. Add water to obtain an intermediate product with a solid content of about 40% for later use. (2) Preparation of environmentally friendly chlorine-resistant color-fixing agent: Add 82 parts of the intermediate product from step (1) and 14 parts of deionized water to the reaction flask, stir, and slowly add 4 parts of cationic etherifying agent (2,3-epoxypropyltrimethylammonium chloride) dropwise, with the temperature controlled at 20-40℃. After the addition is complete, keep the reaction at 60-80℃ for 3-5 hours. Finally, adjust the pH value to 5-7 with glacial acetic acid and cool down to obtain the environmentally friendly chlorine-resistant color-fixing agent. Example

[0014] (1) Preparation of intermediate products: Same as in Example 1; (2) Preparation of environmentally friendly chlorine-resistant color-fixing agent: Add 76 parts of the intermediate product from step (1) and 18 parts of deionized water to the reaction flask, stir, and slowly add 6 parts of cationic etherifying agent (2,3-epoxypropyltrimethylammonium chloride) dropwise, with the temperature controlled at 20-40℃. After the addition is complete, keep the reaction at 60-80℃ for 3-5 hours. Finally, adjust the pH value to 5-7 with glacial acetic acid and cool down to obtain the environmentally friendly chlorine-resistant color-fixing agent. Example

[0015] (1) Preparation of intermediate products: ① Add 35 parts of polyethylene glycol 400 (PEG400) to a reaction flask, dehydrate at 120 ℃ and -0.1 MP (relative vacuum) for 1 h, cool down to below 60 ℃, add 55 parts of TDI (a mixture of 80% toluene-2,4-diisocyanate and 20% toluene-2,6-diisocyanate) and 10 parts of dipropylene glycol dimethyl ether, keep the reaction at 60~70 ℃ for 1 h, cool down to obtain polyurethane prepolymer; ② Slowly add 15 parts of the polyurethane prepolymer from step ① to 23 parts of polyethyleneimine (linear type, molecular weight about 4000), while controlling the temperature below 40°C. After the addition is complete, keep the reaction at the temperature for 0.5 hours. Then add 2 parts of the end-capping agent 3,5-dimethylpyrazole and continue to keep the reaction at the temperature for 1 hour. Add water to obtain an intermediate product with a solid content of about 40% for later use. (2) Preparation of environmentally friendly chlorine-resistant color-fixing agent: Add 81 parts of the intermediate product from step (1) and 14 parts of deionized water to the reaction flask, stir, and slowly add 5 parts of cationic etherifying agent (2,3-epoxypropyltrimethylammonium chloride) dropwise, with the temperature controlled at 20-40℃. After the addition is complete, keep the reaction at 60-80℃ for 3-5 hours. Finally, adjust the pH value to 5-7 with glacial acetic acid and cool down to obtain the environmentally friendly chlorine-resistant color-fixing agent. Example

[0016] (1) Preparation of intermediate products: ① Add 48 parts of polyethylene glycol 2000 (PEG2000) to a reaction flask, dehydrate at 120 ℃ and -0.1 MP (relative vacuum) for 1 h, cool down to below 60 ℃, add 42 parts of TDI (a mixture of 80% toluene-2,4-diisocyanate and 20% toluene-2,6-diisocyanate) and 10 parts of propylene glycol monomethyl ether acetate, keep the reaction at 60~70 ℃ for 1 h, cool down to obtain polyurethane prepolymer; ② Slowly add 12 parts of the polyurethane prepolymer from step ① to 26 parts of polyethyleneimine (linear type, molecular weight about 4000), while controlling the temperature below 40°C. After the addition is complete, keep the reaction at the temperature for 0.5 hours. Then add 2 parts of the end-capping agent N-benzylmethylamine and continue to keep the reaction at the temperature for 1 hour. Add water to obtain an intermediate product with a solid content of about 40% for later use. (2) Preparation of environmentally friendly chlorine-resistant color fixing agent: Add 86 parts of the intermediate product from step (1) and 14 parts of deionized water to the reaction flask, stir, and slowly add 4 parts of cationic etherifying agent (2,3-epoxypropyltrimethylammonium chloride) dropwise, with the temperature controlled at 20-40℃. After the addition is complete, keep the reaction at 60-80℃ for 3-5 hours. Finally, adjust the pH value to 5-7 with glacial acetic acid and cool down to obtain the environmentally friendly chlorine-resistant color fixing agent. Example

[0017] (1) Preparation of intermediate products: ① Add 44 parts of polyethylene glycol 1000 (PEG1000) to a reaction flask, dehydrate at 120 ℃ and -0.1 MP (relative vacuum) for 1 h, cool down to below 60 ℃, add 46 parts of TDI (a mixture of 80% toluene-2,4-diisocyanate and 20% toluene-2,6-diisocyanate) and 10 parts of propylene glycol monomethyl ether acetate, keep the reaction at 60~70 ℃ for 1 h, cool down to obtain polyurethane prepolymer; ②Then slowly add 11 parts of the polyurethane prepolymer from step ① to 27 parts of polyethyleneimine (linear type, molecular weight about 4000), and control the temperature below 40°C during the process. After the addition is complete, keep the reaction at the temperature for 0.5 hours. Then add 2 parts of the end-capping agent N-benzylmethylamine and continue to keep the reaction at the temperature for 1 hour. Add water to obtain an intermediate product with a solid content of about 40% for later use. Preparation of environmentally friendly chlorine-resistant color-fixing agent: Add 80 parts of the intermediate product from step (1) and 15 parts of deionized water to a reaction flask, stir, and slowly add 5 parts of cationic etherifying agent (2,3-epoxypropyltrimethylammonium chloride) dropwise, controlling the temperature at 20-40℃. After the addition is complete, keep the reaction at 60-80℃ for 3-5 hours. Finally, adjust the pH value to 5-7 with glacial acetic acid and cool down to obtain the environmentally friendly chlorine-resistant color-fixing agent.

[0018] The usage method and application performance test of the newly obtained environmentally friendly chlorine-resistant fixing agent include the following steps: (1) Method of use: Prepare a 2.0-4.0% (ow f) fixing agent working solution by mixing the chlorine-resistant fixing agent involved in this invention with water; then immerse the cotton fabric to be treated in the fixing agent working solution, wherein the immersion temperature is 40~50 ℃, the immersion bath ratio is 1:10, and the immersion time is 20~30 min; finally, wet set the cotton fabric at 150 ℃ for 100 s.

[0019] (2) Application performance test methods: (a) Hydrophilicity is determined by the water drop method; (b) Wash fastness is determined according to GB / T3921C-2008 "Textiles - Tests for color fastness: Wash fastness"; (c) Chlorine fastness and active chlorine solution are determined and prepared according to GB / T 8433-2013 "Textiles - Tests for color fastness: Chlorine fastness"; (d) The rating of wash fastness and chlorine fastness is based on GB / T250-280 gray scale.

[0020] The application performance of Examples 1-5 above was tested, and the results are shown in Tables 1, 2, and 3: Table 1. Results of hydrophilicity test

[0021] Table 2 Results of color fastness test for washing

[0022] Table 3. Results of Chlorine Fastness Test

Claims

1. A method for preparing a novel environmentally friendly chlorine-resistant color-fixing agent, characterized in that... Includes the following steps: 1) Preparation of intermediates: ① Polyethylene glycol was added to a reaction flask and dehydrated at 120℃ and -0.1MP relative vacuum for 1 hour. The temperature was then lowered to below 60℃, and TDI and solvent were added. The reaction was carried out at 60-65℃ for 1 hour, and the temperature was lowered to obtain polyurethane prepolymer. Among them, TDI is a mixture of 80% toluene-2,4-diisocyanate and 20% toluene-2,6-diisocyanate. ② The polyurethane prepolymer from step ① is slowly added dropwise to polyethyleneimine, while the temperature is controlled below 40°C. Then, a capping agent is added and the reaction is kept at a constant temperature for 1 hour. Water is then added to obtain the intermediate product. 2) Preparation of environmentally friendly chlorine-resistant color fixing agent: Add the intermediate from step 1) to the reaction flask, stir, slowly add the cationic etherifying agent, and control the temperature at 20-40℃; after the addition is complete, keep the reaction at 60-80℃ for 3-5 hours, and finally adjust the pH value to 5-7 with glacial acetic acid, and cool down to obtain the environmentally friendly chlorine-resistant color fixing agent.

2. The preparation method of a novel environmentally friendly chlorine-resistant fixing agent according to claim 1, characterized in that: The solvent is one of dipropylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, and ethylene glycol diacetate; the polyethyleneimine is linear or branched, with a molecular weight of 600-10000; the end-capping agent contains sodium bisulfite, or N-methylbenzylamine, or 3,5-dimethylpyrazole, and the cationic etherifying agent is 2,3-epoxypropyltrimethylammonium chloride.

3. The preparation method of a novel environmentally friendly chlorine-resistant color-fixing agent according to claim 1 or 2, characterized in that: Taking linear polyethyleneimine as an example, the reaction process and molecular structure are as follows: Where n is an integer from 2 to 50, and m is an integer from 10 to 250; Where n is an integer from 2 to 50; m is an integer from 10 to 250; x, y, and z are integers from 0 to 250, and x + y + z = m.

4. The application of a novel environmentally friendly chlorine-resistant color-fixing agent, characterized in that: The novel environmentally friendly chlorine-resistant color-fixing agent is prepared by any one of the preparation methods described in claims 1 to 3. The novel environmentally friendly chlorine-resistant color-fixing agent is mixed with water to prepare a color-fixing agent working solution of 2.0-4.0%; then the cotton fabric to be treated is immersed in the color-fixing agent working solution at an immersion temperature of 40-50°C, an immersion bath ratio of 1:10, and an immersion time of 20-30 min; finally, the cotton fabric is wet-set at 150°C for 100 s.

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