阅读说明：本技术 一种环境友好的棉织物用活性染料低温无盐染色方法 (Low-temperature salt-free dyeing method of environment-friendly reactive dye for cotton fabric ) 是由 方龙 牛天杰 张晓东 王雪梅 孙德帅 杜辉 于 2019-12-12 设计创作，主要内容包括：本发明涉及了一种环境友好的棉织物用活性染料低温无盐染色方法,包括阳离子聚合物的合成,棉织物的改性处理、染色以及染料废水的絮凝等步骤。用二甲基二烯丙基氯化铵和烯丙基缩水甘油醚在过硫酸钾做引发剂的条件下合成阳离子聚合物,将棉织物浸入一定浓度的阳离子聚合物水溶液中改性处理。经改性后的棉织物可用活性染料在低温、无盐的条件下染色,提高了染料的上染率和固色率,且匀染性良好。改性棉织物的水洗液与染色残液和皂洗液混合,利用溶液里的少量阳离子聚合物将染色废水中的残余染料絮凝下来,大大减少了印染废水的排放,有利于实际生产和环境保护。(The invention relates to an environment-friendly low-temperature salt-free dyeing method of a reactive dye for cotton fabrics, which comprises the steps of synthesis of a cationic polymer, modification treatment of the cotton fabrics, dyeing, flocculation of dye wastewater and the like. Dimethyl diallyl ammonium chloride and allyl glycidyl ether are used for synthesizing a cationic polymer under the condition that potassium persulfate is used as an initiator, and the cotton fabric is immersed into a cationic polymer aqueous solution with a certain concentration for modification treatment. The modified cotton fabric can be dyed by reactive dyes under the conditions of low temperature and no salt, the dye uptake and the fixation rate of the dyes are improved, and the level dyeing property is good. The washing liquid of the modified cotton fabric is mixed with the dyeing residual liquid and the soaping liquid, and a small amount of cationic polymer in the solution is utilized to flocculate residual dye in the dyeing wastewater, so that the discharge of the printing and dyeing wastewater is greatly reduced, and the practical production and the environmental protection are facilitated.)

1. An environment-friendly low-temperature salt-free dyeing method of a reactive dye for cotton fabrics comprises the working procedures of cationic polymer synthesis, cotton fabric modification treatment, dyeing, dye wastewater post-treatment and the like, and comprises the following steps:

(1) adding dimethyl diallyl ammonium chloride and allyl glycidyl ether into a three-neck flask according to the mass ratio of 7.5:1, adding potassium persulfate accounting for 1% of the total mass of the monomers as an initiator at one time, stirring and reacting for 4 hours at 70-90 ℃, taking out, naturally cooling to room temperature, adding acetone to separate out a product, and performing vacuum drying at 50 ℃;

(2) preparing the synthesized cationic polymer into a cationic polymer aqueous solution with the concentration of 0.7g/L by using deionized water, adding sodium hydroxide to adjust the pH value of the aqueous solution to be 13, immersing the cotton fabric into the solution at the bath ratio of 1:100, keeping the temperature of 25 ℃, slowly stirring for 6 hours, taking out and washing to be neutral;

(3) the modified cotton fabric is subjected to low-temperature salt-free dyeing by using a reactive dye, and is characterized in that the salt-free dyeing method comprises the steps of dip dyeing for 0.5h at 25 ℃, slowly heating to 35 ℃, adding 15g/L of sodium carbonate, fixing color for 4h, washing with water, soaping for 10min at 95 ℃ by using 1g/L of soap chip water solution, washing with water, and drying in the air; the reactive dyes are reactive black KN-B, reactive brilliant blue KN-R, reactive turquoise blue KN-G, reactive yellow 3RS and reactive red 3 BSN.

2. The method for low-temperature salt-free dyeing of cotton fabrics with reactive dyes according to claim 1, characterized in that the cationic polymer has a cationicity of 3.034mmol/g and a weight average molecular weight of 2315 g/mol.

3. The method for low-temperature salt-free dyeing of cotton fabrics by using the reactive dye as claimed in claim 1, is characterized in that the dye wastewater and soap washing liquor can be flocculated by using the water washing liquor of the modified cotton fabrics containing the cationic polymer, so that the dyeing residual liquor can be further purified, and the modification process can be greened: the cotton fabric is modified by the synthesized cationic polymer, then is fully washed by water, the washing liquid is mixed with the dyeing residual liquid and the soaping wastewater, the concentration of the cationic polymer in the mixed liquid is 50-100 mmg/L, and the mixture is stirred and kept stand.

Technical Field

The invention belongs to the field of salt-free dyeing of cotton fabrics by using reactive dyes.

Background

The reactive dye can form a covalent bond with cotton fibers in the dyeing process, has excellent dyeing fastness, bright color, complete color spectrum, low cost and very wide application, and becomes the most important dye for dyeing cotton fiber textiles. The reactive dye comprises three parts of a reactive group, a hydrophilic group and a dye parent, wherein the hydrophilic group generally consists of a sodium sulfonate salt, a hydroxyl group, an amino group and the like, and the sulfonate group has a great contribution to the hydrophilicity of the dye. The presence of sulfonic acid groups helps the reactive dye to dissolve in water, so that the dyeing process can be carried out in an aqueous solution; however, the dye matrix is negatively charged due to the dissociation of the sodium sulfonate, so that the binding capacity to fiber negative ions is reduced, the dye matrix is easily hydrated to form a hydrate and is aggregated into a micelle structure, the effective concentration of the dye negative ions is reduced, and the dye uptake and the fixation rate of the reactive dye dyed cotton fiber are low. In order to solve the problem, a large amount of inorganic salt is usually added in the dyeing process to promote dyeing, but the waste water with high salt content generated in the dyeing process is difficult to treat and has great harm to the environment, and how to realize low-salt even salt-free dyeing of reactive dyes is a problem to be solved urgently.

At present, the approaches for improving the utilization rate of reactive dyes and reducing the use of inorganic salts in the dyeing process mainly comprise:

(1) development of novel reactive dyes: the double-active-group reactive dye and the multifunctional reactive dye have two or even a plurality of active groups in the molecule, and can effectively improve the utilization rate of the reactive dye from 50-60 percent to 70-80 percent; the cationic reactive dye can eliminate the requirement on electrolyte in the dyeing process, improve the affinity of the dye to fibers and realize salt-free dyeing.

(2) Optimizing the dyeing process: reducing the volume of the dye liquor can increase the concentration of the dye and inorganic salt in the dye liquor, so reducing the bath ratio is a feasible method for improving the utilization rate of the dye and reducing the use of the inorganic salt; the pad dyeing technology, especially the cold-pad-pile dyeing technology, not only reduces the use of dye and inorganic salt, but also reduces the energy consumption, and has high economical efficiency. In addition, the fixation polymerization technology, micelle dyeing technology and other novel dyeing processes have also been reported.

(3) Biodegradable organic compounds were used instead of inorganic salts: the mixed system of magnesium-based organic compounds is used for replacing inorganic salt in the dyeing process of the reactive dye cotton fabric, so that the discharge of salt-containing dye wastewater can be effectively prevented; the organic cationic surfactant and the sodium salt of the organic acid can also be used as substitutes of sodium chloride and sodium sulfate, so that the use of inorganic salt is avoided, and the utilization rate of the reactive dye is improved.

(4) Carrying out chemical modification on cotton fibers: the cotton fiber is pretreated by the group containing the cation before dyeing, so that positive charge can be introduced to the surface of the fiber, and the affinity of the fiber to the reactive dye is enhanced. The method can avoid the use of inorganic salt, and greatly improve the dyeing efficiency and the utilization rate of the reactive dye. Cationic agents for cotton fiber modification can generally be divided into two categories: the first type is a micromolecular cationic reagent, such as 3-chloro-2-hydroxypropyl trimethyl ammonium chloride and the like, and the cationic reagent can well enter the interior of the fiber due to small molecular weight, is relatively uniform in modification, but has a large using amount and a certain problem of environmental pollution; the other is a high molecular cationic polymer, which has a small amount of use because of its large molecular weight and high cationic degree, but the modification is often limited to the fiber surface, which easily causes non-uniform modification, thereby affecting dyeing effect.

Disclosure of Invention

The invention synthesizes a bifunctional cationic polymer: the copolymer of dimethyl diallyl ammonium chloride and allyl glycidyl ether can be used for chemically modifying cotton fibers and post-treating dyeing wastewater. Cationic polymers with moderate cationic degree and small molecular weight are prepared by controlling synthesis conditions, cotton fabrics can be uniformly modified under mild conditions, and the modified cotton fabrics can be dyed by reactive dyes under low-temperature and salt-free conditions, so that the total utilization rate of the dyes is greatly improved, and a good level dyeing effect can be obtained; in addition, a small amount of cationic polymer in the modified cotton cloth washing liquid can also carry out post-treatment on dyeing wastewater and soaping wastewater, so that secondary pollution is avoided, and green production is realized.

The technical scheme for implementing the invention comprises three parts,

the first part is the synthesis of cationic polymer, and the reaction principle is shown in the attached figure 1: weighing dimethyl diallyl ammonium chloride and allyl glycidyl ether according to the mass ratio of 7.5:1, adding the dimethyl diallyl ammonium chloride and the allyl glycidyl ether into a three-neck flask, adding potassium persulfate accounting for 1% of the total amount of monomers as an initiator, stirring at the constant temperature of 70-90 ℃ for reaction for 4 hours, naturally cooling to room temperature, adding acetone to separate out a product, and performing vacuum drying at the temperature of 50 ℃.

The second part is cotton fiber modification treatment: preparing the synthesized cationic polymer into aqueous solution with a certain concentration, adjusting the pH value of the aqueous solution by using sodium hydroxide solution, immersing the cotton fabric into the aqueous solution, keeping the temperature at 25 ℃, slowly stirring for reaction for 6 hours, washing the solution to be neutral, and airing the solution.

The third part is dyeing: reactive dye is adopted for dip dyeing at 25 ℃ under the salt-free condition, and sodium carbonate is added at 35 ℃ for fixation.

The modified cotton fabric has strong reactivity with the reactive dye, and the total utilization rate of the dye can be greatly improved under the salt-free condition. By controlling the synthesis conditions of the cationic polymer, the cationic polymer with moderate cationic degree and small molecular weight is obtained, and the cotton fabric is modified and dyed under the low-temperature condition, so that a good level dyeing effect can be obtained.

The synthesis and modification processes related by the invention can be well adapted to the existing equipment of a printing and dyeing mill, the operation is simple, and the existing printing and dyeing processes are not increased basically; the synthesized cationic polymer is used for modifying cotton fabrics, and greatly improves the utilization rate of the dye on the premise of ensuring level-dyeing property; a small amount of cations in the washing liquid of the modified cotton fabric can also flocculate residual dyes in dye wastewater, and the modified cotton fabric is economical, environment-friendly and high in practicability.

Drawings

FIG. 1 is a schematic diagram of the synthesis principle of a copolymer of cationic polymer-dimethyldiallylammonium chloride and allyl glycidyl ether in accordance with the embodiment of the present invention.

Detailed Description