TWI909942B - Dyeing auxiliaries, their manufacturing methods, and their applications in dyeing processes. - Google Patents

Abstract

This invention provides a dyeing auxiliary agent, its manufacturing method, and the dyeing process it applies to. Using gelatin, citric acid, epichlorohydrin, and sodium bisulfite as raw materials, a hydrolyzed gelatin derivative surfactant is synthesized through a reaction. The surfactant utilizes its agglomeration properties to capture and carry dye from dyeing and finishing wastewater into cellulose fabrics, aiming to increase the dyeing rate of the fabric during the dyeing process and reduce the dye residue rate in the subsequent wastewater.

Description

Dyeing auxiliaries, their manufacturing methods, and their applications in dyeing processes.

This invention belongs to the field of dyeing auxiliaries, and in particular to a dyeing auxiliary that can improve the color uptake rate during dyeing and reduce the dye residue rate in the wastewater generated subsequently, as well as its manufacturing method and the dyeing process in which it is applied.

Note: In the textile industry, the dyeing and finishing process is a crucial step, determining the quality of the finished product. While treatment technologies and methods have advanced significantly, the treatment of high-color wastewater from dyeing and finishing remains one of the most challenging issues in today's environmentally conscious world. The main pollutants in this wastewater are organic compounds from dyes. Discharging these substances into rivers can cause significant ecological impact. To ensure economic efficiency, the dyeing and finishing industry primarily employs biological treatment and chemical coagulation processes for wastewater treatment. Currently, approximately 10,000 different dyes are used in industrial production, along with 7 x ^10⁵ auxiliaries produced worldwide. However, even with the use of existing auxiliaries on the market to assist in the dyeing and finishing process, about 20 to 25% of the dye compounds still cannot adhere to the fabric during the dyeing and finishing process and are discharged with the wastewater. Therefore, more effective auxiliaries are needed in the manufacturing process to reduce the damage of dyeing and finishing wastewater to the environment.

In view of this, the inventor, feeling that the technology was not perfect, devoted himself to research and, based on his years of experience in the industry, has provided a dyeing auxiliary agent, its manufacturing method, and the dyeing process in which it is applied, in order to improve the deficiencies of the aforementioned conventional technology.

Therefore, one objective of this invention is to provide a dyeing auxiliary agent, its manufacturing method, and the dyeing process in which it is applied, so as to increase the dyeing rate of fabric and reduce the dye residue rate in the wastewater generated subsequently.

To achieve the above objectives, the dyeing auxiliary of this invention is designed to improve the dyeing rate during dyeing and reduce the dye residue rate in the wastewater generated subsequently. The characteristic feature is that the general formula of the dyeing auxiliary is: And n is 10~100, while _R1 , _{R2 , and R3} are alkyl groups.

Furthermore, this invention also provides a method for preparing a dyeing auxiliary agent, comprising the following steps: (A) Dissolving 0.1 mol of citric acid in water, then adding alcohol and placing it in a four-hole reaction vessel and stirring for 30 minutes, while heating to 80°C during stirring, to generate a first excess product and water; (B) Adding 50 ml of 20% gelatin to the first excess product and heating to 80°C, reacting for 1-2 hours to generate a second excess product; (C) Cooling the second excess product to room temperature, then adding 50 ml of a mixed solution of epichlorohydrin and sodium bisulfite, and stirring at a constant temperature of 60°C for 1-2 hours to generate the dyeing auxiliary agent, wherein the molar ratio of epichlorohydrin and sodium bisulfite is 1:1. The general formula for the staining auxiliary agent is: And n is 10~100, while _R1 , _{R2 , and R3} are alkyl groups.

Preferably, the present invention further includes the following steps: (D) dissolving the dyeing auxiliary in ethanol, filtering it, and then removing the solvent by depressurized distillation to obtain the dyeing auxiliary with high purity.

Furthermore, this invention provides a dyeing process that utilizes a dyeing auxiliary to improve the color uptake rate, comprising the following steps: (1) adding dye and a dyeing auxiliary to a steel cylinder; (2) placing a fibrous fabric into the steel cylinder and sealing it for dyeing; and (3) removing the fibrous fabric and subjecting it to water washing and soap washing, followed by natural drying. The general formula of the dyeing auxiliary is: And n is 10~100, while _R1 , _{R2 , and R3} are alkyl groups.

Ideally, the fiber fabric is placed in a sealed steel cylinder and then heated for dyeing, starting at 30°C and increasing at a rate of 2°C per minute.

Ideally, the fabric should be made of cotton fibers.

In this way, the dyeing auxiliary provided by the present invention can significantly reduce the content of dye compounds in wastewater after dyeing, thereby reducing pollution after wastewater discharge. The dyeing process described above can also improve the dyeing rate of the fabric while reducing the proportion of dye compounds in the wastewater generated after the process due to the addition of the dyeing auxiliary.

To ensure that your review committee can clearly understand the contents of this invention, please refer to the following explanations and illustrations.

In this embodiment, the dyeing auxiliary provided by the present invention is prepared by the following method: First, 0.1 mol of citric acid is dissolved in water, then alcohol is added and the mixture is placed in a four-hole reaction vessel and stirred for 30 minutes. During stirring, the mixture is heated to 80°C to generate a first excess product and water. Next, 50 ml of 20% gelatin is added to the first excess product and heated to 80°C. The mixture is reacted for 1-2 hours to generate a second excess product. Finally, the second excess product is cooled to room temperature, and then 50 ml of a mixed solution of epichlorohydrin and sodium bisulfite is added. The mixture is stirred at a constant temperature of 60°C for 1-2 hours to generate the dyeing auxiliary, wherein the molar ratio of epichlorohydrin to sodium bisulfite is 1:1. At this point, the chemical structure of the dyeing auxiliary is as follows: Furthermore, n is 10~100, and _R1 , _{R2 , and R3} are alkyl groups. After the process is completed, further processing can be carried out to purify the compound. The raw materials of the incomplete reaction are dissolved in ethanol and then filtered. The solvent and excess water are then removed by depressurized distillation to obtain a compound with higher purity. Different concentrations can be adjusted according to different dyeing conditions.

Figure 1 is a data analysis of the dyeing auxiliary to confirm whether it possesses the characteristics of an auxiliary. The X-axis represents the auxiliary concentration, the Y-axis represents surface tension, and gelatin is hydrolyzed gelatin. Gelatin-CA is the dyeing auxiliary of this invention. At 25°C, the surface tension of pure water is approximately 72.4 dyne/cm. When an auxiliary agent is added, the surface tension decreases as the concentration increases. As shown in Figure 1, the surface tension decreases significantly after the addition of the dyeing auxiliary agent. Furthermore, as the concentration of the added auxiliary agent increases to a certain level, the surface tension also decreases slightly. This indicates that the dyeing auxiliary agent possesses auxiliary properties. This is because the addition of the surfactant to the aqueous solution reduces the surface tension. This is due to the arrangement of the hydrophilic group of the surfactant remaining in the liquid while the hydrophobic group protrudes above the water surface. Furthermore, as shown in Figure 1, the surface tension of the hydrolyzed gelatin derivative Gelatin-CA is lower than that of hydrolyzed gelatin. This facilitates dye penetration into the fiber. This is because the dyeing auxiliary has multiple hydrophilic groups, while the hydrophobic groups of the surfactant are less likely to form a tight, regular adsorption arrangement on the water surface, thus reducing the surface tension less significantly.

Figure 2 is a schematic diagram showing the results of an experiment conducted to determine whether adding the dyeing auxiliary would produce excessive foam. Gelatin is hydrolyzed gelatin, and Gelatin-CA is the dyeing auxiliary of this invention. Pure water does not foam, but when the solution contains a surfactant, the solution is stirred, and air enters the solution, forming bubbles. At this time, the auxiliary is adsorbed at the liquid-gas phase interface, forming an elastic film. Therefore, if gas is present in the liquid, foam will be generated. Figure 2 shows that the foam height of the derivative Gelatin-CA is lower than that of gelatin, and the foam stability is also lower. Experiments show that the foam from the derivative Gelatin-CA almost disappeared within five minutes of the instrument stopping, while the gelatin still retained 0.1 cm of foam. This is beneficial for environmental protection and reducing the discharge of polluting wastewater. If the foam does not dissipate, it will cause anoxidation in rivers, increasing the environmental burden.

In the dyeing process, the ideal situation is for the dyed fabric to completely absorb the dye, which not only makes the finished product close to the original color of the dye, but also solves the problem of excessive color in the wastewater discharge. However, this is often difficult to achieve in actual on-site operation. Therefore, this invention provides a dyeing process in this embodiment that uses the above-mentioned dyeing auxiliary to improve the coloring rate and reduce the dye residue rate in the wastewater, including the following steps: (1) adding dye and a dyeing auxiliary to a steel cylinder; (2) placing a fiber fabric into the steel cylinder and sealing it for dyeing; and (3) taking out the fiber fabric and washing it with water and soap, and then allowing it to dry naturally. In this embodiment, the fiber fabric being dyed is made of cotton fiber. The process involves placing the fiber fabric into a sealed steel cylinder and then heating it at a rate of 2°C per minute, starting from 30°C. This heating rate ensures a more stable dyeing process and improves the color uptake rate.

Figures 3 to 6 are schematic diagrams showing the results of detecting the color uptake rate of cotton fabrics after the dyeing process is completed, for different concentrations of auxiliary agents, holding times, dye concentrations, and dye types. Gelatin is hydrolyzed gelatin, Gelatin-CA is the dyeing auxiliary agent of this invention, and Blank represents the control group without the addition of auxiliary agents.

As can be observed from Figure 3, the coloring rate increases with the increase of the additive concentration. A higher coloring rate can be obtained when the concentration of its derivative Gelatin-CA reaches 10 g/L. When the concentration is further increased, the coloring rate does not increase significantly. Therefore, the concentration of its derivative Gelatin-CA should be 10 g/L to obtain a high coloring rate.

The dyeing process generally includes three stages: adsorption, diffusion, and fixation. Each stage requires a certain amount of time to complete the dyeing process. As shown in Figure 4, the dyeing rate of hydrolyzed gelatin and its derivative Gelatin-CA increases with increasing holding time. Compared to samples without additives and those with added hydrolyzed gelatin, the addition of Gelatin-CA significantly improves the dyeing rate of cotton fabrics. Gelatin-CA exhibits the highest dyeing rate at 60 minutes; further increases in holding time slightly decrease the dyeing rate. Therefore, a holding time of 60 minutes is optimal; excessive holding time only increases dyeing costs and wastes electricity.

To achieve a darker color in fabric, the dye concentration must be increased. Therefore, knowing the fabric's maximum dye absorption value is crucial. As shown in Figure 5, the dye uptake rate of cotton fabric increases with increasing dye concentration. However, when the dye concentration reaches 1%, the uptake rate only increases slightly. Therefore, the optimal dye concentration for cotton fabric is 1%. Furthermore, using the derivative Gelatin-CA as a dyeing auxiliary agent results in a higher uptake rate for cotton fabrics compared to those using hydrolyzed gelatin or without any additives.

Figure 6 compares the dye uptake rates of cotton fabrics with different dyes when gelatin and its derivative Gelatin-CA are added to the dye bath. Figure 6 shows that Gelatin-CA exhibits high dye uptake rates on cotton fabrics with all direct dyes, showing a significant difference compared to the group treated with gelatin and the group without added auxiliaries. This demonstrates that Gelatin-CA effectively improves the dye uptake rate of cotton fabrics regardless of the color.

In summary, the experimental data above show that adding the dyeing auxiliary agent provided by this invention during dyeing increases the dye uptake rate of cotton fabrics to direct dyes. It also has the following advantages or effects: 1. To achieve a high dye uptake rate when using the hydrolyzed gelatin derivative Gelatin-CA as an auxiliary agent for dyeing cotton fabrics, the optimal conditions are an auxiliary agent concentration of 10 g/L and a dyeing holding time of 60 minutes; and it has a dyeing aid effect on various direct dye colors. 2. Using the hydrolyzed gelatin derivative Gelatin-CA as a dyeing and finishing auxiliary agent can reduce the difficulty of treating wastewater after dyeing, and this auxiliary agent is biodegradable and environmentally friendly. Therefore, this dyeing auxiliary agent can indeed improve the dye uptake rate of fabrics, while also reducing the residual dye content in the wastewater generated later, thus avoiding further environmental pollution.

However, the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Therefore, any equivalent changes and modifications made without departing from the spirit and scope of the present invention shall be covered within the patent scope of the present invention.

Figure 1 shows experimental data on whether dyeing auxiliaries possess the characteristics of auxiliaries. Figure 2 shows experimental data on whether dyeing auxiliaries produce excessive foam. Figure 3 shows experimental data on the color uptake rate of cotton fabrics with different concentrations of dyeing auxiliaries. Figure 4 shows experimental data on the color uptake rate of cotton fabrics with different heat treatment times with dyeing auxiliaries. Figure 5 shows experimental data on the color uptake rate of cotton fabrics with different dye concentrations with dyeing auxiliaries. Figure 6 shows experimental data on the color uptake rate of cotton fabrics with different dyes with dyeing auxiliaries.

Claims (6)

A dyeing auxiliary agent, designed to improve the dyeing rate and reduce the dye residue in subsequent wastewater, is characterized in that: the general formula of the dyeing auxiliary agent is: And n is 10~100, while _R1 , _{R2 , and R3} are alkyl groups. A method for preparing a dyeing auxiliary includes the following steps: (A) Dissolving 0.1 mol of citric acid in water, then adding alcohol and placing it in a four-hole reaction vessel, stirring for 30 minutes, and heating to 80°C during stirring to generate a first excess product and water; (B) Adding 50 ml of 20% gelatin to the first excess product and heating to 80°C, reacting for 1-2 hours to generate a second excess product; (C) Cooling the second excess product to room temperature, then adding 50 ml of a mixed solution of epichlorohydrin and sodium bisulfite, and stirring at a constant temperature of 60°C for 1-2 hours to generate the dyeing auxiliary, wherein the molar ratio of epichlorohydrin and sodium bisulfite is 1:1, and the general formula of the dyeing auxiliary is: And n is 10~100, while _R1 , _R2 , and _R3 are alkyl groups. The method described in claim 2 further includes the following steps: (D) dissolving the dyeing auxiliary in ethanol, filtering it, and then removing the solvent by depressurized distillation to obtain the dyeing auxiliary with high purity. A dyeing process for improving color uptake using a dyeing auxiliary includes the following steps: (1) adding dye and a dyeing auxiliary to a steel cylinder; (2) placing a fibrous fabric into the steel cylinder, sealing it, and then dyeing it; and (3) removing the fibrous fabric, washing it with water and soap, and then allowing it to air dry; wherein the general formula of the dyeing auxiliary is: And n is 10~100, while _R1 , _{R2 , and R3} are alkyl groups. The dyeing process described in claim 4 involves placing the fibrous fabric into a sealed steel cylinder and then heating and dyeing it starting at 30°C at a rate of 2°C per minute. The dyeing process described in claim 5, wherein the material of the fibrous fabric is cotton fiber.