JP2001089979A - Method for dyeing of cloth containing cellulosic fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for dyeing a cellulosic cloth by using a vat dye and not giving an excess tension to the cloth, capable of exhibiting a uni form color and a high color reproducibility, giving a dyed material without a wrinkle and also improving its abrasion resistance. SOLUTION: This method for dyeing the cloth containing the cellulosic fiber is provided by fixing the cloth to be dyed in a dyeing machine so as not to touch the material to be dyed with the wall, etc., of the casing of the dyeing machine, eliminating oxygen in the dyeing machine, performing a reduction treatment, and then performing an oxidation treatment by putting an oxidizing agent while maintaining the oxygen-less state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for uniformly dyeing a fabric containing cellulose fibers. The fabric containing the cellulose-based fibers referred to in the present invention refers to a cellulose-based fiber such as cotton, hemp, and regenerated cellulose fibers, and the above-mentioned cellulose-based fibers, and a blended or mixed fiber of a synthetic fiber or a semi-synthetic fiber such as polyester, nylon, or acetate. It refers to fabrics such as fine, cross-knitted, woven or knitted fabrics.

[0002]

2. Description of the Related Art Outdoor sports clothing has recently been mainly composed of a cellulosic fiber or a fabric composed of a blend of these fibers and a synthetic fiber, a mixture of fibers, and a mixture of knitted fabrics. In addition, dyeings having excellent fastnesses are required. At present, these products are dyed mainly using reactive dyes by using direct dyes or the like, but have problems in light fastness, chlorine water fastness and the like.

As a method for solving these problems, a dyeing method using a vat dye excellent in various fastnesses has been studied. However, in the immersion dyeing method, the initial striping property peculiar to the vat dye is fast. The spots, reduction spots, oxidation spots, and the like are scarcely put to practical use due to disaster. A method of dyeing cotton products by substituting air in the gas phase with an inert gas using a partial jet dyeing machine has been disclosed (Japanese Patent Publication No. 6-94632). Also, a method of dyeing after removing a large amount of oxygen by adding a large amount of a reducing agent to the gas phase has been attempted (BASF technical data).

[0004]

In the above prior art,
In the continuous dyeing method applied to woven fabrics, tension is applied in the vertical direction to prevent wrinkles from occurring, so that the texture tends to be flat. Further, in the knitted fabric, the tension is applied in the vertical direction, so that the texture becomes rough and hard, and the washing shrinkage in the vertical direction becomes large, so that it is not practically usable. Therefore, it is used only in the class of knitted fabrics of thick fabric.

[0005] In order to prevent staining spots, a method of removing oxygen in the dyeing machine by adding a large amount of a reducing agent (technical data of BASF) has been tried. Has the drawbacks that the color reproducibility is poor due to the effect of dissolved oxygen, and oxidation spots are formed during the oxidation treatment.

A method has been proposed in which the inside of the dyeing machine is replaced with an inert gas using a liquid jet dyeing machine to perform dyeing. However, wrinkles are easily formed and the dissolved oxygen in the dyeing solution is sufficiently exchanged with the inert gas for gas-liquid exchange. Therefore, there are problems such as occurrence of staining spots due to partial oxidation spots and poor color reproducibility.

[0007] The dyeing method according to the present invention provides a dyeing method that uses a vat dye and does not impart unnecessary tension to a fabric, and that is uniform and has high color reproducibility, and also improves friction fastness. It is the purpose.

[0008]

The dyeing method according to the present invention is a method for dyeing a fabric containing cellulose fibers with a vat dye using a dyeing machine that fixes an object to be dyed and circulates only a dyeing solution. The object to be dyed is always immersed in the dyeing solution and the object to be dyed is not brought into contact with the gas phase of the dyeing machine, and furthermore, an inert gas or a reactive gas is introduced into the gas phase to replace the air, Simultaneously, the dissolved oxygen contained in the staining solution is transferred to the gas phase to create an oxygen-free staining solution, the dyeing object is fixed in the staining solution, and only the staining solution is circulated for staining. And a reduction treatment, and then an oxidizing agent is added while maintaining the oxygen-free state to continue the oxidation treatment. Hereinafter, the present invention will be described in detail.

In the present invention, the term "cloth containing cellulosic fibers" refers to cotton, hemp, regenerated cellulosic fibers, blended fibers, synthetic fibers such as polyester, nylon and acetate fibers, semi-synthetic fibers, blended fibers, mixed fibers, and mixed fibers. Knitting, woven and knitted fabrics are included. Vat dyes are indigo-based and anthraquinone-based compounds that are insoluble in water and have little affinity for cellulose fibers. A series of dyes that form sodium leuco compounds with strong affinity.

In the dyeing process of a vat-containing fabric containing cellulose fibers with a vat dye, the water-insoluble vat dye in the dyeing bath is converted into a water-soluble leuco salt by an alkali agent and a reducing agent to give a cellulose fiber. It is achieved by returning to a dye structure which is adsorbed and then oxidized by the oxidizing agent and is insoluble in water. As described above, vat dyes have disadvantages that the dyeing process is complicated, so that uniform dyeing is difficult to obtain and color reproducibility is poor. This is because the presence of air in the gas phase in the dyeing machine makes the reduction treatment and the oxidation treatment non-uniform.

The most important feature of the present invention is that, when a fabric containing cellulose fibers is dyed with a vat dye, a dyeing machine that fixes an object to be dyed and circulates only a dyeing solution is used.
The material to be dyed is constantly immersed in the dyeing solution so as not to come into contact with the gas phase, and the air in the gas phase in the dyeing machine is replaced by introducing another gas. In this state, the staining solution is circulated, and the dissolved oxygen in the staining solution is transferred to the gaseous phase portion, thereby creating an oxygen-free staining solution. The dyeing solution is fixed in the dyeing solution so that the material to be dyed does not come into contact with the wall surface of the can of the dyeing machine, and the dyeing solution is circulated to carry out the dyeing and reduction treatment. The oxidizing treatment is continuously performed by introducing an oxidizing agent therein.

By performing the dyeing / reducing treatment and the oxidizing treatment continuously in the oxygen-free dyeing solution, reduction spots and oxidation spots caused by oxygen in the air can be prevented, and uniform In addition, dyeing with high color reproducibility becomes possible.
In addition, since partial oxidation does not occur during dyeing, the dye is smoothly adsorbed and diffused into the interior, and the surface fastness is small, so that the fastness to friction hardly decreases.

The oxygen-free dyeing liquid referred to in the present invention is defined as a method in which an inert gas or a reactive gas is introduced into oxygen-containing air in a gas phase of a dyeing machine while circulating the dyeing liquid. Pressurization is performed, followed by degassing to replace air with another gas and transfer dissolved oxygen contained in the staining solution to the gas phase. By repeating this pressurization-deaeration operation several times, the dissolved oxygen in the dyeing solution is substantially absent.
The oxygen-free staining solution thus obtained is meant.

The other gases used here, ie, the inert gas or the reactive gas, include, for example, nitrogen gas, argon gas, helium gas, ammonia gas, sulfur dioxide gas, etc. Considering the above, nitrogen gas is optimal.

Hydrosulfite (Na ₂ S ₂ O ₄ ) is usually used as a reducing agent for vat dyes, but other thiourea dioxide, Rongalite, etc. may be used.
Examples of the alkali agent include sodium hydroxide, potassium hydroxide, and sodium phosphate, and sodium hydroxide is most suitable in consideration of price and the like.

After the vat dye is uniformly adsorbed on the fiber as a water-soluble leuco salt in such an atmosphere, an oxidizing agent is introduced into the can of the dyeing machine in an oxygen-free state to uniformly oxidize. To return the dye to an insoluble state in water. Examples of the oxidizing agent include hydrogen peroxide and sodium perborate.

[0017]

EXAMPLES The method of the present invention will be described more specifically with reference to the following examples. [Example 1] A knitted fabric was prepared by knitting a 50-thread single yarn of cotton with a 24-gauge double knitting machine using a smooth knitting machine, scouring and relaxing by a usual method, and drying and finishing. Using a reel wind type winder, the edge is trimmed on a perforated cylinder (beam tube) and uniformly wound. Set in the beam dyeing machine, cover and fix to the can.

Next, the dye Mikethren Blue
A staining solution adjusted to BC 1.5% owf is prepared.

In the hydraulic beam dyeing machine, the inside of the can is filled with the staining solution, and the staining solution overflowing from the relief valve is sent to the expansion tank, and is again sent into the can by the pump. The dyeing solution is uniformly circulated from the inside to the outside of the article to be dyed wound on the beam tube and dyed.

The dyeing method according to the present invention is performed in the following order. 1. The beam dyeing machine on which the object is fixed is filled with water. The pressure in the can was adjusted to 1.0-6.0 kg / by adjusting the pressure of the relief valve while circulating the previously prepared staining solution.
Press to cm ² . The dyeing solution overflowing from the relief valve is returned to the expansion tank, and is sent again into the can by a pressure pump.

2. Cover the expansion tank and introduce nitrogen gas into the gas phase of the tank.
Pressurize to 0 kg / cm ² . While maintaining the state, the dyeing solution in the can is circulated for 2 to 30 minutes while the dyeing solution is fed into the can by a pressure pump, and then degassed. At this time, the air in the gas phase portion in the expansion tank is replaced, and the dissolved oxygen in the staining solution moves to the gas phase portion. In addition, the dissolved oxygen contained in the staining solution coming out of the relief valve due to the pressure difference between the pressure in the can body and the pressure in the expansion tank is transferred to the gas phase in the expansion tank, and the oxygen-free staining solution is removed. Become.

3. Next, the lid of the expansion tank is opened, a dispersant, a leveling agent, an alkali agent, and the like are sequentially added to the dyeing solution, and the dyeing solution is sent into the can by a pressure pump to circulate the dyeing solution.

4. Thereafter, a reducing agent is added to the dyeing solution from the expansion tank, and the reducing agent is sent into the can with a pressure pump to circulate the dyeing solution. The lid of the expansion tank is closed again, and an inert gas or a reactive gas is introduced into the tank and pressurized to 1 to 5 kg / cm ² . Degas after circulating for 5-20 minutes while maintaining this state. By repeating this operation several times, the dissolved oxygen in the staining solution is completely eliminated, and the oxygen-free staining solution is obtained.

5. After circulating for 5-20 minutes while maintaining this state, the temperature is raised to 60 ° C. over 10-30 minutes and maintained for 30-60 minutes.

6. After that, cool the dyeing solution to near room temperature, open the lid of the expansion tank, add an appropriate amount of hydrogen peroxide solution as an oxidizing agent to the dyeing solution in this tank, and keep the dyeing machine closed and pressurized with a pressure pump again. Send in. 7. After the oxidation treatment, the inside of the dyeing machine is returned to atmospheric pressure, washed with water,
Perform soaping.

8. Result The fabric was fixed to the dyeing machine in the open state, and after the dyeing treatment and reduction treatment were performed in the oxygen-free dyeing solution, the oxidation treatment was continuously performed. was gotten. That is, a dyed cloth of uniform quality was obtained, which was free from irregularities such as spots, reduction spots, and oxidation spots, and did not have a hue difference between the inner and outer layers of the cloth wound around a beam tube or the like.

Further, the dye had good adsorbability and excellent color development. Since oxygen was not present in the gaseous phase and the liquid phase, there was no fluctuation in hue due to variation in consumption of the reducing agent, and the reproducibility was excellent (color difference ΔE = 0.5 or less).

No oxidation condensate was generated in the oxidation treatment step, and no impurities were observed on the dyed fabric and the inner wall of the dyeing machine. Therefore, the wet rub fastness of the material to be dyed was good.

[Comparative Example 1] Dyeing was carried out by a method in which oxygen was replaced with an inert gas (nitrogen gas) using a liquid jet dyeing machine. Was. Oxidation spots caused by air introduction during overflow drainage were also observed.

Oxygen in the gas phase occupying 2/3 of the dyeing machine and dissolved oxygen in the dyeing solution were not completely replaced by inert gas, and poor color reproducibility due to variation in the amount of reducing agent used was observed (color difference). ΔE = 1.0 or more). Oxidation condensate adhered near the gas-liquid boundary on the inner wall of the dyeing machine due to the introduction of air at the time of overflow drainage.

[Comparative Example 2] Based on the technical data of BASF, a large amount of reducing agent was charged to reduce oxygen in the liquid jet dyeing machine. Although the reducing agent was previously excessively added to the dyeing solution, it was not sufficient, and it was also consumed by the dissolved oxygen in the dyeing machine.

The oxidation treatment was carried out in a two-stage system including a gentle primary oxidation by overflow water injection and a secondary oxidation by injection of an oxidizing agent. However, unstable and poor color reproducibility were observed (color difference ΔE = 1.0). that's all). Oxidation condensate was generated in water during overflow injection. The decrease in wet rub fastness, which is considered to be caused by this, was observed in the material to be dyed.

[0033]

According to the present invention, when dyeing a fabric containing cellulose fibers with a vat dye, the material to be dyed is fixed in an oxygen-free dyeing medium, and the reduction dyeing and the oxidizing treatment are continuously performed. Unnecessary partial oxidation does not occur, the reducing agent works efficiently and effectively, and there is no contamination of the dye can. Therefore, as a result of the remarkable improvement in adsorption, uniform dyeing can be achieved, reproducibility is good, and color development is excellent. Further, since the partial oxide does not adhere to the fiber surface, the fastness to friction is also improved.

Claims (2)

[Claims] When dyeing a fabric containing cellulose fibers with a vat dye, the material to be dyed is fixed in a dyeing solution so as not to come into contact with the wall of a can body of the dyeing machine. , A reduction treatment is performed, and then an oxidizing agent is added while maintaining the oxygen-free state to perform an oxidation treatment. 2. The dyeing method according to claim 1, wherein a beam dyeing machine is used as a dyeing machine when dyeing a fabric containing cellulose fibers with a vat dye.