Dyeing method for cellulosic fiber product

Abstract

To provide a novel dyeing method that uses alkali washing under specific temperature and pH conditions, thereby enabling the production of a cellulosic fiber product dyed with a reactive dye, having high color fastness, and being free from hydrolysis during alkali treatment, while reducing CO2 emissions.SOLUTION: The present invention relates to a dyeing method for cellulosic fibers or for a fiber product containing cellulosic fibers, the method being a batch-type or continuous-type dyeing method and comprising the following: a dyeing reaction step in which the cellulosic fibers or fiber product containing the cellulosic fibers is reacted with a reactive dye in a dyeing solution; an alkali washing step in which, after all or part of the dyeing solution has been discharged, the dyed fibers or dyed fiber product is washed with an alkali washing solution having a pH of 10 to 14 and a temperature of 15 to 70°C; and an alkali post-washing step in which, after the alkali washing solution has been discharged, the fibers or fiber product is washed with water.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for dyeing cellulosic fibers or textile products containing cellulosic fibers using reactive dyes, and more particularly to a method for dyeing cellulosic fibers or textile products containing cellulosic fibers using reactive dyes, which method includes a specific washing step after the dyeing reaction step. [Background technology]

[0002] When reactive dyes are used in the industrial dyeing of cellulosic fibers or textile products containing cellulosic fibers, inorganic salts and alkaline agents are added to the dye bath as dyeing auxiliaries along with the reactive dye, and then the reactive dye is dyed. The presence of inorganic salts is necessary to promote the absorption of the dye into the cellulose fibers, while the alkaline agent is necessary to fix the reactive dye to the cellulose fibers. It is generally known that adding inorganic salts and alkaline agents to the dye bath is an important factor in obtaining uniformly dyed products. In dyeing using such reactive dyes, after the dyeing reaction is complete, unreacted dye and the inorganic salts and alkaline agents that serve as dyeing auxiliaries must be washed away. The reasons for this are as follows: If unreacted dye remains, there is a risk of color fading or dye contamination to other fabrics, i.e. poor color fastness. Inorganic salts have the role of absorbing dyes, so if the salt concentration is high, the dye itself cannot be removed. Alkali is irritating to the skin, so it is necessary to use an acid or other substance to lower the pH of the fabric and neutralize it.

[0003] Therefore, in the conventional washing method using reactive dyes, there is a problem that many washing steps must be carried out in order to prevent these chemicals from remaining on the dyed fabric. In conventional washing, high temperatures (generally around 90°C, but at least 75°C or higher) have been used to thoroughly remove the dye. Under these circumstances, steam generated by a boiler or other device is typically used to heat the large amounts of cleaning water used to high temperatures, which requires a lot of energy and time to heat up, which consumes a lot of electricity during operation and results in large CO2 emissions.

[0004] Patent Document 1 below proposes a washing method using an alkaline soaping bath for textile materials colored with reactive dyes having sulfate ethylsulfonyl groups, in which washing is performed with a washing solution having a temperature of 75 to 95°C, a pH of 9 to 10 for batch washing, and a pH of 9 to 12 for continuous washing. Furthermore, Patent Document 2 below describes that in dyeing cotton and cotton blend fabrics with reactive dyes, washing is carried out at 200°F (93.3°C) with a washing solution containing 0.25 to 1 g / L of an alkaline solution of 45 wt% KOH: 10 to 74 wt% and 50 Baume sodium silicate: 10 to 60 wt%. In this case, the pH of the washing solution is estimated to be around 11. Furthermore, Patent Document 3 listed below proposes a soaping agent suitable for washing at 70 to 75°C that provides the same effect as soaping performed at 90°C, and also proposes a treatment method in which washing is performed with a washing solution having a pH of 10 to less than 12 and containing a soaping agent containing a water-soluble salt of a polymerized fatty acid at 70 to 75°C. Furthermore, Patent Document 4 listed below proposes a treatment method for dyed products with disperse dyes and reactive dyes that are easily decomposed by alkali treatment, preferably nucleophilic substitution reactive dyes, in which the treatment is carried out at a pH of 8 or higher, preferably at a pH of 10.0 to 13.5, and at a temperature of 50 to 85°C, preferably at 60 to 80°C. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Unexamined Patent Publication No. 62-78287 [Patent Document 2] U.S. Patent No. 5,378,242 [Patent Document 3] Japanese Patent Application Publication No. 1-272888 [Patent Document 4] Japanese Unexamined Patent Publication No. 135383 [Non-patent literature]

[0006] [Non-Patent Document 1] Reference Material 2: List of formulas and emission factors for calculating greenhouse gas emissions (https: / / www.env.go.jp / earth / ondanka / suishin_g / 3rd_edition / ref2.pdf) Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the current state of the art described above, the problem that the present invention aims to solve is to provide a new method for dyeing cellulosic fiber fabrics, which can reduce CO2 emissions and produce cellulosic fiber products dyed with reactive dyes that have high color fastness and are not hydrolyzed by alkali treatment, by lowering the temperature of the washing solution and increasing the pH during washing after dyeing, particularly in a method for dyeing cellulosic fibers and products thereof using a nucleophilic addition reactive dye. In order to solve this problem, the inventors of the present application have investigated the possibility of lowering the temperature of washing water used in washing after dyeing cellulosic fibers and products thereof with reactive dyes, as described below.

[0008] As mentioned above, dyeing and finishing machines wash at high temperatures (generally around 90°C, but at least 75°C), which increases CO2 emissions due to the energy required to raise the temperature and the operating time required. On the other hand, if washing is carried out at a lower temperature, washing will not be sufficient, leading to poor colorfastness (fastness). As mentioned above, there is a technology that claims to improve dye fastness by washing with alkali. However, while alkali has the effect of improving the washing effect of dyes, it is also known that alkali further reacts with already reacted dyes, causing the bonds to be released, resulting in poor fastness, or hydrolyzing the dye itself, causing discoloration and fading. In Patent Document 1, washing is performed at a high temperature (75 to 95°C) at a pH of approximately 9 to 10 (immersion dyeing) or pH of 9 to 12 (continuous dyeing), but the effect obtained is not high, and even in such a relatively low pH range there is a risk of discoloration and poor fastness due to hydrolysis. Furthermore, treatment at such a relatively high temperature not only poses a risk of hydrolysis, but also produces CO2 emissions that are no different from those of conventional techniques. Furthermore, in Patent Document 2, washing is carried out at approximately 93°C and a pH of approximately 11, which increases the risk of discoloration and does not change the amount of CO2 emissions compared to the prior art. Furthermore, although Patent Document 3 claims a temperature of 75°C or lower, it states that the problem to be solved by the invention "demands" a "low temperature of 70 to 75°C," and does not anticipate lower temperatures than that. Washing at 70 to 75°C and pH 10 to 12 does not provide a significant effect, and even in this relatively low pH range, there is a risk of discoloration due to hydrolysis and poor fastness. Furthermore, although Patent Document 4 claims a temperature range of 50 to 80°C, all of the examples show washing at 80 to 85°C. Washing at 80 to 85°C and above pH 8 does not produce a significant effect, and even in this relatively low pH range there is a risk of discoloration and poor fastness due to hydrolysis, and CO2 emissions are not significantly improved compared to conventional techniques.

[0009] On the other hand, reactive dye species are classified into two types of reactive groups: "nucleophilic addition type" and "nucleophilic substitution type." It has been found that the "nucleophilic addition type" poses a particularly high risk of hydrolysis. [Means for solving the problem]

[0010] The present inventors have conducted extensive research and experiments to solve the above problems, and as a result have unexpectedly discovered that, in particular, in washing after dyeing in a method for dyeing cellulosic fibers and products thereof using a nucleophilic addition reactive dye, by lowering the temperature of the washing solution and increasing the pH, it is possible to reduce CO2 emissions, avoid hydrolysis of the dye due to alkali treatment, and obtain uniformly dyed products with high dye fastness and no color unevenness, and have completed the present invention.

[0011] That is, the present invention is as follows. [1] The following steps: A batch or continuous dyeing process comprising the following steps: a dyeing reaction step in which cellulose-based fibers or textile products containing cellulose-based fibers are reacted with a reactive dye in a dyeing solution; an alkaline washing step of washing the dyed fiber or textile product with an alkaline washing solution having a pH of 10 to 14 and a temperature of 15 to 70°C after discharging all or part of the dyeing solution; and an alkaline post-cleaning step of discharging the alkaline cleaning solution and then cleaning with water; A method for dyeing cellulosic fibers or textile products containing cellulosic fibers, comprising: [2] The dyeing method according to [1], wherein in the post-alkali washing step, an acid is added to the water and neutralized with an acid-containing pickling solution. [3] The dyeing method according to [1] or [2], further comprising an alkaline pre-washing step of washing with an aqueous solution between the dyeing reaction step and the alkaline washing step. [4] The dyeing method according to any one of [1] to [3], wherein the dyeing method is a batch dyeing method and the alkaline washing liquid has a pH of 10 to 13 and a temperature of 15°C to 70°C. [5] The dyeing method according to any one of [1] to [3], wherein the dyeing method is a continuous dyeing method and the alkaline washing liquid has a pH of 12 to 14 and a temperature of 15°C to 60°C. [6]The following formula (1): -0.07x+13≦y<-0.07x+17 The dyeing method according to any one of the above items [1] to [5], which satisfies the relationship: {wherein x is a temperature value of 15 to 70°C, and y is a pH value of 10 to 14.} [7] The dyeing method according to any one of [1] to [6], wherein the dyeing solution is maintained at a temperature of 5°C or higher and 70°C or lower throughout the alkaline washing step. [8] The dyeing method according to any one of [1] to [7] above, wherein the reactive dye comprises a nucleophilic addition reactive dye. [9] The dyeing method according to any one of [3] to [8], wherein in the alkaline pre-washing step, washing is carried out with water at a temperature of 5 to 70°C in a bath ratio of 1:100 or less.

[10] The dyeing method according to any one of [1] to [9], wherein in the alkaline washing step, washing is carried out with an alkaline washing liquid at a bath ratio of 1:100 or less and a temperature of 15 to 70°C.

[11] The dyeing method according to any one of [1] to

[10] , wherein in the post-alkali washing step, washing is carried out with water at a temperature of 5 to 70°C in a bath ratio of 1:100 or less. [Effects of the Invention]

[0012] According to the dyeing method of the present invention, in particular in the dyeing method for cellulosic fibers and products thereof using a nucleophilic addition reactive dye, by lowering the temperature of the washing liquid and increasing the pH during washing after dyeing, it is possible to obtain cellulosic fiber products dyed with reactive dyes that have high color fastness and are not hydrolyzed by alkali treatment while reducing CO2 emissions. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a liquid jet dyeing machine (an example of a batch-type washing device) that can be used in each washing step of the dyeing method of the present invention. [Figure 2] FIG. 1 is a schematic diagram of an open soaper type continuous washer (an example of a continuous batch type washing device) that can be used in each washing step of the dyeing method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail. One embodiment of the present invention is The following steps: A batch or continuous dyeing process comprising the following steps: a dyeing reaction step in which cellulose-based fibers or textile products containing cellulose-based fibers are reacted with a reactive dye in a dyeing solution; an alkaline washing step of washing the dyed fiber or textile product with an alkaline washing solution having a pH of 10 to 14 and a temperature of 15 to 70°C after discharging all or part of the dyeing solution; and an alkaline post-cleaning step of discharging the alkaline cleaning solution and then cleaning with water; The present invention relates to a method for dyeing cellulosic fibers or textile products containing cellulosic fibers, comprising the steps of:

[0015] The form of the cellulosic fibers or textile products containing cellulosic fibers to be dyed by the dyeing method of this embodiment is not particularly limited, and various forms such as yarn, woven fabric, weft knitted fabric, nonwoven fabric, and sewn products can be used. The cellulosic fibers are also not particularly limited, and examples include cotton, linen, rayon, cuprammonium rayon, lyocell, organic solvent cellulose fibers, and ionic liquid cellulose fibers. Preferred are cotton, rayon, cuprammonium rayon, lyocell, and organic solvent cellulose fibers, and more preferred are cotton, rayon, and cuprammonium rayon. Fibers other than the cellulosic fibers in textile products containing cellulosic fibers to be dyed by the dyeing method of this embodiment can be dyed in combination with known dyeing methods.

[0016] The dyeing method of the present embodiment is not particularly limited and may be either textile printing or plain dyeing, but is preferably plain dyeing. Examples of the dye reaction step in the dyeing method of the present embodiment include a pad steaming method, a pad batch method, and a dipping method, but are not particularly limited to these.

[0017] The equipment used in each washing step of the dyeing method of this embodiment may be of a batch type or a continuous type and is not particularly limited, but as batch types, preferred are a cheese dyeing machine, a hank dyeing machine, a liquid jet dyeing machine, an air jet dyeing machine, a beam dyeing machine, a jigger dyeing machine, a winch dyeing machine, a rotary dyeing machine, a paddle dyeing machine, and a minicolor dyeing machine, and more preferred are liquid jet dyeing machines (see FIG. 1).As continuous types, preferred are an open soaper type continuous washer and a continuous winch dyeing machine, and more preferred are an open soaper type continuous washer (see FIG. 2).

[0018] The reactive dye used in the dyeing method of this embodiment is preferably, for example, a reactive dye having a nucleophilic addition reactive group, or a bifunctional or polyfunctional reactive dye having nucleophilic addition and nucleophilic substitution reactive groups. Examples of the nucleophilic addition reactive group include saturated alkane monocarboxylic acid amides, saturated alkane dicarboxylic acid amides, saturated alkane monocarboxylic acids, cycloalkane carboxamides, alkene monocarboxamides, alkene dicarboxyamides, saturated aliphatic ketones, saturated aliphatic sulfonic acid amides, vinyl sulfamides, β-saturated ethyl sulfones, vinyl sulfones, and sulfate ethyl sulfonic acid reactive groups, with vinyl sulfone and sulfate ethyl sulfonic acid reactive groups being preferred. Examples of the nucleophilic substitution reactive group include pyridine-based, pyridazine-based, pyridazone-based, pyrimidine-based, S-triazine-based, 1,2,4-triazine-based, thiazole-based, benzoxazole-based, benzothiazole-based, quinoline-based, isoquinoline-based, quinoxaline-based, quinazoline-based, and phthalazine-based reactive groups, with 1,2,4-triazine-based being preferred.

[0019] Inorganic salts used in the dyeing reaction method include, but are not limited to, sodium sulfate, potassium sulfate, sodium chloride, potassium chloride, and mixtures thereof. Alkaline agents include, but are not limited to, sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium metasilicate, trisodium phosphate, tripotassium phosphate, and mixtures thereof.

[0020] The dyeing method of the present embodiment includes the reactive dyeing step, the alkaline washing step for removing the remaining dye and the like after the dyeing solution is discharged from the dye bath, and the post-alkaline washing step for performing washing after the alkaline washing solution is discharged.

[0021] (Alkaline cleaning process) The alkaline washing step will be described in detail below. The dyeing method of the present embodiment is a batch or continuous dyeing method comprising the following steps: a dyeing reaction step in which cellulose-based fibers or textile products containing cellulose-based fibers are reacted with a reactive dye in a dyeing solution; an alkaline washing step of washing the dyed fiber or textile product with an alkaline washing solution having a pH of 10 to 14 and a temperature of 15 to 70°C after discharging all or part of the dyeing solution; and an alkaline post-cleaning step of discharging the alkaline cleaning solution and then cleaning with water; The present invention relates to a method for dyeing cellulosic fibers or textile products containing cellulosic fibers, comprising the steps of: The alkaline washing step is a step in which, by lowering the temperature of the washing solution and increasing the pH, it is possible to obtain a cellulosic fiber product dyed with a reactive dye that has high color fastness and is not hydrolyzed by alkaline treatment, while reducing CO2 emissions. A single treatment is preferred from the viewpoint of using less alkali and thus reducing the burden on wastewater, but multiple washing treatments may be included.

[0022] The alkaline cleaning solution is an aqueous solution containing one or more alkalis, having a pH of 10 to 14 and a temperature of 15 to 70° C., and can be selected from the viewpoints of ease of hydrolysis of the dye used, cleaning treatment time, and the required wet fastness, and from the viewpoints of CO2 emissions and the fact that the higher the temperature, the greater the risk of hydrolysis, the pH is preferably 15 to 60° C., more preferably 15 to 50° C. Furthermore, a higher pH range makes it easier to control the addition of alkali and improves cleaning performance, so the pH is preferably 10.5 to 14, more preferably 11 to 14.

[0023] The alkaline cleaning solution is preferably an aqueous solution having a pH of 10 to 13 and a temperature of 15 to 70°C, since batch processing requires a long processing time and increases the risk of hydrolysis. On the other hand, continuous processing requires a short processing time and increases the risk of insufficient cleaning, while high temperatures can generate alkali-containing vapor, which can be dangerous to the work. Therefore, the alkaline cleaning solution is preferably an aqueous solution having a pH of 12 to 14 and a temperature of 15 to 60°C.

[0024] Furthermore, in order to eliminate the influence of hydrolysis caused by a high-temperature alkaline cleaning solution and to eliminate insufficient cleaning caused by a low-temperature alkaline cleaning solution, the alkaline cleaning solution preferably has a structure represented by the following formula (1): -0.07x+13≦y<-0.07x+17 The aqueous solution satisfies the relationship: {wherein x is a temperature value of 15 to 70°C, and y is a pH value of 10 to 14.}

[0025] The alkaline cleaning solution may contain components such as a dispersant, a wetting agent, an in-bath softener, an in-bath smoothing agent, an emulsifier, a soaping agent, etc., as desired. The alkali contained in the alkaline cleaning solution is not particularly limited, and examples thereof include sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium metasilicate, trisodium phosphate, tripotassium phosphate, and mixtures thereof, and is preferably sodium carbonate, potassium carbonate, sodium hydroxide, or potassium hydroxide, and more preferably sodium carbonate or sodium hydroxide.

[0026] (Post-alkali cleaning process) The post-alkali cleaning method will be described in detail below. The dyeing method of the present embodiment includes an alkaline post-washing step in which, after all or part of the alkaline washing liquid is discharged, a post-alkaline washing liquid is added for washing. The post-alkali cleaning step is a step in which the fabric is treated with water, which is the post-alkali cleaning solution, in order to wash away the alkali used in the alkaline cleaning solution. A single treatment may be performed, but it is preferable to include multiple cleaning treatments, since residual alkali may cause serious complaints such as skin disorders or may inhibit the functional processing in the subsequent finishing step.

[0027] The temperature of the water used as the post-alkali cleaning liquid is preferably 5°C to 70°C, more preferably 5°C to 50°C, from the viewpoint of reducing CO2 emissions by keeping the temperature low. However, since low temperatures are easily affected by air temperature, the temperature is even more preferably 15°C to 50°C.

[0028] An acid may be added to the water serving as the post-alkali cleaning solution to eliminate any residual alkali, and the acid to be used is not limited, and may be any of citric acid, malic acid, acetic acid, formic acid, sulfuric acid, nitric acid, hydrochloric acid, oxalic acid, etc., but is preferably one that is less corrosive to metals, more preferably formic acid, acetic acid, citric acid, or malic acid. Furthermore, the water serving as the post-alkali cleaning solution may optionally contain components such as a dispersant, a wetting agent, a bath softener, a bath smoothing agent, an emulsifier, and a soaping agent.

[0029] (Alkaline pre-cleaning process) An alkaline pre-washing step of washing with an aqueous solution may be carried out between the dyeing reaction step and the alkaline washing step. The addition of an alkaline pre-washing step is desirable from the viewpoint of being able to eliminate high concentrations of salts that have a dye exhaustion effect and to enhance the washing effect of the alkaline washing step.

[0030] The water that is the alkaline pre-washing liquid is not particularly limited, and may contain components such as a dispersant, a wetting agent, an in-bath softener, an in-bath smoothing agent, an emulsifier, and a soaping agent, as desired. However, water is preferred from the viewpoint of excluding salts.

[0031] The temperature of the water serving as the alkaline pre-washing solution is preferably 5°C to 70°C, more preferably 5°C to 50°C, from the viewpoint that CO2 emissions can be reduced by keeping the temperature low. However, since a low temperature makes the water susceptible to the influence of air temperature and makes it difficult to perform stable dyeing, the temperature is even more preferably 15°C to 50°C.

[0032] The liquor ratios for the alkaline washing step, post-alkaline washing step, and pre-alkaline washing step depend on the washing machine, and when a continuous washing machine is used to process a large amount of material, the liquor ratio will be higher than 1:1. As the liquor ratio increases, the amount of CO2 emitted due to the temperature rise of the washing solution increases, so the liquor ratio is preferably 1:100 or less, and more preferably 1:30 or less. [Example]

[0033] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The calculation of CO2 emission reductions and various evaluations of each yarn or textile product in the examples were carried out using the following methods.

[0034] (1) Calculation of CO2 emissions The amount of electricity consumed and steam consumed in the operation of the dyeing machine were measured and calculated using the following formula: W=E×α+S×β The CO2 emissions (kg-CO2e) were calculated using the formula: {W: CO2 emissions (kg-CO2e), E: power consumption (MJ), S: steam consumption (MJ), α: CO2 intensity of electricity (kg-CO2e / MJ), β: CO2 intensity of steam (kg-CO2e / MJ).} Here, α and β are the CO2 intensity of electricity and steam (kg-CO2e / MJ) at a certain point in time, and are values published by the Ministry of the Environment. The CO2 intensity at a certain point in time is not particularly limited, but can be calculated using the formula: Examples of CO2 emissions per unit of production are listed in the "List of Calculation Formulas and Emission Factors for Calculating Greenhouse Gas Emissions" (https: / / www.env.go.jp / earth / ondanka / suishin_g / 3rd_edition / ref2.pdf). For example, the unit of production for electricity, α, is 0.1542 (kg-CO2e / MJ), and the unit of production for steam, β, is 0.0600 (kg-CO2e / MJ). In the following examples, CO2 emissions (kg-CO2e) were calculated using the unit of production, α = 0.1542 (kg-CO2e / MJ), and β = 0.0600 (kg-CO2e / MJ). Among the comparative examples for each dyeing method, material type, and dye usage, the one using the conventional water washing method was used as the "blank." If the CO2 emissions (kg-CO2e) decreased compared to the blank, it was judged as "improved," and if there was no change, it was rated as "same."

[0035] (2) Color fading The dyed textile products were measured using a spectrophotometer (Gretagmacbeth, Model Color-Eye7000A) under conditions of D56 light source and a viewing angle of 10 degrees, and the L* value in the CIE1976 L*a*b* color space was calculated. In addition, among the comparative examples of each dyeing method, material type, and dye usage, the one using the conventional water washing method was used as a "blank", and the L* value was calculated using the following formula: ΔL* value = L* value of blank - L* value of sample The ΔL* value was calculated. When the ΔL* value was 0.5 or less, there was no color fading and it could be judged as good. When the ΔL* value was more than 0.5 and less than 1.0, it was judged as "slightly worse," and when it was more than 1.0, it was judged as "worsened."

[0036] (3) Sweat fastness The sweat fastness test was conducted in accordance with the test method for dye fastness to sweat specified in JIS L 0848. Furthermore, a multi-fiber mixed fabric woven in a vertical stripe pattern with eight types of fibers (cotton, nylon, acetate, wool, rayon, acrylic, silk, and polyester) conforming to JIS L 0803 was used as the attached white cloth. Furthermore, among the comparative examples for each dyeing method, material type, and dye usage, one that used the conventional water washing method was used as the "blank." The total of the acidic sweat fastness and alkaline sweat fastness was compared to the blank, with a larger number being "improved," the same being "same," and a smaller number being "worse."

[0037] (4) Items to be dyed Furthermore, cupra knitted fabrics and cotton knitted fabrics were used as the substrates for dyeing in the examples and comparative examples. They were obtained as follows: The cupra knit fabric was prepared as follows. Using a 24-gauge single-end test cylinder knitting machine (model NCR-ES, manufactured by Eiko Sangyo Co., Ltd.), 5 parts of 167 dtex cupra fiber, a regenerated cellulose fiber, were knitted in a bath containing 0.1 parts of sodium carbonate and 0.1 parts of the surfactant Scoreol (manufactured by Kitahiro Chemical Co., Ltd.) dissolved in 100 parts of water, treated at a liquid temperature of 90°C for 30 minutes, then dehydrated and dried to obtain a dyed cupra knitted fabric. The cotton knit fabric was prepared as follows. A general-purpose smooth knitted fabric made of cotton was scoured and bleached to obtain a pre-dyeing unmercerized cotton knitted fabric, which was used as the material to be dyed. The cupro fabric was prepared as follows. A pre-dyed cupra fabric was obtained by scouring a woven fabric made by weaving a warp thread of 84 dtex cupra fiber and a weft of 110 dtex cupra fiber on a loom, and this was used as the material to be dyed.

[0038] [Comparative Example 1a] Dyeing process: Dyeing was performed using a batch-type mini-color dyeing machine (UR·MINI-COLOR model, manufactured by Texam Giken Co., Ltd.). First, the dyeing reaction process was carried out. 140 parts of 20°C water was placed in a stainless steel pot with a diameter of 72 mm and a height of 110 mm, and 5 parts of cupra knit fabric were added as the substrate. Then, a total of 5 parts of reactive dyes with nucleophilic addition reactive groups (0.125 parts of Remazol BrRed BB 150% (manufactured by Dystar Japan Co., Ltd.), 0.0625 parts of Remazol BrYellow GL 150% (manufactured by Dystar Japan Co., Ltd.), and 0.0625 parts of KPZOL BLACK B 150 POWDER (manufactured by Kiwa Chemical Industry Co., Ltd.)) were added. Thereafter, the liquid temperature was raised to 60°C, and 7.5 parts of sodium sulfate was added to exhaust the dye. Then, 2.25 parts of sodium carbonate was added, and the liquid was kept at 60°C for 30 minutes to react with the dye. Thereafter, 120 parts of the dyeing liquid was taken out to obtain a dyed product before the washing step. Next, a total of four washing steps were performed. The temperature was increased in each step under the conditions of an initial temperature of 15°C and a temperature increase rate of 3°C / min. The initial temperature and the temperature increase rate were the same in all of the following Examples and Comparative Examples. First washing step: 70 parts of water was added, the temperature was raised to 20° C., and washing was carried out by maintaining the temperature for 10 minutes, and then 70 parts of the washing liquid was taken out. Second washing step: 70 parts of a solution prepared by dissolving 0.25 parts of acetic acid in water was added, and the temperature was raised to 20° C., followed by maintaining the temperature for 10 minutes to carry out washing, after which 70 parts of the washing solution was taken out. Third washing step: 70 parts of water was added, the temperature was raised to 90° C., and washing was carried out by maintaining the temperature for 10 minutes, and then 70 parts of the washing liquid was taken out. Fourth washing step: 70 parts of water was added, the temperature was raised to 20°C, and the mixture was kept for 10 minutes for washing. The dyed fabric was then taken out and dehydrated and dried by a known method to obtain a dyed product after the washing step. The dyed products after the washing process were evaluated for color fading and sweat fastness. CO2 emissions during the dyeing and washing processes were also calculated.

[0039] [Comparative Examples 1b-1c, Examples 1a-1d] Dyeing step: Five parts of a cupra knit fabric were dyed using the dye and method of Comparative Example 1a, and the solution was removed to obtain a dyed product before the washing step. Next, in the washing step, the washing liquid and temperature were changed as shown in Table 1 below, and washing, dehydration and drying were carried out in the same procedure as in Comparative Example 1a to obtain dyed products after the washing step. The evaluations of color fading, sweat fastness, and CO2 emissions were compared with those of Comparative Example 1a. The comparison results are summarized in Table 2 below.

[0040] [Comparative Examples 2a and 2b, Examples 2a and 2b] Dyeing step: The dye was reacted using the same dye and method as in Comparative Example 1a, except that 5 parts of a cotton knitted fabric was used as the material to be dyed, and the solution was removed to obtain a dyed product before the washing step. Next, in the washing step, the washing liquid and temperature were changed as shown in Table 1 below, and washing, dehydration and drying were carried out in the same procedure as in Comparative Example 1a to obtain dyed products after the washing step. The evaluation and comparison results for color fading, sweat fastness, and CO2 emissions are summarized in Table 2 below.

[0041] [Comparative example 3a] Dyeing step: The dye was reacted in the same manner and by the same method as in Comparative Example 1a, except that the material to be dyed was changed to 5 parts of cotton knitted fabric, and the solution was removed to obtain a dyed product before the washing step. Next, as a washing step, washing treatment was carried out a total of six times. First washing step: 70 parts of water was added, the temperature was raised to 20° C., and washing was carried out by maintaining the temperature for 10 minutes, and then 70 parts of the washing liquid was taken out. Second washing step: 70 parts of a solution prepared by dissolving 0.4 parts of acetic acid in water was added, and the temperature was raised to 30° C., followed by maintaining the temperature for 10 minutes to carry out washing, after which 70 parts of the washing solution was taken out. Third washing step: 70 parts of a liquid containing 0.2 parts of soaping agent Maysanol KHM (Meisei Chemical Industry Co., Ltd.) was added, the temperature was raised to 90°C, and the mixture was maintained for 10 minutes to wash, after which 70 parts of the washing liquid was removed. Fourth washing step: 70 parts of water was added, the temperature was raised to 20° C., and washing was carried out by maintaining the temperature for 10 minutes, and then 70 parts of the washing liquid was taken out. Fifth washing step: 70 parts of water was added, the temperature was raised to 20° C., and washing was carried out by maintaining the temperature for 10 minutes, and then 70 parts of the washing liquid was taken out. Sixth washing step: 70 parts of water was added, the temperature was raised to 20°C, and the mixture was held for 10 minutes to wash. The dyed fabric was then removed and dehydrated and dried by a known method to obtain a dyed product after the washing step. The dyed products after the washing process were evaluated for color fading and sweat fastness. CO2 emissions during the dyeing and washing processes were also calculated.

[0042] [Comparative Examples 3b-3d, Examples 3a-3g] Dyeing step: 5 parts of a cotton knitted fabric was reacted with the dye using the dye and method of Comparative Example 1a, and the solution was removed to obtain a dyed product before the washing step. Next, in the washing step, the washing liquid and temperature were changed as shown in Table 1 below, and washing, dehydration and drying were carried out in the same procedure as in Comparative Example 3a to obtain dyed products after the washing step. The evaluations of color fading, sweat fastness, and CO2 emissions were compared with those of Comparative Example 3a. The comparison results are summarized in Table 2 below.

[0043] [Comparative Example 4a, Examples 4a and 4b] Dyeing process: 5 parts of cupra knit fabric are used as the dyeing material, The dyes were reacted in the same manner as in Comparative Example 1a, except that a total of 0.25 parts of reactive dyes having a nucleophilic addition reactive group and a nucleophilic substitution reactive group (0.125 parts of Remazol Red RGB (manufactured by Dystar Japan Co., Ltd.), 0.0675 parts of Remazol GoldYellow RGB (manufactured by Dystar Japan Co., Ltd.), and 0.0675 parts of Remazol Navy RGB (manufactured by Dystar Japan Co., Ltd.)) were used, and the liquid was removed to obtain a dyed product before the washing step. Next, in the washing step, the washing liquid and temperature were changed as shown in Table 1 below, and washing, dehydration and drying were carried out in the same procedure as in Comparative Example 1a to obtain dyed products after the washing step. The evaluation and comparison results for color fading, sweat fastness, and CO2 emissions are summarized in Table 2 below.

[0044] [Comparative Examples 5a-5c, Examples 5a and 5b] Dyeing step: 5 parts of a cotton knit fabric was reacted with the dye using the dye and method of Comparative Example 4a, and the solution was removed to obtain a dyed product before the washing step. Next, in the washing step, the washing liquid and temperature were changed as shown in Table 1 below, and washing, dehydration and drying were carried out in the same procedure as in Comparative Example 3a to obtain dyed products after the washing step. The evaluation and comparison results for color fading, sweat fastness, and CO2 emissions are summarized in Table 2 below.

[0045] [Comparative Example 6a] Dyeing process: Pad steam dyeing was performed as a continuous dyeing method. First, the dyeing reaction process was carried out. 10 parts of cupra fabric were immersed in 100 parts of an aqueous solution containing 5 parts of Remazol BrRed BB 150% (manufactured by Dystar Japan Co., Ltd.), a reactive dye with nucleophilic addition reactive groups, 5 parts of sodium sulfate, and 1 part of sodium hydroxide. The padding process, in which the fabric was squeezed to an 80% pickup rate using a mangle, was repeated twice with the same solution. Next, using a press machine applicable to the JIS L1096H method for measuring dimensional change in presses, the test specimen and filter paper were placed on the lower iron. The upper iron was lowered 20 mm above the test specimen, and steaming was performed with 490 kPa steam set at 100 °C for 90 seconds. This completed the dyeing reaction process and yielded the dyed fabric ready for the washing process. Next, as a washing step, washing treatment was carried out a total of five times. First washing step: After immersion in 100 parts of water heated to 30°C for 10 seconds, the fabric was squeezed with a mangle to a pickup rate of 80%, and then washed twice with the same solution. Second washing process: The fabric was soaked for 10 seconds in 100 parts of an aqueous solution containing 0.02 parts of citric acid heated to 80°C and 0.02 parts of soaping agent Maysanol KHM (Meisei Chemical Industry Co., Ltd.), and then squeezed with a mangle to a pickup rate of 80%, and washed twice with the same solution. The third washing step was carried out in the same manner as the second washing step. Fourth washing step: After immersion in 100 parts of water heated to 30°C for 10 seconds, the fabric was squeezed with a mangle to a pickup rate of 80%, and then washed twice with the same solution. The fifth washing step was carried out in the same manner as the fourth washing step. Finally, the washing step was carried out by a known method to obtain a dyed product after the washing step.

[0046] Example 6b Dyeing step: 10 parts of cupra fabric were dyed as the object to be dyed using the same dye and method as in Example 6a to obtain a dyed product before the washing step. Next, in the washing step, the washing liquid and temperature were changed as shown in Table 1 below, and washing, dehydration and drying were carried out in the same procedure as in Comparative Example 6a to obtain dyed products after the washing step. The evaluations of color fading, sweat fastness, and CO2 emissions were compared with those of Comparative Example 6a. The comparison results are summarized in Table 2 below.

[0047] [Table 1]

[0048] [Table 2]

[0049] In Comparative Examples 1a to c and Examples 1a to d, which are sample groups using a batch dyeing method, a cupra knit fabric as the dyeing material, a nucleophilic addition reactive dye as the dye type, and four washes, it can be confirmed that in all of Examples 1a to d, there is no hydrolysis, sweat fastness is improved, and the amount of CO2 emissions is reduced, compared to Comparative Example 1a, which does not use alkaline washing. In Comparative Example 1b, which does not include alkaline washing, low-temperature dyeing is performed, but the results are worse than in Comparative Example 1a. In Comparative Example 1c, although there is an alkaline washing step, the temperature range is 90°C, which causes hydrolysis, fades the color, and deteriorates the fastness.

[0050] In Comparative Examples 2a-b and Examples 2a-b, which are sample groups using a batch dyeing method, cotton knit fabric as the substrate, a nucleophilic addition reactive dye as the dye, and four washes, Example 2a shows no hydrolysis, improved sweat fastness, and reduced CO2 emissions compared to Comparative Example 2a, which does not use alkaline washing.In Example 2b, the temperature was 70°C and pH was 11, and CO2 emissions were reduced and fastness was the same, but color fading due to hydrolysis was observed. In Comparative Example 2b, although an alkaline washing step is performed, the temperature range is 90° C. and the pH range is as low as 9.4, but the fastness deteriorates due to hydrolysis.

[0051] In Comparative Examples 3a-d and Examples 3a-g, which are sample groups using a batch dyeing method, cotton knit fabric as the substrate, a nucleophilic addition reactive dye as the dye, and six washes, Examples 3a, c, d, f, and g show no hydrolysis, improved sweat fastness, and reduced CO2 emissions compared to Comparative Examples 3a and 3b, which do not use alkaline washing. In Example 3b, which was 70°C and pH 12.5, and in Example 3e, which was 50°C and pH 13.6, color fading due to hydrolysis was observed, but CO2 emissions were reduced. In Comparative Example 3b, there was no alkaline washing step and the temperature range was 70°C. Although CO2 emissions were reduced compared to Comparative Example 3a, fastness deteriorated due to insufficient washing. In Comparative Example 3c, although an alkaline washing step was performed, the pH was 14.2 at 30°C, exceeding pH 14. Although CO2 emissions were reduced compared to Comparative Example 3a, fastness was significantly deteriorated due to hydrolysis. In Comparative Example 3d, although an alkaline washing step was performed, the temperature was 60°C and the pH was 9.8, which was below pH 10. Although the CO2 emissions were reduced compared to Comparative Example 3a, the fastness was significantly deteriorated due to insufficient washing.

[0052] In Comparative Example 4a and Examples 4a-b, which are a group of samples using a batch dyeing method, a cupra knit fabric, a reactive dye with both nucleophilic addition and nucleophilic substitution reactive groups, and four washes, Example 4a shows no hydrolysis, improved sweat fastness, and reduced CO2 emissions compared to Comparative Example 4a, which did not undergo alkaline washing.In Example 4b, which was immersed at 60°C and pH 13.1, color fading due to hydrolysis was observed, but CO2 emissions were reduced.

[0053] In Comparative Examples 5a-c and Examples 5a-b, which are sample groups using a batch dyeing method, a cotton knitted fabric as the dyeing target, a reactive dye having both nucleophilic addition and nucleophilic substitution reactive groups as the dye type, and six washes, it can be confirmed that in both Examples 5a and 5b, there is no hydrolysis, sweat fastness is improved, and the amount of CO2 emissions is reduced, compared to Comparative Example 5a, which does not use alkaline washing. In Comparative Example 5b, although an alkaline washing step was performed, the temperature was 30°C and the pH was 14.4, which is higher than pH 14. Although CO2 emissions were reduced compared to Comparative Example 3a, fastness was significantly deteriorated due to hydrolysis. In Comparative Example 5c, although an alkaline washing step was performed, the temperature was 60°C and the pH was 9.8, which was below pH 10. Although CO2 emissions were reduced compared to Comparative Example 3a, fastness was significantly deteriorated due to insufficient washing.

[0054] In Comparative Example 6a and Example 6a, which are sample groups using a continuous dyeing method, cupra fabric as the dyeing material, a nucleophilic addition reactive dye as the dye type, and five washes, Example 6a shows no hydrolysis and has the same sweat fastness as Comparative Example 6a, which does not have alkaline washing, and it can be confirmed that the amount of CO2 emissions has been reduced. [Industrial Applicability]

[0055] The present invention provides a novel dyeing method that can reduce CO2 emissions and obtain cellulosic fiber products dyed with reactive dyes that have high color fastness and are not hydrolyzed by alkali treatment, by lowering the temperature of the washing solution and increasing the pH during washing after dyeing, particularly in a method for dyeing cellulosic fibers and products thereof using a nucleophilic addition reactive dye. Therefore, the present invention can be suitably used in the dyeing of cellulosic fibers and products thereof using reactive dyes. [Explanation of symbols]

[0056] 1 Jet dyeing machine 2 reserve tank 3 Heat exchanger 4 nozzles 5. Fabric 6 Dye bath 7. Reaction process machine: Pad steaming dyeing machine 8 Fabric before dyeing (reaction process, washing process) 9 Dye bath 10 Mangle 11 Steam Box 12 Washing process machine: Open soap type continuous water washer 13 Cylinder dryer 14 Fabric after dyeing (reaction process, washing process)

Claims

1. The following steps: A batch or continuous dyeing process comprising the following steps: a dyeing reaction step in which cellulose-based fibers or textile products containing cellulose-based fibers are reacted with a reactive dye in a dyeing solution; After the dyeing solution is completely or partially discharged, an alkaline washing step of washing the dyed fiber or textile product with an alkaline washing solution having a pH of 10 to 14 and a temperature of 15 to 70°C; and an alkaline post-cleaning step of discharging the alkaline cleaning solution and then cleaning with water; A method for dyeing cellulosic fibers or textile products containing cellulosic fibers, comprising:

2. The dyeing method according to claim 1, wherein in the post-alkali washing step, an acid is added to the water and neutralized with an acid-containing pickling solution.

3. The dyeing method according to claim 1 or 2, further comprising an alkaline pre-washing step of washing with an aqueous solution between the dyeing reaction step and the alkaline washing step.

4. The dyeing method according to claim 1 or 2, wherein the dyeing method is a batch dyeing method, and the alkaline washing solution has a pH of 10 to 13 and a temperature of 15°C to 70°C.

5. 3. The dyeing method according to claim 1, wherein the dyeing method is a continuous dyeing method, and the alkaline washing solution has a pH of 12 to 14 and a temperature of 15 to 60°C.

6. The following formula (1): -0.07x+13≦y<-0.07x+17 3. The dyeing method according to claim 1 or 2, wherein the following relationship is satisfied: {wherein x is a temperature value of 15 to 70° C., and y is a pH value of 10 to 14.}

7. 3. The dyeing method according to claim 1, wherein the dyeing solution is maintained at a temperature of 5°C or higher and 70°C or lower throughout the alkaline washing step.

8. The dyeing method according to claim 1 or 2, wherein the reactive dye comprises a nucleophilic addition reactive dye.

9. The dyeing method according to claim 3, wherein in the alkaline pre-washing step, washing is carried out with water at a liquor ratio of 1:100 or less and a temperature of 5 to 70°C.

10. The dyeing method according to claim 1 or 2, wherein in the alkaline washing step, washing is carried out with an alkaline washing solution at a bath ratio of 1:100 or less and a temperature of 15 to 70°C.

11. The dyeing method according to claim 1 or 2, wherein in the post-alkali washing step, washing is carried out with water at a liquor ratio of 1:100 or less and a temperature of 5 to 70°C.

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