A method for improving the dyeing lifting power of high-concentration reactive black 5 using PEG-400 based on a non-aqueous medium system

Abstract

The invention discloses a method for improving the dyeing lifting power of high concentration reactive black 5 using PEG 400 based on non-aqueous medium system, and belongs to the field of dyeing technology. The method of the present invention comprises the following steps: (1) cotton fabric, reactive black 5, water, NaOH, Na2CO3, PEG 400 and D5 are uniformly mixed to obtain a mixed system; (2) the mixed system is insulated, then heated up and kept incubated for a period of time, finally washed and dried to obtain dyed fabric. Using the method of the present invention, under the same dyeing conditions, when PEG 400 concentration is 3g / L, the K / S value (fabric color yield) of the reactive black 5 after dyeing in non-aqueous medium of higher concentration (> 3% (owf)) is larger than the dyed fabric K / S value without PEG 400, that is, after adding PEG 400, the dyeing lifting power of reactive black 5 in non-aqueous medium is improved.

Description

Technical Field

[0001] The invention relates to a method for improving the dyeing lifting power of high-concentration Reactive Black 5 by utilizing PEG-400 based on a non-aqueous medium system, and belongs to the technical field of dyeing processes. Background Art

[0002] Dye depth refers to the degree of color change in a fabric at different dye dosages. It can increase the depth of dyeing and enhance fabric durability. Dye lift is particularly important in dyeing dark and rich fabrics. Dye lift depends primarily on the degree of dye aggregation on the fiber surface, its diffusion rate into the fiber, and the rate of covalent bond reaction with the fiber. In traditional waterbath dyeing, reactive dyes are typically dyed in aqueous solution using water as the medium. Due to their high water solubility, reactive dyes distribute less in the fabric solid phase than in the aqueous phase. Therefore, during reactive dye waterbath dyeing, some dye remains in the aqueous phase and cannot be fully absorbed by the fiber, reducing the utilization rate of the reactive dye, with the fixation rate generally ranging from 60% to 80%. Furthermore, at higher dye concentrations, the reactive dye's low adsorption efficiency results in lower utilization and lift, reducing the dye's depth of application. Secondly, in order to reduce the loss rate of dyes and achieve a relatively high dyeing rate, it is usually necessary to add a large amount of neutral electrolytes to promote dyeing, especially in a large bath ratio dyeing environment; although the addition of neutral electrolytes increases the dyeing rate, it results in a high concentration of inorganic salts remaining in the dye liquor after dyeing, and these inorganic salts cannot be removed by simple physical and chemical methods, which increases the difficulty and cost of dyeing wastewater treatment; and the discharge of salt-containing dyeing wastewater leads to the mineralization of freshwater resources and soil alkalinization, which damages the ecological environment and is not conducive to ecological sustainable development.

[0003] When dyeing cotton fabric with reactive dyes in a non-aqueous system using decamethylcyclopentasiloxane (D5) as a medium, only a small amount of water is needed to swell the fabric and dissolve the reactive dye and alkali. This water mass is only 1-2 times that of the fabric being dyed. Water used for temperature control and dye-fabric exchange is replaced by the non-aqueous medium. Due to the fiber-loving and non-aqueous-acidic properties of the reactive dye, dye uptake can reach 100%. Furthermore, the short dyeing time and low temperature control significantly improve dye utilization, enabling salt-free and low-water dyeing of cotton fabric with reactive dyes. As the world's largest textile producer and exporter, China is increasingly interested in developing effective methods to improve reactive dye dyeing efficiency and reduce wastewater generation. Currently, little research has explored the dye-lifting properties of non-aqueous systems. Therefore, studying how to improve the utilization and dye-lifting properties of reactive dyes in non-aqueous systems is an important research direction.

[0004] Polyethylene glycol (PEG) is colorless, non-toxic, and non-irritating. It is obtained by anionic ring-opening polymerization of ethylene oxide with branched or linear polyethers terminated with hydroxyl groups. As the average molecular weight increases, the state gradually changes from a viscous liquid to a waxy solid. It has good chemical and thermal stability and is an environmentally friendly polymer compound. The molecular skeleton of polyethylene glycol is rich in hydrophilic groups, which easily form hydrogen bonds with water molecules and are highly soluble in water. In addition, polyethylene glycol also has excellent solubility, lubricity, moisture retention, dispersibility, and biocompatibility, and has shown broad application value in industrial fields such as pharmaceutical chemicals, food processing, biomaterials, papermaking, and textiles. Nowadays, PEG-400 has been widely used as a solubilizer.

[0005] CN 105401463 A discloses a method for dyeing cotton fibers to a dark color using indigo dye in one step. The method comprises dyeing cotton fibers with indigo dye in a non-aqueous medium system using decamethylcyclopentasiloxane (D5) as a medium to achieve a dark color dyeing effect. However, the indigo dye used is a vat dye, and its structural formula is as follows:

[0006]

[0007] This dye cannot be directly applied to cotton fibers. Instead, it must be reduced to a reduced leuco sodium salt before it can adhere to the cotton fibers through physical and chemical reactions. Sodium hydrosulfite (sodium dithionite) must be added to prevent oxidation of the leuco. After the leuco binds to the fiber, it undergoes an oxidation reaction to reduce it to the original dye and develop color. The addition of PEG is intended to inhibit the oxidation of the reduced leuco and the decomposition of the hydrosulfite, thereby improving the indigo dyeing effect. Some literature also discloses the use of PEG in aqueous systems to improve the dyeing performance of dyes, but in all cases, the fibers are pretreated with PEG before dyeing. Summary of the Invention

[0008] [Technical Issues]

[0009] Currently, there are few studies exploring the lifting power of dyes in non-aqueous dyeing systems.

[0010] PEG is a solubilizer that can be used for fiber pretreatment or to inhibit the oxidation of reduced leuco bodies and the decomposition of hydrosulfur powder. There is no mention of it being used to increase the lifting power of dyes.

[0011] [Technical solution]

[0012] To address the above issues, the present invention improves the dyeing process and provides a method for increasing the dye-lifting power of high-concentration Reactive Black 5 in a non-aqueous medium. This allows higher concentrations of Reactive Black 5 to produce darker fabrics under the same dyeing conditions. Specifically, the present invention optimizes the dyeing process by adding PEG-400 to the dye bath, increasing fabric wettability while also improving the dye-lifting power of Reactive Black 5 in D5. Reactive Black 5 is a reactive dye that can covalently bond with fibers. Furthermore, the PEG-400 used in the present invention improves fiber wettability while reducing reactive dye aggregation, thereby reducing dye hydrolysis and improving dye utilization.

[0013] The first object of the present invention is to provide a method for improving the dyeing lifting power of high-concentration Reactive Black 5 using PEG-400 based on a non-aqueous medium system, comprising the following steps:

[0014] (1) mixing cotton fabric, reactive black 5, water, NaOH, Na2CO3, PEG-400 and D5 to obtain a mixed system;

[0015] (2) The mixed system is kept warm, then heated and kept warm for a period of time, and finally washed and dried to obtain a dyed fabric.

[0016] In one embodiment of the present invention, the cotton fabric is a fabric prepared using cotton fiber as raw material, including cotton knitted fabric, cotton woven fabric, etc.

[0017] In one embodiment of the present invention, the amount of the reactive black 5 in step (1) is 3-5% (owf).

[0018] In one embodiment of the present invention, the amount of water used in step (1) is 120-140% (owf).

[0019] In one embodiment of the present invention, the amount of NaOH used in step (1) is 0.20-0.27% (owf).

[0020] In one embodiment of the present invention, the amount of Na2CO3 used in step (1) is 1.2-2.4% (owf).

[0021] In one embodiment of the present invention, the concentration of PEG-400 in water in step (1) is 2.5-3.5 g / L.

[0022] In one embodiment of the present invention, the amount of D5 in step (1) is calculated based on the bath ratio, which is 15-25:1 (owf).

[0023] In one embodiment of the present invention, the mixing system in step (1) is to first mix cotton fabric, reactive black 5, water, NaOH, and Na2CO3, then add PEG-400, and then add D5 and mix evenly.

[0024] In one embodiment of the present invention, the insulation in step (2) is carried out at 25-35° C. for 25-35 minutes.

[0025] In one embodiment of the present invention, the heating and heat preservation in step (2) is to heat to 75-85°C at a rate of 1.5-2.5°C / min, and the heat preservation is to keep the temperature at 75-85°C for 60-70 minutes.

[0026] In one embodiment of the present invention, the water washing in step (2) is carried out at 90-95° C. for 10-20 min.

[0027] In one embodiment of the present invention, the drying in step (2) is oven drying.

[0028] A second object of the present invention is the dyed fabric prepared by the method according to the present invention.

[0029] In one embodiment of the present invention, the K / S value of the dyed fabric (dye concentration>3%) reaches 21 or above.

[0030] A third object of the present invention is the application of the method of the present invention in cotton fabric dyeing.

[0031] [Beneficial Effects]

[0032] (1) For dyeing dark products, the method of the present invention can improve the dyeing lifting power and utilization rate of the dye and reduce the use of dye.

[0033] (2) Under the same dyeing conditions, when the concentration of PEG-400 is 3 g / L, the K / S value (fabric color yield) of the fabric after dyeing with a higher concentration (>3% (owf)) of Reactive Black 5 in a non-aqueous medium is greater than the K / S value of the fabric dyed without PEG-400. That is, after adding PEG-400, the dyeing lifting power of Reactive Black 5 in a non-aqueous medium is improved. And as the concentration of Reactive Black 5 increases, the lifting effect is more significant. Specifically, when the concentration of Reactive Black 5 is 4% (to the weight of the fabric (owf)), the K / S value of the dyed fabric increases by 11.9% after adding PEG-400; when the concentration of Reactive Black 5 is 5% (owf), the K / S value of the dyed fabric increases by 33.5% after adding PEG-400. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1This is a comparison chart of the K / S values ​​of fabrics dyed with different dye concentrations in Examples 1-3 and the K / S values ​​of fabrics dyed without adding PEG-400 in Comparative Examples 1-3.

[0035] Figure 2 1 is a comparison diagram of the dyed fabric in Example 2 and the dyed fabric in Comparative Example 2 without adding PEG-400.

[0036] Figure 3 3 is a comparison diagram of the dyed fabric in Example 3 and the dyed fabric in Comparative Example 3 without adding PEG-400.

[0037] Figure 4 This is the hydrolysis chromatogram of Reactive Black 5 after adding PEG-400 in Example 3.

[0038] Figure 5 This is the hydrolysis chromatogram of Comparative Example 3 without adding PEG-400 Reactive Black 5.

[0039] Figure 6 for Figure 4 and Figure 5 The chemical structural formulas of the various dye molecules mentioned.

[0040] Figure 7 is the K / S value of the dyed fabric obtained at different dosages of PEG-400 in Example 4. DETAILED DESCRIPTION

[0041] The following describes preferred embodiments of the present invention. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0042] Test method:

[0043] 1. K / S value test: Using a Datacolor 800 spectrophotometer, under light source D65, at an incident angle of 10°, measure three different positions of the sample within the spectral range of 380-700nm. The average K / S value is obtained to evaluate the dyeing lifting power of the dye.

[0044] 2. Capillary Effect Test: Test using a capillary effect tester in accordance with FZ / T 01071-2008, "Test Method for Capillary Effect of Textiles." Cut the specimen into 30 cm x 5 cm sections in both the warp and weft directions. Record the height of water wicking along the fabric within 30 minutes to indicate the wettability of the alkali-treated cotton fiber.

[0045] 3. Color fastness to washing: The color fastness to washing of dyed samples is measured according to GB / T 3921-2008, "Textiles—Tests for Color Fastness—Color Fastness to Washing." The textile sample is sewn together with two pieces of standard adjacent fabric, placed in a soap solution, and mechanically agitated at 95°C for 30 minutes. The sample is then washed and dried. Using the original sample as a reference, discoloration of the sample and staining of the adjacent fabric are assessed using a gray scale or instrument.

[0046] 4. Color fastness to rubbing: The color fastness to rubbing of dyed samples was measured according to GB / T 3920-2008, "Textiles—Tests for Color Fastness—Color Fastness to Rubbing." The test was conducted using a YS71 dye rubbing color fastness tester from Laizhou Yuanmao Instrument Co., Ltd.

[0047] Sources of raw materials used in the examples:

[0048] Cotton fabric: 100% cotton woven plain fabric, weight: 125gsm, specification: 16S / 2-50S / 2, purchased from Shandong Mengyin Cotton Textile Co., Ltd.

[0049] Reactive Black 5: It is a reactive dye (filter cake) purchased from Haining Lvyu Textile Technology Co., Ltd. and has the following structural formula II:

[0050]

[0051] Example 1

[0052] A method for improving the dyeing lifting power of high-concentration Reactive Black 5 using PEG-400 based on a non-aqueous medium system comprises the following steps:

[0053] (1) Cotton cloth, 3% (owf) Reactive Black 5, 130% (owf) water, 0.26% (owf) NaOH, and 1.3% (owf) Na2CO3 were mixed, and then PEG-400 was added to make the concentration of PEG-400 in the aqueous solution be 3 g / L, followed by adding 20 (owf) D5 and mixing uniformly to obtain a mixed system;

[0054] (2) The mixed system was kept at 30°C for 30 min, then heated to 80°C at a rate of 2°C / min, kept at that temperature for 65 min, and finally washed at 95°C for 15 min and dried to obtain the dyed fabric.

[0055] Example 2

[0056] The amount of Reactive Black 5 in step (1) of Example 1 was adjusted to 4% (owf), and the other ingredients were kept consistent with Example 1 to obtain a dyed fabric.

[0057] Example 3

[0058] The amount of Reactive Black 5 in step (1) of Example 1 was adjusted to 5% (owf), and the other ingredients were kept consistent with Example 1 to obtain a dyed fabric.

[0059] Comparative Example 1

[0060] The addition of PEG-400 in step (1) of Example 1 was omitted, and the other steps were kept consistent with Example 1 to obtain a dyed fabric.

[0061] Comparative Example 2

[0062] The addition of PEG-400 in step (1) of Example 2 was omitted, and the other steps were kept consistent with Example 2 to obtain a dyed fabric.

[0063] Comparative Example 3

[0064] The addition of PEG-400 in step (1) of Example 2 was omitted, and the other steps were kept consistent with Example 2 to obtain a dyed fabric.

[0065] The obtained dyed fabric was subjected to performance tests, and the test results are as follows:

[0066] Figure 1 The K / S values ​​of the dyed fabrics of Examples 1-3 with different dye concentrations are compared with the K / S values ​​of the dyed fabrics of Comparative Examples 1-3 without adding PEG-400. Figure 1 It can be seen that when the concentration of Reactive Black 5 is high (>3% (owf)), the addition of PEG-400 can increase the K / S value of the dyed fabric, that is, the dye dyeing lifting power increases, and as the dye concentration increases, the degree of dye dyeing lifting power will further increase. When the concentration of Reactive Black 5 is 4% (owf), after adding 3g / L PEG-400 to the dye liquor, the K / S value of the dyed fabric increased from 19.271 to 21.567. When the concentration of Reactive Black 5 is 5% (owf), after adding 3g / L PEG-400 to the dye liquor, the K / S value of the dyed fabric increased from 20.005 to 26.700, which is mainly related to the capillary effect of the dyed fabric increasing from 9.25cm to 9.47cm.

[0067] Table 1 is a comparison of the color fastness of fabrics with and without PEG-400 added at a Reactive Black 5 concentration of 5%. As can be seen from Table 1, the color fastness of the dyed fabrics is not affected by the addition of PEG-400.

[0068] Table 1 Fastness test results of dyed fabrics obtained in Example 3 and Comparative Example 3

[0069]

[0070] Figure 2: is a comparison diagram of the dyed fabric in Example 2 and the dyed fabric without PEG-400 in Comparative Example 2. Figure 2 It can be seen that the K / S value without adding PEG-400 is 19.271, and after adding PEG-400, the K / S value is 21.567, and the K / S is increased by 11.9%.

[0071] Figure 3 3 is a comparison diagram of the dyed fabric in Example 3 and the dyed fabric without PEG-400 in Comparative Example 3. Figure 3 It can be seen that the K / S value without adding PEG-400 is 20.005, and after adding PEG-400, the K / S value is 26.700, and the K / S value is increased by 33.5%.

[0072] Figure 4 This is the hydrolysis chromatogram of Reactive Black 5 after adding PEG-400 in Example 3; Figure 5 This is the hydrolysis chromatogram of Reactive Black 5 in Comparative Example 3 without adding PEG-400. By comparing the two, it can be seen that: at the same time, the hydrolysis of Reactive Black 5 in the non-aqueous medium is reduced, and the utilization rate of the dye is improved.

[0073] Figure 6 yes Figure 4 and Figure 5 The chemical structural formulas of dyes III, IV, and V mentioned in FIG, wherein dye II is reactive black 5. Figure 6 It can be seen that: as the reactive dye in the dyeing system dyes the cotton fabric, Reactive Black 5 gradually hydrolyzes from dye III with a reactive group (-SO2-CH=CH2) to dye IV with only one reactive group under alkaline conditions and dyeing temperature, and finally both reactive groups are hydrolyzed into non-reactive groups (-SO2-CH2-CH2-OH), and the dye is finally hydrolyzed to dye V. From the structure, it can be seen that the polarity of the hydrolyzed dye gradually increases as the hydrolysis proceeds, which is consistent with the hydrolysis chromatography. Figure 4 and 5 The retention times of the three dyes correspond to each other, that is, the dye V with high polarity elutes first and has the shortest retention time in the chromatographic column.

[0074] Example 4

[0075] The amount of PEG-400 in Example 3 was adjusted to 1.5 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, and 4.0 g / L, and the other contents were kept the same as in Example 1 to obtain dyed fabrics.

[0076] The obtained dyed fabric was subjected to performance test, and the test results were as follows. Figure 7 shown.

[0077] from Figure 7As can be seen, as the PEG-400 concentration increases from 0 to 3.0 g / L, the K / S value of the dyed fabric gradually increases from 20.005 to 26.700, reaching a maximum. When the PEG-400 concentration exceeds 3.0 g / L, the K / S value of the dyed fabric gradually decreases. Therefore, the PEG-400 dosage is selected to be 3.0 g / L.

[0078] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for improving the dyeing lifting power of high-concentration Reactive Black 5 using PEG-400 based on a non-aqueous medium system, characterized in that: The steps include: (1) Cotton fabric, Reactive Black 5, water, NaOH, Na2CO3, PEG-400 and D5 are uniformly mixed to obtain a mixed system; the amount of Reactive Black 5 is 5% (owf); the concentration of PEG-400 in water is 2.5-3.5 g / L; the amount of water is 120-140% (owf); the amount of D5 is calculated according to the bath ratio, and the bath ratio is 15-25:1 (owf); (2) The mixed system is kept warm, then heated and kept warm for a period of time, and finally washed and dried to obtain the dyed fabric.

2. The method according to claim 1, characterized in that In step (1), the mixing system is to first mix cotton fabric, reactive black 5, water, NaOH, and Na2CO3, then add PEG-400, and then add D5 and mix evenly.

3. The method according to claim 1, characterized in that In step (2), the mixed system is kept warm at 25-35° C. for 25-35 minutes.

4. The method according to claim 1, wherein In step (2), the temperature is raised to 75-85°C at a rate of 1.5-2.5°C / min, and the temperature is kept at 75-85°C for 60-70 minutes.

5. The dyed fabric prepared by the method according to any one of claims 1 to 4.

6. Application of the method according to any one of claims 1 to 4 in cotton fabric dyeing.

Images