Wool vat dye dyeing process based on high-alkalinity low-temperature dyeing

Abstract

The invention belongs to the technical field of textile printing and dyeing, and relates to a wool vat dye dyeing process based on high-alkalinity low-temperature dyeing. The technology comprises the following steps: dissolving vat dye, a penetrant, Na2SO4 and sodium hydrosulfite in water, adjusting the pH value, and carrying out a reduction reaction to obtain dye liquor; immersing the wool textile into the dye liquor for dyeing, and maintaining the pH during dyeing; washing the wool textile with water, then adjusting the pH value of the H2O2 aqueous solution, and immersing the wool textile for oxidation treatment; sodium hydrosulfite and NaOH are dissolved in water to obtain a cleaning solution, and the wool textile is immersed in the cleaning solution for reduction cleaning treatment. Wool disulfide bond breakage and fiber swelling are promoted under the alkaline condition, dye is fully permeated at the low temperature, dyeing uniformity is ensured, color fastness is improved, the dye utilization rate is increased, the color vividness, saturation and stability are improved, the light fastness reaches the level 4-5, and wool medium-color and dark-color dyeing of the vat dye is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of textile printing and dyeing, and relates to a wool vat dyeing process based on high alkalinity and low temperature dyeing. Background Art

[0002] Traditional wool dyeing mostly uses reactive dyes or acid dyeing processes under acidic conditions, which has the problem of insufficient light fastness: the light fastness of conventional reactive dyes for wool is generally 2 to 3 levels (ISO 105-B02 standard), which is difficult to meet the needs of high-end textiles.

[0003] In the prior art, vat dyes are mostly used for dyeing cellulose fibers and are generally not used for dyeing wool. Vat dyes need to be reduced to leuco forms under alkaline conditions before they can dye fibers, and wool is easily damaged under strong alkaline conditions. The leuco forms of vat dyes are relatively large, and the dense structure of wool fibers makes it difficult for dye molecules to diffuse into the wool fibers, resulting in a low dyeing rate and difficulty in obtaining a dark color effect. These problems have limited the application of vat dyes on wool. Although some studies have attempted to improve permeability through alkaline conditions, the problem of synergistically improving the dyeing rate and color fastness of low-temperature dyeing has not been solved. Summary of the Invention

[0004]

Technical Issues

[0005] Wool dyed with reactive dyes or acid dyes has insufficient light fastness, and wool dyed with vat dyes has low dye uptake. A wool dyeing method with high color fastness and high dye uptake is needed.

[0006]

Technical solution

[0007] To address these issues, the present invention utilizes low-temperature, high-alkali conditions to synergistically enhance the color uptake and color fastness of vat dyed wool. Alkaline conditions (pH ≥ 11.5) cleave the disulfide bonds in the wool and simultaneously swell the fiber, achieving full dye penetration at low temperatures (nearly 40°C). The resulting wool textiles achieve a light fastness of 4-5, over two levels higher than traditional reactive dyeing.

[0008] The first object of the present invention is to provide a wool dyeing process based on high alkalinity and low temperature, comprising the steps of:

[0009] S1. Dye solution preparation: dissolve vat dye, penetrant, Na2SO4, and hydrosulfite in water, adjust the pH to carry out reduction reaction, and obtain dye solution;

[0010] S2, low temperature dyeing: immerse the wool textile in the dye solution and dye while maintaining the pH;

[0011] S3, oxidation fixation: washing the wool textile treated in step S2, and then immersing it in a H2O2 aqueous solution for oxidation treatment;

[0012] S4. Reduction cleaning: immersing the wool textile treated in S3 in a cleaning solution for reduction cleaning to obtain a dyed wool textile; the cleaning solution is prepared by dissolving hydrosulfite and NaOH in water.

[0013] In one embodiment of the present invention, in step S1, the vat dye is selected from anthraquinone and indigo vat dyes.

[0014] In one embodiment of the present invention, in step S1, the amount of vat dye in the dye solution is 0.01-2% owf (to the weight of the fabric); the penetrant concentration is 0.5-2 g / L; the Na2SO4 concentration is 10-50 g / L; and the hydrosulfite concentration is 2-10 wt%.

[0015] In one embodiment of the present invention, in step S1, the reduction reaction is carried out at 35-45° C. for 20-40 minutes.

[0016] In one embodiment of the present invention, in step S1, the pH is adjusted to 11.5-12.5; NaOH is used to adjust the pH.

[0017] In one embodiment of the present invention, in step S2, the wool textile is a wool textile that has been mercerized and / or subjected to a subtractive shrinkage treatment.

[0018] Wool has a lot of scales on its surface, so the color depth is very shallow at low temperatures. However, mercerized wool or subtractive shrink-proof wool has some of its scales removed, so low-temperature dyeing can achieve a better depth.

[0019] In one embodiment of the present invention, in step S2, the dyeing temperature is 35-45°C, the dyeing time is 30-60 min; the dyeing bath ratio (mass ratio of wool to treatment liquid) is 1:(8-12); the pH is maintained at 11.5-12.5 by adding an alkaline regulator, and the pH fluctuation is ≤±0.3; the alkaline regulator is selected from one of NaOH, KOH, Na2CO3, and Na3PO4.

[0020] For every 0.5 decrease in the pH of the dye liquor, the dyeing depth (K / S value) can decrease by 15% to 20%. The present invention controls the dyeing rate and dyeing depth by precisely adjusting the pH (±0.3 accuracy), achieving fine-tuning of color depth, ensuring dyeing uniformity, improving color fastness, and increasing dye utilization. Alkaline conditions (pH ≥ 12) promote the rupture of wool disulfide bonds and fiber swelling, achieving full dye penetration at low temperatures (40°C), avoiding color spots and color flowers, enhancing color fastness, and improving color vividness, saturation, and stability.

[0021] In one embodiment of the present invention, in step S3, the number of water washings is 1 to 2 times.

[0022] In one embodiment of the present invention, in step S3, the H2O2 concentration of the H2O2 aqueous solution is 0.1-0.2 wt%.

[0023] In one embodiment of the present invention, in step S3, the pH of the H2O2 aqueous solution is adjusted to 5-6; the pH is adjusted with acetic acid.

[0024] In one embodiment of the present invention, in step S3, the temperature of the oxidation treatment is 35-45° C., the time of the oxidation treatment is 6-20 min, and the bath ratio of the oxidation treatment is 1:(8-12).

[0025] In one embodiment of the present invention, in step S4, the concentration of hydrosulfite in the cleaning solution is 1-3 g / L; the concentration of NaOH in the cleaning solution is 1-2 g / L.

[0026] In one embodiment of the present invention, in step S4, the temperature of the reduction cleaning is 45-50° C., the time of the reduction cleaning is 6-15 minutes, and the bath ratio of the reduction cleaning is 1:(8-12).

[0027] In one embodiment of the present invention, in step S4, the temperature of the reduction cleaning is preferably 50° C., and the time of the reduction cleaning is preferably 15 minutes.

[0028] The optimized hydrosulfite concentration and reduction cleaning treatment temperature and time are beneficial to removing floating colors, improving color fastness, reducing wool fiber damage and lowering energy consumption.

[0029] The solution of the present invention has a wide tolerance for raw materials, and conventional commercially available wool that has been mercerized and / or subjected to subtractive shrinkage treatment can be well applied in the present invention.

[0030] In one embodiment of the present invention, the mercerization treatment is selected from one or more of plasma mercerization treatment, ultraviolet mercerization treatment, chlorination mercerization treatment, oxidation mercerization treatment, and enzyme mercerization treatment.

[0031] In one embodiment of the present invention, the subtractive shrinkage-proofing treatment is selected from one or more of chlorination shrinkage-proofing treatment, enzyme shrinkage-proofing treatment, oxidation shrinkage-proofing treatment, ultrasonic shrinkage-proofing treatment, and plasma shrinkage-proofing treatment.

[0032] A second object of the present invention is to provide dyed wool textiles produced by the wool dyeing process.

[0033] The third object of the present invention is to provide application of the dyed wool textile in the field of textiles.

[0034] Beneficial effects:

[0035] This invention utilizes low temperature and high alkali conditions to synergistically enhance the color uptake and color fastness of wool dyed with vat dyes. Alkaline conditions (pH ≥ 11.5) promote the rupture of disulfide bonds in the wool and simultaneous fiber swelling, enabling full dye penetration at low temperatures (nearly 40°C). This ensures dyeing uniformity, improves color fastness, enhances dye utilization, and enhances color vividness, saturation, and stability. The dyed wool textiles achieve a light fastness of 4 to 5, enabling the dyeing of medium and dark colors with vat dyes. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the process of high alkalinity and low temperature dyeing in Example 3.

[0037] Figure 2 The light fastness test results of Example 2 and Comparative Example 1 are shown. DETAILED DESCRIPTION

[0038] Example 1

[0039] A wool dark dyeing process based on high alkalinity and low temperature comprises the following steps:

[0040] S1. Dye solution preparation: dissolve vat dye (GM black, Yabang dye), penetrant, Na2SO4, and hydrosulfite in water, adjust the pH to 12.5 with NaOH, reduce at 40℃ for 30min, and then add water to obtain dye solution;

[0041] The dosage of vat dye is 1% owf; the concentration of penetrant in the dye solution is 1.0 g / L, the concentration of Na2SO4 is 20 g / L, and the concentration of hydrosulfite is 8 wt%;

[0042] S2. Low-temperature dyeing: Immerse mercerized wool textiles in dye liquor with a bath ratio of 1:10 and dye at 40°C for 45 minutes. During this period, add an alkaline regulator to maintain the pH so that the pH fluctuation is ≤±0.3.

[0043] S3, oxidative color fixation: the wool textile treated in step S2 was washed twice, and a H2O2 aqueous solution with a H2O2 concentration of 0.15 wt% was prepared with a 30% H2O2 solution, and the pH of the H2O2 aqueous solution was adjusted to 5-6 with acetic acid, and the wool textile was immersed in the aqueous solution, with a bath ratio of 1:10, and oxidized at 40°C for 20 min;

[0044] S4. Reduction cleaning: dissolve hydrosulfite and NaOH in water to obtain a cleaning solution with a Na2S2O4 concentration of 2g / L and a NaOH concentration of 2g / L. Immerse wool textiles with a bath ratio of 1:10 and perform reduction cleaning at 50°C for 15 minutes.

[0045] Example 2

[0046] A medium-light wool dyeing process based on high alkalinity and low temperature is different from Example 1 only in that, in step S1, the amount of vat dye used is 0.5% owf, and NaOH is used to adjust the pH to 11.8.

[0047] Example 3

[0048] A wool dyeing process based on high alkalinity and low temperature is different from Example 1 in that, in step S2, the dyeing time of 45 minutes is replaced by 60 minutes.

[0049] Figure 1 Schematic diagram of the wool dyeing process of Example 3.

[0050] Example 4

[0051] A wool dyeing process based on high alkalinity and low temperature, comprising the steps of:

[0052] S1. Dye solution preparation: dissolve vat dye (GM black, Yabang dye), penetrant, Na2SO4, and hydrosulfite in water, adjust the pH to 11.5 with NaOH, reduce at 45°C for 20 minutes, and then add water to obtain the dye solution;

[0053] The dosage of vat dye is 0.05% owf; the concentration of penetrant in the dye solution is 0.5g / L, the concentration of Na2SO4 is 10g / L, and the concentration of hydrosulfite is 6wt%;

[0054] S2. Low-temperature dyeing: Immerse mercerized wool textiles in dye liquor with a bath ratio of 1:12 and dye at 35°C for 55 minutes. During this period, add an alkaline regulator to maintain the pH so that the pH fluctuation is ≤±0.3.

[0055] S3, oxidative color fixation: the wool textile treated in step S2 was washed twice, and a H2O2 aqueous solution with a H2O2 concentration of 0.1 wt% was prepared with a 30% H2O2 solution, and the pH of the H2O2 aqueous solution was adjusted to 5-6 with acetic acid, and the wool textile was immersed in the aqueous solution, with a bath ratio of 1:12, and oxidized at 35°C for 10 min;

[0056] S4. Reduction cleaning: dissolve hydrosulfite and NaOH in water to obtain a cleaning solution with a Na2S2O4 concentration of 1g / L and a NaOH concentration of 1g / L. Immerse wool textiles with a bath ratio of 1:12 and perform reduction cleaning at 45°C for 8 minutes.

[0057] Example 5

[0058] A wool dyeing process based on high alkalinity and low temperature, comprising the steps of:

[0059] S1. Dye solution preparation: dissolve vat dye (GM black, Yabang dye), penetrant, Na2SO4, and hydrosulfite in water, adjust the pH to 12 with NaOH, reduce at 45℃ for 35min, and then add water to obtain dye solution;

[0060] The dosage of vat dye is 2% owf; the concentration of penetrant in the dye solution is 1.8g / L, the concentration of Na2SO4 is 35g / L, and the concentration of hydrosulfite is 10wt%;

[0061] S2. Low-temperature dyeing: Immerse mercerized wool textiles in dye liquor with a bath ratio of 1:11 and dye at 45°C for 55 minutes. During this period, add an alkaline regulator to maintain the pH so that the pH fluctuation is ≤±0.3.

[0062] S3, oxidative color fixation: the wool textile treated in step S2 was washed twice, and a H2O2 aqueous solution with a H2O2 concentration of 0.20 wt% was prepared with a 30% H2O2 solution, and the pH of the H2O2 aqueous solution was adjusted to 5-6 with acetic acid, and the wool textile was immersed in the aqueous solution, with a bath ratio of 1:12, and oxidized at 40°C for 20 min;

[0063] S4. Reduction cleaning: dissolve hydrosulfite and NaOH in water to obtain a cleaning solution with a Na2S2O4 concentration of 3g / L and a NaOH concentration of 1g / L. Immerse wool textiles with a bath ratio of 1:12 and perform reduction cleaning at 48°C for 12 minutes.

[0064] Comparative Example 1

[0065] Traditional wool dyeing process with reactive dyes (pH 4.5, 98°C, 40 min).

[0066] According to the American standard (AATCC 16.3-2014), the light fastness of Example 1 was tested for 168 hours, the light fastness of Example 1 was level 5, the light fastness of Example 2 was level 4, and the light fastness of Comparative Example 1 was only level 1.5. Figure 2 The light fastness test results of Example 2 and Comparative Example 1 are shown. Figure 2 The fabric sample in the middle and upper part is the comparative example 1 which has been tested for sunlight fastness. It can be seen that the color of the unshielded area is significantly lighter than that of the shielded area during the simulated sunlight test. Figure 2 The following fabric sample is from Example 2, which was tested for light fastness. It can be seen that the color difference between the unshaded and shaded areas is not much. This demonstrates that the low-temperature dyeing process of the present invention exhibits excellent light fastness to wool textiles and can produce dark, uniformly colored wool textiles.

[0067] The embodiments provided above are not intended to limit the scope of the present invention, nor are the steps described to limit their execution order. Any obvious improvements to the present invention made by those skilled in the art in combination with existing common knowledge shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A wool dyeing process based on high alkalinity and low temperature, characterized in that: Including steps: S1. Dye solution preparation: dissolve vat dye, penetrant, Na2SO4, and hydrosulfite in water, adjust the pH to carry out reduction reaction, and obtain dye solution; S2, low temperature dyeing: immerse the wool textile in the dye solution and dye while maintaining the pH; S3, oxidation fixation: washing the wool textile treated in step S2, and then immersing it in a H2O2 aqueous solution for oxidation treatment; S4, reduction cleaning: immersing the wool textile treated in step S3 in a cleaning solution for reduction cleaning to obtain a dyed wool textile; the cleaning solution is prepared by dissolving hydrosulfite and NaOH in water.

2. The wool dyeing process according to claim 1, characterized in that: In step S1, the vat dye is selected from anthraquinone and indigo vat dyes; the amount of vat dye in the dye solution is 0.01-2% owf; the penetrant concentration is 0.5-2 g / L; the Na2SO4 concentration is 10-50 g / L; and the hydrosulfite concentration is 2-10 wt%.

3. The wool dyeing process according to claim 1, characterized in that: In step S1, the reduction reaction conditions are: treatment at 35-45° C. for 20-40 min; adjusting the pH to 11.5-12.5; and adjusting the pH with NaOH.

4. The wool dyeing process according to claim 1, characterized in that: In step S2, the dyeing temperature is 35-45° C., the dyeing time is 30-60 min, the dyeing bath ratio is 1:(8-12), the pH is maintained at 11.5-12.5 by adding an alkaline regulator, and the pH fluctuation is ≤±0.3; the alkaline regulator is selected from one of NaOH, KOH, Na2CO3, and Na3PO4.

5. The wool dyeing process according to claim 1, characterized in that: In step S3, the number of water washings is 1 to 2 times; the H2O2 concentration of the H2O2 aqueous solution is 0.1 to 0.2 wt%; the pH of the H2O2 aqueous solution is adjusted to 5 to 6; and acetic acid is used to adjust the pH.

6. The wool dyeing process according to claim 1, characterized in that: In step S3, the temperature of the oxidation treatment is 35-45° C., the time of the oxidation treatment is 6-20 min, and the bath ratio of the oxidation treatment is 1:(8-12).

7. The wool dyeing process according to claim 1, characterized in that: In step S4, the concentration of hydrosulfite in the cleaning solution is 1-3 g / L; the concentration of NaOH in the cleaning solution is 1-2 g / L.

8. The wool dyeing process according to claim 1, characterized in that: In step S4, the temperature of reduction cleaning is 45-50° C., the time of reduction cleaning is 6-15 minutes, and the bath ratio of reduction cleaning is 1:(8-12).

9. Dyed wool textiles produced by the wool dyeing process according to any one of claims 1 to 8.

10. Use of the dyed wool textile according to claim 9 in the field of textiles.

Images