Yellow reductive staining agent, staining solution as well as preparation method and application of yellow reductive staining agent and staining solution

Abstract

The invention discloses a yellow reduction dyeing agent, a dyeing solution and a preparation method and application thereof, and relates to the technical field of dyeing and finishing. According to the yellow reduction dyeing agent provided by the invention, the 5-hydroxy-3-aminopyridine-2, 6-(1H, 3H)-diketone is adopted as a reduction dye, and the sodium sulfite is independently used as a reducing agent for reduction dyeing, so that the obtained dye leuco body is proper in dyeing capacity, and a dyed fabric can show excellent light brittle damage resistance. The fabric dyed by the dyeing agent has similar breaking strength before and after dyeing and even is slightly improved after dyeing and illumination, meanwhile, the color depth K / S of the fabric dyed by the dyeing agent reaches 3.2 or above, the dry and wet rubbing color fastness can reach level 4 or above, and the color fastness to illumination reaches level 6 or above.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dyeing and finishing, in particular to a yellow vat dye, a dyeing solution and a preparation method and application thereof. BACKGROUND

[0002] Yellow as one of the three primary colors of pigments has a large number of application scenarios in reality. Natural yellow dyes include plant dyes such as artemisia japonica, gardenia, sophora flower, turmeric and phoebe zhennan, but natural yellow dyes have the disadvantages of poor stability, slow dyeing rate and poor batch stability. With the progress of the dyeing and finishing field, natural dyes have been replaced by artificially prepared organic and inorganic yellow dyes, but existing inorganic yellow dyes are mostly heavy metal dyes, which are harmful to the human body and the environment, and organic yellow dyes have poor light fastness and other properties. Specifically, existing organic yellow dyes include isoindolinone yellow, vat yellow and fast yellow G, which usually present yellow due to the presence of color groups containing azo structures, aromatic ring structures or conjugated systems, but these structural fragments can easily produce active substances under light, causing oxidative degradation of fabric fibers, and thus leading to a decrease in the strength of the fibers, resulting in light brittle damage to the fibers and fabrics after dyeing, which is a typical problem of organic yellow dyes. In order to solve this problem, it is urgent to provide a new yellow dyeing agent. SUMMARY

[0003] In order to solve the problems of the prior art, the present application provides a yellow vat dyeing agent, which uses 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione as a vat dye and sodium sulfite as a reducing agent for vat dyeing, and the resulting dyed fabric can exhibit excellent light brittle resistance.

[0004] Another object of the present application is to provide a yellow vat dyeing solution.

[0005] Another object of the present application is to provide a preparation method of a yellow vat dyeing solution.

[0006] Another object of the present application is to provide a dyeing method.

[0007] The above objects of the present application are achieved by the following technical solutions:

[0008] A yellow vat dyeing agent, comprising 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione and a reducing agent, wherein the reducing agent is sodium sulfite, and the mass ratio of the reducing agent to 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione is greater than or equal to 0.2:1.

[0009] 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione, as a pyridone compound, is identified as a vat dye by ISO 16373-1:2015 (General principles of testing coloured textiles for dyestuff identification), so when using this compound for dyeing, a reducing agent needs to be added to reduce it into a water-soluble leuco body first, which can be adsorbed by fibers, and then oxidized by air to develop color, and the leuco body is converted into an insoluble pigment to be dyed on the fibers.

[0010] Sodium sulfite, as a common reducing agent, cannot be used alone for the reduction dyeing of other vat dyes due to its weak reducing ability. However, the inventors of the present application found through a large number of experimental studies that sodium sulfite can not only be used alone as a reducing agent for 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione, but also only when sodium sulfite, a weak reducing agent, is used alone for reduction dyeing, the obtained leuco body has suitable dyeing ability, which can weaken the damage to the fibers while ensuring the dyeing performance, thus improving the light brittle resistance of the fabric fibers after dyeing. If a strong reducing agent such as sodium hydrosulfite is used for reduction, the reduction of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione is significantly greater than oxidation, the fabric color will be lighter, and under the condition of higher oxidation-reduction potential, it is more difficult to maintain the stability of the potential of the strong reducing agent such as sodium hydrosulfite.

[0011] It should be noted that too low an amount of sodium sulfite will result in insufficient reduction of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione, and good dyeing effect cannot be obtained.

[0012] In the specific embodiment of the present application, the preparation method of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione is carried out according to the preparation method in Chinese patent CN202510378948.9.

[0013] In the specific embodiment of the present application, the type of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione identified by ISO 16373-1:2015 (General principles of testing coloured textiles for dyestuff identification) includes the following steps:

[0014] A. 0.2g of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione sample was put into boiling 10 mL 1% ammonia solution for 1 minute, after centrifugation at 13000 r / min for 5 min, there was no color in the solution, and yellow precipitate was generated at the bottom of the test tube, indicating that the sample was not dissolved in 1% ammonia water, and therefore it was not an acid dye;

[0015] B. 0.2g of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione sample was put into boiling 5% acetic acid for 1 min, and the color of the solution did not change significantly, and after centrifugation, a large amount of yellow precipitate was generated, and the supernatant did not change significantly in color, indicating that 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione was not a basic dye;

[0016] C. 0.2g of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione sample was directly added to 5% sodium hydroxide solution, and then centrifuged at 13000 r / min for 5 min. Because the imine of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione will be destroyed and lose color at pH>11, the supernatant is clear and colorless, but there is still precipitate at the bottom, which shows that the sample is basically insoluble in 5% sodium hydroxide, indicating that 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione is neither a direct dye nor a reactive dye;

[0017] D. 0.2g of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione sample was dispersed in a pH 10 aqueous solution, then water and sodium hydrosulfite were added, the test tube was shaken, the solution color changed to light yellow and transparent, then oxidized to turbid yellow, and then cold diluted sodium hypochlorite solution was continuously added, the solution color did not change, indicating that 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione was a reducing dye;

[0018] E. 0.2g of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione was treated with 16% hydrochloric acid, heated and cooled, and then a magnesium strip was added. The color of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione changed in 16% hydrochloric acid, but after testing with lead acetate paper, it did not turn black, and no hydrogen sulfide odor gas was generated, indicating that 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione was not a sulfur dye.

[0019] In summary, after identification, 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione belongs to a reducing dye.

[0020] Preferably, the yellow reducing dyeing agent comprises the following components by mass fraction:

[0021] 0.2-3 parts of reducing agent, 1 part of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione.

[0022] If the amount of sodium sulfite is too high, the dye wastewater formed after the dyeing solution completes dyeing has too high COD, and the treatment pressure is high and not environmentally friendly.

[0023] More preferably, the mass fraction of the reducing agent in the yellow vat dyeing agent is 0.5-3 parts.

[0024] The application also protects a yellow vat dyeing solution, which comprises the yellow vat dyeing agent and a solvent.

[0025] Preferably, the solvent comprises water.

[0026] More preferably, the yellow vat dyeing solution comprises the following components in terms of mass fraction:

[0027] 1 part of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione, 0.2-3 parts of reducing agent, 0.1-1 part of alkali agent, and 100-500 parts of water.

[0028] The addition of the alkali agent can stabilize the pH of the yellow vat dyeing solution at weakly acidic, neutral to weakly alkaline (pH 6.0-9.0). In the specific embodiments of the application, the alkali agent comprises at least one of ammonia, sodium carbonate, and sodium bicarbonate.

[0029] Sodium hydroxide, i.e., caustic soda, is conventionally used to adjust the pH of the dyeing solution. However, sodium hydroxide is too alkaline, and the addition of a small amount of sodium hydroxide can cause the pH of the dyeing solution to reach strong alkalinity (pH 11.0-13.0), which can damage the pigment and is not suitable for the dyeing of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione in the application.

[0030] It should be noted that by controlling the ratio of the components, the mass-volume ratio of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione to the solvent in the yellow vat dyeing agent can be controlled to be (2-10) g:1 L (1 part of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione is added to 100 parts of solvent water, and the concentration is 10 g / L).

[0031] More preferably, the alkali agent comprises sodium carbonate.

[0032] More preferably, the yellow vat dyeing solution only comprises the following components in terms of mass fraction:

[0033] 1 part of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione, 0.2-3 parts of reducing agent, 0.1-1 part of sodium carbonate, and 100-500 parts of solvent.

[0034] More preferably, the yellow vat dyeing solution only comprises the following components in mass fraction:

[0035] 1 part of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione, 0.5-2 parts of reducing agent, 0.2-0.5 parts of sodium carbonate, 200-300 parts of solvent.

[0036] The application also protects a preparation method of the above yellow vat dyeing solution, comprising the following steps:

[0037] Mixing the components, and then mashing for 10-90 min at 10-80℃ to obtain the yellow vat dyeing solution.

[0038] Controlling the temperature and time during mashing can ensure that 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione in the yellow vat dyeing solution is fully reduced.

[0039] In the specific embodiment of the application, the mixing of the components is as follows: first dispersing 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione in water, and then sequentially adding sodium sulfite and sodium carbonate and mixing.

[0040] Preferably, the temperature during mashing is 25-60℃, and the time during mashing is 10-30 min.

[0041] The application also protects a dyeing method, which uses the yellow vat dyeing solution to dye a fabric, and the fabric comprises at least one of hydrophilic fabric and hydrophobic fabric.

[0042] Preferably, the hydrophilic fabric comprises at least one of cotton fabric, linen fabric, silk fabric, wool fabric, and cellulose fiber fabric.

[0043] Preferably, the hydrophobic fabric comprises at least one of leather fabric, polyester fabric, and nylon fabric.

[0044] Preferably, the temperature during dyeing is 10-80℃.

[0045] Preferably, the temperature during dyeing is 25-60℃.

[0046] Preferably, the dyeing comprises sequentially performing dip dyeing and oxidation, the bath ratio of the dip dyeing is (100-200):1, the time is 0.5-30 min, and the time of the oxidation is 1-10 min.

[0047] In the specific embodiment of the application, the oxidation comprises exposing the fabric to air.

[0048] Preferably, the dyeing is performed for 1-15 passes.

[0049] In the detailed description of the present application, the dyeing pass refers to the number of repetitions of dyeing, i.e. the number of times of repeated dip dyeing and oxidation. The color depth is different according to the number of dyeing passes, and the dyeing depth gradually increases with the increase of the number of dyeing passes.

[0050] More preferably, the dyeing pass is 1-10 passes.

[0051] Preferably, the dyeing further comprises a washing step.

[0052] More preferably, the bath ratio of the washing is ≥100:1.

[0053] In the detailed description of the present application, the bath ratio is the ratio of the volume of yellow reduction dyeing liquid to the weight of fabric, and the bath ratio is 100:1, which means that 100 liters of dyeing liquid are needed for every 1 kilogram of fabric.

[0054] The bath ratio of the washing liquid to the fabric is at least 100:1, so as to ensure sufficient washing of the dyed fabric and removal of surface impurities and floating color.

[0055] More preferably, the temperature of the washing is 30-60°C.

[0056] With the increase of temperature, the washing effect of the soap solution is stronger, and if the temperature exceeds 60°C, the molecular structure of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione may be destroyed.

[0057] More preferably, the time of the washing is 5-20 minutes.

[0058] If the time of the washing is less than 5 minutes, the impurities and floating color on the fabric surface are not removed sufficiently, and if the time is more than 20 minutes, the washing effect of the soap solution no longer changes.

[0059] More preferably, the washing liquid used in the washing is a soap solution, and the concentration of the soap solution is 1-10 g / L. In the detailed description of the present application, the soap solution is a solution prepared by dissolving soap meeting the GB / T 3921-2008 standard in water.

[0060] If the concentration of the soap solution is less than 1 g / L, the impurities and floating color on the fabric surface are not removed sufficiently, and if the concentration is more than 10 g / L, the washing effect of the soap solution no longer changes, resulting in the waste of soap pieces.

[0061] More preferably, the washing further comprises a drying step.

[0062] Compared with the prior art, the present application has the following beneficial effects:

[0063] The breaking strength of the fabric before and after dyeing is similar, and even slightly improved after dyeing and light exposure, indicating that the yellow reducing dyeing agent in the application can avoid causing fabric light brittle damage phenomenon. At the same time, the fabric dyed by the application has a color depth K / S of 3.2 or more, dry and wet rubbing fastness of 4 or more, and light fastness of 6 or more. BRIEF DESCRIPTION OF DRAWINGS

[0064] Figure 1 The chemical structural formula of 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione used in the application is shown in the figure.

[0065] Figure 2 The corresponding experimental results for identifying 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione as a type of dye using ISO 16373-1:2015 (General principles of testing coloured textiles for dyestuff identification) are shown in the figure.

[0066] Figure 3 The comparison chart of dyeing effect of cotton fabric using the dyeing liquid provided by the application examples 1-3 is shown in the figure.

[0067] Figure 4 The comparison chart of dyeing effect of cotton fabric in the effect examples 6-9 of the application is shown in the figure.

[0068] Figure 5 The comparison chart of dyeing effect of cotton fabric using the dyeing liquid provided by the application comparative examples 1-2 is shown in the figure.

[0069] Figure 6 The comparison chart of dyeing effect of different fiber fabrics using the dyeing liquid provided by the application comparative examples 5 and effect examples 10-19 is shown in the figure. DETAILED DESCRIPTION

[0070] The application will be further described in conjunction with specific embodiments, but the embodiments do not limit the application in any form. Unless otherwise specified, the raw materials used in the embodiments of the application are conventional commercially available raw materials. Among them, the raw material information used in each embodiment and comparative example is as follows:

[0071] 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione: prepared according to the preparation method in Chinese patent CN202510378948.9.

[0072] Reducing yellow G: commercially available, CAS number: 475-71-8.

[0073] Cellulose fiber fabric: commercially available, Lyocell fiber (regenerated cellulose fiber) fabric.

[0074] Examples 1-7

[0075] The present example provides a series of yellow vat dyeing liquids with different component proportions and pH values, including the following components in mass parts:

[0076] 1 part 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione, 0.2-3 parts reducing agent, 0.1-1 parts sodium carbonate, 100-500 parts solvent, the reducing agent being sodium sulfite, and the solvent being water.

[0077] The preparation method of the yellow vat dyeing liquid provided in the present example includes the following steps:

[0078] Mix 5-hydroxy-3-amino pyridine-2,6-(1H,3H)-dione with solvent, and sequentially add reducing agent and sodium carbonate, and then heat at 45°C for 30 min to obtain the product.

[0079] In the present example, the mass parts of each component in the yellow vat dyeing liquid are as shown in Table 1 below:

[0080] Table 1. Mass parts of each component in the yellow vat dyeing liquid in Examples 1-7

[0081]

[0082]

[0083] Example 8

[0084] A yellow vat dyeing liquid, which differs from Example 6 only in that:

[0085] Sodium carbonate is replaced by an equal mass of sodium hydroxide.

[0086] The preparation method of the yellow vat dyeing liquid in the present example is consistent with that of Example 6.

[0087] Example 9

[0088] A yellow vat dyeing liquid, which differs from Example 6 only in that:

[0089] In the preparation method of the yellow vat dyeing liquid in the present example, the reducing agent and sodium carbonate are added and then heated at 35°C for 90 min.

[0090] Example 10

[0091] A yellow vat dyeing liquid, which differs from Example 6 only in that:

[0092] In the preparation method of the yellow reducing staining solution in this embodiment, after adding reducing agent and sodium carbonate, the solution is dissolved at 80°C for 10 minutes.

[0093] Comparative Example 1

[0094] A yellow reducing staining solution, which differs from Example 6 only in that:

[0095] Replace sodium sulfite with an equal mass of sodium dithionite.

[0096] The preparation method of the yellow reducing staining solution in this comparative example is consistent with that in Example 6.

[0097] Comparative Example 2

[0098] A yellow reducing staining solution, which differs from Example 6 only in that:

[0099] Replace sodium sulfite with an equal mass of thiourea dioxide.

[0100] The preparation method of the yellow reducing staining solution in this comparative example is consistent with that in Example 6.

[0101] Comparative Example 3

[0102] A yellow reducing staining solution, which differs from Example 6 only in that:

[0103] The reducing agent consists of 0.5 parts sodium sulfite and 0.5 parts sodium dithionite.

[0104] The preparation method of the yellow reducing staining solution in this comparative example is consistent with that in Example 6.

[0105] Comparative Example 4

[0106] A yellow reducing staining solution, which differs from Example 6 only in that:

[0107] The reducing agent consists of 0.5 parts sodium sulfite and 0.5 parts thiourea dioxide.

[0108] The preparation method of the yellow reducing staining solution in this comparative example is consistent with that in Example 6.

[0109] Comparative Example 5

[0110] A yellow reducing staining solution, comprising the following components in parts by weight:

[0111] 1 part Reducing Yellow G, 3 parts Reducing Agent, 0.8 parts Sodium Hydroxide, 200 parts Solvent, wherein the reducing agent is sodium dithionite and the solvent is water.

[0112] The method for preparing the yellow reducing staining solution provided in this comparative example includes the following steps:

[0113] Mix Reduced Yellow G with a solvent, then add a reducing agent and sodium hydroxide in sequence, and thaw at 80°C for 30 minutes to obtain the final product.

[0114] Comparative Example 6

[0115] A yellow reducing staining solution, which differs from Example 6 only in that:

[0116] Replace 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione with an equal mass of reduced yellow G.

[0117] The preparation method of the yellow reducing staining solution in this comparative example is consistent with that in Example 6.

[0118] Comparative Example 7

[0119] A yellow reducing staining solution, which differs from Example 6 only in that:

[0120] The reducing agent is 1 part sodium sulfite and 0.5 parts thiourea dioxide.

[0121] The preparation method of the yellow reducing staining solution in this comparative example is consistent with that in Example 6.

[0122] Comparative Example 8

[0123] A yellow reducing staining solution, which differs from Example 6 only in that:

[0124] The mass fraction of sodium sulfite is 0.1 parts.

[0125] The preparation method of the yellow reducing staining solution in this comparative example is consistent with that in Example 6.

[0126] Performance testing

[0127] I. Dyeing Effect Test

[0128] First, the yellow reducing dyeing solution obtained in the examples and comparative examples was used to dye the cotton fabric. The dyeing method included the following steps:

[0129] The dyeing process is carried out at 45°C, and includes sequential immersion and oxidation. Immersion involves soaking the cotton fabric in the yellow reducing dye solution obtained in the examples and comparative examples for 10 minutes. Oxidation involves exposing the fabric to air for 5 minutes. The dyeing process consists of one pass. After dyeing, the cotton fabric is washed at a liquor ratio of 150:1 at 40°C for 10 minutes. The washing solution used is a 5 g / L soap flake solution. After washing, the fabric is dried to obtain the dyed fabric.

[0130] Color depth (K / S), dry and wet rubbing fastness, light fastness, and breaking strength were determined for undyed cotton fabrics and fabrics dyed with the dyeing solutions obtained in the examples and comparative examples.

[0131] Color depth is measured using a colorimeter;

[0132] The test for color fastness to dry and wet rubbing was conducted in accordance with GB / T 3920-2008 "Textiles - Tests for color fastness to rubbing".

[0133] The light fastness was tested in accordance with GB / T 8427-2019 "Textiles - Tests for color fastness to artificial light: Xenon arc".

[0134] After the light fastness test, the breaking strength of the fabric samples was tested. The test method was in accordance with GB / T 3923.1-2013 "Textiles - Tensile properties of fabrics - Part 1: Determination of breaking strength and elongation at break (strip method)". At least 3 fabric pieces were taken for each group for testing, and the average results were statistically analyzed.

[0135] The results of the above tests are shown in Table 2 below:

[0136] Table 2. Performance test data of fabrics obtained from dyeing in the examples and comparative examples.

[0137]

[0138]

[0139] Note: The performance test data of Examples 9-10 in Table 2 above are similar to those of Example 6.

[0140] As shown in Table 2 above, when cotton fabrics are dyed using the dyeing solution provided by this invention, a lightfastness test is performed, followed by a tensile strength test. The results show that the tensile strength of the fabric after dyeing and light exposure is similar to that before dyeing, and even slightly improved. This is likely because, with reduced fiber damage from the dye and reducing agent, 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione can form hydrogen bonds through its hydroxyl and amino groups, increasing the bonding strength between fibers. This not only prevents light brittleness but also slightly improves the fabric's strength. Furthermore, the fabrics dyed using this invention have a color depth (K / S) of over 3.2, wet and dry rubbing fastness of grade 4 or higher, and lightfastness of grade 6 or higher.

[0141] As can be seen from the data in Examples 1 to 7, when the component ratio of each component in the yellow reducing dyeing solution provided by the present invention satisfies the preferred ratio of 1 part 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione, 0.5 to 2 parts reducing agent, 0.2 to 0.5 parts sodium carbonate, and 200 to 300 parts solvent (Example 6), the dyed fabric has the highest average color depth, excellent dyeing ability, and at the same time, the color fastness to dry and wet rubbing reaches level 4 or above, the color fastness to light reaches level 6 or above, and the breaking strength is as high as 5N or above, resulting in better overall performance.

[0142] Based on the data from Example 8, replacing the alkali agent sodium carbonate with an equal amount of sodium hydroxide resulted in a significant decrease in color depth compared to Example 6 under strongly alkaline conditions, and the fiber strength was also significantly weakened. Therefore, sodium carbonate is the preferred alkali agent.

[0143] Comparative Examples 1 and 2 used sodium hydrosulfite and thiourea dioxide as reducing agents. Compared with Example 6, the color depth was significantly reduced, the light fastness was lower, and the tear strength was also reduced. This indicates that 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione is a weak reducing dye. Under the action of reducing agents (sodium hydrosulfite and thiourea dioxide) with stronger reducing power, the structure of the dye and fabric fibers may be damaged, resulting in the dyeing depth of Comparative Examples 1 and 2 being significantly lower than that of the Example. The dyeing method provided by the present invention can further improve the tear strength of dyed fabrics and improve the light brittleness of fabrics.

[0144] According to Comparative Examples 3-4 and 7, replacing some of the sodium sulfite reducing agent with other existing strong reducing agents, although the dyeing ability and breaking strength were slightly improved compared to Comparative Examples 1-2, which directly used sodium hydrosulfite and thiourea dioxide as reducing agents, the overall performance of the fabric was still lower than that of the fabric reduced by sodium sulfite alone, indicating that the use of strong reducing agents will damage the fibers of the fabric.

[0145] Comparative Example 5 is an existing process that uses vat yellow G to prepare the dyeing solution. As can be seen from the data of Comparative Example 5, the existing yellow vat dyeing process will damage the fibers of the fabric, and the fabric will show obvious light brittleness.

[0146] Comparative Example 6 uses Vat Yellow G to replace the weakly reducing dye 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione in this invention. Since Vat Yellow G contains an aromatic ring structure, it is easy to generate active substances under light, which will cause oxidative degradation of the fabric fibers and thus reduce the strength of the fibers.

[0147] In the dyeing solution provided in Comparative Example 8, the amount of reducing agent added was insufficient, which could not fully reduce 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione, resulting in a decrease in dye uptake and a significant reduction in color depth. At the same time, the dye molecules could not fully form hydrogen bonds, so they could not play a good reinforcing role on the fabric. However, under light conditions, the dye molecules would not affect the fiber structure by producing active substances, so the breaking strength of the fabric only decreased slightly.

[0148] II. Investigation of Optimal Dyeing Process Conditions

[0149] Below, the yellow reducing dyeing solution provided in Example 6 was used to dye cotton fabrics using different dyeing methods to explore the optimal dyeing process conditions, as shown in Examples 1 to 9.

[0150] Example of an effect 1.

[0151] A staining method comprising the following steps:

[0152] The cotton fabric was dyed at 45°C. The dyeing process included immersion dyeing and oxidation. Immersion dyeing involved soaking the cotton fabric in the yellow reducing dye solution obtained in Example 6 at a liquor ratio of 150:1 for 10 minutes. Oxidation involved exposing the fabric to air for 5 minutes. The dyeing process consisted of one pass. After dyeing, the cotton fabric was washed at a liquor ratio of 150:1 at 40°C for 10 minutes. The washing solution used was a 5 g / L soap flake solution. After washing, the fabric was dried to obtain the dyed fabric.

[0153] Example of effect 2.

[0154] A staining method, which differs from Example 1 only in that:

[0155] Cotton fabrics were dyed at 25°C, with an immersion time of 0.5 min and an oxidation time of 1 min.

[0156] Example of an effect 3.

[0157] A staining method, which differs from Example 1 only in that:

[0158] Cotton fabrics were dyed at 80℃, with an immersion time of 30 minutes and an oxidation time of 10 minutes.

[0159] Example of an effect 4.

[0160] A staining method, which differs from Example 1 only in that:

[0161] After dyeing, the cotton fabric is washed at a liquor ratio of 100:1, at a temperature of 30°C for 5 minutes. The washing solution used is a 1 g / L soap flake solution.

[0162] Example of an effect: 5.

[0163] A staining method, which differs from Example 1 only in that:

[0164] After dyeing, the cotton fabric is washed at a liquor ratio of 200:1, at a temperature of 50°C for 5 minutes, using a 10 g / L soap flake solution.

[0165] Example of an effect: 6.

[0166] A staining method, which differs from Example 1 only in that:

[0167] The cotton fabric was dyed at 60°C using the yellow reducing dyeing solution obtained in Example 7; the washing temperature after dyeing was 60°C and the time was 20 minutes.

[0168] Example of an effect: 7.

[0169] A staining method, which differs from Example 6 only in that:

[0170] There are 4 staining lanes.

[0171] Example of an effect: 8.

[0172] A staining method, which differs from Example 6 only in that:

[0173] There are 7 staining passes.

[0174] Example of an effect: 9.

[0175] A staining method, which differs from Example 6 only in that:

[0176] There are 10 staining passes.

[0177] The color depth (K / S), dry and wet rubbing color fastness, light fastness and breaking strength of the dyed fabric samples obtained in the above effect example were determined, and the test methods were carried out in accordance with the first part.

[0178] The performance test data is shown in Table 3 below:

[0179] Table 3. Performance test data of fabrics obtained from dyeing in Examples 1-9

[0180]

[0181] Based on the data from Examples 6-9 in Table 3 above, it is clear that increasing the number of dyeing passes does not significantly affect the breaking strength of the fabric, but mainly affects the color depth; the more passes, the higher the color depth. The highest dyeing depth can reach 9.5 (10 passes), and the color fastness to both dry and wet rubbing is above grade 4, while the light fastness can reach grade 6.

[0182] III. Dyeing Results for Fabrics of Different Fibers

[0183] Below, the yellow reducing dyeing solution provided in Example 6 and Comparative Example 5 were used to dye fabrics of different materials to explore its dyeing effect on different fabrics, as shown in Example 10 to 19.

[0184] Example of an effect: 10.

[0185] A staining method comprising the following steps:

[0186] The linen fabric was dyed at 45°C. The dyeing process included immersion dyeing and oxidation. Immersion dyeing involved soaking the linen fabric in the yellow reducing dye solution obtained in Example 6 for 10 minutes. Oxidation involved exposing the fabric to air for 5 minutes. The dyeing process consisted of one pass. After dyeing, the linen fabric was washed at a liquor ratio of 150:1 at 40°C for 10 minutes. The washing solution used was a 5 g / L soap flake solution. After washing, the fabric was dried to obtain the dyed fabric.

[0187] Example of an effect: 11.

[0188] A staining method, which differs from effect example 10 only in that:

[0189] Replace the linen fabric with an equal amount of silk fabric.

[0190] Example of an effect: 12.

[0191] A staining method, which differs from effect example 10 only in that:

[0192] Replace the linen fabric with an equal mass of cellulose fiber fabric.

[0193] Example of an effect: 13.

[0194] A staining method, which differs from effect example 10 only in that:

[0195] Replace the linen fabric with an equal amount of polyester fabric.

[0196] Example of an effect: 14.

[0197] A staining method, which differs from effect example 10 only in that:

[0198] Replace the linen fabric with an equal weight of nylon fabric.

[0199] Example of an effect: 15.

[0200] A staining method, which differs from effect example 10 only in that:

[0201] The yellow reducing staining solution obtained in Example 6 was replaced with an equal volume of the yellow reducing staining solution obtained in Comparative Example 5.

[0202] Example of an effect: 16.

[0203] A staining method, which differs from effect example 11 only in that:

[0204] The yellow reducing staining solution obtained in Example 6 was replaced with an equal volume of the yellow reducing staining solution obtained in Comparative Example 5.

[0205] Example of an effect: 17.

[0206] A staining method, which differs from effect example 12 only in that:

[0207] The yellow reducing staining solution obtained in Example 6 was replaced with an equal volume of the yellow reducing staining solution obtained in Comparative Example 5.

[0208] Example of an effect: 18.

[0209] A staining method, which differs from effect example 13 only in that:

[0210] The yellow reducing staining solution obtained in Example 6 was replaced with an equal volume of the yellow reducing staining solution obtained in Comparative Example 5.

[0211] Example of an effect: 19.

[0212] A staining method, which differs from effect example 14 only in that:

[0213] The yellow reducing staining solution obtained in Example 6 was replaced with an equal volume of the yellow reducing staining solution obtained in Comparative Example 5.

[0214] The color depth (K / S), dry and wet rubbing color fastness, and light fastness of the dyed fabric samples obtained from the above-mentioned effect examples were determined, and the test methods were carried out in accordance with the first part.

[0215] The performance test data is shown in Table 4 below:

[0216] Table 4. Performance test data of fabrics obtained from dyeing in Examples 10-19

[0217]

[0218] As shown in Table 4 above, when different fiber fabrics are dyed using the dyeing solution provided by this invention, flax, silk, and cellulose fiber fabrics can achieve a high color depth. The color depth of polyester and nylon fabrics is slightly lower than that of natural and regenerated fibers. However, compared with fabrics dyed using conventional vat yellow G, the color depth of different fabrics is significantly improved, the rubbing fastness is improved by 0.5-1 grade, and the light fastness is improved by 2-3 grades.

[0219] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A yellow reducing staining agent, characterized in that, It includes 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione and a reducing agent, wherein the reducing agent is sodium sulfite, and the mass ratio of the reducing agent to 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione is ≥0.2:

1.

2. The yellow reducing staining agent as described in claim 1, characterized in that, Includes the following components, calculated by parts by mass: 0.2 to 3 parts reducing agent and 1 part 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione.

3. A yellow reducing staining solution, characterized in that, Includes the yellow reducing staining agent and solvent as described in claim 1 or 2.

4. The yellow reducing staining solution as described in claim 3, characterized in that, The solvent includes water.

5. The yellow reducing staining solution as described in claim 4, characterized in that, Includes the following components, calculated by parts by mass: 1 part 5-hydroxy-3-aminopyridine-2,6-(1H,3H)-dione, 0.2 to 3 parts reducing agent, 0.1 to 1 part alkali agent, 100 to 500 parts water.

6. The yellow reducing staining solution as described in claim 5, characterized in that, The alkaline agent includes at least one of ammonia, sodium carbonate, and sodium bicarbonate.

7. A method for preparing the yellow reducing staining solution according to any one of claims 3 to 6, characterized in that, Includes the following steps: Mix all components thoroughly and heat at 10–80°C for 10–90 minutes to obtain the final product.

8. A dyeing method, wherein a fabric is dyed using the yellow reducing dyeing solution according to any one of claims 3 to 6, wherein the fabric includes at least one of hydrophilic fabric and hydrophobic fabric.

9. The staining method as described in claim 8, characterized in that, Includes at least one of the following (a) to (b): (a) The hydrophilic fabric includes at least one of cotton fabric, linen fabric, silk fabric, wool fabric, and cellulose fiber fabric; (b) The hydrophobic fabric includes at least one of leather fabric, polyester fabric, and nylon fabric.

10. The staining method as described in claim 8, characterized in that, Includes at least one of the following (c) to (e): (c) The staining temperature is 10–80°C; (d) The staining process includes sequential immersion and oxidation, wherein the immersion bath ratio is (100-200):1 and the time is 0.5-30 min, and the oxidation time is 1-10 min; (e) The number of staining passes is 1 to 15.

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