Vat dye suitable for chinlon fabric and dyeing method
By studying and optimizing the reducing dye composition and dyeing process of nylon fabrics, the problem of insufficient dye compatibility in dyeing of nylon fabrics is solved, and the dyeing effect with bright colors and excellent color fastness is achieved, especially under medium-temperature and high temperature conditions.
Patent Information
- Application Number
- CN202510610248.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-13
- Publication Date
- 2025-08-08
AI Technical Summary
In the prior art, the dyeing method of nylon fabrics has insufficient research on dye compatibility, resulting in uneven dyeing and poor color fastness, especially poor performance in dark dyeing, and it is difficult to achieve color stability during dyeing.
Select suitable yellow, red and blue reducing dye compositions, and optimize the dyeing process by studying the dependence of factors such as its molecular structural parameters, temperature, safety powder and electrolytes, and propose a reducing dye dye dyeing scheme suitable for nylon fabrics, including medium-temperature high-temperature dyeing technology, combined with soap boiling treatment to improve color fastness.
The reduction dye has good compatibility with nylon fabrics and bright dyeing color, especially the water-resistant fastness and friction fastness reach level 4-5 or above, solving the problems of uneven dyeing and insufficient color fastness.
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Figure CN120442081A_ABST
Abstract
Description
Technical Background
[0001] The invention relates to a vat dye suitable for nylon fabric and a dyeing method, belonging to the technical field of nylon fabric dyeing. Background Art
[0002] Nylon, the first commercially successful synthetic fiber, boasts excellent strength and high abrasion resistance, making it widely used in clothing, household fabrics, and industrial textiles. Although nylon is a synthetic fiber, its molecular ends contain amino or carboxyl groups, making it dyeable with acid dyes, reactive dyes, and disperse dyes.
[0003] Acid dyes contain water-soluble groups such as sulfonic acid and carboxyl groups. In acidic environments, they can form ionic bonds with dye anions. Furthermore, the dye molecules can form strong intermolecular forces and hydrogen bonds with amide groups and methylene chains in the nylon macromolecular chain, resulting in a strong affinity for nylon. This characteristic allows acid dyes to dye nylon quickly and with a high initial dyeing rate, but it can also lead to uneven dyeing. Their color fastness is generally less than ideal, and fixation treatment is often required. When dyeing nylon with reactive dyes, dark colors are difficult to achieve due to the limited amino group content at the end of the nylon molecular chain. Disperse dyes do not contain water-soluble groups, but due to their low molecular weight and excellent diffusion properties, they exhibit excellent coverage and dyeing uniformity on nylon. However, due to the weak binding force between the two, color fastness is poor when dyeing dark colors.
[0004] Vat dyes have the highest fastness of all dyes, a complete color spectrum, and vibrant colors, second only to basic dyes. They are suitable for dyeing and printing cotton, linen, and viscose fibers. Vat dyes are a type of dye that requires reduction to dye. They are insoluble in water and contain two or more carbonyl groups in their molecules. Under the action of an alkaline solution containing a reducing agent, the carbonyl groups are reduced to hydroxyl groups, making the dye soluble in the alkaline solution and forming a leuco sodium salt with an affinity for cellulose, which then dyes the fiber. After oxidation by air or an oxidant, the dye returns to its original insoluble state and becomes fixed to the fiber.
[0005] In order to develop high-quality dyeing technology for nylon, recently, there have been reports on the use of vat dyes for dyeing nylon fabrics. However, these reports have been limited to the discussion and research of dyeing technology, and no research or disclosure has been made on the compatibility of vat dyes for dyeing nylon. In actual production and processing, in order to meet the needs of various colors, it is inevitable to mix and match various dyes. During this process, the selected dyes must be compatible with each other, and their dyeing ability and dyeing rate must be similar. Therefore, the compatibility study of vat dyes for dyeing nylon is particularly important. The present invention systematically studies the structure-activity relationship of vat dyes for dyeing nylon fabrics, and reveals the various dyeing properties of vat dyes with different molecular structures for dyeing nylon fabrics. On this basis, the compatibility between the dyes is studied, and a vat dye mix and match scheme suitable for dyeing nylon fabrics is proposed. Summary of the Invention
[0006] The first object of the present invention is to provide a vat dye suitable for dyeing nylon fabrics.
[0007] The technical solution adopted by the present invention is as follows:
[0008] A vat dye suitable for nylon fabric, selected from any two or three of yellow vat dye, red vat dye, and blue vat dye, wherein: the yellow vat dye is selected from at least one of CI Vat Yellow 1 and CI Vat Yellow 2, the red vat dye is selected from at least one of CI Vat Red 10 and CI Vat Red 13, and the blue vat dye is selected from at least one of CI Vat Blue 4 and Vat Dye Blue DMG.
[0009] As the preferred technical solution:
[0010] The vat dye blue DMG is a compound commercial dye blue DMG produced by Jiangsu World Chemical Co., Ltd.
[0011] The present invention can select any two or three of yellow vat dye, red vat dye and blue vat dye, and the component selection and component dosage of the formula can be reasonably configured according to the required color.
[0012] When the dye is suitable for dyeing nylon fabric at medium temperature (70-75° C.), it is preferred to adopt a blending scheme of CI Vat Yellow 2, CI Vat Red 13 and CI Vat Blue 4.
[0013] When the dye is suitable for high temperature (90-95° C.) dyeing of nylon fabric, it is preferred to adopt a combination of CI Vat Yellow 1, CI Vat Red 10 and Vat Dye Blue DMG.
[0014] The present invention provides a vat dye suitable for nylon fabric. By screening vat dyes with different structures and dyeing nylon, the dependence of the vat dyes on factors such as temperature, electrolytes, and reducing agents (hydrocarbon) as well as dyeing properties such as lifting performance, dyeing rate and color fastness are studied. Finally, red, yellow and blue primary vat dyes with suitable performance are found. By studying their compatibility, a dyeing scheme is proposed. Dyeing practice shows that the vat dyes have excellent performance when applied to the dyeing of nylon fabric.
[0015] A second aspect of the present invention is to provide a method for dyeing nylon fabric using the above-mentioned vat dye, comprising the following steps:
[0016] Dyeing process prescription:
[0017]
[0018] Dyeing process:
[0019] Weigh vat dye, dispersant, hydrosulfite, caustic soda and anhydrous sodium sulfate, and dilute the materials with an appropriate amount of water. Add a specified amount of water into the dye vat, and add the dye, dispersant, hydrosulfite, caustic soda and anhydrous sodium sulfate in turn. After the dyeing machine runs for 3 to 5 minutes, put the fabric in, heat it up to the set temperature at a speed of 1 to 2°C / min for dyeing, dye at a constant temperature for 30 to 40 minutes, then cool it to room temperature, rinse with water for 5 to 10 minutes, and then boil with soap. After cleaning, take the fabric out of the vat.
[0020] Further:
[0021] The constant temperature dyeing is performed at 70-75°C for medium temperature dyeing and 90-95°C for high temperature dyeing.
[0022] The vat dyes, depending on the dyeing temperature, are: the vat dyes for medium-temperature dyeing are a combination of CI Vat Yellow 2, CI Vat Red 13 and CI Vat Blue 4; the vat dyes for high-temperature dyeing are a combination of CI Vat Yellow 1, CI Vat Red 10 and vat dye blue DMG.
[0023] The dispersant is selected from any one of dispersant NNO, dispersant MF, dispersant Reax 85A, etc.
[0024] The soap boiling process is as follows: after constant temperature dyeing is completed, the dye reduced during the dyeing process is oxidized and colored by sufficient contact with air, water is added again to a specified bath ratio, a specified amount of sodium carbonate and detergent are added, the temperature is raised to 95° C. and soap boiling is performed for 10 minutes. The soap boiling process recipe is: 2 g / L sodium carbonate, 1 g / L detergent, and a bath ratio of 5 to 20:1. After soap boiling, the temperature is lowered and water is added, and the vat is taken out after washing 2 to 3 times.
[0025] The detergent is any one of detergent 6501, detergent LS, detergent 209 (pancreas plus bleach T), etc.
[0026] The beneficial effects of the present invention are as follows:
[0027] The present invention has developed a vat dye composition through research and experiments. The selected vat dye is used for dyeing nylon, has good compatibility, is suitable for mixing in various proportions, has bright colors, simple dyeing process, and has excellent color fastness, especially water fastness and rubbing fastness basically reaching level 4-5 or above.
[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 The dependence of each dye on temperature when used for nylon dyeing.
[0030] Figure 2 This is the relationship between the aggregation factor and the optimal dyeing temperature.
[0031] Figure 3 This paper studies the effect of hydrosulfite dosage on the dyeing of nylon fabric with vat dyes.
[0032] Figure 4 This paper studies the effect of electrolyte dosage on the dyeing of nylon fabric with vat dyes.
[0033] Figure 5 Improve the dyeing performance of various dyes on nylon fabrics.
[0034] Figure 6 The dyeing rate curves of various dyes on nylon fabric at increasing temperatures are: (a) 90℃; (b) 80℃; (c) 70℃.
[0035] Figure 7 Comparison of reduction potential and temperature-increasing dyeing rate curves, including: (a) reduction potential diagram; (b) temperature-increasing dyeing curve.
[0036] Figure 8 The effects of different factors on the dyeing of two composite blue dyes: (a) temperature; (b) hydrosulfite; (c) electrolyte. DETAILED DESCRIPTION
[0037] Example 1: Screening of blended dyes
[0038] When dyes are applied to fibers, their molecular structures vary, resulting in different dyeing properties, including affinity (dye uptake), dye uptake rate, and dependence on various factors. When combining dyes, it is important to select dyes with similar dyeing properties (i.e., good compatibility). During the dyeing process, the dyes of each component are dyed simultaneously to avoid color instability caused by inconsistent dyeing.
[0039] To identify dyes with similar dyeing properties and compatible combinations, the present invention employed 20 different vat dyes and two mixed commercial dyes to dye nylon fabric. The dyes' dependence on factors such as temperature, electrolytes, and hydrosulfite, as well as dyeing properties such as lift and dye uptake, were systematically studied to identify dyes with matching properties. Furthermore, the compatibility of the selected primary dyes (red, yellow, and blue) was studied, ultimately yielding a dye combination suitable for nylon dyeing with excellent compatibility.
[0040] (1) Calculation of dye molecular structure parameters
[0041] To establish the intrinsic relationship between molecular structural parameters and dyeing performance, 20 commonly used vat dyes with different molecular structures were selected. Gaussian 16 software was used to calculate the molecular surface area, molecular volume, dipole moment, and polarizability of each dye using the B3LYP density functional theory (DFT) method at the 6-311G(d) basis set. The ClogP value (octanol / water partition coefficient) of each dye molecule was also calculated using the ClogP plug-in in ChemDraw in ChemOffice software. The results are shown in Table 1.
[0042] Table 1. Dye molecular structure parameters
[0043]
[0044]
[0045] Note: CI Vat Red 14 and CI Vat Red 15 are isomers of each other.
[0046] The above structural parameters of vat dyes provide an important basis for establishing the intrinsic connection between structure and dyeing performance. Generally speaking, the larger the molecular weight, molecular volume, and molecular area, the more likely the dye is to aggregate and the higher its temperature dependence during dyeing. Conversely, the temperature dependence is lower. The ClogP value reflects the hydrophilicity and hydrophobicity of the dye molecule: a larger value indicates greater hydrophobicity, and vice versa, a lower value indicates greater hydrophilicity. Therefore, the ClogP value directly affects the aggregation and solubility of the dye molecules, thereby affecting their dyeing ability and rate on nylon fabrics. The dipole moment reflects the polarity of the dye molecule: a larger dipole moment indicates greater polarity. The polarizability, on the other hand, reflects the degree to which the dye molecule is affected by an external electric field.
[0047] In summary, the influence of various structural parameters on dyeing performance and the influence rules will be analyzed one by one after the subsequent dyeing performance is measured.
[0048] (2) Temperature dependence
[0049] The 20 vat dyes in Table 1 were used to dye nylon fabric at different temperatures to observe the temperature dependence of each dye. The dyeing process is as follows:
[0050] Set the dye concentration to 2% (owf), hydrosulfite 20g / L, caustic soda 12g / L, dispersant MF 1g / L, bath ratio to 50:1, and heat to the specified temperature at 1°C / min. The temperature was varied to 70, 80, and 90°C, and the holding time was 30 minutes. The nylon fabric was dyed in a micro-pressure (sealed state) and the temperature dependence of each dye was observed. The results are as follows: Figure 1 shown.
[0051] from Figure 1 It can be seen that different dyes exhibit varying temperature dependence. Among yellow and orange dyes, CI Vat Yellow 33 and CI Vat Orange 1 achieve their maximum K / S values at moderate temperatures, while the K / S values of the remaining dyes continuously increase with increasing temperature. Comparatively, CI Vat Yellow 2 exhibits relatively little change in color depth with increasing temperature, demonstrating a relatively low temperature dependence. For red dyes, with the exception of CI Vat Red 10, whose K / S value gradually increases with temperature, the K / S values of the remaining dyes show an initial increase followed by a decrease, reaching their highest value in the moderate temperature range. For dark dyes, with the exception of CI Vat Green 1, which exhibits optimal dyeing results at moderate temperatures, the K / S values of the remaining dyes continuously increase with increasing temperature, making them high-temperature dyes. Notably, CI Vat Blue 4 is susceptible to excessive reduction reactions at high temperatures, resulting in changes in color depth, and can only be dyed at moderate temperatures.
[0052] The temperature dependence of dyeing varies depending on the dye's molecular structure. It is well known that the greater the degree of dye aggregation, the greater the dependence on temperature. Generally speaking, the larger the molecular surface area, the easier it is for the dye to aggregate. The lipid-water partition coefficient (ClogP) of a dye is an important indicator to measure its hydrophobicity. The larger the ClogP value, the more hydrophobic the dye is, and the easier it is to precipitate from the aqueous solution and aggregate. In addition, the better the molecular coplanarity, the easier it is to aggregate. Molecular coplanarity can be measured by the molecular model height (H) of the optimized structure, that is, the ratio of molecular volume to surface area. The smaller the ratio (that is, the lower the side view height), the better the coplanarity of the dye molecules, and vice versa.
[0053] Based on the above theoretical inferences and combined with the results of structural parameter calculation data, a mathematical function that reflects the tendency and ability of aggregation is constructed, which is called the aggregation factor. See formula (1).
[0054]
[0055] In formula (1), S is the molecular surface area, H is the height of the optimized molecular model, and V is the molecular volume. ClogP is the lipid-water partition coefficient of the dye (calculated as the octanol / water partition coefficient).
[0056] Formula (1) is used to calculate the aggregation factor of each dye. The results are as follows: Figure 2 shown.
[0057] according to Figure 2 Analysis shows that there is a strong correlation between the aggregation factor of dyes and their temperature dependence. When the aggregation factor is large, the dye exhibits a strong tendency to aggregate. Therefore, these dyes generally require higher temperatures for optimal disaggregation and dye uptake, making them suitable for high-temperature dyeing. For example, dyes such as CI Vat Yellow 1, CI Vat Yellow 2, CI Vat Orange 9, CI Vat Orange 11, CI Vat Red 10, CI Vat Brown 1, CI Vat Green 3, and CI Vat Black 8 have large aggregation factors and require high temperatures to achieve ideal dye depth. Conversely, dyes with smaller aggregation factors have a lower tendency to aggregate and easily disaggregate into single molecules for dyeing onto fabric at lower temperatures, making them suitable for dyeing at moderate temperatures. Examples include CI Vat Green 1, CI Vat Yellow 33, and most red vat dyes. Excessively high temperatures for these dyes actually reduce their color depth, consistent with the principle of dyeing thermodynamics: higher temperatures result in lower equilibrium dye uptake. Therefore, during the dyeing process, the dyeing temperature can be appropriately selected based on the aggregation characteristics of the dye to achieve optimal dyeing results.
[0058] (3) Effect of hydrosulfite dosage on dyeing
[0059] Through the above research, the optimal dyeing temperature of each dye was obtained. Based on the optimal dyeing temperature of the dye, the amount of hydrosulfite was changed (the mass ratio of hydrosulfite to caustic soda was controlled to be 5:3), the dye concentration was set to 2% (owf), the dispersant MF was 1g / L, the bath ratio was 50:1, the temperature was raised to the specified temperature at 1℃ / min, the holding time was 30min, and the nylon fabric was micro-pressure (closed state) dyed to observe the effect of the amount of hydrosulfite on dyeing. The results are as follows Figure 3 shown.
[0060] from Figure 3 As can be seen, as the amount of sodium hydrosulfite gradually increases, the color depth of the dye sample begins to rise, then slowly declines or remains stable after reaching a certain concentration. At the same dye concentration (2% owf), the optimal sodium hydrosulfite dosage for most vat dyes is 10g / L. For a few dyes, such as CI Vat Yellow 1, CI Vat Orange 1, CI Vat Orange 9, CI Vat Orange 2, and CI Vat Orange 11, the optimal sodium hydrosulfite dosage is 15g / L.
[0061] The molecular structure of a dye affects the ease of reduction. Generally speaking, indigo and xanthrone vat dyes have lower absolute values of leuco potential, making them easier to reduce. Anthraquinone vat dyes, on the other hand, have higher absolute values of leuco potential, making them more difficult to reduce. Polyphenyl-nucleated fused-ring anthrone and aminoanthrone dyes are the most difficult to reduce. The six yellow-orange vat dyes mentioned above, which use a high amount of hydrosulfite, all have anthraquinone, dibenzopyrenequinone, and pyreneanthrone structures, making them more difficult to reduce.
[0062] (4) Electrolyte dependence
[0063] The optimal dosage of hydrosulfite (the mass ratio of hydrosulfite to caustic soda is 5:3) and dyeing temperature obtained from the above study were used. The dye concentration was set to 2% (owf), the dispersant MF was 1g / L, the bath ratio was 50:1, the temperature was raised to the specified temperature at 1°C / min, the holding time was 30min, the amount of electrolyte (sodium sulfate) added was changed, and the nylon fabric was micro-pressure (closed state) dyeing was performed. The results are shown as follows: Figure 4 shown.
[0064] From above Figure 4As can be seen, the addition of electrolytes promotes dyeing to varying degrees, but generally not significantly. In comparison, five dyes—CI Vat Violet 3, CI Vat Red 15, CI Vat Red 14, CI Vat Orange 9, and CI Vat Blue 4—are more sensitive to the dyeing-promoting effect of electrolytes. In terms of molecular weight, these dyes have relatively small molecular weights (421, 412, 412, 406, and 442, respectively), and the intermolecular forces between them and nylon fibers are relatively weak. Therefore, the addition of electrolytes has a more pronounced dyeing-promoting effect. The other dyes have larger molecular weights and stronger affinity with nylon fibers, so the electrolyte effect is less pronounced.
[0065] (5) Enhancement
[0066] Yellow (high temperature type) and red (medium temperature type) dyes suitable for dyeing at the same temperature were selected, and dye solutions with different initial concentrations were prepared respectively. The optimal amount of hydrosulfite (hydrosulfite caustic soda mass ratio of 5:3) and dyeing temperature obtained from the above study were used. Dispersant MF was 1g / L, no electrolyte was added, the bath ratio was 50:1, the temperature was raised to the specified temperature at 1℃ / min, and the holding time was 30min. The nylon fabric was then micro-pressed (sealed state) dyed. The results are as follows. Figure 5 shown.
[0067] From above Figure 5 It can be seen that the color depth of the dye shows a continuous upward trend with increasing dye dosage and tends to stabilize after reaching a certain concentration. There are significant differences in the lifting performance between different dyes, which are mainly related to two factors: the lipid-water partition coefficient (ClogP) of the dye and the dye molecular weight. Dyes with higher ClogP values are more hydrophobic and have a better affinity with nylon fibers, thus showing better lifting performance. Due to the relatively compact structure of nylon fibers, the smaller the molecular weight of the vat dye, the easier it is to diffuse into the nylon fiber, which helps to increase the lifting performance.
[0068] Based on this, this paper uses the ratio of lipid-water partition coefficient (ClogP) to molecular weight as an important measurement indicator. Table 2 below lists Figure 5 The ratio of the lipid-water partition coefficient (ClogP) to the molecular weight of the vat dye species involved.
[0069] Table 2. Ratio of CLogP to Molecular Weight of Vat Dyes
[0070] dye CLogP*100 / molecular weight dye CLogP*100 / molecular weight CI Vat Yellow 1 1.59 CI Vat Red 1 1.90 CI Vat Yellow 2 1.62 CI Vat Red 13 1.54 CI Vat Orange 9 1.90 CI Vat Red 14 1.03 CI Vat Orange 11 1.37 CI Vat Red 15 1.03 CI Vat Brown 1 1.37 CI Vat Red 29 1.13 CI Vat Red 31 1.05 CI Vat Violet 3 2.00 .
[0071] The ratio data in Table 2 shows that larger ratios generally indicate better lift. For example, Vat Red 1 and Vat Violet 3 have significantly higher ratios than Vat Red 13, Vat Red 14, Vat Red 15, Vat Red 29, and Vat Red 31, resulting in higher lift. Among the yellow dyes, the order of ratios is Vat Orange 9, Vat Yellow 2, Vat Yellow 1, Vat Orange 11, and Vat Brown 1, which corresponds to the order of lift. Therefore, the larger the hydrophobic constant and the smaller the molecular weight, the better the lift for nylon fibers. When combining colors, choose dyes with similar ratios to achieve similar lift.
[0072] (6) Temperature rise dyeing rate curve
[0073] The optimal dosage of insurance powder (the mass ratio of insurance powder to caustic soda is 5:3) and dyeing temperature obtained from the above research were used, and the dye concentration was set to 2% (owf), dispersant MF 1g / L, and bath ratio to 50:1. For each dye, 10-11 groups of identical dye solutions were prepared, heated at 1°C / min, and kept warm for 30 minutes. During this period, a dye sample was taken out every 10 minutes, and post-treated with the same oxidation and soaping methods. After natural drying, the color depth value (K / S value) of the dye sample was measured to draw a temperature increase dyeing rate curve. Because the dyeing temperature has a great influence on the dyeing rate, the samples were grouped and plotted according to medium and high temperature dyeing temperatures. The results are shown in the figure below. Figure 6 shown.
[0074] analyze Figure 6 By comparing the data in the previous section and the molecular structure parameters of the dyes, it was found that when the dyeing temperature was the same, the dye uptake rate was related to the molecular weight of the dye. Dyes with larger molecular weights took longer to dye, such as Vat Yellow 33, Vat Orange 11, and Vat Black, with molecular weights of 832, 646, and 665, and took 30 or 40 minutes to reach equilibrium after being heated to 80°C or 90°C, respectively. On the other hand, dyes with smaller molecular weights, such as Vat Orange 9, Vat Red 14, Vat Red 15, and Vat Violet 3, with molecular weights of 406, 412, 412, and 421, took faster uptake, reaching equilibrium after being heated to 80°C or 90°C for 10 minutes, respectively. But there are exceptions. For example, Vat Red 29 and Vat Brown 1, although they have large molecular weights of 602 and 646 respectively, have fast dyeing rates and basically reach equilibrium after reaching 80℃ or 90℃. Vat Red 1 and Vat Yellow 1, although they have small molecular weights of only 393 and 408, have slow dyeing rates. The former has not reached equilibrium after 70 minutes at 80℃, while the latter reaches equilibrium after 40 minutes at 90℃.
[0075] It is speculated that the dyeing rate of vat dyes may be related to the reduction rate in addition to the molecular weight. In order to observe the relationship between the reduction rate and the dyeing rate, a red dye suitable for dyeing at a medium temperature of 80°C was selected for research. The dye concentration was set to 2% (owf), the temperature was 40°C, the amount of hydrosulfite was 15g / L, and the amount of caustic soda was 9g / L. The reduction potential was tested at 2min, 5min, 10min, and 15min of reduction, respectively. The results are as follows: Figure 7 shown.
[0076] During the reduction process of vat dyes, as the reduction time increases, the dye is continuously reduced to a leuco form. The vat dye concentration decreases, and the potential value gradually decreases (the absolute value increases). However, as the hydrosulfite is gradually consumed, the potential value gradually increases (the absolute value decreases). The potential value in the solution is determined by the concentrations of the vat dye and the hydrosulfite. Analysis of the trend of dye reduction potential changes reveals that the reduction potential of some dyes, such as CI Vat Red 29, CI Vat Red 14, and CI Vat Red 15, first decreases and then increases with prolonged reduction time. This indicates that the vat dyes are continuously reduced. After 10 minutes, the hydrosulfite concentration is clearly insufficient, and the potential begins to rise again. This indicates that this type of dye has a faster reduction rate, resulting in a faster dyeing rate. Dyeing equilibrium is reached after 10 minutes of incubation at 80°C. The potential value of CI Vat Red 13 begins to decrease, but remains at a similar level after 15 minutes, indicating that the amount of hydrosulfite used is sufficient and the reduction rate is relatively slow. The potential values of CI Vat Violet 3 and CI Vat Red 31 remained similar as the reduction time increased, indicating a relatively sufficient concentration of hydrosulfite and a slow reduction rate. The dyeing rates of these three dyes were slow, reaching equilibrium after 20 minutes at 80°C. CI Vat Red 1, on the other hand, showed a continuous downward trend in potential value, indicating the slowest reduction rate. Consequently, its dyeing rate was also the slowest, not reaching equilibrium after 70 minutes at 80°C, and the color depth of the dyed sample showed an increasing trend.
[0077] (7) Compatibility of dyes
[0078] The above-mentioned structure-activity relationship research has provided a more comprehensive understanding of the dyeing properties of the series of vat dyes. According to the temperature effect, dyes can be divided into two categories: medium-temperature and high-temperature, which are suitable for medium-temperature and high-temperature dyeing respectively. In order to meet the needs of color matching, further research is needed on the compatibility of dyes. Among the medium-temperature series of vat dyes, CI Vat Red 13 and CI Vat Blue 4 have relatively close performances. Although CI Vat Yellow 2 is a high-temperature type, it is also suitable for medium temperatures because it is not very sensitive to temperature. Its dyeing rate and lifting properties (ClogP to molecular weight ratio) are similar to those of the first two dyes. Therefore, CI Vat Red 13, CI Vat Blue 4 and CI Vat Yellow 2 can be used as medium-temperature primary colors for subsequent compatibility tests. However, no blue varieties have been found in the high-temperature group of dyes. In order to find blue dye varieties suitable for high-temperature dyeing, compound vat dye products on the market (Vat Blue 5508, Vat Blue DMG) were selected for further exploration, and their dependence on temperature, insurance powder and electrolyte was evaluated.
[0079] The following experimental method was used to sequentially change the temperature, amount of hydrosulfite and electrolyte, and measure the K / S value of the dyed sample. The test results are as follows Figure 8 shown.
[0080] Temperature: Set the dye concentration to 2% (owf), hydrosulfite 20g / L, caustic soda 12g / L, dispersant MF 1g / L, and bath ratio to 50:1. Raise the temperature at 1°C / min to the specified temperature. Repeat the temperature cycle through 70, 80, and 90°C, with a holding time of 30 minutes. Perform micro-pressure (enclosed) dyeing on nylon fabric.
[0081] Insurance powder: Based on the optimal dyeing temperature of the dye, the amount of insurance powder was changed (the mass ratio of insurance powder to caustic soda was controlled at 5:3), the dye concentration was set to 2% (owf), the dispersant MF was 1g / L, the bath ratio was 50:1, the temperature was raised to the specified temperature at 1°C / min, the holding time was 30min, and the nylon fabric was micro-pressure (closed state) dyeing was performed.
[0082] Electrolyte: Based on the optimal hydrosulfite dosage and dyeing temperature obtained above, the dye concentration was set to 2% (owf), the dispersant MF was 1 g / L, the bath ratio was 50:1, the temperature was raised to the specified temperature at 1°C / min, and the holding time was 30 min. The amount of electrolyte (sodium sulfate) added was changed, and the nylon fabric was micro-pressure (closed state) dyeing was performed.
[0083] from Figure 8As can be seen, both composite blue dyes achieve high color depths at higher temperatures, making them suitable for high-temperature dyeing. However, because Vat Blue 5508 contains CI Vat Blue 4, it can also suffer from over-reduction during high-temperature dyeing, causing a reddish cast. Analysis revealed that Vat Blue DMG exhibits similar properties to CI Vat Yellow 1, including its dependence on factors such as temperature and hydrosulfite. Therefore, Vat Blue DMG was selected as one of the three high-temperature primary colors for compatibility testing.
[0084] (8) Color fastness performance
[0085] According to the optimized dyeing process, nylon fabrics were dyed respectively, and then washed with oxidized soap and dried to obtain dyed samples.
[0086] Dyeing process: Using the optimal sodium hydrosulfite dosage (the mass ratio of sodium hydrosulfite to caustic soda is 5:3) and dyeing temperature obtained from the above research, the dye concentration is set to 2% (owf), the dispersant MF is 1g / L, the bath ratio is 50:1, the temperature is raised to the set temperature at a rate of 1°C / min, and the temperature is kept for 30 minutes.
[0087] Oxidation soap boiling process: After constant temperature dyeing is completed, the dye reduced during the dyeing process is oxidized and colored through full contact with air, and water is added again to the specified bath ratio, and the specified amount of sodium carbonate and detergent are added. The temperature is raised to 95℃ and soaped for 10 minutes. The soap boiling process prescription is: sodium carbonate 2g / L, detergent 1g / L, bath ratio of 20:1. After soap boiling, the temperature is lowered and water is added. After washing 2 to 3 times, it is taken out of the tank.
[0088] Fastness properties were measured according to GB / T3920-2008 "Textiles—Tests for Color Fastness—Color Fastness to Rubbing," GB / T3921-2008 "Textiles—Tests for Color Fastness—Color Fastness to Washing with Soap," and GB / T8427-2008 "Textiles—Tests for Color Fastness—Color Fastness to Artificial Light: Xenon Arc Fading Light." The test results are shown in Table 3.
[0089] Table 3. Color fastness properties of nylon fabrics dyed with vat dyes
[0090]
[0091] According to the data in the above table, except for three dyes with relatively low light fastness, the color fastness performance of nylon dyed with vat dyes is excellent. Its soap washing and rubbing fastness basically reach above 4-5, and most of them even reach level 5.
[0092] Application examples:
[0093] Based on the above structure-activity relationship research results, nylon fabrics were blended and dyed using CI Vat Red 13, CI Vat Blue 4, and CI Vat Yellow 2, both suitable for medium-temperature dyeing, and CI Vat Red 10, CI Vat Yellow 1, and the commercially available blue DMG, both suitable for high-temperature dyeing. Each dye combination was blended in different ratios and dyed at three different temperatures. The compatibility of the two dye combinations was evaluated by observing the temperature sensitivity of the color phases of the blended dyes.
[0094] Dyeing process conditions: Set the dye concentration to 2% (owf), the hydrosulfite dosage to 15g / L, the caustic soda dosage to 9g / L, the dispersant MF to 1g / L, the bath ratio to 50:1, and heat to the set temperature at a rate of 1°C / min. The dyeing temperatures for the medium-temperature group were 65, 70, and 75°C, respectively, and the high-temperature group were 85, 90, and 95°C, respectively. The holding time was 30 minutes for each group. The three dye dosage ratios were controlled at 3:1:1, and nylon fabrics were micro-pressure dyed (enclosed). After dyeing, soaping and other post-treatments were performed, and the dyed samples were measured after natural drying. The dyeing results are shown in Tables 4-5.
[0095] Table 4. Color parameters of medium temperature dyed nylon fabrics
[0096]
[0097] Table 5. Color parameters of high-temperature dyed fabrics
[0098]
[0099]
[0100] The data in Tables 4-5 show that, regardless of the ratio of the two dye sets used for blending at different temperatures, the hue values show minimal variation, and the shade remains relatively stable. As the dyeing temperature increases, the fabric's color depth increases moderately, the L value decreases, and the fabric's color becomes richer, while other parameters exhibit relatively little variation. This demonstrates that both dye sets exhibit good compatibility and are suitable for blending nylon.
Claims
1. A vat dye suitable for nylon fabrics, characterized by: Any two or three selected from yellow vat dyes, red vat dyes, and blue vat dyes, wherein: the yellow vat dye is selected from at least one of CI Vat Yellow 1 and CI Vat Yellow 2, the red vat dye is selected from at least one of CI Vat Red 10 and CI Vat Red 13, and the blue vat dye is selected from at least one of CI Vat Blue 4 and Vat Dye Blue DMG.
2. The vat dye suitable for nylon fabric according to claim 1, characterized in that: The vat dye blue DMG is a compound commercial dye blue DMG produced by Jiangsu World Chemical Co., Ltd.
3. The vat dye suitable for nylon fabric according to claim 1, characterized in that: When the dye is suitable for dyeing nylon fabric at a medium temperature of 70-75° C., a blending scheme of CI Vat Yellow 2, CI Vat Red 13 and CI Vat Blue 4 is adopted.
4. The vat dye suitable for nylon fabric according to claim 1, characterized in that: When the dye is suitable for dyeing nylon fabric at a high temperature of 90-95° C., a blending scheme of CI Vat Yellow 1, CI Vat Red 10 and Vat Dye Blue DMG is adopted.
5. A method for dyeing nylon fabric using the vat dye according to claim 1, characterized in that: Dyeing process prescription: Dyeing process: Weigh vat dye, dispersant, hydrosulfite, caustic soda and anhydrous sodium sulfate, and dilute the materials with an appropriate amount of water. Add a specified amount of water into the dye vat, and add the dye, dispersant, hydrosulfite, caustic soda and anhydrous sodium sulfate in turn. After the dyeing machine runs for 3 to 5 minutes, put the fabric in, heat it up to the set temperature at a speed of 1 to 2°C / min for dyeing, dye at a constant temperature for 30 to 40 minutes, then cool it to room temperature, rinse with water for 5 to 10 minutes, and then boil with soap. After cleaning, take the fabric out of the vat.
6. The method for dyeing nylon fabric with a vat dye according to claim 5, characterized in that: The constant temperature dyeing is performed at 70-75°C for medium temperature dyeing and 90-95°C for high temperature dyeing.
7. The method for dyeing nylon fabric with a vat dye according to claim 6, characterized in that: According to the dyeing temperature, the vat dye for medium temperature dyeing is a combination of CI Vat Yellow 2, CI Vat Red 13 and CI Vat Blue 4, and the vat dye for high temperature dyeing is a combination of CI Vat Yellow 1, CI Vat Red 10 and Vat Dye Blue DMG.
8. The method for dyeing nylon fabric with a vat dye according to claim 5, characterized in that: The dispersant is selected from any one of dispersant NNO, dispersant MF, and dispersant Reax 85A.
9. The method for dyeing nylon fabric with a vat dye according to claim 5, characterized in that: The soap boiling process is as follows: after constant temperature dyeing is completed, the dye reduced during the dyeing process is oxidized and colored by sufficient contact with air, water is added again to a specified bath ratio, a specified amount of sodium carbonate and detergent are added, the temperature is raised to 95° C. and soap boiling is performed for 10 minutes. The soap boiling process recipe is: 2 g / L sodium carbonate, 1 g / L detergent, and a bath ratio of 5 to 20:
1. After soap boiling, the temperature is lowered and water is added, and the vat is taken out after washing 2 to 3 times.
10. The method for dyeing nylon fabric with a vat dye according to claim 9, characterized in that: The cleaning agent is any one of cleaning agent 6501, cleaning agent LS, and cleaning agent 209.