A brilliant blue vat dye composition having high fastness to chlorine bleaching

Abstract

The application belongs to the fine chemical industry field, and particularly relates to a high-chlorine bleaching high-weather-resistant vat blue dye which is composed of 15-20% of dye monomer A, 12-18% of dye monomer B, 7-15% of dye monomer C and a dispersing agent by weight percentage. The vat blue dye prepared by the technical scheme has excellent comprehensive color fastness, the chlorine bleaching fastness reaches grade 4-5, the light fastness reaches grade 7-8, the washing fastness and the perspiration fastness both reach grade 4-5, meanwhile, the vat blue dye has excellent color light stability during storage, can effectively reduce the color light deviation to the red light direction during storage of dyed fabrics, and solves the problems of the chlorine bleaching resistance, the high weather resistance and the color light deviation to the red light direction during storage of the existing vat blue dye.

Description

Technical Field

[0001] This invention belongs to the field of fine chemicals, specifically relating to a composition of a bright blue vat dye with high chlorine bleach fastness. Background Technology

[0002] Commonly used dyes for cellulosic fibers include reactive dyes, vat dyes, direct dyes, sulfur dyes, and ice dyes. Due to the shortcomings of direct dyes, sulfur dyes, and ice dyes, such as incomplete color spectrum and poor overall color fastness, reactive dyes and vat dyes are currently the main dyeing methods used in industrial production.

[0003] Compared with vat dyes, reactive dyes have advantages such as a complete color spectrum, relatively simple dyeing process, and lower cost. However, their light fastness, chlorine bleach fastness, and overall color fastness to light, perspiration, and washing are relatively poor. Therefore, in fields such as khaki casual fabrics, workwear fabrics, medical textiles, and military clothing, where high fabric durability is required, vat dyes still have irreplaceable advantages.

[0004] Vat dyes possess excellent overall colorfastness, including wash fastness, rubbing fastness, and light fastness. However, blue vat dyes still have certain shortcomings in terms of chlorine bleaching fastness, lightfastness, and color stability during storage. For example, commonly used blue vat dyes such as Vat Blue 1, Vat Blue 4, Vat Blue 5, Vat Blue 6, and Vat Blue 14 generally have a chlorine bleaching fastness of only grade 1 to 3, and are prone to color changes after treatment with chlorine bleach. Furthermore, some blue vat dyes exhibit poor color stability during long-term storage, and are prone to a reddish shift in color under normal temperature and humidity or high humidity conditions, a phenomenon commonly referred to in the industry as "reddening upon contact with water."

[0005] In recent years, with the development of medical textiles, workwear fabrics, outdoor textiles, and high-quality home textiles, the market has placed higher demands on the chlorine bleaching resistance, lightfastness, and storage stability of vat blue dyes. While existing brilliant blue vat dyes can impart vibrant colors and high overall colorfastness to fabrics in practical applications, their molecular structure presents certain contradictions in terms of chlorine bleaching resistance, lightfastness, and color stability during storage. On the one hand, brilliant blue vat dyes typically rely on a large conjugated system to achieve high color saturation, but this structure is susceptible to structural changes under strong oxidizing environments caused by chlorine-containing oxidants, leading to a decrease in chlorine bleaching resistance. On the other hand, some vat blue dyes are prone to molecular structural changes, crystal transformations, or changes in intercomponent interactions during long-term light exposure or storage, resulting in color shift and affecting the overall color stability of the dyed fabrics.

[0006] Currently, single-structure vat dyes cannot simultaneously meet the comprehensive requirements of vibrant blue color, high resistance to chlorine bleaching, high lightfastness, and long-term storage stability. Therefore, it is necessary to construct multi-component vat dye compositions with synergistic effects through the rational screening of dye molecular structures and optimization of compounding systems, in order to achieve a simultaneous improvement in overall color fastness and light stability. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a bright blue vat dye composition with high chlorine bleach fastness, so as to solve the problem that it is difficult to simultaneously achieve the chlorine bleach fastness, lightfastness and color stability of existing vat blue dyes during storage.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A bright blue vat dye composition with high chlorine bleach fastness, comprising the following components: A dye monomer A of chemical formula (1) in a weight percentage of 15-20%;

[0009] A dye monomer B of chemical formula (2) in a weight percentage of 12-18%;

[0010] A dye monomer C of chemical formula (3) in a weight percentage of 7-15%;

[0011] The remainder are dispersants.

[0012] Preferably, the dye composition comprises the following components: 16-19% by weight of dye monomer A (CI Vat Violet 9) as shown in chemical formula (1)

[0013] A 13-17% by weight of dye monomer B (CI Vat Green 1) as shown in chemical formula (2)

[0014] 8-13% by weight of dye monomer C (CI Vat Blue 6) as shown in chemical formula (3)

[0015] The remainder are dispersants.

[0016] Furthermore, the dye composition comprises the following components: 17-18% by weight of dye monomer A (CI Vat Violet 9) as shown in chemical formula (1) A 14-16% by weight of dye monomer B (CI Vat Green 1) as shown in chemical formula (2) 9-11% by weight of dye monomer C (CI Vat Blue 6) as in chemical formula (3) The remainder are dispersants.

[0017] Preferably, the dispersant is one or a mixture of two of lignin sulfonates, such as sodium lignin sulfonate and methylnaphthalene sulfonate formaldehyde condensate. More preferably, the dispersant is composed of methylnaphthalene sulfonate formaldehyde condensate (MF) and lignin sulfonate dispersant TS-3 (for example, lignin sulfonate TS-3 from Jinan Shengquan Group Co., Ltd. can be selected), wherein the mass ratio of MF to TS-3 is 1:1.

[0018] Preferably, the total mass of dye monomer A, dye monomer B, and dye monomer C accounts for 34-53% of the weight percentage of the dye composition.

[0019] Preferably, the total mass of dye monomer A, dye monomer B, and dye monomer C accounts for 40-47% of the weight percentage of the dye composition.

[0020] Those skilled in the art will understand that the above weight percentages are calculated on a dry basis.

[0021] The high chlorine bleach fastness bright blue vat dye composition provided by this invention can be prepared according to the following steps: According to the formula ratio, filter cakes of dye monomer A, dye monomer B, and dye monomer C, along with a composite dispersant composed of methylnaphthalenesulfonic acid formaldehyde condensate (MF) and lignin sulfonate dispersant TS-3 in a 1:1 mass ratio, were weighed and added to a pulping pot for mixing and pulping to obtain a uniform and stable slurry. The obtained slurry was then fed into a high-efficiency sand mill for grinding, controlling the grinding endpoint to ensure that the particle size of the dye slurry met the process requirements, where D90 ≤ 1 μm. After grinding, impurities were removed by filtration, and then the slurry was dried using a spray drying process, controlling the spray drying temperature at 130 ℃, to obtain a commercially available bright blue vat dye composition with high chlorine bleach fastness.

[0022] In this invention, if there is a conflict between the Chinese name and the structural formula of a compound, the structural formula shall prevail; except where the structural formula is obviously incorrect, such as if there is a discrepancy between the structural formula and the CAS number, the CAS number shall prevail.

[0023] The beneficial effects of this invention are as follows: the high chlorine bleach fastness bright blue vat dye composition prepared using the technical solution of this invention exhibits excellent overall color fastness. This invention optimizes overall color performance by constructing a specific ternary compound system using vat violet 9, vat green 1, and vat blue 6, utilizing the structural complementarity and synergistic effects between different dye monomers. Specifically, vat blue 6, as the main color component, imparts a bright blue overall color to the dye composition; vat violet 9 and vat green 1, through their overall color-regulating effect, effectively improve the insufficient color stability in single blue vat dye systems, while simultaneously enhancing the structural stability of the dye composition in oxidizing environments and during long-term storage.

[0024] By further optimizing the mass ratio of the three dye monomers, a balance is achieved in terms of color matching, oxidation stability, and fiber adsorption performance among the components. While maintaining a vibrant blue color and overall color purity, the dye composition's resistance to chlorine bleaching, lightfastness, and color stability during storage are improved. The vat blue dye prepared using this invention achieves a chlorine bleaching fastness of grade 4 or higher and a lightfastness of grade 7 or higher. Under normal temperature and humidity storage conditions, it effectively reduces color changes in dyed fabrics during storage, improves the appearance stability and product consistency of dyed fabrics, and meets the application requirements of high-quality textiles for high chlorine bleaching resistance, high lightfastness, and high storage stability.

[0025] The dye A used in this invention is CI Vat Violet 9, dye monomer B is CI Vat Green 1, and dye monomer C is CI Vat Blue 6. All dyes A, B, and C can be commercially available products, such as CI Vat Violet 9, CI Vat Green 1, and CI Vat Blue 6 produced by Jiangsu Yabang Dyestuff Co., Ltd.

[0026] Color Index (CI) means "Dye Index Number," and it is an internationally recognized name for dyes. Attached Figure Description

[0027] Figure 1 This is a graph showing the average Da variation of Examples 1-5 and Comparative Examples 1-5 under normal temperature and humidity storage conditions. Detailed Implementation

[0028] The present invention is illustrated below with reference to examples, but is not intended to limit the invention. Any simple substitutions or modifications made to the present invention by those skilled in the art are within the scope of the technical solutions protected by this invention.

[0029] I. Raw material ratio of the example According to the data shown in Table 1, filter cakes of dye monomers A, B, and C, along with a composite dispersant composed of methylnaphthalenesulfonic acid formaldehyde condensate (MF) and lignin sulfonate dispersant TS-3 in a 1:1 mass ratio, were weighed according to the specified proportions. These were added to a pulping pan, mixed, and pulped. The mixture was then ground in a high-efficiency sand mill until the desired particle size (D90 ≤ 1 μm) was reached. After grinding, the mixture was filtered and spray-dried to obtain the commercial dye. This invention uses only dye monomers A, B, and C, along with the composite dispersant, without adding defoamers, wetting agents, or other auxiliary agents.

[0030] Table 1 Raw material ratios in each embodiment

[0031] II. Comparative Raw Material Ratio According to the formulation shown in Table 2, dye monomer A (vapor violet 1), dye monomer B (vapor green 3), dye monomer C (vapor blue 4), and a composite dispersant composed of methylnaphthalenesulfonic acid formaldehyde condensate (MF) and lignin sulfonate dispersant TS-3 in a mass ratio of 1:1 were weighed and prepared using the same process as in the examples to obtain the comparative dye product.

[0032] To further illustrate the technical effects of the specific dye monomer compounding system of this invention, a comparative example is provided. The comparative example uses ternary compounding systems composed of vat dye monomers with different structural types. While maintaining consistent dye component ratios and preparation processes, these systems are compared with the vat violet 9, vat green 1, and vat blue 6 compounding systems in the embodiments of this invention to evaluate the impact of different dye monomer combinations on chlorine bleaching resistance, lightfastness, and color stability during storage.

[0033] Table 2 Raw material ratios in each comparative example

[0034] III. Comprehensive Colorfastness Test of Examples and Comparative Examples The vat dyes prepared from the commercial dyes of Examples 1-5 and Comparative Examples 1-5 were used to dye cotton fabrics according to the relevant provisions of GB / T2374-2007. The color fastness of the fabric samples was measured using ISO105-B02, ISO105-N01, ISO105-C06, and ISO105-E04. The test results are shown in Table 3.

[0035] Table 3. Performance comparison of vat dyes prepared in each example and comparative example. Unit: grade.

[0036] As can be seen from Table 3, the overall color fastness of the high chlorine bleach fastness bright blue vat dye composition obtained in the embodiments of the present invention is significantly better than that of the comparative example. In the embodiments of the present invention, the chlorine bleach fastness reaches grade 4-5, with a maximum of grade 5; the light fastness reaches grade 7-8; and the water wash fastness and acid and alkali perspiration fastness both reach grade 4-5 or above, exhibiting excellent overall fastness performance.

[0037] In contrast, although the comparative example also used three vat dye monomers for blending, due to the different types of dye monomers selected, the components failed to achieve the same synergistic effect as the present invention in terms of overall color matching, oxidative stability, and fiber adsorption performance. Therefore, the chlorine bleaching resistance and overall color fastness of the resulting dye compositions were reduced. Specifically, the highest chlorine bleaching fastness achieved in the comparative example was only grade 3-4, with some formulations dropping to grade 2-3, significantly lower than the embodiments of the present invention.

[0038] The above results indicate that by employing a specific combination of dye monomers and optimizing the component ratio, the present invention can effectively improve the stability of the vat blue dye composition to the oxidizing environment, and achieve a synergistic improvement in chlorine bleach resistance, lightfastness and overall color fastness while maintaining the bright blue light.

[0039] IV. Color stability (Da) test during storage (company testing method) Since there is currently no unified national or industry standard for the color change of vat blue dye during storage, this invention uses a color stability testing method established by the company for evaluation during storage. The specific testing steps are as follows: 1. After dyeing the cotton fabric according to GB / T 2374-2007, dry it in a 60℃ forced-air drying oven for 30 minutes to ensure the fabric is fully dry. Then cool it to ambient temperature at room temperature and immediately measure the color parameters of the sample using a spectrophotometer. Use this moment as the color reference (0 h).

[0040] 2. Divide the same piece of dyed fabric into two groups: (1) Sealed storage group: Store in a sealed polyethylene bag to avoid the influence of air and environmental humidity; (2) Normal temperature and humidity storage group: placed in the laboratory at normal temperature and humidity (25±2℃, relative humidity 65±5%) to simulate the actual storage environment of the enterprise.

[0041] 3. The colorimetric parameters of the samples were measured using the same spectrophotometer at storage times of 0.5 h, 1.0 h, 1.5 h, 2.0 h, 5 h and 24 h, and the Da value at each time point relative to the 0 h time point was calculated.

[0042] Where: Da > 0 indicates that the colored light is shifted towards red light; Da < 0 indicates that the colored light is shifted towards green light; the smaller the absolute value of Da, the better the stability of the colored light during storage.

[0043] The test results are shown in Tables 4-7. Table 4. Da values ​​under sealed storage conditions in the examples

[0044] Table 5. Da values ​​under normal temperature and humidity storage conditions in the examples

[0045] Table 6. Da values ​​under comparative sealed storage conditions

[0046] Table 7. Da values ​​under normal temperature and humidity storage conditions for comparative examples

[0047] As shown in Tables 4 to 7, whether in the embodiments or comparative examples of the present invention, under sealed storage conditions, the Da values ​​of each sample remained at a low level and did not change significantly after 24 hours. This indicates that when the influence of air and ambient humidity is isolated, the dyed fabric has good color stability and basically does not undergo significant color drift during storage.

[0048] In contrast, the two dye systems exhibited significant differences under normal temperature and humidity storage conditions. The Da value of the embodiment of this invention changed only slightly with storage time, remaining at a low level after 24 hours, indicating that the dyed fabric has excellent color stability in actual storage environments. However, the Da value of the comparative sample increased continuously with storage time, significantly higher than that of the embodiment of this invention after 24 hours, indicating that the traditional vat blue dye system is more prone to color shift towards red in humid environments, a phenomenon commonly referred to in the industry as "reddening upon contact with water." The main reason for this is that the three dye monomers used in this invention have good structural matching and comprehensive color compensation effects. By optimizing the ratio of the three dye monomers, different components form a synergistic effect in terms of color regulation, oxidation stability, and storage stability, thereby reducing dye structure changes and comprehensive color drift during long-term storage. In contrast, the comparative sample, due to insufficient comprehensive color matching and stability synergy among the dye monomers, is more prone to inter-component interactions under humidity, leading to a color shift towards red.

[0049] Since this invention sets up 5 sets of examples and 5 sets of comparative examples, in order to more intuitively compare the differences in color stability of the two dye systems during the overall storage process, the average value of Da values ​​of the 5 sets of examples and 5 sets of comparative examples at each time point under normal temperature and humidity storage conditions is calculated, and the calculation results are as follows.

[0050] Table 8. Average Da values ​​of Examples 1-5 and Comparative Examples 1-5 under normal temperature and humidity storage conditions.

[0051] Based on the above average values, plot the curves of the average Da versus storage time for the embodiments of the present invention and the comparative examples, as shown below. Figure 1 As shown.

[0052] Depend on Figure 1 It can be seen that the average Da values ​​of both the embodiments of the present invention and the comparative examples gradually increase with the extension of storage time, but the trends of change are significantly different. The average Da value of the embodiments of the present invention remains at a low level, only 0.088 after 24 hours; while the average Da value of the comparative examples increases rapidly, reaching 0.552 after 24 hours, which is about 6.3 times that of the embodiments of the present invention.

[0053] The two curves gradually separated as the storage time increased, indicating that the invention, by using a compound system of three vat dyes—Vacuum Violet 9, Vacuum Green 1, and Vacuum Blue 6—can significantly suppress color drift of dyed fabrics in a humid storage environment, improve color stability during storage, and effectively reduce the "reddening upon contact with water" phenomenon commonly found in the industry.

[0054] Based on the comprehensive color fastness test results in Tables 3 to 7, it can be seen that while maintaining excellent chlorine bleach fastness, water washing fastness, perspiration fastness and light fastness, the present invention further improves the weather resistance and storage stability of dyed fabrics, and has good industrial application value. It can meet the application requirements of high chlorine bleach fastness, high weather resistance and long-term storage stability in high-end textiles and workwear fabrics.

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A composition of a bright blue vat dye with high chlorine bleach fastness, characterized in that, The dye composition consists of the following components: A dye monomer A of chemical formula (1) in a weight percentage of 15-20%; （1） A dye monomer B of chemical formula (2) in a weight percentage of 12-18%; （2） A dye monomer C of chemical formula (3) in a weight percentage of 7-15%; （3） The remainder are dispersants.

2. The high chlorine bleach fastness bright blue vat dye composition as described in claim 1, characterized in that, The dye monomer A has a weight percentage of 16-19%, the dye monomer B has a weight percentage of 13-17%, the dye monomer C has a weight percentage of 8-13%, and the remainder is a dispersant.

3. The high chlorine bleach fastness bright blue vat dye composition as described in claim 1, characterized in that, The dye monomer A has a weight percentage of 17-18%, the dye monomer B has a weight percentage of 14-16%, the dye monomer C has a weight percentage of 9-11%, and the remainder is a dispersant.

4. The high chlorine bleach fastness bright blue vat dye composition as described in claim 1, characterized in that, The total mass of dye monomer A, dye monomer B, and dye monomer C accounts for 40-45% of the weight percentage of the dye composition.

5. The high chlorine bleach fastness bright blue vat dye composition according to any one of claims 1 to 4, characterized in that, The dispersant is one or a mixture of two of sodium lignosulfonate and methylnaphthalenesulfonic acid formaldehyde condensate.

6. A method for preparing a bright blue vat dye composition with high chlorine bleach fastness as described in any one of claims 1 to 4, characterized in that, According to the formula ratio, weigh the filter cake and dispersant of dye monomer A, dye monomer B, and dye monomer C, add them to the pulping pot and mix and pulp. Grind them to the endpoint in a high-efficiency sand mill, filter and spray dry to obtain a bright blue vat dye composition with high chlorine fastness.

7. The method as described in claim 6, characterized in that, The particle size D90 of the slurry is ≤1μm after grinding in a high-efficiency sand mill to the end point.

8. The method as described in claim 6, characterized in that, The spray drying temperature is 130℃.

9. The application of the high chlorine fastness bright blue vat dye composition according to any one of claims 1 to 4 in the dyeing of cellulosic fiber fabrics.

10. A cellulose fiber fabric, characterized in that... The dye is obtained by dyeing with the high chlorine fastness bright blue vat dye composition according to any one of claims 1 to 4.

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