High-dispersity acidic leveling agent and preparation method thereof

Abstract

The invention relates to the field of textile auxiliaries, in particular to a high-dispersity acidic leveling agent and a preparation method thereof. The leveling agent provided by the invention is prepared by compounding the following raw materials in parts by mass: 2.5-15 parts of an anionic dispersant, 30-60 parts of a thixotropic agent, 35-60 parts of a surfactant and 5-10 parts of water, wherein the thixotropic agent is prepared by amidating long-chain fatty acid with more than 10 carbon atoms with hydroxyethyl ethylenediamine in sequence and then carrying out ring-opening addition with ethylene oxide. The high-dispersion acidic leveling agent provided by the invention is simple in preparation process, can be mixed at normal temperature, is suitable for acid dye dyeing systems such as chinlon and wool, and can improve the dye utilization rate and omit the subsequent softening and finishing process.

Description

Technical Field

[0001] This invention relates to the field of textile auxiliaries, and more specifically, to a highly dispersible acidic leveling agent and its preparation method. Background Technology

[0002] Acidic leveling agents are important auxiliaries, mainly used to improve the uniform distribution, retarding, and migration properties of dyes, thereby enhancing dyeing quality and efficiency. Traditional acidic leveling agents typically use fatty alcohol polyoxyethylene ethers as their main component. While they offer some leveling effect, several problems remain in practical applications. For example, insufficient dispersibility can lead to dye aggregation, affecting dyeing uniformity; poor retarding properties may result in excessively rapid dye uptake in low-temperature zones and insufficient uptake in high-temperature zones, ultimately affecting color yield; furthermore, some leveling agents tend to gel at high concentrations and exhibit poor dilution stability, increasing the difficulty of use.

[0003] Furthermore, acid dyeing systems for nylon, wool, and other fibers place stringent demands on the performance of leveling agents. On one hand, the leveling agent must rapidly establish a retarding barrier in the initial dyeing stage to inhibit color variations caused by instantaneous dye uptake. On the other hand, the leveling agent must possess sufficient migration capacity during the high-temperature holding stage to ensure the adsorbed dye is redistributed evenly. Traditional solutions generally employ short-chain fatty acids or their derivatives as hydrophobic building blocks. Their advantages lie in their small molecular size and good water solubility, allowing them to maintain a "non-gelling" flow state under high concentration or low temperature conditions while rapidly diffusing on the fiber surface to form an initial retarding layer. For example, Chinese patent CN104141251B discloses a high-temperature leveling agent for microfiber fabrics, which uses isooctanoic acid, isononanoic acid, or isodecanic acid esterified with polyethylene glycol, achieving excellent processing convenience and basic leveling performance through a short-chain backbone. However, short-chain fatty acid backbones have certain drawbacks in terms of final hand feel. During heat setting of nylon fabrics at 180-200℃, the amorphous regions of the fibers rearrange. Short-chain leveling agents, due to their short carbon chains and weak intermolecular forces, cannot construct a continuous, flexible coating layer on the fiber surface, nor can they counteract the increased rigidity caused by heat setting. As a result, the fabric's coefficient of friction increases, resulting in a stiff and dry feel. Additional softeners must be added for secondary finishing, which not only increases the number of processes and costs but also easily leads to compatibility conflicts with leveling agents, causing problems such as decreased color fastness and color drift.

[0004] Therefore, developing acidic leveling agents that can maintain excellent leveling performance and impart a soft hand feel to fabrics after high-temperature setting has become an urgent technical problem to be solved in the field of textile auxiliaries. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the first aspect of the present invention provides a highly dispersible acidic leveling agent, the raw materials for which are prepared by mass parts include: 2.5-15 parts dispersant, 30-60 parts thixotropic agent, 35-60 parts surfactant, and 5-10 parts water.

[0006] As an example of implementation, the dispersant is an anionic surfactant.

[0007] Furthermore, the anionic surfactant includes one or more of the following: α-benzyl naphthalene sulfonate formaldehyde condensate, sodium lignin sulfonate, sodium methylene bisnaphthalene sulfonate, sodium alkylbenzene sulfonate, or sodium alkyl sulfonate.

[0008] Furthermore, the dispersant is sodium lignosulfonate.

[0009] As an example of implementation, the surfactant is a nonionic surfactant.

[0010] Furthermore, the nonionic surfactant includes fatty alcohol polyoxyethylene ether.

[0011] Furthermore, the fatty alcohol polyoxyethylene ether includes one or more of fatty alcohol polyoxyethylene ether 1802, fatty alcohol polyoxyethylene ether 1815, fatty alcohol polyoxyethylene ether 1820 or fatty alcohol polyoxyethylene ether 1835.

[0012] In this invention, anionic surfactants are selected as dispersants. These surfactants introduce negative charges onto the dye particle surface through sulfonic acid groups, creating charge repulsion and preventing secondary dye aggregation. Nonionic surfactants, such as fatty alcohol polyoxyethylene ethers, provide steric hindrance through long-chain polyoxyethylene segments, further "expanding" the dye micelles and preventing aggregation caused by charge shielding at high temperatures. Anionic dispersants address primary dye aggregation through charge anchoring, while nonionic fatty alcohol polyoxyethylene ethers address secondary aggregation and fiber penetration issues under high temperature and high salt conditions through steric hindrance and interfacial wetting. However, the dosage of dispersants and surfactants needs to be further limited. Excessive dispersant dosage leads to an overabundance of anionic groups, weakening the retarding effect of fatty alcohol polyoxyethylene ethers. Conversely, insufficient dispersant dosage makes it difficult for fatty alcohol polyoxyethylene ethers alone to prevent dye aggregation, resulting in decreased dispersibility and reduced leveling performance of the leveling agent.

[0013] As an implementable example, the method for preparing the thixotropic agent includes:

[0014] S1. Under nitrogen atmosphere, ethylenediamine and inorganic base are mixed and heated to 160-180℃. Then ethylene oxide (EO) is added and reacted for 2-5 hours. After the reaction is completed, the product hydroxyethyl ethylenediamine is collected by vacuum distillation.

[0015] S2. Mix fatty acids and hydroxyethyl ethylenediamine in an acidic environment and react them at 140-180℃ in an acidic environment to obtain the amide intermediate.

[0016] S3. Mix the amide intermediate, EO and catalyst, and react them at 1-5 bar and 80-120°C to obtain the thixotropic agent.

[0017] As an implementable example, in step S1, the mass ratio of ethylenediamine to EO is (100-120):(40-50).

[0018] As an example of implementation, the inorganic base in step S1 includes KOH or NaOH.

[0019] Furthermore, the inorganic base is KOH, and the reaction formula for step S1 is as shown in formula (1):

[0020]

[0021] As an example of implementation, the vacuum distillation is carried out at a temperature of 235-240°C and a pressure of 200-210 kPa.

[0022] As an feasible example, the fatty acid (R-COOH) has more than 10 carbon atoms, and the reaction formula for step S2 is as shown in formula (2):

[0023]

[0024] Furthermore, the fatty acids include one or more of lauric acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, or stearic acid.

[0025] Furthermore, the fatty acid mentioned is oleic acid.

[0026] This invention uses long-chain fatty acids with more than 10 carbon atoms as hydrophobic units. After amidation with hydroxyethyl ethylenediamine, long-chain alkyl groups are introduced at the molecular ends. The resulting amide intermediate chemically bonds with nylon fibers through amide bonds, and utilizes the van der Waals forces between the hydrophobic segments and the fibers to construct a flexible lubricating layer, thereby significantly reducing the coefficient of friction between fibers and giving the fabric a soft and smooth feel. Simultaneously, this hydrophobic segment further combines with the hydrophilic polyether segment formed by subsequent addition of ethylene oxide to form a hydrophobic-hydrophilic block structure, ensuring both gel-free and excellent leveling performance in high-concentration systems, and providing durable wash resistance. This effectively solves the defect of hardening of fabric hand feel after high-temperature setting of traditional acidic leveling agents.

[0027] As an implementable example, the molar ratio of the fatty acid to hydroxyethyl ethylenediamine is 1:

[0028] (1-1.25).

[0029] As an feasible example, in step S3, the molar ratio of the amide intermediate to EO is 1:(10-30), and the reaction formula for step S3 is as shown in formula (3):

[0030]

[0031] Furthermore, in step S3, the molar ratio of the amide intermediate to EO is 1:25.

[0032] This invention limits the molar ratio of amide intermediate to EO to 1:25, which allows for the control of polyether segment length, resulting in a molecule with both moderate hydrophilicity and hydrophobicity. This ensures, on the one hand, that the high-concentration system is gel-free and the dye liquor is uniformly dispersed; on the other hand, it guarantees the full interaction between the amide bond and the nylon hydrogen bond, achieving excellent retarded and migrating dyeing properties. Simultaneously, the 1:25 molar ratio of amide intermediate to EO avoids excessive hydrophilicity and decreased binding strength due to excess EO, and also prevents poor water solubility and reduced leveling properties due to insufficient EO. ​​This results in a stable, highly adaptable thixotropic agent under high-pressure reaction conditions, imparting a soft, smooth, and washable hand feel to the fabric.

[0033] As an example of implementation, the catalyst includes AlMe3-NH4Cl or Me2AlNH2.

[0034] Furthermore, the amount of catalyst used is 0.5-1% of the total molar amount of amide intermediate and EO.

[0035] A second aspect of the present invention provides a method for preparing a highly dispersed acidic leveling agent, comprising:

[0036] According to the mass fraction, mix the dispersant, thixotropic agent, surfactant and water, heat to 30-50℃, and stir at 50-100 rpm for 1-1.5 hours to obtain a highly dispersed acidic leveling agent.

[0037] Beneficial effects

[0038] (I) This invention limits the raw materials to include 2.5-15 parts of dispersant and 35-60 parts of fatty alcohol polyoxyethylene ether. The two work together to ensure that the dye remains nanoscale dispersed under high temperature and high salt conditions, thus solving the problem of color spots caused by dye aggregation in traditional leveling agents.

[0039] (ii) The thixotropic agent and fatty alcohol polyoxyethylene ether compound system in this invention establishes a slow dyeing barrier in the early stage of dyeing, inhibits instantaneous dyeing, and has excellent migration ability, without the need for additional softener.

[0040] (III) In the process of preparing thixotropic agents, this invention designs a long-chain fatty acid amide-polyether block molecular structure, which enables the product to remain transparent and fluid in an aqueous system, avoiding the defects of high-concentration gel and low-temperature thickening of traditional products, and facilitating on-site dilution and automatic feeding.

[0041] (iv) In the process of preparing the thixotropic agent, the present invention selects long-chain fatty acids with more than 10 carbon atoms as raw materials for the amidation reaction. The generated amide bonds anchor the nylon surface to form a flexible lubricating layer, which significantly reduces the friction coefficient between fibers, reduces costs, and avoids compatibility conflicts.

[0042] (v) The leveling agent prepared in this invention reduces ineffective dye deposition and residual color in the foot water through the synergistic effect of leveling and transfer dyeing. The color yield of the dyed sample is better than that of similar products on the market. While ensuring the leveling effect, it improves the dyeing rate and directly reduces the dyeing cost. Detailed Implementation

[0043] Example 1

[0044] The first aspect of this example provides a highly dispersible acidic leveling agent, the raw materials for which are prepared by mass parts are: 2.5 parts dispersant, 45 parts thixotropic agent, 45 parts surfactant, and 7.5 parts water.

[0045] The dispersant is α-benzyl naphthalene sulfonic acid formaldehyde condensate, purchased from Henan Weitixi Chemical Technology Co., Ltd.

[0046] The surfactant mentioned is fatty alcohol polyoxyethylene ether 1802, purchased from Haian Petrochemical Plant Co., Ltd.

[0047] The preparation method of the thixotropic agent is as follows:

[0048] S1. Under nitrogen atmosphere, 112g of ethylenediamine and 0.8g of KOH were mixed, heated to 160℃ and held for 1h; then heated to 180℃ and held for 2h; then, under 0.60MPa pressure, 22.2g of EO was added to each of the two batches and reacted for 3h. After the reaction was completed, the unreacted ethylenediamine was recovered by distillation, and then the product hydroxyethyl ethylenediamine was collected by vacuum distillation at 235℃ and 204.41kPa.

[0049] S2. Oleic acid and hydroxyethyl ethylenediamine are mixed in a molar ratio of 1:1. The mixture is kept at 140°C for 2 hours in an acidic environment with pH 2.5 to carry out the first dehydration. Then the temperature is raised to 180°C and kept for 2 hours to carry out the second dehydration, thus obtaining the amide intermediate.

[0050] S3. Mix the amide intermediate, EO and the catalyst AlMe3-NH4Cl, and react at 80°C for 1 hour under 2 bar pressure. Then, raise the temperature to 100°C and react for 1 hour. Finally, raise the temperature to 120°C and react for 1 hour to obtain the thixotropic agent. The molar ratio of the amide intermediate, EO and AlMe3-NH4Cl is 1:25:0.13.

[0051] The second aspect of this example provides a method for preparing a highly dispersed acidic leveling agent, specifically as follows:

[0052] Based on the mass fraction, water is first added to a stirred tank, followed by dispersant, thixotropic agent and surfactant in sequence. The mixture is heated to 40°C and stirred at 100 rpm for 1.5 hours to obtain a highly dispersed acidic leveling agent.

[0053] Example 2

[0054] The first aspect of this example provides a highly dispersible acidic leveling agent, the raw materials for which are prepared by mass parts are: 2.5 parts dispersant, 45 parts thixotropic agent, 45 parts surfactant, and 7.5 parts water.

[0055] The dispersant is sodium lignosulfonate.

[0056] The surfactant is fatty alcohol polyoxyethylene ether 1802.

[0057] The thixotropic agent described is the same as the thixotropic agent in Example 1.

[0058] The second aspect of this example provides a method for preparing a highly dispersed acidic leveling agent, specifically as follows:

[0059] Based on the mass fraction, water is first added to a stirred tank, followed by dispersant, thixotropic agent and surfactant in sequence. The mixture is heated to 40°C and stirred at 100 rpm for 1.5 hours to obtain a highly dispersed acidic leveling agent.

[0060] Example 3

[0061] The first aspect of this example provides a highly dispersible acidic leveling agent, the raw materials for which are prepared by mass parts are: 2.5 parts dispersant, 45 parts thixotropic agent, 45 parts surfactant, and 7.5 parts water.

[0062] The dispersant is sodium lignosulfonate.

[0063] The surfactant mentioned is fatty alcohol polyoxyethylene ether 1815, purchased from Haian Petrochemical Plant Co., Ltd.

[0064] The thixotropic agent described is the same as the thixotropic agent in Example 1.

[0065] The second aspect of this example provides a method for preparing a highly dispersed acidic leveling agent, specifically as follows:

[0066] Based on the mass fraction, water is first added to a stirred tank, followed by dispersant, thixotropic agent and surfactant in sequence. The mixture is heated to 40°C and stirred at 100 rpm for 1.5 hours to obtain a highly dispersed acidic leveling agent.

[0067] Example 4

[0068] The first aspect of this example provides a highly dispersible acidic leveling agent, the raw materials for which are prepared by mass parts are: 2.5 parts dispersant, 45 parts thixotropic agent, 45 parts surfactant, and 7.5 parts water.

[0069] The dispersant is sodium lignosulfonate.

[0070] The surfactant mentioned is fatty alcohol polyoxyethylene ether 1820, purchased from Haian Petrochemical Plant Co., Ltd.

[0071] The thixotropic agent described is the same as the thixotropic agent in Example 1.

[0072] The second aspect of this example provides a method for preparing a highly dispersed acidic leveling agent, specifically as follows:

[0073] Based on the mass fraction, water is first added to a stirred tank, followed by dispersant, thixotropic agent and surfactant in sequence. The mixture is heated to 40°C and stirred at 100 rpm for 1.5 hours to obtain a highly dispersed acidic leveling agent.

[0074] Example 5

[0075] The first aspect of this example provides a highly dispersed acidic leveling agent, the raw materials for which are prepared by mass parts are: 45 parts thixotropic agent, 45 parts surfactant, and 10 parts water.

[0076] The surfactant is fatty alcohol polyoxyethylene ether 1802.

[0077] The thixotropic agent described is the same as the thixotropic agent in Example 1.

[0078] The second aspect of this example provides a method for preparing a highly dispersed acidic leveling agent, specifically as follows:

[0079] According to the mass fraction, water is first added to the stirred tank, followed by the thixotropic agent and surfactant in sequence. The temperature is raised to 40°C, and the mixture is stirred at 100 rpm for 1.5 hours to obtain a highly dispersed acidic leveling agent.

[0080] Performance Evaluation

[0081] 1. Transmissibility test

[0082] Test method: Colored fabric and undyed fabric of the same specification and weight were sewn together with undyed polyester thread. The product from Examples 1-5 was applied at a rate of 0.5 g / L, acetic acid (50 wt%) at 0.8 g / L, with a liquor ratio of 1:20. The fabric was then dyed at 40°C, with the temperature increased to 98°C at a rate of 1.5°C / min, held for 30 min, and then cooled to 60°C. The fabric was then washed, dried, and ready for testing. After regaining moisture, the K / S values ​​of the colored and white fabrics were tested, and the migration rate was calculated using the following method.

[0083]

[0084] Among them, the higher the migration rate, the better the migration performance.

[0085] 2. Slow-release test

[0086] Test Method: Prepare 10 identical dye solutions using Acid Blue 2037 1.5wt%, the product from Examples 1-5 0.25g / L, and acetic acid (50wt%) 0.8g / L at a liquor ratio of 1:20. Run the solutions at room temperature (25℃) for 10 minutes, then increase the temperature at a rate of 1℃ / min. Run the solutions at 50℃, 60℃, 70℃, 80℃, 90℃, 98℃, 98℃×15min, 98℃×30min, 98℃×45min, and 98℃×60min respectively. Retain the residual water, wash, dry, and rehydrate before mounting the samples. Test the K / S value at different temperatures. The slower the increase in K / S value, the better the slow-dyeing performance. Sort the K / S values ​​from slowest to fastest as follows: very good, good, relatively good, slightly poor, poor, very poor.

[0087] 3. Dispersion test

[0088] Test method: Take 0.5 g / L each of Disperse Ruby S-2GFL and Disperse Brilliant Blue 2BLM, add 0.5 g / L of the product from Examples 1-5 to the working solution at pH=5, heat to 98℃ at a rate of 2℃ / min and run for 30 min, then cool to 60℃ at a rate of 2℃ / min and filter. Dry the filter paper and observe the dye diffusion on the filter paper surface. A high concentration of dye on the filter paper surface indicates poor dispersion performance, and vice versa. Based on a self-made test card, the minimum residue is rated as level 5.

[0089] 4. Hydrogel addition test

[0090] Test method: Weigh 20g of the product from Examples 1-5 into a beaker, add 10g of water and stir. After stirring evenly, observe the state of the solution. If the solution is transparent and fluid, it is non-gelling. If it is viscous and requires heating to become fluid, it is gelling.

[0091] 5. Hand feel test

[0092] Test method: A blind test was conducted by five people using pinching, touching, grasping, and visual inspection to rank the softness and smoothness of the textiles treated with the products in Examples 1-5. The samples were ranked according to their softness, with smaller numbers indicating better feel, i.e., number 1 being the softest sample.

[0093] 6. Dyeing percentage test

[0094] Calculate the dye uptake percentage E according to the formula:

[0095] E = (1 - A1 / A0) × 100% A1 — absorbance of the residual solution after staining;

[0096] A0—Absorbance of the dye solution before dyeing (625nm);

[0097] The results of the above tests are detailed in Table 1.

[0098] Table 1

[0099] leveling agent transmissibility Slow staining Dispersion Percentage of staining (%) Does adding water cause gelation? feel Fatty alcohol polyoxyethylene ether 1815 68.10 better 3 80.75 yes 6 Example 1 67.95 Poor 3-4 85.96 no 4 Example 2 67.78 Slightly worse 4 85.73 no 3 Example 3 70.29 very good 4-5 87.56 no 2 Example 4 68.41 good 4 84.39 no 1 Example 5 65.18 Very bad 3 86.37 no 5

[0100] As can be seen from the experimental results in Table 1, since no dispersant was used in Example 5, the leveling agent prepared had poorer migration, slow dyeing and dispersibility compared with Examples 1-4. Therefore, it can be seen that the appropriate combination of dispersant and surfactant has a significant impact on the performance of leveling agent.

Claims

1. A highly dispersible acidic leveling agent, characterized in that, The raw materials for preparation, by mass parts, include: 2.5-15 parts dispersant, 30-60 parts thixotropic agent, 35-60 parts surfactant, and 5-10 parts water; The dispersant is an anionic surfactant.

2. The highly dispersed acidic leveling agent according to claim 1, characterized in that, The anionic surfactants include one or more of α-benzyl naphthalene sulfonate formaldehyde condensate, sodium lignin sulfonate, sodium methylene bisnaphthalene sulfonate, sodium alkylbenzene sulfonate, or sodium alkyl sulfonate.

3. The highly dispersed acidic leveling agent according to claim 1, characterized in that, The surfactants include one or more of fatty alcohol polyoxyethylene ether 1802, fatty alcohol polyoxyethylene ether 1815, fatty alcohol polyoxyethylene ether 1820 or fatty alcohol polyoxyethylene ether 1835.

4. The highly dispersible acidic leveling agent according to any one of claims 1-3, characterized in that, The method for preparing the thixotropic agent includes: S1. Mix ethylenediamine and inorganic base, heat to 160-180℃, then add ethylene oxide and react for 2-5 hours. After the reaction is complete, collect the product hydroxyethyl ethylenediamine by vacuum distillation. S2. Mix fatty acids and hydroxyethyl ethylenediamine in an acidic environment and react them at 140-180℃ in an acidic environment to obtain the amide intermediate. S3. Mix the amide intermediate, EO and catalyst, and react them at 1-5 bar and 80-120°C to obtain the thixotropic agent.

5. The highly dispersed acidic leveling agent according to claim 4, characterized in that, The fatty acid has more than 10 carbon atoms.

6. The highly dispersed acidic leveling agent according to claim 5, characterized in that, The fatty acids mentioned include one or more of lauric acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, or stearic acid.

7. The highly dispersed acidic leveling agent according to claim 4, characterized in that, The molar ratio of the fatty acid and hydroxyethyl ethylenediamine is 1:(1-1.25).

8. The highly dispersed acidic leveling agent according to claim 4, characterized in that... In step S3, the molar ratio of the amide intermediate to EO is 1:(10-30).

9. The highly dispersed acidic leveling agent according to claim 4, characterized in that, The catalysts include AlMe3-NH4Cl or Me2AlNH2.

10. A method for preparing a highly dispersed acidic leveling agent according to any one of claims 1-9, characterized in that, include: According to the mass fraction, mix the dispersant, thixotropic agent, surfactant and water, heat to 30-50℃, and stir at 50-100 rpm for 1-1.5 hours to obtain a highly dispersed acidic leveling agent.

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