Process for the preparation of alkali resistant liquid disperse dyes by anti-solvent crystallization

Abstract

This invention provides a method for preparing alkali-resistant liquid disperse dyes using an antisolvent crystallization method, comprising the following steps: dissolving a solid alkali-resistant disperse dye in a low-boiling-point solvent, ultrasonically heating to destroy the dye crystal structure, and filtering to obtain a dye solution; dissolving a crystal control agent and a dispersant in a high-boiling-point solvent to obtain an antisolvent; slowly adding the dye solution to the antisolvent, stirring, cooling, and removing the low-boiling-point solvent after the dye crystals have stabilized. This invention is the first to apply the antisolvent method to the preparation of alkali-resistant liquid disperse dyes. Compared with traditional grinding methods, it has lower energy consumption, simpler equipment, and less pollution. The prepared alkali-resistant liquid disperse dyes can have a particle size as low as 130 nm, exhibit good storage stability, improved dyeing depth compared to conventional alkali-resistant liquid disperse dyes, high dye utilization, and dyeing and washing fastness all above grade 4. It also has a lower COD value than conventional dyes of the same strength, is convenient to use, and simplifies the dyeing process.

Description

Technical Field

[0001] This invention relates to the field of disperse dye preparation technology, and more specifically to a method for preparing alkali-resistant liquid disperse dyes without grinding and with low energy consumption. Background Technology

[0002] With technological advancements, a series of benzene, benzothiazole, and benzisothiazole disperse dyes with varying gradients of alkali and oxidation resistance have been obtained by introducing different substituents. A series of alkali-resistant disperse dyes have subsequently been put into research and production. Alkali-resistant disperse dyes possess high resistance to oxygen bleaching and high oxidation resistance, which can shorten process flow and processing time, and improve production efficiency.

[0003] Disperse dyes are mainly stored in powder and liquid states. Traditional powdered solid disperse dyes require a spray drying process, which occupies a large amount of equipment, requires significant investment, consumes a large amount of energy, and has high production costs; in addition, a large amount of dispersant is used. In recent years, with the advancement of automatic batching and energy-saving and emission-reduction technologies in printing and dyeing, as well as in-depth research on the preparation and application technologies of liquid disperse dyes, the advantages of liquid disperse dyes have gradually become apparent: no spray drying is required during preparation; no chemical additives are needed during application, resulting in no dust pollution, and it is convenient to prepare slurries or dye liquors; due to the low amount of auxiliaries, dye migration is less during continuous pad dyeing, and there is less surface floating color and lighter color of dyeing wastewater during high-temperature immersion dyeing, resulting in high dye utilization; and water washing is not required during printing.

[0004] Compared to traditional packaged disperse dyes, the preparation process of liquid disperse dyes eliminates the intermediate spray drying step, saving energy; reduces dust pollution, making the production process more environmentally friendly; and achieves high dye utilization, lowering the cost of dye wastewater treatment. However, current liquid disperse dyes still suffer from problems such as poor grinding efficiency during preparation and large fluctuations in dye particle size during storage or long-distance transportation. There are two main methods for preparing nano-suspensions: a top-down approach, such as high-pressure homogenization or media grinding; and a bottom-up approach, such as antisolvent crystallization. Top-down media grinding is commonly used in the preparation of alkali-resistant liquid disperse dyes, but this method requires a large amount of energy for grinding, has low grinding efficiency, and requires a long processing time. Antisolvent crystallization has the advantages of low energy consumption and a short preparation cycle. Current research mainly focuses on pharmaceutical and pesticide research, aiming to improve the application performance of pharmaceutical and pesticide suspensions. The preparation of liquid alkali-resistant disperse dyes rarely employs the anti-solvent method. This is because some dyes cannot dissolve well in low-boiling-point solvents, making anti-solvent crystallization impossible. Furthermore, some dyes may exhibit better color intensity, color fastness, and dispersibility when prepared by other methods (such as mechanical stirring, high-pressure homogenization, and media grinding). Summary of the Invention

[0005] [Technical Issues]

[0006] Alkali-resistant disperse dyes possess high resistance to oxygen bleaching and oxidation, which can shorten the process flow and processing time, thereby improving production efficiency. The production process of liquid disperse dyes is environmentally friendly, convenient to use, and can improve dyeing performance. The anti-solvent crystallization method has low energy consumption and a short preparation cycle. However, the preparation of liquid alkali-resistant disperse dyes using the anti-crystallization method suffers from poor color strength, color fastness, and dispersibility. Therefore, a method for preparing liquid alkali-resistant disperse dyes using anti-crystallization with excellent color strength, color fastness, and dispersibility is needed.

[0007] [Technical Solution]

[0008] The first objective of this invention is to provide a method for preparing alkali-resistant liquid disperse dyes by anti-solvent crystallization, comprising the steps of:

[0009] (1) Destruction of dye crystals: Dissolve the alkali-resistant disperse dye solid in a low-boiling-point solvent, heat it with ultrasound, and filter to obtain a dye solution;

[0010] (2) Control of dye crystallization particle size: Dissolve crystal control agent and dispersant in high boiling point solvent to obtain antisolvent; slowly add dye solution to antisolvent, stir, cool down, remove low boiling point solvent, and obtain alkali resistant liquid disperse dye.

[0011] In one embodiment of the present invention, in step (1), the alkali-resistant disperse dye solid is an alkali-resistant disperse dye filter cake; the effective content of the alkali-resistant disperse dye filter cake is 0.5-5% w / w, and the solid content is 1-10% w / w.

[0012] The effective content refers to the content of alkali-resistant disperse dye in the alkali-resistant disperse dye filter cake, and the solid content refers to the content of the remaining part of the alkali-resistant disperse dye filter cake after drying.

[0013] In one embodiment of the present invention, in step (1), the concentration of the alkali-resistant disperse dye in the dye solution is 5 to 50 mg / L.

[0014] In one embodiment of the present invention, the alkali-resistant disperse dye is selected from one or more of the following formulas I, II, and III:

[0015]

[0016] In Formula I, R1 is a C1-5 alkyl or alkoxy group;

[0017] In Formula II, R2 is -H, C1-5 alkyl, benzyl, phenethyl, phenylpropyl, p-methylbenzyl, or m-methylbenzyl;

[0018] In Formula III, R3 is -H, a C1-5 alkyl group, or a C1-5 alkoxy group; R4 is a C1-5 alkyl group, benzyl, phenethyl, phenylpropyl, p-methylbenzyl, or m-methylbenzyl.

[0019] In one embodiment of the present invention, the alkali-resistant disperse dye is selected from one or more of I, II, and III;

[0020] In Formula I, R1 is -CH3 or -OCH3;

[0021] In Formula II, R2 is -H, -CH3, benzyl, p-methylbenzyl, or m-methylbenzyl;

[0022] In Formula III, R3 is -H, -CH3, or -OCH3; R4 is -C2H5, benzyl, p-methylbenzyl, or m-methylbenzyl.

[0023] In one embodiment of the present invention, in step (1), the low-boiling-point solvent is one or more of ethanol (EA), acetone (CP), ethyl acetate (EAC), dichloromethane (DCM), and tetrahydrofuran (THF).

[0024] In one embodiment of the present invention, in step (1), the temperature of ultrasonic heating is 25-35°C.

[0025] In one embodiment of the present invention, in step (1), the filtration method is to use a 0.45 μm organic filter membrane to remove impurities and incompletely dissolved components from the dye solution.

[0026] In one embodiment of the present invention, in step (2), the crystal control agent is a naphthalene-based polymer with the following structure:

[0027]

[0028] Wherein, X group is amino, methyl or -H; a, b, c and n are 1 to 100 respectively; R1 is an alkyl group with 1 to 18 carbon atoms; R2 is -H or -CH3.

[0029] In one embodiment of the present invention, in step (2), the dispersant is one or more of sodium lignosulfonate, sodium methylene bis(naphthalene)sulfonate (NNO), sodium methylene bis(naphthalene)sulfonate (MF), fatty alcohol polyoxyethylene ether, and fatty amine polyoxyethylene ether.

[0030] In one embodiment of the present invention, in step (2), the high-boiling-point solvent is one or more of water, liquid paraffin, decamethylcyclopentasiloxane, choline chloride-urea mixture, and betaine-thiourea mixture.

[0031] In one embodiment of the present invention, in step (2), the concentration of the crystal control agent of the antisolvent is 2-50 mg / mL, the concentration of the dispersant is 3-50 mg / mL, and the volume ratio of the dye solution to the antisolvent is 1-10:10.

[0032] In one embodiment of the present invention, in step (2), the cooling is performed by cooling to 2-10°C using an ice bath.

[0033] A second objective of this invention is to provide an alkali-resistant liquid disperse dye prepared by the above method.

[0034] In one embodiment of the present invention, the components of the alkali-resistant liquid disperse dye are: 0.5-50 mg / L of alkali-resistant disperse dye, 1-50 mg / mL of dispersant, 1-50 mg / mL of crystal control agent, and a high-boiling-point solvent.

[0035] A third objective of this invention is to provide applications of the aforementioned alkali-resistant liquid disperse dyes, including dyeing of synthetic fibers and their textiles, printing of synthetic fiber textiles, and preparation of ultrafine disperse dye inks.

[0036] Beneficial effects:

[0037] Compared with existing technologies for preparing alkali-resistant liquid disperse dyes, this invention provides a method for preparing alkali-resistant liquid disperse dyes without resorting to the energy-intensive process of grinding. The advantages are as follows:

[0038] The preparation process does not involve grinding, a high-energy-consuming and high-pollution step, and the required equipment is simple, without the need for large and complex equipment such as high-pressure homogenizers and sand mills.

[0039] Compared with alkali-resistant powder disperse dyes, the prepared alkali-resistant liquid disperse dyes have high storage stability, good leveling properties, good dyeing depth, low COD value of dyeing wastewater, and high dye utilization rate.

[0040] Compared with alkali-resistant powder disperse dyes, the prepared alkali-resistant liquid disperse dyes have smaller particle sizes, with the smallest reaching 130 nm, providing a new approach for the preparation of disperse dye inks.

[0041] The grinding method can enable some alkali-resistant disperse dyes to exhibit better color strength, color fastness and dispersibility, and the alkali-resistant liquid disperse dyes prepared by this invention also have excellent color strength, color fastness and dispersibility. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the stable particle size distribution in Example 1.

[0043] Figure 2 This is a schematic diagram of the particle size and Zeta potential of the alkali-resistant liquid disperse dye in Example 1. Detailed Implementation

[0044] Test methods

[0045] Storage stability: The prepared alkali-resistant liquid disperse dye suspension was stored at room temperature for 30 days, and its particle size and zeta potential were tested at 7 days and 30 days.

[0046] K / S value: The K / S value of the dyed fabric was measured using a Datacolor 800 colorimeter with a D65 light source and a 10° viewing angle. The measurement was performed 4 times at different parts of the fabric and the average value was taken.

[0047] Dye uptake rate: The absorbance of the dye solution before and after dyeing was measured using a UV spectrophotometer. The concentration and dye uptake rate were calculated by plotting a standard curve.

[0048] COD value: The COD value of the residual liquid after dyeing with powder and liquid disperse dyes at the same dyeing concentration was determined using a DGB-401 multi-parameter water quality analyzer and compared with GB / T 18885-2009.

[0049] Wash fastness: The wash fastness of dyed fabrics was determined in accordance with GB / T 3921—2008 "Textiles - Tests for color fastness - Wash fastness".

[0050] Example 1

[0051] An alkali-resistant liquid disperse dye, prepared by the following method:

[0052] (1) Destruction of dye crystals: 50 mg of alkali-resistant disperse dye filter cake (Ⅰ, R1=-CH3) was dissolved in 10 mL of acetone (AC), ultrasonically heated to 30 °C, and filtered through a 0.45 μm organic filter membrane to obtain a dye solution; the effective content of the alkali-resistant disperse dye filter cake was 0.5% w / w, and the solid content was 1% w / w.

[0053] (2) Control of dye crystallization particle size: 25 mg of naphthalene polymer (R1 = -CH3, R2 = -H, X = -NH2, a = 1, b = 1, c = 1, n = 1), 25 mg of sodium methylene bis(naphthalene) sulfonate (NNO) and 25 mg of octadecylamine polyoxyethylene ether 1820 were dissolved in 10 mL of water to obtain an antisolvent; the antisolvent was placed at 4 °C and under magnetic stirring at 800 rpm, 10 mL of dye solution was slowly added to 10 mL of antisolvent, stirred for 4 h, cooled to 4 °C in an ice bath, and the low-boiling-point solvent was removed by rotary evaporation to obtain alkali-resistant liquid disperse dye.

[0054] Dyeing method using alkali-resistant liquid disperse dyes:

[0055] Using a standard fabric cutting machine, a 1.0g polyester plain weave fabric sample is precisely cut out. After high-temperature and high-pressure dyeing, reduction cleaning, and water washing, the dyed fabric is obtained.

[0056] High-temperature and high-pressure dyeing process: Prepare dye solution (5% owf alkali-resistant liquid disperse dye, 3wt% leveling agent concentration of dye solution, liquor ratio 1:50, pH of dye solution = 4.5) → Heat up (rapidly heat up to 80℃ at 4℃ / min, then slowly heat up to 130℃ at 1℃ / min for 1 hour) → Hold at temperature (cool down to 80℃ and hold for 30 minutes)

[0057] Reduction cleaning and water washing: 2g / L sodium hydrosulfite, 4g / L Na2CO3, liquor ratio 1:80, reduction cleaning at 80℃ for 30 minutes to remove surface color. Liquor ratio 1:20, washing with 80℃ hot water and 25℃ cold water for 15 minutes each.

[0058] Example 2

[0059] An alkali-resistant liquid disperse dye, prepared by the following method:

[0060] (1) Destruction of dye crystals: 50 mg of alkali-resistant disperse dye filter cake (Ⅱ, R2=-CH3) was dissolved in 10 mL of acetone (AC), ultrasonically heated to 30 °C, and filtered through a 0.45 μm organic filter membrane to obtain a dye solution; the effective content of the alkali-resistant disperse dye filter cake was 0.5% w / w, and the solid content was 1% w / w.

[0061] (2) Control of dye crystallization particle size: 25 mg of naphthalene polymer (R1 = -CH3, R2 = -H, X = -NH2, a = 1, b = 1, c = 1, n = 1), 25 mg of sodium methylene bis(naphthalene) sulfonate (NNO) and 25 mg of octadecylamine polyoxyethylene ether 1820 were dissolved in 10 mL of water to obtain an antisolvent; the antisolvent was placed at 4 °C and under magnetic stirring at 800 rpm, 10 mL of dye solution was slowly added to 10 mL of antisolvent, stirred for 4 h, cooled to 4 °C in an ice bath, and the low-boiling-point solvent was removed by rotary evaporation to obtain alkali-resistant liquid disperse dye.

[0062] Dyeing method using alkali-resistant liquid disperse dyes:

[0063] Using a standard fabric cutting machine, a 1.0g polyester plain weave fabric sample is precisely cut out. After high-temperature and high-pressure dyeing, reduction cleaning, and water washing, the dyed fabric is obtained.

[0064] High-temperature and high-pressure dyeing process: Prepare dye solution (5% owf alkali-resistant liquid disperse dye, 3wt% leveling agent concentration of dye solution, liquor ratio 1:50, pH of dye solution = 4.5) → Heat up (rapidly heat up to 80℃ at 4℃ / min, then slowly heat up to 130℃ at 1℃ / min for 1 hour) → Hold at temperature (cool down to 80℃ and hold for 30 minutes)

[0065] Reduction cleaning and water washing: 2g / L sodium hydrosulfite, 4g / L Na2CO3, liquor ratio 1:80, reduction cleaning at 80℃ for 30 minutes to remove surface color. Liquor ratio 1:20, washing with 80℃ hot water and 25℃ cold water for 15 minutes each.

[0066] Example 3

[0067] An alkali-resistant liquid disperse dye, prepared by the following method:

[0068] (1) Destruction of dye crystals: 50 mg of alkali-resistant disperse dye filter cake (Ⅲ, R3=-CH3) was dissolved in 10 mL of acetone (AC), ultrasonically heated to 30 °C, and filtered through a 0.45 μm organic filter membrane to obtain a dye solution; the effective content of the alkali-resistant disperse dye filter cake was 0.5% w / w, and the solid content was 1% w / w.

[0069] (2) Control of dye crystallization particle size: 25 mg of naphthalene polymer (R1 = -CH3, R2 = -H, X = -NH2, a = 1, b = 1, c = 1, n = 1), 25 mg of sodium methylene bis(naphthalene) sulfonate (NNO) and 25 mg of octadecylamine polyoxyethylene ether 1820 were dissolved in 10 mL of water to obtain an antisolvent; the antisolvent was placed at 4 °C and under magnetic stirring at 800 rpm, 10 mL of dye solution was slowly added to 10 mL of antisolvent, stirred for 4 h, cooled to 4 °C in an ice bath, and the low-boiling-point solvent was removed by rotary evaporation to obtain alkali-resistant liquid disperse dye.

[0070] Dyeing method using alkali-resistant liquid disperse dyes:

[0071] Using a standard fabric cutting machine, a 1.0g polyester plain weave fabric sample is precisely cut out. After high-temperature and high-pressure dyeing, reduction cleaning, and water washing, the dyed fabric is obtained.

[0072] High-temperature and high-pressure dyeing process: Prepare dye solution (5% owf alkali-resistant liquid disperse dye, 3wt% leveling agent concentration of dye solution, liquor ratio 1:50, pH of dye solution = 4.5) → Heat up (rapidly heat up to 80℃ at 4℃ / min, then slowly heat up to 130℃ at 1℃ / min for 1 hour) → Hold at temperature (cool down to 80℃ and hold for 30 minutes)

[0073] Reduction cleaning and water washing: 2g / L sodium hydrosulfite, 4g / L Na2CO3, liquor ratio 1:80, reduction cleaning at 80℃ for 30 minutes to remove surface color. Liquor ratio 1:20, washing with 80℃ hot water and 25℃ cold water for 15 minutes each.

[0074] Example 4

[0075] An alkali-resistant liquid disperse dye, prepared by the following method:

[0076] (1) Destruction of dye crystals: 50 mg of alkali-resistant disperse dye filter cake (Ⅰ, R1=-CH3) was dissolved in 10 mL of dichloromethane (DCM), ultrasonically heated to 30 °C, and filtered through a 0.45 μm organic filter membrane to obtain a dye solution; the effective content of the alkali-resistant disperse dye filter cake was 0.5% w / w, and the solid content was 1% w / w.

[0077] (2) Control of dye crystallization particle size: 25 mg of naphthalene polymer (R1 = -CH3, R2 = -H, X = -NH2, a = 1, b = 1, c = 1, n = 1), 25 mg of sodium methylene bis(naphthalene) sulfonate (NNO) and 25 mg of octadecylamine polyoxyethylene ether 1820 were dissolved in 10 mL of water to obtain an antisolvent; the antisolvent was placed at 4 °C and under magnetic stirring at 800 rpm, 10 mL of dye solution was slowly added to 10 mL of antisolvent, stirred for 4 h, cooled to 4 °C in an ice bath, and the low-boiling-point solvent was removed by rotary evaporation to obtain alkali-resistant liquid disperse dye.

[0078] Dyeing method using alkali-resistant liquid disperse dyes:

[0079] Using a standard fabric cutting machine, a 1.0g polyester plain weave fabric sample is precisely cut out. After high-temperature and high-pressure dyeing, reduction cleaning, and water washing, the dyed fabric is obtained.

[0080] High-temperature and high-pressure dyeing process: Prepare dye solution (5% owf alkali-resistant liquid disperse dye, 3wt% leveling agent concentration of dye solution, liquor ratio 1:50, pH of dye solution = 4.5) → Heat up (rapidly heat up to 80℃ at 4℃ / min, then slowly heat up to 130℃ at 1℃ / min for 1 hour) → Hold at temperature (cool down to 80℃ and hold for 30 minutes)

[0081] Reduction cleaning and water washing: 2g / L sodium hydrosulfite, 4g / L Na2CO3, liquor ratio 1:80, reduction cleaning at 80℃ for 30 minutes to remove surface color. Liquor ratio 1:20, washing with 80℃ hot water and 25℃ cold water for 15 minutes each.

[0082] Example 5

[0083] An alkali-resistant liquid disperse dye, prepared by the following method:

[0084] (1) Destruction of dye crystals: 50 mg of alkali-resistant disperse dye filter cake (Ⅰ, R1=-OCH3) was dissolved in 10 mL of acetone (AC), ultrasonically heated to 30 °C, and filtered through a 0.45 μm organic filter membrane to obtain a dye solution; the effective content of the alkali-resistant disperse dye filter cake was 0.5% w / w, and the solid content was 1% w / w.

[0085] (2) Control of dye crystallization particle size: 25 mg of naphthalene polymer (R1 = -CH3, R2 = -H, X = -NH2, a = 1, b = 1, c = 1, n = 1), 25 mg of sodium methylene bis(naphthalene) sulfonate (NNO) and 25 mg of octadecylamine polyoxyethylene ether 1820 were dissolved in 10 mL of water to obtain an antisolvent; the antisolvent was placed at 4 °C and under magnetic stirring at 800 rpm, 10 mL of dye solution was slowly added to 10 mL of antisolvent, stirred for 4 h, cooled to 4 °C in an ice bath, and the low-boiling-point solvent was removed by rotary evaporation to obtain alkali-resistant liquid disperse dye.

[0086] Dyeing method using alkali-resistant liquid disperse dyes:

[0087] Using a standard fabric cutting machine, a 1.0g polyester plain weave fabric sample is precisely cut out. After high-temperature and high-pressure dyeing, reduction cleaning, and water washing, the dyed fabric is obtained.

[0088] High-temperature and high-pressure dyeing process: Prepare dye solution (5% owf alkali-resistant liquid disperse dye, 3wt% leveling agent concentration of dye solution, liquor ratio 1:50, pH of dye solution = 4.5) → Heat up (rapidly heat up to 80℃ at 4℃ / min, then slowly heat up to 130℃ at 1℃ / min for 1 hour) → Hold at temperature (cool down to 80℃ and hold for 30 minutes)

[0089] Reduction cleaning and water washing: 2g / L sodium hydrosulfite, 4g / L Na2CO3, liquor ratio 1:80, reduction cleaning at 80℃ for 30 minutes to remove surface color. Liquor ratio 1:20, washing with 80℃ hot water and 25℃ cold water for 15 minutes each.

[0090] The particle size, Zeta potential, K / S value, dyeing rate, COD value, and washing fastness of the alkali-resistant liquid disperse dyes prepared in the examples are shown in Table 1.

[0091] Table 1

[0092]

[0093]

[0094] The results show that this invention can prepare alkali-resistant liquid disperse dyes with small particle size and good storage stability. In the examples, the washing fastness of the dyeing products was all above grade 4, the dyeing depth was improved by 40% compared to conventional alkali-resistant liquid disperse dyes, and the COD value was reduced by 30% compared to powder dyes of the same strength. Furthermore, due to its alkali resistance, the dyeing process can be shortened, reducing energy consumption. The alkali-resistant liquid disperse dyes prepared by this method are easy to use and have good application prospects, providing a new method for optimizing the preparation process of alkali-resistant liquid disperse dyes.

[0095] Comparative Example 1

[0096] An alkali-resistant disperse dye solution is prepared by the following method:

[0097] The difference from Example 1 is that the low-boiling solvent is acetonitrile.

[0098] The filter cake has low solubility in acetonitrile and tends to aggregate when crystallized using antisolvents, resulting in low solvent utilization. Therefore, acetonitrile cannot be used as a solvent for the preparation of alkali-resistant liquid disperse dyes by antisolvent crystallization.

[0099] Comparative Example 2

[0100] An alkali-resistant disperse dye solution is prepared by the following method:

[0101] The difference from Example 1 is that the low-boiling solvent is dimethyl sulfoxide.

[0102] Dyeing method using alkali-resistant disperse dye solutions:

[0103] The difference from Example 1 is that in the high temperature and high pressure dyeing process, the amount of alkali-resistant disperse dye solution used in the dyeing solution is 1% owf.

[0104] Dyes have high solubility in dimethyl sulfoxide, but dimethyl sulfoxide has a high boiling point and cannot be removed by rotary evaporation. It will remain in the dye solution, causing difficulties in subsequent dyeing. Therefore, it cannot be used as a solvent for preparing alkali-resistant liquid disperse dyes by anti-solvent crystallization.

[0105] Comparative Example 3

[0106] An alkali-resistant disperse dye solution is prepared by the following method:

[0107] The difference from Example 1 is that the low-boiling solvent is chloroform.

[0108] Chloroform, as an antisolvent, is immiscible with water and will separate into layers when mixed. Therefore, it cannot be used as an antisolvent in the preparation of alkali-resistant liquid disperse dyes and will be unsuitable for dyeing.

[0109] Comparative Example 4

[0110] An alkali-resistant disperse dye solution is prepared by the following method:

[0111] The difference from Example 1 is that sorbitol monooleate is used as a dispersant.

[0112] Dyeing method using alkali-resistant disperse dye solutions:

[0113] The difference from Example 1 is that in the high temperature and high pressure dyeing process, the amount of alkali-resistant disperse dye solution used in the dyeing solution is 1% owf.

[0114] The prepared alkali-resistant liquid disperse dye solution had a particle size of 850.13 nm, but exhibited poor dispersibility, poor stability, and poor leveling properties.

[0115] Comparative Example 5

[0116] An alkali-resistant disperse dye solution is prepared by the following method:

[0117] The difference from Example 1 is that polyvinylpyrrolidone is used as the dispersant.

[0118] Dyeing method using alkali-resistant disperse dye solutions:

[0119] Same as Example 1.

[0120] The prepared liquid disperse dye solution had an initial particle size of 578.65 nm, poor stability, poor leveling properties, and could not be used for dyeing.

[0121] Comparative Example 6

[0122] An alkali-resistant disperse dye solution is prepared by the following method:

[0123] The difference from Example 1 is that sodium methylene bis(naphthalene) sulfonate (NNO) is replaced with sodium dodecylbenzene sulfonate.

[0124] Dyeing method using alkali-resistant disperse dye solutions:

[0125] Same as Example 1.

[0126] The difference from Example 1 is that in the high temperature and high pressure dyeing process, the amount of alkali-resistant disperse dye solution used in the dyeing solution is 2% owf.

[0127] The prepared alkali-resistant disperse dye solution had a particle size of 523.98 nm, but exhibited poor leveling properties and stability.

[0128] Comparative Example 7

[0129] An alkali-resistant liquid disperse dye solution is prepared by the following method:

[0130] The difference from Example 1 is that the alkali-resistant disperse dye used has the following structure:

[0131]

[0132] The dye filter cake has very low solubility in acetone, and dye aggregation easily occurs when the dye solution is mixed with a high-boiling-point antisolvent. This type of alkali-resistant disperse dye filter cake cannot be used to prepare alkali-resistant liquid disperse dyes by antisolvent method.

[0133] The particle size, Zeta potential, K / S value, dyeing rate, COD value, and washing fastness of the alkali-resistant disperse dye solutions prepared in the comparative example are shown in Table 2.

[0134] Table 2

[0135]

[0136]

[0137] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing alkali-resistant liquid disperse dyes by anti-solvent crystallization, characterized in that, Including the following steps: (1) Destruction of dye crystals: Dissolve the alkali-resistant disperse dye solid in a low-boiling-point solvent, heat it with ultrasound, and filter to obtain a dye solution; The alkali-resistant disperse dye is selected from one or more of the following formulas I, II, and III: In Formula I, R1 is a C1~5 alkyl or alkoxy group; In Formula II, R2 is -H, C1~5 alkyl, benzyl, phenethyl, phenylpropyl, p-methylbenzyl or m-methylbenzyl; In Formula III, R3 is -H, a C1-5 alkyl group, or a C1-5 alkoxy group; R4 is a C1-5 alkyl group, benzyl, phenethyl, phenylpropyl, p-methylbenzyl, or m-methylbenzyl. Low-boiling-point solvents include acetone and dichloromethane; (2) Control of dye crystallization particle size: Dissolve crystal control agent and dispersant in water to obtain antisolvent; add dye solution to antisolvent, stir, cool down, remove low boiling point solvent, and obtain alkali resistant liquid disperse dye; the dispersant is sodium methylene bisnaphthalene sulfonate and octadecylamine polyoxyethylene ether. The crystal control agent is a naphthalene-based polymer with the following structure: Wherein, X group is amino; a, b, c, and n are 1; R1 is -CH3; and R2 is -H.

2. The method according to claim 1, characterized in that, In step (1), the concentration of alkali-resistant disperse dye in the dye solution is 5~50 mg / L; the ultrasonic heating temperature is 25~35℃.

3. The method according to claim 1, characterized in that, In step (2), the concentration of the antisolvent crystal control agent is 2-50 mg / mL, and the concentration of the dispersant is 3-50 mg / mL; the volume ratio of the dye solution to the antisolvent is 1-10:10; and the cooling is done by cooling to 2-10℃ in an ice bath.

4. An alkali-resistant liquid disperse dye prepared by the method according to any one of claims 1-3.

5. The application of the alkali-resistant liquid disperse dye according to claim 4 includes dyeing of synthetic fibers and their textiles, printing of synthetic fiber textiles, and preparation of ultrafine disperse dye inks.

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