Dyeing method of polyester fabric

Abstract

The invention discloses a polyester fabric dyeing method, and belongs to the technical field of textile dyeing, the polyester fabric dyeing method comprises the following steps: alkali decrement treatment, preparation of a modified polyester fabric, preparation of a dyeing assistant, and dyeing; the preparation of the modified polyester fabric comprises the following steps: pretreating and modifying the fabric; according to the dyeing method of the polyester fabric, the dyeing difficulty of the polyester can be reduced, the dyeing temperature can be reduced, the polyester fabric can be dyed at the temperature of 60-65 DEG C, and the dyeing energy consumption is reduced; according to the present invention, the dyeing performance of the polyester can be improved, the dyeing percentage of the dye is 98.73-99.14%, the apparent color depth value of the dyed fabric is 20.421-20.655, the color fastness to rubbing is (4-5)-5 level, and the color fastness to soaping is 4-(4-5) level.

Description

Technical Field

[0001] The present invention belongs to the technical field of textile dyeing, and particularly relates to a dyeing method for polyester fabrics. Background Art

[0002] Polyester is a synthetic fiber made by chemical polycondensation of organic dibasic acids and diols. It has excellent wrinkle resistance and shape retention, high strength and elastic recovery ability, and also has characteristics such as abrasion resistance and non-sticking hair. Clothes made of polyester fabrics are not easy to wrinkle during wearing, can maintain the original shape of the clothes, are durable, and are easy to keep clean.

[0003] However, since polyester is a fiber with strong hydrophobicity, it lacks reactive groups in its molecular structure that can interact with dye molecules like cellulose molecules and protein molecules. Moreover, its molecular arrangement is tight and its crystallinity is high. Under normal pressure without suitable auxiliaries, it is very difficult to dye polyester fibers. The traditional high-temperature and high-pressure dyeing method has high requirements for dyeing equipment and large energy consumption, with low dye uptake rate and poor color fastness, which does not conform to the concept of green environmental protection, energy conservation and emission reduction.

[0004] To improve the dyeing performance of polyester, CN106835739A discloses a low-temperature dyeing method for polyester fabrics. This method first pretreats the polyester fabrics with low-temperature plasma, and then uses 2,6-dihydroxyterephthalic acid as a carrier for carrier dyeing. During the dyeing process, a low-temperature dyeing auxiliary is added to increase the solubility of disperse dyes, promote the adsorption of disperse dyes on the fabric surface, and improve the dyeing performance of polyester. However, the dyeing temperature used in this method is 100~105°C, which is lower than the traditional dyeing temperature of 120~140°C, but the dyeing temperature is still relatively high, and true energy conservation has not been achieved. Moreover, if the dyeing temperature is reduced in this method, the dyeing performance of polyester will drop significantly.

[0005] CN105113286A discloses a dyeing and finishing process for high-color-fastness and high-flame-retardant polyester fabrics, including pretreatment, pre-setting, modification treatment, dyeing, soaping, color fixation, post-finishing, drying, setting, calendering, and winding. Before the dyeing process, the fiber fabric is modified with 2,3-epoxypropyltrimethylammonium chloride to modify the performance of the polyester fabric to increase its color uptake rate and reduce the difficulty of subsequent dyeing steps. However, the surface of polyester is relatively smooth, lacking sufficient surface roughness, with a tight molecular chain structure and a lack of hydrophilic structures between molecules. Directly using 2,3-epoxypropyltrimethylammonium chloride to modify the fiber is difficult to establish chemical bonding with the fiber surface, and the fiber performance modification effect is limited, with little effect on improving the color uptake rate of the fabric and reducing the dyeing difficulty. Summary of the Invention

[0006] In view of the deficiencies of the existing technology, the present invention provides a dyeing method for polyester fabrics, which reduces the difficulty of polyester dyeing, reduces the dyeing temperature, reduces energy consumption, and improves the dye uptake percentage, the apparent color depth value of the dyed fabric, and the color fastness.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A dyeing method for polyester fabrics, comprising the following steps: alkali weight reduction treatment, preparation of modified polyester fabrics, preparation of a dyeing assistant, and dyeing.

[0008] The method of the alkali weight reduction treatment is to dissolve an accelerator and a dispersant in a sodium hydroxide solution to prepare an alkali treatment solution, immerse the polyester fabric in the alkali treatment solution, impregnate it at 80-90 °C for 30-40 min, and then wash, neutralize, and dry it thoroughly to obtain an alkali weight reduction treated polyester fabric; The concentration of the sodium hydroxide solution is 10-20 g / L; The accelerator is accelerator 1227 or accelerator Q-12; The dispersant is PA-9 dispersant; The concentration of the accelerator in the alkali treatment solution is 0.5-1 g / L; The concentration of the dispersant in the alkali treatment solution is 1-2 g / L; The mass ratio of the polyester fabric to the alkali treatment solution is 1:20-25.

[0009] The preparation of the modified polyester fabric includes the following steps: fabric pretreatment, modification; The method of the fabric pretreatment is to immerse the alkali weight reduction treated polyester fabric in a diethylenetriamine aqueous solution, soak it at 30-35 °C for 15-20 minutes, roll it to make the fabric wet weight 200% ± 20%, heat it at 160-170 °C for 10-15 min, wash it with water and dry it to obtain a pretreated polyester fabric; The concentration of diethylenetriamine in the diethylenetriamine aqueous solution is 1-1.5 wt%; The mass ratio of the alkali weight reduction treated polyester fabric to the diethylenetriamine aqueous solution is 1:20-40.

[0010] The method of the modification is to immerse the pretreated polyester fabric in modification liquid A, soak it at 10-15 °C for 4-6 minutes, roll it to make the polyester fabric wet weight 200% ± 20%, heat it at 40-45 °C for 8-10 min, wash it with water 3-5 times, roll it to obtain a wet fabric with a wet weight of 180% ± 10%, then immerse the wet fabric in modification liquid B, soak it at 25-30 °C for 8-10 minutes, roll it to make the polyester fabric wet weight 200% ± 20%, heat it at 50-60 °C for 20-25 min, take it out, wash it with water and dry it to obtain a modified polyester fabric; The preparation method of the modified liquid A is as follows: dissolve glycidyl decyldimethylammonium chloride in water, adjust the pH to 8.5 - 9.5, and the mass ratio of water to glycidyl decyldimethylammonium chloride is 100:0.8 - 1; The preparation method of the modified liquid B is as follows: dissolve carboxymethyl chitin, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in water, and adjust the pH to 4 - 6; In the modified liquid B, the mass ratio of water, carboxymethyl chitin, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is 100:0.8 - 1.2:0.9 - 1.1:0.5 - 0.7; The mass ratio of the pretreated polyester fabric to the modified liquid A is 1:30 - 40; The mass ratio of the wet fabric to the modified liquid B is 2:70 - 80.

[0011] The preparation method of glycidyl decyldimethylammonium chloride is as follows: mix decyldimethylamine with absolute ethanol, under a nitrogen atmosphere, raise the temperature to 50 - 55 °C, dropwise add an ethanol solution of epichlorohydrin. After the addition is complete, maintain the temperature and react for 5 - 7 h. After the reaction is completed, evaporate the solvent, wash the product with ether 3 - 5 times, and obtain glycidyl decyldimethylammonium chloride after vacuum drying; The mass ratio of decyldimethylamine, absolute ethanol, and the ethanol solution of epichlorohydrin is 10:4 - 8:8 - 12; The concentration of epichlorohydrin in the ethanol solution of epichlorohydrin is 40 - 50 wt%.

[0012] The method for preparing the dyeing assistant is as follows: uniformly mix fatty acid polyoxyethylene ester, fatty alcohol polyoxyethylene ether and n-butanol to prepare an emulsifier; mix diethylene glycol dibenzoate and N-methylphthalimide with the emulsifier to prepare the dyeing assistant; The HLB value of the fatty acid polyoxyethylene ester is 11.8 - 12.9; The HLB value of the fatty alcohol polyoxyethylene ether is 5.4 - 6.5.

[0013] In the emulsifier, the mass ratio of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester and n-butanol is 20:6 - 8:1 - 2; In the dyeing assistant, the mass ratio of diethylene glycol dibenzoate, N-methylphthalimide and the emulsifier is 100:20 - 30:10 - 15.

[0014] The above dyeing method is as follows: Heat the mordant to 50 - 60°C, then add it to water at 50 - 60°C and stir evenly to obtain a mordant emulsion; Disperse the disperse dye with warm water at 40 - 50°C first to prepare a dye solution. Under stirring, add a pH buffer solution and the mordant emulsion in sequence to obtain the disperse dye; Then raise the temperature of the disperse dye to 40 - 45°C, add the modified polyester fabric, raise the temperature to 60 - 65°C, keep it warm for 50 - 60 min, take out the fabric, wash it with water and dry it to obtain a dyed polyester fabric; The pH buffer solution is acetic acid; In the mordant emulsion, the mass ratio of the mordant to water is 1:45 - 50; In the disperse dye, the mass ratio of the disperse dye, warm water, pH buffer solution, and mordant emulsion is 1:10 - 12:2 - 5:50 - 80; The mass ratio of the modified polyester fabric to the disperse dye is 1:15 - 20.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The dyeing method of the polyester fabric of the present invention can reduce the dyeing difficulty of polyester, lower the dyeing temperature, enable the polyester fabric to be dyed at a temperature of 60 - 65°C, and reduce the dyeing energy consumption; (2) The dyeing method of the polyester fabric of the present invention can improve the dyeing performance of polyester. The dye uptake percentage is 98.73 - 99.14%, the apparent color depth value of the dyed fabric is 20.421 - 20.655, the rubbing fastness is (4 - 5) - 5 grades, and the soaping fastness is 4 - (4 - 5) grades. Specific Embodiments

[0016] In order to have a clearer understanding of the technical features, purposes, and effects of the present invention, the specific embodiments of the present invention are described below.

[0017] Example 1 A dyeing method for polyester fabric includes the following steps: alkali weight reduction treatment, preparation of modified polyester fabric, preparation of mordant, and dyeing.

[0018] (1) Alkali weight reduction treatment Dissolve accelerator 1227 and PA - 9 dispersant in a sodium hydroxide solution of 10 g / L to prepare an alkali treatment solution, so that the concentration of the accelerator in the alkali treatment solution is 0.5 g / L and the concentration of the dispersant is 1 g / L. Immerse the polyester fabric in the alkali treatment solution, soak it at 80°C for 40 min, then wash it thoroughly with water, neutralize it, and dry it to obtain an alkali weight reduction treated polyester fabric; The mass ratio of the polyester fabric to the alkali treatment solution is 1:20.

[0019] (2)Preparation of modified polyester fabric A. Pretreatment of Fabric Soak the alkali-deweighted polyester fabric in an aqueous solution of diethylenetriamine with a concentration of 1 wt%, soak it at 30 °C for 20 minutes, and after rolling, the wet weight of the fabric is 180%. Heat it at 160 °C for 15 min, wash it with water and dry it to obtain the pretreated polyester fabric; The mass ratio of the alkali-deweighted polyester fabric to the aqueous solution of diethylenetriamine is 1:20.

[0020] B. Modification Soak the pretreated polyester fabric in Modifying Solution A, soak it at 10 °C for 6 minutes, and after rolling, the wet weight of the polyester fabric is 180%. Heat it at 40 °C for 10 min, wash it with water 3 times, and roll it to obtain a wet fabric with a wet weight of 170%. Then immerse the wet fabric in Modifying Solution B, soak it at 25 °C for 10 minutes, and after rolling, the wet weight of the polyester fabric is 180%. Heat it at 50 °C for 25 min, take it out, wash it with water and dry it to obtain the modified polyester fabric; The preparation method of the Modifying Solution A is to dissolve glycidyl decyldimethylammonium chloride in water, adjust the pH to 8.5, and the mass ratio of water to glycidyl decyldimethylammonium chloride is 100:0.8; The preparation method of the Modifying Solution B is to dissolve carboxymethyl chitin, ethyl dimethylaminopropyl carbodiimide and N-hydroxysuccinimide in water, adjust the pH to 4, and the mass ratio of water, carboxymethyl chitin, ethyl dimethylaminopropyl carbodiimide and N-hydroxysuccinimide is 100:0.8:0.9:0.5; The mass ratio of the pretreated polyester fabric to the Modifying Solution A is 1:30; The mass ratio of the wet fabric to the Modifying Solution B is 2:70.

[0021] The preparation method of the glycidyl decyldimethylammonium chloride is to mix decyldimethyl tertiary amine with absolute ethanol, under a nitrogen atmosphere, raise the temperature to 50 °C, and dropwise add an ethanol solution of epichlorohydrin with a concentration of 40 wt%. After the dropping is completed, maintain the temperature of 50 °C and react for 7 h. After the reaction is completed, evaporate the solvent, wash the product 3 times with ether, and vacuum dry it to obtain glycidyl decyldimethylammonium chloride; The mass ratio of the decyldimethyl tertiary amine, absolute ethanol and the ethanol solution of epichlorohydrin is 10:4:8.

[0022] (3) Preparation of Dyeing Auxiliary Mix fatty acid polyoxyethylene ester, fatty alcohol polyoxyethylene ether and n-butanol evenly to prepare an emulsifier; mix diethylene glycol dibenzoate, N-methylphthalimide with the emulsifier to prepare a dyeing auxiliary; The HLB value of the fatty acid polyoxyethylene ester is 11.8; The HLB value of the fatty alcohol polyoxyethylene ether is 5.4; The mass ratio of the fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester and n-butanol in the emulsifier is 20:6:1; The mass ratio of the dyeing assistant, diethylene glycol dibenzoate, N-methyl phthalimide and emulsifier is 100:20:10.

[0023] (4) Dyeing Heat the dyeing assistant to 50 °C, and then add it to water at 50 °C and stir evenly to obtain a dyeing assistant emulsion; disperse the disperse dye Disperse Black ECT with warm water at 40 °C first and prepare a dyeing solution. Under stirring, add acetic acid and the dyeing assistant emulsion in sequence to obtain a disperse dye; then take the disperse dye and heat it up to 40 °C, add the modified polyester fabric, heat it up to 60 °C, keep it warm for 60 minutes, take out the fabric, wash it with water and dry it to obtain a dyed polyester fabric; The mass ratio of the dyeing assistant and water in the dyeing assistant emulsion is 1:45; The mass ratio of the disperse dye, warm water, pH buffer solution and dyeing assistant emulsion in the disperse dye is 1:10:2:50; The mass ratio of the modified polyester fabric and the disperse dye is 1:15.

[0024] Example 2 A method for dyeing a polyester fabric, comprising the following steps: alkali weight reduction treatment, preparation of a modified polyester fabric, preparation of a dyeing assistant, and dyeing.

[0025] (1) Alkali weight reduction treatment Dissolve the accelerator 1227 and the PA-9 dispersant in a sodium hydroxide solution of 15 g / L to prepare an alkali treatment solution, so that the concentration of the accelerator in the alkali treatment solution is 0.7 g / L and the concentration of the dispersant is 1.5 g / L. Immerse the polyester fabric in the alkali treatment solution, impregnate it at 85 °C for 35 minutes, and then wash it thoroughly with water, neutralize it and dry it to obtain an alkali weight reduction treated polyester fabric; The mass ratio of the polyester fabric to the alkali treatment solution is 1:22.

[0026] (2) Preparation of a modified polyester fabric A. Fabric pretreatment Immerse the alkali weight reduction treated polyester fabric in a 1 wt% aqueous solution of diethylenetriamine, soak it at 32 °C for 17 minutes, roll it to make the wet weight of the fabric 200%, heat it at 165 °C for 12 minutes, wash it with water and dry it to obtain a pretreated polyester fabric; The mass ratio of the alkali weight reduction treated polyester fabric to the diethylenetriamine aqueous solution is 1:30.

[0027] B. Modification The pretreated polyester fabric is immersed in modifier A at 12 °C for 5 minutes. After rolling, the wet weight of the polyester fabric is 200%. It is heated at 42 °C for 9 minutes, washed with water 4 times, and rolled to obtain a wet fabric with a wet weight of 180%. Then the wet fabric is immersed in modifier B at 27 °C for 9 minutes. After rolling, the wet weight of the polyester fabric is 200%. It is heated at 55 °C for 22 minutes, taken out, washed with water, and dried to obtain the modified polyester fabric; The preparation method of the modifier A is as follows: dissolve glycidyl decyldimethylammonium chloride in water, adjust the pH to 9, and the mass ratio of water to glycidyl decyldimethylammonium chloride is 100:0.9; The preparation method of the modifier B is as follows: dissolve carboxymethyl chitin, N-ethyl-N,N-dimethylaminopropyl carbodiimide and N-hydroxysuccinimide in water, adjust the pH to 5, and the mass ratio of water, carboxymethyl chitin, N-ethyl-N,N-dimethylaminopropyl carbodiimide and N-hydroxysuccinimide is 100:1:1:0.6; The mass ratio of the pretreated polyester fabric to the modifier A is 1:35; The mass ratio of the wet fabric to the modifier B is 2:75.

[0028] The preparation method of the glycidyl decyldimethylammonium chloride is as follows: mix decyldimethylamine with absolute ethanol, raise the temperature to 52 °C under a nitrogen atmosphere, dropwise add an ethanol solution of epichlorohydrin with a concentration of 45 wt%. After the dropping is completed, maintain the temperature of 52 °C and react for 6 h. After the reaction is completed, evaporate the solvent, wash the product 4 times with ether, and obtain glycidyl decyldimethylammonium chloride after vacuum drying; The mass ratio of the decyldimethylamine, absolute ethanol, and the ethanol solution of epichlorohydrin is 10:6:10.

[0029] (3)Prepare the dyeing assistant Mix fatty acid polyoxyethylene ester, fatty alcohol polyoxyethylene ether and n-butanol evenly to prepare an emulsifier; mix diethylene glycol dibenzoate, N-methylphthalimide with the emulsifier to prepare the dyeing assistant; The HLB value of the fatty acid polyoxyethylene ester is 12.6; The HLB value of the fatty alcohol polyoxyethylene ether is 6.1; The mass ratio of the fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester and n-butanol in the emulsifier is 20:7:1.5; The mass ratio of diethylene glycol dibenzoate, N-methylphthalimide and the emulsifier in the dyeing assistant is 100:25:12.

[0030] (4)Dyeing Heat the mordant to 55 °C, then add it to water at 55 °C and stir evenly to obtain a mordant emulsion; Disperse the disperse dye Disperse Black ECT with warm water at 45 °C first, and prepare a dye solution. Under stirring, add acetic acid and the mordant emulsion in sequence to obtain a disperse dye; Then take the disperse dye and heat it up to 42 °C, add the modified polyester fabric, heat it up to 62 °C, keep it warm for 55 min, then take out the fabric, wash it with water and dry it to obtain a dyed polyester fabric; The mass ratio of the mordant to water in the mordant emulsion is 1:48; The mass ratio of the disperse dye, warm water, pH buffer solution and mordant emulsion in the disperse dye is 1:11:3:60; The mass ratio of the modified polyester fabric to the disperse dye is 1:18.

[0031] Example 3 A dyeing method for polyester fabric, comprising the following steps: alkali weight reduction treatment, preparation of modified polyester fabric, preparation of mordant, and dyeing.

[0032] (1) Alkali weight reduction treatment Dissolve accelerator 1227 and PA-9 dispersant in a sodium hydroxide solution at 20 g / L to prepare an alkali treatment solution, so that the concentration of the accelerator in the alkali treatment solution is 1 g / L and the concentration of the dispersant is 2 g / L. Immerse the polyester fabric in the alkali treatment solution, soak it at 90 °C for 30 min, then wash it thoroughly with water, neutralize it and dry it to obtain an alkali weight reduction treated polyester fabric; The mass ratio of the polyester fabric to the alkali treatment solution is 1:25.

[0033] (2) Preparation of modified polyester fabric A. Fabric pretreatment Immerse the alkali weight reduction treated polyester fabric in an aqueous solution of diethylenetriamine at a concentration of 1.5 wt%, soak it at 35 °C for 15 minutes, roll it to make the fabric wet weight 220%, heat it at 170 °C for 10 min, wash it with water and dry it to obtain a pretreated polyester fabric; The mass ratio of the alkali weight reduction treated polyester fabric to the diethylenetriamine aqueous solution is 1:40.

[0034] B. Modification Immerse the pretreated polyester fabric in modification liquid A, soak it at 15 °C for 4 minutes, roll it to make the polyester fabric wet weight 220%, heat it at 45 °C for 8 min, wash it with water 5 times, roll it to obtain a wet fabric with a wet weight of 190%. Then immerse the wet fabric in modification liquid B, soak it at 30 °C for 8 minutes, roll it to make the polyester fabric wet weight 220%, heat it at 60 °C for 20 min, take it out, wash it with water and dry it to obtain a modified polyester fabric; The preparation method of the modified liquid A is to dissolve glycidyl decyl dimethyl ammonium chloride in water, adjust the pH to 9.5, and the mass ratio of water to glycidyl decyl dimethyl ammonium chloride is 100:1; The preparation method of the modified liquid B is to dissolve carboxymethyl chitin, ethyl dimethylaminopropyl carbodiimide and N-hydroxysuccinimide in water, adjust the pH to 6, and the mass ratio of water, carboxymethyl chitin, ethyl dimethylaminopropyl carbodiimide and N-hydroxysuccinimide is 100:1.2:1.1:0.7; The mass ratio of the pretreated polyester fabric to the modified liquid A is 1:40; The mass ratio of the wet fabric to the modified liquid B is 2:80.

[0035] The preparation method of the glycidyl decyl dimethyl ammonium chloride is to mix decyl dimethyl tertiary amine with absolute ethanol, raise the temperature to 55°C under a nitrogen atmosphere, dropwise add an ethanol solution of epichlorohydrin with a concentration of 50 wt%, after the dropping is completed, keep the temperature at 55°C and react for 5 h, evaporate the solvent after the reaction, wash the product 5 times with ether, and obtain glycidyl decyl dimethyl ammonium chloride after vacuum drying; The mass ratio of the decyl dimethyl tertiary amine, absolute ethanol, and ethanol solution of epichlorohydrin is 10:8:12.

[0036] (3)Prepare the dyeing assistant Mix fatty acid polyoxyethylene ester, fatty alcohol polyoxyethylene ether and n-butanol evenly to prepare an emulsifier; mix diethylene glycol dibenzoate, N-methyl phthalimide with the emulsifier to prepare the dyeing assistant; The HLB value of the fatty acid polyoxyethylene ester is 12.9; The HLB value of the fatty alcohol polyoxyethylene ether is 6.5; The mass ratio of the fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester and n-butanol in the emulsifier is 20:8:2; The mass ratio of diethylene glycol dibenzoate, N-methyl phthalimide and the emulsifier in the dyeing assistant is 100:30:15.

[0037] (4)Dyeing Heat the dyeing assistant to 60°C, then add it to water at 60°C and stir evenly to obtain a dyeing assistant emulsion; disperse the disperse dye Disperse Black ECT first with warm water at 50°C to prepare a dyeing solution, and under stirring, add acetic acid and the dyeing assistant emulsion in sequence to obtain the disperse dye; then take the disperse dye and raise the temperature to 45°C, add the modified polyester fabric, raise the temperature to 65°C, keep warm for 50 min, then take out the fabric, wash it with water and dry it to obtain the dyed polyester fabric; The mass ratio of the dyeing assistant to water in the dyeing assistant emulsion is 1:50; The mass ratio of the disperse dye, warm water, pH buffer, and dyeing assistant emulsion in the disperse dye is 1:12:5:80; The mass ratio of the modified polyester fabric to the disperse dye is 1:20.

[0038] Comparative Example 1 Comparative Example 1 uses the dyeing method of the polyester fabric described in Example 2. The difference is that in the step of preparing the pretreated polyester fabric, the fabric pretreatment step is omitted, and in the modification step, alkali weight reduction treatment of the polyester fabric is used to replace the pretreated polyester fabric, and the remaining steps are the same.

[0039] Comparative Example 2 Comparative Example 2 uses the dyeing method of the polyester fabric described in Example 2. The difference is that in the modification step of preparing the modified polyester fabric, the addition of ethyl dimethylaminopropyl carbodiimide and N-hydroxysuccinimide in the modified liquid B is omitted, and the remaining steps are the same.

[0040] Comparative Example 3 Comparative Example 3 uses the dyeing method of the polyester fabric described in Example 2. The difference is that in the step of preparing the dyeing assistant, the addition of diethylene glycol dibenzoate is omitted, and N-methyl phthalimide of the same mass is used to replace diethylene glycol dibenzoate. The modified step of preparing the dyeing assistant is as follows: Mix fatty acid polyoxyethylene ester, fatty alcohol polyoxyethylene ether, and n-butanol evenly to prepare an emulsifier; mix N-methyl phthalimide with the emulsifier to prepare a dyeing assistant; The HLB value of the fatty acid polyoxyethylene ester is 12.6; The HLB value of the fatty alcohol polyoxyethylene ether is 6.1; The mass ratio of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, and n-butanol in the emulsifier is 20:7:1.5; The mass ratio of N-methyl phthalimide to the emulsifier in the dyeing assistant is 125:12.

[0041] Comparative Example 4 Comparative Example 4 uses the dyeing method of the polyester fabric described in Example 2. The difference is that in the step of preparing the dyeing assistant, the addition of N-methyl phthalimide is omitted, and diethylene glycol dibenzoate of the same mass is used to replace N-methyl phthalimide. The modified step of preparing the dyeing assistant is as follows: Mix fatty acid polyoxyethylene ester, fatty alcohol polyoxyethylene ether, and n-butanol evenly to prepare an emulsifier; mix diethylene glycol dibenzoate with the emulsifier to prepare a dyeing assistant; The HLB value of the fatty acid polyoxyethylene ester is 12.6; The HLB value of the fatty alcohol polyoxyethylene ether is 6.1; In the emulsifier, the mass ratio of the fatty alcohol polyoxyethylene ether, the fatty acid polyoxyethylene ester and the n-butanol is 20:7:1.5; In the auxiliary dyeing agent, the mass ratio of the diethylene glycol dibenzoate and the emulsifier is 125:12.

[0042] Test Example 1 For the dyed polyester fabrics prepared in Examples 1-3 and Comparative Examples 1-4, the exhaustion percentage of the disperse dye was determined by the residual liquor method. The blank dye solution and the residual liquor after dyeing were diluted by a certain multiple respectively, and then 3 mL of the diluted blank dye solution and the dyed solution after dyeing were respectively taken and placed in a 10 mL volumetric flask, and acetone was added to the scale, and the absorbance was measured. The exhaustion percentage E was calculated according to the following formula, where A0 is the absorbance measured at the maximum absorption wavelength after diluting the blank dye solution by n0 times, and A1 is the absorbance measured at the maximum absorption wavelength after diluting the residual liquor after dyeing by n1 times; the test results are shown in Table 1.

[0043] E = (1 - A1n1 / A0n0) × 100% Table 1 Exhaustion percentage

[0044] Test Example 2 For the dyed polyester fabrics prepared in Examples 1-3 and Comparative Examples 1-4, the apparent color depth value K / S was detected. The apparent color depth value K / S index of the fabric was measured by a spectrophotometer. The test light source was D65, the viewing angle was 10°, the sample was folded 4 layers, and it was measured 3 times, and the average value was taken; the test results are shown in Table 2.

[0045] Table 2 Apparent color depth value K / S

[0046] It can be seen from the above test results that the exhaustion percentages and the apparent color depth values of Examples 1-3 are higher than those of Comparative Examples 1-4, indicating that the fabric pretreatment step, the addition of ethyl dimethylaminopropyl carbodiimide and N-hydroxysuccinimide in the modified liquid B, and the synergistic effect of the diethylene glycol dibenzoate and N-methyl phthalimide in the auxiliary dyeing agent can improve the exhaustion percentage and the apparent color depth value of the dyed polyester fabric.

[0047] In the fabric pretreatment step, diethylenetriamine is used to soak and then roll-press and heat-treat the polyester fabric to construct an aminated surface on the surface of the polyester fabric, increasing the reactive sites. Then, glycidyl decyldimethylammonium chloride is grafted onto the fiber surface of the polyester fabric, so that the fabric surface no longer carries negative charges but carries a certain number of positive charges. As a result, the negatively charged coating particles are adsorbed on the fiber surface in the form of electrostatic force, increasing the coating density on the fabric surface. The large coating density difference between the inside and the surface of the fabric fibers promotes the diffusion of dyes into the fiber interior, increasing the dyeing speed, and further increasing the dye uptake percentage and the apparent color depth value.

[0048] By controlling the concentration of glycidyl decyldimethylammonium chloride in the modification liquid A and the reaction temperature, time, etc., only part of the amino groups participate in the reaction of grafting glycidyl decyldimethylammonium chloride. The remaining amino active sites react with the carboxyl groups of carboxymethyl chitin under the promotion of ethyl dimethylaminopropyl carbodiimide to bond the carboxymethyl chitin to the fiber surface of the polyester fabric. The carboxymethyl chitin attached to the fiber surface contains a large number of functional groups such as carboxyl and hydroxyl groups, enhancing the affinity of the fabric for anionic dyes and increasing the dyeing speed and color yield.

[0049] Adding diethylene glycol dibenzoate to the dye assistant has a certain similarity with the molecular monomers of polyester fibers. After emulsification, it can expand the polyester fibers, weaken the intermolecular forces of the fibers, and lower their glass transition temperature and crystallinity; N-methyl phthalimide can enter the interior of the polyester fibers to ammonolyze the fibers, reducing the crystallinity of the polyester, which is beneficial for low-temperature dyeing; the synergistic effect of diethylene glycol dibenzoate and N-methyl phthalimide can increase the adsorption and dyeing rate of disperse dyes on the surface of polyester fibers, increase the diffusion rate of dyes into the fiber interior, improve the dyeing performance of polyester, and increase the dye uptake percentage and the apparent color depth value of the polyester fabric.

[0050] The dye assistant emulsion obtained after emulsifying the dye assistant is then compounded with the dye liquor, which can increase the solubility and dispersibility of disperse dyes and improve the dyeing performance of disperse dyes.

[0051] Test Example 3 The rubbing fastness of the dyed polyester fabrics prepared in Examples 1-3 and Comparative Examples 1-2 was tested. According to GB / T3920-2008 "Textiles - Tests for colour fastness - Colour fastness to rubbing", it was tested and the fastness grade was evaluated using the grey scale for assessing staining in GB / T 251-2008; the test results are shown in Table 3.

[0052] Table 3 Rubbing fastness grade

[0053] Test Example 4 The color fastness to washing of the dyed polyester fabrics prepared in Examples 1-3 and Comparative Examples 1-2 was tested. The color fastness to washing of the polyester fabrics was tested using a wash fastness tester. The test method was carried out in accordance with Test Method C(3) in GB / T 3921-2008 "Textiles - Tests for color fastness - Color fastness to soaping", and the gray scale for assessing change in color in GB / T 251-2008 and the gray scale for assessing staining in GB / T 251-2008 were used to evaluate the color change and staining fastness grades respectively; the test results are shown in Table 4.

[0054] Table 4 Color fastness to washing grades

[0055] It can be seen from the test results in Tables 3-4 that the rubbing fastness grades and color fastness to washing grades of Comparative Example 1 and Comparative Example 2 are significantly lower than those of Example 2, indicating that fabric pretreatment and the addition of ethyl dimethylaminopropyl carbodiimide and N-hydroxysuccinimide in Modifying Solution B can improve the rubbing fastness and color fastness to washing of the dyed polyester fabric.

[0056] In the preparation of the pretreated polyester fabric in Comparative Example 1, the fabric pretreatment step was omitted. There were fewer active sites on the surface of the polyester fabric, making it difficult for glycidyl decyldimethylammonium chloride and carboxymethyl chitin to graft onto the fiber surface, reducing the grafting rate and affecting the dyeing performance of the polyester fabric.

[0057] Based on Example 2, in Comparative Example 2, the addition of ethyl dimethylaminopropyl carbodiimide and N-hydroxysuccinimide in Modifying Solution B was omitted, resulting in carboxymethyl chitin not easily grafting onto the fiber surface of the polyester fabric and affecting the color fastness of the dyed polyester fabric.

[0058] In the modification step, ethyl dimethylaminopropyl carbodiimide in Modifying Solution B can activate the carboxyl groups on carboxymethyl chitin and react with the amino groups on the fiber surface to form amide bonds, promoting the grafting of carboxymethyl chitin onto the fiber surface of the polyester fabric. The added N-hydroxysuccinimide can increase the grafting rate and reduce the occurrence of side reactions. The molecule of carboxymethyl chitin contains a large number of functional groups such as carboxyl and hydroxyl groups. In the dyeing step, these functional groups can react with groups such as hydroxyl and amino groups in the dye molecule to establish chemical bonding, which can effectively fix the dye molecule on the fiber and prevent the dye from falling off during rubbing and washing, improving the color fastness of the polyester fabric.

[0059] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A dyeing method for polyester fabric, characterized in that, The dyeing method of the polyester fabric includes the following steps: alkali weight reduction treatment, preparation of modified polyester fabric, preparation of dyeing assistant, and dyeing; The preparation of the modified polyester fabric includes the following steps: fabric pretreatment, modification; The method of fabric pretreatment is to soak the alkali weight reduction treated polyester fabric in a diethylenetriamine aqueous solution, soak at 30 - 35 °C for 15 - 20 minutes, roll press to make the fabric wet weight 200% ± 20%, heat at 160 - 170 °C for 10 - 15 min, wash with water and dry to obtain the pretreated polyester fabric; The method of modification is to soak the pretreated polyester fabric in modification liquid A, soak at 10 - 15 °C for 4 - 6 minutes, roll press to make the polyester fabric wet weight 200% ± 20%, heat at 40 - 45 °C for 8 - 10 min, wash with water 3 - 5 times, roll press to obtain a wet fabric with a wet weight of 180% ± 10%, then immerse the wet fabric in modification liquid B, soak at 25 - 30 °C for 8 - 10 minutes, roll press to make the polyester fabric wet weight 200% ± 20%, heat at 50 - 60 °C for 20 - 25 min, take out and wash with water and dry to obtain the modified polyester fabric; The preparation method of modification liquid A is to dissolve glycidyl decyldimethylammonium chloride in water and adjust the pH to 8.5 - 9.5; The preparation method of modification liquid B is to dissolve carboxymethyl chitin, ethyl dimethylaminopropyl carbodiimide and N - hydroxysuccinimide in water and adjust the pH to 4 - 6.

2. The dyeing method of a polyester fabric according to claim 1, characterized in that, The method of preparing the dyeing assistant is to mix fatty acid polyoxyethylene ester, fatty alcohol polyoxyethylene ether and n - butanol evenly to prepare an emulsifier; mix diethylene glycol dibenzoate, N - methylphthalimide and the emulsifier to prepare the dyeing assistant.

3. The dyeing method of a polyester fabric according to claim 2, wherein The HLB value of the fatty acid polyoxyethylene ester is 11.8 - 12.9; The HLB value of the fatty alcohol polyoxyethylene ether is 5.4 - 6.5; The mass ratio of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester and n - butanol in the emulsifier is 20:6 - 8:1 - 2; The mass ratio of diethylene glycol dibenzoate, N - methylphthalimide and the emulsifier in the dyeing assistant is 100:20 - 30:10 - 15.

4. A dyeing method for a polyester fabric according to claim 3, characterized in that, The method of dyeing is to heat the dyeing assistant to 50 - 60 °C, then add it to water at 50 - 60 °C and stir evenly to obtain a dyeing assistant emulsion; disperse the disperse dye first with warm water at 40 - 50 °C to prepare a dyeing solution, and under stirring, add a pH buffer solution and the dyeing assistant emulsion in sequence to obtain the disperse dye; then raise the temperature of the disperse dye to 40 - 45 °C, add the modified polyester fabric, raise the temperature to 60 - 65 °C, keep warm for 50 - 60 min, take out the fabric, wash with water and dry to obtain the dyed polyester fabric.

5. The dyeing method of a polyester fabric according to claim 4, wherein The pH buffer solution is acetic acid; The mass ratio of the dyeing assistant and water in the dyeing assistant emulsion is 1:45 - 50; The mass ratio of the disperse dye, warm water, pH buffer solution, and dyeing assistant emulsion in the disperse dye is 1:10 - 12:2 - 5:50 - 80; The mass ratio of the modified polyester fabric to the disperse dye is 1:15 - 20.

6. A dyeing method for a polyester fabric according to claim 1, characterized in that, In the fabric pretreatment step, the concentration of diethylenetriamine in the diethylenetriamine aqueous solution is 1 - 1.5 wt%, and the mass ratio of the alkali weight reduction treated polyester fabric to the diethylenetriamine aqueous solution is 1:20 - 40.

7. A method for dyeing a polyester fabric according to claim 1, characterized in that, In the modification step, the mass ratio of water to glycidyl decyldimethylammonium chloride in modification liquid A is 100:0.8 - 1, and the mass ratio of water, carboxymethyl chitin, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and N-hydroxysuccinimide in modification liquid B is 100:0.8 - 1.2:0.9 - 1.1:0.5 - 0.

7.

8. A method for dyeing a polyester fabric according to claim 1, characterized in that In the modification step, the mass ratio of the pretreated polyester fabric to modification liquid A is 1:30 - 40, and the mass ratio of the wet fabric to modification liquid B is 2:70 - 80.

9. A method for dyeing a polyester fabric according to claim 1, characterized in that, The method of the alkali weight reduction treatment is to dissolve the accelerator and dispersant in the sodium hydroxide solution to prepare an alkali treatment solution, immerse the polyester fabric in the alkali treatment solution, impregnate it at 80 - 90 °C for 30 - 40 min, and then wash, neutralize, and dry it thoroughly to obtain the alkali weight reduction treated polyester fabric.

10. A dyeing method for a polyester fabric according to claim 9, wherein the concentration of the sodium hydroxide solution is 10 - 20 g / L; the accelerator is accelerator 1227 or accelerator Q-12; the dispersant is PA-9 dispersant; the concentration of the accelerator in the alkali treatment solution is 0.5 - 1 g / L; the concentration of the dispersant in the alkali treatment solution is 1 - 2 g / L; the mass ratio of the polyester fabric to the alkali treatment solution is 1:20 - 25.

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