High-definition chinlon digital printing process

Abstract

The invention discloses a high-definition chinlon digital printing technology, and belongs to the technical field of fabric digital printing, the technology comprises fabric pretreatment and inkjet printing, and a treatment liquid comprises the following components by weight: 91-93 parts of water, 3-4 parts of a hyperbranched water-soluble polymer, 4-5 parts of guar gum, 3-4 parts of urea, 0.4-0.6 part of an inorganic salt, and 0.001-0.1 part of an acidity regulator. The pH value of the treating fluid is 4.2 to 4.8; the hyperbranched water-soluble polymer is prepared from a monomer 1 containing a secondary amine group and a monomer 2 containing pyrrolidone through hyperbranched polymerization. The treating fluid used in the digital printing process for chinlon provided by the invention contains a hyperbranched water-soluble polymer with an amino and pyrrolidone structure, and two groups respectively act on acid dye molecules and chinlon fibers; the chinlon digital printing product treated by the treating fluid has the advantages of high definition, good leveling property and high color fastness.

Description

Technical Field

[0001] The present invention belongs to the technical field of digital printing of fabrics, and particularly relates to a high-definition digital printing process for polyamide. Background Art

[0002] Inkjet printing has become increasingly important in the printing and dyeing industry in recent years because it does not require processes such as plate making, color matching, proofing, and roller manufacturing. Compared with traditional printing, it has many obvious advantages, such as high pattern fineness; high production flexibility, "quick response, diversification"; environmentally friendly, high ink utilization rate, low noise, low water consumption, reduced waste liquid discharge, and low energy consumption, meeting the requirements of low-carbon environmental protection. Acid dyes, disperse dyes, and reactive dye inks can often be used for inkjet printing of polyamide. Among them, acid dyes are one of the most commonly used dyes for polyamide dyeing and are widely used in the dyeing of polyamide clothing, carpets, sportswear, etc.

[0003] However, the amino content of polyamide is relatively low, and there are limited dyeing sites on the fabric. Inkjet printing requires pretreatment and post-treatment of it. Otherwise, a large amount of residual dye will float on the surface of the printed fabric, easily leading to ink bleeding and affecting the clarity of printing. Therefore, it is still necessary to develop a new digital printing process to solve the problem of low clarity in digital printing of polyamide. Summary of the Invention

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a high-definition digital printing process for polyamide. The polyamide is pretreated with a treatment solution containing a hyperbranched water-soluble polymer. The product obtained by the digital printing process after the treated polyamide has the advantages of high clarity, good levelness, and high color fastness.

[0005] The technical solution for achieving the object of the present invention is as follows: A high-definition digital printing process for polyamide, comprising the following steps:

[0006] Preparing a treatment solution → Sizing the fabric → Drying I → Digital printing → Drying II → Steam heating → Washing I → Soaping → Washing II → Drying III;

[0007] The treatment solution, by weight, comprises the following components: 91 - 93 parts of water, 3 - 4 parts of hyperbranched water-soluble polymer, 4 - 5 parts of guar gum, 3 - 4 parts of urea, 0.4 - 0.6 parts of inorganic salt, 0.001 - 0.1 parts of acidity regulator, and the pH value of the treatment solution is 4.2 - 4.8;

[0008] The hyperbranched water-soluble polymer is hyperbranched polymerized from monomer 1 of formula I and monomer 2 of formula II:

[0009]

[0010] Specifically, when the pH is in the range of 4.2 to 4.8, the amino groups in the hyperbranched water-soluble polymer and the polyamide fiber can be converted into amino positive ions.

[0011] Preferably, the molar ratio of monomer 1 to monomer 2 is (30 - 60):1; the number-average molecular weight of the hyperbranched water-soluble polymer is 10,000 - 20,000, and the molecular weight distribution coefficient is 1.5 - 2; the number-average molecular weight and the molecular weight distribution coefficient are measured by gel permeation chromatography.

[0012] The preparation method of the hyperbranched water-soluble polymer is as follows:

[0013] 1) Under an inert gas atmosphere, add 9 - 12 eq of monomer 1, 0.21 - 0.3 eq of hyperbranched initiator, 0.25 - 0.4 eq of cuprous bromide, and 50 - 60 eq of anhydrous anisole to a Schlenk flask. After freeze-thaw degassing, add 0.3 - 0.5 eq of N,N,N′,N″,N″-pentamethyldiethylenetriamine. Stir at 55 - 65 °C for 1 - 2 h, then add 1.5 - 3 eq of monomer 2, and continue to stir for 1 - 2 h. Pass oxygen to terminate the reaction. Filter out copper ions by column chromatography. The obtained solution is concentrated by a rotary evaporator, precipitated in cold methanol, filtered, and the solid product is collected and dried.

[0014] 2) Under an inert gas atmosphere, at 0 °C, add 1 eq of the product obtained in step 1, 30 - 35 eq of trifluoroacetic acid and 30 - 35 eq of dichloromethane to a three-necked flask. Heat to 30 - 35 °C and continue to stir for 2 - 4 h. Wash with saturated sodium bicarbonate solution, collect the organic phase, and spin-dry it with a rotary evaporator to obtain the hyperbranched water-soluble polymer.

[0015] It should be noted that in the present invention, the N-tert-butoxycarbonyl (Boc) group is used to protect the amino group. On the one hand, it prevents the competitive reaction between the amino group and the hydroxyl group with methacryloyl chloride. On the other hand, it reduces the activity of the amino group and prevents it from complexing with copper during polymerization, resulting in the inactivation of the catalyst.

[0016] Preferably, the drying I temperature is 100 - 120 °C; the drying II temperature is 95 - 105 °C; the steaming temperature is 100 - 105 °C, and the state is normal pressure saturated steam.

[0017] Preferably, for soaping, 1 - 2 g / L of standard soap flakes are used, the temperature is 90 - 100 °C, and the washing time is 8 - 12 min; for the first water washing, it is cold water washing for 4 - 6 min followed by warm water washing at 35 - 45 °C for 4 - 6 min; for the second water washing, it is warm water washing at 35 - 45 °C for 4 - 6 min followed by cold water washing for 4 - 6 min; the bath ratios for soaping, the first water washing, and the second water washing are all 40:1 - 20:1.

[0018] Preferably, the inorganic salt is one or more of chloride salts, sulfate salts, acetate salts, and carbonate salts.

[0019] More preferably, the inorganic salt is ammonium acetate.

[0020] Preferably, the acidity regulator is one or more of acetic acid, hydrochloric acid, sulfuric acid, and oxalic acid.

[0021] More preferably, the acidity regulator is acetic acid.

[0022] The cations in the inorganic salt dispersed in the fiber can adsorb negatively charged dye molecules, improving the color depth of the printing; when ammonium acetate and acetic acid are used for acidity adjustment, a buffer solution is formed, which can ensure the stability of the solution when adjusting the pH value.

[0023] Specifically, the monomer 1 is prepared by the following method: Add 1.0 eq of N-(tert-butoxycarbonyl) ethanolamine, 1.5 - 2.0 eq of triethylamine, and 20 eq of anhydrous toluene to a three-necked flask. Under an inert gas atmosphere, dissolve 1.5 - 2.0 eq of acryloyl chloride in 20 eq of anhydrous toluene at a temperature of -10 to 5 °C and then slowly add it to the three-necked flask using a syringe. Stir the reaction at room temperature for 36 - 48 h, filter, concentrate the obtained solution, dissolve it in dichloromethane, wash it with an aqueous sodium hydroxide solution, collect the organic phase, and dry it by rotary evaporation to obtain monomer 1.

[0024] Specifically, the monomer 2 is prepared by the following method: Add 1.0 eq of N-hydroxyethyl-2-pyrrolidone, 1.5 - 2.0 eq of triethylamine, and 20 eq of anhydrous toluene to a three-necked flask. Under an inert gas atmosphere, dissolve 1.5 - 2.0 eq of acryloyl chloride in 20 eq of anhydrous toluene at a temperature of -10 to 5 °C and then slowly add it to the three-necked flask using a syringe. Stir the reaction at room temperature for 36 - 48 h, filter, concentrate the obtained solution, dissolve it in dichloromethane, wash it with an aqueous sodium hydroxide solution, collect the organic phase, and dry it by rotary evaporation to obtain monomer 2.

[0025] Specifically, the hyperbranched initiator is 2-(2-bromoisobutoxy)ethyl acrylate, which can be obtained commercially or prepared by oneself. Preferably, the hyperbranched initiator is prepared by the following method: Add 1 eq of 2-hydroxyethyl acrylate, 1.5 - 2.0 eq of triethylamine, and 40 - 50 eq of dichloromethane solvent to a three-necked flask. Under an inert gas atmosphere, slowly drop 1.2 - 1.3 eq of 2-bromo-2-methylpropionyl bromide into the three-necked flask at a temperature of -10 to 5 °C. Stir at room temperature for 12 - 24 h. After the reaction is completed, wash it successively with saturated sodium bicarbonate solution and saturated sodium chloride solution, dry it with anhydrous magnesium sulfate, and then separate and purify it by silica gel column to obtain the hyperbranched initiator.

[0026] Specifically, the concentration of the sodium hydroxide aqueous solution is 1 to 2 mol / L.

[0027] Beneficial effects

[0028] The present invention includes the following beneficial effects: A high-definition polyamide digital printing process provided by the present invention uses a treatment solution containing a hyperbranched water-soluble polymer to pretreat polyamide. The core of the hyperbranched water-soluble polymer has a large number of amino groups, and the amino cations formed under acidic conditions will repel each other, forming pores large enough to adsorb negatively charged dye molecules, preventing the dye molecules from diffusing too fast during coloring and resulting in reduced clarity. The shell of the hyperbranched water-soluble polymer has a large number of pyrrolidone and acrylate structures, which are similar in polarity to polyamide. Due to its compact spherical structure, part of it can more easily penetrate into the micropores and amorphous regions of polyamide fibers, and the other part can form a more uniform coating on the surface of polyamide. The spherical structure can form a microscopic "concave-convex" structure on the fiber surface, which helps to better control the shape and size of ink droplets. During high-temperature heating, the hyperbranched water-soluble polymer provides a large number of dyeing sites, and the amino groups further react with pyrrolidone and acidic dye molecules, thereby crosslinking into a film and adhering to the fabric surface for color fixation. The polyamide digital printing products obtained after being treated with this treatment solution have the advantages of high clarity, good levelness, and high color fastness. Description of the drawings

[0029] Figure 1 It is the synthesis route of the hyperbranched water-soluble polymer and its monomer of the present invention;

[0030] Figure 2 It is the 1H NMR spectrum of monomer 1 of the present invention;

[0031] Figure 3 It is the 1H NMR spectrum of monomer 2 of the present invention. Specific embodiments

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0033] In the embodiments, the experimental methods used are all conventional methods unless otherwise specified, and the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0034] Now, the raw materials and equipment used in the examples and comparative examples are described as follows:

[0035] Conductive Belt Digital Printer: Model DTBS-1638, purchased from Chengdu Jinzhida Digital Technology Co., Ltd.;

[0036] Nylon Fabric: Nylon plain cloth, yarn count 4040, 180g, purchased from Haining Baichuang Textile Co., Ltd.;

[0037] Acid Dyes: Acid Yellow, Acid Black, Acid Blue, Acid Red, purchased from Shangyu Guangming Chemical Co., Ltd.;

[0038] Standard Soap Flakes: International standard soap powder, purchased from Standard Group Co., Ltd.;

[0039] Guar Gum: purchased from Zhengzhou Poole Chemical Products Co., Ltd.;

[0040] Inorganic Salt: Ammonium Acetate, product number A800996, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0041] Acidity Regulator: Acetic Acid, product number A801301, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0042] Copper(I) Bromide: product number C804582, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0043] N,N,N',N',N''-Pentamethyldiethylenetriamine: product number N822749, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0044] Trifluoroacetic Acid: product number T818778, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0045] N-(tert-Butoxycarbonyl)ethanolamine: product number N802367, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0046] Methacryloyl Chloride: product number A800376, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0047] 2-Hydroxyethyl Acrylate: product number H810915, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0048] 2-Bromoisobutyryl Bromide: product number B802437, purchased from Shanghai Macklin Biochemical Co., Ltd.;

[0049] O-Hydroxyethyl-2-pyrrolidone: product number H799592, purchased from Shanghai Macklin Biochemical Co., Ltd.

[0050] Monomer 1

[0051] Into a three-necked flask, add 1.0 eq of N-(tert-butoxycarbonyl)ethanolamine, 2.0 eq of triethylamine, and 20 eq of anhydrous toluene. Under an inert gas atmosphere and at 0 °C, dissolve 1.8 eq of acryloyl chloride in 20 eq of anhydrous toluene, and then slowly add it to the three-necked flask using a syringe. Stir the reaction at room temperature for 40 h, filter, concentrate the resulting solution, dissolve it in dichloromethane, wash it 3 times with an aqueous sodium hydroxide solution, collect the organic phase, evaporate it to obtain monomer 1.

[0052] Monomer 2

[0053] Into a three-necked flask, add 1.0 eq of N-hydroxyethyl-2-pyrrolidone, 2.0 eq of triethylamine, and 20 eq of anhydrous toluene. Under an inert gas atmosphere and at 0 °C, dissolve 1.8 eq of acryloyl chloride in 20 eq of anhydrous toluene, and then slowly add it to the three-necked flask using a syringe. Stir the reaction at room temperature for 40 h, filter, concentrate the resulting solution, dissolve it in dichloromethane, wash it 3 times with an aqueous sodium hydroxide solution, collect the organic phase, and dry it by rotary evaporation to obtain monomer 2.

[0054] Hyperbranched initiator

[0055] Into a three-necked flask, add 1 eq of 2-hydroxyethyl acrylate, 2.0 eq of triethylamine, and 45 eq of dichloromethane solvent. Under an inert gas atmosphere and at -10 °C, slowly drop 1.3 eq of 2-bromo-2-methylpropanoyl bromide into the three-necked flask. Stir at room temperature for 24 h. After the reaction is completed, wash it with saturated sodium bicarbonate solution and saturated sodium chloride solution, dry it with anhydrous magnesium sulfate, and then separate and purify it by silica gel column chromatography to obtain the hyperbranched initiator.

[0056] Hyperbranched water-soluble polymer 1

[0057] Under an inert gas atmosphere, into a Schlenk flask, add 9 eq of monomer 1, 0.21 eq of hyperbranched initiator, 0.25 eq of copper(I) bromide, 50 eq of anhydrous anisole. After freeze-thaw degassing 3 times, add 0.3 eq of N,N,N′,N″,N″-pentamethyldiethylenetriamine, stir at 60 °C for 2 h, then add 1.5 eq of monomer 2, continue to stir for 1 h, pass in oxygen to terminate the reaction, remove copper ions by column chromatography, concentrate the resulting solution, precipitate it in cold methanol, filter, collect the solid product and dry it;

[0058] Under an inert gas atmosphere and at 0 °C, into a three-necked flask, add 1 eq of the product obtained in step 1), 30 eq of trifluoroacetic acid and 30 eq of dichloromethane. Raise the temperature to 30 °C and continue to stir for 2 h. Wash it 3 times with saturated sodium bicarbonate solution, collect the organic phase, and dry it by rotary evaporation to obtain hyperbranched water-soluble polymer 1.

[0059] Hyperbranched water-soluble polymer 2

[0060] Under an inert gas atmosphere, add 12 eq of monomer 1, 0.3 eq of hyperbranched initiator, 0.4 eq of cuprous bromide, and 60 eq of anhydrous anisole into a Schlenk flask. After freeze-thaw degassing three times, add 0.5 eq of N,N,N′,N″,N″-pentamethyldiethylenetriamine, stir at 60 °C for 1 h, then add 3 eq of monomer 2, continue stirring for 2 h, introduce oxygen to terminate the reaction, remove copper ions by column chromatography, concentrate the obtained solution, precipitate in cold methanol, filter, and collect the solid product and dry it;

[0061] Under an inert gas atmosphere and at 0 °C, add 1 eq of the product obtained in step 1), 30 eq of trifluoroacetic acid and 30 eq of dichloromethane into a three-necked flask, raise the temperature to 30 °C and continue stirring for 2 h, wash three times with saturated sodium bicarbonate solution, collect the organic phase, and dry it by rotary evaporation to obtain hyperbranched water-soluble polymer 2.

[0062] Hyperbranched water-soluble polymer 3

[0063] The preparation method is different from that of hyperbranched polymer 2 in that 3 eq of monomer 2 is replaced by 3 eq of monomer 1;

[0064] Hyperbranched water-soluble polymer 4

[0065] The preparation method is different from that of hyperbranched polymer 2 in that 12 eq of monomer 1 is replaced by 12 eq of monomer 2;

[0066] Linear water-soluble polymer

[0067] Under an inert gas atmosphere, add 12 eq of monomer 1, 0.3 eq of 2-bromoisobutyryl bromide, 0.4 eq of cuprous bromide, and 60 eq of anhydrous anisole into a Schlenk flask. After freeze-thaw degassing three times, under a nitrogen atmosphere, add 0.5 eq of N,N,N′,N″,N″-pentamethyldiethylenetriamine, stir at 60 °C for 2 h, then add 3 eq of monomer 2, continue stirring for 1 h. After the reaction is completed, introduce oxygen under ice bath conditions, remove copper ions by column chromatography, concentrate the obtained solution, precipitate in cold methanol, filter, and collect the solid product and dry it;

[0068] In a three-necked flask, at 0 °C, add 1 eq of the product obtained in step 1), 30 eq of trifluoroacetic acid and 30 eq of dichloromethane, raise the temperature to 30 °C and continue stirring for 2 h, wash three times with saturated sodium bicarbonate solution, collect the organic phase, and dry it by rotary evaporation to obtain linear water-soluble polymer.

[0069] The following are the test methods for the performance parameters involved in the present invention:

[0070] Number-average molecular weight: Test the polymer before hydrolysis by gel permeation chromatography - differential detector (Waters, USA);

[0071] Molecular weight distribution coefficient: Tested for the polymer before hydrolysis by gel permeation chromatography - differential detector (Waters, USA);

[0072] 1H NMR spectrum: 400 MHz nuclear magnetic resonance spectrometer (Bruker, Germany);

[0073] Table 1 Physicochemical property tests of hyperbranched water - soluble polymers

[0074]

[0075] From the data in Table 1, the number - average molecular weight of the hyperbranched water - soluble polymer is 10,000 - 20,000, and the molecular weight distribution coefficient is 1.5 - 2; It can be seen from the molecular weight distribution coefficient that the molecular weight distribution coefficients of hyperbranched water - soluble polymers 1 - 4 are larger, and those of linear water - soluble polymers are smaller, which is consistent with the molecular weight distribution range law of hyperbranched and linear polymers obtained by common ATRP polymerization. Figures 2-3 1H NMR spectra of monomer 1 and monomer 2.

[0076] Examples and comparative examples

[0077] A high - definition nylon digital printing process includes the following steps:

[0078] Prepare the treatment liquid → Sizing the fabric → Drying I → Digital printing → Drying II → Steam heating → Washing I → Soaping → Washing II → Drying III;

[0079] The formula of the treatment liquid is shown in Table 2. The preparation method of the treatment liquid is to add 91 - 93 parts of water, 3 - 4 parts of hyperbranched water - soluble polymer, 4 - 5 parts of guar gum, and 0.4 - 0.6 parts of inorganic salt into a container, and add an acidity regulator to adjust the pH value to 4.5;

[0080] The specific steps of sizing the fabric are as follows: Immerse the nylon fabric in the treatment liquid for 15 minutes and then take it out, squeeze out the excess solution through a padding mangle. The rotation speed of the padding mangle is set to 30 r / min, and the pressure is set to 0.3 Mpa. After two - dip two - roll, place the fabric in an oven for drying, and the drying temperature is set to 100 °C;

[0081] The specific steps of digital printing are as follows: Fix the nylon fabric and send it into a belt - type digital printer, and use Adobe Illustrator 2021 software for single - channel printer printing. The printing content of inkjet printing is respectively a 15 cm × 4 cm CMYK four - color block and a 353 μm line;

[0082] Subsequent drying I (temperature 120°C) → steaming (standard pressure, temperature 100°C) → washing I (cold water washing for 5 min, warm water washing at 40°C for 4 - 6 min) → soaping (standard soap flakes 1.5 g / L, temperature 90°C, 12 min) → washing II (warm water washing at 40°C for 5 min, cold water washing for 5 min) → drying II (temperature 100°C) steps are carried out to obtain printed polyamide, and the bath ratio is 30:1 for all;

[0083] The following performance tests were carried out on the digital printed polyamide fabrics of the examples and comparative examples:

[0084] (1) K / S value: Measured using a DataColor850 colorimeter, with the light source set to D65, the viewing angle to 10°, the aperture selected as medium aperture (20 mm), and the fabric folded four times;

[0085] (2) Fixation rate: In the formula, (K / S) f0 is the value measured before soaping, and (K / S) f is the value measured after soaping.

[0086] (3) Rubbing fastness: Tested in accordance with the standard GB / T 3920 - 2008 "Textiles - Tests for colour fastness - Colour fastness to rubbing", and the degree of staining on the rubbing cloth is used as the evaluation standard;

[0087] (4) Printing contour clarity: Observe the printed straight lines on the fabric through a three - dimensional ultra - depth - of - field digital microscope, and evaluate the printing contour clarity by the line width change rate: The larger the line width change rate W value, the higher the degree of ink bleeding and the worse the clarity of the printed pattern. In the formula, D0 is the printed line width (353 μm), and D is the measured line width;

[0088] Table 2 Formulation of treatment liquid

[0089]

[0090] Table 3 Test results of the performance of printed fabrics

[0091]

[0092] As can be seen from the data in Table 3, the printed polyamide obtained by treating with the treatment liquids in Examples 1 - 3 has the advantages of high K / S value, high fixation rate, low line width change rate (i.e., high clarity), and high rubbing fastness grade.

[0093] From the data of Comparative Examples 1 to 2 in Table 3, it can be seen that the printed polyamide prepared by treating with the hyperbranched water-soluble polymer 3 of amino groups prepared from monomer 1 or the hyperbranched water-soluble polymer 4 prepared from monomer 2 is inferior to Examples 1 to 3 in all aspects characterized. Although the amino groups can adsorb a large number of dye molecules, there are no reactive groups between them and polyamide fibers during the color fixation stage; although the cyclic amide in the pyrrolidone of monomer 2 can react with polyamide fibers during the color fixation stage, its adsorption ability for dye molecules is weak; from Comparative Example 3, it can be seen that adding a linear water-soluble polymer also has a good effect, in which the amino groups and cyclic amides can play the role of adsorbing dye molecules and polyamide fibers, but the effect is not as excellent as that of the hyperbranched water-soluble polymer; from the data of Comparative Examples 4 and 5, it can be seen that not adding or adding too much of the hyperbranched water-soluble polymer prepared by the present invention will have a great impact on the printing and dyeing performance. Adding too much may cause the ink droplets to aggregate on the surface of polyamide fibers, affecting the diffusion behavior of the ink droplets.

[0094] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A high-definition nylon digital printing process, characterized in that: The following steps are involved: Preparation of treatment liquid - fabric sizing - drying I → digital printing → drying II → steaming → washing I → soap washing → washing II → drying III; The treatment liquid comprises the following components by weight: 91-93 parts of water, 3-4 parts of hyperbranched water-soluble polymer, 4-5 parts of guar gum, 3-4 parts of urea, 0.4-0.6 parts of inorganic salt, 0.001-0.1 parts of acidity regulator, and the pH value of the treatment liquid is 4.2-4.8; The hyperbranched water-soluble polymer is prepared by hyperbranching polymerization of monomer 1 of formula I and monomer 2 of formula II:

2. The nylon digital printing process according to claim 1, characterized in that: The preparation method of the hyperbranched water-soluble polymer is as follows: 1) In an inert gas atmosphere, 9-12 eq of monomer 1, 0.21-0.3 eq of hyperbranched initiator, 0.25-0.4 eq of cuprous bromide, and 50-60 eq of anhydrous anisole are added to a Shrek bottle. After freeze-thaw degassing, 0.3-0.5 eq of N,N,N′,N″,N″-pentamethyldiethylenetriamine is added. After stirring at 55-65° C. for 1-2 h, 1.5-3 eq of monomer 2 is added. Stirring is continued for 1-2 h. Oxygen is introduced to terminate the reaction. Copper ions are filtered out by column chromatography. The resulting solution is concentrated by rotary evaporator, precipitated in cold methanol, filtered, and the solid product is collected and dried; 2) Under an inert gas atmosphere and at a temperature of 0° C., add 1 eq of the product obtained in step 1), 30-35 eq of trifluoroacetic acid and 30-35 eq of dichloromethane into a three-necked flask, raise the temperature to 30-35° C. and continue stirring for 2-4 h, wash with a saturated sodium bicarbonate solution, collect the organic phase, and dry it on a rotary evaporator to obtain a hyperbranched water-soluble polymer.

3. The nylon digital printing process according to claim 1, characterized in that: The drying temperature is 100-120°C; the drying II temperature is 95-105°C; the steaming temperature is 100-105°C, and the state is saturated steam at normal pressure.

4. The nylon digital printing process according to claim 1, characterized in that: The fabric sizing step is: immersing the nylon fabric in the treatment solution for 10 to 15 minutes, then taking it out, squeezing out the excess solution with a rolling mill, the speed of the rolling mill is set to 25 to 30 r / min, the pressure is set to 0.2 to 0.3 MPa, and after the double immersion and double squeezing, the fabric is placed in an oven for drying, and the drying temperature is set to 95 to 105°C.

5. The nylon digital printing process according to claim 1, characterized in that: The soap washing uses 1-2 g / L of standard soap flakes, a temperature of 90-100° C., and a washing time of 8-12 min. The water washing I is a cold water washing for 4-6 min, followed by a warm water washing at 35-45° C. for 4-6 min. The water washing II is a warm water washing at 35-45° C. for 4-6 min, followed by a cold water washing for 4-6 min. The bath ratios of the soap washing, water washing I, and water washing II are all 40:1-20:

1.

6. The nylon digital printing process according to claim 1, characterized in that: The inorganic salt is one or more of chloride, sulfate, acetate and carbonate.

7. The nylon digital printing process according to claim 1, characterized in that: The acidity regulator is one or more of acetic acid, hydrochloric acid, sulfuric acid and oxalic acid.

8. The nylon digital printing process according to claim 1, characterized in that: The monomer 1 is prepared by the following method: 1.0 eq of N-(tert-butyloxycarbonyl)ethanolamine, 1.5-2.0 eq of triethylamine, and 20 eq of anhydrous toluene are added to a three-necked flask; 1.5-2.0 eq of acryloyl chloride is dissolved in 20 eq of anhydrous toluene at a temperature of -10-5°C under an inert gas atmosphere, and then the mixture is slowly added to the three-necked flask using a syringe; the mixture is stirred and reacted at room temperature for 36-48 hours, filtered, and the obtained solution is concentrated, dissolved in dichloromethane, washed with a sodium hydroxide aqueous solution, and the organic phase is collected and dried by a rotary evaporator to obtain the monomer 1.

9. The nylon digital printing process according to claim 1, characterized in that: The monomer 2 is prepared by the following method: 1.0 eq of N-hydroxyethyl-2-pyrrolidone, 1.5-2.0 eq of triethylamine, and 20 eq of anhydrous toluene are added to a three-necked flask; 1.5-2.0 eq of acryloyl chloride is dissolved in 20 eq of anhydrous toluene at a temperature of -10-5°C under an inert gas atmosphere, and then the mixture is slowly added to the three-necked flask using a syringe; the mixture is stirred and reacted at room temperature for 36-48 hours, filtered, and the obtained solution is concentrated, dissolved in dichloromethane, washed with a sodium hydroxide aqueous solution, and the organic phase is collected and evaporated to dryness using a rotary evaporator to obtain monomer 2.

10. The nylon digital printing process according to claim 2, characterized in that: The hyperbranched initiator is prepared by the following method: 1 eq of hydroxyethyl acrylate, 1.5-2.0 eq of triethylamine and 40-50 eq of dichloromethane solvent are added to a three-necked flask, and 1.2-1.3 eq of 2-bromoisobutyryl bromide is slowly added dropwise to the three-necked flask at a temperature of -10-5°C under an inert gas atmosphere, and stirred at room temperature for 12-24 hours. After the reaction is completed, the mixture is washed with a saturated sodium bicarbonate solution and a saturated sodium chloride solution in sequence, dried with anhydrous magnesium sulfate, and then separated and purified with a silica gel column to obtain the hyperbranched initiator.

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