Textile pretreatment liquid and ink set for textile jet printing

Abstract

The invention provides a pretreatment liquid for textiles and an ink set for textile jet printing, and the pretreatment liquid comprises the following components in percentage by mass: 8%-15% of cationic polyurethane resin, 1%-3% of a cationic modified polyamine polymer and 3%-10% of nonionic isocyanate. Through component cooperation and functional complementation, the effect of the pretreatment liquid is improved, and the obtained textile is high in whiteness, good in hand feeling, free of cracking, high in washing fastness and good in printing fluency.

Description

Technical Field

[0001] This invention relates to the field of inkjet printing inks, specifically to a pretreatment solution for textiles and an ink set for inkjet printing textiles. Background Technology

[0002] Pure cotton fabrics, with their excellent softness, breathability, and skin-friendly comfort, are widely used in textile fields such as clothing and home decoration. In recent years, with the rapid development of digital printing technology and the increasing demand from consumers for personalized, high-precision textiles, digital direct-to-garment printing technology for pure cotton fabrics has become a research hotspot in the industry. However, traditional pigment inks are difficult to effectively adhere to pure cotton substrates, especially on pure cotton fabrics with a base color, thus limiting the application scenarios of pure cotton fabrics in the field of digital printing. To overcome these limitations, pretreatment technology has been introduced into the digital printing process. By applying a pretreatment liquid to the surface of pure cotton fabric, the wettability of the fiber surface is improved, the adhesion between the ink and the fabric is enhanced, and the white ink opacity, washability, and color fastness of the pattern are also improved. Currently, the digital direct-to-garment process using pretreatment liquid in conjunction with pigment inks has made some progress, but there are still many problems that need to be solved in the existing technology.

[0003] In existing technologies, some solutions disclose a pretreatment liquid whose components include cationic polyurethane dispersion, blocked isocyanate, organic acid, and metal salt. This liquid is applied to fabric via spraying or tie-dyeing, dried, and then printed with white and colored inks. While this approach attempts to improve ink adhesion through pretreatment, the process requires an additional drying step, resulting in low printing efficiency. Furthermore, the positioning accuracy between the pretreatment liquid and the pattern is insufficient, failing to meet the precise printing requirements of dyed fabrics. Additionally, the treated fabric has a stiffer hand feel, affecting the product's tactile experience.

[0004] Some existing technologies propose a pretreatment solution containing polyvalent metal salts, cationic polymers, high-boiling-point polyols, and water, which is then used for direct inkjet printing on fabric followed by immediate ink printing, thus improving process speed. However, this approach has several drawbacks: First, the polyvalent metal salts in the pretreatment solution can easily clog printheads and corrode printing equipment, increasing maintenance costs and affecting printing smoothness; second, polyvalent metal salts are water-soluble substances and are easily migrated and lost after washing, resulting in a significant decrease in the color fastness of the pattern; third, if the polyvalent metal salts are omitted and only the cationic polymer is retained, problems such as insufficient color development and ink bleeding may occur, failing to meet the requirements for pattern clarity.

[0005] In addition, existing technologies generally suffer from the following common problems: some pretreatment liquid formulations result in stiff fabrics, affecting wearing comfort; insufficient white ink coverage causes patterns to appear grayish on dark-colored fabrics; ink penetration is out of control, easily leading to bleeding or blurred edges; and some components have poor environmental friendliness (such as containing heavy metal salts), failing to meet green manufacturing requirements. These defects severely restrict the industrial application of digital direct-to-garment printing on pure cotton dyed fabrics, necessitating the development of a new pretreatment liquid and matching coating ink system that balances printing smoothness, pattern quality, color fastness, and environmental friendliness.

[0006] Therefore, in order to address the shortcomings of existing technologies, it is of great significance to develop a high-efficiency pretreatment liquid and matching coating ink suitable for pure cotton dyed fabrics, which can solve problems such as poor printing smoothness, insufficient color fastness, and stiff hand feel. Summary of the Invention

[0007] The first objective of this invention is to provide a pretreatment liquid for textiles that solves problems such as poor printing smoothness, insufficient color fastness, and stiff hand feel of existing pretreatment liquids.

[0008] A second objective of the present invention is to provide an ink set for textile printing, comprising the above-mentioned pretreatment liquid for textiles.

[0009] To achieve the first objective mentioned above, the present invention provides a pretreatment solution for textiles, which, by mass percentage, comprises 8% to 15% cationic polyurethane resin, 1% to 3% cationic modified polyamine polymer, and 3% to 10% nonionic isocyanate.

[0010] The pretreatment solution provided by this invention includes cationic polyurethane, cationic modified polyamine polymer, and nonionic isocyanate. The effect of the pretreatment solution is improved through component synergy and functional complementarity. The cationic polyurethane can combine with the dyed fabric to effectively improve fastness and form a film on the surface of the dyed fabric to prevent subsequent ink from penetrating into the fabric pores to improve color saturation and play a certain role in ink fixation. The cationic modified polyamine polymer has excellent ink fixation effect and wash fastness, and can work synergistically with the cationic polyurethane resin to strengthen pattern adhesion. Using a single component has limitations. For example, using cationic polyurethane resin alone results in a poor fabric feel, and its ink-fixing effect is insufficient. Using cationic modified polyamine polymer alone leads to poor printing smoothness and strong penetration of the pretreatment solution, and the white ink cannot effectively cover the base color of the dyed fabric. Through the synergistic effect of cationic polyurethane resin and cationic modified polyamine polymer, the hand feel problem and insufficient ink fixation of polyurethane resin alone are avoided, while the poor smoothness, excessive penetration, and white ink coverage defects of polyamine polymer alone are overcome. Ultimately, the pretreatment solution achieves excellent printing smoothness, high whiteness of the printed dyed fabric, high color fastness, and no bleeding. Furthermore, the addition of nonionic isocyanate forms a three-dimensional cross-linked network, further enhancing color fastness. At the same time, the pretreatment solution of this invention is highly efficient and easy to operate by spraying onto the surface of textiles. It does not contain polyvalent metal salts, avoiding the clogging of printheads and corrosion of printing equipment by polyvalent metal salts, thus reducing maintenance costs.

[0011] A further embodiment is that the cationic polyurethane is composed of a polyisocyanate and a polyol, wherein the side chain or main chain of the cationic polyurethane contains at least one of a quaternary ammonium group, a tertiary amine group that is partially or completely neutralized by an acid as a cationic center; the polyisocyanate is selected from at least one of aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates; and the polyol is selected from polyether polyols and / or polyester polyols.

[0012] Cationic polyurethane is prepared by reacting aliphatic, alicyclic or aromatic isocyanates with one or more of polyether polyols and polyester polyols. Quaternary ammonium groups or acid-neutralized tertiary amine groups are introduced into the side chain or main chain as cationic centers. This structural design makes it easy for the pretreatment solution to spread on the surface of the dyed fabric and form a continuous film.

[0013] A further option is that the polyisocyanate is selected from toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, tetramethyl-m-phenylenediamine diisocyanate, norbornene diisocyanate, and dimethylbiphenyl diisocyanate. The polyol is selected from at least one of esters and methylcyclohexyl diisocyanate; the polyol is selected from at least one of polyethylene glycol, polypropylene glycol, polytetramethyl glycol, polypropylene oxide glycol, polypropylene triol, glycerol adduct, triethanolamine adduct, pentaerythritol adduct, ethylenediamine adduct, diethylenetriamine adduct, adipic acid polyester diol, aromatic polyester polyol, aliphatic polyester polyol, polycaprolactone polyol, polycarbonate diol, and polyacrylate polyol.

[0014] The above components enable cationic polyurethane to easily spread into a uniform film on the surface of dyed fabric, and to tightly bind with fibers through polar groups. At the same time, it balances flexibility and rigidity, optimizes the compatibility of pretreatment solution and ink, and ultimately improves printing smoothness, pattern whiteness and color fastness, providing a more suitable functional basis for digital direct printing of pure cotton dyed fabric.

[0015] A further approach is to have a carbon chain as the main chain of the cationic modified polyamine polymer, and to have nitrogen-containing cationic groups in the side chains of the cationic modified polyamine polymer.

[0016] The main chain of the cationic modified polyamine polymer is a carbon chain, which gives it good flexibility and chemical stability, and it is easy to spread into a uniform film on the surface of dyed fabric. The nitrogen-containing cationic groups in the side chain (such as quaternary ammonium salts and tertiary amine salts) are tightly bound to the negatively charged sites on the fiber surface through electrostatic interaction, which enhances the ink adhesion.

[0017] A further option is that the cationic modified polyamine polymer is selected from at least one of cationic polymers such as methacrylate-type quaternary ammonium salts, acrylate-type quaternary ammonium salts, and allyl-type quaternary ammonium salts.

[0018] Cationic polymers such as methacrylate, acrylate, and allyl quaternary ammonium salts are selected as cationic modified polyamine polymers. Because their main chain is a carbon chain, they have good flexibility and film-forming properties, and are easy to spread on the surface of dyed fabrics. The side chains contain strong cationic groups (quaternary ammonium salts), which bind tightly to the fibers through electrostatic interaction, enhancing the ink's adhesion. The group density is controllable, balancing permeability and white ink coverage. At the same time, the reactivity is moderate, and the viscosity is stable when compounded with other components in the pretreatment solution, ensuring smooth printing and comprehensively improving color fastness, pattern clarity, and process applicability.

[0019] A further option is to include a surfactant in the pretreatment solution, wherein the surfactant is selected from nonionic surfactants.

[0020] Adding nonionic surfactants to the pretreatment solution ensures overall compatibility and stability because their uncharged nature prevents charge repulsion between the solution and components such as cationic polyurethane resin and cationic modified polyamine polymer. This reduces the surface tension of the pretreatment solution, improving its wetting and spreading properties on the dyed fabric surface and preventing droplet accumulation or uneven distribution. Simultaneously, it enhances film density, reduces defects such as pinholes, regulates ink penetration rate, balances ink fixation and diffusion, prevents bleeding or insufficient white ink coverage, and ultimately optimizes the bonding effect between the pretreatment solution and the fiber, providing a stable process foundation for high-definition, high-fastness pattern printing.

[0021] A further embodiment includes an organic solvent in the pretreatment solution, the organic solvent being selected from at least one of ethylene glycol, propylene glycol, glycerol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, and 2,2,4-trimethyl-1,3-pentanediol.

[0022] Adding polyol organic solvents such as ethylene glycol and glycerol to the pretreatment solution can adjust the solution viscosity and drying rate due to their good compatibility with the system, avoiding uneven film layer or nozzle clogging caused by excessively rapid drying. The hydrophilicity of polyols makes them highly compatible with pure cotton fibers, promoting the uniform spreading of the pretreatment solution. At the same time, they participate in the film formation process, enhancing the flexibility and adhesion of the film layer, preventing brittleness, and optimizing the interaction with cationic components to strengthen adhesion, thus comprehensively improving printing smoothness, pattern uniformity, and color fastness.

[0023] A further option is that, by mass percentage, the pretreatment solution comprises 8%–15% cationic polyurethane resin, 1%–3% cationic modified polyamine polymer, 3%–10% nonionic isocyanate, 20%–50% organic solvent, 0.5%–2% surfactant, 0.1%–0.5% additives, and the balance being water.

[0024] The above ratio avoids the following: if the content of cationic polyurethane resin is too high, it will result in a poor hand feel of the fabric and may even cause cracking in severe cases; if the content is too low, it will not be able to effectively form a resin film on the fabric surface, allowing the ink to penetrate into the fabric mesh and resulting in insufficient white ink coverage; if the content of cationic polymer is too high, it will affect the stability of the pretreatment solution, while if it is too low, it will cause problems such as poor fastness. Therefore, the components are used in combination to achieve high fastness, good hand feel, and without affecting the smoothness of inkjet printing.

[0025] To achieve the second objective mentioned above, the present invention provides an ink set for textile inkjet printing, the ink set comprising a textile pretreatment liquid and a coating ink as described in any of the above embodiments.

[0026] The above-mentioned pretreatment solution is well compatible with existing coatings and inks and has wide applicability.

[0027] A further option is that the coating ink includes anionic resin, anionic crosslinking agent, and color paste; the anionic resin is selected from anionic polyurethane resin; and the anionic crosslinking agent is selected from anionic isocyanate.

[0028] The coating ink uses anionic polyurethane resin and anionic isocyanate. Anionic polyurethane provides good film-forming and adhesion properties, ensuring that the ink is fixed on the fabric surface. Anionic isocyanate enhances the density of the film layer through cross-linking reaction and improves wash fastness. The anionic properties of both and the cationic components of the pretreatment solution work synergistically to promote the directional binding of the ink, reduce bleeding, and ensure clear patterns and color fastness. Detailed Implementation

[0029] This invention provides a pretreatment solution for textiles, comprising, by mass percentage, 8%–15% cationic polyurethane resin, 1%–3% cationic modified polyamine polymer, 3%–10% nonionic isocyanate, 20%–50% organic solvent, 0.5%–2% surfactant, 0.1%–0.5% auxiliaries, and the balance being water. Preferably, the ratio of cationic polyurethane resin to nonionic isocyanate is 1:1 to 5:1, more preferably 4:1. If the proportion of nonionic isocyanate is too low, it cannot provide sufficient crosslinking points for film formation; if the proportion of nonionic isocyanate is too high, it will result in a poor hand feel.

[0030] Cationic polyurethane resins are composed of polyisocyanates and polyols. The side chains or main chains of cationic polyurethanes contain at least one of the following as cationic centers: quaternary ammonium groups, tertiary amine groups partially or completely neutralized by acid. The polyisocyanate is selected from at least one of aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates. The polyol is selected from polyether polyols and / or polyester polyols. The polyisocyanate is selected from toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, tetramethyl-m-phenylenediamine diisocyanate, norbornene diisocyanate, dimethyl biphenyl diisocyanate, and so on. At least one of cyclohexyl diisocyanate; the polyol is selected from at least one of polyethylene glycol, polypropylene glycol, polytetramethyl glycol, polypropylene oxide glycol, polypropylene triol, glycerol adduct, trimethylolpropane adduct, pentaerythritol adduct, ethylenediamine adduct, diethylenetriamine adduct, adipic acid polyester diol, aromatic polyester polyol, aliphatic polyester polyol, polycaprolactone polyol, polycarbonate diol, and polyacrylate polyol. Specifically, it can be selected from Delt DT-8119, DT-8229, Guangzhou Gaotai W-801, and Beijing Zhuoyue Dongfang Technology CFD-36.

[0031] The main chain of the cationic modified polyamine polymer is a carbon chain, and the side chains of the cationic modified polyamine polymer contain nitrogen-containing cationic groups, such as quaternary ammonium salts, primary amines, secondary amines, or tertiary amine salts. Specifically, the cationic modified polyamine polymer can be selected from at least one of cationic polymers such as methacrylate-type quaternary ammonium salts, acrylate-type quaternary ammonium salts, and allyl-type quaternary ammonium salts. More preferably, it is diallyl dimethyl ammonium chloride polymer, poly(trimethylaminoethyl methacrylate) methyl sulfate, and diallyl dimethyl ammonium chloride acrylamide copolymer. Specifically, it can be selected from Yoshikawa Chemical Industry Co., Ltd.'s LJC-D10, LJC-D208, LJC-EC12, LJC-EC210, LJC-CA530, and LJO-X50N.

[0032] Nonionic isocyanates can be specifically selected from Delta DT-821 and Covestro IMPRAFIX IO3094.

[0033] The surfactant is selected from nonionic surfactants. Preferably, it is an acetylenol surfactant and / or a polyoxyethylene ether surfactant. Specifically, it can be selected from Air Chemical Surfynol 465, Surfynol 485, Kao EMULGEN 1108, EMULGEN LS-110, and EMULGEN LS-114.

[0034] The organic solvent is selected from the polyol series, specifically from at least one of ethylene glycol, propylene glycol, glycerol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, and 2,2,4-trimethyl-1,3-pentanediol. Glycerol and ethylene glycol are preferred.

[0035] The adjuvant can be a bactericide; any commercially available bactericide will suffice.

[0036] The pretreatment solution is prepared by adding 8%~15% cationic polyurethane resin, 1%~3% cationic modified polyamine polymer, 3%~10% nonionic isocyanate, 20%~50% organic solvent, 0.5%~2% surfactant, 0.1%~0.5% additives, and the balance water into a mixing tank, stirring evenly, and then filtering twice through a Kebaite 0.45pp filter membrane.

[0037] The present invention also provides an ink set for textile inkjet printing, the ink set comprising the above-mentioned textile pretreatment liquid and coating ink.

[0038] The paint ink can be commercially available paint ink or homemade paint ink as described below.

[0039] By weight percentage, homemade paint inks consist of 10%–20% color paste, 10%–20% anionic polyurethane resin, 1%–3% anionic crosslinking agent, 20%–50% organic solvent, 0.5%–2% surfactant, 0.1%–0.5% bactericide, and the balance being water. The total amount of anionic polyurethane resin should not exceed 50% of the total amount of homemade paint inks, and preferably should not exceed 30%. Too low a amount will not provide sufficient fastness, while too high a amount will result in a poor fabric feel.

[0040] The color pastes are commercially available color pastes, specifically selected from Shanghai Yunling self-dispersing color pastes: K500, C500, M500, and Y500.

[0041] Anionic polyurethane resins can be selected from Mitsui Chemicals W6110 and Matsui Chemicals resin-T.

[0042] The anionic crosslinking agent is anionic isocyanate, specifically Covestro Imprafix® 2794.

[0043] The organic solvent is a polyol series, and can be selected from at least one of ethylene glycol, propylene glycol, glycerol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, and 2,2,4-trimethyl-1,3-pentanediol. Glycerol and ethylene glycol are preferred.

[0044] The surfactant is selected from nonionic surfactants, preferably acetylenic diol surfactants and polyoxyethylene ether surfactants. Specifically, it can be selected from Surfynol 465, Surfynol 485, Kao EMULGEN 1108, EMULGEN LS-110, and EMULGEN LS-114.

[0045] The method for preparing homemade paint ink is as follows: Add 20%~50% organic solvent, 0.5%~2% surfactant, 0.1%~0.5% bactericide and the balance water to a mixing tank and stir evenly. Then add 10%~20% anionic polyurethane resin and 1%~3% anionic crosslinking agent and continue stirring until the solution becomes clear and transparent. Finally, add 10%~20% color paste, stir evenly, and filter twice with a Kebaite 0.45pp filter membrane.

[0046] The following detailed description of the solution is provided in conjunction with specific embodiments.

[0047] Preparation of pretreatment solution Prepare the pretreatment solution according to the component contents in Tables 1 and 2.

[0048] Table 1

[0049] Table 2

[0050] Preparation of paint inks: White ink: Add 10% glycerin, 20% ethylene glycol, 0.5% Surfynol 465, 0.1% bactericide and 26.4% water to a mixing tank and stir well. Then add 20% W6110 and 3% Imprafix® 2794 and continue stirring until the solution becomes clear and transparent. Finally, add 20% white pigment, stir well and filter twice through a Corbett 0.45pp filter membrane.

[0051] Black ink: Add 10% glycerin, 20% ethylene glycol, 0.5% Surfynol 465, 0.1% bactericide and 26.4% water to a mixing tank and stir well. Then add 20% W6110 and 3% Imprafix® 2794 and continue stirring until the solution becomes clear and transparent. Finally, add 20% black pigment, stir well and filter twice through a Corbett 0.45pp filter membrane.

[0052] Blue ink: Add 10% glycerin, 20% ethylene glycol, 0.5% Surfynol 465, 0.1% bactericide and 26.4% water to a mixing tank and stir well. Then add 20% W6110 and 3% Imprafix® 2794 and continue stirring until the solution becomes clear and transparent. Finally, add 20% blue pigment, stir well and filter twice through a Corbett 0.45pp filter membrane.

[0053] Magenta ink: Add 10% glycerin, 20% ethylene glycol, 0.5% surfynol 465, 0.1% bactericide and 26.4% water to a mixing tank and stir well. Then add 20% W6110 and 5% Imprafix® 2794 and continue stirring until the solution becomes clear and transparent. Finally, add 20% magenta pigment, stir well and filter twice through a Corbett 0.45pp filter membrane.

[0054] Yellow ink: Add 10% glycerin, 20% ethylene glycol, 0.5% Surfynol 465, 0.1% bactericide and 26.4% water to a mixing tank and stir well. Then add 30% W6110 and 10% Imprafix® 2794 and continue stirring until the solution becomes clear and transparent. Finally, add 20% yellow pigment, stir well and filter twice through a Corbett 0.45pp filter membrane.

[0055] Application methods Simply load the pure cotton dyed fabric directly into the pretreatment solution for printing, white ink, and color ink, and dry at 150℃ for 5 minutes.

[0056] Performance tests were conducted on the pure cotton dyed fabric after printing with the above pretreatment solution and pigment ink: 1. Whiteness: An evaluation panel of 3-5 or more trained or sensory-sensitive individuals will lay the printed sample flat and observe the color uniformity of the white area of ​​the sample under uniform natural light. The evaluation result with the most participants will be the final evaluation result.

[0057] Evaluation criteria: Whiteness A: Not transparent to the background, Whiteness B: Slightly transparent to the background, Whiteness C: Severely transparent to the background.

[0058] 2. Cracking: An evaluation team of 3-5 or more trained or sensory-sensitive individuals will lay the printed sample flat and observe its surface condition under uniform natural light. The evaluation result with the most participants will be the final evaluation result.

[0059] Evaluation criteria: Crack A: No cracks, Crack B: Cracks present, Crack C: Too many cracks.

[0060] 3. Hand feel: An evaluation team of 3-5 or more trained or sensory-sensitive individuals will lay the printed sample flat and gently slide their fingertips back and forth on the sample surface to feel the hardness of the sample surface. The evaluation result with the most participants will be the final evaluation result.

[0061] Evaluation criteria: Feel A: No change in feel; Feel B: Significantly harder; Feel C: Very hard.

[0062] 4. Fastness: Place the sample in a washing machine connected to water and electricity, add 50g of laundry detergent according to household washing instructions, set the washing mode, and wash for a total of 90 minutes. After washing, allow the sample to air dry naturally at room temperature. Record any instances of cracking or detachment of the sample after several washes.

[0063] Evaluation criteria: Fastness A: No problem after 10 washes; Fastness B: Color fades after 5 washes; Fastness C: Color fades after 1 wash.

[0064] 5. Bleeding: Print high-concentration colors (such as black, dark blue, magenta) closely adjacent to light-colored (white and yellow) patches. An evaluation panel of 3-5 or more trained or sensory-sensitive people observes whether the boundary lines of the intersections between different colors in the printed pattern are clear.

[0065] Evaluation criteria: Bleeding A: Clear boundaries visible to the naked eye; Bleeding B: Slight color diffusion visible to the naked eye, with slightly blurred boundaries; Bleeding C: Obvious bleeding visible to the naked eye, with blurred boundaries.

[0066] 6. Printing smoothness: After printing 300 meters continuously at 100% ink volume, test the mesh status.

[0067] Evaluation criteria: A: Number of broken holes < 3, B: Number of broken holes 3-5, C: Number of broken holes > 5.

[0068] The test results are shown in Table 3 below.

[0069] Table 3

[0070] As shown in Tables 1 to 3 above, in Comparative Examples 1 and 2, the amount of cationic polyurethane resin added was low, resulting in poor performance of the printed pure cotton dyed fabric in terms of whiteness, wash fastness, and color bleeding. In Comparative Example 3, the amount of cationic polyurethane resin added was low but higher than that in Comparative Examples 1 and 2. Although the whiteness and color bleeding of the printed pure cotton dyed fabric were improved, the wash fastness was still poor. In Comparative Example 4, the amount of cationic polyurethane resin added was high, resulting in poor cracking, hand feel, and printing smoothness of the printed pure cotton dyed fabric, and the whiteness, fastness, and color bleeding were also average. In Comparative Example 5, no cationic polyurethane resin was added, resulting in cracking and poor performance of the printed pure cotton dyed fabric in terms of whiteness and color bleeding. In Comparative Example 6, the amount of cationic modified polyamine polymer added was low, resulting in poor performance of the printed pure cotton dyed fabric in terms of wash fastness and color bleeding, with cracks present, and the whiteness, hand feel, and printing smoothness were also average. In Comparative Example 7, the amount of cationic modified polyamine polymer added was low, resulting in poor performance of the printed pure cotton dyed fabric in terms of wash fastness and color bleeding, with cracks present, and the whiteness, hand feel, and printing smoothness were also average. The addition of a large amount of cationic modified polyamine polymer resulted in poor printing smoothness of the printed cotton dyed fabric, and its performance in whiteness, wash fastness, and bleeding was also mediocre. Comparative Example 8, which did not add cationic modified polyamine polymer, resulted in cracking of the printed cotton dyed fabric, and its performance in hand feel, bleeding, fastness, and printing smoothness was also poor. Comparative Example 9, which used metal salt, resulted in poor whiteness, wash fastness, bleeding, and printing smoothness of the printed cotton dyed fabric. Comparative Examples 10 and 11, with excessive amounts of nonionic isocyanate, resulted in poor hand feel and printing smoothness of the printed cotton dyed fabric. Comparative Example 12, with insufficient amounts of nonionic isocyanate, resulted in poor wash fastness of the printed cotton dyed fabric, and its performance in whiteness and bleeding was also mediocre. Comparative Example 13, without the addition of nonionic isocyanate, resulted in poor whiteness and wash fastness of the printed cotton dyed fabric, and its performance in bleeding was also mediocre. The pure cotton dyed fabric obtained by using the pretreatment solution corresponding to the embodiment of the present invention has higher whiteness, better hand feel, no cracking, higher wash fastness, and better printing smoothness compared with the comparative example.

[0071] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A pretreatment solution for textiles, characterized in that: The pretreatment solution comprises, by weight percentage, 8% to 15% cationic polyurethane resin, 1% to 3% cationic modified polyamine polymer and 3% to 10% nonionic isocyanate.

2. The pretreatment solution for textiles as described in claim 1, characterized in that: The cationic polyurethane is composed of polyisocyanate and polyol, and the side chain or main chain of the cationic polyurethane contains at least one of quaternary ammonium group, tertiary amine group that is partially or completely neutralized by acid as a cationic center. The polyisocyanate is selected from at least one of aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates; The polyol is selected from polyether polyols and / or polyester polyols.

3. The pretreatment solution for textiles as described in claim 2, characterized in that: The polyisocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, phenylmethylene diisocyanate, cyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, tetramethyl-m-phenylmethylene diisocyanate, norbornane diisocyanate, dimethyl biphenyl diisocyanate, and methylcyclohexyl diisocyanate. The polyol is selected from at least one of polyethylene glycol, polypropylene glycol, polytetramethyl glycol, polypropylene oxide glycol, polypropylene triol, glycerol adduct, triethanolamine adduct, pentaerythritol adduct, ethylenediamine adduct, diethylenetriamine adduct, adipic acid polyester diol, aromatic polyester polyol, aliphatic polyester polyol, polycaprolactone polyol, polycarbonate diol, and polyacrylate polyol.

4. The pretreatment solution for textiles as described in claim 1, characterized in that: The main chain of the cationic modified polyamine polymer is a carbon chain, and the side chains of the cationic modified polyamine polymer contain nitrogen-containing cationic groups.

5. The pretreatment solution for textiles as described in claim 4, characterized in that: The cationic modified polyamine polymer is selected from at least one of cationic polymers such as methacrylate quaternary ammonium salts, acrylate quaternary ammonium salts, and allyl quaternary ammonium salts.

6. A pretreatment solution for textiles as described in any one of claims 1 to 5, characterized in that: The pretreatment solution also includes a surfactant, which is selected from nonionic surfactants.

7. A pretreatment solution for textiles as described in any one of claims 1 to 5, characterized in that: The pretreatment solution further includes an organic solvent selected from at least one of ethylene glycol, propylene glycol, glycerol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, and 2,2,4-trimethyl-1,3-pentanediol.

8. A pretreatment solution for textiles as described in any one of claims 1 to 5, characterized in that: The pretreatment solution comprises, by weight percentage, 8% to 15% of the cationic polyurethane resin, 1% to 3% of the cationic modified polyamine polymer, 3% to 10% of the nonionic isocyanate, 20% to 50% of the organic solvent, 0.5% to 2% of the surfactant, 0.1% to 0.5% of the additives, and the balance being water.

9. An ink set for textile inkjet printing, characterized in that: The ink group includes a textile pretreatment liquid and a coating ink as described in any one of claims 1 to 8.

10. The ink set for textile inkjet printing according to claim 9, characterized in that: The coating ink includes anionic resin, anionic crosslinking agent, and color paste; The anion exchange resin is selected from anion exchange polyurethane resin; The anionic crosslinking agent is selected from anionic isocyanates.

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