Preparation method and application of waterborne polyurethane resin for bottoming treatment of printed fabric

Abstract

The invention relates to the field of functional coatings, and particularly discloses a preparation method and application of waterborne polyurethane resin for bottoming treatment of printed fabric. Waterborne polyurethane resin for bottoming treatment of printed fabric is mainly prepared through reaction of polyester polyol A, polyester polyol B, polyethylene glycol and diisocyanate monomers, Mn of the polyester polyol A is 2000, and Mn of the polyester polyol B is 3000. The product provided by the invention can be blended with auxiliaries such as a wetting agent, a flatting agent, a defoaming agent and a thickening agent to obtain a bottoming treatment agent with a thermal activation characteristic, a bottoming treatment agent coating formed by printing, heating and drying the bottoming treatment agent can form a good bonding interface with a fabric with low surface energy, and the bonding fastness between the interfaces is not lower than 3.5 kgf / cm; therefore, the effects of anchoring the fabric and fixing the printing layer can be achieved, and the bonding firmness between the fabric and the printing layer is improved.

Description

Technical Field

[0001] This application relates to the technical field of functional coatings, and particularly to a preparation method and application of a waterborne polyurethane resin for primer treatment of printed fabrics. Background Art

[0002] Sports shoe fabrics are mainly made of various raw materials such as spandex, polyester, TPE, TPEE, and high-elastic nylon, which belong to synthetic fibers and have the advantages of high strength, fold resistance, good tear resistance, lightness, comfort, and breathability. For the aesthetics of the shoe upper and brand recognition, manufacturers often print colored patterns with a certain thickness on the fabric of the shoe upper by using multiple layers of printed waterborne printing pastes and baking and film-forming.

[0003] In order to meet the requirements of waterproofing and stain resistance, some fabrics will be pre-treated with waterproofing and anti-fouling on the fabric surface; or for cost reduction and waste material recycling considerations, some fabrics use recycled waste such as plastic bottles for reprocessing and recombining with other fibers. These practices will result in fabrics having a low surface energy, being incompatible with waterborne printing pastes, and having poor adhesion fastness, thus causing the printed layer to fail to reach the required bonding fastness. To solve the above problems, it is necessary to perform primer treatment on the fabric before printing, that is, to coat an adhesion promoter (also known as a primer treatment agent) on the fabric surface. This material can anchor the fabric and also has good bonding fastness to the printed layer, effectively solving the problem of poor printing fastness.

[0004] As a high-cohesive energy polymer with strong polar groups (urethane groups), polyurethane resin theoretically has a very high adhesion fastness to fabrics and is a preferred base material for primer treatment agents. At present, the primer treatment agents on the market are mainly organic solvent-based materials, that is, through the permeability of solvents and baking curing, the bonding fastness between the primer treatment agent and the fabric is improved. However, a large amount of organic solvents in the organic solvent-based polyurethane resin composition do not meet the requirements of environmental protection and low toxicity, so it is not suitable for widespread use. The solvent of waterborne polyurethane resin is water, which avoids the occurrence of many drawbacks caused by the use of organic solvents. However, since it uses water as the dispersion medium and the polyurethane resin in the system is also waterborne, the surface energy is relatively large, and there is a large difference in surface energy between the waterborne primer treatment agent and the fabric, so a good bonding interface cannot be formed between the waterborne primer treatment agent and the fabric, which greatly affects the bonding fastness. Summary of the Invention

[0005] To solve the above technical problems, this application provides a preparation method and application of a waterborne polyurethane resin for primer treatment of printed fabrics.

[0006] In the first aspect, this application provides a preparation method of a waterborne polyurethane resin for primer treatment of printed fabrics, including the following steps: S1. Mix polyester polyol A, polyester polyol B and polyethylene glycol with a weight ratio of (120 - 160):(35 - 45):(4 - 6), heat up and dehydrate under vacuum conditions, then cool down, add diisocyanate monomer, stir, heat up to 90 - 110 °C and keep the temperature for reaction for 2 - 3 h, cool down to 70 - 90 °C, add a catalyst and continue the reaction for 2 - 3 h, add a solvent and then cool down to obtain an intermediate product. The Mn of the polyester polyol A is 2000, and it includes one or more of adipic acid - ethylene glycol polyester polyol, adipic acid - 1,4 - butanediol polyester polyol and adipic acid - 1,6 - hexanediol polyester polyol. The Mn of the polyester polyol B is 3000, and it includes one or more of adipic acid - ethylene glycol polyester polyol, adipic acid - 1,4 - butanediol polyester polyol and adipic acid - 1,6 - hexanediol polyester polyol. The catalyst includes one or more of organic bismuth, organic tin T9 and organic tin T12; S2. Add chain extender A to the intermediate product obtained in step S1, stir at a speed of 80 - 100 rpm for 15 - 20 min, then add water for dilution and stir at a speed of 1200 - 1400 rpm for 5 - 10 min, add chain extender B, stir for 10 - 15 min and then adjust the speed to 60 - 80 rpm, heat up and reduce pressure until the mass in the system is constant to obtain a waterborne polyurethane resin. The chain extender B includes one or more of ethylenediamine, 1,2 - propanediamine, 1,6 - hexanediamine, isophorone diamine and hydroxyethyl ethylenediamine.

[0007] By adopting the above technical solution, in this application, polyester polyols with different molecular weights are blended with polyethylene glycol, and diisocyanate monomer is added to carry out a polymerization reaction under certain conditions, and then chain extension treatment is carried out. At the same time, the dosage ratios between various substances are also controlled in this application. Finally, a waterborne polyurethane resin with excellent thermal activation characteristics is prepared, which has a melting property at a specific melting temperature, and fully penetrates into the fabric fiber structure, and then through curing and forming, a good biting effect is generated with the fibers, and finally a firm and stable primer coating is formed, so that the adhesion effect of the waterborne printing paste is significantly improved, the combination between the printing layer and the fabric is stable and not easy to fall off, and the quality of the shoes is improved.

[0008] Moreover, in this application, one or more of organic bismuth, organic tin T9 and organic tin T12 are used as catalysts, which can effectively promote the reaction process of polyester polyol and diisocyanate monomer, and ensure the generation of prepolymer within a short time. At the same time, the selection of these catalysts can also improve the molecular weight distribution uniformity of the final waterborne polyurethane resin. Specifically, organic bismuth - based catalysts help to reduce the occurrence of side reactions and improve the purity of the product; organic tin T9 and T12 can catalyze the reaction at a lower temperature, which is beneficial to controlling the heat release during the reaction process and inhibiting the degradation process of the product caused by high temperature.

[0009] Preferably, in step S1, polyester polyol A is adipic acid-1,4-butanediol polyester polyol.

[0010] Preferably, in step S1, the polyester polyol B is adipic acid-1,6-hexanediol polyester polyol.

[0011] Preferably, in step S1, the catalyst is organic bismuth.

[0012] Preferably, in step S2, the chain extender B is hydroxyethylethylenediamine.

[0013] By adopting the above technical scheme, the present application further optimizes the types of raw materials and further improves the thermal activation properties of the water-based polyurethane resin, which can more fully penetrate into the fiber tissue of the fabric at a certain temperature, so that the adhesion effect of the water-based printing paste is further improved. Experimental data show that the bonding strength between the fabric and the printing layer is significantly improved at this time.

[0014] Preferably, in step S1, the polyethylene glycol includes one or more of PEG-1000, PEG-2000 and PEG-3000.

[0015] By adopting the above technical solution, the present application utilizes polyethylene glycol with a suitable molecular weight as a raw material, which significantly improves the thermal activation characteristics and penetration ability of the waterborne polyurethane resin.

[0016] Preferably, in the step S1, the diisocyanate monomer includes hexamethylene diisocyanate and / or isophorone diisocyanate.

[0017] By adopting the above-mentioned technical scheme, the present application utilizes a specific type of diisocyanate monomer to significantly optimize the molecular structure characteristics of the waterborne polyurethane resin, which helps to enhance the internal crosslinking density of the resin, and can also provide better mechanical properties in subsequent applications, showing higher adaptability and stronger durability.

[0018] In a second aspect, the present application provides an aqueous polyurethane resin for base treatment of printed fabrics prepared by the above-mentioned preparation method.

[0019] By adopting the above technical scheme, the water-based polyurethane resin of the present application has a thermal activation property. The water-based polyurethane resin has a thermal activation property and can fully penetrate into the fibers of the fabric at a specific melting temperature to form a good bite effect with the fibers, thereby greatly improving the bonding strength between the difficult-to-attach fabric and the printing layer.

[0020] In a third aspect, the present application provides a primer treatment agent, which is prepared by the following method: blending the aqueous polyurethane resin with other additives until the viscosity of the system reaches 90000-110000 CPS, thus obtaining the primer treatment agent.

[0021] Preferably, the raw materials used include the following components in parts by weight: 95.0-96.0 parts of aqueous polyurethane resin; 0.3-0.5 part of wetting agent; 0.2-0.4 part of leveling agent; 0.2-0.4 part of defoaming agent; 1.5-2.0 parts of thickening agent; 1.0-3.0 parts of water.

[0022] By adopting the above technical solution, the primer treatment agent of the present application, through the reasonable compatibility of the aqueous polyurethane resin and the additives and adjusting the viscosity of the system to an appropriate range, can effectively infiltrate and penetrate the fabric when applied to the printed fabric, thereby enhancing the mechanical interlocking ability between the treatment agent and the fabric, and also optimizing the spreading property and bonding strength of the subsequent printed layer thereon, thus effectively improving the stability of the overall structure. In addition, this method avoids the environmental burden that may be brought by traditional solvent-based materials, and has both high efficiency and environmental protection advantages.

[0023] In summary, the present application has the following beneficial technical effects: 1. The preparation method of the present application blends polyester polyols with different molecular weights and polyethylene glycol, and adds diisocyanate monomers, and through polymerization, chain extension and functionalization steps under certain conditions, while controlling the dosage ratio between various substances, an aqueous polyurethane resin with excellent thermal activation characteristics is prepared; 2. The aqueous polyurethane resin of the present application has thermal activation characteristics and can fully penetrate into the interior of the fabric fibers at a specific melting temperature, forming a good biting effect with the fibers, thereby greatly improving the adhesion fastness between the difficult-to-adhere fabric and the printed layer; 3. The primer treatment agent of the present application can effectively infiltrate and penetrate the fabric, thereby enhancing the mechanical interlocking ability between the primer treatment agent and the fabric, and also optimizing the spreading property and bonding strength of the subsequent printed layer thereon, thus effectively improving the stability of the overall structure. Specific Embodiments

[0024] Source of Materials Unless otherwise specified, the raw materials used in the present application are all commercially available products, specifically: Polyethylene adipate glycol was purchased from Shanghai Huide Technology Co., Ltd., with the brand name HDPOL-2220D and a molecular weight of 2000; Polybutylene adipate was purchased from Shanghai Huide Technology Co., Ltd., with the brand name HDPOL-4420D and a molecular weight of 2000; Poly(1,6-hexanediol adipate) was purchased from Shanghai Huide Technology Co., Ltd., with the trade name HDPOL-6620D and a molecular weight of 2000; Poly(ethylene glycol adipate) was purchased from Shanghai Huide Technology Co., Ltd., with the trade name HDPOL-2230J and a molecular weight of 3000; Poly(1,4-butanediol adipate) was purchased from Shanghai Huide Technology Co., Ltd., with the trade name HDPOL-4430J and a molecular weight of 3000; Poly(1,6-hexanediol adipate) was purchased from Shanghai Huide Technology Co., Ltd., with the trade name HDPPOL-6630J and a molecular weight of 3000; Isophorone diisocyanate was purchased from Covestro Polymer Co., Ltd., with a molecular weight of 222.28; 1,6-Hexamethylene diisocyanate was purchased from Covestro Polymer Co., Ltd., with a molecular weight of 168.19; Polyethylene glycol PEG-1000 was purchased from BASF, with a molecular weight of 1000; Polyethylene glycol PEG-2000 was purchased from BASF, with a molecular weight of 2000; Polyethylene glycol PEG-3000 was purchased from BASF, with a molecular weight of 3000; Sodium N-(2-aminoethyl)-2-aminoethanesulfonate was purchased from Shanghai Kayin Chemical Co., Ltd., with the trade name A-95, a molecular weight of 190, and was in a 50 wt% solution state; N-(2-hydroxyethyl)ethylenediamine was purchased from Shanghai Kayin Chemical Co., Ltd., with a molecular weight of 104.15; 1,2-Propanediamine was purchased from Shandong Yinglang Chemical Co., Ltd., with a molecular weight of 74.12; 1,6-Hexanediamine was purchased from Shandong Yinglang Chemical Co., Ltd., with a molecular weight of 116.21; Organotin T9 catalyst was purchased from Shandong Maofa Chemical Co., Ltd.; Organotin T12 catalyst was purchased from Shandong Maofa Chemical Co., Ltd.; Organobismuth catalyst was purchased from Shanghai Deyin Chemical Co., Ltd.; The wetting agent was purchased from Degussa Additives GmbH, with the trade name TEGO Foamex-810, which is a polyether siloxane copolymer containing fumed silica; The leveling agent was purchased from BYK-Chemie GmbH, with the trade name BYK-333 and a density (20 °C) of 1.04 g / mL; The defoaming agent was purchased from Chongqing Compe Chemical Industry Co., Ltd., with the trade name PE-100, an active ingredient of 83 - 87%, and a density of 0.91 - 1.03 g / cm 3 ; The associative thickener was purchased from Borchers Chemie GmbH, with the trade name Borchi Gel-0434 and a density of 1.01 - 1.05 g / cm 3, the maximum viscosity is 15,000 mPa·s, and the non-volatile content is 19 - 21%.

[0025] The following further elaborates on this application in conjunction with examples.

[0026] Example 1 A preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics, comprising the following steps: S1. Blend 120 g of adipic acid-ethylene glycol polyester polyol (Mn = 2000), 45 g of adipic acid-1,4-butanediol polyester polyol (Mn = 3000), and 4 g of PEG-1000, heat up to 125 ± 2 °C, and dehydrate for 1 h under the condition of vacuum degree > 0.095 MPa. Then cool down to below 60 °C, add 25 g of 1,6-hexamethylene diisocyanate and 25 g of isophorone diisocyanate, stir for 10 min, heat up to 110 °C and keep the reaction for 2 h, cool down to 90 °C, add 0.1 g of organotin T12 catalyst and continue the reaction for 2 h. Stop heating, add 550 g of acetone and slowly cool down to below 40 °C to obtain an intermediate product; S2. Add 4 g of chain extender A (sodium ethylenediamine ethanesulfonate A-95) to all the intermediate products obtained in step S1, stir at a speed of 100 rpm for 15 min, then increase the speed, add 300 g of water for dilution and stir for 5 min at a speed of 1400 rpm, dropwise add 2 g of chain extender B (1 g of isophorone diamine and 1 g of ethylenediamine), stir for 15 min and then adjust the speed to 60 rpm, heat up to 55 °C, and remove acetone under reduced pressure until the mass in the system is constant to obtain the aqueous polyurethane resin.

[0027] Example 2 A preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics, comprising the following steps: S1. Blend 160 g of adipic acid-1,6-hexanediol polyester polyol (Mn = 2000), 35 g of adipic acid-ethylene glycol polyester polyol (Mn = 3000), and 5 g of PEG-3000, heat up to 125 ± 2 °C, and dehydrate for 1 h under the condition of vacuum degree > 0.095 MPa. Then cool down to below 60 °C, add 20 g of 1,6-hexamethylene diisocyanate, stir for 10 min, heat up to 90 °C and keep the reaction for 3 h, cool down to 70 °C, add 0.2 g of organotin T9 catalyst and continue the reaction for 3 h. Stop heating, add 450 g of acetone and slowly cool down to below 40 °C to obtain an intermediate product; S2. Add 6 g of chain extender A (sodium ethylenediamine ethanesulfonate A-95) to all the intermediate products obtained in step S1, stir for 20 min at a rotation speed of 80 rpm, then increase the rotation speed, add 250 g of water for dilution and stir for 10 min at a rotation speed of 1200 rpm, dropwise add 4 g of chain extender B (2 g of 1,2-propanediamine and 2 g of 1,6-hexanediamine), adjust the rotation speed to 80 rpm after stirring for 10 min, raise the temperature to 55 °C, and remove acetone under reduced pressure until the mass in the system is constant to obtain the aqueous polyurethane resin.

[0028] Example 3 A preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics, comprising the following steps: S1. Blend 140 g of adipic acid-1,4-butanediol polyester polyol (Mn = 2000), 40 g of adipic acid-1,6-hexanediol polyester polyol (Mn = 3000) and 4.5 g of PEG-2000, raise the temperature to 125 ± 2 °C, and dehydrate for 1 h under the condition of vacuum degree > 0.095 MPa, then cool down to below 60 °C, add 35 g of isophorone diisocyanate, stir for 10 min, raise the temperature to 100 °C and keep the temperature for reaction for 2.5 h, cool down to 80 °C, add 0.15 g of organic bismuth catalyst and continue the reaction for 2.5 h, stop heating, add 500 g of acetone and slowly cool down to below 40 °C to obtain the intermediate product; S2. Add 5 g of chain extender A (sodium ethylenediamine ethanesulfonate A-95) to all the intermediate products obtained in step S1, stir for 18 min at a rotation speed of 90 rpm, then increase the rotation speed, add 275 g of water for dilution and stir for 12 min at a rotation speed of 1300 rpm, dropwise add 3 g of chain extender B (hydroxyethyl ethylenediamine), adjust the rotation speed to 70 rpm after stirring for 12 min, raise the temperature to 55 °C, and remove acetone under reduced pressure until the mass in the system is constant to obtain the aqueous polyurethane resin.

[0029] Application Example 1 A primer treatment agent is prepared by the following method: Blend 950 g of the aqueous polyurethane resin obtained in Example 1 with 3 g of wetting agent, 4 g of leveling agent, 2 g of defoaming agent, 20 g of associative thickener and 10 g of deionized water, and adjust the viscosity of the system to reach 110000 CPS to obtain the primer treatment agent.

[0030] Application Example 2 A primer treatment agent is prepared by the following method: Blend 960 g of the aqueous polyurethane resin obtained in Example 2 with 5 g of wetting agent, 2 g of leveling agent, 4 g of defoaming agent, 15 g of associative thickener and 30 g of deionized water, and adjust the viscosity of the system to reach 90000 CPS to obtain the primer treatment agent.

[0031] Application Example 3 A primer treatment agent is prepared by the following method: 955 g of the aqueous polyurethane resin obtained in Example 3, 4 g of a wetting agent, 3 g of a leveling agent, 3 g of an antifoaming agent, 17.5 g of an associative thickener, and 20 g of deionized water are blended together, and the viscosity of the system is adjusted to reach 100,000 cps, thus obtaining the primer treatment agent.

[0032] Performance Testing An aqueous isocyanate curing agent is added to the primer treatment agents obtained in Application Examples 1 - 3, and the addition amount is 4 - 6 wt% of the primer treatment agent. After stirring evenly, according to the printing pattern, it is printed onto the fabric surface by means of screen printing. After printing, it is dried at a temperature of 60 - 80°C to obtain a primer treatment agent coating. Then, an aqueous printing paste is printed on the surface of the coating. After printing one pass, it is immediately dried, and the operations of printing and drying are repeated a total of 10 times until the required thickness of the printing layer (0.6 ± 0.1 mm) is reached, and the following tests are carried out; at the same time, a blank group is set up in this application as follows: an aqueous printing paste is printed on the surface of the coating. After printing one pass, it is immediately dried, and the operations of printing and drying are repeated a total of 10 times until the required thickness of the printing layer is reached, and then the test is carried out.

[0033] Testing method: The adhesion fastness is tested by using a tape. The tape is pasted on the printing layer, and then pulled up at a speed of 500 mm / min. Record the maximum pulling force (denoted as the adhesion fastness kgf / cm) when the layer structure is damaged, and observe the damaged cross-section. If the fabric surface is smooth without residual glue, it indicates that the fabric and the primer treatment agent layer or the primer treatment agent layer and the printing layer are separated; if there is a large amount of residual glue on the fabric surface, it indicates that the printing layer is damaged by cohesion.

[0034] The types of test fabrics include: a1. Polyester fabric; a2. Waterproof-treated polyester fabric; b1. TPEE fabric; b2. Waterproof-treated TPEE fabric; c1. TPEE and polyester blended fabric; c2. Waterproof-treated TPEE and polyester blended fabric; Table 1 Performance Testing Table Data Analysis: As can be seen from Table 1, for fabrics without any waterproofing treatment, in the absence of treatment agent, a small pulling force (≤2kgf / cm) can separate the fabric and the printing layer, and the fabric surface is smooth without residual glue, and the printing layer is intact and undamaged. When the fabric surface is treated, a larger pulling force (≥3.5kgf / cm) is required to destroy the bond between the fabric and the printing layer. The printing layer itself has been torn, but the printing glue layer is still adhered to the fabric surface, indicating that the fabric-priming agent layer and the primer layer-printing layer are not damaged.

[0035] Further testing, the fabric is first waterproofed. Since the fabric after waterproofing is more difficult to adhere, a smaller pulling force (≤0.5kgf / cm) can make the printing layer detach from the fabric surface; after the fabric surface is treated with a treatment agent, the tension is tested, and it is seen that the printing layer is torn under a larger pulling force (≥3.5kgf / cm), and is damaged by cohesion, while the fabric-priming treatment agent layer and the primer treatment agent layer-printing layer are still not damaged, indicating that the treatment agent still maintains a high bonding strength to the fabric and the printing layer. It proves that the present application has indeed produced a water-based polyurethane resin with excellent thermal activation properties, which can fully penetrate into the fiber of the fabric at a specific melting temperature and form a good bite with the fiber, thereby greatly improving the bonding strength between the difficult-to-attach fabric and the printing layer. It is made into a primer treatment agent, which can achieve effective infiltration and penetration of the fabric, enhance the mechanical interlocking ability between the primer treatment agent and the fabric, and can greatly optimize the spreadability and bonding strength of the printing layer, thereby effectively improving the stability of the overall structure.

[0036] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics, characterized in that, It includes the following steps: S1. Mix polyester polyol A, polyester polyol B and polyethylene glycol with a weight ratio of (120 - 160):(35 - 45):(4 - 6), heat up and dehydrate under vacuum conditions, then cool down, add diisocyanate monomer, and the weight ratio of diisocyanate monomer to polyester polyol A is (20 - 50):(120 - 160). Stir, heat up to 90 - 110 °C and keep the reaction for 2 - 3 h, cool down to 70 - 90 °C, add a catalyst and continue the reaction for 2 - 3 h, add a solvent and then cool down to obtain an intermediate product. The Mn of the polyester polyol A is 2000, and it includes one or more of adipic acid - ethylene glycol polyester polyol, adipic acid - 1,4 - butanediol polyester polyol and adipic acid - 1,6 - hexanediol polyester polyol. The Mn of the polyester polyol B is 3000, and it includes one or more of adipic acid - ethylene glycol polyester polyol, adipic acid - 1,4 - butanediol polyester polyol and adipic acid - 1,6 - hexanediol polyester polyol. The catalyst includes one or more of organic bismuth, organic tin T9 and organic tin T12; S2. Add chain extender A to the intermediate product obtained in step S1, stir at a speed of 80 - 100 rpm for 15 - 20 min, then add water and dilute and stir at a speed of 1200 - 1400 rpm for 5 - 10 min, add chain extender B, stir for 10 - 15 min and then adjust the speed to 60 - 80 rpm, heat up and reduce pressure until the mass in the system is constant to obtain an aqueous polyurethane resin. The chain extender B includes one or more of ethylenediamine, 1,2 - propanediamine, 1,6 - hexanediamine, isophorone diamine and hydroxyethyl ethylenediamine.

2. The preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics according to claim 1, characterized in that, In step S1, the polyester polyol A is adipic acid - 1,4 - butanediol polyester polyol.

3. The preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics according to claim 1, characterized in that, In step S1, the polyester polyol B is adipic acid - 1,6 - hexanediol polyester polyol.

4. The preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics according to claim 1, characterized in that, In step S1, the catalyst is organic bismuth.

5. The preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics according to claim 1, characterized in that, In step S2, the chain extender B is hydroxyethyl ethylenediamine.

6. The preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics according to claim 1, characterized in that, In step S1, the polyethylene glycol includes one or more of PEG - 1000, PEG - 2000 and PEG - 3000.

7. The preparation method of an aqueous polyurethane resin for primer treatment of printed fabrics according to claim 1, characterized in that, In step S1, the diisocyanate monomer includes 1,6 - hexamethylene diisocyanate and / or isophorone diisocyanate.

8. An aqueous polyurethane resin for primer treatment of printed fabrics obtained by the preparation method according to any one of claims 1 - 7.

9. A primer treatment agent, characterized in that, It is prepared by the following method: Blend the aqueous polyurethane resin according to claim 8 with other additives until the viscosity of the system reaches 90000 - 110000 CPS to obtain a primer treatment agent.

10. A primer treatment agent according to claim 9, characterized in that, The raw materials used include the following components in parts by weight: 95.0 - 96.0 parts of aqueous polyurethane resin; 0.3 - 0.5 part of wetting agent; 0.2 - 0.4 part of leveling agent; 0.2 - 0.4 part of defoaming agent; 1.5 - 2.0 parts of thickening agent; 1.0 - 3.0 parts of water.

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