Weather-resistant wet-process polyurethane resin as well as preparation method and application thereof

Abstract

The invention discloses a weather-resistant wet-process polyurethane resin and a preparation method and application thereof, and belongs to the technical field of polyurethane synthetic leather, the preparation method of the resin comprises the following steps: carrying out prepolymerization reaction on polyester diol and part of isocyanate to generate a prepolymer; the prepolymer and part of isocyanate are subjected to a tackifying reaction, then a chain extender and the remaining isocyanate are added for a chain extension reaction, finally, a multifunctional cross-linking agent is added for a cross-linking reaction, and a target product is obtained finally. The chain extender comprises hydroxyl-terminated dihydric alcohol and N-phenyl diethanol amine, and the number of hydroxyl groups in the polyfunctionality crosslinking agent is at least three. In the forming process of a molecular chain of the polyurethane resin, the molecular chain is lengthened in a plurality of different stages, and substances with different properties are respectively added in different stages to carry out corresponding reactions, so that the crosslinking degree of the resin is increased by optimizing a chain extension process; meanwhile, a resin network structure is optimized, so that the hydrolysis resistance and the peel strength of the resin are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane synthetic leather, and specifically relates to a weather-resistant wet-process polyurethane resin and a preparation method and application thereof. Background Art

[0002] Polyurethane (PU) synthetic leather is a new type of polymer composite material similar to natural leather, which is made of fiber fabric as the base material and PU resin as the surface coating by wet and dry processes. It has excellent mechanical properties such as excellent bonding performance with the base material, wear resistance, flex resistance, and aging resistance. It also has the advantages of easy processing, uniform quality, and low price. It is an ideal substitute for natural leather.

[0003] Although the mechanical properties of finished leather made of polyurethane resin based on traditional chain extension process are improved, there are problems such as insufficient cross-linking density of the resin, slippage of resin chain segments in high temperature and high humidity environment, resulting in unstable peeling strength, and easy decomposition of ester groups in constant temperature and humidity environment, resulting in decreased peeling of finished leather or surface cracking and powdering. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention improves the traditional chain extension process. During the formation of the polyurethane resin molecular chain, the molecular chain is extended in multiple different stages, and substances of different properties are added at different stages to carry out corresponding reactions. The chain extension process is optimized to increase the cross-linking degree of the resin itself, and the resin network structure is optimized to improve the hydrolysis resistance and peel strength of the resin.

[0005] The technical solution adopted by the present invention is as follows: The first object of the present invention is to provide a method for preparing a weather-resistant wet-process polyurethane resin, comprising the following steps: S1. Add polyester diol and antioxidant to a solvent accounting for 20%-35% of the total solvent in proportion, mix well, add isocyanate accounting for 10%-20% of the total isocyanate, carry out prepolymerization at 70-80°C for 20-30min, add catalyst accounting for 20%-50% of the total catalyst, continue reaction for 30-50min, and generate prepolymer; S2. Add part of isocyanate to the prepolymer to start the viscosity-increasing reaction. When the viscosity of the prepolymer increases to 5×10 4 -8×10 4 mPa.S / 60℃-70℃, stop adding isocyanate, add chain extender and solvent accounting for 35%-50% of the total solvent for dilution, stir evenly, and gradually add isocyanate accounting for 60%-80% of the total isocyanate for chain extension reaction; after reacting for 30-50min, add the remaining catalyst, continue to react for 30-50min, and then continue to add isocyanate until the viscosity reaches 2-5×104 mPa.S / 60℃-70℃, add multifunctional crosslinking agent in batches for crosslinking reaction. When the solid content reaches 35±1% and the viscosity reaches 12×10 4 -25×10 4 mPa.S / 25℃, stop adding the crosslinking agent, add the remaining solvent and the terminator to terminate the reaction, and obtain the weather-resistant wet-process polyurethane resin.

[0006] in: The chain extender includes terminal hydroxyl diol and N-phenyldiethanolamine; preferably, the terminal hydroxyl diol is a terminal hydroxyl diol with a linear molecular structure such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, etc. The use of terminal hydroxyl diol with a linear molecular structure helps to generate long linear macromolecular substances.

[0007] The number of hydroxyl groups in the multifunctional crosslinking agent is at least three; preferably, the multifunctional crosslinking agent is one of trimethylolethane, pentaerythritol, trimethylolpropane, and glycerol, and its function is to generate a three-dimensional network structure during the molecular polymerization process, while strengthening the hard segment, restricting the excessive movement of the soft segment, maintaining the flexibility of the soft segment, and avoiding the decrease of peel strength; The number average molecular weight of the polyester diol is 1000-4000; The isocyanate is at least one of 4,4'-diphenylmethane diisocyanate, a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate; The catalyst is a bismuth, zinc or amine catalyst.

[0008] The solvent is one of γ-butyrolactone, N,N-dimethylformamide (DMF), ε-caprolactone, dipropylene glycol dimethyl ether, propylene glycol methyl ether acetate, propylene glycol diacetate, and ethylene glycol diacetate.

[0009] In a further scheme, the mass parts of each reaction raw material are as follows: 100-140 parts of polyester diol, 11-15 parts of small molecule diol, 2-6 parts of N-phenyldiethanolamine, 1-2 parts of multifunctional cross-linking agent, 340-430 parts of solvent, 0.1-0.5 parts of antioxidant, 70-100 parts of isocyanate, 0.1-0.5 parts of terminator, and 1-2 parts of catalyst.

[0010] The second object of the present invention is to provide a weather-resistant wet-process polyurethane resin, which is prepared by the preparation method described in the first object above.

[0011] The third object of the present invention is to provide a sports equipment synthetic leather, wherein the sports equipment synthetic leather comprises the weather-resistant wet-process polyurethane resin as described in the second object above. Further, the sports equipment synthetic leather is prepared from a solvent, an additive, a color paste, a filler and a weather-resistant wet-process polyurethane resin.

[0012] Compared with the prior art, the present invention has the following beneficial effects: In the process of preparing the weather-resistant wet-process polyurethane resin of the present invention, a prepolymer is first synthesized, and after the prepolymer undergoes a viscosity-increasing reaction, a chain extension reaction is carried out using terminal hydroxyl diol and N-phenyldiethanolamine as chain extenders, and finally a cross-linking reaction is carried out under the action of a multifunctional cross-linking agent to increase the cross-linking density and prepare a product with excellent performance. The properties and working principles of each reactant added in the above different reaction stages are as follows: In the chain extension reaction, the terminal hydroxy diol helps the molecular chain structure to grow in the same direction, thereby generating long-chain macromolecular substances; the benzene ring structure in N-phenyldiethanolamine provides rigid support, and the dihydroxy group reacts with isocyanate to generate high-density carbamate bonds, making the distribution of cross-linking points more uniform, thereby improving the peel strength of the polyurethane; in addition, the benzene ring in N-phenyldiethanolamine has strong hydrophobicity, which can effectively block the penetration of water molecules into the resin to reduce the risk of carbamate bond hydrolysis; in addition, the conjugated electron effect of the benzene ring can stabilize the adjacent carbamate bonds and reduce their breakage rate in acidic or alkaline environments; in the subsequent cross-linking reaction, the three-dimensional cross-linked network formed by the multifunctional cross-linking agent can hinder the penetration path of water molecules inside the material, thereby delaying the diffusion process of the hydrolysis reaction.

[0013] The multifunctional crosslinking agent in the present invention has at least three hydroxyl groups, and its addition in the late stage of the reaction can generate a three-dimensional network structure, which can enhance the hard segment in the polyurethane structure while limiting the excessive movement of the soft segment, maintain the flexibility of the soft segment, and avoid the decrease in peel strength. It should be emphasized that the timing of adding the multifunctional crosslinking agent in the preparation method provided by the present invention has a direct impact on the performance of the final product. The multifunctional crosslinking agent cannot be added to the reaction system too early. The introduction of crosslinking points too early can easily lead to a sharp increase in the viscosity of the resin that is difficult to control. In addition, excessive crosslinking leads to limited movement of the molecular chain and reduced toughness of the material, which ultimately leads to the failure to obtain the performance of the target resin.

[0014] The weather-resistant wet-process polyurethane resin prepared by the present invention is used for preparing synthetic leather for sports equipment. Due to the introduction of N-phenyldiethanolamine, the polyurethane resin contains a benzene ring structure, the benzene ring is combined with the auxiliary agent molecule through the π-π stacking effect, and the hydroxyl group forms a hydrogen bond with the polar group of the auxiliary agent, and the two act simultaneously to anchor the auxiliary agent molecule in the resin matrix; in addition, the hydrophobic benzene ring and the hydrophilic hydroxyl group of the N-phenyldiethanolamine give it an amphiphilic property, improve the thermodynamic compatibility of the resin and the auxiliary agent, reduce the phase separation tendency, and improve the solvent resistance and anti-auxiliary agent precipitation ability of the synthetic leather product, so that an environmentally friendly synthetic leather product with good solvent resistance and good anti-auxiliary agent precipitation performance and excellent comprehensive performance can be prepared, and the surface of the synthetic leather product can be guaranteed not to be corroded in a working environment such as toluene or cyclohexanone. In addition, the excellent anti-additive precipitation ability can ensure that the synthetic leather product of the present invention can be stored for a long time in a high temperature and high humidity environment and ensure that there is no obvious additive precipitation on the surface of the synthetic leather product. After being tested at a constant temperature and humidity of 70°C with a humidity of 95% for one week, the synthetic leather product was flexed 80,000 times at room temperature without cracking, and there was no obvious additive precipitation on the surface. DETAILED DESCRIPTION

[0015] For ease of understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0016] Unless otherwise defined, all technical and scientific terms used in this patent have the same meaning as those commonly understood by technicians in the technical field of the present invention. The units of raw material usage in this patent refer to mass. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The raw materials used in the present invention are all commercially available products and are commercially available.

[0017] The models and manufacturers of the products / equipment used in the following examples are as follows: The catalyst model is MB20, an organic catalyst produced by Air Products and Chemicals, Inc. of the United States.

[0018] The polyester diol is adipic acid polyester diol, model number is SP-2313, number average molecular weight is 2300, produced by Hefei Anli Polyurethane New Materials Co., Ltd.

[0019] The isocyanate model is MDI, diphenylmethane diisocyanate produced by Wanhua Chemical.

[0020] The antioxidant model is Chinox 1010, produced by Double Bond Chemical Co., Ltd.

[0021] N-phenyldiethanolamine is produced by Guangdong Yuanfeng Chemical Technology Co., Ltd.

[0022] The cross-linking agent was trimethylolethane (TME), produced by Dongguan Hongli Chemical Technology Co., Ltd.

[0023] The above reagents are only for illustrating the sources and components of the reagents used in the experiments of the present invention so as to fully disclose the information, and do not mean that the present invention cannot be realized by using other similar reagents or reagents provided by other suppliers.

[0024] Example 1 This embodiment provides a weather-resistant wet-process polyurethane resin, and the raw materials used are as follows: Weigh the following by mass: 430 parts of solvent DMF, 120 parts of polyester diol SP-2313, 14 parts of ethylene glycol, 2 parts of N-phenyldiethanolamine, 2 parts of trimethylolethane, 1 part of catalyst MB20, 80 parts of aromatic diisocyanate MDI, 0.5 parts of antioxidant Chinox 1010, and 0.5 parts of terminator MeOH.

[0025] The preparation method comprises the following steps: S1. Add 100 parts of DMF, 120 parts of polyester diol SP-2313 and 0.5 parts of antioxidant Chinox1010 into the reaction bottle and stir evenly. Then add 10 parts of MDI, react at 70-80℃ for 0.5h, add 0.5 parts of MB20 to accelerate the reaction rate, and continue to react for 0.5h to generate prepolymer.

[0026] S2. Add MDI to the prepolymer to start the viscosity-increasing reaction, and the viscosity of the prepolymer increases to 7.2×10 4 mPa.S / 68℃, stop adding MDI. Then add 14 parts of ethylene glycol, 2 parts of N-phenyldiethanolamine and 160 parts of DMF for dilution. After stirring evenly, add 56 parts of MDI for chain extension reaction. After 0.5h of reaction, add 0.5 parts of MB20 to increase the reaction rate. After continuing the reaction for 0.5h, add MDI. When the viscosity reaches 2.7×10 4 mPa.S / 71℃, trimethylolethane was added in batches. When the solid content reached 35% and the viscosity reached 19×10 4 When the temperature reached mPa.S / 26°C, the addition of trimethylolethane was stopped, the remaining DMF was added for dilution, and 0.5 parts of MeOH was added to terminate the reaction to obtain a weather-resistant wet-process polyurethane resin.

[0027] Example 2 This embodiment provides a weather-resistant wet-process polyurethane resin, and the raw materials used are as follows: Weigh the following by mass: 430 parts of solvent DMF, 120 parts of polyester diol SP-2313, 14 parts of ethylene glycol, 4 parts of N-phenyldiethanolamine, 2 parts of trimethylolethane, 1 part of catalyst MB20, 85 parts of aromatic diisocyanate MDI, 0.5 parts of antioxidant Chinox 1010, and 0.5 parts of terminator MeOH.

[0028] The preparation method comprises the following steps: S1. Add 100 parts of DMF, 120 parts of polyester diol SP-2313 and 0.5 parts of antioxidant Chinox1010 into the reaction bottle and stir evenly. Then add 10 parts of MDI, react at 70-80℃ for 0.5h, add 0.5 parts of MB20 to accelerate the reaction rate, and continue to react for 0.5h to generate prepolymer.

[0029] S2. Add MDI into the prepolymer to start the viscosity-increasing reaction, and the viscosity of the prepolymer increases to 6.7×10 4 mPa.S / 68℃, stop adding MDI. Then add 14 parts of ethylene glycol, 4 parts of N-phenyldiethanolamine and 160 parts of DMF for dilution. After stirring evenly, add 59 parts of MDI for chain extension reaction. After 0.5h of reaction, add 0.5 parts of MB20 to increase the reaction rate. After continuing the reaction for 0.5h, add MDI. When the viscosity reaches 4.2×10 4 mPa.S / 66℃, trimethylolethane was added in batches. When the solid content reached 35% and the viscosity reached 17×10 4 When the temperature reached mPa.S / 26°C, the addition of trimethylolethane was stopped, the remaining DMF was added for dilution, and 0.5 parts of MeOH was added to terminate the reaction to obtain a weather-resistant wet-process polyurethane resin.

[0030] Example 3 This embodiment provides a weather-resistant wet-process polyurethane resin, and the raw materials used are as follows: Weigh the following by mass: 430 parts of solvent DMF, 120 parts of polyester diol SP-2313, 14 parts of ethylene glycol, 6 parts of N-phenyldiethanolamine, 2 parts of trimethylolethane, 1 part of catalyst MB20, 89 parts of aromatic diisocyanate MDI, 0.5 parts of antioxidant Chinox 1010, and 0.5 parts of terminator MeOH.

[0031] The preparation method comprises the following steps: S1. Add 100 parts of DMF, 120 parts of polyester diol SP-2313 and 0.5 parts of antioxidant Chinox1010 into the reaction bottle and stir evenly. Then add 10 parts of MDI, react at 70-80℃ for 0.5h, add 0.5 parts of MB20 to accelerate the reaction rate, and continue to react for 0.5h to generate prepolymer.

[0032] S2. Add MDI into the prepolymer to start the viscosity-increasing reaction, and the viscosity of the prepolymer increases to 7.4×10 4 mPa.S / 68℃, stop adding MDI. Then add 14 parts of ethylene glycol, 6 parts of N-phenyldiethanolamine and 160 parts of DMF for dilution. After stirring evenly, add 61 parts of MDI for chain extension reaction. After 0.5h of reaction, add 0.5 parts of MB20 to increase the reaction rate. After continuing the reaction for 0.5h, add MDI. When the viscosity reaches 3.4×10 4 mPa.S / 70℃, trimethylolethane was added in batches. When the solid content reached 35% and the viscosity reached 21×10 4 When the temperature reached mPa.S / 26°C, the addition of trimethylolethane was stopped, the remaining DMF was added for dilution, and 0.5 parts of MeOH was added to terminate the reaction to obtain a weather-resistant wet-process polyurethane resin.

[0033] Example 4 This embodiment provides a weather-resistant wet-process polyurethane resin, and the raw materials used are as follows: Weigh the following by mass: 430 parts of solvent DMF, 120 parts of polyester diol SP-2313, 14 parts of ethylene glycol, 12 parts of N-phenyldiethanolamine, 2 parts of trimethylolethane, 1 part of catalyst MB20, 94 parts of aromatic diisocyanate MDI, 0.5 parts of antioxidant Chinox 1010, and 0.5 parts of terminator MeOH.

[0034] The preparation method comprises the following steps: S1. Add 100 parts of DMF, 120 parts of polyester diol SP-2313 and 0.5 parts of antioxidant Chinox1010 into the reaction bottle and stir evenly. Then add 10 parts of MDI, react at 70-80℃ for 0.5h, add 0.5 parts of MB20 to accelerate the reaction rate, and continue to react for 0.5h to generate prepolymer.

[0035] S2. Add MDI into the prepolymer to start the viscosity-increasing reaction, and the viscosity of the prepolymer increases to 6.6×10 4 mPa.S / 68℃, stop adding MDI. Then add 14 parts of ethylene glycol, 12 parts of N-phenyldiethanolamine and 160 parts of DMF for dilution. After stirring evenly, add 66 parts of MDI for chain extension reaction. After 0.5h of reaction, add 0.5 parts of MB20 to increase the reaction rate. After continuing the reaction for 0.5h, add MDI. When the viscosity reaches 4.1×10 4 mPa.S / 71℃, trimethylolethane was added in batches. When the solid content reached 35% and the viscosity reached 23×10 4When the temperature reached mPa.S / 26°C, the addition of trimethylolethane was stopped, the remaining DMF was added for dilution, and 0.5 parts of MeOH was added to terminate the reaction to obtain a weather-resistant wet-process polyurethane resin.

[0036] Comparative Example 1 This comparative example adopts the same implementation as Example 1, and the difference from Example 1 is that the amount of ethylene glycol used in step S2 is 16 parts, and N-phenyldiethanol and trimethylolethane are not added. The other processes are the same as Example 1.

[0037] Comparative Example 2 This comparative example adopts the same implementation as Example 1, and the difference from Example 1 is that trimethylolethane is not added in step S2; other processes are the same as Example 1.

[0038] Comparative Example 3 This comparative example adopts the same implementation as Example 1, and the difference from Example 1 is that the amount of ethylene glycol used in step S2 is 16 parts, and N-phenyldiethanolamine is not added. The other processes are the same as Example 1.

[0039] Comparative Example 4 This comparative example adopts the same implementation as Example 4, and the difference from Example 4 is that the amount of ethylene glycol used in step S2 is 26 parts, and N-phenyldiethanolamine is not added. The other processes are the same as Example 4.

[0040] Application Examples The weather-resistant wet-process polyurethane resins prepared in the above-mentioned embodiments and comparative examples are prepared into synthetic leather, and the preparation method is as follows: 100 parts of weather-resistant wet-process polyurethane resin are mixed and stirred evenly with 50 parts of DMF solvent, 1 part of water, 1 part of cell regulator BYK-9525, 4 parts of black color paste and 10 parts of calcium carbonate filler, and then vacuumed. The vacuumed resin is poured on the cloth base, and after scraping, the cloth base is placed in a mixture of DMF and water for coagulation for 10 minutes. After washing, rolling and drying procedures, weather-resistant sports equipment synthetic leather is obtained.

[0041] Test Case The synthetic leather made of polyurethane prepared in the above embodiments and comparative examples was subjected to peel strength (GB / T 8949-2008) and hydrolysis resistance (jungle test) tests (QB / T 4671-2014). The specific data are shown in Table 1 below: Table 1

[0042] As can be seen from Table 1 above, the performance of the synthetic leather made of the polyurethane prepared in Examples 1 to 3 can meet the use requirements. After one week of jungle test, the leather surface did not peel and the peel strength decreased within 10%; starting from Example 3, with the increase in the amount of N-phenyldiethanolamine added, the peel strength of the finished leather has a downward trend. When N-phenyldiethanolamine is added to the proportion of Example 4, the finished leather feels hard and the peeling decreases significantly, while Comparative Example 4 adds ethylene glycol with the same total amount of ethylene glycol and N-phenyldiethanolamine as in Example 4, the leather surface is normal, and the leather feels not as hard as in Example 4; the reason for the decrease in peel strength in Example 4 may be that the rigid benzene ring in N-phenyldiethanolamine accounts for too much, resulting in a high proportion of hard segments, and the excessive aggregation of hard segment micro-regions destroys the microphase separation structure between the soft and hard segments, which is manifested macroscopically as a decrease in peel strength.

[0043] Comparative Example 1 does not add N-phenyldiethanolamine and trimethylolethane in the preparation process, and the peeling and hydrolysis resistance performance are much different from those of Example 1; Comparative Example 2 adds the same amount of N-phenyldiethanolamine as in Example 1, but does not add trimethylolethane, and the peeling strength of the finished leather is improved, and the hydrolysis resistance is improved compared with Comparative Example 1, but not as high as that of Example 1; Comparative Example 3 adds the same amount of trimethylolethane as in Example 1, does not add N-phenyldiethanolamine, but uses the same amount of ethylene glycol instead, and the peeling strength of the finished leather is not significantly improved, and the hydrolysis resistance is improved compared with Comparative Example 1, but not as good as that of Example 1. From the above analysis, it can be seen that only under the joint action of ethylene glycol, N-phenyldiethanolamine and trimethylolethane can a product with excellent peeling strength and hydrolysis resistance be obtained.

[0044] The peel strength (hot melt adhesive test) of the synthetic leather product prepared by the polyurethane resin prepared by the above-mentioned embodiments 1 to 3 is 70N / 2cm; the synthetic leather surface does not crack when the synthetic leather is soaked in a 10% NaOH solution at 25°C for 48 hours; the synthetic leather surface does not crack when the synthetic leather is soaked in a 10% NaOH solution at 70°C for 2 hours; the constant temperature and humidity (95% humidity and 70°C temperature) for one week: 60,000 flexures at room temperature do not crack, and no additives precipitate on the surface; the synthetic leather product has excellent wear resistance and weather resistance, and can be widely used in the field of sports equipment. It was found by infrared spectroscopy that the ester characteristic peak intensity retention rate of the resin containing N-phenyldiethanolamine after constant temperature and humidity treatment is greater than 90%, and the retention rate of the resin synthesized by the traditional chain extender is 65%.

[0045] It should be noted that in the above embodiments, when ethylene glycol is replaced by other terminal hydroxyl diols such as 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, etc.; or when trimethylolethane is replaced by other multifunctional cross-linking agents such as trimethylolpropane, glycerol, etc., the corresponding purposes can be achieved, and examples will not be given one by one.

[0046] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for preparing a weather-resistant wet-process polyurethane resin, characterized in that: The following steps are involved: The polyester diol, the antioxidant, and the solvent accounting for 20%-35% of the total solvent are mixed, and then 10%-20% of the isocyanate is added to carry out a prepolymerization reaction, and a part of the catalyst is added during the reaction to continue the reaction to form a prepolymer; Add part of isocyanate to the prepolymer for viscosity-increasing reaction, then add chain extender and part of solvent, mix well and gradually add the remaining isocyanate for chain extension reaction, add the remaining catalyst during the reaction, and after the viscosity of the system increases, add multifunctional cross-linking agent for cross-linking reaction, and the viscosity reaches 12×10 4 -25×10 4 mPa.S / 25°C, the remaining solvent is added and the terminator is added to terminate the reaction to obtain the target product; the chain extender includes terminal hydroxyl diol and N-phenyldiethanolamine; the number of hydroxyl groups in the multifunctional cross-linking agent is at least three.

2. The method for preparing a weather-resistant wet-process polyurethane resin according to claim 1, characterized in that: The mass ratio of the polyester diol, isocyanate, terminal hydroxy diol, N-phenyldiethanolamine and multifunctional crosslinking agent is (100-140): (70-100): (11-15): (2-6): (1-2).

3. The method for preparing a weather-resistant wet-process polyurethane resin according to claim 1, characterized in that: The terminal hydroxy diol is at least one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,5-pentanediol.

4. The method for preparing a weather-resistant wet-process polyurethane resin according to claim 1, characterized in that: The multifunctional cross-linking agent is at least one of trimethylolethane, pentaerythritol, trimethylolpropane and glycerol.

5. The method for preparing a weather-resistant wet-process polyurethane resin according to claim 1, characterized in that: The isocyanate is at least one of 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

6. The method for preparing a weather-resistant wet-process polyurethane resin according to claim 1, characterized in that: The catalyst is a bismuth catalyst, a zinc catalyst or an amine catalyst.

7. The method for preparing a weather-resistant wet-process polyurethane resin according to claim 1, characterized in that: The solvent is one of gamma-butyrolactone, N,N-dimethylformamide, epsilon-caprolactone, dipropylene glycol dimethyl ether, propylene glycol methyl ether acetate, propylene glycol diacetate, and ethylene glycol diacetate.

8. A weather-resistant wet-process polyurethane resin, characterized in that: The weather-resistant wet-process polyurethane resin is prepared by the preparation method according to any one of claims 1 to 7.

9. A synthetic leather for sports equipment, characterized in that: The sports equipment synthetic leather comprises the weather-resistant wet-process polyurethane resin according to claim 8.

10. The synthetic leather for sports equipment according to claim 9, characterized in that: The sports equipment synthetic leather is prepared from a solvent, an additive, a color paste, a filler and the weather-resistant wet-process polyurethane resin as claimed in claim 8.

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