An impact-resistant racquet surface coating and method of making the same

Abstract

The application relates to an anti-impact racket surface coating and a preparation method thereof, and belongs to the technical field of coatings; a multifunctional polyurethane chain extender is designed, rigid benzimidazole structures and flexible sulfide structures in the structure of the polyurethane chain extender help to enhance the tensile strength of the polyurethane, and energy dissipation after impact is accelerated, chain extension and strengthening effects of rigidity and toughness are realized; moreover, the reactivity of alcohol hydroxyl groups and amino structures in the chain extender structure of the application and isocyanate groups is quite different, the reaction of alcohol hydroxyl groups and amino groups will be carried out in steps in the chain extension reaction, the amino groups preferentially react to anchor molecular chains, and the hydroxyl groups are hysteresis reaction, which is beneficial to the formation of ordered hard segment microzones, the microphase separation degree in the system is enhanced, and the impact resistance is significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically, it relates to an impact-resistant racket surface coating and its preparation method. Background Technology

[0002] Badminton, as a sport that combines competitiveness and mass appeal, places increasingly stringent demands on racket performance. As the direct medium of transmission between the athlete and the shuttlecock, the performance of the racket's surface coating directly affects its lifespan, feel, and overall competitive performance. With the development of modern badminton towards higher speeds and greater intensity, the impact load on the racket at the moment of impact has significantly increased, placing higher demands on the impact resistance and abrasion resistance of the surface coating.

[0003] Based on this, the present invention provides an impact-resistant racket surface coating and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide an impact-resistant racket surface coating and its preparation method, in order to solve the problems mentioned in the background art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing an impact-resistant racket surface coating includes the following steps:

[0007] The first step involves reacting chlorolactic acid with o-phenylenediamine in a benzimidazole synthesis reaction to obtain a chain extender precursor.

[0008] The reaction process is as follows: under nitrogen protection, chlorolactic acid, o-phenylenediamine, and concentrated hydrochloric acid (20-30% by mass) are mixed in a reaction vessel. The reaction vessel is then placed in a microwave reactor and reacted for 20-40 minutes at a microwave power of 400-800W and a temperature of 100℃. After the reaction is completed, concentrated ammonia water is added to the system to neutralize the precipitate. The precipitate is then recrystallized with anhydrous ethanol to obtain the chain extender precursor.

[0009] The second step involves reacting the chain extender precursor with 3-mercaptopropylamine via a nucleophilic substitution reaction to obtain the chain extender.

[0010] The reaction process is as follows: Under nitrogen protection, the chain extender precursor, 3-mercaptopropylamine, and 60-80% (v / v) aqueous ethanol solution are mixed in a reaction vessel. The pH of the system is adjusted to 8-9 using 10-20% (w / v) potassium carbonate aqueous solution. The reaction is then carried out at 30-40℃ for 12-24 hours. After the reaction is completed, the solvent is removed by rotary evaporation of the reaction solution, and the remaining solid is recrystallized from anhydrous ethanol to obtain the chain extender.

[0011] The third step involves mixing isophorone diisocyanate, polytetrahydrofuran ether diol, and tin catalyst in a reaction vessel for prepolymerization. Then, chain extender and organic solvent are added to the system for chain extension reaction. Next, wear-resistant filler, ultraviolet absorber, film-forming aid, defoamer, and leveling agent are added to the system. After stirring and mixing evenly, degassing treatment is performed to obtain the impact-resistant racket surface coating.

[0012] Furthermore, the relative molecular mass of the polytetrahydrofuran ether diol used is 1000–2000.

[0013] Furthermore, the tin catalyst is at least one of dibutyltin dilaurate and stannous octoate.

[0014] Furthermore, the organic solvent is at least one of N,N-dimethylacetamide and dimethyl sulfoxide.

[0015] Furthermore, the wear-resistant filler is at least one of alumina and zinc oxide.

[0016] Furthermore, the ultraviolet absorber is at least one of ultraviolet absorber UV-326 and ultraviolet absorber UV-327.

[0017] Furthermore, the film-forming aid is propylene glycol methyl ether acetate.

[0018] Furthermore, the defoamer is at least one of YRXP-07 and YRXP-02.

[0019] Furthermore, the leveling agent is at least one of BYK-333 and BYK-306.

[0020] Furthermore, the prepolymerization conditions are a reaction at a temperature of 75–85°C for 2–3 hours.

[0021] Furthermore, the chain extension reaction is carried out at a temperature of 65–75°C for 1.5–2.5 h.

[0022] Furthermore, the mass ratio of isophorone diisocyanate, polytetrahydrofuran ether diol, tin catalyst, chain extender, organic solvent, wear-resistant filler, ultraviolet absorber, film-forming aid, defoamer, and leveling agent used is 30-40: 50-60: 0.1-0.3: 5-10: 20-40: 10-20: 1-2: 5-8: 0.2-0.5: 0.2-0.5.

[0023] The present invention also provides an impact-resistant racket surface coating prepared by the above preparation method.

[0024] The beneficial effects of this invention are:

[0025] This invention designs a polyurethane chain extender with a structure simultaneously incorporating benzimidazole, thioether, alcohol hydroxyl, and amino structures. The rigid benzimidazole and flexible thioether structures in this chain extender enhance the rigidity of the polyurethane hard segments, increasing the tensile strength and providing a strength foundation for impact resistance. The thioether structure, on the other hand, utilizes its flexibility to accelerate energy dissipation after impact. The combination of these two structures ultimately achieves a chain-extending and reinforcing effect that combines rigidity and toughness. Furthermore, the alcohol hydroxyl and amino structures in the chain extender exhibit significantly different reactivity with isocyanate groups. During the chain extension reaction, the reaction between the alcohol hydroxyl and amino groups proceeds stepwise, with the amino group reacting preferentially to anchor the molecular chain, while the hydroxyl group reacts later. This facilitates the formation of ordered hard segment microregions, enhances the degree of microphase separation in the system, and significantly improves impact resistance.

[0026] The chain extender designed in this invention contains a benzimidazole structure. When zinc oxide is selected as the wear-resistant filler, zinc oxide can form a good coordination effect with benzimidazole, forming a molecular bridge between the wear-resistant filler and the polyurethane matrix. This significantly improves the dispersion and interfacial bonding of the reinforcing filler in the polyurethane matrix. Moreover, these reversible zinc-benzimidazole coordination bonds can also be preferentially broken as sacrificial bonds during friction or impact, and reformed after stress dissipation, achieving a balance between energy dissipation and structural stability, and reducing the damage of external forces to the covalent backbone. Detailed Implementation

[0027] This invention provides an impact-resistant racket surface coating and its preparation method. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and fall within the scope of protection of this invention. The method and application of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the method and application described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0028] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0029] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0030] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0031] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items.

[0032] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0033] The use of any and all instances or exemplary language such as “e.g.” or “including” in this document is merely intended to better illustrate the invention and is not intended to limit the scope of the invention unless the claims are made. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0034] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0035] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0036] The embodiments and comparative examples of this invention describe some examples, in which the embodiments illustrate certain implementations of the invention. However, this does not mean that the effects of the invention can only be achieved in these examples.

[0037] To further illustrate the present invention, the following describes in detail a title and its preparation method provided by the present invention with reference to embodiments.

[0038] Example 1

[0039] A method for preparing an impact-resistant racket surface coating includes the following steps:

[0040] Step 1: Under nitrogen protection, mix 12 parts by mass of chlorolactic acid, 10 parts by mass of o-phenylenediamine, and 100 parts by mass of 30% concentrated hydrochloric acid in a reaction vessel. Then place the reaction vessel in a microwave reactor and react for 40 minutes at a microwave power of 400W and a temperature of 100℃. After the reaction is completed, add concentrated ammonia water to the system to neutralize the precipitate. Then recrystallize the precipitate with anhydrous ethanol to obtain the chain extender precursor.

[0041] Step 2: By mass fraction, 14 parts of chain extender precursor, 8 parts of 3-mercaptopropylamine, and 80 parts of 80% (v / v) aqueous ethanol solution were mixed in a reaction vessel under nitrogen protection. The pH of the system was adjusted to 8 using 10% (v / v) potassium carbonate aqueous solution. The reaction was then carried out at 30°C for 24 hours. After the reaction was completed, the solvent was removed by rotary evaporation of the reaction solution. The remaining solid was recrystallized from anhydrous ethanol to obtain the chain extender.

[0042] Step 3: By mass, mix 30 parts of isophorone diisocyanate, 50 parts of polytetrahydrofuran ether diol, and 0.1 parts of dibutyltin dilaurate in a reaction vessel and react at 75°C for 3 hours. Then, add 5 parts of chain extender and 20 parts of N,N-dimethylacetamide to the system and react at 65°C for 2.5 hours. Next, add 20 parts of alumina, 1 part of UV absorber UV-326, 5 parts of propylene glycol methyl ether acetate, 0.2 parts of defoamer YRXP-07, and 0.2 parts of leveling agent BYK-333 to the system. After stirring and mixing evenly, degas the mixture to obtain the impact-resistant racket surface coating.

[0043] In this embodiment, the relative molecular mass of the polytetrahydrofuran ether diol is 2000.

[0044] An impact-resistant racket surface coating prepared by the above method.

[0045] Example 2

[0046] A method for preparing an impact-resistant racket surface coating includes the following steps:

[0047] Step 1: Under nitrogen protection, mix 12 parts by mass of chlorolactic acid, 10 parts by mass of o-phenylenediamine, and 100 parts by mass of 30% concentrated hydrochloric acid in a reaction vessel. Then place the reaction vessel in a microwave reactor and react for 40 minutes at a microwave power of 400W and a temperature of 100℃. After the reaction is completed, add concentrated ammonia water to the system to neutralize the precipitate. Then recrystallize the precipitate with anhydrous ethanol to obtain the chain extender precursor.

[0048] Step 2: By mass fraction, 14 parts of chain extender precursor, 8 parts of 3-mercaptopropylamine, and 80 parts of 80% (v / v) aqueous ethanol solution were mixed in a reaction vessel under nitrogen protection. The pH of the system was adjusted to 8 using 10% (v / v) potassium carbonate aqueous solution. The reaction was then carried out at 30°C for 24 hours. After the reaction was completed, the solvent was removed by rotary evaporation of the reaction solution. The remaining solid was recrystallized from anhydrous ethanol to obtain the chain extender.

[0049] Step 3: By weight, mix 30 parts isophorone diisocyanate, 50 parts polytetrahydrofuran ether diol, and 0.1 parts dibutyltin dilaurate in a reaction vessel and react at 75°C for 3 hours. Then, add 5 parts chain extender and 20 parts N,N-dimethylacetamide to the system and react at 65°C for 2.5 hours. Next, add 20 parts zinc oxide, 1 part UV absorber UV-326, 5 parts propylene glycol methyl ether acetate, 0.2 parts defoamer YRXP-07, and 0.2 parts leveling agent BYK-333 to the system. After stirring and mixing evenly, defoaming treatment is performed to obtain the impact-resistant racket surface coating.

[0050] In this embodiment, the polytetrahydrofuran ether diol has a relative molecular mass of 2000.

[0051] An impact-resistant racket surface coating prepared by the above method.

[0052] Example 3

[0053] A method for preparing an impact-resistant racket surface coating includes the following steps:

[0054] Step 1: Under nitrogen protection, mix 13 parts by mass of chlorolactic acid, 10 parts by mass of o-phenylenediamine, and 110 parts by mass of 25% concentrated hydrochloric acid in a reaction vessel. Then place the reaction vessel in a microwave reactor and react for 30 minutes at a microwave power of 600W and a temperature of 100℃. After the reaction is completed, add concentrated ammonia water to the system to neutralize the precipitate. Then recrystallize the precipitate with anhydrous ethanol to obtain the chain extender precursor.

[0055] Step 2: By mass fraction, 14 parts of chain extender precursor, 10 parts of 3-mercaptopropylamine, and 90 parts of 70% (v / v) aqueous ethanol solution were mixed in a reaction vessel under nitrogen protection. The pH of the system was adjusted to 8.5 using 15% (v / v) potassium carbonate aqueous solution. The reaction was then carried out at 35°C for 18 hours. After the reaction was completed, the solvent was removed by rotary evaporation of the reaction solution. The remaining solid was recrystallized from anhydrous ethanol to obtain the chain extender.

[0056] Step 3: By mass, mix 35 parts of isophorone diisocyanate, 55 parts of polytetrahydrofuran ether diol, and 0.2 parts of stannous octoate in a reaction vessel and react at 80°C for 2.5 hours. Then, add 7.5 parts of chain extender and 30 parts of dimethyl sulfoxide to the system and react at 70°C for 2 hours. Next, add 30 parts of alumina, 1.5 parts of UV absorber UV-327, 6.5 parts of propylene glycol methyl ether acetate, 0.35 parts of defoamer YRXP-02, and 0.35 parts of leveling agent BYK-306 to the system. After stirring and mixing evenly, degas the mixture to obtain the impact-resistant racket surface coating.

[0057] In this embodiment, the polytetrahydrofuran ether diol has a relative molecular mass of 1500.

[0058] An impact-resistant racket surface coating prepared by the above method.

[0059] Example 4

[0060] A method for preparing an impact-resistant racket surface coating includes the following steps:

[0061] Step 1: Under nitrogen protection, mix 13 parts by mass of chlorolactic acid, 10 parts by mass of o-phenylenediamine, and 110 parts by mass of 25% concentrated hydrochloric acid in a reaction vessel. Then place the reaction vessel in a microwave reactor and react for 30 minutes at a microwave power of 600W and a temperature of 100℃. After the reaction is completed, add concentrated ammonia water to the system to neutralize the precipitate. Then recrystallize the precipitate with anhydrous ethanol to obtain the chain extender precursor.

[0062] Step 2: By mass fraction, 14 parts of chain extender precursor, 10 parts of 3-mercaptopropylamine, and 90 parts of 70% (v / v) aqueous ethanol solution were mixed in a reaction vessel under nitrogen protection. The pH of the system was adjusted to 8.5 using 15% (v / v) potassium carbonate aqueous solution. The reaction was then carried out at 35°C for 18 hours. After the reaction was completed, the solvent was removed by rotary evaporation of the reaction solution. The remaining solid was recrystallized from anhydrous ethanol to obtain the chain extender.

[0063] Step 3: By mass, mix 35 parts of isophorone diisocyanate, 55 parts of polytetrahydrofuran ether diol, and 0.2 parts of stannous octoate in a reaction vessel and react at 80°C for 2.5 hours. Then, add 7.5 parts of chain extender and 30 parts of dimethyl sulfoxide to the system and react at 70°C for 2 hours. Next, add 30 parts of zinc oxide, 1.5 parts of UV absorber UV-327, 6.5 parts of propylene glycol methyl ether acetate, 0.35 parts of defoamer YRXP-02, and 0.35 parts of leveling agent BYK-306 to the system. After stirring and mixing evenly, degas the mixture to obtain the impact-resistant racket surface coating.

[0064] In this embodiment, the polytetrahydrofuran ether diol has a relative molecular mass of 1500.

[0065] An impact-resistant racket surface coating prepared by the above method.

[0066] Example 5

[0067] A method for preparing an impact-resistant racket surface coating includes the following steps:

[0068] Step 1: Under nitrogen protection, mix 14 parts by mass of chlorolactic acid, 10 parts by mass of o-phenylenediamine, and 120 parts by mass of 20% concentrated hydrochloric acid in a reaction vessel. Then place the reaction vessel in a microwave reactor and react for 20 minutes at a microwave power of 800W and a temperature of 100℃. After the reaction is completed, add concentrated ammonia water to the system to neutralize the precipitate. Then recrystallize the precipitate with anhydrous ethanol to obtain the chain extender precursor.

[0069] Step 2: By mass fraction, 14 parts of chain extender precursor, 12 parts of 3-mercaptopropylamine, and 100 parts of 60% (v / v) aqueous ethanol solution were mixed in a reaction vessel under nitrogen protection. The pH of the system was adjusted to 9 using 20% ​​(v / v) potassium carbonate aqueous solution. The reaction was then carried out at 40°C for 12 hours. After the reaction was completed, the solvent was removed by rotary evaporation of the reaction solution. The remaining solid was recrystallized from anhydrous ethanol to obtain the chain extender.

[0070] Step 3: By mass, mix 40 parts of isophorone diisocyanate, 60 parts of polytetrahydrofuran ether diol, and 0.3 parts of dibutyltin dilaurate in a reaction vessel and react at 85°C for 2 hours. Then, add 10 parts of chain extender and 40 parts of N,N-dimethylacetamide to the system and react at 75°C for 1.5 hours. Next, add 40 parts of alumina, 2 parts of UV absorber UV-327, 8 parts of propylene glycol methyl ether acetate, 0.5 parts of defoamer YRXP-07, and 0.5 parts of leveling agent BYK-333 to the system. After stirring and mixing evenly, degas the mixture to obtain the impact-resistant racket surface coating.

[0071] In this embodiment, the polytetrahydrofuran ether diol has a relative molecular mass of 1000.

[0072] An impact-resistant racket surface coating prepared by the above method.

[0073] Example 6

[0074] A method for preparing an impact-resistant racket surface coating includes the following steps:

[0075] Step 1: Under nitrogen protection, mix 14 parts by mass of chlorolactic acid, 10 parts by mass of o-phenylenediamine, and 120 parts by mass of 20% concentrated hydrochloric acid in a reaction vessel. Then place the reaction vessel in a microwave reactor and react for 20 minutes at a microwave power of 800W and a temperature of 100℃. After the reaction is completed, add concentrated ammonia water to the system to neutralize the precipitate. Then recrystallize the precipitate with anhydrous ethanol to obtain the chain extender precursor.

[0076] Step 2: By mass fraction, 14 parts of chain extender precursor, 12 parts of 3-mercaptopropylamine, and 100 parts of 60% (v / v) aqueous ethanol solution were mixed in a reaction vessel under nitrogen protection. The pH of the system was adjusted to 9 using 20% ​​(v / v) potassium carbonate aqueous solution. The reaction was then carried out at 40°C for 12 hours. After the reaction was completed, the solvent was removed by rotary evaporation of the reaction solution. The remaining solid was recrystallized from anhydrous ethanol to obtain the chain extender.

[0077] Step 3: By mass, mix 40 parts of isophorone diisocyanate, 60 parts of polytetrahydrofuran ether diol, and 0.3 parts of dibutyltin dilaurate in a reaction vessel and react at 85°C for 2 hours. Then, add 10 parts of chain extender and 40 parts of N,N-dimethylacetamide to the system and react at 75°C for 1.5 hours. Next, add 40 parts of zinc oxide, 2 parts of UV absorber UV-327, 8 parts of propylene glycol methyl ether acetate, 0.5 parts of defoamer YRXP-07, and 0.5 parts of leveling agent BYK-333 to the system. After stirring and mixing evenly, degas the mixture to obtain the impact-resistant racket surface coating.

[0078] In this embodiment, the polytetrahydrofuran ether diol has a relative molecular mass of 1000.

[0079] An impact-resistant racket surface coating prepared by the above method.

[0080] Comparative Example 1

[0081] The difference between this comparative example and Example 5 is that, instead of preparing a chain extender, an equal mass of commercially available chain extender 1,4-butanediol was used to replace the chain extender used in Example 5.

[0082] Comparative Example 2

[0083] The difference between this comparative example and Example 6 is that, instead of preparing a chain extender, an equal mass of commercially available chain extender 1,4-butanediol was used to replace the chain extender used in Example 6.

[0084] Experimental Example 1

[0085] The impact-resistant racket surface coatings obtained in Examples 1-6 and Comparative Examples 1-2 were applied to the surface of the test substrate. After baking at 80°C for 3 hours, the samples were left to stand at room temperature for 24 hours. The maximum impact height of each component sample was tested according to the national standard GB / T 1732-2020 "Determination of Impact Resistance of Paint Films". The abrasion resistance of each component sample was tested according to the national standard GB / T 1768-2006 "Determination of Abrasion Resistance of Paints and Varnishes - Rotating Rubber Grinding Wheel Method". The tensile strength and elongation at break of each component sample were tested according to GB / T 1040.3-2006 "Determination of Tensile Properties of Plastics - Part 3: Test Conditions for Films and Sheets". The test results are shown in Table 1.

[0086] Table 1

[0087]

[0088] As can be seen from Table 1, the impact-resistant racket surface coatings of the present invention in Examples 1 to 6 have better impact resistance and wear resistance, and their tensile strength and elongation at break are also better than those in Comparative Examples 1 to 2. Since the wear-resistant filler used in Examples 1, 3, and 5 is alumina, its coordination ability with the benzimidazole structure is weaker than that of zinc oxide. Therefore, the overall performance of the impact-resistant racket surface coatings in Examples 1, 3, and 5 is weaker than that in Examples 2, 4, and 6.

[0089] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an impact-resistant racket surface coating, characterized in that, Includes the following steps: The first step involves reacting chlorolactic acid with o-phenylenediamine in a benzimidazole synthesis reaction to obtain a chain extender precursor. The second step involves reacting the chain extender precursor with 3-mercaptopropylamine via a nucleophilic substitution reaction to obtain the chain extender. The third step involves mixing isophorone diisocyanate, polytetrahydrofuran ether diol, and tin catalyst in a reaction vessel for prepolymerization. Then, chain extender and organic solvent are added to the system and a chain extension reaction is carried out. Next, wear-resistant filler, ultraviolet absorber, film-forming aid, defoamer, and leveling agent are added to the system. After stirring and mixing evenly, degassing treatment is performed to obtain the impact-resistant racket surface coating. The wear-resistant filler is zinc oxide; The conditions for the synthesis of benzimidazole are as follows: Chlorolactic acid, o-phenylenediamine, and 20-30% concentrated hydrochloric acid were mixed in a reaction vessel under nitrogen protection. The reaction vessel was then placed in a microwave reactor and reacted at a microwave power of 400-800W and a temperature of 100°C to obtain the chain extender precursor. The conditions for nucleophilic substitution reactions to occur are: Under nitrogen protection, the chain extender precursor, 3-mercaptopropylamine, and 60-80% (v / v) aqueous ethanol solution were mixed in a reaction vessel. The pH of the system was adjusted to 8-9 using 10-20% (w / v) aqueous potassium carbonate solution. The reaction was then carried out at 30-40°C to obtain the chain extender.

2. The method for preparing an impact-resistant racket surface coating according to claim 1, characterized in that, The tin catalyst is at least one of dibutyltin dilaurate and stannous octoate.

3. The method for preparing an impact-resistant racket surface coating according to claim 1, characterized in that, The organic solvent is at least one of N,N-dimethylacetamide and dimethyl sulfoxide.

4. The method for preparing an impact-resistant racket surface coating according to claim 1, characterized in that, The ultraviolet absorber is at least one of ultraviolet absorber UV-326 and ultraviolet absorber UV-327.

5. The method for preparing an impact-resistant racket surface coating according to claim 1, characterized in that, The film-forming aid is propylene glycol methyl ether acetate, the defoamer is at least one of YRXP-07 and YRXP-02, and the leveling agent is at least one of BYK-333 and BYK-306.

6. The method for preparing an impact-resistant racket surface coating according to claim 1, characterized in that, The prepolymerization conditions are a reaction at 75–85°C for 2–3 hours, and the chain extension reaction conditions are a reaction at 65–75°C for 1.5–2.5 hours.

7. The method for preparing an impact-resistant racket surface coating according to claim 1, characterized in that, The mass ratio of isophorone diisocyanate, polytetrahydrofuran ether diol, tin catalyst, chain extender, organic solvent, wear-resistant filler, ultraviolet absorber, film-forming aid, defoamer, and leveling agent used is 30-40:50-60:0.1-0.3:5-10:20-40:10-20:1-2:5-8:0.2-0.5:0.2-0.

5.

8. An impact-resistant racket surface coating prepared by the method described in claim 1.

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