Waterproof and UV-resistant coating for rubber surface and preparation method thereof

Abstract

The invention discloses a coating with waterproof and anti-ultraviolet functions for rubber surface and a preparation method, belonging to the field of surface modification materials. The present invention first performs thermal polymerization reaction and induces precipitation after mixing methoxyethyl methacrylate, isobornyl acrylate, thermal initiator ammonium persulfate and organic solvent, and separates to obtain a solid phase polymer; then the solid phase polymer is mixed with an anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone to form a solid phase material, and then gradually adds a coating solvent that does not corrode the rubber but can dissolve the solid phase material, until all the solid phase materials are just completely dissolved to form an anti-ultraviolet coating for coating and curing on the rubber surface. The coating of the present invention can form a reliable anti-ultraviolet coating on the rubber surface, and can significantly improve the long-term resistance to ultraviolet rays of the rubber under the condition that the mechanical properties of the rubber are hardly changed.

Description

Technical Field

[0001] The invention belongs to the field of surface modification materials, and in particular relates to a coating with waterproof and UV-resistant functions for rubber surface and a preparation method thereof. Background Art

[0002] Natural rubber is a natural polymer compound, the main component of which is rubber hydrocarbon. Rubber hydrocarbon is a polymer compound formed by addition polymerization of isoprene monomers, with a molecular formula of (C5H8)n. Due to its unique molecular structure, natural rubber has excellent elasticity, insulation, waterproofness and plasticity. These properties make natural rubber widely used in modern industry and daily life.

[0003] In industrial production, natural rubber is used as an important raw material for manufacturing tires, seals, shock absorbers and other products. Tires are the largest consumer of natural rubber, and its excellent elasticity and wear resistance ensure the safety and comfort of vehicles. Seals and shock absorbers use the high elasticity and durability of rubber to effectively prevent liquid leakage and mechanical vibration. In addition, natural rubber is also widely used in the insulation layer of wires and cables to prevent current leakage and short circuit accidents.

[0004] Natural rubber also plays an important role in daily life. Common items such as rubber gloves, rubber bands, and rubber soles all rely on the excellent properties of natural rubber. Rubber gloves have good waterproof and insulating properties and are widely used in medical, food processing and other fields that require high cleanliness and safety. Rubber bands are widely used to bundle and fix various items due to their elasticity and durability. Rubber soles provide people with a comfortable and safe wearing experience through their good elasticity and wear resistance.

[0005] However, there are also some problems with natural rubber during use. Due to the presence of unsaturated bonds such as double bonds in its molecular structure, natural rubber is prone to molecular chain breakage when exposed to ultraviolet rays and oxygen for a long time. This molecular chain breakage will cause a significant decline in the performance of the rubber material, such as reduced elasticity, increased hardness, and brittle cracking, thereby greatly shortening the service life of rubber products.

[0006] In order to extend the service life of natural rubber products, people have conducted a lot of research work. The utility model patent entitled "Anti-ultraviolet wear-resistant composite film for rubber surface" and publication number CN201921018691.2 discloses a surface protection film applied to the rubber surface, which is not only wear-resistant and corrosion-resistant, but also has the function of preventing the rubber from aging under ultraviolet exposure. However, this design has the following problems and disadvantages. Although it has excellent wear resistance and anti-ultraviolet performance, its tensile properties are poor, which limits its application in large deformation environments. The invention patent entitled "The use of titanium dioxide as an anti-ultraviolet agent in rubber compositions" and publication number CN1313878A discloses a method of using titanium dioxide particles to add to rubber to resist ultraviolet aging, but this design has the following problem: adding anti-ultraviolet agents to rubber will affect the mechanical properties of the rubber. Therefore, how to provide the rubber with anti-ultraviolet aging ability without changing its mechanical properties is a technical problem that needs to be solved urgently. Summary of the invention

[0007] The purpose of the present invention is to solve the problems existing in the prior art and provide a waterproof and UV-resistant coating for rubber surface and a preparation method thereof. The present invention can significantly improve the ability of rubber to resist UV rays without changing its mechanical properties.

[0008] The specific technical solutions adopted by the present invention are as follows:

[0009] In a first aspect, the present invention provides a method for preparing a coating with waterproof and UV-resistant functions for a rubber surface, comprising:

[0010] S1: Methoxyethyl methacrylate (MEA), isobornyl acrylate (IBA), thermal initiator ammonium persulfate and organic solvent are mixed to form a precursor solution, the precursor solution is heated to perform a thermal polymerization reaction, and the resulting mixed solution is dropped into water to induce precipitation of the polymer product, and finally centrifuged to obtain a solid phase polymer;

[0011] S2: The dried solid polymer is mixed with the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone to form a solid material, and then a coating solvent that does not corrode the rubber but can dissolve the solid material is gradually added until all the solid materials are completely dissolved to form an anti-ultraviolet coating for coating and curing on the rubber surface.

[0012] As a preferred embodiment of the first aspect, in the precursor solution, the mass ratio of methoxyethyl methacrylate, isobornyl acrylate and thermal initiator is (1.2~1.4): 1: (0.01~0.02).

[0013] As a preferred embodiment of the first aspect, the reaction temperature of the thermal polymerization reaction is 50-70 °C, the reaction time is 6-8 h, and the reaction requires stirring throughout the process.

[0014] As a preferred embodiment of the first aspect, the organic solvent is N,N-dimethylformamide (DMF).

[0015] As a preferred embodiment of the first aspect, the coating solvent is dichloromethane or N,N-dimethylformamide.

[0016] As a preferred embodiment of the first aspect, the solid phase polymer needs to be dried in an environment of 35-45° C. before being mixed with the anti-ultraviolet agent.

[0017] As a preferred embodiment of the first aspect above, in the solid phase material, the mass ratio of the solid phase polymer to the anti-ultraviolet agent is (2-5):1.

[0018] In a second aspect, the present invention provides a coating with waterproof and UV resistance functions for use on rubber surfaces, which is prepared according to the coating preparation method as described in any one of the schemes of the first aspect above.

[0019] In a third aspect, the present invention provides a method for preparing an anti-ultraviolet coating for rubber, characterized in that after the anti-ultraviolet coating is prepared according to the coating preparation method as described in any one of the schemes of the first aspect above, it is applied to the rubber surface and cured at a temperature of 55~65°C to form an anti-ultraviolet coating on the rubber surface.

[0020] As a preferred embodiment of the third aspect, the anti-ultraviolet coating is coated on the rubber surface by spin coating, dip coating or brush coating.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a coating with waterproof and anti-ultraviolet function for rubber surface and a preparation method thereof, wherein the coating is prepared by mixing and dissolving a solid phase polymer obtained by thermal initiation polymerization and an anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone, wherein the coating components can be completely miscible to ensure uniformity, and at the same time, its performance matches that of the rubber substrate, and can effectively avoid the phenomenon of coating damage when the rubber substrate undergoes large deformation behavior. Therefore, the coating of the present invention can significantly improve its ability to resist ultraviolet rays for a long time without almost changing the mechanical properties of the rubber. At the same time, the coating preparation method of the present invention is simple, low in cost, conducive to industrial production and assembly line manufacturing, and has a good market application and promotion prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1The mass ratio a:b of the solid phase polymer to the anti-ultraviolet agent in the embodiment of the present invention corresponds to the fracture stress of the rubber.

[0024] Figure 2 This is the effect of using different solvents to dissolve on the UV resistance in the embodiments of the present invention.

[0025] Figure 3 This is a test of the UV transmittance of the coating in the embodiment of the present invention.

[0026] Figure 4 Result diagrams of the contact angle of uncoated rubber (left) and coated rubber (right) in an embodiment of the present invention.

[0027] Figure 5 This is a test of the tensile properties of the coating in the embodiment of the present invention.

[0028] Figure 6 Scanning electron microscope images of rubber materials with and without coating. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation mode of the present invention is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0030] In a preferred embodiment of the present invention, a method for preparing a coating with waterproof and UV-resistant functions for a rubber surface is provided, the method specifically comprising the following steps:

[0031] S1: A precursor solution is formed by mixing methoxyethyl methacrylate (MEA), isobornyl acrylate (IBA), thermal initiator ammonium persulfate (molecular formula (NH4)2S2O8) and an organic solvent. The precursor solution is heated to perform a thermal polymerization reaction, and the resulting mixed solution is dropped into water to induce precipitation of the polymerization product. Finally, the solid phase polymer is obtained by centrifugation.

[0032] S2: The dried solid polymer is mixed with the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone to form a solid material, and then a coating solvent that does not corrode the rubber but can dissolve the solid material is gradually added until all the solid materials are completely dissolved to form an anti-ultraviolet coating for coating and curing on the rubber surface.

[0033] The anti-ultraviolet coating prepared based on the above steps S1 and S2 can be evenly covered on the rubber surface by coating, and a layer of anti-ultraviolet coating can be formed after curing.

[0034] In actual application scenarios, rubber materials often need to bear large deformations in the form of stretching, compression, etc. Therefore, the properties of the components constituting the coating must be able to match the rubber substrate so that they can be stably attached to the rubber surface for a long time and form a stable and reliable anti-ultraviolet protection ability. Therefore, not any adhesive and anti-ultraviolet agent can be mixed to form a coating formula that meets the requirements of rubber surface coating. In the above-mentioned coating preparation method of the present invention, a solid phase polymer that can be fully and evenly mixed with an anti-ultraviolet agent is first synthesized by a thermal polymerization method, and then the solid phase polymer is mixed with the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone as a coating solid phase material, and the coating solvent is used to dissolve it to form an anti-ultraviolet coating that can be applied to the rubber surface. In this coating, the two solid phase materials can be miscible with each other in the solvent to avoid uneven distribution. At the same time, the performance of the liquid coating finally prepared matches the rubber substrate, effectively preventing the phenomenon of coating damage when the rubber substrate undergoes large deformation behavior, thereby ensuring the anti-ultraviolet ability of the rubber surface for a long time. Therefore, the coating of the present invention can significantly improve its ability to resist ultraviolet rays under the condition of almost no change in the mechanical properties of the rubber.

[0035] In addition, in the above coating preparation method, process parameters such as the ratio of each component and reaction conditions can be adjusted and optimized according to actual conditions.

[0036] In an embodiment of the present invention, in the precursor solution, the mass ratio of methoxyethyl methacrylate, isobornyl acrylate and thermal initiator ammonium persulfate is preferably (1.2~1.4): 1: (0.01~0.02).

[0037] In an embodiment of the present invention, the reaction temperature of the thermal polymerization reaction is preferably 50-70 °C, the reaction time is preferably 6-8 h, and the reaction requires stirring throughout the process.

[0038] In an embodiment of the present invention, the organic solvent is preferably N,N-dimethylformamide (DMF), which can dissolve and disperse the components in the precursor solution well and realize efficient thermal polymerization reaction.

[0039] In the embodiment of the present invention, the coating solvent is preferably dichloromethane (CH2Cl2) or N,N-dimethylformamide. These two solvents will not affect the mechanical properties of the rubber substrate and can dissolve and disperse the two solid phase materials well.

[0040] In an embodiment of the present invention, the solid phase polymer needs to be dried in an environment of 35-45° C. before being mixed with the anti-ultraviolet agent.

[0041] In an embodiment of the present invention, in the solid phase material, the mass ratio of the solid phase polymer to the anti-ultraviolet agent is preferably (2-5): 1. This component ratio has been experimentally optimized to ensure that the performance of the final coating matches the rubber substrate, ensure that the coating has good mechanical properties, and effectively prevent the coating from being damaged when the rubber material undergoes large deformation.

[0042] In an embodiment of the present invention, an anti-ultraviolet coating can be further prepared based on the above coating preparation method, and a method for preparing an anti-ultraviolet coating for rubber is provided, wherein the anti-ultraviolet coating is applied to the rubber surface, and cured at a temperature of 55 to 65°C to form an anti-ultraviolet coating on the rubber surface. The anti-ultraviolet coating can be applied to the rubber surface by spin coating, dip coating or brush coating, etc., and the uniformity of the coating needs to be ensured.

[0043] The specific preparation method and performance of the waterproof and UV-resistant coating and rubber coating for rubber surface are demonstrated through a number of specific embodiments.

[0044] Comparative Example 1

[0045] In this comparative example, the anti-ultraviolet coating is prepared by photopolymerization of a photoinitiator under ultraviolet initiation, comprising the following steps:

[0046] (1) Methoxyethyl methacrylate, isobornyl acrylate and photoinitiator benzophenone were mixed in a mass ratio of 1.3:1:0.01. The obtained mixed solution was evenly dispersed and poured into a transparent mold (the mold was a pair of glass plates separated by a 1 mm thick silicone plate, and had a cavity inside for accommodating the mixed solution). The mold was exposed to ultraviolet light for 10 h to complete photopolymerization and obtain a polymer.

[0047] (2) The polymer was mixed with the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone and dissolved in dichloromethane to prepare a coating. The coating was spin-coated on the rubber surface and placed in an oven at 60°C for curing for 1 hour to obtain an elastomeric coating.

[0048] In this comparative example, a coating was synthesized by photopolymerization and applied to the rubber surface to form an elastomeric coating. However, it was found that the polymer prepared after complete polymerization by light initiation was difficult to mix evenly with the anti-ultraviolet agent, and the mixed coating could not form an effective bond with the rubber surface. Therefore, in subsequent embodiments of the present invention, the photopolymerization method was abandoned and the thermal polymerization method was used to synthesize the polymer.

[0049] Example 1

[0050] This embodiment is based on a thermal polymerization method to prepare a coating and an anti-ultraviolet coating with waterproof and anti-ultraviolet functions for a rubber surface, which specifically includes the following steps:

[0051] (1) Dissolve 1.3g of methoxyethyl methacrylate, 1g of isobornyl acrylate and 0.01g of thermal initiator ammonium persulfate in 30ml of N,N-dimethylformamide solution, stir to make it evenly dispersed to form a precursor solution, heat the precursor solution to raise its temperature to 60°C and maintain it for 7h of thermal polymerization reaction, and stir throughout the reaction. Add the mixed solution obtained after the reaction dropwise into deionized water to induce polymer precipitation by utilizing the difference in solubility of the polymer in N,N-dimethylformamide and water, and finally remove the supernatant by centrifugation to obtain a solid phase polymer. Dry the obtained solid phase polymer in a vacuum oven at 40°C for later use.

[0052] (2) The dried solid polymer and the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone are mixed in a mass ratio of 2:1 to form a solid material, and then dichloromethane is gradually added to dissolve the solid material. The addition of dichloromethane is stopped immediately after all the solid materials are completely dissolved, thereby forming an anti-ultraviolet coating for coating and curing on the rubber surface.

[0053] (3) The prepared anti-ultraviolet coating was spin-coated on the rubber surface, and then the rubber was placed in an oven at 60 °C and cured for 1 h to obtain an anti-ultraviolet coating (wherein the mass ratio of the solid phase polymer to the anti-ultraviolet agent a:b was 2:1).

[0054] Example 2

[0055] This embodiment is based on a thermal polymerization method to prepare a coating and an anti-ultraviolet coating with waterproof and anti-ultraviolet functions for a rubber surface, which specifically includes the following steps:

[0056] (1) Dissolve 1.3g of methoxyethyl methacrylate, 1g of isobornyl acrylate and 0.01g of thermal initiator ammonium persulfate in 30ml of N,N-dimethylformamide solution, stir to make it evenly dispersed to form a precursor solution, heat the precursor solution to raise its temperature to 60°C and maintain it for 7h of thermal polymerization reaction, and stir throughout the reaction. Add the mixed solution obtained after the reaction dropwise into deionized water to induce polymer precipitation by utilizing the difference in solubility of the polymer in N,N-dimethylformamide and water, and finally remove the supernatant by centrifugation to obtain a solid phase polymer. Dry the obtained solid phase polymer in a vacuum oven at 40°C for later use.

[0057] (2) The dried solid polymer and the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone are mixed in a mass ratio of 3:1 to form a solid material, and then dichloromethane is gradually added to dissolve the solid material. The addition of dichloromethane is stopped immediately after all the solid materials are completely dissolved, thereby forming an anti-ultraviolet coating for coating and curing on the rubber surface.

[0058] (3) The prepared anti-ultraviolet coating was spin-coated on the rubber surface, and then the rubber was placed in an oven at 60 °C and cured for 1 h to obtain an anti-ultraviolet coating (wherein the mass ratio of the solid phase polymer to the anti-ultraviolet agent a:b was 3:1).

[0059] Example 3

[0060] This embodiment is based on a thermal polymerization method to prepare a coating and an anti-ultraviolet coating with waterproof and anti-ultraviolet functions for a rubber surface, which specifically includes the following steps:

[0061] (1) Dissolve 1.3g of methoxyethyl methacrylate, 1g of isobornyl acrylate and 0.01g of thermal initiator ammonium persulfate in 30ml of N,N-dimethylformamide solution, stir to make it evenly dispersed to form a precursor solution, heat the precursor solution to raise its temperature to 60°C and maintain it for 7h of thermal polymerization reaction, and stir throughout the reaction. Add the mixed solution obtained after the reaction dropwise into deionized water to induce polymer precipitation by utilizing the difference in solubility of the polymer in N,N-dimethylformamide and water, and finally remove the supernatant by centrifugation to obtain a solid phase polymer. Dry the obtained solid phase polymer in a vacuum oven at 40°C for later use.

[0062] (2) The dried solid polymer and the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone are mixed in a mass ratio of 4:1 to form a solid material, and then dichloromethane is gradually added to dissolve the solid material. The addition of dichloromethane is stopped immediately after all the solid materials are completely dissolved, thereby forming an anti-ultraviolet coating for coating and curing on the rubber surface.

[0063] (3) The prepared anti-ultraviolet coating was spin-coated on the rubber surface, and then the rubber was placed in an oven at 60 °C and cured for 1 h to obtain an anti-ultraviolet coating (wherein the mass ratio of the solid phase polymer to the anti-ultraviolet agent a:b was 4:1).

[0064] Example 4

[0065] This embodiment is based on a thermal polymerization method to prepare a coating and an anti-ultraviolet coating with waterproof and anti-ultraviolet functions for a rubber surface, which specifically includes the following steps:

[0066] (1) Dissolve 1.3g of methoxyethyl methacrylate, 1g of isobornyl acrylate and 0.01g of thermal initiator ammonium persulfate in 30ml of N,N-dimethylformamide solution, stir to make it evenly dispersed to form a precursor solution, heat the precursor solution to raise its temperature to 60°C and maintain it for 7h of thermal polymerization reaction, and stir throughout the reaction. Add the mixed solution obtained after the reaction dropwise into deionized water to induce polymer precipitation by utilizing the difference in solubility of the polymer in N,N-dimethylformamide and water, and finally remove the supernatant by centrifugation to obtain a solid phase polymer. Dry the obtained solid phase polymer in a vacuum oven at 40°C for later use.

[0067] (2) The dried solid polymer and the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone are mixed in a mass ratio of 5:1 to form a solid material, and then dichloromethane is gradually added to dissolve the solid material. The addition of dichloromethane is stopped immediately after all the solid materials are completely dissolved, thereby forming an anti-ultraviolet coating for coating and curing on the rubber surface.

[0068] (3) The prepared anti-ultraviolet coating was spin-coated on the rubber surface, and then the rubber was placed in an oven at 60 °C and cured for 1 h to obtain an anti-ultraviolet coating (wherein the mass ratio of the solid phase polymer to the anti-ultraviolet agent a:b was 5:1).

[0069] The rubber with anti-ultraviolet coating obtained in Examples 1 to 4 was placed under a 365 nm ultraviolet lamp for 10 h, cut into dog-bone patterns, and subjected to tensile testing using a universal testing machine Instron 5965 at a controlled rate of 60 mm / min. The fracture stress of the rubber prepared under different mass ratios of solid phase polymer to anti-ultraviolet agent a:b was as follows: Figure 1 It can be seen that Examples 1-4 synthesized the anti-ultraviolet rubber coating by thermal polymerization, and the anti-ultraviolet ability was changed by adding anti-ultraviolet agents in different mass proportions, and the anti-ultraviolet effect was significantly improved as the proportion of the anti-ultraviolet agent increased.

[0070] Example 5

[0071] This embodiment uses different coating solvents to prepare anti-ultraviolet coatings and tests their effects on anti-ultraviolet performance, specifically including the following steps:

[0072] (1) Dissolve 1.3g of methoxyethyl methacrylate, 1g of isobornyl acrylate and 0.01g of thermal initiator ammonium persulfate in 30ml of N,N-dimethylformamide solution, stir to make it evenly dispersed to form a precursor solution, heat the precursor solution to raise its temperature to 60°C and maintain it for 7h of thermal polymerization reaction, and stir throughout the reaction. Add the mixed solution obtained after the reaction dropwise into deionized water to induce polymer precipitation by utilizing the difference in solubility of the polymer in N,N-dimethylformamide and water, and finally remove the supernatant by centrifugation to obtain a solid phase polymer. Dry the obtained solid phase polymer in a vacuum oven at 40°C for later use.

[0073] (2) The dried solid polymer and the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone are mixed in a mass ratio of 2:1 to form a solid material, and then N,N-dimethylformamide is gradually added to dissolve the solid material. The addition of N,N-dimethylformamide is stopped immediately after all the solid materials are completely dissolved, thereby forming an anti-ultraviolet coating for coating and curing on the rubber surface.

[0074] (3) The prepared anti-ultraviolet coating was spin-coated on the rubber surface, and then the rubber was placed in an oven at 60 °C and cured for 1 h to obtain an anti-ultraviolet coating (wherein the mass ratio of the solid phase polymer to the anti-ultraviolet agent a:b was 2:1).

[0075] Compared with Example 1, the difference between this example and Example 1 is that the coating solvent used to dissolve the solid phase material uses N,N-dimethylformamide instead of dichloromethane CH2Cl2 in Example 1. The rubber with anti-ultraviolet coating obtained by the two coating solvents was placed under 365 nm ultraviolet light for 10 hours, cut into dog-bone patterns, and tensile tested using a universal testing machine Instron5965, with the tensile rate controlled at 60 mm / min. The tensile curves obtained were compared as follows: Figure 2 As shown. This example tests the effect of different solvents on the anti-ultraviolet performance by selecting them for dissolution. The experimental results show that both N, N-dimethylformamide and CH2Cl2 solvents can be used to prepare anti-ultraviolet coatings, and using N, N-dimethylformamide instead of dichloromethane for dissolution will not reduce its anti-ultraviolet performance.

[0076] Example 6

[0077] The above embodiments can prepare the coating and anti-ultraviolet coating for rubber surface with waterproof and anti-ultraviolet function. In this embodiment, a more detailed performance test is further conducted based on the coating and anti-ultraviolet coating prepared in Example 1. The specific test process is as follows:

[0078] 1. UV transmittance test

[0079] (1) Select two glass plates of 5 cm × 5 cm × 0.5 cm, and spin-coat the anti-ultraviolet coating obtained in Example 1 on the surface of the glass plates. Place the glass plates in a 60 °C oven and cure for 1 hour to obtain a glass plate A1 with the target coating. Take another uncoated identical glass plate and mark it as A2. Use ultraviolet rays with a wavelength of 200-800 nm for irradiation. Based on the transmittance data of A1 and A2 under ultraviolet irradiation, calculate the ultraviolet transmittance of different wavelengths as follows Figure 3 shown.

[0080] The results of this example show that the prepared anti-ultraviolet coating has a transmittance of nearly 100% in the visible light band, indicating that it is very transparent, but the ultraviolet transmittance for the UVA band of 320-420 nm is 0%, and the ultraviolet transmittance for the UVB band of 300-320 nm is less than 20%, and it has a good protection effect for ultraviolet rays of 300-420 nm.

[0081] 2. Contact angle test

[0082] Two pieces of rubber with a size of 5 cm × 5 cm × 0.5 cm were selected, and the anti-ultraviolet coating obtained in Example 1 was spin-coated on the rubber surface. The rubber was placed in a 60 °C oven and cured for 1 hour to obtain rubber B1 with the target coating. Another piece of the same rubber without coating was taken and marked as B2. Then, the contact angle of water on the coating and rubber was measured based on the two rubber materials. The images captured during the process are shown in FIG. Figure 4 As shown, Figure 4 The left and right images in the middle are the contact angle results of the uncoated rubber and the coated rubber, respectively.

[0083] This embodiment calculates Figure 4 The contact angle of the water droplet in the figure is about 95° for B1 and about 105° for B2, indicating that the anti-ultraviolet coating prepared by the present invention is hydrophobic and dense, and can effectively prevent water penetration.

[0084] 3. UV aging test

[0085] Take 4 rubber pieces of 10 cm × 10 cm × 0.05 cm, and spin-coat the anti-ultraviolet coating obtained in Example 1 on the rubber surface. Place the rubber in a 60°C oven and cure it for 1 hour to obtain multiple rubber specimens with the target coating. Two of the rubber specimens are coated with the coating and marked as C1 and C2, and the other two are marked as W1 and W2. C1 and W1 are placed in a 365nm ultraviolet environment for 10 hours, and the other two C2 and W2 are not exposed to ultraviolet radiation and serve as controls. Use a universal testing machine Instron5965 for tensile testing, and the tensile rate is 60 mm / min. The results are as follows. Figure 5 As shown, the measured fracture stresses of C1, C2, W1, and W2 are 17.88MPa, 19.16MPa, 10.10MPa, and 27.01MPa, respectively.

[0086] This example shows that the rubber ages after 10 hours of ultraviolet irradiation, and the mechanical properties show a significant decline. The introduction of the anti-ultraviolet coating prepared by the present invention can effectively reduce the effect of ultraviolet rays on rubber aging.

[0087] 4. Electron microscope microscopic image shooting:

[0088] Two pieces of rubber with a size of 10 cm × 10 cm × 0.05 cm were selected and the microscopic photos were taken by scanning electron microscope before and after coating. Figure 6 As shown in a), the microscopic photograph of the uncoated rubber is as follows Figure 6 As shown in (b), a very clear boundary line can be observed between the coating and the rubber.

[0089] The above-described embodiments are only some preferred implementations of the present invention, but are not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A method for preparing a coating with waterproof and UV-resistant functions for rubber surface, characterized in that: include: S1: a precursor solution is formed by mixing methoxyethyl methacrylate, isobornyl acrylate, thermal initiator ammonium persulfate and an organic solvent, the precursor solution is heated to perform a thermal polymerization reaction, and the resulting mixed solution is dropped into water to induce precipitation of the polymer product, and finally a solid phase polymer is obtained by centrifugation; S2: Mixing the dried solid polymer with the anti-ultraviolet agent 2-hydroxy-4-methoxybenzophenone to form a solid material, and then gradually adding a coating solvent that does not corrode the rubber but can dissolve the solid material, until all the solid materials are completely dissolved to form an anti-ultraviolet coating for coating and curing on the rubber surface; In the precursor solution, the mass ratio of methoxyethyl methacrylate, isobornyl acrylate and thermal initiator is (1.2-1.4): 1: (0.01-0.02); The reaction temperature of the thermal polymerization reaction is 50-70°C, the reaction time is 6-8 hours, and the reaction needs to be stirred throughout the process; The organic solvent is N,N-dimethylformamide; The coating solvent is dichloromethane or N,N-dimethylformamide; In the solid phase material, the mass ratio of the solid phase polymer to the anti-ultraviolet agent is (2-5):

1.

2. The method for preparing a coating with waterproof and UV-resistant functions for rubber surface according to claim 1, characterized in that: The solid phase polymer needs to be dried in an environment of 35-45°C before being mixed with the anti-ultraviolet agent.

3. A coating with waterproof and UV resistance for rubber surface, characterized in that: The coating is prepared according to the coating preparation method as claimed in claim 1 or 2.

4. A method for preparing an anti-ultraviolet coating for rubber, characterized in that: After the anti-ultraviolet coating is prepared according to the coating preparation method as claimed in claim 1 or 2, it is coated on the rubber surface and cured at a temperature of 55-65°C to form an anti-ultraviolet coating on the rubber surface.

5. The method for preparing the anti-ultraviolet coating for rubber according to claim 4, characterized in that: The method of applying the anti-ultraviolet coating on the rubber surface is spin coating or brush coating.

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