An anti-ultraviolet modified epoxy resin and its preparation method

Abstract

The present invention discloses an anti-ultraviolet modified epoxy resin and a preparation method thereof, which relates to the technical field of preparation methods of functional materials. The modified epoxy resin includes hydroxyl groups, benzotriazole groups, and siloxane groups. The preparation method includes: taking epoxy resin, 2-hydroxyethyl methacrylate, and a catalyst, mixing them, heating for reaction, cooling to room temperature after completion, and separating the product; mixing the obtained product with 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and a catalyst, heating for reaction, cooling and separating the product; mixing the obtained product with γ-aminopropyltriethoxysilane and a catalyst, heating for reaction, cooling and separating the product to obtain the anti-ultraviolet modified epoxy resin. The modified epoxy resin prepared by the above method is used to prepare coatings, and the coatings have excellent anti-ultraviolet performance.

Description

Technical Field

[0001] The present invention provides an anti-ultraviolet modified epoxy resin and a preparation method thereof, relating to the technical field of preparation methods of functional materials. Background Art

[0002] Epoxy resin, as a kind of polymer, has shown its excellent properties in many fields, especially widely used in coatings, adhesives, composite materials, etc. However, this powerful material also has its weakness - sensitivity to ultraviolet light. This is mainly because the ether bond energy in the main chain of epoxy resin is relatively weak, and ultraviolet light can break it, thus affecting the performance and service life of the material.

[0003] In outdoor applications, such as architectural coatings, automotive paints and other fields, this defect of epoxy resin is particularly obvious. Long-term ultraviolet irradiation will cause the material surface to turn yellow, lose luster, powder, crack, etc. This not only affects the aesthetics of the product, but may also endanger its structural safety.

[0004] To solve this problem, scientific researchers have carried out a large number of studies and attempts. At present, there are mainly two methods to overcome the ultraviolet sensitivity of epoxy resin: one is to add ultraviolet absorbers, and the other is to carry out chemical modification.

[0005] Ultraviolet absorbers can effectively absorb ultraviolet light and convert it into heat energy for release, thereby protecting the main chain of epoxy resin from being damaged by ultraviolet light. However, the effect of this method is limited by the addition amount and dispersion uniformity of the absorber. Excessive addition may affect the original properties of epoxy resin, while uneven dispersion may lead to non-uniform protection effect.

[0006] Chemical modification is to change the molecular structure of epoxy resin to enhance its ability to resist ultraviolet light. Although this method can fundamentally solve the problem, the technical difficulty and cost in the modification process are relatively high. At the same time, the modified epoxy resin may need to re-evaluate its various properties to ensure meeting the application requirements.

[0007] Although the above two methods have alleviated the ultraviolet sensitivity problem of epoxy resin to a certain extent, there are still many challenges. For example, how to find an ultraviolet absorber that can effectively protect epoxy resin without affecting its original properties; how to achieve the chemical modification of epoxy resin on the premise of ensuring cost-effectiveness; and how to accurately evaluate the long-term performance of the modified epoxy resin in various complex environments, etc.

[0008] With the progress of technology and the continuous emergence of new material technologies, we have reason to believe that the problem of ultraviolet sensitivity of epoxy resin will eventually be effectively solved. This will not only greatly expand the application scope and service life of epoxy resin, but also bring huge economic and social benefits to related industries. As a versatile polymer material, epoxy resin occupies an important position in the national economy. The research and improvement of its ultraviolet sensitivity is not only a challenge to materials science, but also the key to promoting the sustainable and healthy development of related industries. Summary of the Invention

[0009] To solve the above problems, the present invention provides a method for improving the ultraviolet resistance of epoxy resin by chemically grafting and modifying epoxy resin. The specific scheme is as follows:

[0010] An ultraviolet-resistant modified epoxy resin, wherein the modified epoxy resin includes hydroxyl groups, benzotriazole groups, and siloxane groups.

[0011] The present invention also provides a preparation method for the above ultraviolet-resistant modified epoxy resin, which includes the following steps:

[0012] S1. Take epoxy resin, hydroxyethyl methacrylate, and a catalyst, mix them, heat them for reaction, cool to room temperature after completion, and separate the product;

[0013] S2. Mix the product obtained in step S1 with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and a catalyst, heat for reaction, and separate the product after cooling;

[0014] S3. Mix the product obtained in step S2 with γ-aminopropyltriethoxysilane and a catalyst, heat for reaction, and separate the product after cooling to obtain the ultraviolet-resistant modified epoxy resin.

[0015] Preferably, the catalyst in step S1 is triphenylphosphine.

[0016] Preferably, the mass ratio of the epoxy resin, hydroxyethyl methacrylate, and the catalyst in step S1 is 100:(10 - 15):(0.5 - 1.0).

[0017] Preferably, the reaction temperature in step S1 is 90 - 105°C, and the time is 3 - 4 h.

[0018] Preferably, the separation of the product in step S1 includes: adding deionized water for emulsification after cooling to room temperature, and removing unreacted monomers and the catalyst by centrifugation or filtration to obtain the product.

[0019] Preferably, the addition amount of the deionized water is 2 - 2.5 times the mass of the epoxy resin.

[0020] Preferably, the catalyst in step S2 is dimethylaminopyridine.

[0021] Preferably, the mass ratio of the product obtained in S1 to 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and the catalyst in step S2 is 100:(5-8):(0.3-0.5).

[0022] Preferably, the reaction temperature in step S2 is 80-85 °C, and the reaction time is 2-4 h.

[0023] Preferably, the separation of the product in step S2 includes: washing with ethanol or acetone and then drying to remove the solvent.

[0024] Preferably, the catalyst in step S3 is glacial acetic acid, and the dosage is 1-2 wt% of the product obtained in step S2.

[0025] Preferably, the mass ratio of the product obtained in step S2 to γ-aminopropyltriethoxysilane in step S3 is 100:(3-5).

[0026] Preferably, the reaction temperature in step S3 is 65-70 °C, and the reaction time is 1.5-2 h.

[0027] Preferably, the separation of the product in step S3 includes: washing the product with methanol or ethanol and then drying.

[0028] Advantages of the present invention:

[0029] Introduction of benzotriazole group: Benzotriazole is an effective ultraviolet absorber. When ultraviolet light irradiates on the material, the benzotriazole group can absorb the ultraviolet light and convert it into heat energy, thus preventing the destruction of the epoxy resin main chain by ultraviolet light. In this way, the benzotriazole group can effectively protect the epoxy resin from ultraviolet degradation.

[0030] Introduction of siloxane group and hydroxyl group: In our previous research and development, the introduction of siloxane group is usually used to enhance the weather resistance and waterproofness of epoxy resin. The siloxane group can form a waterproof barrier, reducing the erosion of water and oxygen on the epoxy resin, thus prolonging its service life. In addition, the siloxane group can also improve the flexibility and impact resistance of the epoxy resin, making it more durable. The introduction of hydroxyl group is usually used to enhance its adhesion, heat resistance and chemical resistance. However, in the present invention, we found that on the premise of introducing the benzotriazole group, the simultaneous introduction of siloxane group and hydroxyl group can greatly enhance the ultraviolet resistance of the modified epoxy resin. Detailed implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the present invention. The preferred implementation methods and materials described herein are only for demonstration purposes and do not limit the content of this application.

[0033] The experimental methods in the following embodiments are all conventional methods unless otherwise specified. The test materials used in the following embodiments are all obtained from commercial channels unless otherwise specified.

[0034] Reagents:

[0035] Epoxy resin: E-44 type, e-44 bisphenol A type epoxy resin, Baichen Insulating Materials Co., Ltd., Laizhou City, Shandong Province;

[0036] 2-Hydroxyethyl methacrylate (HEMA): Guangzhou Kafen Biotechnology Co., Ltd.;

[0037] Triphenylphosphine (TPP): Wuhan Beiguofeng Chemical Co., Ltd.;

[0038] 2-(2'-Hydroxy-5'-methylphenyl) benzotriazole: Benzotriazole ultraviolet absorber (UV-P), Chengdu Huaxia Chemical Reagent Co., Ltd.;

[0039] Dimethylaminopyridine DMAP: Hefei Yihang New Materials Co., Ltd.;

[0040] γ-Aminopropyltriethoxysilane (APTES): Shanghai Haling Biotechnology Co., Ltd.

[0041] Example 1 Preparation of anti-ultraviolet modified epoxy resin:

[0042] S1. Take epoxy resin, 2-hydroxyethyl methacrylate and a catalyst, mix them, heat them for reaction, and after completion, cool to room temperature and separate the product;

[0043] S2. Mix the product obtained in step S1 with 2-(2'-hydroxy-5'-methylphenyl) benzotriazole and a catalyst, heat and react, and separate the product after cooling;

[0044] S3. The product obtained in step S2 is mixed with γ-aminopropyltriethoxysilane and a catalyst, heated for reaction, and after cooling, the product is separated to obtain the ultraviolet-resistant modified epoxy resin.

[0045] The catalyst described in step S1 is triphenylphosphine.

[0046] The mass ratio of the epoxy resin, hydroxyethyl methacrylate, and catalyst described in step S1 is 100:15:1.0.

[0047] The reaction temperature described in step S1 is 105 °C, and the time is 4 h.

[0048] The separation of the product described in step S1 includes: adding deionized water for emulsification after cooling to room temperature, and removing unreacted monomers and catalysts by centrifugation or filtration to obtain the product.

[0049] The addition amount of the deionized water is 2.5 times the mass of the epoxy resin.

[0050] The catalyst described in step S2 is dimethylaminopyridine.

[0051] The mass ratio of the product obtained in step S1 and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and the catalyst described in step S2 is 100:8:0.5.

[0052] The reaction temperature described in step S2 is 85 °C, and the reaction time is 4 h.

[0053] The separation of the product described in step S2 includes: washing with ethanol and then drying to remove the solvent.

[0054] The catalyst described in step S3 is glacial acetic acid, and the dosage is 2 wt% of the product obtained in step S2.

[0055] The mass ratio of the product obtained in step S2 and γ-aminopropyltriethoxysilane described in step S3 is 100:5.

[0056] The reaction temperature described in step S3 is 70 °C, and the reaction time is 2 h.

[0057] The separation of the product described in step S3 includes: washing the product with ethanol and then drying.

[0058] Preparation of the ultraviolet-resistant modified epoxy resin in Example 2:

[0059] S1. Take the epoxy resin, hydroxyethyl methacrylate, and catalyst, mix them, heat for reaction, and after cooling to room temperature, separate the product;

[0060] S2. The product obtained in step S1 is mixed with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and a catalyst, heated for reaction, and after cooling, the product is separated;

[0061] S3. The product obtained in step S2 is mixed with γ-aminopropyltriethoxysilane and a catalyst, heated for reaction, and after cooling, the product is separated to obtain the ultraviolet-resistant modified epoxy resin.

[0062] The catalyst described in step S1 is triphenylphosphine.

[0063] The mass ratio of the epoxy resin, hydroxyethyl methacrylate and the catalyst described in step S1 is 100:10:0.5.

[0064] The reaction temperature described in step S1 is 90 °C and the time is 3 h.

[0065] The separation of the product described in step S1 includes: after cooling to room temperature, deionized water is added for emulsification, and the unreacted monomers and catalyst are removed by centrifugation or filtration to obtain the product.

[0066] The addition amount of the deionized water is 2.5 times the mass of the epoxy resin.

[0067] The catalyst described in step S2 is dimethylaminopyridine.

[0068] The mass ratio of the product obtained in step S1 to 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and the catalyst described in step S2 is 100:5:0.3.

[0069] The reaction temperature described in step S2 is 80 °C and the reaction time is 2 h.

[0070] The separation of the product described in step S2 includes: washing with ethanol and then drying to remove the solvent.

[0071] The catalyst described in step S3 is glacial acetic acid, and the dosage is 1 wt% of the product obtained in step S2.

[0072] The mass ratio of the product obtained in step S2 to γ-aminopropyltriethoxysilane described in step S3 is 100:3.

[0073] The reaction temperature described in step S3 is 65 °C and the reaction time is 1.5 h.

[0074] The separation of the product described in step S3 includes: washing the product with ethanol and then drying.

[0075] Preparation of the ultraviolet-resistant modified epoxy resin in Example 3:

[0076] S1. Take the epoxy resin, hydroxyethyl methacrylate and the catalyst, mix them, heat for reaction, and after completion, cool to room temperature and separate the product;

[0077] S2. The product obtained in step S1 is mixed with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and the catalyst, heated for reaction, and after cooling, the product is separated;

[0078] S3. The product obtained in step S2 is mixed with γ-aminopropyltriethoxysilane and a catalyst, heated for reaction, and after cooling, the product is separated to obtain the ultraviolet-resistant modified epoxy resin.

[0079] The catalyst described in step S1 is triphenylphosphine.

[0080] The mass ratio of the epoxy resin, hydroxyethyl methacrylate, and catalyst described in step S1 is 100:13:0.8.

[0081] The reaction temperature described in step S1 is 100 °C, and the time is 4 h.

[0082] The separation of the product described in step S1 includes: adding deionized water for emulsification after cooling to room temperature, and removing unreacted monomers and the catalyst by centrifugation or filtration to obtain the product.

[0083] The addition amount of the deionized water is 2.5 times the mass of the epoxy resin.

[0084] The catalyst described in step S2 is dimethylaminopyridine.

[0085] The mass ratio of the product obtained in step S1 and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and the catalyst described in step S2 is 100:7:0.4.

[0086] The reaction temperature described in step S2 is 80 °C, and the reaction time is 4 h.

[0087] The separation of the product described in step S2 includes: washing with ethanol and then drying to remove the solvent.

[0088] The catalyst described in step S3 is glacial acetic acid, and the dosage is 1 wt% of the product obtained in step S2.

[0089] The mass ratio of the product obtained in step S2 and γ-aminopropyltriethoxysilane described in step S3 is 100:4.

[0090] The reaction temperature described in step S3 is 70 °C, and the reaction time is 1.5 h.

[0091] The separation of the product described in step S3 includes: washing the product with ethanol and then drying.

[0092] Preparation of the modified epoxy resin in Comparative Example 1 (without introducing hydroxyl groups):

[0093] S1. Take the epoxy resin, heat it and then cool it.

[0094] S2. The product obtained in step S1 is mixed with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and a catalyst, heated for reaction, and after cooling, the product is separated.

[0095] S3. The product obtained in step S2 is mixed with γ-aminopropyltriethoxysilane and a catalyst, heated for reaction, and after cooling, the product is separated to obtain the anti-ultraviolet modified epoxy resin.

[0096] The heating temperature in step S1 is 100 °C and the time is 4 h.

[0097] The catalyst in step S2 is dimethylaminopyridine.

[0098] The mass ratio of the product obtained in step S1 to 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and the catalyst in step S2 is 100:7:0.4.

[0099] The reaction temperature in step S2 is 80 °C and the reaction time is 4 h.

[0100] The separation of the product in step S2 includes: washing with ethanol and then drying to remove the solvent.

[0101] The catalyst in step S3 is glacial acetic acid and the dosage is 1 wt% of the product obtained in step S2.

[0102] The mass ratio of the product obtained in step S2 to γ-aminopropyltriethoxysilane in step S3 is 100:4.

[0103] The reaction temperature in step S3 is 70 °C and the reaction time is 1.5 h.

[0104] The separation of the product in step S3 includes: washing the product with ethanol and then drying.

[0105] Preparation of the modified epoxy resin in Comparative Example 2 (without introducing benzotriazole group):

[0106] S1. Take epoxy resin, 2-hydroxyethyl methacrylate and a catalyst, mix them and heat for reaction. After completion, cool to room temperature and separate the product;

[0107] S2. Heat the product obtained in step S1 and then cool it;

[0108] S3. The product obtained in step S2 is mixed with γ-aminopropyltriethoxysilane and a catalyst, heated for reaction, and after cooling, the product is separated to obtain the anti-ultraviolet modified epoxy resin.

[0109] The catalyst in step S1 is triphenylphosphine.

[0110] The mass ratio of the epoxy resin, 2-hydroxyethyl methacrylate and the catalyst in step S1 is 100:13:0.8.

[0111] The reaction temperature in step S1 is 100 °C and the time is 4 h.

[0112] The separated product described in step S1 includes: adding deionized water for emulsification after cooling to room temperature, and removing unreacted monomers and catalysts by centrifugation or filtration to obtain the product.

[0113] The added amount of the deionized water is 2.5 times the mass of the epoxy resin.

[0114] The heating temperature described in step S2 is 80 °C, and the time is 4 h.

[0115] The catalyst described in step S3 is glacial acetic acid, and the dosage is 1 wt% of the product obtained in step S2.

[0116] The mass ratio of the product obtained in step S2 to γ-aminopropyltriethoxysilane described in step S3 is 100:4.

[0117] The reaction temperature described in step S3 is 70 °C, and the reaction time is 1.5 h.

[0118] The separated product described in step S3 includes: washing the product with ethanol and then drying.

[0119] Preparation of the modified epoxy resin in Comparative Example 3 (without introducing siloxane groups):

[0120] S1. Take epoxy resin, hydroxyethyl methacrylate, and a catalyst, mix them, and heat for reaction. After completion, cool to room temperature and separate the product;

[0121] S2. Mix the product obtained in step S1 with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and a catalyst, heat for reaction, and separate the product after cooling;

[0122] S3. Heat the product obtained in step S2 and then cool.

[0123] The catalyst described in step S1 is triphenylphosphine.

[0124] The mass ratio of the epoxy resin, hydroxyethyl methacrylate, and the catalyst described in step S1 is 100:13:0.8.

[0125] The reaction temperature described in step S1 is 100 °C, and the time is 4 h.

[0126] The separated product described in step S1 includes: adding deionized water for emulsification after cooling to room temperature, and removing unreacted monomers and catalysts by centrifugation or filtration to obtain the product.

[0127] The added amount of the deionized water is 2.5 times the mass of the epoxy resin.

[0128] The catalyst described in step S2 is dimethylaminopyridine.

[0129] The mass ratio of the product obtained in S1 described in step S2, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, and the catalyst is 100:7:0.4.

[0130] The reaction temperature described in step S2 is 80 °C, and the reaction time is 4 h.

[0131] The separated product described in step S2 includes: washing with ethanol and then drying to remove the solvent.

[0132] The heating temperature described in step S3 is 70 °C, and the time is 1.5 h.

[0133] Preparation of the modified epoxy resin in Comparative Example 4 (only introducing hydroxyl groups):

[0134] Take epoxy resin, 2-hydroxyethyl methacrylate, and a catalyst, mix them, heat for reaction, and after completion, cool to room temperature and separate the product.

[0135] The catalyst described in step S1 is triphenylphosphine.

[0136] The mass ratio of the epoxy resin, 2-hydroxyethyl methacrylate, and the catalyst described in step S1 is 100:13:0.8.

[0137] The reaction temperature is 100 °C, and the time is 4 h.

[0138] The separated product includes: adding deionized water for emulsification after cooling to room temperature, and removing unreacted monomers and the catalyst by centrifugation or filtration to obtain the product.

[0139] The added amount of deionized water is 2.5 times the mass of the epoxy resin.

[0140] Preparation of the modified epoxy resin in Comparative Example 5 (only introducing benzotriazole groups):

[0141] Take epoxy resin, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, and a catalyst, mix them, heat for reaction, and after cooling, separate the product.

[0142] The catalyst is dimethylaminopyridine.

[0143] The mass ratio of the epoxy resin, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, and the catalyst is 100:7:0.4.

[0144] The reaction temperature is 80 °C, and the reaction time is 4 h.

[0145] The separated product includes: washing with ethanol and then drying to remove the solvent.

[0146] Preparation of the modified epoxy resin in Comparative Example 6 (only introducing siloxane groups):

[0147] Mix epoxy resin, γ-aminopropyltriethoxysilane, and a catalyst, heat the mixture for reaction, and after cooling, separate the product to obtain anti-ultraviolet modified epoxy resin.

[0148] The catalyst is glacial acetic acid, and its dosage is 1 wt% of the product obtained in step S2.

[0149] The mass ratio of the epoxy resin to γ-aminopropyltriethoxysilane is 100:4.

[0150] The reaction temperature is 70 °C, and the reaction time is 1.5 h.

[0151] The separated product includes: washing the product with ethanol and then drying it.

[0152] Perform performance tests on the products obtained from all the above examples and comparative examples:

[0153] Respectively take the products obtained from the examples and comparative examples, prepare coatings according to the following formula and coat them on the substrate, and detect after thorough drying:

[0154] Modified epoxy resin: 100 parts

[0155] Ethylenediamine: 4 parts

[0156] Dioctyl phthalate (DOP): 5 parts

[0157] Absolute ethanol: 10 parts

[0158] Organosilicon defoamer SAG-622: 0.05 part

[0159] Leveling agent BYK-333: 0.3 part

[0160] Blank control: Use E-44 type epoxy resin to replace the above modified epoxy resin to prepare the coating.

[0161] According to GB / T 14522-93 "Test Method for Resistance to Ultraviolet Radiation of Coating Paints - Epoxy Coatings", detect the anti-ultraviolet performance of the epoxy resin coating. The detailed operation is as follows:

[0162] Substrate preparation: Select an appropriate steel plate as the substrate, and ensure that its surface is flat, clean, and free of oil stains.

[0163] Coating application: Use the spraying method to evenly apply the epoxy resin coating on the substrate to form a coating with a thickness of 0.3 mm.

[0164] Coating drying: Place the applied coating in a constant temperature and humidity environment and let it dry and cure naturally.

[0165] Prepare an ultraviolet aging test chamber, which can simulate ultraviolet radiation in the natural environment and control parameters such as temperature and humidity at the same time. Put the coated and dried coating samples into the ultraviolet aging test chamber to ensure that the surface of the samples can uniformly receive ultraviolet radiation. The ultraviolet radiation intensity should be controlled between 0.35 W / m2 and 0.55 W / m2, the temperature is set at (60±3) °C, the relative humidity is set at (65±5)%, and the test time is 800 h. Start the ultraviolet aging test chamber and begin the test. During the test, regularly record the changes in the coating, such as color change, gloss change, etc. After the test, turn off the ultraviolet aging test chamber and take out the samples for subsequent testing.

[0166] The main detection parameters include the change in the gloss of the coating surface, the change in the adhesion of the coating, the change in hardness, and whether there are cracking and peeling phenomena on the coating. Among them, the hardness is detected according to ASTM D3363-20 (pencil hardness test method). The adhesion is detected according to GB / T9286-1998 "Cross-cut test for paints and varnishes films". The obtained mechanical property test results are shown in Table 1, and the gloss test results are shown in Table 2.

[0167] Table 1 Test results of mechanical parameters of each sample

[0168]

[0169] Table 2 Test results of gloss of each sample

[0170]

[0171]

[0172] It can be seen from the test results that the modified epoxy resin provided by the present invention has excellent ultraviolet resistance. The introduction of benzotriazole groups directly improves the ultraviolet resistance of the resin, while the introduction of siloxane groups and hydroxyl groups may optimize the ultraviolet resistance by affecting the overall structure of the resin. Benzotriazole is a known ultraviolet absorber, and its molecular structure can absorb ultraviolet light of specific wavelengths. When ultraviolet light irradiates the material, the benzotriazole groups absorb the ultraviolet light and convert it into heat energy, thus reducing the direct damage of the ultraviolet light to the main chain of the epoxy resin. In this way, the benzotriazole groups play the role of "light stabilizer" to protect the epoxy resin from ultraviolet degradation. Siloxane groups are usually used to improve the flexibility and impact resistance of epoxy resins. In the present invention, the siloxane groups may also have a certain synergistic effect with the hydroxyl groups and benzotriazole groups, further enhancing the ultraviolet resistance of the modified epoxy resin. Hydroxyl groups are usually used to enhance the adhesion, heat resistance and chemical resistance of epoxy resins. In the present invention, the introduction of hydroxyl groups may contribute to the cross-linking between epoxy resin molecules, thus forming a more compact and strong molecular network. Such a molecular network may better fix the benzotriazole groups and siloxane groups, making their distribution in the epoxy resin more uniform, thereby improving the overall ultraviolet resistance; it may also have a certain synergistic effect with the siloxane groups and benzotriazole groups, further enhancing the ultraviolet resistance of the modified epoxy resin. It can be seen from the gloss loss rate results that the generation of this synergistic effect must occur when the hydroxyl groups and siloxane groups act on the epoxy resin modified with benzotriazole groups at the same time.

[0173] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made therein without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

[0174] The above description of the present invention and its embodiments is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual application is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and design similar ways and embodiments without creative work without departing from the gist of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. An anti-ultraviolet modified epoxy resin, characterized in that: The modified epoxy resin includes hydroxyl groups, benzotriazole groups, and siloxane groups. The preparation method of the ultraviolet-resistant modified epoxy resin includes the following steps: S1. Take epoxy resin, hydroxyethyl methacrylate, and a catalyst, mix them, heat for reaction, cool to room temperature after completion, and separate the product; S2. Mix the product obtained in step S1 with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and a catalyst, heat for reaction, and separate the product after cooling; S3. Mix the product obtained in step S2 with γ-aminopropyltriethoxysilane and a catalyst, heat for reaction, and separate the product after cooling to obtain the ultraviolet-resistant modified epoxy resin; Among them, the catalyst in step S1 is triphenylphosphine; the mass ratio of the epoxy resin, hydroxyethyl methacrylate, and the catalyst in step S1 is 100:(10 - 15):(0.5 - 1.0); the mass ratio of the product obtained in step S1, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, and the catalyst in step S2 is 100:(5 - 8):(0.3 - 0.5); the mass ratio of the product obtained in step S2 and γ-aminopropyltriethoxysilane in step S3 is 100:(3 - 5).

2. The preparation method of the ultraviolet-resistant modified epoxy resin according to claim 1, characterized in that: It includes the following steps: S1. Take epoxy resin, hydroxyethyl methacrylate, and a catalyst, mix them, heat for reaction, cool to room temperature after completion, and separate the product; S2. Mix the product obtained in step S1 with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and a catalyst, heat for reaction, and separate the product after cooling; S3. Mix the product obtained in step S2 with γ-aminopropyltriethoxysilane and a catalyst, heat for reaction, and separate the product after cooling to obtain the ultraviolet-resistant modified epoxy resin; Among them, the catalyst in step S1 is triphenylphosphine; the mass ratio of the epoxy resin, hydroxyethyl methacrylate, and the catalyst in step S1 is 100:(10 - 15):(0.5 - 1.0); the mass ratio of the product obtained in step S1, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, and the catalyst in step S2 is 100:(5 - 8):(0.3 - 0.5); the mass ratio of the product obtained in step S2 and γ-aminopropyltriethoxysilane in step S3 is 100:(3 - 5).

3. The preparation method of the ultraviolet-resistant modified epoxy resin according to claim 2, characterized in that: The reaction temperature in step S1 is 90 - 105 °C, and the time is 3 - 4 h.

4. The preparation method of the ultraviolet-resistant modified epoxy resin according to claim 2 is characterized in that: The catalyst in step S2 is dimethylaminopyridine.

5. The preparation method of the ultraviolet-resistant modified epoxy resin according to claim 2, characterized in that: The reaction temperature in step S2 is 80 - 85 °C, and the reaction time is 2 - 4 h.

6. The preparation method of the ultraviolet-resistant modified epoxy resin according to claim 2, characterized in that: The catalyst in step S3 is glacial acetic acid, and the dosage is 1 - 2 wt% of the product obtained in step S2.

7. The preparation method of the ultraviolet-resistant modified epoxy resin according to claim 2, wherein: The reaction temperature in step S3 is 65 - 70 °C, and the reaction time is 1.5 - 2 h.

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