A uv-curable low-temperature weatherable coating, a modified alkyd resin and a method for preparing the same

Abstract

The application relates to the technical field of paint, in particular to a UV-cured low-temperature weather-resistant paint, a modified alkyd resin and a preparation method thereof.A modified alkyd resin comprises 20-40 parts of alkyd resin, 5-8 parts of epoxy silane, 10-15 parts of unsaturated dibasic organic acid and 0.1-0.3 parts of a catalyst; and the preparation method is as follows: the epoxy silane, the unsaturated dibasic organic acid and the catalyst are stirred and mixed, then the alkyd resin is added, and stirring and mixing are conducted to obtain the modified alkyd resin.The modified alkyd resin can be used for preparing the UV-cured low-temperature weather-resistant paint, and has the characteristics of low cost, fast curing speed, high weather resistance of paint film and strong solvent resistance of paint film.

Description

Technical Field

[0001] This application relates to the field of coating technology, and more specifically, to a UV-curable low-temperature weather-resistant coating, a modified alkyd resin, and a method for preparing the same. Background Technology

[0002] UV coatings are typically made from oligomers, reactive diluents, photoinitiators, and additives, and then cured by UV radiation. They are characterized by high strength, high hardness, high abrasion resistance, and high gloss, and are widely used in industries such as flooring, wooden furniture, plastics, motorcycles, and automobiles.

[0003] However, because plastics, motorcycles, and automobiles are used in outdoor environments, the coatings applied to them are easily affected by sunlight, rain, and other factors, leading to aging and peeling. Although UV coatings prepared using fluoropolymers as oligomers currently have excellent weather resistance, the high price of fluoropolymers limits their use.

[0004] Therefore, there is an urgent need for a UV coating with good weather resistance and low cost. Summary of the Invention

[0005] To improve the weather resistance and reduce the cost of UV coatings, this application provides a UV-curable low-temperature weather-resistant coating, a modified alkyd resin, and a method for preparing the same.

[0006] In a first aspect, this application provides a modified alkyd resin, employing the following technical solution:

[0007] A modified alkyd resin comprises the following raw materials in parts by weight:

[0008] 20-40 parts of alkyd resin;

[0009] 5-8 parts of epoxy silane;

[0010] 10-15 parts of unsaturated dibasic organic acids;

[0011] Catalyst 0.1-0.3 parts.

[0012] By adopting the above technical solution, under the catalytic conditions of the catalyst, epoxy silanes form silanols that react with unsaturated dicarboxylic acids. The resulting mixture contains long-chain alkyl structures, which improves the compatibility between the mixture and alkyd resins. This facilitates the ring-opening reaction between the epoxy groups in the mixture and the hydroxyl and / or carboxyl groups in the alkyd resins and unsaturated dicarboxylic acids, introducing silicon-carbon bonds, silicon-oxygen bonds, and unsaturated carbon-carbon double bonds into the alkyd resins.

[0013] On the one hand, the introduction of silicon-carbon and silicon-oxygen bonds through grafting provides high heat resistance, and the silicon-oxygen bonds, with their high bond energy, are less prone to breakage when absorbing ultraviolet light. Therefore, the paint film formed by crosslinking modified alkyd resin under photoinitiator excitation exhibits a dense structure, high strength, and strong heat resistance, which is beneficial for improving the weather resistance of the paint film. On the other hand, due to the good compatibility between the mixture and the alkyd resin, the alkyd resin can be uniformly dispersed in the mixture, and silicon-carbon, silicon-oxygen, and carbon-carbon double bonds can be introduced into the alkyd resin, allowing the alkyd resin itself to participate in the curing reaction. Therefore, the resulting modified alkyd resin can rapidly cure and crosslink under photoinitiator excitation to form a dense paint film, reducing solvent penetration and improving the solvent resistance of the paint film. Simultaneously, because unsaturated carbon-carbon double bonds are photosensitive, and the consumption of double bonds during the reaction of epoxy silanes and unsaturated dibasic organic acids is relatively small, the modified alkyd resin can rapidly cure into a film under photoinitiator excitation, which is beneficial for improving the curing rate of the modified alkyd resin.

[0014] Therefore, modifying alkyd resins with epoxy-based silanes and unsaturated dibasic organic acids results in modified alkyd resins that possess the dual functions of both epoxy-based silanes and unsaturated dibasic organic acids. UV-curable coatings prepared using these modified alkyd resins as oligomers exhibit rapid curing, high weather resistance, and good solvent resistance after curing. Furthermore, alkyd resins are inexpensive and readily available. Therefore, UV coatings prepared using the modified alkyd resins of this application have lower production costs compared to UV coatings prepared using fluoropolymers.

[0015] Preferably, the alkyd resin has a solid content of 70-80% and a viscosity of 4000-20000 mPa·s.

[0016] By adopting the above technical solution, the alkyd resin has the characteristics of high solid content and low viscosity, and has good compatibility with epoxy silanes, unsaturated dibasic organic acids and their esters, which is beneficial to improving the curing rate, solvent resistance and weather resistance of the modified alkyd resin.

[0017] Preferably, the epoxy silane is one or both of 3-glycidoxypropyltriethoxysilane and 3-glycidoxypropyltrimethoxysilane.

[0018] By adopting the above technical solution, the epoxy silane contains three silicon-oxygen bonds, which increases the number of hydroxyl acrylic resin grafts in the epoxy silane, thereby introducing a large number of silicon-oxygen bonds and carbon-carbon double bonds into the modified alkyd resin, which is beneficial to improving the low-temperature weather resistance and curing rate of the modified alkyd resin.

[0019] Preferably, the unsaturated dicarboxylic organic acid is one or both of itaconic acid and dilinoleic acid.

[0020] By adopting the above technical solution, itaconic acid and dilinoleic acid have active chemical properties, which are beneficial to improving the esterification reaction efficiency of unsaturated dibasic organic acids and epoxy silanes, thereby improving the curing rate, solvent resistance and low temperature weather resistance of modified alkyd resins.

[0021] Preferably, the weight ratio of the alkyd resin, epoxy silane, and unsaturated dibasic organic acid is 1:(0.30-0.39):(0.61-0.70).

[0022] By adopting the above technical solutions, the alkyd resin, epoxy silane, and unsaturated dibasic organic acid are optimized.

[0023] Preferably, the modified alkyd resin has an acid value of 0.4-1 mg KOH / g.

[0024] By adopting the above technical solution, the modified alkyd resin exhibits a high reaction rate, which is beneficial for improving the resin's curing rate. Furthermore, the modified alkyd resin prepared using alkyd resin, epoxy silane, and unsaturated dibasic organic acid also demonstrates good storage stability.

[0025] Secondly, this application provides a method for preparing a modified alkyd resin, employing the following technical solution:

[0026] A method for preparing a modified alkyd resin includes the following preparation steps:

[0027] After stirring and mixing epoxy silane, unsaturated dibasic organic acid and catalyst, alkyd resin is added and stirred to obtain modified alkyd resin.

[0028] By employing the above technical solution, epoxy silanes are hydrolyzed under catalytic conditions to form silanols. Most of the silanols can be esterified with unsaturated dicarboxylic acids. The esterification products are then grafted onto the alkyd resin molecular chain to obtain a modified alkyd resin containing carbon-carbon double bonds and silicon-oxygen bonds, exhibiting characteristics of rapid curing, solvent resistance, and low-temperature weather resistance. Furthermore, the preparation method of the modified alkyd resin in this application is simple, has low preparation cost, and is suitable for industrial production.

[0029] Thirdly, this application provides a UV-curable low-temperature weather-resistant coating, which adopts the following technical solution:

[0030] A UV-curable low-temperature weather-resistant coating comprises the following raw materials in parts by weight:

[0031] 40-70 parts of modified alkyd resin;

[0032] 2-8 parts of photoinitiator;

[0033] 20-30 parts of reactive diluent;

[0034] Additives: 5-8 parts.

[0035] By adopting the above technical solution, the modified alkyd resin exhibits fast curing rate, good solvent resistance and low-temperature weather resistance, and low cost. Therefore, under UV curing conditions, the photoinitiator forms excited ecological molecules and decomposes to form free radicals, enabling the modified alkyd resin, reactive diluent, and monomers to rapidly crosslink and cure into a dense paint with good solvent resistance and low-temperature weather resistance. This helps reduce the cost of weather-resistant UV coatings and is suitable for large-scale promotion.

[0036] Preferably, the photoinitiator is composed of a mixture of coumarin and α-dimethoxy-α-phenylacetophenone.

[0037] Preferably, the photoinitiator is composed of coumarin and α-dimethoxy-α-phenylacetophenone in a weight ratio of 1:(0.8-1.2).

[0038] By adopting the above technical solution, under UV curing conditions, the photoinitiator obtained by compounding coumarin and α-dimethoxy-α-phenylacetophenone in the above weight ratio has a long excited state lifetime, which can promote the formation of a large number of free radicals and is beneficial to improving the curing rate of modified alkyd resin.

[0039] In summary, this application has the following beneficial effects:

[0040] 1. Since this application uses epoxy silane and unsaturated dibasic organic acid to modify alkyd resin, photosensitive unsaturated carbon-carbon double bonds and high bond energy silicon-oxygen bonds are introduced into alkyd resin, the resulting modified alkyd resin has the characteristics of radiation curing, low temperature resistance, solvent resistance and weather resistance.

[0041] 2. By using modified alkyd resin as an oligomer, under the excitation of a photoinitiator, a large number of unsaturated bonds such as carbon-carbon double bonds in the modified alkyd resin are excited and cross-linked, which can be quickly cured into a paint film. The resulting paint film has good low-temperature resistance, solvent resistance and weather resistance; and alkyd resin is inexpensive, which helps to reduce the production cost of UV-cured coatings. Detailed Implementation

[0042] The present application will be further described in detail below with reference to the embodiments.

[0043] Example

[0044] Example 1

[0045] A modified alkyd resin, the raw materials and their weights are shown in the table below:

[0046]

[0047] The preparation method of the above-mentioned modified alkyd resin includes the following preparation steps:

[0048] S1: The alkyd resin is solvent-removed until the solvent content is no more than 5% to obtain a pretreated alkyd resin;

[0049] S2: After mixing epoxy silane, catalyst and ethanol, stir and mix for 0.2 h, then add unsaturated dibasic organic acid and stir and mix at 160 °C for 2 h, finally add pretreated alkyd resin and stir and mix for 1.5 h to obtain modified alkyd resin.

[0050] In the embodiments of this application, the alkyd resin is a short-oil alkyd resin with a viscosity of 4000-9000 mPa.s / 25℃ and 80±1%.

[0051] The epoxy silane is composed of 3-glycidyl etheroxypropyltriethoxysilane and 3-glycidyl etheroxypropyltrimethoxysilane in a weight ratio of 1:1.

[0052] The unsaturated dicarboxylic acid is composed of itaconic acid and dilinoleic acid mixed in a weight ratio of 1:1.

[0053] The catalyst is tetrabutyl titanate.

[0054] Examples 2-6

[0055] A modified alkyd resin, differing from Example 1 in that the raw materials and their weights are shown in the table below:

[0056]

[0057]

[0058] Example 7

[0059] A modified alkyd resin, which differs from Example 1 in that the alkyd resin is a short-oil alkyd resin with a viscosity of 12000-20000 mpa.s / 25℃ and a solid content of 80±1%.

[0060] Example 8

[0061] A modified alkyd resin, differing from Example 1 in that the epoxy silane is 3-glycidoxypropyltriethoxysilane.

[0062] Example 9

[0063] A modified alkyd resin, which differs from Example 1 in that the epoxy silane is 3-glycidoxypropyltrimethoxysilane.

[0064] Example 10

[0065] A modified alkyd resin, differing from Example 1 in that the epoxy silane is 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

[0066] Example 11

[0067] A modified alkyd resin, which differs from Example 1 in that the unsaturated dibasic organic acid is itaconic acid.

[0068] Example 12

[0069] A modified alkyd resin, which differs from Example 1 in that the unsaturated dibasic organic acid is dilinoleic acid.

[0070] Example 13

[0071] A modified alkyd resin, which differs from Example 1 in that the unsaturated dibasic organic acid is adipic acid.

[0072] Comparative Example

[0073] Comparative Example 1

[0074] A modified alkyd resin, which differs from Example 1 in that an equal weight of cyclohexyltrimethoxysilane is used instead of epoxysilane.

[0075] Comparative Example 2

[0076] A modified alkyd resin, which differs from Example 1 in that an equal weight of methacrylic acid is used instead of an unsaturated dibasic organic acid.

[0077] The modified alkyd resins obtained in Examples 1-13 and Comparative Examples 1-2 of this application were tested for acid value and storage stability, and the testing standards are as follows:

[0078] Acid value testing: Refer to HG / T 4763-2014;

[0079] Storage stability test: The modified alkyd resin was stored at room temperature for 6 months, and the presence of precipitation, coarsening, or demulsification was observed.

[0080] The test results are as follows: The modified alkyd resins obtained in Examples 1-13 of this application have an acid value in the range of 0.4-1 mgKOH / g. After being stored at room temperature for 6 months, there was no precipitation, coarsening, or demulsification.

[0081] The modified alkyd resins obtained in Comparative Examples 1-2, with acid values ​​in the range of 2-3 mg KOH / g, showed no precipitation, coarsening, or demulsification after 5 months of storage at room temperature. However, precipitation, coarsening, and demulsification occurred after storage exceeding 5 months. The reason for this may be that the modification of the alkyd resin using a combination of epoxy silane and unsaturated dibasic organic acid results in a more stable modified alkyd resin, thus exhibiting good storage stability.

[0082] Application examples

[0083] Application Example 1

[0084] The raw materials and their corresponding weights for a UV-curable low-temperature weather-resistant coating are shown in the table below:

[0085]

[0086] The preparation method of the above-mentioned UV-curable low-temperature weather-resistant coating is as follows: after mixing the modified alkyd resin, reactive diluent and additives, stir and mix at 1000 r / min for 10 min, then add ethanol, stir and mix at 800 r / min for 10 min, and finally add photoinitiator, stir and mix at 800 r / min for 10 min to obtain the UV-curable low-temperature weather-resistant coating.

[0087] In this application example, the modified alkyd resin was prepared as described in Example 1.

[0088] The photoinitiator is composed of coumarin and α-dimethoxy-α-phenylacetophenone in a weight ratio of 1:1.

[0089] The reactive diluent is hydroxyethyl methacrylate.

[0090] The additives consist of a 1:1 mixture of dispersant and defoamer by weight. The dispersant is brand BYK190 and was purchased from BYK Chemical GmbH, Germany. The defoamer is brand HZX-202 and was purchased from Changzhou Shenyun Chemical Co., Ltd.

[0091] Application Example 2-3

[0092] A UV-curable low-temperature weather-resistant coating differs from Application Example 1 in that the raw materials and their corresponding weights are shown in the table below:

[0093]

[0094]

[0095] Application Example 4-17

[0096] A UV-curable low-temperature weather-resistant coating differs from Application Example 1 in that the modified alkyd resin is different.

[0097] The modified alkyd resins used in the applications and their corresponding examples are shown in the table below:

[0098] Application examples Examples using modified alkyd resins Application Example 1 Example 1 Application Example 2 Example 1 Application Example 3 Example 1 Application Example 4 Example 2 Application Example 5 Example 3 Application Example 6 Example 4 Application Example 7 Example 5 Application Example 8 Example 6 Application Example 9 Example 7 Application Example 10 Example 8 Application Example 11 Example 9 Application Example 12 Example 10 Application Example 13 Example 11 Application Example 14 Example 12 Application Example 15 Example 13 Application Example 16 Comparative Example 1 Application Example 17 Comparative Example 2 Application Example 18 Comparative Example 3

[0099] Application Example 18

[0100] A UV-curable low-temperature weather-resistant coating differs from Application Example 1 in that the photoinitiator is coumarin.

[0101] Application Example 19

[0102] A UV-curable low-temperature weather-resistant coating differs from Application Example 1 in that the photoinitiator is α-dimethoxy-α-phenylacetophenone.

[0103] Performance testing

[0104] For the coatings used in Examples 1-19 of this application, surface drying time, xenon lamp weathering resistance, QUVB weathering resistance, and low-temperature resistance were tested. The testing standards are as follows:

[0105] Surface drying time test: Refer to GB / T1728-1989 Determination of drying time of paint film and putty film;

[0106] Xenon lamp weathering resistance test: Refer to GB / T1865-2009 Paints and Varnishes Artificial climate aging and artificial radiation exposure filtered xenon arc radiation, and test the change level of weathering time and degree of damage.

[0107] QUVB weathering resistance test: Refer to GB / T23987-2009 Artificial weathering of paint and varnish coatings exposed to fluorescent ultraviolet light and water to test the degree of change in weathering time and damage.

[0108] Low temperature resistance test: After the coating specimen is cured, it is placed in a constant temperature and humidity test chamber and placed at -100℃ for X hours. After that, the specimen is taken out and placed at 20-25℃ for 2 hours. Observe whether there are bubbles, whitening, cracking, wrinkling or rusting on the surface of the specimen. The cross-cut test should be ≤2. X hours is the low temperature resistance time of the coating.

[0109] The coatings used in Examples 1-19 of this application were tested for surface drying time, acid resistance, alkali resistance, weather resistance, and low-temperature resistance. The test results are shown in the table below:

[0110]

[0111]

[0112] Analysis of the data in the table above shows that the coatings obtained in Examples 1-3 exhibit a xenon lamp weathering time of 1550-1900 hours, a QUVB weathering time of 810-1000 hours, and a -100℃ low-temperature resistance time of 40-50 hours. This indicates that when modified alkyd resin, photoinitiator, reactive diluent, and additives are mixed in specific weight proportions in the total raw materials for preparing the coatings of this application, the resulting coatings exhibit fast drying rates and good weather resistance and low-temperature resistance. The reason for this may be that the modified alkyd resin contains high-energy silicon-oxygen bonds and silicon-carbon bonds, which improves its low-temperature resistance, solvent resistance, and weather resistance. Therefore, coatings prepared using modified alkyd resin exhibit fast drying rates and good weather resistance and low-temperature resistance.

[0113] Combining Application Examples 1, 4, 5 and 6, 7, 8, and referring to the data in the table above, it can be seen that the xenon lamp weathering time, QUVB weathering time, and -100℃ low-temperature resistance time of the coatings obtained in Application Examples 1, 4, and 5 are all longer than those obtained in Application Examples 6, 7, and 8. This indicates that when the weight ratio of alkyd resin, epoxy silane, and unsaturated dibasic organic acid in the total raw materials for preparing the modified alkyd resin of this application is 1:(0.30-0.39):(0.61-0.70), the final prepared coating has a shorter drying time and better weather resistance and low-temperature resistance.

[0114] Combining Application Examples 1 and 9, and referring to the data in the table above, it can be seen that the xenon lamp weathering time, QUVB weathering time, and -100℃ low-temperature resistance time of the coating obtained in Application Example 1 are all longer than those of the coating obtained in Application Example 9. This indicates that when the solid content of the alkyd resin in the total raw materials for preparing the modified alkyd resin of this application is 70-80% and the viscosity is 4000-20000 mPa·s, the drying time of the final coating can be shortened, and the weather resistance and low-temperature resistance of the coating can be improved.

[0115] Combining Application Examples 1, 10, 11, and 12, and referring to the data in the table above, it can be seen that the xenon lamp weathering time, QUVB weathering time, and -100℃ low-temperature resistance time of the coatings obtained in Application Examples 1, 10, and 11 are all longer than those of the coating obtained in Application Example 12. This indicates that in the total raw materials for preparing the modified alkyd resin of this application, the epoxy silane is one or both of 3-glycidoxypropyltriethoxysilane and 3-glycidoxypropyltrimethoxysilane. In particular, when the epoxy silane is composed of a 1:1 weight mixture of 3-glycidoxypropyltriethoxysilane and 3-glycidoxypropyltrimethoxysilane, the drying efficiency, weather resistance, and low-temperature resistance of the final coating can be improved.

[0116] Combining Application Examples 1, 13, 14, and 15, and referring to the data in the table above, it can be seen that the xenon lamp weathering time, QUVB weathering time, and -100℃ low-temperature resistance time of the coatings obtained in Application Examples 1, 13, and 14 are all longer than those of the coating obtained in Application Example 15. This indicates that in the total raw materials for preparing the modified alkyd resin of this application, the unsaturated dibasic organic acid is one or both of itaconic acid and adipic acid / dilinoleic acid. In particular, when the unsaturated dibasic organic acid is composed of itaconic acid and dilinoleic acid mixed in a weight ratio of 1:1, the drying efficiency, weather resistance, and low-temperature resistance of the final coating can be improved.

[0117] In the preparation of the modified alkyd resin of this application, when the unsaturated dibasic organic acid is composed of itaconic acid and dilinoleic acid in a weight ratio of 1:(1.0-1.4), the performance of the resulting coating is similar to that of Application Example 1. Therefore, this application only uses Application Example 1, in which the unsaturated dibasic organic acid is composed of itaconic acid and dilinoleic acid in a weight ratio of 1:1, as an example for brief explanation, but this does not affect the application of other weight ratios of itaconic acid and dilinoleic acid in this application.

[0118] Combining Application Examples 1 and 16, 17, and referring to the data in the table above, it can be seen that the xenon lamp weathering time, QUVB weathering time, and -100℃ low-temperature resistance time of the coating obtained in Application Example 1 are all longer than those of the coatings obtained in Application Examples 16 and 17. This indicates that, in the total raw materials for preparing the modified alkyd resin of this application, modifying the alkyd resin with epoxy silanes and unsaturated dibasic organic acids can significantly improve the drying efficiency, weather resistance, and low-temperature resistance of the final prepared coating.

[0119] Combining Application Examples 1 and 18, 19, and referring to the data in the table above, it can be seen that the xenon lamp weathering time, QUVB weathering time, and -100℃ low-temperature resistance time of the coating obtained in Application Example 1 are all longer than those of the coatings obtained in Application Examples 18 and 19. This indicates that in the total raw materials for preparing the coating of this application, the photoinitiator is composed of a mixture of coumarin and α-dimethoxy-α-phenylacetophenone. In particular, the photoinitiator is composed of a 1:1 weight ratio of coumarin and α-dimethoxy-α-phenylacetophenone, which can shorten the drying time of the coating and improve its weather resistance and low-temperature resistance.

[0120] In the total raw materials for preparing the coating of this application, when the photoinitiator is composed of coumarin and α-dimethoxy-α-phenylacetophenone in a weight ratio of 1:(0.8-1.2), the performance of the resulting coating is similar to that of Application Example 1. Therefore, this application only uses Application Example 1, in which the photoinitiator is composed of coumarin and α-dimethoxy-α-phenylacetophenone in a weight ratio of 1:1, as an example for brief description, but this does not affect the application of other weight ratios of coumarin and α-dimethoxy-α-phenylacetophenone in this application.

[0121] The coatings used in Examples 1-19 of this application were tested for water resistance and salt water resistance, and the testing standards are as follows:

[0122] Water resistance test: Refer to GB / 1733-1993;

[0123] Salt water resistance test: Refer to GB / T9274-1988.

[0124] The test results are as follows: The coatings of Application Examples 1-17 of this application have a water resistance time of up to 360-480 hours and a salt water (3% sodium chloride) resistance time of up to 288-432 hours. The coatings of Application Examples 18-19 have a water resistance time of up to 200-240 hours and a salt water (3% sodium chloride) resistance time of up to 72-96 hours. Comparing the coatings of Application Examples 1-17 with those of Application Examples 18-19, it can be seen that the coatings of Application Examples 1-17 of this application have higher water resistance and salt water resistance.

[0125] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A modified alkyd resin, characterized in that, The raw materials include the following parts by weight: 20-40 parts of alkyd resin; 5-8 parts of epoxy silane; 10-15 parts of unsaturated dibasic organic acids; Catalyst 0.1-0.3 parts; The alkyd resin has a solid content of 70-80% and a viscosity of 4000-20000 mPa•s; The unsaturated dicarboxylic organic acid is one or both of itaconic acid and dilinoleic acid; The weight ratio of the alkyd resin, epoxy silane, and unsaturated dibasic organic acid is 1:(0.30-0.39):(0.61-0.70).

2. The modified alkyd resin according to claim 1, characterized in that, The epoxy silane is one or both of 3-glycidoxypropyltriethoxysilane and 3-glycidoxypropyltrimethoxysilane.

3. The modified alkyd resin according to claim 1, characterized in that, The modified alkyd resin has an acid value of 0.4-1 mg KOH / g.

4. The method for preparing the modified alkyd resin according to any one of claims 1-3, characterized in that, The preparation steps include the following: After stirring and mixing epoxy silane, unsaturated dibasic organic acid and catalyst, alkyd resin is added and stirred to obtain modified alkyd resin.

5. A UV-curable low-temperature weather-resistant coating, characterized in that, The raw materials include the following parts by weight: 40-70 parts of the modified alkyd resin according to any one of claims 1-3; 2-8 parts of photoinitiator; 20-30 parts of reactive diluent; Additives: 5-8 parts.

6. The UV-curable low-temperature weather-resistant coating according to claim 5, characterized in that, The photoinitiator is composed of a mixture of coumarin and α-dimethoxy-α-phenylacetophenone.

7. The UV-curable low-temperature weather-resistant coating according to claim 6, characterized in that, The photoinitiator is composed of coumarin and α-dimethoxy-α-phenylacetophenone in a weight ratio of 1:(0.8-1.2).

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