Dual-curing UV coating and preparation method thereof

Abstract

The invention belongs to the technical field of dual-curing UV coatings, and discloses a dual-curing UV coating and a preparation method thereof, the coating is composed of a component A and a component B according to a weight ratio of 5-20: 1; the component A is prepared from the following raw materials in parts by weight; the component A is prepared from the following raw materials in parts by weight: 30 to 50 parts of aliphatic polyurethane acrylic resin, 10 to 25 parts of hydroxy acrylic resin, 0.5 to 1 part of an ultraviolet light absorber, 1 to 2 parts of an ultraviolet light initiator, 0.2 to 0.6 part of a light stabilizer, 0.1 to 0.5 part of a drier, 0.2 to 0.6 part of a stain-resistant auxiliary agent and 25 to 30 parts of a composite solvent; the component B is prepared from the following raw materials in parts by weight: 70 to 75 parts of aliphatic polyisocyanate and 20 to 30 parts of solvent. The double-heavy-component design of specific raw materials is adopted, and the obtained coating can have the flexibility of a PU coating and the hardness of a UV coating, has good hardness, weather resistance, adhesive force, chemical resistance and the like, and can be used for outdoor products; the cross-linking efficiency can be effectively improved, and the energy-saving and environment-friendly effects can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of dual-curing UV coating technology, and specifically relates to a dual-curing UV coating and its preparation method. Background Technology

[0002] UV-curable coatings, as a highly efficient and environmentally friendly surface treatment technology, are mainly composed of oligomers, monomers, photoinitiators, and additives. Their curing mechanism involves the decomposition of photoinitiators by specific wavelengths of ultraviolet light, generating active free radicals or ionic groups, which in turn trigger the rapid polymerization and cross-linking of oligomers and monomers, completing the transition from liquid to solid state within seconds to tens of seconds. This technology fully complies with the principles of high efficiency, energy saving, environmental protection, and economy, and has seen rapid development in fields such as optical fiber coatings, adhesives, wood, beverage cans, and food packaging. However, UV-curable coatings still face numerous technical bottlenecks in practical applications, particularly in outdoor applications. Firstly, existing UV-curable coatings lack long-term high-temperature resistance and aging resistance, resulting in limited lifespan in outdoor environments and hindering their widespread adoption. More critically, for complex, irregularly shaped plastic parts, such as those with grooves, deep holes, or irregular structures, single-component UV systems have a fatal flaw: areas where UV light cannot reach or is insufficiently exposed cannot effectively cure and cross-link, leading to a significant decline in coating performance in these shaded areas and impacting overall product quality. Currently, polyurethane (PU) systems are the primary coating technology used in the industry for irregularly shaped plastic parts. PU coatings typically consist of two components: a curing agent containing isocyanate groups (-NCO) and a matrix containing hydroxyl groups (-OH), which react chemically to form a polyurethane polymer. PU coatings offer good flexibility, adhesion, and chemical resistance, making them suitable for coating complex-shaped workpieces. However, PU systems consume excessive energy during curing, often requiring several hours for complete curing, resulting in low production efficiency. Furthermore, PU coatings have inherent limitations in key physical properties such as scratch resistance, abrasion resistance, and hardness; for example, their hardness is significantly lower than that of UV-cured coatings. Additionally, PU coatings have high VOC emissions, indicating a need for improvement in their environmental performance. Therefore, there is an urgent need to develop a new coating technology that can maintain the flexibility and UV aging resistance of PU products while possessing the high crosslinking density and excellent physical properties of UV-cured coatings, thus meeting the demands of modern manufacturing for efficient, environmentally friendly, and high-performance coatings.

[0003] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-curing UV coating and its preparation method, thereby overcoming the defects in the prior art.

[0005] To achieve the above objectives, the present invention provides a dual-curing UV coating, comprising component A and component B in a weight ratio of 5-20:1; component A is composed of the following raw materials in parts by weight: 30-50 parts aliphatic polyurethane acrylic resin, 10-25 parts hydroxyl acrylic resin, 0.5-1 part UV absorber, 1-2 parts UV initiator, 0.2-0.6 parts light stabilizer, 0.1-0.5 parts drying agent, 0.2-0.6 parts stain-resistant additive, and 25-30 parts composite solvent; component B is composed of the following raw materials in parts by weight: 70-75 parts aliphatic polyisocyanate and 20-30 parts solvent.

[0006] Furthermore, preferably, the aliphatic polyurethane acrylic resin is one or a mixture of more than one of the following: Guangzhou Yingxin's 3043, Guangzhou Xinyingyuan's HFC-SG121, Ruisheng Chemical's RU-4128B, and Changxing Chemical's 2380-TF.

[0007] Furthermore, preferably, the hydroxyl acrylic resin is either KN3378H from Kelison or SWU3738 from Kunshan Sanwang.

[0008] Furthermore, as a preferred embodiment, the ultraviolet absorber is Leylon's UV-400.

[0009] Furthermore, preferably, the ultraviolet photoinitiator is either Jiri New Materials 1104 or Jiri New Materials 1108. Further, preferably, the light stabilizer is Rianlon UV-123.

[0010] Furthermore, as a preferred option, the drying agent is American Gas's T-12 drying agent.

[0011] Furthermore, as a preferred option, the stain-resistant additive is L8315 from Tianlong Chemical.

[0012] Furthermore, preferably, the solvent in component B is ethyl acetate or butyl acetate, or a mixture of ethyl acetate and butyl acetate.

[0013] This invention also provides a method for preparing a dual-curing UV coating, comprising the following steps: S1: Weigh aliphatic polyurethane acrylic resin, hydroxyl acrylic resin, ultraviolet light absorber, ultraviolet light initiator, light stabilizer, drying agent, stain-resistant additive, and composite solvent according to the weight parts, and mix the above raw materials evenly to obtain component A. S2: Weigh aliphatic polyisocyanate and solvent according to the weight parts, and mix the above raw materials evenly to obtain component B; S3: Mix component A and component B evenly in proportion to obtain a dual-curing UV coating.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention employs a dual-component design of specific raw materials, resulting in a coating that combines the flexibility of PU coatings with the hardness of UV coatings, exhibiting good hardness, weather resistance, adhesion, and chemical resistance, making it suitable for outdoor products. The crosslinking efficiency of this invention can be effectively improved, thus achieving energy-saving and environmental protection benefits. Detailed Implementation

[0015] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0016] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0017] Example 1: A method for preparing a dual-curing UV coating includes the following steps: S1: Weigh 20 parts of Guangzhou Yingxin's 3043, 10 parts of Guangzhou Xinyingyuan's HFC-SG121, 8 parts of Ruisheng Chemical's RU-4128B, 5 parts of Changxing's 2380-TF, 15 parts of Kelisen's KN3378H, 5 parts of Kunshan Sanwang's SWU3738, 0.4 parts of Lianlong's UV-400, 1 part of Jiuri New Materials' 1104, 1 part of Jiuri New Materials' 1108, 0.2 parts of American Gas T-12, 0.6 parts of Tianlong Chemical's L8315, 0.2 parts of Lianlong's UV-123, 20 parts of ethyl acetate, and 13.6 parts of butyl acetate. Stir the above raw materials at 800 rpm for 20 minutes until they are evenly mixed to obtain component A. S2: Weigh 75 parts of Covestro N3300 and 25 parts of butyl acetate, mix them evenly to obtain component B; S3: Weigh 50 parts of component A and 10 parts of component B, mix them evenly to obtain a dual-curing UV coating.

[0018] Examples 2-3: The difference from Example 1 is the amount of raw materials used. The raw material components of Examples 1-3 are shown in Table 1.

[0019] Comparative Example 1: Unlike Example 1, only the UV system was used. The raw materials of Comparative Example 1 are shown in Table 2.

[0020] Comparative Example 2: Unlike Example 1, only the PU system was used. The raw materials for Comparative Example 2 are shown in Table 3.

[0021] Coatings were prepared using Examples 1-3, Comparative Examples 1 and 2, and their various properties were tested using the following methods: The process for Examples 1-3 and Comparative Example 1 is as follows: Using a pneumatic spray gun with a 1.1mm nozzle and an air pressure of 0.3Mpa, the mixed coating is sprayed onto the workpiece with a film thickness defined as 20-30µm. The baking temperature is 50-55℃ / 5min, the curing energy is 1000-1500mj / cm2, and the strength is 90-150mw / cm2. After curing at 80℃ for 30min, the desired coating is obtained.

[0022] The process of Comparative Example 2 is as follows: using a pneumatic spray gun with a 1.1mm nozzle and an air pressure of 0.3Mpa, the mixed coating is sprayed onto the workpiece, with a film thickness defined as 20-30µm. Then, the coating is baked at 80℃ for 30min to obtain the desired coating.

[0023] The performance test results of the coatings obtained in each embodiment are shown in Table 4.

[0024] Based on the test results of Examples 1-3 above, when the amount of aliphatic polyurethane acrylic resin is too low, the crosslinking density of the coating is affected, which ultimately affects the water boiling performance of the coating. As seen in Comparative Example 1, the xenon lamp test cannot meet the requirements when using a single-component UV system. As seen in Comparative Example 2, the hardness and scratch resistance of the PU system are both lacking. Therefore, it can be seen that when a dual-component design is adopted and the amount of each component reaches a certain proportion, the performance of the coating in all aspects can be effectively improved.

[0025] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A dual-curing UV coating, characterized in that: The product is composed of component A and component B in a weight ratio of 5-20:

1. Component A consists of the following raw materials in parts by weight: 30-50 parts aliphatic polyurethane acrylic resin, 10-25 parts hydroxyl acrylic resin, 0.5-1 part ultraviolet light absorber, 1-2 parts ultraviolet light initiator, 0.2-0.6 parts light stabilizer, 0.1-0.5 parts drying agent, 0.2-0.6 parts stain-resistant additive, and 25-30 parts composite solvent. Component B consists of the following raw materials in parts by weight: 70-75 parts aliphatic polyisocyanate and 20-30 parts solvent.

2. The dual-curing UV coating according to claim 1, characterized in that: The aliphatic polyurethane acrylic resin is one or a mixture of one or more of the following: Guangzhou Yingxin's 3043, Guangzhou Xinyingyuan's HFC-SG121, Ruisheng Chemical's RU-4128B, and Changxing Chemical's 2380-TF.

3. The dual-curing UV coating according to claim 1, characterized in that: The hydroxyl acrylic resin used is either KN3378H from Kelison or SWU3738 from Kunshan Sanwang.

4. The dual-curing UV coating according to claim 1, characterized in that: The ultraviolet light absorber used is Rion's UV-400.

5. The dual-curing UV coating according to claim 1, characterized in that: The ultraviolet photoinitiator used is either Jiuri New Material 1104 or Jiuri New Material 1108.

6. The dual-curing UV coating according to claim 1, characterized in that: The light stabilizer used is Rionon's UV-123.

7. The dual-curing UV coating according to claim 1, characterized in that: The drying agent used is T-12 drying agent from American Gases.

8. The dual-curing UV coating according to claim 1, characterized in that: The stain-resistant additive used is L8315 from Tianlong Chemical.

9. The dual-curing UV coating according to claim 1, characterized in that: The solvent in component B is ethyl acetate, butyl acetate, or a mixture of ethyl acetate and butyl acetate.

10. A method for preparing the dual-curing UV coating according to any one of claims 1-9, characterized in that: Includes the following steps: S1: Weigh aliphatic polyurethane acrylic resin, hydroxyl acrylic resin, ultraviolet light absorber, ultraviolet light initiator, light stabilizer, drying agent, stain-resistant additive, and composite solvent according to the weight parts, and mix the above raw materials evenly to obtain component A. S2: Weigh aliphatic polyisocyanate and solvent according to the weight parts, and mix the above raw materials evenly to obtain component B; S3: Mix component A and component B evenly in proportion to obtain a dual-curing UV coating.

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