A polyurethane acrylate short-cut glass fiber reinforced uv coating and a preparation method thereof

Abstract

This application relates to the field of polymer materials and coatings technology, specifically disclosing a polyurethane acrylate chopped glass fiber reinforced UV coating and its preparation method. A polyurethane acrylate chopped glass fiber reinforced UV coating is made from raw materials comprising the following parts by weight: 30-60 parts polyurethane acrylate, 20-50 parts functional monomers, 2-8 parts photoinitiator, 0.5-3 parts silane coupling agent, 0.5-2 parts ultraviolet absorber, 0.5-2 parts hindered amine light stabilizer, 10-20 parts chopped glass fiber, and 0.1-1 parts organosilicon additive; the organosilicon additive is a reactive organosilicon additive with carbon-carbon double bonds capable of participating in the photocuring reaction. This application significantly improves and enhances the weather resistance, the bonding strength between the chopped glass fiber and the resin, and the resistance to exposure of the chopped glass fiber after aging in the polyurethane acrylate chopped glass fiber reinforced UV coating.

Description

Technical Field

[0001] This application relates to the field of polymer materials and coatings technology, and more specifically, it relates to a polyurethane acrylate chopped glass fiber reinforced UV coating and its preparation method. Background Technology

[0002] UV coatings are widely used in coating substrates such as wood, plastics, metals, and paper due to their advantages such as fast curing speed, environmental friendliness (low VOC emissions), and low energy consumption. To meet the higher requirements for coating hardness, rigidity, and impact resistance in specific applications (such as certain tool handles, industrial parts, and outdoor furniture), short-cut glass fibers (GF) are often added to the coating for reinforcement.

[0003] Conventional UV resins are prone to photoaging under prolonged outdoor ultraviolet radiation, leading to chalking, discoloration, and loss of gloss in the coating. After aging, the resin matrix of chopped glass fiber reinforced systems degrades, exposing the internal glass fibers. This not only affects aesthetics but also poses a safety hazard due to the sharp ends, making them easy to prick. Furthermore, the poor compatibility between glass fibers and organic resins, without effective treatment, results in low interfacial bonding strength, easily becoming stress concentration points and crack propagation channels. This restricts the full effectiveness of fiber reinforcement and affects the long-term durability of the coating. In addition, UV coatings are prone to yellowing, loss of gloss, and cracking under prolonged ultraviolet radiation; poor weather resistance is a key bottleneck limiting their outdoor applications.

[0004] Therefore, providing long-lasting and synergistic weather protection and significantly improving the interfacial bonding between chopped glass fibers and resin in the coating is of urgent market demand and significant technical value for expanding the application of high-performance UV coatings in outdoor and harsh environments. Summary of the Invention

[0005] To address the problems of poor weather resistance, weak bonding between chopped glass fiber and resin, and easy exposure of chopped glass fiber after aging in existing short-cut glass fiber reinforced UV coatings, this application provides a polyurethane acrylate short-cut glass fiber reinforced UV coating and its preparation method.

[0006] In a first aspect, this application provides a polyurethane acrylate chopped glass fiber reinforced UV coating, which adopts the following technical solution: A polyurethane acrylate chopped glass fiber reinforced UV coating is made from raw materials comprising the following parts by weight: 30-60 parts of polyurethane acrylate; 20-50 parts of functional monomer; 2-8 parts of photoinitiator; 0.5-3 parts of silane coupling agent; 0.5-2 parts of ultraviolet absorber; 0.5-2 parts of hindered amine light stabilizer; 10-20 parts chopped glass fiber; 0.1-1 part of organosilicon additive; The organosilicon additive is a reactive organosilicon additive with carbon-carbon double bonds that can participate in the photocuring reaction.

[0007] By adopting the above technical solution, polyurethane acrylate, as the main resin, has higher urethane bond energy in its main chain compared to ordinary acrylic resin, resulting in better chemical resistance and flexibility, providing a more stable "skeleton" for the coating. Synergistically with stabilizers, it significantly delays matrix aging. Functional monomers act as reactive diluents to adjust the system viscosity and curing reaction rate. Photoinitiators absorb ultraviolet light energy, generating free radicals to initiate the polymerization and crosslinking reaction of the resin and monomers. Silane coupling agents are used for surface pretreatment of chopped glass fibers, forming chemical bridges between the chopped glass fibers and the resin matrix, significantly enhancing interfacial bonding strength. Ultraviolet absorbers... It is used to selectively absorb ultraviolet light and convert it into harmless heat energy, reducing the damage of ultraviolet rays to the resin from the source; the hindered amine light stabilizer works synergistically with the ultraviolet absorber to inhibit the aging and degradation chain reaction of the coating by capturing and eliminating free radicals generated during photo-oxidation; the organosilicon additive contains carbon-carbon double bonds, which can participate in the photocuring reaction and become part of the cross-linking network. It not only improves leveling and prevents shrinkage craters, but its organosilicon segments are enriched at the interface, which can further improve the wetting and encapsulation of chopped glass fibers by the resin, reduce stress, and make the bond stronger; chopped glass fibers are used to significantly enhance the hardness, rigidity, tensile strength and impact strength of the coating.

[0008] The combination of the above raw materials forms an integrated "defense-solidification" system. The ultraviolet absorber and hindered amine light stabilizer are active defense systems that target aging factors from an energy and chemical level. The strong interfacial bonding brought by the organosilicon additives and silane coupling agents upgrades the simple physical contact between chopped glass fibers and resin to a strong and tough interface dominated by chemical bonds. This not only significantly improves mechanical properties, but more importantly, it blocks the weak channels for the intrusion of moisture, oxygen, and aging factors. Both are indispensable and work synergistically to greatly delay the time of resin degradation and interfacial failure. As a result, the weather resistance of polyurethane acrylate chopped glass fiber reinforced UV coatings, the bonding strength between chopped glass fibers and resin, and the resistance of chopped glass fibers to exposure after aging are significantly improved.

[0009] Preferably, the chopped glass fibers have a length of 50-200 μm and a diameter of 5-15 μm.

[0010] By adopting the above technical solution, the length range of 50-200μm is far higher than the critical length of common resin-chopped glass fiber systems, which can effectively bear and transfer stress, significantly improving the hardness, rigidity and impact resistance of the coating. If the fiber is too long, it is prone to entanglement and agglomeration in UV coating systems with high viscosity. A diameter of 5-15μm means that its specific surface area (surface area per unit mass) is larger, which is conducive to the action of silane coupling agents and organosilicon additives, thus achieving strong interfacial bonding.

[0011] Preferably, the functional monomer comprises the following components in parts by weight: 10-14 parts of trimethylolpropane triacrylate; 15-17 parts of ethoxylated trimethylolpropane triacrylate; 6-10 parts of isoborneol acrylate; 3-5 parts of 1,6-hexanediol diacrylate.

[0012] By adopting the above technical solutions, trimethylolpropane triacrylate is a high-functionality, high-crosslinking-density core monomer, whose main contribution lies in rapidly constructing a three-dimensional network framework with high crosslinking density; ethoxylated trimethylolpropane triacrylate is a flexible, high-functionality balanced monomer that can significantly reduce the viscosity of the monomer and the volume shrinkage rate during curing, and endow the cured network with better flexibility and impact resistance, and plays a key bridging role between hardness and toughness; isobornyl acrylate is a low-shrinkage, high-adhesion, rigid toughening monomer that can generate a "steric hindrance" effect during polymerization, which can extremely effectively reduce polymerization shrinkage stress; 1,6-hexanediol diacrylate is a low-viscosity, high-dilution-efficiency general-purpose difunctional monomer. It has low viscosity and good dilution ability, which can effectively reduce the initial viscosity of the resin mixture, improve the wettability of chopped glass fibers and the leveling properties of the coating during application. When the above components are combined and used as functional monomers, a "rigid and flexible" network framework can be formed, which is conducive to achieving extremely low shrinkage stress and ultra-strong interfacial bonding. Through the establishment of a synergistic reinforcement system, it can better resist stress cracking and microscopic damage caused by thermal cycling and ultraviolet aging, and achieve a strong interfacial bond between chopped glass fibers and resin, thereby giving polyurethane acrylate chopped glass fiber reinforced UV coatings excellent application quality.

[0013] Preferably, the raw materials also contain 3-5 parts by weight of a reinforcing agent, wherein the reinforcing agent is one or a combination of several of the following: chopped basalt fiber, aramid pulp, calcium sulfate whiskers, and calcium carbonate whiskers.

[0014] By adopting the above technical solution, the use of the above-mentioned reinforcing additives not only strengthens the internal network of the resin and the mechanical interlock between the resin and the chopped glass fibers, but also fills interface defects, making the bond denser. At the same time, by mixing with reinforcing additives of different glass fiber sizes and moduli, a more complex reinforcing network is formed, effectively "binding" the chopped glass fibers that may loosen due to aging, delaying their "pull-out" and exposure process, and improving the overall interface stability. It also forms a more complex stress transmission network in the coating, making the performance more balanced, and thus bringing about a significant enhancement in application stability from the perspectives of microstructure reinforcement, stress dispersion, and defect repair.

[0015] Preferably, the raw materials also contain 2-6 parts by weight of functional additives, which are composed of polyamide wax and nano alumina, and the weight ratio of polyamide wax to nano alumina is (2-4):1.

[0016] By adopting the above technical solution, chopped glass fibers and functional additives are easily settled and separated, while polyamide wax can suspend them uniformly and stably in the system, ensuring that the coating can uniformly, fully, and stably coat each chopped glass fiber, forming a dense and defect-free interface. Nano-alumina can fill the gaps between resin molecular chains and scatter some ultraviolet rays, providing auxiliary protection and helping to disperse the heat generated on the coating surface by light, thus slowing down thermo-oxidative aging. When polyamide wax and nano-alumina are used together as functional additives, they can play an excellent synergistic role, which can not only strengthen the synergistic effect between chopped glass fibers and functional additives, but also significantly improve weather resistance and the bonding force between chopped glass fibers and resin through physical shielding and crack pinning. As a result, chopped glass fibers are less likely to be exposed after aging, which further improves the application quality of polyurethane acrylate chopped glass fiber reinforced UV coatings.

[0017] Preferably, the raw materials also contain 0.5-2 parts by weight of an antioxidant, wherein the antioxidant is composed of a hindered phenolic primary antioxidant and a phosphite secondary antioxidant in a weight ratio of (1.5-2):1.

[0018] By adopting the above technical solutions, the synergistic effect of light, heat and oxygen is the main cause of polymer aging. Antioxidant inhibits the thermal oxidation process inside the resin, significantly delaying the breakage, cross-linking and embrittlement of resin molecular chains. A healthier and tougher resin matrix is ​​the most fundamental guarantee for protecting the glass fiber-resin interface, thereby delaying the degradation of the resin matrix from the root and protecting the interface.

[0019] Secondly, this application provides a method for preparing a polyurethane acrylate chopped glass fiber reinforced UV coating, employing the following technical solution: A method for preparing a polyurethane acrylate chopped glass fiber reinforced UV coating includes the following steps: (1) Prepare raw materials containing polyurethane acrylate, functional monomers, photoinitiators, silane coupling agents, ultraviolet absorbers, hindered amine light stabilizers, chopped glass fibers and organosilicon additives according to the formula ratio; (2) The surface of the chopped glass fiber is pretreated with a silane coupling agent to obtain pretreated chopped glass fiber; (3) Mix polyurethane acrylate and functional monomers evenly, then add photoinitiator, ultraviolet absorber, hindered amine light stabilizer and organosilicon additives and mix evenly. Finally, add pretreated short glass fiber, disperse evenly and degas to obtain polyurethane acrylate short glass fiber reinforced UV coating.

[0020] By employing the above technical solution, a chemical coupling layer is pre-constructed on the surface of chopped glass fibers before they are added to the system. This ensures that the coupling agent molecules can fully and uniformly react with the silanol groups on the surface of the chopped glass fibers to form strong chemical bonds. The pretreated chopped glass fibers transform from "inert fillers" into "active reinforcing materials," laying a solid foundation for strong bonding with the resin. Adding the pretreated chopped glass fibers only after all other raw materials have been thoroughly mixed and homogeneous not only avoids excessively high system viscosity due to premature addition of the chopped glass fibers, which could affect the mixing and dissolution of other liquid components, but also allows the low-viscosity homogeneous liquid to better wet and coat each chopped glass fiber, achieving optimal interfacial bonding. Furthermore, the above preparation method is simple to operate, suitable for large-scale industrial production, and ultimately yields high-quality and stable polyurethane acrylate chopped glass fiber reinforced UV coatings.

[0021] Preferably, in step (2), the specific operation of surface pretreatment of chopped glass fibers with silane coupling agent is to prepare a 1-5 wt% ethanol solution of silane coupling agent, impregnate the chopped glass fibers, and then dry them at 80-120°C to obtain pretreated chopped glass fibers.

[0022] By adopting the above technical solution, the silane coupling agent is prepared into a low-concentration solution, which ensures that it can uniformly coat the surface of each chopped glass fiber in an extremely thin monolayer or oligolayer. This is a prerequisite for forming an effective and strong chemical bond. Subsequently, under heating conditions, dehydration condensation reactions occur between silanols and between silanols and silanols on the surface of the chopped glass fiber, forming strong covalent bonds. This allows the silane coupling agent to be permanently and firmly bonded to the surface of the chopped glass fiber in a chemical manner.

[0023] In summary, this application has the following beneficial effects: 1. This application constructs an active defense system by using ultraviolet absorbers and hindered amine light stabilizers, and builds an integrated "defense-solidification" system through the strong interfacial bonding brought about by organosilicon additives and silane coupling agents. The synergy between them greatly delays the time of resin degradation and interfacial failure, thereby significantly improving the weather resistance, the bonding force between chopped glass fibers and resin, and the resistance of chopped glass fibers to exposure after aging of polyurethane acrylate chopped glass fiber reinforced UV coating. 2. This application utilizes reinforcing agents and functional additives composed of polyamide wax and nano-alumina to synergistically form a more complex stress transfer network in the coating, strengthen the interfacial bond between chopped glass fibers and resin, and provide auxiliary protection. This slows down thermo-oxidative aging, thereby significantly improving weather resistance and the bonding strength between chopped glass fibers and resin. This makes the chopped glass fibers less likely to be exposed after aging, ultimately resulting in a polyurethane acrylate chopped glass fiber reinforced UV coating with better application quality. Detailed Implementation

[0024] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0025] Unless otherwise specified, all raw materials used in the embodiments and comparative examples of this application are commercially available.

[0026] The polyurethane acrylate was purchased from Shanghai Huiyan New Materials Co., Ltd. as HY-7902. The photoinitiator was purchased from photoinitiator 184; The silane coupling agent is type KH-550; The ultraviolet absorber was purchased from Wuhan Xindongyi Chemical Co., Ltd. as UV-531. The hindered amine light stabilizer was purchased from Biaoyue Biotechnology's hindered amine light stabilizer HS-944; The silicone additive was purchased from Tech-25202, a reactive silicone additive. The polyamide wax was purchased from Shenzhen Yoshida Chemical Co., Ltd. as polyamide wax 6900-20X; Nano-alumina was purchased from Weideco Island Gold DK-Al2O3-R30; The hindered phenolic primary antioxidant was purchased from BASF's 1010 antioxidant. Phosphite-based antioxidants were purchased from BASF's antioxidant Irgafos 168. Aramid pulp was purchased from Jiangxi Shuobang New Material Technology Co., Ltd., with a thickness of 1.5mm and a density of 1.45g / cm³. 3 Specific surface area 11 m² 2 / g. Example Example 1

[0027] A polyurethane acrylate chopped glass fiber reinforced UV coating, the raw materials and their corresponding weight parts are shown in Table 1, and it is prepared by the following steps: (1) Prepare raw materials containing polyurethane acrylate, functional monomers, photoinitiators, silane coupling agents, ultraviolet absorbers, hindered amine light stabilizers, chopped glass fibers and organosilicon additives according to the formula ratio; (2) The surface of the chopped glass fiber is pretreated with a silane coupling agent to obtain pretreated chopped glass fiber; (3) Mix polyurethane acrylate and functional monomers evenly, then add photoinitiator, ultraviolet absorber, hindered amine light stabilizer and organosilicon additives and mix evenly. Finally, add pretreated short-cut glass fibers, disperse evenly and then degas at a vacuum of -0.095MPa for 15 minutes to obtain polyurethane acrylate short-cut glass fiber reinforced UV coating.

[0028] Note: In the above operation, the length of the chopped glass fiber is 125 μm and the diameter is 10 μm; the components and corresponding weight parts of the functional monomer are shown in Table 2; the organosilicon additive is a reactive organosilicon additive with carbon-carbon double bonds that can participate in the photocuring reaction. In step (2), the specific operation of surface pretreatment of the chopped glass fiber with silane coupling agent is as follows: the silane coupling agent is prepared into a 3wt% ethanol solution, the chopped glass fiber is impregnated, and then dried at 100℃ to obtain pretreated chopped glass fiber.

[0029] Example 2-3 A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that its raw materials and corresponding weight parts are shown in Table 1.

[0030] Table 1. Raw materials and corresponding weight parts (parts / kg) for Examples 1-3 raw material Example 1 Example 2 Example 3 Polyurethane acrylate 45 30 60 Functional unit 35 20 50 Photoinitiator 5 2 8 Silane coupling agents 1.75 0.5 3 UV absorber 1.25 0.5 2 Hindered amine light stabilizers 1.25 0.5 2 Short-cut glass fiber 15 10 20 Organosilicon additives 0.55 0.1 1 Examples 4-5 A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that the components of the functional monomers and their corresponding weight parts are shown in Table 2.

[0031] Table 2. Components and corresponding weight parts (parts / kg) of functional monomers in Examples 1 and 4-5 Components Example 1 Example 4 Example 5 Trimethylolpropane triacrylate 12 10 14 Ethoxylated trimethylolpropane triacrylate 16 15 17 Isoborneol acrylate 8 6 10 1,6-Hexanediol diacrylate 4 3 5 Example 6

[0032] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that the chopped glass fibers have a length of 50 μm and a diameter of 5 μm. Example 7

[0033] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that the chopped glass fibers have a length of 200 μm and a diameter of 15 μm. Example 8

[0034] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that, in step (2), the specific operation of surface pretreatment of chopped glass fibers with silane coupling agent is as follows: the silane coupling agent is prepared into a 1wt% ethanol solution, the chopped glass fibers are impregnated, and then dried at 80°C to obtain pretreated chopped glass fibers. Example 9

[0035] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that, in step (2), the specific operation of surface pretreatment of chopped glass fibers with silane coupling agent is as follows: the silane coupling agent is prepared into a 5wt% ethanol solution, the chopped glass fibers are impregnated, and then dried at 120°C to obtain pretreated chopped glass fibers. Example 10

[0036] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that it also contains 4 parts by weight of a reinforcing agent, which is aramid pulp, and is added together with the pretreated chopped glass fiber. Example 11

[0037] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 10 in that the reinforcing additive is added in 3 parts by weight. Example 12

[0038] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 10 in that the reinforcing additive is added in 5 parts by weight. Example 13

[0039] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 10 in that it also contains 4 parts by weight of functional additives. The functional additives are composed of polyamide wax and nano alumina in a weight ratio of 3:1, and the functional additives are added together with the pretreated chopped glass fibers. Example 14

[0040] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 13 in that the functional additives are added in 2 parts by weight. Example 15

[0041] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 13 in that the functional additives are added in 6 parts by weight. Example 16

[0042] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 13 in that the functional additives are composed of polyamide wax and nano-alumina in a weight ratio of 2:1. Example 17

[0043] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 13 in that the functional additives are composed of polyamide wax and nano-alumina in a weight ratio of 4:1. Example 18

[0044] A polyurethane acrylate chopped glass fiber reinforced UV coating, which differs from Example 13 in that no reinforcing additives are used in the raw materials. Example 19

[0045] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that it further includes 1.25 parts by weight of an antioxidant additive in the raw materials. This antioxidant additive is composed of a hindered phenolic primary antioxidant and a phosphite secondary antioxidant in a weight ratio of 1.75:1, and is added together with the pretreated chopped glass fibers. Example 20

[0046] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that the amount of antioxidant added is 0.5 parts by weight. Example 21

[0047] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that the antioxidant additive is added in 2 parts by weight. Example 22

[0048] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that the antioxidant additive is composed of a hindered phenolic primary antioxidant and a phosphite secondary antioxidant in a weight ratio of 1.5:1. Example 23

[0049] A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that the antioxidant additive is composed of a hindered phenolic primary antioxidant and a phosphite secondary antioxidant in a weight ratio of 2:1. Comparative Example

[0050] Comparative Example 1 A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that no silane coupling agent is used in the raw materials.

[0051] Comparative Example 2 A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that no silicone additives are used in the raw materials.

[0052] Comparative Example 3 A polyurethane acrylate chopped glass fiber reinforced UV coating differs from Example 1 in that no silane coupling agent or organosilicon additive is used in the raw materials. Performance testing

[0053] Test samples: The polyurethane acrylate chopped glass fiber reinforced UV coatings obtained in Examples 1-23 were selected as test samples 1-23, and the polyurethane acrylate chopped glass fiber reinforced UV coatings obtained in Comparative Examples 1-3 were selected as control samples 1-3.

[0054] Test method: Polyurethane acrylate chopped glass fiber reinforced UV coating was sprayed onto an aluminum plate, and under nitrogen protection, it was tested with 1000 mJ / cm². 2 The samples were cured using UV LED lamps to obtain test samples; The test samples were then subjected to alternating cycles of ultraviolet irradiation (60℃, 4h) and condensation high humidity (50℃, 4h) using UVA-340 lamps, with a test cycle of 500h.

[0055] The following tests were conducted throughout the entire experiment: (1) Measure and calculate the gloss retention rate using a 60° gloss meter. (2) Cut strips from aged samples, test their tensile strength, compare them with unaged samples, and calculate the tensile strength retention rate. (3) Perform surface feel test on the test sample before and after. After performing the above tests on test samples 1-23 and control samples 1-3, the test results are recorded in Table 3. Table 3 Test results of test samples 1-23 and control samples 1-3 sample Gloss retention rate (%) Tensile strength retention rate (%) Surface feel Test sample 1 86.2 88.9 Long-lasting smoothness Test sample 2 85.1 87.8 Long-lasting smoothness Test sample 3 85.8 88.4 Long-lasting smoothness Test sample 4 84.8 87.5 Long-lasting smoothness Test sample 5 84.6 87.2 Long-lasting smoothness Test sample 6 86.0 88.7 Long-lasting smoothness Test sample 7 84.3 87.0 Long-lasting smoothness Test sample 8 85.5 88.1 Long-lasting smoothness Test sample 9 85.3 87.9 Long-lasting smoothness Test sample 10 89.3 92.0 Long-lasting smoothness Test sample 11 88.9 91.6 Long-lasting smoothness Test sample 12 89.1 91.8 Long-lasting smoothness Test sample 13 94.8 97.5 Long-lasting smoothness Test sample 14 94.1 96.9 Long-lasting smoothness Test sample 15 94.5 97.2 Long-lasting smoothness Test sample 16 94.3 97.0 Long-lasting smoothness Test sample 17 94.0 96.7 Long-lasting smoothness Test sample 18 90.1 92.8 Long-lasting smoothness Test sample 19 87.8 90.6 Long-lasting smoothness Test sample 20 87.1 89.8 Long-lasting smoothness Test sample 21 87.5 91.3 Long-lasting smoothness Test sample 22 87.3 91.1 Long-lasting smoothness Test sample 23 87.0 89.7 Long-lasting smoothness Control sample 1 75.9 79.4 It's smooth at first, then becomes slightly astringent. Control sample 2 77.5 80.8 It's smooth at first, then becomes slightly astringent. Control sample 3 71.6 75.3 It feels smooth at first, but then becomes very astringent. Combining Example 1 and Comparative Examples 1-3 with Table 3, it can be seen that in the polyurethane acrylate chopped glass fiber reinforced UV coating, the combination of organosilicon additives and silane coupling agents can significantly improve the gloss retention rate and tensile strength retention rate in the above tests, and maintain a smooth feel after aging treatment. This indicates that the weather resistance of the coating, the bonding force between the chopped glass fiber and the resin, and the resistance of the chopped glass fiber to exposure after aging have been significantly improved. As can be seen from Examples 1 and 10-12 and Table 3, the use of reinforcing additives can further improve gloss retention and tensile strength retention, indicating that they bring about a significant enhancement in application stability from the aspects of microstructure enhancement, stress dispersion, and defect repair. Combining Examples 1 and 13-17 with Table 3, it can be seen that, based on the use of reinforcing additives, the further addition of functional additives composed of polyamide wax and nano-alumina can further improve the gloss retention rate and tensile strength retention rate, indicating that the application quality of polyurethane acrylate chopped glass fiber reinforced UV coatings is further improved. Furthermore, combining Example 18 with Table 3, it can be seen that while adding reinforcing additives or functional additives individually can improve the corresponding effects, the improvement is limited, and the sum of the improvement effects of using them individually is far less than the excellent effect of their combination. Therefore, it is evident that reinforcing additives and functional additives can have an excellent synergistic effect when combined. 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 polyurethane acrylate chopped glass fiber reinforced UV coating, characterized in that, Made from the following ingredients in parts by weight: 30-60 parts of polyurethane acrylate; 20-50 parts of functional monomer; 2-8 parts of photoinitiator; 0.5-3 parts of silane coupling agent; 0.5-2 parts of ultraviolet absorber; 0.5-2 parts of hindered amine light stabilizer; 10-20 parts chopped glass fiber; 0.1-1 part of organosilicon additive; The organosilicon additive is a reactive organosilicon additive with carbon-carbon double bonds that can participate in the photocuring reaction.

2. The polyurethane acrylate chopped glass fiber reinforced UV coating according to claim 1, characterized in that: The chopped glass fibers have a length of 50-200 μm and a diameter of 5-15 μm.

3. The polyurethane acrylate chopped glass fiber reinforced UV coating according to claim 1, characterized in that: The functional monomer comprises the following components in parts by weight: 10-14 parts of trimethylolpropane triacrylate; 15-17 parts of ethoxylated trimethylolpropane triacrylate; 6-10 parts of isoborneol acrylate; 3-5 parts of 1,6-hexanediol diacrylate.

4. The polyurethane acrylate chopped glass fiber reinforced UV coating according to claim 1, characterized in that: The raw materials also contain 3-5 parts by weight of reinforcing agents, which are one or more of the following: chopped basalt fibers, aramid pulp, calcium sulfate whiskers, and calcium carbonate whiskers.

5. The polyurethane acrylate chopped glass fiber reinforced UV coating according to claim 4, characterized in that: The raw materials also contain 2-6 parts by weight of functional additives, which are composed of polyamide wax and nano alumina, and the weight ratio of polyamide wax to nano alumina is (2-4):

1.

6. The polyurethane acrylate chopped glass fiber reinforced UV coating according to claim 1, characterized in that: The raw materials also contain 0.5-2 parts by weight of an antioxidant, which is composed of hindered phenolic primary antioxidant and phosphite auxiliary antioxidant in a weight ratio of (1.5-2):

1.

7. The method for preparing the polyurethane acrylate chopped glass fiber reinforced UV coating according to claim 1, characterized in that: Includes the following steps: (1) Prepare raw materials containing polyurethane acrylate, functional monomers, photoinitiators, silane coupling agents, ultraviolet absorbers, hindered amine light stabilizers, chopped glass fibers and organosilicon additives according to the formula ratio; (2) The surface of the chopped glass fiber is pretreated with a silane coupling agent to obtain pretreated chopped glass fiber; (3) Mix polyurethane acrylate and functional monomers evenly, then add photoinitiator, ultraviolet absorber, hindered amine light stabilizer and organosilicon additives and mix evenly. Finally, add pretreated short glass fiber, disperse evenly and degas to obtain polyurethane acrylate short glass fiber reinforced UV coating.

8. The method for preparing the polyurethane acrylate chopped glass fiber reinforced UV coating according to claim 7, characterized in that: In step (2), the specific operation of surface pretreatment of chopped glass fibers with silane coupling agent is as follows: prepare silane coupling agent into 1-5wt% ethanol solution, impregnate chopped glass fibers, and dry at 80-120℃ to obtain pretreated chopped glass fibers.