Light-triggered self-repairing glass steel tile and preparation and repair method thereof

Abstract

This invention discloses a light-triggered self-healing fiberglass roofing sheet and its preparation and repair methods, belonging to the field of polymer composite materials technology. The fiberglass roofing sheet consists of a resin matrix and a surface layer. The surface layer contains a uniformly dispersed photoresponsive self-healing system composed of polymerizable repair monomers, cationic photoinitiators, and photosensitizers, along with a compounded ultraviolet absorber to enhance weather resistance. The preparation process employs a combination of double-layer co-extrusion and continuous pultrusion processes, enabling integrated molding of the surface functional layer and the resin structural layer, resulting in high production efficiency and stable molding quality. This invention only deploys the photoresponsive self-healing system on the surface layer, eliminating the need to add repair components to the entire resin matrix. While ensuring the overall structural strength of the fiberglass roofing sheet, this significantly reduces production costs. The product exhibits excellent weather resistance and stable repair effects, making it suitable for the industrial-scale production and rapid on-site repair needs of outdoor building materials.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, and more specifically, it relates to a light-triggered self-healing fiberglass tile and its preparation and repair methods. Background Technology

[0002] Fiberglass roofing sheets, as a new type of high-polymer composite material roofing material, are widely used in various outdoor applications such as building roofs, greenhouses, chemical plants, and warehouses due to their outstanding advantages, including light weight, high mechanical strength, excellent corrosion resistance, good insulation, and convenient construction. However, during long-term outdoor service, fiberglass roofing sheets are susceptible to the combined effects of various factors, including prolonged ultraviolet radiation, alternating day and night temperature changes, wind and sand impact, and external friction and collision. This can easily lead to micro-cracks on their surface. If these micro-cracks are not repaired in time, they will gradually extend into the interior of the roofing sheet, resulting in a decrease in the overall mechanical strength and a deterioration in sealing performance. Ultimately, this can cause safety hazards such as leaks and damage, severely shortening the sheet's service life.

[0003] Currently, the main method for repairing damage to the surface of fiberglass roofing sheets relies on manual application of resin repair agents. This method has problems such as cumbersome operation, low repair efficiency, and high labor costs. Furthermore, it is difficult to accurately repair small micro-cracks, and the bonding between the repair agent and the fiberglass roofing sheet substrate is poor after repair, which cannot achieve long-term repair effects and cannot meet the repair needs of large outdoor building materials.

[0004] Most existing self-healing materials use a thermal repair mechanism, which requires high temperatures to trigger the repair reaction. This method is not suitable for on-site repair of large outdoor fiberglass roofing sheets. A few light-based repair systems have drawbacks such as low repair efficiency, the need for complex ultraviolet shielding design, and insufficient weather resistance, making them unsuitable for the industrial-scale production and long-term outdoor use of fiberglass roofing sheets. Summary of the Invention

[0005] This invention aims to solve the technical problems of existing fiberglass roofing sheets being prone to cracking during long-term outdoor use, difficulty in accurately repairing minor damage, and low efficiency and high cost of existing repair methods. It provides a light-triggered self-healing fiberglass roofing sheet and its preparation and repair methods.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A light-triggered self-healing fiberglass roofing sheet is disclosed. The fiberglass roofing sheet comprises a resin matrix and a surface layer. The surface layer tightly coats the surface of the resin matrix, and a light-responsive self-healing system is disposed only in the surface layer. The light-responsive self-healing system is a synergistic system of polymerizable repair monomers, cationic photoinitiators, and photosensitizers. The three components are uniformly dispersed in the surface layer and work synergistically to achieve the light-triggered self-healing function, which can ensure a good repair effect without affecting the overall mechanical properties of the resin matrix.

[0008] Furthermore, the polymerizable repair monomer is a mixture of vinyl ether monomers and epoxy monomers, wherein the weight ratio of vinyl ether monomers to epoxy monomers is 1.5:1 to 3:1; preferably, the vinyl ether monomer is triethylene glycol divinyl ether and the epoxy monomer is bisphenol A diglycidyl ether. The two monomers have excellent compatibility and can synergistically improve the polymerization reaction rate and repair effect, effectively ensuring that the mechanical properties of the surface layer and the resin matrix match after repair, and avoiding the problem of separation between the repair area and the matrix.

[0009] Furthermore, the cationic photoinitiator is diphenyliodonium hexafluorophosphate, and its addition amount is 0.5%-2% of the weight of the surface layer. This initiator can rapidly decompose under ultraviolet irradiation to produce protic acid, thereby initiating the cationic polymerization reaction of polymerizable repair monomers, achieving effective filling of cracks and rapid recovery of mechanical strength.

[0010] Furthermore, the surface layer also contains a photosensitizer and an ultraviolet absorber; the photosensitizer is 2-isopropylthioxanthone, added at 0.1%–0.3% of the surface layer weight; the ultraviolet absorber is UV-531, added at 0.3%–0.5% of the surface layer weight. UV-531 effectively absorbs outdoor ultraviolet radiation, delaying the aging process of the resin matrix and surface layer, protecting the activity of the photoresponsive self-healing system, and significantly improving the long-term weather resistance of the product.

[0011] Furthermore, the thickness of the surface layer is 0.2-0.5mm. This thickness design ensures the effective content of the photoresponsive self-healing system, guaranteeing full repair after damage, while avoiding increased production costs and product weight due to an excessively thick surface layer, thus balancing practicality and economy. During repair, the ultraviolet light wavelength irradiating the damaged area is 365nm, the light intensity is ≥50mW / cm², and the irradiation time is 60-120 seconds. After repair, the bending strength recovery rate of the fiberglass tile is ≥85%, which fully meets the mechanical performance requirements for outdoor use.

[0012] In this application, 2-isopropylthioxanthone serves as a photosensitizer, forming a highly efficient synergistic effect with the cationic photoinitiator (diphenyliodonium hexafluorophosphate). The specific mechanism is as follows: Although diphenyliodonium hexafluorophosphate can directly absorb ultraviolet light energy and decompose to produce protonated acids, thereby initiating the cationic polymerization reaction of polymerizable repair monomers, this initiator has limited absorption efficiency for 365nm ultraviolet light, resulting in a slow polymerization rate and insufficient repair, making it difficult to achieve rapid and efficient repair. In contrast, 2-isopropylthioxanthone has a strong absorption capacity for 365nm ultraviolet light, rapidly absorbing ultraviolet light energy and transferring it to the cationic photoinitiator, promoting its rapid decomposition to produce sufficient protonated acids. This effectively solves the problem of low absorption efficiency of a single cationic initiator at a specific wavelength, achieving deep curing and rapid repair of polymerizable repair monomers. Therefore, the photosensitizer is an indispensable component of the photoresponsive self-healing system of this invention, and it needs to work synergistically with the cationic photoinitiator to achieve a highly efficient phototriggered repair effect.

[0013] A method for preparing light-triggered self-healing fiberglass roofing sheets employs a continuous pultrusion molding process combined with a two-layer co-extrusion process, resulting in high production efficiency and stable molding quality. The specific processing steps are as follows:

[0014] S1. Material Preparation: Unsaturated polyester resin, polymerizable repair monomer, cationic photoinitiator and photosensitizer are mixed in proportion and stirred until uniformly dispersed. Then, curing agent (methyl ethyl ketone peroxide) and accelerator (cobalt naphthic acid) are added and stirred until the system is homogeneous to obtain the surface layer material. At the same time, resin matrix material is prepared. The resin matrix material is an unsaturated polyester resin system that does not contain polymerizable repair monomer, cationic photoinitiator and photosensitizer, and only contains unsaturated polyester resin, curing agent and accelerator to ensure the mechanical strength of the resin matrix.

[0015] S2. Co-extrusion treatment: Using the SJZ-65 / 132 type double-layer co-extrusion equipment, the resin matrix material and the surface layer material are extruded simultaneously. The extrusion speed is strictly controlled to match the subsequent traction speed, so that the surface layer material is uniformly and tightly coated on the surface of the resin matrix material, forming a double-layer composite material with regular structure and strong interfacial bonding, effectively avoiding defects such as delamination and uneven coating.

[0016] S3. Curing and Molding: The double-layer composite material obtained in S2 is fed into a heated mold, and the mold temperature is controlled at 120-150℃ for constant temperature curing and molding. This ensures that the resin matrix and the surface layer are cured synchronously to form a strong integrated structure, while preventing the photo-responsive self-healing system in the surface layer from undergoing premature polymerization reaction.

[0017] S4. Traction molding: After the material in the mold has completely solidified, the molded fiberglass tile is pulled out of the mold at a traction speed of 0.5-1.5m / min. After natural cooling to room temperature, the light-triggered self-healing fiberglass tile is obtained, ensuring the dimensional accuracy and mechanical properties of the finished product.

[0018] A light-triggered self-healing method for repairing surface damage of fiberglass roofing sheets is disclosed. This method is convenient, requires no complex equipment, and enables rapid on-site repair. The specific operation is as follows: A 365nm ultraviolet LED lamp is used to irradiate the damaged area of ​​the fiberglass roofing sheet surface with a light intensity of 50-100mW / cm² for 60-120 seconds. After irradiation, the fiberglass roofing sheet is placed at room temperature for 30 minutes to allow the polymerizable repair monomers to fully complete the polymerization reaction, effectively filling the cracks and restoring the mechanical and sealing properties of the sheet surface, thus completing the surface damage repair.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] By setting a photoresponsive self-healing system composed of polymerizable repair monomers, cationic photoinitiators, and photosensitizers in the surface layer of fiberglass roofing sheets, the overall mechanical properties of the resin matrix are not affected, the interference of repair monomers on the matrix structure is avoided, and the repair monomers are concentrated in the surface area prone to damage, reducing the amount used and thus controlling material costs. At the same time, the photoresponsive self-healing system remains inert under normal use conditions and is activated only under ultraviolet irradiation, realizing the artificial controllability of the repair function. Attached Figure Description

[0021] Figure 1 : Preparation process flow diagram;

[0022] Figure 2 : Repair process diagram. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can understand and implement it. For example... Figures 1-2 As shown, in the following examples and comparative examples, all experiments and tests were strictly performed in accordance with the national standards GB / T1447-2005 "Test Method for Tensile Properties of Fiber Reinforced Plastics" and GB / T 1449-2005 "Test Method for Bending Properties of Fiber Reinforced Plastics". Damage simulation was performed using the blade scratch method, with specific parameters of scratch length 50 mm, width 0.2 mm, and depth 0.15 mm, simulating minor damage during actual outdoor use. Aging tests were performed using an ultraviolet aging test chamber, with test conditions of irradiation time 500 h, temperature 40 ℃, ultraviolet wavelength 365 nm, and light intensity 80 mW / cm², simulating a long-term outdoor ultraviolet irradiation environment.

[0024] Example 1

[0025] A light-triggered self-healing fiberglass tile includes a resin matrix and a surface layer with a surface layer thickness of 0.35 mm. The resin matrix is ​​made of 191# unsaturated polyester resin, and the surface layer contains polymerizable repair monomers, cationic photoinitiators, photosensitizers, and ultraviolet absorbers uniformly dispersed in it.

[0026] The polymerizable repair monomer is a mixture of triethylene glycol divinyl ether and bisphenol A diglycidyl ether in a weight ratio of 2:1; the cationic photoinitiator is diphenyliodonium hexafluorophosphate, added at 1.5% of the surface layer weight; the photosensitizer is 2-isopropylthioxanthone, added at 0.2% of the surface layer weight; and the ultraviolet absorber is UV-531, added at 0.4% of the surface layer weight.

[0027] The specific steps of the above-mentioned method for preparing light-triggered self-healing fiberglass roofing sheets are as follows:

[0028] S1. Material Preparation: 191# unsaturated polyester resin, triethylene glycol divinyl ether, bisphenol A diglycidyl ether, and diphenyliodonium hexafluorophosphate are mixed in proportion and stirred for 20 minutes until uniformly dispersed. Then, a curing agent (methyl ethyl ketone peroxide) and an accelerator (cobalt naphthic acid) are added, and stirring is continued for 8 minutes until the system is homogeneous to obtain the surface layer material. At the same time, a resin matrix material is prepared. The resin matrix material is a 191# unsaturated polyester resin system that does not contain the above-mentioned repair monomers, photoinitiators, photosensitizers, and ultraviolet absorbers, and only contains 191# unsaturated polyester resin, curing agent, and accelerator. Among them, the curing agent and accelerator are conventional auxiliary materials in the preparation process of unsaturated polyester resin. Their selection and addition methods are all standard industry practices. Those skilled in the art can flexibly select suitable conventional systems according to actual curing needs.

[0029] S2. Co-extrusion treatment: Using the SJZ-65 / 132 type double-layer co-extrusion equipment, the resin matrix material and the surface layer material are extruded simultaneously. The extrusion speed is controlled to match the subsequent traction speed, so that the surface layer material is uniformly and tightly coated on the surface of the resin matrix material to form a double-layer composite material.

[0030] S3. Curing and Molding: The double-layer composite material is fed into a heated mold, the mold temperature is controlled at 135℃, and it is cured at a constant temperature for 15 minutes to ensure that the resin matrix and the surface layer are cured synchronously to form a strong integrated structure.

[0031] S4. Traction molding: After the material has completely solidified, the molded fiberglass tile is pulled out of the mold at a traction speed of 1.0 m / min and allowed to cool naturally to room temperature to obtain the finished product of light-triggered self-healing fiberglass tile.

[0032] The repair method for the above-mentioned damage to the surface of fiberglass roofing sheets is as follows: artificial scratches are created using a blade scratching method (scratch length 50mm, width 0.2mm, depth 0.15mm); a 365nm ultraviolet LED lamp is used to irradiate the damaged area of ​​the surface layer with a light intensity of 60mW / cm² for 90 seconds; after irradiation, the area is left at room temperature for 30 minutes to complete the repair.

[0033] Test results: The flexural strength recovery rate was 88%; after 500 hours of artificial accelerated aging, the flexural strength recovery rate was still 86%, and there was no obvious yellowing or cracking on the surface, achieving good repair effect and long-term weather resistance; this slight attenuation is mainly due to the effective protection of the UV-531 photo-responsive self-healing system, which can inhibit the photodegradation of the repair components. At the same time, the synergistic effect of epoxy thermoplastic prepolymer and repair monomer can alleviate material aging fatigue and ensure the long-term stability of repair performance.

[0034] Example 2

[0035] A light-triggered self-healing fiberglass tile includes a resin matrix and a surface layer with a surface layer thickness of 0.2 mm. The resin matrix is ​​made of 191# unsaturated polyester resin, and the surface layer contains polymerizable repair monomers, cationic photoinitiators, photosensitizers, and ultraviolet absorbers.

[0036] The polymerizable repair monomer is a mixture of triethylene glycol divinyl ether and bisphenol A diglycidyl ether, with a weight ratio of 1.5:1; the cationic photoinitiator is diphenyliodonium hexafluorophosphate, added at 0.5% of the surface layer weight; the photosensitizer is 2-isopropylthioxanthone, added at 0.1% of the surface layer weight; and the ultraviolet absorber is UV-531, added at 0.3% of the surface layer weight.

[0037] The specific steps of the above-mentioned method for preparing light-triggered self-healing fiberglass roofing sheets are as follows:

[0038] S1. Material Preparation: 191# unsaturated polyester resin, triethylene glycol divinyl ether, bisphenol A diglycidyl ether, and diphenyliodonium hexafluorophosphate are mixed in proportion and stirred for 15 minutes until uniformly dispersed. Then, a curing agent (methyl ethyl ketone peroxide) and an accelerator (cobalt naphthic acid) are added, and stirring is continued for 5 minutes until the system is homogeneous to obtain the surface layer material. At the same time, a resin matrix material is prepared. The resin matrix material is a 191# unsaturated polyester resin system that does not contain the above-mentioned repair monomers, photoinitiators, photosensitizers, and ultraviolet absorbers. The curing agent and accelerator used here are conventional combinations for curing unsaturated polyester resins and are common knowledge in the field. Their function is only to ensure the resin is cured and formed, and does not affect the realization of the photo-triggered self-healing function of this invention.

[0039] S2. Co-extrusion treatment: Using the SJZ-65 / 132 type double-layer co-extrusion equipment, the resin matrix material and the surface layer material are extruded simultaneously. The extrusion speed is controlled to match the subsequent traction speed, so that the surface layer material is uniformly coated on the surface of the resin matrix material to form a double-layer composite material.

[0040] S3. Curing and molding: The double-layer composite material is fed into a heated mold, the mold temperature is controlled at 120℃, and it is cured at a constant temperature for 20 minutes.

[0041] S4. Traction molding: After the material has completely solidified, the molded fiberglass tile is pulled out of the mold at a traction speed of 0.5 m / min and allowed to cool naturally to room temperature to obtain the finished product of light-triggered self-healing fiberglass tile.

[0042] Repair test: Artificial scratches were created using a blade scratching method. A 365nm ultraviolet LED lamp was used to irradiate the damaged area with a light intensity of 50mW / cm² for 60 seconds. After irradiation, the area was left at room temperature for 30 minutes.

[0043] Test results: The bending strength recovery rate was 85.2%, which can achieve a good repair effect; after 500 hours of artificial accelerated aging, the bending strength recovery rate was 83.5%, which showed good weather resistance and fully met the requirements for outdoor use.

[0044] Example 3

[0045] A light-triggered self-healing fiberglass tile includes a resin matrix and a surface layer with a surface layer thickness of 0.5 mm. The resin matrix is ​​made of 191# unsaturated polyester resin, and the surface layer contains polymerizable repair monomers, cationic photoinitiators, photosensitizers, and ultraviolet absorbers.

[0046] The polymerizable repair monomer is a mixture of triethylene glycol divinyl ether and bisphenol A diglycidyl ether in a weight ratio of 3:1; the cationic photoinitiator is diphenyliodonium hexafluorophosphate, added at 2% of the surface layer weight; the photosensitizer is 2-isopropylthioxanthone, added at 0.3% of the surface layer weight; and the ultraviolet absorber is UV-531, added at 0.5% of the surface layer weight.

[0047] The specific steps of the above-mentioned method for preparing light-triggered self-healing fiberglass roofing sheets are as follows:

[0048] S1. Material Preparation: 191# unsaturated polyester resin, triethylene glycol divinyl ether, bisphenol A diglycidyl ether, and diphenyliodonium hexafluorophosphate are mixed in proportion and stirred for 25 minutes until uniformly dispersed. Then, curing agent (methyl ethyl ketone peroxide) and accelerator (cobalt naphthic acid) are added, and stirring is continued for 10 minutes until the system is homogeneous to obtain the surface layer material. At the same time, the resin matrix material is prepared. The resin matrix material is a 191# unsaturated polyester resin system that does not contain the above-mentioned repair monomers, photoinitiators, photosensitizers, and ultraviolet absorbers. The curing agent and accelerator are conventional auxiliary materials for curing unsaturated polyester resin, and their use is a conventional technical means that can be mastered by those skilled in the art without creative labor.

[0049] S2. Co-extrusion treatment: Using the SJZ-65 / 132 type double-layer co-extrusion equipment, the resin matrix material and the surface layer material are extruded simultaneously. The extrusion speed is controlled to match the subsequent traction speed, so that the surface layer material is uniformly coated on the surface of the resin matrix material to form a double-layer composite material.

[0050] S3. Curing and molding: The double-layer composite material is fed into a heated mold, the mold temperature is controlled at 150℃, and it is cured at a constant temperature for 10 minutes.

[0051] S4. Traction molding: After the material has completely solidified, the molded fiberglass tile is pulled out of the mold at a traction speed of 1.5m / min and allowed to cool naturally to room temperature to obtain the finished product of light-triggered self-healing fiberglass tile.

[0052] Repair test: Artificial scratches were created using a blade scratching method. The damaged area was then irradiated with a 365nm ultraviolet LED lamp at a light intensity of 100mW / cm² for 120 seconds. After irradiation, the area was left at room temperature for 30 minutes.

[0053] Test results: The flexural strength recovery rate was 86.5%, and no over-curing or brittleness was observed; after 500 hours of artificial accelerated aging, the flexural strength recovery rate was 84.8%, indicating good weather resistance and stable and reliable mechanical properties.

[0054] Example 4

[0055] A light-triggered self-healing fiberglass tile includes a resin matrix and a surface layer with a surface layer thickness of 0.35 mm. The resin matrix is ​​made of 191# unsaturated polyester resin, and the surface layer contains polymerizable repair monomers, cationic photoinitiators, photosensitizers, and ultraviolet absorbers.

[0056] The polymerizable repair monomer is a mixture of triethylene glycol divinyl ether and bisphenol A diglycidyl ether, with a weight ratio of 1.5:1; the cationic photoinitiator is diphenyliodonium hexafluorophosphate, added at 1.0% of the surface layer weight; the photosensitizer is 2-isopropylthioxanthone, added at 0.15% of the surface layer weight; and the ultraviolet absorber is UV-531, added at 0.4% of the surface layer weight.

[0057] The preparation method is basically the same as in Example 1, except that the mold temperature is adjusted to 130℃ and the traction speed is 0.8m / min; the repair test uses a 365nm ultraviolet LED lamp to irradiate the damaged area with a light intensity of 75mW / cm² for 80 seconds.

[0058] Test results: The bending strength recovery rate was 87.3%, and the recovery rate was 85.1% after 500 hours of artificial accelerated aging. It can still achieve good repair effect and weather resistance, which fully proves the stability of the technical solution of the present invention.

[0059] Example 5

[0060] A light-triggered self-healing fiberglass tile includes a resin matrix and a surface layer with a surface layer thickness of 0.35 mm. The resin matrix is ​​made of 191# unsaturated polyester resin, and the surface layer contains polymerizable repair monomers, cationic photoinitiators, photosensitizers, and ultraviolet absorbers.

[0061] The polymerizable repair monomer is a mixture of triethylene glycol divinyl ether and bisphenol A diglycidyl ether in a weight ratio of 3:1; the cationic photoinitiator is diphenyliodonium hexafluorophosphate, added at 1.8% of the surface layer weight; the photosensitizer is 2-isopropylthioxanthone, added at 0.25% of the surface layer weight; and the ultraviolet absorber is UV-531, added at 0.4% of the surface layer weight.

[0062] The preparation method is basically the same as in Example 1, except that the mold temperature is adjusted to 140℃ and the traction speed is 1.2m / min; the repair test uses a 365nm ultraviolet LED lamp to irradiate the damaged area with a light intensity of 90mW / cm² for 100 seconds.

[0063] Test results: The bending strength recovery rate was 87.8%, and the recovery rate was 85.5% after 500 hours of artificial accelerated aging. The repair effect was stable, further verifying the feasibility and stability of the technical solution of the present invention.

[0064] Comparative Example 1

[0065] A fiberglass roofing sheet, with the same formula, preparation method and repair test as Example 1, except that the photosensitizer (2-isopropylthioxanthone) is not added, and all other conditions are exactly the same.

[0066] Test results: The bending strength recovery rate was only 45%, and the recovery rate was 42% after 500 hours of artificial accelerated aging.

[0067] Analysis: The photosensitizer and the cationic photoinitiator have a significant synergistic effect. The photosensitizer can effectively improve the absorption efficiency of the cationic photoinitiator for 365nm ultraviolet light, promote its rapid decomposition to produce protic acid, and then initiate the polymerization reaction of polymerizable repair monomers. This is crucial for the initiation of the cationic system under the conditions of this application. Without the photosensitizer, the light absorption efficiency of the single cationic photoinitiator is low, and the polymerization reaction is difficult to proceed fully, resulting in a significant decrease in the repair effect. This fully demonstrates that the photosensitizer is an essential component of the photoresponsive self-repairing system of this invention.

[0068] Comparative Example 2

[0069] A fiberglass roofing sheet, with the same formula, preparation method and repair test as Example 1, except that the ultraviolet absorber (UV-531) is not added, and all other conditions are exactly the same.

[0070] Test results: The bending strength recovery rate of the fresh sample was 88%, consistent with Example 1. However, after 500 hours of artificial accelerated aging, the bending strength recovery rate dropped to 60%, and obvious yellowing and microcracks appeared on the surface.

[0071] Analysis: UV-531 can effectively absorb outdoor ultraviolet light, delay the photo-oxidative aging of the resin matrix and surface layer, and protect the activity of the photo-responsive self-healing system (polymerizable repair monomers, cationic photoinitiators, and photosensitizers), which is crucial for maintaining the long-term repair performance of the product. Without UV-531, the photo-responsive self-healing system will degrade and deactivate under long-term ultraviolet irradiation, leading to a decrease in the product's weather resistance and a significant decline in repair performance over aging time, proving that UV-531 is indispensable for improving the long-term weather resistance of the product.

[0072] Comparative Example 3

[0073] A fiberglass roofing sheet with the same formulation as Example 1, but using only a single-layer structure, with polymerizable repair monomers, cationic photoinitiators, photosensitizers and ultraviolet absorbers directly added to the entire resin matrix instead of just placed in the surface layer; the preparation method uses a single-layer pultrusion process instead of a double-layer co-extrusion and continuous pultrusion co-molding process, and all other conditions are exactly the same.

[0074] Test results: The bending strength recovery rate was 87%, and the recovery rate was 84% ​​after 500 hours of artificial accelerated aging. The repair effect was similar to that of Example 1, but the overall tensile strength of the tile decreased by 12% compared to Example 1, the amount of repair material used increased by 30%, and the production cost increased significantly.

[0075] Analysis: A comparison of Example 1 and Comparative Example 3 shows that the "resin matrix + surface layer" two-layer structure of the present invention has significant advantages. By setting the photoresponsive self-healing system only in the surface layer, the repair effect can be guaranteed while avoiding interference from low molecular weight repair monomers on the cross-linking structure of the resin matrix, thus preventing a decrease in the overall mechanical strength of the tile. Simultaneously, since the repair material is only used in the surface layer, the amount used is significantly reduced, effectively lowering production costs and making it more suitable for large-scale industrial applications.

[0076] The experimental data from the above embodiments and comparative examples show that the light-triggered self-healing fiberglass tile of the present invention has significantly better repair effect, mechanical properties and anti-aging properties than the prior art, fully demonstrating the technical advantages of the present invention.

[0077] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A light-triggered self-healing fiberglass roofing sheet, characterized in that, It includes a resin matrix and a surface layer, wherein the surface layer is tightly coated on the surface of the resin matrix and a photoresponsive self-healing system is disposed in the surface layer. The photoresponsive self-healing system is composed of a polymerizable repair monomer, a cationic photoinitiator and a photosensitizer, which are uniformly dispersed in the surface layer.

2. The light-triggered self-healing fiberglass roofing sheet according to claim 1, characterized in that, The polymerizable repair monomer is a mixture of vinyl ether monomers and epoxy monomers, wherein the weight ratio of vinyl ether monomers to epoxy monomers is 1.5:1 to 3:

1.

3. The light-triggered self-healing fiberglass roofing sheet according to claim 2, characterized in that, The vinyl ether monomer is triethylene glycol divinyl ether, and the epoxy monomer is bisphenol A diglycidyl ether.

4. The light-triggered self-healing fiberglass roofing sheet according to claim 1, characterized in that, The cationic photoinitiator is diphenyliodonium hexafluorophosphate, and its addition amount is 0.5%-2% of the weight of the surface layer.

5. The light-triggered self-healing fiberglass roofing sheet according to claim 1, characterized in that, The photosensitizer is 2-isopropylthioxanthone, and the amount added is 0.1%-0.3% of the weight of the surface layer; the surface layer also contains a UV absorber, which is UV-531, and the amount added is 0.3%-0.5% of the weight of the surface layer.

6. The light-triggered self-healing fiberglass roofing sheet according to claim 1, characterized in that, The thickness of the surface layer is 0.2 to 0.5 mm; during repair, the ultraviolet wavelength of the irradiated area is 365 nm, the light intensity is ≥50 mW / cm², and the irradiation time is 60 to 120 seconds.

7. The light-triggered self-healing fiberglass roofing sheet according to claim 6, characterized in that, The bending strength recovery rate of the repaired fiberglass roofing sheet is ≥85%.

8. A method for preparing a light-triggered self-healing fiberglass tile, characterized in that, A continuous pultrusion molding process combined with a two-layer co-extrusion process is used to prepare the light-triggered self-healing fiberglass tile as described in any one of claims 1-5. The specific processing steps are as follows: S1. Material Preparation: Prepare resin matrix material and surface layer material separately according to the specified proportions; the surface layer material is prepared by mixing a mixed system containing unsaturated polyester resin, polymerizable repair monomer, cationic photoinitiator and photosensitizer with curing agent and accelerator until homogeneous; the resin matrix material is an unsaturated polyester resin system without polymerizable repair monomer, cationic photoinitiator and photosensitizer, containing only resin, curing agent and accelerator to ensure the structural strength of the resin matrix; S2. Co-extrusion treatment: A double-layer co-extrusion device is used to extrude the resin matrix material and the surface layer material simultaneously; S3. Curing and molding: The double-layer composite material obtained in S2 is fed into a heated mold, and the mold temperature is controlled at 120~150℃ for constant temperature curing and molding. S4. Traction molding: After the material in the mold has completely solidified, the molded fiberglass tile is pulled out of the mold at a traction speed of 0.5 to 1.5 m / min. After natural cooling to room temperature, the photo-triggered self-healing fiberglass tile is obtained.

9. A method for repairing surface damage of light-triggered self-healing fiberglass roofing sheets, characterized in that, The specific operation for repairing the light-triggered self-healing fiberglass tile according to any one of claims 1-7 is as follows: use an ultraviolet LED lamp with a wavelength of 365nm to irradiate the damaged area of ​​the fiberglass tile surface layer with a light intensity of 50-100mW / cm² for 60-120 seconds; after irradiation, place the fiberglass tile in a room temperature environment for 30 minutes to allow the polymerizable repair monomers to fully complete the polymerization reaction, thereby achieving efficient repair of surface damage.

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