A photocurable self-repairing coating and car cover protective film and preparation method and application thereof

Abstract

The present invention discloses a photocurable self-repairing coating and a car cover protective film, and a preparation method and application thereof. The coating comprises raw materials of the following components: a main resin, a photoinitiator, a thermosetting agent, a reactive diluent, an auxiliary agent, and a solvent; the main resin comprises a mixture of a thermosetting resin and a photocurable resin. The present invention simultaneously introduces a resin with a photoinitiating group and a resin with a thermosetting group, so that the main body of the coating has the self-repairing performance and weather resistance of a thermosetting coating, and the surface has the antifouling property and glossiness of a photocurable coating; at the same time, the mixture of a linear resin and a bulk resin can well balance the softness and density of the coating.

Description

Technical Field

[0001] The present invention relates to the field of film processing, and in particular to a photocurable self-repairing coating and a car cover protective film, and a preparation method and application thereof. Background Art

[0002] Car cover film, also known as "invisible car cover", is a transparent or translucent film used to protect the car surface from various damages. It has three main effects. First, it protects the car surface from damages such as sand and gravel, acid rain, bird droppings and oil stains. Second, it improves the appearance of the car body. Generally, car cover film can enhance the gloss of the car paint and make the car body look more beautiful. Third, it extends the service life of the car paint. Car cover film can absorb ultraviolet light and reduce the damage of ultraviolet light to the car paint.

[0003] Currently, the self-repairing coating category of car cover films on the market is mainly thermosetting coating. The main component of thermosetting self-repairing coating is high molecular weight resin, which has high density and is easy for solution to penetrate, resulting in poor anti-fouling effect and difficulty in cleaning. At the same time, due to the characteristics of thermosetting, the degree of reaction during the coating process is low, resulting in poor weather resistance and easy yellowing. In addition, thermosetting coatings require a lot of heat to react during the reaction process, and the reaction time is slow. It usually takes 1-7 days to mature before the required performance can be achieved.

[0004] Photocuring coatings are used in more fields due to their cleanliness, high efficiency and excellent surface properties. The hydrophobicity, scratch resistance and stain resistance of photocuring coatings are all required properties for car cover products. However, photocuring products are rarely used outdoors. The main reason is that in the design of the coating, in order to ensure the degree of curing of the coating, excessive photoinitiators are added. Excessive photoinitiators continue to react under the ultraviolet rays in outdoor sunlight, resulting in super-curing and weakening the performance of the coating. At the same time, most photoinitiators are yellow, which will cause the initial yellow value of the product to be large.

[0005] Therefore, technicians in this field are committed to developing a light-cured coating car cover protective film with strong anti-fouling ability and good weather resistance. Summary of the invention

[0006] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide a car cover protective film with a photocuring self-repairing coating. Starting from the coating formula, it not only improves the common yellow value problem of the photocuring coating, but also ensures hydrophobicity, scratch resistance and stain resistance while also having excellent weather resistance and self-repairing properties.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] A photocurable self-repairing coating, comprising the following raw materials: a main resin, a photoinitiator, a thermal curing agent, an active diluent, an auxiliary agent, and a solvent;

[0009] The main resin includes a mixture of a thermosetting resin and a light-curing resin.

[0010] Preferably, the main resin includes a thermosetting resin and a photocurable resin mixed in a mass ratio of 1:0.5-2; the thermosetting resin includes a linear thermosetting resin; and the photocurable resin includes a bulk photocurable resin.

[0011] Preferably, the linear thermosetting resin includes a modified polyurethane oligomer; the molecular weight of the modified polyurethane oligomer includes 100~2000; the hydroxyl value of the modified polyurethane oligomer includes 3~30mgKOH / g; the bulk photocurable resin includes an acrylic modified polyurethane oligomer; the molecular weight of the acrylic modified polyurethane oligomer includes 1000~3000; the photocurable group of the modified polyurethane oligomer includes one or more of an unsaturated double bond and an epoxy group.

[0012] Preferably, the raw materials include the following mass fractions:

[0013] The thermosetting resin: 20 wt%~40wt%;

[0014] The photocurable resin: 20 wt%~40wt%;

[0015] The photoinitiator: 1wt%~30wt%;

[0016] The thermal curing agent: 1wt%~30wt%;

[0017] The active diluent: 10wt%~20wt%;

[0018] The auxiliary agent: 0.1wt%~10wt%;

[0019] The solvent: 1wt%~10wt%.

[0020] Preferably, the photoinitiator includes one or more of 2-[(2-oxo-2-phenylacetoxy)ethoxy]ethyl 2-oxo-2-phenylacetate, α-hydroxyketone, and monoacylphosphine oxide; the thermal curing agent includes one or more of amine curing agents, isocyanate curing agents, or other suitable types; the reactive diluent includes one or more of β-hydroxyethyl methacrylate, 1,6-hexanediol diglycidyl ether, or other suitable types; the auxiliary agent includes one or more of antioxidants, leveling agents, adhesion promoters, anti-aging aids, fillers, or other suitable types; the antioxidant includes one or more of free radical absorbers, metal ion chelators, hindered phenol antioxidants, enzyme antioxidants, or other suitable types; the filler includes one or more of fluorine fillers, silicone fillers, or other suitable types; the solvent includes one or more of ethyl acetate and butanone, or other suitable types.

[0021] A method for preparing the above-mentioned light-cured self-repairing coating comprises the following steps:

[0022] A. Stir the raw materials evenly according to the proportion to obtain the coating liquid;

[0023] B. applying the coating solution and then thermally curing it to obtain a primary coating;

[0024] C. Photocuring the primary coating to obtain the photocurable self-repairing coating.

[0025] Preferably, in step A, the stirring speed is 100-500 rpm, and the stirring time is 0.5-2 hours; in step B, the thermal curing temperature is 70-90°C, and the thermal curing time is 2-8 minutes; in step C, the wavelength of the photocuring is 280-400 nanometers, and the energy of the photocuring is 400-1200 millijoules / square centimeter.

[0026] An application of the above-mentioned light-cured self-repairing coating is used as a car cover protective film.

[0027] A car cover protective film obtained by applying the above-mentioned light-curing self-repairing coating comprises a release film layer, a mounting adhesive layer, a substrate layer and the light-curing self-repairing coating arranged in sequence.

[0028] The product structure of the car cover protective film, according to the installation direction, includes: installation glue, substrate, light-cured self-repairing coating from the inside to the outside. The release film needs to be torn off first during construction.

[0029] Preferably, the release film layer includes one or more of PET, CPP, PO or other suitable types, and the thickness includes 20~200μm; the mounting adhesive layer includes a mixture of one or more of acrylate resin, polyurethane resin or other suitable types and a tackifier, and the thickness includes 5~50μm; the substrate layer includes one or more of TPU, PET or other suitable types, and the thickness includes 50~200μm; the thickness of the photocurable self-repairing coating includes 3~10μm; the car cover protective film also includes a protective film layer arranged on the photocurable self-repairing coating; the protective film layer includes one or more of PET, CPP, PO or other suitable types, and the thickness includes 50-150μm.

[0030] A protective film can be added on top of the light-curing self-repairing coating of the car cover protective film as needed. The material of the protective film can be PET material, CPP material, PO material or other suitable film material, and the thickness is between 50 and 150 μm.

[0031] The implementation of the present invention has the following beneficial effects:

[0032] 1. Traditional photocuring and thermosetting car cover protective film coating systems, thermosetting coatings have good weather resistance and excellent self-repairing properties; but poor anti-fouling properties, and complex processing procedures, requiring a protective film to enter subsequent production; photocuring coatings have excellent processing properties, good anti-fouling effects, high gloss, and can be formed in one step; but weather resistance and repair properties are not as good as thermosetting coatings; the present invention simultaneously introduces resins with photoinitiating groups and resins with thermosetting groups, so that the coating body has the self-repairing properties and weather resistance of thermosetting coatings, and the surface has the anti-fouling properties and glossiness of photocuring coatings; at the same time, the mixture of linear resins and bulk resins can well balance the softness and density of the coating.

[0033] 2. The self-repairing coating of the present invention uses a photocuring system, which reduces the surface tension of the coating, improves the anti-fouling effect of the coating, and makes the car cover film easy to clean.

[0034] 3. The unique design of the resin and dual curing agent / initiator of the present invention reduces the yellow value of the coating and improves the weather resistance of the coating.

[0035] 4. The self-repairing coating of the present invention can be prepared by a stirring process. The stirring speed of the stirrer is 100-500 rpm, and the stirring time is 0.5-2 hours. The stirring process is simple to operate and is suitable for industrial production applications.

[0036] 5. The dual curing method of light curing and heat curing is adopted, which greatly improves the production efficiency compared with simple heat curing. Among them, the heat curing process uses a temperature of 70~90 degrees Celsius and a time of 2~8 minutes; the light curing process uses a UV lamp in the 280~400 nanometer band, and the energy required for curing is 400 millijoules / square centimeter to 1200 millijoules / square centimeter, which can obtain a self-healing coating with complete performance without the need for a 1~7-day aging process.

[0037] 6. Conventional car covers, whether light-cured or heat-cured, will be damaged by long-term sunlight exposure, so light stabilizers need to be added. However, the present invention combines heat curing and light curing, with the heat-curing resin attached to the light-curing resin, and provides self-repairing properties by relying on the characteristics of the heat-curing resin; under long-term sunlight, the light-curing resin slowly cross-links and cures, enhancing the overall coating hardness, allowing the light-curing resin to further react and more tightly interweave and adhere to the heat-curing resin, while enhancing the overall coating's scratch resistance. Therefore, this application does not require the addition of light stabilizers.

[0038] 7. The self-repairing light-curing coating of the car cover film uses low molecular weight acrylic or polyurethane resin, which has strong anti-penetration ability, excellent anti-fouling effect, and is easy to clean and maintain. At the same time, antioxidants are added to the light-curing coating to reduce the yellow value of the coating, improve the overall aesthetics of the car cover protective film, and enhance the weather resistance of the car cover protective film. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of a car cover protective film with a photocurable coating provided by the present invention, wherein 1-self-repairing coating, 2-substrate layer, 3-installation adhesive layer, 4-release film layer, 5-protective film layer. DETAILED DESCRIPTION

[0040] Example 1

[0041] like Figure 1 As shown, a car cover protective film includes a release film layer, a mounting adhesive layer, a substrate layer, a coating layer, and a protective film layer which are arranged in sequence.

[0042] Among them, the raw materials of the coating are as follows:

[0043] Linear thermosetting resin: 30wt%

[0044] Bulk photocurable resin: 30wt%

[0045] Photoinitiator: 10wt%

[0046] Thermal curing agent: 10wt%

[0047] Active diluent: 13wt%

[0048] Additive: 2wt%

[0049] Solvent: 5wt%.

[0050] In this embodiment, the linear thermosetting resin is Sartomer N310NS resin as an example for the experiment. The bulk photocurable resin is Sartomer CN996 NS resin as an example for the experiment. The photoinitiator is 2-[(2-oxo-2-phenylacetoxy)ethoxy]ethyl 2-oxo-2-phenylacetate, α-hydroxyketone, and monoacylphosphine oxide, which are compounded in a ratio of 1:2:3. The thermosetting agent is an amine curing agent. The active diluent is β-hydroxyethyl methacrylate. The additives include antioxidants, leveling agents, adhesion promoters, anti-aging additives and fillers. The antioxidant is a free radical absorber. The filler is a fluorine filler. The solvent is ethyl acetate.

[0051] The preparation of the coating includes the following steps:

[0052] A. Stir the raw materials uniformly according to the proportion, the stirring speed of the stirrer is 300 rpm, the stirring time is 1 hour, and a coating liquid is obtained;

[0053] B. After applying the coating liquid, heat curing is performed at a temperature of 80 degrees Celsius for 6 minutes to obtain a primary coating;

[0054] C. The primary coating is photocured using a UV lamp in the 280-400 nm band with an energy of 800 mJ / cm2 to obtain the coating.

[0055] The release film layer is made of PET material with a thickness of 120μm. The installation adhesive layer is made of acrylic resin with a matching tackifier added, and the adhesive layer thickness is 35μm. The substrate layer is TPU with a thickness of 120μm. The thickness of the light-cured self-healing coating is 6μm. The protective film layer is made of PET material with a thickness of 120μm.

[0056] Example 2

[0057] like Figure 1 As shown, a car cover protective film includes a release film layer, a mounting adhesive layer, a substrate layer, a coating layer, and a protective film layer which are arranged in sequence.

[0058] Among them, the raw materials of the coating are as follows:

[0059] Linear thermosetting resin: 20 wt%

[0060] Bulk photocurable resin: 40wt%

[0061] Photoinitiator: 30wt%

[0062] Thermal curing agent: 1wt%

[0063] Active diluent: 5.9wt%

[0064] Additives: 0.1wt%

[0065] Solvent: 3wt%.

[0066] In this embodiment, the linear thermosetting resin is Sartomer N310NS resin as an example for the experiment. The bulk photocurable resin is Sartomer CN996 NS resin as an example for the experiment. The photoinitiator is 2-[(2-oxo-2-phenylacetoxy)ethoxy]ethyl 2-oxo-2-phenylacetate, α-hydroxyketone, and monoacylphosphine oxide compounded in a ratio of 1:1:1. The thermosetting agent is an isocyanate curing agent. The active diluent is 1,6-hexanediol diglycidyl ether. The additives include antioxidants, leveling agents, adhesion promoters, anti-aging additives and fillers. The antioxidant is a metal ion chelating agent. The filler is a silicone filler. The solvent is butanone.

[0067] The preparation of the coating includes the following steps:

[0068] A. Stir the raw materials uniformly according to the proportion, the stirring speed of the stirrer is 100 rpm, the stirring time is 2 hours, and a coating liquid is obtained;

[0069] B. After applying the coating liquid, heat curing is performed at a temperature of 90 degrees Celsius for 2 minutes to obtain a primary coating;

[0070] C. The primary coating is photocured using a UV lamp in the 280-400 nm band with an energy of 1200 mJ / cm2 to obtain the coating.

[0071] The release film layer is made of CPP material with a thickness of 20μm. The mounting adhesive layer is made of polyurethane resin with a matching tackifier added, and the adhesive layer thickness is 50μm. The substrate layer is PET with a thickness of 50μm. The thickness of the light-cured self-healing coating is 3μm. The protective film layer is made of CPP material with a thickness of 150μm.

[0072] Example 3

[0073] like Figure 1 As shown, a car cover protective film includes a release film layer, a mounting adhesive layer, a substrate layer, a coating layer, and a protective film layer which are arranged in sequence.

[0074] Among them, the raw materials of the coating are as follows:

[0075] Linear thermosetting resin: 40wt%

[0076] Bulk photocurable resin: 20 wt%

[0077] Photoinitiator: 1wt%

[0078] Thermal curing agent: 25wt%

[0079] Active diluent: 10wt%

[0080] Additives: 3wt%

[0081] Solvent: 1wt%.

[0082] In this embodiment, the linear thermosetting resin is Sartomer N310NS resin as an example for the experiment. The bulk photocurable resin is Sartomer CN996 NS resin as an example for the experiment. The photoinitiator is 2-[(2-oxo-2-phenylacetoxy)ethoxy]ethyl 2-oxo-2-phenylacetate, α-hydroxyketone, and monoacylphosphine oxide, which are compounded in a ratio of 3:2:1. The thermosetting agent is an amine curing agent. The active diluent is β-hydroxyethyl methacrylate. The additives include antioxidants, leveling agents, adhesion promoters, anti-aging additives and fillers. The antioxidant is a hindered phenol antioxidant. The filler is a silicone filler. The solvent is ethyl acetate.

[0083] The preparation of the coating includes the following steps:

[0084] A. Stir the raw materials uniformly according to the proportion, the stirring speed of the stirrer is 500 rpm, and the stirring time is 0.5 hour to obtain a coating liquid;

[0085] B. After applying the coating liquid, heat curing is performed at a temperature of 70 degrees Celsius for 8 minutes to obtain a primary coating;

[0086] C. The primary coating is photocured using a UV lamp in the 280-400 nm band with an energy of 400 mJ / cm2 to obtain the coating.

[0087] The release film layer is made of PO material with a thickness of 200μm. The installation adhesive layer is made of acrylic resin with a matching tackifier added, and the adhesive layer thickness is 5μm. The substrate layer is TPU with a thickness of 200μm. The thickness of the light-cured self-healing coating is 10μm. The protective film layer is made of PO material with a thickness of 50 μm.

[0088] Example 4

[0089] like Figure 1 As shown, a car cover protective film includes a release film layer, a mounting adhesive layer, a substrate layer, a coating layer, and a protective film layer which are arranged in sequence.

[0090] Among them, the raw materials of the coating are as follows:

[0091] Linear thermosetting resin: 20 wt%

[0092] Bulk photocurable resin: 20 wt%

[0093] Photoinitiator: 1wt%

[0094] Thermal curing agent: 30wt%

[0095] Active diluent: 11wt%

[0096] Additives: 10wt%

[0097] Solvent: 8wt%.

[0098] In this embodiment, the linear thermosetting resin is Sartomer N310NS resin as an example for the experiment. The bulk photocurable resin is Sartomer CN996 NS resin as an example for the experiment. The photoinitiator is 2-[(2-oxo-2-phenylacetoxy)ethoxy]ethyl 2-oxo-2-phenylacetate, α-hydroxyketone, and monoacylphosphine oxide compounded in a ratio of 1:2:2. The thermosetting agent may be an amine curing agent and an isocyanate curing agent. The active diluent is β-hydroxyethyl methacrylate. The additives include antioxidants, leveling agents, adhesion promoters, anti-aging additives, and fillers. The antioxidant is an enzyme antioxidant. The filler is a silicone filler. The solvent is butanone.

[0099] The preparation of the coating includes the following steps:

[0100] A. Stir the raw materials uniformly according to the proportion, the stirring speed of the stirrer is 250 rpm, and the stirring time is 1.5 hours to obtain a coating liquid;

[0101] B. After applying the coating liquid, heat curing is performed at a temperature of 75 degrees Celsius for 6 minutes to obtain a primary coating;

[0102] C. The primary coating is photocured using a UV lamp in the 280-400 nm band with an energy of 600 mJ / cm2 to obtain the coating.

[0103] The release film layer is made of PET material with a thickness of 80μm. The installation adhesive layer is made of polyurethane resin with a matching tackifier added, and the adhesive layer thickness is 35μm. The substrate layer is TPU with a thickness of 80μm. The thickness of the light-cured self-repairing coating is 5μm. The protective film layer is made of PET material with a thickness of 80μm.

[0104] Example 5

[0105] like Figure 1 As shown, a car cover protective film includes a release film layer, a mounting adhesive layer, a substrate layer, a coating layer, and a protective film layer which are arranged in sequence.

[0106] Among them, the raw materials of the coating are as follows:

[0107] Linear thermosetting resin: 26wt%

[0108] Bulk photocurable resin: 24wt%

[0109] Photoinitiator: 4wt%

[0110] Thermal curing agent: 9wt%

[0111] Active diluent: 20wt%

[0112] Additives: 7wt%

[0113] Solvent: 10wt%.

[0114] In this embodiment, the linear thermosetting resin is Sartomer N310NS resin as an example for the experiment. The bulk photocurable resin is Sartomer CN996 NS resin as an example for the experiment. The photoinitiator is 2-[(2-oxo-2-phenylacetoxy)ethoxy]ethyl 2-oxo-2-phenylacetate, α-hydroxyketone, and monoacylphosphine oxide compounded in a ratio of 2:2:3. The thermosetting agent is an isocyanate curing agent. The active diluent is 1,6-hexanediol diglycidyl ether. The additives include antioxidants, leveling agents, adhesion promoters, anti-aging additives and fillers. The antioxidant is a free radical absorber. The filler is a fluorine filler. The solvent is butanone.

[0115] The preparation of the coating includes the following steps:

[0116] A. Stir the raw materials uniformly according to the proportion, the stirring speed of the stirrer is 450 rpm, the stirring time is 1 hour, and a coating liquid is obtained;

[0117] B. After applying the coating liquid, heat curing is performed at a temperature of 85 degrees Celsius for 3 minutes to obtain a primary coating;

[0118] C. The primary coating is photocured using a UV lamp in the 280-400 nm band with an energy of 700 mJ / cm2 to obtain the coating.

[0119] The release film layer is made of CPP material with a thickness of 80μm. The mounting adhesive layer is made of acrylic resin with a matching tackifier added, and the adhesive layer thickness is 20μm. The substrate layer is PET with a thickness of 800μm. The thickness of the light-cured self-healing coating is 8μm. The protective film layer is made of CPP material with a thickness of 80μm.

[0120] Effect Example 1

[0121] The car cover products prepared in Examples 1 to 5 were compared with two commercially available products in terms of performance testing, wherein the performance testing methods and standards are as follows:

[0122] Hardness: ASTM D2240;

[0123] Gloss (60°): DIN 67530;

[0124] Scratch resistance: Use a copper brush to brush the coating surface back and forth once, and observe the scratch depth under a microscope;

[0125] Stain resistance: Wipe with a M&G oily double-jaw pen to see the mark left;

[0126] Wear (wear resistance) experiment in repair performance: Mingyu instrument MODEL: 339, steel wool rubs back and forth 10 times, pressure 1KG, speed 60 times / min;

[0127] ΔL in repair performance: The brightness L of the car cover is related to the smoothness of the coating surface. ΔL indicates the change in brightness before and after the wear test, which can show the self-repairing ability of the coating. ΔL = initial brightness L1 - brightness L2 after the wear test. There is no obvious change or no change in brightness before and after the wear test. The smaller ΔL is, the stronger the self-repairing performance of the coating is.

[0128] Initial yellow value: measured by Shimadzu spectrophotometer UV3600;

[0129] Yellowing resistance: After undergoing QUV aging and high temperature and high humidity aging, measured with Japan Shimadzu spectrophotometer UV3600; QUV aging: 1.00W / m2 @340nm, 50℃, 8 hours of light + 3 hours and 45 minutes of darkness + 15 minutes of spraying, 500 hours of cycle; high temperature and high humidity aging: 85℃, 85%H, 500 hours.

[0130] The results are shown in Table 1:

[0131] Table 1

[0132]

[0133] It can be seen from the test results in Table 1 that the two commercially available products are not as good as the products prepared in Examples 1 to 5 in terms of hardness, glossiness, scratch resistance, stain resistance, and yellowing resistance. More importantly, in terms of repair performance, the two commercially available products cannot be modified by themselves and need to be repaired under heat treatment such as hot water pouring, but the repair ΔL is large and the repair effect is not satisfactory. The products prepared in Examples 1 to 5 can complete self-repair after a short placement of 0.5h at room temperature after wear, and the repair ΔL is small, and the repair effect is better. It is speculated that the reason for the above difference is related to the cross-linking and curing of the thermosetting resin and the light-curing resin in the present invention. Comprehensive evaluation of the products prepared in Examples 1 to 5 shows that Example 1 is slightly better than Examples 2 to 5 in all aspects of performance and should be considered a better choice.

[0134] Effect Example 2

[0135] The products prepared in Examples 1 to 5 and two commercially available products were compared in terms of performance before and after product repair. The experiment was set up as follows:

[0136] The products prepared in Examples 1 to 5 and two commercially available products were divided into two parts, one for direct performance testing and the other for repair after abrasion (wear resistance) test. The repaired products were subjected to performance testing and the performance of the repaired products was compared with that of the original products.

[0137] The repair process of the products prepared in Examples 1 to 5 is: self-repair after being placed at room temperature for 0.5 hours. The repair process of the two commercially available products is: heat treatment and repair by pouring hot water.

[0138] The results are shown in Table 2:

[0139] Table 2

[0140]

[0141] From the test results in Table 2, it can be seen that the two commercially available products cannot complete the repair by themselves and need to be repaired under heat treatment such as hot water pouring, but the performance after repair is significantly reduced compared with the original product, which affects the life of the car cover and the subsequent protective effect. The products prepared in Examples 1 to 5 can complete self-repair after a short placement of 0.5 hours at room temperature after wear, and the performance after repair is almost the same as the original product, which can better play a protective role in the future. The reason for the above difference is speculated: the present invention cross-links and cures the thermosetting resin and the photocuring resin with each other, and relies on the characteristics of the thermosetting resin to provide self-repair performance; under long-term sunlight, the photocuring resin slowly cross-links and cures, enhancing the overall coating hardness, allowing the photocuring resin to further react and more closely interweave and fit the thermosetting resin, while enhancing the scratch resistance of the overall coating, thereby achieving self-repair after placement and keeping the performance after repair basically consistent with the original product.

[0142] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A photocurable self-repairing coating, characterized in that: The raw materials include the following components: main resin, photoinitiator, thermal curing agent, active diluent, auxiliary agent, solvent; The main resin is a mixture of a heat-curing resin and a light-curing resin; the heat-curing resin is a linear heat-curing resin; and the light-curing resin is a bulk light-curing resin; The linear thermosetting resin is a modified polyurethane oligomer; The molecular weight of the modified polyurethane oligomer is 100-2000; the hydroxyl value of the modified polyurethane oligomer is 3-30 mgKOH / g; the bulk photocurable resin is an acrylic acid modified polyurethane oligomer; the molecular weight of the acrylic acid modified polyurethane oligomer is 1000-3000; the photocurable group of the modified polyurethane oligomer includes one or more of an unsaturated double bond and an epoxy group; In the main resin, the thermosetting resin and the light-curing resin are mixed in a mass ratio of 1:0.5-2; The photocurable self-repairing coating comprises the following raw materials by mass fraction: The thermosetting resin: 20 wt%~40wt%; The photocurable resin: 20 wt%~40wt%; The photoinitiator: 1wt%~30wt%; The thermal curing agent: 1wt%~30wt%; The active diluent: 10wt%~20wt%; The auxiliary agent: 0.1wt%~10wt%; The solvent: 1wt%~10wt%.

2. The light-cured self-repairing coating according to claim 1, characterized in that: The photoinitiator includes one or more of 2-[(2-oxo-2-phenylacetoxy)ethoxy]ethyl 2-oxo-2-phenylacetate, α-hydroxyketone, and monoacylphosphine oxide; the thermal curing agent includes one or more of amine curing agents and isocyanate curing agents; the active diluent includes one or more of β-hydroxyethyl methacrylate and 1,6-hexanediol diglycidyl ether; the auxiliary agent includes one or more of antioxidants, leveling agents, adhesion promoters, anti-aging additives, and fillers; the antioxidant includes one or more of free radical absorbers, metal ion chelating agents, hindered phenol antioxidants, and enzyme antioxidants; the filler includes one or more of fluorine fillers and silicone fillers; the solvent includes one or more of ethyl acetate and butanone.

3. A method for preparing a light-cured self-repairing coating as claimed in claim 1, characterized in that: The steps include: A. Stir the raw materials evenly according to the proportion to obtain the coating liquid; B. applying the coating solution and then thermally curing it to obtain a primary coating; C. Photocuring the primary coating to obtain the photocurable self-repairing coating.

4. The method for preparing the light-cured self-repairing coating according to claim 3, characterized in that: In step A, the stirring speed is 100-500 rpm, and the stirring time is 0.5-2 hours; in step B, the temperature of the thermal curing is 70-90°C, and the time of the thermal curing is 2-8 minutes; in step C, the wavelength of the photocuring is 280-400 nanometers, and the energy of the photocuring is 400-1200 millijoules / square centimeter.

5. An application of the light-cured self-repairing coating as claimed in claim 1, characterized in that: Used as a protective film for car covers.

6. A car cover protective film obtained by applying the light-cured self-repairing coating as claimed in claim 1, characterized in that: It comprises a release film layer, a mounting adhesive layer, a substrate layer and the light-curing self-repairing coating which are arranged in sequence.

7. The car cover protective film according to claim 6, characterized in that: The release film layer includes one or more of PET, CPP, and PO, with a thickness of 20~200μm; the mounting adhesive layer includes a mixture of one or more of acrylate resin, polyurethane resin and a tackifier, with a thickness of 5~50μm; the substrate layer includes one or more of TPU and PET, with a thickness of 50~200μm; the photocurable self-repairing coating has a thickness of 3~10μm; the car cover protective film also includes a protective film layer arranged on the photocurable self-repairing coating; the protective film layer includes one or more of PET, CPP, and PO, with a thickness of 50~150μm.

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