An electron beam-cured composite sheet and method of making the same

Abstract

The application relates to the technical field of PETG sheet materials, in particular to a composite sheet based on electron beam curing and a preparation method thereof, wherein the composite sheet based on electron beam curing comprises a PETG substrate and a coating layer attached to the substrate; the coating layer comprises the following raw materials in parts by weight: 50-70 parts of polyurethane acrylate, 1-3 parts of a bifunctional fluorine-containing acrylate monomer, 15-25 parts of a bifunctional active diluent, 3-6 parts of trimethylolpropane triacrylate, 10-15 parts of modified silicon carbide, 1-2 parts of a dispersing agent and 1-2 parts of a leveling agent; and the composite sheet prepared by the application has the four-resistance properties of wear resistance, weather resistance, scratch resistance and corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of PETG sheet technology, specifically to a composite sheet based on electron beam curing and its preparation method. Background Technology

[0002] PETG, or polyethylene terephthalate-1,4-cyclohexanediol ester, is an amorphous copolyester with advantages such as high transparency (transmittance > 90%), ease of processing, and environmental friendliness, making it widely used in packaging, medical, home appliance, and decoration industries. However, pure PETG suffers from drawbacks such as low hardness, susceptibility to scratches, insufficient chemical and weather resistance, and aging with long-term use, limiting its application in high-end applications. Therefore, coatings are often prepared on its surface to address these issues. Traditional surface modification involves UV curing, which relies on photoinitiators and suffers from problems such as yellowing, uneven deep curing, and VOC residues. Furthermore, thermal curing is energy-intensive, inefficient, and prone to causing sheet deformation. Compared to UV curing, EB curing does not require photoinitiators, offers faster curing speeds, lower energy consumption, and is more environmentally friendly. It can achieve three-dimensional uniform curing, and the resulting coating has a high cross-linking density, significantly improving the "four resistances" (chemical resistance, chemical resistance, and weather resistance), aligning with the needs of green manufacturing and high-end material upgrades.

[0003] Patent CN114806387A discloses a PETG coating and its raw material composition, which, by weight percentage, comprises 20-30% hexafunctional polyurethane acrylate, 35-45% trifunctional polyurethane acrylate, 10-20% bifunctional active monomer, 5-10% silica powder, 0.5-2% Teflon powder, 1-3% nano-alumina powder, 1-3% matting agent, 1-2% UV absorber, and the balance being additives. The PETG matte film product prepared by this invention solves the problems of traditional UV matte coatings, such as high VOC emissions, poor UV aging resistance, poor micro-scratch resistance, and easy scratching, which are caused by the need for a matte effect. It achieves a matte effect using an excimer lamp, and by selectively combining active monomers with low-functionality polyurethane acrylate, it reduces gloss while maintaining adhesion to PETG, and ensures micro-scratch resistance and transparency. However, high-functionality polyurethane acrylates have high viscosity, and when combined with multiple powders, the system has poor flowability. Nano-alumina and silica powder are prone to agglomeration, which may lead to poor coating smoothness and uneven wear resistance.

[0004] Patent CN116970201A discloses a composite film based on electron beam curing and its preparation method. The composite film includes a substrate, a transition layer, and an EB coating sequentially disposed on the substrate. The transition layer is obtained by curing a transition coating, which comprises the following components by weight: 40-60 parts acrylic resin; 15-25 parts cellulose acetate butyrate resin; 3-10 parts isopropanol; 10-20 parts n-propyl acetate; 1-5 parts inorganic pigment; and 1-6 parts first additive. The EB coating is obtained by curing the EB coating. Implementing this invention can improve the fineness of decorative patterns and the yellowing resistance of the composite film. However, although cellulose acetate butyrate resin has good film-forming properties and compatibility, it may have drawbacks such as a relatively soft coating and unsatisfactory scratch and solvent resistance.

[0005] Therefore, there is an urgent need in the market for a composite sheet material that is wear-resistant, weather-resistant, scratch-resistant, and corrosion-resistant, as well as its preparation method. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of this invention is to obtain a composite sheet based on electron beam curing with excellent wear resistance, weather resistance, scratch resistance and corrosion resistance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a composite sheet based on electron beam curing, comprising a PETG substrate and a coating attached thereto. The coating is applied to the surface of the PETG substrate and cured by electron beam to form a fixed film. The coating comprises the following raw materials in parts by weight: 50-70 parts of polyurethane acrylate, 1-3 parts of bifunctional fluorinated acrylate monomer, 15-25 parts of bifunctional reactive diluent, 3-6 parts of trimethylolpropane triacrylate, 10-15 parts of modified silicon carbide, 1-2 parts of dispersant, and 1-2 parts of leveling agent.

[0008] This application describes an EB-cured coating prepared by compounding polyurethane acrylate, bifunctional fluorinated acrylate monomers, bifunctional reactive diluents, trimethylolpropane triacrylate, modified silicon carbide, dispersants, and leveling agents. The polyurethane acrylate, fluorinated acrylate monomers, bifunctional reactive diluents, and trimethylolpropane triacrylate can form a highly cross-linked, dense network under electron beam curing. The high energy of the electron beam can penetrate and activate the surface layer of the PETG substrate, forming strong physical anchoring or weak chemical bonding, resulting in excellent adhesion between the substrate and the coating. Modified silicon carbide provides wear resistance, high temperature resistance, corrosion resistance, and high thermal stability, protecting the substrate. The addition of dispersants and leveling agents improves the processing performance and appearance of the sheet. The synergistic effect of these substances gives the composite sheet the "four resistances" characteristics: wear resistance, weather resistance, scratch resistance, and corrosion resistance.

[0009] In some embodiments, the fluorinated acrylate monomer is 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane.

[0010] This application introduces fluorinated monomers into the coating to achieve a low surface energy and reduce stain adhesion. The preferred fluorinated monomer is 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane, which contains two acrylate bonds and can participate in the electron beam curing reaction. This allows the fluorinated segments to be directly inserted into the crosslinking network of the coating, further improving the coating's corrosion resistance. Furthermore, the fluorinated segments do not easily migrate to the coating surface, resulting in strong adhesion between the coating and the PETG substrate.

[0011] In some embodiments, the bifunctional active diluent is one or more of tripropylene glycol diacrylate, dipropylene glycol diacrylate, and 1,6-hexanediol diacrylate.

[0012] Preferably, the bifunctional active diluent is tripropylene glycol diacrylate.

[0013] In some embodiments, the method for preparing the modified silicon carbide includes the following steps: A1. Add lanthanum nitrate to a 70-80 wt% aqueous ethanol solution and stir for 3-5 min. Add citric acid and ethylene glycol, stir at 60-70°C for 20-40 min, and adjust the pH to 1.5-2 to obtain a sol. A2. Add silicon carbide to the sol obtained in step A1, sonicate for 30-50 minutes, stir for 1-3 hours, evaporate by rotary evaporation, and dry to obtain powder; A3. The powder obtained in step A2 is heated to 700-800°C at a rate of 4-6°C / min and held for 1-1.5h. It is then cooled to room temperature in the furnace, ground, and sieved to obtain rare earth-silicon carbide composite. A4. The rare earth-silicon carbide composite obtained in step A3 is washed with 0.1-0.5 mol / L sodium hydroxide aqueous solution and then added to 78-90 wt% ethanol aqueous solution with a silane coupling agent containing double bonds. The mixture is stirred at 50-60°C for 1-2 h and then dried to obtain modified silicon carbide.

[0014] Preferably, the ratio of lanthanum nitrate to 70-80 wt% aqueous ethanol solution is 1 g : (120-160) ml.

[0015] Preferably, the mass ratio of lanthanum nitrate to citric acid is 1:(0.64-0.68).

[0016] Preferably, the ratio of lanthanum nitrate to ethylene glycol is 1g:(0.25-0.35)ml.

[0017] Preferably, the ratio of the rare earth-silicon carbide composite and the 78-90wt% ethanol aqueous solution in step A4 is 1g:(20-40)ml.

[0018] This application describes a modified silicon carbide prepared by first constructing a lanthanum compound coating layer on the surface of silicon carbide and then reacting it with a silane coupling agent containing double bonds. Adding this modified silicon carbide to a coating can result in a coating with enhanced corrosion resistance, abrasion resistance, scratch resistance, and weather resistance. This is likely because: firstly, the rare earth layer acts as a transition layer, strengthening the bond between the modified silicon carbide and silane, while the silane coupling agent segments containing double bonds participate in the curing reaction. These two effects synergistically improve the dispersibility of the modified silicon carbide in the coating, thus enhancing the scratch resistance of the composite sheet. Secondly, rare earth oxides may form strong chemical bonds such as La-O-Si with the silica layer and resin on the silicon carbide surface. The interface formed by these strong chemical bonds is itself difficult for water, acids, alkalis, and other media to penetrate and destroy, delaying the penetration and stripping of corrosive media along the filler / resin interface. Simultaneously, these strong chemical bonds can more effectively "lock" the resin expansion within the rigid network composed of low-expansion silicon carbide and rare earth oxides, constraining the thermal movement of resin segments and thus reducing macroscopic thermal expansion. Rare earth oxides typically have a thermal expansion coefficient between that of silicon carbide and organic resins. As a transition layer, they can alleviate interfacial stress caused by thermal expansion coefficients, reduce the generation of microcracks, and make the overall dimensions of the coating more stable when heated.

[0019] In some embodiments, the silicon carbide is a combination of silicon carbide with a particle size of 2-10 μm and silicon carbide with a particle size of 200-500 nm.

[0020] Preferably, the mass ratio of silicon carbide with a particle size of 2-10 μm to silicon carbide with a particle size of 200-500 nm is 1:(0.3-0.6).

[0021] This application achieves optimal overall coating performance by adding silicon carbide of different particle sizes. This is likely because smaller particles can fill the gaps between larger particles, resulting in a denser packing. This reduces coating porosity, forming a denser physical barrier and significantly improving corrosion resistance, impermeability, and high-temperature resistance. Larger particles primarily provide skeletal support, enhancing hardness, abrasion resistance, and impact resistance. The two particle sizes of silicon carbide work synergistically, improving coating hardness and abrasion resistance while also enhancing its density, smoothness, and adhesion.

[0022] In some embodiments, the mass ratio of lanthanum nitrate to silicon carbide is 1:(5-10).

[0023] In some embodiments, the mass ratio of the rare earth-silicon carbide composite and the double-bonded silane coupling agent in step A4 is 1:(0.015-0.025).

[0024] In some embodiments, the double-bonded silane coupling agent is A-151 silane coupling agent and / or KH-570 silane coupling agent.

[0025] Preferably, the silane coupling agent containing double bonds is KH-570 silane coupling agent.

[0026] In some embodiments, the dispersant is a polycarboxylate dispersant.

[0027] This invention provides a method for preparing a composite sheet based on electron beam curing, comprising the following steps: S1. Add polyurethane acrylate, bifunctional fluorinated acrylate monomer, bifunctional reactive diluent, trimethylolpropane triacrylate, dispersant, and leveling agent into a reaction vessel, stir at 25-35°C for 30-60 minutes to obtain a mixture. S2. Add the modified silicon carbide to the mixture obtained in step S1, stir at 25-35°C for 20-30 minutes to obtain the coating. S3. The PETG substrate is corona-treated to a dyne value of 30-34 to obtain a pretreated PETG substrate; S4. Apply the coating obtained in step S2 onto the pretreated PETG substrate, with a coating amount of 10-12 g / m². 2 The composite sheet is obtained by curing with an electron beam curing machine.

[0028] Preferably, the parameters for curing by the electron beam curing machine are: accelerating voltage 150-180 keV, radiation dose 35-50 kGy, transmission line speed 20-50 m / min, and oxygen concentration <200 ppm.

[0029] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention obtains an EB curing coating by compounding polyurethane acrylate, fluorinated acrylate monomer, bifunctional active diluent, trimethylolpropane triacrylate, modified silicon carbide, dispersant and leveling agent, which is then coated on a PETG substrate and cured to form a composite sheet with wear resistance, weather resistance, scratch resistance and corrosion resistance.

[0030] (2) By introducing bifunctional fluorinated acrylate monomers into the coating, the present invention can directly insert fluorinated segments into the crosslinking network of the coating, which on the one hand further improves the corrosion resistance of the coating, and on the other hand, the fluorinated segments are not easy to migrate to the surface of the coating, so that the coating has strong adhesion to the PETG substrate.

[0031] (3) The modified silicon carbide prepared by first constructing a lanthanum compound coating layer on the surface of silicon carbide and then reacting it with a silane coupling agent containing double bonds can be added to the coating to make the coating more corrosion resistant, wear resistant, scratch resistant and weather resistant.

[0032] (4) The addition of two different particle sizes of silicon carbide in this invention can play a synergistic role, improving the coating's hardness and wear resistance while also improving its density, smoothness and adhesion. Detailed Implementation The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0034] In the following examples and comparative examples, the compounds and related reagents used were all commercially available. The polyurethane acrylate was FSP8296, purchased from Runao Chemical; the dispersant was BYK-154; and the leveling agent was BYK-300.

[0035] Preparation Example 1 The preparation method of modified silicon carbide-1 includes the following steps: A1. Add 1g of lanthanum nitrate to 140ml of 75wt% ethanol aqueous solution and stir for 4min. Add 0.66g of citric acid and 0.3ml of ethylene glycol, stir at 65°C for 30min, and adjust the pH to 1.8 with 0.5mol / L dilute nitric acid to obtain a sol. A2. Add 7g of silicon carbide to the sol obtained in step A1, sonicate for 40min, stir for 2h, evaporate by rotary evaporation, and dry at 60°C to obtain powder; A3. The powder obtained in step A2 is heated to 750°C at a rate of 5°C / min and held for 1.5h. It is then cooled to room temperature in the furnace, ground, and passed through a 500-mesh sieve to obtain a rare earth-silicon carbide composite. A4. Wash 5g of the rare earth-silicon carbide composite obtained in step A3 with 0.3mol / L sodium hydroxide aqueous solution, add 0.1g of KH-570 silane coupling agent to 150ml of 85wt% ethanol aqueous solution, stir at 55°C for 1.5h, and dry at 60°C to obtain modified silicon carbide-1.

[0036] The silicon carbide is a composition of silicon carbide with a particle size of 5 μm and silicon carbide with a particle size of 300 nm, with a mass ratio of 1:0.45.

[0037] Preparation Example 2 The preparation method of modified silicon carbide-2 is the same as that in preparation example 1, except that the amount of silicon carbide added is 12g.

[0038] Preparation Example 3 The preparation method of modified silicon carbide-3 is the same as that in preparation example 1, except that the amount of KH-570 silane coupling agent added is 0.17g.

[0039] Preparation Example 4 The preparation method of modified silicon carbide-4 is the same as that in preparation example 1, except that the particle size of silicon carbide is 5 μm.

[0040] Preparation Example 5 The preparation method of modified silicon carbide-5 includes the following steps: 5g of silicon carbide is washed with 0.3mol / L sodium hydroxide aqueous solution and then added to 150ml of 85wt% ethanol aqueous solution with 0.1g KH-570 silane coupling agent. The mixture is stirred at 55°C for 1.5h and dried at 60°C to obtain modified silicon carbide-5.

[0041] The silicon carbide is a composition of silicon carbide with a particle size of 5 μm and silicon carbide with a particle size of 300 nm, with a mass ratio of 1:0.45.

[0042] Example 1 An electron beam-cured composite sheet includes a PETG substrate and a coating attached thereto; the coating comprises the following raw materials in parts by weight: 60 parts polyurethane acrylate, 2 parts 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane, 20 parts tripropylene glycol diacrylate, 4.5 parts trimethylolpropane triacrylate, 112 parts modified silicon carbide-1, 1.5 parts dispersant, and 1.5 parts leveling agent.

[0043] This embodiment is based on a method for preparing composite sheets using electron beam curing, which includes the following steps: S1. Add polyurethane acrylate, 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane, tripropylene glycol diacrylate, trimethylolpropane triacrylate, dispersant, and leveling agent into a reaction vessel, stir at 30°C for 45 min to obtain a mixture. S2. Add modified silicon carbide-1 to the mixture obtained in step S1 and stir for 25 minutes to obtain the coating. S3. The PETG substrate is corona-treated to a dyne value of 32 to obtain a pretreated PETG substrate; S4. Apply the coating obtained in step S2 onto the pretreated PETG substrate, with a coating amount of 11 g / m². 2 The composite sheet is obtained by curing with an electron beam curing machine.

[0044] The parameters for curing using the electron beam curing machine are: accelerating voltage 160 keV, radiation dose 45 kGy, transmission line speed 30 m / min, and oxygen concentration 170 ppm.

[0045] Example 2 An electron beam-cured composite sheet includes a PETG substrate and a coating attached thereto; the coating comprises the following raw materials in parts by weight: 50 parts polyurethane acrylate, 1 part 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane, 15 parts tripropylene glycol diacrylate, 3 parts trimethylolpropane triacrylate, 10 parts modified silicon carbide-1, 1 part dispersant, and 1 part leveling agent.

[0046] This embodiment is based on a method for preparing composite sheets using electron beam curing, which includes the following steps: S1. Add polyurethane acrylate, 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane, tripropylene glycol diacrylate, trimethylolpropane triacrylate, dispersant, and leveling agent into a reaction vessel, stir at 25°C for 60 min to obtain a mixture. S2. Add modified silicon carbide-1 to the mixture obtained in step S1, stir at 25°C for 30 minutes to obtain the coating. S3. The PETG substrate is corona-treated to a dyne value of 32 to obtain a pretreated PETG substrate; S4. Apply the coating obtained in step S2 onto the pretreated PETG substrate, with a coating amount of 11 g / m². 2 The composite sheet is obtained by curing with an electron beam curing machine.

[0047] The parameters for curing using the electron beam curing machine are: accelerating voltage 160 keV, radiation dose 45 kGy, transmission line speed 30 m / min, and oxygen concentration 170 ppm.

[0048] Example 3 An electron beam-cured composite sheet includes a PETG substrate and a coating attached thereto; the coating comprises the following raw materials in parts by weight: 70 parts polyurethane acrylate, 3 parts 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane, 25 parts tripropylene glycol diacrylate, 6 parts trimethylolpropane triacrylate, 15 parts modified silicon carbide-1, 2 parts dispersant, and 2 parts leveling agent.

[0049] This embodiment is based on a method for preparing composite sheets using electron beam curing, which includes the following steps: S1. Add polyurethane acrylate, 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane, tripropylene glycol diacrylate, trimethylolpropane triacrylate, dispersant, and leveling agent into a reaction vessel, stir at 35°C for 30 min to obtain a mixture. S2. Add modified silicon carbide-1 to the mixture obtained in step S1, stir at 35°C for 20 minutes to obtain the coating. S3. The PETG substrate is corona-treated to a dyne value of 32 to obtain a pretreated PETG substrate; S4. Apply the coating obtained in step S2 onto the pretreated PETG substrate, with a coating amount of 11 g / m². 2 The composite sheet is obtained by curing with an electron beam curing machine.

[0050] The parameters for curing using the electron beam curing machine are: accelerating voltage 160 keV, radiation dose 45 kGy, transmission line speed 30 m / min, and oxygen concentration 170 ppm.

[0051] Example 4 A composite sheet based on electron beam curing and its preparation method are described. The specific implementation method is the same as in Example 1, except that modified silicon carbide-1 is replaced with modified silicon carbide-2 in equal amounts.

[0052] Example 5 A composite sheet based on electron beam curing and its preparation method are described. The specific implementation method is the same as in Example 1, except that modified silicon carbide-1 is replaced with modified silicon carbide-3 in equal amounts.

[0053] Example 6 A composite sheet based on electron beam curing and its preparation method are described. The specific implementation method is the same as in Example 1, except that modified silicon carbide-1 is replaced with modified silicon carbide-4 in equal amounts.

[0054] Example 7 A composite sheet based on electron beam curing and its preparation method are described. The specific implementation method is the same as in Example 1, except that modified silicon carbide-1 is replaced with modified silicon carbide-5 in equal amounts.

[0055] Comparative Example 1 An electron beam-cured composite sheet includes a PETG substrate and a coating attached thereto; the coating comprises the following raw materials in parts by weight: 60 parts polyurethane acrylate, 20 parts tripropylene glycol diacrylate, 4.5 parts trimethylolpropane triacrylate, 12 parts modified silicon carbide-1, 1.5 parts dispersant, and 1.5 parts leveling agent.

[0056] This embodiment is based on a method for preparing composite sheets using electron beam curing, which includes the following steps: S1. Add polyurethane acrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, dispersant, and leveling agent into the reactor and stir for 45 minutes to obtain a mixture. S2. Add modified silicon carbide-1 to the mixture obtained in step S1 and stir for 25 minutes to obtain the coating. S3. The PETG substrate is corona-treated to a dyne value of 32 to obtain a pretreated PETG substrate; S4. Apply the coating obtained in step S2 onto the pretreated PETG substrate, with a coating amount of 11 g / m². 2 The composite sheet is obtained by curing with an electron beam curing machine.

[0057] The parameters for curing using the electron beam curing machine are: accelerating voltage 160 keV, radiation dose 45 kGy, transmission line speed 30 m / min, and oxygen concentration 170 ppm.

[0058] Comparative Example 2 A composite sheet based on electron beam curing and its preparation method are described. The specific implementation method is the same as in Example 1, except that modified silicon carbide-1 is replaced with an equal amount of silicon carbide.

[0059] Performance testing The composite sheets obtained in the above embodiments and comparative examples were tested: Corrosion resistance: Salt spray resistance test was conducted according to ASTM B117 salt spray test, and adhesion test was conducted on the samples after the salt spray test according to ASTM D3359 Method B to characterize the corrosion resistance of the composite sheet.

[0060] Abrasion resistance: Mass loss (m) was tested according to ASTM-D4060 standard to characterize the abrasion resistance of the composite sheet.

[0061] Weather resistance and UV resistance: The color difference ΔE was used to characterize the UV resistance of the composite sheet by UVA-340 irradiation at 60℃ for 1000h accelerated aging test.

[0062] The test results are shown in Table 1: Table 1 As shown in Table 1, the composite sheets prepared in Examples 1-3 of this invention exhibit excellent wear resistance, salt spray resistance, and UV aging resistance, meaning they possess excellent wear resistance, corrosion resistance, and weather resistance. A comparison between Example 4 and Example 1 shows that changing the ratio of silicon carbide to lanthanum nitrate affects the formation of the lanthanum compound coating layer, thereby affecting the dispersibility of silicon carbide and leading to a deterioration in the wear resistance, corrosion resistance, and weather resistance of the composite sheets. A comparison between Example 5 and Example 1 shows that changing the ratio of the rare earth-silicon carbide composite to KH-570 silane coupling agent results in more double bond segments of the silane coupling agent participating in the polymerization reaction, which may interfere with the polymerization process of the main resin, leading to… The wear resistance, corrosion resistance, and weather resistance of the composite sheet decreased. A comparison between Example 6 and Example 1 shows that the wear resistance of the composite sheet decreased when a single, finer-sized silicon carbide particle was added. A comparison between Example 7 and Example 1 shows that the wear resistance, corrosion resistance, and weather resistance of the composite sheet decreased when unmodified silicon carbide was added. A comparison between Comparative Example 1 and Example 1 shows that the corrosion resistance of the composite sheet decreased when 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane was not added. A comparison between Comparative Example 2 and Example 1 shows that the wear resistance, corrosion resistance, and weather resistance of the composite sheet were poor when unmodified silicon carbide was directly added.

[0063] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A composite sheet based on electron beam curing, characterized in that, It includes a PETG substrate and a coating attached thereto; the coating comprises the following raw materials in parts by weight: 50-70 parts of polyurethane acrylate, 1-3 parts of bifunctional fluorinated acrylate monomer, 15-25 parts of bifunctional reactive diluent, 3-6 parts of trimethylolpropane triacrylate, 10-15 parts of modified silicon carbide, 1-2 parts of dispersant, and 1-2 parts of leveling agent.

2. The composite sheet based on electron beam curing according to claim 1, characterized in that, The bifunctional fluorinated acrylate monomer is 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane.

3. The composite sheet based on electron beam curing according to claim 1, characterized in that, The bifunctional reactive diluent is one or more of tripropylene glycol diacrylate, dipropylene glycol diacrylate, and 1,6-hexanediol diacrylate.

4. The composite sheet based on electron beam curing according to claim 1, characterized in that, The method for preparing the modified silicon carbide includes the following steps: A1. Add lanthanum nitrate to a 70-80 wt% aqueous ethanol solution and stir for 3-5 min. Add citric acid and ethylene glycol, stir at 60-70°C for 20-40 min, and adjust the pH to 1.5-2 to obtain a sol. A2. Add silicon carbide to the sol obtained in step A1, sonicate for 30-50 minutes, stir for 1-3 hours, evaporate by rotary evaporation, and dry to obtain powder; A3. The powder obtained in step A2 is heated to 700-800°C at a rate of 4-6°C / min and held for 1-1.5h. It is then cooled to room temperature in the furnace, ground, and sieved to obtain rare earth-silicon carbide composite. A4. The rare earth-silicon carbide composite obtained in step A3 is washed with 0.1-0.5 mol / L sodium hydroxide aqueous solution and then added to 78-90 wt% ethanol aqueous solution with a silane coupling agent containing double bonds. The mixture is stirred at 50-60°C for 1-2 h and then dried to obtain modified silicon carbide.

5. The composite sheet based on electron beam curing according to claim 4, characterized in that, The silicon carbide is a combination of silicon carbide with a particle size of 2-10 μm and silicon carbide with a particle size of 200-500 nm.

6. The composite sheet based on electron beam curing according to claim 4, characterized in that, The mass ratio of lanthanum nitrate to silicon carbide is 1:(5-10).

7. The composite sheet based on electron beam curing according to claim 4, characterized in that, The mass ratio of the rare earth-silicon carbide composite and the silane coupling agent containing double bonds in step A4 is 1:(0.015-0.025).

8. The composite sheet based on electron beam curing according to claim 4, characterized in that, The silane coupling agent containing double bonds is A-151 silane coupling agent and / or KH-570 silane coupling agent.

9. The composite sheet based on electron beam curing according to claim 1, characterized in that, The dispersant is a polycarboxylate dispersant.

10. A method for preparing a composite sheet based on electron beam curing as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Add polyurethane acrylate, bifunctional fluorinated acrylate monomer, bifunctional reactive diluent, trimethylolpropane triacrylate, dispersant, and leveling agent into a reaction vessel, stir at 25-35°C for 30-60 minutes to obtain a mixture. S2. Add the modified silicon carbide to the mixture obtained in step S1, stir at 25-35°C for 20-30 minutes to obtain the coating. S3. The PETG substrate is corona-treated to a dyne value of 30-34 to obtain a pretreated PETG substrate; S4. Apply the coating obtained in step S2 onto the pretreated PETG substrate, with a coating amount of 10-12 g / m². 2 The composite sheet is obtained by curing with an electron beam curing machine.

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