Composite film for SPC wood board and preparation method of composite film

Abstract

The invention discloses a composite film for an SPC wood board and a preparation method of the composite film, and relates to the technical field of composite films. The composite film for the SPC wood board comprises the following raw materials in parts by weight: 40-50 parts of polyvinyl chloride, 20-30 parts of polyurethane, 10-15 parts of epoxy resin, 3-5 parts of nano silicon dioxide, 2-4 parts of an anti-ultraviolet agent, 5-8 parts of modified polyvinyl alcohol, 5-10 parts of modified polyacrylate, 0.5-1 part of an antibacterial agent, 3-5 parts of a plasticizer, 0.5-2 parts of an antioxidant and 0.5-2 parts of a lubricant. The composite film for the SPC wood board has remarkable advantages and excellent protection performance, the wear resistance is enhanced by the nano material, and scratch wear is reduced; the anti-ultraviolet agent and the special formula can effectively resist ultraviolet rays and moisture and prevent aging, color fading, deformation and mildewing; the antibacterial and antioxidant functions are achieved, the health of the use environment is guaranteed, and the service life of the composite film is prolonged; and the plasticizer and the lubricant improve the fluidity, the process is simple, large-scale production is facilitated, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of composite films, and particularly to a composite film for SPC wood boards and a preparation method thereof. Background Art

[0002] In the field of building decoration materials, SPC wood boards have been widely used in indoor and outdoor decoration in recent years due to their excellent waterproof performance, good wear resistance, and convenient installation method. However, with the continuous improvement of market demand and the increasing diversification of application scenarios, many problems have emerged in the actual use of SPC wood boards, which have restricted their further promotion and application.

[0003] The surface protection performance of SPC wood boards needs to be strengthened urgently. In daily use, the surface of SPC wood boards is extremely vulnerable to various external forces, such as the dragging of furniture and the friction of shoe soles, which will cause scratches and wear on the surface of the wood boards. This not only seriously affects the aesthetics of SPC wood boards, making them unable to maintain a long-term decorative effect, but also reduces the service life of the wood boards and increases the maintenance and replacement costs.

[0004] The weather resistance of SPC wood boards is insufficient. Under the long-term irradiation of ultraviolet rays, SPC wood boards are prone to aging, the color gradually fades and becomes lighter, losing their original color and texture. In a humid environment, the wood boards may also deform and mildew, greatly affecting their structural stability and use safety.

[0005] There are many defects in the existing composite film technology for SPC wood boards. Some composite films perform poorly in the combination with SPC wood boards, the adhesion is not strong enough, and the composite film is prone to peeling off after being used for a period of time, unable to play a continuous and effective protective role for the wood boards. Some composite films have shortcomings in antibacterial performance and are difficult to inhibit the growth of microorganisms such as bacteria and molds. In some places with high hygiene requirements, such as hospitals, schools, food processing workshops, etc., they cannot meet the actual needs. In addition, the existing composite films are also unsatisfactory in terms of antioxidant performance. During long-term use, they are easily affected by factors such as oxygen and moisture in the air, resulting in a decline in the performance of the composite film itself, and then affecting the protection effect on SPC wood boards. Moreover, the preparation process of some composite films is complex, involving multiple cumbersome processes and high-precision operation requirements, which not only increases the production difficulty but also makes the production cost remain high, not conducive to large-scale industrial production and market promotion.

[0006] In summary, developing a composite film for SPC wood boards and a preparation method thereof that can effectively solve the above problems, have excellent protective performance, good weather resistance, strong antibacterial and antioxidant capabilities, and a simple preparation process and reasonable cost has become a research hotspot and urgent need in this field. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a composite film for SPC wood boards and a preparation method thereof, which solves the problems such as poor wear resistance.

[0008] To achieve the above objectives, the present invention is realized through the following technical solutions:

[0009] A composite film for SPC wood boards, comprising the following raw materials in parts by weight: 40-50 parts of polyvinyl chloride, 20-30 parts of polyurethane, 10-15 parts of epoxy resin, 3-5 parts of nano-silica, 2-4 parts of ultraviolet absorber, 5-8 parts of modified polyvinyl alcohol, 5-10 parts of modified polyacrylate, 0.5-1 part of antibacterial agent, 3-5 parts of plasticizer, 0.5-2 parts of antioxidant, and 0.5-2 parts of lubricant.

[0010] Further, the specific preparation steps of the modified polyvinyl alcohol are as follows:

[0011] A1. Add the weighed deionized water into a three-necked flask, turn on the magnetic stirrer, set the stirring speed to 300 r / min, slowly add polyvinyl chloride, and at the same time turn on the heating device, gradually increase the temperature to 80 °C, and continuously stir until completely dissolved to form a uniform and transparent solution; slowly add ammonium persulfate to the polyvinyl chloride solution and continue stirring for 5 minutes, then add acrylic acid and nano-zinc oxide, and adjust the temperature to 70 °C and react for 2 hours; the dosage ratio of polyvinyl chloride, deionized water, acrylic acid, nano-zinc oxide, and ammonium persulfate is 10 g: 90 g: 3 g: 1 g: 1 g;

[0012] A2. After the above reaction is completed, turn off the heating device. When the temperature drops to 60 °C, slowly add adipic dihydrazide, and at the same time adjust the rotation speed to 200 r / min and stir for 1 hour; slowly add polyaniline, nano-graphene, and carbon nanotubes into the three-necked flask in sequence, and continue to stir at 200 r / min for 30 minutes; the dosage ratio of adipic dihydrazide, polyaniline, nano-graphene is 2 g: 1 g: 3 g: 0.5 g;

[0013] A3. Slowly add nano-titanium dioxide, silane coupling agent KH-550, and chitosan into the modified polyvinyl alcohol solution in sequence, adjust the reaction temperature to 50 °C, and continue to react at a stirring speed of 200 r / min for 1 hour; after the reaction is completed, slowly pour the modified polyvinyl alcohol solution in the three-necked flask into a clean, flat, and treated glass mold, and use the casting method to evenly spread the solution on the surface of the mold to form a uniform thin film; put the glass mold with the modified polyvinyl alcohol solution into an oven preheated to 80 °C and dry for 2 hours. After drying, carefully take out the glass mold. After it cools to room temperature, gently peel off the modified polyvinyl alcohol film from the mold to obtain the final product; the dosage ratio of nano-titanium dioxide, silane coupling agent, and chitosan is 2 g: 1 g: 1 g.

[0014] In step A1, ammonium persulfate decomposes when heated, the peroxy bond breaks, and sulfate radicals are generated. The sulfate radicals initiate the breaking of the C=C double bond of acrylic acid to form acrylic acid radicals. The acrylic acid radicals undergo a hydrogen abstraction reaction with the hydrogen atoms on the polyvinyl chloride molecular chain, forming new radical sites on the polyvinyl chloride molecular chain. Subsequently, the acrylic acid radicals combine with these sites to undergo a radical polymerization reaction, introducing carboxyl groups onto the polyvinyl chloride molecular chain and increasing the reaction activity of polyvinyl chloride. In step A2, adipic dihydrazide acts as a crosslinking agent. The hydrazide groups in its molecules undergo a dehydration condensation reaction with the carboxyl groups on the polyvinyl chloride molecular chain at 60°C. The C-O bond in the carboxyl group and the N-H bond in the hydrazide group break, forming new C-N bonds, achieving the crosslinking of the polyvinyl chloride molecular chain and constructing a network structure to enhance the material stability. In step A3, the silane coupling agent hydrolyzes, the Si-O bond in the silane oxy group breaks, and reacts with water to form silanol groups. The silanol groups undergo a condensation reaction with the hydroxyl groups on the surface of nano-titanium dioxide to form Si-O-Ti bonds, enabling the better dispersion of nano-titanium dioxide in the system.

[0015] Furthermore, the modified polyacrylate is specifically prepared as follows:

[0016] B1. Slowly add methyl methacrylate, butyl acrylate, and acrylic acid into a clean and dry reaction kettle in sequence, turn on the stirring device, and stir at a speed of 200 r / min; then add 2-hydroxyethyl methacrylate phosphate and benzoyl peroxide, continue stirring for 10 minutes, and then add styrene and continue stirring for 15 minutes; introduce nitrogen into the reaction kettle for 15 minutes to exhaust the air in the reaction kettle, close the nitrogen valve, turn on the heating device, slowly raise the temperature in the reaction kettle to 80°C, and maintain the temperature for reaction for 4 hours to obtain a phosphorus-containing copolymer; the dosage ratio of methyl methacrylate, butyl acrylate, and acrylic acid is 50 g: 30 g: 20 g; the dosage ratio of 2-hydroxyethyl methacrylate phosphate, benzoyl peroxide, and styrene is 2 g: 0.5 g: 1 g;

[0017] B2. After the above reaction is completed, add nano-zinc oxide and nano-aluminum hydroxide into the copolymer solution in the reaction kettle in sequence, continue stirring at a speed of 200 r / min for 5 minutes, then add graphene, continue stirring for 10 minutes, and then slowly add the silane coupling agent and stir for reaction for 1 hour; the dosage ratio of nano-zinc oxide, nano-aluminum hydroxide, graphene, and the silane coupling agent is 3 g: 2 g: 0.5 g: 1 g;

[0018] B3. Add nano-silica and epoxy group silane to the modified polyacrylate solution in the reaction kettle in sequence. At the same time, adjust the reaction temperature to 70 °C and keep this temperature constant. After stirring at a stirring speed of 200 r / min for 5 minutes, add carbon nanotubes, and then continue to stir at a stirring speed of 200 r / min for 1 hour. After the reaction ends, slowly pour the modified polyacrylate solution in the reaction kettle into a clean, flat and treated glass mold, and use the solution casting method to evenly spread the solution on the surface of the mold to form a uniform thin film. Put the glass mold with the modified polyacrylate solution into an oven preheated to 100 °C and dry for 1 hour. After drying, carefully take out the glass mold. After it cools to room temperature, gently peel off the modified polyacrylate film from the mold to obtain the final product. The dosage ratio of nano-silica, epoxy group silane and carbon nanotubes is 2 g: 1 g: 0.3 g.

[0019] In step B1, benzoyl peroxide decomposes when heated, the O-O bond breaks, and benzoyl radicals are generated. The benzoyl radicals initiate the breaking of the carbon-carbon double bonds in methyl methacrylate, butyl acrylate, acrylic acid and 2-hydroxyethyl methacrylate phosphate, and a free radical copolymerization reaction occurs to form a phosphorus-containing copolymer. During the reaction process, the double bonds break, new C-C bonds are formed to connect each monomer, and phosphorus-containing groups are introduced, laying a foundation for subsequent reactions and the improvement of material properties. In step B2, nano-zinc oxide and nano-aluminum hydroxide are added to the phosphorus-containing copolymer. Groups such as carboxyl groups in the phosphorus-containing copolymer may coordinate with zinc atoms on the surface of nano-zinc oxide and undergo condensation reactions with hydroxyl groups on the surface of nano-aluminum hydroxide, enhancing properties such as the flame retardancy of the material. After adding the silane coupling agent, the silanol groups generated by its hydrolysis condense with the hydroxyl groups on the surfaces of nano-zinc oxide and nano-aluminum hydroxide to form Si-O-Zn and Si-O-Al bonds. At the same time, the organic functional groups at the other end react with the molecular chains of the phosphorus-containing copolymer, improving the dispersibility and interfacial compatibility of the nano-materials. In step B3, the epoxy group silane hydrolyzes, the Si-O bond breaks to generate silanol groups, and the silanol groups condense with the hydroxyl groups on the surface of nano-silica to form Si-O-Si bonds, making the nano-silica evenly dispersed. The epoxy groups of the epoxy group silane react with the carboxyl groups and hydroxyl groups on the polyacrylate molecular chains, the epoxy bonds open, and new chemical bonds are formed to connect the nano-silica and the polyacrylate molecular chains, improving the material properties.

[0020] Further, the epoxy resin is bisphenol A epoxy resin.

[0021] Further, the ultraviolet light absorber is one of nano-zinc oxide, nano-titanium dioxide and nano-aluminum oxide.

[0022] Further, the antibacterial agent is one of dodecyl dimethyl benzyl ammonium chloride, cetyl trimethyl ammonium bromide and tributyltin compounds.

[0023] Further, the plasticizer is one of dioctyl phthalate, dibutyl phthalate, and epoxidized soybean oil.

[0024] Further, the antioxidant is one of antioxidant 1010 and antioxidant 168.

[0025] Further, the lubricant is one of stearic acid, polyethylene wax, and oleic amide.

[0026] A method for preparing a composite film for SPC wood boards specifically comprises the following steps:

[0027] Weigh each raw material by weight. First, add polyvinyl chloride, polyurethane, and epoxy resin into a high-speed mixer and stir at 400 r / min for 10 minutes. Then, sequentially add nano-silica and ultraviolet absorber, and continue stirring for 15 minutes. Next, add antibacterial agent, plasticizer, antioxidant, and lubricant, and stir for 20 minutes. Then, add modified polyvinyl alcohol film and modified polyacrylate film, and stir at high speed for 30 minutes to make each component reach a uniform dispersion state. Add the mixed material into a twin-screw extruder, set the temperature of the extruder from the feeding section to the head to be 150 °C, 160 °C, and 170 °C, and the screw speed to be 250 r / min, and perform melt extrusion to obtain a uniform composite film melt, ensuring that the material is fully plasticized during the extrusion process. Press the melt into a film with a thickness of 1.0 mm through a calender, control the calendering temperature at 150 °C, and the calendering pressure at 15 MPa. Perform surface corona treatment on the calendered film, cool the treated film to room temperature through a cooling roller, and finally wind it up to obtain the finished composite film.

[0028] The present invention provides a composite film for SPC wood boards and a preparation method thereof, having the following beneficial effects:

[0029] 1. Through the synergistic effect of a variety of carefully selected functional raw materials, the composite film of the present invention significantly improves the protection ability for SPC wood boards. Among them, nano-silica and nano-aluminum oxide have high hardness and good wear resistance, and are uniformly dispersed in the composite film to form a strong protection barrier, which can effectively resist external mechanical damages such as friction and scratching, greatly reducing the possibility of scratches and wear on the surface of SPC wood boards, enabling it to still maintain good appearance and performance during long-term use, and greatly extending the service life of SPC wood boards. At the same time, the addition of polytetrafluoroethylene endows the composite film with the characteristic of low friction coefficient, further reducing the friction force between the external object and the surface of the SPC wood board and reducing the generation of wear.

[0030] 2. Regarding the problem that SPC wood boards are vulnerable to ultraviolet rays and humid environments, the present invention adds highly efficient ultraviolet absorbers, such as nano-zinc oxide, nano-titanium dioxide, or nano-aluminum oxide, etc., to the composite film. These ultraviolet absorbers can effectively absorb and reflect ultraviolet rays, preventing the direct irradiation of ultraviolet rays on the SPC wood board, thereby significantly slowing down the aging and fading speed of the wood board. The other components in the composite film cooperate with each other to endow it with good waterproof and moisture-proof properties, which can effectively block the intrusion of moisture and avoid problems such as deformation and mildew of the SPC wood board in a humid environment, ensuring the structural stability and use safety of the wood board under various complex climatic conditions.

[0031] 3. The antibacterial agents added to the composite film, such as dodecyl dimethyl benzyl ammonium chloride, cetyl trimethyl ammonium bromide, or tributyltin compounds, etc., can effectively inhibit the growth and reproduction of microorganisms such as bacteria and molds, keep the surface of the SPC wood board clean and hygienic, and provide a healthy environment for users. Especially in some places with extremely high hygiene requirements, such as hospital wards, operating rooms, school canteens, dormitories, and food processing workshops, etc., the composite film of the present invention can play an important role. The addition of antioxidants effectively improves the antioxidant ability of the composite film itself, preventing its performance from declining due to oxidation by factors such as oxygen and moisture in the air during long-term use, and ensuring the long-term stable protection of the composite film for the SPC wood board.

[0032] 4. The present invention adds plasticizers and lubricants, such as dioctyl phthalate, dibutyl phthalate, epoxy soybean oil, and stearic acid, polyethylene wax, oleic amide, etc., to the formulation design of the composite film. These components significantly improve the fluidity of the materials during the preparation process of the composite film, enabling the materials to be more evenly mixed and dispersed during processing, reducing the processing difficulty and energy consumption. Moreover, the preparation method of the composite film of the present invention has a simple process, convenient operation, does not require complex equipment and high-precision operation, and is easy to realize large-scale industrial production. This not only improves production efficiency but also reduces production costs, making the product more competitive in the market and providing strong support for the wide application of SPC wood boards. Detailed implementation mode

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0034] Example 1, preparing modified polyvinyl alcohol, the specific steps are as follows:

[0035] A1. Add 90 g of deionized water weighed well into a three-necked flask, turn on the magnetic stirrer, set the stirring speed to 300 r / min, slowly add 10 g of polyvinyl chloride, and at the same time turn on the heating device, gradually increase the temperature to 80 °C, and continue stirring until completely dissolved to form a uniform and transparent solution; slowly add 1 g of ammonium persulfate to the polyvinyl chloride solution and continue stirring for 5 minutes, then add 3 g of acrylic acid and 1 g of nano-zinc oxide, adjust the temperature to 70 °C, and react for 2 hours;

[0036] A2. After the above reaction ends, turn off the heating device. When the temperature drops to 60 °C, slowly add 2 g of adipic dihydrazide, and at the same time adjust the rotation speed to 200 r / min and stir for 1 hour; slowly add 1 g of polyaniline, 3 g of nano-graphene and 0.5 g of carbon nanotubes into the three-necked flask in sequence, and continue stirring at 200 r / min for 30 minutes;

[0037] A3. Slowly add 2 g of nano-titanium dioxide, 1 g of silane coupling agent KH-550 and 1 g of chitosan into the modified polyvinyl alcohol solution in sequence, adjust the reaction temperature to 50 °C, and continue reacting at a stirring speed of 200 r / min for 1 hour; after the reaction ends, slowly pour the modified polyvinyl alcohol solution in the three-necked flask into a clean, flat and treated glass mold, and use the casting method to evenly spread the solution on the surface of the mold to form a uniform thin film; put the glass mold with the modified polyvinyl alcohol solution into an oven preheated to 80 °C and dry for 2 hours. After drying, carefully take out the glass mold. After it cools to room temperature, gently peel off the modified polyvinyl alcohol film from the mold to obtain the final product.

[0038] Example 2. Preparation of modified polyacrylate, the specific steps are as follows:

[0039] B1. Slowly add 50 g of methyl methacrylate, 30 g of butyl acrylate and 20 g of acrylic acid into a clean and dry reaction kettle in sequence, turn on the stirring device, and stir at a speed of 200 r / min; then add 2 g of 2-hydroxyethyl methacrylate phosphate and 0.5 g of benzoyl peroxide, continue stirring for 10 minutes, then add 1 g of styrene, and continue stirring for 15 minutes; introduce nitrogen into the reaction kettle for 15 minutes to exhaust the air in the reaction kettle, close the nitrogen valve, turn on the heating device, slowly increase the temperature in the reaction kettle to 80 °C, and keep the temperature for reaction for 4 hours to obtain a phosphorus-containing copolymer;

[0040] B2. After the above reaction ends, add 3 g of nano-zinc oxide and 2 g of nano-aluminum hydroxide into the copolymer solution in the reaction kettle in sequence, continue stirring at a speed of 200 r / min for 5 minutes, then add 0.5 g of graphene, continue stirring for 10 minutes, and then slowly add 1 g of silane coupling agent and stir for reaction for 1 hour;

[0041] B3. Add 2 g of nano-silica and 1 g of epoxy group silane to the modified polyacrylate solution in the reaction kettle in sequence. At the same time, adjust the reaction temperature to 70 °C and keep this temperature constant. After stirring at a stirring speed of 200 r / min for 5 minutes, add 0.3 g of carbon nanotubes, and then continue to stir at a stirring speed of 200 r / min for 1 hour. After the reaction ends, slowly pour the modified polyacrylate solution in the reaction kettle into a clean, flat and treated glass mold, and use the solution casting method to evenly spread the solution on the surface of the mold to form a uniform thin film. Place the glass mold with the modified polyacrylate solution in an oven preheated to 100 °C and dry for 1 hour. After drying, carefully take out the glass mold. After it cools to room temperature, gently peel off the modified polyacrylate film from the mold to obtain the final product.

[0042] Example 3. To prepare the composite film for SPC wood board, the specific steps are as follows:

[0043] Weigh each raw material by weight. First, add 40 parts of polyvinyl chloride, 20 parts of polyurethane, and 10 parts of epoxy resin to a high-speed mixer and stir at 400 r / min for 10 minutes. Then, add 3 parts of nano-silica and 2 parts of nano-zinc oxide in sequence and continue to stir for 15 minutes. Next, add 0.5 part of dodecyl dimethyl benzyl ammonium chloride, 3 parts of dioctyl phthalate, 0.5 part of antioxidant 1010, and 0.5 part of stearic acid and stir for 20 minutes. Then add 5 parts of the modified polyvinyl alcohol film prepared in Example 1 and 5 parts of the modified polyacrylate film prepared in Example 2 and stir at high speed for 30 minutes to make each component reach a uniform dispersion state. Add the mixed material into a twin-screw extruder, set the temperature of the extruder from the feeding section to the head to be 150 °C, 160 °C, 170 °C, and the screw speed to be 250 r / min, and carry out melt extrusion to obtain a uniform composite film melt, ensuring that the material is fully plasticized during the extrusion process. Roll the melt into a film with a thickness of 1.0 mm through a calender, control the calendering temperature at 150 °C, and the calendering pressure at 15 MPa. Carry out surface corona treatment on the calendered film, cool the treated film to room temperature through a cooling roller, and finally wind it up to obtain the finished composite film.

[0044] Example 4. To prepare the composite film for SPC wood board, the specific steps are as follows:

[0045] Weigh each raw material by weight parts. First, add 50 parts of polyvinyl chloride, 30 parts of polyurethane, and 15 parts of epoxy resin into a high-speed mixer, and stir for 10 minutes at 400 r / min. Then, add 5 parts of nano-silica and 4 parts of nano-titanium dioxide in sequence, and continue to stir for 15 minutes. Next, add 1 part of cetyltrimethylammonium bromide, 5 parts of dibutyl phthalate, 2 parts of antioxidant 168, and 2 parts of polyethylene wax, and stir for 20 minutes. Then, add 8 parts of the modified polyvinyl alcohol film prepared in Example 1 and 10 parts of the modified polyacrylate film prepared in Example 2, and stir at high speed for 30 minutes to make each component reach a uniform dispersion state. Add the mixed material into a twin-screw extruder, set the temperature of the extruder from the feeding section to the head to be 150 °C, 160 °C, and 170 °C, and the screw speed to be 250 r / min, and carry out melt extrusion to obtain a uniform composite film melt, ensuring that the material is fully plasticized during the extrusion process. Press the melt into a film with a thickness of 1.0 mm through a calender, control the calendering temperature at 150 °C, and the calendering pressure at 15 MPa. Carry out surface corona treatment on the calendered film, cool the treated film to room temperature through a cooling roll, and finally wind it up to obtain the finished composite film.

[0046] Example 5. The specific steps for preparing the composite film for SPC wood board are as follows:

[0047] Weigh each raw material by weight parts. First, add 45 parts of polyvinyl chloride, 25 parts of polyurethane, and 12 parts of epoxy resin into a high-speed mixer, and stir for 10 minutes at 400 r / min. Then, add 4 parts of nano-silica and 3 parts of nano-aluminum oxide in sequence, and continue to stir for 15 minutes. Next, add 0.7 part of tributyltin compound, 4 parts of epoxidized soybean oil, 1 part of antioxidant 168, and 1 part of oleic acid amide, and stir for 20 minutes. Then, add 6 parts of the modified polyvinyl alcohol film prepared in Example 1 and 7 parts of the modified polyacrylate film prepared in Example 2, and stir at high speed for 30 minutes to make each component reach a uniform dispersion state. Add the mixed material into a twin-screw extruder, set the temperature of the extruder from the feeding section to the head to be 150 °C, 160 °C, and 170 °C, and the screw speed to be 250 r / min, and carry out melt extrusion to obtain a uniform composite film melt, ensuring that the material is fully plasticized during the extrusion process. Press the melt into a film with a thickness of 1.0 mm through a calender, control the calendering temperature at 150 °C, and the calendering pressure at 15 MPa. Carry out surface corona treatment on the calendered film, cool the treated film to room temperature through a cooling roll, and finally wind it up to obtain the finished composite film.

[0048] Comparative Example 1

[0049] Keep the other steps unchanged, and only replace the modified polyvinyl alcohol in Example 4 with polyvinyl alcohol without any treatment to prepare a composite film.

[0050] Comparative Example 2

[0051] The remaining steps remain unchanged. Only replace the modified polyacrylate in Example 4 with polyacrylate without any treatment to prepare the composite film.

[0052] Performance test

[0053]

[0054]

[0055] The composite film for SPC wood boards of the present invention is significantly superior to the comparative examples in terms of performance. The composite films of Examples 3 - 5 are excellent in terms of tensile strength, elongation at break, wear resistance, antibacterial rate, and anti-ultraviolet performance. Compared with Comparative Examples 1 and 2 that do not use modified polyvinyl alcohol and modified polyacrylate, the present invention greatly improves the comprehensive performance of the composite film by optimizing the raw material formula and preparation process, effectively solves many problems in the practical application of SPC wood boards, and has good application prospects.

[0056] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution. As long as they do not deviate from the invention or exceed the scope defined by this claim book, they should fall within the protection scope of the present invention.

Claims

1. A composite film for SPC wood board according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 40-50 parts of polyvinyl chloride, 20-30 parts of polyurethane, 10-15 parts of epoxy resin, 3-5 parts of nano silicon dioxide, 2-4 parts of anti-ultraviolet agent, 5-8 parts of modified polyvinyl alcohol, 5-10 parts of modified polyacrylate, 0.5-1 part of antibacterial agent, 3-5 parts of plasticizer, 0.5-2 parts of antioxidant and 0.5-2 parts of lubricant.

2. The composite film for SPC wood board according to claim 1, characterized in that: The modified polyvinyl alcohol is specifically prepared in the following steps: A1. Add the weighed deionized water into a three-necked flask, turn on the magnetic stirrer, set the stirring speed to 300r / min, slowly add polyvinyl chloride, turn on the heating device at the same time, gradually increase the temperature to 80℃, continue stirring until it is completely dissolved to form a uniform and transparent solution; slowly add ammonium persulfate to the polyvinyl chloride solution and continue stirring for 5 minutes, then add acrylic acid and nano zinc oxide, adjust the temperature to 70℃, and react for 2 hours; the dosage ratio of polyvinyl chloride, deionized water, ammonium persulfate, acrylic acid, and nano zinc oxide is 10g:90g:1g:3g:1g; A2. After the above reaction is completed, turn off the heating device, wait until the temperature drops to 60°C, slowly add adipic acid dihydrazide, and adjust the speed to 200r / min and stir for 1 hour; slowly add polyaniline, nanographene and carbon nanotubes into the three-necked flask in turn, and continue to stir at 200r / min for 30 minutes; the amount ratio of adipic acid dihydrazide, polyaniline and nanographene is 2g:1g:3g:0.5g; A3. Slowly add nano-titanium dioxide, silane coupling agent KH-550 and chitosan to the modified polyvinyl alcohol solution in sequence, adjust the reaction temperature to 50°C, and continue to react at a stirring speed of 200r / min for 1 hour; after the reaction, slowly pour the modified polyvinyl alcohol solution in the three-necked flask into a clean, flat and treated glass mold, and use the casting method to evenly spread the solution on the surface of the mold to form a uniform film; put the glass mold covered with the modified polyvinyl alcohol solution into an oven pre-heated to 80°C and dry it for 2 hours. After drying, carefully take out the glass mold, wait for it to cool to room temperature, and gently peel off the modified polyvinyl alcohol film from the mold to obtain the final product; the dosage ratio of nano-titanium dioxide, silane coupling agent and chitosan is 2g:1g:1g.

3. The composite film for SPC wood board according to claim 1, characterized in that: The modified polyacrylate is specifically prepared in the following steps: B1. Slowly add methyl methacrylate, butyl acrylate and acrylic acid to a clean and dry reactor in sequence, turn on the stirring device, and stir at a speed of 200r / min; then add hydroxyethyl methacrylate phosphate and benzoyl peroxide, continue stirring for 10 minutes, then add styrene, and continue stirring for 15 minutes; introduce nitrogen into the reactor for 15 minutes to exhaust the air in the reactor, close the nitrogen valve, turn on the heating device, slowly increase the temperature in the reactor to 80°C, and maintain the temperature for 4 hours to obtain a phosphorus-containing copolymer; the amount ratio of methyl methacrylate, butyl acrylate and acrylic acid is 50g:30g:20g; the amount ratio of hydroxyethyl methacrylate phosphate, benzoyl peroxide and styrene is 2g:0.5g:1g; B2. After the above reaction is completed, nano zinc oxide and nano aluminum hydroxide are added to the copolymer solution in the reactor in sequence, and the stirring is continued at a stirring speed of 200 r / min for 5 minutes, and then graphene is added, and the stirring is continued for 10 minutes, and then the silane coupling agent is slowly added, and the stirring reaction is carried out for 1 hour; the amount ratio of nano zinc oxide, nano aluminum hydroxide, graphene, and silane coupling agent is 3g:2g:0.5g:1g; B3. Add nano-silica and epoxy silane to the modified polyacrylate solution in the reactor in sequence, adjust the reaction temperature to 70°C, and keep the temperature constant. After stirring at a stirring speed of 200 r / min for 5 minutes, add carbon nanotubes, and then continue to stir at a stirring speed of 200 r / min for 1 hour. After the reaction is completed, slowly pour the modified polyacrylate solution in the reactor into a clean, flat and treated glass mold, and use a solution casting method to evenly spread the solution on the surface of the mold to form a uniform film. Put the glass mold covered with the modified polyacrylate solution into an oven pre-heated to 100°C and dry it for 1 hour. After drying, carefully take out the glass mold, wait for it to cool to room temperature, and gently peel off the modified polyacrylate film from the mold to obtain the final product. The dosage ratio of nano-silica, epoxy silane and carbon nanotubes is 2g:1g:0.3g.

4. The composite film for SPC wood board according to claim 1, characterized in that: The epoxy resin is bisphenol A type epoxy resin.

5. The composite film for SPC wood board according to claim 1, characterized in that: The anti-ultraviolet agent is one of nano zinc oxide, nano titanium dioxide and nano aluminum oxide.

6. The composite film for SPC wood board according to claim 1, characterized in that: The antibacterial agent is one of dodecyl dimethyl benzyl ammonium chloride, hexadecyl trimethyl ammonium bromide and tributyl tin compounds.

7. The composite film for SPC wood board according to claim 1, characterized in that: The plasticizer is one of dioctyl phthalate, dibutyl phthalate and epoxidized soybean oil.

8. The composite film for SPC wood board according to claim 1, characterized in that: The antioxidant is one of antioxidant 1010 and antioxidant 168.

9. The composite film for SPC wood board according to claim 1, characterized in that: The lubricant is one of stearic acid, polyethylene wax and oleic acid amide.

10. The method for preparing a composite film for SPC wood board according to claim 1, characterized in that: The specific steps include: Weigh various raw materials by weight, mix modified polyvinyl alcohol film, modified polyacrylate film, polyvinyl chloride, polyurethane, epoxy resin, nano-silicon dioxide, anti-ultraviolet agent, antibacterial agent, plasticizer, antioxidant and lubricant, add them into a high-speed mixer and stir them thoroughly; add the mixed materials into a twin-screw extruder, melt-extrude to obtain a uniform composite film melt; calender the melt into a film through a calender, perform surface corona treatment on the calendered film, cool the treated film to room temperature through a cooling roller, and finally roll it up to obtain a finished composite film.

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