High-performance composite coating for OSB (oriented strand board) as well as preparation method and application of high-performance composite coating

Abstract

The invention discloses a high-performance composite coating for an OSB board. Comprising the following raw materials in parts by weight: 35-45 parts of a core-shell fluorocarbon-acrylate composite emulsion, 12-15 parts of a waterborne epoxy acrylate emulsion, 5-8 parts of a waterborne polyurethane dispersion, 10-12 parts of modified expanded graphite, 3-5 parts of aluminum hypophosphite, 2-4 parts of modified potassium titanate whiskers and 1-3 parts of a carbon nanotube dispersion. The water-based paint is prepared from the following components in parts by weight: 6-8 parts of rutile type nano titanium dioxide / montmorillonite composite material, 4-6 parts of water-based coalescing agent, 2-3 parts of environment-friendly coupling agent, 0.5-1.0 part of water-based defoaming agent, 0.3-0.8 part of water-based flatting agent and 8-15 parts of deionized water. The invention further provides a preparation method of the high-performance composite coating for the OSB board. Through the collaborative design of an innovative composite film forming system and a multi-dimensional functional filler, the weather resistance, flame retardance, antibacterial property, adhesive force and mechanical property of the coating are comprehensively improved.

Description

Technical Field

[0001] This invention relates to the field of composite coating technology, specifically to a high-performance composite coating for OSB sheets, its preparation method, and its application. Background Technology

[0002] Oriented strand board (OSB) is widely used in construction, furniture, and packaging due to its excellent mechanical properties, cost-effectiveness, and high raw material utilization. However, the inherent defects of OSB, such as poor weather resistance, easy moisture absorption and deformation, and insufficient flame retardancy, severely limit its application in outdoor, humid, and fire-resistant environments. Applying functional coatings to the surface is the main way to solve these problems.

[0003] Currently, most commercially available OSB (Organic Sealing Board) sheet coatings use single film-forming substances such as water-based polyurethane, acrylate, or phenolic resin, combined with flame retardants and fillers. These coatings generally suffer from the following problems: First, performance is difficult to balance; for example, acrylic coatings have good weather resistance but poor flame retardancy, while phenolic coatings have excellent flame retardancy but are prone to aging and cracking. Second, environmental friendliness is poor; some products contain harmful substances such as formaldehyde and heavy metals. Third, adhesion to the porous OSB substrate is insufficient, making them susceptible to peeling due to humid and hot environments. Fourth, water resistance and corrosion resistance are limited, failing to effectively protect the substrate. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a high-performance composite coating for OSB sheets and its preparation method. Through the innovative synergistic design of the composite film-forming system and multi-dimensional functional fillers, the coating's weather resistance, flame retardancy, antibacterial properties, adhesion, and mechanical properties are comprehensively improved.

[0005] The present invention provides a high-performance composite coating for OSB boards, comprising the following components in parts by weight:

[0006] 35-45 parts of core-shell fluorocarbon-acrylate composite emulsion

[0007] 12-15 parts of waterborne epoxy acrylate emulsion

[0008] 5-8 parts of waterborne polyurethane dispersion

[0009] 10-12 parts of modified expanded graphite

[0010] 3-5 parts aluminum hypophosphite

[0011] 2-4 parts of modified potassium titanate whiskers

[0012] 1-3 parts of carbon nanotube dispersion

[0013] 6-8 parts of rutile nano-titanium dioxide / montmorillonite composite material

[0014] 4-6 parts of water-based film-forming aid

[0015] 2-3 parts of environmentally friendly coupling agent

[0016] 0.5-1.0 parts of water-based defoamer

[0017] 0.3-0.8 parts of water-based leveling agent

[0018] 8-15 parts deionized water.

[0019] Preferably, the core-shell fluorocarbon-acrylate composite emulsion is prepared by a semi-continuous seed emulsion polymerization method using hexafluorobutyl methacrylate and isooctyl acrylate as shell monomers, methyl methacrylate and acrylonitrile as core monomers, and a reactive emulsifier; the weight ratio of core monomers to shell monomers is 10:7; the reactive emulsifier is allyloxynonylphenol polyoxyethylene ether ammonium sulfate, used at 0.8-1.2% of the total weight of monomers; the initiator is ammonium persulfate, used at 1% of the total weight of monomers; the reaction temperature is 75-85℃; and the reaction time is 4-6 hours.

[0020] Preferably, the modified expanded graphite is prepared by adding expanded graphite to a 3-5 wt% ethanol solution of silane coupling agent KH-560, ultrasonically dispersing for 30-40 min, drying at 80-90℃ for 2-3 h, and grinding through a 200-mesh sieve; the weight ratio of expanded graphite to silane coupling agent KH-560 is 10:1.2.

[0021] Preferably, the preparation method of the rutile nano-titanium dioxide / montmorillonite composite material is as follows: montmorillonite is added to deionized water and ultrasonically dispersed for 20-30 min; rutile nano-titanium dioxide and 1-5% by weight of silver nitrate are added, the pH is adjusted to 3.5-4.5 with dilute nitric acid, and the reaction is carried out at 60-70℃ for 2-3 h. After filtration, washing, drying, and grinding through a 300-mesh sieve, the weight ratio of rutile nano-titanium dioxide to montmorillonite is 1:3.

[0022] Preferably, the aqueous film-forming aid is a mixture of dipropylene glycol methyl ether acetate and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a weight ratio of 1:(1.2-1.5).

[0023] Preferably, the environmentally friendly coupling agent is silane coupling agent KH-550.

[0024] Preferably, the carbon nanotube dispersion is an aqueous dispersion with a solid content of 5 wt%.

[0025] Preferably, the modified potassium titanate whiskers are prepared by adding potassium titanate whiskers to a 2-4 wt% ethanol solution of silane coupling agent KH-570, ultrasonically dispersing for 25-35 min, drying at 90-100℃ for 1.5-2.5 h, and grinding through a 300-mesh sieve; the weight ratio of potassium titanate whiskers to silane coupling agent KH-570 is 10:(0.8-1.2).

[0026] Preferably, the water-based defoamer is a silicone-based defoamer, and the water-based leveling agent is a polyacrylate-based leveling agent.

[0027] A method for preparing a high-performance composite coating for OSB substrates includes the following steps:

[0028] S1. Add deionized water to the mixing tank, add water-based defoamer and water-based leveling agent at a speed of 200-300 r / min, and stir for 5-10 min;

[0029] S2. Add modified expanded graphite, aluminum hypophosphite, rutile nano-titanium dioxide / montmorillonite composite material, modified potassium titanate whiskers and carbon nanotube dispersion in sequence, continue stirring for 15-20 min, and then ultrasonically disperse for 30-40 min.

[0030] S3. First, premix the waterborne epoxy acrylate emulsion and the waterborne polyurethane dispersion evenly, and then add them together with the core-shell fluorocarbon-acrylate composite emulsion into the mixture in S2. Increase the rotation speed to 400-500 r / min and stir for 20-30 min.

[0031] S4. Add environmentally friendly silane coupling agent KH-550 and water-based film-forming aid, stir for 15-20 minutes, then reduce the speed to 200-300 r / min and let it mature for 30-40 minutes.

[0032] S5. Large particulate impurities are removed by filtration through a 200-mesh filter to obtain the high-performance composite coating for the OSB board.

[0033] An application of a high-performance composite coating for OSB boards involves applying the coating to the surface of the treated OSB board by roller coating at a coating amount of 80-120 g / m², pre-baking at 80-90℃ for 1-2 hours, and then curing at 120-130℃ for 20-30 minutes.

[0034] Advantages of this invention:

[0035] 1. Superior Synergistic Performance: Core-shell fluorocarbon-acrylate emulsion provides durable weather resistance and hydrophobicity, while waterborne epoxy acrylate emulsion offers high adhesion and chemical resistance, matching the porous nature of the OSB substrate. Waterborne polyurethane dispersion adds flexibility and impact resistance, solving the problem of brittleness in single epoxy resins. The combination of these two with a core-shell fluorocarbon-acrylate composite emulsion maintains the coating's core weather resistance and flame retardant properties, complementing each other's strengths. Modified expanded graphite and aluminum hypophosphite work synergistically to exert highly efficient flame retardant effects in both the gas and condensed phases. Modified potassium titanate whiskers and carbon nanotubes form a multidimensional reinforcing network, improving mechanical properties. Silver-doped TiO2 / montmorillonite composite materials possess both photostable and antibacterial functions.

[0036] 2. Outstanding adhesion and durability: The environmentally friendly silane coupling agent forms a chemical bond between the coating and the OSB substrate, and the anchoring effect of the modified filler makes the adhesion reach level 1; at the same time, after 10 temperature change cycle tests of -20℃×2h / 60℃×2h, the coating showed no cracking or peeling, demonstrating excellent durability.

[0037] 3. Environmental protection and safety: The entire system is water-based, with a VOC content of ≤38g / L. It is free of formaldehyde and heavy metals, meets national environmental protection standards (GB 18581-2020), and can be safely used in indoor and outdoor scenarios.

[0038] 4. Strong process adaptability: The preparation process is simple and mild, requiring no high temperature and high pressure conditions, and the process parameters are easy to control; the coating process is compatible with existing OSB production lines, facilitating large-scale application without the need for large-scale equipment modification. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0040] Unless otherwise specified, all raw materials used are commercially available industrial grade. Allyloxynonylphenol polyoxyethylene ether ammonium sulfate (reactive emulsifier) ​​was purchased from Clariant. Aqueous epoxy acrylate emulsion (40% solids, Ebecryl® 2002) was purchased from Zhanxin Company. Aqueous polyurethane dispersion (40% solids, Bayhydrol UH 2647) was purchased from Covestro. Expanded graphite (80 mesh) was purchased from Changyi Dongli Graphite Products Co., Ltd. Potassium titanate whiskers were purchased from Nantong Aoxin Electronic Technology Co., Ltd. Rutile nano-titanium dioxide (NR950) was purchased from Evonik Industries, Germany. Montmorillonite (sodium-based) was purchased from Zhejiang Fenghong.

[0041] <Preparation of Core-Shell Fluorocarbon-Acrylic Emulsion>

[0042] Prepare the following ingredients by weight:

[0043] Core layer monomers: 71.5 parts of methyl methacrylate (MMA) and 28.5 parts of acrylonitrile (AN) (the weight ratio of the two is approximately 7:3, totaling 100 parts).

[0044] Shell monomers: 41 parts of hexafluorobutyl methacrylate (HFBM) and 29 parts of isooctyl acrylate (2-EHA) (the weight ratio of the two is approximately 1.4:1, totaling 70 parts).

[0045] Emulsifier: Reactive emulsifier allyloxynonylphenol polyoxyethylene ether ammonium sulfate, 1.7 parts (1.0% of the total monomer weight of 170 parts).

[0046] Initiator: Ammonium persulfate (APS), 1.7 parts (1.0% of the total weight of monomers);

[0047] Deionized water: 240 parts;

[0048] pH adjuster: ammonia water, appropriate amount.

[0049] The preparation steps are as follows:

[0050] (1) Preparation of pre-emulsion: Dissolve all emulsifiers in most of the deionized water (220 parts), stir evenly, and divide this aqueous solution into two parts; mix one part with all core layer monomers (MMA, AN), and emulsify under high speed shear for 10-15 minutes to prepare core monomer pre-emulsion; mix the other part with all shell layer monomers (HFBM, 2-EHA), and emulsify under high speed shear for 10-15 minutes to prepare shell monomer pre-emulsion;

[0051] (2) Preparation of initiator solution: Dissolve ammonium persulfate in the remaining 20 parts of deionized water to prepare an initiator aqueous solution, and divide it into three equal parts for later use;

[0052] (3) Seed emulsion preparation: Add about 1 / 10 of the pre-emulsion of the nuclear monomer to a reaction vessel equipped with a stirring, condensing and dropping device. Heat to 78±2℃, add one part of the initiator solution (accounting for 1 / 3 of the total amount), keep the reaction at this temperature for about 30 minutes until the reaction system shows a uniform and stable light blue opalescence, indicating that seed particles have formed;

[0053] (4) Core layer growth: Keep the temperature at 78±2℃, and start to add the remaining pre-emulsion of the nuclear monomer and the second initiator solution simultaneously. Control the addition rate so that both are added at a uniform rate within 2.0-2.5 hours.

[0054] (5) Shell polymerization: After the core monomer is added, there is no need to keep it warm for a long time. Immediately start to add the shell monomer pre-emulsion and the third initiator solution. Control the addition rate so that the two are added at a uniform rate within 1.5-2.0 hours. During this stage, the shell monomer polymerizes on the surface of the formed core particles to form a shell rich in fluorocarbon segments.

[0055] (6) Post-curing and post-treatment: After the shell monomers are added, the reaction system is heated to 85±1℃ and kept at that temperature for 1.0-1.5 hours to ensure that the monomers react fully and improve the conversion rate. Then, the emulsion is cooled to below 40℃ and the pH value is adjusted to 7.5-8.5 with ammonia. Finally, it is filtered through a 200-mesh filter to obtain a core-shell type fluorocarbon-acrylate composite emulsion with a solid content of about 42±1%.

[0056] <Preparation of Expanded Graphite Modified with Silane Coupling Agent KH-560>

[0057] Add 10 parts of expanded graphite to an ethanol solution (total weight 24 parts) containing 1.2 parts of silane coupling agent KH-560, and ultrasonically disperse for 35 min. Dry at 85℃ for 2.5 h, grind and pass through a 200-mesh sieve, and set aside for later use.

[0058] <Preparation of Potassium Titanate Whiskers Modified with Silane Coupling Agent KH-570>

[0059] By weight, 10 parts of potassium titanate whiskers were added to an ethanol solution (total weight 25 parts) containing 1 part of silane coupling agent KH-570, and ultrasonically dispersed for 30 min. The mixture was then dried at 95℃ for 2 h, ground through a 300-mesh sieve, and set aside for later use.

[0060] <Preparation of silver ion-doped rutile nano-titanium dioxide / montmorillonite composite materials>

[0061] By weight, 30 parts of montmorillonite were dispersed in 200 parts of deionized water and sonicated for 25 min. 10 parts of rutile nano-titanium dioxide and 0.2 parts of silver nitrate were added, and the mixture was stirred for 30 min. The pH was adjusted to 4.0 with 1.5 wt% nitric acid, and the reaction was carried out at 65℃ for 2.5 h. The mixture was filtered, washed with water until neutral, dried at 108℃ for 5 h, and then ground through a 300-mesh sieve for later use.

[0062] <Example 1>

[0063] A high-performance composite coating for OSB boards has the following components by weight:

[0064] The following components were selected: 40 parts core-shell fluorocarbon-acrylate composite emulsion, 13 parts waterborne epoxy acrylate emulsion (40% solid content), 7 parts waterborne polyurethane dispersion (40% solid content), 11 parts modified expanded graphite, 4 parts aluminum hypophosphite, 3 parts potassium titanate whiskers modified with silane coupling agent KH-570, 2 parts carbon nanotube dispersion (5wt%), 7 parts silver ion-doped rutile nano-titanium dioxide / montmorillonite composite material, 5 parts waterborne film-forming aid (weight ratio: dipropylene glycol methyl ether acetate: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate = 1:1.3), 2.5 parts silane coupling agent KH-550, 0.8 parts waterborne silicone defoamer, 0.5 parts waterborne polyacrylate leveling agent, and 12 parts deionized water.

[0065] Preparation method:

[0066] S1. Pre-dispersion: Add deionized water to the mixing tank, add water-based silicone defoamer and water-based polyacrylate leveling agent at 250 r / min, and stir for 8 min;

[0067] S2. Dispersion of functional components: While maintaining the rotation speed, add modified expanded graphite, aluminum hypophosphite, rutile nano-titanium dioxide / montmorillonite composite material, modified potassium titanate whiskers, and carbon nanotube dispersion, stir for 18 min, and then sonicate for 35 min.

[0068] S3. Film-forming system mixing: First, premix the waterborne epoxy acrylate emulsion and the waterborne polyurethane dispersion evenly, and then add them together with the core-shell fluorocarbon-acrylate composite emulsion into the mixture in S2. Increase the rotation speed to 450 r / min and stir for 25 min.

[0069] S4. Additives and curing: Add environmentally friendly silane coupling agent KH-550 and water-based film-forming aid, stir for 18 minutes, then reduce the speed to 250 r / min and cure for 35 minutes.

[0070] S5. Filtration: Pass through a 200-mesh filter to obtain a composite coating.

[0071] Application process: After the OSB board is sanded and dusted, the coating is applied to the surface of the treated OSB board by roller coating, with a coating amount of 100g / m², pre-baking at 85℃ for 1.5h, and curing at 125℃ for 25min.

[0072] <Example 2>

[0073] Composite coating components: 35 parts core-shell fluorocarbon-acrylate composite emulsion, 12 parts waterborne epoxy acrylate emulsion, 5 parts waterborne polyurethane dispersion, 10 parts modified expanded graphite, 3 parts aluminum hypophosphite, 2 parts modified potassium titanate whiskers, 1 part carbon nanotube dispersion, 6 parts silver ion-doped rutile nano-titanium dioxide / montmorillonite composite material, 4 parts waterborne film-forming aid (dipropylene glycol methyl ether acetate: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate = 1:1.2), 2 parts KH-550, 0.5 parts defoamer, 0.3 parts leveling agent, and 8 parts deionized water.

[0074] Preparation method parameter adjustment: S1 200 r / min, 5 min; S2 stirring for 15 min, ultrasonication for 30 min; S3 400 r / min, 20 min; S4 stirring for 15 min, then maturing at 200 r / min for 30 min.

[0075] Application process: After the OSB board is sanded and dusted, the coating is applied to the surface of the treated OSB board by roller coating at a coating amount of 80g / m². It is pre-baked at 80℃ for 1 hour and then cured at 120℃ for 20 minutes.

[0076] <Example 3>

[0077] Composite coating components: 45 parts core-shell fluorocarbon-acrylate composite emulsion, 15 parts waterborne epoxy acrylate emulsion, 8 parts waterborne polyurethane dispersion, 12 parts modified expanded graphite, 5 parts aluminum hypophosphite, 4 parts modified potassium titanate whiskers, 3 parts carbon nanotube dispersion, 8 parts silver ion-doped rutile nano-titanium dioxide / montmorillonite composite material, 6 parts waterborne film-forming aid (ratio 1:1.5), 3 parts KH-550, 1 part defoamer, 0.8 parts leveling agent, and 15 parts deionized water.

[0078] Preparation method parameter adjustments: S1 300 r / min / 10 min; S2 stirring for 20 min / ultrasound for 40 min; S3 500 r / min / 30 min; S4 stirring for 20 min, then maturing at 300 r / min for 40 min.

[0079] Application process: After the OSB board is sanded and dusted, the coating is applied to the surface of the treated OSB board by roller coating at a coating amount of 120g / m². It is pre-baked at 90℃ for 2 hours and then cured at 130℃ for 30 minutes.

[0080] <Comparative Example 1>

[0081] Components: 40 parts of ordinary styrene-acrylic emulsion (42% solids), 13 parts of waterborne epoxy acrylate emulsion, 7 parts of waterborne polyurethane dispersion, 11 parts of unmodified expanded graphite, 4 parts of aluminum hypophosphite, 3 parts of KH-570 modified potassium titanate whiskers, 2 parts of carbon nanotube dispersion (5wt%), 7 parts of ordinary rutile nano-titanium dioxide, 5 parts of waterborne film-forming aid, 2.5 parts of KH-550, 0.8 parts of defoamer, 0.5 parts of leveling agent, and 12 parts of deionized water. The preparation and application process are the same as in Example 1.

[0082] <Comparative Example 2>

[0083] Components: 40 parts core-shell fluorocarbon-acrylate composite emulsion, 13 parts waterborne epoxy acrylate emulsion, 7 parts waterborne polyurethane dispersion, 11 parts aluminum hydroxide (replacing modified expanded graphite), 4 parts aluminum hypophosphite, 3 parts KH-570 modified potassium titanate whiskers, 2 parts carbon nanotube dispersion, 7 parts silver ion-doped rutile nano-titanium dioxide / montmorillonite composite material, and other additives as in Example 1. Preparation and application processes are the same as in Example 1.

[0084] <Comparative Example 3>

[0085] Composition: 40 parts core-shell fluorocarbon-acrylate composite emulsion, 20 parts aqueous polyurethane dispersion, 11 parts modified expanded graphite, 4 parts aluminum hypophosphite, 3 parts unmodified potassium titanate whiskers, 2 parts carbon nanotube dispersion, 7 parts silver ion-doped rutile nano-titanium dioxide / montmorillonite composite material, and other additives as in Example 1. Preparation and application processes are the same as in Example 1.

[0086] Performance Testing

[0087] The coatings prepared in the above embodiments and comparative examples were applied to OSB substrates and tested. The results are shown in the table below:

[0088] Test Project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Resistant to accelerated aging (1000h) No cracking or powdering, ΔE≤1.5 No cracking or powdering, ΔE≤1.8 No cracking or powdering; ΔE ≤ 1.2 Slight pulverization, ΔE=3.2 No cracking or powdering, ΔE≤1.6 No cracking or powdering, ΔE≤1.7 Limiting Oxygen Index (LOI) 34% 32% 36% 28% 30% 33% Adhesion (cross-cut test) Level 1 Level 1 Level 1 Level 2 Level 1 Level 2 Water resistance (72h immersion) No change, water absorption rate 2.1% No change, water absorption rate 2.5% No change, water absorption rate 1.8% Slightly whitish, water absorption rate 4.3%. No change, water absorption rate 2.3% Slightly wrinkles, water absorption rate 3.5%. Pencil hardness 4H 3H 4H 2H 3H 3H Abrasion resistance (Taber wear) 8mg 10mg 7mg 15mg 12mg 13mg Antibacterial rate (E. coli) 99.5% 99.2% 99.8% 85% 99.3% 99.0% VOC content 35g / L 32g / L 38g / L 42g / L 36g / L 37g / L

[0089] *Accelerated aging resistance is tested according to GB / T 1865-2009; antibacterial rate test is tested according to GB / T 21866-2008, and the test strain is Escherichia coli; VOC content test standard is tested according to GB / T 23986-2009.

[0090] Results Analysis: Examples 1-3 all exhibited excellent performance. Comparative Example 1, due to the use of ordinary emulsion and unmodified filler, showed a comprehensive decrease in weather resistance, flame retardancy, adhesion, abrasion resistance, and antibacterial properties, demonstrating the crucial role of base material formulation and filler modification. Comparative Example 2, by replacing modified expanded graphite with aluminum hydroxide, significantly reduced the LOI, proving that the synergistic flame-retardant effect of modified expanded graphite and aluminum hypophosphite is irreplaceable. Comparative Example 3, due to the absence of waterborne epoxy acrylate emulsion and the use of unmodified potassium titanate whiskers, resulted in a drop in adhesion to level 2 and a decrease in abrasion resistance, demonstrating that the high adhesion characteristics of waterborne epoxy acrylate and the reinforcing effect of potassium titanate whisker modification are crucial.

[0091] In summary, this invention, through the optimized composite film-forming system and the synergistic effect of multifunctional components, successfully prepared a composite coating for OSB boards with excellent comprehensive performance, solving the technical problems of uneven performance, poor adhesion, and poor environmental performance of existing OSB board coatings, and has broad application prospects.

[0092] The above embodiments are only for illustrating the technical solutions and features of the present invention, and are intended to enable those skilled in the art to implement them better. 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 are within the scope of protection of the present invention. The parts not described in detail are prior art.

Claims

1. A high-performance composite coating for OSB boards, characterized in that, The raw materials include the following components in parts by weight: 35-45 parts of core-shell fluorocarbon-acrylate composite emulsion 12-15 parts of waterborne epoxy acrylate emulsion 5-8 parts of waterborne polyurethane dispersion 10-12 parts of modified expanded graphite 3-5 parts aluminum hypophosphite 2-4 parts of modified potassium titanate whiskers 1-3 parts of carbon nanotube dispersion 6-8 parts of rutile nano-titanium dioxide / montmorillonite composite material 4-6 parts of water-based film-forming aid 2-3 parts of environmentally friendly coupling agent 0.5-1.0 parts of water-based defoamer 0.3-0.8 parts of water-based leveling agent 8-15 parts deionized water.

2. The high-performance composite coating for OSB boards according to claim 1, characterized in that, The core-shell fluorocarbon-acrylate composite emulsion is prepared by semi-continuous seed emulsion polymerization using hexafluorobutyl methacrylate and isooctyl acrylate as shell monomers, methyl methacrylate and acrylonitrile as core monomers, and reactive emulsifier. The weight ratio of core monomers to shell monomers is 10:

7. The reactive emulsifier is allyloxynonylphenol polyoxyethylene ether ammonium sulfate, with an amount of 0.8-1.2% of the total monomer weight. The initiator is ammonium persulfate, with an amount of 1% of the total monomer weight. The reaction temperature is 75-85℃, and the reaction time is 4-6 hours.

3. The high-performance composite coating for OSB boards according to claim 1, characterized in that, The modified expanded graphite is prepared by adding expanded graphite to a 3-5 wt% ethanol solution of silane coupling agent KH-560, ultrasonically dispersing for 30-40 min, drying at 80-90℃ for 2-3 h, and grinding through a 200-mesh sieve; the weight ratio of expanded graphite to silane coupling agent KH-560 is 10:1.

2.

4. The high-performance composite coating for OSB boards according to claim 1, characterized in that, The preparation method of the rutile nano-titanium dioxide / montmorillonite composite material is as follows: montmorillonite is added to deionized water and ultrasonically dispersed for 20-30 min; rutile nano-titanium dioxide and silver nitrate are added, the pH is adjusted to 3.5-4.5 with dilute nitric acid, and the reaction is carried out at 60-70℃ for 2-3 h. Then, the mixture is filtered, washed, dried, and ground through a 300-mesh sieve. The weight ratio of rutile nano-titanium dioxide to montmorillonite is 1:

3.

5. The high-performance composite coating for OSB boards according to claim 1, characterized in that, The aqueous film-forming aid is a mixture of dipropylene glycol methyl ether acetate and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate in a weight ratio of 1:(1.2-1.5).

6. The high-performance composite coating for OSB boards according to claim 1, characterized in that, The environmentally friendly coupling agent is silane coupling agent KH-550.

7. The high-performance composite coating for OSB boards according to claim 1, characterized in that, The carbon nanotube dispersion is an aqueous dispersion with a solid content of 5 wt%.

8. The high-performance composite coating for OSB boards according to claim 1, characterized in that, The modified potassium titanate whiskers are prepared by adding potassium titanate whiskers to a 2-4 wt% ethanol solution of silane coupling agent KH-570, ultrasonically dispersing for 25-35 min, drying at 90-100℃ for 1.5-2.5 h, and grinding through a 300-mesh sieve; the weight ratio of potassium titanate whiskers to silane coupling agent KH-570 is 10:(0.8-1.2).

9. A method for preparing a high-performance composite coating for OSB substrates according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Add deionized water to the mixing tank, add water-based defoamer and water-based leveling agent at a speed of 200-300 r / min, and stir for 5-10 min; S2. Add modified expanded graphite, aluminum hypophosphite, rutile nano-titanium dioxide / montmorillonite composite material, modified potassium titanate whiskers and carbon nanotube dispersion in sequence, continue stirring for 15-20 min, and then ultrasonically disperse for 30-40 min. S3. First, premix the waterborne epoxy acrylate emulsion and the waterborne polyurethane dispersion evenly, and then add them together with the core-shell fluorocarbon-acrylate composite emulsion into the mixture in S2. Increase the rotation speed to 400-500 r / min and stir for 20-30 min. S4. Add environmentally friendly silane coupling agent KH-550 and water-based film-forming aid, stir for 15-20 minutes, then reduce the speed to 200-300 r / min and let it mature for 30-40 minutes. S5. Large particulate impurities are removed by filtration through a 200-mesh filter to obtain the high-performance composite coating for the OSB board.

10. The application of a high-performance composite coating for OSB sheets according to any one of claims 1-8, characterized in that, The coating is applied to the surface of the treated OSB board by roller coating at a rate of 80-120 g / m², pre-baked at 80-90℃ for 1-2 hours, and then cured at 120-130℃ for 20-30 minutes.