Preparation method and application of graphene modified three-layer composite weather-resistant garden floor

Abstract

The application discloses a preparation method and application of a graphene modified three-layer composite weather-resistant garden floor, and belongs to the technical field of building materials. The floor comprises, from top to bottom, a graphene reinforced wear-resistant decorative layer, a graphene modified wood-plastic composite base layer and a graphene moisture-proof balance bottom layer. The floor has excellent weather resistance, water resistance, wear resistance, ultraviolet aging resistance, slip resistance and size stability, and also has good mildew resistance and antibacterial performance. In terms of weather resistance, the bending strength retention rate after 300h xenon lamp aging is over 90%. In terms of slip safety, the wet-state slip coefficient is 0.68-0.75, far exceeding the compulsory safety standard of garden walkways. In terms of mildew resistance and antibacterial performance, the antibacterial rate is greater than or equal to 99%, and the mildew resistance grade is 0, thereby avoiding problems such as mildew and blackening on the surface of the floor. The floor is suitable for ground paving of outdoor garden landscape places such as parks, scenic spots, courtyards and waterfront walkways.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a method for preparing and applying graphene-modified three-layer composite weather-resistant garden flooring. Background Technology

[0002] With the continuous advancement of urbanization and the improvement of people's living standards, the construction of garden landscapes is receiving increasing attention. Parks, scenic areas, courtyards, waterfront walkways, boardwalks, and other outdoor garden spaces are placing increasingly higher demands on ground paving materials. Ideal garden landscape flooring not only needs to possess good aesthetics and decorative properties, but also excellent weather resistance, water resistance, wear resistance, UV aging resistance, slip resistance, and sufficient mechanical strength to adapt to the complex and ever-changing outdoor climate.

[0003] Currently, the following materials are mainly used for garden landscape paving: (1) Natural stone. Such as granite and marble, which have the advantages of high strength, good wear resistance and long service life. However, natural stone resources are limited, mining costs are high, weight is heavy, transportation and installation are inconvenient, and the surface has poor anti-slip performance in humid environments, which poses certain safety hazards.

[0004] (2) Preservative-treated wood flooring. Preservative-treated pine and fir wood, for example, have naturally beautiful textures and a pleasant feel underfoot, and are widely used in garden walkways, waterfront platforms, and other similar locations. However, preservative-treated wood flooring has the following prominent problems: First, long-term exposure to the outdoor environment, affected by sun and rain, easily leads to cracking, deformation, and decay, resulting in a shorter service life; second, traditional preservative treatments often use chemical preservatives such as chromated copper arsenate (CCA), which pose certain environmental safety risks; third, timber resources are increasingly scarce, which does not meet the requirements of sustainable development.

[0005] (3) Wood-plastic composite flooring. Wood-plastic composite flooring is a new type of environmentally friendly material made of wood fiber or plant fiber and thermoplastic polymer materials (such as PE, PVC, etc.), combining the performance characteristics of wood and plastic. However, existing wood-plastic composite flooring still has many shortcomings: low mechanical properties, poor water resistance, easy to warp and deform after contact with water, insufficient resistance to ultraviolet aging, and easy to fade, powder, and become brittle after long-term outdoor use, resulting in a limited service life.

[0006] In recent years, graphene has been explored for application in flooring materials due to its excellent mechanical, thermal, and barrier properties. For example, CN108973283B discloses a three-layer outdoor composite wood-plastic composite flooring, where all three layers are wood-plastic substrates, with graphene oxide-modified polyurethane added only to the top and bottom layers. The three substrates have similar materials and functions, relying on rosin to improve compatibility and reduce water absorption. It lacks a directional moisture-proof bottom layer and an anti-UV ternary synergistic system. CN113736181A discloses carbon-modified polypropylene outdoor flooring, demonstrating that graphene can improve the weather resistance of a single substrate; CN113717671A discloses graphene-phenolic resin outdoor bamboo flooring, demonstrating that graphene can improve the mildew resistance of a single board.

[0007] However, existing technologies still have the following shortcomings: First, most existing graphene-modified flooring is a single-layer homogeneous substrate or a three-layer all-wood-plastic homogeneous structure. The amount of graphene added, the matrix resin, and the functional additives in the three layers are not differentiated, which cannot specifically match the independent working conditions of outdoor flooring: "the surface layer is wear-resistant and UV-resistant, the middle layer is load-bearing and mildew-proof, and the bottom layer is moisture-proof and water-resistant".

[0008] Second, the surface layer is only modified with graphene alone, lacking a ternary synergistic system of graphene nanosheets, nano-alumina, and ultraviolet absorbers. The effects of ultraviolet shielding and wear resistance improvement are limited, and there is no multi-level anti-slip structure of macro-texture + micro-alumina particles, which fails to meet the wet anti-slip standards in waterfront areas.

[0009] Third, the bottom and middle layers share the same polyethylene substrate, and there is no hydrophobic composite moisture-proof layer of polypropylene + glass fiber + graphene. Soil moisture continues to penetrate upwards, resulting in poor dimensional stability of the flooring.

[0010] Fourth, the lack of an interlayer corona activation process resulted in weak bonding at the interface of the three-layer hot-pressed composite, making it prone to delamination and cracking after outdoor temperature cycling.

[0011] Fifth, after rain, the waterfront walkways are slippery and prone to slipping, failing to meet the mandatory anti-slip safety standards for outdoor gardens. Summary of the Invention

[0012] To address the shortcomings of existing three-layer graphene wood-plastic composite flooring, such as homogeneous layers, limited functionality, and poor synergistic performance in weather resistance, moisture resistance, and slip resistance, this paper proposes a method for preparing and applying graphene-modified three-layer composite weather-resistant garden flooring. This method utilizes a differentiated combination of three layers: a surface layer of wear-resistant and UV-resistant system, a middle layer of high-strength anti-mildew wood-plastic composite system, and a bottom layer of graphene hydrophobic barrier system. Combined with an interlayer activation hot-pressing process, this method simultaneously achieves high wear resistance, UV aging resistance, low water absorption, high wet slip resistance, and long-lasting anti-mildew and antibacterial properties.

[0013] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a graphene-modified three-layer composite weather-resistant garden floor, the floor comprising, from top to bottom, a graphene-reinforced wear-resistant decorative layer, a graphene-modified wood-plastic composite base layer, and a graphene moisture-proof and balancing bottom layer. The graphene-reinforced wear-resistant decorative layer comprises the following raw materials in parts by weight: 0.5-3 parts graphene nanosheets, 15-30 parts nano-alumina, 60-80 parts melamine-formaldehyde resin, 1-3 parts ultraviolet absorber, and 0.5-2 parts curing agent; the ultraviolet absorber is 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-benzotriazole or 2-hydroxy-4-n-octyloxybenzophenone; the curing agent is ammonium chloride; The graphene-modified wood-plastic composite base layer comprises the following raw materials in parts by weight: 1-6 parts graphene nanosheets, 60-100 parts polyethylene resin, 30-60 parts plant fiber powder, 20-40 parts calcium carbonate, 2-5 parts coupling agent, 1-3 parts compatibilizer maleic anhydride grafted polyethylene, 0.5-2 parts lubricant, 0.1-0.5 parts antioxidant 1010, 1-5 parts impact modifier, and 0.5-2 parts antifungal and antibacterial agent; the plant fiber powder is a 1:1 mixture of 100-mesh bamboo powder or 50-mesh wood powder and straw powder; the coupling agent is silane coupling agent KH550 or titanate coupling agent NDZ-101; the antifungal and antibacterial agent is nano silver or nano zinc oxide; the lubricant is stearic acid or zinc stearate; and the impact modifier is ethylene-octene copolymer. The graphene moisture-proof balancing bottom layer comprises the following raw materials in parts by weight: 0.5-2 parts graphene nanosheets, 50-80 parts polypropylene resin, 10-20 parts glass fiber, 3-8 parts hydrophobic modifier, and 0.1-0.5 parts antioxidant 1010. The hydrophobic modifier is polydimethylsiloxane.

[0014] Furthermore, the total thickness of the flooring is 20-40mm; of which: the thickness of the graphene-reinforced wear-resistant decorative layer is 0.3-0.8mm; the thickness of the graphene-modified wood-plastic composite base layer is 19-38mm; and the thickness of the graphene moisture-proof and balancing bottom layer is 0.7-1.2mm.

[0015] Furthermore, the graphene nanosheets have 1-10 layers, a sheet diameter of 0.5-5 μm, and a thickness of 0.5-5 nm.

[0016] A second aspect of the present invention provides a method for preparing graphene-modified three-layer composite weather-resistant garden flooring according to any one of the claims, comprising the following steps: (1) Preparation of graphene-reinforced wear-resistant decorative layer: Graphene nanosheets, nano-alumina and ultraviolet absorber are added to melamine-formaldehyde resin according to the formula, and mixed evenly to obtain a uniform wear-resistant resin slurry; a curing agent is added to the wear-resistant resin slurry, and after stirring evenly, the slurry is uniformly coated onto the surface of decorative paper by roller coating or spraying; the coated decorative paper is dried and cured to obtain a graphene-reinforced wear-resistant decorative layer. (2) Preparation of graphene-modified wood-plastic composite base layer: Graphene nanosheets, coupling agent, compatibilizer maleic anhydride-grafted polyethylene, lubricant, antioxidant 1010, impact modifier, and antifungal and antibacterial agent are mixed with polyethylene resin in the following proportions for the first time; plant fiber powder and calcium carbonate are added to the mixture and mixed again to obtain a premix; the premix is ​​melt-blended and extruded, and after extrusion, it is cooled and pelletized to obtain graphene-modified wood-plastic composite base layer granules; the graphene-modified wood-plastic composite base layer granules are extruded or hot-pressed to produce graphene-modified wood-plastic composite base layer boards; (3) Preparation of graphene-modified wood-plastic composite base layer: Graphene nanosheets, glass fiber, hydrophobic modifier, and antioxidant are mixed evenly with polypropylene resin according to the specified ratio; the mixture is melt-blended and extruded, and after extrusion, it is cooled and granulated to obtain graphene moisture-proof and balancing bottom layer granules; the graphene moisture-proof and balancing bottom layer granules are extruded or hot-pressed to make graphene moisture-proof and balancing bottom layer boards. (4) Molding of composite flooring: The graphene-reinforced wear-resistant decorative layer, the graphene-modified wood-plastic composite base layer, and the graphene moisture-proof and balancing bottom layer are stacked in order from top to bottom, hot-pressed, and cooled to obtain the graphene-modified three-layer composite weather-resistant garden floor.

[0017] Furthermore, in step (1): When mixing, disperse at a speed of 2000-4000 r / min for 30-60 min to obtain a uniform wear-resistant resin slurry; when coating, the coating amount is 100-200 g / m²; when drying and curing, dry and cure at 80-120℃ for 10-30 min.

[0018] Furthermore, in step (2): The initial mixing temperature is 100-120℃ and the mixing time is 10-20 min; the second mixing time is 10-15 min; the extrusion temperature is 160-200℃ and the rotation speed is 80-150 r / min; the plant fiber powder is dried at 80-100℃ until the moisture content is below 3% before use.

[0019] Furthermore, in step (3): The mixing temperature is 120-140℃ and the mixing time is 10-20 min; the extrusion temperature during melt blending extrusion is 180-220℃ and the screw speed is 100-200 r / min.

[0020] Furthermore, in step (4): During hot pressing, the material is hot-pressed at 160-200℃ and 5-15MPa for 5-15 minutes.

[0021] Furthermore, before stacking, the upper and lower surfaces of the graphene-modified wood-plastic composite substrate are subjected to corona treatment or plasma treatment, with a corona power of 800-1200W and a treatment speed of 3-6m / min.

[0022] The beneficial effects of this invention are: (1) Excellent overall weather resistance. This invention introduces graphene nanosheets and nano-alumina into the wear-resistant decorative layer to form a surface protective layer with high hardness and high wear resistance; the two-dimensional sheet structure of graphene has excellent ultraviolet light blocking ability, and with the synergistic effect of ultraviolet absorbers, it can effectively shield and absorb ultraviolet light, significantly delay the aging and degradation of the material, and the flexural strength retention rate after 300h xenon lamp aging is over 90%.

[0023] (2) Excellent water resistance and dimensional stability. This invention incorporates graphene nanosheets into the wood-plastic composite base layer. The layered structure of graphene forms a physical barrier network in the composite material, effectively preventing the penetration and diffusion of water molecules, significantly reducing the water absorption rate and thickness expansion rate of the flooring. Simultaneously, the exclusive design of the graphene moisture-proof and balancing bottom layer—a polypropylene + glass fiber + graphene hydrophobic composite layer—further blocks the upward movement of moisture from the base soil, solving the problem of warping and deformation caused by long-term outdoor dampness.

[0024] (3) Excellent anti-slip safety. The present invention has a microscopic protrusion structure of nano-alumina particles on the upper surface of the graphene-reinforced wear-resistant decorative layer, forming a multi-level anti-slip surface that combines macroscopic and microscopic properties. According to GB / T41000-2021 "Anti-slip Flooring Anti-slip Performance Test and Grading", the wet anti-slip coefficient of outdoor waterfront places is ≥0.6 to meet the safety requirements. The wet anti-slip coefficient of the present invention is 0.68-0.75, which far exceeds the mandatory safety standard for garden walkways. There is no risk of slipping after rain or in waterfront areas.

[0025] (4) Excellent anti-mold and antibacterial properties. The present invention adds an anti-mold and antibacterial agent to the wood-plastic composite base layer, which effectively inhibits the growth of mold and bacteria in the outdoor humid environment. The antibacterial rate is ≥99% and the anti-mold level is 0, which avoids problems such as mold and blackening on the floor surface and ensures the hygiene and beauty of the garden landscape.

[0026] (5) Environmentally friendly. This invention uses wood-plastic composite material as the basis, making full use of renewable plant resources such as bamboo powder and wood powder, reducing wood consumption; the addition of graphene can achieve significant performance improvement with a small amount, and the material can be recycled and reused, which meets the requirements of green environmental protection and sustainable development. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the graphene-modified three-layer composite weather-resistant garden flooring of Example 1. Detailed Implementation

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] As introduced in the background technology section, outdoor garden flooring not only needs to have good aesthetics and decoration, but also needs to have excellent weather resistance, water resistance, wear resistance, UV aging resistance, anti-slip performance, and sufficient mechanical strength to adapt to the complex and ever-changing outdoor climate environment. Existing garden landscape flooring generally cannot meet all of the above requirements at the same time.

[0030] Based on this, the purpose of this invention is to provide a graphene-modified composite weather-resistant garden floor. The composite sports floor of this invention has a three-layer composite structure. By introducing graphene nanosheets and nano-alumina into the wear-resistant decorative surface layer, a high-hardness, high-wear-resistant surface protective layer is formed. The two-dimensional sheet structure of graphene has excellent ultraviolet light blocking ability, and with the synergistic effect of ultraviolet absorbers, it can effectively shield and absorb ultraviolet light, significantly delaying the aging and degradation of the material. By adding graphene nanosheets to the wood-plastic composite base layer to form a physical barrier network, the penetration and diffusion of water molecules are effectively prevented, significantly reducing the water absorption rate and thickness expansion rate of the floor. By setting a graphene moisture-proof balancing bottom layer, moisture from the base soil is further blocked, ensuring the dimensional stability of the floor in humid environments. In addition, a microscopic protrusion structure of nano-alumina particles is set on the upper surface of the graphene-reinforced wear-resistant decorative layer to form an anti-slip surface. Anti-mildew and antibacterial agents are added to the wood-plastic composite base layer to inhibit the growth of mold and bacteria in humid outdoor environments, preventing the floor surface from becoming moldy and blackening, ensuring the floor's aesthetics and hygiene.

[0031] The core innovations of this invention are as follows: 1. Functional hierarchical design of three-layer heterogeneous differential graphene Surface layer: melamine resin matrix, low-doped graphene + nano alumina + UV absorber ternary synergy, specially designed to achieve surface wear resistance and UV blocking; Middle layer: Polyethylene wood-plastic matrix with the highest graphene content, combined with anti-mildew and antibacterial agents, bearing load, resisting impact, and inhibiting bacteria inside; Bottom layer: Polypropylene + glass fiber matrix, graphene + hydrophobic modifier compounded to form a one-way water-proof barrier layer to block underground moisture; 2. The bottom layer of graphene and the hydrophobic modifier work synergistically to block water. Two-dimensional graphene sheets form tortuous water permeation channels, and hydrophobic modifiers fill the interface gaps, providing a double barrier against water molecules. Graphene alone can only slightly reduce the water absorption rate, but the combination of the two achieves a significant reduction in water absorption rate, a combination that existing single-layer / triple-layer homogeneous flooring does not possess.

[0032] 3. Interlayer corona activation composite process The three-layer wood-plastic composite flooring has poor compatibility with different resin systems (melamine / PE / PP). Corona treatment improves the interfacial polarity, and the peel strength is increased by more than 40% after hot pressing. Existing three-layer wood-plastic composite flooring does not have a cross-resin interface activation process.

[0033] This invention innovatively adopts a three-layer heterogeneous differential graphene composite structure. The amount of matrix resin, graphene doping and functional additives in each layer are precisely matched to the corresponding working conditions, so as to achieve long-lasting weather resistance, water resistance and moisture resistance, high anti-slip and mildew and antibacterial properties. It is specially adapted to the complex outdoor garden environment such as parks, waterfronts and courtyards.

[0034] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0035] The test materials used in the embodiments of the present invention, unless otherwise specified, are all conventional test materials in the art and can be purchased through commercial channels. The CAS number for melamine-formaldehyde resin is 3089-11-0; the CAS number for 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-benzotriazole is 3846-71-7; the CAS number for polyethylene resin is 9002-88-4; the CAS number for maleic anhydride-grafted polyethylene is 9006-26-2; the CAS number for stearic acid is 57-11-4; the CAS number for pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] is 6683-19-8; the CAS number for polypropylene resin is 9003-07-0; the CAS number for melamine-formaldehyde resin is 3089-11-0; the CAS number for 2-hydroxy-4-n-octyloxybenzophenone is 1843-05-6; and the CAS number for zinc stearate is 557-05-1.

[0036] Example 1: Preparation of graphene-modified three-layer composite weather-resistant garden flooring A graphene-modified three-layer composite weather-resistant garden floor with a total thickness of 30mm; a graphene-reinforced wear-resistant decorative layer with a thickness of 0.5mm, a graphene-modified wood-plastic composite base layer with a thickness of 28.7mm, and a graphene moisture-proof and balancing bottom layer with a thickness of 0.8mm.

[0037] (I) Preparation of graphene-reinforced wear-resistant decorative layer The weight ratio is as follows: 1.5 parts graphene nanosheets (3-5 layers, sheet diameter 1-3μm, manufacturer: Changzhou Sixth Element Material Technology Co., Ltd., item number SE1430), 20 parts nano aluminum oxide (CAS No. 1344-28-1), 75 parts melamine formaldehyde resin (CAS No. 3089-11-0), 2 parts 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-benzotriazole (CAS No. 3846-71-7), and 1 part curing agent (ammonium chloride, CAS No. 12125-02-9).

[0038] Process: Graphene nanosheets, nano-alumina, and the UV absorber 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-benzotriazole were added to melamine-formaldehyde resin and dispersed in a high-speed disperser at 3000 rpm for 45 min to obtain a uniform wear-resistant resin slurry. After adding a curing agent and stirring evenly, the slurry was uniformly coated onto the surface of decorative paper using a roller coating method, with a coating amount of 150 g / m². The coated decorative paper (Lanling Jason Decorative Materials Co., Ltd.) was dried and cured at 100℃ for 20 min to obtain a graphene-reinforced wear-resistant decorative layer.

[0039] (II) Preparation of graphene-modified wood-plastic composite base layer The composition by weight is as follows: 3 parts graphene nanosheets, 80 parts polyethylene resin (CAS No. 9002-88-4), 45 parts 100-mesh bamboo powder (Linyi Luyuan Wood Powder Factory), 30 parts calcium carbonate, 3 parts silane coupling agent KH550, 2 parts maleic anhydride grafted polyethylene (CAS No. 9006-26-2), 1 part stearic acid (CAS No. 57-11-4), 0.3 parts antioxidant 1010 (CAS No. 6683-19-8), 3 parts impact modifier (ethylene-octene copolymer, CAS No. 26221-73-8), and 1 part nano silver (CAS No. 7440-22-4) antibacterial agent.

[0040] Process: Bamboo powder is dried at 90℃ until the moisture content is below 3%. Graphene nanosheets, coupling agent, compatibilizer maleic anhydride-grafted polyethylene (CAS: 9006-26-2), lubricant stearic acid (CAS: 57-11-4), antioxidant 1010, impact modifier, and antifungal and antibacterial agent are mixed evenly with polyethylene resin in a high-speed mixer at 110℃ for 15 minutes. The dried bamboo powder and calcium carbonate are added to the mixture, and mixing continues for 12 minutes to obtain a premix. The premix is ​​fed into a twin-screw extruder for melt blending and extrusion at 180℃ and a screw speed of 120 r / min. After extrusion, the mixture is cooled and pelletized to obtain graphene-modified wood-plastic composite base layer granules. The granules are then extruded to form graphene-modified wood-plastic composite base layer boards.

[0041] (III) Preparation of graphene moisture-proof balancing substrate The weight ratio is as follows: 1 part graphene nanosheets, 65 parts polypropylene resin (CAS No. 9003-07-0), 15 parts glass fiber (CAS: 65997-17-3), 5 parts hydrophobic modifier (polydimethylsiloxane, CAS No. 9016-00-6), and 0.3 parts antioxidant 1010.

[0042] Process: The above raw materials are mixed evenly in a high-speed mixer at a mixing temperature of 130℃ for 15 minutes. The mixture is then fed into a twin-screw extruder for melt blending and extrusion at a temperature of 200℃ and a screw speed of 150 r / min. After extrusion, the mixture is cooled and pelletized to obtain graphene moisture-proof balancing bottom layer granules. The granules are then extruded to form graphene moisture-proof balancing bottom layer boards.

[0043] (iv) Molding of composite flooring Process: The graphene-reinforced wear-resistant decorative layer, the graphene-modified wood-plastic composite base layer, and the graphene moisture-proof balancing bottom layer are stacked sequentially from top to bottom. (Before stacking, the upper and lower surfaces of the wood-plastic composite base layer are subjected to corona treatment (corona power 1000W, treatment speed 4.5m / min). The layers are then hot-pressed in a hot press at 180℃ and 10MPa for 10 minutes. After cooling, the graphene-modified three-layer composite weather-resistant garden flooring is obtained. Further cutting, tongue and groove cutting, and surface processing with anti-slip textures are possible.

[0044] Example 2: Preparation of graphene-modified three-layer composite weather-resistant garden flooring A graphene-modified three-layer composite weather-resistant garden floor has a total thickness of 32mm; the graphene-reinforced wear-resistant decorative layer is 0.6mm thick, the graphene-modified wood-plastic composite base layer is 30.4mm thick, and the graphene moisture-proof and balancing bottom layer is 1.0mm thick; the only difference is the adjustment of the raw material ratio, and the rest of the preparation process is the same as in Example 1.

[0045] Graphene-reinforced wear-resistant decorative layer: 2.5 parts graphene nanosheets, 25 parts nano aluminum oxide, 68 parts melamine-formaldehyde resin, 2.5 parts 2-hydroxy-4-n-octyloxybenzophenone, and 1.5 parts curing agent (ammonium chloride, CAS No. 12125-02-9); Graphene-modified wood-plastic composite base layer: 5 parts graphene nanosheets, 70 parts polyethylene resin, 50 parts 150-mesh wood flour / straw flour 1:1 mixture (Linyi Luyuan Wood Flour Factory), 35 parts calcium carbonate, 4 parts titanate coupling agent NDZ-101 (CAS No. 61417-49-0), 2.5 parts maleic anhydride grafted polyethylene, 1.5 parts zinc stearate (CAS: 557-05-1), 0.4 parts antioxidant 1010, 4 parts impact modifier (ethylene-octene copolymer, CAS No. 26221-73-8), and 1.5 parts nano zinc oxide (CAS No. 1314-13-2) antibacterial agent; Graphene moisture-proof and balancing bottom layer: 1.8 parts graphene nanosheets, 60 parts polypropylene resin, 18 parts glass fiber, 6 parts hydrophobic modifier (polydimethylsiloxane, CAS No. 9016-00-6), and 0.4 parts antioxidant 1010.

[0046] Example 3: Preparation of graphene-modified three-layer composite weather-resistant garden flooring A graphene-modified three-layer composite weather-resistant garden floor has a total thickness of 28mm; the graphene-reinforced wear-resistant decorative layer is 0.4mm thick, the graphene-modified wood-plastic composite base layer is 26.8mm thick, and the graphene moisture-proof and balancing bottom layer is 0.8mm thick; the raw material ratio is the same as in Example 1, and the rest of the preparation process is completely consistent.

[0047] Comparative Example 1 It uses commercially available ordinary outdoor wood-plastic composite flooring, which does not contain graphene components.

[0048] This ordinary outdoor wood-plastic composite flooring was purchased from Linyi Luyuan New Material Co., Ltd., and the product model is Luyuan WS-140 outdoor PE wood-plastic composite flooring; it does not contain graphene, has no three-layer differentiated composite structure, no surface wear-resistant and UV-resistant coating, and no independent moisture-proof bottom layer.

[0049] Comparative Example 2 The formulation and preparation method of Example 1 are used, but graphene nanosheets are not added to the wood-plastic composite base layer.

[0050] Comparative Example 3 The formulation and preparation method of Example 1 are used, but without the graphene moisture-proof and balancing bottom layer, only two layers are composited.

[0051] Test case According to national standards GB / T 24508-2020 "Wood-Plastic Composite Flooring", GB / T 16422.2-2022 "Laboratory Light Source Exposure Test Methods for Plastics - Part 2: Xenon Arc Lamp", JGJ / T 331-2014 "Technical Specification for Anti-Slip of Building Flooring Engineering", LY / T1926-2020 "Testing and Grading of Antibacterial Properties of Wood-based Panels and Wood (Bamboo) Products", and LY / T 2230-2013 "Evaluation of Anti-mildew Performance of Wood-based Panels", the flooring prepared in Examples 1-3 and Comparative Examples 1-3 were tested for performance (6 tests per group, average value was taken), and the results are shown in Table 1.

[0052] Table 1. Floor performance test results (1) The bending strength and elastic modulus of the example are much higher than those of all the comparative examples; the mechanical properties of Comparative Example 2 decreased significantly after the middle layer of graphene was removed, proving that high-doped middle layer of graphene can significantly enhance the structural strength of wood-plastic composite material.

[0053] (2) Comparative Example 3 had no independent moisture-proof bottom layer and Comparative Example 2 had no middle layer graphene. The water absorption rate and expansion rate increased significantly. This confirms that the dual synergistic water blocking effect of the middle layer graphene barrier network and the bottom layer graphene hydrophobic polypropylene layer is a combination effect that existing three-layer homogeneous flooring does not have.

[0054] (3) The surface graphene + nano alumina binary hard filler work together, and the wear amount is only 1 / 4-1 / 5 of that of commercial flooring. The comparative documents only have single graphene modification, and the wear resistance improvement is far lower than that of the ternary wear-resistant coating of this invention.

[0055] (4) The combination of graphene nanosheets for UV shielding and organic UV absorbers results in a strength retention rate of over 90% after aging; existing technologies only improve the weather resistance of single carbon materials and do not have a binary UV protection system.

[0056] (5) The Technical Specification for Anti-slip of Building Ground Engineering (JGJ / T 331-2014) stipulates that the wet anti-slip value of outdoor water-walking trails is ≥80, which is a high anti-slip level (Aw level); the wet coefficient of all embodiments of the present invention exceeds 80, and the highest of Embodiment 3 is 86. The anti-slip effect cannot be achieved by a single substrate.

[0057] (6) The medium-layer long-lasting antibacterial agent combined with graphene inhibits mold adhesion, preventing mold and blackening in humid outdoor environments, achieving a mold prevention level of 0, and meeting the long-term outdoor hygiene needs of garden landscapes.

[0058] This invention provides graphene-modified three-layer composite weather-resistant garden flooring suitable for all outdoor garden paving scenarios, including urban parks, tourist attractions, courtyards, terraces, waterfront boardwalks, waterfront walkways, and landscape platforms.

[0059] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A graphene-modified three-layer composite weather-resistant garden floor, characterized in that, The flooring comprises, from top to bottom, a graphene-reinforced wear-resistant decorative layer, a graphene-modified wood-plastic composite base layer, and a graphene moisture-proof and balancing bottom layer. The graphene-reinforced wear-resistant decorative layer comprises the following raw materials in parts by weight: 0.5-3 parts graphene nanosheets, 15-30 parts nano-alumina, 60-80 parts melamine-formaldehyde resin, 1-3 parts ultraviolet absorber, and 0.5-2 parts curing agent; the ultraviolet absorber is 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-benzotriazole or 2-hydroxy-4-n-octyloxybenzophenone; the curing agent is ammonium chloride; The graphene-modified wood-plastic composite base layer comprises the following raw materials in parts by weight: 1-6 parts graphene nanosheets, 60-100 parts polyethylene resin, 30-60 parts plant fiber powder, 20-40 parts calcium carbonate, 2-5 parts coupling agent, 1-3 parts compatibilizer maleic anhydride grafted polyethylene, 0.5-2 parts lubricant, 0.1-0.5 parts antioxidant 1010, 1-5 parts impact modifier, and 0.5-2 parts antifungal and antibacterial agent; the plant fiber powder is a 1:1 mixture of 100-mesh bamboo powder or 50-mesh wood powder and straw powder; the coupling agent is silane coupling agent KH550 or titanate coupling agent NDZ-101; the antifungal and antibacterial agent is nano silver or nano zinc oxide; the lubricant is stearic acid or zinc stearate; and the impact modifier is ethylene-octene copolymer. The graphene moisture-proof balancing bottom layer comprises the following raw materials in parts by weight: 0.5-2 parts graphene nanosheets, 50-80 parts polypropylene resin, 10-20 parts glass fiber, 3-8 parts hydrophobic modifier, and 0.1-0.5 parts antioxidant 1010. The hydrophobic modifier is polydimethylsiloxane.

2. The graphene-modified three-layer composite weather-resistant garden flooring according to claim 1, characterized in that, The total thickness of the flooring is 20-40mm; of which: the graphene-reinforced wear-resistant decorative layer is 0.3-0.8mm thick; the graphene-modified wood-plastic composite base layer is 19-38mm thick; and the graphene moisture-proof and balancing bottom layer is 0.7-1.2mm thick.

3. The graphene-modified three-layer composite weather-resistant garden flooring according to claim 1, characterized in that, The graphene nanosheets have 1-10 layers, a diameter of 0.5-5 μm, and a thickness of 0.5-5 nm.

4. The method for preparing the graphene-modified three-layer composite weather-resistant garden flooring according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Preparation of graphene-reinforced wear-resistant decorative layer: Graphene nanosheets, nano-alumina and ultraviolet absorber are added to melamine-formaldehyde resin according to the formula, and mixed evenly to obtain a uniform wear-resistant resin slurry; a curing agent is added to the wear-resistant resin slurry, and after stirring evenly, the slurry is uniformly coated onto the surface of decorative paper by roller coating or spraying; the coated decorative paper is dried and cured to obtain a graphene-reinforced wear-resistant decorative layer. (2) Preparation of graphene-modified wood-plastic composite base layer: Graphene nanosheets, coupling agent, compatibilizer maleic anhydride-grafted polyethylene, lubricant, antioxidant 1010, impact modifier, and antifungal and antibacterial agent are mixed with polyethylene resin in the following proportions for the first time; plant fiber powder and calcium carbonate are added to the mixture and mixed again to obtain a premix; the premix is ​​melt-blended and extruded, and after extrusion, it is cooled and pelletized to obtain graphene-modified wood-plastic composite base layer granules; the graphene-modified wood-plastic composite base layer granules are extruded or hot-pressed to produce graphene-modified wood-plastic composite base layer boards; (3) Preparation of graphene-modified wood-plastic composite base layer: Graphene nanosheets, glass fiber, hydrophobic modifier, and antioxidant are mixed evenly with polypropylene resin according to the specified ratio; the mixture is melt-blended and extruded, and after extrusion, it is cooled and granulated to obtain graphene moisture-proof and balancing bottom layer granules; the graphene moisture-proof and balancing bottom layer granules are extruded or hot-pressed to make graphene moisture-proof and balancing bottom layer boards. (4) Molding of composite flooring: The graphene-reinforced wear-resistant decorative layer, the graphene-modified wood-plastic composite base layer, and the graphene moisture-proof and balancing bottom layer are stacked in order from top to bottom, hot-pressed, and cooled to obtain the graphene-modified three-layer composite weather-resistant garden floor.

5. The preparation method according to claim 4, characterized in that, In step (1): When mixing, disperse at a speed of 2000-4000 r / min for 30-60 min to obtain a uniform wear-resistant resin slurry; when coating, the coating amount is 100-200 g / m²; when drying and curing, dry and cure at 80-120℃ for 10-30 min.

6. The preparation method according to claim 4, characterized in that, In step (2): The initial mixing temperature is 100-120℃ and the mixing time is 10-20 min; the second mixing time is 10-15 min; the extrusion temperature is 160-200℃ and the rotation speed is 80-150 r / min; the plant fiber powder is dried at 80-100℃ until the moisture content is below 3% before use.

7. The preparation method according to claim 4, characterized in that, In step (3): The mixing temperature is 120-140℃ and the mixing time is 10-20 min; the extrusion temperature during melt blending extrusion is 180-220℃ and the screw speed is 100-200 r / min.

8. The preparation method according to claim 4, characterized in that, In step (4): During hot pressing, the material is hot-pressed at 160-200℃ and 5-15MPa for 5-15 minutes.

9. The preparation method according to claim 8, characterized in that, Before stacking, the upper and lower surfaces of the graphene-modified wood-plastic composite substrate are subjected to corona treatment or plasma treatment, with a corona power of 800-1200W and a treatment speed of 3-6m / min.

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