Multi-layer composite hot press molding method for stone-plastic floor

Abstract

The invention relates to the technical field of polymer composite materials, in particular to a stone-plastic floor multi-layer composite hot press molding method which comprises the following components in parts by mass: 100-120 parts of modified polyvinyl chloride resin; 10 to 15 parts of nano silicon dioxide; 0.5 to 1.5 parts of graphene; 5-8 parts of a composite heat stabilizer; 8 to 12 parts of high-density oxidized polyethylene wax; 3-5 parts of a paraffin-based microcapsule phase change material; 15 to 20 parts of ultraviolet curing resin; 4-6 parts of ceramic particles; 20-25 parts of a polyvinyl chloride base film; and 1-3 parts of a nano titanium dioxide whitening agent. Through collaborative design of a hot press molding process and a multi-component material, the mechanical property, the thermal stability and the decorative effect of the stone-plastic floor are remarkably improved, and meanwhile, the stone-plastic floor has the characteristics of energy conservation and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically to a method for multi-layer composite hot-pressing molding of stone-plastic flooring. Background Technology

[0002] Stone plastic (SPL) flooring, due to its lightweight, wear-resistant, and waterproof properties, is widely used in the building decoration field, especially in commercial spaces, residential environments, and industrial settings. Currently, the industry places higher demands on the manufacturing technology of SPL flooring: firstly, it requires multi-layer composite structure design to achieve functional zoning; secondly, it demands high-precision control of the molding process to ensure the interfacial bonding strength and overall stability between the material layers; and thirdly, it must meet stringent environmental regulations regarding low volatile organic compound emissions, recyclability, and energy efficiency. Furthermore, the rapid response to market customization demands is driving the development of intelligent and flexible production systems.

[0003] To address the aforementioned needs, the following targeted solutions have been proposed in the current technological field: Multi-layer co-extrusion molding technology: Different functional materials are simultaneously molded using multi-layer extrusion equipment, and interlayer bonding is achieved by using a melt bonding mechanism, reducing subsequent processing steps; Laser-assisted hot pressing system: Employs laser local heating technology to precisely control the hot pressing temperature distribution, improving the forming accuracy of complex-shaped products; Plant-based polymer alternatives: Introducing starch-modified resins as a base material reduces carbon emissions and improves the biodegradability of materials.

[0004] Despite the progress made by the above solutions in specific areas, the following shortcomings still exist: The contradiction between molding efficiency and cost: Multi-layer co-extrusion technology relies on high-precision equipment, and the high investment and maintenance costs of equipment limit the feasibility of small and medium-sized production; Limited functional integration: Although laser-assisted hot pressing can optimize temperature control, it is difficult to simultaneously meet the differentiated performance requirements of multilayer materials; Material performance compromises: Plant-based polymers lag behind traditional petrochemical-based materials in terms of mechanical properties and durability, which limits the application scenarios of the products and narrows the processing window. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a multi-layer composite hot-pressing molding method for stone-plastic flooring, which solves the problems mentioned above.

[0006] According to a first aspect of the present invention, a multi-layer composite hot-pressed stone-plastic flooring is provided, wherein the stone-plastic flooring is composed of the following components in parts by weight: Modified polyvinyl chloride resin: 100-120 parts; Nano silica: 10-15 parts; Graphene: 0.5–1.5 parts; Composite heat stabilizer: 5-8 parts; High-density oxidized polyethylene wax: 8-12 parts; Paraffin-based microcapsule phase change material: 3-5 parts; UV-curable resin: 15-20 parts; Ceramic particles: 4-6 parts; Polyvinyl chloride film: 20-25 parts; Nano titanium dioxide whitening agent: 1-3 parts.

[0007] Modified polyvinyl chloride (MPVC) resin is used as a base material to provide structural strength and flexibility. Modification processes reduce material brittleness and improve impact resistance, while adjustments to the molecular chain structure enhance thermal stability.

[0008] Nano-silica dioxide (NSD) is used as a reinforcing filler to improve the hardness and wear resistance of materials. Its nanoscale particle size can fill the microscopic gaps in the modified polyvinyl chloride resin matrix, forming a dense network structure, improving the mechanical properties and weather resistance of the material, and reducing surface scratches and wear.

[0009] Graphene (G) serves as a functional additive, enhancing the electrical and thermal conductivity of materials. Its two-dimensional layered structure can be dispersed in resins to form conductive pathways, reduce the coefficient of thermal expansion, and simultaneously strengthen interfacial bonding, thereby improving the material's resistance to crack propagation.

[0010] Ceramic particles (CP) serve as a hard filler in the wear-resistant layer, improving surface hardness and scratch resistance. Their high Mohs hardness, when combined with UV-cured resin, forms a multi-layered protective structure, extending the material's service life.

[0011] Nano-Titanium Dioxide Whitening Agent (NT-WA) serves as a whitening and photocatalytic functional material, enhancing the whiteness and hiding power of decorative layers. Its nanoparticle size scatters visible light and exhibits photocatalytic activity under ultraviolet light, decomposing organic pollutants and inhibiting bacterial growth, thus possessing environmentally friendly properties.

[0012] According to embodiments of the present invention, modified polyvinyl chloride resin is blended with nano-silica to form a three-dimensional network through the nano-effect of nano-silica, thereby enhancing the rigidity and impact resistance of the modified polyvinyl chloride resin. The layered structure of graphene further optimizes the stress transmission path and reduces the risk of crack propagation.

[0013] According to an embodiment of the present invention, the modified polyvinyl chloride resin is a polyvinyl chloride resin grafted with maleic anhydride; the composite heat stabilizer is a stabilizer dispersion composed of epoxidized soybean oil and calcium stearate; and the high-density oxidized polyethylene wax is a granular wax obtained by reacting polyethylene wax with oxygen at 105-120°C. The mass ratio of the polyvinyl chloride resin to the maleic anhydride is 100:1-120:1. The mass ratio of the epoxidized soybean oil to the calcium stearate is 3:1-4:1.

[0014] Composite Heat Stabilizer (CHS) inhibits the thermal decomposition of polyvinyl chloride (PVC) at high temperatures by absorbing hydrogen chloride and eliminating unstable chlorine atoms. Its multi-component synergistic effect extends the material's thermal life and maintains color stability, making it suitable for the high-temperature environment of hot pressing processes.

[0015] High-density oxidized polyethylene wax (HD-OPW) serves as a lubricant and processing aid, improving material flowability and mold release properties. Its oxidized groups can form hydrogen bonds with the resin matrix, reducing internal friction and improving surface finish, thereby lowering processing energy consumption and equipment wear.

[0016] According to embodiments of the present invention, the antioxidant properties of epoxidized soybean oil and the coordination effect of calcium stearate synergistically block the chlorine atom removal pathway, thereby extending the thermal life of the material during high-temperature processing, maintaining color stability, and taking into account both environmental protection and processing performance.

[0017] According to an embodiment of the present invention, the paraffin-based microcapsule phase change material is a micron-sized phase change microcapsule obtained by in-situ polymerization of paraffin and polyvinyl alcohol; the ultraviolet-curable resin is a solid resin obtained by copolymerizing acrylate monomers and polyurethane acrylates and then irradiating with ultraviolet light. The mass ratio of the paraffin wax to the polyvinyl alcohol is 4:1-6:1; The mass ratio of the acrylate monomer to the polyurethane acrylate is 2:1 to 4:1.

[0018] Paraffin-based microencapsulated phase change materials (P-MPCMs) utilize microencapsulation technology to encapsulate paraffin phase change materials within polymer wall materials, achieving energy storage and temperature regulation functions. They possess a high phase change enthalpy, enabling them to absorb or release heat and balance ambient temperature differences.

[0019] Ultraviolet-curable resin (UCR), used as a film-forming material for wear-resistant layers, rapidly cross-links and cures upon exposure to ultraviolet light, forming a high-hardness, high-gloss surface coating. Its active functional groups undergo polymerization under the action of a photoinitiator, enhancing wear resistance and scratch resistance.

[0020] According to embodiments of the present invention, paraffin wax serves as the core phase change material, absorbing or releasing heat through phase change to achieve temperature regulation. Polyvinyl alcohol, as the wall material, forms a dense coating layer through in-situ polymerization, effectively preventing paraffin wax leakage and enhancing the mechanical strength of the microcapsules. The two materials are combined at the molecular level interface to optimize energy transfer efficiency, achieving dynamic thermal balance of the stone-plastic flooring under temperature fluctuations.

[0021] According to an embodiment of the present invention, the ceramic particles are modified particles obtained by grinding alumina to particles with a particle size of 0.1-0.3 mm and then surface-modifying them with a silane coupling agent; the polyvinyl chloride film is a transparent film obtained by blending polyvinyl chloride resin and talc powder and then pressing it into sheets using a four-roll calender. The mass ratio of the alumina to the silane coupling agent is 20:1-20:3; The mass ratio of the polyvinyl chloride resin to the talc is 90:5-95:10.

[0022] Polyvinyl chloride base film (PVC-BF) serves as a carrier for both decorative and substrate layers, providing continuity and adhesion. Its flexible base film can be adapted to different thicknesses and can support patterns through printing or lamination processes.

[0023] According to embodiments of the present invention, by precisely controlling the mass ratio of alumina and silane coupling agent, ceramic particles form a composite structure in the substrate that combines rigidity and flexibility, maintaining surface hardness and wear resistance while avoiding stress concentration problems caused by particle aggregation. Through molecular-level interface modification to optimize mechanical properties, stone-plastic flooring achieves both high strength and durability in complex usage environments.

[0024] According to a second aspect of the present invention, a method for hot-pressing multilayer composite molding of stone-plastic flooring is provided, such as... Figure 1 As shown, it includes the following steps: S1: The ceramic particles are mixed with the ultraviolet-curable resin and then coated onto the surface of the polyvinyl chloride film to prepare a wear-resistant layer; S2: The polyvinyl chloride film is combined with the nano-titanium dioxide whitening agent to prepare a decorative layer; S3: Mix the modified polyvinyl chloride resin, nano-silica, graphene and the composite heat stabilizer to prepare a substrate layer; S4: Melt-composite the high-density oxidized polyethylene wax and the paraffin-based microcapsule phase change material to prepare the bottom layer; S5: The bottom layer, the substrate layer, the decorative layer and the wear-resistant layer are sequentially stacked to prepare a four-layer composite structure; S6: The four-layer composite structure is subjected to three-stage gradient hot pressing and intermittent pulse pressing in sequence to prepare a hot-pressed molding material; S7: Post-process the hot-pressed material to prepare multi-layer composite hot-pressed stone-plastic flooring.

[0025] According to an embodiment of the present invention, the step of combining the polyvinyl chloride film with the nano-titanium dioxide brightener to prepare the decorative layer includes: After printing the nano-titanium dioxide whitening agent on the surface of the polyvinyl chloride film, it is dried with hot air at 80-90°C for 5-8 minutes to obtain the decorative layer with a thickness of 0.2-0.5 mm.

[0026] According to embodiments of the present invention, the decorative layer formed by combining polyvinyl chloride film with nano titanium dioxide brightener not only meets the visual requirements of high gloss and high whiteness, but also enhances wear resistance and weather resistance through interfacial thermosetting, thus achieving synergistic optimization of functionality and decoration.

[0027] According to an embodiment of the present invention, the step of sequentially stacking the bottom layer, the substrate layer, the decorative layer, and the wear-resistant layer to prepare a four-layer composite structure includes: After coating the surface of the bottom layer with vinyl acetate copolymer hot melt adhesive, the substrate layer is superimposed and hot-pressed at 120-130℃ and 0.5-1.0MPa to obtain a two-layer composite structure. A polyurethane adhesive with a solid content of 40-50% is roller-coated onto the surface of the substrate layer in the two-layer composite structure. After preheating at 60-80℃, the decorative layer is superimposed to obtain a three-layer composite structure. The wear-resistant layer is coated onto the surface of the decorative layer in the three-layer composite structure at a speed of 10-15 m / min using a slot coater, with a coating accuracy of ±0.02 mm and an interlayer misalignment error of ≤0.5 mm, to obtain the four-layer composite structure.

[0028] According to an embodiment of the present invention, the coating amount of the vinyl acetate copolymer hot melt adhesive is 8-10 g / m², and the coating amount of the polyurethane adhesive is 5-8 g / m².

[0029] According to an embodiment of the present invention, the three-stage gradient hot pressing and intermittent pulse pressurization include: The three-stage gradient hot pressing includes: First stage: Temperature 160-170℃, pressure 5-6MPa, 8-10 minutes, interlayer temperature uniformity deviation ≤2℃; Second stage: Temperature 170-180℃, pressure 7-8MPa, 5-7 minutes, pressure fluctuation ≤0.3MPa; Third stage: 180℃, 8MPa, constant pressure for 2-3 minutes, hot press plate parallelism error ≤0.05mm; The intermittent pulse pressurization includes: applying a ±1MPa square wave pulse pressure at a frequency of 2Hz during the 3rd to 5th minute of the second stage, with a pulse waveform rise time ≤0.1 seconds and a sensor sampling frequency ≥200Hz.

[0030] According to an embodiment of the present invention, three-stage gradient hot pressing ensures uniform curing of the substrate and functional layer, while intermittent pulse pressurization enhances interlayer molecular diffusion through periodic stress disturbance, ultimately achieving high bonding strength, low defect rate, and precise control of complex process parameters in the multilayer composite structure.

[0031] According to an embodiment of the present invention, the post-processing of the hot-pressed material to prepare a multi-layer composite hot-pressed stone-plastic floor includes: The hot-pressed material is cooled at a rate of 5°C / min to 120°C to release the pressure, and then subjected to circulating water cooling at a water temperature of 5-10°C and a flow rate of 3-5 m / s for 30-50 minutes to obtain a cooled and shaped material. The wear-resistant layer in the cooling and shaping material is subjected to secondary curing by ultraviolet irradiation using a 120-150W / cm² mercury lamp at a distance of 10-15cm and an energy density of 5-8J / cm², resulting in the multi-layer composite hot-pressed stone-plastic flooring.

[0032] According to an embodiment of the present invention, the multi-layer composite hot-pressed stone-plastic flooring has a scratch resistance ≥10N / mm² and a heat shrinkage rate ≤0.05%.

[0033] The present invention has the following beneficial effects: This invention significantly enhances the mechanical properties and environmental adaptability of stone-plastic flooring through the synergistic effect of multiple functional materials. Modified polyvinyl chloride resin serves as the core substrate, combined with a reinforcing network structure formed by nano-silica and graphene, effectively improving the material's impact resistance and surface hardness. The synergistic effect of composite heat stabilizers and high-density oxidized polyethylene wax solves the problem of thermal degradation during high-temperature processing and improves the flowability and demolding performance during molding. Optimized interfaces and gradient distribution among the components enable the stone-plastic flooring to possess high strength, wear resistance, and long-term stability in complex environments.

[0034] This invention achieves multifunctional integration of stone-plastic flooring by introducing paraffin-based microcapsule phase change materials and ceramic particles. The paraffin-based microcapsules balance temperature fluctuations through phase change energy storage, improving the material's thermal adaptability. The ceramic particles enhance the scratch resistance of the wear-resistant layer through surface modification. The combination of UV-curable resin and nano-titanium dioxide brightener not only imparts high gloss and excellent whiteness to the decorative layer but also achieves self-cleaning functionality through photocatalysis.

[0035] This invention utilizes environmentally friendly raw materials and low-energy-consumption processes, significantly reducing the burden on the environment. The composite heat stabilizer uses epoxidized soybean oil and calcium stearate instead of traditional metal salts, avoiding the release of toxic substances. The in-situ polymerization process of paraffin-based microcapsule phase change materials and polyvinyl alcohol achieves resource recycling. Furthermore, the optimization of gradient hot pressing and intermittent pulse pressurization technologies reduces energy consumption and shortens the production cycle, while precise pressure control reduces material waste, aligning with the overall concept of sustainable development.

[0036] This invention significantly improves the molding accuracy and interfacial bonding strength of multilayer composite structures through the coordinated control of three-stage gradient hot pressing and intermittent pulsed pressurization. The gradient heating strategy ensures uniform curing of each layer, while the application of dynamic pulsed pressure promotes resin flow and bubble removal, eliminating internal defects. Combined with high-precision sensors and a real-time feedback system, dynamic optimization of process parameters is achieved, ultimately resulting in high-performance stone-plastic flooring with uniform thickness and minimal interlayer misalignment error, meeting high-end customized needs.

[0037] This invention significantly enhances the market adaptability of stone-plastic flooring through material design. The gradient cooling and UV secondary curing processes in the post-processing stage ensure the material maintains dimensional stability and surface integrity under complex temperature and humidity conditions. The precise adaptation of each functional layer in the multi-layered composite structure allows the product to meet the high-intensity usage requirements of commercial spaces while also considering the comfort and aesthetics of residential environments, providing a novel, performance- and cost-effective solution for the building decoration field.

[0038] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0039] Figure 1 This is a flowchart of a method according to an embodiment of the present invention. Detailed Implementation

[0040] This application provides a method for hot-pressing and molding multilayer composite stone-plastic flooring.

[0041] Example 1: Standard Formula Stone Plastic Flooring Modified polyvinyl chloride resin: 110 parts; Nano-silica: 12.5 parts; Graphene: 1 part; Composite heat stabilizer: 6.5 parts; High-density oxidized polyethylene wax: 10 parts; Paraffin-based microcapsule phase change material: 4 parts; UV-curable resin: 17.5 parts; Ceramic granules: 5 parts; Polyvinyl chloride film: 22.5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0042] Example 2: Increasing the graphene content Modified polyvinyl chloride resin: 110 parts; Nano-silica: 11 parts; Graphene: 1.5 parts; Composite heat stabilizer: 6.5 parts; High-density oxidized polyethylene wax: 10 parts; Paraffin-based microcapsule phase change material: 4 parts; UV-curable resin: 16 parts; Ceramic granules: 5 parts; Polyvinyl chloride film: 22.5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0043] Example 3: Reducing the content of composite heat stabilizer Modified polyvinyl chloride resin: 110 parts; Nano-silica: 12.5 parts; Graphene: 1 part; Composite heat stabilizer: 4 parts; High-density oxidized polyethylene wax: 12 parts; Paraffin-based microcapsule phase change material: 5 parts; UV-curable resin: 17.5 parts; Ceramic granules: 5 parts; Polyvinyl chloride film: 22.5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0044] Example 4: Enhanced wear resistance Modified polyvinyl chloride resin: 110 parts; Nano silica: 15 parts; Graphene: 1 part; Composite heat stabilizer: 6.5 parts; High-density oxidized polyethylene wax: 10 parts; Paraffin-based microcapsule phase change material: 4 parts; UV-curable resin: 20 parts; Ceramic granules: 6 parts; Polyvinyl chloride film: 22.5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0045] Example 5: Optimizing thermal stability Modified polyvinyl chloride resin: 110 parts; Nano-silica: 12.5 parts; Graphene: 1 part; Composite heat stabilizer: 8 parts; High-density oxidized polyethylene wax: 12 parts; Paraffin-based microcapsule phase change material: 5 parts; UV-curable resin: 17.5 parts; Ceramic granules: 5 parts; Polyvinyl chloride film: 22.5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0046] Example 6: Improving Surface Hardness Modified polyvinyl chloride resin: 110 parts; Nano silica: 15 parts; Graphene: 1.5 parts; Composite heat stabilizer: 6.5 parts; High-density oxidized polyethylene wax: 10 parts; Paraffin-based microcapsule phase change material: 4 parts; UV-curable resin: 20 parts; Ceramic granules: 5 parts; Polyvinyl chloride film: 22.5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0047] Comparative Example 1: Paraffin-free microcapsule phase change materials Modified polyvinyl chloride resin: 110 parts; Nano-silica: 12.5 parts; Graphene: 1 part; Composite heat stabilizer: 6.5 parts; High-density oxidized polyethylene wax: 10 parts; UV-curable resin: 17.5 parts; Ceramic granules: 5 parts; Polyvinyl chloride film: 22.5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0048] Comparative Example 2: Graphene-free Modified polyvinyl chloride resin: 110 parts; Nano-silica: 12.5 parts; Composite heat stabilizer: 6.5 parts; High-density oxidized polyethylene wax: 10 parts; Paraffin-based microcapsule phase change material: 4 parts; UV-curable resin: 17.5 parts; Ceramic granules: 5 parts; Polyvinyl chloride film: 22.5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0049] Comparative Example 3: UV-free curable resin Modified polyvinyl chloride resin: 110 parts; Nano-silica: 12.5 parts; Graphene: 1 part; Composite heat stabilizer: 6.5 parts; High-density oxidized polyethylene wax: 10 parts; Paraffin-based microcapsule phase change material: 4 parts; Ceramic granules: 5 parts; Polyvinyl chloride film: 22.5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0050] Comparative Example 4: Polyvinyl chloride film Modified polyvinyl chloride resin: 110 parts; Nano-silica: 12.5 parts; Graphene: 1 part; Composite heat stabilizer: 6.5 parts; High-density oxidized polyethylene wax: 10 parts; Paraffin-based microcapsule phase change material: 4 parts; UV-curable resin: 17.5 parts; Ceramic granules: 5 parts; Nano titanium dioxide whitening agent: 2 parts.

[0051] Experimental example: The performance was measured based on Examples 1-6 and Comparative Examples 1-4 above, and the results are shown in Table 1. These include: 1. Abrasion resistance test The wear tester (CS-17 wheel) was used to record the wear mass loss of the samples with a load of 500g and a rotation speed of 1000 rpm.

[0052] 2. Thermal stability test The thermal decomposition initiation temperature of the sample under nitrogen atmosphere was determined by thermogravimetric analysis.

[0053] 3. Surface hardness test The scratch resistance of the wear-resistant layer (H-9H grade) was tested using the pencil hardness scratch test.

[0054] 4. Phase Change Energy Storage Efficiency Test The phase transition enthalpy of paraffin-based microcapsule phase change materials was determined using differential scanning calorimetry.

[0055] 5. Environmental performance testing The formaldehyde release was determined using a volatile organic compound detector.

[0056] 6. Mechanical strength test The tensile strength and elongation at break of the material were tested using a tensile testing machine at a speed of 5 mm / min. The maximum tensile force and the elongation at break were recorded.

[0057] Table 1. Experimental data of Examples 1-6 and Comparative Examples 1-4 of the present invention

[0058] As shown in Table 1, the wear resistance is: The wear mass loss in Example 2 (increased graphene content) and Example 4 (enhanced wear resistance) was significantly reduced, at 0.06 g and 0.04 g respectively, indicating that the synergistic effect of graphene and ceramic particles can effectively improve wear resistance. Comparative Example 2 (without graphene) showed the highest wear mass loss of 0.15g due to the lack of hard filler support, verifying the necessity of graphene for wear resistance.

[0059] Thermal stability: Example 5 (optimized thermal stability) showed the highest thermal decomposition onset temperature of 290°C, thanks to the combined optimization of paraffin-based microcapsule phase change material and composite thermal stabilizer. Example 3 (reduced composite heat stabilizer) showed a decrease in thermal stability, while Comparative Example 2 (no graphene) showed a further decrease to 250°C due to its loose structure, indicating that the heat stabilizer and graphene work together to ensure high-temperature performance.

[0060] Surface hardness: Example 6 (improved surface hardness) achieved a 9H rating, attributed to the synergistic enhancement of nano-silica and UV-curable resin; Example 4 also achieved an 8H rating due to the increased content of ceramic particles. Comparative Example 3 (without UV-cured resin) has a hardness of only 5H, indicating that its film-forming material plays a decisive role in the hardness of the wear-resistant layer.

[0061] Phase change energy storage efficiency: Comparative Example 1 (without paraffin-based microcapsule phase change material) has a phase change enthalpy of 0, directly proving that its temperature control function is lacking; Example 5 further enhances the energy storage capacity by increasing the content of phase change material to 255 kJ / kg.

[0062] Environmental performance: Example 6 (improved surface hardness) had the lowest formaldehyde release due to reduced organic solvent usage; Comparative Example 2 (no graphene) had the highest release of 0.06 mg / m³ due to unstable material structure.

[0063] Mechanical strength: Example 6 (improved surface hardness) showed the highest tensile strength, attributed to the synergistic enhancement of nano-silica and UV-curable resin; Example 4 also showed an increase to 50 MPa due to the combined effect of ceramic particles and UV-curable resin. Comparative Example 2 (without graphene) had the lowest tensile strength of 30 MPa, indicating that graphene provides significant mechanical support to the overall structure.

[0064] Based on the integrated experimental data, multi-layer composite hot-pressed stone-plastic flooring exhibits excellent wear resistance, thermal stability, surface hardness, phase change energy storage efficiency, environmental performance, and mechanical strength. It is suitable for architectural decoration, commercial spaces, and outdoor projects, performing particularly well in high-humidity and high-temperature environments. Future development can further optimize the proportion of nanomaterials and phase change material encapsulation technology to expand its applications in green building materials and energy-saving buildings, thereby promoting the industrialization of high-performance environmentally friendly materials.

[0065] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0066] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A multi-layer composite hot-pressed stone-plastic flooring, characterized in that, The stone-plastic flooring is composed of the following components in parts by weight: Modified polyvinyl chloride resin: 100-120 parts; Nano silica: 10-15 parts; Graphene: 0.5–1.5 parts; Composite heat stabilizer: 5-8 parts; High-density oxidized polyethylene wax: 8-12 parts; Paraffin-based microcapsule phase change material: 3-5 parts; UV-curable resin: 15-20 parts; Ceramic particles: 4-6 parts; Polyvinyl chloride film: 20-25 parts; Nano titanium dioxide whitening agent: 1-3 parts.

2. The stone-plastic flooring according to claim 1, characterized in that: The modified polyvinyl chloride resin is a polyvinyl chloride resin grafted with maleic anhydride; the composite heat stabilizer is a stabilizer dispersion composed of epoxidized soybean oil and calcium stearate; the high-density oxidized polyethylene wax is a granular wax obtained by reacting polyethylene wax with oxygen at 105-120℃. The mass ratio of the polyvinyl chloride resin to the maleic anhydride is 100:1-120:

1. The mass ratio of the epoxidized soybean oil to the calcium stearate is 3:1-4:

1.

3. The stone-plastic flooring according to claim 1, characterized in that: The paraffin-based microcapsule phase change material is a micron-sized phase change microcapsule obtained by in-situ polymerization of paraffin and polyvinyl alcohol; the ultraviolet-cured resin is a solid resin obtained by copolymerizing acrylate monomers and polyurethane acrylates and then irradiating with ultraviolet light. The mass ratio of the paraffin wax to the polyvinyl alcohol is 4:1-6:1; The mass ratio of the acrylate monomer to the polyurethane acrylate is 2:1 to 4:

1.

4. The stone-plastic flooring according to claim 1, characterized in that: The ceramic particles are modified particles obtained by grinding alumina to a particle size of 0.1-0.3 mm and then surface-modifying them with a silane coupling agent; the polyvinyl chloride film is a transparent film obtained by blending polyvinyl chloride resin and talc powder and then pressing it into sheets using a four-roll calender. The mass ratio of the alumina to the silane coupling agent is 20:1-20:3; The mass ratio of the polyvinyl chloride resin to the talc is 90:5-95:

10.

5. A method for hot-pressing multilayer composite stone-plastic flooring as described in any one of claims 1-4, characterized in that: The steps include: The ceramic particles are mixed with the ultraviolet-curable resin and then coated onto the surface of the polyvinyl chloride film to prepare a wear-resistant layer. A decorative layer is prepared by combining the polyvinyl chloride film with the nano-titanium dioxide whitening agent. The modified polyvinyl chloride resin, nano-silica, graphene, and the composite heat stabilizer are mixed to prepare the substrate layer; The high-density oxidized polyethylene wax and the paraffin-based microcapsule phase change material are melt-composite to prepare the bottom layer; A four-layer composite structure is prepared by sequentially stacking the bottom layer, the substrate layer, the decorative layer, and the wear-resistant layer; The four-layer composite structure was subjected to three-stage gradient hot pressing and intermittent pulse pressing in sequence to prepare a hot-pressed material. The hot-pressed material is post-processed to prepare a multi-layer composite hot-pressed stone-plastic floor.

6. The multi-layer composite hot-pressing molding method for stone-plastic flooring according to claim 5, characterized in that: The step of combining the polyvinyl chloride film with the nano-titanium dioxide brightener to prepare the decorative layer includes: After printing the nano-titanium dioxide whitening agent on the surface of the polyvinyl chloride film, it is dried with hot air at 80-90°C for 5-8 minutes to obtain the decorative layer with a thickness of 0.2-0.5 mm.

7. The multi-layer composite hot-pressing molding method for stone-plastic flooring according to claim 5, characterized in that: The step of sequentially stacking the bottom layer, the substrate layer, the decorative layer, and the wear-resistant layer to prepare a four-layer composite structure includes: After coating the surface of the bottom layer with vinyl acetate copolymer hot melt adhesive, the substrate layer is superimposed and hot-pressed at 120-130℃ and 0.5-1.0MPa to obtain a two-layer composite structure. A polyurethane adhesive with a solid content of 40-50% is roller-coated onto the surface of the substrate layer in the two-layer composite structure. After preheating at 60-80℃, the decorative layer is superimposed to obtain a three-layer composite structure. The wear-resistant layer is coated onto the surface of the decorative layer in the three-layer composite structure at a speed of 10-15 m / min using a slot coater, with a coating accuracy of ±0.02 mm and an interlayer misalignment error of ≤0.5 mm, to obtain the four-layer composite structure.

8. The multi-layer composite hot-pressing molding method for stone-plastic flooring according to claim 5, characterized in that: The three-stage gradient hot pressing and intermittent pulse pressurization include: The three-stage gradient hot pressing includes: First stage: Temperature 160-170℃, pressure 5-6MPa, 8-10 minutes, interlayer temperature uniformity deviation ≤2℃; Second stage: Temperature 170-180℃, pressure 7-8MPa, 5-7 minutes, pressure fluctuation ≤0.3MPa; Third stage: 180℃, 8MPa, constant pressure for 2-3 minutes, hot press plate parallelism error ≤0.05mm; The intermittent pulse pressurization includes: applying a ±1MPa square wave pulse pressure at a frequency of 2Hz during the 3rd to 5th minute of the second stage, with a pulse waveform rise time ≤0.1 seconds and a sensor sampling frequency ≥200Hz.

9. The multi-layer composite hot-pressing molding method for stone-plastic flooring according to claim 5, characterized in that: The post-processing of the hot-pressed material to prepare multi-layer composite hot-pressed stone-plastic flooring includes: The hot-pressed material is cooled at a rate of 5°C / min to 120°C to release the pressure, and then subjected to circulating water cooling at a water temperature of 5-10°C and a flow rate of 3-5 m / s for 30-50 minutes to obtain a cooled and shaped material. The wear-resistant layer in the cooling and shaping material is subjected to secondary curing by ultraviolet irradiation using a 120-150W / cm² mercury lamp at a distance of 10-15cm and an energy density of 5-8J / cm², resulting in the multi-layer composite hot-pressed stone-plastic flooring.

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