Flame-retardant stone plastic floor and preparation method thereof

Abstract

The present application relates to stone plastic floor technology field, especially relates to a kind of flame-retardant stone plastic floor and preparation method thereof, including base layer, intermediate layer, surface layer and cladding layer, the intermediate layer is between base layer and surface layer, the cladding layer is wrapped in the outside of base layer, intermediate layer and surface layer;The base layer includes polyvinyl chloride resin 60-70 parts, calcium carbonate powder 200-250 parts, stabilizer 3-5 parts, lubricant 1-2 parts;In the present application, different flame-retardant functions can be played by the layering design of each layer of floor, form synergistic flame-retardant system, the flame retardant of surface layer can first play a role when flame contact, slow down the flame spread speed, the aluminum hydroxide flame retardant of intermediate layer is decomposed to absorb a lot of heat, and release water vapor, dilute oxygen concentration, prevent the continuous combustion, the flame retardant of outer cladding layer ammonium polyphosphate further blocks flame, this layered flame-retardant design can effectively improve the flame-retardant effect of floor, greatly reduce the risk of fire.

Description

Technical Field

[0001] This invention relates to the field of stone-plastic flooring technology, and in particular to a flame-retardant stone-plastic flooring and its preparation method. Background Technology

[0002] With the continuous development of the building decoration industry, people's requirements for flooring materials are increasing. Among the many types of flooring, stone plastic flooring has received widespread attention due to its aesthetic appeal, economy, and ease of installation. However, traditional stone plastic flooring has significant shortcomings in flame retardant performance and can easily become a medium for the spread of fire in the event of a fire, posing a serious threat to life and property safety.

[0003] In densely populated places such as shopping malls, hotels, schools and residences, the flame retardancy of flooring materials is crucial. In the event of a fire, the flames, smoke and toxic gases produced by burning ordinary flooring will not only accelerate the spread of the fire, but also hinder the evacuation of people and increase the risk of injury and death. Therefore, developing stone plastic flooring with excellent flame retardant properties has become an urgent problem to be solved in the industry.

[0004] Meanwhile, during the long-term use of flooring, its wear resistance and UV resistance also need to be considered. Frequent foot traffic and furniture dragging can cause wear and tear on the floor surface, affecting its appearance and lifespan. In areas with good indoor lighting or direct sunlight, UV radiation can easily cause the flooring material to age and discolor, reducing its decorative effect and durability.

[0005] Therefore, this invention proposes a flame-retardant stone-plastic flooring and its preparation method. Through a layered design, each layer of the flooring can perform different flame-retardant functions, forming a synergistic flame-retardant system. The flame retardant in the surface layer can act first when in contact with flames, slowing down the spread of flames. The aluminum hydroxide flame retardant in the middle layer decomposes upon heating, absorbing a large amount of heat and releasing water vapor, diluting the oxygen concentration and preventing the continuation of combustion. The ammonium polyphosphate flame retardant in the outer wrapping layer further blocks the flame. This layered flame-retardant design can effectively improve the flame-retardant effect of the flooring and greatly reduce the risk of fire. Summary of the Invention

[0006] Technical problems solved: poor flame retardancy and easy wear of traditional stone-plastic flooring.

[0007] To address the shortcomings of existing technologies, this invention provides a flame-retardant stone-plastic flooring and its preparation method, thereby solving the technical problems mentioned in the background section.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] In a first aspect, the present invention proposes a flame-retardant stone-plastic flooring, the flooring comprising a base layer, an intermediate layer, a surface layer and a covering layer, wherein the intermediate layer is placed between the base layer and the surface layer, and the covering layer is wrapped around the base layer, the intermediate layer and the surface layer.

[0010] The base layer comprises 60-70 parts of polyvinyl chloride resin, 200-250 parts of calcium carbonate powder, 3-5 parts of stabilizer, and 1-2 parts of lubricant;

[0011] The intermediate layer comprises 70-80 parts of amorphous copolyester and 20-30 parts of aluminum hydroxide flame retardant;

[0012] The surface layer comprises 70-80 parts of polyvinyl chloride resin, 10-15 parts of alumina wear-resistant agent, 5-8 parts of flame retardant, 1-2 parts of UV stabilizer, and 3-5 parts of stabilizer.

[0013] The coating layer comprises 70-80 parts of thermoplastic polyurethane elastomer rubber and 20-30 parts of ammonium polyphosphate.

[0014] In one possible implementation, the stabilizer is a calcium-zinc stabilizer, the lubricant is stearic acid, the flame retardant is antimony trioxide, and the UV stabilizer is a benzotriazole.

[0015] Secondly, this invention proposes a method for preparing flame-retardant stone-plastic flooring, applicable to the preparation of the aforementioned flame-retardant stone-plastic flooring, comprising the following steps:

[0016] Step 1, Base layer preparation:

[0017] Mix PVC resin, calcium carbonate powder, stabilizer, lubricant and additives in a high-speed mixer at a speed of 800-1000 rpm for 10-15 minutes according to the above ratio to ensure that the materials are mixed evenly.

[0018] Add the mixed materials into a single-screw or twin-screw extruder. Set the temperature of each section of the extruder to 150-160℃, 160-170℃, and 170-180℃ respectively. Control the screw speed at 30-50 rpm. Extrude into sheets with a thickness of about 2-3mm. Then cool and shape them, and cut them into appropriate sizes for later use.

[0019] Step 2, Preparation of the intermediate layer:

[0020] PETG granules and aluminum hydroxide flame retardant are dried in a vacuum drying oven at 80-90℃ for 4-6 hours, and then melt-blended and extruded in a twin-screw extruder. The temperatures of each section of the extruder are set to 200-210℃, 210-220℃, and 220-230℃, and the screw speed is 200-300 rpm. Sheets with a thickness of about 1-2 mm are produced, cooled, and cut into appropriate sizes for later use.

[0021] Step 3, Surface preparation:

[0022] Mix PVC resin, alumina wear-resistant agent, flame retardant, UV stabilizer, and stabilizer additives in a high-speed mixer at a speed of 800-1000 rpm for 10-15 minutes according to the specified ratio to ensure uniform mixing.

[0023] The mixed materials are extruded into sheets in an extruder. The extruder temperature is set to 160-170℃, 170-180℃, and 180-190℃, the screw speed is 40-60 rpm, and the sheet thickness is about 0.5-1mm. The sheets are then cooled, shaped, and cut into appropriate sizes for later use.

[0024] Step 4, Preparation of the coating layer:

[0025] Dry the TPU particles in a vacuum drying oven at 80-90℃ for 4-6 hours;

[0026] Mix the dried TPU granules and ammonium polyphosphate powder thoroughly in a high-speed mixer according to the specified ratio. The mixing time is about 10-15 minutes, and the speed is controlled at 800-1200 rpm.

[0027] The mixed materials are added to a twin-screw extruder for melt blending, extrusion, and granulation. The extrusion temperature is set at 180-220℃ and the screw speed is 200-300 rpm to obtain TPU / APP composite material particles.

[0028] TPU / APP composite particles are processed into films with a thickness of approximately 0.2-0.5 mm using casting or blow molding processes for later use.

[0029] Step 5: Floor Forming

[0030] After the prepared base layer, intermediate layer and surface layer are stacked in sequence, preliminary hot pressing composite is carried out on a hot press. The hot pressing conditions are 120-150℃ temperature, 3-5MPa pressure and 2-3 minutes to make the three layers tightly bonded.

[0031] The prepared TPU / APP film is covered on the surface of the pre-composite board, and then hot-pressed again at 130-160℃ and 4-6MPa for 3-5 minutes to firmly cover the outside of the floor and form a decorative and anti-slip pattern, finally obtaining the flame-retardant stone plastic flooring.

[0032] Beneficial effects compared to existing technologies:

[0033] 1. In this solution, the layered design allows each layer of the floor to perform different flame-retardant functions, forming a synergistic flame-retardant system. The flame retardant on the surface layer can take effect first when in contact with flames, slowing down the spread of flames. The aluminum hydroxide flame retardant in the middle layer decomposes when heated, absorbing a large amount of heat and releasing water vapor, which dilutes the oxygen concentration and prevents the continued combustion. The ammonium polyphosphate flame retardant in the outer wrapping layer further blocks the flames. This layered flame-retardant design can effectively improve the flame-retardant effect of the floor and greatly reduce the risk of fire.

[0034] 2. In this solution, the addition of PETG material helps to evenly disperse the aluminum hydroxide flame retardant, allowing the flame retardant to function better. At the same time, PETG itself has a certain ability to block heat transfer, forming a heat insulation barrier during the flame spread process to prevent heat from being transferred to other layers, thereby enhancing the flame retardant performance of the entire floor and enabling the floor to better meet fire safety requirements. Attached Figure Description

[0035] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0036] Figure 1 This is a schematic diagram of the overall structure of a flame-retardant stone-plastic flooring.

[0037] Figure 2 This is a process flow diagram for the preparation of a flame-retardant stone-plastic flooring. Detailed Implementation

[0038] Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can also be implemented in various different forms, and therefore the present invention is not limited to the embodiments described below.

[0039] The technical solution in this application embodiment is to solve the problems mentioned in the background art, and the overall idea is as follows:

[0040] Example 1:

[0041] Please refer to Figures 1-2 As shown, this embodiment introduces a flame-retardant stone-plastic flooring, including a base layer 1, an intermediate layer 2, a surface layer 3, and a covering layer 4. The intermediate layer 2 is placed between the base layer 1 and the surface layer 3, and the covering layer 4 is wrapped around the outside of the base layer 1, the intermediate layer 2, and the surface layer 3.

[0042] The base layer 3 provides structural support, giving the floor a certain degree of resistance to deformation. The middle layer 2 prevents heat transfer, forming a flame-retardant barrier and enhancing the overall flame-retardant performance of the floor. The top layer 1 provides wear resistance and protection, enabling the floor surface to withstand frequent foot traffic and furniture movement, reducing surface wear and maintaining the durability of the floor's appearance. The covering layer 4 provides protection and decoration, protecting the inner base layer 1, middle layer 2, and top layer 3 from external environmental erosion, such as preventing the intrusion of moisture and oil. Through hot-pressing pattern treatment, the covering layer 4 can form decorative and anti-slip patterns, allowing the floor to meet safety requirements while also having a good appearance, increasing the practicality and aesthetics of the floor.

[0043] Example 2:

[0044] This invention provides a flame-retardant stone-plastic flooring, comprising the following raw materials in parts by weight:

[0045] Base layer: 65 parts polyvinyl chloride (PVC) resin, 230 parts calcium carbonate powder, 4 parts calcium zinc stabilizer, and 1.5 parts stearic acid;

[0046] Intermediate layer: 75 parts of amorphous copolyester (PETG), 25 parts of aluminum hydroxide (ATH) flame retardant;

[0047] Surface layer: 75 parts polyvinyl chloride (PVC) resin, 12 parts alumina abrasion retardant, 6 parts antimony trioxide flame retardant, 1.5 parts benzotriazole UV stabilizer, and 4 parts stabilizer.

[0048] Encapsulation layer: 75 parts thermoplastic polyurethane elastomer rubber (TPU), 25 parts ammonium polyphosphate (APP);

[0049] This embodiment provides a flame-retardant stone-plastic flooring prepared by the following steps:

[0050] 1. Base layer preparation: Mix PVC resin, calcium carbonate powder, stabilizer, lubricant and additives in a high-speed mixer at 900 rpm for 12 minutes according to the above ratio to ensure uniform mixing. Add the mixed material to a twin-screw extruder. Set the temperature of each section of the extruder to 155℃, 165℃ and 175℃ respectively, and control the screw speed at 40 rpm. Extrude into sheets with a thickness of about 2.5mm, then cool and shape them, and cut them into appropriate sizes for later use.

[0051] 2. Preparation of intermediate layer: After drying PETG granules and aluminum hydroxide flame retardant in a vacuum drying oven at 85°C for 5 hours, they are melt-blended and extruded in a twin-screw extruder. The temperatures of each section of the extruder are set to 205°C, 215°C, and 225°C, and the screw speed is 250 rpm. A sheet with a thickness of about 1.5 mm is produced, cooled, and cut into appropriate sizes for later use.

[0052] 3. Surface preparation: PVC resin, alumina wear-resistant agent, flame retardant, UV stabilizer, and stabilizer additives are mixed in a high-speed mixer at 900 rpm for 12 minutes according to the specified ratio to ensure uniform mixing. The mixed material is then extruded into sheets in an extruder. The extruder temperature is set to 165℃, 175℃, and 185℃, the screw speed is 50 rpm, and the sheet thickness is approximately 0.8 mm. The sheets are then cooled, shaped, and cut into appropriate sizes for later use.

[0053] 4. Coating layer preparation: TPU granules are dried in a vacuum drying oven at 85°C for 5 hours. The dried TPU granules and ammonium polyphosphate powder are then thoroughly mixed in a high-speed mixer according to the specified ratio. The mixing time is approximately 12 minutes, and the speed is controlled at 1000 rpm. The mixed material is then added to a twin-screw extruder for melt blending and extrusion granulation. The extrusion temperature is set at 200°C, and the screw speed is 250 rpm to obtain TPU / APP composite material granules. The TPU / APP composite material granules are then processed into a film with a thickness of approximately 0.3 mm using a casting process for later use.

[0054] 5. Floor molding

[0055] After the prepared base layer, intermediate layer and surface layer are stacked in sequence, they are initially hot-pressed on a hot press. The hot pressing conditions are 135℃, 4MPa and 2.5 minutes to make the three layers tightly bonded.

[0056] The prepared TPU / APP film is covered on the surface of the pre-composite board, and then hot-pressed again at 145℃ and 5MPa for 4 minutes to firmly cover the outside of the floor and form a decorative and anti-slip pattern, finally obtaining the flame-retardant stone plastic flooring.

[0057] Comparative Example 1:

[0058] This invention provides a flame-retardant stone-plastic flooring, comprising the following raw materials in parts by weight:

[0059] Overall Mixture: Mix 70 parts of amorphous copolyester (PETG), 65 parts of polyvinyl chloride (PVC) resin (approximately based on the combined amount of base and surface layers), 200 parts of calcium carbonate powder (approximately based on the base layer amount), 20 parts of aluminum hydroxide (ATH) flame retardant, 8 parts of alumina abrasion resistant agent (approximately based on the surface layer amount), 4 parts of flame retardant (e.g., antimony trioxide, approximately based on the surface layer amount), 1 part of UV stabilizer (e.g., benzotriazole, approximately based on the surface layer amount), 4 parts of stabilizer (approximately based on the combined amount of base and surface layers), 1 part of lubricant (e.g., stearic acid, approximately based on the base layer amount), and 20 parts of ammonium polyphosphate (APP).

[0060] This embodiment provides a flame-retardant stone-plastic flooring prepared by the following steps:

[0061] Mix all the above materials in a high-speed mixer at a speed of 800-1000 rpm for 10-15 minutes according to the proportions to ensure that the materials are mixed evenly.

[0062] The mixed materials are added to a single-screw or twin-screw extruder. The temperature of each section of the extruder is set to 150-180℃ (combining the temperature range of the base layer, intermediate layer, and surface layer extruders). The screw speed is controlled at 30-60 rpm (combining the screw speed range of each layer). The material is extruded into sheets with a thickness of approximately 3-5mm (combining the thickness range of each layer). The sheets are then cooled and shaped, and cut into appropriate sizes for later use.

[0063] Comparative Example 2:

[0064] This invention provides a flame-retardant stone-plastic flooring, comprising the following raw materials in parts by weight:

[0065] Base layer: 60 parts polyvinyl chloride (PVC) resin, 200 parts calcium carbonate powder, 3 parts stabilizer (such as calcium zinc stabilizer), 1 part lubricant (such as stearic acid);

[0066] Intermediate layer: 20 parts aluminum hydroxide (ATH) flame retardant (PETG removed, only flame retardant component retained);

[0067] Surface layer: 70 parts polyvinyl chloride (PVC) resin, 10 parts alumina abrasion retardant, 5 parts flame retardant (such as antimony trioxide), 1 part UV stabilizer (such as benzotriazole), and 3 parts stabilizer.

[0068] Outer wrapping layer: 70 parts thermoplastic polyurethane elastomer rubber (TPU), 20 parts ammonium polyphosphate (APP);

[0069] This embodiment provides a flame-retardant stone-plastic flooring prepared by the following steps:

[0070] 1. Base layer preparation: Mix PVC resin, calcium carbonate powder, stabilizer, lubricant and additives in a high-speed mixer at 800-1000 rpm for 10-15 minutes according to the above ratio to ensure uniform mixing. Add the mixed material to a single-screw or twin-screw extruder. Set the temperature of each section of the extruder to 150-160℃, 160-170℃, and 170-180℃ respectively, and control the screw speed at 30-50 rpm. Extrude into sheets with a thickness of about 2-3mm, then cool and shape them, and cut them into appropriate sizes for later use.

[0071] 2. Preparation of intermediate layer: After drying the aluminum hydroxide flame retardant in a vacuum drying oven at 80-90℃ for 4-6 hours, it is melt-blended and extruded in a twin-screw extruder. The temperature of each section of the extruder is set to 200-210℃, 210-220℃, and 220-230℃, and the screw speed is 200-300 rpm. The resulting sheet is about 1-2 mm thick. After cooling, it is cut into appropriate sizes for later use.

[0072] 3. Surface preparation: Mix PVC resin, alumina wear-resistant agent, flame retardant, UV stabilizer, and stabilizer additives in a high-speed mixer at 800-1000 rpm for 10-15 minutes according to the specified ratio to ensure uniform mixing. Extrude the mixed material into sheets in an extruder. Set the extruder temperature to 160-170℃, 170-180℃, and 180-190℃, and the screw speed to 40-60 rpm. The sheet thickness should be approximately 0.5-1mm. Cool and shape the sheet, then cut it into suitable sizes for later use.

[0073] 4. Coating Layer Preparation: Dry TPU granules in a vacuum drying oven at 80-90℃ for 4-6 hours. Mix the dried TPU granules and ammonium polyphosphate powder according to the specified ratio in a high-speed mixer for approximately 10-15 minutes at a speed of 800-1200 rpm. Add the mixed material to a twin-screw extruder for melt blending and granulation. Set the extrusion temperature to 180-220℃ and the screw speed to 200-300 rpm to obtain TPU / APP composite granules. Form the TPU / APP composite granules into films with a thickness of approximately 0.2-0.5 mm using casting or blow molding processes for later use.

[0074] 5. Flooring Forming: After stacking the prepared base layer, intermediate layer, and surface layer in sequence, perform preliminary hot-pressing composite on a hot press. The hot-pressing conditions are 120-150℃, 3-5MPa, and 2-3 minutes to ensure a tight bond between the three layers. Cover the surface of the pre-composite board with the prepared TPU / APP film, and then perform hot-pressing pattern treatment again at 130-160℃ and 4-6MPa for 3-5 minutes to firmly cover the outside of the flooring and form decorative and anti-slip patterns, finally obtaining the finished product.

[0075] Comparative experiment:

[0076] Three types of flooring were prepared according to the formulations and preparation processes in Example 2, Comparative Example 1, and Comparative Example 2, respectively. The flame retardancy, abrasion resistance, UV resistance, and physical properties of these three types of flooring were tested. The specific experimental procedures and results are as follows:

[0077] 1. Flame retardant performance test

[0078] 1.1 Test Method

[0079] The limiting oxygen index (LOI) test method is used to prepare samples of a specific size. In a nitrogen-oxygen mixed gas flow, the minimum oxygen concentration required for the sample to just maintain combustion is measured. The LOI value is used as an indicator to evaluate the flame retardant performance. The higher the LOI value, the better the flame retardancy of the material.

[0080] Simultaneously observe the burning time and self-extinguishing time of the material in the flame. Ignite the sample under specified fire source conditions and record the time from ignition to flame extinguishing. The shorter the burning time and the faster the self-extinguishing time, the better the flame retardant performance.

[0081] 1.2 Test Results

[0082] Floor type LOI range Burning time (seconds) Self-extinguishing time (seconds) Example 2 35％ 10 5 Comparative Example 1 25％ 30 20 Comparative Example 2 27％ 25 15

[0083] 2. Wear resistance test

[0084] 2.1 Test Method

[0085] Using a Taber abrasion tester, a specific type of grinding wheel is rotated at a certain speed under a certain load to conduct an abrasion test on the floor surface. After a specified number of abrasion revolutions, the mass loss of the sample is measured. The abrasion resistance of the floor is evaluated by the magnitude of the mass loss; the smaller the mass loss, the better the abrasion resistance.

[0086] 2.2 Test Results

[0087] Floor type Wear rotation speed Mass loss (g) Example 2 5000 RPM 0.05 Comparative Example 1 5000 RPM 0.12 Comparative Example 2 5000 RPM 0.08

[0088] 3. UV resistance performance test

[0089] 3.1 Test Method

[0090] The flooring samples were placed in a UV aging test chamber and continuously irradiated for a certain period of time (e.g., 1000 hours) under specified UV radiation intensity, temperature, and humidity conditions. Before and after irradiation, the rate of change of the sample's color (expressed as color difference value ΔE; the smaller the ΔE, the smaller the color change and the better the UV resistance) and mechanical properties (e.g., tensile strength, flexural strength, etc.) were measured. The smaller the rate of change, the better the UV resistance.

[0091] 3.2 Test Results

[0092] Floor type Color change ΔE Tensile strength change rate Bending strength change rate Example 2 2.5 -5％ -3％ Comparative Example 1 5.0 -12％ -8％ Comparative Example 2 3.5 25 -5％

[0093] 4. Physical performance testing

[0094] 4.1 Test Method

[0095] Hardness testing was conducted using a Shore hardness tester. Multiple test points were selected on the floor surface, and their hardness values ​​were measured. The average value was taken as the hardness index of the floor.

[0096] For the bending strength test, in accordance with GB / T9341-2008 "Determination of Bending Properties of Plastics", the floor sample was made into standard size and subjected to a three-point bending test on a universal testing machine to determine its bending strength.

[0097] Dimensional stability testing involves placing floor samples in an environment with specified temperature (e.g., 80°C) and humidity (e.g., 90% RH) for a certain period of time (e.g., 24 hours) and measuring the rate of change in sample dimensions.

[0098] 4.2 Test Results

[0099]

[0100] The test data above shows that:

[0101] In terms of flame retardant performance, Example 2 exhibits the best performance due to its layered structure and reasonable material ratio. It has a higher limiting oxygen index, shorter combustion time, and shorter self-extinguishing time. The flame retardants in each layer work synergistically to effectively prevent flame spread and continued combustion. Comparative Example 1, lacking a layered structure, suffers from impaired distribution and synergistic effects of the flame retardants, resulting in a significant decrease in flame retardant performance. Comparative Example 2, lacking PETG material in the middle layer, shows a worse overall flame retardant synergistic effect. While slightly better than Comparative Example 1, it is still far inferior to Example 2, indicating that PETG, in combination with other flame retardants in the middle layer, plays a crucial role in improving the flame retardant performance of the flooring.

[0102] Regarding abrasion resistance, Example 2 exhibited the least mass loss and the best abrasion resistance. Comparative Example 1 showed the greatest mass loss and the worst abrasion resistance, possibly because its overall composite material structure was less conducive to the effectiveness of the abrasion-resistant agent compared to a layered structure. Comparative Example 2's abrasion resistance fell between the two, indicating that while PETG material does have some influence on abrasion resistance, it is not the sole determining factor.

[0103] Regarding UV resistance, Example 2 exhibited the smallest rate of color and mechanical property change, demonstrating the best UV resistance. Comparative Example 1 showed larger changes in both color and mechanical properties, indicating poorer UV resistance, possibly due to its material mixing method preventing the UV stabilizer from functioning effectively. Comparative Example 2's UV resistance was weaker than Example 2, further demonstrating the positive impact of PETG material in the interlayer on the overall performance of the flooring.

[0104] In terms of physical properties, Example 2 showed better performance in hardness, flexural strength, and dimensional stability, while Comparative Example 1 performed relatively poorly in all physical property indicators, and Comparative Example 2 fell in between. This indicates that the layered structure and PETG material also have a certain impact on the physical properties of the flooring, and a reasonable layered design and material selection can help improve the overall physical properties of the flooring.

[0105] In conclusion, in the design and preparation of flame-retardant stone plastic flooring, a reasonable layered structure and the use of the key material PETG are crucial for optimizing flame-retardant performance. These factors should be given full attention in actual production and R&D. At the same time, the actual flame-retardant performance needs to be further verified and optimized through rigorous standard testing.

[0106] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing flame-retardant stone-plastic flooring, characterized in that, The following methods and steps are included: Step 1, Base layer preparation: Mix PVC resin, calcium carbonate powder, stabilizer, lubricant and additives in a high-speed mixer at a speed of 800-1000 rpm for 10-15 minutes according to the above ratio to ensure that the materials are mixed evenly. Add the mixed materials into a single-screw or twin-screw extruder. Set the temperature of each section of the extruder to 150-160℃, 160-170℃, and 170-180℃ respectively. Control the screw speed at 30-50 rpm. Extrude into sheets with a thickness of about 2-3mm. Then cool and shape them, and cut them into appropriate sizes for later use. Step 2, Preparation of the intermediate layer: PETG granules and aluminum hydroxide flame retardant are dried in a vacuum drying oven at 80-90℃ for 4-6 hours, and then melt-blended and extruded in a twin-screw extruder. The temperatures of each section of the extruder are set to 200-210℃, 210-220℃, and 220-230℃, and the screw speed is 200-300 rpm. Sheets with a thickness of about 1-2 mm are produced, cooled, and cut into appropriate sizes for later use. Step 3, Surface preparation: Mix PVC resin, alumina wear-resistant agent, flame retardant, UV stabilizer, and stabilizer additives in a high-speed mixer at a speed of 800-1000 rpm for 10-15 minutes according to the specified ratio to ensure uniform mixing. The mixed materials are extruded into sheets in an extruder. The extruder temperature is set to 160-170℃, 170-180℃, and 180-190℃, the screw speed is 40-60 rpm, and the sheet thickness is about 0.5-1mm. The sheets are then cooled, shaped, and cut into appropriate sizes for later use. Step 4, Preparation of the coating layer: Dry the TPU particles in a vacuum drying oven at 80-90℃ for 4-6 hours; Mix the dried TPU granules and ammonium polyphosphate powder thoroughly in a high-speed mixer according to the specified ratio. The mixing time is about 10-15 minutes, and the speed is controlled at 800-1200 rpm. The mixed materials are added to a twin-screw extruder for melt blending, extrusion, and granulation. The extrusion temperature is set at 180-220℃ and the screw speed is 200-300 rpm to obtain TPU / APP composite material particles. TPU / APP composite particles are processed into films with a thickness of approximately 0.2-0.5 mm using casting or blow molding processes for later use. Step 5: Floor Forming After the prepared base layer, intermediate layer and surface layer are stacked in sequence, preliminary hot pressing composite is carried out on a hot press. The hot pressing conditions are 120-150℃ temperature, 3-5MPa pressure and 2-3 minutes to make the three layers tightly bonded. The prepared TPU / APP film is covered on the surface of the pre-composite board, and then hot-pressed again at 130-160℃ and 4-6MPa for 3-5 minutes to firmly wrap the film on the outside of the floor and form a decorative and anti-slip pattern, finally obtaining the flame-retardant stone plastic flooring product. The stone-plastic flooring prepared using the above method is as follows: The floor includes a base layer, an intermediate layer, a surface layer, and a covering layer, wherein the intermediate layer is placed between the base layer and the surface layer, and the covering layer is wrapped around the base layer, the intermediate layer, and the surface layer. The base layer comprises 60-70 parts of polyvinyl chloride resin, 200-250 parts of calcium carbonate powder, 3-5 parts of stabilizer, and 1-2 parts of lubricant; The intermediate layer comprises 70-80 parts of amorphous copolyester and 20-30 parts of aluminum hydroxide flame retardant; The surface layer comprises 70-80 parts of polyvinyl chloride resin, 10-15 parts of alumina wear-resistant agent, 5-8 parts of flame retardant, 1-2 parts of UV stabilizer, and 3-5 parts of stabilizer. The coating layer comprises 70-80 parts of thermoplastic polyurethane elastomer rubber and 20-30 parts of ammonium polyphosphate.

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