Flame-retardant PVC (polyvinyl chloride) wood-plastic wallboard as well as preparation method and application thereof

Abstract

The invention relates to a flame-retardant PVC wood-plastic wallboard, and relates to the technical field of wood-plastic products. The flame-retardant PVC wood-plastic wallboard comprises a surface layer and a core layer, the surface layer is combined to the surface of the core layer, and the surface layer is mainly prepared from polyvinyl chloride, a stabilizer, chlorinated polyethylene, sarin resin, a phosphorus-nitrogen flame retardant, a smoke suppressant, low-melting-point glass powder, kaolin and polyethylene wax. The core layer is mainly prepared from polyvinyl chloride, wood flour, calcium carbonate, antimony white, a foaming agent, a foaming regulator, a stabilizer, stearic acid and polyethylene wax. The flame-retardant PVC wood-plastic wallboard is formed by the self-developed surface layers and the core layer, so that the test requirements of the Korean flame-retardant standard KS F ISO 5660-2015 can be met, the mechanical property of the flame-retardant PVC wood-plastic wallboard can be ensured, the weight per meter is reduced, and the production cost of a product is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of wood-plastic products, in particular to a flame-retardant PVC wood-plastic wallboard and a preparation method and application thereof. Background Art

[0002] Technicians have done a lot of research on the flame retardancy of PVC wood plastic foam, but these technical studies focus more on the flame retardant effect of the product, and less on the surface cracking of the product after combustion. As the combustion of PVC wood plastic products progresses, the surface will crack, and this crack will run through the entire product, making PVC wood plastic products unable to meet the test requirements of the Korean flame retardant standard KS FISO 5660-2015.

[0003] In order to avoid such cracking after the product is burned, some researchers have proposed to use ceramicization to solve such problems. By adding ceramic fillers, ceramic flux, flame retardants and other materials into polymer materials, a flame retardant material that can be ceramicized is prepared. However, the PVC wood-plastic wallboard prepared by this method has a high content of inorganic fillers. When the filler content reaches 67% or more, a complete and hard surface will appear on the surface of the product after burning. Too much filler will reduce the mechanical properties of flame-retardant PVC, increase the weight of the product, and thus increase the cost of the product. Some researchers have also proposed adding low-melting point glass powder, with an addition amount of about 20-40 parts. However, the price of this low-melting point glass powder is relatively expensive, and a large amount will cause the cost of the entire product to increase significantly. Summary of the invention

[0004] In view of the above problems, the present invention provides a flame-retardant PVC wood-plastic wallboard, which is formed by a self-developed surface layer and a core layer. The flame-retardant PVC wood-plastic wallboard can not only meet the test requirements of the Korean flame retardant standard KS F ISO 5660-2015, but also ensure the mechanical properties of the flame-retardant PVC wood-plastic wallboard, and at the same time reduce the weight per meter, thereby reducing the production cost of the product.

[0005] In order to achieve the above object, the present invention provides a flame retardant PVC wood plastic wallboard, comprising a surface layer and a core layer, wherein the surface layer is bonded to the surface of the core layer;

[0006] The surface layer is mainly prepared from the following raw materials in parts by weight:

[0007]

[0008] The core layer is mainly prepared from the following raw materials in parts by weight:

[0009]

[0010] During the research process, the inventors found that the reason why conventional PVC foam flame retardant products cannot meet the test requirements of the Korean flame retardant standard KS FISO 5660-2015 and cracks appear throughout the entire product after combustion is that during the combustion process, under the action of high heat and oxygen, the polymer molecular chains shrink and crack rapidly, causing cracks to appear on the surface of the product. If one wants to use ceramicization to solve the above cracks and simply introduce ceramic fillers into the system, a large proportion of ceramic fillers is required to achieve a better anti-cracking effect, and a large proportion of ceramic fillers will lead to a decrease in mechanical properties, an increase in weight per meter, and an increase in production costs. Therefore, the inventors propose to prepare flame-retardant PVC wood-plastic wall panels (such as) by combining a surface layer and a core layer with each other. Figure 1 As shown in the figure, the surface layer is prepared by a formula without foaming raw materials, and has a good flame retardant effect. The core layer is prepared by a formula containing foaming raw materials, which can reduce the overall weight per meter of the flame retardant PVC wood-plastic wallboard. Through the coordination of the raw materials in the surface layer and the core layer, the prepared flame retardant PVC wood-plastic wallboard can meet the test requirements of the Korean flame retardant standard KS F ISO 5660-2015, and will not have cracks running through the entire product after burning, and has good mechanical properties, thereby reducing the weight per meter of the product.

[0011] In one embodiment, the core layer is a foamed layer, and the bonding is achieved by co-extrusion.

[0012] In one embodiment, the thickness of the surface layer is ≥2.5 mm.

[0013] When the thickness of the surface layer reaches the above degree, the prepared flame-retardant PVC wood-plastic wallboard has good flame-retardant properties.

[0014] In one embodiment, the density of the core layer is 0.5 g / cm 3 -0.9g / cm 3 .

[0015] In one embodiment, the surface layer is a non-foamed layer.

[0016] In one embodiment, the phosphorus-nitrogen flame retardant comprises an acid source and a gas source, the acid source comprises ammonium polyphosphate, and the gas source comprises melamine; the mass ratio of the acid source to the gas source is (2-4):1.

[0017] The inventors further discovered during the research that the flame retardant wallboards in the prior art are usually prepared using a single formula and do not have a layered structure. Therefore, flame retardants are often directly added to the formula to give the flame retardant wallboards better flame retardant properties. However, the present invention is intended to prepare a flame retardant PVC wood-plastic wallboard with a layered structure of a surface layer and a core layer. If the above idea of ​​directly adding flame retardants is still used, when the flame retardant PVC wood-plastic wallboard is prepared using co-extrusion technology, the surface layer and the core layer will debond due to the high addition ratio of the flame retardant. Therefore, the inventor proposes to introduce phosphorus-nitrogen flame retardants, low-melting glass powder, and kaolin into the surface layer formula. The phosphorus-nitrogen flame retardants only contain acid sources and gas sources, but no carbon source, so that the flame-retardant PVC wood-plastic wallboard can generate gas with the help of the combustion temperature during the combustion process, so that the ceramic materials such as the low-melting glass powder in the formula expand and ceramicize at the same time, forming a foamed ceramic-like substance, so that the surface of the flame-retardant PVC wood-plastic wallboard after combustion can form a hard surface similar to ceramic without cracking, and can also block the introduction of oxygen and heat with the help of the foamed ceramic-like substance, so that the surface layer has excellent flame retardant properties. The formula design of the above-mentioned surface layer requires that the ceramic filler has good sintering performance, and the amount of low-temperature glass powder and ceramic filler reaches a certain proportion. Therefore, the inventor selects kaolin, which is matched with low-temperature glass powder and phosphorus-nitrogen flame retardants, and the amount of low-temperature glass powder and kaolin is adjusted at the same time, so that the foamed ceramic-like substance can be generated after combustion.

[0018] In one embodiment, the stabilizer in the surface layer and the core layer includes at least one of a lead salt stabilizer, a calcium zinc stabilizer, a rare earth stabilizer, and an organic tin stabilizer;

[0019] The foaming agent includes at least one of azodicarbonamide, sodium bicarbonate, and zinc oxide;

[0020] The smoke suppressant includes at least one of ammonium octanoate and molybdenum trioxide;

[0021] The foaming regulator includes an acrylic copolymer.

[0022] In one embodiment, the foaming agent includes azodicarbonamide, sodium bicarbonate, and zinc oxide, and the mass ratio of azodicarbonamide, sodium bicarbonate, and zinc oxide is 1:(2-4):(0.05-0.15).

[0023] In one embodiment, the polyvinyl chloride in the surface layer and the core layer includes at least one of SG-7 type polyvinyl chloride resin and SG-8 type polyvinyl chloride resin;

[0024] The sarling resin is an ionic polymer of ethylene-(meth)acrylic acid zinc salt, and has a melt flow index of 2 to 4 g / 10 min;

[0025] The melting point of the low-melting-point glass powder is 300-500°C;

[0026] The intrinsic viscosity (25°C) of the acrylic copolymer is 8.0-9.0 dL·g -1 .

[0027] In one embodiment, the intrinsic viscosity (25° C.) of the acrylic copolymer is 8.3 dL·g -1 .

[0028] In one embodiment, the melting point of the low-melting-point glass powder is 350°C.

[0029] The present invention also provides a method for preparing the flame-retardant PVC wood-plastic wallboard, comprising the following steps:

[0030] Prepare the surface layer mixture material: weigh the raw materials of the surface layer, mix them, and mix them under cooling conditions to obtain the surface layer mixture material;

[0031] Prepare the core layer mixture material: weigh the raw materials of the core layer, mix wood powder and calcium carbonate, add polyvinyl chloride, antimony white, stabilizer, and foaming regulator, mix, add foaming agent, polyethylene wax, and stearic acid, mix, and mix under cooling conditions to obtain the core layer mixture material;

[0032] Preparation of flame-retardant PVC wood-plastic wallboard: co-extruding the surface layer mixed material and the core layer mixed material, cooling, and obtaining the flame-retardant PVC wood-plastic wallboard.

[0033] In one embodiment, in the step of preparing the surface layer mixture, the surface layer raw materials are weighed and mixed to a temperature of 120-130° C., and then mixed to a temperature of 35-45° C. under cooling conditions;

[0034] In the step of preparing the core layer mixture, the raw materials of the core layer are weighed, wood powder and calcium carbonate are mixed to a temperature of 85-95°C, polyvinyl chloride, antimony white, stabilizer, and foaming regulator are added, and the temperature is mixed to 100-105°C, and a foaming agent, polyethylene wax, and stearic acid are added and the temperature is mixed to 120-130°C, and the temperature is mixed to 35-45°C under cooling conditions.

[0035] In one embodiment, in the step of preparing the flame-retardant PVC wood-plastic wallboard, the co-extrusion is achieved by a co-extruder, and the temperatures of the sections from the hopper to the confluence core are: 120-140°C, 130-155°C, 150-165°C, 160-180°C, 170-185°C; the temperatures of the sections from the hopper to the mold are: 120-140°C, 130-155°C, 150-165°C, 155-170°C, 160-180°C, 185-195°C;

[0036] The working conditions of the main machine include: the screw speed is 9-13r / min, the speed of the main feed hopper feed screw is 15-30r / min;

[0037] The working conditions of the co-extruder include: the screw speed is 6-9r / min, and the speed of the main feeding hopper feed screw is 13-20r / min.

[0038] The invention also provides application of the flame-retardant PVC wood-plastic wallboard in building materials.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The flame-retardant PVC wood-plastic wallboard and its preparation method and application are formed by self-developed surface layer and core layer. The core layer is prepared by PVC wood-plastic foaming technology, which reduces the density of the product, reduces the weight per meter, reduces the production cost of the product, and enables the wallboard to play a role of heat insulation; the surface layer adopts a flame-retardant PVC material formula to ensure that the wallboard has mechanical properties and flame-retardant properties that meet standard requirements; the prepared flame-retardant PVC wood-plastic wallboard has a density of 0.5g / cm 3 -0.9g / cm 3 , close to the density of solid wood, and has good heat insulation effect; at the same time, the product can meet the test requirements of Korean flame retardant standard KS F ISO 5660-2015; after the flame retardant test, no cracking occurred on the surface of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the structure of the flame-retardant PVC wood-plastic board of the present invention, wherein 1 is the surface layer and 2 is the core layer;

[0042] Figure 2 This is a schematic diagram of surface cracking after combustion in Comparative Example 2;

[0043] Figure 3 This is a schematic diagram of the surface condition after combustion of Example 2. DETAILED DESCRIPTION

[0044] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0046] source:

[0047] Unless otherwise specified, the reagents, materials, and equipment used in this example are all commercially available; the experimental methods are all conventional experimental methods in the art unless otherwise specified.

[0048] Example 1

[0049] A flame-retardant PVC wood-plastic wallboard and a preparation method thereof.

[0050] The preparation method is as follows:

[0051] 1. Weigh the materials according to the following formula:

[0052] 1. Surface material:

[0053]

[0054]

[0055] 2. Core layer material:

[0056]

[0057] In this embodiment, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer with an intrinsic viscosity (25°C) of 8.3 dL·g -1 .

[0058] 2. Preparation of flame-retardant PVC wood-plastic wall panels.

[0059] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0060] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0061] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0062] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7 mm, of which the co-extrusion layer thickness is 2.5 mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface layer thickness of 2.5 mm;

[0063] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0064] Example 2

[0065] A flame-retardant PVC wood-plastic wallboard and a preparation method thereof.

[0066] The preparation method is as follows:

[0067] 1. Weigh the materials according to the following formula:

[0068] 1. Surface material:

[0069]

[0070] 2. Core layer material:

[0071]

[0072] In this embodiment, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer with an intrinsic viscosity (25°C) of 8.3 dL·g -1 .

[0073] 2. Preparation of flame-retardant PVC wood-plastic wall panels.

[0074] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0075] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0076] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0077] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7 mm, of which the co-extrusion layer thickness is 2.5 mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface layer thickness of 2.5 mm;

[0078] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0079] Example 3

[0080] A flame-retardant PVC wood-plastic wallboard and a preparation method thereof.

[0081] The preparation method is as follows:

[0082] 1. Weigh the materials according to the following formula:

[0083] 1. Surface material:

[0084]

[0085] 2. Core layer material:

[0086]

[0087] In this embodiment, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer with an intrinsic viscosity (25°C) of 8.3 dL·g -1 .

[0088] 2. Preparation of flame-retardant PVC wood-plastic wall panels.

[0089] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0090] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0091] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0092] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7 mm, of which the co-extrusion layer thickness is 2.5 mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface layer thickness of 2.5 mm;

[0093] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0094] Example 4

[0095] A flame-retardant PVC wood-plastic wallboard and a preparation method thereof.

[0096] The preparation method is as follows:

[0097] 1. Weigh the materials according to the following formula

[0098] 1. Surface material:

[0099]

[0100] 2. Core layer material:

[0101]

[0102]

[0103] In this embodiment, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer with an intrinsic viscosity (25°C) of 8.3 dL·g -1 .

[0104] 2. Preparation of flame-retardant PVC wood-plastic wall panels.

[0105] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0106] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0107] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0108] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7 mm, of which the co-extrusion layer thickness is 2.5 mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface layer thickness of 2.5 mm;

[0109] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0110] Example 5

[0111] A flame-retardant PVC wood-plastic wallboard and a preparation method thereof.

[0112] The preparation method is as follows:

[0113] 1. Weigh the materials according to the following formula:

[0114] 1. Surface material:

[0115]

[0116]

[0117] 2. Core layer material:

[0118]

[0119] In this embodiment, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer with an intrinsic viscosity (25°C) of 8.3 dL·g -1 .

[0120] 2. Preparation of flame-retardant PVC wood-plastic wall panels.

[0121] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0122] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0123] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0124] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7 mm, of which the co-extrusion layer thickness is 2.5 mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface layer thickness of 2.5 mm;

[0125] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0126] Example 6

[0127] A flame-retardant PVC wood-plastic wallboard and a preparation method thereof.

[0128] The preparation method is as follows:

[0129] 1. Weigh the materials according to the following formula:

[0130] 1. Surface material:

[0131]

[0132] 2. Core layer material:

[0133]

[0134] In this embodiment, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer with an intrinsic viscosity (25°C) of 8.3 dL·g -1 .

[0135] 2. Preparation of flame-retardant PVC wood-plastic wall panels.

[0136] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0137] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0138] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0139] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7mm, of which the co-extrusion layer thickness is 1.5mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface layer thickness of 1.5mm;

[0140] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0141] Example 7

[0142] A flame-retardant PVC wood-plastic wallboard and a preparation method thereof.

[0143] The preparation method is as follows:

[0144] 1. Weigh the materials according to the following formula:

[0145] 1. Surface material:

[0146]

[0147] 2. Core layer material:

[0148]

[0149] In this embodiment, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer with an intrinsic viscosity (25°C) of 8.3 dL·g -1 .

[0150] 2. Preparation of flame-retardant PVC wood-plastic wall panels.

[0151] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0152] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0153] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0154] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7mm, of which the co-extrusion layer thickness is 1.5mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface layer thickness of 1.5mm;

[0155] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0156] Example 8

[0157] 1. Weigh the materials according to the following formula

[0158] Surface material:

[0159]

[0160] 2. Core layer material:

[0161]

[0162]

[0163] In this embodiment, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer with an intrinsic viscosity (25°C) of 8.3 dL·g -1 .

[0164] 2. Preparation of flame-retardant PVC wood-plastic wall panels.

[0165] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0166] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0167] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0168] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7mm, of which the co-extrusion layer thickness is 1.5mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface layer thickness of 1.5mm;

[0169] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0170] Comparative Example 1

[0171] A PVC wood-plastic wallboard and a preparation method thereof.

[0172] The preparation method is as follows:

[0173] 1. Weigh the materials according to the following formula:

[0174]

[0175] 2. Preparation of PVC wood-plastic wall panels.

[0176] 1. Put the above materials into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature materials into a cold mixer and continue mixing until the material temperature drops to 40°C to obtain a flame-retardant wallboard mixture;

[0177] 2. Add the mixed materials to the hopper of the conical double extruder. Set the temperature of each section of the main extruder from the hopper to the die as follows: Zone 1 130°C, Zone 2 of the main extruder 140°C, Zone 3 of the main extruder 165°C, Zone 4 of the main extruder 170°C, confluence core 170°C, and die 185°C. The screw speed of the main extruder is 11r / min, and the speed of the feed screw of the main feeding hopper is 30r / min;

[0178] 3. The material is extruded through a twin-screw extruder and flows through a die (without a co-extrusion layer, and the overall wall thickness of the product is 7mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC wallboard;

[0179] 4. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0180] Comparative Example 2

[0181] A PVC wood-plastic wallboard and a preparation method thereof.

[0182] The preparation method is as follows:

[0183] 1. Weigh the materials according to the following formula

[0184]

[0185] In this comparative example, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer, and the intrinsic viscosity (25°C) is 8.3 dL·g -1 .

[0186] 2. Preparation of PVC wood-plastic wall panels.

[0187] 1. Put the oak powder, low melting point glass powder and kaolin in the formula into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax and stearic acid, and continue stirring until the temperature reaches 120°C; put the materials into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain a PVC wood-plastic wallboard mixture;

[0188] 2. Add the mixed materials to the hopper of the conical double extruder. Set the temperature of each section of the main extruder from the hopper to the die as follows: Zone 1 130°C, Zone 2 140°C, Zone 3 165°C, Zone 4 170°C, confluence core 170°C, and die 185°C. The screw speed of the main extruder is 9r / min, and the speed of the feed screw of the main feeding hopper is 20r / min;

[0189] 3. The material is extruded through a twin-screw extruder and flows through a die (without a co-extrusion layer, and the overall wall thickness of the product is 7mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC wallboard;

[0190] 4. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0191] Comparative Example 3

[0192] A PVC wood-plastic wallboard and a preparation method thereof.

[0193] The preparation method is as follows:

[0194] 1. Weigh the materials according to the following formula

[0195] 1. Surface material:

[0196]

[0197] 2. Core layer material:

[0198]

[0199] In this comparative example, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer, and the intrinsic viscosity (25°C) is 8.3 dL·g -1 .

[0200] 2. Preparation of PVC wood-plastic wall panels.

[0201] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0202] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0203] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0204] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7mm, of which the co-extrusion layer thickness is 2.5mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface thickness of 2.5mm;

[0205] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0206] Comparative Example 4

[0207] A PVC wood-plastic wallboard and a preparation method thereof.

[0208] The preparation method is as follows:

[0209] 1. Weigh the materials according to the following formula

[0210] 1. Surface material:

[0211]

[0212] 2. Core layer material:

[0213]

[0214]

[0215] In this comparative example, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer, and the intrinsic viscosity (25°C) is 8.3 dL·g -1 .

[0216] 2. Preparation of PVC wood-plastic wall panels.

[0217] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0218] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the core layer mixture;

[0219] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0220] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7mm, of which the co-extrusion layer thickness is 2.5mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface thickness of 2.5mm;

[0221] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0222] Comparative Example 5

[0223] A PVC wood-plastic wallboard and a preparation method thereof.

[0224] The preparation method is as follows:

[0225] 1. Weigh the materials according to the following formula

[0226] 1. Surface material:

[0227]

[0228]

[0229] 2. Core layer material:

[0230]

[0231] In this comparative example, the foaming agent is a composite foaming agent, which is composed of azodicarbonamide, sodium bicarbonate, and zinc oxide in a mass ratio of 1:3:0.1; the foaming regulator is an acrylic copolymer, and the intrinsic viscosity (25°C) is 8.3 dL·g -1 .

[0232] 2. Preparation of PVC wood-plastic wall panels.

[0233] 1. Prepare the surface layer mixture: put the surface layer material into a high-speed mixer and mix until the material temperature reaches 120°C; put the high-temperature material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the surface layer mixture;

[0234] 2. Prepare the core layer mixture: put the oak powder and light calcium carbonate in the core layer material into a high mixing pot and mix them to a temperature of 90°C; add polyvinyl chloride, antimony white, calcium zinc stabilizer, and foaming regulator, and mix at high speed until the material temperature reaches 105°C; add foaming agent, polyethylene wax, and stearic acid, and continue stirring until the temperature reaches 120°C; put the material into a cold mixing pot and continue mixing until the material temperature drops to 40°C to obtain the flame retardant wallboard core layer mixture;

[0235] 3. Preparation of flame-retardant PVC wood-plastic wall panels: add the mixed surface layer materials to the hopper of the conical double co-extruder, and add the core layer materials to the hopper of the conical double extruder main machine. Set the temperatures of each section of the co-extruder from the hopper to the confluence core as follows: 130°C for zone 1, 150°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 180°C for zone 4 for the main machine, and 185°C for the confluence core; set the temperatures of each section of the main extruder from the hopper to the mold as follows: 130°C for zone 1, 140°C for zone 2 for the main machine, 165°C for zone 3 for the main machine, 170°C for zone 4 for the main machine, 170°C for the confluence core, and 185°C for the mold. The screw speed of the main machine is 9r / min, the speed of the feed screw of the main feeding hopper is 20r / min, the screw speed of the co-extruder is 6r / min, and the speed of the feed screw of the main feeding hopper is 13r / min;

[0236] 4. The material is extruded through a twin-screw extruder and flows through a die (the overall wall thickness of the product is 7mm, of which the co-extrusion layer thickness is 1.5mm) to form a board embryo. After the board embryo exits the die, it enters a shaping table for cooling to obtain a flame-retardant PVC foam wallboard with a surface layer thickness of 1.5mm;

[0237] 5. The formed flame-retardant PVC foam wall panels are continuously transported forward by the traction unit and enter the cutting table to be cut into standard sizes.

[0238] Experimental example

[0239] The performance of the PVC wood-plastic wallboards prepared in the above embodiments and comparative examples was tested, and the results are shown in the following table.

[0240] Table 1 Performance test results of PVC wood-plastic wallboards prepared in various embodiments and comparative examples

[0241]

[0242]

[0243] Comparative Example 2 cracked on the surface after burning. Figure 2 As shown, the surface condition after combustion of Example 2 is as follows Figure 3 shown.

[0244] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0245] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A flame retardant PVC wood-plastic wallboard, characterized in that: It comprises a surface layer and a core layer, wherein the surface layer is bonded to the surface of the core layer; The surface layer is mainly prepared from the following raw materials in parts by weight: The core layer is mainly prepared from the following raw materials in parts by weight:

2. The flame retardant PVC wood-plastic wallboard according to claim 1, characterized in that: The core layer is a foamed layer, and the bonding is achieved by co-extrusion.

3. The flame retardant PVC wood-plastic wallboard according to claim 1, characterized in that: The thickness of the surface layer is ≥2.5 mm.

4. The flame retardant PVC wood-plastic wallboard according to claim 1, characterized in that: The phosphorus-nitrogen flame retardant comprises an acid source and a gas source, wherein the acid source comprises ammonium polyphosphate, and the gas source comprises melamine; and the mass ratio of the acid source to the gas source is (2-4):

1.

5. The flame retardant PVC wood-plastic wallboard according to claim 1, characterized in that: The stabilizer in the surface layer and the core layer includes at least one of a lead salt stabilizer, a calcium zinc stabilizer, a rare earth stabilizer, and an organic tin stabilizer; The foaming agent includes at least one of azodicarbonamide, sodium bicarbonate, and zinc oxide; The smoke suppressant includes at least one of ammonium octanoate and molybdenum trioxide; The foaming regulator includes an acrylic copolymer.

6. The flame retardant PVC wood-plastic wallboard according to claim 5, characterized in that: The foaming agent comprises azodicarbonamide, sodium bicarbonate and zinc oxide, and the mass ratio of azodicarbonamide, sodium bicarbonate and zinc oxide is 1:(2-4):(0.05-0.15).

7. The method for preparing the flame retardant PVC wood plastic wallboard according to any one of claims 1 to 6, characterized in that: The following steps are involved: Prepare the surface layer mixture material: weigh the raw materials of the surface layer, mix them, and mix them under cooling conditions to obtain the surface layer mixture material; Prepare the core layer mixture material: weigh the raw materials of the core layer, mix wood powder and calcium carbonate, add polyvinyl chloride, antimony white, stabilizer, and foaming regulator, mix, add foaming agent, polyethylene wax, and stearic acid, mix, and mix under cooling conditions to obtain the core layer mixture material; Preparation of flame-retardant PVC wood-plastic wallboard: co-extruding the surface layer mixed material and the core layer mixed material, cooling, and obtaining the flame-retardant PVC wood-plastic wallboard.

8. The preparation method according to claim 7, characterized in that: In the step of preparing the surface layer mixture, the surface layer raw materials are weighed and mixed to a temperature of 120-130° C., and then mixed to a temperature of 35-45° C. under cooling conditions; In the step of preparing the core layer mixture, the raw materials of the core layer are weighed, wood powder and calcium carbonate are mixed to a temperature of 85-95°C, polyvinyl chloride, antimony white, stabilizer, and foaming regulator are added, and the temperature is mixed to 100-105°C, and a foaming agent, polyethylene wax, and stearic acid are added and the temperature is mixed to 120-130°C, and the temperature is mixed to 35-45°C under cooling conditions.

9. The preparation method according to claim 7, characterized in that: In the step of preparing the flame-retardant PVC wood-plastic wallboard, the co-extrusion is achieved by a co-extruder, and the temperatures of the sections from the hopper to the confluence core are respectively: 120-140°C, 130-155°C, 150-165°C, 160-180°C, 170-185°C; the temperatures of the sections from the hopper to the mold are respectively: 120-140°C, 130-155°C, 150-165°C, 155-170°C, 160-180°C, 185-195°C; The working conditions of the main machine include: the screw speed is 9-13r / min, the speed of the main feed hopper feed screw is 15-30r / min; The working conditions of the co-extruder include: the screw speed is 6-9r / min, and the speed of the main feeding hopper feed screw is 13-20r / min.

10. Use of the flame-retardant PVC wood-plastic wallboard according to any one of claims 1 to 6 in building materials.

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