Lightweight diatom ooze PVC wallboard and preparation method thereof

Abstract

The invention discloses a light diatom ooze PVC wallboard and a preparation method thereof, and relates to the technical field of building materials. The lightweight diatom ooze PVC wallboard at least comprises the following raw materials in parts by weight: 40-75 parts of PVC resin powder, 15-40 parts of modified composite calcium powder, 5-15 parts of modified diatom ooze powder, 0.5-2 parts of a coupling agent, 0-1.5 parts of a foaming agent, 3-6 parts of an environment-friendly stabilizer, 1-3 parts of a lubricant, 3-10 parts of a flexibilizer and 0.5-1.5 parts of a processing aid. By adding the modified composite calcium powder and the modified diatom ooze, the impact resistance, the scratch resistance and the environmental protection property of the wallboard are remarkably improved, meanwhile, by means of the layered design that the raw materials are the same but the contents are different, the prepared light diatom ooze PVC wallboard achieves the optimal balance of mechanical properties and functional characteristics, has the decoration property, the safety and the environmental protection property, and is suitable for popularization and application. The composite board can be widely applied to the fields of prefabricated buildings, indoor partition walls, fireproof suspended ceilings and the like, and the market competitiveness is remarkable.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a lightweight diatom mud PVC wallboard and a preparation method thereof. Background Art

[0002] With increasing national requirements for energy conservation and environmental protection in building and decoration materials, and the increasing scarcity of timber resources, replacing wood with plastic has become the development trend of green building materials in my country. PVC co-extruded foam board is widely used in interior decoration, public building partitions, flooring, and other fields due to its low density, low thermal conductivity, dimensional stability, corrosion resistance, moisture resistance, good sound absorption, excellent flame retardancy and chemical resistance, and ease of processing with conventional machinery. PVC co-extruded foam board, also known as Chevron board and Andy board, is a type of PVC low-foam board. It is made from PVC resin as the main raw material, combined with a certain amount of foaming agent and other additives, and processed through extrusion. The PVC industry is currently developing rapidly worldwide and holds broad prospects. However, current PVC co-extruded foam board lacks toughness and is prone to breakage. The foaming process is difficult to control, making the resulting foam board difficult to meet user requirements.

[0003] Although PVC foam board has such a wide range of applications, its actual market share is relatively low, especially in the field of home decoration materials. The main limiting factor is the uneven quality of products. The products are not satisfactory in terms of strength, rigidity, thermal stability, etc., and there are safety hazards during use. In order to improve the comprehensive performance of PVC boards, the most commonly used method is to use polymer materials and inorganic fillers for blending and modification. Traditional PVC wall panels mostly use calcium powder as filler, but there are problems such as insufficient impact resistance and poor scratch resistance. Diatom mud has a good function of purifying indoor air. Although it can improve environmental performance, it has poor compatibility with the PVC matrix, which affects the mechanical properties. Therefore, the existing PVC co-extruded foam board has defects such as insufficient impact resistance, poor wear resistance, and insufficient environmental protection, which makes the use of this technology very limited. Summary of the Invention

[0004] The purpose of the present invention is to provide a lightweight diatom mud PVC wallboard and a preparation method thereof to solve the following technical problems:

[0005] Existing PVC co-extruded foam boards used as wallboard materials have problems such as insufficient impact resistance, poor scratch resistance and insufficient environmental friendliness.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A lightweight diatom mud PVC wallboard comprises at least the following raw materials in parts by weight:

[0008] 40-75 parts of PVC resin powder, 15-40 parts of modified composite calcium powder, 5-15 parts of modified diatom mud powder, 0.5-2 parts of coupling agent, 0-1.5 parts of foaming agent, 3-6 parts of environmentally friendly stabilizer, 1-3 parts of lubricant, 3-10 parts of toughening agent and 0.5-1.5 parts of processing aid.

[0009] Preferably, the lightweight diatom mud PVC wallboard includes at least a PVC layer and a PVC foam layer, and the PVC foam layer is arranged between the two PVC layers.

[0010] Preferably, the PVC layer comprises at least the following raw materials in parts by weight: 60-75 parts of PVC resin powder, 15-25 parts of modified composite calcium powder, 5-15 parts of modified diatom mud powder, 3-6 parts of environmentally friendly stabilizer, 1.5-3 parts of lubricant, 3-8 parts of toughening agent, 0.5-1.5 parts of coupling agent and 0.5-1.5 parts of processing aid;

[0011] The PVC foaming layer includes at least the following raw materials in parts by weight: 40-60 parts of PVC resin powder, 20-40 parts of modified composite calcium powder, 5-15 parts of modified diatom mud powder, 0.8-1.5 parts of foaming agent, 0.5-2 parts of coupling agent, 3-6 parts of environmentally friendly stabilizer, 1-3 parts of lubricant, 3-10 parts of toughening agent and 0.5-1.5 parts of processing aid.

[0012] Preferably, the preparation method of the modified diatom mud comprises the following steps:

[0013] Adding diatom mud into hydrochloric acid solution, washing and drying to obtain activated diatom mud;

[0014] The activated diatom mud is added to the hydrolyzed solution of the silane coupling agent, and the modified diatom mud is obtained after washing and drying.

[0015] Preferably, the mass ratio of the diatomaceous earth to the silane coupling agent is 100:1-2.

[0016] Preferably, the preparation method of the modified composite calcium powder comprises the following steps:

[0017] adding a sodium carbonate solution to a calcium chloride solution, then adding a barium chloride solution, and continuing to add the sodium carbonate solution, precipitating, filtering, washing, and drying to obtain barium carbonate-coated calcium sulfate;

[0018] Passing sulfur trioxide gas into the barium carbonate-coated calcium sulfate to obtain composite calcium powder;

[0019] The composite calcium powder is added into deionized water, stirred, and then the hydrolyzed surface modification agent is added, reacted, filtered, washed, and dried to obtain the modified composite calcium powder.

[0020] Preferably, the molar ratio of calcium ions to barium ions in the modified composite calcium powder is 8-15:1.

[0021] Preferably, the mass ratio of the surface modifier to the composite calcium powder is 0.5-3:100.

[0022] Preferably, the coupling agent is a mixture of any one or more of an aluminate coupling agent, a borate coupling agent, a silane coupling agent, a titanate coupling agent, and a maleic anhydride coupling agent; the environmentally friendly stabilizer is a calcium-zinc composite environmentally friendly stabilizer; the foaming agent is a mixture of any one or more of azodicarbonamide, sodium bicarbonate, or benzenesulfonyl hydrazide; the processing aid is a mixture of any one or more of polymethyl methacrylate, dioctyl phthalate, and ACR resin; the lubricant is a mixture of any one or more of stearic acid, calcium stearate, polyethylene wax, or oxidized polyethylene wax; and the toughening agent is a mixture of any one or more of chlorinated polyethylene, methyl methacrylate-butadiene-styrene copolymer, or ethylene-vinyl acetate copolymer.

[0023] A method for preparing a lightweight diatom mud PVC wallboard comprises at least the following preparation steps:

[0024] Add the raw materials of the PVC layer and the PVC foam layer into a high-speed mixer according to the weight ratio to obtain a PVC layer mixed material and a PVC foam layer mixed material;

[0025] The PVC layer mixed material and the PVC foam layer mixed material are added to the main extruder and the auxiliary extruder respectively, and then extruded from the discharge ports of the main and auxiliary extruders, enter the mold through the feed port of the mold through the distributor, and are cooled and shaped to form a structure with the middle layer being the PVC foam layer and the upper and lower layers being PVC layers, thereby obtaining a lightweight diatom mud PVC wall panel.

[0026] Beneficial effects of the present invention:

[0027] The lightweight diatom mud PVC wallboard prepared by the present invention is a three-layer PVC co-extruded foam board, the surface layer is a PVC board, and the core layer is a PVC foam board. In the present invention, the PVC board and the PVC foam board include PVC resin powder, modified composite calcium powder, modified diatom mud powder, a coupling agent, a foaming agent, an environmentally friendly stabilizer, a lubricant, a toughening agent and a processing aid. The PVC board of the present invention has a high resin content, which gives the surface layer high strength and wear resistance, and the PVC foam board is filled with high calcium powder, which gives the core layer impact resistance. The lightweight diatom mud PVC wallboard prepared by the present invention has the advantages of flame retardancy, waterproof and moisture-proof, moth-proof, zero formaldehyde, easy processing, time-saving and convenient. By adding modified composite calcium powder and modified diatom mud, the impact resistance, scratch resistance and environmental protection of the wallboard are significantly improved, while reducing the formulation cost. The present invention achieves an optimal balance between mechanical properties, functional characteristics and production costs through a layered design with the same raw materials but differentiated contents. The PVC board of the lightweight diatom mud PVC wall panel focuses on high strength and surface function, while the PVC foam board focuses on lightweight and multifunctionality. The two work together to form a better effect, which is both decorative, safe and environmentally friendly. It can be widely used in prefabricated buildings, interior partitions, fire-proof ceilings and other fields, and has significant market competitiveness.

[0028] The present invention utilizes a silane coupling agent to surface-modify diatom mud to obtain modified diatom mud. The amino group of the silane coupling agent forms a hydrogen bond with the chlorine atom of the PVC molecular chain, and at the same time, the siloxane group condenses with the hydroxyl group on the surface of the diatom mud, which significantly improves the interface bonding ability and functional properties of the diatom mud and PVC. The porous structure of the modified diatom mud absorbs stress and forms a "soft-hard" gradient with the rigid particles of the modified composite calcium powder, thereby improving the impact strength of the lightweight diatom mud PVC wallboard. In addition, the porous structure of the diatom mud can absorb formaldehyde in the air, and has the effect of purifying the air. It is an excellent environmentally friendly interior decoration material that meets people's requirements for environmental protection and health of living environment.

[0029] The modified composite calcium powder prepared by the present invention is a surface-modified barium sulfate-modified calcium carbonate. Barium sulfate has high hardness and high density. After coating light calcium carbonate, it can significantly improve the compressive strength, wear resistance and impact resistance of the composite material. Added as a filler in PVC wallboard, it can better disperse stress and reduce crack propagation. The barium sulfate coating layer can reduce the surface energy of light calcium carbonate and inhibit its agglomeration tendency, thereby improving the dispersion uniformity of the filler in the matrix. The barium sulfate surface can be further modified by a coupling agent to enhance the interfacial bonding force with the PVC matrix and reduce the interface defects between the filler and the matrix. The present invention can only give light calcium carbonate high performance through a coating process with only a small amount of barium sulfate. Compared with directly using a high proportion of barium sulfate, the cost is significantly reduced, and the low cost and easy processing characteristics of light calcium carbonate are retained. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] Example 1 The preparation method of modified composite calcium powder comprises the following steps:

[0032] A sodium carbonate solution with a concentration of 0.1 mol / L and a calcium chloride solution with a concentration of 0.1 mol / L containing 0.7 wt% of sodium hydroxide were prepared. The sodium carbonate solution was added dropwise to the calcium chloride solution at 30° C. until the residual percentage of calcium ions was 30 wt%. Barium chloride with a molar ratio of barium ions to calcium ions of 1:10 was dissolved in a small amount of water and added to the above reaction system. The sodium carbonate solution was continued to be added dropwise at 30° C. until the calcium ions and barium ions were completely precipitated. After filtering, washing, and drying, barium carbonate-coated calcium carbonate was obtained.

[0033] Passing sulfur trioxide gas into the barium carbonate-coated calcium carbonate to convert the barium carbonate into barium sulfate through gas-solid conversion to obtain composite calcium powder;

[0034] The above-mentioned composite calcium powder was added to 100 mL of deionized water, and after rapid stirring at room temperature for 1 hour, the hydrolyzed surface modifier KH570 was added, wherein the mass ratio of the composite calcium powder to the surface modifier was 100:1. The mixture was reacted in a 70°C water bath for 2 hours, filtered, and deionized water was repeatedly added to thoroughly wash the filtered solid. The solid was dried for 12 hours and ground to obtain the modified composite calcium powder.

[0035] Example 2 The preparation method of modified composite calcium powder comprises the following steps:

[0036] A sodium carbonate solution with a concentration of 0.1 mol / L and a calcium chloride solution with a concentration of 0.1 mol / L containing 0.7 wt% of sodium hydroxide were prepared, and the sodium carbonate solution was added dropwise to the calcium chloride solution at 30° C. until the residual percentage of calcium ions was 30 wt%. Barium chloride with a molar ratio of barium ions to calcium ions of 1:12 was dissolved in a small amount of water and added to the above reaction system. The sodium carbonate solution was continued to be added dropwise at 30° C. until the calcium ions and barium ions were completely precipitated. After filtering, washing, and drying, barium carbonate-coated calcium carbonate was obtained.

[0037] Passing sulfur trioxide gas into the barium carbonate-coated calcium carbonate to convert the barium carbonate into barium sulfate through gas-solid conversion to obtain composite calcium powder;

[0038] The above-mentioned composite calcium powder was added to 100 mL of deionized water, and after rapid stirring at room temperature for 1 hour, the hydrolyzed surface modifier KH570 was added, wherein the mass ratio of the composite calcium powder to the surface modifier was 100:1. The mixture was reacted in a 70°C water bath for 2 hours, filtered, and deionized water was repeatedly added to thoroughly wash the filtered solid. The solid was dried for 12 hours and ground to obtain the modified composite calcium powder.

[0039] Example 3 The preparation method of modified diatom mud comprises the following steps:

[0040] Add 100 g of dry diatomaceous earth to 1 mol / L hydrochloric acid solution, stir at room temperature for 4 h, let stand for 10 min, pour out the supernatant, wash and dry at 60 ° C for 24 h to obtain activated diatom mud;

[0041] 1.5 g of KH-550 was dissolved in a mixed solution of 450 mL of ethanol and 50 mL of water, magnetically stirred for 10 minutes, and hydrolyzed until transparent. The above diatom mud was added to the hydrolyzate of the silane coupling agent, heated in a water bath at 60 ° C, stirred continuously for 4 hours, washed, and vacuum dried at 80 ° C for 12 hours to obtain modified diatom mud.

[0042] Example 4 A lightweight diatom mud PVC wallboard is made by the following method:

[0043] The raw materials of the PVC layer (65 parts by weight of PVC resin powder SG-5, 20 parts by weight of modified composite calcium powder prepared in Example 1, 10 parts by weight of modified diatom mud powder prepared in Example 3, 5 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene, 1 part by weight of silane coupling agent and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer) and the PVC foam layer (50 parts by weight of PVC resin powder SG-5, 30 parts by weight of modified composite calcium powder prepared in Example 1, 10 parts by weight of modified diatom mud powder prepared in Example 3, 1 part by weight of azodicarbonamide, 1 part by weight of silane coupling agent, 3 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer) are added into a high-speed mixer respectively to obtain a PVC layer mixed material and a PVC foam layer mixed material;

[0044] The above-mentioned PVC layer mixture material and PVC foam layer mixture material are added into the main extruder and the auxiliary extruder respectively, and then extruded from the discharge port of the main and auxiliary extruders. The temperature of each zone of the main and auxiliary extruders is specifically as follows: zone 1 150-160°C, zone 2 155-165°C, zone 3 165-175°C, zone 4 170-180°C, mold 165-175°C, die lip 150-160°C, and enter the mold through the distributor through the feed port of the mold, cool and shape, and form a structure with a PVC foam layer in the middle layer and two PVC layers in the upper and lower layers to obtain lightweight diatom mud PVC wall panels.

[0045] Example 5 A lightweight diatom mud PVC wallboard is made by the following method:

[0046] In this embodiment, the raw materials for the PVC layer are 65 parts by weight of PVC resin powder SG-5, 20 parts by weight of modified composite calcium powder prepared in Example 2, 10 parts by weight of modified diatom mud powder prepared in Example 3, 5 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene, 1 part by weight of silane coupling agent and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer; the raw materials for the PVC foam layer are 50 parts by weight of PVC resin powder SG-5, 30 parts by weight of modified composite calcium powder prepared in Example 2, 10 parts by weight of modified diatom mud powder prepared in Example 3, 1 part by weight of azodicarbonamide, 1 part by weight of silane coupling agent, 3 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer. Apart from this, this embodiment is exactly the same as Example 4 and will not be repeated here.

[0047] Example 6 A lightweight diatom mud PVC wallboard is made by the following method:

[0048] In this embodiment, the raw materials of the PVC layer are 70 parts by weight of PVC resin powder SG-5, 15 parts by weight of modified composite calcium powder prepared in Example 1, 10 parts by weight of modified diatom mud powder prepared in Example 3, 5 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene, 1 part by weight of silane coupling agent and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer; the raw materials of the PVC foaming layer are 55 parts by weight of PVC resin powder SG-5, 35 parts by weight of modified composite calcium powder prepared in Example 1, 10 parts by weight of modified diatom mud powder prepared in Example 3, 1 part by weight of azodicarbonamide, 1 part by weight of silane coupling agent, 3 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer. Apart from this, this embodiment is exactly the same as Example 4 and will not be repeated here.

[0049] Example 7 A lightweight diatom mud PVC wallboard is made by the following method:

[0050] In this embodiment, the raw materials of the PVC layer are 70 parts by weight of PVC resin powder SG-5, 15 parts by weight of modified composite calcium powder prepared in Example 2, 10 parts by weight of modified diatom mud powder prepared in Example 3, 5 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene, 1 part by weight of silane coupling agent and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer; the raw materials of the PVC foaming layer are 55 parts by weight of PVC resin powder SG-5, 35 parts by weight of modified composite calcium powder prepared in Example 2, 10 parts by weight of modified diatom mud powder prepared in Example 3, 1 part by weight of azodicarbonamide, 1 part by weight of silane coupling agent, 3 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer. Apart from this, this embodiment is exactly the same as Example 4 and will not be repeated here.

[0051] Comparative Example 1 The preparation method of the mixture of modified barium sulfate and modified calcium carbonate comprises the following steps:

[0052] Barium sulfate and calcium carbonate with a molar ratio of barium ions to calcium ions of 1:10 were added to 100 mL of deionized water, and the mixture was rapidly stirred at room temperature for 1 hour. Then, the hydrolyzed surface modifier KH570 was added, wherein the mass ratio of the composite calcium powder to the surface modifier was 100:1. The mixture was reacted in a 70°C water bath for 2 hours, filtered, and deionized water was repeatedly added to fully wash the filtered solid. The solid was dried for 12 hours and ground to obtain a mixture of modified barium sulfate and modified calcium carbonate.

[0053] Comparative Example 2 Compared with Example 4, Comparative Example 2 only replaces the modified composite calcium powder prepared in Example 1 added in Example 4 with the modified diatom mud prepared in Example 3, and the other components and preparation methods are exactly the same as those in Example 4.

[0054] Comparative Example 3 Compared with Example 4, Comparative Example 3 only replaces the modified diatom mud prepared in Example 3 added in Example 4 with the modified composite calcium powder prepared in Example 1, and the other components and preparation methods are exactly the same as those in Example 4.

[0055] Comparative Example 4 Compared with Example 4, Comparative Example 4 only replaces the modified composite calcium powder prepared in Example 3 added in Example 4 with the modified barium sulfate and modified calcium carbonate mixture prepared in Comparative Example 1. The other components and preparation method are exactly the same as those in Example 4.

[0056] Comparative Example 5 Compared with Example 4, Comparative Example 5 only replaces the modified composite calcium powder prepared in Example 3 added in Example 4 with unmodified calcium carbonate. The other components and preparation method are completely consistent with those of Example 4.

[0057] Comparative Example 6 A lightweight diatom mud PVC wallboard is made by the following method:

[0058] In this embodiment, the raw materials of the PVC layer are 65 parts by weight of PVC resin powder SG-5, 20 parts by weight of modified composite calcium powder prepared in Example 1, 10 parts by weight of modified diatom mud powder prepared in Example 3, 5 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene, 1 part by weight of silane coupling agent and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer; the raw materials of the PVC foaming layer are 65 parts by weight of PVC resin powder SG-5, 20 parts by weight of modified composite calcium powder prepared in Example 1, 10 parts by weight of modified diatom mud powder prepared in Example 3, 5 parts by weight of calcium-zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene, 1 part by weight of silane coupling agent and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer, and 1 part by weight of azodicarbonamide. Apart from this, this embodiment is exactly the same as Example 4 and will not be repeated here.

[0059] Comparative Example 7 A lightweight diatom mud PVC wallboard is made by the following method:

[0060] In this embodiment, the raw materials of the PVC layer are 50 parts by weight of PVC resin powder SG-5, 30 parts by weight of modified composite calcium powder prepared in Example 1, 10 parts by weight of modified diatom mud powder prepared in Example 3, 1 part by weight of silane coupling agent, 3 parts by weight of calcium zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer; the raw materials of the PVC foaming layer are 50 parts by weight of PVC resin powder SG-5, 30 parts by weight of modified composite calcium powder prepared in Example 1, 10 parts by weight of modified diatom mud powder prepared in Example 3, 1 part by weight of azodicarbonamide, 1 part by weight of silane coupling agent, 3 parts by weight of calcium zinc composite environmentally friendly stabilizer, 2 parts by weight of calcium stearate, 5 parts by weight of chlorinated polyethylene and 1 part by weight of methyl methacrylate-butadiene-styrene copolymer. Except for this, this embodiment is exactly the same as Example 4 and will not be repeated here.

[0061] The properties of the lightweight diatom mud PVC wallboards obtained in Examples 4-7 and Comparative Examples 2-7 were tested below. The test results are shown in Table 1.

[0062] Table 1: Statistical table of wallboard performance test data in Examples 4-7 and Comparative Examples 2-7

[0063] <![CDATA[Impact strength kJ˙m 2 > Bending strength MPa Tensile strength MPa Thermal conductivity W / m˙K Formaldehyde adsorption rate% Pencil hardness Example 4 9.5 35 25 0.068 82 H Example 5 9.2 34 24 0.070 80 H Example 6 8.8 38 26 0.072 78 2H Example 7 8.7 37 25 0.073 77 2H Comparative Example 2 7.0 28 20 0.075 92 B Comparative Example 3 6.8 42 28 0.085 55 F Comparative Example 4 7.5 30 22 0.078 75 HB Comparative Example 5 5.5 25 18 0.090 70 3B Comparative Example 6 6.0 28 18 0.095 75 4B Comparative Example 7 7.2 30 20 0.080 78 B

[0064] As can be seen from Table 1, the lightweight diatom mud PVC wallboard prepared by the present invention has lightweight, impact resistance and scratch resistance, and through the differentiated design of the PVC layer and the PVC foam layer, the surface layer realizes the decorative and load-bearing functions, the core layer focuses on lightweight and heat preservation, and the two work together to achieve the goal of "lightweight, high-strength and multifunctional". In Comparative Example 2, no modified composite calcium powder is added, and the bending strength and scratch resistance of the obtained lightweight diatom mud PVC wallboard decrease. In Comparative Example 3, no modified diatom mud is added, and the formaldehyde adsorption rate of the obtained lightweight diatom mud PVC wallboard decreases. In Comparative Example 4, barium sulfate and calcium carbonate are not compounded, and the impact resistance of the obtained lightweight diatom mud PVC wallboard is greatly reduced. In Comparative Example 5, the calcium powder is not modified, and the impact resistance of the obtained lightweight diatom mud PVC wallboard decreases. In Comparative Example 6 and Comparative Example 7, the PVC layer and the PVC foam layer have the same content of other components except the foaming agent, and the obtained lightweight diatom mud PVC wallboard cannot achieve performance balance.

[0065] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A lightweight diatom mud PVC wallboard, characterized in that: At least include the following raw materials in parts by weight: 40-75 parts of PVC resin powder, 15-40 parts of modified composite calcium powder, 5-15 parts of modified diatom mud powder, 0.5-2 parts of coupling agent, 0-1.5 parts of foaming agent, 3-6 parts of environmentally friendly stabilizer, 1-3 parts of lubricant, 3-10 parts of toughening agent and 0.5-1.5 parts of processing aid.

2. A lightweight diatom mud PVC wallboard according to claim 1, characterized in that: The lightweight diatom mud PVC wallboard includes at least a PVC layer and a PVC foam layer, and the PVC foam layer is arranged between the two PVC layers.

3. A lightweight diatom mud PVC wallboard according to claim 2, characterized in that: The PVC layer comprises at least the following raw materials in parts by weight: 60-75 parts of PVC resin powder, 15-25 parts of modified composite calcium powder, 5-15 parts of modified diatom mud powder, 3-6 parts of environmentally friendly stabilizer, 1.5-3 parts of lubricant, 3-8 parts of toughening agent, 0.5-1.5 parts of coupling agent and 0.5-1.5 parts of processing aid; The PVC foaming layer includes at least the following raw materials in parts by weight: 40-60 parts of PVC resin powder, 20-40 parts of modified composite calcium powder, 5-15 parts of modified diatom mud powder, 0.8-1.5 parts of foaming agent, 0.5-2 parts of coupling agent, 3-6 parts of environmentally friendly stabilizer, 1-3 parts of lubricant, 3-10 parts of toughening agent and 0.5-1.5 parts of processing aid.

4. A lightweight diatom mud PVC wallboard according to claim 1, characterized in that: The preparation method of the modified diatom mud comprises the following steps: Adding diatom mud into hydrochloric acid solution, washing and drying to obtain activated diatom mud; The activated diatom mud is added to the hydrolyzed solution of the silane coupling agent, and the modified diatom mud is obtained after washing and drying.

5. A lightweight diatom mud PVC wallboard according to claim 4, characterized in that: The mass ratio of the diatomaceous earth to the silane coupling agent is 100:1-2.

6. A lightweight diatom mud PVC wallboard according to claim 1, characterized in that: The preparation method of modified composite calcium powder comprises the following steps: adding a sodium carbonate solution to a calcium chloride solution, then adding a barium chloride solution, and continuing to add the sodium carbonate solution, precipitating, filtering, washing, and drying to obtain barium carbonate-coated calcium sulfate; Passing sulfur trioxide gas into the barium carbonate-coated calcium sulfate to obtain composite calcium powder; The composite calcium powder is added into deionized water, stirred, and then the hydrolyzed surface modification agent is added, reacted, filtered, washed, and dried to obtain the modified composite calcium powder.

7. A lightweight diatom mud PVC wallboard according to claim 6, characterized in that: The molar ratio of calcium ions to barium ions in the modified composite calcium powder is 8-15:

1.

8. A lightweight diatom mud PVC wallboard according to claim 6, characterized in that: The mass ratio of the surface modifier to the composite calcium powder is 0.5-3:

100.

9. The lightweight diatom mud PVC wallboard according to claim 1, characterized in that: The coupling agent is any one or more mixtures of aluminate coupling agents, borate coupling agents, silane coupling agents, titanate coupling agents, and maleic anhydride coupling agents; the environmentally friendly stabilizer is a calcium-zinc composite environmentally friendly stabilizer; the foaming agent is any one or more mixtures of azodicarbonamide, sodium bicarbonate, or benzenesulfonyl hydrazide; the processing aid is any one or more mixtures of polymethyl methacrylate, dioctyl phthalate, and ACR resin; the lubricant is any one or more mixtures of stearic acid, calcium stearate, polyethylene wax, or oxidized polyethylene wax; and the toughening agent is any one or more mixtures of chlorinated polyethylene, methyl methacrylate-butadiene-styrene copolymer, or ethylene-vinyl acetate copolymer.

10. A method for preparing a lightweight diatom mud PVC wallboard, characterized in that: The method comprises at least the following preparation steps: Add the raw materials of the PVC layer and the PVC foam layer into a high-speed mixer according to the weight ratio to obtain a PVC layer mixed material and a PVC foam layer mixed material; The PVC layer mixed material and the PVC foam layer mixed material are added to the main extruder and the auxiliary extruder respectively, and then extruded from the discharge ports of the main and auxiliary extruders, enter the mold through the feed port of the mold through the distributor, and are cooled and shaped to form a structure with the middle layer being the PVC foam layer and the upper and lower layers being PVC layers, thereby obtaining a lightweight diatom mud PVC wall panel.