Moulded wood-plastic composite floor and production process thereof

Abstract

The application discloses a kind of moulded wood-plastic composite floor and its production process.The wood-plastic composite floor provided by the application includes base layer and reinforcing layer, the base layer and the reinforcing layer are bonded by adhesive, the floor is provided with circular arc edge and lock catch structure around, and the floor can be spliced by lock catch structure.The base layer is PVC board, and the raw materials include: PVC resin powder 5 type, heat stabilizer, plasticizer and reinforcing filler.The reinforcing layer is wood-plastic composite board, and the raw materials include: PVC resin powder 5 type, PVC resin powder 7 type, plant fiber, heat stabilizer, end epoxy flame retardant, reinforcing filler, lubricant, white foaming agent, yellow foaming agent, foaming regulator and catalyst.The wood-plastic composite floor provided by the application has excellent flame retardant performance, higher bending strength and lower water absorption.

Description

Technical Field

[0001] This invention relates to the field of flooring technology, specifically to a molded wood-plastic composite floor and its manufacturing process. Background Technology

[0002] Biomass molded flooring refers to flooring made of wood-plastic composites (WPC). WPC flooring has gained widespread attention and application due to its advantages such as strong plasticity, recyclability, and low price. However, most existing WPC flooring technologies use PVC sheets as the base layer, which are brittle and have poor impact resistance, affecting not only subsequent processing but also the product's appearance. To avoid these issues, small sheets (190mm × 1200-1800mm) are typically used during molding, resulting in a complex process and low processing efficiency.

[0003] PVC resin, as one of the base materials for manufacturing molded flooring, possesses excellent wear resistance, good weather resistance, and chemical stability. However, PVC materials generally suffer from drawbacks such as poor toughness and flammability. Therefore, it is necessary to add additives to improve the material's performance. However, achieving good results requires higher additive amounts, which not only increases production costs but also reduces other material properties, making it difficult to obtain flooring that combines good mechanical properties, excellent flame retardancy, and low water absorption. Therefore, researchers need to develop flooring with high flame retardancy, low water absorption, and excellent mechanical properties to meet people's needs. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a molded wood-plastic composite flooring and its manufacturing process.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A molded wood-plastic composite floor includes a base layer and a reinforcing layer, which are bonded together by an adhesive. The floor has rounded edges and a locking structure around its perimeter, allowing the floorboards to be interlocked and spliced ​​together via the locking structure.

[0007] Furthermore, after the floorboards are interlocked and spliced ​​together by the aforementioned locking structure, a γ-shaped double arc structure is formed at the splice point;

[0008] Furthermore, the arc edge is the same color as the surface of the floor body and forms a continuous whole;

[0009] The substrate layer is a PVC sheet, which includes, by weight: 100 parts of PVC resin powder type 5, 3-4 parts of heat stabilizer, 0.8-2 parts of plasticizer, and 15-25 parts of reinforcing filler;

[0010] The reinforcing layer is a wood-plastic composite board, comprising, by weight: 70-90 parts of PVC resin powder type 5, 80-90 parts of PVC resin powder type 7, 50-60 parts of plant fiber, 5-11 parts of heat stabilizer, 3-7 parts of end-epoxy flame retardant, 20-40 parts of reinforcing filler, 1-2 parts of lubricant, 0.8-1 part of white foaming agent, 0.8-1 part of yellow foaming agent, 2-3 parts of foaming regulator, and 0.5-1.5 parts of catalyst;

[0011] The reinforcing filler is prepared by the following steps:

[0012] Step A1: Add 3-chloropropyltrimethoxysilane to a flask containing anhydrous ethanol and stir until homogeneous. Transfer the mixture to an oil bath and raise the system temperature to 65°C. Slowly add dodecyl dimethyl tertiary amine at 200 rpm and continue stirring for 6-8 hours. After the reaction is complete, cool to room temperature, distill under reduced pressure, and wash to obtain quaternary ammonium silane.

[0013] Furthermore, the ratio of 3-chloropropyltrimethoxysilane, anhydrous ethanol, and dodecyl dimethyl tertiary amine is 10-20 mL: 100 mL: 8-15 mL;

[0014] Step A2: Disperse nano-calcium carbonate in anhydrous ethanol by ultrasonication, add toluene dropwise and mix well, then add tridecafluorooctyltrimethoxysilane and quaternary ammonium salt silane. Stir the mixture at 30°C for 5-7 hours. After the reaction is complete, centrifuge, wash and dry at 40°C to obtain the reinforcing filler.

[0015] Furthermore, the ratio of nano-calcium carbonate, anhydrous ethanol, toluene, tridecafluorooctyltrimethoxysilane, and quaternary ammonium silane is 5g:30mL:2-4mL:3-5mL:2-3g;

[0016] The terminal epoxy flame retardant is prepared by the following steps:

[0017] Step B1: Add MgCl2·6H2O, AlCl3·6H2O and BCl3 to a beaker containing deionized water and mix thoroughly by ultrasonication. This solution is denoted as solution A. Add NaOH and Na2CO3 to a beaker containing deionized water and mix thoroughly by ultrasonication. This solution is denoted as solution B. Under stirring conditions, add solutions A and B dropwise to the beaker containing deionized water and maintain the pH of the mixture at 9-10. After the addition is complete, transfer the mixture to a water bath, heat it to 60℃, and maintain the temperature for aging for 12 hours. After aging, filter and wash the mixture. Place the precipitate in a vacuum dryer at 60℃ for 12 hours and grind it to obtain BMgAl-LDH.

[0018] Furthermore, the volume ratio of solution A, solution B, and deionized water is 1:1:2. The ratio of the amount of MgCl2·6H2O, AlCl3·6H2O, BCl3, and deionized water in solution A is 2 mol: 1 mol: 0.2-1 mol: 100 mL. The ratio of the amount of NaOH, Na2CO3, and deionized water in solution B is 3 mol: 1 mol: 100 mL.

[0019] Step B2: Add BMgAl-LDH, KH550 and 1,4-dioxane to a flask, stir and react at 90°C for 6 hours, then lower the temperature to 15°C, add cyanuric chloride and stir for 10 minutes, then slowly add triethylamine and continue stirring for 4 hours. After the reaction is complete, intermediate product 1 is obtained.

[0020] Furthermore, the ratio of BMgAl-LDH, KH550, 1,4-dioxane, cyanuric chloride and triethylamine is 2-3g: 2.21-4.42g: 200mL: 1.84-3.68g: 1.01-2.02g.

[0021] Step B3: Add a mixture of ethylenediamine, NaOH and deionized water dropwise to intermediate product 1, and heat to 50°C and react for 2 hours. Then raise the system temperature to 90°C, add the same mixture dropwise again, and continue to reflux for 8 hours. After the reaction is completed, lower to room temperature, filter, wash, and dry at 60°C for 12 hours to obtain intermediate product 2.

[0022] Furthermore, the ratio of ethylenediamine, NaOH, and deionized water in the mixture is 0.01 mol: 0.8 g: 200 mL.

[0023] Step B4: Add intermediate product 2 and NaOH to a reactor containing anhydrous ethanol and stir until homogeneous. Then add epichlorohydrin and stir for 2-3 hours. After the reaction is complete, distill under reduced pressure. Then slowly add 25wt% NaOH solution to the mixture and heat to 80℃ for 3 hours. After the reaction is complete, filter, wash, and vacuum dry at 80℃ for 12 hours to obtain the terminal epoxy flame retardant.

[0024] Furthermore, the ratio of intermediate product 2, NaOH, anhydrous ethanol, epichlorohydrin and NaOH solution is 1-2g: 0.01-0.02mol: 30-50mL: 0.02-0.04mol: 10-20mL.

[0025] A manufacturing process for molded wood-plastic composite flooring includes the following steps:

[0026] Step S1: Weigh the raw materials according to the weight proportions, stir the PVC resin powder type 5, heat stabilizer, plasticizer and reinforcing filler at 130-150℃ and 700-900rpm for 30min, then extrude the mixture at an extrusion temperature of 150-170℃, an extrusion speed of 140-160rpm / min and an extrusion pressure of 5-7MPa, and then cool and set it to obtain PVC sheet.

[0027] Step S2: Weigh the raw materials according to the weight proportions, mix PVC resin powder type 5, PVC resin powder type 7 and plant fiber evenly, add heat stabilizer, end epoxy flame retardant, reinforcing filler, lubricant, white foaming agent, yellow foaming agent, foaming regulator and catalyst, stir for 40 minutes at 140-150℃ and 800-900rpm, then extrude the mixture at an extrusion temperature of 180-200℃, an extrusion speed of 150-170rpm / min and an extrusion pressure of 5-7MPa, and cool and set to obtain wood-plastic composite board;

[0028] Step S3: Apply adhesive evenly to the upper surface of the PVC board and bond it to the wood-plastic composite board. After bonding, mold and cut to obtain the molded wood-plastic composite flooring.

[0029] Furthermore, the adhesive is diphenylmethane diisocyanate, and the molding process is carried out at a temperature of 30-40℃, a pressure of 10-12MPa, and a time of 60s.

[0030] The beneficial effects of this invention are:

[0031] The molded wood-plastic composite flooring provided by this invention uses PVC board as the base layer and wood-plastic composite board as the reinforcing layer. The boards are bonded together with an adhesive and then molded. The resulting flooring has rounded edges and a locking structure, allowing the floorboards to be interlocked together. First, reinforcing fillers are added to both the base layer and the reinforcing layer, effectively improving the mechanical properties of the matrix. Second, epoxy flame retardants and plant fibers are added to the reinforcing layer, improving the flame retardancy and toughness of the matrix.

[0032] In the reinforcing filler, nano-calcium carbonate is used as a rigid particle, and its surface is coated with organosilicon containing fluorine and long-chain hydrophobic structures to obtain the reinforcing filler. First, the nano-calcium carbonate is uniformly dispersed in the matrix. When subjected to external impact, the stress concentration effect of montmorillonite causes countless tiny cavities and voids to be generated in the matrix, thereby consuming energy and transforming the matrix from brittle to tough, thus improving the mechanical properties of the matrix. Second, the fluorine-containing long chains and hydrophobic long chains on the surface of nano-calcium carbonate work synergistically to give the matrix excellent hydrophobicity, thereby improving the water resistance of the matrix. Finally, the quaternary ammonium salt structure in the organosilicon coating layer improves the antistatic effect of the matrix.

[0033] In the epoxy flame retardant, firstly, boron-doped hydrotalcite is prepared using a co-precipitation method, which improves the flame retardant properties of hydrotalcite. This is because the layered structure of hydrotalcite contains structural water and carbonate ions, which release water and carbon dioxide when the temperature rises, reducing the concentration of flammable gases in the surrounding environment. At the same time, the decomposition of hydrotalcite is endothermic, which can lower the surface temperature of the material. During combustion, boron generates borate, which promotes the formation of a dense char layer in the matrix and hinders the release of volatile combustibles, thus achieving flame retardancy. Secondly, the surface of BMgAl-LDH is modified with a silane coupling agent to contain amino groups. Then, the amino groups undergo a substitution reaction with the chlorine atoms on melamine chloride, thereby grafting BMgAl-LDH onto melamine chloride. This allows BMgAl-LDH to work synergistically with melamine chloride, further improving the flame retardant properties of the matrix. Secondly, the amino group on ethylenediamine undergoes a nucleophilic substitution reaction with the chlorine atom in intermediate 1, resulting in a terminal amino group on intermediate 2. This terminal amino group can undergo a ring-opening reaction with the epoxy group on epichlorohydrin. Then, under alkaline conditions, the chloromethyl group in the product reacts with a hydroxyl group to generate a new epoxy group, thus yielding a terminal epoxy flame retardant. When this terminal epoxy group is blended with plant fibers, it reacts with the hydroxyl groups in the plant fibers, grafting onto the surface of the plant fibers. This avoids the precipitation and loss of the flame retardant during production, reducing production costs. Finally, the terminal epoxy flame retardant, after grafting onto plant fibers, not only has a flame-retardant effect but also acts as a coupling agent, effectively reducing the dispersion between plant fibers and making the mixture more uniform. Furthermore, the flame retardant contains rigid layered hydrotalcite, increasing the toughness of the matrix and forming a synergistic effect with the plant fibers, enhancing the impact resistance of the matrix. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] 1) The reinforcing filler is prepared by the following steps:

[0037] Step A1: Add 10 mL of 3-chloropropyltrimethoxysilane to a flask containing 100 mL of anhydrous ethanol and stir until homogeneous. Transfer the mixture to an oil bath, raise the system temperature to 65 °C, and slowly add 8 mL of dodecyl dimethyl tertiary amine at 200 rpm. Continue stirring for 6 h. After the reaction is complete, cool to room temperature, distill under reduced pressure, and wash to obtain quaternary ammonium silane.

[0038] Step A2: Disperse 5g of nano-calcium carbonate ultrasonically into 30mL of anhydrous ethanol, add 2mL of toluene and mix well, then add 3mL of tridecafluorooctyltrimethoxysilane and 2g of quaternary ammonium salt silane. Stir the mixture at 30℃ for 5h. After the reaction is complete, centrifuge, wash and dry at 40℃ to obtain the reinforcing filler.

[0039] 2) The epoxy flame retardant is prepared by the following steps:

[0040] Step B1: Add 2 mol MgCl2·6H2O, 1 mol AlCl3·6H2O and 0.2 mol BCl3 to a beaker containing 100 mL deionized water and mix thoroughly by ultrasonication. This solution is denoted as solution A. Add 3 mol NaOH and 1 mol Na2CO3 to a beaker containing 100 mL deionized water and mix thoroughly by ultrasonication. This solution is denoted as solution B. Under stirring conditions, add solutions A and B dropwise to the beaker containing deionized water, maintaining the pH of the mixture at 9. After the addition is complete, transfer the mixture to a water bath, heat it to 60℃, and maintain the temperature for aging for 12 hours. After aging, filter and wash the precipitate. Place the precipitate in a vacuum dryer at 60℃ for 12 hours, then grind it to obtain BMgAl-LDH. The volume ratio of solution A, solution B and deionized water is 1:1:2.

[0041] Step B2: Add 2g BMgAl-LDH, 2.21g KH550 and 200mL 1,4-dioxane to a flask, stir at 90℃ for 6h, then lower the temperature to 15℃, add 1.84g cyanuric chloride and stir for 10min, then slowly add 1.01g triethylamine and continue stirring for 4h. After the reaction is complete, intermediate product 1 is obtained.

[0042] Step B3: Add dropwise a mixture of 0.01 mol ethylenediamine, 0.8 g NaOH and 200 mL deionized water to intermediate product 1, and heat to 50 °C and react for 2 h. Then raise the system temperature to 90 °C, add the same mixture dropwise again, and continue to reflux for 8 h. After the reaction is completed, lower to room temperature, filter, wash, and dry at 60 °C for 12 h to obtain intermediate product 2.

[0043] Step B4: Add 1g of intermediate product 2 and 0.01mol of NaOH to a reactor containing 30mL of anhydrous ethanol and stir until homogeneous. Then add 0.02mol of epichlorohydrin and stir for 2h. After the reaction is complete, distill under reduced pressure. Then slowly add 10mL of 25wt% NaOH solution to the mixture and heat to 80℃ for 3h. After the reaction is complete, filter, wash, and vacuum dry at 80℃ for 12h to obtain the terminal epoxy flame retardant.

[0044] Example 2

[0045] 1) The reinforcing filler is prepared by the following steps:

[0046] Step A1: Add 15 mL of 3-chloropropyltrimethoxysilane to a flask containing 100 mL of anhydrous ethanol and stir until homogeneous. Transfer the mixture to an oil bath and raise the system temperature to 65 °C. Slowly add 12 mL of dodecyl dimethyl tertiary amine at 200 rpm and continue stirring for 7 h. After the reaction is complete, cool to room temperature, distill under reduced pressure, and wash to obtain quaternary ammonium silane.

[0047] Step A2: Disperse 5g of nano-calcium carbonate ultrasonically into 30mL of anhydrous ethanol, add 3mL of toluene and mix well, then add 4mL of tridecafluorooctyltrimethoxysilane and 2.5g of quaternary ammonium salt silane. Stir the mixture at 30℃ for 6h. After the reaction is complete, centrifuge, wash and dry at 40℃ to obtain the reinforcing filler.

[0048] 2) The epoxy flame retardant is prepared by the following steps:

[0049] Step B1: Add 2 mol MgCl2·6H2O, 1 mol AlCl3·6H2O and 0.6 mol BCl3 to a beaker containing 100 mL deionized water and mix thoroughly by ultrasonication. This solution is denoted as solution A. Add 3 mol NaOH and 1 mol Na2CO3 to a beaker containing 100 mL deionized water and mix thoroughly by ultrasonication. This solution is denoted as solution B. Under stirring conditions, add solutions A and B dropwise to a beaker containing deionized water, maintaining the pH of the mixture at 9.5. After the addition is complete, transfer the mixture to a water bath, heat it to 60℃, and maintain the temperature for aging for 12 hours. After aging, filter and wash the precipitate. Place the precipitate in a vacuum dryer at 60℃ for 12 hours, then grind it to obtain BMgAl-LDH. The volume ratio of solution A, solution B and deionized water is 1:1:2.

[0050] Step B2: Add 2.5g BMgAl-LDH, 3.32g KH550 and 200mL 1,4-dioxane to a flask, stir at 90℃ for 6h, then lower the temperature to 15℃, add 2.76g cyanuric chloride and stir for 10min, then slowly add 1.5g triethylamine and continue stirring for 4h. After the reaction is complete, intermediate product 1 is obtained.

[0051] Step B3: Add dropwise a mixture of 0.01 mol ethylenediamine, 0.8 g NaOH and 200 mL deionized water to intermediate product 1, and heat to 50 °C and react for 2 h. Then raise the system temperature to 90 °C, add the same mixture dropwise again, and continue to reflux for 8 h. After the reaction is completed, lower to room temperature, filter, wash, and dry at 60 °C for 12 h to obtain intermediate product 2.

[0052] Step B4: Add 1.5g of intermediate product 2 and 0.015mol of NaOH to a reactor containing 40mL of anhydrous ethanol and stir until homogeneous. Then add 0.03mol of epichlorohydrin and stir for 2.5h. After the reaction is complete, distill under reduced pressure. Then slowly add 15mL of 25wt% NaOH solution to the mixture and heat to 80℃ for 3h. After the reaction is complete, filter, wash, and vacuum dry at 80℃ for 12h to obtain the terminal epoxy flame retardant.

[0053] Example 3

[0054] 1) The reinforcing filler is prepared by the following steps:

[0055] Step A1: Add 20 mL of 3-chloropropyltrimethoxysilane to a flask containing 100 mL of anhydrous ethanol and stir until homogeneous. Transfer the mixture to an oil bath and raise the system temperature to 65 °C. Slowly add 15 mL of dodecyl dimethyl tertiary amine at 200 rpm and continue stirring for 8 hours. After the reaction is complete, cool to room temperature, distill under reduced pressure, and wash to obtain quaternary ammonium silane.

[0056] Step A2: Disperse 5g of nano-calcium carbonate ultrasonically into 30mL of anhydrous ethanol, add 4mL of toluene and mix well, then add 5mL of tridecafluorooctyltrimethoxysilane and 3g of quaternary ammonium salt silane. Stir the mixture at 30℃ for 7h. After the reaction is complete, centrifuge, wash and dry at 40℃ to obtain the reinforcing filler.

[0057] 2) The epoxy flame retardant is prepared by the following steps:

[0058] Step B1: Add 2 mol MgCl2·6H2O, 1 mol AlCl3·6H2O, and 1 mol BCl3 to a beaker containing 100 mL of deionized water and mix thoroughly by ultrasonication. This solution is denoted as solution A. Add 3 mol NaOH and 1 mol Na2CO3 to a beaker containing 100 mL of deionized water and mix thoroughly by ultrasonication. This solution is denoted as solution B. Under stirring conditions, add solutions A and B dropwise to the beaker containing deionized water, maintaining the pH of the mixture at 10. After the addition is complete, transfer the mixture to a water bath, heat it to 60°C, and maintain the temperature for aging for 12 hours. After aging, filter and wash the mixture. Place the precipitate in a vacuum dryer at 60°C for 12 hours, then grind it to obtain BMgAl-LDH. The volume ratio of solution A, solution B, and deionized water is 1:1:2.

[0059] Step B2: Add 3g BMgAl-LDH, 4.42g KH550 and 200mL 1,4-dioxane to a flask, stir at 90℃ for 6h, then lower the temperature to 15℃, add 3.68g cyanuric chloride and stir for 10min, then slowly add 2.02g triethylamine and continue stirring for 4h. After the reaction is complete, intermediate product 1 is obtained.

[0060] Step B3: Add dropwise a mixture of 0.01 mol ethylenediamine, 0.8 g NaOH and 200 mL deionized water to intermediate product 1, and heat to 50 °C and react for 2 h. Then raise the system temperature to 90 °C, add the same mixture dropwise again, and continue to reflux for 8 h. After the reaction is completed, lower to room temperature, filter, wash, and dry at 60 °C for 12 h to obtain intermediate product 2.

[0061] Step B4: Add 2g of intermediate product 2 and 0.02mol NaOH to a reactor containing 50mL of anhydrous ethanol and stir until homogeneous. Then add 0.04mol of epichlorohydrin and stir for 3h. After the reaction is complete, distill under reduced pressure. Then slowly add 20mL of 25wt% NaOH solution to the mixture and heat to 80℃ for 3h. After the reaction is complete, filter, wash, and vacuum dry at 80℃ for 12h to obtain the terminal epoxy flame retardant.

[0062] Example 4

[0063] A molded wood-plastic composite flooring includes a base layer and a reinforcing layer, which are bonded together by diphenylmethane diisocyanate. The flooring has rounded edges and a locking structure around its perimeter, and the flooring can be interlocked with each other through the locking structure.

[0064] After the floorboards are interlocked together by a locking structure, a γ-shaped double arc structure is formed at the joint.

[0065] The arc edge is the same color as the surface of the floor body and is continuous as a whole;

[0066] Its production process includes the following steps:

[0067] After the floorboards are interlocked together by a locking structure, a γ-shaped double arc structure is formed at the joint.

[0068] The arc edge is the same color as the surface of the floor body and is continuous as a whole;

[0069] The substrate layer is a PVC board, which includes, by weight: 100 parts of PVC resin powder type 5, 3 parts of calcium zinc stabilizer, 0.8 parts of plasticizer DOTP, and 15 parts of reinforcing filler prepared in Example 1;

[0070] The reinforcing layer is a wood-plastic composite board, which, by weight, includes: 70 parts of PVC resin powder type 5, 80 parts of PVC resin powder type 7, 50 parts of plant fiber, 5 parts of calcium-zinc stabilizer, 3 parts of the end-epoxy flame retardant prepared in Example 1, 20 parts of the reinforcing filler prepared in Example 1, 1 part of oxidized wax, 0.8 parts of white foaming agent, 0.8 parts of yellow foaming agent, 2 parts of foaming regulator ZB-530, and 0.5 parts of triethylamine.

[0071] Step S1: Weigh the raw materials according to the weight proportions, stir the PVC resin powder type 5, calcium zinc stabilizer, plasticizer DOTP and the reinforcing filler prepared in Example 1 at 130°C and 700 rpm for 30 min, then extrude the mixture at an extrusion temperature of 150°C, an extrusion speed of 140 rpm / min and an extrusion pressure of 5 MPa, and then cool and set it to obtain PVC sheet.

[0072] Step S2: Weigh the raw materials according to the weight proportions, mix PVC resin powder type 5, PVC resin powder type 7 and plant fiber evenly, add calcium zinc stabilizer, end epoxy flame retardant prepared in Example 1, reinforcing filler prepared in Example 1, oxidized wax, white foaming agent, yellow foaming agent, foaming regulator ZB-530 and triethylamine, stir at 140℃ and 800rpm for 40min, then extrude the mixture at an extrusion temperature of 180℃, an extrusion speed of 150rpm / min and an extrusion pressure of 5MPa, and cool and set to obtain wood-plastic composite board;

[0073] Step S3: Apply adhesive evenly to the upper surface of the PVC board and bond it to the wood-plastic composite board. After bonding, mold and cut to obtain the molded wood-plastic composite flooring. The molding process is carried out at a temperature of 30℃, a pressure of 10MPa, and a time of 60s.

[0074] Example 5

[0075] A molded wood-plastic composite flooring includes a base layer and a reinforcing layer, which are bonded together by diphenylmethane diisocyanate. The flooring has rounded edges and a locking structure around its perimeter, and the flooring can be interlocked with each other through the locking structure.

[0076] After the floorboards are interlocked together by a locking structure, a γ-shaped double arc structure is formed at the joint.

[0077] The arc edge is the same color as the surface of the floor body and is continuous as a whole;

[0078] Its production process includes the following steps:

[0079] The substrate layer is a PVC board, which includes, by weight: 100 parts of PVC resin powder type 5, 3.5 parts of calcium zinc stabilizer, 1.2 parts of plasticizer DOTP, and 20 parts of reinforcing filler prepared in Example 2;

[0080] The reinforcing layer is a wood-plastic composite board, comprising, by weight: 80 parts of PVC resin powder type 5, 85 parts of PVC resin powder type 7, 55 parts of plant fiber, 8 parts of calcium-zinc stabilizer, 5 parts of end-epoxy flame retardant prepared in Example 2, 30 parts of reinforcing filler prepared in Example 2, 1.5 parts of oxidized wax, 0.9 parts of white foaming agent, 0.9 parts of yellow foaming agent, 2.5 parts of foaming regulator ZB-530, and 1 part of triethylamine;

[0081] Step S1: Weigh the raw materials according to the weight proportions, stir the PVC resin powder type 5, calcium zinc stabilizer, plasticizer DOTP and the reinforcing filler prepared in Example 2 at 140°C and 800 rpm for 30 min, then extrude the mixture at an extrusion temperature of 160°C, an extrusion speed of 150 rpm / min and an extrusion pressure of 6 MPa, and then cool and set it to obtain PVC sheet.

[0082] Step S2: Weigh the raw materials according to the weight proportions, mix PVC resin powder type 5, PVC resin powder type 7 and plant fiber evenly, add calcium zinc stabilizer, end epoxy flame retardant prepared in Example 2, reinforcing filler prepared in Example 2, oxidized wax, white foaming agent, yellow foaming agent, foaming regulator ZB-530 and triethylamine, stir at 145℃ and 850rpm for 40min, then extrude the mixture at an extrusion temperature of 190℃, an extrusion speed of 160rpm / min and an extrusion pressure of 6MPa, and cool and set it to obtain wood-plastic composite board;

[0083] Step S3: Apply adhesive evenly to the upper surface of the PVC board and bond it to the wood-plastic composite board. After bonding, mold and cut to obtain the molded wood-plastic composite flooring. The molding process is carried out at a temperature of 35℃, a pressure of 11MPa, and a time of 60s.

[0084] Example 6

[0085] A molded wood-plastic composite flooring includes a base layer and a reinforcing layer, which are bonded together by diphenylmethane diisocyanate. The flooring has rounded edges and a locking structure around its perimeter, and the flooring can be interlocked with each other through the locking structure.

[0086] After the floorboards are interlocked together by a locking structure, a γ-shaped double arc structure is formed at the joint.

[0087] The arc edge is the same color as the surface of the floor body and is continuous as a whole;

[0088] Its production process includes the following steps:

[0089] The substrate layer is a PVC board, which includes, by weight: 100 parts of PVC resin powder type 5, 4 parts of calcium zinc stabilizer, 2 parts of plasticizer DOTP, and 25 parts of reinforcing filler prepared in Example 3.

[0090] The reinforcing layer is a wood-plastic composite board, which, by weight, includes: 90 parts of PVC resin powder type 5, 90 parts of PVC resin powder type 7, 60 parts of plant fiber, 11 parts of calcium-zinc stabilizer, 7 parts of end-epoxy flame retardant prepared in Example 3, 40 parts of reinforcing filler prepared in Example 3, 2 parts of oxidized wax, 1 part of white foaming agent, 1 part of yellow foaming agent, 3 parts of foaming regulator ZB-530, and 1.5 parts of triethylamine.

[0091] Step S1: Weigh the raw materials according to the weight proportions, stir the PVC resin powder type 5, calcium zinc stabilizer, plasticizer DOTP and the reinforcing filler prepared in Example 3 at 150°C and 900 rpm for 30 min, then extrude the mixture at an extrusion temperature of 170°C, an extrusion speed of 160 rpm / min and an extrusion pressure of 7 MPa, and then cool and set it to obtain PVC sheet.

[0092] Step S2: Weigh the raw materials according to the weight proportions, mix PVC resin powder type 5, PVC resin powder type 7 and plant fiber evenly, add calcium zinc stabilizer, end epoxy flame retardant prepared in Example 3, reinforcing filler prepared in Example 3, oxidized wax, white foaming agent, yellow foaming agent, foaming regulator ZB-530 and triethylamine, stir at 150℃ and 900rpm for 40min, then extrude the mixture at an extrusion temperature of 200℃, an extrusion speed of 170rpm / min and an extrusion pressure of 7MPa, and cool and set to obtain wood-plastic composite board;

[0093] Step S3: Apply adhesive evenly to the upper surface of the PVC board and bond it to the wood-plastic composite board. After bonding, mold and cut to obtain the molded wood-plastic composite flooring. The molding process is carried out at a temperature of 40℃, a pressure of 12MPa, and a time of 60s.

[0094] Comparative Example 1

[0095] This comparative example is a wood-plastic composite flooring, which differs from Example 6 in that an equal amount of nano-calcium carbonate is used instead of the reinforcing filler prepared in Example 3, while all other aspects are the same.

[0096] Comparative Example 2

[0097] This comparative example is a wood-plastic composite flooring, which differs from Example 6 in that an equal amount of ammonium polyphosphate flame retardant is used instead of the end-epoxy flame retardant prepared in Example 3, while all other aspects are the same.

[0098] The wood-plastic composite flooring prepared in Examples 4-6 and Comparative Examples 1-2 was tested for flame retardancy, mechanical properties, and water absorption. Flame retardancy testing was conducted according to EN 13501 for flame retardancy detection and grading. Bending strength testing was performed according to section 4.7 of GB / T 17657-2013, "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels". Water absorption testing was performed according to section 4.6 of GB / T 17657-2013, with an immersion time of (72±0.5) h. The test results are shown in the table below.

[0099] Flame retardant rating Flexural strength MPa Water absorption rate % Example 4 A1 46 0.15 Example 5 A1 48 0.14 Example 6 A1 50 0.11 Comparative Example 1 A1 26 0.36 Comparative Example 2 B 39 0.13

[0100] As can be seen from the table above, the molded wood-plastic composite flooring provided by the present invention has excellent flame retardant properties, high bending strength and low water absorption.

[0101] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. A molded wood-plastic composite flooring, characterized in that, It includes a base layer and a reinforcing layer, which are bonded together by an adhesive. The floor has rounded edges and a locking structure around its perimeter, and the floorboards can be interlocked together using the locking structure. The substrate layer is a PVC sheet, which includes, by weight: 100 parts of PVC resin powder type 5, 3-4 parts of heat stabilizer, 0.8-2 parts of plasticizer, and 15-25 parts of reinforcing filler; The reinforcing layer is a wood-plastic composite board, comprising, by weight: 70-90 parts of PVC resin powder type 5, 80-90 parts of PVC resin powder type 7, 50-60 parts of plant fiber, 5-11 parts of heat stabilizer, 3-7 parts of end-epoxy flame retardant, 20-40 parts of reinforcing filler, 1-2 parts of lubricant, 0.8-1 part of white foaming agent, 0.8-1 part of yellow foaming agent, 2-3 parts of foaming regulator, and 0.5-1.5 parts of catalyst; The reinforcing filler is prepared by the following steps: Step A1: Add 3-chloropropyltrimethoxysilane to a flask containing anhydrous ethanol and stir until homogeneous. Transfer the mixture to an oil bath and raise the system temperature to 65°C. Slowly add dodecyl dimethyl tertiary amine at 200 rpm and continue stirring for 6-8 hours. After the reaction is complete, cool to room temperature, distill under reduced pressure, and wash to obtain quaternary ammonium silane. Step A2: Disperse nano-calcium carbonate in anhydrous ethanol by ultrasonication, add toluene dropwise and mix well, then add tridecafluorooctyltrimethoxysilane and quaternary ammonium salt silane. Stir the mixture at 30°C for 5-7 hours. After the reaction is complete, centrifuge, wash and dry at 40°C to obtain the reinforcing filler.

2. The molded wood-plastic composite flooring according to claim 1, characterized in that, After the floorboards are interlocked together by the aforementioned locking structure, a γ-shaped double arc structure is formed at the joint.

3. The molded wood-plastic composite flooring according to claim 1, characterized in that, The arc edge is the same color as the surface of the floor body and is continuous as a whole.

4. The molded wood-plastic composite flooring according to claim 1, characterized in that, The terminal epoxy flame retardant is prepared by the following steps: Step B1: Add MgCl2·6H2O, AlCl3·6H2O and BCl3 to a beaker containing deionized water and mix thoroughly by ultrasonication. This mixture is labeled as solution A. Add NaOH and Na2CO3 to a beaker containing deionized water and mix thoroughly by ultrasonication. This mixture is labeled as solution B. Under stirring conditions, add solutions A and B dropwise to the beaker containing deionized water and maintain the pH of the mixture at 9-10. After the addition is complete, transfer the mixture to a water bath and heat it to 60℃. Maintain the temperature for aging for 12 hours. After aging, filter and wash the mixture. Place the precipitate in a vacuum dryer at 60℃ for 12 hours and grind it to obtain BMgAl-LDH. Step B2: Add BMgAl-LDH, KH550 and 1,4-dioxane to a flask, stir and react at 90°C for 6 hours, then lower the temperature to 15°C, add cyanuric chloride and stir for 10 minutes, then slowly add triethylamine and continue stirring for 4 hours. After the reaction is complete, intermediate product 1 is obtained. Step B3: Add a mixture of ethylenediamine, NaOH and deionized water dropwise to intermediate product 1, and heat to 50°C and react for 2 hours. Then raise the system temperature to 90°C, add the same mixture dropwise again, and continue to reflux for 8 hours. After the reaction is completed, lower to room temperature, filter, wash, and dry at 60°C for 12 hours to obtain intermediate product 2. Step B4: Add intermediate product 2 and NaOH to a reactor containing anhydrous ethanol and stir until homogeneous. Then add epichlorohydrin and stir for 2-3 hours. After the reaction is complete, distill under reduced pressure. Then slowly add 25wt% NaOH solution to the mixture and heat to 80℃ for 3 hours. After the reaction is complete, filter, wash, and vacuum dry at 80℃ for 12 hours to obtain the terminal epoxy flame retardant.

5. A molded wood-plastic composite flooring according to claim 4, characterized in that, In step B1, solutions A and B are added dropwise to a beaker containing deionized water. The volume ratio of solutions A, B, and deionized water is 1:1:

2. The volume ratio of MgCl2·6H2O, AlCl3·6H2O, BCl3, and deionized water in solution A is 2 mol: 1 mol: 0.2-1 mol: 100 mL. The volume ratio of NaOH, Na2CO3, and deionized water in solution B is 3 mol: 1 mol: 100 mL.

6. A molded wood-plastic composite flooring according to claim 4, characterized in that, In step B2, the ratio of BMgAl-LDH, KH550, 1,4-dioxane, cyanuric chloride, and triethylamine is 2-3 g. 2.21-4.42g: 200mL: 1.84-3.68g: 1.01-2.02g.

7. A molded wood-plastic composite flooring according to claim 4, characterized in that, In step B3, the ratio of ethylenediamine, NaOH, and deionized water in the mixture is 0.01 mol: 0.8 g: 200 mL.

8. A molded wood-plastic composite flooring according to claim 4, characterized in that, In step B4, the ratio of intermediate product 2, NaOH, anhydrous ethanol, epichlorohydrin and NaOH solution is 1-2g: 0.01-0.02mol: 30-50mL: 0.02-0.04mol: 10-20mL.

9. The manufacturing process of a molded wood-plastic composite flooring according to claim 1, characterized in that, Includes the following steps: Step S1: Weigh the raw materials according to the weight proportions, stir the PVC resin powder type 5, heat stabilizer, plasticizer and reinforcing filler at 130-150℃ and 700-900rpm for 30min, then extrude the mixture at an extrusion temperature of 150-170℃, an extrusion speed of 140-160rpm / min and an extrusion pressure of 5-7MPa, and then cool and set it to obtain PVC sheet. Step S2: Weigh the raw materials according to the weight proportions, mix PVC resin powder type 5, PVC resin powder type 7 and plant fiber evenly, then add heat stabilizer, end epoxy flame retardant, reinforcing filler, lubricant, white foaming agent, yellow foaming agent, foaming regulator and catalyst, and stir for 40 minutes at 140-150℃ and 800-900rpm. Then extrude the mixture at an extrusion temperature of 180-200℃, an extrusion speed of 150-170rpm / min and an extrusion pressure of 5-7MPa, and cool and solidify to obtain wood-plastic composite board. Step S3: Apply adhesive evenly to the upper surface of the PVC board and bond it to the wood-plastic composite board. After bonding, mold and cut to obtain the molded wood-plastic composite flooring.

10. The manufacturing process of a molded wood-plastic composite flooring according to claim 9, characterized in that, The adhesive used in step S3 is diphenylmethane diisocyanate, and the molding process is carried out at a temperature of 30-40°C, a pressure of 10-12 MPa, and a time of 60 seconds.