Fireproof high-strength plastic floor material and production process thereof

Abstract

The invention relates to the technical field of flooring materials, in particular to a fireproof high-strength plastic flooring material and a production process thereof. The fireproof high-strength plastic floor material is prepared from the following components in parts by weight: 45 to 65 parts of matrix resin, 20 to 30 parts of composite filler, 10 to 12 parts of acetyl tributyl citrate, 6 to 8 parts of calcium-zinc composite stabilizer, 6 to 9 parts of aluminum hypophosphite, 3 to 5 parts of nano silicon dioxide, 2 to 3 parts of maleic anhydride grafted POE (Polyolefin Elastomer), 1 to 2 parts of oxidized polyethlene wax, 0.5 to 1 part of antioxidant and 0.5 to 1 part of ultraviolet light absorber, wherein the composite filler is prepared from surface modified aluminum hydroxide, a compound layered silicate nano composite material and zinc borate coated calcium carbonate. According to the fireproof high-strength plastic floor material provided by the invention, the flame retardance of the plastic floor material is improved, and the strength, toughness, tear resistance, wear resistance and dimensional stability of the material are improved.

Description

Technical Field

[0001] This invention relates to the field of flooring materials technology, specifically to a fire-resistant high-strength plastic flooring material and its manufacturing process. Background Technology

[0002] Fire-resistant high-strength PVC flooring is a type of building decoration material with special properties, prepared through the rational selection and combination of various raw materials and specific production processes. Its core objective is to significantly improve the fire resistance and mechanical strength of the material while ensuring its basic performance, thereby reducing fire risk, extending the material's service life, and improving safety. Currently, the most common fire-resistant high-strength PVC flooring materials on the market use polyvinyl chloride (PVC) as the base resin due to its good processing performance, chemical stability, and certain flame retardancy. To further enhance the material's fire resistance and mechanical properties, inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide, as well as inorganic fillers such as calcium carbonate, are usually added to enhance the material's hardness and rigidity. Simultaneously, various additives, such as stabilizers, plasticizers, and antioxidants, are also added to improve the material's processing performance and stability.

[0003] Although inorganic flame retardants such as aluminum hydroxide are added to existing materials, the dispersion of these flame retardants in the material is often not ideal, resulting in uneven flame retardant effects. Moreover, the mechanism of action of a single flame retardant is relatively simple, making it difficult to effectively prevent the spread of flames and the transfer of heat in complex fire environments. Inorganic fillers used in existing materials, such as calcium carbonate, while increasing the hardness and rigidity of the material, have poor compatibility with the matrix resin, easily forming interface defects within the material, leading to stress concentration and reducing the material's tear resistance, abrasion resistance, and dimensional stability. During long-term use, these defects gradually expand, causing problems such as cracking and deformation, seriously affecting the service life and safety of the PVC flooring. Based on this, this invention proposes a fire-resistant high-strength PVC flooring material and its manufacturing process. Summary of the Invention

[0004] This invention proposes a fire-resistant high-strength plastic flooring material and its production process, which improves the flame retardancy of the plastic flooring material, enhances its strength, toughness, tear resistance, abrasion resistance and dimensional stability, and reduces the loss of mechanical and abrasion properties caused by weak interfaces.

[0005] The technical solution of the present invention is as follows: In a first aspect, the present invention proposes a fire-resistant high-strength plastic flooring material, comprising, by weight, the following components: 45-65 parts of matrix resin, 20-30 parts of composite filler, 10-12 parts of tributyl acetylacetonate, 6-8 parts of calcium-zinc composite stabilizer, 6-9 parts of aluminum hypophosphite, 3-5 parts of nano-silica; 2-3 parts of maleic anhydride-grafted POE, 1-2 parts of oxidized polyethylene wax, 0.5-1 part of antioxidant, and 0.5-1 part of ultraviolet absorber; wherein the composite filler is composed of surface-modified aluminum hydroxide, compounded layered silicate nanocomposite material, and zinc borate-coated calcium carbonate; and the matrix resin is composed of a copolymer of polyvinyl chloride and ethylene-vinyl acetate in a weight ratio of 3.5-5:1.

[0006] As a further technical solution, the preparation method of the surface-modified aluminum hydroxide includes: preheating aluminum hydroxide powder to 70-85°C, spraying a solution of silane coupling agent KH-570 diluted with anhydrous ethanol into the powder in atomized form under high-speed stirring, controlling the reaction temperature at 85-90°C and stirring continuously for 15-25 minutes, and then cooling and discharging the powder to obtain the surface-modified aluminum hydroxide.

[0007] As a further technical solution, the amount of the silane coupling agent KH-570 added is 1.0%-1.5% of the weight of the aluminum hydroxide powder.

[0008] As a further technical solution, the composite layered silicate nanocomposite material includes organo-modified montmorillonite and nano-sepiolite in a weight ratio of 1:1.8-2.2.

[0009] As a further technical solution, the method for preparing zinc borate-coated calcium carbonate includes: A1. Dispersion: Calcium carbonate, deionized water and sodium polyacrylate dispersant are mixed and ultrasonically dispersed to obtain suspension A; A2. Preparation of reaction solution: Prepare a mixed aqueous solution containing zinc source and boron source B; A3. Coating reaction: Under conditions of 55-65℃ and continuous stirring, the mixed aqueous solution B is added dropwise to the suspension A. After the addition is complete, the reaction is kept at the temperature for 1.5-2.5 hours, and the pH of the system is adjusted to 8.0-9.0. A4. Post-processing: After the reaction is completed, solid-liquid separation is performed. The obtained solid is washed, dried at 100-110℃ for 10-14 hours, and then sieved to obtain the zinc borate-coated calcium carbonate.

[0010] As a further technical solution, the weight ratio of calcium carbonate, deionized water and sodium polyacrylate is 20:180-220:0.1-0.3.

[0011] As a further technical solution, the weight ratio of the calcium carbonate, the zinc source and the boron source is 100:13-18:11-16.

[0012] As a further technical solution, the antioxidant is antioxidant 1010; the ultraviolet absorber is ultraviolet absorber UV-326.

[0013] Secondly, this invention proposes a production process for a fire-resistant, high-strength plastic flooring material, comprising the following steps: S1. Raw material pretreatment: Surface-modified aluminum hydroxide, composite layered silicate nanocomposite material and zinc borate-coated calcium carbonate were prepared respectively; S2. Filler premixing: The surface-modified aluminum hydroxide, the compounded layered silicate nanocomposite material, and the zinc borate-coated calcium carbonate are blended to obtain a composite filler. The composite filler, aluminum hypophosphite, and nano silica are premixed in a high-speed mixer at 60-80°C for 10-25 minutes to obtain a premixed filler. S3. Main ingredient mixing: Add polyvinyl chloride, ethylene-vinyl acetate copolymer, calcium-zinc composite stabilizer, antioxidant and ultraviolet absorber to a high-speed mixer, heat to 95-105℃ and stir for 5-8 minutes; cool to 75-85℃, add acetylated tributyl citrate and maleic anhydride-grafted POE, stir for 3-5 minutes; add the premixed filler obtained in step S2, stir at high speed until the material temperature reaches 110-115℃; add oxidized polyethylene wax, stir for 2-3 minutes and then cool to below 45℃ to obtain the premix; S4. Melt blending and granulation: The premixed material is fed into a parallel co-rotating twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the fire-resistant high-strength plastic flooring material is obtained.

[0014] As a further technical solution, in step S4, the process parameters of the parallel co-rotating twin-screw extruder are as follows: screw speed 200-300 rpm; extrusion temperature settings from the feed inlet to the die head are: feeding zone 130-140℃, melting zone 155-175℃, mixing zone 170-180℃, homogenizing zone 175-180℃, and die head 170-175℃.

[0015] The working principle and beneficial effects of this invention are as follows: The composite filler in this fire-retardant high-strength plastic flooring material consists of surface-modified aluminum hydroxide, a compounded layered silicate nanocomposite material, and zinc borate-coated calcium carbonate. These components work synergistically to enhance the material's flame retardancy and mechanical properties. The surface-modified aluminum hydroxide, treated with a silane coupling agent, exhibits excellent interfacial bonding with the matrix, providing not only highly efficient flame retardancy but also improved strength and toughness. The compounded layered silicate nanocomposite material, with its combination of organo-modified montmorillonite and nano-sepiolite, significantly improves the material's tear resistance, abrasion resistance, and dimensional stability. Zinc borate-coated calcium carbonate acts as a multifunctional synergist; zinc borate provides condensed-phase flame retardancy and smoke suppression, while the coating structure improves the compatibility of calcium carbonate with the matrix, reducing losses in mechanical and abrasion resistance due to weak interfaces. The synergistic effect of these three components results in excellent flame retardancy and mechanical properties.

[0016] The flame-retardant system of this invention consists of multiple components that work synergistically to exert their flame-retardant effect. Surface-modified aluminum hydroxide and aluminum hypophosphite serve as the main flame retardants. Surface-modified aluminum hydroxide decomposes and absorbs heat during combustion, lowering the material temperature and releasing water vapor to dilute combustible gases. Aluminum hypophosphite can exert its flame-retardant effect in both the condensed and gas phases, promoting char formation and preventing heat and oxygen transfer. Zinc borate coating on calcium carbonate provides condensed-phase flame retardancy and smoke suppression, synergistically enhancing the synergistic effect of the flame-retardant system with surface-modified aluminum hydroxide and aluminum hypophosphite, thereby improving the flame retardancy of the material. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] It should also be noted that the following components are used: polyvinyl chloride (PVC), model SG-8, K value 60; ethylene-vinyl acetate copolymer, model EVA 40W; calcium-zinc composite stabilizer, model SAK-CZL39-NP; nano-silica, particle size 40-120nm; maleic anhydride-grafted POE, model CMG5805-L; oxidized polyethylene wax, model AC629A; and organomodified montmorillonite, particle size 14-20μ4. The organomodified montmorillonite is modified with a cationic surfactant, the modifier being CH3(CH2). 17 N(CH3)[(CH2CH2OH)2] + Nano sepiolite was purchased from Xiangtan Yuanyuan Sepiolite Co., Ltd.; calcium carbonate is light calcium carbonate with an average particle size of 2μm; aluminum hydroxide has an average particle size of 150 mesh.

[0019] Example 1 This embodiment provides a fire-resistant high-strength plastic flooring material, which, by weight, comprises the following components: 42 parts polyvinyl chloride, 10.5 parts ethylene-vinyl acetate copolymer, 11 parts tributyl acetyl citrate, 7 parts calcium-zinc composite stabilizer, 7.5 parts aluminum hypophosphite, 4 parts nano silica, 2.5 parts maleic anhydride-grafted POE, 1.5 parts oxidized polyethylene wax, 0.8 parts antioxidant 1010, 0.7 parts ultraviolet absorber UV-326, and 25 parts composite filler; The composite filler consists of 15 parts of surface-modified aluminum hydroxide, 5 parts of compounded layered silicate nanocomposite material, and 5 parts of zinc borate-coated calcium carbonate; wherein, the compounded layered silicate nanocomposite material is composed of organomodified montmorillonite and nano-sepiolite in a weight ratio of 1:2. The preparation method of surface-modified aluminum hydroxide includes: taking 15 kg of 150-mesh aluminum hydroxide powder and placing it in a high-speed mixer preheated to 80°C; diluting silane coupling agent KH-570 (at a dosage of 1.2% of the weight of the aluminum hydroxide powder) with twice its weight of anhydrous ethanol to obtain a modifier solution; uniformly spraying the modifier solution onto the powder in an atomizing manner at a speed of 800 rpm; after spraying, controlling the temperature at 88±2°C and continuously stirring at 800 rpm for 20 minutes; then cooling to below 50°C and discharging to obtain surface-modified aluminum hydroxide; The preparation methods for zinc borate-coated calcium carbonate include: A1. Dispersion: Weigh 5 kg of light calcium carbonate with an average particle size of 2 μm, 50 kg of deionized water, and 12.5 g of sodium polyacrylate dispersant (0.25% of the weight of calcium carbonate), add them to the reaction vessel, and disperse them by ultrasonication (1 kW power) at 300 rpm for 30 minutes to obtain suspension A; A2. Preparation of reaction solution: Weigh 0.78 kg of zinc sulfate heptahydrate and 0.65 kg of sodium tetraborate decahydrate, respectively, and dissolve them in 10 kg of deionized water to obtain mixed aqueous solution B; A3. Coating reaction: Heat suspension A to 60°C and keep stirring at 200 rpm. Slowly and evenly add mixed aqueous solution B to suspension A over 1 hour. After the addition is complete, continue the reaction at 60°C for 2 hours. During the reaction, add dilute ammonia to maintain the pH of the system at around 8.5. A4. Post-processing: After the reaction is complete, filter the solution and wash the filter cake with deionized water until the conductivity of the filtrate is basically constant. Dry the obtained solid at 105℃ for 12 hours, pulverize it and pass it through a 400-mesh sieve to obtain zinc borate coated calcium carbonate. The preparation method of the composite layered silicate nanocomposite material includes: weighing organo-modified montmorillonite and nano-sepiolite in a weight ratio of 1:2, stirring and mixing them at 200 rpm for 30 minutes in a low-speed mixer at room temperature until they are homogeneous, and then obtaining the composite material. The production process of the fire-resistant high-strength plastic flooring material in this embodiment includes the following steps: S1. Raw material pretreatment: Surface-modified aluminum hydroxide, zinc borate-coated calcium carbonate, and composite layered silicate nanocomposites were prepared respectively; S2. Filler premixing: Surface-modified aluminum hydroxide, zinc borate-coated calcium carbonate, and compounded layered silicate nanocomposite materials are blended to obtain composite filler. The composite filler, aluminum hypophosphite, and nano silica are added to a high-speed mixer and stirred at 70°C and 600 rpm for 20 minutes to obtain premixed filler. S3. Main ingredient mixing: Polyvinyl chloride, ethylene-vinyl acetate copolymer, calcium-zinc composite stabilizer, antioxidant 1010 and ultraviolet absorber UV-326 are added to a high-speed mixer, heated to 100℃ and stirred at 800 rpm for 6 minutes; cooled to 80℃, acetylated tributyl citrate and maleic anhydride-grafted POE are added, and stirred at 600 rpm for 4 minutes; the premixed filler obtained in step S2 is added, and the speed is increased to 1000 rpm and stirred until the material temperature rises to about 112℃; oxidized polyethylene wax is added, and stirring is continued at 1000 rpm for 2.5 minutes; the mixed material is discharged into a cold mixer and cooled to below 40℃ to obtain the premix. S4. Melt Blending and Granulation: The premixed material is fed into a parallel co-rotating twin-screw extruder with a screw diameter of 52 mm, a length-to-diameter ratio of 40:1, and a screw speed of 250 rpm. The extrusion temperatures are set sequentially from the feed inlet to the die head as follows: feeding zone 135℃, melting zone 165℃, mixing zone 175℃, homogenization zone 178℃, and die head 172℃. After melt blending, the material is extruded, cooled in a water bath, dried by an air knife, and then granulated to obtain particles with a particle size of approximately 3 mm × 3 mm, which is the fire-resistant high-strength plastic flooring material.

[0020] Example 2 This embodiment provides a fire-resistant high-strength plastic flooring material, which, by weight, comprises the following components: 52 parts polyvinyl chloride, 10.4 parts ethylene-vinyl acetate copolymer, 10 parts tributyl acetyl citrate, 6 parts calcium-zinc composite stabilizer, 6 parts aluminum hypophosphite, 3 parts nano silica, 2 parts maleic anhydride-grafted POE, 1 part oxidized polyethylene wax, 0.5 parts antioxidant 1010, 0.5 parts ultraviolet absorber UV-326, and 20 parts composite filler; The composite filler consists of 12 parts of surface-modified aluminum hydroxide, 4 parts of compounded layered silicate nanocomposite material, and 4 parts of zinc borate-coated calcium carbonate; wherein, the compounded layered silicate nanocomposite material is composed of organomodified montmorillonite and nano-sepiolite in a weight ratio of 1:1.8. The preparation method of surface-modified aluminum hydroxide includes: taking 12 kg of 150-mesh aluminum hydroxide powder and placing it in a high-speed mixer preheated to 70°C; diluting silane coupling agent KH-570 (at a dosage of 1.0% of the weight of the aluminum hydroxide powder) with twice its weight of anhydrous ethanol to obtain a modifier solution; uniformly spraying the modifier solution onto the powder in an atomizing manner at a speed of 800 rpm; after spraying, controlling the temperature at 85±2°C and continuously stirring the reaction at 800 rpm for 15 minutes; then cooling to below 50°C and discharging to obtain surface-modified aluminum hydroxide; The preparation methods for zinc borate-coated calcium carbonate include: A1. Dispersion: Weigh 4 kg of light calcium carbonate with an average particle size of 2 μm, 48 kg of deionized water, and 4 g of sodium polyacrylate dispersant (0.1% of the weight of calcium carbonate), add them to the reaction vessel, and disperse them by ultrasonication (1 kW power) at 300 rpm for 30 minutes to obtain suspension A; A2. Preparation of reaction solution: Weigh 0.52 kg of zinc sulfate heptahydrate and 0.44 kg of sodium tetraborate decahydrate, respectively, and dissolve them in 10 kg of deionized water to obtain mixed aqueous solution B; A3. Coating reaction: Heat suspension A to 55°C and stir at 200 rpm. Slowly and evenly add mixed aqueous solution B to suspension A over 1 hour. After the addition is complete, continue the reaction at 55°C for 1.5 hours. During the reaction, add dilute ammonia to maintain the pH of the system at around 8.0. A4. Post-processing: After the reaction is complete, filter the mixture and wash the filter cake with deionized water until the conductivity of the filtrate is basically constant. Dry the obtained solid at 100℃ for 10 hours, pulverize it and pass it through a 400-mesh sieve to obtain zinc borate coated calcium carbonate. The preparation method of the composite layered silicate nanocomposite material includes: weighing organo-modified montmorillonite and nano-sepiolite at a weight ratio of 1:1.8, stirring and mixing them at 200 rpm for 30 minutes in a low-speed mixer at room temperature until they are homogeneous, and then obtaining the composite material. The production process of the fire-resistant high-strength plastic flooring material in this embodiment includes the following steps: S1. Raw material pretreatment: Surface-modified aluminum hydroxide, zinc borate-coated calcium carbonate, and composite layered silicate nanocomposites were prepared respectively; S2. Filler premixing: Surface-modified aluminum hydroxide, zinc borate-coated calcium carbonate, and compounded layered silicate nanocomposite materials are blended to obtain composite filler. The composite filler, aluminum hypophosphite, and nano silica are added to a high-speed mixer and stirred at 60°C and 600 rpm for 10 minutes to obtain premixed filler. S3. Main ingredient mixing: Polyvinyl chloride, ethylene-vinyl acetate copolymer, calcium-zinc composite stabilizer, antioxidant 1010 and ultraviolet absorber UV-326 are added to a high-speed mixer, heated to 95°C and stirred at 800 rpm for 5 minutes; cooled to 75°C, acetylated tributyl citrate and maleic anhydride-grafted POE are added, and stirred at 600 rpm for 3 minutes; the premixed filler obtained in step S2 is added, and the speed is increased to 1000 rpm and stirred until the material temperature reaches about 110°C; oxidized polyethylene wax is added, and stirring is continued at 1000 rpm for 2 minutes; the mixed material is discharged into a cold mixer and cooled to below 40°C to obtain the premix. S4. Melt Blending and Granulation: The premixed material is fed into a parallel co-rotating twin-screw extruder with a screw diameter of 52 mm, a length-to-diameter ratio of 40:1, and a screw speed of 200 rpm. The extrusion temperatures are set sequentially from the feed inlet to the die head as follows: feeding zone 130℃, melting zone 155℃, mixing zone 170℃, homogenization zone 175℃, and die head 170℃. After melt blending, the material is extruded, cooled in a water bath, dried by an air knife, and then granulated to obtain particles with a particle size of approximately 3 mm × 3 mm, which is the fire-resistant high-strength plastic flooring material.

[0021] Example 3 This embodiment provides a fire-resistant high-strength plastic flooring material, which, by weight, comprises the following components: 54 parts polyvinyl chloride, 11 parts ethylene-vinyl acetate copolymer, 12 parts tributyl acetyl citrate, 8 parts calcium-zinc composite stabilizer, 9 parts aluminum hypophosphite, 5 parts nano silica, 3 parts maleic anhydride-grafted POE, 2 parts oxidized polyethylene wax, 1 part antioxidant 1010, 1 part ultraviolet absorber UV-326, and 30 parts composite filler. The composite filler consists of 18 parts of surface-modified aluminum hydroxide, 6 parts of compounded layered silicate nanocomposite material, and 6 parts of zinc borate-coated calcium carbonate; wherein, the compounded layered silicate nanocomposite material is composed of organomodified montmorillonite and nano-sepiolite in a weight ratio of 1:2.2. The preparation method of surface-modified aluminum hydroxide includes: taking 18 kg of 150-mesh aluminum hydroxide powder and placing it in a high-speed mixer preheated to 85°C; diluting silane coupling agent KH-570 (at a dosage of 1.5% of the weight of the aluminum hydroxide powder) with twice its weight of anhydrous ethanol to obtain a modifier solution; uniformly spraying the modifier solution onto the powder in an atomizing manner at a speed of 800 rpm; after spraying, controlling the temperature at 90±2°C and continuously stirring at 800 rpm for 25 minutes; then cooling to below 50°C and discharging to obtain surface-modified aluminum hydroxide; The preparation methods for zinc borate-coated calcium carbonate include: A1. Dispersion: Weigh 6 kg of light calcium carbonate with an average particle size of 2 μm, 66 kg of deionized water, and 18 g of sodium polyacrylate dispersant (0.3% of the weight of calcium carbonate), add them to the reaction vessel, and disperse them by ultrasonication (1 kW power) at 300 rpm for 30 minutes to obtain suspension A; A2. Preparation of reaction solution: Weigh 1.08 kg of zinc sulfate heptahydrate and 0.96 kg of sodium tetraborate decahydrate, respectively, and dissolve them in 10 kg of deionized water to obtain mixed aqueous solution B; A3. Coating reaction: Heat suspension A to 65°C and stir at 200 rpm. Slowly and evenly add mixed aqueous solution B to suspension A over 1 hour. After the addition is complete, continue the reaction at 65°C for 2.5 hours. During the reaction, add dilute ammonia to maintain the pH of the system at around 9.0. A4. Post-processing: After the reaction is complete, filter the mixture and wash the filter cake with deionized water until the conductivity of the filtrate is basically constant. Dry the obtained solid at 110℃ for 14 hours, pulverize it and pass it through a 400-mesh sieve to obtain zinc borate coated calcium carbonate. The preparation method of the composite layered silicate nanocomposite material includes: weighing organo-modified montmorillonite and nano-sepiolite at a weight ratio of 1:2.2, stirring and mixing them at 200 rpm for 30 minutes in a low-speed mixer at room temperature until they are homogeneous, and then obtaining the composite material. The production process of the fire-resistant high-strength plastic flooring material in this embodiment includes the following steps: S1. Raw material pretreatment: Surface-modified aluminum hydroxide, zinc borate-coated calcium carbonate, and composite layered silicate nanocomposites were prepared respectively; S2. Filler premixing: Surface-modified aluminum hydroxide, zinc borate-coated calcium carbonate, and compounded layered silicate nanocomposite materials are blended to obtain composite filler. The composite filler, aluminum hypophosphite, and nano silica are added to a high-speed mixer and stirred at 80°C and 600 rpm for 25 minutes to obtain premixed filler. S3. Main ingredient mixing: Polyvinyl chloride, ethylene-vinyl acetate copolymer, calcium-zinc composite stabilizer, antioxidant 1010 and ultraviolet absorber UV-326 are added to a high-speed mixer, heated to 105℃ and stirred at 800 rpm for 8 minutes; cooled to 85℃, acetylated tributyl citrate and maleic anhydride-grafted POE are added, and stirred at 600 rpm for 5 minutes; the premixed filler obtained in step S2 is added, and the speed is increased to 1000 rpm and stirred until the material temperature rises to about 115℃; oxidized polyethylene wax is added, and stirring is continued at 1000 rpm for 3 minutes; the mixed material is discharged into a cold mixer and cooled to below 40℃ to obtain the premix. S4. Melt Blending and Granulation: The premixed material is fed into a parallel co-rotating twin-screw extruder with a screw diameter of 52 mm, a length-to-diameter ratio of 40:1, and a screw speed of 300 rpm. The extrusion temperatures are set sequentially from the feed inlet to the die head as follows: feeding zone 140℃, melting zone 175℃, mixing zone 180℃, homogenization zone 180℃, and die head 175℃. After melt blending, the material is extruded, cooled in a water bath, dried by an air knife, and then granulated to obtain particles with a particle size of approximately 3 mm × 3 mm, which is the fire-resistant high-strength plastic flooring material.

[0022] Comparative Example 1 The method was adjusted based on Example 1. Unlike Example 1, surface-modified aluminum hydroxide was not added to the composite filler; its 15 parts were made up by an equal amount of zinc borate-coated calcium carbonate. The rest is the same as in Example 1.

[0023] Comparative Example 2 The method was adjusted based on Example 1. Unlike Example 1, no composite layered silicate nanocomposite material was added to the composite filler. Instead, its 5 parts were made up by equal amounts of 3 parts surface-modified aluminum hydroxide and 2 parts zinc borate-coated calcium carbonate. The rest was the same as in Example 1.

[0024] Comparative Example 3 The method was adjusted based on Example 1. Unlike Example 1, zinc borate-coated calcium carbonate was not added to the composite filler. Instead, its 5 parts were made up by equal amounts of 3 parts of surface-modified aluminum hydroxide and 2 parts of the composite layered silicate nanocomposite material. The rest is the same as in Example 1.

[0025] Comparative Example 4 This example is an adjustment based on Example 1, except that zinc borate-coated calcium carbonate is replaced with an equal amount of uncoated ordinary light calcium carbonate. Everything else is the same as in Example 1.

[0026] Comparative Example 5 This example is an adjustment based on Example 1, except that the surface-modified aluminum hydroxide is replaced with an equal amount of unmodified ordinary aluminum hydroxide powder. Everything else is the same as in Example 1.

[0027] Comparative Example 6 The following adjustments were made based on Example 1, except that the composite layered silicate nanocomposite material (organic montmorillonite: nano sepiolite = 1:2) was replaced with an equal amount of single organic montmorillonite. The rest remained the same as in Example 1.

[0028] Test Example: The fire-resistant high-strength plastic flooring materials prepared in Examples 1-3 and Comparative Examples 1-6 were subjected to the following tests: Tensile property test: Referring to GB / T 1040.2-2022 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics", the material was made into a type 1A standard dumbbell-shaped specimen. The specimen was stretched at 50 mm / min using a universal testing machine until it broke. The tensile strength (MPa) and elongation at break (%) were recorded. Thermo-oxidative aging test: According to GB / T 7141-2008 "Test Method for Thermal Aging of Plastics", the sample was placed in a forced-air oven at 100℃ and aged for 168 hours. After being taken out and cooled, its tensile strength was tested and the retention rate (%) was calculated. Hardness: The test was conducted in accordance with GB / T 2411-2008 "Determination of indentation hardness (Shore hardness) of plastics and hard rubber using a hardness tester"; Abrasion resistance: The material is made into a disc sample with a thickness of 2 mm and a diameter of about 100 mm. It is installed on the Taber abrasion tester, a load of 500 g is applied, and the sample is removed after 500 revolutions with a friction wheel. The mass loss (mg) of the sample before and after friction is measured. Limiting Oxygen Index (LOI): Tested according to standard GB / T 2406.2-2009 "Determination of Combustion Behavior by Oxygen Index Method for Plastics - Part 2: Room Temperature Test"; The results are shown in Table 1 below: Table 1

[0029] Based on the above, it can be seen that Examples 1-3, through careful design, utilize surface-modified aluminum hydroxide as a highly efficient flame retardant and filler, compounded layered silicate nanomaterials as nano-reinforcement and barrier, and zinc borate-coated calcium carbonate as a synergistic flame retardant and interface modifier. The combination of these three elements forms a multifunctional, multi-scale synergistic composite filler system. This system achieves a balance between high strength, high toughness, good wear resistance, and thermal stability while ensuring excellent flame retardancy.

[0030] In Comparative Example 1, the absence of surface-modified aluminum hydroxide resulted in a significant decrease in the material's overall mechanical properties, such as tensile strength, elongation at break, and LOI (Lack of Intensity). Surface-modified aluminum hydroxide not only provides efficient flame retardancy, but its excellent interfacial bonding with the matrix is ​​also crucial for enhancing the material's strength and toughness. Its absence leads to poor compatibility between the filler and resin, resulting in stress defects and decreased mechanical properties; simultaneously, the synergistic effect of the flame-retardant system is weakened, leading to a lower LOI. The slight increase in hardness may be due to the rigid particle filling effect of ordinary calcium carbonate and silica.

[0031] Comparative Example 2, lacking the composite layered silicate nanocomposite, showed a significant deterioration in the material's toughness, such as elongation at break and abrasion resistance, as well as poorer thermo-oxidative aging performance. The combination of layered silicate montmorillonite and fibrous silicate sepiolite greatly improved the material's tear resistance, abrasion resistance, and dimensional stability. Without this nano-reinforcing effect, the material became brittle, and its abrasion resistance decreased. The decrease in flame retardancy (LOI) was limited because the main gas-phase flame retardants (aluminum hypophosphite and aluminum hydroxide) remained.

[0032] In Comparative Example 3, the lack of zinc borate-coated calcium carbonate resulted in a comprehensive decline in the material's flame retardancy (LOI), thermal stability (thermal-oxidative aging retention rate), and abrasion resistance. Zinc borate-coated calcium carbonate acts as a multifunctional synergist: zinc borate provides condensed-phase flame retardancy and smoke suppression; the coating structure improves the compatibility between calcium carbonate and the matrix, reducing the loss of mechanical and abrasion resistance properties due to interfacial weakness. Without it, both the synergistic effect of the flame retardant system and the filler reinforcement effect are weakened.

[0033] In Comparative Example 4, replacing zinc borate-coated calcium carbonate with ordinary calcium carbonate significantly reduced the material's flame retardancy (LOI) and thermo-oxidative aging performance, and also worsened its abrasion resistance. Ordinary calcium carbonate is merely an inert filler with no flame retardant function and has limited compatibility with polymers, making it a weak point at the interface. In contrast, zinc borate-coated calcium carbonate combines flame retardancy with interface improvement. This comparison confirms the importance of the coating structure in imparting flame retardancy to fillers and improving the overall performance of composite materials.

[0034] In Comparative Example 5, replacing surface-modified aluminum hydroxide with unmodified aluminum hydroxide resulted in a significant decrease in the mechanical properties of the material, particularly its elongation at break and thermo-oxidative aging performance. Unmodified aluminum hydroxide exhibits poor compatibility with non-polar polymer matrices such as polyvinyl chloride (PVC), easily agglomerating and leading to stress concentration, which becomes a weak point in the material and severely impairs its toughness and strength. Simultaneously, poor compatibility also affects its thermal stability and dispersion uniformity. This comparison highlights the crucial role of surface modification in improving the compatibility of inorganic fillers with organic matrices, thereby maximizing their functionality.

[0035] Comparative Example 6, which used a single organic montmorillonite instead of the composite nanocomposite material, showed inferior toughness, abrasion resistance, and flame retardancy (LOI) compared to Example 1. The single lamellar montmorillonite primarily provides a gas barrier effect and some reinforcement, but lacks the bridging and network reinforcement effects of fibrous sepiolite. The combination of the two produced a synergistic reinforcement effect, superior to the single component in improving mechanical properties, abrasion resistance, and flame retardancy and smoke suppression.

[0036] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fire-resistant, high-strength plastic flooring material, characterized in that, The product comprises, by weight, the following components: 45-65 parts of matrix resin, 20-30 parts of composite filler, 10-12 parts of tributyl acetylacetonate, 6-8 parts of calcium-zinc composite stabilizer, 6-9 parts of aluminum hypophosphite, 3-5 parts of nano-silica, 2-3 parts of maleic anhydride-grafted POE, 1-2 parts of oxidized polyethylene wax, 0.5-1 part of antioxidant, and 0.5-1 part of ultraviolet absorber; wherein the composite filler is composed of surface-modified aluminum hydroxide, compounded layered silicate nanocomposite material, and zinc borate-coated calcium carbonate; and the matrix resin is composed of a copolymer of polyvinyl chloride and ethylene-vinyl acetate in a weight ratio of 3.5-5:

1.

2. The fire-resistant high-strength plastic flooring material according to claim 1, characterized in that, The preparation method of the surface-modified aluminum hydroxide includes: preheating aluminum hydroxide powder to 70-85°C, spraying a solution of silane coupling agent KH-570 diluted with anhydrous ethanol into the powder in atomized form under high-speed stirring, controlling the reaction temperature at 85-90°C and stirring continuously for 15-25 minutes, and then cooling and discharging the powder to obtain the surface-modified aluminum hydroxide.

3. The fire-resistant high-strength plastic flooring material according to claim 2, characterized in that, The amount of the silane coupling agent KH-570 added is 1.0%-1.5% of the weight of the aluminum hydroxide powder.

4. The fire-resistant high-strength plastic flooring material according to claim 1, characterized in that, The composite layered silicate nanocomposite material comprises organo-modified montmorillonite and nano-sepiolite in a weight ratio of 1:1.8-2.

2.

5. The fire-resistant high-strength plastic flooring material according to claim 1, characterized in that, The method for preparing zinc borate-coated calcium carbonate includes: A1. Dispersion: Calcium carbonate, deionized water and sodium polyacrylate dispersant are mixed and ultrasonically dispersed to obtain suspension A; A2. Preparation of reaction solution: Prepare a mixed aqueous solution containing zinc source and boron source B; A3. Coating reaction: Under conditions of 55-65℃ and continuous stirring, the mixed aqueous solution B is added dropwise to the suspension A. After the addition is complete, the reaction is kept at the temperature for 1.5-2.5 hours, and the pH of the system is adjusted to 8.0-9.

0. A4. Post-processing: After the reaction is completed, solid-liquid separation is performed. The obtained solid is washed, dried at 100-110℃ for 10-14 hours, and then sieved to obtain the zinc borate-coated calcium carbonate.

6. The fire-resistant high-strength plastic flooring material according to claim 5, characterized in that, The weight ratio of calcium carbonate, deionized water and sodium polyacrylate is 20:180-220:0.1-0.

3.

7. The fire-resistant high-strength plastic flooring material according to claim 5, characterized in that, The weight ratio of the calcium carbonate, the zinc source, and the boron source is 100:13-18:11-16.

8. The fire-resistant high-strength plastic flooring material according to claim 1, characterized in that, The antioxidant is antioxidant 1010; the ultraviolet absorber is ultraviolet absorber UV-326.

9. A manufacturing process for a fire-resistant high-strength plastic flooring material according to any one of claims 1-8, characterized in that the steps include... include: S1. Raw material pretreatment: Surface-modified aluminum hydroxide, composite layered silicate nanocomposite material and zinc borate-coated calcium carbonate were prepared respectively; S2. Filler premixing: The surface-modified aluminum hydroxide, the compounded layered silicate nanocomposite material, and the zinc borate-coated calcium carbonate are blended to obtain a composite filler. The composite filler, aluminum hypophosphite, and nano silica are premixed in a high-speed mixer at 60-80°C for 10-25 minutes to obtain a premixed filler. S3. Main ingredient mixing: Add polyvinyl chloride, ethylene-vinyl acetate copolymer, calcium-zinc composite stabilizer, antioxidant and ultraviolet absorber to a high-speed mixer, heat to 95-105℃ and stir for 5-8 minutes; cool to 75-85℃, add acetylated tributyl citrate and maleic anhydride-grafted POE, stir for 3-5 minutes; add the premixed filler obtained in step S2, stir at high speed until the material temperature reaches 110-115℃; add oxidized polyethylene wax, stir for 2-3 minutes and then cool to below 45℃ to obtain the premix; S4. Melt blending and granulation: The premixed material is fed into a parallel co-rotating twin-screw extruder, and after melt blending, extrusion, cooling and pelletizing, the fire-resistant high-strength plastic flooring material is obtained.

10. The production process of a fire-resistant high-strength plastic flooring material according to claim 9, characterized in that, In step S4, the process parameters of the parallel co-rotating twin-screw extruder are as follows: screw speed 200-300 rpm; extrusion temperature settings from the feed inlet to the die head are: feeding zone 130-140℃, melting zone 155-175℃, mixing zone 170-180℃, homogenizing zone 175-180℃, and die head 170-175℃.

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