Multi-layer foamed floor and preparation method thereof

Abstract

The invention discloses a multi-layer foaming floor and a preparation method thereof, and relates to the technical field of composite floors. The multi-layer foaming floor comprises a surface layer and a core layer, a surface layer-core layer-surface layer structural form is adopted. Wherein the surface layer is prepared from the following raw materials in parts by mass: 40-60 parts of PVC resin powder, 80-110 parts of calcium carbonate, 35-60 parts of a common recycled material, 2-4 parts of a calcium-zinc stabilizer, 2-4 parts of a foaming processing aid, 2-4 parts of a flexibilizer, 0.5-3 parts of an internal lubricant, 0.5-3 parts of an external lubricant and 0.1-0.5 part of carbon black; the core layer is prepared from the following raw materials in parts by mass: 40 to 60 parts of PVC resin powder, 80 to 100 parts of calcium carbonate, 40 to 60 parts of foaming recycled material, 3 to 5 parts of calcium-zinc stabilizer, 1 to 3 parts of foaming processing aid, 5 to 10 parts of foaming regulator, 0.1 to 0.5 part of yellow foaming agent, 0.1 to 0.3 part of white foaming agent, 0.5 to 3 parts of internal lubricant and 0.5 to 3 parts of external lubricant. The multilayer foamed floor prepared by the invention can effectively control the warping problem of the back surface of a product, improves the thermal stability of the floor, and shows more excellent comprehensive performance.

Description

Technical Field

[0001] The present invention relates to the technical field of composite flooring, and in particular to a multi-layer foamed flooring and a preparation method thereof. Background Art

[0002] In recent years, the PVC flooring market has shown a rapid growth trend. The global scale continues to expand, Europe and the United States have become the main consumer markets, and China is a major producer and exporter, with exports rising year by year.

[0003] In terms of competition, international brands occupy the high end, domestic brands are numerous and the concentration is low, and some companies have emerged through quality and research and development. Products are developing in the direction of environmental protection, multi-function and beauty. However, there are problems of inferior products in the market, and it is affected by fluctuations in raw material prices. Overall, the prospects are broad but challenges coexist.

[0004] Today's flooring market has new requirements for products. Flooring with good toughness, good stability and lighter weight has become the focus of the market. Good toughness can withstand impact and pressure, and good stability can adapt to a variety of environments and avoid deformation. Lighter floors are more convenient for both transportation and installation. Floors that meet these characteristics are urgently needed by the market and will also lead the development direction of the flooring industry.

[0005] However, traditional PVC flooring still has shortcomings in meeting the above characteristics. For example, it is difficult to balance toughness and stability, especially in high temperature environments, it is prone to warping and shrinkage. At the same time, compared with conventional SPC floors, how to maintain or even improve mechanical properties such as static bending strength and elastic modulus while reducing weight is still a problem that needs to be solved urgently in existing technologies. Summary of the invention

[0006] In order to solve the deficiencies of existing floors in terms of weight, toughness and high temperature stability, the present invention aims to provide a multi-layer foamed PCV floor formula and its preparation and production process.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0008] The first aspect of the present invention provides a multi-layer foam floor, comprising a surface layer and a core layer; the surface layer is composed of the following raw materials in parts by weight: 40-60 parts of PVC resin powder, 80-110 parts of calcium carbonate, 35-60 parts of ordinary recycled materials, 2-4 parts of calcium zinc stabilizer, 2-4 parts of foaming processing aid, 2-4 parts of toughening agent, 0.5-3 parts of internal lubricant, 0.5-3 parts of external lubricant, and 0.1-0.5 parts of carbon black.

[0009] Preferably, the surface layer is composed of the following raw materials in parts by mass: 50 parts of PVC resin powder, 100 parts of calcium carbonate, 40 parts of ordinary recycled materials, 3.6 parts of calcium zinc stabilizer, 3 parts of foaming processing aid, 2.2 parts of toughening agent, 1 part of internal lubricant, 0.8 parts of external lubricant, and 0.3 parts of carbon black.

[0010] Furthermore, the PVC resin powder is conventional SG5 powder.

[0011] Furthermore, the calcium carbonate is 400 mesh calcium carbonate.

[0012] Furthermore, the foaming processing aid is ACR.

[0013] Furthermore, the toughening agent is modified CPVC resin particles.

[0014] In some embodiments, the modified CPVC resin particles are composed of the following raw materials in parts by mass: 100 parts of CPVC with a chlorine content of 67%, 4 parts of CPE with a chlorine content of 35%, 10 parts of SG-5 model PVC powder, 10 parts of MBS resin, 5 parts of calcium zinc stabilizer, and 0.4 parts of PE wax.

[0015] In some embodiments, the core layer of the multi-layer foam floor is composed of the following raw materials in parts by weight: 40-60 parts of PVC resin powder, 80-100 parts of calcium carbonate, 40-60 parts of foamed recycled materials, 3-5 parts of calcium zinc stabilizer, 1-3 parts of foaming processing aid, 5-10 parts of foaming regulator, 0.1-0.5 parts of yellow foaming agent, 0.1-0.3 parts of white foaming agent, 0.5-3 parts of internal lubricant, and 0.5-3 parts of external lubricant.

[0016] Preferably, the core layer is composed of the following raw materials in parts by mass: 50 parts of PVC resin powder, 85 parts of calcium carbonate, 40 parts of foaming recycled materials, 4 parts of calcium zinc stabilizer, 2.5 parts of foaming processing aid, 6 parts of foaming regulator, 0.25 parts of yellow foaming agent, 0.1 parts of white foaming agent, 0.95 parts of internal lubricant, and 0.8 parts of external lubricant.

[0017] Furthermore, the PVC powder is conventional SG8 powder.

[0018] Furthermore, the calcium carbonate is 1250 mesh calcium carbonate.

[0019] Furthermore, the foaming processing aid is ACR.

[0020] Furthermore, the foaming regulator is a high molecular weight acrylic ester PVC processing aid with a molecular weight in the range of 5-6.5 million.

[0021] In some embodiments, the multi-layer foam floor consists of a structure of surface layer-core layer-surface layer.

[0022] A second aspect of the present invention provides a method for preparing a multi-layer foam floor, comprising the following steps:

[0023] S1. Stir and heat the surface layer and core layer materials to 110-120°C respectively;

[0024] S2. After cooling, it is transported to the extruder;

[0025] S3. The core material is injected into the mold through the confluence core, the surface material is injected into the mold through the confluence core and the flow channel, and the surface layer - core layer - surface layer structure is achieved through the distributor;

[0026] S4. The board is extruded through a mold, and the finished product is obtained by cooling, shaping, laminating, trimming and cutting.

[0027] The beneficial effects of the present invention include at least:

[0028] 1) By using toughening agents, the static bending strength, elastic modulus, displacement and other indicators of the plate can be effectively improved, and the toughness of the material can be enhanced;

[0029] 2) By adopting the structure of surface layer-core layer-surface layer, the warping problem on the back of the product can be effectively controlled and the stability of the floor can be improved. When kept at a high temperature of 80°C for 6 hours, the shrinkage and warping stability of the foamed floor of the present invention are better than those of the current cold-paste series multi-layer floor.

[0030] 3) By adopting the core layer foaming technology, the weight of the foamed floor of the present invention is reduced by at least 20% compared with the conventional SPC floor, which makes the foamed floor more convenient in transportation and installation while retaining higher mechanical properties. DETAILED DESCRIPTION

[0031] The experimental methods in the following examples of the present invention, where no specific conditions are specified, are usually carried out under conventional conditions or under conditions recommended by the manufacturers. The various commonly used chemical reagents used in the examples are all commercially available products.

[0032] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0033] The terms "including" and "having" and any variations thereof of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, device, product or equipment comprising a series of steps is not limited to the listed steps or modules, but may optionally include steps not listed, or may optionally include other steps inherent to these processes, methods, products or equipment.

[0034] 1. Surface layer extrusion formula and preparation method:

[0035] The surface layer extrusion formula of the present invention is composed of the following components in parts by weight: 40-60 parts of PVC resin powder, 80-100 parts of 400-mesh heavy calcium carbonate, 40-60 parts of common recycled materials, 2-4 parts of calcium zinc stabilizer, 2-4 parts of ACR processing aid, 2-4 parts of toughening agent, 0.5-3 parts of internal lubricant, 0.5-3 parts of external lubricant and 0.1-0.5 parts of carbon black.

[0036] Among them, the PVC powder used is conventional SG5 powder;

[0037] The selected calcium carbonate powder particle size is 400 mesh. Too coarse particles will cause the product to burn easily, while too fine particles will increase the cost and easily cause the product to be too brittle.

[0038] Among them, the common recycled materials used are crushed materials of PVC floor;

[0039] Among them, the selected calcium zinc stabilizer is a non-toxic and environmentally friendly calcium zinc stabilizer for PVC, which is composed of zinc soap, calcium soap, auxiliary stabilizer, lubricant, etc.; it has the characteristics of non-toxicity, high efficiency, good stability, fine foam cells of products, good demoulding performance, excellent processing performance, and long production cycle;

[0040] Among them, the foaming processing aid selected is ACR, which is copolymerized by MMA and acrylic esters. It can promote the plasticization performance of PVCU during processing and improve its fluidity.

[0041] Among them, the internal lubricant selected is G60, which is a lubricant whose main components include stearic acid, etc. It is a dicarboxylic acid ester containing fatty alcohol;

[0042] Among them, the external lubricant selected is PE wax;

[0043] Among them, the toughening agent selected is modified CPVC resin particles, and its preparation formula and process are as follows:

[0044] (1) Weigh 100 parts by weight of CPVC with a chlorine content of 67%; weigh 4 parts by weight of CPE with a chlorine content of 35%, which is mainly used as a compatibilizer to increase the bonding force between CPVC and PVC and enhance the mechanical properties; weigh 10 parts by weight of SG-5 model PVC powder; weigh 10 parts by weight of MBS resin (a terpolymer of methyl methacrylate (M), butadiene (B) and styrene (S)). Since its solubility parameter is similar to that of PVC, the two have good thermodynamic compatibility, which is manifested in that PVC has high impact strength at room temperature or low temperature; weigh 5 parts by weight of calcium zinc stabilizer; and 0.4 parts by weight of PE wax;

[0045] (2) After the materials in step (1) are weighed, they are placed in a mixer in the order of weighing and stirred, wherein the materials are first mixed in a low-speed mixer and then switched to a high-speed mixer, and the materials are added after the temperature reaches 90° C.;

[0046] (3) After the above operation in step (2), the unloading part is transferred to a conical twin-screw extruder for extrusion, and the temperature is set to 180-200°C;

[0047] (4) After step (3) of extrusion molding, the temperature is lowered for a period of time by cooling the die head, and then the die is pulled and cooled until it is completely molded and ready for the next step;

[0048] (5) continuing step (4) to carry out pelletizing and screening;

[0049] Among them, the carbon black used plays the role of coloring the board;

[0050] 2. Core layer extrusion formula and preparation method:

[0051] Core layer extrusion formula design: 40-60 parts of PVC resin powder, 80-100 parts of 1250 mesh calcium carbonate, 40-60 parts of foaming recycled material, 3-5 parts of calcium zinc stabilizer, 1-3 parts of ACR processing aid, 5-10 parts of foaming regulator, 0.1-0.5 parts of yellow foaming agent, 0.1-0.3 parts of white foaming agent, 0.5-3 parts of internal lubricant, and 0.5-3 parts of external lubricant.

[0052] Among them, the selected PVC powder is conventional SG8 powder, because the core layer is used for foaming, and the polymerization degree of SG-8 PVC resin powder is 740-650, and the K value is 59-55, which is more suitable for foaming;

[0053] Among them, the selected calcium carbonate powder is 1250 mesh. When the particle size of calcium carbonate matches the foaming agent, it can act as a nucleating agent, thereby promoting foaming. The appropriate calcium carbonate particle size is less than 5μm and does not agglomerate, so that it can better absorb the foaming gas to form bubble nuclei, control the number of pores, and make the pores finer. First of all, calcium carbonate can act as a nucleating agent to absorb foaming gas to form bubble nuclei, control the number of pores, and make the pores finer; improve melt properties: calcium carbonate itself has greater rigidity, which can slow down the deformation and mobility of the melt, thereby inhibiting the rapid expansion of the pores and controlling the pore size to be finer. When the particle size is less than 5μm: when the calcium carbonate particle size is less than 5μm, it can act as a nucleating agent to promote foaming. However, when the particle size is greater than 10μm: if the calcium carbonate particle size is greater than 10μm, or is too fine to cause self-agglomeration, it will affect the foaming effect;

[0054] Among them, the selected foaming recycled material is the crushed material of the foaming board;

[0055] Among them, the selected calcium zinc stabilizer is a non-toxic and environmentally friendly calcium zinc stabilizer for PVC, which is composed of zinc soap, calcium soap, auxiliary stabilizer, lubricant, etc.; it has the characteristics of non-toxicity, high efficiency, good stability, fine foam cells of products, good demoulding performance, excellent processing performance, and long production cycle;

[0056] Among them, the foaming processing aid selected is ACR, which is copolymerized by MMA and acrylic esters, and can promote the plasticization performance of PVCU during processing and improve its fluidity;

[0057] Among them, the internal lubricant selected is G60, which is a lubricant whose main components include stearic acid, etc. It is a dicarboxylic acid ester containing fatty alcohol;

[0058] Among them, the external lubricant selected is PE wax;

[0059] Among them, the foaming regulator used is actually an acrylic processing aid. It has all the basic characteristics of PVC processing aids. The only difference from the general PVC processing aid is the molecular weight. The foaming regulator belongs to the high molecular weight acrylic PVC processing aid, and its molecular weight is much higher than the molecular weight of PVC resin (generally between 50,000 and 110,000). The molecular weight of the foaming regulator is relatively high, usually between 5 million and 6.5 million, which can better entangle the PVC molecules together to form a gel network, thereby improving the melt strength, preventing bubbles and gas overflow, and ensuring the quality and density of the foamed products;

[0060] Among them, the selected yellow foaming agent has a gas emission of 220-230 ml / g, a decomposition temperature of 195-205°C, and a volatility of ≤0.2% (110°C 1H);

[0061] The selected white foaming agent has a gas emission of 130-140 ml / g, a decomposition temperature of 157-165° C., and a volatilization amount of ≤0.5% (110° C. 1H);

[0062] 3. A multi-layer co-extruded PVC floor substrate extrusion process, the specific steps are as follows:

[0063] S1. Add the materials of the surface layer and core layer, calcium carbonate and PVC powder into a high-speed mixer, and then add plasticizers, stabilizers, lubricants and other additives. Mix and stir and heat to 110-120℃, then cool. (The surface layer and core layer are placed in different kettles)

[0064] S2. When the S2 mixture is cooled to 65°C, it is placed in a storage bin, and the mixture in the storage bin is transported to the screw extruder through a spiral feeding system.

[0065] S3. Prepare the surface layer structure substrate (the material formula is designed as the surface layer extrusion formula above) by a twin-screw extruder, and prepare the core layer structure substrate (the material formula is designed as the core layer extrusion formula above) by another twin-screw extruder.

[0066] The core layer material is injected into the mold through the confluence core, and the surface layer material is injected into the mold through the confluence core and the flow channel. The mold distributor distributes the surface layer and the core layer according to the different injection flow channels of the core layer and the surface layer, so that the surface layer and the core layer materials are compounded in the mold to form a multi-layer structure.

[0067] S4, the extrusion section includes the following steps: equipment preparation before starting, starting the machine, discharging the material and pulling the plate, and shutting down the machine.

[0068] The specific implementation method of step S4 includes the following:

[0069] S4.1. Equipment preparation before startup mainly includes the following steps: equipment inspection and equipment heating / precooling.

[0070] The equipment inspection includes but is not limited to checking and ensuring that the power supply system and cooling water system function normally; checking and ensuring that the mold, distributor and vacuum device are installed normally;

[0071] The device heating / precooling comprises the following steps:

[0072] S4.1-1. Set the die opening temperature (170-180°C), the mold temperature (180-190°C), and the side plate temperature (190-210°C). Open the mold, die opening, and side plate and heat for about 2 hours.

[0073] S4.1-2. Set the extruder temperature according to the table below. It is allowed and should be adjusted appropriately while ensuring stable extrusion of the product. Turn on the heating for about 2.5 hours (Note: host numbers 7 and 8 are the confluence core temperatures).

[0074]

[0075] S4.1-3. Set the dispenser temperature according to the table below. It is allowed and should be adjusted appropriately while ensuring stable extrusion of the product. Turn on the heating for about 0.5 hours.

[0076] Runner 1 Runner 2 Runner 3 superior Down Distributor temperature 170～180 170～180 170～180 170～180 170～180

[0077] S4.1-4. Set the temperature of the mold rollers (1st roller 190℃, 2nd roller 190℃, 3rd roller 180℃, 4th and 5th rollers are cold water rollers). It is allowed and should be adjusted appropriately while ensuring stable extrusion of the product. Turn on the heating for about 1.5 hours.

[0078] S4.1-5. Set the shaping cooling roller and make sure the cooling water is flowing and the temperature is around 15℃.

[0079] S4.2, start up, mainly including the following steps:

[0080] Start the screw machine first, then set the 80# auxiliary machine speed to 200R / min and the feeding speed to 120R / min; after the 80# auxiliary machine discharges, set the 92# main machine speed to 200R / min and the feeding speed to 90R / min. Increase the speed slowly and several times, each increase by 20-40R / min. The stable speed, feeding speed and current are set according to the table below, and it is allowed and should be adjusted appropriately while ensuring stable extrusion of the product. (Note: When increasing the speed, observe the current and increase it slowly to avoid high current alarm.)

[0081] Speed ​​(reference) Feeding speed (reference) Steady current (reference) 80# Auxiliary machine 300R / min 300～310 90～100A 92# Host 400R / min 180～190 100～120A

[0082] Among them, taking the 6.5mm product as an example, set the speed of each roller as a reference:

[0083]

[0084] Among them, the reference for setting traction, bracket and lampshade is:

[0085] Traction Bracket 1 Bracket 2 Lampshade 1 Lampshade 2 Speed / Temperature 310～330 250～300 250～300 100℃ 100℃

[0086] S4.3, sheet extrusion and processing, mainly includes the following steps:

[0087] When extruding the sheet, move the machine and bring the die roller close to the extrusion die to prepare for pulling the sheet. After the extruded sheet comes out of the die, it is manually pulled to the cooling and shaping roller for transmission. After the flatness of the extruded sheet and the thickness of each layer are adjusted and confirmed, turn on the lampshade and start laminating. And according to the required width value of the laminated sheet, adjust the distance between the rotary blades to perform trimming. After the laminated sheet passes through the cooling zone, it is cut into the required size sheet by the shearing machine.

[0088] S4.4. Shutdown and cleanup

[0089] Turn off the heating system, the conveyor belt, the cooling system; turn off the silo, the screw machine and the die roller system. At the same time, clean the dust accumulated on the upper end of the main machine feed silo. Decide whether to replace it based on the actual situation of the residual material in the screw machine.

[0090] 4. Setting Example:

[0091] The specific formulas of Example 1, Example 2, and Example 3 are shown in Table 1; the preparation process of the examples is carried out according to the specific steps of the above-mentioned "III. A multi-layer co-extruded PVC floor substrate extrusion process".

[0092] Table 1 Flooring formula of each embodiment

[0093]

[0094]

[0095] Comparative Example 1

[0096] This comparative example prepared a conventional floor, and its formula and production process are as follows:

[0097] 1. Formula: The base material is 75 parts of PVC resin powder, 250 parts of heavy calcium carbonate, 7 parts of stabilizer, 0.7 parts of external lubricating PE wax, and 1.7 parts of internal lubricating CA80.

[0098] Among them, the PVC powder used is conventional SG5 powder;

[0099] The selected calcium carbonate powder needs to be 400 mesh. Too coarse particles will cause the product to burn easily, while too fine particles will increase the cost and easily cause the product to be too brittle.

[0100] Among them, the stabilizer selected is a non-toxic and environmentally friendly calcium zinc stabilizer;

[0101] Among them, the internal lubricant selected is stearic acid;

[0102] Among them, the external lubricant selected is PE wax;

[0103] 2. The substrate extrusion process, its characteristics and backing film selection include the following steps:

[0104] 2.1 Add 400 mesh heavy calcium carbonate, PVC powder and part of the recycled material into a high-speed mixer, then add plasticizer, stabilizer and lubricant, mix and stir, heat to 110-120℃ and then cool.

[0105] 2.2 When the mixed material prepared in 2.1 is cooled to 65°C, it is placed in a storage bin and the mixed material in the storage bin is transported to a twin-screw extruder (a conical twin-screw extruder) through a spiral feeding system.

[0106] 2.3 The barrel temperature is controlled at 160-180℃, the mold temperature is controlled at 200-220℃, the die cooling temperature is controlled at 100-140℃, and after extrusion, it is formed by the mold, and the thickness is adjusted and shaped by rollers 1 and 2. Roller 3 is used to laminate the color film and the wear-resistant layer, and rollers 4 and 5 are used for embossing. After cooling, it is cut to obtain the sheet.

[0107] Comparative Example 2

[0108] This comparative example prepared a conventional cold-pasted multi-layer floor, and its formula and production process are as follows:

[0109] 1. Conventional cold-pasted multi-layer floor: The base material components are 400 parts of PVC resin powder, 1700 parts of calcium carbonate, 150 parts of DOTP oil, 7 parts of stabilizer and 3 parts of carbon black.

[0110] Among them, the PVC powder used is conventional SG5 powder;

[0111] Among them, the selected calcium carbonate powder needs to be 400 mesh;

[0112] Among them, the stabilizer selected is calcium zinc stabilizer;

[0113] 2. The substrate extrusion process, its characteristics and backing film selection include the following steps:

[0114] 2.1 Add 400 mesh heavy calcium carbonate and PVC powder into the internal mixer, and then add stabilizer, carbon black and DOTP oil for internal mixing;

[0115] 2.2 The mixed material in 2.1 is milled and formed into an LVT substrate layer by calendering.

[0116] 2.3 Use a hot press to heat-press the wear-resistant layer, color film and LVT substrate layer.

[0117] 2.4 Use glue to bond the semi-finished products to the purchased wood-plastic substrate.

[0118] 2.5 The semi-finished product in 2.4 is glued to the LVT substrate layer again to obtain a cold-laminated multi-layer floor.

[0119] Test Example 1: Physical properties of the floors prepared in the embodiment and the control example were tested, and the results are shown in Table 2.

[0120] Table 2. Physical property test comparison

[0121]

[0122]

[0123] As shown in Table 2, the multi-layer foam floor of the present application (Examples 1-3) is significantly better than the cold-pasted multi-layer floor (Control Example 2) in terms of static bending strength, elastic modulus and residual sag, indicating that the formula design of the surface layer and the core layer and the "surface layer-core layer-surface layer" structure have significant advantages, produce better synergistic effects, and show better comprehensive performance.

[0124] Test Example 2: The floors prepared in the embodiment and the control example were compared in terms of warping during installation. The results are shown in Table 3.

[0125] Table 3. Pavement warpage comparison (unit: mm)

[0126] time Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Day 1 0.00 0.05 0.05 0.00 0.05 the next day 0.00 0.10 0.15 0.15 0.22 Day 3 0.05 0.15 0.30 0.25 0.94 Day 4 0.05 0.15 0.45 0.30 1.12 Day 5 0.11 0.25 0.50 0.31 1.20 Day 6 0.12 0.31 0.55 0.33 1.36 Day 7 0.16 0.41 0.60 0.35 1.42

[0127] Note: The warping comparison of the floor is to place the floor in a constant temperature room, and go through 35℃*12H and 0℃*12H, which is one cycle and the time is one day.

[0128] As shown in Table 3, the warping values ​​of Examples 1-3 were significantly lower than those of the conventional cold-applied multi-layer floor (Control Group 2) throughout the entire experimental period, indicating that the multi-layer foaming structure can effectively improve the anti-warping performance.

[0129] Among them, the warpage value of Example 1 was only 0.16mm on the seventh day, which was lower than that of the other two examples. This is because the surface layer and core layer formula in Example 1 are better, and the surface layer and core layer formula and the "surface layer-core layer-surface layer" structural design produce unexpected synergistic effects. It can effectively reduce the stress accumulation inside the floor, making it more stable in a temperature difference environment. In addition, the foamed core layer provides a good buffering effect, reducing the impact of thermal expansion of the floor.

[0130] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A multi-layer foam floor, characterized in that: It comprises a surface layer and a core layer; the surface layer is composed of the following raw materials in parts by mass: 40-60 parts of PVC resin powder, 80-110 parts of calcium carbonate, 35-60 parts of ordinary recycled materials, 2-4 parts of calcium zinc stabilizer, 2-4 parts of foaming processing aid, 2-4 parts of toughening agent, 0.5-3 parts of internal lubricant, 0.5-3 parts of external lubricant, and 0.1-0.5 parts of carbon black.

2. The multi-layer foam floor according to claim 1, characterized in that: The surface layer is composed of the following raw materials in parts by mass: 50 parts of PVC resin powder, 100 parts of calcium carbonate, 40 parts of common recycled materials, 3.6 parts of calcium zinc stabilizer, 3 parts of foaming processing aid, 2.2 parts of toughening agent, 1 part of internal lubricant, 0.8 parts of external lubricant, and 0.3 parts of carbon black.

3. The multi-layer foam floor according to claim 1-2, characterized in that: The PVC resin powder is conventional SG5 powder; and / or; The calcium carbonate is 400 mesh calcium carbonate; and / or; The foaming processing aid is ACR; and / or; The toughening agent is modified CPVC resin particles.

4. The multi-layer foam floor according to claim 3, characterized in that: The modified CPVC resin particles are composed of the following raw materials in parts by mass: 100 parts of CPVC with a chlorine content of 67%, 4 parts of CPE with a chlorine content of 35%, 10 parts of SG-5 model PVC powder, 10 parts of MBS resin, 5 parts of calcium zinc stabilizer, and 0.4 parts of PE wax.

5. The multi-layer foam floor according to claim 1, characterized in that: The core layer is composed of the following raw materials in parts by weight: 40-60 parts of PVC resin powder, 80-100 parts of calcium carbonate, 40-60 parts of foaming recycled materials, 3-5 parts of calcium zinc stabilizer, 1-3 parts of foaming processing aid, 5-10 parts of foaming regulator, 0.1-0.5 parts of yellow foaming agent, 0.1-0.3 parts of white foaming agent, 0.5-3 parts of internal lubricant, and 0.5-3 parts of external lubricant.

6. The multi-layer foam floor according to claim 5, characterized in that: The core layer is composed of the following raw materials in parts by weight: 50 parts of PVC resin powder, 85 parts of calcium carbonate, 40 parts of foaming recycled materials, 4 parts of calcium zinc stabilizer, 2.5 parts of foaming processing aid, 6 parts of foaming regulator, 0.25 parts of yellow foaming agent, 0.1 parts of white foaming agent, 0.95 parts of internal lubricant, and 0.8 parts of external lubricant.

7. The multi-layer foam floor according to claims 5-6, characterized in that: The PVC powder is conventional SG8 powder; and / or; The calcium carbonate is 1250 mesh calcium carbonate; and / or; The foaming processing aid is ACR; and / or; The foaming regulator is an acrylic ester PVC processing aid with a molecular weight in the range of 5-6.5 million.

8. The multi-layer foam floor according to claim 1, characterized in that: The multi-layer foamed floor consists of a structure of surface layer-core layer-surface layer.

9. A method for preparing a multi-layer foamed floor according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Stir and heat the surface layer and core layer materials to 110-120°C respectively; S2. After cooling, it is transported to the extruder; S3. The core material is injected into the mold through the confluence core, the surface material is injected into the mold through the confluence core and the flow channel, and the surface layer - core layer - surface layer structure is achieved through the distributor; S4. The board is extruded through a mold, and the finished product is obtained by cooling, shaping, laminating, trimming and cutting.

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