A kind of PVC sports flooring and preparation method thereof

Abstract

The invention discloses a PVC sports flooring and a preparation method thereof. The PVC sports flooring consists of a base fabric, a foaming layer, a surface layer and a PVC layer from bottom to top. The foaming layer is made of polyvinyl chloride paste resin, porous filler, nano zinc oxide, plasticizer, potassium zinc stabilizer and foaming agent. The porous filler is added to the foaming layer, so that bubbles generated when the foaming agent in the foaming layer foams generate uniform and fine bubbles due to the high specific surface area of ​​the porous filler, so that the foaming structure is more uniform and the bubble structure is denser. The bubbles in the formed foaming layer are uniform and dense, and have excellent shock absorption performance. At the same time, the dispersion of the porous filler in the PVC paste resin is good, so the wear resistance and mechanical properties of the PVC paste resin are improved, and the PVC sports flooring has higher mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of sports flooring, relates to PVC materials, and particularly relates to a PVC sports flooring and a preparation method thereof. Background Art

[0002] PVC sports flooring is a type of flooring made of polyvinyl chloride material specifically developed for sports venues. PVC sports flooring has certain shock-absorbing properties and has a certain rebound ability to protect athletes when impacted. This relies on the foaming layer in the PVC sports flooring. The foaming layer is made by a foaming agent generating gas to expand the PVC material. The interior is filled with bubbles, making the foaming layer like a cushion with air inside, providing a cushioning effect for athletes and reducing the risk of athletes falling during exercise.

[0003] Currently, the most commonly used foaming agent is azodicarbonamide, also known as AC foaming agent. It produces nitrogen, carbon monoxide, carbon dioxide, and ammonia when decomposed by heat. However, AC foaming agent also instantly releases a large amount of heat and gas when decomposing at high temperatures. The large amount of heat can further reduce the viscoelasticity of the PVC melt, while the rapidly released gas can easily cause uneven distribution of initial bubble nuclei and lead to the rupture of some bubble cells. This makes it impossible to control the structure and size of the bubble throughout the foaming process, ultimately resulting in a significant reduction in the shock absorption performance of the product.

[0004] Chinese patent publication number CN110628147A discloses a modified PVC foam mat and its preparation method. By adding ultrafine metal powder to the foam layer, the composite material's cell size is reduced and the uniformity of the cell distribution is improved. However, this is affected by the dispersibility of the ultrafine metal powder in the PVC foam layer, and the ultrafine metal powder may agglomerate with other fillers, resulting in uneven foaming of the foam layer. Summary of the Invention

[0005] The purpose of the present invention is to provide a PVC sports flooring and a preparation method thereof, so as to solve the problems of uneven foaming, easy rupture of foams during foaming, and low strength and toughness of the foamed layer.

[0006] The present invention increases the specific surface area of ​​the filler by adding a porous filler into the foaming layer, making the foam produced by the foaming agent more uniform and denser. By compounding nano zinc oxide in the porous filler, the reaction activation energy of the foaming agent is reduced, and the mechanical properties of the PVC sports flooring are improved by the high dispersibility of the porous filler.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] The utility model relates to a PVC sports flooring, which consists of a base fabric, a foaming layer, a surface layer and a PVC layer from bottom to top.

[0009] The foaming layer comprises the following components in parts by weight: 80-120 parts of polyvinyl chloride paste resin, 54-68 parts of porous filler, 60-70 parts of plasticizer, 1-2 parts of potassium zinc stabilizer, and 6-10 parts of foaming agent.

[0010] The porous filler is prepared by the following steps:

[0011] Zn(NO3)2·4H2O and terephthalic acid are dissolved in N,N-dimethylformamide at 70-75°C, stirred for 70-72 hours, then heated to 105-110°C to produce precipitation, then cooled to 30-35°C for crystallization for 18-24 hours. After crystallization, it is filtered and washed with N,N-dimethylformamide, toluene, and ethanol in sequence. The precipitate is vacuum dried at 45-55°C to obtain a porous carrier, the porous carrier is dispersed in methanol, nano zinc oxide is added, and then stirred at 55-65°C until the methanol is completely volatilized to obtain a porous filler.

[0012] Furthermore, the surface layer comprises the following components by weight: 80-120 parts of polyvinyl chloride paste resin, 60-70 parts of plasticizer, 1-2 parts of potassium zinc stabilizer, and 30-35 parts of nano calcium carbonate.

[0013] Furthermore, the PVC layer comprises the following components in parts by weight: 80-100 parts of polyvinyl chloride resin, 55-65 parts of plasticizer and 1-2 parts of potassium zinc stabilizer.

[0014] Furthermore, the plasticizer is dioctyl phthalate, and the foaming agent is azodicarbonamide.

[0015] Furthermore, the mass ratio of the porous carrier to the nano zinc oxide is 25-30:2-4.

[0016] Furthermore, the usage ratio of Zn(NO3)2·4H2O, terephthalic acid and N,N-dimethylformamide is 3-3.5 g:0.7-0.8 g:100-110 mL.

[0017] A method for preparing PVC sports flooring comprises the following steps:

[0018] Step 1: Apply the foaming layer slurry on the base fabric with a coating amount of 800-1200g / m 2 , cure at 140-150℃ for 55-75s, cool, then cure at 80-120g / m 2 Apply the surface slurry on the surface of the solidified foaming layer and solidify it at 140-150℃ for 25-35s to obtain pre-foamed floor glue.

[0019] Step 2: Send the pre-foamed floor glue into the foaming furnace for foaming, so that the foaming layer is foamed to 4-8mm to obtain the foamed floor glue.

[0020] Step 3: Mix polyvinyl chloride resin, plasticizer and potassium zinc stabilizer, melt at 180-185℃ and apply it on the surface of the foam floor with a coating machine. The coating amount is 40-60g / m 2 After cooling and shaping, it is cut and embossed to obtain PVC sports flooring.

[0021] Furthermore, the foaming layer slurry is prepared by the following steps:

[0022] The polyvinyl chloride paste resin and the foaming agent are stirred evenly to obtain the foaming resin. The porous filler is dispersed in the slurry barrel with ethanol. After dispersion, the plasticizer and the potassium zinc stabilizer are added. The mixture is heated in a water bath to 50-60°C and stirred until the ethanol is completely volatilized. Then, the foaming resin is added to the slurry barrel and dispersed at a speed of 1200-1600rpm for 1-2h to obtain the foaming layer slurry.

[0023] Furthermore, the surface layer slurry is prepared by the following steps:

[0024] The polyvinyl chloride paste resin, plasticizer, potassium zinc stabilizer and nano calcium carbonate are mixed and dispersed at a speed of 1600-1800 rpm for 20-40 minutes to obtain a surface layer slurry.

[0025] Furthermore, in step 2, the foaming furnace includes four zones, the temperature of the first zone is 190-200°C, the temperature of the second zone is 190-210°C, the temperature of the third zone is 200-220°C, and the temperature of the fourth zone is 160-200°C.

[0026] Beneficial effects of the present invention:

[0027] (1) The present invention adds a porous filler to the foaming layer, so that the bubbles generated when the foaming agent in the foaming layer foams produce uniform and fine bubbles through the high specific surface area of ​​the porous filler, making the foaming structure more uniform and the bubble structure denser. The bubbles in the foaming layer formed are uniform and dense, and have excellent shock absorption performance. At the same time, the porous filler has a high dispersibility in the PVC paste resin because it contains carboxyl groups. The porous filler improves the wear resistance and mechanical properties of the PVC paste resin, thereby improving the mechanical properties of the PVC sports flooring.

[0028] (2) The present invention dissolves nano zinc oxide in methanol and incorporates the nano zinc oxide into the porous structure of the porous carrier. The nano zinc oxide can provide more active sites for the foaming agent, significantly affect the decomposition rate of the foaming agent, reduce the reaction activation energy, reduce the foaming temperature, and increase the foaming rate, so that the bubbles have enough time to be evenly dispersed in the foaming layer, thereby improving the toughness of the foaming layer and improving the shock absorption performance of the sports flooring.

[0029] (2) In the preparation method of the present invention, by mixing the porous filler loaded with nano zinc oxide with the plasticizer, part of the plasticizer is filled in the porous filler, which reduces the migration of the plasticizer to the surface of the foaming layer, and the obtained foaming layer has good flexibility. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] Example 1: A PVC sports flooring, comprising, from bottom to top, a base fabric, a foaming layer, a surface layer and a PVC layer.

[0032] A method for preparing PVC sports flooring comprises the following steps:

[0033] Step 1: Apply the foaming layer slurry on the base fabric with a coating amount of 800g / m 2 , cured at 140℃ for 55s, cooled, and then cured at 80g / m 2 The surface slurry is applied on the surface of the solidified foaming layer with a sizing amount of sizing, and cured at 140°C for 25s to obtain the pre-foamed floor glue.

[0034] Step 2: Send the pre-foamed floor glue into the foaming furnace for foaming, so that the foaming layer is foamed to 4mm to obtain the foamed floor glue.

[0035] Step 3: Mix 80g of polyvinyl chloride resin, 55g of dioctyl phthalate and 1g of potassium zinc stabilizer, melt them at 180℃ and apply them on the surface of the foam floor with a coating machine. The coating amount is 40g / m 2 After cooling and shaping, it is cut and embossed to obtain PVC sports flooring.

[0036] The foaming furnace consists of four zones, the temperature of the first zone is 190°C, the temperature of the second zone is 190°C, the temperature of the third zone is 200°C, and the temperature of the fourth zone is 160°C.

[0037] The foaming layer slurry is prepared by the following steps:

[0038] 800g of polyvinyl chloride paste resin and 60g of azodicarbonamide were stirred uniformly to obtain a foaming resin. 540g of porous filler was dispersed in a slurry barrel with 1L of ethanol. After dispersion, 600g of dioctyl phthalate and 10g of potassium zinc stabilizer were added. The mixture was heated to 50°C in a water bath and stirred until the ethanol was completely evaporated. Then, the foaming resin was added to the slurry barrel and dispersed at a speed of 1200rpm for 1h to obtain a foaming layer slurry.

[0039] The surface slurry is prepared by the following steps:

[0040] 80 g of polyvinyl chloride paste resin, 60 g of dioctyl phthalate, 1 g of potassium zinc stabilizer and 30 g of nano calcium carbonate were mixed and dispersed at a speed of 1600 rpm for 20 minutes to obtain a surface layer slurry.

[0041] The degree of polymerization of the polyvinyl chloride paste resin is 1000.

[0042] The porous filler is prepared by the following steps:

[0043] 900g Zn(NO3)2·4H2O and 210g terephthalic acid were dissolved in 30L N,N-dimethylformamide at 70°C, stirred for 70 hours, then heated to 105°C to produce precipitation, then cooled to 35°C for crystallization for 18 hours. After crystallization, it was filtered and washed with N,N-dimethylformamide, toluene, and ethanol in sequence. The precipitate was vacuum dried at 45°C to obtain a porous carrier. 500g of the porous carrier was dispersed in 1L methanol, 40g of nano-zinc oxide was added, and then stirred at 55°C until the methanol was completely volatilized to obtain a porous filler.

[0044] Example 2

[0045] A PVC sports flooring comprises, from bottom to top, a base fabric, a foaming layer, a surface layer and a PVC layer.

[0046] A method for preparing PVC sports flooring comprises the following steps:

[0047] Step 1: Apply the foaming layer slurry on the base fabric with a coating amount of 1000g / m 2 , cured at 145℃ for 65s, cooled, and then cured at 100g / m 2 The surface slurry is applied on the surface of the solidified foaming layer with a sizing amount of sizing, and solidified at 145°C for 30s to obtain the pre-foamed floor glue.

[0048] Step 2: Send the pre-foamed floor glue into the foaming furnace for foaming, so that the foaming layer is foamed to 6mm to obtain the foamed floor glue.

[0049] Step 3: Mix 90g of polyvinyl chloride resin, 60g of dioctyl phthalate and 1.5g of potassium zinc stabilizer, melt them at 183℃ and apply them on the surface of the foam floor with a coating machine. The coating amount is 50g / m 2 After cooling and shaping, it is cut and embossed to obtain PVC sports flooring.

[0050] The foaming furnace consists of four zones, the temperature of the first zone is 195°C, the temperature of the second zone is 200°C, the temperature of the third zone is 210°C, and the temperature of the fourth zone is 180°C.

[0051] The foaming layer slurry is prepared by the following steps:

[0052] 1000g of polyvinyl chloride paste resin and 80g of azodicarbonamide were stirred uniformly to obtain a foaming resin. 600g of porous filler was dispersed in a slurry barrel with 1L of ethanol. After dispersion, 650g of dioctyl phthalate and 15g of potassium zinc stabilizer were added. The mixture was heated to 55°C in a water bath and stirred until the ethanol was completely evaporated. Then, the foaming resin was added to the slurry barrel and dispersed at a speed of 1400rpm for 1.5h to obtain a foaming layer slurry.

[0053] The surface slurry is prepared by the following steps:

[0054] 100 g of polyvinyl chloride paste resin, 65 g of dioctyl phthalate, 1.5 g of potassium zinc stabilizer and 33 g of nano calcium carbonate were mixed and dispersed at a speed of 1700 rpm for 30 minutes to obtain a surface layer slurry.

[0055] The degree of polymerization of the polyvinyl chloride paste resin is 1300.

[0056] The porous filler is prepared by the following steps:

[0057] 1000g Zn(NO3)2·4H2O and 225g terephthalic acid were dissolved in 31L N,N-dimethylformamide at 73°C, stirred for 71 hours, then heated to 108°C to produce precipitation, then cooled to 33°C for crystallization for 21 hours. After crystallization, it was filtered and washed with N,N-dimethylformamide, toluene, and ethanol in sequence. The precipitate was washed and dried in vacuo at 50°C to obtain a porous carrier. 550g of the porous carrier was dispersed in 1L methanol, 60g of nano-zinc oxide was added, and then stirred at 60°C until the methanol was completely volatilized to obtain a porous filler.

[0058] Example 3: A PVC sports flooring, comprising, from bottom to top, a base fabric, a foaming layer, a surface layer and a PVC layer.

[0059] A method for preparing PVC sports flooring comprises the following steps:

[0060] Step 1: Apply the foaming layer slurry on the base fabric with a coating amount of 1200g / m 2 , cured at 150℃ for 75s, cooled, and then cured at 120g / m 2 The surface slurry is applied on the surface of the solidified foaming layer with a sizing amount of sizing, and cured at 150°C for 35s to obtain pre-foamed floor glue.

[0061] Step 2: Send the pre-foamed floor glue into the foaming furnace for foaming, so that the foaming layer is foamed to 8mm to obtain the foamed floor glue.

[0062] Step 3: Mix 100g polyvinyl chloride resin, 65g dioctyl phthalate and 2g potassium zinc stabilizer, melt at 185℃ and apply it on the surface of the foam floor with a coating machine. The coating amount is 60g / m 2 After cooling and shaping, it is cut and embossed to obtain PVC sports flooring.

[0063] The foaming furnace consists of four zones, the temperature of the first zone is 200°C, the temperature of the second zone is 210°C, the temperature of the third zone is 220°C, and the temperature of the fourth zone is 200°C.

[0064] The foaming layer slurry is prepared by the following steps:

[0065] 1200g of polyvinyl chloride paste resin and 100g of azodicarbonamide were stirred uniformly to obtain a foaming resin. 680g of porous filler was dispersed in a slurry barrel with 1L of ethanol. After dispersion, 700g of dioctyl phthalate and 20g of potassium zinc stabilizer were added. The mixture was heated to 60°C in a water bath and stirred until the ethanol was completely evaporated. Then, the foaming resin was added to the slurry barrel and dispersed at a speed of 1600rpm for 2h to obtain a foaming layer slurry.

[0066] The surface slurry is prepared by the following steps:

[0067] 120 g of polyvinyl chloride paste resin, 70 g of dioctyl phthalate, 2 g of potassium zinc stabilizer and 35 g of nano calcium carbonate were mixed and dispersed at a speed of 1800 rpm for 40 minutes to obtain a surface layer slurry.

[0068] The degree of polymerization of the polyvinyl chloride paste resin is 1500.

[0069] The porous filler is prepared by the following steps:

[0070] 1050g Zn(NO3)2·4H2O and 240g terephthalic acid were dissolved in 33L N,N-dimethylformamide at 75°C, stirred for 72 hours, then heated to 110°C to produce precipitation, then cooled to 35°C for crystallization for 24 hours. After crystallization, it was filtered and washed with N,N-dimethylformamide, toluene, and ethanol in sequence. The precipitate was vacuum dried at 55°C to obtain a porous carrier. 600g of the porous carrier was dispersed in 1L methanol, 80g of nano-zinc oxide was added, and then stirred at 65°C until the methanol was completely volatilized to obtain a porous filler.

[0071] Principle of the invention:

[0072] By adding porous fillers to the foaming layer, the specific surface area of ​​the fillers in the foaming layer is increased, so that the bubbles generated when the foaming agent foams are distributed more evenly through the porous structure, forming a denser bubble structure.

[0073] The present invention dissolves nano zinc oxide in methanol so that the nano zinc oxide is incorporated into the porous structure of a porous carrier. The nano zinc oxide can provide more active sites for a foaming agent, significantly affect the decomposition rate of the foaming agent, reduce reaction activation energy, reduce foaming temperature, and increase foaming rate, so that bubbles have sufficient time to be evenly dispersed in the foaming layer. Under the action of the porous filler loaded with nano zinc oxide, the foaming layer of the sports flooring can have dense pores and uniform foaming, thereby improving the toughness of the foaming layer and the shock absorption performance of the sports flooring.

[0074] In the porous carrier structure synthesized with terephthalic acid in the present invention, the carboxyl groups in the terephthalic acid enable the porous carrier to have good dispersibility in the PVC paste resin, thereby allowing the porous carrier to be dispersed in the PVC paste resin. This not only allows the foaming agent to be in uniform contact with the porous carrier in the foaming layer, thereby improving the uniformity of bubble dispersion, but also serves as a filler to improve the wear resistance and mechanical properties of the foaming layer.

[0075] Phthalate plasticizers can easily migrate from PVC products to the PVC surface. In the present invention, the porous filler loaded with nano zinc oxide is dispersed with ethanol and then mixed with the plasticizer, so that part of the plasticizer is filled in the porous filler, thereby reducing the migration of the plasticizer to the surface of the foaming layer.

[0076] Comparative Example 1: The difference from Example 1 is that in the foaming layer slurry, a porous filler is used instead of the porous filler loaded with nano zinc oxide.

[0077] Comparative Example 2: The difference from Example 1 is that in the foaming layer slurry, an equal mass of nano-calcium carbonate is used to replace the porous filler loaded with nano-zinc oxide.

[0078] Comparative Example 3: The difference from Example 1 is that the porous filler is prepared using the following steps:

[0079] In a reactor, 900g of AI(NO3)3·9H20 was dispersed in 7L of distilled water, 170g of terephthalic acid was dissolved in 5L of N,N-dimethylformamide, then added to the reactor and stirred for 30min. The mixture was poured into a high-pressure reactor and hydrothermaled at 180°C for 8h. The substrate was taken out and the surface was rinsed with distilled water and N,N-dimethylformamide in sequence. The substrate was dried at 60°C for 12h to obtain a porous carrier. 500g of the porous carrier was dispersed in 1L of methanol, 40g of nano-zinc oxide was added, and then stirred at 55°C until the methanol was completely volatilized to obtain a porous filler.

[0080] Sources of reagents for Examples and Comparative Examples:

[0081] Polyvinyl chloride paste resin was purchased from Jiangsu Bosite Chemical Technology Co., Ltd.;

[0082] Nano-zinc oxide was purchased from Shanghai Hanlang New Material Technology Co., Ltd.

[0083] Nano calcium carbonate Shanghai Hanlang New Material Technology Co., Ltd.;

[0084] Potassium zinc stabilizer was purchased from Shenzhen Jielitai Plastic Products Co., Ltd.;

[0085] Dioctyl phthalate, azodicarbonamide, Zn(NO3)2·4H2O, Al(NO3)3·9H20, terephthalic acid, and N,N-dimethylformamide were purchased from Sigma Aldrich.

[0086] Performance tests were performed on Examples 1 to 3 and Comparative Examples 1 to 3. The shock energy absorption rate was tested according to EN 14808-2005, and the tensile strength and elongation at break were tested according to GB / T 14833-20206.6. The results are shown in Table 1:

[0087] Table 1

[0088] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Shock energy absorption rate% 19.7 21.2 24.6 15.7 14.4 17.5 Tensile strength MPa 4.32 4.67 4.81 3.18 3.05 3.94 Elongation at break % 154 162 167 141 134 146

[0089] As can be seen from Table 1, the shock energy absorption rate of the PVC sports flooring obtained in Examples 1 to 3 is high compared with that in Comparative Examples 1 to 3, indicating that the bubble structure of the foaming layer prepared in the present invention is good and the shock energy absorption rate is high. In Examples 1 to 3, due to the different foaming thicknesses of the foaming layers, the shock energy absorption rate will also increase with the increase of the foaming thickness. In Comparative Example 1, due to the addition of porous fillers, the specific surface area of ​​the porous filler is larger than that of the nano-calcium carbonate in Comparative Example 2, and the shock energy absorption rate of Comparative Example 1 is slightly larger than that of Comparative Example 2; the test performance of Comparative Example 3 is slightly worse than that of Example 1, indicating that the addition of fillers with porous structures is conducive to the formation of PVC sports flooring with excellent performance. The reason why the test performance of the PVC sports flooring obtained in Comparative Example 3 is poor is that the pore structure of the porous filler is different and the raw materials of the porous filler are different. The porous filler in the embodiment is Zn element. The porous filler formed by Zn element may have a better activation effect on the foaming agent, so that the performance of the PVC sports flooring in Example 1 is better than that of Comparative Example 3.

[0090] The tensile strength and elongation at break obtained in Examples 1 to 3 are greater than those in Comparative Examples 1 and 3, indicating that the PVC sports flooring prepared in the present invention has good toughness and the honeycomb structure formed by foaming is evenly distributed.

[0091] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0092] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A PVC sports flooring, characterized in that: The PVC sports flooring is composed of a base fabric, a foaming layer, a surface layer and a PVC layer from bottom to top; The foaming layer comprises the following components by weight: 80-120 parts of polyvinyl chloride paste resin, 54-68 parts of porous filler, 60-70 parts of plasticizer, 1-2 parts of potassium zinc stabilizer, and 6-10 parts of foaming agent; The porous filler is prepared by the following steps: Dissolve Zn(NO3)2·4H2O and terephthalic acid in N,N-dimethylformamide at 70-75°C, stir for 70-72 hours, then heat to 105-110°C to produce precipitation, then cool to 30-35°C for crystallization for 18-24 hours, filter after crystallization, wash the precipitate with N,N-dimethylformamide, toluene, and ethanol in sequence, and dry in vacuo at 45-55°C to obtain a porous carrier; The porous carrier is dispersed in methanol, nano zinc oxide is added, and then stirred at 55-65° C. until the methanol is completely volatilized to obtain a porous filler.

2. A PVC sports flooring according to claim 1, characterized in that: The surface layer comprises the following components by weight: 80-120 parts of polyvinyl chloride paste resin, 60-70 parts of plasticizer, 1-2 parts of potassium zinc stabilizer, and 30-35 parts of nano calcium carbonate; The PVC layer comprises the following components by weight: 80-100 parts of polyvinyl chloride resin, 55-65 parts of plasticizer and 1-2 parts of potassium zinc stabilizer; The plasticizer is dioctyl phthalate.

3. The PVC sports flooring according to claim 1, characterized in that: The foaming agent is azodicarbonamide.

4. The PVC sports flooring according to claim 1, characterized in that: The mass ratio of the porous carrier to nano zinc oxide is 25-30:2-4.

5. The PVC sports flooring according to claim 1, characterized in that: The usage ratio of the Zn(NO3)2·4H2O, terephthalic acid and N,N-dimethylformamide is 3-3.5g:0.7-0.8g:100-110mL.

6. The method for preparing a PVC sports flooring according to claim 1, characterized in that: The steps include: Step 1: Apply the foaming layer slurry on the base fabric with a coating amount of 800-1200g / m 2 , cure at 140-150℃ for 55-75s, cool, then cure at 80-120g / m 2 Apply the surface slurry on the surface of the solidified foaming layer and solidify it at 140-150℃ for 25-35s to obtain pre-foamed floor glue; Step 2: Send the pre-foamed floor glue into the foaming furnace for foaming, so that the foaming layer is foamed to 4-8mm to obtain the foamed floor glue; Step 3: Mix polyvinyl chloride resin, plasticizer and potassium zinc stabilizer, melt at 180-185℃ and apply it on the surface of the foam floor with a coating machine. The coating amount is 40-60g / m 2 After cooling and shaping, it is cut and embossed to obtain PVC sports flooring.

7. The method for preparing a PVC sports flooring according to claim 6, characterized in that: The foaming layer slurry is prepared by the following steps: The polyvinyl chloride paste resin and the foaming agent are stirred evenly to obtain the foaming resin. The porous filler is dispersed in the slurry barrel with ethanol. After dispersion, the plasticizer and the potassium zinc stabilizer are added. The mixture is heated in a water bath to 50-60°C and stirred until the ethanol is completely volatilized. Then, the foaming resin is added to the slurry barrel and dispersed at a speed of 1200-1600rpm for 1-2h to obtain the foaming layer slurry.

8. The method for preparing a PVC sports flooring according to claim 6, characterized in that: The surface layer slurry is prepared by the following steps: The polyvinyl chloride paste resin, plasticizer, potassium zinc stabilizer and nano calcium carbonate are mixed and dispersed at a speed of 1600-1800 rpm for 20-40 minutes to obtain a surface layer slurry.

9. The method for preparing a PVC sports flooring according to claim 6, characterized in that: The foaming furnace in step 2 includes four zones, the temperature of the first zone is 190-200°C, the temperature of the second zone is 190-210°C, the temperature of the third zone is 200-220°C, and the temperature of the fourth zone is 160-200°C.