High-slip-resistance polyurethane yoga mat surface layer resin with micro-porous structure

Abstract

This invention relates to the field of polyurethane technology, specifically to a high-slip polyurethane yoga mat surface resin with a microporous structure. The surface resin is a polyurethane layer coated on the surface of a thermoplastic elastomer substrate, formed by coagulation and pore formation of raw materials including polycarbonate diol, isophorone diisocyanate, dihydroxy chain extender monomers with sulfobetaine side groups, hydroxyalkyl-terminated polydimethylsiloxane, polyvinylpyrrolidone K30, 1,4-butanediol, and polyethylene glycol dimethyl ether. By chemically fixing hydrophilic groups, confined grafting of siloxane, and stepwise control of the pore-forming sequence, the resulting surface layer can maintain anti-slip stability under sweat conditions for a long time, making it suitable for professional yoga activities.

Description

Technical Field

[0001] This invention relates to the field of polyurethane technology, and more particularly to a high-slip polyurethane yoga mat surface resin with a microporous structure. Background Technology

[0002] Currently, most high-end yoga mats use open-pore polyurethane surfaces to improve sweat absorption and anti-slip properties, but they still have significant drawbacks in actual use. On one hand, traditional open-pore polyurethane surfaces rely on physical pores to absorb sweat, without synergistically regulating the hydrophilicity of the pore walls and surface energy. Sweat easily forms a continuous liquid film on the surface, leading to a significant decrease in the wet dynamic friction coefficient, especially resulting in insufficient anti-slip stability under high temperature and humidity environments. On the other hand, existing processes often introduce hydrophilic components or siloxane modifiers through physical blending. However, hydrophilic components are easily lost through washing and friction, while siloxanes may generate a lubricating effect due to migration, thus reducing surface friction performance and weakening the bond strength between the surface layer and the substrate. This can easily lead to delamination and shedding problems after long-term use.

[0003] Furthermore, the methods for controlling the pore structure are limited. Relying solely on fast-diffusion pore-forming agents can easily lead to large, uneven pore sizes and reduced surface mechanical properties. Conversely, using only slow-diffusion templates can result in low porosity and obstructed sweat penetration channels, prolonging sweat dispersion time. Neither approach can achieve a balance between anti-slip properties, durability, and mechanical stability. Although industry standards set evaluation requirements for the anti-slip performance of yoga mats, existing products still struggle to maintain stable wet grip after repeated washing and long-term wear, failing to meet the needs of professional fitness settings. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose a high-slip polyurethane yoga mat surface resin with a microporous structure, so as to solve the problems in the prior art where the open-pore polyurethane yoga mat surface layer cannot simultaneously achieve rapid sweat dispersion, high wet dynamic friction coefficient and stable performance after long-term cleaning and wear resistance in a sweaty environment, and the surface layer and substrate have insufficient bonding strength.

[0005] To achieve the above objectives, the present invention provides a high-slip polyurethane yoga mat surface resin with a microporous structure, which is a polyurethane surface resin layer coated on the surface of a thermoplastic elastomer yoga mat substrate; the polyurethane surface resin layer is formed by solidifying polyurethane surface resin slurry to form pores.

[0006] The raw materials for preparing the polyurethane surface resin slurry, excluding the solvent, include, by weight: 180-220 parts polycarbonate diol, 62-72 parts isophorone diisocyanate, 10-20 parts dihydroxy chain extender monomer with sulfobetaine side group, 8-15 parts hydroxyalkyl-terminated polydimethylsiloxane, 18-30 parts polyvinylpyrrolidone K30, 9-14 parts 1,4-butanediol and 6-14 parts polyethylene glycol dimethyl ether.

[0007] Preferably, the raw materials used to prepare the polyurethane surface resin slurry, in addition to the solvent, also include 0.6-1.4 parts of an organic bismuth catalyst.

[0008] Preferably, the dihydroxy chain extender monomer with sulfobetaine side group is incorporated into the polyurethane chain segment through its hydroxyl group participating in the chain extension reaction of the isocyanate-terminated polyurethane prepolymer, and the hydroxyalkyl-terminated polydimethylsiloxane is grafted into the polyurethane chain segment through its hydroxyl group reacting with the residual isocyanate group.

[0009] Preferably, the dihydroxy chain extender monomer with sulfobetaine side group is obtained by reacting N-methyldiethanolamine and 1,3-propanesulfonyl lactone; the mass ratio of N-methyldiethanolamine to 1,3-propanesulfonyl lactone is 45-55:46-56.

[0010] Preferably, the polycarbonate diol has a number-average molecular weight of 1800-2200 and a hydroxyl value of 50-60 mgKOH / g; the hydroxyalkyl-terminated polydimethylsiloxane has a number-average molecular weight of 800-1200; and the polyethylene glycol dimethyl ether has a number-average molecular weight of 400-600.

[0011] Preferably, the thickness of the thermoplastic elastomer yoga mat substrate is 3-5 mm, and the surface dyne value of the thermoplastic elastomer yoga mat substrate is not less than 40 mN / m.

[0012] Preferably, the polyurethane surface resin layer is formed by coating the polyurethane surface resin slurry with a wet film thickness of 150-210 μm, followed by coagulation, washing, extraction, and drying.

[0013] Preferably, the polyurethane surface resin layer has an average pore size of 2.14-3.74 μm, a pore size variation coefficient of 17.8%-25.6%, and an open pore porosity of 51.8%-67.5%.

[0014] Preferably, the 5s water contact angle of the polyurethane surface resin layer is 61.2-73.8°, the complete dispersion time of artificial sweat is 8.2s to 22.9s, and the wet dynamic friction coefficient is 1.30-1.66.

[0015] The beneficial effects of this invention are:

[0016] (1) This invention introduces a dihydroxy chain extender monomer with a sulfobetaine side group into the main chain during the chain extension stage of the polyurethane prepolymer, thereby fixing the hydrophilic zwitterionic groups with chemical bonds and preventing the migration and loss of hydrophilic components. Data shows that the 5s water contact angle of Examples 1-5 is 61.2°-73.8°, and the complete dispersion time of artificial sweat is 8.2s-22.9s. This ensures rapid sweat penetration while avoiding excessive hydrophilicity on the surface to form a lubricating film. The wet dynamic friction coefficient reaches 1.30-1.66, which is 42.9%-82.4% higher than that of Comparative Example 1 (0.91).

[0017] (2) By grafting hydroxyalkyl-terminated polydimethylsiloxane with residual isocyanate groups, the low surface energy siloxane segments are confined by the polyurethane network, suppressing the migration lubrication effect. Combined with the stepwise addition of polyvinylpyrrolidone K30 (slow diffusion pore wall template) and polyethylene glycol dimethyl ether (fast diffusion open pore component), a microporous structure with an average pore size of 2.14-3.74 μm and an open pore porosity of 51.8%-67.5% is formed, with a pore size variation coefficient of only 17.8%-25.6%, achieving a balance between pore structure uniformity and connectivity.

[0018] (3) The above synergistic effect gives the surface excellent durability: after 30 cleanings, the wet dynamic friction retention rate is 88.5%-96.2%, and after 1000 wear resistance revolutions, the retention rate is 84.3%-94.6%, and the 180° peel strength is 36.4-42.6N / 25mm, which is 48.0%-73.2% higher than Comparative Example 4 (24.6N / 25mm), solving the problems of rapid decline in anti-slip performance and easy peeling of the surface in the prior art.

[0019] (4) The present invention does not simply obtain anti-slip performance by improving surface hydrophilicity or increasing porosity, but achieves wet anti-slip stability through three mutually cooperating structural controls: First, the dihydroxy chain extender monomer with sulfobetaine side group participates in the polyurethane chain extension reaction through hydroxyl groups, so that the zwitterionic hydrophilic groups are fixed in the polyurethane chain segments in the form of covalent bonds, reducing migration and loss during cleaning and wear processes; Second, hydroxyalkyl-terminated polydimethylsiloxane is grafted onto the polyurethane chain segments in the presence of residual isocyanate groups, so that the siloxane chain segments are confined by the polyurethane network, avoiding free siloxane migration that causes lubrication; Third, polyvinylpyrrolidone K30 and polyethylene glycol dimethyl ether are added at different stages, so that the former mainly serves as a slow diffusion pore wall template and the latter mainly serves as a fast diffusion opening component, forming a microporous structure with small pore size, narrow distribution and suitable connectivity. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0021] Raw material source and specifications:

[0022] The polycarbonate glycol used is Asahi Kasei Corporation's DURANOL T5652, with a number average molecular weight of 2000 and a hydroxyl value of 55 mgKOH / g; the hydroxyalkyl-terminated polydimethylsiloxane used is Gelest DMS-C15, with a number average molecular weight of 1000; the polyethylene glycol dimethyl ether used is Sigma-Aldrich 445886, with a number average molecular weight of 500; the organic bismuth catalyst used is Shepherd Chemical BiCAT 8108, with a bismuth content of 20.0%; the thermoplastic elastomer yoga mat substrate is a commercially available polyolefin thermoplastic elastomer sheet with a thickness of 4 mm, which is corona treated before coating until the surface dyne value is not less than 40 mN / m.

[0023] The isocyanate group mass fractions mentioned in the following steps are all values ​​obtained by back titration of di-n-butylamine after sampling, and converted according to the mass of reactive solids after deducting anhydrous N,N-dimethylacetamide and dimethyl sulfoxide.

[0024] Example 1:

[0025] Step 1: Dry nitrogen gas was introduced into a dried reaction vessel, and 50g of N-methyldiethanolamine and 220g of anhydrous acetonitrile were added. The stirring speed was controlled at 300rpm, and the system was heated to 45℃. Separately, 51g of 1,3-propanesulfonyl lactone was added to 80g of anhydrous acetonitrile and stirred at 45℃ for 20min. Then, it was added dropwise to the reaction vessel over 60min. After the dropwise addition was completed, the system was heated to 50℃ and reacted for 10h. After the reaction was completed, the temperature was lowered to 10℃ and maintained for 1h. The solid was collected by filtration, washed twice with 120g of ethyl acetate, and then dried under vacuum at 60℃ and -90kPa for 8h to obtain a dihydroxy chain-extended monomer with a sulfobetaine side group.

[0026] Step 2: Add 200g of polycarbonate diol to the reaction vessel and dehydrate it at 110℃ and -90kPa for 2 hours. After cooling to 75℃, add 260g of anhydrous N,N-dimethylacetamide, 67g of isophorone diisocyanate, and 1g of organic bismuth catalyst. Stir at 300rpm under dry nitrogen protection, control the temperature at 80℃, and react. Use di-n-butylamine back titration to detect the reaction. When the mass fraction of isocyanate groups based on the mass of reactive solids is 6.5%, proceed to the next step.

[0027] Step 3: Take 15g of the dihydroxy chain extender monomer with sulfobetaine side group obtained in Step 1, add it to 90g of dimethyl sulfoxide, and stir at 60℃ for 30min to obtain a monomer solution; add the obtained monomer solution to the isocyanate-terminated polyurethane prepolymer obtained in Step 2 within 40min, control the system temperature at 65℃ and react; use di-n-butylamine back titration method to detect, when the mass fraction of isocyanate group based on reactive solids decreases to 4.5%, proceed to the next step.

[0028] Step 4: Add 12g of hydroxyalkyl-terminated polydimethylsiloxane and 30g of anhydrous N,N-dimethylacetamide to the reaction solution obtained in Step 3, and react at 65°C. The reaction is detected by di-n-butylamine back titration. When the mass fraction of isocyanate groups based on the mass of reactive solids decreases to 3.4%, add 24g of polyvinylpyrrolidone K30 dried at 80°C and -90kPa for 4h and 80g of anhydrous N,N-dimethylacetamide, and continue stirring at 60°C for 60min.

[0029] Step 5: Mix 12g of 1,4-butanediol with 30g of anhydrous N,N-dimethylacetamide, add the mixture to the reaction solution obtained in Step 4 at 55℃ for 30 min, and continue the reaction at 55℃ for 3 h; after the isocyanate group is not detected by di-n-butylamine back titration, add 10g of polyethylene glycol dimethyl ether and 30g of anhydrous N,N-dimethylacetamide, stir for 30 min, filter through a 200-mesh filter, and degas at -80kPa for 20 min to obtain polyurethane surface resin slurry.

[0030] Step 6: Take 300g of the polyurethane surface resin slurry obtained in Step 5 and apply it to the surface of a thermoplastic elastomer yoga mat substrate with a thickness of 4mm and a surface dyne value of not less than 40mN / m with a wet film thickness of 180μm. Place the coated substrate in an environment of 25℃ and 45% relative humidity for pre-evaporation for 90s, and then immerse it in a coagulation bath at 20℃ for 3min. The coagulation bath consists of 1000g of deionized water and 50g of anhydrous N,N-dimethylacetamide. Then, transfer it to 2000g of deionized water at 30℃ and soak it for 30min, replacing the 2000g of deionized water every 10min.

[0031] Step 7: Extract the coated substrate obtained in Step 6 in 3000g of deionized water at 50℃ for 2 hours, replacing the 3000g of deionized water every 30 minutes; after extraction, dry in hot air at 80℃ for 2 hours, then vacuum dry at 60℃ and -90kPa for 6 hours, and finally place in an environment of 23℃ and 50% relative humidity for 24 hours to obtain a high anti-slip polyurethane yoga mat surface resin with a microporous structure.

[0032] Example 2:

[0033] Step 1: Dry nitrogen gas was introduced into a dried reaction vessel, and 50g of N-methyldiethanolamine and 220g of anhydrous acetonitrile were added. The stirring speed was controlled at 300rpm, and the system was heated to 45℃. Separately, 51g of 1,3-propanesulfonyl lactone was added to 80g of anhydrous acetonitrile and stirred at 45℃ for 20min. Then, it was added dropwise to the reaction vessel over 60min. After the dropwise addition was completed, the system was heated to 50℃ and reacted for 10h. After the reaction was completed, the temperature was lowered to 10℃ and maintained for 1h. The solid was collected by filtration, washed twice with 120g of ethyl acetate, and then dried under vacuum at 60℃ and -90kPa for 8h to obtain a dihydroxy chain-extended monomer with a sulfobetaine side group.

[0034] Step 2: Add 190g of polycarbonate diol to the reaction vessel and dehydrate it at 110℃ and -90kPa for 2 hours. After cooling to 75℃, add 250g of anhydrous N,N-dimethylacetamide, 64g of isophorone diisocyanate, and 0.8g of organic bismuth catalyst. Stir at 300rpm under dry nitrogen protection and control the temperature at 80℃ for reaction. Use di-n-butylamine back titration to detect the reaction. When the mass fraction of isocyanate groups based on the mass of reactive solids is 6.3%, proceed to the next step.

[0035] Step 3: Take 10g of the dihydroxy chain extender monomer with sulfobetaine side group obtained in Step 1, add it to 70g of dimethyl sulfoxide, and stir at 60℃ for 30min to obtain a monomer solution; add the obtained monomer solution to the isocyanate-terminated polyurethane prepolymer obtained in Step 2 within 35min, control the system temperature at 65℃ and react; use di-n-butylamine back titration method to detect, when the mass fraction of isocyanate group based on reactive solids decreases to 4.8%, proceed to the next step.

[0036] Step 4: Add 8g of hydroxyalkyl-terminated polydimethylsiloxane and 25g of anhydrous N,N-dimethylacetamide to the reaction solution obtained in Step 3, and react at 65°C. The reaction is detected by di-n-butylamine back titration. When the mass fraction of isocyanate groups based on the mass of reactive solids decreases to 4.3%, add 18g of polyvinylpyrrolidone K30 dried at 80°C and -90kPa for 4h and 70g of anhydrous N,N-dimethylacetamide, and continue stirring at 60°C for 60min.

[0037] Step 5: Mix 13g of 1,4-butanediol with 30g of anhydrous N,N-dimethylacetamide, add the mixture to the reaction solution obtained in Step 4 at 55℃ for 30 min, and continue the reaction at 55℃ for 3 h; after the isocyanate group is not detected by di-n-butylamine back titration, add 6g of polyethylene glycol dimethyl ether and 25g of anhydrous N,N-dimethylacetamide, stir for 30 min, filter through a 200-mesh filter, and degas at -80kPa for 20 min to obtain polyurethane surface resin slurry.

[0038] Step 6: Take 300g of the polyurethane surface resin slurry obtained in Step 5 and apply it to the surface of a thermoplastic elastomer yoga mat substrate with a thickness of 4mm and a surface dyne value of not less than 40mN / m with a wet film thickness of 150μm. Place the coated substrate in an environment of 25℃ and 45% relative humidity for 70s to pre-evaporate, and then immerse it in a coagulation bath at 20℃ for 3min. The coagulation bath consists of 1000g of deionized water and 30g of anhydrous N,N-dimethylacetamide. Then, transfer it to 2000g of deionized water at 30℃ and soak it for 30min, replacing the 2000g of deionized water every 10min.

[0039] Step 7: Extract the coated substrate obtained in Step 6 in 3000g of deionized water at 50℃ for 2 hours, replacing the 3000g of deionized water every 30 minutes; after extraction, dry in hot air at 80℃ for 2 hours, then vacuum dry at 60℃ and -90kPa for 6 hours, and finally place in an environment of 23℃ and 50% relative humidity for 24 hours to obtain a high anti-slip polyurethane yoga mat surface resin with a microporous structure.

[0040] Example 3:

[0041] Step 1: Dry nitrogen gas was introduced into a dried reaction vessel, and 50g of N-methyldiethanolamine and 220g of anhydrous acetonitrile were added. The stirring speed was controlled at 300rpm, and the system was heated to 45℃. Separately, 51g of 1,3-propanesulfonyl lactone was added to 80g of anhydrous acetonitrile and stirred at 45℃ for 20min. Then, it was added dropwise to the reaction vessel over 60min. After the dropwise addition was completed, the system was heated to 50℃ and reacted for 10h. After the reaction was completed, the temperature was lowered to 10℃ and maintained for 1h. The solid was collected by filtration, washed twice with 120g of ethyl acetate, and then dried under vacuum at 60℃ and -90kPa for 8h to obtain a dihydroxy chain-extended monomer with a sulfobetaine side group.

[0042] Step 2: Add 210g of polycarbonate diol to the reaction vessel and dehydrate it at 110℃ and -90kPa for 2 hours. After cooling to 75℃, add 275g of anhydrous N,N-dimethylacetamide, 70g of isophorone diisocyanate, and 1.2g of organic bismuth catalyst. Stir at 300rpm under dry nitrogen protection and control the temperature at 80℃ for reaction. Use di-n-butylamine back titration to detect the reaction. When the mass fraction of isocyanate groups based on the mass of reactive solids is 6.3%, proceed to the next step.

[0043] Step 3: Take 20g of the dihydroxy chain extender monomer with sulfobetaine side group obtained in Step 1, add it to 105g of dimethyl sulfoxide, and stir at 60℃ for 30min to obtain a monomer solution; add the obtained monomer solution to the isocyanate-terminated polyurethane prepolymer obtained in Step 2 within 45min, control the system temperature at 65℃ and react; use di-n-butylamine back titration method to detect, when the mass fraction of isocyanate group based on reactive solids decreases to 3.6%, proceed to the next step.

[0044] Step 4: Add 15g of hydroxyalkyl-terminated polydimethylsiloxane and 35g of anhydrous N,N-dimethylacetamide to the reaction solution obtained in Step 3, react at 65℃, and detect the reaction by di-n-butylamine back titration. When the mass fraction of isocyanate groups based on the mass of reactive solids drops to 3.0%, add 28g of polyvinylpyrrolidone K30 dried at 80℃ and -90kPa for 4h and 90g of anhydrous N,N-dimethylacetamide, and continue stirring at 60℃ for 60min.

[0045] Step 5: Mix 10g of 1,4-butanediol with 30g of anhydrous N,N-dimethylacetamide, add the mixture to the reaction solution obtained in Step 4 at 55℃ for 30 min, and continue the reaction at 55℃ for 3 h; after the isocyanate group is not detected by di-n-butylamine back titration, add 12g of polyethylene glycol dimethyl ether and 30g of anhydrous N,N-dimethylacetamide, stir for 30 min, filter through a 200-mesh filter, and degas at -80kPa for 20 min to obtain polyurethane surface resin slurry.

[0046] Step 6: Take 300g of the polyurethane surface resin slurry obtained in Step 5 and apply it to the surface of a thermoplastic elastomer yoga mat substrate with a thickness of 4mm and a surface dyne value of not less than 40mN / m with a wet film thickness of 210μm. Place the coated substrate in an environment of 25℃ and 45% relative humidity for pre-evaporation for 110s, and then immerse it in a coagulation bath at 18℃ for 4min. The coagulation bath consists of 1000g of deionized water and 70g of anhydrous N,N-dimethylacetamide. Then, transfer it to 2000g of deionized water at 30℃ and soak it for 30min, replacing the 2000g of deionized water every 10min.

[0047] Step 7: Extract the coated substrate obtained in Step 6 in 3000g of deionized water at 50℃ for 2 hours, replacing the 3000g of deionized water every 30 minutes; after extraction, dry in hot air at 80℃ for 2 hours, then vacuum dry at 60℃ and -90kPa for 6 hours, and finally place in an environment of 23℃ and 50% relative humidity for 24 hours to obtain a high anti-slip polyurethane yoga mat surface resin with a microporous structure.

[0048] Example 4:

[0049] Step 1: Dry nitrogen gas was introduced into a dried reaction vessel, and 50g of N-methyldiethanolamine and 220g of anhydrous acetonitrile were added. The stirring speed was controlled at 300rpm, and the system was heated to 45℃. Separately, 51g of 1,3-propanesulfonyl lactone was added to 80g of anhydrous acetonitrile and stirred at 45℃ for 20min. Then, it was added dropwise to the reaction vessel over 60min. After the dropwise addition was completed, the system was heated to 50℃ and reacted for 10h. After the reaction was completed, the temperature was lowered to 10℃ and maintained for 1h. The solid was collected by filtration, washed twice with 120g of ethyl acetate, and then dried under vacuum at 60℃ and -90kPa for 8h to obtain a dihydroxy chain-extended monomer with a sulfobetaine side group.

[0050] Step 2: Add 180g of polycarbonate diol to the reaction vessel and dehydrate it at 110℃ and -90kPa for 2 hours. After cooling to 75℃, add 240g of anhydrous N,N-dimethylacetamide, 62g of isophorone diisocyanate, and 0.9g of organic bismuth catalyst. Stir at 300rpm under dry nitrogen protection and control the temperature at 80℃ for reaction. Use di-n-butylamine back titration to detect the reaction. When the mass fraction of isocyanate groups based on the mass of reactive solids is 6.5%, proceed to the next step.

[0051] Step 3: Take 12g of the dihydroxy chain extender monomer with sulfobetaine side group obtained in Step 1, add it to 80g of dimethyl sulfoxide, and stir at 60℃ for 30min to obtain a monomer solution; add the obtained monomer solution to the isocyanate-terminated polyurethane prepolymer obtained in Step 2 within 40min, control the system temperature at 65℃ and react; use di-n-butylamine back titration method to detect, when the mass fraction of isocyanate group based on reactive solids decreases to 4.6%, proceed to the next step.

[0052] Step 4: Add 10g of hydroxyalkyl-terminated polydimethylsiloxane and 30g of anhydrous N,N-dimethylacetamide to the reaction solution obtained in Step 3, and react at 65°C. The reaction is detected by di-n-butylamine back titration. When the mass fraction of isocyanate groups based on the mass of reactive solids decreases to 4.1%, add 30g of polyvinylpyrrolidone K30 dried at 80°C and -90kPa for 4h and 95g of anhydrous N,N-dimethylacetamide, and continue stirring at 60°C for 60min.

[0053] Step 5: Mix 11.7g of 1,4-butanediol with 30g of anhydrous N,N-dimethylacetamide, add the mixture to the reaction solution obtained in Step 4 at 55℃ for 30min, and continue the reaction at 55℃ for 3h. After the isocyanate group is not detected by di-n-butylamine back titration, add 8g of polyethylene glycol dimethyl ether and 30g of anhydrous N,N-dimethylacetamide, stir for 30min, filter through a 200-mesh filter, and degas at -80kPa for 20min to obtain polyurethane surface resin slurry.

[0054] Step 6: Take 300g of the polyurethane surface resin slurry obtained in Step 5 and apply it to the surface of a thermoplastic elastomer yoga mat substrate with a thickness of 4mm and a surface dyne value of not less than 40mN / m with a wet film thickness of 180μm. Place the coated substrate in an environment of 25℃ and 45% relative humidity for 90s to pre-evaporate, and then immerse it in a coagulation bath at 22℃ for 2.5min. The coagulation bath consists of 1000g of deionized water and 50g of anhydrous N,N-dimethylacetamide. Then, transfer it to 2000g of deionized water at 30℃ and soak it for 30min, replacing the 2000g of deionized water every 10min.

[0055] Step 7: Extract the coated substrate obtained in Step 6 in 3000g of deionized water at 50℃ for 2 hours, replacing the 3000g of deionized water every 30 minutes; after extraction, dry in hot air at 80℃ for 2 hours, then vacuum dry at 60℃ and -90kPa for 6 hours, and finally place in an environment of 23℃ and 50% relative humidity for 24 hours to obtain a high anti-slip polyurethane yoga mat surface resin with a microporous structure.

[0056] Example 5:

[0057] Step 1: Dry nitrogen gas was introduced into a dried reaction vessel, and 50g of N-methyldiethanolamine and 220g of anhydrous acetonitrile were added. The stirring speed was controlled at 300rpm, and the system was heated to 45℃. Separately, 51g of 1,3-propanesulfonyl lactone was added to 80g of anhydrous acetonitrile and stirred at 45℃ for 20min. Then, it was added dropwise to the reaction vessel over 60min. After the dropwise addition was completed, the system was heated to 50℃ and reacted for 10h. After the reaction was completed, the temperature was lowered to 10℃ and maintained for 1h. The solid was collected by filtration, washed twice with 120g of ethyl acetate, and then dried under vacuum at 60℃ and -90kPa for 8h to obtain a dihydroxy chain-extended monomer with a sulfobetaine side group.

[0058] Step 2: Add 220g of polycarbonate diol to the reaction vessel and dehydrate it at 110℃ and -90kPa for 2 hours. After cooling to 75℃, add 280g of anhydrous N,N-dimethylacetamide, 72g of isophorone diisocyanate, and 1.4g of organic bismuth catalyst. Stir at 300rpm under dry nitrogen protection and control the temperature at 80℃ for reaction. Use di-n-butylamine back titration to detect the reaction. When the mass fraction of isocyanate groups based on the mass of reactive solids is 6.1%, proceed to the next step.

[0059] Step 3: Take 18g of the dihydroxy chain extender monomer with sulfobetaine side group obtained in Step 1, add it to 100g of dimethyl sulfoxide, and stir at 60℃ for 30min to obtain a monomer solution; add the obtained monomer solution to the isocyanate-terminated polyurethane prepolymer obtained in Step 2 within 45min, control the system temperature at 65℃ and react; use di-n-butylamine back titration to detect the isocyanate group mass fraction when it drops to 3.8% based on the mass of reactive solids, proceed to the next step.

[0060] Step 4: Add 14g of hydroxyalkyl-terminated polydimethylsiloxane and 35g of anhydrous N,N-dimethylacetamide to the reaction solution obtained in Step 3, and react at 65°C. The reaction is detected by di-n-butylamine back titration. When the mass fraction of isocyanate groups based on the mass of reactive solids decreases to 3.2%, add 22g of polyvinylpyrrolidone K30 dried at 80°C and -90kPa for 4h and 85g of anhydrous N,N-dimethylacetamide, and continue stirring at 60°C for 60min.

[0061] Step 5: Mix 11.3g of 1,4-butanediol with 30g of anhydrous N,N-dimethylacetamide, add the mixture to the reaction solution obtained in Step 4 at 55℃ for 30 min, and continue the reaction at 55℃ for 3 h; after the isocyanate group is not detected by di-n-butylamine back titration, add 14g of polyethylene glycol dimethyl ether and 35g of anhydrous N,N-dimethylacetamide, stir for 30 min, filter through a 200-mesh filter, and degas at -80kPa for 20 min to obtain polyurethane surface resin slurry.

[0062] Step 6: Take 300g of the polyurethane surface resin slurry obtained in Step 5 and apply it to the surface of a thermoplastic elastomer yoga mat substrate with a thickness of 4mm and a surface dyne value of not less than 40mN / m with a wet film thickness of 200μm. Place the coated substrate in an environment of 25℃ and 45% relative humidity for 100s to pre-evaporate, and then immerse it in a coagulation bath at 20℃ for 3.5min. The coagulation bath consists of 1000g of deionized water and 60g of anhydrous N,N-dimethylacetamide. Then, transfer it to 2000g of deionized water at 30℃ and soak it for 30min, replacing the 2000g of deionized water every 10min.

[0063] Step 7: Extract the coated substrate obtained in Step 6 in 3000g of deionized water at 50℃ for 2 hours, replacing the 3000g of deionized water every 30 minutes; after extraction, dry in hot air at 80℃ for 2 hours, then vacuum dry at 60℃ and -90kPa for 6 hours, and finally place in an environment of 23℃ and 50% relative humidity for 24 hours to obtain a high anti-slip polyurethane yoga mat surface resin with a microporous structure.

[0064] Comparative Example 1:

[0065] The difference from Example 1 is that, in step 3, instead of adding 15g of the dihydroxy chain extender monomer with sulfobetaine side group obtained in step 1, 5.6g of 1,4-butanediol is added to 90g of dimethyl sulfoxide, stirred at 60°C for 30min, and then added to the isocyanate-terminated polyurethane prepolymer obtained in step 2 within 40min. The system temperature is controlled at 65°C and the reaction is carried out. The reaction is detected by di-n-butylamine back titration. When the mass fraction of isocyanate group based on reactive solids decreases to 4.5%, the reaction proceeds to step 4. The remaining conditions are the same as in Example 1.

[0066] Comparative Example 2:

[0067] The difference from Example 1 is as follows: In step 3, instead of adding 15g of the dihydroxy chain extender monomer with sulfobetaine side group obtained in step 1, 5.6g of 1,4-butanediol is added to 90g of dimethyl sulfoxide, stirred at 60°C for 30min, and then added to the isocyanate-terminated polyurethane prepolymer obtained in step 2 within 40min. The system temperature is controlled at 65°C and the reaction is carried out. The reaction is detected by di-n-butylamine back titration. When the mass fraction of isocyanate group based on reactive solids decreases to 4.5%, the reaction proceeds to step 4. In step 5, after adding 10g of polyethylene glycol dimethyl ether and 30g of anhydrous N,N-dimethylacetamide, 15g of the dihydroxy chain extender monomer with sulfobetaine side group obtained in step 1 is added, and the stirring continues for 30min. The remaining conditions are the same as in Example 1.

[0068] Comparative Example 3:

[0069] The difference from Example 1 is that, in step 4, instead of adding 12g of hydroxyalkyl-terminated polydimethylsiloxane, 1.1g of 1,4-butanediol and 30g of anhydrous N,N-dimethylacetamide are mixed and added to the reaction solution obtained in step 3. The reaction is carried out at 65°C, and the reaction is detected by di-n-butylamine back titration. When the mass fraction of isocyanate groups based on the mass of reactive solids drops to 3.4%, 24g of polyvinylpyrrolidone K30 dried at 80°C and -90kPa for 4h and 80g of anhydrous N,N-dimethylacetamide are added, and the mixture is stirred at 60°C for 60min. The remaining conditions are the same as in Example 1.

[0070] Comparative Example 4:

[0071] The difference from Example 1 is as follows: In step 4, instead of adding 12g of hydroxyalkyl-terminated polydimethylsiloxane, 1.1g of 1,4-butanediol and 30g of anhydrous N,N-dimethylacetamide are mixed and added to the reaction solution obtained in step 3. The reaction is carried out at 65°C, and the reaction is detected by di-n-butylamine back titration. When the mass fraction of isocyanate groups based on the mass of reactive solids drops to 3.4%, 24g of polyvinylpyrrolidone K30 dried at 80°C and -90kPa for 4h and 80g of anhydrous N,N-dimethylacetamide are added, and the mixture is stirred at 60°C for 60min. In step 5, after adding 10g of polyethylene glycol dimethyl ether and 30g of anhydrous N,N-dimethylacetamide, 12g of hydroxyalkyl-terminated polydimethylsiloxane is added, and the mixture is stirred for 30min. The remaining conditions are the same as in Example 1.

[0072] Comparative Example 5:

[0073] The difference from Example 1 is that: 24g of polyvinylpyrrolidone K30 is not added in step 4; the amount of polyethylene glycol dimethyl ether in step 5 is adjusted from 10g to 34g; the other conditions are the same as in Example 1.

[0074] Comparative Example 6:

[0075] The difference from Example 1 is that the amount of polyvinylpyrrolidone K30 in step 4 is adjusted from 24g to 34g; 10g of polyethylene glycol dimethyl ether is not added in step 5; the other conditions are the same as in Example 1.

[0076] Comparative Example 7:

[0077] The difference from Example 1 is that in step 4, 10g of polyethylene glycol dimethyl ether is added at the same time as 24g of polyvinylpyrrolidone K30 dried at 80°C and -90kPa for 4h and 80g of anhydrous N,N-dimethylacetamide; in step 5, polyethylene glycol dimethyl ether is not added; the other conditions are the same as in Example 1.

[0078] Sample preparation before testing: The coated substrates obtained in Examples 1-5 and Comparative Examples 1-7 were cut into test samples. Before cutting, all samples were placed in an environment of 23°C and 50% relative humidity for 24 hours. The sample size for pore structure, water contact angle and artificial sweat dispersion tests was 50mm×50mm; the sample size for friction coefficient tests was 100mm×200mm; the sample size for wear-resistant friction coefficient tests was 100mm×100mm; and the sample size for 180° peel strength tests was 25mm×200mm. The polyurethane surface resin slurry obtained in step 5 of each example and comparative example was separately coated onto the surface of a polyester film after demolding treatment with a wet film thickness of 180μm. A free surface film was prepared according to the coagulation, washing, extraction and drying conditions in steps 6 and 7, and used as a pore structure test sample. All tests were conducted using Examples 1-5 and Comparative Examples 1-7 as the same batch of test subjects. For each test item, five samples were tested in parallel, and the arithmetic mean was taken as the test result. The retention rate was calculated by multiplying the ratio of the wet dynamic friction coefficient after treatment to the wet dynamic friction coefficient before treatment by 100%.

[0079] Micropore structure testing: The test was conducted according to GB / T 21650.1-2008 "Determination of Pore Size Distribution and Porosity of Solid Materials by Mercury Intrusion Porosimetry and Gas Adsorption Methods - Part 1: Mercury Intrusion Porosimetry". Free surface membrane was taken, cut into 10mm × 10mm pieces, vacuum dried at 60℃ and -90kPa for 4 hours, and then cooled in a desiccator for 30 minutes. 0.20g of each sample was weighed. The pore size distribution and open porosity were tested using a mercury intrusion porosimetry instrument. Before the test, the sample chamber was evacuated to a pressure not exceeding 50Pa. The equilibrium time for the low-pressure section was set to 30s, and the equilibrium time for the high-pressure section was set to 60s. The contact angle was input as 130°, and the mercury surface tension was input as 0.485N / m. After the test, the average pore size, pore size variation coefficient, and open porosity were output.

[0080] Water contact angle test: The test was conducted according to GB / T 30693-2014 "Measurement of Water Contact Angle of Plastic Films". A 50mm × 50mm coated substrate sample was fixed on the horizontal sample stage of the contact angle measuring instrument with the polyurethane surface facing upwards. Deionized water was used as the test liquid, with a single drop volume of 5μL and the dropper tip positioned 5mm above the sample surface. Timing began after the droplet contacted the sample surface, and the static water contact angle was recorded after 5 seconds. Each sample was tested 5 times at different locations, with a minimum distance of 10mm between each test location.

[0081] Artificial sweat dispersion time test: The artificial sweat was prepared according to the test method for acidic sweat in GB / T 3922-2013 "Textiles - Tests for Color Fastness - Color Fastness to Perspiration". Specifically, 5.0g sodium chloride, 0.5g L-histidine hydrochloride monohydrate, and 2.2g sodium dihydrogen phosphate dihydrate were added to 1000g deionized water. After stirring and dissolving, the pH was adjusted to 5.5 with 0.1mol / L sodium hydroxide solution. A 50mm × 50mm coated substrate sample was fixed on a horizontal sample stage with the polyurethane surface facing upwards. 20μL of artificial sweat was dropped into the center of the sample using a pipette, and video recording was started simultaneously. The ambient temperature was 23℃ and the relative humidity was 50%. The endpoint of complete dispersion was defined as the disappearance of the highlights on the surface of the artificial sweat droplet and the change in the edge diameter not exceeding 5% within 5 seconds. The time from droplet addition to complete dispersion was recorded.

[0082] Dry and wet dynamic friction coefficient tests: The anti-slip performance evaluation object was based on TY / T 3802.1-2024 "Requirements and Test Methods for Fitness and Yoga Equipment Part 1: Yoga Mats," and the test was conducted in accordance with GB / T 10006-2021 "Determination of the Coefficient of Friction for Plastic Films and Sheets." A 100mm × 200mm coated substrate sample was fixed on the horizontal platform of the friction coefficient meter, with the polyurethane surface facing upwards. A silicone rubber sheet with a Shore A hardness of 45 (63mm × 63mm) was fixed to the bottom of the slider. The total mass of the slider was 200g, the traction speed was 100mm / min, and the test stroke was 100mm. No liquid was added to the sample surface during the dry test. During the wet test, 1.0mL of artificial sweat was evenly dripped onto the test area, and a polytetrafluoroethylene scraper was used to lightly scrape it once to cover the test stroke area. After standing for 30 seconds, the test was conducted immediately. Each sample was tested in parallel five times, and the dry and wet dynamic friction coefficients were recorded.

[0083] Wet dynamic friction coefficient retention rate test after cleaning: A 100mm×200mm coated substrate sample was immersed in deionized water at 23℃ for 30s. After removal, 1.0mL of 0.5% (w / w) neutral detergent aqueous solution was added to the polyurethane surface. A 200g flat pressure block with a clean gauze-covered bottom was used to wipe the sample back and forth 20 times along its length. The sample was then rinsed with deionized water at 23℃ for 30s and dried in hot air at 50℃ for 30min, which was recorded as one cleaning cycle. After 30 consecutive cleaning cycles, the sample was placed in an environment of 23℃ and 50% relative humidity for 24h, and the wet dynamic friction coefficient was tested again. The wet dynamic friction coefficient retention rate after cleaning was calculated as the ratio of the wet dynamic friction coefficient after cleaning to the wet dynamic friction coefficient before cleaning multiplied by 100%.

[0084] Test for retention rate of wet dynamic friction coefficient after wear resistance: The test was conducted according to GB / T 1768-2006 "Determination of Abrasion Resistance of Paints and Varnishes - Rotating Rubber Grinding Wheel Method". A 100mm × 100mm coated substrate sample was fixed on the turntable of the wear testing machine with the polyurethane surface facing upwards. A CS-10 rubber grinding wheel was used, with a load of 500g on each wheel, a rotation speed of 60r / min, and a wear cycle of 1000 revolutions. After wear, surface debris was removed with a soft brush, followed by rinsing with 23℃ deionized water for 10s, drying in 50℃ hot air for 30min, and then placing in an environment of 23℃ and 50% relative humidity for 24h. The wet dynamic friction coefficient was then tested. The retention rate of the wet dynamic friction coefficient after wear resistance was calculated as the ratio of the wet dynamic friction coefficient after wear resistance to the wet dynamic friction coefficient before wear resistance multiplied by 100%.

[0085] 180° Peel Strength Test between Surface and Substrate: The test was conducted according to GB / T 8808-1988 "Peel Test Method for Flexible Composite Plastic Materials". A 25mm × 200mm coated substrate sample was pre-peeled 30mm along the interface between the polyurethane surface and the thermoplastic elastomer yoga mat substrate using a blade. The polyurethane surface and the thermoplastic elastomer yoga mat substrate were then clamped together, maintaining a peel angle of 180°. The tensile speed was 300mm / min, and the average peel force within the stable peel range was recorded. The result is expressed as N / 25mm. Five samples were tested for each sample, and the arithmetic mean was taken.

[0086] Table 1 Performance Test Results

[0087] sample Average pore size / μm Pore ​​size variation coefficient / % Porosity (%) 5s water contact angle / ° Complete dispersion time of artificial sweat / s Dry dynamic friction coefficient wet dynamic friction coefficient Wet dynamic friction retention rate after cleaning / % Wear-resistant wet dynamic friction retention rate / % 180° peel strength / N / 25mm Example 1 2.86 21.7 58.6 68.4 14.8 1.61 1.53 94.8 90.7 39.2 Example 2 2.14 25.6 51.8 73.8 22.9 1.45 1.3 88.5 84.3 36.4 Example 3 3.18 19.4 63.7 65.9 11.7 1.68 1.66 95.6 92.8 42.6 Example 4 2.42 17.8 60.9 61.2 10.6 1.62 1.6 96.2 94.6 38.5 Example 5 3.74 23.3 67.5 67.6 8.2 1.59 1.56 93.1 88.4 37.9 Comparative Example 1 2.79 29.8 55.4 87.5 58.4 1.35 0.91 75.4 70.8 35.5 Comparative Example 2 3.05 38.6 57.8 80.3 38.6 1.38 1.05 63.2 58.9 29.8 Comparative Example 3 2.68 27.5 56.7 54.8 12.2 1.52 1.12 82.1 78.4 36.9 Comparative Example 4 3.12 42.9 59.2 94.2 65.3 1.19 0.78 60.5 53.7 24.6 Comparative Example 5 4.86 57.4 72.6 71.5 21.8 1.46 1.18 69.8 61.4 22.8 Comparative Example 6 1.63 32.1 38.5 58.6 43.7 1.49 1.08 84.7 82.2 40.8 Comparative Example 7 3.47 36.8 62.4 70.2 26.9 1.50 1.22 78.5 72.6 32.1

[0088] As can be seen from Table 1, in Comparative Example 1, although a certain open-cell structure can still be formed without the introduction of immobilized sulfobetaine side groups into the polyurethane main chain, the water contact angle reaches 87.5° in 5s, the complete dispersion time of artificial sweat is extended to 58.4s, and the wet dynamic friction coefficient is only 0.91. This indicates that it is difficult to maintain a stable anti-slip effect in the presence of sweat by simply relying on the phase transformation pore structure of polyurethane.

[0089] Comparative Example 2 changed the addition method of sulfobetaine dihydroxy chain extender monomer to a post-addition method, which failed to fully participate in the chain extension reaction of isocyanate-terminated prepolymer. Its initial water contact angle and sweat dispersion time were improved compared with Comparative Example 1, but the wet dynamic friction retention rate after washing and wear resistance was only 63.2% and 58.9%, respectively. This indicates that free or weakly bound hydrophilic components are easy to migrate or be lost during washing, extraction or friction, and it is difficult to form stable hydrophilic sites on the pore wall.

[0090] In Comparative Example 3, without the addition of hydroxyalkyl-terminated polydimethylsiloxane, although the complete dispersion time of artificial sweat was shortened to 12.2s, the wet dynamic friction coefficient was only 1.12. It is speculated that the excessive hydrophilicity of its surface makes it easier to form a continuous liquid film, which weakens the effective friction of the skin of the hands and feet or the silicone rubber contact interface. In Comparative Example 4, the hydroxyalkyl-terminated polydimethylsiloxane was added later. The water contact angle increased to 94.2° in 5s, and the wet dynamic friction coefficient decreased to 0.78. This indicates that the unreacted grafted siloxane component is prone to surface migration or lubrication effect, which is not conducive to wet anti-slip and durability maintenance.

[0091] Comparative Example 5, without the addition of polyvinylpyrrolidone K30 but with increased polyethylene glycol dimethyl ether (PEG) content, achieved an open-cell porosity of 72.6%, but the average pore size increased to 4.86 μm, the coefficient of variation of pore size increased to 57.4%, and the 180° peel strength decreased to 22.8 N / 25 mm. This indicates that relying solely on fast-diffusion open-cell components results in a coarse and unevenly distributed pore structure. Comparative Example 6, by increasing polyvinylpyrrolidone K30 without adding PEG dimethyl ether, reduced the average pore size to 1.6 μm. With a pore size of 3μm and an open-pore porosity of only 38.5%, the artificial sweat dispersion time was extended to 43.7s, indicating that although a single slow-diffusion template is beneficial to the film density and peel strength, it is not conducive to the formation of fully interconnected sweat migration channels. In Comparative Example 7, when polyvinylpyrrolidone K30 and polyethylene glycol dimethyl ether were added simultaneously, the pore size variation coefficient was 36.8% and the wet dynamic friction coefficient was 1.22, indicating that improper addition sequence of pore-forming agents will weaken the division of labor between pore wall template and open-pore migration.

[0092] Compared with the comparative examples above, Examples 1-5 all introduced dihydroxy chain extender monomers with sulfobetaine side groups during the polyurethane chain extension stage, grafted hydroxyalkyl-terminated polydimethylsiloxane in the presence of residual isocyanate groups, and made polyvinylpyrrolidone K30 and polyethylene glycol dimethyl ether act as slow diffusion pore wall templates and fast diffusion opening pore components, respectively. The resulting surface layer has an average pore size of 2.14-3.74 μm, a pore size variation coefficient of 17.8%-25.6%, and an opening porosity of 51.8%-67.5%, which can quickly disperse artificial sweat without excessive water absorption and lubrication.

[0093] The wet dynamic friction coefficients of Examples 3 and 4 reached 1.66 and 1.60, respectively. The wet dynamic friction retention rates after cleaning reached 95.6% and 96.2%, respectively, and the wet dynamic friction retention rates after wear resistance reached 92.8% and 94.6%, respectively. This indicates that the hydrophilic pore wall sites, confined polydimethylsiloxane microregions, and stepwise pore structure are not simply superimposed, but rather have a synergistic effect in terms of sweat adsorption and dispersion, continuous liquid film severing, and pore structure retention after wear.

[0094] In summary, the polyurethane yoga mat surface resin with a microporous structure obtained by this invention has a high wet dynamic friction coefficient, a fast artificial sweat dispersion speed, a high washability / wear resistance retention rate, and good surface-to-substrate peel stability, which can effectively solve the problems of decreased anti-slip performance and insufficient durability of yoga mat surface in sweaty environments.

[0095] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A high-slip polyurethane yoga mat surface resin with a microporous structure, characterized in that, It is a polyurethane surface resin layer applied to the surface of a thermoplastic elastomer yoga mat substrate; the polyurethane surface resin layer is formed by solidifying polyurethane surface resin slurry to form pores. The raw materials for preparing the polyurethane surface resin slurry, excluding the solvent, include, by weight: 180-220 parts polycarbonate diol, 62-72 parts isophorone diisocyanate, 10-20 parts dihydroxy chain extender monomer with sulfobetaine side group, 8-15 parts hydroxyalkyl-terminated polydimethylsiloxane, 18-30 parts polyvinylpyrrolidone K30, 9-14 parts 1,4-butanediol and 6-14 parts polyethylene glycol dimethyl ether.

2. The high-slip polyurethane yoga mat surface resin with a microporous structure according to claim 1, characterized in that, In addition to the solvent, the raw materials used to prepare the polyurethane surface resin slurry also include 0.6-1.4 parts of an organic bismuth catalyst.

3. The high-slip polyurethane yoga mat surface resin with microporous structure according to claim 1, characterized in that, The dihydroxy chain extender monomer with sulfobetaine side groups is attached to the polyurethane chain segment through its hydroxyl groups participating in the chain extension reaction of the isocyanate-terminated polyurethane prepolymer, and the hydroxyalkyl-terminated polydimethylsiloxane is grafted onto the polyurethane chain segment through its hydroxyl groups reacting with the residual isocyanate groups.

4. The high-slip polyurethane yoga mat surface resin with a microporous structure according to claim 1, characterized in that, The dihydroxy chain extender monomer with sulfobetaine side group is obtained by reacting N-methyldiethanolamine and 1,3-propanesulfonyl lactone; the mass ratio of N-methyldiethanolamine to 1,3-propanesulfonyl lactone is 45-55:46-56.

5. The high-slip polyurethane yoga mat surface resin with a microporous structure according to claim 1, characterized in that, The polycarbonate diol has a number-average molecular weight of 1800-2200 and a hydroxyl value of 50-60 mgKOH / g; the hydroxyalkyl-terminated polydimethylsiloxane has a number-average molecular weight of 800-1200; and the polyethylene glycol dimethyl ether has a number-average molecular weight of 400-600.

6. The high-slip polyurethane yoga mat surface resin with a microporous structure according to claim 1, characterized in that, The thickness of the thermoplastic elastomer yoga mat substrate is 3-5 mm, and the surface dyne value of the thermoplastic elastomer yoga mat substrate is not less than 40 mN / m.

7. The high-slip polyurethane yoga mat surface resin with a microporous structure according to claim 1, characterized in that, The polyurethane surface resin layer is formed by coating the polyurethane surface resin slurry with a wet film thickness of 150-210 μm, followed by coagulation, washing, extraction, and drying.

8. The high-slip polyurethane yoga mat surface resin with a microporous structure according to claim 1, characterized in that, The average pore size of the polyurethane surface resin layer is 2.14-3.74 μm, the pore size variation coefficient is 17.8%-25.6%, and the open pore porosity is 51.8%-67.5%.

9. The high-slip polyurethane yoga mat surface resin with a microporous structure according to claim 1, characterized in that, The 5s water contact angle of the polyurethane surface resin layer is 61.2-73.8°, the complete dispersion time of artificial sweat is 8.2s to 22.9s, and the wet dynamic friction coefficient is 1.30-1.66.