Wear-resistant and antibacterial TPU leather

Abstract

The invention discloses a wear-resistant and antibacterial TPU leather. The wear-resistant and antibacterial TPU leather is prepared by laminating a surface layer, a foaming layer, and a bottom layer. The surface layer is prepared from the following raw materials, in parts by weight: 90-100 parts of TPU resin, 15-30 parts of potassium titanate whiskers, 3-8 parts of modified bentonite, 1-3 parts of silver ion antibacterial agent, 5-10 parts of silicone lubricant, and 5-10 parts of color masterbatch; the foaming layer is prepared from the following raw materials: 80-100 parts of TPU resin, 1-5 parts of calcium carbonate, 5-10 parts of color masterbatch, and 5-15 parts of AC foaming agent. The prepared leather is resistant to water washing, dry cleaning, heat resistance, and bending resistance, and has excellent wear resistance, antibacterial and flame retardant properties. The leather can be widely used in the production and manufacturing industries of clothing, shoes, handbags, luggage, seats, architectural decoration, and the like.

Description

Technical Field

[0001] The invention relates to the technical field of artificial leather, in particular to wear-resistant and antibacterial TPU leather. Background Art

[0002] Recent advances in synthetic leather technology and improvements in processing techniques have led to the emergence of a wide variety of synthetic leather materials. Currently, PU and PVC synthetic leathers are widely used in the market. However, these materials struggle to meet environmental requirements during production, resulting in significant harm. Thermoplastic polyurethanes (TPUs), a newly emerging elastomer material, have proven to be environmentally friendly and possess unique physical and chemical properties that rival those of other polymer materials. With the development and cost reduction of TPU materials, as well as the gradual realization of their superior performance, the production of synthetic leather using TPU has become a topic of research for those skilled in the art.

[0003] TPU is a new type of environmentally friendly material, known as a green environmentally friendly material, with excellent physical and mechanical properties, such as good elasticity, good wear resistance, strong tear resistance, and low permanent deformation rate. TPU also has a wide operating temperature range, and most products can be used for a long time within the range of -40 to -80°C. It has advantages such as oil resistance, corrosion resistance, UV resistance, and microbial resistance. TPU is also recyclable.

[0004] TPU foam products produced through the foaming process not only retain their original excellent properties but also offer improved processing performance, a longer service life, and enhanced flexibility, thus playing a vital role in polymer foam production. After foaming, TPU materials can be used in artificial leather, shock-absorbing and cushioning materials, thermal insulation materials, sound insulation materials, coating materials, and more.

[0005] Chinese patent document CN201510068609.7 discloses a TPU physical foaming synthetic leather and its production process and application. The TPU physical foaming leather comprises a surface layer A, a foaming layer B, and a base fabric layer C, which are compounded together from top to bottom. The surface layer A is a film prepared by extrusion casting equipment after TPU particles, lubricant, and masterbatch are mixed and dried in proportion. The foaming layer B is a TPU foam layer produced by extrusion casting equipment equipped with a direction-finding air intake system, which combines a casting production process with physical foaming (gas microporous foaming) technology. The base fabric layer C can be a non-woven fabric, a woven polyester fabric, a nylon fabric, or a microfiber base fabric layer depending on the application. Although the TPU physical foaming synthetic leather obtained by this invention has high mechanical strength, it has deficiencies in wear resistance, antibacterial properties, and flame retardancy. Summary of the Invention

[0006] In order to address the shortcomings of the existing technology, the purpose of the present invention is to provide a wear-resistant and antibacterial TPU leather. The leather is resistant to water washing, dry cleaning, heat resistance, and bending resistance, and has excellent wear resistance, antibacterial and flame retardant properties. It can be widely used in clothing, shoes, handbags, luggage, seats, architectural decoration and other manufacturing industries.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] Disclosed is a wear-resistant and antibacterial TPU leather, which is prepared by laminating a surface layer, a foaming layer, and a bottom layer. The surface layer is prepared from the following raw materials, in parts by weight: 90-100 parts of TPU resin, 15-30 parts of potassium titanate whiskers, 3-8 parts of modified bentonite, 1-3 parts of silver ion antibacterial agent, 5-10 parts of silicone lubricant, and 5-10 parts of color masterbatch; and the foaming layer is prepared from the following raw materials: 80-100 parts of TPU resin, 1-5 parts of calcium carbonate, 5-10 parts of color masterbatch, and 5-15 parts of AC foaming agent.

[0009] Preferably, the preparation method of the modified bentonite comprises the following steps:

[0010] (1) Dissolve N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide in DMF, add triethylamine and stir evenly, add allyl chloride dropwise while stirring, then keep warm and stir to react, remove unreacted products by rotary evaporation, and obtain an intermediate; the specific reaction process is as follows:

[0011]

[0012] (2) DOPO was added to tetrahydrofuran and stirred to dissolve, and then the intermediate and azobisisobutyronitrile were added, and N2 was continuously introduced. The mixture was sealed and stirred for reaction, and the product was distilled under reduced pressure to obtain a modifier. The specific reaction process is as follows:

[0013]

[0014] (3) calcining the bentonite, cooling it to room temperature, grinding and sieving it, adding it to a sulfuric acid solution, stirring it, filtering it, washing it, and drying it to obtain pretreated bentonite;

[0015] (4) Add the pretreated bentonite to the modifier, heat and stir, filter, wash and dry the product to obtain modified bentonite.

[0016] Preferably, in step (1), the allyl chloride is added dropwise over 1.5 to 3 hours, and the reaction is stirred and reacted at 300 to 450 r / min and 25 to 40° C. for 3 to 5 hours.

[0017] Preferably, in step (1), the weight ratio of N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide, triethylamine, allyl chloride and DMF is 21.1:4-6:8.4-10:80-100.

[0018] Preferably, in step (2), the weight ratio of DOPO, intermediate, azobisisobutyronitrile, and tetrahydrofuran is 20-22:25.1:1.6-2.4:100.

[0019] Preferably, in step (2), the stirring reaction condition is 50-65° C. for 8-12 h.

[0020] Preferably, in step (3), the calcination conditions are 200-300°C for 2-4 hours, sieved through an 800-1000 mesh sieve, the concentration of the sulfuric acid solution is 10-20wt%, and the stirring conditions are 80-90°C for 2-4 hours; the weight ratio of bentonite to sulfuric acid solution is 10:40-60.

[0021] Preferably, in step (4), the weight ratio of the pretreated bentonite to the modifier is 10:20-40; and the heating and stirring conditions are 50-65° C. and stirring for 2-3 hours.

[0022] The present invention also claims a method for preparing the wear-resistant and antibacterial leather, comprising the following steps:

[0023] A. Put the raw materials of the skin layer into a high-speed mixer and mix them evenly at a stirring temperature of 100-120°C. Add the stirred materials into a casting machine to cast a film to obtain the skin layer;

[0024] B. Immerse the base fabric in a 10-40 wt% aqueous polyurethane solution for 10-30 min, take it out and dry it at 80-100° C. for 1-5 h to obtain a base layer;

[0025] C. Mix the raw materials of the foaming layer evenly and put them into the extruder, add AC foaming agent, foam through the die, the foaming temperature is 160-260°C, the foaming time is 100-300s, and extrusion casting is performed to obtain the foaming layer;

[0026] D. Transport the epidermis layer, foaming layer and bottom layer to a laminating machine, and perform hot pressing lamination on them in the order of epidermis layer, foaming layer and bottom layer from top to bottom at 130-150°C. The hot pressing temperature is 110-140°C and the laminating time is 10-60s. After embossing, wear-resistant and antibacterial TPU leather is obtained.

[0027] Preferably, in step B, the base fabric is one of woven fabric, knitted fabric or microfiber non-woven fabric; in step C, the AC foaming agent has a fineness of 5 to 8 μm, a gas emission of 200 to 220 mL / g, and a decomposition temperature of 180 to 220°C.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1) The present invention provides a wear-resistant and antibacterial TPU leather, which is made by laminating an epidermis, a foaming layer, and a bottom layer. By adding potassium titanate whiskers, a silver ion antibacterial agent, and modified bentonite, the leather is given excellent wear resistance, antibacterial, and flame retardant properties; potassium titanate whiskers have good rigidity, stability, thermal stability, and strength, can increase the tensile strength and wear resistance of the TPU material, and can effectively improve the wear resistance and flame retardancy of the leather by synergizing with modified bentonite. The leather can be widely used in the production and manufacturing industries such as clothing, shoes, handbags, luggage, seats, and architectural decoration.

[0030] 2) The present invention provides a modified bentonite, which first uses triethylamine as an acid-binding agent to generate an intermediate having a propenyl ether structure through a substitution reaction between N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide and allyl chloride, and then uses azobisisobutyronitrile as an initiator to react the PH bond in DOPO with the double bond of the intermediate, and grafts DOPO onto the intermediate to obtain a modifier. Finally, the bentonite is calcined and acidified, and modified with the modifier to prepare the modified bentonite. Bentonite is a silicate mineral rich in magnesium and aluminum. The modified bentonite prepared by the present invention It has the advantages of phosphorus flame retardants, nitrogen flame retardants and silicon flame retardants. The modified bentonite can be pyrolyzed at high temperature to produce polyphosphoric acid or metaphosphoric acid derivatives to accelerate the formation of the carbon layer, and can also release inert gases such as NH3 to dilute the concentration of combustible gases. At the same time, the formation of silicon layer and carbon layer can also effectively isolate oxygen and heat. DOPO, N-hydroxymethyl-3-(dimethyloxyphosphinoyl) propionamide and bentonite can synergistically exert excellent flame retardant effects, and the modifier can organically modify the bentonite so that it can be better dispersed in the TPU matrix, which can effectively improve the mechanical properties of leather. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0032] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from commercially purchased raw materials.

[0033] The TPU resin has a Shore hardness of 75-80A and is purchased from Huafeng Thermoplastic Polyurethane Co., Ltd.

[0034] Silver ion antimicrobial agent was purchased from Kangye Biotechnology (Dongguan) Co., Ltd.;

[0035] Calcium carbonate was purchased from Hebei Hongze New Material Technology Co., Ltd. with a particle size of 800-1000 mesh.

[0036] The present invention will be further described below with reference to specific examples.

[0037] Example 1

[0038] A method for preparing wear-resistant and antibacterial TPU leather comprises the following steps:

[0039] (1) Dissolve 21.1 g of N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide in 100 g of DMF, add 6 g of triethylamine and stir evenly, then add 10 g of allyl chloride dropwise under stirring for 3 h, then stir at 450 rpm and 40°C for 5 h, and remove unreacted materials by rotary evaporation to obtain an intermediate;

[0040] (2) 22 g of DOPO was added to 100 g of tetrahydrofuran and stirred to dissolve. Then, 25.1 g of the intermediate and 2.4 g of azobisisobutyronitrile were added. N2 was continuously introduced. The mixture was sealed and stirred at 65°C for 12 h. The product was distilled under reduced pressure to obtain a modifier.

[0041] (3) 10 g of bentonite was calcined at 300° C. for 4 h, cooled to room temperature after calcination, ground through a 1000 mesh sieve, added to 60 g of a 20 wt % sulfuric acid solution, stirred at 90° C. for 4 h, filtered, washed, and dried to obtain pretreated bentonite;

[0042] (4) Add 10 g of pretreated bentonite to 40 g of the modifier, stir at 65 °C for 3 h, filter, wash, and dry the product to obtain modified bentonite;

[0043] (5) 95 g of TPU resin, 20 g of potassium titanate whiskers, 8 g of modified bentonite, 2 g of silver ion antibacterial agent, 8 g of silicone lubricant, and 7 g of brown masterbatch were put into a high-speed blender and mixed uniformly at a stirring temperature of 110° C. The stirred materials were added to a casting machine and cast into a film to obtain a skin layer;

[0044] (6) Immersing the base fabric in a 20 wt% aqueous polyurethane solution for 20 min, taking it out and drying it at 90° C. for 3 h to obtain a base layer;

[0045] (7) 90 g of TPU resin, 3 g of calcium carbonate, and 7 g of brown masterbatch were mixed evenly and put into an extruder. 10 g of AC foaming agent was added and foamed through a die at a foaming temperature of 200 ° C and a foaming time of 200 s. The mixture was extruded and cast to obtain a foamed layer.

[0046] (8) The epidermis layer, the foaming layer and the bottom layer are transported to a laminating machine and hot pressed and laminated in the order of the epidermis layer, the foaming layer and the bottom layer from top to bottom at 140°C. The hot pressing temperature is 120°C and the laminating time is 40s. After embossing, wear-resistant and antibacterial TPU leather is obtained.

[0047] Example 2

[0048] A method for preparing wear-resistant and antibacterial TPU leather comprises the following steps:

[0049] (1) Dissolve 21.1 g of N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide in 80 g of DMF, add 4 g of triethylamine and stir evenly, then add 8.4 g of allyl chloride dropwise under stirring for 1.5 h, then stir and react at 300 rpm and 25°C for 3 h, and remove unreacted materials by rotary evaporation to obtain an intermediate;

[0050] (2) 20 g of DOPO was added to 100 g of tetrahydrofuran and stirred to dissolve. Then, 25.1 g of the intermediate and 1.6 g of azobisisobutyronitrile were added. N2 was continuously introduced. The mixture was sealed and stirred at 50°C for 8 h. The product was distilled under reduced pressure to obtain a modifier.

[0051] (3) 10 g of bentonite was calcined at 200° C. for 2 h, cooled to room temperature after calcination, ground through an 800-mesh sieve, added to a 40.15 wt % sulfuric acid solution, stirred at 80° C. for 2 h, filtered, washed, and dried to obtain pretreated bentonite;

[0052] (4) Add 10 g of pretreated bentonite to 20 g of the modifier, stir at 50 °C for 2 h, filter, wash, and dry the product to obtain modified bentonite;

[0053] (5) 95 g of TPU resin, 20 g of potassium titanate whiskers, 3 g of modified bentonite, 2 g of silver ion antibacterial agent, 8 g of silicone lubricant, and 7 g of brown masterbatch were put into a high-speed blender and mixed uniformly at a stirring temperature of 110° C. The stirred materials were added to a casting machine and cast into a film to obtain a skin layer;

[0054] (6) Immersing the base fabric in a 20 wt% aqueous polyurethane solution for 20 min, taking it out and drying it at 90° C. for 3 h to obtain a base layer;

[0055] (7) 90 g of TPU resin, 3 g of calcium carbonate, and 7 g of brown masterbatch were mixed evenly and put into an extruder. 10 g of AC foaming agent was added and foamed through a die at a foaming temperature of 200 ° C and a foaming time of 200 s. The mixture was extruded and cast to obtain a foamed layer.

[0056] (8) The epidermis layer, the foaming layer and the bottom layer are transported to a laminating machine and hot pressed and laminated in the order of the epidermis layer, the foaming layer and the bottom layer from top to bottom at 140°C. The hot pressing temperature is 120°C and the laminating time is 40s. After embossing, wear-resistant and antibacterial TPU leather is obtained.

[0057] Example 3

[0058] A method for preparing wear-resistant and antibacterial TPU leather comprises the following steps:

[0059] (1) Dissolve 21.1 g of N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide in 90 g of DMF, add 5 g of triethylamine and stir evenly, then add 9.2 g of allyl chloride dropwise under stirring for 2 h, then stir and react at 400 rpm and 30°C for 4 h, remove unreacted materials by rotary evaporation to obtain an intermediate;

[0060] (2) 21 g of DOPO was added to 100 g of tetrahydrofuran and stirred to dissolve. Then, 25.1 g of the intermediate and 2.0 g of azobisisobutyronitrile were added. N2 was continuously introduced. The mixture was sealed and stirred at 60°C for 10 h. The product was distilled under reduced pressure to obtain a modifier.

[0061] (3) 10 g of bentonite was calcined at 250° C. for 3 h, cooled to room temperature after calcination, ground through an 800-mesh sieve, added to 50 g of a 15 wt% sulfuric acid solution, stirred at 85° C. for 3 h, filtered, washed, and dried to obtain pretreated bentonite;

[0062] (4) Add 10 g of pretreated bentonite to 30 g of the modifier, stir at 60 °C for 2.5 h, filter, wash, and dry the product to obtain modified bentonite;

[0063] (5) 95 g of TPU resin, 20 g of potassium titanate whiskers, 6 g of modified bentonite, 2 g of silver ion antibacterial agent, 8 g of silicone lubricant, and 7 g of brown masterbatch were put into a high-speed blender and mixed uniformly at a stirring temperature of 110° C. The stirred materials were added to a casting machine and cast into a film to obtain a skin layer;

[0064] (6) Immersing the base fabric in a 20 wt% aqueous polyurethane solution for 20 min, taking it out and drying it at 90° C. for 3 h to obtain a base layer;

[0065] (7) 90 g of TPU resin, 3 g of calcium carbonate, and 7 g of brown masterbatch were mixed evenly and put into an extruder. 10 g of AC foaming agent was added and foamed through a die at a foaming temperature of 200 ° C and a foaming time of 200 s. The mixture was extruded and cast to obtain a foamed layer.

[0066] (8) The epidermis layer, the foaming layer and the bottom layer are transported to a laminating machine and hot pressed and laminated in the order of the epidermis layer, the foaming layer and the bottom layer from top to bottom at 140°C. The hot pressing temperature is 120°C and the laminating time is 40s. After embossing, wear-resistant and antibacterial TPU leather is obtained.

[0067] Comparative Example 1

[0068] A method for preparing TPU leather comprises the following steps:

[0069] (1) Dissolve 21.1 g of N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide in 100 g of DMF, add 6 g of triethylamine and stir evenly, then add 10 g of allyl chloride dropwise under stirring for 3 h, then stir at 450 rpm and 40°C for 5 h, and remove unreacted materials by rotary evaporation to obtain an intermediate;

[0070] (2) 10 g of bentonite was calcined at 300° C. for 4 h, cooled to room temperature after calcination, ground through a 1000 mesh sieve, added to 60 g of a 20 wt % sulfuric acid solution, stirred at 90° C. for 4 h, filtered, washed, and dried to obtain pretreated bentonite;

[0071] (3) Add 10 g of pretreated bentonite to 40 g of the intermediate, stir at 65 °C for 3 h, filter, wash, and dry the product to obtain modified bentonite;

[0072] (4) 95 g of TPU resin, 20 g of potassium titanate whiskers, 8 g of modified bentonite, 2 g of silver ion antibacterial agent, 8 g of silicone lubricant, and 7 g of brown masterbatch were put into a high-speed blender and mixed uniformly at a stirring temperature of 110° C. The stirred materials were added to a casting machine and cast into a film to obtain a skin layer;

[0073] (5) Immersing the base fabric in a 20 wt% aqueous polyurethane solution for 20 min, taking it out and drying it at 90° C. for 3 h to obtain a base layer;

[0074] (6) 90 g of TPU resin, 3 g of calcium carbonate, and 7 g of brown masterbatch were mixed evenly and put into an extruder. 10 g of AC foaming agent was added and foamed through a die at a foaming temperature of 200 ° C and a foaming time of 200 s. The mixture was extruded and cast to obtain a foamed layer.

[0075] (7) The epidermis layer, the foaming layer, and the bottom layer are transported to a laminating machine and hot-pressed and laminated in the order of the epidermis layer, the foaming layer, and the bottom layer from top to bottom at 140°C. The hot-pressing temperature is 120°C, and the laminating time is 40s. After embossing, wear-resistant and antibacterial TPU leather is obtained.

[0076] Comparative Example 2

[0077] A method for preparing TPU leather comprises the following steps:

[0078] (1) 10 g of bentonite was calcined at 300° C. for 4 h, cooled to room temperature after calcination, ground through a 1000 mesh sieve, added to 60 g of a 20 wt % sulfuric acid solution, stirred at 90° C. for 4 h, filtered, washed, and dried to obtain pretreated bentonite;

[0079] (2) 95 g of TPU resin, 20 g of potassium titanate whiskers, 8 g of pretreated bentonite, 2 g of silver ion antibacterial agent, 8 g of silicone lubricant, and 7 g of brown masterbatch were mixed uniformly in a high-speed mixer at a stirring temperature of 110° C. The stirred materials were added to a casting machine and cast into a film to obtain a skin layer;

[0080] (3) Immersing the base fabric in a 20 wt% aqueous polyurethane solution for 20 min, taking it out and drying it at 90° C. for 3 h to obtain a base layer;

[0081] (4) 90 g of TPU resin, 3 g of calcium carbonate, and 7 g of brown masterbatch were mixed evenly and put into an extruder. 10 g of AC foaming agent was added and foamed through a die at a foaming temperature of 200 ° C and a foaming time of 200 s. The mixture was extruded and cast to obtain a foamed layer.

[0082] (5) The epidermis layer, the foaming layer and the bottom layer are transported to a laminating machine and hot pressed and laminated in the order of the epidermis layer, the foaming layer and the bottom layer from top to bottom at 140°C. The hot pressing temperature is 120°C and the laminating time is 40s. After embossing, wear-resistant and antibacterial TPU leather is obtained.

[0083] Comparative Example 3

[0084] A method for preparing wear-resistant and antibacterial TPU leather comprises the following steps:

[0085] (1) Dissolve 21.1 g of N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide in 100 g of DMF, add 6 g of triethylamine and stir evenly, then add 10 g of allyl chloride dropwise under stirring for 3 h, then stir at 450 rpm and 40°C for 5 h, and remove unreacted materials by rotary evaporation to obtain an intermediate;

[0086] (2) 22 g of DOPO was added to 100 g of tetrahydrofuran and stirred to dissolve. Then, 25.1 g of the intermediate and 2.4 g of azobisisobutyronitrile were added. N2 was continuously introduced. The mixture was sealed and stirred at 65°C for 12 h. The product was distilled under reduced pressure to obtain a modifier.

[0087] (3) 10 g of bentonite was calcined at 300° C. for 4 h, cooled to room temperature after calcination, ground through a 1000 mesh sieve, added to 60 g of a 20 wt % sulfuric acid solution, stirred at 90° C. for 4 h, filtered, washed, and dried to obtain pretreated bentonite;

[0088] (4) Add 10 g of pretreated bentonite to 40 g of the modifier, stir at 65 °C for 3 h, filter, wash, and dry the product to obtain modified bentonite;

[0089] (5) 95 g of TPU resin, 8 g of modified bentonite, 2 g of silver ion antibacterial agent, 8 g of silicone lubricant, and 7 g of brown masterbatch were put into a high-speed mixer and mixed evenly at a stirring temperature of 110° C. The stirred materials were added to a casting machine and cast into a film to obtain a skin layer;

[0090] (6) Immersing the base fabric in a 20 wt% aqueous polyurethane solution for 20 min, taking it out and drying it at 90° C. for 3 h to obtain a base layer;

[0091] (7) 90 g of TPU resin, 3 g of calcium carbonate, and 7 g of brown masterbatch were mixed evenly and put into an extruder. 10 g of AC foaming agent was added and foamed through a die at a foaming temperature of 200 ° C and a foaming time of 200 s. The mixture was extruded and cast to obtain a foamed layer.

[0092] (8) The epidermis layer, the foaming layer and the bottom layer are transported to a laminating machine and hot pressed and laminated in the order of the epidermis layer, the foaming layer and the bottom layer from top to bottom at 140°C. The hot pressing temperature is 120°C and the laminating time is 40s. After embossing, wear-resistant and antibacterial TPU leather is obtained.

[0093] Comparative Example 4

[0094] A method for preparing wear-resistant and antibacterial TPU leather comprises the following steps:

[0095] (1) Dissolve 21.1 g of N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide in 100 g of DMF, add 6 g of triethylamine and stir evenly, then add 10 g of allyl chloride dropwise under stirring for 3 h, then stir at 450 rpm and 40°C for 5 h, and remove unreacted materials by rotary evaporation to obtain an intermediate;

[0096] (2) 22 g of DOPO was added to 100 g of tetrahydrofuran and stirred to dissolve. Then, 25.1 g of the intermediate and 2.4 g of azobisisobutyronitrile were added. N2 was continuously introduced. The mixture was sealed and stirred at 65°C for 12 h. The product was distilled under reduced pressure to obtain a modifier.

[0097] (3) 10 g of bentonite was calcined at 300° C. for 4 h, cooled to room temperature after calcination, ground through a 1000 mesh sieve, added to 60 g of a 20 wt % sulfuric acid solution, stirred at 90° C. for 4 h, filtered, washed, and dried to obtain pretreated bentonite;

[0098] (4) Add 10 g of pretreated bentonite to 40 g of the modifier, stir at 65 °C for 3 h, filter, wash, and dry the product to obtain modified bentonite;

[0099] (5) 95 g of TPU resin, 20 g of potassium titanate whiskers, 8 g of modified bentonite, 8 g of silicone lubricant, and 7 g of brown masterbatch were mixed uniformly in a high-speed mixer at a stirring temperature of 110° C. The stirred materials were added to a casting machine and cast into a film to obtain a skin layer;

[0100] (6) Immersing the base fabric in a 20 wt% aqueous polyurethane solution for 20 min, taking it out and drying it at 90° C. for 3 h to obtain a base layer;

[0101] (7) 90 g of TPU resin, 3 g of calcium carbonate, and 7 g of brown masterbatch were mixed evenly and put into an extruder. 10 g of AC foaming agent was added and foamed through a die at a foaming temperature of 200 ° C and a foaming time of 200 s. The mixture was extruded and cast to obtain a foamed layer.

[0102] (8) The epidermis layer, the foaming layer and the bottom layer are transported to a laminating machine and hot pressed and laminated in the order of the epidermis layer, the foaming layer and the bottom layer from top to bottom at 140°C. The hot pressing temperature is 120°C and the laminating time is 40s. After embossing, wear-resistant and antibacterial TPU leather is obtained.

[0103] The leathers prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were subjected to performance tests. The tensile strength was detected with reference to QB / T 1646-2007 “Polyurethane Synthetic Leather”, the tear strength was detected with reference to QB / T 2710-2018 “Leather Physical and Mechanical Tests - Determination of Tensile Strength and Elongation”, the wear resistance was detected by using the Martindale test method with reference to QB / T 2726-2005 “Leather Physical and Mechanical Tests - Determination of Abrasion Resistance”, the folding resistance at room temperature was detected with reference to QB / T 2714-2018 “Leather Physical and Mechanical Tests - Determination of Folding Fastness”, the hydrolysis resistance was detected by using a 10% sodium hydroxide test for 48 hours with reference to QB / T 4671-2014 “Test Methods for Artificial Leather and Synthetic Leather - Determination of Hydrolysis Resistance”, and the limiting oxygen index was detected with reference to GB / T 2406.2-2009 “Plastics - Determination of Burning Behavior by Oxygen Index Method - Part 2: Room Temperature Test”. The specific data are shown in Table 1.

[0104] Table 1 TPU leather performance test results

[0105]

[0106] In Comparative Example 3, potassium titanate whiskers were not added, and the mechanical properties of the leather prepared were worse than those in Example. In Comparative Example 2, the bentonite was not modified with a modifier, and the dispersion of the bentonite in the TPU matrix was poor, which had a certain negative impact on the mechanical properties of the leather. In Comparative Example 1, DOPO was not grafted, and the flame retardant properties were somewhat lower than those in Example. In Comparative Example 2, the bentonite was not modified with a modifier, and the flame retardant properties were poor.

[0107] The antibacterial performance of the leather prepared in Examples 1 to 3 and Comparative Example 4 was tested. Staphylococcus aureus and Escherichia coli were activated and amplified, and then diluted to a concentration of 5×10 5 A bacterial suspension of 1.5 CFU / mL was prepared, and 200 μL of the bacterial suspension was taken out with a sterile pipette and evenly spread on the surface of each sample. The samples were incubated at 37°C for 24 h. The bacteria on the sample surface were then washed off with an equal volume of culture medium, and the samples were incubated at 37°C for another 8 h. After dilution, the samples were plated and the number of colonies in each group of samples was counted (each sample was repeated 3 times in parallel and the average value was taken). The results are shown in Table 2.

[0108] Table 2 Leather antibacterial rate test results (CFU / mL)

[0109]

[0110] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A wear-resistant and antibacterial TPU leather, made by laminating an epidermis layer, a foaming layer, and a bottom layer, characterized in that: The skin layer is made of the following raw materials, in parts by weight: 90-100 parts of TPU resin, 15-30 parts of potassium titanate whiskers, 3-8 parts of modified bentonite, 1-3 parts of silver ion antibacterial agent, 5-10 parts of silicone lubricant, and 5-10 parts of color masterbatch; the foaming layer is made of the following raw materials: 80-100 parts of TPU resin, 1-5 parts of calcium carbonate, 5-10 parts of color masterbatch, and 5-15 parts of AC foaming agent; The preparation method of the modified bentonite comprises the following steps: (1) Dissolve N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide in DMF, add triethylamine and stir evenly, add allyl chloride dropwise while stirring, then keep warm and stir to react, remove unreacted products by rotary evaporation to obtain an intermediate; (2) Add DOPO to tetrahydrofuran, stir and dissolve, then add the intermediate and azobisisobutyronitrile, continue to introduce N2, seal and stir to react, and distill the product under reduced pressure to obtain the modifier; (3) After calcining the bentonite, cooling it to room temperature, grinding and sieving it, adding it to a sulfuric acid solution and stirring it, filtering, washing, and drying it to obtain pretreated bentonite; (4) Add the pretreated bentonite to the modifier, heat and stir, filter, wash and dry the product to obtain modified bentonite.

2. The wear-resistant and antibacterial TPU leather according to claim 1, characterized in that: In step (1), allyl chloride is added dropwise over a period of 1.5 to 3 hours, and the reaction is stirred at 300 to 450 r / min and 25 to 40° C. for 3 to 5 hours.

3. The wear-resistant and antibacterial TPU leather according to claim 1, characterized in that In step (1), the weight ratio of N-hydroxymethyl-3-(dimethylphosphinoyl)propionamide, triethylamine, allyl chloride and DMF is 21.1:4~6:8.4~10:80~100.

4. The wear-resistant and antibacterial TPU leather according to claim 1, characterized in that In step (2), the weight ratio of DOPO, intermediate, azobisisobutyronitrile, and tetrahydrofuran is 20-22: 25.1：1.6~2.4：100。 5. The wear-resistant and antibacterial TPU leather according to claim 1, characterized in that: In step (2), the stirring reaction conditions are 50-65° C. and the reaction time is 8-12 h.

6. The wear-resistant and antibacterial TPU leather according to claim 1, characterized in that In step (3), the calcination conditions are 200-300°C for 2-4 hours, passing through an 800-1000 mesh sieve, the concentration of the sulfuric acid solution is 10-20wt%, and the stirring conditions are 80-90°C for 2-4 hours; the weight ratio of bentonite to sulfuric acid solution is 10:40-60.

7. The wear-resistant and antibacterial TPU leather according to claim 1, characterized in that: In step (4), the weight ratio of the pretreated bentonite to the modifier is 10:20~40; and the heating and stirring conditions are 50~65°C and stirring for 2~3h.

8. A method for preparing the wear-resistant and antibacterial TPU leather according to any one of claims 1 to 7, characterized in that: The steps include: A. Put the raw materials of the skin layer into a high-speed mixer and mix them evenly at a stirring temperature of 100-120°C. Add the stirred materials into a casting machine to cast a film to obtain the skin layer; B. Immerse the base fabric in a 10-40wt% aqueous polyurethane solution for 10-30 minutes, take it out and dry it at 80-100°C for 1-5 hours to obtain a base layer; C. Mix the raw materials of the foaming layer evenly and put them into the extruder, add AC foaming agent, foam through the die, the foaming temperature is 160~260℃, the foaming time is 100~300s, and extrude and cast to obtain the foaming layer; D. Transport the epidermis layer, foaming layer and bottom layer to the laminating machine, and perform hot pressing lamination from top to bottom in the order of epidermis layer, foaming layer and bottom layer at 130-150°C. The hot pressing temperature is 110-140°C and the laminating time is 10-60s. After embossing, wear-resistant and antibacterial TPU leather is obtained.

9. The preparation method according to claim 8, characterized in that In step B, the base fabric is one of woven fabric, knitted fabric or microfiber non-woven fabric; in step C, the AC foaming agent has a fineness of 5-8 μm, a gas emission of 200-220 mL / g, and a decomposition temperature of 180-220°C.

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