Recyclable TPU non-woven fabric leather and preparation method thereof

Abstract

The invention relates to the technical field of TPU, in particular to recyclable TPU non-woven fabric leather and a preparation method thereof. The recyclable TPU non-woven fabric leather comprises a PU texture layer and a TPU melt-blown fabric layer which are sequentially arranged from top to bottom. The recyclable TPU non-woven fabric leather has the advantages of being antibacterial, breathable, soft, high in adhesive force and high in tensile property. The preparation method of the recyclable TPU non-woven fabric leather is simple in process, easy to control in operation and beneficial to industrial mass production, and the prepared recyclable TPU non-woven fabric leather is stable in quality and excellent in comprehensive performance.

Description

Technical Field

[0001] The invention relates to the technical field of TPU, and in particular to a recyclable TPU non-woven leather and a preparation method thereof. Background Art

[0002] Polyurethane (TPU) is a widely used high-performance material. Due to its excellent wear resistance, tear resistance and elasticity, it is widely used in various products such as clothing, shoes, wall coverings, sofas, car seats, etc.

[0003] In the field of non-woven fabric preparation technology, non-woven fabric is a kind of fabric that does not require spinning and weaving. It has a simple production process, low cost, good air permeability and moisture absorption, and is therefore widely used in various fields. However, due to the poor antibacterial properties and tensile strength of traditional non-woven fabrics, it is difficult to recycle and reuse after use, which puts pressure on the environment. In the field of environmentally friendly material recycling technology, with the improvement of environmental awareness, how to effectively recycle and reuse various materials and reduce environmental pollution is an important research direction at present. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a recyclable TPU non-woven leather, which has the characteristics of antibacterial, breathable and soft, strong adhesion and strong tensile properties.

[0005] The preparation method of the recyclable TPU non-woven leather of the present invention has simple process, easy controllable operation, and is conducive to large-scale industrial production. The prepared recyclable TPU non-woven leather has stable quality, is antibacterial, breathable and soft, has strong adhesion and tensile properties, and has excellent comprehensive performance.

[0006] The purpose of the present invention is achieved through the following technical solution: a recyclable TPU non-woven leather, comprising a PU texture layer and a TPU meltblown fabric layer arranged in sequence from top to bottom.

[0007] In the above technical solution, the thickness of the TPU meltblown cloth layer is 0.3-0.8 cm, and the thickness of the PU texture layer is 0.04-0.08 cm.

[0008] In the above technical solution, the preparation method of the polyurethane coating comprises the following steps:

[0009] B1. Place polyethylene glycol and modified soybean oil polyol under protective gas protection, dehydrate at 105-115° C. for 1-3 hours, cool to 75-85° C., add hexamethylene diisocyanate, dimethylol propionic acid and an organic tin catalyst, and react for 2-3 hours to obtain a polyurethane prepolymer;

[0010] B2. Add sodium bisulfite as a capping agent to the polyurethane prepolymer and continue reacting at 75-85° C. for 2-3 hours to obtain a polyurethane coating.

[0011] In the above technical scheme, the molar ratio of polyethylene glycol, modified soybean oil polyol, dimethylol propionic acid, hexamethylene diisocyanate and sodium bisulfite is 0.6-0.8: 0.2-0.4: 0.8-1.2: 1-3: 0.1-0.3. The amount of the organic tin catalyst added is 0.05-0-.15% of the total mass of polyethylene glycol, modified soybean oil polyol, dimethylol propionic acid and hexamethylene diisocyanate; the amount of the deionizer added is 80-90% of the total mass of polyethylene glycol, modified soybean oil polyol, dimethylol propionic acid and hexamethylene diisocyanate.

[0012] In the above technical scheme, the preparation method of the modified soybean oil polyol comprises the following steps:

[0013] E1. Add a certain amount of 40% by mass fluoroboric acid aqueous solution, acetone and polycaprolactone diol into a reactor and heat to 56° C. Then gradually add soybean oil polyol into the reactor within 10 minutes, control the temperature at 56° C., and react for another 20 minutes to obtain a composite;

[0014] E2. Add dimethylethanolamine to the complex to neutralize the fluoroboric acid to neutrality, and finally extract the acetone and water to obtain the modified soybean oil polyol.

[0015] In the above technical solution, the molar ratio of the polycaprolactone diol to the soybean oil polyol is 3.5-4.2:0.8-1.2, the soybean oil polyol adopts soybean oil polyol with an epoxy value of 6%, and the polycaprolactone diol adopts polycaprolactone diol 1000.

[0016] In the above technical solution, the TPU meltblown cloth layer is made of an electrospinning solution, which includes 100 parts of an organic solvent, 4-10 parts of a foaming agent, 7-12 parts of nanocellulose and 16-20 parts of polyether TPU particles.

[0017] In the above technical solution, the organic solvent is a mixture of THM and DMF in a mass ratio of 1:9.

[0018] In the above technical solution, the method for preparing the electrospinning solution comprises the following steps: dissolving a foaming agent, nanocellulose and polyether TPU particles in an organic solvent and stirring the mixture evenly to obtain an electrospinning solution.

[0019] In the above technical solution, the foaming agent is sodium bicarbonate.

[0020] In the above technical solution, the nanocellulose is extracted from pine needles. The preparation method of the nanocellulose comprises the following steps:

[0021] (1) Wash the pine needles thoroughly with warm water for 4-5 times to remove dirt and water-soluble substances, and then dry them for 24 hours. Cut the cleaned needles into 4-5 mm pieces to obtain pine needle fragments;

[0022] (2) Toluene and ethanol were mixed in a volume ratio of 2:1 to prepare a mixed solvent, 20 g of pine needle fragments were immersed in the mixed solvent for 6 h for extraction to remove wax, pigment and oil, and then dried at 45 ° C for 10 h to obtain pretreated needle A;

[0023] (3) The needles of pretreatment A were immersed in 0.7% NaCl 2 O, adjust the pH to 3.0-4.0 with glacial acetic acid, and dissolve the lignin in the needles at 90°C for 1 hour. Repeat this step twice to obtain pretreated needles B;

[0024] (4) The pretreated needle leaf B was immersed in 5% KOH at 90° C. for 2 h, filtered and washed, and then extracted with 10% KOH at 90° C. for 2 h. Finally, it was washed with a large amount of water until the filtrate reached neutrality, thereby obtaining the pretreated needle leaf C;

[0025] (5) hydrolyzing the pretreated needle leaf C with 60% by mass sulfuric acid at 45° C. until dissolved, and terminating the acid hydrolysis process by diluting it with 10 times ice water to obtain a nanocellulose mixed solution;

[0026] (6) washing the obtained nanocellulose mixed solution with deionized water and centrifuging at 8000 rpm for 10 minutes, then repeating the centrifugation 3 to 5 times, and dialyzing the solution for about 3-4 days until it is neutral;

[0027] (7) using a cell disruptor to ultrasonically treat the nanocellulose mixed solution at 600 W to obtain a stable nanocellulose suspension;

[0028] (8) The nanocellulose suspension is placed in an oven at 80° C. and heated to constant weight to obtain nanocellulose.

[0029] In the above technical solution, an electrospinning device is used to electrospin the electrospinning solution to prepare a TPU melt-blown fabric layer, and the specific steps are as follows:

[0030] D1. Take the base fabric and wrap it on the drum for receiving, load the electrospinning solution into the syringe, and set the distance between the drum and the needle tip to 18-20cm;

[0031] D2. Setting the electrospinning parameters, applying a voltage of 15-20 kV, and a solution feed rate of 1-1.5 mL / h, electrospinning the prepared electrospinning solution onto the surface of the base fabric to obtain a TPU meltblown fabric semi-finished product;

[0032] D3. Remove the prepared TPU meltblown fabric layer semi-finished product from the base fabric and dry it in a vacuum oven at 60-75°C for 5-6 hours to ensure that all the solvent is volatilized to obtain the TPU meltblown fabric layer.

[0033] The present invention also provides a method for preparing a recyclable TPU non-woven leather, comprising the following steps:

[0034] (1) At room temperature, a polyurethane coating is applied to the upper surface of the TPU meltblown fabric layer to form a PU coating;

[0035] (2) The PU coating is hot-pressed at 95-115° C. using an embossing roller to form an uneven texture structure on the upper surface of the PU coating, thereby obtaining a PU texture layer.

[0036] The beneficial effects of the present invention are as follows: the recyclable TPU non-woven leather of the present invention has the characteristics of antibacterial, breathable and soft, strong adhesion and strong tensile performance, and has a simple structure and is easy to use.

[0037] At the same time, the preparation method of the recyclable TPU non-woven leather has a simple process and is easy to control, which is conducive to large-scale industrial production. The obtained recyclable TPU non-woven leather has stable quality, is antibacterial, breathable and soft, has strong adhesion and tensile properties, and has excellent comprehensive performance. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0039] Example 1

[0040] In this embodiment, a recyclable TPU non-woven leather includes a PU texture layer and a TPU meltblown fabric layer arranged in sequence from top to bottom.

[0041] Furthermore, the thickness of the TPU meltblown fabric layer is 0.5 cm, and the thickness of the PU texture layer is 0.05 cm.

[0042] Furthermore, the preparation method of the polyurethane coating comprises the following steps:

[0043] B1. Place polyethylene glycol and modified soybean oil polyol under protective gas protection, dehydrate at 110° C. for 2 h, cool to 80° C., add hexamethylene diisocyanate, dimethylol propionic acid and an organic tin catalyst, and react for 2.5 h to obtain a polyurethane prepolymer;

[0044] B2. Add sodium bisulfite as a capping agent to the polyurethane prepolymer and continue the reaction at 80° C. for 1.5 hours to obtain a polyurethane prepolymer.

[0045] Furthermore, the molar ratio of the polyethylene glycol, modified soybean oil polyol, dimethylol propionic acid, hexamethylene diisocyanate and sodium bisulfite is 0.7:0.3:1:1.5:0.2. The amount of the organic tin catalyst added is 0.08% of the total amount of the polyethylene glycol, modified soybean oil polyol, dimethylol propionic acid and hexamethylene diisocyanate; the amount of the deionizer added is 85% of the total amount of the polyethylene glycol, modified soybean oil polyol, dimethylol propionic acid and hexamethylene diisocyanate.

[0046] In this embodiment, the polyethylene glycol is polyethylene glycol 1500.

[0047] Furthermore, the preparation method of the modified soybean oil polyol comprises the following steps:

[0048] E1. Add a certain amount of 40% by mass fluoroboric acid aqueous solution, acetone and polycaprolactone diol into a reactor and heat to 56° C. Then gradually add soybean oil polyol into the reactor within 10 minutes, control the temperature at 56° C., and react for another 20 minutes to obtain a composite;

[0049] E2. Add dimethylethanolamine to the complex to neutralize the fluoroboric acid to neutrality, and finally extract the acetone and water to obtain the modified soybean oil polyol.

[0050] Furthermore, the molar ratio of the polycaprolactone diol to the soybean oil polyol is 3.75:1, the soybean oil polyol uses a soybean oil polyol with an epoxy value of 6%, and the polycaprolactone diol uses polycaprolactone diol 1000.

[0051] Furthermore, the TPU meltblown fabric layer is made of an electrospinning solution, which includes 100 parts of an organic solvent, 4 parts of a foaming agent, 7 parts of nanocellulose and 16 parts of polyether TPU particles.

[0052] Furthermore, the organic solvent is a mixture of THM and DMF in a mass ratio of 1:9.

[0053] In this embodiment, the polyether TPU particles are polyether TPU particles with a brand number of 58237 from Lubrizol, USA.

[0054] Furthermore, the foaming agent is sodium bicarbonate.

[0055] Furthermore, the preparation method of the electrospinning solution comprises the following steps: dissolving a foaming agent, nanocellulose and polyether TPU particles in an organic solvent and stirring the mixture evenly to obtain an electrospinning solution.

[0056] Furthermore, the nanocellulose is extracted from pine needles. The preparation method of the nanocellulose comprises the following steps:

[0057] (1) Wash the pine needles thoroughly with warm water for 4-5 times to remove dirt and water-soluble substances, and then dry them for 24 hours. Cut the cleaned needles into 4-5 mm pieces to obtain pine needle fragments;

[0058] (2) Toluene and ethanol were mixed in a volume ratio of 2:1 to prepare a mixed solvent, 20 g of pine needle fragments were immersed in the mixed solvent for 6 h for extraction to remove wax, pigment and oil, and then dried at 45 ° C for 10 h to obtain pretreated needle A;

[0059] (3) The needles of pretreatment A were immersed in 0.7% NaCl 2 O, the pH was adjusted to 3.5 with glacial acetic acid, and the lignin in the needles was dissolved at 90°C for 1 hour. This step was repeated twice to obtain pretreated needles B;

[0060] (4) The pretreated needle leaf B was immersed in 5% KOH at 90° C. for 2 h, filtered and washed, and then extracted with 10% KOH at 90° C. for 2 h. Finally, it was washed with a large amount of water until the filtrate reached neutrality, thereby obtaining the pretreated needle leaf C;

[0061] (5) hydrolyzing the pretreated needle leaf C with 60% by mass sulfuric acid at 45° C. until dissolved, and terminating the acid hydrolysis process by diluting it with 10 times ice water to obtain a nanocellulose mixed solution;

[0062] (6) washing the obtained nanocellulose mixed solution with deionized water and centrifuging at 8000 rpm for 10 minutes, then repeating the centrifugation 3 to 5 times, and dialyzing the solution for about 3-4 days until it is neutral;

[0063] (7) using a cell disruptor to ultrasonically treat the nanocellulose mixed solution at 600 W to obtain a stable nanocellulose suspension;

[0064] (8) The nanocellulose suspension is placed in an oven at 80° C. and heated to constant weight to obtain nanocellulose.

[0065] Further, the electrospinning liquid is electrospun by an electrospinning device to prepare a TPU melt-blown fabric layer, and the specific steps are as follows:

[0066] D1. Take the base fabric and wrap it on the drum for receiving, load the electrospinning solution into the syringe, and set the distance between the drum and the needle tip to 19 cm;

[0067] D2. Setting the electrospinning parameters, applying a voltage of 18 kV, and a solution feed rate of 1.2 mL / h, electrospinning the prepared electrospinning solution onto the surface of the base fabric to obtain a TPU meltblown fabric semi-finished product;

[0068] D3. The prepared TPU meltblown fabric layer semi-finished product was removed from the base fabric and dried in a vacuum oven at 70° C. for 5.5 h to ensure that all the solvent was volatilized, thereby obtaining a TPU meltblown fabric layer.

[0069] In this embodiment, the base fabric is a twill polyester fabric.

[0070] The present invention also provides a method for preparing a recyclable TPU non-woven leather, comprising the following steps:

[0071] (1) At room temperature, a polyurethane coating is applied to the upper surface of the TPU meltblown fabric layer to form a PU coating;

[0072] (2) The PU coating is hot-pressed at 105° C. using an embossing roller to form an uneven texture structure on the upper surface of the PU coating, thereby obtaining a PU texture layer.

[0073] Example 2

[0074] In this embodiment, the TPU meltblown fabric layer is made of an electrospinning solution, and the electrospinning solution includes 100 parts of an organic solvent, 7 parts of a foaming agent, 10 parts of nanocellulose and 18 parts of polyether TPU particles.

[0075] Furthermore, the preparation method of the electrospinning solution comprises the following steps: dissolving a foaming agent, nanocellulose and polyether TPU particles in an organic solvent and stirring the mixture evenly to obtain an electrospinning solution.

[0076] Further, the electrospinning liquid is electrospun by an electrospinning device to prepare a TPU melt-blown fabric layer, and the specific steps are as follows:

[0077] D1. Take the base fabric and wrap it on the drum for receiving, load the electrospinning solution into the syringe, and set the distance between the drum and the needle tip to 19 cm;

[0078] D2. Setting the electrospinning parameters, applying a voltage of 18 kV, and a solution feed rate of 1.2 mL / h, electrospinning the prepared electrospinning solution onto the surface of the base fabric to obtain a TPU meltblown fabric semi-finished product;

[0079] D3. The prepared TPU meltblown fabric layer semi-finished product was removed from the base fabric and dried in a vacuum oven at 70° C. for 5.5 h to ensure that all the solvent was volatilized, thereby obtaining a TPU meltblown fabric layer.

[0080] The present invention also provides a method for preparing a recyclable TPU non-woven leather, comprising the following steps:

[0081] (1) At room temperature, a polyurethane coating is applied to the upper surface of the TPU meltblown fabric layer to form a PU coating;

[0082] (2) The PU coating is hot-pressed at 105° C. using an embossing roller to form an uneven texture structure on the upper surface of the PU coating, thereby obtaining a PU texture layer.

[0083] The rest of the content of this embodiment is the same as that of Embodiment 1.

[0084] Example 3

[0085] In this embodiment, the TPU meltblown fabric layer is made of an electrospinning solution, and the electrospinning solution includes 100 parts of an organic solvent, 8 parts of a foaming agent, 12 parts of nanocellulose, and 20 parts of polyether TPU particles.

[0086] Furthermore, the preparation method of the electrospinning solution comprises the following steps: dissolving a foaming agent, nanocellulose and polyether TPU particles in an organic solvent and stirring the mixture evenly to obtain an electrospinning solution.

[0087] Further, the electrospinning liquid is electrospun by an electrospinning device to prepare a TPU melt-blown fabric layer, and the specific steps are as follows:

[0088] D1. Take the base fabric and wrap it on the drum for receiving, load the electrospinning solution into the syringe, and set the distance between the drum and the needle tip to 19 cm;

[0089] D2. Setting the electrospinning parameters, applying a voltage of 18 kV, and a solution feed rate of 1.2 mL / h, electrospinning the prepared electrospinning solution onto the surface of the base fabric to obtain a TPU meltblown fabric semi-finished product;

[0090] D3. The prepared TPU meltblown fabric layer semi-finished product was removed from the base fabric and dried in a vacuum oven at 70° C. for 5.5 h to ensure that all the solvent was volatilized, thereby obtaining a TPU meltblown fabric layer.

[0091] The present invention also provides a method for preparing a recyclable TPU non-woven leather, comprising the following steps:

[0092] (1) At room temperature, a polyurethane coating is applied to the upper surface of the TPU meltblown fabric layer to form a PU coating;

[0093] (2) The PU coating is hot-pressed at 105° C. using an embossing roller to form an uneven texture structure on the upper surface of the PU coating, thereby obtaining a PU texture layer.

[0094] The rest of the content of this embodiment is the same as that of Embodiment 1.

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 2 is that an equal amount of soybean oil polyol is used to replace the modified soybean oil polyol, that is, the soybean oil polyol is not modified.

[0097] Furthermore, the preparation method of the polyurethane coating comprises the following steps:

[0098] B1. Place polyethylene glycol and soybean oil polyol under protective gas protection, dehydrate at 110° C. for 2 hours, cool to 80° C., add hexamethylene diisocyanate, dimethylol propionic acid and an organic tin catalyst, and react for 2.5 hours to obtain a polyurethane prepolymer;

[0099] B2. Add sodium bisulfite as a capping agent to the polyurethane prepolymer and continue the reaction at 80° C. for 1.5 hours to obtain a polyurethane prepolymer.

[0100] Furthermore, the molar ratio of the polyethylene glycol, soybean oil polyol, dimethylol propionic acid, hexamethylene diisocyanate and sodium bisulfite is 0.7:0.3:1:1.5:0.2. The amount of the organic tin catalyst added is 0.08% of the total amount of the polyethylene glycol, soybean oil polyol, dimethylol propionic acid and hexamethylene diisocyanate; the amount of the deionized water added is 85% of the total amount of the polyethylene glycol, soybean oil polyol, dimethylol propionic acid and hexamethylene diisocyanate.

[0101] The present invention also provides a method for preparing a recyclable TPU non-woven leather, comprising the following steps:

[0102] (1) At room temperature, a polyurethane coating is applied to the upper surface of the TPU meltblown fabric layer to form a PU coating;

[0103] (2) The PU coating is hot-pressed at 105° C. using an embossing roller to form an uneven texture structure on the upper surface of the PU coating, thereby obtaining a PU texture layer.

[0104] Comparative Example 2

[0105] The difference between this comparative example and Example 2 is that the nanocellulose is extracted from cotton straw. The preparation method of the nanocellulose comprises the following steps:

[0106] (1) Wash the cotton stalks thoroughly with warm water for 4-5 times to remove dirt and water-soluble substances, and then dry them for 24 hours. Cut the cleaned cotton stalks into 4-5 mm pieces to obtain cotton stalk fragments;

[0107] (2) toluene and ethanol were mixed in a volume ratio of 2:1 to prepare a mixed solvent, 10 g of cotton straw fragments were immersed in the mixed solvent for 6 h for extraction to remove wax, pigment and oil, and then dried at 45 °C for 10 h to obtain pretreated cotton straw A;

[0108] (3) The cotton straw of pretreatment A was immersed in 0.7% NaCl 2 O, the pH was adjusted to 3.5 with glacial acetic acid, and the lignin in the cotton straw was dissolved at 90°C for 1 hour. This step was repeated twice to obtain pretreated cotton straw B;

[0109] (4) The pretreated cotton stalk B was immersed in 5% KOH at 90° C. for 2 h, filtered and washed, and then extracted with 10% KOH at 90° C. for 2 h. Finally, it was washed with a large amount of water until the filtrate reached neutrality, thereby obtaining pretreated cotton stalk C;

[0110] (5) hydrolyzing the pretreated cotton straw C with 60% sulfuric acid at 45° C. until dissolved, and terminating the acid hydrolysis process by diluting with 10 times ice water to obtain a nanocellulose mixed solution;

[0111] (6) washing the obtained nanocellulose mixed solution with deionized water and centrifuging at 8000 rpm for 10 minutes, then repeating the centrifugation 3 to 5 times, and dialyzing the solution for about 3-4 days until it is neutral;

[0112] (7) using a cell disruptor to ultrasonically treat the nanocellulose mixed solution at 600 W to obtain a stable nanocellulose suspension;

[0113] (8) The nanocellulose suspension is placed in an oven at 80° C. and heated to constant weight to obtain nanocellulose.

[0114] Performance testing

[0115] The performance tests were performed on the recyclable TPU non-woven leathers prepared in Examples 1-3 and Comparative Examples 1-2.

[0116] 1. The Shore hardness, tensile properties, adhesion and water vapor permeability of the recyclable TPU non-woven leather of Examples 1-3 and Comparative Example 1 were tested. The test data are shown in Table 1 below:

[0117] Table 1

[0118]

[0119]

[0120] Among them, the hardness test adopts the standard GB / T 531.1-2008 / ISO 7619-1:2004, and the hardness of the sample is tested using a Shore hardness tester;

[0121] The tensile test was conducted on a CHD-1000A tensile testing machine produced by Dongguan Chengding Instrument Technology Co., Ltd., which has a 10kN load cell. According to DIN standards, the tensile speed is 500mm / min;

[0122] Water vapor transmission rate (g / m 2 24h): Tested according to GB / T1037-2021 Plastic film and sheeting - Determination of water vapor transmission rate - Humidity sensor method.

[0123] The adhesion test adopts GB / T9286-1998 to test the adhesion of the PU texture layer to the TPU meltblown fabric layer.

[0124] 2. The antibacterial properties of the recyclable TPU non-woven leathers of Example 2 and Comparative Examples 1-2 were tested. The test data are shown in Table 2 below:

[0125] Table 2

[0126]

[0127] Antibacterial test Antibacterial test is carried out according to JISZ2801:2000 standard.

[0128] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A recyclable TPU non-woven leather, characterized in that: It includes a PU texture layer and a TPU meltblown fabric layer which are arranged in sequence from top to bottom.

2. The recyclable TPU non-woven leather according to claim 1, characterized in that: The PU texture layer is made of polyurethane coating.

3. The recyclable TPU non-woven leather according to claim 2, characterized in that: The preparation method of the polyurethane coating comprises the following steps: B1. Place polyethylene glycol and modified soybean oil polyol under protective gas protection, dehydrate at 105-115° C. for 1-3 hours, cool to 75-85° C., add hexamethylene diisocyanate, dimethylol propionic acid and an organic tin catalyst, and react for 2-3 hours to obtain a polyurethane prepolymer; B2. Add sodium bisulfite as a capping agent to the polyurethane prepolymer and continue the reaction at 75-85° C. for 2-3 hours to obtain a polyurethane prepolymer.

4. The recyclable TPU non-woven leather according to claim 3, characterized in that: The molar ratio of the polyethylene glycol, modified soybean oil polyol, dimethylol propionic acid, hexamethylene diisocyanate and sodium bisulfite is 0.6-0.8: 0.2-0.4: 0.8-1.2: 1-3: 0.1-0.

3.

5. The recyclable TPU non-woven leather according to claim 1, characterized in that: The TPU melt-blown fabric layer is made of an electrostatic spinning solution, which includes 100 parts of an organic solvent, 4-10 parts of a foaming agent, 7-12 parts of nanocellulose and 16-20 parts of polyether TPU particles.

6. The recyclable TPU non-woven leather according to claim 5, characterized in that: The foaming agent is sodium bicarbonate.

7. The recyclable TPU non-woven leather according to claim 5, characterized in that: The preparation method of the electrospinning solution comprises the following steps: dissolving a foaming agent, nanocellulose and polyether TPU particles in an organic solvent and stirring the mixture evenly to obtain the electrospinning solution.

8. The recyclable TPU non-woven leather according to claim 5, characterized in that: The nanocellulose is extracted from the needles of pine trees.

9. The recyclable TPU non-woven leather according to claim 7, characterized in that: The electrospinning equipment is used to electrospin the electrospinning solution to prepare the TPU melt-blown cloth layer. The specific steps are as follows: D1. Take the base fabric and wrap it on the rotating drum for receiving, load the electrospinning solution into the syringe, and set the distance between the rotating drum and the needle tip to 18-20 cm; D2. Setting the electrospinning parameters, applying a voltage of 15-20 kV, and a solution feed rate of 1-1.5 mL / h, electrospinning the prepared electrospinning solution onto the surface of the base fabric to obtain a TPU meltblown fabric semi-finished product; D3. Remove the prepared TPU meltblown fabric layer semi-finished product from the base fabric and dry it in a vacuum oven at 60-75°C for 5-6 hours to ensure that all the solvent is evaporated to obtain the TPU meltblown fabric layer.

10. A method for preparing a recyclable TPU non-woven leather according to any one of claims 1 to 9, characterized in that: The steps include: (1) At room temperature, a polyurethane coating is applied to the upper surface of the TPU meltblown fabric layer to form a PU coating; (2) The PU coating is hot-pressed at 95-115° C. using an embossing roller to form an uneven texture structure on the upper surface of the PU coating, thereby obtaining a PU texture layer.

Images