Multi-scale superfine fiber leather base cloth, synthetic leather and preparation method thereof

Abstract

The invention provides multi-scale superfine fiber leather base cloth, synthetic leather and a preparation method of the synthetic leather. The multi-scale superfine fiber leather base cloth is obtained by spinning a spinning solution through a flash evaporation method; the spinning solution is prepared from the following raw materials in parts by mass: 50 to 100 parts of ultra-high molecular weight polyethylene, 0 to 50 parts of polyamide polymer and 10 to 5000 parts of solvent; the mass ratio of the ultra-high molecular weight polyethylene to the polyamide polymer is (1-20): 1. The superfine fiber leather base cloth has multi-scale superfine fibers, can achieve a more real effect of imitating collagen fibers of leather, has high strength and high tear resistance, and is higher in production efficiency due to the fact that splitting is not needed in the preparation method.

Description

Technical Field

[0001] The invention belongs to the technical field of synthetic leather, and in particular relates to a multi-scale ultrafine fiber leather base cloth, synthetic leather and a preparation method thereof. Background Art

[0002] Synthetic leather is based on the internal structure and comprehensive performance of genuine leather. It uses polyurethane and its additives as raw materials, and forms a polyurethane film on the surface or inside of the substrate by coating or impregnation. The fiber substrate imitates the three-dimensional structure inside the leather, and the polyurethane forms a membrane with a microporous structure inside or on the surface after solidification, so as to achieve the purpose of fiber composite materials comparable to genuine leather in structure and performance.

[0003] At present, the fiber substrates commonly used in the preparation of synthetic leather mainly include knitted fabrics, woven fabrics, ordinary chemical fiber non-woven fabrics and ultrafine fiber non-woven fabrics. Among them, the fiber materials used in woven fabrics and knitted fabrics have a higher fiber diameter and higher fiber bending stiffness, which leads to a great difference in feel and elasticity from genuine leather products, and can only be used for the production of medium and low-end simulated leather products; and although the fiber diameter of ordinary chemical fibers is lower than that of the fiber materials used in knitted fabrics and woven fabrics, there is still a large gap with collagen fibers, so there are still deficiencies in softness and feel, and it is difficult to meet the performance requirements of high-end simulated leather products; and ultrafine fiber non-woven fabrics, on the one hand, imitate the three-dimensional structure of genuine leather products, and on the other hand, the fiber fineness is close to the diameter of collagen fibers in natural leather, so as to achieve a better simulated leather effect, which is a good substitute for natural leather on the market. At the same time, ultrafine fiber synthetic leather has also become a key research direction in the field of simulated leather.

[0004] At present, the base fabric that can be used for microfiber synthetic leather is mainly prepared by a composite spinning method to prepare a two-component microfiber non-woven base fabric (sea island microfiber needle-punched non-woven fabric and hollow orange-peel type microfiber non-woven fabric), which is then combined with an alkali reduction fiber opening process to obtain microfibers. For example, a Chinese patent document with publication number CN111926581A discloses a benzene-reduced water-based impregnated ultrafine fiber synthetic leather and a processing method thereof, comprising mixing recycled PET slices, PA slices, and PE slices in a certain proportion, and obtaining a blended sea island fiber through a spinning process; manufacturing an ultrafine fiber non-woven fabric from the blended sea island fiber through a needle punching process; shaping the ultrafine fiber non-woven fabric through a shaping process to obtain a base fabric; impregnating the base fabric with an aqueous polyurethane slurry, and placing the impregnated base fabric in an oven to dry to obtain a semi-finished product to be opened; opening the semi-finished product to be opened by a benzene-reduced method to obtain a semi-finished product to be opened; drying the semi-finished product to be opened and oiling it for finalizing it, and kneading the semi-finished product after finalizing it; veneering the semi-finished product after kneading with an aqueous resin to obtain a benzene-reduced water-based impregnated ultrafine fiber synthetic leather. However, dermal collagen fibers have varying degrees of fineness (diameter 0.5 to 20 um), are highly dispersed, and present a multi-scale structure (multi-scale fiber overlap from micrometer scale to nanometer scale). The ultrafine fibers prepared by the composite spinning combined with the fiber-opening process are mostly of a single scale, and multi-scale fibers cannot be prepared, and thus the effect of completely simulating dermal collagen fibers cannot be achieved. In addition, the additional fiber-opening process makes the production process more complicated, and the fiber-opening effect will have a great impact on subsequent applications, and the strength and high tear resistance still need to be improved. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a multi-scale ultrafine fiber leather base cloth, synthetic leather and a preparation method thereof. The ultrafine fiber leather base cloth has multi-scale ultrafine fibers and can achieve a more realistic simulated leather collagen fiber effect. The ultrafine fiber leather base cloth has high strength and high tear resistance. The preparation method does not require fiber opening and has higher production efficiency.

[0006] In order to solve the above problems, the first object of the present invention is to provide a multi-scale ultrafine fiber leather base fabric, wherein the multi-scale ultrafine fiber leather base fabric is obtained by spinning a spinning solution by flash evaporation; the raw materials of the spinning solution include the following components in parts by weight:

[0007] 50-100 parts of ultra-high molecular weight polyethylene, 0-50 parts of polyamide polymer, and 10-5000 parts of solvent; the mass ratio of ultra-high molecular weight polyethylene to polyamide polymer is 1-20:1.

[0008] Preferably, the raw materials of the spinning solution include the following components in parts by weight:

[0009] 65-90 parts of ultra-high molecular weight polyethylene, 10-35 parts of polyamide polymer, and 500-3000 parts of solvent; the mass ratio of ultra-high molecular weight polyethylene to polyamide polymer is 2-9:1.

[0010] Preferably, the molecular weight of the ultra-high molecular weight polyethylene is 150w-300w; the molecular weight of the polyamide polymer is 2w-8w;

[0011] The polyamide polymer is a mixture of one or more of high viscosity polyamide 6 with a relative viscosity of 3.35-3.45, high viscosity polyamide 66 with a relative viscosity of 4.75-5.35, and high viscosity polyamide 56 with a relative viscosity of 3.00-4.00.

[0012] Preferably, the raw materials of the spinning solution further include the following components in parts by weight:

[0013] 0-5 parts of hydrophilic agent, 0-3 parts of anti-ultraviolet agent, 0-5 parts of antibacterial agent, 0-3 parts of flame retardant, and 0-4 parts of antistatic agent.

[0014] The second object of the present invention is to provide a method for preparing the above-mentioned multi-scale ultrafine fiber leather base fabric, comprising the following steps:

[0015] S1. According to the mass fraction, the raw materials of the spinning solution are mixed to obtain a spinning solution;

[0016] S2. Using the spinning solution, spinning by flash evaporation to obtain a flash multi-scale ultrafine fiber web;

[0017] S3. The flash-steamed multi-scale ultrafine fiber web is spunlaced to obtain a multi-scale ultrafine fiber spunlaced fabric;

[0018] S4. heat-setting the multi-scale microfiber spunlace fabric to obtain the multi-scale microfiber leather base fabric.

[0019] Preferably, step S2 specifically includes the following steps: transferring the spinning solution to a high-temperature and high-pressure reactor with a temperature of 100 to 400° C. and a pressure of 3 to 30 MPa, and ejecting the spinning solution from the spinneret through the spinning assembly, releasing the pressure of the spinning solution after ejection, and the solvent absorbing a large amount of heat and evaporating rapidly, thereby generating a high-speed airflow, while the polymer cools and solidifies and is stretched by the airflow, thereby forming a flash-evaporated multi-scale ultrafine fiber web on the receiving device;

[0020] Step S3 specifically includes the following steps: pre-piercing the flash-evaporated multi-scale ultrafine fiber web through a low-pressure spunlace head with a water pressure of 20 to 50 MPa, and then passing through a high-pressure spunlace head with a water pressure of 50 to 120 MPa, using a high-pressure water jet to entangle the multi-scale ultrafine fibers in the flash-evaporated multi-scale ultrafine fiber web with each other, thereby obtaining the multi-scale ultrafine fiber spunlace cloth;

[0021] Step S4 specifically includes the following steps: transporting the multi-scale microfiber spunlace fabric to a heat setting machine, and heat setting it at a temperature of 80 to 110° C. for 3 to 120 minutes to obtain the multi-scale microfiber leather base fabric.

[0022] Preferably, in step S2, the temperature of the high temperature and high pressure reactor is 150-300°C and the pressure is 5-25MPa;

[0023] In step S3, the water pressure of the low-pressure water jet is 20-35 MPa, and the water pressure of the high-pressure water jet is 70-100 MPa;

[0024] In step S4, the temperature of the heat setting treatment is 90-100° C., and the treatment time is 5-80 minutes.

[0025] The third object of the present invention is to provide a multi-scale ultrafine fiber synthetic leather, comprising the above-mentioned multi-scale ultrafine fiber leather base cloth, wherein the fibers of the multi-scale ultrafine fiber leather base cloth are filled with polyurethane material.

[0026] Preferably, the filling rate of the polyurethane material in the multi-scale microfiber leather base fabric is 25% to 125%.

[0027] The fourth object of the present invention is to provide a method for preparing the above-mentioned multi-scale ultrafine fiber synthetic leather, comprising the following steps:

[0028] The multi-scale superfine fiber leather base cloth is coated or impregnated with polyurethane material on its surface and inside, and then dried and shaped to obtain the multi-scale superfine fiber synthetic leather.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The multi-scale ultrafine fiber leather base cloth of the present invention uses ultra-high molecular weight polyethylene and polyamide polymers as raw materials. Since the spinning system contains two low-compatible components, ultra-high molecular weight polyethylene and high-viscosity polyamide, the ultra-high molecular weight polyethylene component has a large molecular weight and is easy to form thicker trunk fibers, and the polyamide polymer component has a small molecular weight and is easy to form fine branch fibers. Based on the flash non-woven technology, multi-scale ultrafine fibers can be prepared on a large scale, which can achieve a more realistic simulated leather collagen fiber effect.

[0031] The multi-scale ultrafine fiber leather base fabric of the present invention adds a polyamide polymer and a hydrophilic agent during the flash evaporation process, so that the fibers are more easily entangled during the subsequent hydroentanglement process, which helps to achieve high strength and high tear resistance of the ultrafine fiber leather base fabric.

[0032] The preparation method of the multi-scale ultrafine fiber leather base fabric of the present invention does not require fiber opening in the entire preparation process of the flash vaporized multi-scale ultrafine fiber spunlace leather base fabric, and has higher production efficiency.

[0033] The multi-scale ultrafine fiber synthetic leather of the present invention has better interface bonding strength between the multi-scale ultrafine fiber structure and a matrix such as polyurethane than conventional ultrafine fibers, forming a "root-soil"-like structure. The thicker fibers play an anchoring and reinforcing role, and the thinner roots can effectively control the displacement of the shallow polyurethane, firmly supporting the synthetic leather to resist wear, thereby obtaining a multi-scale ultrafine fiber synthetic leather with high strength and high tear resistance, which has a better simulated leather effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a scanning electron microscope image of the multi-scale ultrafine fiber synthetic leather prepared in Example 1 of the present invention;

[0035] Figure 2 is a scanning electron microscope image of the multi-scale ultrafine fiber synthetic leather prepared in Example 2 of the present invention;

[0036] Figure 3 is a scanning electron microscope image of the multi-scale ultrafine fiber synthetic leather prepared in Example 3 of the present invention;

[0037] Figure 4 This is a scanning electron microscope image of the ultrafine fiber synthetic leather prepared in Comparative Example 1;

[0038] Figure 5 This is a scanning electron microscope image of the ultrafine fiber synthetic leather prepared in Comparative Example 2. DETAILED DESCRIPTION

[0039] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The first purpose of the embodiment of the present invention is to provide a multi-scale ultrafine fiber leather base fabric, wherein the multi-scale ultrafine fiber leather base fabric is obtained by spinning a spinning solution through a flash evaporation method; the raw materials of the spinning solution include the following components in parts by weight:

[0041] 50-100 parts of ultra-high molecular weight polyethylene, 0-50 parts of polyamide polymer, and 10-5000 parts of solvent; the mass ratio of ultra-high molecular weight polyethylene to polyamide polymer is 1-20:1.

[0042] The multi-scale ultrafine fiber leather base cloth of the present invention uses ultra-high molecular weight polyethylene and polyamide polymers as raw materials and is flash-spun. Two low-compatible polymer solutions are above the boiling point of the solvent and are extruded through a spinneret under high pressure at the same time. The pressure drops suddenly and the solvent evaporates rapidly. Since polyethylene and polyamide have low compatibility, the two phases are separated. The ultra-high molecular weight polyethylene component has a large molecular weight and is easy to form a relatively thick trunk fiber. The polyamide polymer component has a small molecular weight and is easy to form fine branch fibers, thereby forming multi-scale ultrafine fibers. The interface bonding strength between the multi-scale ultrafine fiber structure and a matrix such as polyurethane is better than that of conventional ultrafine fibers, forming a "root-soil" structure. The thicker fibers play an anchoring and reinforcing role, and the thinner roots can effectively control the displacement of the shallow polyurethane, firmly support the synthetic leather to resist wear, and obtain a high-strength, high-tear resistance multi-scale ultrafine fiber synthetic leather with a better simulated leather effect.

[0043] Preferably, the raw materials of the spinning solution include the following components in parts by weight:

[0044] 65-90 parts of ultra-high molecular weight polyethylene, 10-35 parts of polyamide polymer, 500-3000 parts of solvent; the mass ratio of ultra-high molecular weight polyethylene to polyamide polymer is 2-9: 1. Within the above mass fraction range, the obtained multi-scale ultra-fine fiber leather base fabric can have a more realistic effect of simulated leather collagen fiber.

[0045] Preferably, the molecular weight of the ultra-high molecular weight polyethylene is 150w-300w. If the molecular weight of polyethylene is too high, the viscosity of the spinning solution will increase, which will make it difficult to form and spin during processing, affecting the mechanical properties of the final synthetic leather. If the molecular weight of polyethylene is too low, the strength and toughness of polyethylene will be reduced, affecting the performance of the final product.

[0046] Preferably, the molecular weight of the polyamide polymer is 2w-8w. If the molecular weight of the polyamide polymer is too high, the viscosity of the spinning solution will increase, which will make it difficult to form and spin during processing, affecting the mechanical properties of the final synthetic leather. If the molecular weight of the polyamide polymer is too low, the strength and toughness of the polyethylene will be reduced, affecting the performance of the final product.

[0047] Preferably, the polyamide polymer is a mixture of one or more of high viscosity polyamide 6 with a relative viscosity of 3.35-3.45, high viscosity polyamide 66 with a relative viscosity of 4.75-5.35, and high viscosity polyamide 56 with a relative viscosity of 3.00-4.00.

[0048] Preferably, the solvent is one or more of aromatic hydrocarbons (such as benzene, toluene), halogenated hydrocarbons (such as dichloromethane, carbon tetrachloride, chloroform, chloromethane, trichlorofluoromethane, ethyl chloride and dichloroethylene), aliphatic hydrocarbons (such as butane, pentene, n-hexane, heptane, octane and isomers thereof), alicyclic hydrocarbons (such as cyclohexane, unsaturated hydrocarbons), and alcohols (methanol and tert-butyl alcohol).

[0049] Preferably, the raw materials of the spinning solution further include the following components in parts by weight:

[0050] The hydrophilic agent is 0 to 5 parts. More preferably, the hydrophilic agent is 2 to 5 parts.

[0051] Preferably, the hydrophilic agent can be one or a combination of polyvinyl alcohol, polyvinyl alcohol ether, polyacrylic acid, sodium polyacrylate. Further preferably, the hydrophilic agent is polyvinyl alcohol.

[0052] The hydrophilic agent can improve the hydrophilicity and help the subsequent hydroentanglement treatment. The introduction of the hydrophilic agent into the spinning solution can make it easier for the fibers to be entangled during the subsequent hydroentanglement solidification process, which helps to achieve the high strength and high tear resistance of the ultrafine fiber leather base fabric.

[0053] The hydrophilic agent may specifically be polyacrylic acid.

[0054] Preferably, the raw materials of the spinning solution further include the following components in parts by weight:

[0055] The amount of the anti-ultraviolet agent is 0 to 3 parts. More preferably, the amount of the anti-ultraviolet agent is 1 to 2 parts.

[0056] The UV-blocking agent may specifically be titanium dioxide particles.

[0057] Preferably, the raw materials of the spinning solution further include the following components in parts by weight:

[0058] The antibacterial agent is 0 to 5 parts. More preferably, the antibacterial agent is 2 to 4 parts.

[0059] The antibacterial agent may specifically be silver particles.

[0060] Preferably, the raw materials of the spinning solution further include the following components in parts by weight:

[0061] The flame retardant is 0 to 3 parts. More preferably, the flame retardant is 1 to 2 parts.

[0062] The flame retardant may specifically be a halogenated phosphate ester.

[0063] Preferably, the raw materials of the spinning solution further include the following components in parts by weight:

[0064] The antistatic agent is 0 to 4 parts. More preferably, the antistatic agent is 1 to 3 parts.

[0065] The antistatic agent may specifically be carbon black.

[0066] Preferably, the multi-scale ultrafine fiber leather base fabric has a fiber diameter of 0.02-20.00 μm, presenting a multi-scale fiber interlaced arrangement of simulated leather collagen fibers, and a gram weight of 50-700 g / m 2 .

[0067] The second object of the present invention is to provide a method for preparing the above-mentioned multi-scale ultrafine fiber leather base fabric, comprising the following steps:

[0068] S1. According to the mass fraction, the raw materials of the spinning solution are mixed to obtain a spinning solution;

[0069] S2. Using the spinning solution, spinning by flash evaporation to obtain a flash multi-scale ultrafine fiber web;

[0070] S3. The flash-steamed multi-scale ultrafine fiber web is spunlaced to obtain a multi-scale ultrafine fiber spunlaced fabric;

[0071] S4. heat-setting the multi-scale microfiber spunlace fabric to obtain the multi-scale microfiber leather base fabric.

[0072] The preparation method of the multi-scale ultrafine fiber leather base cloth of the present invention adopts the flash evaporation non-woven material production technology, and the two low-compatible polymer solutions of ultra-high molecular weight polyethylene and polyamide polymer are placed above the boiling point of the solvent, and are extruded through a spinneret under high pressure at the same time, the pressure drops suddenly, the solvent evaporates rapidly, and because polyethylene and polyamide have low compatibility, the two phase separate, the ultra-high molecular weight polyethylene component has a large molecular weight and is easy to form a relatively thick trunk fiber, and the polyamide polymer component has a small molecular weight and is easy to form fine branch fibers, forming multi-scale ultrafine fibers, and the flash multi-scale ultrafine fiber non-woven fabric is obtained by filament separation and laying, and then combined with water spunlace fixed net and heat setting, the flash multi-scale ultrafine fiber leather base cloth is obtained, and the effect of forming simulated leather collagen fiber is formed. The preparation method prepares multi-scale ultrafine fiber leather base cloth, and the entire preparation process does not need to be opened, and the production efficiency is higher.

[0073] Preferably, step S2 specifically includes the following steps: transferring the spinning solution to a high-temperature and high-pressure reactor with a temperature of 100 to 400° C. and a pressure of 3 to 30 MPa, and ejecting the spinning solution from the spinneret through the spinning assembly, releasing the pressure of the spinning solution after ejection, and the solvent absorbing a large amount of heat and evaporating rapidly, thereby generating a high-speed airflow, while the polymer cools and solidifies and is stretched by the airflow, thereby forming a flash-evaporated multi-scale ultrafine fiber web on the receiving device;

[0074] Step S3 specifically includes the following steps: pre-piercing the flash-evaporated multi-scale ultrafine fiber web through a low-pressure spunlace head with a water pressure of 20 to 50 MPa, and then passing through a high-pressure spunlace head with a water pressure of 50 to 120 MPa, using a high-pressure water jet to entangle the multi-scale ultrafine fibers in the flash-evaporated multi-scale ultrafine fiber web with each other, thereby obtaining the multi-scale ultrafine fiber spunlace cloth;

[0075] Step S4 specifically includes the following steps: transporting the multi-scale microfiber spunlace fabric to a heat setting machine, and heat setting it at a temperature of 80 to 110° C. for 3 to 120 minutes to obtain the multi-scale microfiber leather base fabric.

[0076] Preferably, in step S2, the temperature of the high temperature and high pressure reactor is 150-300°C and the pressure is 5-25MPa;

[0077] In step S3, the water pressure of the low-pressure water jet is 20-50 MPa, and the water pressure of the high-pressure water jet is 50-120 MPa;

[0078] In step S4, the temperature of the heat setting treatment is 90-100° C., and the treatment time is 5-80 minutes.

[0079] The third object of the present invention is to provide a multi-scale ultrafine fiber synthetic leather, comprising the above-mentioned multi-scale ultrafine fiber leather base cloth, wherein the fibers of the multi-scale ultrafine fiber leather base cloth are filled with polyurethane material.

[0080] The multi-scale ultrafine fiber synthetic leather is made by combining a multi-scale ultrafine fiber leather base cloth with a polyurethane material. The multi-scale structure of the ultrafine fiber leather base cloth makes the interface bonding strength between the ultrafine fiber leather base cloth and the polyurethane matrix better than that of conventional ultrafine fibers, forming a "root-soil" structure. The thicker fibers play an anchoring and reinforcing role, and the thinner roots can effectively control the displacement of the shallow polyurethane, firmly supporting the synthetic leather to resist wear, thereby obtaining a multi-scale ultrafine fiber synthetic leather with high strength and high tear resistance, achieving a better simulated leather effect of the flash-steamed ultrafine fiber spunlace synthetic leather.

[0081] Preferably, the filling rate of the polyurethane material in the multi-scale microfiber leather base fabric is 25% to 125%. The filling rate is calculated as follows: the mass fraction of the filled polyurethane material in the final multi-scale microfiber synthetic leather.

[0082] Further preferably, the filling rate of the polyurethane material in the multi-scale microfiber leather base fabric is 40% to 110%.

[0083] The fourth object of the present invention is to provide a method for preparing the above-mentioned multi-scale ultrafine fiber synthetic leather, comprising the following steps:

[0084] The multi-scale superfine fiber leather base cloth is coated or impregnated with polyurethane material on its surface and inside, and then dried and shaped to obtain the multi-scale superfine fiber synthetic leather.

[0085] Example 1

[0086] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric include the following components in parts by mass:

[0087] 80 parts of ultra-high molecular weight polyethylene with a molecular weight of 180w, 20 parts of high viscosity polyamide 6 with a molecular weight of 6w and a relative viscosity of 3.40, 1700 parts of dichloromethane, 5 parts of hydrophilic agent polyacrylic acid, 2 parts of UV inhibitor titanium dioxide particles, 2 parts of antibacterial agent silver particles, 3 parts of flame retardant halogenated phosphate, and 2 parts of antistatic agent carbon black.

[0088] The method for preparing the multi-scale ultrafine fiber synthetic leather of this embodiment comprises the following steps:

[0089] S1. According to the above mass fractions, the raw materials of the spinning solution are mixed to obtain the spinning solution.

[0090] S2. The spinning solution is transferred to a high-temperature and high-pressure reactor with a temperature of 180°C and a pressure of 15MPa, and is ejected from the spinneret through the spinning assembly. The spinning solution is depressurized after being ejected, and the solvent absorbs a large amount of heat and evaporates rapidly to generate a high-speed airflow. At the same time, the polymer is cooled and solidified, and is stretched by the airflow to form a fiber with a diameter of 0.10-15.00μm and a gram weight of 300g / m on the receiving device. 2 Flash-steamed multi-scale microfiber webs.

[0091] S3. The prepared flash-steamed multi-scale ultrafine fiber web is pre-punched by a low-pressure hydrojet head with a water pressure of 30 MPa, and then passed through a high-pressure hydrojet head with a water pressure of 90 MPa. The multi-scale ultrafine fibers in the flash-steamed multi-scale ultrafine fiber web are entangled with each other by using a high-pressure water jet to obtain a multi-scale ultrafine fiber spunlace cloth.

[0092] S4. The multi-scale microfiber spunlace fabric is transported to a heat setting machine and heat-set at 95°C for 20 minutes to obtain a dense multi-scale microfiber leather base fabric.

[0093] S5. The surface and interior of the dense multi-scale microfiber leather base fabric are filled with polyurethane by coating or impregnation, with a filling rate of 100%. After drying and shaping, the multi-scale microfiber synthetic leather is obtained.

[0094] Example 2

[0095] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric include the following components in parts by mass:

[0096] 70 parts of ultra-high molecular weight polyethylene with a molecular weight of 150w, 30 parts of high viscosity polyamide 66 with a molecular weight of 8w and a relative viscosity of 5.25, 2500 parts of dichloromethane, 3 parts of hydrophilic agent polyacrylic acid, 2 parts of anti-ultraviolet agent titanium dioxide particles, and 4 parts of antistatic agent carbon black.

[0097] The method for preparing the multi-scale ultrafine fiber synthetic leather of this embodiment comprises the following steps:

[0098] S1. According to the above mass fractions, the raw materials of the spinning solution are mixed to obtain the spinning solution.

[0099] S2. The spinning solution is transferred to a high-temperature and high-pressure reactor at a temperature of 150°C and a pressure of 12MPa, and is ejected from the spinneret through the spinning assembly. The spinning solution is depressurized after being ejected, and the solvent absorbs a large amount of heat and evaporates rapidly to generate a high-speed airflow. At the same time, the polymer is cooled and solidified, and is stretched by the airflow to form a fiber with a diameter of 0.80 to 20.00 μm and a gram weight of 200 g / m on the receiving device. 2 Flash-steamed multi-scale microfiber webs.

[0100] S3. The prepared flash-steamed multi-scale ultrafine fiber web is pre-punched by a low-pressure hydrojet head with a water pressure of 40 MPa, and then passed through a high-pressure hydrojet head with a water pressure of 100 MPa. The multi-scale ultrafine fibers in the flash-steamed multi-scale ultrafine fiber web are entangled with each other by using a high-pressure water jet to obtain a multi-scale ultrafine fiber spunlace cloth.

[0101] S4. The multi-scale microfiber spunlace fabric is transported to a heat setting machine and heat-set at a temperature of 100° C. for 30 minutes to obtain a dense multi-scale microfiber leather base fabric.

[0102] S5. The surface and interior of the dense multi-scale microfiber leather base fabric are filled with polyurethane by coating or impregnation, with a filling rate of 110%. After drying and shaping, the multi-scale microfiber synthetic leather is obtained.

[0103] Example 3

[0104] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric include the following components in parts by mass:

[0105] 90 parts of ultra-high molecular weight polyethylene with a molecular weight of 200w, 10 parts of high viscosity polyamide 56 with a molecular weight of 7w and a relative viscosity of 3.80, 2000 parts of dichloromethane, and 5 parts of antibacterial silver particles.

[0106] The method for preparing the multi-scale ultrafine fiber synthetic leather of this embodiment comprises the following steps:

[0107] S1. According to the above mass fractions, the raw materials of the spinning solution are mixed to obtain the spinning solution.

[0108] S2. The spinning solution is transferred to a high-temperature and high-pressure reactor with a temperature of 190°C and a pressure of 17MPa, and is ejected from the spinneret through the spinning assembly. The spinning solution is depressurized after being ejected, and the solvent absorbs a large amount of heat and evaporates rapidly to generate a high-speed airflow. At the same time, the polymer is cooled and solidified, and is stretched by the airflow to form a fiber with a diameter of 0.05 to 12.00 μm and a gram weight of 150 g / m on the receiving device. 2 Flash-steamed multi-scale microfiber webs.

[0109] S3. The prepared flash-steamed multi-scale ultrafine fiber web is pre-punched by a low-pressure water jet with a water pressure of 20 MPa, and then passed through a high-pressure water jet with a water pressure of 60 MPa. The multi-scale ultrafine fibers in the flash-steamed multi-scale ultrafine fiber web are entangled with each other by using a high-pressure water jet to obtain a multi-scale ultrafine fiber spunlace cloth.

[0110] S4. The multi-scale microfiber spunlace fabric is transported to a heat setting machine and heat-set for 10 minutes at a temperature of 90° C. to obtain a dense multi-scale microfiber leather base fabric.

[0111] S5. The surface and interior of the dense multi-scale microfiber leather base fabric are filled with polyurethane by coating or impregnation, with a filling rate of 70%. After drying and shaping, the multi-scale microfiber synthetic leather is obtained.

[0112] Example 4

[0113] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric include the following components in parts by mass:

[0114] 50 parts of ultra-high molecular weight polyethylene with a molecular weight of 300w, 50 parts of high viscosity polyamide 6 with a molecular weight of 6w and a relative viscosity of 3.40, 5000 parts of dichloromethane, 1 part of hydrophilic agent polyacrylic acid, 1 part of UV inhibitor titanium dioxide particles, 3 parts of antibacterial agent silver particles, 1 part of flame retardant halogenated phosphate, and 1 part of antistatic agent carbon black.

[0115] The preparation method of the multi-scale ultrafine fiber synthetic leather in this embodiment is the same as that in Embodiment 1, and the filling rate of polyurethane is 125%.

[0116] Example 5

[0117] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric include the following components in parts by mass:

[0118] 95 parts of ultra-high molecular weight polyethylene with a molecular weight of 180w, 5 parts of high viscosity polyamide 6 with a molecular weight of 6w and a relative viscosity of 3.40, 300 parts of dichloromethane, 2 parts of hydrophilic agent polyacrylic acid, 3 parts of UV inhibitor titanium dioxide particles, 2 parts of antibacterial agent silver particles, 2 parts of flame retardant halogenated phosphate, and 3 parts of antistatic agent carbon black.

[0119] The preparation method of the multi-scale ultrafine fiber synthetic leather in this embodiment is the same as that in Embodiment 1, and the filling rate of polyurethane is 50%.

[0120] Example 6

[0121] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the other components and contents of the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric are the same as those in Example 1, except that: 67 parts of ultra-high molecular weight polyethylene with a molecular weight of 180w and 33 parts of high viscosity polyamide 6 with a molecular weight of 6w and a relative viscosity of 3.40, that is, the mass ratio of the two is 2:1.

[0122] The preparation method of the multi-scale ultrafine fiber synthetic leather of this embodiment is the same as that of Example 1.

[0123] Example 7

[0124] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the other components and contents of the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric are the same as those in Example 1, with the difference that: 90 parts of ultra-high molecular weight polyethylene with a molecular weight of 180w and 10 parts of high viscosity polyamide 6 with a molecular weight of 6w and a relative viscosity of 3.40, that is, the mass ratio of the two is 9:1.

[0125] The preparation method of the multi-scale ultrafine fiber synthetic leather of this embodiment is the same as that of Example 1.

[0126] Example 8

[0127] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the other components and contents of the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric are the same as those in Example 1, with the difference that: 50 parts of ultra-high molecular weight polyethylene with a molecular weight of 180w and 50 parts of high viscosity polyamide 6 with a molecular weight of 6w and a relative viscosity of 3.40, that is, the mass ratio of the two is 1:1.

[0128] The preparation method of the multi-scale ultrafine fiber synthetic leather of this embodiment is the same as that of Example 1.

[0129] Example 9

[0130] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the other components and contents of the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric are the same as those in Example 1, with the difference that: 95 parts of ultra-high molecular weight polyethylene with a molecular weight of 180w and 5 parts of high viscosity polyamide 6 with a molecular weight of 6w and a relative viscosity of 3.40, that is, the mass ratio of the two is 19:1.

[0131] The preparation method of the multi-scale ultrafine fiber synthetic leather of this embodiment is the same as that of Example 1.

[0132] Example 10

[0133] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the other components and contents of the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric are the same as those in Example 1, except that the molecular weight of the ultra-high molecular weight polyethylene is 150w. The preparation method of the multi-scale ultrafine fiber synthetic leather of this embodiment is the same as that of Example 1.

[0134] Embodiment 11

[0135] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the other components and contents of the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric are the same as those in Example 1, except that the molecular weight of the ultra-high molecular weight polyethylene is 300w. The preparation method of the multi-scale ultrafine fiber synthetic leather of this embodiment is the same as that of Example 1.

[0136] Example 12

[0137] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the other components and contents of the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric are the same as those in Example 1, except that the molecular weight of the ultra-high molecular weight polyethylene is 100w. The preparation method of the multi-scale ultrafine fiber synthetic leather of this embodiment is the same as that of Example 1.

[0138] Embodiment 13

[0139] In the multi-scale ultrafine fiber synthetic leather of this embodiment, the other components and contents of the raw materials of the spinning solution of the multi-scale ultrafine fiber leather base fabric are the same as those in Example 1, except that the molecular weight of the ultra-high molecular weight polyethylene is 400w. The preparation method of the multi-scale ultrafine fiber synthetic leather of this embodiment is the same as that of Example 1.

[0140] Embodiment 14

[0141] In the multi-scale microfiber synthetic leather of this embodiment, the remaining components and contents of the raw materials of the spinning solution of the multi-scale microfiber leather base fabric are the same as those in Example 1, except that the molecular weight of the high-viscosity polyamide 6 with a relative viscosity of 3.40 is 2w. The preparation method of the multi-scale microfiber synthetic leather of this embodiment is the same as that of Example 1.

[0142] Embodiment 15

[0143] In the multi-scale microfiber synthetic leather of this embodiment, the remaining components and contents of the raw materials of the spinning solution of the multi-scale microfiber leather base fabric are the same as those in Example 1, except that the molecular weight of the high-viscosity polyamide 6 with a relative viscosity of 3.40 is 8w. The preparation method of the multi-scale microfiber synthetic leather of this embodiment is the same as that of Example 1.

[0144] Example 16

[0145] In the multi-scale microfiber synthetic leather of this embodiment, the remaining components and contents of the raw materials of the spinning solution of the multi-scale microfiber leather base fabric are the same as those in Example 1, except that the molecular weight of the high-viscosity polyamide 6 with a relative viscosity of 3.40 is 1w. The preparation method of the multi-scale microfiber synthetic leather of this embodiment is the same as that of Example 1.

[0146] Embodiment 17

[0147] In the multi-scale microfiber synthetic leather of this embodiment, the remaining components and contents of the raw materials of the spinning solution of the multi-scale microfiber leather base fabric are the same as those in Example 1, except that the molecular weight of the high-viscosity polyamide 6 with a relative viscosity of 3.40 is 9w. The preparation method of the multi-scale microfiber synthetic leather of this embodiment is the same as that of Example 1.

[0148] Embodiment 18

[0149] In the multi-scale microfiber synthetic leather of this embodiment, the raw materials and content of the spinning solution of the multi-scale microfiber leather base fabric are the same as those in Example 1. The difference is that in the preparation steps, step S2: the spinning solution is transferred to a high-temperature and high-pressure reactor with a temperature of 150°C and a pressure of 25MPa for flash spinning.

[0150] Embodiment 19

[0151] In the multi-scale microfiber synthetic leather of this embodiment, the raw materials and content of the spinning solution of the multi-scale microfiber leather base fabric are the same as those in Example 1. The difference is that in the preparation steps, step S2: the spinning solution is transferred to a high-temperature and high-pressure reactor with a temperature of 300°C and a pressure of 5MPa for flash spinning.

[0152] Embodiment 20

[0153] In the multi-scale microfiber synthetic leather of this embodiment, the raw materials and content of the spinning solution of the multi-scale microfiber leather base fabric are the same as those in Example 1. The difference is that in the preparation steps, step S2: the spinning solution is transferred to a high-temperature and high-pressure reactor with a temperature of 100°C and a pressure of 30MPa for flash spinning.

[0154] Embodiment 21

[0155] In the multi-scale microfiber synthetic leather of this embodiment, the raw materials and content of the spinning solution of the multi-scale microfiber leather base fabric are the same as those in Example 1. The difference is that in the preparation steps, step S2: the spinning solution is transferred to a high-temperature and high-pressure reactor with a temperature of 400°C and a pressure of 3MPa for flash spinning.

[0156] Embodiment 22

[0157] In the multi-scale ultrafine fiber synthetic leather of the present embodiment, the raw materials and content of the spinning solution of the multi-scale ultrafine fiber leather base cloth are the same as those in Example 1. The difference is that in the preparation step, step S3. The prepared flash-steamed multi-scale ultrafine fiber web is pre-punched by a low-pressure water jet with a water pressure of 20 MPa, and then passed through a high-pressure water jet with a water pressure of 100 MPa. The multi-scale ultrafine fibers in the flash-steamed multi-scale ultrafine fiber web are entangled with each other by using a high-pressure water jet to obtain a multi-scale ultrafine fiber spunlace cloth.

[0158] Embodiment 23

[0159] In the multi-scale ultrafine fiber synthetic leather of the present embodiment, the raw materials and content of the spinning solution of the multi-scale ultrafine fiber leather base cloth are the same as those in Example 1. The difference is that in the preparation step, step S3. The prepared flash-steamed multi-scale ultrafine fiber web is pre-punched by a low-pressure water jet with a water pressure of 35 MPa, and then passed through a high-pressure water jet with a water pressure of 70 MPa. The multi-scale ultrafine fibers in the flash-steamed multi-scale ultrafine fiber web are entangled with each other by using a high-pressure water jet to obtain a multi-scale ultrafine fiber spunlace cloth.

[0160] Embodiment 24

[0161] In the multi-scale ultrafine fiber synthetic leather of the present embodiment, the raw materials and content of the spinning solution of the multi-scale ultrafine fiber leather base fabric are the same as those in Example 1. The difference is that in the preparation step, step S3. The prepared flash-steamed multi-scale ultrafine fiber web is pre-punched by a low-pressure water jet with a water pressure of 20 MPa, and then passed through a high-pressure water jet with a water pressure of 120 MPa. The multi-scale ultrafine fibers in the flash-steamed multi-scale ultrafine fiber web are entangled with each other by using a high-pressure water jet to obtain a multi-scale ultrafine fiber spunlace cloth.

[0162] Embodiment 25

[0163] In the multi-scale ultrafine fiber synthetic leather of the present embodiment, the raw materials and content of the spinning solution of the multi-scale ultrafine fiber leather base cloth are the same as those in Example 1. The difference is that in the preparation step, step S3. The prepared flash-steamed multi-scale ultrafine fiber web is pre-punched by a low-pressure water jet with a water pressure of 50 MPa, and then passed through a high-pressure water jet with a water pressure of 55 MPa. The multi-scale ultrafine fibers in the flash-steamed multi-scale ultrafine fiber web are entangled with each other by using a high-pressure water jet to obtain a multi-scale ultrafine fiber spunlace cloth.

[0164] Embodiment 26

[0165] In the multi-scale microfiber synthetic leather of this embodiment, the raw materials and content of the spinning solution of the multi-scale microfiber leather base fabric are the same as those in Example 1, except that the hydrophilic agent is replaced by polyvinyl alcohol ether.

[0166] Comparative Example 1

[0167] In the ultrafine fiber synthetic leather of this comparative example, the raw materials of the spinning solution of the ultrafine fiber leather base cloth include the following components in parts by mass:

[0168] 80 parts of ultra-high molecular weight polyethylene with a molecular weight of 180w, 1400 parts of dichloromethane, 5 parts of hydrophilic agent polyacrylic acid, 2 parts of anti-ultraviolet agent titanium dioxide particles, 2 parts of antibacterial agent silver particles, 3 parts of flame retardant halogenated phosphate, and 2 parts of antistatic agent carbon black.

[0169] The method for preparing the ultrafine fiber synthetic leather of this comparative example comprises the following steps:

[0170] S1. According to the above mass fractions, the raw materials of the spinning solution are mixed to obtain the spinning solution.

[0171] S2. The spinning solution is transferred to a high-temperature and high-pressure reactor with a temperature of 180°C and a pressure of 15MPa, and is ejected from the spinneret through the spinning assembly. The spinning solution is depressurized after being ejected, and the solvent absorbs a large amount of heat and evaporates rapidly, generating a high-speed airflow. At the same time, the polymer is cooled and solidified, and is stretched by the airflow to form a fiber with a diameter of 1.20-16.00μm and a gram weight of 300g / m on the receiving device. 2 of flash-steamed microfiber mesh.

[0172] S3. The obtained flash-steamed ultrafine fiber web is pre-punched by a low-pressure spunlace head with a water pressure of 30 MPa, and then passed through a high-pressure spunlace head with a water pressure of 90 MPa. The ultrafine fibers in the flash-steamed ultrafine fiber web are entangled with each other by using a high-pressure water jet to obtain an ultrafine fiber spunlace cloth.

[0173] S4. The microfiber spunlace fabric is transported to a heat setting machine and heat-set at 95° C. for 20 minutes to obtain a dense microfiber leather base fabric.

[0174] S5. The surface and interior of the dense microfiber leather base cloth are filled with polyurethane by coating or impregnation, with a filling rate of 100%, and the microfiber synthetic leather is obtained after drying and shaping.

[0175] Comparative Example 2

[0176] In the ultrafine fiber synthetic leather of this comparative example, the raw materials of the spinning solution of the ultrafine fiber leather base cloth include the following components in parts by mass:

[0177] 80 parts of ultra-high molecular weight polyethylene with a molecular weight of 180w, 20 parts of polyethylene terephthalate, 1700 parts of dichloromethane, 5 parts of hydrophilic agent polyacrylic acid, 2 parts of anti-ultraviolet agent titanium dioxide particles, 2 parts of antibacterial agent silver particles, 3 parts of flame retardant halogenated phosphate, and 2 parts of antistatic agent carbon black.

[0178] The method for preparing the ultrafine fiber synthetic leather of this comparative example comprises the following steps:

[0179] S1. According to the above mass fractions, the raw materials of the spinning solution are mixed to obtain the spinning solution.

[0180] S2. The spinning solution is transferred to a high-temperature and high-pressure reactor with a temperature of 180°C and a pressure of 15MPa, and is ejected from the spinneret through the spinning assembly. The spinning solution is depressurized after being ejected, and the solvent absorbs a large amount of heat and evaporates rapidly, generating a high-speed airflow. At the same time, the polymer is cooled and solidified, and is stretched by the airflow to form a fiber with a diameter of 0.10-15.00μm and a gram weight of 300g / m on the receiving device. 2 of flash-steamed microfiber mesh.

[0181] S3. The obtained flash-steamed ultrafine fiber web is pre-punched by a low-pressure spunlace head with a water pressure of 30 MPa, and then passed through a high-pressure spunlace head with a water pressure of 90 MPa. The ultrafine fibers in the flash-steamed ultrafine fiber web are entangled with each other by using a high-pressure water jet to obtain an ultrafine fiber spunlace cloth.

[0182] S4. The microfiber spunlace fabric is transported to a heat setting machine and heat-set at 95° C. for 20 minutes to obtain a dense microfiber leather base fabric.

[0183] S5. The surface and interior of the dense microfiber leather base cloth are filled with polyurethane by coating or impregnation, with a filling rate of 100%, and the microfiber synthetic leather is obtained after drying and shaping.

[0184] like Figure 1-3 This is a scanning electron microscope image of the multi-scale ultrafine fiber synthetic leather prepared in Examples 1-3. It can be seen from the image that the obtained synthetic leather contains overlapping thick and thin fibers, indicating that a multi-scale ultrafine fiber synthetic leather has been formed. Figure 4 , 5 The scanning electron microscope images of the synthetic leather of Comparative Examples 1 and 2 show that the ultrafine fibers in Comparative Examples 1 and 2 have a single scale and do not present a multi-scale effect, and cannot achieve the effect of completely simulating leather collagen fibers.

[0185] The longitudinal and transverse breaking strength and longitudinal and transverse tearing strength of the ultrafine fiber synthetic leather obtained in the above-mentioned embodiments and comparative examples were measured, and the measurement results are shown in Table 1 below. It can be seen from the data in Table 1 that the longitudinal and transverse breaking strength and longitudinal and transverse tearing strength of the multi-scale ultrafine fiber synthetic leather of each embodiment of the present invention are better than those of comparative examples 1 and 2, indicating that the multi-scale ultrafine fiber can greatly improve the mechanical strength performance of the synthetic leather. Among them, compared with Examples 1-5, the mass fractions of the raw materials are different, and Examples 1-3 are preferred embodiments, and their strength performance is better than that of Examples 4 and 5. Compared with Examples 1 and 6-9, the difference is that the mass ratio of ultra-high molecular weight polyethylene to polyamide polymer is different. In comparison, the mass ratio of Examples 1, 6, and 7 is in the preferred range, and the obtained multi-scale ultrafine fiber synthetic leather has better strength performance, indicating that the relative ratio of the thick trunk fiber and the fine branch fiber formed within the mass ratio range is more suitable. Compared with Examples 1 and 10-13, the difference is that the molecular weight of the ultra-high molecular weight polyethylene is different. In comparison, the molecular weight of Examples 1, 10, and 11 is in the preferred range, and the obtained multi-scale ultrafine fiber synthetic leather has better strength performance. Compared with Examples 1, 14-17, the difference is that the molecular weight of the polyamide polymer is different. In comparison, the molecular weight of Examples 1, 14, and 15 is in the preferred range, and the strength performance of the obtained multi-scale ultrafine fiber synthetic leather is better. Compared with Examples 1, 18-21, the difference is that the flash spinning temperature and pressure of step S2 in the preparation method are different. In comparison, the process parameters of Examples 1, 18, and 19 are in the preferred range, and the strength performance of the obtained multi-scale ultrafine fiber synthetic leather is better. Compared with Examples 1, 22-25, the difference is that the pressure in the hydroentanglement solid network of step S3 in the preparation method is different. In comparison, the process parameters of Examples 1, 22, and 23 are in the preferred range, and the strength performance of the obtained multi-scale ultrafine fiber synthetic leather is better. Compared with Example 26, the difference in Example 1 is that the hydrophilic agent is different, and the strength performance of Example 1 is better, indicating that the use of polyacrylic acid as a hydrophilic agent is better.

[0186] Table 1

[0187]

[0188]

[0189] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A multi-scale microfiber leather base fabric, characterized in that: The multi-scale ultrafine fiber leather base fabric is obtained by spinning a spinning solution through a flash evaporation method; the raw materials of the spinning solution include the following components in parts by weight: 50-100 parts of ultra-high molecular weight polyethylene, 0-50 parts of polyamide polymer, and 10-5000 parts of solvent; the mass ratio of ultra-high molecular weight polyethylene to polyamide polymer is 1-20:

1.

2. The multi-scale microfiber leather base fabric according to claim 1, characterized in that: The raw materials of the spinning solution include the following components in parts by weight: 65-90 parts of ultra-high molecular weight polyethylene, 10-35 parts of polyamide polymer, and 500-3000 parts of solvent; the mass ratio of ultra-high molecular weight polyethylene to polyamide polymer is 2-9:

1.

3. The multi-scale microfiber leather base fabric according to claim 1, characterized in that: The molecular weight of the ultra-high molecular weight polyethylene is 150w-300w; the molecular weight of the polyamide polymer is 2w-8w; The polyamide polymer is a mixture of one or more of high viscosity polyamide 6 with a relative viscosity of 3.35-3.45, high viscosity polyamide 66 with a relative viscosity of 4.75-5.35, and high viscosity polyamide 56 with a relative viscosity of 3.00-4.

00.

4. The multi-scale microfiber leather base fabric according to claim 1, characterized in that: The raw materials of the spinning solution also include the following components in parts by weight: 0-5 parts of hydrophilic agent, 0-3 parts of anti-ultraviolet agent, 0-5 parts of antibacterial agent, 0-3 parts of flame retardant, and 0-4 parts of antistatic agent.

5. A method for preparing a multi-scale ultrafine fiber leather base fabric according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. According to the mass fraction, the raw materials of the spinning solution are mixed to obtain a spinning solution; S2. Using the spinning solution, spinning by flash evaporation to obtain a flash multi-scale ultrafine fiber web; S3. The flash-steamed multi-scale ultrafine fiber web is spunlaced to obtain a multi-scale ultrafine fiber spunlaced fabric; S4. heat-setting the multi-scale microfiber spunlace fabric to obtain the multi-scale microfiber leather base fabric.

6. The preparation method according to claim 5, characterized in that: Step S2 specifically includes the following steps: transferring the spinning solution to a high-temperature and high-pressure reactor with a temperature of 100 to 400° C. and a pressure of 3 to 30 MPa, and ejecting the spinning solution from the spinneret through the spinning assembly, releasing the pressure of the spinning solution after ejection, and the solvent absorbing a large amount of heat and evaporating rapidly, thereby generating a high-speed airflow, while the polymer cools and solidifies, and is stretched by the airflow, forming a flash-evaporated multi-scale ultrafine fiber web on the receiving device; Step S3 specifically includes the following steps: pre-piercing the flash-evaporated multi-scale ultrafine fiber web through a low-pressure spunlace head with a water pressure of 20 to 50 MPa, and then passing through a high-pressure spunlace head with a water pressure of 50 to 120 MPa, using a high-pressure water jet to entangle the multi-scale ultrafine fibers in the flash-evaporated multi-scale ultrafine fiber web with each other, thereby obtaining the multi-scale ultrafine fiber spunlace cloth; Step S4 specifically includes the following steps: transporting the multi-scale microfiber spunlace fabric to a heat setting machine, and heat setting it at a temperature of 80 to 110° C. for 3 to 120 minutes to obtain the multi-scale microfiber leather base fabric.

7. The preparation method according to claim 6, characterized in that: In step S2, the temperature of the high temperature and high pressure reactor is 150-300°C and the pressure is 5-25MPa; In step S3, the water pressure of the low-pressure water jet is 20-35 MPa, and the water pressure of the high-pressure water jet is 70-100 MPa; In step S4, the temperature of the heat setting treatment is 90-100° C., and the treatment time is 5-80 minutes.

8. A multi-scale microfiber synthetic leather, characterized in that: It comprises the multi-scale ultra-fine fiber leather base fabric as claimed in any one of claims 1 to 4, wherein the fibers of the multi-scale ultra-fine fiber leather base fabric are filled with polyurethane material.

9. The multi-scale ultrafine fiber synthetic leather according to claim 8, characterized in that: The filling rate of the polyurethane material in the multi-scale ultrafine fiber leather base fabric is 25% to 125%.

10. A method for preparing multi-scale ultrafine fiber synthetic leather as claimed in claim 8, characterized in that: The following steps are involved: The multi-scale superfine fiber leather base cloth is coated or impregnated with polyurethane material on its surface and inside, and then dried and shaped to obtain the multi-scale superfine fiber synthetic leather.

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