Highly moisture-permeable environment-friendly microfiber artificial leather and preparation method thereof

Abstract

The application relates to the technical field of artificial leather preparation, and particularly discloses an environmentally-friendly super-fiber artificial leather with high moisture permeability and a preparation method thereof. The artificial leather comprises, from bottom to top, a high-porosity splitting base cloth, a dot matrix adhesive layer and a gradient porous surface layer. The dot matrix adhesive layer is formed by curing adhesive slurry and comprises a plurality of discrete adhesive points arranged in a periodic array, with through gaps left between the points. The gradient porous surface layer comprises a transition layer and a surface layer, the transition layer is provided with tapered micropores with large top and small bottom, and the surface layer is a microporous structure formed by water evaporation. The preparation method comprises four processes of gradient hydroentanglement splitting, gradient pore-forming coating, dot matrix printing anchoring and heat pressing and bonding curing, and the structure is precisely controlled through gradient temperature control and physical induction. The artificial leather can be applied to the fields of shoemaking, luggage and home interior decoration, can significantly improve the moisture permeability while maintaining the interlayer bonding strength, is produced by using a water-based process, is environmentally friendly in the production process, and has good wear resistance and use feeling.

Description

Technical Field

[0001] This application relates to the field of artificial leather preparation technology, and more specifically, it relates to a highly moisture-permeable and environmentally friendly microfiber artificial leather and its preparation method. Background Technology

[0002] Microfiber synthetic leather possesses a texture and mechanical properties close to natural leather, while also boasting advantages such as abrasion resistance, aging resistance, and uniform material composition. It is widely used in footwear, bags, and home furnishings. With increasing demands for comfort in clothing and the advancement of green transformation in manufacturing, water-based microfiber synthetic leather, combining high moisture permeability and environmental friendliness, is gaining growing attention. It effectively conducts moisture generated during use, improving the contact experience, while its production process requires minimal organic solvents, aligning with the trend towards environmentally friendly manufacturing.

[0003] In current conventional water-based microfiber synthetic leather structures, a continuous, full-width adhesive layer is typically used to bond the base fabric and the surface coating. This continuous adhesive layer creates relatively dense barrier areas between the layers, hindering the vertical transport of moisture and negatively impacting the product's breathability. Attempting to reduce the adhesive area to create moisture channels often results in decreased interlayer adhesion, leading to issues like coating peeling and flaking. This makes it difficult to simultaneously meet the requirements of high breathability and high bonding strength, a critical technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To address the problem that existing microfiber artificial leathers cannot simultaneously achieve good moisture permeability and reliable interlayer bonding strength, this application provides a highly moisture-permeable and environmentally friendly microfiber artificial leather and its preparation method.

[0005] In the first aspect, this application provides a highly moisture-permeable and environmentally friendly microfiber artificial leather, employing the following technical solution: A highly breathable and environmentally friendly microfiber artificial leather comprises, from bottom to top, a high-porosity open-fiber base fabric, a dot matrix bonding layer, and a gradient porous surface layer. The dot matrix adhesive layer is formed by curing an adhesive slurry and includes multiple discrete adhesive dots arranged in a periodic array with through gaps between the dots. The adhesive slurry comprises, by weight: 80 to 85 parts of aliphatic waterborne polyurethane resin, 0.5 to 1 part of γ-ureapropyltriethoxysilane, 0.3 to 0.5 parts of waterborne polyurethane thickener, and 10 to 15 parts of deionized water. The diameter of a single bonding point is 0.3 to 0.5 mm, the center-to-center distance between two adjacent bonding points is 0.8 to 1.2 mm, and the total area of ​​all bonding points accounts for 40% to 50% of the total area of ​​the dot matrix adhesive layer. The gradient porous surface layer comprises a transition layer and a surface layer from bottom to top. The porosity of the transition layer is 35% to 40%, and the surface layer is a microporous structure formed by water evaporation with a porosity of 15% to 20%. The transition layer is formed by curing a transition layer slurry, which comprises, by weight: 60 to 65 parts of waterborne polyurethane resin, 2 to 3 parts of nano-grade hydroxyethyl cellulose, 1 to 2 parts of sodium bicarbonate, 0.5 to 1 part of polyether-modified silicone oil, and 25 to 30 parts of deionized water. The surface layer is formed by curing a surface layer slurry, which comprises, by weight: 70 to 75 parts of waterborne polyurethane resin, 1 to 2 parts of hydrophobic nano silica, 0.5 to 1 part of polyether-modified silicone oil, and 20 to 25 parts of deionized water.

[0006] By adopting the above technical solution, discretely arranged bonding points form a discontinuous bonding region between the base fabric and the gradient porous surface layer. The pre-reserved through gaps between the points constitute vertical water vapor transport channels between layers, breaking the complete blockage of water vapor permeation by traditional continuous bonding layers. The bonding paste uses aliphatic waterborne polyurethane as the main film-forming agent, which has good film-forming properties and hydrolysis resistance. The silane coupling agent can form chemical bonds between the polyurethane resin and the fiber substrate, improving the interfacial adhesion. The waterborne polyurethane thickener is used to adjust the rheological properties of the paste, making the paste suitable for the molding requirements of screen printing, ensuring that the morphology of the bonding points after printing is regular and the edges are clear, and preventing the problem of paste overflow and diffusion, thus ensuring the dimensional accuracy and connectivity of the gaps between the points.

[0007] Preferably, the surface of each bonding point is a dense cured skin with a thickness of 5 to 8 μm, and the cured resin inside the bonding point penetrates into the fiber pores of the base fabric surface to form a fiber interlocking cured structure.

[0008] By adopting the above technical solution, the dense cured skin on the surface of the bonding point can act as a barrier structure during the subsequent hot-pressing process, limiting the lateral flow range of the bonding resin, preventing the slurry from overflowing and clogging the gaps between the points, and maintaining the unobstructed flow of the moisture permeability channels. The viscous resin that is not fully cured inside the bonding point penetrates into the fiber pores of the base fabric surface under the drive of the hot-pressing force. After complete curing, it forms a mechanical interlocking structure in which the resin and fiber interlock. Combined with the chemical bonding effect of the silane coupling agent at the interface, it enhances the bonding strength between the layers, so that the product can still achieve an adhesion strength comparable to a continuous bonding layer even with a lower bonding area ratio.

[0009] Preferably, the micropores of the transition layer have a conical structure with a larger top and a smaller bottom, and the bottom of the micropores is connected to the gap channel of the underlying lattice adhesive layer.

[0010] By adopting the above technical solution, the tapered micropores with a larger top and smaller bottom in the transition layer can guide water vapor to diffuse and be transported gradually from the bottom to the surface. Compared with columnar micropores of the same diameter, the tapered structure has lower water vapor transport resistance and higher diffusion efficiency. The bottom of the micropores is connected to the gap channels of the lattice bonding layer, which can reduce the bending of the water vapor transport path and energy loss caused by pore misalignment. This creates a continuous and interconnected water vapor transport network that extends from the internal pores of the base fabric, through the lattice gap channels, through the tapered micropores of the transition layer, and finally to the micropores of the surface layer. This effectively reduces the resistance of water vapor transmission between layers and improves the overall moisture permeability.

[0011] Preferably, the high-porosity open-fiber base fabric is a needle-punched nonwoven fabric made of island-type sea-island composite fibers opened by hydroentangling coupling, wherein the island component of the sea-island composite fiber is polyethylene terephthalate and the sea component is polyvinyl alcohol; the open-fiber rate is not less than 90%, the residual polyvinyl alcohol content is not higher than 0.5%, and the areal density is 120 to 150 g / m².

[0012] By adopting the above technical solution, the high fiber opening rate of the base fabric has abundant and well-connected inter-fiber pores, which can serve as the bottom layer of water vapor transmission pathways. The low residual amount of marine components can reduce the blockage of inter-fiber pores, ensuring the water vapor conduction efficiency inside the base fabric, while also providing sufficient space for the penetration and integration of bonding resin.

[0013] Secondly, this application provides a method for preparing a highly moisture-permeable and environmentally friendly microfiber artificial leather, employing the following technical solution: A method for preparing a highly moisture-permeable and environmentally friendly microfiber artificial leather includes the following steps: S1. Gradient hydroentanglement fiber opening: Gradient water temperature segmented hydroentanglement fiber opening is performed on the island-type island composite fiber needle-punched nonwoven fabric, and after drying, a high porosity fiber-opened base fabric is obtained. S2, Gradient Pore Coating: A surface layer slurry and a transition layer slurry are sequentially coated on the surface of the carrier, and a gradient porous surface layer is formed in conjunction with a cold fog induction process; S3. Dot matrix printing anchoring: Dot matrix adhesive paste is printed on the surface of the transition layer using screen printing technology, and a carrier with a dot matrix adhesive layer is obtained after semi-curing treatment. S4. Hot-press bonding and curing: The high-porosity open-fiber base fabric is hot-pressed and bonded to a carrier with a dot matrix adhesive layer. After post-curing and cooling, the finished product is obtained.

[0014] By adopting the above technical solution, water-based processes and physical control methods are used throughout the process, without the need for organic solvents. Through step-by-step structural forming and curing control, the base fabric pathway, gradient porous surface layer and lattice adhesive layer are constructed sequentially, achieving synergistic optimization of the breathable structure and bonding performance.

[0015] Preferably, in step S1, the gradient water temperature segmented hydroentangled fiber opening process includes three processing steps: the first and second steps are swelling treatment, with the water temperature controlled at 75 to 78°C, the water needle pressure at 40 to 60 Bar, and the web conveying speed at 25 to 30 m / min; the third to fifth steps are splitting treatment, with the water temperature controlled at 60 to 65°C, the water needle pressure at 90 to 120 Bar, and the web conveying speed consistent with that of the swelling treatment; the sixth and seventh steps are cleaning treatment, with the water temperature controlled at 25 to 30°C and the water needle pressure at 50 to 70 Bar; after the fiber opening is completed, it is dried with hot air at 80 to 85°C for 10 to 15 minutes.

[0016] By adopting the above technical solution, the three-stage gradient water temperature, combined with the corresponding water jet pressure, continuously completes the three processes of swelling, splitting and opening, and residual cleaning of island-island fibers in a single hydroentangling process, eliminating the separate hot water soaking and material transfer steps in traditional processes. The high-temperature stage uses water temperatures adapted to the swelling characteristics of the island-island components, allowing them to fully soften and swell, reducing resistance to subsequent mechanical fiber opening and minimizing breakage damage to the microfibers. The medium-temperature stage, combined with the high-frequency mechanical shearing action of the high-pressure water jet, completes the splitting and opening of the island-island fibers, while simultaneously promoting the peeling and detachment of the swollen island-island components from the fiber surface. The low-temperature stage uses water flow rinsing to remove suspended island-island component debris between fibers, preventing residual substances from clogging fiber pores. The entire process is highly continuous, improving processing efficiency, reducing fiber damage, and lowering the residual amount of island-island components in the base fabric.

[0017] Preferably, in step S3, the dot matrix printing anchor first prepares an adhesive slurry, stirs each component evenly and adjusts the viscosity to 350 to 400 cps, uses a 100-mesh screen to print a periodic circular dot matrix pattern, and then uses infrared vertical irradiation with a wavelength of 5 to 6 μm, with an irradiation power of 8 to 10 kW and an irradiation time of 3 to 5 s.

[0018] By adopting the above technical solution, the viscosity of the adhesive paste is first adjusted to match the process requirements of screen printing, ensuring the printing accuracy of the dot matrix pattern. Then, the surface heating characteristics of infrared radiation are used to make the resin on the surface of the adhesive point undergo cross-linking reaction first, realizing the gradient curing state of the adhesive point being hard on the outside and sticky on the inside. This provides a structural basis for channel blockage prevention and fiber interlocking in the subsequent hot pressing process.

[0019] Preferably, in step S2, the transition layer coating and cold fog-induced pore formation first involves coating the transition layer slurry onto the surface of the surface layer with a coating thickness of 0.10 to 0.12 mm, then uniformly spraying the wet slurry surface with low-pressure, room-temperature deionized water mist at 0.1 to 0.2 MPa at a spraying rate of 5 to 8 g / m², thereby controlling the micropore morphology to form conical micropores with a large top and a small bottom. Subsequently, the pores are dried in stages according to temperature gradients of 90°C, 100°C, and 110°C, with each stage lasting 2 to 3 minutes.

[0020] By employing the above technical solution, low-pressure, room-temperature water mist is uniformly applied to the surface of the wet slurry, forming uniform liquid nucleation sites on the slurry surface. This guides the bubbles generated by the decomposition of the foaming agent to preferentially nucleate and grow at these liquid nucleation sites, resulting in a more uniform pore distribution. Simultaneously, the water mist slows down the curing speed of the surface resin, preventing premature film formation and pore closure, thus ensuring the top opening and connectivity of the conical micropores. Combined with the subsequent gradient heating and drying process, a conical micropore structure with a large top pore diameter and a small bottom pore diameter is ultimately formed. This process can assist in controlling the pore morphology solely through physical induction, and it is environmentally friendly.

[0021] Preferably, in step S2, the surface layer coating first involves applying a surface layer slurry to the surface of the carrier with a coating thickness of 0.05 to 0.08 mm, and then drying it in sections according to a temperature gradient of 100°C, 110°C, and 120°C, with each section remaining for 2 to 3 minutes, to form a gradient structure with a dense surface and internal water-containing volatile micropores.

[0022] By adopting the above technical solution, gradient heating and drying allows the surface resin to form a film and set first, while the internal moisture slowly evaporates to form micropores, thus taking into account both the surface smoothness and wear resistance as well as the ability to dissipate moisture.

[0023] Preferably, in step S4, the hot-press bonding and curing first involves hot-pressing the high-porosity open-fiber base fabric and the carrier with the lattice adhesive layer together at 105 to 115°C and 0.6 to 0.8 MPa for 15 to 20 seconds, then keeping it at 120 to 130°C for 2 to 3 minutes for curing, and finally peeling off the carrier after cooling to room temperature.

[0024] By adopting the above technical solution, the viscous bonding resin is first penetrated into the fiber pores to form an interlocking structure through moderate hot pressing, and then each layer of resin is fully cross-linked and cured through high-temperature insulation, ensuring the stability of the interlayer bonding and the structural integrity.

[0025] In summary, this application has the following beneficial effects: 1. Because this application uses a discretely arranged lattice adhesive layer structure to replace the traditional continuous adhesive layer, and reserves through gaps between the points as channels for water vapor transmission between layers, and at the same time uses infrared semi-curing treatment to form a dense cured skin on the surface of the adhesive points while maintaining a viscous flow state inside, and when hot-pressed, the internal resin penetrates into the pores of the base fabric to form an interlocking structure, the effect of reducing the proportion of adhesive area while maintaining the interfacial bonding strength and significantly improving the moisture permeability is achieved.

[0026] 2. The method of this application uses a gradient water temperature segmented hydroentanglement fiber opening process to couple the three steps of polyvinyl alcohol swelling, fiber splitting and opening, and residual cleaning on the same hydroentanglement production line. By matching the water temperature and water needle pressure parameters at different stages, the fiber opening and weight reduction treatment can be completed in one step, thereby improving production efficiency, reducing fiber damage, and reducing the amount of polyvinyl alcohol residue.

[0027] 3. This application adopts a cold fog-induced surface directional pore-forming process, in which low-pressure, room-temperature deionized water mist is uniformly sprayed onto the surface of the transition layer wet slurry to help control the micropore morphology and form a cone-shaped micropore structure with a large top and a small bottom. The bottom of the micropore is connected to the inter-lattice channel, thus achieving the effect of constructing a through-through moisture-permeable network and reducing the resistance to water vapor transmission.

[0028] 4. As this application adopts a gradient porous surface layer structure, the transition layer has a high porosity to ensure water vapor transmission efficiency, and the surface layer forms a microporous structure through water evaporation and adds hydrophobic nano silica filler, thus achieving the effect of balancing surface wear resistance and water vapor dissipation performance, while optimizing the surface feel. Attached Figure Description

[0029] Figure 1 This is a flowchart of a method for preparing a highly moisture-permeable and environmentally friendly microfiber artificial leather provided in this application; Figure 2 This is a comparison chart of the water vapor permeability test results of the various embodiments and comparative examples provided in this application; Figure 3 This is a comparison diagram of the coating adhesion test results of the various embodiments and comparative examples provided in this application; Figure 4 This is a comparison chart of the wear resistance test results of the various embodiments and comparative examples provided in this application. Detailed Implementation

[0030] The present application will be further described in detail below with reference to embodiments and comparative examples. Unless otherwise specified, the experimental methods used below are conventional methods. Unless otherwise specified, the materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art, which can be obtained by those skilled in the art through commercial channels or prepared according to literature methods.

[0031] Technical Concept: In related technologies, water-based microfiber artificial leather typically uses a full-width continuous adhesive layer to composite the base fabric and surface layer to ensure interlayer bonding strength. This continuous adhesive layer forms a dense barrier, blocking the vertical transport path of moisture between layers, making it difficult to improve the product's moisture permeability. However, if moisture channels are reserved by reducing the bonding area, conventional coating processes cannot accurately control the morphology and rheological state of the bonding area. During hot pressing, the adhesive slurry is prone to lateral overflow, making it difficult to ensure the connectivity of the reserved channels and causing uncontrolled effective bonding area. Ultimately, this results in a significant decrease in interlayer adhesion, failing to simultaneously meet the requirements for high moisture permeability and high bonding strength.

[0032] This application employs a discrete lattice adhesive layer structure design. The size and arrangement of the adhesive dots are precisely controlled through screen printing, with pre-reserved gaps between the dots serving as moisture-permeable channels. Simultaneously, infrared semi-curing treatment creates a dense, cured skin on the surface of the adhesive dots while maintaining a viscous flow state internally. During subsequent hot pressing, the surface layer restricts slurry overflow to maintain channel patency, while the internal resin penetrates the pores of the base fabric fibers to form an interlocking structure, ensuring interlayer bonding strength despite a low adhesive area ratio. A high-porosity base fabric is prepared using a gradient hydroentangling fiber-opening process, and a transition layer with conical micropores is prepared using a cold fog induction process, constructing a fully permeable moisture-permeable network from the base fabric to the surface layer. This significantly improves the product's moisture permeability while ensuring mechanical properties.

[0033] Example 1: This example provides a highly breathable and environmentally friendly microfiber artificial leather, which, from bottom to top, includes a high-porosity open-fiber base fabric, a dot matrix bonding layer, and a gradient porous surface layer.

[0034] The lattice adhesive layer is formed by curing an adhesive slurry and contains multiple discrete adhesive dots arranged in a periodic array, with through gaps between the dots. The adhesive slurry, by weight, comprises: 82.5 parts aliphatic waterborne polyurethane resin, 0.75 parts γ-ureapropyltriethoxysilane, 0.4 parts waterborne polyurethane thickener, and 12.5 parts deionized water. The diameter of a single adhesive dot is 0.4 mm, the center-to-center distance between adjacent adhesive dots is 1.0 mm, and the total area of ​​all adhesive dots accounts for 45% of the total planar area of ​​the lattice adhesive layer.

[0035] The gradient porous surface layer comprises a transition layer and a surface layer from bottom to top. The transition layer has a porosity of 37.5%, while the surface layer is a microporous structure formed by water evaporation with a porosity of 17.5%. The transition layer is formed by curing a transition layer slurry, which, by weight, comprises: 62.5 parts waterborne polyurethane resin, 2.5 parts nano-hydroxyethyl cellulose, 1.5 parts sodium bicarbonate, 0.75 parts polyether-modified silicone oil, and 27.5 parts deionized water. The surface layer is formed by curing a surface layer slurry, which, by weight, comprises: 72.5 parts waterborne polyurethane resin, 1.5 parts hydrophobic nano-silica, 0.75 parts polyether-modified silicone oil, and 22.5 parts deionized water.

[0036] Each bonding point has a dense, cured skin with a thickness of 6.5 μm. The cured resin inside the bonding point penetrates into the fiber pores of the base fabric surface, forming a fiber-intercalated cured structure. The micropores in the transition layer have a conical structure with a larger top and a smaller bottom, and the bottom of the micropores is connected to the gap channels of the underlying lattice bonding layer.

[0037] The high-porosity open-fiber base fabric is a needle-punched nonwoven fabric made of island-type sea-island composite fibers opened by hydroentangling coupling. The island component of the sea-island composite fiber is polyethylene terephthalate and the sea component is polyvinyl alcohol. The fiber opening rate is 95%, the polyvinyl alcohol residue is 0.3%, and the areal density is 135 g / m².

[0038] The preparation method of the above-mentioned highly moisture-permeable and environmentally friendly microfiber artificial leather includes the following steps: S1. Gradient hydroentangling fiber opening: Gradient water temperature segmented hydroentangling coupling fiber opening is performed on island-type island composite fiber needle-punched nonwoven fabric, and high porosity fiber-opened base fabric is obtained after drying.

[0039] The gradient water temperature segmented hydroentangling fiber opening process includes three processing steps: Steps 1 and 2 are swelling treatments, with the water temperature controlled at 76.5℃, the water jet pressure at 50 Bar, and the conveying speed at 27.5 m / min, to fully swell the polyvinyl alcohol sea-island component inside the fiber; Steps 3 to 5 are splitting treatments, with the water temperature controlled at 62.5℃, the water jet pressure at 105 Bar, and the conveying speed consistent with the swelling treatment, to split the island fiber and accelerate the shedding of polyvinyl alcohol through mechanical shearing force; Steps 6 and 7 are cleaning treatments, with the water temperature controlled at 27.5℃ and the water jet pressure at 60 Bar, to rinse away residual polyvinyl alcohol debris between the fibers; After fiber opening, the fiber is dried in hot air at 82.5℃ for 12.5 min.

[0040] S2. Gradient porous coating: A surface layer slurry and a transition layer slurry are sequentially coated on the surface of the carrier, and a gradient porous surface layer is formed in conjunction with a cold fog induction process.

[0041] In the process of surface coating, the surface layer slurry is first applied to the surface of the carrier with a coating thickness of 0.065 mm. It is then dried in sections according to the temperature gradient of 100℃, 110℃ and 120℃, with each section remaining for 2.5 min, to form a gradient structure with a dense surface and internal water-volatile micropores.

[0042] In the process of transition layer coating and cold fog-induced pore formation, the transition layer slurry is first coated on the surface of the surface layer with a coating thickness of 0.11 mm. Low-pressure room temperature deionized water mist of 0.15 MPa is sprayed onto the wet slurry surface through uniformly arranged atomizing nozzles at a spray rate of 6.5 g / m² to control the micropore morphology and form conical micropores with a large top and a small bottom. Then, it is dried in stages according to the temperature gradient of 90℃, 100℃ and 110℃, with each stage lasting for 2.5 min to complete the pore formation and film formation.

[0043] S3. Dot matrix printing anchoring: Dot matrix adhesive paste is printed on the surface of the transition layer using screen printing technology, and a carrier with a dot matrix adhesive layer is obtained after semi-curing treatment.

[0044] The process involves first preparing a bonding slurry, adding all components to a mixing tank, and stirring at 300 r / min for 20 min. After thorough mixing, the viscosity is adjusted to 375 cps. A periodic circular dot matrix pattern is then printed using a 100-mesh screen. Next, the dot matrix area is irradiated with a vertical uniform scanning infrared light with a wavelength of 5.5 μm at a scanning rate of 5 m / min, an irradiation power of 9 kW, and an irradiation time of 4 s. This process ensures that a dense, solidified skin forms on the surface of the bonding points while maintaining a viscous flow state inside.

[0045] S4. Hot-press bonding and curing: The high-porosity open-fiber base fabric is hot-pressed and bonded to a carrier with a dot matrix adhesive layer. After post-curing and cooling, the finished product is obtained.

[0046] The process involves first hot-pressing a high-porosity open-fiber base fabric and a carrier with a dot matrix adhesive layer at 110℃ and 0.7MPa for 17.5s using a roller press, allowing the viscous resin inside the adhesive points to penetrate into the fiber pores of the base fabric; then, the fabric is kept at 125℃ for 2.5min to allow the resin layers to fully cross-link; and finally, the carrier is peeled off after cooling to room temperature.

[0047] Example 2: This example provides a highly breathable and environmentally friendly microfiber artificial leather, which, from bottom to top, includes a high-porosity open-fiber base fabric, a dot matrix bonding layer, and a gradient porous surface layer.

[0048] The lattice adhesive layer is formed by curing an adhesive slurry and contains multiple discrete adhesive dots arranged in a periodic array, with through gaps between the dots. The adhesive slurry, by weight, comprises: 80 parts aliphatic waterborne polyurethane resin, 0.5 parts γ-ureapropyltriethoxysilane, 0.3 parts waterborne polyurethane thickener, and 10 parts deionized water. The diameter of a single adhesive dot is 0.3 mm, the center-to-center distance between adjacent adhesive dots is 0.8 mm, and the total area of ​​all adhesive dots accounts for 40% of the total planar area of ​​the lattice adhesive layer.

[0049] The gradient porous surface layer comprises a transition layer and a surface layer from bottom to top. The transition layer has a porosity of 35%, while the surface layer is a microporous structure formed by water evaporation with a porosity of 15%. The transition layer is formed by curing a transition layer slurry, which, by weight, comprises: 60 parts waterborne polyurethane resin, 2 parts nano-hydroxyethyl cellulose, 1 part sodium bicarbonate, 0.5 parts polyether-modified silicone oil, and 25 parts deionized water. The surface layer is formed by curing a surface layer slurry, which, by weight, comprises: 70 parts waterborne polyurethane resin, 1 part hydrophobic nano-silica, 0.5 parts polyether-modified silicone oil, and 20 parts deionized water.

[0050] Each bonding point has a dense, cured skin with a thickness of 5 μm. The cured resin inside the bonding point penetrates into the fiber pores of the base fabric surface, forming a fiber-intercalated cured structure. The micropores in the transition layer have a conical structure with a larger top and a smaller bottom, and the bottom of the micropores is connected to the gap channels of the underlying lattice bonding layer.

[0051] The high-porosity open-fiber base fabric is a needle-punched nonwoven fabric made of island-type sea-island composite fibers opened by hydroentangling coupling. The island component of the sea-island composite fiber is polyethylene terephthalate and the sea component is polyvinyl alcohol. The fiber opening rate is 90%, the polyvinyl alcohol residue is 0.5%, and the areal density is 120g / m².

[0052] The preparation method of the above-mentioned highly moisture-permeable and environmentally friendly microfiber artificial leather includes the following steps: S1. Gradient hydroentangling fiber opening: Gradient water temperature segmented hydroentangling coupling fiber opening is performed on island-type island composite fiber needle-punched nonwoven fabric, and high porosity fiber-opened base fabric is obtained after drying.

[0053] The gradient water temperature segmented hydroentangling coupling fiber opening process includes three processing steps: Steps 1 and 2 are swelling treatments, with the water temperature controlled at 75℃, the water jet pressure at 40 Bar, and the conveying speed at 25 m / min, to fully swell the polyvinyl alcohol sea-island component inside the fiber; Steps 3 to 5 are splitting treatments, with the water temperature controlled at 60℃, the water jet pressure at 90 Bar, and the conveying speed consistent with the swelling treatment, to split and open the island-island fiber through mechanical shearing force and accelerate the shedding of polyvinyl alcohol; Steps 6 and 7 are cleaning treatments, with the water temperature controlled at 25℃ and the water jet pressure at 50 Bar, to rinse away residual polyvinyl alcohol debris between the fibers; After fiber opening, the fiber is dried in hot air at 80℃ for 10 minutes.

[0054] S2. Gradient porous coating: A surface layer slurry and a transition layer slurry are sequentially coated on the surface of the carrier, and a gradient porous surface layer is formed in conjunction with a cold fog induction process.

[0055] In the process of surface coating, the surface layer slurry is first applied to the surface of the carrier with a coating thickness of 0.05 mm. The surface is then dried in sections at temperature gradients of 100℃, 110℃, and 120℃, with each section remaining for 2 minutes, to form a gradient structure with a dense surface and internal water-volatile micropores.

[0056] In the process of transition layer coating and cold fog-induced pore formation, the transition layer slurry is first coated on the surface of the surface layer with a coating thickness of 0.10 mm. Low-pressure room temperature deionized water mist of 0.1 MPa is sprayed onto the wet slurry surface through uniformly arranged atomizing nozzles at a spraying rate of 5 g / m² to control the micropore morphology and form conical micropores with a large top and a small bottom. Then, it is dried in sections according to the temperature gradient of 90℃, 100℃ and 110℃, with each section staying for 2 minutes to complete the pore formation and film formation.

[0057] S3. Dot matrix printing anchoring: Dot matrix adhesive paste is printed on the surface of the transition layer using screen printing technology, and a carrier with a dot matrix adhesive layer is obtained after semi-curing treatment.

[0058] The process involves first preparing a bonding slurry, adding all components to a mixing tank, and stirring at 250 r / min for 15 min. After thorough mixing, the viscosity is adjusted to 350 cps. A periodic circular dot matrix pattern is then printed using a 100-mesh screen. Next, the dot matrix area is irradiated with a vertical uniform scanning infrared light with a wavelength of 5 μm at a scanning rate of 6 m / min, an irradiation power of 8 kW, and an irradiation time of 3 s. This process ensures that a dense, solidified skin forms on the surface of the bonding points while maintaining a viscous flow state inside.

[0059] S4. Hot-press bonding and curing: The high-porosity open-fiber base fabric is hot-pressed and bonded to a carrier with a dot matrix adhesive layer. After post-curing and cooling, the finished product is obtained.

[0060] The process involves first hot-pressing a high-porosity open-fiber base fabric and a carrier with a dot matrix adhesive layer at 105℃ and 0.6MPa for 15 seconds using a roller press, allowing the viscous resin inside the adhesive points to penetrate into the fiber pores of the base fabric; then, it is kept at 120℃ for 2 minutes to cure, allowing the resin in each layer to fully cross-link; and finally, the carrier is peeled off after cooling to room temperature.

[0061] Example 3: This example provides a highly breathable and environmentally friendly microfiber artificial leather, which, from bottom to top, includes a high-porosity open-fiber base fabric, a dot matrix bonding layer, and a gradient porous surface layer.

[0062] The lattice adhesive layer is formed by curing an adhesive slurry and contains multiple discrete adhesive dots arranged in a periodic array, with through gaps between the dots. The adhesive slurry, by weight, comprises: 85 parts aliphatic waterborne polyurethane resin, 1 part γ-ureapropyltriethoxysilane, 0.5 parts waterborne polyurethane thickener, and 15 parts deionized water. The diameter of a single adhesive dot is 0.5 mm, the center-to-center distance between adjacent adhesive dots is 1.2 mm, and the total area of ​​all adhesive dots accounts for 50% of the total planar area of ​​the lattice adhesive layer.

[0063] The gradient porous surface layer comprises a transition layer and a surface layer from bottom to top. The transition layer has a porosity of 40%, while the surface layer is a microporous structure formed by water evaporation with a porosity of 20%. The transition layer is formed by curing a transition layer slurry, which, by weight, comprises: 65 parts waterborne polyurethane resin, 3 parts nano-hydroxyethyl cellulose, 2 parts sodium bicarbonate, 1 part polyether-modified silicone oil, and 30 parts deionized water. The surface layer is formed by curing a surface layer slurry, which, by weight, comprises: 75 parts waterborne polyurethane resin, 2 parts hydrophobic nano-silica, 1 part polyether-modified silicone oil, and 25 parts deionized water.

[0064] Each bonding point has a dense, cured skin with a thickness of 8 μm. The cured resin inside the bonding point penetrates into the fiber pores of the base fabric surface, forming a fiber-intercalated cured structure. The micropores in the transition layer have a conical structure with a larger top and a smaller bottom, and the bottom of the micropores is connected to the gap channels of the underlying lattice bonding layer.

[0065] The high-porosity open-fiber base fabric is a needle-punched nonwoven fabric made of island-type sea-island composite fibers opened by hydroentangling coupling. The island component of the sea-island composite fiber is polyethylene terephthalate and the sea component is polyvinyl alcohol. The fiber opening rate is 98%, the polyvinyl alcohol residue is 0.2%, and the areal density is 150 g / m².

[0066] The preparation method of the above-mentioned highly moisture-permeable and environmentally friendly microfiber artificial leather includes the following steps: S1. Gradient hydroentangling fiber opening: Gradient water temperature segmented hydroentangling coupling fiber opening is performed on island-type island composite fiber needle-punched nonwoven fabric, and high porosity fiber-opened base fabric is obtained after drying.

[0067] The gradient water temperature segmented hydroentangling coupling fiber opening process includes three processing steps: Steps 1 and 2 are swelling treatments, with the water temperature controlled at 78℃, the water jet pressure at 60 Bar, and the web conveying speed at 30 m / min, to fully swell the polyvinyl alcohol sea-island component inside the fiber; Steps 3 to 5 are splitting treatments, with the water temperature controlled at 65℃, the water jet pressure at 120 Bar, and the web conveying speed consistent with the swelling treatment, to split and open the island-island fiber through mechanical shearing force and accelerate the shedding of polyvinyl alcohol; Steps 6 and 7 are cleaning treatments, with the water temperature controlled at 30℃ and the water jet pressure at 70 Bar, to rinse away residual polyvinyl alcohol debris between the fibers; After fiber opening, the fiber is dried in hot air at 85℃ for 15 min.

[0068] S2. Gradient porous coating: A surface layer slurry and a transition layer slurry are sequentially coated on the surface of the carrier, and a gradient porous surface layer is formed in conjunction with a cold fog induction process.

[0069] In the process of surface coating, the surface layer slurry is first applied to the surface of the carrier with a coating thickness of 0.08 mm. The surface is then dried in sections at temperature gradients of 100℃, 110℃, and 120℃, with each section remaining for 3 minutes, to form a gradient structure with a dense surface and internal water-volatile micropores.

[0070] In the process of transition layer coating and cold fog-induced pore formation, the transition layer slurry is first coated on the surface of the surface layer with a coating thickness of 0.12 mm. Low-pressure room temperature deionized water mist of 0.2 MPa is sprayed onto the wet slurry surface through uniformly arranged atomizing nozzles at a spraying rate of 8 g / m² to control the micropore morphology and form conical micropores with a large top and a small bottom. Then, it is dried in stages according to the temperature gradient of 90℃, 100℃ and 110℃, with each stage lasting for 3 minutes to complete the pore formation and film formation.

[0071] S3. Dot matrix printing anchoring: Dot matrix adhesive paste is printed on the surface of the transition layer using screen printing technology, and a carrier with a dot matrix adhesive layer is obtained after semi-curing treatment.

[0072] The process involves first preparing a bonding slurry, adding all components to a mixing tank, and stirring at 350 r / min for 25 min until homogeneous. The viscosity is then adjusted to 400 cps. A periodic circular dot matrix pattern is printed using a 100-mesh screen. The dot matrix area is then irradiated with a vertical uniform infrared scan at a wavelength of 6 μm, a scanning rate of 4 m / min, an irradiation power of 10 kW, and an irradiation time of 5 s. This process ensures that a dense, solidified skin forms on the surface of the bonding points while maintaining a viscous flow state inside.

[0073] S4. Hot-press bonding and curing: The high-porosity open-fiber base fabric is hot-pressed and bonded to a carrier with a dot matrix adhesive layer. After post-curing and cooling, the finished product is obtained.

[0074] The process involves first hot-pressing a high-porosity open-fiber base fabric and a carrier with a dot matrix adhesive layer at 115℃ and 0.8MPa for 20 seconds using a roller press, allowing the viscous resin inside the adhesive points to penetrate into the fiber pores of the base fabric; then curing at 130℃ for 3 minutes to ensure complete cross-linking of the resin layers; and finally peeling off the carrier after cooling to room temperature.

[0075] Comparative Example 1: The only difference between this comparative example and Example 1 is that: in step S3, the whole-surface scraping process is used instead of the screen printing dot matrix process, the adhesive paste formula and total coating thickness are the same as in Example 1, the bonding area ratio is 100%, there is no through gap structure between dots, and the remaining raw material ratios, process steps and parameters are completely the same as in Example 1.

[0076] Comparative Example 2: The only difference between this comparative example and Example 1 is that after screen printing the adhesive paste in step S3, it is not subjected to infrared irradiation semi-curing treatment and directly enters the subsequent hot pressing bonding process. The remaining raw material ratios, process steps and parameters are completely consistent with Example 1.

[0077] Comparative Example 3: The only difference between this comparative example and Example 1 is that after the transition layer slurry is applied in step S2, low-pressure room temperature deionized water mist is not sprayed, and gradient drying is carried out directly to form holes. The other raw material ratios, process steps and parameters are completely consistent with Example 1.

[0078] Comparative Example 4: The only difference between this comparative example and Example 1 is that: in step S1, all hydroentangling passes use 60°C constant temperature water, and there is no temperature gradient between the 75~78°C swelling section and the 25~30°C cleaning section. The remaining water needle pressure, wire conveying speed and subsequent process parameters are completely consistent with Example 1.

[0079] Comparative Example 5: The only difference between this comparative example and Example 1 is that it is prepared using a conventional DMF wet impregnation-toluene reduction process. Specifically, the microfiber nonwoven fabric is impregnated with DMF-type polyurethane, formed by DMF aqueous solution coagulation bath, reduced by toluene extraction, and dry lamination. The hydroentanglement fiber opening, dot matrix bonding, and cold fogging pore formation processes of this application are not used. The other basic specifications such as product width and thickness are the same as those of Example 1.

[0080] I. Water vapor permeability test, test standard: GB / T39369-2020 "Physical and Mechanical Tests for Leather: Determination of Water Vapor Permeability"; Circular specimens with a diameter of 70 mm were cut from the samples prepared in Examples 1 to 3 and Comparative Examples 1 to 5. Three parallel specimens were prepared for each sample. The test was conducted using a water vapor permeability tester. The test environment parameters were set as follows: temperature 38℃, relative humidity 50%, air velocity 0.5 m / s. The test operation was strictly performed according to the procedure specified in GB / T39369-2020. 30 mL of deionized water was added to a clean and dry moisture permeation cup. The base fabric side of the specimen was placed facing the inside of the moisture permeation cup, and the gradient porous surface layer was facing the outside. In the test environment, the edge of the permeable cup was sealed with a sealing gasket to ensure that the sample and the cup mouth were in close contact without gaps. The assembled permeable cup was placed on a horizontal support in the constant temperature and humidity test chamber and allowed to stand for 1 hour to reach equilibrium. Then, the cup was removed and weighed using an analytical balance with an accuracy of 0.1 mg. After weighing, the permeable cup was returned to the test chamber. The cup was then weighed every 2 hours for a total of 3 times. The total mass value of each weighing was recorded. The permeable water vapor per unit area per unit time was calculated based on the mass difference between two consecutive weighings. The mass change of the blank test was deducted during the calculation. The arithmetic mean of the test results of 3 parallel samples was taken as the final permeable water vapor performance value of the sample.

[0081] II. Coating Adhesion Fastness Test, Test Standard: GB / T39452-2020 "Physical and Mechanical Testing of Leather - Determination of Coating Adhesion Fastness"; Strip specimens with a length of 150 mm and a width of 20 mm were cut from the samples prepared in Examples 1 to 3 and Comparative Examples 1 to 5. Three parallel specimens were prepared for each sample. The specimens were cut along the warp direction to ensure that the direction of force was consistent with the fiber arrangement direction. The test was conducted using a computer-controlled universal testing machine under standard atmospheric conditions: an ambient temperature of 23℃ and a relative humidity of 50%. The test operation was strictly performed according to the procedures specified in GB / T39452-2020. A 20 mm incision was made at one end of the coating of the specimen with a sharp blade. A long transverse slit is made to peel the gradient porous surface layer and the high-porosity open-fiber base fabric apart along the slit to form a free end. The coating side and the base fabric side of the free end are clamped in the upper and lower clamps of the universal testing machine, respectively. The clamp spacing is adjusted to 100 mm to ensure that the force axis of the sample coincides with the tensile direction. The tensile speed of the testing machine is set to 100 mm / min. The testing machine is started to perform a 180° peel test. The curve of force value changing with displacement during the peel process is recorded. The data of the initial clamping section and the end fracture section are discarded. The average force value of the middle effective peel section is taken. The coating adhesion strength per unit width is calculated in combination with the sample width. The arithmetic mean of the test results of 3 parallel samples is taken as the final coating adhesion strength value of the sample.

[0082] III. Abrasion Resistance Test, Test Standard: GB / T21196.2-2007, "Textiles - Martindale Method: Determination of Abrasion Resistance of Fabrics - Part 2: Determination of Specimen Breakage". Circular specimens with a diameter of 38 mm were cut from the samples prepared in Examples 1 to 3 and Comparative Examples 1 to 5. Three parallel specimens were prepared for each sample. The test was conducted using a Martindale abrasion tester, with a test pressure set to 9 kPa. Wool felt conforming to the standard was used as the abrasive. The test environment temperature was 23℃, and the relative humidity was 50%. The test operation strictly followed GB / T21196.2-2007. Follow the procedure specified in 07. Fix the sample with the coated side facing up on the sample holder. Fix the abrasive in the fixture of the grinding table. Adjust the relative position of the sample holder and the grinding table to ensure uniform contact between the sample and the abrasive during the friction process. Start the testing instrument to begin the reciprocating friction test. Stop the machine once every 1,000 friction cycles. Visually observe the state of the coating on the sample surface and record the total number of friction cycles until the sample coating is damaged and the base fabric is exposed. If the sample is still not damaged after 20,000 friction cycles, terminate the test and record the number of friction cycles. Take the arithmetic mean of the test results of 3 parallel samples as the final wear resistance value of the sample.

[0083] Table 1: Test results of sample performance in each embodiment and comparative example As can be seen from Examples 1-3 and Comparative Example 1 and Table 1, the use of a continuous adhesive layer structure blocks the interlayer moisture transport path, resulting in a significant decrease in moisture permeability. However, the increase in adhesive area does not significantly increase the interfacial bonding strength, which fully demonstrates the technical role of discrete lattice adhesive structure in effectively opening up interlayer moisture permeability channels while maintaining interfacial bonding strength.

[0084] Based on Examples 1-3 and Comparative Example 2, and in conjunction with Table 1, it can be seen that when infrared semi-curing anchoring treatment is lacking, the adhesive slurry is prone to lateral overflow during subsequent hot pressing, causing the moisture permeability channels between points to be blocked. At the same time, the internal viscous resin cannot fully penetrate into the pores of the base fabric fiber to form an interlocking structure, and the interfacial bonding strength is also reduced accordingly.

[0085] As can be seen from Examples 1-3 and Comparative Example 3, and Table 1, after the cold fog-induced pore-forming process is cancelled, the transition layer cannot form a directionally arranged conical micropore structure. The spatial permeability between the micropores and the gaps in the lattice below decreases, the resistance of the water vapor transport path increases, and the moisture permeability is significantly reduced. However, the interfacial bonding strength and surface wear resistance are not significantly affected.

[0086] As can be seen from Examples 1-3 and Comparative Example 4 and Table 1, when the constant temperature hydroentangling fiber opening process is used, the marine components in the fiber cannot fully swell and fall off, the fiber opening rate of the base fabric decreases and the residual components are too high, the porosity between fibers decreases, which not only affects the transmission efficiency of water vapor inside the base fabric, but also hinders the penetration of the bonding resin to form a fiber interlocking structure, and the interfacial bonding strength is also affected.

[0087] Based on Examples 1-3 and Comparative Example 5, and in conjunction with Table 1, it can be seen that the samples prepared using the traditional solvent-based process have a dense overall coating structure with poor internal pore connectivity, resulting in greater resistance to water vapor permeation. Furthermore, the degree of fiber opening in the base fabric and the interface bonding method differ from those of this scheme. Overall, the moisture permeability and surface abrasion resistance are lower than those of the samples prepared using the water-based process of this scheme.

[0088] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A highly breathable and environmentally friendly microfiber artificial leather, characterized in that: From bottom to top, it includes a high-porosity open-fiber base fabric, a lattice bonding layer, and a gradient porous surface layer; The dot matrix adhesive layer is formed by curing adhesive slurry and contains multiple discrete adhesive points arranged in a periodic array with through gaps between the points. The adhesive slurry comprises, by weight: 80 to 85 parts aliphatic waterborne polyurethane resin, 0.5 to 1 part γ-ureapropyltriethoxysilane, 0.3 to 0.5 parts waterborne polyurethane thickener, and 10 to 15 parts deionized water; The diameter of a single bonding point is 0.3 to 0.5 mm, the center-to-center distance between two adjacent bonding points is 0.8 to 1.2 mm, and the total area of ​​all bonding points accounts for 40% to 50% of the total area of ​​the dot matrix adhesive layer. The gradient porous surface layer comprises a transition layer and a surface layer from bottom to top. The porosity of the transition layer is 35% to 40%, and the surface layer is a microporous structure formed by water evaporation with a porosity of 15% to 20%. The transition layer is formed by curing a transition layer slurry, which comprises, by weight: 60 to 65 parts of waterborne polyurethane resin, 2 to 3 parts of nano-grade hydroxyethyl cellulose, 1 to 2 parts of sodium bicarbonate, 0.5 to 1 part of polyether-modified silicone oil, and 25 to 30 parts of deionized water. The surface layer is formed by curing a surface layer slurry, which comprises, by weight: 70 to 75 parts of waterborne polyurethane resin, 1 to 2 parts of hydrophobic nano silica, 0.5 to 1 part of polyether-modified silicone oil, and 20 to 25 parts of deionized water.

2. The highly breathable and environmentally friendly microfiber artificial leather according to claim 1, characterized in that: The surface of each bonding point is a dense cured skin with a thickness of 5 to 8 μm. The cured resin inside the bonding point penetrates into the fiber pores of the base fabric surface to form a fiber interlocking cured structure.

3. The highly breathable and environmentally friendly microfiber artificial leather according to claim 1, characterized in that: The micropores in the transition layer have a conical structure with a larger top and a smaller bottom, and the bottom of the micropores is connected to the gap channel of the lattice adhesive layer below.

4. The highly breathable and environmentally friendly microfiber artificial leather according to claim 1, characterized in that: The high-porosity open-fiber base fabric is a needle-punched nonwoven fabric made of island-type sea-island composite fibers through hydroentangling coupling. The island component of the sea-island composite fiber is polyethylene terephthalate and the sea component is polyvinyl alcohol. The open-fiber rate is not less than 90%, the residual polyvinyl alcohol content is not higher than 0.5%, and the areal density is 120 to 150 g / m².

5. A method for preparing a highly moisture-permeable and environmentally friendly microfiber artificial leather, characterized in that, The preparation of the highly moisture-permeable and environmentally friendly microfiber artificial leather according to any one of claims 1 to 4 includes the following steps: S1. Gradient hydroentanglement fiber opening: Gradient water temperature segmented hydroentanglement fiber opening is performed on the island-type island composite fiber needle-punched nonwoven fabric, and after drying, a high porosity fiber-opened base fabric is obtained. S2, Gradient Pore Coating: A surface layer slurry and a transition layer slurry are sequentially coated on the surface of the carrier, and a gradient porous surface layer is formed in conjunction with a cold fog induction process; S3. Dot matrix printing anchoring: Dot matrix adhesive paste is printed on the surface of the transition layer using screen printing technology, and a carrier with a dot matrix adhesive layer is obtained after semi-curing treatment. S4. Hot-press bonding and curing: The high-porosity open-fiber base fabric is hot-pressed and bonded to a carrier with a dot matrix adhesive layer. After post-curing and cooling, the finished product is obtained.

6. The method for preparing a highly moisture-permeable and environmentally friendly microfiber artificial leather according to claim 5, characterized in that: In step S1, the gradient water temperature segmented hydroentangled fiber opening process includes three processing steps: the first two steps are swelling treatment, with the water temperature controlled at 75 to 78°C, the water needle pressure at 40 to 60 Bar, and the fiber conveying speed at 25 to 30 m / min; the third to fifth steps are splitting treatment, with the water temperature controlled at 60 to 65°C, the water needle pressure at 90 to 120 Bar, and the fiber conveying speed consistent with that of the swelling treatment; the sixth and seventh steps are cleaning treatment, with the water temperature controlled at 25 to 30°C and the water needle pressure at 50 to 70 Bar. After fiber opening, dry with hot air at 80 to 85°C for 10 to 15 minutes.

7. The method for preparing a highly moisture-permeable and environmentally friendly microfiber artificial leather according to claim 5, characterized in that: In step S3, the dot matrix printing anchor first prepares the adhesive paste, stirs each component evenly and adjusts the viscosity to 350 to 400 cps, uses a 100-mesh screen to print periodic circular dot matrix patterns, and then uses infrared vertical irradiation with a wavelength of 5 to 6 μm to irradiate the dot matrix area with an irradiation power of 8 to 10 kW and an irradiation time of 3 to 5 s.

8. The method for preparing a highly moisture-permeable and environmentally friendly microfiber artificial leather according to claim 5, characterized in that: In step S2, the transition layer coating and cold fog-induced pore formation first involves coating the transition layer slurry onto the surface of the surface layer with a coating thickness of 0.10 to 0.12 mm. Then, a low-pressure, room-temperature deionized water mist of 0.1 to 0.2 MPa is uniformly sprayed onto the wet slurry surface at a spraying rate of 5 to 8 g / m² to control the micropore morphology and form conical micropores with a large top and a small bottom. Subsequently, the micropores are dried in stages according to a temperature gradient of 90°C, 100°C, and 110°C, with each stage lasting 2 to 3 minutes.

9. The method for preparing a highly moisture-permeable and environmentally friendly microfiber artificial leather according to claim 5, characterized in that: In step S2, the surface layer coating first involves applying a surface layer slurry to the surface of the carrier with a coating thickness of 0.05 to 0.08 mm. The slurry is then dried in sections at temperature gradients of 100°C, 110°C, and 120°C, with each section remaining for 2 to 3 minutes to form a gradient structure with a dense surface and internal water-volatile micropores.

10. The method for preparing a highly moisture-permeable and environmentally friendly microfiber artificial leather according to claim 5, characterized in that: In step S4, the hot-press bonding and curing first involves hot-pressing the high-porosity open-fiber base fabric and the carrier with the lattice adhesive layer together at 105 to 115°C and 0.6 to 0.8 MPa for 15 to 20 seconds, then keeping it at 120 to 130°C for 2 to 3 minutes for curing, and finally peeling off the carrier after cooling to room temperature.

Images