Electrical functional leather as well as preparation method and application thereof

Abstract

The invention relates to the technical field of functional leather materials, in particular to electrical functional leather as well as a preparation method and application thereof. The leather with the electrical function comprises a leather base material, the bottom coating layer is formed on at least one surface of the leather base material; the functional layer is formed on the bottom coating layer and comprises a hybrid conductive network formed by mutually combining a conductive polymer and an inorganic nano material; and the protective layer is formed on the surface of the functional layer. According to the electrical functional leather, on the premise that a small amount of inorganic nano materials are added and the inherent performance of the leather is not affected, a stable, efficient and patterned conductive network is constructed, the leather is endowed with excellent electrical performance, and the application range of the leather in the fields of intelligent wearing, electromagnetic protection and the like is widened.

Description

Technical Field

[0001] This invention relates to the field of functional leather materials technology, and more specifically, to an electrically functional leather, its preparation method, and its application. Background Technology

[0002] Traditional leather, with its excellent breathability, flexibility, and durability, has been widely used in clothing, footwear, bags, furniture, and other fields. However, with the advancement of technology and social development, people have placed higher demands on the performance of leather materials. Not only do they need to maintain their original excellent properties, but they also need to possess electrical properties to meet the needs of emerging fields such as smart wearables and electromagnetic protection.

[0003] Current research on conductive leather has made some progress, but existing preparation methods have many problems. For example, existing technologies (CN113196419A, CN119061212B) use metal foil lamination or highly filled carbon black resin to impart conductivity to leather; however, this method results in stiff leather, poor breathability, unstable resistance, and easy delamination. Existing technology (CN116804235A) directly coats leather with a conductive polymer solution, but due to the porous structure of the leather, the solution easily permeates and leaks, leading to low conductivity and poor abrasion resistance. Nanomaterials (such as carbon nanotubes and silver nanowires) are unevenly dispersed in the resin, usually requiring high addition levels (>10wt%) to achieve conductivity, which not only increases cost but also degrades the mechanical properties of the leather.

[0004] Therefore, how to construct a stable, efficient, and patternable conductive network with low additive content and without affecting the inherent properties of leather (softness and breathability) has become a pressing technical challenge in the field of functional leather materials.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The present invention aims to overcome the problems of existing conductive leather, such as stiff feel, poor breathability, unstable resistance, easy delamination, high cost, and deterioration of mechanical properties, and provides an electrically functional leather, its preparation method and application.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: An electrically functional leather, comprising: Leather substrate; A base coating formed on at least one surface of the leather substrate; A functional layer is formed on the base coating, the functional layer comprising a hybrid conductive network formed by the combination of conductive polymer and inorganic nanomaterials; And a protective layer formed on the surface of the functional layer.

[0008] Preferably, the conductive polymer comprises at least one of poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, polypyrrole, polyaniline, or poly(3,4-ethylenedioxythiophene).

[0009] Preferably, the inorganic nanomaterial includes at least one of silver nanowires, carbon nanotubes, graphene, carbon fibers, or Mxene.

[0010] Preferably, the thickness of the functional layer is ≤20μm and the surface resistivity is 10. 2 ~10 3 Ω / sq.

[0011] Preferably, the functional layer is mainly made of a functional layer solution coated on the base layer.

[0012] Preferably, the functional layer solution comprises: 15wt% to 45wt% of the conductive polymer, 1wt% to 10wt% of the inorganic nanomaterial, and the balance being an aqueous polyurethane solution.

[0013] Preferably, the functional layer solution further comprises 0.5wt% to 2wt% of a crosslinking agent.

[0014] Preferably, the crosslinking agent includes at least one of the following: polycarbodiimide, aziridine, carbodiimide, epoxy resin, oxazoline, polyfunctional aziridine, melamine resin, or organosilicon.

[0015] Preferably, the material of the base coating includes: cationic modified polyurethane.

[0016] Preferably, the thickness of the base coating is 3~8μm.

[0017] Preferably, the material of the protective layer includes: fluorinated silicone-modified transparent polyurethane.

[0018] Preferably, the thickness of the protective layer is 2~5μm.

[0019] A method for preparing the aforementioned electrically functional leather includes the following steps: (a) Forming a base coating on at least one surface of a leather substrate; (b) After coating the base layer with a functional layer solution, perform annealing to obtain a functional layer; The functional layer solution comprises: a conductive polymer and inorganic nanomaterials; (c) A protective layer is formed on the functional layer.

[0020] Preferably, the coating method of the functional layer solution includes any one of electrospinning, spraying, coating or blade coating.

[0021] Preferably, the parameters of the electrospinning include: voltage of 15~20kV, spinning distance of 15~20cm, and solution flow rate of 0.5~1.5mL / h.

[0022] Preferably, the annealing treatment is performed at a temperature of 80~120℃ for a time of 30~60 minutes.

[0023] A flexible electronic device includes the electrically functional leather or the electrically functional leather prepared by the method for preparing the electrically functional leather.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The electrical functional leather provided by the present invention forms a three-dimensional hybrid conductive network by conductive polymer and low-load inorganic nanomaterials. It can achieve wide-range controllable conductivity with extremely low filler addition. It is integrated into the leather with an ultra-thin functional layer, retains more than 80% breathability, and has a soft feel. The product exhibits excellent environmental and mechanical durability. After high and low temperature cycling from -30℃ to 80℃ and aging at 85% humidity, the resistance change rate is <10%, and it can withstand more than 50,000 flexes (ΔR<20%). It fundamentally solves the stubborn problems of traditional conductive leather, such as stiff feel, easy delamination, and unstable resistance, and provides a reliable flexible electronic substrate for applications such as smart wearables and flexible sensing.

[0025] (2) The method for preparing the electrical functional leather provided by the present invention utilizes a cationic modified polyurethane base coating to enhance interfacial adhesion, and then drives the conductive polymer material to self-assemble on the surface of the nanomaterial to form a dense conductive network through in-situ solvent annealing technology. Finally, a fluorosilicone modified protective layer is used for encapsulation to improve wear resistance and weather resistance. This process is ingeniously designed, which not only ensures the strong bonding and performance synergy between the functional layers, but also has good processing adaptability: the functional layers can be formed into a dense film by spraying or scraping, or a porous nanofiber membrane can be constructed by electrospinning to take into account breathability; at the same time, it supports mask spraying or digital printing to achieve local patternable processing, which provides convenience for the preparation of embedded circuits and sensor arrays. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of the electrically functional leather provided in an embodiment of the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0029] One aspect of the present invention relates to an electrically functional leather, such as Figure 1 As shown, it includes: Leather substrate; A base coating formed on at least one surface of the leather substrate; A functional layer is formed on the base coating, the functional layer comprising a hybrid conductive network formed by the combination of conductive polymer and inorganic nanomaterials; And a protective layer formed on the surface of the functional layer.

[0030] The described electrically functional leather employs a structural design of "organic-inorganic synergistic infiltration of conductive polymer materials + low-load nanomaterials," overcoming the bottleneck of traditional conductive leather requiring high amounts of conductive fillers. Conductive polymers act as "molecular wires" bridging dispersed inorganic nanomaterials, forming a three-dimensional interpenetrating conductive network within the coating or resin. The conductive polymer material encapsulates the gaps between inorganic materials, significantly reducing the infiltration threshold (inorganic filler content can be <10wt%) and improving conductivity stability. Excellent electrical performance is achieved with only 1wt%~10wt% inorganic filler content, significantly reducing costs.

[0031] This invention constructs a stable, efficient, and patternable conductive network by adding a small amount of inorganic nanomaterials without affecting the inherent properties of leather. This endows leather with excellent electrical properties and broadens the application of leather in fields such as smart wearables and electromagnetic protection.

[0032] The electrically functional leather provided by this invention has the following advantages: 1. High performance and low load: High conductivity (10⁻⁶) can be achieved by reducing the amount of inorganic nanomaterials added to 1wt%-10wt%. 2 (Ω / sq), compared to traditional methods with high addition amounts, the cost is reduced by more than 40%.

[0033] 2. Leather performance preservation: The functional layer thickness is <20μm, the breathability is >80%, and the hand feel is soft (the bending stiffness increases by <15%), which well maintains the original excellent characteristics of the leather.

[0034] 3. Stability in extreme environments: After cycling at -30℃ to 80℃ and aging at 85% humidity, the resistance change rate is <10%; the bending resistance is >50,000 times (ΔR <20%), and it can work stably in different environments.

[0035] 4. Patternable processing: Local functionalization can be achieved through mask spraying or digital printing, which can be used in embedded circuits, sensor arrays, etc., and has a wide range of application prospects.

[0036] Further, the conductive polymer includes at least one of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate, polypyrrole, polyaniline, or poly(3,4-ethylenedioxythiophene).

[0037] Furthermore, the functional layer is primarily made of a functional layer solution coated on the base layer.

[0038] Further, the functional layer solution comprises: 15wt% to 45wt% (for example, it can be, but is not limited to, any one of 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, or 45wt%, or a range between any two) of the conductive polymer, 1wt% to 10wt% (for example, it can be, but is not limited to, any one of 1wt%, 3wt%, 5wt%, 7wt%, or 10wt%, or a range between any two) of the inorganic nanomaterial, and the balance being an aqueous polyurethane solution.

[0039] By changing the mass ratio of conductive polymer to inorganic nanomaterials and the solid content, a surface resistivity of 10⁻⁶ was achieved. 2 ~10 3 Ω / sq is controllable and adjustable.

[0040] Furthermore, the aqueous polyurethane in the aqueous polyurethane solution includes one or more of the following: cationic aqueous polyurethane, anionic aqueous polyurethane, nonionic aqueous polyurethane, or zwitterionic aqueous polyurethane.

[0041] Furthermore, the content of aqueous polyurethane in the aqueous polyurethane solution is 30wt% to 50wt%, including but not limited to any one of 30wt%, 35wt%, 40wt%, 45wt% or 50wt% or any range between two of them.

[0042] Furthermore, the thickness of the functional layer is ≤20μm (for example, it can be a point value or a range between any two of 0.1μm, 0.5μm, 1μm, 5μm, 10μm, 15μm or 20μm, for example, but not limited to), and the surface resistivity is 10. 2 ~10 3 Ω / sq (for example, it can be a point value or a range between any two of 100Ω / sq, 200Ω / sq, 500Ω / sq, 800Ω / sq or 1000Ω / sq), and the resistance change rate after 50,000 bends is ≤20%.

[0043] Furthermore, the inorganic nanomaterials include at least one of silver nanowires, carbon nanotubes, graphene, carbon fibers, or Mxene.

[0044] Furthermore, the length-to-diameter ratio of the inorganic nanomaterial is >100.

[0045] Furthermore, the diameter of the silver nanowire is 30-50 nm (for example, it can be any one of 30 nm, 35 nm, 40 nm, 45 nm or 50 nm or any range between two), and the length is 10-20 μm (for example, it can be any one of 10 μm, 15 μm or 20 μm or any range between two).

[0046] Furthermore, the carbon nanotube is a multi-walled carbon nanotube with a diameter of 8-15 nm (for example, it can be any one of 8 nm, 9 nm, 10 nm, 12 nm, 14 nm or 15 nm or any range between two), and a length of 5-15 μm (for example, it can be any one of 5 μm, 7 μm, 9 μm, 11 μm, 13 μm or 15 μm or any range between two).

[0047] Furthermore, the graphene is a single-layer or few-layer graphene with a sheet diameter of 1~5μm (for example, it can be a point value or a range of any one of 1μm, 2μm, 3μm, 4μm or 5μm, or any two of them).

[0048] Furthermore, the functional layer also contains 0.5wt%~2wt% of a crosslinking agent. The crosslinking agent is added to enhance the structural stability of the functional layer. Adding a certain amount of multifunctional crosslinking agent to the functional layer initiates covalent crosslinking between the conductive polymer and the nanomaterials during the drying process, inhibiting crack formation.

[0049] Further, the crosslinking agent includes at least one of the following: polycarbodiimide, aziridine, carbodiimide, epoxy resin, oxazoline, polyfunctional aziridine, melamine resin, or organosilicon.

[0050] Furthermore, the material of the base coating includes cationic modified polyurethane. Conventional cationic modified polyurethanes in the art can be used in this invention, including but not limited to one or more of the following: quaternary ammonium salt type, tertiary amine type, sulfonium salt type, and imidazole salt type. The base coating can enhance the adhesion between the leather surface and the functional layer.

[0051] Furthermore, the thickness of the base coating is 3~8μm, including but not limited to a point value of any one of 3μm, 4μm, 5μm, 6μm, 7μm or 8μm or a range between any two.

[0052] Furthermore, the material of the protective layer includes fluorinated silicone-modified transparent polyurethane. Conventional fluorinated silicone-modified transparent polyurethanes in the art can be used in this invention, including but not limited to one or more of copolymerized, blended, or grafted modified types. The protective layer can improve the wear resistance and bending resistance of the functional layer while maintaining a surface resistivity change rate of <15% (after 10,000 bends).

[0053] Furthermore, the thickness of the protective layer is 2~5μm, including but not limited to a point value of any one of 2μm, 3μm, 4μm or 5μm or a range between any two.

[0054] This invention does not specifically limit the type of leather substrate. Any conventional leather substrate in the art can be used in this invention. In some specific embodiments, the leather substrate includes, but is not limited to, finished leather and / or leather substrate textile base fabric.

[0055] Furthermore, the leather substrate is artificial leather, which needs to be pretreated to make it a leather with strong adhesion to the subsequent coating. The pretreatment method is not specifically limited.

[0056] Another aspect of the present invention relates to a method for preparing the aforementioned electrically functional leather, comprising the following steps: (a) Forming a base coating on at least one surface of a leather substrate; (b) After coating the base layer with a functional layer solution, perform annealing to obtain a functional layer; The functional layer solution comprises: a conductive polymer and inorganic nanomaterials; (c) A protective layer is formed on the functional layer.

[0057] The method for preparing the described electrically functional leather utilizes a gradient process—cationic primer coating → solvent annealing self-assembly → cross-linking curing → microporous spinning or coating—to achieve stable anchoring of the conductive network within the leather (including natural and synthetic leather). This gradient processing not only enhances the bonding strength between layers but also allows for the control of the structure and properties of the functional layers according to different needs, ensuring the stability and reliability of the electrical functions.

[0058] The method for preparing the described electrically functional leather involves first coating the leather surface with a cationic modified polyurethane to form a base layer, which enhances the surface positive charge density and improves the adhesion of subsequent functional layers. A water-alcohol dispersion containing conductive polymers and inorganic nanomaterials is then sprayed / coated onto the base layer. In-situ solvent annealing allows the conductive polymers to self-assemble and encapsulate the nanomaterials, forming a dense conductive film. Finally, a polyurethane solution containing conductive polymers / inorganic nanomaterials is coated using microfluidic electrospinning technology to form a conductive porous layer interwoven with nanofibers, achieving a balance between conductivity and breathability.

[0059] Further, after coating at least one surface of the leather substrate with the cationic modified polyurethane, a first drying is performed to form a base coating.

[0060] Furthermore, the coating method of the cationic modified polyurethane includes: spraying and / or scraping.

[0061] Furthermore, the coating amount of the cationic modified polyurethane is 5~10 g / m². 2 including but not limited to 5g / m 2 6g / m 2 7g / m 2 8g / m 2 9g / m 2 or 10g / m 2 The point value of any one of them or the range value between any two.

[0062] Furthermore, the temperature of the first drying is 60~80℃ (for example, it can be any one of 60℃, 65℃, 70℃, 75℃ or 80℃ or any range between two), and the time is 10~20min (for example, it can be any one of 10min, 13min, 15min, 18min or 20min or any range between two).

[0063] Furthermore, the coating method of the functional layer solution includes any one of electrospinning, spraying, coating, or blade coating. The porous nanofiber membrane formed by electrospinning technology maximizes the breathability and flexibility of the leather while ensuring electrical properties. This structural design solves the problems of stiffness and poor breathability in traditional conductive leather, expanding its application possibilities in various fields.

[0064] Furthermore, the parameters of the electrospinning include: a voltage of 15~20kV (for example, it can be any one of 15kV, 16kV, 17kV, 18kV, 19kV or 20kV or a range between any two), a spinning distance of 15~20cm (for example, it can be any one of 15cm, 16cm, 17cm, 18cm, 19cm or 20cm or a range between any two), and a solution flow rate of 0.5~1.5mL / h (for example, it can be any one of 0.5mL / h, 1.0mL / h or 1.5mL / h or a range between any two).

[0065] Furthermore, the annealing temperature is 80~120℃ (for example, it can be any one of 80℃, 90℃, 100℃, 110℃ or 120℃ or any range between two), and the time is 30~60min (for example, it can be any one of 30min, 40min, 50min or 60min or any range between two).

[0066] Further, after coating the functional layer with the fluorinated silicone-modified polyurethane, a second drying process is performed to form a protective layer.

[0067] Furthermore, the coating method of the fluorinated silicone modified polyurethane includes: spraying and / or scraping.

[0068] Furthermore, the coating amount of the fluorinated silicone-modified polyurethane is 3~5 g / m². 2 (For example, it can be, but is not limited to, 3g / m 2 4g / m 2 or 5g / m 2 (the point value of any one of them or the range value between any two).

[0069] Furthermore, the temperature of the second drying is 60~80°C (for example, it can be any one of 60°C, 65°C, 70°C, 75°C or 80°C or any range between two), and the time is 20~30 min (for example, it can be any one of 20 min, 22 min, 24 min, 26 min, 28 min or 30 min or any range between two).

[0070] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0071] Example 1 The method for preparing electrically functional leather provided in this embodiment includes the following steps: 1. Ordinary cowhide shoe upper leather is selected as the leather base material, and a cationic modified polyurethane base coating is applied to its surface by spraying, with a coating amount of 8g / m². 2 Then, dry at 70°C for 15 minutes to form a base coating with a thickness of 5μm; 2. Preparation of functional solution: PEDOT:PSS, silver nanowires (40nm in diameter, 15μm in length) and polycarbodiimide were selected. The conductive polymer content was 18wt%, the inorganic nanomaterial content was 5wt%, the crosslinking agent content was 0.5wt%, and the remainder was an aqueous polyurethane solution. The functional solution was applied to the base coating by spraying. 3. The leather coated with the functional solution was subjected to in-situ solvent annealing at a temperature of 100°C for 45 minutes, so that PEDOT:PSS self-assembled and encapsulated silver nanowires to form a conductive network with a functional layer thickness of 10 μm. 4. A protective layer of fluorosilicone-modified polyurethane is applied to the surface of the functional layer by spraying, with a coating amount of 4 g / m². 2 Dry at 70°C for 25 minutes to form a protective layer with a thickness of 3μm; The prepared electrically functional leather, after testing, has a surface resistance of 400Ω / sq, a breathability loss of 12%, a soft feel (bending stiffness increase of <15%), a resistance change rate of 18% after 30,000 bends, and a resistance change rate of <10% after cycling at -30℃ to 80℃ and aging at 85% humidity.

[0072] Example 2 The method for preparing electrically functional leather provided in this embodiment includes the following steps: 1. Goat garment leather was selected as the leather substrate, and a cationic modified polyurethane primer was coated onto its surface using a scraping method, with a coating amount of 6 g / m². 2 Then, it is dried at 65°C for 18 minutes to form a base coating with a thickness of 4μm; 2. Preparation of Functional Solution: Polypyrrole, multi-walled carbon nanotubes (10 nm in diameter, 10 μm in length) and epoxy resin were selected. The conductive polymer content was 30 wt%, the inorganic nanomaterial content was 8 wt%, the crosslinking agent content was 2 wt%, and the remainder was an aqueous polyurethane solution. The functional solution was applied to the substrate coating by electrospinning. The electrospinning parameters were: voltage 18 kV, spinning distance 18 cm, and solution flow rate 1 mL / h. 3. The leather coated with the functional solution is subjected to in-situ solvent annealing at a temperature of 90°C for 50 minutes, so that the polypyrrole self-assembles and encapsulates the multi-walled carbon nanotubes to form a conductive network with a functional layer thickness of 12 μm. 4. A protective layer of fluorosilicone-modified polyurethane is applied to the surface of the functional layer by spraying, with a coating amount of 3.5 g / m². 2 Dry at 65°C for 28 minutes to form a protective layer with a thickness of 2.5 μm; The prepared electrically functional leather, after testing, has a surface resistance of 350Ω / sq, a breathability loss of only 5%, a soft feel (bending stiffness increase of <15%), a resistance change rate of 12% after 50,000 bends, and a resistance change rate of <10% after cycling at -30℃ to 80℃ and aging at 85% humidity.

[0073] Example 3 The method for preparing electrically functional leather provided in this embodiment includes the following steps: 1. Pigskin sofa leather was selected as the leather base material, and a cationic modified polyurethane base coating was applied to its surface by spraying, with a coating amount of 9g / m². 2 Then, it is dried at 75°C for 12 minutes to form a base coating with a thickness of 6μm; 2. Preparation of functional solution: Polyaniline, graphene, and melamine resin were selected. The conductive polymer content was 40 wt%, the inorganic nanomaterial content was 6 wt%, the crosslinking agent content was 1.5 wt%, and the remainder was an aqueous polyurethane solution. The functional solution was applied to the base coating by a blade coating method. 3. The leather coated with the functional solution is subjected to in-situ solvent annealing at a temperature of 110°C for 35 minutes, so that the polyaniline self-assembles and encapsulates the graphene to form a conductive network with a functional layer thickness of 15μm. 4. A protective layer of fluorosilicone-modified polyurethane is applied to the surface of the functional layer by spraying, with a coating amount of 4.5 g / m². 2 The material is dried at 75°C for 22 minutes to form a protective layer with a thickness of 4μm.

[0074] The prepared electrically functional leather, after testing, has a surface resistance of 300Ω / sq, a 10% loss in air permeability, a soft feel (bending stiffness increased by <15%), a resistance change rate of 15% after 40,000 bends, and a resistance change rate of <10% after cycling at -30℃ to 80℃ and aging at 85% humidity.

[0075] Example 4 (Artificial Leather) The method for preparing electrically functional leather provided in this embodiment includes the following steps: 1. Base Fabric Treatment: Polyester knitted fabric is selected as the base fabric and first subjected to plasma treatment (300W power, 5 minutes) to enhance surface activity; then the base fabric is immersed in polyurethane resin (30% solid content), and the coating amount is controlled at 50g / m² using the dip-coating method. 2 Pre-bake at 100℃ for 3 minutes to form a preliminary coating with a thickness of 20μm. This is the pretreatment stage of the leather base fabric, which lays the foundation for the subsequent adhesion of functional layers. 2. Primer Coating: Spray a cationic modified polyurethane primer coating onto the surface of the initial coating layer, with a coating amount of 7 g / m². 2 Dry at 70°C for 15 minutes to form a base coating with a thickness of 5μm; 3. Preparation and Coating of Functional Solution: PEDOT:PSS, silver nanowires (35nm in diameter) and polycarbodiimide were selected. The conductive polymer content was 45wt%, the inorganic nanomaterial content was 10wt%, the crosslinking agent content was 1.5wt%, and the remainder was an aqueous polyurethane solution. The functional solution was coated onto the surface of the base layer using a microgravure coating method at a coating speed of 8m / min, and the wet film thickness was controlled at 30μm. 4. Formation of functional layer: The artificial leather coated with functional solution is placed in a hot air oven for in-situ solvent annealing. It is first kept at 80°C for 20 minutes, and then heated to 100°C and kept for 30 minutes to allow PEDOT:PSS to fully self-assemble and encapsulate silver nanowires to form a continuous conductive network. The final dry film thickness of the functional layer is 12μm. 5. Protective Layer Coating: A fluorosilicone-modified polyurethane protective layer is applied to the surface of the functional layer using a slit spray gun, with a coating amount of 4 g / m². 2 Drying at 75°C for 25 minutes forms a protective layer with a thickness of 3μm, improving overall wear resistance and weather resistance.

[0076] The prepared electrically functional artificial leather, after testing, has a surface resistivity of 200 Ω / sq. Its elongation at break is 280%, which is less than 10% lower than that of artificial leather without the added functional layer. After 50,000 bending tests, the resistance change rate is 16%. After being placed in an 85% humidity environment for 30 days, the resistance change rate is less than 12%. All performance characteristics meet the requirements of applications such as smart bags and electronic device covers.

[0077] Example 5 The method for preparing the electrically functional leather provided in this embodiment differs from that in Example 4 only in step 3, specifically in the different functional solutions. The selected solutions are polyaniline and poly(3,4-ethylenedioxythiophene) (1:1), graphene, carbon fiber (1:1), and aziridine. The conductive polymer content is 30 wt%, the inorganic nanomaterial content is 8 wt%, the crosslinking agent content is 0.5 wt%, and the remainder is an aqueous polyurethane solution.

[0078] The prepared electrically functional artificial leather, after testing, has a surface resistivity of 250 Ω / sq. Its elongation at break is 300%, which is less than 8% lower than that of artificial leather without the added functional layer. After 50,000 bending tests, the resistance change rate is 15%. After being placed in an 85% humidity environment for 30 days, the resistance change rate is less than 10%. All performance characteristics meet the requirements of applications such as smart bags and electronic device covers.

[0079] Example 6 The method for preparing the electrofunctional leather provided in this embodiment differs from that in Example 4 only in step 3, where the functional solution is applied to the base coating using electrospinning technology. The electrospinning parameters are: voltage 15kV, spinning distance 15cm, and solution flow rate 0.5mL / h.

[0080] The prepared electrically functional artificial leather, after testing, has a surface resistivity of 180 Ω / sq. Its elongation at break is 300%, which is less than 9% lower than that of artificial leather without the added functional layer; after 50,000 bending tests, the resistance change rate is 12%; after being placed in an 85% humidity environment for 30 days, the resistance change rate is less than 9%. All performance characteristics meet the requirements of applications such as smart bags and electronic device covers.

[0081] Example 7 (Another method for preparing artificial leather) The method for preparing electrically functional leather provided in this embodiment includes the following steps: 1. Base Fabric Selection and Pretreatment: Nylon knitted fabric was selected as the base fabric. It was first subjected to an alkaline wash (5% sodium hydroxide solution, soaked at 60℃ for 30 minutes) to remove surface impurities and grease. Then, it was rinsed with deionized water until neutral and dried at 80℃. Next, a layer of water-based polyurethane adhesive (25% solid content) was coated onto the base fabric surface using a roller coating method, with a coating amount of 30g / m². 2 Dry at 100℃ for 2 minutes to form an adhesive layer with a thickness of 15μm, which enhances the adhesion between the subsequent coating and the base fabric; 2. Preparation of the primer layer: The cationic modified polyurethane resin was diluted with deionized water at a ratio of 1:2 and applied to the adhesive layer surface using a comma-shaped doctor blade coating method at a coating speed of 6 m / min and a coating amount of 6 g / m. 2The substrate was dried at 75℃ for 12 minutes to form a base coating with a thickness of 4μm. The zeta potential of the base coating surface was tested to be +35mV, which effectively improved the electrostatic adsorption force with the subsequent functional layers. 3. Functional Solution Preparation and Coating: PEDOT:PSS, carbon fiber, Mxene (1:2), and organosilicon were selected. The conductive polymer content was 35wt%, the inorganic nanomaterial content was 5wt%, the crosslinking agent content was 1.5wt%, and the remainder was an aqueous polyurethane solution. The functional solution was applied to the base coating using electrospinning technology. The electrospinning parameters were: voltage 20kV, spinning distance 20cm, and solution flow rate 1.5mL / h. 4. Functional layer curing: The artificial leather coated with the functional solution is subjected to in-situ solvent annealing at 90°C for 40 minutes to allow PEDOT:PSS to fully combine with carbon nanotubes to form a conductive network. The dry film thickness of the functional layer is 10μm. 5. Protective Layer Treatment: A fluorosilicone-modified polyurethane emulsion (30% solid content) is selected and applied to the surface of the functional layer using a curtain coating method. The coating speed is 5 m / min, and the coating amount is 3.5 g / m. 2 Dry at 80℃ for 20 minutes to form a protective layer with a thickness of 2.5μm.

[0082] The electrical functional artificial leather has the following test performance: surface resistance 120Ω / sq; elongation at break 320%, which is less than 8% lower than that of untreated artificial leather; resistance change rate 14% after 50,000 bending cycles; and resistance change rate <9% after temperature cycling test from -30℃ to 80℃. It is suitable for smart wearable bracelet straps, watch straps, electronic device protective cases, and other scenarios.

[0083] Example 8 The method for preparing the electrically functional leather provided in this embodiment differs from that in Example 7 only in step 3, where the functional solution is applied to the base coating using a scraping technique, and the film thickness is controlled at 25 μm.

[0084] The electrical functional artificial leather has the following test performance: surface resistance 150Ω / sq; elongation at break 280%, which is less than 8% compared with untreated artificial leather; resistance change rate of 14% after 50,000 bends; and resistance change rate of less than 9% after temperature cycling test from -30℃ to 80℃. It is suitable for smart wearable bracelet straps, watch straps, electronic device protective cases, and other scenarios.

[0085] Comparative analysis with existing technologies Compared to metal foil bonding technology: While traditional metal foil bonding can achieve high conductivity, it increases the weight of the leather by more than 30%, and it is prone to breakage after 500 bends, with a resistance change rate of >50%. The electrical functional leather of this invention increases weight by <5%, has a resistance change rate of ≤20% after 50,000 bends, and maintains good flexibility, solving the problems of high rigidity and easy breakage associated with metal foil bonding.

[0086] Compared to high-filler carbon black resin technology: Traditional carbon black filler requires more than 15wt% to achieve conductivity, resulting in stiff leather (increased bending stiffness by >50%) and decreased air permeability by >40%. This invention uses only 1wt%-5wt% inorganic filler, resulting in less than 15% increase in bending stiffness and air permeability greater than 80% of the original leather, ensuring conductivity while maximizing the preservation of the leather's inherent properties.

[0087] Compared to simple conductive polymer coating technology: When simple conductive polymers are coated on leather, the porous nature of the leather leads to a conductivity loss of >60%, and the number of abrasion cycles is <1000. This invention, through modification of the base coating and hybrid network design, achieves a conductivity retention rate of >90% and a friction cycle resistance of >5000, significantly improving the stability and durability of electrical properties.

[0088] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electrically functional leather, characterized in that, include: Leather substrate; A base coating formed on at least one surface of the leather substrate; A functional layer is formed on the base coating, the functional layer comprising a hybrid conductive network formed by the combination of conductive polymer and inorganic nanomaterials; And a protective layer formed on the surface of the functional layer.

2. The electrically functional leather according to claim 1, characterized in that, Includes at least one of the following technical features: (1) The conductive polymer includes at least one of poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, polypyrrole, polyaniline, or poly(3,4-ethylenedioxythiophene); (2) The inorganic nanomaterials include at least one of silver nanowires, carbon nanotubes, graphene, carbon fibers or Mxene; (3) the functional layer has a thickness of <20 μm and a surface resistance of 10 2 ~10 3 Ω / sq.

3. The electrically functional leather according to claim 2, characterized in that, The functional layer is mainly made of a functional layer solution coated on the base layer; The functional layer solution comprises: 15wt% to 45wt% of the conductive polymer, 1wt% to 10wt% of the inorganic nanomaterial, and the balance being an aqueous polyurethane solution.

4. The electrically functional leather according to claim 3, characterized in that, The functional layer solution also contains: 0.5wt%~2wt% of a crosslinking agent; The crosslinking agent includes at least one of the following: polycarbodiimide, aziridine, carbodiimide, epoxy resin, oxazoline, polyfunctional aziridine, melamine resin, or organosilicon.

5. The electrically functional leather according to claim 1, characterized in that, The material of the base coating includes: cationic modified polyurethane; And / or, the thickness of the base coating is 3~8μm.

6. The electrically functional leather according to claim 1, characterized in that, The protective layer is made of: fluorinated silicone-modified transparent polyurethane; And / or, the thickness of the protective layer is 2~5μm.

7. A method for preparing the electrically functional leather according to any one of claims 1 to 6, characterized in that, Includes the following steps: (a) Forming a base coating on at least one surface of a leather substrate; (b) After coating the base layer with a functional layer solution, perform an annealing treatment to obtain a functional layer; The functional layer solution comprises: a conductive polymer and inorganic nanomaterials; (c) A protective layer is formed on the functional layer.

8. The method for preparing electrically functional leather according to claim 7, characterized in that, The coating method of the functional layer solution includes any one of electrospinning, spraying, coating or blade coating; The parameters for electrospinning include: voltage of 15~20kV, spinning distance of 15~20cm, and solution flow rate of 0.5~1.5mL / h.

9. The method for preparing electrically functional leather according to claim 7, characterized in that, The annealing process is performed at a temperature of 80~120℃ for 30~60 minutes.

10. A flexible electronic device, characterized in that, The electrically functional leather includes the electrically functional leather as described in any one of claims 1 to 6 or the electrically functional leather prepared by the method described in any one of claims 7 to 9.

Images