Ultrathin flexible polymer electrothermal film and preparation method thereof

Abstract

The invention provides an ultrathin flexible polymer electrothermal film and a preparation method thereof. Relates to the technical field of electrothermal materials, and the ultrathin flexible polymer electrothermal film comprises a substrate layer, a conductive layer on one side of the substrate layer, electrode layers at the two ends of the surface of the conductive layer, and packaging layers on the surfaces of the conductive layer and the electrode layers. Wherein the conductive layer comprises the following raw materials in parts by weight: 40-90 parts of a polymer base material, 10-60 parts of a carbon conductive filler, 1-10 parts of a structural stable filler, 0-5 parts of an additive and 200-500 parts of a solvent. Meanwhile, the adopted spin-coating method is good in film forming property and few in defect, the electrode layer interface formed on the surface of the conducting layer by combining the magnetron sputtering method or the evaporation method is firm in bonding and high in conductivity, and abnormal heat production at the electrode can be prevented.

Description

Technical Field

[0001] The invention relates to the technical field of electric heating materials, in particular to an ultra-thin flexible polymer electric heating film and a preparation method thereof. Background Art

[0002] Generally, electric heating materials can be divided into metal electric heating materials, ceramic electric heating materials and polymer electric heating film materials. Metal electric heating materials, such as metal resistance wires, are the most common and widely used electric heating materials. They have the advantages of high heating temperature and fast thermal response speed, but they are inevitably heavy, uneven heating, not resistant to oxidation and chemical corrosion, electromagnetic radiation, and low electric heating efficiency. Ceramic electric heating materials have very high heat resistance and outstanding adaptability in the field of high-temperature heating. At the same time, some ceramic electric heating materials have good PTC effects, can achieve self-limiting temperature functions, and have excellent safety. However, ceramic electric heating materials face the application limitations of rigidity, heavy weight, large volume, high cost, and not resistant to chemical corrosion. Therefore, in some fields that require light, flexible, uniform heating in the form of surface, low-voltage drive, waterproof, anti-oxidation, and anti-chemical corrosion, only polymer electric heating film materials can meet their use requirements.

[0003] The polymer electric heating film material is based on polymer materials as structural support, which gives it excellent flexibility and thinness. In addition, in order to make it have good conductivity, conductive fillers are added to the polymer structural support. In order to reduce costs and meet the requirements of thinness, carbon materials are generally used as conductive fillers, such as carbon nanotubes, carbon black, graphite, etc. In general, the thickness of polymer electric heating film materials is usually above 100 μm, which still has a lot of room for improvement in some fields, such as portable electronic products, wearable electric heating products, aerospace, etc. Therefore, it is necessary to develop an ultra-thin, ultra-light and flexible polymer electric heating film material. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an ultra-thin flexible polymer electric heating film and a preparation method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides an ultra-thin flexible polymer electric heating film, the ultra-thin flexible polymer electric heating film comprising a base layer, a conductive layer on one side of the base layer, electrode layers at both ends of the surface of the conductive layer, and an encapsulation layer on the surface of the conductive layer and the electrode layer; The conductive layer comprises the following raw materials in parts by weight: 40-90 parts of a polymer matrix, 10-60 parts of a carbon conductive filler, 1-10 parts of a structurally stable filler, 0-5 parts of an additive, and 200-500 parts of a solvent.

[0006] As a further improvement of the present invention, the base layer is one of polyacrylic acid, polyimide, polyethylene terephthalate, polyethersulfone, polyethylene dimethyl methacrylate, and polyisophthalamide, and the thickness of the base layer is 5 to 30 μm.

[0007] As a further improvement of the present invention, the electrode layer is made of one of silver, copper, nickel and aluminum, and the thickness of the electrode layer is 0.2-5 μm.

[0008] As a further improvement of the present invention, the thickness of the conductive layer is 10-50 μm.

[0009] As a further improvement of the present invention, the encapsulation layer is one of polyvinylidene fluoride, polyacrylic acid, polyimide, polyvinyl pyrrolidone, thermoplastic polyurethane elastomer, silica gel, polyethylene terephthalate, polyether sulfone, polyethylene dimethyl methacrylate, polyisophthalamide, and ethyl cellulose, and the thickness of the encapsulation layer is 5 to 30 μm.

[0010] As a further improvement of the present invention, the polymer substrate is one or more of polyethylene oxide, polyvinylidene fluoride, polyacrylic acid, polyimide, polyvinyl pyrrolidone, thermoplastic polyurethane elastomer, silica gel, polyethylene terephthalate, polyether sulfone, polyethylene dimethyl methacrylate, polyisophthalamide, and ethyl cellulose.

[0011] As a further improvement of the present invention, the carbon conductive filler is one or more of graphite, carbon nanotubes, acetylene black, pyrolytic carbon black, carbon nanotubes, graphene, hard carbon, and carbon fiber; The structurally stable filler is one or more of silicon dioxide, aluminum nitride, titanium dioxide, aluminum oxide, glass fiber, magnesium oxide, zirconium dioxide, and zinc oxide.

[0012] As a further improvement of the present invention, the additive is one or more of a titanate coupling agent, a silane coupling agent, an aluminate coupling agent, a polyurethane coupling agent, an organosilicon leveling agent, an acrylic leveling agent, polypropylene glycol, tributyl phosphate, polyoxyethylene oxypropylene glycerol, a fatty alcohol, a fatty acid ester, a polyether-modified organosilicon, and a mineral oil; The solvent is one or more of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, toluene, acetone, tetrahydrofuran, ethyl acetate, isopropanol, n-butanol, ethanol, glycerol, and distilled water.

[0013] In a second aspect, the present invention provides a method for preparing an ultra-thin flexible polymer electric heating film, comprising the following steps: S1, dissolving the polymer substrate in a solvent, then adding a carbon conductive filler, a structural stabilizing filler and an additive, and stirring evenly; S2, laying the base layer flat on a glass plate, and mounting the glass plate on a spin coater suction cup, pouring the conductive slurry on the surface of the base layer, and performing drying and roller pressing after spin coating to obtain a conductive layer; S3, covering the middle area of ​​the conductive layer, and physically depositing electrode layers on both ends of the surface of the conductive layer by magnetron sputtering or evaporation; S4. Spread the conductive layer and the electrode layer on the glass plate again, and mount the glass plate on the spin coater suction cup, pour the polymer solution of the encapsulation layer on the surface of the conductive layer and the electrode layer, and dry them after the spin coating to obtain the encapsulation layer; obtain an ultra-thin flexible polymer electric heating film.

[0014] As a further improvement of the present invention, in S2 and S4, the spin coating parameters are: rotation speed 1000-3000 rpm, time 5-15 s; and drying temperature 60-150°C.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The polymer electric heating film prepared by the present invention is ultra-thin, and the total thickness of the device can be less than 30 μm. It is ultra-light and extremely flexible, and has great application value, especially in the field of wearable electronic products.

[0016] (2) The polymer electric heating film material prepared by the present invention has strong uniformity, rapid heat generation, uniform heat generation, high electric heat conversion efficiency, good oxidation resistance and chemical corrosion resistance.

[0017] (3) The spin coating method in the preparation method of the present invention has good film-forming properties, and the prepared coating has a small thickness and few defects. At the same time, the electrode layer formed on the surface of the conductive layer by combining the magnetron sputtering method or the evaporation method has a strong interface bonding and high electrical conductivity, which can prevent abnormal heat generation at the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the decomposed structure of an ultra-thin flexible polymer electric heating film in Example 1; Figure 2 Schematic diagram of the overall structure of an ultra-thin flexible polymer electric heating film in Example 1; Figure 3 The temperature of an ultra-thin flexible polymer electric heating film in Example 1 changes with time under the action of a 5 V voltage.

[0019] Explanation of the reference numerals: 1 is a packaging layer, 2 is an electrode layer, 3 is a conductive layer, 4 is a substrate layer, and 5 is a reserved hole for electrical connection of the electrode. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0022] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0023] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0024] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0025] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also indicate the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass in the embodiment description of the present application can be a mass unit known in the chemical industry such as µg, mg, g, kg, etc.

[0026] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0027] The first object of the present invention is to provide an ultra-thin flexible polymer electric heating film, comprising a base layer, a conductive layer on one side of the base layer, electrode layers at both ends of the surface of the conductive layer, and an encapsulation layer on the surface of the conductive layer and the electrode layer. The conductive layer comprises the following raw materials in parts by weight: 40-90 parts of a polymer substrate, 10-60 parts of a carbon conductive filler, 1-10 parts of a structurally stable filler, 0-5 parts of an additive, and 200-500 parts of a solvent.

[0028] The principle of this ultra-thin flexible polymer electric heating film is: During the construction of the conductive layer, the conductive layer is composed of a polymer matrix, carbon conductive fillers, structural stabilizing fillers, additives and solvents. Carbon conductive fillers (such as carbon nanotubes, graphene, etc.) provide excellent conductivity, while the polymer matrix ensures the flexibility and stability of the electric heating film. The addition of structural stabilizing fillers and additives further enhances the performance of the electric heating film.

[0029] Furthermore, the electrode layer is prepared by physically depositing the electrode layer on both ends of the surface of the conductive layer using magnetron sputtering or evaporation. This method can achieve precise deposition of the electrode without changing the properties of the conductive layer, ensuring the stable performance of the electric heating film.

[0030] Furthermore, the encapsulation layer covers the surface of the conductive layer and the electrode layer, which plays a role in protecting the electric heating film and preventing oxidation and the influence of the external environment. At the same time, the encapsulation layer also has certain insulation properties to ensure the safety of the electric heating film.

[0031] The use of polymer substrate and carbon conductive filler makes the electric heating film ultra-thin and flexible, which can adapt to various complex shapes and curved surfaces, making it possible to apply the electric heating film in multiple fields.

[0032] Carbon conductive fillers have excellent electrical conductivity and can quickly convert electrical energy into thermal energy to achieve efficient heating. At the same time, the uniformity and stability of the electric heating film are also guaranteed. The electric heating film is made of non-toxic and harmless raw materials and is environmentally friendly. At the same time, the insulating properties of the encapsulation layer ensure the safety of the use of the electric heating film. The preparation method uses conventional equipment such as a spin coater, which is simple and easy to operate, and is conducive to large-scale production and cost control.

[0033] This ultra-thin flexible polymer electric heating film and its preparation method fully utilize the characteristics of the material in principle, and its advantages are reflected in ultra-thin flexibility, efficient heating, environmental protection and safety, simple preparation process and wide application.

[0034] The polymer electric heating film provided by the present invention is ultra-thin, the total thickness of the device can be less than 30 μm, the weight is ultra-light, and the flexibility is excellent.

[0035] Furthermore, the base layer is one of polyacrylic acid (PAA), polyimide (PI), polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene dimethyl methacrylate (PMMA), and polyisophthalamide (PMIA), and the base layer has a thickness of 5 to 30 μm.

[0036] Furthermore, the electrode layer is made of one of silver, copper, nickel and aluminum, and the thickness of the electrode layer is 0.2-5 μm. The thickness can be 0.5-5 μm, 1-4 μm, 0.2-3 μm, 2-5 μm, 0.2 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, etc.

[0037] Furthermore, the thickness of the conductive layer is 10-50 μm. The thickness can be 10-40 μm, 20-50 μm, 30-50 μm, 20-40 μm, 10 μm, 20 μm, 30 μm, 25 μm, 30 μm, 40 μm, 50 μm, 15 μm, 25 μm, 35 μm, etc.

[0038] Further, the encapsulation layer is one of polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), polyimide (PI), polyvinyl pyrrolidone (PVP), thermoplastic polyurethane elastomer (TPU), silicone, polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene dimethyl methacrylate (PMMA), polyisophthalamide (PMIA), ethyl cellulose (EC), and the thickness of the encapsulation layer is 5-30 μm. The thickness can be 5-20 μm, 10-30 μm, 10-25 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 18 μm, 23 μm, 28 μm, 8 μm, etc. Furthermore, the polymer substrate is one or more of polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), polyimide (PI), polyvinyl pyrrolidone (PVP), thermoplastic polyurethane elastomer (TPU), silicone, polyethylene terephthalate (PET), polyether sulfone (PES), polyethylene dimethyl methacrylate (PMMA), polyisophthalamide (PMIA), and ethyl cellulose (EC).

[0039] Furthermore, the carbon conductive filler is one or more of graphite, carbon nanotubes, acetylene black, pyrolytic carbon black, carbon nanotubes, graphene, hard carbon, and carbon fiber.

[0040] Furthermore, the structurally stable filler is one or more of silicon dioxide, aluminum nitride, titanium dioxide, aluminum oxide, glass fiber, magnesium oxide, zirconium dioxide, and zinc oxide.

[0041] Furthermore, the additive is one or more of titanate coupling agent, silane coupling agent, aluminate coupling agent, polyurethane coupling agent, silicone leveling agent, acrylic leveling agent, polypropylene glycol, tributyl phosphate, polyoxyethylene oxypropylene glycerol, fatty alcohol, fatty acid ester, polyether modified silicone, mineral oil, etc.

[0042] Furthermore, the solvent is one or more of dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), toluene (MB), acetone, tetrahydrofuran (THF), ethyl acetate (EA), isopropanol, n-butanol, ethanol, glycerol, distilled water, etc.

[0043] The second object of the present invention is to provide a method for preparing an ultra-thin flexible polymer electric heating film, comprising the following steps: S1. Prepare conductive paste: dissolve the polymer substrate in a solvent, then add carbon conductive filler, structural stabilizing filler and additives, and stir evenly; S2, preparing a conductive layer: laying the base layer flat on a glass plate, and mounting the glass plate on a spin coater suction cup, pouring a certain amount of the conductive slurry prepared in S1 on the surface of the base layer, setting spin coating parameters and starting the spin coater, and performing drying and roller pressing after spin coating to obtain a conductive layer; S3, preparing an electrode layer: covering the middle area of ​​the conductive layer, and physically depositing an electrode layer on both ends of the surface of the conductive layer prepared in S2 by magnetron sputtering or evaporation; S4, preparing the encapsulation layer: spreading the film layer obtained in S3 on the glass plate again, and mounting the glass plate on the suction cup of the spin coater, pouring the polymer solution of the encapsulation layer on the surface of the conductive layer and the electrode layer, setting the spin coating parameters and starting the spin coater, and performing drying after the spin coating is completed to finally obtain the encapsulation layer.

[0044] The preparation method of the ultra-thin flexible polymer electric heating film of the present invention, the polymer substrate is used as the main material of the electric heating film, providing flexibility and structural support. The solvent is used to dissolve the polymer substrate so that it can be evenly mixed with other fillers. The carbon conductive filler provides the conductive properties required by the electric heating film, and realizes the electric heating effect by forming a conductive network. The structurally stable filler enhances the mechanical strength of the electric heating film to prevent deformation or breakage during use. The additive is used to adjust the fluidity, viscosity and other properties of the slurry to ensure the smooth progress of the spin coating process. In the preparation process of the conductive layer, the base layer serves as a carrier of the electric heating film to provide adhesion and support. The spin coater uniformly coats the conductive slurry on the base layer through centrifugal force to form a conductive layer with uniform thickness and good conductive properties. The solvent is removed to solidify the conductive layer, and the bonding force between the conductive layer and the base layer is increased by rolling. Covering the middle area of ​​the conductive layer ensures that the electrode layer is only deposited on both ends of the conductive layer to form the electrode of the electric heating film. The electrode material is deposited on the surface of the conductive layer by physical methods to form an electrode layer with low resistance and high adhesion. The polymer solution is used as the main material of the encapsulation layer to provide protection and insulation. The polymer solution is evenly coated on the surface of the conductive layer and the electrode layer using spin coating technology to form an encapsulation layer. The solvent is removed to solidify the encapsulation layer, protecting the electric heating film from the external environment.

[0045] Through precise spin coating process and reasonable material selection, thin and flexible electric heating films can be prepared, which are suitable for application scenarios with various curved surfaces and complex shapes. The addition of carbon conductive fillers makes the electric heating film have excellent conductivity, can quickly heat up at low voltage, and achieve efficient and energy-saving electric heating effects. The addition of structurally stable fillers enhances the mechanical strength of the electric heating film, making it less likely to deform or break during use; the setting of the encapsulation layer further improves the weather resistance and service life of the electric heating film. The entire preparation process uses mature process technologies such as spin coating, drying and physical deposition, which are simple to operate and easy to control, and are suitable for large-scale industrial production.

[0046] Further, in steps S2 and S4, the spin coating parameters are: rotation speed 1000~3000 rpm, rotation speed 2000~3000rpm, 1000~2000 rpm, 1500 rpm, 2500 rpm, etc.; time 5~15 s, and can also be 5~10 s, 10~15 s, 15s, 5 s, 10 s, 12 s; the drying temperature is 60~150℃, and can also be 60~120℃, 70~150℃, 100~140℃, 60℃, 80℃, 100℃, 120℃, 130℃, 150℃.

[0047] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0048] Embodiment 1: Embodiment 1 provides an ultra-thin flexible polymer electric heating film and a preparation method thereof, and the specific steps are as follows: S1. Prepare conductive paste: weigh 2.0 g thermoplastic polyurethane elastomer (TPU) and dissolve it in 15 g N-methyl-2-pyrrolidone (NMP) solvent, then add 1.5 g graphite, 0.75 g acetylene black and 0.25 g carbon fiber mixed carbon conductive filler, 0.2 g aluminum nitride and 0.15 g silicon dioxide structure stable filler, and 0.05 g silane coupling agent, 0.05 g acrylic leveling agent, 0.05 g polypropylene glycol additives, and stir at 1000 rpm; S2, preparation of conductive layer: a polyimide (PI) substrate layer with a thickness of 5 μm was laid flat on a glass plate, and the glass plate was mounted on a spin coater suction cup, and the conductive slurry prepared in S1 was poured on the surface of the substrate layer, and the spin coating parameters were set (rotation speed 2000 rpm, time 10 s) and the spin coater was turned on. After the spin coating was completed, drying (drying at 80°C for 3 h) and roller pressing were performed to obtain a conductive layer with a thickness of about 15 μm; S3, preparation of electrode layer: covering the middle area of ​​the conductive layer, using magnetron sputtering to physically deposit copper electrode layers on both ends of the surface of the conductive layer prepared in S2, with a single-side electrode layer width of 3 mm and a thickness of about 0.5 μm; S4, preparation of encapsulation layer: spread the film layer obtained in S3 on the glass plate again, and mount the glass plate on the suction cup of the spin coater, pour the TPU polymer liquid dissolved in NMP on the surface of the conductive layer and the electrode layer, set the spin coating parameters (rotation speed 1000 rpm, time 5 s) and turn on the spin coater, and dry it after the spin coating is completed (dry at 80°C for 3 h), and finally obtain an encapsulation layer with a thickness of about 20 μm.

[0049] The schematic diagram of the decomposition structure of an ultra-thin flexible polymer electric heating film obtained in Example 1 is as follows Figure 1 The overall structure diagram is shown in Figure 2 As shown in the figure, a 5 V DC voltage is connected to both ends of the ultra-thin flexible polymer electrothermal film (the reserved ports for the electrical connection of the electrodes), and the temperature variation curve over time is shown in the figure. Figure 3 As shown, the fever temperature can reach 78°C.

[0050] Embodiment 2: Example 2 provides an ultra-thin flexible polymer electric heating film and a preparation method thereof, and the specific steps are as follows: S1. Prepare conductive paste: weigh 2.5 g polyvinylidene fluoride (PVDF) and dissolve it in 20 g N-methyl-2-pyrrolidone (NMP) solvent, then add 1.0 g graphite, 1.0 g acetylene black, 0.15 g carbon nanotube and 0.1 g graphene mixed carbon conductive filler, 0.2 g glass fiber structure stabilizing filler, and 0.05 g silane coupling agent additive, and stir evenly at 1200 rpm; S2, preparation of conductive layer: a polyethylene terephthalate (PET) substrate layer with a thickness of 20 μm was laid flat on a glass plate, and the glass plate was mounted on a spin coater suction cup, and the conductive slurry prepared in S1 was poured on the surface of the substrate layer, and the spin coating parameters were set (rotation speed 1500 rpm, time 7 s) and the spin coater was turned on. After the spin coating was completed, the substrate was dried (dried at 100°C for 2 h) and rolled to obtain a conductive layer with a thickness of about 25 μm; S3, preparation of electrode layer: covering the middle area of ​​the conductive layer, using magnetron sputtering to physically deposit silver electrode layers on both ends of the surface of the conductive layer prepared in S2, with a single-side electrode layer width of 4 mm and a thickness of about 1 μm; S4, preparation of encapsulation layer: spread the film layer obtained in S3 on the glass plate again, and mount the glass plate on the suction cup of the spin coater, pour the PET polymer solution dissolved in DMF on the surface of the conductive layer and the electrode layer, set the spin coating parameters (rotation speed 1000 rpm, time 5 s) and turn on the spin coater, and dry it after the spin coating is completed (dry it at 80°C for 4 h), and finally obtain an encapsulation layer with a thickness of about 17 μm.

[0051] A 10 V DC voltage was connected to both ends (reserved openings for electrical connection of electrodes) of an ultra-thin flexible polymer electric heating film obtained in Example 2, and the heating temperature thereof could reach 65° C. after 150 s.

[0052] Embodiment 3: Example 3 provides an ultra-thin flexible polymer electric heating film and a preparation method thereof, and the specific steps are as follows: S1. Prepare conductive slurry: weigh 3.0 g of polyethylene oxide and dissolve it in 20 g of distilled water, then add 1.85 g of acetylene black carbon conductive filler, 0.1 g of nano titanium dioxide structure stabilizing filler, and 0.05 g of acrylic leveling agent additive, and stir evenly at 1500 rpm; S2, preparation of conductive layer: a 20 μm thick polyethylene dimethacrylate (PMMA) substrate layer was laid flat on a glass plate, and the glass plate was mounted on a spin coater suction cup, and the conductive slurry prepared in S1 was poured on the surface of the substrate layer, and the spin coating parameters were set (rotation speed 2000 rpm, time 7 s) and the spin coater was turned on. After the spin coating was completed, the substrate was dried (dried at 70°C for 3 h) and rolled to obtain a conductive layer with a thickness of about 18 μm; S3, preparation of electrode layer: covering the middle area of ​​the conductive layer, using magnetron sputtering to physically deposit nickel electrode layers on both ends of the surface of the conductive layer prepared in S2, with a single-side electrode layer width of 5 mm and a thickness of about 2 μm; S4, preparation of encapsulation layer: spread the film layer obtained in S3 on the glass plate again, and mount the glass plate on the suction cup of the spin coater, pour the PMMA polymer solution dissolved in DMF on the surface of the conductive layer and the electrode layer, set the spin coating parameters (rotation speed 1500 rpm, time 5 s) and turn on the spin coater, and dry it after the spin coating is completed (dry it at 70°C for 3 h), and finally obtain an encapsulation layer with a thickness of about 10 μm.

[0053] When a 12 V DC voltage is connected to both ends (reserved ports for electrical connection of electrodes) of an ultra-thin flexible polymer electric heating film obtained in Example 3, the heating temperature thereof can reach 53° C. after 150 s.

[0054] Embodiment 4: Example 4 provides an ultra-thin flexible polymer electric heating film and a preparation method thereof, and the specific steps are as follows: S1. Prepare conductive paste: weigh 2.0 g of polyethylene oxide (PEO) and dissolve it in 15 g of N-methyl-2-pyrrolidone (NMP) solvent, then add 1.5 g of graphite, 0.75 g of acetylene black and 0.25 g of carbon fiber mixed carbon conductive filler, 0.2 g of aluminum nitride and 0.15 g of silicon dioxide composed of structural stable filler, and 0.05 g of silane coupling agent, 0.05 g of acrylic leveling agent, 0.05 g of polypropylene glycol additives, and stir evenly at 1000 rpm; S2, preparation of conductive layer: a polyimide (PI) substrate layer with a thickness of 5 μm was laid flat on a glass plate, and the glass plate was mounted on a spin coater suction cup, and the conductive slurry prepared in S1 was poured on the surface of the substrate layer, and the spin coating parameters were set (rotation speed 1500 rpm, time 15 s) and the spin coater was turned on. After the spin coating was completed, drying (drying at 100°C for 3 h) and roller pressing were performed to obtain a conductive layer with a thickness of about 15 μm; S3, preparation of electrode layer: covering the middle area of ​​the conductive layer, using magnetron sputtering to physically deposit copper electrode layers on both ends of the surface of the conductive layer prepared in S2, with a single-side electrode layer width of 3 mm and a thickness of about 0.5 μm; S4, preparation of encapsulation layer: spread the film layer obtained in S3 on the glass plate again, and mount the glass plate on the suction cup of the spin coater, pour the TPU polymer liquid dissolved in NMP on the surface of the conductive layer and the electrode layer, set the spin coating parameters (rotation speed 1000 rpm, time 5 s) and turn on the spin coater, and dry it after the spin coating is completed (dry it at 120°C for 3 h), and finally obtain an encapsulation layer with a thickness of about 20 μm.

[0055] The ultra-thin flexible polymer electrothermal film obtained in Example 4 has a heating temperature of up to 75° C. when a 5 V DC voltage is connected to both ends of the ultra-thin flexible polymer electrothermal film (reserved ports for electrical connection of electrodes).

[0056] Embodiment 5: Example 5 provides an ultra-thin flexible polymer electric heating film and a preparation method thereof, and the specific steps are as follows: S1. Prepare conductive paste: weigh 2.5 g polyethylene terephthalate (PET) and dissolve it in 20 g N-methyl-2-pyrrolidone (NMP) solvent, then add 1.0 g graphite, 1.0 g acetylene black, 0.15 g carbon nanotube and 0.1 g graphene mixed carbon conductive filler, 0.2 g glass fiber structure stabilizing filler, and 0.05 g silane coupling agent additive, and stir at 1200 rpm; S2, preparation of conductive layer: a polyethylene terephthalate (PET) substrate layer with a thickness of 20 μm was laid flat on a glass plate, and the glass plate was mounted on a spin coater suction cup, and the conductive slurry prepared in S1 was poured on the surface of the substrate layer, and the spin coating parameters were set (rotation speed 1500 rpm, time 7 s) and the spin coater was turned on. After the spin coating was completed, drying (drying at 60°C for 3 h) and roller pressing were performed to obtain a conductive layer with a thickness of about 25 μm; S3, preparation of electrode layer: covering the middle area of ​​the conductive layer, using magnetron sputtering to physically deposit silver electrode layers on both ends of the surface of the conductive layer prepared in S2, with a single-side electrode layer width of 4 mm and a thickness of about 1 μm; S4, preparation of encapsulation layer: spread the film layer obtained in S3 on the glass plate again, and mount the glass plate on the suction cup of the spin coater, pour the PET polymer solution dissolved in DMF on the surface of the conductive layer and the electrode layer, set the spin coating parameters (rotation speed 1000 rpm, time 5 s) and turn on the spin coater, and dry it after the spin coating is completed (dry it at 80°C for 4 h), and finally obtain an encapsulation layer with a thickness of about 17 μm.

[0057] When a 10 V DC voltage is connected to both ends (reserved openings for electrical connection of electrodes) of an ultra-thin flexible polymer electric heating film obtained in Example 5, the heating temperature thereof can reach 68° C. after 150 s.

[0058] Embodiment 6: Example 6 provides an ultra-thin flexible polymer electric heating film and a preparation method thereof, and the specific steps are as follows: S1. Prepare conductive paste: weigh 3.0 g of polyimide (PI) and dissolve it in 20 g of N-methyl-2-pyrrolidone (NMP), then add 1.85 g of carbon nanotubes as carbon conductive filler, 0.1 g of nano-titanium dioxide as structural stabilizing filler, and 0.05 g of acrylic leveling agent as additive, and stir evenly at 1500 rpm; S2, preparation of conductive layer: a 20 μm thick polyethylene dimethacrylate (PMMA) substrate layer was laid flat on a glass plate, and the glass plate was mounted on a spin coater suction cup, and the conductive slurry prepared in S1 was poured on the surface of the substrate layer, and the spin coating parameters were set (rotation speed 2000 rpm, time 7 s) and the spin coater was turned on. After the spin coating was completed, the substrate was dried (dried at 70°C for 3 h) and rolled to obtain a conductive layer with a thickness of about 18 μm; S3, preparation of electrode layer: covering the middle area of ​​the conductive layer, using magnetron sputtering to physically deposit nickel electrode layers on both ends of the surface of the conductive layer prepared in S2, with a single-side electrode layer width of 5 mm and a thickness of about 2 μm; S4, preparation of encapsulation layer: spread the film layer obtained in S3 on the glass plate again, and mount the glass plate on the suction cup of the spin coater, pour the PMMA polymer solution dissolved in DMF on the surface of the conductive layer and the electrode layer, set the spin coating parameters (rotation speed 1500 rpm, time 5 s) and turn on the spin coater, and dry it after the spin coating is completed (dry it at 70°C for 3 h), and finally obtain an encapsulation layer with a thickness of about 10 μm.

[0059] The two ends of the ultra-thin flexible polymer electric heating film obtained in Example 6 (reserved ports for electrical connection of electrodes) were connected to a 12 V DC voltage, and the heating temperature thereof could reach 70° C. after 150 s.

[0060] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An ultra-thin flexible polymer electric heating film, Features: The ultra-thin flexible polymer electric heating film comprises a base layer, a conductive layer on one side of the base layer, electrode layers at both ends of the surface of the conductive layer, and a packaging layer on the surface of the conductive layer and the electrode layer; The conductive layer comprises the following raw materials in parts by weight: 40-90 parts of a polymer matrix, 10-60 parts of a carbon conductive filler, 1-10 parts of a structurally stable filler, 0-5 parts of an additive, and 200-500 parts of a solvent.

2. The ultra-thin flexible polymer electric heating film according to claim 1, Features: The base layer is one of polyacrylic acid, polyimide, polyethylene terephthalate, polyethersulfone, polyethylene dimethyl methacrylate, and polyisophthalamide, and the thickness of the base layer is 5-30 μm.

3. The ultra-thin flexible polymer electric heating film according to claim 1, Features: The electrode layer is made of one of silver, copper, nickel and aluminum, and has a thickness of 0.2-5 μm.

4. The ultra-thin flexible polymer electric heating film according to claim 1, Features: The conductive layer has a thickness of 10-50 μm.

5. The ultra-thin flexible polymer electric heating film according to claim 1, Features: The encapsulation layer is one of polyvinylidene fluoride, polyacrylic acid, polyimide, polyvinyl pyrrolidone, thermoplastic polyurethane elastomer, silica gel, polyethylene terephthalate, polyether sulfone, polyethylene dimethyl methacrylate, polyisophthalamide, and ethyl cellulose, and the thickness of the encapsulation layer is 5 to 30 μm.

6. The ultra-thin flexible polymer electric heating film according to claim 1, Features: The polymer substrate is one or more of polyethylene oxide, polyvinylidene fluoride, polyacrylic acid, polyimide, polyvinyl pyrrolidone, thermoplastic polyurethane elastomer, silica gel, polyethylene terephthalate, polyether sulfone, polyethylene dimethyl methacrylate, polyisophthalamide, and ethyl cellulose.

7. The ultra-thin flexible polymer electric heating film according to claim 1, Features: The carbon conductive filler is one or more of graphite, carbon nanotubes, acetylene black, pyrolytic carbon black, carbon nanotubes, graphene, hard carbon, and carbon fiber; The structurally stable filler is one or more of silicon dioxide, aluminum nitride, titanium dioxide, aluminum oxide, glass fiber, magnesium oxide, zirconium dioxide, and zinc oxide.

8. The ultra-thin flexible polymer electric heating film according to claim 1, Features: The additive is one or more of titanate coupling agent, silane coupling agent, aluminate coupling agent, polyurethane coupling agent, silicone leveling agent, acrylic leveling agent, polypropylene glycol, tributyl phosphate, polyoxyethylene oxypropylene glycerol, fatty alcohol, fatty acid ester, polyether modified silicone, and mineral oil; The solvent is one or more of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, toluene, acetone, tetrahydrofuran, ethyl acetate, isopropanol, n-butanol, ethanol, glycerol, and distilled water.

9. The method for preparing the ultra-thin flexible polymer electric heating film according to any one of claims 1 to 8, It is characterized in that The following steps are involved: S1, dissolving the polymer substrate in a solvent, then adding a carbon conductive filler, a structural stabilizing filler and an additive, and stirring evenly; S2, laying the base layer flat on a glass plate, and mounting the glass plate on a spin coater suction cup, pouring the conductive slurry on the surface of the base layer, and performing drying and roller pressing after spin coating to obtain a conductive layer; S3, covering the middle area of ​​the conductive layer, and physically depositing electrode layers on both ends of the surface of the conductive layer by magnetron sputtering or evaporation; S4. Spread the conductive layer and the electrode layer on the glass plate again, and mount the glass plate on the spin coater suction cup, pour the polymer solution of the encapsulation layer on the surface of the conductive layer and the electrode layer, and dry them after the spin coating to obtain the encapsulation layer; obtain an ultra-thin flexible polymer electric heating film.

10. The method for preparing the ultra-thin flexible polymer electric heating film according to claim 9, Features: In S2 and S4, the spin coating parameters are: rotation speed 1000~3000 rpm, time 5~15 s; drying temperature is 60~150℃.

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