Multifunctional flexible far-infrared self-temperature-limiting composite electric heating material

Abstract

The invention discloses a multifunctional flexible far-infrared self-temperature-limiting composite electric heating material which comprises a flexible far-infrared self-temperature-limiting heating sheet and a power supply outgoing line. The flexible far-infrared self-temperature-limiting heating sheet is formed by thermoplastic compounding of a lower flexible insulation protective layer, a lower bonding layer, a far-infrared self-temperature-limiting heating layer, an upper bonding layer and an upper flexible insulation protective layer from bottom to top in sequence, and the power supply outgoing line comprises a connecting terminal and a power line. The power line is fixedly sealed on the heat conduction assembly of the far infrared self-temperature-limiting heating layer through the connecting terminal in a riveting or welding mode. As an electric heating component, the multifunctional flexible far-infrared self-temperature-limiting composite electric heating material can be widely applied to the heating fields of wearable equipment, clothing, home furnishing, seats, decorative walls, physiotherapy equipment, automobiles, special equipment and the like, and is low in production cost and wide in application prospect; the material is high in heat transfer efficiency, is an advanced energy-saving material, and saves energy by at least about 20% compared with an existing material.

Description

Technical Field

[0001] This invention relates to a composite electrothermal material, specifically a multifunctional flexible far-infrared self-limiting temperature composite electrothermal material. Background Technology

[0002] Far-infrared electric heating technology emerged in the mid-20th century. Utilizing radiative heat transfer and electromagnetic waves to transmit energy, it is a key energy-saving technology being promoted. With the improvement of people's living standards, the application scenarios of far-infrared technology have been further expanded, and it is widely used in infrared therapy, building heating, food drying, sterilization, wearable devices, automotive heating, and home appliances. Especially in the fields of infrared therapy, wearable devices, automotive heating, and home appliances, the flexibility of the heating element is crucial. Currently, thermoplastic films are used to encapsulate heating materials, which has the following main problems: 1) uneven heating, large temperature differences, and poor user experience; 2) poor flexibility and impact resistance; 3) short lifespan, with the film material generally not exceeding 30,000 hours. Furthermore, current far-infrared heating materials require additional temperature control during operation. However, if the temperature sensor deviates or more than two heating areas are present, the temperature will become excessively high, not only affecting the user experience but also potentially causing burns due to excessive heat buildup.

[0003] Chinese Patent Publication No. CN108848586A discloses a far-infrared flexible wearable heating element, its preparation method, and its application. The preparation method includes: providing a flexible heating element and a flexible insulating material layer. The flexible heating element is electrically connected to electrodes. The flexible heating element includes a carbon material heating film, comprising a carbon material layer, parallel or interdigitated electrodes at both ends and / or sides of the carbon material layer, and a high-temperature resistant insulating layer covering both sides of the carbon material layer. The flexible insulating material layer is placed on opposite sides of the flexible heating element. The process involves pressing and curing using a fast-pressing or pressure-transferring device to achieve sealing and insulation of the heating element and electrodes. The carbon material heating film is prepared by wet coating. This technology enables the batch production of flexible carbon material heating films with consistent quality. Through electrode design, the carbon material heating film can be driven by low voltage to generate heat, ultimately enabling its application in the field of flexible wearable heating. However, this flexible wearable heating element lacks a self-limiting temperature function and is prone to overheating during use.

[0004] Chinese Patent Publication No. CN116945530A discloses a flexible heating film, its preparation method, and its application. The method involves mixing a thermoplastic elastomer with a conductive material and extruding the resulting granules as the material for preparing the conductive layer, facilitating subsequent extrusion to form a film-like conductive layer. Furthermore, by in-mold lamination of the granules and a flexible substrate, a double-layer composite structure of an insulating layer and a conductive layer is formed. Two parallel electrodes are formed on the conductive layer, connecting them to a conductive component. A second insulating layer is then formed on one side of the conductive layer, thus covering the conductive layer. The preparation process is simple and highly efficient. The resulting flexible heating film exhibits advantages such as uniform heating, good insulation, overall flexibility, and rollability. It can be connected to voltages ranging from 5V to 220V, demonstrating a wide voltage adaptability, making it suitable for applications in the manufacture of household appliances or everyday consumer goods. While this technical solution achieves flexible functionality, it suffers from the following significant problems: 1) Using granules obtained by extruding a mixture of thermoplastic elastomer and conductive material as the material for preparing the conductive layer, the conductive pathways are connected by the granules and conductive polymer resin. During use, the granules in the conductive pathways may be lost or damaged due to fatigue caused by stress, friction, and prolonged use. This can result in minor issues such as affecting heating, or even major issues such as "lack of connection" leading to breakdown and injury to the human body due to blocked conductive pathways; 2) Although it is applicable to voltages from 5V to 220V, offering the advantage of a wide voltage range, it lacks a self-limiting temperature function. Especially when used above the safe voltage of 48V, it suffers from problems such as heat accumulation, high temperature, and breakdown, posing a significant safety hazard and causing harm to the user.

[0005] In view of the above problems, this invention discloses a multifunctional flexible far-infrared self-regulating composite electrothermal material. It has the technical features described below to solve the existing problems. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the purpose of this invention is to provide a multifunctional flexible far-infrared self-limiting temperature composite electrothermal material, the entire surface of which is a heating surface, with uniform heating, small surface temperature difference, good softness and toughness, and self-limiting temperature protection function. When applied to wearable devices, it has no obvious hard feel and no sound. Its heat is mainly radiated in the form of far-infrared rays, which has a physiotherapy effect.

[0007] The present invention provides a multifunctional flexible far-infrared self-regulating composite electric heating material through the following technical solution: A multifunctional flexible far-infrared self-regulating composite electric heating material comprises a flexible far-infrared self-regulating heating element and a power lead wire, wherein: the flexible far-infrared self-regulating heating element is formed by thermoplastic composite of a lower flexible insulating protective layer, a lower adhesive layer, a far-infrared self-regulating heating layer, an upper adhesive layer, and an upper flexible insulating protective layer from bottom to top; the power lead wire includes a connecting terminal and a power line, and the power line is fixed and sealed to the heat-conducting component of the far-infrared self-regulating heating layer by riveting or welding.

[0008] In the aforementioned multifunctional flexible far-infrared self-regulating composite electric heating material, the upper flexible insulating protective layer, the lower flexible insulating protective layer, the upper adhesive layer, and the lower adhesive layer have the same long and wide sides, and the dimensions of each long and wide side are 5-20 mm larger than the dimensions of each long and wide side of the far-infrared self-regulating heating layer.

[0009] The aforementioned multifunctional flexible far-infrared self-regulating composite electric heating material, wherein the flexible far-infrared self-regulating heating element is formed by thermoplastic composite heating using a flatbed hot press or heating roller, wherein the heating temperature is 70-160℃, the heating time is 10-120 seconds, and the pressure is 5-20 kg / m³. 2 .

[0010] The aforementioned multifunctional flexible far-infrared self-regulating composite electrothermal material, wherein the upper and lower flexible insulating protective layers are fabrics made of one of the following: polyester fiber, polyamide fiber, aramid fiber, polyphenylene sulfide fiber, polyimide fiber, polypropylene fiber, Tencel fiber, and nanocellulose fiber, and the fabric has a weight of 20-100 g / m³. 2 .

[0011] The aforementioned multifunctional flexible far-infrared self-regulating composite electrothermal material, wherein the upper and lower adhesive layers are made of thermoplastic hot melt adhesive film, and the thermoplastic hot melt adhesive film is one of the following: polyethylene-polyvinyl acetate copolymer, modified epoxy resin polymer, polyamide resin, polyethylene succinate resin, polyethylene resin, polyolefin resin, polyurethane thermoplastic elastomer, and thermoplastic elastomer. The weight of the thermoplastic hot melt adhesive film is 5-50 g / m³. 2 .

[0012] The aforementioned multifunctional flexible far-infrared self-regulating composite electrothermal material, wherein the far-infrared self-regulating heating layer comprises: a flexible substrate material and a far-infrared self-regulating conductive paste coated on the flexible substrate material, wherein the far-infrared self-regulating conductive paste comprises: a far-infrared self-regulating conductive mixture, a conductive polymer resin adhesive, and a dispersant.

[0013] The aforementioned multifunctional flexible far-infrared self-regulating composite electrothermal material, wherein the flexible substrate material is selected from either a fabric or a flexible film. The fabric is selected from glass fiber fabric, polyester fiber fabric, polyamide fiber fabric, polyvinyl alcohol acetal fiber fabric, polypropylene fiber fabric, polyvinyl chloride fiber, or polyurethane fiber. The flexible film is selected from polyimide film, polyethylene terephthalate film, polyethylene film, polypropylene film, polycarbonate film, or polyvinylidene fluoride film. The fabric has a fixed weight of 20-60 g / m³. 2 The thickness of the flexible film is 15-100 μm.

[0014] The aforementioned multifunctional flexible far-infrared self-regulating composite electrothermal material, wherein the far-infrared self-regulating conductive slurry is obtained by mixing a far-infrared self-regulating conductive mixture, a conductive polymer resin adhesive, and a dispersant in pure water to form a solution, which is then heated and homogenized. The mass percentages of the three raw materials are: far-infrared self-regulating conductive mixture 75%-90%, conductive polymer resin adhesive 7%-14%, and dispersant 1%-3%.

[0015] The aforementioned multifunctional flexible far-infrared self-regulating composite electrothermal material comprises, wherein, the far-infrared self-regulating conductive mixture is added to a pure aqueous solution containing a dispersant at a constant temperature of 40-85℃ and homogenized for 15-30 minutes to form a far-infrared self-regulating conductive mixture solution; the far-infrared self-regulating conductive mixture solution is heated to 50-90℃ and kept at a constant temperature; a conductive polymer resin adhesive is added and homogenized for 30-60 minutes to form a far-infrared self-regulating conductive slurry; the concentration of the far-infrared self-regulating conductive slurry is 45%-75%.

[0016] The aforementioned multifunctional flexible far-infrared self-regulating composite electrothermal material comprises, wherein the far-infrared self-regulating conductive mixture is formed by air-jet pulverization of a far-infrared conductive mixture and a self-regulating polymer at a mass percentage of 90%-95%: 5%-10%; the far-infrared conductive mixture is formed by air-jet pulverization of 55%-75% carbon fiber, 10%-20% graphite, 14%-22% conductive carbon black, and 1%-3% graphene; the self-regulating polymer is one or a combination of polyethylene glycol, polypropylene, polyethylene, and polyvinylidene fluoride; the self-regulating polymer is in powder form with a particle size of 10-25 μm; the graphite is artificial graphite or natural graphite with a particle size of 10-30 μm; the conductive carbon black has a particle size of 2-20 μm; and the graphene is graphene oxide.

[0017] In the aforementioned multifunctional flexible far-infrared self-limiting temperature composite electrothermal material, the carbon fiber is chopped carbon fiber, which is composed of polyacrylonitrile carbon fibers with lengths of 0.5mm, 1mm and 2mm, and the mass percentage of the chopped carbon fibers with lengths of 0.5mm, 1mm and 2mm is 40%-60%: 30%-40%: 10%-20%.

[0018] In the aforementioned multifunctional flexible far-infrared self-limiting temperature composite electrothermal material, the conductive polymer resin adhesive is one of water-based polyurethane resin, water-based acrylic resin, water-based epoxy resin, or water-based polyester resin.

[0019] In the aforementioned multifunctional flexible far-infrared self-limiting temperature composite electrothermal material, the dispersant may be one or a combination of sodium carboxymethyl cellulose, polyvinylpyrrolidone, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate.

[0020] The aforementioned multifunctional flexible far-infrared self-regulating thermoplastic composite heating material, wherein the far-infrared self-regulating conductive paste is uniformly coated onto a flexible substrate material by a coating machine, and the far-infrared self-regulating conductive paste is coated onto the flexible substrate material 2-3 times, with each coating weighing 5-20 g / m³. 2 After each coating is completed, drying is carried out using a heated roller with a rotation speed of 1-4 m / min and a drying temperature of 70-110℃.

[0021] In the aforementioned multifunctional flexible far-infrared self-regulating composite electrothermal material, conductive components are respectively provided on a set of symmetrical long or wide sides of the far-infrared self-regulating heating layer. The conductive components are made of either conductive copper foil or conductive silver paste.

[0022] The aforementioned multifunctional flexible far-infrared self-regulating composite electric heating material is wherein the flexible far-infrared self-regulating heating element is formed by hot pressing in one step. The hot pressing is performed using either a flatbed hot press or a hot rolling mill, with a hot pressing time of 10s-120s and a hot pressing temperature of 70-160℃.

[0023] In the aforementioned multifunctional flexible far-infrared self-regulating composite electric heating material, the connecting terminal is welded or riveted to the conductive component exposed by grinding at one end of the flexible far-infrared self-regulating heating element. The connecting terminal is an OT type connecting terminal. The T-end wiring groove of the OT type terminal is used to clamp and fix the power cord. The O-end of the OT type terminal is welded or riveted to the conductive component exposed by grinding at one end of the flexible far-infrared self-regulating heating element.

[0024] In the aforementioned multifunctional flexible far-infrared self-regulating composite electric heating material, the connecting terminals are welded or riveted to the conductive components of the flexible far-infrared self-regulating heating element and then insulated and sealed with insulating sealant. The insulating sealant can be one of epoxy resin sealant, silicone sealant, or acrylic sealant.

[0025] The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material of this invention, due to the adoption of the above-mentioned solution, has the following advantages and positive effects compared with the prior art:

[0026] 1) The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material of the present invention has a wide range of applications. As an electric heating element, it can be widely used in heating fields such as wearable devices, clothing, home furnishings, chairs, decorative walls, physiotherapy equipment, automobiles, and special equipment. It has low production costs and broad application prospects.

[0027] 2) The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material of the present invention has a wide applicable voltage range and can be designed within the AC / DC range of 3.6-220V according to actual needs, which can meet the needs of most application scenarios.

[0028] 3) The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material of the present invention has a heating surface on the entire surface. The heat transfer is mainly through far-infrared radiation. The electrothermal conversion efficiency can reach 99%, and the electro-thermal radiation conversion efficiency can reach 70%. It has high heat transfer efficiency and is an advanced energy-saving material. Compared with existing materials, it saves at least 20% energy.

[0029] 4) The multifunctional flexible far-infrared self-limiting temperature composite electric heating material of the present invention has a Shore hardness of 10-25A, no hard texture, good softness, folding resistance, and abrasion resistance;

[0030] 5) The heating element of the multifunctional flexible far-infrared self-limiting temperature composite electrothermal material of the present invention is a three-dimensional conductive network built with short-cut carbon fibers. Its conductive path is a physical structure built with short carbon fibers, which has the characteristics of structural stability and its service life can reach more than 100,000 hours.

[0031] 6) The multifunctional flexible far-infrared self-limiting temperature composite electric heating material of the present invention has a self-limiting temperature function, which can not only prevent heat storage or overheating from causing harm to the human body, but also save energy and electricity. Attached Figure Description

[0032] Figure 1 This is a structural diagram of the flexible far-infrared self-limiting heating element in the multifunctional flexible far-infrared self-limiting composite electrothermal material of the present invention;

[0033] Figure 2 This is a structural diagram of the far-infrared self-limiting heating layer in the multifunctional flexible far-infrared self-limiting composite electrothermal material of the present invention;

[0034] Figure 3 This is a structural diagram of the OT terminal in the multifunctional flexible far-infrared self-limiting temperature composite electrothermal material of the present invention;

[0035] Among them, 11-upper flexible insulating protective layer, 12-lower flexible insulating protective layer, 21-upper adhesive layer, 22-lower adhesive layer, 3-far-infrared self-limiting heating layer, 4-OT type connection terminal, 5-power cord, and 6-conductive component. Specific Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0037] Please refer to Figures 1 to 3 This invention discloses a multifunctional flexible far-infrared self-regulating composite electric heating material, comprising a flexible far-infrared self-regulating heating element and a power lead wire. The flexible far-infrared self-regulating heating element is formed by thermoplastic composite of a lower flexible insulating protective layer 12, a lower adhesive layer 22, a far-infrared self-regulating heating layer 3, an upper adhesive layer 21, and an upper flexible insulating protective layer 11 from bottom to top. The power lead wire includes a connecting terminal and a power line 5. The power line 5 is fixed and sealed to the conductive component of the far-infrared self-regulating heating layer by riveting or welding.

[0038] More preferably, conductive components 6 are respectively disposed on a set of symmetrical long or wide sides of the far-infrared self-limiting heating layer 3. The conductive components 6 can be either conductive copper foil or conductive silver paste. In this embodiment, conductive copper foil is selected as the conductive component.

[0039] The upper flexible insulating protective layer 11, the lower flexible insulating protective layer 12, the upper adhesive layer 21 and the lower adhesive layer 22 have the same long side and wide side, and each of their long side and wide side is 5-20mm larger than each of their long side and wide side of the far-infrared self-limiting heating layer 3.

[0040] The flexible far-infrared self-regulating heating element is formed by thermoplastic composite heating using a flatbed hot press or heating rollers. The heating temperature is 70-160°C, the heating time is 10-120 seconds, and the pressure is 5-20 kg / m³. 2 .

[0041] The upper flexible insulating protective layer 11 and the lower flexible insulating protective layer 12 are made of fabrics selected from polyester fiber, polyamide fiber, aramid fiber, polyphenylene sulfide fiber, polyimide fiber, polypropylene fiber, Tencel fiber, and nanocellulose fiber, and the fabric has a fixed weight of 20-100 g / m³. 2 .

[0042] The upper adhesive layer 21 and the lower adhesive layer 22 are made of thermoplastic hot melt adhesive film. The thermoplastic hot melt adhesive film can be one of the following: polyethylene-polyvinyl acetate copolymer, modified epoxy resin polymer, polyamide resin, polyethylene succinate resin, polyethylene resin, polyolefin resin, polyurethane thermoplastic elastomer, or thermoplastic elastomer. The weight of the thermoplastic hot melt adhesive film is 5-50 g / m³. 2 .

[0043] The far-infrared self-regulating heating layer 3 comprises: a flexible substrate material and a far-infrared self-regulating conductive paste coated on the flexible substrate material. The far-infrared self-regulating conductive paste comprises: a far-infrared self-regulating conductive mixture, a conductive polymer resin adhesive, and a dispersant. The flexible substrate material can be selected from either a fabric or a flexible film. The fabric can be selected from glass fiber fabric, polyester fiber fabric, polyamide fiber fabric, polyvinyl acetal fiber fabric, polypropylene fiber fabric, polyvinyl chloride fiber, or polyurethane fiber. The flexible film can be selected from polyimide film, polyethylene terephthalate film, polyethylene film, polypropylene film, polycarbonate film, or polyvinylidene fluoride film. The fabric has a fixed weight of 20-60 g / m³. 2 The thickness of the flexible film is 15-100 μm.

[0044] The far-infrared self-regulating conductive slurry is obtained by mixing a far-infrared self-regulating conductive mixture, a conductive polymer resin adhesive, and a dispersant in pure water to form a solution, followed by heating and homogenization. The mass percentages of the three raw materials are: far-infrared self-regulating conductive mixture 75%-90%, conductive polymer resin adhesive 7%-14%, and dispersant 1%-3%. The far-infrared self-regulating conductive mixture is added to a pure aqueous solution containing a dispersant at a constant temperature of 40-85℃ and homogenized for 15-30 minutes to form a far-infrared self-regulating conductive mixture solution. The far-infrared self-regulating conductive mixture solution is then heated to 50-90℃ and held at that temperature. The conductive polymer resin adhesive is added and homogenized for 30-60 minutes to form the far-infrared self-regulating conductive slurry. The concentration of the far-infrared self-regulating conductive slurry is 45%-75%.

[0045] The far-infrared self-regulating conductive mixture is formed by air-jet milling and mixing of a far-infrared conductive mixture and a self-regulating polymer at a mass percentage of 90%-95%: 5%-10%. The far-infrared conductive mixture is composed of 55%-75% carbon fiber, 10%-20% graphite, 14%-22% conductive carbon black, and 1%-3% graphene, mixed by air-jet milling. The carbon fiber is chopped carbon fiber, specifically composed of polyacrylonitrile-based carbon fibers with lengths of 0.5mm, 1mm, and 2mm, with a mass percentage of 40%-60%: 30%-40%: 10%-20%. The self-regulating polymer is one or a combination of polyethylene glycol, polypropylene, polyethylene, and polyvinylidene fluoride, and is in powder form with a particle size of 10-25µm. The graphite used is artificial or natural graphite with a particle size of 10-30 μm, and the conductive carbon black has a particle size of 2-20 μm. The graphene used is graphene oxide.

[0046] The conductive polymer resin adhesive may be one of waterborne polyurethane resin, waterborne acrylic resin, waterborne epoxy resin or waterborne polyester resin.

[0047] The dispersant may be one or a combination of sodium carboxymethyl cellulose, polyvinylpyrrolidone, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate.

[0048] The far-infrared self-regulating conductive paste is uniformly coated onto a flexible substrate material using a coating machine. The far-infrared self-regulating conductive paste is coated 2-3 times onto the flexible substrate material, with each coating weighing 5-20 g / m³. 2 After each coating is completed, drying is carried out using a heated roller with a rotation speed of 1-4 m / min and a drying temperature of 70-110℃.

[0049] The aforementioned multifunctional flexible far-infrared self-regulating composite electric heating material, wherein the flexible far-infrared self-regulating heating element is manufactured by one-time hot pressing. The hot pressing is performed using a flatbed hot press or hot rollers, with a pressing time of 10-120 seconds and a pressing temperature of 70-160℃. The connecting terminal is welded or riveted to the exposed conductive component at one end of the flexible far-infrared self-regulating heating element. The connecting terminal is an OT-type connecting terminal 4. The T-end wiring groove of the OT-type connecting terminal 4 is used to secure the power cord, and the O-end of the OT-type connecting terminal 4 is welded or riveted to the exposed conductive component 6 at one end of the flexible far-infrared self-regulating heating element. Insulation and sealing are achieved at the connection point between the connecting terminal and the conductive component 6 of the flexible far-infrared self-regulating heating element using insulating sealant. The insulating sealant can be one of epoxy resin sealant, silicone sealant, or acrylic sealant.

[0050] This invention relates to a multifunctional flexible far-infrared self-limiting temperature composite electrothermal material that can be widely used as an electric heating element in heating fields such as wearable devices, clothing, home furnishings, chairs, decorative walls, physiotherapy equipment, automobiles, and special equipment. It has low production costs and broad application prospects. It has high heat transfer efficiency and is an advanced energy-saving material that saves at least 20% energy compared to existing materials.

[0051] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0053] In summary, the above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A multifunctional flexible far-infrared self-regulating temperature composite electric heating material, comprising a flexible far-infrared self-regulating temperature heating element and a power lead wire, characterized in that: The flexible far-infrared self-regulating heating element is formed by thermoplastic composite of a lower flexible insulating protective layer, a lower adhesive layer, a far-infrared self-regulating heating layer, an upper adhesive layer, and an upper flexible insulating protective layer from bottom to top. The power lead includes a connecting terminal and a power line. The power line is fixed and sealed to the conductive component of the far-infrared self-regulating heating layer by the connecting terminal through riveting or welding.

2. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 1, characterized in that... The upper flexible insulating protective layer, the lower flexible insulating protective layer, the upper adhesive layer, and the lower adhesive layer have the same long side and wide side, and the dimensions of each long side and wide side are 5-20 mm larger than the dimensions of each long side and wide side of the far-infrared self-limiting heating layer.

3. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 2, characterized in that... The flexible far-infrared self-regulating heating element is formed by thermoplastic composite heating using a flatbed hot press or heating rollers. The heating temperature is 70-160℃, the heating time is 10-120s, and the pressure is 5-20kg / m³. 2 .

4. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 1, characterized in that... The upper and lower flexible insulating protective layers are made of fabric selected from polyester fiber, polyamide fiber, aramid fiber, polyphenylene sulfide fiber, polyimide fiber, polypropylene fiber, Tencel fiber, and nanocellulose fiber, and the fabric has a weight of 20-100 g / m³. 2 .

5. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 1, characterized in that... The upper and lower adhesive layers are made of thermoplastic hot melt adhesive film. The thermoplastic hot melt adhesive film is selected from one of the following: polyethylene-polyvinyl acetate copolymer, modified epoxy resin polymer, polyamide resin, polyethylene succinate resin, polyethylene resin, polyolefin resin, polyurethane thermoplastic elastomer, and thermoplastic elastomer. The weight of the thermoplastic hot melt adhesive film is 5-50 g / m³. 2 .

6. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 1, characterized in that... The far-infrared self-regulating heating layer comprises: a flexible substrate material and a far-infrared self-regulating conductive paste coated on the flexible substrate material. The far-infrared self-regulating conductive paste comprises: a far-infrared self-regulating conductive mixture, a conductive polymer resin adhesive, and a dispersant.

7. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 6, characterized in that... The flexible substrate material is selected from either a fabric or a flexible film. The fabric is selected from glass fiber fabric, polyester fiber fabric, polyamide fiber fabric, polyvinyl alcohol acetal fiber fabric, polypropylene fiber fabric, polyvinyl chloride fiber, or polyurethane fiber. The flexible film is selected from polyimide film, polyethylene terephthalate film, polyethylene film, polypropylene film, polycarbonate film, or polyvinylidene fluoride film. The fabric has a fixed weight of 20-60 g / m³. 2 The thickness of the flexible film is 15-100 μm.

8. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 6, characterized in that... The far-infrared self-regulating conductive slurry is obtained by mixing a far-infrared self-regulating conductive mixture, a conductive polymer resin adhesive, and a dispersant in pure water to form a solution, which is then heated and homogenized. The mass percentages of the three raw materials are: far-infrared self-regulating conductive mixture 75%-90%, conductive polymer resin adhesive 7%-14%, and dispersant 1%-3%.

9. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 8, characterized in that... The far-infrared self-regulating conductive mixture is added to a pure aqueous solution containing a dispersant at a constant temperature of 40-85℃ and homogenized for 15-30 minutes to form a far-infrared self-regulating conductive mixture solution. The far-infrared self-regulating conductive mixture solution is then heated to 50-90℃ and kept at a constant temperature. A conductive polymer resin adhesive is added and homogenized for 30-60 minutes to form a far-infrared self-regulating conductive slurry. The concentration of the far-infrared self-regulating conductive slurry is 45%-75%.

10. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 8, characterized in that... The far-infrared self-regulating conductive mixture is formed by air-jet pulverization of far-infrared conductive mixture and self-regulating polymer at a mass percentage of 90%-95%: 5%-10%. The far-infrared conductive mixture is formed by air-jet pulverization of carbon fiber 55%-75%, graphite 10%-20%, conductive carbon black 14%-22%, and graphene 1%-3% by mass percentage. The self-regulating polymer is one or a combination of polyethylene glycol, polypropylene, polyethylene, and polyvinylidene fluoride. The self-regulating polymer is in powder form with a particle size of 10-25 μm. The graphite is artificial graphite or natural graphite with a particle size of 10-30 μm. The conductive carbon black has a particle size of 2-20 μm. The graphene is graphene oxide.

11. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 10, characterized in that... The carbon fiber is chopped carbon fiber, which is composed of polyacrylonitrile carbon fibers with lengths of 0.5 mm, 1 mm and 2 mm, and the mass percentage of the chopped carbon fibers with lengths of 0.5 mm, 1 mm and 2 mm is 40%-60%: 30%-40%: 10%-20%.

12. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 6, characterized in that... The conductive polymer resin adhesive is one of waterborne polyurethane resin, waterborne acrylic resin, waterborne epoxy resin, or waterborne polyester resin.

13. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 12, characterized in that... The dispersant may be one or a combination of sodium carboxymethyl cellulose, polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate.

14. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 9, characterized in that... The far-infrared self-regulating conductive paste is uniformly coated onto a flexible substrate material using a coating machine. The far-infrared self-regulating conductive paste is coated 2-3 times onto the flexible substrate material, with each coating weighing 5-20 g / m³. 2 After each coating is completed, drying is carried out using a heated roller with a rotation speed of 1-4 m / min and a drying temperature of 70-110℃.

15. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 1, characterized in that... The far-infrared self-limiting heating layer is further provided with conductive components on a set of symmetrical long or wide sides, and the conductive components are made of either conductive copper foil or conductive silver paste.

16. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 15, characterized in that... The flexible far-infrared self-limiting heating element is manufactured by hot pressing in one step. The hot pressing is carried out using either a flatbed hot press or a hot rolling mill. The hot pressing time is 10s-120s and the hot pressing temperature is 70-160℃.

17. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 1, characterized in that... The connecting terminal is welded or riveted to the conductive component exposed by grinding at one end of the flexible far-infrared self-regulating heating element. The connecting terminal is an OT type connecting terminal. The T-end wiring groove of the OT type terminal is used to clamp and fix the power cord. The O-end of the OT type terminal is welded or riveted to the conductive component exposed by grinding at one end of the flexible far-infrared self-regulating heating element.

18. The multifunctional flexible far-infrared self-limiting temperature composite electrothermal material as described in claim 17, characterized in that... The connection terminals are welded or riveted to the conductive components of the flexible far-infrared self-limiting heating element and then insulated and sealed with insulating sealant. The insulating sealant is one of epoxy resin sealant, silicone sealant, or acrylic sealant.

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