Heating film and preparation method thereof

Abstract

The present invention discloses a heating film and a method for manufacturing the same. In one embodiment, the heating film comprises: a heating layer comprising, from bottom to top, a first woven fabric layer, a conductive coating, and electrodes; and a protective layer comprising a first protective layer and a second protective layer, the heating layer being disposed between the first and second protective layers, the first and second protective layers cooperating to encapsulate the heating layer. This embodiment utilizes a woven fabric layer as the base of the heating layer and incorporates a hot-melt adhesive film as the protective layer, thereby improving the flexibility and foldability of the heating film and thereby enhancing its thermal stability.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a heating film and a preparation method thereof. Background Art

[0002] Heating film is energy-saving and material-saving, and has the characteristics of independent switching, so it conforms to the development trend of low-carbon economy and has broad development prospects. In order to facilitate management, the heating film needs to be folded and stored in some cases.

[0003] At present, heating films usually form a heating functional layer on a substrate, and then use a protective layer for overall packaging. According to the different substrates of the heating film, the heating film is divided into the following types. The first type of heating film uses a flexible material as a substrate. The heating film has a certain flexibility and can be bent, but cannot be folded, which limits the application field of the heating film; the second type of heating film uses a polyimide film as a substrate. Although the heating film can be folded, wrinkles will be generated during the folding process, and the structure of the heating functional layer will be destroyed, thereby affecting the use of the heating film. The third type of heating film uses a non-woven fabric as a substrate and a hot melt adhesive film as a protective layer. Although the heating film has a certain elasticity, it is prone to irreversible deformation under the action of external force, which affects the use of the heating film. Therefore, in order to meet the needs of consumers and expand the application of heating films, it is urgent to develop a flexible and foldable heating film. Summary of the Invention

[0004] In view of this, an embodiment of the present invention provides a heating film and a preparation method thereof, which can improve the foldability and flexibility of the heating film while ensuring the thermal stability of the heating film.

[0005] To achieve the above-mentioned purpose, according to the first aspect of an embodiment of the present invention, a heating film is provided; the heating film includes: a heating layer, the heating layer includes a first woven fabric layer, a conductive coating, and an electrode arranged in sequence from bottom to top; a protective layer, the protective layer includes a first protective layer and a second protective layer, the heating layer is arranged between the first protective layer and the second protective layer, and the first protective layer and the second protective layer cooperate to encapsulate the heating layer.

[0006] Furthermore, the heating film also includes a second woven fabric layer, which has one or more layers; the one or more layers of the second woven fabric layer are all arranged between the first woven fabric layer and the second protective layer; preferably, the one or more layers of the second woven fabric layer are arranged between the heating layer and the second protective layer, and between the heating layer and the first protective layer.

[0007] Furthermore, when there is one second woven fabric layer, the angle between the warp direction of the first woven fabric layer and the warp direction of the adjacent second woven fabric layer is selected from 0°-90°; further, the angle between the warp direction of the first woven fabric layer and the warp direction of the adjacent second woven fabric layer is selected from 40°-50°.

[0008] Furthermore, when the second woven fabric layer has multiple layers, the angle between the warp direction of the first woven fabric layer and the warp direction of each second woven fabric layer is selected from 0°-90°; further, the angle between the warp direction of the first woven fabric layer and the warp direction of each second woven fabric layer is selected from 40°-50°.

[0009] Furthermore, the first woven fabric layer and the second woven fabric layer are both selected from one of a polyester layer, a nylon layer, a pure cotton layer, a linen layer, a wool layer, a silk layer and a blended woven layer.

[0010] Furthermore, the first protective layer and the second protective layer are both hot melt adhesive films; the hot melt adhesive films are EVA films, PA films, PES films, PO films or TPU films.

[0011] Furthermore, the heating film also includes an adhesive layer; when the second woven fabric layer has only one layer, the adhesive layer is arranged between the first woven fabric layer and the second woven fabric layer; when the second woven fabric layer has multiple layers, the adhesive layer is respectively arranged between the first woven fabric layer and the adjacent second woven fabric layer, and between adjacent second woven fabric layers; the adhesive layer is a hot melt adhesive film.

[0012] In a second aspect, an embodiment of the present invention provides a method for preparing the heating film described in the first aspect of the embodiment of the present invention. The method comprises the following steps: applying a conductive paste to a specific area on the upper surface of a first woven fabric layer to form a conductive coating, and arranging electrodes on the conductive coating to obtain a heating layer; disposing a first protective layer on the heating layer on a side having electrodes, and disposing a second protective layer on the lower surface of the first woven fabric layer to obtain a film to be packaged; and laminating the film to be packaged at 80-200°C to obtain a heating film.

[0013] Furthermore, the preparation method includes the following steps: coating a conductive slurry on a specific area on the upper surface of a first woven fabric layer to form a conductive coating, and arranging electrodes on the conductive coating to obtain a heating layer; setting a first protective layer on the side of the heating layer with the electrode, and setting an adhesive layer, a second woven fabric layer and a second protective layer in sequence from top to bottom on the lower surface of the first woven fabric layer to obtain a film to be packaged; placing the film to be packaged in a packaging machine and laminating it under conditions of 80-200°C to obtain a heating film.

[0014] Furthermore, the preparation method also includes: mixing a conductive material, a solvent and an additive to obtain a uniform dispersion; wherein the additive includes at least one of a defoamer, a film-forming agent, a resin binder, a wetting agent and a dispersant, and the mixing method includes stirring, ultrasound or sand milling; adding a thickener and a rheological agent to the dispersion and stirring evenly to obtain a conductive slurry.

[0015] Compared with the prior art, the embodiments of the present invention have at least the following beneficial effects:

[0016] 1. The embodiment of the present invention adopts a woven fabric layer as the base of the heating layer and combines a hot melt adhesive film as a protective layer, thereby improving the flexibility and foldability of the heating film.

[0017] 2. The embodiment of the present invention adopts a woven fabric layer as the anti-deformation layer of the heating film and limits the angle between two adjacent woven fabric layers in the warp direction to a preset angle range, thereby improving the anti-deformation ability of the heating film and ensuring the thermal stability of the heating film.

[0018] 3. The process for preparing the heating film according to the embodiment of the present invention is simple, pollution-free, and suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of the heating film in Example 1 of the present invention;

[0020] Figure 2 This is a left side view of the heating film in Example 1 of the present invention;

[0021] Figure 3 Schematic diagram of the structure of the heating layer in the heating film in Example 1 of the present invention;

[0022] Among them, there are a first protective layer 10 , a second protective layer 30 , a heating layer 20 , a conductive coating 201 , a first woven fabric layer 202 , an electrode 203 , an adhesive layer 40 , and a second woven surface layer 50 . DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] like Figure 1 , Figure 2 and Figure 3As shown, the present invention provides a heating film in a first aspect, comprising: a heating layer 20, comprising a first woven fabric layer 202, a conductive coating 201, and an electrode 203, arranged sequentially from bottom to top; and a protective layer, comprising a first protective layer 10 and a second protective layer 30, with the heating layer 20 disposed between the first protective layer 10 and the second protective layer 30, the first protective layer 10 and the second protective layer 30 cooperating to encapsulate the heating layer 20. In this embodiment of the present invention, under tension, the first woven fabric layer 202 does not deform in both the warp and weft directions. Therefore, by using the first woven fabric layer 202 as the base of the heating layer 20 and encapsulating the heating layer 20 in combination with the protective layer, the deformation resistance of the heating film can be effectively improved, thereby improving the foldability of the heating film.

[0025] In a preferred embodiment, the heating film further includes a second woven fabric layer 50, which has one or more layers; each of the one or more layers of the second woven fabric layer 50 is disposed between the first woven fabric layer 202 and the second protective layer 30. The one or more layers of the second woven fabric layer 50 can also be disposed between the first protective layer 10 and the heating layer 20. By using the second woven fabric layer 50 as the anti-deformation layer of the heating film, this embodiment of the present invention can effectively improve the heating film's anti-deformation capability.

[0026] In a preferred embodiment, when there is only one second woven fabric layer 50, the angle between the warp direction of the first woven fabric layer 202 and the warp direction of the adjacent second woven fabric layer 50 is selected from 0°-90°; in a more preferred embodiment, the angle between the warp direction of the first woven fabric layer 202 and the warp direction of the adjacent second woven fabric layer 50 is selected from 40°-50°. Since the first woven fabric layer 202 does not deform in the warp and weft directions during the stretching process, but deforms in the angle direction between the warp and weft directions, cracks may occur in the internal conductive coating 201 of the heating film during use, thereby changing the resistance and heating performance of the heating film, thereby affecting the use of the heating film. In this embodiment of the present invention, the angle between the warp direction of the first woven fabric layer 202 and the warp direction of the second woven fabric layer 50 is set to a preset angle, which can effectively reduce the deformation of the first woven fabric layer 202 in other directions during the stretching process, thereby improving the deformation resistance of the heating film and ensuring the thermal stability of the heating film.

[0027] In a preferred embodiment, when the second woven fabric layer 50 has multiple layers, the angle between the warp direction of the first woven fabric layer 202 and the warp direction of each second woven fabric layer 50 is selected from 0°-90° (for example, 40°, 45°, 50°, 30° or 0°, etc.); in a more preferred embodiment, the angle between the warp direction of the first woven fabric layer 202 and the warp direction of each second woven fabric layer 50 is selected from 40°-50° (for example, 40°, 45° or 50°, etc.). Specifically, the angle between the warp direction of the first woven fabric layer 202 and the warp direction of the adjacent second woven fabric layer 50, as well as the angle between the warp directions of the adjacent second woven fabric layers 50, can be arranged in descending order. For example, the angle between the warp direction of the first woven fabric layer 50 and the warp direction of the first woven fabric layer 202 is 40°, the angle between the warp direction of the second second woven fabric layer 50 and the warp direction of the first woven fabric layer 202 is 45°, and the angle between the warp direction of the third second woven fabric layer 50 and the warp direction of the first woven fabric layer 202 is 50°. Thus, by providing multiple layers of second woven fabric layers 50 as anti-deformation layers and setting the warp angles of adjacent woven fabric layers to a preset angle, the embodiment of the present invention can effectively prevent the first woven fabric from deforming in other directions during the stretching process, thereby improving the anti-deformation ability and foldability of the heating film, and further improving the thermal stability of the heating film.

[0028] In a preferred embodiment, the first woven fabric layer 202 and the second woven fabric layer 50 are each selected from a polyester layer, a nylon layer, a pure cotton layer, a linen layer, a wool layer, a silk layer, and a blended woven layer. Specifically, the first woven fabric layer 202 and the second woven fabric layer 50 can be selected from different materials. For example, the first woven fabric layer 202 is a polyester layer, and the second woven fabric layer 50 is a wool layer.

[0029] In a preferred embodiment, both the first protective layer 10 and the second protective layer 30 are hot-melt adhesive films, which can be EVA, PA, PES, PO, or TPU films. Thus, by using hot-melt adhesive films as protective layers, the embodiments of the present invention can effectively improve the waterproofness and flexibility of the heating film due to their excellent flexibility and water resistance. This allows the heating film to remain usable after machine washing or hand washing without affecting its thermal stability.

[0030] In a preferred embodiment, the heating film further includes an adhesive layer 40; when the second woven fabric layer 50 has a single layer, the adhesive layer 40 is disposed between the first woven fabric layer 202 and the second woven fabric layer 50; when the second woven fabric layer 50 has multiple layers, the adhesive layer 40 is disposed between the first woven fabric layer 202 and the adjacent second woven fabric layer 50, and between adjacent second woven fabric layers 50; the adhesive layer 40 can be a common adhesive or a hot melt adhesive film. Thus, the adhesive layer 40 is primarily used to bond adjacent woven fabric layers, so that the multiple layers of woven fabric layers form a whole to support the conductive coating 201 and the electrode 203. Preferably, the adhesive layer 40 is a hot melt adhesive film. By using a hot melt adhesive film as the adhesive layer 40, the embodiment of the present invention can effectively improve the flexibility of the hot melt adhesive film.

[0031] The embodiment of the present invention adopts a woven fabric layer as the base of the heating layer 20 and the anti-deformation layer of the heating film, and limits the angle between the warp directions of two adjacent woven fabric layers to a preset angle range, thereby effectively improving the flexibility and foldability of the heating film, thereby ensuring the thermal stability of the heating film.

[0032] In a second aspect, an embodiment of the present invention provides a method for preparing the heating film described in the first aspect of the embodiment of the present invention. The method comprises the following steps: applying a conductive paste to a specific area on the upper surface of a first woven fabric layer 202 to form a conductive coating 201, and arranging electrodes 203 on the conductive coating 201 to obtain a heating layer 20; disposing a first protective layer 10 on the side of the heating layer 20 having the electrodes 203, and disposing a second protective layer 30 on the lower surface of the first woven fabric layer 202 to obtain a film to be packaged; and laminating the film to be packaged at 80-200°C to obtain a heating film.

[0033] Specifically, a conductive paste can be applied to specific areas of the upper surface of the first woven fabric layer 202 by coating, dipping, or printing to form a conductive coating 201. Electrodes 203 are arranged on the conductive coating 201, and when energized, the conductive coating 201 operates to generate heat. Electrodes 203 can be composed of one or more of metal wires, metal foils, and metal sheets, and the metal material is primarily one or more of gold, silver, copper, iron, steel, aluminum, platinum, and the like.

[0034] In a preferred embodiment, the preparation method of the heating film includes the following steps: coating a conductive slurry on a specific area on the upper surface of the first woven fabric layer 202 to form a conductive coating 201, and arranging an electrode 203 on the conductive coating 201 to obtain a heating layer 20; setting a first protective layer 10 on the side of the heating layer 20 having the electrode 203, and setting an adhesive layer 40, a second woven fabric layer 50 and a second protective layer 30 in sequence from top to bottom on the lower surface of the first woven fabric layer 202 to obtain a film to be packaged; placing the film to be packaged in a packaging machine and laminating it under conditions of 80-200°C to obtain a heating film.

[0035] In a preferred embodiment, the preparation method of the heating film includes the following steps: coating a conductive slurry on a specific area on the upper surface of the first woven fabric layer 202 to form a conductive coating 201, and arranging an electrode 203 on the conductive coating 201 to obtain a heating layer 20; on the side of the heating layer 20 having the electrode 203, a second woven fabric layer 50 and a first protective layer 10 are sequentially arranged from bottom to top, and an adhesive layer 40, a second woven fabric layer 50 and a second protective layer 30 are sequentially arranged from bottom to top on the lower surface of the first woven fabric layer 202 to obtain a film to be packaged; the film to be packaged is placed in a packaging machine and coated at 80-200°C to obtain a heating film.

[0036] In a preferred embodiment, the preparation method of the heating film further includes: mixing a conductive material, a solvent and an auxiliary agent to obtain a uniform dispersion; wherein the auxiliary agent includes at least one of a defoamer, a film former, a resin binder, a wetting agent and a dispersant, and the mixing method includes stirring, ultrasound or sand milling; adding a thickener and a rheological agent to the dispersion and stirring evenly to obtain a conductive slurry. Specifically, a conductive material, such as one or a mixture of two or more carbon nanomaterials and metal powders, is dispersed in a solvent, and then a defoamer, a film former, a resin binder, a wetting agent and a dispersant are added, and supplemented with strong stirring, ultrasound or sand milling to achieve uniform dispersion of the conductive material in the solvent, and a conductive slurry of a certain concentration is configured, and then a certain amount of thickener and rheological agent are added to adjust the viscosity and fluidity of the slurry. Carbon nanomaterials include graphene, graphene oxide, reduced graphene oxide, modified graphene, carbon black, carbon nanotubes, carbon nanofibers, and fullerenes. The metal powder is one or more of iron powder, copper powder, nickel powder or silver powder. The solvent can be one or more of water, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, alcohols, acetone, etc. The concentration of the conductive material in the conductive paste is 0.01-10%, preferably 0.1-5%. The resin binder can be any resin binder available on the market, specifically including one or more of epoxy resin, phenolic resin, acrylic resin, alkyd resin, water-based PU resin, polyester resin, silicone resin, fluorocarbon resin, vinyl resin, cellulose resin and polyamide resin. The thickener is at least one of hydroxypropyl methylcellulose, hydroxyethyl cellulose, sodium hydroxymethyl cellulose, sodium polyacrylate, sodium alginate and PTF thickener.

[0037] The process for preparing the heating film according to the embodiment of the present invention is simple, pollution-free, and suitable for industrial production.

[0038] In addition, it should be noted that, unless otherwise specified, any range described in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0039] Example 1

[0040] Step 1: Graphene, water-based PU resin, sodium dodecylbenzene sulfonate and water are mixed uniformly in proportion to obtain a mixed solution, and then the mixed solution is sand-milled using a sand mill to uniformly disperse the graphene in the mixed solution to obtain a uniform dispersion; a certain amount of PTF thickener and leveling agent Zonyl FSO are added to the dispersion, and mechanically stirred to obtain a conductive slurry.

[0041] Step 2: Apply the conductive paste to one side of the polyester woven fabric layer through a wire rod, and then dry it at 100°C for 10 minutes to form a conductive coating 201. Attach copper wire tape as an electrode 203 on the conductive coating 201 to obtain a heating layer 20; Figure 3 As shown, the arrangement of the electrodes 203 can be adjusted according to the actual demand for power. The effective heating size of the heating layer 20 is the size of the conductive coating 201, and the effective heating size of the heating layer 20 is 20 cm×28 cm.

[0042] Step 3: Place a TPU film on the side of the heating layer 20 with the electrode 203. Place a TPU film, a polyester woven fabric layer, and a TPU film on the other side of the polyester woven fabric layer in this order from top to bottom to form a film to be packaged. The film to be packaged is placed in a packaging machine and laminated at 150°C to form a heating film. The angle between the warp direction of the polyester woven fabric used for the anti-deformation layer and the warp direction of the polyester woven fabric used for the base of the heating layer 20 is 40°.

[0043] After testing, the resistance between the two electrodes 203 was 9.1 ohms. Then, a pulling force of 10N was applied in the longitudinal and latitudinal directions of the heating film respectively. The resistance between the two electrodes 203 was still 9.2 ohms. When a pulling force of 10N was applied in the diagonal direction of the heating film, the resistance between the two electrodes 203 was 11.7 ohms.

[0044] Example 2

[0045] Example 2 is basically the same as Example 1, except that:

[0046] The angle between the warp direction of the polyester woven fabric used in the anti-deformation layer and the warp direction of the polyester woven fabric used in the base of the heating layer 20 is 45°. Testing showed that the resistance between the two electrodes 203 was 9 ohms. When a tensile force of 10 N was applied in both the warp and weft directions of the heating film, the resistance between the two electrodes 203 remained at 9.3 ohms. When a tensile force of 10 N was applied diagonally to the heating film, the resistance between the two electrodes 203 was 9.1 ohms.

[0047] Example 3

[0048] Example 3 is essentially the same as Example 1, except that the angle between the warp direction of the polyester woven fabric layer used in the anti-deformation layer and the warp direction of the polyester woven fabric used in the base of the heating layer 20 is 50°. Testing revealed that the resistance between the two electrodes 203 was 8.9 ohms. When a tensile force of 10 N was applied in both the warp and weft directions of the heating film, the resistance between the two electrodes 203 remained at 9.1 ohms. When a tensile force of 10 N was applied diagonally to the heating film, the resistance between the two electrodes 203 was 12.1 ohms.

[0049] Example 4

[0050] Example 4 is essentially the same as Example 1, except that the angle between the warp direction of the polyester woven fabric used in the anti-deformation layer and the warp direction of the polyester woven fabric used in the base of the heating layer 20 is 30°. Testing revealed that the resistance between the two electrodes 203 was 9 ohms. When a tensile force of 10 N was applied in both the warp and weft directions of the heating film, the resistance between the two electrodes 203 remained at 9.4 ohms. When a tensile force of 10 N was applied diagonally to the heating film, the resistance between the two electrodes 203 was 27 ohms.

[0051] Example 5

[0052] Example 5 is essentially the same as Example 1, except that the angle between the warp direction of the polyester woven fabric used in the anti-deformation layer and the warp direction of the polyester woven fabric used in the base of the heating layer 20 is 0°. Testing revealed that the resistance between the two electrodes 203 was 9 ohms. When a tensile force of 10 N was applied in both the warp and weft directions, the resistance between the two electrodes 203 remained at 9.3 ohms. When a tensile force of 10 N was applied diagonally to the heating film, the resistance between the two electrodes 203 was 1262 ohms.

[0053] Example 6

[0054] Example 6 is basically the same as Example 1, except that:

[0055] Step 3: A TPU film is placed on the side of the heating layer 20 with the electrode 203, and a TPU film, three layers of polyester woven fabric, and a TPU film are placed on the other side of the polyester woven fabric layer in order from top to bottom to obtain a film to be packaged; the film to be packaged is placed in a packaging machine and laminated at 150°C to obtain a heating film. TPU films are placed between adjacent polyester woven fabric layers in the three layers of polyester woven fabric for bonding, the angle between the warp direction of the first layer of polyester woven fabric and the warp direction of the polyester woven fabric used for the base of the heating layer 20 is 40°, the angle between the warp direction of the second layer of polyester woven fabric and the warp direction of the polyester woven fabric used for the base of the heating layer 20 is 45°, and the angle between the warp direction of the third layer of polyester woven fabric and the warp direction of the polyester woven fabric used for the base of the heating layer 20 is 50°. After testing, the resistance between the two electrodes 203 is 9 ohms. Then, a pulling force of 10N is applied in the longitudinal and latitudinal directions of the heating film respectively, and the resistance between the two electrodes 203 is still 9 ohms. When a pulling force of 10N is applied in the diagonal direction of the heating film, the resistance between the two electrodes 203 is 9 ohms.

[0056] It can be seen from the above embodiments that the embodiments of the present invention adopt a woven fabric layer as the base of the heating layer 20 and the anti-deformation layer, and set the angle between the warp direction of the polyester woven fabric used for anti-deformation and the warp direction of the polyester woven fabric used for the base of the heating layer 20 to a preset angle, thereby effectively reducing the deformation of the base of the heating layer 20 in other directions during the stretching process, thereby improving the anti-deformation ability of the heating film, and further ensuring that the conductive coating 201 inside the thermally conductive film is not damaged after multiple rubbing and folding, reducing the change in the resistance of the heating film, and ensuring the thermal stability of the heating film.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A heating film, characterized in that: include: A heating layer, the heating layer comprising a first woven fabric layer, a conductive coating, and an electrode arranged in sequence from bottom to top; the conductive coating is directly coated on the upper surface of the first woven fabric layer; A protective layer, the protective layer comprising a first protective layer and a second protective layer, the heating layer being disposed between the first protective layer and the second protective layer, the first protective layer and the second protective layer cooperating to encapsulate the heating layer; the first protective layer and the second protective layer being both hot melt adhesive films; The heating film also includes a second woven fabric layer, which has one or more layers. When the second woven fabric layer has one layer, the included angle between the warp direction of the first woven fabric layer and the warp direction of the adjacent second woven fabric layer is selected from 40°-50°.

2. The heating film according to claim 1, characterized in that The one or more second woven fabric layers are arranged between the heating layer and the second protective layer, and between the heating layer and the first protective layer.

3. The heating film according to claim 2, characterized in that When the second woven fabric layer has multiple layers, the included angle between the warp direction of the first woven fabric layer and the warp direction of each second woven fabric layer is selected from 40° to 50°.

4. The heating film according to claim 2, characterized in that The first woven fabric layer and the second woven fabric layer are both selected from one of a polyester layer, a nylon layer, a pure cotton layer, a linen layer, a wool layer, a silk layer and a blended woven layer.

5. The heating film according to claim 1, characterized in that The hot melt adhesive film is EVA adhesive film, PA adhesive film, PES adhesive film, PO adhesive film or TPU adhesive film.

6. The heating film according to claim 2, characterized in that Also includes a bonding layer; When the second woven fabric layer has one layer, the adhesive layer is provided between the first woven fabric layer and the second woven fabric layer; When the second woven fabric layer has multiple layers, the adhesive layer is respectively arranged between the first woven fabric layer and the adjacent second woven fabric layer, and between adjacent second woven fabric layers; The bonding layer is a hot melt adhesive film.

7. A method for preparing a heating film according to any one of claims 1 to 6, characterized in that: The steps include: Applying a conductive slurry to an area on the upper surface of the first woven fabric layer to form a conductive coating, and arranging electrodes on the conductive coating to obtain a heating layer; A first protective layer is arranged on the side of the heating layer with the electrode, and a second protective layer is arranged on the lower surface of the first woven fabric layer to obtain a film to be packaged; the first protective layer and the second protective layer are both hot melt adhesive films; Laminating the film to be packaged at 80-200° C. to obtain a heating film; The heating film further comprises a second woven fabric layer. When there is one second woven fabric layer, the included angle between the warp direction of the first woven fabric layer and the warp direction of the adjacent second woven fabric layer is selected from 40° to 50°.

8. The preparation method according to claim 7, characterized in that The steps include: A first protective layer is provided on the side of the heating layer having the electrode, and an adhesive layer, a second woven fabric layer, and a second protective layer are provided on the lower surface of the first woven fabric layer in order from top to bottom to obtain a film to be packaged; The film to be packaged is placed in a packaging machine and coated at 80-200° C. to obtain a heating film.

9. The preparation method according to claim 7, characterized in that: Also includes: The conductive material, the solvent and the auxiliary agent are mixed to obtain a uniform dispersion; wherein the auxiliary agent includes at least one of a defoaming agent, a film-forming agent, a resin binder, a wetting agent and a dispersant, and the mixing method includes stirring, ultrasonication or sand milling; Add a thickener and a rheological agent to the dispersion and stir evenly to obtain a conductive paste.

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