Preparation method of integrated electric floor heating system

Abstract

The invention provides an integrated electric floor heating structure. The electric heating film comprises an electric heating film, the electric heating film comprises a base film layer, a conductive carbon film layer, an electrode layer, a first hot melt adhesive layer, a middle film layer, a second hot melt adhesive layer, a shielding layer and a third hot melt adhesive layer which are sequentially arranged from bottom to top, and the electrode layer comprises a silver paste electrode area and a copper foil electrode area. The first hot melt adhesive layer, the second hot melt adhesive layer and the third hot melt adhesive layer all contain moisture curing reaction type polyurethane hot melt adhesive. A fourth hot melt adhesive layer and a lower protection layer can be arranged below the base film layer, and an upper protection layer can be arranged above the third hot melt adhesive layer. When damage phenomena such as punching occur on a construction site, the shielding layer and the carbon film at the punching position are short-circuited to generate local high temperature, part of the exposed shielding layer is ablated, meanwhile, hot melt adhesive above and below the shielding layer is locally melted, and melted adhesive liquid covers the shielding layer and the conductive carbon film layer, so that the shielding layer and the conductive carbon film layer are not short-circuited any more. The electrothermal film is waterproof, has a shielding layer self-repairing function, and can be used for an electric floor heating system.

Description

Technical Field

[0001] The present invention specifically relates to a waterproof and self-repairing electric heating film and a preparation method and application thereof. Background Art

[0002] Electric floor heating is a new type of floor heating method. Its main principle is to lay electric heating film on the ground and use the heat generated by the electric heating film to increase the indoor temperature. The electric heating film is usually composed of PET base film, conductive carbon film, silver paste electrode, PET cover film and shielding layer. Among them, waterproofness and anti-leakage current shielding layer are important guarantees for the normal operation of electric floor heating. Once the waterproof or shielding layer is damaged, the electric floor heating may not work properly and may even cause safety problems.

[0003] In the existing electric floor heating preparation technology, a conductive carbon paste coating is usually applied to the PET base film in a whole or patterned manner, and then silver paste electrodes are applied on both sides of the carbon paste coating. After that, a PET hot melt adhesive film is used to bond the PET carbon-coated base film as a whole, and the PET hot melt adhesive film forms a PET cover film. Then, a shielding layer is bonded to the PET cover film using double-sided adhesive or hot melt adhesive. Finally, a PVC film is used for bagging and overall packaging.

[0004] However, the existing electric floor heating preparation technology still has some problems in terms of waterproofing and shielding layer protection. First, due to the moisture permeability of polymer films such as PVC and PET, the moisture in the ground cement leveling layer will penetrate through the PVC and PET films into the carbon-coated layer, causing changes in the resistance of the electric heating film and affecting the normal operation of the electric floor heating. Secondly, if there is damage such as drilling at the construction site, the electric heating film may leak current to the earth, causing safety problems such as leakage protection tripping. Finally, the existing electric floor heating preparation technology cannot achieve self-repair after the shielding layer is damaged, and can only smash the ground leveling layer to replace the floor heating film, which will seriously affect the use effect and service life of the electric floor heating. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an electric heating film which is waterproof and has a self-repairing function of the shielding layer, and an electric floor heating system containing the electric heating film.

[0006] The present invention also provides a method for preparing an electric heating film. The electric heating film prepared by the method has waterproof and shielding layer self-repairing functions. When used in an electric floor heating system, its service life can be extended and its use effect can be improved.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0008] An electric heating film comprises a base film layer, a conductive carbon film layer, an electrode layer, a first hot melt adhesive layer, an intermediate film layer, a second hot melt adhesive layer, a shielding layer and a third hot melt adhesive layer which are arranged in sequence from bottom to top, wherein the electrode layer comprises a silver paste electrode region and a copper foil electrode region, and the first hot melt adhesive layer, the second hot melt adhesive layer and the third hot melt adhesive layer all contain moisture-curing reactive polyurethane hot melt adhesive (PUR hot melt adhesive).

[0009] In the present invention, moisture-curing reactive polyurethane hot melt adhesive (PUR hot melt adhesive) refers to a polyurethane adhesive that can be cured in the presence of moisture, the moisture in the moisture can act as a catalyst for the curing reaction, and the adhesive belongs to the hot melt adhesive type, that is, it will melt when heated.

[0010] In some embodiments, the electric heating film further includes a fourth hot melt adhesive layer and a lower protective layer disposed below the base film layer.

[0011] Preferably, the fourth hot melt adhesive layer contains moisture-curing reactive polyurethane hot melt adhesive. The use of this hot melt adhesive composition can further reduce the influence of moisture in the cement leveling layer on the resistance of the conductive carbon film layer, thereby extending the service life and use effect of the electric heating film.

[0012] In some embodiments, the electric heating film further comprises an upper protective layer disposed above the third hot melt adhesive layer. The upper protective layer and the lower protective layer play a packaging role for the upper and lower surfaces of the electric heating film.

[0013] Preferably, the material of the upper protective layer is selected from one or more combinations of PVC, PET, PI, PP, and PE, and the material of the lower protective layer is selected from one or more combinations of PVC, PET, PI, PP, and PE.

[0014] In some embodiments, the electric heating film further comprises a current-carrying bar disposed between the shielding layer and the third hot melt adhesive layer. The current-carrying bar can collect the distributed capacitive induction current generated from the shielding layer when the electric heating film is powered on and introduce it into the zero line loop of the electric heating film.

[0015] In some embodiments, the raw materials of the moisture-curing reactive polyurethane hot melt adhesive include polyols, diisocyanates and silane coupling agents, and the polyols are selected from polyether polyols and / or polyester polyols. The siloxane groups in the silane coupling agent can be hydrolyzed into -Si-OH groups under humid conditions, and the -Si-OH groups on different polyurethane molecular chains can shrink, thereby causing the polyurethane hot melt adhesive to crosslink and cure.

[0016] In some embodiments, the melting point of the moisture-curing reactive polyurethane hot melt adhesive is in the range of 110 to 180°C.

[0017] In some embodiments, the thickness of the first hot melt adhesive layer is 10-100 μm.

[0018] In some embodiments, the second hot melt adhesive layer has a thickness of 10 to 200 μm.

[0019] In some embodiments, the thickness of the third hot melt adhesive layer is 10 to 200 μm.

[0020] In some embodiments, the raw materials of the moisture-curing reactive polyurethane hot melt adhesive include 40 to 80 parts of polyol, 12 to 16 parts of diisocyanate and 1 to 6 parts of silane coupling agent in parts by weight. In the moisture-curing reactive polyurethane hot melt adhesive, the water absorption rate of the polyurethane hot melt adhesive can be reduced by modifying the silane coupling agent. The use of the moisture-curing reactive polyurethane hot melt adhesive of this composition in the adhesive area (first hot melt adhesive layer) of the electrode layer can effectively reduce the probability of moisture in the cement leveling layer penetrating the base film layer and the electrode layer into the conductive carbon film layer, thereby reducing the influence of moisture on the resistance of the conductive carbon film layer.

[0021] Preferably, in parts by weight, the raw materials of the moisture-curing reactive polyurethane hot melt adhesive include 10 to 30 parts of polyester polyol, 30 to 50 parts of polyether polyol, 12 to 16 parts of diisocyanate and 1 to 6 parts of silane coupling agent.

[0022] In some embodiments, the diisocyanate is selected from one or more combinations of 4,4'-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (HDI).

[0023] In some embodiments, the silane coupling agent is selected from the group consisting of γ-aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (GPTMS), γ-methacryloxypropyltrimethoxysilane (MPS), vinyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane and isocyanatepropyltrimethoxysilane. One or more combinations thereof.

[0024] In some embodiments, the raw material of the moisture-curing reactive polyurethane hot melt adhesive further includes an auxiliary agent, and the auxiliary agent is selected from a combination of one or more of an antioxidant, a tackifying resin, and a defoaming agent.

[0025] In some embodiments, the antioxidant is selected from a combination of one or more of antioxidant 264 , antioxidant 1076 , and antioxidant 1010 .

[0026] In some embodiments, the tackifying resin is selected from one or more combinations of aldehyde-ketone resins, terpene resins, thermoplastic polyurethane resins TPU, styrene resins, acrylic resins, and rosin resins.

[0027] In some embodiments, the defoaming agent is selected from a combination of one or more of polysiloxane, polyoxyethylene-polyoxypropylene block copolymer, polyoxyethylene fatty acid ester, mineral oil, fatty acid amide, fatty acid ester and phosphate ester.

[0028] In some embodiments, the raw materials of the moisture-curing reactive polyurethane hot melt adhesive include, by weight, 10 to 30 parts of polyester polyol, 30 to 50 parts of polyether polyol, 12 to 16 parts of diisocyanate, 1 to 6 parts of silane coupling agent, 0.5 to 2 parts of antioxidant, 6 to 20 parts of tackifying resin and 0.5 to 2 parts of defoaming agent.

[0029] In some embodiments, the material of the shielding layer is selected from one or more combinations of aluminum foil, copper foil, tin foil, nickel foil, stainless steel foil, nickel-chromium alloy foil and aluminum-magnesium alloy foil.

[0030] In some embodiments, the shielding layer has a thickness of 0.01 to 2 μm.

[0031] Preferably, the thickness of the shielding layer is 0.05-1 μm; more preferably, the thickness of the shielding layer is 0.1-0.8 μm. If the thickness of the shielding layer is too large, when damage such as punching occurs at the construction site of the electric heating film, the excessive amount of material in the damaged metal layer may cause it to not be completely volatilized after melting, and it may still remain between the metal layer and the conductive carbon film layer, resulting in the possibility of a short circuit. The above-mentioned thickness of the present invention can ensure that even if damage such as punching occurs, the shielding layer material that has been melted will be completely volatilized, and the molten hot melt adhesive will cover the shielding layer and the conductive carbon film layer to ensure that the two will not short-circuit, thereby achieving self-repair of the electric heating film.

[0032] In some embodiments, the material of the base film layer is selected from one or more combinations of PVC, PET, PI, PP, and PE.

[0033] In some embodiments, the material of the intermediate film layer is selected from one or more combinations of PVC, PET, PI, PP, and PE.

[0034] In some embodiments, the conductive carbon film layer is formed by an aqueous or oily slurry including a solvent, a conductive phase, a resin, and an additive, wherein the conductive phase is selected from one or more combinations of carbon nanotubes, graphene, carbon fiber, graphite, and conductive carbon black. The solvent may be water or an organic solvent. The resin may be an aqueous resin or an oily resin, and the resin and the additive may be conventional resins and additives in the art.

[0035] In some embodiments, the projection of the electrode layer on the conductive carbon film layer is located on both sides of the conductive carbon film layer, that is, slurry electrodes are arranged on both sides of the conductive carbon film layer.

[0036] In some embodiments, the electrode layer includes a silver paste electrode and a copper foil electrode composited on the silver paste electrode.

[0037] Preferably, the length of the copper foil electrode is equal to the length of the silver paste electrode, and the width of the copper foil electrode is smaller than the width of the silver paste electrode. That is, the copper foil electrode located at the top is narrower than the silver paste electrode located at the bottom. This electrode design can effectively improve the heating efficiency and stability of the electric heating film.

[0038] In some embodiments, the width of the silver paste electrode is 2 to 20 mm.

[0039] In some embodiments, the copper foil electrode has a width of 2 to 20 mm.

[0040] In some embodiments, the thickness of the silver paste electrode is 0.1-5 μm.

[0041] In some embodiments, the copper foil electrode has a thickness of 1 to 100 μm.

[0042] In some embodiments, the electrode layer has a thickness of 10 to 100 μm.

[0043] In some embodiments, the conductive carbon film layer has a thickness of 1 to 100 μm.

[0044] In some embodiments, the material of the current-carrying bar is selected from one or more combinations of aluminum foil, copper foil, tin foil, nickel foil, stainless steel foil, nickel-chromium alloy foil and aluminum-magnesium alloy foil.

[0045] In some embodiments, the width of the bus bar is 4 to 20 mm.

[0046] In some embodiments, the bus bar has a thickness of 1 to 100 μm.

[0047] In some embodiments, the electric heating film further comprises a wiring harness terminal connected to the end of the copper foil electrode, and the ends of the silver paste electrode and the copper foil electrode and the wiring harness terminal are encapsulated and sealed by a hydrophobic polymer. This design can make the connection between the electrode and the wiring harness of the electric heating film more stable, improve the safety of the electric heating film, and at the same time, the use of a hydrophobic polymer for encapsulation and sealing can play a waterproof insulation role, further preventing moisture in the air from penetrating the base film layer to the conductive carbon film layer, thereby improving the waterproofness of the electric heating film.

[0048] The present invention further provides an electric floor heating system comprising the above-mentioned electric heating film.

[0049] The present invention further provides a method for preparing the aforementioned electric heating film, the preparation method comprising the following steps: 1) coating a conductive carbon paste on the base film layer to form the conductive carbon film layer, 2) coating a silver paste electrode and a composite copper foil electrode on the electrode region of the conductive carbon film layer to form an electrode layer, coating a hot melt adhesive on the intermediate film layer, and covering the hot melt adhesive on the conductive carbon film layer containing the electrode layer; 3) coating a hot melt adhesive on the other side of the intermediate film layer, and attaching the shielding layer, compounding a current-carrying bar on the shielding layer, coating a hot melt adhesive on an upper protective layer and compounding it with the shielding layer, 4) coating a hot melt adhesive on the other side of the base film layer and compounding it with a lower protective layer to obtain the electric heating film, the hot melt adhesive containing a moisture-curing reactive polyurethane hot melt adhesive.

[0050] In some embodiments, in step 3), when the hot melt adhesive is coated on the other side of the intermediate film layer, the coating temperature is 100-180° C., and the humidity is controlled to be 40%-90%.

[0051] In some embodiments, in step 4), when applying the hot melt adhesive, the coating temperature is 100-180° C., and the humidity is controlled to be 40%-90%.

[0052] In some embodiments, the preparation method further includes connecting a wiring harness terminal to the end of the copper foil electrode, and forming a hydrophobic polymer on the silver paste, the end of the copper foil electrode and the outside of the wiring harness terminal to perform packaging and sealing.

[0053] Furthermore, the connection of the wiring harness terminals can be achieved through processes such as riveting.

[0054] Furthermore, the molding may be injection molding or the like.

[0055] Furthermore, the hydrophobic polymer may be polyethylene or the like.

[0056] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0057] The electric heating film provided by the present invention has waterproof and shielding layer self-repairing functions. When damage such as drilling occurs at the construction site of the electric heating film, a voltage difference will be generated between the shielding layer and the conductive carbon film layer at the drilling location, resulting in an instantaneous high-temperature arc, which in turn causes the shielding layer at the edge of the drilling to fuse. The present invention arranges a first hot melt adhesive that coats the metal layer in the shielding layer. The hot melt adhesive will partially melt due to the heat generated by the high-temperature arc. The melted adhesive will cover the metal layer and the conductive carbon film layer in the shielding layer, so that the two will no longer short-circuit, and finally the shielding layer self-repairs, so that the electric heating film can still be used normally after damage occurs. Therefore, the service life and use effect of the electric heating film of the present invention can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The schematic diagram of the structure of the electric heating film according to the specific embodiment of the present invention is shown.

[0059] Figure 2 One of the original report figures of the performance test of the electric heating film prepared in Example 1 is shown.

[0060] Figure 3 The second figure of the original report on the performance test of the electric heating film prepared in Example 1 is shown.

[0061] Among them, 1-base film layer, 2-conductive carbon film layer, 3-silver paste electrode, 4-copper foil electrode, 5-first hot melt adhesive layer, 6-intermediate film layer, 7-second hot melt adhesive layer, 8-shielding layer, 9-third hot melt adhesive layer, 10-upper protective layer, 11-fourth hot melt adhesive layer, 12-lower protective layer. DETAILED DESCRIPTION

[0062] If the electric heating film in the existing technology is damaged by drilling or other phenomena at the construction site, it may cause the electric heating film to leak current to the ground, causing safety problems such as leakage protection tripping. After the shielding layer is damaged, it is often impossible to self-repair, and the electric heating film can only be replaced by breaking the ground leveling layer, which will seriously affect the use effect of the electric heating film and electric floor heating system.

[0063] The present invention creatively wraps the traditional shielding layer in a hot melt adhesive layer containing moisture-curing reactive polyurethane hot melt adhesive, so that the upper and lower parts of the shielding layer are all covered with the above-mentioned hot melt adhesive. When damage such as punching occurs at the electric heating film construction site, a voltage difference will be generated between the shielding layer and the conductive carbon film layer at the punching location, resulting in an instantaneous high-temperature arc, which in turn causes the shielding layer at the edge of the punching to fuse. However, the above-mentioned hot melt adhesive will partially melt due to the heat generated by the high-temperature arc, and the melted adhesive will cover the metal layer and the conductive carbon film layer in the shielding layer, so that the two will no longer short-circuit, and finally the shielding layer self-repair will be achieved, so that the electric heating film can still be used normally after being damaged.

[0064] In the electrode layer containing the slurry electrode, the present invention adopts a moisture-curing reactive polyurethane hot melt adhesive, especially a polyurethane hot melt adhesive modified by a silane coupling agent, so as to effectively reduce the probability of moisture in the cement leveling layer passing through the base film layer and the electrode layer into the conductive carbon film layer, thereby reducing the influence of moisture on the resistance of the conductive carbon film layer.

[0065] The present invention arranges a fourth hot melt adhesive layer and a lower protective layer below the base film layer, and adopts moisture-curing reactive polyurethane hot melt adhesive as the fourth hot melt adhesive layer, which can further improve the waterproof performance of the electric heating film and ensure the constant resistance and normal use of the electric heating film.

[0066] The present invention connects the ends of the two sides of the electric heating film electrode (for example, by riveting) with the wiring harness terminal, and then the electrode-terminal-wiring harness connection is encapsulated as a whole (for example, by injection molding polyethylene material). This design can make the connection between the electrode and the wiring harness of the electric heating film more stable, and improve the safety of the electric heating film.

[0067] The present invention is further described below in conjunction with the examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0068] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0069] In the present invention, the terms "upper", "lower" and similar expressions are only for illustrative purposes and do not represent the only implementation method. Figure 1 A specific structural diagram is provided to describe the up and down directions.

[0070] like Figure 1 As shown, the electric heating film includes a lower protective layer 12, a fourth hot melt adhesive layer 11, a base film layer 1, a conductive carbon film layer 2, an electrode layer, a first hot melt adhesive layer 5, an intermediate film layer 6, a second hot melt adhesive layer 7, a shielding layer 8, a third hot melt adhesive layer 9, and an upper protective layer 10, which are arranged in sequence from bottom to top. The electrode layer includes a silver paste electrode 3 and a copper foil electrode 4 located above the silver paste electrode 3. The first hot melt adhesive layer 5, the second hot melt adhesive layer 7, and the third hot melt adhesive layer 9 all contain moisture-curing reactive polyurethane hot melt adhesive.

[0071] Preferably, the silver paste electrode 3 and the copper foil electrode 4 have the same length, but the width of the copper foil electrode 4 is smaller than that of the silver paste electrode 3 .

[0072] The raw materials used in the following examples are all known substances and can be obtained through a variety of combined approaches, one of the common approaches being to purchase from commercial channels.

[0073] The polyester polyol used in the following examples and comparative examples is polypropylene glycol (molecular weight 2000), purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; the polyether polyol is polytetramethylene glycol, purchased from Jiangsu Xinsu New Materials Co., Ltd.

[0074] Example 1

[0075] This embodiment provides an electric heating film, which is prepared by the following method:

[0076] 1) Prepare a PET base film with a size of 50cm*50cm. Evenly coat the aqueous carbon nanotube slurry (composed of 9 parts of multi-walled carbon nanotubes, 3 parts of dispersant, 15 parts of aqueous polyurethane resin, 2 parts of leveling agent, 0.5 parts of defoamer, 0.5 parts of thickener, and 70 parts of deionized water) on the PET base film to form a carbon film coating. In this process, the coating temperature is controlled to be 125°C, the coating time is 2 minutes, and the coating thickness is 5μm.

[0077] 2) Silver paste electrodes were coated on both sides of the carbon film coating, with an electrode width of 8 mm, a coating thickness of 1 μm, and a length of 45 cm. The electrodes were left standing at a high temperature of 150° C. for 0.5 hours to completely dry the silver paste electrodes.

[0078] 3) Coat the PET cover film with PUR hot melt adhesive (by weight, its components are: 25 parts of polyester polyol, 50 parts of polyether polyol, 1 part of 1010 antioxidant, 8 parts of aldehyde-ketone resin, 1 part of polysiloxane defoamer, 12 parts of MDI diisocyanate, 3 parts of silane coupling agent γ-aminopropyl triethoxysilane), control the coating temperature to 150°C, humidity to 70%, coating time to 5 minutes, coating thickness to 15μm, and at the same time, composite copper foil electrode on the silver electrode, the copper foil electrode has a width of 6mm, a length of 45cm, and a thickness of 14 microns. In this process, the PET cover coated with PUR hot melt adhesive is attached to the carbon-coated PET base film, the pressure is 1MPa, and the composite time is 2 minutes.

[0079] 4) Coat the other side of the PET cover film with PUR hot melt adhesive (by weight, its components are: 25 parts of polyester polyol, 50 parts of polyether polyol, 10101 parts of antioxidant, 8 parts of aldehyde-ketone resin, 1 part of polysiloxane defoamer, 12 parts of MDI diisocyanate, 3 parts of silane coupling agent γ-aminopropyl triethoxysilane), and stick the composite aluminum foil shielding layer, the thickness of the aluminum foil is 0.5μm. During the coating process, the coating temperature is controlled to be 150℃, the humidity is 70%, the coating time is 5 minutes, and the coating thickness is 15μm.

[0080] 5) PUR hot melt adhesive (by weight, its components are: 25 parts of polyester polyol, 50 parts of polyether polyol, 10101 parts of antioxidant, 8 parts of aldehyde-ketone resin, 1 part of polysiloxane defoamer, 12 parts of MDI diisocyanate, 3 parts of silane coupling agent γ-aminopropyl triethoxysilane) is coated on the upper and lower layers of the overall membrane structure, and PVC films are attached to each other for overall packaging. During the coating process, the coating temperature is controlled to be 180°C, the humidity is 80%, the coating time is 20 minutes, and the coating thickness is 25 μm.

[0081] 6) Rivet the wire harness terminals on both sides of the electric heating film electrode. The diameter of the wire harness is 2mm and the length is 5cm. During this process, the riveting pressure is controlled to be 1.5MPa and the riveting time is 5 seconds.

[0082] 7) Injection molding is performed on the electrode-terminal-wiring harness connection as a whole, the injection molding material is polyethylene, the injection molding temperature is 220° C., the pressure is 2 MPa, and the injection molding time is 2 minutes to obtain an electric heating film.

[0083] At room temperature, the electric-thermal radiation conversion rate of the electric heating film was tested according to the following test method or test standard: GB / T7287-2008 Infrared Radiation Heater Test Method. The result was 85.9%. The original test report is as follows: Figure 2 shown.

[0084] Perform a perforation test on the heating film (test method as follows Figure 3 The result is that the leakage current before drilling is 1.0586mA, and the leakage current after drilling is 1.0482mA. The difference between the current before and after drilling is very small, and there is no fire phenomenon, which meets the drilling requirements. The original test report is as follows Figure 3 shown.

[0085] The electric heating film was tested for its waterproof performance. The test standard was: GB / T 4208-2017 Enclosure Protection Grade (IP Code). The result was IPX7, which means that the electric heating film has waterproof performance and meets the requirements of the electric heating film waterproof grade.

[0086] It can be seen that the electric heating film of the present invention has waterproof and shielding layer self-repairing capabilities and high electric-thermal radiation conversion efficiency.

[0087] Example 2

[0088] This embodiment provides an electric heating film, which is prepared in the same way as in Example 1, except that the composition of the PUR hot melt adhesive in steps 3)-5) is: 30 parts of polyester polyol, 45 parts of polyether polyol, 0.5 parts of 1010 antioxidant, 9 parts of aldehyde-ketone resin, 0.5 parts of polysiloxane defoamer, 13 parts of MDI diisocyanate, and 2 parts of silane coupling agent γ-aminopropyltriethoxysilane. The coating temperature of step 3) is 160°C, the humidity is 60%, the coating time is 4 minutes, and the coating thickness is 10μm. The thickness of the copper foil electrode is 9μm. In step 4), the thickness of the aluminum foil is 0.8μm, and the coating temperature of step 4) is 160°C, the humidity is 60%, the coating time is 4 minutes, and the coating thickness is 15μm.

[0089] The test results are shown in Table 1 below.

[0090] Example 3

[0091] This embodiment provides an electric heating film, which is prepared in the same manner as in Example 1, except that the composition of the PUR hot melt adhesive in steps 3)-5) is: 20 parts of polyester polyol, 40 parts of polyether polyol, 0.8 parts of 1076 antioxidant, 10 parts of rosin resin, 1 part of polysiloxane defoamer, 14 parts of TDI diisocyanate, and 3 parts of silane coupling agent γ-glycidyloxypropyltrimethoxysilane. In step 4), the thickness of the aluminum foil is 0.3 μm.

[0092] The test results are shown in Table 1 below.

[0093] Example 4

[0094] The present embodiment provides an electric heating film, which is prepared in the same manner as in Embodiment 1, except that the compositions of the PUR hot melt adhesive in steps 3) to 5) are: 25 parts of polyester polyol, 35 parts of polyether polyol, 0.8 parts of 1076 antioxidant, 10 parts of rosin resin, 1 part of polysiloxane defoamer, 16 parts of TDI diisocyanate, and 3 parts of silane coupling agent γ-methacryloxypropyltrimethoxysilane.

[0095] The test results are shown in Table 1 below.

[0096] Comparative Example 1

[0097] This comparative example provides an electric heating film, which is prepared in the same manner as in Example 1, except that the PUR hot melt adhesive in steps 3) to 5) is replaced by commercially available EVA hot melt adhesive.

[0098] The test results are shown in Table 1 below.

[0099] Comparative Example 2

[0100] This comparative example provides an electric heating film, which is prepared in the same manner as in Example 1, except that the PUR hot melt adhesive in steps 3) to 5) is replaced by a commercially available UV light-curing structural adhesive.

[0101] The test results are shown in Table 1 below.

[0102] Comparative Example 3

[0103] This comparative example provides an electric heating film, which is prepared in the same manner as in Example 1, except that the thickness of the aluminum foil in step 4) is replaced with 7 μm.

[0104] Comparative Example 4

[0105] This comparative example provides an electric heating film, which is prepared basically the same as in Example 1, with the only difference being that the PUR hot melt adhesive in steps 3)-4) is replaced by commercially available EVA hot melt adhesive, the shielding layer in step 4) is replaced by copper foil with a thickness of 10 μm, and step 5) is directly performed by laminating PVC films on the upper and lower layers of the overall membrane structure for overall packaging without first applying PUR hot melt adhesive.

[0106] The test results are shown in Table 1 below.

[0107] Table 1

[0108]

[0109] It can be seen that the electric heating film of the present invention has strong waterproof and self-repairing capabilities and a high conversion rate, while the corresponding performance of the electric heating film of the comparative example is significantly reduced.

[0110] The above detailed description of the present invention is intended to enable persons familiar with the technology in this field to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An electric heating film, comprising a base film layer, a conductive carbon film layer, an electrode layer, a first hot melt adhesive layer, an intermediate film layer, a second hot melt adhesive layer, a shielding layer and a third hot melt adhesive layer arranged in sequence from bottom to top, characterized in that: The electrode layer comprises a silver paste electrode region and a copper foil electrode region, and the first hot melt adhesive layer, the second hot melt adhesive layer and the third hot melt adhesive layer all contain moisture-curing reactive polyurethane hot melt adhesive.

2. The electric heating film according to claim 1, characterized in that: The electric heating film also includes a fourth hot melt adhesive layer and a lower protective layer arranged below the base film layer; and / or, the electric heating film also includes an upper protective layer arranged above the third hot melt adhesive layer; and / or, the electric heating film also includes a current-carrying bar arranged between the shielding layer and the third hot melt adhesive layer; preferably, the material of the upper protective layer is selected from a combination of one or more of PVC, PET, PI, PP, and PE, and the material of the lower protective layer is selected from a combination of one or more of PVC, PET, PI, PP, and PE.

3. The electric heating film according to claim 1, characterized in that: The raw materials of the moisture-curing reactive polyurethane hot melt adhesive include polyols, diisocyanates and silane coupling agents, and the polyols are selected from polyether polyols and / or polyester polyols; and / or the melting point range of the moisture-curing reactive polyurethane hot melt adhesive is 110 to 180°C; and / or the thickness of the first hot melt adhesive layer is 10 to 100 μm; and / or the thickness of the second hot melt adhesive layer is 10 to 200 μm; and / or the thickness of the third hot melt adhesive layer is 10 to 200 μm.

4. The electric heating film according to claim 3, characterized in that: In parts by weight, the raw materials of the moisture-curing reactive polyurethane hot melt adhesive include 40 to 80 parts of polyol, 12 to 16 parts of diisocyanate and 1 to 6 parts of silane coupling agent; preferably, in parts by weight, the raw materials of the moisture-curing reactive polyurethane hot melt adhesive include 10 to 30 parts of polyester polyol, 30 to 50 parts of polyether polyol, 12 to 16 parts of diisocyanate and 1 to 6 parts of silane coupling agent; and / or, the diisocyanate is selected from 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, A combination of one or more of isophorone diisocyanate and hexamethylene diisocyanate; and / or, the silane coupling agent is selected from a combination of one or more of γ-aminopropyl triethoxysilane, γ-glycidyloxypropyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane, vinyl triethoxysilane, γ-aminopropyl methyl diethoxysilane, N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane and isocyanate propyl trimethoxysilane.

5. The electric heating film according to any one of claims 1 to 4, characterized in that: The raw materials of the moisture-curing reactive polyurethane hot melt adhesive also include an auxiliary agent, and the auxiliary agent is selected from a combination of one or more of an antioxidant, a tackifying resin and a defoaming agent.

6. The electric heating film according to claim 5, characterized in that: The antioxidant is selected from a combination of one or more of antioxidant 264, antioxidant 1076 and antioxidant 1010; and / or, the tackifying resin is selected from a combination of one or more of aldehyde-ketone resin, terpene resin, thermoplastic polyurethane resin TPU, styrene resin, acrylic resin and rosin resin; and / or, the defoaming agent is selected from a combination of one or more of polysiloxane, polyoxyethylene-polyoxypropylene block copolymer, polyoxyethylene fatty acid ester, mineral oil, fatty acid amide, fatty acid ester and phosphate ester; and / or, in terms of weight parts, the raw materials of the moisture-curing reactive polyurethane hot melt adhesive include 10 to 30 parts of polyester polyol, 30 to 50 parts of polyether polyol, 12 to 16 parts of diisocyanate, 1 to 6 parts of silane coupling agent, 0.5 to 2 parts of antioxidant, 6 to 20 parts of tackifying resin and 0.5 to 2 parts of defoaming agent.

7. The electric heating film according to claim 1, characterized in that: The material of the base film layer is selected from one or more combinations of PVC, PET, PI, PP, and PE; and / or the material of the intermediate film layer is selected from one or more combinations of PVC, PET, PI, PP, and PE.

8. The electric heating film according to claim 1, characterized in that: The conductive carbon film layer is formed by an aqueous or oily slurry including a solvent, a conductive phase, a resin, and an additive, and the conductive phase is selected from one or more combinations of carbon nanotubes, graphene, carbon fibers, graphite, and conductive carbon black.

9. The electric heating film according to claim 1, characterized in that: The projection of the electrode layer on the conductive carbon film layer is located on both sides of the conductive carbon film layer; and / or, the electrode layer includes a silver paste electrode and a copper foil electrode composited on the silver paste electrode; preferably, the length of the copper foil electrode is equal to the length of the silver paste electrode, and the width of the copper foil electrode is smaller than the width of the silver paste electrode.

10. The electric heating film according to claim 9, characterized in that: The width of the silver paste electrode is 2 to 20 mm; and / or, the width of the copper foil electrode is 2 to 20 mm; and / or, the thickness of the silver paste electrode is 0.1 to 5 μm; and / or, the thickness of the copper foil electrode is 1 to 100 μm; and / or, the electric heating film also includes a wiring harness terminal connected to the end of the copper foil electrode, and the ends of the silver paste electrode and the copper foil electrode and the wiring harness terminal are encapsulated and sealed by a hydrophobic polymer.

11. The electric heating film according to claim 1, characterized in that: The material of the shielding layer is selected from one or more combinations of aluminum foil, copper foil, tin foil, nickel foil, stainless steel foil, nickel-chromium alloy foil and aluminum-magnesium alloy foil; and / or the thickness of the shielding layer is 0.01 to 2 μm; preferably, the thickness of the shielding layer is 0.05 to 1 μm; more preferably, the thickness of the shielding layer is 0.1 to 0.8 μm.

12. The electric heating film according to claim 2, characterized in that: The material of the current-carrying bar is selected from one or more combinations of aluminum foil, copper foil, tin foil, nickel foil, stainless steel foil, nickel-chromium alloy foil and aluminum-magnesium alloy foil; and / or the width of the current-carrying bar is 4 to 20 mm; and / or the thickness of the current-carrying bar is 1 to 100 μm.

13. An electric floor heating system, characterized in that: The electric floor heating system comprises the electric heating film according to any one of claims 1 to 12.

14. A method for preparing an electric heating film according to any one of claims 1 to 12, characterized in that: The preparation method comprises the following steps: 1) coating conductive carbon paste on the base film layer to form the conductive carbon film layer; 2) coating silver paste electrode and composite copper foil electrode on the electrode region of the conductive carbon film layer to form an electrode layer; coating hot melt adhesive on the intermediate film layer, and covering the conductive carbon film layer containing the electrode layer with the hot melt adhesive; 3) coating hot melt adhesive on the other side of the intermediate film layer, and attaching the shielding layer, compounding the current-carrying bar on the shielding layer, coating hot melt adhesive on the upper protective layer and compounding it with the shielding layer; 4) coating hot melt adhesive on the other side of the base film layer and compounding it with the lower protective layer to obtain the electric heating film, wherein the hot melt adhesive contains moisture-curing reactive polyurethane hot melt adhesive.

15. The method for preparing the electric heating film according to claim 14, characterized in that: In step 4), when the hot melt adhesive is applied, the coating temperature is 100-180°C and the humidity is controlled at 40%-90%; and / or, in step 3), when the hot melt adhesive is applied on the other side of the intermediate film layer, the coating temperature is 100-180°C and the humidity is controlled at 40%-90%.

16. The method for preparing the electric heating film according to claim 15, characterized in that: The preparation method also includes the steps of connecting a wiring harness terminal to the end of the copper foil electrode, and forming a hydrophobic polymer on the silver paste, the end of the copper foil electrode and the outside of the wiring harness terminal to perform packaging and sealing.

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