A self-temperature-controlled electric heating film and its preparation method and application

Abstract

The present invention provides a self-controlling temperature electric heating film, comprising an insulating isolation layer, interdigitated electrodes arranged on the surface of the insulating isolation layer, a positive temperature coefficient coating covering the surface of the secondary electrode of the interdigitated electrodes, and an insulating protective layer covering the surface of the main electrode of the interdigitated electrodes; the positive temperature coefficient coating does not contact the main electrode of the interdigitated electrodes; the insulating protective layer overlaps the positive temperature coefficient coating. The electric heating film provided by the present invention transfers electrical energy to the positive temperature coefficient (PTC) coating through the interdigitated electrodes when an external voltage is applied, and utilizes its PTC effect to make the coating automatically limit the temperature after being heated to a certain temperature due to the increase in resistance and the decrease in heating power, thereby achieving self-control of temperature and achieving the purpose of anti-deicing. The results of the embodiment show that when the resistivity of the electric heating film of the present invention is 0.01Ω·m, the PTC effect can reach more than 25 times, and the self-controlling temperature effect and droplet sliding performance are good.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric heating films, and in particular relates to a self-temperature-controlling electric heating film and a preparation method and application thereof. Background Art

[0002] Electric heating films have been widely used in many fields, such as heat preservation and heating of equipment or space, and anti-icing of the surface of equipment such as aircraft. The principle of electric heating films is based on Joule's law. By applying a certain voltage to achieve electrothermal heating, the "solid-solid" contact between the surface of the aircraft and the ice can be transformed into a "solid-liquid" contact, thereby reducing the surface ice adhesion and achieving the anti-icing effect. The current electric heating film is mainly sprayed with an electric heating film coating on the surface of the insulating substrate to form an integrated structural functional part. The insulating substrate is generally a structural layer composed of a glass fiber composite layer or a polymer material such as polyetheretherketone. The sprayed electric heating film coating is a metal coating. When the power is turned on and the heat is generated, if there is a covering locally, it is easy to cause local heat accumulation and cause the local temperature to be too high. This heat accumulation will damage the electric heating film, and more seriously, it will cause the covering to burn and cause a fire accident, and then the anti-icing effect cannot be achieved. Therefore, it is necessary to provide an improvement to the electric heating film to achieve self-controlled temperature heating, so as to achieve excellent anti-icing effect. Summary of the invention

[0003] The purpose of the present invention is to provide a self-controlled temperature electric heating film and its preparation method and application. The electric heating film provided by the present invention has a strong PTC effect and can achieve the purpose of electric heating self-controlled temperature and anti-icing when an appropriate voltage is applied.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a self-controlling temperature electric heating film, comprising an insulating isolation layer, interdigitated electrodes arranged on the surface of the insulating isolation layer, a positive temperature coefficient coating covering the surface of the secondary electrode of the interdigitated electrodes, and an insulating protective layer covering the surface of the main electrode of the interdigitated electrodes;

[0006] The positive temperature coefficient coating does not contact the main electrode of the interdigital electrode;

[0007] The insulating protection layer overlaps with the positive temperature coefficient coating.

[0008] Preferably, the positive temperature coefficient coating comprises the following components: 20-40 wt% of nano-conductive filler, 10-30 wt% of positive temperature coefficient thermistor filler, 10-30 wt% of polymer and the balance of phase change material.

[0009] Preferably, the nano conductive filler includes at least one of graphene, conductive carbon black, carbon nanotubes, nano graphite powder, nano metal powder and nano metal wire.

[0010] Preferably, the positive temperature coefficient thermosensitive filler includes at least one of ethylene-vinyl acetate copolymer, positive temperature coefficient ceramic powder, polycaprolactone, biological slice paraffin and thermoplastic polyurethane elastomer.

[0011] Preferably, the phase change material includes at least one of low-temperature lubricating oil, low-temperature lubricating grease and paraffin.

[0012] Preferably, the width of the overlapping portion between the insulating protection layer and the positive temperature coefficient coating is not less than 5 mm.

[0013] Preferably, the insulating protection layer covers a portion of the insulating isolation layer while covering the main electrode of the interdigitated electrode.

[0014] Preferably, the thickness of the insulating isolation layer is 10 to 30 μm; the thickness of the positive temperature coefficient coating is 30 to 90 μm; and the thickness of the insulating protection layer is 10 to 30 μm.

[0015] The present invention also provides a method for preparing the self-controlling temperature electric heating film described in the above technical solution, wherein the insulating isolation layer, the positive temperature coefficient coating and the insulating protection layer are independently prepared by spraying.

[0016] The present invention also provides the use of the self-controlling electric heating film described in the above technical solution or the self-controlling electric heating film prepared by the above technical solution in the field of anti-icing.

[0017] The present invention provides a self-controlling temperature electric heating film, comprising an insulating isolation layer, interdigital electrodes arranged on the surface of the insulating isolation layer, a positive temperature coefficient coating covering the surface of the secondary electrode of the interdigital electrodes, and an insulating protective layer covering the surface of the main electrode of the interdigital electrodes; the positive temperature coefficient coating does not contact the main electrode of the interdigital electrodes; the insulating protective layer overlaps the positive temperature coefficient coating. The electric heating film provided by the present invention comprises an insulating isolation layer, interdigital electrodes arranged on the surface of the insulating isolation layer, a positive temperature coefficient (PTC) coating covering the surface of the secondary electrode of the interdigital electrodes, and an insulating protective layer covering the surface of the main electrode of the interdigital electrodes, but the main electrode of the interdigital electrodes does not contact the PTC coating, so as to avoid excessively high resistance of the main electrode and affect the transmission of electric energy; when an external voltage is applied, the electric energy is first transferred to the secondary electrode through the main electrode of the interdigital electrodes, and then transferred to the PTC coating by the secondary electrode, and the PTC effect is utilized so that the coating will achieve an automatic temperature limiting effect after being heated to a certain temperature due to the increase in resistance and the reduction in heating power, thereby achieving self-controlling temperature performance, thereby achieving the purpose of anti-deicing. The results of the examples show that when the resistivity of the electric heating film provided by the present invention is 0.01 Ω·m, the PTC effect can reach more than 25 times, and the self-temperature control effect and droplet sliding performance are good. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic cross-sectional view of the structure of the self-temperature-controlling electric heating film of the present invention;

[0019] In the figure, 1 is an insulating isolation layer, 2 is an interdigitated electrode, 3 is a positive temperature coefficient coating, and 4 is an insulating protective layer;

[0020] Figure 2 It is a schematic diagram of the top view of the structure of the self-temperature-controlling electric heating film of the present invention;

[0021] In the figure, 2a is the main electrode of the interdigital electrode, 2b is the secondary electrode of the interdigital electrode, 3 is the positive temperature coefficient coating, and 4 is the insulating protective layer;

[0022] Figure 3 The arrangement of the interdigitated electrodes on the insulating isolation layer in Example 2;

[0023] In the figure, 1 is an insulating isolation layer, 2a is a main electrode of the interdigital electrode, and 2b is a secondary electrode of the interdigital electrode;

[0024] Figure 4 This is a schematic diagram of spraying when preparing a positive temperature coefficient coating in Example 2;

[0025] In the figure, A is dispersion liquid 2, B is mask, and C is substrate preheating;

[0026] Figure 5 The relationship curve between the temperature and resistance of the self-controlled electric heating film of Example 2;

[0027] Figure 6 This is an infrared effect diagram of the self-controlling electric heating film of Example 2 from non-heating to heating;

[0028] Figure 7 This is a self-controlling temperature effect diagram of the self-controlling temperature electric heating film of Example 2;

[0029] Figure 8 is the durability performance curve of the self-temperature-controlled electric heating film of Example 2;

[0030] Fig. 9 This is a diagram showing the sliding effect of the self-temperature-controlled electric heating film of Example 2. DETAILED DESCRIPTION

[0031] The present invention provides a self-controlling temperature electric heating film, comprising an insulating isolation layer, interdigitated electrodes arranged on the surface of the insulating isolation layer, a positive temperature coefficient coating covering the surface of the secondary electrode of the interdigitated electrodes, and an insulating protective layer covering the surface of the main electrode of the interdigitated electrodes;

[0032] The positive temperature coefficient coating does not contact the main electrode of the interdigital electrode;

[0033] The insulating protection layer overlaps with the positive temperature coefficient coating.

[0034] like Figure 1 As shown, in the present invention, the self-controlling electric heating film includes an insulating isolation layer 1. In the present invention, the insulating isolation layer is preferably prepared from raw materials including the following components: insulating polymer, organic solvent and thermal insulation functional nanoparticles / thermal conductive functional nanoparticles. In the present invention, the insulating isolation layer mainly plays an insulating protective role, and thermal insulation functional nanoparticles or thermal conductive functional nanoparticles are added according to needs.

[0035] In the present invention, the insulating polymer is preferably at least one of polyurethane, silicone rubber, high-density polyethylene and acrylonitrile-butadiene-styrene copolymer. The present invention has no particular limitation on the source of the insulating polymer, and commercial products well known to those skilled in the art can be used. In the present invention, the insulating polymer plays an insulating role.

[0036] In the present invention, the organic solvent is preferably at least one of toluene, xylene and acetone. The present invention has no particular limitation on the source of the organic solvent, and commercially available products known to those skilled in the art may be used. In the present invention, the organic solvent is used to dissolve the insulating polymer and the thermal insulation functional nanoparticles / thermal conduction functional nanoparticles. In the present invention, the mass ratio of the insulating polymer to the organic solvent is preferably 1:(10-20), more preferably 1:(15-28).

[0037] In the present invention, the heat insulating nanoparticles are preferably hollow glass microspheres and / or aerogel particles; the heat conductive nanoparticles are preferably at least one of cubic boron nitride, nano silicon dioxide and nano aluminum oxide. The present invention does not specifically limit the sources of the heat insulating nanoparticles and the heat conductive nanoparticles, and commercial products known to those skilled in the art can be used. The present invention does not specifically limit the particle size of the heat insulating nanoparticles and the heat conductive nanoparticles, and both submicron and nanometer sizes are possible. In the present invention, the heat insulating nanoparticles play a heat insulating role; the heat conductive nanoparticles play a heat conductive role. If the insulating isolation layer needs to have a heat insulating function, the heat insulating nanoparticles can be added. If the insulating isolation layer needs to have a heat conductive function, the heat conductive nanoparticles can be added. In the present invention, the mass ratio of the insulating polymer to the heat insulating nanoparticles / the heat conductive nanoparticles is preferably 1: (0.5-3), and more preferably 1: (1-2).

[0038] In the present invention, the thickness of the insulating isolation layer is preferably 10 to 30 μm, more preferably 20 to 25 μm.

[0039] like Figure 1As shown, in the present invention, the self-controlled temperature electric heating film includes a forked electrode 2 arranged on the surface of the insulating isolation layer 1. In the present invention, the material of the forked electrode is preferably at least one of metal, carbon fiber and conductive silver glue type conductive polymer; the metal is preferably copper. The present invention has no special restrictions on the sources of the metal material, carbon fiber and conductive silver glue type conductive polymer, and commercial products well known to those skilled in the art can be used. In the present invention, the forked electrode is used for the transmission of electrical energy.

[0040] like Figure 2 As shown, in the present invention, the interdigitated electrode 2 includes a main electrode 2a and an auxiliary electrode 2b; the number of the main electrodes 2a is two, the two main electrodes 2a are distributed in parallel, and a plurality of auxiliary electrodes 2b are equidistantly distributed in parallel between the two main electrodes 2a. The present invention has no special restrictions on the number of auxiliary electrodes 2b and the distance between two adjacent auxiliary electrodes, which can be adjusted according to actual needs. In the present invention, the connection method of the main electrode 2a and the auxiliary electrode 2b is preferably one of metal thermal spraying, metal sputtering, conductive adhesive bonding, solder welding, copper foil engraving and integrated molding. The present invention has no special restrictions on the specific operation of the above-mentioned connection method, and the operation familiar to those skilled in the art can be adopted. In the present invention, the arrangement of the main electrode and the auxiliary electrode in the interdigitated electrode almost eliminates the problem of uneven resistance caused by the PTC effect, so that the heating uniformity is greatly improved.

[0041] like Figure 1 As shown, in the present invention, the self-controlling electric heating film includes a positive temperature coefficient coating 3 covering the surface of the secondary electrode 2b of the interdigital electrode, and the positive temperature coefficient coating 3 does not contact the main electrode 2a of the interdigital electrode. In the present invention, the positive temperature coefficient coating does not contact the main electrode of the interdigital electrode, which can avoid the main electrode resistance being too high and affecting the transmission of electric energy; the positive temperature coefficient coating covers the surface of the secondary electrode of the interdigital electrode, and can transfer the electric energy in the secondary electrode to the positive temperature coefficient (PTC) coating; the PTC coating has its PTC effect, so that after the coating is heated to a certain temperature, the resistance becomes larger and the heating power is reduced, thereby achieving an automatic temperature limiting effect, realizing self-controlling temperature performance, and thus achieving the purpose of anti-deicing.

[0042] like Figure 2 As shown, in one embodiment of the present invention, the positive temperature coefficient coating 3 also covers the portion between the secondary electrodes 2 b on the surface of the insulating isolation layer 1 .

[0043] In the present invention, the positive temperature coefficient coating preferably comprises the following components: 20-40 wt% nano conductive filler, 10-30 wt% positive temperature coefficient thermistor filler, 10-30 wt% polymer and the balance phase change material.

[0044] In the present invention, the positive temperature coefficient coating preferably includes 20-40wt% nano-conductive filler, further preferably 25-35wt%, and more preferably 27-30wt%. In the present invention, the nano-conductive filler preferably includes at least one of graphene, conductive carbon black, carbon nanotubes, nano-graphite powder, nano-metal powder and nano-metal wire, more preferably conductive carbon black and carbon nanotubes; the mass ratio of the conductive carbon black to the carbon nanotubes is preferably 5:1. The present invention has no special limitation on the source of the nano-conductive filler, and commercial products familiar to those skilled in the art can be used. The present invention has no special limitation on the particle size of the nano-conductive filler, and both submicron and nanometer levels are possible. In the present invention, the nano-conductive filler is the above-mentioned substance and the content is within the above-mentioned range to ensure the adjustability of the resistivity.

[0045] In the present invention, the positive temperature coefficient coating preferably includes 10 to 30 wt% of a positive temperature coefficient thermistor filler (PTC filler), more preferably 15 to 25 wt%, and more preferably 17 to 20 wt%. In the present invention, the positive temperature coefficient thermistor filler preferably includes at least one of ethylene-vinyl acetate copolymer, positive temperature coefficient ceramic powder, polycaprolactone, biological slice paraffin and thermoplastic polyurethane elastomer. The present invention has no special limitation on the source of the positive temperature coefficient thermistor filler, and commercially available products familiar to those skilled in the art can be used. The present invention has no special limitation on the particle size of the positive temperature coefficient thermistor filler, and both submicron and nanometer sizes are possible. In the present invention, the positive temperature coefficient thermistor filler is the above-mentioned substance and when the content is within the above-mentioned range, the PTC effect can be further enhanced.

[0046] In the present invention, the positive temperature coefficient coating preferably includes 10 to 30 wt% of polymer, more preferably 15 to 25 wt%, and more preferably 17 to 20 wt%. In the present invention, the polymer preferably includes at least one of silicone rubber, epoxy resin, thermoplastic elastomer, styrene-butadiene rubber and polyurethane. The present invention has no particular limitation on the source of the polymer, and commercial products well known to those skilled in the art can be used. In the present invention, the polymer is a matrix.

[0047] In the present invention, the positive temperature coefficient coating preferably includes a residual phase change material. In the present invention, the phase change material preferably includes at least one of low-temperature lubricating oil, low-temperature grease and paraffin. The present invention has no special limitation on the source of the phase change material, and commercially available products familiar to those skilled in the art can be used. In the present invention, when the phase change material is the above-mentioned substance, it can further adjust the transition temperature of the "solid-liquid" state transition on the surface of the electric heating film, so that it is a liquid-like surface during electric heating, improving the skating performance, and a solid surface at room temperature, improving the anti-fouling ability of the electric heating film.

[0048] In the present invention, the thickness of the positive temperature coefficient coating is preferably 30-90 μm, more preferably 40-80 μm, and more preferably 50-60 μm. In the present invention, the positive temperature coefficient coating can further enhance the PTC effect of the positive temperature coefficient coating when the thickness is within the above range.

[0049] like Figure 1 As shown, in the present invention, the self-controlling temperature electric heating film includes an insulating protective layer 4 covering the surface of the main electrode 2a of the interdigital electrode; the insulating protective layer 4 overlaps the positive temperature coefficient coating 3. In one embodiment of the present invention, the insulating protective layer 4 covers part of the insulating isolation layer 1 while covering the main electrode 2a of the interdigital electrode. In the present invention, the insulating protective layer plays an insulating protection role.

[0050] like Figure 1 As shown, in the present invention, the insulating protection layer 4 overlaps the positive temperature coefficient coating 3 close to the main electrode 2a.

[0051] In one embodiment of the present invention, the width of the overlapped portion between the insulating protective layer 4 and the positive temperature coefficient coating 3 is preferably not less than 5 mm. In the present invention, when the width of the overlapped portion is within the above range, it can ensure that the connection between the main electrode and the auxiliary electrode is not exposed, which affects the performance of the electric heating film.

[0052] In the present invention, the raw material composition for preparing the insulating protection layer is preferably the same as the raw material composition of the insulating isolation layer, which will not be described in detail herein.

[0053] In the present invention, the thickness of the insulating protection layer is preferably 10 to 30 μm, more preferably 15 to 20 μm.

[0054] The electric heating film provided by the present invention includes an insulating isolation layer, interdigitated electrodes arranged on the surface of the insulating isolation layer, a positive temperature coefficient (PTC) coating covering the surface of the secondary electrode of the interdigitated electrodes, and an insulating protective layer covering the surface of the main electrode of the interdigitated electrodes, but the main electrode of the interdigitated electrodes does not contact the PTC coating to avoid excessively high resistance of the main electrode, which affects the transmission of electric energy. When an external voltage is applied, the electric energy is first transferred to the secondary electrode through the main electrode of the interdigitated electrodes, and then transferred to the PTC coating by the secondary electrode. By utilizing its PTC effect, the coating will achieve an automatic temperature limiting effect after being heated to a certain temperature due to the increase in resistance and the reduction in heating power, thereby achieving self-control temperature performance and achieving the purpose of anti-deicing.

[0055] The thickness of the electric heating film provided by the present invention does not exceed 150μm, and it has good flexibility and mechanical strength. The flexibility, wear resistance and other mechanical properties can be adjusted by changing the type and mass ratio of the polymer; the room temperature resistivity is as low as 0.01Ω·m; when the resistivity is 0.01Ω·m, the PTC effect can reach more than 25 times, and the higher the resistivity, the stronger the PTC effect; when an external voltage is applied, it has excellent heat generation uniformity, and realizes electric heating self-control temperature and anti-icing; and the surface of the electric heating film will undergo an obvious "solid-liquid" state transition as the temperature rises, and the droplet sliding performance is significantly enhanced, that is, it is a liquid-like surface during electric heating, which improves the skating performance, and is solid at room temperature, which improves the anti-fouling ability of the sliding surface. It can be applied to aircraft and various types of equipment to achieve self-control temperature and anti-icing, and provides a possibility for the realization of a new "liquid-liquid" electric heating anti-icing technology.

[0056] The present invention sets the PTC coating close to the outer surface, melts the ice on the surface to form a liquid film under the action of electric heating, and forms a "liquid-liquid" interface due to the phase change effect of the phase change material, which greatly improves the anti-icing performance and can reduce the anti-icing temperature and heating power.

[0057] The present invention also provides a method for preparing the self-controlling temperature electric heating film described in the above technical solution, wherein the insulating isolation layer, the positive temperature coefficient coating and the insulating protection layer are independently prepared by spraying.

[0058] In the present invention, the method for preparing the self-temperature-controlled electric heating film preferably comprises the following steps:

[0059] The insulating polymer, the heat-insulating nanoparticles / the heat-conducting nanoparticles and the organic solvent are mixed and sprayed on the substrate, and the insulating isolation layer is obtained after drying;

[0060] Arranging interdigital electrodes on the insulating isolation layer;

[0061] Dissolving nano-conductive fillers, positive temperature coefficient thermistor fillers, polymers and residual phase change materials in an organic solvent, spraying and coating the secondary electrodes covering the interdigitated electrodes, and drying to obtain a positive temperature coefficient coating;

[0062] An insulating polymer, heat-insulating nanoparticles / thermal-conducting nanoparticles and an organic solvent are mixed and sprayed to cover the main electrode and part of the positive temperature coefficient coating of the interdigital electrode, and an insulating protective layer is obtained after drying.

[0063] In the present invention, the insulating polymer, the heat-insulating nanoparticles / the heat-conducting nanoparticles and the organic solvent are preferably mixed and then sprayed on the substrate, and then dried to obtain the insulating isolation layer.

[0064] In the present invention, the insulating polymer, the heat-insulating nanoparticles / thermal-conducting nanoparticles and the organic solvent are preferably mixed under mechanical stirring and ultrasonic conditions; the mixing time is preferably 15 to 30 minutes, more preferably 20 to 25 minutes. The present invention has no special restrictions on the operation of the mechanical stirring and ultrasonic treatment, as long as the mixing is uniform within the above time.

[0065] In the present invention, the spraying of the insulating isolation layer is preferably driven by compressed air. The present invention has no special limitation on the operation of driving by compressed air, and the operation well known to those skilled in the art can be used.

[0066] The present invention has no special limitation on the drying operation, and the drying operation can be performed until constant weight.

[0067] The present invention preferably dissolves nano conductive fillers, positive temperature coefficient thermosensitive fillers, polymers and residual phase change materials in an organic solvent, and then sprays and dries to obtain a positive temperature coefficient coating.

[0068] In the present invention, the organic solvent is preferably the same as the organic solvent used in the aforementioned insulating isolation layer, which will not be described in detail herein. The present invention has no particular limitation on the amount of the organic solvent, as long as it can dissolve all the raw materials.

[0069] In the present invention, the dissolution time is preferably 15 to 30 minutes, more preferably 20 to 25 minutes; the dissolution is preferably carried out under mechanical stirring and ultrasonic conditions. The present invention has no special restrictions on the operation of the mechanical stirring and ultrasonic operation, as long as the mixing is uniform within the above time.

[0070] In the present invention, the spraying of the positive temperature coefficient coating is preferably heated spraying; the heated spraying is preferably preheating the surface to be sprayed; the preheating temperature is preferably 50-60°C, more preferably 55-58°C; the temperature of the mixed solution in the spray gun used for the spraying is preferably 50-60°C, more preferably 55-58°C. In the present invention, when the temperature of the mixed solution in the spray gun and the preheating temperature are within the above range, it can not only prevent the mixed solution from cooling or over-temperature denaturation, but also accelerate the volatilization of the organic solvent.

[0071] In the present invention, the drying is preferably performed by constant temperature heat baking; the constant temperature is preferably 50-60°C, more preferably 55-58°C. In the present invention, constant temperature heat baking is beneficial to complete volatilization of the organic solvent. The present invention has no particular limitation on the drying time, and the measured resistance of the positive temperature coefficient coating is stable.

[0072] In the present invention, the insulating polymer, the heat-insulating nanoparticles / the heat-conducting nanoparticles and the organic solvent are preferably mixed and then sprayed, and then dried to obtain the insulating protective layer.

[0073] In the present invention, the operation of mixing the insulating polymer, the heat insulating functional nanoparticles / the heat conducting functional nanoparticles and the organic solvent is preferably the same as the mixing method of the raw materials in the aforementioned insulating isolation layer, which will not be repeated here.

[0074] In the present invention, the spraying operation is preferably the same as the spraying operation during the preparation of the aforementioned insulating isolation layer, and will not be described in detail herein.

[0075] In the present invention, the drying operation is preferably the same as the drying operation used in the preparation of the aforementioned positive temperature coefficient coating, and will not be described in detail herein.

[0076] The preparation method provided by the invention is simple and feasible and is suitable for industrial production.

[0077] The present invention also provides the use of the self-controlling electric heating film described in the above technical solution or the self-controlling electric heating film prepared by the above technical solution in the field of anti-icing.

[0078] The present invention has no special limitation on the operation of the self-controlling electric heating film in the field of anti-icing, and the operation can be carried out according to conventional electric heating films in the field.

[0079] The self-temperature-controlling electric heating film provided by the present invention has an excellent anti-icing effect in the anti-icing field.

[0080] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a 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 creative work are within the scope of protection of the present invention.

[0081] Example 1

[0082] The structural cross-sectional diagram of the self-temperature-controlled electric heating film provided in this embodiment is as follows Figure 1 As shown, in the figure, 1 is an insulating isolation layer, 2 is an interdigitated electrode, 3 is a positive temperature coefficient coating, and 4 is an insulating protective layer;

[0083] The arrangement of the interdigital electrodes provided in this embodiment on the insulating isolation layer is as follows: Figure 3 As shown in the figure, 1 is an insulating isolation layer, 2a is a main electrode of the interdigital electrode, and 2b is a secondary electrode of the interdigital electrode;

[0084] like Figure 1 and 3As shown, the self-controlling temperature electric heating film is composed of an insulating isolation layer 1, an interdigitated electrode 2 arranged on the surface of the insulating isolation layer 1, a positive temperature coefficient coating 3 covering the surface of the secondary electrode 2b of the interdigitated electrode 2, and an insulating protection layer 4 covering the surface of the main electrode 2a of the interdigitated electrode 1;

[0085] The positive temperature coefficient coating 3 does not contact the main electrode 2a of the interdigital electrode;

[0086] The insulating protection layer 4 overlaps with the positive temperature coefficient coating 3 .

[0087] Example 2

[0088] The structural cross-sectional diagram of the self-temperature-controlled electric heating film provided in this embodiment is as follows Figure 1 As shown, in the figure, 1 is an insulating isolation layer, 2 is an interdigitated electrode, 3 is a positive temperature coefficient coating, and 4 is an insulating protective layer;

[0089] The schematic diagram of the top view of the self-temperature-controlled electric heating film provided in this embodiment is as follows: Figure 2 As shown in the figure, 2a is the main electrode of the interdigital electrode, 2b is the secondary electrode of the interdigital electrode, 3 is the positive temperature coefficient coating, and 4 is the insulating protective layer;

[0090] like Figure 1 and 2 As shown, the self-controlling temperature electric heating film of the present embodiment 2 is composed of an insulating isolation layer 1, an interdigitated electrode 2 arranged on the surface of the insulating isolation layer 1, a positive temperature coefficient coating 3 covering the surface of the secondary electrode 2b of the interdigitated electrode, and an insulating protection layer 4 covering the surface of the main electrode 2a of the interdigitated electrode;

[0091] The positive temperature coefficient coating 3 does not contact the main electrode 2a of the interdigital electrode; the positive temperature coefficient coating 3 also covers the portion between the secondary electrodes 2b on the surface of the insulating isolation layer 1; the insulating protection layer 4 overlaps the positive temperature coefficient coating 3, and the insulating protection layer 4 overlaps the positive temperature coefficient coating 3 close to the main electrode 2a, and the width of the overlapping portion is 5mm; the insulating protection layer 4 covers part of the insulating isolation layer 1 while covering the main electrode 2a of the interdigital electrode;

[0092] The insulating isolation layer has a thickness of 20 μm and is prepared from the following raw materials: polyurethane, xylene and hollow glass microspheres, wherein the mass ratio of polyurethane to organic solvent is 1:10, and the mass ratio of polyurethane to hollow glass microspheres is 1:1;

[0093] The arrangement of the interdigital electrodes provided in this embodiment on the insulating isolation layer is as follows: Figure 3 As shown in the figure, 1 is an insulating isolation layer, 2a is a main electrode of the interdigital electrode, and 2b is a secondary electrode of the interdigital electrode.

[0094] like Figure 3 As shown, the interdigital electrode 2 includes a main electrode 2a and an auxiliary electrode 2b; the number of the main electrodes 2a is two, the two main electrodes 2a are arranged in parallel, and 9 auxiliary electrodes 2b are arranged in parallel between the two main electrodes 2a at an equal interval of 2 cm, wherein the main electrode 2a and the auxiliary electrode 2b are connected by soldering; the material of the interdigital electrode is copper;

[0095] The positive temperature coefficient coating is composed of the following components: 20wt% conductive carbon black and carbon nanotubes (the mass ratio of conductive carbon black to carbon nanotubes is 5:1), 30wt% EVA, 30wt% polyurethane and 20wt% paraffin, with a thickness of 50μm;

[0096] The insulating protective layer has a thickness of 20 μm and is prepared from the following raw materials: polyurethane, xylene and cubic boron nitride, wherein the mass ratio of polyurethane to xylene is 1:10, and the mass ratio of polyurethane to cubic boron nitride is 1:1;

[0097] The preparation method of the self-controlled temperature electric heating film is as follows:

[0098] (1) mixing polyurethane, hollow glass microspheres and xylene under mechanical stirring and ultrasonic conditions for 30 minutes to obtain a dispersion solution 1;

[0099] (2) Spraying the dispersion 1 on the substrate to be sprayed with a spray gun driven by compressed air to obtain an insulating isolation layer after drying;

[0100] (3) On the insulating isolation layer, Figure 3 The interdigitated electrodes are arranged in a manner;

[0101] (4) dissolving the conductive carbon black, carbon nanotubes, EVA, polyurethane and paraffin in xylene under mechanical stirring and ultrasonic conditions for 30 minutes to obtain a dispersion solution 2;

[0102] (5) Use a mask to cover the main electrode and the position 5 mm inward, and spray the dispersion liquid 2 on the insulating isolation layer where the secondary electrode is arranged and the secondary electrode. During the spraying process, the substrate to be sprayed needs to be preheated to 60°C, and the spray gun and the dispersion liquid 2 need to be kept at 60°C; after the spraying is completed, it needs to be heated at a constant temperature of 50°C until the resistance is stable to obtain a positive temperature coefficient coating; the spraying schematic diagram is shown in Figure 4 As shown in the figure, A is the dispersion liquid 2, B is the mask, and C is the substrate preheating; Figure 4 It can be seen that the spraying area needs to be preheated when spraying dispersion liquid II;

[0103] (6) mixing the polyurethane, xylene and cubic boron nitride under mechanical stirring and ultrasonic conditions for 30 minutes to obtain a dispersion solution 3;

[0104] (7) Use a compressed air-driven spray gun to spray the dispersion liquid 3. After spraying, it is necessary to heat bake at a constant temperature of 50°C until the resistance is stable to obtain a self-controlled temperature electric heating film.

[0105] The performance test of the self-controlled temperature electric heating film of Example 2 was carried out, and the results are as follows: Figures 5 to 9 As shown, Figure 5 The relationship curve between the temperature and resistance of the self-controlled electric heating film of Example 2; Figure 6 This is an infrared effect diagram of the self-controlling electric heating film of Example 2 from non-heating to heating; Figure 7 This is a self-controlling temperature effect diagram of the self-controlling temperature electric heating film of Example 2; Figure 8 is the durability performance curve of the self-temperature-controlled electric heating film of Example 2; Fig. 9 The sliding effect diagram of the self-temperature controlling electric heating film of my embodiment 2.

[0106] from Figure 5 It can be seen that the resistance of the electric heating film is highly adjustable.

[0107] from Figure 6 It can be seen that after the electric heating film is electrically heated, the temperature gradually tends to be balanced, which shows that the electric heating film of this embodiment can generate heat uniformly.

[0108] from Figure 7 It can be seen that as the electric heating time increases, the power of the electric heating film first decreases rapidly and then tends to be stable and finally remains unchanged, while the temperature first increases rapidly and then tends to be stable, which shows that the electric heating film provided in this embodiment has self-temperature control performance.

[0109] from Figure 8 It can be seen that each curve represents a different number of heating times. It can be seen that after the electric heating film is heated multiple times, its PTC performance is still very stable, indicating that the electric heating film provided in this embodiment has excellent durability.

[0110] from Fig. 9 It can be seen that as time goes by, the ice layer on the surface of the electric heating film gradually melts and moves downward, and obvious slip occurs at 0.14ms. At 0.27ms, the ice layer has completely melted to form droplets, indicating that the electric heating film of this embodiment has good droplet slip performance.

[0111] It can be seen from the above embodiments that the electric heating film provided by the present invention has a strong PTC effect and can achieve the purpose of electric heating self-temperature control and anti-icing when a proper voltage is applied.

[0112] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A self-controlled temperature electric heating film, comprising an insulating isolation layer, an interdigitated electrode arranged on the surface of the insulating isolation layer, a positive temperature coefficient coating covering the surface of the secondary electrode of the interdigitated electrode, and an insulating protective layer covering the surface of the main electrode of the interdigitated electrode; The positive temperature coefficient coating does not contact the main electrode of the interdigital electrode; The insulating protective layer overlaps with the positive temperature coefficient coating; The positive temperature coefficient coating is composed of the following components: 20-40wt% nano conductive filler, 10-30wt% positive temperature coefficient thermistor filler, 10-30wt% polymer and the balance phase change material; The nano conductive filler is at least one of graphene, conductive carbon black, carbon nanotubes, nano graphite powder, nano metal powder and nano metal wire; The positive temperature coefficient thermosensitive filler is at least one of ethylene-vinyl acetate copolymer, positive temperature coefficient ceramic powder, polycaprolactone, biological slice paraffin and thermoplastic polyurethane elastomer; The phase change material is at least one of low temperature lubricating oil, low temperature lubricating grease and paraffin.

2. The self-temperature-controlled electric heating film according to claim 1, characterized in that: The width of the overlapping portion between the insulating protection layer and the positive temperature coefficient coating is not less than 5 mm.

3. The self-temperature-controlled electric heating film according to claim 1, characterized in that: The insulating protection layer covers a portion of the insulating isolation layer while covering the main electrode of the interdigitated electrode.

4. The self-temperature-controlled electric heating film according to claim 1, characterized in that: The thickness of the insulating isolation layer is 10 to 30 μm; the thickness of the positive temperature coefficient coating is 30 to 90 μm; and the thickness of the insulating protection layer is 10 to 30 μm.

5. The method for preparing the self-temperature-controlled electric heating film according to any one of claims 1 to 4, characterized in that: The insulating isolation layer, the positive temperature coefficient coating and the insulating protection layer are prepared by spraying.

6. Use of the self-controlling electric heating film according to any one of claims 1 to 4 or the self-controlling electric heating film prepared by the preparation method of claim 5 in the field of anti-icing.

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