Flexible metal film electric heating assembly and preparation method thereof

Abstract

The invention relates to the technical field of electric heating, in particular to a flexible metal film electric heating assembly and a preparation method thereof. The invention provides a preparation method of a flexible metal film electric heating assembly, which comprises the following steps: forming a metal transition layer on the surface of one side of a first flexible substrate film, and then forming a metal film layer on the surface of the metal transition layer to obtain an electric heating functional layer; wherein in the process of forming the metal transition layer, an infrared radiation heater is used for heating one side of the first flexible base material film; an infrared radiation heater is used for heating one side of the first flexible base material film in the process of forming the metal film layer; through subsequent steps, the flexible electric heating assembly which is stable in resistance control, uniform in electric heating and high in reliability is obtained.

Description

Technical Field

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

[0002] Flexible heaters are thin flexible heating elements that are easily fixed to objects and transfer heat energy to objects to promote antifreeze, temperature maintenance, humidity control or thermal control, regulation, etc. The heating functional layer of existing flexible electric heaters is mainly a metal resistance wire or etched alloy foil with a densely spaced line pattern design (for example, etched stainless steel, NiCr foil or copper alloy and other alloy foils, with a foil thickness of ≥12um). Due to the reasons that the spacing area of ​​the pattern cannot generate heat and the thickness of the metal foil is too thick, this type of flexible electric heater has always had problems with electric heating uniformity and long-term reliability. Another design of the electric heating functional layer is a conductive ink (containing conductive nanoparticles or graphene nanosheets and resin) coating. Due to the presence of resin and the influence of subsequent hot pressing processing, the control of the surface resistance or square resistance of the electric heating functional layer is extremely unstable, making it difficult to be widely used in the industry. There are also reports that a transparent conductive metal oxide film (film thickness <1um, such as ITO, AZO, ATO and other films) is sputtered on automobile glass or PET substrate to achieve electric heating; this type of electric heating film is affected by the brittleness or cracking of the ITO film, as well as the deterioration of the bonding strength between the film and the substrate under long-term high temperature environment. The reliability of the prepared flexible heater is difficult to meet industrial design requirements.

[0003] In summary, there is an urgent need in the prior art to develop a flexible electric heating component that has stable resistance control, uniform electric heating, and high reliability. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the lack of a flexible electric heating component in the prior art that has the performance of stable resistance control, uniform electric heating, and high reliability, thereby providing a flexible metal film electric heating component and a preparation method thereof.

[0005] The present invention provides a method for preparing a flexible metal film electric heating component, comprising the following steps:

[0006] (1) forming a metal transition layer on one side of a first flexible substrate film, and then forming a metal thin film layer on the surface of the metal transition layer to obtain an electric heating functional layer; wherein, in the process of forming the metal transition layer, an infrared radiation heater is used to heat the side of the first flexible substrate film on which the metal transition layer is to be formed; and / or, in the process of forming the metal thin film layer, an infrared radiation heater is used to heat the side of the first flexible substrate film close to the metal transition layer;

[0007] (2) forming a semi-cured thermosetting resin layer on one surface of the copper foil, then laminating a second flexible substrate film on the surface of the thermosetting resin layer, then etching the copper foil to form a copper electrode layer, and coating a conductive adhesive layer on the surface of the copper electrode layer to obtain an electrode functional layer;

[0008] (3) Laminating, hot pressing, baking and laser drilling the electric heating functional layer and the electrode functional layer, and then forming a first insulating protective layer on the surface of the first flexible substrate film away from the metal transition layer, and forming a second insulating protective layer on the surface of the second flexible substrate film away from the copper electrode layer, and then laminating, hot pressing, baking and curing the first insulating protective layer and the second insulating protective layer to obtain the flexible metal film electric heating component; wherein, the process of laminating the electric heating functional layer and the electrode functional layer is to laminate the conductive adhesive layer and the metal film layer.

[0009] Preferably, in step (1), the method for forming the metal transition layer is magnetron sputtering with a bias voltage design in a PVD process.

[0010] Preferably, in step (1), the method of forming the metal thin film layer is at least one of sputtering and evaporation deposition in a PVD process.

[0011] Preferably, the metal ion concentration in the metal transition layer is in the range of 5×10 15 -8.0×10 17 atoms / cm 2 ;

[0012] Preferably, the thickness of the metal transition layer and the metal film layer is 0.1-1 μm in total;

[0013] Preferably, the sheet resistance of the metal film layer is 1-350Ω / sq.

[0014] Preferably, the infrared radiation heater is a graphene heater, wherein the graphene in the graphene heater is a heating layer, the graphene is a layered nanostructured film prepared by a graphene oxide reduction method or a CVD process, and the heating temperature range of the graphene heater is less than or equal to 200°C.

[0015] Preferably, the materials of the metal transition layer and the metal film layer are selected from nickel-based alloys and / or copper-nickel alloys.

[0016] Preferably, the nickel-based alloy includes nickel-chromium alloy, nickel-chromium-aluminum-iron alloy, nickel-chromium-manganese-silicon alloy, and nickel-manganese-chromium-molybdenum alloy;

[0017] Preferably, the copper foil has a thickness of 12 μm-35 μm; and / or,

[0018] The thickness of the semi-cured thermosetting resin layer is 5 μm-100 μm; and / or,

[0019] The relative curing degree of the semi-solid state heat-curing resin layer is 40%-80%; and / or, the electrode spacing in the copper electrode layer is 10mm-200mm; and / or,

[0020] The length of the electrodes in the copper electrode layer is 10 mm to 500 mm.

[0021] The relative degree of curing of the semi-solidified thermosetting resin layer can be measured using differential scanning calorimetry (DSC) or TMA.

[0022] Preferably, the material of the first flexible substrate film is selected from polyimide film or polyethylene terephthalate film;

[0023] The thickness of the first flexible substrate film is 10 μm-50 μm; and / or,

[0024] The material of the second flexible substrate film is selected from polyimide film or polyethylene terephthalate film; and / or,

[0025] The thickness of the second flexible substrate film is 10 μm-100 μm; and / or,

[0026] The initial material of the semi-solid state thermosetting resin layer includes at least one of epoxy resin, acrylic adhesive, and fluorine-containing thermosetting resin; the material of the conductive adhesive layer is a mixture of conductive particles and thermosetting resin.

[0027] Preferably, the first insulating protective layer and the second insulating protective layer are made of a material selected from polyimide film;

[0028] Preferably, a first heat-curing layer is further included between the first insulating protective layer and the first flexible substrate film; the material of the first heat-curing layer is selected from modified epoxy resin or acrylic glue;

[0029] Preferably, a second heat-curing layer is further included between the second insulating protective layer and the second flexible substrate film; the material of the second heat-curing layer is selected from modified epoxy resin or acrylic adhesive.

[0030] The present invention also provides a flexible metal film electric heating component, which is prepared by the above-mentioned preparation method.

[0031] The present invention also provides a flexible metal film electric heating component prepared by the above-mentioned preparation method or the application of the above-mentioned flexible metal film electric heating component in structural elements of spacecraft onboard equipment, structural elements of sea, land and air transportation vehicles, vacuum devices, space suits, infrared thermal therapy chambers, automotive battery thermal management equipment, automotive seat heating equipment, and household floor heating equipment.

[0032] The technical solution of the present invention has the following advantages:

[0033] The method for preparing the flexible metal film electric heating component provided by the present invention comprises the following steps:

[0034] (1) forming a metal transition layer on one side of a first flexible substrate film, and then forming a metal thin film layer on the surface of the metal transition layer to obtain an electric heating functional layer; wherein, in the process of forming the metal transition layer, an infrared radiation heater is used to heat the side of the first flexible substrate film on which the metal transition layer is to be formed; and / or, in the process of forming the metal thin film layer, an infrared radiation heater is used to heat the side of the first flexible substrate film close to the metal transition layer; (2) forming a semi-cured thermosetting resin layer on the surface of one side of a copper foil, and then laminating a second flexible substrate film on the surface of the thermosetting resin layer, and then etching the copper foil to form a copper electrode layer, and (3) laminating, hot pressing, baking and laser drilling the electric heating functional layer and the electrode functional layer to adjust the resistance, then forming a first insulating protective layer on the surface of the first flexible substrate film away from the metal transition layer, and forming a second insulating protective layer on the surface of the second flexible substrate film away from the copper electrode layer, and then laminating, hot pressing, baking and curing the first insulating protective layer and the second insulating protective layer to obtain the flexible metal film electric heating component; wherein, the process of laminating the electric heating functional layer and the electrode functional layer is to laminate the conductive adhesive layer and the metal film layer.

[0035] The present invention provides that the process of forming a metal transition layer and a metal film layer is carried out under an infrared radiation heater. The infrared radiation heater has the advantages of a large heating area, relatively uniform heating, and a relatively fast heating temperature rise rate. This is beneficial in the process of forming the metal transition layer and the metal film layer, and the resistance of the metal film is stably controlled, the bonding strength of the metal film and the flexible substrate is improved, and the reliability is improved (compared with the bonding strength of the metal film and the flexible substrate without heating or using traditional resistance heating, the bonding strength can be improved by at least 10%), and the problem of bubbles or stratification occurring in the flexible metal film electric heating component at high temperature is reduced.

[0036] Furthermore, a metal transition layer is formed by a sputtering process with a bias voltage design. The metal transition layer obtained by this method interacts with the metal film layer, which can further improve the bonding strength of the obtained metal film layer, and is also beneficial to the thickness uniformity of the metal film layer and the uniform electrically heated heating layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 is a preparation flow chart in an embodiment of the present invention;

[0039] Figure 2-8 is a schematic diagram of forming a flexible metal film electric heating assembly in an embodiment of the present invention;

[0040] Description of reference numerals:

[0041] 101, first flexible substrate film; 102, metal transition layer; 103, metal film layer; 104, conductive adhesive layer; 100, electric heating functional layer; 201, copper foil; 202, thermosetting resin layer; 203, second flexible substrate film; 204, copper electrode layer; 205, electrical adhesive layer; 200, electrode functional layer; 300, first insulating protective layer; 302, polyimide layer; 301, semi-cured resin layer; 400, second insulating protective layer; 402, polyimide layer, 401, semi-cured resin layer. DETAILED DESCRIPTION

[0042] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0043] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0044] Example

[0045] This embodiment provides a method for preparing a flexible metal film electric heating component. Figure 1 , including the following steps:

[0046] (1) forming a metal transition layer on one side of a first flexible substrate film, and then forming a metal thin film layer on the surface of the metal transition layer to obtain an electric heating functional layer; wherein, in the process of forming the metal transition layer, an infrared radiation heater is used to heat the side of the first flexible substrate film on which the metal transition layer is to be formed; and / or, in the process of forming the metal thin film layer, an infrared radiation heater is used to heat the side of the first flexible substrate film close to the metal transition layer;

[0047] (2) forming a semi-cured thermosetting resin layer on one surface of the copper foil, then laminating a second flexible substrate film on the surface of the thermosetting resin layer, then etching the copper foil to form a copper electrode layer, and coating a conductive adhesive layer on the surface of the copper electrode layer to obtain an electrode functional layer;

[0048] (3) Laminating, hot pressing, baking and laser drilling the electric heating functional layer and the electrode functional layer, and then forming a first insulating protective layer on the surface of the first flexible substrate film away from the metal transition layer, and forming a second insulating protective layer on the surface of the second flexible substrate film away from the copper electrode layer, and then laminating, hot pressing, baking and curing the first insulating protective layer and the second insulating protective layer to obtain the flexible metal film electric heating component; wherein, the process of laminating the electric heating functional layer and the electrode functional layer is to laminate the conductive adhesive layer and the metal film layer.

[0049] Reference below Figure 2-8 Provide detailed explanation.

[0050] refer to Figure 2 A metal transition layer 102 is formed on one surface of the first flexible substrate film 101 , and then a metal film layer 103 is formed on the surface of the metal transition layer 102 to obtain an electric heating functional layer 100 .

[0051] In one embodiment, a uniformly distributed metal transition layer 102 is formed by using an alloy target and a magnetron sputtering process with a bias voltage design, wherein the concentration of metal ions in the magnetron sputtering in the metal transition layer 102 is in the range of 5×10 15 -8.0×10 17 atoms / cm 2 ; In the process of forming the metal transition layer 102, an infrared radiation heater is used to heat the side of the first flexible substrate film 101 on which the metal transition layer 102 is to be formed;

[0052] In one embodiment, the method of forming the metal film layer 103 is at least one of sputtering deposition and evaporation deposition in the PVD process; during the process of forming the metal film layer 103, an infrared radiation heater is also used to heat the side close to the metal transition layer 102;

[0053] The metal film layer 103 formed in the present invention is resistant to high temperature, oxidation and corrosion.

[0054] In a specific embodiment, the total thickness of the metal film layer 103 and the metal transition layer 102 is 0.1-1 μm; for example, 0.1 μm, 0.11 μm, 0.13 μm, 0.15 μm or 1 μm.

[0055] In a specific embodiment, the total square resistance of the metal transition layer 102 and the metal thin film layer 103 is 1-350Ω / sq; for example, 1Ω / sq, 5Ω / sq, 10Ω / sq, 100Ω / sq, 300Ω / sq or 350Ω / sq.

[0056] In one embodiment, the infrared radiation heater is a graphene heater, wherein the graphene in the graphene heater is a heating layer, and the graphene is a layered nanostructured film prepared by a graphene oxide reduction method or a CVD process, and the heating temperature range of the graphene heater is less than or equal to 200°C; for example: 50°C, 100°C, 150°C or 200°C.

[0057] In a specific embodiment, the material of the metal transition layer 102 is selected from nickel-based alloys and / or copper-nickel alloys; wherein the nickel-based alloys include at least one of nickel-chromium alloys, nickel-chromium-aluminum-iron alloys, nickel-chromium-manganese-silicon alloys, and nickel-manganese-chromium-molybdenum alloys;

[0058] In a specific embodiment, the material of the metal film layer 103 is selected from nickel-based alloys and / or copper-nickel alloys; wherein the nickel-based alloys include at least one of nickel-chromium alloys, nickel-chromium-aluminum-iron alloys, nickel-chromium-manganese-silicon alloys, and nickel-manganese-chromium-molybdenum alloys.

[0059] In a specific embodiment, the material of the first flexible substrate film 101 is selected from polyimide film or polyethylene terephthalate film;

[0060] In a specific embodiment, the thickness of the first flexible substrate film 101 is 10-50 μm, such as 10 μm, 20 μm, 30 μm, 40 μm or 50 μm.

[0061] refer to Figure 3 A semi-cured thermosetting resin layer 202 is formed on one side of the copper foil 201, and then a second flexible substrate film 203 is attached to the surface of the thermosetting resin layer 202. Then, the copper foil 201 is etched using a conventional PCB wet etching process to form a copper electrode layer 204, and a conductive adhesive layer 205 is coated on the surface of the copper electrode layer 204 to obtain an electrode functional layer 200 (reference Figure 5 ).

[0062] In a specific embodiment, the copper foil 201 has a thickness of 12-35 μm, for example, 12 μm, 20 μm or 35 μm.

[0063] In a specific embodiment, the thickness of the semi-cured thermosetting resin layer 202 is 5-100 μm, for example, 5 μm, 10 μm, 20 μm, 50 μm or 90 μm.

[0064] In a specific embodiment, the relative curing degree of the semi-solid state heat-curing resin layer 202 is 40-80%. ；

[0065] In a more specific embodiment, the initial material of the semi-solid state heat-curable resin layer 202 is selected from but not limited to at least one of epoxy resin, acrylic adhesive, and fluorine-containing heat-curable resin; wherein the epoxy resin includes epoxy-modified resin.

[0066] The relative degree of curing of the semi-solidified thermosetting resin layer can be measured using differential scanning calorimetry (DSC) or TMA.

[0067] In a specific embodiment, the material of the second flexible substrate film 203 is selected from polyimide film or polyethylene terephthalate film;

[0068] In a specific embodiment, the thickness of the second flexible substrate film 203 is 10 μm-100 μm, such as 10 μm, 20 μm, 30 μm, 50 μm, 80 μm or 100 μm.

[0069] In a specific embodiment, the electrode spacing in the copper electrode layer 204 is 10 mm-200 mm, such as 10 mm, 50 mm, 100 mm, 150 mm or 200 mm;

[0070] In a specific embodiment, the length of the electrodes in the copper electrode layer 204 is 10 mm-500 mm, such as 10 mm, 100 mm, 200 mm, 300 mm, 400 mm or 500 mm.

[0071] In a more specific embodiment, after forming the copper electrode layer 204 , a process of inserting a wire into the end of the electrode is also included.

[0072] In one embodiment, the conductive adhesive layer 205 is formed by screen printing.

[0073] In a specific embodiment, the thickness of the conductive adhesive layer 205 is 5 μm-50 μm; for example:

[0074] In a specific embodiment, the material of the conductive adhesive layer 104 is a mixture of conductive particles and thermosetting resin, wherein the conductive particles are selected from but not limited to silver, nickel, copper, titanium or carbon nanosheets; wherein the thermosetting resin is selected from modified epoxy resin, epoxy modified or fluorine-containing resin, etc.; the mass ratio of the conductive particles to the thermosetting resin is (50-99.5): (0.5-50).

[0075] refer to Figure 6 , the electric heating functional layer 100 and the electrode functional layer 200 are laminated, hot pressed and baked.

[0076] refer to Figure 7 , the resistance of the electric heating function layer 100 and the electrode function layer 200 after hot pressing and baking is adjusted by laser drilling.

[0077] In a specific embodiment, the resistance adjustment is achieved by forming a through hole through laser drilling.

[0078] refer to Figure 8 ,exist Figure 7 The first insulating protective layer 300 is formed on the basis of the first flexible substrate film 101 . The process of forming the first insulating protective layer 300 is to laminate, bond and hot-press the first insulating protective layer 300 on the surface of the first flexible substrate film 101 away from the metal transition layer 102 .

[0079] In a specific embodiment, the first insulating protective layer 300 is a traditional covering film material, including a polyimide layer 302 and a semi-cured resin layer 301; its main manufacturing process is to apply thermosetting glue on the polyimide film 302 and bake to form the semi-cured resin layer 301 material.

[0080] Continue to refer Figure 8 ,exist Figure 7 The second insulating protective layer 400 is formed on the basis of the second flexible substrate film 203, and the process of forming the second insulating protective layer 400 is to laminate and hot-press the second insulating protective layer 400 on the surface of the second flexible substrate film 203 away from the copper electrode layer 204. The second insulating protective layer 400 is also a traditional covering film material, including a polyimide layer 402 and a semi-cured resin layer 401;

[0081] In one embodiment, after forming the second insulating protection layer 400, Figure 8 The obtained structure is baked until it is completely cured, wherein the baking temperature is 100-200° C. and the baking time is 0.5-3 hours.

[0082] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a flexible metal film electric heating component, characterized in that: The steps include: (1) forming a metal transition layer on one side of a first flexible substrate film, and then forming a metal thin film layer on the surface of the metal transition layer to obtain an electric heating functional layer; wherein, in the process of forming the metal transition layer, an infrared radiation heater is used to heat the side of the first flexible substrate film on which the metal transition layer is to be formed; and / or, in the process of forming the metal thin film layer, an infrared radiation heater is used to heat the side of the first flexible substrate film close to the metal transition layer; (2) forming a semi-cured thermosetting resin layer on one surface of the copper foil, then laminating a second flexible substrate film on the surface of the thermosetting resin layer, then etching the copper foil to form a copper electrode layer, and coating a conductive adhesive layer on the surface of the copper electrode layer to obtain an electrode functional layer; (3) Laminating, hot pressing, baking and laser drilling the electric heating functional layer and the electrode functional layer, and then forming a first insulating protective layer on the surface of the first flexible substrate film away from the metal transition layer, and forming a second insulating protective layer on the surface of the second flexible substrate film away from the copper electrode layer, and then laminating, hot pressing, baking and curing the first insulating protective layer and the second insulating protective layer to obtain the flexible metal film electric heating component; wherein, the process of laminating the electric heating functional layer and the electrode functional layer is to laminate the conductive adhesive layer and the metal film layer.

2. The preparation method according to claim 1, characterized in that: In step (1), the method for forming the metal transition layer is magnetron sputtering with a bias voltage design in a PVD process; and / or, In step (1), the method of forming the metal thin film layer is at least one of sputtering and evaporation deposition in the PVD process.

3. The preparation method according to claim 2, characterized in that: The concentration range of the metal ions formed by magnetron sputtering in the metal transition layer is 5×10 15 -8.0×10 17 atoms / cm 2 ; Preferably, the thickness of the metal transition layer and the metal film layer is 0.1 μm-1 μm in total; Preferably, the sheet resistance of the metal film layer is 1-350Ω / sq.

4. The preparation method according to claim 1, characterized in that: The infrared radiation heater is a graphene heater, wherein the graphene in the graphene heater is a heating layer, the graphene is a layered nanostructured film prepared by a graphene oxide reduction method or a CVD process, and the heating temperature range of the graphene heater is less than or equal to 200°C.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The materials of the metal transition layer and the metal film layer are selected from nickel-based alloys and / or copper-nickel alloys; Preferably, the nickel-based alloy includes at least one of nickel-chromium alloy, nickel-chromium-aluminum-iron alloy, nickel-chromium-manganese-silicon alloy and nickel-manganese-chromium-molybdenum alloy.

6. The preparation method according to any one of claims 1 to 4, characterized in that: The copper foil has a thickness of 12 μm to 35 μm; and / or, The thickness of the semi-cured thermosetting resin layer is 5 μm-100 μm; and / or, The relative curing degree of the semi-solid state heat-curing resin layer is 40%-80%. ； and / or, The electrode spacing in the copper electrode layer is 10 mm to 200 mm; and / or, The length of the electrodes in the copper electrode layer is 10 mm to 500 mm.

7. The preparation method according to any one of claims 1 to 4, characterized in that: The material of the first flexible substrate film is selected from polyimide film or polyethylene terephthalate film; The thickness of the first flexible substrate film is 10 μm-50 μm; and / or, The material of the second flexible substrate film is selected from polyimide film or polyethylene terephthalate film; and / or, The thickness of the second flexible substrate film is 10 μm-100 μm; and / or, The initial material of the semi-solid state thermosetting resin layer includes at least one of epoxy resin, acrylic adhesive, and fluorine-containing thermosetting resin; the material of the conductive adhesive layer is a mixture of conductive particles and thermosetting resin.

8. The preparation method according to any one of claims 1 to 4, characterized in that The materials of the first insulating protective layer and the second insulating protective layer are selected from polyimide films; Preferably, a first heat-curing layer is further included between the first insulating protective layer and the first flexible substrate film; the material of the first heat-curing layer is selected from epoxy resin or acrylic glue; Preferably, a second heat-curing layer is further included between the second insulating protective layer and the second flexible substrate film; and the material of the second heat-curing layer is selected from epoxy resin or acrylic adhesive.

9. A flexible metal film electric heating component, characterized in that: The preparation method is described in any one of claims 1 to 8.

10. Application of a flexible metal film electric heating component prepared by the preparation method according to any one of claims 1 to 8 or the flexible metal film electric heating component according to claim 9 in structural elements of spacecraft onboard equipment, structural elements of sea, land and air transportation vehicles, vacuum devices, space suits, infrared thermal therapy cabins, automotive battery thermal management equipment, automotive seat heating equipment, and household floor heating equipment.

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