Bending-resistant insulating hot-pressed film for liquid cooling plate and preparation method of bending-resistant insulating hot-pressed film

Abstract

The invention discloses a bending-resistant insulating hot-pressed film for a liquid cooling plate and a preparation method of the bending-resistant insulating hot-pressed film. The insulating hot-pressed film comprises a first adhesive layer, an insulating base film layer, a second adhesive layer and a hot melt adhesive layer which are sequentially stacked. According to the insulating hot-pressing film provided by the invention, the adhesive layer is formed through double-sided coating, so that the hot melt adhesive layer and the insulating film are more firmly adhered together, and the adhesive force of the hot melt adhesive and the insulating film can be improved when the liquid cooling plate is wrapped in an overlapping manner; the hot melt adhesive layer is an adhesive layer modified by a formula, so that the bonding force between the hot melt adhesive layer and the liquid cooling plate can be greatly enhanced, the hot melt adhesive layer has excellent high temperature resistance, and the hot melt adhesive layer can still have very high bonding force with the liquid cooling plate after an aging test; the extrusion and drawing deformation force on the adhesive film when the liquid cooling plate is bent and deformed can be resisted by improving the bonding force of the hot melt adhesive and matching and combining the bending-resistant base material, so that layering and bubbles are avoided.

Description

Technical Field

[0001] The invention relates to the field of liquid cooling plate insulation films, and in particular to a bending-resistant insulation hot-pressed film for a liquid cooling plate and a preparation method thereof. Background Art

[0002] With the development of global automobiles, especially the rise and rapid development of new energy vehicles, the integration requirements of power batteries are getting higher and higher, which brings many conveniences to the promotion and use of new energy vehicles. However, integrated batteries will inevitably generate a lot of heat when working. Generally speaking, the higher the degree of integration, the greater the heat generated during operation. The temperature will directly affect the working efficiency of the battery. If the heat cannot be dissipated in time and quickly accumulates inside the battery, the battery may also leak, deflate, smoke, etc. In severe cases, it may burn or explode, affecting battery safety.

[0003] Liquid cooling plate, also called water cooling plate, is one of the most critical components in the liquid cooling system of battery pack in new energy vehicles. At present, most of the square battery liquid cooling systems use module-level water cooling plates, which are generally placed at the bottom of the battery box; for soft pack battery liquid cooling, most of them are in the form of integrating small water cooling plates inside the module, and there are also forms in which aluminum plates are integrated in the module and module-level liquid cooling plates are set outside the module; for cylindrical batteries, the serpentine tube led by Tesla is the main form of liquid cooling radiator, refer to its patent US20110212356A1.

[0004] There are not many products on the market related to liquid cooling plate heat dissipation insulation materials. The main products in the existing technology are:

[0005] 1) Apply pressure-sensitive adhesive material on the insulating film, and use tape to wrap and bond the liquid cooling plate at room temperature. Figure 2 This product is suitable for straight liquid cooling plates, but when the liquid cooling plate is extruded into a serpentine shape, the contact part between the glue and the insulating film is easy to delaminate and form bubbles. The overlapping part of the tape is not flexible enough due to insufficient adhesion, and it is also easy for the liquid cooling plate to bend and deform to generate extrusion and pulling force, resulting in delamination. Figure 3 . In addition, the heat resistance reliability is poor, and the high temperature adhesion at 85°C is only a few grams, which is easy to fall off during the use of the liquid cooling plate. This type of product is sub-sensitive at room temperature, so a release film needs to be added, which increases the cost. During the use of the client, the protective film needs to be removed, which increases the process.

[0006] 2) The insulating film is coated with hot pressing structural adhesive, and then hot pressing and curing is performed. The hot pressing time is 2 to 5 minutes. This method can improve the high temperature resistance of the product to a certain extent, but the process time is long. At the same time, because the colloid has initial adhesion, a protective film is also required. This increases the cost and makes it cumbersome for the client to use, which is not conducive to automated production. This solution still cannot solve the problems of wrinkles, delamination, and bubbles when the liquid cooling plate is bent.

[0007] 3) Spraying the insulating coating on the surface of the liquid cooling plate. This solution works better for liquid cooling tubes with smooth surfaces and regular shapes, but for places with bumps and defects on the surface of the liquid cooling plate, the coverage is poor, there is a risk of insulation failure, and rework is required. The overall yield is 60-70%. In addition, an additional process is required in the final use of the client, which is relatively costly.

[0008] Therefore, how to provide an insulating film product that can take into account no initial adhesion, short activation time, excellent aging performance, no bubbles when stamping and bending the liquid cooling plate, delamination, high yield, and easy and rapid automated construction, and effectively apply it to the insulation protection of the liquid cooling plate has become a technical problem that needs to be urgently solved in this field. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a bending-resistant insulating hot-pressed film for a liquid cooling plate and a preparation method thereof in view of the deficiencies in the above-mentioned prior art.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is: an insulating hot pressing film for a liquid cooling plate that is resistant to bending, comprising a first adhesive layer, an insulating base film layer, a second adhesive layer and a hot melt adhesive layer stacked in sequence;

[0011] The raw materials for preparing the hot melt adhesive layer include, by weight: 50 to 100 parts of base resin and 0.2 to 1 part of antioxidant.

[0012] Preferably, the matrix resin is a mixture of one or more of PE, PP, EVA, POE, PVB, and APAO.

[0013] Preferably, the raw materials for preparing the hot melt adhesive layer further include, by weight: 5 to 50 parts of tackifying resin and 5 to 30 parts of functional resin.

[0014] Preferably, the tackifying resin is one or more of rosin resin, terpene resin, petroleum resin, dicyclopentadiene resin, coumarone-indene resin, and styrene series resin.

[0015] Preferably, the functional resin is one or more of EEA, EAA, EBA, EMA, EMMA, EVA-g-MAH, PES, APAO, PA, PU, ​​acrylate, methacrylate, methacrylic acid, acrylamide, glycidyl methacrylate, fumaric acid, itaconic acid, itaconic anhydride and methylmaleic anhydride.

[0016] Preferably, the first adhesive layer and the second adhesive layer are obtained by respectively applying an adhesive solution on the bottom and the surface of the insulating base film layer and then drying them, wherein the adhesive solution comprises an adhesive matrix and deionized water, and the mass concentration of the adhesive matrix in the adhesive solution is 0.1-5%.

[0017] Preferably, the adhesive matrix is ​​one of polyacrylate, polyurethane and polyethyleneimine.

[0018] Preferably, the insulating base film layer is one of PP, PE, PVC, PET, PBT, PEN, PI, PVDF, PVF, and ETFE films.

[0019] Preferably, the thickness of the insulating base film layer is 4-100 μm, the thickness of the first adhesive layer and the second adhesive layer are both 0.1-5 μm, and the thickness of the hot melt adhesive layer is 25-100 μm.

[0020] The present invention also provides a method for preparing the above-mentioned bending-resistant insulating hot-pressed film for liquid cooling plates, comprising the following steps:

[0021] S1, mixing the raw materials for preparing the hot melt adhesive layer uniformly according to a ratio, adding the raw materials to a twin-screw granulator, and extruding and granulating the raw materials to obtain hot melt adhesive particles for forming the hot melt adhesive layer;

[0022] S2, coating the bottom surface of the insulating base film layer with an adhesive solution, controlling the wet adhesive thickness to be 1 to 5 μm, and drying at 75 to 90° C. to form a first adhesive layer;

[0023] S3, coating the surface of the insulating base film layer with an adhesive solution, controlling the wet adhesive thickness to be 1 to 5 μm, and drying at 75 to 90° C. to form a second adhesive layer;

[0024] S4, adding the hot melt adhesive particles prepared in step S1 into a single screw extruder, setting the temperature at 190-220° C., extrusion coating on the surface of the second adhesive layer, and cooling using a patterned cooling roller to form a hot melt adhesive layer, thereby preparing the bending-resistant insulating hot pressing film for the liquid cooling plate.

[0025] The beneficial effects of the present invention are:

[0026] 1) The insulating hot pressing film provided by the present invention forms an adhesive layer by double-sided coating, so that the hot melt adhesive layer and the insulating film are more firmly bonded together, and when overlapping and wrapping the liquid cooling plate, the bonding force between the hot melt adhesive and the insulating film can be improved;

[0027] 2) The hot melt adhesive layer in the present invention is a modified adhesive layer, which can greatly enhance its adhesion with the liquid cooling plate and has excellent high temperature resistance, which can ensure that it still has high adhesion with the liquid cooling plate after aging test; the combination of improved hot melt adhesive adhesion and bending-resistant substrate can resist the extrusion and pulling deformation force caused to the adhesive film when the liquid cooling plate is bent and deformed, thereby avoiding delamination and bubbles.

[0028] 3) In the preparation process of the present invention, the surface of the hot melt adhesive is embossed by a cooling roller during molding, and the surface is non-sticky, so it can be directly rolled up during production without the need for an additional protective film. When customers use the insulating hot pressing film product of the present invention, it is convenient for alignment, there is no need to remove the protective film, the heat activation time is short, and automation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the insulating hot pressing film for the bending-resistant liquid cooling plate of the present invention;

[0030] Figure 2 It is a schematic diagram of the cross section of a liquid cooling tube wrapped with a conventional insulating film;

[0031] Figure 3 Schematic diagram of the wrinkles and bubble defects in the conventional insulation film wrapped on the liquid cooling tube.

[0032] Description of reference numerals:

[0033] 1—first adhesive layer; 2—insulating base film layer; 3—second adhesive layer; 4—hot melt adhesive layer; 7—liquid cooling tube; 8—liquid cooling tube reinforcement rib; 9—insulating film portion overlapping and wrapping the liquid cooling plate. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0035] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0036] The test methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are all commercially available unless otherwise specified. In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0037] Reference Figure 1 The present invention provides a bending-resistant insulating hot-pressing film for a liquid cooling plate, comprising a first adhesive layer 1, an insulating base film layer 2, a second adhesive layer 3 and a hot-melt adhesive layer 4 which are sequentially stacked from bottom to top;

[0038] The raw materials for preparing the hot melt adhesive layer 4 include, by weight: 50-100 parts of base resin, 0.2-1 parts of antioxidant. In some preferred embodiments, the raw materials for preparing the hot melt adhesive layer 4 also include, by weight: 5-50 parts of tackifying resin, 5-30 parts of functional resin.

[0039] In a preferred embodiment, the insulating base film layer 2 is one of PP, PE, PVC, PET, PBT, PEN, PI, PVDF, PVF, and ETFE films. More preferably, it is a PET film that is resistant to bending. The thickness of the insulating base film layer 2 is 4 to 100 μm, and more preferably 18 to 75 μm. The color of the insulating base film layer 2 is transparent, semi-transparent, or colored, and more preferably semi-transparent, white, or black.

[0040] In a preferred embodiment, the base resin is a mixture of one or more of PE, PP, EVA, POE, PVB, and APAO, more preferably EVA or POE. The VA content is 12 to 33%, more preferably 18 to 28%. The melt index of the base resin is 1 to 30, more preferably 2 to 25.

[0041] In a preferred embodiment, the tackifying resin is one or more of rosin resin, terpene resin, petroleum resin, dicyclopentadiene resin (DCPD), coumarone-indene resin, and styrene series resin. The softening point of the tackifying resin is 80-140°C, more preferably 100-120°C.

[0042] In a preferred embodiment, the functional resin is one or more of EEA, EAA, EBA, EMA, EMMA, EVA-g-MAH, PES, APAO, PA, PU, ​​acrylate, methacrylate, methacrylic acid, acrylamide, glycidyl methacrylate, fumaric acid, itaconic acid, itaconic anhydride and methylmaleic anhydride.

[0043] In a preferred embodiment, the antioxidant is a mixture of a hindered phenol antioxidant, a hindered amine primary antioxidant, and a thioester, phosphite compound auxiliary antioxidant, and further a mixture of a hindered amine primary antioxidant 1010 and a phosphite compound auxiliary antioxidant 168, the ratio of which is 2:1.

[0044] In a preferred embodiment, the first adhesive layer 1 and the second adhesive layer 3 are obtained by respectively applying an adhesive solution on the bottom and surface of the insulating base film layer 2 and then drying them. The adhesive solution includes an adhesive matrix and deionized water. The mass concentration of the adhesive matrix in the adhesive solution is 0.1 to 5%, and more preferably 0.1 to 2%.

[0045] In a preferred embodiment, the adhesive matrix is ​​one of polyacrylate, polyurethane, and polyethyleneimine, and more preferably polyethyleneimine.

[0046] In a preferred embodiment, the thickness of the first adhesive layer 1 and the second adhesive layer 3 are both 0.1 to 5 μm, more preferably 0.2 to 2 μm.

[0047] The present invention also provides a method for preparing the above-mentioned bending-resistant insulating hot-pressed film for liquid cooling plates, comprising the following steps:

[0048] S1, mixing the raw materials for preparing the hot melt adhesive layer 4 evenly according to the proportion, adding them to a twin-screw granulator, and extruding and granulating to obtain hot melt adhesive particles for forming the hot melt adhesive layer 4;

[0049] S2, coating the bottom surface of the insulating base film layer 2 with an adhesive solution, controlling the wet adhesive thickness to be 1 to 5 μm, and drying at 75 to 90° C. to form a first adhesive layer 1;

[0050] S3, coating the surface of the insulating base film layer 2 with an adhesive solution, controlling the wet adhesive thickness to be 1 to 5 μm, and drying at 75 to 90° C. to form a second adhesive layer 3;

[0051] S4, adding the hot melt adhesive particles prepared in step S1 into a single screw extruder, setting the temperature at 190-220°C, extrusion coating on the surface of the second adhesive layer 3, and cooling using a patterned cooling roller to form a hot melt adhesive layer 4, thereby preparing a bending-resistant insulating hot pressing film for a liquid cooling plate.

[0052] The thickness of the hot melt adhesive layer 4 is preferably 25-100 μm.

[0053] The equipment for premixing, granulating and coating of hot melt adhesive raw materials can be used separately, or the premixing and granulating can be combined into a loss-in-weight scale twin-screw granulating, or the three functions can be combined into a twin-screw extrusion coating equipment with a loss-in-weight scale.

[0054] The insulating film needs to be coated with adhesive on both sides, which can be done online or purchased from outside with the insulating film already coated with adhesive on both sides.

[0055] The above is the overall concept of the present invention, and detailed embodiments and comparative examples are provided below on the basis of the overall concept of the present invention to further illustrate the present invention.

[0056] The adhesive matrix used in the following examples and comparative examples is EPOMIN (polyethyleneimine) of Nippon Shokubai Co., Ltd., material number SP-1050. This adhesive is a polymer containing amine groups, which can react with hydroxyl groups to form hydrogen bonds and react with carboxyl groups to form ionic bonds. It also has extremely high cationic density, high adhesion and high adsorption. It can be widely used in adhesives, coatings, and adhesives. Water-based adhesives of different concentrations can be prepared by adding water, and the adhesive can be transferred to the insulating film substrate by a scraper or a transfer roller, and then dried in an oven at 75 to 90°C before use. The concentrations of the adhesive solutions used in the first adhesive layer 1 and the second adhesive layer 3 can be the same or different, and the thickness of the formed adhesive layer can be the same or different.

[0057] Example 1

[0058] A method for preparing the above-mentioned bending-resistant insulating hot-pressed film for a liquid cooling plate comprises the following steps:

[0059] S1, mixing the raw materials for preparing the hot melt adhesive layer 4 evenly according to a ratio to obtain hot melt adhesive particles for forming the hot melt adhesive layer 4;

[0060] Among them, in Comparative Example 1 and Examples 1 to 4, only the main resin and the antioxidant are present, and twin-screw granulation is not required. The hot-melt adhesive particles can be obtained by directly mixing them and then proceeding to step S4; wherein the Examples and Comparative Examples require that the prepared raw materials be mixed evenly and then added to a twin-screw granulator, extruded and granulated to obtain hot-melt adhesive particles for forming the hot-melt adhesive layer 4;

[0061] S2, coating the bottom surface of the insulating base film layer 2 with an adhesive solution, controlling the wet adhesive thickness to be 2 μm, and drying at 85° C. for 0.5 s (the equipment is continuously coated, and the line speed is 15 to 60 m / min), to form a first adhesive layer 1;

[0062] S3, coating the adhesive solution on the surface of the insulating base film layer 2, controlling the wet adhesive thickness to be 2 μm, and drying at 85° C. for 0.5 s (the equipment is continuously coated, and the line speed is 15-60 m / min), to form a second adhesive layer 3;

[0063] S4, adding the hot melt adhesive particles prepared in step S1 into a single screw extruder, setting the temperature to 210°C, extruding and coating on the surface of the second adhesive layer 3, and cooling using a patterned cooling roller to form a hot melt adhesive layer 4, thereby preparing a bending-resistant insulating hot pressing film for a liquid cooling plate, and after cooling and shaping, trimming, corona treatment, UV treatment, and winding.

[0064] In this example, the main resin of the hot melt adhesive raw material is LG's E28025, with a VA content of 28% and a melt index of 25 at 190°C.

[0065] The specific raw material ratios and related parameters of each layer in Examples 1-11 and Comparative Examples 1-3 are shown in Table 1 below. The preparation methods of the hot pressing films in each example are the same as that in Example 1.

[0066] Table 1

[0067]

[0068]

[0069] To facilitate understanding and reading, the above table is explained as follows:

[0070] (1) The concentrations in the adhesive layer refer to mass concentrations. The EVA, POE, and APAO in the hot melt adhesive layer 4 are all matrix resins, and the EVA-g-MAH, EMMA, and thermoplastic acrylic resin are all functional resins.

[0071] (2) Additional explanations on some differences in some examples:

[0072] In Example 2, the main resin of the hot melt adhesive raw material is Mitsui's EV406, with a VA content of 20% and a melt index of 20 at 190°C.

[0073] In Example 3, the main resin of the hot melt adhesive raw material is E182L produced by Hanwha Total Petrochemical, with a VA content of 18% and a melt index of 10 at 190°C.

[0074] In Example 4, the main resin of the hot melt adhesive raw material is DOW's ENGAGE, with a melt index of 4.8 at 190°C.

[0075] In Example 5, a tackifying resin Exxon mobil Escorez 5340 is newly added, with a softening point of 139.5° C. and a Tg of 86° C. It should be noted that Examples 6 to 11 are all based on Example 5, and some components or parameters thereof are adjusted.

[0076] In Example 7, Dupunt EVA-g-MAH (ethylene vinyl acetate grafted maleic anhydride) Bynel E418 was added, with a melting index of 11 at 190°C and a melting point of 74°C.

[0077] In Example 8, Mitsui WD 106 is newly added, with a melt index of 0.3 at 190°C, an MA content of 5.8%, and a melting point of 101°C.

[0078] In Comparative Example 2, the main resin of the hot melt adhesive raw material is Vestoplast 888 of Evonik, with a viscosity of 120000±4000 at 190°C and a ring and ball softening point of 161±5°C. The tackifying resin is Cray Valley Wingtack 98, with a softening point of 98±4°C and a Tg of 48°C.

[0079] In Comparative Example 3, Mitsubishi Dianal BR-113 was added, with an acid value (mgKOH / g) of 3.3, a weight average molecular weight of 30,000, and a Tg of 75°C.

[0080] For other unexplained parts, please refer to Table 1 above.

[0081] The performance tests were performed on the hot pressing films prepared in the examples and comparative examples:

[0082] The test conditions are as follows: the peeling force is 90℃ peeling, the shearing sample preparation and test refer to GB / T 7124, and the pull-out test refers to the structural adhesive pull-out test. Among them, the construction process of the insulating film is 160℃ high temperature roller lamination for 30s to make it bond with the test substrate, and then the relevant peeling test is carried out.

[0083] Hygrothermal aging refers to treatment at 65°C and 95% RH for 7 days.

[0084] The test results are shown in Table 2 below:

[0085] Table 2

[0086]

[0087] According to the test results in Table 2, Comparative Examples 1, 2, and 3 all use a single-sided adhesive layer, and all other embodiments use a double-sided adhesive layer. It can be clearly seen that the double-sided adhesive layer has a higher adhesion to the back side of PET.

[0088] Examples 1 to 4 are raw materials of pure EVA, POE or APAO. EVA with different VA contents has different polarities. The higher the VA content, the stronger the adhesion, but there will be certain differences in weather resistance. POE is a thermoplastic elastomer polymerized from ethylene and α-olefin, and APAO is an amorphous α-olefin copolymer. Due to the introduction of α-olefin, both have strong high thermal viscosity and adhesion properties to low surface energy.

[0089] In Comparative Example 2 and Examples 5 and 6, tackifying resin is introduced alone. The addition of tackifying resin can further enhance the adhesion, shearing, pulling, etc. of the adhesive and the PET / aluminum plate.

[0090] In Examples 7 to 8, 11 and Comparative Example 3, polar functional resins having good compatibility with EVA are introduced separately. These functional resins have stronger polarity and can significantly improve the adhesion, shearing, pulling, etc. of the adhesive with PET / aluminum plate.

[0091] In Examples 9 and 10, tackifying resin and functional resin are introduced, and the adhesion and shear strength are significantly enhanced, and the attenuation after aging is very small.

[0092] Embodiments 6 to 8 and embodiments 9 to 11 can be used as preferred solutions.

[0093] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A bending-resistant insulating hot-pressed film for a liquid cooling plate, characterized in that: It includes a first adhesive layer, an insulating base film layer, a second adhesive layer and a hot melt adhesive layer which are stacked in sequence; The raw materials for preparing the hot melt adhesive layer include, by weight: 50 to 100 parts of base resin and 0.2 to 1 part of antioxidant.

2. The insulating hot-pressed film for a liquid cooling plate resistant to bending according to claim 1, characterized in that: The matrix resin is a mixture of one or more of PE, PP, EVA, POE, PVB, and APAO.

3. The bending-resistant insulating hot-pressed film for liquid cooling plate according to claim 1, characterized in that: The raw materials for preparing the hot melt adhesive layer further include, by weight: 5 to 50 parts of tackifying resin and 5 to 30 parts of functional resin.

4. The bending-resistant insulating hot-pressed film for liquid cooling plate according to claim 3, characterized in that: The tackifying resin is one or more of rosin resin, terpene resin, petroleum resin, dicyclopentadiene resin, coumarone-indene resin, and styrene series resin.

5. The bending-resistant insulating hot-pressed film for liquid cooling plate according to claim 3, characterized in that: The functional resin is one or more of EEA, EAA, EBA, EMA, EMMA, EVA-g-MAH, PES, APAO, PA, PU, ​​acrylate, methacrylate, methacrylic acid, acrylamide, glycidyl methacrylate, fumaric acid, itaconic acid, itaconic anhydride and methylmaleic anhydride.

6. The bending-resistant insulating hot-pressed film for liquid cooling plate according to claim 1, characterized in that: The first adhesive layer and the second adhesive layer are obtained by respectively applying adhesive solution on the bottom and the surface of the insulating base film layer and then drying. The adhesive solution includes an adhesive matrix and deionized water. The mass concentration of the adhesive matrix in the adhesive solution is 0.1-5%.

7. The bending-resistant insulating hot-pressed film for liquid cooling plate according to claim 6, characterized in that: The adhesive matrix is ​​one of polyacrylate, polyurethane and polyethyleneimine.

8. The bending-resistant insulating hot-pressed film for liquid cooling plate according to claim 1, characterized in that: The insulating base film layer is one of PP, PE, PVC, PET, PBT, PEN, PI, PVDF, PVF, and ETFE films.

9. The bending-resistant insulating hot-pressed film for liquid cooling plate according to claim 1, characterized in that: The thickness of the insulating base film layer is 4-100 μm, the thickness of the first adhesive layer and the second adhesive layer are both 0.1-5 μm, and the thickness of the hot melt adhesive layer is 25-100 μm.

10. A method for preparing the bending-resistant insulating hot-pressed film for liquid cooling plates according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, mixing the raw materials for preparing the hot melt adhesive layer uniformly according to a ratio, adding the raw materials to a twin-screw granulator, and extruding and granulating the raw materials to obtain hot melt adhesive particles for forming the hot melt adhesive layer; S2, coating the bottom surface of the insulating base film layer with an adhesive solution, controlling the wet adhesive thickness to be 1 to 5 μm, and drying at 75 to 90° C. to form a first adhesive layer; S3, coating the surface of the insulating base film layer with an adhesive solution, controlling the wet adhesive thickness to be 1 to 5 μm, and drying at 75 to 90° C. to form a second adhesive layer; S4, adding the hot melt adhesive particles prepared in step S1 into a single screw extruder, setting the temperature at 190-220° C., extrusion coating on the surface of the second adhesive layer, and cooling using a patterned cooling roller to form a hot melt adhesive layer, thereby preparing the bending-resistant insulating hot pressing film for the liquid cooling plate.

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