High-temperature-resistant hot melt adhesive film with shielding function and preparation method of high-temperature-resistant hot melt adhesive film

Abstract

The invention relates to a high-temperature-resistant hot melt adhesive film with a shielding function and a preparation method thereof, and the high-temperature-resistant hot melt adhesive film with the shielding function comprises a base material layer, an oleophobic and hydrophobic layer, a base material bottom coating and a signal shielding hot melt adhesive layer which is arranged on the base material bottom coating and is opposite to the base material layer, the insulating layer is arranged on the signal shielding hot melt adhesive layer and is opposite to one side of the base material bottom coating; the silicon dioxide tackifying bottom coating is arranged on the insulating layer and is opposite to one side of the signal shielding hot melt adhesive layer; and the low-dielectric hot melt adhesive layer is arranged on the silicon dioxide tackifying bottom coating and is opposite to the insulating layer. According to the high-temperature-resistant hot melt adhesive film, the heat conductivity coefficient and the resistivity of the high-temperature-resistant hot melt adhesive film can be improved, and meanwhile the high-temperature-resistant hot melt adhesive film can have higher insulativity and dielectric property. The invention further provides a preparation method of the high-temperature-resistant hot melt adhesive film with the shielding function.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging, and in particular to a high-temperature resistant hot-melt adhesive film with a shielding function and a preparation method thereof. Background Art

[0002] Hot melt adhesive is made into a film state to meet the needs of bonding. In recent years, it has been increasingly accepted by large industrial production. This is because this adhesive material called hot melt adhesive film has its own unique advantages: (1) easy operation, no cumbersome gluing process, just lay the hot melt adhesive film on the bonding joint; (2) hot melt bonding, it only takes a few seconds or tens of seconds to complete the bonding of a bonding part, which can greatly improve work efficiency; (3) There is no pollution during the production and use of hot melt adhesive film. However, in recent years, the domestic automobile industry has developed rapidly, and new cars have been continuously launched. With the continuous development of the automobile industry, automobile interior materials have been continuously updated, and more and more adhesives are required. The interior design of some models uses polyethylene or polypropylene hard and soft materials. These materials are difficult to bond with adhesives other than hot melt adhesives. Because of this, hot melt adhesive films are widely used in the imported automobile industry.

[0003] There are many types of high temperature resistant hot melt adhesive film products, which have been widely used in automotive interior, automotive wiring, communications and other industries, as well as handbag and decorative box manufacturers. High temperature and high humidity resistance are the development direction of high-end products in these industries. In order to meet the needs of the market, the surface of the high temperature resistant hot melt adhesive film products needs to have hydrophobic and oleophobic functions, and at the same time, it is also necessary to have high peeling force between the connection interfaces and ensure the consistency of surface performance. In addition, the hot melt adhesive film product must have the function of shielding external interference signals to ensure that the signal of the packaged product is not interfered with. At the same time, it is also necessary to ensure that the combination of the new hot melt adhesive film and the surface of wires and cables or metal wires and other workpieces has a high degree of stability, and there is no delamination between the functional layers to ensure long-term high temperature resistance. Summary of the invention

[0004] In view of this, the present invention provides a high temperature resistant hot melt adhesive film with shielding function and a preparation method thereof to meet industrial needs and satisfy the above requirements.

[0005] A high temperature resistant hot melt adhesive film with shielding function, comprising a substrate layer, an oleophobic and hydrophobic layer arranged on one side of the substrate layer, a substrate primer layer arranged on the substrate layer and facing away from the oleophobic and hydrophobic layer, a signal shielding hot melt adhesive layer arranged on the substrate primer layer and facing away from the substrate layer, an insulating layer arranged on the signal shielding hot melt adhesive layer and facing away from the substrate primer layer, a silica adhesion primer layer arranged on the insulating layer and facing away from the signal shielding hot melt adhesive layer, and a low dielectric hot melt adhesive layer arranged on the silica adhesion primer layer and facing away from the insulating layer. The hydrophobic and oleophobic layer is made of titanium dioxide, polyurethane resin and curing agent. The signal shielding adhesive layer is a functional coating layer that has a shielding effect on external interference signals. The insulating layer is made of silica, and the low dielectric hot melt adhesive layer is made of polyurethane solvent-based hot melt adhesive resin.

[0006] Furthermore, the substrate layer is one of PTFE, PET, PA, PI, PC, PS, PE, PP, and EVA.

[0007] Furthermore, the polyurethane resin is replaced by a water-based acrylic resin, and the thickness of the hydrophobic and oleophobic layer is 1 to 20 μm.

[0008] Furthermore, the substrate primer layer and the silica adhesion-enhancing primer layer are both made of polyethyleneimine, ethylene-acrylic acid copolymer, and aqueous polyester solution, and the coating dry weight of the substrate primer layer and the silica adhesion-enhancing primer layer is less than or equal to 0.1 g / m2, and the thickness is less than or equal to 0.05 μm.

[0009] Furthermore, the signal shielding layer is made of polyurethane hot melt adhesive mixed with metallic silver particles of nanometer size.

[0010] Furthermore, the signal shielding layer is composed of a silver foil and an adhesive layer, the silver foil is bonded between the first primer layer and the adhesive layer, and the material of the adhesive layer is the same as that of the first primer layer.

[0011] Furthermore, the insulating layer is formed by a vacuum evaporation machine using a magnetron sputtering process, and the thickness of the insulating layer is 80-200 nm.

[0012] Furthermore, the polyurethane solvent-based hot melt adhesive resin used to prepare the low dielectric hot melt adhesive layer is doped with silver powder, and the content of silver powder is less than or equal to 0.6%.

[0013] A method for preparing a high temperature resistant hot melt adhesive film with a shielding function, comprising the following steps:

[0014] STEP 101: providing the substrate layer;

[0015] STEP 102: coating the hydrophobic and oleophobic layer on one side of the substrate layer, wherein the coating liquid is a mixed liquid prepared in proportion with titanium dioxide, polyurethane resin and curing agent;

[0016] STEP 103: coating a substrate primer layer on the side of the substrate layer facing away from the hydrophobic and oleophobic layer, wherein the substrate primer layer is made of polyethyleneimine, ethylene-acrylic acid copolymer, or aqueous polyester solution;

[0017] STEP 104: Coating the signal shielding adhesive layer on the side of the substrate primer layer facing away from the substrate layer;

[0018] STEP 105: Arranging the insulating layer on the signal shielding adhesive layer, wherein the insulating layer is made of silicon dioxide;

[0019] STEP 106: Coating a silicon dioxide adhesion-promoting primer coating on the side of the insulating layer facing away from the signal shielding adhesive layer;

[0020] STEP 107: Coat the low dielectric hot melt adhesive layer on the side of the silicon dioxide adhesion-promoting primer layer facing away from the insulating layer.

[0021] Furthermore, the polyurethane solvent-based hot melt adhesive resin used to prepare the low dielectric hot melt adhesive layer is doped with silver powder, and the content of silver powder is less than or equal to 0.6%.

[0022] Compared with the prior art, the high temperature resistant hot melt adhesive film with shielding function provided by the present invention is provided with the hydrophobic and oleophobic layer on the substrate layer, and the hydrophobic and oleophobic layer is made of titanium dioxide, polyurethane resin and curing agent, so that the high temperature resistant hot melt adhesive film not only has the effect of hydrophobic and oleophobic, but also can improve the hardness and toughness of the high temperature resistant hot melt adhesive film. The peeling force between the signal shielding adhesive layer and the substrate layer can be increased by the substrate primer layer. The silver powder or silver foil in the signal shielding adhesive layer provides a shielding effect for external electromagnetic signals. In addition, the insulating layer prepared by silicon dioxide can not only improve the thermal conductivity and resistivity of the high temperature hot melt adhesive film, but also make the high temperature hot melt adhesive film have stronger insulation and dielectric properties, and further improve the flame retardant properties of the product. At the same time, the low dielectric hot melt adhesive layer is used, so that it has a high bonding strength to cables and workpieces, no bubbles or pores, and can maintain stability and insulation performance at 125°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic structural diagram of a high temperature resistant hot melt adhesive film with shielding function provided by the present invention. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are further described in detail below. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the protection scope of the present invention.

[0025] like Figure 1 As shown, it is a schematic diagram of the structure of a high-temperature resistant hot melt adhesive film with a shielding function provided by the present invention. The high-temperature resistant hot melt adhesive film with a shielding function includes a substrate layer 10, an oleophobic and hydrophobic layer 20 arranged on one side of the substrate layer 10, a substrate primer layer 30 arranged on the substrate layer 10 and facing away from the oleophobic and hydrophobic layer 20, a signal shielding hot melt adhesive layer 40 arranged on the substrate primer layer 30 and facing away from the substrate layer 10, an insulating layer 50 arranged on the signal shielding hot melt adhesive layer 40 and facing away from the substrate primer layer 30, a silica adhesion primer layer 60 arranged on the insulating layer 50 and facing away from the signal shielding hot melt adhesive layer 40, and a low dielectric hot melt adhesive layer 70 arranged on the silica adhesion primer layer 60 and facing away from the insulating layer 50. It can be imagined that the high-temperature resistant hot melt adhesive film with a shielding function also includes some other functional layers, such as a release layer, a protective film, etc., which are well known to those skilled in the art and will not be described in detail one by one here.

[0026] The substrate layer 10 should be selected from substrates with high strength and high temperature resistance, such as PTFG, LCP, MPI, PET, PA, PI, PC, PS, etc., and soft substrates such as PE, PP, EVA, PP, etc. can also be selected. In this embodiment, the substrate layer 10 is a PET film or a PTFE film, and the PET film can improve the stiffness and tensile strength of the product. Taking advantage of the good stiffness and relatively good tensile strength of PET, it is used as a supporting material for the high-temperature resistant hot melt adhesive film with shielding function of the present invention. The thickness range of the PET film used in the substrate layer 10 is 12 to 25 μm, and a black PET film with a thickness of 20 μm is preferred. The surface of the PET film is used as a coating surface during the solvent-free composite process, and contacts the solvent-free adhesive together with the water-based tackifying resin layer. After the solvent-free composite process, it becomes a coil of a composite film, and after a room temperature aging process, it becomes a composite semi-finished roll film. The usual solvent-free composite process arrangement is to use PET film with high tensile strength as the coating film. PET is a single chemically treated film, and the lower surface has been chemically treated to ensure that the wetting tension required for the necessary composite is ≥52. PTFE film, i.e. polytetrafluoroethylene film, is a polymer that is resistant to high temperature and corrosion. LCP film, i.e. liquid crystal polymer film, and MPI film, i.e. polyimide film, are substrates with excellent temperature resistance.

[0027] The oleophobic and hydrophobic layer 20 is a mixed liquid prepared in proportion by titanium dioxide, polyurethane resin, and curing agent, and the polyurethane resin can also be a water-based acrylic resin. The mixed liquid is coated on the substrate layer 10 by a coating machine. The coating machine itself should be a prior art, and its coating method is not described here. The hydrophobic and oleophobic coating thickness range of the hot melt adhesive film product of this embodiment is 1-8μm, the working concentration of the coating liquid is 25%, and the mesh roller is 100 mesh. After the upper surface of the substrate layer 10 is coated with the hydrophobic and oleophobic coating 20, it is dried with the coating facing outward and then rolled up.

[0028] The substrate primer layer 30 can be made of polyethyleneimine, ethylene-acrylic acid copolymer, or aqueous polyester solution. The substrate primer layer 30 can also be coated on the substrate layer 10 by a coating process in the prior art. The coating dry weight of the substrate primer layer 30 is less than or equal to 0.1 g / m 2 , and the thickness of the substrate primer layer is less than or equal to 0.05 μm. The substrate primer layer 30 and the hydrophobic and oleophobic layer 20 are separated on both sides of the substrate layer 10. The function of the substrate primer layer 30 is to improve the bonding strength between the substrate layer 10 and the signal shielding adhesive layer 40. In this embodiment, the coating process can be completed by a concave coating process characterized by micro-concavities, using an 80-100 mesh screen roller, and the solvent type can be a mixture of water and ethanol.

[0029] The function of the signal shielding adhesive layer 40 is to use a coating process to make a functional coating that has a shielding effect on external interference signals, which is coated on the substrate primer layer 30. The material of the signal shielding adhesive layer 40 can be a polyurethane hot melt adhesive mixed with nano-sized metal silver particles. The nano-sized metal silver (Ag) particles are added to the hot melt adhesive in a certain proportion and mixed evenly to make a coating hot melt adhesive, so that it has the function of shielding electromagnetic signals. The signal shielding adhesive layer 40 has the following several methods, as follows:

[0030] The first preparation method is coating, which uses silver particles mixed with coating liquid to complete the shielding function hot melt adhesive coating:

[0031] The signal shielding adhesive layer 40 having the function of shielding external interference signals is coated on the substrate primer layer 30 of the substrate layer 10, specifically, a coating liquid mixed with polyurethane resin and nano silver particles, and coated on the substrate primer layer 30 by a concave roller. The specific process is to first add nanometer-sized metal silver particles to the polyurethane hot melt adhesive at a ratio of 4-8%, and simultaneously add organic solvents represented by a mixture of butanone and xylene, mix them evenly, seal them and wait for coating. The working concentration of the coating liquid is 25-40%, and the mesh roller is 100-110 meshes. After the coating is completed, it is dried with the coating facing outward and then rolled up.

[0032] The second preparation method is extrusion composite method:

[0033] First, the nano-silver particles are uniformly melted into the PE resin at a ratio of 4-8%, and the melt index MI of the PE resin is 6g / 10min (190°C, 2.16kg). The PE hot melt adhesive pellets with a melting point of 120°C are put into an extruder after drying, and extruded on the substrate primer layer 30 at a melting temperature of 225-260°C with a thickness of 10-50μm. After the action of a cooling roller and an extrusion roller, they are compounded with the substrate layer 10 to form a composite functional substrate for shielding signals.

[0034] The third preparation method is the silver foil dry composite method:

[0035] After the substrate layer 10 is coated with the substrate primer layer 30 , the silver foil is directly compounded on the substrate primer layer 30 , and then a layer of adhesive layer is coated on the silver foil. The material of the adhesive layer can be the same as that of the substrate primer layer 30 .

[0036] The insulating layer 50 can be coated with silicon dioxide on the signal shielding adhesive layer 40 by vacuum coating, and is located on the side of the signal shielding adhesive layer 40 opposite to the substrate primer layer 30. The insulating layer 50 is made of silicon dioxide material. Silicon dioxide has high thermal conductivity and high resistivity for the composite substrate of hot melt adhesive and shielding function, but more importantly, it can make it have stronger insulation and dielectric properties. Therefore, in order to ensure the insulation function of the substrate layer 10 and the signal shielding adhesive layer 40 and the bonding workpieces such as cables, circuit boards, etc., it is preferred to use a transparent silicon dioxide coating completed by a vacuum evaporator using a magnetron sputtering process, with a common thickness range of 80-200nm and a wetting tension ≥38 dyne / cm.

[0037] The purpose of the silica adhesion-enhancing primer layer 60 is to improve the composite strength between the low dielectric hot melt adhesive layer 70 and the insulating coating layer 50 made of the silica, so as to ensure that the low dielectric hot melt adhesive layer 70 does not produce bubble points and the product does not produce peeling cracks when bent. Furthermore, in order to reduce costs and improve production efficiency, the substrate primer layer 60 and the substrate primer layer 30 can use a solution with the same composition, that is, a mixed solution made of polyethyleneimine, ethylene-acrylic acid copolymer, or an aqueous polyester solution. At the same time, in order to prevent the insulating layer 50 made of the silica from cracking due to brittleness, the silica adhesion-enhancing primer layer 60 is twice as thick as the substrate primer layer 30, and the coating dry weight is ≤0.2g / m 2 , thickness is ≤0.1μm.

[0038] The low dielectric hot melt adhesive layer 70 is a polyurethane solvent-type hot melt adhesive resin coated on the silica adhesion primer 60. It can also be made of a water-soluble polyurethane hot melt adhesive resin according to different products, and is compounded with the silica adhesion primer 60 through a solvent-free compounding, a dry compounding process, or an extrusion compounding process. In order to reduce the dielectric constant of the low dielectric hot melt adhesive layer 70, a trace amount of nano silver powder can be added to the polyurethane solvent-type hot melt adhesive resin, and the doping ratio is less than or equal to 0.6%.

[0039] The present invention also provides a method for preparing a high temperature resistant hot melt adhesive film with a shielding function, which comprises the following steps:

[0040] STEP101: Provide the substrate layer 10. The substrate layer 10 can be made of one of the three materials: PTFE, LCP, and MPI. The width of the substrate layer 10 can be 1680 mm, and the wetting tension of the upper and lower surfaces thereof is greater than or equal to 38 dynes / cm. The appearance is flat without ribs, and the end faces are neat.

[0041] STEP102: Coat the hydrophobic and oleophobic layer 20 on one side of the substrate layer 10. Specifically, the substrate layer 10 is placed on the discharge shaft of the coating machine, and the glue tank is placed in a coating liquid with hydrophobic and oleophobic capabilities. The coating liquid can be a mixed liquid prepared in proportion by titanium dioxide, polyurethane resin and curing agent, and the polyurethane resin can be replaced by an aqueous acrylic resin. The coating liquid has the effect of improving the hardness and toughness of the upper surface of the substrate layer 10 and increasing the hydrophobic and oleophobic properties. In this embodiment, 4% nano-grade titanium dioxide is added to the acrylic acid or polyurethane. The coating thickness range of the hydrophobic and oleophobic layer 20 is 0.8 to 25 μm, the working concentration of the coating liquid is 25 to 40%, and a micro-concave mesh roller is preferably used, and the mesh parameter range is 80 to 120 meshes. After the hydrophobic and oleophobic layer 20 is coated on the upper surface of the substrate layer 10, it is dried through a drying tunnel and the hydrophobic and oleophobic layer 20 is rolled up outward.

[0042] STEP 103: Coat a substrate primer layer 30 on the side of the substrate layer 10 facing away from the hydrophobic and oleophobic layer 20. Coat the substrate primer layer 30 on the other side of the substrate layer 10. The substrate primer layer 30 is used to increase the bonding force between the substrate layer 10 and the signal shielding adhesive layer 40. The substrate primer layer 30 is made of polyethyleneimine, ethylene-acrylic acid copolymer, or aqueous polyester solution, and its coating dry weight is less than or equal to 0.1 g / m 2 , thickness is less than or equal to 0.05 μm. During coating, a concave coating process characterized by micro-concaves can be used, and an 80-100 mesh screen roller is used, and the solvent type can be a mixture of water and ethanol.

[0043] STEP 104: Coat the signal shielding adhesive layer 40 on the side of the substrate primer layer 30 facing away from the substrate layer 10. The following methods may be used.

[0044] The first method is a coating method, which is to coat a mixed coating liquid mixed with silver particles on the base primer layer 30 to complete the shielding function hot melt adhesive coating.

[0045] A hot melt adhesive coating having the function of shielding external interference signals is coated on the substrate primer layer 30. The hot melt adhesive coating is a hot melt coating coating made of a coating liquid mixed with polyurethane resin and nano silver particles and coated by a gravure roller.

[0046] The specific process is to add nano-sized metallic silver particles at a ratio of 4-8% to polyurethane hot melt adhesive, and simultaneously add organic solvents represented by a mixture of butanone and xylene, mix them evenly, seal them and wait for coating. During coating, the working concentration can be 25-40%, the mesh roller is 100-110 mesh, and after the coating is completed, it is dried with the coating facing outward and then rolled up.

[0047] Nano-particle silver powder is added to polyurethane hot-melt adhesive resin to produce a coating hot-melt adhesive that has the function of shielding electromagnetic signals, thereby shielding external interference signals.

[0048] The second preparation method is extrusion composite method

[0049] First, a polyurethane hot melt adhesive mixed with nano-sized metallic silver particles at a ratio of 4-8% is extruded in an extruder, that is, a hot melt adhesive film is made by casting a hot melt adhesive resin using an extrusion compounding machine. The nano silver particles are uniformly melted into the polyurethane resin at a ratio of 4-8%. The hot melt adhesive pellets with a melt index MI of 6g / 10min (190°C, 2.16kg) and a melting point of 120°C are put into an extruder after drying and extruded on a substrate primer layer at a melting temperature of 225-260°C with a thickness of 10-50μm. After the action of a cooling roller and an extrusion roller, they are combined with the substrate layer 10 to form a composite function with shielding signals.

[0050] The third preparation method is the silver foil dry composite method

[0051] First, a silver foil is pasted on the substrate primer layer 30, and then a silicon dioxide adhesion layer is coated on the silver foil to form the signal shielding adhesive layer 40. The material of the silicon dioxide adhesion layer can be the same as that of the substrate primer layer 30.

[0052] STEP 105: Disposing the insulating layer 50 on the signal shielding adhesive layer 40;

[0053] The insulating layer 50 is made of silicon dioxide to improve the thermal conductivity and resistivity of the high-temperature hot melt adhesive film, and at the same time, it can also make the high-temperature hot melt adhesive film have stronger insulation and dielectric properties, and further improve the flame retardant performance of the product. Therefore, the insulating layer 50 can ensure the insulation between the high-temperature hot melt adhesive film and the bonding workpiece such as cables, circuit boards, etc. The insulating layer 50 can be coated with silicon dioxide through the magnetron sputtering process of the vacuum coating machine. The coating thickness of the insulating layer 50 is 80 to 2000nm, and the wetting tension is ≥38 dynes / cm.

[0054] STEP106: Coat a silica adhesion primer 60 on the side of the insulating layer 50 facing away from the signal shielding adhesive layer 40. The silica adhesion primer is used to prevent cracks, and its material can be the same as that of the substrate primer 30, that is, made of polyethyleneimine, ethylene-acrylic acid copolymer, or polymer polyester aqueous solution. The silica adhesion primer 60 is completed by micro-concave coating, with a mesh roller parameter of 100-120 mesh and a coating dry weight of 0.03-0.09 g / m 2 , solid content is 0.8% to 5.4, thickness is 0.02 to 0.05 μm. After coating, the coated surface is rolled inward.

[0055] STEP107: Apply the low dielectric hot melt adhesive layer 70 on the side of the silica adhesion promoter primer 60 facing away from the insulating layer 50. Specifically, place the coiled material after vacuum coating on the discharge shaft of the coating machine, and coat it on the silica adhesion promoter primer 60. The adhesive tank is placed in a mixed hot melt adhesive resin solution whose main component is polyurethane, and flame retardants, resin additives, i.e. defoaming additives, curing agents, and antistatic fillers are auxiliary components. After the coating and drying process, the mixed hot melt adhesive resin solution is applied to the insulating layer 50. The working concentration of the coating liquid is 25-40%, and the mesh roller is 80-100 mesh. After the coating is completed, the coating is rolled up with the coating facing outward.

[0056] Compared with the prior art, the high temperature resistant hot melt adhesive film with shielding function provided by the present invention is provided with the hydrophobic and oleophobic layer 20 on the substrate layer 10, and the hydrophobic and oleophobic layer 20 is made of titanium dioxide, polyurethane resin and curing agent, so that the high temperature resistant hot melt adhesive film not only has the effect of hydrophobic and oleophobic, but also can improve the hardness and toughness of the high temperature resistant hot melt adhesive film. The peeling force between the signal shielding adhesive layer 40 and the substrate layer 10 can be increased by the substrate primer layer 30. The silver powder or silver foil in the signal shielding adhesive layer 40 provides a shielding effect for external electromagnetic signals. In addition, the insulating layer 50 prepared by silicon dioxide can not only improve the thermal conductivity and resistivity of the high temperature hot melt adhesive film, but also enable the high temperature hot melt adhesive film to have stronger insulation and dielectric properties, and further improve the flame retardant properties of the product. At the same time, the low dielectric hot melt adhesive layer 70 is used, so that it has a high bonding strength to cables and workpieces, no bubbles or pores, and can maintain stability and insulation properties at 125°C.

[0057] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modification, equivalent substitution or improvement within the spirit of the present invention is included in the scope of the claims of the present invention.

Claims

1. A high temperature resistant hot melt adhesive film with shielding function, characterized in that: The high-temperature resistant hot-melt adhesive film with shielding function includes a substrate layer, an oleophobic and hydrophobic layer arranged on one side of the substrate layer, a substrate primer layer arranged on the substrate layer and facing away from the oleophobic and hydrophobic layer, a signal shielding hot-melt adhesive layer arranged on the substrate primer layer and facing away from the substrate layer, an insulating layer arranged on the signal shielding hot-melt adhesive layer and facing away from the substrate primer layer, a silica adhesion-enhancing primer layer arranged on the insulating layer and facing away from the signal shielding hot-melt adhesive layer, and a low-dielectric hot-melt adhesive layer arranged on the silica adhesion-enhancing primer layer and facing away from the insulating layer, the hydrophobic and oleophobic layer is made of titanium dioxide, polyurethane resin and curing agent, the signal shielding adhesive layer is a functional coating that has a shielding effect on external interference signals, the insulating layer is made of silica, and the low-dielectric hot-melt adhesive layer is made of polyurethane solvent-based hot-melt adhesive resin.

2. The high temperature resistant hot melt adhesive film with shielding function according to claim 1, characterized in that: The substrate layer is one of PTFE, PET, PA, PI, PC, PS, PE, PP, and EVA.

3. The high temperature resistant hot melt adhesive film with shielding function according to claim 1, characterized in that: The polyurethane resin is replaced by a water-based acrylic resin, and the thickness of the hydrophobic and oleophobic layer is 1 to 20 μm.

4. The high temperature resistant hot melt adhesive film with shielding function according to claim 1, characterized in that: The substrate primer and the silica adhesion-enhancing primer are both made of polyethyleneimine, ethylene-acrylic acid copolymer, and aqueous polyester solution, and the coating dry weight of the substrate primer and the silica adhesion-enhancing primer is less than or equal to 0.1 g / m 2 , thickness is less than or equal to 0.05μm.

5. The high temperature resistant hot melt adhesive film with shielding function according to claim 1, characterized in that: The signal shielding layer is made of polyurethane hot melt adhesive mixed with metal silver particles with nanometer particle size.

6. The high temperature resistant hot melt adhesive film with shielding function according to claim 1, characterized in that: The signal shielding layer is composed of a silver foil and an adhesive layer. The silver foil is bonded between the first primer layer and the adhesive layer. The material of the adhesive layer is the same as that of the first primer layer.

7. The high temperature resistant hot melt adhesive film with shielding function according to claim 1, characterized in that: The insulating layer is formed by a vacuum evaporation machine using a magnetron sputtering process, and the thickness of the insulating layer is 80-200 nm.

8. The high temperature resistant hot melt adhesive film with shielding function according to claim 1, characterized in that: The polyurethane solvent-based hot melt adhesive resin used to prepare the low dielectric hot melt adhesive layer is doped with silver powder, and the content of silver powder is less than or equal to 0.6%.

9. The method for preparing a high temperature resistant hot melt adhesive film with shielding function according to any one of claims 1 to 8, comprising the following steps: STEP 101: providing the substrate layer; STEP 102: coating the hydrophobic and oleophobic layer on one side of the substrate layer, wherein the coating liquid is a mixed liquid prepared in proportion with titanium dioxide, polyurethane resin and curing agent; STEP 103: coating a substrate primer layer on the side of the substrate layer facing away from the hydrophobic and oleophobic layer, wherein the substrate primer layer is made of polyethyleneimine, ethylene-acrylic acid copolymer, or aqueous polyester solution; STEP 104: Coating the signal shielding adhesive layer on the side of the substrate primer layer facing away from the substrate layer; STEP 105: Arranging the insulating layer on the signal shielding adhesive layer, wherein the insulating layer is made of silicon dioxide; STEP 106: Coating a silicon dioxide adhesion-promoting primer coating on the side of the insulating layer facing away from the signal shielding adhesive layer; STEP 107: Coat the low dielectric hot melt adhesive layer on the side of the silicon dioxide adhesion-promoting primer layer facing away from the insulating layer.

10. The method for preparing a high temperature resistant hot melt adhesive film with shielding function according to claim 9, characterized in that: The polyurethane solvent-based hot melt adhesive resin used to prepare the low dielectric hot melt adhesive layer is doped with silver powder, and the content of silver powder is less than or equal to 0.6%.

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