A thermal conductive electromagnetic shielding silicone rubber multilayer composite film and its preparation method and application

Abstract

The present invention discloses a thermally conductive electromagnetic shielding silicone rubber multilayer composite film, and its preparation method and application. The thermally conductive electromagnetic shielding silicone rubber multilayer composite film of the present invention comprises a nickel-plated glass fiber cloth, a magnetic shielding layer, a conductive shielding layer and a thermal conductive layer stacked in sequence, the magnetic shielding layer is a silicone rubber layer containing a magnetic filler, the conductive shielding layer is a silicone rubber layer containing a conductive filler, and the thermal conductive layer is a silicone rubber layer containing a thermal conductive filler. The preparation method of the thermally conductive electromagnetic shielding silicone rubber multilayer composite film of the present invention is very simple, and the magnetic shielding layer, the conductive shielding layer and the thermal conductive layer are prepared in sequence on one side of the nickel-plated glass fiber cloth. The thermally conductive electromagnetic shielding silicone rubber multilayer composite film of the present invention has the advantages of excellent thermal conductivity, excellent electromagnetic shielding performance, high mechanical strength, good flexibility, small thickness, etc., and its preparation process is simple. It has broad application prospects in the fields of 5G communications, consumer electronics, power batteries, national defense and military industry, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone rubber composite materials, and in particular to a heat-conducting electromagnetic shielding silicone rubber multilayer composite film, a preparation method thereof, and applications thereof. Background Art

[0002] With the rapid development of electronic communications technology, the operating frequencies of various electronic components and communications equipment have gradually increased, generating more heat and significantly raising the temperature of electronic components. This has led to a decrease in the operating stability of these components and equipment, and even shortened their service life. Furthermore, electromagnetic radiation in various frequency bands in the environment not only affects the normal operation of communications equipment but also poses potential risks to human health.

[0003] Therefore, it is of great significance to develop a silicone rubber composite material with both excellent thermal conductivity and excellent electromagnetic shielding performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a heat-conducting electromagnetic shielding silicone rubber multilayer composite film and a preparation method and application thereof.

[0005] The technical solution adopted by the present invention is:

[0006] A thermally conductive electromagnetic shielding silicone rubber multilayer composite film comprises a nickel-plated glass fiber cloth, a magnetic shielding layer, a conductive shielding layer and a thermally conductive layer stacked in sequence; the magnetic shielding layer is a silicone rubber layer containing magnetic fillers; the conductive shielding layer is a silicone rubber layer containing conductive fillers; and the thermally conductive layer is a silicone rubber layer containing thermally conductive fillers.

[0007] Preferably, the nickel content of the nickel-plated glass fiber cloth is 5wt% to 30wt%.

[0008] Preferably, the nickel-plated glass fiber cloth is prepared by the following method: degreasing the glass fiber cloth, sensitizing it with an acidic stannous chloride solution, activating it with an acidic palladium chloride solution, and then performing chemical nickel plating to obtain the nickel-plated glass fiber cloth.

[0009] Preferably, the specific operation of degreasing is: immersing the glass fiber cloth in acetone for soaking treatment.

[0010] Preferably, the mass ratio of the glass fiber cloth to acetone is 1:20-200.

[0011] Preferably, the acidic stannous chloride solution is prepared by mixing stannous chloride, concentrated hydrochloric acid and water in a mass ratio of 0.05-0.25:5-10:100.

[0012] Preferably, the mass ratio of the glass fiber cloth to the acidic stannous chloride solution is 1:20-200.

[0013] Preferably, the acidic palladium chloride solution is prepared by mixing palladium chloride, concentrated hydrochloric acid and water in a mass ratio of 0.01-0.05:0.5-1:100.

[0014] Preferably, the mass ratio of the glass fiber cloth to the acidic palladium chloride solution is 1:50-300.

[0015] Preferably, the pH value of the chemical plating solution used for the chemical nickel plating is 4-6, the total concentration of the solute is 5g / L-50g / L, and the solute is composed of nickel salt, sodium citrate and sodium hypophosphite in a mass ratio of 1:1-2:1-3.

[0016] Preferably, the nickel salt is at least one of nickel nitrate, nickel chloride and nickel sulfate.

[0017] Preferably, the mass ratio of the glass fiber cloth to the chemical plating solution is 1:100-500.

[0018] Preferably, the chemical nickel plating is carried out at a temperature of 60° C. to 100° C., and the time for the chemical nickel plating is 20 min to 90 min.

[0019] Preferably, the thickness of the nickel-plated glass fiber cloth is 0.03 mm to 0.10 mm.

[0020] Preferably, the magnetic filler is at least one of ferroferric oxide powder, zinc-manganese ferrite powder, and cobalt ferrite powder.

[0021] Preferably, the particle size of the magnetic filler is 10 nm to 200 nm.

[0022] Preferably, the particle size of the ferrosoferric oxide powder is 10 nm to 100 nm.

[0023] Preferably, the particle size of the zinc-manganese ferrite powder is 30 nm to 200 nm.

[0024] Preferably, the particle size of the cobalt ferrite powder is 20 nm to 150 nm.

[0025] Preferably, the thickness of the magnetic shielding layer is 0.1 mm to 1.0 mm.

[0026] Preferably, the conductive filler is at least one of carbon nanotubes, graphene nanosheets, fullerenes, and MXene nanosheets.

[0027] Preferably, the carbon nanotubes have a length of 3 μm to 20 μm and a diameter of 10 nm to 30 nm.

[0028] Preferably, the thickness of the graphene nanosheets is 0.8 nm to 5 nm.

[0029] Preferably, the particle size of the fullerene is 0.8 nm to 5 nm.

[0030] Preferably, the thickness of the MXene nanosheet is 0.8 nm to 5 nm.

[0031] Preferably, the thickness of the conductive shielding layer is 0.1 mm to 1.0 mm.

[0032] Preferably, the thermally conductive filler is at least one of hexagonal boron nitride, aluminum oxide powder, and aluminum nitride powder.

[0033] Preferably, the particle size of the thermally conductive filler is 1 μm to 100 μm.

[0034] Preferably, the diameter of the hexagonal boron nitride is 2 μm to 30 μm.

[0035] Preferably, the particle size of the aluminum oxide powder is 20 μm to 90 μm.

[0036] Preferably, the particle size of the aluminum nitride powder is 30 μm to 80 μm.

[0037] Preferably, the thickness of the heat-conducting layer is 0.1 mm to 1.0 mm.

[0038] Preferably, the thermally conductive electromagnetic shielding silicone rubber multilayer composite film comprises the following raw materials in parts by mass:

[0039] Vinyl silicone oil: 80 to 100 parts;

[0040] Hydrogenated silicone oil: 1 to 5 parts;

[0041] Platinum catalyst: 0.1 to 0.5 parts;

[0042] Inhibitor: 0.001 to 0.02 parts;

[0043] Magnetic filler: 5 to 60 parts;

[0044] Conductive filler: 2 to 12 parts;

[0045] Thermal conductive filler: 30 to 100 parts;

[0046] Nickel-plated glass fiber cloth: 0.01 to 1 part.

[0047] Preferably, the viscosity of the vinyl silicone oil is 50 mPa·s to 2000 mPa·s.

[0048] Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.1 wt% to 1.0 wt%.

[0049] Preferably, the platinum catalyst is at least one of a methylvinylsiloxane-platinum complex, an isopropanol solution of chloroplatinic acid, a platinum-tetrahydrofuran complex, and a vinylpolysiloxane-platinum complex.

[0050] Preferably, the inhibitor is at least one of ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, and 3,6-dimethyl-1-heptyn-3-ol.

[0051] A method for preparing the thermally conductive electromagnetic shielding silicone rubber multilayer composite film as described above comprises the following steps:

[0052] 1) vinyl silicone oil, hydrogenated silicone oil, magnetic filler, platinum catalyst and inhibitor are mixed, coated on one side of nickel-plated glass fiber cloth, and then vulcanized to obtain a double-layer composite film containing a magnetic shielding layer and nickel-plated glass fiber cloth;

[0053] 2) mixing vinyl silicone oil, hydrogenated silicone oil, conductive filler, platinum catalyst and inhibitor, coating the mixture on the surface of the magnetic shielding layer, and vulcanizing the mixture to obtain a three-layer composite film comprising a conductive shielding layer, a magnetic shielding layer and nickel-plated glass fiber cloth;

[0054] 3) Vinyl silicone oil, hydrogenated silicone oil, thermal conductive filler, platinum catalyst and inhibitor are mixed and coated on the surface of the conductive shielding layer, and then vulcanized to obtain a four-layer composite film comprising a thermal conductive layer, a conductive shielding layer, a magnetic shielding layer and nickel-plated glass fiber cloth, i.e., a thermal conductive electromagnetic shielding silicone rubber multilayer composite film.

[0055] Preferably, the vulcanization in step 1) is carried out at a temperature of 100° C. to 180° C., and the vulcanization time is 10 min to 60 min.

[0056] Preferably, the vulcanization in step 2) is carried out at a temperature of 100° C. to 180° C., and the vulcanization time is 10 min to 60 min.

[0057] Preferably, the vulcanization in step 3) is carried out at a temperature of 100° C. to 180° C., and the vulcanization time is 10 min to 60 min.

[0058] An electronic device comprises the above-mentioned heat-conductive electromagnetic shielding silicone rubber multilayer composite film.

[0059] The beneficial effects of the present invention are: the thermally conductive electromagnetic shielding silicone rubber multilayer composite film of the present invention has the advantages of excellent thermal conductivity, excellent electromagnetic shielding performance, high mechanical strength, good flexibility, and small thickness, and its preparation process is simple. It has broad application prospects in 5G communications, consumer electronics, power batteries, national defense and military industries and other fields.

[0060] Specifically:

[0061] 1) The thermally conductive electromagnetic shielding silicone rubber multilayer composite film of the present invention adopts a multilayer structural design, and different layers can respectively realize conductive shielding, magnetic shielding and in-plane thermal conductivity functions. Moreover, the electromagnetic shielding effectiveness and thermal conductivity of the composite film can be adjusted over a wide range by changing the composition and dosage of the functional fillers, and the applicability is strong;

[0062] 2) The thermal conductive electromagnetic shielding silicone rubber multilayer composite film of the present invention has excellent thermal conductivity (the in-plane thermal conductivity can reach up to 4.2W·m -1 ·k -1 ), excellent electromagnetic shielding performance (electromagnetic shielding effectiveness EMI SE can reach up to 60dB), high mechanical strength, good flexibility, and stable electromagnetic shielding effectiveness (EMI SE can still reach 59dB after 180° repeated bending 1500 times);

[0063] 3) The thermally conductive and electromagnetically shielding silicone rubber multilayer composite film of the present invention has a typical Janus structure (one side has insulating thermal conductivity, and the other side has electrical conductivity and electromagnetic shielding properties). BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a schematic structural diagram of the heat-conducting electromagnetic shielding silicone rubber multilayer composite film of the present invention.

[0065] Description of the accompanying drawings: 10, nickel-plated glass fiber cloth; 20, magnetic shielding layer; 30, conductive shielding layer; 40, thermal conductive layer.

[0066] Figure 2 Graph showing the electromagnetic shielding effectiveness test results of the thermally conductive electromagnetic shielding silicone rubber multilayer composite films of Examples 1 to 5 and the silicone rubber multilayer composite films of Comparative Examples 1 to 2.

[0067] Figure 3 Graph showing the thermal conductivity test results of the heat-conductive electromagnetic shielding silicone rubber multilayer composite films of Examples 1 to 5 and the silicone rubber multilayer composite films of Comparative Examples 1 to 2.

[0068] Figure 4 This is a graph showing the electromagnetic shielding effectiveness test results of the thermally conductive electromagnetic shielding silicone rubber multilayer composite film of Example 5 before and after being bent 180° 1500 times. DETAILED DESCRIPTION

[0069] The present invention will be further explained and illustrated below with reference to specific embodiments.

[0070] Example 1:

[0071] A heat-conducting electromagnetic shielding silicone rubber multilayer composite film (structural schematic diagram as shown Figure 1As shown), it consists of a nickel-plated glass fiber cloth 10, a magnetic shielding layer 20, a conductive shielding layer 30 and a thermal conductive layer 40 stacked in sequence; the magnetic shielding layer 20 is a silicone rubber layer containing magnetic fillers; the conductive shielding layer 30 is a silicone rubber layer containing conductive fillers; and the thermal conductive layer 40 is a silicone rubber layer containing thermal conductive fillers.

[0072] The raw material composition of the above-mentioned thermal conductive electromagnetic shielding silicone rubber multilayer composite film is shown in the following table:

[0073] Table 1 Raw material composition of thermal conductive electromagnetic shielding silicone rubber multilayer composite film

[0074]

[0075]

[0076] Note:

[0077] Nickel-plated fiberglass cloth is made by the following method:

[0078] 1) Mix stannous chloride, concentrated hydrochloric acid (36% by mass), and deionized water in a mass ratio of 0.05:7.5:100, and ultrasonically disperse for 5 minutes to obtain an acidic stannous chloride solution;

[0079] 2) palladium chloride, concentrated hydrochloric acid (36% by mass), and deionized water were mixed in a mass ratio of 0.01:0.5:100, and ultrasonically dispersed for 5 minutes to obtain an acidic palladium chloride solution;

[0080] 3) dilute hydrochloric acid (pH = 5), nickel chloride, sodium citrate, and sodium hypophosphite were mixed in a mass ratio of 100:3:3:4, and stirred at a stirrer speed of 400 rpm for 5 minutes to obtain a chemical plating solution;

[0081] 4) Place the glass fiber cloth in acetone with a mass ratio of 1:100, soak at room temperature for 30 minutes, then wash with deionized water for 3 times, then place in a blast drying oven at 80°C for 10 minutes, then place the glass fiber cloth in an acidic stannous chloride solution with a mass ratio of 1:150, soak at room temperature for 10 minutes, then wash with deionized water for 3 times, then place in a blast drying oven at 80°C for 10 minutes, then place the glass fiber cloth in an acidic stannous chloride solution. The glass fiber cloth was placed in an acidic palladium chloride solution with a mass ratio of 1:150 to the acidic palladium chloride solution, soaked at room temperature for 10 minutes, washed three times with deionized water, and then dried in a blast drying oven at 80°C for 10 minutes. The glass fiber cloth was then placed in a chemical plating solution with a mass ratio of 1:300 to the chemical plating solution, and then chemical nickel plating was performed at 80°C for 40 minutes. The glass fiber cloth was then washed three times with anhydrous ethanol and then dried in a blast drying oven at 80°C for 10 minutes to obtain nickel-plated glass fiber cloth.

[0082] The preparation method of the above-mentioned thermal conductive electromagnetic shielding silicone rubber multilayer composite film comprises the following steps:

[0083] 1) Vinyl silicone oil, hydrogenated silicone oil, ferrosoferric oxide powder, methylvinylsiloxane-platinum complex, and ethynylcyclohexanol were added to a homogenizer and mixed for 60 seconds at a homogenizer speed of 1200 rpm. The mixture was then coated on one side of a nickel-plated glass fiber cloth and vulcanized in a flat-plate vulcanizer at 120° C. for 20 minutes to obtain a double-layer composite film comprising a magnetic shielding layer (0.3 mm thick) and nickel-plated glass fiber cloth.

[0084] 2) adding vinyl silicone oil, hydrogenated silicone oil, carbon nanotubes, methylvinylsiloxane-platinum complex, and ethynylcyclohexanol into a homogenizer and mixing them for 80 seconds at a homogenizer speed of 1500 rpm, coating the mixture on the surface of the magnetic shielding layer, and vulcanizing the mixture in a flat-plate vulcanizer at 120° C. for 20 minutes to obtain a three-layer composite film comprising a conductive shielding layer (0.3 mm thick), a magnetic shielding layer, and a nickel-plated glass fiber cloth;

[0085] 3) Vinyl silicone oil, hydrogenated silicone oil, hexagonal boron nitride, methylvinylsiloxane-platinum complex and ethynylcyclohexanol were added to a homogenizer, mixed for 40 seconds at a homogenizer speed of 1200 rpm, coated on the surface of the conductive shielding layer, and then vulcanized in a flat vulcanizer at 140° C. for 10 minutes to obtain a four-layer composite film comprising a thermal conductive layer (thickness 0.3 mm), a conductive shielding layer, a magnetic shielding layer and a nickel-plated glass fiber cloth, i.e., a thermal conductive electromagnetic shielding silicone rubber multilayer composite film.

[0086] Example 2:

[0087] A heat-conducting electromagnetic shielding silicone rubber multilayer composite film (with the same structure as in Example 1), the raw material composition of which is shown in the following table:

[0088] Table 2 Raw material composition of thermal conductive electromagnetic shielding silicone rubber multilayer composite film

[0089]

[0090] The preparation method of the above-mentioned thermal conductive electromagnetic shielding silicone rubber multilayer composite film comprises the following steps:

[0091] 1) Vinyl silicone oil, hydrogen silicone oil, ferrosoferric oxide powder, methylvinylsiloxane-platinum complex and 3,5-dimethyl-1-hexyn-3-ol were added to a homogenizer and mixed for 60 seconds at a homogenizer speed of 1200 rpm, and then coated on one side of nickel-plated glass fiber cloth (same as in Example 1), and then placed in a flat vulcanizer at 120° C. for 20 minutes to obtain a double-layer composite film containing a magnetic shielding layer (thickness 0.5 mm) and nickel-plated glass fiber cloth;

[0092] 2) adding vinyl silicone oil, hydrogenated silicone oil, carbon nanotubes, methylvinylsiloxane-platinum complex, and 3,5-dimethyl-1-hexyn-3-ol into a homogenizer, mixing them for 60 seconds at a homogenizer speed of 2000 rpm, coating them on the surface of the magnetic shielding layer, and then vulcanizing them in a flat-plate vulcanizer at 130° C. for 15 minutes to obtain a three-layer composite film comprising a conductive shielding layer (thickness 0.5 mm), a magnetic shielding layer, and a nickel-plated glass fiber cloth;

[0093] 3) Vinyl silicone oil, hydrogenated silicone oil, hexagonal boron nitride, methylvinylsiloxane-platinum complex and 3,5-dimethyl-1-hexyn-3-ol were added to a homogenizer, mixed for 40 seconds at a homogenizer speed of 1200 rpm, coated on the surface of the conductive shielding layer, and then placed in a flat vulcanizer for vulcanization at 140° C. for 10 minutes to obtain a four-layer composite film comprising a thermal conductive layer (thickness 0.3 mm), a conductive shielding layer, a magnetic shielding layer and a nickel-plated glass fiber cloth, i.e., a thermal conductive electromagnetic shielding silicone rubber multilayer composite film.

[0094] Example 3:

[0095] A heat-conducting electromagnetic shielding silicone rubber multilayer composite film (with the same structure as in Example 1), the raw material composition of which is shown in the following table:

[0096] Table 3 Raw material composition of thermal conductive electromagnetic shielding silicone rubber multilayer composite film

[0097]

[0098] Note: The nickel-plated glass fiber cloth in this embodiment is prepared in the same manner as in Example 1 except that the chemical nickel plating time is adjusted from 40 min to 60 min.

[0099] The preparation method of the above-mentioned thermal conductive electromagnetic shielding silicone rubber multilayer composite film comprises the following steps:

[0100] 1) Vinyl silicone oil, hydrogenated silicone oil, ferrosoferric oxide powder, methylvinylsiloxane-platinum complex, and ethynylcyclohexanol were added to a homogenizer and mixed for 60 seconds at a homogenizer speed of 1200 rpm. The mixture was then coated on one side of a nickel-plated glass fiber cloth and vulcanized in a flat-plate vulcanizer at 120° C. for 20 minutes to obtain a double-layer composite film comprising a magnetic shielding layer (0.5 mm thick) and nickel-plated glass fiber cloth.

[0101] 2) adding vinyl silicone oil, hydrogenated silicone oil, carbon nanotubes, methylvinylsiloxane-platinum complex, and ethynylcyclohexanol into a homogenizer and mixing them for 80 seconds at a homogenizer speed of 1500 rpm, coating the mixture on the surface of the magnetic shielding layer, and vulcanizing the mixture in a flat-plate vulcanizer at 120° C. for 20 minutes to obtain a three-layer composite film comprising a conductive shielding layer (0.5 mm thick), a magnetic shielding layer, and a nickel-plated glass fiber cloth;

[0102] 3) Vinyl silicone oil, hydrogenated silicone oil, hexagonal boron nitride, methylvinylsiloxane-platinum complex and ethynylcyclohexanol were added to a homogenizer, mixed for 30 seconds at a homogenizer speed of 1300 rpm, coated on the surface of the conductive shielding layer, and then vulcanized in a flat vulcanizer at 120° C. for 15 minutes to obtain a four-layer composite film comprising a thermal conductive layer (thickness 0.3 mm), a conductive shielding layer, a magnetic shielding layer and a nickel-plated glass fiber cloth, i.e., a thermal conductive electromagnetic shielding silicone rubber multilayer composite film.

[0103] Example 4:

[0104] A heat-conducting electromagnetic shielding silicone rubber multilayer composite film (with the same structure as in Example 1), the raw material composition of which is shown in the following table:

[0105] Table 4 Raw material composition of thermal conductive electromagnetic shielding silicone rubber multilayer composite film

[0106]

[0107] The preparation method of the above-mentioned thermal conductive electromagnetic shielding silicone rubber multilayer composite film comprises the following steps:

[0108] 1) Vinyl silicone oil, hydrogen silicone oil, ferrosoferric oxide powder, platinum-tetrahydrofuran complex, and 3,5-dimethyl-1-hexyn-3-ol were added to a homogenizer and mixed for 40 seconds at a homogenizer speed of 2000 rpm. The mixture was then coated on one side of a nickel-plated glass fiber cloth (same as in Example 3), and then vulcanized in a flat vulcanizer at 140° C. for 15 minutes to obtain a double-layer composite film comprising a magnetic shielding layer (0.5 mm thick) and a nickel-plated glass fiber cloth;

[0109] 2) adding vinyl silicone oil, hydrogenated silicone oil, carbon nanotubes, platinum-tetrahydrofuran complex, and 3,5-dimethyl-1-hexyn-3-ol into a homogenizer, mixing them for 80 seconds at a homogenizer speed of 1500 rpm, coating them on the surface of the magnetic shielding layer, and then vulcanizing them in a flat-plate vulcanizer at 120° C. for 20 minutes to obtain a three-layer composite film comprising a conductive shielding layer (thickness 0.7 mm), a magnetic shielding layer, and a nickel-plated glass fiber cloth;

[0110] 3) Vinyl silicone oil, hydrogen-containing silicone oil, hexagonal boron nitride, platinum-tetrahydrofuran complex and 3,5-dimethyl-1-hexyn-3-ol were added to a homogenizer, mixed for 40 seconds at a homogenizer speed of 1200 rpm, coated on the surface of the conductive shielding layer, and then placed in a flat vulcanizer for vulcanization at 140° C. for 10 minutes to obtain a four-layer composite film comprising a thermal conductive layer (thickness 0.3 mm), a conductive shielding layer, a magnetic shielding layer and a nickel-plated glass fiber cloth, i.e., a thermal conductive electromagnetic shielding silicone rubber multilayer composite film.

[0111] Example 5:

[0112] A heat-conducting electromagnetic shielding silicone rubber multilayer composite film (with the same structure as in Example 1), the raw material composition of which is shown in the following table:

[0113] Table 5 Raw material composition of thermal conductive electromagnetic shielding silicone rubber multilayer composite film

[0114]

[0115] The preparation method of the above-mentioned thermal conductive electromagnetic shielding silicone rubber multilayer composite film comprises the following steps:

[0116] 1) Vinyl silicone oil, hydrogen silicone oil, ferrosilicate powder, an isopropyl alcohol solution of chloroplatinic acid, and ethynylcyclohexanol were added to a homogenizer and mixed for 60 seconds at a homogenizer speed of 1200 rpm. The mixture was then coated on one side of nickel-plated glass fiber cloth (same as in Example 3) and vulcanized in a flat-plate vulcanizer at 120° C. for 20 minutes to obtain a double-layer composite film comprising a magnetic shielding layer (0.7 mm thick) and nickel-plated glass fiber cloth;

[0117] 2) Vinyl silicone oil, hydrogenated silicone oil, carbon nanotubes, an isopropyl alcohol solution of chloroplatinic acid, and ethynylcyclohexanol were added to a homogenizer and mixed at a homogenizer speed of 1500 rpm for 80 seconds. The mixture was then coated on the surface of the magnetic shielding layer and vulcanized in a flat-plate vulcanizer at 120° C. for 20 minutes to obtain a three-layer composite film comprising a conductive shielding layer (0.7 mm thick), a magnetic shielding layer, and a nickel-plated glass fiber cloth.

[0118] 3) Vinyl silicone oil, hydrogenated silicone oil, hexagonal boron nitride, an isopropyl alcohol solution of chloroplatinic acid, and ethynylcyclohexanol were added to a homogenizer, mixed for 30 seconds at a homogenizer speed of 1500 rpm, coated on the surface of the conductive shielding layer, and then vulcanized in a flat-plate vulcanizer at 120° C. for 15 minutes to obtain a four-layer composite film comprising a thermal conductive layer (thickness 0.3 mm), a conductive shielding layer, a magnetic shielding layer, and a nickel-plated glass fiber cloth, i.e., a thermal conductive electromagnetic shielding silicone rubber multilayer composite film.

[0119] Comparative Example 1:

[0120] A silicone rubber multilayer composite film consists of a nickel-plated glass fiber cloth, a conductive shielding layer and a heat-conducting layer stacked in sequence; the conductive shielding layer is a silicone rubber layer containing conductive fillers; and the heat-conducting layer is a silicone rubber layer containing heat-conducting fillers.

[0121] The raw material composition of the above-mentioned silicone rubber multilayer composite film is shown in the following table:

[0122] Table 6 Raw material composition of silicone rubber multilayer composite film

[0123]

[0124] The method for preparing the above-mentioned silicone rubber multilayer composite film comprises the following steps:

[0125] 1) Vinyl silicone oil, hydrogenated silicone oil, carbon nanotubes, methylvinylsiloxane-platinum complex, and ethynylcyclohexanol were added to a homogenizer and mixed for 80 seconds at a homogenizer speed of 1500 rpm. The mixture was then coated on one side of nickel-plated glass fiber cloth (same as in Example 1), and then vulcanized in a flat-plate vulcanizer at 120° C. for 20 minutes to obtain a double-layer composite film comprising a conductive shielding layer (0.3 mm thick) and nickel-plated glass fiber cloth;

[0126] 2) Vinyl silicone oil, hydrogenated silicone oil, hexagonal boron nitride, methylvinylsiloxane-platinum complex, and ethynylcyclohexanol were added to a homogenizer and mixed for 40 seconds at a homogenizer speed of 1200 rpm. The mixture was then coated on the surface of the conductive shielding layer and vulcanized in a flat vulcanizer at 140° C. for 10 minutes to obtain a three-layer composite film comprising a thermal conductive layer (thickness 0.3 mm), a conductive shielding layer, and a nickel-plated glass fiber cloth, i.e., a silicone rubber multilayer composite film.

[0127] Comparative Example 2:

[0128] A silicone rubber multilayer composite film consists of a nickel-plated glass fiber cloth, a magnetic shielding layer and a heat-conducting layer stacked in sequence; the magnetic shielding layer is a silicone rubber layer containing magnetic fillers; and the heat-conducting layer is a silicone rubber layer containing heat-conducting fillers.

[0129] The raw material composition of the above-mentioned silicone rubber multilayer composite film is shown in the following table:

[0130] Table 7 Raw material composition of silicone rubber multilayer composite film

[0131]

[0132] The method for preparing the above-mentioned silicone rubber multilayer composite film comprises the following steps:

[0133] 1) Vinyl silicone oil, hydrogen silicone oil, ferrosilicate powder, an isopropyl alcohol solution of chloroplatinic acid, and 3,6-dimethyl-1-heptyn-3-ol were added to a homogenizer and mixed for 80 seconds at a homogenizer speed of 1500 rpm. The mixture was then coated on one side of a nickel-plated glass fiber cloth (same as in Example 1), and then vulcanized in a flat vulcanizer at 120° C. for 20 minutes to obtain a double-layer composite film comprising a magnetic shielding layer (0.3 mm thick) and a nickel-plated glass fiber cloth;

[0134] 2) Vinyl silicone oil, hydrogenated silicone oil, hexagonal boron nitride, an isopropanol solution of chloroplatinic acid, and 3,6-dimethyl-1-heptyn-3-ol were added to a homogenizer, mixed for 30 seconds at a homogenizer speed of 1500 rpm, coated on the surface of the conductive shielding layer, and then placed in a flat vulcanizer for vulcanization at 120° C. for 15 minutes to obtain a three-layer composite film comprising a thermal conductive layer (thickness 0.3 mm), a magnetic shielding layer, and a nickel-plated glass fiber cloth, i.e., a silicone rubber multilayer composite film.

[0135] Performance testing:

[0136] The electromagnetic shielding effectiveness test results of the thermal conductive electromagnetic shielding silicone rubber multilayer composite films of Examples 1 to 5 and the silicone rubber multilayer composite films of Comparative Examples 1 to 2 are shown in the figure. Figure 2 As shown in the figure, the thermal conductivity test results of the thermal conductive electromagnetic shielding silicone rubber multilayer composite films of Examples 1 to 5 and the silicone rubber multilayer composite films of Comparative Examples 1 to 2 are as follows Figure 3 As shown in FIG. 1 , the electromagnetic shielding effectiveness test results of the thermal conductive electromagnetic shielding silicone rubber multilayer composite film of Example 5 before and after being bent 180° 1500 times are shown in FIG. Figure 4 As shown, the test results of thermal conductivity, electromagnetic shielding performance and tensile strength of the thermal conductive electromagnetic shielding silicone rubber multilayer composite films of Examples 1 to 5 and the silicone rubber multilayer composite films of Comparative Examples 1 to 2 are shown in the following table:

[0137] Table 8 Thermal conductivity, electromagnetic shielding performance and tensile strength test results

[0138]

[0139] Note:

[0140] Thermal conductivity: Tested with reference to GB / T 32064-2015 "Test method for thermal conductivity and thermal diffusivity of building materials using transient plane heat sources" using a TPS 2500S thermal constant analyzer from Swedish Hotdisk. During the test, the probe was placed between the sample to ensure a close fit between the sample and the probe. Each sample was tested three times, and the average value was taken.

[0141] EMI SE (Electromagnetic Shielding Performance): A Rohde & Schwarz ZNB-20 vector network analyzer was used to test the electromagnetic parameters of the sample under test using the waveguide method, and then the electromagnetic shielding effectiveness of the sample under test was calculated. The test frequency range was 8.2 GHz to 12.4 GHz.

[0142] Tensile strength: refer to "GB / T 528-2009 Vulcanized rubber or thermoplastic rubber - Determination of tensile stress-strain properties" using a universal material testing machine for testing at a tensile rate of 200 mm / min.

[0143] Depend on Figures 2-4 From Table 8, we can see that:

[0144] a) The thermally conductive electromagnetic shielding silicone rubber multilayer composite films of Examples 1 to 5 are all composed of nickel-plated glass fiber cloth, a ferroferric oxide magnetic shielding layer, a carbon nanotube conductive shielding layer, and a boron nitride thermal conductive layer, and have excellent thermal conductivity and electromagnetic shielding performance;

[0145] b) Comparative Example 1 lacks the ferroferric oxide magnetic shielding layer compared to Examples 1-5, while Comparative Example 2 lacks the carbon nanotube conductive shielding layer compared to Examples 1-5. In addition, the boron nitride content in the boron nitride thermal conductive layer in Comparative Examples 1-2 is reduced. As a result, the resulting silicone rubber composite film has a low in-plane thermal conductivity and low electromagnetic shielding performance.

[0146] c) In Example 2, compared with Example 1, the content of each filler in the carbon nanotube conductive shielding layer, the ferroferric oxide magnetic shielding layer, and the boron nitride thermal conductive layer is increased, and the electromagnetic shielding effectiveness and thermal conductivity of the silicone rubber composite film are increased;

[0147] d) Compared with Example 2, Example 3 has a higher nickel content in the nickel-plated glass fiber cloth layer, and the electromagnetic shielding effectiveness of the silicone rubber composite film is improved;

[0148] e) In Example 4, compared with Example 3, the content of each filler in the carbon nanotube conductive shielding layer, the ferroferric oxide magnetic shielding layer, and the boron nitride thermal conductive layer is increased, and the electromagnetic shielding effectiveness and thermal conductivity of the silicone rubber composite film are increased;

[0149] f) In Example 5, compared with Example 4, the content of each filler in the carbon nanotube conductive shielding layer, the ferroferric oxide magnetic shielding layer, and the boron nitride thermal conductive layer is increased, and the electromagnetic shielding effectiveness and thermal conductivity of the silicone rubber composite film are increased;

[0150] In summary, the thermally conductive electromagnetic shielding silicone rubber multilayer composite film of the present invention has excellent thermal conductivity and electromagnetic shielding performance. This is because hexagonal boron nitride is easily oriented in the thermal conductive layer, and thus a thermal conductive path is easily formed in the thermal conductive layer, thereby improving the thermal conductivity. The ferroferric oxide nanoparticles added to the composite film are magnetic and are evenly dispersed in the magnetic shielding layer to provide magnetic loss. Carbon nanotubes can form conductive paths in the conductive shielding layer, significantly improving the conductivity of the silicone rubber and providing dielectric loss. The composite film contains nickel-plated glass fiber cloth, and the nickel content on the glass fiber cloth can be changed by changing the plating solution concentration and the nickel plating time, thereby regulating the electromagnetic parameters and changing the electromagnetic shielding effectiveness of the nickel-plated glass fiber cloth layer. In addition, the preparation process of the thermally conductive electromagnetic shielding silicone rubber multilayer composite film is simple, safe and environmentally friendly, and also has good elasticity and mechanical properties. It can be widely used in 5G communications, consumer electronics, power batteries, national defense and military industries and other fields.

[0151] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A thermally conductive electromagnetic shielding silicone rubber multilayer composite film, characterized in that: It comprises a nickel-plated glass fiber cloth, a magnetic shielding layer, a conductive shielding layer and a heat-conducting layer stacked in sequence; the magnetic shielding layer is a silicone rubber layer containing magnetic fillers; The conductive shielding layer is a silicone rubber layer containing conductive fillers; the thermal conductive layer is a silicone rubber layer containing thermal conductive fillers; the magnetic filler is at least one of ferroferric oxide powder, zinc manganese ferrite powder, and cobalt ferrite powder; the conductive filler is at least one of carbon nanotubes, graphene nanosheets, fullerenes, and MXene nanosheets; the thermal conductive filler is at least one of hexagonal boron nitride, aluminum oxide powder, and aluminum nitride powder.

2. The thermally conductive electromagnetic shielding silicone rubber multilayer composite film according to claim 1, characterized in that: The nickel content of the nickel-plated glass fiber cloth is 5 wt % to 30 wt %.

3. The thermally conductive electromagnetic shielding silicone rubber multilayer composite film according to claim 1, characterized in that: The particle size of the magnetic filler is 10nm to 200nm.

4. The thermally conductive electromagnetic shielding silicone rubber multilayer composite film according to claim 1, characterized in that: The particle size of the thermal conductive filler is 1 μm to 100 μm.

5. The thermally conductive electromagnetic shielding silicone rubber multilayer composite film according to any one of claims 1 to 4, characterized in that: The thickness of the nickel-plated glass fiber cloth is 0.03 mm to 0.10 mm; the thickness of the magnetic shielding layer is 0.1 mm to 1.0 mm; the thickness of the conductive shielding layer is 0.1 mm to 1.0 mm; and the thickness of the heat-conducting layer is 0.1 mm to 1.0 mm.

6. The thermally conductive electromagnetic shielding silicone rubber multilayer composite film according to any one of claims 1 to 4, characterized in that: The thermal conductive electromagnetic shielding silicone rubber multilayer composite film comprises the following raw materials in parts by weight: Vinyl silicone oil: 80 to 100 parts; Hydrogenated silicone oil: 1 to 5 parts; Platinum catalyst: 0.1 to 0.5 parts; Inhibitor: 0.001 to 0.02 parts; Magnetic filler: 5 to 60 parts; Conductive filler: 2 to 12 parts; Thermal conductive filler: 30 to 100 parts; Nickel-plated glass fiber cloth: 0.01 to 1 part.

7. The thermally conductive electromagnetic shielding silicone rubber multilayer composite film according to claim 6, characterized in that: The viscosity of the vinyl silicone oil is 50mPa·s to 2000mPa·s; the hydrogen content of the hydrogen-containing silicone oil is 0.1wt% to 1.0wt%; the platinum catalyst is at least one of a methylvinylsiloxane-platinum complex, an isopropanol solution of chloroplatinic acid, a platinum-tetrahydrofuran complex, and a vinylpolysiloxane-platinum complex; and the inhibitor is at least one of ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, and 3,6-dimethyl-1-heptyn-3-ol.

8. A method for preparing a thermally conductive electromagnetic shielding silicone rubber multilayer composite film according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1) vinyl silicone oil, hydrogenated silicone oil, magnetic filler, platinum catalyst and inhibitor are mixed, coated on one side of nickel-plated glass fiber cloth, and then vulcanized to obtain a double-layer composite film containing a magnetic shielding layer and nickel-plated glass fiber cloth; 2) mixing vinyl silicone oil, hydrogenated silicone oil, conductive filler, platinum catalyst and inhibitor, coating the mixture on the surface of the magnetic shielding layer, and vulcanizing the mixture to obtain a three-layer composite film comprising a conductive shielding layer, a magnetic shielding layer and nickel-plated glass fiber cloth; 3) Vinyl silicone oil, hydrogenated silicone oil, thermal conductive filler, platinum catalyst and inhibitor are mixed and coated on the surface of the conductive shielding layer, and then vulcanized to obtain a four-layer composite film comprising a thermal conductive layer, a conductive shielding layer, a magnetic shielding layer and nickel-plated glass fiber cloth, i.e., a thermal conductive electromagnetic shielding silicone rubber multilayer composite film.

9. An electronic device, characterized in that: The invention comprises the heat-conducting electromagnetic shielding silicone rubber multilayer composite film according to any one of claims 1 to 7.

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