Preparation method of thermocuring bonding conductive shielding film, shielding film and application

Abstract

The invention provides a preparation method of a thermocuring bonding conductive shielding film, the shielding film and application. The preparation method of the shielding film comprises the following steps: diluting vinyl silicone oil into an organic silicon solution by using an organic solvent, adding hydrogen-containing silicone oil, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) hexane, an adhesion promoter, a platinum catalyst and a graphite material, and stirring to obtain a mixed sizing material; coating one side of a copper foil with the mixed sizing material, baking at the temperature of 40-65 DEG C to obtain a first semi-solid sheet, covering the first semi-solid sheet with a first release film, coating the other side of the copper foil with the mixed sizing material, baking at the temperature of 40-65 DEG C to obtain a second semi-solid sheet, covering the second semi-solid sheet with a second release film, and refrigerating. The prepared thermocuring bonding conductive shielding film has good bonding force and shielding performance, is soft, can be well attached to the surface of a metal target piece, is tight in sealing, is thin in application thickness, and can save space.

Description

Technical Field

[0001] This invention relates to the field of organosilicon shielding film technology, and in particular to a method for preparing a thermosetting adhesive conductive shielding film for use in electronic devices, and the thermosetting adhesive conductive shielding film itself. Background Technology

[0002] With the rapid development of technology, electronic devices are becoming increasingly miniaturized and high-performance, significantly increasing the electronic integration within these devices and narrowing the distance between them. This places higher demands on addressing electromagnetic interference. It is well known that electromagnetic radiation has adverse effects on the normal operation of surrounding equipment and even on living organisms. Filling the casing or chassis connections of electronic devices with conductive materials can effectively provide shielding.

[0003] Currently, commonly used conductive shielding and sealing materials include silicone rubber and FIP conductive adhesive. Conductive silicone rubber is often die-cut, molded, or extruded into a specific shape or size, and connected by adhesive backing or screw positioning, requiring a relatively large space. FIP conductive adhesive can be automatically dispensed, which is highly efficient and can meet the requirements of shielding shells for microstructures. However, it requires a high degree of automation in the equipment, is prone to overflow, and is difficult to clean. Furthermore, the shielding effectiveness of conventional FIP conductive adhesive decreases significantly after long-term thermal shock testing, making it unsuitable for certain high-performance applications, such as base stations. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a method for preparing a thermosetting adhesive conductive shielding film, the shielding film itself, and its applications. The resulting thermosetting adhesive conductive shielding film requires no adhesive backing or screws, enabling simple connection to electronic devices. It is convenient to use, requires minimal space, and offers high reliability.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a thermosetting adhesive conductive shielding film, comprising the steps of: (1) Mixing Vinyl silicone oil is diluted with an organic solvent to form an organosilicon solution. Hydrogen-containing silicone oil, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, an adhesion promoter, a platinum catalyst, and graphite are added and stirred to obtain a mixed adhesive. The weight ratio of the hydrogen-containing silicone oil to the 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane is 0.08~0.19. The graphite is nickel-coated graphite powder or polyaniline-modified nickel-coated graphite powder. (2) Film making The mixed adhesive is coated on one side of a copper foil and baked at 40-65°C to obtain a first semi-solid sheet. A first release film is then covered on the first semi-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 40-65°C to obtain a second semi-solid sheet. A second release film is then covered on the second semi-solid sheet and refrigerated.

[0006] This invention, based on conventional silicone shielding films, selects hydrogen-containing silicone oil and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane as the crosslinking agents in a compound formulation. Baking at 40-65°C allows the hydrogen-containing silicone oil to preferentially undergo a crosslinking reaction, resulting in a semi-solid film. Subsequent heating and curing during use allows the 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane to undergo a further crosslinking reaction. Thus, the semi-solid film can be tightly adhered to metal targets such as electronic devices through a simple pressurized and heated method. Furthermore, controlling the weight ratio of hydrogen-containing silicone oil to 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane to 0.08-0.19, a certain amount of hydrogen-containing silicone oil ensures that the formed semi-solid film has sufficient strength for easy removal and repeated peeling, with a smooth, defect-free surface. After pressurized and heated curing, it exhibits strong adhesion to the metal target, providing good shielding performance when used as a conductive shielding film. Polyaniline-modified nickel-coated graphite powder, compared to conventional nickel-coated graphite powder, provides shielding films with better resistance to thermal shock and superior shielding performance. This invention, by adjusting the curing method, employs a semi-curing process using hydrogen-containing silicone oil followed by full curing with 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane. This eliminates the need for adhesive backing, achieving excellent adhesion and flexibility, allowing for excellent bonding to the surface of metal components, providing a tight seal. Furthermore, its thin application thickness saves space.

[0007] As a technical solution of the present invention, by weight, the vinyl silicone oil is 10-30 parts, the hydrogen-containing silicone oil is 0.05-1.00 parts, the 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane is 2-6 parts, the adhesion promoter is 0.5-5.0 parts, the platinum catalyst is 0.01-0.03 parts, and the graphite is 80-100 parts.

[0008] As one technical solution of the present invention, the viscosity of the vinyl silicone oil is 200,000~500,000 cP and the vinyl content is 0.02~1.00%.

[0009] As one technical solution of the present invention, the organic solvent is selected from toluene, xylene, stain remover, dimethyl ether or acetone.

[0010] As one technical solution of the present invention, the content of vinyl silicone oil in the organosilicon solution is 20~40 wt.%.

[0011] As one technical solution of the present invention, the viscosity of the hydrogen-containing silicone oil is 50~300 cP and the hydrogen content is 0.02~0.10%.

[0012] As a technical solution of the present invention, the preparation of the polyaniline-modified nickel-coated graphite powder includes: preparing polyaniline into a polyaniline solution, adding the nickel-coated graphite powder, mixing, and then spray drying.

[0013] As one technical solution of the present invention, the particle size of the nickel-coated graphite powder is 5~20μm.

[0014] The second aspect of the present invention provides a thermosetting adhesive conductive shielding film prepared by the aforementioned method, comprising a first release film, a first half-solid sheet, a copper foil, a second half-solid sheet, and a second release film stacked sequentially.

[0015] The third aspect of the present invention provides the application of the aforementioned thermosetting adhesive conductive shielding film on electronic devices, wherein the first release film and the second release film on the thermosetting adhesive conductive shielding film are peeled off and attached to the electronic device, and then baked at a pressure of 0.5~1.0MPa and a temperature of 130~170°C. Detailed Implementation

[0016] The thermosetting adhesive conductive shielding film of the present invention has excellent shielding and adhesion properties. It can be adhered to the outer shell or chassis connection of electronic devices and filled with conductive material to effectively play a shielding role.

[0017] The thermosetting adhesive conductive shielding film of the present invention comprises a first release film, a first semi-solid sheet, a copper foil, a second semi-solid sheet, and a second release film stacked sequentially. The first and second release films can be fluorinated release films with a thickness of 0.05~0.10 mm. The first and second semi-solid sheets are organosilicon containing graphite, and are semi-cured, i.e., in a weakly cured state, possessing certain strength, capable of being demolded, and repeatedly peeled from the application surface, while also exhibiting a certain degree of adhesion. The copper foil has a thickness of 0.010~0.025 mm.

[0018] When the thermosetting adhesive conductive shielding film of the present invention is applied to electronic devices, the first and second release films on the thermosetting adhesive conductive shielding film are peeled off, and then the film is attached to the electronic device and baked at a pressure of 0.5~1.0 MPa and a temperature of 130~170°C. As examples, the pressure can be, but is not limited to, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, or 1.0 MPa. The temperature can be, but is not limited to, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, or 170°C. The baking time is 10~45 min; as examples, the time can be, but is not limited to, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, or 45 min. After baking, the first semi-solid sheet is completely cured and has a thickness of 0.08~0.15 mm.

[0019] The method for preparing the thermosetting adhesive conductive shielding film of the present invention includes the following steps.

[0020] (1) Mixing Vinyl silicone oil is diluted with an organic solvent to form an organosilicon solution. Hydrogen-containing silicone oil, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, adhesion promoter, platinum catalyst and graphite are added and stirred to obtain a mixed adhesive.

[0021] (2) Film making The mixed adhesive is coated on one side of the copper foil and baked at 40~75°C to obtain the first semi-solid sheet. The first semi-solid sheet is covered with a first release film. The mixed adhesive is coated on the other side of the copper foil and baked at 40~75°C to obtain the second semi-solid sheet. The second semi-solid sheet is covered with a second release film and refrigerated.

[0022] The composition, by weight, comprises 10-30 parts vinyl silicone oil, 0.05-1.00 parts hydrogen-containing silicone oil, 2-6 parts 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 0.5-5.0 parts grafting accelerator, 0.01-0.03 parts platinum catalyst, and 80-100 parts graphite. Preferably, the composition comprises 11-25 parts vinyl silicone oil, 0.8-1.0 parts hydrogen-containing silicone oil, 4.5-5.5 parts 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 3.6-4.8 parts grafting accelerator, 0.01-0.03 parts platinum catalyst, and 85-91 parts graphite. More preferably, the composition comprises 20-25 parts vinyl silicone oil, 0.10-0.50 parts hydrogen-containing silicone oil, 2-4 parts 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 0.100-3.000 parts graft accelerator, 0.02-0.03 parts platinum catalyst, and 85-91 parts graphite. Even more preferably, the composition comprises 20-25 parts vinyl silicone oil, 0.10-0.30 parts hydrogen-containing silicone oil, 2-3 parts 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 0.500-1.500 parts graft accelerator, 0.02-0.03 parts platinum catalyst, and 85-91 parts graphite. The weight ratio of hydrogen-containing silicone oil to 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane is 0.08-0.19. For example, the weight ratio may be, but is not limited to, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, or 0.19. The vinyl silicone oil has a viscosity of 200,000–500,000 cP and a vinyl content of 0.02–1.00%. The organic solvent is selected from toluene, xylene, detergent, dimethyl ether, or acetone. The vinyl silicone oil content in the silicone solution is 20–40 wt.%. The hydrogen-containing silicone oil has a viscosity of 50–300 cP and a hydrogen content of 0.02–0.10%.

[0023] The adhesion promoter can be a conventionally known tackifier, such as an organic compound having two or more alkoxysilanes in the molecule represented by a reaction mixture of an amino-containing organoalkoxysilane and an epoxy-containing organoalkoxysilane, an epoxy-containing silane or its partially hydrolyzed condensate, and two or more tackifiers selected from these can be used in combination, preferably. Further, the adhesion promoter can be an epoxy-containing silane or its partially hydrolyzed condensate and an alkoxysilane compound. The epoxy-containing silane or its partially hydrolyzed condensate can be 3-epoxypropoxyprolyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane. The alkoxysilane compound can be 1,6-bis(trimethoxysilyl)hexane, 1,6-bis(trimethoxysilyl)hexane, etc. Disilanes such as ethoxysilyl hexane, 1,4-bis(trimethoxysilyl)hexane, 1,5-bis(trimethoxysilyl)hexane, 2,5-bis(trimethoxysilyl)hexane, 1-methyldimethoxysilyl-6-trimethoxysilylhexane, 1-phenyldiethoxysilyl-6-triethoxysilylhexane, and 1,6-bis(methyldimethoxysilyl)hexane. The platinum catalyst is a platinum-containing catalyst, which can be any known catalyst, and may further include finely powdered platinum, platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, chloroplatinic acid / diene complexes, platinum / olefin complexes, platinum / carbonyl complexes, chloroplatinic acid / tetravinyltetramethylcyclotetrasiloxane complexes, platinum / olefinic siloxane complexes, platinum / divinyltetramethyldisiloxane complexes and platinum / tetravinyltetramethylcyclotetrasiloxane complexes, complexes of chloroplatinic acid and ethynyl alcohol, and mixtures of two or more of these types. The graphite material is nickel-coated graphite powder or polyaniline-modified nickel-coated graphite powder. Baking at 40–65°C for 10–40 min yields the first or second half-solid sheet. All raw materials are stirred evenly with a mixer and filtered through an 80-mesh filter for later use.

[0024] The preparation of polyaniline-modified nickel-coated graphite powder includes: preparing a polyaniline solution with polyaniline, adding the nickel-coated graphite powder, mixing, and then spray drying. The polyaniline solution is prepared by dissolving polyaniline in an organic solvent, such as toluene, xylene, dimethyl ether, or acetone. The particle size of the nickel-coated graphite powder is 5-20 μm. This modification method is relatively simple, eliminating the need for acid washing and ball milling, thus avoiding damage to the structure of the nickel-coated graphite powder and reduction in its conductivity. This modification method, by directly spray-drying the mixture of polyaniline solution and nickel-coated graphite powder, yields composite conductive particles loaded on polyaniline. This improves the conductivity of the powder while enhancing the thermal shock resistance of the nickel-coated graphene, allowing it to be used in harsher environments.

[0025] Furthermore, the mixed adhesive can be applied to both sides of the copper foil using a coating machine. After semi-curing at 40~65℃, a release film is then applied. Before use, the release film is removed, and the film is adhered to the surface of the electronic device. Full curing at 130~170℃ ensures a tight bond between the conductive shielding film and the electronic device surface. Before use, the thermosetting conductive shielding film should be refrigerated at 0~4℃.

[0026] To better illustrate the purpose, technical solution, and beneficial effects of this invention, the invention will be further described below with reference to specific embodiments. It should be noted that the methods described below are further explanations of this invention and should not be construed as limiting it.

[0027] Example 1 This embodiment is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0028] (1) Mixing 25g of vinyl silicone oil (viscosity 300,000 cP, vinyl content 0.08%) was diluted with 58.33g of xylene to prepare an organosilicon solution. Then, 0.8g of hydrogen-containing silicone oil (viscosity 100 cP, hydrogen content 0.06%), 4.5g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 4.8g of adhesion promoter, 0.025g of platinum catalyst (platinum content 1000 ppm), and 85g of nickel-coated graphite powder (particle size 10 μm) were added and stirred to obtain a mixed adhesive. The adhesion promoter was a reactant of 3-epoxypropoxypropylmethyldimethoxysilane and 1,4-bis(trimethoxysilyl)hexane in a weight ratio of 60:40.

[0029] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 60°C for 30 min to obtain a first half-solid sheet. A first release film (fluorine release film, 0.08 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 60°C for 30 min to obtain a second half-solid sheet. A second release film (fluorine release film, 0.08 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0030] Example 2 This embodiment is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0031] (1) Mixing 11g of vinyl silicone oil (viscosity 300,000 cP, vinyl content 0.08%) was diluted with 25.67g of xylene to prepare an organosilicon solution. Then, 1.0g of hydrogen-containing silicone oil (viscosity 100 cP, hydrogen content 0.06%), 5.3g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 4.3g of adhesion promoter, 0.030g of platinum catalyst (platinum content 1000 ppm), and 91g of nickel-coated graphite powder (particle size 10 μm) were added and stirred to obtain a mixed adhesive. The adhesion promoter was a reactant of 3-epoxypropoxypropylmethyldimethoxysilane and 1,4-bis(trimethoxysilyl)hexane in a weight ratio of 60:40.

[0032] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 60°C for 30 min to obtain a first half-solid sheet. A first release film (fluorine release film, 0.08 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 60°C for 30 min to obtain a second half-solid sheet. A second release film (fluorine release film, 0.08 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0033] Example 3 This embodiment is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0034] (1) Mixing 20g of vinyl silicone oil (viscosity 300,000 cP, vinyl content 0.08%) was diluted with 46.67g of xylene to prepare an organosilicon solution. Then, 0.6g of hydrogen-containing silicone oil (viscosity 100 cP, hydrogen content 0.06%), 5.5g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 3.6g of adhesion promoter, 0.03g of platinum catalyst (platinum content 1000 ppm), and 90.3g of nickel-coated graphite powder (particle size 10 μm) were added and stirred to obtain a mixed adhesive. The adhesion promoter was a reactant of 3-epoxypropoxypropylmethyldimethoxysilane and 1,4-bis(trimethoxysilyl)hexane in a weight ratio of 60:40.

[0035] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 60°C for 30 min to obtain a first half-solid sheet. A first release film (fluorine release film, 0.08 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 60°C for 30 min to obtain a second half-solid sheet. A second release film (fluorine release film, 0.08 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0036] Example 4 This embodiment is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0037] (1) Mixing 20g of vinyl silicone oil (viscosity 300,000 cP, vinyl content 0.08%) was diluted with 46.67g of xylene to prepare an organosilicon solution. Then, 0.45g of hydrogen-containing silicone oil (viscosity 100 cP, hydrogen content 0.06%), 5.5g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 3.6g of adhesion promoter, 0.03g of platinum catalyst (platinum content 1000 ppm), and 90.3g of nickel-coated graphite powder (particle size 10 μm) were added and stirred to obtain a mixed adhesive. The adhesion promoter was a reactant of 3-epoxypropoxypropylmethyldimethoxysilane and 1,4-bis(trimethoxysilyl)hexane in a weight ratio of 60:40.

[0038] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 60°C for 30 min to obtain a first half-solid sheet. A first release film (fluorine release film, 0.08 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 60°C for 30 min to obtain a second half-solid sheet. A second release film (fluorine release film, 0.08 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0039] Example 5 This embodiment is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0040] (1) Mixing Take 20g of vinyl silicone oil (viscosity 300,000 cP, vinyl content 0.08%) and dilute it with 46.67g of xylene to prepare an organosilicon solution. Add 0.45g of hydrogen-containing silicone oil (viscosity 100 cP, hydrogen content 0.06%), 5.5g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 3.6g of adhesion promoter, 0.03g of platinum catalyst (platinum content 1000ppm), and 90.3g of polyaniline-modified nickel-coated graphite powder (stir to obtain a mixed adhesive). The adhesion promoter is a reactant of 3-epoxypropoxypropylmethyldimethoxysilane and 1,4-bis(trimethoxysilyl)hexane in a weight ratio of 60:40.

[0041] The preparation method of polyaniline modified nickel-coated graphite powder is as follows: take 20g of polyaniline, add xylene and stir evenly to prepare a 5wt.% polyaniline solution, then add 100g of nickel-coated graphite powder (particle size of 10μm), and after stirring evenly, use a spray dryer to obtain modified nickel-coated graphite powder.

[0042] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 60°C for 30 min to obtain a first half-solid sheet. A first release film (fluorine release film, 0.08 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 60°C for 30 min to obtain a second half-solid sheet. A second release film (fluorine release film, 0.08 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0043] Example 6 This embodiment is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0044] (1) Mixing 20g of vinyl silicone oil (viscosity 450,000 cP, vinyl content 0.06%) was diluted with 70.50g of acetone to prepare an organosilicon solution. Then, 0.8g of hydrogen-containing silicone oil (viscosity 250 cP, hydrogen content 0.04%), 4.5g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 4.8g of adhesion promoter, 0.025g of platinum catalyst (platinum content 800 ppm), and 85g of nickel-coated graphite powder (particle size 15 μm) were added and stirred to obtain a mixed adhesive. The adhesion promoter was a reactant of 3-epoxypropoxypropylmethyldimethoxysilane and 1,4-bis(trimethoxysilyl)hexane in a weight ratio of 50:50.

[0045] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 50°C for 40 min to obtain the first half-solid sheet. A first release film (fluorine release film, 0.10 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 50°C for 35 min to obtain the second half-solid sheet. A second release film (fluorine release film, 0.10 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0046] Example 7 This embodiment is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0047] (1) Mixing 15g of vinyl silicone oil (viscosity 300,000 cP, vinyl content 0.08%) was diluted with 45.38g of xylene to prepare an organosilicon solution. Then, 0.5g of hydrogen-containing silicone oil (viscosity 100 cP, hydrogen content 0.06%), 4.5g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2.5g of adhesion promoter, 0.025g of platinum catalyst (platinum content 1000 ppm), and 80g of nickel-coated graphite powder (particle size 10 μm) were added and stirred to obtain a mixed adhesive. The adhesion promoter was a reactant of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 1-methyldimethoxysilyl-6-trimethoxysilylhexane in a weight ratio of 50:50.

[0048] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 50°C for 40 min to obtain a first half-solid sheet. A first release film (fluorine release film, 0.08 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 50°C for 40 min to obtain a second half-solid sheet. A second release film (fluorine release film, 0.08 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0049] Comparative Example 1 This comparative example is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0050] (1) Mixing 25g of vinyl silicone oil (viscosity 300,000 cP, vinyl content 0.08%) was diluted with 58.33g of xylene to prepare an organosilicon solution. Then, 2.8g of hydrogen-containing silicone oil (viscosity 100 cP, hydrogen content 0.06%), 4.8g of adhesion promoter, 0.025g of platinum catalyst (platinum content 1000 ppm), and 85g of nickel-coated graphite powder (particle size 10 μm) were added and stirred to obtain a mixed adhesive. The adhesion promoter was a reactant of 3-epoxypropoxypropylmethyldimethoxysilane and 1,4-bis(trimethoxysilyl)hexane in a weight ratio of 60:40.

[0051] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 60°C for 30 min to obtain a first half-solid sheet. A first release film (fluorine release film, 0.08 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 60°C for 30 min to obtain a second half-solid sheet. A second release film (fluorine release film, 0.08 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0052] Comparative Example 2 This comparative example is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0053] (1) Mixing 25g of vinyl silicone oil (viscosity 300,000 cP, vinyl content 0.08%) was diluted with 58.33g of xylene to prepare an organosilicon solution. Then, 0.1g of hydrogen-containing silicone oil (viscosity 100 cP, hydrogen content 0.06%), 4.5g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 4.8g of adhesion promoter, 0.025g of platinum catalyst (platinum content 1000 ppm), and 85g of nickel-coated graphite powder (particle size 10 μm) were added and stirred to obtain a mixed adhesive. The adhesion promoter was a reactant of 3-epoxypropoxypropylmethyldimethoxysilane and 1,4-bis(trimethoxysilyl)hexane in a weight ratio of 60:40.

[0054] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 60°C for 30 min to obtain a first half-solid sheet. A first release film (fluorine release film, 0.08 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 60°C for 30 min to obtain a second half-solid sheet. A second release film (fluorine release film, 0.08 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0055] Comparative Example 3 This comparative example is a thermosetting adhesive conductive shielding film, the preparation method of which includes the following steps.

[0056] (1) Mixing 25g of vinyl silicone oil (viscosity 300,000 cP, vinyl content 0.08%) was diluted with 58.33g of xylene to prepare an organosilicon solution. Then, 2.0g of hydrogen-containing silicone oil (viscosity 100 cP, hydrogen content 0.06%), 4.5g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 4.8g of adhesion promoter, 0.025g of platinum catalyst (platinum content 1000 ppm), and 85g of nickel-coated graphite powder (particle size 10 μm) were added and stirred to obtain a mixed adhesive. The adhesion promoter was a reactant of 3-epoxypropoxypropylmethyldimethoxysilane and 1,4-bis(trimethoxysilyl)hexane in a weight ratio of 60:40.

[0057] (2) Film making The mixed adhesive is coated on one side of a copper foil (0.015 mm thick) and baked at 60°C for 30 min to obtain a first half-solid sheet. A first release film (fluorine release film, 0.08 mm thick) is then covered on the first half-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 60°C for 30 min to obtain a second half-solid sheet. A second release film (fluorine release film, 0.08 mm thick) is then covered on the second half-solid sheet and refrigerated at 0~4°C.

[0058] Performance tests were conducted on the thermosetting adhesive conductive shielding films of Examples 1-7 and Comparative Examples 1-3, and the results are shown in Table 1. The test conditions are as follows.

[0059] Adhesion test: The first release film of the thermosetting adhesive conductive shielding film of Examples 1-7 and Comparative Examples 1-3 was peeled off and attached to a clean aluminum plate. Then the second release film was peeled off and another aluminum plate was placed on top. A pressure of 0.5-1 MPa was applied using a hot press and heated at 150°C for 30 minutes. The samples were then cooled to room temperature to obtain samples. The adhesion of the prepared samples was then tested using a tensile testing machine.

[0060] Shielding performance test: The dual-cavity method (MIL-DTL-83528C) was used.

[0061] Thermal shock conditions: thermal shock chamber at -40~125℃, holding time at each temperature is 30min, and heating time is about 11℃ / min.

[0062] Visual inspection: Visually inspect the appearance of the prepared sample. Table 1 Performance of thermosetting adhesive conductive shielding films in Examples 1-7 and Comparative Examples 1-3

[0063] As shown in Table 1, using hydrogen-containing silicone oil and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane as the crosslinking agents, and controlling their ratio, results in a shielding film with a smooth, defect-free surface and good shielding effect and adhesion. Furthermore, selecting polyaniline-modified nickel-coated graphite powder can impart better thermal shock resistance to the shielding film, leading to improved shielding performance.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a thermosetting adhesive conductive shielding film, characterized in that, Including the following steps: (1) Mixing Vinyl silicone oil is diluted with an organic solvent to form an organosilicon solution. Hydrogen-containing silicone oil, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, an adhesion promoter, a platinum catalyst, and graphite are added and stirred to obtain a mixed adhesive. The weight ratio of the hydrogen-containing silicone oil to the 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane is 0.08~0.

19. The graphite is nickel-coated graphite powder or polyaniline-modified nickel-coated graphite powder. (2) Film making The mixed adhesive is coated on one side of a copper foil and baked at 40-65°C to obtain a first semi-solid sheet. A first release film is then covered on the first semi-solid sheet. The mixed adhesive is coated on the other side of the copper foil and baked at 40-65°C to obtain a second semi-solid sheet. A second release film is then covered on the second semi-solid sheet and refrigerated.

2. The method for preparing the thermosetting adhesive conductive shielding film according to claim 1, characterized in that, By weight, the vinyl silicone oil is 10-30 parts, the hydrogen-containing silicone oil is 0.05-1.00 parts, the 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane is 2-6 parts, the adhesion promoter is 0.5-5.0 parts, the platinum catalyst is 0.01-0.03 parts, and the graphite is 80-100 parts.

3. The method for preparing the thermosetting adhesive conductive shielding film according to claim 1, characterized in that, The vinyl silicone oil has a viscosity of 200,000 to 500,000 cP and a vinyl content of 0.02 to 1.00%.

4. The method for preparing the thermosetting adhesive conductive shielding film according to claim 1, characterized in that, The organic solvent is selected from toluene, xylene, stain remover, dimethyl ether, or acetone.

5. The method for preparing the thermosetting adhesive conductive shielding film according to claim 1, characterized in that, The content of vinyl silicone oil in the organosilicon solution is 20~40 wt.%.

6. The method for preparing the thermosetting adhesive conductive shielding film according to claim 1, characterized in that, The hydrogen-containing silicone oil has a viscosity of 50~300 cP and a hydrogen content of 0.02~0.10%.

7. The method for preparing the thermosetting adhesive conductive shielding film according to claim 1, characterized in that, The preparation of the polyaniline-modified nickel-coated graphite powder includes: preparing polyaniline into a polyaniline solution, adding the nickel-coated graphite powder, mixing, and then spray drying.

8. The method for preparing the thermosetting adhesive conductive shielding film according to claim 1 or 7, characterized in that, The particle size of the nickel-coated graphite powder is 5~20μm.

9. The thermosetting adhesive conductive shielding film prepared by the method for preparing the thermosetting adhesive conductive shielding film according to any one of claims 1 to 8, characterized in that, It includes a first release film, a first half-solid sheet, a copper foil, a second half-solid sheet, and a second release film stacked in sequence.

10. The application of the thermosetting adhesive conductive shielding film according to claim 9 in electronic devices, characterized in that, After peeling off the first and second release films from the thermosetting adhesive conductive shielding film, they are attached to the electronic device and then baked at a pressure of 0.5~1.0MPa and a temperature of 130~170℃.

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