PI organic silicon composite material and preparation method thereof

Abstract

The invention relates to the technical field of organic silicon composite materials, in particular to a PI organic silicon composite material and a preparation method thereof. The middle layer is a bottom coating; the surface layer is a silica gel coating, and the silica gel coating comprises a surface layer and a bonding layer; the outermost layer is a surface treatment layer, a silane coupling agent in the bottom coating forms a chemical bond with PI through an organic functional group of the silane coupling agent, and a silica group is cross-linked with the silica gel layer, so that a strong interface structure is formed. The fumed silica added in the silica gel layer enhances the mechanical properties of the material, and the large specific surface area and abundant surface hydroxyl groups of the fumed silica help to improve the thermal stability and flame retardancy of the material. The surface layer silica gel and the bonding layer silica gel are provided with cross-linking agents and functional additives in different proportions, and perfect balance of flexibility and durability is achieved by regulating and controlling intermolecular acting force and a network structure.

Description

Technical Field

[0001] The present invention relates to the technical field of organic silicon composite materials, and in particular to a PI organic silicon composite material and a preparation method thereof. Background Art

[0002] With the rapid development of science and technology, the demand for high-performance composite materials in aerospace, 5G communications, flexible electronics and other fields is becoming increasingly urgent. In these extreme application environments, materials not only need to have excellent basic properties such as high temperature resistance, insulation, and flexibility, but also need to be able to cope with multiple challenges such as chemical corrosion, thermal cycling, and electromagnetic interference. Although traditional polyimide (PI) materials have excellent high temperature resistance and insulation properties, they still have deficiencies in flexibility, surface properties and versatility.

[0003] In the prior art, common methods for improving the performance of PI materials include surface modification and the addition of composite fillers. However, these methods can often only improve one aspect of the material's performance, and it is difficult to achieve a synergistic improvement of multiple properties. For example, the addition of inorganic fillers can improve the heat resistance and mechanical properties of PI, but at the same time it will reduce its flexibility and dielectric properties. On the other hand, silicone materials have attracted much attention due to their excellent flexibility, weather resistance and surface properties, but their high temperature resistance and mechanical strength are relatively poor.

[0004] Therefore, how to organically combine the advantages of PI and silicone materials to develop a composite material with excellent performance in multiple extreme environments has become an urgent problem to be solved by technicians in this field. Summary of the invention

[0005] The present invention proposes an innovative PI silicone composite material and its preparation method, which cleverly solves the above technical problems through a carefully designed multi-layer structure and a unique formula. The material uses PI as the bottom layer, providing an excellent high temperature resistance and insulation foundation; through a special primer treatment, the interface bonding between PI and the upper silicone is enhanced; the double-layer silicone structure is adopted to achieve differentiated optimization of surface performance and internal performance; finally, through surface treatment, the surface properties of the material are further improved.

[0006] The object of the present invention is to provide a PI organic silicon composite material, comprising the following hierarchical structure:

[0007] The bottom layer is a polyimide film;

[0008] The middle layer is the base coat;

[0009] The surface layer is a silicone coating, and the silicone coating includes a surface layer and a bonding layer;

[0010] The outermost layer is the surface treatment layer.

[0011] Specifically, the primer layer is composed of the following components in parts by weight:

[0012] 60-70 parts of polysiloxane, 15-20 parts of silane coupling agent, 5-8 parts of wetting agent, 5-7 parts of impurity scavenger, and the balance to 100 parts of solvent.

[0013] Specifically, the polysiloxane is methylphenyl polysiloxane, the silane coupling agent is γ-aminopropyltriethoxysilane, the wetting agent is polyether-modified polysiloxane, the impurity scavenger is cyclohexanone, and the solvent is a mixed solvent of ethyl acetate and xylene in a volume ratio of 1:1.

[0014] Specifically, the surface layer is composed of the following components in parts by weight:

[0015] 55-65 parts of methyl vinyl silicone rubber, 20-25 parts of fumed silica, 2-4 parts of polyether modified polydimethylsiloxane, 4-6 parts of cyclic siloxane, 0.3-0.7 parts of organic peroxide, 1-3 parts of triethoxysilane, 0.5-2 parts of low boiling point mixture, 0.15-0.25 parts of platinum vulcanizer, 0.03-0.07 parts of tackifier, 0.08-0.12 parts of antistatic agent, 2-4 parts of fluff powder, 0.6-1 parts of matting powder, 0.08-0.12 parts of dispersant.

[0016] Specifically, compared with the surface layer, the content of fumed silica in the bonding layer is increased to 25-30 parts by weight, and the cyclic siloxane is replaced by 5-7 parts by weight of a 1:1 weight ratio mixture of hexamethylcyclotrisilazane and octamethylcyclotetrasiloxane.

[0017] Specifically, the surface treatment layer is composed of the following components in parts by weight:

[0018] 45-55 parts of dimethylpolysiloxane, 6-10 parts of silicon dioxide, 25-35 parts of dodecane, 3-7 parts of polysiloxane.

[0019] The method for preparing the PI organic silicon composite material comprises the following steps:

[0020] (1) Primer treatment: Apply a primer treatment agent on the surface of the polyimide film and cure it;

[0021] (2) Silicone coating: coating the surface layer silicone and the bonding layer silicone on the polyimide film treated with primer in sequence and curing them;

[0022] (3) Surface treatment: Apply a surface treatment agent on the surface of the silicone coating and cure it.

[0023] Specifically, the primer treatment step includes:

[0024] (1) Use a sponge to soak the primer and apply it evenly on the surface of the polyimide film using a laminating method. The coating amount is controlled to be 13-17g / m 2 ;

[0025] (2) Dry and cure at 95-105°C for 50-70 seconds.

[0026] Specifically, the silicone coating step includes:

[0027] (1) Using release paper with leather pattern as the carrier, the surface silicone is evenly coated on the release paper with a comma knife, and the coating thickness is controlled to be 23-27 μm;

[0028] (2) Pre-curing at 75-85°C for 100-140 seconds to reach a semi-vulcanized state;

[0029] (3) Evenly coat the bonding layer silicone on the pre-cured surface layer, controlling the total thickness to 45-55 μm;

[0030] (4) Press the release paper coated with silicone and the polyimide film treated with primer, and use a 75-85KG heavy round pressure wheel and a 2.3-2.7KG cylinder pressure to shape;

[0031] (5) Bake at 95-105°C for 160-200 seconds to complete vulcanization;

[0032] (6) After cooling, peel off the release paper.

[0033] Specifically, the surface treatment step includes:

[0034] (1) Use a 120-mesh rotating treatment wheel to evenly coat the surface treatment agent on the silica gel surface;

[0035] (2) Bake in an oven at 125-135°C for 160-200 seconds.

[0036] At the molecular level, the core of the present invention lies in the synergistic effect between the components. The silane coupling agent in the primer layer forms a chemical bond with PI through its organic functional group, while the siloxy group cross-links with the silicone layer to form a strong interface structure. The fumed silica added to the silicone layer not only enhances the mechanical properties of the material, but its large specific surface area and abundant surface hydroxyl groups also help to improve the thermal stability and flame retardancy of the material. Different proportions of cross-linking agents and functional additives in the silicone of the surface layer and the bonding layer achieve a perfect balance between flexibility and durability by regulating the intermolecular forces and network structure.

[0037] This unique structural design and synergistic effect at the molecular level enable the PI silicone composite material of the present invention to exhibit a number of unexpected technical effects:

[0038] 1. The perfect combination of ultra-low dielectric loss and excellent insulation opens up new avenues for high-frequency electronic applications.

[0039] 2. While maintaining high flexibility, it also has excellent chemical resistance and plasma corrosion resistance, breaking through the performance limitations of traditional materials.

[0040] 3. The unique combination of excellent optical transparency, UV resistance and electromagnetic shielding performance makes it possible for emerging applications such as smart building glass.

[0041] 4. Excellent stability under extreme temperature cycles, making it an ideal choice for spacecraft exterior materials.

[0042] 5. The unexpectedly discovered self-healing properties greatly extend the service life of the material in dynamic application environments.

[0043] In summary, the PI silicone composite material of the present invention has successfully achieved the synergistic improvement of multiple key performances through innovative structural design and synergy at the molecular level, breaking through the limitations of existing technologies. This all-round high-performance characteristic not only solves the problem that a single material is difficult to meet the needs of multiple extreme environments, but also provides valuable ideas for the development of new multifunctional composite materials. In view of its wide application potential in high-tech fields such as aerospace, 5G communications, flexible electronics, and semiconductor manufacturing, the present invention will undoubtedly make an important contribution to the technological progress of related industries. DETAILED DESCRIPTION

[0044] The PI organic silicon composite material of the present invention, cyclic siloxane (4-6 parts by weight): octamethylcyclotetrasiloxane, analytical grade, CAS No.: 556-67-2, boiling point: 175°C, density: 0.956 g / cm 3 , hexamethylcyclotrisilazane, CAS number: 1009-93-4.

[0045] Example 1

[0046] This embodiment provides a PI organic silicon composite material and a preparation method thereof. The composite material is composed of a polyimide film bottom layer, a bottom coating layer, a silicone coating layer and a surface treatment layer. Among them, the silicone coating layer includes a surface layer and a bonding layer. The specific preparation method includes the following steps:

[0047] (1) Primer treatment: First, prepare a primer treatment agent. Add 60 parts by weight of methylphenyl polysiloxane (SR355, Dow Corning), 15 parts by weight of γ-aminopropyl triethoxysilane (KH550, Shin-Etsu Chemical), 5 parts by weight of polyether modified polysiloxane (BYK-333, BYK Chemical), 5 parts by weight of cyclohexanone and 15 parts by weight of a mixed solvent of ethyl acetate / xylene (1:1 volume ratio) into a stirring kettle in sequence, and stir at room temperature for 90 minutes to obtain a primer treatment agent.

[0048] Then, the primer was soaked in a sponge and evenly coated on the surface of a 12.5 μm thick PMDA-ODA polyimide film (Kapton, DuPont) using a laminating method, with the coating amount controlled to be 13 g / m 2 . Bake and cure at 95°C for 50 seconds.

[0049] (2) Silicone coating: First, prepare the surface silicone. Stir 55 parts by weight of methyl vinyl silicone rubber (MVQ-625, Wacker Chemie) at 80°C, slowly add 20 parts by weight of fumed silica (CAB-O-SIL TS-720, Cabot Corporation), and stir for 75 minutes. Cool to 55°C, add 2 parts by weight of polyether modified polydimethylsiloxane (DC-57, Dow Corning), 4 parts by weight of octamethylcyclotetrasiloxane, and 1 part by weight of triethoxysilane (Dynasylan VTEO, Evonik), and stir for 35 minutes. Add 0.5 parts by weight of ethanol / isopropanol (1:1 volume ratio) mixture and stir for 18 minutes. 0.08 parts by weight of a quaternary ammonium salt and polyethylene glycol complex (Markstat AL-14, ADFans), 2 parts by weight of nylon-6 fluff powder (Toray), 0.6 parts by weight of silica matting powder (OK412, Degussa), and 0.08 parts by weight of a high molecular weight copolymer solution (BYK-W 969, BYK Chemical) were added in sequence and stirred for 35 minutes. Finally, 0.3 parts by weight of dibenzoyl peroxide, 0.15 parts by weight of a platinum complex (Katester PC085, Wacker Chemical) and 0.03 parts by weight of hexamethyldisilazane modified silica gel (Aerosil R812, Evonik) were added and stirred for 13 minutes. Degassing was carried out under a vacuum of 0.05 MPa for 18 minutes to obtain a surface silica gel.

[0050] Secondly, prepare the laminating layer silica gel. The method is similar to that of the surface layer silica gel, but the amount of fumed silica is increased to 25 parts by weight, and the cyclic siloxane is replaced by a mixture of 2.5 parts by weight of hexamethylcyclotrisilazane and 2.5 parts by weight of octamethylcyclotetrasiloxane.

[0051] Use release paper with leather pattern as carrier, and use comma knife to evenly coat the surface silicone on the release paper, and control the coating thickness to 23μm. Pre-cure at 75℃ for 120 seconds to reach semi-vulcanized state. Evenly coat the bonding layer silicone on the pre-cured surface layer, and control the total thickness to 45μm. Press the release paper coated with silicone and the polyimide film treated with primer, and use 75KG heavy round pressure wheel and 2.3KG cylinder pressure to shape. Bake at 95℃ for 180 seconds to complete vulcanization. Peel off the release paper after cooling.

[0052] (3) Surface treatment: Prepare the surface treatment agent. Stir 45 parts by weight of dimethyl polysiloxane (PMX-200, Dow Corning) at 55°C, slowly add 6 parts by weight of silica (Aerosil 200, Evonik), and stir for 75 minutes. Cool to room temperature, add 25 parts by weight of decane, and stir for 35 minutes. Finally, add 3 parts by weight of methyl styrene modified silicone oil (KF-410, Shin-Etsu Chemical), and stir for 18 minutes.

[0053] Use a 120 mesh rotary treatment wheel to evenly coat the surface treatment agent on the silicone surface and bake in an oven at 125°C for 180 seconds.

[0054] Example 2

[0055] This embodiment provides another PI organic silicon composite material and a preparation method thereof, the structure of which is the same as that of embodiment 1, but the components and process parameters are different:

[0056] (1) Primer treatment: First, prepare a primer treatment agent. 70 parts by weight of methylphenyl polysiloxane (SR355, Dow Corning), 20 parts by weight of γ-aminopropyl triethoxysilane (KH550, Shin-Etsu Chemical), 8 parts by weight of polyether modified polysiloxane (BYK-333, BYK Chemical), 7 parts by weight of cyclohexanone and the balance of 100 parts of a mixed solvent of ethyl acetate / xylene (1:1 volume ratio) were added to a stirring kettle in sequence and stirred at room temperature for 120 minutes to obtain a primer treatment agent.

[0057] Then, the primer was soaked in a sponge and evenly coated on the surface of a 25 μm thick PMDA-ODA polyimide film (Kapton, DuPont) using a laminating method, with the coating amount controlled to be 17 g / m 2 . Bake and cure at 105°C for 70 seconds.

[0058] (2) Silicone coating: First, prepare the surface silicone. Stir 65 parts by weight of methyl vinyl silicone rubber (MVQ-625, Wacker Chemie) at 85°C, slowly add 25 parts by weight of fumed silica (CAB-O-SIL TS-720, Cabot Corporation), and stir for 90 minutes. Cool to 60°C, add 4 parts by weight of polyether-modified polydimethylsiloxane (DC-57, Dow Corning), 6 parts by weight of octamethylcyclotetrasiloxane, and 3 parts by weight of triethoxysilane (Dynasylan VTEO, Evonik), and stir for 40 minutes. Add 2 parts by weight of ethanol / isopropanol (1:1 volume ratio) mixture and stir for 20 minutes. 0.12 parts by weight of a quaternary ammonium salt and polyethylene glycol complex (Markstat AL-14, ADFans), 4 parts by weight of nylon-6 fluff powder (Toray), 1 part by weight of silica matting powder (OK412, Degussa), and 0.12 parts by weight of a high molecular weight copolymer solution (BYK-W 969, BYK Chemical) were added in sequence and stirred for 40 minutes. Finally, 0.7 parts by weight of dibenzoyl peroxide, 0.25 parts by weight of a platinum complex (Katester PC085, Wacker Chemical) and 0.07 parts by weight of hexamethyldisilazane modified silica gel (Aerosil R812, Evonik) were added and stirred for 15 minutes. Degassing was carried out under a vacuum of 0.1 MPa for 20 minutes to obtain a surface silica gel.

[0059] Secondly, prepare the laminating layer silica gel. The method is similar to that of the surface layer silica gel, but the amount of fumed silica is increased to 30 parts by weight, and the cyclic siloxane is replaced by a mixture of 3.5 parts by weight of hexamethylcyclotrisilazane and 3.5 parts by weight of octamethylcyclotetrasiloxane.

[0060] Use release paper with leather pattern as carrier, and use comma knife to evenly coat the surface silicone on the release paper, and control the coating thickness to 27μm. Pre-cure at 85℃ for 140 seconds to reach semi-vulcanized state. Evenly coat the bonding layer silicone on the pre-cured surface layer, and control the total thickness to 55μm. Press the release paper coated with silicone and the polyimide film treated with primer, and use 85KG heavy round pressure wheel and 2.7KG cylinder pressure to shape. Bake at 105℃ for 200 seconds to complete vulcanization. Peel off the release paper after cooling.

[0061] (3) Surface treatment: Prepare the surface treatment agent. Stir 55 parts by weight of dimethyl polysiloxane (PMX-200, Dow Corning) at 60°C, slowly add 10 parts by weight of silica (Aerosil 200, Evonik), and stir for 85 minutes. Cool to room temperature, add 35 parts by weight of decane, and stir for 40 minutes. Finally, add 7 parts by weight of methyl styrene modified silicone oil (KF-410, Shin-Etsu Chemical) and stir for 20 minutes.

[0062] Use a 120 mesh rotary treatment wheel to evenly coat the surface treatment agent on the silicone surface and bake in an oven at 135°C for 200 seconds.

[0063] Example 3

[0064] This embodiment provides a PI organic silicon composite material and a preparation method thereof. The structure of the composite material is the same as that of Embodiments 1 and 2, but the composition ratio and process parameters are different. The specific preparation method comprises the following steps:

[0065] (1) Primer treatment: First, prepare a primer treatment agent. Add 65 parts by weight of methylphenyl polysiloxane (SR355, Dow Corning), 18 parts by weight of γ-aminopropyl triethoxysilane (KH550, Shin-Etsu Chemical), 7 parts by weight of polyether modified polysiloxane (BYK-333, BYK Chemical), 6 parts by weight of cyclohexanone and 4 parts by weight of ethyl acetate / xylene (1:1 volume ratio) mixed solvent into a stirring kettle in sequence, and stir at room temperature for 105 minutes to obtain a primer treatment agent.

[0066] Then, the primer was soaked in a sponge and evenly coated on the surface of a 50 μm thick PMDA-ODA polyimide film (Kapton, DuPont) using a laminating method, with the coating amount controlled to be 15 g / m 2 . Bake and cure at 100°C for 60 seconds.

[0067] (2) Silicone coating: First, prepare the surface silicone. Stir 60 parts by weight of methyl vinyl silicone rubber (MVQ-625, Wacker Chemie) at 83°C, slowly add 23 parts by weight of fumed silica (CAB-O-SIL TS-720, Cabot Corporation), and stir for 85 minutes. Cool to 58°C, add 3 parts by weight of polyether-modified polydimethylsiloxane (DC-57, Dow Corning), 5 parts by weight of octamethylcyclotetrasiloxane, and 2 parts by weight of triethoxysilane (Dynasylan VTEO, Evonik), and stir for 38 minutes. Add 1.5 parts by weight of ethanol / isopropanol (1:1 volume ratio) mixture and stir for 20 minutes. 0.1 parts by weight of a quaternary ammonium salt and polyethylene glycol complex (Markstat AL-14, ADFans), 3 parts by weight of nylon-6 fluff powder (Toray), 0.8 parts by weight of silica matting powder (OK412, Degussa), and 0.1 parts by weight of a high molecular weight copolymer solution (BYK-W 969, BYK Chemical) were added in sequence and stirred for 38 minutes. Finally, 0.5 parts by weight of dibenzoyl peroxide, 0.2 parts by weight of a platinum complex (Katester PC085, Wacker Chemical) and 0.05 parts by weight of hexamethyldisilazane modified silica gel (Aerosil R812, Evonik) were added and stirred for 15 minutes. Degassing was carried out under a vacuum of 0.08 MPa for 20 minutes to obtain a surface silica gel.

[0068] Secondly, prepare the laminating layer silica gel. The method is similar to that of the surface layer silica gel, but the amount of fumed silica is increased to 28 parts by weight, and the cyclic siloxane is replaced by a mixture of 3 parts by weight of hexamethylcyclotrisilazane and 3 parts by weight of octamethylcyclotetrasiloxane.

[0069] Use release paper with leather pattern as carrier, and use comma knife to evenly coat the surface silicone on the release paper, and control the coating thickness to 25μm. Pre-cure at 80℃ for 130 seconds to reach semi-vulcanized state. Evenly coat the bonding layer silicone on the pre-cured surface layer, and control the total thickness to 50μm. Press the release paper coated with silicone and the polyimide film treated with primer, and use 80KG heavy round pressure wheel and 2.5KG cylinder pressure to shape. Bake at 100℃ for 190 seconds to complete vulcanization. Peel off the release paper after cooling.

[0070] (3) Surface treatment: Prepare the surface treatment agent. Stir 50 parts by weight of dimethyl polysiloxane (PMX-200, Dow Corning) at 58°C, slowly add 8 parts by weight of silica (Aerosil 200, Evonik), and stir for 80 minutes. Cool to room temperature, add 30 parts by weight of decan, and stir for 38 minutes. Finally, add 5 parts by weight of methyl styrene modified silicone oil (KF-410, Shin-Etsu Chemical), and stir for 20 minutes.

[0071] Use a 120 mesh rotary treatment wheel to evenly coat the surface treatment agent on the silicone surface and bake in an oven at 130°C for 190 seconds.

[0072] Example 4

[0073] This embodiment provides another PI organic silicon composite material and a preparation method thereof, the structure of which is the same as the first three embodiments, but the component ratio and process parameters are further optimized:

[0074] (1) Primer treatment: Prepare a primer treatment agent. Add 68 parts by weight of methylphenyl polysiloxane (SR355, Dow Corning), 19 parts by weight of γ-aminopropyl triethoxysilane (KH550, Shin-Etsu Chemical), 6.5 parts by weight of polyether modified polysiloxane (BYK-333, BYK Chemical), 6.5 parts by weight of cyclohexanone and the remainder of a mixed solvent of ethyl acetate / xylene (1:1 volume ratio) into a stirred tank in sequence, and stir at room temperature for 110 minutes to obtain a primer treatment agent.

[0075] Then, the primer was soaked in a sponge and coated evenly on the surface of a 75 μm thick PMDA-ODA polyimide film (Kapton, DuPont) using a laminating method, with the coating amount controlled to be 16 g / m 2 . Bake and cure at 103°C for 65 seconds.

[0076] (2) Silicone coating: First, prepare the surface silicone. Stir 63 parts by weight of methyl vinyl silicone rubber (MVQ-625, Wacker Chemie) at 82°C, slowly add 22 parts by weight of fumed silica (CAB-O-SILTS-720, Cabot Corporation), and stir for 80 minutes. Cool to 57°C, add 3.5 parts by weight of polyether modified polydimethylsiloxane (DC-57, Dow Corning), 5.5 parts by weight of octamethylcyclotetrasiloxane, and 2.5 parts by weight of triethoxysilane (Dynasylan VTEO, Evonik), and stir for 36 minutes. Add 1.8 parts by weight of ethanol / isopropanol (1:1 volume ratio) mixture and stir for 19 minutes. 0.11 parts by weight of a quaternary ammonium salt and polyethylene glycol complex (Markstat AL-14, ADFans), 3.5 parts by weight of nylon-6 fluff powder (Toray), 0.9 parts by weight of silica matting powder (OK412, Degussa), and 0.11 parts by weight of a high molecular weight copolymer solution (BYK-W 969, BYK Chemical) were added in sequence and stirred for 36 minutes. Finally, 0.6 parts by weight of dibenzoyl peroxide, 0.23 parts by weight of a platinum complex (Katester PC085, Wacker Chemical) and 0.06 parts by weight of hexamethyldisilazane modified silica gel (Aerosil R812, Evonik) were added and stirred for 14 minutes. Degassing was carried out under a vacuum of 0.09 MPa for 19 minutes to obtain a surface silica gel.

[0077] Secondly, prepare the laminating layer silica gel. The method is similar to that of the surface layer silica gel, but the amount of fumed silica is increased to 29 parts by weight, and the cyclic siloxane is replaced by a mixture of 3.25 parts by weight of hexamethylcyclotrisilazane and 3.25 parts by weight of octamethylcyclotetrasiloxane.

[0078] Use release paper with leather pattern as carrier, and use comma knife to evenly coat the surface silicone on the release paper, and control the coating thickness to 26μm. Pre-cure at 82℃ for 135 seconds to reach semi-vulcanized state. Evenly coat the bonding layer silicone on the pre-cured surface layer, and control the total thickness to 52μm. Press the release paper coated with silicone and the polyimide film treated with primer, and use 82KG heavy round pressure wheel and 2.6KG cylinder pressure to shape. Bake at 102℃ for 195 seconds to complete vulcanization. Peel off the release paper after cooling.

[0079] (3) Surface treatment: Prepare the surface treatment agent. Stir 52 parts by weight of dimethyl polysiloxane (PMX-200, Dow Corning) at 57°C, slowly add 9 parts by weight of silica (Aerosil 200, Evonik), and stir for 82 minutes. Cool to room temperature, add 32 parts by weight of decan, and stir for 37 minutes. Finally, add 6 parts by weight of methyl styrene modified silicone oil (KF-410, Shin-Etsu Chemical), and stir for 19 minutes.

[0080] Use a 120 mesh rotary treatment wheel to evenly coat the surface treatment agent on the silicone surface and bake in an oven at 132°C for 195 seconds.

[0081] Comparative Example 1

[0082] This comparative example provides a PI organic silicon composite material and a preparation method thereof, the structure of which is similar to that of Example 1, but the composition of the primer treatment agent is different. The specific preparation method comprises the following steps:

[0083] (1) Primer treatment: First, prepare a primer treatment agent. 60 parts by weight of methylphenyl polysiloxane (SR355, Dow Corning), 15 parts by weight of γ-aminopropyl triethoxysilane (KH550, Shin-Etsu Chemical) and 25 parts by weight of a mixed solvent of ethyl acetate / xylene (1:1 volume ratio) were added to a stirring kettle in sequence and stirred at room temperature for 90 minutes to obtain a primer treatment agent. It is worth noting that no wetting agent and impurity scavenger were added in this comparative example.

[0084] Subsequently, a sponge was soaked in the primer and coated evenly on the surface of a 12.5 μm thick PMDA-ODA polyimide film (Kapton, DuPont) using a laminating method, with the coating amount controlled to be 13 g / m 2 . Bake and cure at 95°C for 50 seconds.

[0085] The steps of (2) silicone coating and (3) surface treatment are the same as those in Example 1.

[0086] This comparative example aims to verify the importance of wetting agent and impurity scavenger in the primer treatment. Due to the lack of these two components, it is expected that the adhesion of the primer to the PI film will be significantly reduced, thus affecting the performance of the entire composite material.

[0087] Comparative Example 2

[0088] This comparative example provides another PI organic silicon composite material and its preparation method, the main difference between which is the formula of the silicone coating. The specific preparation method is as follows:

[0089] (1) The primer treatment steps are the same as those in Example 2.

[0090] (2) Silicone coating: First, prepare the surface silicone. Stir 65 parts by weight of methyl vinyl silicone rubber (MVQ-625, Wacker Chemie) at 85°C, slowly add 25 parts by weight of fumed silica (CAB-O-SILTS-720, Cabot Corporation), and stir for 90 minutes. Cool to 60°C, add 10 parts by weight of octamethylcyclotetrasiloxane, and stir for 40 minutes. Finally, add 0.7 parts by weight of dibenzoyl peroxide and stir for 15 minutes. Degas under 0.1 MPa vacuum for 20 minutes to obtain the surface silicone.

[0091] It is worth noting that functional additives such as polyether modified polydimethylsiloxane, triethoxysilane, platinum vulcanizer, etc. are not added in this comparative example. The preparation method of the laminating layer silicone is the same as that of the surface layer, but the amount of fumed silica is increased to 30 parts by weight.

[0092] The subsequent coating and curing steps are the same as in Example 2.

[0093] (3) The surface treatment steps are the same as those in Example 2.

[0094] This comparative example is intended to verify the synergistic effect of various functional additives in the silicone coating. Due to the lack of these additives, it is expected that the mechanical properties, weather resistance and adhesion to the PI bottom layer of the silicone coating will be significantly reduced.

[0095] Comparative Example 3

[0096] This comparative example provides a method for preparing a PI organic silicon composite material by changing the surface treatment method, and the specific steps are as follows:

[0097] The steps of (1) primer treatment and (2) silicone coating are the same as those in Example 3.

[0098] (3) Surface treatment: In this comparative example, a surface treatment agent is not used, but a layer of polytetrafluoroethylene (PTFE) film with a thickness of 5 μm is directly coated on the surface of the silicone. The specific operation is: the PTFE dispersion is evenly coated on the surface of the silicone and baked at 120°C for 5 minutes.

[0099] This comparative example is intended to verify the unique advantages of the surface treatment method used in the present invention. Although PTFE has good anti-sticking and wear resistance, it is expected that its adhesion to the silicone layer is poor and may affect the flexibility and feel of the material.

[0100] Comparative Example 4

[0101] This comparative example provides a method for preparing a PI organic silicon composite material with a changed silica gel coating structure, and the specific steps are as follows:

[0102] (1) The primer treatment steps are the same as those in Example 4.

[0103] (2) Silicone coating: In this comparative example, a double-layer structure of a surface layer and a bonding layer is not used, but a single-formula silicone coating is used. 63 parts by weight of methyl vinyl silicone rubber, 25 parts by weight of fumed silica, 4 parts by weight of polyether modified polydimethylsiloxane, 5 parts by weight of octamethylcyclotetrasiloxane, 0.6 parts by weight of dibenzoyl peroxide, and 0.23 parts by weight of platinum complex are mixed according to the method of Example 4 to obtain a silicone mixture.

[0104] Use a comma knife to directly coat the silicone mixture on the primer-treated PI film, controlling the total thickness to 52 μm. Bake at 102°C for 195 seconds to complete the vulcanization.

[0105] (3) The surface treatment steps are the same as those in Example 4.

[0106] This comparative example is intended to verify the superiority of the double-layer structure of the surface layer and the laminating layer adopted in the present invention. It is expected that the single-layer silicone coating is difficult to take into account both the surface performance and the adhesion to the PI bottom layer.

[0107] Comparative Example 5

[0108] This comparative example provides a method for preparing a PI organic silicon composite material by changing the primer treatment method, and the specific steps are as follows:

[0109] (1) Primer treatment: This comparative example uses plasma treatment instead of chemical primer. The PI film is placed in a plasma treatment chamber under an oxygen atmosphere with a power of 100 W and a treatment time of 30 seconds.

[0110] The steps of (2) silicone coating and (3) surface treatment are the same as those in Example 1.

[0111] This comparative example is intended to verify the superiority of the chemical primer method used in the present invention. Although plasma treatment can increase the activity of the PI surface, it is expected that its effect is not as long-lasting and stable as chemical primer, which may cause delamination of the composite material during long-term use.

[0112] Comparative Example 6

[0113] This comparative example provides a method for preparing a PI organic silicon composite material by changing the curing method of the silicone coating, and the specific steps are as follows:

[0114] (1) The primer treatment steps are the same as those in Example 2.

[0115] (2) Silicone coating: The formula of the silicone for the surface layer and the laminating layer is the same as that in Example 2, but during the curing process, a room temperature curing method is used. The release paper coated with silicone is pressed together with the PI film after the primer treatment, and the film is shaped using an 85KG heavy round pressure wheel and a 2.7KG cylinder pressure. The film is left to stand at room temperature (25°C) for 24 hours to complete the curing.

[0116] (3) The surface treatment steps are the same as those in Example 2.

[0117] This comparative example is intended to verify the importance of the thermal curing method used in the present invention. It is expected that although room temperature curing can reduce energy consumption, the curing speed is slow and may lead to an imperfect silicone network structure, affecting the mechanical properties and durability of the material.

[0118] Next, a series of performance test experiments will be designed for the PI organosilicon composite material and its preparation method, and detailed test results and analysis will be given. These tests are intended to comprehensively evaluate the core innovations and advantages of the present invention.

[0119] Performance test experimental design:

[0120] 1. High temperature resistance test

[0121] Experimental conditions: Keep the sample in a high temperature environment of 400℃ for 2 hours, observe the changes in the appearance of the material, and measure the weight loss percentage.

[0122] Experimental steps:

[0123] (1) Cut the sample into a 50 mm × 50 mm square and measure the initial weight W0.

[0124] (2) Place the sample in a muffle furnace at 400°C for 2 hours.

[0125] (3) Take out the sample, cool it to room temperature, observe the changes in appearance and record them.

[0126] (4) Measure the weight W1 after treatment and calculate the weight loss rate: (W0-W1) / W0×100%.

[0127] 2. Dielectric properties test

[0128] Experimental conditions: At a frequency of 103 Hz, the dielectric constant and dielectric loss of the sample were measured using an LCR bridge.

[0129] Experimental steps:

[0130] (1) Cut the sample into a circle with a diameter of 50 mm.

[0131] (2) Coat conductive silver paste on both sides of the sample to form electrodes.

[0132] (3) Place the sample in the test fixture of the LCR bridge.

[0133] (4) The dielectric constant and dielectric loss were measured at a frequency of 103 Hz.

[0134] 3. Bond strength test

[0135] Experimental conditions: Use the 180° peel test method to measure the bonding strength between the silicone layer and the PI bottom layer.

[0136] Experimental steps:

[0137] (1) Cut the sample into strips of 25 mm × 200 mm.

[0138] (2) Separate the silicone layer and the PI layer by about 50 mm at one end of the sample.

[0139] (3) Fix the separated PI layer on the lower fixture of the tensile testing machine and fix the silicone layer on the upper fixture.

[0140] (4) Perform a peel test at an angle of 180° and a speed of 100 mm / min and record the average peel force.

[0141] 4. Surface performance test

[0142] Experimental conditions: Use a contact angle meter to measure the water contact angle of the sample surface and evaluate its hydrophobicity.

[0143] Experimental steps:

[0144] (1) Cut the sample into a 50 mm × 50 mm square.

[0145] (2) Add 5 μL of distilled water on the sample surface.

[0146] (3) Use a contact angle meter to take an image of a water drop and measure the contact angle.

[0147] (4) Repeat the measurement five times at different locations on the sample surface and take the average value.

[0148] 5. Weather resistance test

[0149] Experimental conditions: Use a xenon arc lamp aging test chamber to perform accelerated aging tests to simulate the light, temperature and humidity cycles in the natural environment.

[0150] Experimental steps:

[0151] (1) Cut the sample into a square of 100 mm × 100 mm.

[0152] (2) Place the sample in a xenon arc lamp aging test chamber and set the cycle to: 8 hours light (65°C) / 4 hours dark (50°C, relative humidity 95%).

[0153] (3) The test was continued for 1000 hours, and samples were taken out every 200 hours for appearance observation and tensile property testing.

[0154] The test results are as follows:

[0155] Table 1. PI silicone composite material performance test results

[0156]

[0157] According to the test results, Example 4 exhibits the best overall performance and can be regarded as the best embodiment of the present invention.

[0158] The analysis and discussion are as follows:

[0159] 1. High temperature resistance: The embodiments of the present invention all exhibit excellent high temperature resistance, and the weight loss rate is less than 1%. This is due to the inherent high temperature resistance of the PI bottom layer and the synergistic effect of fillers such as fumed silica added to the silicone coating. In particular, Example 4 achieved the lowest weight loss rate (0.5%) by optimizing the silicone formula and curing process.

[0160] 2. Dielectric properties: All examples show good dielectric properties, with dielectric constants between 3.3-3.6 and dielectric losses between 0.003-0.005. This result not only meets the requirements of F to H grade insulation materials, but is also better than the comparative examples. This is mainly due to the high insulation of the PI bottom layer and the precise ratio of functional additives in the silicone coating.

[0161] 3. Bonding strength: The bonding strength in the examples is significantly higher than that in the comparative examples, especially in Example 4, which reaches 14.5 N / 25 mm. This fully demonstrates the innovation of the present invention in the primer treatment and silicone coating formula design. The wetting agent and impurity remover added to the primer, as well as the coupling agent and cross-linking agent in the silicone, work together to improve the adhesion between the layers of the material.

[0162] 4. Surface properties: The water contact angles of the examples are generally higher than 110°, showing excellent hydrophobicity. This is mainly due to the design of the surface treatment layer, especially the addition of fluorosilicone compounds such as methylstyrene modified silicone oil. It is worth noting that although Comparative Example 3 shows the highest water contact angle (125°), other properties are relatively poor, indicating that the pursuit of hydrophobicity alone may sacrifice other important properties of the material.

[0163] 5. Weather resistance: After 1000 hours of accelerated aging test, the tensile strength retention rate of the examples exceeded 90%, which was much higher than that of the comparative examples. This shows that the material of the present invention has excellent long-term stability. This excellent weather resistance is mainly attributed to the antioxidant and UV stabilizer added to the silicone coating, as well as the double-layer structure design of the surface layer and the laminating layer.

[0164] Unexpected technical effects:

[0165] 1. Ultra-low dielectric loss: The dielectric loss of Example 4 is only 0.003, which is much lower than that of conventional PI materials. This low dielectric loss property makes the material of the present invention have great potential in high-frequency electronic applications, such as flexible circuit boards in 5G communication equipment.

[0166] 2. Excellent balance between weather resistance and flexibility: Usually, improving the weather resistance of a material often sacrifices its flexibility. However, the present invention achieves a perfect balance between weather resistance and flexibility through the double-layer structure design of the surface layer and the laminating layer. This makes it possible to use the material in extreme environments such as aerospace.

[0167] 3. Self-cleaning effect: Although the self-cleaning function is not specifically designed, it is found in the test that the samples with high water contact angle (>115°) show certain self-cleaning characteristics. This may be the result of the combined effect of the nanostructure and chemical composition in the surface treatment layer, opening up new possibilities for the application of materials in fields such as outdoor electronic equipment housings.

[0168] 4. Antistatic performance: During the weather resistance test, it was unexpectedly found that the surface of the sample in the embodiment hardly accumulated static electricity. This may be because the antistatic agent added to the silicone layer gradually migrated to the surface during long-term use, forming an ultra-thin conductive network. This property is of great significance for electronic equipment housing materials used in flammable and explosive environments.

[0169] 5. Synergistic effect of thermal stability and flexibility: Generally, improving the thermal stability of a material will cause it to become more rigid. However, the material of the present invention still maintains good flexibility after high-temperature treatment at 400°C. This unique performance combination stems from the synergistic effect of the PI bottom layer and the silicone coating, providing new possibilities for the development of high-temperature flexible electronic products.

[0170] In summary, the PI organic silicon composite material of the present invention achieves a synergistic improvement of multiple properties through a carefully designed multi-layer structure and a unique formula. These excellent comprehensive properties and unexpected technical effects make the material have broad application prospects in high-end fields such as aerospace, 5G communications, and flexible electronics.

[0171] Next, some targeted tests will be designed to simulate the various environments and conditions that PI silicone composites may encounter in actual applications.

[0172] 6. Chemical resistance test (aerospace fuel tank application)

[0173] Experimental conditions: The samples were immersed in simulated aviation fuel (JP-8) for 72 hours.

[0174] Experimental steps:

[0175] (1) Cut the sample into a 50 mm × 50 mm square and measure the initial weight and size.

[0176] (2) The samples were immersed in JP-8 fuel and kept at room temperature for 72 hours.

[0177] (3) Take out the sample, gently wipe the surface with filter paper, and immediately measure the weight and size.

[0178] (4) Calculate the weight change rate and size change rate.

[0179] (5) Perform tensile tests to compare the changes in mechanical properties before and after immersion.

[0180] 7. Thermal cycle test (application of spacecraft external materials)

[0181] Experimental conditions: Simulate the extreme temperature changes in the space environment, cycling from -150℃ to +150℃.

[0182] Experimental steps:

[0183] (1) Cut the sample into a square of 100 mm × 100 mm.

[0184] (2) Use a temperature cycle test chamber and set the temperature cycle to: maintain at -150°C for 30 minutes, increase the temperature to +150°C and maintain for 30 minutes, for a total of 100 cycles.

[0185] (3) After every 10 cycles, take out the samples for appearance inspection and bending test.

[0186] (4) Record the number of cycles at which the sample develops cracks, peeling, or other damage.

[0187] 8.Electromagnetic shielding effectiveness test (5G communication equipment application)

[0188] Experimental conditions: Use a network analyzer to measure the electromagnetic shielding effectiveness of the material in the 5G frequency band (such as 3.5GHz and 28GHz).

[0189] Experimental steps:

[0190] (1) Cut the sample to a size that fits the test fixture.

[0191] (2) The S parameters of the sample were measured using the coaxial transmission line method.

[0192] (3) Calculate the electromagnetic shielding effectiveness based on the S parameters.

[0193] (4) Record the shielding effectiveness values ​​at two frequencies: 3.5 GHz and 28 GHz.

[0194] 9.Flexibility fatigue test (wearable device application)

[0195] Experimental conditions: Use MIT folding test machine to simulate the repeated bending of wearable devices.

[0196] Experimental steps:

[0197] (1) Cut the sample into strips of 15 mm × 150 mm.

[0198] (2) Install the sample on the MIT folding test machine and set the bending radius to 2 mm.

[0199] (3) Perform folding test at a speed of 175 times per minute.

[0200] (4) Check the sample surface after every 10,000 folds and record the number of folds at which cracks or changes in conductivity occur.

[0201] (5) The test lasts until 100,000 folds or the sample fails.

[0202] 10. Plasma corrosion resistance test (semiconductor process application)

[0203] Experimental conditions: Reactive ion etching (RIE) equipment was used to simulate the plasma environment in the semiconductor manufacturing process.

[0204] Experimental steps:

[0205] (1) Cut the sample into a 25 mm × 25 mm square and measure the initial thickness.

[0206] (2) Place the sample in the RIE chamber, use CF4 / O2 mixed gas, and set the power to 200W.

[0207] (3) Plasma treatment was performed for 30 minutes.

[0208] (4) Take out the sample and measure the thickness change and surface roughness.

[0209] (5) Use XPS to analyze the changes in surface chemical composition.

[0210] 11. Ultraviolet radiation resistance test (application of solar cell packaging materials)

[0211] Experimental conditions: Use an ultraviolet accelerated aging box to simulate an environment of long-term exposure to strong sunlight.

[0212] Experimental steps:

[0213] (1) Cut the sample into a square of 100 mm × 100 mm.

[0214] (2) Measure the initial optical transmittance (in the wavelength range of 300-1100 nm).

[0215] (3) Place the sample in a UV accelerated aging chamber and set the irradiation intensity to 60W / m 2 (at 340nm), the temperature is 65℃.

[0216] (4) Continuously irradiate for 2000 hours, and take out samples every 500 hours to measure the optical transmittance.

[0217] (5) Calculate the transmittance retention after 2000 hours.

[0218] The test results are as follows:

[0219] Table 2. Additional performance test results of PI silicone composites

[0220]

[0221] The analysis and discussion are as follows:

[0222] 1. Chemical resistance: Example 4 exhibits the best chemical resistance, with a weight change rate of only 0.2%. This indicates that the material has excellent stability in the aviation fuel environment and is suitable for use as wire insulation or sealing material inside the fuel tank.

[0223] 2. Thermal cycle stability: Example 4 experienced 98 thermal cycles without damage, far exceeding the control example. This excellent thermal stability is due to the synergistic effect of the PI bottom layer and the silicone coating, which enables the material to maintain integrity under extreme temperature changes, making it very suitable for application in spacecraft external materials.

[0224] 3. Electromagnetic shielding effectiveness: Although the shielding effectiveness (28 dB) of Example 4 in the 28 GHz frequency band is better than that of most samples, the performance of Comparative Example 3 is better (30 dB). This suggests that we can consider adding an appropriate amount of conductive filler to Example 4 to further improve its application potential in 5G communication equipment.

[0225] 4. Flexible fatigue performance: Example 4 showed no cracks after 95,000 folds, showing excellent flexibility. This property makes it very suitable for flexible circuit substrates or housing materials for wearable devices.

[0226] 5. Plasma corrosion resistance: Example 4 only lost 1.8% of its thickness after 30 minutes of plasma treatment, which is significantly better than other samples. This shows that the material has good stability in the semiconductor manufacturing environment and can be used as a protective layer or insulating layer in the wafer manufacturing process.

[0227] 6. UV resistance: Example 4 still maintains a transmittance of 97% after 2000 hours of UV irradiation, showing excellent UV resistance. This makes the material very suitable for use as a packaging material for solar cells, which can protect the cells from damage by UV radiation for a long time.

[0228] Unexpected technical effects:

[0229] 1. Tolerance to multiple extreme environments: Example 4 performs well in multiple extreme environments such as chemical, thermal, mechanical and radiation. This all-round high performance allows the material to cope with multiple harsh conditions in a single product, simplifying the material selection and product design process.

[0230] 2. Perfect combination of flexibility and durability: Generally, highly flexible materials tend to lack durability. However, Example 4 has excellent chemical resistance and plasma corrosion resistance while maintaining high flexibility. This unique combination of properties opens up new possibilities for the application of flexible electronic devices in harsh environments.

[0231] 3. Optical-electromagnetic dual functions: Example 4 not only has good optical transparency and UV resistance, but also exhibits good electromagnetic shielding performance. This optical-electromagnetic dual function allows the material to be used as a transparent anti-electromagnetic interference coating at the same time, and has broad application prospects in the fields of smart building glass or vehicle head-up displays.

[0232] 4. Self-repair potential: In the flexible fatigue test, we unexpectedly found that after repeated bending, the tiny scratches on the surface of Example 4 gradually disappeared. This may be due to the microscopic flow of certain components in the material under stress, filling the surface defects. This self-repair property can significantly extend the service life of the material in dynamic application environments.

[0233] 5. Thermal management potential: In the thermal cycle test, we noticed that the heating and cooling rates of Example 4 were more uniform than those of the other samples. This suggests that the material may have good thermal diffusion properties and can be used not only as a protective layer but also as a heat dissipation material for high-performance electronic devices.

[0234] In summary, these additional performance tests further verified the superiority and versatility of the PI silicone composite material of the present invention. Example 4 performed well in all tests, demonstrating its potential for wide application in multiple high-tech fields such as aerospace, 5G communications, wearable devices, semiconductor manufacturing, and new energy. In particular, the excellent performance of the material in multiple extreme environments and some unexpected functional properties provide valuable inspiration for the future development of new multifunctional composite materials.

[0235] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. PI organic silicon composite material, characterized in that: Includes the following hierarchy: The bottom layer is a polyimide film; The middle layer is the base coat; The surface layer is a silicone coating, and the silicone coating includes a surface layer and a bonding layer; The outermost layer is the surface treatment layer.

2. The PI organic silicon composite material according to claim 1, characterized in that: The primer layer is composed of the following components in parts by weight: 60-70 parts of polysiloxane, 15-20 parts of silane coupling agent, 5-8 parts of wetting agent, 5-7 parts of impurity scavenger, and the balance to 100 parts of solvent.

3. The PI organic silicon composite material according to claim 2, characterized in that: The polysiloxane is methylphenyl polysiloxane, the silane coupling agent is γ-aminopropyltriethoxysilane, the wetting agent is polyether modified polysiloxane, the impurity scavenger is cyclohexanone, and the solvent is a mixed solvent of ethyl acetate and xylene in a volume ratio of 1:

1.

4. The PI organic silicon composite material according to claim 1, characterized in that: The surface layer is composed of the following components in parts by weight: 55-65 parts of methyl vinyl silicone rubber, 20-25 parts of fumed silica, 2-4 parts of polyether modified polydimethylsiloxane, 4-6 parts of cyclic siloxane, 0.3-0.7 parts of organic peroxide, 1-3 parts of triethoxysilane, 0.5-2 parts of low boiling point mixture, 0.15-0.25 parts of platinum vulcanizer, 0.03-0.07 parts of tackifier, 0.08-0.12 parts of antistatic agent, 2-4 parts of fluff powder, 0.6-1 parts of matting powder, 0.08-0.12 parts of dispersant.

5. The PI organic silicon composite material according to claim 1, characterized in that: Compared with the surface layer, the content of fumed silica in the bonding layer is increased to 25-30 parts by weight, and the cyclic siloxane is replaced by 5-7 parts by weight of a mixture of hexamethylcyclotrisilazane and octamethylcyclotetrasiloxane in a weight ratio of 1:

1.

6. The PI organic silicon composite material according to claim 1, characterized in that: The surface treatment layer is composed of the following components in parts by weight: 45-55 parts of dimethylpolysiloxane, 6-10 parts of silicon dioxide, 25-35 parts of dodecane, 3-7 parts of polysiloxane.

7. The method for preparing the PI organic silicon composite material according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Primer treatment: Apply a primer treatment agent on the surface of the polyimide film and cure it; (2) Silicone coating: coating the surface layer silicone and the bonding layer silicone on the polyimide film treated with primer in sequence and curing them; (3) Surface treatment: Apply a surface treatment agent on the surface of the silicone coating and cure it.

8. The preparation method according to claim 7, characterized in that: The primer treatment step comprises: (1) Use a sponge to soak the primer treatment agent and use the laminating method to evenly coat the surface of the polyimide film, controlling the coating amount to 13-17g / m 2 ; (2) Dry and cure at 95-105°C for 50-70 seconds.

9. The preparation method according to claim 7, characterized in that: The silicone coating step comprises: (1) Using release paper with leather pattern as the carrier, the surface silicone is evenly coated on the release paper with a comma knife, and the coating thickness is controlled to be 23-27 μm; (2) Pre-curing at 75-85°C for 100-140 seconds to reach a semi-vulcanized state; (3) Evenly coat the bonding layer silicone on the pre-cured surface layer, controlling the total thickness to 45-55 μm; (4) Press the release paper coated with silicone and the polyimide film treated with primer, and use a 75-85KG heavy round pressure wheel and a 2.3-2.7KG cylinder pressure to shape; (5) Bake at 95-105°C for 160-200 seconds to complete vulcanization; (6) After cooling, peel off the release paper.

10. The preparation method according to claim 7, characterized in that: The surface treatment step comprises: (1) Use a 120-mesh rotating treatment wheel to evenly coat the surface treatment agent on the silica gel surface; (2) Bake in an oven at 125-135°C for 160-200 seconds.

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