TWI880505B - A high performance polyimide shielding film and preparation method thereof - Google Patents

Abstract

The present disclosure relates to a high performance polyimide shielding film, comprising a carrier film, a first polyimide layer, a second polyimide layer, and a conductive adhesive layer, wherein the second polyimide layer includes a co-polymer formed by the polymerization of multiple monomers containing diamine, silicon diamine, and acid anhydride. The present disclosure further provides a preparation method thereof.

Description

A high-performance polyimide shielding film and its preparation method

This disclosure belongs to the field of printed circuit board technology, and more particularly to high-performance polyimide shielding films and methods for preparing the same.

As electronic and communication products are becoming more multifunctional and complex, the circuit board needs to be lighter, thinner, shorter and smaller; and in terms of function, it needs strong and high-speed signal transmission. Therefore, the line density is bound to increase, the distance between the circuits on the substrate is getting closer, and the operating frequency is moving towards broadband. In addition, if the line layout and wiring are unreasonable, the electromagnetic interference (EMI) situation will become more and more serious. Therefore, it is necessary to effectively manage electromagnetic compatibility (EMC) to maintain the normal signal transmission of electronic products and improve reliability. The characteristics of being thin and flexible make flexible boards play an important role in the development of the portable information and communication electronics industry.

As electronic communication products become smaller, flexible boards must carry more and more powerful functions. On the other hand, as portable electronic products become smaller, the demand for high-density flexible board technology is also increasing. The functions are required to be powerful and high-frequency, high-density, thin-line, and high-flex. Currently, shielding films for film-type flexible printed circuit boards (FPC) have been launched on the market and are widely used in small electronic products such as mobile phones, digital cameras, and digital video cameras.

In shielding film design, in order to meet the requirements of product aesthetics, surface protection, high thickness step filling, etc., there is a demand for black polyimide films. Moreover, as the electronic products on the market are becoming thinner and lighter, important customers produce FPCs. In order to reduce the thickness of flexible board materials, customers require ultra-thin products to be designed. Polyimide manufacturers therefore reduce the film thickness. However, when the thinning thickness is designed to be 5 to 7.5μm, in addition to the appearance, it is difficult to achieve the current required matte surface (Gloss < 25GU), including general technical indicators such as mechanical strength, processing operability, and bendability. All of them cannot meet the requirements of industry standards and the yield rate is low.

In order to solve the bottleneck of the thin film and colored film of the polyimide manufacturers mentioned above in the application of shielding film, the colored polyimide film can be replaced by epoxy resin or polyurethane ink with release film to obtain a thinner insulating layer with a racemic optical surface. However, the mechanical strength, insulation, hardness, chemical resistance, heat resistance and high-grade application performance of this type of ink insulating layer are generally worse than those of black polyimide film. Therefore, the application of polyimide varnish system on release film was further extended. The colored polyimide varnish type insulation layer can be achieved by changing the resin or doping powder, and by improving the powder content ratio and particle size design, an insulation layer with multiple advantages such as high flame retardancy, high hardness, high thermal conductivity, and high mechanical properties can be obtained. Compared with the film produced by the casting process, the varnish type insulation layer has better dimensional stability because there is no residual stress from the stretching process. Compared with the film mode, the varnish type is directly generated on the release film, which is easier to process in the downstream process. However, the varnish-type insulation layer in the previous technology that uses a release film as a carrier layer has many deficiencies in mechanical properties because more powder is added to the insulation layer to achieve color. In addition, the carrier that it relies on as a release film often contains silicone in the release agent, which goes against the trend of downstream PCB manufacturers not wanting to have silicone residues, and it is easy to cause risks such as reduced reliability of the electroplating process.

Furthermore, in some high-thickness step filling requirements such as high current environments, or high-bending requirements such as folding screens and robotic arms that require a large number of bending parts and under total thickness restrictions, there are more stringent performance requirements for film materials and shielding materials. The elongation of polyimide films made by the biaxial stretching method on the market is usually 40 to 90%, and when the color is thinned, the elongation is generally lower than 60% or even lower than 40%. The above performance limitations also increase the necessity of developing high-performance polyimide films or inks, and the weakness of insufficient performance needs to be improved by adding other resins or additives.

As mentioned above, the FPC field still urgently needs a shielding film that can effectively manage electromagnetic compatibility, has stronger functions, high mechanical strength, high processing operability and high bendability, etc., which meet the requirements of industry standards and have a very high yield.

The present disclosure provides a polyimide shielding film, which is composed of a carrier film and a plurality of first polyimide layers, and includes at least one polyimide layer containing silicon; the polyimide film has the characteristic of high elongation, and its elongation can be greater than 60% or even 100%, and can be as high as more than 260%.

The present invention discloses a high-performance polyimide shielding film, which includes a carrier film; at least one first polyimide layer, which is formed by coating and curing a polyimide resin varnish layer on the carrier film; at least one second polyimide layer, which is formed by coating and curing a modified polyimide resin varnish layer on the first polyimide layer; and a conductive bonding layer, which is formed on the second polyimide layer. The first polyimide layer and the second polyimide layer are located between the carrier film and the conductive bonding layer; wherein the second polyimide layer comprises a silicon-containing resin formed by polymerization of monomers including diamine, anhydride and silicon diamine, and the thickness of the first polyimide layer is 1 to 50 μm, the thickness of the second polyimide layer is 1 to 50 μm, and the thickness of the conductive bonding layer is 3 to 25 μm.

In one embodiment of the present disclosure, the monomer further comprises isocyanate.

In one embodiment of the present disclosure, the carrier film includes at least one inorganic powder selected from the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder and clay, and the particle size is 10 to 20000 nm; the material of the carrier film is selected from the group consisting of polypropylene, biaxially stretched At least one resin selected from the group consisting of polypropylene, polyethylene terephthalate, polyimide, polyphenylene sulfide, polyethylene naphthalate, polyurethane and polyamide; the thickness of the carrier film is in the range of 12.5 to 250 μm; and the carrier film is used as the outer side of the insulating layer, and its surface roughness (Rz) is in the range of 0.001 to 10 μm, preferably 0.1 to 5.0 μm.

In one embodiment of the present disclosure, the molar percentage of silicon diamine in the second polyimide layer is 20 to 85% based on the total molar percentage of diamine and silicon diamine, and the elongation of the resin after the varnish is cured is affected by adjusting the ratio between the two.

In a specific embodiment of the present disclosure, the first polyimide layer includes 50 to 98 wt% of polyimide resin, 0 to 50 wt% of inorganic filler, 0 to 50 wt% of inorganic pigment or organic pigment, and 0 to 20 wt% of catalyst.

In a specific embodiment of the present disclosure, the catalyst is selected from at least one of the group consisting of 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole and 1-benzyl-2-phenylimidazole.

In a specific embodiment of the present disclosure, the polyimide resin material is at least one of dimaleimide resin, polyimide and polyamide imide, preferably at least one of the group consisting of polyimide and polyamide imide; and the inorganic filler is at least one selected from the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder and clay.

In a specific embodiment of the present disclosure, the high-performance polyimide shielding film includes a plurality of first polyimide layers and a plurality of second polyimide layers, and each of the first polyimide layers and the second polyimide layers are staggered and overlapped with each other, and the first polyimide layer contacting the carrier film has an inorganic filler greater than 0 to 50 wt%.

In a specific embodiment of the present disclosure, the first polyimide layer comprises an inorganic pigment or an organic pigment to form a non-natural colored insulating layer, wherein the inorganic pigment is selected from at least one of the group consisting of cadmium red, cadmium lemon yellow, orange cadmium yellow, titanium dioxide, carbon black, black iron oxide and black complex inorganic pigments, and the organic pigment is selected from at least one of the group consisting of aniline black, perylene black, anthraquinone black, benzidine yellow pigment, phthalocyanine blue and phthalocyanine green; and the total content of the inorganic pigment or organic pigment is greater than 0 to 50 wt% based on the total weight of the first polyimide layer.

In a specific embodiment of the present disclosure, the diamine is selected from 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)diaminobiphenyl (TFMB), 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenyl ether, bis[4-(3-aminophenoxy)phenyl]sulfonamide, bis[4-(4-aminophenoxy)phenyl]sulfonamide, 2, At least one of the group consisting of 2-bis[4-(4-aminophenoxy) phenyl]hexafluoropropane, bis[4-(4-aminophenoxy)phenyl]methane, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ethyl ether, bis[4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4'-aminophenoxy)benzene and 1,4-bis(4-aminophenoxy)benzene.

In one embodiment of the present disclosure, the silicon diamine has a structure of the following formula (I):

Wherein, R1 and R2 are independently selected from C1-C8 alkyl or C6-C12 aryl; R3 is selected from C1-C8 alkylene, unsubstituted or C6-C12 arylene substituted by C1-C8 alkylene, and n is 1 to 150.

In a specific embodiment of the present disclosure, the silicon diamine is selected from at least one of the following structures (II) to (IV), wherein n is 1 to 150:

In a specific embodiment of the present disclosure, the acid anhydride is at least one selected from the group consisting of hexafluorodianhydride (6FDA), bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (B1317), 1,2-ethylenedi[1,3-dihydro-1,3-dioxoisobenzofuran-5-carboxylate], 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, trimellitic anhydride (TMA) and cis-abiotic anhydride.

In a specific embodiment of the present disclosure, the molar ratio of the diamine and silicon diamine as a whole to the acid anhydride is 1/2.05 to 2.20.

In a specific embodiment of the present disclosure, the molar ratio of the diamine and silicon diamine as a whole to the dianhydride is 1/0.90 to 1.10.

In a specific embodiment of the present disclosure, the isocyanate is selected from at least one of the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and lysine diisocyanate.

In a specific embodiment of the present disclosure, the molar ratio of the diamine and silicon diamine as a whole to the isocyanate is 1/1.00 to 1.50.

In a specific embodiment of the present disclosure, the conductive bonding layer includes at least one resin selected from the group consisting of epoxy resin, acrylic resin, phenolic resin, polyurethane, polyimide and polyamide imide, and a plurality of conductive particles; wherein the material forming the plurality of conductive particles is selected from at least one of the group consisting of copper, silver, nickel, tin, gold, palladium, aluminum, chromium, titanium, zinc, carbon, nickel-gold alloy, gold-silver alloy, copper-nickel alloy, copper-silver alloy, nickel-silver alloy and copper-nickel-gold alloy; and the weight percentage of the plurality of conductive particles is 25 to 85% based on the total weight of the conductive bonding layer.

In a specific embodiment of the present disclosure, the high-performance polyimide shielding film includes a release layer disposed on the conductive bonding layer. The material of the release layer is at least one of polypropylene, biaxially oriented polypropylene or polyethylene terephthalate, or release paper.

In one embodiment of the present disclosure, by forming a polyimide layer through multi-layer coating and curing of a varnish-type resin, the micropores existing in the coating process can be solved, the micropore problem on the surface can be solved, and the mechanical properties can be improved.

In one embodiment of the present disclosure, the first polyimide layer is a plurality of layers, which not only solves the defects of coating appearance, but also improves the poor mechanical properties, the operability of production and processing, and the appearance.

In one embodiment of the present disclosure, inorganic powders having a particle size of 10 to 20,000 nm and selected from at least one of the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder and clay are added only to the first polyimide layer close to or in contact with the carrier film to increase the shielding property of the overall shielding film and change the surface roughness to match the carrier film for easy release, while no powder is added to other layers to improve the overall mechanical properties. In one embodiment of the present disclosure, the insulating layer and the carrier film are easier to separate through this morphology control, thereby improving the operability of the downstream terminal. At the same time, the colored carrier film and the insulating layer can have a better product appearance for customers after rapid pressure molding.

In one embodiment of the present disclosure, the second polyimide layer includes a silicon-containing resin formed by polymerization of monomers including diamine, anhydride and silane diamine, and the polymer main chain has an imide bond, and it also belongs to a polyimide resin. In another embodiment, during polymerization, a copolymer is formed by polymerization of multiple monomers, and its components include diamine, silane diamine, anhydride, tertiary amine and solvent, and optionally isocyanate to form a polyamide imide resin.

The present disclosure further provides a method for preparing a high-performance polyimide shielding film, comprising: coating a polyimide resin varnish layer on the carrier film, and curing the polyimide resin varnish layer at 50 to 180° C. to form the first polyimide layer; coating a modified polyimide resin varnish layer on the first polyimide layer, and curing the polyimide resin varnish layer at 50 to 180° C. to form the first polyimide layer; The modified polyimide resin varnish layer is cured at 180°C to form a second polyimide layer; the steps of forming the first polyimide layer and the second polyimide layer are repeated as needed so that the first polyimide layer and the second polyimide layer are alternately overlapped with each other; and the conductive bonding layer is formed on the second polyimide layer by coating or transfer.

In one embodiment of the present disclosure, before forming the second polyimide layer, the steps of coating and curing the polyimide resin varnish layer can be repeated to form a plurality of first polyimide layers. In addition, the steps of coating and curing the modified polyimide resin varnish layer can also be repeated to form a plurality of second polyimide layers.

The present disclosure further provides a method for preparing a high-performance polyimide shielding film, comprising: coating a polyimide resin varnish layer on the carrier film, and then drying the polyimide resin varnish layer to form the first polyimide layer; coating a modified polyimide resin varnish layer on the first polyimide layer, and then drying the modified polyimide resin varnish layer to form the first polyimide layer; Forming a second polyimide layer; Repeating the steps of forming the first polyimide layer and the second polyimide layer as needed, so that the first polyimide layer and the second polyimide layer are alternately overlapped with each other; Curing the first polyimide layer and the second polyimide layer at 50 to 180°C; and Forming the conductive bonding layer on the second polyimide layer by coating or transfer method.

In one embodiment of the present disclosure, before forming the second polyimide layer, the steps of coating and drying the polyimide resin varnish layer can be repeated to form a plurality of first polyimide layers. In addition, the steps of coating and drying the modified polyimide resin varnish layer can also be repeated to form a plurality of second polyimide layers, and then the first polyimide layer and the second polyimide layer are cured at 50 to 180°C.

The beneficial effects of this disclosure include at least the following:

The present disclosure provides a high-performance polyimide shielding film with a carrier film, which can be used as an insulating resin film in EMI shielding films, etc., and has high flame retardancy, insulating surface gloss and color adjustability, high shielding, high dimensional stability, high elongation and other mechanical properties, high surface hardness, and is particularly suitable for use in ultra-density assembly lines, high bending scenes, and wireless charging applications. The present disclosure solves the difficulty of the current stretch film on the market to achieve ultra-thin thickness and relatively single specifications under colorization, and replaces the black polyimide film with high cost and technical problems. By adding powder or surface treatment to the resin layer and the carrier film, the surface roughness and surface energy are changed to match the release force without using a release agent to eliminate the concern of organic silicon transfer and the cost is lower than using a release film. In addition, the present disclosure can effectively improve the shortcomings of insufficient performance such as mechanical strength by selecting and adding different resins and additives, especially achieving an elongation of >100% with an elongation greater than the technical bottleneck of 40 to 90% of the existing commercially available polyimide film (at a thickness of <8μm, the elongation is generally <60% or even <40%).

The specific innovations of this disclosure include at least the following:

1. The thin film produced by using the carrier film has a matching surface energy and roughness design between the carrier film and the insulating layer (polyimide layer), so there is no need to use a release agent on the carrier film and it has a surface matte property. The high surface energy of the insulating layer is easy to use in the bonding and bonding process, and there is no need to use additional surface treatment processes such as corona.

2. The use of multi-layer coating composition makes it easy to take into account various characteristics and match the downstream processing requirements, so that the insulation layer has excellent scratch resistance, wear resistance and excellent high-step filling properties.

3. The carrier film is coated with varnish, which is cheaper than the film produced by the casting process, and no additional film is required in the downstream process to avoid tearing, etc., making it easier to operate and process.

4. Compared with the film produced by the casting process, the varnish type insulation layer has better dimensional stability because there is no residual stress from the stretching process.

5. By adding other resins or additives to improve the weakness of insufficient mechanical properties, especially by using silicon diamine to partially replace the original diamine, the overall elongation of the insulating layer and the shielding film can exceed 60% and even up to 260%.

100: Shielding film

101: Carrier film

102: first polyimide layer

103: Second polyimide layer

104: Conductive bonding layer

105: Release layer

The implementation method of the present disclosure is described by referring to the exemplary drawings.

Figure 1 is one of the structural schematic diagrams of the high-performance polyimide shielding film disclosed herein.

Figure 2 is the second structural schematic diagram of the high-performance polyimide shielding film disclosed herein.

The following will provide a clearer and more complete description of the technical solutions described in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the many embodiments covered by the present disclosure and are not intended to limit the scope of the present disclosure. The present disclosure can also be implemented or applied in similar or different embodiments. Other embodiments obtained by a person of ordinary skill in the art without any creation, such as modification, change, replacement of a certain element or its combination, etc., are all included in the scope of the present disclosure.

Please further note that the singular forms "a", "an" and "the" described herein are intended to include plural referents unless expressly limited to one referent. In addition, the term "or" and the term "and/or" are interchangeable unless the context clearly indicates otherwise.

The term "about" as used herein means that the error or range of the numerical value, numerical range or ratio described is within 20% of the numerical value, numerical range or ratio, preferably within 10%, and more preferably within 5%. The quantitative values described herein are approximate values, which means that they can also be inferred if the term "about" is not used. The numerical range described herein covers all numerical values falling within the numerical range, for example, the numerical range of 3 to 7 μm covers 2.4 μm, 3 μm, 3.01 μm, 3.1 μm, 3.5 μm, etc., and also covers all sub-ranges falling within the numerical range, and the sub-ranges are surrounded by each numerical value falling within the numerical range, for example, the numerical range of 3 to 7 μm covers sub-ranges such as 3 to 6 μm, 4 to 7 μm, and 4 to 6 μm.

The terms "include", "comprise", "contain", "have", etc. described herein refer to the existence of certain elements (such as components or steps, etc.) in the disclosed objects, methods, uses, etc., and unless the context clearly indicates otherwise, those unrecorded and unspecified elements are also openly present in the disclosed objects, methods, uses, regardless of whether they are necessary or not. That is, those unrecorded and unspecified elements are not restrictedly excluded.

As shown in FIG. 1 or FIG. 2 , the present disclosure relates to a high-performance polyimide shielding film 100, comprising: a carrier film 101, a first polyimide layer 102, a second polyimide layer 103, a conductive bonding layer 104 and a release layer 105.

As shown in FIG. 1 or FIG. 2, the present disclosure provides a method for preparing a high-performance polyimide shielding film, comprising: coating a polyimide resin varnish layer on the carrier film 101, and curing the polyimide resin varnish layer at 50 to 180°C to form the first polyimide layer 102; coating a modified polyimide resin varnish layer on the first polyimide layer 102, and curing the modified polyimide resin varnish layer at 50 to 180°C to form a second polyimide layer 103; forming the conductive bonding layer 104 on the second polyimide layer 103 by coating or transfer method; and laminating a release layer 105.

In another specific embodiment of the present disclosure, as shown in FIG. 2 , the steps of forming the first polyimide layer 102 and the second polyimide layer 103 are repeated so that the first polyimide layer 102 and the second polyimide layer 103 are alternately overlapped with each other; then the conductive bonding layer 104 is formed on the second polyimide layer 103 by coating or transfer method; and the release layer 105 is attached.

In a specific embodiment of the present disclosure, the present disclosure also provides a method for preparing a high-performance polyimide shielding film, which includes: coating a polyimide resin varnish layer on the carrier film 101, and then drying the polyimide resin varnish layer to form the first polyimide layer 102; coating a modified polyimide layer on the first polyimide layer 102; Modified polyimide resin varnish layer, and then dried the modified polyimide resin varnish layer to form a second polyimide layer 103; cured the first polyimide layer 102 and the second polyimide layer 103 at 50 to 180°C; and formed the conductive bonding layer 104 on the second polyimide layer 103 by coating or transfer method.

In another specific embodiment of the present disclosure, as shown in FIG. 2 , the steps of forming the first polyimide layer 102 and the second polyimide layer 103 are repeated so that the first polyimide layer 102 and the second polyimide layer 103 are alternately overlapped with each other; then the first polyimide layer 102 and the second polyimide layer 103 are cured at 50 to 180° C.; the conductive bonding layer 104 is formed on the second polyimide layer 103 by coating or transfer method; and the release layer 105 is attached.

In a specific embodiment of the present disclosure, inorganic powder with a particle size of 10 to 20,000 nm and selected from at least one of the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder and clay can be added only to the first polyimide layer 102 close to or in contact with the carrier film to increase the shielding property of the overall covering film and change the surface roughness to match the carrier film for easy release, while no powder is added to other layers to improve the overall mechanical properties. The particle size of inorganic powders is, for example, 20, 30, 40, 50, 100, 200, 250, 300, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 5000, 5500, 6000, 7000, 10000, 15000, 17500, 18000, 19000 or 20000 nm.

In a specific embodiment of the present disclosure, the silicone-containing resin of the second polyimide layer is obtained by polymerization of components including diamine, silicon diamine, acid anhydride, isocyanate, tertiary amine and solvent.

In a specific embodiment of the present disclosure, the total thickness of the first polyimide layer 102 is 1 to 50 μm, for example, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 μm; the thickness of the second polyimide layer 103 is 1 to 50 μm, for example, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 μm; the thickness of the conductive bonding layer is 3 to 25 μm, for example, 3, 5, 10, 15, 20 or 25 μm.

In a specific embodiment of the present disclosure, the carrier film includes at least one inorganic powder selected from the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder and clay and having a particle size of 10 to 20000 nm. In a specific embodiment, the particle size of the inorganic powder is, for example, 20, 30, 40, 50, 100, 200, 250, 300, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 5000, 5500, 6000, 7000, 10000, 15000, 17500, 18000, 19000 or 20000 nm.

In a specific embodiment of the present disclosure, the material of the carrier film is at least one of polypropylene, biaxially oriented polypropylene, polyethylene terephthalate, polyimide, polyphenylene sulfide, polyethylene naphthalate, polyurethane, and polyamide; the thickness of the carrier film ranges from 12.5 to 250 μm, for example, 12.5, 17.5, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240 or 250 μm.

In a specific embodiment of the present disclosure, the carrier film is used on the outer side of the insulating layer, and its surface roughness (Rz) is 0.001 to 10 μm, for example, 0.01 to 8 μm, 0.5 to 7 μm, 0.7 to 1 μm, preferably 0.1 to 5.0 μm. Through this morphological control, the insulating layer and the carrier film are easier to separate, thereby improving the operability of the downstream terminal. At the same time, the colored carrier film and the insulating layer can have a better product appearance for customers after rapid pressure molding.

In a specific embodiment of the present disclosure, the molar percentage of silicon diamine in the second polyimide layer is 20 to 85%, for example, 20, 30, 40, 50, 60, 70, 80 or 85%, based on the total moles of diamine and silicon diamine in the second polyimide layer.

In a specific embodiment of the present disclosure, the first polyimide layer includes or consists of the following components: 50 to 98 wt% of polyimide resin, for example, 50, 60, 65, 70, 75, 80, 85, 90 or 98 wt%; 0 to 50 wt% of inorganic filler, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 wt%; 0 to 50 wt% of inorganic pigment or organic pigment, for example, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 wt%; 0 to 20 wt% of catalyst, for example, 0, 2.5, 5, 7.5, 10, 12.5, 15, 17.5 or 20 wt%.

In a specific embodiment of the present disclosure, the polyimide resin material is at least one of dimaleimide resin, polyimide and polyamide imide, preferably at least one of the group consisting of polyimide and polyamide imide.

In a specific embodiment of the present disclosure, the inorganic filler is at least one selected from the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder and clay.

In a specific embodiment of the present disclosure, the high-performance polyimide shielding film includes a plurality of first polyimide layers and a plurality of second polyimide layers, and each of the first polyimide layers and the second polyimide layers are staggered and overlapped with each other, and the first polyimide layer contacting the carrier film has an inorganic filler greater than 0 to 50 wt%.

In a specific embodiment of the present disclosure, the first polyimide layer comprises an inorganic pigment or an organic pigment, wherein the inorganic pigment is selected from at least one of the group consisting of cadmium red, cadmium lemon yellow, orange cadmium yellow, titanium dioxide, carbon black, black iron oxide and black complex inorganic pigments, and the organic pigment is selected from at least one of the group consisting of aniline black, perylene black, anthraquinone black, benzidine yellow pigment, phthalocyanine blue and phthalocyanine green; and the total content of the inorganic pigment or organic pigment is greater than 0 to 50 wt% based on the total weight of the first polyimide layer.

The surface hardness of the varnish layer on the market is mostly HB-2H. The surface is fragile and easily scratched, affecting the appearance and mechanical properties. The added powder helps to improve its hardness, making it reach 2H-6H. At the same time, the increase of powder in different proportions also has different flame retardancy. When the proportion of one or more mixed powders of inorganic powders such as titanium dioxide, silicon dioxide, aluminum oxide, aluminum hydroxide, calcium carbonate, etc. is higher, the higher the flame retardancy. When higher hardness is required, it is preferably a mixture of one or more of titanium dioxide, silicon dioxide, etc. When higher flame retardancy is required, it is preferably a mixture of one or more inorganic substances such as aluminum hydroxide, aluminum oxide, calcium carbonate and one or more flame retardant compounds such as halogens, phosphorus, nitrogen or boron.

In a specific embodiment of the present disclosure, the diamine is selected from 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2'-bis(trifluoromethyl)diaminobiphenyl (TFMB), 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenyl ether, bis[4-(3-aminophenoxy)phenyl]sulfonamide, bis[4-(4-aminophenoxy)phenyl]sulfonamide, 2,2-bis[4-(4-aminophenoxy)phenyl]sulfonamide, At least one of the group consisting of bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, bis[4-(4-aminophenoxy)phenyl]methane, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ethyl ether, bis[4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4'-aminophenoxy)benzene and 1,4-bis(4-aminophenoxy)benzene; in a specific embodiment of the present disclosure, the silicon diamine has a structure of the following formula (I):

Wherein, R1 and R2 are independently selected from C1-C8 alkyl or C6-C12 aryl; R3 is selected from C1-C8 alkylene, unsubstituted or C1-C8 alkylene substituted C6-C12 arylene, and n is 1 to 150, for example, 1, 5, 10, 15, 20, 30, 40, 50, 70, 60, 80, 90, 100, 120, 130, 140 or 150.

In a specific embodiment of the present disclosure, the silicon diamine is selected from at least one of the following structures (II) to (IV), wherein n is 1 to 150:

及

and

In a specific embodiment of the present disclosure, the second polyimide layer has repeating units of the following formula (V):

In a specific embodiment of the present disclosure, the acid anhydride is selected from at least one of the group consisting of hexafluorodianhydride (6FDA), bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (B1317), 1,2-ethylenedi[1,3-dihydro-1,3-dioxoisobenzofuran-5-carboxylate], 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, trimellitic anhydride (TMA) and cis-abiotic anhydride.

In a specific embodiment of the present disclosure, in the synthesis of a silicone-containing resin, the molar ratio of the total diamine and silicon diamine to the acid anhydride is 1/2.05 to 2.20, for example, 2.05, 2.07, 2.08, 2.10, 2.12, 2.14, 2.16, 2.18 or 2.20; in the synthesis of a silicone-containing resin, the molar ratio of the total diamine and silicon diamine to the dianhydride is 1/0.90 to 1.10, for example, 0.90, 1.00 or 1.10.

In a specific embodiment of the present disclosure, the isocyanate is selected from at least one of the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, lysine diisocyanate, etc.; in the synthesis of the silicone-containing resin, the molar ratio of the total diamine and silicon diamine to the isocyanate is 1/1.00 to 1.50, for example, 1.10, 1.20, 1.30, 1.40 or 1.50.

In a specific embodiment of the present disclosure, the tertiary amine is selected from at least one of the group consisting of triethylamine (Et3N), isoquinoline, pyridine, N-ethylpiperidine and benzimidazole; the amount added as a catalyst is 0 to 3.0% by weight, for example 0.5, 1, 1.5, 2.0, 2.5 or 3.0%.

In a specific embodiment of the present disclosure, the solvent is selected from at least one of the group consisting of N-methylpyrrolidone, γ-butyrolactone, cyclohexanone, acetone, butanone, N,N-dimethylformamide, N,N-dimethylacetamide, pyridine, cyclohexane, dichloromethane, tetrahydrofuran, ethyl acetate, acetonitrile, 1,2-dichloroethane, trichloroethylene, triethylamine, 4-methyl-2-pentanone, toluene and xylene.

In a specific embodiment of the present disclosure, the conductive bonding layer includes at least one resin selected from the group consisting of epoxy resin, acrylic resin, phenolic resin, polyurethane, polyimide and polyamide imide, and a plurality of conductive particles; wherein the material forming the plurality of conductive particles is selected from at least one of the group consisting of copper, silver, nickel, tin, gold, palladium, aluminum, chromium, titanium, zinc, carbon, nickel-gold alloy, gold-silver alloy, copper-nickel alloy, copper-silver alloy, nickel-silver alloy and copper-nickel-gold alloy; and the content of the plurality of conductive particles is 25 to 85wt% based on the total weight of the conductive bonding layer.

In a specific embodiment of the present disclosure, the content of the plurality of conductive particles is 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 or 85 wt % based on the total weight of the conductive bonding layer.

Examples

Example 1: Highly elongated polyamide imide

To compare polyamide imide solutions with different composition ratios (Examples 1 to 7 and Comparative Example 1), the following synthesis steps were performed: different weights of BAPP and silicon diamine were added to NMP, nitrogen was introduced, and stirred and dissolved at 80°C; TMA (4.03g) was added and reacted at 80°C for 1 hour; toluene (5 to 15mL) was added and the temperature was raised to 170°C to evaporate the water, and finally the temperature was raised to 190°C to evaporate the toluene; after returning to room temperature, MDI (3g) and Et3N were added, and the temperature was raised to 120°C for 3 hours to obtain soluble polyamide imide solutions with different composition ratios as shown in Table 1.1.

Table 1.2 shows the tensile strength, elastic modulus and elongation of the polyimide film formed by the soluble polyamide imide solution of Examples 1 to 7. Each polyimide film is formed by coating the soluble polyamide imide solution of Examples 1 to 7 on the carrier film, heating at 50℃, 110℃, 150℃, 180℃, 180℃, 130℃, 50℃ for 1 minute between each temperature, and curing for a total of 7 minutes. As shown in Table 1.2, the tensile strength and elastic modulus of Examples 1 to 7 are less than those of Comparative Example 1, and the elongation is higher than that of Comparative Example 1.

Table 1.1

BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane; Silanediamine: Shin-Etsu KF-8012, molecular weight 4400; TMA: trimellitic anhydride; MDI: 4,4'-diphenylmethane diisocyanate; Et3N: triethylamine; NMP: N-methylpyrrolidone.

Table 1.2

The mechanical properties of the embodiment corresponding to Table 1.1 are shown in Table 1.2

Example 2: Highly elongated polyimide

To compare polyimide solutions with different composition ratios (Examples 8 to 14 and Comparative Example 2), the following synthesis steps were performed: under nitrogen, monomers were added to NMP at 80°C, TFMB and silicon diamine were added first, and then 6FDA (21.99g) and B1317 (12.41g) were added; 6FDA and B1317 were added in equal proportions, and the additional amount was 5% of the added amount; the temperature was raised to 150°C, and N-ethylpiperidine was added; the temperature was raised to 190°C and reacted for 4 hours to obtain soluble polyimide solutions with different composition ratios as shown in Table 2.1.

Table 2.2 shows the tensile strength, elastic modulus and elongation of the polyimide films formed by the soluble polyimide solutions of Examples 8 to 14. Each polyimide film is formed by coating the soluble polyimide solutions of Examples 8 to 14 on the carrier film, heating at 50°C, 110°C, 150°C, 180°C, 180°C, 130°C, and 50°C for 7 minutes between each temperature, and heating for a total of 6 minutes. As shown in Table 2.2, the tensile strength and elastic modulus of Examples 8 to 14 are less than those of Comparative Example 1, and the elongation is higher than that of Comparative Example 2.

Table 2.1

TFMB: 2,2'-bis(trifluoromethyl)diaminobiphenyl; Silanediamine: Shin-Etsu KF-8012, molecular weight 4400; 6FDA: hexafluorodianhydride; B1317: bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride; NMP: N-methylpyrrolidone.

Table 2.2

The mechanical properties of the embodiment corresponding to Table 2.1 are shown in Table 2.2

Example 3: First polyimide layer and carrier film with different proportions of carbon black content

The first polyimide layer of this example is obtained by the following method. First, under nitrogen, add monomers to 349g NMP in sequence at 80°C, first add 32.02g 2,2'-bis(trifluoromethyl)diaminobiphenyl (TFMB) and then add 21.99g hexafluorodianhydride (6FDA) and 12.41g bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (B1317). Add 6FDA and B1317 in equal proportions, the additional amount is 5% of the added amount. Raise the temperature to 150°C and add 0.80g N-ethylpiperidine. The temperature was raised to 190°C and reacted for 4 hours to obtain a soluble polyimide solution, and different contents of carbon black and black pigment were added according to Table 3 (the components included 50 weight percent of black iron oxide, 15 weight percent of black complex (acid black 220), 20 weight percent of aniline black, 10 weight percent of carbon black and 5 weight percent of titanium black). Then, after applying the soluble polyimide solution on the carrier film, it was heated at 50°C, 110°C, 150°C, 180°C, 180°C, 130°C, and 50°C for 1 minute between each temperature, and heated for a total of 7 minutes to cure to form the first polyimide layer.

Taking the first polyimide layer with a thickness of 5 μm and the carrier film with a thickness of 25 μm as an example, the effects of different proportions of carbon black content (black dye is an inorganic black pigment with added carbon black) in the first polyimide layer and the carrier film are compared. The relevant properties of Examples 15 to 30 are shown in Table 3.

As shown in Table 3, the roughness matching between the first polyimide layer and the carrier film mainly lies in making the first polyimide layer or the carrier layer or both have a certain roughness, which is mainly achieved by adding powder to reduce the release force to the required range. For example, in the case of Example 28, when there is no addition, the release force is too large and cannot be released. Generally, to solve this situation, a release agent is added to the carrier, which is different from the method of this case. The change in the roughness of the carrier will affect the roughness of the insulating layer of the finished product. The rougher the surface of the carrier, the rougher the surface of the insulating layer.

Table 3

Example 4: Comparison of polyimide films

As shown in Table 4 below, Examples A1 to A6 are films made from structural examples of different specifications (the carrier has been removed), Comparative Examples B1 and B2 are polyimide films of similar specifications using uniaxially stretched films on the market, Comparative Examples B3 and B4 are polyimide films of similar specifications using biaxially stretched films on the market, and Comparative Examples B5 and B6 are films made from Comparative Examples 1 and 2 in Tables 1.2 and 2.2 under the same first polyimide varnish, but with the high-stretched polyimide varnish part being replaced (the carrier has been removed).

The varnish layer coated with the first polyimide layer of Examples A1 to A6 and Comparative Examples B5 and B6 is a polyimide resin layer having amide bonds and imide bonds in its resin skeleton, and the solvent is cyclohexanone. The second polyimide layer of Examples A1 to A6 uses Examples 3, 5 and 7 in Table 1.1 and Examples 9, 11 and 13 in Table 2.1, respectively. Comparative Examples B1 and B2 are polyimide films HB-N from Shenzhen Ruihuatai, and Comparative Examples B3 and B4 are DuPont black polyimide films Kapton. The polyamide imide resin used in the polyamide resin varnish coated on the first polyimide layer in Examples A1 to A6 has the following structural formula:

n=25 to 35;

The catalyst used is 2E4MZ (diethyltetramethylimidazole), the flame retardant is Clariant, model: Exolit® OP 935, the inorganic filler is SiO ₂ , and the inorganic pigment is carbon black. For Examples A1 to A6, the first polyimide layer has a resin weight percentage of 80%, an inorganic filler weight percentage of 5%, an inorganic pigment weight percentage of 10%, and a catalyst weight percentage of 5%.

As shown in Table 4, all examples have good elongation and dimensional stability, and the overall performance meets the industry's requirements. Among them, between Examples A1 to A6, we can improve the mechanical strength (tensile strength, elongation and elastic modulus) of the polymer film, especially the elongation, by adjusting the formula ratio of Table 1 or Table 2. Comparative Examples B1 and B2 are polyimide films produced by casting without biaxial stretching. Although the mechanical strength is acceptable, the dimensional stability of the finished product is the worst.

Table 4

Example 5: Comparison of shielding film related properties

The examples and comparative examples obtained in Table 4 are respectively taken from Examples A2, A3, A6 and Comparative Example B3, and polyurethane ink as the insulating layer/ink for the shielding film in Examples E1 to E3 and Comparative Examples F1 and F2 in Table 5. The above are all matched with the same conductive glue composition (60% of silver-clad copper metal powder, 10% of 4,4'-diaminodiphenylsulfone as curing agent, and the rest is made of bisphenol A epoxy resin BE501A80 (purchased from Changchun Chemical) and acrylic resin JT-A1767 (purchased from Qiaoyi Technology), mixed in a weight ratio of 1:1), to make Examples E1 to E3 and Comparative Examples F1 and F2.

From the data in Table 5, it can be seen that the shielding film obtained in the embodiment has good related properties, can meet the customer's SMT simulation test and the on-resistance value after SMT, and can effectively meet the special process requirements of the customer.

Table 5

1. Peeling strength test: Test according to IPC-TM-650 2.4.9 D.

2. Solderability test: Test according to IPC-TM-650 2.4.13 F.

3. Thermal stress test: Test according to IPC-TM-650 2.6.8.1 (9/91).

4. Surface hardness test: According to the standard ASTM D3363, use a pencil to perform hardness test. (Test the insulation layer/first polyimide layer)

5. Electromagnetic shielding performance test: Tested in accordance with GB/T 30142-2013 "Measurement Method for Shielding Effectiveness of Planar Electromagnetic Shielding Materials".

6. Gloss value test: Prepare a sample larger than 3*8cm in size, measure the sample in the longitudinal direction (MD direction) with a gloss meter, and read the 60° value as the measurement value.

7. Insulation resistance test: Cut the unmetallized shielding film semi-finished product into A4 size, apply epoxy resin glue on the bright surface of 1Oz thick electrolytic copper foil, laminator the cut semi-finished product, and cure it at 160℃*1H to obtain the test sample. Use the ohm gear of the digital multimeter to test the resistance value between the conductors, and measure 6 groups of 8 test lines with a length of 6cm and a width of 0.8cm along the MD direction (1-8) and take the average value.

8. Resistance test: Use a handheld digital four-point probe to measure two groups of 30mm*514mm (MD*TD) samples along the MD direction and three groups along the TD direction (transverse direction), a total of six groups of data to obtain the average result.

9. Customer-side SMT simulation test: heat up to 120℃ at 2℃/sec, preheat for 2 minutes, heat up to 245℃ at 3℃/sec, maintain for 0.5 minutes, cool down to room temperature at 4℃/sec, then take out to check if there is any crack on the appearance.

Preparation of SMT test products: Prepare the polyimide film of this example as the mask film, as well as AHICX025SMN (Yasen Electronics, yellow cover film) and AHISR12011SHN (Yasen Electronics, single-sided plastic calender substrate), etch the circuit on the substrate and press the cover film, open circular holes with 0.8mm and 1.0mm apertures on the yellow cover film, press the mask film of the embodiment with a fast press (parameters: 180℃*100Kg*120Sec) and mature at 160℃ for 1 hour. Then, the test product composed of this mask film/cover film/calender substrate was subjected to SMT (process up to 245℃) 6 times, and the resistance between the substrate circuits was measured. It was considered to have passed if it was less than 2Ω.

10.Tensile strength, elastic modulus, and elongation test: Test in accordance with IPC-TM-650 2.4.19C (5/98).

11. Dimensional stability: Use a two-dimensional coordinate measuring instrument and follow the IPC-TM-650 2.2.4C specification.

12. High thickness step resistance test:

The polyimide film used as the mask film in this example, as well as AHICX025SMN (Yasen Electronics, yellow cover film), AHISR12011SHN (Yasen Electronics, single-sided adhesive calendering substrate), and AHBQX525/725/B25 GH1N (Yasen Electronics, black PI reinforcement board) are prepared. The 525 of the PI reinforcement board represents a total thickness of 150μm, and 725 and B25 represent a total thickness of 200μm and 300μm respectively.

Etch the circuit on the substrate and press the cover film and place the PI reinforcement board locally. Open a 2.0mm diameter round hole on the yellow cover film to make a high step difference sample. Use a vacuum fast press to press the mask film (parameters: 180℃*20Kg*180Sec) on the high step difference sample, cure at 160℃ for one hour, then bleach solder 3 times at 288℃*10sec, test the resistance between the substrate circuits, and less than 2Ω is considered to meet the thickness step difference.

The above is only an embodiment of the present disclosure and does not limit the patent scope of the present disclosure. Any equivalent structural changes made using the present specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present disclosure.

100: Shielding film

101: Carrier film

102: first polyimide layer

103: Second polyimide layer

104: Conductive bonding layer

105: Release layer

Claims (20)

A high-performance polyimide shielding film comprises: a carrier film; at least one first polyimide layer formed by coating and curing a polyimide resin varnish layer on the carrier film; at least one second polyimide layer formed by coating and curing a modified polyimide resin varnish layer on the first polyimide layer; and a conductive bonding layer formed on the second polyimide layer, so that the first polyimide layer and the second polyimide layer are located between the carrier film and the conductive bonding layer; wherein the first polyimide layer The amine layer includes 50 to 98 wt% of a polyimide resin, 5 to 50 wt% of an inorganic filler, 5 to 50 wt% of an inorganic pigment or an organic pigment, and 0 to 20 wt% of a catalyst, the second polyimide layer includes a silicon-containing resin formed by polymerization of monomers including diamine, anhydride, and silicon diamine, and wherein the thickness of the first polyimide layer is 1 to 50 μm, the thickness of the second polyimide layer is 1 to 50 μm, and the thickness of the conductive bonding layer is 3 to 25 μm. A high-performance polyimide shielding film as described in claim 1, wherein the monomer comprises isocyanate. A high-performance polyimide shielding film as described in claim 1, wherein the carrier film includes at least one inorganic powder selected from the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder and clay and having a particle size of 10 to 20000 nm; and at least one resin selected from the group consisting of polypropylene, biaxially oriented polypropylene, polyethylene terephthalate, polyimide, polyphenylene sulfide, polyethylene naphthalate, polyurethane and polyamide, and the carrier film has a thickness of 12.5 to 250 μm and a surface roughness of 0.001 to 10 μm. A high-performance polyimide shielding film as described in claim 1, wherein the molar percentage of silicon diamine in the second polyimide layer is 20 to 85% based on the total molar percentage of diamine and silicon diamine. The high-performance polyimide shielding film as described in claim 1, wherein the inorganic filler comprises at least one selected from the group consisting of calcium sulfate, carbon black, silicon dioxide, titanium dioxide, zinc sulfide, zirconium oxide, calcium carbonate, silicon carbide, boron nitride, aluminum oxide, talc, aluminum nitride, glass powder and clay. The high-performance polyimide shielding film as described in claim 1 comprises a plurality of first polyimide layers and a plurality of second polyimide layers, and each of the first polyimide layers and the second polyimide layers are staggered and overlapped with each other, and the first polyimide layer contacting the carrier film has an inorganic filler greater than 0 to 50 wt%. The high-performance polyimide shielding film as described in claim 1, wherein the first polyimide layer comprises an inorganic pigment or an organic pigment, wherein the inorganic pigment is selected from at least one of the group consisting of cadmium red, cadmium lemon yellow, orange cadmium yellow, titanium dioxide, carbon black, black iron oxide and black complex inorganic pigments, and the organic pigment is selected from at least one of the group consisting of aniline black, perylene black, anthraquinone black, benzidine yellow pigment, phthalocyanine blue and phthalocyanine green; and the total content of the inorganic pigment or organic pigment is greater than 0 to 50wt% based on the total weight of the first polyimide layer. A high-performance polyimide shielding film as described in claim 1, wherein the diamine is selected from 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis(trifluoromethyl)diaminobiphenyl, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenyl ether, bis[4-(3-aminophenoxy)phenyl]sulfonamide, bis[4-(4-aminophenoxy)phenyl]sulfonamide, 2, At least one of the group consisting of 2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, bis[4-(4-aminophenoxy)phenyl]methane, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ethyl ether, bis[4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4'-aminophenoxy)benzene and 1,4-bis(4-aminophenoxy)benzene. The high-performance polyimide shielding film as described in claim 1, wherein the silicon diamine has a structure of the following formula (I):

Wherein, R1 and R2 are independently selected from C1-C8 alkyl or C6-C12 aryl; R3 is selected from C1-C8 alkylene, unsubstituted or C6-C12 arylene which is substituted by C1-C8 alkyl, and n is 1 to 150. The high-performance polyimide shielding film as described in claim 9, wherein the silicon diamine is selected from at least one of the following structures (II) to (IV), wherein n is 1 to 150:

The high-performance polyimide barrier film as described in claim 1, wherein the acid anhydride is at least one selected from the group consisting of hexafluorodianhydride (6FDA), bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (B1317), 1,2-ethylenebis[1,3-dihydro-1,3-dioxoisobenzofuran-5-carboxylate], 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, trimellitic anhydride (TMA) and cis-abiotic anhydride. The high-performance polyimide shielding film as described in claim 1, wherein the molar ratio of the diamine and silicon diamine as a whole to the anhydride is 1/2.05 to 1/2.20. The high-performance polyimide shielding film as described in claim 1, wherein the anhydride in the second polyimide layer includes dianhydride, and the molar ratio of the diamine and silicon diamine as a whole to the dianhydride is 1/0.90 to 1/1.10. The high-performance polyimide shielding film as described in claim 2, wherein the isocyanate is selected from at least one of the group consisting of 4,4'-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and lysine diisocyanate. The high-performance polyimide shielding film as described in claim 2, wherein the molar ratio of the diamine and silicon diamine as a whole to the isocyanate is 1/1.00 to 1/1.50. The high-performance polyimide shielding film as described in claim 1, wherein the conductive bonding layer comprises at least one resin selected from the group consisting of epoxy resin, acrylic resin, phenolic resin, polyurethane, polyimide and polyamide imide, and a plurality of conductive particles; wherein the material forming the plurality of conductive particles is selected from at least one of the group consisting of copper, silver, nickel, tin, gold, palladium, aluminum, chromium, titanium, zinc, carbon, nickel-gold alloy, gold-silver alloy, copper-nickel alloy, copper-silver alloy, nickel-silver alloy and copper-nickel-gold alloy; and the content of the plurality of conductive particles is 25 to 85wt% based on the total weight of the conductive bonding layer. The high-performance polyimide shielding film as described in claim 1 further includes a release layer disposed on the conductive bonding layer. A method for preparing a high-performance polyimide shielding film as described in claim 1, comprising: coating a polyimide resin varnish layer on the carrier film, and curing the polyimide resin varnish layer at 50 to 180°C to form the first polyimide layer; coating a modified polyimide resin varnish layer on the first polyimide layer, and curing the modified polyimide resin varnish layer at 50 to 180°C to form a second polyimide layer; and forming the conductive bonding layer on the second polyimide layer by coating or transfer. A method for preparing a high-performance polyimide shielding film as described in claim 1, comprising: coating a polyimide resin varnish layer on the carrier film, and then drying the polyimide resin varnish layer to form the first polyimide layer; coating a modified polyimide resin varnish layer on the first polyimide layer, and then drying the modified polyimide resin varnish layer to form a second polyimide layer; curing the first polyimide layer and the second polyimide layer at 50 to 180°C; and forming the conductive bonding layer on the second polyimide layer by coating or transfer. A method for preparing a high-performance polyimide shielding film as described in claim 18 or 19, after forming the second polyimide layer, further comprises the step of repeatedly forming the first polyimide layer and the second polyimide layer, so that the first polyimide layer and the second polyimide layer are alternately overlapped with each other.

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