Polyimide adhesive film, method of making and use thereof

Abstract

The application provides a polyimide adhesive film, a preparation method and application thereof. The polyimide adhesive film comprises the following components in parts by weight: 100 parts of a polyimide resin matrix; and, based on 100 parts of the polyimide resin matrix, 50-80 parts of a copolymer modifier, wherein the copolymer modifier comprises one or more of an epoxy-based diamine, p-aminoaniline, p-hydroxyaniline, allyl bisphenol A and hyperbranched siloxane; 4-35 parts of a toughening agent; and 40-100 parts of a special resin, wherein the special resin has a thermal decomposition temperature greater than or equal to 250 DEG C. The polyimide adhesive film has excellent bonding strength and anti-creep capacity at high temperatures, and can reduce the cost of the polyimide adhesive film.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyimide adhesive film, and particularly relates to a polyimide adhesive film, a preparation method and application thereof. BACKGROUND

[0002] Polyimide resin is widely used in aerospace, electronic manufacturing and other fields due to its excellent high-temperature resistance and chemical stability. The main component of the polyimide adhesive film is polyimide, which is a high molecular polymer with a cyclic imide functional group in the main chain.

[0003] The preparation method of the polyimide adhesive film is usually to dissolve the polyimide resin in an organic solvent, heat and stir to form a polyimide solution, and then cast the polyimide solution on a substrate to form a polyimide adhesive film after drying. The properties of the polyimide adhesive film are closely related to the properties of the polyimide resin. However, the traditional polyimide resin exhibits low bonding strength in an extreme high-temperature environment and is prone to creep, which limits its application in high-performance structural adhesive films. SUMMARY

[0004] The application provides a polyimide adhesive film, a preparation method and application thereof, aiming to improve the bonding strength and creep resistance of the polyimide adhesive film at high temperatures, and reduce the cost of the polyimide adhesive film.

[0005] The first aspect of the application provides a polyimide adhesive film, which comprises the following components in parts by weight:

[0006] 100 parts of a polyimide resin matrix; and, based on 100 parts of the polyimide resin matrix,

[0007] 50-80 parts of a copolymer modifier; the copolymer modifier comprises one or more of an epoxy-based diamine, p-aminoaniline, p-hydroxyaniline, allyl bisphenol A and hyperbranched siloxane;

[0008] 4-35 parts of a toughening agent;

[0009] 40-100 parts of a special resin; the thermal decomposition temperature of the special resin is greater than or equal to 250℃.

[0010] In a feasible implementation manner of the first aspect of the application, the polyimide resin matrix comprises a copolymer of a diamine compound and a dianhydride compound; the diamine compound comprises at least two of a methyl-containing diamine compound, an ether bond-containing diamine compound, a ketone group-containing diamine compound, an ether bond and ketone group structure-containing diamine compound, a fluorinated methyl structure-containing diamine compound and a benzene ring-containing aromatic diamine compound.

[0011] Dihydride compounds include one or more of the following: biphenyl dianhydrides, spirocyclic dianhydrides, aromatic / aliphatic mixed dianhydrides, heterocyclic aromatic dianhydrides, aromatic derivative dianhydrides, and alicyclic derivative dianhydrides.

[0012] In a feasible embodiment of the first aspect of this application, the diamine compounds include compounds of aromatic diamines containing a benzene ring; the dianhydrides include compounds of biphenyl dianhydrides and spirocyclic dianhydrides in a molar ratio of 1:(0.7 to 1.2).

[0013] In a feasible embodiment of the first aspect of this application, the dianhydride compounds include biphenyl dianhydride compounds, and the diamine compounds include diamines containing ether bonds and ketone groups with a molar ratio of 1:(0.7-1.2):(0.7-1.2):(0.7-1.2), diamines containing fluorinated methyl groups, diamines containing ether bonds, and diamines containing ketone groups.

[0014] In a feasible embodiment of the first aspect of this application, the toughening agent includes one or more of polyethersulfone, polyetheretherketone, polyamide-imide, and heterocyclic polyethersulfone.

[0015] In a feasible embodiment of the first aspect of this application, the toughening agent has a particle size of less than or equal to 5 μm;

[0016] In a feasible embodiment of the first aspect of this application, the thermal decomposition temperature of the toughening agent is greater than 250°C.

[0017] In a feasible embodiment of the first aspect of this application, the special resin includes a combination of cyanate ester resin and thermoplastic resin-based silicone rubber particles.

[0018] In a feasible embodiment of the first aspect of this application, the particle size of the thermoplastic resin-based silicone rubber particles is less than or equal to 10 μm.

[0019] In a feasible embodiment of the first aspect of this application, the special resin comprises cyanate ester resin and thermoplastic resin-based silicone rubber particles in a mass ratio of 1:(0.8-1.5). The special resin is prepared as follows: the cyanate ester resin and thermoplastic resin are dissolved in dichloromethane solvent to form a homogeneous solution with a solid content of not more than 40%; then silicone rubber particles are added and dispersed at a stirring speed of 800-1200 rpm for 30 minutes, followed by ultrasonic vibration for 60 minutes. Subsequently, the solvent is removed by vacuum distillation, and the mixture is washed three times and dried to obtain the special resin.

[0020] In a feasible embodiment of the first aspect of this application, the polyimide film further includes an inorganic modifier grafted with a compound containing a diamine with an ether bond structure; the inorganic modifier includes one or more of alumina, titanium dioxide, zirconium oxide, and nano-silica.

[0021] The polyimide film also includes a film-forming agent and trace additives. Optionally, the film-forming agent is mainly composed of a mixture of polyamide resin and isophorone diamine in a mass ratio of 10:1. Optionally, the additives can be defoamers and wetting agents. Optionally, the trace additives can include mixtures of polysiloxanes, Tween series, and octanoic acid polyester series in any proportion. Optionally, the trace additives can be fumed silica and organobentonite.

[0022] A second aspect of this application provides a method for preparing a polyimide film, comprising:

[0023] Preparation of polyimide resin matrix: A diamine compound is dissolved in a solvent and reacted with a dianhydride compound to obtain a polyimide resin matrix; the molar ratio of the dianhydride compound to the diamine compound is greater than 1;

[0024] Preparation of polyimide resin composition: A copolymer modifier, a toughening agent, and a special resin are mixed with a polyimide resin matrix and cured at high temperature to obtain a polyimide resin composition; the copolymer modifier includes one or more of epoxy diamine, p-aminobenzidine, p-hydroxyaniline, allyl bisphenol A, and hyperbranched siloxane; the thermal decomposition temperature of the special resin is greater than or equal to 250℃;

[0025] The polyimide resin composition is dissolved in a solvent, cast or roller-coated onto a substrate, and dried to obtain a polyimide film.

[0026] In a feasible embodiment of the second aspect of this application, in the preparation step of the polyimide resin composition, the toughening agent is a powder particle with a particle size of less than or equal to 5 μm after low-temperature ball milling; the ball milling temperature is less than or equal to 5°C.

[0027] In a feasible embodiment of the second aspect of this application, in the preparation step of the polyimide resin composition, the high-temperature curing temperature is controlled at 270-280°C and the time is maintained at 40-50 minutes.

[0028] In a feasible embodiment of the second aspect of this application, the step of preparing the polyimide resin matrix includes: adding a compound comprising a spirocyclic dianhydride and a heterocyclic aromatic dianhydride in a molar ratio of 1:(0.7-1.2) to a solution comprising a compound comprising a diamine containing an ether bond and a diamine containing an ether bond and a ketone group in at least 3 to 6 portions, mixing and reacting the mixture, with each addition occurring at intervals of 1 to 2 hours, to obtain the polyimide resin matrix.

[0029] In a feasible embodiment of the second aspect of this application, the step of preparing the polyimide resin matrix includes: dissolving a diamine compound in a solvent such as dimethylformamide, mixing it with a dianhydride compound, heating it to 130-140°C and holding it for 25-35 minutes, removing the solvent, and obtaining the polyimide resin matrix.

[0030] A third aspect of this application provides an application of a polyimide film, including a film formed by the preparation method of the polyimide film of the first aspect of this application or the polyimide film of the second aspect of this application. Attached Figure Description

[0031] Figure 1 This is a thermogravimetric analysis (TGA) graph of the polyimide resin composition in Example 1. Detailed Implementation

[0032] To make the inventive objectives, technical solutions, and beneficial technical effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the embodiments described in this specification are merely illustrative and not intended to limit the scope of this application.

[0033] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0034] In the description herein, when a composition is described as containing, comprising, or including a specific component, or when a process is described as containing, comprising, or including a specific process step, it is anticipated that the composition of this application is also primarily composed of or consisting of the said component, and that the process of this application is also primarily composed of or consisting of the said process step.

[0035] Unless otherwise expressly stated, the use of the terms “including,” “contains,” “comprising,” “containing,” and “having” should generally be interpreted as open-ended and non-restrictive.

[0036] In this description, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more.

[0037] The foregoing description of this invention is not intended to describe every disclosed embodiment or implementation. Instead, the following description provides more specific examples of exemplary embodiments. Throughout the application, guidance is provided through a series of embodiments that can be used in various combinations. The examples listed are merely representative and should not be construed as exhaustive.

[0038] The inventors discovered that the modification of polyimide films formed with polyimide resin as the main component can be achieved through the following methods: copolymerization modification, addition of toughening agents, reinforcement with inorganic fillers, composite with polymer alloys, use of film-forming agents, and optimization of trace additives.

[0039] Copolymer modifiers or toughening agents can effectively improve the flexibility and adhesive properties of polyimide resins. However, using these methods alone often leads to a performance balance problem; for example, increasing flexibility may sacrifice some thermal stability, and it is particularly difficult to improve bond strength and creep resistance under high-temperature conditions.

[0040] In view of this, the inventors have proposed a polyimide film, a preparation method and its application in this application, which aims to simultaneously improve the bonding strength and creep resistance of the polyimide film at high temperatures, and reduce the cost of the polyimide film.

[0041] The first aspect of this application provides a polyimide film, which comprises the following components in parts by weight:

[0042] 100 parts of polyimide resin matrix; and all based on 100 parts of polyimide resin matrix:

[0043] 50-80 parts of copolymer modifier; the copolymer modifier includes one or more of epoxy diamine, p-aminobenzidine, p-hydroxyaniline, allyl bisphenol A and hyperbranched siloxane;

[0044] Toughening agent 4-35 parts;

[0045] 40-100 parts of special resin; the thermal decomposition temperature of the special resin is greater than or equal to 250℃.

[0046] In this application, the copolymer modifier in the polyimide film undergoes a polymerization reaction with the polyimide resin matrix, increasing the molecular chain length and molecular weight of the polymer resin and forming a large cross-linked network. The toughening agent powder with good thermal stability and small particle size, along with the special resin, uniformly fill the large network structure formed by the polymer resin, forming a soft-hard interlocking polymer that hinders the crack propagation rate under extreme high-temperature environments. This simultaneously improves the bonding strength and creep resistance of the polyimide film formed at high temperatures, making it suitable for bonding structural components in extreme high-temperature environments such as aerospace. Furthermore, it reduces production costs while obtaining high-performance polyimide films, making it suitable for large-scale production and application.

[0047] In some embodiments, the polyimide resin matrix comprises a copolymer of a diamine compound and a dianhydride compound; the diamine compound comprises at least two of the following: compounds containing methyl diamine, compounds containing ether-bonded diamine, compounds containing ketone diamine, compounds containing ether-bonded and ketone-structured diamine, compounds containing fluorinated methyl-structured diamine, and compounds containing a benzene ring-containing aromatic diamine.

[0048] Dihydride compounds include one or more of the following: biphenyl dianhydrides, spirocyclic dianhydrides, aromatic / aliphatic mixed dianhydrides, heterocyclic aromatic dianhydrides, aromatic derivative dianhydrides, and alicyclic derivative dianhydrides.

[0049] In this application, diamine compounds refer to organic compounds containing two amino functional groups, and dianhydride compounds refer to a class of acid anhydrides consisting of two acetyl groups linked together.

[0050] The inventors have discovered that selecting a combination of at least two diamine compounds selected from compounds containing methyl diamines, ether-bonded diamines, ketone diamines, diamines containing both ether and ketone structures, diamines containing fluorinated methyl structures, and aromatic diamines containing benzene rings can effectively enhance the mechanical properties and heat resistance of polyimides. For example, the introduction of compounds containing fluorinated methyl diamines and diamines with ketone structures not only improves the chemical stability of the polymer but also enhances its heat resistance.

[0051] In some embodiments, the diamine compounds include compounds of aromatic diamines containing a benzene ring; the dianhydrides include compounds of biphenyl dianhydrides and spirocyclic dianhydrides in a molar ratio of 1:(0.7 to 1.2).

[0052] In some embodiments, the dianhydride compounds include biphenyl dianhydride compounds, and the diamine compounds include diamines containing ether bonds and ketone groups in a molar ratio of 1:(0.7-1.2):(0.7-1.2):(0.7-1.2), diamines containing fluorinated methyl groups, diamines containing ether bonds, and diamines containing ketone groups.

[0053] Furthermore, the inventors discovered that by selecting specific types of diamine compounds and dianhydride compounds for combination, polyimide films with better adhesion and heat resistance at high temperatures can be obtained, especially the aforementioned combinations of diamine compounds and dianhydride compounds are more ideal. For example, when biphenyl dianhydrides are selected, compounds containing ether bonds and ketone groups, compounds containing fluorinated methyl groups and ether bonds, and compounds containing ketone groups will all undergo polymerization reactions with the dianhydride. Among them, compounds containing ketone groups react first, followed by compounds containing ether bonds and ketone groups, and then compounds containing fluorinated methyl groups, forming an orderly and large cross-linked network layer by layer, thereby improving the high-temperature performance of the polyimide film.

[0054] In some embodiments, the toughening agent includes one or more of polyethersulfone, polyetheretherketone, polyamide-imide, and heterocyclic polyethersulfone;

[0055] Optionally, the toughening agent has a particle size of less than or equal to 5 μm;

[0056] Optionally, the toughening agent has a thermal decomposition temperature greater than 250°C.

[0057] The type and particle size of toughening agents also affect the high-temperature performance of the resulting polyimide film. In particular, the aforementioned types of polyethersulfone toughening agents have a thermal decomposition temperature greater than 250°C. After low-temperature ball milling, they can be formed into ultrafine powders with a particle size of less than or equal to 5 μm, which improves their dispersibility in polyimide resin and enhances the toughness and fracture resistance of polyimide resin at high temperatures.

[0058] In some embodiments, the specialty resin includes a combination of cyanate ester resins and thermoplastic resin-based silicone rubber particles; optionally, the particle size of the thermoplastic resin-based silicone rubber particles is less than or equal to 10 μm.

[0059] This application primarily aims to improve the performance of polyimide films at high temperatures. The selected specialty resins all have thermal decomposition temperatures exceeding 250°C. In particular, the aforementioned cyanate ester resins and thermoplastic resin-based silicone rubber particles not only provide additional mechanical strength but also improve the resin's processability and abrasion resistance. This design allows polyimide to maintain its performance in more demanding environments, such as applications involving high abrasion and high temperatures.

[0060] Optionally, the specialty resin includes cyanate ester resin and thermoplastic resin-based silicone rubber particles in a mass ratio of 1:(0.8-1.5). The preparation method of the specialty resin is as follows: the cyanate ester resin and thermoplastic resin are dissolved in dichloromethane solvent to form a homogeneous solution with a solid content of no more than 40%; then silicone rubber particles are added and dispersed at a stirring speed of 800-1200 rpm for 30 minutes, followed by ultrasonic vibration for 60 minutes. Subsequently, the solvent is removed by vacuum distillation, and the solution is washed three times and dried to obtain the specialty resin.

[0061] In this application, inorganic modifiers, film-forming agents, defoamers, and wetting agents can also be added to the polyimide film. The inventors have also discovered that the addition of inorganic modifiers grafted with diamine compounds containing ether bonds significantly improves the high-temperature performance of the polyimide resin compared to unmodified inorganic modifiers.

[0062] Film-forming agents and trace additives such as defoamers and wetting agents can optimize the flowability and surface properties of the resin, ensuring the excellent application performance of high heat-resistant polyimide resin structural films in high-temperature environments, and enhancing the efficiency of the film-forming process and the uniformity of the film layer.

[0063] In some embodiments, the polyimide film also includes an inorganic modifier grafted with a compound containing a diamine with an ether bond structure; the inorganic modifier includes one or more of alumina, titanium dioxide, zirconium oxide and nano-silica.

[0064] The polyimide film also includes a film-forming agent and trace additives. Optionally, the film-forming agent is mainly composed of a mixture of polyamide resin and isophorone diamine in a mass ratio of 10:1. Optionally, the additives can be defoamers and wetting agents. Optionally, the trace additives can include mixtures of polysiloxanes, Tween series, and octanoic acid polyester series in any proportion. Optionally, the trace additives can be fumed silica and organobentonite.

[0065] The second aspect of this application provides a method for preparing a polyimide film, comprising:

[0066] Preparation of polyimide resin matrix: Diamine compounds are dissolved in a solvent and reacted with dianhydride compounds to obtain polyimide resin matrix; the molar ratio of dianhydride compounds to diamine compounds is greater than 1;

[0067] Preparation of polyimide resin composition: A copolymer modifier, a toughening agent, and a special resin are mixed with a polyimide resin matrix and cured at high temperature to obtain a polyimide resin composition; the copolymer modifier includes one or more of epoxy diamine, p-aminobenzidine, p-hydroxyaniline, allyl bisphenol A, and hyperbranched siloxane; the thermal decomposition temperature of the special resin is greater than or equal to 250℃;

[0068] The polyimide resin composition is dissolved in a solvent, cast or roller-coated onto a substrate, and dried to obtain a polyimide film.

[0069] In the preparation method of the polyimide film of this application, a diamine compound is dissolved in a solvent and reacted with an excess of a dianhydride compound to obtain a polyimide resin matrix with an excess of dianhydride compound. Then, a copolymer modifier is added. The copolymer modifier reacts with the dianhydride compound to expand the cross-linking network of the polyimide resin matrix. Combined with a toughening agent powder with good thermal stability and small particle size, and a special resin, these components are uniformly filled into the large network structure formed by the polymer resin, forming a soft-hard interlocking polymer that inhibits crack propagation speed under extreme high-temperature environments. This simultaneously improves the adhesive strength and creep resistance of the resulting polyimide film at high temperatures. Furthermore, this application reduces production costs while obtaining a high-performance polyimide film, making it suitable for large-scale production and application.

[0070] The inventors discovered that the copolymer modifier needs to be added after the diamine compound and an excess of dianhydride compound have formed the polyimide resin matrix, and the dianhydride compound should be in excess of the diamine compound, for example, added at 80% of the mass of the polyimide resin matrix. This can improve the mechanical strength, chemical stability, and adhesive strength of the polyimide resin. If it is not added separately, it will actually reduce the adhesive performance of the polyimide film at high temperatures.

[0071] In some embodiments, in the preparation steps of the polyimide resin composition, the toughening agent is a powder particle with a particle size of less than or equal to 5 μm after low-temperature ball milling; the ball milling temperature is less than or equal to 5°C.

[0072] Before being added to polyimide resin, the toughening agent described in this application needs to be ball-milled at a low temperature to obtain powder particles with a particle size of less than or equal to 5 μm. The ball-milling temperature must be less than or equal to 5°C; otherwise, the toughening agent particles will easily agglomerate, making it difficult to ball-mill into a uniform ultrafine powder, resulting in poor filling effect. After treatment with the toughening agent of this application, the toughness and fracture resistance of polyimide resin can be effectively improved.

[0073] In some embodiments, during the preparation of the polyimide resin composition, the curing temperature is controlled at 270-280°C, and the curing time is maintained at 40-50 minutes.

[0074] In some embodiments, the preparation of the polyimide resin matrix includes: adding a compound comprising a spirocyclic dianhydride and a heterocyclic aromatic dianhydride in a molar ratio of 1:(0.7-1.2) to a solution comprising a compound comprising a diamine containing an ether bond and a diamine containing an ether bond and a ketone group in at least 3 to 6 portions, mixing and reacting the mixture with each addition occurring at intervals of 1 to 2 hours, to obtain the polyimide resin matrix.

[0075] The inventors discovered that adding the above-mentioned dianhydride composition in at least 3 to 6 portions, with an interval of 1 to 2 hours between each addition, can effectively reduce the generation of byproducts and have a significant impact on the high-temperature performance of polyamide resins.

[0076] In some embodiments, the preparation of the polyimide resin matrix includes: dissolving a diamine compound in a solvent such as dimethylformamide, mixing it with a dianhydride compound, heating it to 130-140°C and holding it for 25-35 minutes, removing the solvent to obtain the polyimide resin matrix.

[0077] The third aspect of this application provides an application of a polyimide film, including the polyimide film of the first aspect of this application or the polyimide film of the second aspect of this application prepared by the same method.

[0078] The polyimide resin structural film designed in this application overcomes the performance limitations of traditional polyimide resins in extreme high-temperature environments by introducing various modifiers and reinforcing materials through prepolymerization technology and mechanical thermal blending. This structural film not only possesses superior high-temperature adhesive strength and creep resistance, meeting the stringent requirements of industries such as aerospace for structural films under extreme conditions, but also reduces the production cost of polyimide films.

[0079] Examples

[0080] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0081] Example 1

[0082] The preparation of a high heat-resistant polyimide resin composition comprises 50g N,N'-dimethyl-1,6-hexanediamine, 50g dibenzylethylenediamine, 90g biphenyl dianhydride, 70g spirocyclopentadiene dianhydride, 160g copolymer modifier p-aminobenzidine, 160g heterocyclic polyethersulfone ultrafine powder toughening agent with an average particle size of less than or equal to 5μm ball-milled below 0℃, 30g high-molecular-weight special resin (cyanate ester resin and thermoplastic resin-based silicone rubber in a mass ratio of 1:1), 5g alumina grafted with ether diamine (grafting amount 0.5wt%, 4-methoxy-o-phenylenediamine) as filler, and 15g polyamide resin and isophorone diamine mixture (mass ratio of 1:10) as film-forming agent.

[0083] Preparation of a high heat-resistant polyimide film:

[0084] Two diamines, N,N'-dimethyl-1,6-hexanediamine and dibenzylethylenediamine, were mixed and dissolved in dimethylformamide solvent. This mixture was then combined with biphenyl dianhydride and spirocyclopentadiene dianhydride, heated to 130°C and maintained for 30 minutes. The solvent was then removed, and a polyimide resin matrix was formed through a thermal reaction.

[0085] Add the copolymer modifier p-aminobenzidine, the toughening agent of heterocyclic polyethersulfone ultrafine powder with an average particle size of less than or equal to 5 μm milled at 0℃, the polymer special resin (cyanate ester resin and thermoplastic resin-based silicone rubber), 5g of alumina inorganic modifier grafted with ether diamine as filler, and 15g of a mixture of polyamide resin and isophorone diamine (mass ratio of 1:10) as film-forming agent to the polyimide resin matrix. Curing is carried out at a high temperature of 280℃ for 40-50 minutes to complete the polymerization reaction and obtain the above polyimide resin composition.

[0086] The polyimide resin composition is dissolved in a solvent, cast onto a substrate, and dried to obtain a polyimide film.

[0087] Testing revealed that the prepared polyimide resin composition exhibits a shear strength of 27 MPa at -60°C, 51 MPa at room temperature, and nearly 23 MPa at 200°C. Thermogravimetric analysis showed a significant thermogravimetric temperature (TGA) of 525°C, where the TGA is defined as the temperature at which a 5 wt% mass loss is detected. This demonstrates that the polyimide resin composition of this application not only possesses good adhesive strength at low and room temperatures but also exhibits excellent high-temperature performance, particularly in terms of adhesive properties and thermal stability. Peel strength testing was performed on the obtained polyimide film, measuring the peel strength between the frosted aluminum surface and the film. Furthermore, the polyimide film of this application reduces the mass percentage of the polyimide resin matrix in the film, lowering the production cost while maintaining excellent performance, especially in high-temperature performance.

[0088] Example 2

[0089] The main difference between Example 2 and Example 1 is that, in the preparation of the high heat-resistant polyimide resin composition, the dianhydride compounds used are alicyclic dianhydrides (a spirocyclic dianhydride) and cyclobutanetetracarboxylic dianhydrides (a heterocyclic aromatic dianhydride) in a molar ratio of 1:1 used in the polyimide resin matrix. The diamines are 1,3-bis(3-aminophenoxy)benzene with an ether bond structure and isophorone ethylenediamine in a molar ratio of 1:1, replacing 50g of N,N'-dimethyl-1,6-hexanediamine and 50g of 4,4'-difluorodiphenylamine in Example 1. The dianhydrides are added in four portions, with an interval of 1 hour between each addition.

[0090] Example 3

[0091] The main difference between Example 3 and Example 1 is that, in the preparation of the high heat-resistant polyimide resin composition, the dianhydride used in the polyimide resin matrix is ​​entirely biphenyl dianhydride, and the diamine composition is N-BOC-1,3-propanediamine with ether and ketone groups in a molar ratio of 1:1:1:1, 2,3-diaminotrifluorotoluene with fluorinated methyl groups, 4-ethoxyphenyl-1,2-diamine with ether groups, and 2,6-diaminoanthraquinone with ketone groups. The total molar amount of each dianhydride and diamine is the same as in Example 1. The dianhydride is added in 4 portions, with an interval of 1 hour between each addition.

[0092] Example 4

[0093] The main difference between Example 4 and Example 1 is that, in the preparation of the high heat-resistant polyimide resin composition, an equal mass of toughening agent made by mixing modified epoxy polybenzimidazole resin and thermoplastic polyphenylene ether resin in a mass ratio of 2:1 was used instead of the heterocyclic polyethersulfone ultrafine powder toughening agent with an average particle size of less than or equal to 5 μm that was ball-milled at 0°C in Example 1.

[0094] Example 5

[0095] The main difference between Example 5 and Example 1 is that, in the preparation of the high heat-resistant polyimide resin composition, the toughening agent is a heterocyclic polyethersulfone powder ball-milled at room temperature (22°C to 25°C) for 2 hours, with an average particle size of 20 μm, replacing the heterocyclic polyethersulfone ultrafine powder toughening agent with an average particle size of less than or equal to 5 μm ball-milled at 0°C in Example 1.

[0096] Example 6

[0097] The main difference between Example 6 and Example 1 is that, in the preparation of the high heat-resistant polyimide resin composition, the special resin used is a phosphorus-containing phenolic resin, which replaces the special resin made by mixing cyanate ester resin and thermoplastic resin-based silicone rubber in Example 1.

[0098] Example 7

[0099] The main difference between Example 7 and Example 1 is that, in the preparation of the high heat-resistant polyimide resin composition, unmodified silica was used as the inorganic modifier instead of the alumina inorganic modifier grafted with ether diamine in Example 1 as the filler.

[0100] Example 8

[0101] The main difference between Example 8 and Example 1 is that, in the preparation of the high heat-resistant polyimide resin composition, a film-forming agent consisting of a 1:1 mass ratio of 4,4'-diaminodiphenyl sulfide and 2,4-diaminodiphenyl sulfide is used instead of the 1:10 mass ratio mixture of polyamide resin and isophorone diamine in Example 1.

[0102] Example 9

[0103] The main difference between Example 9 and Example 1 is that 2.5g of a mixture of trace additives, fumed silica and organobentonite, was introduced during the curing stage and used at a mass ratio of 3:1.

[0104] Example 10

[0105] The main difference between Example 10 and Example 1 is that no ether-based diamine grafted modified alumina inorganic modifier or a mixture of polyamide resin and isophorone diamine film-forming agent was added during the preparation of the high heat-resistant polyimide resin composition.

[0106] Example 11

[0107] The main difference between Example 11 and Example 1 is that the film-forming technology is different in the preparation process of the high heat-resistant polyimide film. Specifically, a three-roller coating film-forming machine is used for film formation, and the film-forming temperature is set to 80°C.

[0108] Comparative Example 1

[0109] The main difference between Comparative Example 1 and Example 1 is that the copolymer modifier p-aminobenzidine was not added.

[0110] Comparative Example 2

[0111] The main difference between Comparative Example 2 and Example 1 is that no heterocyclic polyethersulfone ultrafine powder toughening agent with an average particle size of less than or equal to 5 μm was added.

[0112] Comparative Example 3

[0113] The main difference between Comparative Example 3 and Example 1 is that no special resin cyanate ester resin and thermoplastic resin-based silicone rubber were added.

[0114] Comparative Example 4

[0115] The main difference between Comparative Example 4 and Example 1 is that the special resin used is bisphenol A type epoxy resin.

[0116] Test methods

[0117] Test method for shear strength of resin compositions: GB 7124-86.

[0118] Test method for thermogravimetric analysis of resin compositions: GB / T 27761—2011.

[0119] Test method for peel strength of polyimide film: GB / T 2791-1995.

[0120] The test results are shown in Table 1 below.

[0121] Table 1:

[0122]

[0123]

[0124] The above embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A polyimide adhesive film characterized by comprising: The polyimide adhesive film comprises components in the following proportions by weight: 100 parts of a polyimide resin matrix; and, based on 100 parts of the polyimide resin matrix, 50-80 parts of a copolymerization modifier, 4-35 parts of a toughening agent, and 40-100 parts of a special resin, wherein the polyimide resin matrix comprises a copolymer of a diamine compound and a dianhydride compound, the molar ratio of the dianhydride compound to the diamine compound is greater than 1, the diamine compound comprises at least two of a methyl-containing diamine compound, an ether-bond-containing diamine compound, a ketone-group-containing diamine compound, an ether-bond-and-ketone-group-containing diamine compound, a fluorinated-methyl-group-containing diamine compound, and a benzene-ring-containing aromatic diamine compound, and the dianhydride compound comprises one or more of a biphenyl dianhydride compound, a spirocyclic dianhydride compound, an aromatic / aliphatic mixed dianhydride compound, a heterocyclic aromatic dianhydride compound, and an alicyclic derivative dianhydride compound; The copolymerization modifier comprises one or more of p-aminobenzidine and p-hydroxyaniline; The toughening agent comprises one or more of an epoxy-based polybenzimidazole resin, a thermoplastic polyphenyl ether resin, and a heterocyclic polyether sulfone; The special resin comprises a mixture of a phosphorus-containing phenolic resin or a cyanate ester resin and a thermoplastic resin-based silicone rubber particle, and the thermal decomposition temperature of the special resin is greater than or equal to 250°C.

2. The polyimide adhesive film according to claim 1, characterized by The diamine compound comprises a benzene-ring-containing aromatic diamine compound, and the dianhydride compound comprises a biphenyl dianhydride compound and a spirocyclic dianhydride compound in a molar ratio of 1:(0.7-1.2); The dianhydride compound comprises a biphenyl dianhydride compound, and the diamine compound comprises a ketone-group-and-ether-bond-containing diamine compound, a fluorinated-methyl-group-containing diamine compound, and an ether-bond-containing diamine compound in a molar ratio of 1:(0.7-1.2):(0.7-1.2):(0.7-1.2). The particle size of the toughening agent is less than or equal to 5 μm.

3. The polyimide adhesive film according to claim 1, wherein Optionally, the thermal decomposition temperature of the toughening agent is greater than 250°C. The particle size of the thermoplastic resin-based silicone rubber particle is less than or equal to 10 μm.

4. The polyimide adhesive film of claim 1, wherein The polyimide adhesive film further comprises an inorganic modifier grafted with an ether-bond-containing diamine compound, and the inorganic modifier comprises one or more of aluminum oxide, titanium white, zirconium oxide, and nano-silicon dioxide; and / or 5. The polyimide adhesive film of claim 1, wherein The polyimide adhesive film further comprises one or more of a film-forming agent, a defoaming agent, and a wetting agent. The preparation of the polyimide resin matrix comprises dissolving a diamine compound in a solvent and mixing and reacting with a dianhydride compound to obtain the polyimide resin matrix, wherein the molar ratio of the dianhydride compound to the diamine compound is greater than 1; 6. A method for producing the polyimide adhesive film according to any one of claims 1 to 5, characterized by, The preparation of the polyimide resin composition comprises mixing a copolymerization modifier, a toughening agent, and a special resin with a polyimide resin matrix, and high-temperature curing and reacting to obtain the polyimide resin composition, wherein the copolymerization modifier comprises one or more of p-aminobenzidine and p-hydroxyaniline, and the thermal decomposition temperature of the special resin is greater than or equal to 250°C. ​ ​ The polyimide resin composition is dissolved in a solvent, cast or roll-coated onto a substrate, and dried to obtain a polyimide adhesive film.

7. The method for preparing the polyimide film according to claim 6, characterized in that, In the step of preparing the polyimide resin composition, the toughening agent is a powder particle with a particle size of less than or equal to 5 μm after low-temperature ball milling; and the ball milling temperature is less than or equal to 5 ℃.

8. The method for preparing the polyimide film according to claim 6, characterized in that, The step of preparing the polyimide resin substrate comprises: mixing and reacting, at least in 3-6 times, a compound comprising a spiro compound dianhydride and a heterocyclic aromatic compound dianhydride with a molar ratio of 1: (0.7-1.2) into a solution of a compound comprising an ether bond-containing diamine, an ether bond-containing and ketone group-containing diamine, with an interval of 1-2 hours for each time, to obtain the polyimide resin substrate.

9. Use of a polyimide adhesive film, characterized in that An adhesive film formed by the method for preparing the polyimide adhesive film according to any one of claims 1-5 or the polyimide adhesive film according to any one of claims 6-8.

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