Polyphenyl ether hybrid polyimide adhesive film and copper-clad plate

Abstract

In order to solve the problem that an existing polyimide adhesive film is difficult to meet the requirement for use in a high-temperature and high-frequency application environment, the invention provides a polyphenyl ether hybrid polyimide adhesive film and a copper-clad laminate, and the polyphenyl ether hybrid polyimide adhesive film comprises the following components in parts by weight: 40-70 parts of carboxyl-terminated polyphenyl ether hybrid polyimide, 15-30 parts of polyphenyl ether filler, 1-5 parts of antioxidant, 1-5 parts of coupling agent and 1-5 parts of coupling agent. 5 to 15 parts of an epoxy group branched cross-linking agent; wherein the polyphenyl ether filler is subjected to hydroxyl activation treatment; the epoxy group branched cross-linking agent is multifunctional epoxy resin with a branched chain end group being an epoxy group. The polyphenyl ether hybridized polyimide adhesive film provided by the invention is suitable for being used as a bonding layer or a base material of a multilayer flexible printed circuit (MLFPC), and can effectively solve the problem of debonding between circuit board layers and between a printed circuit and the base material under the condition of dynamic impact load during high-frequency operation (high thermal shock) of the circuit board and vehicle operation; the service life of the circuit board is prolonged; and the dynamic environment deterioration resistance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyimide film materials, and in particular relates to a polyphenylene ether hybrid polyimide film and a copper clad laminate. Background Art

[0002] With the demand for power distribution, automotive electronics, and intelligent technology in new energy vehicles, the proportion of electronic components and integrated modules in the assembly process is increasing. The complex and harsh operating environment of vehicles and the long service life have prompted PCB technology to develop in the direction of high speed, high frequency, high density interconnection (HDI) and small size. Multilayer flexible circuit boards (MLFPC) have become the first choice for the packaging and molding technology of the new generation of automotive circuit boards due to their excellent anti-bending, lightweight, reliability, safety, and high degree of automation.

[0003] Polyimide has excellent flexibility, heat resistance and dielectric properties, and is often used as a base material for multi-layer flexible circuit boards. In some application environments, the material itself has higher dielectric properties and heat resistance requirements, such as some locations that require soldering, or used in high-frequency signal transmission devices, or some extreme application environments. Pure polyimide is difficult to meet its dielectric properties and heat resistance requirements. There are many existing solutions. One is blending modification, which is to modify the material by blending polyimide with other inorganic or organic substances and utilizing the complementarity and synergy between polymers or inorganic substances; for example, PI / inorganic nanoparticle blending can increase its thermal decomposition temperature and electrical strength; the second is copolymerization modification, which is to add a third monomer to form two anhydrides and one amine or two amines and one anhydride during synthesis. The properties of the resulting polymer will change greatly. At the same time, by changing the type of monomers for synthesizing polyimide and adjusting the ratio of monomers, the performance of polyimide can be improved; the third is structural modification, based on molecular design ideas, in PI Flexible groups such as ether bonds, keto bonds, alkyl groups, etc. are introduced into the macromolecular chain, large side groups such as phenyl, n-butyl, trifluoromethyl, etc. are introduced into the side chain, and asymmetric or twisted non-coplanar structures are designed and synthesized.

[0004] Among them, regarding the first blending and compounding method, there is an existing method of improving the dielectric properties of polyimide by blending polyphenylene ether in polyimide, but this method will correspondingly reduce the heat resistance and hygroscopicity of the material itself. Summary of the invention

[0005] In view of the problem that the existing polyimide film is difficult to be used in high-temperature and high-frequency application environments, the present invention provides a polyphenylene ether hybrid polyimide film and a copper clad laminate.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows: The present invention provides a polyphenylene ether hybrid polyimide adhesive film, comprising the following components by weight: 40-70 parts of carboxyl-terminated polyphenylene ether hybrid polyimide, 15-30 parts of polyphenylene ether filler, and 5-15 parts of epoxy branched crosslinking agent; Wherein, the polyphenylene ether filler is treated with hydroxyl activation; The epoxy branched crosslinking agent is a multifunctional epoxy resin having a branched terminal group being an epoxy group.

[0007] Optionally, the polyphenylene ether hybrid polyimide adhesive film comprises the following components by weight: 60-70 parts of carboxyl-terminated polyphenylene ether hybrid polyimide, 20-30 parts of polyphenylene ether filler, and 5-10 parts of epoxy branched crosslinking agent.

[0008] Optionally, the hydroxyl activation treatment method of the polyphenylene ether filler is: The polyphenylene ether is dissolved in a solvent, and liquid bromine is added to carry out a bromination reaction to obtain a bromomethylated polyphenylene ether solution, and the bromomethylated polyphenylene ether is obtained after precipitation and drying; the bromomethylated polyphenylene ether is immersed in a sodium hydroxide solution, and reacted at a constant temperature of 80°C to 95°C to obtain a hydroxylated polyphenylene ether solution, and the polyphenylene ether filler is obtained after washing and drying.

[0009] Optionally, the epoxy branched crosslinking agent is selected from 2,2'-[[2-ethyl-2-[(oxiranylmethoxy)methyl]-1,3-dipropyl]bis(oxymethylene)]bisoxirane.

[0010] Optionally, the structure of the carboxyl-terminated polyphenylene ether hybrid polyimide is shown in Structural Formula 1: Structural formula 1 Wherein, m is selected from an integer of 5 to 30, R' is selected from a polyphenylene ether segment, and R is selected from a polyimide segment.

[0011] Optionally, the R is selected from the segment shown in structural formula 2: Structural formula 2 Wherein, n is selected from an integer ranging from 5 to 90.

[0012] Optionally, the R' is selected from the segment shown in structural formula 3: Structural formula 3 Wherein, I is selected from an integer of 3 to 10.

[0013] Optionally, the R' is selected from the segment shown in structural formula 4: Structural formula 4 Wherein, d is selected from an integer ranging from 8 to 25.

[0014] Optionally, the molecular weight of the polyphenylene ether hybrid polyimide is 10,000-400,000.

[0015] On the other hand, the present invention provides a flexible circuit board, comprising a laminated ketone-coated film and the polyphenylene ether hybrid polyimide adhesive film as described above.

[0016] According to the polyphenylene ether hybrid polyimide adhesive film provided by the present invention, a multifunctional epoxy resin containing a branched end group as an epoxy group is selected as an epoxy branched crosslinking agent to realize the crosslinking networking (curing) of the matrix unit structure; at the same time, a polyphenylene ether filler containing a reactive site (-OH) is introduced in situ, and the hydroxyl groups on the polyphenylene ether filler can form a three-dimensional network crosslink with the multifunctional epoxy resin containing a branched end group as an epoxy group, thereby further increasing the crosslinking depth, realizing uniform dispersion of the polyphenylene ether filler in the resin network, improving the compatibility between the polyphenylene ether and the resin network, and constructing a homogenized "island-chain" resin network structure. The prepared polyphenylene ether hybrid polyimide adhesive film has excellent heat resistance, high peel strength and flexibility, extremely low dielectric constant and dielectric loss, extremely low moisture absorption rate and other properties. It is suitable for use as the bonding layer or substrate of multi-layer MLFPC (multi-layer flexible circuit board). It can effectively solve the debonding problem between circuit board layers and between printed circuits and substrates under high-frequency operation (generating high thermal shock) and dynamic impact load conditions during vehicle operation, thereby improving the service life of circuit boards and their ability to resist dynamic environmental deterioration. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] An embodiment of the present invention provides a polyphenylene ether hybrid polyimide adhesive film, comprising the following components by weight: 40-70 parts of carboxyl-terminated polyphenylene ether hybrid polyimide, 10-30 parts of polyphenylene ether filler, and 5-15 parts of epoxy branched crosslinking agent; Wherein, the polyphenylene ether filler is treated with hydroxyl activation; The epoxy branched crosslinking agent is a multifunctional epoxy resin having a branched terminal group being an epoxy group.

[0019] According to the polyphenylene ether hybrid polyimide adhesive film provided by the present invention, a multifunctional epoxy resin containing a branched end group as an epoxy group is selected as an epoxy branched crosslinking agent to realize the crosslinking networking (curing) of the matrix unit structure; at the same time, a polyphenylene ether filler containing a reactive site (-OH) is introduced in situ, and the hydroxyl groups on the polyphenylene ether filler can form a three-dimensional network crosslink with the multifunctional epoxy resin containing a branched end group as an epoxy group, thereby further increasing the crosslinking depth, realizing uniform dispersion of the polyphenylene ether filler in the resin network, improving the compatibility between the polyphenylene ether and the resin network, and constructing a homogenized "island-chain" resin network structure. The prepared polyphenylene ether hybrid polyimide adhesive film has excellent heat resistance, high peel strength and flexibility, extremely low dielectric constant and dielectric loss, extremely low moisture absorption rate and other properties. It is suitable for use as the bonding layer or substrate of multi-layer MLFPC (multi-layer flexible circuit board). It can effectively solve the debonding problem between circuit board layers and between printed circuits and substrates under high-frequency operation (generating high thermal shock) and dynamic impact load conditions during vehicle operation, thereby improving the service life of the circuit board and its ability to resist dynamic environmental deterioration.

[0020] In some preferred embodiments, the polyphenylene ether hybrid polyimide adhesive film comprises the following weight components: 60-70 parts of carboxyl-terminated polyphenylene ether hybrid polyimide, 20-30 parts of polyphenylene ether filler, and 5-10 parts of epoxy branched crosslinking agent.

[0021] In some embodiments, the hydroxyl activation treatment method of the polyphenylene ether filler is: The polyphenylene ether is dissolved in a solvent, and liquid bromine is added to carry out a bromination reaction to obtain a bromomethylated polyphenylene ether solution, and the bromomethylated polyphenylene ether is obtained after precipitation and drying; the bromomethylated polyphenylene ether is immersed in a sodium hydroxide solution, and reacted at a constant temperature of 80°C to 95°C to obtain a hydroxylated polyphenylene ether solution, and the polyphenylene ether filler is obtained after washing and drying.

[0022] By subjecting the polyphenylene ether filler to hydroxyl activation treatment, the cross-linking sites between the polyphenylene ether filler and the carboxyl-terminated polyphenylene ether hybrid polyimide can be increased, thereby achieving uniform dispersion of the polyphenylene ether filler. The polyphenylene ether filler can be riveted or bridged into the cured network structure in the form of grafting or block reaction, thereby constructing a phase-uniform "island-chain" chemically compatible structural network, giving the film better properties such as temperature resistance, bonding strength, low dielectric, and low moisture absorption.

[0023] In some embodiments, the epoxy-branched crosslinking agent is selected from 2,2′-[[2-ethyl-2-[(oxiranylmethoxy)methyl]-1,3-dipropyl]bis(oxymethylene)]bisoxirane.

[0024] The cross-linking and curing of the polyimide system is achieved by utilizing the reaction between epoxy groups and carboxyl groups (-COOH) and hydroxyl groups. At the same time, its branched structure is conducive to the construction of a tough network structure resin with a flexible ester bonded polyphenylene ether block, thereby improving the flexibility, temperature resistance, low dielectric properties and other properties of the film.

[0025] In some embodiments, the structure of the carboxyl-terminated polyphenylene ether hybrid polyimide is shown in Structural Formula 1: Structural formula 1 Wherein, m is selected from an integer of 5 to 30, R' is selected from a polyphenylene ether segment, and R is selected from a polyimide segment: In the polyphenylene ether hybrid polyimide shown in structural formula 1, polyphenylene ether is introduced into the molecular chain of polyimide in a block manner by means of polycondensation reaction to form a polyphenylene ether and polyimide block copolymer. Compared with the existing blending method, the polyphenylene ether hybrid polyimide provided by the present invention realizes the block copolymerization of polyphenylene ether and polyimide at the molecular level to form a hybrid segment, effectively reducing the arrangement density of polar dipole groups inside the molecular chain, thereby reducing the dielectric constant, dielectric loss and water absorption of the polyimide / polyphenylene ether alloy, and further optimizing the dielectric properties and moisture and heat resistance of the polyimide / polyphenylene ether alloy to make it suitable for the packaging field of electronic products related to high-speed and high-frequency operating environments. In some embodiments, the R is selected from a linear polyimide segment.

[0026] In some embodiments, the R is selected from the segment shown in Structural Formula 2: Structural formula 2 Wherein, n is selected from an integer ranging from 5 to 90.

[0027] In some embodiments, the R' is selected from the segment shown in Structural Formula 3: Structural formula 3 Wherein, I is selected from an integer of 3 to 10; In other embodiments, the R' is selected from the segment shown in structural formula 4: Structural formula 4 Wherein, d is selected from an integer ranging from 8 to 25.

[0028] In some embodiments, the molecular weight of the polyphenylene ether hybrid polyimide is 10,000-200,000.

[0029] In some embodiments, the polyphenylene ether hybrid polyimide is obtained by the following steps: 1) carboxyl-terminated polyisoimide and hydroxyl-terminated polyphenylene ether are polymerized by esterification to obtain polyphenylene ether hybrid polyisoimide; 2) polyphenylene ether hybrid polyisoimide is obtained by isomerization reaction.

[0030] In some embodiments, the carboxyl-terminated polyisoimide is selected from the compound shown in Structural Formula 5: Structural formula 5 Wherein, n is selected from an integer ranging from 5 to 90.

[0031] In some embodiments, the hydroxylated polyphenylene ether is selected from the compound shown in Structural Formula 6: HO-R'-OH Structural formula 6 Wherein R' is selected from the segment shown in Structural Formula 3 or the segment shown in Structural Formula 4: Structural formula 3 Wherein, I is selected from an integer of 3 to 10; Structural formula 4 Wherein, d is selected from an integer ranging from 8 to 25.

[0032] In some embodiments, the molecular weight of the carboxyl-terminated polyphenylene ether hybrid polyimide is 100,000-400,000.

[0033] In some embodiments, the method for preparing the carboxyl-terminated polyphenylene ether hybrid polyimide comprises the following steps: S1. Preparation of carboxyl-terminated polyisoimide: S11: polymerizing an aminocarboxylic acid end-capping agent, a dibasic acid anhydride and a diamine to obtain a carboxyl-terminated polyamic acid; S12: subjecting the carboxyl-terminated polyamic acid to an isoimide cyclization reaction to obtain a carboxyl-terminated polyisoimide; S2. Preparation of polyphenylene ether hybrid polyimide: S21: subjecting carboxyl-terminated polyisoimide to esterification polycondensation reaction with hydroxyl-terminated polyphenylene ether to obtain polyphenylene ether hybrid polyisoimide; S22: isomerizing polyphenylene ether hybrid polyisoimide to obtain polyphenylene ether hybrid polyimide.

[0034] Specifically, the reaction principle process is as follows: In the above-mentioned preparation method, the carboxyl-terminated polyisoimide is self-made, and an amidation polymerization reaction is carried out with an aminocarboxylic acid end-capping agent and a dibasic acid anhydride and a diamine to obtain a carboxyl-terminated polyamic acid; and the carboxyl-terminated polyamic acid is subjected to an isoimide cyclization reaction to obtain a carboxyl-terminated polyisoimide; on the basis of the prepared carboxyl-terminated polyisoimide, it is subjected to an esterification polycondensation reaction with a hydroxylated polyphenylene ether to achieve block chemical bonding and dispersion of the polyphenylene ether in the polyisoimide segment; and then a polyphenylene ether hybrid polyisoimide is obtained by an isomerization reaction of the polyphenylene ether hybrid polyisoimide. The hybrid polyimide not only has better dielectric properties and moisture and heat resistance, but also has excellent temperature resistance.

[0035] In some embodiments, in the polymerization reaction of aminocarboxylic acid end-capping agent, dibasic acid anhydride and diamine in step S11, the aminocarboxylic acid end-capping agent is selected from 3,5-diaminobenzoic acid (DABA), the dibasic acid anhydride is selected from phenyl dibasic acid anhydride, and the diamine is selected from phenyl diamine.

[0036] In some embodiments, the dibasic acid anhydride is selected from one or more of 3,3,4,4-biphenyltetracarboxylic dianhydride and 4,4'-biphenyl ether tetracarboxylic dianhydride, preferably 4,4'-biphenyl ether tetracarboxylic dianhydride.

[0037] In some embodiments, the diamine is selected from one or more of 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, or 4,4'-diamino-3,3'-dimethylbiphenyl, preferably 4,4'-diaminodiphenyl ether.

[0038] In some embodiments, the molar ratio of the dibasic acid anhydride to the diamine is 1:1.

[0039] In some embodiments, the molar ratio of the dibasic acid anhydride to the 3,5-diaminobenzoic acid (DABA) is 1:(0.01-0.1).

[0040] The polymerization degree of the polyamic acid can be controlled and the molecular weight of the carboxyl-terminated polyisoimide can be adjusted by controlling the added molar ratio of the 3,5-diaminobenzoic acid (DABA) and the dibasic acid anhydride. In some embodiments, in the polymerization reaction of the aminocarboxylic acid end-capping agent, the dibasic acid anhydride and the diamine in step S11, the reaction temperature is -10 to 20°C, and the reaction time is determined by measuring the actual acid value of the reaction system. When the actual acid value of the system reaches the theoretical acid value, the reaction is completed. The determination method adopts potassium hydroxide titration, and the acid value is expressed in mgKOH / g.

[0041] In some embodiments, in the step S12, a first catalyst is added to the carboxyl-terminated polyamic acid isoimide cyclization reaction, and the added mass of the first catalyst is 0.5 to 1.5 times the molar number of the dibasic acid anhydride. The first catalyst is selected from one or more of the combined catalysts pyridine / trifluoroacetic anhydride, 4-dimethylaminopyridine / dicyclohexylcarbodiimide, 4-dimethylaminopyridine / N,N'-diisopropylcarbodiimide, 4-dimethylaminopyridine / 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride. The molar ratio between the combined catalysts is 1:1.

[0042] In some embodiments, in the cyclization reaction of the carboxyl-terminated polyamic acid isoimide in step S12, The reaction temperature is 30-45°C and the reaction time is 2-6h.

[0043] In some embodiments, the preparation reaction of the carboxyl-terminated polyisoimide in step S1 is carried out in a first solvent to facilitate the completion of the reaction process in a homogeneous medium system.

[0044] In some embodiments, the first solvent is selected from one or more of 1,3-dimethyl-2-imidazolidinone (DMI), N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0045] In some embodiments, the carboxyl-terminated polyisoimide and the hydroxy-terminated polyphenylene ether in step S21 are subjected to an esterification polycondensation reaction. The molar ratio of the hydroxy-terminated polyphenylene ether to the carboxyl-terminated polyisoimide is 1:(1.0-1.6). More specifically, the molar ratio of the hydroxy-terminated polyphenylene ether to the carboxyl-terminated polyisoimide is 1:(1.0-1.3).

[0046] In some embodiments, in the esterification polycondensation reaction of step S21, the reaction is carried out in a second solvent, and the second solvent is selected from one or more of 1,3-dimethyl-2-imidazolidinone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0047] In some embodiments, in the esterification polycondensation reaction of step S21, the reaction temperature is 140-210° C., and the reaction time is 4-12 hours.

[0048] In some embodiments, a second catalyst is added to the esterification polycondensation reaction of step S21, and the added mass of the second catalyst is 0.005 to 0.05 times that of the carboxyl-terminated polyisoimide, and the second catalyst is selected from one or more of dicyclohexylcarbodiimide, 4-dimethylaminopyridine, N,N'-diisopropylcarbodiimide, N,N'-diisopropylcarbodiimide / 4-dimethylaminopyridine, 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride / N,N'-diisopropylcarbodiimide.

[0049] Since the active end group (-OH) of the terminal hydroxylated polyphenylene ether is connected to the benzene ring, its reaction activity is lower than that of the end group (-OH) of the fatty chain hydrocarbon, and the nucleophilic-elimination polycondensation reaction is relatively difficult. In the preparation method, a catalyst is added to the esterification polycondensation reaction in step S2, which can effectively promote the polycondensation reaction. At the same time, the carbodiimide catalyst can form an active intermediate between the terminal carboxyl group and the catalyst, which effectively improves the group selectivity of the catalytic reaction process and improves the reaction efficiency and conversion rate.

[0050] In some embodiments, after the esterification and polycondensation reaction of step S21 is completed, post-treatment includes the following steps: 1) cooling to room temperature and filtering to remove solid impurities; 2) transferring the filtrate to a single-necked flask and adding a third catalyst; 3) connecting the single-necked flask to a rotary evaporator, and distilling off part of the solvent under reduced pressure to obtain a polyphenylene ether hybridized carboxyl-terminated polyisoimide solution with a solid content of 50-70%.

[0051] In some embodiments, a third catalyst is added in a post-treatment step after the esterification polycondensation reaction of step S21 is completed, and the amount of the third catalyst added is 0.001 to 0.02 times the mass of the polyphenylene ether hybridized carboxyl-terminated polyisoimide. The third catalyst is selected from one or more of 1,8-diazabicyclo [5.4.0] undecene, 2, 4, 6-tris (dimethylaminomethyl) phenol, triethanolamine, and triethylamine.

[0052] In some embodiments, the isomerization reaction of the polyphenylene ether hybrid polyisoimide to obtain the polyphenylene ether hybrid polyimide in step S22 is completed by the following steps: 1) casting the polyphenylene ether hybrid polyisoimide solution into a film on a polytetrafluoroethylene plate; 2) placing it in a forced air drying oven and drying the solvent in the temperature range of 90 to 120°C; 3) carrying out the isomerization reaction of the polyphenylene ether hybrid polyisoimide according to a heating program of 150°C / 1h+170°C / 2h+190°C3h+210°C / 4h+230°C / 2h to obtain the polyphenylene ether hybrid polyimide.

[0053] Another embodiment of the present invention provides a method for preparing the polyphenylene ether hybrid polyimide film as described above, comprising the following steps: The carboxyl-terminated polyphenylene ether hybrid polyimide, polyphenylene ether filler and epoxy branched crosslinking agent are weighed in weight proportion, added into a solvent and mixed evenly to obtain a film material, and the film material is cured to obtain a polyphenylene ether hybrid polyimide film.

[0054] Another embodiment of the present invention provides a flexible circuit board, comprising a laminated ketone-coated film and the polyphenylene ether hybrid polyimide adhesive film as described above.

[0055] The present invention is further described below by way of examples.

[0056] Example 1 This example is used to illustrate the preparation method of the polyphenylene ether hybrid polyimide film disclosed in the present invention, which includes the following steps: S1. Preparation of carboxyl-terminated polyisoimide: S11: Dissolve 0.01 mol (2.0023 g) of 4,4'-diaminodiphenyl ether in 10 ml of 1,3-dimethyl-2-imidazolidinone to obtain a colorless transparent solution, and transfer it to a 100 ml three-necked flask with an electric stirring device; stir and dissolve 0.01 mol (3.1025 g) of 4,4'-biphenyl ether tetracarboxylic dianhydride in 30 ml of 1,3-dimethyl-2-imidazolidinone, and heat to 90 °C until a light yellow transparent solution is obtained; dissolve 0.00053 mol (0.0800 g) of 3,5-diaminobenzoic acid in 10 ml of 1,3-dimethyl-2-imidazolidinone was added to obtain a colorless transparent solution; under ice-water bath and stirring conditions, 4,4'-biphenyl ether tetracarboxylic dianhydride solution (one quarter of the total solution was added each time, with a time interval of 0.5h) was added to the three-necked flask and reacted at a constant temperature for 1h; 3,5-diaminobenzoic acid solution was continuously added to the reaction system, and the constant temperature reaction was continued, and the actual acid value of the reaction system was measured every 1h until the theoretical acid value was reached, and the reaction was stopped to obtain a 3,5-diaminobenzoic acid-terminated polyamic acid solution.

[0057] S12: Add 0.01 mol (1.64 g) of the first catalyst 4-dimethylaminopyridine / dicyclohexylcarbodiimide to the 3,5-diaminobenzoic acid-terminated polyamic acid solution obtained in S11. When the solution becomes transparent, stir the reaction at a constant temperature of 40°C until white insoluble matter appears. Continue the reaction for 6 hours to obtain a white suspension of carboxyl-terminated polyisoimide. Filter to remove the white suspended matter to obtain a light yellow transparent carboxyl-terminated polyisoimide solution.

[0058] S2. Preparation of polyphenylene ether hybrid polyimide: 0.0095 mol of hydroxylated polyphenylene ether (Mn=2550) was stirred and dissolved in 10 ml of 1,3-dimethyl-2-imidazolidinone to obtain a light yellow colorless transparent solution; the solution was mixed with the light yellow transparent carboxyl-terminated polyisoimide solution obtained in S12 and transferred into a 150 ml four-necked flask equipped with an electric stirrer and a N2 device; while stirring, 0.1040 g of the second catalyst 4-dimethylaminopyridine was added, nitrogen was introduced, and the temperature was raised to 180 ℃, constant temperature reaction for 10h; after the reaction is completed, the reaction system is cooled to a temperature range of 100-140℃, and vacuum distilled for 1-1.5h to evaporate the water molecules and part of the solvent produced by the reaction; a light brown transparent viscous solution with a solid content of 50% is obtained, which is the polyphenylene ether hybridized carboxyl-terminated polyisoimide solution; the temperature is further lowered to 60-80℃, and 0.0522g of the third catalyst 1,8-diazabicyclo 5.4.0] undecene is added to the solution, and stirred and mixed for 0.5h. The precursor solution of the polyphenylene ether hybridized carboxyl-terminated polyimide solution is obtained.

[0059] S3, preparation of polyphenylene ether hybrid polyimide: The polyphenylene ether hybrid carboxyl-terminated polyimide solution precursor obtained in S2 is cast on a polytetrafluoroethylene plate, transferred to a forced air drying oven, the solvent is dried at a temperature range of 90 to 120°C, and an isomerization reaction is carried out according to a temperature increase program of 150°C / 1h+170°C / 2h+190°C3h+210°C / 4h+230°C / 2h to obtain a polyphenylene ether hybrid polyimide film. The number average molecular weight of the polyphenylene ether hybrid polyimide is measured to be 179832.

[0060] S3, hydroxyl activation treatment of polyphenylene ether filler: dissolve polyphenylene ether in chlorobenzene, add liquid bromine, heat to 130°C for bromination reaction, react for 2 hours, obtain bromomethylated polyphenylene ether solution, precipitate and dry to obtain bromomethylated polyphenylene ether; soak bromomethylated polyphenylene ether in 4 mol / L sodium hydroxide solution, react at 90°C for 60 hours, obtain hydroxylated polyphenylene ether solution, wash and dry to obtain polyphenylene ether filler; S3. Weigh carboxyl-terminated polyphenylene ether hybrid polyimide, polyphenylene ether filler and 2,2'-[[2-ethyl-2-[(oxiranylmethoxy)methyl]-1,3-dipropyl]bis(oxymethylene)]bis(oxirane) in a weight ratio of 55:25:10, add them into a solvent and mix them evenly to obtain a film material, apply the film material on a substrate, and heat and cure to obtain a polyphenylene ether hybrid polyimide film.

[0061] Example 2 This example is used to illustrate the preparation method of the polyphenylene ether hybrid polyimide adhesive film disclosed in the present invention, and includes most of the operation steps in the following Example 1, except that: The weight ratio of the carboxyl-terminated polyphenylene ether hybrid polyimide, the polyphenylene ether filler and 2,2'-[[2-ethyl-2-[(oxiranylmethoxy)methyl]-1,3-dipropyl]bis(oxymethylene)]bis(oxirane) is 70:20:5.

[0062] Example 3 This example is used to illustrate the preparation method of the polyphenylene ether hybrid polyimide adhesive film disclosed in the present invention, and includes most of the operation steps in the following Example 1, except that: The weight ratio of the carboxyl-terminated polyphenylene ether hybrid polyimide, the polyphenylene ether filler and the 2,2'-[[2-ethyl-2-[(oxiranylmethoxy)methyl]-1,3-dipropyl]bis(oxymethylene)]bis(oxirane) is 40:30:15.

[0063] Comparative Example 1 This comparative example provides a method for preparing a polyphenylene ether hybrid polyimide adhesive film, which includes most of the operating steps in Example 1, except that: The polyphenylene ether filler is not subjected to hydroxyl activation treatment, and a polyphenylene ether filler that is not hydroxyl activated is used.

[0064] Comparative Example 2 This comparative example provides a method for preparing a polyphenylene ether hybrid polyimide adhesive film, which includes most of the operating steps in Example 1, except that: Polyimide is used to replace carboxyl-terminated polyphenylene ether hybrid polyimide.

[0065] Performance Testing The samples prepared in the above examples and comparative examples were subjected to the following performance tests: Heat resistance test: (1) The prepared adhesive film and copper film are combined to form a copper-clad laminate. Samples of the matured product are taken from the left, middle, and right sides. Samples of 5±1cm×5±1cm are cut and placed on the side of the soldering furnace for preheating for 5-10 minutes. (2) Immerse the samples in a constant temperature solder solution at 300 ± 5°C for 10 seconds, then take them out and observe whether there is any delamination or blistering / bulging on the surface.

[0066] 2. Dielectric performance test: (1) Dry the test piece in an oven at 105°C ± 5°C for 1 hour (2) Then put the test piece into the network analyzer for testing at a test frequency of 10 GHz. The dielectric constant and dielectric loss are obtained. 3. Mechanical properties test The mechanical properties test of the film was carried out on a Shenzhen Xinsansi CMT-6503 microcomputer-controlled electronic universal tensile testing machine to test the tensile properties of the film. Test conditions: test temperature: room temperature, sample size: 100mm×10mm×0.25mm, loading speed: 2mm / min. 4. Moisture absorption test: (1). Dry the test piece in an oven at 105°C ± 5°C for 1 hour. (2) Take out the test piece, put it into the desiccator, and cool it for 10 minutes. (3) Weigh the test piece W1 to an accuracy of 0.1 mg. (4) Immersion: Immerse the weighed samples in distilled water or pure water at 23 ± 1.1°C for a total of 24 hours ± 0.5 hours. (5) Weighing: After wiping with absorbent paper, weigh W2 immediately with an accuracy of 0.1 mg. (6). Calculation formula: Water absorption = (W2-W1) / W1 × 100% The test results obtained are entered in Table 1.

[0067] Table 1 It can be seen from the test results in Table 1 that the polyphenylene ether hybrid polyimide film prepared by the preparation method provided by the present invention has excellent properties such as temperature resistance, bonding strength, low dielectric, and low moisture absorption rate, and can solve the problems of low bonding performance and large dielectric parameters existing in traditional polyimide film materials, and is conducive to the preparation of high-performance films that meet high-speed and high-frequency operation and adapt to vehicle driving environments.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A polyphenylene ether hybrid polyimide film, characterized in that: It consists of the following components by weight: 40-70 parts of carboxyl-terminated polyphenylene ether hybrid polyimide, 15-30 parts of polyphenylene ether filler, and 5-15 parts of epoxy branched crosslinking agent; Wherein, the polyphenylene ether filler is treated with hydroxyl activation; The epoxy branched crosslinking agent is a multifunctional epoxy resin having a branched terminal group being an epoxy group.

2. The polyphenylene ether hybrid polyimide adhesive film according to claim 1, characterized in that: The polyphenylene ether hybrid polyimide adhesive film comprises the following components by weight: 60-70 parts of carboxyl-terminated polyphenylene ether hybrid polyimide, 20-30 parts of polyphenylene ether filler, and 5-10 parts of epoxy branched crosslinking agent.

3. The polyphenylene ether hybrid polyimide adhesive film according to claim 1, characterized in that: The hydroxyl activation treatment method of the polyphenylene ether filler is: The polyphenylene ether is dissolved in a solvent, and liquid bromine is added to carry out a bromination reaction to obtain a bromomethylated polyphenylene ether solution, and the bromomethylated polyphenylene ether is obtained after precipitation and drying; the bromomethylated polyphenylene ether is immersed in a sodium hydroxide solution, and reacted at a constant temperature of 80°C to 95°C to obtain a hydroxylated polyphenylene ether solution, and the polyphenylene ether filler is obtained after washing and drying.

4. The polyphenylene ether hybrid polyimide adhesive film according to claim 1, characterized in that: The epoxy branched crosslinking agent is selected from 2,2'-[[2-ethyl-2-[(oxiranylmethoxy)methyl]-1,3-dipropyl]bis(oxymethylene)]bisoxirane.

5. The polyphenylene ether hybrid polyimide adhesive film according to claim 1, characterized in that: The structure of the carboxyl-terminated polyphenylene ether hybrid polyimide is shown in Structural Formula 1: Structural formula 1 Wherein, m is selected from an integer of 5 to 30, R' is selected from a polyphenylene ether segment, and R is selected from a polyimide segment.

6. The polyphenylene ether hybrid polyimide adhesive film according to claim 5, characterized in that: The R is selected from the segment shown in structural formula 2: Structural formula 2 Wherein, n is selected from an integer ranging from 5 to 90.

7. The polyphenylene ether hybrid polyimide adhesive film according to claim 5, characterized in that: The R' is selected from the segment shown in structural formula 3: Structural formula 3 Wherein, I is selected from an integer of 3 to 10.

8. The polyphenylene ether hybrid polyimide adhesive film according to claim 5, characterized in that: The R' is selected from the segment shown in structural formula 4: Structural formula 4 Wherein, d is selected from an integer ranging from 8 to 25.

9. The polyphenylene ether hybrid polyimide adhesive film according to claim 1, characterized in that: The molecular weight of the polyphenylene ether hybrid polyimide is 10,000-400,000.

10. A copper clad laminate, characterized in that: The invention comprises a copper foil and a polyimide film layer, wherein the polyimide film layer is arranged on the copper foil, and the polyimide film layer is prepared by the preparation method according to any one of claims 1 to 9.

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