A multifunctional imide resin and its preparation method

Abstract

This invention relates to the field of electronic packaging resin technology, and discloses a multifunctional imide resin and its preparation method. The multifunctional imide resin of this invention overcomes the bottlenecks of ultra-low dielectric hydrocarbon resin systems, such as insufficient peel strength, thermal expansion mismatch, and limited heat resistance, through a molecular structure combining a non-polarized main chain, active end-capping, multifunctionality, rigid ring structure, and flexible side chains. It can be directly applied as a core modifying component in the fields of prepreg (PP), bonded sheets, and packaging substrates for high-frequency and high-speed copper-clad laminates, possessing significant technological advantages and broad prospects for industrial application.

Description

Technical Field

[0001] This invention relates to the field of electronic packaging resin technology, and in particular to a multifunctional imide resin and its preparation method. Background Technology

[0002] With the rapid development of 5G / 6G communication base stations, AI high-performance servers, and high-speed digital circuits, high-frequency and high-speed copper-clad laminates (CCLs) are placing increasingly stringent comprehensive performance requirements on the matrix resin: it must possess ultra-low dielectric constant Dk < 3.0 and extremely low dielectric loss Df < 0.003, high glass transition temperature Tg ≥ 255℃, excellent heat resistance Td5% ≥ 380℃, low coefficient of thermal expansion CTEz ≤ 2.0%, and crucially, high interlayer peel strength ≥ 0.7 N / mm. Hydrocarbon resins, such as hydrogenated polybutadiene and cyclic olefin copolymers, exhibit the best dielectric properties among currently available commercial resins due to their highly non-polar molecular structure and lack of heteroatomic polar groups, and have become the mainstream main-chain resin component in high-frequency and high-speed CCLs. However, its aliphatic / alicyclic backbone structure also leads to insufficient intrinsic heat resistance: the typical Tg of hydrocarbon resins is generally only 150~220℃, far below the 240℃ threshold required for high-end packaging substrates; at the same time, its CTE (coefficient of thermal expansion along the Z-axis) is >3%, which easily leads to the accumulation of thermal stress at the copper-resin interface during the peak temperature of lead-free reflow soldering at 260℃, exacerbating the risk of delamination and microcracks. In addition, the non-polar surface means that the adhesion to the copper foil relies solely on weak van der Waals forces, and the tensile force on the copper foil is usually no more than 0.5N / mm, making it extremely prone to failure under high temperature and humidity or repeated thermal cycling. This severely restricts its application in high-end packaging substrates and high-reliability PCBs.

[0003] To synergistically improve dielectric properties, mechanical reliability, and heat resistance, the industry commonly employs a ternary composite system of hydrocarbon resin / olefin-terminated polyphenylene ether (PPE) / maleimide. In this system, PPE provides skeletal support, hydrocarbon resin ensures the dielectric performance baseline, and the maleimide component undertakes the crosslinking network construction and interface compatibilization functions. However, traditional bismaleimide (BMI) and polyamine-type maleimide resins suffer from problems such as excessively high reactivity, narrow processing window, high brittleness, insufficient dielectric insulation, and poor compatibility with hydrocarbons leading to easy precipitation. These issues make it difficult to achieve uniform molecular-scale dispersion and controllable gradient crosslinking, thus limiting the performance upper limit of the ternary system.

[0004] When applied to high-frequency, high-speed hydrocarbon resin systems, traditional bismaleimide has a regular structure, is prone to crystallization and precipitation, has a high melting point, and poor solvent solubility. Polyamine-type maleimide resins have significantly improved solubility, brittleness, and melting point in polar solvents compared to traditional bismaleimide, but they still suffer from poor solubility in low-polarity solvents, poor compatibility with low-polarity resin solvents such as hydrocarbon resin systems, and easy precipitation. In general, they all suffer from excessively high reactivity, narrow processing window, high brittleness, and insufficient dielectric insulation. Summary of the Invention

[0005] To address the aforementioned shortcomings, the present invention aims to propose a multifunctional imide resin and its preparation method, thereby solving the performance deficiencies of the traditional "hydrogen resin / olefin-terminated polyphenylene ether / maleimide" ternary composite system.

[0006] To achieve this objective, the present invention adopts the following technical solution: A multifunctional imide resin has the following general structural formula: ; Where n is an integer between 1 and 60; R1 is C2-C 20 Alkyl, C3-C 20 cycloalkyl, C6-C 30 Aryl, nitrogen- and / or oxygen-substituted C2-C 20 Alkyl groups and C3-C atoms containing nitrogen and / or oxygen elements 20 One or more heterocyclic groups; R2 is C2-C 20 Alkyl, C3-C 20 cycloalkyl, C6-C 30 Aryl, nitrogen- and / or oxygen-substituted C2-C 20 Alkyl groups and C3-C atoms containing nitrogen and / or oxygen elements 20 One or more heterocyclic groups; R3 is C2-C 20 Contains unsaturated carbon-bonded hydrocarbon groups, C3-C 20 Contains unsaturated carbon-bonded cyclic hydrocarbon groups, C6-C 30 C2-C containing unsaturated carbon-bonded aryl groups, and containing nitrogen and / or oxygen elements. 20 Heterocyclic groups containing unsaturated carbon bonds and C3-C groups substituted with nitrogen and / or oxygen elements. 20 A group consisting of one or more unsaturated carbon-bonded hydrocarbon groups.

[0007] Preferably, the raw materials for the multifunctional imide resin include cycloolefin succinic anhydride, an olefin compound, a first solvent, a second solvent, an initiator, a capping accelerator, an acidic catalyst, and an active hydrocarbon primary amine containing reactive carbon bonds, wherein, according to the molar ratio, the ratio of cycloolefin succinic anhydride to olefin compound is 0.9~1.1:0.1~3, and the ratio of olefin succinic anhydride to active hydrocarbon primary amine is 0.9~1.1:1~2; The preparation method includes the following steps: A mixture was prepared by dissolving cycloolefin succinic anhydride and olefin compounds in a first solvent; The mixture is added dropwise to a second solvent at a temperature of 50-100℃ for 1-5 hours, and the reaction is continued for 1-5 hours. After the addition is completed, an initiator and a capping accelerator are added and the reaction is continued for 1-5 hours to obtain a cycloolefin succinic anhydride-olefin compound copolymer solution. A solution of cycloolefin succinic anhydride-olefin compound copolymer was reacted with an active hydrocarbon primary amine at 20-40°C for 2-5 hours to obtain maleimide acid. Add an acidic catalyst to maleimide acid, reflux at 60~130℃ for 2h~6h to dehydrate and close the ring, wash with water, heat to 60~160℃ and vacuum for 1~5h to remove solvent, and obtain a multifunctional imide resin.

[0008] Preferably, the olefinic compound is C2-C. 100 Alkene-based compounds that are monofunctional or polyfunctional, containing nitrogen, phosphorus, and oxygen elements or not containing nitrogen, phosphorus, and oxygen elements; The olefinic cyclic dicarboxylic anhydride is C2-C. 50 olefinic cyclic dicarboxylic anhydrides; The active hydrocarbon-based primary amine is C2-C. 50 The active hydrocarbon primary amine, wherein the active hydrocarbon group includes alkenes, alkynes, cyclopropanes or benzocyclobutene.

[0009] Preferably, the initiator is an azo radical initiator or a peroxide radical initiator, and the amount used is 3% to 8% of the total mass of the cycloalkenyl succinic anhydride and the olefin compound.

[0010] Preferably, the second solvent is a hydrocarbon containing a benzene ring with 7-10 carbon atoms, and the amount used is 300% to 500% of the total mass of the cycloalkenyl succinic anhydride and the olefin compound.

[0011] Preferably, the end-capping accelerator is a phenylalkane, which is selected from one or a combination of several of 2,3-dimethyl-2,3-diphenylbutane, diphenylmethane, 3,4-dimethyl-3,4-diphenylhexane, 1,3-diphenylbutane, 1,4-diphenylbutane, diphenylethane, and diphenylpropane, and is used in an amount of 0.5% to 2% of the total mass of the cycloalkenyl succinic anhydride and the olefin compound.

[0012] Preferably, the first solvent is a mixture of a hydrocarbon solvent containing a benzene ring with 7-10 carbon atoms and a ketone solvent with 3-8 carbon atoms, wherein the mass ratio of ketone solvent to hydrocarbon solvent is 5:1, and the amount of the first solvent is 30% to 100% of the total mass of the cycloalkenyl succinic anhydride and the olefin compound.

[0013] Preferably, the acidic catalyst is p-toluenesulfonic acid, and the amount used is 5% to 15% of the total mass of cycloolefin succinic anhydride, olefin compound and active hydrocarbon primary amine.

[0014] The technical solution provided by this invention may include the following beneficial effects: 1. When applied to high-frequency, high-speed hydrocarbon resin systems, the multifunctional imide resin of the present invention exhibits significant structural and performance advantages compared to traditional bismaleimide (BMI) and polyamine-type maleimide resins, specifically in the following aspects: Nonpolar backbone and active end-capping design: Nonpolar segments are introduced into the backbone via free radical polymerization, and then imidized and cyclic-closed using active hydrocarbon-based primary amines to form a structure with multifunctional active olefin end-capping. This structure not only effectively reduces molecular polarity, achieving a significant decrease in dielectric constant (Dk≈3.0@10GHz), but its nonpolar characteristics also ensure high compatibility with hydrocarbon resins, significantly improving solubility in nonpolar solvents such as toluene and xylene, achieving complete miscibility and avoiding phase separation.

[0015] Multifunctional structure promotes deep co-crosslinking: The main molecular chain contains multiple reactive hydrocarbon side chains with unsaturated carbon bonds, endowing the resin with high functionality. During thermosetting, these unsaturated carbon bond segments can undergo efficient free radical co-crosslinking reactions with components such as hydrocarbon resins and polyphenylene ether (PPE), constructing a covalent transition layer rich in polar imide bonds (-CO-N-CO-) and carbon-carbon double bonds (C=C) in situ at the copper foil / resin interface, significantly enhancing interfacial adhesion strength and achieving a peel strength of ≥0.7 N / mm for the copper foil.

[0016] Rigid imide rings enhance thermal stability: The main chain consists of repeating rigid five-membered imide heterocycles, which have a strong π-π stacking effect and steric hindrance, effectively suppressing chain segment movement, thereby significantly improving the glass transition temperature (Tg≥255℃) and thermal decomposition temperature (Td5%≥380℃) of the material, meeting the long-term thermal stability requirements of high-frequency and high-speed applications.

[0017] A molecular design that combines rigidity and flexibility: The molecular structure combines the synergistic effect of a rigid imide ring and flexible active hydrocarbon side chains. The rigid skeleton ensures high-temperature stability, while the flexible segments effectively alleviate internal stress and suppress precipitation tendency, while maintaining excellent processing fluidity. This rigid-flexible balance design achieves a synergistic effect of multiple properties, including high Tg, high heat resistance, low dielectric constant, high-strength adhesion, and excellent anti-precipitation properties.

[0018] In summary, the resin of this invention overcomes the bottlenecks of ultra-low dielectric hydrocarbon resin systems, such as insufficient peel strength, thermal expansion mismatch, and limited heat resistance, through its molecular structure combining main chain nonpolarization, active end-capping, multifunctionality, rigid ring structure, and flexible side chains. It can be directly applied as a core modifying component in the fields of prepreg (PP), bonded sheets, and packaging substrates for high-frequency, high-speed copper-clad laminates, demonstrating significant technological advancement and broad prospects for industrial application.

[0019] 2. The preparation method of this invention is based on an olefin-based compound-cyclic olefin-succinic anhydride copolymer and an unsaturated alkane-based primary amine, which undergoes an amidation-cyclization dehydration two-step reaction to prepare a hyperbranched multifunctional imide resin. By copolymerizing the olefin-based compound with the cyclic olefin-succinic anhydride to form an alkane skeleton and introducing multiple imide-emitting anhydride sites, and using active alkyl-based primary amines for steric hindrance regulation, a novel multifunctional resin with a three-dimensional hyperbranched topology and multiple olefin / imine groups at the ends is constructed. Attached Figure Description

[0020] Figure 1 This is the general structural formula of the multifunctional imide resin of the present invention.

[0021] Figure 2 This is a GPC diagram of Embodiment 1 of the present invention.

[0022] Figure 3 This is the simplified reaction formula for Example 3 of the present invention.

[0023] Figure 4 This is a schematic diagram of the molecular structure when n=3 in the general formula of Example 3 of the present invention.

[0024] Figure 5 This is a schematic diagram of the molecular structure when n=1 and m=1 in the general formula of Example 3 of the present invention. Detailed Implementation

[0025] To facilitate understanding of the present invention, a more complete description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0026] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] A multifunctional imide resin, such as Figure 1 As shown, the general formula for the structure is as follows: ; Where n is an integer between 1 and 60; R1 is C2-C 20 Alkyl, C3-C 20 cycloalkyl, C6-C 30 Aryl, nitrogen- and / or oxygen-substituted C2-C 20 Alkyl groups and C3-C atoms containing nitrogen and / or oxygen elements 20 One or more heterocyclic groups; R2 is C2-C 20 Alkyl, C3-C 20 cycloalkyl, C6-C 30 Aryl, nitrogen- and / or oxygen-substituted C2-C 20 Alkyl groups and C3-C atoms containing nitrogen and / or oxygen elements 20 One or more heterocyclic groups; R3 is C2-C 20 Contains unsaturated carbon-bonded hydrocarbon groups, C3-C 20 Contains unsaturated carbon-bonded cyclic hydrocarbon groups, C6-C 30 C2-C containing unsaturated carbon-bonded aryl groups, and containing nitrogen and / or oxygen elements. 20 Heterocyclic groups containing unsaturated carbon bonds and C3-C groups substituted with nitrogen and / or oxygen elements. 20 A group consisting of one or more unsaturated carbon-bonded hydrocarbon groups.

[0029] When applied to high-frequency, high-speed hydrocarbon resin systems, the multifunctional imide resin of this invention exhibits significant structural and performance advantages compared to traditional bismaleimide (BMI) and polyamine-type maleimide resins, specifically in the following aspects: (1) Nonpolar backbone and active end cap design: Nonpolar segments are introduced into the backbone through free radical polymerization, and imidization ring closure is performed using active hydrocarbon primary amines to form a structure with multifunctional active olefin end caps. This structure not only effectively reduces molecular polarity and achieves a significant decrease in dielectric constant (Dk≈3.0@10GHz), but its nonpolar characteristics are also highly compatible with hydrocarbon resins, significantly improving solubility in nonpolar solvents such as toluene and xylene, achieving complete miscibility and avoiding phase separation.

[0030] (2) Multifunctional structure promotes deep co-crosslinking: The main molecular chain contains multiple reactive hydrocarbon side chains with unsaturated carbon bonds, which endows the resin with high functionality. During thermosetting, these unsaturated carbon bond segments can undergo efficient free radical co-crosslinking reactions with components such as hydrocarbon resin and polyphenylene ether (PPE), and construct a covalent transition layer rich in polar imide bonds (-CO-N-CO-) and carbon-carbon double bonds (C=C) in situ at the copper foil / resin interface, which greatly enhances the interfacial adhesion strength and achieves a peel strength of ≥0.7N / mm for the copper foil.

[0031] (3) Rigid imide rings enhance thermal stability: The main chain is composed of repeated rigid five-membered imide heterocycles, which have strong π~π stacking effect and steric hindrance, effectively suppressing chain segment movement, thereby significantly improving the glass transition temperature (Tg≥255℃) and thermal decomposition temperature (Td5%≥380℃) of the material, meeting the long-term thermal stability requirements of high-frequency and high-speed application scenarios.

[0032] (4) Molecular design combining rigidity and flexibility: The molecular structure combines the synergistic effect of rigid imide rings and flexible active hydrocarbon side chains. The rigid skeleton ensures high-temperature stability, while the flexible segments effectively relieve internal stress and suppress precipitation tendency, while maintaining excellent processing fluidity. This rigid-flexible balance design achieves multiple synergistic properties such as high Tg, high heat resistance, low dielectric constant, high-strength adhesion and excellent anti-precipitation properties.

[0033] In summary, the resin of this invention overcomes the bottlenecks of ultra-low dielectric hydrocarbon resin systems, such as insufficient peel strength, thermal expansion mismatch, and limited heat resistance, through its molecular structure combining main chain nonpolarization, active end-capping, multifunctionality, rigid ring structure, and flexible side chains. It can be directly applied as a core modifying component in the fields of prepreg (PP), bonded sheets, and packaging substrates for high-frequency, high-speed copper-clad laminates, demonstrating significant technological advancement and broad prospects for industrial application.

[0034] Preferably, the raw materials for the multifunctional imide resin include cycloolefin succinic anhydride, an olefin compound, a first solvent, a second solvent, an initiator, a capping accelerator, an acidic catalyst, and an active hydrocarbon primary amine containing reactive carbon bonds, wherein, according to the molar ratio, the ratio of cycloolefin succinic anhydride to olefin compound is 0.9~1.1:0.1~3, and the ratio of olefin succinic anhydride to active hydrocarbon primary amine is 0.9~1.1:1~2; The preparation method includes the following steps: A mixture was prepared by dissolving cycloolefin succinic anhydride and olefin compounds in a first solvent; The mixture is added dropwise to a second solvent at a temperature of 50-100℃ for 1-5 hours, and the reaction is continued for 1-5 hours. After the addition is completed, an initiator and a capping accelerator are added and the reaction is continued for 1-5 hours to obtain a cycloolefin succinic anhydride-olefin compound copolymer solution. A solution of cycloolefin succinic anhydride-olefin compound copolymer was reacted with an active hydrocarbon primary amine at 20-40°C for 2-5 hours to obtain maleimide acid. Add an acidic catalyst to maleimide acid, reflux at 60~130℃ for 2h~6h to dehydrate and close the ring, wash with water, heat to 60~160℃ and vacuum for 1~5h to remove solvent, and obtain a multifunctional imide resin.

[0035] The preparation method of this invention is based on an olefin-based compound-cycloolefin succinic anhydride copolymer and an unsaturated alkane-based primary amine, which undergoes an amidation-cyclization dehydration two-step reaction to prepare a hyperbranched multifunctional imide resin. By copolymerizing the olefin-based compound with the cycloolefin succinic anhydride to form an alkane skeleton and introducing multiple imide-emitting anhydride sites, and using active alkane-based primary amines for steric hindrance regulation, a novel multifunctional resin with a three-dimensional hyperbranched topology and multiple olefin / imine groups at the ends is constructed.

[0036] It is worth noting that the upper limit of the amount of olefin-based compounds needs to be controlled to avoid the problem that excessive use of olefin-based compounds will lead to an excessive amount of olefin-based flexible chains, thereby disrupting the rigid balance of the structure.

[0037] Preferably, the olefinic compound is C2-C. 100 Alkene-based compounds that are monofunctional or polyfunctional, containing nitrogen, phosphorus, and oxygen elements or not containing nitrogen, phosphorus, and oxygen elements; This may include, but is not limited to: norbornene and its derivatives, cyclododecanetriene, 1,5-cyclooctadiene, 1,5-cyclooctadiene, cyclooctene, cyclohexene, 1,4-cyclohexadiene and 1,4-paradiene, di(vinylbenzyl) ether, di(vinylphenyl) ethane, triallyl isocyanurate, triallyl cyanurate, 1,2,4-trivinylcyclohexane, ethylene, propylene, styrene, divinylbenzene, diallylbenzene, butadiene, isoprene, isoprene, methylstyrene, terpenes, and other olefin-based monofunctional and polyfunctional compounds or copolymers or combinations thereof.

[0038] The olefinic cyclic dicarboxylic anhydride is C2-C. 50 olefinic cyclic dicarboxylic anhydrides; The olefinic cyclic dicarboxylic anhydride may include, but is not limited to, one or more of the following: 5-norbornene-2,3-dicarboxylic anhydride, bicyclo(2.2.2)oct-5-ene-2,3-dicarboxylic anhydride, 1-cyclopentene-1,2-dicarboxylic anhydride, methyl nadic anhydride, nadic anhydride, itaconic anhydride, citraconic anhydride, maleic anhydride, etc. The active hydrocarbon-based primary amine is C2-C. 50 The active hydrocarbon primary amine, wherein the active hydrocarbon group includes alkenes, alkynes, cyclopropanes or benzocyclobutene.

[0039] The active hydrocarbon primary amines may include, but are not limited to, one or more of the following: 4-penten-1-amine, 5-hexen-1-amine, 2-methylallylamine, ethyleneamine, vinylaniline, ethynylaniline, allylamine, propyneamine, etc.

[0040] Preferably, the initiator is an azo radical initiator or a peroxide radical initiator, and the amount used is 3% to 8% of the total mass of the cycloalkenyl succinic anhydride and the olefin compound.

[0041] Initiators can be organic peroxides, such as benzoyl peroxide, diisopropylbenzene peroxide, cumene hydroperoxide, ditert-butyl peroxide, dodecyl peroxide, tert-butyl peroxide, diisopropyl peroxide, etc., or azo compounds, such as azobisisobutyronitrile, azobisisoheptanenitrile, etc.

[0042] In a preferred embodiment, the initiator is an organic peroxide, selected from one or more combinations of hydroperoxides, dialkyl peroxides, and ester peroxides. In a preferred embodiment, the selected peroxide initiator is a high-temperature initiator, with an activation energy of 138-183 KJ / mol at temperatures above 100°C. In a preferred embodiment, the high-temperature initiator is selected from one or more combinations of cumene hydroperoxide, tert-butyl hydroperoxide, and di-tert-butyl peroxide.

[0043] Preferably, the second solvent is a hydrocarbon containing a benzene ring with 7-10 carbon atoms, and the amount used is 300% to 500% of the total mass of the cycloalkenyl succinic anhydride and the olefin compound.

[0044] Specific solvents include toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, propylbenzene, cumene, diethylbenzene, butene-butanediol, isobutylbenzene, or p-methylcumene. Toluene, cumene, or mesitylene are preferred, but the above solvents are not limited. These solvents have good compatibility with olefinic compounds, low polarity, and are conducive to the formation of alternating structures.

[0045] Preferably, the end-capping accelerator is a phenylalkane, which is selected from one or a combination of several of 2,3-dimethyl-2,3-diphenylbutane, diphenylmethane, 3,4-dimethyl-3,4-diphenylhexane, 1,3-diphenylbutane, 1,4-diphenylbutane, diphenylethane, and diphenylpropane, and is used in an amount of 0.5% to 2% of the total mass of the cycloalkenyl succinic anhydride and the olefin compound.

[0046] In a preferred embodiment, the end-capping accelerator is 2,3-dimethyl-2,3-diphenylbutane.

[0047] Using 2,3-dimethyl-2,3-diphenylbutane as a capping accelerator, in conjunction with di-tert-butyl peroxide initiator, a styrene-maleic anhydride copolymer was prepared with low molecular weight, low yellowness, and stable acid value.

[0048] Preferably, the first solvent is a mixture of a hydrocarbon solvent containing a benzene ring with 7-10 carbon atoms and a ketone solvent with 3-8 carbon atoms, wherein the mass ratio of ketone solvent to hydrocarbon solvent is 5:1, and the amount of the first solvent is 30% to 100% of the total mass of the cycloalkenyl succinic anhydride and the olefin compound.

[0049] The ketone solvent in the first solvent may be selected from acetone, butanone, methyl acetone, 2-pentanone, 3-pentanone, 3-methyl-2-butanone, 2-hexanone, 3-hexanone, 2-methyl-3-pentanone, 3,3-dimethyl-2-butanone, 4-methyl-2-pentanone, 2-heptanone, 3-heptanone, 4-heptanone, 2,4-dimethyl-3-pentanone, 2-octanone, 2,6-dimethyl-4-heptanone, cyclopentanone, cyclohexanone, or cycloheptanone, etc. Preferably, the hydrocarbon solvent in the first solvent is the same as that in the second solvent, and the ketone solvent is preferably butanone or cyclohexanone, but is not limited to the above solvents.

[0050] Because the secondary solvent of aromatic hydrocarbons has low polarity, it has very low solubility for maleic anhydride. The added ketone solvent mainly serves as a solubilizer.

[0051] Preferably, the acidic catalyst is p-toluenesulfonic acid, and the amount used is 5% to 15% of the total mass of cycloolefin succinic anhydride, olefin compound and active hydrocarbon primary amine.

[0052] p-Toluenesulfonic acid, a strongly acidic protonable reaction intermediate (such as the acyloxy anion generated by the condensation of maleic anhydride and diamine), lowers the reaction activation energy, accelerates nucleophilic attack and water molecule elimination, thereby efficiently promoting the condensation reaction and the ring-closing formation of the imide ring, and reducing the dielectric property degradation caused by residual carboxyl groups. It can maintain structural stability and catalytic activity in high temperature or complex reaction media, avoiding activity loss due to volatilization or decomposition. At the same time, its excellent solubility and mild properties can effectively inhibit gelation and monomer self-polymerization, ensuring stable molecular weight distribution. In addition, the catalyst is easy to remove and can be separated and recovered from the reaction system by water washing extraction, avoiding the impact of residues on electrical insulation and resistance to damp heat.

[0053] Example 1 Weigh out 50 parts of maleic anhydride and 50 parts of styrene according to the weight parts, and use 10 parts of toluene and 50 parts of butanone as the second solvent. Mix the above materials evenly to obtain a mixture. 400 parts of toluene were added as a second solvent to a reactor equipped with a reflux condenser and a water-separating agitator. The reactor was then placed in an oil bath at 90°C. The initiator is 5 parts of di-tert-butyl peroxide, and the end-capping accelerator is 1 part of 2,3-dimethyl-2,3-diphenylbutane. The initiator and end-capping accelerator are dissolved in 10 parts of toluene and mixed evenly to obtain a mixed solution of initiator and end-capping accelerator. The mixture was added dropwise into the reactor over 1 hour, followed by another hour of reaction. Then, 5 parts of di-tert-butyl peroxide were used as an initiator and 1 part of 2,3-dimethyl-2,3-diphenylbutane as an end-capping accelerator. The initiator and end-capping accelerator were dissolved in 10 parts of toluene and added dropwise into the reactor over 1 hour, followed by another hour of reaction. The mixture was then cooled to room temperature to obtain a cycloolefin succinic anhydride-olefin compound copolymer solution. According to the molar ratio of maleic anhydride: allylamine = 1:1, allylamine was added to a cycloolefin succinic anhydride-olefin compound copolymer solution and reacted for 3 h at 20~40℃ to obtain maleimide acid. Add 5 parts of p-toluenesulfonic acid to maleimide acid and react at 75-80℃ for two hours. Then, raise the temperature to reflux and maintain reflux for 6 hours, while continuously separating the reaction byproduct water using a condenser. After the reaction, cool to 60-80℃ and wash five times with water. The washing steps are as follows: add 130 parts of deionized water, maintain the temperature at 60-80℃ and stir for 30 minutes, let stand and separate the lower aqueous phase mixture. In the second water wash, use a 3% sodium hydroxide aqueous solution instead of deionized water. Finally, raise the temperature to 100-130℃ and remove the toluene solvent under reduced pressure to obtain the polyfunctional imide resin. The acid value of the polyfunctional imide resin is 0.35 mg KOH / g. Figure 2 As shown, the weight-average molecular weight is 5165 g / mol, and the general structural formula is as follows: , Where 1≤n≤50.

[0054] The acid value was determined by titration with KOH solution. 1.5g of polymer solution was accurately weighed and dissolved in a mixed solvent of 90g acetone and 10g water. The solution was then titrated with KOH aqueous solution using a neutralization titration method. The acid value (mgKOH / g) per 1g of polymer was determined from the polymer concentration.

[0055] The weight-average molecular weight was determined by GPC. 0.01 g of the sample was weighed and dissolved in 10 mL of tetrahydrofuran. The sample was tested using a Waters gel permeation chromatography (GPC) system. An Agilent MIXED-D column and a Shodex KF802 column were used in series. The mobile phase was tetrahydrofuran and the flow rate was 1 mL / min.

[0056] Example 2 Weigh out 38 parts of maleic anhydride and 62 parts of nadic anhydride according to the weight parts, and use 10 parts of toluene and 50 parts of butanone as the second solvent. Mix the above materials evenly to obtain a mixture. 400 parts of toluene were added as a second solvent to a reactor equipped with a reflux condenser and a water-separating agitator. The reactor was then placed in an oil bath at 90°C. The initiator is 5 parts of di-tert-butyl peroxide, and the end-capping accelerator is 1 part of 2,3-dimethyl-2,3-diphenylbutane. The initiator and end-capping accelerator are dissolved in 10 parts of toluene and mixed evenly to obtain a mixed solution of initiator and end-capping accelerator. The mixture was added dropwise into the reactor over 1 hour, followed by another hour of reaction. Then, 5 parts of di-tert-butyl peroxide were used as an initiator and 1 part of 2,3-dimethyl-2,3-diphenylbutane as an end-capping accelerator. The initiator and end-capping accelerator were dissolved in 10 parts of toluene and added dropwise into the reactor over 1 hour, followed by another hour of reaction. The mixture was then cooled to room temperature to obtain a cycloolefin succinic anhydride-olefin compound copolymer solution. According to the molar ratio (maleic anhydride + nadic anhydride): allylamine = 1:1.1, allylamine was added to the cycloolefin succinic anhydride-olefin compound copolymer solution and reacted for 3 h at 20~40℃ to obtain maleimide acid; Add 15 parts of p-toluenesulfonic acid to maleimide acid and react at 75-80℃ for two hours. Then, heat to reflux and maintain reflux for 6 hours, while continuously separating the reaction byproduct water using a condenser. After the reaction, cool to 60-80℃ and wash five times with water. The washing steps are as follows: add 150 parts of deionized water, maintain temperature at 60-80℃ and stir for 30 minutes, allow to stand and separate the lower aqueous phase mixture. In the second wash, use a 3% sodium hydroxide aqueous solution instead of deionized water. Finally, heat to 100-130℃ and remove toluene solvent under reduced pressure to obtain a multifunctional imide resin. The multifunctional imide resin has an acid value of 0.23 mg KOH / g, a weight-average molecular weight of 4968 g / mol, and the general structural formula is as follows: , Where 1≤n≤50.

[0057] Example 3 According to the weight parts, weigh 66 parts of maleic anhydride and 33 parts of divinylbenzene, use 10 parts of toluene and 50 parts of butanone as the second solvent, and mix the above materials evenly to obtain a mixture. 400 parts of toluene were added as a second solvent to a reactor equipped with a reflux condenser and a water-separating agitator. The reactor was then placed in an oil bath at 90°C. The initiator is 5 parts of di-tert-butyl peroxide, and the end-capping accelerator is 1 part of 2,3-dimethyl-2,3-diphenylbutane. The initiator and end-capping accelerator are dissolved in 10 parts of toluene and mixed evenly to obtain a mixed solution of initiator and end-capping accelerator. The mixture was added dropwise into the reactor over 1 hour, followed by another hour of reaction. Then, 5 parts of di-tert-butyl peroxide were used as an initiator and 1 part of 2,3-dimethyl-2,3-diphenylbutane as an end-capping accelerator. The initiator and end-capping accelerator were dissolved in 10 parts of toluene and added dropwise into the reactor over 1 hour, followed by another hour of reaction. The mixture was then cooled to room temperature to obtain a cycloolefin succinic anhydride-olefin compound copolymer solution. According to the molar ratio of maleic anhydride: vinyl aniline = 1:1.1, vinyl aniline was added to a cycloolefin succinic anhydride-olefin compound copolymer solution and reacted for 3 h at 20~40℃ to obtain maleimide acid; Add 19 parts of p-toluenesulfonic acid to maleimide acid and react at 75-80℃ for two hours. Then, heat to reflux and maintain reflux for 6 hours, while continuously separating the reaction byproduct water using a condenser. After the reaction, cool to 60-80℃ and wash five times with water. The washing steps are as follows: add 190 parts of deionized water, maintain temperature at 60-80℃ and stir for 30 minutes, allow to stand and separate the lower aqueous phase mixture. In the second wash, use a 3% sodium hydroxide aqueous solution instead of deionized water. Finally, heat to 100-130℃ and remove toluene solvent under reduced pressure to obtain a multifunctional imide resin. The multifunctional imide resin has an acid value of 0.41 mg KOH / g, a weight-average molecular weight of 7522 g / mol, and the general structural formula is as follows: , n≥0, m≥0, 1≤n+m≤100; Specific reaction formulas and structural formulas of some products are as follows: Figures 3 to 5 As shown.

[0058] Copper-clad laminates of Examples 4-6 were prepared using the resins of Examples 1-3, copper-clad laminates of Comparative Example 1 were prepared using BMI-2300, and copper-clad laminates of Comparative Example 2 were prepared without the use of polyfunctional imide resin and polyamine maleimide. The resin types used are as follows: TPO9660: Vinyl polyfunctional polyphenylene ether resin, produced by Tongyu New Materials; THC9810: Styrene-modified polycyclic aromatic hydrocarbon resin, produced by Tongyu New Materials; A1536H: Styrene-ethylene / butene block copolymer, manufactured by Kraton Semiconductor, USA; RICON100: Butadiene-styrene copolymer, manufactured by Cray Valley; BMI-2300 (phenylmethane maleimide): a polyamine-type maleimide, manufactured by Yamato Chemical Industries, Ltd., Japan.

[0059] The preparation methods of the copper-clad laminates in Examples 4-6 and Comparative Examples 1-2 are as follows: Step 1: Mix all components except inorganic fillers according to the proportions shown in Table 1 below and stir for 30 minutes to obtain an adhesive solution; Step 2: Add inorganic filler to the adhesive solution and mix thoroughly. Impregnate the glass fiber cloth in the prepreg and bake at 150℃ for 8 minutes to obtain a prepreg. Stack the prepreg in 6 layers and attach copper foil to both sides. Place it in a vacuum hot press and raise the temperature from room temperature to 180℃ at a rate of 3℃ / min. Increase the pressure from 0.2MPa to 4MPa at a rate of 0.1MPa / min. Evacuate to below 80 Torr and maintain the pressure for 2 hours. Then raise the temperature to 250℃ and maintain constant pressure for 5 hours. Depressurize and allow to cool naturally to obtain the copper-clad laminate.

[0060] The performance test was conducted using the following method, and the performance test data is shown in Table 2 below: Resin component solvent compatibility: After the adhesive solution prepared in step 1 was left to stand at room temperature for 24 hours, the precipitation and stratification of the adhesive solution were observed.

[0061] Coefficient of thermal expansion (CTE): Tested according to standard 2.4.41 in IPC-TM-650.

[0062] Glass transition temperature (Tg): Determined according to the DMA test method specified in IPC-TM-650, section 2.4.24.4.

[0063] Dielectric constant (Dk): The dielectric constant at 10 GHz was determined using the plate method according to section 2.5.5.9 of IPC-TM-650.

[0064] Dielectric loss factor tangent (Df): The dielectric loss factor tangent at 10 GHz was determined using the plate method according to section 2.5.5.9 of IPC-TM-650.

[0065] Copper foil peel strength: Measured at room temperature (approximately 25°C) according to the method described in section 2.4.9 of IPC-TM-650.

[0066] Table 1. Resin composition / parts by weight of copper-clad laminates in Examples 4-6 and Comparative Examples 1-2

[0067] Table 2 Performance Test Table

[0068] The molecular structure of the polyaniline-type maleimide BMI-2300 in the formulation of Comparative Example 1 has the following problems: 1. The synergistic polarization effect between the aromatic ring and the nitrogen atom in the molecular structure. Specifically: Synergistic effect of strong conjugated system and polar group - The π-electron conjugated system of aromatic ring is prone to electronic polarization in an electric field, and the nitrogen atom directly connected to it (N atom in maleimide ring) further strengthens the dipole moment of the molecule. The combination of this conjugated system with polar group (such as carbonyl C=O) significantly enhances the polar strength of the molecular chain. The lack of depolarizing groups—the absence of nonpolar groups to counteract the dipole effect—leads to dipole-dipole interactions dominating dielectric behavior and exacerbating energy loss during polarization. The polarization relaxation is intensified under high frequency and high temperature conditions. Under the high frequency of 10 GHz, the orientation polarization and dipole relaxation process of the dipole are significantly activated, resulting in Df of the formulation system reaching more than 0.004 and Dk reaching more than 3.5.

[0069] 2. Defects in molecular structure regularity and compatibility: The molecule is dominated by a highly rigid benzene ring skeleton and polar imide five-membered ring end caps, leading to: Significant crystallization tendency—the regular arrangement of aromatic and imide rings enhances the stacking order of molecular chains, making it easy to form thermodynamically unstable phases in nonpolar solvents (such as hydrocarbon solvents) and / or hydrocarbon resin systems, triggering precipitation during mixing and curing. Phase separation is exacerbated – the polarity mismatch between polar monomers and non-polar matrices (such as polyolefin resins) leads to a clear phase interface during mixing, triggering micro-agglomeration and weakening the interfacial bonding strength.

[0070] 3. Deterioration of mechanical properties: Phase separation leads to the formation of voids or weak bonding areas at the interface between the resin and the copper foil, which reduces the peel strength of the copper foil (peel force < 0.7 N / mm).

[0071] In comparison, Examples 1-3 of this invention benefit from a molecular design that combines rigidity and flexibility. The molecular structure possesses the synergistic effect of a rigid imide ring and flexible active hydrocarbon side chains. The rigid skeleton ensures high-temperature stability, while the flexible segments effectively alleviate internal stress and suppress precipitation tendency, while maintaining excellent processing fluidity. This rigid-flexible balanced design, applied in the system as shown in Examples 4-6, achieves multiple synergistic properties, including high heat resistance (Tg > 300℃, CTE < 1%), low dielectric loss ( < 0.002), copper foil peel strength ( > 1.0 N / mm), and excellent compatibility and anti-precipitation properties. The nonpolar groups on the aromatic ring fully counteract the dipole effect, also endowing the material with superior dielectric properties (Df < 0.002, Dk < 3.0).

[0072] The multifunctional PPO / hydrocarbon resin system of Comparative Example 2 has excellent dielectric loss (<0.002), good heat resistance (Tg>250℃, CTE<2%) and good peel strength (>0.5N / mm).

[0073] Based on Comparative Example 2, the multifunctional imide resin of this invention (as in Examples 4–6) is introduced. While maintaining high component compatibility (clear and uniform adhesive solution, without precipitation or stratification) and excellent dielectric loss (<0.002), the heat resistance is further improved to Tg > 300℃, CTE < 1%, and peel strength is enhanced to > 1.0 N / mm, resulting in significantly optimized overall performance. The improved system, while maintaining low dielectric loss (suitable for 5G / 6G high-frequency scenarios), significantly expands its application potential in high-reliability fields such as aerospace microwave circuit boards and automotive electronic high-temperature packaging through breakthroughs in heat resistance and peel strength.

[0074] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A polyfunctional imide resin, characterized in that, The general structural formula is as follows: ； Where n is an integer between 1 and 60; R1 is C2-C 20 Alkyl, C3-C 20 cycloalkyl, C6-C 30 Aryl, nitrogen- and / or oxygen-substituted C2-C 20 Alkyl groups and C3-C atoms containing nitrogen and / or oxygen elements 20 One or more heterocyclic groups; R2 is C2-C 20 Alkyl, C3-C 20 cycloalkyl, C6-C 30 Aryl, nitrogen- and / or oxygen-substituted C2-C 20 Alkyl groups and C3-C atoms containing nitrogen and / or oxygen elements 20 One or more heterocyclic groups; R3 is C2-C 20 Contains unsaturated carbon-bonded hydrocarbon groups, C3-C 20 Contains unsaturated carbon-bonded cyclic hydrocarbon groups, C6-C 30 C2-C containing unsaturated carbon-bonded aryl groups, and containing nitrogen and / or oxygen elements. 20 Heterocyclic groups containing unsaturated carbon bonds and C3-C groups substituted with nitrogen and / or oxygen elements. 20 A group consisting of one or more unsaturated carbon-bonded hydrocarbon groups.

2. The method for preparing a multifunctional imide resin according to claim 1, characterized in that, The raw materials for the multifunctional imide resin include cycloolefin succinic anhydride, olefin compound, first solvent, second solvent, initiator, end-capping promoter, acid catalyst, and active hydrocarbon primary amine containing reactive carbon bonds. The molar ratio of cycloolefin succinic anhydride to olefin compound is 0.9~1.1:0.1~3, and the molar ratio of olefin succinic anhydride to active hydrocarbon primary amine is 0.9~1.1:1~2. The preparation method includes the following steps: A mixture was prepared by dissolving cycloolefin succinic anhydride and olefin compounds in a first solvent; The mixture is added dropwise to a second solvent at a temperature of 50-100℃ for 1-5 hours, and the reaction is continued for 1-5 hours. After the addition is completed, an initiator and a capping accelerator are added and the reaction is continued for 1-5 hours to obtain a cycloolefin succinic anhydride-olefin compound copolymer solution. A solution of cycloolefin succinic anhydride-olefin compound copolymer was reacted with an active hydrocarbon primary amine at 20-40°C for 2-5 hours to obtain maleimide acid. Add an acidic catalyst to maleimide acid, reflux at 60~130℃ for 2h~6h to dehydrate and close the ring, wash with water, heat to 60~160℃ and vacuum for 1~5h to remove solvent, and obtain a multifunctional imide resin.

3. The preparation method according to claim 2, characterized in that: The olefinic compound is C2-C. 100 Alkene-based compounds that are monofunctional or polyfunctional, containing nitrogen, phosphorus, and oxygen elements or not containing nitrogen, phosphorus, and oxygen elements; The olefinic cyclic dicarboxylic anhydride is C2-C. 50 olefinic cyclic dicarboxylic anhydrides; The active hydrocarbon-based primary amine is C2-C. 50 The active hydrocarbon primary amine, wherein the active hydrocarbon group includes alkenes, alkynes, cyclopropanes or benzocyclobutene.

4. The preparation method according to claim 2, characterized in that: The initiator is an azo radical initiator or a peroxide radical initiator, and the amount used is 3% to 8% of the total mass of the cycloolefin succinic anhydride and the olefin compound.

5. The preparation method according to claim 2, characterized in that: The second solvent is a hydrocarbon containing a benzene ring with 7-10 carbon atoms, and the amount used is 300% to 500% of the total mass of the cycloalkenyl succinic anhydride and olefinic compound.

6. The preparation method according to claim 2, characterized in that: The end-capping accelerator is a phenylalkane, which is selected from one or a combination of several of 2,3-dimethyl-2,3-diphenylbutane, diphenylmethane, 3,4-dimethyl-3,4-diphenylhexane, 1,3-diphenylbutane, 1,4-diphenylbutane, diphenylethane, and diphenylpropane, and is used in an amount of 0.5% to 2% of the total mass of the cycloalkenyl succinic anhydride and the olefin compound.

7. The preparation method according to claim 2, characterized in that: The first solvent is a mixture of hydrocarbon solvents containing benzene rings with 7-10 carbon atoms and ketone solvents with 3-8 carbon atoms, wherein the mass ratio of ketone solvent to hydrocarbon solvent is 5:1, and the amount of the first solvent is 30% to 100% of the total mass of cycloalkenyl succinic anhydride and alkene compounds.

8. The preparation method according to claim 2, characterized in that: The acidic catalyst is p-toluenesulfonic acid, and its dosage is 5% to 15% of the total mass of cycloolefin succinic anhydride, olefinic compound and active hydrocarbon primary amine.

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