An epoxy resin composition and its application

Abstract

This invention provides an epoxy resin composition and its application. The epoxy resin composition comprises an epoxy resin, a curing system, and a modified boron nitride. The modified boron nitride is prepared by a method comprising: mixing boron nitride with a sintering aid, followed by sintering and crushing to obtain the modified boron nitride. This invention involves sintering and crushing boron nitride with a specific type and amount of sintering aid. Through the design of the modification method, the modified boron nitride achieves a high filling ratio in the epoxy resin. The epoxy resin composition containing it achieves high thermal conductivity, high peel strength, and excellent adhesion properties, thereby enabling the metal foil laminate to achieve excellent overall performance in terms of high thermal conductivity and high reliability.

Description

Technical Field

[0001] This invention belongs to the field of copper clad laminate technology, specifically relating to an epoxy resin composition and its application. Background Technology

[0002] As electronic products become increasingly dense, multifunctional, and "lightweight, thin, and small," the power consumption of components is increasing, and the component assembly density and integration on circuit boards are becoming higher. This results in more and more heat being dissipated per unit area of ​​the circuit board during operation. If the heat dissipation of the substrate is poor, the temperature of the components on the circuit board will become too high, reducing the overall stability and reliability of the device, and even causing product failure and shortening its lifespan. Therefore, to ensure the operational stability of electronic components, higher requirements are placed on the heat dissipation performance of the board material.

[0003] To improve the thermal conductivity of the substrate, high thermal conductivity materials are typically introduced during the preparation of the dielectric layer and copper clad laminate, such as resins and fillers with good thermal conductivity. Since the types of resins with good thermal conductivity are relatively limited and their cost is high, adding thermally conductive fillers is the primary method. For example, CN102993996A discloses a high thermal conductivity adhesive film for copper clad laminates, whose raw materials include: 25-35 parts epoxy resin, 65-75 parts thermally conductive filler, 30-40 parts solvent, and 10-20 parts curing agent. CN116080213A discloses a high thermal conductivity and high heat resistance CEM-3 copper clad laminate, wherein the raw materials for preparing the core material include: 10-50% long-chain polymer epoxy resin, 10-40% solid phenolic resin, 40-60% brominated epoxy resin, 0.10-0.80% imidazole catalyst, 10-30% inorganic filler, 10-60% flame retardant filler, and 40-70% high thermal conductivity powder; the raw materials for preparing the surface material include the following weight percentages of raw materials: 10-40% phosphorus-containing epoxy resin, 40-60% brominated epoxy resin, 0.10-0.80% imidazole catalyst, 0.1-1% dicyandiamide, and 10-60% flame retardant filler; wherein the inorganic filler is one or a mixture of several of spherical silica powder and titanium dioxide, and the main component of the high thermal conductivity powder is nitrogen aluminum oxide. CN103694644A discloses an epoxy resin composition comprising, by weight, the following components: 90-110 parts epoxy resin, 10-50 parts thermoplastic resin, 1-100 parts curing agent, 0.05-5 parts curing accelerator, 1-10 parts additives, and 20-500 parts thermally conductive filler; wherein the thermally conductive filler is one or more of zinc oxide, magnesium oxide, aluminum oxide, bismuth oxide, beryllium oxide, magnesium hydroxide, aluminum hydroxide, silicon dioxide, iron oxide, boron nitride, silicon nitride, silicon carbide, diamond, and trisilicon tetranitride; this epoxy resin composition can improve the thermal conductivity and insulation of composite materials and copper-clad laminates.

[0004] Currently, the thermally conductive fillers used in copper-clad laminate (CCL) materials mainly include alumina, aluminum nitride, boron nitride, boron oxide, and silicon carbide. Among them, boron nitride, as a filler with excellent thermal conductivity, has great potential in the field of thermal conductive materials. However, boron nitride has a lamellar structure and a large specific surface area, which prevents it from being filled in large quantities into the resin, greatly weakening its ability to improve the thermal conductivity of composite materials. Moreover, increasing the amount of thermally conductive filler can lead to poor adhesion between the adhesive layer and the copper foil and metal substrate, thereby weakening a series of properties of the CCL, such as heat resistance and voltage resistance, resulting in a decrease in the reliability of the substrate.

[0005] Therefore, developing a composite material with high thermal conductivity and excellent bonding properties is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an epoxy resin composition and its application. Through the design of the preparation method, modified boron nitride with high thermal conductivity and high filling ratio is obtained, so that the epoxy resin composition containing it has high thermal conductivity, high peel strength and excellent adhesion properties, thereby enabling the metal foil laminate to achieve excellent comprehensive performance in terms of high thermal conductivity and high reliability.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an epoxy resin composition comprising an epoxy resin, a curing system, and a combination of modified boron nitride.

[0009] The modified boron nitride is prepared by the following method, which includes: mixing boron nitride and a sintering aid, followed by sintering and crushing to obtain the modified boron nitride.

[0010] The sintering aid includes any one or a combination of at least two of calcium oxide, magnesium oxide, silicon oxide, yttrium oxide, niobium oxide, and potassium feldspar; the sintering aid comprises 1-10% by mass, based on the total mass of boron nitride and the sintering aid being 100%.

[0011] This invention involves sintering and crushing boron nitride and a specific type of sintering aid at high temperature to obtain modified boron nitride particles. Under the synergistic effect of the sintering aid and sintering, the filling ratio of modified boron nitride particles in epoxy resin can be significantly increased. This allows the epoxy resin composition to achieve higher thermal conductivity while also having high peel strength and excellent adhesion, thereby significantly improving the overall performance of the metal foil laminate in terms of heat dissipation and reliability.

[0012] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0013] Preferably, the boron nitride comprises hexagonal boron nitride and / or cubic boron nitride, and more preferably hexagonal boron nitride.

[0014] In this invention, the total mass of the boron nitride and sintering aid is 100%, and the mass of the sintering aid is 1-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0015] This invention involves mixing specific types and amounts of sintering aids with boron nitride, followed by sintering and crushing to obtain modified boron nitride. This overcomes the drawback of lamellar boron nitride, which cannot be extensively filled, resulting in insufficient thermal conductivity in the material. The modified boron nitride exhibits excellent thermal conductivity and a high filling ratio in epoxy resin, enabling epoxy resin compositions containing it to possess both high thermal conductivity and high peel strength. If the amount of sintering aid is <1%, it is difficult to effectively modify boron nitride and increase its filling ratio in the resin; if the amount of sintering aid is >10%, the thermal conductivity of both the modified boron nitride and the epoxy resin composition containing it will decrease.

[0016] Preferably, the epoxy resin includes any one or a combination of at least two of the following: bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic resin, phosphorus-containing epoxy resin, isocyanate-modified epoxy resin, phenolic epoxy resin, biphenyl epoxy resin, dicyclopentadiene type epoxy resin, naphthalene-containing epoxy resin, alicyclic epoxy resin, and brominated epoxy resin.

[0017] Preferably, the isocyanate-modified epoxy resin includes MDI (diphenylmethane diisocyanate)-modified epoxy resin.

[0018] Preferably, the epoxy resin composition contains 8-70% by mass of epoxy resin, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, or 65%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list all the specific values ​​included in the range, but 9-50% is further preferred.

[0019] Preferably, the mass percentage of the cured system in the epoxy resin composition is 0.01-30%, for example, it can be 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 25% or 28%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0020] Preferably, the curing system includes a curing agent and / or an accelerator.

[0021] Preferably, the curing agent includes any one or a combination of at least two of the following: phenolic resin, cyanate ester resin, reactive ester, modified polyphenylene ether resin, maleimide resin, acid anhydride curing agent, amine curing agent, and benzoxazine resin.

[0022] Preferably, the phenolic resin includes any one or a combination of at least two of the following: bisphenol A type phenolic resin, phosphorus-containing phenolic resin, phenolic resin, biphenyl type phenolic resin, dicyclopentadiene type phenolic resin, and naphthol-containing phenolic resin.

[0023] Preferably, the modified polyphenylene ether resin includes any one or a combination of at least two of hydroxyl-terminated polyphenylene ether resin, amino-terminated polyphenylene ether resin, and anhydride-terminated polyphenylene ether resin.

[0024] Preferably, the curing agent in the epoxy resin composition has a mass percentage content of ≤20%, for example, it can be 0, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 15%, 16% or 18%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0025] Preferably, the promoter comprises any one or a combination of at least two of imidazole compounds, organic complexes, tertiary amines, tertiary phosphine, and quaternary ammonium salts, with imidazole compounds being more preferred.

[0026] It should be noted that the imidazole compounds, as accelerators, can simultaneously play the roles of curing epoxy resin and promoting curing.

[0027] Preferably, the imidazole compound includes any one or a combination of at least two of 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, 2-isopropylimidazole, 2-phenyl-4-methylimidazole, 2-dodecylimidazole, and 1-cyanoethyl-2-methylimidazole.

[0028] Preferably, the accelerator in the epoxy resin composition has a mass percentage content of ≤8%, for example, it can be 0, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, or 7.5%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 0.01-6% is further preferred.

[0029] Preferably, the average particle size of the modified boron nitride is 0.1-30 μm, for example, it can be 0.2 μm, 0.5 μm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm or 28 μm, as well as specific particle sizes between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific particle sizes included in the range.

[0030] In this invention, the average particle size can be understood as D. 50 Particle size data can be obtained using an MS3000 Malvern laser particle size analyzer.

[0031] In this invention, the mass percentage of modified boron nitride in the epoxy resin composition can be adjusted according to the requirements of thermal conductivity, processability of the board, peel strength, reliability and other properties, and can be 10-92%, more preferably 20-92%.

[0032] Preferably, the mass percentage of modified boron nitride in the epoxy resin composition is 30-92%, for example, it can be 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90%, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 50-90% is further preferred.

[0033] As a preferred embodiment of the present invention, the modified boron nitride content in the epoxy resin composition is 30-92% by mass, more preferably 50-90%, thereby giving the epoxy resin composition and the metal foil laminate prepared therefrom high thermal conductivity, high peel strength, and excellent reliability. If the modified boron nitride content is too low, the thermal conductivity of the material will decrease; if the modified boron nitride content is too high, the processability of the epoxy resin composition will deteriorate, making it difficult to produce qualified boards.

[0034] Preferably, in the method for preparing modified boron nitride, the mixed raw materials also include other metal oxides.

[0035] In this invention, "other metal oxides" refers to metal oxides that are different from sintering aids.

[0036] Preferably, the other metal oxides include aluminum oxide and / or beryllium oxide.

[0037] Preferably, based on the total mass of the boron nitride, sintering aid, and other metal oxides as 100%, the mass of the other metal oxides is ≤10%, for example, it can be 0, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but more preferably 1-10%.

[0038] Preferably, the mixing method includes physical dry mixing.

[0039] Preferably, the mixing time is 0.1-3h, for example, it can be 0.2h, 0.4h, 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h, 2h, 2.2h, 2.5h or 2.8h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0040] Preferably, the sintering is carried out in an inert atmosphere.

[0041] Preferably, the inert atmosphere includes a nitrogen atmosphere and / or an argon atmosphere.

[0042] Preferably, the sintering method includes a single-stage sintering method or a two-stage sintering method.

[0043] It should be noted that, regardless of whether it is a one-stage sintering method or a two-stage sintering method, the sintering process is carried out in an inert atmosphere (preferably a nitrogen atmosphere and / or an argon atmosphere).

[0044] Preferably, the sintering temperature of the single-stage sintering method is 700-2000℃, for example, it can be 800℃, 900℃, 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, 1600℃, 1700℃, 1800℃ or 1900℃, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0045] Preferably, the sintering pressure of the single-stage sintering method is 1-10 GPa, for example, it can be 2 GPa, 3 GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa, 8 GPa or 9 GPa, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0046] Preferably, the sintering time of the single-stage sintering method is 2-8 hours, for example, it can be 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours or 7.5 hours, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0047] As a preferred technical solution of the present invention, as a single-stage sintering method, by carrying out sintering in an inert atmosphere and controlling the sintering temperature to be 700-2000℃, the pressure to be 1-10GPa, and the time to be 2-8h, the modified boron nitride can be further improved in its filling ratio in epoxy resin while having high thermal conductivity.

[0048] Preferably, the two-stage sintering method includes: mixing boron nitride, sintering aids, and optionally other metal oxides, and then subjecting the mixture to a first sintering and a first crushing to obtain primary particles; and subjecting the primary particles to a second sintering and a second crushing to obtain the modified boron nitride.

[0049] Preferably, the temperature of the first sintering is 300-700℃, for example, it can be 350℃, 400℃, 450℃, 500℃, 550℃, 600℃ or 650℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0050] Preferably, the pressure of the first sintering is 1-10 GPa, for example, it can be 2 GPa, 3 GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa, 8 GPa or 9 GPa, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0051] Preferably, the first sintering time is 1-8 hours, for example, it can be 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours or 7.5 hours, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0052] Preferably, the average particle size of the primary particles is 0.1-50 μm, for example, it can be 0.2 μm, 0.5 μm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, 35 μm, 40 μm or 45 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0053] Preferably, the second sintering temperature is 700-2000℃, for example, it can be 800℃, 900℃, 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, 1600℃, 1700℃, 1800℃ or 1900℃, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0054] Preferably, the second sintering time is 2-8 hours, for example, it can be 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours or 7.5 hours, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0055] As another preferred embodiment of the present invention, a mixture comprising boron nitride, a sintering aid, and optionally other metal oxides is subjected to two-stage sintering. The first sintering is carried out under high temperature and high pressure (300-700°C, 1-10 GPa, 1-8 h); the second sintering is carried out at high temperature (700-2000°C, 2-8 h), without the need for additional pressure. Through the design and optimization of the two sintering processes, the filling ratio of the modified boron nitride in the epoxy resin can be further increased.

[0056] Preferably, the crushing method (first crushing, second crushing) includes ball milling, for example, wet ball milling.

[0057] Preferably, the ball milling speed is 500-5000 rpm, for example, it can be 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm or 4500 rpm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0058] Preferably, the ball milling time is 0.5-6 hours, for example, it can be 0.8 hours, 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, 4 hours, 4.2 hours, 4.5 hours, 4.8 hours, 5 hours, or 5.5 hours, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0059] Preferably, the epoxy resin composition further includes any one or a combination of at least two of the following: filler, flame retardant, and coupling agent.

[0060] Preferably, the filler comprises any one or a combination of at least two of the following: silicon dioxide, titanium dioxide, barium titanate, strontium titanate, magnesium titanate, calcium titanate, barium strontium titanate, barium calcium titanate, lead titanate, lead zirconate titanate, lanthanum lead zirconate titanate, barium lanthanum titanate, barium zirconate titanate, hafnium dioxide, lead magnesium niobate, barium magnesium niobate, lithium niobate, potassium niobate, strontium aluminum tantalate, potassium tantalate, barium strontium niobate, barium strontium niobate, barium barium niobate, barium titanium barium niobate, strontium bismuth tantalate, bismuth titanate, rubidium barium titanate, copper titanate, and lead titanate-lead magnesium niobate.

[0061] Preferably, the average particle size (D) of the filler is 50 The particle size is 0.01-50 μm, for example, it can be 0.05 μm, 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range. It is further preferred to be 0.01-30 μm, and even more preferred to be 0.01-10 μm.

[0062] Preferably, the filler content in the epoxy resin composition is ≤20% by mass, for example, it can be 0, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 15%, 16% or 18%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0063] Solvents may also be added to the above-mentioned epoxy resin composition. The amount of solvent added is selected by those skilled in the art based on experience and process requirements, so that the epoxy resin composition reaches a suitable viscosity for use, facilitating impregnation, coating, etc. During subsequent drying, semi-curing, or complete curing stages, the solvent in the epoxy resin composition will partially or completely evaporate.

[0064] On the other hand, the present invention provides a resin adhesive comprising the epoxy resin composition and solvent as described in the first aspect.

[0065] For example, the solvent includes any one or a combination of at least two of ketone solvents, alcohol solvents, aromatic hydrocarbon solvents, ester solvents, and nitrogen-containing solvents.

[0066] The solvent used in this invention is not particularly limited, and can generally be ketones such as acetone, butanone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and mesitylene; esters such as ethyl acetate, butyl acetate, and ethoxyethyl acetate; alcohols such as methanol, ethanol, and butanol; ethers such as ethyl cellosolve, butyl cellosolve, ethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, carbitol, and butyl carbitol; and nitrogen-containing solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. The solvent can be used alone or in combination of two or more.

[0067] The epoxy resin composition provided by the present invention is prepared by the following method, the preparation method comprising: mixing and dispersing each component in the epoxy resin composition evenly to obtain the epoxy resin composition.

[0068] In a second aspect, the present invention provides a prepreg comprising a reinforcing material and an epoxy resin composition as described in the first aspect attached to the reinforcing material.

[0069] Preferably, the epoxy resin composition is attached to the reinforcing material after impregnation and drying.

[0070] For example, the prepreg is prepared by impregnating the reinforcing material with the resin solution of the epoxy resin composition and then drying it to obtain the prepreg.

[0071] Preferably, the drying temperature is 100-180℃, for example, it can be 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃ or 175℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 115-175℃ is further preferred.

[0072] Preferably, the drying time is 1-30 min, for example, it can be 2 min, 5 min, 8 min, 10 min, 15 min, 20 min or 25 min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 2-15 min is further preferred.

[0073] Thirdly, the present invention provides a thermally conductive resin film, wherein the material of the thermally conductive resin film comprises the epoxy resin composition as described in the first aspect.

[0074] Preferably, the thermally conductive resin film is obtained by coating the epoxy resin composition onto a release material and then drying and / or semi-curing it.

[0075] On the other hand, the present invention provides a resin-coated copper foil comprising a copper foil layer and a resin layer, wherein the material of the resin layer comprises the epoxy resin composition as described in the first aspect.

[0076] Preferably, the resin-coated copper foil is obtained by coating the epoxy resin composition onto a copper foil and then drying and / or semi-curing it.

[0077] Fourthly, the present invention provides a metal foil laminate, the metal foil laminate comprising a metal foil, and at least one of the prepreg as described in the second aspect and the thermally conductive resin film as described in the third aspect.

[0078] Preferably, the metal foil in the metal foil-coated laminate includes any one or a combination of at least two of copper foil, aluminum foil, nickel foil, and alloy foil.

[0079] Preferably, the metal foil is copper foil, and the metal foil laminate is copper clad laminate.

[0080] Preferably, the number of prepreg sheets in the metal foil laminate is 1-20, for example, 2, 3, 5, 7, 9, 10, 11, 13, 15, 17 or 19, and the specific point values ​​between the above point values ​​are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0081] For example, the method for preparing the metal foil laminate includes: pressing a metal foil onto one or both sides of a prepreg and curing it to obtain the metal foil laminate; or, stacking at least two prepregs into a laminate, then pressing a metal foil onto one or both sides of the laminate and curing it to obtain the metal foil laminate.

[0082] Preferably, the curing is carried out in a press.

[0083] Preferably, the curing temperature is 170-280℃, such as 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃ or 270℃, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0084] Preferably, the curing pressure is 1-10 MPa, for example 1.5 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa or 9 MPa, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0085] Preferably, the curing time is 30-300 min, such as 40 min, 50 min, 60 min, 80 min, 100 min, 120 min, 150 min, 180 min, 200 min, 220 min, 240 min, 260 min or 280 min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0086] On the other hand, the present invention provides a printed circuit board comprising at least one of the prepreg as described in the second aspect, a thermally conductive resin film as described in the third aspect, and a metal foil laminate as described in the fourth aspect.

[0087] Compared with the prior art, the present invention has the following beneficial effects:

[0088] (1) In the epoxy resin composition provided by the present invention, boron nitride is sintered with a specific type and amount of sintering aid and then crushed. Through the design of the modification method, the modified boron nitride has a high filling ratio in the epoxy resin. The epoxy resin composition containing it has high thermal conductivity, high peel strength and excellent adhesion performance, thereby achieving excellent comprehensive effect of high thermal conductivity and high reliability in the metal foil laminate.

[0089] (2) Through the design and optimization of the components and proportions of the epoxy resin composition, the present invention enables the copper clad laminate containing it to have a thermal conductivity ≥4.86W / m·k and a peel strength ≥0.71N / mm, while also possessing excellent thermal conductivity and heat dissipation performance, interlayer bonding strength and reliability. Detailed Implementation

[0090] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0091] The preparation method of the modified boron nitride is illustrated below with specific preparation examples, but the preparation method of the modified boron nitride is not limited to these preparation examples.

[0092] In the following preparation examples, boron nitride, sintering aids, and other metal oxides are all commercially available chemicals; among them, boron nitride has a layered structure and was purchased from 3M, CFP003.

[0093] Preparation Examples 1-6

[0094] Modified boron nitride AF is prepared by the following method:

[0095] Boron nitride, sintering aid, and optionally other metal oxides were weighed according to the proportions shown in Table 1 by mass, and physically dry-mixed for 1 hour to obtain a mixture. The mixture was added to a mold and sintered in a nitrogen atmosphere according to the temperature, pressure, and time shown in Table 1 to obtain a sintered product. The sintered product was a block sample, which was placed in a ball mill for wet ball milling at a speed of 3000 rpm for 1-5 hours. The zirconium beads were mixed with a particle size of 1-10 mm. After ball milling, the product was dried to obtain modified boron nitride particles. The preparation of modified boron nitride with different particle sizes was achieved by controlling the ball milling time.

[0096] Table 1

[0097]

[0098] In Table 1, the amounts of boron nitride (BN), sintering aids, and other metal oxides are expressed in "parts" (parts by mass), with "--" indicating that the component was not added. The average particle size of the modified boron nitride was measured using laser diffraction, with a Malvern laser particle size analyzer, model MS3000.

[0099] Preparation Example 7

[0100] Modified boron nitride G is prepared as follows:

[0101] 96 parts by weight of boron nitride and 4 parts by weight of magnesium oxide were weighed and physically dry-mixed for 1 hour to obtain a mixture. The mixture was added to a grinding mold and sintered at 700°C and 8 GPa for 6 hours in a nitrogen atmosphere to obtain a blocky first sintered product. The product was then wet-milled in a ball mill at 3000 rpm for 2 hours, with zirconium beads of 1-10 mm particle size. After ball milling, the product was dried to obtain primary particles. The primary particles were placed in a high-temperature furnace and sintered at 1800°C for 6 hours in a nitrogen atmosphere. The sintered product was then wet-milled in a ball mill and dried to obtain modified boron nitride G with an average particle size of 15 μm.

[0102] The epoxy resin composition and its application described in this invention will be described in detail below with several examples, but the epoxy resin composition and its application are not limited to these examples.

[0103] In the following examples, materials for which no preparation method is provided are commercially available chemicals, as detailed in the table below:

[0104] category source Epoxy Resin A, ZX1059 Nippon Steel Corporation Brominated epoxy resin, BEB531A80P Chang Chun Chemical Company, Taiwan Phenoxy resin, YP-50EK35 Nippon Steel Corporation Curing agent: Phenolic resin, SH4064 Shandong Shengquan Co., Ltd. Accelerator: 2-Methylimidazole (2-MI) BASF Modified boron nitride AG Preparation Examples 1-7

[0105] Examples 1-7, Comparative Examples 1-3

[0106] An epoxy resin composition, the types and amounts of each component are shown in Table 2, and the unit of amount of each component is "parts" (parts by mass).

[0107] A prepreg comprising the epoxy resin composition and a copper-clad laminate are prepared by the following method:

[0108] (1) Mix each component of the epoxy resin composition with solvent (ethylene glycol methyl ether) according to the formula amount, disperse evenly at room temperature to prepare a glue solution with a solid content of 80%; impregnate the glue solution with fiberglass cloth, place it in an oven at 155°C and bake for 5 minutes to obtain a prepreg with a thickness of 5mil.

[0109] (2) Six prepreg sheets are stacked together, copper foil is stacked on both sides, and the copper-clad laminate is laminated and cured at 210°C and 5MPa pressure for 2 hours in a hot press to obtain the copper-clad laminate.

[0110] The copper-clad laminate was subjected to performance testing, and the specific method is as follows:

[0111] (1) Thermal conductivity: The thermal conductivity of the sheet was tested according to the test method in standard ASTM-D5470;

[0112] (2) Peel strength: The peel strength of the board was tested according to the test conditions in IPC-TM-650 2.4.8.

[0113] The performance test data is shown in Table 2.

[0114] Table 2

[0115]

[0116]

[0117] According to the performance test data in Table 2, the present invention combines modified boron nitride prepared by a specific method with an epoxy resin system, so that the epoxy resin composition and the copper clad laminate prepared therefrom have high thermal conductivity and high peel strength. Among them, the thermal conductivity of Examples 1-5 is 4.86-14.7 W / m·K and the peel strength is 0.71-1.35 N / mm, which have excellent comprehensive performance.

[0118] In Example 6, the amount of modified boron nitride used was too small, resulting in a decrease in the thermal conductivity of the copper-clad laminate; in Example 7, the amount of modified boron nitride used was too large, which would lead to poor processability of the composition and make it impossible to prepare a qualified product.

[0119] A comparison of Example 4 with Comparative Examples 1-3 reveals that in Comparative Example 1, the amount of sintering aid used in the preparation of modified boron nitride E was too small, resulting in an insignificant modification effect. The modified boron nitride E still could not achieve a high filling ratio, leading to poor processability and the inability to produce a qualified product. Similarly, in Comparative Example 3, the use of unmodified boron nitride filler also resulted in an inability to achieve high filling levels and produce a qualified product. In Comparative Example 2, the use of excessive sintering aids in the modified boron nitride F affected the thermal conductivity of the material, leading to a significant decrease in the thermal conductivity of the sheet material.

[0120] The applicant declares that the epoxy resin composition and its application of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An epoxy resin composition for printed circuit boards, characterized in that, The epoxy resin composition comprises a combination of epoxy resin, a curing system, and modified boron nitride; The modified boron nitride is prepared by the following method, which includes: physically dry mixing boron nitride and sintering aid, followed by sintering and crushing to obtain the modified boron nitride; The sintering aids include any one or a combination of at least two of the following: calcium oxide, magnesium oxide, silicon oxide, yttrium oxide, niobium oxide, and potassium feldspar. With the total mass of the boron nitride and sintering aid being 100%, the mass of the sintering aid is 1-10%. The modified boron nitride content in the epoxy resin composition is 30-92% by mass; The sintering method includes a single-stage sintering method or a two-stage sintering method; The sintering temperature of the first-stage sintering method is 700-2000℃, the sintering pressure is 1-10 Gpa, and the sintering time is 2-8 h; The two-stage sintering method includes: mixing boron nitride and a sintering aid, and then subjecting the mixture to a first sintering and a first crushing to obtain primary particles; and subjecting the primary particles to a second sintering and a second crushing to obtain the modified boron nitride. The first sintering temperature is 300-700℃, the pressure is 1-10 GPa, and the time is 1-8 h; The second sintering temperature is 700-2000℃, and the time is 2-8 h; The sintering is carried out in an inert atmosphere.

2. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin includes any one or a combination of at least two of the following: bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic resin, phosphorus-containing epoxy resin, isocyanate-modified epoxy resin, phenolic epoxy resin, biphenyl epoxy resin, dicyclopentadiene type epoxy resin, naphthalene-containing epoxy resin, alicyclic epoxy resin, and brominated epoxy resin.

3. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition contains 8-70% epoxy resin by mass.

4. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition contains 8-50% epoxy resin by mass.

5. The epoxy resin composition according to claim 1, characterized in that, The curing system includes a curing agent and / or an accelerator.

6. The epoxy resin composition according to claim 1, characterized in that, The mass percentage of the cured system in the epoxy resin composition is 0.01-30%.

7. The epoxy resin composition according to claim 5, characterized in that, The curing agent includes any one or a combination of at least two of the following: phenolic resin, cyanate ester resin, reactive ester, modified polyphenylene ether resin, maleimide resin, acid anhydride curing agent, amine curing agent, and benzoxazine resin.

8. The epoxy resin composition according to claim 7, characterized in that, The phenolic resin includes any one or a combination of at least two of the following: bisphenol A type phenolic resin, phosphorus-containing phenolic resin, phenolic resin, biphenyl type phenolic resin, dicyclopentadiene type phenolic resin, and naphthol-containing phenolic resin.

9. The epoxy resin composition according to claim 5, characterized in that, The promoter includes any one or a combination of at least two of imidazole compounds, organic complexes, tertiary amines, tertiary phosphine, and quaternary ammonium salts.

10. The epoxy resin composition according to claim 9, characterized in that, The promoters include imidazole compounds.

11. The epoxy resin composition according to claim 10, characterized in that, The imidazole compounds include any one or a combination of at least two of the following: 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, 2-isopropylimidazole, 2-phenyl-4-methylimidazole, 2-dodecylimidazole, and 1-cyanoethyl-2-methylimidazole.

12. The epoxy resin composition according to claim 5, characterized in that, The accelerator in the epoxy resin composition has a mass percentage content of ≤8%.

13. The epoxy resin composition according to claim 1, characterized in that, The modified boron nitride has an average particle size of 0.1-30 μm.

14. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin composition contains 50-90% by mass of modified boron nitride.

15. The epoxy resin composition according to claim 1, characterized in that, The mixed raw materials also include other metal oxides; The other metal oxides include aluminum oxide and / or beryllium oxide; The total mass of the boron nitride, sintering aid, and other metal oxides is 100%, and the mass of the other metal oxides is 1-10%.

16. The epoxy resin composition according to claim 1, characterized in that, The inert atmosphere includes a nitrogen atmosphere and / or an argon atmosphere.

17. A prepreg, characterized in that, The prepreg comprises a reinforcing material and an epoxy resin composition as described in any one of claims 1-16 attached to the reinforcing material.

18. The prepreg according to claim 17, characterized in that, The epoxy resin composition is attached to the reinforcing material after impregnation and drying.

19. A thermally conductive resin film, characterized in that, The material of the thermally conductive resin film includes the epoxy resin composition as described in any one of claims 1-16.

20. The thermally conductive resin film according to claim 19, characterized in that, The thermally conductive resin film is prepared by coating the epoxy resin composition onto a release material and then drying and / or semi-curing it.

21. A metal foil-coated laminate, characterized in that, The metal foil laminate includes a metal foil and at least one of the prepreg as described in claim 17 or 18 and the thermally conductive resin film as described in claim 19 or 20.

22. A printed circuit board, characterized in that, The printed circuit board includes at least one of the prepreg as described in claim 17 or 18, the thermally conductive resin film as described in claim 19 or 20, and the metal foil laminate as described in claim 21.

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