Modified epoxy resin composition, composite adhesive film, copper-clad plate and application thereof

Abstract

The invention discloses a modified epoxy resin composition which comprises 5-8 parts of epoxy resin, 17-36 parts of modified polyphenyl ether, 22.5-55 parts of modified filler, 0.5-2 parts of a curing agent and 200-300 parts of a solvent. The invention further discloses application of the modified epoxy resin composition, a composite adhesive film comprising the composition, a copper-clad plate and application of the composite adhesive film and the copper-clad plate. The modified epoxy resin composition disclosed by the invention is applied to preparation of a copper-clad plate, and a product has excellent heat-conducting property, good peel strength and relatively low dielectric loss.

Description

Technical Field

[0001] The invention relates to the field of high-frequency and high-speed copper-clad laminate preparation, and in particular to a modified epoxy resin composition, a composite adhesive film, a copper-clad laminate and applications thereof. Background Art

[0002] At present, with the development of high-frequency communication, the requirements for the dielectric properties and thermal conductivity of copper-clad laminates are getting higher and higher. Conventional epoxy resin-based adhesive films and copper-clad laminates can no longer meet the requirements of the dielectric and thermal conductivity of materials in the communication field. It is very necessary to modify the epoxy resin or select a resin matrix with better dielectric properties. Among the composite materials for high-frequency and high-speed copper-clad laminates, polytetrafluoroethylene (PTFE) and polyphenylene ether (PPO) have very excellent dielectric properties, but the processing performance of the two is cross-cutting, and the adhesion to copper foil is relatively weak, which is easy to cause shedding or bubbling during the PCB processing process, thereby affecting the application of high-frequency circuit boards (PCBs). In addition, materials for high-frequency communications are also developing in the direction of miniaturization and integration. The substantial increase in the power density of the materials will generate a large amount of heat, and it is also urgent to improve the thermal conductivity of PCB materials.

[0003] It is a common practice to reduce the dielectric properties of epoxy resin while maintaining its excellent mechanical properties by modifying epoxy resin. CN 116080211B discloses a low dielectric loss PPO resin-based copper-clad laminate and its preparation method, wherein epoxy groups are grafted onto PPO after treatment with tetrabutylammonium bromide, and the PPO-based composite adhesive is obtained by blending with epoxy resin, silicon dioxide, etc., and then the PPO-based copper-clad laminate is obtained by impregnating and pulling glass fiber cloth, and copper foils are stacked and pressed on top and bottom. This scheme uses modified polyphenylene ether to improve the performance of epoxy resin and greatly improve the peel strength of the resin, but the PPO grafting modification changes the symmetrical structure of PPO itself, which enhances the polarity and causes a loss of its dielectric properties (dielectric loss is 0.01). At the same time, this scheme does not test the thermal conductivity of the material. Patent CN116285771A discloses thermal conductive fillers and preparation methods thereof, potting glue and preparation methods thereof, junction boxes, and photovoltaic modules. Boron nitride / mesoporous silica is used as fillers and added to epoxy resin to obtain high thermal conductivity materials, but its thermal conductivity is only 1.74W / (mK), and the dielectric properties of the material are not analyzed. In general, the dielectric properties and thermal conductivity of epoxy resin-based copper clad laminates still have the defect that they cannot be improved simultaneously, and further improvement and enhancement are necessary. Summary of the invention

[0004] In view of the above problems existing in the prior art, an object of the present invention is to provide a resin composition for improving the dielectric properties and thermal conductivity of a copper clad laminate by improving the structure of a resin substrate.

[0005] Another object of the present invention is to provide a composite adhesive film containing the resin composition.

[0006] Another object of the present invention is to provide a copper clad laminate containing the composite adhesive film.

[0007] Another object of the present invention is to provide application of the resin composition.

[0008] Another object of the present invention is to provide a method for preparing the resin composition.

[0009] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0010] In one aspect, the present invention provides a modified epoxy resin composition, which comprises, by weight, 5-8 parts of epoxy resin, 17-36 parts of modified polyphenylene ether, 22.5-55 parts of modified filler, 0.5-2 parts of curing agent, and 200-300 parts of solvent.

[0011] Preferably, the epoxy resin is bisphenol A epoxy resin or bisphenol epoxy resin.

[0012] Preferably, the modified polyphenylene ether is prepared by the following steps: dissolving 20 parts by weight of polyphenylene ether in 100 parts by weight of tetrahydrofuran, stirring evenly at 90° C., adding 10 parts by weight of 4,4-(hexafluoroisopropyl)diphenol, and after it is completely dissolved, adding 1 part by weight of benzoyl peroxide, stirring and reacting for 5 hours under a nitrogen protection atmosphere, cooling it to room temperature, adding excess methanol for washing, filtering, and drying at 100° C. for 12 hours to obtain the modified polyphenylene ether.

[0013] Preferably, the modified filler is prepared by the following steps:

[0014] Disperse 30 parts by weight of inorganic powder in 1000 parts by weight of ethanol, add 1 part by weight of silane coupling agent, and drip a 0.05 mol / L hydrochloric acid solution while stirring until the pH of the reaction system is 3-4, heat and stir in a water bath at 60°C for 2 hours, filter, and dry to obtain the modified filler.

[0015] Preferably, the inorganic powder is one or more of nano silicon dioxide, aluminum nitride, and boron nitride. Preferably, the particle size of nano silicon dioxide is 15-70 nm, the particle size of boron nitride is 3-30 μm, and the particle size of aluminum nitride is 2-20 μm.

[0016] Preferably, in the modified filler, the weight ratio of modified nano-silicon dioxide, modified aluminum nitride and modified boron nitride is (2.5-5): (16-35): (4-15).

[0017] Preferably, the silane coupling agent is one or more of γ-mercaptopropyltriethoxysilane (KH580), vinyltrimethoxysilane, methylvinyldiethoxysilane, vinyltri(β-methoxyethoxy)silane, γ-aminopropyltriethoxysilane (KH550), γ-glycidyloxypropyltrimethoxysilane (KH560), and γ-methacryloxypropyltrimethoxysilane (KH570).

[0018] Preferably, the solvent is an organic solvent, more preferably the solvent is one or more of tetrahydrofuran, toluene, xylene, N,N-dimethylformamide, particularly preferably toluene.

[0019] On the other hand, the present invention also provides a method for preparing the epoxy resin composition, which comprises the following steps: uniformly mixing epoxy resin, modified polyphenylene ether, modified filler, curing agent and solvent to obtain the epoxy resin composition.

[0020] On the other hand, the present invention also provides use of the modified epoxy resin composition according to the present invention in preparing a copper clad laminate.

[0021] On the other hand, the present invention further provides a composite adhesive film, which comprises the modified epoxy resin composition according to the present invention and a PTFE fiber cloth.

[0022] On the other hand, the present invention also provides a method for preparing the composite adhesive film, which comprises the following steps: performing plasma surface treatment on the PTFE fiber cloth, then immersing it in the resin composition, and obtaining the composite adhesive film by immersion pulling, drying, and hot pressing.

[0023] Preferably, the thickness of the PTFE fiber cloth is 20-100 μm, more preferably 50-100 μm.

[0024] Preferably, the gas used in the plasma surface treatment is one or more of H2, Ar, N2, O2 or CF4.

[0025] More preferably, the gas used in the plasma surface treatment is a mixed gas of H2, CF4 and O2 in a volume ratio of (1-3.5):1:1, with a gas flow rate of 30-80 mL / min, a power of 300-2000 W, and an absolute vacuum degree of ≤1×10 -6 Pa, the surface treatment temperature is 70-160°C, and the treatment time is 10-60min, more preferably 10-30min.

[0026] Most preferably, the gas used in the plasma surface treatment is a mixed gas of H2, CF4 and O2, with a volume ratio of 3:1:1, a gas flow rate of 50 mL / min, a power of 500 W, and an absolute vacuum of 0.5×10 -6 Pa, the surface treatment temperature is 120℃ and the treatment time is 25min.

[0027] On the other hand, the present invention also provides use of the composite adhesive film according to the present invention in preparing a copper clad laminate.

[0028] On the other hand, the present invention further provides a copper clad laminate comprising the composite adhesive film according to the present invention.

[0029] Preferably, the copper clad laminate is based on the modified epoxy resin composition of the present invention, and comprises a first copper foil layer, a first modified epoxy resin-based composite material layer, a PTFE fiber cloth layer, a second modified epoxy resin-based composite material layer, and a second copper foil layer arranged in sequence, and the first modified epoxy resin-based composite material layer and the second modified epoxy resin-based composite material layer are both made of the modified epoxy resin composition according to the present invention.

[0030] The present invention also provides a method for preparing the copper clad laminate, which comprises the following steps: after subjecting the composite adhesive film to plasma surface treatment, copper foils are stacked up and down for hot pressing treatment to obtain the copper clad laminate.

[0031] Preferably, the temperature range of hot pressing is 180-200°C.

[0032] Preferably, the pressure range of hot pressing is 8-10 MPa.

[0033] Preferably, the hot pressing time is 1.5-2 hours.

[0034] On the other hand, the present invention also provides the use of the copper clad laminate according to the present invention in the preparation of a high-frequency circuit board.

[0035] In the composition of the present invention, the modified polyphenylene ether has good compatibility with the epoxy resin, and the surface modification of the filler is used to greatly improve the interface compatibility of the filler and the modified epoxy resin composition system, thereby improving the uniformity of the filler in the matrix, and constructing a three-dimensional network structure in the resin matrix through the compounding of the filler to form an efficient heat conduction path with excellent dielectric properties. The copper-clad laminate based on the modified epoxy resin composition provided by the present invention has uniform thickness, maintains ultra-low dielectric constant and dielectric loss, and achieves high peel strength and high thermal conductivity of the copper-clad laminate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic structural diagram of a modified epoxy resin-based copper clad laminate according to the present invention.

[0037] Figure numerals: 1 - copper foil layer, 2 - modified epoxy resin-based composite material layer, 3 - PTFE fiber cloth layer. DETAILED DESCRIPTION

[0038] In order to better understand the technical solution of the present invention, the present invention is further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention, rather than to limit the scope of the present invention.

[0039] The following polyphenylene ether powder (S201, Mn = 12600 g / mol) was purchased from Asahi Kasei Industries, Japan; epoxy resin was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; tetrahydrofuran, toluene, chlorobenzene, methanol, bisphenol F, 4,4-(hexafluoroisopropylidene) diphenol, benzoyl peroxide, silane coupling agent, ethanol and other reagents were purchased from Shanghai Aladdin Chemical Reagent Co., Ltd.;

[0040] Other reagents and experimental instruments are commercially available in the art.

[0041] Example 1

[0042] 1. Preparation of modified epoxy resin composition

[0043] (1) Preparation of modified polyphenylene ether

[0044] 20 g of polyphenylene ether was dissolved in 100 g of tetrahydrofuran, stirred at 90° C., 10 g of 4,4-(hexafluoroisopropylidene)diphenol was added, and after it was completely dissolved, 1.0 g of benzoyl peroxide was added, and the mixture was stirred and reacted for 5 hours under a nitrogen atmosphere. After it was cooled to room temperature, excess methanol was added for washing, filtered, and dried at 100° C. for 12 hours to obtain the modified polyphenylene ether.

[0045] (2) Surface modification of inorganic powders

[0046] Mix 30g of nano-silica (particle size of 15-70nm, for example, 15nm) with 1000g of ethanol, add 1.0g of methylvinyldimethoxysilane, and drip a 0.05mol / L hydrochloric acid solution while stirring until the pH of the reaction system reaches 3.5. Heat and stir in a water bath at 60°C for 2 hours, filter to remove the solvent, and dry at 100°C to obtain modified nano-silica.

[0047] Take 30g of aluminum nitride (particle size is 3-30μm, for example, 20μm) and mix it with 1000g of ethanol, add 0.6g of γ-aminopropyltriethoxysilane, and dropwise add a 0.05mol / L hydrochloric acid solution while stirring until the pH of the reaction system is 4. Heat and stir in a water bath at 60℃ for 2 hours, filter to remove the solvent, and dry at 100℃ to obtain modified aluminum nitride.

[0048] Take 30g of boron nitride (particle size is 2-20μm, for example, 3μm) and mix it with 1000g of ethanol, add 0.6g of γ-aminopropyltriethoxysilane, and dropwise add a 0.05mol / L hydrochloric acid solution while stirring until the pH of the reaction system is 3. Heat and stir in a water bath at 60℃ for 2 hours, filter to remove the solvent, and dry at 100℃ to obtain modified boron nitride.

[0049] (3) Preparation of composite glue

[0050] Mix 36 g of the modified polyphenylene ether obtained in the above step (1), 8 g of epoxy resin E44, 2 g of diaminodiphenylmethane (DDM) and 250 g of toluene, add 5 g of the modified nano-silicon dioxide obtained in the above step (2), 35 g of the modified aluminum nitride obtained in the above step (2), and 15 g of the modified boron nitride obtained in the above step (2), stir for 3 hours, mix well, and obtain a modified epoxy resin composition.

[0051] 2. Preparation of composite film

[0052] The PTFE fiber cloth (thickness of 20-100 μm, for example, 50 μm) is subjected to plasma surface treatment and then immersed in the above-mentioned low dielectric composite resin composition. After immersion pulling, drying and hot pressing, a low dielectric composite adhesive film is obtained.

[0053] The gas used in the plasma surface treatment is a mixture of H2, CF4 and O2 with a volume ratio of 3:1:1, a gas flow rate of 50 mL / min, a power of 300 W, and an absolute vacuum of 0.5×10 -6 Pa, the temperature is 120℃ and the treatment time is 25min.

[0054] 3. Preparation of modified epoxy resin based copper clad laminate

[0055] The composite adhesive film is sequentially subjected to plasma surface treatment, and a layer of copper foil (thickness of about 35 μm) is stacked on the upper and lower sides of the adhesive film, and then vacuum hot-pressed to obtain a modified epoxy resin-based copper-clad laminate.

[0056] The gas used in the plasma surface treatment is a mixture of H2, CF4 and O2 with a volume ratio of 3:1:1, a gas flow rate of 50 mL / min, a power of 300 W, and an absolute vacuum of 0.5×10 -6 Pa, the temperature is 120℃ and the treatment time is 25min.

[0057] The process conditions of vacuum hot pressing are as follows: hot pressing temperature is 200°C, pressure is 10MPa, and time is 1.5 hours.

[0058] The obtained multilayer structure of low dielectric modified epoxy resin based copper clad laminate is as follows Figure 1The copper clad laminate has a multi-layer composite structure, which includes a copper foil layer 1, a modified epoxy resin-based composite material layer 2, a PTFE fiber cloth layer 3, a modified epoxy resin-based composite material layer 2, and a copper foil layer 1 in sequence.

[0059] Example 2

[0060] 1. Preparation of modified epoxy resin composition

[0061] (1) Preparation of modified polyphenylene ether

[0062] Same as Example 1.

[0063] (2) Surface modification of inorganic fillers

[0064] Same as Example 1.

[0065] (3) Preparation of composite glue

[0066] Mix 22 g of the modified polyphenylene ether obtained in the above step (1), 5 g of epoxy resin E44, 0.5 g of DDM and 200 g of toluene, add 2.5 g of the modified nano-silicon dioxide obtained in the above step (2), 16 g of the modified aluminum nitride obtained in the above step (2), and 4 g of the modified boron nitride obtained in the above step (2), stir for 3 hours, mix well, and obtain a modified epoxy resin composition.

[0067] 2. Preparation of composite film

[0068] The thickness of PTFE is 80 μm. Other processing step conditions and parameters are the same as those in Example 1.

[0069] 3. Preparation of modified epoxy resin based copper clad laminate

[0070] The process conditions of vacuum hot pressing are as follows: hot pressing temperature is 180° C., pressure is 8 MPa, and time is 1.5 hours. In addition, other processing step condition parameters are the same as those in Example 1.

[0071] Example 3

[0072] 1. Preparation of modified epoxy resin composition

[0073] (1) Preparation of modified polyphenylene ether

[0074] Same as Example 1.

[0075] (2) Surface modification of inorganic fillers

[0076] Same as Example 1.

[0077] (3) Preparation of composite glue

[0078] Mix 17 g of the modified polyphenylene ether obtained in the above step (1), 5 g of epoxy resin E44, 0.5 g of DDM and 300 g of toluene, add 2.5 g of the modified nano-silicon dioxide obtained in the above step (2), 17.5 g of the modified aluminum nitride obtained in the above step (2), and 7.5 g of the modified boron nitride obtained in the above step (2), stir for 3 hours, mix well, and obtain a modified epoxy resin composition.

[0079] 2. Preparation of composite film

[0080] The thickness of PTFE is 100 μm. Other processing step conditions and parameters are the same as those in Example 1.

[0081] 3. Preparation of modified epoxy resin based copper clad laminate

[0082] The process conditions of vacuum hot pressing are as follows: hot pressing temperature is 190° C., pressure is 8 MPa, and time is 2 hours. In addition, other processing step condition parameters are the same as those in Example 1.

[0083] Comparative Example 1

[0084] The only difference from Example 1 is that the modified polyphenylene ether is omitted, the added amount of epoxy resin is 40 g, and the DDM is 5 g. Other raw materials and preparation steps are the same.

[0085] Comparative Example 2

[0086] The only difference from Example 1 is that an equal amount of conventional unmodified polyphenylene ether is used to replace the modified polyphenylene ether, and other raw materials and preparation steps are the same.

[0087] Comparative Example 3

[0088] The only difference from Example 1 is that the PTFE fiber cloth is omitted, and other raw materials and preparation steps are the same.

[0089] Comparative Example 4

[0090] The only difference from Example 1 is that the PTFE fiber cloth is not subjected to plasma treatment during the preparation of the composite film, and other raw materials and preparation steps are the same.

[0091] Comparative Example 5

[0092] The only difference from Example 1 is that an equal amount of conventional unmodified inorganic filler is used to replace the modified inorganic filler, that is, the step of modifying the inorganic filler is omitted, and other raw materials and preparation steps are the same.

[0093] Comparative Example 6

[0094] The only difference from Example 1 is that the modified silicon dioxide is omitted, and other raw materials and preparation steps are the same.

[0095] Comparative Example 7

[0096] The only difference from Example 1 is that the modified aluminum nitride is omitted, and other raw materials and preparation steps are the same.

[0097] Comparative Example 8

[0098] The only difference from Example 1 is that the modified boron nitride is omitted, and other raw materials and preparation steps are the same.

[0099] According to the IEC 61189-2-721 (2015-04) standard, at a frequency of 10 GHz, the dielectric constant and dielectric loss test of the polyphenylene ether based copper clad laminate samples obtained in Examples 1-3 and Comparative Examples 1-8 were tested; according to the IPC-TM-650 2.4.8 standard, the peel strength of the above polyphenylene ether based copper clad laminate samples was tested, and the results are shown in Table 1 below.

[0100] Table 1

[0101]

[0102] As shown in Table 1, compared with Examples 1-3 of the present invention, Comparative Example 1 contains only epoxy resin without adding modified polyphenylene ether, and its dielectric constant and loss are larger.

[0103] In Comparative Example 2, unmodified polyphenylene ether is added, which has poor compatibility with epoxy resin, which will increase the interfacial thermal resistance between the resins and reduce the thermal conductivity of the material.

[0104] Comparative Example 3 does not add PTFE fiber cloth, has no supporting carrier, and cannot use PTFE with better dielectric properties to reduce the dielectric properties of the film, so the peel strength is low.

[0105] In Comparative Example 4, PTFE is not plasma modified, and the compatibility between the resin matrix and the fiber cloth is greatly reduced, resulting in a large dielectric loss, reduced thermal conductivity, and low peel strength.

[0106] In Comparative Example 5, the inorganic filler was not modified, resulting in decreased compatibility between the filler and the resin matrix, increased interfacial thermal resistance, reduced thermal conductivity of the material, and low peel strength.

[0107] In Comparative Example 6, nano-silicon dioxide is not added, and the dielectric properties of the film are not substantially improved, resulting in relatively high dielectric properties. At the same time, it also affects the formation of thermal conductive paths in the material, resulting in relatively low thermal conductivity.

[0108] In Comparative Example 7, no modified aluminum nitride is added, which will result in a discontinuous heat conduction path formed by the filler in the composite material, resulting in a decrease in thermal conductivity.

[0109] In Comparative Example 8, no modified boron nitride is added. Boron nitride has high thermal conductivity and low dielectric loss. The lack of small-sized boron nitride will also lead to discontinuous thermal conduction paths and increase dielectric loss.

[0110] It can be seen that the modified epoxy resin-based copper clad laminate provided by the present invention has excellent thermal conductivity and good peel strength, as well as low dielectric loss, and can be widely used in high-frequency circuit boards.

[0111] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0112] It should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0113] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A modified epoxy resin composition, characterized in that By weight, it comprises 5-8 parts of epoxy resin, 17-36 parts of modified polyphenylene ether, 22.5-55 parts of modified filler, 0.5-2 parts of curing agent and 200-300 parts of solvent.

2. The modified epoxy resin composition according to claim 1, characterized in that The epoxy resin is bisphenol A epoxy resin or bisphenol epoxy resin.

3. The modified epoxy resin composition according to claim 1, characterized in that The modified polyphenylene ether is prepared by the following steps: dissolving 20 parts by weight of polyphenylene ether in 100 parts by weight of tetrahydrofuran, stirring evenly at 90° C., adding 10 parts by weight of 4,4-(hexafluoroisopropylidene)diphenol, and after it is completely dissolved, adding 1 part by weight of benzoyl peroxide, stirring and reacting for 5 hours under a nitrogen protection atmosphere, cooling it to room temperature, adding excess methanol for washing, filtering, and drying at 100° C. for 12 hours to obtain the modified polyphenylene ether.

4. The modified epoxy resin composition according to claim 1, characterized in that The modified filler is prepared by the following steps: Disperse 30 parts by weight of inorganic powder in 1000 parts by weight of ethanol, add 1 part by weight of silane coupling agent, and drip a 0.05 mol / L hydrochloric acid solution while stirring until the pH of the reaction system is 3-4, heat and stir in a water bath at 60°C for 2 hours, filter, and dry to obtain the modified filler.

5. The modified epoxy resin composition according to claim 4, characterized in that The inorganic powder is one or more of nano silicon dioxide, aluminum nitride and boron nitride.

6. The modified epoxy resin composition according to claim 4, characterized in that The silane coupling agent is one or more of γ-mercaptopropyltriethoxysilane, vinyltrimethoxysilane, methylvinyldiethoxysilane, vinyltri(β-methoxyethoxy)silane, γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

7. The modified epoxy resin composition according to claim 1, characterized in that The solvent is one or more of tetrahydrofuran, toluene, xylene, and N,N-dimethylformamide.

8. A composite adhesive film comprising the modified epoxy resin composition according to any one of claims 1 to 7 and a PTFE fiber cloth.

9. A copper clad laminate comprising the composite adhesive film according to claim 8.

10. Use of the modified epoxy resin composition according to any one of claims 1 to 7 in the preparation of copper-clad laminates, use of the composite adhesive film according to claim 8 in the preparation of copper-clad laminates, and use of the copper-clad laminate according to claim 9 in the preparation of high-frequency circuit boards.

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