CN111303788A - High frequency composite material and preparation method thereof - Google Patents

Abstract

The invention relates to the field of electronic materials, and discloses a high-frequency composite material and a preparation method thereof. The high-frequency composite material comprises at least two layers of low-k polymer porous membranes and an impregnated adhesive layer, which are formed in each layer. The inner and outer sides of a layer of low-k polymer porous membrane; wherein, the impregnated adhesive layer includes the following components in terms of mass fraction: 100 parts of epoxy resin, 5-130 parts of curing agent, 0.5-25 parts of foaming agent, thermal conductivity 1 to 15 parts of a flame retardant, 5 to 20 parts of a flame retardant, and 0.5 to 5 parts of a coupling agent. The invention can reduce the dielectric constant and dielectric loss of the high-frequency composite material through the low-k polymer porous film and the impregnated adhesive layer, and can improve the mechanical strength, compressive strength, tensile strength and heat resistance of the high-frequency composite material. , corrosion resistance, thermal conductivity and flame retardant properties.

Description

High frequency composite material and preparation method thereof

technical field

The invention relates to the field of electronic materials, in particular to a high-frequency composite material and a preparation method thereof.

Background technique

High-frequency substrates are the basic materials for the development of the high-frequency communication industry. In the 5G era, traditional substrates will cause greater signal transmission loss and cause "distortion". In the high frequency system, the signal loss mainly comes from the loss of the filling medium and the copper skin, in which the medium plays a decisive role. The dielectric constant is relatively high, the tangent loss angle is large, and the stability at high frequencies is poor, so there will be large losses when transmitting high-frequency signals. Therefore, the improvement of the dielectric properties of the substrate becomes particularly important. and urgency.

Epoxy resin matrix is an important base material for the preparation of high-frequency mobile phone materials. Main technical characteristics and applications: stable electrical insulation performance, good flatness, smooth surface, no pits, and thickness tolerance standards, suitable for high-performance electronic insulation requirements. product. The improvement of the dielectric properties of epoxy resin matrix is the key to obtain high-performance high-frequency mobile phone materials.

At present, the main means for improving the dielectric properties of epoxy resin matrix include (1) using styrene-maleic anhydride copolymer. For example, the patent application with the application number CN201310753184 discloses styrene-maleic anhydride copolymer as epoxy The curing agent for resin, in which the styrene structure has excellent dielectric properties, can be introduced into the cured cross-linked structure to achieve low dielectric constant and dielectric loss factor. (2) Use a glycidyl ether containing a low-polarity styrene structure, for example, the patent application with the application number CN200910189730 discloses that the glycidyl ether containing a low-polarity styrene structure has better thermal stability and heat resistance , The prepreg made has the characteristics of low dielectric constant and low dielectric loss factor. (3) Active ester is used as curing agent. Active ester is a compound obtained after the carboxylic acid group is blocked by alcohol. The cured product has low polarity and good dielectric properties. For example, the patent application with the application number of CN201310247061 discloses an active ester containing a dicyclopentadiene structure, and the dicyclopentadiene is an alicyclic structure, which can further reduce the dielectric loss. For example, the patent application with the application number CN201410232763 discloses a phosphorus-containing active ester curing agent, which can maintain the composition with a low moisture absorption rate, good heat and humidity resistance and excellent flame retardancy under the premise of improving the flame retardancy of the resin composition dielectric properties. (4) Modification with polyphenylene ether resin. For example, in the patent application with the application number of CN201010581146, modification with polyphenylene ether resin can be used to obtain epoxy resin substrates for copper clad laminates with excellent dielectric properties.

However, the effect of the above improvements is not good, and the obtained high-frequency composite materials have high dielectric constant and dielectric loss, which can only meet the needs of low-end products. There is still a big gap in the need for low dielectric loss.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies in the prior art, and to provide a high-frequency composite material with low dielectric constant, low dielectric loss, high mechanical strength, high flame retardancy and high thermal conductivity and a preparation method thereof .

The purpose of this invention is to realize through the following technical solutions:

A high-frequency composite material, comprising at least two layers of a low-k polymer porous membrane arranged in layers and an impregnating glue layer that penetrates into the low-k polymer porous membrane by dipping and is attached to the outside of the low-k polymer porous membrane ;

Wherein, the impregnated adhesive layer includes the following components in terms of mass fraction: 100 parts of epoxy resin, 5-130 parts of curing agent, 0.5-25 parts of foaming agent, 1-15 parts of thermal conductive agent, and 5-15 parts of flame retardant. 20 parts, and 0.5-5 parts of coupling agent.

In one embodiment, the material of the low-k polymer porous membrane includes at least one of PTFE, PSF, PPO, PPS, PEEK, PEK, PEKK, PEKEKK, PEEKK, PI and MPI.

In one embodiment, the epoxy equivalent of the epoxy resin is 0.15-0.50.

In one embodiment, the curing agent is a high-temperature curing agent with a curing temperature greater than 100°C.

In one embodiment, the blowing agent includes azodicarbonamide, azobisisobutyronitrile, N,N'-dinitrosopentamethylenetetramine, 4,4'-oxobis At least one of benzenesulfonyl hydrazide and p-toluenesulfonyl hydrazide.

In one of the embodiments, the thermally conductive agent comprises a dispersion of nanoboron nitride that is highly dissociated and dispersed in the liquid component.

In one embodiment, the flame retardant includes dimethyl methyl phosphate; or the coupling agent includes a silane coupling agent.

A preparation method of a high-frequency composite material, comprising the following steps:

Mixing epoxy resin, curing agent, foaming agent, flame retardant, coupling agent and thermal conductive agent, stirring evenly, to obtain a premix; heat treatment of the premix to obtain an epoxy resin adhesive; wherein, the The mass ratio of the epoxy resin, the curing agent, the foaming agent, the thermally conductive agent, the flame retardant and the coupling agent is 100: (5-130): (0.5-25): (1～15): (5～20): (0.5～5);

Impregnating at least two layers of low-k polymer porous membranes stacked in layers in the epoxy resin adhesive to perform a lamination operation, so as to form an impregnating adhesive layer on the inside and outside of each layer of the low-k polymer porous membrane, to obtain Preparing a composite membrane; curing the preparatory composite membrane to obtain a high-frequency composite material.

In one embodiment, the temperature of the heat treatment is 100°C to 150°C, and the time of the heat treatment is 2.0h to 6.0h; or the temperature of the curing treatment is 200°C to 250°C, and the temperature of the curing treatment The time is 1h to 24h.

In one embodiment, before the operation of mixing the epoxy resin, the curing agent, the foaming agent, the flame retardant, the coupling agent and the thermally conductive agent, nanometer The boron nitride powder is added to the liquid component to obtain a boron nitride mixed solution; then ultrasonic dispersion operation is performed on the boron nitride mixed solution, so that the nano boron nitride powder is uniformly dispersed in the liquid component , to obtain the thermally conductive agent.

Compared with the prior art, the present invention has at least the following advantages:

The invention uses the low-k polymer porous film as the reinforcing material to improve the mechanical strength, compressive strength and tensile strength of the high-frequency composite material, and reduce the dielectric constant and dielectric loss of the high-frequency composite material; It is used as an adhesive to increase the adhesion between two adjacent layers of low-k polymer porous membranes. The impregnated adhesive layer used is mainly made of epoxy resin with low dielectric constant, and is added with a suitable ratio of curing agent, Foaming agent, thermal conductive agent, flame retardant and coupling agent are used to improve the heat resistance, corrosion resistance, thermal conductivity and flame retardant performance of the impregnated adhesive layer; and then through the porous structure of the low-k polymer porous film, to further Reduce its own dielectric constant and dielectric loss, and increase its adhesion to the dip layer. In this way, the present invention can reduce the dielectric constant and dielectric loss of the high-frequency composite material through the low-k polymer porous film and the impregnated adhesive layer, and can improve the mechanical strength, compressive strength, tensile strength, resistance of the high-frequency composite material. Thermal properties, corrosion resistance, thermal conductivity and flame retardant properties.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation of the scope, and for those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a flow chart of the steps of a method for preparing a high-frequency composite material according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a high-frequency composite material according to an embodiment of the present invention.

Detailed ways

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the related drawings. The preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the present disclosure is provided.

It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for the purpose of illustration only and do not represent the only embodiment.

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 belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In one embodiment, please refer to FIG. 2 , a high-frequency composite material 10 includes at least two layers of low-k polymer porous membranes 110 stacked in layers and infiltrated into the low-k polymer porous membrane 110 by dipping and attached to the low-k polymer porous membrane 110 . The impregnated adhesive layer 120 on the outer side of the low-k polymer porous membrane 110; wherein, the impregnated adhesive layer 120 includes the following components in terms of mass fraction: 100 parts of epoxy resin, 5-130 parts of curing agent, and 0.5 parts of foaming agent ~25 parts, 1-15 parts of thermal conductive agent, 5-20 parts of flame retardant, and 0.5-5 parts of coupling agent.

It should be noted that the low-k polymer porous film 110 refers to a polymer porous film with low dielectric constant and low dielectric loss. The present invention uses the low-k polymer porous film 110 as a reinforcing material to improve the high-frequency composite material 10 The mechanical strength, compressive strength and tensile strength of the high-frequency composite material 10 are reduced, and the dielectric constant and dielectric loss of the high-frequency composite material 10 are reduced; the impregnated adhesive layer 120 is used as a binder to increase the adjacent two layers of low-k polymer porous membranes The adhesive force between 110 and 110, the impregnated adhesive layer 120 used is epoxy resin with low dielectric constant as the main raw material, adding appropriate proportions of curing agent, foaming agent, thermal conductivity agent, flame retardant and coupling agent, to improve the heat resistance, corrosion resistance, thermal conductivity and flame retardant performance of the impregnating adhesive layer 120; and then through the porous structure of the low-k polymer porous film 110 to further reduce its own dielectric constant and dielectric loss, and Increase its adhesion with the impregnating glue layer 120 . In this way, the present invention can reduce the dielectric constant and dielectric loss of the high-frequency composite material 10 through the low-k polymer porous membrane 110 and the impregnated adhesive layer 120 , and can improve the mechanical strength, compressive strength and tensile strength of the high-frequency composite material 10 . Tensile strength, heat resistance, corrosion resistance, thermal conductivity and flame retardant properties.

In order to further reduce the dielectric constant and dielectric loss of the high-frequency composite material 10, improve the mechanical strength, compressive strength, tensile strength, electrical insulation properties, chemical corrosion resistance, heat resistance and operating temperature of the high-frequency composite film 10 In one embodiment, the low-k polymer porous membrane 110 is a woven fiber membrane or a hollow fiber membrane. In this way, the dielectric constant and dielectric loss of the high-frequency composite material 10 can be further reduced. In order to further reduce the dielectric constant and dielectric loss of the high-frequency composite material 10 and improve the mechanical strength, compressive strength and tensile strength of the high-frequency composite material 10, in one embodiment, the material of the low-k polymer porous membrane 110 Including at least one of PTFE, PSF, PPO, PPS, PEEK, PEK, PEKK, PEKEKK, PEEKK, PI and MPI. For example, the material of the low-k polymer porous membrane 110 includes PTFE, PSF, PPO, PPS, PEEK, PEK, PEKK, PEKEKK, PEEKK, PI or MPI. In this way, PTFE (polytetrafluoroethylene), PSF (polysulfone), PPO (poly2,6-dimethyl-1,4-phenylene ether), PPS (polyphenylene sulfide), PEEK (polyether) are selected. ether ketone), PEK (polyether ketone), PEKK (polyether ketone ketone), PEKEKK (polyether ketone ether ketone ketone), PEEKK (polyether ether ketone ketone), PI (polyimide) and MPI (polyacyl Imine resin) and other polymer insulating film materials, they contain low dielectric groups, such as aromatic polymers, fluorine-containing groups, silicon-containing groups, etc., so that they have low dielectric constant and low dielectric loss, It also has excellent mechanical strength, compressive strength, tensile strength, electrical insulation properties, chemical corrosion resistance, heat resistance, wide operating temperature range, low water absorption, and small changes in dielectric properties in the high frequency range, which can be further reduced. The dielectric constant and dielectric loss of the high-frequency composite film 10 improve the mechanical strength, compressive strength, tensile strength, electrical insulation performance, chemical resistance, heat resistance and operating temperature range of the high-frequency composite film 10 .

In order to further improve the mechanical strength, compressive strength, tensile strength, heat resistance, corrosion resistance, thermal conductivity and heat dissipation performance of the impregnating adhesive layer 120, in one embodiment, the thermally conductive agent includes a highly dissociated liquid component. Dispersed nano-boron nitride dispersion. For example, the concentration of the nano-boron nitride dispersion liquid containing the nano-boron nitride is preferably 1 mg/mL to 100 mg/mL. For example, the nano-boron nitride dispersion liquid contains nano-boron nitride at a concentration of 1 mg/mL, 5 mg/mL, 10 mg/mL, 15 mg/mL, 20 mg/mL, 25 mg/mL, 30 mg/mL, 35 mg/mL, 40mg/mL, 45mg/mL, 50mg/mL, 55mg/mL, 60mg/mL, 65mg/mL, 70mg/mL, 75mg/mL, 80mg/mL, 85mg/mL, 90mg/mL, 95mg/mL or 100mg/mL mL. For example, the concentration of the nano boron nitride dispersion liquid containing the nano boron nitride is more preferably 5 mg/mL to 20 mg/mL. For example, the liquid component contained in the nano-boron nitride dispersion liquid is an aqueous sodium chloride solution with a concentration of 0.1 wt % to 5.0 wt %. For example, the concentration of the sodium chloride aqueous solution is 0.1wt%, 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, 2.5wt%, 3.0wt%, 3.5wt%, 4.0wt%, 4.5wt% or 5.0wt%. For example, the concentration of the sodium chloride aqueous solution is preferably 0.5 wt % to 2.5 wt %. It should be noted that boron nitride itself has good mechanical strength, electrical insulation, thermal conductivity, chemical resistance, high temperature resistance, radiation resistance, oxidation resistance and other properties. Nano-scale boron nitride is selected. The smaller the particle, the better the reinforcement effect on epoxy resin. It is highly dissociated and dispersed in the liquid component, and then mixed with epoxy resin to solve the problem of the viscosity of nano-scale boron nitride. The high epoxy resin is difficult to mix evenly, so that the nano-scale boron nitride can be well dispersed in the epoxy resin system, so that the mechanical strength, compressive strength and tensile strength of the impregnating adhesive layer 120 can be further improved. Strength, electrical insulation, heat resistance, corrosion resistance, oxidation resistance, thermal conductivity and heat dissipation.

In order to obtain a more suitable viscosity for the dipping adhesive layer 120, in one embodiment, the epoxy equivalent of the epoxy resin is preferably 0.15-0.50. For example, the epoxy resin has an epoxy equivalent weight of 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45 or 0.50. In this way, the dipping glue layer 120 can obtain a more suitable viscosity. For example, the epoxy equivalent of the epoxy resin is more preferably 0.20 to 0.30. In this way, the dipping glue layer 120 can obtain a more suitable viscosity.

In order to further improve the mechanical strength, heat resistance and wear resistance of the impregnating adhesive layer 120, in one embodiment, the curing agent is preferably a high-temperature curing agent with a curing temperature greater than 100°C. For example, the curing agent includes m-phenylenediamine, dicyandiamide, sebacic acid dihydrazide, maleic anhydride, phthalic anhydride, dodecenylsuccinic anhydride, hexahydrophthalic anhydride, " At least one of 70" acid anhydride, Nadic acid anhydride, polyazelaic acid anhydride and 3,3',4,4'-benzophenone tetraacid dianhydride. For example, the curing agent includes m-phenylenediamine and sebacic acid dihydrazide. For example, the curing agent is preferably a high-temperature curing agent with a curing temperature of 150°C to 250°C. For example, the curing agents include sebacic acid dihydrazide, maleic anhydride, phthalic anhydride, dodecenylsuccinic anhydride, hexahydrophthalic anhydride, "70" anhydride, nadic anhydride, polyamide At least one of azelaic anhydride and 3,3',4,4'-benzophenone tetraacid dianhydride. For example, the curing agents include sebacic acid dihydrazide, maleic anhydride, phthalic anhydride, dodecenylsuccinic anhydride, hexahydrophthalic anhydride, "70" anhydride, nadic anhydride, polyamide Azelaic anhydride or 3,3',4,4'-benzophenone tetracarboxylic dianhydride. For example, the curing agent includes maleic anhydride and phthalic anhydride. In this way, the mechanical strength, heat resistance and wear resistance of the impregnating glue layer 120 can be further improved.

In order to further improve the compressive strength and tensile strength of the impregnating adhesive layer 120, in one embodiment, the foaming agent includes azodicarbonamide, azobisisobutyronitrile, N,N'-dinitroso five times At least one of methyltetramine, 4,4'-oxobisbenzenesulfonylhydrazide and p-toluenesulfonylhydrazide. For example, the blowing agent includes azodicarbonamide, azobisisobutyronitrile, N,N'-dinitrosopentamethylenetetramine, 4,4'-oxobisbenzenesulfonylhydrazide or p-toluenesulfonylhydrazide. For example, the blowing agents include azodicarbonamide and azobisisobutyronitrile. In this way, the compressive strength and tensile strength of the impregnating adhesive layer 120 can be further improved.

In order to further improve the flame retardant performance of the impregnating glue layer 120, in one embodiment, the flame retardant includes dimethyl methyl phosphate. In this way, the flame retardant performance of the impregnating glue layer 120 can be further improved.

In order to further improve the mechanical strength, electrical properties and weather resistance of the impregnating adhesive layer 120, in one embodiment, the coupling agent includes a silane coupling agent. For example, the coupling agent includes at least one of KH550 coupling agent, KH560 coupling agent, KH570 coupling agent, KH792 coupling agent and DL602 coupling agent. For example, the coupling agent includes KH550 coupling agent, KH560 coupling agent, KH570 coupling agent, KH792 coupling agent or DL602 coupling agent. For example, the coupling agent includes KH550 coupling agent and KH560 coupling agent. In this way, through the silane coupling agent, a "molecular bridge" is set up between the interface of the epoxy resin and the inorganic material such as the thermal conductive agent, which can improve the dispersibility and adhesion of the inorganic material such as the thermal conductive agent in the epoxy resin, and can improve the inorganic material. The compatibility with the epoxy resin further improves the mechanical strength, electrical properties and weather resistance of the impregnating adhesive layer 120 .

In another embodiment, the impregnating adhesive layer 120 includes the following components in terms of mass fraction: 100 parts of epoxy resin, 30-80 parts of curing agent, 5-20 parts of foaming agent, 3-13 parts of thermal conductive agent, 8 to 16 parts of the burning agent, and 2 to 4 parts of the coupling agent. In this way, the heat resistance, corrosion resistance, thermal conductivity and flame retardancy of the impregnating glue layer 120 can be further improved.

Please refer to FIG. 1 and FIG. 2 , a preparation method of a high-frequency composite material 10 includes the following steps:

S110, adding nano boron nitride powder to the liquid component to obtain a boron nitride mixed solution; then performing an ultrasonic dispersion operation on the boron nitride mixed solution, so that the nano boron nitride powder is in the liquid component Disperse evenly in the fraction to obtain a thermally conductive agent.

In this way, nano-scale boron nitride is selected, and the smaller the particles, the better the reinforcement effect on epoxy resin, and then by highly dissociating and dispersing in the liquid component, and then mixing with epoxy resin, to solve the problem of nano-scale boron nitride. It is difficult to mix evenly in epoxy resin with high viscosity, so that nano-scale boron nitride can be well dispersed in the epoxy resin system, so as to further improve the mechanical strength, compressive strength and resistance of the impregnating adhesive layer 120 Tensile strength, electrical insulation, heat resistance, corrosion resistance, oxidation resistance, thermal conductivity and heat dissipation.

In order to further improve the mechanical strength, compressive strength, tensile strength, electrical insulation, heat resistance, corrosion resistance, oxidation resistance, thermal conductivity and heat dissipation of the impregnating glue layer 120, for example, the nano-boron nitride dispersion The concentration of the liquid containing nano-boron nitride is preferably 1 mg/mL to 100 mg/mL. For example, the concentration of the nano boron nitride dispersion liquid containing the nano boron nitride is more preferably 5 mg/mL to 20 mg/mL. For example, the liquid component contained in the nano-boron nitride dispersion liquid is an aqueous sodium chloride solution with a concentration of 0.1 wt % to 5.0 wt %. For example, the concentration of the sodium chloride aqueous solution is preferably 0.5 wt % to 2.5 wt %. In this way, the mechanical strength, compressive strength, tensile strength, electrical insulation, heat resistance, corrosion resistance, oxidation resistance, thermal conductivity and heat dissipation of the impregnating glue layer 120 can be further improved.

In order to further improve the dispersion effect of the ultrasonic dispersion operation, for example, the ultrasonic dispersion operation is specifically performed in a water bath for 1.0 h to 3.0 h under airtight conditions. For example, the ultrasonic dispersion operation is specifically performed in a water bath for 1.0h, 1.5h, 2.0h, 2.5h or 3.0h under airtight conditions. In this way, the dispersion effect of the ultrasonic dispersion operation can be further improved, and a highly dissociated and uniformly dispersed nano-boron nitride dispersion can be obtained.

S120, mixing epoxy resin, curing agent, foaming agent, flame retardant, coupling agent and the thermally conductive agent, stirring evenly, to obtain a premix; heat treatment of the premix to obtain an epoxy resin adhesive ; Wherein, the mass ratio of the epoxy resin, the curing agent, the foaming agent, the thermally conductive agent, the flame retardant and the coupling agent is 100:(5～130):(0.5 to 25): (1 to 15): (5 to 20): (0.5 to 5).

In this way, epoxy resin adhesives use epoxy resin with low dielectric constant as the main raw material, and add appropriate proportions of curing agent, foaming agent, thermal conductive agent, flame retardant and coupling agent to improve the resistance of epoxy resin adhesives. Thermal properties, corrosion resistance, thermal conductivity and flame retardant properties; and then through heat treatment to eliminate the stress of epoxy resin adhesives, improve the performance of epoxy resin adhesives.

In one embodiment, the epoxy equivalent of the epoxy resin is preferably 0.15-0.50. For example, the epoxy equivalent of the epoxy resin is more preferably 0.20 to 0.30. In this way, a more suitable viscosity can be obtained for the epoxy resin adhesive. In one embodiment, the curing agent is preferably a high-temperature curing agent with a curing temperature greater than 100°C. For example, the curing agent is preferably a high-temperature curing agent with a curing temperature of 150°C to 250°C. For example, the curing agents include sebacic acid dihydrazide, maleic anhydride, phthalic anhydride, dodecenylsuccinic anhydride, hexahydrophthalic anhydride, "70" anhydride, nadic anhydride, polyamide At least one of azelaic anhydride and 3,3',4,4'-benzophenone tetraacid dianhydride. In this way, the mechanical strength, heat resistance and wear resistance of the epoxy resin adhesive can be further improved. In one embodiment, the foaming agent includes azodicarbonamide, azobisisobutyronitrile, N,N'-dinitrosopentamethylenetetramine, 4,4'-oxobisbenzenesulfonyl At least one of hydrazine and p-toluenesulfonyl hydrazide. In this way, the compressive strength and tensile strength of the epoxy resin adhesive can be further improved. In one embodiment, the flame retardant includes dimethyl methyl phosphate. In this way, the flame retardant performance of the epoxy resin adhesive can be further improved. In one embodiment, the coupling agent includes a silane coupling agent. For example, the coupling agent includes at least one of KH550 coupling agent, KH560 coupling agent, KH570 coupling agent, KH792 coupling agent and DL602 coupling agent. In this way, the mechanical strength, electrical properties and weather resistance of the epoxy resin adhesive can be further improved.

In order to further improve the treatment effect of the heat treatment, eliminate the stress of the epoxy resin adhesive, and improve the performance of the epoxy resin adhesive, in one embodiment, the temperature of the heat treatment is 100°C to 150°C, for example, the temperature of the heat treatment is 100°C , 110°C, 120°C, 130°C, 140°C or 150°C. For example, the time of the heat treatment is 2.0h˜6.0h; for example, the time of the heat treatment is 2.0h, 2.5h, 3.0h, 3.50h, 4.0h, 4.5h, 5.0h, 5.5h or 6.0h. In this way, the treatment effect of the heat treatment can be further improved, the stress of the epoxy resin adhesive can be eliminated, and the performance of the epoxy resin adhesive can be improved.

S130, dipping at least two layers of the low-k polymer porous membrane 110 stacked in layers into the epoxy resin adhesive to perform a lamination operation, so as to form dipping inside and outside of each layer of the low-k polymer porous membrane 110 The adhesive layer 120 is used to obtain a preliminary composite film; the preliminary composite film is cured to obtain the high-frequency composite material 10 .

In this way, the present invention uses the low-k polymer porous film 110 as a reinforcing material to improve the mechanical strength, compressive strength and tensile strength of the high-frequency composite material 10, and reduce the dielectric constant and dielectric loss of the high-frequency composite material 10. , using the impregnated adhesive layer 120 as an adhesive to increase the adhesive force between two adjacent low-k polymer porous membranes 110, so as to make the hierarchical structure firmly bonded to obtain low dielectric constant, low dielectric loss, High frequency composite material 10 with high mechanical strength, high compressive strength and high tensile strength. Then, the cross-linking effect of the impregnating adhesive layer 120 is improved through curing treatment, and the mechanical strength, heat resistance and wear resistance of the impregnating adhesive layer 120 are improved.

In one embodiment, the low-k polymer porous membrane 110 is a fiber woven membrane or a hollow fiber membrane. In this way, the dielectric constant and dielectric loss of the high-frequency composite material 10 can be further reduced. In order to further reduce the dielectric constant and dielectric loss of the high-frequency composite material 10 and improve the mechanical strength, compressive strength and tensile strength of the high-frequency composite material 10, in one embodiment, the material of the low-k polymer porous membrane 110 Including at least one of PTFE, PSF, PPO, PPS, PEEK, PEK, PEKK, PEKEKK, PEEKK, PI and MPI. In this way, the dielectric constant and dielectric loss of the high-frequency composite material 10 can be further reduced, and the mechanical strength, compressive strength and tensile strength of the high-frequency composite material 10 can be improved.

In order to further improve the treatment effect of the curing treatment, improve the cross-linking effect of the impregnating adhesive layer 120, and improve the mechanical strength, heat resistance and wear resistance of the impregnating adhesive layer 120, in one embodiment, the temperature of the curing treatment is 200° C. ~250°C, for example, the temperature of the curing treatment is 200°C, 210°C, 220°C, 230°C, 240°C or 250°C. For example, the curing time is 1 h to 24 h. For example, the curing time is 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h or 24 h. For example, the time of the curing treatment is preferably 2 h to 6 h. In this way, the treatment effect of the curing treatment can be further improved, the cross-linking effect of the impregnating adhesive layer 120 can be improved, and the mechanical strength, heat resistance and wear resistance of the impregnating adhesive layer 120 can be improved.

In order to further improve the adhesion performance of the surface of the low-k polymer porous membrane 110, and further improve the adhesion performance of the high-frequency composite material 10 and the conductive metal material, in one embodiment, after the operation of obtaining the high-frequency composite material 10, further Plasma treatment is performed on the high-frequency composite material 10, and new hydrophilic hydroxyl groups are introduced on the surface of the low-k polymer porous membrane 110 through the plasma treatment, so as to improve the wetting of the surface of the low-k polymer porous membrane 110 and forming some extremely tiny nano-scale grooves and protruding nano-scale short thin stripes on the low-k polymer porous membrane 110 to improve the surface of the low-k polymer porous membrane 110 The roughness can further improve the adhesion performance of the surface of the low-k polymer porous membrane 110, and further improve the adhesion performance of the high-frequency composite material 10 and the conductive metal material.

In order to further improve the treatment effect of the plasma treatment, in one embodiment, the operation of performing the plasma treatment on the low-k polymer porous membrane 110 is specifically: sequentially performing an ultrasonic cleaning operation on the low-k polymer porous membrane 110 and drying operation; set a conductive active mesh cover in the container, put the low-k polymer porous membrane 110 into the conductive active mesh cover, and then seal the container; vacuumize the container, Then, the processing gas is introduced into the container; the container is provided with a conductive container wall, and the plasma equipment transmits electricity to the conductive container wall and the conductive active mesh cover, so that the conductive container wall is an anode, so that the The conductive active mesh cover is a cathode, which ionizes the processing gas to generate plasma, and performs plasma processing on the low-k polymer porous membrane 110 .

In order to further improve the treatment effect of plasma treatment, in one embodiment, the plasma device is a DC plasma device or an AC plasma device, for example, the radio frequency output by the DC plasma device is 100MHz-100GHz, for example, the The radio frequency output by the DC plasma device is 50 GHz, for example, the microwave output by the AC plasma device is above 1 GHz. For example, the microwave output by the AC plasma device is 1 GHz, 5 GHz, 10 GHz, 50 GHz or 100 GHz. For example, the distance between the low dielectric constant base film and the conductive active mesh cover is 5 mm˜100 mm. For example, the distance between the low dielectric constant base film and the conductive active mesh is 50 mm. For example, the treatment pressure of the plasma treatment is 10 Pa to 500 Pa. For example, the treatment pressure of the plasma treatment is 2500Pa. For example, the treatment temperature of the plasma treatment is 50°C to 250°C. For example, the treatment temperature of the plasma treatment is 150°C. For example, the treatment time of the plasma treatment is 5 min to 5 h. For example, the treatment time of the plasma treatment is 2.5h. For example, the process gas includes at least one of argon, nitrogen, hydrogen, methane and oxygen. For example, the material of the conductive container wall includes at least one of stainless steel, copper, silver, nickel and aluminum. For example, the material of the conductive active mesh cover includes at least one of stainless steel, copper, silver, nickel and aluminum. In this way, the treatment effect of the plasma treatment can be further improved.

Compared with the prior art, the present invention has at least the following advantages:

The present invention uses the low-k polymer porous film 110 as a reinforcing material to improve the mechanical strength, compressive strength and tensile strength of the high-frequency composite material 10, and reduce the dielectric constant and dielectric loss of the high-frequency composite material 10; The impregnated adhesive layer 120 is used as an adhesive to increase the adhesive force between two adjacent low-k polymer porous films 110. The used impregnated adhesive layer 120 uses epoxy resin with low dielectric constant as the main raw material. The proportion of curing agent, foaming agent, thermal conductive agent, flame retardant and coupling agent is used to improve the heat resistance, corrosion resistance, thermal conductivity and flame retardant performance of the impregnated adhesive layer 120; The porous structure of the membrane 110 can further reduce its own dielectric constant and dielectric loss, and increase its adhesion with the impregnating glue layer 120 . In this way, the present invention can reduce the dielectric constant and dielectric loss of the high-frequency composite material 10 through the low-k polymer porous membrane 110 and the impregnated adhesive layer 120 , and can improve the mechanical strength, compressive strength and tensile strength of the high-frequency composite material 10 . Tensile strength, heat resistance, corrosion resistance, thermal conductivity and flame retardant properties.

The following is the specific example part

Example 1

S111, adding nano-boron nitride powder to a sodium chloride aqueous solution with a concentration of 0.5 wt % to prepare a boron nitride mixed solution with a concentration of 5 mg/mL; The mixed solution is subjected to ultrasonic dispersion operation, so that the nano-boron nitride powder is uniformly dispersed in the liquid components to obtain a nano-boron nitride dispersion solution.

S121, coupling 100g epoxy resin with epoxy equivalent of 0.20, 30g phthalic anhydride, 5g N,N'-dinitrosopentamethylenetetramine, 8g dimethyl methyl phosphate, and 2g KH570 The premix is mixed with 3 g of nano boron nitride dispersion liquid, and stirred evenly to obtain a premix; the premix is heat-treated at a temperature of 120° C. for 4.0 h to obtain an epoxy resin adhesive.

S131, dipping two layers of the laminated PPO fiber woven film into the epoxy resin adhesive to perform a lamination operation to form an impregnated adhesive layer on the inside and outside of each layer of the PPO fiber woven film to obtain a preparatory composite film ; Under the temperature of 220 ℃, the prepared composite film is cured for 6 h to obtain the high-frequency composite material of Example 1.

A laminate was prepared by using the high-frequency composite material of Example 1, and copper foil was pressed onto one side of the laminate to obtain a high-frequency circuit substrate.

Example 2

S112, adding nano-boron nitride powder to a sodium chloride aqueous solution with a concentration of 2.5 wt % to prepare a boron nitride mixed solution with a concentration of 20 mg/mL; The mixed solution is subjected to ultrasonic dispersion operation, so that the nano-boron nitride powder is uniformly dispersed in the liquid components to obtain a nano-boron nitride dispersion solution.

S122, mix 100g epoxy resin with epoxy equivalent of 0.30, 80g maleic anhydride, 20g azobisisobutyronitrile, 16g dimethyl methyl phosphate, 4g KH560 coupling agent and 13g nano-boron nitride dispersion liquid Mixing and stirring uniformly to obtain a premix; heat treatment of the premix at a temperature of 140° C. for 3.0 h to obtain an epoxy resin adhesive.

S132, dipping two layers of the laminated PSF fiber woven film into the epoxy resin adhesive to perform a lamination operation to form an impregnated adhesive layer on the inside and outside of each layer of the PSF fiber woven film to obtain a preparatory composite film ; Under the temperature of 240 ℃, the prepared composite film is cured for 2 h to obtain a high-frequency composite material.

A laminate was prepared by using the high-frequency composite material of Example 2, and a copper foil was pressed onto one side of the laminate to obtain a high-frequency circuit substrate.

Example 3

S113, adding nano-boron nitride powder to a sodium chloride aqueous solution with a concentration of 1.5 wt % to prepare a boron nitride mixed solution with a concentration of 12 mg/mL; The mixed solution is subjected to ultrasonic dispersion operation, so that the nano-boron nitride powder is uniformly dispersed in the liquid components to obtain a nano-boron nitride dispersion solution.

S123, mix 100g epoxy resin with epoxy equivalent of 0.25, 60g sebacic acid dihydrazide, 13g azodicarbonamide, 12g dimethyl methyl phosphate, 3g KH550 coupling agent and 6g nano boron nitride dispersion liquid Mixing and stirring uniformly to obtain a premix; heat treatment of the premix at a temperature of 130° C. for 4.0 h to obtain an epoxy resin adhesive.

S133, dipping the two layers of the laminated PTFE fiber woven film into the epoxy resin adhesive to perform a lamination operation to form an impregnated adhesive layer inside and outside each layer of the PTFE fiber woven film to obtain a preparatory composite film ; Under the temperature of 230 ℃, the prepared composite film is cured for 4 h to obtain a high-frequency composite material.

A laminate was prepared by using the high-frequency composite material of Example 3, and copper foil was pressed onto one side of the laminate to obtain a high-frequency circuit substrate.

Example 4

S114, adding nano-boron nitride powder to a sodium chloride aqueous solution with a concentration of 0.1 wt % to prepare a boron nitride mixed solution with a concentration of 1 mg/mL; The mixed solution is subjected to ultrasonic dispersion operation, so that the nano-boron nitride powder is uniformly dispersed in the liquid components to obtain a nano-boron nitride dispersion solution.

S124, 100g epoxy resin with epoxy equivalent of 0.15, 5g 3,3',4,4'-benzophenone tetraacid dianhydride, 0.5g p-toluenesulfonyl hydrazide, 5g dimethyl methyl phosphate, 0.5g g DL602 coupling agent and 1 g of nano-boron nitride dispersion are mixed and stirred evenly to obtain a premix; the premix is heat-treated at a temperature of 100° C. for 6.0 hours to obtain an epoxy resin adhesive.

S134, dipping the three-layered PEEK hollow fiber membranes in the epoxy resin adhesive to perform a lamination operation to form an impregnated adhesive layer on the inside and outside of each layer of the PEEK hollow fiber membranes to obtain a preparatory composite membrane ; Under the temperature of 200 ℃, the preparatory composite film is cured for 24 h to obtain a high-frequency composite material.

A laminate was prepared by using the high-frequency composite material of Example 4, and copper foil was pressed onto one side of the laminate to obtain a high-frequency circuit substrate.

Example 5

S115, adding nano-boron nitride powder to a sodium chloride aqueous solution with a concentration of 5.0 wt % to prepare a boron nitride mixed solution with a concentration of 100 mg/mL; The mixed solution is subjected to ultrasonic dispersion operation, so that the nano-boron nitride powder is uniformly dispersed in the liquid components to obtain a nano-boron nitride dispersion solution.

S125, mix 100g epoxy resin with epoxy equivalent of 0.50, 130g polyazelaic anhydride, 25g 4,4'-oxobisbenzenesulfonyl hydrazide, 20g dimethyl methyl phosphate, 5g KH792 coupling agent and 15g nanometer The boron nitride dispersions were mixed and stirred uniformly to obtain a premix; the premix was heat-treated at a temperature of 150° C. for 2.0 h to obtain an epoxy resin adhesive.

S135, dipping the three-layered PPS hollow fiber membranes in the epoxy resin adhesive to perform a lamination operation to form an impregnated adhesive layer on the inside and outside of each layer of the PPS hollow fiber membranes to obtain a preparatory composite membrane ; Under the temperature of 250°C, the preparatory composite film is cured for 1 h to obtain a high-frequency composite material.

A laminate was prepared by using the high-frequency composite material of Example 5, and a copper foil was pressed onto one side of the laminate to obtain a high-frequency circuit substrate.

Comparative Example 1

Dip the two-layer laminated PTFE film in a common epoxy resin adhesive for lamination operation to form an impregnated adhesive layer on the inside and outside of each layer of the PTFE film to obtain a preparatory composite film; at a temperature of 230 ° C The prepared composite film was cured for 4 hours to obtain a high-frequency composite material.

A laminate was prepared by using the high-frequency composite material of Comparative Example 1, and copper foil was pressed onto one side of the laminate to obtain a high-frequency circuit substrate.

The performance tests were carried out on the high-frequency circuit substrates prepared by using the high-frequency composite materials of Examples 1 to 5 and Comparative Example 1, and the results are shown in Table 1.

Table 1

It can be seen from Table 1 that, compared with the high-frequency circuit substrate prepared by the high-frequency composite material of Comparative Example 1, the high-frequency circuit substrate prepared by using the high-frequency composite material of Examples 1 to 5 has better dielectric properties, resistance to Thermal performance, thermal conductivity and flame retardant performance, its dielectric constant is in the range of 2.8 to 3.2 (28GHz); the dielectric loss is less than 0.001 (28GHz), it is used in high-frequency electronic materials, which can improve the integration of the device and reduce the delay time. , reducing crosstalk and energy consumption, and has extremely high application prospects in high-frequency electronic materials above 28GHz.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. The high-frequency composite material is characterized by comprising at least two layers of laminated low-k polymer porous membranes and an impregnation glue layer which permeates into the low-k polymer porous membranes in an impregnation mode and is attached to the outer sides of the low-k polymer porous membranes;

the impregnating glue layer comprises the following components in parts by mass: 100 parts of epoxy resin, 5-130 parts of curing agent, 0.5-25 parts of foaming agent, 1-15 parts of heat conducting agent, 5-20 parts of flame retardant and 0.5-5 parts of coupling agent.

2. The high-frequency composite material according to claim 1, wherein the material of the low-k polymer porous membrane includes at least one of PTFE, PSF, PPO, PPS, PEEK, PEK, PEKK, PEEKK, PI, and MPI.

3. The high-frequency composite material according to claim 1, wherein the epoxy resin has an epoxy equivalent of 0.15 to 0.50.

4. The high frequency composite according to claim 1, wherein the curing agent is a high temperature curing agent having a curing temperature of more than 100 ℃.

5. The high frequency composite according to claim 1, wherein the blowing agent comprises at least one of azodicarbonamide, azobisisobutyronitrile, N '-dinitrosopentamethylenetetramine, 4' -oxybis-benzenesulfonylhydrazide and p-toluenesulfonylhydrazide.

6. The high-frequency composite material according to claim 1, wherein the heat conductive agent comprises a nano boron nitride dispersion liquid highly dispersed by dissociation in a liquid component.

7. The high-frequency composite material according to claim 1, wherein the flame retardant comprises dimethyl methylphosphonate; or the coupling agent comprises a silane coupling agent.

8. The preparation method of the high-frequency composite material is characterized by comprising the following steps of:

mixing epoxy resin, a curing agent, a foaming agent, a flame retardant, a coupling agent and a heat conducting agent, and uniformly stirring to obtain a premix; carrying out heat treatment on the premix to obtain an epoxy resin adhesive; wherein the mass ratio of the epoxy resin, the curing agent, the foaming agent, the heat conducting agent, the flame retardant and the coupling agent is 100: (5-130): (0.5-25): (1-15): (5-20): (0.5 to 5);

dipping at least two layers of laminated low-k polymer porous membranes into the epoxy resin adhesive for lamination so as to form dipping glue layers inside and outside each layer of the low-k polymer porous membranes to obtain a prepared composite membrane; and curing the prepared composite film to obtain the high-frequency composite material.

9. The method for preparing a high-frequency composite material according to claim 8, wherein the temperature of the heat treatment is 100 ℃ to 150 ℃, and the time of the heat treatment is 2.0h to 6.0 h; or the temperature of the curing treatment is 200-250 ℃, and the time of the curing treatment is 1-24 h.

10. The method for preparing a high-frequency composite material according to claim 8, wherein before the operation of mixing the epoxy resin, the curing agent, the foaming agent, the flame retardant, the coupling agent and the heat conducting agent, nano boron nitride powder is further added to a liquid component to obtain a boron nitride mixed solution; and then carrying out ultrasonic dispersion operation on the boron nitride mixed solution so as to uniformly disperse the nano boron nitride powder in the liquid component to obtain the heat-conducting agent.

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