CN118879026A - A high thermal conductivity and low dielectric epoxy resin composite material and preparation method thereof - Google Patents

Abstract

The invention discloses a high thermal conductivity and low dielectric epoxy resin composite material and a preparation method thereof, and relates to the technical field of electronic packaging materials. The composite material includes the following components by weight: 80-120 parts of epoxy resin, 5-80 parts of thermally conductive insulating powder, 0-30 parts of ball milling aid, 5-70 parts of hollow glass microspheres or polyhedral oligomeric silsesquioxanes, 25-80 parts of curing agent and 1-10 parts of curing accelerator. The present invention also provides a preparation method for the above-mentioned composite material. The present invention synergistically utilizes the advantages of the high thermal conductivity of boron nitride and the low dielectric constant of hollow glass microspheres, so that the epoxy resin composite material has the performance of high thermal conductivity and low dielectric constant at the same time, effectively solving the problem of high thermal conductivity and low dielectric compromise in electronic packaging.

Description

A high thermal conductivity and low dielectric epoxy resin composite material and preparation method thereof

Technical Field

The invention relates to the technical field of electronic packaging materials, and in particular to a high thermal conductivity and low dielectric epoxy resin composite material and a preparation method thereof.

Background Art

The demand for miniaturized and highly integrated electronic devices has been increasing significantly in recent years, and there are higher requirements for fast signal transmission and fast heat dissipation. It is difficult for many current electronic packaging products to meet both high thermal conductivity and low dielectric constant at the same time, because this is a trade-off. Existing technologies all use single fillers to fill epoxy resins, such as boron nitride, silicon nitride, aluminum oxide, and graphene, but single fillers are difficult to meet both high thermal conductivity and low dielectric constant, and graphene can even conduct electricity, which cannot meet the requirements of specific fields such as insulation; some people also use direct current and magnetic fields to induce boron nitride alignment and assembly, but this method is more cumbersome and is not suitable for epoxy resin adhesives that are not suitable for use at any time.

Summary of the invention

In order to solve the above technical problems, the purpose of the present invention is to provide a high thermal conductivity and low dielectric constant epoxy resin composite material and a preparation method thereof, which synergistically utilizes the advantages of high thermal conductivity of boron nitride and low dielectric constant of hollow glass microspheres, so that the epoxy resin composite material has the properties of high thermal conductivity and low dielectric constant at the same time, effectively solving the problem of high thermal conductivity and low dielectric compromise in electronic packaging.

The technical solution of the present invention to solve the above technical problems is as follows: a high thermal conductivity and low dielectric epoxy resin composite material is provided, comprising the following components in parts by weight: 80-120 parts of epoxy resin, 5-80 parts of thermal conductive insulating powder, 0-30 parts of ball milling aid, 5-70 parts of hollow glass microspheres or polyhedral oligomeric silsesquioxane, 25-80 parts of curing agent and 1-10 parts of curing accelerator.

Furthermore, the following components are included in parts by weight: 100 parts of epoxy resin, 30 parts of thermally conductive insulating powder, 15 parts of ball milling aid, 10 parts of hollow glass microspheres, 75 parts of curing agent and 2 parts of curing accelerator.

Furthermore, the thermally conductive insulating powder is at least one of boron nitride, aluminum nitride, silicon carbide, magnesium oxide and zinc oxide.

Furthermore, the ball milling aid is polyethyleneimine.

Furthermore, the curing agent is at least one of methylhexahydrophthalic anhydride, 2-ethyl-4-methylimidazole and 4,4'-diaminodiphenylmethane.

Furthermore, the curing accelerator is at least one of 2,4,6-tris(dimethylaminomethylphenol)phenol, phthalamidine and phthalic acid.

The beneficial effects of the technical solution of the present invention are: boron nitride has a high in-plane thermal conductivity (200W/m·K), and among many inorganic fillers, it has a very low dielectric constant. It can greatly improve the thermal conductivity of epoxy resin when used as a filler for epoxy resin; at the same time, the second material, hollow glass microspheres, is used. The material is hollow inside and has a dielectric constant slightly higher than that of air. Hollow glass microspheres can play a role in volume exclusion, thereby increasing the phonon transmission channel and building a phonon transmission network, greatly improving thermal conductivity. Moreover, after adding hollow glass microspheres, the dielectric constant and viscosity of epoxy resin can be reduced, solving the problem that the dielectric constant of the system is too high and the viscosity rises sharply at high filler concentrations.

The present invention also provides a method for preparing the above-mentioned high thermal conductivity and low dielectric epoxy resin composite material, which comprises the following steps in sequence:

(1) mixing a thermally conductive insulating powder, a ball milling aid and deionized water and then ball milling;

(2) adding epoxy resin and curing agent, as well as hollow glass microspheres or polyhedral oligomeric silsesquioxane, stirring in a constant temperature water bath, then ultrasonically treating, adding a curing accelerator and mixing evenly, and then vacuum degassing;

(3) Pour the mixture into a preheated mold, let it stand at 70-90° C. for 1-3 h, then heat it to 110-150° C. and let it stand for 1-3 h. After cooling, take it out to obtain a high thermal conductivity and low dielectric epoxy resin composite material.

Furthermore, in step (1), the mass volume ratio of the thermally conductive insulating powder and deionized water is 3g:80-120mL.

Furthermore, in step (1), ball milling is performed at 400-600 r/min for 10-30 h.

Furthermore, in step (2), stirring is performed at 400-600 r/min in a constant temperature water bath at 50-70° C. for 5-15 min.

Furthermore, in step (2), ultrasonic treatment is performed at a temperature of 50-70° C. and a power of 110-130 W for 20-40 min.

Furthermore, in step (2), the mixture is mixed uniformly under stirring at 400-600 r/min for 50-70 min.

Furthermore, in step (2), during vacuum degassing, the above system is placed in a dryer and evacuated. During vacuum evacuation, the viscosity of the system increases due to a drop in temperature, thereby causing the vacuum evacuation rate to decrease. Therefore, after 10 minutes of evacuation, the solution needs to be placed back in a water bath and heated before evacuation. No stirring is required, and this process is repeated 2-3 times until there are no bubbles.

The present invention has the following beneficial effects:

1. The present invention synergistically utilizes the advantages of high thermal conductivity of boron nitride and low dielectric constant of hollow glass microspheres, so that the epoxy resin has the properties of high thermal conductivity and low dielectric constant at the same time.

2. Hollow glass microspheres can play a role of volume exclusion in the system, making the boron nitride links more tightly and forming an effective heat conduction path; at the same time, hollow glass microspheres can also play a role in reducing viscosity.

3. The present invention can obtain a relatively high thermal conductivity without surface modification of the filler, and the preparation method is simple.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a graph showing the change in thermal conductivity of epoxy resin with only boron nitride added;

FIG2 is a graph showing the change in thermal conductivity of epoxy resin with addition of boron nitride and hollow glass microspheres as dual fillers;

FIG3 is a graph showing the change in dielectric constant of epoxy resin with only boron nitride added;

FIG4 is a graph showing the change in dielectric constant of epoxy resin with addition of boron nitride and hollow glass microspheres as dual fillers;

FIG5 is a viscosity comparison chart of adding boron nitride and boron nitride + hollow glass microspheres dual fillers.

DETAILED DESCRIPTION

The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific conditions are specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

Some of the raw materials used in the examples of the present invention are as follows:

Epoxy resin: F170, Nanya Electronic Materials (Kunshan); E51, Vigorit; E44, commercially available.

Hollow glass microspheres: 16μm, foreign international.

Boron nitride: 30μm, 3M Chemical.

Curing agent, curing accelerator: Inok

Example 1

A high thermal conductivity and low dielectric epoxy resin composite material comprises the following components in parts by weight: 100 parts of F170 epoxy resin, 30 parts of thermal conductive insulating powder boron nitride, 15 parts of ball milling aid polyethyleneimine, 10 parts of hollow glass microspheres, 75 parts of curing agent and 1 part of curing accelerator 2,4,6-tris(dimethylaminomethylphenol)phenol.

The preparation method comprises the following steps in sequence:

(1) The thermal conductive insulating powder, ball milling aid and deionized water were mixed and ball milled at 450 r/min for 26 h; the mass volume ratio of the thermal conductive insulating powder and deionized water was 3 g:100 mL;

(2) adding epoxy resin, curing agent, and hollow glass microspheres, stirring at 500 r/min for 5-15 min in a 60°C constant temperature water bath, then ultrasonically treating at 60°C and 120 W for 30 min, adding a curing accelerator, stirring at 500 r/min for 60 min to mix evenly, and then vacuum degassing;

(3) Pour the mixture into a mold preheated to 80° C., let it stand at 80° C. for 2 h, then heat it to 120° C. and let it stand for 2 h. After cooling, take it out to obtain a high thermal conductivity and low dielectric epoxy resin composite material.

Example 2

A high thermal conductivity and low dielectric epoxy resin composite material comprises the following components in parts by weight: 80 parts of E51 epoxy resin, 5 parts of thermal conductive insulating powder boron nitride, 2.5 parts of ball milling aid polyethyleneimine, 5 parts of hollow glass microspheres, 25 parts of curing agent methyl hexahydrophthalic anhydride and 2 parts of curing accelerator 2,4,6-tris(dimethylaminomethylphenol)phenol.

The preparation method comprises the following steps in sequence:

(1) The thermal conductive insulating powder, ball milling aid and deionized water were mixed and ball milled at 400 r/min for 10 h; the mass volume ratio of the thermal conductive insulating powder and deionized water was 3 g:80 mL;

(2) adding epoxy resin, curing agent and hollow glass microspheres, stirring at 400 r/min for 5 min in a 50°C constant temperature water bath, then ultrasonically treating at 50°C and 110 W for 20 min, adding curing accelerator and stirring at 400 r/min for 50 min to mix evenly, and then vacuum degassing;

(3) Pour the mixture into a mold preheated to 70°C, let it stand at 70°C for 1 hour, then heat it to 110°C and let it stand for 1 hour. After cooling, take it out to obtain a high thermal conductivity and low dielectric epoxy resin composite material.

Example 3

A high thermal conductivity and low dielectric epoxy resin composite material comprises the following components in parts by weight: 120 parts of E44 epoxy resin, 80 parts of thermal conductive insulating powder boron nitride, 30 parts of ball milling aid polyethyleneimine, 70 parts of hollow glass microspheres, 80 parts of curing agent methyl hexahydrophthalic anhydride and 10 parts of curing accelerator 2,4,6-tris(dimethylaminomethylphenol)phenol.

The preparation method comprises the following steps in sequence:

(1) The thermal conductive insulating powder, ball milling aid and deionized water were mixed and ball milled at 600 r/min for 30 h; the mass volume ratio of the thermal conductive insulating powder and deionized water was 3 g:120 mL;

(2) adding epoxy resin, curing agent, and hollow glass microspheres and stirring at 600 r/min for 15 min in a 70°C constant temperature water bath, then ultrasonically treating at 70°C and 130 W for 40 min, adding a curing accelerator and stirring at 600 r/min for 70 min to mix evenly, and then vacuum degassing;

(3) Pour the mixture into a mold preheated to 90° C., let it stand at 90° C. for 3 h, then heat it to 150° C. and let it stand for 3 h. After cooling, take it out to obtain a high thermal conductivity and low dielectric epoxy resin composite material.

Example 4

A high thermal conductivity and low dielectric epoxy resin composite material comprises the following components in parts by weight: 90 parts of F170 epoxy resin, 20 parts of thermal conductive insulating powder aluminum nitride, 10 parts of polyhedral oligomeric silsesquioxane, 40 parts of curing agent 2-ethyl-4-methylimidazole and 4 parts of curing accelerator benzodicarboxamidine.

Example 5

A high thermal conductivity and low dielectric epoxy resin composite material comprises the following components by weight: 110 parts of E51 epoxy resin, 40 parts of thermal conductive insulating powder silicon carbide, 30 parts of hollow glass microspheres, 60 parts of curing agent 4,4'-diaminodiphenylmethane and 6 parts of curing accelerator phthalic acid.

Example 6

A high thermal conductivity and low dielectric epoxy resin composite material comprises the following components in parts by weight: 100 parts of E44 epoxy resin, 60 parts of thermal conductive insulating powder magnesium oxide, 20 parts of hollow glass microspheres, 70 parts of curing agent methyl hexahydrophthalic anhydride and 7 parts of curing accelerator 2,4,6-tris(dimethylaminomethylphenol)phenol.

Example 7

A high thermal conductivity and low dielectric epoxy resin composite material comprises the following components in parts by weight: 90 parts of F170 epoxy resin, 40 parts of thermal conductive insulating powder zinc oxide, 30 parts of polyhedral oligomeric silsesquioxane, 50 parts of curing agent 2-ethyl-4-methylimidazole and 5 parts of curing accelerator benzodicarboxamidine.

Example 8

A high thermal conductivity and low dielectric epoxy resin composite material comprises the following components in parts by weight: 100 parts of E51 epoxy resin, 30 parts of thermal conductive insulating powder boron nitride, 15 parts of ball milling aid polyethyleneimine, 20 parts of polyhedral oligomeric silsesquioxane, 60 parts of curing agent 4,4'-diaminodiphenylmethane and 7 parts of curing accelerator phthalic acid.

Test Example 1 Thermal Conductivity

The thermal conductivity of epoxy resin (EP) with only boron nitride (BN) filler and with hollow glass microspheres (HGM) and boron nitride dual fillers is compared. The thermal conductivity change graph of epoxy resin with only boron nitride is shown in Figure 1, and the thermal conductivity change graph of epoxy resin with boron nitride and hollow glass microsphere dual fillers is shown in Figure 2.

As shown in Figure 1, when only boron nitride is added to epoxy resin without hollow glass microspheres, its thermal conductivity increases with the increase of filler, and the thermal conductivity of 40% boron nitride is 1.496W/mK. As shown in Figure 2, when hollow glass microspheres and boron nitride are added to epoxy resin, its thermal conductivity also increases with the increase of filler. By comparing Figures 1 and 2, it can be seen that at the same filler content, the epoxy resin with only boron nitride has only 1.496W/mK at a filler content of 40%, while the epoxy resin with hollow glass microspheres and boron nitride has a thermal conductivity of 3.104W/mK at a filler content of 40%, which is 207% higher than that. This shows that hollow glass microspheres can play a role in volume exclusion, thereby increasing phonon transmission channels and building a phonon transmission network, greatly improving thermal conductivity.

Test Example 2 Dielectric Properties

The dielectric properties of epoxy resin (EP) with only boron nitride (BN) filler and with both hollow glass microspheres (HGM) and boron nitride fillers are compared. The dielectric constant change graph of epoxy resin with only boron nitride is shown in Figure 3, and the dielectric constant change graph of epoxy resin with both boron nitride and hollow glass microsphere fillers is shown in Figure 4.

As shown in Figure 3, the dielectric constant of epoxy resin with only boron nitride added is between 4 and 8, and the addition of inorganic particles will cause more electronic polarization and interface defects, so the addition of boron nitride will inevitably increase the dielectric constant of epoxy resin. After adding a series of boron nitrides, the dielectric constant of epoxy resin continues to increase. As can be seen from Figure 4, the addition of hollow glass microspheres has a reducing effect on the dielectric constant of epoxy resin, because at the same filler content, the dielectric constant of the addition of hollow glass microspheres and boron nitride is lower than the dielectric constant of the addition of boron nitride alone, which is enough to show that the addition of hollow glass microspheres can reduce the dielectric constant of the system.

Test Example 3 Viscosity Performance

This test example uses F170 bisphenol F resin, and the ratio of bisphenol F resin to curing agent is 100:45. The viscosity performance of adding only boron nitride (BN) filler and adding hollow glass microspheres (HGM) and boron nitride dual fillers to the epoxy resin is compared. The viscosity comparison chart of adding boron nitride and boron nitride + hollow glass microsphere dual fillers is shown in Figure 5.

Hollow glass microspheres are spherical at the microscopic scale, just like the sphere in the middle of a bearing can reduce friction. At the same filler content, replacing boron nitride with a portion of hollow glass microspheres can reduce the viscosity of the system, thereby making the epoxy adhesive have better fluidity and can be used in more aspects. As shown in Figure 5, when the same mass fraction of boron nitride and boron nitride + hollow glass microspheres are added to the system, the viscosity of the latter is smaller, which proves that the addition of hollow glass microspheres can indeed reduce the viscosity of the system.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. A high thermal conductivity and low dielectric epoxy resin composite material, characterized in that it comprises the following components in parts by weight: 80-120 parts of epoxy resin, 5-80 parts of thermal conductive insulating powder, 0-30 parts of ball milling aid, 5-70 parts of hollow glass microspheres or polyhedral oligomeric silsesquioxane, 25-80 parts of curing agent and 1-10 parts of curing accelerator. 2. The high thermal conductivity and low dielectric epoxy resin composite material as described in claim 1 is characterized in that it comprises the following components in parts by weight: 100 parts of epoxy resin, 30 parts of thermal conductive insulating powder, 15 parts of ball milling aid, 10 parts of hollow glass microspheres, 75 parts of curing agent and 2 parts of curing accelerator. 3. The high thermal conductivity and low dielectric epoxy resin composite material according to claim 1, characterized in that the thermally conductive insulating powder is at least one of boron nitride, aluminum nitride, silicon carbide, magnesium oxide and zinc oxide. 4 . The high thermal conductivity and low dielectric epoxy resin composite material according to claim 1 , wherein the ball milling aid is polyethyleneimine. 5 . The high thermal conductivity and low dielectric epoxy resin composite material according to claim 1 , wherein the curing agent is at least one of methyl hexahydrophthalic anhydride, 2-ethyl-4-methylimidazole and 4,4′-diaminodiphenylmethane. 6. The high thermal conductivity and low dielectric epoxy resin composite material according to claim 1, characterized in that the curing accelerator is at least one of 2,4,6-tris(dimethylaminomethylphenol)phenol, phthalamidine and phthalic acid. 7. The method for preparing the high thermal conductivity and low dielectric epoxy resin composite material according to any one of claims 1 to 6, characterized in that it comprises the following steps in sequence: (1) mixing a thermally conductive insulating powder, a ball milling aid and deionized water and then ball milling; (2) adding epoxy resin and curing agent, as well as hollow glass microspheres or polyhedral oligomeric silsesquioxane, stirring in a constant temperature water bath, then ultrasonically treating, adding a curing accelerator and mixing evenly, and then vacuum degassing; (3) Pour the mixture into a preheated mold, let it stand at 70-90° C. for 1-3 h, then heat it to 110-150° C. and let it stand for 1-3 h. After cooling, take it out to obtain a high thermal conductivity and low dielectric epoxy resin composite material. 8. The method for preparing a high thermal conductivity and low dielectric epoxy resin composite material according to claim 7, characterized in that in step (1), the mass volume ratio of the thermally conductive insulating powder and deionized water is 3g:80-120mL. 9. The method for preparing a high thermal conductivity and low dielectric epoxy resin composite material according to claim 5, characterized in that in step (1), ball milling is performed at 400-600 r/min for 10-30 hours. 10. The method for preparing a high thermal conductivity and low dielectric epoxy resin composite material according to claim 5, characterized in that in step (2), stirring is performed at 400-600 r/min for 5-15 min in a constant temperature water bath at 50-70°C.