CN116042132A

CN116042132A - Three-dimensional framework material, electronic packaging adhesive and preparation method and application thereof

Info

Publication number: CN116042132A
Application number: CN202310158330.2A
Authority: CN
Inventors: 李秋影; 赵菊兰
Original assignee: East China University of Science and Technology
Current assignee: East China University of Science and Technology
Priority date: 2023-02-23
Filing date: 2023-02-23
Publication date: 2023-05-02

Abstract

The invention discloses a three-dimensional framework material, electronic packaging adhesive and preparation methods and applications thereof. The preparation of the three-dimensional framework material comprises the following steps: (1) After the adhesive solution and the heat conducting filler are mixed for the first time, dispersing liquid is dispersed; (2) And carrying out secondary mixing on the dispersion liquid and the pyrolysis material, and then drying to obtain the three-dimensional framework material. The preparation method is simple, the production efficiency is high, and the prepared electronic packaging adhesive can simultaneously meet the requirements of high heat conductivity, high waterproof performance and high electrical insulation performance.

Description

Three-dimensional framework material, electronic packaging adhesive and preparation method and application thereof

Technical Field

The invention relates to a three-dimensional framework material, electronic packaging adhesive, and a preparation method and application thereof.

Background

The electronic packaging adhesive needs to rapidly transfer heat generated by the operation of each component, and in the working process of the components, the generated heat is also continuously increased along with the increase of working time, if the generated heat cannot be timely transferred out, heat accumulation can be caused, the internal temperature of the components is rapidly increased, and the operation reliability and the service life of the components are affected. In addition, if the electronic packaging adhesive has no good waterproof performance, the electronic packaging adhesive is easy to absorb water and wet in the use process, the electrical insulation performance is damaged, the electric leakage phenomenon occurs, the energy loss is caused, the short circuit phenomenon also occurs, and the device is damaged destructively. Therefore, the heat conducting property of the electronic packaging adhesive is improved, the electronic packaging adhesive is endowed with excellent waterproof property and electrical insulation property, the operation reliability of components is improved, the service life of the components is prolonged, and the electronic packaging adhesive has very important commercial value.

Chinese patent CN110358255B discloses a method for preparing a polymer-based composite heat conductive material, which comprises mixing and pressurizing a heat conductive filler and a pyrolysis material to obtain a pressed product, performing a heat treatment on the pressed product to remove the pyrolysis material to obtain a three-dimensional skeleton, and finally filling the three-dimensional skeleton with a polymer material to obtain a composite material. Chinese patent CN111019290B provides a method for preparing a substrate material for high thermal conductivity electronic packaging, which comprises the steps of foaming organic polyurethane into a porous alumina ceramic mesh by impregnation method, using the porous alumina ceramic mesh as a thermal conductive skeleton of an epoxy resin-based material, modifying the surface of the porous alumina ceramic mesh by a silane coupling agent, filling epoxy resin, encapsulating, and curing at high temperature to form a ceramic/resin composite substrate material with good thermal conductivity.

Although the above methods can prepare high heat conductive adhesives, some disadvantages still exist:

1. the three-dimensional network skeleton has low strength, is easy to crush or has complex preparation process and low production efficiency;

2. the heat conduction performance and the waterproof performance are mutually restricted in the construction of the three-dimensional network framework, and can not be simultaneously improved in the existing three-dimensional network;

3. the method has high requirements on equipment whether an external pressure method or a high-temperature sintering method; the former requires a large hydraulic press providing high pressure and the latter requires a high temperature furnace providing high temperature.

Therefore, the electronic packaging adhesive in the prior art still has the technical bottleneck that the heat conduction performance and the electric insulation performance are mutually restricted.

Disclosure of Invention

The invention provides a three-dimensional framework material, electronic packaging adhesive and a preparation method and application thereof, and aims to solve the problems that the three-dimensional network framework of the electronic packaging adhesive in the prior art is low in strength and cannot meet the requirements of high heat conduction performance, high waterproof performance and high electrical insulation performance.

The invention mainly adopts the following technical scheme to solve the technical problems:

the invention provides a preparation method of a three-dimensional framework material, which comprises the following steps:

(1) After the adhesive solution and the heat conducting filler are mixed for the first time, dispersing liquid is dispersed;

(2) And carrying out secondary mixing on the dispersion liquid and the pyrolysis material, and then drying to obtain the three-dimensional framework material.

By adopting the preparation method, the pyrolysis material and the heat conducting filler are uniformly distributed, and the adhesive is coated on the surfaces of the pyrolysis material and the heat conducting filler, so that the pyrolysis material and the heat conducting filler are bonded together to form a co-continuous structure. In the drying process, the pyrolysis material is heated and decomposed, gas generated at high temperature overflows, and only the heat-conducting filler and a small amount of adhesive for bonding the heat-conducting filler are remained, so that a porous three-dimensional framework is formed.

Meanwhile, the adhesive can permeate between adjacent heat-conducting fillers, so that the existence of gaps in the three-dimensional framework material caused by the appearance problem of the heat-conducting fillers is reduced, the introduction of more interfaces in the heat transmission process is avoided, phonon scattering at the interfaces is reduced, the heat conduction efficiency is improved, and the heat conduction performance is improved. In addition, the compact structure can also avoid the damage of the waterproof performance caused by the water entering holes to a great extent, so that the three-dimensional framework material is prevented from being affected by external water vapor, and the damage of the insulating performance caused by water absorption of the material is avoided.

In the present invention, the adhesive is preferably a thermoplastic resin adhesive.

Wherein the thermoplastic resin adhesive is preferably one or more of polyvinylidene fluoride, polyvinyl acetate, polyacrylate, polystyrene and polysulfone.

Wherein the molecular weight of the thermoplastic resin adhesive is preferably 15 to 70 ten thousand, more preferably 57 to 60 ten thousand.

In the present invention, the thermally conductive filler may be conventional in the art, preferably boron nitride, aluminum oxide, diamond, beryllium oxide, aluminum nitride, silicon carbide, silicon nitride or zinc oxide, more preferably boron nitride modified with a fluorine-containing silane coupling agent. The heat conductive filler serves to conduct away the generated heat.

Wherein the modification by the fluorine-containing silane coupling agent comprises the following steps: adding boron nitride into alkali liquor for heat treatment to obtain alkali-boron nitride powder; adding alkali-boron nitride powder into a solution containing the fluorine-containing silane coupling agent, and drying to obtain boron nitride modified by the fluorine-containing silane coupling agent.

The fluorine-containing silane coupling agent is used for carrying out surface modification on the heat conducting filler, so that the dispersion performance can be further improved, the waterproof performance is improved while the three-dimensional skeleton of the heat conducting filler is constructed, the electric insulation performance reduction caused by water absorption is avoided, the three-dimensional skeleton material has excellent heat conducting performance and electric insulation performance, and the application field of the heat conducting filler is enlarged.

In the present invention, those skilled in the art will recognize from the solution that it is generally desirable to dissolve the adhesive in a solvent that is preferably one or more of acetone, chloroform, ethanol and diethyl ether to form a homogeneous solution.

In the present invention, the pyrolyzing material includes an organic pyrolyzing material, which preferably includes polyvinyl alcohol, polypropylene or polycarbonate.

In the present invention, the pyrolyzing material includes an inorganic pyrolyzing material, and the inorganic pyrolyzing material preferably includes NH ₄ HCO ₃ Or (NH) ₄ ) ₂ CO ₃ 。

In the invention, the pyrolysis material does not react with the adhesive.

In the invention, the molecular particle diameter D90 of the pyrolysis material is 100-500 mu m.

In the present invention, the weight ratio of the adhesive to the heat conductive filler is preferably 1: (0.5 to 2), for example, 1:1 or 1:1.5.

in the present invention, the weight ratio of the adhesive to the pyrolyzed material is preferably 1: (2 to 5), for example, 1:2.5 or 1:3.

in the present invention, the concentration of the adhesive solution is preferably 30 to 60g/L, for example, 37.5g/L or 50g/L.

In the present invention, the purpose of the first mixing is to thoroughly mix the adhesive and the heat conductive filler to form a uniform viscous mixture, and the method of the first mixing may be conventional in the art, for example, stirring, and the stirring time may be enough to form a uniform viscous mixture.

In the present invention, the purpose of the second mixing is to thoroughly mix the dispersion and the pyrolyzed material to form a uniform viscous mixture. The second mixing method may be conventional in the art, for example stirring, for a period of time sufficient to form a homogeneous viscous mixture.

In the invention, the purpose of the drying is to decompose the pyrolysis material by heating to form a porous structure. The drying time is that the pyrolysis material is completely decomposed.

In the present invention, the temperature of the drying is preferably 10 to 20 ℃ higher than the decomposition temperature of the pyrolysis material. The decomposition temperature refers to a temperature at which molecules of the pyrolysis material are decomposed into gases and the gases are allowed to escape the three-dimensional framework material.

At a suitable drying temperature, the pyrolysis material has a moderate decomposition rate, the size of pores left in the three-dimensional framework material is comparable to the intrinsic size of the pyrolysis material, and a uniform and continuous porous structure is left in the three-dimensional framework material.

Wherein when the pyrolysis material is NH ₄ HCO ₃ When the temperature of the drying is preferably 70 to 80 ℃.

The invention also provides the three-dimensional framework material prepared by the preparation method of the three-dimensional framework material.

The invention also provides a preparation method of the electronic packaging adhesive, which comprises the following steps: and immersing the three-dimensional framework material into a resin material and then curing.

Because the pyrolysis material occupies a large amount of space before drying, only a small amount of space is reserved for the heat-conducting filler, and the heat-conducting filler is easier to form a continuous structure to construct a heat-conducting passage. In the process of impregnating the resin material, the resin enters holes left after pyrolysis of the pyrolysis material to form a compact structure, and a three-dimensional framework structure formed by the heat conducting filler is arranged around the compact structure to form the electronic packaging adhesive with the three-dimensional continuous heat conducting network inside.

In the present invention, the resin material is preferably an epoxy resin material, more preferably an epoxy resin E-42.

In the present invention, the resin material preferably further includes one or more of a toughening agent, a curing agent and a diluent.

Wherein the diluent is preferably ethylene glycol diglycidyl ether having a formula of C ₁₀ H ₁₄ O ₄ 。

Wherein the toughening agent is preferably YM-004, the structural formula of the YM-004 is shown as formula 1, and the viscosity of the YM-004 is 55-95 mPa.s.

Wherein the curing agent is preferably methyl nadic anhydride, and the molecular formula of the methyl nadic anhydride is C ₁₀ H ₁₀ O ₃ The viscosity of the methyl nadic anhydride is 175-225 mPa.s.

Wherein the weight ratio of the epoxy resin E-42, the ethylene glycol diglycidyl ether, the YM-004 and the methyl nadic anhydride is preferably 100:20:10:75.

it is known to those skilled in the art that in order to remove air bubbles from the electronic packaging adhesive, it is also preferable to include a vacuum prior to the curing.

Wherein the evacuating preferably comprises sequentially performing a first evacuation, ultrasound and a second evacuation.

Wherein the temperature of the first vacuum is preferably 40-60 ℃, for example 50 ℃.

The time for the first vacuum is preferably 1 to 4 hours, for example 2 hours.

Wherein the time of the ultrasound is preferably 1 to 4 hours, for example 2 hours.

The time of the second vacuum is preferably 0.5 to 3 hours, for example 1 hour.

In the present invention, the curing temperature is preferably 100 to 150 ℃, for example 120 ℃.

In the present invention, the curing time is preferably 3 to 10 hours, for example, 6 hours.

The invention also provides the electronic packaging adhesive prepared by the preparation method of the electronic packaging adhesive.

The invention also provides an electronic packaging adhesive, which comprises a three-dimensional framework material and a resin material, wherein the three-dimensional framework material comprises an adhesive and a heat-conducting filler;

the three-dimensional framework material is of a porous structure, and the pore diameter of the porous structure is 100-500 mu m;

the resin material is filled in the porous structure of the three-dimensional framework material, and the density of the three-dimensional framework material is 1.4-1.5 g/cm ³ Wherein the pore size is 100 to 500 μm, meaning that 90% or more of the pore sizes in the porous structure are within the above range.

The inventor finds through multiple experiments that if the pore diameter of the porous structure is too small, the phenomenon that the resin material is difficult to impregnate completely easily occurs in the subsequent impregnation process, and the existence of gaps can influence the heat conducting performance of the porous structure; if the pore diameter of the porous structure is too large, the density of the heat conducting network is too small, so that the heat enhancement effect is poor.

The invention also provides application of the electronic packaging adhesive in electronic elements.

On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the invention.

The reagents and materials used in the present invention are commercially available.

The invention has the positive progress effects that:

in the prior art, in order to improve the heat conduction performance of the heat conduction filler and improve the dispersion performance of the heat conduction filler in a matrix, the heat conduction filler is subjected to surface modification treatment, and new groups introduced in the treatment process can cause the improvement of the hydrophilic performance of the heat conduction filler and destroy the waterproof performance of the three-dimensional framework material. According to the invention, the heat conducting filler is bonded by adding the adhesive, so that the three-dimensional network skeleton strength is improved, the use of large-scale pressurizing equipment is avoided, the equipment requirement is reduced, the method is more suitable for large-scale industrial production, and the problem of poor waterproof performance caused by surface modification treatment is solved.

Meanwhile, the pyrolysis material which can be decomposed by heating is adopted, so that the pyrolysis material can be directly removed in the drying process, the processes of subsequent washing, drying and the like are omitted, the production efficiency is improved, the loss of the heat conducting filler in the washing process is avoided, the utilization rate of raw materials can be improved, the cost is reduced, and the performance stability of the product is improved.

Drawings

Fig. 1 is a scanning electron microscope image of the electronic packaging adhesive of example 1.

Fig. 2 is a scanning electron microscope image of the electronic packaging adhesive of example 2.

Fig. 3 is a scanning electron microscope image of the electronic packaging adhesive of example 3.

Fig. 4 is a scanning electron microscope image at 1K magnification of the electronic packaging adhesive of comparative example 2.

Fig. 5 is a scanning electron microscope image at 4K magnification of the electronic packaging adhesive of comparative example 2.

FIG. 6 is a scanning electron microscope image of the skeletal material of example 4 after oven drying at 60 ℃.

FIG. 7 is a scanning electron microscope image of the skeletal material of example 5 after being dried at 70 ℃.

FIG. 8 is a scanning electron microscope image of the framework material of example 1 after drying at 80 ℃.

FIG. 9 is a scanning electron microscope image of the framework material of example 6 after drying at 90 ℃.

Fig. 10 is a scanning electron microscope image of the dried skeletal material of example 7.

FIG. 11 is a scanning electron microscope image of the dried skeletal material of example 8.

Detailed Description

The invention is further illustrated by means of the following examples, which are not intended to limit the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.

The boron nitride used in examples 1 to 8 and comparative examples 1 and 2 were each subjected to surface modification including the steps of:

adding 10g of boron nitride into 5mol/L NaOH solution, performing heat treatment at 80 ℃ for 48 hours to obtain alkali-boron nitride solution, and washing and drying to obtain alkali-boron nitride powder; adding tridecafluorooctyl triethoxysilane into the ethanol solution to form a solution, wherein the ethanol is as follows: water: the mass ratio of the tridecafluorooctyl triethoxysilane is 9:1:1, regulating the pH value of the solution to 4-6, adding the alkali-boron nitride powder into the solution, stirring for 6 hours to obtain surface modified boron nitride dispersion liquid, and washing and drying to obtain the surface modified boron nitride powder.

In the invention, PVDF is purchased from Suwei corporation of America, and the molecular weight of PVDF is 57-60 ten thousand; PS is purchased from Dongguan Haobang plastics company and has the molecular weight of 17-20 ten thousand; epoxy E-42 was purchased from Michelin corporation; ethylene glycol diglycidyl ether, YM-004, and methyl nadic anhydride were all purchased from electronic limited, chuzhou Hui Cheng.

In the present invention, the formulation mass ratio of the resin materials used in examples 1 to 8 and comparative examples 1 and 2 were: epoxy resin E-42: ethylene glycol diglycidyl ether: YM-004: methyl nadic anhydride=100:20:10:75.

Example 1

1. Three-dimensional framework material

0.75g PVDF was dissolved in 20ml acetone, stirred for 5min, 0.75g boron nitride was added thereto, and stirred for 1h to form a boron nitride dispersionAnd (3) liquid. Followed by addition of 3.5g NH ₄ HCO ₃ Stirring for 2 hours, putting into a mould to obtain a required shape, taking out, putting into an oven, and drying at 80 ℃ for 12 hours to obtain the three-dimensional framework material.

2. Electronic packaging adhesive

Immersing the dried framework material into a pre-prepared resin material, carrying out first vacuum drying at 50 ℃ for 2 hours, carrying out ultrasonic treatment after the first drying for 2 hours, carrying out second vacuum drying at 50 ℃ for 1 hour after ultrasonic treatment, and curing at 120 ℃ for 6 hours after the second drying to obtain the electronic packaging adhesive.

Example 2

1. Three-dimensional framework material

1.0g of PVDF was dissolved in 20ml of acetone, and after stirring for 5 minutes, 1.0g of boron nitride was added thereto, and stirring was carried out for 1 hour to form a boron nitride dispersion. Followed by addition of 3.0g NH ₄ HCO ₃ Stirring for 2h to obtain a required shape, putting into a mould, taking out, putting into an oven, and drying at 80 ℃ for 12h to obtain the three-dimensional framework material.

2. Electronic packaging adhesive

Example 3

1. Three-dimensional framework material

Will be 1.0gPVDF was dissolved in 20ml of acetone, and after stirring for 5min, 1.5g of boron nitride was added thereto, and stirred for 1h to form a boron nitride dispersion. Subsequently 2.5g NH was added ₄ HCO ₃ Stirring for 2h to obtain a required shape, putting into a mould, taking out, putting into an oven, and drying at 80 ℃ for 12h to obtain the three-dimensional framework material.

2. Electronic packaging adhesive

Example 4

1. Three-dimensional framework material

0.75g PVDF was dissolved in 20ml acetone, and after stirring for 5min, 0.75g boron nitride was added thereto, and stirring was carried out for 1h to form a boron nitride dispersion. Subsequently 3.5g (NH) ₄ ) ₂ CO ₃ Stirring for 2 hours, putting into a mould to obtain a required shape, taking out, putting into an oven, and drying at 60 ℃ for 12 hours to obtain the three-dimensional framework material.

2. Electronic packaging adhesive

Example 5

1. Three-dimensional framework material

0.75g PVDF was dissolved in 20ml acetone, and after stirring for 5min, 0.75g boron nitride was added thereto, and stirring was carried out for 1h to form a boron nitride dispersion. Followed by addition of 3.5g NH ₄ HCO ₃ Stirring for 2 hours, putting into a mould to obtain a required shape, taking out, putting into an oven, and drying at 70 ℃ for 12 hours to obtain the three-dimensional framework material.

2. Electronic packaging adhesive

Example 6

1. Three-dimensional framework material

Will be 0.75gPVDF was dissolved in 20ml of acetone, and after stirring for 5min, 0.75g of boron nitride was added thereto, and stirred for 1h to form a boron nitride dispersion. Followed by addition of 3.5g NH ₄ HCO ₃ Stirring for 2 hours, putting into a mould to obtain a required shape, taking out, putting into an oven, and drying at 90 ℃ for 12 hours to obtain the three-dimensional framework material.

2. Electronic packaging adhesive

Example 7

1. Three-dimensional framework material

0.75g PVDF was dissolved in 20ml acetone, and after stirring for 5min, 0.75g boron nitride was added thereto, and stirring was carried out for 1h to form a boron nitride dispersion. Subsequently 3.5g (NH) ₄ ) ₂ CO ₃ Stirring for 2 hours, putting into a mould to obtain a required shape, taking out, putting into a baking oven, and drying at 100 ℃ for 12 hours to obtain the three-dimensional framework material.

2. Electronic packaging adhesive

Example 8

1. Three-dimensional framework material

0.75g of PS was dissolved in 20ml of acetone, and after stirring for 5 minutes, 0.75g of boron nitride was added thereto, and stirring was carried out for 1 hour to form a boron nitride dispersion. Followed by addition of 3.5g NH ₄ HCO ₃ Stirring for 2 hours, putting into a mould to obtain a required shape, taking out, putting into an oven, and drying at 80 ℃ for 12 hours to obtain the three-dimensional framework material.

2. Electronic packaging adhesive

Comparative example 1

Will be 0.75gPVDF was dissolved in 20ml of acetone, and after stirring for 5min, 0.75g of boron nitride was added thereto, and stirred for 1h to form a boron nitride dispersion. Then adding 3.5g NaCl, stirring for 2h, placing into a mould to obtain the required shape, taking out, placing into an oven, drying at 80 ℃ for 12hAnd then putting the mixture into hot water with the temperature of 80 ℃ for repeated washing, and drying until the mass difference between the two times of drying is less than 1 percent.

Comparative example 2

To 20ml of acetone were added 0.75g of PVDF, 0.75g of boron nitride and 3.5g of NH ₄ HCO ₃ Stirring for 2h, putting into a mould to obtain a required shape, taking out, and putting into an oven to dry for 12h at 80 ℃.

Comparative example 3

Uniformly mixing boron nitride powder with PVA at room temperature, wherein the mass fraction of boron nitride is 15%; uniformly mixed PVA and boron nitride powder are pressed into a sheet shape in a tabletting machine under 100MPa for 5min, and a sheet material is obtained; placing the sheet material into a heat treatment chamber at 700 ℃ for 10 hours to decompose PVA, so as to obtain a three-dimensional network skeleton;

placing the three-dimensional network skeleton into a polytetrafluoroethylene mould, filling bisphenol A epoxy resin, and selecting methyl hexahydrophthalic anhydride as a curing agent and imidazole as an accelerator. And (3) placing the electronic packaging adhesive in a vacuum oven to remove bubbles for 0.5h, and then starting to cure, wherein the curing procedures are 70 ℃/2h,110 ℃/2h and 150 ℃/10h, and the electronic packaging adhesive is obtained after curing.

Effect example 1

The electronic packaging adhesives of examples 1 to 8, comparative examples 1 to 3 and the existing product a (CN 111019290B) were tested as follows:

1. thermal conductivity testing: the heat conduction performance of the electronic packaging adhesive is characterized by adopting an LFA447 laser heat conduction instrument of German resistant company.

2. Water absorption test: cutting the electronic packaging adhesive into 10mm is 10mm 4mm, and the mixture is put into an oven at 80 ℃ to be dried for 48 hours, and the original mass W is measured ₀ Immersing in water in a beaker, taking out after seven days, and wiping to obtain the mass W ₁ The water absorption is calculated according to the following formula:

3. coefficient of thermal expansion test: and testing the thermal expansion coefficient of the electronic packaging adhesive by adopting a PCY-1400 thermal expansion coefficient meter of Xiangtan instrument limited company.

4. Resistivity test: and testing the resistivity of the electronic packaging adhesive by adopting an ATI-212 material resistivity tester of Beijing Zhidean Innovative instrument and equipment limited company.

The electronic packaging adhesives of examples 1 to 8, comparative examples 1 to 3 and the conventional product A were tested for their properties according to the test methods described above, and the results are shown in Table 1.

TABLE 1

Note that: in the table, # represents no test.

As can be seen from Table 1, the encapsulation compound prepared in examples 1 to 8 satisfies the high thermal conductivity, low water absorption, low thermal expansion coefficient and high electrical resistivity at the same time. The drying temperatures of example 4 and example 6 were 60℃and 90℃respectively, and the drying temperatures of example 5 and example 1 were 70℃and 80℃respectively, and it is understood from the data in the table that the thermal conductivity of example 5 and example 1 increased significantly from 0.712 to 0.734W/mK to 0.786 to 0.823W/mK when the water absorption, thermal expansion coefficient and electrical resistivity were comparable to those of example 4 and example 6.

In comparative example 1, naCl formed a three-dimensional skeletal material after washing with water, which was different from the pyrolysis material of the present invention, thereby resulting in deterioration of heat conductive property, waterproof property and electrical insulation property.

Comparative example 2 the thermal conductive property of the obtained electronic packaging adhesive was deteriorated by mixing the adhesive, the thermal conductive filler and the pyrolysis material together.

Comparative example 3, which is a compression method commonly used in the prior art to prepare a three-dimensional skeletal material, requires the use of a tablet press and the high pressure of the tablet press as compared to examples 1 to 8 of the present invention. And it is well known in the art that even if the pressure of the tablet press in comparative example 3 is increased, for example to 300MPa, although to some extent an increase in thermal conductivity is favored, there is less impact on the electrical resistivity of the final material. The comparative example 3 has significantly improved thermal conductivity as compared with examples 1 to 8, but has significantly reduced resistivity, which means that the electrical insulation performance of comparative example 3 is poor, the power loss generated during actual use is also greater, more heat is easily generated, and the leakage phenomenon is more easily generated. The electronic packaging adhesive is suitable for precise instruments, not only needs to meet certain heat conduction performance and has higher requirements on insulating performance, but also has higher and better resistivity. Therefore, compared with comparative example 3, the electronic packaging adhesives prepared in examples 1 to 8 of the present application can be better applied in precision instruments.

Compared with the prior product A in the embodiments 1-8, the thermal conductivity of the prior product A is lower, the thermal expansion coefficient is higher, the generated heat can not be transmitted in time in the use process, heat accumulation can be caused, the temperature in the device is rapidly increased, and the operation reliability and the service life of the device are affected.

Effect example 2

The three-dimensional framework materials after drying in examples 1 and 4 to 8 and the electronic packaging adhesive products in examples 1 to 3 and comparative example 2 are placed under a desk-top scanning electron microscope to shoot a scanning electron microscope image.

The coarser part in fig. 1 to 3 is a skeleton structure formed by the heat conductive filler, and the smoother part is a resin material. As can be seen from fig. 1 to 3, the electronic packaging adhesives in embodiments 1 to 3 all obtain compact structures, and the heat conductive filler and the resin material are isolated from each other, so as to form the electronic packaging adhesive with a continuous heat conductive network structure. In the heat transmission process, heat can be directionally transmitted along a network structure formed by the heat conducting filler, so that the heat transmission efficiency is greatly improved, the heat dissipation in the heat transmission process is reduced, and the heat conducting property of the composite material is improved. The dense structures of examples 1-3 can largely avoid the damage of water resistance caused by the entry of moisture into the pores, can prevent the composite material from being affected by external moisture, and avoid the damage of insulation performance caused by the water absorption of the material.

Fig. 4 and fig. 5 are scanning electron microscope images of the electronic packaging adhesive of comparative example 2, and it can be seen from the two images that the electronic packaging adhesive obtained in comparative example 2 has no obvious rough portion and smooth portion, which means that the heat conductive filler and the epoxy resin matrix are not isolated from each other, and cannot form a continuous and compact network skeleton structure, so that the loosening and non-uniformity of the whole three-dimensional skeleton material are caused, and thus the heat conductive property, the waterproof property and the electrical insulation property of the electronic packaging adhesive are not facilitated.

Fig. 6 to 9 are scanning electron microscope images of the three-dimensional framework materials dried in example 4, example 5, example 1 and example 6, respectively. The drying temperatures corresponding to the four examples were 60 ℃, 70 ℃, 80 ℃ and 90 ℃ respectively, and the other steps were the same except for the drying temperatures. From the four graphs, the obtained skeleton material at different drying temperatures has a loose and porous structure, the pore size is between 100 and 300 mu m, and the pore size in the skeleton material slightly increases with the rising of the temperature, but the change is not obvious. When the temperature is 60 ℃, the hole size is between 100 and 200 mu m, and micropores with the size of tens of micrometers are also formed on the wall of the hole structure, so that the uniformity of the internal holes is poor; when the heat drying temperature is between 70 ℃ and 80 ℃, the pore size is between 150 and 200 mu m, and the difference between the heat drying temperature and 60 ℃ is that the number of micro pores of tens of micrometers on the pore wall is obviously reduced. When the temperature reaches 90 ℃, the size of the holes can reach 200-250 mu m, but a small part of holes are adhered, the uniformity of the internal holes is damaged, and the uniformity of the wall thickness of the bracket is also damaged, so that the stability of the three-dimensional framework material structure is not facilitated. Further, the uniformity of the internal holes of the three-dimensional framework material is poor, and certain holes are too large or too small, so that gaps in the electronic packaging adhesive exist or the density of a heat conduction network is too small, and the heat conduction performance of the electronic packaging adhesive is not facilitated.

Fig. 10 and 11 are scanning electron microscope images of the dried skeletal material of examples 7 and 8. From the figure, it can be seen that the two structures form a continuous and compact network framework structure, which is beneficial to the heat conduction performance, the waterproof performance and the electric insulation performance.

Claims

1. The preparation method of the three-dimensional framework material is characterized by comprising the following steps of:

2. The method for preparing a three-dimensional framework material according to claim 1, wherein the adhesive is a thermoplastic resin adhesive;

and/or the heat conductive filler is boron nitride, aluminum oxide, diamond, beryllium oxide, aluminum nitride, silicon carbide, silicon nitride or zinc oxide, preferably boron nitride modified by a fluorine-containing silane coupling agent;

and/or the pyrolyzed material comprises an organic pyrolyzed material comprising polyvinyl alcohol, polypropylene, or polycarbonate;

and/or the pyrolyzing material comprises an inorganic pyrolyzing material comprising NH ₄ HCO ₃ Or (NH) ₄ ) ₂ CO ₃ ；

And/or the molecular particle diameter D90 of the pyrolysis material is 100-500 mu m;

and/or the temperature of the drying is 10-20 ℃ higher than the decomposition temperature of the pyrolysis material.

3. The method for preparing a three-dimensional framework material according to claim 2, wherein the thermoplastic resin adhesive is one or more of polyvinylidene fluoride, polyvinyl acetate, polyacrylate, polystyrene and polysulfone;

and/or the molecular weight of the thermoplastic resin adhesive is 15-70 ten thousand, preferably 57-60 ten thousand;

and/or when the pyrolyzed material is NH ₄ HCO ₃ When the temperature of the drying is 70-80 ℃.

4. A method of producing a three-dimensional skeletal material as defined in any one of claims 1 to 3, wherein the weight ratio of the adhesive to the thermally conductive filler is 1: (0.5 to 2), for example, 1:1 or 1:1.5;

and/or the weight ratio of the adhesive to the pyrolysis material is 1: (2 to 5), for example, 1:2.5 or 1:3, a step of;

and/or the concentration of the adhesive solution is 30-60 g/L, for example 37.5g/L or 50g/L.

5. A three-dimensional skeletal material produced by the method of producing a three-dimensional skeletal material of any one of claims 1 to 4.

6. The preparation method of the electronic packaging adhesive is characterized by comprising the following steps of: immersing the three-dimensional framework material of claim 5 into a resin material and curing.

7. The method of manufacturing an electronic packaging adhesive according to claim 6, wherein the resin material is an epoxy resin material, preferably an epoxy resin E-42;

and/or the resin material further comprises one or more of a toughening agent, a curing agent and a diluent, wherein the diluent is preferably ethylene glycol diglycidyl ether, the toughening agent is preferably YM-004, the curing agent is preferably methylnadic anhydride, and the weight ratio of the epoxy resin E-42, the ethylene glycol diglycidyl ether, the YM-004 and the methylnadic anhydride is preferably 100:20:10:75;

and/or the temperature of the curing is 100-150 ℃, for example 120 ℃;

and/or the curing time is 3 to 10 hours, for example 6 hours;

and/or, before said curing, further comprising evacuating, said evacuating preferably comprising performing a first evacuating, an ultrasonic and a second evacuating in sequence.

8. An electronic packaging paste produced by the method for producing an electronic packaging paste according to claim 6 or 7.

9. The electronic packaging adhesive is characterized by comprising a three-dimensional framework material and a resin material, wherein the three-dimensional framework material comprises an adhesive and a heat-conducting filler;

the resin material is filled in the porous structure of the three-dimensional framework material, and the density of the three-dimensional framework material is 1.4-1.5 g/cm ³ 。

10. Use of an electronic packaging adhesive according to claim 8 or 9 in an electronic component.