CN114426757A - A kind of resin material and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of composite materials, in particular to a high-heat-conductivity high-insulation resin material and a preparation method thereof, wherein the high-heat-conductivity high-insulation resin material comprises 35-50 parts of epoxy resin, 26-40 parts of curing agent, 0.6-1 part of accelerator, 5-20 parts of spherical boron nitride and 5-20 parts of flaky boron nitride, the boron nitride material has excellent insulating property and heat conductivity, two boron nitride fillers with different dimensions can generate synergistic effect, the internal structure of the resin material is designed and adjusted, a heat-conducting network is established, the heat-conducting property of the resin material is improved, and the heat-conducting network can further improve the processing property and the mechanical property of the resin material. The synergistic effect of the two boron nitride fillers can ensure that the performance of the resin material is not deteriorated and improve the heat-conducting property of the resin material, and has wide application prospect.

Description

A kind of resin material and preparation method thereof

technical field

The invention belongs to the technical field of materials, and in particular relates to a resin material and a preparation method thereof.

Background technique

With the development of society and the needs of production, power equipment continues to develop in the direction of high-voltage and large-capacity. The thermal working environment of the switch of the high-voltage power distribution cabinet and the power switch has become a key factor that damages the service life of the equipment. Excellent insulating properties have been widely used in external insulating casting materials. However, the disordered molecular structure of epoxy resin results in low thermal conductivity and limited thermal management capability; in the process of frequent switching of high-voltage equipment, irreversible thermal aging and insulation damage of epoxy resin are caused by heat accumulation. Seriously, it also has a serious impact on the service life of the switchgear.

The existing technology is mainly based on doping modification to improve the thermal conductivity of epoxy resin, introducing ceramic ferroelectric particles and new nanoparticles, alumina, silicon carbide, carbon nanotubes and graphene, etc. The thermal conductivity of resin is limited, and a large amount of filling is required to build an effective thermal conduction path, but a large amount of filling will seriously affect the processing performance of epoxy resin; and this type of filler has excellent thermal conductivity and excellent electrical conductivity. While improving the thermal conductivity of epoxy resin, it will lead to the decrease of the insulating performance of epoxy resin. How to improve the thermal conductivity of epoxy resins without affecting the basic properties of epoxy resins has always been the research focus of those skilled in the art.

SUMMARY OF THE INVENTION

Aiming at the technical problems in the prior art that epoxy resins have poor thermal conductivity, are prone to electrical aging, and conventional thermally conductive modified fillers will change the original properties of epoxy resins, the present invention provides a high thermal conductivity and high insulation resin material and a preparation method thereof. The resin material improves the thermal conductivity of the epoxy resin while ensuring that the mechanical properties and insulating properties of the epoxy resin itself are not deteriorated, the preparation process is simple, and the operation is safe.

In order to achieve the above-mentioned purpose of the invention, the embodiment of the present invention adopts the following technical scheme:

On the one hand, an embodiment of the present invention provides a resin material with high thermal conductivity and high insulation: the raw materials of the material include, in parts by weight, 35 to 50 parts of epoxy resin, 26 to 40 parts of curing agent, and 0.6 to 1 part of accelerator. , 5 to 20 parts of spherical boron nitride, and 5 to 20 parts of flake boron nitride.

Compared with the prior art, the resin material with high thermal conductivity and high insulation provided by the present invention uses epoxy resin as a matrix, and boron nitride with two different dimensions, spherical and flake-like, as fillers. Boron nitride fillers have excellent insulating ability and thermal conductivity. The fillers cooperate with each other to reasonably design and control the internal structure of the resin material to form more thermal conduction paths. These thermal conduction paths can form a dense thermal conduction network inside the resin material, thereby further reducing the phonon scattering rate. In the case of low temperature, the thermal conductivity of epoxy resin is obviously improved.

In addition, spherical boron nitride itself can reduce the viscosity of the resin and optimize the processing performance of the resin; the thermal conductive network formed inside the resin can further ensure the processing performance and mechanical properties of the material; boron nitride can also reduce the freedom of molecular chains in the epoxy resin The volume of the epoxy resin chain restricts the movement of segments, thereby improving the thermal stability and aging resistance of the epoxy resin. In short, the synergistic effect of spherical boron nitride and flake boron nitride can significantly improve the thermal conductivity and insulating properties of the resin material with a small amount of filling, and ensure or even improve the thermal stability and processing performance of the resin material. .

Preferably, the mass ratio of spherical boron nitride and flake boron nitride is 1:0.9-1.1.

The mass ratio of spherical boron nitride and flake boron nitride is related to the construction efficiency of the internal thermal network of the resin material. Under the preferred ratio, the formation efficiency and effect of the thermal conduction path inside the resin is the best, and the filler can be further reduced while achieving the same performance. doping ratio.

Preferably, the particle size of spherical boron nitride is 50-100 μm, the particle size of flake boron nitride is 10-30 μm, and the aspect ratio is ≥100.

The selection of boron nitride materials with specific particle size and specific aspect ratio can give full play to the synergistic effect of spherical boron nitride and flake boron nitride, and further reduce the doping ratio of fillers while achieving the same effect.

Preferably, the epoxy resin is one of bisphenol A epoxy resin E51 and bisphenol A epoxy resin E44.

The preferred epoxy resin has outstanding mechanical strength, and has certain aging resistance and insulating properties, which can provide a good foundation for the mechanical strength, thermal stability and insulating properties of the final resin material.

Preferably, the curing agent is a polyamide 650 curing agent, and the accelerator is a DMP-30 accelerator.

On the other hand, the present invention also provides a preparation method of the high thermal conductivity and high insulation resin material, the method specifically comprises the following steps:

S1: prepare the raw material of the high thermal conductivity and high insulation resin material and 0.8-1.5 parts of the regulating liquid according to the formula amount, and premix the epoxy resin, the curing agent and the accelerator to obtain a resin matrix;

S2: Add spherical boron nitride and flaky boron nitride into the resin matrix obtained from S1 under stirring, continue stirring to make spherical boron nitride and flaky boron nitride evenly dispersed in the resin matrix, add regulating liquid and stir After dispersion, a resin material with high thermal conductivity and high insulation to be cured is obtained;

S3: curing the high thermal conductivity and high insulation resin material obtained in S2 to obtain the high thermal conductivity and high insulation resin material.

Compared with the prior art, in the preparation method of the resin material with high thermal conductivity and high insulation provided by the present invention, a regulating liquid is added in the preparation process, and the regulating liquid can control the distribution state of spherical boron nitride and flake boron nitride filler in the resin. Adjustment and optimization can improve the distribution effect of the filler, which is more conducive to the construction of the internal thermal network of the material; the specific order of adding the raw materials and the mixing method can help to mix the components evenly and ensure the stability of the material properties. The whole preparation process is simple, easy to operate, safe and pollution-free.

Preferably, the regulating liquid is one of acetone and absolute ethanol.

The optimal control solution can control the distribution state of spherical boron nitride and flake boron nitride in epoxy resin, improve the thermal conductivity network formed inside epoxy resin, further improve the thermal conductivity of epoxy resin, and also improve the thermal conductivity of resin. Thermal stability properties.

Preferably, the stirring speed during and after the addition of spherical boron nitride in S2 is 300-500 r/min, and the time is 0.8-1.5 h.

Preferably, the curing process of the high thermal conductivity and high insulating resin material is carried out in a vacuum environment, and the specific method is as follows: heating to 60-80°C in a vacuum environment, keeping the temperature at 20-30°C and then placing it in an environment of 100-120°C, keeping the temperature at 100-120°C. After 5-7 hours, the temperature is lowered to room temperature to obtain the high thermal conductivity and high insulation resin material.

Description of drawings

FIG. 1 is a physical diagram of Example 1 and Comparative Example 1 of the present invention.

2 is a comparison diagram of the thermal conductivity of the resin materials prepared in Example 1 of the present invention and Comparative Examples 1-3.

3 is a comparison diagram of the DSC thermomechanical stability of the resin materials prepared in Example 1 and Comparative Examples 1-3.

4 is a comparison diagram of the insulating properties of the resin materials prepared in Example 1 and Comparative Examples 1-3.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

Epoxy resin has excellent insulating properties and has been widely used in external insulating casting materials. With the continuous development of power equipment in the direction of high-voltage and large-capacity, the thermal working environment of the switch of the high-voltage power distribution cabinet and the power switch has become a key factor that damages the service life of the equipment. The defects of low conductivity and limited thermal management ability; gradually unable to meet this development trend, especially in the process of frequent switching of high-voltage equipment, due to the accumulation of heat, the irreversible thermal aging and insulation damage of epoxy resin continue to increase. The service life of the switchgear also has a serious impact.

Introducing ceramic ferroelectric particles and new nanoparticles into epoxy resins, and doping and modifying epoxy resins with materials such as alumina, silicon carbide, carbon nanotubes and graphene is the most common way in this field. The thermal conductivity of epoxy resin is limited, and a large amount of filling is required to build an effective thermal conduction path. A large amount of filling will seriously affect the processing performance of epoxy resin; and this type of filler improves the thermal conductivity of epoxy resin. Decreased insulation properties of oxy-resin. How to improve the thermal conductivity of epoxy resins without affecting the basic properties of epoxy resins has always been the research focus of those skilled in the art.

In order to solve the technical problem that conventional thermally conductive modified fillers will change the original properties of epoxy resins, and to improve the thermal conductivity of epoxy resins while ensuring that the mechanical properties and insulating properties of epoxy resins themselves do not deteriorate, the present invention provides a High thermal conductivity and high insulation resin material, the raw materials of this material are calculated in parts by weight, including 35-50 parts of epoxy resin, 26-40 parts of curing agent, 0.6-1 part of accelerator, 5-20 parts of spherical boron nitride, sheet 5 to 20 parts of boron nitride. The resin material with high thermal conductivity and high insulation is based on epoxy resin, and boron nitride with two different dimensions of spherical and flakes is used as filler. Boron nitride fillers have excellent insulating ability and thermal conductivity. The fillers cooperate with each other to reasonably design and control the internal structure of the resin material to form more thermal conduction paths. These thermal conduction paths can form a dense thermal conduction network inside the resin material, thereby further reducing the phonon scattering rate. In the case of low temperature, the thermal conductivity of epoxy resin is obviously improved. And spherical boron nitride itself can reduce the viscosity of the resin and optimize the processing performance of the resin; the thermal conductive network formed inside the resin can further ensure the processing performance and mechanical properties of the material; boron nitride can also reduce the free volume of the molecular chain in the epoxy resin , limiting the segmental movement of the epoxy resin chain, thereby improving the thermal stability and aging resistance of the epoxy resin. In short, the synergistic effect of spherical boron nitride and flake boron nitride can significantly improve the thermal conductivity and insulating properties of the resin material with a small amount of filling, and ensure or even improve the thermal stability and processing performance of the resin material. .

In the research, the inventor found that the mass ratio of spherical boron nitride and flake boron nitride is the best for the construction efficiency of the thermal conduction network inside the resin material, and the formation efficiency and effect of the thermal conduction path inside the resin are the best, and can further reduce the performance while achieving the same performance. The doping ratio of the filler, the mass ratio of spherical boron nitride and flake boron nitride in the examples of the present application is 1:0.9-1.1.

In order to give full play to the synergistic effect of spherical boron nitride and flake boron nitride, and to further reduce the doping ratio of fillers while achieving the same effect, the particle size of spherical boron nitride in the examples of the present application is 50-100 μm, The particle size of the flake boron nitride is 10-30 μm, and the aspect ratio is greater than or equal to 100.

The present invention also provides a preparation method of the high thermal conductivity and high insulation resin material, which specifically comprises the following steps:

S1: prepare the raw material of the high thermal conductivity and high insulation resin material and 0.8-1.5 parts of the regulating liquid according to the formula amount, and premix the epoxy resin, the curing agent and the accelerator to obtain a resin matrix;

S2: Add spherical boron nitride and flaky boron nitride into the resin matrix obtained from S1 under stirring, continue stirring to make spherical boron nitride and flaky boron nitride evenly dispersed in the resin matrix, add regulating liquid and stir After dispersion, a resin material with high thermal conductivity and high insulation to be cured is obtained;

S3: curing the high thermal conductivity and high insulation resin material obtained in S2 to obtain the high thermal conductivity and high insulation resin material.

Adding a regulating liquid during the preparation of high thermal conductivity and high insulating resin materials can adjust and optimize the distribution state of spherical boron nitride and flake boron nitride fillers in the resin, improve the distribution effect of the fillers, and help the interior of the material. The construction of the heat conduction network; the specific order of adding the raw materials and the mixing method help to mix the components evenly and ensure the stability of the properties of the material. The whole preparation process is simple, easy to operate, safe and pollution-free.

In order to control the distribution state of spherical boron nitride and flake boron nitride in epoxy resin, improve the thermal conductivity network formed inside epoxy resin, further improve the thermal conductivity of epoxy resin and improve the thermal stability of resin, After further exploration by the inventor, the preferred regulating solution is one of acetone and absolute ethanol.

The present invention will be further described below by dividing into multiple embodiments.

In the following examples, the curing agent and accelerator are polyamide 650 curing agent and DMP-30 accelerator.

Example 1

This embodiment provides a resin material with high thermal conductivity and high insulation. The raw materials, in parts by mass, include bisphenol A epoxy resin E44: 38.5 parts, curing agent 30.5 parts, accelerator 1 part, spherical boron nitride 15 parts and 15 parts of flake boron nitride, wherein the particle size of spherical boron nitride is 50-100 μm, and the aspect ratio of flake boron nitride is ≥100;

The preparation method of the high thermal conductivity and high insulation resin material specifically includes the following steps:

S1: Weigh each raw material and 0.9 part of acetone regulating solution according to the formula, mix the epoxy resin, curing agent and accelerator, and premix in a stirring device to obtain a resin matrix;

S2: In the state of stirring, insert spherical boron nitride and flake boron nitride into the resin matrix obtained from S1, and stir at a speed of 300r/min for 1 h to make spherical boron nitride and flake boron nitride in the resin The matrix is uniformly dispersed; after adding the regulating liquid, continue to stir for 2 minutes to obtain the resin material with high thermal conductivity and high insulation to be cured;

S3: The resin material with high thermal conductivity and high insulation to be cured obtained in S2 is heated to 70°C in a vacuum environment, kept at 100°C for 5 hours after being kept for 20 minutes, and the resin material with high thermal conductivity and high insulation is obtained after cooling to room temperature. .

Example 2

This embodiment provides a resin material with high thermal conductivity and high insulation. The raw materials, in parts by mass, include bisphenol A epoxy resin E51: 50 parts, curing agent 40 parts, accelerator 1 part, spherical boron nitride 20 parts and 20 parts of flake boron nitride, wherein the particle size of spherical boron nitride is 50-100 μm, and the aspect ratio of flake boron nitride is ≥100;

The preparation method of the high thermal conductivity and high insulation resin material specifically includes the following steps:

S1: Weigh each raw material and 1.5 parts of anhydrous ethanol control solution according to the formula, mix the epoxy resin, the curing agent and the accelerator, and premix them in a stirring device to obtain a resin matrix;

S2: In the state of stirring, insert spherical boron nitride and flake boron nitride into the resin matrix obtained from S1, and stir at a speed of 500r/min for 1.5h to make spherical boron nitride and flake boron nitride in The resin matrix is uniformly dispersed; after adding the regulating liquid, continue stirring for 2 minutes to obtain the resin material with high thermal conductivity and high insulation to be cured;

S3: Heat the resin material with high thermal conductivity and high insulation obtained in S2 to 80°C in a vacuum environment, keep it in a 120°C environment for 7 hours, and then cool it down to room temperature to obtain the high thermal conductivity and high insulation resin material .

Comparative Example 1

This comparative example provides a resin material, and its raw materials, in terms of mass fraction, include bisphenol A epoxy resin E44: 38.5 parts, 30.5 parts of curing agent and 1 part of accelerator;

The preparation method of this resin material specifically comprises the following steps:

S1: Weigh the raw materials according to the formula, mix the epoxy resin, the curing agent and the accelerator, and stir in a stirring device at a speed of 300 r/min for 1 hour to obtain the resin to be cured after premixing;

S2: The resin to be cured obtained in S1 is heated to 70° C. in a vacuum environment, kept at 100° C. for 20 minutes, and then placed in an environment of 100° C. for 5 hours, and the resin material is obtained after cooling to room temperature.

Comparative Example 2

This comparative example provides a resin material whose raw materials, in parts by mass, include bisphenol A epoxy resin E44: 38.5 parts, curing agent 30.5 parts, accelerator 1 part and spherical boron nitride 30 parts, of which spherical nitrogen The particle size of boronide is 50～100μm;

The preparation method of the high thermal conductivity and high insulation resin material specifically includes the following steps:

S1: Weigh the raw materials according to the formula, mix the epoxy resin, the curing agent and the accelerator, and premix them in a stirring device to obtain a resin matrix;

S2: adding spherical boron nitride into the resin matrix obtained from S1 under stirring, and stirring for 1 h at a rotational speed of 300 r/min so that the spherical boron nitride is uniformly dispersed in the resin matrix to obtain the resin material to be cured;

S3: The resin material to be cured obtained in S2 is heated to 70° C. in a vacuum environment, kept at 100° C. for 20 minutes, and then kept in an environment of 100° C. for 5 hours, and the resin material is obtained after cooling to room temperature.

Comparative Example 3

This comparative example provides a resin material, the raw materials of which, in parts by mass, include bisphenol A epoxy resin E44: 38.5 parts, curing agent 30.5 parts, accelerator 1 part and flaky boron nitride 30 parts, of which the flakes The aspect ratio of boron nitride is greater than or equal to 100;

The preparation method of the high thermal conductivity and high insulation resin material specifically includes the following steps:

S1: Weigh the raw materials according to the formula, mix the epoxy resin, the curing agent and the accelerator, and premix them in a stirring device to obtain a resin matrix;

S2: in the state of stirring, add the flake boron nitride to the resin matrix obtained from S1, and stir at a speed of 300 r/min for 1 h so that the flake boron nitride is uniformly dispersed in the resin matrix to obtain the resin material to be cured;

S3: The resin material to be cured obtained in S2 is heated to 70° C. in a vacuum environment, kept at 100° C. for 20 minutes, and then kept in an environment of 100° C. for 5 hours, and the resin material is obtained after cooling to room temperature.

Detection example

Detect the appearance and performance of the resin materials prepared in Examples 1, 2 and Comparative Examples 1 to 3, and the specific detection methods and detection results are as follows:

(1) Appearance:

The actual pictures of the resin materials prepared in Example 1 of the present invention and Comparative Example 1 are shown in Figure 1 . The left side of Figure 1 is the resin material prepared in Example 1 of the present invention, and the right side of Figure 1 is the resin material prepared by Comparative Example 1 of the present invention

(2) Thermal conductivity:

The thermal conductivity of the resin material was tested by the heat flow method, and the test results are shown in Figure 2:

The thermal conductivity of the resin materials obtained in Example 1 and Example 2 are similar, and only the test results of Example 1 are shown in FIG. 2 .

It can be seen from FIG. 2 that the thermal conductivity of Example 1 is significantly improved compared to the comparative examples. Under the same doping ratio, the thermal conductivity network is efficiently constructed through the preferred ratio, and its thermal conductivity is higher than that of the single doped sample (Comparative Example 2, Comparative Example 3) without considering the thermal conductivity network construction efficiency. 51.45%, 34.43%. It can be seen that the design of the internal thermal conduction path of the resin material by using boron nitride fillers of different dimensions can minimize the level of phonon scattering, thereby significantly improving the thermal conductivity of the resin material.

(3) Mechanical properties and thermal stability:

The temperature-storage modulus curve of the resin material is tested, and the test results are shown in Figure 3:

The thermal conductivity of the resin materials obtained in Example 1 and Example 2 are similar, and only the test results of Example 1 are shown in FIG. 3 .

It can be seen from FIG. 3 that compared with Comparative Examples 1 to 3, the storage modulus of Example 1 is the highest, which indicates that the mechanical strength of the resin material prepared in Example 1 is more prominent; and the thermal failure of Example 1 The temperature is also significantly higher than that of the comparative examples, which also shows that the resin material prepared in Example 1 has better thermal stability and mechanical strength.

(4) Resistivity

The resistivity of the resin material was tested with a high resistance meter, and the test results are shown in Figure 4.

The resistivity of the resin materials obtained in Example 1 and Example 2 are similar, and only the detection result of Example 1 is shown in FIG. 4 .

It can be seen from Figure 4 that after doping the filler, the resistivity of the resin materials obtained in Example 1, Comparative Example 2, and Comparative Example 3 are all better than those in Comparative Example 1. It can be seen that the filling of boron nitride filler can improve the epoxy resin's resistivity. insulation level.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. a resin material, it is characterized in that, its raw material by weight, comprises epoxy resin 35～50 parts, curing agent 26～40 parts, accelerator 0.6～1 part, spherical boron nitride 5～20 parts and 5 to 20 parts of flaky boron nitride. 2 . The resin material according to claim 1 , wherein the mass ratio of the spherical boron nitride and the flake boron nitride is 1:0.9˜1.1. 3 . 3 . The resin material according to claim 1 , wherein the spherical boron nitride has a particle size of 50 to 100 μm. 4 . 4 . The resin material according to claim 1 , wherein the particle size of the flake boron nitride is 10-30 μm, and the aspect ratio is greater than or equal to 100. 5 . 5 . The resin material according to claim 1 , wherein the epoxy resin is bisphenol A epoxy resin E51 or bisphenol A epoxy resin E44. 6 . 6. The resin material according to claim 1, wherein the curing agent is a polyamide 650 curing agent, and the accelerator is a DMP-30 accelerator. 7. a preparation method of resin material, is characterized in that, specifically comprises the following steps: S1: prepare each raw material and 0.8-1.5 parts of regulating liquid according to the formulation amount of the resin material described in any one of claims 1-6, and obtain a resin matrix after premixing the epoxy resin, the curing agent and the accelerator; S2: adding spherical boron nitride and flaky boron nitride into the resin matrix under stirring, and continuing to stir so that the spherical boron nitride and flaky boron nitride are uniformly dispersed in the resin matrix; adding After the control liquid is stirred and dispersed, the resin material to be cured is obtained; S3: the resin material to be cured is cured to obtain the resin material. 8. The preparation method of resin material as claimed in claim 7, is characterized in that, described regulation liquid is acetone or absolute ethanol. 9 . The preparation method of resin material according to claim 7 , wherein the spherical boron nitride and flake boron nitride in S2 are added at a stirring speed of 300-500 r/min and a time of 0.8-1.5 h. 10 . . 10 . The preparation method of resin material according to claim 7 , wherein the curing process of the resin material in S3 is carried out in a vacuum environment, and the specific method is, heating to 60-80° C. in a vacuum environment, and keeping the temperature in the vacuum environment. 11 . After 20-30 minutes, the resin material is obtained by placing it in an environment of 100-120° C., keeping the temperature for 5-7 hours and then lowering to room temperature.

Images