CN114605706B

CN114605706B - Heat-conducting powder and preparation method thereof

Info

Publication number: CN114605706B
Application number: CN202210261831.9A
Authority: CN
Inventors: 邓娇容; 甘祖荣; 常红丽
Original assignee: Shenzhen Jinhaohui Industrial Development Co ltd
Current assignee: Shenzhen Jinhaohui Industrial Development Co ltd
Priority date: 2022-03-16
Filing date: 2022-03-16
Publication date: 2023-11-10
Anticipated expiration: 2042-03-16
Also published as: CN114605706A

Abstract

The application provides heat-conducting powder and a preparation method thereof, wherein the heat-conducting powder comprises the following raw materials in parts by weight: a complex: 15-25 parts of a composite, wherein the composite comprises silicon dioxide and aluminum oxide; calcium oxide: 5-12 parts; silane coupling agent: 1 to 5 parts. In the application, the silicon dioxide and the aluminum oxide are compounded, and then the compound is compounded with the calcium oxide and the silane coupling agent, so that the heat conduction performance is good, and the compound can be fully dispersed in an organic resin system when in use. Because the silicon dioxide and the aluminum oxide of the internal system are tightly combined, the heat conductivity is improved, and the surface system is modified by the silane coupling agent, so that the dispersibility in an organic resin system is ensured.

Description

Heat-conducting powder and preparation method thereof

Technical Field

The application belongs to the field of materials, and particularly relates to heat conduction powder and a preparation method thereof.

Background

The electronic device emits heat during use, and therefore, a heat conductive material is required to be installed between the components, and the heat generated during use is emitted. However, a heat conductive material such as a metal is difficult to form close contact with a member due to molding, and thus the heat conductive property is deteriorated, and the application thereof is limited. In order to overcome the defect, the prior art is to compound various heat conduction materials with high polymer materials such as resin, and the like, so that the heat conduction is realized on the premise of meeting the tightness.

The inorganic heat conducting material is modified and then mixed with the resin material to form a mode of improving the doping proportion of the heat conducting material, so that the heat conductivity of the composite material is improved.

However, since the modifier is mixed between the heat conductive material and the heat conductive material, the heat conductivity of the heat conductive material itself becomes poor, and the heat conductive efficiency is lowered, so that the heat conductive performance cannot be fully exerted, and the application of the heat conductive material is limited.

Disclosure of Invention

The application provides heat conduction powder and a preparation method thereof, and aims to provide powder which can further improve the heat conduction performance of organic resin while forming a good compound system.

In order to achieve the above purpose, the application provides a heat conduction powder, which comprises the following raw materials in parts by weight:

a complex: 15-25 parts of a compound, wherein the compound is obtained by in-situ bonding of alumina on the surface of silicon dioxide;

calcium oxide: 5-12 parts; the method comprises the steps of,

silane coupling agent: 1 to 5 parts.

Optionally, the D50 of the thermally conductive powder is 4 μm to 8 μm.

Optionally, the silane coupling agent comprises at least one of silane coupling agent KH-551 and gamma-aminopropyl triethoxysilane.

Optionally, the heat-conducting powder comprises the following raw materials in parts by weight:

a complex: 20-22 parts;

calcium oxide: 8-10 parts;

silane coupling agent KH-551:1 to 2 parts; the method comprises the steps of,

gamma-aminopropyl triethoxysilane: 1 to 3 parts.

In addition, the application also provides a preparation method of the heat-conducting powder, which comprises the following steps:

mixing hydrophilic silicon dioxide and alumina gel to obtain a compound precursor;

calcining the compound precursor to obtain the compound;

the silane coupling agent is adopted to carry out hydrophobic modification on the compound and calcium oxide respectively;

and mixing the modified compound and the modified calcium oxide to obtain the heat conducting powder.

Optionally, the step of mixing hydrophilic silica with alumina gel to obtain a composite precursor comprises:

dispersing hydrophilic silicon dioxide in a solution containing an aluminum source to obtain a first mixture;

adding a hydrolyzer into the first mixture, and hydrolyzing the aluminum source into sol to obtain a second mixture;

and gelling the second mixture, drying and calcining to obtain the compound precursor.

Optionally, in the step of dispersing the hydrophilic silica in a solution containing an aluminum source to obtain the first mixture, the molar ratio of silicon element to aluminum element is 1: (0.8-1); and/or the number of the groups of groups,

the aluminum source includes at least one of aluminum trichloride and aluminum nitrate.

Optionally, in the step of adding a hydrolyzer to the first mixture to hydrolyze the aluminum source into a sol and obtain a second mixture, the hydrolyzer includes at least one of ammonia water and anhydrous sodium acetate; and/or the number of the groups of groups,

the hydrolytic agent is added into the first mixture until the pH value is 4-6; and/or the number of the groups of groups,

the hydrolysis is carried out at 70-85 ℃ for 1.5-3 hours.

Optionally, the step of aging the second mixture, drying and calcining to obtain the composite precursor includes:

the aging time of the second mixture is 70-100 ℃; and/or the number of the groups of groups,

the calcining temperature is 800-1100 ℃; and/or the number of the groups of groups,

the calcination time is 4-6 hours.

In addition, the application also provides a heat-conducting packaging composite material, which comprises resin and the heat-conducting powder.

In the application, the silicon dioxide and the aluminum oxide are compounded, and then the compound is compounded with the calcium oxide and the silane coupling agent, so that the heat conduction performance is good, and the compound can be fully dispersed in an organic resin system when in use. Because the silicon dioxide and the aluminum oxide of the internal system are tightly combined, the heat conductivity is improved, and the surface system is modified by the silane coupling agent, so that the dispersibility in an organic resin system is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of the production of the heat conductive powder of the present application;

the achievement of the objects, functional features and advantages of the present application will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below. It will be apparent that the described embodiments are only some, but not all, embodiments of the application.

The specific conditions were not specified in the examples, and the examples were conducted under the conventional conditions or the conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be regarded as not exist and not within the protection scope of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

In view of the technical defect that the doping amount of the heat conducting powder is increased but the heat conducting property is reduced due to the addition of the modifier in the prior heat conducting powder in the background art. The application provides heat-conducting powder which comprises the following raw materials in parts by weight:

calcium oxide: 5-12 parts; the method comprises the steps of,

silane coupling agent: 1 to 5 parts.

In some embodiments, the thermally conductive powder has a D50 of 4 μm to 8 μm.

By controlling the particle size in the above range, the heat conductive powder and the organic resin system can be compounded more easily, and the doping amount is increased.

In some embodiments, the silane coupling agent includes at least one of a silane coupling agent KH-551 and gamma-aminopropyl triethoxysilane.

By selecting the silane coupling agent, the surface of the complexing agent and the surface of the calcium oxide can be effectively modified, and the doping amount in the organic resin system can be increased.

In some embodiments, the thermally conductive powder comprises the following raw materials in parts by weight:

a complex: 20-22 parts;

calcium oxide: 8-10 parts;

silane coupling agent KH-551:1 to 2 parts; the method comprises the steps of,

gamma-aminopropyl triethoxysilane: 1 to 3 parts.

By controlling the raw materials in the above range, the compatibility with the organic resin can be further improved and the thermal conductivity of the thermal conductive powder can be enhanced.

step S10: mixing hydrophilic silicon dioxide and alumina gel to obtain a compound precursor;

step S20: calcining the compound precursor to obtain the compound;

step S30: the silane coupling agent is adopted to carry out hydrophobic modification on the compound and calcium oxide respectively;

step S40: and mixing the modified compound and the modified calcium oxide to obtain the heat conducting powder.

By adopting the steps, a powder system with good compatibility with an organic resin system and good thermal conductivity can be prepared.

Step S10:

step S101: dispersing hydrophilic silicon dioxide in a solution containing an aluminum source to obtain a first mixture;

step S102: adding a hydrolyzer into the first mixture, and hydrolyzing the aluminum source into sol to obtain a second mixture;

step S103: and aging the second mixture, drying and calcining to obtain the compound precursor.

By the steps, a closely contacted silica and alumina system can be prepared, thereby improving the thermal conductivity of the powder.

In some embodiments, in step S101, the molar ratio of elemental silicon to elemental aluminum is 1: (0.8-1). When the ratio of the silicon element to the aluminum element is controlled within this range, it is advantageous to further increase the thermal conductivity of the powder.

In the present application, the aluminum source may be a substance that undergoes a hydrolysis reaction with an alkaline substance, and may include at least one of aluminum trichloride and aluminum nitrate, provided that the substance is a substance that undergoes a hydrolysis reaction with an alkaline substance.

In the step S102, the hydrolysis agent is an alkaline substance capable of performing a hydrolysis reaction on an aluminum source, and on the premise that the hydrolysis agent includes at least one of ammonia water and anhydrous sodium acetate.

In some embodiments, the hydrolyzing agent is added to the first mixture until the pH is 4 to 6; the hydrolysis is carried out at 70-85 ℃ for 1.5-3 hours.

The pH, hydrolysis temperature and time of the hydrolysis are controlled in the above ranges, and the size of the alumina particle size can be controlled to form a composite system with the silicon dioxide, and meanwhile, the aluminum source is completely hydrolyzed.

Step S20 includes:

the ageing temperature of the second mixture is 70-100 ℃; the calcining temperature is 800-1100 ℃; the calcination time is 4-6 hours. The formation of a gelled system can be ensured by controlling the ageing temperature to 70-100 ℃. The calcination temperature is controlled at 800-1100 ℃ and the calcination time is 4-6 hours, so that the alumina gel can be further completely converted and a system closely contacted with the silicon dioxide can be formed.

Step S30 includes:

step S301: the composite is modified with gamma-aminopropyl triethoxysilane.

Step S302: and modifying the calcium oxide by adopting a silane coupling agent KH-551.

The composite and the calcium oxide are modified respectively, so that the reaction of the calcium oxide and the adsorbed moisture of the composite is avoided, and the reduction of the thermal conductivity is caused. Meanwhile, the research team of the application discovers that the thermal conductivity of the composite is further improved when the composite is modified by adopting gamma-aminopropyl triethoxysilane and the calcium oxide is modified by adopting a silane coupling agent KH-551.

In addition, the application also provides a heat-conducting packaging composite material, which comprises resin and the heat-conducting powder. The heat conducting powder is modified to have hydrophobicity and can be compounded with a resin system to form the resin system with heat conducting property.

The following technical solutions of the present application will be described in further detail with reference to specific examples and drawings, and it should be understood that the following examples are only for explaining the present application and are not intended to limit the present application.

Examples 1 to 6

Examples 1 to 6 each provide a heat conductive powder, and specific components, parts by weight and particle diameters thereof are shown in table 1.

Table 1 examples 1 to 6 parameters of thermally conductive powders

Examples 1 to 6 also provide a process for the preparation of the above powder, comprising the specific steps of:

step S101: dispersing hydrophilic silica (available from An Bi, model DNG-B017) in a solution containing an aluminum source to obtain a first mixture;

step S102: adding ammonia water into the first mixture, and hydrolyzing an aluminum source into sol to obtain a second mixture;

step S103: the second mixture was aged and then dried at 110 ℃ for 12 hours to give a composite precursor.

Step S20: calcining the compound precursor to obtain a compound;

step S301: and soaking the compound in a silane coupling agent for 6 hours, and drying to obtain the modified compound.

Step S302: and (3) immersing the calcium oxide in a silane coupling agent for 6 hours, and drying to obtain the modified calcium oxide.

Step S40: and mixing the modified compound and the modified calcium oxide, grinding and sieving to obtain the heat-conducting powder with the required particle size. The reaction parameters of examples 1 to 6 are shown in Table 2.

TABLE 2 reaction parameters for examples 1-6

Comparative example 1

Comparative example 1 provides a heat conductive powder having the same raw material composition and preparation method as in example 3, except that calcium oxide was replaced with zinc oxide.

Comparative example 2

Comparative example 2 provides a heat conductive powder, which comprises the following components in parts by weight:

hydrophilic silica: 8.47 parts of nano aluminum oxide: 11.52 parts of calcium oxide: 8 parts of silane coupling agent KH-551:1 part of gamma-aminopropyl triethoxysilane: 3 parts.

Comparative example 2 also provides a process for the preparation of the above powder, comprising in particular the following steps:

step S1: and mixing hydrophilic silicon dioxide and nano aluminum oxide to obtain a compound, then mixing the compound with gamma-aminopropyl triethoxysilane, standing for 6 hours, and drying to obtain the modified compound.

Step S2: mixing the calcium oxide with a silane coupling agent KH-551, standing for 6 hours, and drying to obtain the modified calcium oxide.

Step S3: and mixing the modified compound and the modified calcium oxide, and grinding to obtain the heat-conducting powder with the particle size D50 of 5 mu m after sieving.

Application examples

In this embodiment, the heat conductive powders of examples 1 to 6 and comparative examples 1 to 2 are prepared into a heat conductive packaging material, and the specific preparation method is as follows:

mixing 35 parts by weight of heat conduction powder with 0.4 part by weight of N-methylpyrrolidone, 0.8 part by weight of pyridine and 0.15 part by weight of triphenyl phosphite for reaction for 3 hours, adding lithium chloride and methanol for reaction for 40 minutes, filtering, flushing with N, N-dimethylformamide, then placing into a vacuum drying oven for drying at the temperature of 90 ℃, adding acetone, and performing ultrasonic dispersion for 40 minutes; mixing 50 parts by weight of bisphenol A epoxy resin, 3 parts by weight of neodymium acetylacetonate and water, heating to 85 ℃, stirring and dissolving; mixing the two mixtures, stirring at 500r/min by using a stirrer while carrying out ultrasonic treatment for 25 minutes, placing in a water bath at 70 ℃, adding 2 parts by weight of 3, 5-diaminobenzoic acid, 0.8 part by weight of N-aminoethylpiperazine and 2 parts by weight of trimethyl hexamethylenediamine, stirring for 7.5 minutes by using the stirrer, vacuum degassing for 25 minutes, finally pouring the mixture into a mould, pre-curing at 135 ℃ for 2.5 hours, heating to 165 ℃ and curing for 14 hours, and cooling to obtain the modified polyurethane foam.

Test example:

the thermal conductivity of the heat conductive powders produced in examples 1 to 6 and comparative examples 1 to 2 was measured by the transient hot wire method, the measurement results are shown in table 3, and the thermal conductivity of the heat conductive sealing materials prepared in examples 1 to 6 and comparative examples 1 to 2 was measured by ASTM D5470, and the measurement results are shown in table 4.

TABLE 3 thermal conductivity of the thermally conductive powders produced in examples 1 to 6 and comparative examples 1 to 2

Examples	Thermal conductivity (W/mk)
		Example 1	0.061
Example 2	0.062
		Example 3	0.061
Example 4	0.063
		Example 5	0.064
Example 6	0.058
		Comparative example 1	0.039
Comparative example 2	0.042

As can be seen from table 3, compared with comparative example 1, the heat conductive powder of the present application added with calcium oxide, compared with comparative example 2, the present application adopts in situ generation of nano alumina on hydrophilic silica, and its heat conductive property reaches more than 0.055W/mk;

meanwhile, the research team of the application discovers that the application adopts the gamma-aminopropyl triethoxysilane modified composite material, the silane coupling agent KH-551 modifies the calcium oxide, and the thermal conductivity of the calcium oxide reaches more than 0.06W/mk.

Table 4 thermal conductivity of thermally conductive packaging materials prepared from thermally conductive powders of examples 1 to 2 and comparative examples 1 to 2

Examples	Thermal conductivity (W/mk)
		Example 1	0.045
Example 2	0.046
		Example 3	0.047
Example 4	0.046
		Implementation of the embodimentsExample 5	0.048
Example 6	0.042
		Comparative example 1	0.039
Comparative example 2	0.035

As can be seen from Table 4, compared with comparative examples 1-2, the heat conductive powder of the present application can achieve a heat conductivity of 0.04W/mk or more while being incorporated into a resin system in a large proportion, and the heat conductive powder of calcium oxide is further improved to 0.045W/mk by using the gamma-aminopropyl triethoxysilane modified composite material and the silane coupling agent KH-551.

The foregoing is merely a preferred embodiment of the present application and is not intended to limit the scope of the present application, but various modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. The preparation method of the heat-conducting powder is characterized by comprising the following raw materials in parts by weight:

a complex: 20-22 parts of a compound, wherein the compound is obtained by in-situ bonding of alumina on the surface of silicon dioxide;

calcium oxide: 8-10 parts of a rubber bag;

silane coupling agent KH-551: 1-2 parts of a rubber; the method comprises the steps of,

gamma-aminopropyl triethoxysilane: 1-3 parts of a rubber composition;

the preparation method of the heat conduction powder comprises the following steps:

calcining the compound precursor to obtain the compound;

mixing the modified compound with the modified calcium oxide to obtain the heat-conducting powder;

wherein, the step of mixing hydrophilic silica with alumina gel to obtain a composite precursor comprises:

and aging the second mixture, drying and calcining to obtain the compound precursor.

2. The method of preparing a thermally conductive powder of claim 1, wherein the thermally conductive powder has a D50 of 4 μm to 8 μm.

3. The method of preparing a heat conductive powder according to claim 1, wherein in the step of dispersing hydrophilic silica in a solution containing an aluminum source to obtain a first mixture, a molar ratio of silicon element to aluminum element is 1: (0.8-1); and/or the number of the groups of groups,

4. The method of producing a heat conductive powder according to claim 1, wherein in the step of adding a hydrolyzer to the first mixture to hydrolyze the aluminum source to a sol and to obtain a second mixture, the hydrolyzer comprises at least one of ammonia water and anhydrous sodium acetate; and/or the number of the groups of groups,

the hydrolysis is carried out for 1.5 to 3 hours at the temperature of 70 to 85 ℃.

5. The method of preparing a thermally conductive powder of claim 1, wherein the step of aging the second mixture, drying and calcining to obtain the composite precursor comprises:

the aging temperature of the second mixture is 70-100 ℃; and/or the number of the groups of groups,

the calcination time is 4-6 hours.

6. A thermally conductive encapsulated composite material, characterized in that the thermally conductive encapsulated composite material comprises a resin and a thermally conductive powder according to any one of claims 1-2.