High-thermal-conductivity peelable wave-absorbing gel and preparation method thereof

Abstract

The invention discloses high-heat-conductivity peelable wave-absorbing gel and a preparation method thereof, and relates to the technical field of heat-conducting wave-absorbing materials. The high-heat-conductivity peelable wave-absorbing gel is prepared from the following raw materials in parts by mass: 3 to 4 parts of vinyl silicone oil, 0.1 to 0.2 part of hydrogen-containing silicone oil, 1 to 3 parts of methyl silicone oil, 0.1 to 0.5 part of coupling agent, 60 to 65 parts of heat-conducting filler, 55 to 60 parts of modified carbonyl iron powder, 0.01 to 0.03 part of inhibitor and 0.01 to 0.1 part of catalyst, and the modified carbonyl iron powder is spherical carbonyl iron powder coated with boron nitride on the surface. The high-heat-conductivity peelable wave-absorbing gel has the characteristics of high heat conductivity coefficient, strong wave-absorbing performance and complete peeling and no residue after curing at the same time under the moderate filling amount, and the technical contradiction that high heat conductivity, strong wave-absorbing performance and easy peeling are difficult to consider at the same time in an existing material is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat-conducting wave-absorbing materials, and particularly relates to a high-heat-conducting strippable wave-absorbing gel suitable for communication, optical modules, servers and automobile electronics and a preparation method thereof. BACKGROUND

[0002] With the rapid development of science and technology, electronic devices are gradually miniaturized and high-performing, and the electronic integration in the devices is greatly increased, and the distance between electronic components is reduced. Therefore, there are higher requirements for heat dissipation products: in a limited space, the material not only needs to have excellent heat conduction performance to solve the heat dissipation problem caused by high power density, but also should be able to absorb electromagnetic waves of a specific frequency band to suppress electromagnetic interference (EMI) generated by high-frequency and high-speed circuits. In addition, in order to meet the needs of production debugging and after-sales maintenance, the material should have the characteristics of easy and complete stripping after point gluing construction and solidification, so as to realize rapid repair and improve production and maintenance efficiency.

[0003] However, the common heat-conducting wave-absorbing materials on the market often need to fill a large amount of functional powder in order to simultaneously realize high thermal conductivity and wave-absorbing performance. High filling amount can improve functionality, but it will significantly affect the process performance and mechanical state of the material: on the one hand, in order to maintain the extrudability of construction, the strength of the matrix or the addition of dilution components is usually sacrificed, resulting in low overall strength and insufficient cohesion of the material after solidification; on the other hand, the high-filled interface material is often strongly combined or penetrated with the substrate after solidification, and it is difficult to achieve complete stripping, which increases the operation difficulty and device damage risk during repair. SUMMARY

[0004] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a high-heat-conducting strippable wave-absorbing gel which can realize the coordination of high heat conduction and high wave-absorbing performance while maintaining good extrudability and construction convenience, and exhibit appropriate tensile elasticity and cohesive strength after solidification, so as to be able to be completely and cleanly stripped from the application interface, meeting the multiple requirements of heat conduction performance, wave-absorbing performance and maintainability of electronic devices.

[0005] Another purpose of the present application is to provide a preparation method of the high-heat-conducting strippable wave-absorbing gel.

[0006] The present application provides the following technical solutions: In a first aspect, the present application provides a high-heat-conducting strippable wave-absorbing gel, the raw materials of which include the following components in mass fraction: vinyl silicone oil: 3-4 parts; hydrogen-containing silicone oil: 0.1-0.2 parts; methyl silicone oil: 1-3 parts; coupling agent: 0.1-0.5 parts; Thermal conductive filler: 60-65 parts; Modified carbonyl iron powder: 55-60 parts; Inhibitor: 0.01-0.03 parts; Catalyst: 0.01-0.1 parts; The modified carbonyl iron powder is spherical carbonyl iron powder coated with boron nitride on the surface.

[0007] Preferably, the high-thermal-conductivity strippable wave-absorbing gel comprises the following components by mass fraction: Vinyl silicone oil: 3.5 parts; Hydrogen-containing silicone oil: 0.15 parts; Methyl silicone oil: 2 parts; Coupling agent: 0.3 parts; Thermal conductive filler: 64.1 parts; Modified carbonyl iron powder: 59.5 parts; Inhibitor: 0.015 parts; Catalyst: 0.05 parts.

[0008] Preferably, the viscosity of the vinyl silicone oil is 100 cp; the viscosity of the hydrogen-containing silicone oil is 100 cp; and the viscosity of the methyl silicone oil is 100 cp.

[0009] Further, the modified carbonyl iron powder is prepared by the following method: 25-35 parts of boron nitride powder is dissolved in 200 parts of dimethylbenzene to obtain a boron nitride solution, 2-3 parts of acrylic glue is added to 20 parts of spherical hydroxyl iron powder, and then the boron nitride solution is added and mixed uniformly, followed by suction filtration and drying to obtain the modified hydroxyl iron powder.

[0010] Preferably, the medium particle size of the boron nitride is 1.5-2 microns, and the medium particle size of the spherical carbonyl iron powder is 8-13 microns.

[0011] Preferably, in the modified carbonyl iron powder, the mass ratio of boron nitride to spherical carbonyl iron powder is 3:2.

[0012] Preferably, the thermal conductive filler comprises magnesium oxide, aluminum nitride, diamond, aluminum oxide, and zinc oxide.

[0013] Preferably, the mass ratio of the magnesium oxide, aluminum nitride, diamond, aluminum oxide, and zinc oxide is 26:10:(1.5-2.0):(11-11.5):15.

[0014] Preferably, the mass ratio of the magnesium oxide, aluminum nitride, diamond, aluminum oxide, and zinc oxide is 26:10:1.8:11.3:15.

[0015] Preferably, the medium particle size of the magnesium oxide is 45-55 microns, the medium particle size of the aluminum nitride is 4-6 microns, the medium particle size of the diamond is 1-3 microns, the medium particle size of the aluminum oxide is 8-13 microns, and the medium particle size of the zinc oxide is 0.1-1 micron.

[0016] Preferably, the medium particle size of the magnesium oxide is 50 microns, the medium particle size of the aluminum nitride is 5 microns, the medium particle size of the diamond is 2 microns, the medium particle size of the aluminum oxide is 10 microns, and the medium particle size of the zinc oxide is 0.5 micron.

[0017] Preferably, the coupling agent is hexadecyl trimethoxysilane; the inhibitor is 1-butynyl cyclohexanol, and the catalyst is a coated chloroplatinic acid catalyst.

[0018] In a second aspect, the present application further provides a preparation method of the high-thermal-conductivity peelable wave-absorbing gel, which comprises the following steps: adding vinyl silicone oil, hydrogen-containing silicone oil, methyl silicone oil, a coupling agent, a thermal-conductivity filler, modified carbonyl iron powder, an inhibitor and a catalyst in proportion, stirring at a speed of 1500 r / min for 60 s, and then stirring at a speed of 1000 r / min under vacuum for 60 s to obtain the high-thermal-conductivity peelable wave-absorbing gel.

[0019] The present application has the following technical effects: The present application coats boron nitride on the surface of spherical carbonyl iron powder to prepare a composite powder (modified carbonyl iron powder) with high thermal conductivity and enhanced wave-absorbing performance. This design solves the functional integration problem of thermal conduction paths and wave-absorbing units at the molecular / microscopic level, so that the gel can simultaneously obtain excellent thermal conductivity and wave-absorbing performance under a relatively low overall filler load, thereby avoiding problems such as excessive fillers, hardened gel, and excessively strong interface adhesion caused by single pursuit of high performance, and effectively solving the technical problem that high thermal conductivity, strong wave-absorbing performance and easy peeling cannot be simultaneously achieved. DETAILED DESCRIPTION

[0020] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] It should be understood that, when used in the specification and the appended claims, the terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or collections thereof.

[0022] Highly thermally conductive peelable wave-absorbing gel The raw materials include the following components in terms of mass fraction: Vinyl silicone oil: 3-4 parts; Hydrogen-containing silicone oil: 0.1-0.2 parts; Methyl silicone oil: 1-3 parts; Coupling agent: 0.1-0.5 parts; Thermal conductive filler: 60-65 parts; Modified carbonyl iron powder: 55-60 parts; Inhibitor: 0.01-0.03 parts; Catalyst: 0.01-0.1 parts; The modified carbonyl iron powder is spherical carbonyl iron powder coated with boron nitride on the surface.

[0023] Preferably, the thermal conductive filler includes magnesium oxide, aluminum nitride, diamond, aluminum oxide, and zinc oxide.

[0024] Preferably, the mass ratio of the magnesium oxide, aluminum nitride, diamond, aluminum oxide, and zinc oxide is 26:10:(1.5-2.0):(11-11.5):15.

[0025] Preferably, the medium particle size of the magnesium oxide is 50 microns, the medium particle size of the aluminum nitride is 5 microns, the medium particle size of the diamond is 2 microns, the medium particle size of the aluminum oxide is 10 microns, and the medium particle size of the zinc oxide is 0.5 microns.

[0026] Preferably, the coupling agent is hexadecyltrimethoxysilane (9116), the inhibitor is 1-butyne cyclohexanol, and the catalyst is chloroplatinic acid.

[0027] Preferably, the boron nitride is flaky boron nitride with a medium particle size of 1-30 microns, and the spherical carbonyl iron powder is spherical carbonyl iron powder with a medium particle size of 10 microns. The small particle size flaky boron nitride can wrap the spherical carbonyl iron powder, which can increase the thermal conductivity of the spherical carbonyl iron powder. The mutual dielectric effect of the boron nitride and the carbonyl iron powder can enhance the wave absorption performance.

[0028] The carbonyl iron powder is prepared by the following method: S1, preparing a boron nitride solution: taking 20-50 g of flaky boron nitride powder with a medium particle size of 1-30 microns, adding 200 g of dimethylbenzene, and stirring uniformly to obtain the boron nitride solution.

[0029] S2, premixing: taking 10-30 g of spherical carbonyl iron powder with a medium particle size of 10 microns, adding 2-5 g of acrylic glue, and stirring uniformly.

[0030] S3, adding the premixed carbonyl iron powder into the boron nitride solution of step 1 and stirring uniformly.

[0031] S4, post-processing: the mixture treated in step S3 is filtered with xylene for 3 times, and dried, to obtain the modified carbonyl iron powder.

[0032] Preferably, in step S1, the stirring is: stirring at 300 r / min for 2h under sealed conditions using a mechanical stirrer.

[0033] Preferably, in step S2, the stirring is: high-speed mixing for 3 minutes at 2000 r / min using a homogenizer, so that the acrylic adhesive uniformly wraps the surface of the carbonyl iron powder.

[0034] Preferably, in step S3, the stirring is: stirring at 100 r / min for 2h using a mechanical stirrer, so that the sheet-shaped boron nitride gradually coats the surface of the carbonyl iron powder under the adhesion.

[0035] Preferably, in step S4, the drying is: drying in a 80℃ vacuum oven for 6 hours.

[0036] The preparation method of the highly thermally conductive peelable wave-absorbing gel is as follows: Mix the vinyl silicone oil, hydrogen-containing silicone oil, methyl silicone oil, coupling agent, thermal conductive filler, modified carbonyl iron powder, inhibitor and catalyst in proportion, then stir at 1500 r / min for 60s using a homogenizer, and then stir at 1000 r / min for 60s under vacuum conditions, to obtain the high-thermal-conductivity peelable wave-absorbing gel.

[0037] Examples and comparative examples: To verify the influence of the modified carbon-based iron powder on the high-thermal-conductivity peelable wave-absorbing gel, the modified carbonyl iron powders A-K were prepared, and the content of each raw material in the modified carbonyl iron powders A-K is shown in Table 1. Table 1 Content of each raw material in the modified carbonyl iron powders A-K The above modified carbonyl iron powder is prepared by the following method: S1, preparation of boron nitride solution: take the boron nitride powder and add it into xylene, and stir at 300 r / min for 2h under sealed conditions using a mechanical stirrer, to obtain the boron nitride solution.

[0038] S2, premixing: take the spherical carbonyl iron powder and add the acrylic adhesive, and high-speed mix at 2000 r / min for 3 minutes using a homogenizer, so that the acrylic adhesive uniformly wraps the surface of the carbonyl iron powder.

[0039] S3, add the premixed carbonyl iron powder into the boron nitride solution of step 1, and stir at 100 r / min for 2h using a mechanical stirrer, so that the sheet-shaped boron nitride gradually coats the surface of the carbonyl iron powder under the adhesion.

[0040] S4, post-treatment: the mixture treated in step S3 was filtered with xylene for 3 times, and then was dried in a vacuum oven at 80℃ for 6 hours to obtain the modified carbonyl iron powder.

[0041] The modified carbonyl iron powder A-K and the unmodified carbonyl iron powder were used to prepare wave-absorbing gels according to the preparation method of the high-thermal-conductivity peelable wave-absorbing gel to obtain examples 1-4 and comparative examples 1-8. The content of each component in the examples and comparative examples is shown in Table 2. Table 2 Content of each component in examples and comparative examples The wave-absorbing gels in the examples and comparative examples were tested for thermal conductivity, peelability, wave-absorbing intensity and extrudability, and the test methods are as follows: Thermal conductivity: the thermal conductivity of the cured sample was tested by a heat flow method according to ASTM D5470 standard.

[0042] Wave-absorbing intensity: the reflection loss (dB) of the sample to electromagnetic waves was tested by a waveguide method at a frequency of 5 GHz using a vector network analyzer, and a negative value indicates absorption, and the greater the absolute value, the stronger the wave-absorbing performance.

[0043] Extrudability: the mass of the gel (g / min) extruded per unit time was tested under a fixed pressure using a standard dispensing device and a needle, which represents the construction process performance.

[0044] Interface peel test: the gel was point-coated on a standard FR-4 PCB board, covered with an aluminum plate and pressed to a thickness of 2 mm, and then cured in an oven at 80℃ for 15 minutes. After cooling to room temperature, the cured gel layer was manually peeled off, and the interface of the PCB board was observed by visual observation and microscope to determine whether there was residual gel, and the difficulty of the peeling process and the integrity of the gel were evaluated.

[0045] The test results are shown in Table 3. Table 3 Performance test results As shown in Table 3, the high-thermal-conductivity peelable wave-absorbing gel prepared in examples 1-4 has excellent and balanced performance in terms of thermal conductivity, interface peelability, wave-absorbing intensity and extrudability. However, the comparative examples failed to achieve the synergistic effect of high thermal conductivity, strong wave-absorbing, easy peeling and good extrudability due to improper component ratio (comparative examples 1-3), improper particle size matching (comparative examples 4, 5 and 8) or invalid coating structure (comparative examples 6 and 7).

[0046] In conclusion, by adopting the spherical carbonyl iron powder coated with boron nitride on the surface as the modified wave-absorbing filler, the comprehensive performance of the material is significantly improved while maintaining a high filler content, the synergistic optimization of high thermal conductivity, strong wave absorption, easy stripping and good workability is realized, and the problem that multiple performances are difficult to be considered in the prior art is effectively solved.

[0047] The above merely describes the specific implementation of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A highly thermally conductive, peelable microwave absorbing gel, characterized in that, By mass, its raw materials include the following components: Vinyl silicone oil: 3-4 parts; Hydrogen-containing silicone oil: 0.1-0.2 parts; Methyl silicone oil: 1-3 parts; Coupling agent: 0.1-0.5 parts; Thermally conductive filler: 60-65 parts; Modified carbonyl iron powder: 55-60 parts; Inhibitor: 0.01-0.03 parts; Catalyst: 0.01-0.1 parts; The modified carbonyl iron powder is a spherical carbonyl iron powder with boron nitride coated on its surface.

2. The high thermal conductivity peelable microwave absorbing gel as described in claim 1, characterized in that, The modified carbonyl iron powder is prepared by the following method: 25-35 parts by mass of boron nitride powder are dissolved in 200 parts by xylene and stirred evenly to obtain a boron nitride solution. 2-3 parts by mass of spherical hydroxyl iron powder are added to acrylic glue and mixed evenly. The boron nitride solution is then added and mixed evenly. The mixture is then filtered and dried to obtain the modified hydroxyl iron powder.

3. The high thermal conductivity peelable microwave absorbing gel as described in claim 2, characterized in that, The boron nitride has a medium particle size of 1.5-2 micrometers, and the spherical carbonyl iron powder has a medium particle size of 8-13 micrometers.

4. The high thermal conductivity peelable microwave absorbing gel as described in claim 2, characterized in that, In the modified carbonyl iron powder, the mass ratio of boron nitride to spherical carbonyl iron powder is 3:

2.

5. The high thermal conductivity peelable microwave absorbing gel as described in claim 2, characterized in that, The boron nitride is in the form of flakes.

6. The high thermal conductivity peelable microwave absorbing gel as described in claim 1, characterized in that, The thermally conductive filler includes magnesium oxide, aluminum nitride, diamond, aluminum oxide, and zinc oxide.

7. The high thermal conductivity peelable microwave absorbing gel as described in claim 6, characterized in that, The mass ratio of magnesium oxide, aluminum nitride, diamond, aluminum oxide and zinc oxide is 26:10:(1.5-2.0):(11-11.5):

15.

8. The high thermal conductivity peelable microwave absorbing gel as described in claim 1, characterized in that, The magnesium oxide has a medium particle size of 45-55 micrometers, the aluminum nitride has a medium particle size of 4-6 micrometers, the diamond has a medium particle size of 1-3 micrometers, the aluminum oxide has a medium particle size of 8-13 micrometers, and the zinc oxide has a medium particle size of 0.1-1 micrometers.

9. The high thermal conductivity peelable microwave absorbing gel as described in claim 1, characterized in that, The coupling agent is hexadecyltrimethoxysilane; the inhibitor is 1-butynylcyclohexanol; and the catalyst is a coated chloroplatinic acid catalyst.

10. A method for preparing a high thermal conductivity peelable microwave absorbing gel as described in any one of claims 1-9, characterized in that, Includes the following steps: Vinyl silicone oil, hydrogen-containing silicone oil, methyl silicone oil, coupling agent, thermally conductive filler, modified carbonyl iron powder, inhibitor and catalyst are mixed evenly in proportion to obtain the high thermal conductivity peelable microwave absorbing gel.

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