阅读说明：本技术 一种低出油导热凝胶及其制备方法 (Low-oil-yield heat-conducting gel and preparation method thereof ) 是由 李春方 宋波 程龙 刘晓燕 于 2021-06-15 设计创作，主要内容包括：本申请涉及导热凝胶领域,具体公开了一种低出油导热凝胶及其制备方法。低出油导热凝胶由包括以下质量百分比的原料制成：硅油5-19%,白炭黑0.05-0.5%,偶联剂0.1-2%,硅藻土0-1%,余量为导热粉体；其制备方法为：按配比,将导热粉体、白炭黑、硅油和偶联剂混匀,搅拌30min,并于120℃下加热2h,得低出油导热凝胶。本申请的低出油导热凝胶,在具有较低的出油率的同时又具有一定的挤出速率。(The application relates to the field of heat-conducting gel, and particularly discloses low-oil-yield heat-conducting gel and a preparation method thereof. The low-oil-yield heat-conducting gel is prepared from the following raw materials in percentage by mass: 5-19% of silicone oil, 0.05-0.5% of white carbon black, 0.1-2% of coupling agent, 0-1% of diatomite and the balance of heat-conducting powder; the preparation method comprises the following steps: mixing the heat-conducting powder, the white carbon black, the silicone oil and the coupling agent uniformly according to the proportion, stirring for 30min, and heating for 2h at 120 ℃ to obtain the low-oil-yield heat-conducting gel. The low-oil-yielding heat-conducting gel has a certain extrusion rate while having a lower oil yielding rate.)

1. The low-oil-yield heat-conducting gel is characterized by being prepared from the following raw materials in percentage by mass: 5-19% of silicone oil, 0.05-0.5% of white carbon black, 0.1-2% of coupling agent, 0-1% of diatomite and the balance of heat-conducting powder.

2. The low oil extraction thermal conductive gel of claim 1, wherein: the white carbon black is fumed silica, and the specific surface area of the fumed silica is 140-220.

3. The low oil extraction thermal conductive gel of claim 1, wherein: the heat conducting powder is selected from one or more of aluminum oxide, zinc oxide, boron nitride, aluminum nitride, silicon dioxide and aluminum hydroxide.

4. The low oil extraction thermal conductive gel of claim 3, wherein: the grain diameter of the heat-conducting powder is 0.5-70 μm.

5. The low oil extraction thermal conductive gel of claim 4, wherein: the grain diameter of the heat-conducting powder is 40-50 μm.

6. The low oil extraction thermal conductive gel of claim 1, wherein: the silicone oil is selected from one or more of vinyl silicone oil, phenyl silicone oil, hydroxyl silicone oil, dimethyl silicone oil, polyether modified silicone oil and long-chain alkyl silicone oil, and the viscosity of the silicone oil is 350-2000 cps.

7. The low oil extraction thermal conductive gel of claim 1, wherein: the coupling agent is selected from one or more of propyl trimethoxy silane, decyl trimethoxy siloxane, phenyl siloxane, gamma-aminopropyl triethoxy silane and gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane.

8. The low oil extraction thermal conductive gel of claim 1, wherein: the weight percentage of the diatomite is 0.5-1%.

9. The method for preparing a low oil-out thermally conductive gel as claimed in any one of claims 1 to 7, wherein: mixing the heat-conducting powder, the white carbon black, the silicone oil and the coupling agent uniformly according to the proportion, stirring for 30min, and heating for 2h at 120 ℃ to obtain the low-oil-yield heat-conducting gel.

Technical Field

The application relates to the field of heat-conducting gel, in particular to low-oil-yield heat-conducting gel and a preparation method thereof.

Background

At present, in the mobile phone industry, the heat productivity of a CPU and a GPU chipset in the mobile phone is increased more and more, a certain gap is inevitably formed between a heat source such as the CPU and the GPU and a metal shielding case, the existence of the gap can increase the contact thermal resistance of air, the rapid heat transmission of a chip can be seriously influenced, and the trouble is caused to the heat dissipation of the chip. In order to solve the problem, a heat-conducting interface material is usually filled between a heat source and a heat sink, and a heat-conducting gel is used as a heat-conducting medium, so that the heat-conducting gel has excellent heat-conducting property, aging resistance and electrical insulation property, can reduce the damage of the heat source such as a chip and the like due to poor heat dissipation, and can prolong the service life of components such as the chip and the like.

The heat-conducting rubber is a paste-shaped gap filling material which is formed by mixing and processing silicone resin, heat-conducting, heat-resisting and insulating materials and the like through a process, and in the long-time use process, the heat-conducting gel can generate an oil phenomenon due to long-time heating and extrusion. A small amount of oil is in a normal condition, the normal use of the heat-conducting gel is not influenced, but the leaked oil is easily adsorbed on the heating element and the radiator due to a large amount of oil, so that the normal use performance of the heating element and the radiator is influenced.

In view of the above-mentioned related technologies, the inventors believe that although the oil yield of the heat-conducting gel can be reduced by partially crosslinking vinyl silicone oil and hydrogen-containing silicone oil, the extrusion rate is reduced during the production of the heat-conducting gel, which affects the production efficiency to some extent.

Disclosure of Invention

In order to reduce the oil yield of the heat-conducting gel and ensure that the heat-conducting gel has a certain extrusion rate, the application provides the low-oil-yield heat-conducting gel and the preparation method thereof.

In a first aspect, the present application provides a low oil-out heat-conducting gel, which adopts the following technical scheme:

the low oil yield heat conducting gel consists of silicone oil 5-19 wt%, white carbon black 0.05-0.5 wt%, coupling agent 0.1-2 wt%, diatomite 0-1 wt% and heat conducting powder for the rest.

By adopting the technical scheme, the silicone oil is used as the base material of the heat-conducting gel, has excellent heat resistance, weather resistance, compression resistance and viscosity, and can be effectively filled and adhered between the heating body and the heat radiation body; the heat conducting powder is utilized to ensure that the heat conducting gel has better heat conducting performance, so that the heat generated by the heating body can be transferred to the heat radiating body through the heat conducting gel, and the aim of quickly radiating heat is fulfilled; the white carbon black has better high temperature resistance and electrical insulation property, and meanwhile, the thixotropy of the white carbon black can enable the heat-conducting gel to have certain fluidity, so that the heat-conducting gel is filled between the heating body and the heat radiation body and infiltrates a solid interface in contact with the heating body and the heat radiation body, and meanwhile, the heat-conducting gel has certain extrusion rate, and the integral production efficiency is improved; the organic functional group of the coupling agent can be combined with the silicone oil, and the inorganic functional group of the coupling agent can be combined with the heat-conducting powder and the white carbon black, so that the compatibility among the heat-conducting powder, the white carbon black and the silicone oil can be improved, and the possibility of oil outflow of the heat-conducting gel is reduced.

Preferably, the white carbon black is fumed silica, and the specific surface area of the fumed silica is 140-220.

By adopting the technical scheme, the fumed silica has stronger surface adsorption force and better thixotropy, and the fumed silica with a specific surface area can ensure that the heat-conducting gel has certain fluidity, so that the heat-conducting gel can have certain extrusion rate while the oil yield of the heat-conducting gel is reduced.

Preferably, the heat conducting powder is selected from one or more of alumina, zinc oxide, boron nitride, aluminum nitride, silicon dioxide and aluminum hydroxide.

By adopting the technical scheme, the heat-conducting gel can be endowed with better heat-conducting property.

Preferably, the particle size of the heat-conducting powder is 0.5-70 μm.

By adopting the technical scheme, the specific particle size is beneficial to dispersing the heat-conducting powder in a heat-conducting gel system and forming a heat-conducting passage, so that the heat-conducting gel has better heat-conducting performance.

Preferably, the particle size of the heat-conducting powder is 40-50 μm.

By adopting the technical scheme, the heat conduction powder can be dispersed in a heat conduction gel system and an effective heat conduction path can be formed.

Preferably, the silicone oil is selected from one or more of vinyl silicone oil, phenyl silicone oil, hydroxyl silicone oil, dimethyl silicone oil, polyether modified silicone oil and long-chain alkyl silicone oil, and the viscosity of the silicone oil is 350-2000 cps.

By adopting the technical scheme, the viscosity of the silicone oil influences the oil yield of the heat-conducting gel to a certain extent, and the larger the viscosity of the silicone oil is, the larger the resistance of free silicone oil molecules in the system is, so that the oil yield is smaller; however, the larger the viscosity of the silicone oil is, the smaller the overall fluidity of the heat-conducting gel is, and the foam discharge is not facilitated during preparation, which affects the usability of the heat-conducting gel. By selecting the silicone oil with specific viscosity, the oil yield can be reduced while the silicone oil has better service performance.

Preferably, the coupling agent is selected from one or more of propyl trimethoxy silane, decyl trimethoxy siloxane, phenyl siloxane, gamma-aminopropyl triethoxy silane, and gamma- (2, 3-glycidoxy) propyl trimethoxy silane.

By adopting the technical scheme, the compatibility among the heat-conducting powder, the white carbon black and the silicone oil is favorably improved, so that the heat-conducting powder can form an effective heat-conducting passage in a system, and the heat-conducting gel has better fluidity.

Preferably, the weight percentage of the diatomite is 0.5-1%.

By adopting the technical scheme, the diatomite has strong absorbability and more pores, free silicone oil molecules in the heat-conducting gel can be filled in the pores of the diatomite, and the diatomite can be used for hindering the movement of the free silicone oil molecules, so that the oil yield of the heat-conducting gel is further reduced.

In a second aspect, the application provides a preparation method of a low oil-yielding heat-conducting gel, which adopts the following technical scheme:

a preparation method of low-oil-yield heat-conducting gel comprises the steps of uniformly mixing heat-conducting powder, white carbon black, silicone oil and a coupling agent according to a ratio, stirring for 30min, and heating at 120 ℃ for 2h to obtain the low-oil-yield heat-conducting gel. .

By adopting the technical scheme, the heat-conducting gel with high heat conductivity, high extrusion rate and low oil yield can be prepared.

In summary, the present application has the following beneficial effects:

1. this application utilizes white carbon black to make heat conduction gel have certain mobility, utilizes the coupling agent to improve the compatibility between silicone oil and heat conduction powder, the white carbon black to make heat conduction gel have lower oil yield, have certain extrusion rate again simultaneously.

2. This application is through adding diatomaceous earth for free silicone oil molecule can be filled in the hole of diatomaceous earth, thereby can reduce the motion of free silicone oil molecule, has further reduced the oil yield of heat conduction gel.

Detailed Description

The present application will be described in further detail with reference to examples.

The sources of the individual raw material components in this application are shown in table 1.

Table 1 sources of the respective raw materials.

Examples

Example 1

A low oil-yielding heat-conducting gel is prepared from the following raw materials: 919.5g of heat-conducting powder, 0.5g of fumed silica, 60g of silicone oil and 20g of coupling agent. Wherein, the heat conducting powder can be one of alumina, zinc oxide, boron nitride, aluminum nitride, silicon dioxide and aluminum hydroxide, and the alumina with the grain diameter of 0.5 μm is selected in the embodiment; the silicone oil can be selected from one of vinyl silicone oil, phenyl silicone oil, hydroxyl silicone oil, dimethyl silicone oil, polyether modified silicone oil and long-chain alkyl silicone oil, and the vinyl silicone oil with the viscosity of 140cps is selected in the embodiment; the coupling agent can be one of propyl trimethoxy silane, decyl trimethoxy siloxane, phenyl siloxane, gamma-aminopropyl triethoxy silane and gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane, and propyl trimethoxy silane is selected in the embodiment; the white carbon black is fumed silica, and the specific surface area is 140.

The preparation method of the low-oil-yielding heat-conducting gel comprises the following steps: mixing the heat-conducting powder, the white carbon black, the silicone oil and the coupling agent, stirring for 30min, and heating at 120 ℃ for 2h to obtain the low-oil-yield heat-conducting gel.

Example 2

A low oil-yielding heat-conducting gel is prepared from the following raw materials: 930g of heat-conducting powder, 5g of fumed silica, 50g of silicone oil and 15g of coupling agent. The heat conducting powder is alumina with the grain diameter of 0.5, the silicone oil is vinyl silicone oil with the viscosity of 140cps, the coupling agent is propyl trimethoxy silane, the white carbon black is fumed silica, and the specific surface area is 140.

Example 3

A low oil-yielding heat-conducting gel is prepared from the following raw materials: 872.6g of heat-conducting powder, 1.7g of fumed silica, 118.3g of silicone oil and 7.4g of coupling agent. The heat conducting powder is alumina with the grain diameter of 0.5, the silicone oil is vinyl silicone oil with the viscosity of 140cps, the coupling agent is propyl trimethoxy silane, the white carbon black is fumed silica, and the specific surface area is 140.

Example 4

A low oil-yielding heat-conducting gel is prepared from the following raw materials: 846.4g of heat-conducting powder, 2.6g of fumed silica, 150g of silicone oil and 1g of coupling agent. The heat conducting powder is alumina with the grain diameter of 0.5, the silicone oil is vinyl silicone oil with the viscosity of 140cps, the coupling agent is propyl trimethoxy silane, the white carbon black is fumed silica, and the specific surface area is 140.

Example 5

A low oil-yielding heat-conducting gel is prepared from the following raw materials: 800g of heat-conducting powder, 5g of fumed silica, 190g of silicone oil and 5g of coupling agent. The heat conducting powder is alumina with the grain diameter of 0.5, the silicone oil is vinyl silicone oil with the viscosity of 140cps, the coupling agent is propyl trimethoxy silane, the white carbon black is fumed silica, and the specific surface area is 140.

Example 6

This example differs from example 1 only in that the particle size of alumina is 5 μm.

Example 7

This example differs from example 1 only in that the particle size of alumina is 20 μm.

Example 8

This example differs from example 1 only in that the particle size of alumina is 40 μm.

Example 9

This example differs from example 1 only in that the particle size of alumina is 45 μm.

Example 10

This example differs from example 1 only in that the particle size of alumina is 48 μm.

Example 11

This example differs from example 1 only in that the particle size of alumina is 50 μm.

Example 12

This example differs from example 1 only in that the particle size of alumina is 60 μm.

Example 13

This example differs from example 1 only in that the particle size of alumina is 70 μm.

Example 14

This example differs from example 1 only in that the particle size of alumina is 0.2 μm.

Example 15

This example differs from example 1 only in that the vinyl silicone oil has a viscosity of 500 cps.

Example 16

This example differs from example 1 only in that the vinyl silicone oil has a viscosity of 800 cps.

Example 17

This example differs from example 1 only in that the vinyl silicone oil has a viscosity of 1500 cps.

Example 18

This example differs from example 1 only in that the vinyl silicone oil has a viscosity of 2000 cps.

Example 19

This example differs from example 1 only in that the vinyl silicone oil has a viscosity of 3000 cps.

Example 20

The present example is different from example 1 only in that fumed silica has a specific surface area of 160.

Example 21

The present example is different from example 1 only in that fumed silica has a specific surface area of 190.

Example 22

The present example is different from example 1 only in that fumed silica has a specific surface area of 220.

Example 23

The present example is different from example 1 only in that the fumed silica has a specific surface area of 100.

Example 24

The only difference between this example and example 1 is that the white carbon black is precipitated white carbon black.

Example 25

The present example is different from example 1 only in that the raw material for preparing the low oil-yielding thermal conductive gel further comprises 5g of diatomite, and the mixing amount of the thermal conductive powder is 914.5 g.

Example 26

The present example is different from example 1 only in that the raw material for preparing the low oil-yielding thermal conductive gel further comprises 7g of diatomite, and the mixing amount of the thermal conductive powder is 912.5 g.

Example 27

The present example is different from example 1 only in that the raw material for preparing the low oil-yielding thermal conductive gel further comprises 8g of diatomite, and the mixing amount of the thermal conductive powder is 911.5 g.

Example 28

The present example is different from example 1 only in that the raw material for preparing the low oil-yielding thermal conductive gel further comprises 10g of diatomite, and the mixing amount of the thermal conductive powder is 909.5 g.

Example 29

The present example is different from example 1 only in that the raw material for preparing the low oil-yielding thermal conductive gel further comprises 2g of diatomite, and the mixing amount of the thermal conductive powder is 917.5 g.

Example 30

This example differs from example 1 only in that the vinyl silicone oil is replaced by an equal amount of dimethicone.

Comparative example

Comparative example 1

Comparative example 1 differs from example 30 only in that fumed silica is not added.

Comparative example 2

A high-performance heat-conducting silica gel is prepared from a component A and a component B in a mass ratio of 1: 1, wherein the component A comprises 16g of vinyl-terminated silicone oil (the vinyl content is 0.3 wt%), 84g of alumina filler and 0.002g of platinum catalyst; the component B comprises 14g of vinyl-terminated silicone oil (the vinyl content is 0.3 percent), 84.6g of alumina filler, 1.02g of hydrogen-terminated silicone oil (the hydrogen content is 0.15 percent), 0.425g of cross-linking agent (the hydrogen content is 0.3 percent) and 0.0002g of 3-methyl-1-butyn-3-ol.

The high-performance heat-conducting silica gel is prepared by the following method:

1) preparation of component A: evenly mixing vinyl-terminated silicone oil, alumina filler and platinum catalyst to obtain a component A;

2) preparation of the component B: evenly mixing hydrogen-containing silicone oil, alumina filler, a cross-linking agent and 3-methyl-1-butyn-3-ol to obtain a component B;

the preparation method of the cross-linking agent comprises the following steps:

a. putting 219.6g of hexyl trichlorosilane, 45.5g of dimethylchlorosilane and 54.3g of toluene into a reaction kettle, and cooling to below 5 ℃ under stirring;

b. adding a mixed solution of 69g of tetrahydrofuran and 31.3g of water, heating to 80 ℃ in an oil bath, and continuously stirring for 2 hours;

c. adding 16.8g of saturated sodium bicarbonate aqueous solution to make the reaction solution alkaline, continuing stirring for 1.5h, adding 4.7g of water, and stirring for 3 h;

d. sequentially washing the slurry-like reactant with an acetic acid aqueous solution, a saturated sodium bicarbonate aqueous solution and water, drying and distilling off the solvent to obtain a colorless and transparent Si-H-based polymer;

3) uniformly mixing the component A and the component B according to the mass ratio of 1: 1, defoaming in vacuum, heating at 120 ℃ for 20min, and curing to obtain the high-performance silicon rubber.

Comparative example 3

This comparative example differs from example 1 only in that the white carbon black was replaced with an equal amount of propyltrimethoxysilane.

Comparative example 4

The comparative example is different from example 1 only in that the blending amount of fumed silica is 0.2g and the blending amount of coupling agent is 10 g.

Performance test

Test one, the thermal conductivity of the thermally conductive gels in each example and each comparative example was tested with reference to ASTM D5470-2006.

Test two, using a 30ml american rubber cylinder, the rubber cylinder was pressed using an air pressure of 0.6MPa, and the extrusion efficiency of the thermally conductive gel in each example and each comparative example was characterized in terms of the weight of the discharged gel per minute.

And testing III, namely weighing the test sample in advance, placing the test sample in a filter paper layer, then placing the test sample in an oven at 120 ℃ for baking for 24 hours, weighing again, and calculating the oil yield of the heat-conducting gel according to the oil yield = (initial weight-final weight)/initial weight 100%.

TABLE 2 Performance test results

Referring to table 2, it can be seen from the combination of example 1, example 30, comparative example 1, comparative example 2 and comparative example 3 that, although the heat conductive gel has a low oil yield, the extrusion rate of the heat conductive gel is also reduced by using the vinyl silicone oil and the hydrogen-containing silicone oil, as can be seen from table 2, after the white carbon black is added in the present application, the heat conductive gel in example 1 has a low oil yield, and the extrusion rate is higher than that in comparative example 2 and comparative example 3, which indicates that the white carbon black added in the present application not only can make the heat conductive gel have a low oil yield, but also can make the heat conductive gel have a certain fluidity, so that the heat conductive gel has a certain extrusion rate.

With reference to example 1, example 6 to example 14, the thermal conductivity of the thermal conductive gel gradually increases with the gradually increasing particle size of the alumina, which shows that the larger the particle size of the alumina is, the more the alumina is in contact with each other in the thermal conductive gel system, so as to facilitate the formation of the thermal conductive path and improve the thermal conductivity. Meanwhile, the oil yield of the heat-conducting gel in the embodiments 6 to 14 is less changed, and the extrusion rate of the heat-conducting gel is increased along with the increase of the particle size of the alumina, and the analysis shows that the oil absorption value of the alumina with larger particle size is relatively lower, and the thickening effect is not obvious, so that the heat-conducting gel has certain fluidity, and the increase of the extrusion rate of the heat-conducting gel is further shown.

Referring to example 1, example 15 to example 19, as the viscosity of the silicone oil gradually increases, the oil yield and the extrusion rate of the heat-conducting gel gradually decrease, and the change of the heat-conducting property is small, which shows that the viscosity change of the silicone oil mainly affects the fluidity of the heat-conducting gel, so that the heat-conducting gel shows a low extrusion rate, and the larger the viscosity of the silicone oil is, the larger the resistance force of the silicone oil molecules is, so that the oil yield of the heat-conducting gel can be reduced.

With reference to example 1, example 20 to example 23, with the specific surface area of the fumed silica gradually increasing, both the extrusion rate and the oil yield of the heat-conducting gel are reduced, which indicates that the larger specific surface area can contribute to improving the adsorptivity and thixotropy of the fumed silica, so that the raw material components in the heat-conducting gel system can be tightly combined, and the oil yield of the heat-conducting rubber is reduced; meanwhile, while the close combination of the raw material components is enhanced, the fluidity of the heat-conducting gel is also affected, which means that the extrusion rate of the heat-conducting gel is reduced. In addition, it can be known from example 24 that the fumed silica is more conducive to reducing the oil yield of the thermal conductive gel and ensuring that the thermal conductive gel has a certain extrusion rate.

With reference to example 1, example 25 to example 29, the addition of diatomaceous earth to the heat conductive gel system has little influence on the heat conductive performance and the extrusion rate of the heat conductive gel, but can effectively reduce the oil yield of the heat conductive gel, which indicates that free silicone oil molecules in the heat conductive gel can be filled into the pores of the diatomaceous earth, so that the movement of the free silicone oil molecules is limited, and the oil yield of the heat conductive gel can be reduced.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.