阅读说明：本技术 耐酸碱的改性氧化铝导热粉、导热硅橡胶及其制备方法 (Acid and alkali resistant modified aluminum oxide heat conducting powder, heat conducting silicone rubber and preparation method thereof ) 是由 黄文哲 刘光华 黄琪 陈永隆 陈建军 黄恒超 于 2021-01-28 设计创作，主要内容包括：本发明公开了一种耐酸碱的改性氧化铝导热粉、导热硅橡胶及其制备方法。该耐酸碱的改性氧化铝导热粉的制备方法包括以下步骤：(1)将氢氧化铝分散于水中,得氢氧化铝浆料,在搅拌和加压的条件下加入固体水玻璃,搅拌至所述固体水玻璃完全溶解；(2)在步骤(1)所得混合物中通入二氧化碳,将溶液的pH调节至7-8,停止通气,陈化,泄压,出料；(3)将步骤(2)所得浆料依次进行过滤、水洗、干燥、煅烧、粉碎；(4)将步骤(3)所得粉体用复合表面处理剂进行表面处理改性,即得所述耐酸碱的改性氧化铝导热粉；所述复合表面处理剂为硅烷和长链脂肪酸的复配物。该改性氧化铝导热粉具有很好的耐酸碱性能,可用于制备耐酸碱的导热硅橡胶。(The invention discloses acid and alkali resistant modified aluminum oxide heat-conducting powder, heat-conducting silicon rubber and a preparation method thereof. The preparation method of the acid and alkali resistant modified aluminum oxide heat conducting powder comprises the following steps: (1) dispersing aluminum hydroxide in water to obtain aluminum hydroxide slurry, adding solid water glass under the conditions of stirring and pressurizing, and stirring until the solid water glass is completely dissolved; (2) introducing carbon dioxide into the mixture obtained in the step (1), adjusting the pH value of the solution to 7-8, stopping introducing the gas, aging, relieving pressure and discharging; (3) sequentially filtering, washing, drying, calcining and crushing the slurry obtained in the step (2); (4) carrying out surface treatment modification on the powder obtained in the step (3) by using a composite surface treating agent to obtain the acid and alkali resistant modified aluminum oxide heat conducting powder; the composite surface treating agent is a compound of silane and long-chain fatty acid. The modified aluminum oxide heat-conducting powder has good acid and alkali resistance, and can be used for preparing acid and alkali resistant heat-conducting silicone rubber.)

1. The preparation method of the acid and alkali resistant modified aluminum oxide heat conducting powder is characterized by comprising the following steps:

(1) dispersing aluminum hydroxide in water to obtain aluminum hydroxide slurry, adding solid water glass under the conditions of stirring and pressurizing, and stirring until the solid water glass is completely dissolved;

(2) introducing carbon dioxide into the mixture obtained in the step (1), adjusting the pH value of the solution to 7-8, stopping introducing the gas, aging, relieving pressure and discharging;

(3) sequentially filtering, washing, drying, calcining and crushing the slurry obtained in the step (2);

(4) carrying out surface treatment modification on the powder obtained in the step (3) by using a composite surface treating agent to obtain the acid and alkali resistant modified aluminum oxide heat conducting powder;

the composite surface treating agent is a compound of silane and long-chain fatty acid; the silane is selected from one or more of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and hydrolysis polycondensate of ethyl orthosilicate; the long-chain fatty acid is selected from one or more of oleic acid, stearic acid, lauric acid and palmitic acid.

2. The method for preparing acid and alkali resistant modified aluminum oxide heat conducting powder according to claim 1, wherein the aluminum hydroxide slurry contains 600-1200 g/L of aluminum hydroxide; and/or the presence of a gas in the gas,

heating the aluminum hydroxide slurry to 50-80 ℃ before adding the solid sodium silicate; and/or the presence of a gas in the gas,

the stirring and pressurizing conditions in the step (1) comprise: the stirring speed is 900-1500r/min, and the pressure is increased to 2-3 atmospheric pressures; and/or the presence of a gas in the gas,

the addition amount of the solid sodium silicate is 10-60% of the mass of the aluminum hydroxide; and/or the presence of a gas in the gas,

the modulus of the solid water glass is 1-3; and/or the presence of a gas in the gas,

the aging time is 2-4 hours; and/or the presence of a gas in the gas,

the calcining temperature is 1100-1300 ℃ and the calcining time is 4-8 hours.

3. The method for preparing acid and alkali resistant modified alumina heat conductive powder of claim 1, wherein the mass ratio of the silane to the long chain fatty acid is 1: 0.25-4.

4. The preparation method of the acid and alkali resistant modified aluminum oxide heat conduction powder according to claim 1, wherein the composite surface treating agent is a compound of ethyl orthosilicate and stearic acid in a mass ratio of 1: 0.8-1.2; or the composite surface treating agent is a compound of vinyl trimethoxy silane and monthly silicic acid in a mass ratio of 1: 1.8-2.2; or the composite surface treating agent is a compound of silicon-40 and oleic acid in a mass ratio of 1: 0.25-0.3.

5. The method for preparing acid and alkali resistant modified aluminum oxide heat conduction powder according to any one of claims 1 to 4, wherein the addition amount of the composite surface treating agent is 0.5 to 5 percent of the mass of the powder obtained in the step (3); and/or the presence of a gas in the gas,

the conditions for the surface treatment modification include: the stirring speed is 3000-.

6. An acid and alkali resistant modified alumina heat conductive powder, characterized in that the acid and alkali resistant modified alumina heat conductive powder is prepared by the preparation method of the acid and alkali resistant modified alumina heat conductive powder of any one of claims 1 to 5.

7. The acid and alkali resistant heat-conducting silicone rubber is characterized by comprising a component A and a component B in a mass ratio of 1:1, wherein the component A comprises the following raw material components:

100 parts by weight of double-end vinyl silicone oil,

The acid and alkali resistant modified alumina heat conducting powder as set forth in claim 6 in 50-200 weight portions,

5-20ppm of catalyst;

the component B comprises the following raw material components in parts by weight:

8. the acid and alkali resistant heat conductive silicone rubber according to claim 7, wherein the component A comprises the following raw material components:

100 parts by weight of double-end vinyl silicone oil,

The acid and alkali resistant modified alumina heat transfer powder of claim 6 comprising 180 parts by weight of,

8-12ppm of catalyst;

the component B comprises the following raw material components in parts by weight:

9. the acid and alkali resistant thermally conductive silicone rubber according to claim 7 or 8, wherein the viscosity of the double-ended vinyl silicone oil at 25 ℃ is 100-10000 mPa-s; and/or the presence of a gas in the gas,

the hydrogen content of the end side hydrogen-containing silicone oil is 0.05-1%; and/or the presence of a gas in the gas,

the catalyst is a Karster platinum catalyst; and/or the presence of a gas in the gas,

the inhibitor is an alkynol inhibitor.

10. The preparation method of the acid and alkali resistant heat conductive silicone rubber according to any one of claims 7 to 9, characterized by comprising the following steps:

preparation of component A: uniformly mixing the double-end vinyl silicone oil, the acid-base resistant modified alumina heat-conducting powder and the catalyst to obtain the catalyst;

preparation of the component B: and uniformly mixing the double-end vinyl silicone oil, the acid-base resistant modified aluminum oxide heat conduction powder, the end-side hydrogen-containing silicone oil and the inhibitor to obtain the heat conduction material.

Technical Field

The invention relates to the technical field of silicon rubber, in particular to acid and alkali resistant modified aluminum oxide heat-conducting powder, heat-conducting silicon rubber and a preparation method thereof.

Background

Along with the development of electronic equipment towards miniaturization, multi-functionalization, integration and high performance, the power consumption and the heat flux density of devices in the electronic equipment are continuously increased, the overheating problem of the electronic equipment is more and more prominent, and if the heat dissipation design cannot be effectively carried out, the reliability and the service life of a system are directly influenced. Foreign statistics show that the reliability of the electronic components is reduced by 10% when the temperature of the electronic components rises by 2 ℃, the service life of the electronic components when the temperature rises by 50 ℃ is only 1/6 when the temperature rises by 25 ℃, and the failure rate of the electronic products can be greatly increased by high-temperature factors. The heat-conducting pouring sealant, in particular to the heat-conducting silicon rubber which has the advantages of good weather resistance, low hardness, small internal stress, low volatile component, wide applicable temperature range and moisture-proof and shock-absorbing functions, is increasingly used as a heat-radiating material in the fields of printed circuit boards, power assemblies, adapters, communication electronics, wearable equipment, 5G base stations and the like.

The heat-conducting silicone rubber on the market mainly depends on the added heat-conducting powder for heat conduction, and the common heat-conducting powder comprises silicon micropowder, alumina, zinc oxide, aluminum nitride, boron nitride and the like, wherein the alumina is relatively low in price and easy to obtain, low in density, high in heat conductivity and good in compatibility with an organic silicon system, and is one of the most widely used heat-conducting powder materials. However, since alumina is an amphoteric oxide, its acid-base resistance is not good for a long period of time, and the use of the heat conductive silicone rubber in the acid-base field is limited.

The preparation method of the alumina commonly used at present mainly comprises the following steps: the preparation method comprises a pressurized hydrolysis method, a micro-emulsion method, a gas phase method, a detonation method, mechanical grinding, a hydrothermal-calcining method and the like, impurity removal is also involved in the process of preparing high-purity alumina, common methods comprise acid washing, anion/cation adsorption resin adsorption and the like, and the operations and processes are publicly and mature documents for reference.

Patent CN111732837A describes a heat conductive silicone rubber for lithium battery frame, which achieves the effect of acid and alkali resistance by adding fluorosilicone oil, but fluorosilicone oil is expensive, compatibility between high fluorosilicone oil and silicone rubber is poor, and the addition amount is limited. Patent CN101284925A describes a heat-conducting high-temperature vulcanized silicone rubber, which is prepared by blending silicone rubber and ethylene propylene diene monomer rubber to achieve the effect of acid and alkali resistance, and belongs to a silicone rubber product, and is not suitable for potting in narrow and irregular spaces inside electronic equipment, and the interface thermal resistance is also large.

Disclosure of Invention

Based on the above, the invention provides the preparation method of the acid and alkali resistant modified aluminum oxide heat conduction powder, and the modified aluminum oxide heat conduction powder prepared by the method has good acid and alkali resistant performance and can be used for preparing acid and alkali resistant heat conduction silicon rubber.

The specific technical scheme is as follows:

the preparation method of the acid and alkali resistant modified aluminum oxide heat conducting powder comprises the following steps:

(1) dispersing aluminum hydroxide in water to obtain aluminum hydroxide slurry, adding solid water glass under the conditions of stirring and pressurizing, and stirring until the solid water glass is completely dissolved;

(2) introducing carbon dioxide into the mixture obtained in the step (1), adjusting the pH value of the solution to 7-8, stopping introducing the gas, aging, relieving pressure and discharging;

(3) sequentially filtering, washing, drying, calcining and crushing the slurry obtained in the step (2);

(4) carrying out surface treatment modification on the powder obtained in the step (3) by using a composite surface treating agent to obtain the acid and alkali resistant modified aluminum oxide heat conducting powder;

the composite surface treating agent is a compound of silane and long-chain fatty acid; the silane is selected from one or more of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and hydrolysis polycondensate of ethyl orthosilicate (such as silicon-28, silicon-40, etc.); the long-chain fatty acid is selected from one or more of oleic acid, stearic acid, lauric acid and palmitic acid.

In some of these embodiments, the aluminum hydroxide slurry has an aluminum hydroxide content of 600g/L to 1200 g/L.

In some of these examples, the aluminum hydroxide slurry is warmed to 50-80 ℃ prior to adding the solid water glass.

In some embodiments, the conditions of stirring and pressurizing of step (1) comprise: the stirring speed is 900-1500r/min, and the pressure is increased to 2-3 atmospheric pressures.

In some embodiments, the solid water glass is added in an amount of 10-60% by mass of the aluminum hydroxide.

In some embodiments, the solid water glass is added in an amount of 10-40% by mass of the aluminum hydroxide.

In some of these embodiments, the solid water glass has a modulus of 1 to 3.

In some of these embodiments, the aging time is from 2 to 4 hours.

In some of these embodiments, the calcination is at a temperature of 1100 ℃ to 1300 ℃ for a time of 4 to 8 hours.

In some of these embodiments, the mass ratio of the silane to the long chain fatty acid is 1: 0.25-4.

In some of these embodiments, the mass ratio of the silane to the long chain fatty acid is 1: 0.25-2.

In some embodiments, the composite surface treatment agent is a compound of ethyl orthosilicate and stearic acid in a mass ratio of 1: 0.8-1.2; or the composite surface treating agent is a compound of vinyl trimethoxy silane and monthly silicic acid in a mass ratio of 1: 1.8-2.2; or the composite surface treating agent is a compound of silicon-40 and oleic acid in a mass ratio of 1: 0.25-0.3.

In some embodiments, the addition amount of the composite surface treatment agent is 0.5-5% of the mass of the powder obtained in the step (3).

In some embodiments, the addition amount of the composite surface treatment agent is 1.5-2.5% of the mass of the powder obtained in the step (3).

In some of these embodiments, the conditions of the surface treatment modification include: the stirring speed is 3000-.

The invention also provides acid and alkali resistant modified aluminum oxide heat conducting powder.

The specific technical scheme is as follows:

the acid and alkali resistant modified alumina heat conducting powder is prepared by the preparation method of the acid and alkali resistant modified alumina heat conducting powder.

The invention also provides acid and alkali resistant heat-conducting silicone rubber.

The specific technical scheme is as follows:

the acid and alkali resistant heat-conducting silicone rubber comprises a component A and a component B in a mass ratio of 1:1, wherein the component A comprises the following raw material components:

100 parts by weight of double-end vinyl silicone oil,

50-200 parts by weight of the acid and alkali resistant modified aluminum oxide heat conducting powder,

5-20ppm of catalyst;

the component B comprises the following raw material components in parts by weight:

in some of these embodiments, the a component comprises the following raw material components:

100 parts by weight of double-end vinyl silicone oil,

100 portions and 180 portions of the acid and alkali resistant modified aluminum oxide heat conducting powder,

8-12ppm of catalyst;

the component B comprises the following raw material components in parts by weight:

in some of these embodiments, the viscosity of the double-ended vinyl silicone oil at 25 ℃ is 100-10000 mPas.

In some of these embodiments, the viscosity of the double-ended vinyl silicone oil at 25 ℃ is 300-1000 mPas.

In some of the embodiments, the hydrogen content of the terminal side hydrogen-containing silicone oil is 0.05 to 1%.

In some of the embodiments, the hydrogen content of the terminal side hydrogen-containing silicone oil is 0.1 to 0.5%.

In some of these embodiments, the catalyst is a platinum catalyst.

In some of these embodiments, the inhibitor is an alkynol inhibitor.

The invention also provides a preparation method of the acid and alkali resistant heat-conducting silicone rubber.

The specific technical scheme is as follows:

the preparation method of the acid and alkali resistant heat-conducting silicone rubber comprises the following steps:

preparation of component A: uniformly mixing the double-end vinyl silicone oil, the acid-base resistant modified alumina heat-conducting powder and the catalyst to obtain the catalyst;

preparation of the component B: and uniformly mixing the double-end vinyl silicone oil, the acid-base resistant modified aluminum oxide heat conduction powder, the end-side hydrogen-containing silicone oil and the inhibitor to obtain the heat conduction material.

Compared with the prior art, the invention has the following beneficial effects:

in the preparation process of the aluminum oxide, the outer surface of the slurry of the aluminum oxide is coated with a protective layer by using water glass, and the aluminum oxide is anchored by using a filter pressing and sintering mode, so that the aluminum oxide has good acid and alkali resistance; the composite surface treating agent compounded by specific silane and long-chain fatty acid is used for further surface modification treatment of the aluminum oxide coated with the protective layer, a specific organic layer is further modified while the surface of the aluminum oxide powder is further coated, the silane coating layer and the organic layer effectively prevent the corrosion of acid-base liquid to the aluminum oxide powder, the acid-base resistance of the modified aluminum oxide can be further improved, the polarity of the organic layer is low, the compatibility with silicone oil is good, the wettability of the silicone oil to the aluminum oxide powder can be improved, the addition amount of the powder can be further improved, and the viscosity of the obtained heat-conducting silicone rubber is reduced. According to the invention, the acid and alkali resistant modified alumina is obtained by coating and modifying the alumina which is not acid and alkali resistant, and when the acid and alkali resistant modified alumina is used for preparing the heat-conducting silicone rubber, the compatibility of the alumina and the silicone rubber can be improved, and the problem of long-term acid and alkali resistance of the heat-conducting silicone rubber is solved.

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, article, or device that comprises a list of steps is not limited to only those steps or modules listed, but may alternatively include other steps not listed or inherent to such process, method, article, or device.

The "plurality" referred to in the present invention means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

The following are specific examples.

The viscosities stated in the examples below all refer to the viscosity at a temperature of 25 ℃.

The aluminum hydroxide in the following examples and comparative examples means commercial industrial-grade aluminum hydroxide purified from impurities by the following conventional method: dissolving commercial industrial-grade aluminum hydroxide with a surfactant, a water-soluble acid and deionized water, and purifying the solution through steps of acid washing, adsorption by anion adsorption resin and cation adsorption resin, suction filtration and the like until the purity of the aluminum hydroxide is more than 99.5 percent, or directly purchasing the aluminum hydroxide with the purity of 99.5 percent.

Example 1

The embodiment provides an acid and alkali resistant modified alumina heat conducting powder, and the preparation method comprises the following steps:

1. taking aluminum hydroxide, stirring and dispersing the aluminum hydroxide in deionized water to obtain slurry with the aluminum hydroxide content of 1000g/L, heating to 80 ℃, adding solid sodium silicate with the modulus of 2 accounting for 20 mass percent of the aluminum hydroxide under the conditions of stirring speed of 1200r/min and pressurization to 3 atmospheric pressures, and fully stirring to completely dissolve the sodium silicate.

2. And introducing carbon dioxide into the system while stirring, adjusting the pH of the solution to 7, stopping introducing the gas, aging for 4 hours, relieving pressure and discharging.

3. The slurry was filter-pressed, washed with deionized water, dried, calcined at 1300 ℃ for 6 hours, and the resulting powder was pulverized and sieved with a 400 mesh sieve.

4. And adding the sieved powder into a surface treatment barrel, starting high-speed stirring at 3500r/min, controlling the temperature of the powder to be 80 ℃, adding 1% of tetraethoxysilane and 1% of stearic acid in terms of the mass of the powder to perform surface treatment modification, and continuously stirring for 90min to obtain the acid-base-resistant modified alumina heat-conducting powder.

The acid and alkali resistant modified alumina heat-conducting powder prepared by the embodiment is used for preparing heat-conducting silicone rubber, and the preparation method comprises the following steps:

the component A comprises: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 100 parts by weight of acid-base resistant modified alumina heat-conducting powder and Kaersit platinum catalyst with the concentration of 12ppm in the system are vacuumized to be below 0.01MPa in a planetary machine, and are stirred and mixed uniformly at the stirring speed of 20r/min to obtain the catalyst.

And B component: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 110 parts by weight of acid-base-resistant modified alumina heat-conducting powder, 12 parts by weight of end-side hydrogen-containing silicone oil (hydrogen-terminated polydimethylmethylhydrosiloxane) with the hydrogen content of 0.35 percent and 0.2 part by weight of ethynl cyclohexanol are pumped in a planetary machine to be vacuum-pumped to be below 0.01MPa, and are uniformly stirred at the stirring speed of 20r/min, so that the catalyst is obtained.

A, B components are uniformly mixed according to the mass ratio of 1:1, after defoaming, the mixture is heated at 120 ℃ for half an hour for curing to prepare a standard test piece, and the performance of the standard test piece after being respectively soaked in 10% NaOH and 10% hydrochloric acid solution and accelerated aging at 60 ℃ for 24 hours are tested.

Example 2

The embodiment provides an acid and alkali resistant modified alumina heat conducting powder, and the preparation method comprises the following steps:

1. taking aluminum hydroxide, stirring and dispersing the aluminum hydroxide in deionized water to obtain slurry with the aluminum hydroxide content of 1200g/L, heating to 80 ℃, adding solid sodium silicate with the modulus of 1 accounting for 40 mass percent of the aluminum hydroxide under the conditions of stirring speed of 1500r/min and pressurization to 3 atmospheric pressure, and fully stirring to completely dissolve the sodium silicate.

2. And introducing carbon dioxide into the system while stirring, adjusting the pH of the solution to 7, stopping introducing the gas, aging for 3 hours, relieving pressure and discharging.

3. The slurry was filter-pressed, washed with deionized water, dried, calcined at 1300 ℃ for 8 hours, the resulting powder was pulverized and sieved with a 400 mesh sieve.

4. Adding the sieved powder into a surface treatment barrel, starting 5000r/min high-speed stirring, controlling the temperature of the powder to be 100 ℃, adding 0.5 percent of vinyl trimethoxy silane and 1 percent of monthly silicic acid by mass of the powder for surface treatment and modification, and continuously stirring for 90min to obtain the acid-alkali-resistant modified alumina heat-conducting powder.

The acid and alkali resistant modified alumina heat-conducting powder prepared by the embodiment is used for preparing heat-conducting silicone rubber, and the preparation method comprises the following steps:

the component A comprises: 100 parts by weight of double-end vinyl silicone oil with 500 mPas viscosity, 150 parts by weight of acid-base resistant modified alumina heat-conducting powder and 10ppm Kaersit platinum catalyst in the system are vacuumized to be below 0.01MPa in a planetary machine, and are stirred and mixed uniformly at a stirring speed of 20r/min to obtain the catalyst.

And B component: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 500 mPas, 180 parts by weight of acid-base-resistant alumina heat-conducting powder, 12 parts by weight of end-side hydrogen-containing silicone oil with the hydrogen content of 0.5 percent and 0.2 part by weight of ethynl cyclohexanol are pumped in a planetary machine to be vacuum-pumped to be below 0.01MPa, and are stirred and mixed uniformly at the stirring speed of 20r/min, so that the catalyst is obtained.

A, B components are uniformly mixed according to the mass ratio of 1:1, after defoaming, the mixture is heated at 120 ℃ for half an hour for curing to prepare a standard test piece, and the performance of the standard test piece after being respectively soaked in 10% NaOH and 10% hydrochloric acid solution and accelerated aging at 60 ℃ for 24 hours are tested.

Example 3

The embodiment provides an acid and alkali resistant modified alumina heat conducting powder, and the preparation method comprises the following steps:

1. taking aluminum hydroxide, stirring and dispersing the aluminum hydroxide in deionized water to obtain slurry with the aluminum hydroxide content of 600g/L, heating to 60 ℃, adding solid sodium silicate with the modulus of 2, wherein the solid sodium silicate accounts for 10 mass percent of the aluminum hydroxide under the conditions of stirring speed of 1000r/min and pressurization to 2 atmospheric pressure, and fully stirring to completely dissolve the sodium silicate.

2. And introducing carbon dioxide into the system while stirring, adjusting the pH of the solution to 8, stopping introducing the gas, aging for 4 hours, relieving pressure and discharging.

3. The slurry was filter-pressed, washed with deionized water, dried, calcined at 1300 ℃ for 8 hours, and the resulting powder was pulverized and sieved with a 400 mesh sieve.

4. Adding the sieved powder into a surface treatment barrel, starting high-speed stirring at 3000r/min, controlling the temperature of the powder to be 60 ℃, adding 2% of silicon-40 and 0.5% of oleic acid by mass of the powder for surface treatment and modification, and continuously stirring for 90min to obtain the acid-alkali-resistant modified alumina heat-conducting powder.

The acid and alkali resistant modified alumina heat-conducting powder prepared by the embodiment is used for preparing heat-conducting silicone rubber, and the preparation method comprises the following steps:

the component A comprises: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 300 mPas, 180 parts by weight of acid-base-resistant modified alumina heat-conducting powder and a Kaersit platinum catalyst with the concentration of 8ppm in the system are vacuumized in a planetary machine to be below 0.01MPa, and are stirred and mixed uniformly at the stirring speed of 20r/min to obtain the catalyst.

And B component: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 300 mPas, 220 parts by weight of acid-base-resistant modified alumina heat-conducting powder, 70 parts by weight of end-side hydrogen-containing silicone oil with the hydrogen content of 0.1 percent and 0.2 part by weight of ethynl cyclohexanol are pumped in a planetary machine to be vacuum-pumped to be below 0.01MPa, and are stirred and mixed uniformly at the stirring speed of 20r/min to obtain the catalyst.

A, B components are uniformly mixed according to the mass ratio of 1:1, after defoaming, the mixture is heated at 120 ℃ for half an hour for curing to prepare a standard test piece, and the performance of the standard test piece after being respectively soaked in 10% NaOH and 10% hydrochloric acid solution and accelerated aging at 60 ℃ for 24 hours are tested.

Comparative example 1

In the comparative example, the commercially available common aluminum oxide heat-conducting powder is used for preparing the heat-conducting silicone rubber, and the preparation method comprises the following steps:

the component A comprises: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 100 parts by weight of common aluminum oxide heat-conducting powder sold in the market and Kaersit platinum catalyst with the concentration of 12ppm in the system are vacuumized to be below 0.01MPa in a planetary machine, and are stirred and mixed uniformly at the stirring speed of 20r/min to obtain the catalyst.

And B component: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 110 parts by weight of common aluminum oxide heat conducting powder sold in the market, 12 parts by weight of end-side hydrogen-containing silicone oil with the hydrogen content of 0.35 percent and 0.2 part by weight of ethynl cyclohexanol are vacuumized in a planetary machine to be below 0.01MPa, and are stirred and mixed uniformly at the stirring speed of 20r/min to obtain the catalyst.

A, B components are uniformly mixed according to the mass ratio of 1:1, after defoaming, the mixture is heated at 120 ℃ for half an hour for curing to prepare a standard test piece, and the performance of the standard test piece after being respectively soaked in 10% NaOH and 10% hydrochloric acid solution and accelerated aging at 60 ℃ for 24 hours are tested.

Comparative example 2

The comparative example provides a modified alumina heat-conducting powder, and the preparation method comprises the following steps:

1. taking aluminum hydroxide, stirring and dispersing the aluminum hydroxide in deionized water to obtain slurry with the aluminum hydroxide content of 1000g/L, heating to 80 ℃, adding solid sodium silicate with the modulus of 2 accounting for 20 mass percent of the aluminum hydroxide under the conditions of stirring speed of 1200r/min and pressurization to 3 atmospheric pressures, and fully stirring to completely dissolve the sodium silicate.

2. And introducing carbon dioxide into the system while stirring, adjusting the pH of the solution to 7, stopping introducing the gas, aging for 4 hours, relieving pressure and discharging.

3. And (3) carrying out filter pressing on the slurry, washing the slurry by deionized water, drying the slurry, calcining the slurry for 6 hours at 1300 ℃, crushing the obtained powder, and screening the powder by using a 400-mesh screen to obtain the modified alumina heat-conducting powder.

The modified alumina heat-conducting powder prepared by the comparative example is used for preparing heat-conducting silicone rubber, and the preparation method comprises the following steps:

the component A comprises: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 100 parts by weight of modified alumina heat-conducting powder and Kaersit platinum catalyst with the concentration of 12ppm in the system are vacuumized to be below 0.01MPa in a planetary machine, and are stirred and mixed uniformly at the stirring speed of 20r/min to obtain the catalyst.

And B component: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 110 parts by weight of modified alumina heat-conducting powder, 12 parts by weight of end-side hydrogen-containing silicone oil (hydrogen-terminated polydimethylmethylhydrogensiloxane) with the hydrogen content of 0.35 percent and 0.2 part by weight of ethynl cyclohexanol are pumped in a planetary machine to be vacuum-pumped to be below 0.01MPa, and are stirred and mixed uniformly at the stirring speed of 20r/min, so that the catalyst is obtained.

A, B components are uniformly mixed according to the mass ratio of 1:1, after defoaming, the mixture is heated at 120 ℃ for half an hour for curing to prepare a standard test piece, and the performance of the standard test piece after being respectively soaked in 10% NaOH and 10% hydrochloric acid solution and accelerated aging at 60 ℃ for 24 hours are tested.

Comparative example 3

The comparative example provides a modified alumina heat-conducting powder, and the preparation method comprises the following steps:

1. taking aluminum hydroxide, stirring and dispersing the aluminum hydroxide in deionized water to obtain slurry with the aluminum hydroxide content of 1000g/L, heating to 80 ℃, adding solid sodium silicate with the modulus of 2 accounting for 20 mass percent of the aluminum hydroxide under the conditions of stirring speed of 1200r/min and pressurization to 3 atmospheric pressures, and fully stirring to completely dissolve the sodium silicate.

2. And introducing carbon dioxide into the system while stirring, adjusting the pH of the solution to 7, stopping introducing the gas, aging for 4 hours, relieving pressure and discharging.

3. The slurry was filter-pressed, washed with deionized water, dried, calcined at 1300 ℃ for 6 hours, and the resulting powder was pulverized and sieved with a 400 mesh sieve.

4. And adding the sieved powder into a surface treatment barrel, starting high-speed stirring at 3500r/min, controlling the temperature of the powder to be 80 ℃, adding 2% of tetraethoxysilane based on the mass of the powder to perform surface treatment modification, and continuously stirring for 90min to obtain the modified aluminum oxide heat-conducting powder.

The modified alumina heat-conducting powder prepared by the comparative example is used for preparing heat-conducting silicone rubber, and the preparation method comprises the following steps:

the component A comprises: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 100 parts by weight of modified alumina heat-conducting powder and Kaersit platinum catalyst with the concentration of 12ppm in the system are vacuumized to be below 0.01MPa in a planetary machine, and are stirred and mixed uniformly at the stirring speed of 20r/min to obtain the catalyst.

And B component: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 110 parts by weight of modified alumina heat-conducting powder, 12 parts by weight of end-side hydrogen-containing silicone oil (hydrogen-terminated polydimethylmethylhydrogensiloxane) with the hydrogen content of 0.35 percent and 0.2 part by weight of ethynl cyclohexanol are pumped in a planetary machine to be vacuum-pumped to be below 0.01MPa, and are stirred and mixed uniformly at the stirring speed of 20r/min, so that the catalyst is obtained.

A, B components are uniformly mixed according to the mass ratio of 1:1, after defoaming, the mixture is heated at 120 ℃ for half an hour for curing to prepare a standard test piece, and the performance of the standard test piece after being respectively soaked in 10% NaOH and 10% hydrochloric acid solution and accelerated aging at 60 ℃ for 24 hours are tested.

Comparative example 4

The comparative example provides a modified alumina heat-conducting powder, and the preparation method comprises the following steps:

1. taking aluminum hydroxide, stirring and dispersing the aluminum hydroxide in deionized water to obtain slurry with the aluminum hydroxide content of 1000g/L, heating to 80 ℃, adding solid sodium silicate with the modulus of 2 accounting for 20 mass percent of the aluminum hydroxide under the conditions of stirring speed of 1200r/min and pressurization to 3 atmospheric pressures, and fully stirring to completely dissolve the sodium silicate.

2. And introducing carbon dioxide into the system while stirring, adjusting the pH of the solution to 7, stopping introducing the gas, aging for 4 hours, relieving pressure and discharging.

3. The slurry was filter-pressed, washed with deionized water, dried, calcined at 1300 ℃ for 6 hours, and the resulting powder was pulverized and sieved with a 400 mesh sieve.

4. And adding the sieved powder into a surface treatment barrel, starting high-speed stirring at 3500r/min, controlling the temperature of the powder to be 80 ℃, adding stearic acid accounting for 2 percent of the mass of the powder for surface treatment and modification, and continuously stirring for 90min to obtain the modified aluminum oxide heat-conducting powder.

The modified alumina heat-conducting powder prepared by the comparative example is used for preparing heat-conducting silicone rubber, and the preparation method comprises the following steps:

the component A comprises: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 100 parts by weight of modified alumina heat-conducting powder and Kaersit platinum catalyst with the concentration of 12ppm in the system are vacuumized to be below 0.01MPa in a planetary machine, and are stirred and mixed uniformly at the stirring speed of 20r/min to obtain the catalyst.

And B component: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 110 parts by weight of modified alumina heat-conducting powder, 12 parts by weight of end-side hydrogen-containing silicone oil (hydrogen-terminated polydimethylmethylhydrogensiloxane) with the hydrogen content of 0.35 percent and 0.2 part by weight of ethynl cyclohexanol are pumped in a planetary machine to be vacuum-pumped to be below 0.01MPa, and are stirred and mixed uniformly at the stirring speed of 20r/min, so that the catalyst is obtained.

A, B components are uniformly mixed according to the mass ratio of 1:1, after defoaming, the mixture is heated at 120 ℃ for half an hour for curing to prepare a standard test piece, and the performance of the standard test piece after being respectively soaked in 10% NaOH and 10% hydrochloric acid solution and accelerated aging at 60 ℃ for 24 hours are tested.

Comparative example 5

The comparative example provides a modified alumina heat-conducting powder, and the preparation method comprises the following steps:

adding commercially available common aluminum oxide heat conducting powder into a surface treatment barrel, starting high-speed stirring at 3500r/min, controlling the temperature of the powder to be 80 ℃, adding 1% of tetraethoxysilane and 1% of stearic acid based on the mass of the powder for surface treatment and modification, and continuously stirring for 90min to obtain the modified aluminum oxide heat conducting powder.

The modified alumina heat-conducting powder prepared by the comparative example is used for preparing heat-conducting silicone rubber, and the preparation method comprises the following steps:

the component A comprises: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 100 parts by weight of modified alumina heat-conducting powder and Kaersit platinum catalyst with the concentration of 12ppm in the system are vacuumized to be below 0.01MPa in a planetary machine, and are stirred and mixed uniformly at the stirring speed of 20r/min to obtain the catalyst.

And B component: 100 parts by weight of double-end vinyl silicone oil with the viscosity of 1000 mPas, 110 parts by weight of modified alumina heat-conducting powder, 12 parts by weight of end-side hydrogen-containing silicone oil (hydrogen-terminated polydimethylmethylhydrogensiloxane) with the hydrogen content of 0.35 percent and 0.2 part by weight of ethynl cyclohexanol are pumped in a planetary machine to be vacuum-pumped to be below 0.01MPa, and are stirred and mixed uniformly at the stirring speed of 20r/min, so that the catalyst is obtained.

A, B components are uniformly mixed according to the mass ratio of 1:1, after defoaming, the mixture is heated at 120 ℃ for half an hour for curing to prepare a standard test piece, and the performance of the standard test piece after being respectively soaked in 10% NaOH and 10% hydrochloric acid solution and accelerated aging at 60 ℃ for 24 hours are tested.

The heat-conductive silicone rubbers prepared in the above examples 1-3 and comparative examples 1-5 were subjected to performance testing in accordance with GB/T528-2009, and the test results of the heat-conductive silicone rubbers prepared in examples 1-3 and comparative examples 1-5 are shown in Table 1 below.

TABLE 1

As can be seen from the results of table 1: the surface coating treatment of the alumina by the water glass and the surface modification treatment of the combination of the silane and the long-chain fatty acid can synergistically improve the acid and alkali resistance of the heat-conducting silicon rubber, reduce the viscosity of the heat-conducting silicon rubber and improve the tensile strength of the heat-conducting silicon rubber. The heat-conducting silicone rubber prepared by the acid-alkali-resistant modified aluminum oxide has good acid-alkali resistance and lower viscosity.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.