CN115353856A

CN115353856A - Low-viscosity high-strength organic silicon pouring sealant and preparation method thereof

Info

Publication number: CN115353856A
Application number: CN202211171249.XA
Authority: CN
Inventors: 李华; 罗裕锋; 唐浩; 张浩清; 李中鹏
Original assignee: Shenzhen Union Tenda Technology Co ltd
Current assignee: Shenzhen Union Tenda Technology Co ltd
Priority date: 2022-09-24
Filing date: 2022-09-24
Publication date: 2022-11-18

Abstract

The application relates to the field of organic silicon pouring sealant, and particularly discloses a low-viscosity high-strength bi-component organic silicon pouring sealant and a preparation method thereof. The low-viscosity high-strength double-component organic silicon pouring sealant is formed by mixing a component A and a component B according to the mass ratio of 1, wherein the component A comprises 85 parts of a matrix, 9.8-12.8 parts of vinyl polysiloxane, 2-5 parts of polydimethylsiloxane and 0.05-0.2 part of platinum catalyst, the component B comprises 85 parts of the matrix, 5.5-8.7 parts of vinyl polysiloxane, 1-2 parts of polydimethylsiloxane, 5-8 parts of hydrogen-containing silicone oil, 0.005-0.08 part of inhibitor and 0-0.4 part of carbon black color paste, and the hydrogen-containing silicone oil comprises hydrogen-containing silicone oil at the end side. The low-viscosity high-strength two-component organic silicon pouring sealant can be used for pouring and sealing various electronic components, and has the advantages of low viscosity, high strength, excellent component protection effect, good heat-conducting property and the like; in addition, the preparation method adopts common equipment and simple process, and can be used for large-scale production.

Description

Low-viscosity high-strength organic silicon pouring sealant and preparation method thereof

Technical Field

The application relates to the technical field of organic silicon pouring sealants, in particular to a low-viscosity high-strength organic silicon pouring sealant and a preparation method thereof.

Background

Along with the development of the times, electronic technology products are integrated into the lives of people, new requirements are brought gradually, the potting adhesive is usually flowable liquid before curing, components can be coated into a whole due to good flowability, and the potting adhesive can play the roles of sealing, moisture and water proofing, insulating, heat conducting, rust and corrosion preventing, fixing and protecting and the like after curing. Therefore, the pouring sealant is widely applied to the protection of electronic components.

In the related technology, the organic silicon pouring sealant comprises vinyl silicone oil, vinyl silicone resin, cage octaphenyl silsesquioxane, an inhibitor, platinum water and other components, and under the action of the platinum water and the inhibitor, the vinyl silicone oil and the vinyl silicone resin can be combined with hydrogen-containing silicone oil through hydrosilylation reaction, so that the organic silicon pouring sealant has higher refractive index, excellent mechanical strength and thermal stability after being cured.

The two-component organic silicon pouring sealant comprises a component A and a component B, wherein the two components react fully according to a proper proportion to form an elastomer, so that the two-component organic silicon pouring sealant gradually becomes a research focus. In the related technology, the component A comprises alpha, omega-dihydroxy polydimethylsiloxane, dimethyl silicon oil, RTV base glue, silicon micropowder and toner, the component B comprises dimethyl diethoxy silane, dimethyl silicon oil, 3-aminopropyl triethoxysilane, vinyl triethoxysilane and dibutyltin dilaurate, after the component A and the component B are mixed, active groups in silica gel are condensed to separate small molecules for crosslinking curing under the catalysis of moisture in the air, and then the organic silicon pouring sealant with excellent mechanical properties can be prepared.

Disclosure of Invention

In order to solve the problems that the silicone curing process shrinks and releases byproducts, and the prepared silicone pouring sealant has poor application performance, the application provides a low-viscosity and high-strength silicone pouring sealant and a preparation method thereof.

In a first aspect, the application provides a low-viscosity and high-strength silicone pouring sealant, which adopts the following technical scheme:

the organic silicon pouring sealant with low viscosity and high strength is formed by mixing a component A and a component B according to the mass ratio of 1; the hydrogen-containing silicone oil includes an end-side hydrogen-containing silicone oil.

By adopting the technical scheme, the vinyl siloxane has a silicon-oxygen bond and an ethylene double bond, the polydimethylsiloxane and the hydrogen-containing silicone oil also have a silicon-oxygen bond, the silicon-oxygen bond of the hydrogen-containing silicone oil and the carbon-carbon double bond of the ethylene rapidly perform addition reaction to form a cross-linked net structure, after the component A and the component B are mixed, the platinum catalyst accelerates the cross-linking speed of the silicon-oxygen bond and the ethylene, the silicone pouring sealant is rapidly cured to form the silicone pouring sealant, and no by-product is generated in the curing process.

In order to avoid the performance reduction of the pouring sealant caused by local over-crosslinking due to the excessively high catalytic speed of the platinum catalyst, an inhibitor is added into the component B, and the reaction speed is adjusted by the inhibitor to prevent the reaction from being excessively violent, so that the finally prepared colloid has a good application effect.

The silicone oil containing hydrogen at the end side has higher content of silicon-oxygen bonds, and can be quickly crosslinked with vinyl to form the pouring sealant with tearing performance and tensile performance.

The organic silicon pouring sealant prepared by the application is an addition type pouring sealant, and compared with a condensation organic silicon pouring sealant, the pouring sealant prepared by the application has no micromolecule by-product in the vulcanization process, the cross-linking structure is easy to control, and the shrinkage rate of a vulcanized product is small; the product has excellent processing performance, and can be vulcanized at normal temperature and under heating condition. And can be quickly vulcanized deeply, and the processing performance of the product is good.

Preferably, the viscosity of the vinyl polysiloxane is 100cps.

By adopting the technical scheme, the viscosity of the vinyl polysiloxane is low, and the viscosity of the finally prepared component A and component B is also low.

Preferably, the matrix comprises the following components in parts by mass: 51-76 parts of vinyl polysiloxane, 2-3 parts of silane treating agent, 4-10 parts of reinforcing agent and 93.5-100 parts of heat conducting filler, wherein the vinyl polysiloxane comprises 40-52 parts of vinyl polysiloxane with the viscosity of 100cps and 11-24 parts of vinyl polysiloxane with the viscosity of 10000 cps.

By adopting the technical scheme, the matrix comprises the reinforcing agent and the silane treating agent, the reinforcing agent interacts with the vinyl polysiloxane to generate a strong chemical bond, when the vinyl polysiloxane and the reinforcing agent are mixed to generate the pouring sealant, the pouring sealant is stretched, and the chemical bond slides along the surface of the reinforcing agent, so that the external impact is absorbed, and the tearing strength is improved; in addition, the chemical bond slides, so that the surface of the pouring sealant is uniformly stressed, and the tensile strength of the pouring sealant is improved.

The addition amount of the reinforcing agent is controlled to be 4-10 parts, 40-52 parts of 100cps vinyl polysiloxane and 11-24 parts of 10000cps vinyl polysiloxane, the prepared matrix is combined with polydimethylsiloxane, hydrogen-containing silicone oil and other components, and the formed pouring sealant has higher tensile strength and tearing strength, especially the tearing strength which can reach 14-25KN/m.

Finally, vinyl polysiloxane with the viscosity of 100cps and 10000cps is used together, so that the overall viscosity is adjusted, and the lower overall viscosity of the prepared pouring sealant is ensured; moreover, 10000cps of vinyl polysiloxane can improve the tensile strength of the pouring sealant. If the viscosity of the vinyl polysiloxane is less than 100cps, the finally prepared pouring sealant is easy to separate out oil and has poor reliability. When the vinyl polysiloxane is higher than 10000cps, the prepared pouring sealant has high overall viscosity and poor flowability and pouring effect.

Preferably, the vinyl polysiloxane has a vinyl content of 0.12% to 1.2%.

More preferably, the vinyl polysiloxane having a viscosity of 100cps has a vinyl content of 1.2% and the vinyl polysiloxane having a viscosity of 10000cps has a vinyl content of 0.12%.

By adopting the technical scheme, the high vinyl content means low viscosity, and when the vinyl content is higher than 1.2%, the prepared matrix contains more volatile micromolecule groups, so that the aging performance of the finally prepared pouring sealant is influenced, and the product becomes brittle, and the tensile strength and the tear resistance are reduced. Repeated experiments show that the tensile strength and tear strength of the prepared pouring sealant are highest when the vinyl content of the vinyl polysiloxane with the viscosity of 100cps is 1.2 percent and the vinyl content of the vinyl polysiloxane with the viscosity of 10000cps is 0.12 percent.

Preferably, the reinforcing agent comprises at least one of white carbon black and vinyl silicon resin, and the white carbon black accounts for 5-10 parts by mass.

Preferably, the particle size of the white carbon black is 12-20nm.

Preferably, the vinyl silicone resin has a viscosity of 11000cps to 22000cps and a vinyl content of 1.08% to 1.2%.

By adopting the technical scheme, when the white carbon black is combined with vinyl polysiloxane and polydimethylsiloxane, the generated colloid system has low viscosity and shows good fluidity. More importantly, when the addition amount of the white carbon black is 5-10 parts, the addition amount is converted into 3% -6% of the total mass of the matrix, and the tensile strength and the tearing strength of the prepared pouring sealant are effectively improved.

Because the surface of the white carbon black has active silicon hydroxyl, adsorbed water and an acid area on the surface of the white carbon black caused by a preparation process, the white carbon black is hydrophilic, is difficult to infiltrate and disperse in an organic phase, and cannot be well compatible with a polymer in a rubber vulcanization system, thereby reducing the vulcanization efficiency and the reinforcement performance. Therefore, silane treating agent is usually adopted to modify the white carbon black, so that the modified white carbon black has the advantages of improving the surface activity, improving the dispersibility and compatibility in an organic phase and improving the reinforcing effect of the white carbon black.

The viscosity of the vinyl silicon resin is controlled to be 11000-22000cps, so that the viscosity of the system is adjusted, and the phenomenon that the prepared matrix is too high to be applied is ensured. The content of the vinyl is limited to be 1.0-1.2%, and the vinyl content is kept close to that of the vinyl polysiloxane with the viscosity of 100cps, so that the system is uniform and stable.

Preferably, the heat conducting filler comprises at least one of alumina, aluminum hydroxide and silica powder, and the mass ratio of the alumina: aluminum hydroxide: fine silica powder = (1-2): (3-4): (1-2).

Preferably, the average particle diameter of the thermally conductive filler is 1 to 40um, preferably 5 to 20um.

By adopting the technical scheme, the heat-conducting filler with the particle size of 5-20 microns is fine and smooth, the filling effect is good, the prepared pouring sealant has excellent mechanical property, and if the particle size of the heat-conducting filler is smaller than 5 microns, the prepared pouring sealant has high viscosity and poor product fluidity; if the particle size of the heat-conducting filler exceeds 20um, the tear resistance and tensile strength of the prepared pouring sealant are not obviously improved.

Preferably, the silane treatment agent is at least one of methyltrimethoxysilane, vinyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, 3- (2, 3-glycidoxy) propyltrimethylsilane, n-octyltriethoxysilane, and hexamethyldisilazane.

Preferably, the silane treatment agent is hexamethyldisilazane and dodecyltrimethoxysilane.

By adopting the technical scheme, experiments prove that hexamethyldisilazane and dodecyl trimethoxy silane are excellent modifiers for treating white carbon black, reinforcing property of reinforcing agent treated by silane treating agent is stronger, and tensile strength and tear resistance of the prepared pouring sealant are higher.

Preferably, the hydrogen-containing silicone oil also comprises terminal hydrogen-containing silicone oil; the mass ratio of the end hydrogen-containing silicone oil to the end hydrogen-containing silicone oil is 1 (2-3).

The hydrogen content of the end side hydrogen-containing silicone oil is 0.8-1%, the viscosity is 40-70cps, and the hydrogen content of the end side hydrogen-containing silicone oil is 0.05-0.1%, and the viscosity is 20-40cps.

By adopting the technical scheme, the end hydrogen-containing silicone oil and the vinyl polysiloxane are mutually combined, the chain segment of the vinyl polysiloxane is increased, after the end hydrogen-containing silicone oil is continuously added, the end hydrogen-containing silicone oil and the vinyl polysiloxane are combined to form a cross-linked network structure, and the structure enables the formed pouring sealant to have certain strength and hardness.

The influence of the hydrogen content of the hydrogen-containing silicone oil on a finished product is large, when the hydrogen content of the end side hydrogen-containing silicone oil is 0.8% -1%, and the hydrogen content of the end hydrogen-containing silicone oil is 0.05% -0.1%, the prepared pouring sealant has a perfect surface and does not generate air holes, if the hydrogen content is high, the system reaction starts quickly, but the reaction is severe, and finally the caused pouring sealant is easy to generate air holes to influence the use.

Preferably, the platinum catalyst is any one or two combinations of a divinyl tetramethyl disiloxane platinum complex, a divinyl octamethyl tetrasiloxane platinum complex or a chloroplatinic acid alcohol solution;

preferably, the carbon black color paste is a vinyl carbon black color paste.

Preferably, the inhibitor is one or more of vinyl ring body, ethynyl cyclohexanol and maleic acid ester.

In a second aspect, the application provides a preparation method of a low-viscosity and high-strength organosilicon pouring sealant, which adopts the following technical scheme:

a preparation method of low-viscosity and high-strength organic silicon pouring sealant comprises the following steps: stirring the substrate, the vinyl polysiloxane, the polydimethylsiloxane and the platinum catalyst for 10-20min at the rotating speed of 30-40rpm, vacuumizing, stirring and defoaming for 30min after stirring is finished to obtain a component A, and testing the viscosity of the component A;

stirring the matrix, vinyl polysiloxane, polydimethylsiloxane, hydrogen-containing silicone oil, inhibitor and carbon black color paste at the rotating speed of 30-40rpm for 10-20min, vacuumizing, stirring and defoaming for 30min after stirring to obtain a component B, and testing the viscosity of the component B; and (3) uniformly mixing and stirring the component A and the component B according to the mass ratio of 1.

By adopting the technical scheme, the organic silicon pouring sealant comprises the component A and the component B, under the action of the platinum catalyst, the vinyl polysiloxane and the hydrogen-containing silicone oil are subjected to addition reaction to form a cross-linked net-shaped structure, no by-product is generated in the curing process, and the finally prepared addition type organic silicon pouring sealant is low in viscosity, good in flowability, high in tensile strength and tear strength, capable of being applied to most components and good in wrapping effect.

In the preparation process, a kneader and other equipment are not needed, the whole preparation process is simple, the required time is short, and the prepared component A and the component B can be cured after being mixed without redundant operation steps.

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

1. the vinyl polysiloxane with the viscosity of 100cps and the vinyl polysiloxane with the viscosity of 10000cps are adopted, two vinyl polysiloxanes with different viscosities are combined with the reinforcing agent to generate a strong chemical bond, the other part of vinyl polysiloxane and hydrogen-containing silicone oil are subjected to addition reaction to form a cross-linked net structure, the component A and the component B are uniformly mixed and cured under the catalysis of a platinum catalyst, no product is generated in the curing process, and the silica gel is not shrunk in the curing process. The finally formed organic silicon pouring sealant is low in viscosity, high in tensile strength and tear strength, suitable for most of components and good in wrapping effect.

2. When the reinforcing agent is compounded by adopting white carbon black and vinyl silicone resin, the addition amount of the white carbon black is controlled, and when the addition amount of the white carbon black is 3-6% of the total mass of the matrix, the tearing strength and the tensile strength of the prepared organic silicon pouring sealant can reach the highest.

3. The hydrogen-containing silicone oil must comprise the end-side hydrogen-containing silicone oil, so that the end-side hydrogen-containing silicone oil and the vinyl polysiloxane can form a cross-linked network structure after being combined; in addition, the hydrogen content in the terminal hydrogen-containing silicone oil and the terminal hydrogen-containing silicone oil is limited, when the hydrogen content of the terminal hydrogen-containing silicone oil is 0.8-1%, and the hydrogen content of the terminal hydrogen-containing silicone oil is 0.05-0.1%, the compactness of a cross-linked structure formed by the hydrogen-containing silicone oil and the vinyl polysiloxane is strongest, the prepared pouring sealant does not generate air holes, and the viscosity is moderate.

Detailed Description

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

Preparation example

Preparation example 1

Adding 50.5 parts of vinyl polysiloxane with the viscosity of 100cps, 13 parts of vinyl polysiloxane with the viscosity of 10000cps, 3 parts of silane treating agent and 10 parts of reinforcing agent into a stirrer, stirring for 5min at the rotating speed of 500-800rpm, then adding 93.5 parts of heat conducting filler twice, stirring for 30min at the rotating speed of 1000-1200 rpm to prepare a mixture, heating the mixture to 160 ℃, stirring for 3-4 h at the temperature while vacuumizing to obtain a matrix, setting the vacuum degree to be lower than-0.08 MPa, and finally cooling to the normal temperature for later use.

Wherein the vinyl polysiloxane with the viscosity of 100cps has a vinyl content of 1.2%, and the vinyl polysiloxane with the viscosity of 10000cps has a vinyl content of 0.12%; the silane treatment agent is a mixture of hexamethyldisilazane and dodecyl trimethoxy silane in a mass ratio of 6; the reinforcing agent is untreated white carbon black and vinyl silicone resin, and the mass ratio is 8:2, the average particle size of the white carbon black is 15nm, the viscosity of the vinyl silicone resin is 11000cps, and the vinyl content is 1.2 percent; the heat-conducting filler is alumina, aluminum hydroxide and silicon micropowder, and the mass ratio of the alumina to the aluminum hydroxide to the silicon micropowder is 2:3:1, average particle size of 8um.

Preparation example 2

The present preparation example differs from preparation example 1 in that: the vinyl polysiloxane having a viscosity of 100cps has a vinyl content of 1.0%, and the vinyl polysiloxane having a viscosity of 10000cps has a vinyl content of 0.3%.

Preparation example 3

The preparation example differs from preparation example 1 in that: the silane treatment agent is a mixture of hexamethyldisilazane and dodecyl trimethoxy silane in a mass ratio of 3.

Preparation example 4

The present preparation example differs from preparation example 1 in that: the silane treatment agent is a mixture of hexamethyldisilazane and dodecyl trimethoxy silane in a mass ratio of 5.

Preparation example 5

The present preparation example differs from preparation example 1 in that: the silane treating agent is hexamethyldisilazane.

Preparation example 6

The present preparation example differs from preparation example 1 in that: the silane treating agent is dodecyl trimethoxy silane.

Preparation example 7

The present preparation example differs from preparation example 1 in that: the reinforcing agent is untreated white carbon black and vinyl silicone resin, and the mass ratio is 6.

Preparation example 8

The present preparation example differs from preparation example 1 in that: the reinforcing agent is untreated white carbon black and vinyl silicone resin, and the mass ratio is 5.

Preparation example 9

The present preparation example differs from preparation example 1 in that: the reinforcing agent is all untreated white carbon black.

Preparation example 10

The preparation example differs from preparation example 1 in that: the reinforcing agent is all untreated vinyl silicone resin.

Preparation example 11

The present preparation example differs from preparation example 10 in that: the reinforcing agents are all untreated vinyl silicone resin, the viscosity of the vinyl silicone resin is 22000cps, and the vinyl content is 1.08%.

Preparation example 12

The preparation example differs from preparation example 10 in that: the reinforcing agents were all untreated vinyl silicone resin having a viscosity of 15000cps and a vinyl content of 1.1%.

Preparation example 13

The present preparation example differs from preparation example 1 in that: the heat-conducting filler is alumina, aluminum hydroxide and silicon micropowder, and the mass ratio of the alumina to the aluminum hydroxide to the silicon micropowder is 1:3:2, the average particle diameter is 20um.

Preparation example 14

The present preparation example differs from preparation example 1 in that: the heat-conducting filler is alumina, aluminum hydroxide and silicon micropowder, and the mass ratio of the alumina to the aluminum hydroxide to the silicon micropowder is 1:4:1, average particle size 12um.

Preparation example 15

The present preparation example differs from preparation example 1 in that: the heat-conducting filler is alumina, aluminum hydroxide and silicon micropowder, and the mass ratio of the alumina to the aluminum hydroxide to the silicon micropowder is 1:3:1, average particle size 5um.

Preparation example 16

The preparation example differs from preparation example 1 in that: 40 parts of vinyl polysiloxane with the viscosity of 100cps, 24 parts of vinyl polysiloxane with the viscosity of 10000cps, 2 parts of silane treating agent, 4 parts of reinforcing agent and 100 parts of heat conducting filler.

Preparation example 17

The present preparation example differs from preparation example 1 in that: 52 parts of vinyl polysiloxane with the viscosity of 100cps, 11 parts of vinyl polysiloxane with the viscosity of 10000cps, 3 parts of silane treating agent, 10 parts of reinforcing agent and 94 parts of heat conducting filler.

Preparation example 18

The present preparation example differs from preparation example 1 in that: 50.5 parts of vinyl polysiloxane with the viscosity of 100cps, 13 parts of vinyl polysiloxane with the viscosity of 10000cps, 2 parts of silane treating agent, 4 parts of reinforcing agent and 100 parts of heat conducting filler.

Comparative preparation example 1

In contrast to preparation example 1: vinyl polysiloxane having a viscosity of 10000cps is used instead of vinyl polysiloxane having a viscosity of 100cps.

Comparative preparation example 2

Different from preparation example 1, the amount of the reinforcing agent added was 0, and 10000cps of vinyl polysiloxane was used instead of the same mass.

Comparative preparation example 3

Different from preparation example 1, the amount of the reinforcing agent added was 0, and the same mass of the heat conductive filler was used instead.

Comparative preparation example 4

The difference from preparation example 1 is that ultrafine kaolin is used as the reinforcing agent.

Examples

Example 1

Preparing a component A: transferring 85 parts of matrix into a planetary stirrer, adding 12.8 parts of vinyl polysiloxane with the viscosity of 100cps, 2 parts of polydimethylsiloxane and 0.2 part of catalyst, stirring for 15min at the rotating speed of 30-40rpm, vacuumizing, stirring and defoaming for 30min to obtain a component A;

preparing a component B: transferring 85 parts of matrix into a planetary stirrer, adding 0.2 part of carbon black color paste, uniformly stirring, adding 7.78 parts of vinyl polysiloxane with the viscosity of 100cps, 2 parts of polydimethylsiloxane, 5 parts of hydrogen-containing silicone oil and 0.02 part of inhibitor, stirring for 15 minutes at the rotating speed of 30-40rpm, vacuumizing, stirring and defoaming for 30 minutes to obtain a component B;

mixing the components A and B according to the mass fraction of 1:1, mixing and stirring uniformly to prepare the organic silicon pouring sealant, vacuumizing to exhaust bubbles, slowly pouring the organic silicon pouring sealant into a mould, and testing the performance of the organic silicon pouring sealant after the organic silicon pouring sealant is solidified.

Wherein, the matrixes in the component A and the component B are prepared by the preparation example 1, the platinum catalyst is a divinyl tetramethyl disiloxane platinum complex, and the mass percent of platinum is 5000ppm; the mass ratio of the hydrogen-containing silicone oil at the end to the hydrogen-containing silicone oil at the end side is 1:2, the viscosity of the end-side hydrogen-containing silicone oil is 20cps, the hydrogen content is 0.1%, the viscosity of the end-side hydrogen-containing silicone oil is 70cps, and the hydrogen content is 0.8%; the inhibitor is ethynyl cyclohexanol.

Example 2 to example 6

In contrast to example 1, examples 2 to 6 each produced a substrate according to a different preparation example, with specific reference to table 1.

Table 1: examples 2 to 6 corresponding to the preparation of the substrates

Example 7 to example 12

In contrast to example 1, examples 7 to 12 each produced a substrate using a different preparation example, with specific reference to Table 2.

Table 2: examples 7 to 12 examples of the preparation of substrates

Example 13 to example 18

In contrast to example 1, examples 13 to 18 each produced a substrate according to a different preparation example, with specific reference to Table 3.

Table 3: examples 13-18 corresponding preparation examples in the preparation of the substrates

Example 13	Example 14	Example 15	Example 16	Example 17	Example 18
						Preparation example 13	Preparation example 14	Preparation example 15	Preparation example 16	Preparation example 17	Preparation example 18

Example 19

The difference between the embodiment and the embodiment 1 is that the specific addition amount of the raw materials for preparing the component A and the component B is different, and specifically: preparing a component A: transferring 85 parts of matrix into a planetary stirrer, adding 9.95 parts of vinyl polysiloxane with the viscosity of 100cps, 5 parts of polydimethylsiloxane and 0.05 part of catalyst, stirring for 15min at the rotating speed of 30-40rpm, vacuumizing, stirring and defoaming for 30min to obtain a component A;

preparing a component B: transferring 85 parts of matrix to a planetary stirrer, adding 0.2 part of carbon black color paste, uniformly stirring, adding 8.7 parts of vinyl polysiloxane with the viscosity of 100cps, 1.095 parts of polydimethylsiloxane, 5 parts of hydrogen-containing silicone oil and 0.005 part of inhibitor, stirring for 15 minutes at the rotating speed of 30-40rpm, vacuumizing, stirring and defoaming for 30min to obtain the component B.

Example 20

The difference between the embodiment and the embodiment 1 is that the specific addition amount of the raw materials for preparing the component a and the component B is different, and specifically: preparing a component A: transferring 85 parts of matrix into a planetary stirrer, adding 9.8 parts of vinyl polysiloxane with the viscosity of 100cps, 5 parts of polydimethylsiloxane and 0.2 part of platinum catalyst, stirring at the rotating speed of 30-40rpm for 15min, vacuumizing, stirring and defoaming for 30min to obtain a component A;

preparing a component B: transferring 85 parts of matrix to a planetary stirrer, adding 0.4 part of carbon black color paste, uniformly stirring, adding 5.5 parts of vinyl polysiloxane with the viscosity of 100cps, 1 part of polydimethylsiloxane, 8 parts of hydrogen-containing silicone oil and 0.1 part of inhibitor, stirring for 15 minutes at the rotating speed of 30-40rpm, vacuumizing, stirring and defoaming for 30 minutes to obtain the component B.

Example 21

The difference between the embodiment and the embodiment 1 is that the specific addition amount of the raw materials for preparing the component A and the component B is different, and specifically: preparing a component A: transferring 85 parts of matrix into a planetary stirrer, adding 11.85 parts of vinyl polysiloxane with the viscosity of 100cps, 3 parts of polydimethylsiloxane and 0.15 part of platinum catalyst, stirring for 15min at the rotating speed of 30-40rpm, vacuumizing, stirring and defoaming for 30min to obtain a component A;

preparing a component B: transferring 85 parts of matrix into a planetary stirrer, adding 0.2 part of carbon black color paste, uniformly stirring, adding 6.72 parts of vinyl polysiloxane with the viscosity of 100cps, 2 parts of polydimethylsiloxane, 6 parts of hydrogen-containing silicone oil and 0.08 part of inhibitor, stirring for 15 minutes at the rotating speed of 30-40rpm, vacuumizing, stirring and defoaming for 30 minutes to obtain the component B.

Example 22

The difference between the present example and example 1 is that the hydrogen-containing silicone oil is a mixture of end hydrogen-containing silicone oil and end hydrogen-containing silicone oil in a mass ratio of 3: 7.

Example 23

The difference between the present example and example 1 is that the hydrogen-containing silicone oil is a mixture of end hydrogen-containing silicone oil and end hydrogen-containing silicone oil in a mass ratio of 4: 6.

Example 24

The difference between this example and example 1 is that the terminal hydrogen-containing silicone oil has a viscosity of 40cps and a hydrogen content of 0.06%, and the terminal hydrogen-containing silicone oil has a viscosity of 40cps and a hydrogen content of 0.85%.

Example 25

The difference between this example and example 1 is that the terminal hydrogen-containing silicone oil has a viscosity of 30cps and a hydrogen content of 0.08%, and the terminal hydrogen-containing silicone oil has a viscosity of 70cps and a hydrogen content of 0.8%.

Example 26

The present example is different from example 1 in that the hydrogen-containing silicone oil is an end side hydrogen-containing silicone oil, and the viscosity is 70cps and the hydrogen content is 0.8%.

Examples 27 to 30

In contrast to example 1, examples 27 to 30 each produced a substrate according to a different preparation example, with specific reference to Table 4.

Table 4: examples 27 to 30 preparation examples for substrates

Example 27	Example 28	Example 29	Example 30
				Comparative preparation example 1	Comparative preparation example 2	Comparative preparation example 3	Comparative preparation example 4

Comparative example

Comparative example 1

This comparative example differs from example 1 in that the matrix is replaced by a vinyl polysiloxane of equal mass.

Comparative example 2

The comparative example is different from example 1 in that the addition amount of the hydrogen-containing silicone oil is 10 parts and the part of the vinyl polysiloxane is 2.78 parts.

Comparative example 3

The comparative example is different from example 1 in that the addition amount of the hydrogen-containing silicone oil is 4 parts and the part of the vinyl polysiloxane is 8.78 parts.

Comparative example 4

The comparative example is different from example 1 in that the hydrogen-containing silicone oil is terminal hydrogen-containing silicone oil, the viscosity is 20cps, and the hydrogen content is 0.1%.

Comparative example 5

This comparative example differs from example 1 in that the inhibitor is replaced by an equal mass of vinyl polysiloxane.

Comparative example 6

This comparative example is different from example 1 in that the base was not separately prepared, but the raw materials of the respective components in the base were mixed with the raw materials of the a component and the B component, respectively.

Performance test

Detection method tensile strength: the detection is carried out by referring to GB/T528-2008, and the larger the numerical value is, the stronger the tensile strength of the product is. In the industry, when the tensile strength of the organic silicon pouring sealant is more than 2MPa, the tensile strength performance of the organic silicon pouring sealant can be determined to be good.

Viscosity: the detection is carried out by referring to GB/T40280-2021, and the larger the value, the higher the viscosity of the product is. In the industry, silicone potting adhesives can be considered low viscosity when their viscosity is below 5000 cps.

Tear strength: the detection is carried out by referring to GB/T529-2008, and the larger the numerical value is, the less possibility that the product is cracked is shown. In the industry, when the tear strength of the organic silicon pouring sealant is more than 15KN/m, the tear strength performance of the organic silicon pouring sealant can be determined to be excellent.

Data analysis

Table 5: corresponding detection data under different detection indexes in example 1 and comparative examples 1-4

Combining example 1 and comparative examples 1-4, it can be seen from table 5 that: comparative example 1 instead of using a matrix, vinyl polysiloxane was used, and the tensile strength of the finally obtained casting compound was only 1.8MPa, the tear strength was only 5KN/m, which is much lower than that of example 1, and in addition, the viscosities of both component A and component B in comparative example 1 were not more than 1900cps, which is close to half of the viscosity of example 1.

Comparative example 2 the amount of hydrogen-containing silicone oil added is 10 parts, which exceeds 5-8 parts, the viscosity of the finally prepared pouring sealant is not greatly deteriorated, but the tensile strength and the tear strength begin to decrease; comparative example 3 the amount of the hydrogen-containing silicone oil is only 4 parts, which is less than 5-8 parts, so that the viscosity of the finally prepared pouring sealant is not greatly deteriorated, but the tensile strength and the tear strength start to be reduced as well; when the addition amount of the hydrogen-containing silicone oil is controlled to be 5-8 parts, the tensile strength of the prepared pouring sealant exceeds 4MPa, and the tearing strength exceeds 24KN/m.

In comparative example 4, the hydrogen-containing silicone oil is only end hydrogen-containing silicone oil, and the finally prepared pouring sealant is gel-like and is difficult to measure the tensile strength and the tear strength.

Comparative example 5 No inhibitor was added and the tensile strength in the prepared casting compound was below 4.0MPa and the tear strength was only 18KN/m.

In comparative example 6, the raw material for preparing the substrate is directly and averagely divided into two parts, and the two parts are respectively mixed with the component A and the component B, so that the prepared organosilicon potting adhesive is viscous, the viscosity of the component A is 188000cps, and the viscosity of the component B reaches 180000cps, and the organosilicon potting adhesive is difficult to be practically used.

Table 6: corresponding detection data under different detection indexes in examples 1-6

Combining example 1, table 1 and table 6, it can be seen that: in example 2 and example 1, the vinyl contents of vinyl polysiloxanes with different viscosities are changed, the viscosities of the finally prepared A component and B component are the same, and the tensile strength is not basically different, however, the tear strength of example 1 is higher than that of example 2, and the change of the vinyl contents has an influence on the tear strength of the silicone pouring sealant.

Examples 3-4 change the mass ratio of hexamethyldisilazane to dodecyltrimethoxysilane, as can be seen in Table 6: the viscosity of both the A and B components exceeded 4000cps, while the tensile strength was substantially the same as in example 1, but the tear strength did not exceed 24.5KN/m. It can be seen that varying the mass ratio of hexamethyldisilazane to dodecyltrimethoxysilane affects the viscosity and tear strength of the overall composition.

Examples 5-6 vary the specific composition of the silane treatment agent and it can be seen that: the viscosity of the component A and the viscosity of the component B are higher, the viscosity is not lower than 4400cps, the highest viscosity even reaches 4800cps, the tensile strength and the tear strength are lower than those of the component A in example 1, and therefore, the viscosity, the tensile strength and the tear strength of the silicone pouring sealant are greatly different by changing specific components of the silicone treating agent.

Table 7: corresponding detection data under different detection indexes in examples 1 and 7 to 12

Combining example 1 and examples 7-12, the reinforcing agent was both untreated white carbon black and vinyl silicone resin, except that the addition ratio of the both was different, and it can be seen from table 7 that when the mass ratio of white carbon black to vinyl silicone resin was 8:2, the prepared pouring sealant has higher tensile strength and tearing strength under the condition of lower viscosity.

Combining example 1 and examples 9-12, the reinforcing agent was white carbon black or vinyl silicon resin, and the viscosity and vinyl content of the vinyl silicon resin were changed, as can be seen from table 7: the type of the reinforcing agent has obvious difference on the reinforcing performance, the reinforcing performance of the single white carbon black is excellent, but the thickening is more obvious; when the reinforcing agent is vinyl silicon resin and the viscosity and vinyl content of the vinyl silicon resin are randomly changed, the prepared pouring sealant has higher tensile strength and tearing strength, but has obvious thickening property. Therefore, the white carbon black and the vinyl silicone resin are used simultaneously, and the prepared organic silicon pouring sealant has good performance and moderate viscosity.

Table 8: corresponding detection data under different detection indexes in examples 1, 13 to 15

Combining example 1 and examples 13-15, it can be seen from table 8: the heat-conducting filler also has certain influence on mechanical property, and when the particle size of the heat-conducting filler is fine, the mechanical strength is good, but the corresponding viscosity is obviously increased. Therefore, the mechanical properties of the filler are promoted by selecting a filler with a suitable particle size.

Table 9: corresponding detection data under different detection indexes in examples 1 and 16 to 18

Combining example 1 and examples 16-18, it can be seen from Table 9 that: the use amounts of the vinyl polysiloxane, the silane treating agent, the reinforcing agent and the heat-conducting filler with different viscosities have certain influence on the performance of the pouring sealant, and only when 50.5 parts of 100cps vinyl polyhydrosiloxane, 13 parts of 10000cps vinyl polysiloxane, 3 parts of the silane treating agent, 10 parts of the reinforcing agent and 93.5 parts of the heat-conducting filler are used, the prepared pouring sealant has lower viscosity, but both the tensile strength and the tearing strength can reach higher values, particularly the tensile strength reaches 4.2MPa.

Table 10: corresponding detection data under different detection indexes in examples 1 and 19 to 21

Combining example 1 and examples 19-21, it can be seen from Table 10 that: the addition amount of each component is changed, and the viscosity, the tensile strength and the tearing strength of the prepared pouring sealant are basically not greatly different.

Table 11: corresponding detection data under different detection indexes in examples 1 and 22 to 26

Combining example 1 and examples 22-23, it is seen from table 11: the type, the content and the mixing ratio of the hydrogen-containing silicone oil can greatly influence the performance of the pouring sealant, and when the mass ratio of the end side hydrogen-containing silicone oil to the end hydrogen-containing silicone oil is 2; specifically, the effect of the potting adhesive is different when the hydrogen-containing silicone oil is different in viscosity and hydrogen content, especially in example 26, only the end-side hydrogen-containing silicone oil is added, the tensile strength and tear strength of the finally prepared potting adhesive are increased, while in examples 1 and 24-25, the end-side hydrogen-containing silicone oil and the end-side hydrogen-containing silicone oil are added simultaneously, and the toughness and strength of the finished product are increased while the chain is extended, so as to achieve excellent performance.

Table 12: corresponding test data for different test indexes in examples 27-30

As can be seen from table 12: in example 27, no vinyl polysiloxane having a viscosity of 100cps was used, and the potting adhesive finally obtained had high performance but had too high viscosity to be put into practical use.

In examples 28 to 30, the reinforcing agent was not used, but other components were used instead, and the properties of the finally obtained potting adhesive were poor, particularly the tensile strength, which was only 2.4MPa at most.

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.

Claims

1. The organic silicon pouring sealant with low viscosity and high strength is characterized by being formed by mixing a component A and a component B according to the mass ratio of 1.

2. The low viscosity, high strength silicone pouring sealant according to claim 1, wherein the viscosity of the vinyl polysiloxane is 100cps.

3. The low-viscosity high-strength silicone pouring sealant as claimed in claim 1, wherein the matrix comprises the following components in parts by mass: 51-76 parts of vinyl polysiloxane, 2-3 parts of silane treating agent, 4-10 parts of reinforcing agent and 93.5-100 parts of heat conducting filler, wherein the vinyl polysiloxane comprises 40-52 parts of vinyl polysiloxane with the viscosity of 100cps and 11-24 parts of vinyl polysiloxane with the viscosity of 10000 cps.

4. The low viscosity, high strength silicone pouring sealant according to claim 3, wherein the vinyl polysiloxane has a vinyl content of 0.12% to 1.2%.

5. The low-viscosity high-strength silicone pouring sealant according to claim 3, wherein the reinforcing agent comprises at least one of white carbon black and vinyl silicone resin.

6. The low-viscosity high-strength organosilicon pouring sealant according to claim 3, wherein the heat conductive filler comprises at least one of alumina, aluminum hydroxide and silica micropowder, and the mass ratio of the alumina: aluminum hydroxide: fine silica powder = (1-2): (3-4): (1-2).

7. The low viscosity, high strength silicone pouring sealant according to claim 3, wherein said silane treatment agent is at least one of methyltrimethoxysilane, vinyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, 3- (2, 3 glycidoxy) propyltrimethylsilane, n-octyltriethoxysilane, hexamethyldisilazane.

8. The low-viscosity high-strength silicone pouring sealant according to claim 1, wherein the hydrogen-containing silicone oil further comprises terminal hydrogen-containing silicone oil, and the mass ratio of the terminal hydrogen-containing silicone oil to the terminal hydrogen-containing silicone oil is 1 (2-3).

9. A method of preparing the low viscosity, high strength silicone pouring sealant according to any of claims 1-8, comprising the steps of:

stirring the substrate, the vinyl polysiloxane, the polydimethylsiloxane and the platinum catalyst for 10-20min at the rotating speed of 30-40rpm, vacuumizing, stirring and defoaming for 30min after stirring is finished to obtain a component A, and testing the viscosity of the component A;

stirring the matrix, vinyl polysiloxane, polydimethylsiloxane, hydrogen-containing silicone oil, inhibitor and carbon black color paste at the rotating speed of 30-40rpm for 10-20min, vacuumizing, stirring and defoaming for 30min after stirring is finished to obtain a component B, and testing the viscosity of the component B;

and (3) uniformly mixing and stirring the component A and the component B according to the mass ratio of 1.