WO2020143714A1

WO2020143714A1 - Silicone sealant, device sealed by using sealant and use of sealant

Info

Publication number: WO2020143714A1
Application number: PCT/CN2020/071196
Authority: WO
Inventors: Yingfa SUN; Haibin Li; Ming Xiao; Dan Su; Shouping Li
Original assignee: Tonsan Adhesive, Inc.
Priority date: 2019-01-11
Filing date: 2020-01-09
Publication date: 2020-07-16
Also published as: CN109796928A; CN109796928B

Abstract

An addition-type silicone sealant including a polyorganosiloxane, an inhibitor, a hydrogen-containing silicone oil, and a metal catalyst. The addition-type silicone sealant solidifies when being exposed to the atmospheric environment and does not solidify when not being exposed to the atmospheric environment.

Description

[Title established by the ISA under Rule 37.2] SILICONE SEALANT, DEVICE SEALED BY USING SEALANT AND USE OF SEALANT

TECHNICAL FIELD

The present disclosure relates to the field of silicone, and more particularly to an addition-type silicone sealant, and to a device sealed by using the addition-type silicone sealant and to the use of the addition-type silicone sealant.

BACKGROUND

Various kinds of equipment need to be waterproof and often also gas-proof. One solution is to seal the parts of the equipment where two or more parts meet. For example, two or more flange faces of an insulation disc, such as on a high-voltage switch, can be sealed at the interface formed where the flange faces meet.

Currently available options for sealing parts of equipment together include non-solidifying sealants such as silicone grease, devices such as gaskets, and solidifying sealants such as condensation silicone sealants and polyurethane sealants. A seal formed with silicone grease is easy to disassemble, but because silicone grease does not cure, fluid can leak through such a seal when the equipment is in use. Fluids often leak through silicone grease seals when the equipment is operated at high temperatures. Gaskets often require a high clamping force at the interface for the gasket to be effective. In certain high pressure operating conditions, such as when used with a high-voltage switch, a gasket alone often does not meet the requirements of sealing. Condensation silicone sealants, polyurethanes, or other materials that cure after being applied are available for sealing. Once cured, these materials adhere to the sealing face to form a seal between two or more parts. However, when the equipment needs to be disassembled, it is often difficult to separate the two or more parts from each other, and it is often also dificult to remove the sealant from the sealing faces due to the strong bonding.

SUMMARY

In view of the existing technology mentioned above and the technical problem thereof, a sealant that is easy to separate from the equipment it is applied to and that can achieve a suitable seal is needed. The above purpose can be achieved by using a specific addition-type silicone sealant. After the application of the addition-type silicone sealant, any silicone sealant that flows through a gap defined between two parts of the equipment is exposed to the atmosphere. The exposed portion of the sealant solidifies, forming a seal between the parts of equipment so as to prevent liquids (such as oil inside the equipment) from flowing out of the equipment, affecting the appearance or performance of the equipment. The portion of the sealant that is not exposed to the atmosphere does not solidify, which facilitates the disassembly and repair of the equipment.

An object of the present disclosure is to provide an addition-type silicone sealant.

Another object of the present disclosure is to provide a device with a sealing face sealed by the addition-type silicone sealant.

Another object of the present disclosure is to provide the use of the addition-type silicone sealant in sealing the sealing face in the device.

One aspect of the present disclosure provides an addition-type silicone sealant, which comprises a polyorganosiloxane with an unsaturated carbon-carbon double bond, and an inhibitor in liquid form at atmospheric pressure and a temperature of from 0℃ to 80℃. The addition-type silicone sealant includes a hydrogen-containing silicone oil, and a metal catalyst. The addition-type silicone sealant solidifies when exposed to the atmospheric environment and does not solidify when not being exposed to the atmospheric environment.

The addition-type silicone sealant has the following characteristics. Compared with silicone grease, the addition-type silicone sealant does not allow leakage of liquids through the seal, even when the equipment the seal is applied to is operating at high temperatures. This can help prevent contamination of the equipment by the liquid being contained. Compared with a gasket, the addition-type silicone sealant does not require a large clamping force and can meet the sealing requirements. Compared with condensation silicone and polyurethane sealants, the portion of the addition-type silicone sealant that is not exposed to the atmospheric environment does not solidify and is easy to disassemble and repair. The addition-type silicone sealant does not solidify under the sealed condition as compared with a conventional addition-type silicone sealant, so that volume shrinkage does not occur and a micro-gap is not generated at the interface, and therefore does not affect the sealing effect.

Another aspect of the present disclosure provides a device with one or more sealing faces, one or more of which are sealed with an addition-type silicone sealant. The addition-type silicone sealant solidifies when exposed to the atmospheric environment and does not solidify when not exposed to the atmosphere.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a cross-sectional view of an embodiment of a sealing device for a battery assembly.

FIG. 2 shows a top view of an embodiment of a sealing device for a battery assembly after removing the cover.

FIG. 3 shows a top view of an embodiment of a flange sealing face contained in a high-voltage switch.

DETAILED DESCRIPTION

Disclosed herein is an addition-type silicone sealant which includes a polyorganosiloxane with an unsaturated carbon-carbon double bond, an inhibitor in liquid form at atmospheric pressure and a temperature of from 0 ℃to 80 ℃, a hydrogen-containing silicone oil, and a metal catalyst. The addition-type silicone sealant solidifies when exposed to the atmospheric environment and does not solidify when not being exposed to the atmospheric environment.

As used herein "solidification" refers to the formation of a solid material having a three-dimensional network structure by a reaction of the material.

As used herein, the term "addition-type silicone sealant solidifies when exposed to the atmospheric environment" means the portion of the that is sealant exposed to the atmospheric environment, such as the face (or surface) of the sealant, becomes solid by the formation of a three-dimensional network structure by a crosslinking reaction (e.g., a curing reaction) to form a skin. The solid material produced is elastic in the atmospheric environment, does not flow, has a fixed shape, and has a certain hardness and tensile modulus. When only the face (or surface) of the sealant solidifies, the thickness of the solid formed is greater than 0 mm, but is usually less than 20 mm, preferably from 0.5 mm to 10 mm.

As used herein, the term "does not solidify when not exposed to the atmospheric environment" means that after the sealant disclosed herein is applied, when the part of the sealant exposed to the atmospheric environment solidifies, the part of the sealant which is not exposed to the atmospheric environment (i.e. the temperature and pressure that the exposed and unexposed portions of the sealant are subject to are the same) does not become solid. That is, the portion of the sealant that is not exposed to the atmospheric environment, for example remains between two parts of the equipment, does not become a solid material having a three-dimensional network structure.

For purposes of the present disclosure, the pressure of the atmospheric environment is understood to be about one atmosphere in pressure. In the present disclosure, when the addition-type silicone sealant is exposed to the atmospheric environment, the ambient temperature is not particularly limited and may be lower than room temperature (from 20℃to 25℃) or higher than room temperature. For example, the ambient temperature may be from 0℃, 10℃, 20℃, 40℃, or 80℃, to 100℃, 150℃, or even 200℃, or a temperature between any pair of the foregoing values. Generally, a typical ambient temperature is from 10℃to 100℃, preferably from 80℃to 100℃.

Under heating conditions, the progress of solidification accelerates. Therefore, in a preferred embodiment, the addition-type silicone sealant according to the present disclosure meets one or both of conditions a) and b) : a) the addition-type silicone sealant solidifies within 10 days, preferably within five days, when being exposed to an atmospheric environment of 80 to 100 ℃, and does not solidify within 10 days, preferably does not solidify within one month when not being exposure to the aforementioned atmospheric environment; and b) said addition-type silicone sealant solidifies within 90 days, preferably solidifies within 60 days when being exposed to an atmospheric environment of normal temperature, and does not solidify within 180 days, preferably does not solidify within 24 months when not being exposed to the aforementioned atmospheric environment.

Silicone Sealants

Silicone sealants are classified into two types: condensation-type and addition-type. The condensation-type silicone sealants refers to those in which the hydroxyl polyorganosiloxane and silicone crosslinking agent eliminates small molecules with the action of the catalyst, so as to achieve curing by cross-linking. Addition-type silicone sealant refers to silicone sealants where the unsaturated carbon-carbon double bond of the polyorganosiloxane opens and reacts with the hydrogen on the silicon atom in the hydrogen-containing silicone oil to cure.

Polyorganosiloxane

In the present disclsoure, the polyorganosiloxane with an unsaturated carbon-carbon double bond is a matrix polymer. In general, the main chain of polyorganosiloxane includes repeating units of organic silicon-oxygen bonds, and the main chain may contain pendant groups (such as methyl groups) or pendant chains. The polyorganosiloxane with an unsaturated carbon-carbon double bond can be linear or cyclic, preferably linear polyorganosiloxane.

According to the present disclosure, the polyorganosiloxane contains an unsaturated carbon-carbon double bond. Polyorganosiloxane may contain any group with an unsaturated carbon-carbon double bond. Alkenyl or acrylate groups are some example groups with an unsaturated carbon-carbon double bond. Alkenyl groups are preferred. For the alkenyl, it is advantageous to be a linear or branched alkenyl group with two to eight carbon atoms or a cycloalkenyl group with three to eight carbon atoms, such as vinyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and preferably linear or branched alkenyl group with two to four carbon atoms, particularly vinyl group.

These groups with unsaturated carbon-carbon double bond are generally bonded to the silicon atoms of the polyorganosiloxane main chain, and in a preferred embodiment are bonded to the terminal silicon atom of the polyorganosiloxane main chain. The number of unsaturated carbon-carbon double bonds contained in the polyorganosiloxane is usually two or more per molecule, preferably two to five per molecule. In a particularly preferred embodiment, the polyorganosiloxane with an unsaturated carbon-carbon double bond is preferably terminal vinyl polydimethoxysilane (also known as "terminal vinyl silicone oil" ) . Particularly suitable embodiments include polyorganosiloxanes with an unsaturated carbon-carbon double bond and a viscosity from 100 mPa.sto 100,000 mPa.s, preferably 3000 mPa.s to 30,000 mPa.s.

Silicone Oil

The addition-type silicone sealant further comprises a hydrogen-containing silicone oil. The hydrogen-containing silicone oil is a crosslinking agent for the addition-type silicone sealant and has repeating Si-O bonds as the main chain and two or more, preferably three or more, hydrogen atoms bonded to silicon atoms in one molecule. Hydrogen-containing silicone oil may also have the pendant group or pendant chains attached to the Si-O main chain. The hydrogen content of the hydrogen-containing silicone oil is advantageously from 0.1%to 1.2%by weight, preferably from 0.15%to 0.5%by weight. The amount of the hydrogen-containing silicone oil may be from 0.15 to 30 parts by mass, preferably from 1 to 10 parts by mass, based on 100 parts by mass of the polyorganosiloxane with an unsaturated carbon-carbon double bond.

Inhibitor

The addition-type silicone sealant also comprises an inhibitor. The inhibitor is used to inhibit the curing reaction of the addition-type silicone sealant. Suitable inhibitors include those in liquid form at atmospheric pressure and a temperature of from 0℃to 80℃, preferably in liquid form at room temperature and atmospheric pressure. The molecular weight of the inhibitor is usually less than or equal to 500. The inhibitor includes any suitable inhibitor capable of inhibiting the curing reaction of the addition-type silicone sealant and the formation of the three-dimensional network structure. In general, the inhibitor may be a compound of nonmetallic element which bears a shared electron pair, such as a compound containing N, P and/or S, a compound containing an alkenyl, and combinations thereof.

As the compound containing N, examples include azo compounds or compounds containing one or more groups selected from primary amino, secondary amino, tertiary amino, cyano, oximino, nitroso, hydrazino and O=C=N-. The azo compound may be azo methane. As the compound containing one or more of primary, secondary and tertiary amino, it may be tributyl amine, triethylamine, diethylamine, N, N-diethylamino trimethylsilane, amino triethoxysilane, and (diisopropylamino) trimethylsilane. As the compound with cyano, it may be adiponitrile. As the compound with oximino, it may be vinyl tri (methyl isobutyl ketone oximino) silane. As the compounds with nitroso, it may be N-dimethyl nitrosamine and N-diethyl nitrosamine. As the compound with hydrazino, it may be 2-hydrazino ethanol. As the compound with O=C=N-, it may be toluene diisocyanate (TDI) and isophorone diisocyanate (IPDI) .

As the compound containing P, it may be a compound containing phosphate ester group and/or a phosphine group. As the compound with phosphate ester group, it may be triethyl phosphite, triethyl phosphate and trimethyl phosphate. As the compound containing phosphine, it may be triethyl phosphine.

As the compound containing S, it may be a compound containing one or more of the following groups: -S-, sulfone group and mercapto. As the compound with -S-, it may be dimethyl sulfide and ethyl sulfide. As the compound with a sulfone group, it may be thionyl chloride and dimethyl sulfoxide. As the compound with mercapto, it may be ethanethiol, 2-methyl-3-furanthiol, and methanethiol.

As the inhibitor containing alkenyl, it may be a compound containing one or more of vinyl, maleate ester and fumarate ester group. As the compound containing vinyl, it may be one or more of vinyl trimethoxysilane, vinyl triethoxysiloxane, tetramethyl divinyl disiloxane, dimethoxymethyl vinyl silane and tetramethyl tetravinyl cyclotetrasiloxane. As the compound with maleate ester group, it may be one or more of diallyl maleate, dimethyl maleate, diethyl maleate, and dipropyl maleate. As the compound with fumarate ester group, it may be one or more of monomethyl fumarate, monoethyl fumarate, diethyl fumarate and dipropyl fumarate. The alkenyl-containing siloxane compound as the inhibitor is different from the polyorganosiloxane with an unsaturated carbon-carbon double bond used herein. The latter is a polymer, and its molecular weight is usually more than 5000, far greater than the former.

As the compound containing alkynyl, it may be alkyne alcohols, such as 3-methyl-1-butyn-3-ol, propargyl alcohol, 2-butyn-1-ol, 3, 5-dimethyl-1-hexyn-3-ol, 3-propyl-butyn-3-ol and 3-octyl-1-butyn-3-ol.

In the present disclosure, based on 100 parts by mass of polyorganosiloxane with an unsaturated carbon-carbon double bond, the amount of inhibitor is usually one to five parts by mass, preferably one to four parts by mass.

Catalyst

The addition-type silicone sealant of the present invention also includes a metal catalyst. The catalyst is used to catalyze the addition reaction between polyorganosiloxane with an unsaturated carbon-carbon double bond and hydrogen atom bonded to the silicon atom in the hydrogen-containing silicone oil, so as to convert the silicone sealant into a three-dimensional network structure and become solid. As the metal catalyst, it can be any catalyst that can catalyze the addition reaction between polyorganosiloxane with an unsaturated carbon-carbon double bond and hydrogen atom bonded to the silicon atom in the hydrogen-containing silicone oil. Suitable metal catalysts include platinum catalyst, rhodium catalyst or any combination thereof. Platinum catalyst is preferable. As examples of platinum catalyst, there may be mentioned chloroplatinic acid, 1,3-divinyl-1, 1, 3, 3-tetramethyldisiloxane platinum complex, di (ethynyl) (1, 5-cyclooctadiene) platinum complex, di (ethynyl) (bicyclo [2.2.1] hept-2, 5-diene) platinum complex, di (ethynyl) (1, 5-dimethyl-1, 5-cyclooctadiene) platinum complex, di (ethynyl) (1, 6-dimethyl-1, 5-cyclooctadiene) platinum complex, diethyl phthalate platinum complex or any combination thereof. As examples of rhodium catalyst, rhodium chloride, rhodium carbonyl and triphenylphosphine rhodium carbonyl can be mentioned.

The amount of the metal catalyst is advantageously from 0.001 to two parts by mass, preferably from 0.1 to one part by mass, based on 100 parts by mass of the polyorganosiloxane with an unsaturated carbon-carbon double bond. When the amount of inhibitor exceeds five parts by mass, the amount of catalyst will increase. The amount of the catalyst should not be too high. In some instances, having a high level of catalyst may be undesirable from a cost perspective. If the amount of the metal catalyst is too high, the amount of the inhibitor needs to be increased to achieve suitable inhibition, which can be undesirable. When the amount of inhibitor is less than one part by mass, it will affect the storage stability of the sealant. If the amount of the metal catalyst is too low, the part of the sealant exposed to the atmospheric environment in some instances may not suitably solidify.

Other Components

The addition-type silicone sealant of the present invention may also comprise filler. The filler may be one or more of alumina, aluminum hydroxide, magnesium oxide, magnesium hydroxide, silica micropowder, aluminum nitride, boron nitride, silver powder, calcium carbonate, talc and white carbon black, preferably white carbon black. The amount of the filler may be from one to 600 parts by mass, preferably from two to 100 parts by mass, based on 100 parts by mass of the polyorganosiloxane with an unsaturated carbon-carbon double bond.

The addition-type silicone sealant of the present invention may further comprise pigment, antifoaming agent, flame retardant or the like according to performance requirements.

The addition-type silicone sealant of the present invention may be one-component or multi-component. When the sealant is multi-component, the catalyst, the hydrogen-containing silicone oil and the polyorganosiloxane with an unsaturated carbon-carbon double bond are preferable in a separate package. That is, one or two of the catalyst, the hydrogen-containing silicone oil and the polyorganosiloxane with an unsaturated carbon-carbon double bond are packaged separately from the rest of the components. For ease of handling, it is preferred that the addition-type silicone sealant of the present invention is one-component.

According to another aspect, the instant disclosure provides a device with one or more sealing faces, one or more of which are adapted to be sealed with an addition-type silicone sealant. The addition-type silicone sealant solidifies when being exposed to the atmospheric environment and does not solidify when not being exposed to the atmospheric environment. In a preferred embodiment, the addition-type silicone sealant used is the addition-type silicone sealant of the present disclosure.

After the sealant of the present disclosure is injected into the sealing face, part of the sealant is exposed to the atmosphere through a gap (such as a bolt hole) , and the sealant exposed to the atmosphere undergoes a cross-linking reaction to form a three-dimensional network structure and solidifies. After solidification, the resulting solid material having the three-dimensional network structure insulates the unsolidified part of the sealant from the atmosphere, thereby sealing it between the device and the solid portion of the sealant and inhibits further solidification. In this manner, solidification of the sealant can be limited to the portion of sealant that is exposed to the atmosphere, such as the portion that flows out of a gap defined by the equipment, for example between two or more adjacent pieces of equipment.

In a preferred embodiment, the equipment disclosed herein includes a sealing face with one or more annular grooves. The addition-type silicone sealant can be positioned in at least one of the annular grooves. In order to facilitate injection of the addition-type silicone sealant into the grooves, it is advantageous that the bottom of the at least one annular groove and/or the other side opposite to the annular groove are provided with a sealant injection hole. After the equipment is assembled, the sealant is injected into the groove through the injection hole. The total number of sealant injection holes is usually at least two, and preferably at least two of the sealant injection holes are symmetrically distributed with respect to the center line of the sealing face. The center line is an axis perpendicular to the sealing face. At least one sealant hole can be reserved for removing air in the groove during the sealant injection. After the sealant injection is completed, the sealant injection hole can be sealed with a plug.

In a further preferred embodiment of the device, the sealing face has two annular grooves and are juxtaposed on the sealing face, and an annular gasket is arranged in the groove near the center of the sealing face, and the groove away from the center of the sealing face is filled with the addition-type silicone sealant. The annular gasket is also used to seal the sealing face.

In some embodiments, the sealing face is additionally fixed by one or more of bolts, rivets or welding. In some embodiments, the sealing face is a flange sealing face. For example, the device can be a high-voltage switch. The sealing face can be the face on the high-voltage switch that needs to be sealed, such as the flange sealing face of the insulation disc and the sealing face at the pipe joint.

The device may be a sealing device for a battery assembly. An embodiment of a sealing device 2 is shown in FIG. 1 and FIG. 2. FIG. 1 is a cross-sectional view of the sealing device 2. FIG. 2 shows a top view of the sealing device 2 with the cover removed. The sealing device 2 includes a box 10, cover 20, and an interface 30 is defined between the box 10 and the cover 20. The box 10 defines cavity 11 that has an interior volume for accommodating additional components, such as a battery. The cover 20 is arranged on the box 10. The box 10 defines a first opening 12, and a first flange 13 is positioned along the circumference of the first opening 12. The cover 20 defines a second opening 21, and a second flange 22 is positioned along the circumference of the second opening 22. The first flange 13 and the second flange 22 form the sealing faces of the sealing device 2. A sealant, such as those described herein, can be positioned at the interface 30 between the sealing faces to seal the connection between the box 10 and the cover 20. As shown, the box 10 and the cover 20 can be connected by a fastener 40. In some instances, fastener 40 is a bolt and nut. The first flange 13 can define a first mounting hole, the second flange 22 can define a second mounting hole, and the first mounting hole and the second mounting hole axis can be position coaxially from each other such that the fastener 40 can be positioned through the first mounting hole and the second mounting hole to realize the connection of the fastener 40 to the box 10 and the cover 20.

The device may also be a high-voltage switch. An embodiment of the sealing face 48 of a high-voltage switch 46 is shown in FIG. 3. The sealing face 48 includes a flange 50 defining two or more grooves, such as a first groove 51 located radially outward from the center of the sealing face and a second groove 52 located radially closer to center of the sealing face 48. The first groove 51 includes a plurality of mounting holes 60 and multiple sealant injection holes 70. The addition-type silicone sealant can be positioned in the first groove 51 to form a first seal. The addition-type silicone sealant can be positioned in the second groove 52 to form a second seal. Additionally or alternatively, a gasket can be located in the second groove 52 to form a second seal.

According to another aspect, use of the addition-type silicone sealant according to the present invention in sealing the sealing face in the device according to the present invention is provided.

By using the addition-type silicone sealant of the present invention to seal all or part of the sealing face in the device of the present invention, the portion of the sealant that is exposed to the atmospheric environment solidifies, and inhibits flowing of the sealant, while the part of the sealant not being exposed to the atmospheric environment does not solidify, which makes the sealing face easily to be disassembled and cleaned.

Examples

The present invention will now be further described in combination with examples. It should be noted that these examples are merely illustrative and are not to be construed as limiting the scope of the present disclosure.

Unless otherwise stated, the units of amount of raw material used is in parts by mass. The numerical range means any value in the range can be taken, for example one to 30 parts means that 10 parts, 15 parts, 20 parts, and the like can be taken.

Comparative Example 1

One hundred parts of methyl polydimethylsiloxane (from Jiangxi Xinghuo Silicone Co., Ltd., 201 silicone oil-1000 cp) with a kinematic viscosity of 1000 mm ² /s and 15 parts of fumed silica were stirred in a stirred tank for one hour. The product obtained is a silicone grease.

Comparative Example 2

One hundred parts of α, ω-dihydroxypolydimethylsiloxane (from Xin'an Chemical) having a kinematic viscosity of 20,000 mm ²/s and 80 parts of nano-calcium carbonate were stirred in a tank for 30 minutes. Thereafter, nine parts of methyltrimethoxysilane was added and stirred for 10 minutes. Then, three parts of fumed silica was added and stirred for 30 minutes. Next, 0.1 part of γ-glycidoxypropyltrimethoxysilane and 0.01 part of dibutyltin diacetate were added and stirred for 10 minutes. The product obtained is a condensation-type silicone sealant.

Comparative Example 3

One hundred parts of terminal vinyl polydimethylsiloxane having a kinematic viscosity of 10,000 mm ²/s ( (from Run He Chemical, Vi303) , 0.01 part of di (ethynyl) (1, 5-dimethyl-1, 5-cyclooctadiene) platinum complex, two parts of fumaric acid (powder) , 30 parts of hydrogen-containing silicone oil with a hydrogen content of 0.1%by weight (Run He Chemical, RH-H6) and 600 parts of alumina were stirred in a stirred tank for 1.5 hours. The obtained product an addition-type silicone sealant.

Comparative Example 4

One hundred parts of terminal vinyl polydimethylsiloxane having a kinematic viscosity of 10,000 mm ²/s (from Run He Chemical, Vi303) , 0.01 part of di (ethynyl) (1, 5-dimethyl-1, 5-cyclooctadiene) platinum complex, 0.5 parts of diallyl maleate, 30 parts of hydrogen-containing silicone oil with a hydrogen content of 0.1%by weight (from Run He Chemical, RH-H6) and 600 parts of alumina were stirred in a stirred tank for 1.5 hours. The obtained product is an addition-type silicone sealant.

Illustrative Example 1

Fifty parts of terminal vinyl polydimethylsiloxane with a kinematic viscosity of 100,000 mm ²/s (Run He Chemical, Vi301) and 50 parts of terminal vinyl polydimethylsiloxane with a kinematic viscosity of 100 mm ²/s (Run He Chemical, Vi321) , two parts of 3000ppm chloroplatinic acid solution in isopropanol, five parts of tetramethyl tetravinyl cyclotetrasiloxane, 0.15 part of hydrogen-containing silicone oil with a hydrogen content of 1.2%by weight (Run He Chemical, RH-H512) and one part of fumed silica were stirred in a stirred tank for one hour to obtain a silicone sealant.

Illustrative Example 2

One hundred parts of terminal vinyl polydimethylsiloxane having a kinematic viscosity of 10,000 mm ²/s (Run He Chemical, Vi303) , 0.01 part of di (ethynyl) (1, 5-dimethyl-1, 5-cyclooctadiene) platinum complex, one part of diallyl maleate, 30 part of hydrogen-containing silicone oil with a hydrogen content of 0.1%by weight (Run He Chemical, RH-H6) 30 parts and 600 parts of alumina were stirred in a stirred tank for 1.5 hours to obtain a silicone sealant.

Illustrative Example 3

One hundred parts of terminal vinyl polydimethylsiloxane (Run He Chemical, Vi333) with a kinematic viscosity of 3,000 mm ²/s, 0.1 part of diethyl phthalate platinum complex, two parts of 3-octyl-1-butyn-3-ol, five parts of hydrogen-containing silicone oil with a hydrogen content of 0.5%by weight (Run He Chemical, RH-H503) and 40 parts of calcium carbonate were stirred in a stirred tank for 0.5 hours to obtain a silicone sealant.

Illustrative Example 4

One hundred parts of terminal vinyl polydimethylsiloxane having a kinematic viscosity of 20,000 mm ²/s (Run He Chemical, Vi302) , one part of diethyl phthalate platinum complex, four parts of vinyl trimethoxysilane, 20 parts of hydrogen-containing silicone oil with a hydrogen content of 0.18%by weight (Run He Chemical, RH-H33) and 100 parts of calcium carbonate were stirred in a stirred tank for one hour to obtain a silicone sealant.

Illustrative Example 5

One hundred parts of terminal vinyl polydimethylsiloxane having a kinematic viscosity of 20,000 mm ²/s (Run He Chemical, Vi302) and 3 parts of rhodium chloride, two parts of diethylamine, two parts of ethanethiol, 20 parts of hydrogen-containing silicone oil with a hydrogen content of 0.18%by weight (Run He Chemical, RH-H33) and 100 parts of calcium carbonate were stirred in a stirred tank for one hour to obtain a silicone sealant.

Illustrative Example 6

One hundred parts of terminal vinyl polydimethylsiloxane with a kinematic viscosity of 20,000 mm ²/s (Run He Chemical, Vi302) , one part of diethyl phthalate platinum complex, one part of N-nitrosodiethylamine, two parts of triethyl phosphate, 20 parts of hydrogen-containing silicone oil with a hydrogen content of 0.18%by weight (Run He Chemical, RH-H33) and 100 parts of calcium carbonate were stirred in a stirred tank for one hour to obtain a silicone sealant.

Illustrative Example 7

One hundred parts of terminal vinyl polydimethylsiloxane having a kinematic viscosity of 20,000 mm ²/s (Run He Chemical, Vi302) , one part of diethyl phthalate platinum complex, one part of azomethane, two parts of 2-hydrazino ethanol, 20 parts of hydrogen-containing silicone oil with a hydrogen content of 0.18%by weight (Run He Chemical, RH-H33) and 100 parts of calcium carbonate were stirred in a stirred tank for one hour to obtain a silicone sealant.

Illustrative Example 8

One hundred parts of terminal vinyl polydimethylsiloxane having a kinematic viscosity of 20,000 mm ²/s (Run He Chemical, Vi302) , one part of diethyl phthalate platinum complex, one part of dimethyl sulfide, two parts of adiponitrile, 20 parts of hydrogen-containing silicone oil with a hydrogen content of 0.5%by weight (Run He Chemical, RH-H33) and 100 parts of calcium carbonate were stirred in a stirred tank for one hour to obtain a silicone sealant.

The compositions prepared in each of the Comparative Examples and the Illustrative Examples were uniformly knife-coated on a 45 #carbon steel sheet of 25 mm by 100 mm, and the thickness was about 1.5 to 2.5 mm, and two iron wires having a diameter of one mm were placed on the sealant layer in parallel. The iron wire was positioned perpendicular to the long side of the steel sheet, and the carbon steel sheet of the same size and same model was completely covered on the sealant. After compressing, it was fixed by a butterfly clip and allowed to stand at room temperature for 30 days. Then, observation was made to see whether the part of the sealant exposed to the air (including the sealant draining or overflowing from the four edges of the two steel sheets) was solidified. Then, it was placed in a tray covered by white paper, placed in an oven at 80 ℃, and allowed to stand for 10 days before being taken out. Observation was made to see whether there is obvious overflow of the sealant around the steel sheet and marks of infiltration of silicone oil into the white paper, to see whether the part of the sealant exposed to the air (including the sealant draining or overflowing from the four edges of the two steel sheets) is solidified, to see whether the inner sealant completely located between the two steel sheets (i.e., the part of the sealant that was not exposed to air) was solidified, and to see whether the two steel sheets can be separated by hand. Five groups of experiments were carried out in parallel for each example and the results are summarized as follows:

It can be seen from the experimental results that, compared with silicone grease, the oil will not drain from the sealant of the Illustrative Examples, or flow and cause contamination under heating. When compared with the condensation-type organic silicone, the sealant of the Illustrative Examples allows for easy disassembly. Compared with the use of an inhibitor which is solid under normal pressure (e.g. one standard atmosphere) and a temperature of from 0℃to 80℃(fumaric acid) , the sealant of the present invention does not solidify under room temperature or under heating. When the amount of the inhibitor is too small (comparative example 4) , the part of the addition-type silicone sealant which is not exposed to the atmosphere solidifies. Volume shrinkage will occur due to the solidification of the sealant, and micro-gap will generate between the sealant and the sealing face, and thus the sealing cannot meet the requirements. Other embodiments are in the claims.

Claims

An addition-type silicone sealant comprising:

a polyorganosiloxane with an unsaturated carbon-carbon double bond,

an inhibitor in liquid form at atmospheric pressure and a temperature of from 0 ℃ to 80 ℃,

a hydrogen-containing silicone oil, and

a metal catalyst,

wherein the addition-type silicone sealant solidifies when being exposed to the atmospheric environment and does not solidify when not being exposed to the atmospheric environment.
The addition-type silicone sealant according to claim 1, wherein the sealant meets one or both of conditions a) and b) :

a) said addition-type silicone sealant solidifies within 10 days, preferably solidifies within 5 days when being exposed to an atmospheric environment of from 80 ℃ to 100 ℃, and does not solidify within 10 days, preferably does not solidify within 1 month when not being exposed to the atmospheric environment; and

b) said addition-type silicone sealant solidifies within 90 days, preferably solidifies within 60 days when being exposed to the atmospheric environment, and does not solidify within 180 days, preferably does not solidify within 24 months when not being exposed to the atmospheric environment.
The addition-type silicone sealant according to claim 1 or 2, wherein said inhibitor is liquid at room temperature and pressure;

preferably said inhibitor is selected from one or more of the group consisting of a compound containing one or more atoms selected from N, P and S, and an organic compound having one or more alkenyl groups and/or one or more alkynyl groups;

more preferably, said inhibitor is selected from one or more of the group consisting of azo compound, alkynol and compound containing one or more group selected from primary amino, secondary amino, tertiary amino, cyano, oximino, nitroso, hydrazino, phosphino, mercapto, -S-, sulfone, phosphate ester, maleate ester, fumarate ester, O=C=N-, alkynyl and vinyl;

further preferably, said inhibitor is selected from one or more of the group consisting of tributylamine, triethylamine, diethylamine, N, N-diethylaminotrimethylsilylaminotriethoxysilane, (diisopropyl) amino) trimethylsilane, adiponitrile, vinyl tris (methyl isobutyl ketoximino) silane, toluene diisocyanate (TDI) , isophorone diisocyanate (IPDI) , N-dimethyl nitrosamine, N nitrosodiethylamine, 2-hydrazinoethanol, azomethane, triethyl phosphite, triethyl phosphate, trimethyl phosphate, triethyl phosphine, dimethyl sulfide, diethyl sulfide, thionyl chloride, dimethyl sulfoxide, ethanethiol, 2-methyl-3 furanthiol, methanthiol, vinyl trimethoxy silane, vinyl triethoxy siloxane, tetramethyldivinyldisiloxane, dimethoxymethylvinylsilane, tetramethyltetravinylcyclotetrasiloxane, diallyl maleate, dimethyl maleate, monomethyl fumarate, diethyl fumarate, diethyl maleate, diethyl fumarate, dipropyl maleate, dipropyl fumarate, 3-methyl-1-butyn-3-ol, propargyl alcohol, 2-butyn-1-ol, 3, 5-dimethyl-1-hexyn-3-ol, 3 propyl-butyn-3-ol and 3-octyl-1-butyn-3-ol.
The addition-type silicone sealant according to any of claims 1 to 3, wherein the amount of the inhibitor is 1 to 5 parts by mass; preferably 1 to 4 parts by mass based on 100 parts by mass of the polyorganosiloxane.
The addition-type silicone sealant according to any of claims 1 to 4, wherein the polyorganosiloxane is vinyl silicone oil, preferably terminal vinyl silicone oil; more preferably terminal vinyl silicone oil having a viscosity of from 100 mPa.s to 100,000 mPa.s, particularly from 3,000 mPa.s to 30,000 mPa.s.
The addition-type silicone sealant according to any of claims 1 to 5, wherein the metal catalyst is a platinum catalyst or rhodium catalyst or any combination of said two catalysts, preferably platinum catalyst.
The addition-type silicone sealant according to any of claims 1 to 6, wherein the hydrogen content of the hydrogen-containing silicone oil is from 0.1%to 1.2%by weight, preferably from 0.15%to 0.5%by weight.
The addition-type silicone sealant according to any of claims 1 to 7, wherein the sealant meets one or both of conditions i) and ii) :

i) the amount of the hydrogen-containing silicone oil is from 0.15 to 30 parts by mass, preferably from 1 to 10 parts by mass; and

ii) the amount of the metal catalyst is from 0.001 to 2 parts by mass, preferably from 0.1 to 1 part by mass,

in each case based on 100 parts by mass of the polyorganosiloxane.
A device with one or more sealing faces, one or more of which are sealed with an addition-type silicone sealant, wherein the addition-type silicone sealant solidifies when being exposed to the atmosphere and does not solidify when not being exposed to the atmosphere.
The device according to claim 9, wherein the addition-type silicone sealant is an addition-type silicone sealant according to any of claims 1 to 8.
The device according to claim 9 or 10, wherein said sealing face has one or more annular grooves and said addition-type silicone sealant is located in at least one of said annular grooves.
The device according to claim 11, wherein the bottom of said at least one annular groove and/or the other side opposite to the annular groove is provided with at least one sealant injection hole.
The device according to claim 12, wherein the total number of the sealant injection holes is at least two; preferably at least two of said sealant injection holes are symmetrically distributed with respect to the center lines of the sealing faces.
The device according to any of claims 11 to 13, wherein a sealing face of said one or more sealing faces has two annular grooves juxtaposed on the sealing face, and an annular gasket is provided in the groove near the center of the sealing face, and the groove away from the center of the sealing face is filled with the addition-type silicone sealant.
The device according to any of claims 9 to 14, wherein the sealing face is a flange sealing face.
The device according to claim 15, wherein the device is a high-voltage switch.
Use of the addition-type silicone sealant according to any of claims 1 to 7 in sealing the sealing face in the device according to any of claims 8 to 16.