Acid and alkali resistant and high temperature resistant room temperature vulcanized silicone rubber and preparation method thereof

Abstract

The invention provides acid and alkali resistant and high temperature resistant room temperature vulcanized silicone rubber and a preparation method thereof, and belongs to the technical field of silicone rubber. The acid and alkali resistant and high temperature resistant room temperature vulcanized silicone rubber comprises a component A and a component B which are mixed according to a mass ratio of 10: 1, and the component A comprises 100 parts of a, w-dihydroxy polydimethylphenyl siloxane, 10-20 parts of white carbon black, 30-40 parts of silica powder and 2-5 parts of a heat resistant additive; the component B comprises 100 parts of dimethyl silicone oil, 200 parts of black paste, 100-150 parts of a cross-linking agent, 25-50 parts of a coupling agent and 15-25 parts of a catalyst; through cooperative use of a, w-dihydroxy polydimethylphenyl siloxane, a heat-resistant additive treated by silazane, fumed silica treated by silazane, silica powder and the like, it is guaranteed that the silicone rubber product has the characteristics of acid and alkali resistance and high temperature resistance, and actual requirements are met. In addition, the related preparation method is simple and convenient to operate, and does not need harsh conditions.

Description

Technical Field

[0001] The invention relates to a silicone rubber and a preparation method thereof, in particular to an acid-, alkali-, and high-temperature-resistant room-temperature-vulcanized silicone rubber and a preparation method thereof, belonging to the technical field of silicone rubber. Background Art

[0002] With the development and progress of science and technology, integrated stoves and integrated ovens have emerged, requiring the adhesive sealant of their frames or internal structural components to have better high temperature resistance, be able to withstand high temperature conditions of 300°C for a short time, and have acid and alkali resistance (withstand long-term aging in acid and alkali environments such as oil smoke, food, detergents, cleaning agents, etc.). In addition, in order to improve production efficiency, the adhesive sealant is required to be basically cured in a short time to form initial adhesion.

[0003] In the field of traditional household kitchen appliances, the mainstream is the one-component alcohol-type room temperature vulcanized sealant, which is mainly used as an adhesive sealant in this field because of its non-toxic, non-irritating and human-friendly characteristics; and in order to reduce the cost of silicone rubber, calcium carbonate is usually used as a reinforcing filler in the silicone rubber system. However, the curing rate of the one-component dealcoholized room temperature vulcanized silicone rubber is slow, and the bonded parts usually need to be placed for 24 hours before they can be moved slightly, which seriously affects the processing and production efficiency. In addition, the silicone rubber contains a large amount of calcium carbonate and is difficult to withstand the corrosion of acidic substances. In addition, the high temperature resistance of the commercially available one-component dealcoholized room temperature vulcanized silicone rubber can only withstand a high temperature environment below 180°C for a long time, and can withstand a high temperature environment of 260°C instantly.

[0004] The prior art "CN101638518 A kind of acid gas corrosion resistant high temperature resistant room temperature vulcanized silicone rubber and its manufacturing method", "CN1037353C high temperature resistant (350℃) room temperature vulcanized silicone rubber", "CN109593465A A kind of room temperature curing high temperature resistant organic silicone rubber material and its preparation method and application" and "CN109593464A A kind of room temperature curing high temperature resistant organic silicone rubber coating, preparation method and application" all involve silicone rubber, but do not solve the problem of alkali resistance or acid and alkali resistance, and the cross-linking agent involved is mainly silazane polymer, which is a non-normal commercial product (currently, the market price is more than 10,000 yuan / kg), which is not conducive to the industrial production needs of the product. In addition, for deacetone type silicone rubber (such as: CN101928462A, CN103044922A, etc.), it is a single-component room temperature vulcanized silicone rubber, which does not solve the problem of high temperature resistance, and does not meet the requirement of forming initial adhesion in half an hour.

[0005] Therefore, there is an urgent need to develop a room temperature vulcanized silicone rubber and a preparation method that can quickly and deeply cure, form adhesion within half an hour, and is resistant to acid, alkali, and high temperature. Summary of the invention

[0006] In order to solve the problems of the prior art, the present invention proposes an acid-alkali-resistant and high-temperature-resistant room temperature vulcanized silicone rubber and a preparation method thereof. In this technical solution, a,w-dihydroxy polydimethylphenylsiloxane (commonly known as 108 glue), a heat-resistant additive (neutral additive) treated with silazane, fumed silica treated with silazane, silicon micropowder, etc. are used in combination to ensure that the silicone rubber product has the characteristics of acid-alkali resistance and high temperature resistance to meet actual needs.

[0007] In order to achieve the above technical objectives, the following technical solutions are proposed:

[0008] The first purpose of the technical scheme is to propose: an acid-base-resistant and high-temperature-resistant room temperature vulcanized silicone rubber, comprising component A and component B mixed in a mass ratio of 10:1, component A comprising 100 parts of a,w-dihydroxy polydimethylphenylsiloxane (commonly known as "108 glue"), 10-20 parts of white carbon black, 30-40 parts of silicon powder and 2-5 parts of heat-resistant additives;

[0009] Component B includes 100 parts of dimethyl silicone oil, 200 parts of black paste, 100-150 parts of crosslinking agent, 25-50 parts of coupling agent and 15-25 parts of catalyst;

[0010] The structural formula of the a,w-polydimethylphenylsiloxane is:

[0011]

[0012] Among them, m+n=300~1000, m / n is 5 / 95~10 / 90.

[0013] Preferably, in the component A, the white carbon black is a fumed white carbon black treated with silazane, and its specific surface area is 150 m 2 / g. The conventional treatment process of fumed silica treated with silazane is a conventional treatment process, in which silazane can easily treat silica deeply, which can greatly reduce the silanol group on the surface of silica, thereby ensuring the high temperature resistance of silicone rubber.

[0014] Preferably, in the component A, the silicon powder is molten silicon powder with an average particle size of 10 to 20 μm.

[0015] Preferably, in the component A, the heat-resistant additive is a mixture of nano titanium dioxide and nano ferric oxide treated with silazane, the average particle size of both is 20 to 30 nm, and the mass ratio of the two is 1 / 3 to 3 / 1; the silazane treatment includes:

[0016] 1) Take 20g of a mixture of nano titanium dioxide and nano ferric oxide, place it in a 200ml solution of ethanol and water in a mass ratio of 1:1, stir it thoroughly (0.5h), test the pH value of the solution, usually the pH value is in the range of 3.5 to 4.5, then add sodium hydroxide to adjust the pH of the solution to 7.0, finally, filter the solution, take the filter cake and dry it in an oven at 150°C for 2h to obtain a dry mixed metal powder;

[0017] 2) Then, the dried mixed metal powder is dispersed in a mixed solvent of toluene and silazane (190 g toluene + 10 g silazane), stirred at room temperature for 30 min, and finally, the solvent is filtered to obtain a metal powder treated with silazane; dried, fully ground, and uniformly dispersed nano-metal mixed powder is obtained, which is a heat-resistant additive;

[0018] In order to ensure that silicone rubber has excellent heat resistance, special treatment with heat-resistant additives is carried out.

[0019] Preferably, in the component B, the silicone oil is polydimethylsiloxane, and the viscosity is 50 to 350 mPa·s at a temperature of 25°C.

[0020] Preferably, in the B component, the black paste is a carbon black slurry, which is a uniform dispersion of dimethyl silicone oil and carbon black.

[0021] Preferably, in the component B, the crosslinking agent is one of methyl triisopropenyloxy silane, vinyl triisopropenyloxy silane and phenyl triisopropenyloxy silane, or a mixture of any two or more thereof. More preferably, the crosslinking agent is phenyl triisopropenyloxy silane.

[0022] Preferably, in the B component, the coupling agent is one or a mixture of any two or more of γ-aminopropyltriethoxysilane (KH550), γ-glycidyloxypropyltrimethoxysilane (KH560), N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH792) and γ-chloropropyltriethoxysilane (I-31).

[0023] Preferably, in the B component, the catalyst is tetramethylguanidine propyl trimethoxysilane or tetramethylguanidine propyl triethoxysilane.

[0024] The second purpose of the technical solution is to propose: a method for preparing acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber, comprising the following steps:

[0025] Preparation of component A: Weigh a, w-dihydroxy polydimethylphenylsiloxane, white carbon black, silicon powder and heat-resistant additives respectively, add them into a planetary mixer, stir for 60 minutes under the conditions of vacuum degree of -0.080 to -0.092Mpa and rotation speed of 20 to 50rpm, and mix them evenly;

[0026] Preparation of component B: Weigh dimethyl silicone oil, black paste, crosslinking agent, coupling agent and catalyst respectively, add them into a planetary mixer, stir for 60 minutes under the conditions of vacuum degree of -0.080 to -0.092 MPa and rotation speed of 20 to 50 rpm to mix evenly;

[0027] Finally, mix component A and component B at a mass ratio of 10:1 quickly and evenly before use.

[0028] In this technical solution, the mechanism for ensuring that the silicone rubber has the properties of acid, alkali and high temperature resistance includes:

[0029] Firstly, the base polymer uses terminal hydroxyl polydimethylphenylsiloxane (108 glue), not the commonly used terminal hydroxyl polydimethylsiloxane (107 glue) on the market. Based on the base polymer structure, the high temperature resistance of silicone rubber can be effectively improved;

[0030] Secondly, heat-resistant additives (neutral additives) treated with silazane are used to avoid degradation of the silicone rubber main chain at high temperatures due to its acidity, thereby further improving the high temperature resistance of silicone rubber.

[0031] Finally, fumed silica treated with silazane and silica powder are used together as reinforcing fillers to avoid the problem of silicone rubber being intolerant to acid and alkali due to the filler being intolerant to acid and alkali. Moreover, after the fumed silica is deeply treated with silazane, most of the silanol groups on the surface of silica are replaced by silazane, which slows down the problem of degradation of the main chain of silicone rubber at high temperature caused by the hydroxyl groups on the surface of silica. Among them, the degradation reaction of the main chain of silicone rubber caused by silica involves the following:

[0032]

[0033] The beneficial technical effects brought about by adopting this technical solution are:

[0034] 1. In the present invention, a,w-dihydroxy polydimethylphenylsiloxane (commonly known as 108 glue), heat-resistant additives (neutral additives) treated with silazane, fumed silica treated with silazane, silicon powder, etc. are used in combination to ensure that the silicone rubber product has the characteristics of acid and alkali resistance and high temperature resistance to meet actual needs. The two-component vulcanization system is used to enable the silicone rubber to form good adhesion with the bonding substrate (within 0.5h), and ensure better initial adhesion, thereby improving production efficiency.

[0035] Component A of the two-component room temperature vulcanized silicone rubber involved in the present invention contains water. After components A and B are fully mixed, they can quickly undergo a cross-linking reaction under the action of water to quickly form a network structure. In this way, the silicone rubber can have good mechanical properties and bonding properties in a short time. However, the single-component room temperature vulcanized silicone rubber in the prior art relies on moisture in the air and cures slowly from the surface to the inside. It usually takes 24 hours to cure a thickness of 2 to 3 mm, that is, the curing rate is slow, and it is difficult to form initial adhesion to the adhesive material in a short time;

[0036] 2. In the present invention, terminal hydroxyl polydimethylphenylsiloxane is used as the base polymer. Based on the structure of the base polymer, the high temperature resistance of silicone rubber can be effectively improved. At the same time, phenyl triisopropenyloxysilane and the like are used as crosslinking agents. The hydrolysis activity of the crosslinking agent is better than that of tetraethyl orthosilicate, and the crosslinked network structure formed with the base polymer 108 glue is more stable. It requires higher energy to destroy its crosslinked network structure. Therefore, the high temperature resistance is better, thereby ensuring the performance of the silicone rubber. In addition, the by-product formed by the condensation of the crosslinking agent and 108 glue is acetone, which does not have a hydroxyl structure, thereby avoiding the degradation reaction of the silicone rubber main chain caused by hydroxyl groups under high temperature conditions, thereby reducing the high temperature resistance of silicone rubber. Traditional two-component condensation silicone rubber basically uses the crosslinking agent tetraethyl orthosilicate, and the by-product of the crosslinking reaction is ethanol (with a hydroxyl structure). Therefore, its high temperature resistance is poor.

[0037] 3. In the present invention, fumed silica treated with silazane and silicon powder are used in combination as reinforcing fillers to avoid the problem of silicone rubber being intolerant to acid and alkali due to the filler being intolerant to acid and alkali. Moreover, after the fumed silica is deeply treated with silazane, most of the silanol groups on the surface of silica are replaced by silazane, which alleviates the problem of degradation reaction of the main chain of silicone rubber at high temperature caused by the hydroxyl groups on the surface of silica.

[0038] Fourth, in the present invention, nano-metal mixed powder treated with silazane is used as a heat-resistant additive (neutral additive). On the one hand, the heat-resistant additive is neutral, which can avoid the acidity problem and promote the degradation of the main chain of silicone rubber at high temperature; on the other hand, its surface is treated with silazane to remove most of the hydroxyl groups on the surface. Similarly, the main chain degradation reaction of silicone rubber at high temperature caused by the hydroxyl groups on the surface of the additive is avoided, and the high temperature resistance of silicone rubber is further improved;

[0039] 5. In the present invention, the catalyst selected is tetramethylguanidine propyl trimethoxysilane or tetramethylguanidine propyl triethoxysilane, rather than the traditional dibutyltin dilaurate (organic tin catalyst). The organotin catalyst can make the silicone rubber "revert to its original state" under high temperature conditions, which is specifically manifested as: the cross-linked network structure of the silicone rubber is decomposed, causing the mechanical properties of the silicone rubber to drop sharply, and the silicone rubber surface becomes "sticky". The present invention avoids the problem of performance attenuation of silicone rubber under high temperature conditions by further selecting the specific type of catalyst, thereby improving the high temperature resistance of silicone rubber;

[0040] 6. In the present invention, a method for preparing acid-, alkali-, and high-temperature-resistant room-temperature vulcanized silicone rubber is provided. The method is simple and easy to operate without requiring harsh process conditions, and meets the requirements of industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a result diagram of conventional silicone rubber (brand GD-883, batch number: SX-23-110) in the prior art immersed in a 10% glacial acetic acid aqueous solution at 60°C for 5 minutes;

[0042] Figure 2 The comparison results of the silicone rubber in Example 1 of the present invention and the conventional silicone rubber in the prior art after being immersed in a 10% glacial acetic acid aqueous solution at 60° C. for 5 minutes are shown in Figure 1 (A is the silicone rubber in Example 1; B is a commercially available product, brand GD-453, batch number: SX-23-072);

[0043] Figure 3 This is a result diagram of conventional silicone rubber (brand name: GD-6941 / 1108C, batch number: SX-23-144) in the prior art immersed in a 10% sodium hydroxide aqueous solution at 60°C for 24 hours;

[0044] Figure 4 This is a graph showing the result of the silicone rubber in Example 1 of the present invention being immersed in a 10% sodium hydroxide aqueous solution at 60° C. for 24 hours. DETAILED DESCRIPTION

[0045] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the following embodiments, the structural formula of the a,w-polydimethylphenylsiloxane involved is:

[0047]

[0048] Example 1

[0049] This embodiment provides an acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber, and the formula involved is shown in Table 1 below;

[0050] Table 1

[0051]

[0052] The above components A and B are dispersed evenly in a planetary mixer at a vacuum degree of -0.080Mpa and a rotation speed of 20rpm, and stirred for 60 minutes; finally, component A and component B are quickly mixed at a mass ratio of 10:1 and then can be used.

[0053] Example 2

[0054] This embodiment provides an acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber, and the formula involved is shown in Table 2 below;

[0055] Table 3

[0056]

[0057] The above-mentioned components A and B are dispersed evenly in a planetary mixer at a vacuum degree of -0.080Mpa and a rotation speed of 30rpm, and stirred for 60 minutes; finally, component A and component B are quickly mixed evenly at a mass ratio of 10:1, and then they can be used.

[0058] Example 3

[0059] This embodiment provides an acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber, and the formula involved is shown in Table 3 below;

[0060] Table 3

[0061]

[0062] The above-mentioned components A and B are dispersed evenly in a planetary mixer at a vacuum degree of -0.080Mpa and a rotation speed of 40rpm, and stirred for 60 minutes; finally, component A and component B are quickly mixed at a mass ratio of 10:1 and can be used.

[0063] Example 4

[0064] This embodiment provides an acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber, and the formula involved is shown in Table 4 below;

[0065] Table 4

[0066]

[0067] The above-mentioned components A and B are dispersed evenly in a planetary mixer at a vacuum degree of -0.080Mpa and a rotation speed of 45rpm, and stirred for 60 minutes; finally, component A and component B are quickly mixed at a mass ratio of 10:1 and can be used.

[0068] Example 5

[0069] This embodiment provides an acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber, and the formula involved is shown in Table 5 below;

[0070] Table 5

[0071]

[0072] The above-mentioned components A and B are dispersed evenly in a planetary mixer at a vacuum degree of -0.090Mpa and a rotation speed of 50rpm, and stirred for 60 minutes; finally, component A and component B are quickly mixed evenly at a mass ratio of 10:1, and then they can be used.

[0073] Example 6

[0074] This embodiment provides an acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber, and the formula involved is shown in Table 6 below;

[0075] Table 6

[0076]

[0077]

[0078] The above-mentioned components A and B are dispersed evenly in a planetary mixer at a vacuum degree of -0.092Mpa and a rotation speed of 37rpm, and stirred for 60 minutes; finally, component A and component B are quickly mixed evenly at a mass ratio of 10:1, and then they can be used.

[0079] Comparative Example 1

[0080] On the basis of Example 1, this comparative example provides a vulcanized silicone rubber (the formula involved is shown in Table 7 below), wherein the crosslinking agent in component B is tetraethyl orthosilicate and the catalyst is organic tin; this is used as a comparative example of Example 1 to further illustrate the present invention.

[0081] Table 7

[0082]

[0083] The above components A and B are dispersed evenly in a planetary mixer at a vacuum degree of -0.080Mpa and a rotation speed of 20rpm, and stirred for 60 minutes; finally, component A and component B are quickly mixed at a mass ratio of 10:1 and then can be used.

[0084] Comparative Example 2

[0085] On the basis of Example 1, this comparative example provides a vulcanized silicone rubber (the formula involved is shown in Table 8 below), wherein the additive in component B is a mixture of original metal powders of titanium oxide / iron oxide = 1 / 3 (i.e., not treated with silazane); this is used as a comparative example of Example 1 to further illustrate the present invention.

[0086] Table 8

[0087]

[0088]

[0089] The above components A and B are dispersed evenly in a planetary mixer at a vacuum degree of -0.080Mpa and a rotation speed of 20rpm, and stirred for 60 minutes; finally, component A and component B are quickly mixed at a mass ratio of 10:1 and then can be used.

[0090] Comparative Example 3

[0091] On the basis of Example 1, without changing the original formula ratio, component A is treated by heating to remove moisture to prepare a basic paste of a one-component room temperature vulcanized silicone rubber; then, additives are added to the basic paste in sequence to prepare a one-component deacetone type room temperature vulcanized silicone rubber (the formula involved is shown in Table 9 below), wherein the basic paste is calculated as 100 parts by mass and the additives are added in 10 parts by mass; this is used as a comparative example of Example 1 to further illustrate the present invention.

[0092] Table 9

[0093]

[0094] The preparation method involved is as follows:

[0095] 1) Stir the raw materials of the above-mentioned basic paste evenly under the conditions of a vacuum degree of -0.080Mpa and a rotation speed of 20rpm for 60min to obtain a paste; 2) Then, place the paste in a high-speed disperser, heat to 160°C, dehumidify and dry for half an hour, and after the paste is cooled, place it in a planetary mixer; 3) In the planetary mixer, add additives (dimethyl silicone oil, black paste, cross-linking agent, coupling agent and catalyst) in sequence every half an hour, and maintain a vacuum degree of -0.080Mpa throughout the process. After the materials are added, stir for another half an hour. The stirring rate of the whole process is controlled at 20rpm, and then discharge the material into a 300ml plastic tube and use it after extrusion.

[0096] The silicone rubber obtained by the above Examples 1-6 and Comparative Examples 1-3 was tested by the following methods: tensile strength and elongation at break (tested according to GB / T 528-2009), hardness (tested according to GB / T 531-2008), shear strength (tested according to GB / T7124-2008) and hot air accelerated aging (tested according to GB / T 3512-2001). The product performance is shown in Table 10 below.

[0097] Table 10 Silicone rubber test results are as follows

[0098]

[0099] From Table 10, we can see that:

[0100] (1) After being soaked in acid and alkali for 24 hours, the hardness, tensile strength and elongation at break of the silicone rubber obtained in Examples 1-6 can be maintained at more than 75% of the original values, and the shear strength after half an hour is greater than 0.5 MPa, indicating that the silicone rubber has good acid and alkali resistance, and after half an hour, the silicone rubber forms good initial adhesion with the bonding substrate. However, in Comparative Example 3 (a single-component deacetone-type room temperature vulcanized silicone rubber made from the raw materials of Example 1), its shear strength after half an hour is only 0.12 MPa, which is in an uncured state, that is, it does not have good initial adhesion in a short time, and after aging at high temperature of 315℃*4h, the mechanical properties and hardness values ​​are much lower than those of the silicone rubber in Example 1;

[0101] (2) By comparing Example 1 with Comparative Example 1, it can be found that after high-temperature aging at 315°C*4h, the silicone rubber prepared by the crosslinking agent used in Example 1 and the silicone rubber prepared by the crosslinking agent used in Comparative Example 1 have a tensile strength retention value of 77.4% (2.65 / 3.42) and a hardness retention value of 82.2% (37 / 45) of the silicone rubber in Example 1, which are much higher than the tensile strength retention value of 49.7% (1.64 / 3.30) and the hardness retention value of 58.1% (25 / 43) of the silicone rubber in Comparative Example 1, indicating that the silicone rubber prepared by the crosslinking agent in Example 1 has better high-temperature resistance than the crosslinking agent (ethyl orthosilicate) used in the traditional two-component silicone rubber;

[0102] (3) By comparing Example 1 with Comparative Example 2, it can be found that: under normal conditions and acid-alkali resistant environmental conditions, the mechanical properties of the silicone rubbers of the two are basically the same. However, after high-temperature aging at 315°C*4h, it is found that the hardness of the silicone rubber in Example 1 is 37HA, the tensile strength is 2.65MPa, and the elongation is 86%, which are significantly higher than the hardness of the silicone rubber in Comparative Example 2, which is 31HA, the tensile strength is 2.01MPa, and the elongation is 72%, indicating that the treated metal powder as a heat-resistant additive is beneficial to the high-temperature resistance of the silicone rubber.

[0103] Comparative Example 4

[0104] On the basis of Example 1, in this comparative example, the silicone rubber obtained in Example 1 and the silicone rubber in the prior art (brand GD-883, a conventional room temperature vulcanized silicone rubber product, the manufacturer is Zhonglan Chemical Research and Design Institute Co., Ltd. Xinjin Branch, batch number: SX-23-110; brand GD-453, a conventional commercial silicone rubber product, the manufacturer is Zhonglan Chemical Research and Design Institute Co., Ltd. Xinjin Branch, batch number: SX-23-072; brand GD-6941 / 1108C, a commercially available two-component room temperature vulcanized silicone rubber conventional product, the manufacturer is Zhonglan Chemical Research and Design Institute Co., Ltd. Xinjin Branch, batch number: SX-23-144), respectively, were immersed in a 60°C, 10% glacial acetic acid aqueous solution for 5 min, and immersed in a 60°C, 10% sodium hydroxide aqueous solution for 24 h, and the results were as follows: Figure 1-4 shown.

[0105] Depend on Figure 1 It can be seen that after the conventional silicone rubber (brand GD-883, batch number: SX-23-110) in the prior art is immersed in a 10% glacial acetic acid aqueous solution at 60°C for 5 minutes, bubbles are continuously generated on the surface of the silicone rubber;

[0106] Depend on Figure 2 It can be seen that after the conventional silicone rubber (brand GD-453, batch number: SX-23-072) in the prior art is immersed in a 10% glacial acetic acid aqueous solution at 60°C for 5 minutes, bubbles are continuously generated on the surface of the silicone rubber; while after the silicone rubber obtained in Example 1 is immersed in a 10% glacial acetic acid aqueous solution at 60°C for 5 minutes, no bubbles are generated on the surface of the silicone rubber;

[0107] Depend on Figure 3 It can be seen that after the conventional silicone rubber (brand name GD-6941 / 1108C, batch number SX-23-144) in the prior art is immersed in a 10% sodium hydroxide aqueous solution at 60°C for 24 hours, the silicone rubber swells, rolls inward, and the surface becomes sticky;

[0108] Depend on Figure 4 It can be seen that after the silicone rubber obtained in Example 1 is immersed in a 10% sodium hydroxide aqueous solution at 60°C for 24 hours, the silicone rubber does not swell or become sticky, and maintains its original morphology;

[0109] In summary, it can be seen that the silicone rubber product in the present invention has the characteristics of acid and alkali resistance and high temperature resistance.

[0110] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A room temperature vulcanized silicone rubber that is resistant to acid, alkali and high temperature, characterized in that: It comprises component A and component B mixed in a mass ratio of 10:1, wherein component A comprises 100 parts of a,w-dihydroxy polydimethylphenylsiloxane, 10-20 parts of white carbon black, 30-40 parts of silicon micropowder and 2-5 parts of heat-resistant additives; Component B includes 100 parts of dimethyl silicone oil, 200 parts of black paste, 100-150 parts of crosslinking agent, 25-50 parts of coupling agent and 15-25 parts of catalyst; The structural formula of the a,w-polydimethylphenylsiloxane is: ； Among them, m+n=300~1000, and m / n is 5 / 95~10 / 90.

2. The acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber according to claim 1, characterized in that: In the component A, the white carbon black is a fumed white carbon black treated with silazane, and the specific surface area is 150 m 2 / g.

3. The acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber according to claim 1, characterized in that: In the component A, the silicon powder is molten silicon powder with an average particle size of 10 to 20 μm.

4. The acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber according to claim 1, characterized in that: In the component A, the heat-resistant additive is a mixture of nano titanium dioxide and nano ferric oxide treated with silazane, the average particle size of the nano titanium dioxide and the nano ferric oxide is 20-30 nm, and the mass ratio of the nano titanium dioxide to the nano ferric oxide is 1 / 3-3 / 1; the silazane treatment includes: 1) Take 20g of a mixture of nano titanium dioxide and nano ferric oxide, place it in 200ml of a solution of ethanol and water in a mass ratio of 1:1, stir until uniform, adjust the pH to 7.0, filter, and dry the filter cake to obtain a dry mixed metal powder; 2) Then, the dried mixed metal powder is dispersed in a mixed solvent of toluene and silazane, mixed, filtered to remove the solvent, and the metal powder treated with silazane is obtained; dried, ground, and uniformly dispersed nano-metal mixed powder is obtained, which is the heat-resistant additive; Wherein, in the mixed solvent of toluene and silazane, the mass ratio of toluene to silazane is 19:

1.

5. The acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber according to claim 1, characterized in that: In the component B, the dimethyl silicone oil is polydimethylsiloxane, and the viscosity is 50 to 350 mPa•s at a temperature of 25°C.

6. The acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber according to claim 1, characterized in that: In the B component, the black paste is a carbon black slurry, which is a uniform dispersion of dimethyl silicone oil and carbon black.

7. The acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber according to claim 1, characterized in that: In the component B, the crosslinking agent is one or a mixture of any two or more of methyl triisopropyleneoxysilane, vinyl triisopropyleneoxysilane and phenyl triisopropyleneoxysilane.

8. The acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber according to claim 1, characterized in that: In the B component, the coupling agent is one or a mixture of any two or more of γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-chloropropyltriethoxysilane.

9. The acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber according to claim 1, characterized in that: In the B component, the catalyst is tetramethylguanidine propyl trimethoxysilane or tetramethylguanidine propyl triethoxysilane.

10. A method for preparing the acid-, alkali-, and high-temperature-resistant room temperature vulcanized silicone rubber according to any one of claims 1 to 9, characterized in that: The steps include: Preparation of component A: Weigh a, w-dihydroxy polydimethylphenylsiloxane, white carbon black, silicon powder and heat-resistant additives respectively, add them into a planetary mixer, stir for 60 minutes under the conditions of vacuum degree of -0.080 to -0.092Mpa and rotation speed of 20 to 50rpm, and mix them evenly; Preparation of component B: Weigh dimethyl silicone oil, black paste, crosslinking agent, coupling agent and catalyst respectively, add them into a planetary mixer, stir for 60 minutes under the conditions of vacuum degree of -0.080 to -0.092 MPa and rotation speed of 20 to 50 rpm to mix evenly; Finally, component A and component B are mixed evenly in a mass ratio of 10:1 to obtain the product.

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