Flame-retardant mildew-proof organic silica gel and preparation method thereof

Abstract

The invention discloses flame-retardant and mildew-proof organic silica gel and a preparation method thereof, and relates to the technical field of organic silica gel. The coating is prepared from the following components in parts by weight: 53 to 62 parts of hydroxyl-terminated polysiloxane, 7 to 10 parts of fumed silica, 1 to 3 parts of a flame retardant, 5 to 13 parts of precipitated white carbon black, 2 to 7 parts of color paste, 2 to 5 parts of a coupling agent, 0.4 to 1.5 parts of a composite titanide, 3 to 8 parts of a cross-linking agent, 1 to 3 parts of a toughening agent, 0.1 to 0.4 part of a mildew preventive and 0.5 to 2.5 parts of silicone oil. The flame-retardant mildew-proof organic silica gel prepared by the invention has excellent flame-retardant property and mildew-proof property, the flame-retardant property reaches UL94V-0 level, the mildew-proof property reaches 0 level (no mildew), and the flame-retardant mildew-proof organic silica gel is high in colloid curing speed, good in construction performance, environment-friendly and free of toxic and side effects on human bodies, and has wide application prospects in the fields of electronic and electrical appliances, building fire prevention, moisture and mildew prevention and the like.

Description

Technical Field

[0001] This invention relates to the field of silicone technology, and in particular to a flame-retardant and mildew-resistant silicone and its preparation method. Background Technology

[0002] As an important class of polymer materials, silicone adhesives are widely used in many key fields such as aviation, aerospace, marine, military, nuclear energy, and electronics industries due to their properties such as high temperature resistance, stable adhesion, and good durability. With the continuous expansion of its application scope, from basic surface sealing and bonding of glass, metal sheets, and plastic sheets to bonding surfaces with many irregularities and different processing techniques, the application of silicone adhesives is moving from conventional to specialized.

[0003] In terms of flame retardancy, silicone currently suffers from serious defects. In the electronics and electrical industry, silicone used for potting and sealing electronic components inside equipment often has poor flame retardancy, leading to large-scale losses in the event of a fire. In the construction sector, insufficient flame retardancy makes it difficult to effectively prevent the spread of fire through building gaps or insulation layers during a fire. Anti-mold properties are also a major weakness of existing silicone products. In modern residences, silicone, commonly used as a sealing material in interior decoration, such as single-component room temperature vulcanizing silicone rubber, is highly susceptible to mold growth in humid environments. Mold gradually erodes the silicone structure, damages the molecular chains, and reduces its physical properties.

[0004] In related technologies, although a flame-retardant room temperature vulcanizing silicone rubber formulation and flame-retardant room temperature vulcanizing silicone rubber are disclosed, the silicone rubber has good flame retardancy and mechanical properties after vulcanization. However, it is prone to mold and bacteria growth when used in some humid environments, which may cause harm to human health.

[0005] Therefore, it is urgent to develop an organosilicon with excellent flame-retardant and mildew-resistant properties. This will not only improve the service life and reliability of products and reduce economic losses caused by fire and mildew, but also create a safer and healthier living and working environment for people, meeting the urgent needs of social development. Summary of the Invention

[0006] The purpose of this invention is to provide a flame-retardant and mildew-resistant silicone rubber and its preparation method, thereby solving the problems of poor flame retardancy and easy mildew in current silicone rubber products.

[0007] To achieve the above objectives, the present invention provides a flame-retardant and mildew-resistant silicone rubber, comprising, by weight: 53-62 parts of hydroxyl-terminated polysiloxane, 7-10 parts of fumed silica, 1-3 parts of flame retardant, 5-13 parts of precipitated silica, 2-7 parts of color paste, 2-5 parts of coupling agent, 0.4-1.5 parts of composite titanium compound, 3-8 parts of crosslinking agent, 1-3 parts of toughening agent, 0.1-0.4 parts of mildew inhibitor, and 0.5-2.5 parts of silicone oil.

[0008] Preferably, the hydroxyl-terminated polysiloxane is α,ω-dihydroxypolydimethylsiloxane.

[0009] Preferably, the particle size of the fumed silica is 7 nm to 40 nm.

[0010] Preferably, the color paste is at least one selected from carbon black, titanium dioxide, iron oxide red, phthalocyanine blue, and phthalocyanine green.

[0011] Preferably, the composite titanium compound is a mixture of tetraisopropyl titanate and bis(acetylacetonyl)diisopropyl titanate; the weight ratio of the tetraisopropyl titanate to the bis(acetylacetonyl)diisopropyl titanate is 1:0.25-1.

[0012] Preferably, the toughening agent is γ-methacryloxypropyltrimethoxysilane-modified hollow glass microspheres. As a toughening agent, γ-methacryloxypropyltrimethoxysilane-modified hollow glass microspheres can be uniformly dispersed in the matrix, significantly improving compatibility with the silicone rubber matrix (hydroxyl-terminated polysiloxane), enhancing toughness, significantly increasing the tensile strength of silicone rubber, and improving the overall physical properties of silicone rubber.

[0013] Preferably, the flame retardant is at least one of decabromodiphenyl ethane and decabromodiphenyl ether; the mildew inhibitor is at least one of nano-silver powder and nano-zinc oxide. The flame retardant is preferably a bromine-based flame retardant, which can first decompose at high combustion temperatures to generate bromine free radicals. These free radicals capture hydrogen and hydroxyl radicals, key components of the combustion chain reaction, thus interrupting combustion and assisting the silicone rubber in forming a dense carbonized layer to isolate heat and oxygen, ultimately achieving a good flame retardant effect. γ-methacryloyloxypropyltrimethoxysilane-modified hollow glass microspheres, when combined with a nano-mildew inhibitor, can reduce the surface energy of silicone and the adhesion rate of microorganisms. Furthermore, because the nano-mildew inhibitor continuously releases antibacterial components, it can extend the service life of silicone rubber in harsh environments.

[0014] Preferably, the coupling agent is at least one selected from methyltriethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane; and the crosslinking agent is at least one selected from γ-chloropropyltriethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, and tetraethyl orthosilicate.

[0015] This invention also provides a method for preparing flame-retardant and mildew-resistant silicone rubber, comprising the following steps:

[0016] S1. By weight, add hydroxyl-terminated polysiloxane, color paste, fumed silica and silicone oil into a planetary mixer and stir for 30 min to 120 min under a vacuum of 0.09 MPa and a rotation speed of 25 rpm to 60 rpm to obtain the first mixture; the fumed silica needs to be dried in an oven at 90℃ to 150℃ for 5 h before being added to the planetary mixer;

[0017] S2. Add precipitated silica, flame retardant and mildew inhibitor to the first mixture, and stir for 30 min to 120 min under vacuum of 0.09 MPa and rotation speed of 25 rpm to 35 rpm to obtain the second mixture.

[0018] S3. Prepare a toughening agent, then add the toughening agent, crosslinking agent, composite titanium compound and coupling agent to the second mixture, and stir for 45min to 120min under vacuum of 0.09MPa and rotation speed of 25rpm to 60rpm to obtain the finished product, namely flame-retardant and mildew-proof silicone.

[0019] Preferably, the method for preparing the toughening agent includes the following steps:

[0020] (1) Dissolve γ-methacryloxypropyltrimethoxysilane in anhydrous ethanol to prepare a coupling agent solution with a mass fraction of 1% to 3%; use anhydrous ethanol as a solvent to dissolve γ-methacryloxypropyltrimethoxysilane to prepare a solution with a mass fraction of 1% to 3%.

[0021] (2) Add the clean microbeads to the above solution at a mass ratio of 1:5 to 10 and stir the reaction at 40℃ to 60℃ and 150 rpm to 200 rpm for 2 to 3 hours to obtain the condensation reaction solution.

[0022] (3) The condensation reaction solution was centrifuged and washed 2 to 3 times with anhydrous ethanol, and then vacuum dried at 60℃ to 80℃ for 3 to 4 hours to obtain activated microbeads.

[0023] (4) Disperse titanium dioxide and zinc oxide nanoparticles in water to prepare a suspension with a solid content of 5% to 8%, then add sodium polyacrylate and disperse at high speed of 3000 rpm to 4000 rpm for 30 min to 40 min to obtain a coating solution; the amount of sodium polyacrylate added is 0.5% to 1% of the total mass of the coating solution.

[0024] (5) Immerse the activated microspheres in the coating solution, and after 10 min to 15 min, pull them up at a speed of 2 cm / min to 3 cm / min to form a film. Then dry them at 80℃ to 100℃ for 1 h to 2 h and calcine them at 400℃ to 500℃ for 2 h to 3 h to obtain hollow glass microspheres modified with γ-methacryloyloxypropyltrimethoxysilane, i.e. toughening agent.

[0025] In summary, the flame-retardant and mildew-resistant silicone rubber and its preparation method provided by this invention have the following advantages compared to traditional technologies:

[0026] This invention relates to a flame-retardant and mildew-resistant silicone rubber prepared from hydroxyl-terminated polysiloxane, fumed silica, flame retardant, precipitated silica, color paste, coupling agent, composite titanium compound, crosslinking agent, toughening agent, mildew inhibitor, and silicone oil. It possesses excellent flame-retardant and mildew-resistant properties, achieving a UL94 V-0 flame-retardant rating and a mildew-resistant rating of 0 (no mildew growth). The addition of the toughening agent significantly improves tensile strength. Furthermore, the colloid cures quickly, exhibits good workability, is environmentally friendly, and has no toxic side effects on the human body. It has broad application prospects in many fields such as electronics, fire protection in buildings, and moisture and mildew prevention.

[0027] The technical method of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a flowchart of a method for preparing a flame-retardant and mildew-resistant silicone rubber according to the present invention. Detailed Implementation

[0029] The technical method of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0031] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0032] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0033] The following are specific embodiments of a flame-retardant and mildew-resistant silicone rubber and its preparation method provided in this application:

[0034] Example 1

[0035] A flame-retardant and mildew-resistant silicone rubber compound, by weight, comprises: 53 parts α,ω-dihydroxypolydimethylsiloxane, 4 parts carbon black, 10 parts fumed silica, 2.5 parts silicone oil, 13 parts precipitated white carbon black, 3 parts decabromodiphenyl ethane, 0.1 parts nano silver powder, 1 part toughening agent, 8 parts γ-chloropropyltriethoxysilane, 0.4 parts composite titanium compound, and 5 parts methyltriethoxysilane. The composite titanium compound is a mixture of tetraisopropyl titanate and bis(acetylacetonate)diisopropyl titanate, with a weight ratio of 1:1 between the two.

[0036] A method for preparing flame-retardant and mildew-resistant silicone rubber, such as... Figure 1 As shown, it includes the following steps:

[0037] S1. Preparation of toughening agent, the specific steps are as follows:

[0038] (1) Dissolve γ-methacryloxypropyltrimethoxysilane in anhydrous ethanol to prepare a coupling agent solution with a mass fraction of 3%. Dissolve γ-methacryloxypropyltrimethoxysilane in anhydrous ethanol to prepare a solution with a mass fraction of 3%.

[0039] (2) The clean microbeads were added to the solution at a mass ratio of 1:5 and stirred at 40°C and 150 rpm for 3 hours to obtain the condensation reaction solution.

[0040] (3) The condensation reaction solution was centrifuged and washed three times with anhydrous ethanol and dried under vacuum at 60°C for 4 hours to obtain activated microbeads.

[0041] (4) Titanium dioxide and zinc oxide nanoparticles were dispersed in water to prepare a suspension with a solid content of 5%. Then, sodium polyacrylate was added and dispersed at 4000 rpm for 30 min to obtain the coating solution. The amount of sodium polyacrylate added was 0.5% of the total mass of the coating solution.

[0042] (5) Immerse the activated microspheres in the coating solution, and after 15 min, pull them up at a speed of 2 cm / min to form a film. Then dry them at 100℃ for 1 h and calcine them at 500℃ for 2 h to obtain hollow glass microspheres modified with γ-methacryloxypropyltrimethoxysilane, i.e. toughening agent.

[0043] S2. By weight, add 53 parts α,ω-dihydroxypolydimethylsiloxane, 4 parts carbon black, 10 parts fumed silica with a particle size of 40 nm, and 2.5 parts silicone oil into a planetary mixer and stir for 30 minutes under a vacuum of 0.09 MPa and a rotation speed of 25 rpm to obtain the first mixture. The fumed silica needs to be dried in an oven at 150°C for 5 hours before being added to the planetary mixer.

[0044] S3. Add 13 parts of precipitated white carbon black, 3 parts of decabromodiphenyl ethane and 0.1 parts of nano silver powder to the first mixture, and stir for 30 minutes under a vacuum of 0.09 MPa and a rotation speed of 25 rpm to obtain the second mixture.

[0045] S4. Add 1 part toughening agent, 8 parts γ-chloropropyltriethoxysilane, 0.4 parts composite titanium compound, and 5 parts methyltriethoxysilane to the second mixture. Stir for 45 minutes under a vacuum of 0.09 MPa and a rotation speed of 25 rpm to obtain the finished product, namely flame-retardant and mildew-proof silicone.

[0046] Example 2

[0047] A flame-retardant and mildew-resistant silicone rubber compound, by weight, comprises: 58 parts α,ω-dihydroxypolydimethylsiloxane, 3 parts titanium dioxide, 9 parts fumed silica, 1.1 parts silicone oil, 11 parts precipitated silica, 2 parts decabromodiphenyl ethane, 0.4 parts nano zinc oxide, 3 parts toughening agent, 8 parts methyltrimethoxysilane, 1.5 parts composite titanium compound, and 3 parts methyltriethoxysilane. The composite titanium compound is a mixture of tetraisopropyl titanate and bis(acetylacetonate)diisopropyl titanate, with a weight ratio of 1:0.25 between the two.

[0048] A method for preparing flame-retardant and mildew-resistant silicone rubber includes the following steps:

[0049] S1. Preparation of toughening agent, the specific steps are as follows:

[0050] (1) Dissolve γ-methacryloxypropyltrimethoxysilane in anhydrous ethanol to prepare a coupling agent solution with a mass fraction of 1% to 3%. Dissolve γ-methacryloxypropyltrimethoxysilane in anhydrous ethanol to prepare a solution with a mass fraction of 1%.

[0051] (2) The clean microbeads were added to the solution at a mass ratio of 1:10 and stirred at 60°C and 200 rpm for 2 hours to obtain the condensation reaction solution.

[0052] (3) The condensation reaction solution was centrifuged and washed twice with anhydrous ethanol, and then dried under vacuum at 80°C for 3 hours to obtain activated microbeads.

[0053] (4) Titanium dioxide and zinc oxide nanoparticles were dispersed in water to prepare a suspension with a solid content of 8%. Then, sodium polyacrylate was added and dispersed at 3000 rpm for 40 min to obtain the coating solution. The amount of sodium polyacrylate added was 1% of the total mass of the coating solution.

[0054] (5) Immerse the activated microspheres in the coating solution, and after 10 min, pull them up at a speed of 3 cm / min to form a film. Then dry at 80℃ for 2 h and calcine at 400℃ for 3 h to obtain hollow glass microspheres modified with γ-methacryloyloxypropyltrimethoxysilane, i.e. toughening agent.

[0055] S2. By weight, add 58 parts of α,ω-dihydroxypolydimethylsiloxane, 3 parts of titanium dioxide, 9 parts of fumed silica with a particle size of 7 nm, and 1.1 parts of silicone oil into a planetary mixer and stir for 120 minutes under a vacuum of 0.09 MPa and a rotation speed of 60 rpm to obtain the first mixture. The fumed silica needs to be dried in an oven at 90°C for 5 hours before being added to the planetary mixer.

[0056] S3. Add 11 parts of precipitated white carbon black, 2 parts of decabromodiphenyl ethane and 0.4 parts of nano zinc oxide to the first mixture, and stir for 120 min under a vacuum of 0.09 MPa and a rotation speed of 35 rpm to obtain the second mixture.

[0057] S4. Add 3 parts toughening agent, 3 parts methyltrimethoxysilane, 1.5 parts composite titanium compound and 8 parts vinyltriethoxysilane to the second mixture, and stir for 120 minutes under vacuum of 0.09 MPa and rotation speed of 60 rpm to obtain the finished product, namely flame retardant and mildew resistant silicone.

[0058] Example 3

[0059] A flame-retardant and mildew-resistant silicone rubber compound, by weight, comprises: 62 parts α,ω-dihydroxypolydimethylsiloxane, 2 parts phthalocyanine blue, 2 parts phthalocyanine green, 7.8 parts fumed silica, 0.5 parts silicone oil, 5 parts precipitated silica, 2 parts decabromodiphenyl ether, 1 part decabromodiphenyl ethane, 0.1 parts nano silver powder, 0.1 parts nano zinc oxide, 3 parts toughening agent, 4 parts vinyltrimethoxysilane, 3 parts phenyltrimethoxysilane, 1 part tetraethyl orthosilicate, 1.5 parts composite titanium compound, 2 parts γ-mercaptopropyltrimethoxysilane, and 3 parts vinyltriethoxysilane. The composite titanium compound is a mixture of tetraisopropyl titanate and bis(acetylacetonate)diisopropyl titanate, with a weight ratio of 1:0.5 between the two.

[0060] A method for preparing flame-retardant and mildew-resistant silicone rubber includes the following steps:

[0061] S1. Preparation of toughening agent, the specific steps are as follows:

[0062] (1) Dissolve γ-methacryloxypropyltrimethoxysilane in anhydrous ethanol to prepare a coupling agent solution with a mass fraction of 1% to 3%. Dissolve γ-methacryloxypropyltrimethoxysilane in anhydrous ethanol to prepare a solution with a mass fraction of 2%.

[0063] (2) The clean microbeads were added to the solution at a mass ratio of 1:8 and stirred at 50°C and 180 rpm for 1.5 h to obtain the condensation reaction solution.

[0064] (3) The condensation reaction solution was centrifuged and washed 2 to 3 times with anhydrous ethanol and dried under vacuum at 70°C for 3.5 h to obtain activated microbeads.

[0065] (4) Titanium dioxide and zinc oxide nanoparticles were dispersed in water to prepare a suspension with a solid content of 5% to 8%. Then, sodium polyacrylate was added and dispersed at 3500 rpm for 35 min to obtain the coating solution. The amount of sodium polyacrylate added was 0.8% of the total mass of the coating solution.

[0066] (5) Immerse the activated microspheres in the coating solution, and after 12 min, pull them up at a speed of 2.5 cm / min to form a film. Then dry at 90℃ for 1.5 h and calcine at 450℃ for 2.5 h to obtain hollow glass microspheres modified with γ-methacryloyloxypropyltrimethoxysilane, i.e. toughening agent.

[0067] S2. By weight, add 62 parts α,ω-dihydroxypolydimethylsiloxane, 2 parts phthalocyanine blue, 2 parts phthalocyanine green, 7 parts fumed silica with a particle size of 30 nm, and 0.5 parts silicone oil into a planetary mixer. Stir for 60 minutes under a vacuum of 0.09 MPa and a rotation speed of 45 rpm to obtain the first mixture. The fumed silica needs to be dried in an oven at 110°C for 5 hours before being added to the planetary mixer.

[0068] S3. Add 5 parts of precipitated white carbon black, 2 parts of decabromodiphenyl ethane, 1 part of decabromodiphenyl ether, 0.1 parts of nano silver powder, and 0.1 parts of nano zinc oxide to the first mixture. Stir for 85 minutes under a vacuum of 0.09 MPa and a rotation speed of 30 rpm to obtain the second mixture.

[0069] S4. Add 3 parts toughening agent, 4 parts vinyltrimethoxysilane, 3 parts phenyltrimethoxysilane, 1 part tetraethyl orthosilicate, 1.5 parts composite titanium compound, 2 parts γ-mercaptopropyltrimethoxysilane and 3 parts vinyltriethoxysilane to the second mixture, and stir for 95 minutes under a vacuum of 0.09 MPa and a rotation speed of 35 rpm to obtain the finished product, namely flame-retardant and mildew-proof silicone.

[0070] Comparative Example 1

[0071] Comparative Example 1 is a commercially available Dow Corning SE9184 flame-retardant and mildew-resistant silicone rubber.

[0072] Comparative Example 2

[0073] Comparative Example 2 is a commercially available Xinwei 388 flame-retardant silicone.

[0074] Performance testing

[0075] Five types of flame-retardant and mildew-resistant silicone sealants, prepared in Examples 1, 2, and 3 of this invention, along with commercially available Dow Corning SE9184 flame-retardant and mildew-resistant silicone sealant from Comparative Example 1 and Xinwei 388 flame-retardant silicone sealant from Comparative Example 2, were used as samples for performance testing. Samples were prepared according to the requirements of GB / T 14683-2017 "Silicone and Modified Silicone Building Sealants," and the performance testing methods are as follows:

[0076] 1. Surface drying time: Refer to the provisions of GB / T 13477.3-2017 "Test methods for building sealing materials - Part 3: Method for determining the extrudability of sealing materials using standard instruments".

[0077] 2. Flame retardant performance: According to GB / T 2408-2008 "Determination of the flammability of plastics - Horizontal and Vertical Methods", place the sample horizontally or vertically, ignite the sample with a specified flame, observe and record the burning behavior of the sample, and evaluate the flame retardant performance level of the sample.

[0078] 3. Anti-mildew performance: According to GB / T 24330-2009 "Test method for anti-mildew performance of plastics", the sample is placed in a culture medium containing specific mold spores and cultured for a certain period of time under certain temperature and humidity conditions. Then, the anti-mildew performance of the sample is rated according to the rating method in the standard by observing the mold growth on the sample surface.

[0079] 4. Tensile strength: According to GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", use an electronic tensile testing machine, clamp the dumbbell-shaped specimen on the fixture of the testing machine, stretch the specimen at a certain speed until it breaks, record the maximum tensile force when the specimen breaks, and calculate the tensile strength based on the original cross-sectional area of ​​the specimen.

[0080] 5. Deep curing: Performed according to the provisions of GB / T 32369-2015 "Determination of curing degree of sealant".

[0081] The performance test results are shown in Table 1 below:

[0082] Table 15 Performance Test Results of Samples

[0083]

[0084]

[0085] The test results above show that the flame-retardant and mildew-resistant silicone rubber prepared in this invention exhibits superior flame retardancy and mildew resistance compared to commercially available Dow Corning SE9184 and Xinwei 388 flame-retardant silicone rubbers. Furthermore, it boasts rapid curing speed and excellent workability. It is also environmentally friendly and has no toxic side effects on the human body. Therefore, the flame-retardant and mildew-resistant silicone rubber prepared in this invention has broad application prospects in many fields such as electronics, fireproofing in buildings, and moisture-proofing.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical methods of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical methods of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical methods to deviate from the spirit and scope of the technical methods of the present invention.

Claims

1. A flame-retardant mildew-proof silicone gum, characterized by comprising: The flame-retardant and mildew-resistant silicone rubber comprises, by weight: 53-62 parts of hydroxyl-terminated polysiloxane, 7-10 parts of fumed silica, 1-3 parts of flame retardant, 5-13 parts of precipitated silica, 2-7 parts of color paste, 2-5 parts of coupling agent, 0.4-1.5 parts of composite titanium compound, 3-8 parts of crosslinking agent, 1-3 parts of toughening agent, 0.1-0.4 parts of mildew inhibitor, and 0.5-2.5 parts of silicone oil.

2. The flame-retardant mildew-proof silicone gel according to claim 1, characterized in that, The hydroxyl-terminated polysiloxane is α,ω-dihydroxypolydimethylsiloxane.

3. The flame-retardant mildew-proof silicone gel according to claim 1, characterized in that, The particle size of the fumed silica is 7 nm to 40 nm.

4. The flame-retardant mildew-proof silicone gel according to claim 1, characterized in that, The color paste is at least one of carbon black, titanium dioxide, iron oxide red, phthalocyanine blue, and phthalocyanine green.

5. The flame-retardant mildew-proof silicone gel according to claim 1, characterized in that, The composite titanium compound is a mixture of tetraisopropyl titanate and bis(acetylacetonyl)diisopropyl titanate; the weight ratio of the tetraisopropyl titanate to the bis(acetylacetonyl)diisopropyl titanate is 1:0.25-1.

6. The flame-retardant mildew-proof silicone gel according to claim 1, characterized in that, The toughening agent is γ-methacryloxypropyltrimethoxysilane-modified hollow glass microspheres.

7. The flame-retardant mildew-proof silicone gel according to claim 1, characterized in that, The flame retardant is at least one of decabromodiphenyl ethane and decabromodiphenyl ether; the mildew inhibitor is at least one of nano silver powder and nano zinc oxide.

8. The flame-retardant mildew-proof silicone gel according to claim 1, characterized in that, The coupling agent is at least one of methyltriethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane; the crosslinking agent is at least one of γ-chloropropyltriethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, and tetraethyl orthosilicate.

9. A process for the preparation of a fire-retardant and mildew-resistant silicone gum according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. By weight, add hydroxyl-terminated polysiloxane, color paste, fumed silica and silicone oil into a planetary mixer and stir for 30 min to 120 min under a vacuum of 0.09 MPa and a rotation speed of 25 rpm to 60 rpm to obtain the first mixture; the fumed silica needs to be dried in an oven at 90℃ to 150℃ for 5 h before being added to the planetary mixer; S2. Add precipitated silica, flame retardant and mildew inhibitor to the first mixture, and stir for 30 min to 120 min under vacuum of 0.09 MPa and rotation speed of 25 rpm to 35 rpm to obtain the second mixture. S3. Prepare a toughening agent, then add the toughening agent, crosslinking agent, composite titanium compound and coupling agent to the second mixture, and stir for 45min to 120min under vacuum of 0.09MPa and rotation speed of 25rpm to 60rpm to obtain the finished product, namely flame-retardant and mildew-proof silicone.

10. The method for preparing a flame-retardant and mildew-resistant silicone rubber according to claim 9, characterized in that, The method for preparing the toughening agent includes the following steps: (1) Dissolve γ-methacryloxypropyltrimethoxysilane in anhydrous ethanol to prepare a coupling agent solution with a mass fraction of 1% to 3%; use anhydrous ethanol as a solvent to dissolve γ-methacryloxypropyltrimethoxysilane to prepare a solution with a mass fraction of 1% to 3%; (2) add clean microbeads to the above solution at a mass ratio of 1:5 to 10, and stir the reaction at 40℃ to 60℃ and 150rpm to 200rpm for 2h to 3h to obtain a condensation reaction solution; (3) The condensation reaction solution was centrifuged and washed 2 to 3 times with anhydrous ethanol, and then vacuum dried at 60℃ to 80℃ for 3 to 4 hours to obtain activated microbeads. (4) Disperse titanium dioxide and zinc oxide nanoparticles in water to prepare a suspension with a solid content of 5% to 8%, then add sodium polyacrylate and disperse at high speed of 3000 rpm to 4000 rpm for 30 min to 40 min to obtain a coating solution; the amount of sodium polyacrylate added is 0.5% to 1% of the total mass of the coating solution. (5) Immerse the activated microspheres in the coating solution, and after 10 min to 15 min, pull them up at a speed of 2 cm / min to 3 cm / min to form a film. Then dry them at 80℃ to 100℃ for 1 h to 2 h and calcine them at 400℃ to 500℃ for 2 h to 3 h to obtain hollow glass microspheres modified with γ-methacryloyloxypropyltrimethoxysilane, i.e. toughening agent.

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