Tensile high-transmittance silica gel and preparation method thereof

Abstract

The invention relates to the technical field of functional organic silica gel adhesives, in particular to tensile high-transmittance silica gel and a preparation method thereof. The tensile high-transmittance silica gel is prepared from the following raw materials in parts by weight: 70 to 90 parts of 0.08 percent vinyl raw rubber, 10 to 20 parts of 0.22 percent vinyl raw rubber, 2 to 6 parts of vinyl silicone oil, 50 to 60 parts of white carbon black, 2 to 4 parts of hydroxyl silicone oil, 2 to 4 parts of vinyl hydroxyl silicone oil, 2 to 4 parts of hydrogen-containing silicone oil, 10 to 12 parts of functional silane, 1 to 2 parts of platinum catalyst and 0.2 to 0.6 part of zinc stearate. The functional silane contains an epoxy tackifying group and a nitrogen-silicon synergistic flame-retardant block. The tensile high-transmittance silica gel provided by the invention has excellent tear resistance, tensile property and flame retardant property.

Description

Technical Field

[0001] The present application relates to the technical field of functional organic silicone adhesives, and more specifically, to a tensile-resistant and highly transparent silicone and a preparation method thereof. Background Art

[0002] Silicone adhesives are a widely used adhesive, made primarily from polysiloxane and its modified forms, with the addition of certain additives. Silicone adhesives possess unique physical and chemical properties, including excellent heat and cold resistance, weather resistance, corrosion resistance, and low dielectric loss. Consequently, they are widely used in the automotive industry, electronics, aerospace, construction, and other fields.

[0003] Organic silicone adhesives can generally be divided into two categories: addition type and condensation type. Among them, addition type silicone rubber is generally based on linear polysiloxane with vinyl groups and hydrogen-containing siloxane as a cross-linking agent. Under the action of catalysts such as platinum or rhodium, a silylation reaction rapidly occurs at room temperature or high temperature to form a cross-linking structure, thereby achieving an adhesive effect.

[0004] However, with the development of the economy, more and more product processing requires organic silicone materials to have strong tear resistance, tensile strength and high transparency. Even in some electronic product fields, flame retardant requirements are put forward for organic silicone materials. Summary of the Invention

[0005] In order to improve the defects of conventional organic silicone rubber, such as insufficient tear and tensile strength and poor flame retardancy, the present application provides a tensile-resistant and highly transparent silicone rubber and a preparation method thereof.

[0006] In the first aspect, the present application provides a tensile-resistant and highly transparent silicone rubber, which adopts the following technical solution: A tensile-resistant and highly transparent silicone rubber comprises the following raw materials in parts by weight: 70-90 parts of 0.08% vinyl raw rubber, 10-20 parts of 0.22% vinyl raw rubber, 2-6 parts of vinyl silicone oil, 50-60 parts of white carbon black, 2-4 parts of hydroxy silicone oil, 2-4 parts of vinyl hydroxy silicone oil, 2-4 parts of hydrogenated silicone oil, 10-12 parts of functional silane, 1-2 parts of platinum catalyst and 0.2-0.6 parts of zinc stearate, wherein the functional silane contains an epoxy adhesion-promoting group and a nitrogen-silicon synergistic flame-retardant block.

[0007] Preferably, the functional silane is prepared by reacting γ-glycidyloxypropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine, vinyltriethoxysilane and hydrogenated silicone oil.

[0008] The reason why organic silicone has insufficient tear and tensile properties is that its surface is composed of non-polar groups with low reactivity, so its bonding performance with various substrates is poor. After epoxy adhesion-promoting groups are added to organic silicone, organic silicone will obtain extremely good bonding effect, thus having excellent tear and tensile properties.

[0009] This may be due to the high ring tension and active chemical properties of epoxy groups, which react with reactive groups on the substrate surface, such as hydroxyl groups, to form strong chemical bonds, thereby increasing interfacial bonding strength. Epoxy groups also wet the substrate, forming a tight bond through physical adsorption. Epoxy groups can even penetrate into the microscopic pores on the substrate surface, forming a mechanical interlock, resulting in extremely good bonding and excellent tear and tensile properties.

[0010] In addition, when nitrogen-silicon synergistic flame retardant blocks are added to silicone rubber, when the silicone rubber encounters high temperatures, the nitrogen element in the nitrogen-silicon synergistic flame retardant blocks will decompose and release ammonia or nitrogen, thereby diluting oxygen and combustible gases. At the same time, it can also participate in the formation of an expanded carbon layer, thereby isolating heat and oxygen.

[0011] Preferably, the preparation method of the functional silane comprises the following steps: Preparation of epoxy adhesion promoting group silane intermediate: First, γ-glycidyloxypropyltrimethoxysilane and vinyltriethoxysilane are mixed, then toluene solvent and platinum catalyst are added, heated to react, and finally vacuum distilled until there is no low boiling point, thereby obtaining epoxy adhesion promoting group silane intermediate; Preparation of nitrogen-silicon synergistic flame-retardant block intermediate: First, N-[3-(trimethoxysilyl)propyl]ethylenediamine and vinyltriethoxysilane are mixed, then toluene solvent and platinum catalyst are added, heated to react, and finally vacuum distilled until there is no low-boiling point, to obtain a nitrogen-silicon synergistic flame-retardant block intermediate; Preparation of functional silane: First, the epoxy adhesion-promoting group silane intermediate is mixed with the nitrogen-silicon synergistic flame-retardant block intermediate, and then hydrogen-containing silicone oil is added and mixed. Then, a platinum catalyst is added again, heated to react, and finally distilled under reduced pressure to obtain the functional silane.

[0012] Compared with directly adding γ-glycidyloxypropyltrimethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine, the functional silane prepared by reacting γ-glycidyloxypropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine, vinyltriethoxysilane and hydrogen-containing silicone oil will have better compatibility with the organic silane, thereby significantly improving the tear and tensile properties and flame retardant properties of the organic silicone.

[0013] Preferably, in the preparation of the epoxy adhesion promoting group silane intermediate, the reaction is carried out at a temperature of 120-170° C. for 2-6 hours, then the temperature is lowered to 60-100° C., and finally the mixture is distilled under reduced pressure until there is no low boiling point matter; In the preparation of nitrogen-silicon synergistic flame retardant block intermediates, the reaction is carried out at a temperature of 100-160°C for 4-8 hours, then the temperature is lowered to 60-100°C, and finally distilled under reduced pressure until there is no low-boiling matter; In the preparation of functional silane, the reaction is carried out at a temperature of 90-110°C for 3-5 hours, then the temperature is lowered to 60-100°C, and finally distilled under reduced pressure.

[0014] When the epoxy adhesion-promoting group silane intermediate, the nitrogen-silicon synergistic flame-retardant block intermediate and the functional silane are prepared at the above temperature and time, the prepared functional silane will enable the organic silicone to have better tensile and tear resistance and flame retardant properties.

[0015] Preferably, in the preparation of the epoxy adhesion promoting group silane intermediate, the molar ratio of γ-glycidyloxypropyltrimethoxysilane to vinyltriethoxysilane is 1:(1.0-1.2), and the amount of platinum catalyst added is 4-6% of the total mass of the reactants; In the preparation of nitrogen-silicon synergistic flame-retardant block intermediates, the molar ratio of N-[3-(trimethoxysilyl)propyl]ethylenediamine to vinyltriethoxysilane is 1:(1.0-1.2), and the amount of platinum catalyst added is 4-6% of the total mass of the reactants; In the preparation of functional silane, the molar ratio of epoxy adhesion-promoting group silane intermediate, nitrogen-silicon synergistic flame retardant block intermediate and hydrogen-containing silicone oil is 1:1:(2.0-3.0), and the amount of platinum catalyst added is 4-6% of the total mass of the reactants.

[0016] When γ-glycidyloxypropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine, vinyltriethoxysilane and hydrogenated silicone oil are prepared in the above molar ratio, the prepared functional silane will enable the organic silicone to have better tensile and tear resistance and flame retardant properties.

[0017] Preferably, the vinyl silicone oil is a high vinyl content silicone oil.

[0018] Preferably, the white carbon black is 260 specific white carbon black.

[0019] When high vinyl content silicone oil is selected as vinyl silicone oil and 260 specific silica is selected as silica, the functional silane prepared will enable the organic silicone to have better tensile and tear resistance.

[0020] In a second aspect, the present application provides a method for preparing a tensile-resistant and highly transparent silica gel, which adopts the following technical solution: A method for preparing tensile-resistant and highly transparent silica gel comprises the following steps: S1. Check the kneader, heat the inner cylinder with steam to 60-70°C, then add 0.08% vinyl rubber, 0.22% vinyl rubber, 20% of white carbon black, hydrogenated silicone oil, hydroxyl silicone oil, vinyl hydroxyl silicone oil, functional silane, platinum catalyst and zinc stearate in sequence, knead for 5-20 minutes, and then add the remaining white carbon black in batches, knead for 20-80 minutes, stirring at 60-80r / min, until the powder is absorbed, to obtain the pretreated rubber material; S2. Heat the pretreated rubber material to 160-180°C, then keep the temperature constant for 1-2 hours, during which the vacuum degree is controlled at -0.07MPa. After the constant temperature is completed, turn on the cooling water to cool it down, and at the same time reduce the stirring speed to 30-40r / min, cool it for 20-40min, and finally turn off the vacuum discharge. After discharge, cut and cool the rubber material to obtain tensile-resistant and high-transparency silica gel.

[0021] Preferably, in S1, the remaining silica is added in four portions, with each portion being kneaded for 5-20 minutes.

[0022] Preferably, in S1, white carbon black is added in combination with functional silane.

[0023] Adding silica in batches can effectively improve the doping effect of silica, and the combination of silica and functional silane can further improve the compatibility of silica with organic silicone, thereby indirectly improving the tear and tensile properties of organic silicone.

[0024] In summary, this application has the following beneficial effects: 1. The reason why organic silicone has insufficient tear and tensile properties is that its surface is composed of non-polar groups with low reactivity, so its bonding performance with various substrates is poor. However, after adding epoxy tackifying groups to organic silicone, organic silicone will obtain extremely good bonding effect, thus having excellent tear and tensile properties; The reason for this may be that the epoxy group has high ring tension and active chemical properties, which can react with active groups on the substrate surface, such as hydroxyl groups, to form strong chemical bonds, thereby increasing interfacial bonding strength. At the same time, the epoxy group can also wet the substrate, forming a tight bond through physical adsorption. The epoxy group can even penetrate into the microscopic pores on the substrate surface, forming a mechanical interlock, thereby achieving extremely good bonding and excellent tear and tensile properties. In addition, when nitrogen-silicon synergistic flame retardant blocks are added to silicone rubber, when the silicone rubber encounters high temperatures, the nitrogen element in the nitrogen-silicon synergistic flame retardant blocks will decompose and release ammonia or nitrogen, thereby diluting oxygen and combustible gases. At the same time, it can also participate in the formation of an expanded carbon layer, thereby isolating heat and oxygen.

[0025] 2. Compared with directly adding γ-glycidyloxypropyltrimethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine, the functional silane prepared by reacting γ-glycidyloxypropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine, vinyltriethoxysilane and hydrogenated silicone oil will have better compatibility with organic silane, thereby significantly improving the tear and tensile properties and flame retardant properties of organic silicone.

[0026] 3. Adding silica in batches can effectively improve the doping effect of silica, and the combination of silica and functional silane can further improve the compatibility of silica with organic silicone, thereby indirectly improving the tear and tensile properties of organic silicone. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with Examples 1 to 3 and Comparative Examples 1 and 2.

[0028] raw material 0.08% vinyl rubber and 0.22% vinyl rubber were purchased from Shenzhen Huacan Silicone Rubber; vinyl silicone oil with high vinyl content was LNB-1136; white carbon black with a specific ratio of 260 was Huifu HL-260; hydroxy silicone oil was JN-204 from Shandong Juneng; vinyl hydroxy silicone oil was Darl-1; hydrogen-containing silicone oil was Shandong Juneng; platinum catalyst was Shandong Huachen; zinc stearate was Jinan Mingjiang; γ-glycidyloxypropyltrimethoxysilane CAS: 2530-83-8; N-[3-(trimethoxysilyl)propyl]ethylenediamine CAS: 1760-24-3; vinyltriethoxysilane CAS: 78-08-0; toluene CAS: 108-88-3.

[0029] Example 1 A tensile-resistant and highly transparent silicone rubber comprises the following raw materials: 80 g of 0.08% vinyl raw rubber, 16 g of 0.22% vinyl raw rubber, 4 g of vinyl silicone oil, 56 g of white carbon black, 3 g of hydroxy silicone oil, 3 g of vinyl hydroxy silicone oil, 3 g of hydrogenated silicone oil, 11 g of functional silane, 2 g of platinum catalyst, and 0.4 g of zinc stearate.

[0030] A method for preparing tensile-resistant and highly transparent silica gel comprises the following steps: S1. Check the kneader, heat the inner cylinder with steam to 60°C, then add 0.08% vinyl rubber, 0.22% vinyl rubber, white carbon black, hydrogen silicone oil, hydroxy silicone oil, vinyl hydroxy silicone oil, functional silane, platinum catalyst and zinc stearate, and knead for 80 minutes at a stirring speed of 80 r / min until the powder is absorbed to obtain the pretreated rubber material; S2. The pretreated rubber material is heated to 180°C and then kept at a constant temperature for 2 hours. During this period, the vacuum degree is controlled at -0.07MPa. After the constant temperature is completed, the cooling water is turned on to cool down. At the same time, the stirring speed is reduced to 30r / min. Cool for 40 minutes. Finally, the vacuum discharge is turned off. After discharge, the rubber material is cut and cooled to obtain tensile-resistant and highly transparent silica gel.

[0031] The functional silane is prepared by reacting γ-glycidyloxypropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine, vinyltriethoxysilane and hydrogenated silicone oil.

[0032] The preparation method of functional silane comprises the following steps: Preparation of epoxy adhesion-promoting silane intermediate: First, γ-glycidyloxypropyltrimethoxysilane and vinyltriethoxysilane are mixed, and then toluene solvent and platinum catalyst are added. The mixture is reacted at 160°C for 4 hours, then cooled to 80°C, and finally distilled under reduced pressure until there is no low-boiling substance, thereby obtaining the epoxy adhesion-promoting silane intermediate; The molar ratio of γ-glycidyloxypropyltrimethoxysilane to vinyltriethoxysilane is 1:1.2, and the amount of platinum catalyst added is 5% of the total mass of the reactants; Preparation of nitrogen-silicon synergistic flame-retardant block intermediate: First, N-[3-(trimethoxysilyl)propyl]ethylenediamine and vinyltriethoxysilane were mixed, followed by the addition of toluene solvent and platinum catalyst. The mixture was reacted at 130°C for 6 hours, then cooled to 80°C, and finally distilled under reduced pressure until no low-boiling substances were present, thereby obtaining a nitrogen-silicon synergistic flame-retardant block intermediate. The molar ratio of N-[3-(trimethoxysilyl)propyl]ethylenediamine to vinyltriethoxysilane was 1:1.2, and the amount of platinum catalyst added was 5% of the total mass of the reactants; Preparation of functional silane: First, the epoxy adhesion-promoting silane intermediate and the nitrogen-silicon synergistic flame-retardant block intermediate are mixed, followed by the addition of hydrogenated silicone oil and mixing. Platinum catalyst is then added again. The mixture is reacted at 100°C for 4 hours, then cooled to 80°C and finally distilled under reduced pressure to obtain the functional silane. The molar ratio of the epoxy adhesion-promoting silane intermediate, the nitrogen-silicon synergistic flame-retardant block intermediate and the hydrogen-containing silicone oil is 1:1:2.5, and the added amount of the platinum catalyst is 5% of the total mass of the reactants.

[0033] Example 2 The difference from Example 1 is that in S1, white carbon black is added in five times, and each time kneading is 20 minutes. The specific steps are as follows: Check the kneader, heat the inner cylinder with steam to 60°C, then add 0.08% vinyl rubber, 0.22% vinyl rubber, 20% of total white carbon black, hydrogen silicone oil, hydroxy silicone oil, vinyl hydroxy silicone oil, functional silane, platinum catalyst and zinc stearate, and knead for 20 minutes at a stirring speed of 20r / min until the powder is absorbed; Then, the second portion of 20% of the total amount of white carbon black was added to the kneader and kneaded for 20 minutes at a stirring speed of 10 r / min; Then, the third portion of white carbon black (20% of the total amount) was added to the kneader and kneaded for 20 minutes at a stirring speed of 10 r / min. Then, the fourth portion of white carbon black (20% of the total amount) was added to the kneader and kneaded for 20 minutes at a stirring speed of 10 r / min. Finally, the fifth portion of white carbon black (20% of the total amount) was added to the kneader and kneaded for 20 minutes at a stirring speed of 10 r / min to obtain a pretreated rubber compound.

[0034] Example 3 The difference from Example 2 is that in S1, white carbon black and functional silane are added together, and the specific steps are as follows: First, mix the white carbon black with the functional silane, then check the kneader, heat the inner cylinder with steam to 60°C, then add 0.08% vinyl rubber, 0.22% vinyl rubber, 20% of the total amount of white carbon black-functional silane mixture, hydrogenated silicone oil, hydroxyl silicone oil, vinyl hydroxyl silicone oil, platinum catalyst and zinc stearate, knead for 20 minutes at a stirring speed of 20r / min until the powder is absorbed; Then, the second portion of the white carbon black-functional silane mixture (20%) was added to the kneader and kneaded for 20 minutes at a stirring speed of 10 r / min. Then, the third portion of the white carbon black-functional silane mixture (20%) was added to the kneader and kneaded for 20 minutes at a stirring speed of 10 r / min. Then, the fourth portion of the white carbon black-functional silane mixture (20% of the total amount) was added to the kneader and kneaded for 20 minutes at a stirring speed of 10 r / min. Finally, the fifth portion of the silica-functional silane mixture, with a total amount of 20%, was added to the kneader and kneaded for 20 minutes at a stirring speed of 10 r / min to obtain a pretreated rubber compound.

[0035] Comparative Example 1 The difference from Example 1 is that no functional silane is added.

[0036] Comparative Example 2 The difference from Example 1 is that the functional silane is replaced by a mixture of γ-glycidyloxypropyltrimethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine, and the molar ratio of γ-glycidyloxypropyltrimethoxysilane to N-[3-(trimethoxysilyl)propyl]ethylenediamine is 1:1.

[0037] Performance testing 1. Tensile and tear resistance test Three samples were taken from each of Examples 1 to 3 and Comparative Examples 1 and 2, and the glass strength between the adhesive and the aluminum plate was measured using an AI-7000S universal material tensile testing machine in accordance with GB / T 2791-1995. The specific sample preparation procedures are as follows: First, the surface of the aluminum plate was polished with sandpaper and then cleaned with acetone, and then glue was applied. After the gluing was completed, the bonding surfaces of the two substrates were aligned and closed. The bonding thickness was 1mm and the bonding size was 25mm×150mm. After the bonding was completed, the sample was placed flat and dried at 100℃ for 2h.

[0038] The test data are shown in Table 1.

[0039] 2. Flame retardant performance test Three samples were taken from each of Examples 1 to 3 and Comparative Examples 1 and 2, and then the samples were prepared into specimens according to GB / T 10707-2008 and their flame retardant properties were measured. The test data are shown in Table 1.

[0040] Table 1 Test data table of Example 1-Example 3 and Comparative Example 1-Comparative Example 2 With reference to Comparative Example 1 and Comparative Example 2 and in combination with Table 1, it can be seen that compared with Comparative Example 1, the tear strength and flame retardant properties of Comparative Example 2 are significantly improved, which shows that the addition of γ-glycidyloxypropyltrimethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine can effectively improve the tear resistance and flame retardant properties of silicone rubber.

[0041] The reason is that the tear and tensile strength of organic silicone is insufficient because its surface is composed of non-polar groups with low reactivity, so its bonding performance with various substrates is poor. γ-glycidyloxypropyltrimethoxysilane contains a large number of epoxy groups. After epoxy adhesion-enhancing groups are added to organic silicone, the organic silicone will obtain extremely good bonding effect, thus having excellent tear and tensile strength.

[0042] The epoxy group's adhesion-enhancing mechanism lies in its high ring tension and active chemical properties, which allow it to react with reactive groups on the substrate surface, such as hydroxyl groups, to form strong chemical bonds, thereby increasing interfacial bonding strength. Epoxy groups also wet the substrate, forming a tight bond through physical adsorption. Epoxy groups can even penetrate into the microscopic pores on the substrate surface, forming a mechanical interlock, resulting in extremely good bonding and excellent tear and tensile properties.

[0043] In addition, there is a nitrogen-silicon synergistic flame-retardant block in N-[3-(trimethoxysilyl)propyl]ethylenediamine. When the nitrogen-silicon synergistic flame-retardant block is added to the silicone rubber, when the silicone rubber encounters high temperature, the nitrogen element in the nitrogen-silicon synergistic flame-retardant block will decompose and release ammonia or nitrogen, thereby diluting oxygen and combustible gases. At the same time, it can also participate in the formation of an expanded carbon layer, thereby isolating heat and oxygen.

[0044] In summary, when γ-glycidyloxypropyltrimethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine are added to organic silicone, the organic silicone will have extremely excellent tensile and tear resistance and flame retardant properties.

[0045] With reference to Example 1 and Comparative Example 2 and in combination with Table 1, it can be seen that compared with Comparative Example 2, the tear resistance and flame retardant properties of Example 1 are further improved. This shows that, compared with the direct addition of γ-glycidyloxypropyltrimethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine, the functional silane prepared by reacting γ-glycidyloxypropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine, vinyltriethoxysilane and hydrogenated silicone oil will have better compatibility with the organosilane, thereby significantly improving the tear resistance, tensile strength and flame retardant properties of the organic silicone.

[0046] With reference to Examples 1 to 3 and in combination with Table 1, it can be seen that, compared with Example 1, the tensile and tear resistance of Example 2 is significantly improved, and the tensile and tear resistance of Example 3 is further improved. This shows that both the addition of silica in batches and the addition of silica in combination with functional silane can effectively improve the tensile and tear resistance of silicone rubber.

[0047] The reason is that adding silica in batches can effectively improve the doping effect of silica, and the combination of silica and functional silane can further improve the compatibility of silica and organic silicone, thereby indirectly improving the tear and tensile properties of organic silicone.

[0048] In addition, it should be noted that, for Example 3, its performance also includes a hardness of 80 degrees, a tensile strength of about 10 MPa, an elongation of about 400%, and a plasticity of about 260-280.

[0049] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A tensile-resistant and highly transparent silica gel, characterized in that: The invention comprises the following raw materials in parts by weight: 70-90 parts of 0.08% vinyl raw rubber, 10-20 parts of 0.22% vinyl raw rubber, 2-6 parts of vinyl silicone oil, 50-60 parts of white carbon black, 2-4 parts of hydroxy silicone oil, 2-4 parts of vinyl hydroxy silicone oil, 2-4 parts of hydrogen-containing silicone oil, 10-12 parts of functional silane, 1-2 parts of platinum catalyst and 0.2-0.6 parts of zinc stearate, wherein the functional silane contains epoxy adhesion-promoting groups and nitrogen-silicon synergistic flame retardant blocks.

2. The tensile-resistant and highly transparent silica gel according to claim 1, characterized in that: The functional silane is prepared by reacting gamma-glycidyloxypropyltrimethoxysilane, N-[3-(trimethoxysilyl)propyl]ethylenediamine, vinyltriethoxysilane and hydrogen-containing silicone oil.

3. The tensile-resistant and highly transparent silica gel according to claim 2, characterized in that: The preparation method of the functional silane comprises the following steps: Preparation of epoxy adhesion promoting group silane intermediate: First, γ-glycidyloxypropyltrimethoxysilane and vinyltriethoxysilane are mixed, then toluene solvent and platinum catalyst are added, heated to react, and finally vacuum distilled until there is no low boiling point, thereby obtaining epoxy adhesion promoting group silane intermediate; Preparation of nitrogen-silicon synergistic flame-retardant block intermediate: First, N-[3-(trimethoxysilyl)propyl]ethylenediamine and vinyltriethoxysilane are mixed, then toluene solvent and platinum catalyst are added, heated to react, and finally vacuum distilled until there is no low-boiling point, to obtain a nitrogen-silicon synergistic flame-retardant block intermediate; Preparation of functional silane: First, the epoxy adhesion-promoting group silane intermediate is mixed with the nitrogen-silicon synergistic flame-retardant block intermediate, and then hydrogen-containing silicone oil is added and mixed. Then, a platinum catalyst is added again, heated to react, and finally distilled under reduced pressure to obtain the functional silane.

4. The tensile-resistant and highly transparent silica gel according to claim 3, characterized in that: In the preparation of epoxy adhesion promoting group silane intermediate, the reaction is carried out at a temperature of 120-170°C for 2-6 hours, then the temperature is lowered to 60-100°C, and finally the mixture is distilled under reduced pressure until there is no low boiling point. In the preparation of nitrogen-silicon synergistic flame retardant block intermediates, the reaction is carried out at a temperature of 100-160°C for 4-8 hours, then the temperature is lowered to 60-100°C, and finally distilled under reduced pressure until there is no low-boiling matter; In the preparation of functional silane, the reaction is carried out at a temperature of 90-110°C for 3-5 hours, then the temperature is lowered to 60-100°C, and finally distilled under reduced pressure.

5. The tensile-resistant and highly transparent silica gel according to claim 3, characterized in that: In the preparation of epoxy adhesion-promoting silane intermediates, the molar ratio of γ-glycidyloxypropyltrimethoxysilane to vinyltriethoxysilane is 1:(1.0-1.2), and the amount of platinum catalyst added is 4-6% of the total mass of the reactants; In the preparation of nitrogen-silicon synergistic flame-retardant block intermediates, the molar ratio of N-[3-(trimethoxysilyl)propyl]ethylenediamine to vinyltriethoxysilane is 1:(1.0-1.2), and the amount of platinum catalyst added is 4-6% of the total mass of the reactants; In the preparation of functional silane, the molar ratio of epoxy adhesion-promoting group silane intermediate, nitrogen-silicon synergistic flame retardant block intermediate and hydrogen-containing silicone oil is 1:1:(2.0-3.0), and the amount of platinum catalyst added is 4-6% of the total mass of the reactants.

6. The tensile-resistant and highly transparent silica gel according to claim 1, characterized in that: The vinyl silicone oil is selected from high vinyl content silicone oil LNB-1136.

7. The tensile-resistant and highly transparent silica gel according to claim 1, characterized in that: The white carbon black is selected from 260 specific white carbon black.

8. A method for preparing the tensile-resistant and highly transparent silica gel according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Check the kneader, heat the inner cylinder with steam to 60-70°C, then add 0.08% vinyl rubber, 0.22% vinyl rubber, 20% of white carbon black, hydrogen silicone oil, hydroxy silicone oil, vinyl hydroxy silicone oil, functional silane, platinum catalyst and zinc stearate, knead for 5-20 minutes, and then add the remaining white carbon black in batches, knead for 20-80 minutes, stirring at 60-80r / min, until the powder is absorbed, to obtain the pretreated rubber material; S2. Heat the pretreated rubber material to 160-180°C, then keep the temperature constant for 1-2 hours, during which the vacuum degree is controlled at -0.07MPa. After the constant temperature is completed, turn on the cooling water to cool it down, and at the same time reduce the stirring speed to 30-40r / min, cool it for 20-40min, and finally turn off the vacuum discharge. After discharge, cut and cool the rubber material to obtain tensile-resistant and high-transparency silica gel.

9. The method for preparing the tensile-resistant and highly transparent silica gel according to claim 8, characterized in that: In S1, the remaining silica was added in four portions, with kneading for 5-20 minutes each time.

10. The method for preparing tensile-resistant and highly transparent silica gel according to claim 9, characterized in that: In S1, white carbon black is added in combination with functional silane.

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