Alkoxy-terminated silicone oil as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of silica gel, and relates to alkoxy-containing end-capped silicone oil and a preparation method and application thereof, and the structure of the alkoxy-containing end-capped silicone oil is shown as a formula (I). The alkoxy-containing end-capped silicone oil provided by the invention overcomes the problems of poor storage stability of traditional silicone oil, viscosity peak appearing in the later silica gel preparation process and the like; the preparation method does not need a solvent, and overcomes the defects of long time consumption, large catalyst dosage, high cost, environmental pollution, complicated operation and the like of the traditional process; the sealant prepared from the alkoxy-terminated silicone oil and the nano zinc oxide subjected to surface modification treatment keeps good flexibility and weather resistance, effectively improves the air tightness of silica gel, plays a better sealing and protecting role on gas in occasions with high performance requirements, and widens the application scene of the sealant. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of silica gel, and in particular relates to an alkoxy-terminated silicone oil and a preparation method and application thereof. Background Art

[0002] Silicone is a synthetic material with excellent high and low temperature resistance, and its temperature resistance range is usually between -60℃ and 250℃. It not only has good elasticity and softness, but also has excellent weather resistance, and can resist the erosion of ultraviolet rays, oxygen, moisture and some chemicals. In addition, silicone also exhibits good electrical insulation, so it is very common in the insulation and packaging of electronic components.

[0003] Silicone's biocompatibility is also a major advantage. It is non-toxic, tasteless, and odorless. It is not easy to cause allergies or other adverse reactions when in contact with human tissue. Therefore, it is often used in medical devices and health products. In addition, silicone tubes have been tested by SGS and meet the standards of RoHs, PAHs and eight heavy metals, ensuring that they are 100% completely non-toxic and tasteless.

[0004] However, the existing silicone oil for preparing silica gel has poor storage stability, and problems such as viscosity peaks occur in the later stage of preparing silica gel; and the process of preparing silicone oil has disadvantages such as long time, large amount of catalyst, high cost, environmental pollution, and cumbersome operation. At the same time, the air tightness of silica gel needs to be further improved to broaden its application scenarios. Summary of the invention

[0005] In view of the deficiencies of the above-mentioned prior art, the present invention provides an alkoxy-terminated silicone oil and a preparation method and application thereof. The specific technical scheme is as follows:

[0006] The first object of the present invention is to provide an alkoxy-terminated silicone oil, the structure of which is shown in formula (I):

[0007]

[0008] Among them, a=1-5, x=0-25, y=240-2600,

[0009] R 1 =CH 2 CH 2 , R 2 = R 3 =CH 3 or Ph (phenyl).

[0010] The alkoxy-terminated silicone oil provided by the present invention overcomes the problems of poor storage stability of traditional silicone oil and viscosity peak in the later preparation process of silica gel; phenyl groups are introduced into the molecular structure and applied to silica gel to effectively improve the air tightness of silica gel.

[0011] The second object of the present invention is to provide a method for preparing the above-mentioned alkoxy-terminated silicone oil, comprising the following steps:

[0012] (1) heating a hydrogen-containing double end cap and vinyl trialkoxysilane under the action of a platinum catalyst, and performing low-pressure distillation to obtain a hydrogen-containing alkoxy end capping agent;

[0013] (2) heating the hydrogen-containing alkoxy-terminated agent obtained in step (1) and the vinyl-terminated polysiloxane under the action of a platinum catalyst to react to obtain an alkoxy-terminated silicone oil.

[0014] The preparation method of the alkoxy-terminated silicone oil of the present invention does not require a solvent, and overcomes the shortcomings of the traditional process such as long time, large amount of catalyst, high cost, environmental pollution, and complicated operation.

[0015] Furthermore, the structure of the hydrogen-containing alkoxy end-capping agent synthesized in step (1) is shown in formula (II):

[0016]

[0017] Where a = 1-5, R 1 =CH 2 CH 2 , R 2 =

[0018] The reaction is as follows:

[0019]

[0020] Furthermore, the structure of the vinyl-terminated polysiloxane is shown in formula (III):

[0021]

[0022] Where x = 0-25, y = 240-2600, R 3 =CH 3 or Ph; R 3 =CH 3 When x=15-25, R 3 =Ph, preferably x=8-12.

[0023] Further, the reaction formula for synthesizing alkoxy-terminated silicone oil is as follows:

[0024]

[0025] Furthermore, in step (1), the molar ratio of the hydrogen-containing double head to the vinyl trialkoxy silane is 1:(1-2); the mass ratio of the total amount of the hydrogen-containing double head and the vinyl trialkoxy silane to the platinum catalyst is 100:(0.1-0.5); in step (2), the molar ratio of the hydrogen-containing alkoxy end-capping agent to the vinyl-terminated polysiloxane is (2-3):1; the mass ratio of the total amount of the hydrogen-containing alkoxy end-capping agent and the vinyl-terminated polysiloxane to the platinum catalyst is 100:(0.1-0.5).

[0026] Furthermore, in step (1), the heating reaction temperature is 80-120°C, and the reaction time is 1-3h; the conditions for low-pressure distillation are a temperature of 80-120°C, a vacuum degree lower than -0.09MPa, and a low-pressure distillation time of 1-3h; in step (2), the heating reaction temperature is 100-120°C, and the reaction time is 1-3h.

[0027] Furthermore, the platinum catalyst is a platinum (0)-divinyltetramethyldisiloxane complex or a platinum (0)-vinylamino complex; and the platinum content of the platinum catalyst is 1000-5000 ppm.

[0028] The third object of the present invention is to provide the use of the above-mentioned alkoxy-terminated silicone oil in the preparation of silica gel.

[0029] Furthermore, the silica gel comprises the following components in parts by weight:

[0030] The composition comprises 60-95 parts of alkoxy-terminated silicone oil, 0-3 parts of carbon black or color paste, 5-35 parts of fumed silica, 1-30 parts of nano zinc oxide, 0.5-5 parts of dehydrating agent, 0.5-5 parts of crosslinking agent, 0.5-5 parts of coupling agent and 0.1-2 parts of catalyst.

[0031] The silica gel is a low-permeability dealcoholized silicone sealant, which introduces phenyl-containing alkoxy-terminated silicone oil into the molecular structure, solves the problem of viscosity peak in the preparation process of silica gel, improves the air tightness of silica gel, plays a better sealing and protective role for gas in high-performance occasions, and maintains good flexibility and weather resistance. The present invention effectively controls the phenyl content, and the phenyl content should not be too large. When the phenyl content reaches a certain amount, the air tightness is not significantly improved, but the toughness and yellowing resistance are affected.

[0032] Furthermore, the nano zinc oxide is surface-modified nano zinc oxide, and the surface modification method of the nano zinc oxide is as follows:

[0033] The liquid surface modifier is sprayed onto the surface of the stirred nano zinc oxide powder three times according to the mass fraction of 1-5% of the nano zinc oxide powder, the rotor linear speed is 80-100 m / s, the temperature is 120-170°C, after stirring for 3-5 hours, the temperature is lowered to below 30-50°C, the powder is discharged and sealed for storage.

[0034] Furthermore, the structure of the liquid surface modifier is shown in structural formula (IV):

[0035]

[0036] Where n = 1-5, m = 2-8, -C m H 2m+1 It has a branched or straight chain structure.

[0037] The addition of nano zinc oxide of the present invention can effectively improve the air tightness of silica gel. By modifying the surface of nano zinc oxide with a liquid surface modifier of the formula (IV), the addition amount of nano zinc oxide can be effectively increased, thereby improving the air tightness of silica gel.

[0038] Furthermore, the fumed silica is one or more of Wacker H18, Cabot TS-610, Deshan DM-20S, and DM-30; the dehydrating agent is vinyltrimethoxysilane or hexamethyldisilazane; the crosslinking agent is tetraalkoxysilane or methyltrialkoxysilane; the coupling agent is a silane coupling agent, preferably an amino coupling agent, preferably one or more of KH550, KH792, A-1170, and AMMO; the catalyst is a tin or titanium catalyst, preferably a titanium catalyst, preferably DuPont's H9000 or Changzhou Kairui Chemical's KRTi-1.

[0039] Furthermore, the preparation method of silica gel comprises the following steps:

[0040] After the alkoxy-terminated silicone oil, carbon black or color paste, fumed silica and nano zinc oxide are stirred and mixed, vacuum is turned on and stirring is continued evenly; after pressure relief, a dehydrating agent, a crosslinking agent, a coupling agent and a catalyst are added, vacuum mixing is performed for 20-40 minutes, and then pressure relief is performed, and the discharged material is sealed and stored.

[0041] The beneficial effects of the present invention are:

[0042] The present invention adopts the method of hydrosilylation to synthesize alkoxy-terminated silicone oil, which overcomes the problems of poor storage stability of traditional silicone oil and viscosity peak in the later preparation process of silica gel; and the preparation method does not require solvent, which overcomes the shortcomings of traditional processes such as long time, large amount of catalyst, high cost, environmental pollution, and complicated operation.

[0043] The alkoxy-terminated silicone oil containing phenyl in the molecular structure synthesized by the present invention and the surface-modified nano zinc oxide can be used to prepare low-permeability dealcoholized silicone sealant, which effectively improves the air tightness of silicone while maintaining good flexibility and weather resistance, and plays a better sealing and protective role for gas in occasions with high performance requirements, thereby broadening its application scenarios. DETAILED DESCRIPTION

[0044] The principles and features of the present invention are described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0045] Preparation of surface modified nano zinc oxide:

[0046] As shown in the structural formula (IV), n=3, -C 4 H 9 3 parts of a linear liquid surface modifier are sprayed three times onto the surface of the stirred nano zinc oxide powder, once every 20 minutes. The nano zinc oxide powder is 100 parts, the rotor linear speed is 100 m / s, the temperature is 150°C, and stirring is continued for 4 hours after all the liquid surface modifier is added. The temperature is lowered to below 40°C, and the surface-modified nano zinc oxide is sealed and stored for later use.

[0047] The surface-modified nano zinc oxide is used in the preparation of the sealant in the examples or comparative examples.

[0048] Embodiment 1:

[0049] 1. Preparation of alkoxy-terminated silicone oil:

[0050] (1) Synthesis a=1,R 2 =-CH 3 , a hydrogen-containing alkoxy end-capping agent of structure (II): a hydrogen-containing double end cap and vinyl trimethoxysilane in a molar ratio of 1:1.5, 100 parts in total, are added into a flask equipped with a stirrer, a reflux condenser and a thermometer, and 0.15 parts of a platinum (0)-divinyltetramethyldisiloxane complex having a platinum content of 5000ppm is added at the same time, stirred and heated to 100°C, reacted for 2h, removed the condensation reflux device, lowered the temperature to 80°C, and carried out low-pressure distillation to obtain a hydrogen-containing alkoxy end-capping agent;

[0051] (2) the hydrogen-containing alkoxy end-capping agent obtained in step (1) and R 3 =-CH 3, x=24, y=1200 vinyl terminated polysiloxane according to the molar ratio of 2.2:1, the total amount is 100 parts, mixed evenly, and 0.15 parts of platinum (0)-divinyltetramethyldisiloxane complex with a platinum content of 5000ppm is added at the same time, the temperature is raised to 120℃, after reacting for 2h, the vacuum is opened, and the low boiling point is removed to obtain a=1, R 2 =-CH 3 , R 3 =-CH 3 , alkoxy-terminated silicone oil A with x=24 and y=1200, sealed and set aside.

[0052] 2. Preparation of low permeability dealcoholized silicone sealant:

[0053] In a reaction kettle, add 90 parts of alkoxy-terminated silicone oil A, 0.5 parts of carbon black, 20 parts of fumed silica Wacker H2000, and 15 parts of surface-modified nano zinc oxide. After stirring and mixing at a speed of 1000 rpm, turn on the vacuum to continue stirring the materials evenly, and the vacuum is less than -0.08 MPa. After nitrogen pressure relief, add 2 parts of dehydrating agent vinyl trimethoxy silane, 2 parts of cross-linking agent methyl trimethoxy silane, 1 part of coupling agent AMMO, and 0.5 parts of transparent titanium catalyst DuPont H2000. Vacuum, vacuum <-0.08 MPa, mix for 30 minutes, fill with nitrogen to relieve pressure, and seal the discharged materials for storage.

[0054] Embodiment 2:

[0055] 1. Preparation of alkoxy-terminated silicone oil:

[0056] Step (1) is the same as in Example 1 and will not be described again here;

[0057] (2) the hydrogen-containing alkoxy end-capping agent obtained in step (1) and R 3 =-Ph, x=12, y=1200 vinyl-terminated polysiloxane in a molar ratio of 2.2:1, a total of 100 parts, mixed evenly, and at the same time added 0.15 parts of platinum (0)-divinyltetramethyldisiloxane complex with a platinum content of 5000ppm, heated to 120°C, reacted for 2h, opened the vacuum, removed the low boiling point, and obtained a=1, R 2 =-CH 3 , R 3 =-Ph, x=12, y=1200, alkoxy-terminated silicone oil B, sealed for standby use.

[0058] 2. Preparation of low permeability dealcoholized silicone sealant:

[0059] In the reaction kettle, add 90 parts of alkoxy-terminated silicone oil B, 0.5 parts of carbon black, 20 parts of fumed silica Wacker H2000, and 15 parts of surface-modified nano zinc oxide. After stirring and mixing at a speed of 1000 rpm, turn on the vacuum to continue stirring the materials evenly, and the vacuum is less than -0.08MPa. After nitrogen pressure relief, add 2 parts of dehydrating agent vinyl trimethoxy silane, 2 parts of cross-linking agent methyl trimethoxy silane, 1 part of coupling agent AMMO, and 0.5 parts of transparent titanium catalyst DuPont H2000. Vacuum, vacuum <-0.08MP, mix for 30 minutes, fill with nitrogen to relieve pressure, and seal the discharged materials for storage.

[0060] Embodiment 3:

[0061] 1. Preparation of alkoxy-terminated silicone oil:

[0062] Step (1) is the same as in Example 1 and will not be described again here;

[0063] (2) the hydrogen-containing alkoxy end-capping agent obtained in step (1) and R 3 =-CH 3 , x = 12, y = 1200 vinyl-terminated polysiloxane according to the molar ratio of 2.2:1, the total amount of 100 parts, mixed evenly, and at the same time added 0.15 parts of platinum (0)-divinyltetramethyldisiloxane complex with a platinum content of 5000ppm, heated to 120 ° C, reacted for 2 hours, opened the vacuum, removed the low boiling point, and obtained a = 1, R 2 =-CH 3 , R 3 =-CH 3 , alkoxy-terminated silicone oil C with x=12, y=1200, sealed and set aside.

[0064] 2. Preparation of low permeability dealcoholized silicone sealant:

[0065] In the reaction kettle, add 90 parts of alkoxy-terminated silicone oil C, 0.5 parts of carbon black, 20 parts of fumed silica Wacker H2000, and 15 parts of surface-modified nano zinc oxide. After stirring and mixing at a speed of 1000 rpm, turn on the vacuum to continue stirring the materials evenly, and the vacuum is less than -0.08MPa. After nitrogen pressure relief, add 2 parts of dehydrating agent vinyl trimethoxy silane, 2 parts of cross-linking agent methyl trimethoxy silane, 1 part of coupling agent AMMO, and 0.5 parts of transparent titanium catalyst DuPont H2000. Vacuum, vacuum <-0.08MP, mix for 30 minutes, fill with nitrogen to relieve pressure, and seal the discharged materials for storage.

[0066] Embodiment 4:

[0067] 1. Preparation of alkoxy-terminated silicone oil:

[0068] The preparation method is the same as that in Example 3 and will not be described again here;

[0069] 2. Preparation of low permeability dealcoholized silicone sealant:

[0070] In the reaction kettle, add 90 parts of alkoxy-terminated silicone oil C, 0.5 parts of carbon black, 20 parts of fumed silica Wacker H2000, and 20 parts of surface-modified nano zinc oxide. After stirring and mixing at a speed of 1000 rpm, turn on the vacuum to continue stirring the materials evenly, and the vacuum is less than -0.08MPa. After nitrogen pressure relief, add 2 parts of dehydrating agent vinyl trimethoxy silane, 2 parts of cross-linking agent methyl trimethoxy silane, 1 part of coupling agent AMMO, and 0.5 parts of transparent titanium catalyst DuPont H2000. Vacuum, vacuum <-0.08MP, mix for 30 minutes, fill with nitrogen to relieve pressure, and seal the discharged materials for storage.

[0071] Embodiment 5:

[0072] 1. Preparation of alkoxy-terminated silicone oil:

[0073] The preparation method is the same as that in Example 1 and will not be described again here;

[0074] 2. Preparation of low permeability dealcoholized silicone sealant:

[0075] In a reaction kettle, add 90 parts of alkoxy-terminated silicone oil A, 0.5 parts of carbon black, 20 parts of fumed silica Wacker H2000, and 20 parts of surface-modified nano zinc oxide. After stirring and mixing at a speed of 1000 rpm, turn on the vacuum to continue stirring the materials evenly, and the vacuum is less than -0.08 MPa. After nitrogen pressure relief, add 2 parts of dehydrating agent vinyl trimethoxy silane, 2 parts of cross-linking agent methyl trimethoxy silane, 1 part of coupling agent AMMO, and 0.5 parts of transparent titanium catalyst DuPont H2000. Vacuum, vacuum <-0.08 MPa, mix for 30 minutes, fill with nitrogen to relieve pressure, and seal the discharged materials for storage.

[0076] Comparative Example 1:

[0077] 1. Preparation of alkoxy-terminated silicone oil:

[0078] Step (1) is the same as in Example 1 and will not be described again here;

[0079] (2) the hydrogen-containing alkoxy end-capping agent obtained in step (1) and R 3 =-CH 3 , x=0, y=2000 vinyl terminated polysiloxane in a molar ratio of 2.2:1, a total of 100 parts, mixed evenly, and at the same time added 0.15 parts of platinum (0)-divinyltetramethyldisiloxane complex with a platinum content of 5000ppm, heated to 120℃, reacted for 2h, opened the vacuum, removed the low boiling point, and obtained a=1, R 2 =-CH 3, R 3 =-CH 3 , alkoxy-terminated silicone oil D with x=0, y=2000, sealed and set aside.

[0080] 2. Preparation of low permeability dealcoholized silicone sealant:

[0081] The difference from Example 1 is that "alkoxy-terminated silicone oil D" is used instead of "alkoxy-terminated silicone oil A", and surface-modified nano zinc oxide is not added.

[0082] Comparative Example 2:

[0083] The difference from Example 1 is that "alkoxy-terminated silicone oil D" is used instead of "alkoxy-terminated silicone oil A", and "nano zinc oxide without surface modification" is used instead of "nano zinc oxide with surface modification".

[0084] Comparative Example 3:

[0085] The difference from Example 1 is that "alkoxy-terminated silicone oil D" is used instead of "alkoxy-terminated silicone oil A", and 20 parts of "surface-modified nano zinc oxide" are used.

[0086] Comparative Example 4:

[0087] The difference from Example 1 is that "surface-modified nano zinc oxide" is not added.

[0088] Comparative Example 5:

[0089] The difference from Example 1 is that "nano zinc oxide without surface modification" is used instead of "nano zinc oxide with surface modification".

[0090] Test Examples

[0091] The properties of the sealants prepared in Examples 1-5 of the present invention and Comparative Examples 1-5 were tested by the following test method. The results are shown in Tables 1 and 2.

[0092] Test 1-Surface drying time test:

[0093] The surface drying time is tested in accordance with GB / T 13477.5-2002 "Test methods for building sealing materials Part 5: Determination of surface drying time".

[0094] Test 2 - Depth of Cure Test:

[0095] Apply glue to the inside of the PTFE plate with a slot (depth greater than 5mm), remove the cured upper layer after 24 hours, and measure the thickness of the cured part.

[0096] Test 3 - Extrusion rate test:

[0097] The test is carried out in accordance with GB / T 13477.4-2002 "Test methods for building sealing materials Part 4: Determination of extrudability of original packaged single-component sealing materials".

[0098] Test 4-Air permeability test:

[0099] The air permeability after curing was tested according to ASTM-D449 "Specification for Asphalt for Moisture and Waterproofing", and the curing conditions were as follows: 25°C, 50% RH, 7 days.

[0100] The test results of Examples 1-5 are shown in Table 1, and the test results of Comparative Examples 1-5 are shown in Table 2.

[0101] Table 1 Performance test results of samples obtained in Examples 1-5

[0102]

[0103]

[0104] Table 2 Performance test results of samples obtained from comparative examples 1-5

[0105] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Surface drying time, min 35 32 33 32 25 24H curing depth, mm ≥5 ≥5 4.7 3.5 2.4 Extrusion rate, g / min 300 100 200 200 20 Water vapor permeability, Perm 12.4 9.6 8.2 5.1 2.4

[0106] The surface drying time of Examples 1-5 and Comparative Examples 1-5 is similar, all within the range of 25-35min, but the 24H curing depth is significantly different, and the curing depth is positively correlated with the air permeability. It can be seen from Comparative Examples 1 and 2, 4 and 5 that the addition of nano zinc oxide can significantly reduce the air permeability of silica gel; it can be seen from Examples 1 and 5, Comparative Examples 2 and 3 that with the increase in the amount of zinc oxide added, the air permeability of silica gel decreases; by comparing the extrusion rates of Example 1 and Comparative Example 5, it can be seen that the surface modification of nano zinc oxide can significantly reduce the viscosity of silica gel and improve the process performance; by comparing Examples 1-3 and Comparative Example 2, combined with Comparative Examples 4-5 and Comparative Example 3, it can be seen that the introduction of phenyl can effectively reduce the air permeability of silica gel; and it can be seen from Examples 1-3 that with the increase of phenyl content, the air permeability of silica gel decreases, and when the phenyl content is the same, the air permeability of silica gel with uniform phenyl distribution is worse than that of silica gel with concentrated phenyl distribution.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An alkoxy-terminated silicone oil, characterized in that: The structure is shown in formula (I): Among them, a=1-5, x=0-25, y=240-2600, R1=CH2CH2, R3=CH3 or Ph.

2. A method for preparing an alkoxy-terminated silicone oil as claimed in claim 1, characterized in that: The steps include: (1) heating a hydrogen-containing double end cap and vinyl trialkoxysilane under the action of a platinum catalyst, and performing low-pressure distillation to obtain a hydrogen-containing alkoxy end capping agent; (2) heating the hydrogen-containing alkoxy-terminated agent obtained in step (1) and the vinyl-terminated polysiloxane under the action of a platinum catalyst to react to obtain an alkoxy-terminated silicone oil.

3. The method for preparing the alkoxy-terminated silicone oil according to claim 2, characterized in that: The structure of the vinyl-terminated polysiloxane is shown in formula (III): Wherein, x=0-25, y=240-2600, R3=-CH3 or -Ph.

4. The method for preparing the alkoxy-terminated silicone oil according to claim 2, characterized in that: In step (1), the molar ratio of the hydrogen-containing double head to the vinyl trialkoxy silane is 1:(1-2); the mass ratio of the total amount of the hydrogen-containing double head and the vinyl trialkoxy silane to the platinum catalyst is 100:(0.1-0.5); in step (2), the molar ratio of the hydrogen-containing alkoxy end-capping agent to the vinyl-terminated polysiloxane is (2-3):1; the mass ratio of the total amount of the hydrogen-containing alkoxy end-capping agent and the vinyl-terminated polysiloxane to the platinum catalyst is 100:(0.1-0.5).

5. The method for preparing the alkoxy-terminated silicone oil according to claim 2, characterized in that: In step (1), the heating reaction temperature is 80-120°C, and the reaction time is 1-3h; the conditions for low-pressure distillation are temperature at 80-120°C, vacuum degree lower than -0.09MPa, and low-pressure distillation time is 1-3h; in step (2), the heating reaction temperature is 100-120°C, and the reaction time is 1-3h.

6. Use of the alkoxy-terminated silicone oil as claimed in claim 1 in the preparation of silica gel.

7. The use according to claim 6, characterized in that: The silica gel comprises the following components in parts by weight: The composition comprises 60-95 parts of alkoxy-terminated silicone oil, 0-3 parts of carbon black or color paste, 5-35 parts of fumed silica, 1-30 parts of nano zinc oxide, 0.5-5 parts of dehydrating agent, 0.5-5 parts of crosslinking agent, 0.5-5 parts of coupling agent and 0.1-2 parts of catalyst.

8. The use according to claim 7, characterized in that: The nano zinc oxide is a surface-modified nano zinc oxide, and the surface modification method of the nano zinc oxide is as follows: The liquid surface modifier is sprayed onto the surface of the stirred nano zinc oxide powder three times according to the mass fraction of 1-5% of the nano zinc oxide powder, the rotor linear speed is 80-100 m / s, the temperature is 120-170°C, after stirring for 3-5 hours, the temperature is lowered to below 30-50°C, the powder is discharged and sealed for storage.

9. The use according to claim 8, characterized in that: The structure of the liquid surface modifier is shown in structural formula (IV): Where n = 1-5, m = 2-8, -C m H 2m+1 It has a branched or straight chain structure.

10. The use according to claim 7, characterized in that: The preparation method of the silica gel comprises the following steps: After the alkoxy-terminated silicone oil, carbon black or color paste, fumed silica and nano zinc oxide are stirred and mixed, vacuum is turned on and stirring is continued evenly; after pressure relief, a dehydrating agent, a crosslinking agent, a coupling agent and a catalyst are added, vacuum mixing is performed for 20-40 minutes, and then pressure relief is performed, and the discharged material is sealed and stored.

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