107 glue-based room-temperature end-capped silicone rubber and preparation method thereof

Abstract

The invention discloses room-temperature end-capped silicone rubber based on 107 glue and a preparation method of the room-temperature end-capped silicone rubber, and relates to the technical field of silicone rubber. The preparation method comprises the following steps: step 1, uniformly mixing 107 glue, isobornyl silane and a catalyst in a nitrogen atmosphere; stirring at room temperature for 1-1.5 hours to obtain room-temperature end-capping base glue; and 2, uniformly stirring and mixing the room-temperature end-capped base rubber, dimethyl silicone oil, the modified filler, methyltrimethoxysilane, gamma-aminopropyltriethoxysilane and an organic tin catalyst in a nitrogen atmosphere, and finally vacuumizing and stirring to obtain the room-temperature end-capped silicone rubber. According to the invention, the prepared room-temperature end-capped silicone rubber has excellent mechanical properties and stability.

Description

Technical Field

[0001] The invention relates to the technical field of silicone rubber, in particular to a room temperature terminated silicone rubber based on 107 rubber and a preparation method thereof. Background Art

[0002] The scientific name of 107 rubber is α, ω-dihydroxypolydimethylsiloxane, which is a room temperature vulcanized silicone rubber. Because it is environmentally friendly and has good electrical properties and chemical stability, it is widely used in electronic instruments, automobiles, construction and other fields.

[0003] In the prior art, the room temperature end-capped silicone rubber based on 107 glue has the following problems: On the one hand, room temperature end-capped silicone rubber has catalysis and storage difficulties; gelation occurs during the catalysis process, affecting the stability and processability of the overall silicone rubber. On the other hand, due to its room temperature cross-linking property, it has poor storage stability. When encountering moisture during storage, the silicone rubber will turn yellow after vulcanization, and the stability will decrease and the viscosity will increase, thus affecting the final performance of the application. In addition, inorganic fillers such as calcium powder are generally introduced into the silicone rubber material to fill the cross-linked network to improve the mechanical properties and applicability of the silicone rubber. However, the compatibility and dispersibility problems of inorganic fillers require improvement in processability and related properties.

[0004] In summary, it is of great significance to solve the above problems and prepare a room temperature terminated silicone rubber based on 107 glue. Summary of the invention

[0005] The object of the present invention is to provide a room temperature terminated silicone rubber based on 107 rubber and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A method for preparing room temperature end-capped silicone rubber based on 107 rubber comprises the following steps:

[0008] Step 1: Under a nitrogen atmosphere, mix 107 glue, isobornylsilane and catalyst evenly; stir at room temperature for 1 to 1.5 hours to obtain a room temperature end-capped base glue;

[0009] Step 2: Under a nitrogen atmosphere, the room temperature end-capped base rubber, dimethyl silicone oil, modified filler, methyltrimethoxysilane, γ-aminopropyltriethoxysilane, and organic tin catalyst are stirred and mixed evenly, and finally vacuumed and stirred to obtain room temperature end-capped silicone rubber.

[0010] More optimally, the raw materials of the room temperature terminated base glue include the following components: by weight, 100 parts of 107 glue, 1 to 3 parts of isobornyl silane, and 0.05 to 0.1 parts of catalyst.

[0011] More optimally, the preparation method of the catalyst is: uniformly disperse hydrophilic fumed silica in deionized water, add phosphoric acid; stir for 1 to 2 hours; heat to 80 to 85°C, drop n-hexanol, and stir to react for 2 to 3 hours; drop a saturated aqueous solution of 3-aminophenylboric acid, continue to react for 2 to 3 hours, evaporate the solvent, and obtain a catalyst; wherein the mass ratio of hydrophilic fumed silica, phosphoric acid, n-hexanol, and 3-aminophenylboric acid is 5:(5 to 5.2):(6 to 6.5):(6 to 6.5).

[0012] In the scheme, the catalyst is improved based on the existing technology CN202210430300.8; the introduction of hydrophilic fumed silica as the base of the catalyst can further inhibit the gelation phenomenon in the capping process, and cooperate with the capping agent to improve the stability of the room temperature capped base glue; at the same time, the mechanical properties of the room temperature capped base glue can be improved.

[0013] More optimally, the 107 glue includes 107 glue A with a pressure of 20,000 mPa·s and 107 glue B with a pressure of 80,000 mPa·s in a mass ratio of 3:2.

[0014] More optimally, the isobornylsilane is prepared by the following method:

[0015] 1-thioglycerol, isobornyl acrylate and azobisisobutyronitrile are added to tetrahydrofuran in sequence and stirred evenly, stirred at room temperature for 2 to 3 hours under ultraviolet light, precipitated with methanol, washed and dried to obtain isobornyl glycerol;

[0016] Add isobornyl glycerol and 3-vinylbenzene boronic acid to tetrahydrofuran, add magnesium sulfate, set the temperature to 25-35° C., stir for 1-1.5 days; filter, evaporate the solvent, wash, and dry to obtain isobornyl borate;

[0017] Add isobornyl borate, mercaptopropyltrimethoxysilane and azobisisobutyronitrile to tetrahydrofuran in sequence and stir evenly. Stir at room temperature for 2 to 3 hours under ultraviolet light, precipitate with methanol, wash and dry to obtain isobornyl silane.

[0018] More optimally, the raw materials of the isobornyl glycerol include the following components by weight: 2 to 2.2 parts of 1-thioglycerol, 4 to 4.5 parts of isobornyl acrylate, 0.002 to 0.005 parts of azobisisobutyronitrile, and 20 to 30 parts of tetrahydrofuran;

[0019] The raw materials of the isobornyl borate ester include the following components by weight: 3 to 3.5 parts of isobornyl glycerol, 1.4 to 1.5 parts of 3-vinylbenzene boronic acid, 80 to 100 parts of tetrahydrofuran, and 2 to 3 parts of magnesium sulfate;

[0020] The raw materials of the isobornyl silane include the following components by weight: 4.5 to 5 parts of isobornyl borate, 2.5 to 3.5 parts of mercaptopropyltrimethoxysilane, 0.002 to 0.005 parts of azobisisobutyronitrile, and 40 to 50 parts of tetrahydrofuran.

[0021] More optimally, the raw materials of the room temperature terminated silicone rubber include the following components: by weight, 100 parts of room temperature terminated base rubber, 12 to 15 parts of dimethyl silicone oil, 12 to 15 parts of modified filler, 8 to 10 parts of methyltrimethoxysilane, 2 to 4 parts of γ-aminopropyltriethoxysilane, and 0.5 to 1 part of organic tin catalyst.

[0022] Preferably, the modified filler is prepared by the following method:

[0023] Add mercaptopropyltrimethoxysilane to a 70-80 wt% ethanol aqueous solution, adjust the pH to 3.5±0.5 with glacial acetic acid, and stir for 20-30 minutes; add hydrophilic fumed silica, heat to 65-70° C., stir for 3-4 hours, wash, and dry to obtain mercapto silica;

[0024] Mercaptosilicon dioxide, azobisisobutyronitrile, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, isobornyl borate and allyltrimethoxysilane are sequentially added into dimethylformamide; the mixture is stirred at 70-75° C. for 3-5 hours, washed and dried to obtain a modified filler.

[0025] More optimally, in the raw material of the mercaptosilica, the mass ratio of mercaptopropyltrimethoxysilane to hydrophilic fumed silica is 2 to 5:100;

[0026] The raw materials of the modified filler include the following components in parts by mass: 50 parts of mercaptosilicon dioxide, 0.1-0.2 parts of azobisisobutyronitrile, 2-3 parts of 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 0.5-1 parts of isobornyl borate, and 2-3 parts of allyltrimethoxysilane.

[0027] More optimally, a room temperature terminated silicone rubber is prepared by a preparation method of room temperature terminated silicone rubber based on 107 glue.

[0028] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: based on 107 glue, isobornyl silane is used as a capping agent to effectively improve the thermal stability and processing performance of the room temperature capped base glue; then it is used as the main component to compound dimethyl silicone oil, organic tin catalyst, and modified filler to obtain room temperature capped silicone rubber; the formula and components are comprehensively optimized to make the room temperature capped silicone rubber have excellent mechanical properties and stability.

[0029] Among them, two viscosities of 107 glue are introduced as the basis through optimization; compared with the use of a single high-viscosity 107 glue; the introduction of a lower viscosity 107 glue compound is helpful to improve the activity of room-temperature terminated silicone rubber; and by optimizing the ratio of 107 glues with different viscosities, the processing performance is improved, and the cross-linking density and mechanical properties of silicone rubber are effectively improved; among them, the low-viscosity 107 glue A is introduced more, because: the capping agent is a larger molecular isobornyl silane; in order to ensure processability, its introduction amount is more than that of the high-viscosity 107 glue B; both effectively control the molecular weight distribution and optimize the rheological properties.

[0030] Among them, isobornyl silane is first reacted with the thiol and olefin groups of 1-thioglycerol and isobornyl acrylate to obtain isobornyl glycerol; then the two alcohol groups contained in it are reacted with the boronic acid group of 3-vinylphenylboronic acid to obtain isobornyl borate; since there is a vinyl group on 3-vinylphenylboronic acid, mercaptopropyltrimethoxysilane is grafted by click reaction to obtain trimethoxysilane containing isobornyl and boron groups; compared with the common vinyltrimethoxysilane, using it as a capping agent can better reduce the gelation tendency, effectively improve the heat stability and hydrolysis resistance; improve storage stability, reduce the change of viscosity during storage, and effectively promote the aging resistance and mechanical properties of room temperature capped silicone rubber.

[0031] Among them, hydrophilic fumed silica is introduced as a reinforcing agent in the room temperature end-capped silicone rubber to inhibit its aggregation, improve its dispersion uniformity, and promote the stability of the room temperature end-capped silicone rubber. It is modified in the scheme. During the modification process: first, it is modified once with mercaptopropyl trimethoxysilane; then, it is modified twice by using mercapto and alkenyl click reactions, grafting copolymerization of 1,3-divinyl-1,1,3,3-tetramethyldisilazane, isobornyl borate, and allyl trimethoxysilane. Among them, compared with the modification using only mercaptopropyl trimethoxysilane, the interface effect is better after two modifications. At the same time, the 1,3-divinyl-1,1,3,3-tetramethyldisilazane introduced after the secondary modification contains NH-groups that can capture free alcohol, thereby effectively improving storage stability; the introduced isobornyl borate has similar compatibility with the base rubber, which can promote its dispersion in room temperature end-capped silicone rubber; and the introduced allyl trimethoxysilane can improve the deep curing performance and increase the reaction compatibility. In this way, the comprehensive performance of room temperature end-capped silicone rubber is effectively improved through two modifications. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0033] It should be noted that the purchasers of all raw materials involved in the present invention are not subject to any special restrictions. Examples include: In the following examples, the specific surface area of ​​the hydrophilic fumed silica is 150 m 2 / g, model is HP150, and the manufacturer is Jiangxi Hongbai New Materials Co., Ltd.; α, ω-dihydroxypolydimethylsiloxane, specifications are 20000mPa·s (107 glue A) and 80000mPa·s (107 glue B); the viscosity of dimethyl silicone oil is 350mPa·s; the above and other raw materials are commercially purchased; in addition, the following parts are by mass.

[0034] Preparation of the catalyst: Disperse 5 parts of hydrophilic fumed silica uniformly in 100 parts of deionized water, add 5.2 parts of phosphoric acid; stir for 2 hours; heat to 80°C, drop 6 parts of n-hexanol, stir and react for 2 hours; drop 3-aminophenylboric acid saturated aqueous solution (6.1 parts of 3-aminophenylboric acid), continue to react for 2 hours, evaporate the solvent to obtain the catalyst.

[0035] Embodiment 1: A method for preparing room temperature end-capped silicone rubber based on 107 rubber, comprising the following steps:

[0036] Pre-preparation: (1) Add 2 parts of 1-thioglycerol, 4.2 parts of isobornyl acrylate, and 0.003 parts of azobisisobutyronitrile to 25 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl glycerol; add 3.2 parts of isobornyl glycerol and 1.43 parts of 3-vinylphenylboronic acid to 100 parts of tetrahydrofuran, add 2.8 parts of magnesium sulfate, set the temperature to 35°C, and stir for 1 day; filter, evaporate the solvent, wash, and dry to obtain isobornyl borate; add 4.5 parts of isobornyl borate, 3 parts of mercaptopropyltrimethoxysilane, and 0.004 parts of azobisisobutyronitrile to 50 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl silane;

[0037] (2) Add 5 parts of mercaptopropyltrimethoxysilane to a 75wt% ethanol aqueous solution, adjust the pH to 3.6 with glacial acetic acid, and stir for 30 minutes; add 100 parts of hydrophilic fumed silica, heat to 68°C and stir for 3 hours, wash and dry to obtain mercaptosilica; add 50 parts of mercaptosilica, 0.12 parts of azobisisobutyronitrile, 2.5 parts of 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 0.8 parts of isobornyl borate, and 3 parts of allyltrimethoxysilane to dimethylformamide in sequence; stir at 70°C for 4 hours, wash and dry to obtain a modified filler;

[0038] Step 1: Under a nitrogen atmosphere, 100 parts of 107 glue (107 glue A and 107 glue B with a mass ratio of 3:2), 2.2 parts of isobornyl silane, and 0.08 parts of a catalyst were mixed evenly; stirred at room temperature for 1 hour to obtain a room temperature end-capped base glue;

[0039] Step 2: Under a nitrogen atmosphere, 100 parts of room temperature end-capped base rubber, 14 parts of dimethyl silicone oil, 14 parts of modified filler, 8 parts of methyltrimethoxysilane, 3 parts of γ-aminopropyltriethoxysilane, and 0.8 parts of dibutyltin dilaurate were stirred and mixed evenly, and finally vacuumed and stirred to obtain room temperature end-capped silicone rubber.

[0040] Embodiment 2: A method for preparing room temperature end-capped silicone rubber based on 107 rubber, comprising the following steps:

[0041] Pre-preparation: (1) Add 2 parts of 1-thioglycerol, 4.2 parts of isobornyl acrylate, and 0.003 parts of azobisisobutyronitrile to 25 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl glycerol; add 3.2 parts of isobornyl glycerol and 1.43 parts of 3-vinylphenylboronic acid to 100 parts of tetrahydrofuran, add 2.8 parts of magnesium sulfate, set the temperature to 35°C, and stir for 1 day; filter, evaporate the solvent, wash, and dry to obtain isobornyl borate; add 4.5 parts of isobornyl borate, 3 parts of mercaptopropyltrimethoxysilane, and 0.004 parts of azobisisobutyronitrile to 50 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl silane;

[0042] (2) Add 5 parts of mercaptopropyltrimethoxysilane to a 75wt% ethanol aqueous solution, adjust the pH to 3.6 with glacial acetic acid, and stir for 30 minutes; add 100 parts of hydrophilic fumed silica, heat to 68°C and stir for 3 hours, wash and dry to obtain mercaptosilica; add 50 parts of mercaptosilica, 0.12 parts of azobisisobutyronitrile, 2.5 parts of 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 0.8 parts of isobornyl borate, and 3 parts of allyltrimethoxysilane to dimethylformamide in sequence; stir at 70°C for 4 hours, wash and dry to obtain a modified filler;

[0043] Step 1: Under a nitrogen atmosphere, 100 parts of 107 glue (107 glue A and 107 glue B with a mass ratio of 3:2), 1 part of isobornyl silane, and 0.1 part of a catalyst were mixed evenly; stirred at room temperature for 1 hour to obtain a room temperature end-capped base glue;

[0044] Step 2: Under a nitrogen atmosphere, 100 parts of room temperature end-capped base rubber, 15 parts of dimethyl silicone oil, 15 parts of modified filler, 10 parts of methyltrimethoxysilane, 3 parts of γ-aminopropyltriethoxysilane, and 1 part of dibutyltin bis(acetylacetonate) were stirred and mixed evenly, and finally vacuumed and stirred to obtain room temperature end-capped silicone rubber.

[0045] Embodiment 3: A method for preparing room temperature end-capped silicone rubber based on 107 rubber, comprising the following steps:

[0046] Pre-preparation: (1) Add 2 parts of 1-thioglycerol, 4.2 parts of isobornyl acrylate, and 0.003 parts of azobisisobutyronitrile to 25 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl glycerol; add 3.2 parts of isobornyl glycerol and 1.43 parts of 3-vinylphenylboronic acid to 100 parts of tetrahydrofuran, add 2.8 parts of magnesium sulfate, set the temperature to 35°C, and stir for 1 day; filter, evaporate the solvent, wash, and dry to obtain isobornyl borate; add 4.5 parts of isobornyl borate, 3 parts of mercaptopropyltrimethoxysilane, and 0.004 parts of azobisisobutyronitrile to 50 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl silane;

[0047] (2) Add 5 parts of mercaptopropyltrimethoxysilane to a 75wt% ethanol aqueous solution, adjust the pH to 3.6 with glacial acetic acid, and stir for 30 minutes; add 100 parts of hydrophilic fumed silica, heat to 68°C and stir for 3 hours, wash and dry to obtain mercaptosilica; add 50 parts of mercaptosilica, 0.12 parts of azobisisobutyronitrile, 2.5 parts of 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 0.8 parts of isobornyl borate, and 3 parts of allyltrimethoxysilane to dimethylformamide in sequence; stir at 70°C for 4 hours, wash and dry to obtain a modified filler;

[0048] Step 1: Under a nitrogen atmosphere, 100 parts of 107 glue (107 glue A and 107 glue B with a mass ratio of 3:2), 3 parts of isobornyl silane, and 0.1 parts of a catalyst were mixed evenly; stirred at room temperature for 1 hour to obtain a room temperature end-capped base glue;

[0049] Step 2: Under a nitrogen atmosphere, 100 parts of room temperature end-capped base rubber, 12 parts of dimethyl silicone oil, 12 parts of modified filler, 8 parts of methyltrimethoxysilane, 3 parts of γ-aminopropyltriethoxysilane, and 0.8 parts of dibutyltin bis(acetylacetonate) were stirred and mixed evenly, and finally vacuumed and stirred to obtain room temperature end-capped silicone rubber.

[0050] Comparative Example 1: Referring to Example 1, the ratio of 107 glue was adjusted to: 107 glue A and 107 glue B with a mass ratio of 2:3; the rest was the same as Example 1;

[0051] Pre-preparation: (1) Add 2 parts of 1-thioglycerol, 4.2 parts of isobornyl acrylate, and 0.003 parts of azobisisobutyronitrile to 25 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl glycerol; add 3.2 parts of isobornyl glycerol and 1.43 parts of 3-vinylphenylboronic acid to 100 parts of tetrahydrofuran, add 2.8 parts of magnesium sulfate, set the temperature to 35°C, and stir for 1 day; filter, evaporate the solvent, wash, and dry to obtain isobornyl borate; add 4.5 parts of isobornyl borate, 3 parts of mercaptopropyltrimethoxysilane, and 0.004 parts of azobisisobutyronitrile to 50 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl silane;

[0052] (2) Add 5 parts of mercaptopropyltrimethoxysilane to a 75wt% ethanol aqueous solution, adjust the pH to 3.6 with glacial acetic acid, and stir for 30 minutes; add 100 parts of hydrophilic fumed silica, heat to 68°C and stir for 3 hours, wash and dry to obtain mercaptosilica; add 50 parts of mercaptosilica, 0.12 parts of azobisisobutyronitrile, 2.5 parts of 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 0.8 parts of isobornyl borate, and 3 parts of allyltrimethoxysilane to dimethylformamide in sequence; stir at 70°C for 4 hours, wash and dry to obtain a modified filler;

[0053] Step 1: Under nitrogen atmosphere, 100 parts of 107 glue (107 glue A and 107 glue B with a mass ratio of 2:3), 2.2 parts of isobornyl silane, and 0.08 parts of catalyst were mixed evenly; stirred at room temperature for 1 hour to obtain room temperature end-capped base glue;

[0054] Step 2: Under a nitrogen atmosphere, 100 parts of room temperature end-capped base rubber, 14 parts of dimethyl silicone oil, 14 parts of modified filler, 8 parts of methyltrimethoxysilane, 3 parts of γ-aminopropyltriethoxysilane, and 0.8 parts of dibutyltin dilaurate were stirred and mixed evenly, and finally vacuumed and stirred to obtain room temperature end-capped silicone rubber.

[0055] Comparative Example 2: Referring to Example 1, isobornylsilane was replaced with vinyltrimethoxysilane; the rest was the same as Example 1;

[0056] Pre-preparation: add 5 parts of mercaptopropyltrimethoxysilane to a 75wt% ethanol aqueous solution, adjust the pH to 3.6 with glacial acetic acid, and stir for 30 minutes; add 100 parts of hydrophilic fumed silica, heat to 68°C and stir for 3 hours, wash and dry to obtain mercaptosilica; add 50 parts of mercaptosilica, 0.12 parts of azobisisobutyronitrile, 2.5 parts of 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 0.8 parts of isobornyl borate, and 3 parts of allyltrimethoxysilane to dimethylformamide in sequence; stir at 70°C for 4 hours, wash and dry to obtain a modified filler;

[0057] Step 1: Under a nitrogen atmosphere, 100 parts of 107 glue (107 glue A and 107 glue B with a mass ratio of 3:2), 2.2 parts of vinyl trimethoxy silane, and 0.08 parts of a catalyst were mixed evenly; stirred at room temperature for 1 hour to obtain a room temperature end-capped base glue;

[0058] Step 2: Under a nitrogen atmosphere, 100 parts of room temperature end-capped base rubber, 14 parts of dimethyl silicone oil, 14 parts of modified filler, 8 parts of methyltrimethoxysilane, 3 parts of γ-aminopropyltriethoxysilane, and 0.8 parts of dibutyltin dilaurate were stirred and mixed evenly, and finally vacuumed and stirred to obtain room temperature end-capped silicone rubber.

[0059] Comparative Example 3: Referring to Example 1, hydrophilic fumed silica was directly introduced; the rest was the same as Example 1;

[0060] Pre-preparation: 2 parts of 1-thioglycerol, 4.2 parts of isobornyl acrylate, and 0.003 parts of azobisisobutyronitrile are added to 25 parts of tetrahydrofuran in sequence, stirred evenly, stirred at room temperature for 2 hours under ultraviolet light, precipitated with methanol, washed, and dried to obtain isobornyl glycerol; 3.2 parts of isobornyl glycerol and 1.43 parts of 3-vinylphenylboronic acid are added to 100 parts of tetrahydrofuran, 2.8 parts of magnesium sulfate are added, the temperature is set to 35°C, and stirred for 1 day; filtered, the solvent is evaporated, washed, and dried to obtain isobornyl borate; 4.5 parts of isobornyl borate, 3 parts of mercaptopropyltrimethoxysilane, and 0.004 parts of azobisisobutyronitrile are added to 50 parts of tetrahydrofuran in sequence, stirred evenly, stirred at room temperature for 2 hours under ultraviolet light, precipitated with methanol, washed, and dried to obtain isobornyl silane;

[0061] Step 1: Under a nitrogen atmosphere, 100 parts of 107 glue (107 glue A and 107 glue B with a mass ratio of 3:2), 2.2 parts of isobornyl silane, and 0.08 parts of a catalyst were mixed evenly; stirred at room temperature for 1 hour to obtain a room temperature end-capped base glue;

[0062] Step 2: Under a nitrogen atmosphere, 100 parts of room temperature end-capped base rubber, 14 parts of dimethyl silicone oil, 14 parts of hydrophilic fumed silica, 8 parts of methyltrimethoxysilane, 3 parts of γ-aminopropyltriethoxysilane, and 0.8 parts of dibutyltin dilaurate were stirred and mixed evenly, and finally vacuumed and stirred to obtain room temperature end-capped silicone rubber.

[0063] Comparative Example 4: Referring to Example 1, mercapto silicon dioxide was directly introduced; the rest was the same as Example 1;

[0064] Pre-preparation: (1) Add 2 parts of 1-thioglycerol, 4.2 parts of isobornyl acrylate, and 0.003 parts of azobisisobutyronitrile to 25 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl glycerol; add 3.2 parts of isobornyl glycerol and 1.43 parts of 3-vinylphenylboronic acid to 100 parts of tetrahydrofuran, add 2.8 parts of magnesium sulfate, set the temperature to 35°C, and stir for 1 day; filter, evaporate the solvent, wash, and dry to obtain isobornyl borate; add 4.5 parts of isobornyl borate, 3 parts of mercaptopropyltrimethoxysilane, and 0.004 parts of azobisisobutyronitrile to 50 parts of tetrahydrofuran in sequence, stir evenly, stir at room temperature for 2 hours under ultraviolet light, precipitate with methanol, wash, and dry to obtain isobornyl silane;

[0065] (2) adding 5 parts of mercaptopropyltrimethoxysilane to a 75 wt % ethanol aqueous solution, adjusting the pH to 3.6 with glacial acetic acid, and stirring for 30 minutes; adding 100 parts of hydrophilic fumed silica, heating to 68° C. and stirring for 3 hours, washing, and drying to obtain mercapto silica;

[0066] Step 1: Under a nitrogen atmosphere, 100 parts of 107 glue (107 glue A and 107 glue B with a mass ratio of 3:2), 2.2 parts of isobornyl silane, and 0.08 parts of a catalyst were mixed evenly; stirred at room temperature for 1 hour to obtain a room temperature end-capped base glue;

[0067] Step 2: Under a nitrogen atmosphere, 100 parts of room temperature end-capped base rubber, 14 parts of dimethyl silicone oil, 14 parts of mercaptosilicone, 8 parts of methyltrimethoxysilane, 3 parts of γ-aminopropyltriethoxysilane, and 0.8 parts of dibutyltin dilaurate were stirred and mixed evenly, and finally vacuumed and stirred to obtain room temperature end-capped silicone rubber.

[0068] Performance test: The room temperature end-capped silicone rubber prepared in the embodiment and the comparative example was subjected to relevant performance tests, wherein the extrudability of the room temperature end-capped silicone rubber was determined with reference to Part 4 of GB / T13477.4; the tensile strength of the room temperature end-capped silicone rubber was tested with reference to GB / T528, which was recorded as tensile strength A; the encapsulated silicone rubber was placed in a 70°C oven for 7 days, and the tensile strength was measured again, which was recorded as tensile strength B; the obtained data are shown in the following table:

[0069]

[0070]

[0071] Conclusion: From the data in the above table, it can be seen that the present application has prepared a room temperature end-capped silicone rubber with excellent tensile strength and stability. From the comparison data, it can be seen that in Comparative Example 1, due to the change in the ratio of 107 glue A and 107 glue B, the fluidity and processing performance are reduced. In Comparative Example 2, since vinyltrimethoxysilane is replaced with isobornylsilane, the end-capping molecular weight is reduced, which improves the extrusion performance; but the heat resistance stability and mechanical properties are reduced. In Comparative Example 3, due to the direct introduction of hydrophilic gas-phase silica, the compatibility and dispersibility are reduced; and there is no group that can adsorb free alcohol, so the relevant performance is reduced; in Comparative Example 4, since the mercapto silica is only modified once, compared with Example 1, the interfacial effect of the base glue is reduced, and similarly no relevant groups are introduced on the surface, so the relevant performance is reduced.

[0072] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing room temperature end-capped silicone rubber based on 107 rubber, characterized in that: The following steps are involved: Step 1: Under a nitrogen atmosphere, mix 107 glue, isobornylsilane and catalyst evenly; stir at room temperature for 1 to 1.5 hours to obtain a room temperature end-capped base glue; Step 2: Under a nitrogen atmosphere, the room temperature end-capped base rubber, dimethyl silicone oil, modified filler, methyltrimethoxysilane, γ-aminopropyltriethoxysilane, and organic tin catalyst are stirred and mixed evenly, and finally vacuumed and stirred to obtain room temperature end-capped silicone rubber.

2. The method for preparing a room temperature end-capped silicone rubber based on 107 glue according to claim 1, characterized in that: The raw materials of the room temperature end-capped base glue include the following components: by weight, 100 parts of 107 glue, 1 to 3 parts of isobornyl silane, and 0.05 to 0.1 parts of a catalyst.

3. The method for preparing a room temperature end-capped silicone rubber based on 107 glue according to claim 1, characterized in that: The 107 glue includes 107 glue A with a pressure of 20,000 mPa·s and 107 glue B with a pressure of 80,000 mPa·s in a mass ratio of 3:

2.

4. The method for preparing a room temperature end-capped silicone rubber based on 107 glue according to claim 1, characterized in that: The isobornylsilane is prepared by the following method: 1-thioglycerol, isobornyl acrylate and azobisisobutyronitrile are added to tetrahydrofuran in sequence and stirred evenly, stirred at room temperature for 2 to 3 hours under ultraviolet light, precipitated with methanol, washed and dried to obtain isobornyl glycerol; Add isobornyl glycerol and 3-vinylbenzene boronic acid to tetrahydrofuran, add magnesium sulfate, set the temperature to 25-35° C., stir for 1-1.5 days; filter, evaporate the solvent, wash, and dry to obtain isobornyl borate; Add isobornyl borate, mercaptopropyltrimethoxysilane and azobisisobutyronitrile to tetrahydrofuran in sequence and stir evenly. Stir at room temperature for 2 to 3 hours under ultraviolet light, precipitate with methanol, wash and dry to obtain isobornyl silane.

5. The method for preparing a room temperature end-capped silicone rubber based on 107 glue according to claim 4, characterized in that: The raw materials of the isobornyl glycerol include the following components by weight: 2 to 2.2 parts of 1-thioglycerol, 4 to 4.5 parts of isobornyl acrylate, 0.002 to 0.005 parts of azobisisobutyronitrile, and 20 to 30 parts of tetrahydrofuran; The raw materials of the isobornyl borate ester include the following components by weight: 3 to 3.5 parts of isobornyl glycerol, 1.4 to 1.5 parts of 3-vinylbenzene boronic acid, 80 to 100 parts of tetrahydrofuran, and 2 to 3 parts of magnesium sulfate; The raw materials of the isobornyl silane include the following components by weight: 4.5 to 5 parts of isobornyl borate, 2.5 to 3.5 parts of mercaptopropyltrimethoxysilane, 0.002 to 0.005 parts of azobisisobutyronitrile, and 40 to 50 parts of tetrahydrofuran.

6. The method for preparing a room temperature end-capped silicone rubber based on 107 glue according to claim 1, characterized in that: The raw materials of the room temperature terminated silicone rubber include the following components: by weight, 100 parts of room temperature terminated base rubber, 12 to 15 parts of dimethyl silicone oil, 12 to 15 parts of modified filler, 8 to 10 parts of methyltrimethoxysilane, 2 to 4 parts of γ-aminopropyltriethoxysilane, and 0.5 to 1 part of organic tin catalyst.

7. The method for preparing a room temperature end-capped silicone rubber based on 107 glue according to claim 1, characterized in that: The modified filler is prepared by the following method: Add mercaptopropyltrimethoxysilane to a 70-80 wt% ethanol aqueous solution, adjust the pH to 3.5±0.5 with glacial acetic acid, and stir for 20-30 minutes; add hydrophilic fumed silica, heat to 65-70° C., stir for 3-4 hours, wash, and dry to obtain mercapto silica; Mercaptosilicon dioxide, azobisisobutyronitrile, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, isobornyl borate and allyltrimethoxysilane are sequentially added into dimethylformamide; the mixture is stirred at 70-75° C. for 3-5 hours, washed and dried to obtain a modified filler.

8. The method for preparing a room temperature end-capped silicone rubber based on 107 rubber according to claim 7, characterized in that: In the raw material of the mercaptosilica, the mass ratio of mercaptopropyltrimethoxysilane to hydrophilic fumed silica is 2 to 5:100; The raw materials of the modified filler include the following components in parts by mass: 50 parts of mercaptosilicon dioxide, 0.1-0.2 parts of azobisisobutyronitrile, 2-3 parts of 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 0.5-1 parts of isobornyl borate, and 2-3 parts of allyltrimethoxysilane.

9. Room temperature end-capped silicone rubber prepared according to the method for preparing room temperature end-capped silicone rubber based on 107 glue according to any one of claims 1 to 8.

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