Silicone sealant as well as preparation method and application thereof

Abstract

The invention discloses a silicone sealant as well as a preparation method and application thereof, and belongs to the technical field of organic silicone sealants. The silicone sealant is prepared from the following components in parts by weight: 60 to 100 parts of hydroxyl-terminated fluorine-containing polysiloxane, 60 to 100 parts of reinforcing filler, 15 to 30 parts of titanate modified filler, 5 to 10 parts of cross-linking agent, 1 to 2 parts of silane coupling agent and 0.05 to 0.15 part of catalyst, the titanate modified filler comprises titanate modified aluminum hydroxide and titanate modified zinc borate. The hydroxyl-terminated fluorine-containing polysiloxane is used as a basic copolymer, and the titanate modified filler and other components are added, so that the silicone sealant still has relatively high strength and adhesive property when working in a high-temperature oil immersion environment for a long time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicone sealant, in particular to a silicone sealant and a preparation method and application thereof. BACKGROUND

[0002] Room temperature vulcanized silicone rubber has excellent performance in aspects of weather resistance, high and low temperature aging resistance, electrical insulation, chemical stability and adhesion to various substrates, and is widely used in bonding and sealing of curtain walls, doors and windows, vehicle lamps, electronic appliances and some corrosion prevention fields. However, when the silicone sealant is used in high temperature environment directly contacting oil such as oil pipeline or automobile engine oil pan, oil is easy to penetrate into the silicone sealant with small polarity of molecular chain, and the molecular chain of the silicone sealant is damaged at high temperature, resulting in significant decrease of the adhesion of the silicone sealant. SUMMARY

[0003] The present application aims to overcome the deficiencies of the prior art, and provide a silicone sealant and a preparation method and application thereof.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: In a first aspect, a silicone sealant is provided, comprising the following components by weight: 60-100 parts of hydroxyl-terminated fluoropolysiloxane, 60-100 parts of reinforcing filler, 15-30 parts of titanate modified filler, 5-10 parts of crosslinking agent, 1-2 parts of silane coupling agent and 0.05-0.15 parts of catalyst. The titanate modified filler comprises titanate modified aluminum hydroxide and titanate modified zinc borate.

[0005] In some embodiments, the particle size D50 of the titanate modified aluminum hydroxide is 1-5 μm, and the particle size D50 of the titanate modified zinc borate is 10-15 μm.

[0006] In some embodiments, the mass ratio of the titanate modified aluminum hydroxide to the titanate modified zinc borate is (1-3):(2-8).

[0007] In some embodiments, the preparation method of the hydroxyl-terminated fluoropolysiloxane comprises the following steps: mixing octamethylcyclotetrasiloxane and alkali catalyst, heating to 80-130℃, then adding trifluoropropylmethylcyclotrisiloxane dropwise, carrying out polymerization reaction, then adding end-capping agent to carry out end-capping, to obtain the hydroxyl-terminated fluoropolysiloxane.

[0008] In some embodiments, the silicone sealant satisfies at least one of the following: (a) the molar ratio of the octamethylcyclotetrasiloxane to the alkali catalyst is (1:500)-(1:2000); (b) the molar ratio of the octamethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane is (1:1)~(1:4); (c) the molar ratio of the base catalyst and the end-capping agent is (1:1)~(1:20); (d) the base catalyst comprises at least one of sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

[0009] In some embodiments, the reinforcing filler comprises at least one of calcium carbonate and hydrophobic silica.

[0010] In some embodiments, the cross-linking agent comprises at least one of methyltris (isopentyloxy) silane, vinyltris (isopentyloxy) silane, methyltris (butanone oxime) silane, and vinyltris (butanone oxime) silane. In some embodiments, the silane coupling agent comprises at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane. In some embodiments, the catalyst comprises at least one of tetramethylguanidine propyltrimethoxysilane, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, and dibutyltin acetylacetonate.

[0011] In some embodiments, the silicone sealant further comprises 1~40 parts by weight of α, ω-dihydroxypolydimethylsiloxane.

[0012] In some embodiments, the α, ω-dihydroxypolydimethylsiloxane has a viscosity of 20000~50000 mPa•s at 25℃.

[0013] In a first aspect, a preparation method of the silicone sealant is provided, comprising the following steps: S1: blending the hydroxyl-terminated fluoropolysiloxane, the reinforcing filler, and the titanate modified filler at a temperature of 110~130℃ and a vacuum degree of -0.09~0.1MPa for 150~200min, and obtaining a base after cooling; S2: adding the cross-linking agent, the silane coupling agent, and the catalyst to the base obtained in step S1, and blending at a temperature of 25~35℃ and a vacuum degree of -0.08~ -0.09MPa for 20~35min, and obtaining the silicone sealant after cooling.

[0014] In a third aspect, the silicone sealant is applied in bonding and sealing of mechanical equipment, corrosion-proof sealing of oil pipelines, or bonding and sealing of indoor buildings resistant to oil and swelling.

[0015] Compared with the prior art, the beneficial effects of the present disclosure are: in the present application, the end-hydroxyl fluorine-containing polysiloxane is used as the base copolymer, the titanate modified filler and other components are added, so that the silicone sealant still has high strength and bonding performance in high-temperature oil immersion environment for a long time. Specifically, the side chain of the end-hydroxyl fluorine-containing polysiloxane contains methyl and trifluoropropyl respectively, which can effectively increase the polarity of the end-hydroxyl fluorine-containing polysiloxane, thereby improving the high-temperature oil resistance of the silicone sealant; the aluminum hydroxide and zinc borate are modified by titanate, which reduces the hydrophilicity of the aluminum hydroxide and zinc borate, improves the dispersibility of the acid ester modified aluminum hydroxide and the titanate modified zinc borate, and also improves the compatibility of the acid ester modified aluminum hydroxide and the titanate modified zinc borate with the end-hydroxyl fluorine-containing polysiloxane, which is beneficial to improve the strength of the silicone sealant; in addition, in the high-temperature oil immersion environment, the acid ester modified aluminum hydroxide can neutralize the acidic substances generated by the reaction of high-temperature oil and the silicone sealant, the acid ester modified zinc borate can generate a dense B2O3 glass layer, the B2O3 layer forms a stable barrier in the oil medium, reduces swelling, and also generates halogen free state with halogen in fluorosilicon copolymer and moisture in the system, captures hydroxyl radicals generated by high molecules, and prevents chain reaction; the two interact with each other to improve the high-temperature oil resistance of the silicone sealant. DETAILED DESCRIPTION

[0016] In order to facilitate the understanding of the present disclosure, the present disclosure will be described more fully below. However, the present disclosure can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure more thorough and comprehensive.

[0017] As used herein, the term: "prepared from" is synonymous with "comprising". The terms "comprising", "including", "having" "with" or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a listed element does not necessarily limit only those elements, but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0018] The conjunction "consisting of" excludes any unrecited elements, steps, or components. If used in a claim, this phrase will close the claim to the addition of any element not specified therein and will, in connection with the described material, be construed as a disavowal of any element not specified. When the phrase "consisting of" appears in a clause of the body of a claim, rather than immediately following a comma following the introductory matter of the claim, it limits only the elements in that clause; other elements not in that clause are not excluded from the claim as a whole.

[0019] When expressing amounts, concentrations, or other values or parameters of a range, preferably a range, or a series of upper preferred values and lower preferred values, it should be understood that all ranges formed by any pair of any upper range limit or preferred value, and any lower range limit or preferred value, are expressly disclosed, even if that range is not explicitly disclosed. For example, where a range "1 to 5" is disclosed, the described range should be interpreted to include ranges of "1 to 4," "1 to 3," "1 to 2," "1 to 2 and 4 to 5," "1 to 3 and 5," etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include both the upper and lower values and all intervening values of the range, as well as any and all subranges thereof.

[0020] In these embodiments, the parts and percentages described are by mass, unless otherwise indicated.

[0021] "Mass parts" refers to a basic unit of measurement that represents the proportional relationship of the mass of multiple components, 1 part can represent any unit mass, such as 1 g, 2.689 g, etc. If we say that the mass parts of component A is a parts, and the mass parts of component B is b parts, it means that the ratio of the mass of component A to the mass of component B is a:b. It should not be misunderstood that, unlike the mass percentage, the sum of the mass parts of all components is not limited to 100 parts.

[0022] "And / or" is used to indicate one or both of the stated circumstances can occur, for example, A and / or B includes (A and B) and (A or B).

[0023] In a first aspect, a silicone sealant is provided, comprising the following components by weight parts: 60-100 parts of a hydroxyl-terminated fluoropolysiloxane, 60-100 parts of a reinforcing filler, 15-30 parts of a titanate-modified filler, 5-10 parts of a crosslinking agent, 1-2 parts of a silane coupling agent, and 0.05-0.15 parts of a catalyst; The titanate-modified filler includes a titanate-modified aluminum hydroxide and / or a titanate-modified zinc borate.

[0024] In the present application, the end-hydroxyl fluorine-containing polysiloxane is used as the base copolymer, the titanate modified filler and other components are added, so that the silicone sealant still has high strength and bonding performance in high temperature oil immersion environment for a long time. Specifically, the side chain of the end-hydroxyl fluorine-containing polysiloxane contains methyl and trifluoropropyl respectively, which can effectively increase the polarity of the silicone sealant, thereby improving the high temperature oil resistance of the silicone sealant; the aluminum hydroxide and / or zinc borate is modified by titanate, which reduces the hydrophilicity of the aluminum hydroxide and the zinc borate, improves the dispersibility of the titanate modified aluminum hydroxide and the titanate modified zinc borate, and also improves the compatibility of the titanate modified aluminum hydroxide and the titanate modified zinc borate with the end-hydroxyl fluorine-containing polysiloxane, which is beneficial to improve the strength of the silicone sealant; in addition, in the high temperature oil immersion environment, the titanate modified aluminum hydroxide can neutralize the acidic substances generated by the reaction of high temperature oil and the silicone sealant, the titanate modified zinc borate can generate a dense B2O3 glass layer, the B2O3 layer forms a stable barrier in the oil medium, reduces swelling, and also generates halogen free state with halogen in fluorosilicon copolymer and moisture in the system, captures hydroxyl radicals generated by high molecules, and prevents chain reaction; the interaction of the two improves the high temperature oil resistance of the silicone sealant.

[0025] Specifically, the weight parts of the end-hydroxyl fluorine-containing polysiloxane can be one or a range value between any two of 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts.

[0026] Specifically, the weight parts of the reinforcing filler can be one or a range value between any two of 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts.

[0027] Specifically, the weight parts of the titanate modified filler can be one or a range value between any two of 15 parts, 17 parts, 19 parts, 21 parts, 23 parts, 25 parts, 28 parts, 30 parts.

[0028] Specifically, the weight parts of the cross-linking agent can be one or a range value between any two of 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts.

[0029] Specifically, the weight parts of the silane coupling agent can be one or a range value between any two of 1 part, 1.1 part, 1.2 part, 1.3 part, 1.4 part, 1.5 part, 1.6 part, 1.7 part, 1.8 part, 1.9 part, 2 parts.

[0030] Specifically, the weight parts of the catalyst can be one or a range value between any two of 0.05 parts, 0.07 parts, 0.09 parts, 0.1 parts, 0.13 parts, 0.15 parts.

[0031] In some embodiments, the mass ratio of the titanate modified aluminum hydroxide and the titanate modified zinc borate is (1-5):(2-10), for example, it can be one of 5:2, 3:2, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or a range value between any two of them; preferably (1-3):(2-8).

[0032] In the present application, the mass ratio of the titanate modified aluminum hydroxide and the titanate modified zinc borate in the above range is beneficial to improve the high-temperature oil resistance of the silicone sealant.

[0033] In some embodiments, the particle size D50 of the titanate modified aluminum hydroxide is 1-5 μm, and the particle size D50 of the titanate modified zinc borate is 10-15 μm.

[0034] In the present application, the titanate modified aluminum hydroxide and the titanate modified zinc borate with the above particle size D50 are used together, which can make the titanate modified filler packing more dense, and further enhance the high-temperature oil resistance of the silicone sealant.

[0035] Specifically, the particle size D50 of the titanate modified aluminum hydroxide can be one of 1 μm, 1.2 μm, 1.5 μm, 1.7 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.3 μm, 4.5 μm, 4.8 μm, 5 μm or a range value between any two of them.

[0036] Specifically, the particle size D50 of the titanate modified zinc borate can be one of 10 μm, 10.3 μm, 10.5 μm, 10.8 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.2 μm, 14.5 μm, 14.7 μm, 15 μm or a range value between any two of them.

[0037] It should be noted that in the present application, the D50 is the particle size of the titanate modified aluminum hydroxide and the titanate modified zinc borate measured by volume particle size distribution, wherein the D50 is the particle size corresponding to the volume cumulative percentage of the material reaching 50%. It should be noted that in the present application, the D50 can be determined by laser diffraction method of particle size analyzer, which can refer to standard GB / T 19077-2016.

[0038] Taking the titanate modified aluminum hydroxide as an example, the preparation method of the titanate modified filler comprises the following steps: The titanate / ethanol solution is added to the aluminum hydroxide, then deionized water is added, and the reaction is carried out at a temperature of 70-90°C for 30-50 min, followed by solid-liquid separation, washing, drying, grinding to obtain the titanate modified aluminum hydroxide.

[0039] Specifically, the volume ratio of titanate and anhydrous ethanol in the titanate / ethanol solution is (0.9-1.1):(0.9-1.1), which can be one of 0.9:0.9, 0.9:1, 0.9:1.1, 1:0.9, 1.1:0.9 or a range value between any two of them.

[0040] Specifically, the mass ratio of aluminum hydroxide and the volume of the titanate / ethanol solution is 1:(4-12) g / mL, which can be one of 1:4 g / mL, 1:6 g / mL, 1:8 g / mL, 1:10 g / mL, 1:12 g / mL or a range value between any two of them.

[0041] Specifically, the volume ratio of the titanate / ethanol solution and deionized water is (0.2-0.6):1, which can be one of 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1 or a range value between any two of them.

[0042] Specifically, the temperature of the reaction can be one of 70℃, 72℃, 75℃, 77℃, 80℃, 83℃, 85℃, 88℃, 90℃ or a range value between any two of them.

[0043] Specifically, the reaction time can be one of 30 min, 35 min, 40 min, 45 min, 50 min or a range value between any two of them.

[0044] Specifically, in order to avoid the influence of moisture on the storage performance of silicone sealant, the zinc borate of the application is anhydrous zinc borate.

[0045] The application obtains titanate modified aluminum hydroxide and titanate modified zinc borate with different particle sizes D50 by changing the grinding time.

[0046] In some embodiments, the method for preparing the terminal hydroxyl-containing fluorosilicone includes the following steps: mixing octamethylcyclotetrasiloxane and base catalyst under inert atmosphere, adding trifluoropropylmethylcyclotrisiloxane after warming to 80-130℃, and then adding a capping agent after polymerization to obtain a terminal hydroxyl-containing fluorosilicone.

[0047] In the application, octamethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane are subjected to anionic ring-opening copolymerization to prepare a terminal hydroxyl-containing fluorosilicone, and the side chains of the terminal hydroxyl-containing fluorosilicone contain methyl and trifluoropropyl groups, which can effectively increase the polarity of the terminal hydroxyl-containing fluorosilicone, thereby improving the high-temperature oil resistance of the silicone sealant.

[0048] In some embodiments, the molar ratio of octamethylcyclotetrasiloxane and base catalyst is (1:500)~(1:2000); for example, it can be one of 1:500, 1:700, 1:900, 1:1000, 1:1200, 1:1400, 1:1600, 1:1800, 1:2000 or a range value between any two of them.

[0049] In some embodiments, the molar ratio of octamethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane is (1:1)~(1:4); for example, it can be one of 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4 or a range value between any two of them.

[0050] In some embodiments, the molar ratio of base catalyst and capping agent is (1:1)~(1:20); for example, it can be one of 1:1, 1:3, 1:5, 1:7, 1:9, 1:11, 1:13, 1:15, 1:17, 1:20 or a range value between any two of them.

[0051] In some embodiments, the base catalyst comprises at least one of sodium hydroxide, potassium hydroxide, ammonium hydroxide.

[0052] In some embodiments, the time for dropping trifluoropropylmethylcyclotrisiloxane is 30-60 min; for example, it can be one of 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min or a range value between any two of them.

[0053] In some embodiments, the time for polymerization reaction is 60-120 min; for example, it can be one of 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min, 100 min, 105 min, 110 min, 115 min, 120 min or a range value between any two of them.

[0054] In some embodiments, the time for capping is 60-120 min; for example, it can be one of 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 95 min, 100 min, 105 min, 110 min, 115 min, 120 min or a range value between any two of them.

[0055] In some embodiments, after the capping is completed, purification treatment is further needed.

[0056] In some embodiments, the purification process comprises extraction and vacuum distillation.

[0057] In some embodiments, the reinforcing filler comprises one of calcium carbonate, hydrophobic silica.

[0058] In some embodiments, the cross-linking agent comprises at least one of methyl tri(isoalkenyl oxy) silane, vinyl tri(isoalkenyl oxy) silane, methyl triketoximino silane, vinyl triketoximino silane.

[0059] In the present application, the cross-linking agent has high hydrolysis ability, which can improve the heat resistance of the silicone sealant.

[0060] In some embodiments, the silane coupling agent comprises at least one of γ-aminopropyl trimethoxysilane, γ-aminopropyl triethoxysilane, γ-glycidoxypropyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane.

[0061] In the present application, the amine-based silane has good adhesion to most materials, and the amine-based silane is alkaline, which can accelerate the vulcanization speed of the silicone sealant. Compared with primary amine-based silane, the paste added with secondary amine-based silane has better storage performance.

[0062] In some embodiments, the catalyst comprises at least one of tetramethyl guanidine propyl trimethoxysilane, dibutyl tin dilaurate, dioctyl tin dilaurate, dibutyl tin diacetate, and dibutyl tin acetylacetone.

[0063] In the present application, the catalyst has good catalytic activity, which is beneficial to the vulcanization of the silicone sealant.

[0064] In some embodiments, the silicone sealant further comprises 1-40 parts by weight of α, ω-dihydroxy polydimethyl siloxane.

[0065] Specifically, the parts by weight of the α, ω-dihydroxy polydimethyl siloxane can be one of 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, or a range value between any two of them.

[0066] In some embodiments, the α, ω-dihydroxy polydimethyl siloxane has a viscosity of 20,000-50,000 mPa•s at 25°C; for example, it can be one of 20,000 mPa•s, 25,000 mPa•s, 30,000 mPa•s, 35,000 mPa•s, 40,000 mPa•s, 45,000 mPa•s, 50,000 mPa•s, or a range value between any two of them.

[0067] In a second aspect, a preparation method of the silicone sealant is provided, comprising the following steps: S1: blending the hydroxyl-terminated fluoropolysiloxane, the reinforcing filler and the titanate modified filler at a temperature of 110-130 DEG C and a vacuum degree of -0.09-0.1 MPa for 150-200 min, and obtaining a base after cooling; S2: adding the crosslinking agent, the silane coupling agent and the catalyst to the base obtained in step S1, and blending at a temperature of 25-35 DEG C and a vacuum degree of -0.08--0.09 MPa for 20-35 min, and obtaining the silicone sealant after cooling.

[0068] In a third aspect, the silicone sealant is applied in the bonding and sealing of mechanical equipment, the corrosion-proof sealing of oil pipelines, or the bonding and sealing of indoor buildings resistant to oil and swelling.

[0069] The hydroxyl-terminated fluoropolysiloxane A is self-made, and the preparation method is as follows: Under a nitrogen atmosphere, octamethylcyclotetrasiloxane and potassium hydroxide are added into a container and uniformly mixed, and then the temperature is raised to 100 DEG C, and trifluoropropylmethylcyclotrisiloxane is added dropwise, the dropwise adding time is 45 min, after the dropwise adding is completed, the reaction is maintained for 90 min, then deionized water is added, and the reaction is continued for 90 min, and the reaction is terminated; the product obtained by the reaction is extracted with cyclohexane for 5 times, and then low-boiling substances are removed by distillation under reduced pressure, to obtain the hydroxyl-terminated fluoropolysiloxane A; The molar ratio of octamethylcyclotetrasiloxane to potassium hydroxide is 1:1000, The molar ratio of octamethylcyclotetrasiloxane to trifluoropropylmethylcyclotrisiloxane is 1:2; The molar ratio of potassium hydroxide to deionized water is 1:10.

[0070] The hydroxyl-terminated fluoropolysiloxane B is self-made, and the preparation method is as follows: Under a nitrogen atmosphere, octamethylcyclotetrasiloxane and potassium hydroxide are added into a container and uniformly mixed, and then the temperature is raised to 80 DEG C, and trifluoropropylmethylcyclotrisiloxane is added dropwise, the dropwise adding time is 60 min, after the dropwise adding is completed, the reaction is maintained for 120 min, then deionized water is added, and the reaction is continued for 120 min, and the reaction is terminated; the product obtained by the reaction is extracted with cyclohexane for 3 times, and then low-boiling substances are removed by distillation under reduced pressure, to obtain the hydroxyl-terminated fluoropolysiloxane A; The molar ratio of octamethylcyclotetrasiloxane to potassium hydroxide is 1:2000, The molar ratio of octamethylcyclotetrasiloxane to trifluoropropylmethylcyclotrisiloxane is 1:1; The molar ratio of potassium hydroxide to deionized water is 1:1.

[0071] The hydroxyl-terminated fluoropolysiloxane C is self-made, and the preparation method is as follows: Under a nitrogen atmosphere, octamethylcyclotetrasiloxane and potassium hydroxide were added to a container and mixed thoroughly. The mixture was heated to 130°C, and then trifluoropropylmethylcyclotrisiloxane was added dropwise over a period of 30 min. After the addition was complete, the mixture was kept at the temperature for another 30 min. Then, deionized water was added, and the reaction was continued for another 60 min to terminate the reaction. The product obtained was extracted five times with cyclohexane, and then low-boiling substances were removed by vacuum distillation to obtain hydroxyl-terminated fluorinated polysiloxane A. The molar ratio of octamethylcyclotetrasiloxane to potassium hydroxide is 1:500. The molar ratio of octamethylcyclotetrasiloxane to trifluoropropylmethylcyclotrisiloxane is 1:4; The molar ratio of potassium hydroxide to deionized water is 1:20.

[0072] The titanate-modified aluminum hydroxide was prepared in-house. The preparation method was as follows: a titanate / ethanol solution was added to aluminum hydroxide, followed by the addition of deionized water. The mixture was reacted at 70°C for 50 minutes. After solid-liquid separation, washing, drying, and grinding, titanate-modified aluminum hydroxide was obtained. In the titanate / ethanol solution, the volume ratio of titanate to anhydrous ethanol is 1:1. The mass ratio of aluminum hydroxide to the volume ratio of titanate / ethanol solution is 1:4 g / mL; The volume ratio of titanate / ethanol solution to deionized water is 0.2:1.

[0073] The titanate-modified zinc borate was prepared in-house. The preparation method was as follows: titanate / ethanol solution was added to anhydrous zinc borate, followed by the addition of deionized water. The mixture was reacted at 90°C for 30 minutes. After solid-liquid separation, washing, drying, and grinding, titanate-modified zinc borate was obtained. In the titanate / ethanol solution, the volume ratio of titanate to anhydrous ethanol is 1:1. The mass ratio of zinc borate to the volume ratio of titanate / ethanol solution is 1:12 g / mL; The volume ratio of titanate / ethanol solution to deionized water is 0.6:1.

[0074] The titanate-modified aluminum oxide was prepared in-house. The only difference between its preparation method and that of titanate-modified aluminum hydroxide is that aluminum oxide is used instead of aluminum hydroxide.

[0075] The titanate-modified zinc carbonate was prepared in-house. The only difference between its preparation method and that of titanate-modified zinc borate is that zinc carbonate is used instead of zinc borate.

[0076] Example 1 The embodiment provides a silicone sealant, which comprises the following components in parts by weight: 80 parts of hydroxyl-terminated fluoropolysiloxane A, 80 parts of calcium carbonate, 22 parts of titanate modified filler, 10 parts of methyl tri (isopropenyl oxy) silane, 1.5 parts of gamma-aminopropyl trimethoxysilane and 0.1 part of tetramethyl guanidine propyl trimethoxysilane; The titanate modified filler is titanate modified aluminum hydroxide and titanate modified zinc borate, the mass ratio of the titanate modified aluminum hydroxide and the titanate modified zinc borate is 1:4, the particle size D50 of the titanate modified aluminum hydroxide is 3 μm, and the particle size D50 of the titanate modified zinc borate is 13 μm.

[0077] The preparation method of the silicone sealant in the embodiment comprises the following steps: S1: blending the hydroxyl-terminated fluoropolysiloxane A, the calcium carbonate and the titanate modified filler under the condition that the temperature is 120 DEG C and the vacuum degree is -0.09 MPa for 180 min, and obtaining a base after cooling; S2: adding the methyl tri (isopropenyl oxy) silane into the base obtained in the step S1, blending under the condition that the temperature is 25 DEG C and the vacuum degree is -0.09 MPa for 10 min, then adding the gamma-aminopropyl trimethoxysilane and the tetramethyl guanidine propyl trimethoxysilane, and blending under the condition that the temperature is 25 DEG C and the vacuum degree is -0.09 MPa for 10 min to obtain the silicone sealant.

[0078] Embodiment 2 The embodiment provides a silicone sealant, which comprises the following components in parts by weight: 100 parts of hydroxyl-terminated fluoropolysiloxane B, 70 parts of calcium carbonate, 5 parts of hydrophobic silicon dioxide, 30 parts of titanate modified filler, 8 parts of methyl tributanone oxime silane, 1 part of gamma-glycidyl ether oxypropyl trimethoxysilane and 0.05 part of dibutyl tin dilaurylate; The titanate modified filler is titanate modified aluminum hydroxide and titanate modified zinc borate, the mass ratio of the titanate modified aluminum hydroxide and the titanate modified zinc borate is 1:4, the particle size D50 of the titanate modified aluminum hydroxide is 3 μm, and the particle size D50 of the titanate modified zinc borate is 13 μm.

[0079] The preparation method of the silicone sealant in the embodiment comprises the following steps: S1: blending the hydroxyl-terminated fluoropolysiloxane B, the calcium carbonate, the hydrophobic silicon dioxide and the titanate modified filler under the condition that the temperature is 110 DEG C and the vacuum degree is 0.1 MPa for 200 min, and obtaining a base after cooling; S2: adding methyltris(butanone oxime)silane to the base material obtained in step S1, blending for 20 min under the condition of temperature 30℃ and vacuum degree-0.09MPa, then adding γ-glycidoxypropyltrimethoxysilane and dibutyltin dilaurate, blending for 15 min under the condition of temperature 30℃ and vacuum degree-0.09MPa, and obtaining silicone sealant after cooling.

[0080] Example 3 The example provides a silicone sealant, which comprises the following components in parts by weight: 60 parts of hydroxyl-terminated fluoropolysiloxane C, 40 parts of α, ω-dihydroxypolydimethylsiloxane, 100 parts of calcium carbonate, 15 parts of titanate modified filler, 5 parts of methyltris(butanone oxime)silane, 2 parts of γ-aminopropyltrimethoxysilane and 0.15 parts of tetramethylguanidinopropyltrimethoxysilane. The α, ω-dihydroxypolydimethylsiloxane has a viscosity of 30000 mPa•s at 25℃, the titanate modified filler is titanate modified aluminum hydroxide and titanate modified zinc borate, the mass ratio of the titanate modified aluminum hydroxide to the titanate modified zinc borate is 1:4, the particle size D50 of the titanate modified aluminum hydroxide is 3μm, and the particle size D50 of the titanate modified zinc borate is 13μm.

[0081] The example provides a silicone sealant, which comprises the following components in parts by weight: 60 parts of hydroxyl-terminated fluoropolysiloxane C, 40 parts of α, ω-dihydroxypolydimethylsiloxane, 100 parts of calcium carbonate, 15 parts of titanate modified filler, 5 parts of methyltris(butanone oxime)silane, 2 parts of γ-aminopropyltrimethoxysilane and 0.15 parts of tetramethylguanidinopropyltrimethoxysilane. S1: blending hydroxyl-terminated fluoropolysiloxane C, α, ω-dihydroxypolydimethylsiloxane, calcium carbonate and titanate modified filler under the condition of temperature 130℃ and vacuum degree-0.09MPa for 180 min, and obtaining a base material after cooling; S2: adding methyltris(butanone oxime)silane to the base material obtained in step S1, blending for 20 min under the condition of temperature 30℃ and vacuum degree-0.09MPa, then adding γ-glycidoxypropyltrimethoxysilane and dibutyltin dilaurate, blending for 15 min under the condition of temperature 30℃ and vacuum degree-0.09MPa, and obtaining silicone sealant after cooling.

[0082] Example 4 The example provides a silicone sealant, which is different from example 1 only in that the particle size D50 of the titanate modified aluminum hydroxide is 5μm, and the particle size D50 of the titanate modified zinc borate is 10μm.

[0083] Example 5 The example provides a silicone sealant, which is different from example 1 only in that the particle size D50 of the titanate modified aluminum hydroxide is 1μm, and the particle size D50 of the titanate modified zinc borate is 15μm.

[0084] Example 6 This example provides a silicone sealant which is different from Example 1 only in that the particle size D50 of the titanate-modified aluminum hydroxide is 13 μm and the particle size D50 of the titanate-modified zinc borate is 3 μm.

[0085] Example 7 This example provides a silicone sealant which is different from Example 1 only in that the particle size D50 of the titanate-modified aluminum hydroxide is 0.5 μm and the particle size D50 of the titanate-modified zinc borate is 20 μm.

[0086] Example 8 This example provides a silicone sealant which is different from Example 1 only in that the mass ratio of the titanate-modified aluminum hydroxide and the titanate-modified zinc borate is 3:2.

[0087] Example 9 This example provides a silicone sealant which is different from Example 1 only in that the mass ratio of the titanate-modified aluminum hydroxide and the titanate-modified zinc borate is 1:8.

[0088] Example 10 This example provides a silicone sealant which is different from Example 1 only in that the mass ratio of the titanate-modified aluminum hydroxide and the titanate-modified zinc borate is 5:2.

[0089] Example 11 This example provides a silicone sealant which is different from Example 1 only in that the mass ratio of the titanate-modified aluminum hydroxide and the titanate-modified zinc borate is 1:10.

[0090] Example 12 This example provides a silicone sealant which is different from Example 1 only in that the titanate-modified filler is a titanate-modified aluminum hydroxide.

[0091] Example 13 This example provides a silicone sealant which is different from Example 1 only in that the titanate-modified filler is a titanate-modified zinc borate.

[0092] Comparative Example 1 This comparative example provides a silicone sealant which is different from Example 1 only in that the filler is not titanate-modified, i.e., the titanate-modified aluminum hydroxide is replaced by aluminum hydroxide and the titanate-modified zinc borate is replaced by anhydrous zinc borate.

[0093] Comparative Example 2 This comparative example provides a silicone sealant which is different from Example 1 only in that the titanate-modified filler is a titanate-modified aluminum trioxide.

[0094] Comparative Example 3 This comparative example provides a silicone sealant which is only different from Example 1 in that the titanate modified filler is replaced by a titanate modified zinc carbonate.

[0095] Comparative Example 4 This comparative example provides a silicone sealant which is only different from Example 12 in that the titanate modified filler is replaced by a silane coupling agent modified zinc borate; wherein the silane coupling agent modified zinc borate is prepared by adding 100 parts by weight of zinc borate and 0.5 parts by weight of γ-aminopropyltrimethoxysilane into 150 parts by weight of deionized water, reacting at a temperature of 70°C for 50 min, and then performing solid-liquid separation, washing, drying, and grinding to obtain the silane coupling agent modified zinc borate.

[0096] Comparative Example 5 This comparative example provides a silicone sealant which is only different from Example 12 in that the titanate modified filler is replaced by a silane coupling agent modified aluminum hydroxide; wherein the silane coupling agent modified aluminum hydroxide is prepared by adding 100 parts by weight of aluminum hydroxide and 0.5 parts by weight of γ-aminopropyltrimethoxysilane into 150 parts by weight of deionized water, reacting at a temperature of 70°C for 50 min, and then performing solid-liquid separation, washing, drying, and grinding to obtain the silane coupling agent modified aluminum hydroxide.

[0097] Comparative Example 6 This comparative example provides a silicone sealant which is only different from Example 1 in that the titanate modified aluminum hydroxide is replaced by a hexamethyldisilazane surface treated hydrophobic fumed silica, and the hexamethyldisilazane surface treated hydrophobic fumed silica is AEROSIL R812 from DeGussa.

[0098] Comparative Example 7 This comparative example provides a silicone sealant which is only different from Example 1 in that the titanate modified zinc borate is replaced by basic zinc carbonate, and the basic zinc carbonate is purchased from Shenzhen Jingcai Chemical Co., Ltd.

[0099] Performance Test The performance of the silicone sealants obtained from the examples and comparative examples is tested, and the testing method is as follows: (1) Strength: The silicone sealant is injected into a mold frame, scraped into a film, and cured for seven days under standard conditions of temperature (23±2) °C and humidity (50±5%); then the film is sampled and tested for tensile strength according to GB / T 528-2009; (2) Elongation at break: The silicone sealant is injected into a mold frame, scraped into a film, and cured for seven days under standard conditions of temperature (23±2) °C and humidity (50±5%); then the film is sampled and tested for elongation at break according to GB / T 528-2009; (3) Heat resistance: the silicone sealant is injected into the mold frame, scraped into a film, and after curing for seven days at a standard temperature (23±2) °C and humidity (50±5%), the film is heated and aged at 180 °C for 192 h, and after cooling to room temperature, the tensile strength and elongation at break are tested according to GB / T 528-2009; (4) Oil resistance: the silicone sealant is injected into the mold frame, scraped into a film, and after curing for seven days at a standard temperature (23±2) °C and humidity (50±5%), the film is completely immersed in automobile lubricating oil and heated and aged at 150 °C for 312 h, and then the tensile strength and elongation at break are tested according to GB / T 528-2009.

[0100] The performance change rate = [1- (data after aging / data before aging)] * 100%; the test results are shown in Table 1 below; The high-temperature oil aging strength attenuation rate is ≤25%, and the elongation at break attenuation rate is ≤5%; the high-temperature aging strength attenuation rate is ≤5%, and the elongation at break attenuation rate is ≤25%.

[0101] Table 1 Finally, it should be noted that the above examples are used to illustrate the technical solutions of the present disclosure and are not intended to limit the scope of protection of the present disclosure. Although the present disclosure has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present disclosure can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present disclosure.

Claims

1. A silicone sealant, characterized in that, It comprises the following components in parts by weight: 60-100 parts of hydroxyl-terminated fluorinated polysiloxane, 60-100 parts of reinforcing filler, 15-30 parts of titanate modified filler, 5-10 parts of crosslinking agent, 1-2 parts of silane coupling agent and 0.05-0.15 parts of catalyst. The titanate-modified filler includes titanate-modified aluminum hydroxide and / or titanate-modified zinc borate.

2. The silicone sealant as described in claim 1, characterized in that, The modified filler is titanate-modified aluminum hydroxide and titanate-modified zinc borate; the mass ratio of titanate-modified aluminum hydroxide and titanate-modified zinc borate is (1~5):(2~10).

3. The silicone sealant as described in claim 1, characterized in that, The particle size D50 of the titanate-modified aluminum hydroxide is 1~5μm, and the particle size D50 of the titanate-modified zinc borate is 10~15μm.

4. The silicone sealant as described in claim 1, characterized in that, The preparation method of the hydroxyl-terminated fluorinated polysiloxane includes the following steps: mixing octamethylcyclotetrasiloxane and an alkaline catalyst, heating to 80~130℃, adding trifluoropropylmethylcyclotrisiloxane dropwise, carrying out a polymerization reaction, adding a capping agent, and capping to obtain hydroxyl-terminated fluorinated polysiloxane.

5. The silicone sealant as described in claim 4, characterized in that, Meet at least one of the following: (a) The molar ratio of the octamethylcyclotetrasiloxane to the base catalyst is (1:500) to (1:2000). (b) The molar ratio of the octamethylcyclotetrasiloxane and trifluoropropylmethylcyclotrisiloxane is (1:1) to (1:4). (c) The molar ratio of the alkaline catalyst to the end-capping agent is (1:1) to (1:20). (d) The alkaline catalyst includes at least one of sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

6. The silicone sealant as described in claim 1, characterized in that, The reinforcing filler includes one of calcium carbonate and hydrophobic silica. And / or, the crosslinking agent includes at least one of methyltris(isoallyloxy)silane, vinyltris(isoallyloxy)silane, methyltributylone oxime silane, and vinyltributylone oxime silane; And / or, the silane coupling agent comprises at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; And / or, the catalyst comprises at least one of tetramethylguanidinopropyltrimethoxysilane, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, and dibutyltin acetylacetonate.

7. The silicone sealant as described in claim 1, characterized in that, The silicone sealant also includes 1 to 40 parts by weight of α,ω-dihydroxypolydimethylsiloxane.

8. The silicone sealant as described in claim 7, characterized in that, The viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25°C is 20,000 ~ 50,000 mPa•s.

9. A method for preparing a silicone sealant as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Hydroxyl-terminated fluorinated polysiloxane, reinforcing filler and titanate modified filler are blended at a temperature of 110~130℃ and a vacuum degree of -0.09~0.1MPa for 150~200min, and the base material is obtained after cooling; S2: Add crosslinking agent, silane coupling agent and catalyst to the base material obtained in step S1, and mix for 20 to 35 minutes at a temperature of 25~35℃ and a vacuum degree of -0.08~-0.09MPa. After cooling, silicone sealant is obtained.

10. The application of the silicone sealant as described in any one of claims 1 to 8 in the bonding and sealing of mechanical equipment, the anti-corrosion sealing of oil pipelines, or the bonding and sealing of indoor buildings that are oil-resistant and resistant to swelling.

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