Modified fluorosilicone crosslinker, two-component silicone sealant and preparation method thereof

Abstract

The application discloses a modified fluorosilicone crosslinking agent, a two-component silicone sealant and a preparation method thereof. The structural formula of the modified fluorosilicone crosslinking agent is as follows. The two-component silicone sealant is added with the modified fluorosilicone crosslinking agent. The two-component silicone sealant prepared by using the modified fluorosilicone compound provided by the application as a crosslinking agent and cooperating with conventional crosslinking agents, coupling agents and other components solves the performance defects of the existing silicone sealant under long-term high-temperature and immersion conditions, effectively improves the strength of the sealant, and significantly improves the high-temperature tensile retention rate of the sealant and the bonding performance after water-ultraviolet light irradiation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sealant, in particular to a silicone sealant, and more particularly to a modified fluorosilicon crosslinking agent, a two-component silicone sealant and a preparation method thereof. BACKGROUND

[0002] Condensation type two-component room temperature vulcanized (RTV-2) silicone sealant can quickly crosslink to form an elastomer with certain hardness at room temperature. It is currently a main product of sealing material and is widely used in the fields of construction and industry. Silane crosslinking agent is an important component of the sealant, which affects the curing performance and adhesion performance of the sealant. Its application in composite materials has been widely recognized, and has a great influence on the adhesion strength, water resistance and weather resistance of the base material.

[0003] At present, the commonly used two-component silicone sealant is limited in specific conditions, such as long-term high temperature and immersion conditions, and its mechanical properties and tensile adhesion will be adversely affected. Patent CN202210877362.3 uses formula optimization to obtain a two-component high-temperature-resistant high-shear-strength organic silicone adhesive, but the formula contains a large amount of organosilicon polysilazane, which has a high formula cost and is not conducive to industrialization. Patent CN202410084455.X mixes organosiloxane / accelerator dibutyltin dilaurate / crosslinking agent tetraethyl orthosilicate, so that the three react with each other to generate a new mixed adhesive. Then, bamboo fibers are added to the mixed adhesive in a specified proportion to improve the high-temperature resistance of the two-component silicone adhesive. Patent CN202310785475.5 uses a specific treated calcium carbonate and a conventional coupling agent obtained by reaction under specific conditions to improve the water immersion and water ultraviolet aging resistance of the sealant. The synthesis process is complicated and only improves a single property, which is limited in multiple special conditions.

[0004] Therefore, it is necessary to improve the heat resistance and water immersion adhesion of the two-component silicone sealant to expand the application of the sealant under more stringent conditions. SUMMARY

[0005] Based on this, the purpose of the present application is to provide a two-component silicone sealant with good heat resistance and excellent water immersion adhesion.

[0006] In order to achieve the above purpose, the present application includes the following technical solutions.

[0007] In a first aspect, the present application provides a modified fluorosilicon compound, which has the following structural formula:

[0008]

[0009] wherein n is 4, 8 or 12.

[0010] In a second aspect, the present application provides a method for preparing the modified fluorosilicon compound, comprising the following steps: under the protection of inert gas, dehydrogenation condensation reaction of α,ω-hydroxyl polymethyl trifluoropropyl siloxane and dimethoxy phenyl silane under the catalysis of palladium-carbon catalyst, to obtain the modified fluorosilicon compound.

[0011] The reaction formula is as follows:

[0012]

[0013] Wherein, n is 4, 8 or 12.

[0014] In a third aspect, the present application provides an application of the modified fluorosilicon compound as a crosslinking agent in preparing a two-component silicone sealant.

[0015] In a fourth aspect, the present application provides a two-component silicone sealant, wherein the crosslinking agent contains the modified fluorosilicon compound.

[0016] Preferably, the crosslinking agent is composed of a first crosslinking agent and a second crosslinking agent, the first crosslinking agent is the modified fluorosilicon compound, and the second crosslinking agent is selected from one or more combinations of tetraethyl orthosilicate, tetrapropyl orthosilicate, polyethyl silicate, methyl trimethoxy silane, methyl triethoxy silane, vinyl trimethoxy silane, polymethyl triethoxy silane oligomer, phenyl trimethoxy silane, phenyl triethoxy silane, methyl phenyl dimethoxy silane, methyl phenyl diethoxy silane, diphenyl dimethoxy silane and diphenyl diethoxy silane.

[0017] Preferably, the two-component silicone sealant is composed of component A and component B, wherein the component A is prepared from raw materials including the following components:

[0018] α,ω-dihydroxyl polydimethyl siloxane 100 parts

[0019] Filler 60-150 parts

[0020] Dimethyl silicone oil 5-25 parts

[0021] The component B is prepared from raw materials including the following components:

[0022]

[0023] In a fifth aspect, the present application provides a method for preparing the two-component silicone sealant, comprising the following steps:

[0024] Preparation of A component: the alpha, omega-dihydroxyl polydimethylsiloxane, dimethyl silicone oil and filler are mixed at a temperature of 60-120 DEG C under stirring for 10-200 minutes to obtain A component;

[0025] Preparation of B component: the dimethyl silicone oil and carbon black are mixed at a temperature of 80-120 DEG C under vacuum stirring for 10-60 minutes, and then cooled to room temperature, and then the second cross-linking agent, coupling agent, first cross-linking agent and catalyst are added and stirred for 10-200 minutes under inert gas protection to obtain B component.

[0026] The present application has the following beneficial effects:

[0027] In view of the problems of performance attenuation of traditional two-component silicone sealant at high temperature and poor water immersion performance, the modified fluorosilicon compound with multiple benzene ring side groups is prepared by dehydrogenation condensation of dimethoxyphenylsilane and low molecular weight alpha, omega-hydroxyl polymethyl trifluoropropyl siloxane under the catalysis of palladium-carbon catalyst, and the compound can be added into the two-component silicone sealant as a cross-linking agent, so that the heat resistance and water immersion adhesion of the two-component silicone sealant can be improved.

[0028] The two-component silicone sealant prepared by using the modified fluorosilicon compound provided by the present application as a cross-linking agent in combination with conventional cross-linking agent, coupling agent and other components can solve the performance defects of the existing silicone sealant under long-term high temperature and water immersion conditions, effectively improve the strength of the sealant, and significantly improve the high-temperature tensile retention rate of the sealant and the adhesion performance after water-ultraviolet light irradiation.

[0029] The synthesis process of the modified fluorosilicon compound is simple, the product yield is high, the catalyst and solvent can be recycled, the post-treatment process is simple, and the present application is suitable for industrial production. DETAILED DESCRIPTION

[0030] The technical solutions of the present application are further illustrated below by specific examples. Those skilled in the art should understand that the examples are only used to help understand the present application, and should not be regarded as specific limitations on the present application.

[0031] Unless otherwise defined, all technical and scientific terms used in the present application have the same meanings as commonly understood by those skilled in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific examples, and are not used to limit the present application.

[0032] The terms "comprising" and "having" and any variations thereof herein are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of steps or modules is not necessarily limited to those listed steps or modules, but can include additional steps or modules not expressly listed or additional steps or modules that are inherent to such process, method, article, or apparatus.

[0033] "Multiple" mentioned in the present application refers to two or more. "And / or", which describes the association relationship of associated objects, means that there can be three relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. The character " / " generally represents that the associated objects before and after it are in an "or" relationship.

[0034] Some embodiments of the present application relate to a modified fluorosilicon compound, which has the following structural formula:

[0035]

[0036] Wherein, n is 4, 8 or 12.

[0037] In some embodiments of the present application, a preparation method of a modified fluorosilicon compound is disclosed, comprising the following steps: under the protection of inert gas, α, ω-terminated hydroxyl polymethyl trifluoropropyl siloxane and dimethoxy phenyl silane are subjected to dehydrogenation condensation reaction under the catalysis of palladium-carbon catalyst, so as to obtain the modified fluorosilicon compound.

[0038]

[0039] The reaction formula is as follows:

[0040] Wherein, n is 4, 8 or 12.

[0041] In some embodiments, the molar ratio of the α, ω-terminated hydroxyl polymethyl trifluoropropyl siloxane and the dimethoxy phenyl silane is 1:2-4.

[0042] In some embodiments, the ratio of the α, ω-terminated hydroxyl polymethyl trifluoropropyl siloxane to the palladium-carbon catalyst is 1 mol:3g-5g.

[0043] In some embodiments, the reaction is carried out in an organic solvent, and the organic solvent is preferably tetrahydrofuran.

[0044] In some embodiments, the temperature of the reaction is 50-70°C, and the time is 6-12 hours.

[0045] In some embodiments, the temperature of the reaction is 55-65°C, and the time is 7-9 hours.

[0046] In some embodiments of the present application, the modified fluorosilicon compound is used as a crosslinking agent in preparing a two-component silicone sealant.

[0047] In some embodiments of the present application, a two-component silicone sealant is provided, wherein the crosslinking agent contains the modified fluorosilicon compound of the present application.

[0048] In some embodiments, the crosslinking agent is composed of a first crosslinking agent and a second crosslinking agent, wherein the first crosslinking agent is the modified fluorosilicon compound of the present application, and the second crosslinking agent is selected from one or more of the following: tetraethyl orthosilicate, tetrapropyl orthosilicate, polyethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, polymethyltriethoxysilane oligomer, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

[0049] In some embodiments, the mass ratio of the first crosslinking agent to the second crosslinking agent is 2-10: 15-60.

[0050] In some embodiments, the mass ratio of the first crosslinking agent to the second crosslinking agent is 3-9: 45-55.

[0051] In some embodiments, the mass ratio of the first crosslinking agent to the second crosslinking agent is 4-9: 48-52.

[0052] In some embodiments, the mass ratio of the first crosslinking agent to the second crosslinking agent is 4-7: 48-52.

[0053] In some embodiments, the mass ratio of the first crosslinking agent to the second crosslinking agent is 5-7: 50.

[0054] In some embodiments, the two-component silicone sealant is composed of component A and component B, wherein the component A is prepared from raw materials including the following components:

[0055] α, ω-dihydroxypolydimethylsiloxane 100 parts

[0056] Filler 60-150 parts

[0057] Dimethyl silicone oil 5-25 parts;

[0058] The component B is prepared from raw materials including the following components:

[0059]

[0060] In some embodiments, the A component is prepared from raw materials including the following components by weight parts:

[0061] α,ω-dihydroxypolydimethylsiloxane 100 parts

[0062] filler 90-110 parts

[0063] dimethyl silicone oil 8-12 parts;

[0064] The B component is prepared from raw materials including the following components by weight parts:

[0065]

[0066] In some embodiments, the weight parts of the first crosslinking agent is 4-9 parts.

[0067] In some embodiments, the weight parts of the first crosslinking agent is 4-7 parts.

[0068] In some embodiments, the weight parts of the first crosslinking agent is 5-7 parts.

[0069] In some embodiments, the weight parts of the first crosslinking agent is 6 parts.

[0070] In some embodiments, the weight parts of the second crosslinking agent is 48-52 parts.

[0071] In some embodiments, the weight parts of the coupling agent is 48-52 parts.

[0072] In some embodiments, the mixed volume ratio of the A component and the B component is 8-12:1 when used.

[0073] In some embodiments, the viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25°C is 5000-80000 mPa·s, preferably 1000-20000 mPa·s, and more preferably 18000-20000 mPa·s.

[0074] In some embodiments, the filler is nano-active calcium carbonate with a particle size of 20-200 nm, preferably 60-85 nm, and more preferably 78-82 nm.

[0075] In some embodiments, the viscosity of the dimethyl silicone oil in the A component at 25°C is 300-1000 mPa·s, preferably 350-500 mPa·s.

[0076] In some embodiments, the dimethicone in the B component has a viscosity of 5000 mPa s to 15000 mPa s at 25°C, preferably 8000 mPa s to 12000 mPa s.

[0077] In some embodiments, the coupling agent is selected from at least one of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, epoxycyclohexylmethyl dimethoxysilane, epoxycyclohexylmethyl diethoxysilane, chloropropyltrimethoxysilane, chloropropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, phenylaminomethyltrimethoxysilane, phenylaminomethyltriethoxysilane, γ-isocyanatopropyltrimethoxysilane, epoxycyclohexyltrimethoxysilane, divinyltriaminopropyltrimethoxysilane.

[0078] In some embodiments, the catalyst is selected from at least one of dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, isopropyl titanate and n-butyl titanate.

[0079] In some embodiments of the present application, a method for preparing the two-component silicone sealant is provided, comprising the following steps:

[0080] Preparation of the A component: the α,ω-dihydroxypolydimethylsiloxane, dimethicone and nano active calcium carbonate are mixed at a temperature of 60°C to 120°C under stirring for 10 min to 200 min to obtain the A component;

[0081] Preparation of the B component: the dimethicone and carbon black are mixed at a temperature of 80°C to 120°C under vacuum stirring for 10 min to 60 min, and then the second crosslinking agent, coupling agent, first crosslinking agent and catalyst are added and stirred for 10 min to 200 min under inert gas protection to obtain the B component.

[0082] In some embodiments, the method for preparing the two-component silicone sealant comprises the following steps:

[0083] Preparation of the A component: the α,ω-dihydroxypolydimethylsiloxane, dimethicone and filler are mixed at a temperature of 80°C to 100°C under stirring for 40 min to 90 min to obtain the A component;

[0084] Preparation of B component: the dimethyl silicone oil and carbon black are vacuum stirred at a temperature of 90-110°C for 20-40 minutes, cooled to room temperature, and then the second crosslinking agent, coupling agent, first crosslinking agent and catalyst are added, stirred for 10-30 minutes under inert gas protection, to obtain B component.

[0085] In some embodiments, the vacuum degree of the vacuum stirring is -0.08 MPa to -0.095 MPa.

[0086] The following are specific embodiments.

[0087] The viscosity in the following examples refers to the viscosity at 25°C unless otherwise specified; the "parts" refer to weight parts unless otherwise specified, and the room temperature refers to a temperature range of 15-30°C.

[0088] The preparation method of the multi-benzene ring side group modified fluorosilicon crosslinking agent in the following examples is as follows:

[0089] A three-necked flask equipped with a condensation reflux device and a tetrafluoroethylene stirring paddle is connected to a nitrogen inlet and outlet, and high-purity nitrogen is introduced. 0.1 mol of α, ω-hydroxyl poly-methyl trifluoropropyl siloxane, 150 mL of tetrahydrofuran, and 0.4 g of palladium-carbon catalyst are sequentially added to the flask, stirred uniformly, and heated to 60°C, then 0.3 mol of dimethoxyphenyl silane is added, and the reaction is continued at 60°C for 8 hours. After the reaction is completed, the temperature is lowered to room temperature, and the palladium-carbon catalyst in the mixture is removed by suction filtration through a Buchner funnel. The solvent in the filtered mixture is then removed by rotary evaporation under vacuum at 80°C, to obtain a crude product of the multi-benzene ring side group modified fluorosilicon crosslinking agent. The crude product is then heated to 130°C, stirred, and vacuumed to remove unreacted dimethoxyphenyl silane, and the obtained liquid is the target product, the multi-benzene ring side group modified fluorosilicon crosslinking agent, with a yield of 93%. The reaction formula is as follows:

[0090]

[0091] wherein n is 4.

[0092] The infrared data of the product are characterized: no silicon hydroxyl stretching vibration peak is found at 3710 cm -1 , proving that the dehydrogenation reaction between silicon hydrogen and silicon hydroxyl is complete; Si-OCH3 characteristic peaks are found at 2850 cm -1 and 1094 cm -1 , proving that the target product is successfully synthesized.

[0093] Example 1: Preparation of two-component silicone sealant

[0094] Preparation of A component:

[0095] Take 100 parts of viscosity 10000 mPa·s of α, ω-dihydroxy polydimethylsiloxane and 10 parts of viscosity 400 mPa·s of dimethyl silicone oil into a kneader to stir and disperse, after 5 minutes, add 100 parts of nano active calcium carbonate with a particle size of 80 nm in the stirring process, make the glue completely cover the powder to form a self-leveling type base, control the reaction temperature to be 90℃, stir and mix for 1h, get the A component, grind and reserve.

[0096] Preparation of B component:

[0097] Put 100 parts of dimethyl silicone oil with viscosity 10000 mPa·s and 100 parts of carbon black into a planetary machine, stir under vacuum (-0.09Mpa), wait for the temperature to stabilize at 100℃, stir for 30min, get B base; cool to room temperature, then add 30 parts of propyl trimethoxysilane, 20 parts of methyl trimethoxysilane, 30 parts of γ-aminopropyl trimethoxysilane, 20 parts of γ-glycidyl ether oxygen propyl trimethoxysilane, 3 parts of polycyclic side group modified fluorosilicon crosslinking agent and 1 part of dibutyltin dilaurate, stir for 20min under nitrogen protection, get B component, seal and store.

[0098] When used, mix A component and B component uniformly according to the mixing volume ratio of 10:1.

[0099] Preparation of two-component silicone sealant

[0100] Preparation of A component:

[0101] Take 100 parts of viscosity 10000 mPa·s of α, ω-dihydroxy polydimethylsiloxane and 10 parts of viscosity 400 mPa·s of dimethyl silicone oil into a kneader to stir and disperse, after 5 minutes, add 100 parts of nano active calcium carbonate with a particle size of 80 nm in the stirring process, make the glue completely cover the powder to form a self-leveling type base, control the reaction temperature to be 90℃, stir and mix for 1h, get the A component, grind and reserve.

[0102] Preparation of B component:

[0103] Put 100 parts of dimethyl silicone oil with viscosity 10000 mPa·s and 100 parts of carbon black into a planetary machine, stir under vacuum (-0.09Mpa), wait for the temperature to stabilize at 100℃, stir for 30min, get B base; cool to room temperature, then add 30 parts of propyl trimethoxysilane, 20 parts of methyl trimethoxysilane, 30 parts of γ-aminopropyl trimethoxysilane, 20 parts of γ-glycidyl ether oxygen propyl trimethoxysilane, 6 parts of polycyclic side group modified fluorosilicon crosslinking agent and 1 part of dibutyltin dilaurate, stir for 20min under nitrogen protection, get B component, seal and store.

[0104] The A component and the B component are mixed in a mixing volume ratio of 10:1 when used.

[0105] Example 3: Preparation of a two-component silicone sealant

[0106] Preparation of the A component:

[0107] Take 100 parts of α, ω-dihydroxy polydimethylsiloxane with a viscosity of 10000 mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400 mPa·s into a kneader for stirring and dispersion, and after 5 minutes, 100 parts of nano active calcium carbonate with a particle size of 80 nm are added in the stirring process to make the glue completely cover the powder to form a self-leveling base, the reaction temperature is controlled at 90°C, and stirring and mixing are carried out for 1 h to obtain the A component, which is ready for use after grinding.

[0108] Preparation of the B component:

[0109] Put 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary machine, and stir under vacuum (-0.09 Mpa) until the temperature stabilizes at 100°C for 30 min to obtain the B base; cool to room temperature, and then add 30 parts of propyl trimethoxysilane, 20 parts of methyl trimethoxysilane, 30 parts of γ-aminopropyl trimethoxysilane, 20 parts of γ-glycidyl ether propyl trimethoxysilane, 9 parts of polycyclic side group modified fluorosilicon crosslinking agent, and 1 part of dibutyltin dilaurate, and stir for 20 min under nitrogen protection to obtain the B component, which is stored in a sealed manner.

[0110] The A component and the B component are mixed in a mixing volume ratio of 10:1 when used.

[0111] Example 4: Preparation of a two-component silicone sealant

[0112] Preparation of the A component:

[0113] Take 100 parts of α, ω-dihydroxy polydimethylsiloxane with a viscosity of 20000 mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400 mPa·s into a kneader for stirring and dispersion, and after 5 minutes, 100 parts of nano active calcium carbonate with a particle size of 60 nm are added in the stirring process to make the glue completely cover the powder to form a self-leveling base, the reaction temperature is controlled at 90°C, and stirring and mixing are carried out for 1 h to obtain the A component, which is ready for use after grinding.

[0114] Preparation of the B component:

[0115] 100 parts of dimethyl silicone oil with viscosity of 10000 mPa·s and 100 parts of carbon black were added into a planetary machine, and stirred under vacuum (-0.09 Mpa). After the temperature was stabilized at 100℃ for 30 min, B base was obtained. After cooling to room temperature, 30 parts of propyl trimethoxysilane, 20 parts of methyl trimethoxysilane, 30 parts of γ-aminopropyl trimethoxysilane, 20 parts of γ-glycidyl ether oxygen propyl trimethoxysilane, 6 parts of polycyclic side group modified fluorosilicon crosslinking agent and 1 part of dibutyltin dilaurate were added, and stirred for 20 min under nitrogen protection to obtain B component, which was sealed and stored.

[0116] When used, A component and B component were mixed uniformly according to a mixing volume ratio of 10:1.

[0117] Preparation of two-component silicone sealant

[0118] Preparation of A component:

[0119] 100 parts of α, ω-dihydroxypolydimethylsiloxane with viscosity of 10000 mPa·s and 10 parts of dimethyl silicone oil with viscosity of 400 mPa·s were added into a kneader and stirred and dispersed. After 5 min, 100 parts of nano active calcium carbonate with particle size of 80 nm were added in the stirring process to make the glue completely cover the powder to form a self-leveling base. The reaction temperature was controlled at 90℃, and stirring and mixing were performed for 1 h to obtain A component, which was ground and reserved.

[0120] Preparation of B component:

[0121] 100 parts of dimethyl silicone oil with viscosity of 10000 mPa·s and 100 parts of carbon black were added into a planetary machine, and stirred under vacuum (-0.09 Mpa). After the temperature was stabilized at 100℃ for 30 min, B base was obtained. After cooling to room temperature, 30 parts of propyl trimethoxysilane, 20 parts of methyl trimethoxysilane, 30 parts of γ-aminopropyl trimethoxysilane, 20 parts of γ-glycidyl ether oxygen propyl trimethoxysilane and 1 part of dibutyltin dilaurate were added, and stirred for 20 min under nitrogen protection to obtain B component, which was sealed and stored.

[0122] When used, A component and B component were mixed uniformly according to a mixing volume ratio of 10:1.

[0123] Preparation of two-component silicone sealant

[0124] Preparation of A component:

[0125] Take 100 parts of viscosity 10000 mPa·s of α, ω-dihydroxy polydimethylsiloxane and 10 parts of viscosity 400 mPa·s of dimethyl silicone oil into a kneader to stir and disperse, after 5 minutes, add 100 parts of nano active calcium carbonate with a particle size of 80 nm in the stirring process, make the glue completely cover the powder to form a self-leveling base, control the reaction temperature to be 90℃, stir and mix for 1h, get the A component, grind and reserve.

[0126] Preparation of B component:

[0127] Put 100 parts of viscosity 10000 mPa·s of dimethyl silicone oil and 100 parts of carbon black into a planetary machine, stir under vacuum (-0.09Mpa), wait for the temperature to stabilize at 100℃, stir for 30min, get B base; cool to room temperature, then add 30 parts of propyl trimethoxysilane, 20 parts of methyl trimethoxysilane, 36 parts of γ-aminopropyl trimethoxysilane, 20 parts of γ-glycidyl ether oxypropyl trimethoxysilane and 1 part of dibutyltin dilaurate, stir for 20min under nitrogen protection, get B component, seal and store.

[0128] When used, mix A component and B component uniformly according to the mixing volume ratio of 10:1.

[0129] Preparation of two-component silicone sealant

[0130] Preparation of A component:

[0131] Take 100 parts of viscosity 10000 mPa·s of α, ω-dihydroxy polydimethylsiloxane and 10 parts of viscosity 400 mPa·s of dimethyl silicone oil into a kneader to stir and disperse, after 5 minutes, add 100 parts of nano active calcium carbonate with a particle size of 80 nm in the stirring process, make the glue completely cover the powder to form a self-leveling base, control the reaction temperature to be 90℃, stir and mix for 1h, get the A component, grind and reserve.

[0132] Preparation of B component:

[0133] Put 100 parts of viscosity 10000 mPa·s of dimethyl silicone oil and 100 parts of carbon black into a planetary machine, stir under vacuum (-0.09Mpa), wait for the temperature to stabilize at 100℃, stir for 30min, get B base; cool to room temperature, then add 30 parts of propyl trimethoxysilane, 20 parts of methyl trimethoxysilane, 36 parts of γ-aminopropyl trimethoxysilane, 20 parts of γ-glycidyl ether oxypropyl trimethoxysilane, 6 parts of α, ω-terminated hydroxyl poly methyl trifluoropropyl siloxane and 1 part of dibutyltin dilaurate, stir for 20min under nitrogen protection, get B component, seal and store.

[0134] The structure of α, ω-terminated hydroxyl poly methyl trifluoropropyl siloxane is as follows:

[0135] n is 4.

[0136] In use, the A component and the B component are mixed uniformly according to a mixing volume ratio of 10:1.

[0137] Preparation of a two-component silicone sealant

[0138] Preparation of the A component:

[0139] Take 100 parts of α, ω-dihydroxy polydimethylsiloxane with a viscosity of 10000 mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400 mPa·s into a kneader to stir and disperse, and after 5 minutes, 100 parts of nano active calcium carbonate with a particle size of 80 nm are added in the stirring process to make the glue completely cover the powder to form a self-leveling base, the reaction temperature is controlled at 90°C, and stirring is mixed for 1 h to obtain the A component, which is ready for use after grinding.

[0140] Preparation of the B component:

[0141] Put 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary machine, stir under vacuum (-0.09 Mpa), and when the temperature is stable at 100°C, stir for 30 min to obtain B base; cool to room temperature, and then add 30 parts of propyl trimethoxysilane, 20 parts of methyl trimethoxysilane, 36 parts of γ-aminopropyl trimethoxysilane, 20 parts of γ-glycidyl ether propyl trimethoxysilane, 6 parts of phenyl trimethoxysilane, and 1 part of dibutyltin dilaurate, and stir for 20 min under nitrogen protection to obtain the B component, which is sealed and stored.

[0142] In use, the A component and the B component are mixed uniformly according to a mixing volume ratio of 10:1.

[0143] Preparation of a two-component silicone sealant

[0144] Preparation of the A component:

[0145] Take 100 parts of α, ω-dihydroxy polydimethylsiloxane with a viscosity of 10000 mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400 mPa·s into a kneader to stir and disperse, and after 5 minutes, 100 parts of nano active calcium carbonate with a particle size of 80 nm are added in the stirring process to make the glue completely cover the powder to form a self-leveling base, the reaction temperature is controlled at 90°C, and stirring is mixed for 1 h to obtain the A component, which is ready for use after grinding.

[0146] Preparation of the B component:

[0147] 100 parts of dimethyl silicone oil with viscosity of 10000 mPa·s and 100 parts of carbon black were added into a planetary machine, and stirred under vacuum (-0.09 MPa). After the temperature was stabilized at 100℃ for 30 min, a B base was obtained. Then 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 36 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyl ether propyltrimethoxysilane, 6 parts of modified fluorosilicon crosslinking agent, and 1 part of dibutyltin dilaurate were added, and stirred for 20 min under nitrogen protection to obtain a B component, which was sealed and stored.

[0148] When used, the A component and the B component were mixed uniformly according to a mixing volume ratio of 10:1.

[0149] The preparation method of the modified fluorosilicon crosslinking agent is as follows:

[0150] A three-necked flask equipped with a condensation reflux device and a tetrafluoroethylene stirring paddle was connected to a nitrogen inlet and outlet, and high-purity nitrogen was introduced. 0.1 mol of α,ω-hydroxyl-terminated polymethyltrifluoropropylsiloxane, 150 mL of tetrahydrofuran, and 0.4 g of palladium-carbon catalyst were sequentially added to the flask, stirred uniformly, and heated to 60℃. Then 0.3 mol of trimethoxysilane was added, and the reaction was continued at 60℃ for 8 hours. After the reaction was completed, the temperature was lowered to room temperature, and the palladium-carbon catalyst in the mixture was removed by suction filtration through a Buchner funnel. Then the solvent in the filtered mixture was removed by rotary evaporation under vacuum at 80℃ to obtain a crude product of the modified fluorosilicon crosslinking agent. Subsequently, the crude product was heated to 130℃, and unreacted trimethoxysilane was removed by stirring under vacuum to obtain the target product, the modified fluorosilicon crosslinking agent.

[0151] The structural formula of the α,ω-hydroxyl-terminated polymethyltrifluoropropylsiloxane is as follows:

[0152] n is 4.

[0153] The differences in the raw material components in the above examples and comparative examples are shown in Table 1.

[0154] Table 1. Comparison table of differences in raw material components of examples and comparative examples

[0155]

[0156] a: 6 parts of α,ω-hydroxyl-terminated polymethyltrifluoropropylsiloxane were added in Comparative Example 3; b: 6 parts of phenyltrimethoxysilane were added in Comparative Example 4; c: 6 parts of a modified fluorosilicon crosslinking agent prepared from α,ω-hydroxyl-terminated polymethyltrifluoropropylsiloxane and trimethoxysilane were added in Comparative Example 5.

[0157] The two-component silicone sealant prepared from each of the examples and the comparative examples was mixed uniformly in a planetary mixer under vacuum at a mixing volume ratio of 10:1 between the A component and the B component, and then H-shaped test pieces were prepared and subjected to the following performance tests.

[0158] Breaking time: determined in accordance with the GB 16776-2005 standard.

[0159] Tensile adhesion at 23℃: tested in accordance with 5.9 of JG / T 475-2015.

[0160] Tensile adhesion at 80℃: tested in accordance with 5.9.2 of JG / T 475-2015 and the retention rate was calculated in accordance with 5.1.3. Tensile adhesion after water-ultraviolet light irradiation: tested in accordance with 5.9.4 of JG / T 475-2015 and the adhesive failure area was calculated in accordance with 5.1.3.

[0161] The test results are shown in Table 2.

[0162] Table 2. Performance test results of the two-component silicone sealant prepared from each of the examples and the comparative examples

[0163]

[0164] CF represents cohesive failure and AF represents adhesive failure.

[0165] As can be seen from the comparison of the data of the comparative example 1 and the examples 1-3, after the addition of the multi-benzene ring side group modified fluorosilicon crosslinking agent provided by the application, the strength, the 80℃ tensile retention rate and the adhesion after water-ultraviolet light irradiation of the two-component silicone sealant are all improved, and the improvement effect is increased with the increase of the amount of the multi-benzene ring side group modified fluorosilicon crosslinking agent.

[0166] As can be seen from the comparison of the data of the examples 1-3, with the continuous increase of the amount of the multi-benzene ring side group modified fluorosilicon crosslinking agent, the tensile strength of the prepared sealant is gradually improved, and the 80℃ tensile retention rate is also gradually improved, but when the amount is too high, the breaking time of the sealant is too long, and when the amount of the multi-benzene ring side group modified fluorosilicon crosslinking agent is 6 parts, the comprehensive performance of the sealant is best.

[0167] As can be seen from the comparison of the examples 2 and 4, the mechanical properties of the sealant are affected by the α,ω-dihydroxypolydimethylsiloxane with different viscosities and the calcium carbonate with different particle sizes, and the α,ω-dihydroxypolydimethylsiloxane with a viscosity of 20000 mPa·s and the nano active calcium carbonate with a particle size of 60 nm can further improve the mechanical properties of the sealant.

[0168] It can be known from the results of Comparative Example 2 that, without adding the multi-benzene ring side group modified fluorosilicone crosslinking agent provided by the present application, only increasing the amount of the conventional crosslinking agent cannot improve the heat resistance and water and ultraviolet light resistance of the two-component silicone sealant.

[0169] Comparative Example 3 uses unmodified α,ω-hydroxyl-terminated polymethyl trifluoropropyl siloxane to replace the multi-benzene ring side group modified fluorosilicone crosslinking agent in Example 1; Comparative Example 5 uses a modified fluorosilicone crosslinking agent prepared from α,ω-hydroxyl-terminated polymethyl trifluoropropyl siloxane and trimethoxysilane to replace the multi-benzene ring side group modified fluorosilicone crosslinking agent in Example 1; the water resistance of the obtained silicone sealant is improved compared with Comparative Example 1, but is still worse than that of Example 1, and the heat resistance cannot be improved.

[0170] Comparative Example 4 uses phenyl trimethoxysilane to replace the multi-benzene ring side group modified fluorosilicone crosslinking agent in Example 1, and the heat resistance of the obtained silicone sealant is improved compared with Comparative Example 1, but is still worse than that of Example 1, and the water resistance cannot be improved.

[0171] The technical features of the above-described examples can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above-described examples are not described, however, as long as the combinations of the technical features do not contradict each other, they should be considered as within the scope of the present disclosure.

[0172] The above-described examples only express several embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as limiting the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A modified fluorosilicone compound, characterized in that, Its structural formula is as follows: ； Where n is 4, 8 or 12.

2. A method for preparing the modified fluorosilicone compound according to claim 1, characterized in that, The process includes the following steps: Under the protection of an inert gas, α,ω-terminated hydroxyl polymethyltrifluoropropylsiloxane and dimethoxyphenylsilane undergo a dehydrogenation condensation reaction catalyzed by a palladium-on-carbon catalyst to obtain the modified fluorosilicone compound. The reaction formula is as follows: ； Where n is 4, 8 or 12.

3. The method for preparing the modified fluorosilicone compound according to claim 2, characterized in that, The molar ratio of the α,ω-terminated hydroxyl polymethyltrifluoropropylsiloxane to dimethoxyphenylsilane is 1:2~4; And / or, the ratio of the α,ω-terminated hydroxyl polymethyltrifluoropropylsiloxane to the palladium-on-carbon catalyst is 1 mol: 3 g to 5 g; And / or, the reaction is carried out in an organic solvent; And / or, the reaction temperature is 50°C to 70°C, and the time is 6 hours to 12 hours.

4. The method for preparing the modified fluorosilicone compound according to claim 3, characterized in that, The organic solvent is tetrahydrofuran.

5. The method for preparing the modified fluorosilicone compound according to claim 3, characterized in that, The reaction is carried out at a temperature of 55℃ to 65℃ for 7 to 9 hours.

6. The use of the modified fluorosilicone compound of claim 1 as a crosslinking agent in the preparation of two-component silicone sealants.

7. A two-component silicone sealant, characterized in that, Its crosslinking agent contains the modified fluorosilicone compound as described in claim 1.

8. The two-component silicone sealant according to claim 7, characterized in that, The crosslinking agent is composed of a first crosslinking agent and a second crosslinking agent. The first crosslinking agent is the modified fluorosilicone compound as described in claim 1, and the second crosslinking agent is selected from one or more combinations of tetraethyl orthosilicate, propyl orthosilicate, polyethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, polymethyltriethoxysilane oligomer, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

9. The two-component silicone sealant according to claim 8, characterized in that, The mass ratio of the first crosslinking agent to the second crosslinking agent is 2~10:15~60.

10. The two-component silicone sealant according to claim 9, characterized in that, The mass ratio of the first crosslinking agent to the second crosslinking agent is 3~9:45~55.

11. The two-component silicone sealant according to claim 10, characterized in that, The mass ratio of the first crosslinking agent to the second crosslinking agent is 4~9:48~52.

12. The two-component silicone sealant according to claim 11, characterized in that, The mass ratio of the first crosslinking agent to the second crosslinking agent is 4~7:48~52.

13. The two-component silicone sealant according to claim 12, characterized in that, The mass ratio of the first crosslinking agent to the second crosslinking agent is 5~7:

50.

14. The two-component silicone sealant according to claim 8, characterized in that, Composed of component A and component B, in parts by weight, component A is prepared from raw materials comprising the following components: 100 parts of α,ω-dihydroxypolydimethylsiloxane 60-150 parts of filler 5-25 parts of dimethyl silicone oil; Component B, by weight, is prepared from raw materials comprising the following components: 100 parts of dimethyl silicone oil 50-150 parts carbon black 2-10 parts of the first crosslinking agent 15-60 parts of the second crosslinking agent 15-60 parts of coupling agent Catalyst 0.1~1.5 parts.

15. The two-component silicone sealant according to claim 14, characterized in that, By weight, component A is prepared from raw materials comprising the following components: 100 parts of α,ω-dihydroxypolydimethylsiloxane 90-110 parts of filler 8-12 parts of dimethyl silicone oil; Component B, by weight, is prepared from raw materials comprising the following components: 100 parts of dimethyl silicone oil 90-110 parts carbon black 3-9 parts of the first crosslinking agent 45-55 parts of the second crosslinking agent 45-55 parts of coupling agent Catalyst 0.8~1.2 parts.

16. The two-component silicone sealant according to claim 15, characterized in that, The first type of crosslinking agent is 4 to 9 parts by weight.

17. The two-component silicone sealant according to claim 16, characterized in that, The first type of crosslinking agent is 4 to 7 parts by weight.

18. The two-component silicone sealant according to claim 17, characterized in that, The first type of crosslinking agent is 5 to 7 parts by weight.

19. The two-component silicone sealant according to claim 18, characterized in that, The first type of crosslinking agent has a weight of 6 parts.

20. The two-component silicone sealant according to claim 15, characterized in that, The second type of crosslinking agent is 48 to 52 parts by weight.

21. The two-component silicone sealant according to claim 15, characterized in that, The coupling agent is present in parts by weight of 48 to 52.

22. The two-component silicone sealant according to any one of claims 14-21, characterized in that, When using, the mixing volume ratio of component A and component B is 8-12:1; And / or, the viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25°C is 5000 mPa·s to 80000 mPa·s; And / or, the filler is nano-activated calcium carbonate with a particle size of 20nm~200nm; And / or, the viscosity of the dimethyl silicone oil in component A at 25°C is 300 mPa·s to 1000 mPa·s; And / or, the viscosity of the dimethyl silicone oil in component B at 25°C is 5000 mPa·s to 15000 mPa·s; And / or, the coupling agent is selected from γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, epoxycyclohexylmethyldimethoxysilane, epoxycyclohexylmethyldiethoxysilane, chloropropyltrimethoxysilane, chloropropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, and γ-aminopropylmethyldiethoxysilane. At least one of N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, anilinemethyltrimethoxysilane, anilinemethyltriethoxysilane, γ-isocyanate-propyltrimethoxysilane, glycidyltrimethoxysilane, and divinyltriaminopropyltrimethoxysilane; And / or, the catalyst is selected from at least one of dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctanoate, isopropyl titanate, and n-butyl titanate.

23. The two-component silicone sealant according to claim 22, characterized in that, The viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25°C is 1000 mPa·s to 20000 mPa·s.

24. The two-component silicone sealant according to claim 23, characterized in that, The viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25°C is 18000 mPa·s to 20000 mPa·s.

25. The two-component silicone sealant according to claim 22, characterized in that, The particle size of the filler is 60nm~85nm.

26. The two-component silicone sealant according to claim 25, characterized in that, The particle size of the filler is 78nm~82nm.

27. The two-component silicone sealant according to claim 22, characterized in that, The viscosity of dimethyl silicone oil in component A at 25°C is 350 mPa·s to 500 mPa·s.

28. The two-component silicone sealant according to claim 22, characterized in that, The viscosity of the dimethyl silicone oil in component B at 25°C is 8000 mPa·s to 12000 mPa·s.

29. A method for preparing a two-component silicone sealant according to any one of claims 14-28, characterized in that, Includes the following steps: Preparation of component A: The α,ω-dihydroxy polydimethylsiloxane, dimethyl silicone oil and filler are stirred and mixed at a temperature of 60℃~120℃ for 10min~200min to obtain component A; Preparation of component B: The dimethyl silicone oil and carbon black are vacuum stirred at 80℃~120℃ for 10min~60min, cooled to room temperature, and then the second crosslinking agent, coupling agent, first crosslinking agent and catalyst are added. The mixture is stirred under inert gas protection for 10min~200min to obtain component B.

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