Modified fluorosilicone cross-linking agent, two-component silicone sealant and preparation method of two-component silicone sealant

Abstract

The invention discloses a modified fluorosilicone cross-linking agent, a two-component silicone sealant and a preparation method of the two-component silicone sealant. The structural formula of the modified fluorosilicone cross-linking agent is shown in the specification. The modified fluorosilicone cross-linking agent is added into the two-component silicone sealant. The modified fluorosilicone compound provided by the invention is used as a cross-linking agent and is matched with conventional cross-linking agents, coupling agents and other components to prepare the two-component silicone sealant, so that the performance defects of the existing silicone sealant under long-term high-temperature and water immersion conditions are overcome, and the strength of the sealant is effectively improved; meanwhile, the high-temperature tensile retention rate of the sealant and the adhesive property after water-ultraviolet illumination are remarkably improved. # imgabs0 #

Description

Technical Field

[0001] The invention relates to the technical field of sealants, in particular to silicone sealants, and in particular to a modified fluorosilicone crosslinking agent, a two-component silicone sealant and a preparation method thereof. Background Art

[0002] Condensation type two-component room temperature vulcanized (RTV-2) silicone sealant can undergo a cross-linking reaction at room temperature to form an elastomer with a certain hardness. It has been widely used in the construction and industrial fields as the main product of sealing materials. Among them, silane cross-linking agent is an important component of sealant, which affects the curing performance and bonding performance of sealant. Its application in composite materials has been widely recognized and has a great influence on the bonding strength, water resistance and weather resistance of the substrate.

[0003] At present, the use of common two-component silicone sealants is relatively limited under certain conditions. For example, under long-term high temperature and water immersion conditions, its mechanical properties and tensile adhesion will be adversely affected. Patent CN202210877362.3 uses formula optimization to prepare a two-component high-temperature resistant and high-shear strength organic silicone adhesive, but its formula contains a large amount of organic silicone polysilazane, and the formula cost is high, which is not conducive to industrialization. Patent CN202410084455.X mixes organic siloxane / promoter dibutyltin dilaurate / cross-linking agent ethyl orthosilicate to react with each other to generate a new mixed adhesive, and then adds bamboo fiber to the mixed adhesive in a prescribed proportion, thereby improving the high temperature resistance of the two-component silicone adhesive. Patent CN202310785475.5 improves the sealant's resistance to water immersion and water UV aging by using specially treated calcium carbonate and conventional coupling agents obtained by reaction under specific conditions. Its synthesis process is relatively cumbersome and is an improvement on a single performance, and its use is limited under a variety of special conditions.

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

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

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

[0007] In the first aspect, the present invention provides a modified fluorosilicone compound, the structural formula of which is as follows:

[0008]

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

[0010] In a second aspect, the present invention provides a method for preparing the modified fluorosilicone compound, comprising the following steps: under the protection of an inert gas, α,ω-terminated hydroxyl polymethyltrifluoropropylsiloxane and dimethoxyphenylsilane undergo a dehydrogenation condensation reaction under the catalytic action of a palladium-carbon catalyst to obtain the modified fluorosilicone compound;

[0011] The reaction formula is as follows:

[0012]

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

[0014] In a third aspect, the present invention provides the use of the modified fluorosilicone compound as a crosslinking agent in the preparation of a two-component silicone sealant.

[0015] In a fourth aspect, the present invention provides a two-component silicone sealant, wherein the crosslinking agent thereof contains the modified fluorosilicone compound described in the present invention.

[0016] Preferably, the crosslinking agent is composed of a first crosslinking agent and a second crosslinking agent, wherein the first crosslinking agent is the modified fluorosilicone compound described in the present invention, and the second crosslinking agent is selected from one or more combinations of tetraethyl orthosilicate, propyl orthosilicate, polyethyl silicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, polymethyltriethoxysilane oligomer, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

[0017] Preferably, the two-component silicone sealant consists of component A and component B, and the component A is prepared from raw materials including the following components in parts by weight:

[0018] 100 parts of α,ω-dihydroxy polydimethylsiloxane

[0019] Filler 60~150 parts

[0020] 5-25 parts of dimethyl silicone oil;

[0021] The B component is prepared from the following raw materials in parts by weight:

[0022]

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

[0024] Preparation of component A: stirring and mixing the α,ω-dihydroxy polydimethylsiloxane, dimethyl silicone oil and filler at a temperature of 60° C. to 120° C. for 10 min to 200 min to obtain component A;

[0025] Preparation of component B: vacuum-stir the dimethyl silicone oil and carbon black at a temperature of 80°C to 120°C for 10 to 60 minutes, cool to room temperature, add the second cross-linking agent, coupling agent, first cross-linking agent and catalyst, and stir under inert gas protection for 10 to 200 minutes to obtain component B.

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

[0027] Aiming at the problem that traditional two-component silicone sealants have performance degradation at high temperatures and poor water immersion performance, the present invention prepares a modified fluorosilicone compound with multiple benzene ring side groups by dehydrogenation condensation of dimethoxyphenylsilane and low molecular weight α, ω-terminated hydroxyl polymethyltrifluoropropylsiloxane under the catalysis of palladium-carbon catalyst. The compound can be added to the two-component silicone sealant as a cross-linking agent, and can simultaneously improve the heat resistance and water immersion adhesion of the two-component silicone sealant.

[0028] The two-component silicone sealant prepared by using the modified fluorosilicone compound provided by the present invention as a cross-linking agent in combination with conventional cross-linking agents, coupling agents and other components solves the performance defects of existing silicone sealants under long-term high temperature and water immersion conditions, effectively improves the strength of the sealant, and at the same time, the high-temperature tensile retention rate of the sealant and the bonding performance after water-ultraviolet irradiation are significantly improved.

[0029] The modified fluorosilicon compound of the invention has a simple synthesis process, a high product yield, recoverable catalysts and solvents, a simple post-treatment process, and is suitable for industrial production. DETAILED DESCRIPTION

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

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

[0032] The terms "including" and "having" and any variations thereof of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, device, product or equipment comprising a series of steps is not limited to the listed steps or modules, but may optionally include steps not listed, or may optionally include other steps inherent to these processes, methods, products or equipment.

[0033] In the present invention, the term "multiple" refers to two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0034] Some embodiments of the present invention relate to a modified fluorosilicone compound, the structural formula of which is as follows:

[0035]

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

[0037] Some embodiments of the present invention relate to a method for preparing a modified fluorosilicone compound, comprising the following steps: under the protection of an inert gas, α,ω-terminated hydroxyl polymethyltrifluoropropylsiloxane and dimethoxyphenylsilane undergo a dehydrogenation condensation reaction under the catalytic action of a palladium-carbon catalyst to obtain the modified fluorosilicone 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 polymethyltrifluoropropylsiloxane to dimethoxyphenylsilane is 1:2-4.

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

[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 reaction temperature is 50° C. to 70° C., and the reaction time is 6 hours to 12 hours.

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

[0046] Some embodiments of the present invention involve the use of the modified fluorosilicone compound as a crosslinking agent in the preparation of a two-component silicone sealant.

[0047] Some embodiments of the present invention relate to a two-component silicone sealant, the crosslinking agent of which contains the modified fluorosilicone compound described in the present invention.

[0048] In some embodiments, the crosslinker is composed of a first crosslinker and a second crosslinker, wherein the first crosslinker is the modified fluorosilicone compound described in the present invention, and the second crosslinker is selected from one or more combinations of tetraethyl orthosilicate, propyl orthosilicate, polyethyl silicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, polymethyltriethoxysilane oligomer, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

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

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

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

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

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

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

[0055] 100 parts of α,ω-dihydroxy polydimethylsiloxane

[0056] Filler 60~150 parts

[0057] 5-25 parts of dimethyl silicone oil;

[0058] The B component is prepared from the following raw materials in parts by weight:

[0059]

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

[0061] 100 parts of α,ω-dihydroxy polydimethylsiloxane

[0062] Filler 90~110 parts

[0063] 8-12 parts of dimethyl silicone oil;

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

[0065]

[0066] In some embodiments, the weight portion of the first cross-linking agent is 4 to 9 parts.

[0067] In some embodiments, the weight portion of the first cross-linking agent is 4 to 7 parts.

[0068] In some embodiments, the weight portion of the first cross-linking agent is 5 to 7 parts.

[0069] In some embodiments, the weight portion of the first cross-linking agent is 6 parts.

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

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

[0072] In some embodiments, the mixing volume ratio of component A to component B is 8 to 12:1 during use.

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

[0074] In some embodiments, the filler is nano-activated calcium carbonate, and its particle size is 20nm to 200nm, preferably 60nm to 85nm, and more preferably 78nm to 82nm.

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

[0076] In some embodiments, the viscosity of the dimethyl silicone oil in component B at 25° C. is 5000 mPa·s to 15000 mPa·s, preferably 8000 mPa·s to 12000 mPa·s.

[0077] In some embodiments, the coupling agent is selected from γ-glycidyloxypropyl trimethoxysilane, γ-glycidyloxypropyl triethoxysilane, epoxycyclohexylmethyl dimethoxysilane, epoxycyclohexylmethyl diethoxysilane, chloropropyl trimethoxysilane, chloropropyl triethoxysilane, γ-(2,3-epoxypropoxy)propyl trimethoxysilane, γ-aminopropyl trimethoxysilane, γ-aminopropyl triethoxysilane, γ-aminopropyl methyl dimethoxysilane, γ-aminopropyl methyl diethoxysilane, At least one of silane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, anilinomethyltrimethoxysilane, anilinomethyltriethoxysilane, γ-isocyanatepropyltrimethoxysilane, epoxypropyltrimethoxysilane, and divinyltriaminopropyltrimethoxysilane.

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

[0079] Some embodiments of the present invention relate to a method for preparing the two-component silicone sealant, comprising the following steps:

[0080] Preparation of component A: stirring and mixing the α,ω-dihydroxy polydimethylsiloxane, dimethyl silicone oil and nano-activated calcium carbonate at a temperature of 60° C. to 120° C. for 10 min to 200 min to obtain component A;

[0081] Preparation of component B: vacuum stir the dimethyl silicone oil and carbon black at a temperature of 80°C to 120°C for 10min to 60min, then add the second crosslinking agent, coupling agent, first crosslinking agent and catalyst, and stir under inert gas protection for 10min to 200min to obtain component B.

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

[0083] Preparation of component A: stirring and mixing the α,ω-dihydroxy polydimethylsiloxane, dimethyl silicone oil and filler at a temperature of 80° C. to 100° C. for 40 min to 90 min to obtain component A;

[0084] Preparation of component B: vacuum stir the dimethyl silicone oil and carbon black at a temperature of 90°C to 110°C for 20min to 40min, cool to room temperature, add the second crosslinking agent, coupling agent, first crosslinking agent and catalyst, and stir under inert gas protection for 10min to 30min to obtain component B.

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

[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 parts by weight unless otherwise specified, and the room temperature range refers to 15°C to 30°C.

[0088] The preparation method of the polyphenyl ring side group modified fluorosilicone crosslinking agent in the following embodiments is as follows:

[0089] Connect a three-necked flask equipped with a condensation reflux device and a tetrafluoroethylene stirring paddle to the nitrogen inlet and outlet, and pass high-purity nitrogen. Add 0.1 mol of α, ω-terminated hydroxyl polymethyl trifluoropropyl siloxane, 150 mL of tetrahydrofuran, and 0.4 g of palladium carbon catalyst to the flask in turn, stir evenly and heat to 60°C, then add 0.3 mol of dimethoxyphenylsilane, continue heating and reacting at 60°C for 8 hours, cool to room temperature after the reaction is completed, and remove the palladium carbon catalyst in the mixed solution by suction filtration through a Buchner funnel. Then remove the solvent from the filtered mixed solution under vacuum conditions at 80°C using a rotary evaporator to obtain a crude product of a polyphenyl ring side group modified fluorosilicone crosslinker. Subsequently, the obtained crude product is heated to 130°C, stirred and vacuumed to remove unreacted dimethoxyphenylsilane, and the resulting liquid is the target product, a polyphenyl ring side group modified fluorosilicone crosslinker, with a yield of 93%. The reaction formula is as follows:

[0090]

[0091] Among them, n is 4.

[0092] Infrared data characterization of the product: No 3710cm -1 The stretching vibration peak of silanol at 2850 cm-1 indicates that the dehydrogenation reaction between silanol and silanol is complete. -1 1094cm -1 The characteristic peak of Si-OCH3 was found at , proving that the target product was successfully synthesized.

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

[0094] Preparation of component A:

[0095] Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400mPa·s, add them into a kneader and stir and disperse them. After 5 minutes, add 100 parts of nano-activated calcium carbonate with a particle size of 80nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C, stir and mix for 1 hour to obtain component A, and grind it for use.

[0096] Preparation of component B:

[0097] Add 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary mill, stir under vacuum (-0.09 MPa), and stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B; cool to room temperature, add 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 30 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane, 3 parts of polyphenyl ring side group modified fluorosilicone crosslinking agent and 1 part of dibutyltin dilaurate, stir for 20 minutes under nitrogen protection to obtain component B, and seal for storage.

[0098] When using, mix component A and component B evenly in a mixing volume ratio of 10:1.

[0099] Example 2: Preparation of two-component silicone sealant

[0100] Preparation of component A:

[0101] Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400mPa·s, add them into a kneader and stir and disperse them. After 5 minutes, add 100 parts of nano-activated calcium carbonate with a particle size of 80nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C, stir and mix for 1 hour to obtain component A, and grind it for use.

[0102] Preparation of component B:

[0103] Add 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary mill, stir under vacuum (-0.09 MPa), and stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B; cool to room temperature, add 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 30 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane, 6 parts of polyphenyl ring side group modified fluorosilicone crosslinking agent and 1 part of dibutyltin dilaurate, stir for 20 minutes under nitrogen protection to obtain component B, and seal for storage.

[0104] When using, mix component A and component B evenly in a mixing volume ratio of 10:1.

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

[0106] Preparation of component A:

[0107] Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400mPa·s, add them into a kneader and stir and disperse them. After 5 minutes, add 100 parts of nano-activated calcium carbonate with a particle size of 80nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C, stir and mix for 1 hour to obtain component A, and grind it for use.

[0108] Preparation of component B:

[0109] Add 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary mill, stir under vacuum (-0.09 MPa), and stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B; cool to room temperature, add 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 30 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane, 9 parts of polyphenyl ring side group modified fluorosilicone crosslinking agent and 1 part of dibutyltin dilaurate, stir for 20 minutes under nitrogen protection to obtain component B, and seal for storage.

[0110] When using, mix component A and component B evenly in a mixing volume ratio of 10:1.

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

[0112] Preparation of component A:

[0113] Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 20000mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400mPa·s, add them into a kneader and stir and disperse them. After 5 minutes, add 100 parts of nano-activated calcium carbonate with a particle size of 60nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C, stir and mix for 1 hour to obtain component A, and grind it for use.

[0114] Preparation of component B:

[0115] Add 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary mill, stir under vacuum (-0.09 MPa), and stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B; cool to room temperature, add 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 30 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane, 6 parts of polyphenyl ring side group modified fluorosilicone crosslinking agent and 1 part of dibutyltin dilaurate, stir for 20 minutes under nitrogen protection to obtain component B, and seal for storage.

[0116] When using, mix component A and component B evenly in a mixing volume ratio of 10:1.

[0117] Comparative Example 1: Preparation of two-component silicone sealant

[0118] Preparation of component A:

[0119] Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400mPa·s, add them into a kneader and stir and disperse them. After 5 minutes, add 100 parts of nano-activated calcium carbonate with a particle size of 80nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C, stir and mix for 1 hour to obtain component A, and grind it for use.

[0120] Preparation of component B:

[0121] Add 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary mill, stir under vacuum (-0.09 MPa), and stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B; cool to room temperature, add 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 30 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane and 1 part of dibutyltin dilaurate, stir for 20 minutes under nitrogen protection to obtain component B, and seal for storage.

[0122] When using, mix component A and component B evenly in a mixing volume ratio of 10:1.

[0123] Comparative Example 2: Preparation of two-component silicone sealant

[0124] Preparation of component A:

[0125] Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400mPa·s, add them into a kneader and stir and disperse them. After 5 minutes, add 100 parts of nano-activated calcium carbonate with a particle size of 80nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C, stir and mix for 1 hour to obtain component A, and grind it for use.

[0126] Preparation of component B:

[0127] Add 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary mill, stir under vacuum (-0.09 MPa), and stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B; cool to room temperature, add 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 36 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane and 1 part of dibutyltin dilaurate, stir for 20 minutes under nitrogen protection to obtain component B, and seal for storage.

[0128] When using, mix component A and component B evenly in a mixing volume ratio of 10:1.

[0129] Comparative Example 3: Preparation of two-component silicone sealant

[0130] Preparation of component A:

[0131] Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400mPa·s, add them into a kneader and stir and disperse them. After 5 minutes, add 100 parts of nano-activated calcium carbonate with a particle size of 80nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C, stir and mix for 1 hour to obtain component A, and grind it for use.

[0132] Preparation of component B:

[0133] 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black were added to a planetary mill, and stirred under vacuum (-0.09 MPa). After the temperature stabilized at 100°C, the mixture was stirred for 30 min to obtain base material B. The mixture was cooled to room temperature, and 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 36 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane, 6 parts of α, ω-terminated hydroxyl polymethyltrifluoropropylsiloxane and 1 part of dibutyltin dilaurate were added. The mixture was stirred for 20 min under nitrogen protection to obtain component B, which was then sealed and stored.

[0134] Among them, the structural formula of α,ω-terminated hydroxyl polymethyl trifluoropropyl siloxane is as follows:

[0135] n is 4.

[0136] When using, mix component A and component B evenly in a mixing volume ratio of 10:1.

[0137] Comparative Example 4: Preparation of two-component silicone sealant

[0138] Preparation of component A:

[0139] Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400mPa·s, add them into a kneader and stir and disperse them. After 5 minutes, add 100 parts of nano-activated calcium carbonate with a particle size of 80nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C, stir and mix for 1 hour to obtain component A, and grind it for use.

[0140] Preparation of component B:

[0141] Add 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary mill, stir under vacuum (-0.09 MPa), and stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B; cool to room temperature, add 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 36 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane, 6 parts of phenyltrimethoxysilane and 1 part of dibutyltin dilaurate, stir for 20 minutes under nitrogen protection to obtain component B, and seal for storage.

[0142] When using, mix component A and component B evenly in a mixing volume ratio of 10:1.

[0143] Comparative Example 5: Preparation of two-component silicone sealant

[0144] Preparation of component A:

[0145] Take 100 parts of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 10000mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400mPa·s, add them into a kneader and stir and disperse them. After 5 minutes, add 100 parts of nano-activated calcium carbonate with a particle size of 80nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C, stir and mix for 1 hour to obtain component A, and grind it for use.

[0146] Preparation of component B:

[0147] Add 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black into a planetary mill, stir under vacuum (-0.09 MPa), and stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B. Then add 30 parts of propyltrimethoxysilane, 20 parts of methyltrimethoxysilane, 36 parts of γ-aminopropyltrimethoxysilane, 20 parts of γ-glycidyloxypropyltrimethoxysilane, 6 parts of modified fluorosilicone crosslinking agent and 1 part of dibutyltin dilaurate, stir for 20 minutes under nitrogen protection to obtain component B, and seal for storage.

[0148] When using, mix component A and component B evenly in a mixing volume ratio of 10:1.

[0149] Wherein, the preparation method of the modified fluorosilicone crosslinking agent is as follows:

[0150] Connect a three-necked flask equipped with a condensing reflux device and a tetrafluoroethylene stirring paddle to the nitrogen inlet and outlet, and introduce high-purity nitrogen. Add 0.1 mol of α, ω-terminated hydroxyl polymethyl trifluoropropyl siloxane, 150 mL of tetrahydrofuran, and 0.4 g of palladium carbon catalyst to the flask in sequence, stir evenly and heat to 60°C, then add 0.3 mol of trimethoxysilane, continue heating and reacting at 60°C for 8 hours, cool to room temperature after the reaction is completed, and remove the palladium carbon catalyst in the mixed solution by suction filtration through a Buchner funnel. Then remove the solvent from the filtered mixed solution under vacuum conditions at 80°C using a rotary evaporator to obtain a crude modified fluorosilicone crosslinker. Subsequently, the crude product is heated to 130°C, stirred and vacuumed to remove unreacted trimethoxysilane, and the resulting liquid is the target product, the modified fluorosilicone crosslinker.

[0151] Among them, the structural formula of α,ω-terminated hydroxyl polymethyl trifluoropropyl siloxane 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 of raw material components between examples and comparative examples

[0155]

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

[0157] Take the two-component silicone sealant prepared in each embodiment and comparative example, mix component A and component B in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1, and then make an H-type test piece to perform the following performance test:

[0158] Breaking time: measured in accordance with GB16776-2005 standard.

[0159] 23℃ tensile adhesion: tested according to 5.9 of JG / T 475-2015.

[0160] 80℃ tensile adhesion: Tested according to 5.9.2 of JG / T 475-2015 and the retention rate calculated according to 5.1.3. Tensile adhesion after water-ultraviolet irradiation: Tested according to 5.9.4 of JG / T 475-2015 and the bonding failure area calculated according to 5.1.3.

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

[0162] Table 2. Performance test results of two-component silicone sealants prepared in Examples and Comparative Examples

[0163]

[0164] *CF stands for cohesive failure and AF stands for adhesive failure.

[0165] From the comparison of the data of Comparative Example 1 and Examples 1-3, it can be seen that after adding the polybenzene ring side group modified fluorosilicone crosslinking agent provided by the present invention, the strength, 80°C tensile retention rate, and adhesion after water-ultraviolet irradiation of the two-component silicone sealant are improved, and the improvement effect is enhanced with the increase of the amount of polybenzene ring side group modified fluorosilicone crosslinking agent added.

[0166] From the data comparison of Examples 1-3, it can be seen that with the continuous increase in the amount of polyphenyl ring side-group modified fluorosilicone crosslinking agent, the tensile strength of the prepared sealant gradually increases, and its 80°C tensile retention rate also gradually increases. However, when the amount is too high, the tearing time of the sealant will be too long. When the addition amount of polyphenyl ring side-group modified fluorosilicone crosslinking agent is 6 parts, the comprehensive performance of the sealant is best.

[0167] By comparing Examples 2 and 4, it can be obtained that α,ω-dihydroxypolydimethylsiloxane with different viscosities and calcium carbonate with different particle sizes will affect the mechanical properties of the sealant. α,ω-dihydroxypolydimethylsiloxane with a viscosity of 20000 mPa·s combined with nano-activated calcium carbonate with a particle size of 60 nm can further improve the mechanical properties of the sealant.

[0168] It can be seen from the results of Comparative Example 2 that without adding the polyphenyl ring side group modified fluorosilicone crosslinking agent provided by the present invention, the heat resistance and water resistance to ultraviolet light of the two-component silicone sealant cannot be improved by simply increasing the amount of the conventional crosslinking agent.

[0169] In Comparative Example 3, the polyphenyl ring side group modified fluorosilicone crosslinking agent in Example 1 is replaced with unmodified α, ω-terminal hydroxyl polymethyltrifluoropropylsiloxane; in Comparative Example 5, the polyphenyl ring side group modified fluorosilicone crosslinking agent in Example 1 is replaced with a modified fluorosilicone crosslinking agent prepared from α, ω-terminal hydroxyl polymethyltrifluoropropylsiloxane and trimethoxysilane; the water resistance of the resulting silicone sealant is improved compared with that in Comparative Example 1, but is still worse than that in Example 1, and the heat resistance cannot be improved.

[0170] Comparative Example 4 replaces the polyphenyl ring side group modified fluorosilicone crosslinking agent in Example 1 with phenyltrimethoxysilane. The heat resistance of the obtained silicone sealant is improved compared with Comparative Example 1, but it is still worse than Example 1 and cannot improve the water resistance.

[0171] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0172] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A modified fluorine silicon compound, characterized in that: Its structural formula is as follows: Wherein, n is 4, 8 or 12.

2. A method for preparing the modified fluorosilicone compound according to claim 1, characterized in that: The method comprises the following steps: under the protection of an inert gas, α,ω-terminated hydroxyl polymethyl trifluoropropyl siloxane and dimethoxyphenyl silane undergo a dehydrogenation condensation reaction under the catalytic action of a palladium carbon catalyst to obtain the modified fluorosilicon compound; The reaction formula is as follows: Wherein, n is 4, 8 or 12.

3. The method for preparing the modified fluorine silicon 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 carbon catalyst is 1 mol: 3 g to 5 g; And / or, the reaction is carried out in an organic solvent, and the organic solvent is preferably tetrahydrofuran; And / or, the reaction temperature is 50°C to 70°C, and the reaction time is 6 hours to 12 hours; Preferably, the reaction temperature is 55° C. to 65° C., and the reaction time is 7 hours to 9 hours.

4. Use of the modified fluorosilicone compound according to claim 1 as a crosslinking agent in the preparation of a two-component silicone sealant.

5. A two-component silicone sealant, characterized in that: The crosslinking agent contains the modified fluorosilicone compound according to claim 1.

6. The two-component silicone sealant according to claim 5, characterized in that: The crosslinking agent is composed of a first crosslinking agent and a second crosslinking agent, wherein the first crosslinking agent is the modified fluorosilicone compound according to claim 1, and the second crosslinking agent is selected from one or more combinations of ethyl orthosilicate, propyl orthosilicate, polyethyl silicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, polymethyltriethoxysilane oligomer, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane; Preferably, the mass ratio of the first crosslinking agent to the second crosslinking agent is 2-10:15-60, preferably 3-9:45-55, preferably 4-9:48-52, preferably 4-7:48-52, preferably 5-7:

50.

7. The two-component silicone sealant according to claim 6, characterized in that: The invention is composed of component A and component B, wherein the component A is prepared from raw materials including the following components in parts by weight: 100 parts of α,ω-dihydroxy polydimethylsiloxane Filler 60~150 parts 5-25 parts of dimethyl silicone oil; In parts by weight, the B component is prepared from raw materials including the following components:

8. The two-component silicone sealant according to claim 7, characterized in that: The component A is prepared from the following raw materials in parts by weight: 100 parts of α,ω-dihydroxy polydimethylsiloxane Filler 90~110 parts 8-12 parts of dimethyl silicone oil; The B component is prepared from the following raw materials in parts by weight: Preferably, the weight portion of the first cross-linking agent is 4 to 9 parts, preferably 4 to 7 parts, more preferably 5 to 7 parts, more preferably 6 parts; Preferably, the weight portion of the second cross-linking agent is 48 to 52 parts; Preferably, the weight portion of the coupling agent is 48 to 52 parts.

9. The two-component silicone sealant according to claim 7 or 8, characterized in that: When used, the mixing volume ratio of component A to component B is 8-12:1; and / or, the viscosity of the α,ω-dihydroxy polydimethylsiloxane at 25° C. is 5000 mPa·s to 80000 mPa·s, preferably 1000 mPa·s to 20000 mPa·s, and more preferably 18000 mPa·s to 20000 mPa·s; And / or, the filler is nano-active calcium carbonate, and its particle size is 20nm to 200nm, preferably 60nm to 85nm, and more preferably 78nm to 82nm; and / or the viscosity of the dimethyl silicone oil in component A at 25° C. is 300 mPa·s to 1000 mPa·s, preferably 350 mPa·s to 500 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, preferably 8000 mPa·s to 12000 mPa·s; And / or, the coupling agent is selected from γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, epoxycyclohexylmethyldimethoxysilane, epoxycyclohexylmethyldiethoxysilane, chloropropyltrimethoxysilane, chloropropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, 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, anilinomethyltrimethoxysilane, anilinomethyltriethoxysilane, γ-isocyanatepropyltrimethoxysilane, epoxypropyltrimethoxysilane, and divinyltriaminopropyltrimethoxysilane; And / or, the catalyst is at least one selected from dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate, isopropyl titanate and n-butyl titanate.

10. A method for preparing a two-component silicone sealant according to any one of claims 7 to 9, characterized in that: The steps include: Preparation of component A: stirring and mixing the α,ω-dihydroxy polydimethylsiloxane, dimethyl silicone oil and filler at a temperature of 60° C. to 120° C. for 10 min to 200 min to obtain component A; Preparation of component B: vacuum-stir the dimethyl silicone oil and carbon black at a temperature of 80°C to 120°C for 10 to 60 minutes, cool to room temperature, add the second cross-linking agent, coupling agent, first cross-linking agent and catalyst, and stir under inert gas protection for 10 to 200 minutes to obtain component B.

Images