Modified fluorosilicone polymer, two-component silicone sealant and preparation method of two-component silicone sealant

Abstract

The invention discloses a modified fluorosilicone polymer, a two-component silicone sealant and a preparation method of the two-component silicone sealant. The structural formula of the modified fluorosilicone polymer is shown in the specification. The preparation raw materials of the two-component silicone sealant contain the modified fluorosilicone polymer. The modified fluorosilicone polymer provided by the invention is used as a basic polymer to replace conventional simethicone, and is matched with alpha, omega-dihydroxy polydimethylsiloxane, a cross-linking agent, a coupling agent and other components to prepare a two-component silicone sealant which has relatively high normal-temperature and low-temperature strength and also has very good heat resistance and water resistance; the defect that the performance of an existing silicone sealant is reduced under the conditions of high temperature and water immersion is overcome. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of sealants, in particular to silicone sealants, and in particular to a modified fluorosilicone polymer, 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. The waterproof sealing quality of traditional two-component silicone sealants is one of the key factors limiting their service life and stability. In addition, due to the influence of some special environments and construction conditions that are exposed to heat and humidity for a long time, the sealant must have excellent high and low temperature applicability, water resistance and thermal aging stability to meet the requirements of use under specific conditions.

[0003] Therefore, it is necessary to improve the high and low temperature performance and water resistance of two-component silicone sealants to expand the application of two-component silicone sealants under more stringent conditions.

[0004] Patent CN111748315A prepares a high-bonding and water-boiling-resistant silicone insulating sealant, which mainly improves the heat resistance and water-boiling resistance of the sealant by synthesizing a viscosity-enhancing promoter and a heat-resistant agent and then combining them with the production formula of a conventional sealant. This scheme requires the synthesis of two new materials, and the synthesis route is relatively complicated, which is not conducive to actual production. Summary of the invention

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

[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 polymer, the structural formula of which is as follows:

[0008]

[0009] Among them, n is selected from an integer between 16 and 150, preferably an integer between 30 and 80, more preferably an integer between 40 and 70, more preferably an integer between 50 and 60, and more preferably 53, 54, 55 or 56.

[0010] In a second aspect, the present invention provides a method for preparing the modified fluorosilicone polymer, 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 polymer;

[0011] The reaction formula is as follows:

[0012]

[0013] Among them, n is selected from an integer between 16 and 150, preferably an integer between 30 and 80, more preferably an integer between 40 and 70, more preferably an integer between 50 and 60, and more preferably 53, 54, 55 or 56.

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

[0015] In a fourth aspect, the present invention provides a two-component silicone sealant, the raw materials for preparing the two-component silicone sealant contain the modified fluorosilicone polymer described in the present invention.

[0016] 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:

[0017] 100 parts of α,ω-dihydroxy polydimethylsiloxane

[0018] Filler 60~150 parts

[0019] 5-25 parts of dimethyl silicone oil;

[0020] In parts by weight, the B component is prepared from raw materials including the following components:

[0021]

[0022] The base material consists of 50 to 250 parts of the modified fluorosilicone polymer and 50 to 150 parts of carbon black.

[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 stirring the modified fluorosilicone polymer and carbon black at a temperature of 70°C to 140°C for 10min to 60min to obtain a base material; after cooling to room temperature, adding the crosslinking agent, coupling agent and catalyst to the base material, stirring for 10min to 100min under inert gas protection 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 poor high and low temperature performance and water resistance, the present invention prepares a modified fluorosilicone polymer with multiple benzene ring side groups by dehydrogenation condensation of dimethoxyphenylsilane and α, ω-terminated hydroxyl polymethyltrifluoropropylsiloxane with a certain molecular weight under the catalytic action of a palladium-carbon catalyst, and then uses the modified fluorosilicone polymer as a base polymer to prepare a two-component silicone sealant, which can simultaneously improve the high and low temperature bonding strength, heat resistance and water resistance of the obtained two-component silicone sealant.

[0028] The two-component silicone sealant prepared by using the modified fluorosilicone polymer provided by the present invention as a base polymer to replace conventional dimethyl silicone oil and in combination with α,ω-dihydroxypolydimethylsiloxane, a crosslinking agent, a coupling agent and other components has high room temperature and low temperature strength, and also has good heat resistance and water resistance, thereby solving the defect of existing silicone sealants that their performance deteriorates under high temperature and water immersion conditions.

[0029] The modified fluorosilicone polymer 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 polymer, the structural formula of which is as follows:

[0035]

[0036] Among them, n is selected from an integer between 16 and 150, preferably an integer between 30 and 80, more preferably an integer between 40 and 70, more preferably an integer between 50 and 60, and more preferably 53, 54, 55 or 56.

[0037] Some embodiments of the present invention relate to a method for preparing a modified fluorosilicone polymer, 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 polymer;

[0038] The reaction formula is as follows:

[0039]

[0040] Among them, n is selected from an integer between 16 and 150, preferably an integer between 30 and 80, more preferably an integer between 40 and 70, more preferably an integer between 50 and 60, and more preferably 53, 54, 55 or 56.

[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 polymer as a base polymer in the preparation of a two-component silicone sealant.

[0047] Some embodiments of the present invention relate to a two-component silicone sealant, the raw materials for preparing the two-component silicone sealant contain the modified fluorosilicone polymer described in the present invention.

[0048] 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:

[0049] 100 parts of α,ω-dihydroxy polydimethylsiloxane

[0050] Filler 60~150 parts

[0051] 5-25 parts of dimethyl silicone oil;

[0052] In parts by weight, the B component is prepared from raw materials including the following components:

[0053]

[0054] The base material consists of 50 to 250 parts of the modified fluorosilicone polymer and 50 to 150 parts of carbon black.

[0055] In some embodiments, the component A is prepared from raw materials including the following components in parts by weight:

[0056] 100 parts of α,ω-dihydroxy polydimethylsiloxane

[0057] Filler 90~110 parts

[0058] 8-12 parts of dimethyl silicone oil;

[0059] In parts by weight, the B component is prepared from raw materials including the following components:

[0060]

[0061] The base material consists of 80 to 220 parts of the modified fluorosilicone polymer and 90 to 110 parts of carbon black.

[0062] In some embodiments, the weight proportion of the modified fluorosilicone polymer is 100 to 200 parts, more preferably 140 to 160 parts.

[0063] In some embodiments, the weight portion of the cross-linking agent is 48 to 52 parts.

[0064] In some embodiments, the weight portion of the coupling agent is 48 to 52 parts.

[0065] In some embodiments, the water content of the base material is less than 1400 ppm.

[0066] In some embodiments, the water content of the base material is less than 500 ppm.

[0067] In some embodiments, the water content of the base material is 400 ppm to 460 ppm.

[0068] In some embodiments, the mixing volume ratio of component A to component B is 8 to 12:1 during use.

[0069] 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 30000 mPa·s, and more preferably 18000 mPa·s to 20000 mPa·s.

[0070] In some embodiments, the filler is nano-activated calcium carbonate, and its particle size is 20nm to 200nm, preferably 60nm to 150nm, and more preferably 80nm to 120nm.

[0071] In some embodiments, the viscosity of the dimethyl silicone oil at 25° C. is 300 mPa·s to 1000 mPa·s, preferably 350 mPa·s to 500 mPa·s.

[0072] In some embodiments, the crosslinking agent is selected from at least one of tetraethyl orthosilicate, propyl orthosilicate, polyethyl silicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, polymethyltriethoxysilane oligomer, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

[0073] 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.

[0074] 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.

[0075] Some embodiments of the present invention relate to a method for preparing the two-component silicone sealant, comprising the following steps:

[0076] 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;

[0077] Preparation of component B: vacuum stirring the modified fluorosilicone polymer and carbon black at a temperature of 70°C to 140°C for 10min to 60min to obtain a base material; after cooling to room temperature, adding the crosslinking agent, coupling agent and catalyst to the base material, stirring for 10min to 100min under inert gas protection to obtain component B.

[0078] In some embodiments, the method for preparing the two-component silicone sealant comprises the following steps:

[0079] 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;

[0080] Preparation of component B: vacuum stirring the modified fluorosilicone polymer and carbon black at a temperature of 80°C to 120°C for 20min to 40min to obtain a base material; after cooling to room temperature, adding the crosslinking agent, coupling agent and catalyst to the base material, stirring for 10min to 20min under the protection of inert gas to obtain component B.

[0081] In some of the embodiments, the modified fluorosilicone polymer and carbon black are stirred under vacuum at a temperature of 90° C. to 110° C. for 25 min to 35 min.

[0082] In some embodiments, the vacuum degree of the vacuum stirring is -0.08Mpa to -0.095Mpa.

[0083] The following are specific embodiments.

[0084] 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.

[0085] The preparation methods of the modified fluorosilicone polymers in the following Examples 1-4 are as follows:

[0086] Connect a three-necked flask equipped with a condensing reflux device and a tetrafluoroethylene stirring paddle to the nitrogen inlet and outlet, and pass high-purity nitrogen. Add 1 mol of α, ω-terminated hydroxyl polymethyl trifluoropropyl siloxane, 1.5L of tetrahydrofuran, and 4g of palladium carbon catalyst to the flask in turn, stir evenly and heat to 60°C, then add 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 modified fluorosilicone polymer. Subsequently, the crude product was heated to 130°C, stirred and vacuumed to remove unreacted dimethoxyphenylsilane, and the resulting oily liquid was the target product, the modified fluorosilicone polymer, with a yield of 94%. The reaction formula is as follows:

[0087]

[0088] Among them, n is 54.

[0089] Infrared data characterization of the product: No 3710cm -1 The stretching vibration peak of silanol at 2850 cm-1 proves 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.

[0090] Embodiment 1:

[0091] The preparation method of the two-component silicone sealant provided in this embodiment is as follows:

[0092] Preparation of component A:

[0093] Take 100 parts of terminal hydroxyl-terminated polydimethylsiloxane 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 100nm during stirring to make the glue completely cover the powder to form a self-leveling base material. Control the reaction temperature to 90°C and stir and mix for 1 hour. Base material A (i.e. component A) is ground and set aside.

[0094] Preparation of component B:

[0095] Add 100 parts of modified fluorosilicone polymer and 100 parts of carbon black into a planetary mixer and stir under vacuum (-0.09 MPa). Stir for 30 minutes until the temperature stabilizes at 70°C. ，Obtain base material B, and after the base material is cooled to room temperature, add 50 parts of methyltrimethoxysilane, 25 parts of γ-aminopropyltrimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.8 parts of dibutyltin dilaurate, and stir for 10 minutes under nitrogen protection. The material temperature must be lower than 50°C to obtain component B, which is sealed and stored.

[0096] When in use, mix component A and component B evenly in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1.

[0097] Embodiment 2:

[0098] The preparation method of the two-component silicone sealant provided in this embodiment is as follows:

[0099] Preparation of component A:

[0100] Take 100 parts of end-hydroxyl-terminated polydimethylsiloxane 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 100nm 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 base material A (i.e. component A), and grind it for use.

[0101] Preparation of component B:

[0102] Add 100 parts of modified fluorosilicone polymer and 100 parts of carbon black into a planetary mixer and stir under vacuum (-0.09MPa). Stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B. After the base material is cooled to room temperature, add 50 parts of methyltrimethoxysilane, 25 parts of γ-aminopropyltrimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.8 parts of dibutyltin dilaurate. Stir for 10 minutes under nitrogen protection. The material temperature must be lower than 50°C to obtain component B, which is then sealed and stored.

[0103] When in use, mix component A and component B evenly in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1.

[0104] Embodiment 3:

[0105] The preparation method of the two-component silicone sealant provided in this embodiment is as follows:

[0106] Preparation of component A:

[0107] Take 100 parts of end-hydroxyl-terminated polydimethylsiloxane 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 100nm 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 base material A (i.e. component A), and grind it for use.

[0108] Preparation of component B:

[0109] Add 150 modified fluorosilicone polymer and 100 parts of carbon black into a planetary mixer and stir under vacuum (-0.09MPa). Stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B. After the base material is cooled to room temperature, add 50 parts of methyltrimethoxysilane, 25 parts of γ-aminopropyltrimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.8 parts of dibutyltin dilaurate, and stir for 10 minutes under nitrogen protection. The material temperature must be lower than 50°C to obtain component B, which is then sealed and stored.

[0110] When in use, mix component A and component B evenly in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1.

[0111] Embodiment 4:

[0112] The preparation method of the two-component silicone sealant provided in this embodiment is as follows:

[0113] Preparation of component A:

[0114] Take 100 parts of end-hydroxyl-terminated polydimethylsiloxane 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 100nm 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 base material A (i.e. component A), and grind it for use.

[0115] Preparation of component B:

[0116] Add 200 parts of modified fluorosilicone polymer and 100 parts of carbon black into a planetary mixer and stir under vacuum (-0.09MPa). Stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B. After the base material is cooled to room temperature, add 50 parts of methyltrimethoxysilane, 25 parts of γ-aminopropyltrimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.8 parts of dibutyltin dilaurate. Stir for 10 minutes under nitrogen protection. The material temperature must be lower than 50°C to obtain component B, which is then sealed and stored.

[0117] When in use, mix component A and component B evenly in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1.

[0118] Comparative Example 1:

[0119] The preparation method of the two-component silicone sealant provided in this comparative example is as follows:

[0120] Preparation of component A:

[0121] Take 100 parts of end-hydroxyl-terminated polydimethylsiloxane 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 100nm 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 base material A (i.e. component A), and grind it for use.

[0122] Preparation of component B:

[0123] 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black are added to a planetary mixer and stirred in vacuum (-0.09 MPa). After the temperature is stabilized at 100°C, stir for 30 minutes to obtain base material B. After the base material is cooled to room temperature, 50 parts of methyltrimethoxysilane, 25 parts of γ-aminopropyltrimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.8 parts of dibutyltin dilaurate are added, and stirred for 10 minutes under nitrogen protection. The material temperature must be lower than 50°C to obtain component B, which is sealed and stored.

[0124] When in use, mix component A and component B evenly in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1.

[0125] Comparative Example 2

[0126] The preparation method of the two-component silicone sealant provided in this comparative example is as follows:

[0127] Preparation of component A:

[0128] Take 100 parts of end-hydroxyl-terminated polydimethylsiloxane 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 100nm 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 base material A (i.e. component A), and grind it for use.

[0129] Preparation of component B:

[0130] 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black are added to a planetary mixer and stirred in vacuum (-0.09 MPa). After the temperature is stabilized at 100°C, stir for 30 minutes to obtain base material B. After the base material is cooled to room temperature, 50 parts of phenyltriethoxysilane, 25 parts of γ-aminopropyltrimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.8 parts of dibutyltin dilaurate are added, and stirred for 10 minutes under nitrogen protection. The material temperature must be lower than 50°C to obtain component B, which is sealed and stored.

[0131] When in use, mix component A and component B evenly in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1.

[0132] Comparative Example 3:

[0133] The preparation method of the two-component silicone sealant provided in this comparative example is as follows:

[0134] Preparation of component A:

[0135] Take 100 parts of end-hydroxyl-terminated polydimethylsiloxane 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 100nm 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 base material A (i.e. component A), and grind it for use.

[0136] Preparation of component B:

[0137] Add 100 parts of α,ω-terminated hydroxyl polymethyltrifluoropropylsiloxane and 100 parts of carbon black into a planetary mixer and stir under vacuum (-0.09MPa). Stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B. After the base material is cooled to room temperature, add 50 parts of methyltrimethoxysilane, 25 parts of γ-aminopropyltrimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.8 parts of dibutyltin dilaurate. Stir for 10 minutes under nitrogen protection. The material temperature must be lower than 50°C to obtain component B, which is then sealed and stored.

[0138] Among them, the structural formula of α,ω-terminated hydroxyl polymethyl trifluoropropyl siloxane is

[0139]

[0140] n is 54.

[0141] When in use, mix component A and component B evenly in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1.

[0142] Comparative Example 4

[0143] The preparation method of the two-component silicone sealant provided in this comparative example is as follows:

[0144] Preparation of component A:

[0145] Take 100 parts of end-hydroxyl-terminated polydimethylsiloxane 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 100nm 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 base material A (i.e. component A), and grind it for use.

[0146] Preparation of component B:

[0147] Add 100 parts of modified fluorosilicone polymer and 100 parts of carbon black into a planetary mixer and stir under vacuum (-0.09MPa). Stir for 30 minutes when the temperature stabilizes at 100°C to obtain base material B. After the base material is cooled to room temperature, add 50 parts of methyltrimethoxysilane, 25 parts of γ-aminopropyltrimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.8 parts of dibutyltin dilaurate. Stir for 10 minutes under nitrogen protection. The material temperature must be lower than 50°C to obtain component B, which is then sealed and stored.

[0148] The manufacturing method of the modified fluorosilicone polymer is as follows:

[0149] Connect a three-necked flask equipped with a condensation reflux device and a tetrafluoroethylene stirring paddle to the nitrogen inlet and outlet, and introduce high-purity nitrogen. Add 1 mol of α, ω-terminated hydroxyl polymethyl trifluoropropyl siloxane, 1.5L tetrahydrofuran, and 4g of palladium carbon catalyst to the flask in sequence, stir evenly and heat to 60°C, then add 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 polymer. Subsequently, the crude product is heated to 130°C, stirred and vacuumed to remove unreacted trimethoxysilane, and the resulting oily liquid is the target product, the modified fluorosilicone polymer.

[0150] Among them, the structural formula of α,ω-terminated hydroxyl polymethyl trifluoropropyl siloxane is:

[0151] n is 54.

[0152] When in use, mix component A and component B evenly in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1.

[0153] The main differences between the two-component silicone sealants provided in the above embodiments and comparative examples are shown in Table 1.

[0154] Table 1. Comparison of raw material composition and preparation process between the examples and comparative examples

[0155]

[0156] a: Add 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s to component B of comparative example 1;

[0157] b: 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s was added to component B of Comparative Example 2, and phenyltriethoxysilane was used to replace the methyltrimethoxysilane in the example;

[0158] c: Add 100 parts of α,ω-terminated hydroxyl polymethyl trifluoropropyl siloxane to component B of comparative example 3;

[0159] d: 100 parts of a modified fluorosilicone polymer prepared from α,ω-terminated hydroxyl polymethyltrifluoropropylsiloxane and trimethoxysilane were added to component B of Comparative Example 4.

[0160] Component A and component B of the two-component silicone sealant prepared in the above examples and comparative examples were mixed uniformly in a planetary mixer in a vacuum according to a mixing volume ratio of 10:1, and then made into H-shaped test pieces for the following performance tests:

[0161] 23℃ tensile adhesion and -20℃ tensile adhesion: tested according to 5.9 of JG / T 475-2015.

[0162] 80℃ tensile adhesion: Test according to 5.9.2 of JG / T 475-2015 and calculate the retention rate according to 5.1.3.

[0163] Tensile adhesion test after immersion in 45℃ hot water for 1008h: The cured specimens were placed in a 45℃ constant temperature water bath and soaked for 1008h, then taken out and cured at room temperature for (24±4)h, then tested according to 5.9 of JG / T 475-2015 and the bonding failure area was calculated according to 5.1.3.

[0164] The test results are shown in Table 2.

[0165] Table 2. Performance test results of two-component silicone sealants prepared in Examples and Comparative Examples

[0166]

[0167] *CF stands for cohesive failure, AF stands for adhesive failure

[0168] By comparing these experimental results, the following conclusions can be drawn: using the modified fluorosilicone polymer prepared in the present invention as the polymer base material of component B, the -20°C tensile bonding strength, 80°C tensile retention rate, and adhesion after 1008h in 45°C hot water of the obtained two-component silicone sealant can be significantly improved.

[0169] It can be seen from the test results of Comparative Examples 1 and 2 that when the conventional dimethyl silicone oil is replaced by the modified fluorosilicone polymer prepared by the present invention, the -20°C tensile bonding strength, 80°C tensile retention rate and hot water resistance of the two-component silicone sealant are significantly improved.

[0170] It can be seen from the test results of Examples 2, 3, and 4 that as the amount of modified fluorosilicone polymer added increases, the high temperature resistance of the sealant will become better, but the strength will decrease.

[0171] It can be seen from the test results of Examples 1 and 2 that: when the preparation temperature of the B base material is low, the heat resistance and water resistance of the prepared two-component silicone sealant both decrease. This is because too low a preparation temperature of the B base material will cause the moisture content in the B component to exceed the standard, and a cross-linking reaction will occur spontaneously, consuming the reactive groups in the system, and ultimately causing the mechanical properties, heat resistance and water resistance of the obtained sealant to decrease.

[0172] In component B of Comparative Example 2, dimethyl silicone oil is used to replace the modified fluorosilicone polymer in Example 2, and phenyltriethoxysilane is used to replace the methyltrimethoxysilane in Example 2. The heat resistance of the resulting silicone sealant is improved compared with Comparative Example 1, but is still far inferior to that of Example 2, and has poor water resistance.

[0173] In component B of Comparative Example 3, the modified fluorosilicone polymer in Example 2 is replaced by unmodified α, ω-terminal hydroxyl polymethyltrifluoropropylsiloxane; in component B of Comparative Example 4, the modified fluorosilicone polymer prepared from α, ω-terminal hydroxyl polymethyltrifluoropropylsiloxane and trimethoxysilane is used to replace the modified fluorosilicone polymer in Example 2; the water resistance of the silicone sealants obtained in Comparative Examples 3 and 4 is greatly improved compared with that in Comparative Example 1, but is still worse than that in Example 2, and the heat resistance is not improved compared with that in Comparative Example 1.

[0174] 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.

[0175] 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 fluorosilicone polymer, characterized in that: Its structural formula is as follows: Among them, n is selected from an integer between 16 and 150, preferably an integer between 30 and 80, more preferably an integer between 40 and 70, more preferably an integer between 50 and 60, and more preferably 53, 54, 55 or 56.

2. A method for preparing the modified fluorosilicone polymer 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 fluorosilicone polymer; The reaction formula is as follows: Among them, n is selected from an integer between 16 and 150, preferably an integer between 30 and 80, more preferably an integer between 40 and 70, more preferably an integer between 50 and 60, and more preferably 53, 54, 55 or 56.

3. The method for preparing the modified fluorosilicone polymer 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 polymer according to claim 1 as a base polymer in the preparation of a two-component silicone sealant.

5. A two-component silicone sealant, characterized in that: The raw materials for its preparation contain the modified fluorosilicone polymer described in claim 1.

6. The two-component silicone sealant according to claim 5, 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: The base material consists of 50 to 250 parts of the modified fluorosilicone polymer and 50 to 150 parts of carbon black.

7. The two-component silicone sealant according to claim 6, 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; In parts by weight, the B component is prepared from raw materials including the following components: The base material consists of 80 to 220 parts of the modified fluorosilicone polymer and 90 to 110 parts of carbon black.

8. The two-component silicone sealant according to claim 7, characterized in that: The weight portion of the modified fluorosilicone polymer is 100 to 200 parts, more preferably 140 to 160 parts; and / or, the weight portion of the cross-linking agent is 48 to 52 parts; And / or, 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 to 12:1; and / or, the water content of the base material is lower than 1400 ppm, preferably lower than 500 ppm, more preferably 400 ppm to 460 ppm; 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 30000 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 150nm, and more preferably 80nm to 120nm; and / or, the viscosity of the dimethyl silicone oil at 25° C. is 300 mPa·s to 1000 mPa·s, preferably 350 mPa·s to 500 mPa·s; And / or, the crosslinking agent is selected from at least one of tetraethyl orthosilicate, propyl orthosilicate, polyethyl silicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, polymethyltriethoxysilane oligomer, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane and diphenyldiethoxysilane; 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 stirring the modified fluorosilicone polymer and carbon black at a temperature of 70° C. to 140° C. for 10 to 60 minutes to obtain a base material; after cooling to room temperature, adding the crosslinking agent, coupling agent and catalyst to the base material, stirring for 10 to 100 minutes under the protection of an inert gas to obtain component B; Preferably, the modified fluorosilicone polymer and carbon black are stirred under vacuum at a temperature of 80° C. to 120° C. for 20 min to 40 min; Preferably, the modified fluorosilicone polymer and carbon black are stirred under vacuum at a temperature of 90° C. to 110° C. for 25 min to 35 min.

Images