Modified fluorosilicon polymers, two-component silicone sealant, and methods of making the same

Abstract

The application discloses a modified fluorosilicon polymer, a two-component silicone sealant and a preparation method thereof. The structural formula of the modified fluorosilicon polymer is as follows. The two-component silicone sealant contains the modified fluorosilicon polymer in raw materials. The two-component silicone sealant prepared by using the modified fluorosilicon polymer provided by the application as a basic polymer to replace conventional dimethyl silicone oil, and by matching alpha, omega-dihydroxypolydimethylsiloxane, a crosslinking agent, a coupling agent and other components has higher normal temperature and low temperature strength, and has good heat resistance and water resistance, and solves the defects that the performance of the existing silicone sealant is reduced under high temperature and immersion conditions.

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 fluorosilicone polymer, a two-component silicone sealant and a preparation method thereof. BACKGROUND

[0002] The condensation type two-component room temperature vulcanization (RTV-2) silicone sealant can rapidly cross-link to form an elastomer with a certain hardness at room temperature. At present, the two-component silicone sealant has been widely used as a main product of sealing material in the fields of construction and industry. The sealing performance of the traditional two-component silicone sealant in the waterproof aspect is one of the key factors limiting the service life and stability. Moreover, under the influence of some special environments and construction conditions of long-term heating and humidity, the sealant must have excellent high-low temperature applicability, water resistance and thermal aging stability to meet the use requirements under specific conditions.

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

[0004] Patent CN111748315A prepares a high-adhesion water-boiling-resistant organic silicone insulation sealant, which mainly improves the heat resistance and water-boiling resistance of the sealant by synthesizing an adhesion promoter and a heat-resistant agent and then matching the production formula of the conventional sealant. This scheme needs to synthesize two new materials, and the synthesis route is relatively complex, which is not conducive to actual production. SUMMARY

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

[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 fluorosilicone polymer, which has the following structural formula:

[0008]

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

[0010] In a second aspect, the present application provides a preparation method of the modified fluorosilicone polymer, which comprises the following steps: under the protection of an inert gas, dehydrogenation condensation reaction of α, ω-hydroxyl polymethyl trifluoropropyl siloxane and dimethoxy phenyl silane occurs under the catalysis of a palladium-carbon catalyst, and the modified fluorosilicone polymer is obtained.

[0011] The reaction formula is as follows:

[0012]

[0013] Wherein, 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, more preferably 53, 54, 55 or 56.

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

[0015] In a fourth aspect, the present application provides a two-component silicone sealant, which contains the modified fluorosilicone polymer as a raw material.

[0016] Preferably, the two-component silicone sealant is composed of a component A and a component B, wherein the component A is prepared from raw materials including the following components:

[0017] 100 parts of α, ω-dihydroxypolydimethylsiloxane

[0018] 60-150 parts of filler

[0019] 5-25 parts of dimethyl silicone oil

[0020] The component B is prepared from raw materials including the following components:

[0021]

[0022] The base material is composed of 50-250 parts of the modified fluorosilicone polymer and 50-150 parts of carbon black.

[0023] In a fifth aspect, the present application provides a preparation method of the two-component silicone sealant, which comprises the following steps:

[0024] Preparation of the component A: the α, ω-dihydroxypolydimethylsiloxane, dimethyl silicone oil and filler are stirred and mixed at a temperature of 60-120°C for 10-200 min to obtain the component A;

[0025] Preparation of the component B: the modified fluorosilicone polymer and carbon black are stirred under vacuum at a temperature of 70-140°C for 10-60 min to obtain a base material; after cooling to room temperature, the crosslinking agent, coupling agent and catalyst are added to the base material, and stirred under inert gas protection for 10-100 min to obtain the component B.

[0026] The present application has the following advantages:

[0027] In order to solve the problems of poor high-low temperature performance and water resistance of the conventional two-component silicone sealant, the modified fluorosilicon polymer with multiple benzene ring side groups is prepared by dehydrogenation condensation of dimethoxyphenylsilane and alpha, omega-hydroxyl polymethyl trifluoropropyl siloxane under the catalysis of palladium-carbon catalyst, and the modified fluorosilicon polymer is used as a base polymer to prepare the two-component silicone sealant, so that the high-low temperature bonding strength, heat resistance and water resistance of the obtained two-component silicone sealant can be improved.

[0028] The two-component silicone sealant prepared by using the modified fluorosilicon polymer provided by the application as a base polymer to replace conventional dimethyl silicone oil and by combining alpha, omega-dihydroxyl polydimethylsiloxane, a crosslinking agent, a coupling agent and the like has high normal temperature and low temperature strength, good heat resistance and water resistance, and solves the defects of performance decline of the existing silicone sealant under high temperature and immersion conditions.

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

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

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

[0032] The terms "comprising" and "having" and any variations thereof in the application are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment including a series of steps is not limited to the listed steps or modules, but can optionally include steps not listed or can optionally include other steps inherent to the process, method, product or equipment.

[0033] In the application, "a plurality of" refers to two or more. "And / or", which describes the association relationship of the associated objects, means that there can be three relationships, for example, A and / or B can mean that 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] In some embodiments of the application, a modified fluorosilicon polymer is involved, and the structural formula is as follows:

[0035]

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

[0037] In some embodiments of the present application, a method for preparing a modified fluorosilicone polymer is provided, comprising the following steps: under the protection of inert gas, dehydrogenation condensation reaction of α, ω-hydroxyl polymethyl trifluoropropyl siloxane and dimethoxy phenyl silane is carried out under the catalysis of palladium-carbon catalyst, and the modified fluorosilicone polymer is obtained.

[0038] The reaction formula is as follows:

[0039]

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

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

[0042] In some embodiments, the ratio of the α, ω-hydroxyl polymethyl trifluoropropyl siloxane to 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 reaction temperature is 50-70℃, and the reaction time is 6-12 hours.

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

[0046] In some embodiments of the present application, the modified fluorosilicone polymer is used as a base polymer in the preparation of a two-component silicone sealant.

[0047] In some embodiments of the present application, a two-component silicone sealant is provided, and the raw material for preparing the two-component silicone sealant contains the modified fluorosilicone polymer of the present application.

[0048] In some embodiments, the two-component silicone sealant is composed of component A and component B, the component A is prepared from raw materials including the following components by weight parts:

[0049] α,ω-dihydroxypolydimethylsiloxane 100 parts

[0050] filler 60-150 parts

[0051] dimethyl silicone oil 5-25 parts;

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

[0053]

[0054] The base material is composed of 50-250 parts of the modified fluorosilicon polymer and 50-150 parts of carbon black.

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

[0056] α,ω-dihydroxypolydimethylsiloxane 100 parts

[0057] filler 90-110 parts

[0058] dimethyl silicone oil 8-12 parts;

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

[0060]

[0061] The base material is composed of 80-220 parts of the modified fluorosilicon polymer and 90-110 parts of carbon black.

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

[0063] In some embodiments, the weight parts of the crosslinking agent is 48-52 parts.

[0064] In some embodiments, the weight parts of the coupling agent is 48-52 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 400-460 ppm.

[0068] In some embodiments, the mixture of the A component and the B component is used in a volume ratio of 8 to 12: 1.

[0069] In some embodiments, the α,ω-dihydroxypolydimethylsiloxane has a viscosity of 5000 mPa s to 80000 mPa s at 25°C, preferably 1000 mPa s to 30000 mPa s, more preferably 18000 mPa s to 20000 mPa s.

[0070] In some embodiments, the filler is nano-active calcium carbonate having a particle size of 20 nm to 200 nm, preferably 60 nm to 150 nm, more preferably 80 nm to 120 nm.

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

[0072] In some embodiments, the cross-linking agent is selected from at least one of ethyl orthosilicate, propyl orthosilicate, ethyl polysilicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, polymethyltriethoxysilane oligomer, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

[0073] 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.

[0074] In some embodiments, the catalyst is selected from at least one of dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, isopropyl titanate, and n-butyl titanate.

[0075] In some embodiments of the present application, a method for preparing the two-component silicone sealant is provided, comprising the following steps:

[0076] Preparation of A component: stirring and mixing the α, ω-dihydroxyl polydimethylsiloxane, dimethyl silicone oil and filler at a temperature of 60-120℃ for 10-200 minutes to obtain A component;

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

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

[0079] Preparation of A component: stirring and mixing the α, ω-dihydroxyl polydimethylsiloxane, dimethyl silicone oil and filler at a temperature of 80-100℃ for 40-90 minutes to obtain A component;

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

[0081] In some embodiments, the modified fluorosilicon polymer and carbon black are stirred under vacuum at a temperature of 90-110℃ for 25-35 minutes.

[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, unless otherwise specified, refers to the viscosity at 25℃; the "parts", unless otherwise specified, refers to weight parts; the temperature range of room temperature refers to 15-30℃.

[0085] The preparation method of the modified fluorosilicon polymer in the following embodiments 1-4 is as follows:

[0086] A three-necked flask equipped with a condenser and a stirring blade of tetrafluoroethylene was connected to a nitrogen inlet and outlet, and high-purity nitrogen was introduced. 1 mol of α, ω-hydroxyl-terminated polymethyl trifluoropropyl siloxane, 1.5 L of tetrahydrofuran, and 4 g of palladium-carbon catalyst were sequentially added to the flask, stirred uniformly, and heated to 60°C, and then 3 mol of dimethoxyphenyl silane was added. The reaction was continued at 60°C for 8 hours, and 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. The solvent in the filtered mixture was then removed by a rotary evaporator under vacuum at 80°C to obtain a crude modified fluorosilicon polymer product. Subsequently, the obtained crude product was heated to 130°C, and unreacted dimethoxyphenyl silane was removed by stirring under vacuum to obtain an oily liquid as the target product, modified fluorosilicon polymer, with a yield of 94%. The reaction formula is as follows:

[0087]

[0088] wherein n is 54.

[0089] The infrared data of the product are as follows: no silicon hydroxyl stretching vibration peak is found at 3710 cm -1 , proving that the dehydrogenation reaction between silicon hydride 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.

[0090] Example 1:

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

[0092] Preparation of component A:

[0093] 100 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 20,000 mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400 mPa·s were added to a kneader and stirred and dispersed, and after 5 minutes, 100 parts of nano active calcium carbonate with a particle size of 100 nm was added during stirring to form a self-leveling base material, the reaction temperature was controlled at 90°C, and stirring and mixing were performed for 1 h to obtain the A base (i.e., component A), which was ground and reserved.

[0094] Preparation of component B:

[0095] 100 parts of modified fluorosilicon polymer and 100 parts of carbon black were added to a planetary mixer and stirred under vacuum (-0.09 MPa) until the temperature stabilized at 70°C, and then stirred for 30 min ，The B base is obtained, after the base is cooled to room temperature, 50 parts of methyl trimethoxysilane, 25 parts of γ-aminopropyl trimethoxysilane, 25 parts of γ-(2, 3-epoxypropoxy) propyl trimethoxysilane and 0.8 parts of dibutyltin dilaurate are added, and stirring is carried out under nitrogen protection for 10 min, and the material temperature needs to be lower than 50°C, to obtain the B component, which is sealed and stored.

[0096] When used, the A component and the B component are mixed uniformly in a planetary mixer under vacuum according to a mixing volume ratio of 10:1.

[0097] Example 2:

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

[0099] Preparation of the A component:

[0100] 100 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 20,000 mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400 mPa·s are added to a kneader for stirring and dispersion, 100 parts of nano active calcium carbonate with a particle size of 100 nm is added in the stirring process after 5 min, so that the glue completely covers the powder to form a self-leveling base, the reaction temperature is controlled to be 90°C, and stirring and mixing are carried out for 1 h to obtain the A base (i.e. the A component), which is ground and used.

[0101] Preparation of the B component:

[0102] 100 parts of modified fluorosilicon polymer and 100 parts of carbon black are added to a planetary mixer for stirring under vacuum (-0.09 MPa), and the temperature is stabilized at 100°C for stirring for 30 min to obtain the B base, after the base is cooled to room temperature, 50 parts of methyl trimethoxysilane, 25 parts of γ-aminopropyl trimethoxysilane, 25 parts of γ-(2, 3-epoxypropoxy) propyl trimethoxysilane and 0.8 parts of dibutyltin dilaurate are added, and stirring is carried out under nitrogen protection for 10 min, and the material temperature needs to be lower than 50°C, to obtain the B component, which is sealed and stored.

[0103] When used, the A component and the B component are mixed uniformly in a planetary mixer under vacuum according to a mixing volume ratio of 10:1.

[0104] Example 3:

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

[0106] Preparation of the A component:

[0107] Take 100 parts of viscosity 20000 mPa·s of hydroxyl-terminated 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 100 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 A base (i.e. A component), grind and reserve.

[0108] Preparation of B component:

[0109] Put 150 modified fluorosilicon polymers and 100 parts of carbon black into a planetary mixer to stir under vacuum (-0.09 MPa), and when the temperature stabilizes at 100℃, stir for 30 minutes to get B base. After the base cools 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, and the material temperature should be below 50℃. Get B component, seal and store.

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

[0111] Example 4:

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

[0113] Preparation of A component:

[0114] Take 100 parts of viscosity 20000 mPa·s of hydroxyl-terminated 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 100 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 A base (i.e. A component), grind and reserve.

[0115] Preparation of B component:

[0116] Put 200 modified fluorosilicon polymers and 100 parts of carbon black into a planetary mixer to stir under vacuum (-0.09 MPa), and when the temperature stabilizes at 100℃, stir for 30 minutes to get B base. After the base cools 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, and the material temperature should be below 50℃. Get B component, seal and store.

[0117] The A component and the B component are mixed again according to a mixing volume ratio of 10:1 in a planetary mixer under vacuum.

[0118] Comparative Example 1

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

[0120] Preparation of the A component:

[0121] 100 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400 mPa·s were added into a kneader for stirring and dispersion. After 5 minutes, 100 parts of nano active calcium carbonate with a particle size of 100 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°C, and the stirring and mixing were performed for 1 hour to obtain the A base (i.e., the A component), which was reserved after grinding.

[0122] Preparation of the B component:

[0123] 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s and 100 parts of carbon black were added into a planetary mixer for stirring under vacuum (-0.09 MPa). After the temperature was stabilized at 100°C for 30 minutes, the B base was obtained. After the base was 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 were added. The stirring was performed for 10 minutes under nitrogen protection, and the material temperature needed to be lower than 50°C to obtain the B component, which was stored in a sealed manner.

[0124] The A component and the B component are mixed again according to a mixing volume ratio of 10:1 in a planetary mixer under vacuum.

[0125] Comparative Example 2

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

[0127] Preparation of the A component:

[0128] 100 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s and 10 parts of dimethyl silicone oil with a viscosity of 400 mPa·s were added into a kneader for stirring and dispersion. After 5 minutes, 100 parts of nano active calcium carbonate with a particle size of 100 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°C, and the stirring and mixing were performed for 1 hour to obtain the A base (i.e., the A component), which was reserved after grinding.

[0129] Preparation of the B component:

[0130] 100 parts of dimethyl silicone oil with viscosity of 10000 mPa·s and 100 parts of carbon black were added into a planetary mixer and stirred under vacuum (-0.09 MPa), and after the temperature was stabilized at 100 ℃, the stirring was continued for 30 min to obtain a B base. After the base was cooled to room temperature, 50 parts of phenyl triethoxysilane, 25 parts of γ-aminopropyl trimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy) propyl trimethoxysilane and 0.8 parts of dibutyltin dilaurate were added, and stirred for 10 min under nitrogen protection, and the material temperature was required to be lower than 50 ℃ to obtain a B component, which was sealed and stored.

[0131] When used, the A component and the B component were mixed uniformly in a planetary mixer under 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 the present comparative example was as follows:

[0134] Preparation of the A component:

[0135] 100 parts of hydroxyl-terminated polydimethylsiloxane with viscosity of 20000 mPa·s and 10 parts of dimethyl silicone oil with viscosity of 400 mPa·s were added into a kneader and stirred and dispersed, and after 5 min, 100 parts of nano active calcium carbonate with particle size of 100 nm was 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 the stirring and mixing was continued for 1 h to obtain an A base (i.e. the A component), which was ground and stored.

[0136] Preparation of the B component:

[0137] 100 parts of α,ω-hydroxyl-terminated polymethyl trifluoropropylsiloxane and 100 parts of carbon black were added into a planetary mixer and stirred under vacuum (-0.09 MPa), and after the temperature was stabilized at 100 ℃, the stirring was continued for 30 min to obtain a B base. After the base was cooled to room temperature, 50 parts of methyl trimethoxysilane, 25 parts of γ-aminopropyl trimethoxysilane, 25 parts of γ-(2,3-epoxypropoxy) propyl trimethoxysilane and 0.8 parts of dibutyltin dilaurate were added, and stirred for 10 min under nitrogen protection, and the material temperature was required to be lower than 50 ℃ to obtain a B component, which was sealed and stored.

[0138] The structural formula of the α,ω-hydroxyl-terminated polymethyl trifluoropropylsiloxane is

[0139]

[0140] n is 54.

[0141] When used, the A component and the B component were mixed uniformly in a planetary mixer under 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 by the present comparative example is as follows:

[0144] Preparation of Component A:

[0145] Take 100 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 20,000 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, add 100 parts of nano active calcium carbonate with a particle size of 100 nm during stirring to make the glue completely cover the powder to form a self-leveling base, control the reaction temperature to be 90°C, and stir and mix for 1 hour to obtain the A base (i.e., Component A), which is ready for use after grinding.

[0146] Preparation of Component B:

[0147] Put 100 parts of modified fluorosilicon polymer and 100 parts of carbon black into a planetary stirrer to stir under vacuum (-0.09 MPa), and when the temperature stabilizes at 100°C, stir for 30 minutes to obtain the B base. After the base cools 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, with the material temperature being lower than 50°C, to obtain Component B, which is stored in a sealed manner.

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

[0149] 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. Into the flask, 1 mol of α,ω-hydroxyl-terminated polymethyltrifluoropropylsiloxane, 1.5 L of tetrahydrofuran, and 4 g of palladium-carbon catalyst are sequentially added, stirred uniformly, and heated to 60°C. Then, 3 mol of trimethoxysilane 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 mixed solution is removed by suction filtration through a Buchner funnel. Then, the solvent in the filtered mixed solution is removed by rotary evaporation under vacuum at 80°C, and the crude product of the modified fluorosilicon polymer is obtained. Subsequently, the obtained crude product is heated to 130°C, and unreacted trimethoxysilane is removed by stirring under vacuum to obtain the target product, the modified fluorosilicon polymer, in the form of an oily liquid.

[0150] The structural formula of the α,ω-hydroxyl-terminated polymethyltrifluoropropylsiloxane is as follows:

[0151] n is 54.

[0152] The A component and the B component prepared in the above examples and comparative examples were mixed in a planetary mixer under vacuum at a mixing volume ratio of 10:1.

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

[0154] Table 1. Comparison table of raw material components and preparation processes of examples and comparative examples

[0155]

[0156] a: 100 parts of dimethyl silicone oil with a viscosity of 10000 mPa·s was added to the B component of Comparative Example 1;

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

[0158] c: 100 parts of α,ω-hydroxyl terminated polymethyl trifluoropropyl siloxane was added to the B component of Comparative Example 3;

[0159] d: 100 parts of modified fluorosilicon polymer prepared from α,ω-hydroxyl terminated polymethyl trifluoropropyl siloxane and trimethoxysilane was added to the B component of Comparative Example 4.

[0160] The A component and the B component of the two-component silicone sealants prepared in the above examples and comparative examples were mixed in a planetary mixer under vacuum at a mixing volume ratio of 10:1, and then H-shaped test pieces were prepared for the following performance tests:

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

[0162] 80℃ tensile adhesion: tested according to 5.9.2 in JG / T 475-2015 and the retention rate was calculated according to 5.1.3.

[0163] Tensile adhesion test after 1008h hot water immersion at 45℃: the well-maintained test pieces were taken out after being immersed in a constant temperature water bath at 45℃ for 1008h, and then maintained at room temperature for (24±4)h. The adhesive failure area was tested according to 5.9 in JG / T 475-2015 and the adhesive 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 the two-component silicone sealants prepared in the examples and comparative examples

[0166]

[0167] CF represents cohesive failure, AF represents adhesive failure

[0168] By comparing the test results, the following conclusions can be drawn: the modified fluorosilicone polymer prepared in the application as the B component of the polymer base can significantly improve the tensile bonding strength at -20℃, the tensile retention rate at 80℃, and the bonding property after 1008h of hot water at 45℃ of the obtained two-component silicone sealant.

[0169] From the test results of Comparative Examples 1 and 2, it can be seen that when the modified fluorosilicone polymer prepared in the application is used to replace the conventional dimethyl silicone oil, the tensile bonding strength at -20℃, the tensile retention rate at 80℃, and the hot water resistance of the two-component silicone sealant are significantly improved.

[0170] From the test results of Examples 2, 3, and 4, it can be seen that as the amount of the modified fluorosilicone polymer increases, the high-temperature resistance of the sealant becomes better, but the strength decreases.

[0171] From the test results of Examples 1 and 2, it can be seen that when the preparation temperature of the B base is too low, the heat resistance and water resistance of the prepared two-component silicone sealant decrease, because the water content in the B component exceeds the standard when the preparation temperature of the B base is too low, which causes self-crosslinking reaction and consumes the reactive groups in the system, ultimately leading to the decrease of the mechanical properties, heat resistance, and water resistance of the obtained sealant.

[0172] In the B component of Comparative Example 2, the modified fluorosilicone polymer in Example 2 is replaced with dimethyl silicone oil, and the methyl trimethoxysilane in Example 2 is replaced with phenyl triethoxysilane. The heat resistance of the obtained silicone sealant is improved compared with Comparative Example 1, but it is still much worse than Example 2, and the water resistance is poor.

[0173] In the B component of Comparative Example 3, the modified fluorosilicone polymer in Example 2 is replaced with unmodified α,ω-hydroxyl-terminated polymethyl trifluoropropylsiloxane; in the B component of Comparative Example 4, the modified fluorosilicone polymer prepared from α,ω-hydroxyl-terminated polymethyl trifluoropropylsiloxane 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 Comparative Example 1, but it is still worse than Example 2, and the heat resistance is not improved compared with Comparative Example 1.

[0174] The technical features of the above-described examples can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described examples are described, but as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present disclosure.

[0175] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A modified fluorosilicon polymer characterized in that, The structural formula is as follows: ； n is an integer selected from 16-150.

2. The modified fluorosilicon polymer of claim 1, wherein, n is an integer selected from 30-80.

3. The modified fluorosilicon polymer of claim 2, wherein, n is an integer selected from 40-70.

4. The modified fluorosilicon polymer of claim 3, wherein, n is an integer selected from 50-60.

5. The modified fluorosilicon polymer of claim 4, wherein, n is 53, 54, 55 or 56.

6. A method of preparing the modified fluorosilicon polymer of claim 1, characterized by, The method comprises the following steps: under the protection of inert gas, α, ω-terminally hydroxyl poly-methyl trifluoropropyl siloxane and dimethoxy phenyl silane are subjected to dehydrogenation condensation reaction under the catalysis of palladium-carbon catalyst, thus obtaining the modified fluorosilicon polymer. The reaction formula is as follows: ； n is an integer selected from 16-150.

7. The method for preparing the modified fluorosilicone polymer according to claim 6, characterized in that, n is an integer selected from 30-80.

8. The method for preparing the modified fluorosilicone polymer according to claim 7, characterized in that, n is an integer selected from 40-70.

9. The method for preparing the modified fluorosilicone polymer according to claim 8, characterized in that, n is an integer selected from 50-60.

10. The method for preparing the modified fluorosilicone polymer according to claim 9, characterized in that, n is 53, 54, 55 or 56.

11. The method of claim 6-10, wherein the modified fluorosilicon polymer is prepared by the process comprising: The molar ratio of the α, ω-terminally hydroxyl poly-methyl trifluoropropyl siloxane and dimethoxy phenyl silane is 1:2-4; And / or, the ratio of the α, ω-terminally hydroxyl poly-methyl trifluoropropyl siloxane to palladium-carbon catalyst is 1 mol:3g-5g; And / or, the reaction is carried out in an organic solvent; And / or, the temperature of the reaction is 50-70℃, and the time is 6-12 hours.

12. The method for preparing the modified fluorosilicone polymer according to claim 11, characterized in that, The organic solvent is tetrahydrofuran.

13. The method for preparing the modified fluorosilicone polymer according to claim 11, characterized in that, The temperature of the reaction is 55-65℃, and the time is 7-9 hours.

14. Use of the modified fluorosilicon polymer of any one of claims 1-5 as a base polymer in the preparation of a two-component silicone sealant.

15. A two-component silicone sealant, characterized by, The preparation raw materials contain the modified fluorosilicon polymer of any one of claims 1-5.

16. The two-component silicone sealant according to claim 15, characterized in that, The A component is prepared from raw materials including the following components: α, ω-dihydroxyl polydimethyl siloxane 100 parts Filler 60-150 parts Dimethyl silicone oil 5-25 parts; The B component is prepared from raw materials including the following components: Base material 100-400 parts Crosslinking agent 15-60 parts Coupling agent 15-60 parts Catalyst 0.1-1.5 parts; The base material is composed of 50-250 parts of the modified fluorosilicon polymer and 50-150 parts of carbon black.

17. The two-component silicone sealant according to claim 16, characterized in that The A component is prepared from raw materials including the following components: α, ω-dihydroxyl polydimethyl siloxane 100 parts Filler 90-110 parts Dimethyl silicone oil 8-12 parts; The B component is prepared from raw materials including the following components: Base material 170-330 parts Crosslinking agent 45-55 parts Coupling agent 45-55 parts Catalyst 0.8-1.2 parts; The base material is composed of 80-220 parts of the modified fluorosilicon polymer and 90-110 parts of carbon black.

18. The two-component silicone sealant according to claim 17, characterized in that, The weight of the modified fluorosilicon polymer is 100-200 parts; And / or, the weight of the crosslinking agent is 48-52 parts; And / or, the weight of the coupling agent is 48-52 parts.

19. The two-component silicone sealant according to claim 18, characterized in that, The weight of the modified fluorosilicon polymer is 140-160 parts.

20. Two-component silicone sealant according to any one of claims 16 to 19, characterized in that The mixing volume ratio of the A component and the B component is 8-12:1 when used; And / or, the water content of the base material is less than 1400 ppm; and / or, the viscosity of the alpha, omega-dihydroxypolydimethylsiloxane at 25℃ is 5000mPa s to 80000mPa s; and / or, the filler is nano active calcium carbonate, and the particle size of the nano active calcium carbonate is 20nm to 200nm; and / or, the viscosity of the dimethicone at 25℃ is 300mPa s to 1000mPa s; and / or, the cross-linking agent is at least one selected from the group consisting of tetraethyl orthosilicate, tetrapropyl orthosilicate, polyethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, polymethyltriethoxysilane oligomer, phenyltrimethoxysilane, phenyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane; and / or, the coupling agent is at least one selected from the group consisting of gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, epoxycyclohexylmethyl dimethoxysilane, epoxycyclohexylmethyl diethoxysilane, chloropropyltrimethoxysilane, chloropropyltriethoxysilane, gamma-(2,3-epoxypropoxy)propyltrimethoxysilane, gamma-aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-aminopropylmethyldimethoxysilane, gamma-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, anilinomethyltrimethoxysilane, anilinomethyltriethoxysilane, gamma-isocyanatopropyltrimethoxysilane, and divinylaminopropyltrimethoxysilane; and / or, the catalyst is at least one selected from the group consisting of dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, isopropyl titanate, and n-butyl titanate.

21. The two-component silicone sealant according to claim 20, characterized in that, The water content of the base is less than 500ppm.

22. The two-component silicone sealant according to claim 21, characterized in that, The water content of the base is 400ppm to 460ppm.

23. The two-component silicone sealant according to any one of claims 16-19, characterized in that, The viscosity of the alpha, omega-dihydroxypolydimethylsiloxane at 25℃ is 1000mPa s to 30000mPa s.

24. The two-component silicone sealant according to claim 23, characterized in that, The viscosity of the alpha, omega-dihydroxypolydimethylsiloxane at 25℃ is 18000mPa s to 20000mPa s.

25. The two-component silicone sealant of claim 20, wherein, The particle size of the filler is 60nm to 150nm.

26. The two-component silicone sealant according to claim 25, characterized in that, The particle size of the filler is 80nm to 120nm.

27. The two-part silicone sealant of claim 20, wherein, The viscosity of the dimethicone at 25℃ is 350mPa s to 500mPa s.

28. A process for the preparation of a two-component silicone sealant according to any one of claims 16 to 27, characterized in that, The method comprises the following steps: Preparation of the A component: the alpha, omega-dihydroxypolydimethylsiloxane, dimethicone, and filler are stirred and mixed at a temperature of 60℃ to 120℃ for 10min to 200min to obtain the A component; The method comprises the following steps: Preparation of B component: the modified fluorosilicon polymer and carbon black are vacuum stirred at a temperature of 70-140°C for 10-60 minutes to obtain a base; after cooling to room temperature, the crosslinking agent, coupling agent and catalyst are added to the base, and stirred under inert gas protection for 10-100 minutes to obtain B component.

29. The method of making a two-part silicone sealant according to claim 28, wherein, The modified fluorosilicon polymer and carbon black are vacuum stirred at a temperature of 80-120°C for 20-40 minutes.

30. The method of making a two-part silicone sealant according to claim 29, wherein, The modified fluorosilicon polymer and carbon black are vacuum stirred at a temperature of 90-110°C for 25-35 minutes. The modified fluorosilicon polymer and carbon black are vacuum stirred at a temperature of 90-110°C for 25-35 minutes.

Images