Application of alkoxy-terminated polysiloxane

Abstract

The invention relates to the technical field of high-molecular compounds, and discloses application of alkoxy-terminated polysiloxane. The preparation method of the alkoxy-terminated polysiloxane comprises the following steps: under the protection of nitrogen, uniformly mixing double-end vinyl polydimethylsiloxane and a platinum catalyst, keeping the temperature at 40-50 DEG C for 0.5-1 hour, adding hydrogen-containing alkoxy silane, keeping the temperature at 100-120 DEG C to react for 3-6 hours, and vacuumizing to remove a low-molecular product, thereby obtaining the alkoxy-terminated polysiloxane. The prepared alkoxy-terminated polysiloxane has excellent storage stability, can be used for preparing a silicone sealant, and the prepared silicone sealant has excellent mechanical properties, good humidity and heat resistance and good flame retardance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high-molecular compounds and discloses application of alkoxy-terminated polysiloxane. BACKGROUND

[0002] Polysiloxane is a kind of high-molecular material with a main chain of repeating Si-O-Si and is widely applied in the fields of coatings, sealants, electronic packaging materials and the like. Silicone sealants prepared from alkoxy-terminated polysiloxane have high storage stability and good adhesion to inorganic substrates, but still need to be improved in the synergistic optimization of flame retardancy, moisture resistance, strength and toughness. Although the commonly used flame retardants in the industry can improve the flame retardancy, they have poor compatibility with the sealant matrix, which not only leads to significant decrease in mechanical properties such as tensile strength and elongation at break, but also leads to internal defects, weakens moisture resistance and affects application. SUMMARY

[0003] The application aims to provide application of alkoxy-terminated polysiloxane to solve the problems in the background.

[0004] To solve the above technical problems, the application provides the following technical scheme: application of alkoxy-terminated polysiloxane: can be used for preparing silicone sealant, the silicone sealant comprises component A and component B: the component A comprises the following raw materials, and the mass fraction is: 100-120 parts of hydroxyl-terminated polysiloxane, 50-60 parts of silicone oil composition, 40-50 parts of amino-modified filler, and 10-15 parts of flame retardant; the component B comprises the following raw materials, and the mass fraction is: 100-120 parts of alkoxy-terminated polysiloxane, 200-260 parts of silicone oil modified filler, and 10-15 parts of crosslinking agent; the silicone oil composition is phosphorus-containing silicone oil and amino silicone oil with a mass ratio of 1: (1-1.5).

[0005] Preparation method of alkoxy-terminated polysiloxane: under the protection of nitrogen, double-end vinyl polydimethylsiloxane and platinum gold catalyst are uniformly mixed, 40-50 DEG C is kept for 0.5-1 h, hydrogen-containing alkoxy silane is added, and the mixture is kept at 100-120 DEG C for 3-6 h, low-molecular products are removed by vacuumizing, and alkoxy-terminated polysiloxane is obtained.

[0006] More preferably, the alkoxy-terminated polysiloxane comprises the following raw materials, and the mass fraction is: 180-220 parts of double-end vinyl polydimethylsiloxane, 0.01-0.05 parts of platinum gold catalyst, and 0.5-2 parts of hydrogen-containing alkoxy silane.

[0007] More preferably, the viscosity of the double-end vinyl polydimethylsiloxane is 100000 mPa·s, the vinyl content is 0.06%, the platinum catalyst is a Kist catalyst with a Pt content of 20%, and the hydrogen-containing alkoxysilane is trimethoxysilane.

[0008] More preferably, the preparation of the phosphorus-containing silicone oil comprises the following steps: mixing a double-end epoxy silicone oil and diisooctyl phosphoric acid under nitrogen protection, stirring and heating to 95-100°C, stirring and reacting for 6-8 hours, and distilling under reduced pressure to obtain the phosphorus-containing silicone oil; the molar ratio of the double-end epoxy silicone oil to diisooctyl phosphoric acid is 1: (2-3).

[0009] More preferably, the preparation of the amino-modified filler comprises the following steps: adding an amino silane coupling agent to a mixed solution of ethanol and water, adjusting the pH to 4-5, stirring for 2-5 minutes, heating to 60-70°C, adding the filler, and stirring and keeping warm for 3-5 hours, and then filtering, washing, and drying to obtain the amino-modified filler; the amino-modified filler comprises the following raw materials in terms of mass fraction: 0.5-1 part of the amino silane coupling agent and 10-15 parts of the filler.

[0010] More preferably, the silicone oil-modified filler is an epoxy silicone oil-modified amino-modified filler, and the preparation comprises the following steps: stirring the amino-modified filler in xylene until uniform, adding double-end epoxy silicone oil, stirring until uniform, heating to 70-80°C, stirring and keeping warm for 2-3 hours, and then taking the solid to obtain the epoxy silicone oil-modified calcium carbonate.

[0011] More preferably, the silicone oil-modified filler comprises the following raw materials in terms of mass fraction: 10-15 parts of the amino-modified filler and 5-9 parts of the double-end epoxy silicone oil.

[0012] More preferably, the preparation of the flame retardant comprises the following steps: S1: under nitrogen protection, adding phenyl dichlorophosphate into tetrahydrofuran, stirring uniformly under ice bath conditions, adding triethylamine, keeping stirring, and adding hydroxyethyl acrylate tetrahydrofuran mixture at a uniform speed for 2-3 hours, stirring for 4-6 hours after the addition is completed, adding 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, continuing to stir for 10-12 hours, and removing the solvent under reduced pressure to obtain a double-bond modified flame retardant; S2: stirring 2-mercapto benzimidazole in ethanol until uniform, heating to reflux, adding 2-bromoethylamine hydrobromide in ethanol at a uniform speed for 2-3 hours, refluxing for 24-30 hours, concentrating to obtain white solid, adding water to stir and dissolve, adjusting the pH to 7-8 with sodium bicarbonate, and extracting to obtain a diamino-modified mercaptoimidazole; S3: stirring the double-bond modified flame retardant and the diamino-modified mercaptoimidazole in a mixed solution of tetrahydrofuran and ethanol until uniform, adding a photoinitiator, reacting under ultraviolet light for 5-10 minutes, and removing the solvent to obtain the flame retardant.

[0013] More preferably, the double-bonded flame retardant comprises the following raw materials in parts by mass: 20-25 parts of phenyl phosphorodichloridate, 20-25 parts of triethylamine, 10-14 parts of hydroxyethyl acrylate, 10-12 parts of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; the diamino-modified mercapto imidazole comprises the following raw materials in parts by mass: 10-12 parts of 2-mercapto benzimidazole, 35-45 parts of 2-bromoethylamine hydrobromide; the flame retardant comprises the following raw materials in parts by mass: 9-10 parts of double-bonded flame retardant, 4-5 parts of diamino-modified mercapto imidazole, 0.03-0.05 parts of photoinitiator.

[0014] More preferably, the crosslinking agent is methyl trimethoxysilane and γ-(2,3-epoxypropoxy) propyl trimethoxysilane in a mass ratio of (3-5):1; the hydroxyl-terminated polysiloxane is hydroxyl-terminated polymethylsiloxane.

[0015] More preferably, the filler comprises one or more of quartz powder, calcium carbonate, carbon black, white carbon black, aluminum hydroxide, and aluminum oxide.

[0016] More preferably, the filler is calcium carbonate.

[0017] More preferably, the preparation process of the silicone sealant based on the alkoxy-terminated polysiloxane comprises the following steps: taking hydroxyl-terminated polysiloxane, silicone oil composition, amino-modified filler, and flame retardant, mixing uniformly, vacuum defoaming to obtain component A; taking alkoxy-terminated polysiloxane and silicone oil-modified filler, kneading in a kneader, vacuum water removal, and then adding a crosslinking agent after cooling to room temperature, mixing uniformly, and vacuum defoaming to obtain component B; mixing the two components uniformly to obtain the silicone sealant.

[0018] Compared with the prior art, the silicone sealant has the following beneficial effects: the silicone oil capable of subsequent crosslinking is introduced into the silicone sealant as a whole to enhance the mechanical properties; the phosphorus-containing silicone oil and the amino silicone oil are introduced into component A, which are compatible with the polysiloxane matrix, the amino silicone oil can participate in subsequent crosslinking, and the phosphorus-containing silicone oil is used to improve the flame retardancy; the amino-modified calcium carbonate and the flame retardant are also added into component A, both of which contain amino groups, and the compatibility with the sealant matrix is improved through crosslinking reaction with the epoxy groups in component B, and both of which are crosslinkable short chains, which can improve the compactness of the crosslinking network, thereby improving the strength and moisture resistance; the epoxy group-containing silicone oil is used to modify the calcium carbonate in component B, which improves the dispersibility of the filler and enables the filler to crosslink with the amino groups in component A, and the crosslinking agent also contains γ-(2,3-epoxypropoxy) propyl trimethoxysilane, which enhances the overall crosslinking degree.

[0019] In summary, this solution improves the crosslinking degree of the sealant system by introducing long-chain silicone oil containing amino / epoxy groups, fillers modified with aminosilane coupling agents, and small-molecule flame retardants containing amino groups. Due to the combined effect of long and short chains, the crosslinking network possesses both density and toughness, resulting in a crosslinked product with good strength, toughness, and resistance to damp heat. Furthermore, the introduction of phosphorus-containing silicone oil with good compatibility with polysiloxanes and small-molecule flame retardants that can participate in crosslinking both exhibit good compatibility with the matrix. This improves flame retardancy without affecting other overall properties, ultimately producing a silicone sealant that combines flame retardancy, resistance to damp heat, mechanical strength, and toughness. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that there are no special restrictions on the suppliers of any of the raw materials involved in this invention. Exemplary examples include: hydroxyl-terminated polymethylsiloxane (viscosity 80000 mPa·s); amino silicone oil (viscosity 1000 mPa·s); dual-terminated epoxy silicone oil (molecular weight 2000); aminosilane coupling agent (KH550); calcium carbonate (HN-70); dual-terminated vinyl polydimethylsiloxane (viscosity 100000 mPa·s, vinyl content 0.06%); platinum catalyst (Castel catalyst with 20% Pt content). Unless otherwise specified, all figures below are parts by weight or mass ratios. Preparation of alkoxy-terminated polysiloxane: Under nitrogen protection, 200 parts of divinyl-terminated polydimethylsiloxane and 0.01 parts of platinum catalyst were mixed evenly and kept at 45°C for 0.5 h. Then, 1.1 parts of trimethoxysilane were added and reacted at 120°C for 5 h. Low molecular weight products were removed by vacuum to obtain alkoxy-terminated polysiloxane.

[0022] Example 1: S1: 40 parts of double-ended epoxy silicone oil and 13 parts of diisooctyl phosphoric acid were mixed and stirred under nitrogen protection and heated to 100°C. The mixture was stirred and reacted for 6 hours. The mixture was then distilled under reduced pressure to obtain phosphorus-containing silicone oil. S2: Add 0.5 parts of aminosilane coupling agent to a mixed solution of ethanol and water, adjust the pH to 5, stir for 2 minutes, heat to 60°C, add 12 parts of calcium carbonate, keep warm and stir for 5 hours, filter, wash, and dry to obtain amino-modified calcium carbonate; take 10 parts of amino-modified calcium carbonate and add it to 150 parts of xylene, add 9 parts of double-ended epoxy silicone oil, stir evenly, heat to 80°C, keep warm and stir for 3 hours, take the solid to obtain epoxy silicone oil modified calcium carbonate; S3: Under nitrogen protection, 21 parts of phenyl dichloride phosphate were added to 100 parts of tetrahydrofuran and stirred in an ice bath at 0°C for 10 min. Then, 25 parts of triethylamine were added and stirred until homogeneous. The mixture of 12 parts of hydroxyethyl acrylate and 30 parts of tetrahydrofuran was added dropwise at a uniform rate over 2 h. After the addition was complete, the mixture was stirred for 6 h. Then, 12 parts of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide were added and stirred for another 12 h. The solvent was removed under reduced pressure to obtain the double-bonded flame retardant. S4: Add 10 parts of 2-thiol-benzoimidazole to 80 parts of ethanol, stir well, heat to reflux, and add 40 parts of a mixture of 2-bromoethylamine hydrobromide and 50 parts of ethanol dropwise at a uniform rate over 2 hours. Reflux for 24 hours, concentrate to obtain a white solid, add 400 parts of water and stir to dissolve, add sodium bicarbonate to adjust the pH to 8, add dichloromethane for extraction, combine the extracts and concentrate to obtain diamino-modified mercaptoimidazole; S5: 9 parts of double-bonded flame retardant and 5 parts of diamino-modified mercaptoimidazole were added to a mixed solution of 40 parts of tetrahydrofuran and 40 parts of ethanol, stirred evenly, 0.04 parts of photoinitiator 1173 were added, and the mixture was reacted under 15mW / cm² ultraviolet light for 10 min. The solvent was removed to obtain the flame retardant. S6: Take 100 parts of hydroxyl-terminated polymethylsiloxane, 55 parts of silicone oil composition, 45 parts of amino-modified calcium carbonate, and 12 parts of flame retardant, mix them evenly, and degas under vacuum to obtain component A; the silicone oil composition is phosphorus-containing silicone oil and amino silicone oil in a mass ratio of 1:1.5; take 100 parts of alkoxy-terminated polysiloxane and 250 parts of epoxy-modified calcium carbonate, knead them in a kneader at 120°C, remove water under vacuum, cool to room temperature, add 12 parts of crosslinking agent, mix evenly, and degas under vacuum to obtain component B; the crosslinking agent is methyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in a mass ratio of 4:1; mix the two components evenly to obtain silicone sealant.

[0023] Example 2: S1: 40 parts of double-ended epoxy silicone oil and 13 parts of diisooctyl phosphoric acid were mixed and stirred under nitrogen protection and heated to 100°C. The mixture was stirred and reacted for 6 hours. The mixture was then distilled under reduced pressure to obtain phosphorus-containing silicone oil. S2: Add 0.5 parts of aminosilane coupling agent to a mixed solution of ethanol and water, adjust the pH to 5, stir for 2 min, heat to 60℃, add 10 parts of calcium carbonate, keep warm and stir for 5 h, filter, wash and dry to obtain amino-modified calcium carbonate; take 10 parts of amino-modified calcium carbonate and add it to 150 parts of xylene, add 6 parts of double-ended epoxy silicone oil, stir evenly, heat to 80℃, keep warm and stir for 3 h, take the solid to obtain epoxy silicone oil modified calcium carbonate; S3: Under nitrogen protection, 20 parts of phenyl dichloride phosphate were added to 100 parts of tetrahydrofuran and stirred in an ice bath at 0°C for 10 min. Then, 20 parts of triethylamine were added and stirred until homogeneous. The mixture of 11 parts of hydroxyethyl acrylate and 30 parts of tetrahydrofuran was added dropwise at a uniform rate over 2 h. After the addition was complete, the mixture was stirred for 6 h. Then, 10 parts of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide were added and the mixture was stirred for 12 h. The solvent was removed under reduced pressure to obtain the double-bonded flame retardant. S4: Add 10 parts of 2-thiol-benzoimidazole to 80 parts of ethanol, stir well, heat to reflux, and add 40 parts of a mixture of 2-bromoethylamine hydrobromide and 50 parts of ethanol dropwise at a uniform rate over 2 hours. Reflux for 24 hours, concentrate to obtain a white solid, add 400 parts of water and stir to dissolve, add sodium bicarbonate to adjust the pH to 8, add dichloromethane for extraction, combine the extracts and concentrate to obtain diamino-modified mercaptoimidazole; S5: 9 parts of double-bonded flame retardant and 4 parts of diamino-modified mercaptoimidazole were added to a mixed solution of 40 parts of tetrahydrofuran and 40 parts of ethanol, stirred evenly, and 0.04 parts of photoinitiator 1173 were added. The mixture was reacted under 15mW / cm² ultraviolet light for 10 min, and the solvent was removed to obtain the flame retardant. S6: Take 100 parts of hydroxyl-terminated polymethylsiloxane, 50 parts of silicone oil composition, 40 parts of amino-modified calcium carbonate, and 15 parts of flame retardant, mix them evenly, and degas under vacuum to obtain component A; the silicone oil composition is a phosphorus-containing silicone oil and amino silicone oil in a mass ratio of 1:1; Take 100 parts of alkoxy-terminated polysiloxane and 260 parts of epoxy-modified calcium carbonate, knead them in a kneader at 120°C, remove water under vacuum, cool to room temperature, and then add 14 parts of crosslinking agent, mix evenly, and degas under vacuum to obtain component B; the crosslinking agent is methyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in a mass ratio of 5:1; mix the two components evenly to obtain silicone sealant.

[0024] Example 3: S1: 40 parts of double-ended epoxy silicone oil and 13 parts of diisooctyl phosphoric acid were mixed and stirred under nitrogen protection and heated to 100°C. The mixture was stirred and reacted for 6 hours. The mixture was then distilled under reduced pressure to obtain phosphorus-containing silicone oil. S2: Add 1 part of aminosilane coupling agent to a mixed solution of ethanol and water, adjust the pH to 5, stir for 2 min, heat to 60℃, add 15 parts of calcium carbonate, keep warm and stir for 5 h, filter, wash and dry to obtain amino-modified calcium carbonate; take 15 parts of amino-modified calcium carbonate and add it to 150 parts of xylene, add 9 parts of double-ended epoxy silicone oil, stir evenly, heat to 80℃, keep warm and stir for 3 h, take the solid to obtain epoxy silicone oil modified calcium carbonate; S3: Under nitrogen protection, 25 parts of phenyl dichloride phosphate were added to 100 parts of tetrahydrofuran and stirred in an ice bath at 0°C for 10 min. Then, 25 parts of triethylamine were added and stirred until homogeneous. The mixture of 12 parts of hydroxyethyl acrylate and 30 parts of tetrahydrofuran was added dropwise at a uniform rate over 2 h. After the addition was complete, the mixture was stirred for 6 h. Then, 12 parts of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide were added and the mixture was stirred for another 12 h. The solvent was removed under reduced pressure to obtain the double-bonded flame retardant. S4: Add 12 parts of 2-thiol-benzoimidazole to 80 parts of ethanol, stir well, heat to reflux, and add 40 parts of a mixture of 2-bromoethylamine hydrobromide and 50 parts of ethanol dropwise at a uniform rate over 2 hours. Reflux for 24 hours, concentrate to obtain a white solid, add 400 parts of water and stir to dissolve, add sodium bicarbonate to adjust the pH to 8, add dichloromethane for extraction, combine the extracts and concentrate to obtain diamino-modified mercaptoimidazole; S5: 10 parts of double-bonded flame retardant and 5 parts of diamino-modified mercaptoimidazole were added to a mixed solution of 40 parts of tetrahydrofuran and 40 parts of ethanol, stirred evenly, 0.04 parts of photoinitiator 1173 were added, and the mixture was reacted under 15mW / cm² ultraviolet light for 10 min. The solvent was removed to obtain the flame retardant. S6: Take 100 parts of hydroxyl-terminated polymethylsiloxane, 60 parts of silicone oil composition, 50 parts of amino-modified calcium carbonate, and 10 parts of flame retardant, mix them evenly, and degas under vacuum to obtain component A; the silicone oil composition is phosphorus-containing silicone oil and amino silicone oil in a mass ratio of 1:1.5; take 100 parts of alkoxy-terminated polysiloxane and 230 parts of epoxy-modified calcium carbonate, knead them in a kneader at 120°C, remove water under vacuum, cool to room temperature, and then add 12 parts of crosslinking agent, mix evenly, and degas under vacuum to obtain component B; the crosslinking agent is methyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in a mass ratio of 3:1; mix the two components evenly to obtain silicone sealant.

[0025] Comparative Example 1 (2-Mercaptobenzoimidazole replaces diamino-modified mercaptoimidazole, the rest is the same as in Example 1): S1: 40 parts of double-ended epoxy silicone oil and 13 parts of diisooctyl phosphoric acid are mixed and heated to 100°C under nitrogen protection, stirred and reacted for 6 hours, and then distilled under reduced pressure to obtain phosphorus-containing silicone oil. S2: Add 0.5 parts of aminosilane coupling agent to a mixed solution of ethanol and water, adjust the pH to 5, stir for 2 minutes, heat to 60°C, add 12 parts of calcium carbonate, keep warm and stir for 5 hours, filter, wash, and dry to obtain amino-modified calcium carbonate; take 10 parts of amino-modified calcium carbonate and add it to 150 parts of xylene, add 9 parts of double-ended epoxy silicone oil, stir evenly, heat to 80°C, keep warm and stir for 3 hours, take the solid to obtain epoxy silicone oil modified calcium carbonate; S3: Under nitrogen protection, 21 parts of phenyl dichloride phosphate were added to 100 parts of tetrahydrofuran and stirred in an ice bath at 0°C for 10 min. Then, 25 parts of triethylamine were added and stirred until homogeneous. The mixture of 12 parts of hydroxyethyl acrylate and 30 parts of tetrahydrofuran was added dropwise at a uniform rate over 2 h. After the addition was complete, the mixture was stirred for 6 h. Then, 12 parts of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide were added and stirred for another 12 h. The solvent was removed under reduced pressure to obtain the double-bonded flame retardant. S4: 9 parts of double-bonded flame retardant and 2 parts of 2-thiol-benzoimidazole were added to a mixed solution of 40 parts of tetrahydrofuran and 40 parts of ethanol, stirred evenly, and 0.04 parts of photoinitiator 1173 were added. The mixture was reacted under 15mW / cm² ultraviolet light for 10 min, and the solvent was removed to obtain the flame retardant. S5: Take 100 parts of hydroxyl-terminated polymethylsiloxane, 55 parts of silicone oil composition, 45 parts of amino-modified calcium carbonate, and 12 parts of flame retardant, mix them evenly, and degas under vacuum to obtain component A; the silicone oil composition is phosphorus-containing silicone oil and amino silicone oil in a mass ratio of 1:1.5; take 100 parts of alkoxy-terminated polysiloxane and 250 parts of epoxy-modified calcium carbonate, knead them in a kneader at 120°C, remove water under vacuum, cool to room temperature, add 12 parts of crosslinking agent, mix evenly, and degas under vacuum to obtain component B; the crosslinking agent is methyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in a mass ratio of 4:1; mix the two components evenly to obtain silicone sealant.

[0026] Comparative Example 2 (no calcium carbonate modification, otherwise the same as Example 1): S1: 40 parts of double-ended epoxy silicone oil and 13 parts of diisooctyl phosphoric acid were mixed and stirred under nitrogen protection and heated to 100°C. The mixture was stirred and reacted for 6 hours. The mixture was then distilled under reduced pressure to obtain phosphorus-containing silicone oil. S2: Mix 10 parts calcium carbonate and 9 parts double-ended epoxy silicone oil evenly to obtain a mixture of epoxy silicone oil and calcium carbonate; S3: Under nitrogen protection, 21 parts of phenyl dichloride phosphate were added to 100 parts of tetrahydrofuran and stirred in an ice bath at 0°C for 10 min. Then, 25 parts of triethylamine were added and stirred until homogeneous. The mixture of 12 parts of hydroxyethyl acrylate and 30 parts of tetrahydrofuran was added dropwise at a uniform rate over 2 h. After the addition was complete, the mixture was stirred for 6 h. Then, 12 parts of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide were added and stirred for another 12 h. The solvent was removed under reduced pressure to obtain the double-bonded flame retardant. S4: Add 10 parts of 2-thiol-benzoimidazole to 80 parts of ethanol, stir well, heat to reflux, and add 40 parts of a mixture of 2-bromoethylamine hydrobromide and 50 parts of ethanol dropwise at a uniform rate over 2 hours. Reflux for 24 hours, concentrate to obtain a white solid, add 400 parts of water and stir to dissolve, add sodium bicarbonate to adjust the pH to 8, add dichloromethane for extraction, combine the extracts and concentrate to obtain diamino-modified mercaptoimidazole; S5: 9 parts of double-bonded flame retardant and 5 parts of diamino-modified mercaptoimidazole were added to a mixed solution of 40 parts of tetrahydrofuran and 40 parts of ethanol, stirred evenly, 0.04 parts of photoinitiator 1173 were added, and the mixture was reacted under 15mW / cm² ultraviolet light for 10 min. The solvent was removed to obtain the flame retardant. S6: Take 100 parts of hydroxyl-terminated polymethylsiloxane, 55 parts of silicone oil composition, 45 parts of calcium carbonate, and 12 parts of flame retardant, mix them evenly, and degas under vacuum to obtain component A; the silicone oil composition is a mixture of phosphorus-containing silicone oil and amino silicone oil with a mass ratio of 1:1.5; take 100 parts of alkoxy-terminated polysiloxane, 250 parts of epoxy silicone oil and calcium carbonate mixture, knead them in a kneader at 120°C, remove water under vacuum, cool to room temperature, add 12 parts of crosslinking agent, mix evenly, and degas under vacuum to obtain component B; the crosslinking agent is a mixture of methyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane with a mass ratio of 4:1; mix the two components evenly to obtain silicone sealant.

[0027] Comparative Example 3 (the ratio of phosphorus-containing silicone oil and amino silicone oil was changed, and the rest was the same as in Example 1): S1: 40 parts of double-ended epoxy silicone oil and 13 parts of diisooctyl phosphoric acid were mixed and stirred under nitrogen protection and heated to 100°C. The mixture was stirred and reacted for 6 hours. The mixture was then distilled under reduced pressure to obtain phosphorus-containing silicone oil. S2: Add 0.5 parts of aminosilane coupling agent to a mixed solution of ethanol and water, adjust the pH to 5, stir for 2 minutes, heat to 60°C, add 12 parts of calcium carbonate, keep warm and stir for 5 hours, filter, wash, and dry to obtain amino-modified calcium carbonate; take 10 parts of amino-modified calcium carbonate and add it to 150 parts of xylene, add 9 parts of double-ended epoxy silicone oil, stir evenly, heat to 80°C, keep warm and stir for 3 hours, take the solid to obtain epoxy silicone oil modified calcium carbonate; S3: Under nitrogen protection, 21 parts of phenyl dichloride phosphate were added to 100 parts of tetrahydrofuran and stirred in an ice bath at 0°C for 10 min. Then, 25 parts of triethylamine were added and stirred until homogeneous. The mixture of 12 parts of hydroxyethyl acrylate and 30 parts of tetrahydrofuran was added dropwise at a uniform rate over 2 h. After the addition was complete, the mixture was stirred for 6 h. Then, 12 parts of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide were added and stirred for another 12 h. The solvent was removed under reduced pressure to obtain the double-bonded flame retardant. S4: Add 10 parts of 2-thiol-benzoimidazole to 80 parts of ethanol, stir well, heat to reflux, and add 40 parts of a mixture of 2-bromoethylamine hydrobromide and 50 parts of ethanol dropwise at a uniform rate over 2 hours. Reflux for 24 hours, concentrate to obtain a white solid, add 400 parts of water and stir to dissolve, add sodium bicarbonate to adjust the pH to 8, add dichloromethane for extraction, combine the extracts and concentrate to obtain diamino-modified mercaptoimidazole; S5: 9 parts of double-bonded flame retardant and 5 parts of diamino-modified mercaptoimidazole were added to a mixed solution of 40 parts of tetrahydrofuran and 40 parts of ethanol, stirred evenly, 0.04 parts of photoinitiator 1173 were added, and the mixture was reacted under 15mW / cm² ultraviolet light for 10 min. The solvent was removed to obtain the flame retardant. S6: Take 100 parts of hydroxyl-terminated polymethylsiloxane, 55 parts of silicone oil composition, 45 parts of amino-modified calcium carbonate, and 12 parts of flame retardant, mix them evenly, and degas under vacuum to obtain component A; the silicone oil composition is a phosphorus-containing silicone oil and amino silicone oil in a mass ratio of 2:1; take 100 parts of alkoxy-terminated polysiloxane and 250 parts of epoxy-modified calcium carbonate, knead them in a kneader at 120°C, remove water under vacuum, cool to room temperature, add 12 parts of crosslinking agent, mix evenly, and degas under vacuum to obtain component B; the crosslinking agent is methyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane in a mass ratio of 4:1; mix the two components evenly to obtain silicone sealant.

[0028] Comparative Example 4 (the crosslinking agent used was only methyltrimethoxysilane, and the rest was the same as in Example 1): S1: 40 parts of double-ended epoxy silicone oil and 13 parts of diisooctyl phosphoric acid were mixed and stirred under nitrogen protection and heated to 100°C. The mixture was stirred and reacted for 6 hours. The mixture was then distilled under reduced pressure to obtain phosphorus-containing silicone oil. S2: Add 0.5 parts of aminosilane coupling agent to a mixed solution of ethanol and water, adjust the pH to 5, stir for 2 minutes, heat to 60°C, add 12 parts of calcium carbonate, keep warm and stir for 5 hours, filter, wash, and dry to obtain amino-modified calcium carbonate; take 10 parts of amino-modified calcium carbonate and add it to 150 parts of xylene, add 9 parts of double-ended epoxy silicone oil, stir evenly, heat to 80°C, keep warm and stir for 3 hours, take the solid to obtain epoxy silicone oil modified calcium carbonate; S3: Under nitrogen protection, 21 parts of phenyl dichloride phosphate were added to 100 parts of tetrahydrofuran and stirred in an ice bath at 0°C for 10 min. Then, 25 parts of triethylamine were added and stirred until homogeneous. The mixture of 12 parts of hydroxyethyl acrylate and 30 parts of tetrahydrofuran was added dropwise at a uniform rate over 2 h. After the addition was complete, the mixture was stirred for 6 h. Then, 12 parts of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide were added and stirred for another 12 h. The solvent was removed under reduced pressure to obtain the double-bonded flame retardant. S4: Add 10 parts of 2-thiol-benzoimidazole to 80 parts of ethanol, stir well, heat to reflux, and add 40 parts of a mixture of 2-bromoethylamine hydrobromide and 50 parts of ethanol dropwise at a uniform rate over 2 hours. Reflux for 24 hours, concentrate to obtain a white solid, add 400 parts of water and stir to dissolve, add sodium bicarbonate to adjust the pH to 8, add dichloromethane for extraction, combine the extracts and concentrate to obtain diamino-modified mercaptoimidazole; S5: 9 parts of double-bonded flame retardant and 5 parts of diamino-modified mercaptoimidazole were added to a mixed solution of 40 parts of tetrahydrofuran and 40 parts of ethanol, stirred evenly, 0.04 parts of photoinitiator 1173 were added, and the mixture was reacted under 15mW / cm² ultraviolet light for 10 min. The solvent was removed to obtain the flame retardant. S6: Take 100 parts of hydroxyl-terminated polymethylsiloxane, 55 parts of silicone oil composition, 45 parts of amino-modified calcium carbonate, and 12 parts of flame retardant, mix them evenly, and degas under vacuum to obtain component A; the silicone oil composition is a phosphorus-containing silicone oil and amino silicone oil with a mass ratio of 1:1.5; take 100 parts of alkoxy-terminated polysiloxane and 250 parts of epoxy-modified calcium carbonate, knead them in a kneader at 120°C, remove water under vacuum, cool to room temperature, add 12 parts of crosslinking agent, mix evenly, and degas under vacuum to obtain component B; the crosslinking agent is methyltrimethoxysilane; mix the two components evenly to obtain silicone sealant.

[0029] Performance test 1: Take the A component and B component prepared in Examples 1-3 and Comparative Examples 1-4, mix them evenly, and cure them for 14 days at 25℃ and 50% relative humidity to obtain samples; (1) Prepare type 1 specimens according to GB / T528-2009 and test tensile strength and elongation at break; (2) According to GB / T9535-1998, test tensile strength for 1000h at 85℃ and 85% relative humidity and calculate the reduction rate; (3) According to GB / T2406.2-2009, test oxygen index; see Table 1 for details; Table 1:

[0030] Comparative Example 1, which used 2-thiol-benzoimidazole instead of diamino-modified mercaptoimidazole, and Comparative Example 2, which did not modify calcium carbonate, both resulted in decreased compatibility and performance. Comparative Example 3, which changed the ratio of phosphorus-containing silicone oil and amino silicone oil, and Comparative Example 4, which used only methyltrimethoxysilane as the crosslinking agent, affected the overall crosslinking network and resulted in decreased performance. In summary, the silicone sealant prepared by this method exhibits excellent mechanical properties, good resistance to damp heat, and good flame retardancy.

[0031] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An application of an alkoxy-terminated polysiloxane, characterized in that: Using alkoxy-terminated polysiloxanes in silicone sealants; The silicone sealant comprises the following raw materials, in parts by weight: 100-120 parts alkoxy-terminated polysiloxane, 200-260 parts silicone oil modified filler, 10-15 parts crosslinking agent; 50-60 parts silicone oil composition, 40-50 parts amino-modified filler, 10-15 parts flame retardant, and 100-120 parts hydroxyl-terminated polysiloxane; The silicone oil composition is a phosphorus-containing silicone oil or an amino silicone oil in a mass ratio of 1:(1~1.5); The silicone oil modified filler is an amino-modified filler modified with epoxy silicone oil. Its preparation includes the following steps: amino-modified filler is added to xylene and stirred until homogeneous; then, double-ended epoxy silicone oil is added and stirred until homogeneous; the temperature is raised to 70-80℃, and the mixture is kept at this temperature and stirred for 2-3 hours. The solid is then collected to obtain epoxy silicone oil modified calcium carbonate. The silicone oil modified filler comprises the following raw materials, by mass: 10-15 parts amino-modified filler and 5-9 parts double-ended epoxy silicone oil. The preparation of the flame retardant includes the following steps: S1: Under nitrogen protection, phenyl dichloride phosphate is added to tetrahydrofuran and stirred evenly under ice bath conditions. Triethylamine is added and stirring is maintained. The tetrahydrofuran mixture of hydroxyethyl acrylate is added dropwise at a uniform rate over 2-3 hours. After the addition is complete, the mixture is stirred for 4-6 hours. 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide is added and stirring is continued for 10-12 hours. The solvent is removed under reduced pressure to obtain the double-bonded flame retardant. S2: Add 2-thiol-benzoimidazole to ethanol and stir until homogeneous. Heat to reflux and add 2-bromoethylamine hydrobromide in ethanol at a uniform rate over 2-3 hours. Reflux for 24-30 hours and concentrate to obtain a white solid. Add water and stir to dissolve. Adjust the pH to 7-8 with sodium bicarbonate and extract to obtain diamino-modified mercaptoimidazole. S3: Add the double-bonded flame retardant and diamino-modified mercaptoimidazole to a mixed solution of tetrahydrofuran and ethanol and stir until homogeneous. Add the photoinitiator and react under ultraviolet light for 5-10 minutes. Remove the solvent to obtain the flame retardant.

2. The application of an alkoxy-terminated polysiloxane according to claim 1, characterized in that: The method for preparing the alkoxy-terminated polysiloxane includes the following steps: under nitrogen protection, the divinyl-terminated polydimethylsiloxane and platinum catalyst are mixed evenly and kept at 40~50℃ for 0.5~1h, hydrogen-containing alkoxysilane is added, and the reaction is kept at 100~120℃ for 3~6h to remove low molecular weight products and obtain alkoxy-terminated polysiloxane.

3. The application of an alkoxy-terminated polysiloxane according to claim 2, characterized in that: The alkoxy-terminated polysiloxane comprises the following raw materials, by mass parts: 180-220 parts of divinyl-terminated polydimethylsiloxane, 0.01-0.05 parts of platinum catalyst, and 0.5-2 parts of hydrogen-containing alkoxysilane.

4. The application of an alkoxy-terminated polysiloxane according to claim 1, characterized in that: The preparation of the phosphorus-containing silicone oil includes the following steps: mixing double-ended epoxy silicone oil and diisooctyl phosphoric acid under nitrogen protection, stirring and heating to 95~100℃, stirring and reacting for 6~8h, and distilling under reduced pressure to obtain phosphorus-containing silicone oil; the molar ratio of the double-ended epoxy silicone oil and diisooctyl phosphoric acid is 1:(2~3).

5. The application of an alkoxy-terminated polysiloxane according to claim 1, characterized in that: The preparation of the amino-modified filler includes the following steps: adding an aminosilane coupling agent to a mixed solution of ethanol and water, adjusting the pH to 4-5, stirring for 2-5 minutes, heating to 60-70°C, adding the filler, keeping warm and stirring for 3-5 hours, filtering, washing, and drying to obtain the amino-modified filler; the amino-modified filler includes the following raw materials, by mass parts: 0.5-1 parts aminosilane coupling agent, 10-15 parts filler.

6. The application of an alkoxy-terminated polysiloxane according to claim 1, characterized in that: The crosslinking agent is methyltrimethoxysilane or γ-(2,3-epoxypropoxy)propyltrimethoxysilane in a mass ratio of (3~5):

1.

7. The application of an alkoxy-terminated polysiloxane according to claim 1, characterized in that: The double-bonded flame retardant comprises the following raw materials, in parts by mass: 20-25 parts phenyl phosphate dichloride, 20-25 parts triethylamine, 10-14 parts hydroxyethyl acrylate, and 10-12 parts 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide. The diamino-modified mercaptoimidazole comprises the following raw materials, in parts by mass: 10-12 parts 2-thiol-benzoimidazole, 35-45 parts 2-bromoethylamine hydrobromide; The flame retardant comprises the following raw materials, in parts by weight: 9-10 parts of double-bonded flame retardant, 4-5 parts of diamino-modified mercaptoimidazole, and 0.03-0.05 parts of photoinitiator.

8. The application of an alkoxy-terminated polysiloxane according to claim 1, characterized in that: The preparation of the silicone sealant includes the following steps: taking hydroxyl-terminated polysiloxane, silicone oil composition, amino-modified filler, and flame retardant, mixing them evenly, and degassing under vacuum to obtain component A; taking alkoxy-terminated polysiloxane and silicone oil-modified filler, kneading them in a kneader, dehydrating them under vacuum, cooling them to room temperature, adding a crosslinking agent, mixing them evenly, and degassing under vacuum to obtain component B; mixing the two components evenly to obtain the silicone sealant.

Images