One-component transparent silicone sealant and method for producing the same

Abstract

The application discloses a single-component transparent silicone sealant and a preparation method thereof. The single-component transparent silicone sealant is prepared from alpha, omega-dihydroxyl polydimethylsiloxane, a hydroxyl-terminated phenyl-modified resin, heat-resistant fillers, a hydroxyl scavenger, a crosslinking agent, a coupling agent and a catalyst. The crosslinking agent is composed of butanone oxime silane and siloxane oligomers. The hydroxyl-terminated phenyl-modified resin is modified from methyl-terminated phenyl MQ resin. The MQ ratio of the methyl-terminated phenyl MQ resin is 0.5-1, and the phenyl content is 5%-30%. The silicone sealant can maintain high transparency, and has good heat resistance and curing performance. The silicone sealant is a single-component system, and can be applied to the market. After being applied to the market, the silicone sealant can be constructed by using simple glue coating equipment, and the construction cost of enterprises is reduced.

Description

Technical Field

[0001] This invention belongs to the field of organosilicon polymer materials technology, and more specifically, this invention relates to a single-component transparent silicone sealant and its preparation method. Background Technology

[0002] Silicone sealants absorb moisture from the air and cross-link to cure into high-performance polymers. They are widely used for bonding and sealing in photovoltaics, construction, electronics, rail transportation, and the automotive industry, and are an indispensable polymer material in today's society.

[0003] Based on appearance, silicone sealants can be divided into transparent and non-transparent systems. Transparent sealants are required for sealing some household appliances to ensure the overall aesthetic appeal of the equipment. However, in high-temperature environments, such as ovens and microwave ovens, non-transparent single-component sealants filled with heat-resistant powders are often necessary to ensure the sealant's temperature resistance. These sealants have low light transmittance, affecting the overall aesthetics. Furthermore, the slow curing rate of these sealants impacts production line efficiency. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a one-component silicone sealant that combines transparency and high temperature resistance with a fast curing speed.

[0005] The technical solutions for achieving the above-mentioned objectives include the following.

[0006] In a first aspect, the present invention provides the above-mentioned one-component transparent silicone sealant, which is prepared from the following raw materials in parts by weight:

[0007] 100 parts of α,ω-dihydroxypolydimethylsiloxane

[0008] 5 to 50 parts of hydroxyl-terminated phenyl modified resin

[0009] 5 to 15 parts of heat-resistant filler

[0010] Hydroxyl scavenger 0.5 to 2 parts

[0011] 5 to 15 parts of crosslinking agent

[0012] 0.5 to 1.5 parts coupling agent

[0013] Catalyst 0.05 to 0.15 parts

[0014] The crosslinking agent is composed of butanone oxime silane and siloxane oligomers in a weight ratio of 3 to 5:1; the hydroxyl-terminated phenyl modified resin is obtained by modifying methyl-terminated phenyl MQ resin, wherein the MQ ratio of the methyl-terminated phenyl MQ resin is 0.5 to 1 and the phenyl content is 5% to 30%.

[0015] A second aspect of the present invention provides a method for preparing the above-mentioned one-component transparent silicone sealant, comprising the following steps:

[0016] (1) Add α,ω-dihydroxy polydimethylsiloxane and hydroxyl-terminated phenyl modified resin to a planetary machine and stir for 20 min to 40 min under a vacuum of -0.095 MPa to -0.085 MPa;

[0017] (2) Add butanone oxime silane and siloxane oligomer to the planetary machine in sequence and stir for 30 min to 50 min under a vacuum of -0.095 MPa to -0.085 MPa;

[0018] (3) Add the heat-resistant filler and hydroxyl scavenger to the planetary machine in sequence, and stir for 30 min to 50 min under a vacuum of -0.095 MPa to -0.085 MPa;

[0019] (4) Add the coupling agent and catalyst to the planetary machine in sequence, stir for 30 min to 50 min under a vacuum of -0.095Mpa to -0.085Mpa, and then cool and discharge the material.

[0020] In this invention, MQ silicone resin with phenyl groups is modified to introduce active hydroxyl groups, resulting in hydroxyl-terminated phenyl-modified resin. This resin is then used as a base adhesive together with α,ω-dihydroxy polydimethylsiloxane, and crosslinking agents are compounded with butanone oxime silane and siloxane oligomers. Other components such as heat-resistant fillers, hydroxyl scavengers, coupling agents, and catalysts are also incorporated. The resulting silicone sealant maintains high transparency while also exhibiting good temperature resistance and curing performance. It has high tensile strength and elongation at break at room temperature, fast curing speed, and retains over 90% of its mechanical properties after baking at 260°C for 7 days, while still maintaining adhesion to the substrate.

[0021] The silicone sealant of this invention is a single-component system. After being applied to the market, it can be applied with only simple adhesive application equipment, thus reducing the construction costs for enterprises. Detailed Implementation

[0022] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0024] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the examples are commercially available products.

[0025] In some embodiments of the present invention, a one-component transparent silicone sealant is disclosed, prepared from the following raw materials in parts by weight:

[0026] 100 parts of α,ω-dihydroxypolydimethylsiloxane

[0027] 5 to 50 parts of hydroxyl-terminated phenyl modified resin

[0028] 5 to 15 parts of heat-resistant filler

[0029] Hydroxyl scavenger 0.5 to 2 parts

[0030] 5 to 15 parts of crosslinking agent

[0031] 0.5 to 1.5 parts coupling agent

[0032] Catalyst 0.05 to 0.15 parts

[0033] The crosslinking agent is composed of butanone oxime silane and siloxane oligomers in a weight ratio of 3 to 5:1.

[0034] The hydroxyl-terminated phenyl modified resin is obtained by modifying methyl-terminated phenyl MQ resin, wherein the methyl-terminated phenyl MQ resin has an MQ ratio of 0.5 to 1 and a phenyl content of 5% to 30%.

[0035] In one embodiment, the methyl-terminated phenyl MQ resin has an MQ ratio of 0.6 to 0.7 and a phenyl content of 20% to 30%.

[0036] In one embodiment, the molecular weight of the methyl-terminated phenyl MQ resin is 2000-5000.

[0037] In one embodiment, the hydroxyl content of the hydroxyl-terminated phenyl modified resin is 0.7% to 3%.

[0038] In one embodiment, the hydroxyl content of the hydroxyl-terminated phenyl modified resin is 2% to 2.5%.

[0039] In one embodiment, the molecular weight of the hydroxyl-terminated phenyl modified resin is 2000-5000.

[0040] In one embodiment, the hydroxyl-terminated phenyl-modified resin is prepared by the following steps:

[0041] (1) Dissolve methyl-terminated phenyl MQ resin in anhydrous toluene, introduce chlorine gas, and then add anhydrous aluminum trichloride. Stir at 0-5℃ for 1 h to 2 h; the weight ratio of methyl-terminated phenyl MQ resin, anhydrous aluminum trichloride and chlorine gas is 100:(0.5~2):(1.5~6.3).

[0042] (2) Pour the reaction solution from step (1) into water at 0-5℃ and separate to obtain the organic phase;

[0043] (3) Pour the organic phase into an aqueous solution of sodium bicarbonate, separate the liquid to obtain the organic layer; remove the solvent to obtain the final product.

[0044] In one embodiment, the weight ratio of the methyl-terminated phenyl MQ resin, anhydrous aluminum trichloride, and chlorine in step (1) is 100:(1~1.2):(4.5~5).

[0045] In one embodiment, the crosslinking agent is composed of butanone oxime silane and siloxane oligomers in a weight ratio of 3.5 to 4.5:1.

[0046] In one embodiment, the butanone oxime silane is one or more of methyl tributanone oxime silane, vinyl tributanone oxime silane, phenyl tributanone oxime silane, methyl vinyl dibutanone oxime silane, tetrabutanone oxime silane, and methyl triacetone oxime silane.

[0047] In one embodiment, the butanone oxime silane is one or two of methyl tributanone oxime silane, vinyl tributanone oxime silane, phenyl tributanone oxime silane, tetrabutanone oxime silane, and methyl triacetone oxime silane.

[0048] In one embodiment, the siloxane oligomer is polymethyltriethoxysilane with a degree of polymerization of 2 to 8.

[0049] In one embodiment, the degree of polymerization of the polymethyltriethoxysilane is 2 to 4.

[0050] In one embodiment, the viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25°C is 500cp~50000cp.

[0051] In one embodiment, the heat-resistant filler is silica or glass powder.

[0052] In one embodiment, the hydroxyl scavenger is hexamethyldisilazane.

[0053] In one embodiment, the coupling agent is 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropylmethyldiethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, 3-diethylenetriaminepropyltrimethoxysilane, N-(2-dimethylaminoethyl)-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, bis(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, bis(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(2-aminoethyl)-3-aminoethyl ... One or more of the following: (3-triethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)amine, 3-diethylenetriaminepropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, 3-glycidyletheroxypropyltriethoxysilane, 3-glycidyletheroxypropyltrimethoxysilane, 3-glycidyletheroxypropylmethyldimethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0054] In one embodiment, the catalyst is one or more of dibutyltin diacetate, dimethyltin hydroxyacetate, dimethyltin dinephrate, dibutyltin diisooctylmaleate, dibutyltin dilaurate, and dioctyltin dilaurate.

[0055] In other embodiments of the present invention, a method for preparing a one-component transparent silicone sealant is disclosed, comprising the following steps:

[0056] (1) Add α,ω-dihydroxy polydimethylsiloxane and hydroxyl-terminated phenyl modified resin to a planetary machine and stir for 20 min to 40 min under a vacuum of -0.095 MPa to -0.085 MPa;

[0057] (2) Add butanone oxime silane and siloxane oligomer to the planetary machine in sequence and stir for 30 min to 50 min under a vacuum of -0.095 MPa to -0.085 MPa;

[0058] (3) Add the heat-resistant filler and hydroxyl scavenger to the planetary machine in sequence, and stir for 30 min to 50 min under a vacuum of -0.095 MPa to -0.085 MPa;

[0059] (4) Add the coupling agent and catalyst to the planetary machine in sequence, stir for 30 min to 50 min under a vacuum of -0.095Mpa to -0.085Mpa, and then cool and discharge the material.

[0060] The present invention will be described in detail below with reference to specific embodiments.

[0061] Example 1

[0062] This embodiment provides a one-component transparent silicone sealant, prepared from the following raw materials in parts by weight:

[0063] 100 parts of α,ω-dihydroxypolydimethylsiloxane (base gel, 20000cp)

[0064] Hydroxyl-terminated phenyl modified resin (base resin, hydroxyl content 2.3%) 25 parts

[0065] 10 parts of silica (heat-resistant filler)

[0066] Hexamethyldisilazane (hydroxyl scavenger) 1 part

[0067] Vinyltributylone oxime silane (crosslinking agent) 2 parts

[0068] Tetrabutylone oxime silane (crosslinking agent) 6 parts

[0069] Polymethyltriethoxysilane (crosslinking agent, degree of polymerization 4) 2 parts

[0070] Bis(3-trimethoxysilylpropyl)amine (coupling agent) 1.5 parts

[0071] 0.75 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane (coupling agent)

[0072] Dibutyltin dilaurate (catalyst) 0.1 parts

[0073] The hydroxyl-terminated phenyl modified resin was prepared by the following method: 100 parts of a commercially available, dried methyl-terminated phenyl MQ resin (MQ resin with an MQ ratio of 0.7, a phenyl content of 20%, and a molecular weight of 2700) was dissolved in 150 parts of anhydrous toluene to prepare a solution. The solution was then poured into a glass reaction flask, and 4.6 parts of chlorine gas and 1 part of anhydrous aluminum trichloride were introduced. The mixture was rapidly stirred for 1 hour in an ice bath at 2°C. After the reaction, the reaction solution was poured into ice water to decompose excess chlorine gas and aluminum trichloride, and the organic phase was separated. The separated organic phase was slowly poured into an 8% sodium bicarbonate aqueous solution for hydrolysis, and the organic layer was obtained by separation. Anhydrous magnesium sulfate was added to the organic layer for drying, and excess solvent was removed by rotary evaporation. Finally, chemical titration was performed using the acetylation method to confirm the hydroxyl content of the methyl-terminated phenyl modified resin, yielding a hydroxyl content of 2.3%.

[0074] The preparation method of the single-component transparent silicone sealant described in this embodiment is as follows:

[0075] (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 20000cp and 25 parts of hydroxyl-terminated phenyl modified resin with a hydroxyl content of 2.3% were added to a planetary machine and stirred for 25 min under a vacuum of -0.090 MPa.

[0076] (2) Add 2 parts of vinyltributylone oxime silane, 6 parts of tetrabutylone oxime silane and 2 parts of polymethyltriethoxysilane with a degree of polymerization of 4 to the planetary machine in sequence, and stir for 40 min under a vacuum of -0.090 MPa.

[0077] (3) Add 10 parts of silica and 1 part of hexamethyldisilazane to the planetary machine in sequence, and stir for 40 min under a vacuum of -0.090 MPa.

[0078] (4) 1.5 parts of bis(3-trimethoxysilylpropyl)amine, 0.75 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.1 parts of dibutyltin dilaurate were added to the planetary machine in sequence and stirred for 35 min under a vacuum of -0.090 MPa.

[0079] (5) After cooling, discharge the material and seal it for storage.

[0080] Example 2

[0081] This embodiment provides a one-component transparent silicone sealant, prepared from the following raw materials in parts by weight:

[0082] 100 parts of α,ω-dihydroxypolydimethylsiloxane (base gel, 15000cp)

[0083] Hydroxyl-terminated phenyl modified resin (base resin, hydroxyl content 2.5%) 26 parts

[0084] 11 parts glass powder (heat-resistant filler)

[0085] Hexamethyldisilazane (hydroxyl scavenger) 1.2 parts

[0086] 2 parts of methyl tributanone oxime silane (crosslinking agent)

[0087] Tetrabutylone oxime silane (crosslinking agent) 6 parts

[0088] Polymethyltriethoxysilane (crosslinking agent, degree of polymerization 4) 2 parts

[0089] 3-Aminopropylmethyldimethoxysilane (coupling agent) 1.65 parts

[0090] 0.8 parts of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (coupling agent)

[0091] Dibutyltin diacetate (catalyst) 0.15 parts

[0092] The hydroxyl-terminated phenyl modified resin was prepared by the following method: 100 parts of a commercially available, dried methyl-terminated phenyl MQ resin (MQ resin with an MQ ratio of 0.6, a phenyl content of 23%, and a molecular weight of 3000) was dissolved in 150 parts of anhydrous toluene to prepare a solution. The solution was then poured into a glass reaction flask, 5 parts of chlorine gas were introduced, and 1.2 parts of anhydrous aluminum trichloride were added. The mixture was rapidly stirred for 1.2 hours under an ice bath at 2°C. After the reaction, the reaction solution was poured into ice water to decompose excess chlorine gas and aluminum trichloride, and the organic phase was separated. The separated organic phase was slowly poured into an 8% sodium bicarbonate aqueous solution for hydrolysis, and the organic layer was obtained by separation. Anhydrous magnesium sulfate was added to the organic layer for drying, and excess solvent was removed by rotary evaporation. Finally, chemical titration was performed using the acetylation method to confirm the hydroxyl content of the phenyl modified resin, yielding a hydroxyl-terminated phenyl modified resin with a hydroxyl content of 2.5%.

[0093] The preparation method of the single-component transparent silicone sealant described in this embodiment is as follows:

[0094] (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 15000cp and 26 parts of hydroxyl-terminated phenyl modified resin with a hydroxyl content of 2.5% were added to a planetary machine and stirred for 30 min under a vacuum of -0.090 MPa.

[0095] (2) Add 2 parts of methyltributylone oxime silane, 6 parts of tetrabutylone oxime silane and 2 parts of polymethyltriethoxysilane with a degree of polymerization of 4 to the planetary machine in sequence, and stir for 40 min under a vacuum of -0.090 MPa.

[0096] (3) Add 11 parts of glass powder and 1.2 parts of hexamethyldisilazane to the planetary machine in sequence, and stir for 40 min under a vacuum of -0.090 MPa.

[0097] (4) 1.65 parts of 3-aminopropylmethyldimethoxysilane, 0.8 parts of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane and 0.15 parts of dibutyltin diacetate were added to the planetary machine in sequence and stirred for 35 min under a vacuum of -0.090 MPa.

[0098] (5) After cooling, discharge the material and seal it for storage.

[0099] Example 3

[0100] This embodiment provides a one-component transparent silicone sealant, prepared from the following raw materials in parts by weight:

[0101] 100 parts of α,ω-dihydroxypolydimethylsiloxane (base gel, 12000cp)

[0102] Hydroxyl-terminated phenyl modified resin (base resin, hydroxyl content 2.4%) 28 parts

[0103] 10 parts of silica (heat-resistant filler)

[0104] Hexamethyldisilazane (hydroxyl scavenger) 1.1 parts

[0105] Vinyltributylone oxime silane (crosslinking agent) 2 parts

[0106] 6 parts of phenyltributanone oxime silane (crosslinking agent)

[0107] Polymethyltriethoxysilane (crosslinking agent, degree of polymerization 2) 2 parts

[0108] Bis(3-trimethoxysilylpropyl)amine (coupling agent) 1.65 parts

[0109] N-2-Aminoethyl-3-aminopropylmethyldiethoxysilane (coupling agent) 0.8 parts

[0110] Hydroxydimethyltin (catalyst) 0.15 parts

[0111] The hydroxyl-terminated phenyl modified resin was prepared by the following method: 100 parts of a commercially available, dried methyl-terminated phenyl MQ resin (MQ resin with an MQ ratio of 0.6, a phenyl content of 22%, and a molecular weight of 2900) was dissolved in 150 parts of anhydrous toluene to prepare a solution. The solution was then poured into a glass reaction flask, and 4.8 parts of chlorine gas and 1.1 parts of anhydrous aluminum trichloride were introduced. The mixture was rapidly stirred for 1.5 hours in an ice bath at 2°C. After the reaction, the reaction solution was poured into ice water to decompose excess chlorine gas and aluminum trichloride, and the organic phase was separated. The separated organic phase was slowly poured into an 8% sodium bicarbonate aqueous solution for hydrolysis, and the organic layer was obtained by separation. Anhydrous magnesium sulfate was added to the organic layer for drying, and excess solvent was removed by rotary evaporation. Finally, chemical titration was performed using the acetylation method to confirm the hydroxyl content of the methyl-terminated phenyl modified resin, yielding a hydroxyl content of 2.4%.

[0112] The preparation method of the single-component transparent silicone sealant described in this embodiment is as follows:

[0113] (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 12000cp and 28 parts of hydroxyl-terminated phenyl modified resin with a hydroxyl content of 2.4% were added to a planetary machine and stirred for 35 min under a vacuum of -0.090 MPa.

[0114] (2) Add 2 parts of vinyltributylone oxime silane, 6 parts of phenyltributylone oxime silane and 2 parts of polymethyltriethoxysilane with a degree of polymerization of 2 to the planetary machine in sequence, and stir for 35 min under a vacuum of -0.090 MPa.

[0115] (3) Add 10 parts of silica and 1.1 parts of hexamethyldisilazane to the planetary machine in sequence, and stir for 40 min under a vacuum of -0.090 MPa.

[0116] (4) 1.65 parts of bis(3-trimethoxysilylpropyl)amine, 0.8 parts of N-2-aminoethyl-3-aminopropylmethyldiethoxysilane and 0.15 parts of hydroxydimethyltin were added to the planetary machine in sequence and stirred for 35 min under a vacuum of -0.090 MPa.

[0117] (5) After cooling, discharge the material and seal it for storage.

[0118] Example 4

[0119] This embodiment provides a one-component transparent silicone sealant, prepared from the following raw materials in parts by weight:

[0120] 100 parts of α,ω-dihydroxypolydimethylsiloxane (base gel, 20000cp)

[0121] Hydroxyl-terminated phenyl modified resin (base resin, hydroxyl content 2.3%) 25 parts

[0122] 10 parts of silica (heat-resistant filler)

[0123] Hexamethyldisilazane (hydroxyl scavenger) 1 part

[0124] Vinyltributylone oxime silane (crosslinking agent) 2 parts

[0125] Tetrabutylone oxime silane (crosslinking agent) 6 parts

[0126] Polymethyltriethoxysilane (crosslinking agent, degree of polymerization 4) 2 parts

[0127] Bis(3-trimethoxysilylpropyl)amine (coupling agent) 1.5 parts

[0128] 0.75 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane (coupling agent)

[0129] Dibutyltin dilaurate (catalyst) 0.15 parts

[0130] The hydroxyl-terminated phenyl modified resin was prepared by the following method: 100 parts of a commercially available, dried methyl-terminated phenyl MQ resin (MQ resin with an MQ ratio of 0.7, a phenyl content of 26%, and a molecular weight of 2800) was dissolved in 150 parts of anhydrous toluene to prepare a solution. The solution was then poured into a glass reaction flask, and 4.6 parts of chlorine gas and 1 part of anhydrous aluminum trichloride were introduced. The mixture was rapidly stirred for 1 hour in an ice bath at 2°C. After the reaction, the reaction solution was poured into ice water to decompose excess chlorine gas and aluminum trichloride, and the organic phase was separated. The separated organic phase was slowly poured into an 8% sodium bicarbonate aqueous solution for hydrolysis, and the organic layer was obtained by separation. Anhydrous magnesium sulfate was added to the organic layer for drying, and excess solvent was removed by rotary evaporation. Finally, chemical titration was performed using the acetylation method to confirm the hydroxyl content of the methyl-terminated phenyl modified resin, yielding a hydroxyl content of 2.3%.

[0131] The preparation method of the single-component transparent silicone sealant described in this embodiment is as follows:

[0132] (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 20000cp and 25 parts of hydroxyl-terminated phenyl modified resin with a hydroxyl content of 2.3% were added to a planetary machine and stirred for 25 min under a vacuum of -0.090 MPa.

[0133] (2) Add 2 parts of vinyltributylone oxime silane, 6 parts of tetrabutylone oxime silane and 2 parts of polymethyltriethoxysilane with a degree of polymerization of 4 to the planetary machine in sequence, and stir for 40 min under a vacuum of -0.090 MPa.

[0134] (3) Add 10 parts of silica and 1 part of hexamethyldisilazane to the planetary machine in sequence, and stir for 40 min under a vacuum of -0.090 MPa.

[0135] (4) 1.5 parts of bis(3-trimethoxysilylpropyl)amine, 0.75 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.1 parts of dibutyltin dilaurate were added to the planetary machine in sequence and stirred for 35 min under a vacuum of -0.090 MPa.

[0136] (5) After cooling, discharge the material and seal it for storage.

[0137] Example 5

[0138] This embodiment provides a one-component transparent silicone sealant, prepared from the following raw materials in parts by weight:

[0139] 100 parts of α,ω-dihydroxypolydimethylsiloxane (base gel, 15000cp)

[0140] Hydroxyl-terminated phenyl modified resin (base resin, hydroxyl content 2.5%) 26 parts

[0141] 11 parts glass powder (heat-resistant filler)

[0142] Hexamethyldisilazane (hydroxyl scavenger) 1.2 parts

[0143] 2 parts of methyl tributanone oxime silane (crosslinking agent)

[0144] Tetrabutylone oxime silane (crosslinking agent) 6 parts

[0145] Polymethyltriethoxysilane (crosslinking agent, degree of polymerization 4) 4 parts

[0146] 3-Aminopropylmethyldimethoxysilane (coupling agent) 1.65 parts

[0147] 0.8 parts of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (coupling agent)

[0148] Dibutyltin diacetate (catalyst) 0.15 parts

[0149] The hydroxyl-terminated phenyl modified resin was prepared by the following method: 100 parts of a commercially available, dried methyl-terminated phenyl MQ resin (MQ resin with an MQ ratio of 0.6, a phenyl content of 23%, and a molecular weight of 3000) was dissolved in 150 parts of anhydrous toluene to prepare a solution. The solution was then poured into a glass reaction flask, 5 parts of chlorine gas were introduced, and 1.2 parts of anhydrous aluminum trichloride were added. The mixture was rapidly stirred for 1.2 hours under an ice bath at 2°C. After the reaction, the reaction solution was poured into ice water to decompose excess chlorine gas and aluminum trichloride, and the organic phase was separated. The separated organic phase was slowly poured into an 8% sodium bicarbonate aqueous solution for hydrolysis, and the organic layer was obtained by separation. Anhydrous magnesium sulfate was added to the organic layer for drying, and excess solvent was removed by rotary evaporation. Finally, chemical titration was performed using the acetylation method to confirm the hydroxyl content of the phenyl modified resin, yielding a hydroxyl-terminated phenyl modified resin with a hydroxyl content of 2.5%.

[0150] The preparation method of the single-component transparent silicone sealant described in this embodiment is as follows:

[0151] (1) 100 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 15000cp and 26 parts of hydroxyl-terminated phenyl modified resin with a hydroxyl content of 2.5% were added to a planetary machine and stirred for 30 min under a vacuum of -0.090 MPa.

[0152] (2) Add 2 parts of methyltributylone oxime silane, 6 parts of tetrabutylone oxime silane and 4 parts of polymethyltriethoxysilane with a degree of polymerization of 4 to the planetary machine in sequence, and stir for 40 min under a vacuum of -0.090 MPa.

[0153] (3) Add 11 parts of glass powder and 1.2 parts of hexamethyldisilazane to the planetary machine in sequence, and stir for 40 min under a vacuum of -0.090 MPa.

[0154] (4) 1.65 parts of 3-aminopropylmethyldimethoxysilane, 0.8 parts of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane and 0.15 parts of dibutyltin diacetate were added to the planetary machine in sequence and stirred for 35 min under a vacuum of -0.090 MPa.

[0155] (5) After cooling, discharge the material and seal it for storage.

[0156] Comparative Example 1

[0157] This comparative example provides a one-component transparent silicone sealant, prepared from the following raw materials in parts by weight:

[0158] 100 parts of α,ω-dihydroxypolydimethylsiloxane (base gel, 20000cp)

[0159] Hydroxyl-terminated phenyl modified resin (base resin, hydroxyl content 2.3%) 25 parts

[0160] 10 parts of silica (heat-resistant filler)

[0161] Hexamethyldisilazane (hydroxyl scavenger) 1 part

[0162] Vinyltributylone oxime silane (crosslinking agent) 2 parts

[0163] Tetrabutylone oxime silane (crosslinking agent) 8 parts

[0164] Bis(3-trimethoxysilylpropyl)amine (coupling agent) 1.5 parts

[0165] 0.75 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane (coupling agent)

[0166] Dibutyltin dilaurate (catalyst) 0.15 parts

[0167] The preparation method of the hydroxyl-terminated phenyl modified resin with a hydroxyl content of 2.3% is the same as in Example 1.

[0168] The preparation method of the silicone sealant is described in Example 1.

[0169] Comparative Example 2

[0170] This comparative example provides a one-component transparent silicone sealant, prepared from the following raw materials in parts by weight:

[0171] 100 parts of α,ω-dihydroxypolydimethylsiloxane (base gel, 15000cp)

[0172] Dimethyl silicone oil (plasticizer, 350 cp) 11 parts

[0173] 15 parts glass powder (heat-resistant filler)

[0174] Hexamethyldisilazane (hydroxyl scavenger) 1.2 parts

[0175] Vinyltributylone oxime silane (crosslinking agent) 2 parts

[0176] Tetrabutylone oxime silane (crosslinking agent) 6 parts

[0177] Polymethyltriethoxysilane (crosslinking agent, degree of polymerization 4) 2 parts

[0178] 3-Aminopropylmethyldimethoxysilane (coupling agent) 1.65 parts

[0179] 0.8 parts of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (coupling agent)

[0180] Dibutyltin diacetate (catalyst) 0.15 parts

[0181] The preparation method of the silicone sealant is described in Example 2.

[0182] Comparative Example 3

[0183] This comparative example provides a one-component transparent silicone sealant, prepared from the following raw materials in parts by weight:

[0184] 100 parts of α,ω-dihydroxypolydimethylsiloxane (base gel, 20000cp)

[0185] Hydroxyl-terminated phenyl modified resin (base resin, hydroxyl content 2.3%) 25 parts

[0186] 10 parts of silica (heat-resistant filler)

[0187] Hexamethyldisilazane (hydroxyl scavenger) 1 part

[0188] 4 parts of methyltrimethoxysilane (crosslinking agent)

[0189] Polymethyltriethoxysilane (crosslinking agent, degree of polymerization 4) 2 parts

[0190] Bis(3-trimethoxysilylpropyl)amine (coupling agent) 1.5 parts

[0191] 0.75 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane (coupling agent)

[0192] Di(ethyl acetoacetate) diisopropoxytitanium (catalyst) 5 parts

[0193] The preparation method of the hydroxyl-terminated phenyl modified resin with a hydroxyl content of 2.3% is the same as in Example 1.

[0194] The preparation method of the silicone sealant is described in Example 1.

[0195] The silicone sealants prepared in the above embodiments and comparative examples were subjected to comprehensive performance tests at room temperature. The silicone sealants prepared in the above embodiments and comparative examples were baked at 260°C for 7 days before comprehensive performance tests were conducted.

[0196] Tensile strength and elongation at break were tested according to the requirements for Type 1 specimens (non-standard thickness) in GB / T 528-2009; Shore A hardness was tested according to GB / T 531-2008; adhesion was tested according to Method 2 in Appendix D1.2 of GB 16776-2005; curing speed was tested according to Method 2 of GB / T 32369-2015; and light transmittance was tested according to the specifications in GB / T1699-2007.

[0197] The comprehensive performance test results of the silicone sealants in each embodiment and comparative example at room temperature are shown in Table 1. The comprehensive performance test results of the silicone sealants in each embodiment and comparative example after baking at 260℃ for 7 days are shown in Table 2.

[0198] Table 1

[0199]

[0200] Note: The bonding substrates are float glass, anodized aluminum, and 304 stainless steel. √ indicates 100% cohesive failure, × indicates 100% interfacial failure.

[0201] Table 2

[0202]

[0203] Note: The bonding substrates are float glass, anodized aluminum and 304 stainless steel. √ indicates 100% cohesive failure and × indicates 100% interfacial failure.

[0204] As shown in Tables 1 and 2, the single-component transparent silicone sealants prepared in Examples 1-5 exhibit very high light transmittance, excellent tensile strength, elongation at break, hardness, and adhesion at room temperature, and a high curing speed. After baking at 260℃ for 7 days, the retention rates of tensile strength and elongation at break are both above 90%, while hardness and adhesion are essentially unaffected. Furthermore, increasing the phenyl content in the hydroxyl-terminated phenyl-modified resin decreases the initial tensile strength and increases the elongation at break, but improves the retention rate of mechanical properties after high-temperature baking (Example 1 vs. Example 4).

[0205] Compared to Example 1, Comparative Example 1 used only oxime silanes as crosslinking agents in the preparation of the silicone sealant, without using siloxane oligomers. Its heat resistance was similar to that of the silicone sealant in Example 1, but its curing speed at room temperature was much slower than that of Example 1. Therefore, using a combination of oxime silanes and siloxane oligomers as crosslinking agents to prepare silicone sealants can satisfy both the requirements for heat resistance and rapid curing.

[0206] Compared to Example 2, Comparative Example 2, which used dimethyl silicone oil as a plasticizer instead of hydroxyl-terminated phenyl modified resin in the preparation of silicone sealant, exhibited significantly inferior mechanical properties at room temperature compared to the silicone sealant of Example 2. Furthermore, after baking at 260°C for 7 days, its mechanical properties and hardness decreased rapidly, and it also lost its adhesive properties. This indicates that combining hydroxyl-terminated phenyl modified resin with α,ω-dihydroxypolydimethylsiloxane can improve the mechanical properties and heat resistance of transparent adhesives.

[0207] Compared to Example 1, Comparative Example 3, in preparing the silicone sealant, replaced the oxime silane in the crosslinking agent with methyltrimethoxysilane, and the catalyst with bis(ethyl acetoacetate)diisopropoxytitanium. Comparative Example 3 was prepared using a traditional de-alcoholized sealant formulation, and its light transmittance was significantly reduced, failing to meet the transparency requirements. Its curing speed at room temperature was significantly lower than that of Example 1. Furthermore, after baking at 260°C for 7 days, its mechanical properties and hardness decreased rapidly, and it also lost its adhesive properties.

[0208] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above 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.

[0209] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A one-component transparent silicone sealant, characterized in that, It is prepared from the following raw materials in parts by weight: 100 parts of α,ω-dihydroxypolydimethylsiloxane 5 to 50 parts of hydroxyl-terminated phenyl modified resin 5 to 15 parts of heat-resistant filler Hydroxyl scavenger 0.5 to 2 parts 5 to 15 parts of crosslinking agent 0.5 to 1.5 parts coupling agent Catalyst 0.05 to 0.15 parts The crosslinking agent is composed of butanone oxime silane and siloxane oligomers in a weight ratio of 3 to 5:

1. The hydroxyl-terminated phenyl modified resin is obtained by modifying methyl-terminated phenyl MQ resin, wherein the methyl-terminated phenyl MQ resin has an MQ ratio of 0.5 to 1 and a phenyl content of 5% to 30%.

2. The single-component transparent silicone sealant according to claim 1, characterized in that, The hydroxyl content of the hydroxyl-terminated phenyl modified resin is 0.7% to 3%, preferably 2% to 2.5%; the molecular weight of the hydroxyl-terminated phenyl modified resin is 2000 to 5000.

3. The single-component transparent silicone sealant according to claim 1, characterized in that, The methyl-terminated phenyl MQ resin has an MQ ratio of 0.6 to 0.7 and a phenyl content of 20% to 30%; the molecular weight of the methyl-terminated phenyl MQ resin is 2000 to 5000.

4. The single-component transparent silicone sealant according to claim 1, characterized in that, The hydroxyl-terminated phenyl-modified resin is prepared by the following steps: (1) Dissolve methyl-terminated phenyl MQ resin in anhydrous toluene, pass chlorine gas through it, and then add anhydrous aluminum trichloride. Stir at 0-5℃ for 1 h to 2 h. The weight ratio of the methyl-terminated phenyl MQ resin, anhydrous aluminum trichloride and chlorine gas is 100:0.5~2:1.5~6.

3. (2) Pour the reaction solution from step (1) into water at 0-5℃ and separate to obtain the organic phase; (3) Pour the organic phase into an aqueous solution of sodium bicarbonate, separate the liquid to obtain the organic layer; remove the solvent to obtain the final product.

5. The single-component transparent silicone sealant according to claim 4, characterized in that, The weight ratio of methyl-terminated phenyl MQ resin, anhydrous aluminum trichloride and chlorine gas in step (1) is 100:1~1.2:4.5~5.

6. The single-component transparent silicone sealant according to claim 1, characterized in that, The crosslinking agent is composed of butanone oxime silane and siloxane oligomers in a weight ratio of 3.5~4.5:

1.

7. The single-component transparent silicone sealant according to claim 6, characterized in that, The methyl tartrate oxime silane is one or more of methyl tartrate oxime silane, vinyl tartrate oxime silane, phenyl tartrate oxime silane, methyl vinyl dibutyl oxime silane, tetrabutyl oxime silane, and methyl triacetone oxime silane; And / or, the siloxane oligomer is polymethyltriethoxysilane with a degree of polymerization of 2 to 8.

8. The single-component transparent silicone sealant according to claim 7, characterized in that, The butanone oxime silane is one or two of methyl tributanone oxime silane, vinyl tributanone oxime silane, phenyl tributanone oxime silane, tetrabutanone oxime silane, and methyl triacetone oxime silane; And / or, the siloxane oligomer is polymethyltriethoxysilane with a degree of polymerization of 2 to 4.

9. The one-component transparent silicone sealant according to any one of claims 1 to 8, characterized in that, The viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25°C is 500cp~50000cp; And / or, the heat-resistant filler is silica or glass powder; And / or, the hydroxyl scavenger is hexamethyldisilazane; And / or, the coupling agent is 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropylmethyldiethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, 3-diethylenetriaminepropyltrimethoxysilane, N-(2-dimethylaminoethyl)-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, bis( ... One or more of the following: bis(3-trimethoxysilylpropyl)amine, 3-diethylenetriaminepropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, 3-glycidyletheroxypropyltriethoxysilane, 3-glycidyletheroxypropyltrimethoxysilane, 3-glycidyletheroxypropylmethyldimethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; And / or, the catalyst is one or more of dibutyltin diacetate, dimethyltin hydroxyacetate, dimethyltin dinephrate, dibutyltin diisooctylmaleate, dibutyltin dilaurate, and dioctyltin dilaurate.

10. A method for preparing the single-component transparent silicone sealant according to any one of claims 1 to 9, characterized in that, Includes the following steps: (1) Add α,ω-dihydroxy polydimethylsiloxane and hydroxyl-terminated phenyl modified resin to a planetary machine and stir for 20 min to 40 min under a vacuum of -0.095 MPa to -0.085 MPa. (2) Add butanone oxime silane and siloxane oligomer to the planetary machine in sequence and stir for 30 min to 50 min under a vacuum of -0.095 MPa to -0.085 MPa; (3) Add the heat-resistant filler and hydroxyl scavenger to the planetary machine in sequence, and stir for 30 min to 50 min under a vacuum of -0.095 MPa to -0.085 MPa; (4) Add the coupling agent and catalyst to the planetary machine in sequence, stir for 30 min to 50 min under a vacuum of -0.095Mpa to -0.085Mpa, and then cool and discharge the material.

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