Post-crosslinking type silane coupling agent suitable for silicone adhesive, water-resistant ultraviolet-resistant silicone adhesive and application of water-resistant ultraviolet-resistant silicone adhesive

Abstract

The invention provides a post-crosslinking type silane coupling agent, a water-resistant ultraviolet-resistant silicone adhesive and application of the water-resistant ultraviolet-resistant silicone adhesive and belongs to the technical field of sealants, and the post-crosslinking type silane coupling agent suitable for the silicone adhesive is bis (diisopropyl ketoxime) dimethoxysilane. The water-resistant ultraviolet-resistant silicone adhesive is prepared from polysiloxane resin, polydimethylsiloxane, polyether modified silicone oil, an ethylenediamine tetraacetic acid chelating agent, color paste, reactive silicone oil, a first silane coupling agent, an organic tin catalyst and a post-crosslinking silane coupling agent.

Description

Technical Field

[0001] This invention belongs to the field of sealant technology, and particularly relates to a post-crosslinking silane coupling agent suitable for silicone sealants, a water-resistant and UV-resistant silicone sealant, and their applications. Background Technology

[0002] Conventional silicone structural adhesives are at risk of debonding or partial debonding under water-UV conditions. This manifests as surface cracking and bonding failure after water-UV irradiation, ultimately leading to the material failing to meet usage requirements. The root cause is the combination of high-temperature water (45±1℃) and strong ultraviolet radiation (broadband irradiance of 60±2 W / m² at 300nm~400nm). 2 When using the narrowband measurement method, the irradiance at the narrowband (340 nm) is (0.51 ± 0.02) W / (m²). 2 After aging for 1008 hours under UV light, the surface of the material is damaged by ultraviolet rays and cracks appear, losing its waterproof / hydrophobic ability. Water can more easily penetrate into the sealant. At high temperatures, the silicone structural adhesive undergoes hydrolysis, leading to a decrease in the material's basic mechanical and adhesive properties, resulting in adhesive failure. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a post-crosslinking silane coupling agent suitable for silicone sealants, a water-resistant and UV-resistant silicone sealant, and their applications, aiming to at least partially solve the above-mentioned technical problems. The technical solution provided by this invention is as follows.

[0004] As a first aspect of the present invention, a post-crosslinking silane coupling agent suitable for silicone sealants is provided, which is bis(diisopropyl ketone oxime)dimethoxysilane having the following structure:

[0005] ; where iPr is isopropyl.

[0006] As a second aspect of the present invention, a method for preparing a post-crosslinking silane coupling agent is provided, comprising: reacting triethylamine with diisopropyl ketone oxime and dimethyl dichlorosilane to obtain bis(diisopropyl ketone oxime)dimethoxysilane.

[0007] As a third aspect of the present invention, a water-resistant and UV-resistant silicone adhesive is provided, comprising: polysiloxane resin, polydimethylsiloxane, polyether-modified silicone oil, ethylenediaminetetraacetic acid chelating agent, color paste, reactive silicone oil, a first silane coupling agent, an organotin catalyst, and the aforementioned post-crosslinking silane coupling agent.

[0008] As a fourth aspect of the invention, the application of water-resistant and UV-resistant silicone sealant in building sealants is provided.

[0009] Based on the above technical solution, the post-crosslinking silane coupling agent and water-resistant and UV-resistant silicone sealant provided by the present invention have at least one of the following beneficial effects:

[0010] (1) In the technical solution of the present invention, the two large diisopropyl ketone oxime groups in the post-crosslinking silane coupling agent provide sufficient steric hindrance for the intermediate silicon atom, which can effectively prevent the catalyst in the silicone sealant from approaching, thus keeping it inert in the silicone sealant. After hydrolysis, the post-crosslinking silane coupling agent forms a bissilol molecule, which can act as a chain extender or crosslinking agent, and can recombine with the polymer chain (Si-OH) formed by the hydrolysis and breakage of the two water molecules, effectively reconnecting the broken chain, repairing the network structure, and restoring the mechanical properties of the silicone sealant. In addition, the method for preparing the post-crosslinking silane coupling agent of the present invention is relatively simple and highly reproducible.

[0011] (2) In the technical solution of the present invention, the synthesized post-crosslinking silane coupling agent is applied to the silicone sealant formulation. Through its steric hindrance effect, appropriate retained activity, and water-triggered re-crosslinking ability, the adhesive effect of the silicone sealant after immersion in water or contact with water is ensured. Furthermore, polyether-modified silicone oil is introduced into the silicone sealant formulation. It can migrate to the silicone sealant interface and form a durable hydrophobic protective layer. Combined with the aforementioned water-reactive post-crosslinking scheme, the adhesive performance of the silicone sealant after immersion in water can be improved. Detailed Implementation

[0012] Embodiments of the present invention will be described below; however, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the invention.

[0013] Conventional silicone structural adhesives are at risk of debonding or partial debonding under water-UV conditions, which manifests in the following ways: 1) Cracks appear on the surface of the silicone adhesive after water-UV irradiation; 2) After the cracks appear, the adhesive is prone to absorbing water, which leads to a decrease in the mechanical and adhesive properties of the material.

[0014] Specifically, in practical applications, after 1008 hours of aging under strong ultraviolet (UV) irradiation, cracks appeared on the surface of the silicone sealant. The reason for this is that while the high Si-O-Si bond energy in the silicone sealant can resist UV radiation, the plasticizers, resin side chains, coupling agents, and crosslinking agents may contain Si-Si bonds, COC bonds, or other chemical bonds that cannot resist UV radiation. Therefore, after prolonged UV irradiation, cracks appear on the silicone sealant surface. Currently, solutions to this problem generally include increasing UV absorbers and light stabilizers to improve photothermal stability; eliminating the influence of photosensitizers to quench free radical ions and reduce the possibility of damage to the silicone sealant matrix; increasing the amount of phenyl polysiloxane in the silicone sealant to ensure that the material's side chains are not affected by UV radiation; and combining it with titanium dioxide to enhance the material's UV resistance.

[0015] When cracks appear on the surface of a material, it easily absorbs water, which can seep into the material's interior, leading to a decrease in strength due to hydrolysis. Conventional silicone structural adhesives have good hydrophobicity in their surface skin, but once cracks appear, water can easily enter the sealant along the cracks. After prolonged immersion in hot water under strong ultraviolet radiation (e.g., 1008 hours), the silicone resin will be destroyed by hydrolysis. To solve this problem, in addition to improving UV resistance to reduce surface damage, it is also necessary to improve the hydrophobicity and hydrolysis resistance of the silicone material itself.

[0016] To address the aforementioned technical problems, this invention improves the adhesion of the silicone resin upon contact with water by adding a post-crosslinking silane coupling agent. This allows for secondary crosslinking between the post-crosslinking silane coupling agent and the substrate and the hydrolyzed silicone resin under prolonged water immersion. Furthermore, adding polyether-modified silicone oil enhances the hydrophobicity of the silicone material; and adding a multifunctional coupling agent improves the adhesion between the silicone material and the substrate.

[0017] Specifically, as a first aspect of the present invention, a post-crosslinking silane coupling agent suitable for silicone sealants is provided, the post-crosslinking silane coupling agent being bis(diisopropyl ketone oxime)dimethoxysilane having the following structure:

[0018] ; where iPr is isopropyl.

[0019] In embodiments of the present invention, a post-crosslinking silane coupling agent is applied to silicone sealant. Its steric hindrance effect, moderate activity, and water-triggered re-crosslinking ability ensure the adhesive effect of the silicone sealant after immersion in water. Specifically, the two large diisopropyl ketone oxime groups in the post-crosslinking silane coupling agent (also known as a "latent crosslinking silane coupling agent") provide sufficient steric hindrance for the central silicon atom, effectively preventing the catalyst in the silicone sealant from approaching and maintaining its inertness within the sealant. Compared to existing tetrafunctional molecules, the post-crosslinking silane coupling agent of the present invention has fewer active centers, making it more stable and ensuring its reliability and stability within the silicone sealant. In addition, the post-crosslinking silane coupling agent of the present invention forms a bissilol molecule ((CH3)2Si(OH)2) after hydrolysis. This bissilol molecule can act as a chain extender or crosslinking agent, and can re-link two polymer chains (Si-OH) formed by the hydrolysis of water molecules, effectively reconnecting the broken chains, repairing the network structure, restoring the mechanical properties of the silicone sealant, that is, achieving effective water-triggered re-crosslinking capability.

[0020] As a second aspect of the present invention, a method for preparing a post-crosslinking silane coupling agent is provided, comprising: reacting triethylamine with diisopropyl ketone oxime and dimethyl dichlorosilane to obtain bis(diisopropyl ketone oxime)dimethoxysilane.

[0021] Specifically, the raw materials used to prepare the above-mentioned post-crosslinked silane coupling agent include: triethylamine (Et3N), diisopropyl ketone oxime ((iPr)2C=N-OH), dimethyl dichlorosilane ((CH3)2SiCl2), and dry tetrahydrofuran (THF) (as solvent).

[0022] The equipment used to prepare the above-mentioned post-crosslinking silane coupling agent includes: a 50mL four-necked flask, a magnetic or mechanical stirrer, a constant pressure dropping funnel, a reflux condenser, a thermometer, a nitrogen system, an ice bath, and a rotary evaporator.

[0023] The specific preparation method includes: a synthesis step and a post-processing step.

[0024] The synthesis steps include the following steps 1-3.

[0025] Step 1: Add diisopropyl ketone oxime and triethylamine (molar ratio 2:2.2, with a slight excess of triethylamine to ensure neutralization of all HCl) to a four-necked flask, dissolve in dry tetrahydrofuran, and place the system in an ice-water bath (0-5°C) under nitrogen protection and stirring.

[0026] Step 2: Slowly add a tetrahydrofuran solution of dimethyldichlorosilane through a constant pressure dropping funnel, strictly controlling the dropping rate (e.g., 20 drops / min) and keeping the reaction temperature below 10°C.

[0027] Step 3: After the addition in Step 2 is complete, remove the ice bath and allow the reactants to naturally warm to room temperature. Continue stirring the reaction at room temperature for 12 hours.

[0028] Post-processing includes: after the reaction in step 3 is completed, filtration is performed to remove the white precipitate of triethylamine hydrochloride generated during the reaction. The filtrate is then distilled under reduced pressure at <40°C using a rotary evaporator to recover the tetrahydrofuran solvent. Subsequently, the crude product is collected by reduced pressure distillation to obtain the fraction with a specific boiling range, yielding the high-purity final product, i.e., the post-crosslinked silane coupling agent.

[0029] The reaction formula for preparing the post-crosslinked silane coupling agent according to the present invention is as follows:

[0030] ((CH3)2SiCl2+2(iPr)2C=N-OH+2Et3N→((CH3)2Si[ON=C(iPr)2]2+2Et3N·HCl↓

[0031] As a third aspect of the present invention, a water-resistant and UV-resistant silicone adhesive is provided, comprising: polysiloxane resin, polydimethylsiloxane, polyether-modified silicone oil, ethylenediaminetetraacetic acid chelating agent, color paste, reactive silicone oil, a first silane coupling agent, an organotin catalyst, and a post-crosslinking silane coupling agent.

[0032] In embodiments of the present invention, a synthesized post-crosslinking silane coupling agent is applied to a silicone sealant formulation. Its steric hindrance effect, appropriate activity, and water-triggered re-crosslinking ability ensure the adhesive performance of the silicone sealant after immersion in water or contact with water. Furthermore, a polyether-modified silicone oil is introduced into the silicone sealant formulation. This oil can migrate to the silicone sealant interface and form a durable hydrophobic protective layer. Combined with the aforementioned water-induced post-crosslinking scheme, the adhesive performance of the silicone sealant after immersion in water can be improved. By adding a chelating agent to eliminate the influence of photosensitizers (such as residual organic catalysts) in the silicone sealant, free radical ions are quenched, side reactions are avoided, and the degradation of the silicone sealant backbone by the organic catalyst is eliminated, reducing the possibility of damage to the silicone sealant matrix.

[0033] According to an embodiment of the present invention, the polyether-modified silicone oil is obtained by reacting α-isopropylene-ω-butyl polyoxypropylene ether with hydrogen-containing silicone oil in the presence of a caster catalyst and an alkynol inhibitor, wherein the molecular weight of the polysiloxane resin is 30,000 to 80,000.

[0034] In embodiments of the present invention, α-isopropenyl-ω-butyl polyoxypropylene ether is used as the reactant. The "isopropenyl" group provides a highly reactive terminal double bond; the "butyl" group, as the end-capping group, eliminates the highly hygroscopic hydroxyl groups at the polyether ends, transforming them into more inert and hydrophobic ether bonds, thus completely blocking the main pathway for water molecules to bind to the polyether chain via hydrogen bonds; the "polyoxypropylene ether" segment ensures strong hydrophobicity throughout the chain, allowing it to migrate to the silicone sealant interface to form a durable hydrophobic protective layer, extending its service life. Furthermore, the methyl groups attached to its sides provide strong spatial shielding while also offering some hydrophobic properties. In addition, the polyether segment itself has strong hydrolysis resistance, ensuring it is not hydrolyzed or is difficult to hydrolyze in a water-immersion environment, thus providing a second layer of protection against hydrolysis while maintaining hydrophobicity.

[0035] The raw materials used to prepare the above-mentioned polyether-modified silicone oil include:

[0036] Hydrogen-containing silicone oil has a hydrogen content of 0.5-1.2 wt%, and the hydrogen content determines the modified density.

[0037] α-Isopropylene-ω-butyl polyoxypropylene ether has a molecular weight of 500-1000 g / mol. If the molecular weight is too small, it will affect the migration of hydrophobic segments. If it is too large, it may lead to poor compatibility with other components in silicone sealant.

[0038] The cassiterite catalyst is an isopropanol solution of chloroplatinic acid, wherein the platinum content is approximately 0.1-0.5 wt%.

[0039] Alkynol inhibitors are alkynol compounds, such as 1-ethynyl-1-cyclohexanol, used to control reaction rates and prevent explosive polymerization.

[0040] Solvent: Toluene or isopropanol, used for dilution and to ensure homogeneity of the reaction.

[0041] Nitrogen: High-purity nitrogen, used for protection and deoxygenation of the reaction system.

[0042] The equipment used to prepare the above-mentioned polyether-modified silicone oil includes: a 250mL four-necked flask, a mechanical stirrer, a thermometer, a condenser, a constant-pressure dropping funnel, an oil bath, a nitrogen system (with a bubbler), and a rotary evaporator. Before use, the reaction apparatus is first set up by placing the four-necked flask in an oil bath and attaching the mechanical stirrer, condenser, thermometer, and constant-pressure dropping funnel. The upper end of the condenser is connected to the nitrogen system and the exhaust gas outlet.

[0043] Raw material pretreatment: Dissolve the hydrogen-containing silicone oil and α-isopropylene-ω-butyl polyoxypropylene ether in an appropriate amount of toluene, wherein the solid content is controlled at 50%-70%. Dilute the caster catalyst 10 times with isopropanol for later use.

[0044] The specific method for preparing polyether-modified silicone oil includes the following steps 1-5.

[0045] Step 1 (Initial Feeding): Add the dissolved mixture of hydrogen-containing silicone oil and α-isopropenyl-ω-butyl polyoxypropylene ether to a four-necked flask.

[0046] Step 2 (System Protection): Turn on nitrogen and purge the reaction flask at a medium flow rate (about 50-100 mL / min) for 15-20 min to ensure that the air is completely replaced.

[0047] Step 3 (Heating and Adding Inhibitor): Start stirring and oil bath heating, slowly raising the temperature to 60°C. Then add the calculated amount of alkynol inhibitor (approximately 1-5% of the mass of the platinum catalyst) through a syringe.

[0048] Step 4 (Catalytic reaction): Using a constant pressure dropping funnel, slowly add the diluted Castells catalyst solution, controlling the dropping rate and maintaining the reaction temperature at 85±5℃. This process may be slightly exothermic and requires close monitoring.

[0049] Step 5 (Insulation Reaction): After the caster catalyst solution from Step 4 has been added dropwise, continue the reaction at this temperature for 4-6 hours. During this period, monitor the Si-H characteristic peak (2160 cm⁻¹) using thin-layer chromatography (TLC) or Fourier transform infrared spectroscopy (FT-IR). -1 The disappearance of ) is used to determine whether the reaction is complete.

[0050] The specific method for preparing polyether-modified silicone oil also includes post-treatment and purification, specifically including the following steps 6-9.

[0051] Step 6 (Cooling): After the reaction in Step 5 is completed, cool the reaction solution to room temperature (below 25°C).

[0052] Step 7 (Catalyst removal, optional, but crucial for stability): Add a small amount (e.g., 1-2 wt%) of adsorbent (e.g., activated carbon or neutral alumina) to the reaction solution, stir for 1-2 h, and then filter to remove residual cassette catalyst (i.e., platinum catalyst).

[0053] Step 8 (Solvent Removal): Transfer the filtrate to a rotary evaporator and distill under reduced pressure at a water bath temperature of 60-70℃ to recover the toluene solvent and obtain the crude product.

[0054] Step 9 (Further Purification): To further remove unreacted α-isopropenyl-ω-butyl polyoxypropylene ether and small molecule impurities, the crude product can be dissolved in n-hexane, washed multiple times with deionized water, and the organic phase separated. Then, it can be rotary evaporated again to obtain the purified product.

[0055] In embodiments of the present invention, to ensure complete reaction of the hydrogen-containing silicone oil (containing Si-H) and avoid adverse effects of residual Si-H in subsequent use of the silicone sealant, α-isopropylene-ω-butyl polyoxypropylene ether needs to be slightly in excess, i.e., the molar ratio of α-isopropylene-ω-butyl polyoxypropylene ether to the hydrogen-containing silicone oil is controlled at 1:1.05~1.1. In step 4, the reaction temperature of hydrosilylation is controlled at 85±5℃, preferably 85℃. This temperature is the efficient reaction temperature for hydrosilylation. If the reaction temperature is too low, the reaction will be too slow; if the reaction temperature is too high, the risk of side reactions (such as silanol condensation) will increase. The alkynol inhibitor of the present invention can form reversible coordination with the platinum catalyst, inhibiting its activity at low temperatures, thereby preventing "explosive polymerization" and gelation caused by local overheating, and making the reaction stable and controllable.

[0056] According to an embodiment of the present invention, the average molecular weight of the polysiloxane resin (107 base glue) is 8000~35000.

[0057] According to an embodiment of the present invention, the reactive silicone oil in the two-component water-resistant and UV-resistant silicone sealant includes waterproofing agent 3# (methyltriethoxysilane hydrolyzed oligomer) and CG-103 (methyltrimethoxysilane).

[0058] According to embodiments of the present invention, the first silane coupling agent includes KH310 (methylphenylsiloxane), KH560 (γ-glycidoxypropyltrimethoxysilane), KH792 (N-β-aminoethyl-γ-aminopropyltrimethoxysilane), and dimethyldimethoxysilane.

[0059] According to an embodiment of the present invention, the organotin catalyst is selected from SD-L-101 (T9) and DMTDC (dimethyltin dinedecanoate).

[0060] According to embodiments of the present invention, the water-resistant and UV-resistant silicone sealant of the present invention further includes: a multifunctional crosslinking agent, functional additives, inorganic fillers, ultraviolet absorbers, and light stabilizers.

[0061] According to embodiments of the present invention, the multifunctional crosslinking agent contains two or more groups, or, after hydrolysis, two or more groups that can react with polysiloxane resins. Examples include silanes containing three methoxy and ethoxy groups, silanes containing two methoxy and ethoxy groups, and one or two epoxy and amino groups. For example, it can be selected from 3-aminopropyltriethoxysilane, trimethoxysilane, triethoxysilane, 1,2-bis(ethoxy)silyl ethane, and 1,2-bis(ethoxy)silyl ethane.

[0062] According to embodiments of the present invention, the functional additives include a dispersant (FC-16) and a leveling agent (FL-01).

[0063] According to embodiments of the present invention, the inorganic filler includes at least one of heavy calcium carbonate, hydrophobic nano-calcium (with stronger hydrophobicity than ordinary nano-calcium), nano-calcium, titanium dioxide, and hydrophobic hollow glass microspheres. The hydrophobic nano-calcium can be Tianshi M4 nano-calcium or Kemai 101 hydrophobic nano-calcium; ordinary nano-calcium has not undergone hydrophobic treatment, such as Shengtai 601 nano-calcium. The main component of the (hydrophobic) nano-calcium is calcium carbonate, among which Kemai 101 hydrophobic nano-calcium has higher hydrophobicity.

[0064] In embodiments of the present invention, ultraviolet absorbers and light stabilizers are added to absorb ultraviolet light and resist the damage to the material caused by ultraviolet rays and photothermal radiation; titanium dioxide is added to enhance the UV resistance of the silicone sealant. Adding inorganic fillers ensures the dimensional stability of the silicone sealant after immersion in water, preventing swelling. Functional additives are added to improve the rheological properties of the silicone sealant; inorganic fillers are added to improve the UV resistance and mechanical properties of the silicone sealant. Increasing the amount of methylphenylsiloxane (KH310) ensures that the side chains of the silicone sealant material are not affected by ultraviolet radiation. Adding polyether-modified silicone oil enhances the hydrophobicity of the material; combining it with hydrophobic nano-calcium or nano-calcium (i.e., nano-calcium carbonate) further enhances the hydrophobic properties. Adding multifunctional coupling agents improves the adhesion between the silicone sealant and the substrate; combining it with a post-crosslinking silane coupling agent allows for secondary crosslinking between the post-crosslinking silane coupling agent and the substrate and hydrolyzed resin under long-term water immersion, improving the adhesion performance of the material after contact with water.

[0065] According to embodiments of the present invention, the water-resistant and UV-resistant silicone sealant of the present invention can be a single component or a two-component sealant, and the components in the single component and the two-component sealant can be different.

[0066] Specifically, the two-component water-resistant and UV-resistant silicone sealant of the present invention includes component A and component B, and the mass ratio of component A to component B is 10-15:1.

[0067] Component A, by weight, includes: 25-50 parts polysiloxane resin, 5-15 parts polydimethylsiloxane, 5-10 parts polyether-modified silicone oil, 0.5-3 parts ethylenediaminetetraacetic acid chelating agent, 0-1 part functional additives, 50-110 parts inorganic fillers, 0.1-2 parts ultraviolet absorber, and 0.1-2 parts light stabilizer; wherein the functional additives include 0-0.5 parts dispersant and 0-0.5 parts leveling agent; the inorganic fillers include: 5-20 parts heavy calcium carbonate, 22-40 parts hydrophobic nano-calcium carbonate, 22-40 parts nano-calcium carbonate, 1-5 parts titanium dioxide, and 0-5 parts hydrophobic hollow glass microspheres; this color paste is a two-component color paste, including silicone oil, pigment, dispersant, and leveling agent. The silicone oil is either PDMS-350 or PDMS-100, with PDMS-350 being the primary component; it may also be a mixture of the two, with PDMS-350 having a higher proportion. The pigment is carbon black, titanium dioxide, or other colored pigments. The color paste in this invention does not contain thixotropic agents, but a small amount of bentonite is added as a thixotropic agent to improve anti-settling properties. The two-component color paste does not have high moisture content requirements, generally below 0.1%.

[0068] Component B, by weight, includes: 45-60 parts of color paste, 25-35 parts of reactive silicone oil, 1-5 parts of multifunctional crosslinking agent, 8-15 parts of primary silane coupling agent, 0.1-0.5 parts of organotin catalyst, and 1-5 parts of post-crosslinking silane coupling agent.

[0069] The water-resistant and UV-resistant silicone sealant of the present invention can also be a single component, namely, the single-component water-resistant and UV-resistant silicone sealant comprising: 80-120 parts of polysiloxane resin, 5-25 parts of polydimethylsiloxane, 0-10 parts of polyether-modified silicone oil, 0.5-3 parts of ethylenediaminetetraacetic acid (EDTA) chelating agent, 0.1-3 parts of functional additives, 98-147 parts of inorganic filler, 0.1-3 parts of UV absorber, 0.1-3 parts of light stabilizer, 5-15 parts of color paste, 5-15 parts of reactive silicone oil, 0.1-7 parts of first silane coupling agent, 0.05-0.5 parts of organotin catalyst, and 1-5 parts of post-crosslinking silane coupling agent. The inorganic filler comprises: 25-50 parts of heavy calcium carbonate, 70-90 parts of hydrophobic nano-calcium carbonate, and 3-7 parts of titanium dioxide. The composition of single-component and two-component color pastes is basically the same. The difference is that the silicone oil is mainly PDMS-100 silicone oil, which has a lower viscosity and a water content of less than 0.03%.

[0070] According to an embodiment of the present invention, a method for preparing a two-component water-resistant and UV-resistant silicone sealant includes: preparing component A, preparing component B, and mixing component A and component B.

[0071] Preparation of Component A: Polysiloxane resin, polydimethylsiloxane, polyether-modified silicone oil, and ethylenediaminetetraacetic acid chelating agent are added to a dual planetary mixer. The mixture is heated to 60°C and stirred for at least 30 minutes. Then, functional additives (such as dispersants and leveling agents) are added and stirred for 5-10 minutes until the materials are uniformly mixed. Inorganic fillers, UV absorbers, and light stabilizers are then added to the dual planetary mixer and stirred until the materials are uniformly dispersed. The temperature inside the reactor is raised to 100-110°C, and a vacuum is drawn to -0.095 MPa. After vacuuming for 1-3 hours, the temperature is lowered to below 50°C. The moisture content is measured to be 500-2000 ppm, and then the mixture is cooled and packaged to obtain Component A.

[0072] Preparation of component B: Mix the color paste, reactive silicone oil, multifunctional crosslinking agent, first silane coupling agent, and post-crosslinking silane coupling agent for 10-30 minutes until homogeneous, then add organotin catalyst and continue stirring until homogeneous to obtain component B.

[0073] After mixing component A and component B evenly in a weight ratio of 10-15:1, the mixture can be applied.

[0074] According to an embodiment of the present invention, a method for preparing a one-component water- and UV-resistant silicone sealant includes: adding polysiloxane resin, polydimethylsiloxane, polyether-modified silicone oil, and ethylenediaminetetraacetic acid chelating agent into a dual planetary mixer, heating to 60°C, and continuing to stir for at least half an hour. Then, adding functional additives (such as dispersants and leveling agents), and stirring for 5-10 minutes until the materials are uniformly mixed. Then, adding inorganic fillers and color paste into the dual planetary mixer and stirring, heating to 100-120°C, and applying a vacuum. When the water content is less than 0.1 wt%, cooling to 30°C-55°C to obtain a dry mixture; adding reactive silicone oil (such as D30, D90), multifunctional crosslinking agent, first silane coupling agent, post-crosslinking silane coupling agent, etc., to the aforementioned mixture, stirring for 10-30 minutes, then adding a catalyst, continuing to stir for 10-30 minutes, and packaging to obtain a one-component silicone structural sealant.

[0075] The technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0076] The raw materials used in the examples and comparative examples are as follows, all of which are commercially available. 107#-2W-XF (Xingfa, abbreviated as 107 base adhesive): polysiloxane resin with a molecular weight of 20,000. PDMS-350-XF (Xingfa): polydimethylsiloxane with a degree of polymerization of 350. Functional additives include FC-16 (dispersant) and FL-01 (leveling agent). Inorganic fillers include: Kemai 101 hydrophobic nano-calcium, Shengtai 601 nano-calcium, Tianshi M4 nano-calcium, titanium dioxide, and rich 800-mesh heavy calcium carbonate. Reactive silicone oils include: waterproofing agent 3# (methyltriethoxysilane hydrolyzed oligomer), CG-103 (methyltrimethoxysilane); or D30 (methyltributanone oxime silane), D90 (vinyltributanone oxime silane). The first silane coupling agents include: dimethyldimethoxysiloxane, KH310, KH560, and KH792. The multifunctional coupling agent is B3 (3-aminopropyltriethoxysilane). Organotin catalysts include T9 or DMTDC. UV absorber 326 (2'-hydroxy-3'-tert-butyl-5'-methylphenyl-5-chlorobenzotriazole) and light stabilizer 770 (bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate).

[0077] Example 1

[0078] Example 1 provides a two-component water-resistant and UV-resistant silicone sealant. The specific formula is shown in Table 1. Component A and component B are mixed in a mass ratio of 13:1 to prepare the silicone sealant (i.e., sealant). After stirring evenly, the sealant can be applied.

[0079] Table 1

[0080]

[0081] Example 2

[0082] Example 2 provides a two-component water-resistant and UV-resistant silicone sealant. The specific formula is shown in Table 2. Component A and component B are mixed in a mass ratio of 10:1 to prepare the silicone sealant (i.e., sealant). After stirring evenly, the sealant can be applied.

[0083] Table 2

[0084]

[0085] Example 3

[0086] Example 3 provides a two-component water-resistant and UV-resistant silicone sealant. The specific formula is shown in Table 3. Component A and component B are mixed in a mass ratio of 15:1 to prepare the silicone sealant (i.e., sealant). After stirring evenly, the sealant can be applied.

[0087] Table 3

[0088]

[0089] Comparative Example 1

[0090] Comparative Example 1 provides a two-component water-resistant and UV-resistant silicone sealant. The specific formulation is shown in Table 4. Component A and Component B are mixed in a mass ratio of 14:1 to prepare the silicone sealant (i.e., sealant). After stirring evenly, the sealant can be applied.

[0091] Table 4

[0092]

[0093] The above two-component sealant was used to prepare I-shaped test blocks according to the requirements of standard GB 16776-2025. Glass was bonded to one side and aluminum plate to the other side. After curing, the basic mechanical properties were tested, and then water-UV aging was carried out. After aging, the mechanical properties were tested, and the bonding failure mode was marked. The specific test results are shown in Table 5.

[0094] Table 5

[0095]

[0096] Note: CF represents cohesive failure; AF represents bond failure.

[0097] As can be seen from Examples 1-3 above, all of the above examples can meet the requirements of water-UV testing. The level of their basic mechanical properties mainly depends on the ratio of component A to component B. The amount of 107-based adhesive determines the mechanical properties. The polyether-modified silicone oil and post-crosslinking silane coupling agent of the present invention are mainly used to improve water-UV resistance, but cannot improve the basic mechanical properties of the structural adhesive.

[0098] Example 4

[0099] The above method was used to prepare a single-component water-resistant and UV-resistant silicone sealant. The specific formula is shown in Table 6. After the components are mixed evenly, the silicone sealant (i.e., sealant) is prepared.

[0100] Table 6

[0101]

[0102] Example 5

[0103] The above method was used to prepare a single-component water-resistant and UV-resistant silicone sealant. The specific formula is shown in Table 7. After the components are mixed evenly, the silicone sealant (i.e., sealant) is prepared.

[0104] Table 7

[0105]

[0106] Example 6

[0107] The above method was used to prepare a single-component water-resistant and UV-resistant silicone sealant. The specific formula is shown in Table 8. After the components are mixed evenly, the silicone sealant (i.e., sealant) is prepared.

[0108] Table 8

[0109]

[0110] Comparative Example 2

[0111] The above method was used to prepare a single-component water-resistant and UV-resistant silicone sealant. The specific formula is shown in Table 9. After the components are mixed evenly, the silicone sealant (i.e., sealant) is prepared.

[0112] Table 9

[0113]

[0114] The above-mentioned single-component sealant was used to prepare I-shaped test blocks according to the requirements of standard GB 16776-2025. Glass was bonded to one side and aluminum plate to the other side. After curing, the basic mechanical properties were tested, and then water-UV aging was carried out. After aging, the mechanical properties were tested, and the bonding failure mode was marked. The specific test results are shown in Table 10.

[0115] Table 10

[0116]

[0117] Note: CF represents cohesive failure; AF represents bond failure.

[0118] In Example 6, the basic mechanical properties are relatively low, and hydrophobic silicone oil (i.e., polyether-modified silicone oil) is not necessarily required to improve hydrophobicity and hydrolysis resistance. With the action of a post-crosslinking silane coupling agent, the bonding strength after water-UV irradiation is guaranteed to be greater than the strength of the adhesive itself, and cohesive failure can still be achieved. The main difference between Examples 4-6 is that the amount of base adhesive determines the mechanical properties. The difference from Comparative Example 2 is that Comparative Example 2 did not use conventional water- and UV-resistant methods alone, and therefore cannot guarantee compliance after the water-UV test.

[0119] In summary, this invention, through the combination of multiple components including a post-crosslinking silane coupling agent, a chelating agent, titanium dioxide, a first silane coupling agent, an ultraviolet absorber, a light stabilizer, and functional additives, can significantly improve the UV resistance of silicone adhesive materials, prevent or reduce the risk of surface cracking, and thus reduce the risk of water erosion to the bonding surface. The composite of the aforementioned components enhances water resistance and hydrophobicity, ensuring effective adhesion after immersion in water. Adjusting the dosage of the multifunctional coupling agent, the first silane coupling agent, and increasing KH310 further improves the bonding effect; the reaction of the post-crosslinking silane coupling agent enhances the adhesion effect after contact with water.

[0120] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. 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. A post-crosslinking silane coupling agent suitable for silicone sealants, characterized in that, The post-crosslinking silane coupling agent is bis(diisopropyl ketone oxime)dimethoxysilane, which has the following structure: ； Where iPr is isopropyl.

2. The method for preparing the post-crosslinking silane coupling agent as described in claim 1, characterized in that, include: Triethylamine reacts with diisopropyl ketone oxime and dimethyldichlorosilane to give bis(diisopropyl ketone oxime)dimethoxysilane.

3. A water-resistant and UV-resistant silicone sealant, characterized in that, include: Polysiloxane resin, polydimethylsiloxane, polyether-modified silicone oil, ethylenediaminetetraacetic acid chelating agent, color paste, reactive silicone oil, first silane coupling agent, organotin catalyst, and post-crosslinking silane coupling agent as described in claim 1.

4. The water-resistant and UV-resistant silicone sealant according to claim 3, characterized in that, Also includes: Multifunctional crosslinking agents, functional additives, inorganic fillers, ultraviolet absorbers, and light stabilizers; The water-resistant and UV-resistant silicone sealant can be a single-component or a two-component sealant, and the components in the single-component and two-component sealants can be different.

5. The water-resistant and UV-resistant silicone sealant according to claim 4, characterized in that, The water-resistant and UV-resistant silicone sealant is a two-component water-resistant and UV-resistant silicone sealant comprising component A and component B, with a mass ratio of component A to component B of 10-15:

1. Component A includes: 25-50 parts of polysiloxane resin, 5-15 parts of polydimethylsiloxane, 5-10 parts of polyether-modified silicone oil, 0.5-3 parts of ethylenediaminetetraacetic acid chelating agent, 0-1 part of functional additives, 50-110 parts of inorganic filler, 0.1-2 parts of ultraviolet absorber, and 0.1-2 parts of light stabilizer; Component B includes: The mixture comprises 45-60 parts of color paste, 25-35 parts of reactive silicone oil, 1-5 parts of multifunctional crosslinking agent, 8-15 parts of first silane coupling agent, 0.1-0.5 parts of organotin catalyst, and 1-5 parts of post-crosslinking silane coupling agent as described in claim 1.

6. The water-resistant and UV-resistant silicone sealant according to claim 4, characterized in that, The functional additives include 0-0.5 parts dispersant and 0-0.5 parts leveling agent; The inorganic filler comprises: 5-20 parts heavy calcium carbonate, 22-40 parts hydrophobic nano-calcium carbonate, 22-40 parts nano-calcium carbonate, 1-5 parts titanium dioxide, and 0-5 parts hydrophobic hollow glass microspheres. The first silane coupling agent includes KH310, KH560, KH792, and dimethyldimethoxysiloxane.

7. The water-resistant and UV-resistant silicone sealant according to claim 3, characterized in that, The water-resistant and UV-resistant silicone sealant is a one-component water-resistant and UV-resistant silicone sealant, comprising: The composition includes 80-120 parts of polysiloxane resin, 5-25 parts of polydimethylsiloxane, 0-10 parts of polyether-modified silicone oil, 0.5-3 parts of ethylenediaminetetraacetic acid chelating agent, 0.1-3 parts of functional additives, 98-147 parts of inorganic filler, 0.1-3 parts of ultraviolet absorber, 0.1-3 parts of light stabilizer, 5-15 parts of color paste, 5-15 parts of reactive silicone oil, 0.1-7 parts of first silane coupling agent, 0.05-0.5 parts of organotin catalyst, and 1-5 parts of post-crosslinking silane coupling agent as described in claim 1.

8. The water-resistant and UV-resistant silicone sealant according to claim 7, characterized in that, The inorganic filler comprises: 25-50 parts heavy calcium carbonate, 70-90 parts hydrophobic nano-calcium carbonate, and 3-7 parts titanium dioxide; The silane coupling agents include KH310, KH560, and KH792.

9. The water-resistant and UV-resistant silicone sealant according to any one of claims 3-8, characterized in that, The polyether-modified silicone oil is obtained by reacting α-isopropenyl-ω-butyl polyoxypropylene ether with hydrogen-containing silicone oil in the presence of a cassiterite catalyst and an alkynol inhibitor. The molecular weight of the polysiloxane resin is 30,000 to 80,000.

10. The application of the water-resistant and UV-resistant silicone sealant as described in any one of claims 3-9 in building sealants.

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