Acid mist corrosion resistant two-component silicone structural adhesive and preparation method thereof

Abstract

The application discloses an acid mist corrosion resistant two-component silicone structural adhesive and a preparation method thereof. The acid mist corrosion resistant two-component silicone structural adhesive comprises an A component and a B component. The A component comprises raw materials in the following mass fractions: 107 base adhesive 90-110 parts, filler 85-135 parts, and dimethyl silicone oil 5-25 parts. The B component comprises raw materials in the following mass fractions: fumed silica 5-9 parts, carbon black 15-20 parts, dimethyl silicone oil 25-32 parts, cross-linking agent 15-38 parts, coupling agent 18-45 parts, and catalyst 0.01-0.1. The coupling agent comprises acrylic modified amino silane oligomer in a mass fraction of 10-25 parts. The acrylic modified amino silane oligomer can react and cross-link with the 107 base adhesive, and simultaneously introduces a hydrophobic alkyl group, so that the compactness and water resistance of the silicone structural adhesive are improved, the acid mist is not easy to enter the interior of the silicone structural adhesive, and the intervention of corrosion medium is reduced.

Description

Technical Field

[0001] This application relates to the field of silicone structural adhesives, and in particular to a two-component silicone structural adhesive resistant to acid mist corrosion and its preparation method. Background Technology

[0002] With the rapid development of industry, the sulfur oxides and nitrogen oxides emitted from the combustion of large amounts of fossil fuels combine with water vapor in the air to gradually form acid mist. The acid mist is highly corrosive and, after being released into the atmosphere, causes acid deposition in the atmospheric environment, which in turn corrodes the exterior surfaces of buildings and other structures, resulting in losses in daily life and production.

[0003] Structural adhesives used in building curtain walls to connect metal components to curtain wall glass have weak resistance to corrosive media in acid mist environments. Corrosive media cause the cured structural adhesive to crack, reducing its adhesion, and also corrode the metal components through the pores in the adhesive. Furthermore, existing technologies rarely document structural adhesives designed to resist acid mist corrosion. Summary of the Invention

[0004] To mitigate and reduce the corrosion of structural adhesives in acid mist environments, this application provides an acid mist-resistant two-component silicone structural adhesive and its preparation method.

[0005] In a first aspect, an acid mist resistant two-component structural adhesive comprises component A and component B, wherein component A and component B comprise the following raw materials in parts by weight:

[0006] Component A:

[0007] 90-110 parts of 107 base rubber;

[0008] 85-135 parts of filler;

[0009] 5-25 parts of dimethyl silicone oil;

[0010] Component B:

[0011] 5-9 parts of fumed silica;

[0012] 15-20 parts carbon black;

[0013] 25-32 parts of dimethyl silicone oil;

[0014] 15-38 parts of crosslinking agent;

[0015] 18–45 parts of coupling agent;

[0016] Catalyst 0.01–0.1 parts;

[0017] The coupling agent comprises 10 to 25 parts by weight of an acrylic acid-modified aminosilane oligomer.

[0018] Preferably, the mass ratio of component A to component B is (7-11):1.

[0019] Preferably, the degree of polymerization of the acrylic acid-modified aminosilane oligomer is 2 to 12.

[0020] Preferably, the viscosity of the 107-based adhesive is 50,000 to 80,000 cst.

[0021] Preferably, the crosslinking agent includes one or more of methyl orthosilicate, ethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, polyethyl orthosilicate, vinyltrimethoxysilane, and cyclopentyltriethoxysilane.

[0022] Preferably, the filler comprises one or a combination of several of nano-calcium carbonate, diatomaceous earth, kaolin, and silica powder.

[0023] More preferably, the filler is nano-calcium carbonate; preferably, the particle size of nano-calcium carbonate is 30-100 nm.

[0024] Preferably, the viscosity of the dimethyl silicone oil is 50–1000 mm. 2 / s.

[0025] By adopting the above technical solution, the silicone structural adhesive in this application is a two-component silicone structural adhesive. In the process of use, component A and component B need to be mixed in a certain mass ratio to achieve its sealing and bonding effect.

[0026] The silicone structural adhesive in this application is mainly a polymer compound composed of silicon-oxygen chains as the main chain. Compared with hydrocarbon chains as the main chain, the molecular chains of silicon-oxygen chains are mainly bonded by covalent bonds. However, the covalent bond strength is relatively weak. In acid mist environments, due to the presence of various acidic corrosive media, the molecular chains in the silicone structural adhesive are easily broken, resulting in chain lysis and loss of adhesive ability. Adding fumed silica to the silicone structural adhesive allows the silanol groups on its surface to combine with the 107-based adhesive to form a three-dimensional network structure, achieving a reinforcing effect, increasing the density of the silicone structural adhesive, and improving its corrosion resistance. However, the silanol groups on the surface of fumed silica are highly reactive and hydrophilic, capable of adsorbing water molecules. If this adsorbed water is not removed in time, it will affect the performance of the silicone structural adhesive. Therefore, acrylic acid-modified aminosilane oligomers are also added to the silicone structural adhesive.

[0027] The addition of acrylic-modified aminosilane oligomers introduces hydrophobic alkyl groups into the system. The addition of hydrophobic groups can effectively improve the waterproof and impermeable properties of silicone structural adhesives, making it difficult for acid mist and water molecules in the air to penetrate into the silicone structural adhesive, thereby reducing the intervention of corrosive media. At the same time, when components A and B are mixed, the acrylic-modified aminosilane oligomers in component B can react with the 107-based adhesive in component A to form Si-O-Si bonds, thereby forming a three-dimensional network structure in which molecular chains interweave, increasing the crosslinking density of the structural adhesive, making the resulting silicone structural adhesive structure more compact, and making it less likely for corrosive media such as acid mist to penetrate into the structural adhesive and cause structural adhesive cracking.

[0028] Preferably, the raw materials for the acrylic acid-modified aminosilane oligomer include an aminosilane coupling agent and an acrylic acid compound in a mass ratio of (12-18):1.

[0029] Preferably, the aminosilane coupling agent comprises one or a combination of several of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane, and 3-diethylenetriaminopropylmethyldimethoxysilane.

[0030] Preferably, the acrylic compound comprises methacrylic acid and propylacrylic acid in a mass ratio of (1.5 to 2.5):1.

[0031] More preferably, the mass ratio of methacrylic acid to propylacrylic acid is 2:1.

[0032] Preferably, the acrylic acid-modified aminosilane oligomer is prepared by the following method: adding an aminosilane coupling agent to a solvent and mixing evenly to obtain a mixed solution; adding a catalyst to the mixed solution; heating to 40-60°C and then adding deionized water; heating to 90-110°C with stirring; reacting for 3-5 hours to obtain a pre-reactant; adjusting the temperature of the pre-reactant to 40-60°C and adding an acrylic acid compound; reacting for 3-6 hours; and then obtaining the acrylic acid-modified aminosilane oligomer by vacuum distillation.

[0033] Preferably, the solvent includes one or more of methanol and ethanol; the catalyst includes dimethyl sulfoxide.

[0034] Preferably, the mass ratio of solvent to acrylic compound is (1.5–3.5):1; and the amount of catalyst added is 25–35% of the solvent mass.

[0035] Preferably, the amount of deionized water added is 50-60% of the solvent mass.

[0036] By employing the above technical solution, the aminosilane coupling agent, after being mixed in a solvent, undergoes alcoholysis under the action of a catalyst, generating highly reactive silanol groups. The acrylic compound contains chemically active carboxyl groups, which can undergo esterification with the silanol groups. Therefore, the acrylic compound can chemically bond and tightly connect with the aminosilane coupling agent to form acrylic-modified aminosilane oligomers. Through the crosslinking reaction between the acrylic-modified aminosilane oligomers and 107-based adhesive, hydrophobic groups can be introduced into the silicone structural adhesive, thereby improving its waterproof and impermeable properties, and further enhancing its resistance to acid mist corrosion. Simultaneously, the increased amino group density on the molecular chains of the oligomers formed by the self-polymerization of the aminosilane coupling agent strengthens the bond strength between the silicone structural adhesive and the substrate, effectively resisting the penetration of corrosive media such as acid mist.

[0037] The selected acrylic compounds are mostly short-chain acrylics, and preferably, combinations of acrylic compounds with different chain lengths. The hydrophobic alkyl groups contained therein improve the hydrophobicity of the silicone structural adhesive, while also exhibiting higher stability compared to long-chain acrylic compounds, and are less prone to molecular chain entanglement and low grafting rate with aminosilane coupling agents. The combination of different chain lengths can simultaneously compensate for the rigidity and toughness of the structure, which is beneficial to increasing the stability of the structure.

[0038] Preferably, the B component raw material further includes 2 to 5 parts by weight of graphene oxide; the oxygen content of the graphene oxide is 30 to 40%.

[0039] By adopting the above technical solution, graphene oxide has a small surface area and its sheet-like structure has good barrier properties. It can form curved paths in silicone structural adhesives, delaying the entry of corrosive media into the silicone adhesive and improving the silicone structural adhesive's impermeability. Compared with ordinary graphene, graphene oxide contains a large number of oxygen-containing groups on its surface, which have chemical affinity and are not prone to agglomeration, thus better leveraging the excellent properties of graphene itself.

[0040] Meanwhile, the surface of graphene oxide has a large number of oxygen-containing groups, among which the hydroxyl groups can undergo a dehydration reaction with the silanol groups contained in the silicone structural adhesive. This allows graphene oxide to connect with the molecular chains of the silicone structural adhesive, preventing it from easily detaching during subsequent use and thus preserving its corrosion resistance and reinforcing properties. Graphene oxide can also act as a linking compound between component A and component B, connecting the 107-based adhesive with the acrylic-modified aminosilane oligomer, increasing the crosslinking density of both, thereby increasing the density of the internal structure of the silicone structural adhesive and enhancing its resistance to the penetration of corrosive media such as acid mist.

[0041] Preferably, the coupling agent further includes one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, γ-glycidyletheroxypropyltrimethoxysilane, γ-glycidyletheroxypropyltriethoxysilane, γ-glycidyletheroxypropylmethyldiethoxysilane, γ-glycidyletheroxypropylmethyldiethoxysilane, 3-diethylenetriaminopropyltrimethoxysilane, and 3-cyclopentadienylpropyltriethoxysilane.

[0042] By adopting the above technical solution, the coupling agent also includes an aminosilane coupling agent, in which the amino groups can work together with the acrylic acid-modified aminosilane oligomer to bond the silicone structural adhesive to the active groups on the surface of the substrate such as metal components, thereby improving the bonding performance of the silicone structural adhesive.

[0043] Preferably, the catalyst comprises one or more of dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, and stannous octoate.

[0044] By adopting the above technical solution, the catalyst can improve the curing speed of the two-component silicone structural adhesive after the components A and B are mixed, thereby increasing work efficiency.

[0045] Secondly, this application provides a method for preparing an acid mist resistant two-component silicone structural adhesive, comprising the following steps:

[0046] Preparation of component A: After adding 107 base glue, filler and dimethyl silicone oil to the reaction vessel, stir for 1 to 3 hours under vacuum at 120 to 160°C to obtain component A;

[0047] Preparation of component B: Carbon black and dimethyl silicone oil are mixed evenly and added to a reaction vessel. The mixture is stirred under vacuum at 140-160°C for 10-20 minutes. Crosslinking agent, fumed silica and graphene oxide are added sequentially and stirred under vacuum for 20-40 minutes. Finally, coupling agent and catalyst are added and stirred under vacuum for 50-70 minutes to obtain component B.

[0048] Preferably, the vacuum conditions during the preparation of component A and component B are required to be within the range of -0.09 MPa to -0.1 MPa.

[0049] Preferably, graphene oxide is added during the preparation of component B to enhance the acid mist corrosion resistance of the two-component silicone structural adhesive. At the same time, if graphene oxide is not added during the preparation process, the silicone structural adhesive can still meet the requirements for acid mist corrosion resistance.

[0050] In summary, this application has the following beneficial effects:

[0051] 1. During the curing process, the silanol groups on the surface of the fumed silica in component B can combine with the 107-based adhesive in component A to form a three-dimensional network structure, which not only provides reinforcement but also increases the density of the two-component silicone structural adhesive and improves its corrosion resistance.

[0052] 2. The addition of acrylic-modified aminosilane oligomers in component B introduces hydrophobic alkyl groups into the system, which significantly improves the waterproof and impermeable properties of the silicone structural adhesive. This prevents acid mist and water molecules from penetrating the silicone structural adhesive, thereby reducing the intrusion of corrosive media. Simultaneously, after mixing components A and B, the acrylic-modified aminosilane oligomers in component B react with the 107-based adhesive in component A to form Si-O-Si bonds, resulting in a three-dimensional network structure with interwoven molecular chains. This increases the crosslinking density of the structural adhesive, making the resulting silicone structural adhesive structure more compact and less susceptible to the penetration of corrosive media such as acid mist, thus preventing structural adhesive degradation.

[0053] 3. Component B also contains graphene oxide, which acts as a bridge between the acrylic-modified aminosilane oligomer and the 107-based adhesive in component A, increasing the crosslinking density and resulting in a denser silicone structural adhesive structure. Simultaneously, the oxygen-containing groups on the graphene oxide surface undergo a dehydration reaction with the silanol groups in the silicone structural adhesive, increasing the bonding strength and preventing detachment. The sheet-like structure of graphene oxide itself creates a curved path in the two-component silicone structural adhesive, delaying the entry of corrosive media and increasing the adhesive's impermeability. Detailed Implementation

[0054] Preparation example of acrylic acid modified aminosilane oligomers

[0055] Preparation Example 1: An acrylic acid-modified aminosilane oligomer was prepared according to the following method:

[0056] Take 960g of aminosilane coupling agent, which contains 450g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 270g of N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane and 240g of 3-diethylenetriaminopropylmethyldimethoxysilane. Mix them evenly and add 150g of methanol. Continue stirring and mixing. Add 45g of dimethyl sulfoxide. Raise the temperature to 50℃ and add 82g of deionized water. Raise the temperature to 100℃ and stir the reaction for 4h at a constant temperature to obtain a pre-reaction solution.

[0057] The temperature of the pre-reaction solution was adjusted to 40℃. 60g of acrylic acid compound, which contains 40g of methacrylic acid and 20g of propylacrylic acid, was mixed evenly and added to the pre-reaction solution. After stirring and reacting for 5 hours, the acrylic acid-modified aminosilane oligomer was obtained by vacuum distillation.

[0058] Preparation Examples 2 to 5 describe an acrylic acid-modified aminosilane oligomer, which differs from Preparation Example 1 only in the ratio of the raw materials used, as shown in Table 1.

[0059] Table 1. Formulations of Preparation Examples 1 to 5

[0060]

[0061]

[0062] Preparation Example 6: An acrylic acid-modified aminosilane oligomer, differing from Preparation Example 1 only in that the amount of aminosilane coupling agent added is 1140g, which includes 520g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 340g of N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane and 280g of 3-diethylenetriaminopropylmethyldimethoxysilane.

[0063] Preparation Example 7: An acrylic acid-modified aminosilane oligomer, which differs from Preparation Example 1 only in that the amount of aminosilane coupling agent added is 660g, which includes 340g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 180g of N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane and 140g of 3-diethylenetriaminopropylmethyldimethoxysilane.

[0064] Preparation Example 8, an acrylic acid-modified aminosilane oligomer, differs from Preparation Example 1 only in that the acrylic acid compound includes 60g of methacrylic acid.

[0065] Preparation Example 9: An acrylic acid-modified aminosilane oligomer, which differs from Preparation Example 1 only in that the acrylic acid compound includes 60g of propylacrylic acid.

[0066] Preparation Example 10 is an acrylic acid-modified aminosilane oligomer, which differs from Preparation Example 1 only in that no acrylic acid compound is added.

[0067] Example

[0068] Example 1: A two-component silicone structural adhesive resistant to acid mist corrosion was prepared according to the following method: Preparation of component A: 1 kg of 107 base adhesive (average viscosity 50000 cst), 1.1 kg of nano-calcium carbonate (particle size 50-80 nm), and 0.15 kg of dimethyl silicone oil (average viscosity 500 mm) were taken. 2 Add ( / s) to the reactor, adjust the reactor temperature to 140℃ and the vacuum degree to -0.1Mpa, and stir for 2h to obtain component A.

[0069] Preparation of Component B: Take 0.18 kg of carbon black (type N220) and 0.28 kg of dimethyl silicone oil (average viscosity 500 mm). 2 After mixing evenly, add the mixture to the reactor. Adjust the reactor temperature to 150℃ and the vacuum degree to -0.1Mpa. Stir and mix for 10 min, then add 0.26 kg of methyl orthosilicate. Stir and mix for 30 min under the same conditions. After stirring, add 0.07 kg of fumed silica (model LM-150) and 0.035 kg of graphene oxide (model G139803). Continue stirring and mixing for 30 min under the same conditions. Finally, add 0.18 kg of acrylic acid modified aminosilane oligomer obtained in Preparation Example 1, 0.14 kg of γ-aminopropyltrimethoxysilane, and 0.0005 g of dibutyltin dilaurate. Stir and mix for 60 min under the same conditions to obtain component B.

[0070] When using, mix component A and component B at a mass ratio of 8:1.

[0071] Example 2 is a two-component silicone structural adhesive resistant to acid mist corrosion. The only difference from Example 1 is that graphene oxide is not added during the preparation of component B.

[0072] Examples 3 to 12 describe a two-component silicone structural adhesive resistant to acid mist corrosion. The only difference between this adhesive and Example 2 is the ratio of the raw materials used, as shown in Table 2.

[0073] Table 2 Formulation Tables for Examples 2 to 12

[0074]

[0075]

[0076] Examples 3 and 4 use the acrylic acid-modified aminosilane oligomers prepared in Preparation 2, Example 7 uses the acrylic acid-modified aminosilane oligomers prepared in Preparation 3, Example 8 uses the acrylic acid-modified aminosilane oligomers prepared in Preparation 4, and Examples 9 and 10 use the acrylic acid-modified aminosilane oligomers prepared in Preparation 5.

[0077] Example 13, an acid mist resistant two-component silicone structural adhesive, differs from Example 1 only in that the amount of graphene oxide added in the preparation of component B is 0.02 kg.

[0078] Example 14, a two-component silicone structural adhesive resistant to acid mist corrosion, differs from Example 1 only in that the amount of graphene oxide added during the preparation of component B is 0.05 kg.

[0079] Example 15: A two-component silicone structural adhesive resistant to acid mist corrosion, differing from Example 1 only in that the amount of graphene oxide added during the preparation of component B is 0.07 kg.

[0080] Example 16, an acid mist resistant two-component silicone structural adhesive, differs from Example 2 only in that, in the preparation of component B, an equal amount of acrylic acid modified aminosilane oligomer prepared in Preparation Example 6 is used to replace the acrylic acid modified aminosilane oligomer prepared in Preparation Example 1.

[0081] Example 17, an acid mist resistant two-component silicone structural adhesive, differs from Example 2 only in that, in the preparation of component B, an equal amount of acrylic acid modified aminosilane oligomer prepared in Preparation Example 7 is used to replace the acrylic acid modified aminosilane oligomer prepared in Preparation Example 1.

[0082] Example 18, a two-component silicone structural adhesive resistant to acid mist corrosion, differs from Example 2 only in that, in the preparation of component B, an equal amount of acrylic acid-modified aminosilane oligomer prepared in Preparation Example 8 is used to replace the acrylic acid-modified aminosilane oligomer prepared in Preparation Example 1.

[0083] Example 19, a two-component silicone structural adhesive resistant to acid mist corrosion, differs from Example 2 only in that, in the preparation of component B, an equal amount of acrylic acid modified aminosilane oligomer prepared in Preparation Example 9 is used to replace the acrylic acid modified aminosilane oligomer prepared in Preparation Example 1.

[0084] Comparative Example

[0085] Comparative Example 1, an acid mist resistant two-component silicone structural adhesive, differs from Example 2 only in that, during the preparation of component B, the amount of acrylic acid modified aminosilane oligomer added in Example 1 is 0.08 kg.

[0086] Comparative Example 2, an acid mist resistant two-component silicone structural adhesive, differs from Example 2 only in that, in the preparation process of component B, the amount of acrylic acid modified aminosilane oligomer obtained in Example 1 added is 0.27 kg.

[0087] Comparative Example 3, an acid mist corrosion resistant two-component silicone structural adhesive, differs from Example 2 only in that, in the preparation of component B, an equal amount of acrylic acid modified aminosilane oligomer prepared in Preparation Example 10 is used to replace the acrylic acid modified aminosilane oligomer prepared in Preparation Example 1.

[0088] Comparative Example 4, an acid mist corrosion resistant two-component silicone structural adhesive, differs from Example 2 only in that, in the preparation of component B, an equal amount of γ-aminopropyltrimethoxysilane is used to replace the acrylic acid modified aminosilane oligomer obtained in Preparation Example 1.

[0089] Performance testing

[0090] 1. Basic Performance Testing of Structural Adhesives: The tensile bond strength at 23°C, tensile bond strength at 80°C, shear strength at 23°C, and tear resistance of the two-component silicone structural adhesives prepared in Examples 1-19 and Comparative Examples 1-4 were tested according to GB / T 37126-2018 "Test Methods for Building Sealants for Structural Assembly". The tensile bond strength at 80°C and tear resistance of the structural adhesives were characterized by the retention rate of the tensile bond strength. The test results are shown in Table 3.

[0091] 2. Structural adhesive acid mist corrosion resistance test: According to GB / T 37126-2018 "Test Methods for Building Sealants for Structural Assembly", the two-component silicone structural adhesives prepared in Examples 1-19 and Comparative Examples 1-4 were tested according to GB / T 9789-2008 "Sulfur Dioxide Corrosion Test on Metals and Other Inorganic Coatings under Normal Condensation Conditions".

[0092] The samples prepared according to the standard were treated in a sulfur dioxide test chamber for 8 hours and then placed under standard experimental conditions for 16 hours. This process constituted one cycle, and a total of 20 cycles were performed before tensile bond strength testing. The acid mist corrosion resistance was characterized by the retention rate of tensile bond strength. The test results are shown in Table 3.

[0093] Table 3. Basic performance and acid mist corrosion resistance test results

[0094]

[0095]

[0096] According to Table 3, and in conjunction with Examples 2, 1, and 2, it can be seen that the tensile adhesion and shear strength of Comparative Examples 1 and 2 at 23°C are significantly lower than those of Example 2. The tensile adhesion at 80°C, i.e., the retention rate of tensile adhesion strength at 80°C, is also significantly lower than that of Example 2. Tear resistance and acid mist corrosion resistance are also lower than those of Example 2. This indicates that the basic properties, stability, and acid mist corrosion resistance of Comparative Examples 1 and 2 are all significantly lower than those of Example 2. The reason for this may be that the amount of acrylic acid-modified aminosilane oligomers added in Comparative Examples 1 and 2 is different; the amount added in Comparative Example 1 is less than the required range, while the amount added in Comparative Example 2 is more than the required range. When the amount of acrylic acid-modified aminosilane oligomer added decreases, the content of hydrophobic alkyl groups in the prepared two-component silicone structural adhesive decreases, resulting in a decline in the waterproof and impermeable properties of the silicone structural adhesive. Simultaneously, the reduced addition amount leads to decreased adhesion to 107-based adhesives, fumed silica, etc., a decrease in crosslinking density, and a decrease in the density of the silicone structural adhesive, resulting in a decline in overall stability and acid mist corrosion resistance. When the amount of acrylic acid-modified aminosilane oligomer added increases, the silicone structural adhesive contains a large number of hydrophobic groups. Since the silicone structural adhesive of this application is a two-component silicone structural adhesive, it requires the mixing of components A and B for further curing. When the proportion of hydrophobic groups in component B is large, the affinity with component A decreases, and the crosslinking density between various active groups in component B and component A decreases, leading to a significant decline in overall performance, stability, and acid mist corrosion resistance.

[0097] Combining Example 2 and Comparative Example 3, it can be seen that the tensile bond strength and shear strength of Comparative Example 3 at 23°C are significantly lower than those of Example 2. The tensile bond strength retention rate at 80°C is also significantly lower than that of Example 2. Tear resistance and acid mist corrosion resistance are also lower than those of Example 2. This indicates that the basic properties and stability of Comparative Example 3 are lower than those of Example 2, and its acid mist corrosion resistance is significantly lower. The reason for this may be that the aminosilane oligomer in Comparative Example 3 is not modified with acrylic acid, resulting in a silicone structural adhesive without hydrophobic functional groups. This significantly reduces its waterproof and impermeable properties, making it highly susceptible to interaction with moisture in the air and acid mist containing dissolved sulfur oxides and nitrogen oxides. Corrosive media can easily enter the structural adhesive, causing the silicon-oxygen bonds to break, thus greatly reducing its acid mist corrosion resistance.

[0098] Combining Example 2 and Comparative Example 4, it can be seen that the tensile adhesion and shear strength of Comparative Example 4 at 23°C are significantly lower than those of Example 2. The tensile adhesion at 80°C, i.e., the retention rate of tensile adhesion strength at 80°C, is also significantly lower than that of Example 2. Tear resistance and acid mist corrosion resistance are also lower than those of Example 2. This indicates that the basic performance and stability of Comparative Example 4 are lower than those of Example 2, and the acid mist corrosion resistance is significantly lower. The reason for this may be that in Comparative Example 4, a general aminosilane coupling agent was used instead of the acrylic acid-modified aminosilane oligomer. On the one hand, the hydrophobic effect of acrylic acid was lost, greatly reducing the waterproof and impermeable properties of the structural adhesive. On the other hand, the amino groups in the aminosilane coupling agent do not have the tightly packed amino groups found on the aminosilane oligomer molecular chain, resulting in a decreased ability to crosslink with other components and an overall decline in performance.

[0099] Combining Examples 1 and 2, it can be seen that the tensile bond strength and shear strength of Example 1 at 23°C are increased compared to Example 2. The tensile bond strength retention rate at 80°C is also increased compared to Example 2. Furthermore, the tear resistance and acid mist corrosion resistance are also increased compared to Example 2. This indicates that the basic performance, stability, and acid mist corrosion resistance of Example 1 are all improved compared to Example 2. This may be because graphene oxide was added in Example 1. Due to the sheet-like structure of graphene oxide, it can form a pathway in the silicone structural adhesive that delays the entry of corrosive media, thus improving the acid mist corrosion resistance of the prepared silicone structural adhesive. Simultaneously, the various oxygen-containing groups on the surface of graphene oxide can connect the active ingredients of components A and B, accelerating the curing speed, increasing structural density, and improving the performance of the structural adhesive.

[0100] Combining Examples 1, 13, and 14, it can be seen that the tensile adhesion and shear strength at 23°C, tensile adhesion at 80°C, tear resistance, and acid mist corrosion resistance of Examples 13 and 14 are not significantly different from those of Example 1. This indicates that the basic properties, stability, and acid mist corrosion resistance of Examples 13 and 14 are not significantly different from those of Example 1. This may be because the only difference between Examples 13 and 14 and Example 1 is the variation in the amount of graphene oxide added within the required range. This suggests that adjusting the amount of graphene oxide added within the required range has no significant impact on the various properties of the silicone structural adhesive.

[0101] Combining Examples 1 and 15, it can be seen that the tensile adhesion and shear strength at 23°C, the tensile adhesion at 80°C, and the tear resistance of Example 15 are lower than those of Example 1, indicating that the basic performance and stability of Example 15 are lower than those of Example 1. This may be because the amount of graphene oxide added in Example 15 exceeds the required range. Graphene oxide has good mechanical properties; when added in excessive amounts, the rigidity of the silicone structural adhesive increases while its toughness decreases, leading to a decline in the basic performance and stability of the silicone structural adhesive.

[0102] Combining Examples 2 and 3-12, it can be seen that the tensile adhesion and shear strength at 23°C, tensile adhesion at 80°C, tear resistance, and acid mist corrosion resistance of Examples 3-12 are not significantly different from those of Example 2. This indicates that the basic properties, stability, and acid mist corrosion resistance of Examples 3-12 are not significantly different from those of Example 2. This may be because only the raw material ratios were adjusted in Examples 3-12, demonstrating that changing the raw material ratios within the required range has no significant impact on the performance of the silicone structural adhesive.

[0103] Based on Examples 2, 16, and 17, it can be seen that the tensile adhesion and shear strength of Examples 16 and 17 at 23°C are lower than those of Example 2. The tensile adhesion at 80°C (i.e., the retention rate of tensile adhesion strength at 80°C) is also lower than that of Example 2. Tear resistance and acid mist corrosion resistance are also lower than those of Example 2. This indicates that the basic properties, stability, and acid mist corrosion resistance of Examples 16 and 17 are all lower than those of Example 2. The reason for this may be that the amount of acrylic acid compound added during the preparation process of the acrylic acid-modified aminosilane oligomer used in Examples 16 and 17 differs from that in Example 2. In Example 16, the amount of acrylic acid compound added is less than the required range, while in Example 17, the amount of acrylic acid compound added is more than the required range. When the amount of acrylic compound added decreases, the number of alkyl groups in the prepared acrylic-modified aminosilane oligomer decreases, resulting in a reduction in the content of hydrophobic alkyl groups in the prepared two-component silicone structural adhesive. This leads to a decrease in the waterproof and impermeable properties of the silicone structural adhesive, as well as a decrease in its resistance to acid mist corrosion. When the amount of acrylic compound added increases, the overall affinity decreases during the acrylic-modified aminosilane oligomerization process. The binding between the aminosilane oligomer and the acrylic compound reaches saturation, and the molecular weight increases compared to the acrylic-modified aminosilane oligomer in Example 2. This results in a decrease in stability in the silicone structural adhesive, leading to a reduction in overall performance and resistance to acid mist corrosion.

[0104] Combining Examples 2, 18, and 19, it can be seen that the tensile adhesion, shear strength, tear resistance, and acid mist corrosion resistance of Examples 18 and 19 at 23°C are lower than those of Example 1. The tensile adhesion at 80°C is significantly lower than that of Example 2, indicating that the stability and acid mist corrosion resistance of Examples 18 and 19 are significantly lower than those of Example 2. This may be because the acrylic compound used in Example 18 is methacrylic acid, and the acrylic compound used in Example 19 is propylacrylic acid, while Example 2 uses an acrylic compound prepared by mixing the two. Compared to Example 2, in Example 18, the methacrylic acid chain segments are shorter, increasing the rigidity of the acrylic acid-modified aminosilane oligomer. However, when the material rigidity is too high, it is prone to brittleness and decreased stability. In Example 19, the propylacrylic acid chain segments are longer, without rigidity compensation, resulting in decreased strength and stability.

[0105] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A two-component silicone structural adhesive resistant to acid mist corrosion, characterized in that, It includes component A and component B, wherein component A and component B comprise the following raw materials in parts by mass: Component A: 90-110 parts of 107 base rubber; 85-135 parts of filler; 5-25 parts of dimethyl silicone oil; Component B: 5-9 parts of fumed silica; 15-20 parts carbon black; 25-32 parts of dimethyl silicone oil; Crosslinking agent 15-38 parts; 18–45 parts of coupling agent; Catalyst 0.01–0.1 parts; The coupling agent comprises 10 to 25 parts by weight of an acrylic acid-modified aminosilane oligomer; The raw materials for the acrylic acid-modified aminosilane oligomer include an aminosilane coupling agent and an acrylic acid compound in a mass ratio of (12-18):

1.

2. The acid mist resistant two-component silicone structural adhesive according to claim 1, characterized in that, The aminosilane coupling agent includes one or a combination of several of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane, and 3-diethylenetriaminopropylmethyldimethoxysilane.

3. The acid mist resistant two-component silicone structural adhesive according to claim 1, characterized in that, The acrylic compound comprises methacrylic acid and propylacrylic acid in a mass ratio of (1.5 to 2.5):

1.

4. The acid mist resistant two-component silicone structural adhesive according to claim 1, characterized in that, The acrylic acid-modified aminosilane oligomer was prepared by the following method: an aminosilane coupling agent was added to a solvent and mixed evenly to obtain a mixed solution. A catalyst was added to the mixed solution, and after heating to 40-60°C, deionized water was added. The temperature was raised to 90-110°C with stirring, and the reaction was carried out for 3-5 hours to obtain a pre-reactant. The temperature of the pre-reactant was adjusted to 40-60°C, an acrylic acid compound was added, and after reacting for 3-6 hours, the acrylic acid-modified aminosilane oligomer was obtained by vacuum distillation.

5. The acid mist resistant two-component silicone structural adhesive according to claim 1, characterized in that, The B component raw material also includes 2 to 5 parts by weight of graphene oxide; the oxygen content of the graphene oxide is 30 to 40%.

6. The acid mist resistant two-component silicone structural adhesive according to claim 1, characterized in that, The coupling agent further includes one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropyltriethoxysilane, γ-glycidyl etheroxypropylmethyldiethoxysilane, γ-glycidyl etheroxypropylmethyldiethoxysilane, 3-diethylenetriaminopropyltrimethoxysilane, and 3-cyclopentadienylpropyltriethoxysilane.

7. The acid mist resistant two-component silicone structural adhesive according to claim 1, characterized in that, The catalyst includes one or more of dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, and stannous octoate.

8. The acid mist resistant two-component silicone structural adhesive according to claim 1, characterized in that, The mass ratio of component A to component B is (7-11):

1.

9. A method for preparing an acid mist resistant two-component silicone structural adhesive according to any one of claims 1 to 8, characterized in that, It is prepared by the following steps: Preparation of component A: After adding 107 base glue, filler and dimethyl silicone oil to the reaction vessel, stir for 1 to 3 hours under vacuum at 120 to 160°C to obtain component A; Preparation of component B: Carbon black and dimethyl silicone oil are mixed evenly and added to a reaction vessel. The mixture is stirred under vacuum at 140-160°C for 10-20 minutes. Crosslinking agent, fumed silica and graphene oxide are added sequentially and stirred under vacuum for 20-40 minutes. Finally, coupling agent and catalyst are added and stirred under vacuum for 50-70 minutes to obtain component B.

Images