Single-component modified inorganic high-temperature-resistant structural adhesive and preparation method thereof

Abstract

The invention relates to the technical field of high-temperature-resistant adhesives, in particular to a single-component modified inorganic high-temperature-resistant structural adhesive and a preparation method thereof. The single-component modified inorganic high-temperature-resistant structural adhesive provided by the invention is prepared from the following raw materials in parts by mass: 25 to 50 parts of water glass, 15 to 35 parts of aluminum oxide, 10 to 30 parts of silica powder, 5 to 10 parts of mica powder, 10 to 30 parts of modified aluminum powder, 1 to 3 parts of silicon carbide whiskers, 3 to 5 parts of octahydroxy butylated cage-shaped polysilsesquioxane and 0.5 to 1 part of tetramethyl ammonium cage-shaped polysilsesquioxane. The high-temperature-resistant adhesive provided by the invention solves the problem that the existing inorganic high-temperature-resistant adhesive is not resistant to mechanical impact or violent temperature change, and also solves the problem that the single-component silicate high-temperature adhesive is short in storage time.

Description

Technical Field

[0001] This application relates to the field of high-temperature resistant adhesives, and in particular to a single-component modified inorganic high-temperature resistant structural adhesive and its preparation method. Background Technology

[0002] High-temperature structural adhesives, as adhesives that can maintain their physicochemical properties stably for a long time in high-temperature environments, have wide applications in industries such as industry, aerospace, and electronics. Based on their composition, high-temperature structural adhesives can be divided into two main categories: organic and inorganic.

[0003] Organic high-temperature resistant adhesives mainly include epoxy resins, phenolic resins, silicones, and heterocyclic compounds. They typically possess excellent bonding strength and impact resistance, but most types of organic adhesives can only be used in environments below 300°C. When the temperature is too high, the molecular chains of these materials may break, causing the adhesive to decompose and carbonize, thus losing its bonding ability.

[0004] In contrast, inorganic high-temperature adhesives such as silicates, phosphates, borates, and sulfates can withstand much higher temperatures (typically exceeding 800°C) and are resistant to open flame combustion. However, these adhesives generally suffer from low bond strength, and due to their hard and brittle nature and low coefficient of thermal expansion, they are not resistant to mechanical impact or drastic temperature changes. For example, patent CN116554790A discloses a high-temperature resistant adhesive, its preparation method, and its application. This patent mixes an aluminosilicate-containing base material, an alkali activator, water, and high-temperature resistant particles in a specific ratio to prepare a high-temperature resistant adhesive. The adhesive maintains good mechanical properties and performance even at operating temperatures up to 700°C. However, this adhesive does not involve performance testing under drastic temperature changes.

[0005] Based on the above analysis, it is essential to provide a structural adhesive that can withstand both high temperatures and thermal shock. Summary of the Invention

[0006] This application provides a one-component modified inorganic high-temperature resistant structural adhesive to solve the problem that existing inorganic high-temperature resistant adhesives in the related art are not resistant to mechanical impact or drastic temperature changes, and at the same time solve the problem of short storage time of one-component silicate high-temperature adhesives.

[0007] In one aspect, this application provides a single-component modified inorganic high-temperature resistant structural adhesive, comprising the following raw materials by weight: 25-50 parts water glass, 15-35 parts aluminum oxide, 10-30 parts silica powder, 5-10 parts mica powder, 10-30 parts modified aluminum powder, 1-3 parts silicon carbide whiskers, 3-5 parts octahydroxybutylated cage-like polysilsesquioxane, and 0.5-1 part tetramethylammonium cage-like polysilsesquioxane.

[0008] In some embodiments, the modified aluminum powder is prepared by the following process: dilute nitric acid is added to spherical aluminum powder for etching for 5-8 minutes, followed by washing with deionized water until the pH of the system is 6.0-7.0, and then anhydrous ethanol is added for washing to obtain pretreated spherical aluminum powder; polyvinylpyrrolidone is added to the pretreated spherical aluminum powder, ultrasonically dispersed, and after uniform dispersion, heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane and dibutyltin dilaurate are added, and the mixture is heated and stirred at 70-80°C under nitrogen protection. After the reaction is completed, the mixture is filtered and dried to obtain the modified aluminum powder.

[0009] In some embodiments, the concentration of the dilute nitric acid is 1.0~1.5 mol / L, and the amount of polyvinylpyrrolidone added is 0.5%~1% of the mass of the spherical aluminum powder.

[0010] In some embodiments, the liquid-to-solid ratio of dilute nitric acid to spherical aluminum powder is 3:1 to 5:1 mL / g.

[0011] In some embodiments, the amount of heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane added is 1% to 3% of the mass of spherical aluminum powder; the amount of dibutyltin dilaurate added is 0.2% to 0.6% of the mass of heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane.

[0012] In some embodiments, the drying process involves first drying at 60°C for 1-2 hours, then heating to 80°C at a rate of 2°C / min for 1-2 hours, and finally heating to 110°C at a rate of 3°C / min for 2-3 hours.

[0013] In some embodiments, the water glass is one or more of sodium water glass and potassium water glass, with a modulus of 2.8 to 3.6.

[0014] In some embodiments, the aluminum oxide is spherical or near-spherical with a particle size of 10-25 μm.

[0015] In some embodiments, the silicon micropowder has a particle size of 8~20μm.

[0016] In some embodiments, the mica powder is synthetic mica with a particle size of 10~40μm.

[0017] In some embodiments, the silicon carbide whiskers have a diameter of 0.1 to 2.5 μm and a length of 10 to 50 μm.

[0018] In some embodiments, the structural formula of heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane is as follows: .

[0019] In some embodiments, the structural formula of the octahydroxybutylated cage-like polysilsesquioxane is as follows: ; Octylbutylated cage-like polysilsesquioxane is a POSS with eight hydroxyl groups on the outer layer. It has the basic properties of POSS, such as high strength and high temperature resistance, as well as the toughness of organosilicon resin. At the same time, the eight hydroxyl groups on the periphery also have high reactivity.

[0020] In some embodiments, the structural formula of the tetramethylammonium cage-type polysilsesquioxane is as follows: .

[0021] Secondly, this application provides a method for preparing a one-component modified inorganic high-temperature resistant structural adhesive, comprising the following steps: S101, aluminum oxide, silicon micro powder, mica powder, modified aluminum powder, and silicon carbide whiskers are initially mixed to obtain the first mixture; S102, add water glass and tetramethylammonium cage-type polysilsesquioxane to the first mixture and stir and disperse at high speed. The dispersion speed is 2000-2500 rpm and the time is 10-20 min. The temperature of the material is controlled to be less than 45℃ to obtain the second mixture. S103, add octahydroxybutylated cage-like polysilsesquioxane to the second mixture, continue high-speed dispersion at a speed of 2000-2500 rpm for 20-30 min, and control the temperature of the material to be less than 45℃. After uniform dispersion, a semi-flowing paste-like liquid is formed. Cool to room temperature to obtain the modified inorganic high-temperature resistant structural adhesive.

[0022] The beneficial effects of the technical solution provided in this application include: 1. Traditional high-temperature structural adhesives based on aluminosilicates are generally two-component, with liquid water glass and powder stored separately and prepared on-site before use. While one-component high-temperature structural adhesives based on aluminosilicates are convenient to use, they generally suffer from poor storage stability, requiring refrigeration. At room temperature, they gradually gel or structure, becoming unusable. This is because water glass has high reactivity and readily reacts with some highly reactive powders, especially at high temperatures, causing rapid deterioration of the adhesive. The high-temperature structural adhesive prepared in this application incorporates aluminum powder. Its advantage lies in the fact that the highly reactive aluminum powder reacts with water glass during curing to form xSiO2·yAl2O3 aluminosilicate crystals, resulting in high cohesive strength. Simultaneously, after the aluminum powder forms aluminosilicate on its surface, the interior remains metallic aluminum, providing flexibility and thermal conductivity, thus improving the adhesive's impact resistance and heat resistance. However, in this application's one-component formulation, the aluminum powder needs to be dispersed in water glass. During preparation and storage, due to the high reactivity of the aluminum powder surface, it reacts with OH groups in the water glass. -Ions undergo certain reactions, leading to severe structuring of aluminum powder during storage and causing deterioration of the adhesive. Therefore, this application utilizes heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane to modify aluminum powder. Heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane contains three silanol groups. Aluminum reacts with the hydroxyl groups in the silanol groups, oxidizing Al to Al. 3+ It combines with siloxy groups, that is, aluminum atoms are connected to three silicon atoms of cage-shaped polysilsesquioxane through oxygen bridges, thereby grafting semi-condensed POSS onto the surface of aluminum powder to form a semi-organic shielding layer with high strength, reducing the reaction with water glass. In a high-temperature environment, the organic groups will gradually decompose, and the exposed Si-O- can react with Si-OH in water glass to continue to generate aluminosilicate crystal structure. 2. The modified inorganic high-temperature resistant structural adhesive prepared in this application is doped with octahydroxybutylated cage-like polysilsesquioxane and an inorganic salt system. During the curing process, the hydroxyl groups on the periphery of the octahydroxybutylated cage-like polysilsesquioxane can undergo a condensation reaction with water glass, which can form a bridge between powder particles, reduce the brittleness of the adhesive, and enhance its impact toughness, so that the adhesive is not easy to break when subjected to mechanical impact or thermal shock. 3. The modified aluminum powder has certain organic groups grafted onto its surface, which gives it a certain degree of hydrophobicity and poor dispersibility in water glass solution. Meanwhile, octahydroxybutylated cage-like polysilsesquioxane is immiscible with water. This application improves the dispersibility of modified aluminum powder and the compatibility of octahydroxybutylated cage-like polysilsesquioxane by adding tetramethylammonium cage-like polysilsesquioxane, which is a cationic surfactant with a POSS structure. This results in a more uniform dispersion of the adhesive and makes it less prone to stratification. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the inorganic high-temperature resistant structural adhesive prepared in Example 1 of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] The embodiments of this application provide solutions to problems in the prior art.

[0027] Example 1: Preparation of modified aluminum powder: 700 mL of 1.5 mol / L dilute nitric acid was added to 200 g of spherical aluminum powder with a particle size of 5 μm for etching for 6 min. The powder was then washed with deionized water until the pH of the system reached 6.0–7.0, followed by washing with anhydrous ethanol to obtain pretreated spherical aluminum powder. Then, 0.5% (by weight) of polyvinylpyrrolidone (PVP) was added to the spherical aluminum powder, and the mixture was ultrasonically dispersed for 35 min. After uniform dispersion, 2% (by weight) of heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane and heptaisobutyltrisilyltrisilyltrisiloxane were added. 0.3% by mass of isobutyltrisilyl alcohol cage-like polysilsesquioxane and dibutyltin dilaurate were heated and stirred in a nitrogen atmosphere using a reflux condenser at 80°C for 4 hours. After stirring was stopped, the dispersion was filtered using a vacuum filter, and then dried in a nitrogen atmosphere at 60°C for 1 hour. The temperature was then increased to 80°C at a rate of 2°C / min and dried for 1 hour. Finally, the temperature was increased to 110°C at a rate of 3°C / min and dried for 3 hours to obtain modified aluminum powder with a particle size of 5 μm.

[0028] Preparation of high-temperature resistant structural adhesives: 110g of spherical alumina with a particle size of 15μm, 90g of silicon micro powder with a particle size of 10μm, 25g of synthetic mica powder with a particle size of 25μm, 100g of modified aluminum powder with a particle size of 5μm, and 10g of silicon carbide whiskers with a diameter of 1μm and a length of 40μm were premixed to obtain the first mixture. Add 140g of sodium silicate with a modulus of 3.4 and 5g of tetramethylammonium cage-type polysilsesquioxane to the first mixture, stir in a sealed reactor, disperse at 2000rpm for 20min, turn on the cooling equipment, and control the temperature of the material to be less than 45℃. Add 20g of octahydroxybutylated cage-like polysilsesquioxane to the reactor and disperse it at 2000rpm for 15min, while controlling the material temperature to be less than 45℃. After uniform dispersion, a fine, semi-flowing paste-like liquid is formed. After cooling to room temperature, the modified inorganic high-temperature resistant structural adhesive is obtained.

[0029] The modified inorganic high-temperature resistant structural adhesive prepared in Example 1 is shown in [reference needed]. Figure 1 ,from Figure 1 As can be seen, the structural adhesive is a gray, fine, semi-flowing paste-like liquid.

[0030] Example 2: Preparation of modified aluminum powder: 650 mL of 1.2 mol / L dilute nitric acid was added to 200 g of spherical aluminum powder with a particle size of 6 μm for etching for 8 min. The powder was then washed with deionized water until the pH reached 6.0–7.0, followed by washing with anhydrous ethanol to obtain pretreated spherical aluminum powder. Then, 0.6% (by weight) of polyvinylpyrrolidone (PVP) was added, and the mixture was ultrasonically dispersed for 30 min. After uniform dispersion, 2.5% (by weight) of heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane and heptaisobutyltrisilyltrisiloxane were added. 0.2% by mass of isobutyltrisilyl alcohol cage-like polysilsesquioxane and dibutyltin dilaurate were heated and stirred in a nitrogen atmosphere using a reflux condenser at 75°C for 6 hours. After stirring was stopped, the dispersion was filtered using a vacuum filter, and then dried in a nitrogen atmosphere at 60°C for 1 hour. The temperature was then increased to 80°C at a rate of 2°C / min and dried for 1.5 hours. Finally, the temperature was increased to 110°C at a rate of 3°C / min and dried for 2 hours to obtain modified aluminum powder with a particle size of 6 μm.

[0031] Preparation of high-temperature resistant structural adhesives: 125g of spherical alumina with a particle size of 10μm, 70g of silicon micro powder with a particle size of 12μm, 30g of synthetic mica powder with a particle size of 15μm, 80g of modified aluminum powder with a particle size of 6μm, and 7.5g of silicon carbide whiskers with a diameter of 1μm and a length of 40μm were premixed to obtain the first mixture. Add 160g of sodium silicate with a modulus of 3.0 and 2.5g of tetramethylammonium cage-type polysilsesquioxane to the first mixture, stir in a sealed reactor, disperse at 2500rpm for 10min, turn on the cooling equipment, and control the temperature of the material to be less than 45℃. Add 25g of octahydroxybutylated cage-like polysilsesquioxane to the reactor and disperse it at 2000rpm for 20min, while controlling the material temperature to be less than 45℃. After uniform dispersion, a fine, semi-flowing paste-like liquid is formed. After cooling to room temperature, the modified inorganic high-temperature resistant structural adhesive is obtained.

[0032] Example 3: Preparation of modified aluminum powder: 800 mL of 1.0 mol / L dilute nitric acid was added to 200 g of spherical aluminum powder with a particle size of 8 μm for etching for 8 min. The powder was then washed with deionized water until the pH reached 6.0-7.0, followed by washing with anhydrous ethanol to obtain pretreated spherical aluminum powder. Then, 0.8% (by weight) of polyvinylpyrrolidone (PVP) was added, and the mixture was ultrasonically dispersed for 35 min. After uniform dispersion, 1.5% (by weight) of heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane and... 0.5% by mass of heptaisobutyltrisilyl silsesquioxane cage-like polysilsesquioxane and dibutyltin dilaurate were heated and stirred in a nitrogen atmosphere using a reflux condenser at 78°C for 4 hours. After stirring was stopped, the dispersion was filtered using a vacuum filter, and then dried in a nitrogen atmosphere at 60°C for 1 hour. The temperature was then increased to 80°C at a rate of 2°C / min and dried for 2 hours. Finally, the temperature was increased to 110°C at a rate of 3°C / min and dried for 2 hours to obtain modified aluminum powder with a particle size of 8 μm.

[0033] Preparation of high-temperature resistant structural adhesives: 260g of spherical alumina with a particle size of 22μm, 204g of silicon micro powder with a particle size of 8μm, 70g of synthetic mica powder with a particle size of 30μm, 130g of modified aluminum powder with a particle size of 8μm, and 25g of silicon carbide whiskers with a diameter of 2μm and a length of 50μm were premixed to obtain the first mixture. Add 270g of sodium silicate with a modulus of 3.4 and 6g of tetramethylammonium cage-type polysilsesquioxane to the first mixture, stir in a sealed reactor, disperse at 2000rpm for 15min, turn on the cooling equipment, and control the temperature of the material to be less than 45℃. Add 35g of octahydroxybutylated cage-like polysilsesquioxane to the reactor and disperse it at 2000rpm for 15min, while controlling the material temperature to be less than 45℃. After uniform dispersion, a fine, semi-flowing paste-like liquid is formed. After cooling to room temperature, the modified inorganic high-temperature resistant structural adhesive is obtained.

[0034] Example 4: Preparation of modified aluminum powder: 750 mL of 1.5 mol / L dilute nitric acid was added to 200 g of spherical aluminum powder with a particle size of 9 μm for etching for 6 min. The powder was then washed with deionized water until the pH reached 6.0-7.0, followed by washing with anhydrous ethanol to obtain pretreated spherical aluminum powder. Then, 1% (by weight) of polyvinylpyrrolidone (PVP) was added, and the mixture was ultrasonically dispersed for 30 min. After uniform dispersion, 3% (by weight) of heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane and heptaisobutyltrisilyl ether were added. Modified aluminum powder with a particle size of 9 μm was obtained by heating and stirring a reflux condenser under a nitrogen atmosphere with 0.6% by mass of trisilyl chloride cage-like polysilsesquioxane and dibutyltin dilaurate under a nitrogen atmosphere at a controlled temperature of 75 °C for 4 h. After stirring was stopped, the dispersion was filtered using a vacuum filter, and then dried at 60 °C for 1.5 h under a nitrogen atmosphere. The temperature was then increased to 80 °C at a rate of 2 °C / min and dried for 2 h. Finally, the temperature was increased to 110 °C at a rate of 3 °C / min and dried for 2 h.

[0035] Preparation of high-temperature resistant structural adhesives: 180g of spherical alumina with a particle size of 18μm, 160g of silicon micro powder with a particle size of 12μm, 82g of synthetic mica powder with a particle size of 10μm, 120g of modified aluminum powder with a particle size of 9μm, and 10g of silicon carbide whiskers with a diameter of 2.5μm and a length of 30μm were premixed to obtain the first mixture; Add 400g of sodium silicate with a modulus of 3.2 and 8g of tetramethylammonium cage-type polysilsesquioxane to the first mixture, stir in a sealed reactor, disperse at 2500rpm for 15min, turn on the cooling equipment, and control the temperature of the material to be less than 45℃. Add 40g of octahydroxybutylated cage-like polysilsesquioxane to the reactor and disperse it at 2000rpm for 20min, while controlling the material temperature to be less than 45℃. After uniform dispersion, a fine, semi-flowing paste-like liquid is formed. After cooling to room temperature, the modified inorganic high-temperature resistant structural adhesive is obtained.

[0036] Example 5: Preparation of modified aluminum powder: 600 mL of 1.5 mol / L dilute nitric acid was added to 200 g of spherical aluminum powder with a particle size of 6 μm for etching for 8 min. The powder was then washed with deionized water until the pH reached 6.0-7.0, followed by washing with anhydrous ethanol to obtain pretreated spherical aluminum powder. Then, 0.8% (by weight) of polyvinylpyrrolidone (PVP) was added, and the mixture was ultrasonically dispersed for 35 min. After uniform dispersion, 2.5% (by weight) of heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane and heptaisobutyltrisilyltrisilyltrisiloxane were added. The modified aluminum powder with a particle size of 6 μm was obtained by heating and stirring in a nitrogen atmosphere using a reflux condenser with 0.4% isobutyltrisilyl alcohol cage-like polysilsesquioxane and dibutyltin dilaurate under a nitrogen atmosphere and a reflux condenser at 80 °C for 4 h. After stirring was stopped, the dispersion was filtered using a vacuum filter and then dried in a nitrogen atmosphere at 60 °C for 1 h, then heated to 80 °C at a heating rate of 2 °C / min and dried for 1.5 h, and finally heated to 110 °C at a heating rate of 3 °C / min and dried for 2 h.

[0037] Preparation of high-temperature resistant structural adhesives: 250g of spherical alumina with a particle size of 25μm, 195g of silicon micro powder with a particle size of 10μm, 60g of synthetic mica powder with a particle size of 25μm, 100g of modified aluminum powder with a particle size of 6μm, and 25g of silicon carbide whiskers with a diameter of 2μm and a length of 50μm were premixed to obtain the first mixture. Add 330g of sodium silicate with a modulus of 3.4 and 5g of tetramethylammonium cage-type polysilsesquioxane to the first mixture, stir in a sealed reactor, disperse at 2000rpm for 10min, turn on the cooling equipment, and control the temperature of the material to be less than 45℃. Add 35g of octahydroxybutylated cage-like polysilsesquioxane to the reactor and disperse it at 2500rpm for 15min, while controlling the material temperature to be less than 45℃. After uniform dispersion, a fine, semi-flowing paste-like liquid is formed. After cooling to room temperature, the modified inorganic high-temperature resistant structural adhesive is obtained.

[0038] Example 6: Preparation of modified aluminum powder: 800 mL of 1.2 mol / L dilute nitric acid was added to 200 g of spherical aluminum powder with a particle size of 5 μm for etching for 6 min. The powder was then washed with deionized water until the pH reached 6.0-7.0, followed by washing with anhydrous ethanol to obtain pretreated spherical aluminum powder. Then, 0.6% (by weight) of polyvinylpyrrolidone (PVP) was added to the spherical aluminum powder, and the mixture was ultrasonically dispersed for 30 min. After uniform dispersion, 3% (by weight) of heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane and heptaisobutyltrisilyl ether were added. Modified aluminum powder with a particle size of 5 μm was obtained by heating and stirring a reflux condenser under a nitrogen atmosphere with 0.5% by mass of trisilyl chloride cage-like polysilsesquioxane and dibutyltin dilaurate under a nitrogen atmosphere at 80 °C for 4 hours. After stirring was stopped, the dispersion was filtered using a vacuum filter, and then dried at 60 °C for 1.5 hours under a nitrogen atmosphere. The temperature was then increased to 80 °C at a rate of 2 °C / min and dried for 2 hours. Finally, the temperature was increased to 110 °C at a rate of 3 °C / min and dried for 2.5 hours.

[0039] Preparation of high-temperature resistant structural adhesives: 280g of spherical alumina with a particle size of 10μm, 150g of silicon micro powder with a particle size of 20μm, 60g of synthetic mica powder with a particle size of 20μm, 120g of modified aluminum powder with a particle size of 5μm, and 30g of silicon carbide whiskers with a diameter of 2.5μm and a length of 40μm were premixed to obtain the first mixture. Add 315g of sodium silicate with a modulus of 3.4 and 10g of tetramethylammonium cage-type polysilsesquioxane to the first mixture, stir in a sealed reactor, disperse at 2000rpm for 20min, turn on the cooling equipment, and control the temperature of the material to be less than 45℃. Add 35g of octahydroxybutylated cage-like polysilsesquioxane to the reactor and disperse it at 2000rpm for 20min, while controlling the material temperature to be less than 45℃. After uniform dispersion, a fine, semi-flowing paste-like liquid is formed. After cooling to room temperature, the modified inorganic high-temperature resistant structural adhesive is obtained.

[0040] Comparative Example 1: The only difference between Comparative Example 1 and Example 1 is that the aluminum powder is not modified; the rest of the process is the same as in Example 1.

[0041] Comparative Example 2: The modified aluminum powder used in Comparative Example 2 was the same as that used in Example 1.

[0042] Preparation of high-temperature resistant structural adhesives: 110g of spherical alumina with a particle size of 15μm, 90g of silicon micro powder with a particle size of 10μm, 25g of synthetic mica powder with a particle size of 25μm, 100g of modified aluminum powder with a particle size of 5μm, and 10g of silicon carbide whiskers with a diameter of 1μm and a length of 40μm were premixed to obtain the first mixture. 140g of sodium silicate with a modulus of 3.4 and 5g of tetramethylammonium cage-type polysilsesquioxane were added to the first mixture and stirred in a sealed reactor. The mixture was dispersed at 2000 rpm for 20 minutes. The cooling equipment was turned on to control the temperature of the material to be less than 45℃, thus obtaining a single-component modified inorganic high-temperature resistant structural adhesive.

[0043] Comparative Example 3: The modified aluminum powder used in Comparative Example 3 was the same as that used in Example 1.

[0044] Preparation of high-temperature resistant structural adhesives: 110g of spherical alumina with a particle size of 15μm, 90g of silicon micro powder with a particle size of 10μm, 25g of synthetic mica powder with a particle size of 25μm, 100g of modified aluminum powder with a particle size of 5μm, and 10g of silicon carbide whiskers with a diameter of 1μm and a length of 40μm were premixed to obtain the first mixture. Add 140g of sodium silicate with a modulus of 3.4 to the first mixture, stir in a sealed reactor, disperse at 2000rpm for 20min, turn on the cooling equipment, and control the temperature of the material to be below 45℃; 20g of octahydroxybutylated cage-like polysilsesquioxane was added to a reactor and dispersed at 2000rpm for 15min, while controlling the material temperature to be below 45℃, to obtain a one-component modified inorganic high-temperature resistant structural adhesive. The performance of the high-temperature resistant structural adhesives prepared in Examples 1-6 and Comparative Examples 1-3 was tested, and the results are shown in Table 1.

[0045] In Table 1, the process of fitting copper metal rings is as follows: the prepared structural adhesive is applied to the inner side of the outer ring of the copper metal ring, and then the inner ring of the copper metal ring is fitted onto the outer ring.

[0046] Table 1: Performance test results of the high-temperature resistant structural adhesives prepared in Examples 1-6 and Comparative Examples 1-3 ; As can be seen from the data in Table 1, the high-temperature resistant structural adhesive without modified aluminum powder is prone to gelation and deterioration during room temperature storage, resulting in poor storage stability; the high-temperature resistant structural adhesive without octahydroxybutylated cage-like polysilsesquioxane has poor toughness, and its shear strength is significantly reduced after high temperature, making it more prone to cracking and detachment during thermal shock testing; the high-temperature resistant structural adhesive without tetramethylammonium cage-like polysilsesquioxane cannot be evenly dispersed, and the adhesive exhibits stratification in its initial state, rendering it unusable.

[0047] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0048] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0049] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A one-component modified inorganic high-temperature resistant structural adhesive, characterized in that, By weight, it includes the following raw materials: 25-50 parts water glass, 15-35 parts aluminum oxide, 10-30 parts silica powder, 5-10 parts mica powder, 10-30 parts modified aluminum powder, 1-3 parts silicon carbide whiskers, 3-5 parts octahydroxybutylated cage-like polysilsesquioxane, and 0.5-1 part tetramethylammonium cage-like polysilsesquioxane.

2. The single-component modified inorganic high-temperature resistant structural adhesive according to claim 1, characterized in that, The modified aluminum powder is prepared by the following process: dilute nitric acid is added to spherical aluminum powder for etching, followed by washing with deionized water until the pH of the system is 6.0~7.0, and then anhydrous ethanol is added for washing to obtain pretreated spherical aluminum powder; polyvinylpyrrolidone is added to the pretreated spherical aluminum powder, and ultrasonically dispersed. After uniform dispersion, heptaisobutyltrisilyl alcohol cage-like polysilsesquioxane and dibutyltin dilaurate are added, and the mixture is heated and stirred under nitrogen protection. After the reaction is completed, the mixture is filtered and dried to obtain the modified aluminum powder.

3. The single-component modified inorganic high-temperature resistant structural adhesive according to claim 2, characterized in that, The concentration of the dilute nitric acid is 1.0~1.5 mol / L, and the amount of polyvinylpyrrolidone added is 0.5%~1% of the mass of the spherical aluminum powder.

4. The single-component modified inorganic high-temperature resistant structural adhesive according to claim 2, characterized in that, The amount of heptaisobutyltrisilyl alcohol cage-shaped polysilsesquioxane added is 1% to 3% of the mass of spherical aluminum powder; the amount of dibutyltin dilaurate added is 0.2% to 0.6% of the mass of heptaisobutyltrisilyl alcohol cage-shaped polysilsesquioxane.

5. The single-component modified inorganic high-temperature resistant structural adhesive according to claim 1, characterized in that, The water glass is one or more of sodium water glass and potassium water glass, with a modulus of 2.8 to 3.

6.

6. The single-component modified inorganic high-temperature resistant structural adhesive according to claim 1, characterized in that, The aluminum oxide is spherical or near-spherical with a particle size of 10~25μm.

7. The single-component modified inorganic high-temperature resistant structural adhesive according to claim 1, characterized in that, The particle size of the silicon micropowder is 8~20μm.

8. The single-component modified inorganic high-temperature resistant structural adhesive according to claim 1, characterized in that, The mica powder is synthetic mica with a particle size of 10~40μm.

9. The single-component modified inorganic high-temperature resistant structural adhesive according to claim 1, characterized in that, The silicon carbide whiskers have a diameter of 0.1~2.5μm and a length of 10~50μm.

10. A method for preparing the single-component modified inorganic high-temperature resistant structural adhesive according to any one of claims 1-9, characterized in that, Includes the following steps: S101, aluminum oxide, silicon micro powder, mica powder, modified aluminum powder, and silicon carbide whiskers are initially mixed to obtain the first mixture; S102, add water glass and tetramethylammonium cage-type polysilsesquioxane to the first mixture and stir and disperse at high speed, controlling the temperature of the material to be less than 45°C, to obtain the second mixture; S103, add octahydroxybutylated cage-like polysilsesquioxane to the second mixture, continue high-speed dispersion, and control the temperature of the material to be less than 45°C. After uniform dispersion, a semi-flowing paste-like liquid is formed. Cool to room temperature to obtain the modified inorganic high-temperature resistant structural adhesive.

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