A hyperbranched polymer polyzirconium aluminum borosiloxane, and a preparation method and application thereof

Abstract

The application discloses a hyperbranched polymer poly-zirconium-aluminum-boron-siloxane, a preparation method and application thereof, and belongs to the technical field of high polymer compounds, and the preparation method comprises the following steps: dissolving a zirconium source and a chelating agent in an organic solvent, stirring, and obtaining a zirconium-chelating agent complex solution; dissolving aluminum isopropyl alcohol and boric acid in an organic solvent, adding glacial acetic acid, uniformly stirring, and obtaining a boron-aluminum composite solution; uniformly mixing the zirconium-chelating agent complex solution and the boron-aluminum composite solution, obtaining a zirconium-boron-aluminum mixed precursor solution, then adding methyltrimethoxysilane into the zirconium-boron-aluminum mixed precursor solution, reacting, removing the organic solvent by rotary evaporation, and obtaining the poly-zirconium-aluminum-boron-siloxane. That is, the application provides a synergistically modified poly-zirconium-aluminum-boron-siloxane, the introduction of zirconium elements improves the temperature resistance of a resin skeleton, meanwhile, the resin can form a glass phase in situ at high temperature through boron-aluminum modification, plays a bonding and protection role, and overcomes the limitation of a single modified element.

Description

Technical Field

[0001] This invention belongs to the field of polymer compound technology, and particularly relates to a hyperbranched polymer polyzirconium aluminum borosilicate, its preparation method and application. Background Technology

[0002] Silicone resins, due to their unique Si-O main chain structure, exhibit better temperature resistance compared to carbon-chain polymers, allowing for long-term use at temperatures ranging from -60℃ to 300℃. Therefore, they are widely used as the resin matrix for high-temperature composite adhesives. With the rapid development of the aerospace industry, adhesive bonding, due to its convenient and efficient characteristics, has been widely used in the assembly and manufacturing of high-temperature alloy connectors for high-temperature working parts of hypersonic vehicles. However, the mechanical property degradation and thermo-oxidative aging problems of silicone resin adhesives under high-temperature conditions (>300℃) severely restrict their long-term service reliability. Existing modification methods (such as adding heat-resistant fillers, metal oxides, fibers, etc.) struggle to balance mechanical properties and thermal stability, and high filler content easily leads to poor compatibility, deteriorated processing performance, and increased material hardness. Introducing heteroatoms or large rigid groups (phenyl, POSS, etc.) through main chain or side chain organosilicon molecule modification technology is a key research direction for improving the heat resistance of silicone resins. Rational design of the type, position, and content of rigid groups can achieve an optimized balance between high-temperature resistance and comprehensive mechanical properties. However, the complex synthesis steps and harsh reaction conditions of organosilicon macromolecules, such as Grignard reactions, limit their large-scale promotion and application. For example, the synthesis steps of modified silicone resins are complex and demanding, generally requiring oxygen-free, high-temperature, high-pressure catalysts. Moreover, they can only increase the bonding temperature of silicone resin-based adhesives to a certain extent (e.g., below 100°C), and cannot fundamentally solve the bonding problem of silicone resin-based adhesives under extreme thermal environments. The only way to achieve an adhesive effect is by adding inorganic additives (ceramic powder, glass powder).

[0003] Therefore, there is an urgent need to provide a modified silicone resin-based adhesive that combines high heat resistance, excellent high-temperature bonding strength, and good processability, as well as a simple and feasible preparation method therein. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a hyperbranched polymer polyzirconium aluminum borosilicate, its preparation method, and its applications.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing a hyperbranched polymer polyzirconium aluminum borosilicate includes the following steps:

[0007] (1) Dissolve the zirconium source and chelating agent in an organic solvent and stir to obtain a zirconium-chelating agent complex solution;

[0008] (2) Dissolve aluminum isopropoxide and boric acid in an organic solvent, add glacial acetic acid, and stir until homogeneous to obtain a boron-aluminum composite solution;

[0009] (3) The zirconium-chelating agent complex solution and the boron-aluminum composite solution are mixed evenly to obtain a zirconium-boron-aluminum mixed precursor solution. Then, methyltrimethoxysilane is added to it, and the reaction is carried out. Then, the organic solvent is removed by rotary evaporation to obtain a uniform and transparent polyzirconium aluminum borosiloxane.

[0010] Optionally, the zirconium source is zirconium oxychloride octahydrate.

[0011] Optionally, the organic solvent is anhydrous ethanol.

[0012] Optionally, the chelating agent is selected from acetylacetone, acetic acid, dibenzoylmethane, citric acid, or ethylenediaminetetraacetic acid.

[0013] Optionally, the mass ratio of the zirconium source to the chelating agent is (6.3-12.8):3.

[0014] Optionally, in step (1), the stirring temperature is 40-50℃.

[0015] Optionally, the mass ratio of the zirconium source, aluminum isopropoxide, boric acid and methyltrimethoxysilane is (6.3-12.8):3:2:(5-15).

[0016] Optionally, the amount of glacial acetic acid added is 2-5 wt.% of the boron-aluminum composite solution.

[0017] Optionally, the reaction conditions in step (3) are: react at 50-70℃ for 3 h.

[0018] Optionally, the conditions for rotary evaporation in step (3) are: rotary evaporation at 100°C for 1 h.

[0019] A hyperbranched polymer, polyzirconium aluminum borosilicate, is prepared by the above-described preparation method.

[0020] The application of the aforementioned hyperbranched polymer polyzirconium aluminum borosiloxane in the preparation of high-temperature resistant modified silicone resin adhesives.

[0021] Optionally, the preparation process of the modified silicone resin adhesive is as follows:

[0022] The modified silicone resin adhesive is prepared by mixing the polyzirconium aluminum borosiloxane with a cyclohexane solution containing methyl silicone resin at a mass ratio of 1:1-2.

[0023] Furthermore, the mass concentration of the cyclohexane solution containing methyl silicone resin is 60%.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] 1. This invention provides a synergistically modified polyzirconium aluminum borosiloxane, which improves the temperature resistance of the resin skeleton by introducing zirconium, and enables the resin to form a glass phase in situ at high temperatures through boron and aluminum modification, thereby playing a bonding and protective role and overcoming the limitations of a single modifying element.

[0026] 2. By establishing a continuous high-temperature protection mechanism, the modified silicone resin binder can form an effective protective structure throughout the entire thermal decomposition process from low temperature to high temperature, significantly improving the thermal stability and high-temperature performance retention rate of the resin in the temperature range of 200-1200℃.

[0027] 3. This invention provides a simple and cost-effective method for preparing modified silicone resin adhesives, avoiding cumbersome reaction steps and expensive catalysts, thus ensuring that the modification method has prospects for industrial application.

[0028] 4. The modified silicone resin adhesive disclosed in this invention has excellent high-temperature durability and mechanical property stability, especially its ability to maintain performance under long-term high-temperature exposure conditions, which expands its application in extreme environments such as aerospace and missile materials. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 Infrared spectra comparison of modified silicone resin adhesive (Example 1) and methyl silicone resin (Comparative Example 1);

[0031] Figure 2 XPS data for the modified silicone adhesive prepared in Example 1;

[0032] Figure 3 The evolution of X-ray diffraction (XRD) patterns of the modified silicone resin adhesive in Example 1 during heat treatment from 200°C to 1200°C;

[0033] Figure 4 In Figure a, the TG-DSC curve of the modified silicone resin binder (Example 1) is shown in an oxygen atmosphere, and in Figure b, the TG-DSC curve of the methyl silicone resin (Comparative Example 1) is shown in an oxygen atmosphere. Detailed Implementation

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0035] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0036] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0037] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0038] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0039] This invention discloses a method for preparing hyperbranched polymer polyzirconium aluminum borosilicate, comprising the following steps:

[0040] (1) In a container, zirconium oxychloride octahydrate (ZrOCl2·8H2O) was dissolved in anhydrous ethanol and stirred continuously at room temperature to form a clear zirconium alkoxide solution; then acetylacetone was added as a chelating agent and stirred to generate a stable zirconium-acetylacetone complex solution.

[0041] (2) In another container, aluminum isopropoxide (Al(OCH(CH3)2)3) and boric acid (H3BO3) are dissolved together in anhydrous ethanol. Glacial acetic acid (CH3COOH) is added to the mixed solution, and the system is stirred gently to make it homogeneous, thus obtaining a boron-aluminum composite solution;

[0042] (3) The boron-aluminum composite solution prepared in step (2) is slowly added dropwise to the zirconium-acetylacetone complex solution prepared in step (1) under stirring, and mixed evenly to form a zirconium-boron-aluminum mixed precursor solution;

[0043] (4) Under stirring conditions, methyltrimethoxysilane (CH3Si(OCH3)3) was added dropwise to the zirconium-boron-aluminum mixed precursor solution; after the addition was complete, the reaction continued, and then rotary evaporation was performed to remove most of the ethanol solvent to form a uniform, transparent, light green polyzirconium aluminum borosiloxane; wherein the structural formula of polyzirconium aluminum borosiloxane is shown in Formula I.

[0044]

[0045] This invention discloses a hyperbranched polymer polyzirconium aluminum borosilicate, which is prepared by the above-described preparation method.

[0046] This invention discloses a modified silicone resin adhesive, the preparation process of which is as follows:

[0047] The prepared polyzirconium aluminum borosiloxane and a cyclohexane solution of 60% methyl silicone resin were mixed evenly at a mass ratio of 1:1 to prepare a modified silicone resin adhesive. The modified silicone resin adhesive has the structural formula shown in Formula II.

[0048]

[0049] This invention also discloses the application of the aforementioned hyperbranched polymer polyzirconium aluminum borosilicate in the preparation of high-temperature resistant silicone resin adhesives. The specific mechanism involved is as follows:

[0050] The polyzirconium aluminum borosilicate disclosed in this invention uses zirconium oxychloride octahydrate, aluminum isopropoxide, and boric acid as raw materials to provide zirconium, aluminum, and boron elements, respectively; acetylacetone and glacial acetic acid are used as chelating agents to regulate the hydrolysis rate, and the water of crystallization in zirconium oxychloride octahydrate is cleverly used as the endogenous water source for the hydrolysis reaction to achieve precise control of the hydrolysis process; anhydrous ethanol is used as an organic solvent and methyltrimethoxysilane is used as a silicon source to construct a hyperbranched polymer structure containing Si-OM (M=Al, B, Zr) bonds through a co-hydrolysis-condensation reaction.

[0051] When the prepared polyzirconium aluminum borosilicate siloxane is blended with methyl silicone resin, the abundant hydroxyl groups in its molecules can undergo condensation crosslinking with the silicone resin to form a polyzirconium aluminum borosilicate siloxane modified silicone resin binder. The Si-OM bond not only enhances the thermal stability of the silicone resin backbone, but also the zirconium, aluminum, and boron metals work synergistically during curing and high-temperature service: zirconium forms stable [ZrO] polyhedra with a high coordination number (6-8), acting as strong crosslinking points to anchor the siloxane network, and generating nano-zirconium oxide ceramic phase in situ at high temperatures, significantly enhancing the material's thermal stability and structural integrity; boron introduces high-bond-energy BO bonds with tricoordinate [BO3] planar units, promoting the formation of a dense, flowable borosilicate glass protective layer at high temperatures, effectively blocking oxygen and heat, and providing excellent anti-oxidation and pore-sealing effects; aluminum replaces silicon atoms isomorphically with tetracoordinate [AlO4] tetrahedra, strengthening the density and rigidity of the silicon-oxygen network and improving thermal stability in the mid-temperature range. The three mechanisms—ceramic reinforcement, glass sealing, and network densification—synergistically enhance the overall high-temperature resistance of the modified silicone resin binder.

[0052] Unless otherwise specified, "room temperature" in this invention refers to 20-30℃.

[0053] All raw materials used in this invention were purchased from the market.

[0054] The technical solution of the present invention will be further illustrated by the following embodiments.

[0055] Example 1

[0056] The specific process for preparing a modified silicone resin adhesive using polyzirconium aluminum borosiloxane is as follows:

[0057] (1) 10 mL of anhydrous ethanol was placed into the reaction vessel, and after the temperature was raised to 40°C, 9.6 g of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added. The mixture was stirred continuously at 40°C until a clear zirconium alkoxide solution was formed.

[0058] (2) Add 3 g of acetylacetone as a chelating agent to the zirconium alkoxide solution obtained in step (1) and stir continuously for 1 h to generate a stable zirconium-acetylacetone complex solution.

[0059] (3) In another reaction vessel, 3 g of aluminum isopropoxide (Al(OCH(CH3)2)3) and 2 g of boric acid (H3BO3) were dissolved together in 10 mL of anhydrous ethanol. Then, 2% of glacial acetic acid (CH3COOH) was added to the mixed solution and the system was stirred gently to make it homogeneous, thus obtaining a boron-aluminum composite solution.

[0060] (4) The boron-aluminum composite solution prepared in step (3) is slowly added dropwise to the zirconium-acetylacetone complex solution obtained in step (2) under stirring. After mixing evenly, a zirconium-boron-aluminum mixed precursor solution is formed.

[0061] (5) Heat the zirconium-boron-aluminum mixed precursor solution obtained in step (4) to 60°C and keep stirring. Add 10 g of methyltrimethoxysilane (CH3Si(OCH3)3) dropwise to it. After the addition is complete, continue the reaction at 60°C for 3 h.

[0062] (6) The reaction solution obtained in step (5) was rotary evaporated at 100°C for 1 h to remove most of the ethanol solvent, and finally a uniform, transparent light green polyzirconium aluminum borosilicate was obtained.

[0063] (7) The polyzirconium aluminum borosiloxane prepared in step (6) is mixed with a cyclohexane solution of methyl silicone resin with a solid content of 60% (the preparation process of the cyclohexane solution of methyl silicone resin with a solid content of 60% is the same as that in Comparative Example 1, and the following examples are similar) at a mass ratio of 1:2 to obtain the modified silicone resin adhesive.

[0064] Example 2

[0065] The specific process for preparing a modified silicone resin adhesive using polyzirconium aluminum borosiloxane is as follows:

[0066] (1) 10 mL of anhydrous ethanol was placed into the reaction vessel, and after the temperature was raised to 45°C, 9.6 g of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added. The mixture was stirred continuously at 45°C until a clear zirconium alkoxide solution was formed.

[0067] (2) Add 3 g of acetic acid as a chelating agent to the zirconium alkoxide solution obtained in step (1) and stir continuously for 1 h to generate a stable zirconium-acetic acid complex solution;

[0068] (3) In another reaction vessel, 3 g of aluminum isopropoxide (Al(OCH(CH3)2)3) and 2 g of boric acid (H3BO3) were dissolved together in 10 mL of anhydrous ethanol. Then, acetic acid (CH3COOH) accounting for 3% of the total mass of the solution was added to the mixed solution and the system was stirred gently to make it homogeneous, thus obtaining a boron-aluminum composite solution.

[0069] (4) The boron-aluminum composite solution prepared in step (3) is slowly added dropwise to the zirconium-acetic acid complex solution obtained in step (2) under stirring. After mixing evenly, a clear zirconium-boron-aluminum mixed precursor solution is formed.

[0070] (5) Heat the zirconium-boron-aluminum mixed precursor solution obtained in step (4) to 70°C and keep stirring. Add 12.5 g of methyltrimethoxysilane (CH3Si(OCH3)3) dropwise to it. After the addition is complete, continue the reaction at 65°C for 3 h.

[0071] (6) The reaction solution obtained in step (5) was rotary evaporated at 100°C for 1 h to remove most of the ethanol solvent, and finally a uniform, transparent light green polyzirconium aluminum borosilicate was obtained.

[0072] (7) The polyzirconium aluminum borosiloxane prepared in step (6) is mixed with a cyclohexane solution of methyl silicone resin with a solid content of 60% at a mass ratio of 1:1.5 to obtain the modified silicone resin adhesive.

[0073] Example 3

[0074] The specific process for preparing a modified silicone resin adhesive using polyzirconium aluminum borosiloxane is as follows:

[0075] (1) 10 mL of anhydrous ethanol was placed into the reaction vessel, and after the temperature was raised to 45°C, 6.3 g of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added. The mixture was stirred continuously at 45°C until a clear zirconium alkoxide solution was formed.

[0076] (2) Add 3 g of dibenzoylmethane as a chelating agent to the zirconium alkoxide solution obtained in step (1) and stir continuously for 1.5 h to generate a stable zirconium-dibenzoylmethane complex solution.

[0077] (3) In another reaction vessel, 3 g of aluminum isopropoxide (Al(OCH(CH3)2)3) and 2 g of boric acid (Al(OCH(CH3)2)3) were dissolved together in 10 mL of anhydrous ethanol. Then, 4% of glacial acetic acid was added to the mixed solution and the system was stirred gently to make it homogeneous, thus obtaining a boron-aluminum composite solution.

[0078] (4) The boron-aluminum composite solution prepared in step (3) is slowly added dropwise to the stabilized zirconium-dibenzoylmethane complex solution obtained in step (2) under stirring. After mixing evenly, a clear zirconium-boron-aluminum mixed precursor solution is formed.

[0079] (5) Heat the zirconium-boron-aluminum mixed precursor solution obtained in step (4) to 60°C and keep stirring. Add 15 g of methyltrimethoxysilane (CH3Si(OCH3)3) dropwise to it. After the addition is complete, continue the reaction at 70°C for 3 h.

[0080] (6) The reaction solution obtained in step (5) was rotary evaporated at 100°C for 1 h to remove most of the ethanol solvent, and finally a uniform, transparent light green polyzirconium aluminum borosilicate was obtained.

[0081] (7) The polyzirconium aluminum borosiloxane prepared in step (6) is mixed with a methyl silicone resin cyclohexane solution with a solid content of 60% at a mass ratio of 1:2 to obtain the modified silicone resin adhesive.

[0082] Example 4

[0083] The specific process for preparing a modified silicone resin adhesive using polyzirconium aluminum borosiloxane is as follows:

[0084] 10 mL of anhydrous ethanol was added to the reaction vessel, and the temperature was raised to 50 °C. Then, 6.3 g of zirconium oxychloride octahydrate (ZZrOCl2·8H2O) was added and stirred continuously at 50 °C until a clear zirconium alkoxide solution was formed.

[0085] (2) Add 3 g of citric acid as a chelating agent to the zirconium alkoxide solution obtained in step (1) and stir continuously for 1.5 h to generate a stable zirconium-citric acid complex solution;

[0086] (3) In another reaction vessel, 3 g of aluminum isopropoxide (Al(OCH(CH3)2)3) and 2 g of boric acid (H3BO3) were dissolved together in 10 mL of anhydrous ethanol. Then, 5% of glacial acetic acid (CH3COOH) was added to the mixed solution and the system was stirred gently to make it homogeneous, thus obtaining a boron-aluminum composite solution.

[0087] (4) The boron-aluminum composite solution prepared in step (3) is slowly added dropwise to the stabilized zirconium-citric acid complex solution obtained in step (2) under stirring. After mixing evenly, a clear zirconium-boron-aluminum mixed precursor solution is formed.

[0088] (5) Heat the mixed precursor solution obtained in step (4) to 60°C and keep stirring. Add 7.5g of methyltrimethoxysilane (CH3Si(OCH3)3) dropwise to it. After the addition is complete, continue the reaction at 55°C for 3 h.

[0089] (6) The reaction solution obtained in step (5) was rotary evaporated at 100°C for 1 h to remove most of the ethanol solvent, and finally a uniform, transparent light green polyzirconium aluminum borosilicate was obtained.

[0090] (7) The polyzirconium aluminum borosiloxane prepared in step (6) is mixed with a methyl silicone resin cyclohexane solution with a solid content of 60% at a mass ratio of 1:1 to obtain the modified silicone resin adhesive.

[0091] Example 5

[0092] The specific process for preparing a modified silicone resin adhesive using polyzirconium aluminum borosiloxane is as follows:

[0093] (1) 10 mL of anhydrous ethanol was placed into the reaction vessel, and after the temperature was raised to 50°C, 12.8 g of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added. The mixture was stirred continuously at 50°C until a clear zirconium alkoxide solution was formed.

[0094] (2) Add 3g of ethylenediaminetetraacetic acid as a chelating agent to the zirconium alkoxide solution obtained in step (1) and stir continuously for 2 h to generate a stable zirconium-ethylenediaminetetraacetic acid complex solution.

[0095] (3) In another reaction vessel, 3 g of aluminum isopropoxide (Al(OCH(CH3)2)3) and 2 g of boric acid (H3BO3) were dissolved together in 10 mL of anhydrous ethanol. Then, 2% of glacial acetic acid (CH3COOH) was added to the mixed solution and the system was stirred gently to make it homogeneous, thus obtaining a boron-aluminum composite solution.

[0096] (4) The boron-aluminum composite solution prepared in step (3) is slowly added dropwise to the stabilized zirconium-ethylenediaminetetraacetic acid complex solution obtained in step (2) under stirring. After mixing evenly, a clear zirconium-boron-aluminum mixed precursor solution is formed.

[0097] (5) Heat the mixed precursor solution obtained in step (4) to 60°C and keep stirring. Add 5 g of methyltrimethoxysilane (CH3Si(OCH3)3) dropwise to it. After the addition is complete, continue the reaction at 50°C for 3 h.

[0098] (6) The reaction solution obtained in step (5) was rotary evaporated at 100°C for 1 h to remove most of the ethanol solvent, and finally a uniform, transparent light green polyzirconium aluminum borosilicate was obtained.

[0099] (7) The polyzirconium aluminum borosiloxane prepared in step (6) is mixed with a cyclohexane solution of methyl silicone resin with a solid content of 60% at a mass ratio of 1:1.5 to obtain the modified silicone resin adhesive.

[0100] Comparative Example 1

[0101] The preparation process of cyclohexane solution of methyl silicone resin (MK resin) is as follows:

[0102] (1) Pour the solvent cyclohexane into a beaker;

[0103] (2) Add methyl silicone resin powder, heat up and keep the temperature at 60°C, and stir to fully dissolve the resin powder in the solvent to prepare a cyclohexane solution of methyl silicone resin.

[0104] Comparative Example 2

[0105] The preparation process of a modified silicone resin adhesive is as follows:

[0106] (1) Dissolve 3 g aluminum isopropoxide (Al(OCH(CH3)2)3) and 2 g boric acid (H3BO3) in 10 mL of anhydrous ethanol. Then add 2% glacial acetic acid (CH3COOH) and 2 g distilled water to the mixed solution. Stir gently to make the system homogeneous and obtain a boron-aluminum mixed precursor solution.

[0107] (2) Heat the mixed precursor solution obtained in step (1) to 60°C and keep stirring. Add 4 g of methyltrimethoxysilane (CH3Si(OCH3)3) dropwise to it. After the addition is complete, continue the reaction at 60°C for 3 h.

[0108] (3) The reaction solution obtained in step (2) was rotary evaporated at 100°C for 1 h to remove most of the ethanol solvent, and finally a homogeneous and transparent polyalumina borosilicate was obtained.

[0109] (4) The polyalumina borosilicate prepared in step (3) is mixed with a cyclohexane solution of methyl silicone resin with a solid content of 60% at a mass ratio of 1:2 to obtain the modified silicone resin adhesive.

[0110] Comparative Example 3

[0111] (1) 10 mL of anhydrous ethanol was placed into the reaction vessel, and after the temperature was raised to 40°C, 9.6 g of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added. The mixture was stirred continuously at 40°C until a clear zirconium alkoxide solution was formed.

[0112] (2) Add 3 g of acetylacetone as a chelating agent to the zirconium alkoxide solution obtained in step (1) and stir continuously for 1 h to generate a stable zirconium-acetylacetone complex solution.

[0113] (3) In another reaction vessel, 3 g of aluminum isopropoxide (Al(OCH(CH3)2)3) was dissolved in 10 mL of anhydrous ethanol. Then, 2% of glacial acetic acid (CH3COOH) was added to the mixed solution. The mixture was stirred gently to make it homogeneous, and an aluminum alcohol solution was obtained.

[0114] (4) The aluminum alcohol solution prepared in step (3) is slowly added dropwise to the stabilized zirconium-acetylacetone complex solution obtained in step (2) under stirring. After mixing evenly, a zirconium-aluminum mixed precursor solution is formed.

[0115] (5) Heat the zirconium-aluminum mixed precursor solution obtained in step (4) to 60°C and keep stirring. Add 10 g of methyltrimethoxysilane (CH3Si(OCH3)3) dropwise to it. After the addition is complete, continue the reaction at 60°C for 3 h.

[0116] (6) The reaction solution obtained in step (5) was rotary evaporated at 100°C for 1 h to remove most of the ethanol solvent, and finally a homogeneous and transparent polyzirconium aluminum siloxane was obtained.

[0117] (7) The polyzirconium aluminum siloxane prepared in step (6) is mixed with a methyl silicone resin cyclohexane solution with a solid content of 60% at a mass ratio of 1:2 to obtain the modified silicone resin adhesive.

[0118] Comparative Example 4

[0119] The preparation process of a modified silicone resin adhesive is as follows:

[0120] (1) 10 mL of anhydrous ethanol was placed into the reaction vessel, and after the temperature was raised to 40°C, 9.6 g of zirconium oxychloride octahydrate (ZrOCl2·8H2O) was added. The mixture was stirred continuously at 40°C until a clear zirconium alkoxide solution was formed.

[0121] (2) Add 3 g of acetylacetone as a chelating agent to the zirconium alkoxide solution obtained in step (1) and stir continuously for 1 h to generate a stable zirconium-acetylacetone complex solution.

[0122] (3) In another reaction vessel, 2 g of boric acid (H3BO3) was dissolved in 10 mL of anhydrous ethanol, and then 2% of glacial acetic acid (CH3COOH) was added to the mixed solution. The mixture was stirred gently to make it homogeneous, and a boron alcohol solution was obtained.

[0123] (4) The boron alcohol solution prepared in step (3) is slowly added dropwise to the stabilized zirconium-acetylacetone complex solution obtained in step (2) under stirring. After mixing evenly, a zirconium-boron mixed precursor solution is formed.

[0124] (5) Heat the mixed precursor solution obtained in step (4) to 60°C and keep stirring. Add 10 g of methyltrimethoxysilane (CH3Si(OCH3)3) dropwise to it. After the addition is complete, continue the reaction at 60°C for 3 h.

[0125] (6) The reaction solution obtained in step (5) was rotary evaporated at 100°C for 1 h to remove most of the ethanol solvent, and finally a homogeneous and transparent polyzirconium borosiloxane was obtained.

[0126] (7) The polyzirconium borosiloxane prepared in step (6) is mixed with a cyclohexane solution of methyl silicone resin with a solid content of 60% at a mass ratio of 1:2 to obtain the modified silicone resin adhesive.

[0127] Effect verification:

[0128] Adhesion performance test:

[0129] (1) Zirconia ceramics were bonded using the modified silicone resins prepared in Examples 1-5 and Comparative Examples 1-4 respectively. The curing regime was 25℃ / 96h→150℃ / 2h, and finally, zirconia ceramic bonding test pieces bonded with different silicone resins were obtained.

[0130] (2) Under an oxygen atmosphere, the cured zirconia ceramic bonding test pieces were subjected to heat treatment at 200℃, 500℃, 800℃, 1000℃ and 1200℃ in a box furnace for 1 hour.

[0131] (3) The above-mentioned zirconia ceramic bonding test specimens that have been heat-treated at different temperatures were tested according to the test method of GB / T 7124-2008. The high-temperature bonding performance of the modified silicone resins prepared by different methods was analyzed. The results are shown in Table 1.

[0132] Table 1 High-temperature bonding performance

[0133] Room temperature shear strength (MPa) Shear strength at 200℃ (MPa) Shear strength at 500℃ (MPa) Shear strength at 800℃ (MPa) Shear strength at 1000℃ (MPa) Shear strength at 1200℃ (MPa) Example 1 2.41 3.12 2.35 2.22 2.56 2.75 Example 2 2.15 2.85 1.98 1.88 2.01 2.15 Example 3 2.13 2.95 1.96 1.81 2.12 2.17 Example 4 2.06 2.84 1.87 1.79 2.07 2.24 Example 5 2.01 2.75 1.86 1.84 1.98 2.03 Comparative Example 1 2.23 2.57 0.11 0 0 0 Comparative Example 2 2.17 2.61 0.32 0.21 0.24 0 Comparative Example 3 2.11 2.71 0.55 0 0 0 Comparative Example 4 2.05 2.75 0.46 0.22 0 0

[0134] As shown in Table 1, the polyzirconium aluminum borosiloxane modified silicone resin adhesives prepared in Examples 1-5 of this invention exhibit excellent high-temperature bonding performance in the range from room temperature to 1200℃. In particular, they maintain a shear strength of over 2.0 MPa above 1000-1200℃. Example 1, for instance, achieves a shear strength of 2.75 MPa at 1200℃, significantly better than the comparative examples. In contrast, Comparative Example 1 (pure methyl silicone resin) completely loses its bonding ability at temperatures of 500℃ and above; Comparative Examples 2 (containing only Al and B), 3 (containing only Zr and Al), and 4 (containing only Zr and B) exhibit some strength at low temperatures, but essentially fail or show extremely low shear strength at 800℃ and above. This demonstrates that only polyzirconium aluminum borosiloxanes constructed by simultaneously introducing zirconium, aluminum, and boron can synergistically endow silicone resin adhesives with excellent high-temperature structural stability and durable bonding performance.

[0135] Figure 1 A comparison of the infrared spectra of the modified silicone resin binder (Example 1) and methyl silicone resin (Comparative Example 1) is shown. Compared with the unmodified methyl silicone resin, the modified silicone resin binder exhibits a significant change in characteristic peaks in its infrared spectrum. At approximately 1100 cm⁻¹... -1 Strong stretching vibration peaks of Si-O-Si bonds were observed at both sites, indicating that both possess a complete silicon-oxygen network structure. However, the modified silicone adhesive showed a peak at approximately 960 cm⁻¹. -1 The newly appearing characteristic absorption peaks are attributed to the Si-O-Zr bonds, and at approximately 920 cm⁻¹ -1 and 870 cm -1Vibrational peaks corresponding to Si-O-Al and Si-OB bonds appeared nearby. The appearance of these characteristic peaks directly proves that zirconium, aluminum, and boron elements have been introduced into the siloxane framework through chemical bonding, forming a stable hybrid structure. Furthermore, no superposition of characteristic peaks due to physical mixing was found in the spectrum, indicating that the modification process is a chemical bonding mechanism. This result confirms the successful synthesis of polyzirconium aluminum borosilicate and provides a structural basis for improving the performance of modified silicone resin adhesives.

[0136] Figure 2 XPS data for the modified silicone resin adhesive prepared in Example 1. The chemical state of the surface elements of the cured modified silicone resin adhesive (Example 1) was measured using X-ray photoelectron spectroscopy. Oxygen, carbon, zirconium, boron, aluminum, and silicon were detected in the full-scan XPS spectrum, which is consistent with the infrared results, confirming the formation of Si-OM (M = Zr, Al, B) bonds in the modified silicone resin adhesive prepared in Example 1.

[0137] Figure 3 The X-ray diffraction (XRD) patterns of the modified silicone resin adhesive from Example 1 during heat treatment from 200°C to 1200°C show an evolution. As can be seen from the figures, with increasing temperature, the material exhibits a clear, phase-dependent phase transition, forming a progressively evolving bonding mechanism. Specifically:

[0138] At 200℃, the diffraction pattern only showed broadened diffuse peaks, corresponding to the amorphous structure of the silicone resin, indicating that the material still retained its organic characteristics. When the temperature rose to 500℃, obvious glassy diffuse peaks appeared in the diffraction pattern, marking the beginning of glass phase formation. At this point, the organic components decomposed and initially constructed a silicon-zirconium-aluminum-boron inorganic network, realizing the transition from organic to inorganic adhesive structure. As the temperature continued to rise to 800℃, crystalline diffraction peaks belonging to the zirconia (ZrO2) ceramic phase began to appear in the pattern, while the glass phase characteristics remained, indicating that the material entered a composite state of glass and ceramic phases, further enhancing the adhesive system. When the temperature continued to rise to 1000℃, characteristic diffraction peaks of the mullite phase (3Al2O3·2SiO2) appeared, forming a three-phase composite system together with the continuously enhanced zirconia diffraction peaks and the still discernible glass phase, significantly improving the high-temperature adhesive stability. When the temperature reaches 1200℃, the diffuse peaks of the glass phase completely disappear, replaced by distinct diffraction peaks of the silica (SiO2) ceramic phase, while the diffraction peaks of the zirconia and mullite phases remain stable. At this point, the material is completely transformed into a silica-zirconia-mullite multiphase ceramic system, achieving a structural transformation from an amorphous state to a fully crystalline ceramic. This series of transformations indicates that the modified silicone resin binder, through a gradual evolution from organic matter → glass phase → glass / ceramic composite phase → all-ceramic phase, forms a hierarchical bonding mechanism with temperature-responsive characteristics. This process enables it to maintain effective bonding performance over a wide temperature range from 200℃ to 1200℃, ultimately achieving excellent high-temperature bonding reliability through the stable multiphase ceramic structure formed at high temperatures.

[0139] Figure 4 In Figure a, the TG-DSC curve of the modified silicone resin binder (Example 1) under an oxygen atmosphere is shown, and in Figure b, the TG-DSC curve of the methyl silicone resin (Comparative Example 1) under an oxygen atmosphere is shown. As can be seen from the figure, the pyrolysis start temperature of the modified silicone resin binder prepared in Example 1 of the present invention is 472°C, the pyrolysis end temperature is 693°C, and the thermogravimetric residual mass fraction is 84.2%. In contrast, the pyrolysis start temperature of the unmodified methyl silicone resin (Comparative Example 1) is only 409°C, the pyrolysis end temperature is only 566°C, and the thermogravimetric residual mass fraction is 82.3%. This indicates that the modified silicone resin binder of the present invention can improve the thermal oxidation resistance of silicone resin.

[0140] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a hyperbranched polymer polyzirconium aluminum borosilicate, characterized in that, Includes the following steps: (1) Dissolve the zirconium source and chelating agent in an organic solvent and stir to obtain a zirconium-chelating agent complex solution; (2) Dissolve aluminum isopropoxide and boric acid in an organic solvent, add glacial acetic acid, and stir until homogeneous to obtain a boron-aluminum composite solution; (3) The zirconium-chelating agent complex solution and the boron-aluminum composite solution are mixed evenly to obtain a zirconium-boron-aluminum mixed precursor solution. Then, methyltrimethoxysilane is added to it, and the reaction is carried out. The organic solvent is then removed by rotary evaporation to obtain a uniform and transparent polyzirconium aluminum borosiloxane. The zirconium source is zirconium oxychloride octahydrate; The organic solvent is anhydrous ethanol; The chelating agent is selected from acetylacetone, acetic acid, dibenzoylmethane, citric acid, or ethylenediaminetetraacetic acid; The mass ratio of the zirconium source, aluminum isopropoxide, boric acid and methyltrimethoxysilane is (6.3-12.8):3:2:(5-15).

2. The method for preparing a hyperbranched polymer polyzirconium aluminum borosilicate according to claim 1, characterized in that, The mass ratio of the zirconium source to the chelating agent is (6.3-12.8):

3.

3. The method for preparing a hyperbranched polymer polyzirconium aluminum borosilicate according to claim 1, characterized in that, In step (1), the stirring temperature is 40-50℃.

4. The method for preparing a hyperbranched polymer polyzirconium aluminum borosilicate according to claim 1, characterized in that, The amount of glacial acetic acid added is 2-5 wt.% of the boron-aluminum composite solution.

5. The method for preparing a hyperbranched polymer polyzirconium aluminum borosilicate according to claim 1, characterized in that, In step (3), the reaction conditions are: reacting at 50-70℃ for 3 h; The conditions for rotary evaporation are: rotary evaporation at 100°C for 1 hour.

6. A hyperbranched polymer polyzirconium aluminum borosilicate, characterized in that, It is prepared by the preparation method according to any one of claims 1-5.

7. The application of the hyperbranched polymer polyzirconium aluminum borosilicate as described in claim 6 in the preparation of high-temperature resistant modified silicone resin adhesives.

8. The application of the hyperbranched polymer polyzirconium aluminum borosilicate according to claim 7 in the preparation of high-temperature resistant modified silicone resin adhesive, characterized in that, The preparation process of the modified silicone resin adhesive is as follows: The modified silicone resin adhesive was prepared by mixing the polyzirconium aluminum borosiloxane with a cyclohexane solution containing methyl silicone resin at a mass ratio of 1:1-2. The mass concentration of the cyclohexane solution containing methyl silicone resin is 60%.

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