Binding material, preparation method thereof and application of binding material in silica gel glass

Abstract

The invention belongs to the technical field of adhesives, and particularly relates to an adhesive material, a preparation method thereof and application of the adhesive material in silica gel glass. The preparation method of the binding material comprises the following steps: (1) reacting a diamino siloxane monomer, an amido-containing diamine monomer, other diamine monomers and a dianhydride monomer by adopting a step-by-step polymerization process to prepare polyamide acid; (2) carrying out chemical imidization reaction on the polyamide acid, and precipitating to obtain polyimide powder; and (3) mixing the polyimide powder, epoxy resin and a curing agent to obtain the binding material. According to the invention, diamine monomers such as a diamino siloxane monomer and an amido-containing diamine monomer are adopted as raw materials, polyimide is prepared through a step-by-step polymerization process, and introduction of a siloxane chain segment and an amido bond not only improves the solubility of polyimide, but also improves the compatibility and interface energy of polyimide and epoxy resin; and the bonding strength of the bonding material is improved.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to an adhesive material, its preparation method, and its application in silicone glass. Background Technology

[0002] With the development of the synthetic polymer materials industry and the improvement of industrial levels, adhesives have received increasing attention and have gradually developed into an independent industrial sector—the adhesive industry. The technology of joining various objects using adhesives is called bonding technology. In recent years, adhesives have been widely used in various industries, and bonding technology has matured, becoming one of the three major joining technologies along with adhesive bonding, welding, and mechanical joining.

[0003] Epoxy resin refers to compounds containing two or more epoxy groups in one molecule, which can form a three-dimensional cross-linked network cured product under appropriate processing conditions and in the presence of a curing agent. Epoxy resin is the most widely used matrix resin in polymer-based composite materials. As a thermosetting resin, epoxy resin possesses excellent adhesive properties, abrasion resistance, mechanical properties, chemical stability, electrical insulation, as well as advantages such as low shrinkage, ease of processing and molding, good stress transfer, and low cost. It is widely used in coatings, adhesives, light industry, construction, machinery, aerospace, and other fields. In recent years, its applications have expanded to semiconductor packaging materials, fiber-reinforced materials, laminates, copper foil, integrated circuits, and other areas.

[0004] However, due to its three-dimensional structure, lack of inter-chain sliding, low C / C and CH bond energies, high surface energy, and the presence of hydroxyl groups, epoxy resin exhibits drawbacks such as high internal stress, brittleness, easy degradation at high temperatures, and susceptibility to water. Furthermore, unmodified epoxy resin cured products are generally brittle, exhibiting poor resistance to peeling, cracking, and impact, and weak adhesion to polar materials. Therefore, to meet higher requirements, researchers have devised various methods to modify epoxy resin adhesives to improve their toughness, thermal stability, electrical properties, and solvent resistance.

[0005] Epoxy resin adhesives are a class of engineering adhesives formulated from epoxy resin base materials, curing agents, diluents, accelerators, and fillers. Due to their good adhesion, functionality, relatively low price, and simple bonding process, they are widely used in home appliances, water conservancy and transportation, electronics, and aerospace industries. In recent years, with the development of production and daily life, various glass, ceramic, or metal materials have been widely used, especially in the consumer sector, where the demand for various special functional materials is increasing. For example, the technology (CN119552503A) jointly developed by Zibo Qianbaiyuan Home Furnishings Co., Ltd. and Shandong University of Technology discloses a nano-photocatalytic self-cleaning composite material. The self-cleaning antibacterial composite material prepared from this material has good formability and a broad-spectrum and highly efficient antibacterial effect, better meeting the requirements of food, pharmaceuticals, fruits, and vegetables for packaging materials. Using this composite material to prepare a food preservation cap can produce a strong antibacterial effect and provide long-term antibacterial activity. However, research on bonding materials between glass, ceramic, or metal materials and protective sleeves in production and daily life is relatively limited. Existing adhesive materials are prone to defects at the bonding interface, which reduces the bonding strength. Summary of the Invention

[0006] To address the technical problems of low bonding strength and poor temperature resistance in existing adhesive materials, this invention provides an adhesive material and its preparation method. This method is simple, and the prepared adhesive material has low industrialization cost, meeting the current requirements of high efficiency, economy, and environmental protection.

[0007] Based on the above objectives, this invention provides a method for preparing an adhesive material, comprising the following steps: A method for preparing an adhesive material includes the following steps: (1) Dissolve diaminosiloxane monomer I, amide-containing diamine monomer, and other diamine monomers in an organic solvent, then add dianhydride monomer, react for 1-2 h, then add diaminosiloxane monomer II to continue the reaction to obtain a polyamic acid solution; the molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomers is (0.5-1):(2-4):(2-4):10; (2) Add a chemical imidizing agent to the polyamic acid solution to carry out an imidization reaction, then pour it into the precipitation solution to precipitate, and obtain polyimide powder after filtration, washing and drying; (3) Disperse polyimide powder and epoxy resin in an organic solvent and stir evenly. Then remove the solvent, add curing agent, and stir evenly to obtain adhesive material.

[0008] Polyimide is a rigid-chain polymer with a highly regular chemical structure containing imide rings in its main chain. Polyimide possesses excellent heat resistance, being one of the most thermally stable polymers to date, maintaining excellent mechanical and electrical insulation properties even at low temperatures. Furthermore, it exhibits excellent oil and organic solvent resistance, making it widely applicable in adhesives. It is commonly used as a high-temperature structural adhesive for bonding metals, non-metals, and polymers. Modifying epoxy resin with polyimide can combine the advantages of both, resulting in high-temperature adhesives with good mechanical properties and bond strength. In polyimide / epoxy resin blends, the key lies in the proper mixing of the two components. Because polyimide has a high flow temperature, mixing it with epoxy resin under normal operating conditions is challenging.

[0009] To address the aforementioned issues, this invention utilizes diamine monomers such as diaminosiloxane monomers and amide-containing diamine monomers as raw materials, and prepares a polyimide with good solvent solubility through a special process. This polyimide can be blended with epoxy resin in the molecular state, greatly improving the bonding strength and temperature resistance of the epoxy resin.

[0010] Among them, the siloxane segments in the diaminosiloxane monomer molecule possess excellent flexibility and rotational freedom. As the flexible part of the polyimide backbone, it effectively "toughens" the final polyimide, transforming it from a rigid and brittle material into one with a certain degree of flexibility. Meanwhile, the amide-containing diamine monomer is a diamine containing amide bonds. These amide bonds can form strong intermolecular hydrogen bonds, endowing the material with extremely high mechanical strength and modulus. More importantly, the introduction of siloxane segments and amide bonds not only improves the solubility of polyimide but also enhances its compatibility with epoxy resin, further increasing the interfacial energy between polyimide and epoxy resin, and improving the bonding strength of the adhesive material.

[0011] In the formed adhesive material, the introduction of flexible siloxane segments and rigid amide segments effectively induces crazes, absorbs and disperses impact energy, and hinders crack propagation, thereby significantly reducing the brittleness of epoxy resin and improving the strength of the adhesive layer. The residual amino or anhydride groups in the polyimide can also act as curing agents or compatibilizers when blended with epoxy resin, participating in the curing and crosslinking reaction of the epoxy resin, improving the interfacial bonding between the two phases, and preventing phase separation. During the curing process, the molecular chains of polyimide and the network of epoxy resin become entangled, even forming a partially interpenetrating polymer network, greatly enhancing the compatibility and integrity of the two phases.

[0012] In one embodiment, the diaminosiloxane monomer I and diaminosiloxane monomer II can be the same or different, specifically selected from one or more of 1,3-bis(3-aminopropyl)tetramethyldisiloxane (i.e., 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane), 1,3-bis(4-aminobutyl)tetramethyldisiloxane, bis(4-aminophenyl)tetramethylsiloxane, and bis(γ-aminopropyl)tetraphenyldisiloxane. As a diamine monomer containing siloxane, it has high reactivity. This invention employs a staged feeding method to promote the uniform dispersion of the diamine monomer containing siloxane in the polyimide molecular chain. The initial addition of a small amount of diaminosiloxane monomer I can promote the formation of oligomers. After a period of reaction, a large amount of diaminosiloxane monomer II is added to promote the growth of the molecular chain. Adding a large amount of diaminosiloxane monomer initially will affect the increase in the molecular weight of the polyimide, leading to a decrease in the mechanical properties of the polymer.

[0013] In one embodiment, the amide-containing diamine monomer is selected from one or more of 4,4-diaminobenzoylaniline, 3,4-diaminobenzoylaniline, 2-methyl-4,4-diaminobenzoylaniline, and 3-methyl-4,4-diaminobenzoylaniline. Although the amide-containing diamine can form strong intermolecular hydrogen bonds with epoxy resin, due to the high rigidity of this monomer, its dosage should not be excessive, otherwise it will lead to a decrease in the adhesive properties of the epoxy resin.

[0014] In one embodiment, the other diamine monomer (i.e., a diamine monomer that does not contain siloxane and amide groups) is selected from p-phenylenediamine, m-phenylenediamine, 2-trifluoromethyl-1,4-diaminobenzene, 5-methyl-1,3-diaminobenzene, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-bis(trifluoromethyl)diphenylmethane, 3,3'-diaminobenzophenone, and 4,4'-diaminodiphenylmethane. One or more of methyl ketone, 4,4'-diaminodiphenyl sulfone, 4,4'-bis(4-aminophenoxy)benzene, 4,4'-bis(3-aminophenoxy)benzene, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-bis(trifluoromethyl)biphenyl, or 4,4'-bis(4-aminophenoxy)biphenyl. Further, one or more of 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl can be selected. Specifically, fluorinated dianhydrides such as 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl can be selected.

[0015] In one embodiment, the organic solvent in step (1) is selected from one or more of N,N-dimethylacetamide, N,N-dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, acetone, acetonitrile, and dimethyl sulfoxide. Further, solvents with strong polarity, such as N,N-dimethylacetamide, N,N-dimethylformamide, tetrahydrofuran, and N-methylpyrrolidone, can be selected.

[0016] In one embodiment, the dianhydride monomer is selected from one or more of the following: pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phenyl dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)phenyl dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, and 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride. Furthermore, a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride can be selected. By selecting ketone-containing and fluorine-containing dianhydrides, both reinforcing and toughening effects can be achieved, thereby improving the bonding strength and thermal stability of the adhesive material.

[0017] In one embodiment, the molar ratio of diamine monomer to dianhydride monomer is (1.01-1.05):1. An excess of diamine monomer can impart active amino groups to the polyimide, enabling it to participate in the curing reaction of the epoxy resin and improving the compatibility between the polyimide and the epoxy resin.

[0018] In one embodiment, the reaction temperature in step (1) is 20-35°C, and the reaction time is 5-8 hours.

[0019] In one embodiment, the chemical imidizing agent is a mixture of acetic anhydride and pyridine. Specifically, the molar ratio of acetic anhydride to pyridine is (1-5):1, and the mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is (1-5):1; particularly, the mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is (2-3):1.

[0020] In one embodiment, the imidization reaction time is 5-7 hours.

[0021] In one embodiment, the precipitate is one or more of deionized water, methanol, ethanol, isopropanol, propanol, butanol, or isobutanol.

[0022] In one embodiment, the mass ratio of the polyimide powder to the epoxy resin is (0.1-0.3):1.

[0023] In one embodiment, the organic solvent in step (3) is one or more of N,N-dimethylacetamide, N,N-dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, acetone, acetonitrile, and dimethyl sulfoxide. By adding an active diluent, the polyimide is fully dissolved, promoting the dispersion of the polyimide in the epoxy resin and improving the compatibility between the two.

[0024] In one embodiment, the curing agent is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, polyamide, trimethylhexamethylenediamine, polyether diamine, and m-phenylenediamine. The mass ratio of the curing agent to the epoxy resin is 1:(5-10). Removing excess solvent before adding the curing agent can eliminate the influence of excess solvent and prevent the formation of bubbles. Generally speaking, aliphatic curing agents have a faster curing speed and lower cost; while epoxy resins made with aromatic curing agents have higher heat resistance.

[0025] In one embodiment, the adhesive material obtained by uniform stirring can be cured at 20-120°C for 10-30 hours; in particular, it can be cured at room temperature.

[0026] On the other hand, the present invention also provides an adhesive material and its application in the field of silicone glass. The adhesive material prepared by the present invention has excellent mechanical strength and heat resistance, and exhibits high bonding strength to matrices such as metals, ceramics, glass, and plastics. In particular, it can be used as an adhesive material for silicone glass.

[0027] Beneficial effects: This invention uses diamine monomers such as diaminosiloxane monomers and amide-containing diamine monomers as raw materials to prepare a polyimide with good solvent solubility through a special process. This polyimide can be blended with epoxy resin in the molecular state, significantly improving the bonding strength and temperature resistance of the epoxy resin. The introduction of flexible siloxane segments and rigid amide segments effectively induces crazes, absorbs and disperses impact energy, and hinders crack propagation, thereby significantly reducing the brittleness of the epoxy resin and improving the strength of the adhesive layer. The residual amino or anhydride groups in the polyimide can also act as curing agents or compatibilizers when blended with epoxy resin, participating in the curing and crosslinking reaction of the epoxy resin, improving the interfacial bonding force between the two phases, and preventing phase separation. During the curing process, the molecular chains of the polyimide and the network of the epoxy resin intertwine, even forming a partially interpenetrating polymer network, greatly enhancing the compatibility and integrity of the two phases. Detailed Implementation

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0031] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0032] Unless otherwise specified, the preparation processes and raw materials of the following examples and comparative examples are the same.

[0033] Performance testing: The heat resistance and tensile shear properties of the adhesive material were tested. Specifically, under the same test conditions, the adhesive material was uniformly coated on the surface of an aluminum alloy substrate and cured for 24 hours; its 5% thermal decomposition temperature and shear strength were tested using thermogravimetric analysis (TG) and GB7124-86, respectively.

[0034] Example 1 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoyl aniline, and other diamine monomer 4,4'-diaminodiphenyl ether were dissolved in the organic solvent N,N-dimethylacetamide. Then, dianhydride monomer was added, and the reaction was carried out at 25°C for 1 h. Diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was added and the reaction was continued for 5 h to obtain a polyamic acid solution. The molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomer was 0.5:2:2:10. The dianhydride monomer was selected from 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride. The molar ratio of diamine monomer to dianhydride monomer was 1.03:1. (2) Add a chemical imidizing agent to the polyamic acid solution and react for 5 hours. Then pour it into deionized water to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 2:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.15:1; the mass ratio of curing agent to epoxy resin is 1:7. The 5% thermal decomposition temperature and shear strength were tested to be 364℃ and 24.4MPa, respectively.

[0035] Example 2 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoyl aniline, and other diamine monomer 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were dissolved in the organic solvent N-methylpyrrolidone. Then, dianhydride monomer was added, and the reaction was carried out at 25°C for 2 h. Diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was added and the reaction was continued for 8 h to obtain a polyamic acid solution. The molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomer was 1:4:4:10. The dianhydride monomer was selected from pyromellitic dianhydride. The molar ratio of diamine monomer to dianhydride monomer was 1.03:1. (2) Add a chemical imidizing agent to the polyamic acid solution and react for 7 hours. Then pour it into methanol to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 3.5:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.22:1; the mass ratio of curing agent to epoxy resin is 1:8. The 5% thermal decomposition temperature and shear strength are tested to be 380℃ and 22.3MPa, respectively.

[0036] Example 3 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoyl aniline, and other diamine monomer 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were dissolved in the organic solvent N,N-dimethylacetamide. Then, dianhydride monomer was added, and the reaction was carried out at 25°C for 1.6 h. Diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was added and the reaction was continued for 6 h to obtain a polyamic acid solution. The molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomer was 0.8:3:3:10. The dianhydride monomer was selected from 3,3',4,4'-benzophenone tetracarboxylic dianhydride. The molar ratio of diamine monomer to dianhydride monomer was 1.03:1. (2) Add a chemical imidizing agent to the polyamic acid solution and react for 6 hours. Then pour it into ethanol to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 3:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.18:1; the mass ratio of curing agent to epoxy resin is 1:8. The 5% thermal decomposition temperature and shear strength are tested to be 371℃ and 22.8MPa, respectively.

[0037] Example 4 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoyl aniline, and other diamine monomer 4,4'-diaminobenzophenone were dissolved in the organic solvent N-methylpyrrolidone. Then, dianhydride monomers were added, and the reaction was carried out at 25°C for 1.2 h. Diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was added and the reaction was continued for 7.5 h to obtain a polyamic acid solution. The molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomers was 0.6:3.5:2.5:10. The dianhydride monomer was selected from a mixture of pyromellitic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride with a molar ratio of 1:1. The molar ratio of diamine monomer to dianhydride monomer was 1.03:1. (2) Add a chemical imidizing agent to the polyamic acid solution and react for 5 hours. Then pour it into methanol to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 2.5:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.17:1; the mass ratio of curing agent to epoxy resin is 1:9. The 5% thermal decomposition temperature and shear strength are tested to be 370℃ and 23.6MPa, respectively.

[0038] Example 5 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoylaniline, and other diamine monomer 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were dissolved in the organic solvent N,N-dimethylacetamide. Then, dianhydride monomer was added, and the reaction was carried out at 25°C for 1.6 h. Diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was added and the reaction was continued for 6 h to obtain a polyamic acid solution. The molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomer was 0.8:3:3:10. The dianhydride monomer was selected from 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride. The molar ratio of diamine monomer to dianhydride monomer was 1.03:1. (2) Add a chemical imidizing agent to the polyamic acid solution and react for 6 hours. Then pour it into ethanol to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 3:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.18:1; the mass ratio of curing agent to epoxy resin is 1:8. The 5% thermal decomposition temperature and shear strength were tested to be 367℃ and 23.1MPa, respectively.

[0039] Example 6 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoyl aniline, and other diamine monomer 4,4'-diaminodiphenyl sulfone were dissolved in the organic solvent N,N-dimethylacetamide. Then, dianhydride monomers were added, and the reaction was carried out at 25°C for 1.3 h. Diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was then added and the reaction was continued. The reaction was carried out for 6 hours to obtain a polyamic acid solution; the molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomers was 0.7:2.5:2.5:10; the dianhydride monomer was selected from a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1:2; the molar ratio of diamine monomer to dianhydride monomer was 1.03:1; (2) Add a chemical imidizing agent to the polyamic acid solution and react for 5.6 h. Then pour it into deionized water to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 2.8:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.16:1; the mass ratio of curing agent to epoxy resin is 1:7. The 5% thermal decomposition temperature and shear strength were tested to be 368℃ and 23.9MPa, respectively.

[0040] Example 7 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoylaniline, and other diamine monomer 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were dissolved in the organic solvent N,N-dimethylacetamide. Then, dianhydride monomer was added, and the reaction was carried out at 25°C for 1.8 h. Diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was added and the reaction was continued for 7 h to obtain a polyamic acid solution. The molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomer was 0.9:3.5:3.5:10. The dianhydride monomer was selected from 3,3',4,4'-biphenyltetracarboxylic dianhydride. The molar ratio of diamine monomer to dianhydride monomer was 1.03:1. (2) Add a chemical imidizing agent to the polyamic acid solution and react for 6.5 h. Then pour it into ethanol to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 3.2:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.2:1; the mass ratio of curing agent to epoxy resin is 1:8.5. The 5% thermal decomposition temperature and shear strength were tested to be 375℃ and 22.6MPa, respectively.

[0041] Example 8 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoyl aniline, and other diamine monomers 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were dissolved in the organic solvent N,N-dimethylacetamide. Then, dianhydride monomers were added, and the reaction was carried out at 25°C for 1.6 h. Then, diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was added. The reaction of diaminosiloxane (diaminosiloxane) continued for 6 hours to obtain a polyamic acid solution; the molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomers was 0.8:3:3:10; the dianhydride monomer was selected from a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 2:1; the molar ratio of diamine monomer to dianhydride monomer was 1.03:1; (2) Add a chemical imidizing agent to the polyamic acid solution and react for 6 hours. Then pour it into ethanol to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 3:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.18:1; the mass ratio of curing agent to epoxy resin is 1:8. The 5% thermal decomposition temperature and shear strength were tested to be 383℃ and 24.6MPa, respectively.

[0042] Comparative Example 1 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoyl aniline, and other diamine monomers 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were dissolved in the organic solvent N,N-dimethylacetamide. Then, dianhydride monomers were added, and the reaction was carried out at 25°C for 1.6 h. Then, diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was added. The reaction of diaminosiloxane (diaminosiloxane) continued for 6 hours to obtain a polyamic acid solution; the molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomers was 3:0.8:3:10; the dianhydride monomer was selected from a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 2:1; the molar ratio of diamine monomer to dianhydride monomer was 1.03:1; (2) Add a chemical imidizing agent to the polyamic acid solution and react for 6 hours. Then pour it into ethanol to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 3:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.18:1; the mass ratio of curing agent to epoxy resin is 1:8. The 5% thermal decomposition temperature and shear strength were tested to be 342℃ and 18.5MPa, respectively.

[0043] Comparative Example 2 A method for preparing an adhesive material includes the following steps: (1) Diaminosiloxane monomer I (1,3-bis(3-aminopropyl)tetramethyldisiloxane), amide-containing diamine monomer 4,4-diaminobenzoyl aniline, and other diamine monomers 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl were dissolved in the organic solvent N,N-dimethylacetamide. Then, dianhydride monomers were added, and the reaction was carried out at 25°C for 1.6 h. Then, diaminosiloxane monomer II (1,3-bis(3-aminopropyl)tetramethyldisiloxane) was added. The reaction of diaminosiloxane (diaminosiloxane) continued for 6 hours to obtain a polyamic acid solution; the molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomers was 0.8:3:7:10; the dianhydride monomer was selected from a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid) hexafluoropropane dianhydride in a molar ratio of 2:1; the molar ratio of diamine monomer to dianhydride monomer was 1.03:1; (2) Add a chemical imidizing agent to the polyamic acid solution and react for 6 hours. Then pour it into ethanol to precipitate. After filtration, washing and drying, polyimide powder is obtained. The chemical imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2.5:1. The mass ratio of the mixture to the sum of the masses of the dianhydride monomer and the diamine monomer is 3:1. (3) Disperse polyimide powder and epoxy resin E51 in tetrahydrofuran and stir evenly. Then remove the solvent under vacuum, add triethylenetetramine curing agent, and stir evenly to obtain the adhesive material. The mass ratio of polyimide powder to epoxy resin is 0.18:1; the mass ratio of curing agent to epoxy resin is 1:8. The 5% thermal decomposition temperature and shear strength are tested to be 365℃ and 17.3MPa, respectively.

[0044] As can be seen from the above examples and comparative examples, this invention uses diamine monomers such as diaminosiloxane monomers and amide-containing diamine monomers as raw materials, and prepares a polyimide with good solubility through a stepwise polymerization process. This polyimide can be blended with epoxy resin in the molecular state, greatly improving the bonding strength and temperature resistance of the epoxy resin. The siloxane segments in the diaminosiloxane monomer molecule have excellent flexibility and rotational freedom. As the flexible part of the polyimide backbone, it effectively "toughens" the final polyimide, transforming it from a rigid and brittle material into a material with a certain degree of flexibility. The amide-containing diamine monomer is a diamine containing amide bonds. These amide bonds can form strong intermolecular hydrogen bonds, giving the material extremely high mechanical strength and modulus. More importantly, the introduction of siloxane segments and amide bonds not only improves the solubility of the polyimide but also improves the compatibility between the polyimide and epoxy resin, further increasing the interfacial energy between the polyimide and epoxy resin and improving the bonding strength of the adhesive material.

[0045] Specifically, compared to Example 8, Comparative Example 1 used an excessive amount of diaminosiloxane monomer initially. Because diaminosiloxane monomers are highly reactive, adding a large amount initially leads to the formation of a large amount of polyamic acid oligomers, which is detrimental to the growth of polymer molecular weight and results in a decrease in the mechanical strength and heat resistance of the adhesive material. In Comparative Example 2, compared to Example 8, the amount of amide-containing diamine monomer was excessive. Although amide-containing diamine monomers can form strong intermolecular hydrogen bonds between epoxy resins, their high rigidity means that excessive use leads to a decrease in the adhesive performance of the epoxy resin.

[0046] The above examples and comparative examples demonstrate that the introduction of flexible siloxane segments and rigid amide segments into the formed adhesive material can effectively improve the strength of the adhesive layer. The residual amino or anhydride groups in the polyimide can also act as curing agents or compatibilizers when blended with epoxy resin, participating in the curing and crosslinking reaction of the epoxy resin, improving the interfacial bonding force between the two phases, and preventing phase separation. During the curing process, the molecular chains of polyimide and the network of epoxy resin become entangled, even forming a partially interpenetrating polymer network, greatly enhancing the compatibility and integrity of the two phases.

[0047] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing an adhesive material, characterized in that, Includes the following steps: (1) Dissolve diaminosiloxane monomer I, amide-containing diamine monomer, and other diamine monomers in an organic solvent, then add dianhydride monomer, react for 1-2 h, then add diaminosiloxane monomer II to continue the reaction to obtain a polyamic acid solution; the molar ratio of diaminosiloxane monomer I, diaminosiloxane monomer II, amide-containing diamine monomer, and other diamine monomers is (0.5-1):(2-4):(2-4):10; (2) Add a chemical imidizing agent to the polyamic acid solution to carry out an imidization reaction, then pour it into the precipitation solution to precipitate, and obtain polyimide powder after filtration, washing and drying; (3) Disperse polyimide powder and epoxy resin in an organic solvent and stir evenly. Then remove the solvent, add curing agent, and stir evenly to obtain adhesive material.

2. The method for preparing an adhesive material as described in claim 1, characterized in that, In step (1), diaminosiloxane monomer I and diaminosiloxane monomer II are independently selected from one or more of 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 1,3-bis(4-aminobutyl)tetramethyldisiloxane, bis(4-aminophenyl)tetramethylsiloxane, and bis(γ-aminopropyl)tetraphenyldisiloxane.

3. The method for preparing an adhesive material as described in claim 1, characterized in that, In step (1), the amide-containing diamine monomer is selected from one or more of 4,4-diaminobenzoyl aniline, 3,4-diaminobenzoyl aniline, 2-methyl-4,4-diaminobenzoyl aniline, and 3-methyl-4,4-diaminobenzoyl aniline.

4. The method for preparing an adhesive material as described in claim 1, characterized in that, In step (1), the other diamine monomers are selected from p-phenylenediamine, m-phenylenediamine, 2-trifluoromethyl-1,4-diaminobenzene, 5-methyl-1,3-diaminobenzene, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-bis(trifluoromethyl)diphenylmethane, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenylmethane. One or more of the following: 4,4'-bis(4-aminophenoxy)benzene, 4,4'-bis(3-aminophenoxy)benzene, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diaminobiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-bis(trifluoromethyl)biphenyl, or 4,4'-bis(4-aminophenoxy)biphenyl.

5. The method for preparing an adhesive material as described in claim 1, characterized in that, In step (1), the organic solvent is selected from one or more of N,N-dimethylacetamide, N,N-dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, acetone, acetonitrile, and dimethyl sulfoxide.

6. The method for preparing an adhesive material as described in claim 1, characterized in that, The chemical imidizing agent in step (2) is a mixture of acetic anhydride and pyridine.

7. The method for preparing an adhesive material as described in claim 1, characterized in that, The imidization reaction time in step (2) is 5-7 hours.

8. The method for preparing an adhesive material as described in claim 1, characterized in that, In step (2), the precipitate is one or more of deionized water, methanol, ethanol, isopropanol, propanol, butanol or isobutanol.

9. An adhesive material, characterized in that, It is prepared by the method of any one of claims 1-8.

10. The application of an adhesive material as described in claim 9, characterized in that, Adhesive materials are used in the field of silicone glass.