Adhesive for bonding phenyl siloxane rubber and metal as well as preparation method and application of adhesive

Abstract

The invention relates to the technical field of adhesives, in particular to an adhesive for bonding phenyl silicone rubber and metal as well as a preparation method and application of the adhesive for bonding the phenyl silicone rubber and the metal, and the adhesive comprises the following components in parts by weight: 85-100 parts of bismaleimide (BMI); 85 to 110 parts of hydrogen-containing phenyl silicone resin; 0.05 to 0.2 part of a latent platinum catalyst; 3-8 parts of a composite coupling agent; 5 to 15 parts of functional filler; and 0.5 to 2 parts of an antioxidant. According to the invention, the components in the core formula are synergistic: the BMI and the hydrogen-containing phenyl silicone resin are matched according to a specific proportion, and the bifunctional design of the composite coupling agent is combined, so that the interface bonding requirements of various metals such as steel and copper are met.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to an adhesive for bonding phenyl silicone rubber to metal, its preparation method, and its application. Background Technology

[0002] Phenyl silicone rubber is widely used in sealing / insulating components due to its excellent high temperature resistance (long-term 200℃+) and weather resistance, but its interfacial adhesion with metals such as steel, copper, and aluminum has always been a pain point in the industry. Existing two-component adhesives are cumbersome to use, require on-site mixing, and have a short pot life after mixing; Single-component adhesives mostly rely on physical adsorption, resulting in insufficient adhesion to silicone rubber (shear strength ≤2MPa) and low temperature-resistant bonding strength to metals (≤1MPa at 200℃). Traditional modified BMI adhesives are resistant to high temperatures, but they have poor compatibility with silicone rubber and cannot achieve high bond strength at the same time. It exhibits poor storage stability; its viscosity increases significantly after one month of storage at room temperature, and its performance degrades rapidly. Summary of the Invention

[0003] The purpose of this invention is to provide an adhesive for bonding phenyl silicone rubber to metals, its preparation method and application, thereby solving the technical problem of unreliable bonding of phenyl silicone rubber to metals such as steel and copper in the prior art.

[0004] This invention discloses an adhesive for bonding phenyl silicone rubber to metal, comprising, by weight: 85-100 parts of bismaleimide (BMI); 85-110 parts of hydrogen-containing phenyl silicone resin; 0.05-0.2 parts of latent platinum catalyst; 3-8 parts of composite coupling agent; 5-15 parts of functional filler; and 0.5-2 parts of antioxidant.

[0005] Furthermore, the bismaleimide is a bisphenol A diphenyl ether type BMI or a diphenylmethane type BMI.

[0006] Furthermore, the hydrogen-containing phenyl silicone resin has a hydrogen content of 0.6~1.2wt%, a phenyl content of ≥35%, and a uniform distribution of Si-H bonds. It exhibits good compatibility with phenyl silicone rubber.

[0007] Furthermore, the latent platinum catalyst is an encapsulated platinum-vinylsiloxane complex.

[0008] Furthermore, the latent platinum catalyst has a platinum content of 1000~3000ppm, is latent at room temperature, and is activated above 120℃.

[0009] Furthermore, the composite coupling agent is a bifunctional composite coupling agent.

[0010] Furthermore, the bifunctional groups of the bifunctional coupling agent are respectively targeted at metals and silicone rubber.

[0011] Furthermore, the functional group for metals is an aminosilane, and the functional group for silicone rubber is a vinylsilane or a phenylsilane.

[0012] Furthermore, the weight ratio of the functional groups targeting the metal to the functional groups targeting the silicone rubber is 1:1 to 2:1.

[0013] Furthermore, the functional filler is nano-silica and alumina in a weight ratio of 1:2 to 1:3.

[0014] Furthermore, the alumina is treated with a titanate coupling agent.

[0015] Furthermore, the antioxidant is a hindered phenol or a phosphite, which improves aging resistance.

[0016] A method for preparing an adhesive for bonding phenyl silicone rubber to metal includes the following steps: premixing bismaleimide with hydrogen-containing phenyl silicone resin; Then, add the latent platinum catalyst, composite coupling agent, functional filler, and antioxidant in sequence, and stir. The product is obtained after vacuum degassing.

[0017] Furthermore, the prepared product is then sealed and stored.

[0018] Application of an adhesive for bonding phenyl silicone rubber to metal, specifically for the dual-interface bonding of phenyl silicone rubber and metal.

[0019] Furthermore, the metal is steel or copper.

[0020] Furthermore, the surfaces of the parts to be bonded are pretreated before bonding, and then adhesive is applied and cured after bonding.

[0021] Application scenarios include: high-temperature bonding of phenyl silicone rubber seals to steel brackets / copper wires in aerospace engine nacelles; high-temperature resistant bonding of phenyl silicone rubber insulating components to steel shells / copper joints in turbochargers; and high-temperature resistant sealing bonding of phenyl silicone rubber gaskets to steel flanges / copper connectors in industrial furnaces.

[0022] Compared with the prior art, the beneficial effects of the present invention are: 1. Synergistic effect of core formulation components in this invention: By combining BMI with hydrogen-containing phenyl silicone resin in a specific ratio, and using the bifunctional design of the composite coupling agent, it is suitable for the interfacial bonding requirements of various metals such as steel and copper. 2. Precise selection of the latent platinum catalyst of the present invention: an encapsulated platinum-vinylsiloxane complex is selected, which ensures both room temperature storage stability and high-temperature rapid activation and curing, without the need for a two-component ratio; 3. Optimization of the proportions of the formulation components in this invention: Defining the weight range of each component to ensure a balance between high bonding strength, high temperature resistance and storage stability; 4. This invention achieves high bonding strength at the dual interface between phenyl silicone rubber and metals such as steel and copper (room temperature shear ≥3MPa, 200℃ shear ≥2.5MPa). Single-component storage stability (viscosity change ≤10% after ≥3 months of sealed storage at room temperature); Maintain high temperature resistance (long-term operating temperature ≥200℃, short-term tolerance 300℃). Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] Example 1 This embodiment discloses an adhesive for bonding phenyl silicone rubber to metal, its preparation method, and its application. The raw material composition (by weight) is as follows: Bismaleimide (BMI), bisphenol A diphenyl ether type, CAS 3292-90-2, 100 parts; Hydrogen-containing phenyl silicone resin: hydrogen content 0.9wt%, phenyl content 38%, uniform Si-H distribution, 95 parts; Latent platinum catalyst: encapsulated platinum-vinylsiloxane complex, platinum content 2000 ppm, 0.1 parts; Composite coupling agent: KH550 (aminosilane): A-171 (vinylsilane) = 1:1, 4 parts; Functional filler: Hydrophobic vapor phase SiO2: titanate coupling agent treated Al2O3 = 1:2, 10 parts; Antioxidant: Hindered phenols 1010, 1 part; Preparation steps Premixed resin: Add BMI and hydrogen-containing phenyl silicone resin to the reactor, stir at low speed at 70°C for 45 min, and cool to room temperature; Additives: Add latent platinum catalyst, composite coupling agent, functional filler and antioxidant in sequence, and stir at 500 rpm for 1.5 h at room temperature; Vacuum degassing: -0.096MPa vacuum degassing for 25 minutes; Sealed storage: Enclosed in aluminum foil bags, store at room temperature away from light.

[0025] Curing process Surface pretreatment: phenyl silicone rubber (ethanol wiping + plasma activation), steel / copper (sandblasting + acetone degreasing); Coating thickness: 30μm; Curing conditions: 170℃ / 0.5h.

[0026] Performance test results Test items: steel-phenyl silicone rubber, copper-phenyl silicone rubber Room temperature bond shear strength: 3.3 MPa Bond shear strength at 200℃: 2.7 MPa - 2.6 MPa Viscosity changed by 8% after 3 months of storage at room temperature. Strength retention rate after long-term aging at 200℃ for 72 hours: 90%-88%. Example 2 (High-Toughness Formula) An adhesive for bonding phenyl silicone rubber to metal, its preparation method and application, raw material composition (by weight): BMI: bisphenol A diphenyl ether type, 100 parts; Hydrogen-containing phenyl silicone resin: 1.2wt% hydrogen content, 35% phenyl content, 110 parts; Latent platinum catalyst: encapsulated platinum-vinylsiloxane complex, platinum content 3000 ppm, 0.2 parts; Composite coupling agent: KH550:A-171 = 2:1, 6 parts; Functional filler: hydrophobic vapor phase SiO2: titanate Al2O3 = 1:3, 15 parts; Antioxidant: 1010+168 (1:1), 2 parts.

[0027] Preparation steps and curing process Same as Example 1 Performance test results Test items: steel-phenyl silicone rubber, copper-phenyl silicone rubber Room temperature bond shear strength: 3.6 MPa - 3.5 MPa Bond shear strength at 200℃: 3.1 MPa - 2.8 MPa Viscosity changed by 9% after 3 months of storage at room temperature. Elongation at break: 7.2% - 7% Strength retention rate after long-term aging at 200℃ for 72 hours: 85%-83%. Example 3 (Low-cost formulation) An adhesive for bonding phenyl silicone rubber to metal, its preparation method and application, raw material composition (parts by weight), BMI: diphenylmethane type (CAS13676-54-5), 100 parts Hydrogen-containing phenyl silicone resin: hydrogen content 0.6wt%, phenyl content 40%, 85 parts Latent platinum catalyst: encapsulated platinum-vinylsiloxane complex, platinum content 1000 ppm, 0.05 parts; Composite coupling agent: KH550: phenylsilane (A-152) = 1:1, 3 parts; Functional filler: Titanate-treated Al2O3 (single), 15 parts; Antioxidant: 168, 0.5 parts.

[0028] Preparation steps and curing process Same as Example 1 Performance test results Test item: steel-phenyl silicone rubber Room temperature bond shear strength: 3.0 MPa Bond shear strength at 200℃: 2.5 MPa Viscosity changed by 10% after 3 months of storage at room temperature. Strength retention rate was 90%-89% after long-term aging at 200℃ for 72 hours. Comparative Example 1 (Existing one-component adhesive) Epoxy resin (E-51): Conventional bisphenol A type, 100 parts Latent curing agent (dicyandiamide): 8 parts Coupling agent (KH-560): 3 parts Fumed silica: 5 parts Propylene glycol methyl ether acetate: 5 parts Preparation steps Mixing the main body: Add epoxy resin (E-51) to the mixing tank, stir at low speed at room temperature for 10 minutes, add diluent, and continue stirring for 10 minutes until homogeneous; Additives: Add latent curing agent, coupling agent and functional filler in sequence, stir at 400 rpm for 1 hour at room temperature until there are no obvious particles and the system is homogeneous; Vacuum degassing: -0.09MPa vacuum degassing for 20 minutes to remove air bubbles from the system; Sealed storage: Enclosed in aluminum foil bags, store at room temperature away from light.

[0029] The curing process is the same as in Example 1. Performance test results Test items: steel-phenyl silicone rubber, copper-phenyl silicone rubber Room temperature bond shear strength: 1.7 MPa - 1.5 MPa The bond shear strength at 200℃ is 0.6 MPa. Viscosity changed by 30% after 3 months of storage at room temperature. Strength retention rate after long-term aging at 200℃ for 72 hours: 70% Comparative Example 2 (Existing Two-Component Adhesive) Component A Epoxy resin (E-44): Conventional bisphenol A type, 100 parts Reactive diluent (benzyl glycidyl ether): 10 parts Coupling agent (KH-550): 2 parts Fumed silica: 4 parts Titanium dioxide: 3 parts Component B (curing agent phase) Curing agent (diethylenetriamine): 12 parts Curing accelerator (DMP-30): 0.5 parts Propylene glycol methyl ether acetate: 3 parts Preparation steps Preparation of Component A: Add epoxy resin (E-44) to a mixing tank and stir at low speed at room temperature for 10 min. Add reactive diluent and continue stirring for 15 min until the system is transparent and uniform. Add coupling agent, fumed silica and titanium dioxide in sequence, and stir at 350 rpm at room temperature for 1.5 h until there are no obvious particles and the system is fine and uniform. Degas under -0.09 MPa vacuum for 25 min to remove air bubbles from the system and discharge for later use.

[0030] Preparation of component B: Add the curing agent (diethylenetriamine) to the mixing tank and stir at low speed at room temperature for 5 minutes. Add the curing accelerator and diluent, and continue stirring for 10 minutes until completely dissolved and mixed evenly. Discharge and set aside.

[0031] Curing process: Mix component A and component B at a mass ratio of 10:1, stir at room temperature for 3-5 minutes until uniform, and immediately perform bonding operations; store components A and B separately in sealed containers to avoid premature reaction.

[0032] Curing time is 24 hours at room temperature or 2 hours at 80°C (the curing process can be adapted to Example 1 and adjusted according to actual needs).

[0033] Performance test results Performance test results Test items: steel-phenyl silicone rubber, copper-phenyl silicone rubber Room temperature bond shear strength: 2.5 MPa - 2.4 MPa Bond shear strength at 200℃: 1.5 MPa - 1.6 MPa Viscosity changed by 15% after 3 months of storage at room temperature. Strength retention rate after long-term aging at 200℃ for 72 hours: 78%-79%. Comparative Example 3 (Traditional BMI Adhesive) Bismaleimide (BMI): Conventional bismaleimide resin, 100 parts Curing agent (4,4'-diaminodiphenyl sulfone, DDS): 18 parts Coupling agent (KH-560): 3 parts Fumed silica: 5 parts N,N-Dimethylformamide (DMF): 8 parts Preparation steps Mixing the main body: Add conventional BMI resin to a stirred tank, heat to 60℃ and stir at low speed for 15 minutes, add diluent N,N-dimethylformamide (DMF) and continue stirring for 15 minutes until the resin is completely dissolved and the system is homogeneous; Additives: Add curing agent (DDS), coupling agent (KH-560), and functional filler (fumed silica) in sequence, stir at 60℃ and 400rpm for 1.5h until there are no obvious particles and the system is uniform and viscous; Vacuum degassing: -0.09MPa vacuum degassing for 20 minutes to remove air bubbles and trace amounts of diluent volatiles from the system; Sealed storage: Packed in aluminum foil bags, store at room temperature away from light to prevent moisture absorption and premature curing.

[0034] The curing process is the same as in Example 1. Performance test results Performance test results Test items: steel-phenyl silicone rubber, copper-phenyl silicone rubber Room temperature bond shear strength: 1.5 MPa The bond shear strength at 200℃ is 0.7 MPa. Viscosity changed by 25% after 3 months of storage at room temperature. Strength retention rate after long-term aging at 200℃ for 72 hours: 88%-89%. Comparative Example 4 The only change from Example 1 is that the BMI is adjusted to 150.

[0035] Raw material composition (by weight) Bismaleimide (BMI), bisphenol A diphenyl ether type, CAS 3292-90-2, 150 parts; Hydrogen-containing phenyl silicone resin: hydrogen content 0.9wt%, phenyl content 38%, uniform Si-H distribution, 95 parts; Latent platinum catalyst: encapsulated platinum-vinylsiloxane complex, platinum content 2000 ppm, 0.1 parts; Composite coupling agent: KH550 (aminosilane): A171 (vinylsilane) = 1:1, 4 parts; Functional filler: Hydrophobic vapor phase SiO2: titanate coupling agent treated Al2O3 = 1:2, 10 parts; Antioxidant: Hindered phenols 1010, 1 part; The preparation steps and curing process are the same as in Example 1.

[0036] Performance test results Test items: steel-phenyl silicone rubber, copper-phenyl silicone rubber Room temperature bond shear strength: 2.5 MPa - 2.4 MPa Bond shear strength at 200℃: 1.6 MPa Viscosity changed by 8% after 3 months of storage at room temperature. Strength retention rate after long-term aging at 200℃ for 72 hours: 85% Comparative Example 5 The only change in Example 1 was that the amount of hydrogen-containing phenyl silicone resin was adjusted to 60 parts.

[0037] Raw material composition (by weight) Bismaleimide (BMI), bisphenol A diphenyl ether type, CAS 3292-90-2, 100 parts; Hydrogen-containing phenyl silicone resin: hydrogen content 0.9wt%, phenyl content 38%, uniform Si-H distribution, 60 parts; Latent platinum catalyst: encapsulated platinum-vinylsiloxane complex, platinum content 2000 ppm, 0.1 parts; Composite coupling agent: KH550 (aminosilane): A171 (vinylsilane) = 1:1, 4 parts; Functional filler: Hydrophobic vapor phase SiO2: titanate coupling agent treated Al2O3 = 1:2, 10 parts; Antioxidant: Hindered phenols 1010, 1 part; The preparation steps and curing process are the same as in the original example 1. Performance test results Test items: steel-phenyl silicone rubber, copper-phenyl silicone rubber Room temperature bond shear strength: 2.1 MPa - 2.2 MPa Bond shear strength at 200℃: 1.5 MPa Viscosity changed by 8% after 3 months of storage at room temperature. Strength retention rate is 90% after long-term aging at 200℃ for 72 hours. Comparative Example 6 The only change in Example 1 was that the composite coupling agent was changed to a single coupling agent, KH550.

[0038] Raw material composition (by weight): Bismaleimide (BMI), bisphenol A diphenyl ether type, CAS 3292-90-2, 100 parts; Hydrogen-containing phenyl silicone resin: hydrogen content 0.9wt%, phenyl content 38%, uniform Si-H distribution, 95 parts; Latent platinum catalyst: encapsulated platinum-vinylsiloxane complex, platinum content 2000 ppm, 0.1 parts; Coupling agent: KH550 (aminosilane), 4 parts; Functional filler: Hydrophobic vapor phase SiO2: titanate coupling agent treated Al2O3 = 1:2, 10 parts; Antioxidant: Hindered phenols 1010, 1 part; The preparation steps and curing process are the same as in Example 1. Test items: steel-phenyl silicone rubber, copper-phenyl silicone rubber Room temperature bond shear strength: 1.7 MPa - 1.6 MPa The bond shear strength at 200℃ is 0.9 MPa. Viscosity changed by 8% after 3 months of storage at room temperature. Strength retention rate after long-term aging at 200℃ for 72 hours: 85% Example Conclusion The three embodiments of the present invention all meet the requirements of ≥3MPa at room temperature and ≥2.5MPa at 200℃ for the bonding strength between metals such as steel and copper and phenyl silicone rubber, which is significantly better than the prior art; The viscosity change is ≤10% after 3 months of storage at room temperature, which solves the problem of poor storage stability in existing technologies. Single-component adhesives require no mixing and are easy to process, overcoming the limitations of existing two-component adhesives. It is compatible with various metals such as steel and copper, making it suitable for a wider range of applications.

[0039] The above are the embodiments listed in this example. However, this example is not limited to the optional embodiments described above. Those skilled in the art can arbitrarily combine the above methods to obtain other various embodiments. Anyone can derive other various forms of embodiments based on the inspiration of this example. The above specific embodiments should not be construed as limiting the scope of protection of this example. The scope of protection of this example should be determined by the claims, and the specification can be used to interpret the claims.

Claims

1. An adhesive for bonding phenyl silicone rubber to metal, characterized in that: It includes, by weight, 85-100 parts of bismaleimide; Hydrogen-containing phenyl silicone resin: 85~110 parts; latent platinum catalyst: 0.05~0.2 parts; composite coupling agent: 3~8 parts; functional filler: 5~15 parts; antioxidant: 0.5~2 parts.

2. The adhesive for bonding phenyl silicone rubber to metal according to claim 1, characterized in that: The bismaleimide is a bisphenol A diphenyl ether type BMI or a diphenylmethane type BMI; And / or, the hydrogen-containing phenyl silicone resin has a hydrogen content of 0.6~1.2wt%, a phenyl content of ≥35%, and a uniform distribution of Si-H bonds; And / or, the latent platinum catalyst is an encapsulated platinum-vinylsiloxane complex; And / or, the composite coupling agent is a bifunctional composite coupling agent; And / or, the latent platinum catalyst has a platinum content of 1000~3000ppm, is latent at room temperature, and is activated above 120℃; And / or, the functional filler is nano-silica and alumina in a weight ratio of 1:2 to 1:

3.

3. The adhesive for bonding phenyl silicone rubber to metal according to claim 2, characterized in that: The bifunctional coupling agent has bifunctional groups targeting both metals and silicone rubber.

4. The adhesive for bonding phenyl silicone rubber to metal according to claim 3, characterized in that: The functional group for metals is aminosilane, and the functional group for silicone rubber is vinylsilane or phenylsilane.

5. The adhesive for bonding phenyl silicone rubber to metal according to claim 4, characterized in that: The weight ratio of the functional groups targeting metals to the functional groups targeting silicone rubber is 1:1 to 2:

1.

6. The adhesive for bonding phenyl silicone rubber to metal according to claim 2, characterized in that: The alumina is treated with a titanate coupling agent.

7. The adhesive for bonding phenyl silicone rubber to metal according to claim 1, characterized in that: The antioxidant is a hindered phenol or a phosphite.

8. A method for preparing an adhesive for bonding phenyl silicone rubber to metal according to any one of claims 1-7, characterized in that: The steps include: premixing bismaleimide with hydrogen-containing phenyl silicone resin; Then, add the latent platinum catalyst, composite coupling agent, functional filler, and antioxidant in sequence, and stir. The product is obtained after vacuum degassing.

9. The application of an adhesive for bonding phenyl silicone rubber to metal according to any one of claims 1-7, or an adhesive prepared by the method for preparing an adhesive for bonding phenyl silicone rubber to metal according to claim 8, characterized in that: Used for dual-interface bonding of phenyl silicone rubber and metal.

10. The application of the adhesive for bonding phenyl silicone rubber to metal according to claim 9, characterized in that: The metal is steel or copper.