Preparation method of thermosetting inorganic pressure-sensitive adhesive film capable of being cured in high-vacuum ultralow-temperature alternating environment

Abstract

The invention discloses a preparation method of a curable thermosetting inorganic pressure-sensitive adhesive film in a high-vacuum ultralow-temperature alternating environment, and relates to the technical field of pressure-sensitive adhesive films. The invention aims to solve the problems of poor pressure sensitivity and short pot life of the existing inorganic adhesive film. The method comprises the following steps: mixing an inorganic aluminosilicate porous material and silicon dioxide whiskers, and fully dispersing to obtain a phosphate curing agent; uniformly stirring the titanate modified aluminum dihydrogen phosphate resin and a phosphate curing agent to obtain a phosphate adhesive; the preparation method comprises the following steps: carrying out vacuum defoaming on a phosphate adhesive, and coating one surface of ethylene propylene diene monomer rubber with the phosphate adhesive at 23-27 DEG C by adopting a precision coating machine, so as to obtain the thermosetting inorganic pressure-sensitive adhesive film which can be cured in the high-vacuum ultralow-temperature alternating environment. According to the preparation method, the thermosetting inorganic pressure-sensitive adhesive film capable of being cured in the high-vacuum ultralow-temperature alternating environment can be obtained.

Description

Technical Field

[0001] This invention relates to the field of pressure-sensitive adhesive film technology, specifically to a method for preparing a thermosetting inorganic pressure-sensitive adhesive film that can be cured under high vacuum and ultra-low temperature alternating environment. Background Technology

[0002] Orbiting the space station in a high vacuum (≤10 -3 The need for rapid repair of high-temperature resistant materials in low-orbit space environments with high and low temperature alternation (-80℃~10℃) requires the following three key performance characteristics: First, it must possess a certain degree of pressure sensitivity to facilitate convenient on-orbit operation and establish rapid positioning and adhesion to the interface being repaired; second, it must be able to complete an effective curing reaction with the surface being repaired under high vacuum and rapid high and low temperature alternation conditions to form a stable and reliable bonding interface; third, it must have a long service life to ensure stable performance during on-orbit storage, transportation, and construction windows.

[0003] Currently, emerging inorganic adhesive films have good application potential in this field, but existing inorganic adhesive films still have two major technical bottlenecks: insufficient pressure sensitivity and short pot life, which restrict their further development and application in the repair of high-temperature resistant materials in the space field. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of poor pressure sensitivity and short pot life of existing inorganic adhesive films, and to provide a method for preparing a thermosetting inorganic pressure-sensitive adhesive film that can be cured under high vacuum and ultra-low temperature alternating environment.

[0005] A method for preparing a thermosetting inorganic pressure-sensitive adhesive film that can be cured under high vacuum and ultra-low temperature alternating environment, comprising the following steps:

[0006] Step S1: Prepare titanate-modified aluminum dihydrogen phosphate resin;

[0007] Phosphoric acid and titanate coupling agent were mixed and placed in a reflux condenser. The mixture was refluxed until the solution was clear. After stirring, aluminum hydroxide powder was added and the mixture was kept under reflux for 19-20 minutes. After the reaction was completed, the mixture was cooled to room temperature to obtain titanate-modified aluminum dihydrogen phosphate resin.

[0008] Step S2: Prepare inorganic aluminosilicate porous materials;

[0009] Boehmite was added to a sodium hydroxide solution, and tetraethylammonium hydroxide was added under continuous stirring to obtain a mixture. Tetraethyl orthosilicate was added dropwise to the mixture and stirred until homogeneous to obtain a gel. The gel was subjected to hydrothermal reaction at 110-130℃ for 20-30 min. After centrifugation and washing, the product was dried and then kept at 500-600℃ for 3.9-4.1 h to obtain an inorganic aluminosilicate porous material.

[0010] Step S3: preparing a phosphate curing agent;

[0011] The inorganic aluminosilicate porous material obtained in step S2 and the silicon dioxide whisker are mixed and fully dispersed to obtain the phosphate curing agent;

[0012] Step S4: preparing a phosphate adhesive;

[0013] The titanate-modified aluminum dihydrogen phosphate resin obtained in step S1 and the phosphate curing agent obtained in step S3 are uniformly stirred to obtain the phosphate adhesive;

[0014] Step S5: preparing a phosphate pressure-sensitive adhesive film for a high-vacuum ultra-low-temperature alternating environment;

[0015] After the phosphate adhesive obtained in step S4 is vacuum degassed, one side of the ethylene-propylene-diene rubber is coated with the phosphate adhesive at 23-27 DEG C using a precision coater to obtain a thermosetting inorganic pressure-sensitive adhesive film that can be cured in a high-vacuum ultra-low-temperature alternating environment, with a thickness of 0.15-0.2 mm.

[0016] Principle of the application:

[0017] In view of the two technical bottlenecks of insufficient pressure sensitivity and short pot life of existing inorganic adhesive films, the application innovates through the technology of inorganic adhesive film pressure-sensitive molecular regulation by titanate modification and the technology of inorganic porous material vacuum slow release, breaks through the bottleneck of low curing degree and poor mechanical properties of existing inorganic adhesive films in a high-vacuum / high-temperature alternating environment, and prepares a thermosetting inorganic pressure-sensitive adhesive film that can be cured in a high-vacuum / high-temperature alternating environment, which can meet the repair needs of high-temperature-resistant structures in space low-orbit high-vacuum (≤10 -3 Pa) and high-temperature alternating (-80 DEG C-10 DEG C) complex environments.

[0018] Advantages of the application:

[0019] (1) The pressure-sensitive performance of the inorganic adhesive film mainly depends on the movement ability of the inorganic resin molecular chain segment and the cohesive strength of the adhesive layer. In the application, the titanate acts as a coupling agent by inserting a long alkyl chain between the phosphate resin molecular skeleton to realize the dual regulation mechanism of "cohesion enhancement-chain segment activation": on the one hand, the long alkyl chain forms crosslinking with the resin matrix, significantly increasing the cohesive strength and crosslinking density of the adhesive layer; on the other hand, the steric hindrance effect of the long alkyl chain weakens the original strong interaction forces such as hydrogen bonds and ionic bonds between resin molecules, effectively reducing the rotation potential barrier of the chain segment movement, and greatly improving the chain segment movement. The enhancement of the movement of the chain segment optimizes the deformation and interface fitting ability of the adhesive film under external force. Through the synergy at the molecular level, the macro pressure-sensitive performance of the inorganic adhesive film is significantly improved, specifically manifested as the synchronous enhancement of the initial adhesion and the bonding strength.

[0020] (2) The inorganic aluminosilicate porous material in the present application can lock part of water molecules and aluminum ions and other key reaction components in the pore channels through physical adsorption in the colloidal preparation stage, delay the polycondensation reaction rate, and significantly prolong the pot life. When the system enters a vacuum and high-low temperature alternating environment, the adsorbed components are released from the pore channels in a controlled manner when the external pressure and high-low temperature change, the curing process is controlled, and the pot life of the adhesive is significantly prolonged.

[0021] The present application can obtain a preparation method of a thermosetting inorganic pressure-sensitive adhesive film that can be cured in a high-vacuum super-low-temperature alternating environment. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The SEM image of the inorganic aluminosilicate porous material prepared in Example 1 is shown. DETAILED DESCRIPTION

[0023] Specific embodiment one: a preparation method of a thermosetting inorganic pressure-sensitive adhesive film that can be cured in a high-vacuum super-low-temperature alternating environment, which is carried out according to the following steps:

[0024] Step S1: preparing a titanium ester modified aluminum dihydrogen phosphate resin;

[0025] The phosphoric acid and titanium ester coupling agent are mixed and placed in a condensation reflux device, and refluxed until the solution is clear. After continuous stirring, aluminum hydroxide powder is added, and the reflux state is maintained for continuous reaction for 19-20 min. After the reaction is completed, it is cooled to room temperature to obtain a titanium ester modified aluminum dihydrogen phosphate resin;

[0026] Step S2: preparing an inorganic aluminosilicate porous material;

[0027] The pseudo-boehmite is added to a sodium hydroxide solution, and tetraethylammonium hydroxide is added under continuous stirring to obtain a mixed solution. The tetraethyl orthosilicate is added dropwise to the mixed solution, and after uniform stirring, a gel is obtained. The gel is hydrothermally reacted at 110-130℃ for 20-30 min. After centrifugal separation, the obtained product is washed and dried, and then heat treated at 500-600℃ for 3.9-4.1 h to obtain an inorganic aluminosilicate porous material;

[0028] Step S3: preparing a phosphate curing agent;

[0029] The inorganic aluminosilicate porous material obtained in step S2 and the silicon dioxide whisker are mixed and dispersed to obtain a phosphate curing agent;

[0030] Step S4: preparing a phosphate adhesive;

[0031] The titanate modified aluminum dihydrogen phosphate resin obtained in step S1 is stirred uniformly with the phosphate curing agent obtained in step S3 to obtain a phosphate adhesive;

[0032] Step S5: preparation of a phosphate pressure-sensitive adhesive film for high-vacuum ultra-low-temperature alternating environment;

[0033] The phosphate adhesive obtained in step S4 is vacuum-deaerated, and one side of the ethylene-propylene-diene rubber is coated with the phosphate adhesive at 23-27°C using a precision coater to obtain a thermosetting inorganic pressure-sensitive adhesive film that can be cured in a high-vacuum ultra-low-temperature alternating environment, with a thickness of 0.15-0.2 mm.

[0034] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the mass ratio of phosphoric acid to titanate coupling agent in step S1 is (4.99-5.01):(0.99-1.01); the molar ratio of phosphorus in the phosphoric acid to aluminum in the aluminum hydroxide powder is (2.99-3.01):(0.99-1.01).

[0035] The other steps are the same as in specific embodiment one.

[0036] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that the reflux temperature in step S1 is 78-82°C.

[0037] The other steps are the same as in specific embodiment one or two.

[0038] Specific embodiment four: the difference between this embodiment and one of specific embodiments one to three is that the continuous stirring time in step S1 is 20-30 min.

[0039] The other steps are the same as in specific embodiments one to three.

[0040] Specific embodiment five: the difference between this embodiment and one of specific embodiments one to four is that the ratio of the mass of pseudoboehmite, the volume of tetraethylammonium hydroxide, and the mass of tetraethyl orthosilicate in step S2 is (19.99-20.01) g:(17.99-18.01) mL:(49.99-50.01) g.

[0041] The other steps are the same as in specific embodiments one to four.

[0042] Specific embodiment six: the difference between this embodiment and one of specific embodiments one to five is that the mass ratio of pseudoboehmite to sodium hydroxide solution in step S2 is (19.99-20.01):(669.99-670.01).

[0043] The other steps are the same as in specific embodiments one to five.

[0044] Specific embodiment seven: the difference between this embodiment and one of the specific embodiments one to six is that the concentration of the sodium hydroxide solution is 0.49-0.51 mol / L.

[0045] The other steps are the same as those in the specific embodiments one to six.

[0046] Specific embodiment eight: the difference between this embodiment and one of the specific embodiments one to seven is that after centrifugal separation in step S2, the obtained product is washed with ethanol and deionized water for 3-5 times, and then dried at 60-80℃ for 11.9-12.1 h.

[0047] The other steps are the same as those in the specific embodiments one to seven.

[0048] Specific embodiment nine: the difference between this embodiment and one of the specific embodiments one to eight is that the mass ratio of the inorganic aluminosilicate porous material to the silicon dioxide whisker in step S3 is (9.99-10.01):(0.99-1.01).

[0049] The other steps are the same as those in the specific embodiments one to eight.

[0050] Specific embodiment ten: the difference between this embodiment and one of the specific embodiments one to nine is that the mass ratio of the titanate modified aluminum dihydrogen phosphate resin to the phosphate curing agent in step S4 is (0.99-1.01):(0.99-1.01).

[0051] The other steps are the same as those in the specific embodiments one to nine.

[0052] The beneficial effects of the present application are verified by the following examples:

[0053] Example 1: a preparation method of a thermosetting inorganic pressure-sensitive adhesive film that can be cured in a high-vacuum ultra-low-temperature alternating environment, which is carried out according to the following steps:

[0054] Step S1: preparation of a titanate modified aluminum dihydrogen phosphate resin;

[0055] Phosphoric acid and a titanate coupling agent are mixed and placed in a condensation reflux device, and refluxed at 82℃ until the solution is clear. After continuing to stir for 30 min, aluminum hydroxide powder is added, and the reflux state is maintained to continue the reaction for 20 min. After the reaction is completed, it is cooled to room temperature to obtain a titanate modified aluminum dihydrogen phosphate resin;

[0056] The mass ratio of the phosphoric acid to the titanate coupling agent is 5:1; and the molar ratio of phosphorus in the phosphoric acid to aluminum in the aluminum hydroxide powder is 3:1;

[0057] Step S2: preparation of an inorganic aluminosilicate porous material;

[0058] 20 g of boehmite was added to 670 g of sodium hydroxide solution (concentration of 0.5 mol / L), and 18 mL of tetraethylammonium hydroxide was added under continuous stirring to obtain a mixture. 50 g of tetraethyl orthosilicate was added dropwise to the mixture, and after stirring evenly, a gel was obtained. The gel was subjected to hydrothermal reaction at 120℃ for 30 min. After high-speed centrifugation, the product was washed 3-5 times with ethanol and deionized water to remove impurities. The obtained product was dried at 80℃ for 12 h, and then the powder was placed in a muffle furnace and kept at 600℃ for 4 h to obtain an inorganic aluminosilicate porous material.

[0059] Step S3: Prepare phosphate curing agent;

[0060] The inorganic aluminosilicate porous material obtained in step S2 is mixed with silica whiskers and then fully dispersed to obtain a phosphate curing agent.

[0061] The mass ratio of the inorganic aluminosilicate porous material to the silica whiskers is 10:1.

[0062] Step S4: Prepare phosphate adhesive;

[0063] After mixing the titanate-modified aluminum dihydrogen phosphate resin obtained in step S1 with the phosphate curing agent obtained in step S3, a phosphate adhesive is obtained.

[0064] The mass ratio of the titanate-modified aluminum dihydrogen phosphate resin to the phosphate curing agent is 1:1;

[0065] Step S5: Prepare a phosphate pressure-sensitive adhesive film for use in a high-vacuum, ultra-low temperature alternating environment;

[0066] After vacuum degassing, the phosphate adhesive obtained in step S4 is coated on one side of EPDM rubber using a precision coating machine at 25°C with EPDM rubber as the matrix. The film thickness is controlled to be about 0.15~0.2mm by adjusting the gap, resulting in a thermosetting inorganic pressure-sensitive adhesive film that can be cured under high vacuum and ultra-low temperature alternating environment.

[0067] Figure 1 This shows a SEM image of the inorganic aluminosilicate porous material prepared in Example 1; as shown. Figure 1 As shown, inorganic aluminosilicate porous materials are based on a robust framework constructed from silicon-oxygen tetrahedra. Aluminum replaces silicon through heterovalent substitution, forming a uniform sub-nanometer pore system in synergy. This unique microstructure endows the material with excellent physical adsorption capacity and superior thermal stability.

[0068] The thermosetting inorganic pressure-sensitive adhesive film prepared in this embodiment was used to bond high-temperature resistant materials (high-temperature resistant optical glass, high-temperature resistant phenolic composite material) under a thermal cycling condition of -80℃ to -10℃, 4 hours per cycle; 10 -3 After curing for 3 days under vacuum (Pa), various performance tests were conducted. The test results in Table 1 show that the thermosetting inorganic pressure-sensitive adhesive film prepared in this embodiment exhibits the following properties: room temperature shear strength ≥2.0 MPa, 500℃ shear strength ≥1.5 MPa, and 1000℃ shear strength ≥1.0 MPa for glass materials; room temperature shear strength ≥2.0 MPa and 400℃ shear strength ≥1.0 MPa for phenolic composite materials; pot life ≥12 hours; and ring initial tack ≥10 N. Compared with traditional aluminum phosphate adhesives, this thermosetting inorganic pressure-sensitive adhesive film shows significantly improved mechanical properties and pot life under high vacuum and alternating high and low temperature environments, while also meeting the performance requirements for repairing high-temperature resistant materials.

[0069] Traditional phosphate adhesives are prepared by mixing phosphoric acid and aluminum hydroxide, then placing the mixture in a reflux condenser and reacting it at 78-82°C until the solution becomes clear. The reaction is then continued with stirring for 20-30 minutes. After the reaction is complete, the mixture is cooled to room temperature to obtain aluminum dihydrogen phosphate resin. Aluminum oxide is then used as a phosphate curing agent and thoroughly mixed. Finally, the mixture is cured at 21-25°C for 47.99-48.01 hours to obtain the phosphate adhesive.

[0070] Table 1: Comparison of the bonding performance of the thermosetting inorganic pressure-sensitive adhesive film prepared in this embodiment and the traditional aluminum phosphate adhesive on high-temperature resistant materials;

[0071]

Claims

1. A method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment, characterized in that, The preparation method is carried out according to the following steps: Step S1: Prepare titanate-modified aluminum dihydrogen phosphate resin; Phosphoric acid and titanate coupling agent were mixed and placed in a reflux condenser. The mixture was refluxed until the solution was clear. After stirring, aluminum hydroxide powder was added and the mixture was kept under reflux for 19-20 minutes. After the reaction was completed, the mixture was cooled to room temperature to obtain titanate-modified aluminum dihydrogen phosphate resin. Step S2: Prepare inorganic aluminosilicate porous materials; Boehmite was added to a sodium hydroxide solution, and tetraethylammonium hydroxide was added under continuous stirring to obtain a mixture. Tetraethyl orthosilicate was added dropwise to the mixture and stirred until homogeneous to obtain a gel. The gel was then subjected to a hydrothermal reaction at 110-130℃ for 20-30 min. After centrifugation and washing, the product was dried and then kept at 500-600℃ for 3.9-4.1 h to obtain inorganic aluminosilicate porous material. Step S3: Prepare phosphate curing agent; The inorganic aluminosilicate porous material obtained in step S2 is mixed with silica whiskers and then fully dispersed to obtain a phosphate curing agent. Step S4: Prepare phosphate adhesive; After mixing the titanate-modified aluminum dihydrogen phosphate resin obtained in step S1 with the phosphate curing agent obtained in step S3, a phosphate adhesive is obtained. Step S5: Prepare a phosphate pressure-sensitive adhesive film for use in a high-vacuum, ultra-low temperature alternating environment; After vacuum degassing, the phosphate adhesive obtained in step S4 is coated onto one side of EPDM rubber using a precision coating machine at 23~27℃ to obtain a thermosetting inorganic pressure-sensitive adhesive film that can be cured under high vacuum and ultra-low temperature alternating environment with a thickness of 0.15~0.2 mm.

2. The method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment according to claim 1, characterized in that, The mass ratio of phosphoric acid to titanate coupling agent in step S1 is (4.99~5.01):(0.99~1.01); the molar ratio of phosphorus in phosphoric acid to aluminum in aluminum hydroxide powder is (2.99~3.01):(0.99~1.01).

3. The method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment according to claim 1, characterized in that, The reflux temperature in step S1 is 78~82℃.

4. The method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment according to claim 1, characterized in that, The stirring time in step S1 is 20-30 minutes.

5. The method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment according to claim 1, characterized in that, The ratio of the mass of boehmite, the volume of tetraethylammonium hydroxide, and the mass of tetraethyl orthosilicate in step S2 is (19.99~20.01) g : (17.99~18.01) mL : (49.99~50.01) g.

6. The method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment according to claim 1, characterized in that, The mass ratio of boehmite to sodium hydroxide solution in step S2 is (19.99~20.01):(669.99~670.01).

7. A method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment according to claim 1 or 6, characterized in that, The concentration of the sodium hydroxide solution is 0.49~0.51 mol / L.

8. The method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment according to claim 1, characterized in that, After centrifugation in step S2, the product is washed 3-5 times with ethanol and deionized water, and then dried at 60-80°C for 11.9-12.1 h.

9. The method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment according to claim 1, characterized in that, The mass ratio of the inorganic aluminosilicate porous material to the silica whiskers in step S3 is (9.99~10.01):(0.99~1.01).

10. The method for preparing a thermosetting inorganic pressure-sensitive adhesive film curable under high vacuum and ultra-low temperature alternating environment according to claim 1, characterized in that, The mass ratio of titanate-modified aluminum dihydrogen phosphate resin to phosphate curing agent in step S4 is (0.99~1.01):(0.99~1.01).

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