Adhesive for thermal insulation layer in solid rocket engine, preparation method and application thereof

Abstract

The present invention relates to the technical field of solid engine adhesives, and discloses an adhesive for the inner thermal insulation layer of a solid rocket engine. The adhesive comprises the following raw materials by weight: 90-180 parts of silicone rubber, 10-30 parts of ablation-resistant filler, 20-40 parts of glass powder, 5-10 parts of polyborosiloxane, 4-8 parts of a cross-linking agent, 0.3-1 parts of an inhibitor, 0.5-1 parts of a tackifier, and 10-20 parts of a catalyst. Due to the synergistic effect of the polyborosiloxane, the ablation-resistant filler, and the glass powder, the adhesive has good high-temperature bonding performance and excellent ablation resistance, with an oxygen-acetylene line ablation rate of 0.8 mm / s to 1.0 mm / s. Under an environment of 350°C, the silicone rubber inner thermal insulation layer and the metal shell interface still adhere well. Also disclosed are a preparation method and application of the adhesive for the inner thermal insulation layer of a solid rocket engine. The adhesive for the inner thermal insulation layer of a solid rocket engine has a simple coating process, requiring only a one-time coating, and the next step can be carried out after coating, with a short cycle and no need for a long hot pre-pressing step.

Description

Technical Field

[0001] The present invention relates to the technical field of solid rocket engine adhesives, and in particular to an adhesive for an inner thermal insulation layer of a solid rocket engine, a preparation method thereof, and an application thereof. Background Art

[0002] A solid rocket motor is a high-performance rocket propulsion system consisting of a combustion chamber, propellant, igniter, and nozzle. The combustion chamber is a container for the propellant and also provides the combustion space, subject to high temperatures exceeding 3000°C and high-pressure combustion gases. The internal insulation layer of the combustion chamber is a layer of thermally insulating and protective material placed between the inner surface of the casing and the propellant. Its primary function is to remove most of the heat through its own decomposition and ablation, thereby slowing the transfer of high-temperature combustion gases to the casing, preventing the casing from reaching temperatures that threaten its structural integrity and ensuring proper engine operation. To ensure the bond between the motor casing and the internal insulation layer in solid rocket motors, a cured adhesive is typically used. During production, storage, and transportation, the adhesive layer of solid rocket motors is subject to a variety of complex loads and environmental conditions, resulting in weak bonds or debonding, which can reduce the reliability of the solid rocket motor and even lead to failure.

[0003] The thermal insulation layer within the combustion chamber is typically a silicone rubber inner insulation layer, and the silicone rubber is vulcanized silicone rubber. Vulcanized silicone rubber is an insulation material with excellent ablation resistance, smoke reduction, and storage properties. However, the prominent disadvantage of vulcanized silicone rubber is its low surface energy and poor adhesion, making it difficult to form a reliable bonding interface with the metal casing of a solid rocket engine. This has a significant negative impact on the application of vulcanized silicone rubber insulation layers. Conventional organic silicone adhesives lack ablation resistance and are prone to failure in high-temperature environments, limiting their application in bonding inner insulation layers. Invention patent CN118725817A discloses a heat-vulcanized silicone rubber adhesive with high bonding strength and good bonding stability. However, this adhesive lacks high-temperature resistance and ablation resistance. Invention patent CN119019976A discloses a two-component silicone rubber adhesive that can effectively bond metals and composite materials, but this adhesive lacks ablation resistance. In the "Analysis of Factors Affecting the Adhesive Performance of the Insulation Layer of Solid Rocket Engines", Chen Guohui et al. pointed out that when applying the adhesive, it is necessary to apply it multiple times and use hot air drying to remove the solvent. The process is relatively complicated and requires multiple applications and hot air drying. Invention patent CN104943184B discloses a method of using adhesive to stick the insulation layer sheet on the shell. This method requires a hot pre-pressing step, heating treatment, long pressurization time, and cumbersome process. Invention patent CN102632683B discloses a method for making manual insulation layer patches. This method can ensure the thickness and size of the manual insulation layer patches. However, the manual patch production method is inefficient and prone to defects such as bulging, pits, and debonding. It is easily eroded by hot air flow, resulting in failure of thermal protection and ultimately causing the combustion chamber to explode and disintegrate. Therefore, in the existing technology, the adhesives and bonding process methods for bonding the vulcanized silicone rubber inner insulation layer to the metal shell interface still have great defects. There is an urgent need for an adhesive that is both resistant to high temperatures and ablation (i.e., the oxygen-acetylene line ablation rate is less than 0.07 mm / s), has low viscosity during use, and has good coating and bonding process performance. Summary of the Invention

[0004] Based on the above, the purpose of the present invention is to provide an adhesive for the inner insulation layer of a solid rocket engine, a preparation method and an application thereof, which can bond the silicone rubber inner insulation layer to the interface of the metal shell, and has excellent ablation resistance and high-temperature bonding performance. At the same time, it has low viscosity and good coating and bonding process performance during use.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An adhesive for the inner thermal insulation layer of a solid rocket motor comprises the following raw materials in parts by mass:

[0007] 90~180 parts of silicone rubber

[0008] 10~30 parts of ablation-resistant filler

[0009] 20~40 parts glass powder

[0010] 5-10 parts of polyborosiloxane

[0011] 4~8 parts of cross-linking agent

[0012] 0.3~1 part of inhibitor

[0013] 0.5~1 part of constant viscosity thickener

[0014] 10-20 parts of catalyst;

[0015] The constant viscosity tackifier is synthesized by hydrosilylation reaction using phenyl tris(dimethylsiloxy)silane and cardanol polyoxyethylene ether as raw materials at a mass ratio of (2.5-3.5):1.

[0016] As a preferred solution for the adhesive for the thermal insulation layer of a solid rocket motor, the method for synthesizing the constant viscosity tackifier comprises the following steps:

[0017] Phenyltris(dimethylsiloxy)silane was added into a reactor equipped with a stirrer, a thermometer and a condensation reflux device;

[0018] Add nitrogen and raise the temperature to 80-90°C;

[0019] Add platinum catalyst and keep warm for a while, then slowly add cardanol polyoxyethylene ether dropwise;

[0020] After the addition is complete, start timing and allow the reaction to proceed for 2.5-3.5 hours;

[0021] The platinum catalyst includes a platinum-vinylsiloxane complex.

[0022] As a preferred embodiment of an adhesive for the thermal insulation layer of a solid rocket engine, the silicone rubber comprises one or more of methyl vinyl silicone rubber, methyl vinyl phenyl silicone rubber, methyl phenyl silicone rubber, para-phenylene silicone rubber, phenylene silicone rubber, and phenylene ether silicone rubber; and the viscosity of the silicone rubber is 500 to 50,000 mPa·s.

[0023] As a preferred embodiment of an adhesive for the thermal insulation layer of a solid rocket engine, the ablation-resistant filler includes one or more of mica powder, diatomaceous earth powder, kaolin, silica lime powder, modified silicon carbide nanopowder, zirconium oxide powder, magnesium carbonate, and aluminum oxide powder; the particle size of the ablation-resistant filler is below 600 mesh.

[0024] As a preferred solution for the adhesive for the thermal insulation layer in a solid rocket engine, the glass powder includes D233.

[0025] As a preferred solution for the adhesive for the thermal insulation layer of a solid rocket engine, the viscosity of the polyborosiloxane is 500-5000 mPa·s.

[0026] As a preferred embodiment of the adhesive for the thermal insulation layer in a solid rocket engine, the crosslinking agent includes hydrogenated silicone oil; the inhibitor includes one or more of 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, and 3-phenyl-1-butyn-3-ol.

[0027] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0028] Silicone rubber, ablation-resistant filler, glass powder, and polyborosiloxane are placed in a mixing barrel of a double planetary mixer according to a certain proportion, and vacuum degassing treatment is performed to prepare a base material;

[0029] Take a certain amount of base material and put it into the mixing barrel of the double planetary mixer. Add the crosslinking agent, inhibitor and constant viscosity thickener into the mixing barrel of the double planetary mixer according to the proportion and stir evenly to prepare component A.

[0030] Take a certain amount of base material and put it into the mixing barrel of a double planetary mixer, add the catalyst according to the proportion, and stir evenly to obtain component B;

[0031] Component A and component B are uniformly mixed in a mass ratio of (13-20):1 to obtain an adhesive for the thermal insulation layer of a solid rocket engine.

[0032] The mass ratio of the base material in the component A to the component B is 126: (10-20).

[0033] As a preferred embodiment of the method for preparing an adhesive for the thermal insulation layer of a solid rocket engine, the vacuum degree of the vacuum degassing treatment is -0.08 to -0.1 MPa, and the mixing time of the degassing treatment in the vacuum state is 0.5 to 2 hours.

[0034] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0035] Use sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface. Then use ethyl acetate to clean the grinded area and let it air-dry at room temperature.

[0036] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0037] Applying epoxy silane coupling agent to the treated bonding area of ​​the inner insulation layer head preform and the bonding area of ​​the inner profile of the metal shell, and leaving them to air at room temperature;

[0038] Use a brush to pick up the adhesive and evenly apply the adhesive to the bonding area of ​​the inner insulation layer head preform and the bonding area of ​​the inner surface of the metal shell after the epoxy silane coupling agent is applied;

[0039] Laminating the inner insulation layer head prefabricated part coated with the adhesive to the inner surface of the metal shell, and installing the airbag and airbag tooling;

[0040] Use the airbag to slowly pressurize to a certain pressure, and the excess adhesive overflows. Then the airbag and the bonded inner insulation layer head preform and the metal shell are transported to the heating device together, heated and cooled to complete the bonding of the inner insulation layer and the metal shell.

[0041] As a preferred solution for the application of adhesive in the thermal insulation layer of a solid rocket engine, the adhesive has a coating thickness of 0.02mm~0.05mm; when the airbag is pressurized, the required maintaining pressure is 0.3MPa~0.5MPa, the pressurization time is 5min-15min, and after heating treatment, the pressurization time is 0.5h-1.5h.

[0042] The beneficial effects of the present invention are:

[0043] The present invention provides an adhesive for the inner thermal insulation layer of a solid rocket engine. The adhesive exhibits excellent high-temperature bonding properties through the synergistic effects of polyborosiloxane, ablation-resistant fillers, and glass powder. The ablation-resistant fillers, such as mica and kaolin, in the adhesive system act as a framework during heating, and then, under the action of the glass powder, synergistically form a ceramic-like structure. The glass powder has an excellent ceramic-forming effect, softening and melting above 300°C, bonding the mica, kaolin, and other materials together to form a continuous ceramic structure, resulting in the adhesive's excellent high-temperature resistance. After bonding the inner thermal insulation layer to metal in a high-temperature environment of 350°C, the results of peeling the inner thermal insulation layer demonstrated excellent adhesive performance. Furthermore, the adhesive exhibited an oxy-acetylene ablation rate of ≤0.07 mm / s, demonstrating excellent ablation resistance. Polyborosiloxanes also have a certain self-adhesive effect on silicone rubber. The electron orbit of the B atom tends to be electron-deficient, and the oxygen atom in the Si-O bond provides a pair of electrons to form a coordination bond with the B atom. The bond energies of the BO bond and Si-O are 537.6 kJ / mol and 422.5 kJ / mol, respectively, which are much higher than the bond energy of ordinary organosiloxanes. This makes polyborosiloxane have higher thermal stability at high temperatures, thereby exhibiting excellent bonding properties at high temperatures.

[0044] The adhesive for the inner insulation layer of a solid rocket engine provided by the present invention has excellent high-temperature resistance and ablation resistance, with an oxygen-acetylene line ablation rate of less than 0.07 mm / s. The adhesive has good high-temperature bonding performance, and even at 350°C, the interface between the silicone rubber inner insulation layer and the metal shell is still well bonded. At the same time, due to the low viscosity of the adhesive, the coating process has excellent performance, and the application is simple, requiring only a one-time application, and the next step can be carried out after application; the cycle is short, and a long hot pre-pressing step is not required. The pressure is smaller than the conventional 0.6MPa~0.8MPa, requiring only 0.3MPa~0.5MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Schematic diagram of the oxygen-acetylene wire ablation principle. The red arrow indicates the direction of the ablation flame ablating the bonded test piece.

[0046] Figure 2 Schematic diagram of the bonding performance test results after the bonding test piece was ablated. DETAILED DESCRIPTION

[0047] To facilitate understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the present disclosure more thorough and comprehensive. Unless otherwise defined, all technical and scientific terms used in the present invention belong to the technical field of the present invention.

[0048] This embodiment provides an adhesive for the inner insulation layer of a solid rocket engine, comprising the following raw materials in parts by mass: 90 to 180 parts of silicone rubber, 10 to 30 parts of ablation-resistant filler, 20 to 40 parts of glass powder, 5 to 10 parts of polyborosiloxane, 4 to 8 parts of a cross-linking agent, 0.3 to 1 part of an inhibitor, 0.5 to 1 part of a constant viscosity tackifier, and 10 to 20 parts of a catalyst.

[0049] Specifically, the silicone rubber includes one or more of methyl vinyl silicone rubber, methyl vinyl phenyl silicone rubber, methyl phenyl silicone rubber, paraphenylene silicone rubber, phenylene silicone rubber and phenylene ether silicone rubber; and the viscosity of the silicone rubber is 500-50000 mPa·s.

[0050] Specifically, the ablation-resistant filler includes one or more of mica powder, diatomaceous earth powder, kaolin, silica lime powder, modified silicon carbide nanopowder, zirconium oxide powder, magnesium carbonate, and aluminum oxide powder; the ablation-resistant filler has a particle size of 600 mesh or less; the glass powder includes D233, which is molten at 300°C-350°C; and the viscosity of the polyborosiloxane is 500-5000 mPa·s. Due to the synergistic effect of the polyborosiloxane, the ablation-resistant filler, and the glass powder, the mica, kaolin, and other ablation-resistant fillers act as a skeleton during the heating process, and then, under the action of the glass powder, synergistically form a ceramic-like structure. The glass powder has an excellent ceramic-enhancing effect, softening and melting above 300°C, bonding the mica, kaolin, and other materials together to form a continuous ceramic structure, thus giving the adhesive excellent high-temperature resistance. Polyborosiloxanes also have a certain self-adhesive effect on silicone rubber. The electron orbit of the B atom tends to be electron-deficient, and the oxygen atom in the Si-O bond provides a pair of electrons to form a coordination bond with the B atom. The bond energies of the BO bond and Si-O are 537.6 kJ / mol and 422.5 kJ / mol, respectively, which are much higher than the bond energy of ordinary organosiloxanes. This makes polyborosiloxane have higher thermal stability at high temperatures, thereby exhibiting excellent bonding properties at high temperatures.

[0051] Specifically, the crosslinking agent includes hydrogen-containing silicone oil; the inhibitor includes one or more of 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, and 3-phenyl-1-butyn-3-ol.

[0052] The constant viscosity tackifier is homemade. Since the silicone rubber surface energy of the vulcanized silicone rubber inner insulation layer is low and the bonding performance is poor, it is difficult for the silicone rubber inner insulation layer to form a reliable bonding interface with the solid rocket engine metal shell using ordinary adhesives. The usual method to improve the bonding performance of adhesives is to add tackifiers to the adhesive, but adding conventional tackifiers to silicone rubber-based adhesives will increase the viscosity of the adhesive. In other words, if the constant viscosity tackifier in the formula of the solid rocket engine inner insulation layer adhesive of the present invention is replaced with a conventional tackifier, the viscosity of the prepared adhesive will be 250,000-400,000 mPa·s, making its processability worse. In particular, for coating the inside of the metal shell with adhesive, the excessive viscosity makes it difficult to coat, resulting in defects such as an uneven adhesive surface and difficulty in spreading, which cannot meet the use requirements at all. The adhesive of the present invention is added with a homemade constant viscosity tackifier, and the viscosity of the prepared adhesive is 100,000-200,000 mPa·s. If the homemade constant viscosity tackifier is removed according to the adhesive formula of the present invention, the viscosity of the prepared adhesive is also 100,000-200,000 mPa·s. This shows that adding the homemade constant viscosity tackifier does not increase the viscosity of the silicone rubber-based adhesive of the present invention, and can well meet the subsequent application bonding process requirements of bonding the insulation material and the metal (steel) shell in the solid rocket engine after curing.

[0053] The catalyst includes a platinum-vinylsiloxane complex.

[0054] This embodiment also provides a method for preparing an adhesive for the thermal insulation layer of a solid rocket engine, comprising the following steps:

[0055] (1) Silicone rubber, ablation-resistant filler, glass powder, and polyborosiloxane are placed in a mixing barrel of a double planetary mixer according to a certain proportion, and vacuum degassing treatment is performed to prepare a base material;

[0056] (2) Take a certain amount of base material and put it into the mixing barrel of a double planetary mixer, add the crosslinking agent, inhibitor, and constant viscosity thickener into the mixing barrel of the double planetary mixer in proportion, and stir evenly to prepare component A;

[0057] (3) Take a certain amount of base material and put it into the mixing barrel of a double planetary mixer, add the catalyst according to the proportion, and stir evenly to obtain component B;

[0058] (4) Component A and component B are mixed evenly in a mass ratio of (13-20):1, and subjected to vacuum degassing treatment to obtain an adhesive for the thermal insulation layer of a solid rocket engine.

[0059] Among them, the mass ratio of the base material in component A and component B is 126: (10~20).

[0060] Specifically, the vacuum degree in the vacuum state is -0.08 to -0.1 MPa, and the mixing time in the vacuum state is 0.5 to 2 hours.

[0061] This embodiment also provides an application of an adhesive for a thermal insulation layer in a solid rocket engine, comprising the following steps:

[0062] (1) Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface. Then use ethyl acetate to clean the polished area and let it dry at room temperature for 20-60 minutes.

[0063] (2) Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0064] (3) Apply epoxy silane coupling agent to the bonding area of ​​the treated inner insulation layer head prefabricated part and the bonding area of ​​the inner profile of the metal shell, and let it stand at room temperature for 20 minutes to 40 minutes;

[0065] (4) Use a brush to pick up the adhesive for the inner insulation layer of the solid rocket engine, and evenly apply the adhesive to the bonding area of ​​the inner insulation layer head preform after coating with epoxy silane coupling agent and the bonding area of ​​the inner surface of the metal shell;

[0066] (5) Fit the inner insulation layer head prefabricated part coated with adhesive to the inner surface of the metal shell, and install the airbag and airbag tooling;

[0067] (6) Use the airbag to slowly pressurize to a certain pressure, and the excess adhesive will overflow. Then, the airbag and the bonded inner insulation layer head prefabricated part and the metal shell are transferred to the heating device together. After heating treatment, cool down. The room temperature is raised to 150℃, the heating rate is 20℃ / min, and the temperature is kept for 1 hour. Then the temperature is lowered to room temperature to complete the bonding of the inner insulation layer and the metal shell.

[0068] Specifically, the adhesive coating thickness is 0.02mm~0.05mm; when the airbag is pressurized, the required pressure is 0.3MPa~0.5MPa, preferably 0.4MPa, and the pressurization time is 10min; during the heating treatment, the room temperature is raised to 150°C, the heating rate is 20°C / min, kept warm for 1h, and then cooled to room temperature.

[0069] The adhesive has a simple application process, requiring only one application, and the next step can be performed immediately after application. The cycle is short, and a long hot pre-pressing step is not required. The pressure is smaller than the conventional 0.6MPa~0.8MPa, requiring only 0.3MPa~0.5MPa.

[0070] The present invention will be further described below through specific examples. Example 1

[0071] An adhesive for the inner thermal insulation layer of a solid rocket motor, comprising the following components in parts by mass:

[0072] 150 parts of methyl vinyl silicone rubber (viscosity 500mPa·s), 30 parts of mica powder, 20 parts of D233 glass powder, 5 parts of polyborosiloxane (viscosity 600mPa·s), 6 parts of hydrogenated silicone oil, 0.5 parts of 3-phenyl-1-butyn-3-ol, 0.5 parts of constant viscosity tackifier, and 16 parts of platinum-vinylsiloxane complex.

[0073] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0074] 150 parts of methyl vinyl silicone rubber, 30 parts of mica powder, 20 parts of glass powder, and 5 parts of polyborosiloxane are placed in a mixing barrel of a double planetary mixer in that order, and the rubber is subjected to a vacuum degassing treatment to prepare a base material, wherein the vacuum degree of the vacuum state is -0.08 MPa to -0.1 MPa, and the vacuum state time is 5 min to 10 min;

[0075] 126 parts of the base material were placed in the mixing barrel of a double planetary mixer, and 6 parts of hydrogenated silicone oil and 0.5 parts of 3-phenyl-1-butyn-3-ol were added to the mixing barrel of the double planetary mixer and stirred evenly to prepare component A.

[0076] 15 parts of the base material were put into a mixing barrel of a double planetary mixer, and 16 parts of the platinum-vinylsiloxane complex were added and stirred evenly to prepare component B.

[0077] Component A and component B are packaged in plastic barrels respectively and sealed intactly, wherein the mixing mass ratio of component A to component B is 13:1, and the viscosity after mixing is 130210 mPa·s.

[0078] If conventional silicone rubber tackifier T907 produced by Wuhan Enric Materials Co., Ltd. is added and the other preparation methods are exactly the same, the viscosity of the prepared adhesive is 265830 mPa·s.

[0079] The measurement is carried out according to the method of "GB / T 2794-2022 Determination of viscosity of adhesives".

[0080] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0081] Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface;

[0082] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0083] The adhesive component A and component B are mixed in a mass ratio of 13:1, stirred evenly, and the adhesive is subjected to a vacuum degassing treatment with a vacuum degree of -0.08 MPa to -0.1 MPa and a vacuum state time of 5 min to 10 min to obtain the desired adhesive;

[0084] Use ethyl acetate to clean the polished area and let it dry at room temperature for 20 minutes to 60 minutes;

[0085] Apply epoxy silane coupling agent to the bonding area of ​​the inner insulation layer head prefabricated part, and apply epoxy silane coupling agent to the bonding area of ​​the inner surface of the metal shell, and let it air-dry at room temperature for 20 minutes to 40 minutes;

[0086] Use a brush to pick up the degassed adhesive and evenly apply it to the bonding area of ​​the inner insulation layer head prefabricated part and the inner surface bonding area of ​​the metal shell. The thickness of the adhesive should be controlled at 0.02mm~0.05mm.

[0087] Fit the inner insulation layer head prefabricated part to the inner surface of the metal shell; install the airbag and airbag tooling;

[0088] Slowly apply pressure using an airbag, maintaining it at 0.3 MPa until excess adhesive overflows. After 10 minutes, transfer the engine housing (including the head preform and airbag) to a heating device. Raise the temperature to 150°C at a rate of 20°C / min, hold for 1 hour, and then cool back to room temperature. This completes the bonding of the inner insulation layer to the metal housing. Example 2

[0089] An adhesive for the inner thermal insulation layer of a solid rocket motor, comprising the following components in parts by mass:

[0090] 180 parts of methyl vinyl phenyl silicone rubber (viscosity of 10000mPa·s), 20 parts of diatomaceous earth powder, 30 parts of D233 glass powder, 8 parts of polyborosiloxane (viscosity of 800mPa·s), 8 parts of hydrogenated silicone oil, 1 part of 3-phenyl-1-butyn-3-ol, 0.8 parts of constant viscosity tackifier, and 20 parts of platinum-vinylsiloxane complex.

[0091] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0092] 180 parts of methyl vinyl phenyl silicone rubber, 20 parts of diatomaceous earth powder, 30 parts of glass powder, and 8 parts of polyborosiloxane are placed in a mixing barrel of a double planetary mixer in that order, and the rubber is subjected to a vacuum degassing treatment to prepare a base material, wherein the vacuum degree of the vacuum state is -0.08 MPa to -0.1 MPa, and the vacuum state time is 5 min to 10 min;

[0093] 126 parts of the base material were placed in the mixing barrel of a double planetary mixer, and 8 parts of hydrogenated silicone oil and 1 part of 3-phenyl-1-butyn-3-ol were added to the mixing barrel of the double planetary mixer and stirred evenly to prepare component A.

[0094] 20 parts by weight of the base material were put into a mixing barrel of a double planetary mixer, and 20 parts by weight of the platinum-vinylsiloxane complex were added and stirred evenly to prepare component B.

[0095] Component A and component B were packaged in plastic barrels respectively and sealed intactly, wherein the mixing ratio of component A to component B was 17:1, and the viscosity after mixing was 145471 mPa·s.

[0096] If conventional silicone rubber tackifier T907 produced by Wuhan Enric Materials Co., Ltd. is added and the other preparation methods are exactly the same, the viscosity of the prepared adhesive is 282502 mPa·s.

[0097] The measurement is carried out according to the method of "GB / T 2794-2022 Determination of viscosity of adhesives".

[0098] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0099] Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface;

[0100] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0101] The adhesive component A and component B are mixed in a mass ratio of 17:1, stirred evenly, and the adhesive is subjected to a vacuum degassing treatment with a vacuum degree of -0.08 MPa to -0.1 MPa and a vacuum state time of 5 min to 10 min to obtain the desired adhesive;

[0102] Use ethyl acetate to clean the polished area and let it dry at room temperature for 20 minutes to 60 minutes;

[0103] Apply epoxy silane coupling agent to the bonding area of ​​the inner insulation layer head prefabricated part, and apply epoxy silane coupling agent to the bonding area of ​​the inner surface of the metal shell, and let it air-dry at room temperature for 20 minutes to 40 minutes;

[0104] Use a brush to pick up the degassed adhesive and evenly apply it to the bonding area of ​​the inner insulation layer head prefabricated part and the inner surface bonding area of ​​the metal shell. The thickness of the adhesive should be controlled at 0.02mm~0.05mm.

[0105] Fit the inner insulation layer head prefabricated part to the inner surface of the metal shell; install the airbag and airbag tooling;

[0106] Slowly apply pressure using an airbag, maintaining it at 0.4 MPa until excess adhesive overflows. After 10 minutes, transfer the engine casing (including the head preform and airbag) to a heating device. Raise the temperature to 150°C at a rate of 20°C / min, hold for 1 hour, and then cool back to room temperature. This completes the bonding of the inner insulation layer to the metal casing. Example 3

[0107] An adhesive for the inner thermal insulation layer of a solid rocket motor, comprising the following components:

[0108] 90 parts of methylphenyl silicone rubber (viscosity of 50,000 mPa·s), 10 parts of zirconium oxide powder, 40 parts of D233 glass powder, 10 parts of polyborosiloxane (viscosity of 900 mPa·s), 4 parts of hydrogenated silicone oil, 0.3 parts of 3-methyl-1-pentyn-3-ol, 1 part of constant viscosity tackifier, and 10 parts of platinum-vinylsiloxane complex.

[0109] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0110] 90 parts by weight of methylphenyl silicone rubber, 10 parts by weight of zirconium oxide powder, 40 parts by weight of glass powder, and 10 parts by weight of polyborosiloxane are placed in a mixing barrel of a double planetary mixer in that order, and the rubber is subjected to a vacuum degassing treatment to prepare a base material, wherein the vacuum degree of the vacuum state is -0.08 MPa to -0.1 MPa, and the vacuum state time is 5 min to 10 min;

[0111] 126 parts by weight of the base material were placed in the mixing barrel of a double planetary mixer, and 4 parts by weight of hydrogenated silicone oil and 0.3 parts by weight of 3-methyl-1-pentyn-3-ol were added to the mixing barrel of the double planetary mixer, and stirred evenly to prepare component A.

[0112] 10 parts by weight of the base material were put into a mixing barrel of a double planetary mixer, and 10 parts by weight of the platinum-vinylsiloxane complex were added and stirred evenly to prepare component B.

[0113] Component A and component B are packaged in plastic barrels respectively and sealed intactly, wherein the mixing ratio of component A to component B is 20:1, and the viscosity after mixing is 160154 mPa·s.

[0114] If conventional silicone rubber tackifier T907 produced by Wuhan Enric Materials Co., Ltd. is added and the other preparation methods are exactly the same, the viscosity of the prepared adhesive is 312520 mPa·s.

[0115] The measurement is carried out according to the method of "GB / T 2794-2022 Determination of viscosity of adhesives".

[0116] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0117] Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface;

[0118] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0119] The adhesive component A and component B are mixed in a mass ratio of 20:1, stirred evenly, and the adhesive is subjected to a vacuum degassing treatment with a vacuum degree of -0.08 MPa to -0.1 MPa and a vacuum state time of 5 min to 10 min to obtain the desired adhesive;

[0120] Use ethyl acetate to clean the polished area and let it dry at room temperature for 20 minutes to 60 minutes;

[0121] Apply epoxy silane coupling agent to the bonding area of ​​the inner insulation layer head prefabricated part, and apply epoxy silane coupling agent to the bonding area of ​​the inner surface of the metal shell, and let it air-dry at room temperature for 20 minutes to 40 minutes;

[0122] Use a brush to pick up the degassed adhesive and evenly apply it to the bonding area of ​​the inner insulation layer head prefabricated part and the inner surface bonding area of ​​the metal shell. The thickness of the adhesive should be controlled at 0.02mm~0.05mm.

[0123] Fit the inner insulation layer head prefabricated part to the inner surface of the metal shell; install the airbag and airbag tooling;

[0124] Use the airbag to slowly apply pressure, maintaining it at 0.5 MPa. Excess adhesive will overflow. After 10 minutes, transfer the engine housing (including the head preform and airbag) to a heating device. Raise the temperature to 150°C at a rate of 20°C / min, hold for 1 hour, and then cool back to room temperature. This completes the bonding of the inner insulation layer to the metal housing.

[0125] In order to further illustrate the key points of this patent, a comparative case is added for illustration.

[0126] Comparative Example 1

[0127] An adhesive for the inner thermal insulation layer of a solid rocket motor, comprising the following components:

[0128] 150 parts of methyl vinyl phenyl silicone rubber (viscosity 500mPa·s), 30 parts of mica powder, 5 parts of polyborosiloxane (viscosity 600mPa·s), 6 parts of hydrogenated silicone oil, 0.5 parts of 3-phenyl-1-butyn-3-ol, 0.5 parts of constant viscosity tackifier, and 16 parts of platinum-vinylsiloxane complex.

[0129] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0130] 150 parts by weight of methyl vinyl phenyl silicone rubber, 30 parts by weight of mica powder, and 5 parts of polyborosiloxane are placed in a mixing barrel of a double planetary mixer in that order, and the rubber is subjected to a vacuum degassing treatment to prepare a base material, wherein the vacuum degree of the vacuum state is -0.08 MPa to -0.1 MPa, and the vacuum state time is 5 min to 10 min;

[0131] 126 parts by weight of the base material were placed in a mixing barrel of a double planetary mixer, and 6 parts by weight of hydrogenated silicone oil and 0.5 parts by weight of 3-phenyl-1-butyn-3-ol were added to the mixing barrel of the double planetary mixer, and stirred evenly to prepare component A.

[0132] 15 parts by weight of the base material were put into a mixing barrel of a double planetary mixer, and 16 parts by weight of the platinum-vinylsiloxane complex were added and stirred evenly to prepare component B.

[0133] Component A and component B are packaged in plastic barrels respectively and sealed intactly, wherein the mixing ratio of component A to component B is 13:1, and the viscosity after mixing is 110210 mPa·s.

[0134] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0135] Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface;

[0136] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0137] The adhesive component A and component B are mixed in a mass ratio of 13:1, stirred evenly, and the adhesive is subjected to a vacuum degassing treatment with a vacuum degree of -0.08 MPa to -0.1 MPa and a vacuum state time of 5 min to 10 min to obtain the desired adhesive;

[0138] Use ethyl acetate to clean the polished area and let it dry at room temperature for 20 minutes to 60 minutes;

[0139] Apply epoxy silane coupling agent to the bonding area of ​​the inner insulation layer head prefabricated part, and apply epoxy silane coupling agent to the bonding area of ​​the inner surface of the metal shell, and let it air-dry at room temperature for 20 minutes to 40 minutes;

[0140] Use a brush to pick up the degassed adhesive and evenly apply it to the bonding area of ​​the inner insulation layer head prefabricated part and the inner surface bonding area of ​​the metal shell. The thickness of the adhesive should be controlled at 0.02mm~0.05mm.

[0141] Fit the inner insulation layer head prefabricated part to the inner surface of the metal shell; install the airbag and airbag tooling;

[0142] Slowly apply pressure using an airbag, maintaining it at 0.3 MPa until excess adhesive overflows. After 10 minutes, transfer the engine housing (including the head preform and airbag) to a heating device. Raise the temperature to 150°C at a rate of 20°C / min, hold for 1 hour, and then cool back to room temperature. This completes the bonding of the inner insulation layer to the metal housing.

[0143] Comparative Example 2

[0144] An adhesive for the inner thermal insulation layer of a solid rocket motor, comprising the following components:

[0145] 150 parts of methyl vinyl phenyl silicone rubber (viscosity 500mPa·s), 30 parts of mica powder, 20 parts of D233 glass powder, 6 parts of hydrogenated silicone oil, 0.5 parts of 3-phenyl-1-butyn-3-ol, 0.5 parts of constant viscosity tackifier, and 16 parts of platinum-vinylsiloxane complex.

[0146] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0147] 150 parts by weight of methyl vinyl phenyl silicone rubber, 30 parts by weight of mica powder, and 20 parts by weight of glass powder are placed in a mixing barrel of a double planetary mixer in that order, and the rubber is subjected to a vacuum degassing treatment to prepare a base material, wherein the vacuum degree of the vacuum state is -0.08 MPa to -0.1 MPa, and the vacuum state time is 5 min to 10 min;

[0148] 126 parts by weight of the base material were placed in a mixing barrel of a double planetary mixer, and 6 parts by weight of hydrogenated silicone oil and 0.5 parts by weight of 3-phenyl-1-butyn-3-ol were added to the mixing barrel of the double planetary mixer, and stirred evenly to prepare component A.

[0149] 15 parts by weight of the base material were put into a mixing barrel of a double planetary mixer, and 16 parts by weight of the platinum-vinylsiloxane complex were added and stirred evenly to prepare component B.

[0150] Component A and component B were packaged in plastic barrels respectively and sealed intactly, wherein the mixing ratio of component A to component B was 13:1, and the viscosity after mixing was 110251 mPa·s.

[0151] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0152] Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface;

[0153] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0154] The adhesive component A and component B are mixed in a mass ratio of 13:1, stirred evenly, and the adhesive is subjected to a vacuum degassing treatment with a vacuum degree of -0.08 MPa to -0.1 MPa and a vacuum state time of 5 min to 10 min to obtain the desired adhesive;

[0155] Use ethyl acetate to clean the polished area and let it dry at room temperature for 20 minutes to 60 minutes;

[0156] Apply epoxy silane coupling agent to the bonding area of ​​the inner insulation layer head prefabricated part, and apply epoxy silane coupling agent to the bonding area of ​​the inner surface of the metal shell, and let it air-dry at room temperature for 20 minutes to 40 minutes;

[0157] Use a brush to pick up the degassed adhesive and evenly apply it to the bonding area of ​​the inner insulation layer head prefabricated part and the inner surface bonding area of ​​the metal shell. The thickness of the adhesive should be controlled at 0.02mm~0.05mm.

[0158] Fit the inner insulation layer head prefabricated part to the inner surface of the metal shell; install the airbag and airbag tooling;

[0159] Slowly apply pressure using an airbag, maintaining it at 0.3 MPa until excess adhesive overflows. After 10 minutes, transfer the engine housing (including the head preform and airbag) to a heating device. Raise the temperature to 150°C at a rate of 20°C / min, hold for 1 hour, and then cool back to room temperature. This completes the bonding of the inner insulation layer to the metal housing.

[0160] Comparative Example 3

[0161] An adhesive for the inner thermal insulation layer of a solid rocket motor, comprising the following components:

[0162] 150 parts of methyl vinyl phenyl silicone rubber (viscosity 500mPa·s), 30 parts of mica powder, 6 parts of hydrogenated silicone oil, 0.5 parts of 3-phenyl-1-butyn-3-ol, 0.5 parts of constant viscosity tackifier, and 16 parts of platinum-vinylsiloxane complex.

[0163] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0164] 150 parts by weight of methyl vinyl phenyl silicone rubber and 30 parts by weight of mica powder are placed in a mixing barrel of a double planetary mixer in that order, and the rubber is subjected to a vacuum degassing treatment to prepare a base material, wherein the vacuum degree of the vacuum state is -0.08 MPa to -0.1 MPa, and the vacuum state time is 5 min to 10 min;

[0165] 126 parts by weight of the base material were placed in a mixing barrel of a double planetary mixer, and 6 parts by weight of hydrogenated silicone oil and 0.5 parts by weight of 3-phenyl-1-butyn-3-ol were added to the mixing barrel of the double planetary mixer, and stirred evenly to prepare component A.

[0166] 15 parts by weight of the base material were put into a mixing barrel of a double planetary mixer, and 16 parts by weight of the platinum-vinylsiloxane complex were added and stirred evenly to prepare component B.

[0167] Component A and component B are packaged in plastic barrels respectively and sealed intactly, wherein the mixing ratio of component A to component B is 13:1, and the viscosity after mixing is 125410 mPa·s.

[0168] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0169] Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface;

[0170] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0171] The adhesive component A and component B are mixed in a mass ratio of 13:1, stirred evenly, and the adhesive is subjected to a vacuum degassing treatment with a vacuum degree of -0.08 MPa to -0.1 MPa and a vacuum state time of 5 min to 10 min to obtain the desired adhesive;

[0172] Use ethyl acetate to clean the polished area and let it dry at room temperature for 20 minutes to 60 minutes;

[0173] Apply epoxy silane coupling agent to the bonding area of ​​the inner insulation layer head prefabricated part, and apply epoxy silane coupling agent to the bonding area of ​​the inner surface of the metal shell, and let it air-dry at room temperature for 20 minutes to 40 minutes;

[0174] Use a brush to pick up the degassed adhesive and evenly apply it to the bonding area of ​​the inner insulation layer head prefabricated part and the inner surface bonding area of ​​the metal shell. The thickness of the adhesive should be controlled at 0.02mm~0.05mm.

[0175] Fit the inner insulation layer head prefabricated part to the inner surface of the metal shell; install the airbag and airbag tooling;

[0176] Slowly apply pressure using an airbag, maintaining it at 0.3 MPa until excess adhesive overflows. After 10 minutes, transfer the engine housing (including the head preform and airbag) to a heating device. Raise the temperature to 150°C at a rate of 20°C / min, hold for 1 hour, and then cool back to room temperature. This completes the bonding of the inner insulation layer to the metal housing.

[0177] Comparative Example 4

[0178] An adhesive for the inner thermal insulation layer of a solid rocket motor, comprising the following components in parts by mass:

[0179] 150 parts of methyl vinyl silicone rubber (viscosity 500mPa·s), 30 parts of mica powder, 20 parts of D233 glass powder, 5 parts of polyborosiloxane (viscosity 400mPa·s), 6 parts of hydrogenated silicone oil, 0.5 parts of 3-phenyl-1-butyn-3-ol, 0.5 parts of constant viscosity tackifier, and 16 parts of platinum-vinylsiloxane complex.

[0180] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0181] 150 parts of methyl vinyl silicone rubber, 30 parts of mica powder, 20 parts of glass powder, and 5 parts of polyborosiloxane are placed in a mixing barrel of a double planetary mixer in that order, and the rubber is subjected to a vacuum degassing treatment to prepare a base material, wherein the vacuum degree of the vacuum state is -0.08 MPa to -0.1 MPa, and the vacuum state time is 5 min to 10 min;

[0182] 126 parts of the base material were placed in the mixing barrel of a double planetary mixer, and 6 parts of hydrogenated silicone oil and 0.5 parts of 3-phenyl-1-butyn-3-ol were added to the mixing barrel of the double planetary mixer and stirred evenly to prepare component A.

[0183] 15 parts of the base material were put into a mixing barrel of a double planetary mixer, and 16 parts of the platinum-vinylsiloxane complex were added and stirred evenly to prepare component B.

[0184] Component A and component B are packaged in plastic barrels respectively and sealed intactly, wherein the mixing mass ratio of component A to component B is 13:1, and the viscosity after mixing is 124102 mPa·s.

[0185] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0186] Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface;

[0187] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0188] The adhesive component A and component B are mixed in a mass ratio of 13:1, stirred evenly, and the adhesive is subjected to a vacuum degassing treatment with a vacuum degree of -0.08 MPa to -0.1 MPa and a vacuum state time of 5 min to 10 min to obtain the desired adhesive;

[0189] Use ethyl acetate to clean the polished area and let it dry at room temperature for 20 minutes to 60 minutes;

[0190] Apply epoxy silane coupling agent to the bonding area of ​​the inner insulation layer head prefabricated part, and apply epoxy silane coupling agent to the bonding area of ​​the inner surface of the metal shell, and let it air-dry at room temperature for 20 minutes to 40 minutes;

[0191] Use a brush to pick up the degassed adhesive and evenly apply it to the bonding area of ​​the inner insulation layer head prefabricated part and the inner surface bonding area of ​​the metal shell. The thickness of the adhesive should be controlled at 0.02mm~0.05mm.

[0192] Fit the inner insulation layer head prefabricated part to the inner surface of the metal shell; install the airbag and airbag tooling;

[0193] Slowly apply pressure using an airbag, maintaining it at 0.3 MPa until excess adhesive overflows. After 10 minutes, transfer the engine housing (including the head preform and airbag) to a heating device. Raise the temperature to 150°C at a rate of 20°C / min, hold for 1 hour, and then cool back to room temperature. This completes the bonding of the inner insulation layer to the metal housing.

[0194] Comparative Example 5

[0195] An adhesive for the inner thermal insulation layer of a solid rocket motor, comprising the following components in parts by mass:

[0196] 150 parts of methyl vinyl silicone rubber (viscosity 500mPa·s), 30 parts of mica powder, 20 parts of D233 glass powder, 5 parts of polyborosiloxane (viscosity 6000mPa·s), 6 parts of hydrogenated silicone oil, 0.5 parts of 3-phenyl-1-butyn-3-ol, 0.5 parts of constant viscosity tackifier, and 16 parts of platinum-vinylsiloxane complex.

[0197] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0198] 150 parts of methyl vinyl silicone rubber, 30 parts of mica powder, 20 parts of glass powder, and 5 parts of polyborosiloxane are placed in a mixing barrel of a double planetary mixer in that order, and the rubber is subjected to a vacuum degassing treatment to prepare a base material, wherein the vacuum degree of the vacuum state is -0.08 MPa to -0.1 MPa, and the vacuum state time is 5 min to 10 min;

[0199] 126 parts of the base material were placed in the mixing barrel of a double planetary mixer, and 6 parts of hydrogenated silicone oil and 0.5 parts of 3-phenyl-1-butyn-3-ol were added to the mixing barrel of the double planetary mixer and stirred evenly to prepare component A.

[0200] 15 parts of the base material were put into a mixing barrel of a double planetary mixer, and 16 parts of the platinum-vinylsiloxane complex were added and stirred evenly to prepare component B.

[0201] Component A and component B are packaged in plastic barrels respectively and sealed intactly, wherein the mixing mass ratio of component A to component B is 13:1, and the viscosity after mixing is 124102 mPa·s.

[0202] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0203] Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface;

[0204] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0205] The adhesive component A and component B are mixed in a mass ratio of 13:1, stirred evenly, and the adhesive is subjected to a vacuum degassing treatment with a vacuum degree of -0.08 MPa to -0.1 MPa and a vacuum state time of 5 min to 10 min to obtain the desired adhesive;

[0206] Use ethyl acetate to clean the polished area and let it dry at room temperature for 20 minutes to 60 minutes;

[0207] Apply epoxy silane coupling agent to the bonding area of ​​the inner insulation layer head prefabricated part, and apply epoxy silane coupling agent to the bonding area of ​​the inner surface of the metal shell, and let it air-dry at room temperature for 20 minutes to 40 minutes;

[0208] Use a brush to pick up the degassed adhesive and evenly apply it to the bonding area of ​​the inner insulation layer head prefabricated part and the inner surface bonding area of ​​the metal shell. The thickness of the adhesive should be controlled at 0.02mm~0.05mm.

[0209] Fit the inner insulation layer head prefabricated part to the inner surface of the metal shell; install the airbag and airbag tooling;

[0210] Slowly apply pressure using an airbag, maintaining it at 0.3 MPa until excess adhesive overflows. After 10 minutes, transfer the engine housing (including the head preform and airbag) to a heating device. Raise the temperature to 150°C at a rate of 20°C / min, hold for 1 hour, and then cool back to room temperature. This completes the bonding of the inner insulation layer to the metal housing.

[0211] Comparative Example 6

[0212] An adhesive for the inner thermal insulation layer of a solid rocket motor, comprising the following components in parts by mass:

[0213] 150 parts of methyl vinyl silicone rubber (viscosity 500mPa·s), 30 parts of mica powder, 20 parts of D233 glass powder, 5 parts of polyborosiloxane (viscosity 600mPa·s), 6 parts of hydrogenated silicone oil, 0.5 parts of 3-phenyl-1-butyn-3-ol, 0.5 parts of constant viscosity tackifier, and 16 parts of platinum-vinylsiloxane complex.

[0214] A method for preparing an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0215] 150 parts of methyl vinyl silicone rubber, 30 parts of mica powder, 20 parts of glass powder, and 5 parts of polyborosiloxane are placed in a mixing barrel of a double planetary mixer in that order, and the rubber is subjected to a vacuum degassing treatment to prepare a base material, wherein the vacuum degree of the vacuum state is -0.08 MPa to -0.1 MPa, and the vacuum state time is 5 min to 10 min;

[0216] 126 parts of the base material were placed in the mixing barrel of a double planetary mixer, and 6 parts of hydrogenated silicone oil and 0.5 parts of 3-phenyl-1-butyn-3-ol were added to the mixing barrel of the double planetary mixer and stirred evenly to prepare component A.

[0217] 15 parts of the base material were put into a mixing barrel of a double planetary mixer, and 16 parts of the platinum-vinylsiloxane complex were added and stirred evenly to prepare component B.

[0218] Component A and component B are packaged in plastic barrels respectively and sealed intactly, wherein the mixing mass ratio of component A to component B is 13:1, and the viscosity after mixing is 130210 mPa·s.

[0219] An application of an adhesive for a thermal insulation layer in a solid rocket motor comprises the following steps:

[0220] Use 40-80 mesh sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface;

[0221] Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface;

[0222] The adhesive component A and component B are mixed in a mass ratio of 13:1, stirred evenly, and the adhesive is subjected to a vacuum degassing treatment with a vacuum degree of -0.08 MPa to -0.1 MPa and a vacuum state time of 5 min to 10 min to obtain the desired adhesive;

[0223] Use ethyl acetate to clean the polished area and let it dry at room temperature for 20 minutes to 60 minutes;

[0224] Apply epoxy silane coupling agent to the bonding area of ​​the inner insulation layer head prefabricated part, and apply epoxy silane coupling agent to the bonding area of ​​the inner surface of the metal shell, and let it air-dry at room temperature for 20 minutes to 40 minutes;

[0225] Use a brush to pick up the degassed adhesive and evenly apply it to the bonding area of ​​the inner insulation layer head prefabricated part and the inner surface bonding area of ​​the metal shell. The thickness of the adhesive should be controlled at 0.02mm~0.05mm.

[0226] Place the engine housing in a vacuum chamber, close the door, and use a vacuum pump to evacuate the chamber to a vacuum degree of less than -0.096 MPa. After reaching the vacuum degree, maintain the pressure for 1-3 hours, then slowly introduce air at a speed of 100 L / min.

[0227] Place the engine housing in a heating device, pressurize the rubber airbag to a pressure of 0.6-0.8 MPa, and heat to 80-100°C for 1-3 hours. Then cool to room temperature and pressure, and remove the engine housing from the heating device.

[0228] Flaw detection steps: Use a digital ultrasonic flaw detector to inspect all insulation layer bonding interfaces to check for any debonding.

[0229] Curing steps: Place the rubber airbag into the engine casing, then place the engine casing in a heating device, pressurize the rubber airbag to 1.1MPa±0.1MPa, heat it to 110℃±5℃ and keep it warm for 2 hours, then heat it to 165℃±5℃ at a rate of 15℃ / h and keep it warm for 1 hour, then cool it to 100℃±5℃ at a rate of 15℃ / h, and finally cool it to room temperature, take out the engine casing, and complete the molding of the insulation layer inside the engine casing.

[0230] The adhesives prepared in Examples 1-3 and Comparative Examples 1-6, and the bonded inner insulation layer head preforms and metal shells were subjected to performance tests according to the following test standards: shear performance was QJ2038.2, tearing performance was QJ2038.1A, and oxyacetylene wire ablation rate was GJB 323A.

[0231] We can conclude that:

[0232] The adhesive for the solid rocket motor's inner insulation layer provides excellent ablation resistance, with an oxy-acetylene line ablation rate of less than 0.07 mm / s. The adhesive exhibits excellent high-temperature bonding performance, maintaining good adhesion at the interface between the silicone rubber inner insulation layer and the metal (D406A steel) casing at 350°C. Performance testing of the adhesive after bonding the inner insulation layer to the metal casing at 350°C (thermocouple) is shown in the figure below. Figure 1 Schematic diagram of the oxygen-acetylene wire ablation principle. The red arrow indicates the direction of the ablation flame ablating the bonded test piece. Figure 2 This is a schematic diagram of the bonding performance test results of the bonding test pieces after ablation. The black circles from left to right are named bonding test pieces No. 1, No. 2, No. 3 and No. 4, respectively. Bonding test pieces No. 1 and No. 2 are the adhesives without glass powder and polyborosiloxane added in Comparative Examples 1 and 2, respectively. The peeling interfaces of bonding test pieces No. 1 and No. 2 are destroyed, leaving only metal (D406A steel), indicating that the adhesives prepared in Comparative Examples 1 and 2 have poor high-temperature bonding performance. Bonding test pieces No. 3 and No. 4 are test pieces bonded with the adhesive of the present application in Examples 1 and 2. After ablation, the insulation layer of the lower half of test pieces No. 3 and No. 4 was peeled off, and what remained was the adhesive + insulation layer, indicating that their bonding performance was good and manual peeling could not completely peel them off; the upper half was not peeled off, and what remained was the adhesive + insulation layer (the white part in the middle was the insulation layer); after the lower half of the bonding test pieces No. 3 and No. 4 was peeled off, the inner insulation layer body and the adhesive were destroyed, indicating that the metal shell and the adhesive, and the adhesive and the inner insulation layer were well bonded at 350°C.

[0233] Specifically:

[0234] The shear strength of the bonded inner insulation layer head preform and the metal shell in Example 1 was 2.02 MPa, and the tear strength was 2.03 MPa. The bonding quality between the inner insulation layer head preform and the metal shell was good. Under the test of oxy-acetylene wire ablation, no interfacial peeling or blistering occurred. The oxy-acetylene wire ablation rate of the adhesive was 0.05 mm / s. The shell / adhesive and adhesive / inner insulation layer both bonded well at 350°C. After peeling, the adhesive and the inner insulation body were destroyed. The metal shell and the adhesive, as well as the adhesive and the inner insulation layer, both bonded well at 350°C.

[0235] In Example 2, the shear strength of the bonded inner insulation layer head preform and the metal shell was 2.16 MPa, and the tear strength was 2.23 MPa. The bonding quality between the inner insulation layer head preform and the metal shell was good. Under the test of oxy-acetylene wire ablation, no interfacial peeling or blistering occurred. The oxy-acetylene wire ablation rate of the adhesive was 0.06 mm / s. The shell / adhesive and adhesive / inner insulation layer both bonded well at 350°C. After peeling, the adhesive and the inner insulation body were destroyed. The metal shell and the adhesive, as well as the adhesive and the inner insulation layer, bonded well at 350°C.

[0236] In Example 3, the shear strength of the bonded inner insulation layer head preform and the metal shell was 2.01 MPa, and the tear strength was 2.00 MPa. The bonding quality between the inner insulation layer head preform and the metal shell was good. Under the test of oxy-acetylene wire ablation, no interfacial peeling or blistering occurred. The oxy-acetylene wire ablation rate of the adhesive was 0.05 mm / s. The shell / adhesive and adhesive / inner insulation layer were well bonded at 350°C. After peeling, the adhesive and the inner insulation body were damaged. The metal shell and the adhesive, and the adhesive and the inner insulation layer were well bonded at 350°C.

[0237] Compared to Example 1, in which no glass frit was added, the bonded inner insulation layer head preform and metal shell exhibited a shear strength of 2.01 MPa and a pull-off strength of 2.00 MPa, indicating good interlayer bonding quality. Oxy-acetylene ablation tests revealed no interfacial delamination or blistering. The adhesive exhibited an oxy-acetylene ablation rate of 0.08 mm / s. Bonding between the shell and adhesive, and between the adhesive and inner insulation layer, was poor at 350°C, with delamination indicating failure at the interface between the adhesive and metal shell.

[0238] In Comparative Example 2, where polyborosiloxane was not added, the bonded inner insulation layer head preform and metal shell exhibited a shear strength of 1.85 MPa and a pull-off strength of 1.98 MPa, indicating excellent interlayer bonding quality. Oxyacetylene ablation demonstrated no interfacial delamination or blistering. The adhesive exhibited an oxyacetylene ablation rate of 0.08 mm / s. Bonding performance was poor at 350°C for both the shell / adhesive and adhesive / inner insulation layer bonds, with delamination indicating failure at the interface between the adhesive and metal shell.

[0239] In Comparative Example 3, neither glass frit nor polyborosiloxane was added. The bonded inner insulation layer head preform and metal shell exhibited a shear strength of 1.41 MPa and a pull-off strength of 1.32 MPa, indicating fair interlayer bonding quality. Oxyacetylene ablation testing revealed no interfacial delamination or blistering. The adhesive exhibited an oxyacetylene ablation rate of 0.11 mm / s. Bonding performance was poor at 350°C for both the shell / adhesive and adhesive / inner insulation layers, with delamination indicating failure at the interface between the adhesive and inner insulation layer.

[0240] In Comparative Example 4, the polyborosiloxane had a viscosity of 400 mPa·s. The bonded inner insulation layer head preform and metal shell exhibited a shear strength of 1.98 MPa and a pull-off strength of 1.95 MPa, indicating excellent interlayer bonding. Oxyacetylene ablation showed no interfacial delamination or blistering. The adhesive exhibited an oxyacetylene ablation rate of 0.13 mm / s. Bonding performance was poor at 350°C for both the shell / adhesive and adhesive / inner insulation layers, with delamination indicating failure at the interface between the adhesive and the inner insulation layer.

[0241] In Comparative Example 5, the polyborosiloxane had a viscosity of 6000 mPa·s. The bonded inner insulation layer head preform and metal shell exhibited a shear strength of 1.95 MPa and a pull-off strength of 1.92 MPa, indicating excellent interlayer bonding. Oxyacetylene ablation showed no interfacial delamination or blistering. The adhesive exhibited an oxyacetylene ablation rate of 0.12 mm / s. Bonding performance was poor at 350°C for both the shell / adhesive and adhesive / inner insulation layers, with delamination occurring at the interface between the adhesive and the inner insulation layer.

[0242] In Comparative Example 6, the shear strength of the bonded inner insulation layer head preform and the metal shell was 2.00 MPa, and the tear strength was 2.01 MPa. The bonding quality between the inner insulation layer head preform and the metal shell was good. Under the test of oxy-acetylene wire ablation, no interface peeling or blistering occurred. The oxy-acetylene wire ablation rate of the adhesive was 0.05 mm / s. The shell / adhesive and adhesive / inner insulation layer were well bonded at 350°C. After peeling, the inner insulation layer body and the adhesive were damaged. However, the process is more complicated and takes longer than the process of the present invention.

[0243] In summary, the present application has good high-temperature bonding performance through the synergistic effect of polyborosiloxane, ablation-resistant filler and glass powder. The adhesive has excellent ablation resistance, and the oxygen-acetylene line ablation rate is ≤0.07mm / s. Under a 350°C environment, the inner insulation layer of the silicone rubber and the metal shell interface are still well bonded. In addition, the adhesive coating process is simple, only one-time coating is required, and the next step can be carried out after coating; the cycle is short, only 10 minutes of cold pressing and 1 hour of hot pressing are required, and the 1h to 3h hot pre-pressing step in the prior art is not required. The pressure is smaller than the conventional 0.6MPa~0.8MPa, and only 0.3MPa~0.5MPa is required.

[0244] The above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, it may also include many other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An adhesive for the inner thermal insulation layer of a solid rocket engine, characterized in that: Including the following raw materials in parts by mass: 90~180 parts of silicone rubber 10~30 parts of ablation-resistant filler 20~40 parts glass powder 5-10 parts of polyborosiloxane 4~8 parts of cross-linking agent 0.3~1 part of inhibitor 0.5~1 part of constant viscosity thickener 10-20 parts of catalyst; The constant viscosity tackifier is synthesized by hydrosilylation reaction using phenyl tris(dimethylsiloxane) silane and cardanol polyoxyethylene ether as raw materials in a mass ratio of (2.5-3.5):1; The constant viscosity tackifier synthesis method comprises the following steps: Phenyltris(dimethylsiloxy)silane was added into a reactor equipped with a stirrer, a thermometer and a condensation reflux device; Add nitrogen and raise the temperature to 80-90°C; Add platinum catalyst and keep warm for a while, then slowly add cardanol polyoxyethylene ether dropwise; After the addition is complete, start timing and allow the reaction to proceed for 2.5-3.5 hours; The platinum catalyst includes a platinum-vinylsiloxane complex.

2. The adhesive for the inner thermal insulation layer of a solid rocket motor according to claim 1, characterized in that: The silicone rubber includes one or more of methyl vinyl silicone rubber and methyl vinyl phenyl silicone rubber; the viscosity of the silicone rubber is 500-50000 mPa·s.

3. The adhesive for the inner thermal insulation layer of a solid rocket motor according to claim 1, characterized in that: The ablation-resistant filler includes one or more of mica powder, diatomaceous earth powder, kaolin, silica lime powder, modified silicon carbide nanopowder, zirconium oxide powder, magnesium carbonate, and aluminum oxide powder; and the particle size of the ablation-resistant filler is less than 600 meshes.

4. The adhesive for the inner thermal insulation layer of a solid rocket motor according to claim 1, characterized in that: The glass powder is D233.

5. The adhesive for the inner thermal insulation layer of a solid rocket motor according to claim 1, characterized in that: The viscosity of the polyborosiloxane is 500 mPa·s to 900 mPa·s.

6. The adhesive for the inner thermal insulation layer of a solid rocket motor according to claim 1, characterized in that: The crosslinking agent includes hydrogen-containing silicone oil; the inhibitor includes one or more of 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, and 3-phenyl-1-butyn-3-ol.

7. The method for preparing the adhesive for the inner thermal insulation layer of a solid rocket motor according to any one of claims 1 to 6, characterized in that: The following steps are involved: Silicone rubber, ablation-resistant filler, glass powder, and polyborosiloxane are placed in a mixing barrel of a double planetary mixer according to a certain proportion, and vacuum degassing treatment is performed to prepare a base material; Take a certain amount of base material and put it into the mixing barrel of the double planetary mixer. Add the crosslinking agent, inhibitor and constant viscosity thickener into the mixing barrel of the double planetary mixer according to the proportion and stir evenly to prepare component A. Take a certain amount of base material and put it into the mixing barrel of a double planetary mixer, add the catalyst according to the proportion, and stir evenly to obtain component B; The component A and the component B are mixed uniformly in a mass ratio of (13-20):1 to obtain an adhesive for the thermal insulation layer of a solid rocket motor; Wherein, the mass ratio of the base material in the component A and the component B is 126: (10~20); The vacuum degree of the vacuum degassing treatment is -0.08 to -0.1 MPa, and the mixing time of the degassing treatment is 0.5 to 2 hours under the vacuum state.

8. An application of an adhesive for the inner thermal insulation layer of a solid rocket engine, wherein the adhesive is the adhesive for the inner thermal insulation layer of a solid rocket engine according to any one of claims 1 to 6, characterized in that: The following steps are involved: Use sandpaper to grind the bonding area of ​​the inner insulation layer head prefabricated part until it is rough and has no reflective surface. Then use ethyl acetate to clean the grinded area and let it air-dry at room temperature. Use diamond abrasive to sandblast the bonding area of ​​the inner surface of the metal shell until it is rough and has no reflective surface; Applying epoxy silane coupling agent to the treated bonding area of ​​the inner insulation layer head preform and the bonding area of ​​the inner profile of the metal shell, and leaving them to air at room temperature; Use a brush to pick up the adhesive and evenly apply the adhesive to the bonding area of ​​the inner insulation layer head preform and the bonding area of ​​the inner surface of the metal shell after the epoxy silane coupling agent is applied; Laminating the inner insulation layer head prefabricated part coated with the adhesive to the inner surface of the metal shell, and installing the airbag and airbag tooling; Use the airbag to slowly pressurize to a certain pressure, and the excess adhesive overflows. Then the airbag and the bonded inner insulation layer head preform and the metal shell are transported to the heating device together, heated and cooled to complete the bonding of the inner insulation layer and the metal shell.

9. The use of the adhesive for the inner thermal insulation layer of a solid rocket motor according to claim 8, characterized in that: The coating thickness of the adhesive is 0.02mm~0.05mm; when the airbag is pressurized, the required maintaining pressure is 0.3MPa~0.5MPa, the pressurization time is 5min-15min, and after heating treatment, the pressurization time is 0.5h-1.5h.

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