Method for bonding ethylene propylene diene terpolymer to metal inner wall

Abstract

The application discloses a bonding method for three-element ethylene-propylene adiabatic and metal inner wall in the technical field of aerospace winding engine combustion chamber, and comprises the following steps: S1, tool preparation, the tool comprises a mold for laying three-element ethylene-propylene adiabatic rubber; S2, carrying out layering operation on the three-element ethylene-propylene adiabatic rubber on the laying surface of the mold. By compounding fumed silica and powdered foaming glue in the bonding resin composition, the fumed silica is used to improve the resin viscosity to avoid resin migration in the curing process, and the expansion pressure generated by the foaming reaction of the powdered foaming glue during curing is used to form bidirectional force in cooperation with the constraint pressure of the winding layer, so that the bonding strength of the three-element ethylene-propylene adiabatic and the metal inner wall is significantly improved, and the interface debonding problem is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of aerospace winding engine combustion chamber technology, and particularly to a method for bonding EPDM insulation to a metal inner wall. Background Technology

[0002] In the field of aerospace engines, the combustion chamber, as a core component, operates in an extremely harsh environment, needing to withstand high-temperature combustion gas scouring, high-pressure loads, and frequent temperature cycles. Ethylene propylene diene monomer (EPDM) insulation material, due to its excellent high-temperature resistance, aging resistance, and thermal insulation properties, is often used to protect the metal inner walls of the combustion chamber. The reliable bonding between EPDM insulation material and the metal inner wall directly determines the structural integrity, thermal insulation effect, and service life of the combustion chamber, making it a crucial factor in ensuring the stable and safe operation of the engine.

[0003] In existing technologies, the process of bonding EPDM insulation materials to metal-related structures typically uses a winding resin as the core adhesive medium. This involves steps such as layering the EPDM insulation material, applying the adhesive medium, winding the resin, and curing to achieve the connection between the insulation layer and the relevant metal inner wall structure. This type of process has been applied to some extent in the manufacturing of aerospace engine combustion chambers. Its core idea is to achieve interfacial bonding between the two materials through the curing reaction of the adhesive medium.

[0004] However, existing processes still have certain problems in practical applications: On the one hand, the adhesive medium is easily affected by the mechanical action of the process environment during the curing process, resulting in uneven distribution of the adhesive medium at the interface between the EPDM insulation material and the corresponding structure, with some areas showing a lack or thinning of the adhesive medium; on the other hand, this migration and uneven distribution of the adhesive medium directly causes the bonding strength between the two to fail to meet the requirements of long-term engine service. Under complex working conditions of high temperature and high pressure, gaps or even debonding are easily generated at the interface, which not only reduces the heat insulation effect but may also lead to structural failure risks, seriously affecting the operational reliability and service life of aerospace engines. Therefore, we urgently need a bonding method between EPDM insulation and the metal inner wall to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for bonding EPDM insulation to a metal inner wall. By using a bonding system of compounded fumed silica and powdered foam adhesive, and optimizing the layup, winding, and multi-stage curing processes, this method avoids resin migration, enhances interfacial pressure, significantly improves the bonding strength between EPDM insulation and the metal inner wall, eliminates interfacial debonding, and ensures the reliability of aerospace engines during service.

[0006] The objective of this invention is achieved by including the following steps:

[0007] S1: Tooling preparation, the tooling including a mold for laying EPDM heat insulation rubber;

[0008] S2: Perform a layup operation on the EPDM heat insulation rubber on the laying surface of the mold;

[0009] S3: Prepare an adhesive resin composition comprising a base material, a tackifying component and a foaming component, and apply the adhesive resin composition to the surface of the EPDM heat-insulating rubber after the layup operation described in S2.

[0010] S4: Wrapping operation of EPDM insulation rubber coated with adhesive resin composition;

[0011] S5: Curing treatment is performed on the product after the winding operation described in S4.

[0012] Optionally, in the adhesive resin composition, the base material is a winding resin, the tackifying component is fumed silica, the foaming component is powdered foam, and the components are mixed in proportions suitable for adhesive properties.

[0013] Optionally, in S2, the layup operation adopts a covering overlap bonding, and the adjacent EPDM insulation rubber sheets are selected according to their thickness to select the corresponding overlap form, and the overlap width is adapted to the interlayer bonding requirements.

[0014] Optionally, in S2, at least one pre-vacuuming operation is performed during the layup operation, and the vacuum level and duration of the pre-vacuuming are adapted to the layup degassing and shape preservation requirements.

[0015] Optionally, in S3, the adhesive resin composition is prepared by mixing the components and then stirring in stages, with the stirring parameters and intervals set to meet the requirements for uniform mixing of the components.

[0016] Optionally, in S3, the adhesive resin composition is applied to uniformly cover the surface of the EPDM heat-insulating rubber, with the amount of application adapted to the target adhesive strength requirement.

[0017] Optionally, in S4, the winding operation includes longitudinal winding and circumferential winding, and the winding results in a shell structure adapted to the usage scenario.

[0018] Optionally, in S5, the curing process is a multi-stage heating and heat preservation process, which involves heating to the common curing temperature of the base material and the foaming component, heat preservation for a preset time, and then naturally cooling to a temperature suitable for subsequent processing.

[0019] Optionally, in S1, the tooling preparation includes cleaning the mold laying surface. The mold used for the first time needs to be degreased. When the cleaned mold laying surface is not used for the time being, anti-contamination covering measures are taken.

[0020] Optionally, in S2, the amount of EPDM insulation rubber overflow is controlled to match the molding requirements during the layup operation, and air rolling measures are taken during the layup process to ensure a smooth surface. When laying the same layer or multiple layers, the overlapping edges are staggered.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. This invention combines fumed silica and powdered foaming adhesive in an adhesive resin composition. The fumed silica increases the resin viscosity to prevent resin migration during curing, while the foaming reaction of the powdered foaming adhesive during curing generates expansion pressure. Combined with the constraint pressure of the winding layer, this forms a bidirectional force, significantly improving the adhesion strength between EPDM insulation and the metal inner wall, effectively solving the problem of interface debonding.

[0023] 2. This invention optimizes the detailed design of the layup operation, including a covering overlap form adapted to the rubber thickness, layer pre-vacuuming, air rolling, and staggered overlap edges, to ensure that the insulation layer structure is dense, the surface is flat and free of impurities, thereby improving the contact conditions of the bonding interface from the basic level and enhancing the stability of the interlayer bonding.

[0024] 3. This invention, through a multi-stage heating and heat preservation curing process combined with longitudinal-circular combined winding operation, ensures that the winding resin and foam adhesive fully react and cure completely, while reducing internal stress generation through slow heating and natural cooling, thus balancing adhesive strength and product structural integrity and avoiding performance loss due to improper process.

[0025] 4. This invention, through targeted design of each link such as tooling preparation, material configuration, and process operation, such as differentiated mold treatment, segmented mixing of adhesive resin, and precise control of coating amount, ensures bonding effect while taking into account the operability of the process and material compatibility. It is suitable for the production needs of complex working conditions such as aerospace engine combustion chambers, and improves the batch stability and service reliability of products. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 This is a flowchart provided by the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1 As shown in the figure, an embodiment of the present invention provides a method for bonding EPDM insulation to a metal inner wall, comprising the following steps:

[0030] S1: Tooling preparation, which includes molds for laying EPDM insulation rubber.

[0031] In S1, tooling preparation includes cleaning the mold laying surface. Molds used for the first time must be degreased. When the cleaned mold laying surface is not in use, anti-contamination covering measures should be taken.

[0032] Here, the cleaning process involves wiping the mold-layout surface with ethyl acetate using medical degreased gauze, repeating the wiping at least three times until no dust or blackening is visible when wiped with clean medical degreased gauze. Simultaneously, the mold-layout surface must be inspected for damage such as bumps and scratches, and for any peeling or detachment of the Teflon coating. Only after passing quality inspection and process confirmation can the mold-layout surface be used. This operation thoroughly removes oil, dust, and other impurities from the mold-layout surface, preventing impurities from affecting the adhesion between the EPDM insulation rubber and the mold, as well as subsequent bonding effects. Inspecting the mold for damage and the coating prevents unevenness of the layup surface due to mold defects, ensuring the reliability of the process foundation.

[0033] Furthermore, for molds put into production for the first time, the degreasing treatment adopts the oven drying method, with the drying temperature controlled at 180±5℃ and the drying time being 3 hours. Molds that are not used for the first time do not need this degreasing step. Targeted degreasing treatment can thoroughly remove industrial oil stains from the surface of new molds, preventing oil stains from penetrating into the heat insulation rubber layer and affecting the bonding performance. At the same time, the treatment methods for new molds and old molds are distinguished, which not only ensures the process effect but also simplifies the operation process.

[0034] Furthermore, after the mold is transported to the insulation layup room, if the layup operation cannot be carried out immediately, a non-porous release membrane must be used to completely cover the mold layup surface. The non-porous release membrane can effectively block external dust, impurities and moisture from contaminating the mold layup surface, ensuring that the mold is always in a clean state and providing a stable process environment for subsequent layup operations.

[0035] S2: Perform a layup operation on the EPDM insulation rubber on the mold's laying surface.

[0036] In S2, the layup operation adopts a covering overlap bonding. The overlap form of adjacent EPDM insulation rubber sheets is selected according to their thickness, and the overlap width is adapted to the interlayer bonding requirements.

[0037] Here, the overlap width of adjacent EPDM insulation rubber sheets is set to 3mm-5mm. Butt joints are strictly prohibited. Insulation rubber sheets with a thickness ≤2mm can be directly overlapped, while those with a thickness ≥2mm should be overlapped with a beveled cut in the direction of airflow. Overlapping can significantly increase the interlayer contact area compared to butt joints. The 3mm-5mm overlap width and the overlap form suitable for the thickness can effectively avoid gaps between layers and improve the tightness of interlayer adhesion. The beveled cut design in the direction of airflow can also reduce the impact of airflow on the overlap and enhance structural stability.

[0038] Furthermore, when laying the same layer of thermal insulation rubber sheet, the circumferential overlapping edges should be staggered to avoid the overlapping edges being on the same straight line. Staggering the overlapping edges of the same layer can prevent local stress concentration, avoid structural weak areas caused by the alignment of overlapping edges, and improve the stress uniformity of a single layer.

[0039] Furthermore, when laying two or more layers of insulating rubber sheets, the overlapping edges between each layer must also be staggered. The staggered overlapping edge design of multiple layers can form an interlocking structure, further dispersing stress, improving the integrity and peel resistance of the entire layup structure, and providing a solid foundation for subsequent bonding.

[0040] In S2, at least one pre-vacuuming operation is performed during the layup process, and the vacuum level and duration of the pre-vacuuming are adapted to the layup degassing and shape preservation requirements.

[0041] Here, after the first layer of insulation rubber sheet is laid, a pre-vacuuming operation is performed. After that, a pre-vacuuming operation is performed every three layers. Before each pre-vacuuming, it is necessary to check whether there are impurities in the insulation sheet. If there are impurities, the sheet containing the impurities must be removed and a clean sheet must be added before pre-vacuuming. Layered pre-vacuuming can remove the air mixed in during the laying process in time, avoiding the formation of air bubbles that affect the bonding effect. The impurity inspection and treatment before pre-vacuuming can ensure the cleanliness of the laying and further improve the bonding reliability.

[0042] Furthermore, the pre-vacuuming time is no less than 15 minutes each time, and the timing starts after the vacuum degree in the vacuum bag reaches ≤-0.085MPa. Sufficient pre-vacuuming time and stable vacuum degree can ensure that the air in the layer is fully discharged, and at the same time, make the heat insulation rubber sheet tightly bonded to the mold and the interlayer, avoiding structural deformation caused by poor bonding.

[0043] Furthermore, the start and end times of each pre-vacuuming process must be recorded in detail. Complete time records facilitate the traceability of the process, timely detection and adjustment of pre-vacuuming parameter deviations, and ensure the consistency of the process for each batch of products.

[0044] In S2, the amount of EPDM insulation rubber overflow is controlled during the layup operation to meet the molding requirements. Air rolling measures are taken during the layup process to ensure a smooth surface. When laying the same layer or multiple layers, the overlapping edges are staggered.

[0045] Here, when laying the insulating rubber sheet, air-rolling measures must be taken to ensure that the surface is flat after laying, without obvious protrusions, and that the transition at the point where the thickness of the rubber sheet changes is smooth. The air-rolling operation can remove air between the rubber sheet and the mold and between the rubber sheet, avoiding surface protrusions and sudden thickness changes, ensuring the flatness of the laid surface, and providing a uniform working surface for subsequent bonding resin coating and wrapping operations.

[0046] Furthermore, during the layup process, the amount of EPDM insulation rubber overflow is controlled within the range of 5%-10%. A reasonable amount of overflow can fill the tiny gaps between the layers, while avoiding excessive overflow that would lead to material waste and subsequent cleaning difficulties, thus ensuring molding accuracy.

[0047] Furthermore, the sheet material must be cleaned before layup to ensure that no sheet material is missing and to check the quality of the sheet material. The cleaning and quality inspection of the sheet material can prevent the integrity of the layup structure from being affected by the missing or deteriorated sheet material, thus ensuring the process effect from the source.

[0048] S3: Prepare an adhesive resin composition comprising a base material, a tackifying component and a foaming component, and apply the adhesive resin composition to the surface of the EPDM heat-insulating rubber after the S2 layup operation.

[0049] In the adhesive resin composition, the base material is a winding resin, the tackifying component is fumed silica, and the foaming component is powdered foam adhesive. The components are mixed in proportions suitable for the adhesive properties.

[0050] Here, the mass of fumed silica accounts for 10% of the mass of the winding resin, and the mass of powdered foam accounts for 25% of the mass of the winding resin. LWP powdered foam is selected. The 10% proportion of fumed silica can effectively increase the viscosity of the winding resin and prevent resin migration during the curing process. The 25% proportion of LWP powdered foam has good compatibility with the winding resin, and its curing system is consistent with the winding resin, so it can participate in the curing reaction simultaneously.

[0051] Furthermore, the addition of fumed silica can improve the rheological properties of the winding resin, preventing the resin from migrating outward due to centrifugal force and other effects during subsequent curing. After the resin viscosity is increased, its anti-migration ability is enhanced, which can ensure that the bonding resin is evenly distributed on the surface of the heat insulation rubber and avoid weak bonding caused by local resin deficiency.

[0052] Furthermore, LWP powdered foam undergoes a foaming reaction during the curing process, which increases the bonding pressure between the wrapping layer and the insulation rubber layer. Combined with the pressure exerted by the wrapping layer on the insulation layer, this creates a bidirectional pressure effect. This bidirectional pressure promotes the bonding resin to fully wet the surface of the insulation rubber, increasing interfacial bonding force and significantly improving the bonding strength.

[0053] In S3, the adhesive resin composition is prepared by mixing the components and then stirring in stages, with the stirring parameters and intervals set to meet the requirements for uniform mixing of the components.

[0054] Here, the preparation of the adhesive resin composition requires first obtaining the winding resin, fumed silica powder, and powdered foam adhesive in proportion. The total preparation amount can be adjusted according to actual needs. The example preparation amount is 2kg winding resin, 100g fumed silica powder, and 500g powdered foam adhesive. Precisely preparing the ingredients in proportion can ensure the performance stability of the adhesive resin composition and avoid abnormal viscosity and foaming effect due to deviation in component ratio, which would affect the bonding quality.

[0055] Furthermore, the mixing is carried out using an electric mixer, and the mixing is carried out in 3 times, with each mixing time lasting 2 minutes. Multiple mixing can ensure that the components are fully mixed, avoid the agglomeration of fumed silica and foaming adhesive, and ensure that the resin composition has uniform and consistent properties.

[0056] Furthermore, a 2-minute interval is set between two consecutive stirring sessions. This stirring interval can alleviate the heat buildup generated during stirring, prevent high temperatures from affecting the performance of the components, and allow incompletely dispersed particles time to fully contact the stirring force, thereby improving the uniformity of mixing.

[0057] In S3, the adhesive resin composition is applied to uniformly cover the surface of the EPDM heat-insulating rubber, with the amount of application matching the target adhesive strength requirements.

[0058] Here, the amount of adhesive resin composition applied is controlled at 300 g / ㎡. Precise application ensures that there is enough adhesive medium on the surface of the heat insulation rubber, avoiding weak adhesion due to insufficient application, and preventing excessive application that would result in resin waste and excessive residue after curing.

[0059] Furthermore, during the coating process, it is necessary to ensure that the resin composition evenly covers the surface of the EPDM heat insulation rubber without any omissions or accumulations. Even coating can ensure that the thickness of the adhesive medium is consistent throughout the bonding interface, avoiding uneven bonding strength caused by local resin accumulation or lack, and improving the overall bonding reliability.

[0060] Furthermore, the coating operation should be carried out promptly after the layup operation to avoid contamination of the insulation rubber surface with impurities. Timely coating can reduce the chance of external impurities contaminating the insulation rubber surface, ensuring a clean bonding interface and creating conditions for good adhesion.

[0061] S4: Wrapping operation of EPDM insulating rubber coated with adhesive resin composition.

[0062] In S4, the winding operation includes longitudinal winding and circumferential winding, which forms a shell structure adapted to the usage scenario.

[0063] Here, the winding operation is carried out by a combination of longitudinal and circumferential winding according to conventional processes. The winding object is EPDM insulation rubber coated with adhesive resin composition and the mold as a whole. The combination of longitudinal and circumferential winding can form a three-dimensional mesh structure in the winding layer, so that the shell is subjected to uniform stress in all directions, which is suitable for the complex stress environment of the aerospace engine combustion chamber.

[0064] Furthermore, the winding tension needs to be controlled during the winding process to ensure that the winding layer adheres tightly to the surface of the adhesive resin composition. Appropriate winding tension can promote full contact between the winding layer and the adhesive resin, enhance the interfacial bonding force between the winding layer and the heat insulation rubber layer, and prevent loosening between layers.

[0065] Furthermore, after the winding is completed, a preliminary structure of the aerospace engine shell is formed, laying the foundation for subsequent curing and molding. The wound shell structure can constrain the heat insulation rubber layer, and together with the foaming pressure of the foaming adhesive during the subsequent curing process, it can further improve the bonding effect and the overall structural strength.

[0066] S5: Curing treatment is performed on the product after the S4 winding operation.

[0067] In S5, the curing process is a multi-stage heating and heat preservation process. After heating to the common curing temperature of the base material and the foaming component, the temperature is kept for a preset time, and then naturally cooled to a temperature suitable for subsequent processing.

[0068] Here, the initial stage of the curing process involves raising the room temperature to 80°C at a rate controlled at 25°C-30°C / h. After reaching 80°C, the temperature is maintained for 2 hours. During the maintenance period, a scraping operation is required. Slow heating can prevent the resin and foam from reacting too quickly due to a sudden temperature rise, which could generate internal stress. Maintaining the temperature at 80°C and scraping the adhesive can remove excess bonding resin, ensuring a smooth shell surface and creating stable conditions for subsequent stages of reaction.

[0069] Furthermore, after the first stage of heat preservation, the temperature is increased to 95℃ at a rate of 25℃-30℃ / h and kept for 3 hours. This stage of heating and heat preservation can promote the initial reaction of the winding resin and foam adhesive, gradually improve the bonding force of the bonding interface, and slow heating can still avoid the generation of internal stress.

[0070] Furthermore, the temperature is subsequently increased to 125℃ and held for 4 hours, then increased to 155℃ and held for 6 hours at the same rate. 155℃ is the maximum curing temperature for both the foam and the wrapping resin. This temperature can be adjusted according to the specific resin and foam type used. The multi-stage heating and holding process ensures that all components react fully. The maximum curing temperature of 155℃ ensures that the wrapping resin is completely cured and the foam is fully expanded, maximizing the bond strength. The adjustable temperature allows the process to be adapted to different types of materials, enhancing its versatility. In the later stages of curing, the heating source is turned off, the oven door is kept closed, and the fan is turned on to allow the product to cool naturally to 60℃. Natural cooling avoids uneven shrinkage of the shell structure caused by a sudden temperature drop, reduces internal stress, protects the bonding interface and the integrity of the overall structure, and ensures the dimensional accuracy and performance stability of the cured product.

[0071] This embodiment, compared to existing rubber-wound layer bonding technology, improves the bond strength between the wound layer and the insulation layer by more than 30% by adding a foaming adhesive mixture. The old process involved wrapping a 2mm thick one-way wound board around a 2mm insulation surface, and then applying 300g / m² of winding resin to the rubber surface. The new process involves wrapping a 2mm thick one-way wound board around a 2mm insulation surface, and then applying a mixture of 300g / m² winding resin and foaming adhesive to the rubber surface. The test results are as follows:

[0072]

[0073] The working principle and usage process of this invention are as follows: First, the mold is degreased, cleaned, and protected against contamination during tooling preparation to provide a clean and flat reference surface for the layup operation. Then, through overlapping, pre-vacuuming, and air-rolling operations during the layup process, the thermal insulation rubber layer is ensured to have a dense structure, a smooth surface, and no impurities, creating a good foundation for subsequent bonding. Subsequently, an adhesive resin composition containing winding resin, fumed silica, and powdered foam is prepared. Fumed silica increases the resin viscosity to prevent resin migration during curing, while the powdered foam forms a compatible curing system with the winding resin. After application, the thermal insulation is evenly covered. The rubber surface is then wrapped with a combination of longitudinal and circumferential winding to form an external constraint. During the multi-stage heating and heat preservation process in the curing stage, the foaming adhesive undergoes a foaming reaction simultaneously, generating inward expansion pressure. This, along with the pressure exerted by the winding layer on the insulation layer, forms a bidirectional force, prompting the adhesive resin to fully wet the interface between the insulation rubber and the winding layer. At the same time, the multi-stage slow heating and heat preservation ensure that the resin is completely cured and that all components react fully. Ultimately, through the synergistic effect of ensuring basic conditions, optimizing the anti-migration of the adhesive system, enhancing bidirectional pressure, and ensuring full curing, the bonding strength between the EPDM insulation and the metal inner wall is significantly improved, avoiding the problem of interface debonding.

[0074] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for bonding EPDM insulation to a metal inner wall, characterized in that, Includes the following steps: S1: Tooling preparation, the tooling including a mold for laying EPDM heat insulation rubber; S2: Perform a layup operation on the EPDM heat insulation rubber on the laying surface of the mold; S3: Prepare an adhesive resin composition comprising a base material, a tackifying component and a foaming component, and apply the adhesive resin composition to the surface of the EPDM heat-insulating rubber after the layup operation described in S2. S4: Wrapping operation of EPDM insulation rubber coated with adhesive resin composition; S5: Curing treatment is performed on the product after the winding operation described in S4.

2. The method for bonding EPDM insulation to a metal inner wall according to claim 1, characterized in that: In the adhesive resin composition, the base material is a winding resin, the tackifying component is fumed silica, the foaming component is powdered foam adhesive, and the components are mixed in proportions suitable for adhesive performance.

3. The method for bonding EPDM insulation to a metal inner wall according to claim 1, characterized in that: In S2, the layup operation adopts a covering overlap bonding, and the overlap form of adjacent EPDM insulation rubber sheets is selected according to their thickness, and the overlap width is adapted to the interlayer bonding requirements.

4. The method for bonding EPDM insulation to a metal inner wall according to claim 1, characterized in that: In S2, at least one pre-vacuuming operation is performed during the layup operation, and the vacuum level and duration of the pre-vacuuming are adapted to the layup degassing and shape preservation requirements.

5. The method for bonding EPDM insulation to a metal inner wall according to claim 1, characterized in that: In S3, the adhesive resin composition is prepared by mixing the components and then stirring in stages, with the stirring parameters and intervals set to meet the requirements for uniform mixing of the components.

6. The method for bonding EPDM insulation to a metal inner wall according to claim 1, characterized in that: In S3, the adhesive resin composition is applied to uniformly cover the surface of the EPDM heat-insulating rubber, with the amount of application matching the target adhesive strength requirement.

7. The method for bonding EPDM insulation to a metal inner wall according to claim 1, characterized in that: In S4, the winding operation includes longitudinal winding and circumferential winding, and after winding, a shell structure adapted to the usage scenario is formed.

8. The method for bonding EPDM insulation to a metal inner wall according to claim 1, characterized in that: In S5, the curing process is a multi-stage heating and heat preservation process. After heating to the common curing temperature of the base material and the foaming component, the temperature is kept for a preset time, and then naturally cooled to a temperature suitable for subsequent processing.

9. The method for bonding EPDM insulation to a metal inner wall according to claim 1, characterized in that: In S1, the tooling preparation includes cleaning the mold laying surface. The mold used for the first time needs to be degreased. When the cleaned mold laying surface is not used for the time being, anti-contamination covering measures should be taken.

10. The method for bonding EPDM insulation to a metal inner wall according to claim 1, characterized in that: In S2, during the layup operation, the amount of EPDM insulation rubber overflow is controlled to match the molding requirements. During the layup process, air rolling measures are taken to ensure a smooth surface. When laying the same layer or multiple layers, the overlapping edges are staggered.

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