Novel high-temperature-resistant corrosion-resistant aluminum alloy plastic-lined PP-RCT composite pipe

Abstract

The invention discloses a novel high-temperature-resistant and corrosion-resistant aluminum alloy plastic-lined PP-RCT composite pipe, and relates to the technical field of composite pipelines. The composite pipe is of a five-layer gradient composite structure, wherein the outer layer is an anodized aluminum alloy base body, and the inner surface is provided with laser micro-texture anchoring points; the secondary layer is a chromium-free Dacromet anti-corrosion layer, and the interface bonding force is improved through a three-dimensional network structure; the third layer is a gradient curing bonding layer which is cured by stages to eliminate thermal stress; the fourth layer is a dynamic stress compensation layer for absorbing the thermal expansion difference between the metal layer and the plastic layer; and the inner layer is a PP-RCT functional layer which has high temperature resistance and corrosion resistance. The end of the composite pipe is sealed through laser welding, an embedded intelligent monitoring system is integrated, and axial stress and temperature are monitored in real time. Compared with the prior art, the invention is suitable for pipeline systems under extreme working conditions of petrochemical engineering, ocean engineering, high-temperature fluid transportation and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite pipes, and in particular relates to a new type of PP-RCT composite pipe with high temperature resistance and corrosion resistance and aluminum alloy plastic lining. Background Art

[0002] In the field of pipeline engineering, aluminum alloy-lined plastic composite pipes, combining the advantages of metal and plastic, are widely used in various fluid transportation scenarios. Traditional aluminum alloy-lined plastic composite pipes typically adopt a simple two-layer structure: an outer aluminum alloy tube for rigid support and an inner plastic layer for conveying the medium. However, with the increasing performance requirements for pipelines in industrial production and construction projects, existing aluminum alloy-lined plastic composite pipes have gradually exposed many shortcomings.

[0003] In terms of high-temperature resistance, existing plastic inner layer materials, such as standard PP-R and PE-RT, have limited heat resistance limits and are prone to softening and deformation in high-temperature environments. This reduces the pipe's pressure-bearing capacity and makes it unable to meet the requirements for long-term, stable transportation of high-temperature fluids. Furthermore, high temperatures accelerate aging of the interface between the metal and plastic layers, reducing interlayer bonding strength and causing delamination.

[0004] In terms of corrosion resistance, although the aluminum alloy layer undergoes surface treatments such as anodizing, its protection is still insufficient in corrosive environments such as strong acids, alkalis, and salt spray. The anodized film is easily damaged, which in turn causes corrosion of the aluminum alloy substrate. Once the metal layer is damaged, the internal plastic layer also loses its protection and ages faster, significantly shortening the pipe's service life.

[0005] Furthermore, traditional composite pipes lack effective compensation for differential thermal expansion in their structural design. Under conditions of significant temperature fluctuations, the stress generated by the different thermal expansion coefficients between the metal and plastic layers can easily lead to pipe rupture or leakage at joints. Furthermore, the sealing structure and connection methods at the pipe ends also suffer from poor sealing effectiveness and complex installation, making them difficult to adapt to complex engineering applications.

[0006] To solve the above problems, technicians in this field have made many attempts, but there is no aluminum alloy lined plastic composite pipe that can effectively integrate multiple properties such as high temperature resistance, corrosion resistance, stress compensation and reliable sealing. Therefore, there is an urgent need to develop a new type of composite pipe to meet market demand. Summary of the Invention

[0007] The present invention aims to provide a new type of high-temperature and corrosion-resistant aluminum alloy lined plastic PP-RCT composite pipe. Through a unique five-layer composite structure design, innovative material formulation and advanced manufacturing technology, it effectively addresses the shortcomings of existing aluminum alloy lined plastic composite pipes in terms of high-temperature resistance, corrosion resistance, stress compensation and sealing performance, improves the overall performance and service life of the pipeline, and reduces maintenance costs in engineering applications.

[0008] To solve the above technical problems, the present invention is achieved through the following technical solutions: The present invention is a new type of PP-RCT composite pipe with high temperature and corrosion resistance and aluminum alloy lining plastic, comprising a five-layer structure compounded sequentially from the outside to the inside: Metal matrix layer: The outer surface of the aluminum alloy tube is anodized to form an oxide film, and the inner surface has laser micro-textured anchor points; Anti-corrosion layer: The anti-corrosion layer is a chromium-free Dacromet coating, comprising zinc-based alloy particles and a silicate binder, and is sprayed on the inner surface of the aluminum alloy tube to form a three-dimensional network structure; Gradient curing adhesive layer: comprising thermosetting resin and nanoparticles, coated on the inner surface of the anti-corrosion layer and cured in stages to form a gradient cross-linked structure; Dynamic stress compensation layer: a nanoparticle-reinforced thermoplastic elastomer in contact with the gradient-cured adhesive layer, used to absorb the thermal expansion difference between the metal and plastic layers; PP-RCT functional layer: contains polyphenylene sulfide, polyamide, ethylene-vinyl alcohol copolymer and reinforcing fiber blend, and is coaxially coextruded with the dynamic stress compensation layer; The end of the composite pipe is provided with a laser welding sealing structure to achieve a non-interface leakage connection between the metal layer and the plastic layer.

[0009] As a preferred technical solution of the present invention, the thickness of the oxide film on the outer surface of the metal base layer is 5-20 μm, the depth of the laser micro-texturing anchor points on the inner surface is 50-100 μm, and the spacing is 0.5-1.0 mm.

[0010] As a preferred technical solution of the present invention, the anti-corrosion layer is a chromium-free Dacromet coating, the formula of which comprises: Metal powder: zinc powder content 45-55wt%, aluminum powder content 10-20wt%; Silane coupling agent: γ-aminopropyltriethoxysilane content 3-5wt%; Inorganic binder: silica sol content 10-15wt%; Deionized water balance.

[0011] As a preferred technical solution of the present invention, the gradient cured adhesive layer includes: Epoxy resin E-51 content 65-75wt%; Phenolic resin content 20-30wt%; Nano-Al2O3 with surface modified by γ-aminopropyltriethoxysilane, content of 5-10wt%.

[0012] As a preferred technical solution of the present invention, the gradient curing adhesive layer adopts a staged curing process: Pre-curing stage: temperature 100-120℃, time 1-5h; Main curing stage: temperature 180-220℃, time 2-8h; Post-curing stage: temperature 220-260℃, time 0.5-2h.

[0013] As a preferred technical solution of the present invention, the base material of the dynamic stress compensation layer is selected from one or more of polyurethane elastomer, polyetheretherketone, and polyimide, and the reinforcing phase is nano-silicon dioxide, carbon nanotubes or graphene, with a volume fraction of 5-20%.

[0014] As a preferred technical solution of the present invention, in the PPP-RCT functional layer: The polyphenylene sulfide content is 50-60wt% and has a β-crystal structure; The polyamide is a semi-crystalline polyamide with a content of 25-30wt%; The vinyl alcohol unit content of the ethylene-vinyl alcohol copolymer is ≥44 mol%, and the content is 10-15 wt%; Maleic anhydride grafted POE, content 5-10wt%, The reinforcing fibers are carbon fibers or glass fibers, and the content thereof is 5-15 wt %.

[0015] As a preferred technical solution of the present invention, the laser welding sealing structure includes: The aluminum alloy flange is expanded and the inner diameter is closed to the outer diameter of the PPP-RCT layer; The hot melt adhesive pre-coating layer is an ethylene-vinyl alcohol copolymer hot melt adhesive, which forms a firm connection with the aluminum alloy layer and the PP-RCT functional layer through a hot melt process.

[0016] As a preferred technical solution of the present invention, an embedded intelligent monitoring system is also included, including: Stress monitoring unit: The stress sensor of the intelligent monitoring system is a distributed fiber Bragg grating sensor, which is buried in the middle position of the dynamic stress compensation layer and the PP-RCT functional layer in the thickness direction, and can simultaneously monitor the axial stress; Temperature monitoring unit: PT100 thin film sensor, attached to the outer surface of the metal base layer; Data transmission module: NB-IoT wireless module, integrated into the end of the tube body.

[0017] As a preferred technical solution of the present invention, it also includes: an integrally formed flange connector, the sealing surface of which is fused and bonded to the PP-RCT functional layer; and a stainless steel reinforcement ring embedded in the flange.

[0018] The present invention has the following beneficial effects: Excellent high-temperature resistance: The polyphenylene sulfide in the PP-RCT functional layer has a β-crystal structure. Combined with the high-temperature resistance design of the gradient-cured adhesive layer, the composite pipe can operate stably for a long time in a high-temperature environment of 120°C-150°C. Compared with traditional aluminum alloy lined plastic composite pipes, the high-temperature resistance is significantly improved, effectively meeting the needs of high-temperature fluid transportation.

[0019] Excellent corrosion resistance: The anodic oxide film of the metal base layer and the chromium-free Dacromet coating of the anti-corrosion layer form a double protection, which can resist the erosion of various corrosive media such as strong acids, alkalis, salt spray, etc., greatly extending the service life of the pipeline in corrosive environments.

[0020] Good stress compensation capability: The dynamic stress compensation layer uses nanoparticle-reinforced thermoplastic elastomer, which can effectively absorb the stress generated by the difference in thermal expansion coefficient between the metal and plastic layers, effectively preventing pipeline rupture and delamination caused by thermal stress.

[0021] Reliable sealing performance: The laser-welded sealing structure at the end and the one-piece flange connector ensure the sealing and reliability of the pipe connection parts, avoiding fluid leakage problems.

[0022] Intelligent monitoring and management: The embedded intelligent monitoring system can monitor the stress and temperature status of the pipeline in real time and transmit the data to the monitoring terminal through the NB-IoT wireless module, realizing intelligent management of the pipeline operation status, facilitating the timely detection and treatment of potential problems, reducing maintenance costs, and improving the operating efficiency and safety of the pipeline system.

[0023] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 Schematic diagram of the cross-sectional structure of the PP-RCT composite pipe of the present invention; Figure 2 Schematic diagram of the microstructure of the laser microtexturing anchor point on the inner surface of the metal matrix layer; Figure 3 Flowchart of the staged curing process for the gradient-cured bonding layer; Figure 4 This is the intelligent monitoring system architecture of the present invention; Figure 5This is a process flow chart of the composite pipe manufacturing process of the present invention; In the accompanying drawings, the components represented by the reference numerals are as follows: 1-metal matrix layer, 2-anti-corrosion layer, 3-gradient curing adhesive layer, 4-dynamic stress compensation layer, 5-PP-RCT functional layer, 6-anchor point. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] like Figure 1-5 Shown: A new type of PP-RCT composite pipe with high temperature and corrosion resistance and aluminum alloy lining plastic, including a five-layer structure compounded from the outside to the inside, as well as an end sealing structure, an intelligent monitoring system and flange connectors, as follows: Metal Matrix Layer: Using an aluminum alloy tube as the foundation, the outer surface is anodized to form a 5-20μm thick oxide film, which effectively isolates the external environment and provides initial protection for the pipe. Laser processing is used to create micro-textured anchor points on the inner surface, with a depth of 50-100μm and a spacing of 0.5-1.0mm. These anchor points significantly enhance the mechanical bond with the subsequent anti-corrosion layer, ensuring stability between the layers of the composite pipe.

[0028] Anti-corrosion coating: This chromium-free Dacromet coating is sprayed onto the inner surface of the aluminum alloy tube. Its formula includes metal powder (zinc powder content 45-55wt%, aluminum powder content 10-20wt%). Zinc and aluminum powders serve as the primary anti-corrosion ingredients, providing effective cathodic protection. A silane coupling agent (γ-aminopropyltriethoxysilane content 3-5wt%) improves the adhesion between the coating and the aluminum alloy substrate. An inorganic binder (silica sol content 10-15wt%) provides film support. Deionized water is the balance. After mixing, these ingredients are sprayed onto the inner surface of the aluminum alloy tube, forming a three-dimensional network structure that effectively resists corrosion from various corrosive media.

[0029] The gradient-cured adhesive layer comprises a thermosetting resin and nanoparticles. The specific composition and content are as follows: 65-75wt% epoxy resin E-51, providing good bond strength; 20-30wt% phenolic resin, enhancing high-temperature resistance; and 5-10wt% nano-Al2O3, surface-modified with γ-aminopropyltriethoxysilane, enhancing the coating's hardness and wear resistance. This layer is applied to the inner surface of the anti-corrosion layer and uses a staged curing process: a pre-curing stage at 100-120°C for 1-5 hours; a main curing stage at 180-220°C for 2-8 hours; and a post-curing stage at 220-260°C for 0.5-2 hours. This staged curing creates a gradient cross-linked structure, enabling the layer to better adapt to interlayer stress variations and enhancing adhesion to both the anti-corrosion layer and the dynamic stress compensation layer.

[0030] Dynamic stress compensation layer: Composed of a nanoparticle-reinforced thermoplastic elastomer, the matrix material is selected from one or more of polyurethane elastomer, polyetheretherketone, and polyimide, and the reinforcement phase is nanosilica, carbon nanotubes, or graphene, with a volume fraction of 5-20%. This layer, in contact with the gradient-cured adhesive layer, effectively absorbs stress generated by the difference in thermal expansion coefficients between the metal and plastic layers, preventing cracking or delamination of the pipeline due to thermal stress and ensuring stable operation under conditions of large temperature fluctuations.

[0031] The PP-RCT functional layer comprises a blend of polyphenylene sulfide (PPS), polyamide (PA), ethylene-vinyl alcohol (EVA) copolymer (EVA), and reinforcing fibers. Specifically, the PPS content is 50-60% by weight, with a β-crystal structure, giving the pipe excellent high-temperature resistance. The PA is a semi-crystalline PA at 25-30% by weight, enhancing the pipe's toughness. The EVA copolymer contains ≥44 mol% EVA units, with a content of 10-15% by weight, providing excellent oxygen barrier properties. Maleic anhydride-grafted POE (PAE) contains 5-10% by weight to improve compatibility between the components. The reinforcing fibers are carbon or glass fibers, at a content of 5-15% by weight, enhancing the pipe's mechanical strength. This layer is coaxially extruded with the dynamic stress compensation layer, directly contacting the conveying medium and meeting the pipe's functional requirements.

[0032] End sealing structure: The end of the composite pipe is equipped with a laser welding sealing structure, which includes aluminum alloy flanging and flaring, closing the inner diameter to the outer diameter of the PP-RCT layer, and then applying ethylene-vinyl alcohol copolymer hot melt adhesive as a pre-coating layer. Through the hot melt process, the hot melt adhesive forms a firm connection with the aluminum alloy layer and the PP-RCT functional layer, realizing a non-interfacial leakage connection between the metal layer and the plastic layer, ensuring the sealing and reliability of the pipeline connection.

[0033] Embedded intelligent monitoring system: This system includes a stress monitoring unit, a temperature monitoring unit, and a data transmission module. The stress monitoring unit uses a distributed fiber Bragg grating sensor, embedded midway between the dynamic stress compensation layer and the PP-RCT functional layer, to simultaneously monitor axial stress. The temperature monitoring unit is a PT100 thin-film sensor attached to the outer surface of the metal substrate, which monitors the external ambient temperature of the pipeline in real time. The data transmission module is an NB-IoT wireless module, integrated into the end of the pipe body, which transmits monitoring data in real time to the monitoring terminal, facilitating timely monitoring of pipeline operating status and enabling intelligent management.

[0034] One-piece flange connector: The composite pipe is also equipped with an one-piece flange connector, the sealing surface of which is fused with the PP-RCT functional layer to ensure the sealing of the connection part; the flange is embedded with a stainless steel reinforcement ring to enhance the strength and rigidity of the flange, facilitating the connection and installation of the pipeline and other equipment.

[0035] A specific embodiment of the present invention is as follows: Example 1: Chemical corrosive medium transportation pipeline Material preparation Metal matrix layer: 6061 aluminum alloy tube with an outer diameter of 100mm and a wall thickness of 3mm was selected. The outer surface was anodized and the electrolyte was sulfuric acid (concentration 180g / L, temperature 18℃, current density 1.5A / dm 2 ) for 120 minutes to form an oxide film with a thickness of 15μm; the inner surface is processed by laser processing technology, with a laser power of 20W and a pulse frequency of 50kHz, to produce micro-textured honeycomb anchor points with a depth of 80μm and a spacing of 0.8mm.

[0036] Anti-corrosion coating: A chromium-free Dacromet coating was prepared by uniformly mixing 50wt% zinc powder, 15wt% aluminum powder, 4wt% γ-aminopropyltriethoxysilane, 13wt% silica sol, and the balance deionized water. The coating was applied electrostatically to the inner surface of the aluminum alloy tube to form an 8μm-thick coating, which was then cured at 250°C for 30 minutes to form a three-dimensional network structure.

[0037] Gradient-cured adhesive layer: Epoxy resin E-51 (70 wt%), phenolic resin (25 wt%), and nano-Al₂O₃ modified with γ-aminopropyltriethoxysilane (5 wt%) were mixed uniformly and applied to the inner surface of the anti-corrosion layer using a roller coating to a thickness of 0.3 mm. Curing was performed in stages, using a pre-curing phase at 110°C for 3 hours, a main curing phase at 200°C for 5 hours, and a post-curing phase at 240°C for 1 hour, to form a gradient cross-linked structure.

[0038] Dynamic stress compensation layer: Polyurethane elastomer is selected as the matrix material, and nano-silica with a volume fraction of 15% is added as the reinforcing phase. It is blended and granulated through a twin-screw extruder, and then an elastomer layer with a thickness of 1 mm is made by an extrusion molding process, which is then bonded to the gradient curing adhesive layer.

[0039] PP-RCT functional layer: Polyphenylene sulfide (55wt%), semi-crystalline polyamide PA12 (28wt%), ethylene-vinyl alcohol copolymer (12wt%), maleic anhydride grafted POE (8wt%), and carbon fiber (7wt%) are mixed evenly, melt-blended in a twin-screw extruder at 300°C, and then extruded through a coaxial co-extrusion die with a dynamic stress compensation layer to form a functional layer with a thickness of 2 mm.

[0040] End seals and flange forming Laser welding sealing structure: aluminum alloy flanging flaring: inner diameter closing to the outer diameter of PP-RCT layer (interference amount 0.2mm), forming a mechanical fit; Hot melt adhesive pre-coating: EVOH hot melt adhesive (melting point 190°C), thickness 0.3mm, forms a chemical bond with the metal-plastic layer through a hot melt process (temperature 200°C, pressure 2MPa); One-piece flange connector: Material: PP-RCT functional layer and 316L stainless steel reinforcement ring (thickness 2.5mm) are integrally injection molded; Sealing surface: fused with the PP-RCT layer, tensile strength 420MPa, pressure resistance grade PN25.

[0041] Embedded intelligent monitoring system installation Stress monitoring unit: Distributed FBG sensor, buried in the middle of the thickness between the dynamic stress compensation layer and the PP-RCT layer, connected to the NB-IoT module via a fiber fusion splicer; Temperature monitoring unit: PT100 thin film sensor (thickness 60μm), attached to the outer surface of the metal base layer, response time 3s, accuracy ±0.1℃.

[0042] Data transmission module: NB-IoT module (operating frequency band 800MHz), data transmission cycle 1 minute, abnormal data (stress exceeding limit ≥80% or temperature ≥100℃) is uploaded to the cloud in real time.

[0043] Pipeline assembly The prepared layers were then laminated sequentially and bonded tightly together through a hot-pressing process. The pipe ends were then flanging with aluminum alloy to reduce the inner diameter to the same diameter as the outer diameter of the PP-RCT functional layer. Ethylene-vinyl alcohol copolymer hot-melt adhesive (melt index 1.0 g / 10 min) was then applied to a thickness of 0.3 mm. Laser welding was performed at a power of 400 W and a speed of 1 m / min, achieving a leak-free connection between the metal and plastic layers.

[0044] A distributed fiber Bragg grating sensor is buried in the middle position between the dynamic stress compensation layer and the PP-RCT functional layer in the thickness direction as a stress monitoring unit; a PT100 thin film sensor is attached to the outer surface of the metal base layer as a temperature monitoring unit; and the NB-IoT wireless module is integrated at the end of the pipe body.

[0045] One-piece flange connectors are installed at both ends of the pipeline. A 2mm thick stainless steel reinforcement ring is embedded in the flange, and the sealing surface and the PP-RCT functional layer are melted together through a hot melt process.

[0046] Performance Testing Implementation effect verification Temperature resistance test: Crude oil (containing 500ppm chloride ions) at 110℃ is continuously transported for 1000h, and the pipeline has no deformation or leakage; Corrosion resistance test: marine environment (salt spray concentration 5%, ultraviolet radiation intensity 0.7W / m 2 ) After exposure for 2500h, the anti-corrosion layer has no rust or shedding; Interface bonding test: After thermal cycle test (-40℃ to 150℃, 1000 times), the shear strength is 17.5MPa and there is no delamination; Intelligent monitoring test: When a leak is simulated (pressure drops by 10%), the system issues an early warning within 5 seconds, with a positioning accuracy of ±1m.

[0047] 3. Key performance test data

[0048] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0049] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A new type of PP-RCT composite pipe with high temperature and corrosion resistance and aluminum alloy lining, characterized by: It includes five layers of structure compounded from outside to inside: Metal matrix layer: The outer surface of the aluminum alloy tube is anodized to form an oxide film, and the inner surface has laser micro-textured anchor points; Anti-corrosion layer: The anti-corrosion layer is a chromium-free Dacromet coating, comprising zinc-based alloy particles and a silicate binder, and is sprayed on the inner surface of the aluminum alloy tube to form a three-dimensional network structure; Gradient curing adhesive layer: comprising thermosetting resin and nanoparticles, coated on the inner surface of the anti-corrosion layer and cured in stages to form a gradient cross-linked structure; Dynamic stress compensation layer: a nanoparticle-reinforced thermoplastic elastomer in contact with the gradient-cured adhesive layer, used to absorb the thermal expansion difference between the metal and plastic layers; PP-RCT functional layer: contains polyphenylene sulfide, polyamide, ethylene-vinyl alcohol copolymer and reinforcing fiber blend, and is coaxially coextruded with the dynamic stress compensation layer; The end of the composite pipe is provided with a laser welding sealing structure to achieve a non-interface leakage connection between the metal layer and the plastic layer.

2. The high temperature and corrosion resistant aluminum alloy lined plastic new PP-RCT composite pipe according to claim 1 is characterized in that: The thickness of the oxide film on the outer surface of the metal base layer is 5-20 μm, the depth of the laser micro-texturing anchor points on the inner surface is 50-100 μm, and the spacing is 0.5-1.0 mm.

3. The high temperature and corrosion resistant aluminum alloy lined plastic new PP-RCT composite pipe according to claim 1 is characterized in that: The anti-corrosion layer is a chromium-free Dacromet coating, the formula of which includes: Metal powder: zinc powder content 45-55wt%, aluminum powder content 10-20wt%; Silane coupling agent: γ-aminopropyltriethoxysilane content 3-5wt%; Inorganic binder: silica sol content 10-15wt%; Deionized water balance.

4. The high temperature and corrosion resistant aluminum alloy lined plastic new PP-RCT composite pipe according to claim 1 is characterized in that: The gradient cured adhesive layer comprises: Epoxy resin E-51 content 65-75wt%; Phenolic resin content 20-30wt%; Nano-Al2O3 with surface modified by γ-aminopropyltriethoxysilane, content of 5-10wt%.

5. The high temperature and corrosion resistant aluminum alloy lined plastic new PP-RCT composite pipe according to claim 4 is characterized in that: The gradient curing adhesive layer adopts a staged curing process: Pre-curing stage: temperature 100-120℃, time 1-5h; Main curing stage: temperature 180-220℃, time 2-8h; Post-curing stage: temperature 220-260℃, time 0.5-2h.

6. The high temperature and corrosion resistant aluminum alloy lined plastic new PP-RCT composite pipe according to claim 1 is characterized in that: The base material of the dynamic stress compensation layer is selected from one or more of polyurethane elastomer, polyetheretherketone, and polyimide, and the reinforcing phase is nano-silicon dioxide, carbon nanotubes, or graphene, with a volume fraction of 5-20%.

7. The high temperature and corrosion resistant aluminum alloy lined plastic new PP-RCT composite pipe according to claim 1 is characterized in that: In the PPP-RCT functional layer: The polyphenylene sulfide content is 50-60wt% and has a β-crystal structure; The polyamide is a semi-crystalline polyamide with a content of 25-30wt%; The vinyl alcohol unit content of the ethylene-vinyl alcohol copolymer is ≥44 mol%, and the content is 10-15 wt%; Maleic anhydride grafted POE, content 5-10wt%, The reinforcing fibers are carbon fibers or glass fibers, and the content thereof is 5-15 wt %.

8. The high temperature and corrosion resistant aluminum alloy lined plastic new PP-RCT composite pipe according to claim 1 is characterized in that: The laser welding sealing structure comprises: The aluminum alloy flange is expanded and the inner diameter is closed to the outer diameter of the PPP-RCT layer; The hot melt adhesive pre-coating layer is an ethylene-vinyl alcohol copolymer hot melt adhesive, which forms a firm connection with the aluminum alloy layer and the PP-RCT functional layer through a hot melt process.

9. The high temperature and corrosion resistant aluminum alloy lined plastic new PP-RCT composite pipe according to claim 1, characterized in that: Also includes an embedded intelligent monitoring system, including: Stress monitoring unit: The stress sensor of the intelligent monitoring system is a distributed fiber Bragg grating sensor, which is buried in the middle position of the dynamic stress compensation layer and the PP-RCT functional layer in the thickness direction, and can simultaneously monitor the axial stress; Temperature monitoring unit: PT100 thin film sensor, attached to the outer surface of the metal base layer; Data transmission module: NB-IoT wireless module, integrated into the end of the tube body.

10. The high temperature and corrosion resistant aluminum alloy lined plastic new PP-RCT composite pipe according to claim 1, characterized in that: Also includes: The sealing surface of the integrally formed flange connection piece is melt-bonded with the PP-RCT functional layer; the flange is embedded with a stainless steel reinforcement ring.

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