Pipe repair profile based on a co-extrusion composite process

Abstract

The application discloses a pipeline repair profile based on a co-extrusion composite process and relates to the technical field of pipeline repair materials. The profile base plate comprising an upper hard polyvinyl chloride surface layer, a middle foamed core layer and a lower hard polyvinyl chloride surface layer is prepared based on the co-extrusion composite process. Through the three-layer co-extrusion composite structure design, the upper and lower hard polyvinyl chloride surface layers are used to ensure the overall strength, hardness and weather resistance and wear resistance of the profile. The middle foamed core layer can effectively absorb external impact energy and significantly improve the toughness and impact resistance of the profile. Meanwhile, the foamed core layer can reduce the overall density and weight of the profile, reduce the transportation and construction difficulty and better adapt to the pipeline repair demand under complex working conditions. In addition, the three-layer co-extrusion composite process ensures the high bonding strength between the layers, makes the layers of the profile more closely combined, the structure more stable, avoids the delamination and falling of the layers and further improves the reliability and durability of the pipeline repair.

Description

Technical Field

[0001] This invention relates to the field of pipeline repair materials technology, and in particular to a pipeline repair profile based on a co-extrusion composite process. Background Technology

[0002] Existing pipe repair profiles are made of a single solid rigid polyvinyl chloride material with low toughness. They have poor impact resistance when subjected to external impacts (such as construction disturbance, ground subsidence, or frost heave) during construction or pipeline operation, and are prone to brittle cracking or breakage, affecting the structural integrity and service life of the inner lining pipe. In addition, the profiles have high overall density, making transportation and construction difficult, and they are not suitable for pipe repair under complex working conditions. Summary of the Invention

[0003] This invention provides a pipe repair profile based on a co-extrusion composite process to solve the problems of low toughness, poor impact resistance, and high transportation and construction difficulty in existing pipe repair profiles.

[0004] This invention provides a pipe repair profile based on a co-extrusion composite process. The pipe repair profile based on the co-extrusion composite process includes a profile base plate formed by the co-extrusion composite process. The profile base plate includes an upper rigid polyvinyl chloride surface layer, an intermediate foamed core layer, and a lower rigid polyvinyl chloride surface layer.

[0005] The aforementioned pipe repair profile based on co-extrusion composite technology is prepared by co-extrusion composite process to obtain a profile base plate comprising an upper rigid PVC surface layer, a middle foamed core layer, and a lower rigid PVC surface layer. Compared with existing technologies, this invention, through a three-layer co-extrusion composite structure design, utilizes the upper and lower rigid PVC surface layers to ensure the overall strength, hardness, and weather resistance and wear resistance of the profile; the middle foamed core layer can effectively absorb external impact energy, significantly improving the toughness and impact resistance of the profile, effectively avoiding brittle cracking or damage under external forces such as construction disturbance, ground subsidence, or frost heave, ensuring the structural integrity of the inner lining pipe and extending its service life. At the same time, the foamed core layer can reduce the overall density and weight of the profile, reducing transportation and construction difficulty, improving construction efficiency, and better adapting to the pipe repair needs under complex working conditions. In addition, the three-layer co-extrusion composite process ensures high bonding strength between layers, making the layers of the profile more tightly bonded and the structure more stable, avoiding interlayer delamination, and further improving the reliability and durability of pipe repair. Attached Figure Description

[0006] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0007] Figure 1 This is a schematic diagram of the profile base plate of the pipe repair profile based on co-extrusion composite process in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the cross-sectional structure of the pipe repair profile based on co-extrusion composite process in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the cell structure of the intermediate foam core layer in Embodiment 9 of the present invention. Detailed Implementation

[0008] 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.

[0009] In Embodiment 1, this embodiment provides a pipe repair profile based on co-extrusion composite process. The pipe repair profile based on co-extrusion composite process includes a profile base plate formed by co-extrusion composite process. The profile base plate includes an upper rigid polyvinyl chloride surface layer, an intermediate foamed core layer and a lower rigid polyvinyl chloride surface layer.

[0010] Co-extrusion composite process refers to a process that uses multiple extruders to independently plasticize materials with different compositions or ratios, and then simultaneously extrudes the resulting multiple different melts into the same co-extrusion die to composite and form a multi-layered product in one step. The profile base plate refers to the basic load-bearing plate extending along the length of the pipe repair profile. It is used to bear external loads during spiral winding, provide ring stiffness, and serve as the base for auxiliary structures such as reinforcing ribs and locking mechanisms. The upper rigid PVC surface layer refers to the solid rigid PVC layer located on the topmost layer of the profile base plate, facing the water flow side of the pipe cavity. It is used to ensure the overall yield strength, ring stiffness, and weather resistance of the pipe repair profile. The intermediate foamed core layer refers to the PVC foam material layer located between the upper and lower rigid PVC surface layers. It is used to absorb external impact energy and provide sound damping performance. The lower rigid PVC surface layer refers to the solid rigid PVC layer located at the bottom of the profile base plate, facing the inner wall of the old pipe to be repaired. Its formula and performance are the same as the upper rigid PVC surface layer. Together with the upper rigid PVC surface layer, it is used to ensure the overall yield strength, ring stiffness and weather resistance of the pipe repair profile, and to provide a stable interlayer bonding force with the inner wall of the old pipe.

[0011] In this embodiment, the co-extrusion composite process is an ABA three-layer co-extrusion composite process. The profile base plate is also provided with T-shaped longitudinal reinforcing ribs, end lips, sealing strips, male and female locking latches, all of which are made of solid rigid polyvinyl chloride material.

[0012] In this embodiment, the profile base plate is also provided with additional structures such as T-shaped longitudinal reinforcing ribs, end lips, sealing strips, male and female locks, all of which are made of solid rigid polyvinyl chloride. Figure 1 The image shown is a schematic diagram of the cross-sectional structure of the pipe repair profile; as shown... Figure 2 The diagram shows the structure of the profile base plate. A1 is the upper rigid PVC surface layer, B is the middle foamed core layer, and A2 is the lower rigid PVC surface layer. A1, B, and A2 together constitute the pipe repair profile base plate. w e is the total thickness of the profile base plate (in mm), e0 is the maximum height of the profile (in mm), e R 1 is the height of the male lock (in mm); w is the effective unfolded width of the profile cross-section (excluding the buckle, in mm); w1 is the width of the profile cross-section (in mm); 1 and 3 are both male locks, 5 and 6 are both female locks; 2 is the end lip; 4 is the sealing strip.

[0013] This embodiment presents a pipe repair profile based on a co-extrusion composite process. Through this process, a profile base plate is prepared comprising an upper rigid PVC surface layer, a middle foamed core layer, and a lower rigid PVC surface layer. Compared to existing technologies, this invention utilizes a three-layer co-extrusion composite structure design. The upper and lower rigid PVC surface layers ensure the overall strength, hardness, and weather resistance of the profile. The middle foamed core layer effectively absorbs external impact energy, significantly improving the profile's toughness and impact resistance. This effectively prevents brittle cracking or damage under external forces such as construction disturbances, ground subsidence, or frost heave, ensuring the structural integrity of the inner lining pipe and extending its service life. Simultaneously, the foamed core layer reduces the overall density and weight of the profile, lowering transportation and construction difficulty, improving construction efficiency, and better adapting to the pipe repair needs under complex working conditions. Furthermore, the three-layer co-extrusion composite process ensures high bonding strength between the layers, resulting in a tighter bond and more stable structure, preventing delamination and further enhancing the reliability and durability of pipe repair.

[0014] In Example 2, the profile base plate includes a three-layer co-extruded composite profile obtained by using three extruders to plasticize the raw materials of the upper rigid PVC surface layer, the middle foamed core layer, and the lower rigid PVC surface layer, and then simultaneously extruding them into a three-layer co-extrusion mold for molding.

[0015] The three extruders refer to three independent extrusion units, each used to plasticize the raw materials for the upper rigid PVC surface layer, the middle foamed core layer, and the lower rigid PVC surface layer, respectively. Plasticization refers to the process of transforming powdered or granular solid PVC raw materials (such as resin and various additives) into a uniform, continuous melt with certain fluidity and plasticity through heating, shearing, mixing, and melting within the extruder. Three-layer co-extrusion mold refers to a special composite molding mold with three independent melt channels, which respectively transport the melt of the upper rigid PVC surface layer, the melt of the middle foamed core layer, and the melt of the lower rigid PVC surface layer. The mold cavity is designed according to a preset cross-section, so that the three melts are composited in a layered manner in the mold core or mold lip area in an ABA sequence. At the same time, the rigid PVC melt is diverted to form T-shaped longitudinal reinforcing ribs, end lips, sealing strips, male and female locking buckles, etc. The melts of each structure are thermally melted and bonded with the melt of the three-layer base plate in the mold and are simultaneously shaped. After extrusion, an integrated profile is formed with an ABA three-layer structured profile base plate and the remaining structures of solid rigid PVC (T-shaped longitudinal reinforcing ribs, end lips, sealing strips, male and female locking buckles, etc.). The interlayer bonding is firm and the layers do not mix. Molding process refers to the process where the molten structural elements and the three-layer base plate are thermally melted and bonded together in the mold, simultaneously shaped, and then extruded through the die orifice to initially form a continuous profile with a preset cross-sectional structure (including the profile base plate, T-shaped longitudinal reinforcing ribs, end lips, sealing strips, male and female locking latches). A three-layer co-extrusion composite structure refers to a three-layer integrated structure formed in one piece through a co-extrusion process, without subsequent bonding or splicing. Extruded profiles refer to long strip-shaped plastic products that are continuously produced through an extrusion process, with a fixed cross-sectional shape and a length that can be cut as needed.

[0016] In this embodiment, the extruded profile with a three-layer co-extrusion composite structure is a long strip of plastic sheet suitable for pipe repair, prepared based on the ABA three-layer co-extrusion composite process. The three extruders are three single-screw extruders, or a combination of a twin-screw extruder and a single-screw extruder. Preferably, the extruder used to form the upper rigid PVC surface layer is an SJ60 single-screw extruder, the extruder used to form the middle foamed core layer is an SJ60 twin-screw extruder, and the extruder used to form the lower rigid PVC surface layer is an SJ45 single-screw extruder.

[0017] This embodiment of the pipe repair profile based on co-extrusion composite technology involves using three extruders to plasticize the raw materials for the upper, middle, and lower layers, which are then simultaneously extruded into a three-layer co-extrusion die for one-time molding. The three layers are simultaneously composited in a molten state and molded as a single unit, improving interlayer peel strength, ensuring tight interlayer fusion and high bonding strength, effectively preventing delamination and guaranteeing the long-term structural integrity and durability of the inner liner. Independent control of the three-layer raw material formulation and extrusion parameters allows for precise matching of the differentiated performance requirements of the surface layer (high strength, high hardness, weather resistance, and wear resistance) and the core layer (high toughness, high impact resistance, and lightweight). The continuous co-extrusion molding process offers high production efficiency and uniform, stable product quality. The profile as a whole combines excellent mechanical properties with lightweight advantages, better meeting the long-term safe use requirements of pipe repair under complex working conditions.

[0018] In Example 3, the raw materials for the upper rigid PVC surface layer and the lower rigid PVC surface layer each independently include: PVC resin, heat stabilizer, calcium carbonate, impact modifier, acrylate processing aid, and titanium dioxide.

[0019] Polyvinyl chloride (PVC) resin is the base material of pipe repair profiles, providing basic mechanical properties (such as rigidity and strength) and processing performance. Heat stabilizers (such as calcium-zinc composite stabilizers or organotin stabilizers) are used to inhibit thermal degradation of PVC during processing (such as extrusion, heating, or shearing) (e.g., decomposition, discoloration, or dehydrochlorination). Calcium carbonate is an inorganic filler used to reduce raw material usage and improve profile hardness, rigidity, and dimensional stability. Impact modifiers (such as chlorinated polyethylene, acrylate impact modifiers, acrylonitrile-butadiene-styrene copolymers, or methyl methacrylate-butadiene-styrene copolymers) are used to improve the toughness and impact resistance of rigid PVC and reduce brittle cracking. Acrylate processing aids (ACR processing aids) are mainly copolymers of methyl methacrylate (MMA) and butyl acrylate (BA), used to improve the melt flowability, plasticization uniformity, and surface gloss of PVC resin, and enhance extrusion molding stability. Titanium dioxide refers to the white inorganic pigment titanium dioxide (such as rutile titanium dioxide), which is used to provide high whiteness (making the profile appear white) and hiding power, resist ultraviolet aging and yellowing, and improve the weather resistance and appearance stability of the polyvinyl chloride surface.

[0020] In this embodiment, the K-value (viscosity constant) of the polyvinyl chloride resin in the raw materials of the upper and lower rigid polyvinyl chloride surface layers needs to be greater than or equal to 65. Preferably, the K-value of the polyvinyl chloride resin in the raw materials of the upper and lower rigid polyvinyl chloride surface layers is 67, the heat stabilizer is an organotin stabilizer, and the impact modifier is a chlorinated polyethylene (CPE) impact modifier.

[0021] This embodiment of the pipe repair profile based on co-extrusion composite process uses the same specific formulation raw materials for both the upper and lower rigid PVC surface layers. PVC resin provides high strength and rigidity to the profile surface, ensuring its load-bearing capacity; heat stabilizers inhibit thermal degradation and discoloration during high-temperature extrusion, ensuring the profile's processing stability and long-term heat aging resistance; calcium carbonate improves surface hardness, rigidity, and dimensional stability while reducing raw material usage; impact modifiers significantly enhance the surface's toughness and impact resistance, preventing brittle cracking under construction disturbances or ground subsidence; acrylate processing aids promote uniform plasticization of PVC, improving surface gloss and extrusion molding stability; titanium dioxide not only gives the profile a white appearance but also absorbs ultraviolet rays, significantly improving the profile surface's weather resistance, anti-aging properties, and anti-yellowing performance. The synergistic effect of the above components gives the upper and lower rigid PVC surface layers comprehensive properties such as high hardness, high strength, high impact resistance, and wear and weather resistance. They can bear the main circumferential stress and load-bearing function in pipeline repair, enhance the structural integrity of the inner liner, extend its service life, and meet the long-term safe use requirements of pipeline repair projects.

[0022] In Example 4, the raw materials for the upper rigid PVC surface layer and the lower rigid PVC surface layer each independently comprise: 100 parts of the PVC resin, 2-4 parts of the heat stabilizer, 10-20 parts of the calcium carbonate, 4-8 parts of the impact modifier, 1-3 parts of the acrylate processing aid, and 3-5 parts of the titanium dioxide.

[0023] In this embodiment, preferably, the heat stabilizer in both the upper and lower rigid PVC surface layers is 3 parts, the calcium carbonate is 15 parts, the impact modifier is 6 parts, the acrylate processing aid is 2 parts, and the titanium dioxide is 4 parts.

[0024] The pipe repair profile based on co-extrusion composite process in this embodiment achieves an optimal balance between mechanical properties (such as strength, hardness and impact resistance), processing properties (such as plasticity, flowability and surface quality), and weather resistance (such as UV resistance, aging resistance and yellowing resistance) of the upper and lower rigid PVC surface layers by optimizing the proportion range of each component, thus meeting the long-term safe use requirements of pipe repair projects.

[0025] In Example 5, the raw materials of the intermediate foamed core layer include: the polyvinyl chloride resin, the foaming agent, the heat stabilizer, the acrylate foaming regulator, the calcium carbonate, the fumed silica, and expandable microspheres.

[0026] Among them, foaming agents refer to substances that can decompose or vaporize to produce gas during processing (such as chemical or physical foaming agents), used to form a cell structure in polyvinyl chloride resin to reduce the overall density of the profile and improve its toughness and sound absorption performance. Acrylic foaming regulators are processing aids specifically used for polyvinyl chloride foaming (such as copolymers of methyl methacrylate and butyl acrylate), used to control the foaming ratio, cell size and uniformity, maintain cell stability, prevent cell merging or collapse, and improve the strength, toughness, and closed-cell rate of the foamed core layer. Fumed silica refers to ultrafine amorphous silica powder (nanoscale reinforcing filler), used to increase melt viscosity, stabilize cells, prevent bubble rupture and merging, and enhance the mechanical strength, heat resistance, and deformation resistance of the foamed core layer. Expandable microspheres are tiny spheres (physical foaming agents) encapsulated in a thermoplastic polymer shell containing a low-boiling-point hydrocarbon liquid, used to assist foaming, refine cell structure, improve foaming uniformity, and enhance the impact resistance and sound damping performance of the foamed layer.

[0027] In this embodiment, preferably, the K value (viscosity constant) of the polyvinyl chloride resin in the raw material of the middle foamed core layer is 58-62, and the foaming agent is a mixture of azodicarbonamide foaming agent and sodium bicarbonate in a mass ratio of 1:2.5.

[0028] This embodiment of the pipe repair profile based on co-extrusion composite process uses a specific formulation of raw materials for the middle foamed core layer. Polyvinyl chloride resin ensures the basic strength and molding stability of the foamed core layer; the foaming agent decomposes upon heating to release gas, forming a foamed structure, reducing the overall density of the profile and improving its overall toughness; the heat stabilizer inhibits thermal degradation and discoloration during the foaming process, ensuring the stability of the foaming molding; the acrylate foaming regulator precisely controls the foaming ratio, refines the cells, prevents cell merging or collapse, and improves the uniformity and closed-cell rate of the cells; calcium carbonate improves the dimensional stability and distribution uniformity of the cells while reducing the amount of raw materials used; fumed silica increases the viscosity of the melt, stabilizes the cell structure, prevents cell merging or collapse, and enhances the mechanical properties of the foamed core layer; expandable microspheres expand upon heating to form an independent closed-cell structure with a high closed-cell rate, further refining the cells, improving the uniformity of foaming, and significantly enhancing the energy absorption capacity and sound damping performance of the foamed core layer. The synergistic effect of the above components enables the intermediate foamed core layer to possess comprehensive properties such as low density, high toughness, high impact resistance, and excellent sound absorption and noise reduction performance. In pipeline repair, it effectively absorbs external impact energy and blocks the propagation of water flow noise, better meeting the engineering needs of pipeline repair under complex working conditions.

[0029] In Example 6, the raw materials of the intermediate foamed core layer include: 100 parts of the polyvinyl chloride resin, 1.5 to 3.5 parts of the foaming agent, 1.5 to 2.5 parts of the heat stabilizer, 8 to 15 parts of the acrylate foaming modifier, 5 to 10 parts of the calcium carbonate, 1 to 3 parts of the fumed silica, and 3 to 8 parts of the expandable microspheres.

[0030] In this embodiment, preferably, the raw materials of the intermediate foamed core layer contain 100 parts of polyvinyl chloride resin, 1.5-3.5 parts of foaming agent, 1.5-2.5 parts of heat stabilizer, 8-15 parts of acrylate foaming regulator, 5-10 parts of calcium carbonate, 1-3 parts of fumed silica, and 3-8 parts of expandable microspheres.

[0031] The pipe repair profile based on co-extrusion composite process in this embodiment achieves an optimal balance between foaming performance (such as foaming ratio, density and cell structure), mechanical properties (such as toughness, impact resistance and energy absorption capacity) and acoustic properties (such as noise reduction effect and sound damping characteristics) in the middle foam core layer by optimizing the proportion range of each component. This results in a synergistic improvement in lightweight, high impact resistance and low noise, better meeting the long-term use requirements of pipe repair projects under complex working conditions.

[0032] In Example 7, the upper rigid PVC surface layer and the lower rigid PVC surface layer each independently have Shore hardness performance parameters, Vicat softening temperature performance parameters, and tensile yield strength performance parameters.

[0033] Among them, Shore hardness is an indicator used to measure the surface hardness and resistance to localized indentation of elastic materials such as plastics and rubber, and is divided into two categories: Shore A (soft) and Shore D (hard). Vicat softening temperature is the temperature at which a material softens to a specified amount of deformation under a specified load, used to characterize the heat deformation resistance of plastic materials. Tensile yield strength is the critical stress value at which a material transitions from elastic deformation to plastic deformation in a uniaxial tensile test, used to reflect the material's load-bearing capacity and structural strength; the test standard is usually ASTM D638 or GB / T1040.

[0034] In this embodiment, the Shore hardness parameter is Shore D. The test standard for tensile yield strength performance parameters is GB / T1040.2-2022.

[0035] This embodiment of the pipe repair profile based on co-extrusion composite technology, by limiting three key performance parameters—Shore hardness, Vicat softening temperature, and tensile yield strength—ensures that both the upper and lower rigid PVC surface layers possess high hardness, high heat resistance, and high structural strength simultaneously. The Shore hardness parameter ensures sufficient hardness and wear resistance for the profile surface layer, preventing scratches and deformation during construction and use; the Vicat softening temperature parameter ensures that the profile surface layer is not easily softened or deformed in high-temperature environments, maintaining dimensional stability; and the tensile yield strength parameter ensures that the profile surface layer possesses excellent load-bearing capacity, capable of withstanding the main circumferential stresses in pipe repair, thus improving the overall structural stability of the inner liner.

[0036] In Example 8, the Shore hardness of the upper rigid PVC surface layer and the lower rigid PVC surface layer are both 75-85, the Vicat softening temperature is both greater than or equal to 80°C, and the tensile yield strength is both greater than or equal to 45 MPa.

[0037] In this embodiment, preferably, the Shore hardness of both the upper and lower rigid PVC surface layers is 75-85, the Vicat softening temperature is greater than or equal to 80°C, and the tensile yield strength is greater than or equal to 45MPa.

[0038] The pipe repair profile based on co-extrusion composite process in this embodiment achieves an optimal balance between rigidity, heat resistance and mechanical strength by quantifying and limiting the Shore hardness, Vicat softening temperature and tensile yield strength performance parameters of the upper and lower rigid PVC surface layers. This effectively improves the stability and durability of the profile structure, extends the service life of the profile, and meets the long-term safe and reliable operation requirements of pipeline repair projects.

[0039] In Example 9, the foaming ratio of the intermediate foamed core layer is 1.8 to 2.5 times.

[0040] Among them, the foaming ratio refers to the ratio of the volume of the foamed material to the volume of the same mass of material before foaming (or before foaming), which can also be equivalent to the density ratio and is used to measure the degree of foaming of plastics.

[0041] In this embodiment, preferably, the foaming ratio of the middle foam core layer is 1.8 to 2.5 times.

[0042] In this embodiment, as Figure 3 The diagram shown is a schematic of the cell structure of the middle foam core layer.

[0043] The pipe repair profile based on co-extrusion composite process in this embodiment can precisely control the degree of plastic foaming by limiting the optimal foaming ratio range for the pipe repair profile. This avoids the poor lightweight effect, insufficient impact resistance, and insufficient sound absorption and noise reduction performance caused by too low a foaming ratio, while also preventing the loose and easily collapsed cells caused by too high a foaming ratio. This improves the overall mechanical strength of the profile and meets the long-term safe use requirements of pipe repair projects under complex working conditions.

[0044] In Example 10, the density of the intermediate foamed core layer is 0.6 g / cm³. 3 -0.9g / cm 3 .

[0045] In this embodiment, preferably, the density of the intermediate foamed core layer is 0.8 g / cm³. 3 .

[0046] The pipe repair profile based on co-extrusion composite process in this embodiment achieves the optimal balance between lightweight and mechanical properties by limiting the optimal density range of the intermediate foamed core layer of the pipe repair profile. This avoids insufficient rigidity and compressive strength caused by excessively low density, while also preventing insignificant foaming effect, poor lightweight effect, and insufficient impact resistance, cushioning, and sound absorption performance caused by excessively high density. This meets the long-term safe use requirements of pipe repair projects under complex working conditions.

[0047] In Example 11, when the total thickness of the profile base plate is 3mm, the thickness of the upper and lower rigid PVC surface layers is 0.75mm, the thickness of the middle foam core layer is 1.5mm, the density of the middle foam core layer is 0.81g / cm³, and the foaming ratio is 2.1 times.

[0048] The tensile yield strength of the profile base plate was tested according to the testing standard GB / T1040.2-2022, and the measured tensile yield strength was 38 MPa, which is 95% of that of a pure solid rigid PVC profile of the same specification. The impact energy absorption capacity of the profile base plate was tested according to the testing standard GB / T1043.1, and the measured notched impact strength of a simply supported beam at 23℃ was 50.6 kJ / m², which is 2.1 times that of a pure solid rigid PVC profile of the same specification. The sound pressure level of the profile base plate was tested according to the testing standard GB / T3222.2-2022, and the measured sound pressure level was 62 dB(A), which is 9.2 dB(A) lower than that of a pure solid rigid PVC profile of the same specification.

[0049] In Example 12, when the total thickness of the profile base plate is 3mm, the thickness of the upper and lower rigid PVC surface layers is 0.60mm, the thickness of the middle foam core layer is 1.8mm, and the density of the middle foam core layer is 0.71g / cm³.

[0050] The tensile yield strength of the profile base plate was tested according to the testing standard GB / T1040.2-2022, and the measured tensile yield strength was 36 MPa, which is 90% of that of a pure solid rigid PVC profile of the same specification. The impact energy absorption capacity of the profile base plate was tested according to the testing standard GB / T1043.1, and the measured notched impact strength of a simply supported beam at 23℃ was 60 kJ / m², which is 2.49 times that of a pure solid rigid PVC profile of the same specification. The sound pressure level of the profile base plate was tested according to the testing standard GB / T3222.2-2022, and the measured sound pressure level was 60 dB(A), which is 10.5 dB(A) lower than that of a pure solid rigid PVC profile of the same specification.

[0051] In the comparative example, the total thickness of the solid rigid PVC profile base plate is 3mm.

[0052] The tensile yield strength of the solid rigid PVC profile base plate was tested according to the testing standard GB / T1040.2-2022, and the measured tensile yield strength was 40 MPa. The impact energy absorption capacity of the solid rigid PVC profile base plate was tested according to the testing standard GB / T1043.1, and the measured notched impact strength of the simply supported beam at 23℃ was 24.1 kJ / m². The sound pressure level of the profile base plate was tested according to the testing standard GB / T3222.2-2022, and the measured sound pressure level was 71.2 dB(A).

[0053] Compared with Example 11, the pipe repair profile based on co-extrusion composite process of the present invention shows a 111% increase in notched impact strength of simply supported beams at 23°C, a 5% decrease in tensile yield strength, and a 9.2 dB(A) decrease in sound pressure level. This demonstrates that the pipe repair profile based on co-extrusion composite process of the present invention has significant effects in improving impact resistance, maintaining yield strength, and reducing noise.

[0054] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0055] While specific embodiments of the invention have been described in detail by way of example, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should also understand that various modifications can be made to the embodiments without departing from the scope and spirit of the invention. The scope of this invention is defined by the appended claims.

Claims

1. A pipe repair profile based on co-extrusion composite process, characterized in that, The pipe repair profile based on co-extrusion composite process includes a profile base plate formed by co-extrusion composite process, the profile base plate including an upper rigid PVC surface layer, an intermediate foamed core layer and a lower rigid PVC surface layer.

2. The pipe repair profile based on co-extrusion composite process according to claim 1, characterized in that, The profile base plate comprises an extruded profile with a three-layer co-extruded composite structure obtained by using three extruders to plasticize the raw materials of the upper rigid PVC surface layer, the middle foamed core layer, and the lower rigid PVC surface layer, and then simultaneously extruding them into a three-layer co-extrusion die for molding.

3. The pipe repair profile based on co-extrusion composite process according to claim 1, characterized in that, The raw materials for the upper rigid PVC surface layer and the lower rigid PVC surface layer each independently include: PVC resin, heat stabilizer, calcium carbonate, impact modifier, acrylate processing aid, and titanium dioxide.

4. The pipe repair profile based on co-extrusion composite process according to claim 4, characterized in that, The raw materials for the upper rigid PVC surface layer and the lower rigid PVC surface layer each independently include: 100 parts of the PVC resin, 2-4 parts of the heat stabilizer, 10-20 parts of the calcium carbonate, 4-8 parts of the impact modifier, 1-3 parts of the acrylate processing aid, and 3-5 parts of the titanium dioxide.

5. The pipe repair profile based on co-extrusion composite process according to claim 1, characterized in that, The raw materials for the intermediate foamed core layer include: the polyvinyl chloride resin, the foaming agent, the heat stabilizer, the acrylate foaming regulator, the calcium carbonate, the fumed silica, and expandable microspheres.

6. The pipe repair profile based on co-extrusion composite process according to claim 5, characterized in that, The raw materials of the intermediate foamed core layer include: 100 parts of the polyvinyl chloride resin, 1.5-3.5 parts of the foaming agent, 1.5-2.5 parts of the heat stabilizer, 8-15 parts of the acrylate foaming regulator, 5-10 parts of the calcium carbonate, 1-3 parts of the fumed silica, and 3-8 parts of the expandable microspheres.

7. The pipe repair profile based on co-extrusion composite process according to claim 1, characterized in that, The upper rigid PVC surface layer and the lower rigid PVC surface layer each independently possess Shore hardness performance parameters, Vicat softening temperature performance parameters, and tensile yield strength performance parameters.

8. The pipe repair profile based on co-extrusion composite process according to claim 7, characterized in that, The Shore hardness of both the upper and lower rigid PVC surface layers is 75-85, the Vicat softening temperature is greater than or equal to 80℃, and the tensile yield strength is greater than or equal to 45MPa.

9. The pipe repair profile based on co-extrusion composite process according to claim 1, characterized in that, The foaming ratio of the intermediate foam core layer is 1.8 to 2.5 times.

10. The pipe repair profile based on co-extrusion composite process according to claim 1, characterized in that, The density of the intermediate foamed core layer is 0.6 g / cm³. 3 -0.9g / cm 3 .

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