Super-slip inner wall polypropylene pipe

Abstract

This utility model relates to the field of power pipe technology and discloses a super-smooth inner wall polypropylene pipe, comprising a polypropylene main body, wherein a co-extruded transition layer and a functional coating are sequentially laminated to the inner wall surface of the polypropylene main body, and the co-extruded transition layer and the polypropylene main body are integrally formed; the functional coating comprises a polytetrafluoroethylene (PTFE) underlayer chemically bonded to the surface of the co-extruded transition layer and a hot-melt lubricating and curing layer coated on the surface of the PTFE underlayer. This solves the problem in the prior art of insufficient inner wall smoothness and high static friction coefficient in polypropylene pipes, resulting in low cable threading efficiency.

Description

Technical Field

[0001] This utility model relates to the field of power pipe technology, and in particular to a super-smooth inner wall polypropylene pipe. Background Technology

[0002] Polypropylene cable conduits are trenchless power conduits made primarily of modified polypropylene. Their installation eliminates the need for extensive dredging, excavation, and road surface damage, making them ideal for use in special locations such as roads, railways, buildings, and riverbeds. Compared to the traditional trenching method, trenchless power conduit installations are more environmentally friendly, avoiding the dust, traffic congestion, and other disturbances caused by traditional construction methods. Furthermore, trenchless power conduits can be laid in areas where excavation is not feasible, such as historical sites, urban areas, crop and farmland protection zones, highways, and rivers.

[0003] Currently, the raw materials for producing polypropylene cable conduits are polypropylene resin aging-resistant masterbatch mixed in a certain proportion. These types of pipes are usually single-walled pipes, which have the following disadvantages: insufficient inner wall smoothness and high static friction coefficient, resulting in low cable threading efficiency. Utility Model Content

[0004] In view of this, the purpose of this utility model is to provide a super-smooth inner wall polypropylene pipe to solve the problem that the inner wall smoothness of the polypropylene pipe in the prior art is insufficient, the static friction coefficient is high, and the cable threading efficiency is low.

[0005] This utility model solves the above-mentioned technical problems through the following technical means: a super-slippery inner wall polypropylene pipe, including a polypropylene main body, wherein a co-extruded transition layer and a functional coating are sequentially laminated on the inner wall surface of the polypropylene main body, and the co-extruded transition layer and the polypropylene main body are integrally formed; the functional coating includes a polytetrafluoroethylene underlayer chemically bonded to the surface of the co-extruded transition layer and a hot melt lubricating curing layer coated on the surface of the polytetrafluoroethylene underlayer.

[0006] Optionally, the co-extruded transition layer has a thickness of 0.05-0.3 mm and is made of maleic anhydride-grafted modified polypropylene. This enhances the interlayer bonding strength.

[0007] Optionally, the co-extruded transition layer contains dispersed nano-silica particles with a particle size of 20-50 nm and a mass fraction of 3-8%. This enhances the rigidity of the transition layer through a filling effect.

[0008] Optionally, the polypropylene main body is made of polypropylene mixed with short glass fiber material.

[0009] Optionally, the material of the hot-melt lubricating curing layer is polyethylene wax. The film formed after melting and spraying and cooling has low surface hardness and low dynamic friction coefficient.

[0010] Optionally, the surface roughness Ra of the hot melt lubricated cured layer is ≤0.8μm.

[0011] Optionally, the outer wall of the polypropylene main pipe is provided with a reinforcing fiber braided layer, and an adhesive layer is provided between the reinforcing fiber braided layer and the polypropylene main pipe body. This further compensates for the overall rigidity of the polypropylene pipe.

[0012] The beneficial effects of this utility model are:

[0013] This invention involves sequentially laminating a co-extruded transition layer and a functional coating onto the inner wall surface of a polypropylene main pipe. The co-extruded transition layer and the polypropylene main pipe are integrally formed, enhancing interlayer bonding. The functional coating comprises a polytetrafluoroethylene (PTFE) underlayer chemically bonded to the surface of the co-extruded transition layer and a hot-melt lubricating and curing layer coated on the surface of the PTFE underlayer. This dual-lubricating coating significantly reduces cable traction resistance compared to ordinary polypropylene pipes. Furthermore, the hot-melt lubricating and curing layer is a soft lubricating layer formed from polyethylene wax, which buffers localized pressure between the cable and the inner pipe wall, reducing scratches on the cable sheath surface. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0015] Among them, 1-polypropylene main body, 2-co-extruded transition layer, 3-functional coating, 31-polytetrafluoroethylene base layer, 32-hot melt lubricating curing layer, 4-adhesive layer, 5-reinforcing fiber braided layer. Detailed Implementation

[0016] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can understand the advantages and effects of this utility model from the content disclosed in this specification. It should be noted that the illustrations provided in the following embodiments are for illustrative purposes only and represent schematic diagrams, not actual pictures. They should not be construed as limiting the utility model. To better illustrate the embodiments of this utility model, some components in the figures may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable that some well-known structures and their descriptions may be omitted in the figures for those skilled in the art.

[0017] In the figures of this utility model embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figure, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe the positional relationship in the figure are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above-mentioned terms can be understood according to the specific circumstances.

[0018] like Figure 1 As shown, this utility model discloses a super-slippery inner wall polypropylene pipe, comprising a polypropylene main body 1, which is made of polypropylene mixed with short glass fiber material. The inner wall surface of the polypropylene main body 1 is sequentially laminated with a co-extruded transition layer 2 and a functional coating 3, and the co-extruded transition layer 2 and the polypropylene main body 1 are integrally formed; the functional coating 3 includes a polytetrafluoroethylene (PTFE) underlayer 31 chemically bonded to the surface of the co-extruded transition layer 2 and a hot-melt lubricating curing layer 32 coated on the surface of the PTFE underlayer 31.

[0019] In this embodiment, to improve the adhesion of the transition layer, the thickness of the co-extruded transition layer 2 is 0.05-0.3 mm and its material is maleic anhydride grafted modified polypropylene. During the co-extrusion molding process with the polypropylene main body 1, the polar groups (such as anhydride groups) in the maleic anhydride grafted modified polypropylene molecular chain form chemical bonds with the polypropylene main body 1. At the same time, the maleic anhydride grafted modified polypropylene and polytetrafluoroethylene can also enhance the bonding force through polar interaction, thereby achieving the purpose of enhancing the interlayer bonding force.

[0020] In this embodiment, nano-silica particles with a particle size of 20-50nm and a mass fraction of 3-8% are dispersed in the co-extruded transition layer 2. The rigidity of the transition layer is improved through the filling effect, thereby reducing the risk of interlayer delamination caused by temperature changes such as thermal expansion and contraction.

[0021] In this embodiment, the hot-melt lubricating curing layer 32 is made of polyethylene wax, which can be formed by hot-melt coating and cooling. The surface roughness Ra of the hot-melt lubricating curing layer 32 is ≤0.8μm. For example, polyethylene wax with a melt index of 200-500g / 10min can be selected. It has short molecular chains, high crystallinity, and a coating thickness range of 5-15μm. The film formed after melting and spraying and cooling has low surface hardness (Shore D hardness ≤40), and the molecular chains are prone to directional slippage during cable traction, thereby significantly reducing the dynamic friction coefficient (μ≤0.08).

[0022] It should be understood that the outer wall of the polypropylene main body 1 is provided with a reinforcing fiber braided layer 5, and an adhesive layer 4 is provided between the reinforcing fiber braided layer 5 and the polypropylene main body 1. The reinforcing fiber braided layer 5 compensates for the overall rigidity of the polypropylene pipe. The adhesive layer 4 and the reinforcing fiber braided layer 5 are common existing technologies, and their specific structures and material composition will not be described in detail.

[0023] The working principle of this utility model is as follows:

[0024] In the production of the pipe of this utility model, the co-extruded transition layer 2 and the polypropylene main body 1 are integrally formed by a double-layer co-extrusion process. After cooling, the surface of the co-extruded transition layer 2 is roughened to give it a certain roughness and increase its specific surface area. Then, the polytetrafluoroethylene underlayer 31 is composited by hot pressing (temperature 120-160℃, pressure 0.5-2MPa). After that, a thin film is sprayed by polyethylene wax melt spraying and cooled to form a hot melt lubricated curing layer 32. Finally, the reinforcing fiber braided layer 5 is connected by an adhesive layer 4.

[0025] Typically, after the power conduit is laid, the cables are pulled in unison. When pulling the cables begins, the functional coating 3 with its double lubrication layer reduces the cable pulling resistance by more than 60%-70% compared to ordinary polypropylene pipes. At the same time, the hot-melt lubrication curing layer 32, a soft lubricating layer formed by polyethylene wax, can buffer the local pressure between the cable and the inner pipe wall, reducing scratches on the cable sheath surface.

[0026] In particular, the polytetrafluoroethylene underlayer 31 and the hot melt lubrication curing layer 32 have natural hydrophobicity to prevent the formation of water film, thereby avoiding the increase in the coefficient of friction caused by lubrication failure, making them very suitable for laying power pipes in humid environments.

[0027] The above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model. Technologies, shapes, and structural parts not described in detail in this utility model are all known technologies.

Claims

1. A super-slippery inner wall polypropylene pipe, comprising a polypropylene main body (1), characterized in that: The inner wall surface of the polypropylene main body (1) is sequentially coated with a co-extruded transition layer (2) and a functional coating (3), and the co-extruded transition layer (2) and the polypropylene main body (1) are integrally formed; the functional coating (3) includes a polytetrafluoroethylene underlayer (31) chemically bonded to the surface of the co-extruded transition layer (2) and a hot melt lubricating curing layer (32) coated on the surface of the polytetrafluoroethylene underlayer (31).

2. The super-smooth inner wall polypropylene pipe according to claim 1, characterized in that: The co-extruded transition layer (2) has a thickness of 0.05-0.3 mm and is made of maleic anhydride grafted modified polypropylene.

3. The super-slippery inner wall polypropylene pipe according to claim 2, characterized in that: The co-extruded transition layer (2) contains nano-silica particles with a particle size of 20-50 nm and a mass fraction of 3-8%.

4. The super-slippery inner wall polypropylene pipe according to claim 1, characterized in that: The polypropylene main body (1) is made of polypropylene mixed with short glass fiber material.

5. The super-smooth inner wall polypropylene pipe according to claim 1, characterized in that: The material of the hot melt lubricating curing layer (32) is polyethylene wax.

6. The super-slippery inner wall polypropylene pipe according to claim 1, characterized in that: The surface roughness Ra of the hot melt lubricated curing layer (32) is ≤0.8μm.

7. The super-slippery inner wall polypropylene pipe according to any one of claims 1-6, characterized in that: The outer wall of the polypropylene main body (1) is provided with a reinforcing fiber braided layer (5), and an adhesive layer (4) is provided between the reinforcing fiber braided layer (5) and the polypropylene main body (1).

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