JPH045580Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a lining material for lining existing water pipes that are mainly buried underground for the purpose of repair or reinforcement. In recent years, in order to repair existing water pipes that have deteriorated due to rust or corrosion, lining them with flexible cylindrical lining materials has been practiced. As a lining method for this purpose, which has recently attracted particular attention, a flexible lining material is inserted into the pipe while turning the inside and outside surfaces inside out using pressure fluid, and at the same time, the lining material is crimped onto the inner surface of the pipe by the fluid pressure. There is a so-called inverted lining construction method in which the lining is glued together. This method is easy to insert the lining material into the pipe, can be constructed in a short time, and can be carried out regardless of the length of the pipe or the inner diameter of the pipe, and can also be applied to curved pipes. This method has many advantages, such as being easily applicable. The lining material used in this inverted lining method is flexible, airtight, and requires considerable strength in the vertical and horizontal directions, so it is usually made of synthetic resin on the outer surface of the cylindrical fabric. A material with a coating layer formed thereon is used. The cylindrical fabric layer contains an adhesive and is bonded to the inner surface of the pipe by the adhesive, and the coating layer prevents fluid leakage and reduces fluid friction to ensure smooth fluid flow. I'm starting to do that. Furthermore, the synthetic resin used for the coating layer of this lining material is one that is flexible, has appropriate elasticity and strength, and has excellent heat resistance, abrasion resistance, and water resistance. However, when this lining material is used for water pipes, the synthetic resin of the coating layer is required to be safe in terms of water quality. The materials to be used for water pipes are determined by the standards of the Japan Water Works Association (JWWA), and the coating layer of the lining material is required to conform to these standards. Therefore, in this JWWA standard, the lining material is considered to be similar to the inner surface coating of water pipes with tar epoxy resin paint, and the "Tar epoxy resin paint coating method for water pipes" (K-115) is applied. , the following conditions are required to be met. 1 Turbidity must be 0.5 degrees or less. 2 Chromaticity must be 1 degree or less. 3. Potassium permanganate consumption shall be 2 ppm or less. 4. The reduction in residual chlorine shall be 0.7ppm or less. 5 Phenols shall be 0.005ppm or less. 6. No amines detected. 7 Cyan is not detected. 8. No abnormal odor or taste. Polyurethane elastic resins, polyester elastomers, etc., which are used as coating layers for lining materials for general gas pipes and other pipelines, do not comply with the above standards and cannot be used as coating layers for lining materials for water pipes. . The applicant tested various synthetic resins to determine whether they met the above standards, and found that the only synthetic resins that met the standards were polyolefin-based synthetic resins and fluorine-based resins. . Of these, fluorine-based resins are extremely expensive and have poor extrusion properties, so they are not suitable for the purpose of the present invention, and are effectively limited to polyolefin-based synthetic resins. Polyolefin-based synthetic resins include high-density polyethylene, medium-density polyethylene, low-density polyethylene, polypropylene, and polybutene.
High-density polyethylene and medium-density polyethylene lack flexibility, and low-density polyethylene has poor stress cracking resistance. Further, polypropylene has poor flexibility, and polybutene has poor heat resistance and whitening occurs at the folded portion, which is not preferable. The present invention was devised in view of the above circumstances, and aims to provide a lining material that does not affect water quality and is capable of inversion lining. It uses low-density polyethylene. Linear low-density polyethylene is a polyolefin whose main component is ethylene, which is obtained by copolymerizing ethylene and α-olefin.In terms of density, it belongs to the low-density polyethylene region, and in terms of molecular structure, it has long chain branches. It has a structure similar to that of linear high-density polyethylene, with almost no This linear low-density polyethylene has both the flexibility of low-density polyethylene and the wear resistance and stress cracking resistance of high-density polyethylene, and is suitable for the purpose of the present invention. The basic properties of this linear low density polyethylene include tensile strength of about 330Kgf/ ^cm2 , elongation of about 740%, and melting point of 120℃.
It has excellent stress cracking resistance of over 1000 hours. Note that the stress cracking resistance mentioned here is measured by the test method specified as "Constant strain environmental stress cracking test" in JIS-K-6760 "Polyethylene test method". It represents the time it takes for cracks to occur when a material is placed under a certain strain in a predetermined environment, and is one of the most important characteristics, especially for lining materials for water pipes. Therefore, in the lining material used in the above-mentioned inverted lining method, the present invention uses yarns made of a mixture of filament yarns and spun yarns of synthetic fibers.
A coating of linear low density polyethylene resin is formed on the outer surface of a cylindrical fabric used for at least one of the warp yarns or the weft yarns, and the linear low density polyethylene resin is allowed to penetrate between the grains of the cylindrical fabric. It is characterized by: The linear low density polyethylene used in the present invention preferably has a Shore D hardness in the range of 48 to 53, particularly about 50. Also, the appropriate density is around 0.92g. Furthermore, regarding the MFR value (JIS-K-6760) related to extrusion characteristics, a lower value is desirable, and about 2.2 g/10 minutes is preferable. this is
This is because as the MFR value increases, molecular orientation tends to occur and stress cracking resistance deteriorates.
The thickness of the coating layer of the lining material is suitably 0.4 to 1.5 mm. If the thickness is too thin, pinholes are likely to occur, and if it is too thick, it will be difficult to turn the lining material over. Examples of the present invention will be shown below. FIG. 1 shows the lining material of the present invention, in which the aforementioned linear low-density polyethylene coating layer 2 is formed on the outer surface of a cylindrical fabric 1. The tubular fabric 1 is made by weaving warp threads 3 and weft threads 4 made of fiber into a tubular shape.
The weft yarn 4 is made of polyester synthetic fiber yarn. Furthermore, the lining material of the conduit of this invention was
A specific example will be explained using a lining material for a pipe of mmΦ as an example. The cylindrical fabric 1 has a warp thread 3 of 1100
Using 638 threads made by twisting four denier polyester filament threads, two threads are tied together.
The weft thread 4 is made by twisting two 1100 denier polyester filament threads and four 20 count spun polyester threads at a twist rate of 2.0 to 2.5 times/inch, resulting in 62 threads per 10 cm. It is woven into a cylindrical shape. Generally, in polyolefin synthetic resins,
Since the resin itself does not have adhesive properties and has a high melt viscosity during extrusion, it has poor adhesive properties with the tubular fabric 1. Therefore, in the present invention, a spun yarn with a lot of fuzz is used for the tubular fabric 1, and in order to improve the adhesion between the coating layer 2 and the tubular fabric 1, as shown in FIG. The linear low-density polyethylene of the coating layer 2 is allowed to penetrate between the grains of the fabric. If the tubular fabric 1 is composed of only spun yarns,
However, spun yarn lacks yarn strength, and in order to maintain strength and pressure resistance as a lining material, a large amount of thick yarn must be used, which is preferable. do not have. Therefore, in the present invention, by mixing and twisting filament yarn with strong yarn strength and spun yarn with excellent adhesiveness to polyethylene, it is possible to obtain a lining material with excellent strength and pressure resistance as well as adhesive strength. It can be done. In the above embodiment, spun yarn was used as the weft yarn 4 of the tubular fabric 1, but it may also be used as the warp yarn 3, and both the warp yarn 3 and the weft yarn 4 may be a mixed twisted yarn of filament yarn and spun yarn. You can also do that. For example, in a lining material for a large-diameter pipe of 400 cm or more, it is preferable to use a mixed twisted yarn of filament yarn and spun yarn for the warp yarn 3, and to configure the weft yarn 4 only from filament yarn. This is it [table]

[Brief explanation of drawings]

Figure 1 is a perspective view showing the lining material of the present invention, Figure 2 is a perspective view showing the lining material of the present invention;
The figure is an enlarged cross-sectional view of a part thereof. 1...Tubular fabric, 2...Coating layer, 3...Warp yarn, 4...Weft yarn.

Claims (1)

[Scope of utility model registration request] A method for lining pipes in which a flexible lining material is inserted from one end of the pipe to the other end while being turned over by fluid pressure, and at the same time the lining material is bonded to the inner surface of the pipe by the fluid pressure. In the lining material used, a linear low-density polyethylene resin is applied to the outer surface of a cylindrical fabric in which at least one of the warp or weft yarns is a mixture of filament yarns of synthetic fibers and spun yarns of synthetic fibers. A lining material for water pipes, characterized in that a coating layer is formed and the linear low-density polyethylene resin is infiltrated between the grains of the cylindrical fabric.