JPH0442119Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a lining material for pipes, and particularly to a lining material suitable for pipes that require heat resistance and chemical resistance.

For example, in an exhaust pipe of a boiler or the like, the exhaust gas is at a high temperature in a portion directly connected to the boiler, and the internal temperature of the exhaust pipe rises to about 200°C. The temperature also decreases as you move toward the end of the exhaust pipe, but as the temperature decreases, the temperature in the exhaust gas decreases.
NOx, SOx, chlorine gas, etc. condense together with water vapor, become highly concentrated acids such as nitric acid, sulfuric acid, and hydrochloric acid, form drains, and adhere to the inner surface of the pipe. Therefore, the exhaust pipe is required to have heat resistance at around 200°C and acid resistance at high temperatures around 70 to 100°C.

Furthermore, there are many applications in which heat resistance and chemical resistance must be provided, such as in organic halide manufacturing plants, salt electrolysis plants, and various inorganic industrial chemical manufacturing plants.

The present invention is suitable for lining these pipes.
The present invention relates to a lining material that has heat resistance and chemical resistance at high temperatures.

Conventional technology As a lining material for conventional pipes,
Those described in Japanese Utility Model Publication No. 21219, Japanese Utility Model Application Publication No. 60-85336, etc. are known. These products are made by forming a covering layer made of synthetic resin (such as polyester elastomer, polyolefin synthetic resin, etc.) on the outer surface of a cylindrical woven fabric made by weaving synthetic fibers (such as polyester synthetic fiber) into a cylindrical shape. This lining material is inserted into the pipe while being turned over by fluid pressure, and is pressed against the inner surface of the pipe by the fluid pressure and adhered to form the lining.

These lining materials are widely used as lining materials for gas pipes, water pipes, oil pipelines, etc.

Problems to be Solved by the Invention However, although these lining materials exhibit sufficient performance at room temperature, their performance deteriorates significantly in high-temperature atmospheres, making them unusable. Since both the fibers and the coating layer of the lining material are thermoplastic, the performance deteriorates significantly near the softening point of the resin, and it cannot be used at all above 200°C. Furthermore, when strongly acidic or alkaline conditions are added to this, it easily deteriorates even at temperatures of 70 to 100 degrees Celsius, and cannot withstand long-term use.

The present invention was developed in view of the above circumstances, and aims to provide a lining material that has both heat resistance and chemical resistance and can be used satisfactorily even under the harsh conditions mentioned above. This is the purpose.

Means for Solving the Problems The pipe lining material of the present invention is produced by weaving threads made of aromatic polyamide synthetic fibers into a cylindrical shape as warp and weft yarns to form a cylindrical woven fabric. On the surface corresponding to the inner surface when the cloth is lined,
It is characterized by forming a coating layer of tetrafluoroethylene-propylene elastomer.

The drawing shows the lining material of the present invention,
A flexible covering layer 2 is formed on the outer surface of the cylindrical woven fabric 1. The tubular woven fabric 1 is made by weaving warp threads 3 and weft threads 4 into a tubular shape, and the warp threads 3 and weft threads 4 are made of aromatic polyamide synthetic fibers.

As the aromatic polyamide synthetic fiber used here, polydiphenylene ether p-phenylene terephthalamide fiber (trade name: Technora, manufactured by Teijin Ltd.) is suitable for the warp yarns 3.
This fiber has excellent acid resistance, alkali resistance, and organic solvent resistance compared to other aromatic polyamide fibers, and is excellent as a warp yarn in the present invention. In addition, it is preferable to use yarns that have been subjected to bulk processing such as taslan processing as the warp yarns 3, and the coating layer 2
Improves adhesion with.

Further, as the weft yarn 4, polymetaphenylene isophthalamide (trade name: Cornex, manufactured by Teijin Ltd.) is suitable. This fiber has particularly excellent heat resistance and has a higher elongation at break (approximately 38%) than other aromatic polyamide fibers. The diameter of the lining material expands due to internal pressure and can be brought into pressure contact with the inner surface of the pipe. Furthermore, this fiber is preferably used as a spun yarn.

Next, for the coating layer 2, a tetrafluoroethylene-propylene elastomer (for example, AFRAS, a product of Japan Synthetic Rubber Co., Ltd.) is used. This elastomer is a copolymer of tetrafluoroethylene and propylene, and the two are substantially alternately arranged. Since the methyl groups in propylene are randomly arranged, it is non-crystalline and has rubber elasticity despite the regular arrangement of the monomers. Furthermore, since propylene units are sandwiched between tetrafluoroethylene units, it is extremely stable thermally and chemically, and has excellent heat resistance and chemical resistance.

This elastomer has a hardness (JIS A) of 80.
Below, Mooney viscosity (ML1+4 (100℃)) 30 to 70
Tensile strength: 100Kg/ ^cm2 or more, elongation at break:
250% or more is desirable. If the hardness is over 80, the lining material will lack flexibility, and the Mooney viscosity will be 70.
If this is the case, the extrusion properties will deteriorate and the adhesiveness to the tubular woven fabric 1 will be poor. In addition, if the Mooney viscosity is less than 30, the adhesive will penetrate excessively deep into the weave of the tubular woven fabric 1 and penetrate to the opposite surface, making the lining material hard and unable to penetrate the weave, making it difficult for the lining material to penetrate. Poor adhesion to pipes.

Further, the appropriate thickness of the coating layer 2 is about 0.5 to 1.5 mm. If the coating layer 2 is too thin, it will cause pinholes, and if it is too thick, the lining material will be hard and difficult to line. Note that when adopting a method of lining the inner surface of the pipe with the lining material by inserting and bonding the lining material while turning it inside out using fluid pressure, a coating layer 2 is applied to the outer surface of the cylindrical woven fabric 1 as shown in the drawing. However, if a method is adopted in which the lining material is directly drawn into the tube and bonded, the covering layer 2 must be formed on the inner surface of the cylindrical woven fabric 1.

Function In the present invention, the aromatic polyamide synthetic fibers constituting the warp 3 and weft 4 of the tubular woven fabric 1 and the tetrafluoroethylene-propylene elastomer constituting the coating layer 2 have heat resistance, and Tetrafluoroethylene-propylene elastomer has excellent chemical resistance, so it has excellent heat and chemical resistance as a lining material and effectively protects pipes. Especially required for boiler exhaust pipes as mentioned above.
It is possible to simultaneously satisfy heat resistance around 200°C and acid resistance and alkali resistance around 70 to 100°C.

In addition, the tetrafluoroethylene-propylene elastomer used as the coating layer 2 is itself amorphous, has rubber elasticity, and is flexible, so it can ensure the flexibility of the lining material. The lining can be lined by inserting the tube into the tube while turning it inside out using fluid pressure.

In general, silicone rubber, fluorocarbon rubber, fluorocarbon resin, etc. are considered as materials that have both heat resistance and chemical resistance, but silicone rubber is insufficient in terms of acid resistance at high temperatures, and fluorocarbon resin has problems in terms of processability and flexibility. As the fluoro rubber, vinylidene fluoride-propylene hexafluoride fluoro rubber (for example, Dupont's product name Viton) is widely used, but the vulcanization system is amine, polyol, or peroxide. Although it depends on the material, it is not possible to satisfy both heat resistance and acid resistance at high temperatures at the same time.

Effects of the invention According to the invention, it is possible to simultaneously satisfy heat resistance and acid resistance at high temperatures as a lining material, and it can be used for boiler exhaust pipes, organic halide manufacturing plants, salt electrolysis plants, and various inorganic industrial chemical manufacturing plants. It is excellent as a lining material for lining pipe systems such as.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the lining material of the present invention, and FIG. 2 is an enlarged cross-sectional view of a portion thereof. 1...Tubular woven fabric, 2...Coating layer, 3...Warp yarn, 4...Weft yarn.

Claims (1)

[Claims for Utility Model Registration] 1. A cylindrical woven fabric 1 is formed by weaving yarns made of aromatic polyamide synthetic fibers as warp 3 and weft 4 into a cylindrical shape, and in the lining state of the cylindrical woven fabric 1. A pipe lining material comprising a coating layer 2 of a tetrafluoroethylene-propylene elastomer formed on a surface corresponding to the inner surface. 2. The warp yarns 3 of the tubular woven fabric 1 are yarns made of polydiphenylene ether p-phenylene terephthalamide synthetic fibers, and the weft yarns 4 are yarns made of polymethaphenylene isophthalamide synthetic fibers. A pipe lining material according to claim 1 of the utility model registration claim. 3. The utility model registration claim 1 or 2, characterized in that the warp 3 of the tubular woven fabric 1 is a bulky yarn, and the weft 4 is a spun yarn. pipe lining material.