JPH0720496U - Polyethylene sleeve method sleeve - Google Patents

Abstract

(57) [Summary] [Purpose] It is an object of the present invention to provide a sleeve for a polyethylene sleeve construction method, which can prevent not only moisture but also oxygen from permeating, and which enables more complete corrosion protection. [Structure] A laminated sheet obtained by laminating a film 2 having a low oxygen permeability such as a polyvinyl chloride film or a vinylidene chloride film on a polyethylene film 1 is formed into a tubular shape 3.
It is formed by molding to reduce the moisture and oxygen permeability to achieve corrosion protection of the outer surface of the metal tube.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a sleeve for a polyethylene sleeve method.

[0002]

[Prior art]

 When burying metal pipes such as cast iron pipes in the ground, a sleeve is coated on the outer surface of the pipe to protect the outer surface from soil, groundwater and other corrosion factors, and this is buried in the ground. It has been known. In this polyethylene sleeve construction method, the outer circumference of the pipe is completely covered with a polyethylene sleeve, so the outer surface of the pipe is completely shielded from corrosion-causing substances such as soil and groundwater. It has an advantage of imparting sex.

[0003]

[Problems of conventional technology]

However, although the polyethylene has a fairly low water molecule permeability of 0.20 g / day / 100 in ² / mil, the oxygen molecule permeability is, for example, 480 cc / day / mil compared to 0.0 cc / day / 100 in ² / mil of rigid PVC. Since it is as high as 100 in ² / mil, there is a problem that the outer surface of the tube is oxidatively corroded by the permeated oxygen even though the water can be completely blocked. However, the water permeation rate of the above rigid PVC is 0.60 g / day / 100 in ² / mil, which is slightly higher than that of polyethylene, so that the rigid PVC is not suitable as a covering sleeve for a buried pipe.

[0004]

[Problems to be solved by the device]

 The present invention has been made in view of the above problems, and an object thereof is to provide a sleeve for a polyethylene sleeve method in which not only moisture but also oxygen is prevented from being permeated so that corrosion can be more completely prevented.

[0005]

[Means for Solving the Problems]

 That is, the polyethylene sleeve method sleeve of the present invention is characterized in that a laminated sheet obtained by laminating a polyethylene film 1 and a film 2 having a low oxygen permeability of a polyvinyl chloride film or a vinylidene chloride film is formed into a tubular shape. And what to do.

[0006]

[Action]

 As mentioned above, polyethylene has a very low water permeability and is suitable as a raw material for sleeves for pipe coating, but it has another difficulty in preventing oxidative corrosion of pipes because it has oxygen permeability. On the other hand, a polyvinyl chloride film or a vinylidene chloride film has an insufficient moisture permeability, but has an oxygen permeability of almost 0, which is superior to polyethylene. Therefore, in order to bring out the advantages of both, these two are laminated and integrated into a sleeve material. Therefore, polyethylene blocks water and polyvinyl chloride film or vinylidene chloride film blocks oxygen, and synergistically prevents corrosion of pipes.

[0007]

【Example】

 Next, an embodiment of this invention will be described. FIG. 1 is an enlarged cross-sectional view of an essential part of an embodiment of the present invention, and FIG. 2 is a perspective view of the embodiment.

Example 1 A polyvinyl chloride film 2 having the same thickness was laminated on the surface of a polyethylene film 1 having a thickness of 10 μm, and heat fusion was performed to integrate the both, and a sleeve was formed as shown in FIG. 3 was formed. Example 2 A sleeve was formed in the same manner as in Example 1 except that a vinylidene chloride film was used instead of the polyvinyl chloride film 2 of Example 1.

Comparative Example 1 A sleeve made of a polyethylene film having a thickness of 20 μm was prepared. Comparative Example 2 A sleeve made of a polyvinyl chloride film having a thickness of 20 μm was prepared.

The water permeability and the oxygen permeability of the above Examples 1 and 2 and Comparative Examples 1 and 2 were tested, and the results shown in Table 1 were obtained.

[0011]

[Table 1]

As is clear from Table 1, Examples 1 and 2 of the present invention have much lower moisture permeability and oxygen permeability than Comparative Examples 1 and 2 and are excellent as a protective skin film in the polyethylene sleeve method. found.

[0013]

[Effect of device]

 As explained above, this invention has an oxygen transmission rate of 0 compared with the conventional polyethylene sleeve, so that not only water permeation but also corrosion of the outer surface of the pipe due to oxygen permeation is effectively prevented, and therefore, the long-term buried metal pipe can be protected. Corrosion can be prevented.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part of an embodiment of the present invention.

FIG. 2 is a perspective view of an embodiment of the present invention.

[Explanation of symbols]

 1 ... Polyethylene film 2 ... Film with low oxygen transmission rate 3 ... Sleeve

Claims (2)

[Scope of utility model registration request] 1. A sleeve for a polyethylene sleeve method, wherein a laminated sheet formed by laminating a film 2 having a low oxygen permeability on a polyethylene film 1 is formed into a cylindrical shape 3. 2. The sleeve for a polyethylene sleeve construction method according to claim 1, wherein the film 2 having a low oxygen transmission rate is a polyvinyl chloride film or a vinylidene chloride film.