JPS5926453B2 - Method for closing holes in resin pipes in which holes are arranged in the tube wall in the tube axis direction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for closing holes in a resin tube in which holes are arranged in parallel in the tube wall in the tube axis direction.

By making the walls of resin pipes such as hard vinyl chloride resin pipes relatively thick and arranging many holes in parallel in the pipe axis direction, we aim to reduce the weight of the pipes and improve their strength against flat loads. Attempts have been made to reduce deformation due to stress such as earth pressure.

A method and apparatus for manufacturing such resin pipes were disclosed in Japanese Patent Application Laid-Open No. 52
This is proposed in the publication No.-89170. The resin tube manufactured by this method and apparatus has holes in the tube axis arranged in parallel on the tube wall that continuously communicate with both end walls of the tube. In the method of enlarging the diameter to form a pipe socket, inserting the unexpanded end of another pipe into this and connecting with adhesive, a seal ring, etc., the hole in the pipe wall communicates with the inside and outside of the pipe 5. There is a drawback that fluid leaks and cannot be used as is. Therefore, for example,
In Publication No. 52222, it is proposed to close the hole in the tube wall using a separate closing member, or to press the hole by heating the tube end and pressing it against a mold to block the hole by dipping. has been done. However, if a closing member is used, the hole may not be completely sealed, or the closing member may come off, resulting in insufficient damage, and if the end of the tube is pressed, the end of the resin tube may not be heated as it is. and press it into the mold, so 15
The joint partition wall of the resin pipe becomes an obstacle when pressing, and is difficult to close. Therefore, in the above-mentioned publication, the mold is rotated and pressed to twist the joint partition wall and press the inner and outer walls against each other for sealing, but operations such as rotating the mold are cumbersome. 20 This invention was made in view of the above points, and its gist is that the pipe wall is made up of inner and outer walls and a joint partition wall that connects the inner and outer walls in the pipe axis direction, and that the pipe wall is lined with through holes in the pipe axis direction. A heat-foamable material is put into the through-hole portion of the resin pipe provided, and the heat-foamable material is heated to foam25.Through holes in the pipe axis direction are arranged in parallel on the pipe wall. It consists in a method of closing a hole in a resin pipe.

Next, the present invention will be explained with reference to embodiments shown in the drawings.

Reference numeral 1 is made of a resin pipe, and the outer wall 11, the inner wall 12, and the connecting partition walls 13, 13 in the pipe axis direction that connect these 30 walls are connected.
are integrally provided with through holes 14, 14 in the tube axis direction in the tube wall.
... are arranged side by side.

This resin tube 1 is obtained by continuously extruding a tube by extrusion molding and cutting it into a predetermined length.

35 Insert the rod-shaped body 2 made of a heat-foamable material into the through holes 14, 14, . . . at the ends of the resin tube 1.

As the heat-foamable material, one that is substantially impermeable to water after foaming and foams at a temperature that does not damage the resin pipe 1 is preferably used. An example of the heat-foamable material is a relatively low-foaming resin composition of vinyl chloride resin, for example, 40 to 10 parts of dioctyl phthalate (DOP) as a plasticizer to 100 parts by weight of polyvinyl chloride.
0 parts by weight, 0.5 parts of azodicarbonamide as a blowing agent
~5.0 parts by weight, 1 to 3 parts by weight of zinc oxide and zinc stearate as foaming aids, plus the required amount of stabilizer. The resin pipe 1 is molded into a rod shape in its unfoamed state and used for the through holes 14, 14,
It is preferable because it can be easily put into... Next, the through hole 1 at the end of the resin pipe 1
The rod-shaped body 2 placed in 4, 14... is heated and foamed.

During foaming, the volume naturally expands, and the through holes 14, 14, . . . where the rod-shaped body 2 is inserted are filled with the foam 2'. As the heating and foaming means, it is extremely convenient to use the process of heating and softening the end of the resin tube 1 and expanding the diameter of this portion to form a tube socket, without requiring any special heating and foaming means. The result obtained in this way is shown in FIG. The pipe socket a is not limited to the so-called rubber ring joint type fitted with a sealing ring b as shown in the figure, but may of course be an adhesive type pipe socket that does not use a sealing ring b. be. As mentioned above, this method involves putting a heat-foamable material into the hole in the resin pipe and heating and foaming it, which not only makes it extremely easy to block the hole, but also makes it possible to close the hole in that area. It is definitely occluded by the developing body.

[Brief explanation of the drawing]

Fig. 1 shows an example of a resin pipe whose through hole is to be closed.
The figure is a partially cutaway perspective view of an example of a resin tube whose through holes are closed by the method of the present invention. 1...Resin pipe, 11...Outer wall, 12...Inner wall, 1
3... Bonding partition, 14... Through hole, 2... Heat-foamable material, 2'... Foam.

Claims (1)

[Claims] 1. A heat-foamable material is put into the through-hole portion of a resin tube, which is composed of an inner and outer wall and a joint partition wall in the tube axis direction that connects the inner and outer walls, and in which the tube wall is lined with through holes in the tube axis direction. A method for closing holes in a resin pipe in which holes are arranged in parallel in the tube axis direction in a tube wall, the method comprising heating and foaming a heat-foamable material.