JP2538788B2 - Manufacturing method of synthetic resin corrugated tube - Google Patents

Description

The present invention relates to a method for producing a synthetic resin corrugated pipe used as a water supply / drainage pipe for agricultural and civil engineering, a water supply / drainage pipe for industrial use, and the like, more specifically, pressure resistance, running water and The present invention relates to a method for producing a synthetic resin corrugated pipe which is capable of continuously and efficiently molding a large-diameter synthetic resin corrugated pipe excellent in watertightness near a construction site.

[Conventional technology]

Conventionally, as a method of manufacturing a corrugated pipe made of synthetic resin of this kind, a sheet is formed on a rotary shaft body such as a virtual cylindrical rotary shaft body as found in Japanese Patent Publication No. 50-33112 and Japanese Patent Publication No. 56-89531. A method of manufacturing a synthetic resin corrugated pipe having spiral irregularities on the surface by spirally winding a band-shaped body formed in a tubular shape or a tube shape and a core material, and fusing them together is known. Has been.

[Problems to be solved by the invention]

However, the above-mentioned manufacturing method is extruded from the pressing machine, and it is difficult to mold near the construction site because the band-shaped body which is still in a semi-molten state is wound on the rotating shaft to be manufactured. , The bulky tube that has been molded in the factory must be transported to the construction site, which significantly increases the transportation cost, and further spirally winds the strip on the upper surface of the virtual cylindrical rotary shaft. At that time, a thin strip was used because a one-leaf strip was used, and in addition, since the first wound strip and the later wound strip overlap each other at their sides to form a tubular body. In this case, since the width of the above-mentioned polymerized portion must be widened in order to maintain a specific thickness, the productivity is remarkably reduced, and when a thick band is used, the moldability of the band is better than that of the band. If you can't get a uniform thickness Ride no, there is a problem such as a step is formed in the overlapping portion.

The present invention was invented to eliminate the drawbacks of the above-mentioned conventional methods, and a construction site for a large-diameter synthetic resin corrugated pipe having a substantially smooth surface and a uniform wall thickness and excellent watertightness. It is intended to provide a method for manufacturing a synthetic resin corrugated tube which can be continuously and efficiently molded in the vicinity of the.

[Means for solving problems]

The present invention has been invented in view of the above, at least two sheets of thermoplastic resin strip sheet pre-molded to form the inner and outer surface layers of the tubular body, and the intermediate layer of the tubular body by layering a plurality of layers. A multi-layered thermoplastic resin strip tape preformed to be formed is heated to a temperature not lower than the softening point and not higher than the melting point through a heating zone, and then a stratification layer is formed between the strip-shaped sheets forming the inner and outer surface layers. The strip-shaped tape is interleaved so that both sides of the strip-shaped tape are not laterally aligned with each other, and the strip-shaped tape and the strip-shaped tape forming the outer surface layer of the tubular body are flexible. While being wound spirally on a virtual cylindrical rotary shaft while interposing a core material consisting of a small-diameter tubular body having, a strip-shaped tape wound at least first and a strip-shaped tape wound later on hitting this winding. Is heavy Without rolling, form a tubular body by winding them in parallel with each other, and press-contact them with a pressing roll that is in contact with the virtual cylindrical rotary shaft body at a stage where the tubular body is still at a temperature between the softening point and the melting point. The problem was solved by fusing and cooling and hardening.

The features of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a partially cutaway perspective view illustrating a manufacturing process of the present invention, and FIG. 2 is a tubular body formed by the manufacturing process. Partial sectional view of the wall portion, FIG. 3 is a partial sectional view of the pipe wall portion of another embodiment of the same as above, FIG. 4 is a partially cutaway sectional view showing the manufacturing process of the same as above, and FIG. In the partially cutaway plan view shown in the figure, A is a virtual cylindrical rotary shaft body, B is a thermoplastic resin strip sheet forming the inner and outer surface layers of the tubular body a, and has a predetermined thickness and width in advance. A strip-shaped sheet formed into a long shape is wound into a roll, and C
Is a multi-leaf thermoplastic resin band tape for forming the intermediate layer of the tubular body a, which is formed into a long shape with a predetermined thickness and width in advance as in the case of the band sheet B, and is wound into rolls. D is a core material interposed between the strip-shaped sheet B forming the outer surface layer of the tubular body a and the strip-shaped tape C located on the outer surface layer side, and having a small diameter. It is composed of a flexible small-diameter tube body such as a corrugated tube. The strip-shaped sheet B and the strip-shaped tape C are heated to a temperature not lower than the softening point and not higher than the melting point through a heating zone E using a hot air, an infrared lamp or the like as a heat source, and then a stratified film is formed between the strip-shaped sheets B forming inner and outer surface layers. Between the strip-shaped tape B and the strip-shaped tape C forming the outer surface layer B of the tubular body a while interposing the strip-shaped tape C with laterally staggered positions so that both sides thereof are not aligned with each other. While the core material D is interposed between the virtual cylindrical rotary shaft body A and the peripheral surface of one end portion of the virtual cylindrical rotary shaft body A at the same time, the spiral material is supplied at the same time to be spirally wound and at the same time, the spirally wound belt shape is wound at least first. Tape C and band tape C wound afterwards
And are wound side by side so as to be juxtaposed to each other without being polymerized to form a tubular body a, and the tubular body a is placed at a temperature not lower than the softening point and not higher than the melting point to the virtual cylindrical rotating shaft A. The tubular body a is formed by pressure-bonding and fusion with a pressing roll F that is in contact with the pressure roll F, and cooling and curing while transferring to the other end side.

The virtual cylindrical rotating shaft A shown here is composed of a set of a plurality of rolls 1a, 1b, ...
1a, 1b, ... 1i are arranged side by side along a virtual circumference so as to maintain a constant space between adjacent rolls, and the front and rear ends thereof rotate on the base plate 2 and the bearing plate 3, respectively. The rollers 1a, 1b, ... 1i are arranged to support the bearing plate 3 to the base plate 2 by freely supporting them and substantially combining them to form one virtual cylindrical rotary shaft body. By rotating the rolls 1a, 1b, ... 1i supported by the base plate 2 in one direction, the bearing plate 3 is supported by one end of each of the rolls 1a, 1b, ... …
The band-shaped sheet B and the band-shaped tape C are spirally wound by twisting and tilting 1i around the axis of the virtual cylindrical rotary shaft A.

In addition, each of the rolls 1a, 1b, ... 1i is provided with a sprocket 4 on the shaft end on the front end side, and a chain 5 running on the rolls 1a, 1b, ... 1i rotates the rolls 1a, 1b ,. I am doing it.

Further, the strip-shaped sheet B used in the present invention is spirally wound around the virtual cylindrical rotary shaft A in order to further improve the water-tightness. It can be wound so that the belt-shaped sheet B and the belt-shaped sheet B are superposed on each other at the side portion, and can be formed to be thinner and wider than the belt-shaped tape C so that the step difference of the overlapped portion after the winding is extremely small. The strip-shaped sheet B, which is preferably used as the upper surface layer, may be bi-leaf layered as shown in FIG. On the other hand, strip tape C
Since a relatively thick wall within the allowable molding range is used as the composite tape, a composite tape in which a thermoplastic resin having a relatively low softening point such as low density polyethylene is layered on the fusion surface as shown in FIG. Is preferably used.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. A low-density polyethylene sheet having a thickness of 0.5 mm, which is preformed to form the inner and outer surface layers of the tubular body a and is wound into a roll. A two-leaf strip sheet B consisting of and a thickness of 1 m that has been preformed to form an intermediate layer and wound into a roll.
A strip-shaped sheet B whose width is m and forms the inner surface layer of the tubular body a.
Of a four-leaf strip tape C composed of a laminated sheet of a high-density polyethylene sheet and a low-density polyethylene sheet having a density of approximately ½ or less of When heated, the two-sided strip tapes C are laterally displaced so that the two side portions of the strip-shaped tapes C are not positioned on the same line, and the strip-shaped tapes C of the two-leaf strips that are arranged in parallel are positioned in upper and lower two stages. On the virtual cylindrical rotating shaft A, a core material D made of a corrugated pipe having a small diameter is interposed between a strip-shaped sheet B and a strip-shaped tape C which are interposed between the sheets B and form the outer surface layer of the tubular body. The strip-shaped tape C is wound into a spiral shape and wound so that at least the first strip-shaped tape C and the later-striped strip-shaped tape C that come into contact with this winding are juxtaposed to each other without being polymerized to form the tubular body a. And, tube body a is still virtual cylindrical rotating shaft body A at some stage to a temperature below the softening point or higher melting point
By pressing and fusing with a pressing roll F which is in contact with the surface of the belt, the inner surface is made substantially smooth as shown in FIG. A tubular body a having

〔The invention's effect〕

As is clear from the above, the present invention provides a preformed at least two-leaf thermoplastic resin strip sheet, a multi-leaf thermoplastic resin strip tape, and a core material made of a flexible small-diameter tubular body through a heating region. It is formed by spirally winding it on a virtual cylindrical rotary shaft, and since it conveys the equipment near the construction site according to demand and continuously forms it, the transportation cost is significantly reduced. When the strip tape is wound on the cylindrical rotary shaft, at least the first strip tape and the later strip tape are wound side by side without being polymerized to form a tubular body. Since it is formed, there is no level difference due to polymerization that has been seen in the past, and the initial purpose is to form a tubular body with a substantially smooth inner surface, which allows better running water, and also a surface layer and multiple intermediate layers. layer Features that the moldability is greatly improved because it is wound at the same time, and the watertightness is further improved because the layered band-shaped sheet and band-shaped tape are wound so that their positions are different from each other. It has one.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view illustrating a manufacturing process of the present invention,
2 is a partial sectional view of a tubular wall portion formed by the same manufacturing process as above, and FIG. 3 is a sectional view of a tubular wall portion of another embodiment of the same as above.
FIG. 4 is a partially cutaway sectional view showing the manufacturing process of the same as above, FIG. 5 is a partially cutaway plan view showing the manufacturing process of the same as above, and FIG. 6 is an example of the thermoplastic resin strip tape used in the present invention. It is a partially expanded sectional view shown. A: virtual cylindrical rotary shaft B: strip sheet C: strip tape D: core material E: heating area F: pressing roll a: tubular body

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Claims (4)

(57) [Claims] 1. A thermoplastic resin strip sheet of at least two leaves preformed to form inner and outer surface layers of a tubular body, and a plurality of leaves preformed to form an intermediate layer of the tubular body by laminating a plurality of layers. After heating the thermoplastic resin strip tape of (1) through a heating zone to a temperature of not less than the softening point and not more than the melting point, the strip tape to be a stratification tape is formed between the strip sheets forming the inner and outer surface layers on both sides of the strip tape. Cores made of a small-diameter tubular body having a flexibility between the strip-shaped sheet and the strip-shaped tape that are laterally displaced so that they are not on the same line as each other, and that form the outer surface layer of the tubular body. While the material is interposed, it is spirally wound on the virtual cylindrical rotary shaft body, and at least the previously wound band-shaped tape and the subsequently wound band-shaped tape are juxtaposed to each other without overlapping during the winding. Like And wound to form a tubular body, and at the stage where the tubular body is still at a temperature not lower than the softening point and not higher than the melting point, it is pressure-bonded by a pressing roll that is in contact with the virtual cylindrical rotary shaft body to be cooled and cured, 1. A method for producing a synthetic resin corrugated tube, which comprises continuously producing a tubular body having an inner surface which is substantially smooth and an outer surface having a spiral ridge formed by swelling of a belt-like sheet by encapsulating a core material. 2. When the strip-shaped sheet is spirally wound on the virtual cylindrical rotary shaft, the strip-shaped sheet previously wound and the strip-shaped sheet wound later can be wound so as to be superposed at the side portions. A method of manufacturing a synthetic resin corrugated tube according to claim 1. 3. The method for producing a synthetic resin corrugated tube according to claim 1, wherein a thin sheet having a wider width than that of the strip tape is used as the strip sheet. 4. A composite tape comprising a layered body of a high-density polyethylene tape and a low-density polyethylene tape used as a strip tape.
A method for producing a synthetic resin corrugated tube according to the item.