JP2002257269A - Corrugated pipe made of synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synthetic resin, made duplex pipe that can prevent the occurrence of wrinkles inside an inner pipe, and has high durability and molding property. SOLUTION: This synthetic resin made double pipe H comprises an outer pipe 1 axially and alternately having spiral crest parts 1a and troughs 2a on its outer surface and the cylindrical inner pipe 2, integrally jointed to the inner surface of respective troughs 2a of the outer pipe. The outer pipe 1 is made of rigid thermoplastic resin, and the inner pipe 2 is made of a polyolefin-based thermoplastic elastomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrugated pipe made of synthetic resin, and more particularly to a corrugated pipe installed in a building, particularly in a detached house, outdoors, underground, or the like, and is used for fluids, gases, resin pellets and dust. The present invention relates to a synthetic resin corrugated pipe suitable for use as a pipeline for transporting solid matter such as dust.

[0002]

2. Description of the Related Art Conventionally, as a conduit for transporting this kind of fluid, a corrugated tube having a tube outer wall having an irregular shape in the axial direction, specifically, a helical or annular tube is provided outside a cylindrical tube main body. A synthetic resin double pipe consisting of an outer pipe in which ridges and valleys are provided alternately in the axial direction, and a tubular inner pipe integrally joined at the inner surface of the valley of the outer pipe, and a pipe outer wall Synthetic resin straight pipes whose shape is linear in the axial direction are well known, and are already widely used as feed / drain pipes or transport pipes for various substances.

[0003]

However, in the case where the inner surface of the inner tube is made smooth for the purpose of enhancing the transport performance and the like of these conventional synthetic resin double tubes, the flexibility is reduced, so There is a problem that the pipe is crushed or wrinkles protrude on the inner surface to reduce the transport capacity.

Further, for the purpose of solving this problem, as disclosed in Japanese Utility Model Laid-Open Publication No. 62-66084 and Japanese Patent Laid-Open Publication No. Hei 10-122448, a rubber soft band having a hard reinforcing wire is spirally wound. wrapped around the, by a tubular body constituted by a rubber soft strip at least the inner surface, but prevents protrusion of wrinkles to the inner surface of the tubular body is that increased flexibility, rubber soft strip is There is a problem that the durability is poor because the inner surface is exposed, and the rubber raw material requires a vulcanization step to develop the properties of rubber after extrusion, so the molding processability is not good, and the molecular chains are crosslinked. There was a problem that recycling was difficult.

[0005]

According to the present invention, there is provided a tube main body, and a reinforcing member provided spirally or annularly in the axial direction outside the tube main body, and the reinforcing member is made of a hard synthetic resin. And a synthetic resin corrugated pipe whose entire or inner surface is formed of a thermoplastic elastomer or an ethylene-based copolymer that is smooth and does not generate wrinkles when bent.

That is, according to the present invention, when the inner surface of the tube main body is formed of a thermoplastic elastomer or an ethylene-based copolymer, the inner surface of the tube main body is bent, for example, when the inner surface of the tube main body is formed of a thermoplastic elastomer. When the wrinkle does not occur at the time of bending, the inner diameter of the pipe body is 25 to 600
When the bending radius R with respect to mmD is R / D> 1 or more, and when the entire tube body is formed of a thermoplastic elastomer, the bending that does not generate wrinkles at bending is the inner diameter of the tube body: 2
The bending radius R is R / D> 0.5 for 5 to 600 mmD.
In addition to preventing the occurrence of wrinkles on the inner surface, the durability and molding processability are improved, and the recyclability is also improved. In short, the synthetic resin corrugated pipe of the present invention, by using a specific elastic material or a soft resin material for the inner surface of the pipe body, enables the prevention of wrinkles and the good durability and moldability together,
In addition, recyclability can be further improved.

Here, the pipe body of the synthetic resin corrugated pipe of the present invention means a cylindrical body having a circular cross section at least on the inner surface of the through-hole, and usually the inner and outer cross sections of the tubular body are both A circular cylindrical body is employed. Examples of the thermoplastic elastomer used as a material of the pipe main body include polystyrene-based, polydiolefin-based, vinyl chloride-based, polyolefin-based, chlorinated polyethylene-based, polyurethane-based, polyester-based, fluorine-based, and silicone-based elastomers. In particular, when the outer tube is made of a polyolefin-based resin, an olefin-based thermoplastic elastomer is more preferable because it has the highest weldability. Further, as the thermoplastic elastomer, a dynamically crosslinked thermoplastic elastomer in which a rubber component highly crosslinked by sulfur or peroxide is finely dispersed therein can be used. Still dynamic thermoplastic elastomer in particular, can be mentioned Santoprene [er Iesu Japan Ltd.]. Examples of the ethylene-based copolymer used as the material of the tube body include an ethylene-vinyl acetate copolymer, an ethylene / methyl methacrylate copolymer or an ethylene-ethyl acrylate copolymer. In the case of a resin, an ethylene-vinyl acetate copolymer is more preferable because of high welding property.

On the other hand, as the rigid thermoplastic resin used as the material of the reinforcing member, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, include polystyrene, polyvinyl chloride, ABS resin And a polyethylene resin is more preferred. Note that the synthetic resin corrugated pipe according to the present invention means a variety of synthetic resin pipe for feeding the material discharge, in particular can prevent the occurrence of inner surface wrinkles, and their good durability,
Because of its flexibility, buckling strength, etc., it can be suitably used for pipes for transporting various substances used in the ground or inside buildings.

[0009] synthetic resin corrugated pipe according to the present invention is preferably a synthetic resin double tube monolithic. That is, the reinforcing member is formed into an outer tube (or outer tube) having ridges and valleys alternately arranged in a spiral or annular shape in the axial direction, and the tube body is integrally joined to the inner surface of the outer tube. Tube (or inner tube). Here, it is preferable that the outer tube is formed of a high-density polyethylene, a medium-density polyethylene, or a low-density polyethylene resin, and the inner tube is formed of a polyolefin-based thermoplastic elastomer. Furthermore, the inner tubular part,
By weight, 100% to 30% thermoplastic elastomer,
It may be formed of a mixture with 0% to 70% of a hard synthetic resin. Also the inner tubular part, by weight, ethylene copolymer 0%
To 50% and 100% to 50% of a hard synthetic resin.

Next, an example of a method for manufacturing the synthetic resin double pipe will be briefly described, but the present invention is not limited to this. First, on the peripheral surface of the cylindrical rotating mandrel, spirally winding the melted band of the thermoplastic elastomer from the extruder so as to partially overlap, forming the inner tube part,
Further, on the peripheral surface of the inner tube portion, a molten band-shaped body of a synthetic resin (high-density polyethylene resin or medium-density polyethylene resin) is supplied separately so that the cross section is bent and a part of the band is overlapped. By forming the outer surface, the inner surface has a substantially circular cross section, and the outer surface has spiral ridges and valleys alternately arranged in the axial direction on the outer surface, and the inner surface of each valley of the outer tube is integrally formed. A synthetic resin corrugated pipe (double pipe) composed of the joined cylindrical inner pipe portion can be obtained (for details, see Japanese Patent Publication No. 5-72852).

Further, the molten resin is poured into a mold having an outer tube forming surface having alternating annular concave and convex portions and an inner tube forming surface having the same diameter as the concave portion of the outer tube forming surface. extruding molten resin to the outer pipe section molding surface (high density, medium density or low density polyethylene resin) while forming an outer tube portion of,
The outside pipe section from the inner tube portion forming surface extruding molten resin (thermoplastic elastomer) into a tubular shape, and produce a differential pressure between the inside and outside, the molten resin is adhered to the valleys inner surface of the outer tube portion By heat-sealing, by forming a cylindrical molten resin inner tube part, instead of a spiral shape on the outer surface of the outer tube part,
An annular ridge and a valley are alternately provided in the axial direction, and a corrugated pipe (double pipe) made of a synthetic resin having substantially the same configuration as that of the above-described example can be obtained.
No. 7). In addition, after extruding the inner tube portion into a tube shape, the reinforcing agent may be wound around to form a double tube.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. Note that the present invention is not limited by this. First, FIG. 1 is a partially cutaway front view showing one embodiment of a synthetic resin corrugated pipe according to the present invention, and FIG. 2 is an enlarged sectional view of a main part of FIG.

1 and 2, a double pipe H for transporting clean water is shown.
Is an outer tube 1 as a reinforcing member having a spiral ridge 1a and a valley 1b alternately and continuously provided in the axial direction on the outer surface, and a tube integrally joined at the inner surface of the valley 1b of the outer tube. The outer tube 1 is formed of a high-density or medium-density polyethylene resin, and the inner tube 2 is formed of a polyolefin-based thermoplastic elastomer.

Thus, even if the transport double pipe H is arranged in a bent state in the soil or in a joint box, the outer pipe 1 is made of a high-density or medium-density polyethylene resin, and the inner pipe 2 is made of a polyolefin-based thermoplastic elastomer. Since it is formed of wrinkles, the generation of wrinkles on the inner surface of the inner tube 2 can be suppressed, and the buckling strength, tear strength, durability and recyclability are good. Needless to say, the polyolefin-based thermoplastic elastomer as the material of the inner tube 2 does not require a vulcanizing step like a rubber material such as a styrene-butadiene copolymer or chloropyrene, and is easily processed. Furthermore,
Compared with rubber materials such as styrene / butadiene copolymer, isoprene rubber, and natural rubber, they have good water resistance, acid resistance, and alkali resistance, and also have good weather resistance.

Here, for reference, an example of material and dimensional specifications of the double pipe H for transportation is provided (however, the standard length dimension is 4000 m).
m). The inner tube (cylindrical tube) (which ethylene-propylene-diene copolymer particles in a matrix of polyolefin was finely dispersed, Shore hardness: 60A) inner diameter: 49 mm Outer diameter: 50mm outer pipe (high-density polyethylene resin) inside diameter (Valve outside diameter): 51 mm Outside diameter (peak outside diameter): 60 mm In the above-mentioned transport double pipe H, the outer pipe part is formed of a hard polyethylene resin, but mainly its peak / valley part. Radius of curvature of about 50m due to the structure having
At m, no wrinkles were formed on the inner surface of the inner tube portion.

[0016] Unlike the above embodiment, the outer tube, outside the inner tube, rather than helically, can be provided alternately peaks and valleys axially annular.

[0017]

According to the synthetic resin corrugated pipe of the present invention, the reinforcing member is made of a hard thermoplastic resin, and the inner surface of the pipe body is made of an elastic material made of a thermoplastic elastomer or an ethylene copolymer. In addition, when the corrugated pipe is bent, no wrinkles are generated on the inner surface of the pipe main body, so that a connecting device at a bent portion is not required, and the construction can be simplified, and the recyclability is improved.

[Brief description of the drawings]

FIG. 1 shows a synthetic resin corrugated pipe 1 according to the present invention.
It is a partially broken front view which shows one Embodiment.

Figure 2 is an enlarged sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer pipe 1a Mountain part 2 Inner pipe 2a Valley H Double pipe made of synthetic resin for transportation

Continued on front page F-term (reference) 3H111 AA02 BA15 BA34 CA12 CA43 CB02 CB03 CB29 CC13 CC19 DA26 DB05 DB13 EA04 4F100 AK01A AK01B AK03C AK04C AK05B AK06B DA AK10C AK12C AK15C AK17C AK28C BAK DE01C DH00B EJ05C JB16C JK04 JK12A JK12B

Claims (12)

[The claims] 1. A pipe main body, and a reinforcing member spirally or annularly provided along the axial direction outside the pipe main body, wherein the reinforcing member is formed of a hard synthetic resin. A synthetic resin corrugated pipe whose whole or inner surface is formed of a thermoplastic elastomer or an ethylene-based copolymer that is smooth and does not generate wrinkles when bent. 2. The synthetic resin corrugated pipe according to claim 1, wherein the pipe main body is formed of a hard synthetic resin except for an inner surface thereof. 3. The thermoplastic elastomer according to claim 1, wherein the thermoplastic elastomer is a polystyrene, polydiolefin, vinyl chloride, polyolefin, chlorinated polyethylene, polyurethane, polyester, fluorine or silicone elastomer. The synthetic resin corrugated pipe described in the above. 4. The synthetic resin corrugated pipe according to claim 3, wherein the thermoplastic elastomer is a polyolefin-based thermoplastic elastomer. 5. The synthetic resin according to claim 1, wherein the thermoplastic elastomer is a dynamically crosslinked thermoplastic elastomer in which a rubber component crosslinked by sulfur or peroxide is finely dispersed. Corrugated pipe. 6. The ethylene copolymer is, claim 1 ethylene vinyl acetate copolymer, ethylene / methyl methacrylate copolymer or an ethylene ethyl acrylate copolymer
Or synthetic resin corrugated pipe according to 2. 7. An inner tube in which a reinforcing member is an outer tube portion having a helical portion or an annular portion having ridges and valleys alternately arranged in an axial direction, wherein a tube main body is integrally joined to an inner surface of the outer tube portion. synthetic resin corrugated pipe as claimed in any one of claims 1 to 6 is a tubular part. 8. A bending, the inner diameter of the pipe main body D (mm), if the bend value was R (mm), the synthesis according to any one of claims 1 to 7, the R / D> 1 plastic corrugated pipe. 9. The whole pipe body is formed of a thermoplastic elastomer which is smooth and does not generate wrinkles when bent, and the bending is performed when the inner diameter of the pipe body is D (mm) and the bending value is R (mm). The synthetic resin corrugated pipe according to any one of claims 1 to 5, wherein R / D> 0.5. 10. The method according to claim 1, wherein the outer tube is formed of a high-density polyethylene or a medium-density polyethylene resin or a low-density polyethylene, and the inner tube is formed of a polyolefin-based thermoplastic elastomer. Or 1
Synthetic resin corrugated pipe according to One. 11. An inner tube portion comprising, by weight, 100% to 30% of a thermoplastic elastomer and 0% to 70% of a hard synthetic resin.
The synthetic resin corrugated pipe according to any one of claims 1 to 5, and 7 to 10, which is formed of a mixture of: 12. The inner tube part is formed by a mixture of 0% to 50% of an ethylene copolymer and 100% to 50% of a hard synthetic resin in a weight ratio. 8. The synthetic resin corrugated pipe according to any one of 8.