JP2020131481A - Method for manufacturing reinforced band material of spiral tube band member - Google Patents

Abstract

To ensure a required thickness of a resin layer on a surface side of a bent part which is convex when a reinforced band material of a spiral tube band member is bent and formed.SOLUTION: In a coating step, a resin layer 30 is coated on a surface of a metal band plate 29X that serves as a reinforced band material 20 in a band member 3. By bending planned bending parts 25x, 26x, 27x of the coated band plate 29X, the reinforced band material 20 is formed into a predetermined sectional shape. In the coating step, thickness of resin layers 35a, 36b, 37b in convex surface parts 25xa, 26xb, 27xb of the planned bending parts 25x, 26x, 27x is formed to be thicker than thickness of resin layers 38a, 38b on flatly retained surface parts 28xa, 28xb on a same surface side as the convex surface parts of the band plate 29X.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method for manufacturing a reinforcing band material in a band-shaped member to be a spiral pipe, and particularly to manufacture a reinforcing band material in a band-shaped member for a spiral pipe to be a rehabilitated pipe lined on the inner circumference of an existing aging buried pipe. Regarding the method.

A method of spirally lining a band-shaped member on the inner peripheral surface of an existing buried pipe such as an aged sewer pipe to rehabilitate it is known (see Patent Document 1 and the like). For example, the strip-shaped member described in Patent Document 1 is attached to a main strip made of synthetic resin such as polyvinyl chloride (PVC) and a back side portion thereof (a side portion facing the outer peripheral side when molded into a spiral tubular shape). It is equipped with a reinforcing band material. The main material of the reinforcing strip is a steel strip, and the entire surface thereof is covered with a resin layer for high durability. The reinforcing strip is formed into, for example, a substantially W-shaped predetermined cross-sectional shape.

Japanese Unexamined Patent Publication No. 2009-23296

As a method for manufacturing the reinforcing strip, for example, the entire surface (both sides and both ends) of the main steel strip is covered with resin by co-extrusion, and then a predetermined cross-sectional shape is given by bending molding such as roll forming. To do. During the bending molding, the resin layer on the convex surface side of the bent portion is stretched to become thin. Therefore, it is conceivable that the required resin thickness cannot be secured. As a countermeasure, if the thickness of the resin layer on the entire surface of the reinforcing strip is increased, the material cost of the resin layer will increase and the thickness of the reinforcing strip will increase as a whole, resulting in bending formability by roll forming. It may get worse. Further, it is conceivable that the workability when manufacturing a spiral pipe is deteriorated.
In view of such circumstances, the present invention determines the required thickness of the resin layer on the convex surface side of the bent portion when the reinforcing strip member of the spiral pipe strip-shaped member is bent-molded, which increases the resin material cost and deteriorates the bend-formability. The purpose is to ensure that the pipe-making workability is not deteriorated.

In order to solve the above problems, the present invention is a method for manufacturing a reinforcing strip having a predetermined cross-sectional shape to be attached to a main strip made of synthetic resin in a strip member to be a spiral tube.
A coating process that coats the surface of a metal strip with a resin layer,
Including a bending forming step of forming the reinforcing strip material by bending a bending portion of the strip after coating.
In the coating step, the thickness of the resin layer on the convex surface portion of the planned bending portion is held flat on the same surface side as the convex surface portion of the strip. It is characterized by making it larger than the thickness of.
By the bending molding step, the resin layer on the convex surface portion is stretched in the width direction and the thickness is reduced. Since the resin layer on the convex surface portion is formed thick in the coating step, the required thickness is secured even if the thickness is reduced by bending molding. By thinning the resin layer in the portion other than the convex surface portion, an increase in resin material cost and the like can be suppressed.
The thickness of the resin layer in the convex surface portion is preferably 1.1 to 2 times the thickness of the resin layer in the surface portion held flat.

According to the present invention, it is possible to secure the required thickness of the resin layer on the surface side where the bent portion becomes convex when the reinforcing strip material of the spiral pipe strip-shaped member is bent and molded. Moreover, it is possible to avoid an increase in resin material cost, deterioration in bending moldability, deterioration in pipe making workability, and the like.

FIG. 1 is a cross-sectional view of a strip-shaped member according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a part of a rehabilitation pipe (spiral pipe) made from the strip-shaped member and lined on the inner circumference of the existing pipe. FIG. 3 is a perspective view showing a schematic configuration of an apparatus for manufacturing a reinforcing strip material in the strip-shaped member. FIG. 4 is a cross-sectional view showing an extrusion mold in the manufacturing apparatus along the line IV-IV of FIG. FIG. 5A is a cross-sectional view showing a strip of the reinforcing strip along the Va-Va line of FIG. FIG. 5B is a cross-sectional view showing a strip after resin coating and before bending and forming along the Vb-Vb line of FIG. FIG. 6 is a cross-sectional view of the reinforcing strip along the VI-VI line of FIG. FIG. 7 is a cross-sectional view showing each of the three bent portions on the left side of the paper surface of FIG. 6 enlarged from the central portion in the width direction of the reinforcing strip. FIG. 8 is a cross-sectional view of the reinforcing strip according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a strip-shaped member 3 according to the present embodiment. The strip-shaped member 3 has a constant cross-sectional shape and extends in a long shape in a direction orthogonal to the paper surface of FIG.
As shown in FIG. 2, the strip-shaped member 3 is used for rehabilitation of an aging existing buried pipe 1. The buried pipe 1 to be rehabilitated is, for example, a sewer pipe. The buried pipe 1 is not limited to a sewer pipe, and may be a water pipe, an agricultural water pipe, a hydroelectric power guiding pipe, a gas pipe, or the like. The strip-shaped member 3 is spirally lined along the inner circumference of the buried pipe 1 to form a rehabilitation pipe 2 (spiral pipe).

As shown in FIG. 1, the band-shaped member 3 includes a main band member 10 and a reinforcing band member 20. The material of the main band material 10 is a synthetic resin such as polyvinyl chloride. The main strip 10 is formed into a constant cross section by extrusion molding of the synthetic resin.
As shown in FIG. 2, in the spiral tubular rehabilitation tube 2 made of the strip-shaped member 3, the fitting portions 13 and 14 adjacent to each other on both side edges of the spirally wound main strip 10 are uneven. It is fitted.

As shown in FIG. 1, a reinforcing strip 20 is attached to the back side portion of the main strip 10 (the side facing the outer peripheral side (upper side in FIG. 2) when the spiral pipe 2 is manufactured). The reinforcing strip 20 is formed in a predetermined cross-sectional shape and extends parallel to the main strip 10 in the direction orthogonal to the paper surface of FIG.

As shown in FIG. 6, for example, the reinforcing strip 20 has a top plate portion 21, a pair of side plate portions 22, a pair of bottom plate portions 23, and a pair of swash plate portions 24. A pair of bottom plate portions 23 are addressed to the back side surfaces of the main strip member 10, respectively. The swash plate portions 24 project diagonally outward from the ends of the bottom plate portions 23 facing opposite sides. The ends of the swash plate portions 24 are locked to the locking portions 15 and 16 of the main band member 10. Side plate portions 22 stand up from the end portions of the pair of bottom plate portions 23 facing each other to the back side. The top plate portion 21 is bridged between the protruding ends of the pair of side plate portions 22 toward the back side.

Between the top plate portion 21 and each side plate portion 22, a mountain fold portion 25 bent by approximately 90 ° in a mountain fold when viewed from the back side (upper in FIG. 6) is formed.
Between the side plate portion 22 and the bottom plate portion 23, a valley fold portion 26 bent by approximately 90 ° in a valley fold when viewed from the back side is formed.
Between the bottom plate portion 23 and the swash plate portion 24, a valley fold portion 27 that is bent at an angle smaller than 90 ° is formed in a valley fold when viewed from the back side.
The portion of the reinforcing strip 20 excluding the bent portions 25, 26, and 27 is a flat portion 28.

As shown in FIG. 6, the reinforcing strip 20 includes a strip 29 as a main material and a resin layer 30. The strip 29 is made of steel (metal). The thickness of the strip 29 is preferably about 0.5 mm to 2 mm, more preferably about 0.8 mm to 1.6 mm. As shown in FIG. 7, the radii of curvature R ₂₅ , R ₂₆ , and R ₂₇ of the thickness center of the strip 29 (the alternate long and short dash line in FIG. 7) at each of the bent portions ₂₅ , ₂₆ , and ₂₇ are preferably at least about 1 mm, respectively. ..

As shown in FIG. 6, the entire surface of the strip 29 (both side surfaces 29a, 29b and both end surfaces 29e) is covered with the resin layer 30. The resin layer 30 is made of a resin having an elongation rate of 20% or more. Examples of such a resin include linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and polypropylene (PP). In particular, it is preferable that an olefin-based thermoplastic elastomer is added to the resin layer 30 made of PP. Thereby, the growth rate can be changed.
The resin layer 30 may contain an adhesive modified polyolefin such as modified polyethylene or modified polypropylene. Examples of the modified polyolefin include Admer (registered trademark) manufactured by Mitsui Chemicals, Inc.

As shown in FIG. 6, the resin layer 30 includes an outer layer portion 31 and an inner layer portion 32. The outer layer portion 31 covers the outer surface 29a of the strip 29 facing the back side. The inner layer portion 32 covers the inner side surface 29b of the strip 29 facing the main strip 10 side.
Specifically, as shown in FIG. 7, the outer layer portion 31 includes an outer flat layer portion 38a that covers the outer surface 29a of the flat portion 28, and a mountain fold convex layer portion 35a that covers the convex portion 25a of the mountain fold portion 25. Includes valley-folded concave layer portions 36a, 37a that cover the concave-faced portions 26a, 27a of the valley-folded portions 26, 27, respectively.

The inner layer portion 32 includes an inner flat layer portion 38b that covers the inner side surface 29b of the flat portion 28, a mountain fold concave layer portion 35b that covers the concave portion 25b of the mountain fold portion 25, and a convex portion 26b of the valley fold portions 26 and 27. , 27b include valley fold convex layer portions 36b and 37b, respectively.

The thickness of the outer layer portion 31 is larger than the thickness of the inner layer portion 32. Preferably, the required thickness of the outer layer portion 31 is about 1.0 mm to 1.5 mm in order to secure a scratch margin and prevent corrosion. The required thickness is satisfied not only in the flat layer portion 38a and the concave layer portions 36a and 37a in the outer layer portion 31 but also in the convex layer portion 35a.
The required thickness of the inner layer portion 32 is preferably about 0.5 mm or more and less than or equal to the thickness of the outer layer portion 31 in consideration of the corrosion prevention function. The required thickness is satisfied not only in the flat layer portion 38b and the concave layer portion 35b in the inner layer portion 32 but also in the convex layer portions 36b and 37b.

The reinforcing strip 20 is produced as follows.
<Steel strip 29X>
As shown in FIG. 3, the steel strip 29X (blank) to be the strip 29 is fed out from the roll-shaped strip winding body 41. As shown in FIG. 5A, the cross section of the strip 29X at this stage is flat. The strip 29X is set with a mountain bending portion 25x that should be a mountain bending portion 25 and a valley bending planned portion 26x, 27x that should be a valley bending portion 25, 26, 27. The portion of the strip 29X excluding the planned bending portions 25x, 26x, and 27x is the non-scheduled bending portion 28x that should be the flat portion 28. The non-bending plan portion 28x includes an outer flat surface portion 28xa and an inner flat surface portion 28xb held on the flat surface.

<Coating process>
As shown in FIG. 3, the strip 29X is introduced into a coating treatment section 42 made of a coextruder of the reinforcing strip manufacturing apparatus 40. The raw material resin 30x of the resin layer 30 is supplied to the coating treatment section 42, and the resin layer 30 is coated on the entire surfaces 29b, 29a, 29e of the strip 29X by coextrusion molding (FIG. 5B).
The outer layer portion 31 is coated on the outer surface 29a of the strip 29X. The inner side surface 29b is covered with the inner layer portion 32.

As shown in FIG. 4, a recess 45 is formed in a portion corresponding to the mountain fold convex layer portion 35a on the mold surface 43a for the outer layer portion 31 of the extrusion molding die 43 of the coating treatment portion 42. The mold surface 43b for the inner layer portion 32 of the extrusion mold 43 is formed with recesses 46 and 47 at locations corresponding to the valley fold convex surface layer portions 36b and 37b, respectively.

As a result, as shown in FIG. 5B, the thickness of the resin layer 30 of the convex surface portions 25xa, 26xb, 27xb at the planned bending portions 25x, 26x, 27x of the stripped plate 29X becomes convex. It is larger than the thickness of the resin layer 30 in the surface portions 28xa and 28xb held flat on the same surfaces 29a and 29b as the surface portions 25xa, 26xb and 27xb. That is, the thickness of the convex layer portion 35a in the mountain bending planned portion 25x is larger than the thickness of the flat layer portion 38a in the outer flat surface portion 28x, and by extension, the thickness of the outer layer portion 31 is larger than the required thickness. The thickness of the convex layer portions 36b and 37b at the planned valley bending portions 26x and 27x is larger than the thickness of the flat layer portion 38b at the inner flat surface portion 28xb, and thus is larger than the required thickness of the inner layer portion 32.
It is possible to suppress an increase in the resin material cost of the resin layer 30 by partially thickening only the convex layer portions 35a, 36b, 37b which are thinned by bending molding, instead of thickening the entire resin layer 30. ..
The thickness of the convex layer portions 35a, 36b, 37b during the coating step is preferably about 1.1 to 2 times, more preferably about 1.5 times, the thickness of the flat layer portions 38a, 38b on the same surface side. .. For example, when the thickness of the flat layer portion 38b is 0.5 mm, the thickness of the convex layer portions 36b and 37b at the time of the coating step is preferably about 0.75 mm.

Further, the widths of the recesses 45, 46, 47 in the extrusion mold 43 are set to be substantially the same as the peripheral lengths of the corresponding convex portions 25a, 26b, 27b. As a result, the width of the convex layer portions 35a, 36b, 37b becomes about the same as the peripheral length of the corresponding convex surface portions 25a, 26b, 27b. For example, when the set radius of curvature of the convex surface portion 26b is 3.7 mm, the convex surface layer portion 36b having a width of 3.7 × 2π × (1/4) = about 5.8 mm is formed.

<Bending molding process>
As shown in FIG. 3, subsequently, in the bending forming portion 44, the strip plate 29X is bent to form the reinforcing strip 20 (FIG. 6) having a predetermined shape. Preferably, the bending forming section 44 is configured by a roll forming machine including a multi-stage (plural) forming roll. The planned bending portions 25x, 26x, 27x of the strip 29X are gradually bent by the forming roll of each stage, and the predetermined shape is given. Buckling can be prevented by gradually deforming by multi-stage roll forming.
Since only the convex layer portions 35a, 36b and 37b are thickened and most of the resin layer 30 except for the convex layer portions 35a, 36b and 37b is not thickened, it is possible to prevent the bending formability from deteriorating. ..

Along with the bending molding, the convex layer portions 35a, 36b, 37b on the convex portions 25a, 26b, 27b are stretched in the width direction to reduce the thickness. On the other hand, since these convex layer portions 35a, 36b, 37b are formed to be thick in the coating step, the required thickness can be secured even if the thickness is reduced by bending molding. Preferably, depending on the thickness setting during the coating process, the mountain fold convex layer portion 35a finally has the same thickness as the outer flat layer portion 38a, and the valley fold convex layer portions 36b and 37b finally become inner. The thickness is equivalent to that of the flat layer portion 38b.
For example, when the thickness of the flat layer portion 38b at the time of the coating step is 0.5 mm and the thickness of the convex layer portions 36b and 37b is 0.75 mm, the thickness of the flat layer portion 38b becomes 0. While the thickness of the convex layer portions 36b and 37b is maintained at 5 mm, the thickness of the convex layer portions 36b and 37b is reduced from 0.75 mm to about 0.5 mm.
As a result, the overall thickness of the resin layer 30 can be made the minimum necessary size.

In this way, the reinforcing strip 20 is created. According to the reinforcing strip 20, the resin layer 30 can protect the steel strip 19, and prevent corrosion and damage of the strip 29. In particular, by ensuring the minimum necessary thickness of the convex layer portions 35a, 36b, 37b that are thinned by bending molding, corrosion and damage of the convex surface portions 25a, 26b, 27b can be reliably prevented.
The strip-shaped member 3 is formed by fitting the reinforcing strip 20 to the resin main strip 10. The strength of the strip-shaped member 3 can be increased by the reinforcing strip 20.
The strip-shaped member 3 is lined on the inner circumference of the existing pipe 1 to form the rehabilitation pipe 2. Since the thickness of the resin layer 30 is suppressed to the minimum necessary size as a whole, for example, the width of the drive roller of the pipe making machine is not limited, and the weight of the strip-shaped member 3 does not increase. , Pipe making workability can be improved.
Since the corrosion resistance of the reinforcing strip 20 is enhanced by the resin layer 30, the durability of the rehabilitation pipe 2 can be improved. By imparting independence to the rehabilitation pipe 2 by the reinforcing strip material 20, it is not necessary to inject a backfill material between the existing pipe 1 and the rehabilitation pipe 2.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the thickness of the convex layer portions 35a, 36b, 37b may be adjusted according to the curvature of the corresponding bending portions 25, 26, 27. That is, the larger the curvature, the larger the thickness may be.
Regarding the concave layer portions 35b, 36a, 37a, the concave layer portion 35b may be thinner than the flat layer portion 38b during the coating process in consideration of the thickening due to compression in the width direction during bending molding, and the concave layer portion 36a , 37a may be thinner than the flat layer portion 38a. The thickness of the concave layer portions 35b, 36a, 37a may be reduced as the curvature of the corresponding bent portions 25, 26, 27 increases.
The resin layer 30 may have a multi-layer structure in which a plurality of resin films are laminated. Adhesiveness may be imparted to the resin film in contact with the strip 29.
The cross-sectional shapes of the main band member 10 and the reinforcing band member 20 are not limited to those of the embodiment, and various cross-sectional shapes can be applied. For example, as shown in FIG. 8, the reinforcing strip 20B may have a W-shaped cross section. Also in the reinforcing strip 20B, the thickness of the resin layer (flat layer portion 39b) in the surface portion where the thickness of the resin layer (convex layer portion 39a) in the convex surface portion of the planned bending portion in the coating process is kept flat. By making it larger than that, the required thickness of the resin layer (convex layer portion 39a) in the convex portion of the bent portion 20b after bending and molding can be secured.

The present invention can be applied to rehabilitation of buried pipes such as sewer pipes.

1 Existing buried pipe 2 Rehabilitation pipe (spiral pipe)
3 Band-shaped member 10 Main band 20 Reinforcing band 20B Reinforcing band 25 Mountain bending part (bending part)
25x mountain bending planned part (bending planned part)
25xa Convex surface part 26 Valley bending part (bending part)
26x Valley Bending Scheduled Part (Bending Scheduled Part)
26xb Convex surface portion 27 Valley bending part (bending part)
27x Valley Bending Scheduled Part (Bending Scheduled Part)
27xb Convex surface portion 28 Flat portion 28x Non-bending planned portion 28xa, 28xb Flat surface portion (surface portion held flat)
29X Strip plate before bending 30 Resin layer 35a Mountain fold convex layer portion (resin layer in the convex surface portion)
36b, 37b Valley fold convex surface layer portion (resin layer in the convex surface portion)
38a, 38b Flat layer portion (resin layer in the surface portion held flat)

Claims (2)

It is a method of manufacturing a reinforcing band material having a predetermined cross-sectional shape attached to a main band material made of synthetic resin in a band-shaped member to be a spiral tube.
A coating process that coats the surface of a metal strip with a resin layer,
Including a bending forming step of forming the reinforcing strip material by bending a bending portion of the strip after coating.
In the coating step, the thickness of the resin layer on the convex surface portion of the planned bending portion is held flat on the same surface side as the convex surface portion of the strip. A method for manufacturing a reinforcing strip material for a strip-shaped member, which is characterized in that the thickness is larger than the thickness of. The first aspect of the present invention, wherein the thickness of the resin layer on the convex surface portion is 1.1 to 2 times the thickness of the resin layer on the surface portion held flat. Reinforcing strip manufacturing method.

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