JP7381206B2 - resin tube - Google Patents

Description

The present invention relates to resin pipes.

BACKGROUND ART Conventionally, the use of resin pipes (pipe bodies) made of olefin resin such as polyethylene resin to transport fluids such as water has been considered (for example, see Patent Document 1). By forming the resin pipe with olefin resin, corrosion of the resin pipe can be suppressed.

In order to distinguish resin pipes from each other, resin pipes are colored light blue, black, etc. As the number of types of resin pipes increases, it will no longer be possible to distinguish them just by the color of the resin pipes. For this reason, the inventors are considering a resin tube that includes a tube body and a band-shaped portion formed on the outer circumferential surface of the tube body so as to extend over the entire length of the tube body. The band-shaped portion is formed in a part of the tube body in the circumferential direction. If the color of the tube body and the color of the strip are made different from each other, even if the number of types of resin tubes increases, the resin tubes can be distinguished from each other by the color of the tube body and the color of the strip.

JP2007-268628A

A stencil (indicator) is provided on the resin pipe to indicate the product name, model number, etc. of the resin pipe. The stencil is provided so as to extend over the entire length of the resin tube so that the stencil can be easily seen at any position in the axial direction of the resin tube.

However, if the stencil is provided across both the exposed surface of the outer circumferential surface of the tube body that is not covered by the strip and the outer surface of the strip, the stencil becomes difficult to see.

The present invention has been made in view of these problems, and an object of the present invention is to provide a resin tube with easy-to-see indicators.

In order to solve the above problems, the present invention proposes the following means.
The resin pipe of the present invention includes a pipe body for connecting to an electric fusion joint , and is formed integrally with the pipe body on the outer circumferential surface of the pipe body so as to extend over the entire length of the pipe body, and has a A band-shaped portion having a circumferential width of 4 mm or more and 50 mm or less, and a ratio of the width to the outer diameter of the tube body is 5% or more and 30% or less, and the outer circumferential surface of the tube body is covered with the band-shaped portion. an exposed surface that is not exposed, and an indicator provided on only one of the outer surfaces of the band-shaped part so as to extend over the entire length of the tube body, and the thickness of the band-shaped part is 0.02 mm or more and 2.0 mm. and is characterized by being thinner than the thickness of the tube body .

Moreover, in the resin pipe described above, the thickness of the band-shaped portion may be 0.1 mm or more and 0.5 mm or less.
Moreover, in the resin tube described above, the indicator may be provided on the exposed surface of the tube body and the outer surface of the band-shaped portion, whichever is longer in the circumferential direction of the tube body.
According to this invention, by providing the index on a surface having a long circumferential length, the index can be more easily seen on a wide surface.

Further, in the resin tube described above, a lead angle, which is an angle that the band-shaped portion makes with respect to a plane perpendicular to the axis of the tube body, may be 85° or more.
According to this invention, it is possible to suppress the belt-like portion from being inclined with respect to the axis of the tube body and deteriorating the appearance of the belt-like portion extending over the entire length of the tube body.

Further, in the above resin pipe, L*a* specified in JIS Z8781-4:2013 in the exposed surface of the tube main body or the outer surface of the band-shaped portion on which the indicator is provided, and the color of each of the indicators. The color difference in the b* color system may be 1 or more.
According to this invention, the exposed surface of the tube main body or the outer surface of the band-shaped portion provided with the indicator and the indicator can be easily visually recognized.

According to the resin tube of the present invention, the indicator can be easily seen.

FIG. 1 is a perspective view of a resin pipe according to an embodiment of the present invention. It is a side view of the same resin pipe. It is a side view of the resin pipe in the modification of one Embodiment of this invention. It is a figure which shows typically the manufacturing apparatus of the same resin pipe. FIG. 3 is a front view of a take-up machine of the manufacturing apparatus. It is a side view of the resin pipe in the modification of one Embodiment of this invention. It is a side view explaining the method of measuring the width of the belt-like part of the same resin pipe.

Hereinafter, one embodiment of the resin pipe according to the present invention will be described with reference to FIGS. 1 to 7.
As shown in FIGS. 1 and 2, the resin tube 1 of this embodiment includes a tube main body 11, four strips 13, and a stencil (indicator) 15. In the following figures, in order to distinguish between the tube body 11 and the strip portion 13, the strip portion 13 is shown with dot hatching.
The tube body 11 is formed into a tubular shape using polyethylene resin, which is an olefin resin. The polyethylene resin may be a high density polyethylene resin, a medium density polyethylene resin, or the like. In addition, the olefin resin may be polypropylene resin, polybutene resin, etc. in addition to polyethylene resin. Further, the olefin resin may contain inorganic fibers such as glass fibers, carbon fibers, and wollastonite. Furthermore, the tube main body 11 may be a multilayer tube in which an olefin resin layer and other layers such as a layer containing inorganic fibers or a layer containing an oxygen barrier material are laminated. When the tube main body 11 is a multilayer tube, a strip portion 13 is formed in the outermost layer for visibility. In order to connect to the electric fusion joint, it is preferable that the olefin resin layer is placed on the outer side of the other layers. is formed.
In the following description, the circumferential direction of the tube body 11 is simply referred to as the circumferential direction, and the radial direction of the tube body 11 is simply referred to as the radial direction.

The strip portion 13 is formed on the outer peripheral surface of the tube body 11. The strip portion 13 extends over the entire length of the tube body 11. In this example, each strip portion 13 is arranged along the axis C of the tube body 11. The strip portions 13 are arranged at equal angles around the axis C and spaced apart from each other.
The thickness of each strip portion 13 (the length in the radial direction of the tube body 11) is appropriately determined depending on the thickness of the tube body 11, and is preferably 0.02 mm or more and 2.0 mm or less, and 0.05 mm or more. It is more preferably 1.0 mm or less, and even more preferably 0.1 mm or more and 0.5 mm or less. By setting the thickness of each strip 13 within this range, the thickness is not too large, and the strip 13 can be removed and cut when the surface of the resin pipe 1 is cut when connected to an electric fusion joint. You can easily check what you have done. In addition, the thickness is not too small, and the color of the tube body 11 cannot be seen from the outside through the band-shaped part 13, so that the identification ability of the band-shaped part 13 can be exhibited.
The circumferential length of the band-shaped portion 13 is constant regardless of the position of the tube body 11 in the direction of the axis C.

The circumferential width of the strip portion 13 is appropriately determined according to the outer diameter of the tube body 11, and is 4 mm or more and 50 mm or less, preferably 8 mm or more and 40 mm or less. Further, the ratio of the width of the band-like portion 13 to the outer diameter of the tube body 11 is 5% or more and 30% or less, preferably 7% or more and 25% or less. The ratio of the width of the strip portion 13 to the outer diameter of the tube body 11 referred to herein means a value that is 100 times the width of the strip portion 13 divided by the outer diameter of the tube body 11. By setting the width of the band-shaped portion 13 within this range, the width is not too narrow, so that the identification ability of the band-shaped portion 13 can be exhibited no matter what direction the band-shaped portion 13 is viewed from. Furthermore, since the width is not too wide, it is possible to suppress an increase in manufacturing costs.

Note that the circumferential width of the band-shaped portion 13 can be measured using a known caliper 71, as shown in FIG. 7, for example. When the slider 73 is moved along the main body 72 of the caliper 71 and the belt-shaped portion 13 to be measured is in the state shown in FIG. 76a are made to coincide with each of the first boundary lines 13a of the strip-shaped portion 13, respectively. At this time, it is preferable that the outer measurement surfaces 75a and 76a are arranged along the axis C of the tube body 11.
The width of the strip portion 13 is measured by reading the value and scale displayed on the display section 77 of the caliper 71. The width of the strip portion 13 is defined by such a measurement method.

As shown in FIGS. 1 and 2, the exposed surface 11a of the tube body 11 that is not covered by the strip part 13 among the outer peripheral surfaces of the tube body 11 and the outer surface of the strip part 13 are flush with each other. The outer surface of the strip portion 13 is a surface of the strip portion 13 that is exposed to the outside.
In this example, the circumferential length of the exposed surface 11a of the tube body 11 is longer than the circumferential length of the outer surface of the strip portion 13. However, in the circumferential direction, the length of the exposed surface 11a of the tube body 11 and the length of the outer surface of the band-shaped portion 13 may be equal to each other or may be different from each other.
Note that the four strips 13 do not have to be arranged at equal angles around the axis C. The number of strips 13 included in the resin pipe 1 is not particularly limited, and may be one to three, or five or more.

It is preferable that the strip portion 13 is made of the same material as the tube body 11.
The color of the tube body 11 and the color of the strip portion 13 are different. The color difference (ΔE) (hereinafter simply referred to as color difference) in the L*a*b* color system defined in JIS Z8781-4:2013 in each color of the tube body 11 and the strip part 13 is 1 or more. . This color difference is preferably 5 or more, more preferably 10 or more. For example, the tube body 11 is blue and the strip 13 is red.

The color difference can be measured using a spectral color difference meter (handheld spectral color difference meter "NF333" manufactured by Nippon Denshoku Kogyo Co., Ltd.). It is preferable to measure color differences in a darkened environment such as in a dark room.
Here, the color difference (ΔE) is calculated using the following equation (1).
ΔE=√((L1-L2) ² +(a1-a2) ² +(b1-b2) ² )...(1)
In addition, in formula (1), L1, a1, and b1 represent the brightness L of the strip portion 13, the chromaticity a in the red direction, and the chromaticity b in the yellow direction, and L2, a2, and b2 represent the brightness of the tube body 11, respectively. L represents chromaticity a in the red direction and chromaticity b in the yellow direction.

The stencil 15 is provided only on the exposed surface 11a of the tube body 11 so as to extend over the entire length of the tube body 11. The stencil 15 is arranged along the axis C of the tube body 11. The stencil 15 represents, for example, the product name, model number, etc. of the resin tube 1. The stencil 15 is formed by printing using ink made of a material close to the tube body 11 or the like. For example, the stencil 15 is black, and the black stencil 15 is printed on the blue exposed surface 11a. Since the stencil 15 is not provided on the red strip 13 but only on the blue exposed surface 11a, the stencil 15 is easy to see.
The color difference between the exposed surface 11a of the tube body 11 provided with the stencil 15 and the stencil 15 is preferably 1 or more. This color difference is preferably 5 or more, more preferably 10 or more.

In addition, like the resin pipe 2 shown in FIG. The lead angle (twist angle) θ, which is the angle formed, may be 85° or more and less than 90°. Also in this case, the stencil 15 is provided only on the exposed surface 11a of the tube body 11 so as to extend over the entire length of the tube body 11. Note that when the strip portion 13 is arranged along the axis C of the tube body 11, the lead angle θ is approximately 90°.

For example, a case will be described in which the specifications of the tube body 11, the strip portion 13, and the stencil 15 are as follows. The outer diameter of the tube body 11 is 216.3 mm (nominal diameter 200A), and the length is 5 m. The width (circumferential length) of the band-shaped portion 13 is 10 mm, and the number of strips is four. The width of the stencil 15 is assumed to be 10 mm.
In this case, the distance between the strips 13 in the circumferential direction is approximately 160 mm. If the lead angle θ is less than about 88.3°, the stencil 15 will be provided not only on the exposed surface 11a of the tube body 11 but also on the outer surface of the strip portion 13, as shown by the two-dot chain line in FIG. This makes the stencil 15 difficult to see.

Next, a manufacturing apparatus for manufacturing the resin pipe 1 configured as described above will be explained.
As shown in FIG. 4, the manufacturing device 51 includes a coextrusion molding machine 52, a cooling section 53, a printing machine 55, a take-up machine 54, and a cutting machine 56. In addition, in FIG. 4, a portion forming a second flow path 52c of a molding die 52a, which will be described later, is shown by a two-dot chain line so that the inside can be easily seen.
The coextrusion molding machine 52, the cooling unit 53, the printing machine 55, the take-up machine 54, and the cutting machine 56 are operated in this order from the upstream side where the resin pipe 1 (continuous resin pipe 1A described later) is conveyed toward the downstream side. They are arranged side by side.

A first flow path 52b and a second flow path 52c are formed in a mold 52a included in the coextrusion molding machine 52. In this embodiment, four second channels 52c are formed in the molding die 52a. The four second flow paths 52c join the first flow path 52b from the side of the first flow path 52b. The resin material forming the tube body 11 is supplied in a molten state to the first channel 52b. The resin material forming the strip portion 13 is supplied in a molten state to the second flow path 52c.
A continuous resin pipe 1A is extruded downstream from the molding die 52a. The continuous resin pipe 1A is one in which resin pipes 1 are continuously connected in the direction of the axis C.
FIG. 5 shows the central axis C1 of the molding die 52a of the coextrusion molding machine 52 when viewed from the downstream side to the upstream side. In addition, in order to mainly explain the position of the central axis line C1, the molding die 52a is shown with a chain double-dashed line.

The cooling unit 53 is composed of a water tank or the like. The cooling unit 53 cools the continuous resin tube 1A formed by the coextrusion molding machine 52 using water or the like.

As shown in FIG. 5, the pulling machine 54 has a plurality of endless tracks 58. The plurality of endless tracks 58 are arranged at intervals around a predetermined central axis C2. In this example, the take-off machine 54 has four endless tracks 58.
Each endless track 58 has a plurality of holding members 59. A recess 59a is formed in the center of the holding member 59 in the width direction (circumferential direction). When a drive motor (not shown) is rotated, a portion of the endless track 58 that faces the central axis C2 moves downstream or upstream.

The endless track 58 is supported by a support member 61 and the like via a known distance adjustment mechanism 60. Each support member 61 is fixed to a frame or the like (not shown). For example, the distance adjustment mechanism 60 is provided with a lever (not shown). When the lever is rotated, the endless track 58 approaches and separates from the support member 61, and the distance between the endless track 58 and the central axis C2 is adjusted.
The distance adjustment mechanism 60 adjusts the position of the endless track 58 in the first direction D1 toward and away from the central axis C2.

The plurality of endless tracks 58 hold the continuous resin pipe 1A on the central axis C2. At this time, a part of the outer peripheral surface of the continuous resin pipe 1A enters into the recess 59a of each holding member 59 on the endless track 58. Thereby, the plurality of endless tracks 58 reliably hold the continuous resin pipe 1A. The axis C of the continuous resin tube 1A held by the plurality of endless tracks 58 is arranged on the central axis C2.
When each endless track 58 rotates in a predetermined direction, the continuous resin pipe 1A is pulled downstream.

Note that the take-up machine 54 may include a position adjustment mechanism that adjusts the position of the endless track 58 in the second direction D2, which is the tangential direction of a circle centered on the central axis C2. With this configuration, when the centers of the plurality of endless tracks 58 deviate from the central axis C2, the position adjustment mechanism and the distance adjustment mechanism 60 are used to make the centers of the plurality of endless tracks 58 coincide with the central axis C2. It can be adjusted to

The printing machine 55 prints the stencil 15 on the exposed surface 11a of the continuous resin tube 1A. The cutting machine 56 cuts the continuous resin pipe 1A into a predetermined length to form the resin pipe 1.
The resin pipe 1 is manufactured by the manufacturing apparatus 51 described above.

In the resin tube, it is preferable that the strip portion 13 is arranged along the axis C of the tube body 11 and that the lead angle θ of the strip portion 13 is about 90°. Possible causes of the lead angle θ becoming smaller than 90° due to the helical twisting of the band portion 13 include the following (1) and (2).
(1) The central axis C1 of the mold 52a of the coextrusion molding machine 52 and the central axis C2 of the take-off machine 54 are not arranged on the same straight line.
(2) Due to the difference in distance between each endless track 58 and the central axis C2, etc., there is a difference in the contact force between each endless track 58 and the continuous resin pipe 1A.

Regarding the matter (1), there is a method of measuring, for example, using a laser beam and adjusting the position so that both central axes C1 and C2 are arranged on the same straight line. The center axes C2 of the plurality of endless tracks 58 may be moved using the distance adjustment mechanism 60 and the position adjustment mechanism described above so that both center axes C1 and C2 are arranged on the same straight line. For example, it is preferable that the deviation between the central axes C1 and C2 be within 10 mm along the horizontal plane and within 10 mm in the vertical direction.
Regarding the matter (2), there is a countermeasure method in which the distance between each endless track 58 and the center axis C2 is adjusted using a lever to adjust the contact force.
By suppressing twisting of the band-shaped portion 13 in this manner, residual stress in the resin tube can be reduced.

As explained above, according to the resin tube 1 of the present embodiment, the stencil 15 is provided only on the exposed surface 11a of the tube body 11, so the exposed surface 11a of the tube body 11 and the outer surface of the strip portion 13 have different colors. The stencil 15 can be easily seen without being provided across both sides.
The stencil 15 is provided on the exposed surface 11a of the tube body 11 and on the outer surface of the strip portion 13, which is the longer exposed surface 11a in the circumferential direction. By providing the stencil 15 on the exposed surface 11a having a long circumferential length, the stencil 15 can be more easily seen on the wide exposed surface 11a.

Since the lead angle θ of the strip part 13 is 85 degrees or more, the strip part 13 is tilted with respect to the axis C of the tube body 11, and the appearance of the strip part 13 extending over the entire length of the tube body 11 is prevented from deteriorating. I can do it.
Since the color difference between the exposed surface 11a of the tube body 11 and the stencil 15 is 1 or more, the exposed surface 11a of the tube body 11 and the stencil 15 can be easily recognized visually.

Although one embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and modifications, combinations, and deletions of the configuration within the scope of the gist of the present invention. etc. are also included.
For example, in the embodiment described above, the stencil 15 may be provided only on the outer surface of one strip portion 13 so as to extend over the entire length of the tube body 11, as in the case of the resin tube 3 shown in FIG. In this case, it is preferable that the color difference between the outer surface of the band-shaped portion 13 provided with the stencil 15 and the stencil 15 is 1 or more. This color difference is more preferably 30 or more.

In the manufacturing apparatus 51, the printing machine 55 may be arranged between the take-up machine 54 and the cutting machine 56. By configuring the manufacturing device 51 in this way, it is possible to suppress the belt-shaped portion 13 from being twisted with respect to the axis C of the tube body 11.
The lead angle of the stencil 15 is preferably 85° or more, similar to the lead angle θ of the strip portion 13. In addition to the stencil 15, the index may be the name of the manufacturer of the resin pipe, letters or symbols such as cautionary notes, or the like.

Furthermore, in the embodiment described above, the strip portion 13 is integrally formed with the tube body 11 by coextrusion molding, but the method of forming the strip portion 13 is not limited to this. For example, after the tube body 11 is molded, the strip portion 13 may be formed by printing ink containing a coloring agent on the outer peripheral surface of the tube body 11.
In this case, it is preferable to print the stencil 15 at the same time as printing the strip 13 or after printing the strip 13. By manufacturing the resin tube 1 in this manner, it is possible to prevent the strip portion 13 from being printed on the stencil 15 and thereby hiding the stencil 15.

1, 2, 3 Resin pipe 11 Pipe body 11a Exposed surface 13 Band-shaped part 15 Stencil (index)
C Axis P Plane θ Lead angle

Claims (5)

A pipe body for connecting with an electric fusion joint ,
It is formed integrally with the tube body on the outer circumferential surface of the tube body so as to extend over the entire length of the tube body , and has a circumferential width of 4 mm or more and 50 mm or less per tube body, and has A band-shaped portion whose width ratio is 5% or more and 30% or less ,
an indicator provided so as to extend over the entire length of the tube body only on one of the exposed surface of the outer circumferential surface of the tube body that is not covered by the band-shaped portion and the outer surface of the band-shaped portion;
Equipped with
A resin tube in which the thickness of the band-shaped portion is 0.02 mm or more and 2.0 mm or less, and is thinner than the thickness of the tube body . The resin pipe according to claim 1, wherein the thickness of the band-shaped portion is 0.1 mm or more and 0.5 mm or less. The resin tube according to claim 1 or 2, wherein the indicator is provided on the longer circumferential length of the tube body between the exposed surface of the tube body and the outer surface of the band-shaped portion. The resin tube according to any one of claims 1 to 3, wherein a lead angle, which is an angle that the band-shaped portion makes with respect to a plane perpendicular to the axis of the tube body, is 85° or more. The color difference in the L*a*b* color system defined in JIS Z8781-4:2013 between the exposed surface of the tube body on which the index is provided or the outer surface of the band-like part and the color of each of the index is The resin pipe according to any one of claims 1 to 4, wherein the number of resin pipes is one or more.

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