JP2010221507A - Method for producing pipe with foaming material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a pipe with a foaming material where contraction of the foaming material is limited during cutting, more efficiently than conventional one. <P>SOLUTION: A crosslinked polyethylene foaming material 14 is formed into a circular form along the peripheral surface of a pipe 12, and the pipe 12 covered with the crosslinked polyethylene foaming material 14 is pulled out from a die 16 while a liner 22 is set along the peripheral surface of the crosslinked polyethylene foaming material 14. Materials are selected for respective members so as to satisfy μ0>μ1, μ2<μ3, and μ3>μ1 where μ0 denotes a friction coefficient between the die 16 and the bridge polyethylene foaming material 14, μ1 denotes a friction coefficient between the die 16 and a nylon sheet, and μ2 denotes a fiction coefficient between the crosslinked polyethylene foaming material 14 and the nylon sheet, and μ3 denotes a friction coefficient between the crosslinked polyethylene foaming material 14 and a slide suppressing layer 28. Thus, elongation of the crosslinked polyethylene foaming material 14 during pulling-out is prevented, and contraction of the foaming material during cutting is suppressed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a pipe with a foam material in which a resin foam material (heat insulating material) is coated around the resin pipe.

  In recent years, resin pipes typified by polybutene have been widely used as pipes for water supply and hot water supply, and in cold regions, a means for coating resin foams typified by polyethylene around resin pipes in particular. Has been taken.

  As a method of covering the resin pipe with a polyethylene foam (heat insulating material), cover the periphery of the resin pipe while squeezing the sheet-like foam material into a circle, and melt the end of the sheet with hot air just before it is completely covered. Then, the fused surface is joined through a hollow die having a diameter slightly smaller than the diameter after coating, and then the fused portion is cooled and solidified, and then the pipe with the foam material is compressed from the hollow die to a compression conveyor, etc. There is a method of installing and pulling out continuously.

  In the above manufacturing process, it is inevitable that friction occurs between the outer peripheral portion of the foam material and the inner surface of the hollow die. For this reason, the foam material softer than the pipe is drawn out from the hollow die in a stretched state. It is. Since the outer peripheral surface of the pipe is not bonded to the inner peripheral surface of the foam material, the pipe itself drawn from the hollow die is not stretched.

Therefore, in the pipe with a foam material obtained by such a manufacturing method, if the size of use is determined at the time of actual construction, only the foam material contracts and the phenomenon that the end of the pipe is exposed occurs. This is because the foam is stretched when it is pulled out, the tensile stress remains in the foam after pulling out, and the pipe itself is not stretched, so the foam tries to return to its original length. is there.
In view of this, a method for manufacturing a pipe with foam material that can reduce the elongation of the foam material by inserting a slippery liner between the foam material and the die has been proposed (see Patent Document 1).

JP-A-2005-125760

  By producing the pipe with the foam material by the production method described in Patent Document 1, it was possible to suppress the shrinkage of the foam material up to a certain line speed. However, if the line speed (drawing speed) is increased to increase the production efficiency, the shrinkage cannot be suppressed, and there is a limit to increasing the line speed, and there is room for improvement in the speed.

  Also, through various experimental studies, the coefficient of friction between the liner and the die is small, but the coefficient of friction with the foam is also small. Has been found to affect.

  The present invention has been made to solve the above problems, and is a method for producing a pipe with foam material, and more efficiently producing a pipe with foam material with less shrinkage of the foam material at the time of defeat. The manufacturing method of the pipe with a foaming material which can be manufactured is provided.

  The invention according to claim 1 covers the periphery of the pipe while drawing the sheet-like foam material in a circular shape, melts the sheet end portions facing each other before the foam material is completely covered, and forms the foam in the circular shape. The sheet ends melted by passing a hollow die having a diameter slightly smaller than the diameter after the coating is finished by arranging a liner on the outer surface of the material, and the sheet end from the hollow die. In the method of manufacturing a foamed pipe in which the pipe with the foamed material fused together is continuously pulled out, the liner is provided with a slip prevention layer on the foamed material side of the liner body, and the die and the foamed material Friction coefficient μ0> Friction coefficient μ1 between the die and the liner main body, Friction coefficient μ2 between the foamed material and the liner main body <Friction coefficient μ3 between the foamed material and the slip suppression layer , Said departure Coefficient of friction between the the wood slip suppressing layer .mu.3> satisfies the friction coefficient μ1 between the die and the liner body.

Next, the operation of the foamed pipe manufacturing method according to claim 1 will be described.
In the method of manufacturing a pipe with a foam material according to claim 1, since the friction coefficient μ1 between the die and the liner main body is smaller than the friction coefficient μ0 between the die and the foam material, foaming is performed without using a liner. Compared to pulling out the pipe with the material from the die, it is more effective to pull out the pipe with the foam material from the die by using the liner. The pipe with material can be pulled out. In addition, when μ1 ≧ μ0, naturally, the expansion of the foam material cannot be suppressed.

  Furthermore, according to the method for manufacturing the pipe with foam material according to claim 1, the friction coefficient μ2 between the foam material and the liner main body is smaller than the friction coefficient μ3 between the foam material and the slip suppression layer. ing. For this reason, when comparing the case where the foam material and the liner main body are in contact with the case where the foam material and the slip suppression layer are in contact, the latter (configuration of claim 1) is more preferable than the former. Since the frictional resistance between the members is large, the displacement between the foam material and the liner when the pipe with the foam material is pulled out from the die is suppressed, that is, the expansion of the foam material is suppressed by the liner. When μ2 ≧ μ3, the expansion of the foam material cannot be suppressed as compared with the conventional case.

  Further, the friction coefficient μ3 between the foam material and the slip suppression layer is set to be larger than the friction coefficient μ1 between the die and the liner body. As a result, when the pipe with foam material is pulled out of the die, the frictional resistance between the inner surface of the die and the liner main body which is the outer surface of the liner is small, and the frictional resistance between the outer surface of the foam material and the anti-slip layer on the inner surface of the liner is low. By increasing the size, the foamed pipe is smoothly pulled out from the die, and the expansion of the foamed material is suppressed by suppressing the deviation between the foamed material and the liner. When μ3 ≦ μ1, the expansion of the foam material cannot be suppressed as compared with the conventional case.

  The effect of the present invention can be obtained if at least the relationship between the friction coefficients is maintained. The materials for the die, the liner body, the anti-slip layer, and the foam material can be variously selected from various materials such as metals and synthetic resins so that the above friction coefficient relationship is maintained. Of course, a higher effect can be obtained by increasing the difference in friction coefficient.

  According to a second aspect of the present invention, in the method for manufacturing a pipe with a foam material according to the first aspect, the liner extends in a direction intersecting with the warp and a warp extending along a longitudinal direction of the pipe. A woven fabric composed of wefts.

When a fabric composed of warp and weft is pulled in a direction inclined with respect to the warp and weft, the rectangular weave is deformed into a rhombus and the fabric is easily stretched.
By setting the warp of the liner along the pipe in the direction along the longitudinal direction of the pipe, deformation of the weave can be suppressed, and the elongation of the fabric, that is, the extension of the liner itself can be suppressed.

  According to a third aspect of the present invention, in the method of manufacturing a foamed pipe according to the first or second aspect, the liner having a length of 100 mm and a width of 25 mm is pulled at 50 N in the longitudinal direction. Elongation is 0.3 mm or less.

  By setting the liner elongation to 0.3 mm or less when a liner having a length of 100 mm and a width of 25 mm is pulled in the longitudinal direction at 50 N, the liner itself can be prevented from stretching when pulled out from the die, and the liner itself can be prevented from stretching. This can further suppress the elongation of the foamed material.

  Invention of Claim 4 is a manufacturing method of the pipe with a foam material of any one of Claims 1-3. WHEREIN: The said slip suppression layer impregnated the said liner main body with the synthetic resin. It is a layer formed by.

  Since the slip suppression layer is a layer formed by impregnating the liner body with synthetic resin, the synthetic resin is firmly integrated into the liner body, making it difficult to peel off from the liner body and improving the durability of the liner To do.

As described above, according to the method for manufacturing a pipe with a foam material of the present invention, it is possible to manufacture a pipe with a foam material with less shrinkage of the foam material at the time of defeat at a higher speed than before.
According to the pipe manufacturing method of the second aspect, the expansion of the foamed material can be further suppressed. According to the pipe manufacturing method of the third aspect, the expansion of the foamed material can be further suppressed. Moreover, according to the pipe manufacturing method of the fourth aspect, the durability of the liner is improved.

It is a top view which shows schematic structure of the manufacturing apparatus used when manufacturing a pipe with a foaming material. It is a side view which shows a part of manufacturing apparatus. It is sectional drawing of dice | dies.

In FIG. 1 (A), for example, a manufacturing apparatus 10 used when manufacturing a foamed pipe 15 in which the outer periphery of a polybutene pipe 12 used for water supply in a building is covered with a crosslinked polyethylene foam material 14 as a heat insulating material. Is schematically shown in plan view.
As shown in FIGS. 1A and 1B, the cross-linked polyethylene foam material 14 is initially formed in a sheet shape cut to a certain width, but is disposed on the downstream side in the conveying direction (arrow A direction side). In front of the formed die 16, it is successively drawn into a circular shape along the outer peripheral surface of the pipe 12, and the cross-linked polyethylene foam 14 has a butt portion (edge) 14A on one side in the width direction and a butt portion (end) on the other side. Edge 14B is heated with, for example, hot air 18A from a hot air heater 18 as shown in FIG. 2, and as shown in FIG. 1, the butt portion 14A on one side and the butt portion 14B on the other side are in a molten state. Then, they are abutted and fused together to form a pipe shape that covers the outer peripheral side of the pipe 12. In addition, as the crosslinked polyethylene foam material 14 of this embodiment, a material with a polyethylene film skin is used.

  In this embodiment, before passing the pipe 12 covered with the cross-linked polyethylene foam material 14 through the hole 20 of the die 16 disposed on the downstream side in the conveying direction, a belt-like liner 22 is provided on the outer peripheral surface of the cross-linked polyethylene foam material 14. The pipe 12 covered with the crosslinked polyethylene foam material 14 is pulled out from the die 16 while the liner 22 is attached to the outer peripheral surface of the crosslinked polyethylene foam material 14 (see FIG. 1C).

  The die 16 of the present embodiment is formed of stainless steel, but may be formed of steel or other metals. A pair of transport rollers 24 for pulling out the foamed pipe 15 is disposed downstream of the dice 16 in the pipe transport direction. The conveying roller 24 is rotated in the direction of the arrow by a motor (not shown), and the pipe 15 with the foam material is sandwiched from both sides together with the liner 22 to be pulled out and conveyed from the die 16. Instead of the transport roller 24, an endless transport belt may be used.

Then, the pipe 12 with the crosslinked polyethylene foam material 14 enters the hole 20 of the die 16 with the liner 22 along the outer periphery of the crosslinked polyethylene foam material 14, and one side of the crosslinked polyethylene foam material 14 in the hole 20. The butted portion 14A and the butted portion 14B on the other side are in intimate contact with each other, and the shape as a foamed pipe is adjusted.
Thereafter, the fused portion is cooled and solidified, and is drawn to the downstream side of the die 16. The fused part may be naturally cooled or forcedly cooled.

The liner 22 of the present embodiment has an endless loop shape with a constant width so as to enter the hole 20 again after exiting from the hole 20 of the die 16.
Here, as the base material 26 of the liner 22, for example, a material that is flexible, has high tensile strength, is difficult to stretch, and has low frictional resistance with the die 16 is used. Further, the liner 22 is formed so as to have a smaller elongation than the cross-linked polyethylene foam material 14.

  As the base material 26 of the liner 22, for example, a fiber base material selected from a knitted fabric, a woven fabric, a non-woven fabric and the like can be used. Examples of the fiber material constituting the fiber base include natural fibers such as cotton and hemp, inorganic fibers such as metal fibers and glass fibers, polyamide, polyester, polyethylene, polyurethane, polystyrene, polyfluoroethylene, polyacryl, and polyvinyl. Any of organic chemical fibers such as alcohol and aromatic polyamide can be used alone or in combination.

As shown in FIG. 3, a nylon sheet is used for the base material 26 of the liner 22 of the present embodiment, and the nylon sheet has a cross-linked polyethylene foam 14 and a side in contact with the cross-linked polyethylene foam 14. An anti-slip layer 28 is provided for the purpose of increasing the friction coefficient between the two.
The nylon sheet of the present embodiment includes a warp composed of nylon fibers extending along the circumferential direction of the liner 22 (which becomes the longitudinal direction of the pipe 12 when the liner 12 is aligned), and nylon fibers extending in a direction intersecting the warp. A plain woven fabric composed of weft yarns.
The slip suppression layer 28 of the present embodiment is a layer formed by impregnating one side of a nylon sheet with a synthetic resin. In the slip suppression layer 28, nylon fibers are embedded in the synthetic resin. . By impregnating the nylon sheet with synthetic resin, the synthetic resin enters the gap between the fibers of the nylon sheet and integrates with the fiber, increasing the contact area between the synthetic resin and the nylon sheet (fiber), and the synthetic resin is nylon. The structure is difficult to peel off from the sheet.

  Here, the coefficient of friction between the die 16 and the cross-linked polyethylene foam 14 is μ0, the coefficient of friction between the die 16 and the nylon sheet is μ1, and the coefficient of friction between the cross-linked polyethylene foam 14 and the nylon sheet is μ2. The die 16 and the cross-linked polyethylene foam material satisfy all of μ0> μ1, μ2 <μ3, and μ3> μ1 when the friction coefficient between the cross-linked polyethylene foam material 14 and the slip suppression layer 28 is μ3. 14, the material of the base material 26 of the liner 22 and the slip suppression layer 28 are selected.

  The cross-linked polyethylene foam material 14 may have a polyethylene film formed on the surface thereof. Instead of the crosslinked polyethylene foam material 14, a resin foam material typified by polypropylene, polystyrene, phenol, polyurethane or the like can be used. Of course, foam materials listed in JIS A9511 are used as the foam material.

  The thickness of the crosslinked polyethylene foam material 14 is not particularly specified, but when the pipe 12 is used for water supply / hot water supply in a building, 3 to 20 mm is a preferable range. The outer diameter of the pipe 12 is not particularly limited, but in the case of water supply / hot water supply for buildings, for example, φ12 to 30 mm, and there may be a larger diameter.

For the slip suppression layer 28, a resin material or the like that satisfies the magnitude relationship of the friction coefficient as described above is selected. As a resin material used for the slip suppression layer 28, a material having a large friction coefficient is preferable, and a known elastomer or the like can be used. For example, thermoplastic resins such as thermoplastic urethane, polyvinyl chloride, and thermoplastic olefin, urethane rubber Further, rubber such as ethylene propylene rubber or a mixture thereof is appropriately used.
Note that a thermoplastic urethane resin is used for the slip suppression layer 28 of the present embodiment.

  Although a nylon sheet is used for the liner 22, for example, an acrylic liner, a polyester liner, a vinylon liner, a glass fiber liner, a nonwoven fabric, or the like may be used. However, those having a small elongation in the circumferential direction of the liner are preferred. The thickness of the liner 22 is preferably about 1/5 to 1/20 of the thickness of the cross-linked polyethylene foam material 14, and if it is too thick, it acts to compress the cross-linked polyethylene foam material 14, and the cross-linked polyethylene foam material 14 In some cases, the fusion strength of the fused surface may be reduced. The actual dimension of the thickness of the liner 22 is preferably in the range of 0.1 to 3 mm.

Next, the effect | action of the manufacturing method of the pipe with a foam material of this embodiment is demonstrated.
First, the friction coefficient μ1 between the die 16 and the base material 26 is set to be smaller than the friction coefficient μ0 between the die 16 and the crosslinked polyethylene foam material 14. Therefore, as compared with the case where the foamed pipe 15 is pulled out from the die 16 without using the liner 22, the frictional resistance with the inner surface of the die 16 is greater when the foamed pipe 15 is pulled out from the die 16 using the liner 22. And the foamed pipe 15 can be pulled out while suppressing the elongation of the cross-linked polyethylene foam 14.

  Further, the friction coefficient μ2 between the crosslinked polyethylene foam 14 and the base material 26 is set to be smaller than the friction coefficient μ3 between the crosslinked polyethylene foam 14 and the slip suppression layer 28, When the case where the material 26 is in contact with the case where the crosslinked polyethylene foam material 14 and the anti-slip layer 28 are in contact is compared, the latter, the configuration of this embodiment, has a friction between members. Resistance increases. Therefore, the displacement between the crosslinked polyethylene foam 14 and the liner 22 when the pipe 15 with the foam material is pulled out from the die 16 is suppressed, and the elongation of the crosslinked polyethylene foam 14 is suppressed by the liner 22, thereby further increasing the elongation. Will be suppressed.

  Furthermore, in this embodiment, since the friction coefficient μ3 between the crosslinked polyethylene foam 14 and the slip suppression layer 28 is set larger than the friction coefficient μ1 between the die 16 and the base material 26, foaming is performed. When the pipe 15 with material is pulled out from the die 16, the frictional resistance between the inner surface of the die 16 and the liner main body serving as the outer surface of the liner 22 is small, and the slip suppression layer 28 on the outer surface of the crosslinked polyethylene foam 14 and the inner surface of the liner 22. The foamed pipe 15 is smoothly pulled out from the die 16 and the displacement between the crosslinked polyethylene foam 14 and the liner 22 is suppressed, so that the crosslinked polyethylene foam 14 at the time of withdrawal is increased. Is further suppressed.

  As described above, the effect of suppressing the elongation of the crosslinked polyethylene foam material 14 by reducing the friction with the die 16 at the time of drawing and the elongation of the crosslinked polyethylene foam material 14 by increasing the friction between the liner 22 and the crosslinked polyethylene foam material 14. The effect of suppressing the deviation between the liner 22 and the cross-linked polyethylene foam material 14 that causes the above-mentioned causes can be more effectively suppressed than the conventional case, and the elongation of the cross-linked polyethylene foam material 14 during pulling can be effectively suppressed. The shrinkage of the crosslinked polyethylene foam 14 after cutting can be effectively suppressed, and the drawing speed (line speed) of the pipe 15 with foam can be increased, thereby improving the production efficiency of the pipe 15 with foam. Can be made.

  In addition, when the base material 26 is a woven fabric, it is configured to include a warp arranged in a circumferential direction (a direction extending along the longitudinal direction of the pipe 12 at the time of drawing) and a weft extending in a direction crossing the warp. It is preferable to use a woven fabric. This is because when a fabric composed of warp and weft is pulled in a direction inclined with respect to the warp and weft, the rectangular weave is deformed into a rhombus and the fabric easily extends. The deformation of the weave is suppressed, and the elongation of the fabric itself, that is, the extension of the liner 22 itself is suppressed.

Moreover, it is preferable that the liner 22 itself does not easily stretch. For example, it is preferable that the elongation when the length of 100 mm and the width of 25 mm is pulled at 50 N in the longitudinal direction is 0.3 mm or less. Thereby, the elongation of the crosslinked polyethylene foam 14 can be effectively suppressed.
Furthermore, since the liner 22 of this embodiment impregnates a nylon sheet with a thermoplastic urethane resin, the thermoplastic urethane resin is hardly peeled off from the nylon sheet and is a highly durable liner 22.

[Other Embodiments]
In order to quickly solidify the melted portion, a rapid cooling zone (4 to 15 ° C., preferably 5 to 10 ° C.) for forcibly cooling may be provided in the latter half of the die 16. .
In the above embodiment, the butted portions 14A and 14B of the cross-linked polyethylene foam material 14 are melted by the hot air of the hot air heater 18, but a contact heater such as an electric heating iron that is brought into contact with the butted portions 14A and 14B is newly installed to heat the electric heating iron. And the hot air of the hot air heater 18 may melt the abutting portions 14A and 14B, or the abutting portions 14A and 14B may be melted using only the heat of an electric heating iron.
In the above embodiment, the butted portions 14A and 14B of the crosslinked polyethylene foam material 14 are melted and joined. For example, the butted portions 14A and 14B may be joined using a hot melt adhesive or the like.
In the present invention, as long as the relationship between the friction coefficients μ0 to μ3 between the members is satisfied, the material of each member is not limited to that of the above embodiment, and various modifications can be made without departing from the gist of the present invention. Is possible.

[Test example]
In order to confirm the effect of the present invention, a liner consisting only of a nylon sheet and a liner provided with a urethane resin layer on one side of the nylon sheet are prepared, and the drawing speed (so-called line speed) of the foamed pipe is variously changed. The produced foamed pipe was cut at a certain length (for example, 5 m), and the shrinkage ratio (%) of the crosslinked polyethylene foamed material was measured.
The pipe used here was a φ17 mm polybutene pipe, and a 5 mm thick crosslinked polyethylene foam was used. The liner used had a thickness of 1.5 mm and covered 80% of the outer surface of the crosslinked polyethylene foam.
The measurement results are as shown in Table 1 below.

試験結果から分かるように、ナイロンシートの片面に滑り抑制層を設けたライナーを用いることにより、製造された発泡材付きパイプのポリエチレン発泡材の縮み率は極めて小さく、ラインスピードを高速化でき、発泡材付きパイプの生産効率の向上を図ることができる。

As can be seen from the test results, by using a liner with a slip prevention layer on one side of the nylon sheet, the shrinkage rate of the polyethylene foam material of the manufactured pipe with foam material is extremely small, the line speed can be increased, and foaming is achieved. The production efficiency of pipes with materials can be improved.

DESCRIPTION OF SYMBOLS 10 Manufacturing apparatus 12 Pipe 14 Crosslinked polyethylene foam 14A Butt part 14B Butt part 15 Pipe with foam 16 Die 20 Hole 22 Liner 24 Conveying roller 26 Base material 28 Slip prevention layer

Claims (4)

Cover the periphery of the pipe while squeezing the sheet-like foam material into a circle, melt the sheet ends facing each other before the foam material is completely covered, and place a liner on the outer surface of the foam material squeezed into a circle With a foam material in which the sheet ends melted by passing through a hollow die having a diameter slightly smaller than the diameter after the coating is completed, and the sheet ends are fused from the hollow die In the manufacturing method of the pipe with the foam material that pulls out the pipe continuously,
The liner is provided with a slip suppression layer on the foam material side of the liner body,
Friction coefficient μ0 between the die and the foam material> Friction coefficient μ1 between the die and the liner body,
Friction coefficient between the foamed material and the liner body μ2 <Friction coefficient μ3 between the foamed material and the slip suppression layer,
A method for manufacturing a pipe with foam material satisfying a friction coefficient μ3 between the foam material and the slip suppression layer> friction coefficient μ1 between the die and the liner body.   2. The method for producing a pipe with foam material according to claim 1, wherein the liner is a woven fabric including warps extending along a longitudinal direction of the pipe and wefts extending in a direction crossing the warp. .   The manufacturing method of the pipe with a foam material according to claim 1 or 2, wherein the liner elongation when the liner having a length of 100 mm and a width of 25 mm is pulled at 50 N in a longitudinal direction is 0.3 mm or less.   The said slip suppression layer is a manufacturing method of the pipe with a foam material of any one of Claims 1-3 which is a layer formed by making the said liner main body impregnated with a synthetic resin.

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