JP2016194359A - Heat insulation piping system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat insulation piping system which finely keeps a high heat insulation effect.SOLUTION: A heat insulation piping system 100 includes resin piping 200, a heat insulation fiber layer 400 and a coating layer 510. The heat insulation fiber layer 400 coats an outer peripheral surface of the resin piping 200. The heat insulation fiber layer 400 includes a skin layer 410 on a surface on the resin piping. The coating layer 510 coats an outer peripheral surface of the heat insulation fiber layer 400. The resin piping 200 is thus coated by the heat insulation fiber layer 400, a high heat insulation effect can be obtained. Further, since the heat insulation fiber layer 400 includes the skin 410 layer on the surface on the rein piping 200 side, air contacting with the outer peripheral surface of the resin piping 200 is decreased, and dew formation can be suppressed. Furthermore, the coating layer 510 coats the outer peripheral surface of the heat insulation fiber layer 400, thereby preventing wetness from the outer peripheral side of the heat insulation fiber layer 400 and suppressing the permeation of air including moisture. Therefore, a high heat insulation property is finely kept.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat insulating piping system. More specifically, this invention relates to the heat insulation piping system with which the heat insulation effect is maintained favorable.

  Conventionally, metal piping, particularly carbon steel pipe (SGP) for piping has been mainly used as piping material for cooling / heating water of an air conditioning fan coil. However, the piping system using metal piping has problems of rust resistance and seismic resistance (strain resistance) due to the characteristics of the material, piping workability due to being heavy, and securing of building strength. There is.

  On the other hand, among resin pipes, resin pipes can solve the problems of rust resistance, earthquake resistance, pipe workability, and building strength securing. For this reason, attempts have been made to replace metal piping with resin piping. For example, JP 2002-256024 A (Patent Document 1) has characteristics such as rigidity, creep characteristics, impact strength, pressure resistance, heat resistance, wear resistance, flexibility, and crystallization speed. Furthermore, a pipe material for cold / hot water made of a polybutene resin excellent in balance between moldability, particularly high-speed moldability of a small-diameter pipe and pressure resistance is disclosed.

JP 2002-256024 A

  The pipe material for cold / hot water of the above polybutene resin has heat resistance characteristics, and the heat resistance is characteristics of the resin itself. Therefore, the piping system has only a slight effect of improving heat resistance, and for example, a high degree of heat insulation that prevents the occurrence of condensation is not achieved.

  In order to significantly improve the heat insulation of the piping system, the present inventors have adopted a means for covering the surface of the resin-made cold / hot water piping with a fibrous heat insulating material. The heat insulating material has a large specific surface area and exhibits a lot of air in order to exert its characteristics. Therefore, the heat insulating material brings a large amount of air into contact with the pipe surface to exhibit heat insulating properties. However, when cold water is caused to flow through the pipe, the air condenses depending on the temperature of the air in contact with the pipe surface. When the heat insulating material gets wet due to condensation, the heat insulating effect decreases. In particular, in the case of a fibrous heat insulating material having air permeability, an environment in which dew condensation is repeated occurs, so that the heat insulating property is seriously deteriorated due to wetting of the heat insulating material.

  Therefore, the objective of this invention is providing the heat insulation piping system by which a high degree heat insulation effect is maintained favorable.

  In order to achieve the above object, the present invention includes the following inventions.

(1)
The heat insulation piping system of this invention contains resin piping, a heat insulation fiber layer, and a coating layer. The heat insulating fiber layer covers the outer peripheral surface of the resin pipe. Furthermore, the heat insulating fiber layer includes a skin layer on the surface on the resin piping side. The coating layer covers the outer peripheral surface of the heat insulating fiber layer.

Thus, since resin piping is coat | covered with the heat insulation fiber layer, the high heat insulation effect is acquired. Furthermore, since the heat insulating fiber layer includes the skin layer on the surface on the resin piping side, the air contacting the outer peripheral surface of the resin piping is reduced, and the occurrence of condensation can be suppressed. Furthermore, the coating layer covers the outer peripheral surface of the heat insulating fiber layer, thereby preventing wetting from the outer peripheral surface side of the heat insulating fiber layer and suppressing the permeation of air containing moisture.
Therefore, a high degree of heat insulation is well maintained by the above configuration.

The resin pipe is used as a pipe for flowing at least cold water.
The skin layer is a layer constituting the inner peripheral surface of the heat-insulating fiber layer. Specifically, the skin layer can be embodied by at least one of relatively increasing the fiber density and containing a binder resin. it can.

(2)
The average density of the heat insulating fiber layer may be 20 kg / m ³ or more and 100 kg / m ³ or less.
With this configuration, a good heat insulating effect can be obtained.

(3)
The heat insulating fiber layer may include a plurality of thin tubular layers having a density higher than the average density in a substantially concentric manner.

  With this configuration, since there are many layers with high fiber density in the radial direction inside the heat insulating fiber layer, it is difficult to transmit air in the radial direction. Accordingly, it is possible to further suppress the progress of condensation.

(4)
The resin pipe may be a multilayer pipe including a first layer, a second layer, and a third layer in the direction from the axial center to the outer periphery. In this case, the first layer is a thermoplastic resin, the second layer is a thermoplastic resin containing fibers, and the third layer is a thermoplastic resin.

This configuration is particularly useful when the resin pipe is a pipe through which cold / hot water flows.
Resin piping inherently has a larger coefficient of linear expansion than metal piping, so thermal expansion and contraction due to the flow of cold / hot water in the piping is large. Is suppressed, and the dimensional stability is excellent. Therefore, even when cold / hot water flows in the piping, gaps or distortions at the joints of the heat-insulating fiber layers can be preferably prevented. For this reason, the stable heat insulation effect can be acquired in a wide temperature range.

(5)
It is preferable that the fiber diameter of the fibers contained in the second layer is larger than the fiber diameter of the fibers constituting the heat insulating fiber layer.

  With this configuration, in the heat insulating fiber layer in which thinner fibers are used, the thin fibers tend to intertwine and easily form an air phase. It has preferred strength and rigidity.

(6)
The fiber diameter of the fibers constituting the heat insulating fiber layer is preferably 5 μm or more and 10 μm or less, and the fiber diameter of the fibers contained in the second layer is preferably 12 μm or more and 50 μm or less.

  With this configuration, the heat insulating fiber layer has more preferable heat insulating properties, while the second layer of the resin pipe has more preferable strength and rigidity.

(7)
It is preferable that the fiber length of the fiber contained in the second layer is larger than the fiber length of the fiber constituting the heat insulating fiber layer.

  With this configuration, in the heat-insulating fiber layer in which longer fibers are used, the shape in which the long fibers are entangled is less likely to be collapsed, and the heat insulation that is preferably maintained can be achieved. Two layers have good moldability and are easy to control the orientation of short fibers.

(8)
The fiber length of the fibers constituting the heat insulating fiber layer is preferably more than 5 mm, and the fiber length of the fibers contained in the second layer is preferably 5 mm or less.

  With this configuration, the shape in which long fibers are entangled in the heat insulating fiber layer is less likely to collapse, and more preferably maintained heat insulating properties can be achieved, whereas the second layer of the resin pipe has better moldability. At the same time, it is easier to control the orientation of short fibers.

  In addition, although the upper limit contained in the range of the fiber length of the fiber which comprises a heat insulation fiber layer is not specifically limited, For example, it may be 15 mm. Further, the lower limit value included in the fiber length range of the fibers included in the second layer is not particularly limited, but the fiber length of the fibers included in the second layer is, for example, 0.10 mm or more from the viewpoint of strength and rigidity. It is preferable.

(9)
When the relative thickness of the first layer is 1, the relative thickness of the second layer is preferably 2 or more and 6 or less, and the relative thickness of the third layer is preferably 0.5 or more and 2 or less.

  With this configuration, thermal expansion and contraction of the resin pipe can be preferably suppressed, and excellent dimensional stability can be achieved. Therefore, a more stable heat insulating effect can be obtained in a wide temperature range.

(10)
The fiber content in the second layer is preferably 10% by weight or more and 60% by weight or less when the entire resin composition for producing the second layer is 100% by weight.

  With this configuration, it is possible to provide good moldability while preferably providing dimensional stability.

(11)
The ten-point average roughness Rz of at least one of the interface between the first layer and the second layer and the interface between the second layer and the third layer is preferably 30 μm or more.

With this configuration, since the layer interface is sufficiently rough, even if the resin piping is deformed, the interface peeling is unlikely to occur. In the present specification, the deformation that the resin pipe can undergo includes deformation due to external force load, deformation due to environmental changes such as temperature change, humidity change, and aging deterioration.
The upper limit value included in the range of the ten-point average roughness Rz is not particularly limited, but is, for example, 300 μm from the viewpoint of ease of manufacture. The ten-point average roughness Rz is a measured value based on JIS B 0601.

(12)
In the heat insulation piping system of (1) to (3) above, the resin piping may be made of a polyolefin resin, and the coating layer may be made of a polyolefin resin.

  With this configuration, the resin piping has good flexibility and excellent earthquake resistance, and the mechanical properties of the resin piping and the coating layer are uniform. By doing so, the wetting prevention effect from the outer peripheral surface side of a heat insulation fiber layer and the permeation | transmission suppression effect of the air containing moisture can be maintained stably.

It is a partially cutaway sectional view of the heat insulation piping system of a 1st embodiment. It is a typical sectional view of the heat insulation piping system of Drawing 1, and its partially expanded view. It is a typical sectional view of the heat insulation piping system of a 2nd embodiment, and its partially expanded view. It is a typical sectional view of resin piping in the heat insulation piping system of a 3rd embodiment. It is a typical sectional view of the 1st modification of resin piping in the heat insulation piping system of a 3rd embodiment. FIG. 6 is a partially enlarged view of FIG. 5. It is a typical sectional view of the 2nd modification of resin piping in the heat insulation piping system of a 3rd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same elements are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[First Embodiment]
FIG. 1 is a partially cutaway cross-sectional view of the heat insulation piping system of the first embodiment. 2 is a schematic cross-sectional view of the heat insulating piping system of FIG. 1 and a partially enlarged view thereof.
The heat insulating piping system 100 shown in FIGS. 1 and 2 includes a resin piping 200, a heat insulating fiber layer 400, and a coating layer 510. As shown in FIG. 1, the heat insulating piping system 100 can further include a decorative sheet 520 and a restraining member 530 (these elements are omitted in FIG. 2).

[Resin piping 200]
The resin pipe 200 is a pipe used for a cold / hot water pipe, a water and sewage pipe, and the like. The resin pipe 200 is mainly composed of a polyolefin resin. As a result, the piping itself has flexibility and good earthquake resistance can be obtained.

  The polyolefin resin is not particularly limited. Examples thereof include polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer. From the viewpoint of effectively increasing the strength of the molded article or the elongation at high temperature, it is preferably selected from polyethylene, polypropylene and polybutene, more preferably polyethylene.

Furthermore, examples of polyethylene (PE) include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE). Examples of polypropylene (PP) include homo PP, block PP, and random PP. Examples of polybutene include polybutene-1. The ethylene-α-olefin copolymer is about several mol% of α-olefin such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene or 1-octene with respect to ethylene. It is preferable that the copolymer is copolymerized at a ratio of
One of these polyolefin resins may be used alone, or two or more thereof may be used in combination.

  The resin pipe 200 may have a single layer structure or a multilayer structure. The resin constituting the resin pipe 200 (in the case of a multilayer structure, the resin constituting a part of the layers) may be a fiber reinforced resin (described later) or a foamed resin.

The resin pipe 200 is connected by a joint (not shown). The joint is also preferably composed mainly of a polyolefin resin. As a result, since the connecting portion of the piping is also flexible, for example, even if a force that shifts the axial directions of the resin piping 200 connected to each other due to an earthquake or the like is applied, the joint is bent and both the resin piping 200 deviations can be followed. Therefore, earthquake resistance can be obtained as the entire heat insulating piping system 100.
As will be described later, the outer peripheral surface of the illustrated resin pipe 200 is covered many times, but the outer peripheral surfaces of the joints connecting the resin pipes 200 are also similarly covered without being distinguished.

[Insulating fiber layer 400]
The heat insulating fiber layer 400 covers the entire outer peripheral surface of the resin pipe 200. In FIG. 1, two heat insulating fiber layers 400 are joined to one resin pipe 200 in the axial direction. The heat-insulating fiber layer 400 is not particularly limited as long as the fibers are entangled three-dimensionally so as to contain a large amount of air and have a large specific surface area. For example, inorganic fibers are preferably employed as the heat insulating fiber layer 400 from the viewpoint of preventing the spread of fire. Specific examples of the inorganic fiber include glass fiber, ceramic fiber, and artificial mineral fiber. The fibers are preferably non-woven from the viewpoint of containing a large amount of air.

The average density of the heat insulating fiber layer 400 is, for example, 20 kg / m ³ or more and 100 g / m ³ or less, preferably 45 kg / m ³ or more and 90 kg / m ³ or less. Thereby, a good heat insulating effect can be obtained. The thickness of the heat insulating fiber layer 400 may be 2% or more and 400% or less, preferably 5% or more and 350% or less, more preferably 15% or more and 135% or less of the outer periphery radius of the resin pipe 200. Thereby, a good heat insulating effect can be obtained.

  Although the fiber diameter of the fiber which comprises the heat insulation fiber layer 400 is not specifically limited, For example, they are 5 micrometers or more and 10 micrometers or less. It is easy to maintain a shape in which fibers are entangled three-dimensionally by being an appropriate thickness not less than the above lower limit value, and it is easy to efficiently form an air phase by being an appropriate fineness not more than the above upper limit value. Therefore, preferable heat insulation can be provided. The fiber diameter is the average of the maximum diameters of the cross sections of the fibers constituting the heat insulating fiber layer 400.

  Although the fiber length of the fiber which comprises the heat insulation fiber layer 400 is not specifically limited, For example, it exceeds 5 mm, Preferably it is 7 mm or more, More preferably, it is 9 mm or more. As a result, the shape in which the fibers are entangled is unlikely to collapse, and the heat insulating property that is preferably maintained can be provided. Although the upper limit contained in the range of the fiber length which comprises a heat insulation fiber layer is not specifically limited, For example, 20 mm, Preferably it may be 15 mm. The fiber length is an average of the lengths of the fibers constituting the heat insulating fiber layer 400.

  The heat insulating fiber layer 400 includes a skin layer 410 that contacts the outer peripheral surface of the resin pipe 200 and a heat insulating layer 420 that occupies other portions. The skin layer 410 only needs to be configured to reduce the air in contact with the outer peripheral surface as compared with the case where the heat insulating layer 420 directly contacts the outer peripheral surface of the resin pipe 200. That is, the skin layer 410 is configured to have a specific surface area smaller than that of the heat insulating layer 420. Thereby, the air which contacts the outer peripheral surface of the resin pipe 200 is reduced, and the occurrence of condensation can be suppressed.

  The skin layer 410 may be embodied by, for example, increasing the fiber density than the heat insulating layer 420, including a binder resin, or increasing the fiber density and including the binder resin than the heat insulating layer 420. it can.

When the fiber density of the skin layer 410 is larger than the fiber density of the heat insulating layer 420, it is preferable that the skin layer 410 has a higher density than the average density of the heat insulating fiber layer 400. In this case, for example, the average density of the heat-insulating fiber layer 400 may be 1.1 to 3 times, or 22 kg / m ^{3 to} 300 kg / m ³ , preferably 26 kg ^{3 to} 300 kg / m ³ , More preferably, it may be 50 kg / m ³ or more and 300 kg / m ³ or less. More preferably, the skin layer 410 has a specific surface area that is small enough to prevent air from passing therethrough. As a result, the surface of the skin layer 410 becomes smoother and can easily follow the outer surface of the resin pipe 200, and air contacting the outer peripheral surface of the resin pipe 200 is eliminated as much as possible, and the occurrence of condensation can be more preferably suppressed.

  When the binder resin is contained in the skin layer 410, the binder resin coats the surface of the fiber so that the binder resin is interposed between the fibers. Accordingly, the specific surface area is reduced by reducing the distance between the fibers. Alternatively, the binder resin stably maintains the smoothness of the surface of the skin layer 410 by fixing the state in which the fibers are compressed and the specific surface area is reduced so that the surface of the skin layer 410 is smooth. It does not specifically limit as binder resin, For example, thermosetting resins, such as a phenol resin, are mentioned.

  The thickness of the skin layer 410 may be 0.3 mm or more and 7 mm, for example. It is preferably 0.3 mm or more from the viewpoint that the outer peripheral surface of the resin pipe 200 can be sufficiently covered, and it is preferably 7 mm or less from the viewpoint of maintaining good heat insulation performance as the heat insulating fiber layer 400 as a whole. From the viewpoint of effectively suppressing the progress of condensation by reducing the amount of air in the vicinity of the outer surface of the resin pipe 200 and reducing the amount of moisture contained in the air, the thickness of the skin layer 410 is more preferably 0.00. It is 5 mm or more and 6 mm or less, More preferably, it is 1 mm or more and 5 mm or less.

[Coating layer 510]
The covering layer 510 covers the entire surface of the heat insulating fiber layer 400. Thus, wetting from the outer peripheral surface side of the heat insulating fiber layer 400 is prevented and permeation of air containing moisture is suppressed. As shown in FIG. 1, the covering layer 510 also shields the joint S of the heat insulating fiber layer 400 joined in the axial direction. Thereby, the inflow of air containing moisture from the joint S is also suppressed.

  The material of the covering layer 510 may be any non-permeable material. Specifically, a non-foamed resin, that is, a solid resin is preferable. By covering the surface of the heat-insulating fiber layer 400 with such a non-water-permeable covering layer 510, the heat-insulating fiber layer 400 can be waterproofed and deterioration of heat-insulating property due to wetting can be prevented.

  Furthermore, when the resin pipe 200 is made of a polyolefin resin, it is more preferable that the material of the coating layer 510 is also a polyolefin resin. Thereby, since the mechanical characteristics of the resin pipe 200 and the covering layer 510 are uniform, when the resin pipe 200 thermally expands and contracts, the covering layer 510 also expands and contracts in the same manner, so It is possible to stably maintain the wet prevention effect and the permeation suppression effect of air containing moisture.

  As polyolefin resin which may comprise the coating layer 510, what was illustrated above as resin which comprises the resin piping 200 can be used, without specifically limiting. The polyolefin resin constituting the resin pipe 200 and the polyolefin resin constituting the coating layer 510 may be the same or different.

[Decorative sheet 520, restraining member 530]
The decorative sheet 520 covers the entire surface of the covering sheet 510. As a result, good appearance can be obtained. The decorative sheet 520 preferably has a metal film. The decorative sheet 520 may have a form in which a metal film is laminated on one surface of a base material. In this case, the substrate may be coated so as to be on the coating sheet 510 side, or the metal film may be coated so as to be on the coating sheet 510 side. In addition, the decorative sheet 520 may have a sandwich shape in which metal films are laminated on both sides of the base material.
More specifically, the decorative sheet 520 includes an aluminum glass cloth (ALGC) in which aluminum foil and glass cloth are bonded together, an aluminum craft (ALK) in which aluminum foil and craft paper are bonded together, and aluminum foil and split cloth. And aluminum split cloth (ALW).

  The surface of the decorative sheet 520 is covered with a restraining member 530. Thereby, the heat insulation fiber layer 400, the coating layer 510, and the decorative sheet 520 laminated | stacked on the resin piping 200 can be restrained stably. The restraining member 530 can also prevent the decorative sheet 520 from peeling off. Restraint member 530 may be made of resin or metal, but is preferably made of metal from the viewpoint of fire resistance. The restraining member 530 is not particularly limited as long as the restraining member 530 has a shape capable of restraining the heat insulating fiber layer 400 and the decorative sheet 520 and protecting the decorative sheet surface, but in this embodiment, a mesh sheet is used.

[Construction]
The heat insulation piping system 100 may be constructed as follows.
The resin pipe 200 is appropriately connected by a joint, and is fixed to a fixed base at an appropriate position. The heat insulating fiber layer 400 is covered on the outer peripheral surface of the resin pipe 200. The heat insulating fiber layer 400 can be externally mounted on the resin pipe 200 using a heat insulating fiber molded product that is formed into an annular shape that is cut to a predetermined length and that is cut in the axial direction.

After the heat insulating fiber layer 400 is packaged on the resin pipe 200, the surface of the heat insulating fiber layer 400 is integrally covered with the covering layer 510. The covering layer 510 can be wound around the surface to be covered, for example, while delivering the sheet from a roll wound with a long resin sheet. In particular, the resin sheet is wound so as to completely shield the joint S of the heat insulating fiber layer 400.
After the covering layer 510 is provided, the decorative sheet 520 is wound around the entire surface of the covering layer 510 and then the restraining member 530 is wound.

[Other Embodiments]
Hereinafter, 2nd Embodiment from which the aspect of a heat insulation fiber layer differs, and 3rd Embodiment from which the aspect of resin piping differs are described. In these other embodiments, differences from the first embodiment are basically described, and descriptions of similar points are omitted.

[Second Embodiment]
FIG. 3 is a schematic cross-sectional view of the heat insulation piping system of the second embodiment and a partially enlarged view thereof, and corresponds to FIG. 2 of the first embodiment. 3 includes a resin pipe 200, a heat insulating fiber layer 400a, and a coating layer 510. The heat insulating pipe system 100a shown in FIG. In addition, although illustration is abbreviate | omitted, similarly to 1st Embodiment, the decorative sheet 520 and the restraint member 530 can be included further,

[Insulating fiber layer 400a]
The heat insulating fiber layer 400a includes a skin layer 410 positioned on the resin pipe 200 side, a plurality of thin layers 430, and a heat insulating layer 420 filling the space therebetween. The thin layer 430 is formed substantially concentrically with the skin layer 410. Similar to the skin layer 410, the thin layer 430 is configured to have a specific surface area smaller than that of the heat insulating layer 420. Thereby, since there are many layers (thin layers 430) having a small specific surface area in the radial direction inside the heat insulating fiber layer 400a, it is difficult to transmit air in the radial direction. Therefore, the progress of dew condensation on the outer surface of the resin pipe 200 can be further suppressed.

  The thin layer 430 is realized by making the fiber density larger than that of the heat insulating layer 420, containing a binder resin, or making the fiber density larger than that of the heat insulating layer 420 and containing a binder resin.

When the fiber density of the thin layer 430 is larger than the fiber density of the heat insulation layer 420, it is preferable that it is larger than the average density of the heat insulation fiber layer 400a. In this case, for example, the average density of the heat insulating fiber layer 400a may be 1.1 to 3 times, or 22 kg / m ^{3 to} 300 kg / m ³ , preferably 26 kg ^{3 to} 300 kg / m ³ , More preferably, it may be 50 kg / m ³ or more and 300 kg / m ³ or less. More preferably, the thin layer 430 has a specific surface area that is small enough to prevent air from passing therethrough. This makes it more difficult for air to penetrate more in the radial direction. Therefore, the progress of dew condensation on the outer surface of the resin pipe 200 can be further suppressed.

  When the binder resin is contained in the thin layer 430, the binder resin is coated between the fibers by coating the surface of the fibers with the binder resin. Accordingly, the specific surface area is reduced by reducing the distance between the fibers. Alternatively, the binder resin stably maintains a relatively high fiber density in the thin layer 430 by fixing the state in which the fibers are compressed and the specific surface area is reduced. It does not specifically limit as binder resin, For example, thermosetting resins, such as a phenol resin, are mentioned.

  The thickness of the thin layer 430 may be 0.3 mm or more and 7 mm, for example. It is preferable that it is 0.3 mm or more from the viewpoint that the inside of the heat insulating fiber layer 400a can be sufficiently partitioned, and that it is 7 mm or less is preferable from the viewpoint of maintaining good heat insulating performance as the whole heat insulating fiber layer 400a. From the viewpoint of making air difficult to permeate in the radial direction, the thickness of the thin layer 430 is more preferably not less than 0.5 mm and not more than 6 mm, and further preferably not less than 1 mm and not more than 5 mm.

[Manufacture of heat insulating fiber layer]
The heat insulating fiber layers 400 and 400a can be manufactured as follows, for example. First, glass wool is hot-pressed and formed into a sheet (Step 1). Then, the glass wool sheets are concentrically stacked many times (preferably, the long glass wool sheets are wound many times) to form a thick cylindrical member (step 2). Further, the glass wool sheets that overlap each other are fixed (step 3). In fixing in step 3, it may be baked and hardened by heat, or may be bonded using a binder resin. When a binder resin is used, it is preferably water-resistant.

  The skin layer 410 can be formed by increasing the heating temperature and / or lengthening the heating time at the time of hot pressing on the innermost surface of the cylindrical member in Step 2. In order to increase the thickness of these skin layers, adjustment may be performed by increasing the heating temperature and / or increasing the heating time.

  The thin layer 430 may be created by increasing the heating temperature of the hot press of step 1 and / or increasing the heating time; or by increasing the amount of binder resin in step 3; Two types of glass wool sheets having different heat press conditions in step 1 (that is, one of the glass wool sheets has a higher density) may be overlaid and wound in step 2 while being overlaid. Even if the glass wool sheet and a high-density sheet made of another material (material that can be fixed such as adhesion to glass) are overlapped, the step 2 is wound in the overlapped state. Yes; these methods may be combined arbitrarily.

[Third Embodiment]
FIG. 4 is a schematic cross-sectional view of resin piping in the heat insulating piping system of the third embodiment. As elements other than the resin piping which comprises the heat insulation piping system of 3rd Embodiment, the element in said 1st Embodiment and 2nd Embodiment can be combined without being specifically limited.

[Resin piping 200b]
This embodiment is particularly useful when the resin pipe 200b shown in FIG. 4 is a pipe through which both cold water and hot water flow. In the resin pipe 200b, the first layer 210b, the second layer 220b, and the third layer 230b are laminated in this order in the direction from the axis O to the outer periphery. Between each layer, an adhesive layer or the like may or may not be interposed. In the resin pipe 200b, one or more other layers may be further laminated.

[First layer 210b, third layer 230b]
The 1st layer 210b and the 3rd layer 230b do not contain a fiber like the below-mentioned 2nd layer 220b. The inner layer 210b coats the inner peripheral surface of the second layer 220b so that fibers contained in the second layer 220b do not enter the fluid flowing through the resin pipe 200b. The third layer 230b prevents surface roughening so that the fibers contained in the second layer 220b are not exposed on the outer peripheral surface of the resin pipe 200b. As a result, the outer peripheral surface of the resin pipe 200b becomes smooth, so that the skin layer 410 (see FIG. 2 of the first embodiment and FIG. 3 of the second embodiment) of the heat-insulating fiber layer 400 and the outer peripheral surface of the resin pipe 200b. The contact becomes good, the air in contact with the outer peripheral surface of the resin pipe 200b is reduced, and the occurrence of condensation can be suppressed.

  The thickness of the first layer 210b and the third layer 230b may be 0.5 mm or more. Thereby, good surface smoothness and impact resistance performance can be obtained. The upper limit value within the thickness range of the first layer and the third layer is not particularly limited, but is 10 mm, for example, considering compatibility with dimensional stability.

  Both the first layer 210b and the third layer 230b are made of a thermoplastic resin. Thereby, the mechanical characteristics are uniform on both surfaces of the second layer 220b, and the manufacturing efficiency of the resin pipe 200b is good. The thermoplastic resin constituting the first layer 210b and the third layer 230b may be a polyolefin resin. As polyolefin resin, what was illustrated above as resin which comprises the resin piping 200 of 1st Embodiment can be used without specifically limiting. The thermoplastic resin constituting the first layer 210b and the thermoplastic resin constituting the third layer 230b may be the same or different.

[Second layer 220b]
The second layer 220b is made of a fiber reinforced resin including fibers in a thermoplastic resin that is a matrix resin. Resin piping inherently has a larger coefficient of linear expansion than metal piping, so thermal expansion and contraction due to the flow of cold / hot water in the piping is large, but the second layer 220b is a resin containing fibers, so resin piping. The thermal expansion and contraction of 200b is suppressed, and excellent dimensional stability is obtained. Therefore, even when cold / hot water flows into the resin pipe 200b, a gap or distortion at the joint S (see FIG. 1) of the heat insulating fiber layer 400 can be preferably prevented. For this reason, the stable heat insulation effect can be acquired in a wide temperature range.

(Material of second layer 220b-matrix resin)
The matrix resin in the second layer 220b is a thermoplastic resin, preferably a polyolefin resin. As the polyolefin-based resin, a resin similar to the resin constituting the first layer 210b and the third layer 230b may be used. More preferably, the matrix resin of the second layer 220b is the same as the resin constituting the first layer 210b and the third layer 230b. As a result, the adjacent layers are easily compatible with each other, and interface peeling can be effectively suppressed.

(Material of second layer 220b-fiber)
The material of the fiber contained in the second layer 220b includes inorganic fibers such as glass fiber, carbon fiber, ceramic fiber, and boron fiber; metal fiber; and aramid, polyester, polyethylene, polyamide, vinylon, polyacetal, polyparaphenylene benzoxazole And organic fibers such as high-strength polypropylene. Examples of the carbon fiber include PAN (polyacrylonitrile) -based carbon fiber, silicon-titanium-carbon fiber, and pitch-based carbon fiber. Examples of the organic fiber include natural fibers such as kenaf and hemp. In the present invention, the fibers are preferably glass fibers from the viewpoint of low linear expansion (low thermal stretchability). Said fiber can be used individually or in combination of multiple types.
Moreover, as a method for retaining the matrix resin in such a fiber, all known methods can be adopted.

  The fibers included in the second layer 220b may be surface-treated. For example, when the fiber is glass fiber, examples of the surface treatment agent include methacryl silane, acrylic silane, amino silane, imidazole silane, vinyl silane, and epoxy silane. Of these, aminosilane is preferred.

  As an aspect in which these fibers are arranged, an aspect in which continuous fibers are arranged in the longitudinal direction, an aspect in which continuous fibers arranged in the longitudinal direction, and continuous fibers intersecting with the continuous fibers are arranged, and a finite length is provided. The aspect by which the fiber of this is arranged is mentioned.

  The fiber length of the fibers included in the second layer 220b is shorter than the fiber length of the fibers constituting the heat insulating fiber layers 400 and 400a (see FIG. 2 of the first embodiment and FIG. 3 of the second embodiment). Thereby, the moldability is good and the orientation of the fibers can be easily controlled. Preferably, the fiber length of the fibers included in the second layer 220b is 5 mm or less. By setting the fiber length of the fiber within this range, the strength, rigidity, dimensional stability and elongation at high temperature of the molded body are effectively increased. From the viewpoint of more effectively increasing the strength, rigidity, dimensional stability and elongation at high temperature of the molded body, the fiber length of the fiber is preferably 3 mm or less, preferably 1 mm or less. Although the lower limit contained in the said fiber length range is not specifically limited, From a viewpoint of intensity | strength and rigidity, it may be 0.05 mm, for example, Preferably it may be 0.1 mm. The fiber length is an average length of fibers included in the second layer 220b.

  The fiber diameter of the fiber contained in the 2nd layer 220b is larger than the fiber diameter of the fiber which comprises the heat insulation fiber layers 400 and 400a (refer FIG. 2 of 1st Embodiment, and FIG. 3 of 2nd Embodiment). Thereby, preferable strength and rigidity can be provided. Preferably, the fiber diameter of the fibers included in the second layer 220b may be 5 μm or more and 50 μm or less, more preferably 12 μm or more and 50 μm or less. By setting the fiber diameter within this range, the strength, rigidity, dimensional stability, and elongation at high temperature of the molded body are effectively increased. From the viewpoint of further effectively increasing the strength, rigidity, dimensional stability, and elongation at high temperature of the molded body, the fiber diameter of the fiber is preferably 10 μm or more and 20 μm or less, more preferably 12 μm or more and 14 μm or less. . The fiber diameter is the average of the maximum diameters of the cross sections of the fibers included in the second layer 220b.

  The amount of fibers contained in the second layer 220b is 10% by weight or more and less than 60% by weight, based on 100% by weight of the entire resin composition for producing the second layer 220b. By setting the amount of the fiber to the above lower limit value or more, good dimensional stability of the resin pipe 200b can be obtained. By making the amount of fibers not more than the above upper limit value, good moldability can be obtained, and furthermore, the failure mode of the second layer 220b can be easily changed to ductile failure. Therefore, brittle fracture of the second layer 220b can be made difficult to occur.

(Second layer material-polyolefin sizing agent)
Furthermore, the fibers may be converged by a polyolefin sizing agent. The polyolefin sizing agent is not particularly limited as long as the glass fiber can be converged, but is specifically a polyolefin. The polyolefin may be the same as the matrix resin. That is, if the matrix resin is polyethylene, the sizing agent may also be polyethylene. Further, the polyolefin as the sizing agent includes a modified polyolefin. Specific examples of the polyolefin sizing agent include maleic acid-modified polyolefin and silane-modified polyolefin. From the viewpoint of providing the second layer 220b with a low linear expansion coefficient, the polyolefin sizing agent is preferably a silane-modified polyolefin, and the fibers are preferably glass fibers.

From the viewpoint of favorably converging the fibers, the density of the polyolefin sizing agent is preferably 0.85 g / cm ³ or more, and preferably 1.1 g / cm ³ or less.
From the viewpoint of favorably converging the fibers, the MFR (melt mass flow rate) of the polyolefin sizing agent is preferably 0.01 g / 10 min or more, and preferably 16 g / 10 min or less. The MFR is a value measured under conditions of a temperature of 190 ° C. and a load of 2.16 kgf based on JIS K7210.

  Any method may be used for converging the fibers with the polyolefin sizing agent. The amount of the fiber with respect to 100 parts by weight of the total of the matrix resin and the polyolefin sizing agent is preferably 6 parts by weight or more, more preferably 12 parts by weight or more, still more preferably 19 parts by weight or more, preferably 533 parts by weight or less. Is 171 parts by weight or less, more preferably 138 parts by weight or less. By setting the amount of fibers in the above range, the strength, dimensional stability and elongation at high temperature of the molded body are effectively increased.

(Second layer material-compatibilizer)
Further, the second layer 220b may include a compatibilizer. Examples of the compatibilizer include modified polyolefin and chlorinated polyolefin. Examples of the modified polyolefin include maleic acid-modified polyolefin and silane-modified polyolefin. One type of compatibilizer may be used alone, or two or more types may be used in combination. From the viewpoint of providing the second layer 220b with a low linear expansion coefficient, the compatibilizing agent is preferably a silane-modified polyolefin, and the fibers are preferably glass fibers.

  The modified polyolefin as the compatibilizer is distinguished from the modified polyolefin as the sizing agent. The amount of the compatibilizing agent contained in the second layer 220b is 0.5 wt% or more and 20 wt% or less, preferably 1 wt% or more, based on 100 wt% of the entire resin composition for producing the second layer 220b. 10% by weight or less. By setting the content of the compatibilizer in such a range, the strength, dimensional stability, and elongation at high temperature of the molded body are effectively increased. From the viewpoint of further effectively increasing the strength, dimensional stability and high temperature elongation of the molded body, the amount of the compatibilizing agent contained in the second layer 220b is preferably 2 wt% or more and 10 wt% or less. Preferably they are 2 weight% or more and 9 weight% or less.

[Layer thickness ratio]
The ratio of each layer of the resin pipe 200b is such that when the relative thickness of the first layer 210b is 1, the thickness of the second layer 220b is 2 or more and 6 or less, preferably 3 or more and 5 or less, and the relative thickness of the third layer 230b is 0. It is preferably 5 or more and 2 or less. By setting the thickness of each layer to such a ratio, it is possible to obtain good surface smoothness by the first layer 210b and the third layer 230b and good dimensional stability by the second layer 220b.

[Manufacturing]
The resin pipe 200b prepares a resin composition for manufacturing the first layer 210b and the third layer 230b and a resin composition for manufacturing the second layer 220b, respectively, and molds it using a molding machine. It does not specifically limit as a molding machine, A single screw extruder, a biaxial different direction parallel extruder, a biaxial different direction conical extruder, a biaxial same direction extruder, etc. are mentioned. Furthermore, when forming using a molding machine, the shaping mold, the resin temperature, and the like are not particularly limited.

[Modification of Third Embodiment]
Hereinafter, modified examples in which the aspect of the boundary of each layer of the resin piping is different will be described. In these modified examples, differences from the third embodiment are basically described, and descriptions of similar points are omitted.

[First Modification]
FIG. 5 is a schematic cross-sectional view of a first modified example of the resin piping in the heat insulating piping system of the third embodiment, and corresponds to FIG. 4 of the third embodiment. FIG. 6 is a partially enlarged view of FIG.

  The resin pipe 200c shown in FIG. 5 is laminated so that the first layer 210c, the second layer 220c, and the third layer 230c contact each other in this order in the direction from the axis O to the outer periphery. In the present modification, the resin pipe 200c includes three layers, but the present invention does not exclude that the resin pipe 200c further includes one or more other layers.

(Interface roughness)
In the resin pipe 200c, the interface 225c between the second layer 220c and the third layer 230c is roughened. Specifically, the ten-point average roughness Rz (based on JIS B 0601) of the interface 225c is 30 μm or more, preferably 50 μm or more. Furthermore, the interface maximum height Ry (based on JIS B 0601) of the interface 225c is 50 μm or more, preferably 100 μm or more. Thus, even when the resin pipe 200c is subjected to at least one of deformation due to an external force load and deformation due to environmental changes such as temperature change, humidity change, and aging deterioration, the second layer 220c and the third layer It is difficult to cause interface peeling with 230c.

The upper limit of the ten-point average roughness Rz of the interface 225c is, for example, 300 μm, preferably 200 μm. The upper limit of the interface maximum height Ry of the interface 225c is, for example, 500 μm, preferably 300 μm. Thereby, it is easy to ensure the ease of manufacture.
In FIG. 6, an average surface 225V is a surface serving as a reference for the ten-point average roughness Rz and the interface maximum height Ry.

(Linear expansion performance)
The resin pipe 200c is configured such that the linear expansion coefficient of the second layer 220c is smaller than the linear expansion coefficients of the first layer 210c and the third layer 230c. Specifically, the linear expansion coefficient of the second layer 220c may be 0.8 times or less, or 0.3 times or less of the linear expansion coefficient of the first layer 210c and the third layer 230c. More specifically, if the linear expansion coefficients of the first layer 210c and the third layer 230c are, for example, 12 × 10 ⁻⁵ or more and 14 × 10 ⁻⁵ or less, the linear expansion coefficient of the second layer 220c is 10 × 10 ^−. It may be around ⁵ (9.6 × 10 ⁻⁵ or more and 11.2 × 10 ⁻⁵ or less).

  The linear expansion coefficient of the resin pipe 200c can be obtained by the following method. The tube molded body is cut to an arbitrary length and cured for 2 hours or longer (for example, 24 hours) in a thermostatic bath set to an arbitrary temperature (Thot). After curing, the length of the tube molded body is measured (Lhot). Thereafter, the same tube molded body is cured for 2 hours or longer (for example, 24 hours) in a thermostatic bath set to an arbitrary temperature (Tcool) lower than that of Hot, and the length of the tube molded body is measured (Lcool). The obtained value is substituted into Equation 1 below to determine the linear expansion coefficient.

  Since the interface 225c of the resin pipe 200c is sufficiently rough, even if the linear expansion coefficient of the second layer 220c is 0.8 times or less that of the first layer 210c and the third layer 230c, Since the first layer 210c and the third layer 230c having a larger linear expansion coefficient preferably follow the two layers 220c, it is possible to obtain excellent peelability. The lower limit value included in the range of the linear expansion coefficient is not particularly limited, but is, for example, 0.01 times from the viewpoint of obtaining good peelability.

(Hot internal pressure creep performance)
Resin piping 200c suppresses brittle fracture in a hot internal pressure creep test at 80 ° C., so that no knee point (change point from ductile fracture to brittle fracture) occurs or the generation of knee points shifts to the longer side. It is preferable to suppress brittle fracture and more preferably no knee point is generated.

The resin pipe 200c has high creep performance at high temperatures, and has a wide application range as a pipe through which high-temperature fluid flows. The hot internal pressure creep test at 80 ° C. is tested at 80 ° C. using a hot internal pressure creep tester. An example of the hot internal pressure creep tester is a tester manufactured by Condo Science.
Specifically, regarding the internal pressure creep performance at 80 ° C. of the multi-resin pipe 200c, the circumferential stress is 5.0 MPa for 1000 hours or more, more preferably 5.1 MPa for 1000 hours or more, and further preferably 5. It is 1000 hours or more at 2 MPa. The time in the hot internal pressure creep performance is the fracture time. It is preferable that the multilayer pipe material has a high creep performance at high temperatures. When the creep performance at a high temperature of the multilayer pipe material is high, the applicable range is widened as a pipe through which a high-temperature fluid flows. Thus, the resin pipe 200c has long-term durability.

  The resin pipe 200c is particularly useful as a pipe through which cold water and hot water flow, in order to achieve both the above-described linear expansion performance and hot internal pressure creep performance.

(Layer thickness ratio)
As in the third embodiment, when the relative thickness T1c of the first layer 210c (see FIG. 6) is 1, the ratio of the respective layers of the resin pipe 200c is 2 or more and 6 or less, preferably Is preferably 3 or more and 5 or less, and the relative thickness T3c of the third layer 230c is preferably 0.5 or more and 2 or less. By setting the thickness of each layer to such a ratio, it is possible to obtain good surface smoothness by the first layer 210c and the third layer 230c, and good dimensional stability by the second layer 220c. The outer peripheral surface serving as a reference for the relative thickness T2c of the second layer 220c and the surface on the axis O side serving as the reference for the relative thickness T3c of the third layer 230c are the average surface 225V.

  The resin pipe 200c prepares a resin composition for manufacturing the first layer 210c and the third layer 230c and a resin composition for manufacturing the second layer 220c, and molds them using a molding machine. It does not specifically limit as a molding machine, A single screw extruder, a biaxial different direction parallel extruder, a biaxial different direction conical extruder, a biaxial same direction extruder, etc. are mentioned. Furthermore, when forming using a molding machine, the shaping mold, the resin temperature, and the like are not particularly limited.

  It is preferable that the extrusion rate of the resin composition layer constituting the second layer 220c is different from the extrusion rate of the resin composition layer constituting the third layer 230c. Thereby, the interface 225c can be preferably roughened. In this case, it is difficult to cause distortion or the like in the resin pipe 200c by lowering the extrusion speed of the resin composition layer constituting the third layer 230c than the extrusion speed of the resin composition layer constituting the second layer 220c. It is more preferable because of its affinity for mass production.

[Second Modification]
Drawing 7 is a typical sectional view of the 2nd modification of resin piping in a heat insulation piping system of a 3rd embodiment.
The resin pipe 200d shown in FIG. 7 is laminated so that the first layer 210d, the second layer 220d, and the third layer 230c are in contact with each other in order from the axis O to the outer periphery. In the resin pipe 200d, not only the interface 225c between the second layer 220d and the third layer 230c, but also the interface 215d between the first layer 210d and the second layer 220d is roughened similarly to the interface 225c. The specific interface roughness of the interface 215d is the same as that of the interface 225c.

  In the production of the resin pipe 200d, the extrusion speed of the resin composition layer constituting the first layer 210d is different from the extrusion speed of the resin composition layer constituting the second layer 220d, and the second layer 220d is constituted. It is preferable to make the extrusion speed of the resin composition layer to be made different from the extrusion speed of the resin composition layer constituting the third layer 230c. Thereby, the interface 215d and the interface 225c can be preferably roughened. In this case, the extrusion speed of the resin composition layer constituting the second layer 220d is slower than the extrusion speed of the resin composition layer constituting the first layer 210d, and the resin composition layer constituting the second layer 220d It is more preferable to slow down the extrusion rate of the resin composition layer constituting the third layer 230c than the extrusion rate from the viewpoint that the resin pipe 200d is less likely to be distorted and is more compatible with mass production.

  In addition to the first and second modifications described above, the present invention includes the first layer among the interface between the first layer and the second layer and the interface between the second layer and the third layer. A mode in which the interface between the first layer and the second layer is roughened is also included.

[Example 1]
The heat insulation piping system which combined the heat insulation piping system 100 shown in FIG. 2 and the resin piping 200b shown in FIG. 4 was created. That is, the heat insulation piping system with which the resin piping 200b was coat | covered with the heat insulation fiber layer 400 and the coating layer 510 was created.

The resin pipe 200b is made of polyethylene (density 0.948 g / cm ³ , MFR 0.05 g / 10 min) for producing the first layer 210b and the third layer 230b, and polyethylene (density 0) for producing the second layer 220b. .948 g / cm ³ , MFR 0.05 g / 10 min) as a matrix resin, 20% by weight of glass fiber (fiber length 3 mm, fiber diameter 13 μm) and 3% by weight of compatibilizer (silane-modified polyethylene) And was molded by coextrusion. Each of the three layers was extruded using separate single extruders. A single extruder of 40 mm was used for the first and third layers and a 75 mm single extruder was used for the second layer. The extrusion temperature was 200 ° C., and a dedicated three-layer mold was used as the mold. The obtained resin pipe 200b had an inner diameter of 51 mm and an outer diameter of 63 mm.

The linear expansion coefficient of the resin piping was determined as follows. The resin piping was cut to a length of 1000 mm and cured for 24 hours in a thermostatic bath set at 60 ° C. (Thot). After curing, the length (Lhot) of the multilayer pipe was measured. Thereafter, the same multilayer pipe was cured for 24 hours in a thermostatic bath set at 5 ° C. (Tcool), and the length (Lcool) of the multilayer pipe was measured. The obtained value was substituted into the following formula 1 to determine the linear expansion coefficient. As a result, the linear expansion coefficient of the resin pipe 200b was 5 × 10 ⁻⁵ / ° C.

The glass wool which is the heat insulation fiber layer 400 was coat | covered the outer surface of the resin piping 200b in 23 degreeC (normal temperature) environment. The average density of the glass wool was 45 kg / m ³ , and the skin layer 410 was 66 kg / m ³ (average density within a thickness range of 5 mm from the innermost circumference of the glass wool). The surface of the glass wool was wound and coated (thickness: 60 μm) with a low density polyethylene film as the coating layer 510.

(Test 1)
Using the heat insulating piping system created as described above, cold water (5 ° C.) and hot water (50 ° C.) were alternately flowed 100 cycles at intervals of 10 minutes inside the resin piping 200b. During this time, it was confirmed that no deviation occurred in the glass wool.

(Test 2)
Using the heat insulating piping system prepared as described above, the resin piping 200b was exposed to an environment of 30 ° C. and 80% humidity for 3 days while flowing cold water (5 ° C.). The weight before flowing cold water and the weight after exposing to the above environment for 3 days by flowing cold water were measured. If the weight difference between the two is within 1 g, it can be determined that there is no substantial change in weight, that is, good heat insulation. In this example, the increase was only 0.2 g, and good heat insulating properties were confirmed.

[Comparative Example 1]
A heat insulating piping system was created in the same manner as in Example 1 except that the skin layer 410 was not provided. When Test 2 of Example 1 was performed, dew condensation on the surface of the resin pipe 200b was confirmed.

  Preferred embodiments of the present invention are as described above, but the present invention is not limited to them, and various other embodiments are possible without departing from the spirit of the present invention.

[Correspondence between each part in embodiment and each component of claim]
The heat insulation piping systems 100 and 100a in this specification correspond to the “heat insulation piping system” in the claims, the resin pipings 200, 200b, 200c, and 200d correspond to “resin piping”, and the first layers 210b, 210c, and 210d The second layer 220b, 220c, 220d corresponds to the “second layer”, the third layer 230b, 230c corresponds to the “third layer”, and the heat insulating fiber layers 400, 400a correspond to the “first layer”. The skin layer 410 corresponds to the “skin layer”, the thin layer 430 corresponds to the “annular thin layer”, and the covering layer 510 corresponds to the “covering layer”.

100, 100a Thermal insulation piping system 200, 200b, 200c, 200d Resin piping 210b, 210c, 210d First layer 220b, 220c, 220d Second layer 230b, 230c Third layer 400, 400a Thermal insulation fiber layer 410 Skin layer 430 Thin layer ( Annular thin layer)
510 coating layer

Claims (12)

A resin pipe, a heat insulating fiber layer covering the outer peripheral surface of the resin pipe, and a coating layer covering the outer peripheral surface of the heat insulating fiber layer,
The heat insulating piping system, wherein the heat insulating fiber layer includes a skin layer on a surface of the resin piping. The average density of the heat-insulating fiber layer is not more than 20 kg / ^{m 3} or more 100 kg / ^{m 3,} heat insulation pipe system according to claim 1.   The heat insulation piping system according to claim 2, wherein the heat insulation fiber layer includes a plurality of thin tubular layers having a density higher than the average density in a substantially concentric manner. The resin pipe is a multilayer pipe including a first layer, a second layer, and a third layer in a direction from the axial center to the outer periphery;
The heat insulation piping system according to any one of claims 1 to 3, wherein the first layer is a thermoplastic resin, the second layer is a thermoplastic resin containing fibers, and the third layer is a thermoplastic resin.   The heat insulation piping system according to claim 4, wherein the fiber diameter of the fibers contained in the second layer is larger than the fiber diameter of the fibers constituting the heat insulation fiber layer. The fiber diameter of the fibers constituting the heat insulating fiber layer is 5 μm or more and 10 μm or less,
The heat insulation piping system of Claim 5 whose fiber diameter of the said fiber contained in a said 2nd layer is 12 micrometers or more and 50 micrometers or less.   The heat insulation piping system according to any one of claims 4 to 6, wherein a fiber length of the fibers contained in the second layer is smaller than a fiber length of fibers constituting the heat insulation fiber layer.   The heat insulation piping system according to claim 7, wherein a fiber length of the fibers constituting the heat insulation fiber layer is more than 5 mm, and a fiber length of the fibers contained in the second layer is 5 mm or less.   The relative thickness of the second layer is 2 or more and 6 or less, and the relative thickness of the third layer is 0.5 or more and 2 or less, where the relative thickness of the first layer is 1. 9 The heat insulation piping system of any one of these.   The content of the fiber in the second layer is 10% by weight or more and 60% by weight or less when the entire resin composition for producing the second layer is 100% by weight. The heat insulation piping system of any one of these.   The ten-point average roughness Rz of at least one of the interface between the first layer and the second layer and the interface between the second layer and the third layer is 30 μm or more. The heat insulation piping system of Claim 1.   The heat insulation piping system according to any one of claims 1 to 3, wherein the resin piping is made of a polyolefin resin, and the coating layer is made of a polyolefin resin.

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