Tube, method for manufacturing the same, and manufacturing apparatus

Abstract

This tube has an even thickness and the load thereon is not concentrated on one point during use. The tube is highly durable, and the discharge performance thereof is stable even when the tube is used for a peristaltic pump or the like. The tube has a long shape constant in the longitudinal direction and has: a flow passage 12 penetrating the inside of the tube in the longitudinal direction; and a resin part 13 surrounding the flow passage 12. The resin part 13 is formed from a laminated body in which multiple expanded polytetrafluoroethylene layers 16 laminated in the radial direction of the flow passage 12 and elastomer layers 18 bonding the polytetrafluoroethylene layers 16 are alternatively laminated. The elastomer layer 18 is formed from at least one kind of elastomer, and a gap of the polytetrafluoroethylene layers 16 is impregnated with part of the elastomer. The average value of the thicknesses of the resin part 13 in at least four directions intersecting one another in the radial direction of the flow passage 12, the thickness ratio calculated from thicknesses in directions opposing each other among the thicknesses in the four directions, and the lamination number of the polytetrafluoroethylene layers 16 and the elastomer layers 18 satisfy predetermined conditions.

Description

Technical Field

[0001] The present invention relates to a flexible tube used in a peristaltic pump for transporting fluids, a method for manufacturing the same, and a manufacturing apparatus.

Background Art

[0002] Conventionally, peristaltic pumps have been used in applications such as the feeding and metering transfer of fluids in the fields of biomedicine, pharmaceuticals, and chemistry, and flexible tubes are used in peristaltic pumps. Such tubes are required to have mechanical resistance to repeated bending operations, and various forms of them have been manufactured.

[0003] For example, the bend-resistant composite elastomer structure disclosed in Patent Document 1 is a composite material having a plurality of stretched and expanded polytetrafluoroethylene layers. The polytetrafluoroethylene layers are impregnated with a liquid elastomer and cured, and the impregnated polytetrafluoroethylene layers are adhered to each other through an elastomer layer. The manufacturing method of this composite elastomer structure is to thinly impregnate and apply a liquid elastomer to a film made of stretched and expanded polytetrafluoroethylene, and wind it around a shaft until it reaches a predetermined thickness. After curing the wound product, the tube can be obtained by extracting the shaft. By winding, alternately layered polytetrafluoroethylene layers and elastomer layers are formed, and the progress of cracks can be prevented. This structure has an effect of preventing holes and leakage against tearing and breakage caused by repeated bending operations, and improves durability.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventional tubes, if their wall thickness is not uniform, or if they contain wrinkles or air bubbles between the overlapping stretched polytetrafluoroethylene layers, will experience reduced durability due to torsional forces and localized force concentration when repeatedly occluded by the rollers of a peristaltic pump. Furthermore, insufficient adhesive strength will result in areas between the stretched polytetrafluoroethylene layers. This creates locally weak points within the tube, leading to delamination or rupture and shortening the lifespan. If there are thin sections, these sections receive less load when occluded by the pump, while the load concentrates on the thicker sections. Additionally, the force dissipating to the thin sections can cause torsional forces on the tube, potentially leading to rupture before achieving its intended durability. Moreover, uneven wall thickness due to thin sections hinders reliable and stable repeated occlusion of the tube's flow path, resulting in unstable discharge volume during pumping.

[0006] In the background technology described above, while there are restrictions on the thickness of each layer of the stretched polytetrafluoroethylene layer and elastomer, there are no restrictions on the thickness variation when a tube is formed from multiple layers, resulting in challenges in durability against repeated occlusion. Furthermore, if the number of turns (layers) of the stretched polytetrafluoroethylene layer is excessive relative to the wall thickness, the tube becomes rigid and loses its resilience. However, in the background technology described above, the number of turns is set at 31 or more layers, and measures to prevent excessive layering have not been considered.

[0007] Furthermore, in the manufacturing process described in the background technology above, a film made of stretched polytetrafluoroethylene is passed through the gap between two rollers to introduce liquid elastomer onto the film. However, there is a risk that the liquid elastomer introduced may become thinner due to roller slippage. Also, passing the film through the gap between the two rollers causes the film to stretch and change thickness, affecting the thickness when laminated. Uneven thickness can also occur if the elastomer is not introduced into the stretched polytetrafluoroethylene layer at a uniform thickness, and no measures have been taken to prevent this.

[0008] This invention has been made in view of the problems of the background art described above, and aims to provide a tube with uniform wall thickness, where load is not concentrated in specific areas during use, has high durability, and provides stable discharge even when used in peristaltic pumps, as well as a method for manufacturing the same and a manufacturing apparatus for the same. [Means for solving the problem]

[0009] The present invention relates to a tube that is a long object with a constant shape in the longitudinal direction, comprising a channel that penetrates the inside in the longitudinal direction and a resin portion surrounding the channel, wherein the resin portion is configured as a laminate in which a plurality of stretchable polytetrafluoroethylene layers stacked in the radial direction of the channel and elastomer layers that bond the layers of the polytetrafluoroethylene layers are alternately stacked, the elastomer layers consist of at least one type of elastomer, the polytetrafluoroethylene layers have voids, and a portion of the elastomer is impregnated into the voids, and the average value of the wall thickness of the resin portion in four mutually orthogonal directions in the radial direction of the channel at one cross section at an arbitrary position in the longitudinal direction of the tube, the wall thickness ratio which is the average value of the ratio of the wall thicknesses of opposing sides in the four directions, and the number of layers of the polytetrafluoroethylene layer and the elastomer layer satisfy the following conditions. When the average wall thickness is 0.5 mm or more and less than 2.8 mm, the wall thickness ratio is 1.0 to 1.2, and when the average wall thickness is 2.8 mm or more and less than 10.3 mm, the wall thickness ratio is 1.0 to 1.1. Furthermore, regarding the number of layers, if the average thickness is 0.5 mm or more and less than 1.4 mm, the number of layers is 5 or more and less than 35; if the average thickness is 1.4 mm or more and less than 2.0 mm, the number of layers is 14 or more and less than 50; if the average thickness is 2.0 mm or more and less than 2.8 mm, the number of layers is 20 or more and less than 70; if the average thickness is 2.8 mm or more and less than 4.0 mm, the number of layers is 28 or more and less than 100; if the average thickness is 4.0 mm or more and less than 6.2 mm, the number of layers is 40 or more and less than 155; if the average thickness is 6.2 mm or more and less than 7.7 mm, the number of layers is 62 or more and less than 193; and if the average thickness is 7.7 mm or more and less than 10.3 mm, the number of layers is 77 or more and less than 258. Within the average range of the aforementioned wall thicknesses, if the number of layers is excessively increased beyond the specified range, the adhesive strength between the elastomers becomes insufficient, causing the stretch-expanded polytetrafluoroethylene layer and the elastomer layer to easily peel off, impairing durability. Furthermore, tubes manufactured with fewer layers than the specified range result in an uneven thickness due to the elastomer layer being too thick, failing to meet the wall thickness ratio requirements.

[0010] The elastomer is silicone, urethane, nitrile rubber, styrene-butadiene rubber, chloroprene, phosphazene, perfluoropolyether elastomer, methyl silicone, phenyl silicone, fluoroelastomer, perfluoroelastomer, or a combination thereof. The inner surface of the flow channel of the tube is smooth, with an arithmetic mean roughness Ra of 0.01 to 0.80 and / or a 10-point mean roughness Rz of 0.01 to 3.00. In particular, it is used as a tube installed in a peristaltic pump, which is repeatedly occluded by the rollers of the peristaltic pump.

[0011] Furthermore, the present invention involves drawing a polytetrafluoroethylene film from a roll of stretched and expanded polytetrafluoroethylene, impregnating the polytetrafluoroethylene film with a liquid elastomer, and winding the polytetrafluoroethylene film impregnated with the liquid elastomer onto a winding shaft. windingThe method for manufacturing a tube involves heat treatment to promote the crosslinking reaction of the liquid elastomer, thereby bonding the layers of the polytetrafluoroethylene film, and forming a laminate in which layers of polytetrafluoroethylene made of the polytetrafluoroethylene film and elastomer layers made of the liquid elastomer are alternately stacked. The coating process involves supplying the liquid elastomer to the upper surface of the polytetrafluoroethylene film, pressing a first blade vertically from above the surface of the polytetrafluoroethylene film to make contact with the upper surface of the polytetrafluoroethylene film, scraping off the excess liquid elastomer to create a uniform thickness, and then pressing a second blade, which is inclined so that its lower end in contact with the polytetrafluoroethylene film is facing downstream, to make contact with the upper surface of the polytetrafluoroethylene film from above to scrape off the excess again to create a uniform thickness, thereby coating the liquid elastomer with a uniform thickness using the first and second blades, and simultaneously impregnating the polytetrafluoroethylene film with the liquid elastomer. The tube is a long object with a constant shape in the longitudinal direction, has a channel that penetrates through it in the longitudinal direction on its inside, and has a resin portion surrounding the channel, The resin portion comprises a plurality of polytetrafluoroethylene layers stacked in the radial direction of the flow channel, and an elastomer layer that bonds the layers of the polytetrafluoroethylene layers. In the radial cross-section of the flow path The layers are wound in a spiral shape and stacked alternately, the elastomer layer consists of at least one type of elastomer, the polytetrafluoroethylene layer has voids, and a portion of the elastomer is impregnated into the voids. In one cross-section at any position in the longitudinal direction of the tube, the average value of the wall thickness of the resin portion in four mutually orthogonal directions in the radial direction of the flow path is calculated, and the wall thickness ratio, which is the average value of the ratio of the wall thicknesses of opposing sides in the four directions, and the number of layers of the polytetrafluoroethylene layer and the elastomer layer are determined. When the average wall thickness is 0.5 mm or more and less than 2.8 mm, the wall thickness ratio is 1.0 to 1.2, and when the average wall thickness is 2.8 mm or more and less than 10.3 mm, the wall thickness ratio is 1.0 to 1.1. Furthermore, the method for manufacturing tubes is such that, regarding the number of layers, when the average wall thickness is 0.5 mm or more and less than 1.4 mm, the number of layers is 5 or more and less than 35; when the average wall thickness is 1.4 mm or more and less than 2.0 mm, the number of layers is 14 or more and less than 50; when the average wall thickness is 2.0 mm or more and less than 2.8 mm, the number of layers is 20 or more and less than 70; when the average wall thickness is 2.8 mm or more and less than 4.0 mm, the number of layers is 28 or more and less than 100; when the average wall thickness is 4.0 mm or more and less than 6.2 mm, the number of layers is 40 or more and less than 155; when the average wall thickness is 6.2 mm or more and less than 7.7 mm, the number of layers is 62 or more and less than 193; and when the average wall thickness is 7.7 mm or more and less than 10.3 mm, the number of layers is 77 or more and less than 258.

[0012] Furthermore, the present invention provides a plurality of film support rollers for guiding the polytetrafluoroethylene film drawn from a roll of polytetrafluoroethylene film made of stretched and expanded polytetrafluoroethylene, The polytetrafluoroethylene film that was pulled out Wind it up Winding shaft and An apparatus for a coating process, provided between the raw material and the winding shaft, for applying and impregnating the polytetrafluoroethylene film with a liquid elastomer, A heat treatment apparatus is provided for heat-treating the polytetrafluoroethylene film that has been coated and impregnated with the liquid elastomer wound on the winding shaft, thereby promoting the crosslinking reaction of the liquid elastomer and bonding the layers of the polytetrafluoroethylene film. The device for manufacturing tubes is configured as a laminate in which layers of polytetrafluoroethylene made of the polytetrafluoroethylene film and elastomer layers made of the liquid elastomer are alternately stacked. The apparatus for the coating process includes a liquid elastomer supply device that supplies and places the liquid elastomer onto the upper surface of the polytetrafluoroethylene film flowing from the raw material toward the winding shaft, and a first blade provided for scraping the liquid elastomer to a uniform thickness, the first blade being pressed almost vertically from above the polytetrafluoroethylene film surface onto the upper surface of the polytetrafluoroethylene film, and a second blade provided downstream of the first blade for further scraping the liquid elastomer to a more uniform thickness, the second blade being pressed from above the polytetrafluoroethylene film surface onto the upper surface of the polytetrafluoroethylene film, and the second blade being inclined such that its lower end in contact with the polytetrafluoroethylene film faces downstream. The tube manufactured by the manufacturing apparatus is a long object with a constant shape in the longitudinal direction, and comprises a flow path that penetrates the inside in the longitudinal direction and a resin portion that surrounds the flow path. The resin portion comprises a plurality of polytetrafluoroethylene layers stacked in the radial direction of the flow channel, and an elastomer layer that bonds the layers of the polytetrafluoroethylene layers. In the radial cross-section of the flow path The layers are spirally wound and alternately stacked, the elastomer layer consists of at least one type of elastomer, the polytetrafluoroethylene layer has voids, and a portion of the elastomer is impregnated into these voids. In one cross-section at any position in the longitudinal direction of the tube, the average value of the wall thickness of the resin portion in four mutually orthogonal directions in the radial direction of the flow path is calculated, and the wall thickness ratio, which is the average value of the ratio of the wall thicknesses of opposing sides in the four directions, and the number of layers of the polytetrafluoroethylene layer and the elastomer layer are determined. When the average wall thickness is 0.5 mm or more and less than 2.8 mm, the wall thickness ratio is 1.0 to 1.2, and when the average wall thickness is 2.8 mm or more and less than 10.3 mm, the wall thickness ratio is 1.0 to 1.1. Furthermore, the tube manufacturing apparatus produces tubes with the following values ​​for the number of layers: when the average wall thickness is 0.5 mm or more and less than 1.4 mm, the number of layers is 5 or more and less than 35; when the average wall thickness is 1.4 mm or more and less than 2.0 mm, the number of layers is 14 or more and less than 50; when the average wall thickness is 2.0 mm or more and less than 2.8 mm, the number of layers is 20 or more and less than 70; when the average wall thickness is 2.8 mm or more and less than 4.0 mm, the number of layers is 28 or more and less than 100; when the average wall thickness is 4.0 mm or more and less than 6.2 mm, the number of layers is 40 or more and less than 155; when the average wall thickness is 6.2 mm or more and less than 7.7 mm, the number of layers is 62 or more and less than 193; and when the average wall thickness is 7.7 mm or more and less than 10.3 mm, the number of layers is 77 or more and less than 258.

[0013] The first blade is provided between a pair of film support rollers, with the upstream film support roller being lower than the other downstream film support roller, and the lower end of the first blade being lower than the downstream film support roller but at the same height as the upstream film support roller, and the polytetrafluoroethylene film flows substantially horizontally between the upstream film support roller and the first blade. A second blade is provided downstream of the film support roller located downstream of the first blade, and a winding shaft is provided downstream of the second blade, the lower end of the second blade is lower than the upper end of the film support roller located downstream of the first blade, and pushes the polytetrafluoroethylene film downward, the winding shaft is located below the lower end of the second blade, and the second blade and The aforementioned This is a tube manufacturing apparatus in which the polytetrafluoroethylene film flows diagonally downward towards the downstream direction between the winding shafts. [Effects of the Invention]

[0014] The tube of the present invention, the method for manufacturing the same, and the tube manufactured by the manufacturing apparatus have a constant wall thickness, have no variation due to deformation sites, have no partial concentration of load during use, and have high durability. As a result, when the tube of the present invention is used in a positive displacement pump or the like, the discharge of the fluid is stabilized. Further, since the surface roughness of the inner surface of the tube of the present invention is small and smooth, when the tube is crushed to block the internal space, the friction when the inner wall of the tube adheres is reduced, and fine detachment of the innermost surface can be prevented. Thereby, the mixing of foreign matters into the discharged fluid can be suppressed.

Brief Description of Drawings

[0015] [Figure 1] It is a cross-sectional view of a tube according to an embodiment of this invention. [Figure 2] It is a schematic view of the manufacturing process of the tube of this embodiment.

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of this invention will be described based on the drawings. FIG. 1 shows an embodiment of this invention. The tube 10 of this embodiment is an elongated object having a constant shape in the longitudinal direction, and includes a flow path 12 having a circular cross-section that penetrates the inside in the longitudinal direction, and a cylindrical resin portion 13 that surrounds the periphery of the flow path 12. FIG. 1 shows a cross-sectional structure substantially perpendicular to the longitudinal direction of the tube 10.

[0017] The resin portion 13 is configured as a laminate in which a plurality of polytetrafluoroethylene layers 16 laminated in the radial direction of the flow path 12 and an elastomer layer 18 that adheres between the polytetrafluoroethylene layers 16 are alternately laminated. The polytetrafluoroethylene layer 16 is wound around the periphery of the flow path 12 a plurality of layer times to form a cylindrical body The cross-section of the polytetrafluoroethylene layer 16 is formed in a spiral shape in the radial plane around the channel 12. and is formed. The polytetrafluoroethylene layer 16 has a large number of fine voids, and a part of the material of the elastomer layer 18 is impregnated in the voids.

[0018] Here, the polytetrafluoroethylene layer 16 is described. The polytetrafluoroethylene layer 16 consists of a polytetrafluoroethylene film 17 made of stretched and expanded polytetrafluoroethylene, which is prepared using a reactive lubricant. The reactive lubricant consists of uncured silicone and a solvent such as kerosene, naphtha, or mineral spirits of the choice. The polytetrafluoroethylene film 17 is manufactured by lubricating, extruding, and stretching and expanding fine powder of polytetrafluoroethylene. During the stretching and expanding process, the silicone cures in situ, forming an interwoven polymer network structure (IPN) of polytetrafluoroethylene and silicone elastomer. Such a stretched and expanded polytetrafluoroethylene film 17 has residual pores, high strength, and moderate resilience. Here, the polytetrafluoroethylene film 17 has, for example, a thickness of 30 μm and a pore size of 0.1 μm.

[0019] Next, the elastomer layer 18 will be described. The elastomer layer 18 consists of at least one type of elastomer, which is, for example, liquid silicone during the coating process, has a hardness of 60 on durometer A, a viscosity of 25 Pa·s, a tensile strength of 7.3 MPa, and an elongation of 180%. In addition to silicone, a fluororesin may also be used. Fluorine-based resins have excellent chemical resistance and possess sufficient flexibility even in the presence of aggressive chemical substances (acids, alkalis, solvents such as toluene and MEK). If the viscosity of the elastomer to be coated is high and it does not impregnate the voids of the polytetrafluoroethylene layer 16 during the coating process, it is diluted with a solvent before use.

[0020] The inner surface of the channel 12 is formed to be smooth. The smoothness of the inner surface of the channel 12 satisfies at least one of the following conditions: arithmetic mean roughness Ra is 0.01 to 0.80, and 10-point mean roughness Rz is 0.01 to 3.00.

[0021] The tube 10 satisfies the conditions shown in Table 1 below, regarding the wall thickness t and wall thickness ratio of the resin portion 13, and the number of layers I of the polytetrafluoroethylene layer 16 and elastomer layer 18. Satisfying these conditions results in good durability. The wall thickness t of the resin portion 13 is the average value of the wall thicknesses ta, tb, tc, and td of the resin portion 13 in at least four intersecting directions A, B, C, D, i.e., in the radial direction of the flow path 12, for example, in at least four mutually orthogonal directions A, B, C, D, from the center 0 shown in Figure 1, in a cross-section of the tube 10 on a plane approximately perpendicular to the longitudinal direction of the tube 10. The wall thickness ratio is the average value of the ratio of the wall thicknesses of opposing sides in the four directions. In this embodiment, the tube 10 is manufactured with the optimal wall thickness ratio and the number of layers I set to satisfy the optimal conditions for obtaining high durability, corresponding to the value of the wall thickness t. The optimal conditions for wall thickness t, wall thickness ratio, and number of layers I are shown in Table 1 below. [Table 1]

[0022] Here, regarding the wall thickness t, wall thickness ratio, and number of layers I, the values ​​for the wall thickness ratio in Table 1 are rounded to two decimal places, taking into account the allowable error. As a result, the following conditions are obtained for the optimal wall thickness, wall thickness ratio, and number of layers I that have high durability. When the average value of the wall thickness t is 0.5 mm or more and less than 2.8 mm, the wall thickness ratio is 1.0 to 1.2, and when the average value of the wall thickness t is 2.8 mm or more and less than 10.3 mm, the wall thickness ratio is 1.0 to 1.1. The number of layers I is as shown in Table 1.

[0023] Next, the manufacturing method for the tube 10 of this embodiment will be described with reference to Figure 2. This manufacturing method produces a tube 10 in which the conditions of wall thickness t, wall thickness ratio, and number of layers I are within the optimal range for high durability performance, as shown in Table 1 above.

[0024] First, the polytetrafluoroethylene film 17, which will become the polytetrafluoroethylene layer 16, is pulled out from the raw roll 20 of polytetrafluoroethylene film 17 guided by multiple film support rollers 22, and sent to the coating process 24 in which liquid elastomer 19, which will form the elastomer layer 18, is applied. In the coating process 24, the polytetrafluoroethylene film 17, which has been thinly coated with liquid elastomer 19, is sent to the winding shaft 26 wind it up .

[0025] The winding shaft 26 has a circular cross-sectional shape corresponding to the shape of the flow path 12. The winding shaft 26 is coated with fluororesin to facilitate peeling. Furthermore, since the surface condition of the shaft 26 is transferred to the inner surface of the tube, a tube with a smooth inner surface can be obtained by finishing the surface of the shaft 26 as smoothly as possible or by covering it with a heat-shrinkable fluororesin tube. The preferred range for the surface roughness of the inner circumferential surface of the flow path 12 of the tube 10 is that it satisfies at least one of the following conditions: arithmetic mean roughness Ra is 0.01 to 0.80 and ten-point mean roughness Rz is 0.01 to 0.3.

[0026] The material wound on the winding shaft 26 is heat-treated to promote the crosslinking reaction of the liquid elastomer 19, bonding the layers of the polytetrafluoroethylene film 17 together, and is constructed as a laminate in which polytetrafluoroethylene layers 16 and elastomer layers 18 are alternately stacked. The heat treatment is performed, for example, by heating in an oven. After that, the winding shaft 26 is withdrawn, the channel 12 is formed, and the tube 10 is completed.

[0027] The coating process 24, in which the liquid elastomer 19 is applied, is performed near the film support roller 22a, directly in front of the winding shaft 26. First, the apparatus for the coating process 24 will be described.

[0028] Upstream of the film support roller 22a, a first blade 28 is provided between it and the next film support roller 22b located upstream, for scraping the liquid elastomer 19 to a uniform thickness. The first blade 28 is pressed against the upper surface of the polytetrafluoroethylene film 17 from above, almost vertically. The lower end 28a of the first blade 28 pressed against the upper surface of the polytetrafluoroethylene film 17 is lower than the film support roller 22a, pushing the polytetrafluoroethylene film 17 downwards from the film support roller 22a. The film support roller 22b, located upstream of the film support roller 22a, is lower than the film support roller 22a and at approximately the same height as the lower end 28a of the first blade 28. Between the film support roller 22b and the first blade 28, the polytetrafluoroethylene film 17 flows almost horizontally.

[0029] A liquid elastomer supply device (not shown) is provided between the first blade 28 and the film support roller 22b, and the liquid elastomer 19 is placed on the upper surface of the polytetrafluoroethylene film 17.

[0030] Downstream of the film support roller 22a, a second blade 30 is provided between it and the winding shaft 26 to further scrape the liquid elastomer 19 to make it a more uniform thickness. The second blade 30 is pressed against the upper surface of the polytetrafluoroethylene film 17 from above. The second blade 30 is inclined such that its lower end 30a, which is in contact with the polytetrafluoroethylene film 17, faces downstream. The lower end 30a of the second blade 30 is located slightly lower than the upper end of the film support roller 22a, pushing the polytetrafluoroethylene film 17 slightly below the upper end of the film support roller 22a. The winding shaft 26, located downstream of the second blade 30, is located slightly below the lower end 30a, and the polytetrafluoroethylene film 17 flows diagonally downward towards the downstream direction between the second blade 30 and the winding shaft 26.

[0031] Next, the coating process 24 will be described. Liquid elastomer 19 is supplied from a liquid elastomer supply device (not shown) and placed on the upper surface of the polytetrafluoroethylene film 17 flowing in contact with the film support roller 22b. The first blade 28 then scrapes off the excess to create a uniform thickness. The film then passes through the film support roller 22a and comes into contact with the second blade 30, where the excess is scraped off again to create a uniform thickness. The first blade 28 and the second blade 30 coat the liquid elastomer 19 with a uniform thickness and simultaneously ensure that the liquid elastomer 19 impregnates the micropores of the polytetrafluoroethylene film 17.

[0032] In this embodiment of the tube 10, the conditions for the wall thickness t of the resin part 13, the wall thickness ratio, and the number of layers I are such that the wall thickness ratio is kept small within a certain range to stabilize durability and improve durability. Furthermore, when the wall thickness t is 2.8 mm or more, the value of the wall thickness ratio is kept relatively small, which suppresses the absolute value of the variation in wall thickness, improving durability even for tubes 10 with relatively thick wall thickness t. Furthermore, by setting the number of layers I within the above-mentioned preferred range, even higher durability can be obtained. In other words, by setting the wall thickness of the tube 10 to be relatively uniform within a predetermined range under the above conditions, there is no variation depending on the part of the tube 10 when it deforms, and the load is not concentrated in certain parts, resulting in high durability. Therefore, when used in a peristaltic pump, the fluid discharge is stable. Furthermore, by making the wall thickness uniform within a predetermined range, it is possible to prevent variations in durability depending on the direction in which the tube 10 is installed in the peristaltic pump.

[0033] Furthermore, according to the tube 10 of this embodiment, the inner surface roughness is small and smooth, so when the tube is crushed to close the internal space, friction when the inner wall of the tube adheres is reduced, and minute detachment of the innermost surface can be prevented. This makes it possible to suppress the mixing of foreign matter into fluids such as discharged liquid. The tube 10 can be easily manufactured by coating a polytetrafluoroethylene film 17 with a liquid elastomer 19. In the coating step 24 of the liquid elastomer 19, the first blade 28 and the second blade 30 come into contact twice to scrape off excess liquid elastomer 19 and make it a uniform thickness, ensuring that it is reliably impregnated into the voids of the polytetrafluoroethylene film 17, and making it possible to manufacture a tube 10 that meets the optimal conditions for obtaining high durability.

[0034] Furthermore, the tube of this invention is not limited to the above embodiments, and the method for manufacturing the polytetrafluoroethylene film that forms the polytetrafluoroethylene layer may be other than those described above. The material of the elastomer layer may also be other than those described above. The number and position of film support rollers in the manufacturing process, the position in the coating process, etc., can be changed as appropriate. The longitudinal length of the tube is flexible, and the tube can be used for a variety of applications. [Explanation of Symbols]

[0035] 10 tubes 12 channels 13 Resin part 16 Polytetrafluoroethylene layer 17 Polytetrafluoroethylene film 18 Elastomer layer 19 Liquid elastomer

Claims

1. A tube that is a long object with a constant shape in the longitudinal direction, and has a flow channel that penetrates through the inside in the longitudinal direction, and a resin part that surrounds the flow channel, The resin portion is configured as a laminate in which a plurality of stretchable and expandable polytetrafluoroethylene layers stacked radially in the channel and elastomer layers that bond the layers of the polytetrafluoroethylene layers are alternately stacked, the elastomer layers consist of at least one type of elastomer, the polytetrafluoroethylene layers have voids, and a portion of the elastomer is impregnated into the voids. The elastomer of the elastomer layer is silicone, urethane, nitrile rubber, styrene-butadiene rubber, chloroprene, phosphazene, perfluoropolyether elastomer, methyl silicone, phenyl silicone, fluoroelastomer, perfluoroelastomer, or a combination thereof. The inner surface of the flow channel is smooth, with an arithmetic mean roughness Ra of 0.01 to 0.80 and / or a 10-point mean roughness Rz of 0.01 to 3.

00. In one cross-section at any position in the longitudinal direction of the tube, the average value of the wall thickness of the resin portion in four mutually orthogonal directions in the radial direction of the flow path is calculated, and the wall thickness ratio, which is the average value of the ratio of the wall thicknesses of opposing sides in the four directions, and the number of layers of the polytetrafluoroethylene layer and the elastomer layer are determined. When the average wall thickness is 0.5 mm or more and less than 2.8 mm, the wall thickness ratio is 1.0 to 1.2, and when the average wall thickness is 2.8 mm or more and less than 10.3 mm, the wall thickness ratio is 1.0 to 1.

1. Furthermore, regarding the number of layers, If the average thickness is 0.5 mm or more and less than 1.4 mm, the number of layers is 5 or more and less than 35. If the average thickness is 1.4 mm or more and less than 2.0 mm, the number of layers is 14 or more and less than 50. If the average value of the wall thickness is 2.0 mm or more and less than 2.8 mm, the number of layers is 20 or more and less than 70. If the average thickness is 2.8 mm or more and less than 4.0 mm, the number of layers is 28 or more and less than 100. If the average value of the wall thickness is 4.0 mm or more and less than 6.2 mm, the number of layers is 40 or more and less than 155. If the average value of the wall thickness is 6.2 mm or more and less than 7.7 mm, the number of layers is 62 or more and less than 193. A tube characterized in that, when the average wall thickness is 7.7 mm or more and less than 10.3 mm, the number of layers is 77 or more and less than 258.

2. The tube according to claim 1, wherein the tube is repeatedly blocked by the rollers of a peristaltic pump.

3. This is a method for manufacturing a tube in which polytetrafluoroethylene film made of stretched and expanded polytetrafluoroethylene is drawn from a raw roll of polytetrafluoroethylene film, liquid elastomer is applied to the polytetrafluoroethylene film and impregnated, the polytetrafluoroethylene film impregnated with liquid elastomer is wound onto a winding shaft, heat treatment is performed to promote the crosslinking reaction of the liquid elastomer and bond the layers of the polytetrafluoroethylene film, thereby forming a laminate in which polytetrafluoroethylene layers made of the polytetrafluoroethylene film and elastomer layers made of the liquid elastomer are alternately stacked. The coating process involves supplying the liquid elastomer to the upper surface of the polytetrafluoroethylene film, pressing a first blade vertically from above the surface of the polytetrafluoroethylene film to make contact with the upper surface of the polytetrafluoroethylene film, scraping off the excess liquid elastomer to create a uniform thickness, and then pressing a second blade, which is inclined so that its lower end in contact with the polytetrafluoroethylene film is facing downstream, to make contact with the upper surface of the polytetrafluoroethylene film from above to scrape off the excess again to create a uniform thickness, thereby coating the liquid elastomer with a uniform thickness using the first and second blades, and simultaneously impregnating the polytetrafluoroethylene film with the liquid elastomer. The tube is a long object with a constant shape in the longitudinal direction, has a channel that penetrates through it in the longitudinal direction on its inside, and has a resin portion surrounding the channel, The resin portion is arranged in such a way that a plurality of polytetrafluoroethylene layers stacked radially in the channel and elastomer layers bonding the polytetrafluoroethylene layers are alternately stacked in a spiral shape in the radial cross-section of the channel, the elastomer layers consist of at least one type of elastomer, the polytetrafluoroethylene layers have voids, and a portion of the elastomer is impregnated into the voids. In one cross-section at any position in the longitudinal direction of the tube, the average value of the wall thickness of the resin portion in four mutually orthogonal directions in the radial direction of the flow path is calculated, and the wall thickness ratio, which is the average value of the ratio of the wall thicknesses of opposing sides in the four directions, and the number of layers of the polytetrafluoroethylene layer and the elastomer layer are determined. When the average wall thickness is 0.5 mm or more and less than 2.8 mm, the wall thickness ratio is 1.0 to 1.2, and when the average wall thickness is 2.8 mm or more and less than 10.3 mm, the wall thickness ratio is 1.0 to 1.

1. Furthermore, regarding the number of layers, If the average thickness is 0.5 mm or more and less than 1.4 mm, the number of layers is 5 or more and less than 35. If the average thickness is 1.4 mm or more and less than 2.0 mm, the number of layers is 14 or more and less than 50. If the average value of the wall thickness is 2.0 mm or more and less than 2.8 mm, the number of layers is 20 or more and less than 70. If the average thickness is 2.8 mm or more and less than 4.0 mm, the number of layers is 28 or more and less than 100. If the average value of the wall thickness is 4.0 mm or more and less than 6.2 mm, the number of layers is 40 or more and less than 155. If the average value of the wall thickness is 6.2 mm or more and less than 7.7 mm, the number of layers is 62 or more and less than 193. A method for manufacturing a tube, characterized in that, when the average wall thickness is 7.7 mm or more and less than 10.3 mm, the number of layers is 77 or more and less than 258.

4. Multiple film support rollers for guiding the polytetrafluoroethylene film drawn from a roll of polytetrafluoroethylene film made of stretched and expanded polytetrafluoroethylene, A winding shaft for winding up the drawn-out polytetrafluoroethylene film, An apparatus for a coating process, provided between the raw material and the winding shaft, for applying and impregnating the polytetrafluoroethylene film with a liquid elastomer, A heat treatment apparatus is provided for heat-treating the polytetrafluoroethylene film that has been coated and impregnated with the liquid elastomer wound on the winding shaft, thereby promoting the crosslinking reaction of the liquid elastomer and bonding the layers of the polytetrafluoroethylene film. The device for manufacturing tubes is configured as a laminate in which layers of polytetrafluoroethylene made of the polytetrafluoroethylene film and elastomer layers made of the liquid elastomer are alternately stacked. The apparatus for the coating process includes a liquid elastomer supply device that supplies and places the liquid elastomer onto the upper surface of the polytetrafluoroethylene film flowing from the raw material toward the winding shaft, and a first blade provided for scraping the liquid elastomer to a uniform thickness, the first blade being pressed almost vertically from above the polytetrafluoroethylene film surface onto the upper surface of the polytetrafluoroethylene film, and a second blade provided downstream of the first blade for further scraping the liquid elastomer to a more uniform thickness, the second blade being pressed from above the polytetrafluoroethylene film surface onto the upper surface of the polytetrafluoroethylene film, and the second blade being inclined such that its lower end in contact with the polytetrafluoroethylene film faces downstream. The tube manufactured by the manufacturing apparatus is a long object with a constant shape in the longitudinal direction, and comprises a flow path that penetrates the inside in the longitudinal direction and a resin portion that surrounds the flow path. The resin portion is constructed by alternately stacking a plurality of polytetrafluoroethylene layers, which are stacked radially in the channel, and elastomer layers, which bond the layers of the polytetrafluoroethylene layers, in a spiral shape in the radial cross-section of the channel. The elastomer layers consist of at least one type of elastomer, and the polytetrafluoroethylene layers have voids, in which a portion of the elastomer is impregnated. In a cross-section at any position in the longitudinal direction of the tube, the average value of the wall thickness of the resin portion in four mutually orthogonal directions in the radial direction of the flow path is calculated, and the wall thickness ratio, which is the average value of the ratio of the wall thicknesses of opposing sides in the four directions, and the number of layers of the polytetrafluoroethylene layer and the elastomer layer are determined. When the average wall thickness is 0.5 mm or more and less than 2.8 mm, the wall thickness ratio is 1.0 to 1.2, and when the average wall thickness is 2.8 mm or more and less than 10.3 mm, the wall thickness ratio is 1.0 to 1.

1. Furthermore, regarding the number of layers, If the average thickness is 0.5 mm or more and less than 1.4 mm, the number of layers is 5 or more and less than 35. If the average thickness is 1.4 mm or more and less than 2.0 mm, the number of layers is 14 or more and less than 50. If the average value of the wall thickness is 2.0 mm or more and less than 2.8 mm, the number of layers is 20 or more and less than 70. If the average thickness is 2.8 mm or more and less than 4.0 mm, the number of layers is 28 or more and less than 100. If the average value of the wall thickness is 4.0 mm or more and less than 6.2 mm, the number of layers is 40 or more and less than 155. If the average value of the wall thickness is 6.2 mm or more and less than 7.7 mm, the number of layers is 62 or more and less than 193. A tube manufacturing apparatus characterized in that, when the average wall thickness is 7.7 mm or more and less than 10.3 mm, the number of layers is manufactured to a value of 77 or more and less than 258.

5. The first blade is provided between a pair of film support rollers, with the upstream film support roller being lower than the other downstream film support roller, and the lower end of the first blade being lower than the downstream film support roller but at the same height as the upstream film support roller, and the polytetrafluoroethylene film flows substantially horizontally between the upstream film support roller and the first blade. A tube manufacturing apparatus according to claim 4, wherein a second blade is provided downstream of the film support roller located downstream of the first blade, a winding shaft is provided downstream of the second blade, the lower end of the second blade is located lower than the upper end of the film support roller located downstream of the first blade, and the winding shaft is located below the lower end of the second blade, and the polytetrafluoroethylene film flows between the second blade and the winding shaft at an inclination downward toward the downstream direction.

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