Flexible tube

Abstract

To provide a flexible tube that is prevented from coming off from a nipple connected thereto, and easily recovers from blockage of the tube even if the tube is temporarily blocked.SOLUTION: A flexible tube 1 is provided by extruding a resin material into a cylindrical shape. An inner surface of the flexible tube 1 has at least one first region A1 and at least one second region A2, each extending in a longitudinal direction of the tube. The first regions A1 and the second regions A2 are provided alternately in a circumferential direction of the tube, a first resin material 11 is exposed in the first region, and a second resin material 12 is exposed in the second region. The first resin material 11 exposed in the first region A1 forms a circumferentially continuous tube so as to cover a radially outer side of the second resin material 12 exposed in the second region A2. The second resin material 12 is a resin material with higher tackiness than the first resin material 11.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a flexible tube.

Background Art

[0002] Flexible tubes formed by extrusion molding of resin materials such as rubber and elastomers are flexible and are used in a variety of applications, for example, in piping for scientific instruments, medical devices, and beverage / food handling equipment.

[0003] When using a flexible tube for the piping of these devices, the flexible tube is often connected to these devices by pushing the nipple of the device into the tube. For example, Patent Document 1 discloses a connection structure technique in which a protector having a bellows-shaped portion is provided outside a resin tube, and a portion where the resin tube is inserted into a nipple is covered with the protector. According to this technique, it is disclosed that the entire resin tube is protected by the protector and the reliability of the tube is improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, if the material of the flexible tube is slippery, it is likely to come out of the nipple, so the reliability of the piping decreases. That is, it is expected that the flexible tube is difficult to come out of the connected nipple.

[0006] On the other hand, when flexible tubing is bent with a small bending radius or subjected to negative pressure, the flexible tubing may kink or collapse, resulting in blockage. Flexible tubing is expected to prevent such blockages before they occur, and even if the tubing does become temporarily blocked, it is expected that the conduit will quickly recover and recover from the blockage once the bending or negative pressure is removed.

[0007] However, it has been difficult to make flexible tubes both difficult to pull out and to recover from blockage. If the tackiness of the inner peripheral surface of the flexible tube is increased in an attempt to make the tube difficult to pull out, when the tube becomes blocked, the tackiness causes the inner peripheral surface of the tube to stick to the blocked state, making it difficult to peel off, and making it difficult for the tube to recover its cylindrical shape.

[0008] An object of the present invention is to provide a flexible tube that is difficult to come off from a connected nipple and that is easy to recover from the tube blockage even if the tube is temporarily blocked. [Means for solving the problem]

[0009] As a result of extensive research, the inventors discovered that the above-mentioned problems could be solved by arranging a highly tacky resin material in a specific pattern on the inner surface of the tube, and thus completed the present invention.

[0010] The present invention is a flexible tube formed by extruding a resin material into a cylindrical shape, wherein the inner surface of the flexible tube has at least one first region and at least one second region, each extending in the longitudinal direction of the tube, the first region and the second region being arranged alternately in the circumferential direction of the tube, a first resin material being exposed in the first region and a second resin material being exposed in the second region, the first resin material exposed in the first region forming a circumferentially continuous tube so as to cover the radially outside of the second resin material exposed in the second region, and the second resin material being a resin material with higher tackiness than the first resin material (first invention).

[0011] In the first invention, preferably, when the tube is crushed so as to be blocked, at least a part of the first regions come into contact with each other on the inner peripheral surfaces facing each other (second invention). Further, in the first invention, preferably, when the tube is crushed so as to be blocked, the second regions do not come into contact with each other on the inner peripheral surfaces facing each other (third invention).

Advantages of the Invention

[0012] According to the flexible hose of the present invention (first invention), it is difficult to come off from the connected nipple, and even if the tube is temporarily blocked, the effect that it is easy to recover from the blockage of the tube can be obtained.

[0013] Further, in the second invention or the third invention, the effect that it is easier to recover from the blockage of the tube can also be obtained.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments of the invention will be described by taking, as an example, a flexible hose connected as a pipe to a physicochemical instrument such as an analyzer with reference to the drawings. The invention is not limited to the individual embodiments shown below, and it can also be implemented by changing the form.

[0016] As shown in Fig. 1, the flexible tube 1 of the first embodiment is a flexible tube obtained by extruding a resin material into a cylindrical shape. Fig. 2 shows a cross section of the flexible tube 1 of the first embodiment. Note that hatching in the cross section has been omitted in Figs. 1 to 5 to make the drawings easier to see. Here, the cylindrical shape may be a cylindrical shape, an elliptical cylindrical shape, or a rectangular cylindrical shape.

[0017] The extrusion-molded flexible tube has a substantially uniform cross section along the length of the tube. The cross section of the tube may vary along the length of the tube. Furthermore, as the tube advances along its length, the direction of the cross section of the tube may be constant, and the tube may have a linear feature along the length, or the cross section of the tube may rotate in a predetermined direction, and the tube may have a gentle spiral feature (for example, a spiral pitch of 10 times or more the diameter of the tube). In this embodiment, the flexible tube 1 is formed by extruding a resin material into a cylindrical shape, and the characteristic feature in the cross section of the tube is linearly arranged along the center line of the tube.

[0018] The inner circumferential surface of the flexible tube 1 has at least one first region A1, A1 and at least one second region A2, A2, each extending in the longitudinal direction of the tube. In FIG. 2, these regions are indicated by arrows representing sections. Although not required, in this embodiment, the first region A1, A1 and the second region A2, A2 are each provided in a straight line parallel to the central axis of the tube. Note that a third region may be provided on the inner circumferential surface of the flexible tube 1 between the first region A1 and the second region A2.

[0019] The first regions A1, A1 and the second regions A2, A2 are alternately provided in the circumferential direction of the tube 1. Although not essential, in this embodiment, four first regions A1, A1 and four second regions A2, A2 are provided. Although not essential, in this embodiment, the first regions A1, A1 are provided so as to be wider in the circumferential direction of the tube than the second regions A2, A2.

[0020] The resin material constituting the flexible tube 1 is not particularly limited, and rubber, thermoplastic elastomer, etc. can be used as long as they do not prevent the flexibility of the tube. In the flexible tube 1 of the present embodiment, at least two types of resin materials are used.

[0021] In the flexible tube 1, on the inner peripheral surface of the tube, the first resin material 11 is exposed in the first regions A1, A1, and the second resin material 12 is exposed in the second regions A2, A2. And the first resin material 11 exposed in the first regions A1, A1 forms a tube continuous in the circumferential direction so as to cover the radially outer side of the portion formed of the second resin material 12 exposed in the second regions A2, A2.

[0022] In other words, the flexible tube 1 of the present embodiment has a substantially linear strip formed of the second resin material 12 integrated on the inner peripheral surface of the tube formed of the first resin material 11, and on the inner peripheral surface of the tube, the first resin material 11 and the second resin material 12 are alternately exposed in a substantially linear manner. Although not essential, if necessary, an outer layer that serves as a coating layer, a protective layer, a reinforcing layer, a blocking layer, etc. may be provided on the outer peripheral side of the flexible tube 1 of the present embodiment, or members such as reinforcing threads may be added.

[0023] In the inner periphery of the hose, the portion formed of the first resin material 11 and the portion formed of the second resin material 12 are integrated so as not to come apart. The means of integration is not particularly limited, and the first resin material 11 and the second resin material 12 may be joined by means such as welding, adhesion, and bonding to each other. Alternatively, the two may be integrated by making the portion formed of the first resin material 11 and the portion formed of the second resin material 12 have a shape that mechanically engages with each other.

[0024] The second resin material 12 is a resin material having higher tackiness than the first resin material 11. Here, tackiness is an index indicating the adhesiveness of the surface of the resin material, and is an index measured by the following method. A test specimen is made by molding the resin material into a sheet and placing it horizontally. A jig (mass 130 g, contact area 35 cm2) made of polyamide resin (e.g., MC nylon) whose surface comes into contact with the material is placed on the resin sheet, and the value at the moment the jig begins to move when the jig is pulled horizontally with a force gauge is taken as the measurement value of tackiness.

[0025] Although not essential, the preferred range of tackiness of the first resin material 11 is 0.6 to 0.8 N, and the preferred range of tackiness of the second resin material 12 is 1.1 to 1.3 N. Although not essential, the difference in tackiness between the second resin material 12 and the first resin material 11 is preferably 0.2 to 0.9 N, more preferably 0.6 to 0.8 N.

[0026] There are no particular limitations on the resin materials that can be used as the first resin material 11 and the second resin material 12, but examples include soft resins such as soft vinyl chloride resins, and thermoplastic elastomers such as olefin-based thermoplastic elastomers and styrene-based thermoplastic elastomers (for example, LEASTOMER (registered trademark) from Riken Technos Corporation). The tackiness of these resin materials can be adjusted by adding a tackifier or adjusting the hardness.

[0027] For example, in the flexible hose 1 of this embodiment, a styrene-based thermoplastic elastomer (Tefabloc, manufactured by Mitsubishi Chemical Corporation) is used as the first resin material 11, and its tackiness is 0.7 N. An olefin-based thermoplastic elastomer (Tafmer, manufactured by Mitsui Chemicals, Inc.) is used as the second resin material 12, and its tackiness is 1.2 N.

[0028] Although not necessary, in the flexible tube 1, preferably, when the tube is crushed so as to be blocked, at least a part of the first regions A1, A1 on the inner peripheral surfaces facing each other come into contact with each other. The state where the flexible tube 1 is crushed is shown in FIGS. 3 and 4. In this case, in any of the figures, the first resin materials 11 are in contact with each other. If the width of the first regions A1, A1 is made larger than the width of the second regions A2, A2, such a contact form of the inner surface can be realized.

[0029] Also, although not necessary, in the flexible tube 1, preferably, as in the contact form shown in FIG. 4, when the tube is crushed so as to be blocked, on the inner peripheral surfaces facing each other, the second regions A2, A2 do not come into contact with each other. In this case, in FIG. 4, the second resin material 12 does not contact the second resin material 12 on the opposing inner peripheral surface, and contacts the first resin material 11 on the opposing inner peripheral surface. A part of the tube wall of the flexible tube 1 may be formed thinly so as to be crushed in such a form, the tube may be formed in an elliptical cylinder shape, or the tube may be given a kink.

[0030] The flexible tube 1 of the first embodiment can be manufactured by extruding the first resin material 11 and the second resin material 12 in a tubular shape so as to have a cross section as shown in FIG. 2 by so-called two-color extrusion molding. The extruded resin material is subjected to a cross-linking treatment or a cooling treatment according to the properties of the resin, and its shape is fixed in a hollow tube shape.

[0031] The operation and effect of the flexible tube 1 of the first embodiment will be described. According to the flexible tube 1 of the first embodiment, the effect that it is difficult to come off from the connected nipple and that even if the tube is temporarily blocked, it is easy to recover from the blockage of the tube can be obtained.

[0032] That is, since the second resin material 12 with relatively high tackiness is exposed on the second regions A2, A2 of the inner peripheral surface of the flexible tube 1, when a nipple or the like of a device to be connected is inserted, the second resin material 12 with high tackiness comes into contact with the nipple, increasing the frictional force and making it difficult for the tube to come out of the nipple.

[0033] Also, in a conventional flexible tube, if the inner peripheral surface of the tube is made of a resin material with high tackiness such as the second resin material 12, when the tube is crushed and blocked, the second resin materials 12 on the inner peripheral surface of the tube come into contact with each other and stick together, and there is a problem that the blockage of the tube is difficult to recover even when the tube is unloaded.

[0034] On the other hand, in the flexible tube 1 of the first embodiment, the first regions A1, A1 and the second regions A2, A2 are alternately provided in the circumferential direction of the tube. In the first regions A1, A1, the first resin material 11 is exposed, and in the second regions A2, A2, the second resin material 12 is exposed. Therefore, when the tube is blocked due to kinking, negative pressure, etc., on the inner peripheral surface of the flexible tube 1, there are portions where the first resin material 11 and the second resin material 12 come into contact with each other, or portions where the first resin materials 11 come into contact with each other. Since the first resin material 11 has relatively lower tackiness than the second resin material 12, at these portions, the inner peripheral surfaces of the tube are likely to separate from each other.

[0035] Therefore, when the bending or negative pressure of the tube is released, the inner peripheral surfaces of the tube are likely to separate at these portions. Starting from these portions, the entire inner peripheral surface of the tube separates and returns to a cylindrical shape, making it easier for the tube to recover from the blockage.

[0036] Further, although not essential, when the flexible tube 1 is configured such that at least a part of the first regions 11A1, A1 contact each other on the inner peripheral surfaces facing each other when the tube is crushed so as to be blocked, the tube is particularly likely to recover from the blockage. At the portion where a part of the first regions A1, A1 where the first resin 11 with low tackiness is exposed contact each other, the adhesion between the first resins 11 with low tackiness is weak, and starting from this portion, the inner peripheral surface of the adhered tube is likely to peel off.

[0037] Further, although not essential, when the flexible tube 1 is configured such that the second regions A2, A2 do not contact each other on the inner peripheral surfaces facing each other when the tube is crushed so as to be blocked, the tube is particularly likely to recover from the blockage. If the second regions A2, A2 where the second resin 12 with high tackiness is exposed contact each other, the adhesion at that portion becomes strong and is likely to hinder the recovery of the tube from the blockage. However, if there is no such portion, the tube is more likely to recover from the blockage.

[0038] A flexible tube of the first embodiment having an outer diameter of 6 mm, an inner diameter of 4 mm, and a ratio (W1 / W2) of the width (W1: 2.7 mm) of the first regions A1, A1 to the width (W2: 0.5 mm) of the second regions A2, A2 of 5.4 was manufactured as Example 1. On the other hand, a tube having an outer diameter of 6 mm and an inner diameter of 4 mm made of only the first resin material 11 was manufactured as Comparative Example 1. Further, a tube having an outer diameter of 6 mm and an inner diameter of 4 mm was manufactured using the second resin material 12 for the entire tube as Comparative Example 2.

[0039] The flexible tubes of the above examples and comparative examples were inserted into a tube nipple, and the resistance when pulling and removing the tube was evaluated. In Comparative Example 1, when the tube was pulled, it was easily torn and could be pulled out (the pulling force was about 35 N), but the flexible tube of the example could not be pulled out without applying a considerable force (it could not be pulled out even with 50 N). The tube of Comparative Example 2 also could not be pulled out without applying a considerable force (it could not be pulled out even with 50 N).

[0040] Next, a test was carried out to recover the flexible tubes of the above-mentioned Examples and Comparative Examples from kinks. Each sample was cut to a length of approximately 130 mm, bent 180 degrees so that the center of the sample was kinked and crushed (blocked), fixed with tape, and left in that state for 16 hours.The tape was then removed, the load was removed, and the sample was left for 5 minutes to evaluate whether the tube's restoring force would recover from the kinks and blockages.

[0041] In Comparative Example 1, the blocked state of the tube was released, and the bent portion of the tube itself returned to nearly its original state. The blocked state of the flexible tube of the Examples was also released, and the bent portion of the tube itself returned to nearly its original state. On the other hand, in the tube of Comparative Example 2, the bent angle remained at about 45 degrees, and the kinked portion did not fully recover, so the blocked state of the tube was not released.

[0042] As described above, the flexible tube of the embodiment is difficult to come off from the nipple to which it is connected, and even if the tube is temporarily blocked, it is easy to recover from the blockage.

[0043] The invention is not limited to the above-described embodiment, and various modifications can be made to the invention. Other embodiments of the invention will be described below, focusing on differences from the above-described embodiment, and detailed descriptions of similarities will be omitted. Furthermore, these embodiments can be implemented by combining parts of them with each other or by substituting parts of them.

[0044] The pattern in which the first regions A1, A1 and the second regions A2, A2 are arranged on the inner circumferential surface of the flexible tube may be, for example, as follows. 5 shows a cross section of the flexible tube 2 of the second embodiment. In the flexible tube 2, three second regions A2, A2 in which the second resin material 12 is exposed are arranged on the inner periphery of the tube. These second regions A2, A2 may be arranged at equal intervals.

[0045] When an odd number of second regions A2, A2 where the second resin material 12 is exposed, such as the flexible tube 2, are arranged, when the tube is crushed and blocked, on the inner peripheral surfaces facing each other, the second regions do not come into contact with each other, and in particular, it becomes easy to recover from the blockage of the tube.

[0046] In addition, in the description of the above embodiment, examples were shown in which each of the first regions A1, A1 was provided with the same width, or each of the second regions A2, A2 was provided with the same width. However, each of the first regions A1, A1 and each of the second regions A2, A2 may have different widths. In addition, in the description of the above embodiment, examples were shown in which the first regions A1, A1 and the second regions A2, A2 were provided to be rotationally symmetric at a predetermined angle around the center of the tube, or provided in a symmetric shape with the diameter of the tube as the axis. However, the first regions A1, A1 and the second regions A2, A2 may be provided asymmetrically in the rotational direction, or may be provided asymmetrically with the diameter as the axis.

Industrial Applicability

[0047] The above flexible tube can be used, for example, in the piping of an analytical device, and has high industrial utility value.

Explanation of Reference Numerals

[0048] 1 Flexible tube 11 First resin material 12 Second resin material A1 First region A2 Second region 2 Flexible tube

Claims

Claim 1 A flexible tube formed by extruding a resin material into a tubular shape, wherein the inner peripheral surface of the flexible tube has at least one first region and at least one second region extending in the longitudinal direction of the tube, the first region and the second region are alternately provided in the circumferential direction of the tube, in the first region, a first resin material is exposed, in the second region, a second resin material is exposed, the first resin material exposed in the first region forms a circumferentially continuous tube so as to cover the radially outer side of the second resin material exposed in the second region, the second resin material is a resin material having higher tackiness than the first resin material, A flexible tube. Claim 2 When the tube is crushed so as to be blocked, at least a part of the first regions come into contact with each other on the inner peripheral surfaces facing each other, The flexible tube according to claim 1. Claim 3 When the tube is crushed so as to be blocked, the second regions do not come into contact with each other on the inner peripheral surfaces facing each other, The flexible tube according to claim 1.

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