JP2000018444A - Medium transferring hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medium transferring hose of high durability and production efficiency of the hose respectively by reducing yarn fatigue caused by repetitive bending or pressure, and spirally braiding the reinforcing yarns around the outer periphery of an inner tube. SOLUTION: A medium transferring hose is prepared by laminating sequentially a first reinforcing yarn layer, a second reinforcing yarn layer, and an outer rube on an outer peripheral surface of an inner tube. The first reinforcing yarn layer is composed of reinforcing yarn spirally wound around the outer periphery of the inner tube. The second reinforcing yarn layer is composed of reinforcing yarn spirally wound round the outer periphery of the first reinforcing yarn layer in the opposite direction to the winding direction of the first layer. The braid density of the reinforcing yans of the first and second layers is 70% or more. The first and second reinforcing yarns are twisted yarns, while their first twist and final twist numbers are both 8 times/10 cm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium transport hose for transporting various gases, liquids or gas-liquid mixed media.

[0002]

2. Description of the Related Art
Hose for transporting various gases, liquids, or gas-liquid mixed media must be able to withstand the pressure generated by the medium flowing inside the hose, and must be repeatedly used when connecting hoses to various equipment and when using media circulation. Since bending is added,
It is required to withstand repeated bending. For this reason, those in which an inner tube and an outer tube are formed of resin and rubber and a reinforcing layer is provided between both tubes are generally used. For example, ethylene-propylene-diene terpolymer (EPDM) and isobutylene-isoprene are used. Rubber (IIR) is used for the inner and outer tubes, and as a reinforcing layer, an organic fiber such as polyethylene terephthalate, nylon, rayon, and aramid fiber, or a metal fiber or metal wire such as a steel wire or a steel cord is wound around the outer periphery of the inner tube. Alternatively, those woven into a cloth in advance are used.

In recent years, among these fibers, aramid fibers have attracted attention due to their high strength properties.

[0004] There are two types of knitting structures when these reinforcing yarns are wound around the outer circumference of the inner tube, namely, a braided structure and a spiral structure. A spiral structure that can be wound in a short time and has high production efficiency is used. It is more preferably employed.

However, the yarn used for these reinforcing layers suffers from a fatigue fracture phenomenon due to repeated pressurization and bending, and eventually the yarn breaks, and the hose cannot withstand the pressure of the flowing medium, and the hose breaks. And the hose had to be replaced frequently. Such a phenomenon was particularly remarkable in high-strength fibers such as aramid fibers lacking in bending resistance.

Therefore, in order to prevent such yarn fatigue, attempts have been made to further increase the degree of fatigue by increasing the number of twists of the yarn by using a twisted structure. However, if the number of twists of the ply-twisted yarn is increased, the yarn width becomes smaller. Therefore, when this is wound spirally around the inner tube outer periphery, the gap between the yarns increases, and the inner tube is formed by the reinforcing yarn layer. There has been a problem that the suppressing effect is remarkably reduced, and the inner tube material blows through the yarn gap to break the hose.

[0007] Thus, the yarn fatigue of the reinforcing yarn layer is small,
Moreover, a hose having a reinforcing yarn layer formed by spiral structure knitting with good production efficiency and capable of remarkably reducing hose breakage has not yet been obtained.

The present invention has been made in view of the above circumstances, and reduces the fatigue of a reinforcing yarn due to repeated bending and pressure, and greatly reduces the breakage of a hose obtained by knitting a reinforcing yarn around the inner tube by a spiral structure. It is an object of the present invention to provide a medium transport hose excellent in durability that can be used for a long period of time even under severe medium distribution conditions.

[0009]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies to achieve the above object, and as a result, by setting the reinforcing yarn to a specific twist number region, the fatigue of the yarn is reduced. It has been found that by significantly reducing breakage and knitting them to a specific knitting density, it is possible to prevent the inner tubing material from blowing through the yarn gap and to prevent early breakage, As a means for realizing the invention, it was found that the reinforcing yarn layers were wound in a spiral structure in opposite directions to each other, so that it was possible to obtain a medium transporting hose having good durability without causing hose destruction with high production efficiency, which led to the present invention. Things.

That is, the present invention relates to a medium transport hose in which a first reinforcing yarn layer, a second reinforcing yarn layer, and an outer tube are sequentially laminated on the outer periphery of an inner tube. The second reinforcing yarn layer is constituted by a reinforcing yarn wound spirally around the outer periphery in a direction opposite to the first reinforcing layer around the outer periphery of the first reinforcing yarn layer. And the knitting density of the entire reinforcing yarn of the second reinforcing yarn layer is 70% or more, and the first and second reinforcing yarns are plied yarns, and both the number of times of twist and the number of times of twist are 8 times / Provided is a medium transport hose having a length of 10 cm or more.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to FIG. The hose of FIG. 1 includes an inner tube 1, a first reinforcing yarn layer 2, a second reinforcing yarn layer 3, and an outer tube 4.

Here, the material for forming the tube in the hose includes:
It is appropriately selected in consideration of deterioration resistance performance, permeation resistance, swelling resistance, mechanical strength, etc. with respect to the medium flowing inside the hose,
For example, ethylene / propylene / diene terpolymer (E
PDM), rubber such as isobutylene / isoprene rubber, acrylonitrile butadiene rubber, butyl rubber, chloroprene rubber, chlorinated butyl rubber, chlorosulfonated polyethylene, acrylic rubber, ethylene acrylic rubber, and resins such as polyethylene, polyvinyl chloride and polystyrene.
Thermoplastic elastomers and the like can be mentioned. In addition, general additives such as a filler, a processing aid, an antioxidant, a vulcanizing agent, and a vulcanization accelerator can be appropriately blended with these base materials.

The inner tube may have a single-layer structure or a multi-layer structure of two or more layers. The example of FIG. 1 has a two-layer structure including an inner layer 1a and an outer layer 1b. With such a structure having two or more layers, the inner layer 1a is formed of a material having excellent chemical resistance particularly according to the type of the medium, while the outer layer 1a is formed.
b can provide structural support.

The thickness of the inner tube 1 is not particularly limited, but is about 0.2 to 5 mm, especially about 0.5 to 3 mm. When the inner layer 1a is provided, the thickness is 0.01
About 0.8 mm.

Next, the first reinforcing yarn layer 2 is spirally wound around the outer circumference of the inner tube 1, and the second reinforcing yarn layer 3 is spirally wound in the opposite direction to the first reinforcing yarn layer 2. It is provided. In this case, the knitting density of the entire yarns constituting these two reinforcing yarn layers is 70% or more,
More preferably, it is 75 to 98%. Here, the knitting density indicates the occupation density of the yarn per unit area. If the knitting density is less than 70%, the gap between the yarns becomes too large, and it becomes impossible to prevent the inner tube material from blowing through the yarn gap. As described above, since the first reinforcing yarn layer 2 and the second reinforcing yarn layer 3 are both wound in a spiral shape, the work is easy and the production efficiency is high. And, since the first reinforcing yarn layer 2 and the second reinforcing yarn layer 3 are provided by being wound in a spiral shape in the opposite direction, the mechanical strength and the bending resistance of each reinforcing yarn layer are synergistically improved, and hose breakage occurs. In addition, the effect of suppressing the inner layer by the reinforcing yarn layer is improved.

The reinforcing yarn forming the first reinforcing yarn layer 2 and the second reinforcing yarn layer 3 is a yarn having a twist structure, and the number of twists is
The number of twists and the number of twists are both 8 times / 10 cm or more, preferably 9 to 30 times / 10 cm. If the number of primary twists or the number of primary twists is less than 8 turns / 10 cm, the yarn is liable to cause fatigue fracture due to repeated pressing and bending, which is not preferable. The yarn of the ply twist structure used in the present invention is not limited to the two-stage twist of the primary twist and the primary twist, but may be a three-stage twist consisting of a primary twist, an intermediate twist, and a primary twist, or a twisting process of four or more stages. And the number of intermediate twists in this case can be set as appropriate.

There may be a plurality of yarn layers between the first reinforcing yarn layer and the inner tube, or an intermediate material layer may be provided between the first reinforcing yarn layer and the second reinforcing yarn layer. Is also good.

The material of the reinforcing yarn forming the first reinforcing yarn layer 2 and the second reinforcing yarn layer 3 is an organic fiber such as nylon, polyester, rayon, and aramid fiber, various metal wires,
Metal fibers and metal wires such as metal cords can be used alone or in combination of two or more. Aramid fibers are preferable in terms of high elastic modulus and high strength. For example, they are represented by the following general formula (1). Para-aramid fiber or the like is preferably used.

[0019]

Embedded image

In the present invention, the first reinforcing yarn and the second reinforcing yarn can be used by twisting two or more kinds of fibers, and for example, may be twisted of aramid fiber and polyester fiber.

Here, as shown in FIG. 1, between the first reinforcing yarn layer and the second reinforcing yarn layer, various rubbers, resins, thermoplastic elastomers, or An intermediate layer 5 composed of a mixture thereof or the like can be provided. The thickness of the intermediate layer is 0.01 to 2.0.
mm, especially 0.1 to 1.0 mm.

The outer tube 4 is provided for protecting the first reinforcing yarn layer and the second reinforcing yarn layer and for improving the pressure resistance of the hose, and is made of the same resin, thermoplastic elastomer as the constituent material of the inner tube. , Rubber, or the like, and is formed by coating the outer periphery of the second reinforcing yarn layer by extrusion molding, tube coating, or the like. The outer tube may be formed in a plurality of layers according to the strength design and the environment in which the hose is used. Although the thickness of the outer tube is appropriately selected, it is usually 0.2 to 4.0 mm, especially 0.5 to 3.0 mm.
It is.

In the present invention, a separate reinforcing yarn layer and other known reinforcing yarn layers may be further provided between the second reinforcing yarn layer and the outer pipe, and the effect of the present invention is not impaired. An adhesive layer and other intermediate layers may be appropriately provided between the respective layers.

[0024]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 6] Manufacture of hose First, a mandrel having a diameter of 11 mm was coated with a mixed resin of 6 nylon and polyolefin to a thickness of 0.15 mm. Next, a rubber composition was prepared with the following composition, and this was extruded and coated on a mandrel to a thickness of 1.2 mm to form an inner tube. Formulation: Acrylonitrile butadiene rubber 100 parts by weight (trade name Zetpol 2020, manufactured by Zeon Corporation) FEF carbon 60 parts by weight Stearic acid 1 part by weight Plasticizer (trade name: Thiokol TP95, manufactured by Thiokol Chemical Company) 10 parts by weight Zinc white 5 parts by weight Agent M 1.5 parts by weight Accelerator TT 1 part by weight Sulfur 0.5 part by weight

Next, two 1500-denier low-twisted yarns were twisted to obtain a 3000-denier first reinforcing yarn. Here, the material of the yarn, the number of times of twisting and the number of times of twisting are as shown in Table 1. In Table 1, the blended reinforcing yarns were prepared by preparing a yarn of each material as a lower-twisted yarn of 1500 denier and twisting it. The obtained first reinforcing yarn was spirally wound around the outer periphery of the inner tube at a static angle of 54 ° 44 to form a first reinforcing yarn layer. 1 at this time
Table 1 shows the number of aligned yarns per pitch.

On the first reinforcing yarn layer, an intermediate layer is formed by extruding a rubber composition similar to that of the inner tube having the above-mentioned composition to a thickness of 0.3 mm, and a second reinforcing yarn is further provided thereon with the first reinforcing yarn. The second reinforcing yarn layer was wound in a spiral shape opposite to the yarn layer at a static angle of 54 ° 44. Here, as the second reinforcing yarn, a material having the same material as the first reinforcing yarn and the number of times of twisting and the number of times of twisting were used. Table 1 shows the overall knitting density of the first reinforcing yarn layer and the second reinforcing yarn layer.

The same outer layer of the second reinforcing yarn layer is extruded and coated with the same rubber composition as the inner tube having the above composition to a thickness of 1.2 mm.
After the whole was vulcanized and cured, the mandrel was pulled out to produce the medium transport hose of the present invention.

[Comparative Examples 1 to 4] For comparison, the same procedure as in the above example was performed except that the number of times of twisting, the number of times of twisting, and the knitting density of the first reinforcing yarn and the second reinforcing yarn were as shown in Table 1. To manufacture hoses. Hose Durability Evaluation In order to evaluate the durability of the hose, a repeated pressurization test was conducted at an oil temperature and an ambient temperature of 155 ° C. and an internal pressure of 36 kg / cm.
^{2. The} pressurization cycle was performed with a 60 CPM crisp wave (according to the standards of the Japan Refrigeration and Air Conditioning Industry Association). After 500,000 times, ○ indicates that there was no abnormality, and X indicates that there was abnormality such as burst or wetting. The results are also shown in Table 1.

[0030]

[Table 1]

As is evident from the results in Table 1, by setting the number of twists of the reinforcing yarn and the knitting density within the range of the present invention, there is no breakage of the yarn and no break-through breakage between the yarns.
A highly durable hose is obtained. On the other hand, as shown in the comparative examples, when the number of twists and the knitting density are out of the range of the present invention, it is found that breakage of the yarn or blow-through breakage between the yarns occurs.

[0032]

According to the medium transporting hose of the present invention, the fatigue of the reinforcing yarn due to repeated bending and pressure is reduced, and a medium transporting hose having excellent durability can be obtained. Because it is woven in a shape, it is also excellent in the production efficiency of hose production.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating one embodiment of a medium transport hose of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inner pipe 2 first reinforcing thread layer 3 second reinforcing thread layer 4 outer pipe 5 intermediate layer

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 3B153 AA15 AA38 AA45 BB01 CC23 DD25 FF11 FF19 GG01 GG05 3H111 AA02 BA11 BA25 CB05 CB06 CB07 CC02 CC07 CC19 DA07 DB01 EA04 EA17 4F100 AK03 AK27 AK27J AK47A28 ALAKAL AN00A AN00D AN00E BA04 BA05 BA07 BA10A BA10D BA24 DA11 DG01B DG01C DG07B DG07C EH51B EH51C GB90 JA13B JA13C JL00 YY00B YY00C

Claims (3)

[Claims] 1. A medium transport hose in which a first reinforcing yarn layer, a second reinforcing yarn layer, and an outer tube are sequentially laminated on an outer periphery of an inner tube, wherein the first reinforcing yarn layer has a spiral shape on the outer periphery of the inner tube. The second reinforcing yarn layer is constituted by reinforcing yarn wound spirally around the outer periphery of the first reinforcing yarn layer in the direction opposite to the first reinforcing layer, and the first and second reinforcing yarns are formed. The knitting density of the entire reinforcing yarn of the yarn layer is 70% or more, and the first and second reinforcing yarns are multi-twisted yarns, and both the number of lower twists and the number of upper twists are 8 times / 10 cm or more. A hose for transporting a medium, comprising: 2. The medium transport hose according to claim 1, wherein at least a part of the first twist yarn of the first and / or second reinforcing yarn layers is an aramid fiber. 3. The medium transport hose according to claim 1, wherein an intermediate layer is provided between the first reinforcing yarn layer and the second reinforcing yarn layer.