JPH0243044A - Gas barrier multi-layer hose - Google Patents

Abstract

PURPOSE:To obtain a hose, in which almost no gas leakage develops and which is excellent in both pressure resistance and flexing resistance by a method wherein gas barrier resin layer-containing tape-like matter is wound to the outside of an inner tube under the condition that the potential tensile stress, which is 5-70% of the tensile yield stress of a reinforcing layer, is given to the reinforcing layer. CONSTITUTION:Gas barrier tape-like matter 2 is laminatingly wound round an inner tube 1, which consists of at least one ply. The tape-like matter 2 has barrier property mainly against gases such as Freon gas, CO2 gas, O2 gas or N2 gas. Further, a reinforcing layer 4 is provided directly or through an intermediate layer to the outside of the winding layer 3 of the tape-like matter 2. Furthermore, at least one ply of flexible outer layer 5 is provided on the reinforcing layer 4. By providing the reinforcing layer 4 and inherently giving the stress, which is 5-70% of the tensile yield stress of the reinforcing layer, to the reinforcing layer, the laminated part of the tape can be tightened from outside, resulting in increasing the planar pressure of the laminated surface and allowing to enhance the anti-gas leaking effect. And, the reinforcement through the provision of a reinforcement layer 6 is more effective.

Description

[Detailed Description of the Invention] A-1 The present invention relates to a gas barrier multilayer hose with excellent pressure resistance and flexibility, and is extremely suitable as a hose that requires barrier performance, such as for various gas bodies or gaseous liquids. Useful.

B, 'O' Traditionally, flexible resin hoses, such as rubber hoses, use flexible resins such as rubber and elastomer resins, and if reinforcing materials with high strength and high elasticity are used, , in the form of a thread, braid, cross, etc., so as not to lose its flexibility. In recent years, there has been a growing demand for such flexible hoses to have gas barrier performance against various gases such as freon, and hoses that have a gas barrier resin layer as one layer of the hose (usually as an inner tube) are also being considered. However, since high gas barrier resins such as ethylene-vinyl alcohol copolymer (EVOH), polyamide, and polyethylene terephthalate (PET) have high elastic modulus and are hard, such hoses are inevitably low in flexibility. There is a drawback. In order to solve these problems, a method of wrapping a tape-like material made of gas barrier resin has been studied and applied. Although such hoses are flexible, there are drawbacks to multilayer hoses wrapped with gas barrier tape.
There is a problem of gas leakage from the gaps between the stacked and wound tapes. Particularly when the internal pressure is low or when the gas temperature is low, the tightening effect between the tapes cannot be expected, and gas leakage from between the gas barrier tape becomes a problem. Therefore, there is a concern that fatigue phenomena may occur particularly in severe bending parts, repeated bending parts, or parts where there is a lot of vibration, resulting in unexpected gas leaks. These problems are exacerbated when tapes with higher barrier properties are used, since these tapes typically have a high modulus and are hard.

Problem to be Solved by Akira C1 The present invention solves the problem of increasing the gap between the layers of the gas barrier tape material regardless of internal gas pressure and temperature conditions, and even under adverse conditions such as bending and bending fatigue. First, it is an object of the present invention to obtain a gas barrier multilayer hose that hardly causes gas leaks and has excellent pressure resistance and bending resistance.

D. The present invention provides a multilayer hose having a layer of tape-like material wrapped around the outside of the inner tube including a gas barrier resin layer, in which the tape-like material has a tensile yield stress of 5 to 70. % latent tensile stress.

E. Detailed Description In the present invention, a tape-like article containing a gas barrier resin layer refers to a tape-like article consisting of a single layer of a gas barrier resin layer.
Alternatively, it refers to a tape-like product (Fig. 2) consisting of a composite layer of a gas barrier resin layer and a reinforcing layer, but the tape-like product composed of the latter composite layer can have a larger latent tensile stress. Therefore, it is effective.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a perspective view showing an example of a multilayer gas barrier hose of the present invention. A gas barrier tape-like material 2 is laminated and wrapped around an inner tube 1 consisting of at least one layer. This tape-like material 2 mainly contains Freon, CO
2, O2, or N! The gas barrier resin has gas barrier properties such as gas barrier polyamide, EVOH, gas barrier polyester, and resin sheets coated with or vapor-deposited with metal. Further, as this gas barrier resin layer, an unstretched film, a -axially stretched film, or a biaxially stretched film is used. Further, on the outside of the wrapped Fi3 of the gas barrier tape-like material 2, a reinforcing layer 4 is provided either directly or with an intermediate layer interposed therebetween, and furthermore, at least one flexible outer layer 5 is provided. Here, the reinforcing layer is usually composed of a thread-like material (net-like, braid-like, cloth-like), or the like. Further, as the flexible outer layer 5, rubber, various elastomers, and various flexible resins are typically used.

A hose constructed by winding such a gas barrier tape-like material 2 has the advantage that it can maintain flexibility to some extent due to the misalignment between the gas barrier layers, but it has the disadvantage that gas leaks from the gaps between the laminated tapes. In particular, there is a risk that gaps will increase in areas that are severely bent or that are subjected to repeated bending, leading to unexpected gas leaks.

In order to solve these problems, the present invention has been made through various studies and it has been discovered that the above problems can be solved by constantly maintaining the interlayer pressure of the gas barrier tape at a certain level or higher. Ta.

That is, winding is a method in which a large tensile stress is applied to the laminated gas barrier tape-like material so that a latent tensile stress of 5 to 70% of the tensile yield stress is applied. Specific methods for this include increasing the winding stress of the tape to impart latent stress to the laminated tape after winding, or wrapping a tape with a large heat shrinkage force and then heat-treating it. , a method of generating and applying latent stress.

In order to impart sufficient tension to the gas barrier tape, it is effective to reinforce the gas barrier tape by providing a reinforcing layer 6 as shown in FIG.

Furthermore, by providing a reinforcing layer 4 on the outside of the wrapping layer 3 of the gas barrier tape, the layered portion of the barrier tape can be tightened from the outside by internally imparting a large tensile stress to the reinforcing layer 4. Thereby, the surface pressure of the laminated surface of the gas barrier tape-like material can be improved, and the gas leak prevention effect can be further enhanced.

The stress inherent in the gas barrier tape-like material and the reinforcing layer described above is determined by the conditions of the fluid used and the hose configuration. Although it is preferable to apply a high tensile stress, there is a concern that the tape may break during use such as bending.
It is preferable to adjust the tensile stress so that a potential tensile stress of ~70%, more preferably 10-50% is applied.

Note that the potential tensile stress of a tape-like object is calculated by subtracting the length of the tape-like object when it is released from the wrapping from the length of the tape-like object when it is wrapped. This is a value calculated using an SS (stress response strain) curve. Moreover, the tensile yield stress is a value determined by ASTM-D-638.

The inner tube 1 is a white tube made of at least one layer that forms the inner flow path of the hose, and it is of course necessary to withstand the fluid conditions used, but it is also important that it not be damaged by tightening with a tape-like object.

The inner tube is made of flexible polyamide,
Elastomer resin, rubber, etc. are preferably used.

FIG. 2 is a perspective view showing an example of a gas barrier tape used in the present invention, which is a tape made of a composite layer in which a reinforcing layer 6 is provided between gas barrier resin layers 7. . Like the reinforcement layer 4, the reinforcement layer 6 is made of a thread-like material or a sheet-like material.

The multilayer hose of the present invention is used for various gas hoses such as automobile cooler hoses, propane gas hoses, medical hoses, hot water circulation heating hoses, etc., and in particular, Freon 12, Freon 22.02, CO
2. Suitable for use as a barrier hose for N and gas.

F1 Effects of the Invention The multilayer hose of the present invention does not increase the gap between the gas barrier tape layers even under adverse conditions such as bending or bending fatigue.
There is almost no gas leakage, and it also has excellent pressure resistance and bending resistance.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a multilayer hose according to the present invention, and FIG. 2 is a perspective view of a tape-like article made of a composite layer of a gas barrier layer and a reinforcing layer used in the present invention. 1... Inner tube 2... Gas barrier tape-like material 3... Winding layer of gas barrier tape-like material 4... Reinforcement layer 5... Flexible outer layer 6... Reinforcement layer 7...Gas barrier resin layer Figure 1 Patent applicant RiRa Shi Co., Ltd.

Claims (3)

[Claims] (1) A multilayer hose having a layer of tape-like material wrapped around the outside of the inner tube including a gas barrier resin layer, in which the tape-like material has a latent tensile stress of 5 to 70% of the tensile yield stress. Gas barrier multilayer hose. (2) The gas barrier multilayer hose according to claim 1, further comprising a reinforcing layer on the outside of the wrapped layer of the tape-like material. (3) The gas barrier multilayer hose according to claim 1 or 2, wherein the tape-like material is a composite layer of a gas barrier resin layer and a reinforcing layer.