JPH01301244A - Hose for transporting refrigerant - Google Patents

Abstract

PURPOSE:To obtain a refrigerant transport hose excellent in gas imperviousness and good flexibility and piping workability, by forming the arbitrary layers or single layer among many layers constituting a tubular elastic material layer from a specific resin composition. CONSTITUTION:This refrigerant transport hose is constituted of a tubular elastic material layer 11a, which is constituted of many layers or a single layer, for allowing a refrigerant to flow and the arbitrary layers or single layer among many layers are formed from a resin composition based on a mixture of at least one of nylon 11 and nylon 12, and a saponified ethylene/vinyl acetate copolymer. In this refrigerant transport hose, for example, an outside rubber layer 12a, a fiber reinforced layer 13 and an outer tube rubber layer 14 are provided to the outside of the tubular elastic material layer 11a and spiking holes 15 for escaping the gas stagnated between the layers are extended from the outer tube rubber layer 14 to the fiber reinforced layer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a bow for transporting refrigerant, and particularly to a bow for use in piping for car coolers, air conditioners, etc. of automobiles.

[Conventional technology]

As a hose for transporting a refrigerant such as Freon gas, a hose having a three-layer structure including an inner tube rubber layer 1, a fiber reinforced layer 2, and an outer tube rubber layer 3 is known, as shown in FIG. 5, for example.

The inner tube rubber layer 1 is usually made of acrylonitrile-butadiene copolymer (NBR) or chlorosulfonated polyethylene rubber (C3M), the fiber reinforced layer 2 is made of polyester fiber, etc., and the outer tube rubber layer 3 is made of ethylene. - It is formed from propylene-diene rubber (EPDM) or chloroprene rubber (CR). Also, 15
is a spiking hole, which extends from the surface of the outer tube rubber layer 3 to the fiber reinforced layer 2, and is provided so that the permeated Freon gas from the inner tube rubber layer 1 escapes to the outside and does not accumulate between the layers. When gas remains between each layer, that portion swells, causing delamination.

In this way, a hose that is entirely composed of rubber layers except for the fiber reinforcement layer 2 is flexible and has excellent workability for piping, etc. However, since each rubber layer has gas permeability, it is difficult to handle refrigerant gas. gradually leaks from the hose and decreases. Therefore, if a constant cooling capacity is to be maintained, gas charging must be performed frequently, which causes many problems in terms of maintenance.

In response, it has been proposed to use a resin material with excellent gas impermeability to prevent gas leakage from the hose. Examples of the above-mentioned resin materials include saponified products of ethylene-vinyl acetate copolymer, but such resin materials generally have high rigidity and have the disadvantage that when used as hose materials, the flexibility of the hose is significantly impaired. are doing. Of course, since the resin material mentioned above has excellent gas impermeability, it is possible to make it very thin and use it together with other rubber layers, but even in this case, the flexibility of the hose will still be satisfactory. It's not something I can do.

[Problem that the invention seeks to solve]

As described above, all conventional hoses have advantages and disadvantages as hoses for transporting refrigerant, and the reality is that no hose of quality that satisfies gas impermeability and flexibility at the same time has been obtained.

The present invention has been made in view of these circumstances, and an object of the present invention is to provide a refrigerant transport hose that has excellent gas impermeability, is flexible, and has good piping workability.

[Means for solving problems]

In order to achieve the above object, the refrigerant transport hose of the present invention has a tubular elastic material layer through which the refrigerant flows, which is composed of multiple layers or a single layer, and wherein the tubular elastic material layer is composed of an arbitrary layer or layers of the multilayers constituting the tubular elastic material layer. Single layer is nylon 11 and nylon 1
2 and a saponified ethylene-vinyl acetate copolymer as a main component. In addition, in this invention, "consisting of a main component" is used to include the case where the whole is composed only of the main component.

[Effect]

That is, as a result of repeated research on combinations of various resin materials and rubber materials as tubular elastic material layer forming materials, the present inventors found that saponified ethylene-vinyl acetate copolymer and
This invention was achieved by discovering that by combining one or both of nylon 11 and nylon 12, it is possible to simultaneously satisfy both gas impermeability and flexibility, which were previously impossible to satisfy at the same time.

Next, this invention will be explained in detail.

An example of a refrigerant transport hose according to the present invention is shown in FIG. In the figure, lla is a resin layer formed of a resin composition consisting of at least one of nylon 11 and nylon 12 and a saponified ethylene-vinyl acetate copolymer;
2a is an outer rubber layer, 13 is a fiber reinforced layer, 14 is an outer tube rubber layer, and 15 is a spiking hole for releasing gas remaining between the layers to the outside, which extends from the outer tube rubber layer 14 to the fiber reinforcement 113.

The resin layer 11a and the outer rubber layer 12a together form a tubular elastic material 711 corresponding to the inner tube rubber layer 1 shown in FIG.
constitute a.

The resin layer 11a is formed of a resin composition mainly composed of a saponified ethylene-vinyl acetate copolymer and a small amount of nylon 11 and nylon 12 (hereinafter abbreviated as "nylon polymer"), It is considerably more flexible than conventional resin materials and has excellent gas impermeability.

As the saponified ethylene-vinyl acetate copolymer,
Usually, the ethylene-containing '0-ffi is 80 mol% or less and the saponification degree of vinyl acetate is 90 mol% or more. That is, the ethylene content exceeds 80 mol%,
This is because, in a saponified ethylene-vinyl acetate copolymer in which the saponification degree of vinyl acetate is less than 90 mol%, the effect of gas impermeability tends to become insufficient.

In addition, nylon 11. used together with the saponified ethylene-vinyl acetate copolymer. Although nylon 12 is a resin material, it has flexibility, and by combining it with the saponified ethylene-vinyl acetate copolymer,
It can be a molded product that is flexible and highly gas impermeable. This invention uses this material as the inner tube material of the hose to obtain a refrigerant transport hose that is both flexible and gas-impermeable, and this is the most distinctive feature.

The mutual composition ratio of (E) and (N) in the resin composition whose main components are the saponified ethylene-vinyl acetate copolymer (E) and the nylon polymer (N) is NmW quasi-T:
E/N=90/10~5/9'5, especially 80/20~1
It is preferable to set it within the range of 0/90. If more than 90% by weight of the saponified ethylene-vinyl acetate copolymer is blended, the gas impermeability will be extremely good, but the rigidity of the resulting hose will increase, which is undesirable in terms of piping work. On the other hand, if less than 5% by weight of the saponified ethylene-vinyl acetate copolymer is added, the flexibility of the hose will be good, but the gas impermeability will be insufficient, which is not preferable.

In addition, the above saponified ethylene-vinyl acetate copolymer and...
The method for obtaining the polymer composition can be similar to the method for obtaining ordinary resin compositions. For example, it can be obtained by triblending pellets of a saponified ethylene-vinyl acetate copolymer and pellets of a nylon polymer, and then kneading the resultant mixture in a twin-screw extruder. In addition, the resin composition may contain C3M, CPE, CHC, CHR, CA-II, if necessary.
There is no problem in containing halogenated rubber such as R, rubber such as EPDM, NBR, etc. In this case, the total amount of saponified ethylene-vinyl acetate copolymer and nylon polymer ff
The mixing ratio of l (X) and the rubber (Y) is preferably set in the range of X/Y=60/40 to 10010 on a weight basis.

When forming resin N11a using the above resin composition,
The thickness of the layer is 0.05-1. It is preferable to set it to about Oram. That is, if the thickness is less than 0.05 mm, the gas impermeability effect will not be sufficient; This is because if it exceeds Orrrm, the gas impermeability will be good, but the rigidity of the hose will become high. However, the purpose of the hose,
It can be set appropriately by taking into consideration the usage environment, characteristics of other layers, etc.

The outer rubber layer 12a is usually made of a rubber material such as that used for the inner tube of a hose for transporting refrigerant. Examples of the above-mentioned rubber materials include NBR, C3M, and EP.
DM, chlorinated polyethylene (CPE), epichlorohydrin rubber (CHC.

CHR), chlorinated butyl rubber ((1-IIR), etc.).

The fiber reinforcing layer 13 may be one that is used in ordinary hoses, and is formed by braiding, spiral weaving, etc. of yarn mainly composed of synthetic fibers such as polyester fibers and aramid fibers.

Further, the outer tube rubber layer 14 is a layer exposed to the outside, and from the viewpoints of heat resistance, weather resistance, and water permeability, it is preferable to use EPDM. However, other rubber materials may also be used.

The refrigerant transport hose of the present invention can be manufactured by forming each of the layers described above, for example, in the following manner.

(1) A molten resin obtained by heating and melting a resin composition for forming the resin layer 11a on a rubber mandrel is extruded from a resin extruder and cooled.

(2) Next, after applying an adhesive to the outer peripheral surface of the resin layer 11a, an unvulcanized rubber composition for forming the outer rubber Fi12a is extruded from an extrusion molding machine to form the inner two-layer structure. A tube (tubular elastic material layer) is obtained.

(3) After applying an adhesive to the outer circumferential surface of the inner tube, the yarn for the fiber reinforcement layer 13 is braided, etc. to form the fiber reinforcement layer 13.
form.

(4) After applying an adhesive to the outer circumferential surface of the fiber reinforced layer 13, an unvulcanized rubber composition for forming the outer tube rubber layer 14 is extruded thereon using an extrusion molding machine.

(5) After the laminated tubes are vulcanized and bonded to integrate them, the mandrel is removed. In addition, the vulcanization conditions are usually a temperature of 1
The temperature is set at 45-170°C for 2 hours and 30-90 minutes.

In the above manufacturing method, the thickness of the resin layer 11a is preferably 0.05 to 1.0 mm, as described above.

Furthermore, the thickness of the outer rubber layer 12a is 1 ml of the above resin.
From the viewpoint of elastically holding a, it is preferable to set it in the order of 1 to 3.

In addition, the thickness of the outer tube rubber layer 14 is determined by considering water permeability.
It is preferable to set it to 1 to 2.5 degrees.

In the thus obtained refrigerant transport hose, the resin layer 11a of the tubular elastic material layer is formed of a special resin composition consisting of a saponified ethylene-vinyl acetate copolymer and an iron polymer. Therefore, this resin composition has excellent flexibility and gas impermeability, which, in combination with the layered structure described above, provides optimal performance for a refrigerant transport hose.

Note that the refrigerant transport hose of the present invention is not limited to one in which the inner tube (tubular elastic material layer) has a two-layer structure as shown in Fig. 1, but can also have a structure as shown in Figs. 2 to 4. You can. That is, in the case shown in Fig. 2, the inner tube is made of resin Jm made of saponified ethylene-vinyl acetate copolymer and nylon polymer.
11B. In addition, the one in Figure 3 has an inner tube with a three-layer structure, and the innermost layer is the inner rubber layer 10.
An intermediate resin layer 11 made of at least one of nylon 11 and nylon 12 and a saponified ethylene-vinyl acetate copolymer is formed on the outside thereof.
A rubber layer 12 is arranged on the outside of the rubber layer 1. The inner rubber layer 10 is formed of the same rubber material as the outer rubber layer 12, and has the role of maintaining sealing properties for joints such as nipples. Further, in the case shown in FIG. 4, contrary to the case shown in FIG. 1, the innermost layer is a rubber layer 10a, and a resin layer 11a is arranged outside of the rubber layer 10a. Of these,
The sealing properties for joints such as nipples are good for those shown in Figures 3 and 4, in which the innermost layer is made of a rubber material.
In addition, the fewer the number of layers and the simpler the structure, the lower the cost, so these can be used depending on the purpose, and each can provide a predetermined effect.

[Effects of the Invention] As described above, the refrigerant transport hose of the present invention is highly flexible and highly gas impermeable, and therefore requires sealing performance and gas impermeability for a long period of time. It has characteristics that make it ideal for car coolers and air conditioner hoses.

Next, examples will be described together with comparative examples.

(Examples 1 to 4, Comparative Examples 1 to 3) Hoses having the configurations shown in Table 1 below were manufactured according to the manufacturing method described above. In addition, when the inner tube had a three-layer structure, first, an unvulcanized rubber composition for forming the inner rubber layer 10 was extruded from an extrusion molding machine onto a rubber mandrel to obtain a tubular body. The rest was manufactured according to the manufacturing method described above.

(Hereinafter, blank space) Each of the hoses thus obtained was evaluated for flexibility and gas impermeability. The results are shown in Table 2 below.

In addition, each evaluation was performed as follows.

Cut the hose into 300 mm or 400 mm and -
The end was fixed on a flat plate and the other end was bent to reach the flat plate, and the bending stress was measured and evaluated. A smaller value indicates greater flexibility.

Gas impermeability> Cut the hose into 500 mm pieces, fill with 40 g of Freon 12, seal both ends, and heat this in an atmosphere of 100°C for 7 days.
After being left for 2 hours, the entire weight was measured and compared with the initial weight to determine the number of grams of Freon permeated and evaluated. The smaller the value, the better the gas impermeability.

(Left below) From the above results, it can be seen that the practical products have both flexibility and gas impermeability. On the other hand, in Comparative Example 1, in which the inner tube was composed of a single layer of NBR, a large amount of gas permeated therethrough, making it impractical. In addition, the two comparative examples in which the intermediate resin layer was formed only with saponified ethylene-vinyl acetate copolymer had excellent gas impermeability but poor flexibility; compared with the intermediate resin layer formed only with nylon 11. On the contrary, it can be seen that the product of Example 3 has good flexibility but poor gas impermeability.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of an embodiment of the present invention, FIG.
4 and 4 are electrical cross-sectional views of other embodiments, and FIG.
The figure is a longitudinal cross-sectional view of a conventional product. 1a...Tubular elastic agent layer 11a...Resin layer 12a
...Outer rubber layer 13...Fiber reinforcement layer 14...
Outer tube rubber layer patent applicant Tokai Rubber Industries Co., Ltd. Agent Patent attorney 4 Yukihiko Ugo Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) The tubular elastic material layer through which the refrigerant flows is composed of multiple layers or a single layer, and any layer or single layer of the multilayers constituting the tubular elastic material layer is nylon 11 and nylon 1.
1. A hose for transporting a refrigerant, characterized in that it is formed of a resin composition containing as a main component a mixture of at least one of the above and a saponified ethylene-vinyl acetate copolymer.