JPH0737835B2 - Acid resistant hose - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hose having acid resistance, and is particularly effective when used as a cooler hose as a refrigerant pipe of an automobile air conditioner.

[Conventional technology]

The cooler hose A in the conventional automobile air conditioner is the second
A reinforcing thread layer 2 is wound around an inner rubber tube 1 as shown in the figure, and an outer rubber 4 is coated on the reinforcing thread layer 2. In such a hose A, especially when the internal fluid is a gas, such as a cooler hose, the refrigerant gas that gradually permeates from the inside of the hose stays in the intermediate layer having the reinforcing thread layer 2 and the inner rubber tube 1 and the outer rubber 4 May peel off. Therefore, as disclosed in, for example, Japanese Patent Laid-Open No. 59-1891, a plurality of through holes 5 are provided in the outer rubber 4 to allow the refrigerant gas to escape. Further, the hole 5 has a function of gently releasing the refrigerant gas to the outside air even in an emergency such as a case where a through crack is generated in the inner rubber tube 1. In such a case, if the hole 5 is not provided, the outer surface rubber 4 bursts with a loud sound. However, when the hose A having such a structure is used for, for example, an automobile and arranged near the battery in the engine room, vibration of the vehicle,
The battery liquid (diluted sulfuric acid liquid) is scattered on the surface of the hose due to overcharging and the like, and penetrates through the hole 5 on the outer rubber 4 to deteriorate the reinforcing thread layer 2 and significantly reduce the pressure resistance of the hose. Therefore, as shown in FIG. 3, a protective cover 6 is put on the outside of the hose A to prevent the battery liquid from entering through the hole 5.

[Problems to be solved by the invention]

However, such a conventional hose covered with the protective cover 6 has problems that productivity is poor because the protective cover is not easily assembled and the protective cover itself is expensive. Further, as the usage environment is becoming more and more severe year by year, there is an increasing need for a hose that is highly productive and can economically maintain its performance for a long period of time.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a hose excellent in acid resistance without requiring a protective cover.

[Means for solving problems]

To achieve the above object, in the first invention of the present invention, an inner rubber tube, a reinforcing thread layer formed on the inner rubber tube, and an outer rubber formed so as to cover the reinforcing thread layer. The outer surface rubber is provided with holes penetrating the inner and outer circumferences thereof, and the reinforcing thread layer is made of a fiber having excellent acid resistance.

In the second invention, the inner rubber tube, the reinforcing thread layer formed on the inner rubber tube, the intermediate rubber layer formed so as to cover the reinforcing thread layer, and the intermediate rubber layer An outer surface rubber formed so as to cover the intermediate rubber layer and the outer surface rubber are provided with holes penetrating the inner and outer circumferences thereof, and the reinforcing yarn layer is formed of fibers having excellent acid resistance. In this case, a technical means is adopted in which the intermediate rubber layer is made of rubber having high water absorption.

[Action]

Since the hose according to the first aspect of the present invention has the above technical means, the reinforcing yarn layer is made of a fiber having excellent acid resistance even when acid scatters on the surface of the hose and an acidic liquid enters the holes of the outer rubber. As a result, the deterioration of the reinforcing yarn is minimal due to the acid resistance of the fiber itself, and the strength of the hose can be maintained for a long period of time.

Further, in the hose of the second invention, when the acidic liquid scattered on the surface of the hose enters the hose through the holes, the intermediate rubber layer absorbs the acidic liquid, and the penetration into the reinforcing yarn layer is greatly reduced, and the reinforcing yarn layer Can be prevented. Furthermore, even when the acid absorbed in the intermediate rubber layer is slightly released due to diffusion etc. and penetrates into the reinforcing yarn layer, deterioration of the reinforcing yarn is extremely small due to the acid resistance of the fiber having excellent acid resistance and the strength is maintained for a long time. be able to.

〔Example〕

 Hereinafter, the present invention will be described in detail based on examples.

The structure of the acid resistant hose according to the present invention is shown in FIG.
An explanation will be given based on (b).

A reinforcing thread layer 2 having excellent acid resistance is wound around an inner rubber tube 1, an intermediate rubber layer 3 having high water absorption is provided thereon, and an outer rubber 4 is further coated thereon to form an intermediate rubber layer 3 and an outer rubber 4 A hole 5 is formed through the hole. Here, aramid fiber or fluorine fiber can be used as the acid resistant reinforcing yarn 2, and acrylonitrile butadiene rubber, urethane rubber or the like having high water absorption is preferably used as the intermediate rubber 3. However, the intermediate rubber layer 3 can be selected depending on the amount of the acid that penetrates. When the acid penetrates very little, the intermediate rubber layer 3 can be omitted and only the acid resistant reinforcing yarn layer 2 can be used. If the wall thickness of the cooler hose is too thin, the water absorption capacity is low. If it is too thick, the wall thickness of the hose increases and the flexibility is impaired. Therefore, the thickness of this intermediate rubber layer is 100 μm to 1 mm. It is preferable.

Next, the manufacturing process of the hose will be described. The extrusion of the inner rubber tube 1 and the braiding of the reinforcing yarn layer 2 are no different from those of the conventional hose. As a method of coating the intermediate rubber layer 3, when the wall thickness is large, the intermediate rubber layer 3 may be coated by extrusion similarly to the outer surface rubber 4. When the wall thickness is thin, as shown in FIG. The hose may be dipped in the rubber solution 8 of the intermediate rubber 3 housed in the dipping tank 7 and then dried in the drying oven 9 to form a coating.

The first embodiment is a hose in which acrylonitrile butadiene rubber is used for the inner rubber tube 1, aramid fibers are braided thereon to form a reinforcing yarn layer 2, and the outer rubber 4 is covered with ethylene propylene rubber. In the second embodiment, the reinforcing yarn layer 2 is formed from the aramid fiber used in the first embodiment, and then the intermediate rubber layer 3 of acrylonitrile butadiene rubber is coated with 1 mm,
The hose is covered with ethylene propylene rubber as the outer rubber 4 thereon.

Next, a comparison between the above-described first and second embodiments and the conventional hose performed by the inventor will be described. At that time, acrylonitrile butadiene rubber was used for the inner rubber tube 1, polyester fiber was wound up on the reinforcing yarn layer 2, and a hole 5 was formed on the polyester fiber.
A conventional hose coated with ethylene propylene rubber as the outer rubber 4 having the holes formed therein is used as a comparative example.

For the above-mentioned first example, second example, and comparative example, sulfuric acid diluted to 40% was added from the hole 5 opened on the surface of the outer rubber 4.
The strength of the reinforcing yarn 2 after 2 cc injection and heat aging at 120 ° C. was measured. The results are shown in Table 1.

As can be seen from the table, the first and second examples have sufficient strength even after a lapse of 200 hours in the heat aging test at 120 ° C., and the effect of the acid resistant reinforcing yarn is recognized. Furthermore, in the second embodiment in which the intermediate rubber layer 3 is applied, deterioration of the reinforcing yarn is extremely small due to the water absorption effect, and the life of acid resistance is significantly improved.

〔The invention's effect〕

As described above, according to the first invention of the present invention, the reinforcing thread layer composed of the fiber having excellent acid resistance is provided, and according to the second invention, the reinforcing thread layer is composed of the rubber having high water absorption. Since the rubber layers are combined, even if an acid penetrates through the holes in the outer rubber surface of the hose, its strength can be maintained for a long time and the pressure resistance of the hose can be maintained. Further, the structure of the hose of the present invention hardly lowers the efficiency in manufacturing the hose, and a large cost reduction effect can be obtained as compared with the conventional hose covered with a protective cover. In addition, as compared with the one in which each unit filament of the reinforcing yarn layer is coated with an acid-resistant treatment agent such as a urethane-based adhesive as in JP-A-61-65984,
According to the present invention, it is possible to manufacture an acid-resistant hose at a significantly low cost without adding any special steps such as a step of coating the acid-resistant treatment agent and a drying step after coating the treatment agent.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. (A) is a sectional view, (b) is a partially cutaway perspective view, and FIG. 2 is a partially cutaway perspective view showing an example of a conventional hose. FIG. 4 is a front view showing a conventional hose covered with a protective cover, and FIG. 4 is a schematic view showing an embodiment of a coating process of an intermediate rubber layer in the present invention. 1 …… Inner rubber tube, 2 …… Reinforcing thread layer, 3 …… Intermediate rubber layer, 4 …… Outer rubber, 5 …… Hole, A …… Hose.

Claims (4)

[Claims] 1. An inner surface rubber tube, a reinforcing thread layer formed on the inner surface rubber tube, and an outer surface rubber formed so as to cover the reinforcing thread layer. An acid resistant hose characterized in that a hole penetrating the circumference is provided, and the reinforcing yarn layer is composed of fibers having excellent acid resistance. 2. The acid-resistant hose according to claim 1, wherein the fiber having excellent acid resistance is an aramid fiber. 3. An inner rubber tube, a reinforcing thread layer formed on the inner rubber tube, an intermediate rubber layer formed to cover the reinforcing thread layer, and an intermediate rubber layer covering the intermediate rubber layer. An outer surface rubber formed as described above is provided, the intermediate rubber layer and the outer surface rubber are provided with holes penetrating the inner and outer circumferences thereof, and the reinforcing yarn layer is composed of fibers having excellent acid resistance, The acid resistant hose, wherein the intermediate rubber layer is made of rubber having high water absorption. 4. The acid resistant hose according to claim 3, wherein the fiber having excellent acid resistance is an aramid fiber, and the rubber having high water absorption is an acrylonitrile butadiene rubber.