JP3070325B2 - Acid fluid high pressure rubber hose - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acidic fluid high pressure rubber hose.

[0002]

2. Description of the Related Art In a high pressure rubber hose, liquid oil flows as a pressure transmission medium in the hose.

In this type of high-pressure rubber hose, a braided layer is provided as a reinforcing layer on an inner rubber tube, and the braided layer is coated with an outer rubber.

Here, the inner rubber tube is made of nitrile rubber, styrene butadiene rubber,
Chloroprene rubber, ethylene propylene diene rubber and the like are used.

[0005] The braided layer is braided with yarns of high-strength rayon, polyester fiber, polyvinyl alcohol fiber, polyamide fiber, aramid fiber and the like.
The braided layer may be a single layer or a multiple layer. When the braided layer is a multilayer, there are a reinforcing yarn using the same yarn and a reinforcing yarn combining different yarns. When the braided layer is a multilayer, it is customary to provide an intermediate rubber layer such as natural rubber between the braided layers.

As the outer layer rubber, chloroprene rubber, ethylene propylene diene rubber and the like having excellent mechanical properties and weather resistance are used.

[0007]

In a high-pressure rubber hose, liquid oil flows as a pressure transmission medium in the hose.

[0008] Naturally, high pressure rubber hoses are made robustly to withstand these high pressure fluids. However, when observing the high pressure rubber hose from a microscopic view,
It has been found that a very small amount of liquid oil in the hose permeates the inner rubber tube layer and diffuses to the braided layer.

For this reason, when the liquid oil is an erodible substance that erodes the braid layer, for example, an acidic high-pressure fluid, the braid layer is eroded. Of course, even if the high-pressure fluid becomes acidic due to the reaction with moisture, the braided layer is similarly eroded. In this case, when the high-pressure rubber hose is used at a high temperature for a long period of time, a very small amount of water permeates into the braided layer via the outer rubber layer.

In general, since a fiber material has low resistance to an acidic substance, when a high-pressure rubber hose is used for a long period of time under the above-mentioned circumstances, a reduction in fatigue resistance is inevitable.

The present invention has been made in view of such a point, and an object of the present invention is to solve the above-mentioned disadvantages of the prior art and to withstand pressure and fatigue life even when an acidic high-pressure fluid is used. To provide a high-pressure rubber hose capable of greatly improving the pressure.

[0012]

The gist of the present invention is to provide a high-pressure rubber hose in which a braided layer is provided on an inner rubber tube and the outer rubber is coated on the braided layer.
Braided layer is acidified fluid pressure hose, characterized in that formed by impregnating the 10g of the braided layer with an adhesive such as _P H of the dipping water is 9 or more when dipped in water 100 ml.

[0013] As the adhesive agent in the present invention, alkaline aqueous dispersion type adhesive shows a higher _P H9 or water-soluble adhesive, or a braided yarn or braid layer 10g after the impregnation treatment by immersing in water 100ml with water dispersed state When its soaked water
_P H is a solvent type adhesive or a solvent-free adhesive such as a 9 or more.

Here, as the alkaline substance, N
Inorganic strong alkalis such as aOH, KOH and Ca (OH) ₂ are effective, but organic bases such as amines and ammonium salts are also effective.

These alkaline substances can be directly mixed into the adhesive, or the alkaline substances may be microencapsulated with a water-soluble polymer film or a low melting point heat-fusible polymer.

The impregnation of the braided layer may be performed at the yarn stage, or may be performed after braiding.

As the impregnation method, there is a method of impregnating the yarn or the braided layer with the above-mentioned alkaline adhesive, or a method of first impregnating the yarn or the braided layer with only an alkaline substance and then impregnating the upper layer with a non-alkali adhesive. There is a method of processing.

In the latter case, the non-alkaline adhesive is a water-soluble polymer such as polyvinyl alcohol, methylated cellulose, water-soluble polyester or the like which dissolves by moisture absorption, or a polymer adhesive or a porous adhesive having a high water permeability. desirable.

The acidic high-pressure fluid is a mere acidic fluid substance, and usually keeps neutrality, but becomes acidic due to moisture absorption or the like.

[0020]

SUMMARY OF acidic fluid pressure rubber hose of the present invention, the braided layer by the impregnation with an adhesive such as _P H of the dipping water is 9 or more when dipped in water 100 ml, the inner rubber layer to the braided layer Even a very small amount of acidic high-pressure fluid can effectively neutralize even if a very small amount of moisture permeates from the outer layer,
As a result, the acid deterioration of the braided layer can be completely suppressed, thereby significantly improving the pressure resistance and fatigue life characteristics of the high-pressure rubber hose.

In addition, the acidic fluid high-pressure rubber hose of the present invention does not show alkalinity when neither a very small amount of an acidic high-pressure fluid permeates from the inner rubber layer nor a very small amount of moisture from the outer layer.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the acidic fluid high pressure rubber hose of the present invention will be described with reference to the drawings.

(Example 1) A first braided layer braided with a polyvinyl alcohol fiber thread impregnated with an alkaline water-dispersed acrylic adhesive was provided on an inner rubber tube made of styrene-butadiene rubber, and then on the braided layer. And a second braided layer braided with a polyvinyl alcohol fiber yarn impregnated with an alkaline water-dispersed acrylic adhesive on the intermediate rubber layer. The outer layer rubber was coated on the two braided layers to obtain the acidic fluid high pressure rubber hose of Example 1.

FIG. 1 shows the first embodiment of the present invention thus obtained.
1 shows an acidic fluid high-pressure rubber hose.

In FIG. 1, 1 is an inner rubber tube, 2 is a first braided layer, 4 is a second braided layer, 3 is an intermediate natural rubber for preventing abrasion deterioration between the first braided layer and the second braided layer 4. layer,
Reference numeral 5 denotes an outer rubber layer formed on the second braided layer 4.

Example 2 A polyvinyl alcohol-based fiber yarn was immersed in a 5% aqueous sodium hydroxide solution, dried, and then a 20% aqueous solution of polyvinyl alcohol was applied to the polyvinyl alcohol-based fiber yarn whose surface was coated with sodium hydroxide. Impregnated and baked at high temperature, alkali ~
Polyvinyl alcohol-coated polyvinyl alcohol fiber yarn was obtained. Next, an acidic fluid high-pressure rubber hose of Example 2 was obtained in the same manner as in Example 1 except that a braided layer braided using the obtained alkali-polyvinyl alcohol-coated polyvinyl alcohol-based fiber yarn was used.

(Example 3) Except for using a braided layer braided with a polyvinyl alcohol-based fiber yarn impregnated with a solvent-free epoxy paint containing sodium hydroxide microencapsulated with water-soluble methylcellulose. An acidic fluid high pressure rubber hose of Example 3 was obtained in the same manner as in Example 1.

Comparative Example 1 A first braided layer braided with a polyvinyl alcohol fiber yarn was provided on an inner rubber tube made of styrene-butadiene rubber, and then an intermediate rubber layer composed of natural rubber was coated on the braided layer. Further, a first braided layer braided with a polyvinyl alcohol fiber yarn was provided on the intermediate rubber layer, and finally, an outer layer rubber was coated on the second braided layer to obtain an acidic fluid high-pressure rubber hose of Comparative Example 1.

Next, the thus obtained acidic fluid high pressure rubber hoses of Examples 1 to 3 and the high pressure rubber hose of Comparative Example 1 were immersed in an acidic fluid for one year in a test atmosphere at a temperature of 40 ° C. and a relative humidity of 90%. An accelerated aging test was performed.

Table 1 shows the test results.

The appearance of the hose was evaluated based on the appearance of the appearance after completion of the test.

The strength of the hose was measured by pulling a 40 cm-long test-completed hose in the longitudinal direction, and its breaking strength (kgf).
It is what was asked.

[0033]

[Table 1]

As can be seen from the test results, the high-pressure rubber hose of the comparative example suffered from poor swelling of the hose, and the hose strength was also reduced.

On the other hand, the acidic fluid high-pressure rubber hoses of Examples 1 to 3 of the present invention did not have any more than the appearance of the hose, and showed that the hose strength was excellent. Although not shown here, the acidic fluid high-pressure rubber hoses of Examples 1 to 3 of the present invention exhibited more than twice the pressure resistance characteristics of the high-pressure rubber hose of the comparative example which was excellent in the pressure resistance test.

In the embodiment of the present invention, a rubber material is used for both the inner rubber and the outer rubber, but the same applies to the case of a plastic material.

Furthermore, in the present invention, it is assumed that an acidic high-pressure fluid is flowing in the hose.
By using a fiber reinforced layer obtained by bonding the adhesives of Nos. To 6, an alkali-resistant high-pressure fluid hose can be obtained.

[0038]

As a result, the acidic fluid high-pressure rubber hose of the present invention can completely suppress the erosion and deterioration of the reinforcing layer even when an acidic fluid or a high-pressure fluid which becomes acidic by moisture absorption flows in the hose, and as a result, the pressure resistance and the fatigue resistance are reduced. Performance can be significantly improved,
It is industrially useful.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal sectional front view showing an embodiment of a high-pressure rubber hose of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner layer rubber tube 2 1st braided layer 3 Intermediate rubber layer 4 2nd braided layer 5 Outer layer rubber

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takashi Ishikawa 5-1-1 Hidakacho, Hitachi City, Ibaraki Prefecture Power System Research Laboratories Nippon Cable Co., Ltd. (56) References JP-A-4-171379 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16L 11/00-11/11

Claims (5)

(57) [Claims] 1. A high-pressure rubber hose having a braided layer on an inner rubber tube and an outer rubber coated on the braided layer, wherein the braided layer is immersed in water when 10 g of the braided layer is immersed in 100 ml of water. acidic fluid pressure hose, characterized in that the _P H is formed by impregnating with an adhesive so as to 9 or more. Wherein the acidic fluid pressure hose according to claim 1, wherein the adhesive is alkaline water-dispersible adhesive or water-soluble adhesive shows a higher _P H9 water dispersed state. 3. The high pressure hose for an acidic fluid according to claim 1, wherein the adhesive is a solvent type adhesive or a solventless type adhesive. 4. An adhesive impregnated with an alkaline substance microencapsulated with a water-soluble polymer or a low-melting heat-fusible polymer.
A high-pressure hose for an acidic fluid as described above. 5. The method according to claim 1, wherein only the alkaline substance is coated on the yarn or the braid layer, and the alkaline substance coating layer is impregnated with a water-soluble polymer adhesive or a porous polymer adhesive. Acid fluid high pressure rubber hose.