JP2000072940A - Composition for electrochemical-deterioration-resistant rubber hose and multilayer rubber hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having enhanced resistance to electrochemical deterioration by mixing an ethylene/propylene copolymer rubber with carbon black, surface-treated calcium carbonate, and an antioxidant. SOLUTION: This composition comprises 100 pts.wt. ethylene/propylene copolymer rubber, 100-200 pts.wt. carbon black, 10-100 pts.wt. surface-treated calcium carbonate, and 0.5-5 pts.wt. antioxidant. To surface-treat calcium carbonate, a resinic acid or a fatty acid is used. The antioxidant used is an amine or amine-ketone type one. In order to reduce the cost of a rubber hose resistant to electrochemical deterioration, a multilayer rubber hose 1 is formed according to the following constitution. An inner layer 2 comprising the composition is integrated with an outer layer 4 (3: reinforcing layer) comprising a rubber hose composition containing the ethylene/propylene copolymer rubber, carbon black, a softener, zinc oxide, stearic acid, a vulcanization accelerator, a vulcanizing agent, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber hose composition having resistance to electrochemical deterioration and a multilayer rubber hose capable of reducing the cost of the rubber hose.

[0002]

2. Description of the Related Art Rubber hoses, such as radiator hoses,
As materials for heater hoses and other hoses for coolant systems, EPDM (Ethylene Propylene Copolymer Rubber) has appeared on the market since its excellent weather resistance, ozone resistance and heat resistance. SBR (styrene butadiene rubber) and the like have become mainstream.

[0003] In the rubber hose, an EPDM rubber hose composition obtained by adding a filler such as carbon black, a softening agent, zinc oxide, stearic acid, a vulcanization accelerator and a vulcanizing agent to EPDM is used. EPDM-based rubber hose composition is an additive amount of the filler such as carbon black are often highly filled formulations, the level of the electrical resistance value is recognized as 10 ^{0 -} 10 ² about the conductive material .

When such a rubber hose is used in a place where an electrolyte solution such as a radiator solution is used, microcracks are formed on the inner surface of the hose during use, and the hose is sufficiently flexible and elastic. Cracks may grow and cause failures such as liquid leakage and rupture.

[0005] The generation of such microcracks is not due to heat but to electrochemical degradation caused by a weak current (Harold Schneid).
er, Hal Tucker, Eddie T. Seo `` Electrochemical Degra
dation of Coolant Hoses '' ELASTOMERICS, August, 199
2).

[0006] Resistance to electrochemical deterioration can be achieved by increasing the volume specific resistivity of the rubber hose to make it difficult for electricity to flow. However, the rubber hose with such measures reduces the filling amount of carbon black or a softening agent as a rubber compounding agent, and as a result, increases the cost of the rubber hose.

[Problem] In such a conventional rubber hose that imparts resistance to electrochemical deterioration, it is necessary to reduce the filling amount of carbon black, which is a good conductor of electricity, in order to increase the volume specific resistivity. Further, since it is necessary to reduce the filling amount of the softening agent in order to maintain the rubber hardness appropriately, there has been a problem that the cost of the rubber hose is increased by performing both of these treatments.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems in the prior art, and a specific problem to be solved is to increase the resistance to electrochemical deterioration. It is another object of the present invention to provide a rubber hose composition which is resistant to electrochemical deterioration and a multilayer rubber hose which reduces the cost of the rubber hose resistant to electrochemical deterioration.

[0009]

Means for Solving the Problems Claim 1 of the present invention
The electrochemically degradable rubber hose composition according to the above is an ethylene-propylene copolymer rubber as a base material.
100 to 200 parts by weight of carbon black,
Surface treated calcium carbonate 10-100 parts by weight, anti-aging agent
It is characterized by containing 0.5 to 5 parts by weight.

[0010] In a second aspect of the present invention, the surface treated calcium carbonate is a resin acid surface treated calcium carbonate and / or a fatty acid surface treated calcium carbonate.

[0011] The rubber hose composition according to claim 3 is characterized in that the antioxidant is an amine antioxidant or an amine-ketone antioxidant.

Further, the multilayer rubber hose according to claim 4 is
The rubber hose composition according to claim 1 is lined.

Further, the multilayer rubber hose according to claim 5 is
In layers other than the innermost layer of the multilayer rubber hose, a filler such as carbon black, a softener, zinc oxide, stearic acid, a vulcanization accelerator, and a vulcanizing agent is added to an ethylene-propylene copolymer rubber as a base material. It is characterized by having a rubber hose composition added.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. However, this embodiment is specifically described for better understanding of the gist of the invention, and does not limit the content of the invention unless otherwise specified.

As shown in FIG. 1, the rubber hose of the present embodiment forms a multilayer rubber hose 1. The multilayer rubber hose 1 includes an inner layer 2 made of an electrochemically degradable rubber hose composition (hereinafter referred to as a countermeasure material), a reinforcing layer 3 made of a reinforcing material, and a conventionally used rubber hose material ( Hereinafter, it is referred to as a general material).

The inner layer 2 comprises 100 to 200 parts by weight of carbon black based on 100 parts by weight of an ethylene-propylene copolymer rubber as a base material, and a fatty acid surface-treated calcium carbonate and / or resin acid surface as a white filler. An anti-aging material containing 10 to 100 parts by weight of treated calcium carbonate and 0.5 to 5 parts by weight of a phenylenediamine-based anti-aging agent or an amine-ketone-based anti-aging agent as an anti-aging agent is formed into a tube (or tube) to be resistant. Form a rubber hose with enhanced electrochemical degradation.

The reinforcing layer 3 is formed by forming a fiber made of a synthetic resin having a high softening point such as polyvinyl alcohol, polyester or aramid into a deformable sheet or tube (or tube) by spiral knitting, blade knitting or the like. ,
It is wound or covered on the outside of the inner layer 2.

The outer layer 4 is made of a general material obtained by adding a filler such as carbon black, a softener, zinc oxide, stearic acid, a vulcanization accelerator, a vulcanizing agent, etc. to an ethylene-propylene copolymer rubber as a base material. Is formed into a tube (or tube) shape, fitted into the outer layer of the inner layer portion 2 provided with the reinforcing layer portion 3 from the outside, brought into close contact with each other, and integrally formed.

In the method for manufacturing such a multi-layer rubber hose 1, a countermeasure material is extruded into a hollow tube with a rubber extruder to form an inner layer 2, and the inner layer 2 is passed through a mandrel (core) to form a shape. And a sheet-like reinforcing material is wound around the outer periphery of the inner layer portion 2 or a tubular or tubular reinforcing material is externally fitted to form the reinforcing layer portion 3, and further, the outer periphery of the reinforcing layer portion 3 is formed. A hollow outer layer portion 4 made of a general material is externally fitted to form a three-layered hose, and the three-layered hose is vulcanized in a vulcanizing oven to be integrated with the multi-layer rubber hose 1 containing a reinforcing material. I do.

In the composition of the countermeasure material used for the inner layer portion 2, it is advantageous that the blending amount of carbon black is 100 parts by weight or less, preferably 60 parts by weight or less in order to increase the electric resistance value. However, in order to ensure physical properties and practical performance as a rubber hose with enhanced electrochemical deterioration resistance, 100 parts by weight or more, preferably 120 to 150 parts by weight
Parts by weight.

Further, as a white filler as a countermeasure material, 10 to 100 parts by weight of fatty acid surface-treated calcium carbonate and / or resin acid surface-treated calcium carbonate is blended, whereby the electrochemical deterioration resistance is remarkably improved. At the same time, the blending unit price is reduced.

Ethylene-propylene copolymer rubber as a base material of a countermeasure material has excellent weather resistance, ozone resistance and heat resistance, so that there is no need to intentionally compound an antioxidant. By incorporating 0.5 to 5 parts by weight of an antioxidant or an amine-ketone antioxidant, the electrochemical deterioration resistance is further improved.

The outer layer 4 is made of a general material obtained by adding a filler such as carbon black, a softener, zinc oxide, stearic acid, a vulcanization accelerator and a vulcanizing agent to an ethylene-propylene copolymer rubber. Since a base material having the same quality as that of the inner layer portion 2 is used, it is possible to manufacture a rubber hose with good bonding properties and at low cost.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, specific examples of a countermeasure material and a general material will be exemplified, and the resistance to electrochemical deterioration of a rubber hose of substantially the same shape formed thereby will be described in Japanese Patent Application No. Investigation was carried out using the test method described in Hei 10-45146 (hereinafter referred to as the simplified deterioration test method).

As shown in FIG. 2, an outline of the simplified deterioration test method is as follows. An antifreeze or an antifreeze diluted with water is put into a rubber hose 1 and both ends of the rubber hose 1 are metal stoppers 12, 12.
The fittings 13 and 13 are fitted around the fitting portion and tightened to seal them. Wiring is performed between the fitting plugs 12 and 12 and the DC power supply 14 so that electricity can be supplied to the fittings. A DC voltage is applied between the metal stoppers 12 and 12 while keeping the environmental conditions constant, and the liquid leakage time is observed.

Example 1 In Example 1, the innermost layers of a single-layer hose and a multi-layer hose were formed by using a countermeasure having a rubber hose composition having the composition shown in Table 1. In this case, resistance to electrochemical deterioration was obtained. Was tested, and the results are shown in Table 1.

Examples 2 to 5 In Examples 2 to 5, 50 parts by weight of fatty acid-treated calcium carbonate and 40 parts by weight as shown in Table 2 were used for comparison with fatty acid-treated calcium carbonate.
A single-layer hose was formed by using a countermeasure material having parts by weight, 30 parts by weight, and 20 parts by weight, and the same amount of other components, and in this case, resistance to electrochemical deterioration was tested. , 2.

[Examples 6 and 7] In Examples 6 and 7, in order to compare the case where a fatty acid surface-treated calcium carbonate and a resin acid surface-treated calcium carbonate were used as white fillers, respectively, as shown in Table 2, A single-layer hose was formed using the countermeasure materials having the same blending amount, and in this case, resistance to electrochemical deterioration was tested. The results are shown in Table 2.

[Comparative Examples 1 to 3] Comparative Examples 1 and 2 are examples in which general materials not containing an antioxidant and a surface-treated calcium carbonate as a white filler were used in different amounts, as used in the prior art. Comparative Example 3 is an example in which only an anti-aging agent was added to a general material, and a single-layer hose was formed by using these materials. In this case, resistance to electrochemical deterioration was tested, and the results are shown in Table 3. Was.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

As a result, in the comparative examples, abnormalities such as cracks and liquid leakage occurred within a few hours at the longest, and within one hour when the comparative examples were short. There was no generation of micro cracks. In addition, there was no difference in durability between the single-layer rubber hose and the multilayer rubber hose, and it was confirmed that the durability against electrochemical deterioration of the multilayer rubber hose had the same durability as the durability of the single-layer rubber hose. .

Regarding the characteristics of the compounding agent, the durability tends to increase as the amount of the surface-treated calcium carbonate, which is a white filler, increases in the range of a predetermined amount. No abnormalities such as cracks were observed even after 5 hours or more, and no abnormalities were observed after 96 hours when the durability was high. It was also confirmed that the durability of the antioxidant increased as the amount of the antioxidant increased in the range of the predetermined amount.

[Alternative Embodiment] This embodiment or example has been specifically described for easy understanding of the present invention, but is not intended to limit the present invention. The mode is not limited, and may be changed as appropriate. For example, in the embodiment, an example in which the multilayer rubber hose has three layers has been described. However, four or more layers may be used, and if the cost is high, a single layer may be used. Furthermore, the outer layer part 4 of the multi-layer rubber hose is the inner layer part 2.
Although the same material as the base material was used, all other usable materials can be used.

[0036]

As described above, in the rubber hose composition according to the first aspect of the present invention, the ethylene-propylene copolymer rubber is used as a base material.
100 to 200 parts by weight of carbon black,
Surface treated calcium carbonate 10-100 parts by weight, anti-aging agent
By blending 0.5 to 5 parts by weight, the durability of the rubber hose against electrochemical deterioration is improved, and even if the rubber hose formed in a single layer or a multilayer is used where an electrolyte solution such as a radiator liquid is used, Can withstand the use of.

In the rubber hose composition according to the present invention, the surface-treated calcium carbonate is preferably a resin acid-treated calcium carbonate and / or a fatty acid surface-treated calcium carbonate. The deterioration property is remarkably improved, and the compounding unit price can be reduced.

Further, in the rubber hose composition according to the third aspect, the antiaging agent is an amine-based antiaging agent or an amine-ketone-based antiaging agent. Can be further improved.

Further, in the multilayer rubber hose according to the fourth aspect, since the electrochemically degradable rubber hose composition according to the first aspect is lined, the hose can withstand use for a long period of time even under the condition of using an electrolyte solution. The unit price can be reduced.

In the multi-layer rubber hose according to the fifth aspect, the layers other than the innermost layer of the multi-layer rubber hose include ethylene-propylene copolymer rubber as a base material, carbon black, a softener, zinc oxide, and stearic acid. By having a rubber hose composition to which a filler such as a vulcanization accelerator and a vulcanizing agent is added, a base material having the same quality as the inner layer portion lined with the electrochemically degradable rubber hose composition can be used, and the bonding property can be improved. A better and cheaper rubber hose can be manufactured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a three-layer rubber hose according to an embodiment of the present invention.

FIG. 2 is an explanatory side view showing a test apparatus in a simple deterioration test method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rubber hose 2 Inner layer part 3 Reinforcement layer part 4 Outer layer part 12 Metal plug 13 Tightening tool 14 DC power supply 15 Thermostat

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 9/04 F16L 11/04 F16L 11/04 B60K 15/02 (72) Inventor Tetsuyoshi Kuroda Fujisawa, Kanagawa 48 Ishiburazawa, Tokyo F-term in Tokyo Rubber Works 3D038 CA09 CA22 CC13 3H111 AA02 BA12 BA31 BA32 BA34 CB04 CB11 CB14 CC02 DA26 DB19 DB20 4J002 BB151 DA036 DE100 DE237 EF050 EN078 EN098 FB237 FD016 FD017 FD017 FD020

Claims (5)

[Claims] 1. An ethylene-propylene copolymer rubber as a base material, 100 parts by weight of carbon black
100-200 parts by weight, surface-treated calcium carbonate 10-100
1. An electrochemically degradable rubber hose composition comprising 0.5 parts by weight of an antioxidant and 0.5 to 5 parts by weight of an antioxidant. 2. The electrochemically degradable rubber hose composition according to claim 1, wherein said surface-treated calcium carbonate is a resin acid-treated calcium carbonate and / or a fatty acid surface-treated calcium carbonate. 3. The rubber hose composition according to claim 1, wherein the antioxidant is an amine antioxidant or an amine-ketone antioxidant. 4. A multilayer rubber hose, which is lined with the electrochemically degradable rubber hose composition according to claim 1. 5. A layer other than the innermost layer of the multilayer rubber hose includes an ethylene-propylene copolymer rubber as a base material, carbon black, a softener, zinc oxide, stearic acid, a vulcanization accelerator, a vulcanizing agent. The multilayer rubber hose according to claim 4, further comprising a rubber hose composition to which a filler such as (1) is added.