JP3011289B2 - Apparatus and method for testing oil resistance of rubber material to deterioration by pressurized oxygen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for testing oil resistance of rubber materials to deterioration by pressurized oxygen, and more particularly to a rubber capable of evaluating deterioration of a material by immersing only one surface of the material. The present invention relates to an apparatus for testing a material for resistance to deterioration by pressurized oxygen and a test method using the apparatus.

[0002]

2. Description of the Related Art As a conventional method for testing a rubber material for deterioration oil resistance, a method according to JIS K6301 is applied. That is, the conventional test method is performed by simply immersing a test piece in oil and examining the effect after a lapse of a predetermined time. However, the test method in which the test piece is simply immersed was poor in efficient reproducibility in accordance with actual conditions. Therefore, a test method has been proposed in which oxygen is blown into oil to forcibly deteriorate the oil, or a metal piece is used as a kind of deterioration accelerating catalyst to examine the influence of the oil on the rubber material. For example, Japanese Patent Publication No. 1-20381 discloses that a test piece immersed in oil and the same oil is placed in a container maintained at a predetermined temperature, and the oil is further blown to supply the test piece to deteriorate the oil. A test method for examining the effect of oil on oil is disclosed.

[Problems to be solved by the invention]

[0003] However, in the above test method, although the reproducibility of the crack is higher than that of the conventional test method and the change over time can be reproduced in a short time, there is a difference between the actual use conditions and the test method, The reproducibility is not satisfactory. In other words, rubber hoses and the like used in actual automobiles and the like only contact oil on the inner surface,
Usually, at least some internal pressure is applied.

For example, when a tensile test is performed to evaluate the deterioration of a rubber material, according to the test method in which all of the test pieces are immersed in degraded oil as described above, the test pieces swell and soften. In fact, the longer the time of contact with the oil, the harder it will be. In addition, deterioration when a local defect such as a pinhole occurs was not able to be evaluated by the test method in which the entire test piece was immersed in oil as described above.

[0005] As described above, in the conventional known test method,
Eventually, all of the test pieces were immersed in oil, and one side did not come into contact with air, so there was a large difference from actual use conditions. Therefore, the deterioration phenomenon due to the hardening, softening and cracking of the rubber material that occurs at the oil contact site can be accurately performed.
In addition, there is a problem that the reproducibility is inferior to the actual efficiency.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and in addition to forcibly deteriorating the oil, the degradation phenomenon of the rubber material is put to practical use by bringing only one surface of the rubber material into contact under a constant pressure. It is an object of the present invention to provide an apparatus for testing a rubber material for resistance to deterioration by pressurized oxygen and a test method using the apparatus, which can be reproduced under almost the same conditions as those described above and can be evaluated accurately and efficiently.

[0007]

The present invention has the following configuration to achieve the above object. That is, the test apparatus according to the present invention was formed by a pressure-resistant container for containing oil, and a jacket provided with a gap between the pressure-resistant container and the pressure-resistant container. A test piece fixing opening is provided in a part of the test cylinder,
A fixed plate having a large number of through-holes and a fixed lid having a central portion opened are provided in the opening portion so that only one surface of the test piece comes into contact with oil,
Further, an oxygen supply pipe is attached to the pressure-resistant container, and a pipe for circulating a temperature control medium in the gap is attached to the jacket. And
As a test method using the above-described apparatus, the test piece fixing opening provided in the test cylinder is fixed so that only one side of the test piece is in contact with oil, and the oil inside the cylinder is maintained at a constant pressure and temperature. It is characterized in that the influence of the degraded oil on the test piece is examined by adjusting.

[0008]

The oil in the cylinder is kept constant at a predetermined pressure while the oil in the cylinder is kept at a predetermined temperature by installing a pipe for circulating a temperature adjusting medium through an oxygen supply pipe attached to the test cylinder.
In addition, since the test piece is fixed by a fixing plate having a large number of through holes and a fixing lid having an open central portion, only one surface comes into contact with oil and the other surface comes into contact with air.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus for testing a rubber material for deterioration resistance to oil under pressure, which embodies the present invention, will be described. The test cylinder 10 is formed in a double structure in which a space 13 is provided outside a pressure-resistant container 11 having a structure capable of sufficiently withstanding pressure and covered with a jacket 15. An oxygen supply pipe 17 is mounted on the upper surface of the test cylinder 10, and a fixing plate 20 for fixing a test piece 19 and a jacket 15 are mounted on the lower surface.
There is provided a fixed lid 21 which is screwed into a lower part of. Further, a pipe 23 and a pipe 25 communicating with the gap 13 are attached to the test cylinder 10.

More specifically, the pressure-resistant container 11 is a container made of, for example, stainless steel and has an open bottom surface, which is an opening 22 for fixing a test piece. The oxygen supply pipe 17 is provided with a pressure regulating valve 29 for adjusting the oxygen supplied from the oxygen cylinder 27, a pressure gauge 30, and a quick coupler 31. The fixing plate 20 is provided with a large number of through-holes.
The outer side is formed so as to be in contact with oil while the outer side is in contact with air. Therefore, it is preferable that the entire area of the through hole of the fixing plate 20 be as large as possible within the range of the pressure resistance so that the outside of the test piece 19 is brought into contact with the air as much as possible. The fixed lid 21 has an opening at the center, and the jacket 1
A screw is engraved so as to be screwed with the lower part of 5. As described above, a large number of through holes are formed in the fixing plate 20, and the fixing cover 2 is formed.
Since the center portion of the test piece 19 is opened, the inside of the test piece 19 comes into contact with oil and the outside comes into contact with air, so that the test can be performed under practical conditions. The ends of the pipes 23 and 25 are located below a thermostat 33 storing a temperature control medium 34 such as hot water or heating oil, and the temperature control medium is provided by a circulation pump 35 provided in the pipe 23. 34 is sent into the gap 13, discharged from the pipe 25, and circulated at a constant speed. Therefore, the pressure vessel 1
1 is supplied with pressurized oxygen via a quick coupler 31 so that the internal pressure can be kept constant, and the temperature inside the jacket 15, that is, the pressure vessel 11, is constantly adjusted by the circulating temperature adjusting medium 34. ing.

In order to use the test apparatus according to the above configuration,
The test piece 19 is fixed to the test piece fixing opening 22 of the pressure-resistant container 11. The test piece 19 is held down by the fixing plate 20 with the surface in contact with the oil inside, and the test piece 19 and the fixing plate 20 are fixed.
The fixing cover 21 is screwed into the lower portion of the jacket 15 and fixed. Next, after storing a required amount of oil in the pressure vessel 11, pressurized oxygen is supplied from the oxygen cylinder 27 to keep the internal pressure constant. Further, the temperature adjusting medium 34 stored in the thermostat 33 is circulated by the circulation pump 35 to the gap 1.
3, the pressure vessel 11 is adjusted to a constant temperature.
In this way, by forcibly oxidizing and degrading the oil under a certain pressure and bringing the oil into contact with one surface of the test piece 19, it is possible to evaluate the effect after a predetermined time has passed under conditions close to actual use. Can be.

Next, a test method of the present invention using the above apparatus will be described. The test cylinder 10 has a stainless steel pressure-resistant container 11 having an inner diameter of 60 mm and a height of 230 mm, an inner diameter of 100 mm.
A rubber sheet having a thickness of 2 mm and a diameter of 65 mm was fixed to the bottom opening 22 as a test piece 19a by covering with a jacket 15 having a height of 250 mm. The test piece 19a is a laminate of a fluororubber 37 and a nitrile-butadiene rubber 39. A pinhole 40 having a diameter of 5 mm is formed at the center of the fluororubber 37. Deterioration of the butadiene rubber 39 was evaluated.

After fixing the test piece 19a with the fixing plate 20 and the fixing lid 21, 200 ml of fuel oil (regular gasoline) was put into the pressure-resistant container 11, and oxygen was pressurized to 5 kgf / cm ² . Further, hot water of 80 ° C. was circulated as a temperature adjusting medium in the gap 13 in the jacket 15. As described above, after a predetermined time has elapsed (48 hours in this embodiment), the test cylinder 1 is inspected in order to examine a temporal change with respect to the deteriorated oil when one side comes into contact with the fuel oil while forcibly deteriorating the fuel oil.
0, and the Wallace hardness was measured.

FIG. 3 shows the measurement results. FIG. 3 is a line graph of the measurement result of the Wallace hardness around the pinhole 40. The horizontal axis represents the distance from the pinhole 40, and the vertical axis represents the Wallace hardness. In a conventional test method in which the entire test piece is immersed in oil, the layer not in contact with oil, that is, the nitrile-butadiene rubber 39 swells and softens, or elutes, making it impossible to measure Wallace hardness. However, it is shown that the test method according to the present invention can reproduce the local deterioration state (hardening deterioration) of the material and the deterioration state (hardening deterioration) of the peripheral portion thereof. From this, it can be seen that since only one side is in contact with the pressurized oxygen, the reproducibility of the curing phenomenon is high in accuracy and can be efficiently reproduced in a short time. In particular, the reproducibility of cracks can be achieved for the first time by the present invention.

The present invention is not limited to the above-described embodiment, and the test apparatus may have a configuration in which a side surface of the test cylinder 10 is opened to provide a test piece fixing opening.
In addition, gear oil and other lubricating oils can be used as the oil, and it goes without saying that the amount of pressurized oxygen, the temperature of the temperature adjusting medium, and the like are changed depending on the test conditions.

[0016]

According to the present invention, the following effects can be obtained. The test apparatus according to the present invention can forcibly degrade the oil by supplying the pressurized oxygen, adjust the oil temperature, and provide an opening for fixing the test piece, so that only one side of the test piece comes into contact with the oil. Can be done.
Accordingly, highly accurate reproducibility under conditions close to actual conditions can be obtained. Further, according to the test method of the present invention, pressurized oxygen is sealed in a container maintained at a predetermined temperature, and only one surface of the rubber material is brought into contact with oil that has been forcibly oxidized and degraded by pressurized oxygen, and the deteriorated oil is used. By evaluating the effect, the deterioration phenomenon due to hardening, softening and cracking under conditions close to actual use,
It can be reproduced accurately and efficiently in a short time.

[Brief description of the drawings]

FIG. 1 is a partial schematic cross-sectional explanatory view showing a test apparatus of the present invention.

FIG. 2 is an explanatory sectional view showing a method of fixing a test piece to a test cylinder.

FIG. 3 is a graph showing Wallace hardness around a pinhole.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Test cylinder 11 Pressure vessel 13 Void 15 Jacket 17 Oxygen supply pipe 19 Test piece 20 Fixing plate 21 Fixed lid 22 Test piece fixing opening 23 Piping 25 Piping 27 Oxygen cylinder 29 Pressure regulator 30 Pressure gauge 31 Quick coupler 33 Thermostat 35 Circulating pump 37 Fluorine rubber 39 Nitrile / butadiene rubber 40 Pinhole

Claims (2)

(57) [Claims] An opening for fixing a test piece is provided in a part of a test cylinder formed by a pressure-resistant container for containing oil and a jacket provided with a gap between the pressure-resistant container and the test container. A fixing plate having a large number of through holes for bringing only one side of the piece into contact with oil and a fixing lid having an open central portion are provided.Furthermore, an oxygen supply pipe is attached to the pressure-resistant container, and the jacket has a temperature inside the gap. An apparatus for testing a rubber material for resistance to deterioration by pressurized oxygen, wherein a pipe for circulating an adjusting medium is attached. 2. A test piece fixing opening provided in a test cylinder is fixed so that only one side of the test piece is in contact with oil,
A method for testing the resistance of a rubber material to degraded oil by pressurized oxygen, wherein the oil inside the cylinder is adjusted to a constant pressure and temperature to examine the influence of the degraded oil on the test piece.