JPH0128897B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for conducting weathering tests under accelerated conditions. Generally, organic and inorganic materials deteriorate due to heat, light, oxygen in the air, water, etc. It goes without saying that the best way to check the weather resistance of materials used outdoors is to expose them to the outdoors over a long period of time.
However, it has the disadvantage of requiring very long-term exposure. In order to eliminate the above-mentioned drawbacks and enable weather resistance tests to be carried out within a shortened period of time, weatherometers equipped with an ultraviolet irradiation device and a sprayer have recently been used. The above Weatherometer (1) can irradiate ultraviolet rays of a certain intensity, (2) can adjust the spray time and intensity, (3) can automatically adjust the temperature inside the testing machine, etc. On the other hand, it has the disadvantage that its mechanical properties, changes in appearance, etc. do not match the results of outdoor exposure tests. Therefore, the object of the present invention is to conduct a short-term weather test under accelerated conditions that provides results that closely match the results of an outdoor exposure test in terms of mechanical strength, changes in appearance, etc., without sacrificing the advantages of the weatherometer. The purpose is to provide a method that can be used in the meantime. That is, the gist of the present invention is that when performing a weather resistance test using a weather resistance tester that is equipped with at least an ultraviolet irradiation device, a spray device, and a sample holding device in a container, the oxygen partial pressure in the atmosphere is determined by A weather resistance test method characterized by keeping the relative humidity of the atmosphere at 40% or less during ultraviolet irradiation. The container used in the present invention is equipped with at least an ultraviolet irradiation device, a spray device, and a sample holding device. As the above-mentioned ultraviolet irradiation device, spray device, sample holding device, etc., devices similar to those provided in a weather resistance tester generally used as a weatherometer can be used. The equipment includes a temperature control device, a sample mounting device with a rotating device, an air outlet, an exhaust port,
A viewing window or the like may be provided. In the present invention, the weather resistance test is carried out by making the oxygen partial pressure in the atmosphere in the container higher than the oxygen partial pressure in the atmosphere. Any known method may be adopted, such as a method in which the oxygen partial pressure is made higher than the oxygen partial pressure in the atmosphere by feeding air into the container using a compression pump or the like to pressurize the atmosphere, or in the air atmosphere in the container. There are methods such as injecting oxygen or a mixed gas containing oxygen into the air to replace nitrogen in the air with oxygen, thereby increasing the proportion of oxygen in the atmosphere and making the partial pressure of oxygen higher than the partial pressure of oxygen in the atmosphere. Adopted. In the present invention, the oxygen partial pressure in the atmosphere need only be made higher than the oxygen partial pressure in the atmosphere.
Further, the pressure may be determined as appropriate depending on the amount of ultraviolet irradiation, the amount of hot water (or water) sprayed, etc., but it is generally preferable to set the pressure to 0.8 to 2.0 atm. When conducting an accelerated weathering test using the test method of the present invention, it is preferable to increase the oxygen partial pressure of the atmosphere according to the intensity of the amount of ultraviolet rays irradiated with respect to the amount of sunlight irradiated under natural conditions. Similarly, by increasing the ratio of the oxygen partial pressure inside the container to the oxygen partial pressure in the atmosphere according to the intensity of the UV irradiation, that is, the ratio of the amount of UV irradiation inside the container to the amount of irradiation under natural conditions, The deterioration and the deterioration caused by the atmosphere such as oxygen progress in a well-balanced manner, and the sample is not subject to any negative effects such as those that are strongly affected by ultraviolet rays, similar to what would happen over a long period of time in a natural environment. Weather resistance test results can be obtained in a short period of time. Note that if the light source of the ultraviolet irradiation device is brought too close to the surface of the sample, which is the object to be irradiated, only the deterioration effect of ultraviolet irradiation will become stronger, and the effects of the atmosphere such as oxygen and moisture will be weakened, making it difficult to obtain the test results aimed at by the present invention. Therefore, in the present invention, it is preferable to keep the distance from the light source to the sample at 10 cm or more. However, in accelerated weathering tests,
Generally, spraying water onto a sample and irradiating it with ultraviolet rays are carried out periodically, but since a closed container is used in the method of the present invention, the humidity in the atmosphere is extremely high after spraying water. Become. Under these circumstances, the acceleration of deterioration due to UV irradiation under elevated oxygen partial pressure is inhibited, the degree of progress of deterioration is reduced, and UV irradiation is carried out in an atmosphere with low humidity, which improves the deterioration. The present inventors have discovered that a good deterioration rate can be obtained, and therefore, in the present invention, in order to obtain a good deterioration rate, the relative humidity of the atmosphere during ultraviolet irradiation is set to 40% or less. . The relative humidity can be easily adjusted within the above range by spraying water and then replacing the air in the container with dry air. Next, the method of the present invention will be explained with reference to the drawings. FIG. 1 is a sectional view showing an example of a weather resistance test apparatus used in the present invention. In the figure, 1 is a container, and the container 1 can be pressurized. 2 is a peephole. Reference numeral 3 denotes a light source lamp (power source not shown) which is made of a pressure-resistant structure with a quartz protection tube 4. As the light source lamp, mercury lamps, xenon lamps, carbon arcs, ultraviolet carbon arcs, etc., which have been conventionally used in weatherometers, are used, but mercury lamps and xenon lamps are preferable because the structure can be made smaller. Reference numeral 5 denotes a sample holding device, which is rotated by a rotation motor 6 provided with a transmission device 7. The sample holder 5 and the light source lamp 3 are arranged so that the distance between the sample attached to the sample holder 5 and the light source lamp 3 is maintained at a distance of 10 cm or more. 8 is a sprayer installed so that water, hot water, etc. can be sprayed onto the sample. 9 is an air outlet connected to a compressor (not shown); 10
is a drain port provided with a pressure regulating valve 11, and by adjusting the operating pressure of the compressor and the pressure regulating valve 11, the pressure inside the device can be adjusted. In the weather resistance test according to the present invention, while rotating the sample holding device 5 to which the sample is attached, the sample is sprayed with water by the spray 8 and irradiated with ultraviolet light from the light source lamp 3 to increase the oxygen partial pressure. In the above-mentioned ultraviolet irradiation, the humidity increased by spraying water with the spray 8 is forced into the drain port 10 while the dry air is forced into the air outlet 9.
The above-mentioned irradiation is carried out in such a manner that the relative humidity of the atmosphere is 40% or less by removing water and air with high humidity from the atmosphere. The weather resistance test method of the present invention is as described above, and in particular, when conducting the weather resistance test, the oxygen partial pressure of the atmosphere is made higher than the oxygen partial pressure of the atmosphere, and the relative humidity of the atmosphere during ultraviolet irradiation is adjusted.
Since the temperature is kept below 40%, deterioration due to ultraviolet irradiation and deterioration due to atmosphere such as oxygen and moisture proceed at a faster rate in a well-balanced manner than in accelerated weathering tests conducted with conventional weatherometers. Therefore, it is possible to obtain accelerated weathering test results that closely match the outdoor exposure test results in terms of changes in mechanical strength, appearance, etc. Examples of the present invention will be described below. Example 1 A galvanized steel plate sample with a width of 7 cm, a length of 14 cm, and a thickness of 1 mm was attached to the sample holder of the weather resistance test device shown in Figure 1, and the amount of ultraviolet light received was measured.
Set the distance to 3.45 cal/cm ² hr, introduce air from the air outlet to maintain the internal pressure at 5 atm, and reduce the temperature.
Adjustments were made to maintain the temperature at 50°C. Then, the spray sprays approximately 160 sprays of hot water at approximately 55℃ in 120 minutes, followed by ultraviolet irradiation.
The test was conducted in a 20 hour cycle. However,
In this test, the air inside the container was replaced with dry air after spraying, and the relative humidity during irradiation was maintained at approximately 30%. The results were as shown in Table 1. For comparison, we also include the results of an outdoor bacterium test on the same sample as above.

[Table] Example 2 100 parts of polyester resin (parts by weight, same below),
A mixture of 10 parts of polyester, 30 parts of styrene monomer, 30 parts of glass fiber, and 5 parts of magnesium oxide with a catalyst added was molded under pressure at 150°C for 10 minutes to form a plate with a thickness of 1 mm. Using this plate as a sample, a pressure test was conducted for a specific time shown in Table 2 under the same conditions as in Example 1, and the glossiness (measured with a surface glossmeter) and Charpy impact value were measured. The results were as shown in Table 2. In addition, the results of an outdoor bacterium test conducted on the same sample as above are also listed.

【table】 [Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a weather resistance test apparatus used in the present invention. 1... Container, 2... Peephole, 3... Light source lamp, 4... Quartz protection tube, 5... Sample holding device, 6
... Rotation motor, 7 ... Transmission tool, 8 ... Spray, 9 ... Ventilation port, 10 ... Drain port, 11 ...
Pressure control valve.

Claims (1)

[Scope of Claims] 1. When conducting a weather resistance test using a weather resistance tester that is equipped with at least an ultraviolet irradiation device, a spray device, and a sample holding device in a container, the oxygen partial pressure of the atmosphere is determined as the oxygen partial pressure in the atmosphere. A weather resistance test method characterized by keeping the relative humidity of the atmosphere at 40% or less during ultraviolet irradiation as well as keeping the relative humidity higher than the partial pressure. 2. The test method according to claim 1, wherein the oxygen partial pressure is made higher than the oxygen partial pressure in the atmosphere by pressurizing. 3. The test method according to claim 1, wherein the oxygen partial pressure is made higher than the oxygen partial pressure in the atmosphere by replacing nitrogen in the atmosphere with oxygen. 4. The test method according to claim 1, 2 or 3, wherein the oxygen partial pressure is 0.8 to 2.0 atm.