JPH0480336B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to an accelerated weathering test device for plastics, fibers, paints, etc. [Technical background of the invention and its problems] Conventionally, when measuring the weather resistance of plastic materials, etc., weather resistance testers according to JIS B7751 to 7754 have generally been used. These test machines usually use a light source such as a carbon arc lamp or a xenon arc lamp, and perform a weather resistance test by irradiating the sample with light from the light source. However, the ultraviolet irradiation intensity of the devices using the above-mentioned light sources used in these testers is generally about 6 mW per cm ² of the irradiated surface, and it is difficult to measure and measure the ultraviolet deterioration characteristics equivalent to one year of sunlight. It took several hundred hours or more to make the distinction. Moreover, the conventional method of testing all samples from each lot has been common, which poses the problem of being extremely inefficient as it takes a long time to measure and judge the results. Ta. In order to shorten the measurement time, it is conceivable to increase the intensity of ultraviolet irradiation, but in this case it has not been possible to realize an environment in which a correlation with natural irradiation can be obtained in a compact device. [Object of the invention] The present invention has been made in view of the above points, and
It is an object of the present invention to provide a compact weather resistance accelerated testing device for conducting conventional weather resistance tests in a short time while maintaining correlation. [Summary of the invention] The ultraviolet light source used in the present invention is
This is a discharge lamp system for ultraviolet irradiation disclosed in No. 197742, which has a water-cooled jacket around the outer periphery of a metal halide lamp arc tube, and a filter made of low-melting soft glass for transmitting ultraviolet rays is provided in the water of the water-cooled jacket. be. This discharge lamp system was developed for use in instantly drying and solidifying paints and synthetic resin materials by irradiating them with ultraviolet rays. In the apparatus according to the present invention, this discharge lamp system is placed in a closed room, a reflector is provided on the top, and a sample stage is placed below. Further, a means is provided for cooling the sample by blowing air onto the sample mounting table. With this configuration, strength is added to the surface of the sample.
The mounting table is positioned so that the sample is placed in a position where it is irradiated with ultraviolet rays of 50 mW/cm ² or more. Many experiments have shown that the apparatus of the present invention has a correlation with natural light in a time several tenths of that of conventional weather resistance test apparatuses. The present invention resides in the compactness of its construction as an accelerated weather resistance tester. The fact that such a compact configuration can be expected to have high accelerating performance while maintaining a correlation with natural light is a major advance in weatherability tester technology compared to the prior art. [Explanation of Experimental Examples] First, the ultraviolet irradiation conditions in the apparatus of the present invention will be explained. The sample was equipped with a high-pressure metal vapor discharge lamp and substantially 300~
A light source combined with a filter that transmits only ultraviolet rays in the 400 nm wavelength range emits ultraviolet rays at a rate of 50% per cm ² of the irradiated surface under conditions where the sample temperature is below 80°C.
Irradiate with an intensity of mW or more. The reason why the wavelength range of ultraviolet rays is set in the above range is that wavelengths below 300nm, more precisely 275nm or below, do not meet the test conditions stipulated by JIS, and on the other hand, wavelengths exceeding 400nm contain a large amount of visible light and infrared light. The reason for this is that it is necessary to avoid this, as this will increase the influence of heat on the sample. On the other hand, the higher the intensity of ultraviolet rays irradiated onto the sample, the better, but the limit in the apparatus of the present invention was about 80 to 200 mW per cm ² of the irradiated surface. The ultraviolet light source used in the device of the present invention is
This is a discharge lamp system disclosed in No. 197742. This lamp includes a so-called metal halide lamp in which halides of iron and tin are sealed together with an appropriate amount of mercury and rare gas inside a quartz glass arc tube with at least one pair of electrodes, and the emission spectrum when lit is shown in Figure 1. As shown in the figure, it has considerably large energy in the wavelength range of 300 to 400 nm. This metal halide lamp is not limited to one containing iron and tin halides, but may be one containing a metal halide mainly containing iron halide. Carbon arc lamps, which have traditionally been used in weather resistance testers, are lamps with energy peaks in the wavelength range of 300 to 400 nm, but these lamps emit a large amount of infrared radiation as well as ultraviolet radiation. CO while the lamp is on,
Because gases such as CO ₂ , NO, and NO ₂ are generated, the lamp itself must be equipped with a cooling and ventilation mechanism, as described in Japanese Utility Model Publication No. 16796/1983, and the lamp and the entire device must be equipped with a cooling and ventilation mechanism. However, the method is complicated, large-sized, and expensive, and cannot be applied to a device that further enhances acceleration performance. Even when using a metal halide lamp as described above, radiation of energy in a wavelength range other than 300 to 400 nm is unavoidable, so by combining an appropriate filter, the wavelength range to be irradiated can be effectively reduced to 300 to 400 nm.
It is necessary to narrow it down to. The best filter to use for this purpose is, for example, a weight ratio of 60
~65% _SiO2 , 15-20% Pb and 7-8%
Na, 7-8% K, 1% Co, 1% Ni
It is a filter made of low melting point soft glass. The ultraviolet transmission characteristics of this filter are as shown in FIG. 2, and by combining this filter with the metal halide lamp, ultraviolet rays of 300 to 400 nm can be obtained extremely efficiently. However, if the filter is simply installed around a metal halide lamp, the filter will be immediately damaged by the radiant heat from the lamp. Therefore, in practice, as shown in FIGS. 3a and 3b, the arc tube 1 is arranged at the center of the water-cooled jacket 2, and a filter 3 is placed between the inner tube 2-A and the outer tube 2-B of the water-cooled jacket 2. A light source with a structure mounted on it is used. That is, the discharge lamp system used in the present invention disclosed in JP-A-57-197742 consists of a metal halide lamp (metal discharge lamp), a filter, and a cooling jacket. In addition, in a weather resistance tester, a filter is combined with a lamp to test a specific wavelength range, for example 300 to 400n.
For example, controlling ultraviolet rays of
Publication No. 29675 and Utility Model Publication No. 54-29034, both of which show that the radiant energy of the lamp changes with the elapse of lamp lighting time and changes in current and voltage. Considering that the energy components of
The voltage applied to the lamp is controlled according to the change, and is completely different from the method of the present invention in which the light from the lamp is irradiated onto the sample through a filter. FIGS. 4a and 4b show an example of the testing machine of the present invention. In the figure, 4 is the testing machine main body, 4a is an ultraviolet irradiation chamber, and 4b is an accessory storage chamber. A lamp having a reflecting mirror 5 is mounted on the upper part of the ultraviolet irradiation chamber 4a, and a light source 6 is mounted inside the reflecting mirror 5. In the apparatus of the present invention, the reflecting mirror 5 reflects the light emitted upward from the discharge lamp system to the sample mounting table below, and is made of a metal plate such as aluminum or a metal-plated reflecting plate. Enough. A sample holder 7 is provided below the light source 6 and is vertically adjustable so that the distance between the light source 6 and the sample holder 7 can be adjusted. Moreover, it is installed so that it can be tilted and rotated freely. A blower 8 is configured to send cooling air onto the sample mounting table 7 . In addition to a lighting device and a stabilizing device for the light source 6, a pump and a cooler for the light source cooling liquid are stored inside the accessory storage chamber 4b. In such a test apparatus, for example, a metal halide lamp with a rated input of 1.5 kW is used as the light source, and the distance between the light source 6 and the sample mounting table 7 is 10 cm.
Sample mounting table 7 when light source 6 is lit at rated input
The intensity of the ultraviolet rays above is approximately 100 mW per cm ² . This is about 10 to 15 times the UV irradiation intensity of conventional weather resistance testers, and if the UV rays of the sample exposed to such strong UV rays tend to be the same as the UV rays of the sample exposed to natural light. If it is, it will be possible to determine the ultraviolet deterioration characteristics in about 1/10 to 1/15 of the time required when using a conventional weather resistance tester. The most important issue with the weather resistance tester intended to accelerate according to the present invention is whether the ultraviolet deterioration characteristics of the sample when irradiated with strong ultraviolet rays and the ultraviolet deterioration characteristics of the sample irradiated with natural light show the same tendency. That's it. This is because the weather resistance tester according to the present invention is meaningless unless it shows the same tendency. Therefore, as shown in the experimental examples below, samples made of various plastic materials were tested using the tester of the present invention and a conventional weather resistance tester, which is said to have a correlation with ultraviolet degradation caused by natural light. We investigated the trends and extent of this. The testing machine and test conditions used in each experimental example are as follows. (1) Testing machine of the present invention Model: Manufactured by Iwasaki Electric Co., Ltd. (structure shown in Figure 4 a and b) Conditions: Lamp used: Metal halide lamp
1.5kW (Energy distribution is shown in Figure 1) Irradiation wavelength: 300 to 400nm Ultraviolet irradiation intensity on sample surface: 100±5mW/cm ² Maximum temperature on sample surface: 65℃ or less (2) Conventional testing machine Model... WE-SUN-HC manufactured by Toyo Rika Kogyo Co., Ltd.
(Testing machine used for test method based on JIS A1415) Conditions: Lamp used: Carbon arc lamp
4kVA UV irradiation intensity on sample surface: 5mW/cm ² Black panel temperature: 63±3℃ Spray: 18 minutes/120 minutes Additionally, in this test, the tendency of UV deterioration was determined from the color difference and changes in physical properties of the sample subjected to the above testing machine. The gender and severity were investigated. Therefore, we will introduce the determination methods and test results of specific experimental examples for each color difference test and physical property test. In addition, in the following experimental examples, typical plastic materials were selected as samples and tests were conducted under the specific conditions described above, and the present invention is not limited by these experimental examples. It's not something you can do. (A) Color difference test Determine the total color difference before and after the test for the samples obtained at each time with the two testing machines mentioned above, plot this on a graph with time on the horizontal axis and color difference on the vertical axis, and compare the same color difference. The respective times were read, and the ratio of the times of the conventional tester and the tester of the present invention was determined, and the magnification of the UV deterioration accelerating property was determined. The total color difference is based on CIEL, the color system of the 1976 International Certification Committee.
ΔE (color difference) was determined from (I)a(I)b(I). In addition,
CR-100 manufactured by Minolta Camera Co., Ltd. is used as a color difference meter.
was used. Experimental example 1 Sample: Organotin-containing transparent rigid PVC sheet, thickness 0.4
mm (reference color: Y = 47.4x = 0.307y = 0.311) [Measured with a white sheet on the back (the same applies hereinafter)] Results: When using a conventional testing machine...as shown in Figure 5 a. When using the tester of the present invention...as shown in FIG. 5b. Comparison: As shown in Table 1 (average magnification 12.7)

[Table] Experimental example 2 Sample: ABS sheet (grade: Toray A-322, natural), thickness 2.0 mm (standard color: Y = 62.5x =
0.328y=0.342) Results: When using a conventional testing machine...as shown in Figure 6a. When using the testing machine of the present invention...as shown in FIG. 6b. Ratio: As shown in Table 2 (average ratio 15.4)

[Table] Experimental example 3 Sample: Acrylic modified PVC sheet (product name: Oopura AV sheet), thickness 3.0 mm (standard color: Y = 73.7x
= 0.320y = 0.319) Results: When using a conventional testing machine...as shown in Figure 7a. When using the testing machine of the present invention...as shown in FIG. 7b. Comparison: As shown in Table 3 (average magnification 14.3)

[Table] Experimental example 4 Sample: Polycarbonate (Product name: Oopura hollow sheet PD-600, thickness 6.0mm (Reference color: Y = 34.9x
= 0.314y = 0.317) Results: When using a conventional testing machine...as shown in Figure 8a. In the case of using the testing machine of the present invention...as shown in FIG. 8b. Comparison: As shown in Table 4 (average magnification 13.8)

[Table] Experimental example 5 Sample: Polyethylene sheet (grade: Mitsui Petrochemicals Hi-Zex 5000SF), thickness 0.5 mm (standard color: Y = 57.2x = 0.305y = 0.309) Results: When using a conventional testing machine...Figure 9 As shown in a. When using the testing machine of the present invention...as shown in FIG. 9b. Comparison: As shown in Table 5 (average magnification 10.3)

[Table] As is clear from the comparative data of Experimental Examples 1 to 5, with the tester according to the present invention, data on ultraviolet degradation of samples can always be obtained in a shorter time than when using the conventional weatherability tester. The magnification is approximately 10~
It was 20 times larger, and on average about 15 times larger. This almost agrees with the prediction calculated from the difference in the intensity of ultraviolet irradiation per 1 cm ² of the irradiated surface, and the ultraviolet deterioration characteristics of the sample when using the tester according to the present invention are the same as those when subjected to the conventional weather resistance tester. It was confirmed that the same trend was observed. The reason why there are differences in the acceleration of ultraviolet light deterioration depending on the type of plastic material is that the absorption characteristics of ultraviolet light differ depending on the molecular structure and initial hue of the plastic material. Furthermore, as ΔE increases, the magnification tends to increase, but this is because the tester according to the present invention does not use water, so the surface of the sample tends to be larger than when using a conventional weatherability tester. It is thought that there was less dirt on the surface and that UV deterioration was accelerated. (B) Physical property test (B-1) 180 degree bending test 30 mm in the center of a sample with a sample width of 10 mm and a length of 65 mm.
After irradiating the portion with ultraviolet rays using a conventional testing machine and a testing machine of the present invention, the degree of deterioration of the physical properties of the sample was examined by repeatedly bending it 180 degrees. Experimental example 6 Sample: Polypropylene sheet (grade: Tokuyama Soda RB-110) thickness 0.2 mm (standard color: Y = 65.5x
=0.312y=0.316) Results and comparison: As shown in Table 6.

[Table] (B-2) Tensile impact test A test was conducted based on ASTMD1822 using a universal impact tester manufactured by Toyo Seiki Seisakusho Co., Ltd., and the comparison between the conventional tester and the tester of the present invention was conducted in the same manner as the color difference test. The time ratio was determined and the acceleration of ultraviolet deterioration (magnification) was determined. Experimental Example 7 Sample: Acrylic modified PVC sheet (product name: Oopura AV Sheet), thickness 3.0mm Results: Using a conventional testing machine...as shown in Figure 10a. When using the tester of the present invention...as shown in FIG. 10b. Comparison: As shown in Table 7 (average magnification 7.8)

[Table] As is clear from the data of Experimental Examples 6 and 7, when the testing machine according to the present invention is used, the data on ultraviolet deterioration of the physical properties of the sample is also improved compared to when using the conventional weather resistance testing machine. can be obtained in an extremely short time. [Effects of the Invention] As is clear from the above experimental examples and test results, by using the tester according to the present invention, it is possible to reliably determine the tendency and degree of ultraviolet degradation characteristics of a sample in a very short time. The tester of the present invention has a simpler structure than conventional weatherability testers and does not impose a large economic burden.

[Brief explanation of drawings]

Figure 1 is a spectral energy distribution diagram of a metal halide lamp used as an ultraviolet light source used in the present invention, Figure 2 is a transmission characteristic diagram of a filter used in combination with the same metal halide lamp, and Figures 3a and b are diagrams of the metal halide lamp and filter, respectively. Front view and side view of the light source in combination with, Figure 4a,
b is a front view and a side view of the testing machine of the present invention, respectively, and Figs. 5 to 10 are comparison diagrams of the test results by the testing machine of the present invention and the test results by a conventional testing machine. [Description of symbols of main parts], 4a...Ultraviolet irradiation chamber, 5...Reflector, 7...Sample mounting table, 6...
light source.

Claims (1)

[Claims] 1. A metal vapor lamp tube in which a metal halide is sealed together with mercury or a rare gas, and the light surrounding the lamp tube and generated from the lamp tube is included in sunlight incident on the inner surface of the earth. A filter means for substantially removing wavelength components other than ultraviolet components and wavelengths other than 300 to 400 nm, a transparent inner tube (2-A) surrounding the lamp tube, and an outer tube (2-A) transparent to at least the ultraviolet components; 2-B) and means for flowing a cooling liquid into the gap between the inner tube and the outer tube, the filter means comprising a cooling liquid in the gap between the inner tube and the outer tube. a discharge lamp system consisting of a cooling jacket immersed therein (FIG. 3); and a sample placed therein to expose the sample to ultraviolet radiation emitted from the discharge lamp system and incident on the sample. Sample mounting means for placing the sample in a position such that the ultraviolet light intensity is 50 mW/cm ² or more; means for maintaining the temperature below 80°C; a metal or metal-plated reflector that reflects light emitted from the discharge lamp system in a direction other than the direction toward the sample placement means; and a weather resistance test characterized by comprising a closed chamber surrounding the discharge lamp system, the sample mounting means, and the reflecting plate to form a closed environment for testing the weather resistance of the sample. Device. 2. The weather resistance test device according to claim 1, wherein the filter means is made of low melting point glass. 3. The weather resistance test apparatus according to claim 1, wherein the sample mounting means includes means for adjusting the distance between the test and the lamp tube.