â˜† The difference between UV UV aging test box for paint and plastic and aging test box for xenon lamp. Paints, plastics and other organic materials may be exposed to natural climatic conditions and light radiation for a period of time, such as loss of light, fading, yellowing, flaking, cracking, loss of tensile strength and loss of the entire layer. Even indoor light or sunlight through the window glass can cause damage to substances such as pigments or dyes. Therefore, for outdoor coatings, such as architectural exterior coatings and automotive coatings, weather resistance and light resistance are the most important testing items. Although everyone agrees that the weatherability and lightfastness of paints are important, they have their own opinions on what is the best test method for them. There are also many methods for evaluating the weather resistance and light resistance of paints at home and abroad. Generally, there are methods for artificially accelerating weather aging tests such as natural weathering test, xenon arc lamp irradiation, carbon arc lamp irradiation, and ultraviolet lamp irradiation. This article will explore how to choose the right test method.
Natural weather aging test The natural climatic aging test method is widely used at home and abroad. The main reason is that the natural climatic aging experiment results are more realistic, the cost is lower and the operation is simple and convenient. Although we can conduct natural weathering tests anywhere, the internationally recognized test site is Florida in the United States because of its sunny sunshine.
However, the shortcoming of the natural climatic aging test is that the test takes a long time, and the tester may not have such a long time waiting for the test result of a product. In addition, even in Florida, the climate cannot be exactly the same year after year, so the reproducibility of the test results is not satisfactory.
Xenon arc radiation test â˜† Xenon arc radiation test is considered to be the best simulation of the full solar spectrum because it produces ultraviolet light, visible light and infrared light. Because of this, it is considered the most widely used method at home and abroad. This method is described in detail in GB/T 1865-1997 (equivalent to IS 0113411: 1994). However, this method also has its limitations, namely the stability of the xenon arc lamp source and the resulting complexity of the test system. Xenon arc lamps must be filtered to reduce unwanted radiation. A variety of filter glass types are available to achieve different irradiance distributions. Which glass is chosen depends on the type of material being tested and its end use. Changing the filter glass can change the type of short-wavelength ultraviolet light that is transmitted, thereby changing the speed and type of material damage. There are three types of filtration commonly used: daylight, glazing, and extended ultraviolet light types (Methods 1 and 2 mentioned in GB/T1865-1997 correspond to the first two types).
â˜† Typical xenon arc radiation is equipped with an irradiance control system. The irradiance control system is important in the xenon arc radiation test because the inherent stability of the spectrum of the xenon arc lamp source is worse than that of the fluorescent ultraviolet lamp. Some people in foreign countries have examined the difference between a new neon arc lamp and a spectrum of old xenon arc lamps that have been used for 1000 hours. It was found that the spectral energy distribution not only changed significantly with the long wavelength range of the light source with the use of the lamp, but also changed significantly in the short wavelength range. The reason for this change is the aging of the xenon arc lamp, which is its intrinsic property.
â˜† A variety of remedies are also available for this change. For example, increase the frequency of lamp replacement to reduce the effects of light aging. Or the sensor can be used to control the irradiance. Despite the variation in spectral energy distribution due to lamp aging, Xenon arc lamps are still a reliable and practical source of light for weathering and sunlight exposure tests.
â˜† Most Xenon arc radiation test uses water spray and / or temperature automatic control system (the surface water spray) proposed by GB/T1865-1997 when simulating the wetting conditions. The limitation of the water spray method is that when the relatively low temperature water is sprayed onto the relatively high temperature test plate, the test plate will cool down, which will slow down the process of material damage.
â˜† In the xenon arc radiation test, high purity water is required to prevent deposits on the surface of the test plate. Therefore, the operating cost is high.
UV Lamp Irradiation Test â˜† For different exposure applications, there are different types of lamps with different spectra to choose from. The UVA-340 lamp is a good model for simulating sunlight in the main short-wavelength UV spectrum. The spectral energy distribution (SPD) of the UVA-340 lamp is similar to the spectrum extracted from 360 nm in the solar spectrum. The UV-B type lamp is also a commonly used accelerated artificial weathering test lamp. It destroys materials faster than UV-A lamps, but its shorter wavelength energy output than 360 nm can deviate from actual test results for many materials.
â˜† UV aging test of ultraviolet aging test chamber uses fluorescent ultraviolet light to simulate the destructive effect of sunlight on durable materials. This is different from the above-mentioned xenon arc lamp. The fluorescent UV lamp is similar in electrical principle to the ordinary illumination cold fluorescent lamp, but can generate more ultraviolet light than visible light or infrared light.
â˜† Irradiance (light intensity) control is necessary to obtain accurate and reproducible results. Most UV aging test devices are equipped with an irradiance control system. These precise irradiance control systems allow the user to select an irradiance metric when testing. Through the feedback control system, the irradiance can be continuously and automatically monitored and accurately controlled. The control system automatically compensates for insufficient illumination due to aging of the lamp or other causes by adjusting the power of the lamp. â˜† Fluorescent UV lamps simplify irradiance control due to their inherent spectral stability. All sources of light will age over time. But fluorescent lamps, unlike other types of lamps, do not change their spectral energy distribution over time. This feature enhances the reproducibility of the test results and is therefore a major advantage.
â˜† Some tests have shown that there is no significant difference in the output power of the aging control system equipped with irradiance control when the lamp used for 2 hours and the lamp using 5600h are used. The irradiance control device can maintain the constant light intensity. . In addition, their spectral energy distribution does not change, which is very different from the xenon arc lamp.
â˜† One of the main advantages of using the violet lamp aging test is that it can simulate the damage of the material in a more realistic outdoor humid environment. When the material is placed outdoors, it is estimated that it is frequently subjected to moisture for at least 12 hours per day. Because this moisturization is mostly manifested in the form of condensation, a special condensation principle is used in the accelerated artificial weathering test to mimic outdoor humidity.
â˜† During such a condensation cycle, the water tank at the bottom of the test chamber is heated to generate steam. The hot steam maintains the environment of the test chamber at 100% relative humidity at high temperatures. When designing the test box, the test plate should actually constitute the side wall of the test box. The back side of the test panel is exposed to room temperature at room temperature. The cooling effect of the indoor air reduces the temperature of the surface of the test panel to a few degrees below the steam temperature. These degrees of temperature difference allow the water to continuously drop to the surface being tested during the condensation cycle.
â˜† The condensate thus produced is a stable, pure distilled water. This water can improve the reproducibility of experimental results, eliminate water deposit contamination problems and simplify the installation and operation of test equipment. Because the material is generally wet for a long time outside the room, a typical circulating condensing system requires a minimum of 4 hours of testing time. The aging process of the ultraviolet aging test chamber of Dongguan Haoen Testing Instrument Co., Ltd. is carried out under heating conditions (50 Â° C), which will greatly accelerate the destruction rate of moisture on the material. Condensation cycles under prolonged, heated conditions are more effective in reproducing moisture-damaging materials than other methods such as water spray, dipping, and other high-humidity environments.
In addition, even in the natural weather aging test, there is an accelerated method, which is to install the test sample in a sample rack that can rotate with the sun to rise and fall, so that the sample remains in direct sunlight for most of the time. To obtain accelerated test results. Before the 1980s, carbon arc lamps or direct UV lamps were used for parallel testing, which also shortened the inspection cycle. Which test method is the best? There is no simple answer. Which method you choose depends on the material to be tested, the final application of the material, the mode of damage to the material being concerned, and financial factors. Although the national standard regulations and the current aging resistance test method in China are Xenon arc radiation, the Xenon arc radiation and UV aging tests abroad are widely used test methods. These two methods are based on completely different principles. The xenon lamp illumination chamber replicates all of the solar spectrum, including ultraviolet, visible and infrared light, with the aim of simulating sunlight. The UV aging test does not attempt to imitate the sun's rays, but only mimics the damage effect of sunlight. It is based on the principle that durable materials exposed to the outside for a long time are most damaged by aging caused by short-wave ultraviolet light.
to sum up:
1. We first introduce the simulation environment of the xenon lamp aging test chamber:
(1) Xenon lamp aging is mainly to simulate the full sunlight spectrum.
(2) The xenon lamp test chamber uses a xenon arc lamp that can simulate the full sunlight spectrum to reproduce destructive light waves in different environments, and can provide corresponding environmental simulation and acceleration tests for scientific research, product development and quality control.
The xenon lamp aging test chamber can be used to select new materials, change existing materials, or evaluate changes in durability after material composition changes. It can simulate the changes in materials exposed to sunlight under different environmental conditions. The aging test is carried out by exposing the material sample to the illumination and heat radiation of the xenon arc lamp to evaluate the light and weather resistance of some materials under the action of a high temperature light source. It is mainly used in automobiles, paints, rubber, plastics, pigments, and adhesives. Agents, fabrics, etc. 2. Secondly, we should introduce the environment simulated by the ultraviolet aging test chamber. (1) The ultraviolet aging test equipment mainly simulates the ultraviolet light in sunlight.
(2) The ultraviolet aging test chamber uses a fluorescent ultraviolet lamp as a light source to simulate the weathering resistance of the material by simulating ultraviolet radiation and condensation in natural sunlight to obtain the weather resistance of the material.
Dongguan Qingsheng Test Equipment Co., Ltd. UV test chamber is used for non-metallic materials, organic materials (such as: paints, paints, rubber, plastics and their products), under the climatic conditions such as sunlight, humidity, temperature, condensation and so on. Inspect the extent of aging of products and materials. Get discoloration, fading, etc. in a short time.
Dongguan Qingsheng Test Equipment Co., Ltd. after-sales service commitment:
1. One year warranty, lifetime service; 2. Free installation, commissioning and training at the buyer's site; 3. After receiving the equipment, the company will arrive at the on-site service within 8 hours in Guangdong Province; within 2 working days outside Guangdong Province, arrive at the scene. The user solves the problem. 4. Warranty period: If it is a normal operation, causing damage to a certain component, the supplier can replace a component for free. If serious quality problems occur within 3 months, our company can unconditionally change the new model of the same model. 5. After the warranty period: If it is a normal operation, a part or part is damaged and needs to be replaced, and only the cost is charged. 6. Can provide comprehensive technical training, provide timely and perfect after-sales service for equipment maintenance, spare parts supply and other aspects.
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