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    2. You are here:Home>News>Technical journal

      MEBON Instrument technical journal-first issue

      分類:Technical journal  發布日期:2017-01-10 02:49:53  瀏覽次數:2248  [返回]
      A discussion on the light source of the sun weather color fastness tester - first issue
      Release time: 2017-01-10
      Subject: A discussion on the light source of the sun climates
          Although the application because of like heat, moisture and mechanical changes will accelerate aging and affect the performance of the final material change, but exposure to life in the outdoor material is mainly restricted by the ultraviolet radiation of the sun, so I from the laboratory aging of various light sources used in the trial to begin my discussion.
      1. Closed carbon arc lamp
         This kind of lamp has been used for about 70 years. In 1918, it first used the fastness test of textiles to become the light source of AATCC (American Association of Textile Chemists and Colorists). Now many old codes still require it.
         The enclosed carbon arc lamp is composed by a team, which is sealed in a metal gas inspection board (metal gas check plate) airtight envelope and borosilicate glass ball formation, when the current is flowing in between, generating arc. Because the carbon electrode composition, decided it produced during the combustion of light quality, any changes to the element will change their spectral energy distribution (SPD), thus changing the test conditions.
         The SPD of a closed carbon arc lamp shows that its main energy is concentrated in 3 quite narrow wavebands. Relatively small energy is available at less than 345nm, and the polymer has the maximum absorption sensitivity in this section. But the spectral power distribution of the closed carbon arc lamp is quite different from that of natural sunlight. Carbon arc lamps do not have short wave ultraviolet radiation from natural sunlight, and there is no high intensity energy for sunlight between 400~800nm. Because of the large difference between the light and the sunlight, it is difficult to compare the aging of the natural climate and the correlation between the use of the laboratory aging of the carbon arc lamps.
      2. Fluorescent carbon arc lamp
         The solar carbon arc lamp, as well as the closed carbon arc lamp, is the light source used in the week aging test, which began in 1933. The arc in the three team of carbon arc lamp, around eight pieces of glass filter, which is mainly used in the paint industry, many specifications using the same light source.
         Because of the defects of enclosed carbon arc lamp, fluorescent carbon arc lamp carbon composition change, make it SPD is similar to the sunlight has significantly improved. However, the significant difference between 350nm and 50nm compared with the SPD of daylight still leads to a poor correlation.
      3. Fluorescent ultraviolet lamp
         In theory, the energy of short wave is the main. If it has little energy, it can lead to the aging of the material. Why not increase this energy significantly to achieve the effect of rapid test? Comparing the SPD and Florida SPD of FS-40 fluorescent lamp, we can see that the design standard of ultraviolet energy increased, not only the UV energy level increased, but also the spectral range increased to the UV energy in natural light. A sharp change in the energy distribution can accelerate damage to many products.
         The fluorescent device can cause unnatural damage due to the presence of no radiation energy in natural sunlight in the measurement of the earth's surface. In addition, besides the very narrow mercury spectral line, the fluorescent light source has no energy higher than 375nm, so that long wavelength UV energy sensitive materials may not change the exposure to natural sunlight.
         Because of these inherent defects, it is not only in the spectral distribution, but also in other factors that can not be controlled, thus the irregular results are obtained. Atlas companies generally do not consider the use of this light source. We believe that its main purpose is to be used as a UV screening device, limited to quality control applications.
      4. Xenon arc lamp
         The latest and best light source is the xenon arc lamp, which was first introduced in 50s as an air cooling system, followed by water cooling in 60s. This light source has a great impact on the use of sealed carbon arc lamp accelerated aging test equipment in the initial conceptual period of accelerated aging in the early century.
         From the mercury a tungsten filament lamp to the carbon arc lamp, as well as the current "unified world" long arc xenon lamp, its spectral curve can not conform to the solar spectrum. To this end, the manufacturers are modified by different characteristics of the filter in order to maximize the solar spectrum.
      5. Problems to be solved in the air cooled long arc xenon lamp
      (1). Measurement and control of light intensity
      The light energy of the tested material is too small to directly affect the decomposition rate of the dye, so the monitoring and control of the radiation energy is particularly important. At first, the sun color fastness instrument used in China's textile industry began with the XF L - I produced by the imitation of Japan's Shiga company. The machine in the last century, from 80 to 90s in order to solve the detection task of the lower end of the textile industry made distinctions won in battle, but due to technical performance of the machine has inherent deficiencies: pressure pump spray, high failure rate, large noise; hair pointer hygrometer low control precision (+ 10%RH), unresponsive to temperature control; inside the warehouse, plus the electrical principle design of the old, after 20 years is not much improved, so there is no other similar imported instruments form the slightest pressure. At present, the total energy compensation solar energy color fastness instrument has been introduced in China. It can be set arbitrarily in the range of illumination intensity 220~1100 W / m2 and automatically compensated. This can be measured in the radiation intensity under the known test time is given, so as to solve the problem in suspense for 20 years.
      (2). Measurement and control of humidity
      The process of discoloration of the sample includes the photothermal decomposition, water solubility and sublimation of the dye. When the humidity is significantly increased, most of the water soluble dye will strengthen the decomposition will be accelerated, so the instrument must have a sensitive, fast and reliable humidity measurement and compensation system, in order to ensure warehouse comprehensive precision humidity less than 5%RH, and trouble free continuous intermittent operation for more than 1 years.
      (3). Chamber temperature
      As the long xenon arc lamp produces a large amount of heat energy at the same time, the heat accumulation in the chamber is accumulated, and the temperature is gradually increased. The practice of domestic instruments is to increase the amount of ventilation. The result of this result is the instability of the state in the silo, which makes the air flow out of control. To this end, only the increase of the refrigeration system can effectively control the temperature in the chamber. The above only solved the precision of the instrument, and the key problem of the domestic textile instrument is the reliability of the instrument. The fault terminal is mostly concentrated on the electrical system, especially the devices related to the operation (such as panel keys, functional conversion, etc.).

      Reference
      1. Xu Haisong editing. Color information engineering [M]. Hangzhou: Zhejiang University press, 2005.
      2. Li Ruqin et al. Testing principles and instruments for fiber and textiles [M]. Beijing: China Textile University Press, 1995.
      3. Yan Haojing editor. Textile instrument [M]. Beijing: China finance and Economics Press, 1965.
      4. Their chroma. [M]. Beijing: Science Press, 1979.

      This week's recommendation: the sun weather test machine
      We have the following characteristics: the sun exposure test machine has the following characteristics:
      Feature 1: Xenon lamp light sources close to the sun. Can simulate the xenon arc lamp light spectrum reproduction under different environments the destructive wave, solarization climate test machine in comparison with this characteristic, can well simulate under different environmental conditions, the resulting changes in the materials under the light exposure, because the simulation experiment environment closer to the natural state, so the test results will be more accurate.
      Feature 2: accurate control and high degree of automation. Such a controlled solar climate test machine is very convenient to use, and requires less manual operation. It can guarantee the accuracy of detection with precise control, and complete the detection work intelligently with a higher degree of automation.
      Feature 3: intelligent operation display system. The solar climate tester with this characteristic can set parameters conveniently and observe the setting effect through the display function, so that it will be more convenient and convenient when operating the instrument.
      Feature 4: the mechanical design structure is optimized and reasonable. Good quality and reasonable structure of the solar climate testing machine, whether in function, or in safety and operation, will have a good advantage, so as to optimize the detection work is more advantageous.

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