Coating process: Test for weather resistance and light resistance of coating

It is suggested that coatings, plastics and other organic materials will lose light, fade, turn yellow, peel off, crack, lose tensile strength and fall off of the whole layer after exposure to natural climate conditions and light radiation for a period of time Even indoor light or sunlight through windows can cause damage to substances such as pigments or dyes Therefore, for outdoor coatings, such as exterior wall coatings and automobile coatings, weatherability and lightfastness are the most important coating testing items Generally used are natural climate aging test, xenon arc lamp irradiation, carbon arc lamp irradiation, ultraviolet lamp irradiation and other artificial accelerated climate Shenyang steel structure fireproof coating construction expert punde Building Fire Engineering Co., Ltd Recommended introduction: since its establishment, Shenyang punde Construction Fire Engineering Co., Ltd has cultivated a group of professional construction teams with excellent equipment, rich experience and serious responsibility with advanced and scientific management methods and strict engineering quality assurance and after-sales service system It has undertaken a number of fire system installation projects, which has been praised by customers Every idea and special requirement of you will be fully considered by us and fully realized in the construction technology, which will become the cornerstone of our successful long-term development We are looking forward to your invitation, to provide you with quality services and high-quality technical support! All construction coatings have passed ISO9001 Paint Home News: paint, plastic and other organic materials exposed to natural climate conditions and light radiation may lose light, fade, turn yellow, peel off, crack, lose tensile strength and fall off of the whole layer after a period of time Even indoor light or sunlight through windows can cause damage to substances such as pigments or dyes Therefore, for outdoor coatings, such as exterior wall coatings and automobile coatings, weatherability and lightfastness are the most important coating testing items The commonly used methods are natural climate aging test, xenon arc lamp irradiation, carbon arc lamp irradiation, ultraviolet lamp irradiation and other artificial accelerated climate aging test 1 natural climate aging test natural climate aging test method is widely used at home and abroad The main reason is that the experimental results of natural climate aging are more practical, the cost is lower and the operation is simple and convenient Although we can carry out the natural climate aging test anywhere, the internationally recognized test site is Florida in the United States, because it is sunny However, the disadvantage of natural climate aging test is that the test takes a long time, and the test personnel may not have so many years to wait for the test results of a product In addition, even in Florida, the climate cannot be the same year after year, so the reproducibility of the test results is not ideal However, the disadvantage of natural climate aging test is that the test takes a long time, and the test personnel may not have so many years to wait for the test results of a product In addition, even in Florida, the climate cannot be the same year after year, so the reproducibility of the test results is not ideal Xenon arc radiation test xenon arc radiation test is considered to be the best test to simulate the whole solar spectrum, because it can produce ultraviolet, visible and infrared light Because of this, it is considered to be the most widely used method at home and abroad This method is described in detail in GB / T 1865-1997 (equivalent to ISO 113411:1994) However, this method has its limitations, that is, the stability of xenon arc lamp and the complexity of the test system Xenon arc light sources must be filtered to reduce unwanted radiation In order to achieve different irradiance distribution, a variety of filter glass types can be selected The choice of glass 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 transmission, thus changing the speed and type of material damage There are three types of filtering commonly used: sunlight, window glass and extended ultraviolet (method 1 and method 2 mentioned in GB / t1865-1997 correspond to the first two types) Typical xenon arc radiation is equipped with an irradiance control system The irradiance control system is very important in xenon arc radiation test, because the inherent stability of xenon arc light source is worse than that of fluorescent UV light The spectral difference between a new xenon arc lamp and an old one which has been used for 1000 h has been investigated abroad The results show that the spectral energy distribution changes significantly not only in the long wavelength range of the light source with the extension of the lamp use time, but also in the short wavelength range This change is caused by the aging of xenon arc lamp, which is its own internal characteristics There are also many remedies available for this change For example, increase the frequency of lamp replacement to reduce the impact of light aging Or the irradiance can be controlled by sensors Despite the change of spectral energy distribution caused by lamp aging, xenon arc lamp is still a reliable and practical light source for weather resistance and sunlight resistance test In most xenon arc radiation tests, water spray and / or temperature automatic control system (surface water spray proposed in GB / t1865-1997) are used to simulate wetting conditions The limitation of water spray method is that when the water with relatively low temperature is sprayed on the test plate with relatively high temperature, the test plate will cool down, which will slow down the process of material damage In the xenon arc radiation test, it is required to use high purity water to prevent the deposition on the surface of the test plate Therefore, the operation cost is high 3 ultraviolet lamp irradiation test ultraviolet lamp irradiation aging test uses fluorescent ultraviolet lamp to simulate the destructive effect of sunlight on durable materials This is different from the xenon arc lamp mentioned earlier The fluorescent UV lamp is similar to the ordinary cold light fluorescent lamp in electrical principle, but it can generate more ultraviolet light than visible light or infrared light For different exposure applications, there are different types of lamps with different spectra to choose from The UVA - 340 lamp can simulate the sunlight well in the main short wavelength ultraviolet spectrum range The spectral energy distribution (SPD) of the UVA - 340 lamp is very similar to that of the 360 nm spectrum from the solar spectrum UV - B lamp is also commonly used to accelerate artificial climate aging test lamp It is faster than UV-A lamp to destroy materials, but its shorter wavelength energy output than 360 nm will cause many materials to deviate from the actual test results Irradiance (light intensity) control is necessary for accurate and reproducible results Most UV aging test devices are equipped with irradiance control system These precise irradiance control systems enable users to choose the irradiance measurement when they do experiments Through the feedback control system, the irradiance can be continuously and automatically monitored and accurately controlled The control system automatically compensates for the insufficient illumination caused by lamp aging or other reasons by adjusting the lamp power Because of its inherent spectral stability, the control of irradiance is simplified All light sources weaken with time However, unlike other types of fluorescent lamps, their spectral energy distribution does not change with time This feature improves the reproducibility of the test results, so it is also an advantage Some tests show that there is no obvious difference between the output power of a lamp used for 2 hours and that of a lamp used for 5600 hours in the aging test system equipped with irradiance control, and the irradiance control device can maintain the constant light intensity In addition, their spectral energy distribution has no change, which is very different from xenon arc lamp One of the main advantages of using purple light aging test is that it can simulate the damage effect of outdoor humid environment on materials When the material is placed outdoors, it is estimated that at least 12 hours a day will be frequently affected by moisture Because this kind of wet action is mostly in the form of condensation, a special condensation principle is used to simulate outdoor humidity in accelerated artificial climate aging test In such a condensation cycle, the tank at the bottom of the chamber is heated to produce steam The hot steam keeps the environment of the test chamber at 100% relative humidity under high temperature In the design of the test chamber, the test plate should actually form the side wall of the chamber So the back of the test panel is exposed to indoor air at room temperature The cooling effect of indoor air makes the surface temperature of the tested panel lower several degrees than that of the steam The temperature difference can make the water continuously drop to the tested surface during the condensation cycle The condensate thus produced is pure distilled water of stable nature This kind of water can improve the reproducibility of experimental results, eliminate the problem of water sediment pollution and simplify the installation and operation of test equipment Because the material is usually wet for a long time outdoors, a typical circulating condensation system needs at least 4 hours of test time If the condensation process is carried out under the condition of heating (50 ℃), it will greatly accelerate the damage rate of moisture to the material The long-term and heated condensation cycle can more effectively reproduce the damage of materials in humid environment than other methods such as water spray, immersion and other high humidity environment Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,