ã€China Aluminum Network】 The durability of the coating is the service life of the coating. This is a more important quality indicator for paints and coatings. It is a comprehensive manifestation of various properties and is a reflection of the true practical value of coatings. The durability of the coating is the durability of the coating itself to the atmosphere, so the weatherability test of the coating is very necessary. This is the key to improving the weather resistance of the coating film and improving the quality of the coating product. There are two main methods for durability testing of coatings, namely atmospheric aging test and artificial accelerated aging test.
1. Atmospheric aging test
In the course of use, the coating is subjected to a variety of different factors, which cause the chemical and mechanical energy of the coating film to cause irreversible changes, eventually leading to the destruction of the coating. This change phenomenon is called the aging of the coating film.
The atmospheric weathering test of coatings is to study various factors of the atmosphere, such as sunlight, wind, snow, rain, dew, temperature, humidity, oxygen, chemical gases, etc., in the various climatic regions. Through the inspection of the appearance of test panels to identify its durability.
The atmospheric weathering test method for paints, according to the national standard GB1767-79 (confirmed in 1989) "Testing method for weatherability of paint film", GB9276-88 "Guiding document for natural aging test of paint and varnish coating", GB1766 -79 (Confirmed in 1989) "Grade Film Weathering Rating Method" and GB 9277.1 - 5 - 88 "Plainness of Color Coating Coating Aging" and other prescribed methods require that the coating be tested for ageing resistance.
Atmospheric aging tests, due to geographical, seasonal, environmental and other factors are quite complex and time-consuming.
It is also quite complicated and difficult to carry out tests and tests in full accordance with actual conditions. It is also difficult to obtain accurate results. Therefore, the testing methods for the durability of coating films are also constantly improving. Artificial accelerated aging test is an improved one.
2, artificial accelerated aging test
The accelerated weathering test was based on the atmospheric weathering test and found out the relationship between climatic factors and film failure. In order to artificially create a simulated climatic environment in the laboratory, to carry out film aging tests of various types of climate, and to give certain acceleration of catalytic factors, in order to overcome the short exposure of natural exposure test.
From the atmospheric weathering test, the main influencing factors for aging are mainly light sources in terms of environmental conditions. The light source is a very important factor in the aging of the coating film, and has a direct relationship with the type of light and the amount of radiation. In particular, ultraviolet radiation is more destructive to the coating film. The temperature, humidity, and oxygen content in the atmosphere all play an important role in the aging of the coating. Artificial aging test is the use of a certain equipment that is artificial aging machine, by changing the type of light source, strength, and various types of climate, temperature, humidity, changes in the amount of oxidation control and other factors. To monitor the degree of aging and change of various coating films in an artificial climate, and to measure the aging resistance of the corresponding film, that is, the aging resistance.
Artificial accelerated aging test, this artificial simulated climate environment is not the same as the actual environment, there is a certain degree of access, so the measured resistance to aging is an approximation, it is unlikely to be the same in a very different real environment. This artificial accelerated aging test is also constantly developing, and this approximate value is becoming more and more accurate.
In this chapter, the inspection content and method of coating quality, especially the detection of the performance of coatings and coating films, are described in more detail. However, in the actual coating production and painting and maintenance, it is not possible to carry out all of the above sub-items. Monitoring, according to the specific conditions of production or maintenance, according to the specific requirements of the production process or maintenance process for the necessary testing.
Natural exposure test
Putting the coating in the natural environment and observing changes in its performance over time can truly reflect the influence of the coating on various types of comprehensive environmental factors, and can accumulate applicative application data for the durability of the coating.
Samples and test plates were prepared according to GB3186-1982 and GB/T1765-1979, respectively. The test site is flat, open and free of water. Other conditions are in accordance with the provisions of GB/T9276-1996. The manufacturing and installation methods of the exposure test racks were performed according to GB/T9276-1996. Gloss and color were measured according to GB/T9754-1988, GB/T97611988, and GB/T11186.2-1989. The aging evaluation of the coating was conducted according to GB/T1766-1995.
A captive bolt pistol (also variously known as a cattle gun, stunbolt gun, bolt gun, or stunner) is a device used for stunning animals prior to slaughter.
The principle behind captive bolt stunning is a forceful strike on the forehead using a bolt to induce unconsciousness. The bolt may or may not destroy part of the brain.
The bolt consists of a heavy rod made of non-rusting alloys, such as stainless steel. It is held in position inside the barrel of the stunner by means of rubber washers. The bolt is usually not visible in a stunner in good condition. The bolt is actuated by a trigger pull and is propelled forward by compressed air or by the discharge of a blank round ignited by a firing pin. After striking a shallow but forceful blow on the forehead of the animal, spring tension causes the bolt to recoil back into the barrel.
The captive bolt pistols are of three types: penetrating, non-penetrating, and free bolt. The use of penetrating captive bolts has, largely, been discontinued in commercial situations in order to minimize the risk of transmission of disease.
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