Effect of Temperature and Humidity on Aging Test in Tape Aging Tester

I. Effect of Temperature on Aging Test in Aging Test Chamber

As the effect of light is always accompanied by a rise in temperature, the increase in temperature is also an important factor in the aging of the anti-corrosion coating. The thermal aging of the usual anti-corrosion coating is mainly due to the cross-linking process and the destruction of the polymer molecular chain; as a result of the cross-linking, a three-dimensional structure is generated to make the anti-corrosion coating hard, brittle and lose elasticity; and the molecular chain breaks As a result, macromolecular chains are broken, the molecular length and molecular weight are reduced, free radicals are formed, and they appear soft and sticky. It is roughly estimated that if the temperature rises by 10 degrees Celsius, the chemical reaction rate will increase twice. However, the photochemical reaction is not a simple one-step reaction. The initial photochemical reaction is not affected by heat, and the second reaction is affected by heat. Its effect is more important than pure heat aging. In artificial weathering tests, certain temperatures combined with periodic rainfalls cause frequent alternating temperatures, as this will cause continuous expansion and contraction of the coating and substrate, which can cause significant stress in the coating. In most cases, the composition of the anti-corrosion coating contains substances of different composition and structure: primer, intermediate paint, pigmented paint, topcoat, and therefore due to stress in each coating when subjected to temperature changes. Differently, with strong light with a certain wavelength, it is easy to cause cracking of the anti-corrosion coating.

Second, tape aging tester on the impact of humidity

Exposure to the atmosphere, the anti-corrosion coating is actually kept in a wet state for a long period of time, especially in the humid tropics. The influence of moisture is also very complex, mainly including: chemical reactions, physical effects, erosion, absorption / freeze - thaw, and thermal shock. In high humidity conditions, moisture rapidly penetrates into the interior of the anti-corrosion coating. The anti-corrosion coating may cause dissolution or swelling due to the absorption of moisture, change in volume, or dissolve water-soluble substances in the anti-corrosion coating when in sunlight. In particular, under the irradiation of ultraviolet light, its volume rapidly expands, the structure is damaged or the photochemical change is accelerated, and blistering, rusting and falling off are easily generated. In particular, the dew is rich in oxygen and stays on the coating surface. The time is much longer than the rain. The main cause of outdoor wetness is dew, not rain.