The experimental comparison between artificial aging of powder coating and natural aging.

China Coating Network
News: Powder coating film curing, due to various external influences, such as light, oxygen, heat, humidity, high and low temperature alternating, ozone, salt spray, and oil, acid, alkali environment, resulting in
coatings
, plastics and other organic materials damage, chemical structure damage, so that the original performance lost. These injuries include loss of luster, discoloration, yellowing, cracking, peeling, brittleness, loss of strain and lifting. Even indoor light and sunlight through window glass degrade certain materials such as pigments and dyes, a phenomenon known as aging. Aging experiments can be divided into two categories: one is natural sun exposure aging, the other is artificial aging experiments.
We selected different pigments to be added to the same polyester/TGIC
powder coating
, respectively, for outdoor natural exposure and QUV artificial accelerated aging experiments, recording sample gloss and color changes in the experiment.
experiments because of the world's outdoor natural exposure is very different, here selected the Climate of Wuhan, Hubei Province for reference only. Outdoor natural exposure is carried out in strict accordance with GB/T9276ISO4628 "Coating Natural Exposure Experiment Method". The back plate of the test sample is a 1.6mm thick splint, the test frame is 45 degrees, facing south.
artificial accelerated aging test is performed in accordance with GB/T1865ISO11341 Coating Aging (Artificial Acceleration) Determination Method (Considered Xenon Arc Radiation). The experimental equipment is a UV accelerated aging test machine. The test case has closed-loop feedback loop system control, which can set and control the intensity of UV light irradiation. The UVA-340 UV lamp was used in the experiment, with a peak light strength of 343nm and a cut-off point of 295nm. In order to exclude the effect of different temperatures on the experimental results, the test temperature is uniformly set at 50 degrees C.
conditions: 4h ultraviolet light exposure, 4h condensation; The irradiation point of the UVA-340 lamp is controlled at 0.68W/m2@340nm and the temperature of the entire test cycle is controlled at 50C. The intensity of ultraviolet irradiation in this test cycle is equivalent to the sunlight at noon in summer.
Outdoor natural exposure in the beginning of the first month PY191 light color plus titanium white show a very slight loss of light and color, exposure after 5 months half of the pigment model has a slight loss of light and significant color change, after a year of exposure only BGS indistinct blue, PG-7 indistinct green is very slight loss of light and slight color change. The artificial accelerated aging instrument in the beginning of 100 hours there are individual very minor loss of light and color change comprehensive rating of 0, 200 hours PY191 has a clear comprehensive rating of 0, PY191 loss of light significantly color change serious, PY254 light loss, serious color loss, PY81 serious loss of light and color.
we usually say, pigments to ensure that a few years of unchanged color, specifically to ensure that a few years is actually a vague expression. Only the weather resistance level detected under standard conditions can be agreed upon. Such as: different areas of the location of exposure to the sun, formula stability of the premise conditions and other factors.