A feasible method to prevent the speed of aging of the GI steel coil in advance.
GI steel coil with spangles made in China used for a long time or not used for a long time may occur aging, why to say it, long-term construction or storage will be exposed to the sun. Aging occurs after a long time of exposure to light, which we cannot avoid. However, we can prevent and reduce the aging rate in advance in ordinary times. So what should we do?
The first necessary condition for aging or photochemical reaction of PPGI corrugated roofing sheet is that the surface composition of PPGI sheet can absorb radiation energy. Secondly, the absorption of molecular radiation energy is greater than the molecular bond energy, the color coating can occur degradation. The shorter the wavelength, the higher the energy.
According to the above theory, the aging of the
high quality PPGI corrugated roofing sheet in the atmospheric environment is that the coating molecules absorb the energy of the ultraviolet band in the sunlight which is higher than its molecular bond energy, leading to the degradation of the coating molecules. With the aging of the coating, the base material body is gradually lost, and the coating surface gradually becomes rough and lose light. This loss of base material eventually leaves relatively stable pigment particles in the form of an unbonded powder on the coated surface, a process known as pulverization.
To sum up, there is a big difference in the aging resistance of polyester color coating board with different coating thickness, the aging resistance of thin coating color coating board is poor, the aging resistance of normal thickness coating is relatively good.
Therefore, it is not feasible to reduce the production cost of PPGI corrugated roofing sheet by reducing the thin coating, which will inevitably bring serious quality problems.
