The main reasons for blistering during spraying of indoor matte powder coatings include the following:
Improper Substrate Preparation:
The presence of oil, moisture, or other impurities on the substrate surface weakens the adhesion between the coating and the substrate, leading to blistering.
Inappropriate substrate surface roughness also affects the adhesion of the powder coating, resulting in bubbles.
Coating Intrinsic Issues:
Some components in the coating may generate gases during curing. When these gases cannot escape, they form bubbles within the coating.
Quality issues with the coating itself, such as the presence of moisture, impurities, or other undesirable components, can also cause blistering.
Improper Process Parameter Settings:
Inappropriate settings for process parameters such as electrostatic voltage, spraying distance, and spray gun adjustment can lead to uneven powder distribution on the substrate surface, resulting in bubbles.
Improper spraying methods, such as excessively thick coating or excessively fast spraying speed, can also cause powder accumulation, leading to bubbles.
Inappropriate Curing Conditions:
Improper settings for curing temperature, time, and other conditions can affect the curing process of the coating, leading to bubble formation.
Excessively high curing temperatures or excessively long curing times can exacerbate bubble formation.
Spraying Operation and Environmental Issues:
The operator's skill and experience significantly impact spraying quality; improper operation can lead to blistering.
Controlling the spraying environment, such as temperature and humidity, is also crucial; high humidity levels are particularly prone to causing blistering.
In summary, to avoid blistering during the re-spraying of indoor matte powder coatings, a multi-pronged approach is needed, including rigorous substrate preparation, selection of high-quality coatings, appropriate process parameter settings, optimization of curing conditions, improvement of spraying operation skills, and improvement of the spraying environment.
