In the process of paint spraying, it is often found that although the paint has been carefully filtered, the construction site has been carefully cleaned, and there are good ventilation and purification facilities, there are still many mechanical impurities on the surface of the paint film. This phenomenon is more common in the drier season. Practice has proved that this is related to the static electricity generated during the spraying process.
There are roughly two reasons for the generation of static electricity. One is that when spraying paint, the paint mist sprayed by compressed air at high speed hits the substrate, and the friction between the paint mist and the air and the impact on the substrate generate static charges; the other is that most of the dust particles on the painting site are The paint that is not exhausted by the exhaust fan is mostly dry dust. Commonly known as paint dust, they can also generate and accumulate charges when they flow, especially these paint dusts are good insulators, and the accumulated charges are more significant.
When the painted workpiece is charged, it will attract dust in the environment. Similarly, charged dust will also be adsorbed to the painted workpiece due to electrostatic induction. Therefore, preventing the painted workpiece and dust from being charged in the environment is an important factor that cannot be ignored to ensure the quality of the coating.
Practice has proved that, except for some volatile paints (because their surface conjunctivates quickly and will not adhere to dust), it is feasible to take the following descriptions to prevent the accumulation of charges and prevent the adsorption of raw soil.
1) Take good environmental purification and reduce surface mechanical impurities.
2) Spray more water on the ground before construction, which can not only reduce the flying of dust, but also increase the relative humidity in the air, which is conducive to the leakage of electric charge.
3) Metal products should be used for the turntable and hooks for hanging and placing the painted workpieces to facilitate the elimination of electric charges. And often remove the old paint layer.
4) The drying room also needs to be cleaned and wiped frequently, so as to ensure the cleanliness of the drying room and prevent the workpiece from absorbing dust when it enters the general room
5) The air pressure should generally be controlled at 0.3-0.5MPa when spraying paint. If the pressure is too high, the flow rate of the method will be large. The friction with the air will be large, and the charge generated will be stronger, which will also make the workpiece likely to absorb dust. sex increased.
6) Before painting, you can try to add a very small amount of polar solvents, such as acetone, acetyl acetate, butyl acetate, methanol, etc., into the paint can, or add a small amount of antistatic agent.
7) The workpiece should be grounded separately to form a loop and eliminate static electricity.
