Analysis Of Causes Of Teflon Spraying Shrinkage

Analysis of Causes of Teflon Spraying Shrinkage

(1) Reasons during the construction process
Poor degreasing of the substrate, adhesion of foreign matter such as water, oil, dust, and abrasive ash;
Silicone and wax are used in the surrounding area, and dust and paint mist are present in the coating environment;
The coating environment temperature is too low and the humidity is too high.

(2) Equipment and machine reasons
Compressed air drying equipment or oil water separator failure, resulting in the incorporation of moisture and paint;
Paint tools, equipment, overalls or gloves are not clean.

(3) Reasons caused by materials
The coating used has a low surface tension and poor fluidity, and is itself sensitive to shrinkage cavities;
Defects in coating formulation used: The coating contains actives with low surface tension, such as defoaming agents and other fluorine-based additives added with poor compatibility or excess; a small amount of macromolecular polymer in the resin aggregates to produce solvent-insoluble glue. The surface tension of the granules is lower than that of the tree solvent, and shrinkage cavities appear immediately after the coating film is formed.


Teflon spray shrinkage, depression and fisheye
During the coating construction process, the coating film is affected by foreign matter (low surface tension material), causing the paint film to flow from a low surface tension point to a high surface tension point, shrinking to form a pit.

Shrinkage holes often exhibit different shapes. According to different surface states, some special state shrinkage holes are also called depressions and fish eyes. The paint film shrinks severely even to the coated substrate, and there is no core particle in the middle, and the shrinkage hole which is large in shape and approximates a circle is also called a depression. There is a core particle in the middle of the shrinkage hole, usually dust particles or batt covered with liquid oil droplets, and the shape is similar to the fisheye.

Shrinkage defects are common surface ills in coating production, and sometimes become major defects in production, which may occur in large batches in a continuous manner, leading to discontinuation in severe cases. Moreover, many defective parts cannot be reworked and scrapped, resulting in a significant waste of resources.