Dent Test for EEP, MMP, and PMA

Experimental Purpose

Using PPG one-component primer (P565-9085) as the test medium, this experiment evaluates and determines whether the solvents contain anti-wetting agents, silicones, or other substances that can open the paint film (paint) and cause cratering or other defects. This is done by observing the occurrence of sink marks (craters) on the coated surface after spraying the new solvents EEP (ethyl 3-ethoxypropionate), MMP (methyl 3-methoxypropionate) and the conventional solvent PMA (propylene glycol monomethyl ether acetate).

Experimental Conditions and Tools

Experimental Procedures

Clean the substrate aluminum plate with MEK and a lint-free towel, and place it on a level surface.
Use a dropper to transfer approximately 2mL of the sample to be tested and drop it onto the aluminum plate from left to right. Drops should increase in size, with three rows of four drops each, forming a final “Z” pattern.
Immediately spray the white paint onto the substrate from a distance of 10-15 cm, in 1-2 steps. Visually, the substrate must be covered, but the coating should not be too thick (remember to shake the paint well before spraying).
Immediately check the panel for dent formation.
Inspection Standard Pass: 0 dents Reject: ≥1 dents		PASS

Experimental Conclusion

1. These three ether-ester solvents, EEP, MMP, and PMA, do not significantly reduce the surface energy of the substrate when present as residue.
2. In actual application, if there is minor residue of such solvents (e.g., incomplete wiping, previous coat not fully dry), the risk of them causing cratering is low.
3. In actual application, if there is minor residue of such solvents (e.g., incomplete wiping, previous coat not fully dry), the risk of them causing cratering is low.

For further details on PREC’s functional solvents, please visit: Solvant PREC EEP et PREC MMP Solvant.