Problem Solving Forum
November 9 - November 13, 2020
What is the difference between the coalescence mechanism and the solvent evaporation mechanism regarding the paint film formation?
Selected Answers
From
Zenith Czora of Durotech Industries, Inc. on
November 13, 2020:
Film coalescence is for waterborne or water-based ...read more
Film coalescence is for waterborne or water-based paints. It is the process of film formation when water evaporated and all polymer/pigment particles became concentrated and diffused together either with or with out the aid of coalescing agent. The degree of diffusions depends the softness or hardness of the polymer particles or the minimum film forming temperature of the polymer. On the other hand, evaporation mechanism is for solvent based paints where all the volatile liquids passed from the liquid state to the vapor state leaving the solids to diffuse together and dry up forming a continuous film. The evaporation rate of solvents influences the degree of cure of a solvent based coating.
From
Home Solomonea of Emerson on
November 13, 2020:
fusing of the particles ...read more
fusing of the particles
From
Jose Avendano of KTA-Tator, Inc. on
November 12, 2020:
In the coalescence mechanism, small particles of t ...read more
In the coalescence mechanism, small particles of the paint are suspended in an aqueous medium (emulsion). As the paint dries and the water in the emulsion evaporates, the particles coalesce to form the film. In the case of the solvent evaporation mechanism, the paint is diluted in the solvent, so the film forms as the solvent evaporates. That is why paints that form film by solvent evaporation have a fairly short drying time.