Volatile Behavior
A physical phenomenon of solvent trapping in printed polymers or paperboard coatings occurs when volatile carrier liquids remain within the dried ink film. This phenomenon of ethanol retention refers specifically to the presence of residual ethyl alcohol that fails to evaporate during the drying phase of flexographic or gravure printing. Substrate absorption and high-speed runs often exacerbate this behavior, as the ink surface seals before the underlying solvent escapes.
The amount of trapped compound directly influences the physical properties of the finished packaging material.
Analytical Quantification
Testing procedures utilize gas chromatography to measure the precise concentration of the solvent in milligram units per square meter of printed stock. During this process, ethanol retention is assessed by heating a known area of the packaging material inside a sealed vial to liberate the volatile components. The gaseous headspace is then injected into a separation column for detection.
High values indicate inadequate airflow or excessive drying temperatures on the production line.
Packaging Risk
Excessive amounts of this solvent can migrate into the packaged food, causing off-flavors or odor issues that violate consumer safety standards. This migration is particularly problematic in dry-food carton packaging, where the interior board lacks a functional barrier coating.
