Urethane Grade vs Standard Ethyl Acetate

Urethane grade and standard grade are divided by water and ethanol, not by the purity figure. Two solvents at the same assay can behave completely differently in an isocyanate system.

Ethanol is the quieter of the two. It also consumes NCO, but it hides inside the assay number and never shows on a water test.

Petrochemical plant columns and pipework under a blue sky — Two lines on the certificate decide the batch: water and ethanol.

When buying, ask the supplier for water and ethanol on every lot certificate. Those two lines, not the assay figure, are what the formulation is standing on.

The published Sasol limits, water 0.03% max and ethanol 0.02% max, already cover most polyurethane systems. Formulations tighter than that are the ones that need a dedicated urethane grade.