The mass of a dried coating per unit coated area, commonly expressed in g/m²; for blister materials, the coating layer being specified must be identified.
Also called: dry coat weight; coating weight; coat weight; heat-seal coating weight; dry coating mass per unit area.
What does dry coating weight measure?
Dry coating weight is the remaining dry coating mass per specified area, commonly g/m². It excludes the volatile portion of a wet coating and the mass of the supporting substrate. State the drying and measurement basis when comparing values.
Identify the layer and side being reported, the area basis and whether the figure is a target or measured result. The mass of the whole coated foil includes the substrate and other layers; it cannot be called the dry heat-seal coat weight without separating those contributions. Historical lb/ream figures also need the stated ream-area basis before conversion.
No: it is mass divided by area. A thickness conversion additionally needs the relevant coating density and assumptions about the layer. Likewise, a wet application mass requires the dry-solids fraction before it can be compared with dry coat weight. Chemistry, substrate and heat-seal conditions still determine the resulting bond.
An area-average mass can conceal uneven local coverage. State the sampling or measurement basis when relating coat weight to sealing performance.