Functional Barrier Efficiency

Evaluation Method

Testing involves exposing a coated paperboard sample to a simulated contaminant on one side while measuring the amount that passes through to the opposite side over a fixed period. High performance barriers must stop migration completely, which is assessed through gas chromatography of the enclosed atmosphere or direct extraction of the food simulant. The test determines the percentage of substance blocked, where a higher percentage denotes superior protection against volatile compounds.

Factors such as coating thickness, polymer crystallinity, and temperature influence this rate of migration.

Converting Impact

Mechanical stresses during the creasing and folding of the boxboard can fracture thin barrier layers, reducing the protection level at the corners of the finished box. Process adjustments must balance the rigidity of the protective polymer with its flexibility to maintain the barrier after conversion. This protection rating ensures that the final package keeps the contents fresh and free from off-flavours while avoiding the need for expensive foil laminates.