Protective Barrier
Protective layers applied to paperboard substrates prevent the migration of undesirable substances from recycled fibres into packaged foodstuffs. The application of a functional barrier coating blocks the transmission of mineral oil saturated hydrocarbons and aromatic hydrocarbons. This polymer layer must maintain its continuous structure across the entire surface of the board to remain effective.
It replaces traditional plastic liners while preserving the recyclability of the paper carton.
Coating Application
Modern converting lines apply these barrier materials using blade, rod or curtain coating stations during the board-making process. The water-based polymer dispersion is distributed evenly across the paperboard web to form a thin dry film. This procedure requires precise control over drying temperatures to avoid pinhole formation or cracking in the barrier.
The resulting surface must also allow for trouble-free gluing and printing on high-speed packaging lines. Operators adjust the coating weight to balance barrier performance with material cost.
Migration Prevention
The performance of the coated board is verified through long-term storage tests with food simulants. If the barrier is uniform, the migration of volatile compounds remains undetectable over the designated product life. This barrier prevents off-flavors and chemical contamination.
Food brands rely on this technology to meet safety standards without using foil.
