Paper-based flexible packaging material with high barrier properties and a process to produce it

A process for improving barrier properties of polymer dispersion coated paper-based flexible packaging materials comprising:

• applying an Al2O3 coating having a thickness in the range of 8-70 nm, to at least one surface of the polymer dispersion coated paper-based flexible packaging material, wherein the Al2O3 coating is applied to the at least one surface of the polymer dispersion coated paper-based flexible packaging materials by atomic layer deposition at a temperature in the range of 40° C.-80° C. with trimethylaluminum (TMA) and H2O or O2 as precursors,
• wherein the process further comprises a plasma pre-treatment of the at least one surface of the polymer dispersion coated paper-based flexible packaging materials before the Al2O3 coating is applied.