THE SUBSTRATE-BARRIER FILM INTERFACE IN THIN BARRIER FILM COATING

For vacuum web coating for permeation barrier coatings in flexible pac kaging, the final functionality of the packaging media is extremely de pendent on the whole chain of processing steps up to the final laminat ed packaging film. The most sensitive sector appears to be, on the one hand the hand-shake between substrate film pretreatment-substrate sur face properties and the coating process with its characteristics on th e other. The influence of different surface pretreatment processes (Co rona activation, oxygen and ammonia plasma treatment) on active surfac e groups of BOPP (biaxial-orientated polypropylene) substrates is show n together with: (1) specifities of the thermal deposition (electron b eam source). (2) the reactive deposition-microwave plasma process (pla sma species, excitation characteristics, kinetic energies, obtained by in situ process monitoring); and (3) structural properties (chemical composition, adhesion and oxygen permeation) of the thin barrier films (Al2O3 and SiOx); in correlation with the achieved functional propert ies of the barrier coated films. (C) 1997 Elsevier Science S.A.