STATISTICAL MODEL PREDICTING WATER VAPOR TRANSMISSION RATES OF HIGH-BARRIER-COATED PAPERS

摘要

Moisture barrier properties of extrusion-coated papers including EVOH-layer were investigated. The moisture barrier of EVOH is considerably compromised in the presence of moisture because the highly polar water molecule tends to hydrogen bond with the EVOH polar groups followed by plasticization of the polymer. To prevent the moisture effect, the EVOH-layer is typically covered with a non-polar skin layer. In addition to its own barrier, the skin layer improves the barrier of EVOH by decreasing its moisture concentration. This study introduces a practical model that estimates water vapor transmission rates (WVTR) of high-barrier-coated papers with an extrusion-coated EVOH-layer. The skin layer effect is taken into account when the WVTR is estimated as a function of coating structure at specific atmospheric conditions.