Test method and coating composition impact on measured moisture vapor transmission rate for waterborne coatings on paper, TAPPI Journal November 2024

Application: Evaluation of moisture vapor barrier performance is critical for development and application of barrier coatings for paper packages. Understanding the impact of testing method and coating material on MVTR guides the assessment and implementation of waterborne coatings for different applications.

Author: Wenwen Mei, Dave Malotky, Kate Lusvardi, Brian Einsla, and Ray Drumright

ABSTRACT: Moisture vapor barrier is one of the necessary performance attributes for paper packages. Two methods are typically employed to assess the moisture vapor transmission rate (MVTR): the gravimetric cup method (ASTM E96) and the MOCON method (ASTM F1249). While those tests have been compared for free standing polymeric films, less is understood about their application in coated paper. Our results show that, despite a general agreement between the two methods, discrepancies exist where test protocols and material properties of coated paper impact the MVTR measurement. The measurement discrepancies can be explained by differences in local moisture concentration. Our study provides new insights on moisture vapor barrier assessment of waterborne coatings on paper and implications for achieving paper packages with improved barrier performance.