Drying Considerations for Coatings Applied to Thin Films

Presented by Dan Bemi, MEGTEC Systems

In an effort to maximize profitability in an ever more competitive market, film converters have been forced to address the challenges associated with running faster line speeds, thinner substrates, thinner coatings and wider webs. Within the drying section of a typical coating/laminating machine, these challenges include both web-handling concerns and the drying process itself.

The purpose of this paper is to define some of the key problems associated with the drying of coatings on thin films and to identify the equipment and processing techniques that are typically used to address these challenges. Due to the broad scope of the subject matter, the author will not attempt to identify or discuss at length, the full range of considerations or permutations of variables that may come to play when drying coatings on thin films. Rather, in the interest of time and the desire to provide some realistic and useful recommendations for thin film drying, we will limit our discussion to some of the most frequently encountered challenges and the associated range of potential solutions as they relate solely to (flotation and roll support) convection air drying systems. Finally, for the purposes of this paper, we would like to define thin films as films ranging in thickness from less than 0.25 mils to 3 mils.