One Thousand Pilot-Coater Trials Lead to Advances in Paper-Coating Development, 2002 Coating Conference Proceedings

A. D. Hickman and R. Urscheler

Pilot-coating and finishing facilities have been operated for over 40 years to assess new equipment, develop new coating materials and paper grades, and solve product and process problems. Much has been learned over these years to improve methods for planning and conducting trials. Furthermore, much information has been gained to reduce risks for new machine start-ups and rebuilds and improve current mill coating and finishing operations. This paper presents information gained from over 1,000 trials between 1996 and 2001 at The Dow Chemical Company’s two pilot coaters, located in Horgen, Switzerland and Midland, Michigan USA.

The purpose of pilot-coater trials and the practical experience gained from running these trials is shared along with suggestions for trial planning. The trends of increased use of pre-metered size press, fountain application (jet), and on-line finishing are confirmed based on increased numbers of trials using these practices. Findings from different sets of trials are discussed in detail, highlighting the purpose, trial plans, and results. These trials include use of pre-metered size press, jet and flooded-nip applications, supercalendering, and on-line hot/soft calendering. As a practical extension of jet developments, a means to reduce coating nonuniformity due to air entrapment is discussed.