Impact of Paper Properties on the Success of In-Line Aqueous Coatings, 1996 International Printing & Graphic Arts Conference Proceedings

Nancy Plowman Sandreuter, President

Nancy Plowman Associates, Inc.

In sheet fed offset printing, the trend over the past 5 years has been to replace the use of the traditional gloss overprint varnish with an application of water-based gloss coating. These coatings are formulated using co-polymer systems of styrene and acrylics and are applied as a wet film over the wet inks. These coatings dry quickly and offer good gloss and fast turnaround. Most desirable of all they can reduce the amount of anti-offset spray powder used, yielding an extraordinary smooth printed product. Because these coatings are applied over the wet ink, the absorption characteristics of the paper or board coating play a major role in the overall success of the job. This paper describes testing results of printed jobs where the paper and/or board characteristics yield pass/fail results. The role of the ink formulation, ie resin and oil choice, is discussed. In particular ink setting times, abrasion resistance and the compatibility with certain fountain solution chemistries are also discussed.