Property Development On Coated Paper and Board; Considerations In Choosing The Right Finishing Technique, 2004 Coating and Graphic Arts Conference

Perhaps the most intriguing area in the subject of calendering is the development of the final gloss and smoothness of a given sheet of paper along with the required properties such bulk, opacity, and other critical parameters. As producers of paper look to produce a certain level of gloss or smoothness on a sheet, they look at coating formulations and additives that can enhance the levels of those properties. The relationship between the other properties that a sheet may require and those of gloss and smoothness can often be counterproductive from a finishing standpoint. Papermakers make compromises based on the fiber supply and a variety of other parameters that influence the final sheet properties. However, we recognize that the equipment used to develop the gloss and smoothness has its own set of parameters that can influence the final product and there are hidden advantages and trade offs in every technique. This paper looks at the types of equipment that is offered and gives some examples of where it might typically be applied. The paper also looks at the parameters that need to be flexible for proper control of the process for different grades and what areas have evolved in recent years. Finally, a couple of case studies are shown where the initial equipment selection turns out to be less favorable than an alternative method of finishing the sheet.