Effect of Pigmenting and/or Sizing With a Pre-Metering Size Press on Coated Paper Quality, 1993 Coating Conference Proceedings

The application of starch on the paper machine by means of a pre-metering size press has become a firm part of today’s papermaking. As a modern application unit, the pre-metering size press also offers the possibility to apply mediums with high solids content and high viscosities. That is why this tried-and-tested concept is becoming an interesting alternative in the field of “Machine Finished Pigmented” (MFP) and “Machine Finished Coated” (MFC) paper grades as well as for pre-coating of coated paper. Economic and quality benefits can be achieved by using a pre-metering size press.

This paper discusses the effect of sizing and/or pigmenting with the pre-metering size press on different paper grades. Special emphasis will be given to the influence of the pre-treatment for coated paper grades.

First, the present fields of pre-metering size press application are shown briefly. Continuing from this point, basic principles are discussed with regard to two important questions:

1. How can we classify the various application systems related to the different requirements?

2. What are the main quality requirements for printing papers and how can they be achieved.

The influence of an additional treatment with the pre-metering size press will be explained by means of a schematic diagram of coated paper.

Next, the experience from a set of trials in a pilot plant concerning a comparison between coated paper grades with and without pre-treatment on a pre-metering size press will be reported and discussed. Furthermore, the pre- metering size press becomes more and more significant in other areas of use which should also be of interest, particularly due to the current market conditions.

In closing, benefits in using such an application unit as well as the potential fields which will be the focus in the future will be demonstrated.