In recent years there has been a rapid increase in the use of various additives in recipes for papermaking. The chemicals used as additives interact with wood fibers and other added materials such as paper fines, starches, clays, carbonates, alum, and natural resins. As a result of this interaction, retention of fine particles to the fibrous sheet of paper is enhanced, and the properties of paper, such as wet or dry strength or printability, are improved.
Many of these additives are polyelectrolytes and possess anionic and cationic charges which vary as a function of pH and the use of other electrolytes in the papermaking system. Also, some chemicals are intended to change the particle size of fines, causing them to flocculate into larger aggregates.
In many instances a paper mill experiments with the use of such additives not in a pilot plant but on a production papermaking machine. Such experimentation is at great expense since malfunctioning caused by such very active additives can result in excessive machine downtime due to undesirable chemical residue and in build-up on papermaking machine surfaces and press fabrics.
Thus, experimentation involving such new additives or new procedures, as well as adjustments of other process parameters such as pH and concentration, are not advantageously carried out on a production papermaking machine. There is a need to develop another method of testing wherein the expense associated with testing on a production papermaking machine can be avoided.