Retention

1. Retention is affected by all the materials in the system; notably the fiber type, refining, filler grades, sizing, starches, biocides, defoamers and ionic charges.
2. The system components, together with retention aids, all work simultaneously both for and against stability in the system.
3. Retention aids are non-discriminating; they tend to attack equally all solids in the system.
4. White water composition or more precisely, variations in white water composition directly affect retention and process stability.
5. To avoid retention disturbances, fines management around the paper machine is essential.
6. Improved first-pass retention reduces headbox consistencies thus contributing to better fiber dispersion and improved quality.
A related topic is Drainage aids.