Starch addition

1. Wet-end starch improves drainage and many sheet strength properties, primarily due to its influence on internal bond
2. A lack of starch at the wet end may lead to poor drainage and first-pass retention along with lower strength responses.
3. Starch usage in excess of what is needed to produce its intended effect can reduce drainage, increase BOD and COD in the wastewater, and may actually interfere with internal bond.
4. Starch can be used to enhance sheet strength without refining, thus providing a softer dry-creped sheet.
5. Oxidized starches added at the wet end or returned to the stock system with broke or recycled fiber use can interfere with the retention of both fines and fillers.
Refer to Chemicals, wet end.