Date of Award
Bachelor of Science
Paper Science and Engineering
Predicting the performance of drainage aids in a linerboard furnish is a difficult task. Existing tests such as the Canadian Standard Freeness test, Schopper-Riegler, and drainage tube are not adequate tests. These tests only simulate one-half of the paper machine. Unfortunately the section they model is of minor importance in linerboard.
The findings of this project suggest that linerboard is more dependent upon the vacuum induced drainage zone than it is on the free drainage zone. The vacuum zone is dependent upon the formation of the sheet. Therefore, if the formation of the sheet is improved the couch solids will go up. During the machine trial the formation was increased by dispersing the fibers with anionic polymers.
To better predict drainage aid performance it was found the stock should be deposited on a wire be a jet or slice rather than from a standing head of pulp. Once the stock is deposited, and a uniform mat formed, vacuum should be applied. This series of events is more realistic of a paper machine. The results obtained from such a test was found to be more representative of actual machine trial data.
Iman, Craig D., "Drainage Dynamics in a Linerboard Furnish" (1990). Paper Engineering Senior Theses. 197.