CNF may boost strength of packaging papers
The use of bio-based cellulose nanofibrils (CNF) offers potential benefits for the production of both conventional and new paper grades, according to a technical paper authored by experts from GL&V and the University of Maine. The paper, The Application of CNF to Improve Packaging Grade Performance, was presented at PaperWeek Canada in February.
By Cindy Macdonald
GL&V and the University of Maine have formed a product development and commercialization partnership for CNF technology, called FibreFine™.
Several trials were run on different paper grades on the UMaine pilot paper machine, with CNF added both to the furnish and as a surface application on the fourdrinier table. Results for an OCC packaging grade are very encouraging, say the authors.
Comparing the two methods of incorporating CNF, the authors noted that adding CNF to the furnish demonstrated the maximum strength improvement, and improved internal bond strength.
A drop in freeness causes 1.5-2.0 per cent drop in couch solids, but press dryness may rise, they state.
Applying CNF to the surface gives a smaller strength improvement, a large decrease in porosity and an improvement in sheet smoothness. The small volume of secondary flow does not affect couch dryness, according to the authors.