Date of Award
Bachelor of Science
Paper Science and Engineering
Dr. Raja Aravamuthan
Recycle mills that use old corrugated cardboard (OCC) in their furnish experience difficulties in maintaining the quality of the paperboard produced. Recycle mills using the OCC collect their OCC from many parts of the world. Countries such as China and Japan use rice fibers in the production of corrugated cardboard. Other countries use straw as a fiber source. The end result is that OCC in the United States contains a portion of non-wood fibers as well as the typical wood fibers. Paperboard containing these non-wood fibers typically has lower strength properties than paperboard produced from pure wood fibers. Literature suggests that lignosulfonate compounds can be used as a strength agent for recycled wood fiber paperboards. Calcium lignosulfonate is readily available and is not costly and would prove to be an ideal strength agent for use in recycled paperboard. The objective of this project was to test calcium lignosulfonate as a strength agent in improving the runnability and strength properties on paperboard made from wheat straw paperboard and/or paperboard containing a mixture of wheat straw and wood fibers.
Handsheets (120g/m2 ) were prepared on a Noble and Wood handsheet machine. The handsheets from each furnish were then immersed in a bath of calcium lignosulfonate followed by an immersion in kymene. Calcium lignosulfonate levels were varied in the bath in order to control the amount of calcium lignosulfonate applied to each handsheet.
The results show that as far as recycled pulp is concerned, CaLS at 10% is definitely beneficial compared with no CaLS in all strength properties. In the case of straw paperboard, 10% CaLS definitely gives higher strength properties compared with no CaLS (except for burst and Scott bond). Higher CaLS levels (10% or 20%) may be justified only in the case of ring crush. As for mixed fiber paperboard, CaLS seems to yield better strength properties (except in the case of Scott bond and burst). While 10% CaLS still seems to be sufficient, 20% seems to result in better crushing resistance and stiffness. The conclusion of this project is that 10% CaLS yields better strength properties in most of the cases and can be the starting point for further refinement studies.
Martin, Francisco L., "Lignosulfonate as a Strength Additive for Non-Wood Paperboard" (2000). Paper Engineering Senior Theses. 293.