Improving the extensibility, wet web and dry strength of paper by addition of agar

High extensibility of paper is of great importance for many finishing and converting operations. Extensibility is a key feature for the paper and paperboard which are utilized in production of advanced 3D-shapes. However, extensibility of the conventional paper and paperboard is usually quite low, but it can be improved by modification of fibre structure, fibre bonding and paper structure. In this article, spray application of agar on wet paper sheets was used for the improvement of the extensibility of paper. It was found that also other mechanical and functional properties such as wet web strength, air permeability and grease barrier can also be improved by agar addition. Extensibility of unrestrained dried paper was increased by 4%-points. Further, paper treated with agar exhibited an excellent performance in the preparation of the 3D-shapes