A1 Journal article (refereed), original research

Three-dimensional thermomechanical converting of CTMP substrates: effect of bio-based strengthening agents and new mineral filling concept

Open Access hybrid publication

Publication Details

Authors: Laukala Teija, Ovaska Sami-Seppo, Kerttula Ninja, Backfolk Kaj

Publisher: Springer Verlag (Germany)

Publication year: 2021

Language: English

Related journal or series: Cellulose

ISSN: 0969-0239

JUFO level of this publication: 2

Digital Object Identifier (DOI): http://dx.doi.org/10.1007/s10570-021-04139-4

Open Access: Open Access hybrid publication


The effects of bio-based strengthening agents and mineral filling
procedure on the 3D elongation of chemi-thermomechanical pulp (CTMP)
handsheets with and without mineral (PCC) filling have been
investigated. The 3D elongation was measured using a press-forming
machine equipped with a special converting tool. The strength of the
handsheets was altered using either cationic starch or microfibrillated
cellulose. Precipitated calcium carbonate (PCC) was added to the furnish
either as a slurry or by precipitation of nano-sized PCC onto and into
the CTMP fibre. The 3D elongation of unfilled sheets was increased by
the dry-strengthening agents, but no evidence on the theorised positive
effect of mineral fill on 3D elongation was seen in either filling
method. The performance of the strengthening agent depended on whether
the PCC was as slurry or as a precipitated PCC-CTMP. The starch was more
effective with PCC-CTMP than when the PCC was added directly as a
slurry to the furnish, whereas the opposite was observed with
microfibrillated cellulose. The 3D elongation correlated positively with
the tensile strength, bursting strength, tensile stiffness, elastic
modulus and bending stiffness, even when the sheet composition was
varied, but neither the strengthening agent nor the method of PCC
addition affected the 3D elongation beyond what was expectable based on
the tensile strength of the sheets. Finally, mechanisms affecting the
properties that correlated with the 3D elongation are discussed.

Last updated on 2021-21-10 at 12:16