Paper Technology International 2024 - Journal - Page 78
PAPERTECHNOLOGYINTERNATIONAL
Graph 3: Starch retention on a pilot paper machine using 100%
surface sized broke.
3. Replacement of Fibre with Filler
The most impactful economic bene昀椀t of using
cationic surface sizing starches is the ability to replace
昀椀bre with 昀椀llers and reduce total surface sizing starch
consumption. The low cationic starches present in the
internal broke support 昀椀ller retention, leading to an increase
in 昀椀ller levels. By reducing the dosage of fresh 昀椀ller,
mills can achieve certain cost savings. For instance, a
Scandinavian 昀椀ne paper mill saw a 1-2% increase in 昀椀ller
levels, allowing for a 5% reduction in fresh 昀椀ller usage,
resulting in signi昀椀cant material annual savings.
4. High Surface Strength and Additional Savings
It is proven that at a comparable viscosity level, a low
cationic starch tends to less sheet penetration when applied with
a size or 昀椀lm press compared to a non-ionic native starch. This
is again due to its interaction between the low cationic
charged starch with the anionic charged 昀椀bres at the
paper surface which maintains more starch onto the sheet
(Picture 1). This effects much higher surface strength
which enables the paper mill to reduce the surface sizing
starch consumption by ca. 30% without decrease in
surface strength.
The advantages of low cationic starches extend
beyond ef昀氀uent reduction, improved runnability, 昀椀ller
replacement and higher surface strength (Graph 4).
Their higher presence in the broke leads to improved
drainage, reduced re昀椀ning energy requirements, may lead
to increased production capacity, and potential savings
in retention aids, sizing agents, and dry strength agents
like wet-end starch. These additional savings contribute to
overall cost reduction and process optimization.
Graph 4: In昀氀uence of starch viscosity and ionicity on paper
surface strength.
Picture 1: Binary pictures from microtome section (white areas are starch;
starch distribution in Z-direction where the lines reveal starch intensity).
78
