C☆iGum™ modified starches for high bonding performance, Ivo Baumann, Senior R&D Specialist at Cargill, Michael Stratemann, Senior Technical Account Manager at Cargill

PAPERTECHNOLOGYINTERNATIONAL
The glue formulations need to take this into account and
the glue batches are typically measured with higher cup viscosities
(Stein-Hall, Lory, Love, etc.), when compared to native adhesives.
C iGum™ products bring significant advantages in both
carrier and secondary starch functionality:
Carrier functionality: While in storage, a slightly higher
adhesive viscosity is preferred to avoid sedimentation of the granular
secondary starch and keeping it homogeneously distributed within
the liquid.
In the glue gap, a low viscosity is beneficial to improve film
dosage on the applicator role and to reduce hydrodynamic forces
to the doctor roll. This is an aspect that becomes increasingly
important the higher the corrugator speed gets and in cases where
glue gaps are running at minimum (see Graph 2 bottom left). At this
stage, it again becomes possible to control the amount of adhesive,
and hence water, which gets in contact with the board. In this way,
it ensures that there is always the right amount of glue available for
achieving the targeted bonding strength.
The short glue texture achieved with C iGum™ helps to
reduce the risk of splashing (see Picture 2 above) and a better
controlled adhesive positioning to the flute tips becomes possible. At
the same time, the glue can sufficiently penetrate into the paper to
secure a good anchoring of the starch.
Secondary starch functionality: Another aspect is the
gelatinization speed and glueing power of the secondary starch.
In a Stein-Hall adhesive, roughly 85-90% of the starch
is still in its granular form and only starts gelling when a defined
temperature is exceeded (gel-point temperature). At this point, it is
important that the viscosity ramps up fast enough to an elevated
level so that sufficient bonding force is created to pass the downstream slitter-scorer unit securely (see Graph 1).
When using C iGum™, the just gelled gluing lines are more
mature and rigid. This helps in avoiding common board defects like
delamination issues or glue deposits on the circular knives. The
board is ready earlier for further conversion without extended curing
time.
The starch solution for corrugators
Modified starches from both wheat and corn, represented by
Cargill’s C iGum™ corrugated portfolio, can help take corrugators
to a high performance level, without adding further process
complexity to the adhesive preparation processes, and without
compromising on machine efficiency or board quality.
Glues made with C iGum™ have more glueing power, as
well as being more dynamic, responsive and easily controllable on
the flute tips. This avoids excessive glue usage and helps to improve
board flatness already at the stacker.
The rapid and strong heat response makes these solutions
attractive for fast running corrugators. This is not only the case
for single wall board but also for double and triple wall machines,
running with heavy and Kraft papers.
Moreover, costly starches or additives can be avoided and
simplified glue recipes can be obtained. This allows the corrugator
to produce at the highest level of efficiency and maximum output,
reaching better quality while reducing drying energy and glue
consumption.
Visit our website Corrugated | Paper & Board | Bioindustrial |
Cargill to learn more and connect with our experts.
105

Paperturn flipbook viewer