Colour Chronicle - April 2012 - Clariant

Why use Cartabond ?
Consequences of a Weak Paper Surface
strength
Damaging Factors
Mechanical stress: rubbing forces on
rolls, pull of printing ink (printing nip),
high speed copies..
Moisture: in drying roll sections,
rewetting before calendering, fountain
water (offset printing)…
Physical Consequences
Free and weakly bonded fi ller particles /
fi bers / coated areas are easily pulled out
of the surface
dusting, linting, picking problems
uneven surface properties (smoothness,
gloss, adhesion, printability…
Operational consequences
Paper Processing: deposits on rolls (drying,
calendering) & coating defaults (uneven
coated layer)
Printing process: degraded printability and
print quality:
Offset: deposits on blanket (piling,
white spots due to picking, uneven print
quality, ink contamination, equipment
contamination (dust).
Offset Printing & Wet Picking
Water is absorbed on the hydrophilic areas
of the printing plate, ink on the hydrophobic
ones.
Ink and water are transferred from
the printing plate to the blanket and from
the blanket to the paper. The paper goes
through several presses to be printed by
each colour before drying.
Picking occurs when the ink fi lm is split
between the paper and the rubber blanket if
the paper is weakened by water addition on
the previous presses.
Growing needs for Wet Surface Strength
Upgrading
Increase of fi ller contents - Use of
PCC
Increased use of Recycled Fibers
Increase use of Eucalpytus, Bagasse
High-speet Photo copiers / Offset
Printers
Development of Newspapers Upgrading
(size press)
How does Cartabond work ?
Cartabond creates new bonds between
cellulosic fi bers, binder and pigment
particles at the paper surface. The
surface structure is more resistant:
dusting, picking and linting problems
can be signifi cantly reduced.
Cartabond TSI liquid decreases the
sensitivity to water of hydrophilic
binders, such as starch, proteins, CMC,
PVOH
Printing Ink
Next
Press
Picking Area
on Printing Nip
Fountain Water
Printing
Plater
Rubber
Blanker
paper title
– swelling of binder molecules is
considerably reduced.
– bonds between cellulosic fi bers and
pigment particiles are more resistant.
The Wet Surface Strength of Papers
and Boards is improved considerably.
This result in:
– Better Printability
– Reduced Deposits on operating
rolls in wet conditions (offset
printing, calendering.)
Paper
colour chronicle 2 | 2012 15