the mid 1990s and have become firmly
established as the high quality products
of choice for the global paper market.
The principal strengths of these products
lie in the raw material itself. "Natural
engineering" delivers a combination of
high brightness, narrow particle size
distribution and low abrasion which
cannot be matched from other global
reserves.
portfolio and is produced largely from
a reject stream which would otherwise
go into the impound or into lower value
filler grades. Low energy dewatering
using tube presses is also a key part of
CapimTM RG production, giving the
product a relatively low carbon footprint
compared to finer spray dried grades.
higher in aspect ratio (plate diameter)
than conventional Brazilian kaolins.
This combination is unique in our
product line and gives us a strong
offering to target applications where
coverage of the basesheet is critical in
governing the finished properties of the
coated paper. These include paper
grades used in rotogravure printing and
more demanding precoating applications
where the underlying basestock can be
very rough; for example in some board
and packaging grades. CapimTM RG is
also used effectively in low gloss, matt
paper grades.
around 20% of the total coated
mechanical market with over 2 million
tonnes production. The main end use
for rotogravure printing is high
circulation magazines and catalogues.
is centred on pigment concepts which
deliver the coverage and smoothness
needed for good rotogravure printability.
As a result, talc and high shape kaolins
are used extensively and carbonate
only in limited volumes. Now, however,
market pressures for cost and quality
are forcing a change in formulation
practice. Higher brightness is required
in the coated grades to compete with
the uncoated hi-brite supercalendered
(SC) grades, while at the same time it
is becoming important to maintain the
print quality and ink demand advantage
for the coated grades if premiums over
the SC papers are to be maintained.
Cost reduction is also needed if the
coated grades are to remain competitive
and this is prompting many producers
to look at reducing expensive talc usage.
carbonate which can be used in the
recipe and put more pressure on the
kaolin, not only to deliver coverage and
printability, but also optics. CapimTM
RG is perhaps the ideal kaolin for this
market situation. It can be used in
combinations with finer Brazilian grades
at heavier weights to deliver optics and
printability. At lighter weights it is effective
in partially replacing talc and lower
brightness rotogravure kaolins to deliver
paper brightness without compromising
printability.
both talc and finer rotogravure kaolins
effects printability in rotogravure as
measured by the percent missing dots.
The lower missing dots will give a
sharper more even image as more of
the applied ink has been successfully
transferred to the paper. In this case
CapimTM RG was able to replace all of the
finer clay and most of the talc without
causing a problem with printability.
However, it has to be remembered that
talc is also added for friction control
(resulting from its surface chemistry)
in the winding process so we would not
expect to replace all of it with CapimTM RG.
coverage in precoating when used
together with GCC. In general, coverage
can be better than with finer clays
such as CapimTM NP, but light scatter
and opacity are not as good so
CapimTM RG is probably best suited
to demanding applications on rough
basetocks where coverage is
paramount. The example below shows
the smoothness achieved in a wood
free precoating application. Lower
parker print surf values (PPS) indicate
a smoother sheet and better coverage.
the rotogravure, precoating and Matt
woodfree markets. Annual sales today
are already greater than 25kt and we
have numerous ongoing customer
projects which we hope will help
achieve in the region of 100kt sales
within 2-3 years.
and the rotogravure market please visit: