|Review of Paper Coating Technologies
Pulp and Paper Research Laboratory, R&D Division, Nippon Paper
Industries Co., Ltd.
Production of coated paper has been increased since it was invented,
and efficient production has been also pursued by means of increasing
speed, widening wire of paper making machines and etc. From the point
of view of economy and saving natural resources, coat weight and
basis weight are required to be decreased without lowering coated
paper quality. Paper coating technologies including coating methods
and materials have been evolved to meet these demands.
Recent Trends on Coating Color and Its Latex
Polymer Research Laboratories, JSR Corporation
Recent trends and information on coating color and its latex are
described. They are investigated into cost reduction, quality improvement
and productivity improvement. On cost reduction, increasing content
of calcium carbonate and reducing the binder content are proceeding
by using improved latex. On quality improvement, brightness, paper
gloss and printing gloss is improved. For the improvement, contents
of fine kaolin, fine calcium carbonate and fluorescent dye are
increased and plastic pigment or latex giving hard ink set-off
is used. On productivity improvement, coating speed and coating
solids content are increased. Increasing content of calcium carbonate
and reducing content of starch are advanced. And it is required
for latex to be non-adhesive and have good fluidity.
Under these trends, following two kinds of latex are wanted. One
is latex which gives stronger pick resistance and better runnability.
Another is latex which gives better printing gloss. The improvement
of the former has been advanced by small particle size and control
of particle morphology, molecular weight and cross-linking of polymer.
The latter has been improved by polymerization method of acrylonitrile
and control of particle morphology.
Recent Coating Color Preparation System
Metso-SHI Co., Ltd.
Metso's equipments for coating color preparation covers the
material receiving equipments to the surroundings of coater
heads. Especially, in this paper, modern coating color preparation
processes, which enable cost effective and environment-friendly
production as well as the production with excellent quality,
For color preparation, batch type methods are usually well-known and widely
Here, newly developed continuous method (GradeMatic), pressure screen (OptiScreen)
in color supply system, deaeration equipment (OptiAir), on-line color measurement
system (ColorMat), etc., are described. In addition, coating color recovery system
(OptiCycle) is described.
The Latest Technology and Trends in Coating Pigments
Pigments for Paper, Imerys Minerals Ltd.
Paper and paperboard coatings have become increasingly more sophisticated
in order to meet the advertising world's need for better visual
image. This together with machinery advances has driven significant
pigment developments over the past 20-30 years. For the most part
development has proceeded at an evolutionary rather than revolutionary
rate, but in the past 10 years we have seen marked increase in
the rate of new pigment developments and a dramatic reduction in
the shelf-life of existing pigments.
However, there are now signs that the paper industry is changing
in response to ever increasing cost pressures and at best flat
paper pricing. Although going forward we are still projecting significant
growth in printing and writing paper grades and a consequential
increase in pigment demand especially carbonates, it is likely
that the way in which pigments, especially high value pigments,
are developed and used will change.
The focus now is very much on how pigments can be used as part
of an application concept to offer value to the paper maker. New
pigments are increasingly being developed to work concurrently
with other pigments in multi-pigment application concepts. Understanding
how pigments influence coating structure in multi-pigment systems
is essential if performance and value are to be maximized and it
is clear that there are synergies there to be exploited. Most notably
it is apparent that the combination of platey kaolins with engineered
carbonates is a powerful tool for the paper maker to either adjust
quality or generate value through reduction of basis weight or
replacement of expensive opacifiers or glossing additives.
Operating Experience : No.1 Coating Machine at Ishinomaki Mill
Ishinomaki Mill, Nippon Paper Industries Co., Ltd.
No.1 coater machine in Ishinomaki mill has started producing coated
paper since 1981 as an off-machine coater. Currently it produces
330 ton per day off-set printing paper and gravure paper.
No.1 coater machine runs with very high efficiency and has achieved 97.3%, the
top rating efficiency among the all off-machine coaters in Nippon paper.
This paper reports the No.1 coater machine operating experience, including the
rebuild recently conducted.
GelView Sensor to Optimize the Coater Drying System
Pulp & Paper HPS, Honeywell Japan Inc.
Honeywell developed the new sensor technologies of the measurement
and control, which will be applied for the area from wet part to
dry end. These technologies have been launched from the last year
in Japan. The GelView is the one of these new technologies and
focusing on the coater part. The GelView provides the solution
for measuring the coating consolidation throughout the drying process
and can offer monitoring the coating consolidation progress and
profiles that could not be expressed by any sensors before.
The solution of the binder migration etc. that is the problem
of coated paper and the improvement and the stabilization of the
can be attempted by this technology. Moreover, it comes to lead
to an appropriate reduction in dry energy by the control or the
production increase of the product.
The contribution to a new paper manufacture technology by this
technology can be expected.
Operating Experience : No.5 Coating Machine at Hachinohe Mill
Hachinohe Mill, Mitsubishi Paper Mills Limited
Hachinohe mill established since 1966 has five coaters and two
of them are on-machine coaters. No.5 blade coater has been operated
since 1988 and the fastest actual operating is 1,575 m/min. It
produces about 650 ton of coated paper per day.
In this report we refer to three operative and technical problems
and solutions to archive faster operation of No.5 coater.
1)Technology of splicing wide rolls on high speed operating
2)Material and dimensional optimization of blade
3)Renewal of quality monitoring and controlling system
Furthermore two new technical topics are introduced.
4)Development of process technology for 2,000 m/min operation
5)Application of CFD (Computational Fluid Dynamics) to coating process
Influence by Coating Blade on Coating Machine Operation
Asia Marketing, BTG Eclepens S.A.
BTG Div. Spectris Co., Ltd.
Due to machine speed-up, coating with blade became the most popular
coating operation in the last decade. Position of the blade tip
in contact with paper & coating color determine the final coated
paper surface quality and also machine runnability. The determination
of the right settings, blade tip material and blade design is the
key of success. The advantages of using High Performance blade
are a slow wear of the blade tip, that allows keeping blade tip
shape constant and then to stabilize coater conditions, to enhance
coated surface quality in using material that perfectly fit coating
color peculiarity. Determination of the right mode of running (bent
or stiff), the proper blade tip material and blade characteristic,
and the optimized blade holder settings provide stability in both
quality and productivity.
Operating Experience: PM8 On-machine Coating at Niigata Mill
Niigata Mill, Hokuetsu Paper Mills, Ltd.
PM8 in Niigata mill has been in operation since 1998, and this
machine has the biggest productivity of coated paper in all our
In December 2001, the third-press was remodeled into shoe-press.
As a result, the productivity was improved significantly.
In this report, I would like to introduce the outline of the on-line coater
and the latest experience of the operation.
A report on International Paper and Coating Chemistry Symposium
Nippon Paper Industries Co., Ltd.
National Printing Bureau
International Paper and Coating Chemistry Symposium (PCCS) 2006
was held in Stockholm during June 7th to 9th, 2006 under co-organization
of KTH, STFI and YKI. PCCS dealt with fundamental and practical
researches on wet-end and coating chemistry. The number of participants
was around 220 including 22 delegates from Japan. The programs
had 10 sessions featuring 90 oral presentations including 19
invited lectures and 17 poster presentations. Trends of presentations
were summarized and notable researches were cited in this report.
The Development of New Extensible Paper for Heavy Duty Sack that
Helps Material Saving
Product Laboratory, Nippon Paper Industries, Co., Ltd.
Communication & Industrial Paper Sales Div., Nippon Paper Industries,
Asahikawa mill, Nippon Paper Industries, Co., Ltd.
Nippon Seitai Co., Ltd.
Multi wall kraft paper sacks used to have more than two layers
to prevent from break. Recently the layers of the paper sacks and
the basis weight of the kraft paper have been reduced to minimize
the cost and the material. However, the strength of the paper sacks
has come to the lower limit because of the reduction. For the further
material saving, the stronger and tougher sack paper with the same
amount of material is needed. Nippon Seitai and Nippon Paper Industries
have developed the new extensible paper suitable for multi wall
paper sacks. The elongation of the extensible paper is much higher
than that of the normal kraft paper and the ordinary extensible
paper 'Clupak'. It is found out that the new extensible paper is
much tougher to break because it absorbs the impact of dropping
or thrusting by stretching. Also as the new extensible paper is
made of 100% soft wood kraft pulp and the wood is mostly from the
periodic thinning, it is recyclable and environmental friendly.
In this paper, we would like to show the significant characteristics
of the newly developed extensible paper, and the material saving
example of multi wall kraft paper sacks by using the extensible
Keywords: Extensible paper, Material saving, Multi wall kraft
paper sack, Elongation, Recyclable, Periodic thinning