2006年12月 紙パ技協誌

[プリント用ページ]
Review of Paper Coating Technologies

Koji Okomori
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

Hisashi Matsui
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

Hidehiko Yamazaki
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, are introduced.
 For color preparation, batch type methods are usually well-known and widely used. 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

Chris Nutbeem
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

Toshihiko Nishikawa
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

Junichi Masuda
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 quality 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

Masato Shiraishi
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

Jerome Michaut
Asia Marketing, BTG Eclepens S.A.
Takuya Maekwa
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

Kazuhiro Takasumi
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 mills.
 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 part and the latest experience of the operation.


A report on International Paper and Coating Chemistry Symposium 2006

Shisei Goto
Nippon Paper Industries Co., Ltd.
Hitomi Hamada
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

Kiyoshi Saitaka
Product Laboratory, Nippon Paper Industries, Co., Ltd.
Nobuhiro Hatoh
Communication & Industrial Paper Sales Div., Nippon Paper Industries, Co., Ltd.
Hideichi Kawasaki
Asahikawa mill, Nippon Paper Industries, Co., Ltd.
Toshimi Satake
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 paper.

Keywords: Extensible paper, Material saving, Multi wall kraft paper sack, Elongation, Recyclable,           Periodic thinning