2005年4月 紙パ技協誌

[プリント用ページ]

Development of the System which Allows the Commercial Scale Plantation Using the Plus Trees of Eucalyptus globulus

Shunji Omori
Research Center, Mitsubishi Paper Mills Limited

 Eucalyptus globulus, a kind of eucalyptus, is well known as a commercially valuable species for plantation with its excellent growth rate and its high density. But clone plant production through cuttings have not been applied in commercial scale due to the difficulty of rooting from the cuttings and also due to the lack of the selected plus trees.
  Purpose of our study is to select the plus trees of Eucalyptus globulus and develop the system which allows the commercial scale plantation using the selected plus trees. In this paper we report our experience on the selection of the plus tree showing superiority in growth, density and others from the plantation area, propagation of clone plus trees having excellent growth rate and rooting capacity through cuttings, and plantation trial of the plus trees.
  As a result, plus trees showing more than 50 % higher volume growth rate and more than 10 % higher density were selected through the study and established cloning system which allows the commercial scale plantation of thus selected plus trees.


Hardwood Kraft Cooking and Bleaching
  ― Emphasis on Raw Material Variability and Hexenuronic Acid Formation and Removal―

Toru Kobayashi
Metso-SHI KK, Japan
Lars-Ake Lindstrom1and Maria Wennerstrom
Metso Paper Sundsvall AB, Sweden

  Recent years have seen a lot more research focusing on hardwood pulping and bleaching processes. Although the understanding of these processes and the importance of raw material variability have increased, it has become obvious that there is still more to learn. Yet, technology has evolved.
  It is possible to adapt cooking conditions for low Hexenuronic acid content of unbleached pulp, improving bleachability and decreasing brightness reversion. Today's modern light ECF bleach plants, utilising improved oxygen delignification technology and high consistency ozone bleaching, have made it possible to decrease effluent emissions in a cost efficient way, while maintaining pulp quality. Optionally, TCF bleaching is possible that would bring emissions to very low levels.


The Latest Screening Technology
  - Newly Developed Ultra Energy Saving Screens & New Theory of Screen-Plate Designed by Hydrodynamics -

Takeshi Kanazawa
Aikawa iron Works Co., Ltd.

 Screening performance has been dramatically improved by the development of bar type screen cylinder. Especially, this technology has contributed to improve sticky problems which is one of the most important subject for recycling fiber treatment and power saving in screening department. We, Aikawa, was awarded “Sasaki-Prize” by Japan Tappi for the “GranFlow-Screen” as the most superior development for the year of 2000. This paper reports the most recent technologies regarding to power saving of screening field that we have further developed since 2000.


High Density Pulp Bleaching with the Aikawa ConiDiscTM Disperser System

Shinichi Mano
Iwanuma Mill,
Nippon Paper Industries Co., Ltd.
Mitsuhiro Sugino
Technical & Engineering Div., Nippon Paper Industries Co., Ltd.

 The Nippon Paper Industries Iwanuma Mill has three newsprint paper machines. To increase the DIP rate of newsprint production, a new DIP process (DIP-3) was started up in July 2003. This process was given consideration to reduce sticky trouble at the paper machines. So we introduced the latest machines and new ideas.
  The Aikawa ConiDisc Disperser System is one of the new machines, which was introduced to the new line at this time. The Conidisc consists of a conical-zone and a disc-zone. Because of that shape, it has two characteristics both high-speed disc-disperser and low-speed kneader. Since DIP-3 started, we have gotten good operations out of the ConiDisc in sevaral phases. This paper mainly reports the DIP bleaching with the Conidisc and other effects of this machine.


A New Fixing Agent for Rosin Emulsion

Yuko Okusa
Kurita Water Industries Ltd.

 Anionic trashes or anionic interfering substances are released into the water phase from contaminated reused water, recycled fibre, or broke, and form deposits at papermaking process including the wet-end, press section, machine fabrics and rolls. The anionic trashes can cause loweing of productibity by defective products; sheet break, short shutdown duration. These kinds of troubles can be controlled by dosing cationic coagulant.
 On the other hand, papermaking trouble is also deriving from the inadequated using of chemicals, such as poor fixing or over dosing of chemicals. These chemicals also behaviored as interfering substances when they enriched in the white water cycling loop.
 This paper focoused on the unfixed rosin sizing agent, and discussed the chemical charactors and behaviors of the rosin fixing agents by lab and field trials.


Effects of Pigment Shape on Paper Properties

Taro Homma and Takashi Kobayashi
IMERYS MINERALS JAPAN K.K.
Rajan R. Iyer
IMERYS Pigments for Paper Americas

  It is well known that the flat shape of kaolin particle contribute to paper/print gloss and opacity in coated paper. A flatter (high aspect ratio) particle gives improved coverage and smoother surface properties for coated paper. Print gloss will also improve from a coating structure using higher aspect ratio pigments. However to measure a pigment's aspect ratio is a time consuming procedure, so there seems to be few detailed studies of the correlation between the aspect ratio of a pigment and coated paper properties.
 This study aimed to research the effect of the pigment's aspect ratio on coated paper properties, especially in light weight coated paper in which the physical characteristics of pigments have a larger impact.


The Effect of Latex on Print Gloss

Eisuke Shiiyama
Latex Research Center,
NIPPON A & L INC.

  In recent years, the quality demands to the higher grades of coated paper have been extremely diversified, emphasizing on sheet gloss, print gloss, whiteness, opacity or low density, then so many new grades of coated paper were released to the market during the last few years. The emphasized "print gloss" grade beyond LWC especially made a major trend because print gloss has been thought the most important quality in the final printed products.
 It has been generally thought that "generation" and "leveling” of the split pattern of the printed ink is very influential to print gloss, and that the former ink behavior is mainly affected by printing pressure, speed and the amount of ink supplied to the coated surface, the latter ink behavior is greatly affected by the penetration speed of ink vehicle into coated layer. Moreover it has been experienced that the design of latex is very influential on print gloss.
  In this paper, we tried to explain the print gloss by the two types of ink behaviors, the primary and the secondary ink penetrations, with varying design of latices used in coated layer as the main binder. The primary ink behavior is defined by wetting of ink toward coated paper surface and the secondary one is defined by ink penetration into the coated layer. It was concluded that the primary one play a influential role to the print gloss, although the secondary one has been the most influential factor on print gloss so far. The primary ink penetration would become a very important key to improve print gloss further in future.


Structural Analysis of Coating Layer Containing Plastic Pigments

Yoko Saito, Hideki Touda and Junji Kasai
ZEON Corporation

 Recently, the amount of plastic pigment used for coated paper has been increasing because the requirement of coated paper has been changed to have high sheet gloss, high brightness, and good opacity. The effect of plastic pigments existing in coating layer on the properties of coated paper was investigated by analyzing the structure of coating layer.
 According to the results of the measurement of porosity, SEM image of cross-section surface and analysis of its photographic image, it is found that the coated paper including plastic pigment shows the excellent smoothness and has a lot of pore in the coating layer and the orientation of inorganic pigment are disordered compared with that formulated by inorganic pigment only.
  This tendency is stronger in case of using hollow sphere. Following 2 reasons were considered, the existence of void due to the hollow sphere itself and disordered orientation of inorganic pigment by hollow sphere which has large particle size. Plastic pigment would play an important role in order to manufacture the coated paper of bulky and excellent optical properties. In this report we describe these examination results.


Use of Paper Sludge Ash as Paper Filler and Pigment

Kimio Hiyoshi,
Shigeo Muramastu and Masato Saito
Fuji Industrial Research Institute of Shizuoka Prefecture

  Paper sludge (PS), which is exhausted in the conventional paper-recycling process, is mostly used as a raw material of cement at present. The application for the cement production is, however, not able to produce high additional value. Moreover, much amount of the other PS cannot be used for the above application due to the low quality, which results in the incineration to be buried under the ground.
  For getting more effective utilization of PS, we carried out a study on the reuse of PS as raw materials of paper. In this study, proper conditions for making fillers and pigments from PS, such as incineration temperature, atmosphere, time and etc., were determined, and the recycled paper was tentatively manufactured using these fillers and pigments. It was confirmed that the cost to make paper using PS-derived raw materials was cheaper than the cost to dispose PS and make paper using new raw materials.
  The PS recycled paper is now submitted to a feasibility examination to launch toward a commercial production by the collaboration with one enterprise.


Safety Standard of Machinery and Safety Components
  - A New Direction of the Safety Standards -

Tsuyoshi Matsumoto
Project Sales Department Safety Component Group OMRON Co., Ltd.

  In Japan, occupational safety at work has been based on "education to avoid danger" until now. However, this culture is now becoming difficult in front of the foreseeable social change, for instance, aging of skillful experienced worker, increase of part-time workers and alien workers with different language and culture. In this circumstance, it will be indispensable to shift the culture to the occupational safety based on safety design. Because worker may make a mistake and machine may break at anytime.
 For safety design of machine, it is practical to use safety components in accordance to international standards for safety such as ISO and IEC.


A Study of the Relationship between Coated Papers and Reverse-Image Ghosting

Kimito Washiya,
Yuichi Shiba and Tetsuya Nishi
Corporate Research Center, Mitsubishi Paper Mills Limited

  Reverse-image ghosting is one of the ink transfer errors that occurs during web-fed offset printing. It happens when the imaging area on the face and the back are not balanced. This paper report what properties of coated paper influence reverse-image ghosting. Reverse-image ghosting was not influenced by water absorptiveness, stiffness or picking intensity. However, smoothness had a comparatively strong relationship with ghosting. In particular, dynamic (PPS) roughness under 20 kgf/cm2 of hard backing was strongly related to it. And in the case of the same PPS roughness, ink receptivity was related to ghosting. These results support the idea that reverse-image ghosting is caused by improper web release of paper, which leads to ink piling on the blanket cylinder and ultimately to reverse-image ghosting.

Keywords: offset printing, ghosting, coated paper, delamination, reverse-image ghosting