2007年1月 紙パ技協誌

 
Creative Technologies of the Thermally Sprayed Coating, "KX ROCK", for Press Roll

Toshiro Tajiri, Nobuaki Sakoda and Susumu Arakawa
KURASHIKI BORING KIKO Co., Ltd.

 Recently, the requirement of high productivity in papermaking industry demands increasing the size and the running speed of papermaking machine, thus press-roll in the papermaking machine requires continuous improvement of the durability and stability.
 In the past years, the press-roll replaced drastically the natural granite stone in whole roll with an artificial ceramic coating in the surface only. This artificial ceramic coating in the surface requires not only good mechanical and chemical properties, such as resistance to wear and corrosion, but also surface properties, in which the condition of releasing paper off the roll surface, i.e. the draw property, and without contaminations attached are important.
 The "KX ROCK", which is ceramic coating by thermal spray for the press-roll, was developed as a replacement of the granite stone roll. The "KX ROCK" coating shows a superior draw property due to optimized surface roughness and wettability by the coating material. Especially, surface energy of the "KX ROCK" is higher than that of original stone roll, which leads to a good wettability, resulting in a better paper releasing property. And in addition, the "KX ROCK" also shows a good wear resistance and a perfect protection of base material from corrosion.


Retrofit of the Existing PS Screens by Unique Technology
- Dramatic Energy Saving and Performance Improvement -

Takeshi Kanazawa
Technical Department, Aikawa Iron Works Co., Ltd.

 One of the most familiar outward flow screens in Japan is a pressure screen that is called as PS-Screen. Using the latest screening technology developed by Aikawa, the performance of those screens can be dramatically improved; for instance, the specific unit power consumption can be reduced by 75% comparing with the original PS-Screen. This retrofit technology was conferred Sasaki prize on as the best development machinery of this year by Japan Tappi. This report introduces this technology.


Challenge to the Development of Bulky Paper in NPI

Takashi Ochi
Nippon Paper Industries Co., Ltd.

 Bulky paper is getting popular in the past ten years. If the thickness of paper is the same, the weight of bulky paper is lighter than conventional paper. This means that bulky paper is environmentally friendly because of the lower amount of pulps and other energy consumption, and is human friendly as well. Nippon Paper Industries Co., Ltd. (NPI) has been developing and producing bulky paper ranging from non-coated paper to coated grade by new technologies. These new bulking technologies are based on fillers and chemicals. These materials were not used for bulking paper in the past. NPI has challenged and succeeded to use these new technologies. Precipitated calcium carbonate (PCC) which has scalenohedral shape and appropriately controlled particle size is favorable for bulky paper. Those PCCs have been producing at mill-site plants of NPI. Chemicals for bulky paper (bulking agents) work as blocking hydrogen bonds of fibers and so cause the decrease of strength of paper. For this reason, paper makers have hesitated to use these chemicals. However, NPI has had conquered problems to use the bulking agents. With well designed filler and bulking agent and other novel technologies, up to 30% lighter wood free book grade can be obtained.


Quantitative Estimation of Macro Stickies in Recycled Pulps for Linerboard

Tadahira Yaguchi
Pulp & Paper Laboratory, Nippon Daishowa Paperboard Co., Ltd.

 It was difficult to separate macro stickies efficiently from recycled pulp for linerboard which consists mainly of old corrugated container and measure them accurately by image analysis method, because the pulp contains much flakes, shives and nonsticky foreign substances besides them.
 We improved the image analysis method of measuring macro stickies content, ISO 15360-2, to apply it to the pulp. By the improved method, macro stikies content in the pulp in treatment process was measured and the effect of removal and dispersion of macro stickies with equipments for screening and dispersing was estimated.


Inhibition of Yellowing of ECF Bleached Hardwood Kraft Pulp

Ayano Kawae and Yosuke Uchida
Research Development Div., Pulp & Paper Research Laboratory, Oji Paper Co., Ltd.

 The aim of this work was to inhibit the heat- and moisture- induced yellowing of ECF bleached hard wood kraft pulp (LBKP) in acidic paper. We have already reported that one of the derivatives of hexenuronic acid (HexA) in LBKP, 5-formyl-2-furancarboxylic acid (FFA), causes yellowing, and that FFA might polymerize or react with pulp components to form new chromophoric groups1).
 In this study, it was shown that the carboxylic base of FFA interacts with that of glucuronic acid or galacturonic acid, resulting in strong yellowing. Therefore, it seems that preventing the reaction of carboxylic bases could be effective in suppressing this yellowing. We have discovered that polycarboxylic acids (for example, citric acid, tartaric acid, etc.) are useful as a yellowing inhibitor.


Excellent Printing Effect of High-quality Newsprint

Masayuki Kawasaki
Nippon Paper Industries Co., Ltd.

 High quality newsprint is characterized by neutralized paper manufacturing process and high addition of calcium carbonate. We have almost converted to the high quality newsprint from previous product in all mills of our company. We confirmed that operation aptitude for print like web break and dust level is as good as the previous product according to past market evaluation. On the other hand, print qualities of multi color printing such as show through, tone reproduction, color reproduction are highly evaluated compared with the previous product. It was considered that high addition of calcium carbonate that showed high light scattering as filler contributed to these print qualities of multi color printing.
 In this paper, characteristics and printability of the high quality newsprint are introduced, especially the analysis result of the mechanism that derives excellent print effect in multi color printing than the previous product is explained.


Operational Experience of New Winder Control System

Tetsuya Okouchi
Noumachi Mill, Chuetsu Pulp & Paper Co., Ltd.

 Usually, only position data are sent to the drive for stopping winder to remove spots on the paper. Stopping position of winder is not accurate by that way, because paper length changes on the process, web brake shortens paper length, and also the marking position is reversed on winder.
 New Winder Control System (NWCS) solved that problems, by adding position data on the mark, which is printed on the paper edge by ink jet printer. The data included in the mark are read by the camera on winder, and control signal based on the data are sent to the drive. The stopping position is very accurate, because the position data in the controller are always refreshed by the mark.
 This is really useful system, and will be quite popular system in near future.


Operational Experience of the Biomass Boiler

Yousuke Makita
Power Section Tokai Pulp & Paper Co., Ltd.

 Tokai Pulp Ltd sets up a mill at Shimada city located almost middle in Shizuoka prefecture. This Shimada Mill reaches 100th anniversary in next year and manufactures paper and pulp mainly. Much electric power and steam is necessary for the manufacturing process of paper & pulp. The necessary electric power was generated at its own power plants; a hydroelectric power plant and thermal power plants and it bought the shortage of it from Chubu Electric Power Co., so far. The steam was generated by its own some boilers; heavy oil fired boiler, soda recovery boiler and waste fired boiler, so far.
 We planed biomass boiler power plant in order to reduce a mount of exhaust CO2 and a cost of energy among the social trend to stop green house effect and to realize Society with an Environmentally-Sound Material Cycle. We started to construct No.11 Boiler/ No.5 steam turbine generation plant whose fuels are wood biomass and RPF at May in 2005, completed it at January in 2006. The introduction of this plant realized the conversion from fossil fuels to biomass fuels and can achieve the initial purpose.
In the report, we describe the outline of biomass boiler plant operated from February in 2006 and the operational experience.


Breeding Strategy for the Pulp Quality Improvement in Eucalyptus Trees

Shigeru Sato
Forestry Research Institute, Research & Development Division, Oji Paper Co. Ltd.

 The Eucalyptus species are widely distributed in the temperate zone in the southern hemisphere and used as a raw material of pulp in Asian-Oceania region. The paper manufacturing industry has particularly high expectations to this tree because it has superior growth property and pulp quality. Since 1991, Oji Paper has been advancing the overseas forest plantation business for securing the forest resource and to protect the environment.
 Forestry Research Institute of Oji Paper has been studying the improvement of the productivity of Eucalyptus plantation in Australia. We have already isolated a lots of plus tree candidates which were selected by growth characteristics (height, diameter, etc.) from several plantation sites. We carried out the wood quality analysis of the candidates. The results of the analysis showed that there were great differences of basic density and pulp yields among the candidates, and suggested that it is very important to improve not only growth but also wood quality for the plantation business and paper manufacturing. Therefore, we have been progressing the Eucalyptus breeding project to improve the wood quality of the candidates. Our breeding project has two approaches. One is the conventional breeding method and the another is the molecular breeding method using the regulatory genes of wood quality. We report our current status of the project.


The Approach for No Manual Sorting System

Hiromu Nakamura
Hokuetsu Kamiseisen Co., Ltd.

 A sheet finishing process is still underdeveloped compared to developed large scale and well controlled paper manufacturing process. Therefore, it needs many skilled employees who work on manual inspection and sorting. Hokuetsu Kamiseisen Co., Ltd. operates wrapping on rolls, sheeting and sheet finishing process in Hokuetsu Paper Mills, Ltd. Niigata Mill and has plugged away at labor-saving through not only automatic equipment but also awareness reform that called "quality verification activity between processes".
 This report is focused on the labor-saving history, especially "the quality verification activity" is described. This activity is extremely successful with the labor-saving and the re-inspection and resort worked by many skilled sorter are basically abolished.