2009年11月 紙パ技協誌
 
2009 November JAPAN TAPPI JOURNAL


Vol.63 No.11 Abstracts


Paper and Environmental Consideration
-Consideration for Environmental Load Reduction of the Society-

Kazuhiro Hashimoto
Environment and Economy Division, Environmental Policy Bureau , Ministry of the Environment

 There are various viewpoints for the environmental consideration of paper production and usage. One is the viewpoint from the side of paper companies, and another is from the environmental policy. When information on these viewpoints is adequately disclosed to consumers, the market will shift toward green production. This is why appropriate environmental communication to consumers is extremely important.
 This report introduces a new method of bringing change into the market by Green Purchasing Law.


Newest Modification for Existing Twin Wire Former

Masahito Mukai
Kobayashi Engineering Works, Ltd.

  This paper examines two top-wire forming units from a fundamental standpoint, one a roll type top unit while the second is a bladed top unit. Both units are located an identical distance from the headbox and use the same furnish. The fundamental dewatering mechanisms are examined for both the roll type and blade type formers. Both configurations are numerically modeled to evaluate differences in the pressure fields, estimated pressure gradients, and shear between the wires.
  The roll type top unit demonstrates constant pressure forming and the characteristics of high drainage velocity under low shear. By contrast, the bladed type former demonstrates web forming brought about by variable, increasing pressure pulses at locations on the former where the wet web is subjected to multiple shear conditions. The effect of these different mechanisms is explored relative to final sheet properties that were measured on representative paper samples taken before and after conversion of the newsprint machine from the top-wire roll to the top-wire blade unit.


Operating Experience of Mini Shoe Press on PM2

Daisuke Taguchi
Hachinohe Mill, Mitsubishi Paper Mills Limited

  Hachinohe Mill, Mitsubishi Paper has the capacity of approximately 900,000 ton of papers per year. We have seven paper machines in Hachinohe Mill, and installed Mini shoe press of MHI in No.2 (2PM) and No.6 (6PM) paper machines with the aim of steam saving and production increase in August 2007. Mini shoe press is compact type of shoe press covering some faults of standard shoe press, and has high dewatering performance. This remodeling brought dryness up, speed up and higher machine efficiency, and we achieved the aim of steam saving and production increase.
  This report is described about the outline of remodeling and the effect of Mini shoe press at 2PM.


Paper Quality Improvements of Kraft Paper by Installing Breast Roll Shaking System: Form Master

Tsuyoshi Hama
Takaoka Mill Nohmachi, Chuetsu Pulp & Paper Co., Ltd.

  Takaoka Mill Nohmachi started the operation in 1949 as Sulfite Pulp Mill. Then started up paper machines after 1956. Currently, it is an integrated mill focusing on coated paper and also producing other grade such as fine paper, kraft paper, white wrapping paper.
  No.3 Paper Machine started the operation of unbleached kraft paper since 1968. At present, No.3 Paper Machine manufactures. heavy wrapping paper, light wrapping paper and bleached kraft paper etc. In order to improve those qualities, we introduced high speed wire shaking equipment (Form Master manufactured by Metso Paper). I would like to report on the operational experience of this wire shaking equipment and also on the paper quality improvement result of kraft paper by the introduction of this equipment


Manufacturing Process and Proper Way to Operate of Forming Fabric

Yutaka Shibahata, Tatsuhiko Yasuoka and Akinori Sano
Technical Service Dept., Nippon Filcon Co., Ltd.1

   Improvements of paper quality and productivity have been accomplished by wider manufacturing width and higher speed paper machines, such as advanced model or modified paper machine as represented as Gap Formers as their counter plan in the pulp and paper making industry for external environmental issues, like raising raw material cost or various and high quality requirements from customers. Forming fabric designs have been developed from single layer fabric to triple or triple weft (3.5 layer fabrics) fabrics which allow various purposes with respected results along with the improvement of paper machines. As a behind scene of those improvements, surely there are three major operation technologies make forming fabrics capabilities as their ultimate level, proper application of forming fabric specifications to meet requirements of paper machines, establishment of high-tech manufacturing processes of forming fabrics having various purposes and optimize fabric runnability to maximize paper machine efficiency.
   Let us focus on these three major points of forming fabric above to evaluate forming fabrics in general as follows.


Basic Design Concept of Paper Machine Clothing for Press Part

Hirofumi Ishii
Technical Department, Ichikawa Co., Ltd.

   As a specialist of Paper Making Machine's press part, Ichikawa has been supplying Press Felts, Shoe Press Belts, Transfer Belts and Cleaning Detergent since its foundation. Press Part of Paper Making Machine has been changing from Roll-press to Shoe-press type and complete No-Open-Draw sheet running configuration is recently becoming popular with getting higher Machine speed up to 2,000 mpm and wider Machine width up to 11,300mm. In order to meet such severe condition, Machine Clothing is also developed of their quality and function, and has succeeded to improve them indeed.
   In this paper we attempt to explain our fundamental design concepts and applications in designing of each clothing for highly-developed Paper Making Machine's demand.


Energy Savings by Grooved Belt for Shoe Press

Satoru Nakazato
Saga Mill, Oji Paperboard Co., Ltd.

  In 1997, a shoe press was installed at the third press of PM1 at Saga Mill as part of a project to increase production capacity. The first belts installed after the rebuild were plain type belts. In October 2000, with the aim of improving dewatering capacity, we tested a grooved belt (250cc/m2).   However, the result was inconclusive, and there was a further question of cost, so we continued running only plain belts. However, while there are many possible explanations, we had the idea that maybe increasing the void volume and increasing the volume of nip splash would be beneficial to dewatering, and from June 2005 we recommenced a trial of a grooved belt (manufactured by Albany, 400cc/m2).
  The results were good. Steam flow was reduced, and unit steam consumption was improved by 15%. Further, we were also able to reduce electricity consumption by stopping the felt roots blower.
   When recommencing the use of grooved belts, we started from a fabric having a void volume of 400cc/m2. We are currently using fabrics having 450 to 470cc/m2 and machine operation is good. For the future, we do not plan to be simply content with this improvement, but intend to continue considering, and testing, belt and felt specifications to determine the very best combination in order to obtain further energy savings and higher efficiencies.


Operating Experience of the Top Wire Former

Koichiro Hayashida
Ashikaga Mill, Nippon Daishowa Paperboard Co., Ltd.

  In a recent, the quality of high speed corrugating board manufacturing has become higher for medium paper. The formation of medium paper which is made by No.3 paper machine in Ashikaga mill was worse than the other machines, and especially the crack of corrugated board had been occurred by the flock formation. So, for the problem solving, we decided to install the top wire former to get good formation and better properties, lower cost. And also, as there was no refiner in the secondary fiber process, it was no effective to defiber. And the quality of the surface layer was influenced by it. So the flow of the secondary fiber process was modified and we also installed a refiner in the reject part of the secondary fiber process on the same time when we installed the top wire former.
   In this paper, we report of the operating experience which installed the top wire former in January 2007 and the effect of getting good formation after the modification of the former in Ashikaga mill PM3, Nippon Daishowa Paperboard Co., Ltd.


Operating Experience of PM N1

Yukihiro Yamada
Tomioka Mill, Oji Paper Co., Ltd.

  PM N1, which is the All-Online-Concept paper machine, has been built in Tomioka mill. There are two main purposes to build the machine. One is to increase productivity of the LWC which has the growth market; another is to enhance global competitiveness at this market. We have started the trial operation of the machine at the beginning of November 2008, and then the commercial operation successfully since the February 2009.
  During the short operation period, which is still half a year, we have some troubles (two-sidedness, fiber ball and wad burn) at the wet section. This report presents the outline of equipment and latest operation experiences (especially these troubles) at the wet section of PM N1.


The Latest Print Technology Trend

Hiroshi Ushida
Toppan Printing Co., Ltd.

   People began to use the printing technique to transmit information in about the eighth century. The people came to consume printed matter in large quantities in the 20th century. The printing technique has continued to grow up and to prosper for a long term. The information transmission means was replacing of the information terminal recently. However, the technology related to the print is actually applied to the processing technology of an electronic equipment.
  Moreover, there is no state-of-the-art licensing-in as a printing technique in recent years. However, the technology of inkjet that digests in the market might take the place of a current printing technique. It is thought that it comes to a big transition stage now. The print technology is summarized as assumption of this text.


A Report on PaperCon’09 Conference & Exhibition
-May 31 - June 3, 2009 at St. Louis, USA-

Kunitaka Toyofuku
JAPAN TAPPI

   PaperCon ’09 Conference & Exhibition was held in St. Louis, Missouri, USA on May 31 - June 3, hosted by TAPPI.
PaperCon seems to be our annual meeting for TAPPI. It was co-hosted by PIMA (Paper Industry Managing Association) with various reasons from this year. Originally JAPAN TAPPI becomes the constitution including both. The exhibition is attached to the conference. Before and after the conference, I visited a mill of bio ethanol which is made from corn and North Carolina University.


A Report on 104th Zellcheming Annual Meeting & Expo
-June 23-25, 2009 at Wiesbaden, Germany-

Kunitaka Toyofuku
JAPAN TAPPI

  104th Zellcheming Annual Meeting & Expo was held in Wiesbaden, Germany on June 23-25, 2009 hosted by Zellcheming (The German Pulp and Paper Chemists and Engineers Association).
  Germany is originally an advanced country in the paper manufacture. Annual Meeting is performed every year at the same place in the same time. 1500-2000 people participated in the meeting from the European countries. I would like to emphasize the exhibition is large in scale. Although it was under bad economy, it was successful. 280 exhibitions were performed in the 4,300m2 area.
  Before and after the meeting, I visited Voith Research Center and paper mills in Germany.


Dynamic Mechanical Properties of Paper Containing a Polyacrylamide Dry Strength Resin
-Effects of Type of the Resin and the Application Method-

Takushi Sakaemura
R&D Department, Paper Chemical Division, Arakawa Chemical Industries, Ltd.
Graduate School of Agriculture, Kyoto University
Tatsuo Yamauch
Graduate School of Agriculture, Kyoto University

   Laboratory handsheets made from lightly beaten hardwood kraft pulp containing various amounts of polyacrylamide (PAM) dry strength resin were prepared by both internal and external application methods. The PAMs employed were a cationic PAM in solution and an amphoteric PAM in solution or the dispersion. The internal application was performed by adding the dilute PAM solutions or dispersion to the beaten pulp fiber suspension, while the external application was conducted by dipping a dry paper (handsheet made from the beaten pulp) into the PAM solutions or the dispersion and further squeezing them out with the standard wet press. Attenuated total reflection/Fourier transform infrared analysis combined with a gradual etching method was used to examine the depth profiles of the PAMs within a fiber wall. Both of the PAMs existed mainly near the fiber surface and further were distributed within the fiber wall. The amphoteric PAM by the internal application method was particularly distributed nearer to the fiber surface, comparing with the cationic PAM. Dynamic mechanical properties of the papers with or without PAM and the PAM films were measured at temperatures ranging from 140 to 260oC. With a help of the differential scanning calorimetry measurement, viscoelastic behavior of the PAM added to papers by the external application method was assigned to glass transition of the added PAM, typically shown in tan as the clear peak at about 210oC. In the case of addition of the solution or the dispersion by the internal application method, both cationic and amphoteric PAMs were distributed in molecularly dispersed state within a fiber wall, because viscoelasticity of the PAMs within a fiber wall almost disappeared. On the other hand, the external application method at the nearly same retention level of PAM gave the characteristic viscoelasticity, suggesting that the PAMs were distributed not in molecularly dispersed but forming a kind of PAM phase (domain). Comparing with the addition of the solution, the addition of the amphoteric PAM dispersion induced a more remarkable formation of the PAM phase and led to the pronounced appearance of the viscoelasticity of the PAM.

Keywords: distribution, dry strength resin, external application, internal application, polyacrylamide, mechanical properties, viscoelastic properties, paper


Investigation into the Cause of Print Mottle in Halftone Dots of Coated Paper: Effect of Optical Dot Gain Non-uniformity

Masayuki Kawasaki
Planning and Administration Department, Research & Development Division
Nippon Paper Industries Co., Ltd.
Masaya Ishisaki and Takashi Yoshimoto
Pulp and Paper Research Laboratory, Research & Development Division
Nippon Paper Industries Co., Ltd.

  One of the printing problems on print quality is non-uniformity of printing density called print mottle. It is known that printing conditions like ink and fountain solution amount, printing pressure and etc. affect print mottle. As far as paper, it has been thought that non-uniformity of ink transfer due to surface roughness of paper, absorption of ink and fountain solution, thickness causes print mottle. When we investigated on print mottle of commercial coated papers, most samples were explained with ink transfer, however we found that print mottle of some samples were inferior nevertheless their non-uniformity of ink transfer were small. The purpose of this research is to clarify the cause affecting print mottle in halftone dots except ink transfer in order to improve the paper quality moreover.
  First, we compared the light part and dark part of print mottle precisely using optical microscope. It is known that apparent dot gain (optical dot gain) arises in halftone dots due to light diffusion in the in-plane direction of paper, and optical dot gain also affects printing density as well as mechanical dot gain. We investigated the non-uniformity of light diffusion in the in-plane direction by means of micro-density profile of printed ruled lines. We also examined relationships between the non-uniformity of print mottle, light diffusion in the in-plane direction and coating color coverage on base paper quantitatively by using non-uniformity index.
   As results, non-uniformity of optical dot gain was concluded to be one of the important factors affecting print mottle in halftone dots. We found that the non-uniformity of optical dot gain was caused by that of light diffusion in the in-plane direction. Some of the causes of non-uniformity of the light diffusion were thought to be unevenness of coating color coverage on base paper, and difference of light diffusion between coating color and pulp fiber of base paper. It was thought that minimizing the unevenness of coating color coverage on base paper is quite important for controlling optical dot gain as well as ink transfer.

Keywords:print mottle, printing density, non-uniformity, ink transfer, optical dot gain, light diffusion, in-plane direction, coating color coverage