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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korea Technical Association of The Pulp and Paper Industry
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Journal DOI :
Korea Technical Association of the Pulp and Paper Industry
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Volume & Issues
Volume 32, Issue 5 - Dec 2000
Volume 32, Issue 4 - Dec 2000
Volume 32, Issue 3 - Sep 2000
Volume 32, Issue 2 - Jun 2000
Volume 32, Issue 1 - Apr 2000
Selecting the target year
Alkaline Sizing of Mechanical Pulp
Kim, Bong-Yong ; Akira Isogai ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 1~7
Alkaline Sizing behavior and mechanism of handsheets, which were prepared from thermomechanical pulp (TMP) with alkylketene dimer (AKD), were studied in terms of the conditions of the handsheet-making. AKD content in the TMP handsheets was increased with increasing of AKD addition level and the addition of a polyamideamine-epichlorohydrin resin (PAE) clearly enhanced AKD retention as well as the resultant sizing performance of TMP handsheets. Although drying of the AKD sized TMP webs at
led to no or quite low sizing level, but TMP handsheets sized with AKD had higher sizing degrees with increasing of the temperature of heat treatment. Scanning electron microscopic observations of the AKD-sized TMP handsheets showed that AKD emulsion particles were present on pulp fiber surfaces independently without coagulation in the TMP handsheets dried at
. Heat treatment of the AKD-sized handsheets resulted in disappearance of the AKD emulsion particles because of their melting and spreading. The addition of calcium carbonate filler to the TMP suspensions did not influence on AKD content in the TMP handsheets. Nevertheless, their sizing degrees clearly increased by the addition of
filler. Probably, AKD molecules adsorbed on the
filler particles contribute to the enhancement of sizing performance. Thus, AKD can give sizing features effectively to the TMP handsheets, when they are made under suitable conditions.
Quantification of Crystallinity Change in Celluloses during Refining
Kim, Chul-Hwan ; Yang, Jae-Kyung ; Park, Jong-Yawl ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 8~13
X-ray diffraction technique was used to quantify change of cellulose crystallinity during refining. XRD data confirmed that fiber wall delamination was caused by the structural conversion of celluloses which occurred in a liquid medium during refining. The quantified crystallinity of celluloses in pulp fibers was closely associated with the change of fiber wall delamination, which was defined by measurement of fiber wall thickness. In particular, it was well recognized that low intensity beating showed a better response in the change of crystallinity than high intensity one. The decrease o cellulose crystallinity during refining considerably enhanced the improvement of interfiber bonding ability of a dried sheet.
Characterization of the Spatial Variability of Paper Formation Using a Continuous Wavelet Transform
Keller, D.Steven ; Luner, Philip ; Pawlak, Joel J. ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 14~25
In this investigation, a wavelet transform analysis was used to decompose beta-radiographic formation images into spectral and spatial components. Conventional formation analysis may use spectral analysis, based on Fourier transformation or variance vs. zone size, to describe the grammage distribution of features such as flocs, streaks and mean fiber orientation. However, these methods have limited utility for the analysis of statistically stationary data sets where variance is not uniform with position, e.g. paper machine CD profiles (especially those that contain streaks). A continuous wavelet transform was used to analyze formation data arrays obtained from radiographic imaging of handsheets and cross machine paper samples. The response of the analytical method to grammage, floc size distribution, mean fiber orientation an sensitivity to feature localization were assessed. From wavelet analysis, the change in scale of grammage variation as a function of position was used to demonstrate regular and isolated differences in the formed structure.
A Review of the Topographical Causes of Gloss Variation and the Effect on Perceived Print Quality
MacGregor, Michael A. ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 26~43
It is well accepted that gloss variation deteriorates the print quality and there are various objective ways to measure this. Several studies now have shown that the coefficient of variation in the octave band passed printed gloss image has an excellent correlation with ratings by an expert panel using a magnitude estimation scaling method. The correlation improves when the gloss level is also taken into account beyond that of the COV. There is also evidence that the correlation would improve even more if the gloss spatial distribution could be better accounted for. We show that much (at least 80% and perhaps up to 90%) of the gloss distribution can be accounted for by the paper topography over a wide range of dimensions (scale). Recent work has supported the role that microroughness and multiple surface scattering play in the gloss distribution. This offers the promise of showing that even a greater amount of gloss variationcan be explained by topography.
The Role of Charge and Retention in Effective Wet End Management
Rantala, T. ; Nokelainen, J. ; Ojala, T. ; Sopenlehto, Taina ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 44~53
The development of paper machines, increasing machine speeds with new, mostly low basis weight and/or high ash content paper grades, as well as the fact that several trends regarding process items have increased the sensitivity of papermaking. At the same time, papermakers are looking for flexibility in the production line. We can say that with all PMs, the biggest benefits with the lowest capital spending can be achieved by focusing on improved wet end management. In order to manage wet end chemistry on a paper machine, our goal is to control subprocesses through which we can influence the operation of the entire wet end with maximum effect. Key measurements and controls are - white water consistency control which is the most effective way to control retention. - charge demand measurement and control which takes care of concentration of the anionic material entering to PM. - ash measurements and controls which are deeply related to retention and paper quality. This paper presents and concentrates to two of these key controls: retention and charge. The purpose of charge control is to give the process control the tools to react to changes caused by amount of dissolved and colloidal material incoming to wet end system. It is called coagulation or fixing control. Retention control is then taking care of retention aid flow to the process by responding any changes seen in white water consistency. It is called flocculation control. Each of these solutions separately, and even more effectively all together, stabilize the wet end operations and so greatly improve the produced paper quality and machine runnability. Practical results will be presented and they are referring to the latest mill cases. We have developed the first wet end measuring system in the late 1980s and control solutions based on this modern measuring technology were completely updated in 1990s. This paper introduces the principle, operation, and results of our unique wet end analyzers (retention and charge) which are at the level of automation solutions as a part of paper machine quality control. Especially our newest member of the platform, on-line charge analyzer has reached and set new standards to the on-line charge monitoring.
Next Generation Fiber Length Measurement
Tiikkaja, Esa ; Sopenlehto, Taina ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 54~59
The next generation fibre size analyser has been developed in Kajaani based on over 15 years experience in fibre measurement. This new FiberLab-analyser can measure fibre length both along the fibre centre line and as projected. The cross-sectional measurements of fibre are in principle similar to the earlier version FiberLab. Measured data are generally displayed in distributions. Some new calculations have been added, for example the fibres cross sectional area and fibre volume index both available as distributions as well. The performance of the FiberLab measurement is verified against the manual microscopic testing. These tests show that the new image analysis-based measurement well matches with the manual methods.
Coating Immobilization Using Soy Protein Polymers: Technical Concepts and Importance to Quality
Hiscock, Donald F. ; Merrifield, Thomas B. ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 60~66
Coating immobilization is the process by which the wet coating applied to paper or paperboard reaches the final form. A coating immobilization point is defined as the solids content reached during drying where no further redistribution of coating materials occurs. Good control of coating immobilization is important in producing coated paper and paperboard with consistent high quality. This paper discusses the technical concepts of how coatings immobilize, and describes the importance of good immobilization control on coating holdout and coating structure. The use of soy protein polymers to modify the coating immobilization point is discussed. Soy proteins, because of their interaction with coating pigments, make a significant contribution to the immobilization characteristics of coastings. This technology gives the formulator options for changing the immobilization point to improve the performance of the coating. The importance of immobilization on casting uniformity, microporosity and sheet qualities is discussed, including binder migration, mottle, gluing, and print quality.
The Future of Paper-Making: New Challenges for Technology
Karlsson, Markku ; Lindroos, Kaj ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 67~71
The history of the paper industry has shown a strong technological evolution which has been an essential factor in achieving low cost, high quality paper products and in sustaining the strength of the industry. In the last decades paper machine development has been rapid. This has helped to establish paper as a "low cost" material. In future, the pressure from the competing media will only accelerate the technological efforts to improve cost and functional'||'&'||'not;ity of paper. In addition, in the future, technological advances will be combined with innovation in busi'||'&'||'not;ness concepts. Certain production methods are likely to be developed which will distribute current process stages outside the paper mill. Papermakers can begin to reduce their invest'||'&'||'not;ment risk by subcontracting large-scale base paper production but taking responsibility for the higher value finishing process stages. Finishing will be more closely integrated with the final use. The role of technology supplier to the paper industry will naturally evolve to reflect all these changes. Metso is already actively collaborating downstream in the different paper-related business chains. This collaboration will be crucial for implementation of new business and technology innovations in P'||'&'||'P industry and Metso will certainly benefit from its catalyst role in this transition.
Modern Paper Quality Control
Komppa, Olavi ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 72~79
On the other hand, the fiber orientation at the surface and middle layer of the sheet controls the bending stiffness of paperboard. Therefore, a reliable measurement of paper surface fiber orientation gives us a magnificent tool to investigate and predict paper curling and cockling tendency, and provides the necessary information to fine-tune the manufacturing process for optimum quality. Many papers, especially heavily calendered and coated grades, do resist liquid and gas penetration very much, being beyond the measurement range of the traditional instruments or resulting inconveniently long measuring time per sample. The increased surface hardness and use of filler minerals and mechanical pulp make a reliable, non-leaking sample contact to the measurement head a challenge of its own. Paper surface coating causes, as expected, a layer which has completely different permeability characteristics compared to the other layers of the sheet. The latest developments in sensor technologies have made it possible to reliably measure gas flow n well controlled conditions, allowing us to investigate the gas penetration of open structures, such as cigarette paper, tissue or sack paper, and in the low permeability range analyze even fully greaseproof papers, silicon papers, heavily coated papers and boards or even detect defects in barrier coatings! Even nitrogen or helium may be used as the gas, giving us completely new possibilities to rank the products or to find correlation to critical process or converting parameters. All the modern paper machines include many on-line measuring instruments which are used to give the necessary information for automatic process control systems. Hence, the reliability of this information obtained from different sensors is vital for good optimizing and process stability. If any of these on-line sensors do not operate perfectly as planned (having even small measurement error or malfunction), the process control will set the machine to operate away from the optimum, resulting loss of profit or eventual problems in quality or runnability. To assure optimum operation of the paper machines, a novel quality assurance policy for the on-line measurements has been developed, including control procedures utilizing traceable, accredited standards for the best reliability and performance.
Printing and Paper Industry in Digital Era
Moon, Sang-Hyun ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 5, 2000, Pages 80~85
The objective of this article is to review the impact of emerging information technology on printing and paper industry. Todays developing information technology affects every corner of ones daily life and will bring dramatic changes in printing and paper industry, which should be regarded as definite trend that every participant in the industry must follow in any manner. Reviewing relevant technologies and quoting recent survey conducted by Boston Consulting Group will hopefully lead to a basic understanding of the impact of the transition of information distributing methods on printing and paper industry.