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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
Strength Property Improvement of OCC-based Paper by Chemical and Mechanical Treatments (II)
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 1~7
In the previous experiment, it was found that OCC pre-treatment with Hobart mixer at 20-25％ consistency for 3 hrs or more followed by the application of the equal refining time, caused the increase of tensile strength, burst strength, compressive strength and tear resistance, compared to the no pre-treated. Four completely different fibers, which were Hw-BKP, Sw-BKP, White ledger, and OCC were selected for this experiment to investigate the effect of mechanical pre-treatment process on different fibers. From the experiment, it was found that the mechanical pre-treatment did not decrease fiber length at all, but decreased freeness, com-pared to the no pre-treated, when the same refining time was applied. WRVs of the pre-treated fibers were higher than the no pre-treated at the same freeness level. It was speculated that the mechanical pre-treatment induced only hydrophilic nature of fibers without damaging fiber length by delaminating fiber walls. The fiber surface area and the physical strength differences of handsheets will be discussed in the next publication.
Strength Property Improvement of OCC-based Paper by Chemical and Mechanical Treatments (III) - Handsheet physical properties -
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 8~15
This study is a continuation of the previous experimental analysis and is mostly focused on handsheet strength properties. Four completely different fibers, which were Hw-BKP, SW-BKP, White ledger, and OCC, were selected to investigate the effect of mechanical pre-treatment by Hobart mixer on handsheet strehgth properties. After equal time mechanical pre-treatment, the fibers were refined with laboratory valley beater for 10, 20 and 30 minutes, and handsheets were prepared from the fibers for physical strength comparison. Handsheets from SW-BKP and OCC showed 5-30% increase of breaking length, burst index, tear index, and compression index while handsheets from HW-BKP and White ledger no increase except tear index. In Hobart mixer pre-treatment, HW-BKP and White ledger fibers were easily attached to the wall of the mixer bowl and mechanical action was not effectively applied. The fiber length of Hw-BKP and White ledger were 0.837 mm and 1.591 mm, respectively, while SW-BKP and OCC were 2.744 mm and 2.033 mm, respectively, in weight weighted length. The effective mechanical pre-treatment seems to be related to the fiber length. Tear indexes of the pre-treated furnish were much higher than no pre-treatment at the same breaking length level.
Evaluation of Soft Nip Calendering Characteristics of Newsprints
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 16~25
The influence of four process parameters of soft nip calendering including calendering pressure, temperature, moisture content and nip residence time on bulk, smoothness and tensile strength of newsprints has been investigated. In addition, the effect of basis weights on calendering responses has been examined. Bulk of newsprints decreased and smoothness increased with the increase of the calendering pressure, temperature, moisture content of the sheets and nip residence time. Improvement in tensile strength was observed when low calendering pressure and high temperature of heat-ing roll were employed. Tensile strength of the newsprint, however, decreased abruptly when the calendering temperature and pressure increased above certain levels due to the rupture of sheet structure, which has been verified by SEM. SEM micrographs also showed that it would be possible to maintain the inner bulk while densifying the fibers on the outer surface of newsprint by adjusting the soft nip calendering variables properly.
Evaluation of the Nip Pressure Profile and Analysis of Heat Transfer in Soft Nip Calender
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 26~34
Understanding the nip geometry and heat transfer phenomena of soft nip calenders, which has been used in the production of newsprint and coated papers for many years, is very important since improper setting of soft nip calendering conditions causes deterioration of paper quality and productivity. In this study theoretical analysis on nip pressure and heat transfer phenomena in the nip of soft nip calenders has been made. The variables examined were calendering pressure, surface temperature of the heating roll, nip residence time and ingoing sheet moisture, By measuring nip widths and maximum nip pressure with Prescale film at a normal temperature, accurate line load has been obtained. With this line load, nip pressures at different temperature and nip widths were calculated. Results showed that as temperature increased, nip widths increased and nip pressures decreased. Equations derived for the heat conduction phenomena in soft nip calender nip were derived based on the semi-infinite plate and finite difference method and were used for the analysis of heat transfer within the nip. Temperature profiles in z-direction of paper within the nip were obtained. Finite difference method allowed more accurate analysis of the heat transfer in the calender nip. In this study newsprint and coated paper were considered as a single plate and two-layer plate consisted of sheet and coating layers, respectively. Heat trans-fer to paper increased as heated roll surface temperature and nip residence time were increased.
Quantitative Analysis of Pulp fiber Characteristics that Affect Paper Properties (II)
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 35~39
Refining is very important process of fibers treatment for proper paper properties. An extent of refining is usually measured by freeness, although freeness gives complicated meanings. One of a direct way of studying the refining effects on pulp fibers is making photomicrographs of beaten fibers. The conventional microscopy like light microscopy(LM) and scanning electron microscopy(SEM) require to preserve the wet structure of pulp fibers morphologically since most of papermaking process is carried out almost entirely in water. Recently developed microscopy, especially confocal laser scanning microscopy(CLSM), offers the possibility of examining fully hydrated pulp fibers. Cross-sectional images of wet pulp fibers are also generated using optical sectioning by CLSM and image analysis in order to verify and quantify the extent of fiber wall swelling indicating the internal fibrillation. At low beating load such as 2.5 kgf, in the same freeness, breaking length is higher than that of high beating load such as 5.6 kgf. fiber wall thickness at low beating load is greater than that at high beating load. This result is accounted for the fact that internal fibrillation in the low beating load was high.
Microscopic Observation of White Ledger Ozone Deinking
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 40~44
A microscopic study was carried out to get the fundamental informations for the ozone deinking technology. The differential interference microscopic observation showed that ozone treatment was helpful to detach the toner ink from the surface of pulp fiber. The modifications of fiber surfaces by ozone treatment were observed with scanning electron microscope. Modification of fiber surfaces was not severe at the early stage of ozone treatment, but it increased with ozone treatment time and pulp consistency, Therefore, it would be possible to improve the properties of deinked pulp by controlling the condtion of ozone treatment.
Development of Decolorizing Method for Color Ledger
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 45~50
This study was to get the optimum conditions on bleaching by mixing of various colored ledgers with white ledger by 50：50 ratio. This bleaching was carried out by two steps, reductive-oxidative process was shown a better brightness compared to oxidative-reductive one. Especially, in reductive bleaching using sodium hydrosulfite, the aging temperature should keep above 6
irrespective of aging time, alkaline condition was more effective than acid one. Final brightness after bleaching and feinting was obtained over 78% to be used by the raw pulp of tissue.
Effect of Vat Control in Cylinder Machine on Physical Properties of Paper
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 51~57
Cylinder machine usually gives more fiber orientation than fourdrinier and has limitation in machine speed because of fiber wash-off caused by centrifugal force when machine speed increases. This study aimed for the improvement of paper formation and productivity by setting an apron in vat inlet and by adjusting mould water head. Improvement of formation and increase of machine speed were achieved, which ultimately improve productivity. Installing an apron successfully decreased fiber wash-off. Fiber orientation and two-sideness of ash distribution became less severe. The proper adjustment of water head inside the cylinder mould proved to be an important factor not only in paper formation but also in decreasing paper two-sideness.
Development of Pulping Methods of Rice-straw Chemical Pulp with Higher Yield and Lower Kappa Number
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 58~67
This study was carried out to acquire basic data necessary for the use of non-wood pulp. Various chemical pulping methods for rice straw to achieve higher yield, lower Kappa No. were investigated and then the physical properties of various pulps were tested. The results of this study were as follows: When various chemical pulps (Soda, Soda-AQ, Soda-
, AS, AS-AQ, AS-
, Kraft) were produced with rice-straw, the pulps with the highest yield and lowest Kappa No. were obtained with Soda-
pulps. For the breaking length, Soda and Soda-additive pulps(7.5~9.2km) were better than AS and AS-additive pulps(6.2~8.1km). Similarly, for the burst index, Soda and Soda-additive pulps(6.0~7.0 kPa.
/g) were better than AS and AS-additive pulps(4.5~6.3 kPa.m
/g). But the tear index was showed 21.8-30.9 mN.
/g with a little different between pulping methods.
The Characteristics of the Japanese Paper Industry and Its Concerns for Globalization
Kiyoaki Iida ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 59~59
The Characteristics of the Japanese Paper Industry and Its Concerns for Globalization
Iida, Kiyoaki ;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 32, issue 2, 2000, Pages 68~73