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Volume 47, Issue 3
Displaying 1-13 of 13 articles from this issue
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Tatsuo Masuda1993 Volume 47 Issue 3 Pages 323-327
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
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Shiro Kobayashi1993 Volume 47 Issue 3 Pages 328-333
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
JOURNAL FREE ACCESSThe first successful chemical synthesis of cellulose is mainly reviewed in connection with related synthetic organic reactions in the carbohydrate chemistry field. The synthesis is a completely novel polymerization, which uses cellulose as catalyst for the polymerization of β-D-cellobiosyl fluoride substrate monomer. The product of the water-insoluble part had DP22 and a similar structure with natural cellulose, characterized by CP/MAS 13C NMR, IR spectra as well as X-ray analysis. This enzymatic polymerization technique is expected to contribute to glycotechnology to prepare new oligo- and poly-saccharides.View full abstractDownload PDF (2558K) -
Yasuhiko Sasagawa, Osamu Ishikazva, Takanori Yamashita, Akira Tsuji1993 Volume 47 Issue 3 Pages 334-339
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
JOURNAL FREE ACCESSTwo types of the newly improved SB-latex can provide good performance for coated paper. The first one is the latex which provides better balance between blistering resistance and picking strength for web off-set printing coated paper. It is difficult to reconcile blistering resistance with picking strength only by controlling gel content of latex. Reducing gel contents can give good blistering resistance with the porous coated layer. But the porous structure causes poor picking strength, and vice versa. The newly devised latex has greater thermal sensitivity to the melt flow of latex polymer by changing the quality of gel into higher homogeneous molecular distribution and carboxyl group distribution. This sensitivity results in not only a small pore coating structure which gives good picking strength but also large deformation of pores under high temperature in order to attain good blistering resistance. Dynamic viscoelasticity both of latex film and coating layer was measured. Usefulness of the dynamic viscoelastic measurements in characterizing latex polymer and coating layer is demonstrated. Another one is a newly developed cationic modified latex. Controlling surface electric state of latex can provide suitable interaction between latex and pigment in coating. Such interaction gives coating structure adequate porosity for less print mottle of coated paper. Generally, Tg is the key factor to improve print mottle. Lower Tg latex provides less print mottle due to the produced bulky and porous coating structure. However, lower Tg latex tends to provide poor wet picking strength and poor stiffness. The moderate cationic latex performed less print mottle without reducing Tg. The effect of the moderate cationic latex on print mottle was verified by pilot coating and commercial press.View full abstractDownload PDF (664K) -
A. J. Cleland, R. A. Slepetys1993 Volume 47 Issue 3 Pages 340-346
Published: March 01, 1993
Released on J-STAGE: April 23, 2010
JOURNAL FREE ACCESSA novel technique has been used to quantitatively characterize the shape of kaolin clay pigments. The technique is based on the divergence of particle size measurements made using two different methods, namely sedimentation and light scattering.
Two sets of kaolin pigments, one delaminated and one non-delaminated, were prepared and characterized using this technique. The shape factors were higher for the delaminated series, indicating that these pigments contained platier particles. Finally, the pigments were evaluated in both LWC rotogravure and offset coating formulations in order to derive quantitative relationships between performance properties, shape factor, and particle size.View full abstractDownload PDF (1009K) -
T. Kröhl, D. Horn, P. Lorencak1993 Volume 47 Issue 3 Pages 347-354
Published: March 01, 1993
Released on J-STAGE: April 23, 2010
JOURNAL FREE ACCESSThe counting of colloidal pitch by means of a haemocytometer is nowadays an accepted analytical method, but it is time consuming, it gives no information on size distribution of pitch particles, and the results depend on the person counting. A new analytical method has been developed at our laboratories in which the pitch is dyed with a fluorescent dye. The colloidal pitch is then separated from the fibres and passed through a capillary, and the individual particles are hydrodynamically focused. A laser beam passes through the stream of single particles and excites the dye. The intensity of the fluorescent light is proportional to the volume of each pitch particle, and the particle count per unit of time is a measure of the pitch concentration. A personal computer is used to count the particles and to analyse their size distribution.
This method is an excellent tool for evaluating the efficiency of pitch control aids. When a single cationic polymer was added, it was found that the decrease of the pitch count was a function both of the level of addition and the charge density (and other properties) of the polymer. When a combination of poly-electrolytes was added, both an increase and a decrease in the pitch count was observed, which depended on the polymer concentration, the concentration ratio, the order in which they were added, and the time elapsed between adding them. The polymers evaluated included polyethylenimines, poly-DADMAC, and dicyan-diamide resins. This method can easily be combined with measuring the zeta potential of pitch particles, which leads to a better understanding the mechanisms involved.View full abstractDownload PDF (4645K) -
Yoshiyuki Omori1993 Volume 47 Issue 3 Pages 355-362
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
JOURNAL FREE ACCESSRecently paper machine has been operated at high speed, ex. 1, 000 m/min and more. Paper machine guide device regulates running position of dryer fabrics.
Palm of guide device detects a position of dryer fabrics in contact with running dryer fabrics. Dryer fabrics touch palms strictly, and scrub it, and cause abrasion of dryer fabrics. Palm is sometimes cut off because of this abrasion. Palm break will cause unstable running of the dryer fabrics and make the damage.
Paper machine constructors took the remedy for this kind of trouble, they coated ceramic on the palm surface in order to prevent the abrasion of it.
However there were many edge troubles reported on the dryer fabrics, which were caused by the hardness of ceramic itself and the frictional heat resulting from hard contact with the dryer fabrics.
We carefully studied this reason and completed the remedy as follows.
We improved the resin which harden and protect the edge of dryer fabrics from abrasion.
Weaving of an excellent thread with abrasion resistance prevented dryer fabrics.
We developed new coating material for the palm surface, which prevent from abrasion.
This is reporting the process of our study and the results of our experiment.View full abstractDownload PDF (5388K) -
H. Takahasi, S. Seo, K. Mizuno, M. Sakiyama1993 Volume 47 Issue 3 Pages 363-370
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
JOURNAL FREE ACCESSOn 22 pieces of broken centrifugal cast rolls the cause of breakage is studied. Then it has been concluded that a fatigue crack is initiated at casting defects or inclusions, corrosion occurs at casting defects and this part acts as an origin of fatigue cracking. Forged suction roll has no such defects although one breakage and two cracking troubles were experienced. The origin of fatigue cracking is studied in case of the forged suction rolls by the fractography and stress analysis of the FEM. A crack on the axial direction is created by a shortage of wall thickness which was designed wrong. A crack on the circumferential direction is created by a combination of stress concentration at the irregularly narrow drilled portion and maximum stress shifting based on wrong maintenance.View full abstractDownload PDF (5506K) -
Seikichi Kobayashi, Osamu Katayose1993 Volume 47 Issue 3 Pages 371-380
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
JOURNAL FREE ACCESSThe new twin-roll press with the displacement concept was introduced to market in 1975 by Sunds Defibrator, Sweden. Since then more than 160 machines has been delivered to various applications such as brown stock, post oxygen washing and bleaching of chemical pulps.
The dewatering press is used for interstage washing, high consistency refining and hydrogen dioxide bleaching of CTMP as well as in the prior stage of flash drying of all grades of pulps. More than 200 dewatering presses have been sold worldwide since the beginning of 1960. The dewatering presses are also used in the viscose industry and Sunds Defibrator has delivered about 180 units to that area.
The worldwide demand for industrial activities to answer the recent highly restricted environmental pollution abatement continually increases. Pulp and paper industry is of course no exception and is required to put more emphasis on design of processes and machinery associated to cut down pollutant substances. The well proven rigid constructed displacement press is a key machine with good combination of dewatering and displacement principle can minimize carry-over of not only solved inorganic material but also dissolved organic material to the subsequent bleaching process in beneficial for economic and environmental reasons. The incoming trend demanding wholly chroline free product needs more selection condition in the newly developed bleaching sequence with chemical of ozon and/or hydrogen peroxide and Sunds Defibrator's twin-roll displacement press overall performs other types of washers such as filters and diffusers.
Mill data and simulations show a new main criterion by which real washing efficiency is judged-low wash loss of dissolved organic material is of great importance to minimize bleaching chemical consumption and decrease discharge of pollutant. Building volume is another point to be considered-the twin roll press offers comparatibly low civil engineering cost.View full abstractDownload PDF (13373K) -
1993 Volume 47 Issue 3 Pages 381-390
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
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[in Japanese]1993 Volume 47 Issue 3 Pages 391
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
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The behavior of wood resin during kraft pulping and pitch problems Part 3Zensaku Abe1993 Volume 47 Issue 3 Pages 392-397
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
JOURNAL FREE ACCESSIn order to obtain the better understanding of pitch trouble during kraft pulping, effects of bark were investigated using Bunanoki (Fagus crenata BLUME), Arakasi (Cyclobanopsis glauca OERST.), and Sudajii (Castanopsis cuspidata var. SIEBOLDII NAKAI) as raw materials. The results are as follows :
1. The amount of unsaponifiable materials in bark is about several to tens times of that in wood.
2. The amount of unsaponifiable materials in raw chips increases remarkablely with increasing contamination of bark in the chips.
3. The occurrence of pitch trouble during kraft pulping are enhanced remarkablely with increasing contamination of bark in the chips.
4. A lot of red color specks as pitch trouble were counted on the bleached kraft pulp produced from the Sudajii raw chips containing bark of 10% ; in those chips the content of unsaponifiable materials was 0.26 wt%.
5. It was confirmed again that the amount of unsaponifiable materials in the raw chips can be used as an indicator of pitch trouble during kraft pulping.View full abstractDownload PDF (716K) -
(Part 1) Flow characteristics in flow passage modelAkira Eguchi, Yasuhiro Sueoka, Mutsuo Kuragasaki, Tetsuo Makino1993 Volume 47 Issue 3 Pages 398-406
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
JOURNAL FREE ACCESSInvestigation was made on flow characteristics in a headbox using the flow model and the headbox scale model. This study was conducted, first to find factors which cause off-axis flow at the side of headbox, and to control these factors.
The results are as follows
(1) Boundary layer develops at the side wall of the headbox. Consequently outward flow is induced at the side of jet due to rectifying effect of the slice lip.
(2) Flow direction in jet is controllable from outward to inward using bleed and increasing flow at the side wall.
Our results clarified causes of the off-axis flow which is one of the factors that cause paper-deformation often seen at the edge of paperweb, and these results gave us clues to solve this deformation problem.View full abstractDownload PDF (5304K) -
1993 Volume 47 Issue 3 Pages 407-415
Published: March 01, 1993
Released on J-STAGE: November 19, 2009
JOURNAL FREE ACCESSDownload PDF (1512K)
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