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Volume 37, Issue 10
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Hot CalenderingKyuzaburo Ishiguro1983 Volume 37 Issue 10 Pages 865-882
Published: 1983
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSCalendering plays a very important role in determining the final paper properties. In order to minimize the mechanical stress applied on paper and to acquire the desired paper properties, number of nips and nip pressure have been reduced recently.
These techniques aim at reducing mechanical damages of paper, and obtaining smooth surfaces, as well as maintaining adequate physical properties of paper such as strength and dimensional stability.
The hot calendering roll and the crown control roll have been developed to meet these requirements.
This paper summarizes the past studies of calendering effects on paper properties, and introduces the research at PPRIC on hot calendering, and furthermore describes different kinds of hot calendering rolls and temperature-gradient calendering.
Proper controls of basis weight and moisture profile in cross machine direction at the inlet of a calender are the prerequisites even in hot calendering and temperature gradient calendering.
Lack of these conditions will lead to anisotropic expansion of paper.
A method for calculating the magnitude of anisotropic expansion and its effect on nip pressure is presented.
Appropriate choise of calendering method can minimize paper strength loss and can decrease the use of costly papermaking furnishes, which will bring us economic returns.View full abstractDownload PDF (6163K) -
Akira Yamaguchi1983 Volume 37 Issue 10 Pages 883-891
Published: 1983
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe state of the art in pulping technology will be reviewed in five or six serial reports. This paper deals with forcussing on the following articles.
1) General tendency in pulping technology.
2) Trend of pulping method and production.
3) The state of the art in chipping, screening and handling.View full abstractDownload PDF (5522K) -
1983 Volume 37 Issue 10 Pages 892
Published: 1983
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (67K) -
ISWPC Executive Committee1983 Volume 37 Issue 10 Pages 893-913
Published: 1983
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (10706K) -
-Shirakawa Mill, Mitsubishi Paper Co., Ltd.-Mitsubishi Paper Mills Ltd.1983 Volume 37 Issue 10 Pages 914-920
Published: 1983
Released on J-STAGE: January 29, 2010
JOURNAL FREE ACCESSMitsubishi Paper Mills, Ltd. was established in 1898 and now has six mills in operation throughout Japan. The company manufactures woodfree printing and writing papers, coated papers and paperboards, specialty papers, market pulps and photosensitive materials.
Shirakawa Mill started production in 1951. The mill is situated in the Fukushima Prefecture to exploit rich water, wood resources and labor force etc. and has a capacity of 100, 000 MT/Y of bleached and unbleached kraft pulp from 100% domestic wood chips and 4, 000 MT/Y of transformer board.
The odorous effuluent is treated by on AS deodorization process.View full abstractDownload PDF (11577K) -
On Brightness of Sugi BKP and Chlorination of FerruginolYoshito Ohtani, Masashi Sumimoto1983 Volume 37 Issue 10 Pages 921-931
Published: 1983
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSAmong eleven components of extractives from the heartwoods of sugi (Cryptomeria japonica)
shown in Figure 3, dehydroferruginol and xanthoperol in addition to ferruginol were found to be responsible for lowering the brightness of sugi BKP.
By the chlorine treatment as the first stage of a multi-stage bleaching, ferruginol (a) converts to 11-chloroferruginol (c), dehydroferruginol (e), 11-chloro-7-hydroxyferruginol (i), and 6α, 11- dichloro-7 β-hydroxyferruginol (g). The latter four (c, e, i, g) as the intermediate compounds in the multi-stage bleaching were shown to afford undesirable effect on the final properties of sugi BKP. Amog the four compounds, the former two (c, e) are the major products at ten minutes after chlorination started, and then the latter two (i, g) follow. One of the reactions occurred at the early stage of chlorination of ferruginol (a), therefore, is formation of the compound (e) via the quinonemethide (q). Conversion to 11-chloroferruginol, on the other hand. is followed by reactions via the corresponding quinonemethide (r). Considering the results mentioned above and those obtained by the direct treatment of dehydroferruginol (e) with chlorine, the whole reaction pathways can be postulated as shown in Figure 11.View full abstractDownload PDF (1178K) -
Shunichi Shinagawa, Kazuyuki Kasuga, Shoichiro Yano, Hyoe Hatakeyama1983 Volume 37 Issue 10 Pages 933-938
Published: 1983
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSCoconut (Cocos nucifera)
coir fiber was pulped by kraft, bisulfite and alkaline sulfite cooking processes for the evaluation of it as a raw material of pulp. In this report, attention was especially paid to the effect of cooking temperature on pulp yields and pulp properties.
The results obtained were as follows.
(1) The coir fiber, which was separated from the coconut husk using a disk-refiner, contained a very small amount of water and alcohol-benzene soluble substances, and contents of lignin and holocellulose were 39.7 and 60.1%, respectively.
(2) The average length and width of the coir fiber were about 0.5 mm and 16μm, respectively.
(3) Pulp yields were dependent on cooking conditions and ranged from 38.1 to 58.7%.
(4) The breaking length and MIT folding endurance increased with increasing cooking temperature. However, the tear factor showed the maximum at a certain temperature in the bisulfite cooking. The maximum breaking lengthes of the obtained pulps were 4.79 km in kraft, 4.54 km in bisulfite and 4.71km in alkaline sulfite cooking processes.View full abstractDownload PDF (704K) -
Hiroo Tanaka1983 Volume 37 Issue 10 Pages 939-948
Published: 1983
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe colloid titration is well known to be a simple and accurate method for analyses of polyelectrolytes. But the problem often encountered in practical usages is remarkable influence of inorganic salts. Then the influece of salts, which are included in paper making white water, was studied on 13 kinds of anionic polymers, 14 kinds of cationic polymers and 6 kinds of amphoteric polymers. The results obtained are as follows.
1) In a direct titration for cationic polymers with PVSK, salts generally increased the amount of PVSK at the end point which sometimes was nearly twice as high as that of true value.
2) In the back titration for anionic polymers with low density of ionic groups, salts decrease the amount of PVSK at the end point. In other words, the concentration was overestimated and sometimes went up to over twice. On the other hand, the concentration of anionic polymers with high density of carboxyl groups was underestimated and sometimes reached below one-half in the presence of salts.
3) Salts also inhibited greatly the metachromasy between TB and PVSK (color change at the end point).
The above phenomena occured even below the average salt concentration in white water in which the ionic strength was about 0.01.
These deficient results were attributable to the higher shielding of ionization in polyions with higher ionic density, acceleration of precipitation of unstoichiometric polyion complex and/or acceleration of the substitution reaction of carboxyl groups by sulfate group in PVSK caused by salts.View full abstractDownload PDF (1565K)
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