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Volume 21, Issue 8
Displaying 1-9 of 9 articles from this issue
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[in Japanese]1967 Volume 21 Issue 8 Pages 419-425
Published: August 01, 1967
Released on J-STAGE: November 11, 2009
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Saisei Miyao, Yukio Okamoto, Junzo Nakano, Nobuhiko Migita1967 Volume 21 Issue 8 Pages 426-431
Published: August 01, 1967
Released on J-STAGE: November 11, 2009
JOURNAL FREE ACCESSIt is a well known fact that the addition of polysulfide or borohydride into kraft cooking liquor results in higher yields than an ordinary kraft cooking. This can be explained by a stabilization of carbohydrates during both cookings. The behavior of delignification does not seem to have been investigated kinetically. This work aimed to provide some information about the kinetics of delignification rate during high yield alkaline cooking.
Wood meal used in this study was Akamatsu (Pinus densiflora SIEB. et ZUCC.) extracted with alcohol-benzene (1 : 2). All of the digestions were carried out by the two stage process; the first stage was pretreated with polysulfide (Na2S4) or borohydride (NaBH4), and then pretreated wood meals were cooked with an ordinary kraft or soda cooking liquor at the second stage. The results are summarized as follows :
1) Both polysulfide-alkaline and borohydride-alkaline cookings give about 6 and 8 per cent higher pulp yield at the same content of lignin than does an ordinary alkaline cooking.
2) In each of the alkaline cooking two sets of delignification reactions are involved, whereby the first one is rapid and intensive and the second and subsequent one is slower and weaker in its behavior.
3) There is no difference of the delignification rate during the over all reaction between polysulfide-kraft and an ordinary kraft cookings.
4) Delignification rate during borohydride-kraft cooking is evidently slower than does ordinary kraft cooking.
5) The increases in pulp yield by the pretreatment with polysulfide or borohydride is mainly originated from the stabilization of carbohydrates against alkaline peeling. This stabilization effect appeares in the early stage of the alkaline cooking.View full abstractDownload PDF (900K) -
Reaction of Polyamine with EpichlorohydrinSeishi Machida, Mikio Araki, Yuji Yanagida, Takashi Matsubara1967 Volume 21 Issue 8 Pages 432-438
Published: August 01, 1967
Released on J-STAGE: November 11, 2009
JOURNAL FREE ACCESSIn relation to the wet strength treatment of paper, alkaline-curing resins composed of polyamine and epichlorohydrin were investigated.
Epichlorohydrin was reacted with ethylenediamine, diethylentriamine and polyethyleneimine respectively in methanolic or aqueous solution. The mechanism of reaction was pursued by determining total amino, tertiary amino and epoxy groups in the reaction system, and the condensation products were analysed.
At the reaction temperature of 2030 °C, the amount of tertiary amino group was found to increase according to decrement of that of epoxy group, while the amount of total amino group scarcely changed through the reaction time. The fact impiles that a simple addition reaction such as aminochlorohydrin formation is principally occured as the initial reaction of the condensation. This reaction is facilitated by excess of epichlorohydrin and at higher temperatures. At the higher temperature than 50 °C, however, the amount of total amino group was reather found to decrease; especially in the case of polyethyleneimine the decrement was recognized even at lower temperatures than 2030 °C. The fact would be due to the quarternarization of amino group of aminochlorohydrin mainly by intermolecular cross-linking as side reaction. Excess of epichlorohydrin and higher reaction temperature facilitated the cross-linking to give precipitation. But in many cases, the precipitation is still soluble in hot water if added.
The precipitation was separated by filtration, and the condensation product at the early stage which is water-soluble was obtained by evaporating the reaction mixture under reduced pressure. Both the product and the precipitation were analysed by IR spectra, and each substance was still found to contain many reactive groups indicating the possibility to give more complex polymer by curing. A water-insoluble polymer as the final condensation product was obtained by the curing. A structure of the cured resin was presumed from these experimental results.
It was inferred that the polyethleneimine, when applied as the neutral-and alkaline-curing wet-strength resin to the paper, is desirable to have a long linear structure with lesser branching, if possible.View full abstractDownload PDF (1031K) -
5. Electron Microscopic Studies of Surface Fine Structure of Coated Papers (I)Rikizo Imamura, Akiyoshi Yamaoka, Koji Aoki1967 Volume 21 Issue 8 Pages 439-444
Published: August 01, 1967
Released on J-STAGE: November 11, 2009
JOURNAL FREE ACCESSA series of electron microscopic studies was carried out to make clear the surface fine structure of clay coated papers. The present work forms part of those studies and deals mainly with coating clays. The clays used are kaolin, sericite, roseki-clay and hydrated halloysite and were coated on a stock paper by using casein as a binder.
The results obtained are as follows :
(1) The one stage replica method, which was carried out by evaporating carbon an leaf, was found to be the most suitable technique for the purpose of this case.
(2) The surface of clay handcoated papers was observed to consist of the clay layers parallel to paper surfaces. And it was found that their fine structure depends largely upon the shape and size of clay particles.
(3) By comparing the surface of non-supercalendered coated papers with those of supercalendered coated papers, the effect of supercalendering was found to vary corresponding to the clays used.View full abstractDownload PDF (11302K) -
Rikizo Imamura, Akiyoshi Yamaoka, Shozo Maeda1967 Volume 21 Issue 8 Pages 444-450
Published: August 01, 1967
Released on J-STAGE: November 11, 2009
JOURNAL FREE ACCESSThis electron microscopic study was made with regard to the kaolin handcoated papers with various binders. The binders used are casein, modified starch and Dow Latex 512R. The contents of experiments are as follows :
(1) In addition to one stage replica method described in our last paper, the two stage replica method modified was used. The later method was found to be useful especially for the case of using synthetic latex as binders.
(2) By applying the above two methods, the surface fine structure of all specimens was successfully studied. Further, the effect of supercalendering was studied and it was found that effect were different with the binders used.
(3) The clay handcoated papers with various binder levels were prepared keeping a solid content. Their surface was found to be covered with binder films in proportion to the binder levels. And also the etched surface of them by ion impact was observed.
(4) In addition, the clay coated films were prepared on a glass sheet and their two sides were observed. The surface of the glass side was discussed in connection with cast coating technique.View full abstractDownload PDF (13589K) -
[in Japanese]1967 Volume 21 Issue 8 Pages 451-454
Published: August 01, 1967
Released on J-STAGE: November 11, 2009
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[in Japanese]1967 Volume 21 Issue 8 Pages 455-458
Published: August 01, 1967
Released on J-STAGE: November 11, 2009
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[in Japanese]1967 Volume 21 Issue 8 Pages 459-466
Published: August 01, 1967
Released on J-STAGE: January 25, 2010
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[in Japanese], [in Japanese]1967 Volume 21 Issue 8 Pages 467-470
Published: August 01, 1967
Released on J-STAGE: November 11, 2009
JOURNAL FREE ACCESSDownload PDF (769K)
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