JAPAN TAPPI JOURNAL

[title in Japanese]

[in Japanese]

1955 Volume 9 Issue 11 Pages 462
Published: November 15, 1955
Released on J-STAGE: November 17, 2009

DOIhttps://doi.org/10.2524/jtappij.9.462

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[title in Japanese]

[in Japanese]

1955 Volume 9 Issue 11 Pages 463-464
Published: November 15, 1955
Released on J-STAGE: November 17, 2009

DOIhttps://doi.org/10.2524/jtappij.9.463

JOURNAL FREE ACCESS

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[title in Japanese]

[in Japanese]

1955 Volume 9 Issue 11 Pages 465-467
Published: November 15, 1955
Released on J-STAGE: November 17, 2009

DOIhttps://doi.org/10.2524/jtappij.9.465

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[title in Japanese]

[in Japanese]

1955 Volume 9 Issue 11 Pages 468-474
Published: November 15, 1955
Released on J-STAGE: November 17, 2009

DOIhttps://doi.org/10.2524/jtappij.9.468

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[title in Japanese]

[in Japanese], [in Japanese]

1955 Volume 9 Issue 11 Pages 475-480
Published: November 15, 1955
Released on J-STAGE: February 10, 2010

DOIhttps://doi.org/10.2524/jtappij.9.475

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Studies on the Color of Kraft Pulp (II)

On the Change of Color of Alkaline Pulp in Store (under exposing to the Ultra-violet Light)

Takashi Kanda, Tsuneo Matsumoto

1955 Volume 9 Issue 11 Pages 481-486
Published: November 15, 1955
Released on J-STAGE: November 17, 2009

DOIhttps://doi.org/10.2524/jtappij.9.481

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In order to determine whether or not the change of color of pulps in store is connected with the lignin content of pulps, exposing tests to ultra-violet light were carried out on some alkaline pulps whose lignin contents are different in series.The results are shown in the Table 1 and Fig.2
In the case of pulps whose lignin contents are lower than about 15%, the degree of change of brightness of pulps are roughly proportional with their lignin contents.However, the pulps obtained at the early stage of alkali cooking show the tendency that the higher the lignin content, the smaller the change of brightness.
From the results it may be considered that some alteration will take place in lignin molecule before lignin is dissolved in alkali cooking liquor.

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Studies on the Synthetic Resin Coating of Papers

Report I.The Effect of Synthetic Resin Latex Coating on the Air Resistance of Paper

Mitsuo Fujii, Yasuji Otsuka, [in Japanese]

1955 Volume 9 Issue 11 Pages 487-490
Published: November 15, 1955
Released on J-STAGE: February 10, 2010

DOIhttps://doi.org/10.2524/jtappij.9.487

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The authors have studied the effect of synthetic resin latex coating on the air resistance (AR) of paper.Two kinds of commercial latices (latex A and latex B) were used (A is the latex of PVC, T_f=75°C and B the latex of copolymer of VC and vinyliden C, T_f=15°C). T_f is the minimum film-forming temp.of latex and at this temp. one can obtain a film which have no cracks .The authors have reported the important nature of T_f for the practical use of latices (M. Fujii and Y. Otsuka, Chem. of High Polymers, Japan; 119, 93 (1955)).
In this study, the commercial kraft papers were coated with the latices of various conc .and dried under various temp., some of the coated papers were cured at 120°C for 5 min .The AR was measured with Gurler densometer.
The effects of latices on the AR of the papers are highly depend upon the plasticity of the resin particles, in other words, the drying or curing temp.and the important factor to determine those temp .is the T_f of the latices, if the temp. is too high or too low the low AR values are obtained.

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Fundamental Studies on the Process of Wood Cooking

Summary of the First Part

Y. Fukuda, A. Kamba, T. Hatanaka

1955 Volume 9 Issue 11 Pages 491-496
Published: November 15, 1955
Released on J-STAGE: November 17, 2009

DOIhttps://doi.org/10.2524/jtappij.9.491

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1.Comparison of Sulphate with Sulphite process :
We took shavings as thin as approximately 200μ from a kind of spruce (Ezomatsu in Hokkaido Area) and cooked them both by sulphite and sulphate process.The ratio of dissolution of such individual constituents of wood as lignin, pentosan, etc were compared in the whole range of yield while cooking.
Taking the sulphite process first, lignin and pentosan are, at the higher range of yield, removed selectively from the wood-chips without marked degradation of cellulose.The drastic acid hydrolysis of cellulose occurs after the yield of residue reaches nearly 50 per cent.
By the sulphate cooking, on the contrary, the considerable degradation and dissolution of cellulose takes place in the early stage of cooking.The removal of lignin and pentosan, rather than cellulose, are delayed.The topochemical nature of cooking reaction appears more distinctively in the sulphite cooking than sulphate cooking.
The superior mechanical properties of sulfate pulp (to sulphite pulp of the same D.P.) are attributable to the fact that sulphite fibres, which are injured by the acid hydrolysis, have too many cracks or other weak points perpendicular to the axis of fibre, whereas sulphate fiberes degraded mainly by alkaline oxidation, have no weak point even in the case of over-cooking.
Other differences between sulphite and sulphate process are also explained in this report.

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[title in Japanese]

[in Japanese]

1955 Volume 9 Issue 11 Pages 497-501
Published: November 15, 1955
Released on J-STAGE: November 17, 2009

DOIhttps://doi.org/10.2524/jtappij.9.497

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[title in Japanese]

1955 Volume 9 Issue 11 Pages 502-504
Published: November 15, 1955
Released on J-STAGE: November 17, 2009

DOIhttps://doi.org/10.2524/jtappij.9.502

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