JAPAN TAPPI JOURNAL

Present Status and Future Prospects of Artificial Fiber Papers

Yoshinari Kobayashi, Rokuro Maematsu

1978 Volume 32 Issue 8 Pages 443-450
Published: August 01, 1978
Released on J-STAGE: January 22, 2010

DOIhttps://doi.org/10.2524/jtappij.32.8_443

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Pulp and Paper Mills in Japan (1)

-Kasugai Mill, Oji Paper Co., Ltd.-

Oji Paper Co. Ltd.

1978 Volume 32 Issue 8 Pages 451-462_1
Published: August 01, 1978
Released on J-STAGE: November 10, 2009

DOIhttps://doi.org/10.2524/jtappij.32.8_451

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(III) Improvement and Progress of Wet Part of Paper Machine

Sueki Ueda

1978 Volume 32 Issue 8 Pages 463-469
Published: August 01, 1978
Released on J-STAGE: November 10, 2009

DOIhttps://doi.org/10.2524/jtappij.32.8_463

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[title in Japanese]

1978 Volume 32 Issue 8 Pages 470
Published: August 01, 1978
Released on J-STAGE: November 10, 2009

DOIhttps://doi.org/10.2524/jtappij.32.8_470

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Mechanical Properties of Paper under Impact Conditions (3)

Effect of Impact Velocity

Minoru Kimura, Takashi Kadoya

1978 Volume 32 Issue 8 Pages 471-475
Published: August 01, 1978
Released on J-STAGE: November 10, 2009

DOIhttps://doi.org/10.2524/jtappij.32.8_471

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Paper is usually subjected to stress or strain under dynamic conditions concerning its uses. Therefore, it is important to obtain the information of mechanical properties of paper under impact conditions. This paper deals with the impact behavior of paper at different rates of impact elongation.
The summary in this study is as follows.
(1) Time-to-failure of NBKP sheets decreases with increasing rates of impact elongation. Strain-to-failure, however, remains a constant value within the impact velocity range in this study. These results are in agreement with those of static load-elongation tests.
(2) Impulse decreases with increasing rates of impact elongation. The behavior of impulse with impact velocities is similar to that of time-to-failure. On the contrary, energy absorption increases with increasing rates of elongation. This seems to show that the critical velocity by von Kármán exists at higher impact velocity level than that adopted in this study.

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On the Z-direction Compressive Elasticity of Paper

Shigeyoshi Osaki, Yoshihiko Fujii

1978 Volume 32 Issue 8 Pages 476-484
Published: August 01, 1978
Released on J-STAGE: November 10, 2009

DOIhttps://doi.org/10.2524/jtappij.32.8_476

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The compressive modulus. B' and the compressive viscosity η of a handmade paper were measured for the Z-direction (the direction perpendicular to the surface). The modulus was obtaind by the dynamic and the static methods while the viscosity was obtained by the dynamic method. The value of B' increased from 10⁷ to 10¹⁰ (dyn/cm²) by application of pressure while the value of η from 10⁴ to 10⁷ (poise). It was also found that these values increased with the apparent density of the paper. The water absorbed in the paper also affected on these values.
The structure of the cross section parallel to the Z-direction in the paper was observed by means of the scanning electron microscope in order to clarify the correlation between the structure and the modulus. It was found that B' incrased with the decrease of void fraction which was measured with the electron micrograph.

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Studies on SO₂ and MgSO₄ Cooking

Chemical Cooking of Larch and Red-pine, and Recovery of MgSO₄ from Cooking Waste Liquor

Tutomu Suzuki, Kunio Tosaka, Jisuke Hayashi

1978 Volume 32 Issue 8 Pages 485-494
Published: August 01, 1978
Released on J-STAGE: January 22, 2010

DOIhttps://doi.org/10.2524/jtappij.32.8_485

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Larch and red-pine chips, which were composed of sap-and heart wood by equal weight, were cooked in the liquor of 32% SO₂ and 24% MgSO₄ the same cocentration as in the chemical pulping of spruce and it has been examined whether the quality of the pulps is good or not.
The relationship between cooking temperature and time to obtain chemicalpulp from larch or red-pine were 6, 4, and 3 hrs. at the temperatures of 135° to 140°, 150°, and 160°C, respectively.
All these pulps contained the considerable amount of screenings of 10 to 20% by weight based on an ovendry wood, but they were easily defiberated with Disc-refiner.
Screened yield and paper strength of the pulps obtained from larch or red-pine at 135° to 140°C were comparable or superior to those of Mg-base sulfite pulps.
When cookings of these species were carried out with the same temperature-time schedule as in the sulfite, so-called easy-bleaching type, screening yields of pulps became higher and also reject stocks were significantly reduced.
The pulps showed excellent paper strength comparable to KP, and furthermore the yield of fiber stock was superior to that of KP.
The recovery of MgSO₄ as a cooking chemical from waste liquors of softwoods was investigated.
The recovery was not dependent on the type of waste liquor but on the degree of carbonization of waste liquors by evaporation.
The chemicals was completely separated from highly carbonized substance by washing with water.
However, in low degree of carbonization, the two-steps washing with SO₂ solution and water was required for the full separation of the chemical.

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[title in Japanese]

1978 Volume 32 Issue 8 Pages Preface10-Preface13
Published: August 01, 1978
Released on J-STAGE: November 10, 2009

DOIhttps://doi.org/10.2524/jtappij.32.8_Preface10

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