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紙パ技協誌46(6), 790-798(1992).
作動トランスを用いた膨潤による紙の厚さ変化の短時間連続測定
東京大学農学部
江前敏晴、稲田宏之、尾鍋史彦、臼田誠人
ABSTRACT
水の浸透時に起こる紙の膨潤度を測定する方法として厚さの変化を測定した。プラスックチューブで３方向から水を供給する方法を用い、作動トランスを使用して測定を行い、短時間での連続測定に成功した。また紙の重量増加を測定することとの対応により、サイズ紙では吸収量の増加より遅れて膨潤が始まることが明らかになった。またこの方法はブリストー試験の吸収曲線とは対応しないことも明らかになった。
Japan Tappi
J.(Kamipa Gikyo-shi)46(6), 790-798(1992).
Faculty of
Agriculture, University of Tokyo
Toshiharu Enomae, Hiroyuki Inada, Fumihiko Onabe and Makoto Usuda
As for
mechanism of liquid penetration, Lucas-Washburn's equation has been applied for
years. Oil penetration is sure to be suited to this equation. But, water tends
to deviate from it, which was confirmed also by the authors with weakly-sized
paper. One of the main reasons for this is swelling. Swelling means the phenomenon
of increasing volume when the material absorbs liquid. In case of paper it
actually appears as increase in thickness including structural change resulting
from interfiber debonding.
In the present
study, we aim at measuring rapid thickness increase of paper precisely. For
this purpose an new system for measuring thickness change was experimentally
created using a differential transducer. How swelling is involved in liquid
absorption mechanisms was discussed in comparison with the data obtained by traditional
Cobb's method and the results showed that
1. Rapid
increase in paper thickness just after contact with water was able to be
measured continuously with newly-developed differential transducer system.
2. Capillary
absorption following by swelling occurs for sized paper from the result of
comparison between water absorption volume and thickness increase measured with
a using a differential transducer system.
3. Thickness
increase measured with a differential transducer system did not correspond to Bristow's
curve because of difference in penetration way. Therefore, simultaneous
measurement system of thickness and absorption volume is required.