In order to clarify the vacuum drying process of insulation paper layer, permeability of water vapor at 110°C, 4 to 0.1mmHg ; and of air at room temperature, atmospheric pressure to 10 mmHg are measured. The results are ;
(1) Air permeation below the order 10 mmHg is of molecular flow and is independent of mean pressure.
(2) The equivalent pore radius of measured paper is about 3 microns.
(3) Water vapor permeation in vacuum drying condition is also considered to be molecular flow and permeability value coincides with that calculated from air permeability.
These informations are useful in analyzing a drying process of paper insulation layer.

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In order to study the adaptability of polyacrylamide for the surface sizing agent, the effects of surface sizing and mechanical properties of polymer films have been investigated, comparing polyacrylamide with the other materials-oxidized starch, CMC, sodium alginate, polyvinylalcohol etc.
Polyacrylamide had the most excellent characteristics and effects in Wax Pick, IGT printability, bursting strength, folding endurance, air permeability, and the film of polyacrylamide was strongest of all.
Polyacrylamide-type surface sizing agent was remarkably affected by pH of base paper and amounts of Alum. added to pulp slurry.

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With the development of thermo-setting synthetic resin adhesives, bonding operations employing hot-platen or roller have been widely practiced in various wood and paper processing, such as plywood, particle board, over-laid panel or resin treated paper production, in order to increase their production rate and improve their bonding quality.
In an adhesive-curing procedure at higher temperature, minimum pressing duration under a specified temperature which assure a sufficient resin curing will be found in order to obtain a desirable bond strength. Maximum allowable pressing duration will be also found, because of thermal degradation of adherend and cured adhesive layer as summarized Figs. 8 and 9.
From empirical data of synthetic thermo-setting resin, such as amino- or phenolic resin adhesive, it was found that a plot of logarithm of reciprocal of suitable minimum pressing duration against reciprocal of absolute pressing temperature gave in good straight line relation, from which bonding activation energy was calculated.
It is interesting to note that the relation of suitable minimum pressing duration with the pressing temperature was able to express with an exponential or hyperbolic formula as equations (9, 11), which would be available for estimating an optimal pressing temperature making production rate greater without loss of bonding strength. However, it is difficult to obtain a general simple formula including board thickness.

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[in Japanese]

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