Some characteristics of several different kinds papers

Abstract

(1) Some physical characters of several different kinds of paper which relate to the silkworm rearing were measured. The measured characteristics were (a) thickness, (b) weight for unit area, (c) density (d) smoothness of smooth side and of rough side, (e) aerial permeability, (f) water absorption ability, (g) water-vapour absorption ability, (h) water-vapour permeability (i) water evaporation rate in linear part, and (j) CO2-gas permeability. The kinds of paper were (1) Japanese common paper, (2) popular paper in Japan, (3) news-paper used in Japan, (4) hatlon paper, (5) paper for silkworm-rearing, (6) egg-card for silkworm, (7) thick paper, (8) cellophan paper, and (g) paraffin paper. The water vapour permeability and the CO2-gas permeability of (10) cotton cloth in dry state, of (11) wetted cotton cloth, and of (12) no substance to cover were measured, too. The measured values were shown in Table 1.(2) Both the cellophan paper and the paraffin paper have no permeability for the air and the CO2-gas.(3) The wetted cloth, having been controlled by water contained in it, shows different degrees of aerial permeability and of CO2-gas permeability.(4) The cellophan paper has considerable permeability for water-vapour, but no ability for other gases (air, CO2).(5) Paraffin paper has almost no permeability for the water-vapour as well as for other gases.(6) The water-vapour absorption ability (A) of a series of paper made of wood fibers is proportional to n power of each own areal weight (W), viz. A=kWn. (See Table 2).(7) The relation between the sheets of paper (S) and the water-vapour permeability (T) is shown by following functional type: T=Tc+ae-nS. (See Table 3)(8) The water-vapour permeability of a kind of paper is proportional to the difference of the vapour pressure between the one side and the other side of the paper (See Fig. 1).