In order to reduce pitch trouble of bleached sulfite pulp (softwood : hardwood = 50 : 50) in paper making, some investigations were carried out on the effects of acidification of pulp slurry and addition of aluminium sulfate suggested by Gustafsson et al (1), as well as (NaP0₃) ₆ by Nagrodski et al (2) on reduction of sticky pitch produced during beating process. Contrary to the result of (1), acidification had no effect on the reduction of aluminium sulfate only exerted a bad influence at low pH in the case of the BSP (Fig. 1 & 2), although we also found the similar results to that of (1) in the case of unbleached soft wood sulfite pulp (Fig. 5). While aluminium sulfate had a noticeable effect if pH increased over ea. 5.5 by addition of NaOH (Fig. 3 & Tab. 1). It is supposed that the formation of flocky aluminium hydroxide and its combination with or occlusion of pitch particles may be necessary to the sticky pitch in BSP which chlorinated in bleaching process. The effect was more as addition of alum-inium sulfate increased. Higher temperature should be avoided, since increased the amount of pitch. (NaPO₃) ₆ was also effective, and its effect at 1.5 % addition for pulp was comparable to that of 0.5 % of aluminium sulfate. Addition of aluminium sulfate in beating process had no influence on rate of beating (Fig. 4) and sizing effect (Tab. 2).

View full abstract

When the Edogawa mill of Honshu Paper Mfg Co. constructed SCP plant, the trouble of pollution occured.
Therefore the effect of waste liquor on the aquatic life was investigated.
“ Tolerance Limit-48hr ” or “ Effective Dose 50 %” was measured, using several degrees of concentration of waste liquor, diluted with fresh or sea-water.
Aquatic life was, -
(1) carp, killifish, gold-fish, scenedesmus.
(2) Zoea lavae, tapes philippinarum, goby, green laver, etc.
The result was as follows : -
(1) Safety limit (TLm-48hr) × 0.1 (Aquatic Life Advisory Committee 1955) was × 6, 000 dilution ratio of SCP waste liquor.
(2) Waste liquor, completely spread in the flow of the “ Edogawa ” river, was at least × 33, 000 degrees of dilution.

View full abstract

1) Increment ratio of strength of a paper yarn by twisting is so bigger than that of cellophane that the Japanese paper yarn could be considered a yarn made by twisting fibers arranged lengthwise.
2) The bigger the ratio (P_m/P_b) of lengthwise-machine direction-strength (P_m) to breadthwise strength (P_b) of a raw paper becomes, in other words fibers are better ordered lengthwise, the stronger yarns made by twisting raw papers become.
3) However strength of yarns depends more upon thinness and softness of raw papers, and length, flexibility and strength of raw-fiber, than upon P_m/P_b.

View full abstract