紙の物理的性質におよぼす繊維間結合面積およびヘミセルロースの影響

抄録

Birch bleached sulphite pulps extracted with 1-5% sodium hydroxide solutions were beaten by Lampen mill or Tappi standard test beater. Beating rate and tensile or bursting strengths of the pulp at the equal freeness decrease with the amount of hemicelluloses extracted (Table 1, Fig. 1 and 2). The reason seems to be that water retention value of pulp beaten at the equal freeness and fiber bonded area in the dried sheet (shown as specific scattering coefficient) decrease with the amount of hemicelluloses extracted (Fig 3). However, the water retention value, especially specific scattering coefficient relates closely with tensile or bursting strengths of the sheet, irrespective of the amount of extracted hemicelluloses (Fig. 4 5 and 6).
The pulp beaten in aluminium sulphate solution is poor in beating rate and bursting strength compared with the pulp beaten in water. On the other hand, the uronic acid-rich pulp bleached with sodium chlorite (Table 2) is easier to swell by beating and higher in bursting strength at the equal freeness compared with the pulps bleached by a conventional 3 stages process (chlorination, caustic extraction, hypochlorite bleaching). In all these pulps, however, specific scattering coefficient relates with the tensile or bursting strengths (Fig. 7 and 8). Speciffic scattering coefficient relates also with air permeability (Fig. 9 and 10).
The tearing strength and the wet tensile strength of the pulps treated with sodium hydroxide solutions are higher than those of the original pulp at the equal specific scattering coefficient (Fig. 11 and 12) This result shows probably that the bonding strengths at the equal bonded area of these pulps are not invariably constant.
Sheet density does not relate with specific scattering coefficient in the case of pulps varied in hemicellulose contents (Fig. 13).