Abstract
Deresination effect of surfactants containing the condensate of sodium naphthalene sulfonate with formalin was evaluated during hot alkali refining in a conventional multi-stage refining process of sulfite pulp. When mixtures of Tamol N (I) with polyoxyethylene nonylphenyl ether (n=9) (II) were employed in the refining of sulfite pulp obtained from fresh softwood, synergistic deresination effect was observed in the mixing ratio of 1:1 to 1:2 (i.e. (1) 50 to 33%, (II) 50 to 67%.) Seven kinds of condensate of sodium naphthalene sulfonate (or sodium alkyl naphthalene sulfonate) with formalin were mixed with (II), and the mixtures were evaluated similarly. In the case of (I), the result was again very good. But with two condensates, the results were doubtful and with four condensates, none of mixing effect was obtained. When mixtures of (I) with (II) were applied in the refining of hardwood sulfite pulp, the deresination effect was poor on the contrary to that for softwood pulp.
