Abstract
Builders were mixed with binary surfactant mixtures comprising anionic and nonionic surfactant to find the best mixing ratio for the deresination of hardwood sulfite pulp, and the deresination effect of built agents prepared on the basis of those results was evaluated. The effect of small amounts of solvents mixed with surfactant mixture was also studied.
The best mixing ratio for a mixture of sodium dodecylbenzene sulfonate (I) with polyoxyethylene nonyiphenyl ether (n=9) (II) in the mixing ratio of 1:1 is sodium tripolyphosphate (III) 25% sodium sulfate (IV) 50% or carboxymethyl cellulose (V) 10% based on the amount of surfactant mixture, respectively. In the case of a mixture of secondary alkyl sulfate (VI) with (II), the mixed effect of builders is less as compared to that for a mixture of (I) with (II).
Best deresination effect is obtained with the built agents comprising (I) 1 part, (II) 1 part, (III) 0.5% part and (V) 0.2 part, or (I) 1 part, (II) 1 part, (III) 0.5 part and (IV) 0.5 part. These built agents show excellent effectiveness under the addition in amounts of above 0.1% (dry pulp basis), although they are inferior to (II) below 0.1%.
Improved deresination effect is also observed, when xylene or tetralin is incorporated to a mixture of (VI) with (II) in an amount of 20%, based on surfactant mixture.
