Effectiveness of retention aids for pitch control in TMP newsprint manufacture. Part I: Low shear

How effective are retention aids for retaining dispersed wood resin? This question was addressed in a lab study using a Dynamic Drainage jar and a headbox furnish from a TMP newsprint mill that employed no retention aids. Seven different retention aid systems were investigated. Performance was determined from the reduction in concentration of dispersed extractives particles, measured with a hemacytometer. The results give an overview of the relative effectiveness of the various retention aid systems in this TMP furnish at simulated slower paper machine speeds.