Deinking Toner Ink Containing Furnishes. Part 3. Are Microscopic Ink Particles Formed on Pulping?, 1995 Recycling Symposium Proceedings

John K. Borchardt

Vevolyn G. Lott

Shell Chemical Company

Effective residual ink concentration (ERIC) analysis customarily provides an indication of the presence of microscopic ink particles during newsprint deinking. In this report, ERIC values and brightness measurements combined with scanner-based image analysis indicate whether many microscopic ink particles are being formed when pulping office paper. Styrene-butadiene toners form more microscopic ink particles on pulping than do styrene-acrylate and polyester toners. This is true in the presence and the absence of deinking surfactants. Some deinking surfactants reduce the number of microscopic ink particles even when no reduction in visible ink particles is observed. This suggests that image analysis of visible particle sizes may not indicate ink particle aggregation when microscopic in particles are, in fact, being agglomerated. Contact angle results indicate that good deinking surfactants alter the wettability of toner surfaces making them more hydrophilic.