Research Directions in Fiber Recycling of Mixed Office Waste Paper, 1993 Recycling Symposium Proceedings

Edward V. Thompson

The mixed office waste paper stream usually contains a wide variety of polymeric contaminants, among other nonfibrous and filler materials, which must be separated and removed during recycle operations. This talk deals mainly with those polymer materials associated with xero-copied and laser-printed paper, particularly thermoplastic-based toners and styrene-butadiene-based adhesive “stickies.” We will discuss several ongoing research projects associated with our recycle fiber studies program, including: (1)

distinctions between the repulping and flotation behavior of xero-copied and laser-printed test sheets; (2) environmental scanning electron microscope studies of the adhesion and

subsequent “unadhesion” of toner and stickies-type particles to paper sheets; (3) scale-up of laboratory repulping and flotation results to pilot plant and mill situations; (4)

stickies test methods; and (5) novel stickies reformulations which are more easily recycled. We will also discuss

several research areas which we think hold future promise, including: (1) unconventional separation techniques for both toner and stickies-type particles; (2) methods for influencing the particle-size distribution attained after repulping of toner-contaminated paper; and (3) dissolved air flotation, and white-water clarification.