Measurement of stickies (Macro, Micro and Potential Secondary Stickies)

Abstract

Contaminants from synthetic polymers such as plastics, coatings, adhesives and waxes remain one of the biggest challenges for papermakers using recovered fibre. These contaminants are called “stickies” because they stick to paper machine felts and wires leading to operating problems, reduced productivity and defects such as holes and dark spots in the paper. Through a survey conducted by the CSIR, the South African paper recycling industry identified several shortcomings of existing methods for measurement of stickies, and has expressed the need for quick and simple methods that could be easily implemented in a mill environment. The consequence of "inadequate methods" has been poor process monitoring and the inability to fore-see stickies-related problems before they occurred. This resulted in a rather reactive approach to dealing with these problems. As with all testing procedures, the criteria for any measurement must include a high degree of precision and repeatability. However, in a mill environment, operator time and ease of implementation must also be considered, and more often than not, a compromise is required. In response to this need, the CSIR developed quick and simple methods for routine measurement of all types of stickies (macro, micro, and potential secondary stickies. The applicability of the methods was demonstrated during stickies audits carried out at a newsprint and packaging mill.