Overview of the Chemical Nature of Deposits/Stickies in Mills Using Recycled Fibre, 1997 Recycling Symposium Proceedings

Problems associated with stickies were documented in eleven newsprint, three fine paper, four board and two tissue mills using recycled fibre. Samples of deposits or contaminants were also collected from various locations in mills and from finished products. Chemical compositions of some deposits were determined using a recently-developed analytical scheme. In addition, FTIR spectroscopy with a miniature diamond anvil cell/beam condenser accessory was used for rapid identification of dirt specks and deposits and of fractions obtained from them. In the newsprint mills examined in this work, the bulk of deposition occurred in the press section; the fine paper mills most often experienced spots in the finished paper, whereas in the board mills, deposits on dryer fabrics were particularly prevalent. In addition, contaminants on forming fabrics were found in all types of mills. Spots on these fabrics were largely organic in nature, and sometimes consisted of pure polymeric material, originating mainly from pressure-sensitive adhesives and coating binders. In the newsprint mills, as the paper progressed from the forming to the press section, fibres and inorganics were carried with the deposits; in the finished product, spots were often mixtures of fibres and inorganics bound together by a small amount of hydrophobic material.