Stickies Control

Abstract

Stickie contaminants are a costly problem for both recyclers of market pulp and the papermakers using it. Increased use of pressure-sensitive adhesives (PSAs) has compounded this problem in recycled furnishes. Stickies have a variety of compositions and vary in the type and amount that are found in the different grades of recycled fiber. Stickies can cause runnability and quality problems, and their variable nature makes them difficult to control. Several methods have been proposed for controlling stickies. Chemical methods involve dispersants, polymers and absorbents. Mechanical methods use screens, cleaners, dissolved air flotation , and washing stages. A new approach to stickies control has been developed that uses esterase-type enzymes to break down the stickies into smaller, less tacky particles. The esterase products provide major improvements in the control of troublesome stickies. Enzyme treatment dramatically reduces the size of the sticky particles and modifies their surfaces so they are less tacky and produce less deposition. These enzymes have been proven to reduce downtime, decrease cleaning chemical costs, and increase machine-clothing life better than historical stickies control technologies. A number of case studies explain the effect of using “Optimyze” in mill situations, producing results such as a 90% reduction in stickies and an increase in brightness across the deinking facility, production performance improvements, and a reduction in the use of cleaning solvents and significant reduction in downtime caused by stickies . The Optimyze product line from Buckman is successfully being used in many mills around the world.