The problems caused by stickies are many and varied and can occur at practically every stage in the papermaking and paper conversion chain including printing. Finding a suitable way to treat them can be difficult..
The problem is complicated by the fact that there are two types of stickies:
(1) Primary stickies, insoluble components that are tacky under normal conditions and are present in the incoming recycled paper and coated broke, e.g., hot melts or pressure sensitive adhesives, inks, waxes, plastics, synthetic adhesives, resin size, wet-strength resins, and binders; and
(2) Secondary stickies, composed of the soluble components of adhesives and chemicals used in papermaking and converting. Secondary stickies are formed as a consequence of sudden changes in wet end chemistry, temperature or pH, when they react to produce insoluble or gel-like tacky particles. They can be more difficult to handle than primary stickies.
The problems caused by these tacky impurities are all too familiar. Deposits occur on stationary parts of a processing system such as pipes and chest walls and in the approach flow system. This includes the headbox itself due to the adhesive character of these materials. Deposits primarily influence moveable parts such as wires, felts, or rolls. Stickies will end up in the final paper produced and cause quality problems aesthetically and in its subsequent use.
Deposits within the paper machine can cause:
Web breaks due to weak spots and localized sticking to moving rolls Picking of fibers
Lengthy nonproductive cleaning times due to build-up on wires, felts, rolls & doctor blades
Converting problems due to adhesion between sheets. Problems during unwinding of a reel causing breaks, surface blemishes, or misfeeds in sheet-fed process.
SKHZYE-DGM93 is an enzyme preparation intended for use in reducing stickies in recycled pulps. Properly applied microbial enzymeâ€“based products can enhance the release of stickie particles from the fiber surface and facilitate its removal by flotation.