Hydrophobic Byproduct
Non-reactive organic compound formed by the decarboxylation of hydrolyzed alkylketene dimer sizing agents exists as a wax-like substance within the finished paper sheet. This dialkyl ketone generated during the papermaking process does not bond to the cellulose fibers and remains mobile. Its presence in high concentrations reduces the friction coefficient of the paper surface, which can cause winding defects and transport issues in printing presses.
Chemical Accumulation
Alkaline sizing systems generate this compound as an unwanted consequence of high water temperatures or prolonged stock retention times in the wet end. When the alkylketene dimer reacts with water rather than the hydroxyl groups of the cellulose, it forms an unstable beta-keto acid. This intermediate rapidly decomposes in the dryer section of the paper machine to yield the dialkyl ketone.
Because this molecule lacks the reactive lactone ring of the original sizing agent, it cannot form covalent bonds with the fibers and instead migrates to the paper surface as a free wax.
Slippage Hazard
Coefficient reduction represents the critical threshold where accumulation affects converting performance. Excessive concentrations of the wax impair toner adhesion and cause feeding failures in high-speed copiers, which limits the allowable amount of hydrolyzed sizing agent in the sheet.
