Alkyl Ketene Dimer Wet End Hydrolysis in Alkaline Hardwood Furnish
Alkyl ketene dimer hydrolysis in alkaline hardwood stock converts active sizing wax into unreactive dialkyl ketone, raising chemical costs and felt deposits.
Size Press Starch
Surface Treatment
Aqueous polymeric solutions applied at the wet end exit of a paper machine reinforce surface fiber networks and restrict liquid penetration. Papermakers introduce size press starch during surface sizing to coat exposed paper fibers and fill microscopic surface voids. Enzymatic or chemical modification lowers the viscosity of native corn or potato starch, allowing uniform film formation at high machine speeds.
The dry starch film improves linting resistance, surface strength and ink holdout during printing operations. The functional application excludes wet end internal sizing where chemicals bind to fibers prior to sheet formation.
Fiber Bonding
Penetration depth into the paper web depends on starch solids concentration, nip pressure and sheet dryness before the size press. Surface starch forms hydrogen bonds with cellulose fibers, sealing surface fuzz and increasing Scott bond internal strength. Controlled pickup weight prevents excessive liquid pickup that would require high drying energy in the subsequent dryer section.
Modified starches like cationic or hydroxyethylated variants improve film flexibility, preventing cracking along fold lines during carton converting. Enhanced surface smoothness boosts print crispness in offset and flexographic printing processes.
Operational Limit
High starch solids increase solution viscosity, causing film splitting patterns or misting at elevated machine speeds. Excessive surface starch pick-up reduces web porosity, which retards steam release during high-speed corrugating processes.