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.
Styrene Acrylic Ester
Polymer Binder
Synthetic aqueous copolymer dispersions synthesize hard aromatic monomers and flexible acrylate monomers to form durable protective films. Paper coating formulations incorporate styrene acrylic ester as a functional binder to anchor mineral pigments to cellulose base sheets. Styrene units impart high water resistance, hardness and glass transition temperature, while acrylic ester segments provide flexibility and light stability.
The emulsion polymerizes into latex particles that coalesce upon drying into a coherent surface coating. The chemical scope excludes pure styrene-butadiene rubber latices and natural starch binders.
Coating Performance
Latex particle size and monomer ratio govern film formation dynamics and hydrophobic barrier strength. Higher styrene content elevates water repellency and grease resistance, ideal for functional barrier coatings on food packaging boards. The polymer matrix binds calcium carbonate and clay particles together, forming a smooth print surface with minimal dusting during printing runs.
Flexible acrylate chains allow the coated paperboard to bend without cracking along creased packaging edges. Thermal stability ensures the binder does not discolor or degrade during high-speed hot-air drying tunnels.
Substrate Compatibility
Coating solids and surfactant balance must match paperboard surface energy to prevent coat weight variation. Excessively soft polymer formulations can cause block resistance problems, where coated sheets adhere to each other inside tightly wound paper rolls.