Dispersion Barrier Performance in Folding Boxboard Substrates
Aqueous dispersion barrier performance depends on wet coat weight uniformity, film drying coalescence, and creasing matrix geometry that prevents score line cracking.
Styrene-Butadiene Rubber Emulsion
Binder Chemistry
Synthetic latex produced from the polymerization of styrene and butadiene provides high adhesive strength and water resistance for paper coatings. A styrene-butadiene rubber emulsion acts as a binder that holds pigment particles together and anchors them to the board surface. This material is widely used in the production of coated fine papers and high quality packaging grades.
It contributes to the overall stiffness and gloss of the finished product.
Rheological Effect
The addition of the liquid latex influences the flow behavior of the coating colour as it passes under the metering blade. A styrene-butadiene rubber emulsion helps stabilize the mixture and prevents the separation of solids at high shear rates. This ensures a smooth and defect free application even at high machine speeds.
Printability Benefit
Enhanced ink holdout and surface strength allow for sharper images and more vibrant colours in offset printing. Because the styrene-butadiene rubber emulsion is hydrophobic, it improves the water resistance of the paper surface, which is required for the lithographic process. It also provides the elasticity required to prevent the coating from dusting or picking during the print run.
The ratio of styrene to butadiene is carefully balanced to achieve the desired level of hardness and flexibility for the specific grade of paper.