Dispersion Barrier Coating Mechanics under Crease Stresses in Flexo Converting
Flexographic dispersion barrier coatings retain water and grease resistance under crease stresses only when coating elongation capacity matches board strain.
Polybutadiene Latex
Polymer Binder
Synthetic elastomeric emulsions added to paperboard coating formulations improve flexibility and surface strength in demanding packaging applications. Incorporation of polybutadiene latex provides high elasticity and strong binding affinity for mineral pigments such as calcium carbonate and kaolin clay. The synthetic rubber polymer forms a cohesive matrix that binds pigment particles to base cellulose fibers during high-speed coating drying.
This chemical additive is utilized in coated folding boxboard and liquid packaging board formulations, but is omitted from uncoated paper grades.
Coating Flexibility
Coated paperboard subjected to tight radius folding exhibits micro-cracking along scorelines when formulated with rigid binders. Incorporating polybutadiene latex into the coating layer absorbs mechanical stresses during creasing and folding, preventing surface flaking and pigment dusting. The low glass transition temperature of polybutadiene polymers maintains coating film ductility under ambient and refrigerated storage conditions.
Coated board retains smooth visual appearance and intact barrier properties across folded carton edges.
Surface Performance
Binder selection influences ink acceptance and dry pick strength on high-speed offset lithographic printing presses. Formulations containing polybutadiene latex improve web offset printing runnability by resisting high ink tack forces without surface picking. The hydrophobic nature of synthetic rubber polymers enhances water resistance, preventing wet rub damage during flexographic printing with water-based inks.
Paper mills optimize latex addition rates to balance sheet brightness and print compressibility. Utilizing elastic synthetic binders ensures superior surface durability for premium printed packaging.