Water Based Coatings That Keep a Pack inside the Fibre Stream
Water-based dispersion coatings achieve food barrier requirements while maintaining full fiber repulpability and standard mill recovery yields.
Flexographic Curtain Coating
Definitional Method
Application methods involve the delivery of a continuous, falling sheet of liquid coating onto a substrate moving on a flexographic press. Using flexographic curtain coating allows for the application of thick or functional layers at high speeds without the pressure of a traditional nip. It is useful for applying barrier coatings to corrugated board or folding cartons.
Flow Dynamics
The liquid is pumped through a precision die to form a stable curtain that falls under gravity onto the paper surface. This flexographic curtain coating technique eliminates the risk of contact related defects such as orange peel or streaking.
Process Benefits
The absence of a mechanical applicator roll means that the coating can cover irregular surfaces and fluted structures without crushing them. Since the system is non-contact, flexographic curtain coating can be used to apply sensitive materials that might otherwise be damaged by shear forces. It also allows for extremely uniform coat weights across the entire width of the web.
Maintaining a stable curtain requires careful control of the liquid viscosity and surface tension to prevent the film from breaking. This method is increasingly popular for applying water based grease and moisture barriers in sustainable packaging production.