Foam coating is an established technology in the textile industry to apply chemicals or dispersions on textiles. It is a well-known technique also in plastic film production.
In foam coating process, foam is used as a carrier phase for the coating material. The liquid, containing coating solids and foaming agents, is mixed with air in a foam generator. The foam normally contains
approximately from 80% to 95% of air. The use of high air content makes it possible to apply even, very thin nanostructured and antimicrobial layers. The smallest applied structures are in the size-range from 1 Ám or even below with nanocellulose and inorganic nanoparticles and up to 4-5 Ám with dispersions with higher solids. The foam coating can be carried out as non-contact application alone or followed by a smoothening nip or vacuum that will improve the adhesion or
saturation of coating into the substrate.
Foam coating applicator. Appearance of the nanostructured CNF-foam coated samples on a nonwoven substrate.