Function/Description
With
knife systems, the coating paste is applied onto the carrier or the substrate with a knife or blade. Depending on the desired
effect to the knife is countered by a roller, platen or nothing at all; thereby roller knives, platen knives and air knives
are distinguished. The knife bar of modern coating plant is equipped with several coating knives and is changeable according
to the revolver principle. This facilitates a quick change of the knives, especially of the roller and the air knife. All
application systems are equipped with either manually or powered adjustable side scrapers.
In some cases, the side
scrapers are completed to a closed paste basin with a front plate, which is necessary especially when low-viscous coating
pastes are concerned. Depending on the thickness of the coat to be applied, on the way of the knife's configuration and the
viscosity of the paste, knives of different profiles are used.
With knives, the thickness of the coat is defined by:
- Distance between knife
and substrate
- Kind of the substrate
to be coated
- Kind and form of the
knives
- Angle of the knife
- Position of the knife
- Viscosity of the paste
- Speed of the web
For
air knives it is especially the web tension that influences the thickness of the coat.
Variation of the Coating Weight
- Roller knife 10 to
1250 g/m²
- Air knife 5 -6 to
60 g/m²
Range of Viscosity [mPas]
- Paste(1000) 100 -
50 000
- Foam 10 000 - 25 000
- Air knife 5 - 10 000
Typical Applications
- Protective Clothing
- Tarpaulins for trucks
- Floor coverings
- Roof membranes
- Artificial leather
- Airbags
- Anti slip mats
