Curtain coating

from Wikipedia, the free encyclopedia

Curtain coating (also: curtain coating ) is a process for applying barrier layer coatings and clear top layers or pigmented standard coatings on flat films, in which the coating is applied by passing the panel under a falling "curtain" of the coating material.

Curtain painting can be used to coat endless sheet metal strips, but also fairly flat individual pieces such as sheet metal parts, circuit boards or skis in a particularly uniform manner. By measuring the width of the curtain, possibly also by continuously returning the material of the curtain falling next to the workpiece, it is possible to coat with particularly little waste. In special cases

For some years now, thermal paper and inkjet paper have been coated with curtains - technically speaking: painted . Multi-layer coatings are possible in one pass through a multi-layer curtain (a single layer of liquid). It is possible to apply 2 components that govern each other.

Since the 1970s, curtain coating has been used in the industrial production of photographic material to create multiple layers on the substrate. The advantage of the curtain coating is the high consistency of the layer thickness of the application, even if the substrate is somewhat uneven. This also makes it possible to produce photo paper with a linen structure.

Surface tension and the curtain layer, which is very thick compared to molecular layers, makes them expandable and compressible, which makes it possible to paint concave or convex parts to a certain extent. The light curtain reacts sensitively to air currents, especially eddies and shocks, as well as to electrostatic charges, which can cause attraction, repulsion and discharge.

When coating agents are applied to paper by roller or squeegee, the proportions between the liquid supply, application tool and paper determine the "self-dosed" application quantity. With curtain coating, however, the volume flow is pre-dosed very precisely and results in a very constant (<± 1%) thick application when the substrate passes at a constant speed.

Web links

Commons : Curtain coating  - collection of pictures, videos and audio files