Agfa-gevaert Ag

Agfa-gevaert Aktiengesellshcaft

Kurt Browatzki

Hans Frenken

Heinrich Bussmann

Gunther Koepke

Johannes Sobel

Wolfgang Schweicher

G/u/ Nther Koepke

Webs coated with several layers, of which the lowermost or uppermost layer contains an instant hardener, may be produced in a single operation by curtain coating using a V-coater when the hardening layer is guided at the negatively inclined sliding surface of the V-coater while the other layers are guided at the opposite sliding surface of the V-coater and the hardening layer is combined with the remaining layers at coating edge to form a layer packet which is applied as a free-falling curtain to the web to be coated.

Curtain coating process

A process for the multiple coating of webs which are continuously moving past a coating point, using coating apparatus according to the bead coating process is carried out such that any number of comparatively high viscosity layers is arranged above an accelerating layer which lies below the layers and has a viscosity range of from 1 to 20 mPas and a layer thickness of from 2 to 30 .mu.m. A very small gap width of from 100 to 400 .mu.m is selected between the sliding surface coating head and the web to be coated and only a low reduced pressure is applied under the coating head. By this process, coating rates of 400 m/min and more may be achieved with a good coating quality.

Process for the multiple coating of moving webs

A process for the multiple coating of objects or webs which are continuously moving past a coating point, using coating apparatus according to the curtain coating process. This process is carried out such that any number of comparatively high viscosity layers is embedded between an accelerating layer which is positioned below the layers and has a viscosity range of from 1 to 20 mPas and a layer thickness of from 2 to 30 .mu.m, and a spreading layer which is positioned above the comparatively high viscosity layers and has a viscosity range of from 1 to 10 mPas and a layer thickness of from 5 to 20 .mu.m. By the curtain coating process, coating rates of 400 m/min and more may be achieved with a good coating quality.

Process for the multiple coating of moving objects or webs

The stabilization of free-falling liquid curtains (4) in the coating of objects or webs (5) using curtain coaters is considerably improved by the use of curtain holders (9) from which an additional auxiliary liquid (11) issues towards and combines with the curtain (4), for laterally guiding the free-falling curtain (4) formed at the coating edge (3) of the coater. Triangular liquid bridges (14) are thus formed between the curtain (4) and the curtain holders (9) from the coating edge (3) to the point where the curtain (4) impinges on the layer support (5). The curtain holders (9) consist of tubular hollow bodies with a delivery spout (10) and a distributing passage (12) for the liquid (11) and an exit slot (13) or of a porous tubular material without any exit slot (FIG. 3).

Process and an apparatus for stabilizing free-falling liquid curtains

The invention relates to an apparatus and process for simultaneously coating several layers to moving objects, particularly webs, whereby at least two liquid coating materials issue over the width of V-shaped sliding surfaces or above following sliding surfaces are delivered to the two sliding surfaces which are arranged in the form of a V and which form a discharge edge above the objects or web to be coated, flow down the underside of the V-shaped sliding surfaces, combine at the end of the sliding surfaces to form a multiple layer film of liquid which is deposited in the form of a free falling curtain onto the objects or the web of layer support material.

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Leverkusen, Germany

Kurt Browatzki