Method and apparatus for curtain coating
AssigneeAgfa-Gevaert
InventorsDirk M. Degrauwe, Eduard A. Geleyns
Life of this patent
Estimating the term…
Abstract
Method and apparatus for curtain coating a flexible web by coating the curtain at a width wider than the width of the web. The margins of the web are preserved from being coated by conveying the web in the coating zone over a web supporting roller than does not support the web margins, and by deflecting the unsupported web margins downwardly by means of curtain interceptors that remain in contact with the web under the elastic recovery forces in the web material.
Claims13
In a method of curtain coating a flexible web, which method comprises conveying the web over a web-supporting roller;
- forming a free-falling curtain of coating composition of a width greater than that of the web, said width being maintained by side edge guides in wetting contact with the curtain edges, said curtain being so positioned that its central region falls on a roller-supported region of the web while the opposed side edges of the curtain extend externally of the opposed side boundaries of the web;
- and intercepting and collecting edge portions of the curtain which would otherwise impinge on margins of the web thereby to preserve those margins in uncoated condition, the improvement where the web-supporting roller has a length less than the width of the web and leaves opposite marginal portions of the web unsupported, and said curtain edge portions are intercepted in at least close proximity to the plane of the supported regions of the web at a locus where said marginal portions of the web are slightly downwardly deflected out of said plane against elastic recovery forces thereby induced in the web.
A curtain coater for coating a flexible web, which coater comprises means for conveying a web along a predetermined path through a coating station, said conveying means including a web-supporting roller at that station, said roller having an axial length less than the width of the web whereby at least one side margin of said web projects in unsupported fashion beyond the roller end;
- means for forming at said coating station a falling curtain of coating composition of a width exceeding the supported region of said web and falls onto the web at said coating station;
- side edge guides for contact by the side edges of a said curtain thereby to restrain the curtain from necking-in;
- and means for (a) contacting each such unsupported side margin of said web while passing through said coating station and deflecting against the elastic forces of the web said margin downwardly out of the general plane of the web at said station and for (b) intercepting at least proximate to said general web plane the corresponding end portion of said curtain to prevent the same from otherwise falling upon at least a terminal part of said unsupported web margin and conveying the thus-intercepted curtain composition away from the web margins.
Dependencies are inferred from the claim text.