Demetallizing procedure
AssigneeBeckett Technologies Corp.
InventorD. Gregory Beckett
Life of this patent
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Abstract
Selective demetallization of an etchable metal layer supported on a polymeric material or other microwave transparent material, or a self-supporting etchable metal layer, particularly aluminum of thickness at least about 1 micron adhesively joined to a flexible polymeric material substrate, is described. A web of polymeric material bearing the etchable metal layer, or an unsupported etchable metal layer, has a pattern of etchant-resistant material first applied and then the web is immersed in and passed through a bath aqueous etchant, particularly hot aqueous sodium hydroxide solution, for a time at least sufficient completely remove the etchable metal from non-protected areas of the web. The demetallized web is washed and dried. Specific structure incorporating the selectively demetallized etchable metal layer also are described.
Claims23
A continuous method of effecting selective demetallization of a layer of aluminum having a thickness of about 1 to about 15 microns supported on a microwave transparent web of flexible polymeric material, which comprises:
- providing said microwave transparent web as a continuous web and conveying said continuous web from a reel thereof successively through an etchant solution-applying zone, a washing zone and a drying zone,
- providing said microwave transparent web with a pattern of etchant-resistant material on said aluminum layer corresponding to a desired pattern of non-etched aluminum prior to said continuous web entering said etchant solution-applying zone,
- continuously driving said microwave transparent web with said pattern of etchant-resistant material thereon in an immersed condition through a bath of aqueous etchant material which is aqueous sodium hydroxide having a temperature of about 10.degree. to about 90.degree. C. and a strength of about 0.1 to about 10 normal and conveying said microwave transparent web through said etchant solution-applying zone for a period of time of at least about 0.5 seconds per micron thickness of said aluminum layer and at least sufficient to effect complete removal of said aluminum layer not covered and protected by said pattern of etchant-resistant material,
- wiping said aqueous etchant solution from the surfaces of said web before said web leaves said etchant solution-applying zone,
- contacting said web with wash water in said washing zone to remove residual etchant solution therefrom,
- wiping wash water from the surfaces of said web before said web leaves said washing zone, and
- drying said web in said drying zone.
A method of effecting selective demetallization of a self-supporting aluminum web having a thickness of about 1 to about 15 microns and first and second sides to form an element having a plurality of apertures through said aluminum, which comprises:
- applying a pattern of etchant-resistant material to both said first and second sides of said aluminum web in register and corresponding to a desired pattern of non-etched aluminum in the element and comprising a continuous aluminum web having a plurality of apertures therethrough,
- repeatedly contacting said aluminum web with an aqueous etchant material comprising an aqueous solution of sodium hydroxide by immersing said aluminum web in and passing said aluminum web through a bath of said aqueous etchant material having a temperature of about 10.degree. to about 98.degree. C. and a strength of sodium hydroxide of about 0.1 to about 10 normal for a period of time of at least about 0.5 seconds per micron thickness of said aluminum web and at least sufficient to effect complete removal of said aluminum from areas of said aluminum web not covered and protected by said pattern of etchant-resistant material and to form apertures through said aluminum web,
- removing said aluminum web from said bath,
- washing spent etchant solution from the removed aluminum web, and
- drying the washed aluminum web to provide said element comprising a self-supporting aluminum having a plurality of apertures therethrough.
Dependencies are inferred from the claim text.