Aluminium sheet with rough surface
AssigneeAlcan International Limited
InventorsPeter Karl Ferdinand Limbach, Martin Philip Amor, Jonathan Ball
Life of this patent
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Abstract
Aluminium sheet suitable for use as a lithographic plate support has a surface that is uniformly rough by virtue of: a rippled topography having an aspect ratio of at least 1.3 on a sale of 5-200 μm; and a superimposed pitted structure on a scale of 1-20 μm. A method of making the aluminium sheet involves pack rolling two aluminium ribbons to generate facing surfaces having the transverse rippled structure; followed by a small amount of a conventional roughening or graining treatment to develop the pitted structure.
Claims5
A method of making a sheet having a roughened surface, starting from two or more ribbons of aluminium, by the steps of:
- a) Pack rolling the ribbons to provide a pack of two or more sheets and separating the pack into individual sheets each having a matt surface that faced another sheet of the pack during rolling, and
- b) Graining the said matt surface of the sheet.
A method of making a lithographic plate support, starting from a ribbon of aluminium, by the steps of:
- a) Pack rolling the ribbon to provide a pack of two or more sheets and separating the pack into individual sheets each having a matt surface that faced another sheet of the pack during rolling, and
- b) Graining the said matt surface of the sheet to an extent sufficient to firmly bond to the grained surface a layer of an organic material.
Dependencies are inferred from the claim text.