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US 5,304,298 AGranted
Process for roughening aluminum or aluminum alloys
AssigneeHoechst Aktiengesellschaft
InventorMichael Brenk
Life of this patent
Estimating the term…
Abstract
A process for roughening aluminum or aluminum alloys useful as support material for printing plates, in which process two electrochemical roughening steps are carried out in direct succession and are followed by a pickling step. Printing plates are produced from this support material by coating with light-sensitive coatings, which printing plates, when exposed and developed, give corresponding printing formes of very uniform topography, high run stability and good damping agent supply.
Claims21
A process for roughening an aluminum or aluminum alloy support material useful for printing plates comprising
- a) a first electrochemical roughening step carried out in an electrolyte containing an acid selected from the group consisting of hydrochloric, nitric, and sulfuric acid;
- and chloride or nitrate ions,
- b) a second electrochemical roughening step following step a) carried out in an electrolyte containing an acid selected from the group consisting of hydrochloric, nitric, and sulfuric acid;
- and chloride or nitrate ions, and in which the concentrations of the additives are the same as or different from those in the first electrochemical roughening step, and
- c) a purely chemical pickling step in an acid or alkaline bath following step b), which removes undesirable layers which make the surface of the support non-uniform and dark.
2 more elements
Dependencies are inferred from the claim text.