Zinc chloride free chromium etchant - based on calcium chloride and alkali metal phosphite esp for processing composite printing plates

摘要

The soln. for etching away parts of Cr plated bi- or tri-metal offset printing plates is based on CaCl2 (67%) and contains minor-amts. of HCl and urea, together with 0.2-2% of the alkali metal phosphate, esp. NaN2PO2.H2O being used.