| 摘要 |
A detergent cleaning composition comprises (g./1.) sodium isopropyl naphthalene sulphonate 3, sodium sulphate 1, sodium tripolyphosphate 14, sodium metasilicate 5, and tetrasodium pyrophosphate 27 in water.ALSO:Through holes in a printed circuit have their lateral surfaces coated with copper by electroless deposition using a solution comprising a water soluble copper salt 0.002 to 0.15 moles/1., a copper complexing agent for cupric ion 0.5 to 2.5 times the moles of the copper salt, alkali metal hydroxide to give a pH of 10.5 to 14, formaldehyde 0.06 to 3.4 moles/1., and a complexing agent from 0.00002 to 0.06 moles/1. The insulating base of e.g. nylon, polystyrene, melamine or epoxy resin may be first sensitized with stannous chloride followed by palladium chloride or a mixed bath containing tin ions with palladium, platinum, gold, osmium, rhodium, or indium. In a specific example, a panel comprising an insulating base clad with copper foil is given a positive pattern with etch resist ink, the panel etched to remove the exposed copper foil, the resist removed, and the whole coated with acid resist, holes are punched in the panel, the whole sensitized, and the acid resist removed. Copper is then deposited by the electroless process. The printed circuit is formed by photographic techniques. Additional metal e.g. nickel, gold, silver or rhodium may be electrolessly deposited or electroplated on the panels. An electroless gold bath may contain a hypophosphate ion as a reducing agent. |
