Homogeneous composition for making a film of gold onto a substrate, process of making such film of gold, gold thiolate and process for preparing thereof

摘要

A homogeneous compsn. for forming, on firing, a film of precious metal (I) selected from one or more of platinum, palladium, gold and silver, onto a substrate (II). The compsn. comprises: (i) polymeric resin (III); and (ii) a soln., in water and a co-solvent (IV), of a thiolate of (I). The compsn. contains 3-22 wt.% of (I) as the thiolate. (III), (IV) and the thiolate are such, that as the compsn. (on a substrate (II) dries and is progressively heated in firing, the water evaporates to leave a homogeneous compsn. of (III) and thiolate in the cosolvent (IV); subsequently, (IV) evaporates to leave a homogeneous compsn. of the thiolate in (III); finally, the thiolate decomposes to (I) while the resin (III) violatilises. Firing is carried out at 460-900 deg.C. The compsn. produces a bright film on firing. The compsn. can opt. contain precious metal powder or insoluble precious metal cpd. to produce a burnished film on firing which is subsequently burnished. Alternatively, the compsn. opt. contains an insol. matting agent to produce a self-burnishing film on firing.