Method of forming a metallic thin film by electroless plating on a vinylidene chloride undercoat

Claim 1

A method of forming a metallic thin film on a plastic substrate by electroless plating which consists essentially of (a) providing on a surface of the substrate an undercoated layer of a vinylidene chloride copolymer selected from the group consisting of vinylidene chloride-vinyl chloride copolymers and vinylidene chloride-acrylonitrile copolymers, the vinylidene chloride copolymer having a softening point of 100° to 200° C and a degree of polymerization of at most 1000 and having a vinylidene chloride content of 8 to 98% by weight, (b) subjecting the surface of the layer to surface activating treatment of (1) sensitizing the surface with a sensitizer solution containing hydrochloric acid and stannous chloride followed by activation with an activator containing a noble metal ion, or (2) contacting the surface with a catalyst containing stannous and noble metal ions followed by contacting the surface with an accelerator, and (c) subjecting the resulting surface to electroless plating in an electroless plating bath containing 0.02 to 0.6 mol/l of cobalt ion, 0 to 0.02 mol/l of nickel ion and 0.03 to 0.4 mol/l of hypophosphite ion, optionally with a complexing agent, pH buffering agent and pH regulator, whereby metal ions are deposited on the surface.

Claim 2

A method of forming a metallic thin film on a plastic substrate by electroless plating which consists essentially of (a) providing on a surface of the substrate an undercoated layer of a vinylidene chloride copolymer selected from the group consisting of vinylidene chloride-vinyl chloride copolymers and vinylidene chloride-acrylonitrile copolymers, the vinylidene chloride copolymer having a softening point of 100° to 200° C and a degree of polymerization of at most 1000 and having a vinylidene chloride content of 8 to 98% by weight, (b) subjecting the surface of the layer to surface activating treatment of (1) sensitizing the surface with a sensitizer solution containing hydrochloric acid and stannous chloride followed by activation with an activator containing a noble metal ion, or (2) contacting the surface with a catalyst containing stannous and noble metal ions followed by contacting the surface with an accelerator, and (c) subjecting the resulting surface to electroless plating in an electroless plating bath containing 0.02 to 0.6 mol/l of cobalt ion, 0 to 0.02 mol/l of nickel ion and 0.03 to 0.4 mol/l of hypophosphite ion, optionally with a complexing agent, pH buffering agent and pH regulator, whereby metal ions are deposited on the surface.