Abstract

The present invention relates to the adhesional pretreatment of plastics surface prior to their metallization by chemical or electrochemical methods and may be used in those industrial fields where decorative or functional metallic coatings on top of the plastic surfaces are needed. The purpose of the proposed invention is a high-quality adhesional pretreatment of plastic surface prior to metallization. The purpose is achieved by treating the plastic before to etch it 5-15 min at 50-70° C. in the alcaline permanganic solution containing 1-3M NaOH and 0.1-0.5 M permanganate ions and acidic permanganic etching solution additionally contains 0.5-8.0 M of copper nitrate and the etching is performed at room temperature during 5-60 min.

IPC Classes  ?

• C23C 18/24 - Roughening, e.g. by etching using acid aqueous solutions
• C23C 18/32 - Coating with one of iron, cobalt or nickelCoating with mixtures of phosphorus or boron with one of these metals
• C25D 5/56 - Electroplating of non-metallic surfaces of plastics

Abstract

Provided are chrome-free adhesion pretreatment processes for use on a variety of reinforced or unreinforced plastics and polymers, such as polyimides, polyetherimides and polyvinylchloride. The pretreatment process can be performed in a combination of two sequential operations, which includes treating with a first solution containing nitric acid and subsequently treating with a second solution that includes sulfuric acid and periodate ions. Alternatively, the pretreatment process can be performed by treatment with a single combined composition that includes nitric acid, sulfuric acid, and periodate ions. The pretreatment processes, either done in two separate solutions, sequentially, or in one combined solution, produce an adherent surface for further metallization of the article, with adhesional values of the metal layer higher than those achieved using conventional chromic acid pretreatment processes.

IPC Classes  ?

• C23C 14/02 - Pretreatment of the material to be coated
• C23C 18/20 - Pretreatment of the material to be coated of organic surfaces, e.g. resins
• C25D 5/56 - Electroplating of non-metallic surfaces of plastics
• C23C 16/02 - Pretreatment of the material to be coated
• C23C 18/24 - Roughening, e.g. by etching using acid aqueous solutions
• C23C 4/12 - Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
• C23C 14/20 - Metallic material, boron or silicon on organic substrates
• C23C 14/34 - Sputtering
• C23C 18/16 - Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coatingContact plating by reduction or substitution, i.e. electroless plating