Optimization of process conditions for electroless copper plating on polyester fabric

Abstract

The copper-coated polyester fabric can be used to prepare electromagnetic shielding materials. At present, electroless copper plating mainly using formaldehyde as the reducing agent. But the stability of the bath is poor and it is also volatile and toxic. Using hypophosphite as reducing agent has more advantages for its stability and the plating process does not release any toxic gases. In this paper, The copper-coated polyester fabric was prepared by electroless plating with the sodium hypophosphite as reducing agent. The roughening condition before plating and the deposition process were optimized through orthogonal test. The surface resistances of conductive polyester fabrics, the deposition rate and the coating adhesion were investigated respectively. The optimum roughening conditions obtained are as following: sodium hydroxide concentration of 250g/L; temperature 70 D; time 15min, and the lightweight rate of the plating layer is 0.43% under the experimental conditions. The optimum conditions of electroless copper plating using sodium hypophosphite as reducing agent are: copper sulfate 8g/L; nickel sulfate 1.0g/L; sodium hypophosphite 35g/L; citric acid 20g/L; boric acid 30g/L; pH 9.0; temperature 75D. With these conditions, the deposition rate reaches 1.274g/(m2·min) and the uniform and compact copper layer with excellent electro-conductivity was obtained.