Baths for activating the surface of plastics to be chemically metal-plated

摘要

1,148,532. Coating with metals. G. OKUNO and C. YAMAUCHI. July 25, 1966 [Aug.6, 1965], No.33317/66. Headings C7B and C7F. Plastics surfaces are sensitized prior to electroless Cu or Ni plating in a bath containing 9À4 to 18À45 mol. /1. sulphuric acid and 0À003 to 0À08 mol. /l. of a metallic ion selected from the group Au, Ag, Pt and Pd. Alternatively if 0À006 to 0À45 mol. /1. of CrO 3 is added to sulphuric acid content may be 5À1 to 18À45 mol. /l. Phosphoric acid in an amount 0À84 to 7À5 mol. /1. may also be added to the solution. The plastics surface may be "A. B. S. ", acrylonitrile - styrene copolymer, polystyrol, polyester, polyethylene, polypropylene, polyurea or polycarbonate. The silver may be in the form of oxide, nitrate, sulphate, chlorate, bichromate, bromide, fluoride, chloride or carbonate, the gold as chloride or sulphate, the palladium as chloride, sulphate or hydroxide, and the platinum as chloride. In an example a copper plating bath comprises (g. /l CuSO 4 , 5H 2 O 50, Na 2 CO 3 25, NaOH 30, Rochelle salt 150, and 100 ml. /1 of 37% formaline. The chemically plated resin is then electro-plated in a copper sulphate bath with a cathode current density of 0À5 A/dm2, dipped in a copper sulphate bath containing a brightening agent at a current density of 3 to 5 A/dm2, electro-plated with nickel in a nickel chloride-sulphate bath containing H 3 BO 3 , butynediol, and sodium 1,3,6- naphthalene trisulphonate, and finally chromium plated in a bath containing CrO 3 and H 2 SO 4 . Several examples are described including an electroless bath containing NiC1 2 6H 2 O, NaH 2 PO 2 and sodium succinate.