PLASTICS MATERIALS HAVING ELECTRODEPOSITED METAL COATINGS

摘要

1,249,309. Electro- and electroless-plating plastics. CIBA (A.R.L.) Ltd. May 22, 1969 [May 27, 1968], No.25253/68. Heading C7B and C7F. A plastics article is coated with an adherent, highly stressed, electro-deposited film of Cu or Ni under an average stress in tension of at least 2,000kg./sq. cm. For Ni plating, the bath may contain NiCl 2 and NiSO 4 with H 3 BO 3 , CoSO 4 and Na formate, the ratio of Cl to SO 4 ions being greater than 1 and/or the pH not below 5. For Cu plating, the bath may contain CuCN, NaCN and NaOH. The Ni film may overlie an electrolessly deposited film of Ni or Cu which in turn overlies an electrolessly deposited film of Pd or Ag; the Cu film may overlie an electrolessly deposited film of Pd or Ag. The dull highly stressed film may underlie a bright lightly stressed, electrodeposited film of Ni, Cu, Ag, Pd or Au under an average stress in tension of not more than 1500 kg/sq cm, which, when of Ni, may in turn underlie an electro-deposited film of Cr, Cd, Sn, Pb, Ag or Au. Preferably the average thickness of the lightly stressed film with any subsequent electrodeposited film should not exceed ten times that of the highly stressed film. The plastics may be a thermoplast, e.g. a polyolefine, polymethacrylate, polycarbonate, an ABS copolymer, a polyoxymethylene or polysulphone, or a thermoset, e. g. a cured epoxy resin, an aminoplast or a phenoplast with or without an inert filler, such as calcined china clay (molochite), TiO 2 , or glass or polyester textile fibres. The filled thermoset plastics may be a glass fibre laminate electro-plated with Ag, Pd or Au, useful for printed circuits. The plastics article may be chemically etched by immersion in K 2 Cr 2 O 7 - H 2 SO 4 - H 2 O mixture, then sensitized by immersion in an aqueous solution of SnCl 2 and HCl, prior to electroless plating in (1) an aqueous solution of PdCl 2 and HCl, or an ammoniacal AgNO 3 solution containing an aldehyde, then in (2) an aqueous solution containing NiSO 4 , MgSO 4 , Na citrate and acetate, and NaH 2 PO 2 , or a mixture of aqueous solutions: containing CuSO 4 , NiCl 2 and hydrazine sulphate, and containing NaOH, Rochelle salt and Na 2 CO 3 .