GB1180583A - Metal Plated Plastics and process therefor - Google Patents

Abstract

1,180,583. Treating polyolefins. UNION CARBIDE CORP. 10 March, 1967 [10 March, 1966], No. 11345/67. Heading C3P. [Also in Division C7] Metal-plated plastics material whose coatings are strongly adherent, with peel strengths of 5 lb./in. or more are produced by oxidizing the surface of an at least partially crystalline aliphatic poly-α-olefin containing tertiary hydrogen in the aliphatic side chain and plating it with metal, preferably by electroless deposition. The aliphatic poly-α-olefin is preferably characterized by the general repeating unit wherein R 1 and R 2 are alkyl groups and x is 0 or 1, and has an open crystalline structure and a high melting point, with little difference, between the densities of the material in crystalline and amorphous forms. These properties are believed to be related to the strong adhesion obtained between such plastics materials and applied metal films. Poly-(3-methylbutene- 1), poly-(4-methylpentene-1) and poly-(4-methylhexene-l) are examples of suitable poly-α-olefins. Substrates of these materials may be oxidized in chromic acid, or in a mixture of chromic acid with a mineral acid, in either case with water. Alternatively flame treatment, corona discharge, glow discharge, ozonation or exposure to actinic radiation may be employed. The substrate is subsequently sensitized in a solution of stannous chloride or other reducing agent, then immersed in a solution of a salt of a noble metal such as platinum, palladium, silver or gold, a halide such as palladium chloride being preferred. Alternatively an initial metal film can be deposited by a spray-gun, by decomposition of metal carbonyls by cathode sputtering or by vacuum metallizing. The substrate so prepared is immersed in an electroless plating solution and copper, nickel or other metal deposited, then further metal, e.g. Cu, Ni or Cr is deposited by electroplating until the metal film reaches its final desired thickness. Metalplated polyolefins according to the invention are stated to be useful as knobs, handles, &c. and in applications including exposure to elevated temperatures, as in plumbing fixtures, printed circuits intended to be used at high temperatures, reflectors, &c.