Imperial Chemical Industries Limited

Andrew Doroszkowski

Peter F Nicks

Maurice W Skinner

Peter Butler

Michael A Toynton

Alan R Barlow

A process for coating an article simultaneously with a metal and a film-forming polymer which comprises passing an electric current at a current density of 1 to 35 milliamps cm.sup.-2 between the article as a cathode and a counter-electrode immersed in an aqueous coating composition having an inherent pH of 2.5 to 9.5, comprising:

Coating process and composition

A process of coating a surface of an article which is capable of being heated, by contacting the heated surface of the article with a coating composition comprising an aqueous dispersion of an organic film-forming material which is sterically stabilized and which has a critical coalescence temperature which is lower than the temperature to which the surface of the article is heated. Suitable coating compositions are described.

Process of coating a heated surface

A coating process in which an article to be coated is immersed as an anode in a dispersion of a film-forming material stabilized by non-ionic stabilization and an electric current is passed between the anode and another electrode immersed in the dispersion. The dispersion is destabilized in the region of and is deposited on the anode by interaction between a moiety providing the non-ionic stabilization (e.g. of polyethylene glycol) and a further interactive moiety (e.g. carboxyl groups present in polymethacrylic acid) present in the dispersion. Suitable coating compositions and coated articles are defined.

Electrophoretic coating process

A process of coating with film-forming material an article which is made a cathode in an electrical circuit and is immersed in either an aqueous dispersion of a derivative of the film-forming material comprising a stabilizing cationic group hydrolyzable at the cathode or an aqueous dispersion of the film-forming material stabilized by association with a distinct surfactant comprising a cationic group hydrolyzable at the cathode, to yield the film-forming material as a coating on the cathode when electric current is passed between the cathode and a counter-electrode. Also suitable coating compositions in which the film-forming material is primarily stabilized by ionic groups hydrolyzable at the cathode.

A conductive substrate as cathode is coated by electrodeposition using a coating material which comprises a sterically stabilized dispersion of film-forming polymer particles in an aqueous medium, the polymer comprising or being associated with a stabilizing polymeric non-ionic hydrophilic moiety which is solvated by the aqueous medium and being free from stabilizing ionic charges. The dispersion of film-forming polymer particles has a critical coalescence value which is more negative than -0.3 units.

Coating process

A method of producing a paint composition. The composition comprises a pigmented solution of a water-insoluble film-forming base resin in a water-immiscible liquid, the solution of the base resin being emulsifiable in an aqueous synthetic detergent solution. The method of making the paint composition includes the step of treating at least a portion of the pigment in dispersion in water-immiscible liquid with an auxiliary resin which (a) is co-emulsifiable in the aqueous detergent solution with the pigment when dissolved in the water-immiscible liquid of the paint composition and (b) is preferentially adsorbed by the pigment from a solution of both the base resin and the auxiliary resin in the water-immiscible liquid of the paint composition. The pigment of the paint composition comprises a pigment having an acidic surface. The final paint composition is satisfactorily emulsifiable in a 5% by weight solution of a synthetic detergent.

Growing community of inventors

Marlow, United Kingdom

Andrew Doroszkowski