FR1254217A - Product for degreasing and phosphating ferrous surfaces - Google Patents

Description

i Product for degreasing and phosphating ferrous surfaces. Before subjecting a metal surface to assembly work by welding or otherwise, or to a finishing work such as painting, it is necessary to prepare it by subjecting it to a treatment to remove rust, calamine or other, or even degreasing and phosphating.

At least one product is already known for removing rust or scale covering ferrous surfaces in a single operation, this treatment also ensuring at the same time the passivation of the surface treated by the intervention of phosphate salts. acids in the nascent state; but this treatment does not allow degreasing and phosphating with a view to a subsequent application of paint, the good adhesion of which must be ensured. This is only achieved by using methods in which several different products are successively employed for this treatment.

The degreasing and phosphating process, object of the invention, makes it possible to treat, during a single operation, the ferrous surfaces which need it to make them suitable for receiving and keeping well attached the paints which they are subsequently. covered. For this purpose, use is made of a mixture in aqueous solution of at least one weak acid releasing hydrogen ions, of at least one oxidizing metal salt limiting their action and of at least one surfactant product, the mixture of which is reduced. the reducing effect and the reaction on iron to the formation of stable insoluble salts by incorporating therein alkyiphenoipolyoxyethylen as well as sodium alkoxide and a salt derived from ethylenediamidotetraacetic.

The presence of these last three bodies increases the degreasing power of this mixture in considerable proportions.

By way of non-limiting example, there is given below a composition, giving good results, of a product having remarkable qualities for phosphating and degreasing metal surfaces in a single operation Orthophosphoric acid, 100 to 150 g; Zinc or manganese oxide, 3 g; Magnesium or potassium carbonate, 3 g; Trisodium phosphate, 10 g; Aikyiphenolpolyoxyethylene, 15 g; Salt derived from ethylenediamidotetraacetic acid, 2 g; Sodium hydroxide, 2 g; Water, 805 g.

If the products are pure, the product obtained at the end of the mixing is a perfectly clear and colorless solution which does not deteriorate and retains its properties until exhaustion.

When cold, this solution can be used pure or slightly diluted with water, either with a brush, a cloth or a sponge, or in a bath with a slight turbulence to activate the degreasing. But it is indicated that the result is faster and the phosphating better by using the product at a temperature close to 50 to 80 C, either with a jet or in a bath, adding ten times its volume of water, which also makes it more economical.

As goes without saying, the invention is not limited to the only mixture, the composition of which has been indicated above; it also embraces all the variants thereof, both in relative percentage of the products and in the choice which has been determined, in particular concerning the weak acid (s) used, the oxidizing agent (s), and the surfactant compound (s) contained in the mixture described .

Claims (1)

SUMMARY 1 As a new industrial product, a product for degreasing and phosphating ferrous surfaces, consisting of a mixture in aqueous solution of at least one weak acid releasing hydrogen ions and of at least one oxidizing metal salt by limiting the action and at least one surfactant product with the addition of zinc or manganese oxide, characterized in that, to reduce the reducing effect of this mixture, at least one ethylene product is added thereto. 2 Product as specified in 1, consisting of a mixture in aqueous solution and suitable proportions of orthophosphoric acid, 100 to 150 g; Zinc or manganese oxide, 3 g; Magnesium or potassium carbonate, 3 g; Trisodium phosphate, 10 g; Aikylphenoipoloxyethyiene, 15 g; Salt derived from E.D.T.A. (ethylenediamidotetraacetic, 2 g; sodium aikylate, 2 g; Water, 805 g.