Background art This method, which combines the advantages of anodization with the advantages of coloring, decoration and painting, allows to act directly with the finishing coat, i. e., to avoid the primer coat, although it is in any case possible to achieve, during sublimation of the decorations and painting, higher bonding coefficients than observable with any other conventional method. It is in fact well-known how difficult it is to obtain appreciable results in the painting of items made of aluminum and its alloys, due to the fact that the morphological characteristics of the anodized surface of said items, in relation to the structural configuration of the affected region, do not allow spontaneous penetration and therefore adequate bonding of any paint or decoration, since the surface pores are blocked or in any case so small and unstable as to prevent penetration of the resinous pigments of the decorations and of the protective paints.

I Disclosure of the Invention The aim of the present invention, instead, is to achieve particularly high adhesion values with plant and production costs advantageously modest, in which the paint can be applied with a normal electrostatic method.

It should be observed that normal galvanic treatments (anodization) give the surface layer of items made of aluminum and alloys thereof a microstructure which is different from, and has a lower porosity than, the original microstructure, since during the final step of this treatment the

pores of the anodized layer tend to close due to hydration and swelling of the oxide.

This surface configuration, which gives high protection to the metal, makes it substantially impossible to bond any paint or decoration applied subsequently.

Generally speaking, the present method also provides for the galvanic treatment of anodization of the aluminum with sulfuric acid, but in the specific case this occurs with appropriate conditions of the ratio between time and voltage and with the exclusion of the fixing step from the galvanic cycle.

Before moving on to the description of the new process according to the exact chronological order of its various steps, it should be observed that the values of time, voltage and temperature parameters are exclusively given by way of non-limitative examples, since the object of the invention being to uniformly coat the items with a suitable layer of oxide, such parameters may be varied according to the mass and structure of the metal.

Ways of carrying out the invention According to the invention, a method for the anodic treatment, inorganic coloring and/or electrocoloring, decoration and electrostatic painting of items made of aluminum and alloys thereof, comprises in a preferred embodiment, the steps of: 1-Anodic treatment, for a time between 8 and 45 minutes, at a temperature of 19 to 24°C and at a voltage of 10 to 22 V.

2-Inorganic coloring by absorption and/or electrocoloring or coloring by means of an electrolytic process.

3-Rinsing and washing in demineralized or distilled cold water, which is accordingly free from scale residues.

4-Drying in air at a temperature below 35°C.

5-Wrapping the items, first with paper on the inside of which the decorations to be transferred are provided, then with a layer of soft or

spongy material and finally with an enclosure made of thermoplastic and elastic material which, by withstanding a temperature of at least 220°C without losing elasticity, compresses the soft or spongy material and ensures uniform adhesion of the decorated paper to the shape of the item while a suitable vacuum pump produces vacuum inside said enclosure and keeps the assembly in these conditions inside an oven, where it remains for 1 to 8 minutes at a temperature of 200-220°C.

6-Painting, to directly form the finishing coat, and without a primer, with clear or pigmented organic paints which are in any case suitable for subsequent baking, whether in liquid form or in powder form, polyester-or polyurethane-based, appropriately pigmented and preferably with UV adsorber for protection against ultraviolet radiation.

7-Baking at approximately 180°, during which the paints polymerize and the oxide is fixed, the colorings and the decorations remaining set in the pores of said oxide.

It should be specified that the stages described in step 5 including sublimation or transfer, without altering the preceding and subsequent steps, can be simplified by using decorated polyester sheets, which are already commercially available. It is possible, in this respect, to use said sheets to form enclosures which, after being bonded by ultrasonic methods or other methods, and enclosing the individual items, are connected to the vacuum pump in order to produce vacuum and ensure the adhesion of said enclosures, with the decorations, to the shape of the items, during the stay time in the oven for the already specified time and temperature.

Apart from the efficient technological simplicity of the entire process, attention is drawn to: --the lower cost of the anodic treatment, since it no longer includes the fixing step; --the lower cost of painting, since there is no priming treatment; --the high level of finish and the wide range of aesthetic effects that can

be easily reproduced, from the grain of wood to any other pattern, by the combined action of the oxide and of the substances set therein during coloring, decoration and painting; --the possibility to use the new method by adapting existing systems with limited technical commitment and with a low financial investment.