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The present invention relates to a process for coloring solid compact powder cosmetic products. A method is known from FR 2759941 A1 for carrying out the surface decoration of a compact solid powder cosmetic product, in which an inkjet printer carrying out ink jets of various cosmetically acceptable pigments or colors is used. The limit of this technology is the size of the pigments used, which must not be greater than 1 micron in order to prevent clogging up the printer.

In order to overcome this limit of the prior art, the present invention provides an innovative technological process, which consists in coloring compact solid powder cosmetic cakes by impregnating them with inks of various colors dripped in the form of droplets from adjustable nozzles onto the upper surface of the cake for then being impregnated therein in order to create special effects with color effects and shades.

The treatment has the function of embellishing the product. In fact, many chromatic effects with great esthetic and functional effect are obtainable, as the product is not only colored on the surface but also throughout the mass thereof. Therefore, it is possible to start from powdered cosmetic cakes of only one starting color, for example white, and then color them with any design, color, or shade of color. The decoration does not remain on the surface, but is a real coloring throughout the mass, i.e. the ink penetrates deeply into the powder cake. It is also possible to use pigments of any size without problems of clogging up the dripping devices.

Figures 1 and 2 show a top plan view and a diametrical sectional view according to line II-II in figure 1 of a cosmetic cake 1, by way of example of a circular shape, which has a lower surface 2 intended to rest on any support and a variously shaped upper surface 3 intended for the visual appreciation by the consumer. During the coloring process, the cosmetic cake 1 rests on a support and is then wet by dripping a certain number of droplets of one or more colored inks, until the material of which the cake is made is impregnated by capillary action and in depth, taking on different colors and shades. The dosing of the inks is carried out by using adjustable dropping nozzles, diagrammatically drawn and indicated by reference numeral 4 in figures 3 and 4, actuated by a control system (not shown as conventional per se) which allows a defined number of color droplets 5 to be dropped into various zones of the upper surface 3 of the cosmetic cake 1 following programmable and repeatable trajectories. Zones 6 impregnated with various colors are thus created, which esthetically characterize the cosmetic cake.

The ink amount of which each droplet is comprised, as well as the dispensing speed thereof are adjustable by means of 3 parameters:

• Nozzle opening time · Pressure inside the ink tank

• Nozzle opening section

During the process, the nozzles and/or the cosmetic product cake to be colored can be moved on four axes (x,y,z,£l) by means of servo-controlled actuators, according to a path which is totally programmable in G code language (that used on CNC machine tools) and reproducible. It is thus possible to create, for example, spotted or shaded effects by superposing different colors (figures 5-7, where numbers 7-16 and the marks used represent possible zones with different coloring and/or different shading), but also the impregnation of different colors of portions 17-20 of the same cake clearly divided from one another (figures 8-9).

The aforesaid step of coloring the upper surface of the cosmetic cake by dripping, penetration, and impregnation of the various colors into the cake itself is followed by a step of drying the cake, which is obtained through a heat treatment carried out at a temperature between 20°C and 90°C, preferably between 35°C and 80°C. This heat treatment can be carried out by any suitable heating method, such as insertion into a ventilated oven with controlled humidity, with air recirculation, a microwave oven, or the like, for example.

The various types of powdered cosmetic products to which the coloring process according to the present invention can be applied include the following:

• Cosmetic powder obtained by a pressing process

• Cosmetic powder obtained by an extrusion process

• Cosmetic powder obtained by a backing process

• Cosmetic powder obtained by a pouring process

Examples of compositions of powdered cosmetic products with which the process according to the present invention can be used are indicated herein. Cosmetic powder obtained by a pressing process Cosmetic powder obtained by an extrusion process Cosmetic powder obtained by a backing process Cosmetic powder obtained by a pouring process EXAMPLES OF INKS Table 1

* Non-limiting examples of water soluble natural dves/extracts:

Beetroot red

Cl 40800 / Beta-Carotene

Cl 75810 / Chlorophyllin-copper complex

Caramel

Cl 75470 / Carmine Spirulina Platensis Extract*

Ipomoea Batatas Root Extract Turmeric Longa (Turmeric)Root Extract Raphanus sativus, extract

Table 2

**Non-limiting examples of water soluble synthetic dyes:

CI10316 / Ext. Yellow 7 CI45350 / Yellow 8 CI15985 / Yellow 6 CI19140 / Yellow 5 CI60730 / Ext. Violet 2 Cl 17200 / Red 33 045410 / Red 28 045380 / Red 22 014700 / Red 4 059040 / Green 8 061570 / Green 5 042053 / Green 3 042090 / Blue 1

Cl 14700 / 0 19140 / 0 17200 /D&C Brown n.l Table 3

*Non-limiting examples of solvents:

Volatile linear silicones (Dimethicone, Hexamethyldisiloxane ...)

Cyclic volatile silicones (Cyclomethicone, Cyclohexasiloxane, Octamethyltrisiloxane....)

Volatile hydrocarbons (Isododecane, Isohexadecane, 1.2 Hexanediol....) Alcohols (Ethanol, Isopropyl alcohol....)

Glycols (1.2 Hexanediol...)

**Non-limiting examples of fat soluble dyes: Cl 47000 / Yellow 11

Cl 60725 / Violet 2 Cl 61565 / Green 6 Cl 26100/ Red 17