TITLE

“MACHINE FOR TREATING COSMETIC POWDERS”

DESCRIPTION

The present invention relates to a machine for processing powders, more in particular cosmetic powders, optionally coated, and a process for producing these powders. In detail, the present invention concerns a machine that allows even finer milling (micronization) of a raw product already in powdery form as well as mixing powders of different kinds. The machine according to the invention also allows coating of said cosmetic powders, i.e., applying a liquid coating to the finely pulverized particles.

Equipment for milling, mixing and coating cosmetic powders and related processes for producing them are already known in the art.

In general, these equipment provide for initial milling carried out with micronizers or jet mills, while mixing and further reduction of the size of the powders is conducted with rotor mixers.

The powders are then generally coated with pigments in turbo-emulsifier devices, inside which said powders are maintained under pressure and agitated by means of air flows.

Current processes require numerous stages that involve various machines and equipment, meaning, above all, a costly and bulky system.

Moreover, the numerous stages involved in known processes mean that many hours of work are necessary to obtain the product suitable for the subsequent steps of preparation of the finished product, such as the pressing step, making it costly due to the labour costs required. In fact, prior art processes are carried out over a period of time of several hours, typically dozens of hours.

Moreover, these processes are also costly onerous in terms of the cost of stocks of semi-finished products; in fact, the process provides for, in a first step, the storage of the base/bases (according to formulation).

Moreover, added to said costs are the costs of quality control, which are high as this is continuous in each step, but also as it involves constant maintenance of the various machines to maintain the quality at suitable levels at all times, as a high quality standard is required in all operations carried out by the various machines.

In view of these considerations, there is the need to establish a faster and less costly process.

There has now surprisingly been found a machine by means of which to prepare consistent mixtures of cosmetic powders, such as a powder for a foundation, for a mascara, for a concealer, and to create the coated powders, which allows a reduction in the steps of the process to produce them and, consequently, a considerable reduction in the production times of these powders and also its costs.

With this machine it is possible to mix the powder components added thereto, to reduce the particle sizes of the powder to the required sizes and also to give these particles a suitable shape, i.e., tending as much as possible toward a lamellar shape that enables the powder to adhere better to the skin.

The machine according to the present invention is also advantageous as, in addition to the aforementioned operations, it is also capable of coating the particles of powder with suitable pigments.

An advantage of this machine is that it is able to carry out all the required processes, namely milling, mixing, coating, etc., without requiring to transfer the material from one machine to another during processing, with evident savings of time and costs.

The machine according to the present invention is of very limited size, and therefore occupies much less space relative to all the equipment used in prior art processes, including a micronizer, which alone is very bulky. This saving of space is an evident further advantage, in particular in terms of costs. Moreover, advantageously, this machine has a relatively limited production cost relative to all the equipment required until now to perform the same process, i.e., a few thousand euros instead of hundreds of thousands of euros.

Yet another advantage lies in the fact that with the machine according to the present invention it is possible to obtain powders having fundamental properties, such as size, shape and surface area, that are improved relative to those of the powders obtained with the prior art. These properties are essential for those technologies that define the powder cosmetically, i.e., slip, miscibility, hygroscopicity, compressibility, sedimentation speed and wettability, which in turn influence important parameters, such as the rheological properties of the suspensions and emulsions and the possibility of obtaining homogeneous mixtures and of maintaining this homogeneity through time. All the technological properties that define the powder then depend on these features.

A further advantage of this machine is that during the processing of components the temperature remains relatively low; this does not cause the problems that normally occur using conventional mills, i.e., clustering of the particles, hence increase of particle sizes and potential risk of alteration of the components used.

Therefore, the subject of the present invention is a machine for mixing and milling powders, in particular cosmetic powders, said machine comprising a body defined at least by side walls and a bottom wall and, preferably, a lid. Said body comprises at least two milling chambers communicating with one another; each chamber houses a rotor comprising at least one blade.

Each chamber is an environment for milling the powders, more in particular for micronization of these powders.

Hereinafter in the present description, the term“powder” or“powders” refers both to particles with sizes ranging from 0.5 to 1000 pm (micron) and to particles of smaller sizes, i.e., ranging from 0.1-0.5 to 10 pm; particles with these latter sizes are usually defined as micronized particles.

Moreover, for brevity the machine of the present invention is called milling machine, it being understood that it is also suitable for mixing and optionally also for carrying out other operations, such as coating the powder particles with suitable coatings.

Unless otherwise specified, the description below refers to a machine in the operating configuration, i.e. the common concepts of vertical, horizontal, etc., are specifically defined with reference to the acceleration of gravity.

Each milling chamber internally defines a milling volume.

Each milling chamber is preferably globally cylindrical in shape, with substantially vertical sides walls, while the bottom wall and the lid are substantially horizontal.

The two or more milling chambers are, preferably, identical in size, in particular with reference to the diameter.

However, according to a variant of embodiment, at least one milling chamber can have a different size from the at least one other milling chamber.

The milling chambers preferably extend in height. More precisely the diameter (D) and the height (H) of the chamber are in a D/H ratio ranging from 0.5 to 1.3 and more preferably from 0.6 to 1.2.

The rotor is, preferably, positioned centrally in said chamber. More precisely, this rotor is arranged so that its axis coincides with that of the milling chamber.

As mentioned previously, the machine can have a lid, preferably completely separable from the body. The lid also performs the function of hermetically closing the milling environment formed by the at least two chambers.

Preferably, said rotor is connected to the lid. More in detail, said rotor extends from the lid downward into the milling chamber.

The rotor comprises a shaft rotating along a substantially vertical axis and at least one blade supported by said shaft. If the milling chambers have identical sizes, preferably the rotors of the chambers are identical to one another in shape and size. According to an embodiment of the present invention, the shaft of the rotor does not come into contact with the bottom wall of the respective chamber, hence leaving a space between the free end of the rotor and said bottom wall. In any case, this distance is not large as also the powder placed on the bottom wall can be involved in the mixing and milling process of the machine according to the present invention.

As mentioned above, the shaft of each rotor supports at least one blade. The blade has the following features, taken individually or in any combination thereof:

- a slightly arched shape;

- a thickness that varies, preferably, from 1 to 6 mm, more preferably from 1 to 5 mm, even more preferably from 2 to 4 mm;

- a plan width that decreases from the base, at the shaft, toward the end; and

- preferably, a length so that the length (L) of the blade relative to the diameter (D) of the chamber varies, according to a L/D ratio, ranging from 0.25 to 0.49, more preferably from 0.3 to 0.35.

The aforesaid length L of the blade is understood as the distance of the point farthest from the axis of the rotor, substantially equal to the radius of the circumference described by the blade during rotation.

The blade has edges at least one or both of which can either be sharp or unsharpened.

Preferably, each shaft has two, three or more, more preferably four or more, blades.

In the present invention, the shaft has a blade or at least one blade positioned at a level relative to the bottom wall so that at least one blade is immersed in the powder to be processed during operation of the machine.

More in particular, said at least one blade, positioned inside the chamber, is, typically, at a height (h) not too far from the bottom wall, i.e., at a height such that the vortex caused by the rotational movement of the blade is also capable of involving the powder placed on the bottom wall.

Preferably, the h/H ratio between said distance (h) of the lower blade from the bottom and the height (H) of the chamber ranges from 0.02 to 0.25.

Likewise, said blade or at least one blade has a length such that the particles of powder close to or in contact with the side walls of the body are also involved in the rotational movement created by the blade so that they too are subjected to the processing operations performed by the machine according to the present invention.

When a shaft has two or more blades, the blades can have features of thickness, length, etc., different from or the same as one another.

Moreover, the blades can be arranged in various ways along the shaft. For example, all the blades are substantially coplanar or arranged at different levels along the shaft. At each level there can be a single blade or an assembly of two or more blades. The blades at the same level are, preferably, coplanar.

In other words, in this way the blades are arranged so as to form a series of blades along the shaft, arranged singularly or, preferably, in groups.

Preferably, the levels are spaced regularly from one another.

The levels are two or more, according to the size of the chamber.

Each assembly of blades has at least two or more blades. The blades in each assembly have lengths different from or, more preferably, identical to one another.

The assembly of blades is formed by blades, preferably angularly spaced at equal distances from one another.

Two assemblies of adjacent blades on a same shaft are, preferably, at a distance (1) such that the 1/H ratio, where (H) is the total height of the chamber, preferably ranges from 0.02 to 0.40. Two blades or two assemblies of blades positioned at adjacent levels on a same shaft can be aligned with one another along the vertical, or not. In the latter case, the blades or the assemblies of blades are, more preferably, angularly staggered from one another. If there are two pairs of blades, these pairs are, preferably, orthogonal to each other.

Adjacent rotors have blades or assemblies of blades all at different heights along the respective shafts. In other terms, two adjacent rotors are different from each other at least for the distance of positioning of each blade or of each assembly of blades relative to the bottom wall of the chamber.

Preferably, this positioning of the blades or of the assemblies of blades in adjacent rotors is such that the blades or the assembly /assemblies of blades of a first rotor is/are positioned staggered relative to the blades or to the assembly /assemblies of blades of the adjacent rotor.

In this way the blades of adjacent rotors can be superimposed during rotation, in the area of communication between the two chambers, without impacting one another.

Besides said staggering of the levels of the blades, two adjacent rotors can be different from or the same as each other with regard to length of the shaft, number of assembly of blades, orientation of the blades, features of the blades, i.e., number of blades, their thickness, length, etc.

According to the embodiment of the present invention, the rotors have the same direction of rotation.

According to the present invention, two adjacent cylindrical milling chambers have a distance between centres of less than the sum of the radii of said two chambers. Preferably, said distance between centres (I) has a value such that the I/D ratio, where (D) is the diameter of the chamber, ranges from 0.35 to 0.85, more preferably from 0.5 to Therefore, according to the present invention, two adjacent milling chambers have a configuration such that the cylinders are not complete but are partially superimposed on one another. Therefore, two adjacent milling chambers of the machine according to the present invention substantially have the shape of an 8.

Consequently, where the milling chambers join, the milling chambers define therebetween an area of intersection by means of which the two adjacent chambers are in fluid communication, so that in this area of intersection the flows of powders coming from the two adjacent milling chambers intersect and move from one chamber (first chamber) to the adjacent chamber (second chamber), as in this area there is no fixed obstacle that opposes the passage of material from one chamber to the other. The intersection of the two flows of powders not only allows a flow to pass through the flow it intersects, but also entails a collision between particles also of the two flows that intersect. This collision occurs between particles that move at high speed and, therefore, contributes to cause the particles to take the desired final size and shape. In fact, the collisions cause events such as crushing and rounding of the particles, contributing, in addition to the action of the blades, in helping to obtain powders with particles of the desired size and shape.

Said area of intersection is delimited by two cusps. This area of intersection has a width that depends on the diameter of the adjacent chambers.

According to a particular embodiment of the invention, the two chambers have identical diameters (D) and are arranged with their axes spaced apart by a distance between centres (I) such that the I/D ratio is of around 0.65.

According to said embodiment, the rotors are identical to each other in shape and size; each shaft comprises two assemblies of blades, directly connected to the shaft, where each assembly of blades consists of two pairs of blades. The blades of each pair are coplanar and are opposite each other relative to the axis of the rotor. Moreover, preferably, the first pair of lower blades and the second pair of upper blades are arranged orthogonally to each other in a plane orthogonal to the axis of rotation of the rotor.

Each blade of a pair of blades has an arched shape with an edge sharpened in proximity of the convex side of the blade.

The arrangement of the blades toward the end of the shafts, hence closer to the bottom of the chambers, allows triggering of internal flows of the powder which enable complete remixing of the powder and prevent stagnant areas.

According to the invention, said rotors are rotated by a motor. Each rotor can be rotated by a corresponding motor thereof.

Alternatively, two or more rotors are rotated by only one motor. These rotors are, optionally, connected to said motor by means of appropriate transmission means.

The at least one motor can be housed on the lid, in particular on its upper surface, or a part thereof.

Alternatively, the machine has no lid and comprises a supporting element placed above the milling chambers, which supports the rotors and optionally the at least one motor and from which said rotors extend downward inside the milling chambers.

According to the invention, the motor, or the motors, is/are configured to rotate the rotors at a speed of at least 1000 rpm, preferably at least 1200 rpm, typically from 1300 to 3000 rpm, in some variants even up to 8000 rpm.

This rotation speed, in combination with the geometry and the arrangement of the blades and with the shape and the arrangement of the mixing chambers described above, triggers phenomena of impact of the particles with the blades and of particles against one another that enables said particles both to reduce their size considerably, to a level of micronization, and to take the desired final shape.

The ideal range of rotation speeds is also a function of the capacity of the machine, i.e. of its dimensions, in particular of the diameter of the milling chambers and, hence, of the length of the blades. In general, machines with blades having a limited maximum operating diameter (DL) require a higher number of revolutions to operated correctly and ensure the above-mentioned effects.

According to an embodiment, the machine also comprises a cooling system that prevents the temperature inside the machine according to the present invention from becoming too high. In fact, it is preferable for the temperature inside the mixing chambers not to exceed 90° C and preferably 80° C. This system includes cooling means located, for example, along the side walls of the body of the machine, to allow a cooling fluid to circulate. These means can be configured as a serpentine or, more preferably, a sleeve or a gap attached at the level of the walls of the body of the machine.

According to a preferred embodiment, the lid is mounted on supporting means provided with actuator means that allow the lid, optionally supporting at least one motor, or the rotors, or both, to be opened and closed easily.

According to a further embodiment, the shaft also supports mixing means, for example with a laminar or cylindrical shape, to allow, where necessary, an action essentially of mixing the powders present in the chambers.

According to an embodiment of the invention, the machine is equipped with one or more distribution devices of a liquid adapted to generate an atomized jet of a liquid inside the mixing chambers. Said distribution device can be used to wet the powders with a liquid, typically a pigment, to perform the coating operation of the particles.

Said distribution device preferably comprises at least one nozzle mounted on the wall of the milling chamber or, more preferably, on the lid. Preferably, the machine comprises at least two nozzles, each placed above a respective milling chamber. Said nozzles can be fed by a pumping device, which can be mounted on the lid or, in any case, included in the machine, or by an external device. The subject of the present invention also relates to a process for preparing cosmetic powders based on suitable powdery raw materials.

This process provides for the use of the machine according to the present invention, which allows milling and optionally mixing actions of the powders to be conducted until obtaining particles of very small size (micronized particles) and also coating actions with suitable coating agents to obtain a semi-finished product or even a finished product.

The coating agents can be chosen from agents (such as titanium oxides) that provide the particles with particular properties, such as hydrophobia, oil dispersion properties or an increase in their feeling to the touch.

Said process comprises a stage of filling the mixing chambers with at least one powder product, where said powder product comprises at least one substance that can be used to produce a cosmetic product.

This process further comprises at least one of the following stages:

a milling, or also mixing, stage of powders, conducted at a rotor speed ranging from 1000 to 8000 rpm for a time ranging from 2 minutes to 10 minutes, and at a temperature ranging from 25 to 90° C; and/or

a coating stage, wherein a coating agent is added to the powders, preferably milled and/or mixed, for example obtained in the preceding stage; this stage is conducted at a rotor speed ranging from 1800 to 8000 rpm, for a time ranging from 5 to 30 minutes and at a temperature ranging from 25 to 90° C.

This process, carried out with the machine of the present invention, can comprise only a milling stage, optionally combined with a mixing step, or only a coating stage, or the first followed by the second.

According to an aspect of the invention, the process for carrying out only milling (micronizing) of a homogeneous powder or of pre-mixed powders, provides for operation of the rotors at a speed ranging from 1000 rpm to 4000 rpm for a time ranging from 5 to 10 minutes.

The aforesaid parameters can also be maintained in the case in which the milling stage also comprises the mixing of different powders, where said powders are placed in the milling chambers simultaneously before the machine is switched on.

During the coating step the machine can be operated constantly or, if necessary, said step can be carried out in several sub-steps spaced apart by pauses of a few minutes (from 1 to 5 minutes) to allow the material to rest and cool.

Depending on the type of operations carried out, as mentioned above, the product obtained from the process of the present invention can be a semi-finished or a finished product.

Said process can further comprise a stage prior to said milling and mixing stage, in which the powders are usually mixed through the action of the above-mentioned rotating means. In this stage the rotors rotate at a speed generally ranging from 300 to less than 1000 rpm.

It can be noted that after the product has been unloaded from the machine according to the present invention, the product is ready to directly undergo the compaction step, i.e., it is no longer necessary for the product to undergo an intermediate sieving step before the compaction step.

With the machine of the present invention, the total process time inclusive of the mixing and crushing steps and of the subsequent coating step is of around 30 minutes, compared to the almost 24 hours required with machines and processes according to the prior art.

In fact, as already mentioned, the processing steps with the machine of the invention are carried out in sequence without having to move the material from the milling chambers.

Other features and advantages of the invention will be apparent from the following detailed description of non-limiting embodiments of the invention, with reference to the accompanying figures, wherein:

- Fig. 1 represents a perspective view of a machine according to the present invention, in a configuration at rest;

- Fig. 2 represents a side view of the machine of Fig. 1;

- Fig. 3 represents a top view of the machine of Fig. 1;

- Fig. 4 shows a sectional side view of the machine of the present invention, in operating configuration;

- Fig. 5a represents a plan view of the milling chambers of the machine of Fig. l;

- Fig. 5b is a plan view of the rotors and of the blades;

- Fig. 6 represents a diagram of a process carried out with the machine according to the present invention;

- Figs. 7a - 71, 8a - 8n show electron microscope images of samples of powders analysed after some comparative tests conducted with the machine of the present invention;

- Fig. 9 is a graph deriving from analyses conducted on samples of materials processed with the machine of the present invention.

With reference to Figs. 1 and 2, an open milling machine according to the present invention is indicated as a whole with 10.

In the example provided, the sizes indicated relate to a machine with a capacity (amount of proces sable material) up to 80 kg.

It is understood that the machine according to the invention can be produced with different sizes/capacities, lower or higher, and its characteristic dimensions are identified according to the size ratios cited above.

Said machine 10 comprises a body 1 delimited by side walls 2, a bottom wall 3 and, opposite this, a lid 13; these elements define a single environment inside which two milling chambers 11, 12, each globally cylindrical in shape, are positioned. The two chambers are identical in size.

Each chamber has a diameter D of 550 mm, while the distance between centres I of the two chambers 11, 12 is of 350 mm. The distance between centres (I) and the diameter (D) are in a ratio of 0.65. The height (H) of the chambers is instead of around 800 mm.

As illustrated in Fig. 4, said two chambers 11, 12 are in communication with each other in an area of intersection 20 delimited by two cusps 26, 27.

Each chamber 11, 12 is provided with a rotor 4, 5, which rotates along a substantially vertical axis at the rotation axis of each chamber 11, 12.

According to the embodiment illustrated, the lid 13 is completely separable and completely closes the two chambers 11, 12.

The lid 13 supports, on the upper side, two motors 23, 24 and, on the lower side, the two rotors 4, 5.

In the two chambers 11, 12, the rotors are identical to each other in shape and size.

Each rotor 4, 5 is formed of a shaft 21, 22 and two assemblies of blades connected directly to the shaft. Each assembly of blades consists of two pairs of blades 21a, 21b, 22a, 22b.

The shafts 21, 22 do not come into contact with the bottom wall 3. The bottom wall of the chamber and the free end of the shafts 21, 22 are at a distance that generally varies from 5 mm to 30 mm.

The blades of each pair are coplanar and are opposite each other.

With reference to the first rotor 4, the first pair of blades 21a is arranged at the level or in proximity of the free or lower end of the shaft 21. The second pair of blades 21b is arranged above the first pair of blades 21a at a distance of 55 mm.

Moreover, the first pair of blades 21a and the second pair of blades 21b are arranged orthogonally to each other in a plane orthogonal to the rotation axis of the rotor.

With reference to the second rotor 5, the first pair of blades 22a is arranged at a distance of 45 mm from the free end of the shaft 22. The second pair of blades 22b is arranged above the first pair of blades 22a at a distance of 55 mm.

Moreover, also the first pair of blades 22a and the second pair of blades 22b are arranged orthogonally to each other in a plane orthogonal to the rotation axis of the rotor.

Therefore, these pairs of blades of a shaft are staggered in height relative to the pairs of blades of the adjacent shaft. Consequently, the shaft 21 has pairs of blades 21a, 21b positioned at a level that is different from the level of the pairs of blades 22a, 22b of the shaft 22.

Moreover, the orientation of the blades of the first pair of blades 21a is identical to that of the first pair of blades 22a. Likewise, the orientation of the blades of the second pair of blades 21b is identical to that of the second pair of blades 22b.

The lid 13 is mounted on supporting means 14 and is moved by hydraulic or pneumatic actuators 16 that enable the lid to be moved according to needs.

According to a preferred variant illustrated in Fig. 4, the machine comprises a pair of nozzles 25 mounted on the lid 14 and configured to direct an atomized jet of a liquid downward, i.e., into the milling chambers. Said nozzles 25 are preferably fed by a pumping device, not visible in the figures. Optionally, the number of nozzles can vary according to requirements, for example there can even be two, three or more for each milling chamber.

The machine of the present invention is capable of carrying out various operations on the powders inserted therein, in particular milling, more in particular micronizing, mixing and, optionally, also coating, without it being necessary to move them to distinct specific machines for said operations.

More precisely, the machine according to the present invention enables a process (illustrated in Fig. 5) to be carried out to prepare, for example, a foundation powder in a single stage introducing the necessary powders, not yet micronized, into the mixing chambers, to obtain the desired mixture. For example, after being weighed, the base powders (such as talc, com starch), the pigments, the binder system, the preservative agents, any other raw materials (such as antioxidant molecules) are introduced into the chambers.

The semi-finished product obtained can be subsequently processed in the same machine with suitable coating agents that are introduced later, i.e., after the mixing and crushing stage. At the end of this process, a homogeneous finished product ready for the compaction step is unloaded.

With a process conducted with the machine according to the present invention, as illustrated previously, a mixture of various powders and also coated powders with good features can be obtained; in particular the mixture of powders has greater homogeneity relative to a mixture of the same type of powders obtained by means of a process that uses prior art equipment; consequently, the former also has very good slip, i.e., it is easier to spread on a surface relative to the latter. The texture of the first mixture of powders is also better compared to the second; this is also important in the case of powders for use in the cosmetic sector. Moreover, the first mixture has a better final stability relative to that of the second mixture. Ultimately, with the machine according to the present invention the product obtained has a better overall quality relative to that of the product obtained with a process that uses prior art equipment.

Moreover, the greater homogeneity of the size of the particles of the mixture means that the sieving stage of the powder before its compaction step is superfluous, making the process of the present invention faster and simpler relative to those of the prior art.

To assess the effects obtained with the machine and with the process of the present invention, the applicant conducted some comparative tests with a machine of the prior art.

The machine used for comparison is a mixer/mill model MC4 manufactured by VE.TRA.CO GROUP, (hereinafter conventional mill) commonly used for the preparation of cosmetic powders, in particular to conduct the mixing and coating steps.

The machine according to the invention used had a capacity of 5 kg and was equipped with milling chambers having a diameter (D) of 200 mm and a height (H) of 210 mm.

More in detail, to assess the effect of the two machines, conventional and of the invention, on the powders during the milling (micronization) step.

For all the samples processed a micro structural characterization was carried out using a high resolution Scanning Electron Microscope (SEM, TESCAN Mira 3 XMU) operating at 8 kV. Microanalysis was performed using X-ray emission spectrometry (Energy Dispersive Spectrometry EDS, ED AX), operating at 20 kV. The samples were previously coated with platinum (for microstructural characterization) or with carbon (for microanalysis) respectively using the Cressington HR208 or Cressington 208c instrument.

TEST No.l

In this test comparison was carried out between the talc M5, commercially available and not processed, relative to the same processed in the machine of the present invention and in the conventional mill. The commercial raw material Talc M5 has a mean diameter as indicated in the respective technical data sheets, more precisely of around 26 pm.

The samples analysed are indicated in the table below in which the operating parameters used for the two machines are provided. Table 1

Figs. 7a to 71 show some images of the samples detected under the microscope. The images are carried out at different levels of magnification indicated in the image itself. For each imagine the related sample analysed is indicated.

As can be noted from the images, the sample T5 NM is the one that, in a global vision, has a larger component of particles of smaller sizes. For example, at greater magnifications (2.00Kx, 5.00Kx), Figs. 7 b-c, and-f, h-1 where the shape parameters and sizes of the three samples can be appreciated, it is noted that the sample T5 has the particles with the largest sizes. The samples T5 VM and T5 NM both have particles of smaller sizes relative to the unprocessed sample T5 but it can be noted that the sample T5NM has a larger component of particles of very small sizes. TEST No.2

A further test was conducted processing powders of finished products. More in detail, the test was conducted on two different samples of “baked eyeshadow”. The samples analysed are indicated in the table below in which the operating parameters used for the two machines are provided. Table 2

Figs. 8a to 8n show some images of the samples detected under the microscope. The images are taken at different levels of magnification indicated in the image itself. For each image the related sample analysed is indicated.

As can be noted from the attached images, in the samples L569 NM and L579 NM processed with the machine of the invention the particles have a finer/thinner lamellar structure relative to the samples L569 VM and L579 VM processed with the conventional mill.

This feature of the particles allows improved adhesion to the skin, as well as giving the powder a superior feeling to the touch.

TEST No.3

The applicant conducted another non-comparative test only using the machine of the invention to verify the efficacy in the coating process of an oxide with different agents. The oxide processed is a“yellow iron oxide” pigment. The table below indicates the various samples analysed corresponding to unprocessed oxide, only milled with the machine of the invention and milled and coated with various elements. Table 3

The unprocessed and processed samples underwent microanalysis to highlight their changes at chemical level following only milling or milling and coating process. Table 4 below indicates the results obtained by the microanalysis carried out on all the samples. The results are expressed as percentage of presence of the element relative to the total found.

Table 4

The attached Fig. 9 instead shows a graph indicating whether processing with coating agents led to modifications of the sample. In the graph for each sample, the variation of the elements of greater interest (C, O, Si, Fe) is expressed as ratio relative to the content in the sample as is. Therefore, the more the ratio is close to or the same as the value 1 the more the samples are similar. From the attached graph it can be seen that only the milling process with the machine of the invention does not cause variations of the main elements, namely Iron, Oxygen and Silicon. The graph also shows that the coating process with Silane and Dimethicone, which both contain Silicon, leads to an increase in the content of this element respectively of 17 and of 22%, showing that coating has taken place.

Processing with Chitosan leads to an increase of over 200% of the presence of Carbon; this result also allows us to conclude that coating took place in a satisfactory manner.