COSMETIC PRODUCT STERILIZATION
This invention relates to a method for sterilizing a cosmetic product, in which said product consists of a fluid circulating under pressure in a sterilization circuit, which consists in successively pre-heating said product ; heating said product for a short period at high temperature ; immediately cooling said product; and conditioning the product in a sterile atmosphere.
This invention falls within the field of cosmetology, in particular within the manufacture of cosmetic products.
The invention relates in particular to a method for sterilizing cosmetic products, and the device for implementing same.
In order to improve the preservation of a cosmetic product, preservatives enter into its composition, which are namely aimed at preserving the properties of said product while protecting it against contaminants. The preservatives are listed in a listing identified by approved bodies. A group of preservatives used are parabens, which impede fungi and bacteria growth. These components have however the drawback of being toxic for the body and are hazardous for the users' health.
The manufacturers thus tend to replace the parabens by other components that can act as preservatives. The products used are however not always present in the 30 approved lists and are not fully satisfactory.
One has therefore thought of sterilizing the cosmetic products instead of incorporating preservatives. Several methods and devices of the state of art, described for example in JP 60025907 and JP 10025235, consist in sterilizing the cosmetic product by heating in a temperature range varying between SO and 80 degrees Centigrade. However, the devices used are not fully satisfactory over the life time of the product and their implementation is complex.
One has thus thought of sterilizing at very high temperature, in the range from 135° to 150 , still through circulating a fluid through a circuit passing through heating and cooling baths. Such a device is described in US 2002/164159 for sterilizing several types of products, such as cosmetic products, but the application of which is in particular for the sterilization of milk.

This device has drawbacks in that it is designed for sterilizing one single product. Indeed, the sterilization time is adapted here by increasing or decreasing the length of the circuit. One and the same installation can therefore be dedicated to only one single product having a given viscosity. Moreover, the sterilization time is very long, in the range of 80 minutes, through circulating in a Joule-effect tubular exchanger. The high temperatures combined with this long period oblige to use a high speed of circulation of the product, in the range of 5 metres per second.
Other solutions have been contemplated, for example in US 5 97 6 592, which use an electromagnetic field to irradiate the product and to thus heat it, then cool it down in a water-and-glycol bath at about 15 degrees Centigrade. Such a device is not fully satisfactory, namely because of the complexity and the cost of production and use. In addition, one and the same installation is dedicated to the sterilization of one and the same product having a given viscosity.
The object of the invention is to cope with the drawbacks of the state of the art by providing a method for manufacturing a cosmetic product that omits the addition of a preservative into the composition of a cosmetic product.
Moreover, one and the same installation permits to sterilize products having a different density or viscosity. By adapting the circulation pressure of the product, the present invention controls its sterilization time, i.e. the heating and the cooling.
To this end, the invention consists in sterilizing the cosmetic products through quickly bringing it at high temperature, followed by an immediate cooling through a specific device.
The invention thus relates to a method for sterilizing a cosmetic product, wherein said product is formed by a fluid circulated under regulated pressure, according to the viscosity of said fluid, in a sterilization circuit passing through baths of product brought at temperature. Such a method is characterized in that it consists m successively preheating said product in a preheating bath ; in quickly heating, during some seconds, said product in a bath at high temperature, then immediately and abruptly cooling said product in a cold glycol bath ; and in conditioning the product in a sterile atmosphere.
The invention also relates to the device for implementing such a sterilization method, which comprises a sterilization circuit capable of circulating a fluid under

regulated pressure successively through means for preheating said fluid in the form of a bath of product brought at temperature ; means for heating said fluid at high temperature in the form of a bath of product brought at high temperature ; means for cooling said fluid, in the form of a glycol bath, to means for conditioning in a sterile atmosphere.
Further features and advantages of the invention will become clear from the following detailed description of non-restrictive embodiments of the invention, with reference to the attached figure representing schematically the steps of the invention.
This invention relates to the sterilization of a cosmetic product and consists in sterilizing said cosmetic products at high temperature, followed by its immediate cooling.
The sterilization principle of the invention is close to the sterilization of a product in the agro-food field referred to as <( UHT » for ultra high temperature.
UHT sterilization consists in preheating a product, then in bringing it at high temperatures during a short period of time before cooling it at room temperature, the so treated product being then packaged aseptically.
The present invention thus consists in preheating the cosmetic product, beating it for a short period at high temperature, then cooling it.
A feature of the invention consists in that the cosmetic product is circulated in a sterilization circuit 1. The product is therefore no longer into contact with the outside during its sterilization and its packaging, thus avoiding any risk of contamination after sterilization.
The product conditioning is indeed carried out in a sterile atmosphere. This aseptic conditioning area 2 can preferably comprise a ceiling blowing filtered air. The product conditioning is performed under vacuum, without air input, in order to avoid any contaminant.
The sterilization circuit I is designed capable of circulating a fluid under pressure. To this end, said circuit 1 is in the form of a conduit 3 inside which the fluid is put under pressure from an inlet 4 to an outlet 5.
At the inlet 4, at one end of the conduit, are located the product supply and a punp 6 permitting the putting under pressure of said circuit 1.

At the outlet 5, at the opposite end of said conduit, at the level of the aseptic conditioning means 2 are located means for regulating the pressure 7, namely a regulating valve 35.
According to an embodiment, the sterilization circuit 1 comprises a coil inside which the cosmetic product fluid circulates. This coil can preferably have an inner diameter of 5 millimetres. Preferably, according to a particular embodiment, said circuit 1 is made of stainless material through a conduit having a diameter between 5 and 10 mm. The coil lengths in each of the baths, as mentioned hereinafter, are identical. In addition, the specific shape, namely a helical shape, ensures a heating and cooling homogenization inside the product circulating therethrough.
It should be noted that an essentia! feature of this invention thus consists in that the cosmetic product is obliged to be in the form of a fluid. The pressure inside the circuit 1 is regulated depending on its viscosity. Depending on the embodiment and the fluid inserted into the circuit 1, this pressure can vary between 8 and 160 bars, preferably between 80 and 120 bars. This high pressure ensures a better emulsion of the products, in particular of the cosmetic products,
The sterilization circuit 1 successively, but non-restrictively, passes through preheating means 8, heating means 9 and cooling means 10.
According to the preferred embodiment, these preheating 8, heating 9 and cooling 10 means are in the form of a bath of product brought at temperature, the temperature of the product depending on the type of bath, heating or cooling bath.
According to the preferted embodiment of the in^'ention, the cooling means 10 comprise a glycolyzed bath at -10 degrees Centigrade, the preheating means 8 comprise a bath at 90 degrees Centigrade, in order to ensure heating inside the product at least at 70°C, while the heating means 9 comprise a hot bath at 180 degrees Centigrade, in order to ensure heating inside the product at least at 135°C. However, the values of the temperatures of the various baths can singularly vary depending on the product to be sterilized.
In most cases, the temperature of the baths is maintained stable and only the time period during which the fluid passes inside said baths varies. The invention consists indeed in using the displacement of the product from one thermal area to another thermal area by regulating their time of exposure.

Passing through the bath at very high temperature is performed quickly, over a time period that does not exceed a few seconds. In particular, the time period for passing through the heating means 9 can be of 3 seconds.
The time period for the passing through can be regulated by varying the pressure, still as a ftunction of the viscosity of the fluid passing through the circuit 1.
The successive passing from a high temperatuue to a very low, preferably negative, temperature improves the sterilisation and preservation of the product. Indeed, even though the product itself does not pass over to a negative temperature, this abrupt cooling avoids the degradation of said product.
Finally, through a sterilization system similar to the so-called « UHT » method, the present invention can continuously treat, without interruption, cosmetic products of different viscosities, without any modification of the installation.
The sterilization method according to the invention will find a particular application within the framework of a range of cosmetic products based on thermal water. The sterilization at high temperature permits indeed to maintain the minerals and the oligo-elements present in the water. Namely the following products fall within this range : aqueous and cleaning lotions, cleaning gels, shampoos, oil-in-water emulsions, etc.
Obviously, the invention is not limited to the examples shown and described above, which can have variants and changes without departing from the framework of the invention.

CLAIMS
1. Method for sterilizing a cosmetic product, wherein said product is formed by
a fluid circulated under regulated pressure, according to the viscosity of said fluid, in a
sterilization circuit (I) passing through baths of product brought at temperature,
wherein the method consists in successively :
- preheating said product in a preheating bath ;
- quickly heating, during some seconds, said product in a bath at high
temperature, then immediately and abruptly cooling said product in a cold glycol bath ;
and
~ conditioning the product in a sterile atmosphere (2).
2. Device for implementing the sterilization method according to claim 1,
wherein the device comprises a sterilization circuit (1) capable of circulating a fluid
under regulated pressure successively through :
- means (8) for preheating sard fluid in the form of a bath of product brought at temperature ;
- means (9) for heating said fluid at high temperature in the form of a bath of product brought at high temperature ;
- means for cooling (10) said fluid, in the form of a glycol bath, to means for conditioning in a sterile atmosphere (2).

3. Device according to claim 2, wherein said circuit (1) is formed by a conduit (3) one end of which comprises means (6) for putting a fluid under pressure, while the other end comprises means (7) for regulating the pressure.
4. Device according to any of the claims 2 or 3, wherein the glycolyzed bath is at -10 degrees Centigrade.
5. Device according to any of the claims 2 to 4, wherein the bath of the preheating means (8) is at 70 degrees Centigrade.
6. Device according to any of the claims 2 to 5, wherein the hot bath of the heating means (9) is at 135 degrees Centigrade.