EP2370614B1 - Hollow glas article with metalized inner surface and process for obtaining such articles - Google Patents

Description

TECHNICAL AREA

The present invention relates to the general field of hollow bodies provided with an internal glass surface which can be used in various industrial sectors, such as for example the packaging sector (glass containers, of the flasks or jars type, intended to contain a substance. liquid or pasty, for example a cosmetic or pharmaceutical substance) or construction (hollow glass bricks). The invention also relates to the general technical field of the treatment of glass surfaces, for functional and / or decorative purposes.

The invention relates more precisely to a method of manufacturing a hollow body provided with an interior glass surface delimiting a cavity, as well as such a hollow body.

PRIOR TECHNIQUE

It is known to use glass containers to contain liquid products, in particular in the cosmetic, pharmaceutical or food industries. In particular, the use of glass for producing liquid perfume containers is particularly popular, given the noble character generally attributed to glass by consumers, and the objective qualities of transparency, robustness, and mechanical and chemical stability. of this material. This is why all or almost all liquid body perfumes, and in particular perfumes considered to be “ high-end ”, are contained in glass bottles.

The aesthetic qualities of a perfume bottle are also extremely important for the overall commercial attractiveness of a perfume. From this perspective, it is therefore essential to provide a perfume bottle whose aesthetics are very distinctly different from that of the bottles of the competition, and which is particularly attractive and enhancing for the perfume contained in the bottle.

This task is however made difficult for two main reasons.

The first of these reasons is due to the fact that glass is, by its very nature, a material which is particularly difficult to work with and to decorate under acceptable economic conditions, which is nevertheless essential in “ general public ” economic sectors such as perfume sector.

The second reason relates to the environment to which the glass constituting the perfume bottles is subjected and the general context of use of these bottles. In particular, the interior of a perfume bottle is in direct contact with the perfume itself, which usually consists of an alcoholic liquid. This means that any decoration placed on the inner surface of the bottle, in order to be visible by transparency from the outside to the consumer, must withstand being permanently and in the long term bathed in such an alcoholic solution, without disintegrating, disintegrate, decompose or dissolve, which is a real technical challenge. In addition to the catastrophic effects in terms of brand image that could cause a deterioration of an interior decoration of a bottle under the effect of its prolonged immersion in the liquid perfume, such deterioration could also lead to health problems insofar as the The composition of the perfume would be modified and would contain a more or less dispersed phase of the material which had previously constituted the decoration of the inner surface of the bottle. Thus, while it is extremely interesting, at least for aesthetic reasons, to decorate the internal surface of a glass bottle so that it is visible by transparency from the outside, such an internal decoration proves to be extremely difficult to achieve in practice taking into account the aggressiveness of the ambient alcoholic medium and the difficulty in making a coating stick to a glass substrate.

The document JP-2000129448 discloses a method according to the preamble of claim 1, and a hollow body according to the preamble of claim 16.

The document US-6,251,482 describes an example of the manufacture of a mirror in which glass sheets are first polished, rinsed and then sensitized by means of a solution of tin chloride, then rinsed. An acidic aqueous solution of PdCl ₂ is then sprayed onto the glass sheets. The glass sheets thus activated then pass to a rinsing station, then to a silvering station where a traditional silvering solution is sprayed so as to form, under conditions of conventional production, a layer containing about 800 to 850 mg / m ² of silver. The mass of silver deposited is greater by approximately 100 mg / m ² of silver, that is to say approximately 900 to 950 mg / m ² of silver. The glass is then rinsed, and directly after rinsing the silver coating, an acidified solution of freshly formed tin chloride is sprayed onto the silver glass sheets moving forward. Other steps are then implemented (spraying with a silane, rinsing, drying, covering with a Levis paint).

DISCLOSURE OF THE INVENTION

The objects assigned to the invention therefore aim to remedy the problem set out in the foregoing and to propose a new method of manufacturing a hollow body provided with an interior glass surface, making it possible to obtain a hollow body. particularly attractive from the aesthetic point of view.

Another object of the invention aims to provide a new method of manufacturing a hollow body provided with an interior glass surface, which makes it possible to obtain a particularly aesthetic hollow body and resistant to use, both from the point of view of mechanical and chemical point of view.

Another object of the invention is to provide a new method of manufacturing a hollow body provided with an interior glass surface, which makes it possible to obtain a particularly aesthetic hollow body extremely quickly and inexpensively.

Another object of the invention aims to provide a new method of manufacturing a hollow body provided with an interior glass surface, which is not only rapid but which also makes it possible to provide said hollow body with a particularly homogeneous decoration. and free from defects.

Another object of the invention aims to provide a new method of manufacturing a hollow body provided with an interior glass surface, making it possible to obtain a hollow body which is not only very aesthetic but is also extremely robust and durable. .

Another object of the invention aims to provide a new method of manufacturing a hollow body provided with an interior glass surface, making it possible to obtain a hollow body capable of stably and durably accommodating a fluid substance, and in particular a relatively aggressive fluid substance from the chemical point of view.

Another object of the invention is to provide a new hollow body provided with an interior glass surface having a particularly attractive appearance.

Another object of the invention aims to provide a new hollow body provided with an interior glass surface with a particularly elegant and sought-after decoration, and capable moreover of contributing to the preservation of any substance, in particular medicinal substance, capable of be contained in said hollow body.

Another object of the invention is to provide a new hollow body provided with an interior glass surface with a particularly rich and attractive decoration.

Another object of the invention aims to provide a new hollow body provided with an interior glass surface capable of reliably and durably containing a fluid substance, and in particular a relatively aggressive fluid substance from the chemical point of view.

The objects assigned to the invention are achieved by means of a method according to claim 1.

The objects assigned to the invention are also achieved with the aid of a hollow body according to claim 16.

SUMMARY DESCRIPTION OF THE DRAWINGS

• La figure 1 illustre, selon une vue schématique en perspective, un corps creux conforme à l'invention constitué en l'espèce par un flacon destiné à accueillir un parfum corporel liquide, ledit flacon étant fermé par un bouchon.
• La figure 2 illustre, selon une vue schématique en coupe, le flacon de la figure 1 ouvert.
• La figure 3 illustre, selon une vue schématique partielle en perspective, le principe de fonctionnement d'une machine susceptible de contribuer à la mise en œuvre du procédé conforme à l'invention.

Other objects and advantages of the invention will become more apparent on reading the description which follows, as well as with the aid of the appended drawings, given purely by way of illustration and without limitation, in which:

• The figure 1 illustrates, according to a schematic perspective view, a hollow body in accordance with the invention constituted in this case by a bottle intended to receive a liquid body perfume, said bottle being closed by a stopper.
• The figure 2 illustrates, in a schematic sectional view, the bottle of the figure 1 open.
• The figure 3 illustrates, in a partial schematic perspective view, the operating principle of a machine capable of contributing to the implementation of the method according to the invention.

BEST WAY TO MAKE THE INVENTION

The invention relates firstly to a method of manufacturing a hollow body 1 provided with an interior glass cavity 2 delimiting a cavity 3.

As shown in figures 1 and 2 , the hollow body 1 preferably constitutes a container 4 designed to contain a liquid or pasty substance in the cavity 3, and in particular an alcoholic liquid such as a body perfume. In this case, the container 4 is advantageously intended to be closed by means of a closure member 5, for example constituted by a stopper 5A.

The process according to the invention thus consists of a process for manufacturing a bottle intended to contain a liquid or pasty cosmetic substance, and preferably a perfumed alcoholic liquid. However, it is entirely conceivable that the process in accordance with the invention constitutes a process for manufacturing a bottle intended to receive a substance other than cosmetic, and for example a pharmaceutical substance, such as a drug.

Other applications, other than cosmetic or pharmaceutical, are of course conceivable. For example, the hollow body 1 can constitute a hollow glass brick, which can be used in construction and / or decoration, the process according to the invention consisting in this case in a process for manufacturing a hollow glass brick.

In what follows, for reasons of simplicity of description, only the manufacture of a perfume bottle will be detailed, purely by way of illustration and not by way of limitation.

The method according to the invention naturally comprises first of all a step of manufacturing or supplying a hollow body 1 provided with an interior surface 2 in glass delimiting a cavity 3. The term “ glass ” should be taken here in its classic meaning, and therefore designates a mineral glass. Preferably, this step of manufacturing or supplying the hollow body 1 with interior glass surface 2 consists of manufacturing or supplying a single-piece hollow body, entirely made of glass, within which the glass is formed. cavity 3. In other words, the hollow body 1 is constituted by a single part manufactured in a single block, for example by a blowing or molding process. The production of such a hollow glass body, in particular when said hollow body constitutes a bottle, is perfectly known as such and can be obtained by any conventional glass process. Of course, the fact that the hollow body 1 delimiting the cavity 3 is made in one piece, and not by assembling independent parts, makes it all the more difficult to decorate the inside of the hollow body 1, in particular when this the latter is provided with a neck (in the case of a bottle for example) which further restricts access to cavity 3.

The hollow body 1 is therefore, as explained in the foregoing, provided with a cavity 3 delimited by an interior surface 2, that is to say that the hollow body 1 is hollowed out and as such defines an empty volume in her breast. Preferably, the hollow body 1 is shaped so that the cavity 3 forms a constriction 6 defining an opening 7 allowing the cavity 3 to be placed in communication with the outside, said opening 7 preferably being intended to cooperate with said closure member 5. to close the hollow body 1 when the latter constitutes a container 4. In this case, the cavity 3 forms an empty interior volume which is entirely closed, with the exception of an opening 7 towards the exterior, the section of which is reduced compared to the average section of the cavity 3, as illustrated in the figure Such a configuration is characteristic of a bottle provided with a neck, that is to say a narrow neck making it possible to put the inside of the bottle in communication with the outside.

In accordance with the invention, the method further comprises a step of covering at least a fraction of the interior surface 2 with a coating 8 of predominantly metallic composition. It is also conceivable, in order to obtain specific aesthetic effects, for the composition of the coating 8 to include a (minority) fraction of a dye, for example in the form of a colored pigment dispersed homogeneously in the coating. coating 8, mixed with the metal mainly constituting the latter.

Preferably, the covering step is designed so that substantially all of the interior surface 2 is covered by the coating 8 of predominantly metallic composition, as illustrated in figure 2 . However, it is quite conceivable, without departing from the scope of the invention, that only a fraction of the interior surface 2, that is to say of the surface located opposite the empty volume forming the cavity 3, or covered by the coating 8 in question.

Preferably, the coating 8 is of substantially entirely metallic composition, and is preferably constituted by a shiny metal capable of providing a reflecting effect (“ mirror ” effect) such as silver, and to a lesser extent gold, gold. nickel, platinum, zinc and copper. It is in particular perfectly conceivable that, advantageously, the coating 8 is predominantly or even exclusively composed of gold. Such a gold coating, seen from the outside through the transparent wall of the hollow body 1, in fact provides a quite remarkable aesthetic result, the gold being moreover tolerable by the human organism so that it can be placed in direct contact with the substance likely to be contained by the cavity 3 (perfume for example).

Alternatively, it is also conceivable that the coating 8 is advantageously composed of a precious metal (noble metal), such as palladium, rhodium, ruthenium or osmium for example, or of another non-precious metal such as tin or cobalt. The covering of the inner surface 2 with such a coating of predominantly metallic composition makes it possible to decorate the hollow body 1 in a particularly original way, insofar as the metallic coating 8 is advantageously visible by transparency through the wall 1A of the hollow body 1 forming the inner surface 2. The inner surface 2 can be made of transparent white glass, it being understood that colored and / or translucent glass can also give good aesthetic results. The characteristics of the glass used, in particular its nature and its thickness, can advantageously influence the original aesthetic effects conferred by the coating 8.

In addition, the predominantly metallic character of the coating 8 can impart specific functional properties to the hollow body 1 which is provided with it on its inner surface 2. For example, a coating 8 essentially composed of silver allows to impart microbicidal properties to the interior surface 2, which proves to be particularly useful in the pharmaceutical sector.

Advantageously, the method in accordance with the invention comprises a washing step, preferably with demineralized water, of the interior glass surface 2, of the hollow body 1. Preferably, this washing step is carried out using a rinsing liquid (preferably demineralized water) whose pH is substantially greater than or equal to 5, and even more preferably to 5.5. The choice of such a pH proves to be particularly beneficial because it makes it possible to substantially avoid, in particular when covering with a silver-based coating 8 is implemented, a phenomenon of degradation of the deposited silver layer. on the inner surface 2.

Then, the recovery step mentioned in the above is implemented.

Advantageously, this covering step firstly comprises a sub-step for activating the inner surface 2, in order to thus obtain an activated inner surface 2, that is to say which is more chemically reactive than the inner surface. 2 gross. Preferably, this activation sub-step makes it possible to increase the surface energy of the interior glass surface 2 in order to promote the chemical reactivity of the latter. Preferably, the activation substep is carried out by bringing the inner surface 2 into contact with a solution of tin chloride (SnCl ₂ ) as an activating agent (also called an activating agent), the chloride tin proving to be particularly suitable for the implementation of a process aimed at coating the inner surface 2 with a silver coating. Advantageously, bringing the inner surface 2 into contact with the tin chloride solution forming an activation solution consists in filling the cavity 3 with the tin chloride solution for a time sufficient to allow the activation of the. interior surface 2 and get an interior surface 2 activated. Preferably, the activation sub-step is carried out by direct contact of the activation solution with the inner surface 2, that is to say in the absence of any intermediate layer (primer layer for example) covering the interior glass surface 2.

Subsequently, once the interior surface 2 is activated, the tin chloride solution is discharged out of the cavity 3. Alternatively, bringing the interior surface 2 into contact with the activation solution (in the occurrence of tin chloride) consists of spraying the tin chloride solution onto the interior surface 2, that is to say spraying said tin chloride solution onto the interior surface 2 in the form of fine droplets (spray). Such vaporization can for example be carried out using a projection nozzle introduced into the hollow body 1 (for example through the opening 7 if said hollow body forms a bottle provided with the opening 7 in question, preferably by the constriction 6 and beyond the latter), a relative rotational and translational movement of the hollow body 1 and of the nozzle being implemented so that the tin chloride solution is sprayed uniformly and homogeneously over the entire interior surface 2 to be treated, regardless of the shape of the cavity 3 defined by the interior surface 2. Bringing the interior surface 2 into contact with the tin chloride solution by vaporization of the latter is particularly advantageous because it allows rapid industrialized treatment, with a quantity of tin chloride solution much lower than that required for the implementation of the other contacting method described above.

Whatever method is used to bring the interior surface 2 into contact with the tin chloride solution, a sufficient contact time should be observed (for example of the order of ten or fifteen seconds) between the inner surface 2 and the tin chloride solution before continuing the process. Compliance with this waiting time makes it possible to limit the presence of aesthetic defects in the coating 8 and to optimize the strength and the mechanical and chemical stability of said coating 8 on the interior surface 2. The covering step then advantageously comprises , after the waiting time mentioned above, a sub-step of rinsing the activated interior surface 2, to remove any residues from the activation solution (which preferably consists of a solution of chloride of tin, as discussed in the above).

In one embodiment, the activated interior surface 2 comprises an activating layer (not shown) formed by the activating agent at least partially covering the interior surface 2. In an alternative embodiment, the step of activation makes it possible to create not an activation layer but activation points (not shown) constituted by the activating agent distributed discretely, and preferably evenly, on the interior surface 2. Advantageously, step covering subsequently comprises a sub-step of grafting said inner surface 2 activated with a grafting agent, thereby obtaining a grafted inner surface 2.

The grafting sub-step thus makes it possible to chemically graft a grafting agent onto the activated inner surface 2, by chemical reaction between the grafting agent and the activated inner surface 2, said reaction leading to the formation of chemical bonds between the. grafting agent and the inner surface 2 activated. In other words, the grafting sub-step allows the establishment of chemical bonds between the grafting agent and the activating agent. Alternatively, it is also conceivable that the grafting solution comes to cling directly to the inner surface 2. Advantageously, in particular in the case of a process aimed at coating the inner surface 2 with a coating 8 in silver, the grafting agent is based on palladium. Advantageously, the grafting sub-step comprises bringing the activated inner surface 2 into contact with a grafting solution, which preferably consists of a solution of palladium chloride (PdCl ₂ ). Particularly advantageously, this bringing the activated inner surface 2 into contact with a grafting solution is carried out by filling the cavity 3 with said grafting solution, and preferably by completely filling (to the brim) of said cavity 3. .

Preferably, the filling of the cavity 3 with the grafting solution is carried out in an automated manner. Thus, in a particularly advantageous embodiment, this filling is carried out using a filling machine (filling machine) comprising, as illustrated in figure 3 , a central nozzle 9 through which passes and flows the grafting solution (preferably consisting of a solution of palladium chloride) towards and in the cavity 3, and a peripheral suction nozzle 10, concentric and coaxial with the central nozzle 9, intended to suck up any overflow of grafting solution. More precisely, the double nozzle is intended to come into contact with the opening 7 giving access to the cavity 3 so that the peripheral suction nozzle 10, the diameter of which is adapted to that of the opening 7, prevents a possible overflow of the grafting solution out of the container 4. To this end, the introduction of the grafting solution through the central nozzle 9 and the suction through the peripheral nozzle 10 are preferably carried out simultaneously. Advantageously, the double nozzle is designed to allow direct contact of the grafting solution with the interior surface 2 whatever the shape of the hollow body 1, in particular if it constitutes a bottle 4 with a constriction 6.

The implementation of such a filler, which moreover constitutes an invention as such, independently of the other aspects described here, allows a considerable gain in productivity, since it allows, as an indication, to treat about 5 bottles. (capacity equal to 130 ml) per minute instead of 0.3 vial per minute in the context of a process implemented manually. Once the container 4 has been filled, preferably completely, with the palladium chloride solution, the latter is left inside the container 4, in contact with the internal glass surface 2, for a contact time sufficient to achieve chemical bonds between the activating agent present superficially on the activated interior surface 2 and the grafting agent contained in the grafting solution.

In one embodiment, the grafting agent is designed to form a grafting layer (not shown) which advantageously covers, at least partially, the activating agent (which is in the form of a layer of activation or a distribution of activation points) which is attached directly to the interior surface 2. The interior surface 2 is thus covered, at least in part, by said activation and grafting layers, which are preferably superimposed. The grafting step allows the grafting agent to form chemical bonds with the activating agent at the activation points (or layer) present on the inner surface 2, so that s 'establish chemical bonds between the activating agent and the grafting agent to form attachment points for the metallic coating. For example, in the preferred embodiment example aiming to produce a silver coating 8, the palladium chloride solution is left for a sufficient contact time (for example of the order of about twenty or thirty. seconds) to make bonds between palladium and tin.

At the end of this period of contacting, the hollow body 1, constituted in the example illustrated in the figures by the container 4, is emptied, that is to say that the grafting solution is discharged out of the cavity 3. Advantageously, the method according to the invention comprises a step of recovering the grafting solution after its brought into contact with the activated interior surface 2, insofar as this recovered solution can be used again to graft another interior surface of another hollow body. As an indication, a quantity of approximately 2 ml of palladium is necessary to treat a vial whose capacity, that is to say the volume of cavity 3, is 130 ml.

Alternatively, bringing the activated interior surface 2 into contact with the grafting solution (in this case palladium chloride) consists of spraying the palladium chloride solution onto the activated interior surface 2, that is, that is to say in spraying said solution of palladium chloride on the activated interior surface 2 in the form of fine droplets (spray). Such vaporization can for example be carried out using a projection nozzle introduced into the hollow body 1 (for example through the opening 7 if said hollow body forms a bottle provided with the opening 7 in question, preferably by the constriction 6 and beyond the latter), a relative rotational and translational movement of the hollow body 1 and of the nozzle being implemented so that the palladium chloride solution is sprayed uniformly and homogeneously on the entire interior surface 2 activated to be treated. Bringing the activated interior surface 2 into contact with the palladium chloride solution by vaporization of the latter is particularly advantageous because it allows rapid industrialized treatment, with a quantity of palladium chloride solution much less than that required for the setting. implementation of the other contacting method described above.

Whatever method is chosen to bring the interior surface 2 into contact with the tin chloride solution, a sufficient contact time should be observed (for example of the order of about thirty seconds in the case of where the solution is vaporized) between the inner surface 2 and the tin chloride solution before continuing the process. Compliance with this waiting time makes it possible to limit the presence of aesthetic defects in the coating 8 and to optimize the strength and the mechanical and chemical stability of said coating 8 on the inner surface 2. Advantageously, the process in accordance with The invention comprises, after the grafting sub-step, a step of rinsing the grafted interior surface 2 to remove the residues of the grafting solution. For example, when the grafting solution is consisting of a solution of palladium chloride, the rinsing step removes chlorine residues and leaves only the palladium on the interior surface 2.

The activation sub-step is implemented before the grafting sub-step, as described above, so as to obtain an interior surface 2 which is activated and then grafted. Alternatively, the grafting sub-step is advantageously carried out before said activation sub-step or simultaneously with the latter. Whatever the chronology of said activation and grafting sub-steps, the latter lead to the formation, on the inner surface 2, of anchoring points for the metallic coating 8, said anchoring points being composed of agents of 'activation and grafting, which are advantageously linked together.

• une opération de mise en contact de la surface intérieure 2 greffée avec une solution renfermant des ions métalliques, de préférence des ions argent,
• et une opération d'introduction d'un agent réducteur, constitué de préférence par un gluconate, dans ladite solution renfermant des ions métalliques (de préférence des ions argent), alors que cette dernière est en contact avec la surface intérieure greffée, pour transformer les ions métalliques en métal (de préférence en argent) qui s'accroche à l'agent de greffage (qui est de préférence du palladium) présent superficiellement sur la surface intérieure 2.

The activation and grafting sub-steps are preferably carried out using filling nozzles which have the advantage of allowing efficient and simple covering of the interior surface 2 of any type of hollow body 1, regardless of its shape and even in the presence of a constriction 6 forming a neck opening onto the opening 7. Advantageously, these two sub-steps, simultaneous or consecutive, make it possible to obtain an interior surface 2 comprising points of attachment to the surface glass which facilitate and improve in a particularly effective way the adhesion of the metal on the glass. Advantageously, the covering step implemented in the method according to the invention comprises a metallization sub-step making it possible to obtain a metallized inner surface, said metallization sub-step itself comprising:

• an operation of bringing the grafted interior surface 2 into contact with a solution containing metal ions, preferably silver ions,
• and an operation of introducing a reducing agent, preferably consisting of a gluconate, into said solution containing metal ions (preferably silver ions), while the latter is in contact with the grafted interior surface, in order to transform the metal ions of metal (preferably silver) which clings to the grafting agent (which is preferably palladium) present superficially on the inner surface 2.

• une opération de mise en contact de la surface intérieure 2 greffée avec une solution d'agent réducteur, constitué de préférence par un gluconate,
• et une opération d'introduction d'ions métalliques, de préférence des ions argent, dans ladite solution d'agent réducteur, alors que cette dernière est en contact avec la surface intérieure greffée, pour transformer les ions métalliques en métal (de préférence en argent) qui s'accroche à l'agent de greffage (qui est de préférence du palladium) présent superficiellement sur la surface intérieure 2.

It is however quite possible, as an alternative, for said metallization sub-step to be carried out in reverse, that is to say that it comprises:

• an operation of bringing the grafted interior surface 2 into contact with a solution of reducing agent, preferably consisting of a gluconate,
• and an operation of introducing metal ions, preferably silver ions, into said reducing agent solution, while the latter is in contact with the grafted interior surface, to transform the metal ions into metal (preferably silver ) which clings to the grafting agent (which is preferably palladium) present superficially on the inner surface 2.

Advantageously, the operation of bringing the grafted interior surface 2 into contact with the solution containing metal ions, for example in the form of at least one metal salt, is carried out by filling, possibly complete (to the brim) of the cavity 3 with said solution containing metal ions. The reducing agent, which is preferably a gluconate, is then introduced into the solution filling the cavity 3 in order to convert the metal ions (consisting for example of silver Ag ⁺ ions) into metal (consisting for example of silver) which will be attached to the grafting agent (consisting for example of palladium, which gives excellent results in order to obtain a silver coating 8).

As an indication, the solution containing metal ions preferably contains, in the case of a solution intended to produce a silver coating 8, approximately 2 ml of silver for a flask to be treated, the capacity of which (volume of the cavity 3) is approximately 130 ml. Preferably, said solution containing silver ions comprises at least silver nitrate (AgNO ₃ ). Carrying out the metallization by subjecting the interior surface 2 to a liquid solution proves to be particularly advantageous from an industrial point of view, because of its simplicity and its competitive cost.

In particular, this metallization by simply filling the bottle with different solutions (activation solution, grafting solution and metallization solution) does not require any complex and expensive industrial means, and only requires basic and robust equipment, which can be easily automated. As a result, the process according to the invention exhibits, in its most advantageous embodiments described in the foregoing, excellent industrial efficiency, with high productivity. high allowing high production rates and a relatively low cost price, for an excellent result, in particular aesthetic. In particular, the vaporization of said activation and grafting solution using a nozzle 9 facilitates the implementation of the method of the invention, whatever the shape of the hollow body 1, in particular if it comprises a throttling 6. Activation and grafting, in particular with tin and palladium, allow excellent adhesion of the metal to the glass without altering the appearance of said metal (no yellowing or loss of shine). These activating and grafting agents, advantageously always present at the end of the process and form a fixing interface between the interior glass surface 2 and the metallic coating 8. Advantageously, the covering step comprises, before implementation of the metallization sub-step, a sub-step of baking the hollow body 1 (that is to say in this case of the container 4) aimed at raising the temperature of the interior surface 2.

For example, in the context of a process for covering the inner surface 2 with a layer of silver (with a solution of tin chloride as an activation solution and a solution of palladium chloride as a grafting solution), this baking sub-step is preferably carried out at a temperature substantially between 20 and 100 °, preferably around 80 ° C, so that the hollow body 1 leaves the oven at a temperature preferably between 30 and 80 ° C, and for example substantially equal to 60 ° C. The metallization sub-step is then carried out on the hollow body 1 (that is to say the bottle in the example illustrated in the figures) while still hot, which makes it possible to accelerate the reduction reaction which transforms the silver ions. in metallic silver. Thus, thanks to the steaming step which makes it possible to bring the flask for example to around 60 ° C, the reaction of transformation of the silver ions into metallic silver can only last about twenty seconds while at room temperature ( about 20 ° C) it could have lasted much longer (for example about 1 hour).

Advantageously, the metallization sub-step also comprises an operation of stirring, preferably mechanized, of the grafted interior surface 2, while it is in contact with said solution containing both the metal ions and the reducing agent, to obtain a substantially homogeneous metal deposit on the interior surface 2 grafted. In other words, the hollow body 1, that is to say advantageously the container 4 is stirred, shaken, so that the metal resulting from the reduction reaction is distributed evenly over the entire interior surface 2 concerned. Thus, in the specific embodiment aiming to cover the interior surface 2 with silver, the stirring operation makes it possible to obtain a silver coating on the interior surface 2, the thickness E _{1 of which} is particularly uniform over the entire surface. treated surface. As indicated in the above, the stirring operation is preferably mechanized, or even automated, using conventional means making it possible to hold the bottle 4 and to shake it. This does of course absolutely not exclude that the stirring operation can be carried out manually. However, the implementation of a mechanized stirring allows a significant gain in productivity, since combined with the implementation of an automated filling of grafting solution (using a filler, as explained in the above ), it turns out to be possible to treat ten vials (with a capacity of 130 ml) per minute, while reducing the quantities of solution containing metal ions and reducing agent. Thus, it is possible to obtain, with the aid of very simple operations of filling and stirring the container 4, a particularly homogeneous, resistant and decorative metal layer on the inner surface 2 of said container 4, whatever the shape of this latest.

The metallization sub-step is carried out so that the inner wall 2 is covered by the coating 8 in a surface quantity greater than or equal to 1000 mg / m ² . In an advantageous embodiment, the surface quantity is substantially greater than or equal to 1500 mg / m ² , preferably substantially greater than or equal to 2000 mg / m ² .

The use of such a surface quantity for the coating 8 advantageously makes it possible to obtain a reflective and opaque coating 8, without having to resort to additional layers. Obtaining these reflective and opaque characters is particularly appreciable from an aesthetic point of view, and also makes it possible to advantageously contribute to preserving the qualities of the liquid or pasty substance contained in the hollow body 1, in particular when it is acts of perfume, preventing the light from reaching it. The use of such a surface amount also allows the coating to be properly maintained on the inner surface 2, without significant risk of untimely detachment.

A surface quantity of metal approximately equal to 1,200 mg / m ² is very particularly preferred, both in terms of decorative effect and of mechanical and chemical resistance. The value of 1200 mg / m ² proves to be particularly optimal in the case of a process aimed at covering the inner wall 2 with a silver coating 8.

Advantageously, the metallization sub-step comprises a final operation of emptying the cavity 3 consisting in evacuating the solution containing the metal ions and the reducing agent from the bottle. The solution thus recovered can optionally be reused for the metallization of another interior surface 2 of another bottle.

Preferably, the emptying operation in question is only carried out once the solution contained in cavity 3 (mixture of solutions containing silver ions and of a reducing agent) has a clear, translucent appearance, indicative of the completion of the chemical reaction and therefore of the recovery process. Advantageously, the metallized inner surface 2 is then washed to remove the residues of the reducing agent.

Advantageously, the method according to the invention finally comprises a baking step, subsequent to the metallization sub-step, in which the metallized inner surface 2 is baked in order to dry and harden the metal film present on the inner surface 2 as a consequence of the implementation of the metallization sub-step, said metallic film constituting the coating 8.

For example, in the case of a process aimed at covering the inner surface 2 with a layer of silver, the bottle 4 with its metallized inner surface 2 is fired at a temperature of between substantially 50 and 300 ° C, preferably about 180 ° C, for about 30 minutes, which results in a dry and hard silver film on the inner surface 2. The silver coating 8 thus obtained is extremely sturdy attached to the inner surface 2 of the. vial, and satisfies the so-called “ adhesive tape resistance ” test consisting of applying a piece of adhesive tape to the coating 8 covering the inner wall 2, then removing this adhesive tape without the adhesive being significantly torn off. 8 silver coating.

The coating obtained also withstands the so-called “ pencil point ” test, that is to say that it is not appreciably scratched when it is scratched by the lead of a pencil. 5H hardness paper. Finally, it has been observed that a silvery coating 8 obtained in accordance with what is explained in the foregoing perfectly tolerates being brought into contact for a long time with an alcoholic liquid, and in particular with a perfume. In particular, a silver coating deposited on the inner surface 2 of a glass bottle, in accordance with the method according to the invention, proves to be quite stable when it is immersed in an alcoholic juice for at least six months at temperature. ambient, and for at least three months at 45 ° C. Additional steps can moreover be optionally implemented at the end of the cooking step. Thus, it is conceivable to cover the metal coating 8 with a film of varnish for decorative and / or protective purposes.

It is also conceivable, once the coating 8 has been produced, to draw a decorative pattern on the latter by removing the metal using a laser beam. In this case, the laser beam advantageously takes its source outside the hollow body 1 and passes through the wall 1A of the latter to reach the coating 8 from the outside of the hollow body 1 to modify, preferably eliminate, at least partly said coating 8.

It is thus possible to remove, at least partially, the coating 8 in order to create an aesthetic decorative pattern created from the differences between the inner surface 2 covered by the coating 8 and that not covered. In order to achieve this targeted and controlled removal of said coating 8, it is possible for example to use a fiber laser, for example an Nd-Yag type laser, placed outside the hollow body 1 and emitting a laser beam capable of passing through the wall. 1A.

Other optional additional steps can also be implemented before the step of covering with the coating 8. For example, the method can advantageously comprise, at its start, a prior operation of coloring the interior surface 2, by covering with the latter with a colored layer, by any means known in the field, in order to obtain a colored interior surface 2.

The step of covering with the coating 8 is then carried out on this colored interior surface 2, which leads to obtaining an interior surface 2 covered with a stack of two successive layers, namely a colored layer and a coating 8 of predominantly metallic composition. Such an interposition, between the inner surface 2 and the coating 8, of a colored layer, makes it possible to obtain a particularly original and attractive aesthetic result.

In addition, the method of the invention can advantageously comprise a sub-step of protecting said coating 8 by a protective layer (not shown) which comes into direct contact with the liquid or pasty substance contained in said hollow body 1. The protective layer On the one hand protects said coating 8 from any incompatibility with said liquid or pasty substance, and on the other hand said liquid or pasty substance from any risk of altering its properties on contact with said coating 8.

The protective layer is composed, for example, of a vitreous layer obtained by a sol-gel process, of a varnish, of a protective lacquer, of metal oxides or of a plastic material obtained by plasticization.

It is also particularly advantageous to proceed, just before the firing step and after the metallization sub-step, to wiping the hollow body 1 with a view to eliminating any dirt, droplets or various traces present on the hollow body 1. In fact, after the cooking step, such defects are transformed into inclusions and irremediable aesthetic defects which it is impossible to correct.

In the foregoing, the process has been described essentially with regard to a preferred variant aiming to cover the interior surface with silver 2. However, the process can be implemented with other metals, such as gold, copper, nickel, zinc or platinum, for example, by adapting in particular the nature and composition of the activating and grafting agents and the reducing agent.

Advantageously, the manufacturing process of the invention comprises substantially identical steps whatever the nature of the metallic coating.

In particular, the following first comparative table indicates, purely by way of illustration, examples of processes in accordance with the invention making it possible to obtain a metallic coating 8 comprising silver, copper (copper 1 or copper 2), gold or nickel: <u> Table 1 </u> STEP SILVER COPPER COPPER II GOLD NICKEL 1 Rinsing Rinsing Rinsing Rinsing Rinsing 2 Activation Activation Activation Activation Activation 3 Rinsing Rinsing Rinsing Rinsing Rinsing 4 Grafting Grafting Grafting Grafting Grafting 5 Rinsing Rinsing Rinsing Rinsing Rinsing 6 Steaming at 30-80 ° C Steaming at room temperature Steaming at room temperature Steaming at room temperature Steaming at room temperature 7 Metallization: introduction of the metal salt solution Metallization: Introduction of the metal salt solution Metallization: Introduction of the metal salt solution Metallization: Introduction of the metal salt solution Metallization: Introduction of the metal salt solution 8 Metallization: Introduction of the reducing solution Metallization: Introduction of the reducing solution Metallization: Introduction of the reducing solution Metallization: Introduction of the reducing solution Metallization: Introduction of the reducing solution 9 Shaking and partial filling of the bottle Shaking and partial filling of the bottle Shake and fill the bottle completely Shaking and partial filling of the bottle Shake and fill the bottle completely 10 nothing nothing Heating to 30-90 ° C nothing Heating to 30-90 ° C 11 Emptying Emptying Emptying Emptying Emptying 12 Rinsing Rinsing Rinsing Rinsing Rinsing 13 Cooking at 50 - 180 ° C Cooking in a neutral atmosphere Cooking in a neutral atmosphere Cooking at 50 - 180 ° C Cooking at 50 - 180 ° C

This first table makes it possible to highlight the process steps which are substantially identical from one metal to another.

The following second comparative table specifies the products and the reagents advantageously used during the steps described in the first table: <u> Table 2 </u> COMPONENTS STEP SILVER COPPER I COPPER II GOLD NICKEL Metallic salt 7 Ag ⁺ Cu ²⁺ or Cu ⁺ Cu ²⁺ or Cu ⁺ Au ⁺ or Au ³⁺ Neither ²⁺ Complexing agent 7 EDTA and other amino complexing agents, rochelle salt, gluconate, organic acids, ammonia, organic acids Reducing agent 8 Formaldehyde, gluconate, hydrazine, hydroxylamine, dimethylamine borane, borohydride, glyoxylic acid, hypophosphorous acid or its salts

Preferably, the metal salt is mixed with a complexing agent in solution in order to facilitate the subsequent reduction reaction. The complexing and reducing agents indicated in the second table are given purely as an indication and it is also perfectly conceivable to deposit the metal with several complexing agent - reducing agent pairs. There are also other reducing agents which are particularly effective and can lead to the reduction of metal salts. Likewise, there is a wide range of complexing agents which can be used with the metal salt solution for the reduction reaction.

Depending on the reducing agent chosen, the pH is adjusted to be within the operating range of the reducing agent.

These two tables therefore present a few examples of implementation of the process of the invention, which may also include other optional steps, such as those described above (protective layer, cutting of the coating, etc.).

The invention also relates as such to a hollow body 1 capable of being obtained by the method in accordance with the invention described in the foregoing, and preferably directly obtained by the method in question.

As explained previously, the hollow body 1 is provided with an interior surface 2 made of glass defining a cavity 3, at least a fraction of which is covered by a coating 8 of predominantly metallic composition.

Preferably, the coating 8 is mainly made of a metal taken from the following group: silver, gold, copper, nickel, zinc, platinum. The metallization of the inner surface of the hollow body 1 makes it possible to obtain, as explained in the above in relation to the process, an excellent decorative effect. In particular, the coating 8 is advantageously visible by transparency through the wall 1A delimiting the cavity 3. The inner face of this wall 1A corresponds to the inner wall 2 on which the coating 8 is deposited. This wall 1A also has an outer face. opposite 11 on which it is possible to affix, by any known means, a marking 12, and preferably a marking 12 for decorative purposes. The marking 12 is thus separated from the metallic coating 8 by the thickness E ₂ of the wall 1A defining the cavity 3. The marking 12 is thus reflected on the coating 8, in particular when the latter is a silver coating which provides an excellent. "mirror " effect, so that the user perceives both the marking 12 but also its distant reflection 13 and / or its shadow on the coating 8, which is particularly attractive from an aesthetic point of view. For example, the marking 12 can be produced by screen printing, the screen printing operation being followed by baking which also contributes to reinforcing the strength and stability of the coating 8.

Another possibility for reinforcing the mechanical strength and the chemical stability of the coating 8 consists in the implementation of an optional step of hot spraying (that is to say on the heated hollow body 1) of a metal oxide. (for example titanium oxide in solution) on the coating 8, for example after the baking step. Plasma deposition of the metal oxide is also possible. This operation of covering the coating 8 with a metal oxide makes it possible to improve the “ resistance to juice ” of the coating 8. Advantageously, the coating 8 covers the internal surface 2 with a basis weight substantially greater than or equal to 800 mg / m ² , and preferably substantially greater than or equal to 1000 mg / m ² , a value approximately equal to 1200 mg / m ² being preferred for reasons of strength and aesthetics, in particular when the coating consists predominantly of silver.

Preferably, the interior surface 2 is substantially completely covered by the coating 8, as illustrated in figure 2 , while the thickness E _{1 of} said coating 8 is advantageously substantially uniform. However, it is entirely conceivable that only a fraction of the inner surface 2 is covered by the coating 8, such a selective covering being obtained for example by temporary masking of the fraction of the inner surface 2 which is not intended to be covered by the coating 8. It is thus conceivable that the non-covered areas of the inner surface 2 draw a decorative pattern. Alternatively, it is also perfectly possible for part of the coating 8 to be cut using a laser beam as mentioned above.

Advantageously, the hollow body 1 in accordance with the invention comprises a single piece of glass within which the cavity 3 is formed. The hollow body 1 is also preferably designed to be gripped and handled by hand.

In a particularly preferred variant, and as explained in the above, the hollow body 1 according to the invention preferably constitutes a container 4 designed to contain a liquid or pasty substance in the cavity 3, and in particular an alcoholic liquid such as a body perfume, said container being intended to be closed using a closure member 5. More precisely, the cavity 3 advantageously forms a constriction 6 defining an opening 7 making it possible to put the cavity 3 in communication with the outside , said opening 7 being intended to cooperate with the closure member 5, preferably constituted by a plug 5A, to close said container. Advantageously, the hollow body 1 thus constitutes a bottle 4, which comprises a constriction 6 forming a neck at the level of its opening 7, intended for the storage and distribution of a liquid body perfume, it being understood that the hollow body 1 is preferably designed so that the coating 8 is in contact, and preferably in direct contact, with said liquid or pasty substance. In other words, the hollow body 1 is designed so that the coating 8 itself directly defines the cavity 3, that is to say that it forms the outermost layer of the inner wall 2, intended to be in contact with the substance contained in said cavity 3. It is however entirely conceivable, according to an alternative embodiment already mentioned in the above from the point of view of the method, that the coating 8 is itself covered with a protective layer, for example based on metal oxides (titanium oxide for example).

POSSIBILITY OF INDUSTRIAL APPLICATION

The invention finds its industrial application in the design and manufacture of hollow bodies provided with an interior glass surface which can be used in various industrial sectors, in particular in the packaging or construction sector.

Claims (22)

1. A method of manufacturing a hollow body (1) provided with a glass inside surface (2) defining a cavity (3), said body (1) constituting a container (4), said method including a step of covering at least a fraction of said inside surface (2) with a metal lining (8), characterized in that said hollow body (1) comprises a single piece of glass inside which said cavity (3) is formed and constituting a container (4) designed for containing in the cavity (3) a cosmetics substance formed by an alcoholic liquid such as a body perfume, the inside surface (2) being covered with the lining (8) in a quantity per unit area that is equal to or greater than 1000 mg/m², said covering step including a sub-step of activating said inside surface (2) by putting the inside surface (2) into contact with an activation agent, so as to obtain an activated inside surface (2), and thereafter a sub-step of grafting said activated inside surface (2) with a grafting agent, in order to obtain a grafted inside surface (2).
2. A method according to the preceding claim, characterized in that the wall (1A) of the hollow body (1) has an inside face corresponding to the inside surface (2) on which the lining (8) is deposited, and also has an opposite outside face (11) on which a marking (12) is placed, which is thus separated from the lining (8) by the thickness (E₂) of the wall (1A) defining the cavity (3).
3. A method according to the preceding claim, characterized in that the marking (12) is achieved by screen-printing, followed by baking.
4. A method according to one of the preceding claims, characterized in that the inside surface (2) is covered with the lining (8) in a quantity per unit area that is equal to or greater than 1500 mg/m², preferably equal to or greater than 2000 mg/m².
5. A method according to one of the preceding claims, wherein the activation agent is a tin chloride solution.
6. A method according to one of the preceding claims, wherein said putting the inside surface (2) into contact with the activation agent consists in spraying in the form of fine droplets said activation agent in solution onto the inside surface (2).
7. A method according to one of the preceding claims, wherein said grafting sub-step comprises putting the activated inside surface (2) into contact with a grafting solution, which is constituted by a palladium chloride solution.
8. A method according to the preceding claim, wherein the putting the activated inside surface (2) into contact with the grafting agent consists in spraying in the form of fine droplets the grafting solution onto the activated inside surface (2).
9. A method according to one of the preceding claims, wherein said covering step includes a metal-plating sub-step making it possible to obtain a metal-plated inside surface (2), said metal-plating sub-step itself including:

   - an operation of putting the grafted inside surface (2) into contact with a solution containing metal ions, and preferably silver ions;

   - and an operation of introducing a reducing agent into said solution containing metal ions, while said solution is in contact with the grafted inside surface (2), so as to transform the metal ions into metal that keys onto the grafting agent.
10. A method according to the preceding claim, characterized in that, prior to implementing the metal-plating sub-step, the covering step includes a sub-step of stoving the hollow body (1) for the purpose of raising the temperature of the inside surface (2), the metal-plating sub-step being then conducted on the hollow body (1) that is still warm.
11. A method according to claim 9 or 10, wherein the metal-plating sub-step also includes an operation of mechanically agitating the grafted inside surface (2), while said surface is in contact with said solution containing both the metal ions and the reducing agent, so as to obtain a metal deposit that is uniform over the grafted inside surface (2).
12. A method according to one of claims 9 to 11, which includes a baking step, subsequent to the metal-plating sub-step, in which baking step the metal-plated inside surface (2) is baked so as to dry and to harden the metal film present on the inside surface due to implementation of the metal-plating sub-step.
13. A method according to one of the preceding claims, wherein the lining (8) is made of a metal selected from the following group: silver, gold, copper, nickel, platinum, and zinc.
14. A method according to one of the preceding claims, wherein the cavity (3) forms a throat (6) defining an opening (7) making it possible to put the cavity (3) into communication with the outside.
15. A method according to one of the preceding claims, which is designed so that the lining (8) forms the most superficial layer of the inside surface (2) that is designed to be in contact with the substance contained in said cavity (3).
16. A hollow body (1) provided with a glass inside surface (2) defining a cavity (3), said body (1) constituting a container (4), at least a fraction of said inside surface (2) being covered with a metal lining (8), characterized in that said hollow body comprises a single piece of glass inside which said cavity (3) is formed and constituting a container (4) designed for containing in the cavity (3) a cosmetics substance formed by an alcoholic liquid such as a body perfume, said container (4) being designed to be closed by means of a closure member (5), the inside surface (2) being covered with the lining (8) in a quantity per unit area that is equal to or greater than 1000 mg/m².
17. A body (1) according to the preceding claim, wherein the lining (8) is mostly made of a metal selected from the following group: silver, gold, copper, nickel, platinum, and zinc.
18. A body (1) according to one of claims 16 and 17, wherein that said lining (8) covers said inside surface (2) in a mass per unit area equal to or greater than 1500 mg/m², and preferably equal to or greater than 2000 mg/m².
19. A body (1) according to one of claims 16 to 18, wherein the wall (1A) of the hollow body (1) has an inside face corresponding to the inside surface (2) on which the lining (8) is deposited, and also has an opposite outside face (11) on which a marking (12) is placed, which is thus separated from the lining (8) by the thickness (E₂) of the wall (1A) defining the cavity (3).
20. A body (1) according to one of claims 16 to 19, characterized in that it comprises activation and grafting agents, e.g. tin and palladium, which form a fastening interface between the glass inside surface (2) and the metal lining (8).
21. A body (1) according to one of claims 16 to 20, wherein said cavity (3) forms a throat (6) defining an opening (7) making it possible to put the cavity (3) into communication with the outside, said opening (7) being designed to co-operate with said closure member (5) so as to close said container (4), which constitutes a bottle designed to store and to dispense a liquid body perfume.
22. A body (1) according to one of claims 16 to 21, characterized in that the lining (8) forms the most superficial layer of the inside surface (2) that is designed to be in contact with the substance contained in said cavity (3).

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