MXPA06003440A - Process for drying and cross-linking films of polymer bottles for carbonated beverages and equipment related thereto. - Google Patents

Abstract

The present invention is related to the industry for manufacturing bottles for beverages in general, mainly to carbonated beverages. The invention is more particularly related to the manufacture of novel plastic polymer bottles, which comprise a gas impermeable film. The advantages of the processes of the present invention over state-of-the art processes are that the present process generates a gas-impermeable film having a homogeneous thickness lengthwise and widthwise, the heat energy fed during the process being also effectively used. The inventive processes are characterised in that they comprise two stages: 1) introducing an air stream into the bottles at a temperature of from about 50 degree C to about 790 degree C, and at a speed of from about 1.5 m/s to about 2.5 m/s, the bottles being fixed by the neck thereof; 2) flowing a hotter air stream; the end of the first stage is determined when an amount of from about 75% to about 95% and preferably from about 85% to about 92% of the solvent pres ent in the film at the beginning of the process has been removed.

Description

PROCESS OF DRYING AND RETICULATING THE COATING OF BOTTLES OF POLYMERS FOR CARBONATED DRINKS AND RELATED TEAM FIELD OF THE INVENTION The present invention relates to the industry of the manufacture of bottles for beverages in general and carbonated beverages in particular. More specifically, it is related to the manufacture of new plastic polymer bottles that comprise a coating of gas-impermeable material.

ANTECEDENTS OF THE INVENTION For some time now, bottles of different polymers have been developed to replace traditional glass bottles for the bottling of beverages of all kinds. These bottles of polymeric material have had many advantages with respect to glass bottles, for example their production has been quite economical, and have therefore been able to be non-returnable bottles with the reduction of costs in terms of cleaning them. In addition to being economical, the bottles of these materials have allowed the generation of endless forms to particularize their use by Some specific company that may even have the exclusive use of certain models. On the other hand, it has cut with the unfair practices, which some companies have had, of buying empty containers in commercial establishments to destroy them and increase the production costs of the replacements that competing companies had to do. Despite all these advantages of plastic bottles, a disadvantage that has been presented, has been the porosity that these materials have, porosity that although they make it impermeable to liquids, they do not make them impermeable to gases and the entry of the external gases existing in the environment, of which the most harmful to the conservation of beverages would be oxygen, and the release of carbon dioxide from carbonated beverages, thereby modifying the organoleptic characteristics of the bottled beverage . There are several solutions to these drawbacks, but they cause problems that have not yet been solved. One solution that has been tested is the thickening of the container wall and although it resolves the gas permeability, it causes an increase in the production costs of the container and some molding problems. Other examples of solutions of the state of the art, that of application of a layer of material impervious to gases, have been disclosed in the patents US 5,658,619 and PCT / EP 00/10540, however they are not complete solutions since they are They create some inconveniences when applying them. Many of these drawbacks have to do with problems in the drying process of the applied waterproof layer, which consists of two processes, the solvent removal of the material and the other is the curing or reticulation of the resin. During drying you must work with temperatures and times. At low temperatures, the drying time is increased and coating run-off may occur, or even the homogeneity of the coating thickness may be modified, and at high temperatures, this temperature may affect the package itself.

OBJECTIVES OF THE INVENTION One of the objectives is to achieve the formation of a gas-impermeable plastic film in plastic bottles for carbonated drinks and not, with suitable characteristics of said film. Another object of the invention is to make possible the process and equipment required for the drying and crosslinking of a coating film in plastic bottles, so that the coating is of homogeneous thickness in width and length. Still another objective of the present invention is to achieve a process with the characteristics set forth in the first two objectives, where the heat energy that is needed to feed the process is also optimally utilized. Other objects and advantages of the present invention may be apparent from the study of the following description and the accompanying drawings for illustrative purposes only and not limitation.

DESCRIPTION OF THE INVENTION In a few words, the present invention consists in the process and equipment for the treatment of a gas impermeable layer made in bottles of polymeric plastic material.

Regarding the aspect of the process of the present invention, we will say that the process with the teachings of the present invention is applied to the treatment of a film formed by any method in the bottles. Said film, even before the application of the teachings of the present invention, is in a semi-liquid state, with a high solvent content. As a first step, a stream of air is circulated at a temperature between 50 and 70 ° C, with a speed of between 1.5 and 2.5 m / s, between the bottles hanging from the neck, by means of hanging from the state of the technique. In addition to these parameters (temperature and air speed), in this step you must control the amount of air that is fed to circulate between the bottles with the film to be dried and the time that the bottle is in contact with the current of In addition to achieving that the temperature of the bottle in contact with the hot air does not exceed 65 ° C, the next step must be taken when 75 to 95% of the solvent has been removed, and in the preferred mode of 85 and 92%. The next step in the process is to circulate a stream of air at a temperature between 60 and 80 ° C at a speed of between 1.5 and 2.5 m / s, making sure that the temperature of the bottle does not exceed 65 ° C. In this second step you should also control the amount of air which is fed to make it circulate between the bottles with the film to be dried and the time the bottle is in contact with the air stream, in addition to ensuring that the temperature of the bottle in contact with the hot air does not exceed 65 ° C The duration of this step is until the amount of solvent has completely evaporated and the deposited film is cured. To improve the exchange of mass and energy, the bottles must be in a transversal position to the air flow, that is, while the air flows from bottom to top, the bottles are horizontal. In addition, the bottles being hung from the free end of the neck are rotationally rotated at a speed of between 100 and 300 RPM, so as to homogenize the incidence of air on the surface of the bottle. As regards the aspect of the invention related to the equipment, the description will be made according to the modalities illustrated and described below.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows a vertical section of the first incorporation of the equipment. Figure 2 shows a vertical section of the second embodiment of the equipment.

DETAILED DESCRIPTION OF THE INVENTION The invention in its broadest concept is reflected in two aspects: a process of treatment of a film applied by any method to the external surface of the bottles, in order to confer them characteristics of impermeability to the gases and in an equipment that allows the application of the process. This treatment is characterized by two stages of air incidence in the film applied on the external surface of the bottle. In a first stage, air is impinged at a temperature between 50 and 70 ° C at a flow rate of 2.5 m / s. This stage must respect, throughout the duration of the same, the fact that the temperature of the container must be less than or equal to 65 ° C. The completion of the stage occurs at the time when 75 to 95% , and ideally 85 to 92%, of the solvent present in the film has been eliminated. In order to achieve these parameters and levels, the mass volume of air to be circulated between the spaces left in the bottles must also be controlled, this space also being a parameter to be controlled. The condition of not allowing the bottle to acquire a temperature higher than 65 ° C is to avoid the deformation of the bottle and the crystallization of the resin. The second stage of the treatment is the application of an air current at a temperature between 60 and 80 ° C at a speed of between 1.5 and 2.5 m / s, which is the same air velocity in the first stage . The duration of this stage is determined by the mass air expenditure with the temperature and speed already indicated above and the amount of solvent to be dragged. In any case, the stage will be considered finished when there is no solvent residue in the film applied in the container. The air used at the beginning of the second stage is the same air that results from the application of the first stage and the air used at the beginning of the first stage is a part of the air that results from the application of the second stage and a part main environmental air. Between the first and the second stage, an air heating is provided through heating means. These heating means, in a preferred embodiment, consist of half-wave infrared lamps. The time that the bottles with the coating remain in front of the half-wave infrared lamps is between 15 and 30 seconds, and in another preferred mode, 25 seconds. As for the equipment slope, it is shown in the figure the basic cell of the plant according to the invention. It consists of a camera (1) delimited by walls (8, 15, 17 and 18), composed of the following elements: i. A first lower area (2) for treating the bottles (4), and a second upper area (5) for treating the bottles; ii. An oven (2 ') placed in the lower area (2) equipped with heating elements (3) (for example, infrared lamps) suitable for the emission of thermal radiation; this furnace is delimited by a wall (14), part of the outer wall (17), an upper wall (10), and a lower wall (11) - the two appropriate for thermal radiation reflection and for allow the gas flow to pass through them; iii. Known means (not shown in the figures) suitable for the creation of the ambient air stream (6) and for controlling the flow rate of the flow; iv. A chamber (12) suitable for receiving said air stream (6); this chamber is delimited by walls (8, 15) and by a door (7) communicating with a vertical duct (19), which is delimited by a wall (8) and an element (9) which in turn communicates with said lower area (2); v. A chain with many clips (13) that hold and hold the bottles; the so-called mandrels, in the oven (2 '); said chain passes outside the furnace parallel to a wall (14) equipped with a suitable opening to facilitate the passage of the neck of the bottles, thus making it possible to keep the neck of the bottles out of the oven (2 ') and divide the air flow (6) During the process, the bottles (4) enter the furnace (2 ') near the lamps in a specific position (position 4"), move through the whole furnace in said position, exit the furnace, rise, and place in the furnace. a specific position (4"'). Meanwhile, an air stream (6), which is created and controlled by apparatuses not shown in the figure, flows from the chamber (12) to the lower area (2) through a conduit (19). Once the air current arrives at said area, it is divided by a wall (14) in two parts; a first air stream enters through the wall (11) to enter the oven (2 '), control the temperature of the bottles, and cool the apparatus that emits the thermal radiation or heating elements (3); a second stream of air flows upwards to exit the furnace (2 ') by rubbing a wall (14) to keep the collars of the bottles (4) held in the mandrels (13) cold. The first part of the air stream, after the heating elements (3) have cooled, passes through a wall (10) and flows upwards to the top of the chamber (1) where it rubs against the bottles in position 4 '", thus finishing the drying process of the paint, and then flowing to the exhaust chamber 16. In this chamber, the hot air stream is at least partially sent to the chamber 12 to through a door (7) in order to regenerate heat and keep the oven temperature constant (2 '). If there is not enough space along to handle the required output, the two segments of the plant can be placed side by side instead of in an on-line distribution (see Figure 2 where all the parts have exactly the same numbering as in Figure 1). In this version of the invention, the bottles follow the following route (see drawing): starting from the right side, the bottles enter the chamber (1) in position 4", travel through the oven (2 ') towards the observer, rotate to the left to enter oven 2 'a on the left side of the plant, away from the observer; now, they go up in position 4"'a, they travel through the upper area (5a) of the left side of the plant heading towards the observer again, they turn to the right, and finally they enter position 4'" in Part 5 through which they pass, away from the observer, towards the exit of the drying plant. The invention has been described sufficiently so that a person with average skill in the art can reproduce and obtain the results mentioned in the present invention. However, any skilled person in the field of the technique that is the subject of the present invention may be able to make modifications not described in the present application, however, if for the application of these modifications in a particular process, the matter claimed in the following is required claims, said structures should be understood within the scope of the invention.

Claims (8)

CLAIMS Having sufficiently described the invention, it is considered as a novelty and therefore it is claimed as property what is expressed and contained in the following claim clauses.

1. Drying and crosslinking process of the coating of polymer bottles for carbonated drinks, characterized in that it comprises two stages, one of which consists in causing an air current at the temperature of between 50 and 70 ° C to impinge on the bottles, with a speed between 1.5 and 2.5 m / s, with the fixed bottles of the neck; the other stage consists in influencing the bottles with an air current at a temperature between 60 and 80 ° C, with a speed of between 1.5 and 2.5 m; the end of the first stage is established when the film has removed 75 to 95%, and ideally 85 to 92%, of the solvent present in the film at the beginning of the process and the end of the second stage is established when has eliminated the total solvent.

2. Drying and crosslinking process of the coating of polymer bottles for carbonated drinks, as claimed in the previous claim, characterized in that the temperature of the container is controlled with the film so that this temperature is when more than 65 ° C.

3. Drying and crosslinking process of the coating of polymer bottles for carbonated drinks, as claimed in claim 1 or 2, characterized in that in addition, because the air used at the beginning of the second stage is the air that was obtained at the end of the first stage, with a heating carried out by means of heating of the type of half-wave infrared lamps. and the air that is used at the beginning of the first stage has at least a part of the air that was taken out of the second stage, combined with the rest of the air from the environment.

4. Drying and crosslinking process of the coating of polymer bottles for carbonated drinks, as claimed in any of claims 1 to 3, characterized in that, in addition, by the fact that part of the air in the environment is circulated through the necks of the bottles to keep them at a lower temperature than the rest of them.

5. Drying and crosslinking process of the coating of polymer bottles for carbonated drinks, as claimed in any of claims 1 to 4, characterized in that in addition, the time that the bottles with the coating remain in front of the infrared lamps of average wave is between 15 and 30 seconds, and in another preferred mode 25 seconds.

6. An apparatus for treating the coating of bottles made of a thermoplastic material according to the process described in claim 1 consisting of a chamber (1), delimited by the walls (8, 15, 17, 18), consisting of the following elements : i. A first lower area (2) for treating bottles (4), and a second upper area (5) for treating bottles; ii. A homo (2 ') located within the lower area (2) equipped with heating elements (3) suitable for the emission of thermal radiation; this furnace is delimited by a wall (14), part of an exterior wall (17), an upper wall (10), and a lower wall (11) - the two suitable for the reflection of thermal radiation and the passage of gas through them; iii. Suitable means for creating the ambient air stream (6) and for controlling the flow rate of the air flow; iv. A chamber (12) suitable for receiving said air stream (6); delimited by walls (8, 15) and by a door (7) communicating with a vertical conduit (19), which is delimited by a wall (8) and an element (9) which in turn communicates with said area lower (2) to allow air flow from the chamber (12) to said area (2); v. A chain with a plurality of mandrels (13) that hold and hold the bottles inside the oven (2 ') when they are in the vicinity of the oven and when they are passing outside, parallel to the wall (14) that provide an opening adapted to allow the passage of the neck of the bottles, making it possible to keep the necks of the bottles out of the oven (2 ') and at the same time to divide the air flow (6).

7. An apparatus as claimed in claim 12 wherein the door (7) separates the inlet chamber (12) from the air of the outer chamber (16) from where the air, after passing from the lower area (2) to the upper area (5) and heated through the heating elements (3), flows out of the chamber; said door (7) being adapted to operate in such a way as to allow the passage of part of the hot air flowing out of the outlet chamber (16) towards the inlet chamber (12).

8. An apparatus as claimed in claim 12 wherein said wall (14) also serves to divert part of the air stream coming from the conduit (19) to the area (2) to send it to the mandrels (13) to cool the Necks of the bottles.