Machine for thermoforming and method for thermoforming

Abstract

A thermoforming machine and a thermoforming method are provided, in particular for producing capsules for obtaining beverages. The capsules (C) are produced from a film (F) of thermoformable material by thermoforming one or more predefined portions (X) of the film. The one or more predefined portions (X) of the film of thermoformable material are pre-heated, i.e. they are heated before being subjected to thermoforming so as to minimize the probability that the film of thermoformable material tears or breaks during thermoforming or after thermoforming.

Claims

1. A method for producing a capsule for obtaining beverages from a film of thermoformable material having a thermoforming temperature comprising the following steps: welding a predefined portion of the film to one rigid element; and additionally pre-heating the predefined portion of the film to a pre-heating temperature lower than the thermoforming temperature without any forming, by means of a first heating system, wherein the pre-heating temperature ranges from 50° C. to 80° C. and the thermoforming temperature ranges from 100° C. to 190° C., and afterwards; forming the heated predefined portion so as to form the capsule by thermoforming, wherein the thermoforming comprises a step of heating the predefined portion of the film to the thermoforming temperature by means of a second heating system and a step of forming the predefined portion into a different shape so as to obtain the capsule, wherein said second heating system is different from said first heating system, and wherein no further treatment steps are interposed on the predefined portion between said step of pre-heating and said step of forming by thermoforming, so that the predefined portion is subjected to a welding step and two heating steps.

2. The method according to claim 1, wherein a maximum temperature reached by the predefined portion following said step of pre-heating is in a range from 50% to 100% of the maximum temperature reached by the predefined portion during said step of formation of the capsule by thermoforming.

3. The method according to claim 1, wherein said step of pre-heating is such that the predefined portion of the film reaches a temperature which is higher than or equal to 50° C. and/or lower than or equal to 80° C.

4. The method according to claim 1, wherein said step of forming the heated predefined portion of the film comprises the following sub-steps: a first sub-step of partial thermoformation so as to obtain an object having a shape and/or a dimension which is different from the shape and/or dimension, respectively, of the capsule; and a second sub-step of final formation so as to obtain the capsule from the object.

5. The method according to claim 1, further comprising the following step: welding the film of thermoformable material to a rigid element.

6. The method according to claim 1, wherein the film of thermoformable material is made of material, selected from the group consisting of polylactic acid (PLA) based materials, cellulose and polylactic acid composites, PHA (Polyhydroxyalkanoates), amide compounds, PBS (Polybutylene succinate), PET (polyethylene terephthalate), PP (polypropylene) and PA (polyammide).

7. The method according to claim 4 wherein: said second sub-step of final formation is performed without supplying heat.

8. The method according to claim 1, wherein said step of pre-heating is carried out through infrared radiation or through one or more hot bars or by means of a blast of hot air.

9. The method according to claim 1, wherein: said step of pre-heating is performed after said step of welding and said step of pre-heating heats the predefined portion of the film to reach the pre-heating temperature lower than the thermoforming temperature without any forming, whereby the probability of the film breaking during and after thermoforming is minimized.

10. A method of forming a capsule from a film of thermoformable material having a thermoforming temperature comprising the steps of: welding a predefined portion of the film to one rigid element; and additionally after said step of welding, pre-heating a portion of the film of thermoformable material to a pre-heating temperature lower than the thermoforming temperature at a heating station without any forming, wherein the pre-heating temperature ranges from 50° C. to 80° C. and the thermoforming temperature ranges from 100° C. to 190° C.; moving the portion of the film of thermoformable material to a partial thermoforming station with no further treatment steps interposed before forming the portion; thermoforming the portion of the film of thermoformable material into a different shape at the thermoforming temperature, wherein the thermoforming temperature is higher than the pre-heating temperature; and forming the portion of the film of thermoformable material in the different shape into a final shape at a forming temperature less than the thermoforming temperature.

11. The method of forming a capsule from a film of thermoformable material as in claim 10 wherein: the pre-heating temperature is greater than one-half of the thermoforming temperature.

12. The method according to claim 10, wherein said step of pre-heating is carried out through infrared radiation or through one or more hot bars or by means of a blast of hot air.

13. A method of forming a capsule from a film of thermoformable material having a thermoforming temperature at a thermoforming station comprising the steps of: pre-heating a portion of the film of thermoformable material having the thermoforming temperature to a pre-heating temperature lower than the thermoforming temperature ranging from 50° C. to 80° C. without any forming; moving the portion of the film of thermoformable material to the thermoforming station; hot thermoforming the portion of the film of thermoformable material into a different shape at the thermoforming temperature ranging from 100° C. to 190° C.; and forming the portion of the film of thermoformable material in the different shape into a final shape by cold forming without supplying heat.

14. A method of forming a capsule from a film of thermoformable material at a thermoforming station as in claim 13 wherein: no forming of the portion of film of thermoformable material is interposed between said step of pre-heating and said step of hot thermoforming.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The present invention will be described with reference to the attached figures in which the same reference numerals and/or marks indicate the same parts and/or similar and/or corresponding parts of the system.

(2) FIG. 1 schematically shows a portion of a machine according to an embodiment of the present invention.

(3) FIG. 2 schematically shows the system of FIG. 1 during a step of the method according to an embodiment of the present invention.

(4) FIG. 3 schematically shows the system of FIG. 1 during a further step of the method according to an embodiment of the present invention.

(5) FIG. 4 schematically shows the system of FIG. 1 during a further step of the method according to an embodiment of the present invention.

(6) FIG. 5 schematically shows the system of FIG. 1 during a further step of the method according to an embodiment of the present invention.

(7) FIG. 6 schematically shows the system of FIG. 1 during a further step of the method according to an embodiment of the present invention.

(8) FIG. 7 schematically shows the system of FIG. 1 during a further step of the method according to an embodiment of the present invention.

DETAILED DESCRIPTION

(9) Hereinafter, the present invention is described with reference to particular embodiments, as illustrated in the attached figures. However, the present invention is not limited to the particular embodiments described in the following detailed description and represented in the figures, but rather the described embodiments simply exemplify the various aspects of the present invention, the purpose of which is defined by the claims. Further modifications and variations of the present invention will be clear to those skilled in the art.

(10) FIG. 1 schematically shows a portion of a machine M according to an embodiment of the present invention. The machine represented in the figures is of the drum type and thus comprises a drum T that is circular in shape around which the operative stations of the machine M are arranged. The arrow r indicates the direction of rotation of the drum T when the machine is operating. This is the forward direction of the machine. However, the present invention can also be implemented on linear machines, i.e. on machines that do not comprise a drum and in which the operative stations are aligned along a substantially planar direction. In this case, the forward direction will not be circular but linear.

(11) The drum T of the machine M comprises a plurality of housings each of which houses a rigid element A. An example of such a drum is described in European patent EP 2 152 589 B1 and in the relative PCT application published with number WO 2008/129350 A1.

(12) In the system shown in the figures the rigid elements A are containers adapted for containing the capsules that will be formed by thermoforming. However, based on the present invention, the rigid elements A could also be reinforcing elements, for example reinforcing rings adapted for reinforcing the capsules that will be formed by thermoforming. Through the present invention, it is indeed possible to obtain capsules for beverages provided with reinforcing rings like those described for example in document US 2011/0247975 A1.

(13) A film F of thermoformable material extracted for example from a reel not shown in the figures is slid over the surface of the drum T so as to cover the rigid elements A housed in the drum T. The film F can be made of biodegradable material or non-biodegradable material. The film F can for example be made of polylactic acid (PLA) based materials, composites of cellulose and polylactic acid, PHA (Polyhydroxyalkanoates), composites of amide and PBS (Polybutylene succinate). Moreover, the film F can be made of PET (polyethylene terephthalate), PP (polypropylene) or PA (polyammide).

(14) The figure also schematically shows the operative stations of the machine M the functions of which will be described in detail hereinafter with reference to the following figures. It is possible to see a welding station 101, a heating station 102, and a thermoforming station 103 comprising a partial thermoforming station 103a and a final forming station 103b.

(15) FIG. 2 schematically shows the welding step of a rigid element A to the film F of thermoformable material at the welding station 101 of the machine M. The welding station 101 can for example be configured to carry out welding by means of one or more hot bars or by ultrasound. Thanks to the welding, the film F of thermoformable material is fixed to a rigid element A, in particular to the rigid element A that is located at the welding station 101 of the machine M. In this way, a predefined portion X that will be subjected to thermoforming in order to obtain the desired capsule C, illustrated in FIGS. 6 and 7, is identified and defined on the film F of thermoformable material. In the case shown in FIG. 2 in which the rigid element A is a container adapted for containing the capsule C that will be formed by thermoforming, the predefined portion X is the portion of the film F arranged directly above the container or rigid element A after it has been welded to the film and thus enclosed by the perimeter of the upper edge of the container or rigid element A. In the case for example in which the rigid elements A are reinforcing rings, the predefined portion X is the portion of film F arranged inside the perimeter of each reinforcing ring after it is welded to the film F.

(16) FIG. 3 schematically shows the system during a subsequent step with respect to the one shown in FIG. 2.

(17) In the step shown in FIG. 3, the predefined portion X of the film of thermoformable material is subjected to heating at the heating station 102 of the machine M. The heating station 102 can for example be configured to carry out heating through infrared radiation (IR) or through one or more hot bars or by means of a blast of hot air or other suitable heating systems. The heating can be done in such a way that the portion X of the film F reaches a temperature greater than or equal to 50° C. and/or less than or equal to 80° C. The machine M can be advantageously provided with systems for detecting the temperature of the portion X at the heating station 102. Moreover, the machine M can be advantageously provided with systems for controlling the temperature configured so as to regulate the temperature of the portion X based on the detection of the temperature itself. The control means can for example interrupt the heating of the portion X when a predefined target temperature is reached. Moreover, the control means can also be configured to increase and/or decrease the intensity of the heat supplied to the system.

(18) FIG. 4 schematically shows the system during a subsequent step with respect to the one shown in FIG. 3.

(19) In the step shown in FIG. 4, the predefined portion X of the film of thermoformable material that has been preheated by the heating station 102 is subjected to hot thermoforming at the station 103a. The thermoforming can for example be such that, during the thermoforming, the portion X of the film of thermoformable material is heated to a temperature which is higher than or equal to 100° C. and/or lower than or equal to 190° C. Given that the portion X has been preheated at the heating station 102, the probability of the portion X tearing during this hot thermoforming step at the station 103a is substantially reduced. In the example shown in FIG. 4, the station 103a is a partial thermoforming station. In particular, the object P that is obtained at the station 103a through partial thermoforming does not yet have the final shape and/or size of the final capsule C that it is wished to produce. The object P has thus only been partially formed and is of a different shape and/or size with respect to the final capsule C that it is wished to produce. FIG. 5 schematically shows a possible result after the thermoforming procedure at the station 103a has been completed. In particular, FIG. 5 shows that the object P′ is obtained after the contraction of the object P during the cooling thereof at the end of the thermoforming. In particular, it has been observed that often, in the step immediately after thermoforming when the hot thermoforming mould is removed, the thermoformed and dilated material tends to contract after the cooling of the system and to thus produce a capsule with a smaller inner volume than the desired volume.

(20) In order to avoid this problem, as is schematically shown in FIG. 6, the object P′ that is contracted with respect to the object P obtained by partial thermoforming at the station 103a is subjected to a final forming step at the final forming station 103b so as to obtain the desired shape and/or Ia size of the capsule C that is wished to be produced. The final forming or shaping step can advantageously take place cold, i.e. without supplying heat. The forming or shaping from the object P′ to the capsule C is in this case carried out exclusively through pressure or force exerted at the final forming station 103b, for example by a suitable molder or mould.

(21) It should also be noted that it has also been observed that the tearing or breaking of the thermoformable material often takes place in the step shown schematically in FIG. 5 after the excessive thermal shock and the forming force. The preheating carried out at the station 102 upstream of the partial thermoforming station 103a substantially reduces the probability of the material tearing in the step shown in FIG. 5. The cold forming carried out at the station 103b does not generally have problems of tearing.

(22) As schematically shown in FIG. 7, when the moulder of the forming station 103b is withdrawn, the capsule C is obtained with the desired shape and size. In the case shown in the figure, the capsule C of thermoformable material is located inside the container of rigid material A.

(23) Although the present invention has been described with reference to the embodiments described above, it is clear to those skilled in the art that it is possible to make different modifications, variations and improvements of the present invention in light of the teaching described above and in the attached claims, without departing from the object and the scope of protection of the invention.

(24) For example, although in the figures shown the welding of the film F to the rigid elements is carried out before the thermoforming, according to alternative embodiments of the present invention, the welding can also take place after the thermoforming and the welding station can thus be arranged downstream of the thermoforming station or even in a second machine separate from the machine based on the present invention.

(25) Moreover, it is clear to those skilled in the art that although the various steps have been described in sequence, they can be carried out simultaneously on different portions of the film F so as to accelerate the production of the capsules C.

(26) Moreover, although a drum machine has been described, the invention can also be implemented in linear systems.

(27) The reinforcing elements are not limited to the impermeable containers shown in the figures but can be of various types, for example reinforcing rings.

(28) Moreover, although in the attached figures it is shown that the heating that precedes the thermoforming is carried out at a heating station arranged upstream of the thermoforming station, based on the method according to a particular embodiment of the present invention, the heating that precedes the thermoforming can be carried out directly at the thermoforming station. For example, in this case the heating can be carried out by blasting hot air directly at the thermoforming station. In other words, in this case, the portions of the film of thermoformable material are heated twice directly at the thermoforming station: a first heating is the heating that precedes the thermoforming and a second heating is the heating of the thermoforming itself.

(29) Finally, things that are deemed to be known by those skilled in the art have not been described in order to avoid needlessly obscuring the invention described.

(30) For example, the drum machine has not been described in detail in all of its aspects or functions. An example of such a machine can, however, be found for example in WO 2008/129350 A1.

(31) Moreover, further steps that can be carried out after the steps described in detail above have not been described in detail. For example, the capsule C can be cut from the film of thermoformable material F at a cutting station so as to separate the capsule from the film F. Moreover, the capsule can be filled with the desired product at a filling station. The filled capsule can then be sealed, for example with a film of impermeable material. These steps can be carried out in any order. Moreover, one or more of these steps can be carried out directly on the machine based on the present invention that will thus be equipped with the suitable operative station or on one or more further separate machines with respect to the machine according to the present invention. For example, a machine according to the present invention could make it possible to obtain the empty capsules C, welded or not to the rigid elements A. The empty capsules C could then be supplied to a second machine for filling with the desired product and subsequent sealing.

(32) Consequently, the invention is not limited to the embodiments described above, but is only limited by the scope of protection of the attached claims.