EP3867158A1

EP3867158A1 - Process for making a compostable infusion pod and compostable pod thus obtained

Info

Publication number: EP3867158A1
Application number: EP19797366.2A
Authority: EP
Inventors: Elisabeth Marie-France DA COSTA
Original assignee: Ssc Swiss Sustainable Coffee Sa
Current assignee: Ssc Swiss Sustainable Coffee Sa
Priority date: 2018-10-19
Filing date: 2019-10-18
Publication date: 2021-08-25
Also published as: IT201800009622A1; WO2020079653A1; WO2020079623A1

Abstract

The invention relates to a process for making a compostable pod comprising the following steps: • hot drawing the compostable film up to obtaining two or more recesses on the film; • introducing the infusion material in predetermined quantities; • selecting a first recess and a second recess and coupling them with each other; cold welding the first and second recess; cutting the edge of the recesses.

Description

PROCESS FOR MAKING A COMPOSTABLE INFUSION POD AND COMPOSTABLE POD THUS OBTAINED

The present invention falls within the field of compostable infusion pods. More specifically, it relates to a compostable pod made due to the use of an improved process for processing a compostable film and to the possible insertion of a related support structure.

There are compostable pods on the market, formed by two mutually thermo-sealed layers, between which the coffee or other infusion product is positioned.

However, such pods have the drawback of being little resistant to perforation and/or tears.

For this reason, there is a need to use rather thick layers, with firstly result in an obvious waste of material; additionally, such layers do not always lend themselves to being easily processed given that the increased thickness causes a variation of features - such as rigidity, resistance to traction and/or compression - and may induce even residual stresses as a consequence of dimensional variations.

Another highly significant problem relates to the increased permeability of the compostable pods to gases, and in particular to oxygen; the air, and the oxygen therein in particular, generates an alteration of the physical and organoleptic properties of the infusion product contained in the pod, which may also be such as to finally make it unusable.

For this reason, it is common practice in the industry of the field to enclose and sell such pods in small plastic single-dose packages.

Such operation certainly makes the pod production process less suitable and affordable, both in terms of time and costs; moreover, by doing this, also the low environmental impact that a compostable pod intrinsically has is altered, partly nullifying the goal of the product as conceived.

Therefore, the need remains to obtain compostable infusion pods that are resistant to tears and to accidental perforation, which may simultaneously ensure a sufficient level of resistance to the crossing by a gas, especially oxygen, but which remain easy to process by means of the currently known machinery and processes.

The object of the present invention therefore is to obviate the above- mentioned drawbacks and in particular, to make a compostable infusion pod using materials that can be adapted and used to make compostable pods by means of standard machinery already on the market. It is a further object of the invention to make a compostable infusion pod that is resistant to tears and to accidental perforations during the steps of making and/or storing and transport.

It is another object of the invention to make a compostable pod which is both resistant to the exposure to and penetration by a gas and which has walls of such thickness as to protect the product therein contained from the deteriorating action of the oxygen and of other gases; thus, the use is avoided of additional packaging required to preserve the goodness of the product therein contained.

It is a further object of the present invention to make compostable pods capable of containing infusion products also of a very different nature, such as e.g. coffee powder, herb teas and infusions in general, but also powder broth.

These and other objects are achieved by a process for making a compostable infusion pod according to appended claim 1 , and a compostable pod according to appended claim 8; other detail features of the process are indicated in the dependent claims.

Therefore, the subject matter of the present invention is a process for making a compostable pod containing infusion material, comprising the following steps:

• providing a compostable film obtained from the coupling of a first PLA layer with a second corn starch layer, in a grammage comprised between 80 g and 150 g, preferably between 98 g and 130 g;

• hot drawing the compostable film up to obtaining two or more recesses on the film so that the first layer is facing toward the inside of the recess and the second layer is facing toward the outside of the recess;

• introducing the infusion material in predetermined quantities into one or more of the two or more recesses so as to have at least a first recess provided with infusion material therein and at least a second recess free from infusion material therein;

• selecting a first recess and a second recess and coupling them with each other;

• welding the first and second recess;

• cutting the edge of the recesses along an abutment up to obtaining a compostable infusion pod.

This advantageously allows obtaining a compostable pod with satisfactory performance based on the parameters illustrated in the following. Furthermore, the process according to the invention may provide a step of dispensing an edible vaporised liquid over the first layer of the compostable film, after the step of providing compostable film and prior to the drawing step.

In this manner, the plasticity and elasticity of the film advantageously is improved.

In detail, the process of the invention moreover may provide a die-cutting step, possibly after the step of dispensing an edible vaporised liquid and in any case prior to the drawing step; this advantageously increases the capacity of the compostable film to undergo deformations without inducing undesired breaks or tears.

Moreover, a step of pressing the infusion material may be included, after the step of introducing the infusion material in predetermined quantities into one or more of the two or more recesses, and prior to the step of selecting a first recess and a second recess and coupling them to each other.

This becomes highly advantageous in the case in which the preselected infusion material is a mixture of coffee powders or the like, which subjected to pressure, are capable of giving the pod such structure as to allow the use thereof in machines for dispensing infused beverages without losing efficiency or material.

Alternatively, again according to the invention, the process may provide a step of inserting a structural element into one or more of the two or more recesses, after the step of hot drawing the compostable film and prior to the step of introducing the infusion material in predetermined quantities into one or more of the two or more recesses.

Indeed in this manner, the same type of materials and production steps may also advantageously be applied to making compostable pods in which the preselected infusion material is based on a mixture of leaves and/or flowers for tea or in any case for infusion, which when subjected to pressure, would not be capable of giving the pod the required structure. The presence of the structural element instead compensates for this absence, in any case maintaining the possibility of using the pod also in the machines for dispensing infused beverages without losing efficiency or material.

Additionally, the process according to the invention may include a step of drying the compostable film, after the step of hot drawing the compostable film and prior to the step of introducing the infusion material in predetermined quantities into one or more of the two or more recesses. This advantageously allows removing any traces of moisture or liquids which could then be enclosed inside the pods together with the infusion product, risking to ruin it or in any case alter the properties thereof.

Moreover, the step of welding the first and the second recess preferably may occur cold, for example by means of ultrasound, or hot, in a conventional manner; the preference for one or the other method advantageously allows limiting the risks of damaging the contents of the pod or the pod itself with the heat generated by the welding tools.

A further subject matter of the invention is a compostable infusion pod, characterised in that it is made by means of a process of the type described above.

Further objects and advantages of the present invention are more apparent from the following description concerning a preferred, but non limiting, example embodiment of the process for making a compostable infusion pod and of the compostable pod according to the present invention.

The compostable film preselected to make this first embodiment of a compostable infusion pod of the invention advantageously is made by company Ahlstrom Munkjo and is obtained by coupling two different films: a PLA-based film for the inner part of the pod and a corn starch-based parchment for the outer part of the pod.

Such specific material may currently be used to make closing membranes for cup-like infusion capsules, for example made of plastic or aluminium, albeit with flat, not drawn, geometry and with thicknesses that did not allow obtaining a sufficiently low permeability to the air; the method the subject matter of the invention instead is able to also process films with increased thicknesses with excellent results.

A second embodiment of the invention provides the use of a compostable film made by company Jura-tech.

PLA (polylactic acid or polylactide) is a polymer derived from corn, wheat or beetroot enriched with natural sugars (dextrose).

These sugars are converted into lactic acid by means of a fermentation process and therefore may be used to produce different types of resins. Parchment is made from corn starch and other natural raw materials. The peculiarity of the latter is the resistance thereof to weathering agents: indeed by immersing the parchment into a special edible liquid mixture, it acquires a barrier at the molecular level which protects it from oxygen.

This procedure implies that the parchment takes on mechanical features that are not very elastic.

By coupling the two materials, a single film with a barrier effect is obtained, provided with particular features and that is, resistance both to mechanical pressure and to temperature and a significant degree of elasticity.

Various tests were performed on films with different grammages and thicknesses starting from the creation of a compostable pod using the compostable Ahlstrom film, to verify the features of the material.

Initially a 98 g (intended as weight per square metre) non-barrier film was used, that is not resistant to oxygen: such film allows the oxygen molecules to penetrate the pod, accordingly modifying and altering the organoleptic qualities of the coffee.

The material was modelled using a hot thermoforming machine.

The film responded in optimal manner on low cycle times, but some breaks on the outer part of the film were detected using higher speeds.

The breaking problem was resolved by moistening the film prior to thermo deforming it, also using higher processing speeds.

This provided further data which allowed developing the final processing process.

Other tests with different grammage and thickness were performed using the same technique, and that is by moistening the film and making modifications concerning the temperature of the forming machine, in this case 130, but having a barrier.

The term “having a barrier” means a film that does not give rise to transfers of material toward the food - coffee in this case - by means of migration and/or transfer, infiltrations and naturally oxidation due to contact with air (which contains oxygen).

The results were positive and the material responded in an optimal manner.

The table below shows the tests performed with different types of compostable paper.

• The step with PLA is not present.

• The paper is always moistened prior to the test, with the exception of no. 8

Table with tests performed with moistened film:

The tests show that the film drawing only occurs if it is moistened beforehand. Accordingly, the machine was equipped with a vapour nebuliser which applies distilled water in the inner part of the compostable film. The film is then thermoformed by a hot deep drawing press with temperature variation.

The water indeed creates a thin protective layer which allows the drawing buffer not to crystallise - and therefore not to break - the film given that the drawing speed is such as to only act on the moist layer and not on the film itself.

Therefore, the film maintains - without altering - its elastic features, thus allowing it to be drawn without any problems.

At this point, the infusion product, in particular coffee, is positioned in the recesses made in the previous operation; by doing this, the capacity of the resistance of the pod to stresses advantageously is improved, especially during the step of running the hot water through it.

The use is provided of a support device or structure to be incorporated with the pod itself for products whose consistency and/or granulometry does not allow avoiding the pod containing it from deforming or interfering with the water dispensing during the infusion.

For the actual manufacturing of the pod, it is performed by coupling an upper sheet and a lower sheet of film already consisting of the two above- described materials coupled to each other.

Operatively, the sheets are stored in the form of sealed rolls that are removed from their casing when they are to be processed and that preferably remain exposed to air for the minimum time necessary.

The rolls of lower sheet and upper sheet are installed on plant supports and then partially unrolled in order to attach the free end of each sheet to an unwinder roller.

Downstream of the unwinder roller, the plant may provide a series of further rollers which act as bellows for controlling the tension of the sheets. A step of heating water in a boiler is provided at this point, by conveying the water vapour obtained toward a system of one or more nozzles that moisten the compostable material sheet to increase the processability thereof.

In particular, each nozzle may be provided with a flow adjustment knob or other technically equivalent device to allow modifying the possible quantity of vapour with which the sheet is sprayed, according to needs or the project features.

Then the process provides a step of die cutting the sheet, and it specifically provides making partial cuts at regular intervals along separation lines between the portions of sheet corresponding to each pod, both in the direction of the width and of the length of the sheet, thereby outlining rough squares on the sheet; this advantageously allows the sheet to accommodate the deformations and small movements caused by the successive drawing operation, avoiding to cause accidental rips or tears which would make the membrane unusable.

As mentioned, the drawing is provided after the die-cutting operation, which drawing is carried out by means of matched moulds; the station accommodating the sheets to be deformed may comprise - in a preferred embodiment - a system of suction mouths which limit the movements of the sheets themselves in order to increase the processing accuracy and decrease waste.

The sheet drying may occur, following the drawing and preferably only in the plant section dedicated to processing the lower sheet, in order to eliminate possible liquid residues which could ruin the infusion product or sheet itself.

Such drying operation may be completed for example, by means of hot air jets or other adequate means for the purpose.

This operation is not required for the upper sheet because the different exposure of the sheet itself to air and/or the generation of heat by the different adjacent machines allow an easier drying of the surface thereof. The lower sheet is arranged on a chain conveyor belt at the outlet of the drying station, the belt comprising metal links consecutively connected to one another; a plurality of cavities, or recesses, are obtained on each link, each cavity or recess intended to house a respective portion of drawn sheet.

Such chain conveyor receives and accompanies the lower drawn sheet for several metres toward the subsequent stations; immediately after the possible drying, the sheet is direct toward the filling station where a predetermined quantity of infusion product is deposited in the cavity created on the sheet during the drawing operation.

If the infusion product placed in the recesses has such features as to require it, a structural element is inserted in one or more of such recesses prior to the filling.

The filling station is followed by a cleaning station, in which possible product residues deposited on the sheet outside the recesses are removed.

After undergoing substantially the same processing, except the drying one, the upper sheet now meets the lower sheet transported by the belt into the coupling station; as with the drawing station, here too there may be provided suction systems for keeping the sheets in such position as to near and approach them to one another, without problems of accidental movements.

After the approaching, the sheets are brought by the belt to a first cold, or tack, welding station, which makes a plurality of joining points to join the upper sheet with the lower one.

Then, the pre-coupled sheets reach a second welding station, a hot station this time, where heated or in any case thermo-controlled mouldings come into contact with the sheets and melt them at an area which generally takes on a circular shape, thus isolating the infusion product in the pods. The chain conveyor stops accompanying the sheets now containing the sealed pods at the outlet of the hot welding station and a roller directs them toward a third ultrasound station; one or more grippers or mechanical hands are positioned laterally along the space between the second and third welding station, close to the edges of the sheets, with the purpose of moving the sheets in the short path between the two stations in which there is no conveyor belt.

The third welding station has elements that transmit the vibration to the piece to be welded, that is sonotrodes, positioned here in two parallel rows.

The hot and cold welding processes may both occur on the same capsules, or one or the other may be carried out according to needs.

The last operation that the sheets may undergo is die cutting again, which separates the actual pods from the waste, that is from the portions of coupled sheets surrounding the pods.

Finally, the pods fall onto a further belt that transports them toward possible subsequent sorting and/or packaging operations. WELDING PROCESS

As mentioned, two different welding strategies were assessed: a hot one and one using ultrasound.

The first actual welding used is the hot one, and that is by means of a mechanical welding apparatus that uses an electrical resistance therein that may be regulated by means of a temperature probe indicating the reading in degrees thereof. Such process generates these results:

• Rigidity of the outer crown

• Crystallisation of the material

• Weakening of the product structure

• Poor watertight integrity

• Alteration of the mechanical features of the film

The second and certainly safest one is the ultrasound one: it was possible to carry out different welding using two ultrasound generators (Telsonic 20 kHz and Herrmann 30 kHz) with a component at the end in this case called a bell sonotrode.

Ultrasounds weld without overheating the product and the fusion of the welded materials occurs at a molecular level.

Such process generates these results:

• Elasticity features of the film are not altered

• Outer crown is not crystallised because cold welding is used

• Excellent watertight integrity

• Processing process is speeded up

TESTS AND ANALYSES ON TEA AND COFFEE PRODUCTS

Tests were performed both on coffee and on tea.

A mechanical press in line with the pod manufacturing plant was used for the coffee, which forms the pod directly in the half drawing made beforehand in the film, while complying with the specific measurements for compatibility with specific infusion machines of different manufacturers. Indeed, after being drawn, a half-shell of compostable film is obtained, which passes under a cochlea dosing device, which causes the right dose of coffee to descend: between 6.2 and 6.5 grams. Then the half-shell passes under the mechanical press unit which, by means of a forming cylinder, forms the pod and at the same time sucks any coffee residues on the outer film of the pod to advantageously ensure the ultrasound welding is effective and does not have any coffee residues.

For tea, the process instead further requires a particular insert made of propylene and/or compostable material.

This insert is housed in the half-shell of a compostable film and then is filled with the approximate dose of tea for each mixture used. At this point, the filled half-shell does not require any pressing. After filling with the established quantity, the filled half-shell is coupled to the other half-shell obtained by drawing another portion of film and finally they are sealed to each other.

Various rings with different features were used and approved:

• Simple propylene ring without inner groove

• Simple propylene ring with inner groove

• Processed propylene ring

• Processed PLA ring

These solutions allow introducing quantities of infusion material both for single doses (from 1.2 to 2 g), for example for dispensing about 120 ml of tea, and for dual-dose pods, for example for dispensing about 240 ml of tea, and therefore housing up to 4.5 g of ground product in the ring.

FINAL CONCLUSIONS

In conclusion, to obtain a compostable pod, for example that is compatible with a machine of the type of those known under the trade name Nespresso Professional, there is a need to carry out the following process: For coffee:

• Draw the Ahlstrom compostable film (from 80 g to 150 g, preferably from 98 g to 130 g) using the above-indicated drawing process in order to obtain film half-shells

• Dose the coffee using a cochlea dosing device (from 6.2 g to 6.6 g)

• Form the coffee pod using a press, preferably in line

• Couple two half-shells of drawn film

• Cold seal with the aid of the 20 or 30 kHz sonotrode

• Block cut to obtain the finished product

For tea:

• Draw the Ahlstrom compostable film (98 g, 130 g) using the drawing process provided

• Insert the ring using a side pick and place

• Dose the tea based on the features required • Couple the other half-drawing

• Cold seal with the aid of the 20 or 30 kHz sonotrode

• Block cut to obtain the finished product

Thus, the advantages of the process for making a compostable infusion pod of the present invention have been observed.

The features of the compostable infusion pod that is also the subject matter of the present invention, are apparent from the description provided, as are the resulting advantages.

Finally, it is apparent that several other variants may be made to the process and to the pod at hand without departing from the inherent principles of novelty of the inventive idea, as is apparent that any materials, shapes and sizes of the details illustrated may be used as needed in the practical actuation of the invention, and they may be replaced with other equivalent ones.

Claims

1. A process for making a compostable pod containing infusion material, comprising the following steps:

• providing a compostable film obtained from the coupling of a first PLA layer with a second corn starch layer, in a grammage comprised between 98 g and 130 g;

• introducing the infusion material in predetermined quantities into one or more of the two or more recesses so as to have at least a first recess provided with infusion material therein and at least a second recess;

• welding the first and second recess;

2. The process for making a compostable pod according to claim 1 , characterised in that a step is provided, prior to the drawing step, for dispensing an edible vaporised liquid over the first layer of the compostable film.

3. The process for making a compostable pod according to claim 2, characterised in that a step is provided, prior to the drawing step, for die cutting the compostable film.

4. The process for making a compostable pod according to one of the preceding claims, characterised in that a step of pressing the infusion material is provided after the step of introducing the infusion material in predetermined quantities into one or more of the two or more recesses, and prior to the step of selecting a first recess and a second recess and coupling them to each other.

5. The process for making a compostable pod according to one of claims 1 to 3, characterised in that a step of introducing a structural element into one or more of the two or more recesses is provided prior to the step of selecting a first recess and a second recess and coupling them to each other.

6. The process for making a compostable pod according to one of the preceding claims, characterised in that a step of drying the compostable film is provided prior to the step of introducing infusion material in predetermined quantities into one or more of the two or more recesses.

7. The process for making a compostable pod according to one of the preceding claims, characterised in that the step of welding the first and second recess may occur by means of hot and/or cold welding.

8. A compostable infusion pod, characterised in that it is made by means of the process according to one of claims 1 to 7.