FR3120006A1 - METHOD FOR MANUFACTURING SECABLE PACKS - Google Patents

Abstract

PROCESS FOR MANUFACTURING SECABLE PACKS. A pack of products divisible into unitary products is made from an amorphous polymer material having a degree of crystallinity of less than 30%. A zone (401) where an incision is to be made (403) is heated so that the amorphous polymer material in this zone (401) undergoes local crystallization bringing the degree of crystallinity to at least 40% in the zone (401) where the incision (403) is to be made. In a pre-cutting operation, the incision is made (403) in the area (401) where the amorphous polymer material has undergone local crystallization. The incision makes the pack of products divisible into unitary products. Figure for abstract: Fig. 4

Description

METHOD FOR MANUFACTURING SECABLE PACKS

One aspect of the invention relates to a method for manufacturing a pack of divisible products into unitary products. This process can be used, for example, to make pots containing a semi-liquid substance such as, for example, yogurt or other semi-liquid foods. The invention can therefore be implemented in the dairy industry and the food industry. Other aspects of the invention relate to a machine for producing a pack of divisible products into unitary products and a pack of divisible products into individual products.

STATE OF THE PRIOR ART

Packs of yoghurt pots, which are divisible into unitary yoghurt pots, can be manufactured according to a technology designated “FFS”. FFS is an acronym for the English verbs “form”, “fill” and “seal”, which can be translated as “former”, “fill”, and “sceller”. FFS technology was designed for polystyrene, commonly referred to by the acronym PS. Indeed, polystyrene is a plastic material that is easy to shape, rigid, and easy to cut and pre-cut.

Yogurt pot packs are commonly made from polystyrene sheet using FFS technology as follows. The polystyrene sheet is heated to soften it and form pots using a mold. This operation is called “thermoforming”. The formed pots are then filled with yoghurt. The filled jars are sealed with a lid. At this stage the jars are still attached to each other by intermediate sections which are flush with the cover sealing the jars. Cuts and pre-cuts are applied in these polystyrene intermediate sections. The cuts are applied to form unit packs of yoghurt pots. The pre-cuts are applied to make the yoghurt packs divisible into unitary yoghurt pots.

An FFS machine therefore typically comprises a thermoforming station, a filling station, a sealing station and a cutting and pre-cutting station. The FFS machine manufactures continuously and in sequence successive packs of yoghurt pots from a polystyrene film in the form of a reel. In fact, from a manufacturing point of view, the polystyrene film is the equivalent of a long series of polystyrene sheets attached to each other. The sealing station of the FFS machine forms lids from a film of material suitable for sealing, also in reel form. The filling station is supplied with yogurt to be put into pots.

There is a need for a solution making it possible to manufacture packs of divisible products into unitary products which are relatively easily recyclable.

One aspect of the invention provides for a method of manufacturing a pack of divisible products into unitary products from an amorphous polymeric material having a degree of crystallinity of less than 30%, the method comprising:
- the heating of an area where an incision is to be made so that the amorphous polymer material in this area undergoes local crystallization bringing the degree of crystallinity to at least 40% in the area where the incision is to be made; and
- making an incision in the zone where the amorphous polymer material has undergone local crystallization, the incision making the pack of products divisible into unitary products.

Another aspect of the invention provides for a machine for manufacturing a pack of divisible products into unitary products, the machine being able to implement the method defined above.

Yet another aspect of the invention provides, in a pack of products divisible into unitary products, the pack of products comprising an amorphous polymer material, the pack of products comprising a part where the amorphous polymer material has a degree of crystallinity of at least 40% , the part comprising an incision making the pack of products divisible into unitary products.

Amorphous polymeric material having a degree of crystallinity less than 30% is generally difficult to cut and pre-cut. For this reason, such a material is generally not used to manufacture packs of divisible products into unitary products according to the FFS technology described above. The present invention provides a solution to this problem by applying local crystallization which makes the amorphous polymeric material easier to cut and pre-cut. In addition, the invention makes it possible to adapt relatively easily an existing FFS machine, designed for manufacture from a polystyrene film, in order to manufacture packs of products which can be split into unitary products from an amorphous polymer material with the machine thus adapted.

An amorphous polymeric material, such as polyethylene terephthalate, commonly referred to by the acronym PET, is more easily recyclable than polystyrene. In fact, polyethylene terephthalate already has a well-developed recycling channel and therefore constitutes an interesting candidate for the replacement of polystyrene. easily recyclable.

In one embodiment, the unit products are in the form of filled and sealed containers. The method defined in the foregoing comprises the thermoforming of the containers from the amorphous polymer. The heating of the area where the incision is to be made is at least partially carried out before the thermoforming of the containers.

In one embodiment, the heating of the zone where the incision is to be made is partially carried out upstream of the thermoforming of the containers and partially carried out downstream of the thermoforming of the containers.

In one embodiment, the amorphous polymeric material comprises at least one of the following materials: polyethylene terephthalate and polylactic acid.

In one embodiment, the area where an incision is to be made is heated to a temperature between 130°C and 180°C.

In one embodiment, the area where an incision is to be made is heated for a period of between 0.8 s and 6 s.

In one embodiment, the area where an incision is to be made has a thickness of between 0.30 mm and 2 mm.

In one embodiment, the method defined above comprises heating an area where a cut is to be made so that the amorphous polymer material in this area undergoes local crystallization bringing the degree of crystallinity to at least 40% in the area where the cut is to be made. The method further comprises making a cut in the area where the amorphous polymer material has undergone local crystallization, the cut allowing individual handling of the pack of divisible products.

The heating of the zone where the incision is to be made and the heating of the zone where the cut is to be made are carried out jointly by means of at least one local crystallization station.

For purposes of illustration, some embodiments of the invention are described in detail with reference to the accompanying drawings. This description will reveal additional characteristics to those mentioned in the foregoing, as well as the advantages that these additional characteristics can provide.

BRIEF DESCRIPTION OF THE DRAWINGS

The is a schematic diagram of a basic machine for manufacturing divisible product packs into unitary products.

The is a schematic top view of a multitude of pots on which a (pre-)cutting station of the machine will carry out cutting and pre-cutting operations.

The is a schematic diagram of an advanced machine for manufacturing packs of divisible products into unitary products.

The is a schematic top view of a multitude of pots, similar to the , in which zones of local crystallization are indicated.

The is a schematic top view of a heating plate of a first crystallization station in the advanced machine illustrated in .

The is a schematic top view of a hot plate of a second crystallization station in the advanced machine shown in .

The is a schematic top view of a pot support which complements the heating plate of the second crystallization station.

DESCRIPTION OF SOME EMBODIMENTS

The schematically illustrates a machine 100 for manufacturing packs of divisible products into unitary products. The machine 100 can be used, for example, to manufacture packs of pots containing a semi-liquid substance such as, for example, yogurt or other semi-liquid foods. By way of illustration, it is assumed in the following that machine 100 is used to manufacture packs of yoghurt pots. The machine 100 can be of the FFS type, FFS being an acronym of the expression in English “form, fill, and seal” which can be translated into French as “form, fill and seal”. In what follows, the machine will be referred to as “FFS 100 machine” for convenience.

The FFS machine 100 comprises heating stations 101, a forming station 102, a filling station 103, a sealing station 104, and a (pre)cutting station 105. A thermoformable film 106 in the form of a reel is coupled to an entry section of the FFS machine 100. The thermoformable film 106 can have a thickness between, for example, 0.5 mm and 2 mm. A sealing film 107, also in reel form, is coupled to the sealing station 104. The term lidding film could also have been used instead of the term sealing film 107.

Briefly, the FFS 100 machine works as follows. The FSS machine sequentially unwinds the reel of thermoformable film 106. The heating stations 101 then receive sequentially successive sections of the thermoformable film 106. A section of the thermoformable film 106 located in the heating stations 101 is softened by heating to a temperature between between about 100°C to 150°C. The section of the thermoformable film 106 thus softened is transferred to the forming station 102.

Forming station 102 thus receives successive softened sections of thermoformable film 106 sequentially. Forming station 102 presses a softened section of thermoformable film 106 into a mold. The forming station 102 thus forms a set of pots which are still attached to each other. The set of pots thus formed is also still attached to a set of downstream pots, previously formed, and to a softened section of the thermoformable film 106 upstream, which may be in the forming station 102. The set of pots freshly formed is transferred to the filling station 103.

The filling station 103 thus receives sequentially sets of pots still integral with each other. The filling station 103 fills the pots with yoghurt. Here again, the pots that have just been filled are attached to each other. These pots are also still secured to the downstream pots still to be filled, or being filled, and are also secured to the downstream pots which have been previously filled. Jars filled with yogurt are transferred to sealing station 104.

The sealing station 104 thus receives sequentially sets of pots filled with yoghurt. The sealing station 104 forms lids from a section of the sealing film 107 whose reel is also unwound sequentially. The sealing station 104 applies these lids to the pots filled with yoghurt in order to seal them. Thus, the sealing station 104 provides a set of filled and sealed pots which are still attached to each other. These filled and sealed pots are also still attached to the filled and sealed pots downstream, previously taken out of the sealing station 104, and to the pots filled with yoghurt upstream, which are still to be sealed or in the process of being sealed.

The (pre)cutting station 105 thus receives sequentially sets of filled and sealed pots. The (pre)cutting station 105 performs a cutting operation in order to separate a set of filled and sealed pots from the other filled and sealed pots which are upstream. The set of filled and sealed pots thus forms a pack 108. In addition, the (pre)cutting station 105 performs a precutting operation in order to make the pots of the pack divisible. The pre-cutting operation consists of making incisions in the intermediate sections connecting the pots of the pack to each other. These incisions typically have a depth between about 30% to 70% of the thickness of the intermediate sections.

The schematically illustrates a multitude of pots 200 on which the (pre)cutting station 105 will perform the cutting and precutting operations described above. The presents a schematic top view of the multitude of pots 200. The pots are schematically represented by circles, only one of which is designated by the reference sign 201, the others not for the sake of simplicity and clarity. The pots 201 are still attached to each other and thus arrive in the (pre)cutting station 105.

The indicates separation lines 202 along which cutouts are to be made in order to form unit packs. The also indicates score lines 203 along which incisions are to be made. Thanks to these incisions, the packs are divisible into unit pots 201. As indicated above, the cuts and incisions are to be made in intermediate sections connecting the pots 201 to each other. In the example shown in , the packs to be formed include four pots of yoghurts, but it is understood that the packs can include any other number of pots.

Polystyrene is conventionally used as the material for the thermoformable film 106 from which yogurt pot packs are made according to the FFS process described above. Indeed, a polystyrene film having a thickness of approximately 1 mm is easy to cut. To make a cut along a parting line, it is enough for a knife to penetrate about 70% into the polystyrene film along this line. The polystyrene film then fractures along this line resulting in a clean separation. A polystyrene film is also easy to pre-cut: a knife only needs to penetrate about 40% into the polystyrene film to make an incision along a score line. A clean separation can then be achieved by folding along this incision. In addition, the degrees of penetration mentioned here have significant tolerances. This allows relatively easy adjustment of knives in the (pre)cutting station 105 of the FFS 100 machine.

However, polystyrene has an ecological disadvantage: polystyrene is not easily recyclable. From this point of view, it will therefore be advantageous to replace polystyrene as the material for the thermoformable film 106 with another thermoformable material which is more easily recycled.

Polyethylene terephthalate, hereinafter referred to by the commonly used acronym "PET", is a thermoformable material that can be recycled relatively easily. A PET film is suitable for packaging food products such as yoghurt. The PET film can have a thickness between, for example, 500 μm and 1 mm and a density of approximately 1.34 gr/cm3. A film 500 μm thick typically has an oxygen transmission rate, in English "Oxygen Transmission Rate", designated by the acronym OTR, of 6.80 cc/m². The OTR oxygen transmission rate is expressed as the volume of oxygen that enters a given area over a period of one day, measured at a standard temperature of approximately 23°C and 0% relative humidity. This film also typically has a moisture vapor transmission rate, designated by the acronym MVTR, of 0.40 cc/m2. The water vapor transmission rate MVTR, also called water vapor transmission rate, in English "Water Vapor Transmission Rate" designated by the acronym WVTR, is a measure of the passage of water vapor through the film.

A PET film can be obtained by extruding a PET raw material heated to around 270°C. The raw material then becomes liquid and can thus be transformed into a film, which will typically be flexible or transparent. With rapid cooling during calendering, the PET film is frozen in an amorphous state, more precisely, in a semi-crystalline state. In fact, PET, as well as other polymers, can be characterized by a degree of crystallinity. A polymer generally cannot be completely crystalline. Most polymers are semi-crystalline with a maximum of about 80% crystallinity.

However, the following aspects militate against a replacement of polystyrene by PET to manufacture yoghurt pot packs or other types of products manufactured in the form of divisible packs. A PET film having a thickness of approximately 500 μm or 1 mm, obtained as described above, is difficult to cut. To make a cut along a separation line, a knife must penetrate completely, therefore 100%, into the PET film along this line. Failing full penetration, there will remain a bond along the parting line, at least partially. The separation will therefore not be obtained.

A PET film is even more difficult to pre-cut. A knife must penetrate approximately 98% into the PET film to make an incision allowing suitable breakability by manual folding. In addition, a strict tolerance applies to the degree of penetration to make such an incision. If the degree of penetration is slightly less than a nominal degree of penetration, such as 98%, a clean separation by manual bending will be difficult, if not impossible. On the other hand, if the degree of penetration is slightly above the nominal degree of penetration, accidental separation may occur too easily. A pack will not be strong enough. Furthermore, as there is little margin compared to the total penetration, a pre-cutting operation is likely to result in a complete cut and therefore in a separation, already at the manufacturing stage, where an incision for breakability is desired. A knife setting in the (pre)cutting station 105 of the FFS 100 machine shown in will be delicate and therefore difficult.

The schematically illustrates an advanced FFS machine 300 allowing economical manufacture of yogurt pot packs from PET film 301. The advanced FFS machine 300 has similarities with the FFS machine 100 described above with reference to the . This last machine will be called base 100 FFS machine in what follows. In this embodiment, the advanced FFS machine 300 includes the same stations as the basic FFS machine 100: heating stations 302, a forming station 303, a filling station 304, a sealing station 305, and a station of (pre)cutting 306. In addition, these stations can be similar, or even identical, to those of the basic FFS machine 100. Similar to the basic FFS machine 100, a sealing film 307, also in roll form, is coupled to the sealing station 305 of the advanced FFS machine 300.

In fact, the advanced FFS machine 300 can be obtained by adding two stations to the basic FFS machine 100: a first crystallization station 308 and a second crystallization station 309. In the embodiment illustrated in , the first crystallization station 308 is associated with the heating stations 302. The second crystallization station 309 is associated with the sealing station 305.

The PET film 301 in the form of a reel is coupled to an entry section of the advanced FFS machine 300. The PET film 301 therefore replaces the polystyrene film conventionally used to manufacture packs of yoghurt pots by means of the base 100 FFS machine described in the above. The PET film 301 can also have a thickness comprised between, for example, 0.5 mm and 2 mm. The PET film 301 can be obtained as described above. The PET of the film therefore has an amorphous structure, that is to say, a degree of crystallinity of less than 30%.

In essence, the advanced FFS machine 300 operates in a manner similar to that of the basic FFS machine 100 described in the foregoing with reference to the . A section of the PET film 301 located in the heating stations 302 is therefore softened by heating to a temperature which can also be between about 120 to 140° C. as mentioned above. In this regard it should be noted that PET film 301 typically exhibits a glass transition temperature of between about 67° to 81°C. The section of the PET film 301 thus heated in the heating stations 302 retains its flexibility and its amorphous structure.

The first crystallization station 308 heats certain areas of the PET film section 301 to a temperature between 130°C and 180°C, for example, to a temperature of about 160°C. These zones can be heated for a duration between 0.8 s and 6 s. In the zones thus heated, the PET crystallizes: the degree of crystallinity increases in these zones. The first crystallization station 308 therefore causes local crystallization by heating. This local crystallization will be called the first local crystallization hereafter for practical reasons.

The schematically illustrates a multitude of pots 400 still attached to each other in which the local crystallization zones 401 are indicated. The presents a schematic top view of the multitude of pots 400, similar to the . The local crystallization zones 401 are indicated by a dotted pattern. Separation lines 402 and break lines 403 are also indicated. The lines of the separations delimit packs of yoghurt pots to be formed, one pack of which is illustrated in . The dividing lines 403 delimit unit pots in the packs of yoghurt pots to be formed.

The local crystallization zones 401 constitute bands centered on the separation lines 402 and the dividing lines 403. The local crystallization zones 401 are therefore located in the intermediate sections between the yoghurt pots to be formed. In these areas, the intermediate sections can have a thickness between 0.30 mm and 2 mm, depending on the thickness of the PET 301 film from which the advanced FFS 300 machine manufactures the yoghurt pot packs.

The schematically illustrates an example of a heating plate 500 of the first crystallization station 308. The presents a schematic top view of the heating plate 500 showing an active side thereof. First crystallization station 308 may include two such heating plates between which a section of PET film 301 may be sandwiched. The active side of the 500 hot plate shown in includes a raised surface 501 indicated by a dotted pattern. The raised surface 501, which is hot when the first crystallization station 308 is operational, comes into contact with the section of the PET film 301 located in this station. In this example, the first crystallization station 308 then heats a relatively large part of the intermediate sections between the yoghurt pots to be formed.

The forming station 303 of the advanced FFS machine 300 can operate like the forming station 303 of the basic FFS machine 100. Thus, the forming station 303 of the advanced FFS machine 300 sequentially receives softened successive sections of the PET film 301 which, moreover, were crystallized locally. Forming station 303 presses a softened section of PET film 301 into a mold. The forming station 303 thus forms a set of pots which are still attached to each other. The intermediate sections, which connect the pots to each other, comprise local crystallization zones 401 formed in the first crystallization station 308. The set of pots is still attached to a set of downstream pots, formed previously, and to a locally softened and crystallized section upstream. The set of pots is transferred to filling station 304

The filling station 304 of the advanced FFS machine 300 can also function as the filling station 304 of the basic FFS machine 100. The filling station 304 fills the freshly formed pots with yogurt. The pots filled with yogurt are transferred to the sealing station 305. At this stage, the yogurt pots are still attached to each other.

The 305 sealing station of the 300 advanced FFS machine can also function as the 305 sealing station of the 100 basic FFS machine. Thus, the sealing station 305 provides a set of filled and sealed pots which are still attached to each other. The pots filled with yogurt and sealed are transferred to the second crystallization station 309.

The second crystallization station 309 performs a second local crystallization which complements the first local crystallization described above. To do this, the second crystallization station 309 heats certain areas in the intermediate sections connecting the pots to each other to a temperature between 130°C and 180°C, for example, to a temperature of approximately 160°C. These zones can be included in the zones where the first local crystallization took place. In the zones thus heated by the second crystallization station 309, the PET crystallizes even more. The second local crystallization therefore further increases the degree of crystallinity in these areas, which has already been increased by the first local crystallization. The degree of crystallinity can be brought to at least 40% by the second local crystallization coming in addition to the first local crystallization.

The schematically illustrates an example of a heating plate 600 of the second crystallization station 309. The presents a schematic top view of the heating plate 600 showing an active side thereof. The active side of the 600 hot plate shown in includes a set of raised surfaces 601 indicated by a dotted pattern. Only one raised surface is indicated by the reference sign 601, the others not for the sake of simplicity and clarity.

The raised surfaces 601, which are hot when the second crystallization station 309 is operational, come into contact with the intermediate sections between the pots located in this station. In this example, the raised surfaces 601 resemble ribbons which are positioned above the intermediate sections. The second crystallization station 309 then heats elongated portions in the intermediate sections. These elongated parts, which undergo the second local crystallization, are centered on the lines of separation 402 and the lines of sectability 403 indicated in .

The schematically illustrates an example of a pot support 700 which complements the heating plate 600 of the second crystallization station 309. presents a schematic top view of the pot support 700 showing a pot receiving side, referred to as the receiving side hereinafter for convenience. The intermediate sections between the pots located in the second crystallization station 309 are taken into sandwiched between the 600 griddle shown in and the 700 pot holder shown in .

In more detail, the receiving side of the pot rack 700 also includes a set of raised surfaces 701 of which only one is indicated by the reference sign 701, the others not for the sake of simplicity and clarity. These raised surfaces 701 are complementary to and aligned with those 601 of the heating plate 600 of the second crystallization station 309. The elongated parts in the intermediate sections, which undergo the second local crystallization, are therefore sandwiched between on the one hand , the raised surfaces 601 of the heating plate 600 and, on the other hand the raised surfaces 701 of the pot support 700, respectively illustrated in FIGS. 6 and 7. The pot support 700 comprises a set of cavities 702 in which the pots come lodge during the second crystallization. Only one cavity is indicated by the reference sign 702, the others not for the sake of simplicity and clarity.

The (pre)cut station 306 of the advanced FFS machine 300 can mainly function as the (pre)cut station 306 of the basic FFS machine 100. This is thanks to the local crystallization of PET where the lines of separation 402 and the dividing lines 403 illustrated in . In the example presented here, the local crystallization is done in two stages by the first and the second local crystallization. The local crystallization makes the intermediate sections connecting the pots to each other, which are made from the 301 PET film, relatively easy to cut and pre-cut.

The (pre)cutting station 306 of the advanced FFS machine 300 can thus carry out a cutting operation similar to the cutting operation carried out by the basic FFS machine 100, which works from a polystyrene film. The last mentioned cutting operation may be sufficient to separate one set of filled and sealed jars, forming a pack, other sets of filled and sealed jars made, forming other packs, all formed from PET film 301.

The (pre)cut station 306 of the advanced FFS machine 300 can thus perform a pre-cut operation similar to the pre-cut operation performed by the base FFS machine 100. The last-mentioned pre-cut operation may be sufficient to make the pots of a pack divisible. That is to say, an incision of a depth between about 30% to 70% of the thickness of the intermediate sections may be sufficient to allow suitable dividing by manual folding.

The embodiments described in the foregoing with reference to the drawings are presented by way of illustration. The invention can be implemented in many different ways. To illustrate this, some alternatives are briefly indicated.

The invention can be implemented in many types of products and processes related to the manufacture of packs of products that can be split into unit products. By way of illustration, an implementation has been described which concerns the manufacture of packs of yogurt pots. Other implementations may relate to the manufacture of other products containing other semi-liquid foods, or other substances, which, moreover, may be packaged in containers having a shape different from that of a jar. . Furthermore, a pack manufactured in accordance with the invention may, in principle, comprise any number of products, such as, for example, 2, 4, 6, or 8 products which can be broken down into unit products.

There are many amorphous polymer materials from which packs of products can be broken into unitary products in accordance with the invention. In the disclosed embodiments, the amorphous polymeric material is PET. In other embodiments, another amorphous polymeric material can be used such as, for example, polylactic acid commonly referred to by the acronym "PLA". In these other embodiments, temperature ranges other than those indicated for the embodiments shown, may be more appropriate. The same goes for other parameters in the manufacturing process.

There are many ways to implement local crystallization. In the embodiments presented, the local crystallization takes place in two stages: a first local crystallization carried out after softening the amorphous polymer material and before forming the latter, and a second local crystallization carried out after sealing and before (pre-cut. In other embodiments, the local crystallization can be performed in a single step, for example, where the first local crystallization is performed in the embodiments shown, or where the second local crystallization is performed. However, it may be advantageous to carry out the local crystallization in several stages, as in the embodiments presented, or distributed differently which may also involve more than two stages, for example, the introduction of a third local crystallization.

The foregoing remarks show that the embodiments described with reference to the drawings illustrate the invention rather than limit it. The reference signs have no limiting character. The verb "comprise" in a claim does not exclude the presence of other elements or other steps than those listed in the claim. The same goes for similar verbs such as “comport” and “include”.

Claims (11)

Method for manufacturing a pack of products (108) divisible into unitary products (201) from an amorphous polymeric material (301) having a degree of crystallinity of less than 30%, the method comprising:
- the heating (308, 309) of a zone (401) where an incision is to be made so that the amorphous polymer material in this zone undergoes local crystallization bringing the degree of crystallinity to at least 40% in the zone where the incision is to be made; and
- making the incision (306) in the area where the amorphous polymer material has undergone local crystallization, the incision making the pack of products divisible into unitary products A manufacturing method according to claim 1, wherein the unit products (201) are in the form of filled and sealed containers, the method comprising:
- the thermoforming (303) of the containers from the amorphous polymer (301),
in which the heating (308, 309) of the zone (401) where the incision is to be made is at least partially carried out upstream (308) of the thermoforming of the containers Manufacturing process according to claim 2, in which the heating (308, 309) of the zone (401) where the incision is to be made is partially carried out upstream (308) of the thermoforming (303) of the containers and partially carried out downstream (309) thermoforming of containers. A method of manufacture according to any one of claims 1 to 3, wherein the amorphous polymeric material (301) comprises at least one of the following materials: polyethylene terephthalate and polylactic acid. Manufacturing process according to claim 4, in which the zone (401) where an incision is to be made is heated to a temperature of between 130°C and 180°C. Manufacturing process according to either of Claims 4 and 5, in which the zone (401) where an incision is to be made is heated for a period of between 0.8 s and 6 s. Manufacturing process according to any one of Claims 1 to 6, in which the zone (401) where an incision is to be made has a thickness of between 0.30 mm and 2 mm. Manufacturing method according to any one of claims 1 to 7, the method comprising:
- the heating (308, 309) of a zone (401) where a cut is to be made so that the amorphous polymer material in this zone undergoes local crystallization bringing the degree of crystallinity to at least 40% in the zone where the cut is to be made; and
- the production of a cut (306) in the area where the amorphous polymer material has undergone local crystallization, the cut allowing individual handling of the pack of divisible products into unitary products. Manufacturing process according to claim 8, in which the heating (308, 309) of the zone (401) where the incision is to be made and the heating of the zone where the cut is to be made are carried out jointly by means of at least least one local crystallization station. Manufacturing machine (300) of a pack of products (108) divisible into unitary products (201), the machine being able to implement a method according to any one of claims 1 to 9. Pack of products (108) divisible into unitary products (201), the pack of products comprising an amorphous polymeric material (301), the pack of products comprising a part (401) where the amorphous polymeric material has a degree of crystallinity of at least least 40%, the part comprising an incision making the pack of products divisible into unitary products.