FR3132903A1 - Metal packaging with twist-off cap - Google Patents

Abstract

Packaging body 3 comprising an end 31 forming a ring comprising an edge 33, delimiting an access opening to the interior of the body 3, called opening edge, the ring 31 comprising threads 311 intended to cooperate by screwing with a twist-off capsule equipped with a seal, this seal being intended to cooperate with the opening edge 33 of the ring 31 for hermetic closure of the body 3 resistant to heat sterilization, characterized in that It's made of metal. Figure for abstract: figure 2

Description

Metal packaging with twist-off capsule

The invention relates to packaging for the storage and preservation of products, in particular food, by pasteurization and sterilization by heat. It concerns more specifically twist-off packaging.

The twist-off capsule is a metal capsule equipped with lugs. The lugs can be from 3 (for a 27 mm diameter capsule) to 8 (for a 110 mm diameter capsule). The complementary packaging body has as many threads on its ring as there are lugs on the capsule, and each thread cooperates with a lug to ensure the closing or opening of the packaging body by the capsule. Twist-off caps (also called “lug caps” in English) require less than one turn of the ring to close and open (around 1/8 to 1/3 turn depending on the diameters) . They each extend 1/8 to 1/3 of the circumference of the ring. Thus, each thread extends over less than one turn of the ring (from 1/8 to 1/3 of the turn of the ring). The threads are distributed around the ring and adjacent in pairs. They form a discontinuous thread, as opposed to the continuous thread which serves as a guide for the continuous thread of a screw cap.

Twist-off packaging traditionally includes a glass body, which includes a ring intended to cooperate with a twist-off capsule.

To ensure tight closure, from sterilization to opening of the packaging body, the capsule has a groove in which a seal is housed. This ensures sealing by compression on the upper edge of the ring.

Twist-off capsules are for example named as follows:

RTO (Regular Twist Off), RTB (Regular Twist Off with Safety Button), RTS (Twist Off with Step), RTB (Twist off with Step and Safety Button), RTA (Twist Off with Angle), RAB (Twist Off with Angle) and Safety Button), DTO (Depp Twist Off), DTB (Deep Twist Off with Safety Button), MTO (Medium Twist Off), MTB (Medium Twist Off with Safety Button).

The metal lids of glass jars are formed from pasteurizable and sterilizable materials that can withstand high temperatures and are held closed by atmospheric pressure. Glass-metal contact is therefore currently controlled with regard to temperature and pressure variations.

To break the seal and open the packaging body, the capsule is unscrewed. After this first opening, the packaging body can be closed again by screwing the capsule, and opened again by unscrewing.

These twist-off packaging bodies have good sealing performance and resistance to mechanical stress during the sterilization or pasteurization phases, and are widely used for food preservation. However, glass twist-off packaging bodies are fragile and can be easily broken.

Furthermore, less fragile metal packaging bodies are known. However, these packaging bodies are hermetically closed by crimped lids. Indeed, those skilled in the art consider that only the crimping of two metal surfaces in contact can ensure a watertight seal during the sterilization phase. This is due to the fact that, during the sterilization process, the box undergoes drastic thermal and pressure stresses: up to 131°C for 1 hour with internal and/or external overpressures of up to 1.2 bar during the duration of the sterilization process. cycle. The internal pressure increases with temperature and this increase could lead to irreversible deformation and could lead to a breakdown of the seal.

The invention aims in particular to provide twist-off packaging bodies having improved mechanical resistance to stress and shock.

For this purpose the subject of the invention is a packaging body comprising an end forming a ring comprising an edge, delimiting an access opening to the interior of the body, called opening edge, the ring comprising threads intended to cooperate by screwing with a twist-off capsule equipped with a seal. This seal is intended to cooperate with the opening edge of the ring for hermetic closure of the body resistant to heat sterilization. The packaging body is made of metal.

Thus, we propose to provide a metallic twist-off packaging body. This goes against the prejudice of those skilled in the art concerning the behavior of two metallic materials in contact and metal-metal interaction phenomena under the effect of variations in internal and external pressures.

The packaging body according to the invention has the usual advantages of twist-off packaging bodies, namely good resistance to mechanical stress during the sterilization and pasteurization phases, good sealing and impermeability to gases, good compatibility with the majority of products, and in particular solvents, a stability of the materials which allows good conservation of the product and preserves its organoleptic qualities, easy and economically very acceptable recycling, good thermal conductivity, excellent resistance to internal pressure and a good resistance to ionizing radiation. We can also easily print on this metal packaging. Finally, the metal packaging body has good stacking strength and good resistance to stacking.

It also has great mechanical resistance to stress and shock and helps protect the contents from solar radiation. Also, the use of metal, easier to use and transport than glass, has advantages, both in terms of manufacturing and transport and storage of containers. Due to its metal construction, we can also consider using magnetism, for example to hold the packaging body during capping. In addition, this packaging body makes it possible to “hide” its contents from the eyes of the user, which is advantageous for contents whose appearance is not pleasant. The weight of the metal packaging is also much lower (around 80% less weight), which improves transport possibilities.

Compared to crimped metal cans, it is easy to open, resealable, handling presents less risk (less risk of cuts). It also has a more modern image.

Compared to other closure systems, for example the press-on turn-off system, the twist-off system can be developed for a wide variety of diameters. opening (large diameters suitable for poorly hydrated products and small diameters for liquids). It requires less force to open. It can be used to make both two-piece boxes (with a pressed bottom) and three-piece boxes (with a crimped bottom).

A packaging body is hermetically closed when it is tight against gases and liquids, and against any external contamination.

“Heat sterilization” means a process which consists of heating the packaging body to a temperature at least equal to 100°C. The duration and temperature vary depending on the type of food as well as the packaging used, in order to prevent microorganisms from surviving and developing inside the packaging body.

An airtight seal resistant to heat sterilization withstands a temperature of at least 100°C, and can go up to 131°C.

The packaging body may include other optional characteristics, taken alone or in combination, specified below.

- The packaging body is formed of a metal sheet whose thickness ranges from 0.15 to 0.27 mm, preferably from 0.17 to 0.25 mm, even more preferably from 0.19 to 0.25 mm. 0.23 mm, and the hardness ranges from TS260 to TH580 in accordance with standard NF EN 10202 of January 2002, preferably less than or equal to TH435, and more preferably from TS290 to TH415.
Such a packaging body has improved internal pressure resistance, particularly suitable for use in heat sterilization. Furthermore, the hardness is preferably less than or equal to TH435 because a higher hardness makes it difficult to manufacture the packaging body if expansion or shrinkage must be carried out.

- There are three to eight threads distributed along the circumference of the ring. Each thread can thus cooperate with a lug of a twist-off capsule having a number of lugs identical to the number of threads, thus ensuring the closure of the container. Advantageously, the threads are adjacent in pairs.

- Each thread extends 1/8 to 1/3 of the circumference of the ring. Thus, less than one turn of the ring is required to open or close the container.

The invention also relates to a packaging comprising a packaging body as described above, and a twist-off capsule intended to cooperate by screwing with the threads of the packaging body, the capsule being equipped with a seal sealing device intended to cooperate with the opening edge of the body ring for hermetic closure of the body resistant to heat sterilization.

The packaging may include other optional features, taken alone or in combination, specified below.

- The seal is made of a thermoplastic elastomer material, and is able to resist heat sterilization.
The term “thermoplastic elastomer” means a plastic material capable of deforming plastically by heating, and of deforming elastically at room temperature. The joint according to the invention does not contain PVC (polyvinyl chloride), and is not formulated from substances containing it.
The seal is said to be “capable of resisting heat sterilization”, meaning it will retain its sealing properties even after a sterilization process of up to 131°C. The heat sterilization temperature is at least equal to 100°C and at most equal to 131°C.

Such materials are described for example in document US2015/0028035. The brand products PROVALIN 1241, PROVALIN 1288 and PROVALIN 1269 from ACTEGA DS GmbH (Straubinger Str. 12, Box 107701, 28219 Bremen, Germany) can be used.

Such a seal ensures optimal hermetic closure, resistant to heat sterilization. Furthermore, it has an optimized interaction with the opening edge of the ring of the metal packaging body, facilitating opening of the packaging body.

- The twist-off capsule comprises a panel and a skirt comprising at its outer end a rolled edge extending radially inwards, the rolled edge comprising lugs, preferably three to eight lugs distributed over the circumference of the outer end of the rolled edge, and each lug is intended to cooperate with a thread of the packaging body, by direct contact between the thread and the lug. The capsule can thus be screwed onto the packaging body so as to make the seal cooperate with the opening edge of the body, thus allowing its hermetic closure.

Finally, the subject of the invention is a method of manufacturing a packaging body as described above. The manufacturing process includes the following steps:
- we carry out during a so-called “rolling” step rolling outwards or inwards of a free edge of a part of a ferrule, called “connecting part with the capsule”, so as to form an opening edge of the packaging body,
- before or after the rolling stage, threads are formed on the connecting part.

By ferrule we mean a hollow cylindrical part of constant radius, with or without a bottom. A bottomless ferrule can be obtained by electrically welding a metal sheet to give it a hollow cylindrical shape. Such a bottomless ferrule can be used in the manufacturing process according to the invention.

A base can be assembled to this cylindrical part by crimping, before implementing the manufacturing process. In this case, the ferrule used in the process will be with bottom. Alternatively, the bottom can be added by crimping during a subsequent stage of manufacturing the packaging body. A bottomless shell makes it possible to manufacture a box in three elements (side wall of the packaging body, bottom of the packaging body and capsule).
A ferrule, with an integrated bottom, can also be obtained by stamping a metal sheet to give it a hollow cylindrical shape with a bottom. A ferrule with integrated bottom makes it possible to manufacture a box in two elements (packaging body and capsule).

Due to the fact that the packaging body has several areas of fragility (diameter change area, threaded area), its manufacturing is not easy. Such a process makes it possible to obtain a packaging body having the expected shape, for its use in heat sterilization.

The process may include other optional characteristics, taken alone or in combination, specified below.

- First and second parts of different diameters are formed, the first part having a diameter less than that of the second part.

- The first part is made by shrinking the ferrule. This process not only allows the manufacture of three-piece boxes, but also the manufacture of two-piece boxes. The first part can be obtained by one or more shrinkage steps.
Advantageously, the rolling step is carried out after the shrinking step(s).
Optionally, the threads are obtained by rolling using wheels.
Advantageously, the threading is carried out after the shrinking and rolling steps.

- The method further comprises a step of edging outwards a free edge of the ferrule opposite the free edge of the ferrule intended to be rolled. This allows, to obtain a box in three elements, to assemble the shell to a base by crimping.
Advantageously, the planking is carried out at the same time as the rolling step, before forming the threads.
Optionally, the method further comprises a step of molding the second part of the shell.
Advantageously, this step is subsequent to the shrinking, rolling, edging and threading steps.

- We carry out the second part by expansion of the ferrule. This makes it possible to carry out at the same time the formation of the second part and the formation of the threads in the case where these are manufactured by expansion. This therefore makes it possible to reduce the manufacturing time of the packaging body. Optionally, the threads are obtained by rolling using wheels.

- The method further comprises a step of edging a free edge of the ferrule opposite the free edge of the ferrule intended to be rolled. This allows, to obtain a box in three elements, to assemble the shell to a base by crimping.
Advantageously, the planking is carried out after the rolling and expansion stages.

- Rolling is carried out before the expansion stage allowing the realization of the second part. When rolling is carried out before generating a change in diameter, and forming the threads, we avoid causing a collapse of these areas which are fragile. This is therefore an improvement of the process, favoring obtaining a packaging body suitable for use in heat sterilization, with a twist-off capsule.
Alternatively, rolling is carried out after the expansion step, if the process requires it for reasons of simplification of manufacturing.
Alternatively, the planking is carried out at the same time as the rolling, before forming the fillets.

- The first or second part forms the ring.

Brief description of the figures

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the appended drawings in which:

there is a perspective view of a package according to one embodiment of the invention (body and cover);

there is a perspective view of the body of the ;

there is a perspective view of the capsule of the ;

there is a longitudinal sectional view of part of the packaging of the ;

Figures 5a and 5b are sectional views of a ferrule illustrating different stages of formation of the packaging body according to a first embodiment of the invention;

Figures 6a, 6b and 6c are sectional views of a ferrule illustrating different stages of formation of the packaging body according to a second embodiment of the invention;

Figures 7a, 7b, 7c and 7d are sectional views of a ferrule illustrating different stages of formation of the packaging body according to a third embodiment of the invention;

Figures 8a, 8b and 8c are sectional views of a ferrule illustrating different stages of formation of the packaging body according to a fourth embodiment of the invention;

Figures 9a, 9b and 9c are sectional views of a ferrule illustrating different stages of formation of the packaging body according to a fifth embodiment of the invention.

detailed description

Figures 1 to 4 show packaging according to one embodiment of the invention, designated by the general reference 1. Packaging 1 comprises a packaging body 3 and a twist-off capsule 5.

The packaging body 3 has an end 31 forming a ring comprising an edge 33, delimiting an access opening to the interior of the body 3, called the opening edge. The ring 31 comprises threads 311 intended to cooperate by screwing with the twist-off capsule 5 which is equipped with a seal 7, visible in particular on the . On the , the thickness of the joint is not necessarily represented to scale. This seal 7 is intended to cooperate with the opening edge 33 of the ring 31 for hermetic closure of the body 3 resistant to heat sterilization. The packaging body 3 is made of metal.

The packaging body 3 is formed of a metal sheet 35 whose thickness ranges from 0.15 to 0.27 mm, and the hardness ranges from TS260 to TH580 in accordance with standard NF EN 10202 of January 2002.

The twist-off capsule 5 comprises a panel 51 and a skirt 53 comprising at its outer end a rolled edge 531 extending radially inwards. The rolled edge 531 comprises lugs 5313. In the embodiment of Figures 1 to 4, the capsule 5 comprises six lugs 5313 visible in particular on the . This number of six lugs is given as an example. There may, however, be more or less than six lugs. The lugs 5313 are distributed over the circumference of the outer end of the rolled edge 531, and each lug 5313 is intended to cooperate with a thread 311 of the packaging body 3, by direct contact between the thread 311 and the lug 5313, as illustrated in particular on the .

In the embodiment of Figures 1 to 4, there are six threads 311 of the packaging body 3. They are distributed along the circumference of the ring 31. In this embodiment, each thread extends over 1/6 of the circumference of the ring. They are adjacent two by two.

The seal 7 is made of a thermoplastic elastomer material, and is able to resist heat sterilization.

Figures 5a and 5b show sectional views of a ferrule 5005 illustrating different stages of formation of the packaging body 5003 according to a first embodiment of the invention. The steps are shown in the order in which they are performed.

The formation of the 5003 packaging body includes the following steps:
- we carry out during a so-called “rolling” step, shown in Figure 5a, an inward rolling of a free edge 50053 of a part 50051 of the ferrule 5005. This part 50051 of the ferrule is called the “connecting part with the capsule”. The rolling step is carried out so as to form an opening edge 5033 of the packaging body 5003;
- after the rolling step, threads 5311 are formed (figure 5b) on the connecting part 50051.

In this embodiment, a straight packaging body is manufactured, of constant diameter with the exception of the threading zone. The rolling is towards the inside, so as to allow the screwing of the capsule.

In this embodiment, the threads are obtained by rolling using wheels.

In this embodiment, the ferrule 5005 is a ferrule with an integrated bottom. It can be obtained by stamping a metal sheet. It has a hollow cylindrical shape with a bottom.

In the variant shown in Figures 5, a molding 5007 is also produced. It is carried out by rolling. The molding is optional. Its presence, creating an area of larger diameter, prevents the capsules from colliding and unscrewing during handling.

The other embodiments shown include the same rolling and thread forming steps, but the rolling is carried out outwards. In what follows, only the differences compared to this first embodiment will be mentioned.

In the embodiment of Figures 6a to 6c, a first part 60055 and a second part 60057 are also formed, during a step prior to the rolling and thread forming steps 6311. This prior step is shown in the figure 6a. In this embodiment, the first part 60055 is produced by necking, and more precisely here, there were several necking steps. In this embodiment, the first part 60055 forms the ring 6031.

In the embodiment of Figures 7a to 7d, the ferrule 7005 is a bottomless ferrule. Compared to the method shown in Figures 6a to 6c, the present method further comprises a step of edging outwards a free edge 70059 of the ferrule opposite the free edge 70053 of the ferrule intended to be rolled. This allows, to obtain a box in three elements, to assemble the shell to a base by crimping. The planking step is shown in Figure 7b. In this embodiment, the planking is carried out at the same time as the rolling step, before forming the threads 7311. This embodiment further comprises a step of molding the second part 70057 of the ferrule, shown on the Figure 7d. This molding step is optional. In this embodiment, the subsequent crimping step is not shown. The packaging body is therefore not shown.

In the embodiment of Figures 8a to 8c, the second part 80057 and the threads 8311 are produced by expansion. Alternatively, the second part can be produced by expansion, and the threads can be obtained by rolling using rollers. In this embodiment, the planking is carried out after the formation of the nets. The first part forms the ring 8031.

In the embodiment of Figures 9a to 9c, the second part 90057 and the threads 9311 are produced by expansion. In this embodiment, the second part 90057 forms the ring 9031.

The invention is not limited to the embodiments presented and other embodiments will be clear to those skilled in the art.

Reference list

1: packaging
3, 5003, 6003: packaging body
31, 5031, 6031, 7031, 8031, 9031: ring
311, 5311, 6311, 7311, 8311, 9311: net
33, 5033, 6033, 7033; 8033, 9033: opening edge
35: metal foil
5: twist-off capsule
51: panel
53: skirt
531: rolled edge
5313: lug
7: seal
5005, 6005, 7005, 8005, 9005: ferrule
50051, 60051, 70051, 80051, 90051: connection part with the capsule
50053, 60053, 70053, 80053, 90053: free edge of the connecting part
60055, 70055, 80055, 90055: first part
60055d, 70055d, 80055d, 90055d: diameter of the first part
60057, 70057, 80057, 90057: second part
60057d, 70057d, 80057d, 90057d: diameter of the second part
70059, 80059, 90059: free edge intended to be edged
5007: molding

Claims (15)

Packaging body (3, 5003, 6003) comprising an end (31, 5031, 6031, 7031, 8031, 9031) forming a ring comprising an edge (33, 5033, 6033, 7033; 8033, 9033), delimiting an opening access to the interior of the body (3), called the opening edge, the ring (31, 5031, 6031, 7031, 8031, 9031) comprising threads (311, 5311, 6311, 7311, 8311, 9311) intended to cooperate by screwing with a twist-off capsule (5) equipped with a seal (7),
this seal (7) being intended to cooperate with the opening edge (33, 5033, 6033, 7033; 8033, 9033) of the ring (31, 5031, 6031, 7031, 8031, 9031) for hermetic closure of the body (3, 5003, 6003) resistant to heat sterilization,
characterized in that it is made of metal. Packaging body (3, 5003, 6003) according to the preceding claim, formed of a metal foil (35) whose thickness ranges from 0.15 to 0.27 mm, preferably from 0.17 to 0.25 mm, even more preferably from 0.19 to 0.23 mm, and the hardness ranges from TS260 to TH580 in accordance with standard NF EN 10202 of January 2002, preferably less than or equal to TH435, and more preferably from TS290 to TH415. Packaging body (3, 5003, 6003) according to any one of the preceding claims, in which the threads (311, 5311, 6311, 7311, 8311, 9311) are three to eight in number, distributed along the ring circumference (31, 5031, 6031, 7031, 8031, 9031). Packaging body (3, 5003, 6003) according to any one of the preceding claims, in which each thread (311, 5311, 6311, 7311, 8311, 9311) extends over 1/8 to 1/3 of the ring circumference (31, 5031, 6031, 7031, 8031, 9031). Packaging (1) comprising a packaging body (3, 5003, 6003) according to any one of the preceding claims and a twist-off capsule (5) intended to cooperate by screwing with the threads (311, 5311, 6311, 7311 , 8311, 9311) of the packaging body (3, 5003, 6003), the capsule (5) being equipped with a seal (7) intended to cooperate with the opening edge (33, 5033, 6033 , 7033; 8033, 9033) of the ring (31, 5031, 6031, 7031, 8031, 9031) of the body (3, 5003, 6003) for hermetic closure of the body (3, 5003, 6003) resistant to sterilization at the heat. Packaging (1) according to the preceding claim, in which the seal (7) is made of a thermoplastic elastomer material, and is capable of resisting heat sterilization. Packaging (1) according to claim 5 or 6, in which the twist-off capsule (5) comprises a panel (51) and a skirt (53) comprising at its outer end a rolled edge (531) extending radially towards the inside, the rolled edge (531) comprising lugs (5313), preferably three to eight lugs (5313) distributed over the circumference of the outer end of the rolled edge (531), and each lug (5313) is intended to cooperate with a net (311, 5311, 6311, 7311, 8311, 9311) of the packaging body (3, 5003, 6003), by direct contact between the net (311, 5311, 6311, 7311, 8311, 9311) and ergot (5313). Method of manufacturing a packaging body (5003, 6003) according to any one of claims 1 to 4, comprising the following steps:
- we carry out during a so-called “rolling” step rolling outwards or inwards of a free edge (50053, 60053, 70053, 80053, 90053) of a part (50051, 60051, 70051, 80051, 90051) of a ferrule (5005, 6005, 7005, 8005, 9005), called “connecting part with the capsule”, so as to form an opening edge (33, 5033, 6033, 7033; 8033, 9033) of the packaging body (3, 5003, 6003 ),
- before or after the rolling step, threads (311, 5311, 6311, 7311, 8311, 9311) are formed on the connecting part (50051, 60051, 70051, 80051, 90051). Manufacturing method according to the preceding claim, in which first (60055, 70055, 80055, 90055) and second (60057, 70057, 80057, 90057) parts of the ferrule ( 6005, 7005, 8005, 9005 ) are formed with diameters ( 60055d, 70055d, 80055d, 90055d, 60057d, 70057d, 80057d, 90057d) different, the first part (60055, 70055, 80055, 90055) having a diameter (60055d, 70055d, 80055d, 90055d) lower than that (60057d, 70057d, 80057d, 90057d) of the second part (60057, 70057, 80057, 90057). Manufacturing method according to the preceding claim, in which the first part (60055, 70055) is produced by shrinking the ferrule (6005, 7005). Manufacturing method according to any one of claims 8 to 10, further comprising a step of edging outwards a free edge (70059) of the ferrule (7005) opposite the free edge (70053) of the ferrule intended to be rolled. Manufacturing process according to claim 9, in which the second part is carried out (80057, 90057) by expansion of the ferrule (8005, 9005). Manufacturing method according to the preceding claim, further comprising a step of edging a free edge (80059, 90059) of the ferrule (8005, 9005) opposite the free edge (80053, 90053) of the ferrule intended to be rolled. Manufacturing method according to claim 12 or 13, in which the rolling is carried out before the expansion step allowing the production of the second part (80057, 90057).
Manufacturing method according to any one of claims 8 to 13, in which the first (60055, 70055, 80055) or the second part (90057) forms the ring (6031, 7031, 8031, 9031).