FR3112125A1 - Metal tin can comprising a metal can body and a metal cover, assembled by a peel-off tab - Google Patents

Abstract

The present invention relates to a metal tin can comprising a can body (2), a metal cover (3) and a peelable tab (4) which is sealed by a heat-sealing material. The peelable tab (4) comprises: - a first longitudinal section (45), an inner face (451) of which is sealed with the metal cover (3) / metal box body (2) pair, - a second longitudinal section (46) covering an upstream portion (453) of said first longitudinal section (45), the interior face (461) of said second longitudinal section (46) being sealed with an exterior face (4532) of said upstream portion ( 453) of said first longitudinal section (45), which peelable tongue (4) comprises an intermediate transverse portion (47), corresponding to the transition between said first longitudinal section (45) and said second longitudinal section (46), and said metal tin can (1) comprises sealing means (6) which are provided to close a transverse space (E1) formed between the inner face (471) of said intermediate transverse portion (47) and the metal cover pair (3) / metal box body (2). Figure for the abstract: 3

Description

Metal tin can comprising a metal tin body and a metal lid, assembled by a peelable tab

Technical field of the invention

The present invention relates to the technical field of metal cans.

It relates in particular to metal cans comprising a metal can body and a metal lid adapted to close an access opening of said metal can body, assembled by a peelable tab.

State of the art

Metal cans are commonly used for packaging foodstuffs. Such cans can also be used for packaging other industrial products, such as paints.

Some metal tin cans include:

- a metal box body comprising a side wall, a first end of which is connected to a bottom and a second end of which delimits an access opening,

- a metal cover adapted to close off said access opening, which metal cover comprises a peripheral skirt which comprises an interlocking strip adapted to cooperate by interlocking with said second end of the side wall, and

- a peelable tab which is sealed, by a heat-sealing material, on the circumference of the peripheral skirt of the metal cover and of the second end of the side wall of the metal box body.

The seal between the metal can body and the metal lid is often essential to ensure optimal preservation of the product packaged in the metal can.

In practice, it is advantageous to ensure this seal directly by means of the peelable tab.

However, current solutions for positioning the peelable tab unfortunately do not offer optimal sealing over the entire circumference of the metal can body.

It would therefore be interesting to offer a metal can in which the peelable tab would ensure an effective seal over the entire circumference.

Presentation of the invention

In order to remedy the aforementioned drawback of the state of the art, the present invention proposes a new metal tin can structure in which the peelable tab provides effective sealing over its entire circumference.

More particularly, according to the invention, a metal can comprising:

- a metal box body comprising a side wall, a first end of which is connected to a bottom and a second end of which delimits an access opening,

- a metal cover adapted to close off said access opening, which metal cover comprises a peripheral skirt which comprises an interlocking strip adapted to cooperate by interlocking with said second end of the side wall, and

- a peelable tab which is sealed, by a heat-sealing material, on the circumference of the peripheral skirt of the metal cover and of the second end of the side wall of the metal box body.

The peelable tab features:

- a first longitudinal section, one inner face of which is sealed with the metal cover/metal box body couple, and

- A second longitudinal section covering an upstream portion of said first longitudinal section, the inner face of said second longitudinal section being sealed with an outer face of said upstream portion of said first longitudinal section.

This peelable tab further comprises an intermediate transverse portion, corresponding to the transition between said first longitudinal section and said second longitudinal section.

And said tin can comprises sealing means which are provided to close off a transverse space which is provided between the inner face of said intermediate transverse portion and the metal cover/metal can body couple.

Such an arrangement of the peelable tab thus ensures optimum sealing over the entire circumference of the metal can, including within the transverse space.

Other non-limiting and advantageous characteristics of the product/process in accordance with the invention, taken individually or in all technically possible combinations, are the following:

- the peelable tab has two parallel longitudinal edges, the upstream portion of said first longitudinal section has a transverse edge extending non-perpendicular to said longitudinal edges and the sealing means are formed by the fusible material which fills the transverse space; the transverse edge of the upstream portion of said first longitudinal section advantageously comprises at least one V-shaped portion, preferably one V-shaped portion or two juxtaposed V-shaped portions;

- The sealing means are formed by at least one molding (preferably at least two or three moldings) provided at least in the intermediate transverse portion, which at least one molding consists of a convex molding on the side of the inner face; said intermediate transverse portion advantageously comprises several parallel moldings, distributed over the circumference of said peelable tab; the parallel moldings are preferably inclined with respect to the two longitudinal borders;

- the sealing means comprise an additional heat-sealing material attached at least to the space provided between the inner face of the intermediate transverse portion and the pair of metal cover/metal box body; which additional heat-sealing material is also advantageously attached between the inner face of the second longitudinal section and the outer face of said upstream portion of said first longitudinal section; the additional heat-sealing material is advantageously applied in a localized manner, or in a homogeneous manner, on the circumference of the metal lid/metal box body pair;

- the metal tin can comprises an adhesive strip which is attached between the inner face of the second longitudinal section and the outer face of said upstream portion of said first longitudinal section, or even in the space provided between the inner face of the intermediate transverse portion and the metal cover / metal box body couple;

- the peelable tab and the metal cover/metal box body pair together define at least one chamber; a filler seal fills said at least one chamber at least over the length of the intermediate transverse portion; the filler seal advantageously also extends opposite the inner face of the first longitudinal section and/or between the inner face of the second longitudinal section and the outer face of said upstream portion of said first longitudinal section;

- the second longitudinal section is extended by a terminal section to form a traction element for the user (possibly comprising a through hole or embossing).

The present invention further comprises a process for the manufacture of a metal tin can.

The manufacturing process according to the invention comprises:

(i) a step of supplying the following parts:

- the metal box body comprising a side wall, a second end of which delimits an access opening,

- the metal cover, adapted to close said access opening, and

- the peelable tab,

(ii) a step of closing said metal tin can during which:

- said metal cover is positioned at said access opening of the metal box body, and

- the metal cover is sealed at the level of the access opening of the metal box body, by heat-sealing said peelable tab on the circumference of the peripheral skirt of the metal cover and of the second end of the side wall of the box body metallic,

which peelable tab is arranged to comprise:

- a first longitudinal section, an inner face of which is provided facing and on the circumference of the pair of metal cover/metal box body,

- a second longitudinal section covering an upstream portion of said first longitudinal section, the inner face of said second longitudinal section being sealed with an outer face of said upstream portion of said first longitudinal section, and

- an intermediate transverse portion, corresponding to the transition between said first longitudinal section and said second longitudinal section.

The method further comprises a sealing step designed to close off the transverse space formed between the inner face of said intermediate transverse portion and the pair of metal cover/metal box body.

Preferably, the sealing step is chosen from at least one of the following steps:

(i) a step of providing a peelable tab, the upstream portion of the first longitudinal section of which includes a transverse border extending non-perpendicular to said longitudinal borders,

(ii) a step of molding the peelable tab to form at least one molding formed at least in the intermediate transverse portion,

(iii) a step of filling a longitudinal chamber with the filler seal (again advantageously to serve as a support and bring together the conditions for optimal heat sealing; preferably, the filler seal adheres to the other elements),

(iv) a step of applying an additional heat-adhesive material, advantageously localized or homogeneous.

Of course, the different characteristics, variants and embodiments of the invention can be associated with each other in various combinations insofar as they are not incompatible or exclusive of each other.

Detailed description of the invention

In addition, various other characteristics of the invention emerge from the appended description made with reference to the drawings which illustrate non-limiting forms of embodiment of the invention and where:

is a general and schematic view, according to a transverse sectional plane, of a metal can according to the invention;

is a schematic view, partial and enlarged, of the metal tin can according to the , showing the peelable tab sealed on the circumference of the metal cover/metal box body couple;

is a partial and enlarged schematic view of the peelable tab, according to a longitudinal section plane, at the level of its intermediate transverse portion;

is a schematic view illustrating variants (4A., 4B., 4C. and 4D.) of the upstream transverse edge of the peelable tab, covered by the intermediate transverse portion;

is a very schematic view which illustrates the heat-sealing operation of the peelable tab on the circumference of the pair of metal cover/metal box;

is a schematic view showing (6A., 6C. or 6D.) moldings provided in particular in the intermediate transverse portion of the peelable tab and (6B.) a tool suitable for obtaining such moldings;

is a schematic view, partial and enlarged, of the metal tin can according to the , showing a filler seal which fills the chambers formed between the peelable tab and the pair of metal cover/metal box body;

is a schematic view, partial and enlarged, of the metal tin can according to the , showing a filler joint which extends between the second longitudinal section and the upstream portion of the first longitudinal section;

is a partial and enlarged schematic view of the peelable tab, along a longitudinal section plane, at its intermediate transverse portion and in which an adhesive strip is added between the second longitudinal section and the upstream portion of said first longitudinal section.

It should be noted that, in these figures, the structural and/or functional elements common to the different variants may have the same references.

The metal can 1 according to the invention, illustrated in particular in Figures 1 and 2, comprises:

- a metal box body 2 (also called "box body 2") comprising a side wall 21 connected to a bottom 22 and comprising an access opening 23,

- a metal cover 3 (also called "cover 3") adapted to cooperate by interlocking with the side wall 21 of said metal box body 2 to close said access opening 23, and

- a peelable tab 4 which is sealed, by a heat-sealing material, on the circumference of the couple formed by the metal lid 3 / the side wall 21 of the box body 2.

In general, the heat-sealing material is also called “heat-sealing material”.

The term “fusible material” also means a material capable of being activated to perform a sealing (or bonding) function when it is subjected to heating (for example local heating by conduction or induction).

This heat-sealing material is for example chosen from polypropylene or polyethylene (for example in the form of a heat-sealing varnish which advantageously consists of a polymer matrix and a dispersion of polypropylene).

Such a peelable tab 4 is thus advantageously attached to the couple formed by the metal cover 3/the side wall 21 of the box body 2, by an action combining heat and pressure, for a suitable time.

The opening of the tin can 1 will advantageously consist in exerting a pull on the peelable tab 4, advantageously at the level of an end portion (forming a gripping/pulling member) described below.

During this traction, the peelable tab 4 gradually detaches from the circumference of the tin can 1 by crack propagation, by a phenomenon of cohesive or adhesive rupture (depending on the nature and composition of the fusible material used).

Once the peelable tab 4 has been detached, the metal lid 3 is released and can be separated from the metal box body 2.

According to the invention, the peelable tab 4 here also provides effective sealing over the entire circumference of the metal converse box 1.

These various technical characteristics of the metal can 1 according to the invention are described below in relation to the figures.

Canister body

The can body 2, generally illustrated in Figures 1 and 2, therefore comprises a side wall 21, defining a longitudinal axis 2 ', delimited by two ends:

- a first end 211 is connected to the bottom 22, and

- A second end 212 delimits the access opening 23 (opposite the bottom 22).

The side wall 21 may for example have a generally cylindrical or parallelepiped/oblong shape.

The side wall 21 and the bottom 22 can be in one piece (forming a two-piece box). Alternatively, the bottom 22 is attached to the side wall 21, for example by crimping (forming a three-piece box).

The second end 212 of the side wall 21 (opposite the bottom 22) advantageously comprises a roll 25 ( ).

By "rolled" is meant in particular a rolling of the material on itself.

The roll 25 of the side wall 21 is here oriented (also called "rolled up") towards the outside (of the tin can 1).

Alternatively, not shown, the roll 25 of the side wall 21 can be oriented (also called "rolled up") towards the inside (of the tin can 1).

The second end 212 may also comprise an end band 26, advantageously of constant circular or oblong horizontal section (perpendicular to the longitudinal axis 2'), connected to the roll 25. This end band 26 is thus underlying the rolled 25.

This end strip 26 advantageously has a general shape identical to the side wall 21, for example a generally cylindrical or parallelepiped/oblong shape.

This end strip 26 advantageously forms a sealing strip 26, which can be sealed with the peelable tab 4.

Indeed, the second end 212 of the side wall 21 (via the roll 25 and/or the end strip 26) is advantageously intended to be sealed with a lower strip 41 of the peelable tab 4.

metal lid

The metal cover 3 is adapted to close off the access opening 23 of the metal box body 2.

This metal cover 3, illustrated in Figures 1 and 2 in particular, comprises a peripheral skirt 31, defining a longitudinal axis 3', which comprises:

- an interlocking strip 311, adapted to cooperate by interlocking with the second end 212 of the side wall 21 of the can body 2 and, preferably,

- a sealing strip 312 intended to be sealed with an upper strip 42 of the peelable tab 4.

The interlocking strip 311 advantageously has a general shape complementary to the roll 25 of the can body 2, for example a general circular or oblong shape.

The interlocking band 311 here comprises a concave surface 311a (outer), here male, which is complementary to at least a part of the roll 25 of the box body 2.

The sealing strip 312 of this metal cover 3 advantageously has a general shape identical to the side wall 21 of the metal box body 2, for example a general cylindrical or parallelepiped/oblong shape.

This sealing strip 312 (overlying) is preferably connected to the interlocking strip 311 (underlying) and extends in the extension of the roll 25 of the box body 2 (even in the size of the strip end 26 of the box body 2).

The interlocking strip 311 then forms a recess with respect to the sealing strip 312.

Again generally, the metal cover 3 comprises a disc 34 extended by the peripheral skirt 31.

This disc 34 has two opposite faces:

- a lower face 341, intended to be oriented towards the inside of the metal tin can 1, and

- an upper face 342, intended to be oriented towards the outside of the metal tin can 1.

The peripheral skirt 31 here advantageously extends from the side of the upper face 342 of the disc 34, to together form a metal lid 3 in the form of a cup.

This metal cover 3 is advantageously produced by forming operations of a metal side.

Again generally, the peripheral skirt 31 ends in a roll 37 (upper).

Here again, by "rolled" is meant in particular a rolling of the material on itself.

This roll 37 advantageously has, seen from above, a general shape identical to the peripheral skirt 31, for example a general circular or oblong shape.

The roll 37 is here oriented (also called "rolled") outward (of the tin can 1), opposite the disk 34 (and the longitudinal axis 2').

Alternatively, not shown, the roll 37 is oriented (also called "rolled up") inwards (of the tin can 1), opposite the disc 34 (and the longitudinal axis 2'). Such an embodiment would reduce the radial size of the metal cover 3.

Peelable tab

The peelable tab 4 ensures (or at least “participates in”) the assembly, hermetic (to fluids, including gases and liquids), between the metal lid 3 and the side wall 21 of the box body 2.

This peelable tab 4 is therefore sealed, by the fusible material, on the circumference, on the one hand, of the peripheral skirt 31 of the metal cover 3 and, on the other hand, of the second end 212 of the side wall 21 of the box body 2.

The peelable tab 4 can be chosen from the conventional peelable tabs 4 per se.

Traditionally, the peelable tab 4 comprises several layers:

- an outer base layer, also called "barrier layer", made of a resistant and flexible material, for example aluminum, and

- an inner sealing layer, adapted in particular to ensure the sealing with the metal parts 2, 3 (box body 2 and cover 3) and to ensure the sealing of the metal tab 4 on itself (as described by the sequel in connection with ).

The base layer advantageously has a mechanical structural function (holding of the two metal parts 2, 3 during sterilization against pressure, preventing untimely perforation, etc.).

This base layer has for example an aluminum thickness ranging from 20 to 150 µm.

The sealing layer can be composed of different sub-layers (not shown), namely:

- an adhesive underlayer, consisting for example of polypropylene grafted with maleic anhydride and having a thickness of 2 to 15 micrometers,

- a peeling underlayer, consisting for example of a mixture of polyethylene and polypropylene, having a thickness of 15 to 80 micrometers.

To facilitate its peeling, this peelable tab 4 may also include a gripping or pulling tab ( ), intended to facilitate the separation of the peelable tab 4 from the metal parts 2, 3 by the consumer.

In this case, "peelable tab 4" means in particular an elongated member, advantageously of rectangular outline.

The peelable tab 4 is delimited, advantageously, by:

- two longitudinal edges 4a, advantageously parallel to each other ( ),

- an inner face 4b, intended to be sealed with the metal lid 3/side wall 21 couple of the box body 2 and here on an outer face 4c of this peelable tab 4 rolled up on itself ( ),

- the outer face 4c, opposite, mentioned above ( ), And

- two transverse borders 4d, called “upstream” 4d1 and “downstream” 4d2 ( ).

This peelable tab 4 extends over the entire circumference, and in a continuous manner, of the pair metal cover 3 / box body 2.

In general, this peelable tab 4 advantageously extends in a plane perpendicular to the longitudinal axis 2′, 3′ of the metal cover 3 / box body 2 pair.

The peelable tab 4 is thus sealed, by the heat-sealing material, on:

- the circumference of the peripheral skirt 31 of the metal cover 3 (advantageously on the sealing strip 312), and

- the second end 212 of the side wall 21 of the can body 2 (advantageously on the end strip 26).

According to the invention, as partially illustrated in the , the peelable tab 4 is arranged on the circumference of the metal can 2 with a partial overlap on itself.

The peelable tab 4 thus comprises at least two sections:

- a first longitudinal section 45 which is sealed with the metal lid 3 / metal box body 2 pair (via the aforementioned lower 41 and upper 42 bands), and

- a second longitudinal section 46 which partially covers this first longitudinal section 45.

The first longitudinal section 45 extends over the circumference of the metal cover 3 / metal box body 2 couple (advantageously over 360° or at least approximately over 360°).

The first longitudinal section 45 has two opposite faces ( ):

- an inner face 451, sealed with the pair metal cover 3 / metal box body 2, and

- An opposite outer face 452.

This first longitudinal section 45 further comprises:

- an upstream portion 453 whose outer face 4532 is covered by (sealed with) the second longitudinal section 46, and

- a downstream portion 454 whose outer face 4542 is free (not covered) with respect to the second longitudinal section 46.

This first longitudinal section 45 (and in particular this upstream portion 453) also ends with the upstream transverse edge 4d1 of the peelable tab 4 (FIGS. 3 and 4).

The second longitudinal section 46 has two opposite faces:

- an inner face 461, sealed with the outer face 4532 of the upstream portion 453 of the first longitudinal section 45, and

- An opposite outer face 462.

The second longitudinal section 46 is advantageously extended by a terminal section 48 which is provided to form a traction element for the user.

At least a part of this terminal section 48 is advantageously free with respect to the first longitudinal section 45 for its gripping.

This terminal section 48 comprises for this for example:

- a through hole, or

- an embossing.

In practice, as described below in relation to the , heat sealing is advantageously activated by combined actions of heat and pressure, for a suitable time.

Advantageously, the heat sealing of the peelable tab 4 can be obtained by means of at least one support tool 10, advantageously a support wheel 10.

Said at least one support tool 10 is advantageously intended to travel around the circumference of the peelable tab 4, along its outer face 4c.

The heat-sealing material then advantageously forms a bead of heat-sealing material, or an accumulation of heat-sealing material, which progresses upstream of this bearing tool 10.

In practice, the opening of the tin can 1 will advantageously consist in exerting a traction on the peelable tab 4, at the level of its second longitudinal section 46 (or even if necessary at the level of its terminal section 48) forming a gripping member / traction.

During this traction, the peelable tab 4 gradually detaches from the circumference of the tin can 1 by crack propagation, by a phenomenon of cohesive or adhesive rupture (depending on the nature and composition of the fusible material used), from the second longitudinal section 46 then along the first longitudinal section 45.

Intercalary transverse portion and m sealing means

According to the invention, the peelable tab 4 further comprises an intermediate transverse portion 47, corresponding to the transition between the first longitudinal section 45 and the second longitudinal section 46.

This intermediate transverse portion 47 thus forms a sort of step or radial offset.

The intermediate transverse portion 47 thus deviates / diverges with respect to the metal cover 3 / metal box body 2 couple, from the first longitudinal section 45 to the second longitudinal section 46.

This intermediate transverse portion 47 still extends facing the upstream transverse border 4d1.

The intermediate transverse portion 47 has two opposite faces ( ):

- an inner face 471, facing and at a distance from the metal cover 3 / metal box body 2 couple, and

- An opposite outer face 472.

A transverse space E1 is thus provided between, on the one hand, the inner face 471 of said intermediate transverse portion 47 and, on the other hand, the pair metal cover 3 / metal box body 2.

The transverse space E1 is further delimited here by the upstream transverse border 4d1 of the peelable tab 4.

This transverse space E1 opens transversely, at the level of the two longitudinal edges 4a of the peelable tab 4.

Sealing means 6 are provided to close the transverse space E1.

The term "closing" advantageously means sealing against fluids. This tightness thus prevents circulation of fluids (air and liquid) through this transverse space E1, between the interior of the metal can 1 and the environment.

This circulation within the transverse space E1 is also called "transverse circulation", in a "vertical" direction (coaxial with the general axis 2', 3' of the metal tin can 1).

Still according to the invention, the sealing means 6 can also be provided to help close a longitudinal space E2 which is defined between the inner face 461 of the second longitudinal section 46 and the outer face 4532 of the upstream portion 453 of the first section longitudinal 45.

These sealing means 6 can be useful for optimizing the heat sealing of the peelable tab 4 on itself (between the second longitudinal section 46 and the first longitudinal section 45), in particular in the presence of a lack of support / pressure of heat sealing capable of generating this longitudinal space E2.

By “closing”, we again mean sealing against fluids. This tightness thus prevents circulation of fluids (air and liquid) through this longitudinal space E2, between the interior of the metal can 1 and the environment.

Such sealing means 6 can take different embodiments, described in relation to the figures below.

These embodiments can be implemented independently of each other, or in combination with each other.

According to one embodiment, the sealing means 6 are formed by a particular distribution of the fusible material which fills the transverse space E1.

For this purpose, as illustrated in the , the longitudinal tongue 4 advantageously has a particular contour: the upstream transverse edge 4d1 extends non-perpendicularly with respect to the longitudinal edges 4a.

This embodiment participates in optimizing the sealing of the transverse space E1.

Without being limited by any theory, this shape generates an increased local sealing pressure (due to a locally reduced support surface), in particular during the implementation of the support tool 10 ( ); the flow of fusible material is also guided by the upstream transverse edge 4d1 of the peelable tab 4, so that it penetrates the interstices and fills the transverse space E1.

Still without being limited by any theory, the transverse space E1 presents an increased length; the longer path increases the chance of an effective obturation.

In this sense, as illustrated in Figures 4 and 5, the upstream transverse edge 4d1 of the upstream portion 453 of the first longitudinal section 45 advantageously comprises at least one V-shaped portion.

By “V-shaped portion”, we advantageously mean:

- a convex V-shaped portion, the point of which (protruding) terminates the upstream transverse border 4d1 (figures 4A. and 4B.), or

- A concave V-shaped portion, the point of which (recessed) initiates the upstream transverse border 4d1 (FIGS. 4C. and 4D.).

Without being limiting, a concave V-shaped portion allows convergence of the flow of heat-sealing material towards the tip (as illustrated by the schematic arrows in FIGS. 4C. and 4D.), which makes it possible to optimize sealing.

Preferably, the upstream transverse border 4d1 comprises:

- a V-shaped portion (Figures 4A. or 4C.), advantageously extending over the entire width of the peelable tab 4, or

- two juxtaposed V-shaped portions (Figures 4B. or 4D.), juxtaposed over the width of the peelable tab 4.

The V-shaped portion advantageously has an angular dimension ranging from 30° to 90°.

According to an embodiment illustrated in Figures 6A., 6C. or 6D., the sealing means 6 are formed by at least one molding 63 provided at least in (across) the intermediate transverse portion 47.

Said at least one molding 63 consists of a convex molding on the side of the inner face 471 of the intermediate transverse portion 47 (projecting towards the couple metal cover 3 / metal box body 2).

The intermediate transverse portion 47 is advantageously cut by at least one molding 63, more preferably by at least two moldings 63, or even by at least three moldings 63.

Preferably, said at least one molding 63 intersects the intermediate transverse portion 47 at the level of the lower band 41 of the peelable tab 4 and of the upper band 42 of the peelable tab 4, so as to optimize the sealing of the space transverse E1 (top and bottom – on the side of each longitudinal border 4a).

For example, as shown in Figures 6C. and 6D, the intermediate transverse portion 47 is advantageously cut by two or three moldings 63.

This molding 63 thus advantageously extends, for a first part, in the first longitudinal section 45 and, for a second part, in the second longitudinal section 46.

The molding(s) 63 advantageously extend non-perpendicularly, also called “inclined”, relative to the longitudinal edges 4a of the peelable tab 4.

In this case, the peelable tab 4, and in particular the second longitudinal section 46, has several parallel moldings 63 which are distributed over its length/circumference.

The moldings 63 advantageously extend over the entire height of the peelable tab 4, from one longitudinal edge 4a to the other.

The parallel moldings 63 are preferably inclined relative to the two longitudinal edges 4a of the peelable tab 4.

Such moldings 63 have the advantage of closing off, or at least helping to close off, the transverse space E1, or even the longitudinal space E2.

The moldings 63 can have any other suitable shape, for example a straight line (FIGS. 6A. or 6C.), a V-shape (FIG. 6D.), a wavy/sinusoidal line (not shown), arranged juxtaposed or interspersed .

Moreover, in general, as illustrated in the , the peelable tab 4 (including its first longitudinal section 45) and the metal lid 3 / metal box body 2 pair possibly together define at least one chamber 7.

A filler seal 8 advantageously fills said at least one chamber 7, preferably at least over the length of the intermediate transverse portion 47.

This filler seal 8 provides an additional sealing/thermal bonding surface for the intermediate transverse portion 47, thus contributing to the sealing means 6 of the transverse space E1.

Preferably, the filler seal 8 also extends:

- Opposite the inner face 451 of the first longitudinal section 45 ( ) and or

- between the inner face 461 of the second longitudinal section 46 and the outer face 4532 of the upstream portion 453 of the first longitudinal section 45, forming an intermediate seal ( ).

Such a filler seal 8 still confers various advantages:

- The filler seal 8 provides an additional sealing/fusing surface for the peelable tab 4, and in particular the inner face 451 of the first longitudinal section 45;

- the filler seal 8 participates in the sealing of the metal tin can 1;

- the "spacer" filler joint 8 provides an additional sealing/thermal bonding surface between the second longitudinal section 46 and the upstream portion 453 of the first longitudinal section 45.

The "spacer" filler seal 8 is particularly useful for helping to ensure optimal sealing / heat sealing in the longitudinal space E2.

The filler joint 8 consists for example, without being limiting, of a polyamide hot glue.

According to yet another embodiment, not shown, the sealing means 6 comprise an additional heat-sealing material which is attached at least in the transverse space E1.

The additional heat-sealing material may be identical to, or different from, the heat-sealing material suitable for sealing the peelable tab 4.

This additional heat-sealing material is preferably added between the inner face 461 of the second longitudinal section 46 and the outer face 4532 of said upstream portion 453 of said first longitudinal section 45.

The additional heat-sealing material then also participates in ensuring optimal sealing / heat-sealing in the longitudinal space E2.

For this, preferably, the additional heat-sealing material is added:

- locally on the circumference of the metal cover 3 / metal box body 2 couple, or

- evenly around the circumference of the metal cover 3 / metal box body 2 pair or

- in a localized manner, between the inner face 461 of the second longitudinal section 46 and the outer face 4532 of said upstream portion 453 of said first longitudinal section 45.

According to yet another embodiment, illustrated by the , an adhesive strip 9 is attached to the longitudinal space E2, between the inner face 461 of the second longitudinal section 46 and the outer face 4532 of the upstream portion 453 of the first longitudinal section 45.

This adhesive strip 9 could also extend into the transverse space E1.

Such an adhesive strip 9 contributes to ensuring optimal assembly in the longitudinal space E2, or even to participate in closing the transverse space E1.

Such an adhesive strip 9 also allows assembly of the peelable tab 4 on itself, in an easy manner (establishing contact with low/moderate pressure).

Manufacturing process

The present invention also relates to the process for the manufacture of a metal tin can 1 according to the invention.

This manufacturing process includes:

(i) a step of supplying the following parts:

- the aforementioned canister body 2, comprising a side wall 21, a second end 212 of which delimits an access opening 23,

- the metal cover 3, adapted to close this access opening 23, and

- the peelable tab 4,

(ii) a step of closing the metal can 1 during which:

- the metal cover 3 is positioned at the level of the access opening 23 of the metal box body 2, and

- the metal lid 3 is sealed at the level of the access opening 23 of the metal box body 2, by heat-sealing the peelable tab 4 on the circumference of the peripheral skirt 31 of the metal lid 3 and of the second end 212 of the side wall 21 of the can body 2.

As previously developed in relation to the , the peelable tab 4 is arranged to form the first longitudinal section 45 and the second longitudinal section 46, connected by the intermediate transverse portion 47.

The thermal bonding is advantageously activated by combined actions of heat and pressure, for a suitable time.

The heating is advantageously carried out from the outer face 4c of the peelable tab 4, to generate the thermal bonding by means of a phenomenon of thermal conduction or induction.

Advantageously, the heat sealing of the peelable tab 4 can be obtained by means of at least one support tool 10, advantageously a support wheel 10.

Said at least one support tool 10 is advantageously intended to travel around the circumference of the peelable tab 4, along its outer face 4c.

The heat-sealing material then advantageously forms a bead of heat-sealing material, also called "a front" or "a wave" or "an accumulation" of heat-sealing material, which progresses upstream of this support tool 10.

Preferably and as illustrated on the , the peelable tab 4 is heat-sealed progressing along its length:

- along the first longitudinal section 45, from its upstream transverse edge 4d1, then

- along the second longitudinal section 46, so that it covers the upstream portion 453 of the first longitudinal section 45.

According to the invention, the method according to the invention further comprises a sealing step which is designed to close off the transverse space E1, or even also the longitudinal space E2.

In practice, the sealing step can be chosen from among different sealing steps, which can be taken alternately or in combination.

According to an embodiment described in relation to the , the sealing step relies on a step of supplying a peelable tab 4 which comprises an upstream transverse edge 4d1 extending non-perpendicularly with respect to the longitudinal edges 4a.

Without being limited by any theory, this shape generates an increased local sealing pressure (due to a locally reduced support surface), in particular during the implementation of the support tool 10 ( ).

The bead of fusible material, traveling upstream of the bearing tool 10, is guided by the upstream transverse edge 4d1 of the peelable tab 4, so that it penetrates the interstices and fills the transverse space E1.

According to an embodiment described in relation to the , the sealing step relies on a molding step of the peelable tab 4 to form at least one molding 63 formed at least in the intermediate transverse portion 47.

In this case, as schematically illustrated in the , the support tool 10 advantageously comprises at least one rib 101 which is adapted to form the complementary moldings 63 as it travels along the outer face 4c of the peelable tab 4.

According to yet another embodiment, not shown, the sealing step relies on a step of applying additional fusible material, advantageously localized or homogeneous.

This additional iron-on material can be brought back:

- on the metal lid 3 / metal box body 2 couple, just upstream of the upstream transverse edge 4d1 of the peelable tab 4, to participate in closing the transverse space E1 by flow,

- even between the inner face 461 of the second longitudinal section 46 and the outer face 4532 of said upstream portion 453 of said first longitudinal section 45, to participate in closing the longitudinal space E2 by creep.

Of course, various other modifications may be made to the invention within the scope of the appended claims.

Claims (15)

Tin can including:
- a metal box body (2) comprising a side wall (21) of which a first end (211) is connected to a bottom (22) and of which a second end (212) delimits an access opening (23),
- a metal cover (3) adapted to close said access opening (23), which metal cover (3) comprises a peripheral skirt (31) which comprises an interlocking strip (311) adapted to cooperate by interlocking with said second end (212) of the side wall (21), and
- a peelable tab (4) which is sealed, by a heat-sealing material, on the circumference of the peripheral skirt (31) of the metal cover (3) and of the second end (212) of the side wall (21) of the body of the metal box (2),
characterized in that the peelable tab (4) comprises:
- a first longitudinal section (45) of which an inner face (451) is sealed with the metal cover (3)/metal box body (2) couple,
- a second longitudinal section (46) covering an upstream portion (453) of said first longitudinal section (45), the inner face (461) of said second longitudinal section (46) being sealed with an outer face (4532) of said upstream portion ( 453) of said first longitudinal section (45),
which peelable tab (4) comprises an intermediate transverse portion (47), corresponding to the transition between said first longitudinal section (45) and said second longitudinal section (46),
and in that said metal tin can (1) comprises sealing means (6) which are arranged to close off a transverse space (E1) arranged between the inner face (471) of the said intermediate transverse portion (47) and the metal cover (3) / metal box body (2) pair. Metal tin can, according to claim 1, characterized in that the peelable tab (4) comprises two longitudinal edges (4a), parallel,
in that the upstream portion (453) of said first longitudinal section (45) comprises a transverse edge (4d1) extending non-perpendicular to said longitudinal edges (4a), and
in that the sealing means (6) are formed by the fusible material which fills the transverse space (E1). Metal tin can, according to claim 2, characterized in that the transverse edge (4d1) of the upstream portion (453) of the said first longitudinal section (45) comprises at least one V-shaped portion, preferably one V-shaped portion or two juxtaposed V-shaped portions. Metal tin can, according to any one of Claims 1 to 3, characterized in that the sealing means (6) are formed by at least one molding (63), preferably at least two or three moldings (63) , provided at least in the intermediate transverse portion (47),
which at least one molding (63) consists of a convex molding (63) on the side of the inner face (4c) of the peelable tab (4). Metal tin can, according to Claim 4, characterized in that the said intermediate transverse portion (47) comprises several parallel moldings (63), distributed over the circumference of the said peelable tab (4),
which parallel moldings (63) are preferably inclined with respect to the two longitudinal edges (4a). Metal tin can, according to any one of Claims 1 to 5, characterized in that the sealing means (6) comprise an additional heat-sealing material applied at least in the transverse space (E1),
which additional heat-sealing material is preferably added between the inner face (461) of the second longitudinal section (46) and the outer face (4532) of said upstream portion (453) of said first longitudinal section (45). Metal tin can, according to claim 6, characterized in that the additional heat-sealing material is applied in a localized manner, or in a homogeneous manner on the circumference of the metal lid (3)/metal can body (2) pair. Metal tin can, according to any one of Claims 1 to 7, characterized in that it comprises an adhesive strip (9) which is attached between the inner face (461) of the second longitudinal section (46) and the outer face ( 4532) of said upstream portion (453) of said first longitudinal section (45), or even in the transverse space (E1). Metal tin can, according to any one of Claims 1 to 8, characterized in that the peelable tab (4) and the metal lid (3)/metal can body (2) pair together define at least one chamber (7 ),
and in that a filler seal (8) fills said at least one chamber (7) at least along the length of the intermediate transverse portion (47). Metal tin can, according to claim 9, characterized in that the filler seal (8) further extends:
- Facing the inner face (451) of the first longitudinal section (45) and/or
- Between the inner face (461) of the second longitudinal section (46) and the outer face (4532) of said upstream portion (453) of said first longitudinal section (45). A process for manufacturing a metal can according to any of claims 1 to 10, which manufacturing process comprises:
(i) a step of supplying the following parts:
- the metal box body (2) comprising a side wall (21) of which a second end (212) delimits an access opening (23),
- the metal cover (3), adapted to close said access opening (23), and
- the peelable tab (4),
(ii) a step of closing said metal can (1) during which:
- said metal cover (3) is positioned at said access opening (23) of the metal box body (2), and
- the metal lid (3) is sealed at the level of the access opening (23) of the metal box body (2), by heat-sealing said peelable tab (4) on the circumference of the peripheral skirt (31) of the metal cover (3) and the second end (212) of the side wall (21) of the metal box body (2),
which peelable tab (4) is arranged to include:
- a first longitudinal section (45) of which an inner face (451) is formed opposite and on the circumference of the metal lid (3)/metal box body (2) pair,
- a second longitudinal section (46) covering an upstream portion (453) of said first longitudinal section (45), the inner face (461) of said second longitudinal section (46) being sealed with an outer face (4532) of said upstream portion ( 453) of said first longitudinal section (45), and
- an intermediate transverse portion (47), corresponding to the transition between said first longitudinal section (45) and said second longitudinal section (46),
which method further comprises a sealing step which is designed to close off the transverse space (E1) made between the inner face (471) of the said intermediate transverse portion (47) and the metal cover (3)/metal can body pair (2). Method according to Claim 11, in combination with Claim 2, characterized in that the step of sealing is a step of supplying a peelable tab (4) whose upstream portion (453) of the first longitudinal section (45) comprises a transverse border (4d1) extending non-perpendicular to said longitudinal borders (4a). Method according to Claim 11, in combination with Claim 4, characterized in that the step of sealing is a step of molding the peelable tab (4) to form at least one molding (63) provided at least in the portion transverse spacer (47). Method according to claim 11, in combination with claim 9, characterized in that the step of sealing is a step of filling a longitudinal chamber (7) with the filler seal (8). Method according to Claim 11, in combination with Claim 6, characterized in that the step of sealing is a step of applying an additional heat-adhesive material, advantageously localized or homogeneous.