FR3146132A1 - Metal packaging, comprising a can body on which a peelable membrane is sealed - Google Patents

Abstract

The present invention relates to a metal packaging, comprising a can body (2) on which a peelable membrane (3) is sealed. The side wall (21) of the can body (2) is terminated by a free edge (215) which comprises a roll (216) oriented towards said outer face (212). And the peelable membrane (3), in the form of a cup, comprises a closing wall (31), closing an access opening (A), and a peripheral strip (32), sealed on a receiving strip (211a). And the roll (216) has a height dimension (R) ranging from 0.5 to 1.6 mm; and a longitudinal dimension (C) between the free edge (321) of the peripheral strip (32) and the longitudinal top (2161) of the roll (216) is from 0 to 1.5 mm. Figure for abstract: 3

Description

Metal packaging, comprising a can body on which a peelable membrane is sealed Technical field of the invention

The present invention relates to the technical field of metal packaging, comprising a can body on which a peelable membrane is sealed.

State of the art

Metal packaging is commonly used in the form of metal cans for packaging food products. Such metal packaging can also be used for packaging other industrial products, such as paints.

Some metal packaging includes a lid formed by a metal ring on which a peelable membrane is sealed by heat sealing. Such a lid structure allows easy opening, directly by hand, without requiring a tool or accessory.

However, the use of a metal ring is not optimal for various reasons, in particular on material consumption.

To overcome these drawbacks, there are metal packagings in which the peelable membrane is sealed directly onto the body of the can.

But, again, current “direct sealing” solutions are not entirely satisfactory.

The cans in question are in fact taller in order to introduce and seal the peelable membrane, leading to increased material consumption at the can body level and a reduction in the useful volume of said metal packaging.

Presentation of the invention

In order to overcome the aforementioned drawback of the state of the art, the present invention proposes a metal packaging, comprising a can body (also called “packaging body”) on which a peelable membrane is sealed.

The box body has a side wall, defining a longitudinal axis, which has an inner face and an outer face.

The side wall ends with a free edge which delimits an access opening and which has a roll oriented towards said external face, which roll has a longitudinal peak.

The inner face comprises, on the side of said free edge, a receiving strip on which said peelable membrane is intended to be sealed.

The peelable, cup-shaped membrane comprises:

- a closing wall, closing said access opening, and

- a peripheral strip, sealed on said receiving strip, comprising a free edge.

And according to the invention, said roll has a height dimension ranging from 0.5 to 1.6 mm; the longitudinal dimension between said free edge of the peripheral strip and said longitudinal top of the roll is from 0 to 1.5 mm.

According to the invention, such a structure offers various advantages, in particular an optimization of the consumption of metallic material and an increase in the useful volume.

Other non-limiting and advantageous characteristics of the product according to the invention, taken individually or in all technically possible combinations, are as follows:

- said roll has a height dimension ranging from 0.7 to 1.5 mm;

- the longitudinal dimension between said free edge of the peripheral strip and said longitudinal top of the roll is 0 to 0.8 mm;

- the roll has a circular or oblong section; for an oblong section, the roll advantageously has a height dimension, parallel to the longitudinal axis, ranging from 0.5 to 1 mm, and a width dimension, perpendicular to the longitudinal axis, ranging from 1 to 2 mm, preferably from 1 to 1.5 mm;

- the longitudinal dimension between the closure wall and the top of the roll is 2.5 to 5 mm, preferably 3 to 4.5 mm;

- the peelable membrane comprises a tab which extends the peripheral strip; the tab is advantageously folded inwards, on the sealing wall, or outwards, overlapping the roll; the tab advantageously has a width ranging from 15 to 38 mm, preferably from 15 to 30 mm, advantageously decreasing from the peripheral strip or of constant width, to avoid the risk of tearing;

- the receiving strip has an angle equal to or greater than 0°, and less than 90°, relative to a longitudinal axis of said side wall, which angle is for example chosen from 0°, from 40 to 60°;

- said peelable membrane is made of a pre-formable aluminum base material, having a thickness ranging from 50 to 90 µm, preferably 60 to 70 µm, useful for effective peeling;

- said peelable membrane comprises an aluminum layer which is covered with at least one sealing layer;

- the can body comprises either a crimped side wall and a bottom wall, to form a three-piece can, or a one-piece side wall and a bottom wall, for a two-piece can; preferably, the can body is made in two pieces, with a rolled/welded side wall;

- the side wall has a thickness of 0.13 to 0.24 mm for a three-piece steel box, 0.13 to 0.24 mm for a two-piece steel box, and 0.17 to 0.25 mm for a two-piece aluminum box.

The present invention also relates to the method for manufacturing a metal packaging according to the invention, which comprises:

- a step of supplying the box body and a step of supplying the peelable membrane, then

- a direct sealing step, of the peelable membrane on the body of the can.

According to other advantageous characteristics:

- during the supply stage, the peelable membrane is shaped, for example by stamping, before being placed in the body of the box;

- the sealing material is applied to the body of the box, where applicable including on the weld by applying the so-called heat-sealing re-seal varnish,

- said direct sealing step is carried out by heating tooling chosen from a mandrel, a segment, a wheel.

Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

Detailed description of the invention

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

is a general and sectional view of a metal packaging according to the invention;

is a partial and enlarged view of the metal packaging according to the , illustrating in more detail the free edge of its side wall and the tab of the peelable membrane folded inwards;

is a partial and enlarged view of the metal packaging according to the , illustrating in more detail the free edge of its side wall in the form of a circular roll;

is a partial and enlarged view of the metal packaging according to the , illustrating in more detail the free edge of its side wall in the shape of an oblong roll;

is a partial and enlarged view of another metal packaging according to the invention, the receiving strip of which is inclined relative to the longitudinal axis;

is a partial and enlarged view of another metal packaging according to the invention, illustrating the tab of the peelable membrane folded outwards;

is a top view of an isolated peelable membrane.

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 present invention thus relates to a metal packaging 1, comprising a box body 2 on which a peelable membrane 3 is sealed.

Such metal packaging 1 is for example intended to contain sterilized or pasteurized foods, dry products, liquids, non-food, non-sterilizable products.

Box body

The box body 2 comprises a side wall 21, defining a longitudinal axis 2’.

The side wall 21, advantageously a ferrule or cylinder, has a cross section (along a plane perpendicular to the longitudinal axis 2') which is advantageously circular, oval or quadrilateral (square or rectangular).

This side wall 21 has two opposite faces:

- an inner face 211, intended to be oriented towards the storage volume V and to come into contact with the packaged product, and

- an external face 212, opposite.

The side wall 21 ends with a free edge 215 which delimits an access opening A.

The free edge 215 comprises a roll 216 which is oriented towards the outer face 212 of the side wall 21.

This 216 roll wraps around a 216’ center.

The roll 216 notably has a longitudinal peak 2161.

By “longitudinal vertex 2161”, we also advantageously mean the line of the roll 216 defined by a straight line which is tangent to said roll 216 and which extends perpendicular to a generatrix 211a’ of a receiving strip 211a on which the peelable membrane 3 is intended to be sealed.

This longitudinal peak 2161 advantageously consists of a line whose shape corresponds to the section of the side wall 21, while having a section greater in dimension.

According to the invention, the rolled part 216 has a height dimension R (advantageously measured parallel to the longitudinal axis 2’) ranging from 0.5 to 1.6 mm.

More preferably, the rolled 216 has a height dimension R ranging from 0.7 to 1.5 mm.

Generally speaking, the 216 roll advantageously has a section chosen from:

- a circular section ( ), Or

- an oblong section ( ).

For a circular section, the height dimension R corresponds to the diameter of the rolled section 216.

For an oblong section, the 216 roll advantageously has the following dimensions:

- a height dimension H, parallel to the longitudinal axis 2’, ranging from 0.5 to 1 mm, and

- a width dimension L, perpendicular to the longitudinal axis 2’, ranging from 1 to 2 mm, preferably from 1 to 1.5 mm.

Preferably, the major axis of the oblong roll 216 extends perpendicular to the longitudinal axis 2’.

The inner face 211 comprises, on the side of the free edge 215, a receiving strip 211a on which the peelable membrane 3 is intended to be sealed.

As mentioned previously, this reception band 211a is advantageously defined by a generator 211a’.

This receiving strip 211a advantageously has an angle equal to or greater than 0°, and less than 90°, relative to the longitudinal axis 2’ of said side wall 21. This receiving strip 211a has, for example, an angle ranging from 0° to 60° relative to the longitudinal axis 2’ of said side wall 21.

This angle is advantageously measured between the generator 211a’ and the longitudinal axis 2’ of said side wall 21.

Generally speaking, the angle of the receiving strip 211a, relative to the longitudinal axis 2’, is for example chosen from:

- 0°, so that the receiving strip 211a is parallel to the longitudinal axis 2’ (figures 1 to 4 in particular), or

- from 40° to 60° so that the receiving strip 211a diverges from the longitudinal axis 2', advantageously of generally truncated cone shape ( ).

Preferably and generally, the receiving strip 211a has a width dimension ranging from 1.5 to 4 mm, preferably from 2.5 to 4 mm.

Again generally, the box body 2 comprises:

- a side wall 21, and a bottom wall (not shown) attached by crimping, to form a three-piece box,

Or

- a side wall 21 and a bottom wall (not shown) in one piece, for a two-piece box.

More preferably, in a conventional manner, the box body 2 is made in two pieces, with a rolled/welded side wall 21.

In such a two-piece box, the side wall 21 advantageously comprises a second free edge 218, intended to be secured to the bottom wall by crimping.

Still generally, the side wall 21 advantageously has a thickness chosen from:

- 0.13 to 0.24 mm for a three-piece steel box,

- 0.13 to 0.24 mm for a two-piece steel box, and

- 0.17 to 0.25 mm for a two-piece aluminum box.

Peelable membrane

The peelable membrane 3 has a cup shape. It comprises:

- a closing wall 31, closing the access opening A, and

- a peripheral strip 32, sealed on the receiving strip 211a of the box body 2.

The peripheral strip 32 has two edges:

- a first edge 321, also called “free edge”, opposite the closure wall 31, and

- a second edge 322, connected to the closing wall 31.

According to the invention, a longitudinal dimension C (advantageously measured on the generator 211a' defined by the receiving strip 211a) between the free edge 321 of the peripheral strip 32 and the longitudinal peak 2161 of the roll 216 is from 0 to 1.5 mm ( ).

More preferably, this longitudinal dimension C between the free edge 321 of the peripheral strip 32 and the longitudinal peak 2161 of the roll 216 is from 0 to 0.8 mm.

Furthermore, the longitudinal dimension F (advantageously measured on the generatrix 211a' defined by the receiving strip 211a) between the closing wall 31 (or at the level of the second edge 322 of the peripheral strip 32) and the longitudinal top 2161 of the roll 216 is advantageously 2.5 to 5 mm, preferably 3 to 4.5 mm ( ).

Likewise, the free edge 321 of the peripheral strip 32 advantageously extends in a transverse plane passing, at least approximately, through the center 216' of the roll 216.

Generally speaking, the peelable membrane 3 advantageously comprises a tab 35 which extends the peripheral strip 32, advantageously from the free edge 321.

This tab 35 is useful for peeling the peelable membrane 3, when opening the metal packaging 1.

In this case, the tab 35 is advantageously folded:

- inwards, on the closing wall 31 and extending in front of the peripheral strip 32 ( in particular), or

- outwards, overlapping the roll 216 ( ) and extending in front of the outer face 212 of the side wall 21.

Generally, as shown in the , the tab 35 advantageously has a width dimension G ranging from 15 to 38 mm.

The tab 35 may have a rectangular shape (with a constant width dimension G).

More preferably, this tab 35 has a width decreasing from the peripheral strip 32 (more preferably from the free edge 321), to avoid the risk of tearing.

In this case, the tab 35 advantageously comprises two parts:

- an upstream part 351, comprising two concave lateral edges, and

- a downstream part 352, in an arc of a circle.

The width dimension of the upstream part 351 is greater than the width dimension of the downstream part 352.

This shape is useful to avoid tearing when peeling and to fold down without making creases.

Generally speaking, the peelable membrane 3 is advantageously made from a pre-formable aluminum base material, having a thickness ranging from 50 to 90 µm, preferably 60 to 70 µm.

Again generally, the peelable membrane 3 optionally comprises an aluminum layer which is covered with at least one sealing layer (for example in polypropylene), advantageously two heat-sealing layers.

Still generally, the peelable membrane 3 is advantageously chosen from among the classic peelable membranes 3 per se.

This peelable membrane 3 has two opposing surfaces:

- an external surface, intended to be oriented towards the outside of the box body 2,

- an inner surface, intended to be oriented towards the inside of the box body 2 and designed to be sealed on the receiving strip 211a.

Traditionally, the peelable membrane 3 comprises several layers:

- a base layer, also called a “barrier layer”, upper, made of a resistant and flexible material, for example aluminum, and

- a lower sealing layer, particularly adapted to ensure sealing with the receiving strip 211a.

Heat sealing material for can body

A heat-sealing material is advantageously distributed at least on the receiving strip 211a of the can body 2, including on the weld in the case of a three-piece can (application of a so-called heat-sealing re-champi varnish on the weld).

“Heat sealing material” means a material capable of being activated to provide a sealing (or bonding) function when subjected to heating (e.g. 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 polypropylene dispersion).

Manufacturing process

In practice, the method of manufacturing the metal packaging 1 according to the invention comprises:

- a step of supplying the box body 2 and a step of supplying the peelable membrane 3, then

- a “direct” sealing step of the peelable membrane 3 on the box body 2.

During the supply step, the peelable membrane 3 is advantageously shaped (a sealing wall 31 and a peripheral strip 32), for example by stamping, before being placed in the box body 2.

The peelable membrane 3 is then in the form of a pre-stamped cup. This prior shaping is useful for avoiding folds at the peripheral strip 32.

Furthermore, a sealing material is advantageously added to the box body 2, where appropriate including on the weld by application of the so-called heat-sealing resurfacing varnish.

For example, the sealing step is advantageously carried out by a heat sealing operation.

Preferably, the sealing step is carried out by any suitable heating tool, for example mandrels, segments, wheels.

The appropriate tools can be:

- a direct heating emitter (e.g. heating mandrel, heating segments, heating wheels), or

- an indirect heating emitter (e.g. induction heating).

In the case of a three-piece box, the filling is advantageously carried out after the sealing of the peelable membrane 3 on the box body 2; this peelable membrane 3 then forms the lower bottom of the box body 2.

A bottom wall (not shown) is then crimped at the level of the second free edge 218 of the side wall 21 which is located opposite the roll 216.

Conversely, in the case of a two-piece box, the filling is advantageously carried out before the sealing of the peelable membrane 3 on the box body 2. In other words, the peelable membrane 3 is attached to the box body 2 after it has been filled.

Advantage of the invention

The metal packaging 1 according to the invention has the advantage of presenting an optimization of metal consumption, in particular due to the combination of:

- the structure of the rolled 216, and

- the longitudinal dimension C between the free edge 321 of the peripheral strip 32 and the longitudinal peak 2161 of the roll 216.

This solution has the advantage of allowing an interior volume which is increased, with an equal quantity of metal.

Another advantage of the invention is to provide a metal packaging which is dimensionally balanced (approximately the same diameter at the top and bottom).

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

Claims (14)

Metal packaging, comprising a can body (2) on which a peelable membrane (3) is sealed,
which box body (2) comprises a side wall (21), defining a longitudinal axis (2') which has an inner face (211) and an outer face (212),
which side wall (21) is terminated by a free edge (215) which delimits an access opening (A) and which comprises a roll (216) oriented towards said external face (212), which roll (216) has a longitudinal apex (2161),
which inner face (211) comprises, on the side of said free edge (215), a receiving strip (211a) on which said peelable membrane (3) is intended to be sealed,
which peelable membrane (3), in the shape of a cup, comprises:
- a closing wall (31), closing said access opening (A), and
- a peripheral strip (32), sealed on said receiving strip (211a), comprising a free edge (321),
characterized in that said roll (216) has a height dimension (R) ranging from 0.5 to 1.6 mm, and
in that a longitudinal dimension (C) between said free edge (321) of the peripheral strip (32) and said longitudinal peak (2161) of the roll (216) is from 0 to 1.5 mm. Metal packaging according to claim 1, characterized in that said roll (216) has a height dimension (R) ranging from 0.7 to 1.5 mm. Metal packaging according to any one of claims 1 or 2, characterized in that the longitudinal dimension (C) between said free edge (321) of the peripheral strip (32) and said longitudinal top (2161) of the roll (216) is 0 to 0.8 mm. Metal packaging according to any one of claims 1 to 3, characterized in that the roll (216) has a circular or oblong section. Metal packaging according to claim 4, characterized in that, for an oblong section, the roll (216) has:
- a height dimension (H), parallel to the longitudinal axis (2'), ranging from 0.5 to 1 mm, and
- a width dimension (L), perpendicular to the longitudinal axis (2'), ranging from 1 to 2 mm. Metal packaging according to any one of claims 1 to 5, characterized in that the longitudinal dimension (F) between the closing wall (31) and the longitudinal top (2161) of the roll (216) is 2.5 to 5 mm. Metal packaging according to any one of claims 1 to 6, characterized in that the peelable membrane (3) comprises a tab (35) which extends the peripheral strip (32). Metal packaging according to claim 7, characterized in that the tab (35) is folded:
- inwards, on the sealing wall (31), or
- outwards, overlapping the roll (216). Metal packaging according to any one of claims 7 or 8, characterized in that the tab (35) has a width ranging from 15 to 38 mm, advantageously decreasing or of constant width from the peripheral strip (32). Metal packaging according to any one of claims 1 to 9, characterized in that the receiving strip (211a) has an angle equal to or greater than 0°, and less than 90°, relative to said longitudinal axis (2') of said side wall (21),
which angle is for example chosen from 0° or from 40 to 60°. Method for manufacturing a metal packaging according to any one of claims 1 to 10, characterized in that it comprises:
- a step of providing the box body (2) and a step of providing the peelable membrane (3), then
- a direct sealing step of the peelable membrane (3) on the can body (2). Method according to claim 11, characterized in that, during the supply step, the peelable membrane (3) is shaped, for example by stamping, before being placed in the box body (2). Method according to any one of claims 11 or 12, characterized in that a sealing material is applied to the box body (2), where appropriate including on the weld by application of the so-called heat-sealing resurfacing varnish. Method according to any one of claims 11 to 13, characterized in that said direct sealing step is carried out by a heating tool chosen from a mandrel, a segment, a wheel.