EP1780135B1 - Envelope of the type consisting of a heat shrinkable plastic sleeve for packaging at least one object - Google Patents

Description

The present invention relates to the packaging of objects and, in particular, the packaging of consumer products such as food, chemical, cosmetic, or pharmaceutical products, which generally require consumer or user information, or other purely commercial information.

More specifically, the invention relates to an envelope for packaging at least one object, of the type consisting of a heat shrinkable plastic sleeve adapted to closely surround at least a part of the object or group of objects, said sleeve including the possibility of integrating an information carrier.

BACKGROUND OF THE INVENTION

The document EP-A-0 670 807 of the Applicant illustrates an envelope of the aforementioned type having a complementary flap which defines a tear-detachable flap at two parallel lines extending along generatrices of the sleeve. This complementary flap forms with the opposite side of the main portion of the sleeve a pocket which is intended to contain an explanatory note consisting of one or a few leaflets.

Alternatively, the document EP-A-0 775 643 of the applicant illustrates another envelope with complementary flap, wherein the flap is tear-detachable at two parallel lines extending in a circumferential direction of the sleeve by pulling an associated end tab. Here again, the complementary flap delimits with the main portion of the sleeve a pocket into which is inserted a notice that is accessed after detaching the flap.

The disadvantage of the solutions illustrated in the aforementioned documents lies essentially in the manual insertion of the notices associated with the envelopes, which insertion implies the presence of a specialized workforce on the spot, which slows the production rates and represents a significant part of the cost of manufacturing the envelopes.

To overcome these disadvantages, it has also been proposed a solution in which an adhesive strip extends along a generatrix of the sleeve on the outer face of the main portion thereof, said strip serving to hold a flat object in the formed pocket. by the complementary flap, such that said object is trapped behind the detachable flap and recoverable once said detached flap, as described in the document EP-A-1,294,614 of the plaintiff.

The aforementioned document is satisfactory when it comes to enveloping objects of dimensions corresponding to the usual dimensions of cosmetic or pharmaceutical products, with diameters of 5 cm or more. However, in the case of objects of smaller diameter, and whose shape is not necessarily cylindrical, it becomes difficult to organize a pocket containing a record or booklet because of the limited space available. In addition, we can not miniaturize the booklets or booklets with complete freedom, since most countries regulate the minimum size of the information printouts, including the legal information of consumers, to ensure sufficient legibility of this information.

It should be noted that, in all the aforementioned documents of the applicant, the complementary flap, which extends the main portion of the sleeve, has the function of defining a pocket in which is inserted a notice, so that said flap should not adhere the main portion of the sleeve over the entire area concerned, otherwise there would be no cover, so that the adhesion is always limited to two parallel generatrices defining the complementary flap defining a detachable flap.

A document showing the use of a strip with two walls and a printing pattern is DE-U-20 2004 000 865 .

OBJECT OF THE INVENTION

The object of the invention is to improve the envelopes of the aforementioned type by designing an arrangement making it possible to present a large area of information, even if the objects concerned are of small diameter, while preserving a minimum size for the readability of these informations.

GENERAL DEFINITION OF THE INVENTION

The aforementioned technical problem is solved according to the invention by means of an envelope intended for the packaging of at least one object, of the type constituted by a shrinkable plastic sleeve capable of closely surrounding at least a part of the object or of the group of objects, envelope in which the sleeve is formed by the superposition of at least two walls, which are joined together by a detachment gluing means generally relating to the entire surface of said envelope, said walls having substantially identical shrinkage characteristics to allow uniform shrinkage of the sleeve over the object or group of objects, and the outermost wall of the sleeve further having, throughout the thickness thereof at least one cutout at least partially defining a detachable circumferential band, said circumferential band being printed to present a print pattern appearing on each side thereof, the one or more other walls also having printed patterns, particularly behind the detachable circumferential band so that the corresponding printed pattern appears after detaching from said detachable circumferential band.

Thus, as soon as the user has detached the detachable circumferential band, he can read the information appearing on each side of said circumferential band, thus by examining the front and the back thereof, and this over a length corresponding substantially to the circumference of the object in the case of a cylindrical object, with the further possibility read the information that appears after detachment of the detachable circumferential band, thus with optimum availability over the entire outer surface of the remaining envelope portion on the object or group of objects concerned.

In an advantageous embodiment, the wall further outside the sleeve present, along a generatrix, a tear strip delimited by two parallel lines of pits or the like, and whose removal, in particular by means of a gripping tab, allows the subsequent detachment of the detachable circumferential band.

It will then be possible, in combination with or in replacement of the preceding feature, that the outermost wall of the sleeve has a cutout defining a gripping tongue at the end of the detachable circumferential strip. In particular, it may be provided, behind the gripping tongue, an area of lower resistance to peelability for the release of said tongue, or alternatively a reinforcing strip arranged along a generatrix of the sleeve.

The envelope may comprise two parallel circumferential cuts delimiting an intermediate circumferential band.

Alternatively, a single cutout may be provided in the upper part (or low) of the sleeve, the other edge of the circumferential band thus defined being constituted by the upper free edge (or lower) of the cut wall.

In another embodiment, there will be provided a substantially axial cut over the entire height of the sleeve, the edges of the circumferential band thus defined being constituted by the upper and lower free edges of the cut wall.

Advantageously, the detachable circumferential band includes an opacity means present in the mass or added to the surface, ensuring the readability of the printing patterns appearing on each side of said circumferential band.

It may also be provided that the circumferential band detachable has an embossing.

More preferably, the constituent walls of the sleeve are superimposed either independently or by folding (s) of the same wall, with the interposition of a detachable bonding means.

The release bonding means may be peelable or repositionable as appropriate.

The release bonding means may be in the form of a layer of adhesive, or a polymeric binder used during the coextrusion of the films constituting the walls, or an electrical polarization of the surfaces of the walls facing each other. inversion of the electrostatic field.

More preferably, the constituent walls of the sleeve are made from plastic films which are all either mono-oriented transversely or mono-oriented longitudinally. In particular, the films constituting the walls have essentially identical necking curves and softening points, said films being able to differ from each other by the material and / or the color and / or the thickness and / or the tactile aspect.

Other features and advantages of the invention will emerge more clearly in the light of the following description and the accompanying drawings, relating to a particular embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 illustre en perpective un contenant emballé avec une enveloppe selon l'invention, ladite enveloppe incluant une bande circonférentielle intermédiaire imprimée qui est détachable, en l'espèce en utilisant une bande d'arrachage axiale associée ;
• les figures 2 et 3 illustrent la séparation progressive des éléments détachables, avec respectivement en figure 2 la bande d'arrachage axiale, puis en figure 3 la bande circonférentielle détachable, permettant alors une lisibilité optimale des informations imprimées ;
• la figure 4 est une vue en plan de la face externe développée de l'enveloppe précitée, avant la configuration de l'enveloppe sous forme de manchon ;
• la figure 5 est une coupe selon la ligne V-V de la figure 4, permettant de mieux distinguer la découpe à mi-chair définissant une bande circonférentielle intermédiaire détachable ;
• les figures 6A et 6B sont des coupes selon la ligne VI-VI de la figure 4, illustrant des variantes à superposition de parois respectivement selon un mode indépendant et selon un mode plié avec interposition d'un moyen de collage à détachement ;
• les figures 7 et 8 sont des vues en perspective analogues à celles des figures 1 à 3, illustrant une variante de l'enveloppe précédente dont la bande circonférentielle intermédiaire détachable présente une languette de préhension ;
• la figure 9 est une vue en plan analogue à celle de la figure 4 illustrant à plat l'enveloppe des figures 7 et 8 ;
• la figure 10 est une vue en coupe selon la ligne X-X de la figure 9 ;
• les figures 11A et 11B sont des coupes selon la ligne XI-XI de la figure 9 illustrant deux variantes de superposition comme aux figures 6A et 6B précédentes ;
• les figures 12A et 12B sont des vues en coupe analogues à celles des figures 11A et 11B, illustrant encore d'autres variantes dans lesquelles le manchon est constitué par la superposition de trois parois solidarisées entre elles par un moyen de collage à détachement ;
• les figures 13 à 15 sont des vues en perspective illustrant encore d'autres variantes à découpe unique, avec une découpe circonférentielle haute (figure 13) ou basse (figure 14), ou une découpe essentiellement axiale (figure 15), la bande circonférentielle détachable ayant dans ce dernier cas la même hauteur que le manchon.

Reference will be made to the figures of the accompanying drawings, in which:

• the figure 1 illustrates in perspective a container packaged with an envelope according to the invention, said envelope including a printed intermediate circumferential band which is detachable, in this case using an associated axial tear strip;
• the Figures 2 and 3 illustrate the separation progressive detachable elements, with respectively figure 2 the axial tear strip, then figure 3 the detachable circumferential band, thus allowing optimum readability of the printed information;
• the figure 4 is a plan view of the developed outer face of the aforementioned envelope, before the configuration of the envelope in the form of a sleeve;
• the figure 5 is a section along line VV of the figure 4 , making it possible to better distinguish the half-flesh cut defining a detachable intermediate circumferential band;
• the Figures 6A and 6B are cuts along line VI-VI of the figure 4 , illustrating wall-superimposed variants respectively in an independent mode and in a folded mode with the interposition of a detaching gluing means;
• the Figures 7 and 8 are perspective views similar to those of Figures 1 to 3 , illustrating a variant of the previous envelope whose detachable intermediate circumferential band has a gripping tab;
• the figure 9 is a plan view similar to that of the figure 4 illustrating the envelope of Figures 7 and 8 ;
• the figure 10 is a sectional view along line XX of the figure 9 ;
• the Figures 11A and 11B are cuts along line XI-XI of the figure 9 illustrating two superimposition variants such as Figures 6A and 6B previous;
• the Figures 12A and 12B are sectional views similar to those of Figures 11A and 11B , illustrating further variants in which the sleeve is constituted by the superposition of three walls joined together by a detachment bonding means;
• the Figures 13 to 15 are perspective views further illustrating other single cut variants with high circumferential cut ( figure 13 ) or low ( figure 14 ), or an essentially axial cut ( figure 15 ), the detachable circumferential band having in the latter case the same height as the sleeve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The figure 1 illustrates a container 1 packed with an envelope according to the invention marked 100. The container 1 here comprises a substantially cylindrical body 2, and a closure cap 3, and the packaging envelope 100 tightly surrounds the body of this container as a result. heat shrink on it.

Such a container is of course given by way of example, to illustrate a particular case of object packaged in an envelope according to the invention. In particular, the control of retraction phenomena makes it possible to envisage the packaging of objects of much more complex shapes, while preserving the readability of the impressions carried by the sleeves constituting said packages.

The envelope 100, which is closed at a sealing line 130, is constituted by a heat-shrinkable plastic sleeve which in this case has the particularity of being constituted by the superposition of at least two walls which are secured together by a detachable bonding means. This feature is best seen on the cut of the figure 5 , which illustrates a variant with two walls denoted 101 and 102. The walls 101 and 102 are joined together by a detachment bonding means arranged in a layer denoted 115. This detachment bonding means relates generally to all of the surface of the envelope that is laid flat on the figure 4 .

On the figure 4 there are end areas 130.1 and 130.2 which are superimposed and sealed together to form a sleeve, which sleeve is then threaded onto the object to be packaged, and then retracted on the body of said object.

As will be seen later, it is essential that the walls 101 and 102 have substantially identical shrinkage characteristics to allow a homogeneous shrinkage of the sleeve 100 on the object 1. In practice, the constituent walls of the sleeve 100 will be realized from plastic films which are all mono-oriented transversely, or mono-oriented longitudinally. It is indeed important that the orientation mode is the same for the superimposed walls, so as not to introduce distortion during the heating of the sleeve for retraction. More specifically, it will be provided that the constituent films of the walls 101, 102 have necking curves and softening points which are essentially identical. The shrink curves and the softening points are indeed the basic criteria governing retraction of the heat-shrinkable plastic films. Of course, the constituent films of the walls 101, 102 may also differ from each other by the material and / or the color and / or the thickness, and / or the tactile appearance.

According to another characteristic of the invention, the wall 101, which is the outermost wall of the sleeve 100, further has, in the entire thickness thereof, at least one cutout delimiting at least a detachable circumferential band denoted 105. The cut-out (s) will generally be accurately marked with respect to the printing patterns carried by the detachable circumferential band 105.

On the figure 1 , there are thus two circumferential cutting lines 120, 121, which relate in the whole of the circumference of the envelope 100 retracted on the object 1. As is better visible on the section of the figure 5 , the cuts forming the lines 120, 121 are made half-way, that is to say that each of them is stopped in depth at the detachable bonding means 115. The cuts 120, 121 can be made when the envelope is flat, by mechanical cutting means (rotating blades), or by a laser beam, according to a continuous process. It is possible, in a variant, to provide circumferential cuts of length less than the complete circumference, the detachment then taking place with partial tearing of the wall 101.

For the detachment of the circumferential band 105, provision has been made on the figure 1 that the wall 101, which is the outermost wall of the sleeve 100, has, along a generatrix, and in this case over part of its height, an axial tear strip 107 which is delimited by two parallel lines of stitching or the like.106. The tear strip 107 furthermore has here a gripping tab 108 beyond the cutting line 120, which facilitates the gripping of said tear strip, and the removal thereof which is schematized on the figure 2 for the subsequent detachment of the detachable circumferential band 105.

The removal of the tear strip 107 thus makes it possible to disengage a gripping tongue 110 at the end of the detachable circumferential strip 105. It is then advantageously provided, behind the gripping tongue 110, a zone 109 of least resistance to tearing. peelability, that is to say offering a lower mechanical resistance to tearing, while remaining stuck to avoid differential shrinkage (greyed area on the Figures 1, 2 and 4 ) allowing the release of said tongue. This zone 109 can be obtained by localized deposit of a repellent varnish.

It is then sufficient to pull on the gripping tab 110 with a circular motion around the object 1, to detach the entire circumferential band 105 as shown in FIG. figure 3 .

We will now be concerned about the printing elements that are provided on the envelope 100 made according to the invention.

The circumferential band 105 is printed so as to have a printing pattern appearing on each side thereof. To allow a perfect readability by looking at one or the other face of the circumferential band 105, said band includes a means of adequate opacity. This opacity means may be present in the mass, using a film which is white or in color in the mass, or added to the surface, for example with a printed ink or a metallization printed in white on a surface of the film. This means of opacity is essential to ensure the legibility of the printing patterns appearing on each side of the circumferential band 105. It should be observed in this respect that the printing patterns can be printed on the same side of the circumferential band, since a means of opacity is interposed between these two patterns.

In the figures, the print patterns appearing on each side of the circumferential band 105 are illustrated by letters X and Y. Before detachment of the circumferential band 105 (FIG. figure 1 ), the user distinguishes only the letters X which are visible on the outer face 104 of the envelope 100. After detachment of the circumferential band 105 ( figure 3 ), the user can not only read the information symbolized by the letters X, but also the other hitherto invisible information symbolized by letters Y by examining the opposite side of said band. The circumferential band 105 then provides a printed information length representing approximately twice the circumference of the cylindrical object concerned, which is quite interesting when the objects concerned are of small diameter.

The other wall 102 of the sleeve 100 also has at least one printed pattern, particularly here behind the circumferential band 105, so that the corresponding printed pattern appears after detaching from said detachable circumferential band. On the Figures 1 to 3 the printed patterns which are visible from the outside are represented by letters Z. Before the detachment of the circumferential band 105 ( figure 1 ), the patterns printed in Z are visible above and below said strip. Then, once detached the circumferential band 105 ( figure 3 ), the central part of the wall 102, which is now visible with its information, provides an additional printing surface (letters Z) which was hitherto masked by the detachable circumferential band 105.

Thus, with the detachable circumferential band 105, there is a length of information corresponding to about three times the circumference of the object.

On the flat view of the figure 4 the letters X, Y and Z are diagrammatically illustrated, the letters Y being represented in dotted lines in reverse because they appear only in opposite vision, once the circumferential band 105 is detached, and the letters Z which are in rear of the circumferential band 105 are shown (in place) in dashed lines, because they appear only after detachment of said circumferential band. The letters X, Y, Z have also been indicated on the section of the figure 5 .

As illustrated on the Figures 6A and 6B , it can be provided that the walls 101, 102 constituting the 100 are superimposed, either independently ( Figure 6A ), or by folding the same wall ( Figure 6B ), with the interposition of a detachable bonding means 115.

The figure 7 , which is analogous to the figure 1 previously described, illustrates a variant in which the outermost wall 101 of the sleeve 100 has an additional cutout 111 which defines, with the circumferential cutouts 120, 121, a gripping tab 110 at the end of the detachable intermediate circumferential strip 105 .

The presence of this cutout 111 could risk weakening the envelope 100 during the retraction thereof on the object. It will then be possible to use a reinforcement technique which is described in detail in the document EP-A-0 775 643 of the plaintiff. A reinforcing tape denoted 112 is thus used, which is arranged along a generatrix of the sleeve 100, here over the entire height thereof, said reinforcing strip being provided behind the end edge of the gripping tongue 110. the species, because of the constitution of the sleeve 100 in two walls 101, 102, the reinforcing strip 112 is interposed between the two walls at the level of the cutout 111. Thus, the detachment of the circumferential band 105 is by simple gripping the tongue end 110, then detaching by rotation around the object, as illustrated on the figure 8 . Information is then available which is visible by examination of each of the faces of the circumferential band 105, in this case symbolized by letters X and Y. There is also illustrated in these figures a variant in which the wall 102 carries different information. according to the level of location, symbolized by the letters Z1 and Z2, the information corresponding to the letter Z2 being visible only after detachment of the circumferential band 105.

Again, as can be seen on the cut of the figure 10 , the cutting lines 120, 121 are made half-way, that is to say throughout the thickness of the wall of the film 101, to the thickness of the detachable bonding means 115.

As before, it is possible to assemble the walls by superposing them independently ( figure 11A ) or by folding the same wall ( Figure 11B ), with the interposition of a layer of the detachable bonding means 115.

The Figures 12A and 12B illustrate other variants in which the sleeve 100 is formed by the superposition of three walls 101, 102, 103 which are further secured to each other by a detachable bonding means 115. In these figures, a direct superposed arrangement ( figure 12A ) or by folding here double ( figure 12B ) of the same film wall. These three-layer layouts can still open the way for different ways of presenting information, but they also complicate printing techniques, especially if it is a single wall that is folded back on itself as this is illustrated on the figure 12B .

If desired, it can also provide that the detachable circumferential band 105 has an embossing (variant not shown). This may be advantageous for the tactile recognition of the circumferential band, but also, in the case of a releasable adhesive that is repositionable, thereby facilitating the application of the band flat on another medium once said detached band .

In general, it is possible to use a detachable bonding means which is peelable or repositionable.

The gluing means used may be different types: it may be a layer of glue, or alternatively a polymeric binder used during the coextrusion of the constituent films of the superimposed walls. It will also be possible to use an electric polarization of the surfaces of the facing walls by inversion of the electrostatic field (the bonding layer is then immaterial, which allows thin multiple walls).

It has thus been possible to achieve an envelope with an optimal printed surface capacity, even in the case of small diameters, while preserving a minimum size for the texts for readability thereof.

Numerous other variants can be provided that differ from the previous ones by the arrangement of the detachable circumferential band, for example by providing an upper band, respectively lower, defined by a single circumferential cut to half-flesh, the other edge of the band. detachable circumferential being the upper free edge, respectively lower, of the sleeve. Such variants have been illustrated in figure 13 for an upper band 105 defined by the single circumferential cutout 121 provided in the upper part of the sleeve 100, and to the figure 14 for a lower band 105 defined by the single circumferential cutout 120 provided in the lower part of the sleeve 100 (the upper and lower free edges of the cut wall 101 being denoted respectively 101.1 and 101.2). On these Figures 13 and 14 an axial tear strip arrangement 107 has been illustrated as in FIGS. Figures 1 to 4 but it is naturally only an example. It is also possible to provide a plurality of such circumferential bands, with more complex cuts made half-way through the thickness of the outermost wall of the sleeve (variant not shown here).

It will also be possible to provide a single substantially axial cut over the entire height of the sleeve 100, without circumferential cutout (s), as has been illustrated on FIG. figure 15 with the cutout 111 (here, behind said cutout, a reinforcing strip 112 as in Figures 7 to 9 ). In this case, the detachable circumferential band 105 has the same height as the sleeve 100, the edges of said band then being constituted by the upper free edges 101.1 and lower 101.2 of the cut wall 101.

Finally, and although this is not shown here, it will be possible to provide an envelope intended for the packaging of a group of objects, as is also described in the document EP-A-0 775 643 of the plaintiff already mentioned. A sleeve will then be used in two compartments, with a second sealing line arranged at a distance from the weld line 130, so as to define an intermediate membrane. The organization of the detachable circumferential band remains otherwise unchanged.

The invention is not limited to the embodiments that have just been described, but on the contrary covers any variant using, with equivalent means, the essential characteristics mentioned above.

Claims (20)

1. A cover for wrapping at least one article, the coverbeing of the type constituted by a sleeve of heat-shrinkable plastics material suitable for closely surrounding at least a portion of the article or a group of articles, the cover being characterized in that the sleeve (100) is constituted by superposing at least two walls (101, 102, 103) that are secured to one another by detachable adhesive means (115) generally covering the entire area of said cover, said walls having shrinkage characteristics that are essentially identical so as to enable the sleeve (100) to shrink uniformly onto the article or the group of articles, and the outermost wall (101) of the sleeve (100) further presents, through the entire thickness thereof, at least one cut (120, 121, 111) defining at least one part of a detachable circumferential strip (105), said circumferential strip being printed so as to present a pattern of printing that appears on each of its sides, the other wall(s) (102,103) also presenting patterns of printing, in particular behind the detachable circumferential strip (105) so that the corresponding pattern of printing appears after said detachable circumferential strip has been detached.
2. A cover according to claim 1, characterized in that the outermost wall (101) of the sleeve (100) presents a tear strip (107) along a generator line, the tear strip being defined by two parallel lines of perforations (106) or the like, with removal of the tear strip, in particular by means of a pull tab (108), enabling the detachable circumferential strip (105) to be detached subsequently.
3. A cover according to claim 1 or claim 2, characterized in that the outermost wall(101) of the sleeve (100) presents a cut (120, 121, 111) defining a pull tongue (110) at the end of detachable circumferential strip (105) .
4. A cover according to claim 3, characterized in that a zone (109) presenting reduced resistance to peeling is provided behind the pull tongue (110), thereby enabling said tongue to be separated.
5. A cover according to claim 3, characterized in that a reinforcing strip (112) is provided behind the end edge of the pull tongue (110), being disposed along a generator line of the sleeve (100).
6. A cover according to any one of claims 1 to 5, characterized in that it includes two parallel circumferential cuts (120, 121) defining an intermediate circumferential strip (105).
7. A cover according to any one of claims 1 to 5, characterized in that it includes a single circumferential cut (121)in the high portion of the sleeve (100), the other edge of the circumferential strip (105) as defined in this way being constituted by the top free edge (101.1) of the cut wall (101).
8. A cover according to any one of claims 1 to 5, characterized in that it includes a single circumferential cut (120) in the low portion of the sleeve (100), the other edge of the circumferential strip (105) as defined in this way being constituted by the bottom free edge (101.1) of the cut wall (101).
9. A cover according to any one of claims 1 to 5, characterized in that it includes a cut (111) that is essentially axial over the entire height of the sleeve (100), the edges of the circumferential strip (105) as defined in this way being constituted by the top and bottom free edges (101.1, 101.2) of the cut wall (101).
10. A cover according to any one of claims 1 to 9, characterized in that the detachable circumferential strip (105) includes means providing opaqueness, present in the mass of its material or applied to its surface, ensuring that the patterns of printing appearing on both sides of said circumferential strip are legible.
11. A cover according to any one of claims 1 to 10, characterized in that the detachable circumferential strip (105) presents embossing.
12. A cover according to any one of claims 1 to 11, characterized in that the walls (101, 102, 103) constituting the sleeve (100) are superposed independently, with the detachable adhesive means (115) being interposed.
13. A cover according to any one of claims 1 to 11, characterized in that the walls (101, 102, 103) constituting the sleeve (100) are superposed by folding a single wall, with the detachable adhesive means (115)being interposed.
14. A cover according to claim 12 or claim 13, characterized in that the detachable adhesive means (115) are peelable.
15. A cover according to claim 12 or claim 13, characterized in that the detachable adhesive means (115) are repositionable.
16. A cover according to any one of claims 1 to 15, characterized in that the adhesive means (115) are in the form of a layer of adhesive.
17. A cover according to any one claims 1 to 15, characterized in that the adhesive means (115) are in the form of a polymer binder used during coextrusion of the films constituting the walls 101, 102, 103).
18. A cover according to any one of claims 1 to 15, characterized in that the adhesive means (115) are in the form of electric polarization of the facing surfaces of the walls (101, 102, 103), presenting opposite electrostatic fields.
19. A cover according to any one of claims 1 to 18, characterized in that the walls (101, 102, 103) constituting the sleeve (100) are made from films of plastics material that are all mono-oriented, either all transversely or all longitudinally.
20. A cover according to claim 19, characterized in that the films constituting the walls (101, 102, 103) have shrinkage curves and softening points that are essentially identical, said films possibly otherwise differing from one another in material, and/or color, and/or thickness, and/or texture.

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