WO2002029768A2

WO2002029768A2 - Co-extruded polyolefin/petg film label

Info

Publication number: WO2002029768A2
Application number: PCT/FR2001/003062
Authority: WO
Inventors: Daniel Meilhon
Original assignee: Soplaril Sa
Priority date: 2000-10-06
Filing date: 2001-10-04
Publication date: 2002-04-11
Also published as: FR2815755A1; FR2815755B1; AU2001295659A1; WO2002029768A3

Abstract

The invention concerns an assembly comprising a container and its label, the label being integral with said container and completely enclosing the latter, the label is made of a film comprising at least three layers of which two are made of polyester and one of polyolefin, the polyolefin layer being located between the two polyester layers. The assembly can be produced by shrinkable sleeve process or by stretch label process.

Description

POLYOLEFIN / PETG COEXTRUDE FILM LABEL

The invention relates to the field of labels for containers such as bottles, cans, jars of jams and other containers of all kinds. More particularly, the invention relates to the labels which go around the entire container, so that they are in particular held in place by adhesion on itself after having gone around the container.

Usually, these labels are made of expanded polystyrene or polyvinyl chloride (PVC) or polyethylene (PE) or polypropylene (PP) or OPA and stuck on the container and on themselves with an adhesive , usually a hot melt. This hot melt being of a different nature from that of the label and of the container, the recycling of the label and of the container is made difficult since it requires a step of separation between the adhesive and the label, on the one hand and between the adhesive and the container on the other hand.

Furthermore, we want to be able to use transparent labels on transparent containers so that we can see the contents of the container through the label and the container. The use of an adhesive is therefore not recommended since it seriously affects the transparency in the places where it is applied.

According to the prior art, two methods are usually used for the production of this type of label, called the "sleeve" or "schrinkable label" method and the "surrounding label" method. The "shrink sleeve" process usually involves at least the following two steps after the formation of a film:

- fixing of the two edges of the film one on the other so as to form a tube (connection or longitudinal welding), then - cutting of the tube into sleeves at the desired heights, said sleeves falling around the containers to be labeled, then

- passage through a heated tunnel oven so as to cause the sleeve to shrink on the container to form the final label.

At this point, the label is attached to the container by tightening. The expression “retractable sleeve process” designates within the context of the present application any process which comprises the step of forming a sleeve (that is to say a cylinder), which is placed around a container then shrunk by heating to tighten the container.

This process requires that the film has retraction properties in the transverse direction relative to the direction of the longitudinal weld, so that the retraction effectively exerts a tightening of the container. Generally, the longitudinal fixing is carried out by welding the edges of the film as it comes from the extrusion and it therefore has the same direction as the direction of the extrusion ("machine direction").

In order for the film to have a property of retraction in the transverse direction with respect to the longitudinal attachment and therefore also with respect to the machine direction, it is necessary to draw in the transverse direction so that the retraction effectively exerts a tightening of the container. Indeed, the extrusion of the film gives shrinkage properties to the film in the "machine direction", which, by itself, would lead to a retraction of the label especially in height, more than in the direction of a tightening of the container. The transverse stretching causes a strong weakening of the retraction properties in the "machine direction" and gives retraction in the transverse direction, which is desired.

The "surrounding label" process involves the following steps:

extrusion of the film in a width corresponding to the desired height of the label, or extrusion of the film in a width greater than the desired height of the label, followed by cutting in the direction of the extrusion so as to obtain one or more strips of width corresponding to the desired height of the label, then

- fixing the end of the film over its width on the container along a first connecting line, then - surrounding the container with the film and cutting along a length slightly greater than the perimeter of the container so that the label overlaps it - even then

- fixing of the label on itself according to a second connecting line, then

- if necessary, passage through a heated tunnel oven so as to cause the film to shrink in the direction of tightening of the container.

According to this method, the printing of the film is carried out before the first attachment to the container, either after extrusion, or after the film has been cut in the direction of extrusion. According to the prior art, the fixing of the film to the container and the fixing of the film to itself after surrounding the container, are produced by an adhesive such as a hot melt.

If just after the second attachment of the label (on itself), the tightening of the container is sufficient, it is not necessarily essential to carry out the retraction heating.

If one does not carry out a retraction, it is in this case desirable that the container is undeformable during its handling, as it is the case if it is out of glass, metal, thick plastic. Indeed, if the container is deformable when it is used, for example when it is taken in the hand, the label may tend to float around the container, especially if the latter has been partially emptied of its original content.

However, the retraction heating may be preferred so that the label fits perfectly with the container, which gives a better aesthetic appearance to the assembly and eliminates any possible problem of floating around the container.

In this process of the surrounding label, there is no need to resort to stretching in the transverse direction. Indeed, the film this time surrounds the container so that the "machine direction" coincides with the perimeter of the container. Thus, the retraction in the machine direction caused by the extrusion is used wisely when passing through the tunnel oven because it goes in the direction of tightening the container. Therefore, this machine-not shrinking property should not be combated here by a transverse orientation.

The invention relates to the labeling of containers of any kind, for example plastic, or metal, or glass, or the like, by the method of the shrink sleeve or the surrounding label.

Films applying for this type of application must meet a set of criteria, including the following:

- good shine,

- sufficient rigidity so that the film exhibits a favorable behavior when handled by printing and labeling machines (good machinability), - good transparency, in particular if the contents of the container must be visible, and / or if the printing is to be carried out on the internal face of the film, in contact with the container,

- good ability to be cut, - good ability to be bound to the container and to itself, in particular by the use of a solvent, while offering sufficient resistance to the solvent to prevent it from penetrating it, - good mechanical resistance, in particular to tear, - good printability, which implies good dimensional resistance and high surface tension (at least 38 dynes). According to the invention, a film comprising at least two layers of polyester and a layer of polyolefin situated between the two layers of polyester, is used for the production of labels which go completely around containers. This film can subsequently be called "complex film".

The invention relates to the assembly comprising a container and a label, the label being integral with said container and entirely surrounding the latter, the label being obtained from a film comprising at least three layers, two of which are made of polyester and one is made of polyolefin, the polyolefin layer being located between the two polyester layers.

In particular, the invention makes it possible to use no adhesive to make the label and the container integral.

The film can be applied to the container using the shrink sleeve method. In this case, contrary to what is usually done, no stretching is carried out after the extrusion of the complex film. In the context of this method applied to the present invention, one starts from two reels of the film, the two reels being unwound so that the two films are juxtaposed one on the other. The two juxtaposed films are then welded to each other and cut into portions along transverse lines relative to the direction of extrusion so that they form flattened sleeves, the distance between said lines being equal to 1 / 2 perimeter of the sleeves that one wishes to achieve. The sleeves thus formed have a perimeter substantially greater than that of the container to be labeled. They have a shrinking property in the sense of a reduction in their diameter (therefore capable of clamping the container) which has been imparted to the film by its extrusion. Placed around the container, they are then subjected to a shrinking step by heating. In the context of this process, the welds are "autogenous", that is to say without the addition of additional material, and are carried out by hot welding between the layers polyester film of the complex film, the heat necessary for said welding can for example be provided by high frequency or ultrasound.

The film can be applied to the container using the surrounding label method. In the context of this process, the two bonds can be produced by using a polyester solvent. According to the latter technique, the solvent is applied between the two surfaces to be bonded. The solvent diffusing into the polyester makes it locally and temporarily viscous, which allows it to weld on itself. The solvent then evaporates to disappear almost completely from the film. This fixing means can also be considered to be an autogenous weld, that is to say causing a weld of the material on itself without definitive contribution from a third body. In the context of the present application, this fixing means is called "by coating / evaporation of solvent" or "solvent welding", which is a true cold welding.

The two film attachments required by the surrounding label technique can also be made using an adhesive such as a hot melt. However, as far as possible due to the nature of the materials used, the solvent coating / evaporation technique will advantageously be used. It is at least possible to use solvent welding for the second fixing, since the film then comes on itself, one of the polyester layers coming into contact with the other polyester layer. Of course, it is necessary not to cover the polyester layers at this point of the second fixing (for example with a printing layer) if it is desired to use the solvent technique. If the container to be surrounded has an external polyester surface, it is also possible to use the solvent technique for the first fixation. The complex film is therefore particularly suitable for producing labels according to the surrounding label method, on containers whose external surface is made of polyester, and in particular polyester bottles such as polyethylene terephthalate (PET), since the two Label attachments can be made by the solvent technique.

The advantage of the invention, in particular compared to a technique which would make use as a label of a monolayer polyester film, is that the solvent technique is much more easily applicable. In fact, in the case of a single-layer polyester film, the solvent may perforate the film in certain places, if its application is poorly controlled. In the case of the complex film used within the framework of the present invention, the polyolefin layer plays a barrier role with respect to the solvent, which prevents the film from being punctured, even if the solvent has been applied in a higher amount. in some places due to irregular or poorly controlled application.

Particularly suitable as solvent, tetrahydrofuran (THF) and ethyl acetate, the latter being preferred because of its low toxicity.

The complex film used in the context of the present invention is particularly transparent. It can be useful to use this transparency to make the contents of the container visible, if of course the container is itself transparent. The use of an adhesive as a hot melt deteriorates the transparency in the places where it is applied. On the other hand, the use of the solvent technique does not significantly change the transparency in the places where the solvent has been applied. Of course, in this case, the film is only printed on part of its surface, so that it can effectively benefit from the transparency qualities of the label and of the container.

In particular, the invention allows, by the method of the surrounding label, the production of a container / label assembly, the label being only partially printed and being transparent in the unprinted places, the container being transparent, the label covering itself in a print-free covering zone, the label being fixed on itself on the one hand and on the container on the other hand by coating / evaporation of solvent.

The complex film used in the context of the present invention is a multilayer film generally having a thickness ranging from 5 to 1 00 μm and more generally from 1 0 to 60 μm.

The film comprises at least three layers, two of which are made of polyester and one of which is made of polyolefin. The polyolefin layer is located between the two polyester layers. Preferably, the film comprises a plane of symmetry which is parallel thereto, said symmetry applying both to the geometry and to the composition of the film.

The sum of the mass of the layers comprising the polyester can represent at least 20% by weight of the mass of the film. Preferably, the film consists of at least three main layers, two being of polyester and one being of polyolefin, that of polyolefin being in the middle of the film, so that it includes the plane of symmetry of the film. By "three main layers" is meant that the sum of the masses of these three layers constitutes at least 80% of the total mass of the film and that each of these three layers obtained from a thermoplastic material constitutes at least 1 0 % by weight of the total mass of the film.

Throughout the present application, when mention is made of a layer "based" on a certain material, this means that the layer comprises at least 60% by weight of said material.

By polyolefin is meant a polymer of at least one olefin, the term polymer having to be taken in the broad sense, so that it covers the notions of homopolymer, copolymer, terpolymer, interpolymer, or a blend of polymers. As olefin, there may be mentioned ethylene, propylene, butene, hexene, 1-octene. As the polyolefin, a polymer of propylene or ethylene is preferred, the latter being more preferred. The polymer of at least one olefin can therefore result from the polymerization of at least one olefin with at least one other monomer, which can be an olefin or another monomer such as for example vinyl acetate, maleic anhydride or an acrylic ester.

In the case where it is not particularly sought to impart shrinkability properties to the film, a homopolyethylene or a copolymer of ethylene rich in ethylene (at least 80% ethylene), or a homopolypropylene can be used as polyolefin. or a propylene-rich propylene copolymer (at least 80% propylene).

In the case where it is desired that the film has shrinkability properties, use is preferably made, as polyolefin, of a copolymer of ethylene and of an alkyl (meth) acrylate or of a copolymer of ethylene and of a vinyl ester of a saturated carboxylic acid.

As the copolymer of ethylene and an alkyl (meth) acrylate, the alkyls can have up to 24 carbon atoms. Examples of alkyl acrylate or methacrylate are in particular methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate. As regards the copolymer of ethylene and a vinyl ester of a saturated carboxylic acid, the ester can be vinyl acetate, vinyl propionate or vinyl butyrate.

In these copolymers of ethylene and of a (meth) acrylate or of a vinyl ester, the content of comonomer is preferably between 4 and 30% by weight.

An EVA (ethylene-vinyl acetate copolymer) containing 4 to 30% by weight of vinyl acetate is more particularly preferred when the film must have shrinkability properties. A polyester is usually prepared by polycondensation of one or more diacid (s) (also called dibasic acid) with one or more diol (s) (also called glycol (s)). It is recalled that a polyester obtained from a polycondensation medium comprising terephthalic acid and ethylene glycol is usually called "polyethylene terephthalate" and usually designated by the abbreviation "PET".

The polyester used to produce the complex film is preferably obtained from the polycondensation of terephthalic acid with ethylene glycol and a diol comprising at least three carbon atoms.

Such a polyester is usually called "polyethylene terephthalate glycol" and usually designated by the abbreviation "PETG".

The polyester can be chosen from amorphous or semi-crystalline polyesters. By amorphous is meant that the polyester has less than 15% of crystallinity and preferably less than 10% of crystallinity.

The amorphous and semi-crystalline polyesters can be produced by methods known in themselves. Thus, amorphous polyesters are usually made by melt phase techniques ("melt phase techniques" in English) and crystalline polyesters are usually made by a combination of melt and solid phase polycondensation procedures. Preferably, the polyester is amorphous.

The polycondensation medium leading to the polyester comprises terephthalic acid, ethylene glycol, a diol comprising at least three carbon atoms and, where appropriate, other diacids and / or other diols.

A particularly suitable polyester is a copolymer resulting from the polycondensation of terephthalic acid with ethylene glycol and cyclohexane dimethanol, especially when it is amorphous. This means that the polycondensation medium comprises terephthalic acid, ethylene glycol, cyclohexane dimethanol, and where appropriate other diacids and / or other diols, the final polyester being more particularly suitable when it is amorphous. .

Thus, the diacid component of the polyester can comprise 70 to 100 mol% of terephthalic acid and 0 to 30 mol% of another acid chosen from isophthalic acid, naphthalenedicarboxylic acid, acid 1, 4- cyclohexanedicarboxylic or mixtures thereof. Preferably, the diacid component contains from 80 to 100% by mole of terephthalic acid and 0 to 20% by mole of isophthalic acid.

The diacid component can be modified by a small amount, namely up to 10 mol%, of a diacid containing 4 to 40 carbon atoms such as an isomer of naphthalenedicarboxylic acid or their mixtures, the isomers 1 , 4-, 1, 5-, 2,6- and 2,7- being preferred, or such as a cis, trans isomer or a mixture of cis / trans isomers of 1,4-cyclohexanedicarboxylic acid, or such as sulfoisophthalic acid.

The diol component of the polyester can be derived from diols (that is to say glycols) comprising 2 to 10 carbon atoms and their mixtures. Preferably, the diol component contains 2 to 99 mol% of 1,4-cyclohexanedimethanol and 1 to 98 mol% of ethylene glycol, and more preferably 25 to 40 mol% of 1,4 cyclohexanedimethanol and 75 to 60% by mole of ethylene glycol.

The diol component can be modified by up to 20 mol% of other glycols such as diethylene glycol, neopentyl glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1, 8-octanediol, the

2,2,4-trimethyl-1,3-pentanediol, propylene glycol, 1,3-propylenediol.

The polyester can be chosen from those whose intrinsic viscosity ranges from 0.4 to 1.5 dL / g, and preferably from 0.6 to 1.2 dL / g, said viscosity being determined at 25 ° C. using 0 , 25 g of polymer per 100 ml of a solvent composed of 60% by weight of phenol and 40% by weight of tetrachloroethane.

The polyolefin layer can represent 40 to 80% by weight of the mass of the film. Each of the two polyester layers can represent from 1 0 to

30% of the mass of the film. The film may comprise one or more binders, promoters of adhesion of interfaces, between the different layers. Such binders are generally present between the layers of the film at a rate of 1 to 5 μm.

It is also possible to mix one or more binder (s) with at least one of the materials constituting at least one of the layers of the film, so as to increase the compatibility and therefore the adhesion of said layer to at least 1 'one of the layers which is juxtaposed to it. Generally, such a binder can be present in the selected layer, at a rate of 10 to 40% by weight. Of course, at least one of the ingredients (binder and / or thermoplastic resin) useful in the manufacture of the film may contain at least one adjuvant or additive, such as a dye or pigment, antioxidant, anti-UV agent, agent slippery, anti-blocking agent, incorporated in a usual manner and known to those skilled in the art, taking into account the ingredient chosen.

At least one slip agent can be incorporated into at least one ingredient of the film, prior to its preparation by extrusion or coextrusion. The slip agent is preferably incorporated into the outermost coextruded layers. Such a slip agent can for example be chosen from amides of fatty acids such as erucamide and can be introduced at a rate of 200 to 5,000 ppm into the thermoplastic material from which the film layer or layers containing this slip agent will be derived.

In general, such a slip agent is incorporated into the film if it is not intended to metallize or print it.

At least one antiblocking agent can be incorporated into at least one ingredient of the film, prior to its preparation by coextrusion.

The anti-blocking agent is preferably introduced so as to be present towards the external layers of the film, for example the two outermost layers having been coextruded, but being located just below the non-coextruded layer (s), that is to say that is to say printing and / or metallization and / or coating with an antistatic agent, if the latter are provided. This anti-blocking agent has the function of reducing the tendency of the film to adhere to itself when it is wound in a reel, so as to facilitate its unwinding. Such an antiblocking agent generally comprises particles of mineral filler such as silica and can be incorporated into at least one of the layers in the form of a master batch of mineral filler / thermoplastic resin

In the case where the anti-blocking agent comprises a mineral filler, the anti-blocking agent can be incorporated in at least one layer so that the mineral filler is present in said layer at a rate of 1 000 to 10 000 ppm.

Prior to its use, it is possible to impart antistatic properties to the film. These antistatic properties allow the film to stay flat and slide well on the manufacturing machines, without having a tendency to roll up on itself, which would risk disturbing or even blocking the entire manufacturing process.

These antistatic properties can be applied to the film on the basis of the principles known to a person skilled in the art, that is to say, either by adding at least one antistatic agent in at least one of the ingredients (resin and / or binder) entering into the composition of the film, prior to the manufacture of the latter, either by coating the film on its external layers with a solution of an antistatic agent, or by any other suitable means. Antistatic agents of the alkylamine family are known to those skilled in the art In general, coating with an antistatic agent corresponds to a final surface treatment of the film, so that it results in the production of the outer layers of the film

This coating with an antistatic agent is therefore carried out in particular after the possible printing step. In general, it is not necessary to use a coating with an antistatic agent if the film has been metallized

In the case where it is desired to apply printing and / or metallization to the film, it is preferable to carry out a corona treatment on the film prior to said printing and / or metallization. Such a corona treatment can be applied to the film, on the basis of the principles known to a person skilled in the art Nevertheless, a satisfactory metallization result is obtained even in the absence of corona treatment

The complex film used in the context of the invention can for example be obtained by coextrusion in a flat die (often called "cast" extrusion) or by blowing coextrusion (also called "tubular") In the coextrusion process in a flat die, a flat film is coextruded and continuously deposited on a cooling cylinder also called a "chill-roll".

The use of the "cast" process makes it possible to benefit from a surfacing effect of the cooling cylinder, leading to a particularly smooth film and therefore having a good surface condition.

In the blown coextrusion process, the film is coextruded in the form of a cylindrical bubble obtained by inflation from an annular die. For this process, the draw rate can range from 2 to 50 and preferably from 1 0 to 30, the inflation rate can range from 1 to 1 0 and preferably from 1.5 to 3, the air gap can range from 0.5 to 5 mm and preferably 0.8 to 1.6 mm. We can play on the printing speed to influence the thickness of the film. Generally, the drawing speed can range from 10 to 150 m / min, and preferably from 30 to 60 m / min. Figure 1 shows the realization of the tube by placing a film edge on the other edge for fixing, in the context of the process "retractable sleeve" of the prior art. Here, the film is unwound from a reel. The direction of extrusion corresponds to the direction of unwinding of the reel (indicated by an arrow on the film). Here, the film was stretched to give it shrinkage in the transverse direction relative to the direction of extrusion.

Figure 2 shows a sleeve (1) falling around a container (2) as part of the "shrink sleeve" process.

Figure 3a shows the attachment of the end of a film (1) along a first connecting line (3) shown schematically by a dotted line, on a bottle (2), in the context of the surrounding label process. The film is unwound from a reel. The direction of unwinding corresponds to the direction of extrusion of the film. The film was not stretched after extrusion.

Figure 3b shows, seen from above, the bottle after fixing the label. Two lines of fasteners (3) and (4) hold the label on the bottle.

FIG. 4 shows a label (1) surrounding a container, the label having an impression on its internal face shown diagrammatically by a dotted line (3). An area (x) of the inner face has no printing so as to be able to fix the film in this area (x) by the solvent technique.

FIG. 5 schematizes a step used in the context of the retractable sleeve method applied to the present invention. The FIG. 5a shows the superposition of two complex films of the same nature and their welding / cutting at the locations indicated by dotted lines so as to form flattened sleeves. The sleeve thus formed, ready to fall around the container (on the principle of what is shown diagrammatically in FIG. 2) is shown in FIG. 5b. The sleeve has two lines of welds (3) and (4) produced during the operation shown in FIG. 5a.

EXAMPLE 1 (adapt to EVA)

We will now describe an embodiment and use of a three-layer film of the polyester / EVA / polyester type. In this example, the starting materials are designated by abbreviations, the meaning of which is given in this table:

The three layers of the film are described in this table

The film was produced by tubular coextrusion under the following conditions:

- screw temperature of the PETG / AB mixture - screw temperature of the EVA

- die temperature

- head temperature

- drawdown rate - inflation rate: 2

- air gap: 1, 2 mm

- pulling speed: 40 m / min

The film obtained has a width of 800 mm and a total thickness of 28 μm and a density of approximately 1.1.

The film is printed on the side intended to be in contact with the container, so that the impression will be visible through the film. The film is, however, free of printing at the places intended for the fixing lines according to the solvent technique. The film is then cut into strips, the height of which corresponds substantially to the height of the desired labels, each strip being wound in a reel. The reel strip unwinds in the same direction as the direction of film extrusion. A label is then applied to a PET bottle according to the method of the surrounding label. This application is carried out manually but could of course be carried out by machines operating according to this process.

The first attachment of the label to the bottle is carried out as follows:

- we brush the part of the internal face of the label free of printing using a cotton swab impregnated with ethyl acetate,

- we apply the brushed part of the label with the hands on the PET bottle, and we realize after a few seconds that the label is sufficient on its own on the bottle,

- We go around the bottle to the label after having brushed the other internal end of the label intended to cover the part already fixed, and we apply the newly brushed part on the part of the label already fixed . We realize after a few seconds that the label stands alone on the bottle.

We then pass over the label a flow of hot air (using a hand-operated heat gun) and we see that the label retracts to fully fit the container. EXAMPLE 2

An embodiment and use of a three-layer film of the polyester / polyolefin / polyester type will now be described. In this example, the starting materials are designated by abbreviations, the meaning of which is given in this table:

The film was produced by tubular coextrusion under the following conditions:

- screw temperature of the PETG / AB mixture: 220 ° C.

- screw temperature of the mixture: MDPE / HDPE / terpolymer: 180 ° C

- die temperature: 190 ° C - head temperature: 200 ° C

- drawdown rate: 20

- inflation rate: 2

- air gap: 1.2 mm

- drawing speed: 40 m / min The film obtained has a width of 800 mm and a total thickness of 28 μm and a density of approximately 1.1. We proceed to the production of a label on a PET bottle as in Example 1. The label is correctly attached to the bottle. However, it can be seen that the label does not retract as well as in Example 1.

Claims

REVENDI CATI O NS

7. An assembly comprising a container and a label, the label being integral with said container and entirely surrounding the latter, the label being obtained from a film comprising at least three layers, two of which are made of polyester and one of which is made of polyolefin, the polyolefin layer being located between the two polyester layers.

2. Assembly according to the preceding claim, characterized in that no adhesive is used to join the label and the container

3. Assembly according to one of the preceding claims, characterized in that the polyester is obtained from the polycondensation of terephthalic acid with ethylene glycol and a diol comprising at least three carbon atoms.

4. An assembly according to the preceding claim characterized in that the diol is cyclohexane dimethanol.

5. Assembly according to one of the preceding claims, characterized in that the polyester is amorphous

6. Assembly according to one of the preceding claims, characterized in that the film comprises a plane of symmetry which is parallel to it, said symmetry being applied both to the geometry and to the composition of the film, the polyolefin layer including said plane of symmetry

7. Assembly according to one of the preceding claims, characterized in that the sum of the masses of the three layers constitutes at least 80% of the total mass of the film and that each of these three layers obtained from a thermoplastic material, constitutes at minus 10% by weight of the total mass of the film

8. Assembly according to one of the preceding claims, characterized in that the polyolefin is a copolymer of ethylene and of a (meth) alkyl acrylate or a copolymer of ethylene and a vinyl ester of a saturated carboxylic acid.

9. An assembly according to the preceding claim characterized in that the polyolefin is an ethylene-vinyl acetate copolymer containing 4 to 30% by weight of vinyl acetate.

70. Assembly according to one of the preceding claims, characterized in that the container has an external polyester surface.

7 7. An assembly according to one of the preceding claims characterized in that the label is only partially printed and is transparent in unprinted places and in that the container is transparent.

72. An assembly according to claim 1 0 characterized in that the label has been fixed to the container by coating / evaporation of solvent.

73. An assembly according to the preceding claim characterized in that the label is only partially printed and is transparent in the unprinted places and in that the container is transparent and in that the label covers itself in an area cover free of printing, the label being fixed on itself on the one hand and on the container on the other hand by coating / evaporation of solvent.

74. A method of preparing an assembly according to one of claims 1 to 1 1, characterized in that two thicknesses of the film are juxtaposed one on the other, welded and cut into portions along transverse lines relative to the direction of extrusion, so as to form flattened sleeves, the distance between said lines being equal to 1/2 of the perimeter of the sleeves to be produced, the sleeves thus formed having a perimeter substantially greater than that of the container to be labeled, then in placing said sleeves around the container and shrinking by heating so that the sleeve squeezes the container to form the label.

75. A method of preparing an assembly according to one of claims 1 to 1 3, characterized in that the film is first fixed on the container along a first connecting line, then unwound around the container until it cover on an overlap area, the direction of unwinding corresponding to the direction of its extrusion, then fixed on itself along a second connecting line in the overlap area.

76. Method according to the preceding claim, characterized in that the connecting lines are produced by coating / evaporation of solvent.

77. Method according to the preceding claim, characterized in that the solvent is ethyl acetate.

78. Method according to one of claims 1 5 to 1 7 characterized in that the external surface of the container is made of polyester.

79. Method according to one of claims 1 5 to 1 8, characterized in that a shrinkage heating is then exerted on the label.

20. Method according to one of claims 14 to 1 9 characterized in that no adhesive is used for fixing the label.