WO1999038685A1

WO1999038685A1 - Film for wrapping objects

Info

Publication number: WO1999038685A1
Application number: PCT/FR1999/000086
Authority: WO
Inventors: Daniel Meilhon
Original assignee: Soplaril S.A.
Priority date: 1998-01-29
Filing date: 1999-01-18
Publication date: 1999-08-05
Also published as: AU2059599A; RU2213665C2; FR2774078A1; BR9908135A; PL341862A1; NO20003726D0; AU751843B2; CA2318460A1; CN1295516A; HUP0100264A2; HUP0100264A3; NO20003726L; TR200002187T2; IL137271A; NZ505864A; IL137271A0; EP1051298A1; FR2774078B1; JP2002501863A

Abstract

The invention concerns an assembly comprising a solid, for example a sweet and its wrapper, said wrapper consisting of a film comprising at least a twist wrap and/or fold comprising at least a layer including at least a polyester. The film can be single-layer or multilayer and has good wrapping ability.

Description

1

FILM FOR THE WRAPPING OF OBJECTS

The invention relates to an assembly comprising a solid and its packaging, said packaging comprising at least one film comprising at least one foil and / or a fold, said film comprising at least one layer comprising at least one polyester. The invention relates directly to the field of packaging food materials such as candies such as chocolates, candies, boiled or caramel sugars, "chewing gum", lollipops, but also that of any other solid object ^"' such as soaps, cheeses in portions, culinary additives in doses such as broths in cubes Figures 1 and 2 show, by way of example, candies after wrapping in the context of the present invention.

The packaging in question in the present application can therefore be a film directly marrying most, if not almost all, of the surface of the packaged solid, the latter generally being made up of a single element (as opposed for example to a powder made up of several elements in the form of particles), as is the case for example for a candy. Of course, in the context of the present invention, the assembly may include

- the solid object,

- itself first wrapped by a first film or paper, if necessary metallized,

- itself wrapped by the film comprising at least one foil and / or a fold and comprising at least one layer comprising at least one polyester.

According to the prior art, the candies can be wrapped using polyvinyl chloride (PVC) or cellophane films. PVC is, in general, in the process of substitution, and is moreover of high density so that it significantly increases the batches of packaged candies. Cellophane is made by a complex process making it expensive and its producers are fewer and fewer. There is therefore a need for substitutes for these two materials, in particular in the field of films for wrapping solid objects such as candies.

A film suitable for wrapping a solid must meet several technical criteria. In particular, the film must be suitable for wrapping, that is to say ^" it must keep the shape which was given to it during wrapping with the lowest possible tendency to return to its shape d origin, that is to say of flat film. This property makes it possible to avoid having to use an adhesive or a glue, for example at the level of the tightest zone of a foil, that is to say that is, between the packaged solid and the foil itself, to keep the package in the shape it has been given.

This tendency of the film not to keep the shape that we have sought to give it is more particularly difficult to overcome when it is desired to impart one or more twists to the packaged solid, as for the candies represented in FIG. 1.

One can easily test the ability of a film to wrap a solid to make a package comprising at least one foil and / or a fold, by observing whether a foil tends to go back after it has been formed. This test can be carried out by forming a twist of a half-turn, that is to say by making the part of the film which does not grip the solid perform, 1/2 turn relative to the wrapped solid.

A film for wrapping solid objects must also be easy to handle by the machines responsible for wrapping said objects, from which the highest possible rates are expected, for example 50 to 1500 objects wrapped per minute and per machine.

The film must therefore also be easy to cut. Indeed, before wrapping an object, it is necessary to cut the surface of film useful for wrapping said object, generally from a reel of said film. The film, before wrapping the object, before and after mechanical cutting, must remain flat and must not show any tendency to roll up on itself. Indeed, such a trend could disrupt the production chain and lead to its blocking.

In addition, depending on the case, the film may have to have a good gloss and / or suitable transparency, and / or good suitability for food contact and / or satisfactory organoleptic properties.

Where appropriate, the film must be able to exhibit good printability and / or metallization. The film must also be easy to manufacture from its basic materials. A single-material film made of biaxially oriented high density polyethylene or biaxially oriented polypropylene does not satisfactorily meet the specifications of the application in particular because its capacity for wrapping is low. In addition, these materials extruded by the extrusion-blowing process, commonly called "bubble" process, ^" have poor optical properties due to the presence on the surface of nodules causing diffraction of light.

The film according to the invention addresses the above-mentioned problems. In particular, the film according to the invention makes it possible to package a solid by a package comprising at least one foil and / or a fold without the need for an adhesive or glue. In particular, it is not necessary for the film to act as an adhesive itself, which would be somewhat the case if the film were heat sealed on itself to keep the packaging sufficiently closed. Thus the film according to the invention allows the production of a packaging kept closed around an object by the mere production of at least one foil (also called "stranding") and / or at least one fold, without it do not necessarily need to use a cold or hot seal at any point of the packaging after wrapping the object. For the production of this packaging, it is also not necessary to fix on the film, and therefore in excess thickness to said film, reinforcements, such as for example bendable rods which may be metallic, so as to maintain the packaging around its content thanks to the non-elastic folds exerted on said rods.

The film used in the context of the present invention comprises at least one layer comprising at least one polyester. It can therefore be an essentially monolayer film or a multilayer film. This film generally has a thickness ranging from 5 to 1 00 μm and more generally from 10 to 60 μm.

The film is said to be essentially monolayer if its manufacture only required the extrusion of a single thermoplastic material even if, if necessary, it received, after said extrusion, the usual finishing layers such as a metallization layer and / or printing and / or coating with an antistatic agent.

The film is said to be multilayer in the context of the present application if it comprises at least two layers of different thermoplastic materials.

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. This implies that if the film is multilayer and comprises at least two layers of different composition, the film necessarily comprises at least three layers. 4

The sum of the mass of the layers comprising a polyester can represent at least 20% by weight of the mass of the film.

The film may consist of at least three main layers, one of which, with a composition different from the other two, is 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 mass 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 10% by weight of the total mass of the film.

In the case of a film comprising at least three main layers in the sense given above, the middle layer may comprise at least one polyolefin and the other two, substantially identical, layers may comprise at least one polyester. The film comprising at least three main layers in the sense given above has an excellent tearability (substantially linear tear) in all directions, in particular both in the direction of the coextrusion and in the direction perpendicular to the coextrusion . This film is therefore also particularly suitable for applications requiring good tearability in the direction perpendicular to the direction of coextrusion.

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. Alternatively, the film comprises at least one layer comprising at least one polyester and at least one layer comprising at least one polyolefin.

Preferably, the film according to the invention comprises at least one layer of polyester, said film being essentially monolayer, or said film being multilayer and comprising in this case at least one layer comprising at least one polyolefin.

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 5 therefore be derived from the polymerization of at least one olefin with at least one other monomer, which may be an olefin or another monomer such as for example vinyl acetate, maleic anhydride or an acrylic ester. In the case of a film comprising at least three main layers in the sense given above, the middle layer is advantageously based on a polymer of ethylene. This ethylene polymer can be such that at least 80% of the monomer units constituting it is ethylene. By polyester is meant a polymer comprising at least one ester function as a repeating unit, the term polymer here also covering the concepts of homopolymer, copolymer, terpolymer, interpolymer and mixture of polymers.

The polyester can be derived from the condensation of terephthalic acid and at least one diol.

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.

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".

A preferred polyester is a copolymer which can be obtained from the condensation (also called 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". 6

This means that the polycondensation medium 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 copolymerization (in fact polycondensation) of terephthalic acid with ethylene glycol and cyclohexane dimethanol, in particular 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% by mole of terephthalic acid and 0 to 30% by mole 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 mol% 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, 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. 7

In the case of a film comprising at least three main layers in the sense given above, the middle layer can represent 40 to 80% by weight of the mass of the film.

For the case of a film comprising at least three main layers in the sense given above, one can for example cite the combination in which the middle layer is based on an ethylene polymer and represents from 40 to 80 % by weight of the mass of the film, each of the other two layers being based on a polyester which is a copolymer resulting from the condensation of terephthalic acid with ethylene glycol and a diol comprising at least three carbon atoms , each of these two other layers representing from 10 to 30% of the mass of the film, said polyester preferably being amorphous, and said diol comprising at least three carbon atoms which may be cyclohexanedimethanol. Where appropriate, for the case where the film is multilayer, 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 chosen 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. In the case of a multilayer film and in the case where this film is intended to wrap a food material, it may, depending on the case, prefer to incorporate the adjuvant or additive in the middle layer of the film, if it is desired to reduce the risk of pollution of the food material finally wrapped, by said adjuvant or additive. At least one slip agent can be incorporated into at least one ingredient of the film, prior to its preparation by extrusion or coextrusion. If the film is multilayer, the slip agent is preferably incorporated in the outermost coextruded layers. Such an agent 8 slip can for example be chosen from amides of fatty acids ^{^} such as erucamide and can be introduced at a rate of 200 to 5000 ppm in the thermoplastic material from which the layer or layers of the film 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 extrusion or coextrusion. In the case where the film comprises several layers, 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 lying just below the or non-coextruded layers, 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 within at least one of the layers in the form of a master batch of mineral filler / thermoplastic resin.

For 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 1 000 ppm.

Prior to its use for wrapping objects, it is possible to give the film antistatic properties. These antistatic properties allow the film to keep well flat and to 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 principles known to those 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 using a solution of an antistatic agent, or also by 9 any other appropriate means. Antistatic agents of the family of ^" alkylamines are known to those skilled in the art.

In general, the 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. For 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 according to the invention, on the basis of the principles known to those skilled in the art. However, if the film is essentially monolayer or produced so that its outermost coextruded layers contain at least one polyester, a satisfactory metallization result is obtained even in the absence of corona treatment.

The film used in the context of the invention can for example be obtained by extrusion or coextrusion in a flat die (often called "cast" extrusion) or by extrusion or coextrusion blow molding (also called "tubular"). The term extrusion applies to the production of a monolayer film, while the term coextrusion applies to the production of a film comprising at least two layers. In the extrusion or coextrusion process in a flat die, a flat film is extruded or coextruded and continuously deposited on a chill roll also called "chill-roll".

After extrusion or coextrusion in a flat die, the film preferably undergoes monoaxial or biaxial stretching (respectively producing a mono or biorirection) on the basis of the principles known to those skilled in the art. A monoaxial stretching is carried out in the direction of extrusion or coextrusion ("machine direction"), while a biaxial stretching is carried out both in the direction of extrusion or coextrusion and in the direction perpendicular to the extrusion or coextrusion. 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. 10

Mono or bi-orientation has the particular effect of increasing the ^" density of the film and of reducing its resistance to the flow threshold.

The stretching or the bi-stretching can be carried out continuously or "in recovery", that is to say after rewinding and temporary storage of the film just after the latter has been extruded or coextruded or has already undergone a first stretching .

In the extrusion or coextrusion blow molding process, the film is extruded or 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 10 to 30, the inflation rate can range from 1 to 10 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. For the case where it is desired to carry out a very sensitive bi-stretching on the film, the extrusion or the coextrusion can be carried out by application of the "double bubble" process, the two "bubbles" of said process being carried out one after the other, usually continuous. EXAMPLE 1 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:

ABBREVIATION NATURE ORIGIN BRAND

PETG Polyethylene terephthalate glycol Eastman Eastar

(modified with 1, 4-cyclohexanedimethanol) 6763

MDPE BASF Lupolen 3220 K medium density polyethylene

HDPE High density polyethylene DSM Stamylex 9089F

Ethylene terpolymer / acrylic ester / maleic anhydride DuPont Bynel CXA 4033

AB Anti-blocking agent in the form of an Eastman C0047 masterbatch comprising 10% by weight of silica and 90% by weight of PETG from

brand Eastar 6763 11

The three layers of the film are described in this table

LAYER PERCENTAGE IN COMPOSITION (% BY WEIGHT) WEIGHT IN THE FILM

1st outer layer 20% 95% PETG + 5% AB inner layer 60% 50% MDPE + 30% HDPE + 20% terpolymer

2nd outer layer 20% 95% PETG + 5% AB

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

- draw rate: 20 - 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. A 60 mm x 90 mm rectangle is cut from the film and a candy is wrapped manually by making a foil by turning the film 1/2 of a time with one hand relative to the candy held by the other hand. We note that the foil does not show a marked tendency to go back. EXAMPLE 2 (comparative)

A rectangle of 60 mm x 90 mm is cut from a biaxially oriented polypropylene film and a candy is wrapped in the same manner as for Example 1. We can see that the foil has a marked tendency to go back.

Claims

12

R EV E N D I CATI O N S

7. An assembly comprising a solid and its packaging, said packaging comprising at least one film comprising at least one foil and / or a fold, said film comprising at least one layer comprising at least one polyester.

2. Assembly according to claim 1, characterized in that the packaging directly marries the major part of the surface of the packaged solid.

3. Assembly according to one of the preceding claims, characterized in that the solid is a food material and more particularly a candy.

Assembly according to one of the preceding claims, characterized in that the packaging is not held by any adhesive or glue, nor by any hot or cold sealing, or by any reinforcement coming in excess thickness to said film.

5. Assembly according to one of the preceding claims, characterized in that the film comprises at least one layer comprising at least one polyester which can be obtained from the condensation of terephthalic acid with ethylene glycol and a diol comprising at least three carbon atoms, said film being essentially monolayer or multilayer and comprising at least one layer comprising at least one polyolefin.

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

7. 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 applying both to the geometry and to the composition of said film. 13

8. Assembly according to one of the preceding claims, characterized in that the sum of the mass of the layers comprising the polyester represents at least 20% by weight of the mass of the film.

9. An assembly according to one of the preceding claims characterized in that the film comprises at least three layers, two of which comprise at least polyester and one of which comprising at least one polyolefin is in the middle.

10. Assembly according to the preceding claim, characterized in that the sum of the mass of the three layers constitutes at least 80% of the total mass of the film and in that each of said three layers constitutes at least 10% by weight of the total mass of the film. movie.

11. Assembly according to one of claims 9 or 10 characterized in that the middle layer comprises at least 60% of an ethylene polymer.

12. Assembly according to one of claims 9 to 1 1 characterized in that the middle layer represents 40 to 80% by weight of the mass of the film.

13. Assembly according to one of claims 5 to 12 characterized in that the diol is cyclohexane dimethanol.

14. Assembly according to the preceding claim, characterized in that the diacid component of the polyester comprises 70 to 100% by mole of terephthalic acid and 0 to 30% by mole of another acid chosen from isophthalic acid, naphthalenedicarboxylic acid , 1,4-cyclohexanedicarboxylic acid or mixtures thereof, and in that the diol component of the polyester comprises 2 to 99 mol% of 1,4-cyclohexanedimethanol and 1 to 98 mol% of ethylene glycol.

15. Assembly according to the preceding claim, characterized in that the diacid component of the polyester comprises 80 to 100% by mole of terephthalic acid and 0 to 20% by mole of isophthalic acid and in that the diol component of the polyester comprises 25 to 40% in 14 moles of 1,4-cyclohexanedimethanol and 75 to 60% by mole of ethylene glycol.

16. Assembly according to one of the preceding claims, characterized in that the film comprises at least one anti-blocking agent and / or at least one anti-static agent and / or at least one slip agent.

17. Assembly according to one of the preceding claims, characterized in that the film has undergone printing and / or metallization.

18. Assembly according to one of the preceding claims, characterized in that the film has a thickness of 10 to 60 μm.

19. Film comprising at least one layer comprising at least one polyester which can be obtained from the condensation of terephthalic acid with ethylene glycol and a diol comprising at least three carbon atoms, said film being essentially monolayer or multilayer and comprising at least minus one layer of polyolefin.

20. Film according to the preceding claim characterized in that the polyester is amorphous.

21. Film according to claim 19 or 20 characterized in that it comprises a plane of symmetry which is parallel to it, said symmetry applying both to the geometry and to the composition of said film.

22. Film according to one of claims 19 to 21, characterized in that the sum of the mass of the layers comprising the polyester represents at least 20% by weight of the mass of the film.

23. Film according to one of claims 19 to 22 characterized in that it comprises at least three layers, two of which comprise at least polyester and one of which comprising at least one polyolefin is in the middle.

24. Film according to the preceding claim, characterized in that the sum of the mass of the three layers constitutes at least 80% of the 15 total mass of the film and in that each of said three layers constitutes at least 10% by weight of the total mass of the film.

25. Film according to one of claims 23 or 24 characterized in that the middle layer comprises at least 60% of an ethylene polymer.

26. Film according to one of claims 23 to 25 characterized in that the middle layer represents 40 to 80% by weight of the mass of the

10 movie.

27. Film according to one of claims 19 to 26 characterized in that the diol is cyclohexane dimethanol.

28. Film according to the preceding claim, characterized in that the diacid component of the polyester comprises 70 to 100% by mole of terephthalic acid and 0 to 30% by mole of another acid chosen from isophthalic acid, the acid naphthalenedicarboxylic, 1,4-cyclohexanedicarboxylic acid or mixtures thereof, and in that the

The diol component of the polyester comprises 2 to 99 mol% of 1,4-cyclohexanedimethanol and 1 to 98 mol% of ethylene glycol.

29. Film according to the preceding claim, characterized in that the diacid component of the polyester comprises 80 to 100% by mole 25 of terephthalic acid and 0 to 20% by mole of isophthalic acid and in that the diol component of the polyester comprises 25 40% by mole of 1,4-cyclohexanedimethanol and 75 to 60% by mole of ethylene glycol.

30 30. Film according to one of claims 1 9 to 29 characterized in that it comprises at least one anti-blocking agent and / or at least one anti-static agent and / or at least one slip agent.

31. Film according to one of claims 19 to 30 characterized in that it has undergone printing and / or metallization.

32. Film according to one of claims 19 to 31 characterized in that it has a thickness of 10 to 60 μm. 16

33. A method of manufacturing a film of one of claims 19 to 32, characterized in that it comprises a step of extrusion or coextrusion blowing of the different thermoplastic compositions

5 from which the different layers of said film come.

34. Method according to the preceding claim, characterized in that the operating parameters of the blowing extrusion or coextrusion step are as follows:

10 - drawdown rate .... 2 to 50,

- inflation rate 1 to 10,

- air gap 0.5 to 5 mm

- pulling speed, 10 to 150 m / min

35 35. Method according to the preceding claim, characterized in that the operating parameters of the extrusion or coextrusion blow molding step are as follows:

- drawdown rate .... 10 to 30,

- inflation rate 1, 5 to 3, 20 - air gap 0.8 to 1.6 mm

- pulling speed 30 to 60 m / min

36. Method according to one of claims 33 to 35 characterized in that the extrusion or coextrusion blow molding step is followed by at least

25 a stretching or bi-stretching step.

37. Method according to one of claims 33 to 36 characterized in that the film undergoes at least one step of antistatic treatment and / or metallization and / or printing.