Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
  • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
  • B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C66/00—General aspects of processes or apparatus for joining preformed parts
  • B29C66/004—Preventing sticking together, e.g. of some areas of the parts to be joined
  • B29C66/0042—Preventing sticking together, e.g. of some areas of the parts to be joined of the joining tool and the parts to be joined
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C66/00—General aspects of processes or apparatus for joining preformed parts
  • B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
  • B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C66/00—General aspects of processes or apparatus for joining preformed parts
  • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
  • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C66/00—General aspects of processes or apparatus for joining preformed parts
  • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
  • B29C66/72—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined
  • B29C66/723—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the structure of the material of the parts to be joined being multi-layered
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C66/00—General aspects of processes or apparatus for joining preformed parts
  • B29C66/90—Measuring or controlling the joining process
  • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
  • B29C66/919—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux characterised by specific temperature, heat or thermal flux values or ranges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C66/00—General aspects of processes or apparatus for joining preformed parts
  • B29C66/90—Measuring or controlling the joining process
  • B29C66/92—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools
  • B29C66/929—Measuring or controlling the joining process by measuring or controlling the pressure, the force, the mechanical power or the displacement of the joining tools characterized by specific pressure, force, mechanical power or displacement values or ranges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C66/00—General aspects of processes or apparatus for joining preformed parts
  • B29C66/90—Measuring or controlling the joining process
  • B29C66/94—Measuring or controlling the joining process by measuring or controlling the time
  • B29C66/949—Measuring or controlling the joining process by measuring or controlling the time characterised by specific time values or ranges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/16—Layered products comprising a layer of synthetic resin specially treated, e.g. irradiated
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
  • B32B27/306—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl acetate or vinyl alcohol (co)polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/03—3 layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/05—5 or more layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/24—All layers being polymeric
  • B32B2250/246—All polymers belonging to those covered by groups B32B27/32 and B32B27/30
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/40—Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2255/00—Coating on the layer surface
  • B32B2255/10—Coating on the layer surface on synthetic resin layer or on natural or synthetic rubber layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/30—Properties of the layers or laminate having particular thermal properties
  • B32B2307/308—Heat stability
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
  • B32B2307/514—Oriented
  • B32B2307/516—Oriented mono-axially
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
  • B32B2307/514—Oriented
  • B32B2307/518—Oriented bi-axially
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
  • B32B2307/54—Yield strength; Tensile strength
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/72—Density
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/724—Permeability to gases, adsorption
  • B32B2307/7242—Non-permeable
  • B32B2307/7244—Oxygen barrier
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/724—Permeability to gases, adsorption
  • B32B2307/7242—Non-permeable
  • B32B2307/7246—Water vapor barrier
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/732—Dimensional properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2553/00—Packaging equipment or accessories not otherwise provided for

Definitions

• the present invention belongs to the field of products for packaging and more particularly to that of films intended to form packaging.
• the present invention relates to a stretch-oriented multilayer film and its preparation process.
• the packaging field uses many types of flexible films to produce different types of packaging. They can in particular be associated with rigid supports (trays, pots) or constitute all or part of the entire packaging.
• the films used can be monolayer, that is to say made up over their entire thickness by a single component or a single mixture of components.
• PE polyethylene films
• the films for packaging can be multilayered, that is to say that their thickness comprises several layers each consisting of a single component or a single component mixture. Mention may thus be made of polyamide (PA)/polyethylene (PE) or PA/polypropylene (PP) films. Each of the layers has different physico-chemical properties which will overlap and/or act in synergy to give the packaging the ideal characteristics for its use.
• PA polyamide
• PE polyethylene
• PP polypropylene
• the monolayer or multilayer film can be stretched to modify and improve its physical characteristics.
• the flexible film stretching process is a recognized process and subject to many developments.
• mono-axial stretching the film comes into contact with a certain number of heating rolls, then is stretched between two more or less close stretching rolls and is finally relaxed and cooled.
• This process is widely used in the implementation of polyolefins because after stretching, a polyethylene film sees its rigidity, transparency and its barrier properties improved.
• This process has also been carried out on multilayer films comprising layers forming a gas barrier made of ethylene polyvinyl alcohol (EVOH), polyamide or others.
• EVOH ethylene polyvinyl alcohol
• patent US007794848B2 shows that after stretching a multilayer film sees its barrier and mechanical properties greatly improved and this after a minimum stretching of 5 times in the machine direction.
• the stretched multilayer films can be used in association with other films with which they are associated by methods well known to those skilled in the art, such as hot calendering or rolling. This association can be made after the surface of the stretched multilayer film has served as the printing surface.
• the present invention proposes to provide a new stretched multilayer film having a high resistance to temperature both in terms of shrinkage and melting, while being recyclable and easy to laminate.
• the film according to the invention has a good barrier to O 2 and to water vapour.
• the multilayer film according to the invention can be used at high temperature and thus be used for products intended to be hot-packed and/or pasteurized.
• the temperature resistance of the film according to the invention makes it possible to associate it by welding with connectors which are often based on high density polyethylene which requires high temperatures to be welded.
• the present invention relates to a multilayer film remarkable in that it has on each of its faces an outer layer comprising ethylene polyvinyl alcohol (EVOH).
• EVOH ethylene polyvinyl alcohol
• said multilayer film further comprises at least: - a binder layer, and - a layer comprising polyethylene (PE), characterized in that said binder layer is inserted between said outer layer comprising ethylene polyvinyl alcohol (EVOH) and said layer comprising polyethylene (PE).
• PE polyethylene
• Ethylene vinyl alcohol is a component that makes it possible to obtain layers with oxygen barrier properties. Until now the layers of EVOH were systematically covered by a waterproof layer.
• the applicants have been able to show that the presence of an outer layer of EVOH made it possible to obtain films having greatly improved thermal resistance compared to a polyethylene film. Furthermore, the presence of a polar material on the surface of the film improves the resistance of surface treatments (metallization, AlOx, SiOx, etc.), printing processes, or even lamination processes, while giving the film good barrier properties.
• the term "external" is intended to mean that under normal conditions of use, said layer is not permanently covered on both sides but comprises a free face directly accessible from the outside. of said multilayer film.
• none of the outer layers comprising ethylene polyvinyl alcohol (EVOH) is covered, with the exception of the possible use of printing ink, permanently on both sides but comprises a free face directly accessible from the outside of said multilayer film.
• EVOH ethylene polyvinyl alcohol
• binder is intended to designate a product making it possible to permanently associate said outer layer comprising polyvinyl ethylene alcohol (EVOH) and said layer comprising polyethylene (PE).
• EVOH polyvinyl ethylene alcohol
• PE polyethylene
• the multilayer film according to the invention comprises: a first outer layer comprising ethylene polyvinyl alcohol (EVOH) combined with, a first layer of binder associated with, a first layer of polyethylene (PE), a second layer of polyethylene (PE) combined with, a second layer of binder associated with, a second outer layer comprising ethylene polyvinyl alcohol (EVOH).
• EVOH ethylene polyvinyl alcohol
• association is intended to mean that the two associated layers are in direct contact.
• the multilayer film according to the invention further comprises at least one additional layer between said first layer of polyethylene (PE) and said second layer of polyethylene (PE).
• said additional layer consists of plastomer.
• the multilayer film according to the invention consists of five successive layers: a first outer layer comprising ethylene polyvinyl alcohol (EVOH), a first layer of binder, a layer of polyethylene (PE), a second layer of binder, a second outer layer comprising ethylene polyvinyl alcohol (EVOH).
• a first outer layer comprising ethylene polyvinyl alcohol (EVOH)
• a first layer of binder comprising ethylene polyvinyl alcohol (EVOH)
• PE polyethylene
• PE polyethylene
• EVOH ethylene polyvinyl alcohol
• said multilayer film according to the invention has on each of its faces an outer layer comprising ethylene polyvinyl alcohol (EVOH).
• EVOH ethylene polyvinyl alcohol
• Symmetrical films have the advantage of being insensitive to the phenomenon of curling (the English term “curling” is more commonly used) and are therefore perfectly flat.
• said outer layer comprising ethylene polyvinyl alcohol (EVOH) comprises between 24% molar and 48% molar ethylene.
• said outer layer comprising ethylene polyvinyl alcohol (EVOH) comprises between 29% molar and 38% molar ethylene.
• said outer layer comprising ethylene polyvinyl alcohol (EVOH) consists of a resin chosen from the group consisting of EVAL® L171B, EVAL® XEP 1435B, EVAL® SP521B, EVAL® XEP 1385 , EVAL® XEP 1385B, EVAL® F101B, EVAL® F171B, EVAL® T101B, EVAL® J171B, EVAL® SP482B, EVAL® H171B, EVAL® E105B, EVAL® SP292B and EVAL® E171B.
• the binder layer preferably comprises a polyethylene/EVOH binder and even more preferably a polyethylene grafted with maleic anhydride.
• the binder layer 3 preferably consists of a polyethylene/EVOH binder and even more preferably of a polyethylene grafted with maleic anhydride.
• Polyethylene/EVOH binders and polyethylenes grafted with maleic anhydride are well known to those skilled in the art. These include OREVAC® 18360, OVERAC ® 18300, OVERAC ® 18301, OVERAC ® 18362 and OVERAC® 18363.
• said layer comprising polyethylene (PE) has a density of between 0.900 and 0.962 g/cm 3 .
• said layer comprising polyethylene (PE) has a density of between 0.918 and 0.940 g/cm 3 .
• the multilayer film according to the invention is produced by flat die coextrusion, inflation coextrusion or by lamination.
• the inflation coextrusion process is more particularly preferred.
• This technique is well known to those skilled in the art, it consists of coextruding a sheath of material through an annular die. This sheath is then pinched and inflated with a gas. Under the combined action of stretching and inflation, a bubble-shaped film is formed. This swollen film is cooled and then flattened. A film is therefore obtained in the form of a sheath that can be split, to obtain two equivalent flat films, before carrying out the subsequent stretching steps. Alternatively, it is possible not to split this sheath which will allow obtaining a symmetrical film.
• this sheath is composed of a material capable of adhering to itself, a symmetrical product will be obtained known as a "bonded sheath".
• materials capable of adhering to itself mention may in particular be made of polymers with a low melting point and preferably PEs with a low melting point.
• the so-called "glued sheath" process is particularly preferred for producing the multilayer film according to the invention.
• the multilayer film according to the invention has a thickness of between 40 and 200 ⁇ m
• the multilayer film according to the invention has a thickness of between 50 and 150 ⁇ m.
• the present invention also relates to a method for preparing a stretched film, characterized in that it comprises:
• - a step consisting in stretching in at least one direction the film provided in the previous step at a temperature of at least 90° C. until the thickness of the stretched film obtained is less than 60 ⁇ m and preferentially 50 ⁇ m.
• the present invention also relates to a stretched film obtained by the process according to the invention.
• the degree of stretching practiced in the method according to the invention is between 3 and 10 and even more preferentially between 4 and 6.
• said stretched film according to the invention has a modulus of rigidity at least equal to 500 MPa.
• modulus of rigidity refers to a measurement carried out according to the ISO-527 standard.
• said stretched film according to the invention has a vapor barrier value of less than 10 g/m2/d.
• vapour barrier value refers to a measurement carried out according to standard ASTM E398.
• said stretched film according to the invention has an oxygen barrier value of less than 2 cm3/m2/d.
• oxygen barrier value refers to a measurement carried out according to standard ASTM D3985 .
• the step consisting in stretching said multilayer film consists in stretching said film in a single direction.
• the step consisting in stretching said multilayer film consists in stretching said film in two directions and even more preferentially in two directions orthogonal with respect to each other.
• the method according to the invention further comprises a surface treatment step, subsequent to the step consisting in stretching the film, chosen from the group consisting of corona treatment, vacuum plasma treatment, atmospheric plasma processing, coating, gravure printing, flexogravure printing, rotogravure printing, physical vapor deposition, chemical vapor deposition, plasma assisted chemical vapor deposition.
• a surface treatment step subsequent to the step consisting in stretching the film, chosen from the group consisting of corona treatment, vacuum plasma treatment, atmospheric plasma processing, coating, gravure printing, flexogravure printing, rotogravure printing, physical vapor deposition, chemical vapor deposition, plasma assisted chemical vapor deposition.
• the final film, obtained after any one of these various operations, comprising the stretched film according to the invention comprises less than 10% by weight of EVOH and even more preferably less than 5% mass of EVOH.
• the present invention also relates to a film comprising the stretched film according to the invention, characterized in that it comprises less than 10% by weight of EVOH and even more preferably less than 5% by weight of EVOH.
• This type of film has significant recyclability properties.
• the present invention also relates to a packaging comprising a film according to the invention characterized in that said film is not associated on the whole of at least one of its external surfaces with another component of said packaging.
• said film is not associated on all of its external surfaces with another component of said packaging.
• the packaging according to the invention may take different forms, according to a preferred embodiment said packaging will be a sachet or a flexible lid for a tray and even more preferably a sachet entirely consisting of a film according to the invention. Quite preferably, the packaging according to the invention is a Flowpack sachet entirely consisting of a film according to the invention.
• the present invention also relates to the use of packaging for packaging a product intended to be pasteurized in said packaging.
• the present invention also relates to a process for pasteurizing a food comprising the steps consisting in: - packaging said food in a packaging according to the invention, - close said packaging tightly, - incubating said food in said packaging at a temperature between 75°C and 95°C for a period of 30 to 180 min.
• the present invention also relates to a process for the hot packaging of a food characterized in that it comprises the steps consisting in: - conditioning said food at a temperature between 70 and 90°C, - close said packaging tightly.
• a preferred embodiment of the invention is a multilayer film 1 consisting of five successive layers:
• a first outer layer 2 comprising ethylene polyvinyl alcohol (EVOH),
• EVOH ethylene polyvinyl alcohol
• PE polyethylene
• a second outer layer 2 comprising ethylene polyvinyl alcohol (EVOH).
• EVOH ethylene polyvinyl alcohol
• said outer layer 2 comprising ethylene polyvinyl alcohol (EVOH) comprises between 10% and 35%, preferentially between 24% and 48% and even more preferentially between 29% and 38 % ethylene.
• the outer layer 2 comprising polyvinyl ethylene alcohol (EVOH) preferably consists of EVAL® J171B or EVAL® H171B.
• the embodiment presented in preferably has a thickness of between 40 and 200 ⁇ m and even more preferably between 50 and 150 ⁇ m.
• each outer layer 2 has a thickness of between 5 and 20% of the total thickness of the film
• each binder layer 3 has a thickness of between 5 and 15%
• each polyethylene layer 4 has a thickness of between 20 and 80% of the total film thickness.
• Said multilayer film is obtained by inflation extrusion followed by a stretching step. Prior to this last step, the multilayer film is preheated homogeneously to a temperature slightly lower than the melting temperature of the film.
• the stretching phase is performed between two cylinders, one rotating at the same speed as the heating cylinders and one at a higher speed (2 to 10 X).
• the stretching phase is preferably followed by a relaxation phase carried out between rollers whose temperature is equal to or slightly lower than the preheating temperature.
• the relaxation phase is preferentially followed by a cooling phase at room temperature.
• the stretched film is then preferably stored in the form of reels.
• a multilayer film according to the invention was prepared using the inflation coextrusion technique. Before stretching, said film has the following consecutive layers: 7.5%EVOH 10% binder 22.5% EP 20% Plastomer 22.5% EP 10% binder 7.5% EVOH.
• the percentages mentioned above refer to the thickness of each layer compared to the total thickness of the multilayer film.
• the multilayer film was then stretched 4.8x at a temperature between 115 and 125°C in the machine direction to reach a thickness of 40 ⁇ m.
• the multilayer film was also subjected to welding tests, at temperatures between 130 and 160°C, between two bars with 2bar of pressure and holding the temperature for 0.5 seconds.
• the multilayer film was also subjected to a heat shrinkage test.
• a disk 10 cm in diameter was cut from the stretched film and subjected to a temperature of 120° C. for 1 min. At the end of this step, the ribs of the disc are remeasured and the percentages of retraction calculated.
• the surface tension of the multilayer film was determined by an angle measurement test of a drop on the surface of the film.
• the polarity is deduced from the use of different liquids.
• the excellent temperature resistance of the film according to the invention makes it possible to use it for the packaging of hot products or products to undergo a pasteurization step after packaging.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Laminated Bodies (AREA)
• Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
• Wrappers (AREA)

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• 2020
  • 2020-09-10 FR FR2009170A patent/FR3113859A1/fr active Pending
• 2021
  • 2021-09-09 WO PCT/EP2021/074860 patent/WO2022053581A1/fr not_active Ceased
  • 2021-09-09 EP EP21773611.5A patent/EP4210941A1/de not_active Withdrawn

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