Patent Description:
Polyethylene based films are widely used everywhere in daily life, like packaging, due to their excellent cost / performance ratios. These films must obviously protect the contents of the package from damage and the environment.

However, due to increasing demands on the needs of the films, multilayer packaging is typically employed utilising different types of polymers.

One classical combination are polyester (e.g. PET)-polyolefin (PO) laminates. The PO is used for the sealing layer and the polyester triggers the mechanical and thermal residence. Such kind of structure served the needs in the last years, but although these structures can offer attractive properties, the recycling of such materials is difficult. Therefore, making the materials pure is preferred. In that manner, a packaging with 'mono-materials' is really appreciated.

In order to simplify the recycling process, purer materials (i.e. based on same kind of polymers) are required, meaning that the content of "contamination" (i.e. different polymer) needs to be below <NUM> wt%.

However, this imposes higher requirements on the performance of materials themselves. There is thus a need to produce multilayer films, which offer the opportunity for facile recycling, together with an attractive balance of properties, e.g. a multilayered material with balanced sealing, stiffness, toughness is highly desirable.

Different solutions are already known in the prior art.

<CIT> relates to multilayer films comprising at least one layer (A), being a sealing layer, and one layer (B), with beneficial heat sealing and hot tack properties.

<CIT> relates to heat sealable compositions suitable for film and film structures comprising: (a) from <NUM> to <NUM> wt% of a low melting polymer comprising an ethylene based copolymer having a density of from <NUM>/cm<NUM> to <NUM>/cm<NUM>, a melt index of from <NUM> dg/min to <NUM> dg/min, a molecular weight distribution of no greater than <NUM>, and a composition distribution breath index greater than <NUM> percent; and, (b), being different from (a), from <NUM> to <NUM> weight percent of a propylene based polymer having from <NUM> mol% to <NUM> mol% propylene and from <NUM> mol% to <NUM> mol% of an alpha-olefin other than propylene.

<CIT> relates to a sealant composition, a method of producing the same, articles made therefrom, and a method for forming such articles. The sealant composition according to <CIT> comprises: (a) from <NUM> to <NUM> wt% of an ethylene/alpha-olefin interpolymer composition, based on the total weight of the sealant composition, wherein said ethylene/alpha-olefin interpolymer composition comprises an ethylene/alpha-olefin interpolymer, the ethylene/alpha-olefin interpolymer having a Comonomer Distribution Constant (CDC) in the range of from <NUM> to <NUM>, and a density in the range of from <NUM> to <NUM>/cm<NUM>, a melt index (I2) in a range of from <NUM> to <NUM>/<NUM> minutes, and long chain branching frequency in the range of from <NUM> to <NUM> long chain branches (LCB) per 1000C; (b) from <NUM> to <NUM> wt% of a propylene/alpha-olefin interpolymer composition, wherein said propylene/alpha-olefin interpolymer composition comprises a propylene/alpha-olefin copolymer or a propylene/ethylene/butene terpolymer, wherein said propylene/alpha-olefin copolymer has a crystallinity in the range of from <NUM> wt% to <NUM> wt%, a heat of fusion in the range of from <NUM> Joules/gram to <NUM> Joules/gram, and a DSC melting point in the range of <NUM> to <NUM>.

<CIT> discloses multilayer film laminate which comprises a multilayer film with, in the given layer order, an inner layer (A), a core layer (B) and an outer layer (C), which is laminated to a substrate.

The inner layer (A) comprises a multimodal polyethylene composition, i.e. a bimodal linear low density polyethylene (LLDPE), having a density of <NUM>/m<NUM> or less, a molecular weight distribution Mw/Mn of at least <NUM> and a MFR<NUM> of <NUM> to <NUM>/<NUM> when determined according to ISO <NUM> (at <NUM> and <NUM> load).

Preferably, the LLDPE comprises an ethylene-<NUM>-hexene copolymer, ethylene-<NUM>-octene copolymer or ethylene-<NUM>-butene copolymer.

Layer (C) comprises a LLDPE, which can be an unimodal or multimodal LLDPE. Moreover, the LLDPE can be znLLDPE or the LLDPE can be obtained by polymerization using a metallocene catalyst (mLLDPE). Both mLLDPE and znLLDPE alternatives are preferable. Also preferably, layer (C) may comprise a low-density polyethylene (LDPE) homo- or copolymer composition obtained by high-pressure polymerization.

Layer (B) can comprise or consists of the same polymer composition as used in layer (A) or layer (C).

Borstar® FB2310 or Borstar® FB2230 as commercial grades of LLDPE's are given as examples as feasible multimodal LLDPE grades for at least layer (A) and, if present, for optional layer(s), such as layer (B).

Film properties, like sealing initiation temperature (SIT) or hot tack force are not mentioned at all.

<CIT> discloses a <NUM>-layer structure, wherein the outer layers comprise LLDPE, preferably unimodal LLDPE, especially unimodal mLLDPE. The LLDPE is preferably a C2/C6-copolymer. One or both outer layers may contain LDPE.

It is further disclosed, that a specific film may comprise a first outer layer comprising a unimodal LLDPE and LDPE blend with the other outer layer being formed from multimodal LLDPE optionally combined with an LDPE component.

The core layer comprises a multimodal polyethylene component having a lower molecular weight component and a higher molecular weight component, i.e. a multimodal LLDPE.

Thus, the multimodal PE comprises a higher molecular weight component, which preferably corresponds to an ethylene copolymer and a lower molecular weight component, which corresponds to an ethylene homopolymer or copolymer. Such <NUM>-layer films are especially suitable for producing pouches.

For packaging companies it is of utmost importance to reduce the sealing initiation temperature (SIT) of a packaging film. Even more in the view of a sustainable and circular approach, low sealing temperature and higher hot tack force (HTF) are required. Lower SIT and higher HTF allows running the packaging lines faster and/or at lower temperatures, thus saving costs and energy.

Starting therefrom it was an objective of the present invention to provide multilayer films having a low SIT as well as a higher HTF than the multilayer films known from the prior art.

Such multilayered film should be furthermore easy to recycle and in addition have very good mechanical properties and acceptable optical properties.

These objects have been solved by the multilayered film according to claim <NUM> comprising.

Advantageous embodiments of the multilayered film in accordance with the present invention are specified in the dependent claims <NUM> to <NUM>. The present invention further relates in accordance with claim <NUM> to the use of the film according to the present invention as packaging material.

A metallocene-catalysed (linear low density) polyethylene is defined in this invention as a (linear low density) polyethylene copolymer, which has been produced in the presence of a metallocene catalyst.

Ziegler-Natta catalysed linear low density polyethylene (znLLDPE) is defined in this invention as linear low density polyethylene copolymer, which has been produced in the presence of a Ziegler-Natta catalyst.

Polyethylene copolymers made using single site catalysis, as opposed to Ziegler Natta catalysis, have characteristic features that allow them to be distinguished from Ziegler Natta materials. In particular, the comonomer distribution is more homogeneous. This can be shown using TREF or Crystaf techniques. Catalyst residues may also indicate the catalyst used. Ziegler Natta catalysts would not contain a Zr or Hf group (IV) metal for example.

For the purpose of the present invention the metallocene-catalysed (linear low density) polyethylene consisting of an in-situ blend of an ethylene-<NUM>-butene polymer component (A) and an ethylene-<NUM>-hexene polymer component (B) means that the polymer is produced in an at least <NUM>-stage sequential polymerization process, wherein first component (A) is produced and component (B) is then produced in the presence of component (A) in a subsequent polymerization step, yielding the metallocene-catalysed (linear low density) polyethylene or vice versa, i.e. first component (B) is produced and component (A) is then produced in the presence of component (B) in a subsequent polymerization step, yielding the metallocene-catalysed (linear low density) polyethylene.

The same is true for the znLLDPE or HDPE used in the present invention.

The term "multimodal" in context of multimodal metallocene-catalysed (linear low density) polyethylene means herein multimodality with respect to melt flow rate (MFR) of at least the ethylene polymer components (A) and (B), i.e. the ethylene polymer components (A) and (B), have different MFR values. The multimodal metallocene-catalysed (linear low density) polyethylene can have further multimodality between the ethylene polymer components (A) and (B) with respect to one or more further properties, like density, comonomer type and/or comonomer content, as will be described later below.

The same is true for multimodal, e.g. bimodal or trimodal, znLLDPE or HDPE used in the present invention.

An ethylene homopolymer is a polymer that essentially consists of ethylene monomer units. Due to impurities especially during commercial polymerization processes, an ethylene homopolymer can comprise up to <NUM> mol% comonomer units, preferably up to <NUM> mol% comonomer units and most preferably up to <NUM> mol% comonomer units.

Where the term "comprising" is used in the present description and claims, it does not exclude other non-specified elements of major or minor functional importance. For the purposes of the present invention, the term "consisting of" is considered to be a preferred embodiment of the term "comprising of". If hereinafter a group is defined to comprise at least a certain number of embodiments, this is also to be understood to disclose a group, which preferably consists only of these embodiments.

For the purpose of the present invention the term "consists of an in-situ blend of (i) and (ii)" does not exclude the presence of any additive, which may be added to the MMCP. It only refers to the number of polymer components, i.e. polymer component (A) and polymer component (B).

The sealing layer of the multilayered film according to the present invention comprises a specific metallocene-catalysed multimodal polyethylene copolymer (MMCP). The other layers may also comprise said copolymer (MMCP).

The metallocene-catalysed multimodal polyethylene copolymer (MMCP) consists of an in-situ blend of (i) <NUM> to <NUM> wt% of an ethylene-<NUM>-butene polymer component (A), and (ii) <NUM> to <NUM> wt% of an ethylene-<NUM>-hexene polymer component (B).

The ethylene-<NUM>-butene polymer component (A) has a density (ISO <NUM>) in the range of <NUM> to <NUM>/m<NUM> and a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>.

The ethylene-<NUM>-hexene polymer component (B) has a density (ISO <NUM>) in the range of <NUM> to <NUM>/m<NUM> and a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>.

The metallocene-catalysed multimodal polyethylene copolymer (MMCP) has a density (ISO1183) in the range of <NUM> to <NUM>/m<NUM>, a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM> and a ratio of the MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) to MFR<NUM> (<NUM>, <NUM>, ISO <NUM>), MFR<NUM>/MFR<NUM>, in the range of <NUM> to <NUM>.

In a preferred embodiment of the present invention, the ethylene-<NUM>-butene polymer component (A) consists of ethylene polymer fractions (A-<NUM>) and (A-<NUM>).

It is possible that fraction (A-<NUM>) is produced first and then fraction (A-<NUM>) is produced in the presence of fraction (A-<NUM>) in a subsequent reactor or vice versa, i.e. fraction (A-<NUM>) is produced first and then fraction (A-<NUM>) is produced in the presence of fraction (A-<NUM>) in a subsequent reactor. Preferably fraction (A-<NUM>) is produced first.

In case that the ethylene-<NUM>-butene polymer component (A) consists of ethylene polymer fractions (A-<NUM>) and (A-<NUM>), the MFR<NUM> of the ethylene polymer fractions (A-<NUM>) and (A-<NUM>) may be different from each other or may be the same, preferably the are different from each other.

Thus, the ethylene polymer fractions (A-<NUM>) and (A-<NUM>) have a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>, preferably of <NUM> to <NUM>/<NUM>, more preferably of <NUM> to <NUM>/<NUM> and even more preferably of <NUM> to <NUM>/<NUM>, like <NUM> to <NUM>/<NUM>.

The MFR<NUM> of the ethylene polymer components (A) and (B) are different from each other.

The ethylene polymer component (A) has a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>, preferably of <NUM> to <NUM>/<NUM>, more preferably of <NUM> to <NUM>/<NUM>, even more preferably of <NUM> to <NUM>/<NUM> and still more preferably of <NUM> to <NUM>/<NUM>.

The ethylene polymer component (B) has a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>, preferably of <NUM> to <NUM>/<NUM>, more preferably of <NUM> to <NUM>/<NUM> and even more preferably of <NUM> to <NUM>/<NUM>.

In an embodiment of the invention it is preferred the ratio of the MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of the ethylene-<NUM>-butene polymer component (A) to the MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of the final multimodal metallocene catalysed linear low density polyethylene (MMCP) is at least <NUM> to <NUM>, preferably <NUM> to <NUM>, more preferably of <NUM> to <NUM> and even more preferably of <NUM> to <NUM>.

The MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of the multimodal copolymer (MMCP) is in the range of <NUM> to <NUM>/<NUM>, preferably <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM> and even more preferably of <NUM> to <NUM>/<NUM>.

The multimodal copolymer (MMCP) has a ratio of the MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) to MFR<NUM> (<NUM>, <NUM>, ISO <NUM>), MFR<NUM>/MFR<NUM>, in the range of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM> and still more preferably from <NUM> to <NUM>.

Naturally, in addition to multimodality with respect to, i.e. difference between, the MFR<NUM> of ethylene polymer components (A) and (B), the multimodal PE of the invention can also be multimodal e.g. with respect to one or both of the two further properties: multimodality with respect to, i.e. difference between, the comonomer content(s) present in the ethylene polymer components (A) and (B); and/or the density of the ethylene polymer components (A) and (B).

Preferably, the multimodal copolymer (MMCP) is further multimodal with respect to the comonomer content of the ethylene polymer components (A) and (B).

The comonomer type for the polymer fractions (A-<NUM>) and (A-<NUM>) is the same, thus both fractions therefore have <NUM>-butene as comonomer.

The comonomer content of component (A) and (B) can be measured, or, in case, and preferably, one of the components is produced first and the other thereafter in the presence of the first produced in a so called multistage process, then the comonomer content of the first produced component, e.g. component (A), can be measured and the comonomer content of the other component, e.g. component (B), can be calculated according to following equation: <MAT>.

Even more preferably the multimodal polymer (MMCP) of the invention is further multimodal with respect to difference in density between the ethylene polymer component (A) and ethylene polymer component (B). Preferably, the density of ethylene polymer component (A) is different, preferably higher, than the density of the ethylene polymer component (B).

The density of the ethylene polymer component (A) is in the range of <NUM> to <NUM>/m<NUM>, preferably of <NUM> to <NUM>/m<NUM>, more preferably <NUM> to <NUM>/m<NUM> and/or the density of the ethylene polymer component (B) is in the range of <NUM> to <NUM>/m<NUM>, preferably of <NUM> to <NUM>/m<NUM> and more preferably of <NUM> to <NUM>/m<NUM>.

The polymer fractions (A-<NUM>) and (A-<NUM>) have a density in the range of from <NUM> to <NUM>/m<NUM>, preferably of <NUM> to <NUM>/m<NUM>, more preferably of <NUM> to <NUM>/m<NUM>, and most preferred <NUM> to <NUM>/m<NUM>.

The density of polymer fraction (A-<NUM>) and (A-<NUM>) may be the same or may be different from each other.

The metallocene catalysed multimodal copolymer (MMCP) is preferably a linear low density polyethylene (LLDPE) which has a well-known meaning.

The density of the multimodal copolymer (MMCP) is in the range of <NUM> to <NUM>/m<NUM>, preferably of <NUM> to <NUM>/m<NUM> and more preferably of <NUM> to <NUM>/m<NUM>.

More preferably the multimodal copolymer (MMCP) is multimodal at least with respect to, i.e. has a difference between, the MFR<NUM>, the comonomer content as well as with respect to, i.e. has a difference between the density of the ethylene polymer components, (A) and (B), as defined above, below or in the claims including any of the preferable ranges or embodiments of the polymer composition.

It is within the scope of the invention, that the first and the second ethylene polymer fraction (A-<NUM> and A-<NUM>) of the ethylene polymer component (A) are present in a weight ratio of <NUM>:<NUM> up to <NUM>:<NUM>, such as <NUM>:<NUM> to <NUM>:<NUM>, or <NUM>:<NUM> to <NUM>:<NUM>, or <NUM>:<NUM>.

The ethylene polymer component (A) is present in an amount of <NUM> to <NUM> wt% based on the multimodal copolymer (MMCP), preferably in an amount of <NUM> to <NUM> wt% and even more preferably in an amount of <NUM> to <NUM> wt%.

Thus, the ethylene polymer component (B) is present in an amount of <NUM> to <NUM> wt% based on the multimodal copolymer (MMCP), preferably in an amount of <NUM> to <NUM> wt% and more preferably in an amount of <NUM> to <NUM> wt%.

The metallocene-catalysed multimodal copolymer (MMCP) can be produced in a <NUM>-stage process, preferably comprising a slurry reactor (loop reactor), whereby the slurry (loop) reactor is connected in series to a gas phase reactor (GPR), whereby either ethylene component (A) or ethylene component (B) is produced in the loop reactor and the other ethylene polymer component is then produced in GPR in the presence of the first produced ethylene polymer component to produce the metallocene-catalysed multimodal copolymer (MMCP), preferably the ethylene polymer component (A) is produced in the loop reactor and the ethylene polymer component (B) is produced in GPR in the presence of the ethylene polymer component (A) to produce the metallocene-catalysed multimodal copolymer (MMCP).

In case that the ethylene component (A) of the metallocene-catalysed multimodal copolymer (MMCP) consists of ethylene polymer fractions (A-<NUM>) and (A-<NUM>), the metallocene-catalysed multimodal copolymer (MMCP) can be produced with a <NUM>-stage process, preferably comprising a first slurry reactor (loop reactor <NUM>), whereby the first slurry loop reactor is connected in series with another slurry reactor (loop reactor <NUM>), so that the first ethylene polymer fraction (A-<NUM>) produced in the loop reactor <NUM> is fed to the loop reactor <NUM>, wherein the second ethylene polymer fraction (A-<NUM>) is produced in the presence of the first fraction (A-<NUM>). It is possible that fraction (A-<NUM>) is produced first and then fraction (A-<NUM>) is produced in the presence of fraction (A-<NUM>) in a subsequent reactor or vice versa, i.e. fraction (A-<NUM>) is produced first and then fraction (A-<NUM>) is produced in the presence of fraction (A-<NUM>) in a subsequent reactor. Preferably fraction (A-<NUM>) is produced first.

The loop reactor <NUM> is thereby connected in series to a gas phase reactor (GPR), so that the first ethylene polymer component (A) leaving the second slurry reactor is fed to the GPR to produce a trimodal polyethylene copolymer. In this case, the reaction conditions in the two slurry reactors are chosen in a way that in the two slurry reactors different products in view of MFR and/or density are produced.

Such a process is described inter alia in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>. Full details of how to prepare suitable metallocene-catalysed multimodal copolymer (MMCP) can be found in these references.

The metallocene-catalysed multimodal copolymer (MMCP) according to the present invention is therefore preferably produced in a loop loop gas cascade. Such polymerization steps may be preceded by a prepolymerization step. The purpose of the prepolymerization is to polymerize a small amount of polymer onto the catalyst at a low temperature and/or a low monomer concentration. By prepolymerization it is possible to improve the performance of the catalyst in slurry and/or modify the properties of the final polymer. The prepolymerization step is preferably conducted in slurry.

The catalyst components are preferably all introduced to the prepolymerization step when a prepolymerization step is present. However, where the solid catalyst component and the cocatalyst can be fed separately it is possible that only a part of the cocatalyst is introduced into the prepolymerization stage and the remaining part into subsequent polymerization stages. Also in such cases it is necessary to introduce so much cocatalyst into the prepolymerization stage that a sufficient polymerization reaction is obtained therein.

It is understood within the scope of the invention, that the amount or polymer produced in the prepolymerization lies within <NUM> to <NUM> wt% in respect to the final metallocene-catalysed multimodal copolymer (MMCP). This can counted as part of the first ethylene polymer component (A).

The metallocene-catalysed multimodal copolymer (MMCP) is produced by using a metallocene catalyst. The metallocene catalyst preferably comprises a metallocene complex and a cocatalyst. The metallocene compound or complex is referred herein also as organometallic compound (C).

The organometallic compound (C) comprises a transition metal (M) of Group <NUM> to <NUM> of the Periodic Table (IUPAC <NUM>) or of an actinide or lanthanide.

The term "an organometallic compound (C)" in accordance with the present invention includes any metallocene or non-metallocene compound of a transition metal, which bears at least one organic (coordination) ligand and exhibits the catalytic activity alone or together with a cocatalyst. The transition metal compounds are well known in the art and the present invention covers compounds of metals from Group <NUM> to <NUM>, e.g. Group <NUM> to <NUM>, or <NUM> to <NUM>, such as Group <NUM> to <NUM> of the Periodic Table, (IUPAC <NUM>), as well as lanthanides or actinides.

In an embodiment, the organometallic compound (C) has the following formula (I):
<CHM>.

Preferably, the compound of formula (I) has the structure (I')
<CHM>.

Highly preferred complexes of formula (I) are
<CHM>
<CHM>.

Most preferably the complex dimethylsilanediylbis-[<NUM>-(<NUM>-trimethylsilylfuran-<NUM>-yl)-<NUM>,<NUM>-dimethylcyclopentadien-<NUM>-yl] zirconium dichloride is used.

More preferably the ethylene polymer components (A) and (B) of the multimodal copolymer (MMCP) are produced using, i.e. in the presence of, the same metallocene catalyst.

To form a catalyst, a cocatalyst, also known as an activator, is used, as is well known in the art. Cocatalysts comprising Al or B are well known and can be used here. The use of aluminoxanes (e.g. MAO) and/or boron based cocatalysts (such as borates) is preferred.

The multimodal copolymer (MMCP) may contain additives and/or fillers. The optional additives and fillers and the used amounts thereof are conventional in the field of film applications. Examples of such additives are, among others, antioxidants, process stabilizers, UV-stabilizers, pigments, fillers, antistatic additives, antiblock agents, nucleating agents, acid scavengers as well as polymer processing agent (PPA).

It is understood herein that any of the additives and/or fillers can optionally be added in so-called master batch, which comprises the respective additive(s) together with a carrier polymer, whereby the carrier polymer is calculated to the amount of the respective additive(s), based on the total amount of the multimodal copolymer (MMCP) (<NUM> wt%).

The sealing layer of the multilayered film according to the present invention comprises in addition to the MMCP a specific elastomer.

The sealing layer comprises <NUM> to <NUM> wt% based on the total weight of the sealing layer (SL) of an elastomer being a terpolymer of propylene, ethylene and <NUM>-butene; having.

Preferred ranges for the above cited properties are:.

According to a preferred embodiment in accordance with the present invention the elastomer has in addition a glass transition temperature determined by dynamic mechanical analysis according to ISO <NUM>- below -<NUM>, more preferably in the range of -<NUM> to below -<NUM>, still preferably in the range of -<NUM> to -<NUM>, like in the range of -<NUM> to -<NUM>.

The elastomers in accordance with the present invention are commercially available, e.g. from Mitsui under the tradename Tafmer™ PN, former Notio™ (such as e.g. Tafmer™ PN-<NUM>, Tafmer™ PN-<NUM>).

Components (a) and (b) sum up to <NUM> wt% in the sealing layer (SL) of the present invention.

The sealing layer (SL) forms <NUM> to <NUM> % of the total thickness of the multilayered film.

Thus, the elastomer (b) is present of no more than <NUM> wt% in total, based on the multilayered film, which simplifies recycling of the multilayered film.

According to a preferred embodiment in accordance with the present invention the content of MMCP (a) in the sealing layer (SL) based on the total weight of said layer is in the range of <NUM> to <NUM> wt%, more preferably in the range of <NUM> to <NUM> wt% and the content of elastomer (b) in the sealing layer (SL) based on the total weight of said layer is in the range of <NUM> to <NUM> wt%, more preferably in the range of <NUM> to <NUM> wt%.

A preferred embodiment of the multilayered film in accordance with the present invention stipulates that the skin layer (SKL) of the multilayered film has a thickness in the range of <NUM> to <NUM>, preferably in the range of <NUM> to <NUM> and more preferably in the range of <NUM> to <NUM>.

According to another preferred embodiment in accordance with the present invention the core layer (CL) of the multilayered film has a thickness in the range of <NUM> to <NUM>, preferably in the range of <NUM> to <NUM> and more preferably in the range of <NUM> to <NUM>.

In still another preferred embodiment according to the present invention the sealing layer (SL) of the multilayered film has a thickness in the range of <NUM> to <NUM>, preferably in the range of <NUM> to <NUM> and more preferably in the range of <NUM> to <NUM>.

In a further preferred embodiment according to the present invention the multilayered film has a total thickness in the range of <NUM> to <NUM>, preferably in the range of <NUM> to <NUM> and more preferably in the range of <NUM> to <NUM>.

For the three-layer structure, the sealing layer (SL), the skin layer (SKL) and the core layer (CL) may all be of equal thickness or alternatively the core layer (CL) may be thicker than the skin layer (SKL) and the sealing layer (SL).

A convenient film comprises a skin (SKL) and a sealing layer (SL), each forming <NUM> to <NUM>%, preferably <NUM> to <NUM>%, more preferably <NUM> to <NUM>% of the total final thickness of the <NUM>-layered film, the core layer (CL) forming the remaining thickness, e.g. <NUM> to <NUM>%, preferably <NUM> to <NUM>%, more preferably <NUM> to <NUM>% of the total final thickness of the <NUM>-layered film.

The total thickness of the film is <NUM>%, thus the sum of the individual layers has to be <NUM>%.

According to another preferred embodiment in accordance with the present invention the multilayered film consists of the skin layer (SKL), the core layer (CL) and the sealing layer (SL).

It is self-explanatory that the core layer (CL) is placed between the skin layer (SKL) and the sealing layer (SL).

The skin layer (SKL) preferably comprises <NUM> to <NUM> wt%, more preferably <NUM> to <NUM> wt%, still more preferably <NUM> to <NUM> wt% based on the total weight of the skin layer (SKL) and most preferably consists of a high density polyethylene (HDPE) and optionally <NUM> to <NUM> wt%, preferably <NUM> to <NUM> wt%, more preferably <NUM> to <NUM> wt% based on the total weight of the skin layer (SKL) of a LDPE having a density (ISO <NUM>) in the range of <NUM> to <NUM>/m<NUM>, preferably of <NUM> to <NUM>/m<NUM> and a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM> and preferably of <NUM> to <NUM>/<NUM>.

The high density polyethylene (HDPE) is characterized by having.

The high density polyethylene (HDPE) preferably has a density (ISO <NUM>) in the range of <NUM> to <NUM>/m<NUM> and more preferably of <NUM> to <NUM>/m<NUM>, like <NUM> to <NUM>/m<NUM>.

The MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of the HDPE is preferably in the range of <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>.

The HDPE furthermore preferably has a (melt) flow rate ratio FRR<NUM>/<NUM> (MFR<NUM>/MFR<NUM>) of from <NUM> to <NUM> and most preferably from <NUM> to <NUM>.

The HDPE can be unimodal, bimodal or trimodal.

In one embodiment, the high density polyethylene (HDPE) consists of <NUM> polyethylene components (C) and (D), thus being a bimodal HDPE, whereby the bimodal HDPE is produced in a <NUM> stage-polymerization process.

In another embodiment, the polyethylene component (C) consists of ethylene polymer fractions (C-<NUM>) and (C-<NUM>), thus, the multimodal HDPE is a trimodal HDPE, whereby the trimodal HDPE is produced in a <NUM>-stage polymerization step.

In a preferred embodiment, i.e. embodiment (I), the multimodal HDPE is a trimodal HDPE, which is produced in the presence of a metallocene catalyst system or a Ziegler-Natta catalyst system, preferably in the presence of a metallocene catalyst system as described above.

In embodiment (I), the polyethylene component (C) of the trimodal HDPE is an ethylene copolymer and component (D) is an ethylene homopolymer or copolymer.

Preferably, component (D) consists of a single ethylene homopolymer or copolymer. Component (C) is an ethylene copolymer mixture comprising (e.g. consisting of) a first ethylene copolymer fraction (C-<NUM>) and a second ethylene copolymer fraction (C-<NUM>), whereby the comonomer(s) in the first and second ethylene copolymer fractions are the same.

In this embodiment (I) of the present invention, the polyethylene component (C) preferably has a MFR<NUM> in the range of <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>, even more preferably <NUM> to <NUM>/<NUM> and most preferably <NUM> to <NUM>/<NUM>.

The density of the polyethylene component (C) preferably is in the range of <NUM> to <NUM>/m<NUM>, more preferably <NUM> to <NUM>/m<NUM> and even more preferably <NUM> to <NUM>/m<NUM>.

As stated above, in embodiment (I) the polyethylene component (C) is an ethylene copolymer. Preferred ethylene copolymers employ alpha-olefins (e.g. C3-<NUM> alpha-olefins) as comonomers. Examples of suitable alpha-olefins include <NUM>-butene, <NUM>-hexene and <NUM>-octene; <NUM>-butene is an especially preferred comonomer.

Polyethylene component (C) consists of two fractions, i.e. a first ethylene copolymer fraction (C-<NUM>) and a second ethylene copolymer fraction (C-<NUM>).

It is possible that fraction (C-<NUM>) is produced first and then fraction (C-<NUM>) is produced in the presence of fraction (C-<NUM>) in a subsequent reactor or vice versa, i.e. fraction (C-<NUM>) is produced first and then fraction (C-<NUM>) is produced in the presence of fraction (C-<NUM>) in a subsequent reactor. Preferably, fraction (C-<NUM>) is produced first.

The MFR<NUM> and/or the density of fractions (C-<NUM>) and (C-<NUM>) may be the same or may be different from each other.

Thus, the ethylene polymer fraction (C-<NUM>) and/or ethylene polymer fraction (C-<NUM>) preferably has a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>, preferably of <NUM> to <NUM>/<NUM>, more preferably of <NUM> to <NUM>/<NUM> and even more preferably of <NUM> to <NUM>/<NUM>.

Preferably, the MFR<NUM> of fraction (C-<NUM>) is higher than the MFR<NUM> of fraction (C-<NUM>).

The density of the ethylene polymer fraction (C-<NUM>) and/or (C-<NUM>) preferably is in the range of <NUM> to <NUM>/m<NUM>, more preferably <NUM> to <NUM>/m<NUM> and even more preferably <NUM> to <NUM>/m<NUM>.

Preferably, the density of fraction (C-<NUM>) is higher than the density of fraction (C-<NUM>).

The polyethylene component (D) preferably has a MFR<NUM> in the range of <NUM> to <NUM>/<NUM>, more preferably <NUM> to <NUM>/<NUM>, and even more preferably <NUM> to <NUM>/<NUM>.

The density of the polyethylene component (D) preferably is in the range of <NUM> to <NUM>/m<NUM>, more preferably <NUM> to <NUM>/m<NUM> and even more preferably <NUM> to <NUM>/m<NUM>.

As stated above polyethylene component (D) is an ethylene homopolymer or a copolymer.

In case that polyethylene component (D) is an ethylene copolymer, preferred ethylene copolymers employ alpha-olefins (e.g. C3-<NUM> alpha-olefins) as comonomers. Examples of suitable alpha-olefins include <NUM>-butene, <NUM>-hexene and <NUM>-octene; <NUM>-hexene is an especially preferred comonomer.

The multimodal HDPE of embodiment (I) is produced by polymerization using conditions which create a multimodal (i.e. trimodal) polymer product.

Regarding the polymerization process in a three-stage polymerization process, it is referred to the description related to MMCP.

In embodiment (II), the multimodal HDPE is a bimodal HDPE, which is produced in the presence of a metallocene catalyst system or a Ziegler-Natta catalyst system (znHDPE), preferably in the presence of a Ziegler-Natta catalyst system.

The HDPE of embodiment (II) is an ethylene homopolymer or an ethylene copolymer. An ethylene copolymer is a polymer which comprises ethylene monomer and one or more comonomer(s).

The comonomer can be an alpha-olefin having <NUM> to <NUM> carbon atoms, e.g. <NUM>-butene, <NUM>-methyl-<NUM>-pentene, <NUM>-hexene, <NUM>-octene, <NUM>-decene.

More preferably, the HDPE of embodiment (II) is a copolymer of ethylene and <NUM>-butene, <NUM>-hexene or <NUM>-octene, most preferably <NUM>-butene.

Preferably, the total amount of comonomer(s) present in the HDPE is of <NUM> to <NUM> mol%, more preferably of <NUM> to <NUM> mol% and most preferably <NUM> to <NUM> mol%.

The HDPE comprises, or consists of, a lower molecular weight (LMW) component (C) and a higher molecular weight (HMW) component (D); wherein the LMW component (C) is an ethylene homopolymer having a density of from <NUM> to <NUM>/m<NUM> and the HMW component (D) is an ethylene copolymer of ethylene with at least one C4 to C12 alpha-olefin, having a density of from <NUM> to <NUM>/m<NUM>.

The lower molecular weight (LMW) component (C) has a lower molecular weight than the higher molecular weight component (D) and thus higher MFR<NUM> than the higher molecular weight (HMW) component (D).

The HDPE used according to the present invention is preferably produced in the presence of a Ziegler-Natta catalyst system and is thus a znHDPE.

As the bimodal znHDPE, resin Borstar® FB5600 as produced by Borouge may be used.

The core layer (CL) preferably comprises <NUM> to <NUM> wt%, more preferably <NUM> to <NUM> wt% and still more preferably <NUM> to <NUM> wt% based on the total weight of the core layer (CL) of a metallocene-catalysed multimodal polyethylene copolymer (MMCP) as described for the sealing layer (SL); and <NUM> to <NUM> wt%, more preferably <NUM> to <NUM> wt% and still more preferably <NUM> to <NUM> wt% based on the total weight of the core layer (CL) of a Ziegler-Natta catalysed linear low density polyethylene being preferably a multimodal alpha-olefin terpolymer, preferably having a density (ISO <NUM>) in the range of <NUM> to <NUM>/m<NUM> and a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>.

As metallocene-catalysed multimodal polyethylene copolymer (MMCP) the same or a different MMCP as described for the sealing layer (SL) can be used.

The Ziegler-Natta catalysed linear low density polyethylene (znLLDPE) has a density (ISO <NUM>) in the range of <NUM> to <NUM>/m<NUM>, preferably of <NUM> to <NUM>/m<NUM>, more preferably of <NUM> to <NUM>/m<NUM>, like <NUM> to <NUM>/m<NUM>.

The MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) of the znLLDPE is in the range of <NUM> to <NUM>/<NUM>, preferably of <NUM> to <NUM>/<NUM>, more preferably of <NUM> to <NUM>/<NUM>, like <NUM> to <NUM>/<NUM>.

The znLLDPE contains at least one or two comonomer(s). Suitable comonomers are C3-C10 alpha-olefin comonomers.

Thus, the znLLDPE can be a copolymer of ethylene and one C3-C10 alpha-olefin comonomer or a terpolymer of ethylene and two different C3-C10 alpha-olefin comonomers.

Preferably, the comonomers are selected from the group of <NUM>-butene, <NUM>-hexene and <NUM>-octene. It is preferred if the comonomer employed is <NUM>-butene and/or <NUM>-hexene.

More preferred are terpolymers comprising <NUM>-butene and <NUM>-hexene comonomers.

The total comonomer content of the znLLDPE is preferably in the range of <NUM> to <NUM> mol%, more preferably of <NUM> to <NUM> mol% and even more preferably of <NUM> to <NUM> mol%. <NUM>-butene is preferably present in an amount of <NUM> to <NUM> mol%, more preferably of <NUM> to <NUM> mol%, and even more preferably of <NUM> to <NUM> mol% and <NUM>-hexene is present in an amount of <NUM> to <NUM> mol%, more preferably of <NUM> to <NUM> mol% and even more preferably of <NUM> to <NUM> mol%.

In one embodiment of the multilayered film according to the invention, the znLLDPE for the core layer (CL), comprises.

The LMW homopolymer fraction (X-<NUM>) has a lower molecular weight than the HMW terpolymer fraction (X-<NUM>).

In a further embodiment of the present invention the lower molecular weight (LMW) homopolymer of ethylene (X-<NUM>) consists of one or two fractions, i.e. of one or two homopolymers of ethylene.

In case that the lower molecular weight (LMW) homopolymer of ethylene (X-<NUM>) consists of two homopolymers of ethylene, these two fractions are named (LMW-<NUM>) and (LMW-<NUM>).

The lower molecular weight homopolymer (X-<NUM>) of the znLLDPE has a melt index MFR<NUM> according to ISO <NUM> (<NUM>) in the range of from <NUM> to <NUM>/<NUM>, preferably of from <NUM> to <NUM>/<NUM>; a density according to ISO <NUM> in the range of from <NUM> to <NUM>/m<NUM>, preferably <NUM> to <NUM>/m<NUM> and a comonomer content in the range of from <NUM> to <NUM> mol%, preferably from <NUM> to <NUM> mol%.

The amount of the lower molecular weight fraction (X-<NUM>) of the znLLDPE is in the range of <NUM> to <NUM> wt%, preferably <NUM> to <NUM> wt% and more preferably <NUM> to <NUM> wt%.

The expression "homopolymer of ethylene" used herein refers to a polyethylene that consists substantially, i.e. to at least <NUM> wt%, preferably at least <NUM> wt% and more preferably at least <NUM> wt% by weight, like at least <NUM> wt% of ethylene.

In case that the lower molecular weight (LMW) homopolymer of ethylene (X1) consists of two homopolymers of ethylene, i.e. fractions (LMW-<NUM>) and (LMW-<NUM>), these two fractions preferably have a different MFR2 according to ISO <NUM> (<NUM>).

The homopolymer fraction (LMW-<NUM>) preferably has a MFR2 according to ISO <NUM> (<NUM>) in the range of <NUM> to <NUM>/<NUM>, more preferably in the range of <NUM> to <NUM>/<NUM>, whereas the homopolymer fraction (LMW-<NUM>) preferably has a MFR2 according to ISO <NUM> (<NUM>) in the range of <NUM> to <NUM>/<NUM>, more preferably in the range of <NUM> to <NUM>/<NUM>.

The MFR2 of fraction (LMW-<NUM>) is preferably lower than the MFR2 of the total lower molecular weight (LMW) homopolymer of ethylene (X-<NUM>).

According to a preferred embodiment the ratio of MFR<NUM>(LMW-<NUM>)/MFR<NUM>(X-<NUM>) may be for example between greater than <NUM> and up to <NUM>, preferably between <NUM> and <NUM>, such as <NUM> to <NUM>. Ideally, the MFR difference between the first and second homopolymer fraction (LMW-<NUM>) and (LMW-<NUM>) is as high as possible.

Ideally, the MFR difference between the first homopolymer fraction (LMW-<NUM>) and the MFR<NUM> of the total lower molecular weight (LMW) homopolymer of ethylene (X-<NUM>) is as high as possible e.g. MFR<NUM> of first homopolymer fraction (LMW-<NUM>) may be at least <NUM>/<NUM>, such as at least <NUM>/<NUM> or such as <NUM> to <NUM>/<NUM> lower than the MFR<NUM> of the total lower molecular weight (LMW) homopolymer of ethylene (X-<NUM>).

The density of the two homopolymer fractions (LMW-<NUM>) and (LMW-<NUM>) may be the same or may be different and is in the range of <NUM> to <NUM>/m<NUM>, preferably <NUM> to <NUM>/m<NUM> or <NUM> to <NUM>/m<NUM>.

In an embodiment of the present invention the density of homopolymer fractions (LMW-<NUM>) and (LMW-<NUM>) are the same or differ +/- <NUM>/m<NUM>, preferably +/- <NUM>/m<NUM>.

The total lower molecular weight (LMW) homopolymer of ethylene (X-<NUM>) may comprise <NUM> to <NUM> wt% of the first ethylene homopolymer fraction (LMW-<NUM>) and <NUM> to <NUM> wt% of the second ethylene homopolymer fraction (LMW-<NUM>). In some embodiments, there is an excess of the second ethylene homopolymer fraction (LMW-<NUM>), e.g. <NUM> to <NUM> wt% of the second ethylene homopolymer fraction (LMW-<NUM>).

In another embodiment the total lower molecular weight (LMW) homopolymer of ethylene (X-<NUM>) contains the same amount of first and second ethylene homopolymer fractions (LMW-<NUM>) and (LMW-<NUM>).

The higher molecular weight fraction (X-<NUM>) has a lower MFR<NUM> and a lower density than the lower molecular weight fraction (X-<NUM>).

Preferably, the znLLDPE is produced in a multi-stage, e.g. two-stage or three-stage polymerization using the same Ziegler-Natta catalyst in all stages. Preferably, the znLLDPE is made using a slurry polymerization in at least one loop reactor followed by a gas phase polymerization in a gas phase reactor.

A loop reactor - gas phase reactor system or loop - loop - gas phase reactor system is well known as Borealis technology, i.e. a BORSTAR® reactor system.

In one embodiment, the znLLDPE is thus preferably formed in a two-stage process comprising a first slurry loop polymerization followed by gas phase polymerization in the presence of a Ziegler-Natta catalyst.

Preferably, the lower molecular weight fraction (X-<NUM>) is produced in a continuously operating loop reactor where ethylene is polymerized in the presence of a Ziegler-Natta catalyst and the higher molecular weight fraction (X-<NUM>) is then formed in a gas phase reactor using the same Ziegler-Natta catalyst.

Such znLLDPEs are known in the state of the art and are described e.g. in <CIT> or <CIT> or are commercially available, such as BorShape™ FX1001 and BorShape™ FX1002 (both from Borealis AG).

The multilayered film according to the present invention has an attractive balance of mechanical, e.g. tensile modulus (TM), and sealing properties, e.g. SIT and/or hot tack force (HTF).

Thus, the films of the invention have a sealing initiation temperature (SIT) determined as described in the experimental part on a <NUM>-layered blown film with a thickness of <NUM> of below <NUM>, preferably in the range of <NUM> to <NUM>, more preferably in the range of <NUM> to <NUM>, and even more preferably in the range of <NUM> to <NUM>.

The films of the invention are further characterized by a hot tack force (maximum Hot tack force) of at least <NUM> N, when measured according to ASTM F <NUM> - <NUM> (<NUM>), method B on a three-layered blown film sample (<NUM> thickness).

Preferably, the hot tack force (HTF) is in the range of <NUM> N up to <NUM> N, more preferably in the range of <NUM> to <NUM> N and even more preferably in the range of <NUM> to <NUM> N.

Another preferred embodiment in accordance with the present invention stipulates that the multilayered film has a Tensile Modulus in MD (ISO <NUM>-<NUM>) in the range of <NUM> to <NUM> MPa, preferably in the range of <NUM> to <NUM> MPa and more preferably in the range of <NUM> to <NUM> MPa; and/or a Tensile Modulus in TD (ISO <NUM>-<NUM>) in the range of <NUM> to <NUM> MPa, preferably in the range of <NUM> to <NUM> MPa and more preferably in the range of <NUM> to <NUM>; and/or a Dart Drop Strength (ISO <NUM>-<NUM>) in the range of <NUM> to <NUM>, preferably in the range of <NUM> to <NUM>, and more preferably in the range of <NUM> to <NUM>.

Both properties measured on a three-layered blown film sample (<NUM> thickness).

In another embodiment, the films show improved sealing performance (lower SIT) (without deteriorating the mechanical performance (stiffness and dart-drop impact strength (DDI)), which is expressed by the relation between mechanical properties and sealing properties according to formula (II): <MAT> determined on <NUM> test blown film, wherein the Tensile Modulus (TM) in machine direction is measured according to ISO <NUM>-<NUM> at <NUM> on <NUM> test blown films, DDI is the dart-drop impact strength determined according to ISO <NUM>-<NUM> on a <NUM> test blown film and SIT is the sealing initiation temperature measured as described in the experimental part on a <NUM> test blown film.

Preferably TM(MD)*DDI/SIT for this embodiment is > <NUM>, and more preferably > <NUM>.

A suitable upper limit for TM(MD)*DDI/SIT for this embodiment is <NUM>, preferably <NUM>, and more preferably <NUM>.

Additionally the optical properties are not destroyed and kept on an acceptable level.

Thus, multilayered films according to the present invention may have a haze measured according to ASTM D1003 on a <NUM> <NUM>-layered test blown film of below <NUM>%, preferably in the range of <NUM> to <NUM>%, more preferably <NUM> to <NUM>% and even more preferably <NUM> to below <NUM>%.

Another aspect of the present invention relates to a method for producing the multilayered article.

The multilayered film according to the present invention is generally prepared by a conventional process, wherein the layers of the film are co-extruded.

The different polymer components in any of the layers of the film are typically intimately mixed prior to layer formation, for example using a twin screw extruder, preferably a counter-rotating extruder or a co-rotating extruder. Then, the blends are converted into a coextruded film.

Generally, the multilayered film according to the present invention can be produced by a blown film or cast film process, preferably by a blown film process.

In order to manufacture such films, for example at least three polymer melt streams are simultaneously extruded (i.e. coextruded) through a multi-channel tubular, annular or circular die to form a tube which is blown-up, inflated and/or cooled with air (or a combination of gases) to form a film. The manufacture of blown film is a well-known process.

The blown (co-)extrusion can be effected at a temperature in the range <NUM> to <NUM>, more preferably <NUM> to <NUM> and cooled by blowing gas (generally air) at a temperature of <NUM> to <NUM>, more preferably <NUM> to <NUM> to provide a frost line height of <NUM> to <NUM> times, more preferably <NUM> to <NUM> times the diameter of the die.

The blow up ratio (BUR) should generally be in the range of <NUM> to <NUM>, preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>.

A further aspect of the present invention refers to the use of the multilayered film as packaging material, preferably for food and/or medical products.

The melt flow rate (MFR) of the MMCP was determined according to ISO <NUM> - Determination of the melt mass-flow rate (MFR) and melt volume-flow rate (MVR) of thermoplastics -- Part <NUM>: Standard method and is indicated in g/<NUM>. The MFR is an indication of the flowability, and hence the processability, of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer. The MFR of polyethylene is determined at a temperature of <NUM> and may be determined at different loadings such as <NUM> (MFR<NUM>), <NUM> (MFR<NUM>) or <NUM> (MFR<NUM>).

The density was measured according to ISO <NUM> and ISO1872-<NUM> for sample preparation.

Data may be measured with a TA Instrument Q2000 differential scanning calorimetry (DSC) on <NUM> to <NUM> samples. DSC was run according to ISO <NUM> / part <NUM> /method C2 in a heat / cool / heat cycle with a scan rate of <NUM>/min in the temperature range of -<NUM> to +<NUM>. Crystallization temperature (Tc) and crystallization enthalpy (Hc) were determined from the cooling step, while melting temperature (Tm) and melting enthalpy (Hm) are determined from the second heating step.

The glass transition temperature Tg was determined by dynamic mechanical analysis according to ISO <NUM>-<NUM>. The measurements were done in torsion mode on compression moulded samples (40x10x1 mm3) between -<NUM> and +<NUM> with a heating rate of <NUM>/min and a frequency of <NUM>.

Sealing initiation temperature (SIT); sealing end temperature (SET), sealing range:
The method determines the sealing temperature range (sealing range) of polyethylene films, in particular blown films or cast films. The sealing temperature range is the temperature range, in which the films can be sealed according to conditions given below.

The lower limit (heat sealing initiation temperature (SIT)) is the sealing temperature at which a sealing strength of <NUM> N is achieved. The upper limit (sealing end temperature (SET)) is reached, when the films stick to the sealing device.

The measurement was done according to the slightly modified ASTM F1921 - <NUM>, where the test parameters sealing pressure, cooling time and test speed have been modified. The determination of the force/temperature curve was continued until thermal failure of the film. The sealing range was determined on a J&B Universal Sealing Machine Type <NUM> with a <NUM> layer test blown film of <NUM> thickness with the following further parameters:.

Hot Tack temperature (lowest temperature to get maximum Hot tack force) and Hot tack (maximum Hot tack force) were measured according to ASTM F <NUM> method B on a three-layer blown film of <NUM> thickness with below settings:.

Q-name instrument: Hot Tack - Sealing Tester
Model: J&B model <NUM> MB.

Seal Pressure: <NUM> N/mm<NUM>
Seal Time: <NUM>
Coating of sealing bars:NIPTEF ®
Roughness of coating sealing bars: <NUM> [µm]
Film Specimen width: <NUM>
Cool time: <NUM>
Peel Speed: <NUM>/s
Start temperature: <NUM>
End temperature: burn through and/or shrinking
Increments: <NUM>.

All film test specimens were prepared in standard atmospheres for conditioning and testing at <NUM> (± <NUM>) and <NUM> % (± <NUM> %) relative humidity. The minimum conditioning time of test specimen in standard atmosphere just before start testing is at least <NUM>. The minimum storage time between extrusion of film sample and start testing is at least <NUM>. The hot-tack measurement determines the strength of heat seals formed in the films, immediately after the seal has been made and before it cools to ambient temperature.

The hot-tack force was measured as a function of temperature within the temperature range and with temperature increments as indicated above. The number of test specimens were at least <NUM> specimens per temperature. The Hot-tack force is evaluated as the highest force (maximum peak value) with failure mode "peel".

The DDI was measured according to ISO <NUM>-<NUM>:<NUM> / Method A from the films (non-oriented films and laminates) as produced indicated below. This test method covers the determination of the energy that causes films to fail under specified conditions of impact of a free-falling dart from a specified height that would result in failure of <NUM> % of the specimens tested (Staircase method A). A uniform missile mass increment is employed during the test and the missile weight is decreased or increased by the uniform increment after test of each specimen, depending upon the result (failure or no failure) observed for the specimen.

Haze was determined according to ASTM D <NUM>-<NUM> on <NUM> layered films with <NUM> thickness as produced indicated below.

Tensile modulus (MPa) was measured in machine (MD) and transverse direction (TD) according to ISO <NUM>-<NUM> on film samples prepared as described below with a film thickness of <NUM> and at a cross head speed of <NUM>/min.

Quantitative <NUM>C{<NUM>H} NMR spectra recorded in the molten-state using a Bruker Advance III <NUM> NMR spectrometer operating at <NUM> and <NUM> for <NUM> and 13C respectively. All spectra were recorded using a <NUM>C optimised <NUM> magic-angle spinning (MAS) probe head at <NUM> using nitrogen gas for all pneumatics. Approximately <NUM> of material was packed into a <NUM> outer diameter zirconia MAS rotor and spun at <NUM>. This setup was chosen primarily for the high sensitivity needed for rapid identification and accurate quantification {<NUM>, <NUM>, <NUM>} Standard single-pulse excitation was employed utilising the NOE at short recycle delays {<NUM>, <NUM>} and the RS-HEPT decoupling scheme {<NUM>, <NUM>}. A total of <NUM> (<NUM>) transients were acquired per spectra.

Quantitative <NUM>C{<NUM>H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts are internally referenced to the methyl isotactic pentad (mmmm) at <NUM> ppm.

Characteristic signals corresponding to regio defects were not observed {<NUM>}. The amount of propene was quantified based on the main Sαα methylene sites at <NUM> ppm: <MAT>.

Characteristic signals corresponding to the incorporation of <NUM>-butene were observed and the comonomer content quantified in the following way. The amount isolated <NUM>-butene incorporated in PPBPP sequences was quantified using the integral of the αB2 sites at <NUM> ppm accounting for the number of reporting sites per comonomer: <MAT>.

The amount consecutively incorporated <NUM>-butene in PPBBPP sequences was quantified using the integral of the ααB2 site at <NUM> ppm accounting for the number of reporting sites per comonomer: <MAT>.

The total <NUM>-butene content was calculated based on the sum of isolated and consecutively incorporated <NUM>-butene: <MAT>.

The total mole fraction of <NUM>-butene in the polymer was then calculated as: fB = (Btotal / (Etotal + Ptotal + Btotal)).

Characteristic signals corresponding to the incorporation of ethylene were observed and the comonomer content quantified in the following way. The amount isolated ethylene incorporated in PPEPP sequences was quantified using the integral of the Sαγ sites at <NUM> ppm accounting for the number of reporting sites per comonomer: <MAT>.

With no sites indicative of consecutive incorporation observed the total ethylene comonomer content was calculated solely on this quantity: <MAT>.

The total mole fraction of ethylene in the polymer was then calculated as: <MAT>.

The mole percent comonomer incorporation was calculated from the mole fractions: <MAT> <MAT>.

The weight percent comonomer incorporation was calculated from the mole fractions: <MAT> <MAT>.

Xylene cold solubles (XCS) content for Notio was measured at <NUM> according to ISO <NUM>, first edition; <NUM>-<NUM>-<NUM>.

TAFMER™ PN-<NUM> is a propylene/ethylene/<NUM>-butene terpolymer elastomer, commercially available from Mitsui. Density (ASTM D1505) of <NUM>/m<NUM>, MFR<NUM> (<NUM>, <NUM>; (ASTM D1238), of <NUM>/<NUM>, melting point Tm (DSC ISO <NUM>) <NUM>, Tg -<NUM>, XCS <NUM> wt%, C2 content <NUM> wt%, C4 content <NUM> wt%.

FX1001 is a multimodal alpha-olefin terpolymer (MFR<NUM> (<NUM>/<NUM>), ISO <NUM>): <NUM>/<NUM>, density (ISO <NUM>): <NUM>/m<NUM>, Tm <NUM>, produced with a Ziegler-Natta catalyst) commercially available as BorShape™ FX1001 from Borealis AG and contains antioxidant.

Queo™ 7001LA is an unimodal ethylene based <NUM>-octene plastomer MFR<NUM> (<NUM>/<NUM>; ISO <NUM>): <NUM>/<NUM>, density (ISO <NUM>): <NUM>/m<NUM>, Tm <NUM>, produced in a solution polymerization process using a metallocene catalyst, commercially available from Borealis AG and contains processing stabilizers.

HDPE Borstar® FB5600 commercially available from Borouge, is a bimodal ethylene copolymer, density (ISO <NUM>) <NUM>/m<NUM>, Tm <NUM>, MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) <NUM>/<NUM>, MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) <NUM>/<NUM>, MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) <NUM>/<NUM>. MFR<NUM>/MFR<NUM> <NUM>.

Kraton™ G1645 is a linear triblock copolymer based on styrene and ethylene/butylene, commercial available from Kraton Corporation.

MMCP is a multimodal copolymer and was prepared as follows.

<NUM> of silica (PQ Corporation ES757, calcined <NUM>) was added from a feeding drum and inertized in a reactor until O<NUM> level below <NUM> ppm was reached.

-% MAO in toluene (<NUM>) was added into another reactor from a balance followed by toluene (<NUM>) at <NUM> (oil circulation temp) and stirring <NUM> rpm. Stirring speed was increased <NUM> rpm -> <NUM> rpm after toluene addition, stirring time <NUM> minutes. Metallocene Rac-dimethylsilanediylbis{<NUM>-(<NUM>-(trimethylsilyl)furan-<NUM>-yl)-<NUM>,<NUM>-dimethylcyclopentadien-<NUM>-yl}zirconium dichloride <NUM> was added from a metal cylinder followed by flushing with <NUM> toluene (total toluene amount <NUM>). Reactor stirring speed was changed to <NUM> rpm for MC feeding and returned back to <NUM> rpm for <NUM> reaction time. After reaction time MAO/tol/MC solution was transferred into a feeding vessel.

Reactor temperature was set to <NUM> (oil circulation temp) and stirring was turned to <NUM> rpm during MAO/tol/MC addition. MAO/tol/MC solution (<NUM>) was added within <NUM> minutes followed by <NUM> minutes stirring time (oil circulation temp was set to <NUM>). After stirring "dry mixture" was stabilised for <NUM> hours at <NUM> (oil circulation temp), stirring <NUM> rpm. Reactor was turned <NUM>° (back and forth) and stirring was turned on <NUM> rpm for few rounds once an hour. After stabilisation the catalyst was dried at <NUM> (oil circulation temp) for <NUM> hours under nitrogen flow <NUM>/h, followed by <NUM> hours under vacuum (same nitrogen flow with stirring <NUM> rpm). Dried catalyst was sampled and HC content was measured in the glove box with Sartorius Moisture Analyser, (Model MA45) using thermogravimetric method. Target HC level was < <NUM> % (actual <NUM> %).

The polymerization was carried out in a Borstar pilot plant with a <NUM>-reactor set-up (loop <NUM> - loop <NUM> - GPR) and a prepolymerization loop reactor according to the conditions as given in Table <NUM>.

The polymers (MMCP-<NUM> and MMCP-<NUM>) were mixed with <NUM> ppm of Irganox B561 (commercially available from BASF SE) and <NUM> ppm of Dynamar FX <NUM> (commercially available from <NUM>) compounded and extruded under nitrogen atmosphere to pellets by using a JSW extruder so that the SEI was <NUM> kWh/kg and the melt temperature <NUM>.

Table <NUM> summarizes some properties of the MMCPs.

<NUM>-layered films having the composition shown in Table <NUM> with a total thickness of <NUM> were produced on a Collin <NUM> layer lab line (melt temperature: <NUM>, BUR <NUM>:<NUM>, uptake speed: <NUM>/min).

In case a blend has been used for one layer, the blending of the components has been done in a ZSK twin screw extruder, before feeding to the Collin <NUM> layer lab line.

Claim 1:
A multilayered film comprising a skin layer (SKL), a core layer (CL) and a sealing layer (SL);
wherein the sealing layer (SL) comprises
(a) <NUM> to <NUM> wt%, based on the total weight of the sealing layer (SL), of a metallocene-catalysed multimodal polyethylene copolymer (MMCP), which consists of an in-situ blend of
(i) <NUM> to <NUM> wt% based on the total weight of MMCP of an ethylene-<NUM>-butene polymer component (A) and
(ii) <NUM> to <NUM> wt% based on the total weight of MMCP of an ethylene-<NUM>-hexene polymer component (B); wherein
the ethylene-<NUM>-butene polymer component (A) has
• a density (ISO <NUM>) in the range of <NUM> to <NUM>/m<NUM>;
• a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>; and
the ethylene-<NUM>-hexene polymer component (B) has
• a density (ISO <NUM>) in the range of <NUM> to <NUM>/m<NUM>;
• a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>; and
the metallocene-catalysed multimodal polyethylene copolymer (MMCP) has
• a density (ISO <NUM>) in the range of <NUM> to <NUM>/m<NUM>;
• a MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) in the range of <NUM> to <NUM>/<NUM>; and
• a ratio of the MFR<NUM> (<NUM>, <NUM>, ISO <NUM>) to MFR<NUM> (<NUM>, <NUM>, ISO <NUM>), MFR<NUM>/MFR<NUM>, in the range of <NUM> to <NUM>; and
(b) <NUM> to <NUM> wt%, based on the total weight of the sealing layer (SL), of an elastomer being a terpolymer of propylene, ethylene and <NUM>-butene having
• a density (ASTM D1505) in the range of <NUM> to <NUM>/m<NUM>;
• a MFR<NUM> (<NUM>, <NUM>, ASTM D1238) in the range of <NUM> to <NUM>/<NUM>;
• a melting point (measured by DSC according to ISO <NUM>) in the range of <NUM> to <NUM>;
• a xylene cold soluble (XCS) content, determined according to ISO <NUM> at a temperature of <NUM>, in the range of <NUM> to <NUM> wt%, based on the total weight of the elastomer;
• a <NUM>-butene content, measured by <NUM>C{<NUM>H} NMR as described in the experimental part in the range of <NUM> to <NUM> wt%, based on the total weight of the elastomer and an ethylene content, measured by <NUM>C{<NUM>H} NMR as described in the experimental part in the range of <NUM> to <NUM> wt%, based on the total weight of the elastomer; and
wherein the weight proportions of components (a) and (b) add up to <NUM> wt%; and
wherein the sealing layer forms <NUM> to <NUM>% of the total thickness of the multilayered film.