Polyethylene copolymer for a film layer

Abstract

The present invention relates to a metallocene catalysed multimodal polyethylene copolymer (P), the use of the multimodal copolymer of ethylene (P) in film applications and a film comprising the polymer composition of the invention.

Description

TECHNICAL FIELD

[0001] The present invention relates to a metallocene catalysed multimodal polyethylene copolymer (P), the use of the multimodal polyethylene copolymer (P) in film applications and a film comprising the polymer composition of the invention. BACKGROUND

[0002] Due to its excellent cost performance, the most advanced mLLDPE (metallocene catalysed linear low density polyethylene) is widely used in daily life, for example in packaging. One significant drawback is the narrow molecular weight distribution, thus the low shear thinning, which leads to problems in film conversion, for example limiting the production volume.

[0003] Furthermore, the higher production volume of the plastic processing industry is further limited by melt flow instability, which changes the appearance and performance of the final product and creates economic and environmental impact. One important parameter here is the critical shear rate [s -1 ](CSR), at which the melt flow starts to be unstable.

[0004] The processing instability is influenced by the polymer molecular structure and the presence of special additives.

[0005] Ideally, the critical shear rate (CSR) is as high as possible to improve the processing of the polymer melt.

[0006] One common solution to improve the processability of the polymer melt is the addition of so-called process aids. Unfortunately, most suitable process aids are fluorine based polymers, which are a concern in terms of human and environmental health due to their fluorine content.

[0007] As mentioned above, the processability is also influenced by the molecular structure. Multimodal PE polymers with two or more different polymer components are known to process better, but for example, the melt homogenization of the multimodal PE can be problematic, leading to a non-uniform final product, for example a high gel content of the final product is manifested.

[0008] Multimodal PE polymers are known in the art.

[0009] WO 2021009189, WO 2021009190 and WO 2021009191 of Borealis disclose a process for producing a multimodal PE polymer in two loop reactors and one gas phase reactor in the presence of a silica supported metallocene catalyst based on the metallocene complex bis(1-methyl-3-n-butylcyclopentadienyl)zirconium(IV) dichloride.

[0010] The total density of the polymers produced in the examples was 938 or 939 kg / m 3The MFR2(190°C, 2.16 kg, ISO 1133) of the polymer component produced in the first loop reactor is about 22 or 23 g / 10 min. The MFR2(190°C, 2.16 kg, ISO 1133) of the polymer component after the second loop reactor is not more than 31 g / 10 min.

[0011] There is no mention at all of the properties of the film (such as tensile modulus (TM) and impact strength in instrumented puncture test (IPT)) and processing parameters (such as critical shear rate).

[0012] WO 2021009192 also discloses such a process. The polymer produced in the examples has a higher density, of 951 kg / m 3 The MFR2(190°C, 2.16 kg, ISO 1133) of the polymer component produced in the first loop reactor is 32 g / 10 min. The MFR2(190°C, 2.16 kg, ISO 1133) of the polymer component after the second loop reactor is not more than 22 g / 10 min.

[0013] There is no mention at all of the properties of the film (such as tensile modulus (TM) and impact strength in instrumented puncture test (IPT)) and processing parameters (such as critical shear rate).

[0014] It is desirable to maximize the processability of a multimodal PE polymer having improved melt flow stability, as expressed by a high critical shear rate (CSR). It goes without saying that any operation performed on the polymer properties in order to be able to improve the processability should not compromise the properties of the final film.

[0015] Furthermore, such a multimodal PE polymer should have a very low ratio of the relevant soluble fraction (determined with Cross-Fractionation Chromatography (CFC)) to density, as this soluble fraction is generally problematic in certain packaging fields (e.g. food packaging).

[0016] Furthermore, it is desirable that all these improvements are achieved without the addition of processing aids.

[0017] The inventors have now found that a metallocene-catalyzed multimodal polyethylene copolymer (P) made with a specific metallocene catalyst and having a specific polymer design has improved processability, which can be seen from a higher possible critical shear rate (CSR).

[0018] Furthermore, such a metallocene-catalyzed multimodal polyethylene copolymer (P) has a very low ratio of the relevant soluble fraction (determined with Cross-Fractionation Chromatography (CFC)) to density.

[0019] Furthermore, films made from such metallocene-catalysed multimodal polyethylene copolymer (P) have improved balanced properties, in particular in terms of stiffness (i.e. tensile modulus) and impact properties, for example in instrumented puncture test (IPT). SUMMARY

[0020] Thus, the present invention relates to a metallocene-catalysed multimodal polyethylene copolymer (P) consisting of (i) 35.0 to 50.0 wt% of an ethylene-1-butene polymer component (A), and (ii) 50.0 to 65.0 wt% of an ethylene-1-hexene polymer component (B),

[0021] wherein the ethylene-1-butene polymer component (A) has

[0022] a density in the range of 930 to 960 kg / m 3 ,

[0023] an MFR2 (190°C, 2.16 kg, ISO 1133) in the range of 30.0 to 300.0 g / 10 min, based on the ethylene-1-butene polymer component (A), a 1-butene content in the range of 0.1 to 3.0 mol%; wherein the ethylene-1-butene polymer component (A) consists of an ethylene-1-butene polymer fraction (A-1) and an ethylene-1-butene polymer fraction (A-2);

[0024] the ethylene-1-hexene polymer component (B) has

[0025] a density in the range of 880 to 920 kg / m 3 ,

[0026] an MFR2 (190°C, 2.16 kg, ISO 1133) in the range of 0.001 to 1.0 g / 10 min, based on the ethylene-1-hexene polymer compound (B), a 1-hexene content in the range of 2.5 to 10.0 mol%,

[0027] wherein the multimodal polyethylene copolymer (P) has

[0028] a density in the range of 910 to 945 kg / m 3 ,

[0029] an MFR2 (190°C, 2.16 kg, ISO 1133) in the range of 0.1 to 3.0 g / 10 min,

[0030] the ratio of the molecular weight (Mw) of the low crystalline fraction (LCF) to the molecular weight (Mw) of the high crystalline fraction (HCF) in the range of 2.5 to 10.0 (Mw(Tp(LCF) / Mw(Tp(HCF)), determined as described in the experimental part;

[0031] the ratio of the half-height width Tp(LCF) to the half-height width Tp(HCF) in the range of 0.9 to 5.9, and

[0032] the ratio of the soluble fraction at 35°C to the density of the multimodal polyethylene copolymer (P) (SF@35°C / density) below 0.007, the soluble fraction at 35°C being determined with cross-fractionation chromatography (CFC) as described in the experimental part. P

[0033] In one embodiment of the present application, the ethylene-1 -butene polymer component (A) of the metallocene catalysed multimodal polyethylene copolymer (P) consists of an ethylene polymer fraction (A-1 ) and an ethylene polymer fraction (A-2), wherein the density of fractions (A-1 ) and (A-2) ranges from 925 to 960 kg / m 3 , the MFR2(190°C, 2.16 kg, ISO 1133) ranges from 30 to 300 g / 10 min, wherein the density and / or the MFR2(190°C, 2.16 kg, ISO 1133) of the ethylene polymer fractions (A-1 ) and (A-2) can be the same or different.

[0034] Surprisingly, the multimodal polyethylene copolymer (P) of the present application provides a film with improved mechanical properties, such as high impact strength in instrumented puncture test (IPT), and at the same time a good tensile modulus.

[0035] The present application further relates to a film comprising the multimodal polyethylene copolymer (P) and the use of the film. DETAILED DESCRIPTION

[0036] Definitions

[0037] Where the term "comprising" or "including" is used in the specification, this term is used in the inclusive sense of "comprising" or "including" but not limited to, and is not used in the exclusive or exhaustive sense. For purposes of the present application, the term "consisting of is considered to be a preferred embodiment of the term "comprising" or "including". If a group is defined to comprise at least one embodiment, this is also understood as disclosing a group that preferably consists of only those embodiments.

[0038] Whenever the terms "including" or "having" are used, these terms are meant to be equivalent to "comprising" or "including" as defined above. ​

[0039] When using an indefinite or definite article, such as "a", "an", or "the", in connection with a singular noun, this includes the plural of the noun, unless specifically stated otherwise.

[0040] The metallocene catalysed multimodal polyethylene copolymer is defined in the present invention as a multimodal polyethylene copolymer (P) which is produced in the presence of a metallocene catalyst.

[0041] In the context of the multimodal polyethylene copolymer (P), the term "multimodal" refers herein to a multimodality in terms of the melt flow rate (MFR) of the ethylene polymer components (A) and (B), i.e. the ethylene polymer components (A) and (B) have different MFR values. As described below, the multimodal polyethylene copolymer (P) can further have a multimodality in terms of one or more other properties between the ethylene polymer components (A) and (B).

[0042] The multimodal polyethylene copolymer (P) of the present invention as defined above, below or in the claims is also referred to herein simply as "multimodal PE" or "multimodal copolymer (P)".

[0043] The following preferred embodiments, properties and subgroups of the multimodal PE and its ethylene polymer components (A) and (B) and its ethylene polymer fractions (A-1) and (A-2) and of the films of the present invention, including preferred ranges thereof, are independently generalisable, such that they can be used in any order or combination to further define preferred embodiments of the multimodal PE and articles of the present invention.

[0044] The multimodal PE and its ethylene polymer components (A) and (B) and its ethylene polymer fractions (A-1) and (A-2)

[0045] The metallocene produced multimodal polyethylene copolymer (P) is referred to herein as "multimodal" because the ethylene-1 -butene polymer component (A), including the ethylene polymer fractions (A-1) and (A-2), and the ethylene-1 -hexene polymer component (B) have been produced under different polymerisation conditions, resulting in different melt flow rates (MFR, e.g. MFR2). That is, the multimodal PE is multimodal at least in terms of the MFR2 difference of the ethylene polymer components (A) and (B).

[0046] The metallocene produced multimodal polyethylene copolymer (P) consists of (i) 35.0 to 50.0 wt% of the ethylene-1 -butene polymer component (A), and (ii) 50.0 to 65.0 wt% of the ethylene-1 -hexene polymer component (B).

[0047] The amounts of (A) and (B) add up to 100.0 wt%.

[0048] The ethylene-1 -butene polymer component (A) consists of ethylene polymer fractions (A-1 ) and (A-2).

[0049] The MFR2of the ethylene polymer fractions (A-1 ) and (A-2) can be different from each other or the same.

[0050] The MFR2(190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fractions (A-1 ) and (A-2) is in the range of 30.0 to 300.0 g / 10 min, preferably 35.0 to 250.0 g / 10 min, more preferably 40.0 to 200.0 g / 10 min, even more preferably 45 to 150.0 g / 10 min.

[0051] The MFR2of the ethylene polymer components (A) and (B) is different from each other.

[0052] The MFR2(190 °C, 2.16 kg, ISO 1133) of the ethylene polymer component (A) is in the range of 30.0 to 300 g / 10 min, preferably 35.0 to 250.0 g / 10 min, more preferably 40.0 to 200.0 g / 10 min, even more preferably 45 to 150.0 g / 10 min.

[0053] The MFR2(190 °C, 2.16 kg, ISO 1133) of the ethylene polymer component (B) is in the range of 0.001 to 1.0 g / 10 min, preferably 0.005 to 0.9 g / 10 min, more preferably 0.008 to 0.7 g / 10 min, even more preferably 0.01 to 0.5 g / 10 min.

[0054] The MFR2(190 °C, 2.16 kg, ISO 1133) of the multimodal copolymer (P) is in the range of 0.1 to 3.0 g / 10 min, preferably 0.2 to 2.5 g / 10 min, more preferably 0.3 to 2.0 g / 10 min, even more preferably 0.4 to 1.5.

[0055] Of course, in addition to the multimodality with respect to the MFR2of the ethylene polymer components (A) and (B) (i.e. the difference between them), the multimodal PE of the present application can also be multimodal with respect to, for example, one or both of two other properties:

[0056] The multimodality with respect to the difference between:

[0057] - the comonomer content present in the ethylene polymer components (A) and (B); and / or - the density of the ethylene polymer components (A) and (B).

[0058] Preferably, the multimodal polymer (P) is further multimodal in terms of the comonomer content of the ethylene polymer components (A) and (B).

[0059] The comonomer type of the polymer fractions (A-1) and (A-2) is the same, thus both fractions have 1-butene as comonomer.

[0060] The comonomer content of components (A) and (B) can be measured, or in the preferred case, one of the components is first produced, then the other component is produced in the presence of the first produced component in a so-called multi-stage 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 the following formula:

[0061] Comonomer content in component B (mol%) = (Comonomer content in final product (mol%) - (Weight fraction of component A * Comonomer content in component A (mol%)) / Weight fraction of component B

[0062] The total amount of 1-butene based on the multimodal polymer (P) preferably ranges from 0.1 to 1.0 mol%, preferably from 0.2 to 0.8 mol%, more preferably from 0.3 to 0.7 mol%.

[0063] The total amount of 1-hexene based on the multimodal polymer (P) preferably ranges from 1.5 to 8.0 mol%, preferably from 2.0 to 6.0 mol%, more preferably from 2.2 to 4.0 mol%.

[0064] The total amount of 1-butene present in the ethylene-1-butene polymer component (A) (mol%) based on the ethylene-1-butene polymer component (A) is from 0.1 to 3.0 mol%, preferably from 0.5 to 2.6 mol%, more preferably from 0.8 to 2.0 mol%, more preferably from 1.0 to 1.8 mol%.

[0065] The total amount of 1-hexene present in the ethylene-1-hexene polymer component (B) (mol%) based on the ethylene-1-hexene polymer component (B) is from 2.5 to 10.0 mol%, preferably from 3.0 to 8.0 mol%, more preferably from 3.5 to 6.0 mol%.

[0066] Even more preferably, the multimodal polymer (P) of the present application is further multimodal in terms of the difference in density between the ethylene polymer component (A) and the ethylene polymer component (B). Preferably, the density of the ethylene polymer component (A) is different, preferably higher, than the density of the ethylene polymer component (B).

[0067] The density of the ethylene polymer component (A) ranges from 930 to 960 kg / m3 , preferably 935 to 955 kg / m 3 , more preferably 938 to 950 kg / m 3 and / or the density of the ethylene polymer component (B) ranges from 880 to 920 kg / m 3 , preferably 885 to 915 kg / m 3 , more preferably 890 to 910 kg / m 3 .

[0068] The density of the polymer fractions (A-1) and (A-2) ranges from 925 to 960 kg / m 3 , preferably 928 to 955 kg / m 3 , more preferably 930 to 950 kg / m 3 , most preferably 935 to 945 kg / m 3 .

[0069] The density of the ethylene polymer fractions (A-1) and (A-2) can be the same or different from each other.

[0070] The metallocene catalysed multimodal copolymer (P) is preferably a linear low density polyethylene (LLDPE) which has the well-known meaning.

[0071] The density of the multimodal copolymer (P) ranges from 910 to 945 kg / m 3 , preferably 912.0 to 925 kg / m 3 , more preferably 913.0 to 920.0 kg / m 3 .

[0072] More preferably, the multimodal copolymer (P) is multimodal at least with respect to the MFR2, the comonomer content and the density of the ethylene polymer components (A) and (B), i.e. has differences, as defined above, below or in the claims, including any preferred ranges or embodiments of the polymer composition.

[0073] Further, the multimodal copolymer (P) can have a molecular weight distribution (Mw / Mn) determined with GPC which ranges from low 4.6 to high 7.2, preferably in the range of 5.0 to 7.0, more preferably in the range of 5.5 to 6.8.

[0074] Further, the ratio of the molecular weight (Mw) of the low crystalline fraction (LCF) to the molecular weight (Mw) of the high crystalline fraction (HCF) of the multimodal copolymer (P) (Mw(Tp(LCF) / Mw(Tp(HCF)) determined as described in the experimental part ranges from 2.5 to 10.0, preferably in the range of 3.0 to 8.0, more preferably in the range of 3.5 to 6.5.

[0075] Furthermore, the ratio of the half-height width Tp(LCF) to the half-height width Tp(HCF) of the multimodal copolymer (P) ranges from 0.9 to 5.9, preferably from 0.9 to 4.0, more preferably from 1.0 to 2.0.

[0076] The high crystalline fraction (HCF) and the low crystalline fraction (LCF) are defined as:

[0077] The high crystalline fraction (HCF) refers to the wt% of the polymer fraction having a crystallization temperature higher than 90 °C, mainly containing homopolymer polyethylene chains or chains with very low content of branches.

[0078] The low crystalline fraction (LCF) refers to the wt% of the polymer fraction having a crystallization temperature in the range from 30 °C to lower than 90 °C.

[0079] Furthermore, the ratio of the soluble fraction at 35 °C to the density of the multimodal polyethylene copolymer (P) (SF@35 °C / density) of the multimodal copolymer (P) is lower than 0.007, preferably lower than 0.006, more preferably lower than 0.005, for example ranging from 0.001 to 0.007, preferably from 0.001 to lower than 0.006, more preferably from 0.001 to lower than 0.005, the soluble fraction at 35 °C being determined with Cross Fraction Chromatography (CFC) as described in the experimental part. P

[0080] Within the scope of the present application, the first and second ethylene polymer fractions (A-1 and A-2) of the ethylene polymer component (A) are present in a weight ratio of from 4:1 to 1:4, for example from 3:1 to 1:3, or from 2:1 to 1:2, or 1:1.

[0081] The ethylene polymer component (A) is present in an amount of from 35.0 to 50.0 wt%, preferably in an amount of from 36.0 to 48.0 wt%, even more preferably in an amount of from 38.0 to 45.0 wt%, based on the multimodal polymer (P).

[0082] Therefore, the ethylene polymer component (B) is present in an amount of from 50.0 to 65.0 wt%, preferably in an amount of from 52.0 to 64.0 wt%, more preferably in an amount of from 55.0 to 62.0 wt%, based on the multimodal polymer (P).

[0083] ​The multimodal copolymer (P) can be produced with a three-stage process, which preferably comprises a first slurry reactor (loop reactor 1), wherein this first slurry loop reactor is connected in series to another slurry reactor (loop reactor 2), so that a first ethylene polymer fraction (A-1) produced in loop reactor 1 is fed to loop reactor 2, in which this second ethylene polymer fraction (A-2) is produced in the presence of the first fraction (A-1). Thus, loop reactor 2 is 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 tri-modal polyethylene copolymer. In this case, the reaction conditions in the two slurry reactors are chosen so that products differing in MFR and / or density are produced in the two slurry reactors.

[0084] This process is described, inter alia, in WO 2016 / 198273, WO 2021009189, WO 2021009190, WO 2021009191 and WO 2021009192. The full details of how to make suitable metallocene-catalysed multimodal copolymers (P) can be found in these references.

[0085] A suitable process is the Borstar PE process or the Borstar PE 3G process.

[0086] Thus, the metallocene-catalysed multimodal copolymer (P) according to the present application is preferably produced in a loop-loop-gas phase cascade. Such a polymerisation step can be preceded by a prepolymerisation step. The purpose of the prepolymerisation is to polymerise a small amount of polymer onto the catalyst at low temperature and / or low monomer concentration. By prepolymerisation, the performance of the catalyst in the slurry and / or the properties of the final polymer can be improved. This prepolymerisation step is preferably carried out in the slurry and the amount of polymer produced in the optional prepolymerisation step is counted as the amount (wt%) of the ethylene polymer component (A).

[0087] When a prepolymerisation step is present, the catalyst components are preferably introduced in their entirety into the prepolymerisation step. However, when 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 prepolymerisation stage, while the remainder is introduced into the subsequent polymerisation stage. Furthermore, in this case, it is necessary to introduce so much cocatalyst into the prepolymerisation stage that a sufficient polymerisation reaction is obtained therein.

[0088] It is to be understood that within the scope of the present application, the amount of polymer produced in the prepolymerisation is within 1 to 5 wt% relative to the final metallocene-catalysed multimodal copolymer (P). This can be counted as part of the first ethylene polymer component (A).

[0089] Catalyst

[0090] The metallocene-catalyzed multimodal copolymer (P) used in the process of the present application is prepared using a metallocene catalyst. The metallocene catalyst comprises a metallocene compound and a co-catalyst. The metallocene compound or complex is also referred to herein as an organometallic compound (C).

[0091] The organometallic compound (C) comprises a transition metal (M) of Group 3 to 10 or an actinide or lanthanide element of the Periodic Table (IUPAC 2007).

[0092] According to the present application, the term "organometallic compound (C)" includes any metallocene or non-metallocene compound of a transition metal, which carries at least one organic (coordination) ligand and exhibits catalytic activity alone or together with a co-catalyst. Transition metal compounds are well known in the art and the present application encompasses compounds of metals from Groups 3 to 10, such as Groups 3 to 7, or Groups 3 to 6, such as Groups 4 to 6, of the Periodic Table (IUPAC 2007), as well as lanthanides or actinides.

[0093] In one embodiment, the organometallic compound (C) has the following formula (I):

[0094]

[0095] wherein each X is independently a halogen atom, a C 1-6 -alkyl, C 1-6 -alkoxy, phenyl or benzyl;

[0096] each Het is independently a monocyclic heteroaromatic radical containing at least one heteroatom selected from O or S;

[0097] L is -R'2Si-, wherein each R' is independently a C 1-20 -hydrocarbyl or C 1-10 -alkyl;

[0098] M is Ti, Zr or Hf;

[0099] each R 1 is the same or different C 1-6 -alkyl or C 1-6 -alkoxy;

[0100] each n is 1 to 2;

[0101] each R 2 is the same or different C 1-6 -alkyl, C 1-6 -alkoxy or a -Si(R)3 radical;

[0102] each R is an optionally substituted C1-6 - alkyl-substituted C 1-10 - alkyl or phenyl; and

[0103] each p is 0 to 1.

[0104] Preferably, the compound of formula (I) has the following structure

[0105]

[0106] wherein each X is independently a halogen atom, C 1-6 - alkyl, C 1-6 - alkoxy, phenyl or benzyl;

[0107] L is Me2Si-;

[0108] each R 1 are the same or different and are C 1-6 - alkyl, for example methyl or tert-butyl;

[0109] each n is 1 to 2;

[0110] R 2 is -Si(R)3alkyl; each p is 1 ;

[0111] each R is C 1-6 - alkyl or phenyl.

[0112] A highly preferred complex of formula (I) is

[0113]

[0114]

[0115] Most preferably, the complex dimethylsilanediylbis[2-(5- trimethylsilylfuran-2-yl)-4,5-dimethylcyclopentadien-1-yl]zirconium dichloride is used.

[0116] More preferably, the ethylene polymer components (A) and (B) of the multimodal copolymer (P) are produced using the same metallocene catalyst, i.e. in the presence of the same metallocene catalyst.

[0117] For the formation of the catalyst, a co-catalyst, also known as activator, is used. Co-catalysts comprising Al or B are well known and can be used here. Preferably, an aluminoxane (e.g. MAO) or a boron-based co-catalyst (e.g. borate) is used.

[0118] In contrast to Ziegler Natta catalysis, polyethylene copolymers produced using site catalysis have characteristics that distinguish them from Ziegler Natta materials. In particular, the comonomer distribution is more uniform. This can be shown with TREF or Crystaf techniques. Catalyst residues can also be indicative of the catalyst used. Ziegler Natta catalysts do not contain, for example, Group (IV) metals of Zr or Hf.

[0119] The metallocene-catalyzed multimodal copolymer (P) can contain further polymer components and optionally additives and / or fillers. In case the metallocene-catalyzed multimodal copolymer (P) contains further polymer components, the amount of the further polymer components typically varies between 3.0 and 20.0 wt%, based on the total amount of the metallocene-catalyzed multimodal copolymer (P) and the further polymer components.

[0120] The optional additives and fillers and their amounts are conventional in the field of film applications. Examples of such additives are, inter alia, antioxidants, UV stabilizers, pigments, fillers, antistatic additives, antiblocking agents, nucleating agents, and acid scavengers.

[0121] In one embodiment of the present application, the metallocene-catalyzed multimodal copolymer (P) does not contain any processing aids, in particular does not contain any fluorine-based polymer processing aid.

[0122] It is to be understood here that any additive and / or filler can optionally be added in a so-called masterbatch, which comprises the respective additive and a carrier polymer. In this case, the carrier polymer is not calculated in the polymer components of the metallocene-catalyzed multimodal copolymer (P), but in the amount of the respective additive, based on the total amount of the polymer composition (100 wt%).

[0123] Film of the present application

[0124] The film of the present application comprises at least one layer comprising the metallocene-catalyzed multimodal copolymer (P). The film can be a monolayer film comprising the metallocene-catalyzed multimodal copolymer (P) or a multilayer film wherein at least one layer comprises the metallocene-catalyzed multimodal copolymer (P). The terms “monolayer film” and “multilayer film” have the well-known meaning in the art.

[0125] The layer of the monolayer or multilayer film of the present application can consist of the metallocene-catalyzed multimodal copolymer (P) itself or of a blend of the metallocene-catalyzed multimodal copolymer (P) with other polymers. In case of a blend, any other polymer is different from the metallocene-catalyzed multimodal copolymer (P) and is preferably a polyolefin. Part of the above-mentioned additives can optionally be added to the metallocene-catalyzed multimodal copolymer (P) during the film production process.

[0126] Preferably, at least one layer of the film of the present application comprises at least 50 wt.-%, more preferably at least 60 wt.-%, even more preferably at least 70 wt.-%, still more preferably at least 80 wt.-% of the metallocene catalysed multimodal copolymer (P) of the present application. Most preferably, said at least one layer of the film of the present application consists of the metallocene catalysed multimodal copolymer (P).

[0127] Thus, the film of the present application can comprise a single layer (i.e. monolayer) or can be multilayered. Multilayered films generally and preferably comprise at least 3 layers.

[0128] The film is preferably produced by any conventional film extrusion process known in the art, including cast film and blown film extrusion. Most preferably, the film is a blown or cast film, especially a blown film. For example, blown films are produced by extrusion through an annular die and blown into a tubular film by a bubble which is broken between nip rollers after solidification. The film can then be slit, cut or converted (e.g. folded) as required. Conventional film production techniques can be used in this regard. If the preferred blown or cast film is a multilayer film, the layers are generally co-extruded. The skilled person will be aware of suitable extrusion conditions.

[0129] The film according to the present application can be subjected to post-treatment processes, such as surface modification, lamination or orientation processes, etc. Such orientation processes can be mono-axial (MDO) or biaxial orientation, with mono-axial orientation being preferred.

[0130] In another preferred embodiment, the film is unoriented.

[0131] The resulting film can have any thickness conventional in the art. The thickness of the film is not critical and depends on the end use. Thus, the film can have a thickness of, for example, 300 pm or less, typically from 6 to 200 pm, preferably from 10 to 180 pm, for example from 20 to 150 pm or from 20 to 120 pm. If desired, the polymers of the present application enable thicknesses of less than 100 pm, for example less than 50 pm. Films of the present application can also be produced with thicknesses even less than 20 pm, while maintaining good mechanical properties.

[0132] Furthermore, the present application also relates to the use of the articles of the present application as packaging material, in particular as packaging material for food and / or medical products.

[0133] The film of the present application is characterized by an impact strength in the instrumented puncture test (IPT) determined according to ISO 7765-2 on a 40 pm monolayer test blown film of at least 110 J / mm to 300 J / mm, preferably of 115 J / mm to 250 J / mm, more preferably of 120 J / mm to 200 J / mm.

[0134] Furthermore, the film according to the present application has a good stiffness (tensile modulus measured according to ISO 527-3 on 40 pm single layer test blown film), i.e. (> 160 MPa in both directions).

[0135] Therefore, the film comprising the metallocene catalysed multimodal copolymer (P) has a tensile modulus (measured according to ISO 527-3 on 40 pm single layer test blown film) in machine direction (MD) and transverse direction (TD) ranging from > 160 MPa to 350 MPa, preferably from 180 MPa to 300 MPa.

[0136] The specific design of the metallocene catalysed multimodal copolymer (P) of the present application makes this polymer very advantageous for film making. By using the metallocene catalysed multimodal copolymer (P) of the present application in a film making machine, the benefit of excellent extrudability, in particular a significantly improved processability, can be seen compared to a corresponding film material having the same density and MFR level.

[0137] The improved processability is expressed by the critical shear rate (CSRR) determined according to ISO 11443, which is at least 200 s -1 , preferably at least 500 s -1 , more preferably at least 800 s -1 . A suitable upper limit for the critical shear rate (CSR) is 1500 s -1 , preferably 1300 s -1 .

[0138] The higher possible critical shear rate (CSR) is not at the expense of good mechanical properties.

[0139] The present application will be further described with reference to the following non-limiting examples.

[0140] Determination methods:

[0141] The following methods were used for the determination of the properties of the polymers (including parts and components thereof) and / or any sample preparations thereof as described in the main text or in the experimental part, unless otherwise stated in the specification or experimental part.

[0142] Melt flow rate

[0143] The melt flow rate (MFR) was determined according to ISO 1133, expressed in g / 10 min. The MFR is an indicator of the flow properties of a polymer and thus also of its processability. The higher the melt flow rate, the lower the polymer viscosity. The MFR of polyethylene is determined at 190 °C. The MFR can be determined at different loads, for example 2.16 kg (MFR2), 5 kg (MFR5) or 21.6 kg (MFR 21 ).

[0144] Calculation of MFR2of component B and part (A-2)

[0145] log A = x log B + (1 - x) log C

[0146]

[0147] For component B:

[0148] B = MFR2of component (A)

[0149] C = MFR2of component (B)

[0150] A = final MFR2of the multimodal polyethylene copolymer (P) (blend)

[0151] X = weight fraction of component (A)

[0152] For part (A-2):

[0153] B = MFR2of part (A-1)

[0154] C = MFR2of part (A-2)

[0155] A = final MFR2of the cyclic polymer (= component (A)) (blend)

[0156] X = weight fraction of part (A-1)

[0157] Density

[0158] The density of the polymers was determined according to ASTM D792, method B (equilibrium density at 23 °C) on compression molded test specimens prepared according to EN ISO 1872-2 in kg / m 3 .

[0159] Comonomer content:

[0160] Quantification of the microstructure by NMR spectroscopy

[0161] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content of the polymers.

[0162] Bruker Avance III 500 NMR spectrometer operating at 500.13 and 125.76 MHz for 1 H and 13 C, respectively, quantitative 13 C{ 1 H} NMR spectra were recorded in the molten state. All spectra were recorded using 13C-optimised 7 mm magic angle spinning (MAS) probehead recorded at 150 °C, all pneumatics used nitrogen. Approximately 200 mg of material was packed into a 7 mm outer diameter zirconia MAS rotor and spun at 4 kHz. This set-up was chosen primarily for the high sensitivity required for fast identification and accurate quantification {klimke06, parkinson07, castignolles09}. Standard single-pulse excitation was employed with a 3 s short cycle delay NOE {pollard 04, klimke06} and RS-HEPT decoupling scheme {fillip05, griffin07}. A total of 1024 (1 k) transients were acquired for each spectrum.

[0163] For quantification 13 C{ 1 H}NMR spectra were processed, integrated and the relevant quantitative properties determined from the integrals. All chemical shifts are referenced internally to the bulk methylene signal at 30.00 ppm (δ+).

[0164] The amount of ethylene was quantified using the integration of the methylene (δ+) site at 30.00 ppm and taking into account the number of monomer reporting sites per monomer:

[0165] E = I δ+ / 2

[0166] The presence of isolated comonomer units was corrected based on the number of isolated comonomer units present: Etotai = E + (3*B + 2*H) / 2

[0167] where B and H are defined for their respective comonomers. When both consecutive and non-consecutive comonomer incorporation is present, the correction is made in a similar manner.

[0168] Characteristic signals corresponding to the incorporation of 1 -butene were observed and the comonomer fraction was calculated as the fraction of 1 -butene in the polymer relative to all monomers in the polymer:

[0169] fBtotai = Btotai / (Etotai + Btotai + Htotai)

[0170] The amount of isolated 1 -butene incorporated in EEBEE sequences was quantified using the integration of the *B2 site at 39.8 ppm and taking into account the number of comonomer reporting sites per comonomer:

[0171] B = I *B2

[0172] The amount of consecutive 1 -butene incorporation in EEBBEE sequences was quantified using the integration of the ααB2B2 site at 39.4 ppm and taking into account the number of comonomer reporting sites per comonomer if present:

[0173] BB = 2 * IaB2B2

[0174] The amount of non-consecutively incorporated 1-butene in EEBBEE sequences was quantified using the integration of the ββB2B2site at 24.6 ppm and taking into account the number of comonomer reporting sites per sequence:

[0175] BEB = 2 * IββB2B2

[0176] Since the *B2and *βB2B2sites of isolated (EEBEE) and non-consecutively incorporated (EEBEBEE) 1-butene overlap, respectively, the total amount of isolated 1-butene incorporation was corrected based on the amount of non-consecutively 1-butene present: B = I *B2 - 2 * I ββB2B2

[0177] No BBB sequences were observed. The total 1-butene content was calculated from the sum of isolated, consecutively and non-consecutively incorporated 1-butene:

[0178] Btotal = B + BB + BEB

[0179] The total mole fraction of 1-butene in the polymer was then calculated:

[0180] fB = Btotal / (Etotal + Btotal + Htotal)

[0181] Characteristic signals corresponding to 1-hexene incorporation were observed and the comonomer fraction was calculated as the fraction of 1-hexene in the polymer relative to all monomers in the polymer:

[0182] fHtotal = Htotal / (Etotal + Btotal + Htotal)

[0183] The amount of isolated 1-hexene incorporated in EEHEE sequences was quantified using the integration of the *B4site at 38.3 ppm and taking into account the number of comonomer reporting sites per sequence:

[0184] H = I *B4

[0185] The amount of consecutively incorporated 1-hexene in EEHHEE sequences, if present, was quantified using the integration of the a aB4B4site at 40.5 ppm and taking into account the number of comonomer reporting sites per sequence:

[0186] HH = 2 * Ia aB4B4

[0187] The amount of non-consecutively incorporated 1-hexene in EEHEHEE sequences, if present, was quantified using the integration of the ββB4B4site at 24.7 ppm and taking into account the integration of the number of comonomer reporting sites per sequence: HEH = 2 * IββB4B4

[0188] No HHH sequences were observed. The total content of 1-hexene was calculated from the sum of isolated, continuous and non-continuous incorporated 1-hexene:

[0189] Htotal = H + HH + HEH

[0190] The total mole fraction of 1-hexene in the polymer was then calculated:

[0191] fH = Htotal / (Etotal + Btotal + Htotal)

[0192] The mole percent comonomer incorporation was calculated from the mole fraction:

[0193] B [mol%] = 100 * fB

[0194] H [mol%] = 100 * fH

[0195] The weight percent comonomer incorporation was calculated from the mole fraction:

[0196] B [wt%] = 100 * (fB * 56.11) / ((fB * 56.11) + (fH * 84.16) + ((1 - (fB + fH)) * 28.05))

[0197] H [wt%] = 100 * (fH * 84.16) / ((fB * 56.11) + (fH * 84.16) + ((1 - (fB + fH)) * 28.05))

[0198] References:

[0199] Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H.W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207: 382.

[0200] Parkinson, M., Klimke, K., Spiess, H.W., Wilhelm, M., Macromol. Chem. Phys. 2007; 208: 2128.

[0201] Pollard, M., Klimke, K., Graf, R., Spiess, H.W., Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004; 37: 813.

[0202] Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176, 239

[0203] Griffin, J. M., Tripon, C, Samoson, A., Filip, C, and Brown, S. P., Mag. Res. in Chem. 2007 45, S1, S198

[0204] Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau, M., Polymer 50 (2009) 2373

[0205] Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001 ) 443

[0206] Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A. L., Macromoleucles 30 (1997) 6251

[0207] Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225

[0208] Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128

[0209] Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253

[0210] Molecular weight, molecular weight distribution, Mn, Mw, MWD:

[0211] Molecular weight averages (Mz, Mw, and Mn), molecular weight distribution (MWD) and its breadth described by polydispersity index, PDI = Mw / Mn (wherein Mn is the number average molecular weight and Mw is the weight average molecular weight) were determined according to ASTM D 6474-12 using gel permeation chromatography (GPC) using the following formula:

[0212]

[0213]

[0214]

[0215] For constant elution volume intervals AVi, where Ai and Mi are the chromatographic peak slice area and polyolefin molecular weight (Mw) associated with elution volume (Vi), respectively, where N is equal to the number of data points obtained from the chromatogram between the integration limits.

[0216] A high temperature GPC instrument equipped with either an infrared (IR) detector (IR4 or IR5 from PolymerChar (Valencia, Spain) or a differential refractometer (RI) from Agilent Technologies equipped with 3 Agilent-plgel Olexis and 1 Agilent-plgel Olexis Guard columns is used. 1,2,4-Trichlorobenzene (TCB) stabilized with 250 mg / L 2,6-di tert butyl-4-methylphenol is used as solvent and mobile phase. The chromatographic system is run at 160 °C at a constant flow rate of 1 mL / min. 209.5 μL of sample solution are injected for each analysis. Data collection is performed using an Agilent Cirrus 3.3 edition software or PolymerChar GPC-IR control software.

[0217] The column set is calibrated by using universal calibration with nineteen narrow MWD polystyrene (PS) standards in the range of 0.5 kg / mol to 11500 kg / mol. The PS standards are dissolved at room temperature for several hours. The conversion from polystyrene peak molecular weight to polyolefin molecular weight is done by using Mark Houwink equations and the following Mark Houwink constants:

[0218] K = 19 x 10-4dL / g, a = 0.655 PS -3 mL / g, a = 0.725 PS

[0219] K = 39 x 10-4dL / g, a = 0.725 PE -3 mL / g, a = 0.725 PE

[0220] The calibration data are fitted using a third order polynomial fit.

[0221] All samples are prepared at a concentration range of 0.5 - 1 mg / ml and dissolved at 160 °C for 3 hours (PE) under continuous slow shaking.

[0222] Cross-fractionation chromatography (CFC) determination of chemical heterogeneity ​​​​

[0223] The Chemi-Composition Distribution of polymers as well as the molecular weight distribution and the corresponding molecular weight averages (Mn, Mw and Mv) at a certain elution temperature (polymer crystallinity in solution) was determined by the fully automated Cross-Fractionation Chromatography (CFC) described by Ortin A., Monrabal B., Sancho-Tello J., Macromol. Symp., 2007, 257, 13-28.

[0224] Cross-Fractionation Chromatography (TREF x SEC) was performed using a CFC instrument (PolymerChar, Valencia, Spain). Concentration was monitored using a four wavelength IR5 infrared detector (PolymerChar, Valencia, Spain). About 40 mg of polymer sample was dissolved in 25 ml TCB at 150 °C for 150 minutes in a stainless steel vessel. After complete dissolution, a 0.5 ml aliquot was injected into the TREF column and stabilized at 110 °C for 60 minutes. Crystallization and precipitation of the polymer was performed by cooling at a constant cooling rate of 0.1 °C / min to 30 °C. Discontinuous elution steps were performed using the following temperature steps: (35, 40, 45, 50, 53, 56, 59, 62, 64, 66, 69, 72, 76, 79, 82, 85, 89, 91, 93, 95, 97, 100, 110 and 120).

[0225] In the two-dimensional GPC analysis, three PL Olexis columns and one Olexis Guard column from Agilent (Church Stretton, UK) were used as stationary phase. 1,2,4-Trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-Di-tert-butyl-4-methyl-phenol) was used as eluent at a constant flow rate of 1 mL / min at 150 °C. The column set was calibrated by using at least 15 narrow MWD polystyrene (PS) standards in the range from 0.5 kg / mol to 11500 kg / mol (PSS Standards, Mainz, Germany) by universal calibration (according to ISO 16014-2:2003). The PS molecular weights were converted to equivalent PE molecular weights using the following Mark Houwink constants.

[0226] K PS = 19 x 10 -3 mL / g, a PS = 0.655

[0227] K PE = 39 x 10 -3 mL / g, a PE = 0.725

[0228] The calibration data were fitted using a third order polynomial. The data were processed using the software provided by PolymerChar for the CFC instrument.

[0229] Soluble fraction SF @ 35 °C

[0230] Soluble fraction @ 35 °C is the polymer fraction eluted at 35 °C only in the CFC.

[0231] The ratio of Mw(Tp(LCF) / Mw(Tp(HCF)) and the ratio of the half-peak width Tp(LCF) / Tp(HCF)

[0232] To determine the weight average molecular weight at the peak of the low crystalline fraction (Mw(Tp(LCF)) or the high crystalline fraction (Mw(Tp(HCF)) and the half-peak width Tp(LCF) and Tp(HCF) in the first step, the a-TREF curve from the CFC analysis as described above is taken.

[0233] From the a-TREF curve the peak of the high crystalline fraction (HCF) peak (Tp(HCF)) and the low crystalline fraction (LCF) peak (Tp(LCF)) is determined. Tp(HCF) is eluted at a higher temperature than Tp(LCF) and less than 99 °C. Typically the high crystalline fraction ranges from 90 °C to 99 °C and the low crystalline fraction is the polymer fraction eluted at 35 °C to 90 °C. Figure 1 The a-TREF obtained from the CFC analysis of IE1 and CE1 is shown.

[0234] The half-peak width of the HCF and LCF is defined as the elution temperature difference between the front and the back temperature at half the maximum peak height, Tp(LCF) or Tp(HCF), respectively. If the separation between the peaks is not good, the corresponding front temperature is searched from 35 °C onwards and the back temperature at half the maximum is searched from 100 °C backwards. If the LCF and HCF are well separated, the back temperature is searched after the HCF.

[0235] In the next step the Mw at the elution temperature of Tp(LCF) and Tp(HCF) is determined. Therefore, the Mw at Tp(LCF) (Mw(Tp(LCF)) is calculated by linear interpolation between the Mw values of the GPC measurement at elution temperatures higher than Tp(LCF) and lower than Tp(LCF). This is achieved by using the "TREND" function in Excel, for example. The Mw at Tp(HCF) is determined in the same procedure.

[0236] From the determined Mw(Tp(LCF), Mw(Tp(HCF), the half-peak width (LCF), the half-peak width (HCF) and Tp(LCF) the following parameters can be calculated directly:

[0237] - Mw(Tp(LCF) / Mw(Tp(HCF)

[0238] - Half width Tp(LCF) / Tp(HCF)

[0239] Tensile modulus

[0240] Tensile modulus (E-Mod (MPa)) was measured according to ISO 527-3 on film samples of 40 pm thickness prepared as described in film sample preparation, in machine direction / transverse direction at a crosshead speed of 1 mm / min.

[0241] Instrumented Puncture Impact (IPT)

[0242] Instrumented Puncture Impact was determined by the free-falling dart method (ISO 7765 - Part 2). The maximum force, deflection at maximum force, energy at maximum force, puncture deflection and puncture energy were determined in instrumented puncture impact behavior test according to ISO 7765-2. The thickness of the blown film was 40 micrometers. The test conditions used were: impact speed of 4.4 m / s (or other), non-lubricated impact head of 20 mm diameter, at 23 ± 2 °C (or another temperature consistently ± 2 °C). The test pieces were clamped with support rings of 40 mm diameter.

[0243] Critical Shear Rate (CSR)

[0244] Determination of onset of flow instability at high shear rates according to ISO 11443 at 190 °C using a RHEOGRAPH 75 high pressure capillary rheometer Capillary L / D: 30 / 2.

[0245] Film sample preparation

[0246] Single layer test films of 40 pm thickness consisting of the inventive multimodal copolymer (P) and the respective comparative polymer were prepared using a W&H semi-commercial production line. The film samples were produced with a BUR of 1 :3. Melt temperature ~ 222 °C, frost line distance 700 mm, screw rotation speed 94 rpm, de-winding speed 18.8 m / min.

[0247] Experimental part

[0248] Cat. Example: Preparation of the catalyst (CAT1) of the inventive example

[0249] Loading of Si02:

[0250] Add 10 kg of silica (PQ Corporation ES757, calcined at 600 °C) from the feed tank and inertize in the reactor until the O2 level reaches below 2 ppm.

[0251] Preparation of MAO / tol / MC:

[0252] Into another reactor, 30wt% MAO in toluene (14.1 kg) was added from the balance, followed by toluene (4.0 kg) at 25 °C (oil bath temperature) and 95 rpm agitation. After the addition of toluene, the agitation speed was increased from 95 rpm to 200 rpm for 30 min. The metallocene rac-dimethylsilanediyl bis{2-(5-(trimethylsilyl)furan-2-yl)-4,5-dimethylcyclopentadien-1-yl}zirconium dichloride 477 g was added from the metal cylinder, followed by a rinse with 4 kg toluene (total toluene 8.0 kg). The reactor agitation speed was changed to 95 rpm for MC feeding, back to 200 rpm and for 3 h reaction time. After the reaction time, the MAO / tol / MC solution was transferred to the feed vessel.

[0253] Preparation of catalyst:

[0254] The reactor temperature was set to 10 °C (oil bath temperature) and agitated at 40 rpm for the addition of MAO / tol / MC. The MAO / tol / MC solution was added over 205 min (target 22.5 kg, actual 22.2 kg), followed by a 60 min agitation time (oil bath temperature set to 25 °C). After agitation, the “dry mix” was allowed to stabilize for 12 h at 25 °C (oil bath temperature) with 0 rpm agitation. The reactor was turned 20° (back and forth) and agitated a few rounds per hour at 5 rpm.

[0255] After stabilization, the catalyst was dried at 60 °C (oil bath temperature) under a nitrogen flow of 2 kg / h for 2 hours, followed by 13 hours under vacuum (same nitrogen flow with 5 rpm agitation). The dried catalyst was sampled and the HC content was measured in the glovebox using a Sartorius moisture analyser (model MA45) using thermogravimetry. The target HC level was <2% (actual 1.3%).

[0256] Catalyst of the comparative example (CAT2)

[0257] As catalyst CAT2, a supported catalyst containing aluminoxane was used, which contained the metallocene bis(1-methyl-3-n-butylcyclopentadienyl)zirconium(IV) chloride and had enhanced Activator technology.

[0258] Polymerisation: Inventive example: Inventive multimodal polyethylene copolymer (P) with 1-butene and 1-hexene comonomer (IE1) and comparative example (CE1)

[0259] The Borstar pilot plant has a three reactor setup (Loop 1 - Loop 2 - GPR1) and a prepolymerization loop reactor.

[0260] The inventive multimodal copolymer (P) of Example 1 (IE1) and the comparative example (CE1) were produced by using the polymerization conditions given in Table 1.

[0261] Table 1 : Polymerization conditions

[0262]

[0263] GPR ]]> ​ Temperature (°C) 75 75.0 Pressure (kPa) 2000 2000.0 H2 / C2 ratio (mol / kmol) 0.77 0.2 C6 / C2 ratio (mol / kmol) 10.06 30.3 Splitting (wt%) 58.1 62.8 MFR2 of GPR material (component (B)) (g / 10 min) 0.01 0.3 Density of GPR material (component (B)) (kg / m3) 898.9 902 C6 of GPR material (component (B)) (mol%) 4.99 4.62

[0264] The CE1 polymer was mixed with 2400 ppm of Irganox B561 and 270 ppm of Dynamar FX 5922, compounded and extruded into pellets by using a twin screw extruder ZSK18 under nitrogen atmosphere; melt temperature 192°C.

[0265] The IE1 polymer was mixed with only 2400 ppm of Irganox B561, compounded and extruded into pellets by using a twin screw extruder ZSK18 under nitrogen atmosphere; melt temperature 192°C.

[0266] Table 2: Material properties and film parameters of the inventive multimodal copolymer (P) and the comparative copolymer

[0267] Material IE1 CE1 MFR2(g / 10 min) (final) 0.63 0.99 Density (kg / m 3 )]]> 916.7 916.6 C4 (mol%) 0.6 0.2 C6 (mol%) 2.9 2.9 Mn (g / mol) 16000 25000 Mw (g / mol) 103000 105000 Mw / Mn 6.5 4.2 Mw(Tp(LCF) / Mw(Tp(HCF) * ]]> 4.96 1.3 Ratio of half width Tp(LCF) / half width Tp(HCF) * ]] 1.1 19.5 SF @ 35°C / density P ]] 0.003 0.007 CSR(s -1 )]]> 1008 130 Film properties IPT (J / mm) 130 106 Tensile modulus MPa (MD / TD) Definitions Catalyst Figure 1 Loading of Si02: Preparation of MAO / tol / MC: Preparation of catalyst: GPR Temperature (°C) Pressure (kPa) H2 / C2 ratio (mol / kmol) C6 / C2 ratio (mol / kmol) Splitting (wt%) MFR2 of GPR material (component (B)) (g / 10 min) Density of GPR material (component (B)) (kg / m3) C6 of GPR material (component (B)) (mol%) Material IE1 CE1 C4 (mol%) C6 (mol%) Mn (g / mol) Mw (g / mol) Mw / Mn Film properties IPT (J / mm) Tensile modulus MPa (MD / TD) Definitions Catalyst Figure 1 192 / 220 180 / 206

[0268] *: HCF: high crystalline fraction / LCF: low crystalline fraction. CFC data.

[0269] From the above table it is clear that films consisting of the inventive multimodal copolymer (P) have a higher impact strength in terms of IPT and tensile modulus than the comparative example.

[0270] Furthermore, such films can be processed with significantly higher critical shear rates.

[0271] The inventive polymers additionally have the beneficial low SF@35°C / density P .

Claims

1. A metallocene catalysed multimodal polyethylene copolymer (P) consisting of (i) 35.0 to 50.0 wt% of an ethylene-1-butene polymer component (A), and (ii) 50.0 to 65.0 wt% of an ethylene-1-hexene polymer component (B), wherein the ethylene-1-butene polymer component (A) has a MFR2 determined according to ISO 1133 at 190 °C under a load of 2.16 kg in the range of 30.0 to 300.0 g / 10 min, a 1-butene content in the range of 0.1 to 3.0 mol% based on the ethylene-1-butene polymer component (A); wherein the ethylene-1-butene polymer component (A) consists of an ethylene-1-butene polymer fraction (A-1) and an ethylene-1-butene polymer fraction (A-2) with a MFR2 determined according to ISO 1133 at 190 °C under a load of 2.16 kg in the range of 0.1 to 3.0 g / 10 min, and a MFR2 determined according to ISO 1133 at 190 °C under a load of 2.16 kg in the range of 0.1 to 3.0 g / 10 min, wherein the ethylene-1-hexene polymer component (B) has a MFR2 determined according to ISO 1133 at 190 °C under a load of 2.16 kg in the range of 0.001 to 1.0 g / 10 min, a 1-hexene content in the range of 2.5 to 10.0 mol% based on the ethylene-1-hexene polymer compound (B), wherein the multimodal polyethylene copolymer (P) has a MFR2 determined according to ISO 1133 at 190 °C under a load of 2.16 kg in the range of 0.1 to 3.0 g / 10 min, a ratio of the molecular weight (Mw) of the low crystalline fraction (LCF) to the molecular weight (Mw) of the high crystalline fraction (HCF) in the range of 2.5 to 10.0, a ratio of the half height width Tp(LCF) / the half height width Tp(HCF) in the range of 0.9-5.9, and a ratio of the soluble fraction at 35 °C to the density of the multimodal polyethylene copolymer (P) of below 0.

007.

2. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 1, 3. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 1 or 2, wherein the MFR2 determined according to ISO 1133 at 190 °C under a load of 2.16 kg of the ethylene polymer component (A) is in the range of 35.0 to 250.0 g / 10 min, and the MFR2 determined according to ISO 1133 at 190 °C under a load of 2.16 kg of the ethylene polymer component (B) is in the range of 0.005 to 0.9 g / 10 min.

4. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 3, wherein the MFR2 determined according to ISO 1133 at 190 °C under a load of 2.16 kg of the ethylene polymer component (A) is in the range of 40.0 to 200.0 g / 10 min. density in the range of 930 to 960 kg / m 3 of the range of 930 to 960 kg / m ​ ​ ​ ​ density in the range of 880 to 920 kg / m 3 of 880 to 920 kg / m ​ ​ ​ density in the range of 910 to 945 kg / m 3 of the range 910 to 945 kg / m ​ ​ ​ ​ SF @ 35°C / density P The soluble fraction at 35°C was determined using cross-fractionation chromatography (CFC). ​ wherein the density of fractions (A-1) and (A-2) ranges from 925 to 960 kg / m3 3 MFR2determined according to ISO 1133 at a load of 2.16 kg at 190 °C ranges from 30 to 300 g / 10 min, wherein the density of the ethylene polymer fractions (A-1) and (A-2) and / or the MFR2determined according to ISO 1133 at a load of 2.16 kg at 190 °C are the same or different. ​ ​ ​ 5. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 3, wherein the ethylene polymer component (A) has a MFR2 determined according to ISO 1133 at a load of 2.16 kg at 190 °C in the range of 45 to 150.0 g / 10 min.

6. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 3, wherein the ethylene polymer component (B) has a MFR2 determined according to ISO 1133 at a load of 2.16 kg at 190 °C in the range of 0.008 to 0.7 g / 10 min.

7. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 3, wherein the ethylene polymer component (B) has a MFR2 determined according to ISO 1133 at a load of 2.16 kg at 190 °C in the range of 0.01 to 0.5 g / 10 min.

8. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 1 or 2, wherein the total amount of 1-butene ranges from 0.1 to 1.0 mol% based on the multimodal polyethylene copolymer (P), and / or the total amount of 1-hexene ranges from 1.5 to 8.0 mol% based on the multimodal polyethylene copolymer (P).

9. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 8, wherein the total amount of 1-butene ranges from 0.2 to 0.8 mol% based on the multimodal polyethylene copolymer (P).

10. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 8, wherein the total amount of 1-butene ranges from 0.3 to 0.7 mol% based on the multimodal polyethylene copolymer (P).

11. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 8, wherein the total amount of 1-hexene ranges from 2.0 to 6.0 mol% based on the multimodal polyethylene copolymer (P).

12. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 8, wherein the total amount of 1-hexene ranges from 2.2 to 4.0 mol% based on the multimodal polyethylene copolymer (P).

13. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 1 or 2, wherein the total amount of 1-butene present in the ethylene-1-butene polymer component (A) (mol%) ranges from 0.5 to 2.6 mol% based on the ethylene-1-butene polymer component (A), and the total amount of 1-hexene present in the ethylene-1-hexene polymer component (B) ranges from 3.0 to 8.0 mol% based on the ethylene-1-hexene polymer component (B).

14. The metallocene-catalysed multimodal polyethylene copolymer (P) according to claim 13, wherein the total amount of 1-butene present in the ethylene-1-butene polymer component (A) (mol%) ranges from 0.8 to 2.0 mol% based on the ethylene-1-butene polymer component (A). ​ ​ 15. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 13, wherein the total amount of 1 -butene present in the ethylene-1 -butene polymer component (A) (mol%) ranges from 1.0 to 1.8 mol% based on the ethylene-1 -butene polymer component (A).

16. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 13, wherein the total amount of 1 -hexene present in the ethylene-1 -hexene polymer component (B) ranges from 3.5 to 6.0 mol% based on the ethylene-1 -hexene polymer component (B).

17. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 1 or 2, wherein the ethylene polymer component (A) is present in an amount of 35.0 to 50.0 wt% based on the multimodal polyethylene copolymer (P), and the ethylene polymer component (B) is present in an amount of 50.0 to 65.0 wt% based on the multimodal polyethylene copolymer (P).

18. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 17, wherein the ethylene polymer component (A) is present in an amount of 36.0 to 48.0 wt% based on the multimodal polyethylene copolymer (P).

19. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 17, wherein the ethylene polymer component (A) is present in an amount of 38.0 to 45.0 wt% based on the multimodal polyethylene copolymer (P).

20. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 17, wherein the ethylene polymer component (B) is present in an amount of 52.0 to 64.0 wt% based on the multimodal polyethylene copolymer (P).

21. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 17, wherein the ethylene polymer component (B) is present in an amount of 55.0 to 62.0 wt% based on the multimodal polyethylene copolymer (P).

22. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 1 or 2, wherein the multimodal polyethylene copolymer (P) is produced in the presence of a metallocene complex of formula (I): each Het is independently a monocyclic heteroaromatic radical containing at least one heteroatom selected from O or S; M is Ti, Zr or Hf; wherein each X is independently a halogen atom, C 1-6 -alkyl, C 1-6 -alkoxy, phenyl or benzyl; each n is 1 to 2; L is -R'2Si-, wherein each R' is independently C 1-20 - a hydrocarbon group or C 1-10 - an alkyl group; each p is 0 to 1. Each R 1 Same or different, is C 1-6 -alkyl or C 1-6 -alkoxy group; 27. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 1 or 2, wherein the multimodal polyethylene copolymer (P) has a ratio of the molecular weight (Mw) of the low crystalline fraction (LCF) to the molecular weight (Mw) of the high crystalline fraction (HCF) in the range of 3.0 to 8.0, Mw(Tp(LCF) / Mw(Tp(HCF), and / or a ratio of the half-peak width Tp(LCF) to the half-peak width Tp(HCF) in the range of 0.9 to 4.

0. Each R 2 Same or different, is C 1-6 -alkyl, C 1-6 -alkoxy or -Si(R)3 group; each R is optionally substituted with 1 to 3 C 1-6 - alkyl substituted C 1-10 - alkyl or phenyl; and ​ 23. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 1 or 2, wherein the multimodal polyethylene copolymer (P) has an improved processability, which is indicated by a critical shear rate (CSR) determined according to ISO 11443, which is at least 200 s -1 up to 1500 s -1 .

24. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 23, wherein the multimodal polyethylene copolymer (P) has an improved processability, which is indicated by a critical shear rate (CSR) determined according to ISO 11443, which is at least 500 s -1 .

25. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 23, wherein the multimodal polyethylene copolymer (P) has an improved processability, which is indicated by a critical shear rate (CSR) determined according to ISO 11443, which is at least 800 s -1 .

26. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 23, wherein the multimodal polyethylene copolymer (P) has an improved processability, which is indicated by a critical shear rate (CSR) determined according to ISO 11443, which is at least 1000 s -1 and at most 1300 s -1 . ​ ​ 28. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 27, wherein the metallocene catalysed multimodal polyethylene copolymer (P) has a ratio of the molecular weight (Mw) of the low crystalline fraction (LCF) to the molecular weight (Mw) of the high crystalline fraction (HCF) in the range of 3.5 to 6.5, Mw(Tp(LCF) / Mw(Tp(HCF).

29. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 27, wherein the metallocene catalysed multimodal polyethylene copolymer (P) has a ratio of the half peak height width Tp(LCF) to the half peak height width Tp(HCF) in the range of 1.0 to 2.

0.

30. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to claim 1 or 2, wherein the ratio of the soluble portion of the multimodal polyethylene copolymer (P) at 35°C to the density of the multimodal polyethylene copolymer (P), SF@35°C / density P The soluble fraction at 35°C was determined by cross-fractional chromatography (CFC) if the soluble fraction was less than 0.

006.

31. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to claim 30, wherein the ratio of the soluble portion of the multimodal polyethylene copolymer (P) at 35°C to the density of the multimodal polyethylene copolymer (P), SF@35°C / density P The soluble fraction at 35°C was determined by cross-fractional chromatography (CFC) if the soluble fraction was less than 0.

005.

32. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 30, wherein the ratio of the soluble fraction at 35 °C to the density of the multimodal polyethylene copolymer (P), SF@35 °C / density P In the range of 0.001 to below 0.006, the soluble fraction at 35 °C is determined with Cross-Fractionation Chromatography (CFC).

33. The metallocene catalysed multimodal polyethylene copolymer (P) according to claim 30, wherein the ratio of the soluble fraction at 35 °C to the density of the multimodal polyethylene copolymer (P), SF@35 °C / density P In the range of 0.001 to below 0.005, the soluble fraction at 35 °C is determined with Cross-Fractionation Chromatography (CFC).

34. A film comprising the metallocene catalysed multimodal polyethylene copolymer (P) according to any one of the preceding claims 1 to 33.

35. The film according to claim 34, wherein the film comprises at least one layer comprising the metallocene catalysed multimodal polyethylene copolymer (P), wherein the at least one layer comprises at least 50 wt% of the metallocene catalysed multimodal polyethylene copolymer (P) according to any one of the preceding claims 1 to 33.

36. The film according to claim 35, wherein the film comprises at least one layer comprising the metallocene catalysed multimodal polyethylene copolymer (P), wherein the at least one layer comprises at least 60 wt% of the metallocene catalysed multimodal polyethylene copolymer (P) according to any one of the preceding claims 1 to 33.

37. The film according to claim 35, wherein the film comprises at least one layer comprising the metallocene catalysed multimodal polyethylene copolymer (P), wherein the at least one layer comprises at least 70 wt% of the metallocene catalysed multimodal polyethylene copolymer (P) according to any one of the preceding claims 1 to 33.

38. The film according to claim 35, wherein the film comprises at least one layer comprising the metallocene catalysed multimodal polyethylene copolymer (P), wherein the at least one layer comprises at least 80 wt% of the metallocene catalysed multimodal polyethylene copolymer (P) according to any one of the preceding claims 1 to 33.

39. The film according to claim 34 or 35, wherein the film is characterized by an impact strength in instrumented puncture test (IPT) determined according to ISO 7765-2 on a 40 pm monolayer test blown film of at least 110 J / mm to 300 J / mm.

40. The film according to claim 39, wherein the film is characterized by an impact strength in instrumented puncture test (IPT) determined according to ISO 7765-2 on a 40 pm monolayer test blown film of 115 J / mm to 250 J / mm.

41. The film according to claim 39, wherein the film is characterized by an impact strength in instrumented puncture test (IPT) determined according to ISO 7765-2 on a 40 pm monolayer test blown film of 120 J / mm to 200 J / mm.

42. The film according to claim 34 or 35, wherein the film is characterized by a tensile modulus in the machine direction (MD) and transverse direction (TD) ranging from > 160 MPa to 350 MPa measured on a 40 pm monolayer test blown film according to the method of ISO 527-3.

43. The film according to claim 42, wherein the film is characterized by a tensile modulus in the machine direction (MD) and transverse direction (TD) ranging from 180 MPa to 300 MPa measured on a 40 pm monolayer test blown film according to the method of ISO 527-3.

44. Use of the film according to any of the preceding claims 34 to 43 as a packaging material.

45. Use of the film according to any of the preceding claims 34 to 43 as a packaging material for food and / or medical products.

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