Polyethylene copolymers for film layers

Abstract

The present invention relates to metallocene catalyzed multimodal polyethylene copolymers (P), the use of multimodal ethylene copolymers (P) in membrane applications, and membranes comprising the polymer compositions of the invention.

Description

Technical Field

[0001] This invention relates to a metallocene-catalyzed multimodal polyethylene copolymer (P), the use of the multimodal polyethylene copolymer (P) in membrane applications, and membranes comprising the polymer composition of this invention. Background Technology

[0002] Existing mLLDPE (metallocene-catalyzed linear low-density polyethylene) is widely used in various aspects of daily life, such as packaging, due to its excellent cost-effectiveness. A well-known drawback is its narrow molecular weight distribution, resulting in lower shear thinning, which leads to problems in membrane processing, such as limiting production volume.

[0003] Furthermore, higher production volumes in the plastics processing industry are limited by melt flow instability, which alters the appearance and performance of the final product and has economic and environmental consequences.

[0004] Single-peak mLLDPEs are typically used in membrane applications. For example, single-peak LLDPEs offer good optical properties (e.g., low haze), but melt processing of such polymers in production is often unsatisfactory, potentially leading to quality issues in the final product. Multi-peak mLLDPEs with two or more different polymer components are easier to process, but melt homogenization of multi-peak PEs can be problematic, resulting in a heterogeneous final product, manifested as, for example, a higher gel content.

[0005] Films made from mLLDPE resin are known to have excellent mechanical properties, such as impact resistance as measured in dart impact (DDI) tests, but usually at the cost of poor extrusion processability, melt strength and bubble stability.

[0006] In some end-use applications (such as blown film applications), it would be beneficial to have the properties of metallocene-catalyzed LLDPE copolymers, along with improved processability, melt strength, and bubble stability.

[0007] A common solution to improve the processability of polymer melts is to add so-called processing aids. Unfortunately, most suitable processing aids are fluoropolymers, due to the potential health risks associated with their fluorine content, both for human and environmental health.

[0008] As mentioned above, processability is also affected by molecular structure. Multimodal PE polymers with two or more different polymer components are known to be easier to process, but melt homogenization of multimodal PEs may be problematic, leading to heterogeneity in the final product, such as a higher gel content.

[0009] Multimodal PE polymers are known in the art.

[0010] Borealis discloses a method for preparing multi-peaked PE polymers in the presence of a silica-supported metallocene catalyst based on the metallocene complex bis(1-methyl-3-n-butylcyclopentadienyl)zirconium dichloride (IV) in two loop reactors and one gas-phase reactor.

[0011] The total density of the polymer produced in the examples is 938 or 939 kg / m³. 3 The MFR2 (190 °C, 2.16 kg, ISO 1133) of the polymer component produced in the first loop reactor was approximately 22 or 23 g / 10 min.

[0012] There is no mention of membrane properties, such as impact strength, seal initiation temperature, or processing parameters, such as melt pressure.

[0013] This method is also disclosed in WO 2021009192. The polymers produced in the examples have even higher densities (951 kg / m³). 3 The MFR2 (190 °C, 2.16 kg, ISO 1133) of the polymer component produced in the first loop reactor was 32 g / 10 min.

[0014] It also makes no mention of membrane properties, such as impact strength, seal initiation temperature, or processing parameters, such as melt pressure.

[0015] WO 2023012254 discloses a method for preparing multi-peaked PE polymers in two loop reactors and one gas-phase reactor in the presence of a silica-supported metallocene catalyst based on the metallocene complex racemic-dimethylsilanediylbis{2-(5-(trimethylsilyl)furan-2-yl)-4,5-dimethylcyclopentadien-1-yl}zirconium dichloride.

[0016] In the invention, the MFR2 of the polymer fractions produced in the two loop reactors are only slightly different, resulting in a ratio MFR2(A-2) / MFR2(A-1) of 1.04. This is because the polymers in the two loop reactors are designed to have a basically unimodal distribution.

[0017] Membrane properties, such as impact strength and seal initiation temperature, were not mentioned.

[0018] WO 2023012256 also discloses a method for preparing multi-peak PE polymers in two loop reactors and one gas-phase reactor in the presence of a silica-supported metallocene catalyst based on the metallocene complex racemic-dimethylsilanediylbis{2-(5-(trimethylsilyl)furan-2-yl)-4,5-dimethylcyclopentadien-1-yl}zirconium dichloride.

[0019] In the invention, the MFR2 of the polymer fractions produced in the two loop reactors are only slightly different, resulting in a ratio of MFR2(A-2) / MFR2(A-1) of 1.04 to 2.8. This is because the polymers in the two loop reactors are designed to have a basically unimodal distribution.

[0020] Sealing performance was not mentioned.

[0021] EP3538572 describes an ethylene-based polymer with improved processability and melt strength, while also exhibiting good impact and tear strength. These polymers are prepared using a dual-catalyst system, and their ATREF spectra are characterized by a peak ATREF temperature (the temperature of the highest peak on the ATREF curve) of approximately 68 to approximately 78 °C. The ATREF curve of the inventive examples shows only a single significant peak. Example 12 is a comparative example, whose TREF curve shows a three-peak distribution, but this polymer was not used to prepare a film.

[0022] According to the specification, films made from such polymers may contain one or more additives, non-limiting examples of which include antioxidants, acid scavengers, antiblocking agents, slip agents, colorants, fillers, processing aids, UV inhibitors, and combinations thereof.

[0023] The goal is to maximize the processability of multimodal PE polymers, achieving good processability without the addition of processing aids. Undoubtedly, any actions that improve polymer properties to enhance processability should not compromise the performance of the final film.

[0024] The inventors have now discovered that metallocene-catalyzed multimodal polyethylene copolymers (P) prepared with specific metallocene catalysts and having specific polymer structure designs can simultaneously possess good processability (in terms of melt pressure) and low sealing initiation temperature, while maintaining high levels of mechanical properties (e.g., impact strength).

[0025] According to the present invention, the ethylene polymer described herein has a unique ATREF spectrum. Summary of the Invention

[0026] Therefore, the present invention relates to a metallocene-catalyzed multimodal polyethylene copolymer (P), wherein the multimodal polyethylene copolymer (P) is a terpolymer of ethylene and two different C3-C8 α-olefin comonomers, and the multimodal polyethylene copolymer (P) has the following characteristics:

[0027] Density (ISO 1183) is 910 to 925 kg / m³ 3 ;

[0028] MFR2 (190 °C, 2.16 kg, ISO 1133) is 0.3 to 1.5 g / 10 min; and

[0029] The multimodal polyethylene copolymer (P) is further characterized in that the ATREF spectrum measured as described in the experimental section shows a three-peak chemical composition distribution (CCD), and the multimodal polyethylene copolymer (P) is composed of the following:

[0030] a) 35.0 wt% to 50.0 wt% of a low crystallinity fraction (LCF) based on multimodal polyethylene copolymer (P), said low crystallinity fraction (LCF) eluted between >35 and 70 °C;

[0031] b) 20.0 wt% to 37.0 wt% of a medium crystalline fraction (MCF) based on multimodal polyethylene copolymer (P), said medium crystalline fraction (MCF) eluted between >70 and 90 °C;

[0032] c) 3.0 wt% to 30.0 wt% of a highly crystalline fraction (HCF) based on multimodal polyethylene copolymer (P), said highly crystalline fraction (HCF) eluted between >90 and 105 °C;

[0033] d) The total amount of low crystallinity fraction (LCF), medium crystallinity fraction (MCF), and high crystallinity fraction (HCF) is at least 95.0 wt%;

[0034] e) The remaining portion of the multimodal polyethylene copolymer (P) is eluted at a temperature ≤35 °C; and

[0035] The ratio of medium-crystallization fraction to high-crystallization fraction (MCF / HCF) is 0.6 to 3.0.

[0036] In one embodiment of the invention, the multimodal polyethylene copolymer (P) is a terpolymer of ethylene and two different C3-C8 α-olefin comonomers, and the density (ISO 1183) of the multimodal polyethylene copolymer (P) is 910 to 925 kg / m³. 3 MFR2 (190 °C, 2.16 kg, ISO 1133) was 0.3 to 1.5 g / 10 min, determined quantitatively as described in the experimental section. 13 C{ 1 The total comonomer content, as determined by ¹H NMR, is 1.1 to 8.0 mol%, and the multimodal polyethylene copolymer (P) is composed of an in-situ blend of the following components:

[0037] (i) an ethylene copolymer component (A), said ethylene copolymer component (A) being composed of an ethylene polymer fraction (A-1) and an ethylene polymer fraction (A-2); and

[0038] (ii) Ethylene copolymer component (B);

[0039] Wherein, the ethylene copolymer component (A) is a copolymer of ethylene and one or two C3-C8 α-olefin comonomers, and the total content of the comonomers in the ethylene copolymer component (A) is 0.2 to 3.0 mol%, based on the total weight of the ethylene copolymer component (A).

[0040] Based on the total weight of the ethylene polymer fraction (A-1), the ethylene polymer fraction (A-1) was quantitatively analyzed as described in the experimental section. 13 C{ 1 The comonomer content measured by ¹H NMR ranges from 0.1 to 2.0 mol%. The comonomer content of ethylene polymer fraction (A-2) is higher than that of ethylene polymer fraction (A-1), and the difference in comonomer content between ethylene polymer fraction (A-2) and ethylene polymer fraction (A-1) is 0.3 to 3.0 mol%. The comonomer content of ethylene polymer fraction (A-2) is calculated according to formula (Ia):

[0041] ,

[0042] In the formula

[0043] x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A).

[0044] cc(A-2) represents the calculated comonomer content of the ethylene polymer fraction (A-2).

[0045] cc(A-1) represents the comonomer content of the ethylene polymer fraction (A-1).

[0046] cc(A) represents the comonomer content of the ethylene copolymer component (A).

[0047] Among them, cc(A-1) and cc(A) are quantified as described in the experimental section. 13 C{ 1 Measured by H NMR;

[0048] Ethylene copolymer component (B) is a copolymer of ethylene and one or two C3-C8 α-olefin comonomers. Ethylene copolymer component (B) contains at least one comonomer different from the comonomer of ethylene copolymer component (A). The comonomer content of ethylene copolymer component (B) is higher than that of ethylene copolymer component (A). The comonomer content of ethylene copolymer component (B) is calculated according to formula (Ib):

[0049] ,

[0050] In the formula,

[0051] x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P).

[0052] cc(B) represents the calculated comonomer content of the ethylene copolymer component (B).

[0053] cc(A) represents the comonomer content of the ethylene copolymer component (A).

[0054] cc(P) represents the comonomer content of the multimodal polyethylene copolymer (P).

[0055] Among them, cc(A) and cc(P) are quantified as described in the experimental section. 13 C{ 1 Measured by H NMR.

[0056] In another embodiment of the invention, the multimodal polyethylene copolymer (P) is a terpolymer of ethylene and two different C3-C8 α-olefin comonomers, and the density (ISO 1183) of the multimodal polyethylene copolymer (P) is 910 to 925 kg / m³. 3 The MFR2 (190 °C, 2.16 kg, ISO 1133) is 0.3 to 1.5 g / 10 min, and the multimodal polyethylene copolymer (P) consists of an in-situ blend of the following components:

[0057] (i) an ethylene copolymer component (A), said ethylene copolymer component (A) being composed of an ethylene polymer fraction (A-1) and an ethylene polymer fraction (A-2); and

[0058] (ii) Ethylene copolymer component (B);

[0059] The density (ISO 1183) of the ethylene copolymer component (A) is 930 to 950 kg / m³. 3 MFR2 (190 °C, 2.16 kg, ISO 1133) ranges from 0.2 to 500 g / 10 min;

[0060] The densities (ISO 1183) of fractions (A-1) and (A-2) are 930 to 950 kg / m³. 3 ;

[0061] The MFR2 (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-1) is 0.1 to 100 g / 10 min;

[0062] The MFR2 (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-2) is higher than that of the ethylene polymer fraction (A-1);

[0063] The ratio of MFR2 (190 °C, 2.16 kg, ISO 1133) of ethylene polymer fraction (A-2) to MFR2 (190 °C, 2.16 kg, ISO 1133) of ethylene polymer fraction (A-1) is 4 to 200.

[0064] The MFR2 of the ethylene polymer fraction (A-2) is calculated according to formula (II-a):

[0065]

[0066] In the formula,

[0067] x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A).

[0068] MFR(A-2) is the calculated MFR2 of the ethylene polymer fraction (A-2).

[0069] MFR(A-1) is MFR2 of the ethylene polymer fraction (A-1) (190 °C, 2.16 kg, ISO 1133).

[0070] MFR(A) is MFR2 of ethylene copolymer component (A) (190 °C, 2.16 kg, ISO 1133).

[0071] The density and MFR2 of the ethylene copolymer component (B) are lower than those of the ethylene copolymer component (A).

[0072] MFR2 is calculated according to formula (II-b):

[0073]

[0074] In the formula,

[0075] x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P).

[0076] MFR(B) is the calculated MFR2 of the ethylene copolymer component (B).

[0077] MFR(P) is MFR2 of multimodal polyethylene copolymer (P) (190 °C, 2.16 kg, ISO 1133).

[0078] MFR(A) is MFR2 of ethylene copolymer component (A) (190 °C, 2.16 kg, ISO 1133).

[0079] Density is calculated according to formula (III):

[0080] ,

[0081] In the formula,

[0082] x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P).

[0083] Density (B) is the calculated density of the ethylene copolymer component (B).

[0084] Density (A) is the density of the ethylene copolymer component (A) (ISO 1183).

[0085] Density (P) is the density of the multimodal polyethylene copolymer (P) (ISO 1183).

[0086] In another embodiment of the invention, the seal initiation temperature (SIT) measured using a 40 µm test blown film made of multimodal polyethylene copolymer (P) as described in the experimental section satisfies inequality (X):

[0087]

[0088] In the formula, MFR2HMW is the MFR2 of the ethylene copolymer component (B) (190 °C, 2.16 kg, ISO 1133), calculated as described above using formula (II-b).

[0089] Surprisingly, the multimodal polyethylene copolymer (P) of the present invention can be processed into films without the addition of processing aids, while having a lower sealing initiation temperature and maintaining high mechanical properties (especially dart impact strength) compared to bimodal polymers with similar MFR2HMW and density.

[0090] The present invention also relates to a membrane comprising a multimodal polyethylene copolymer (P) and the use of the membrane. Detailed Implementation

[0091] definition

[0092] In this application specification and claims, the term "comprising" does not exclude other elements not specifically described that have an important or secondary functional role. For the purposes of this invention, the term "consisting of" is considered the preferred embodiment of the term "comprising". If a group is defined below as including at least a certain number of embodiments, it should also be understood as disclosing a group preferably consisting only of these embodiments.

[0093] For the purposes of this invention, the term "consisting of an in-situ blend of (i) and (ii)" does not exclude the presence of any additives that may be added to the multimodal polyethylene copolymer (P). This term refers only to the quantity of the polymer components, i.e., copolymer component (A) and copolymer component (B).

[0094] Whenever the terms “include” or “have” are used, they should be understood as equivalent to “include” as defined above.

[0095] When referring to a singular noun, the plural form of the noun is included when using an indefinite or definite article (such as "a," "a kind," or "the").

[0096] In this invention, metallocene-catalyzed multimodal polyethylene copolymers are defined as multimodal polyethylene copolymers (P) that have been produced in the presence of a metallocene catalyst.

[0097] Polyethylene polymers prepared using single-site catalysis (e.g., metallocene catalysis) rather than Ziegler-Natta catalysis exhibit characterizing features that distinguish them from Ziegler-Natta materials. In particular, the comonomer distribution is more homogeneous. This can be demonstrated using TREF or Crystaf techniques. Catalyst residues can also indicate the catalyst used. For example, Ziegler-Natta catalysts do not contain Zr or Group IV (Hf) metals.

[0098] In this paper, in the case of multimodal polyethylene copolymers (P), the term "multimodal" refers to the fact that the ethylene copolymer components (A) and (B) of the ethylene polymer fractions (A-1) and (A-2) are respectively multimodal in terms of comonomer content and melt flow rate (MFR), i.e., the ethylene copolymer components (A) and (B), as well as the fractions (A-1) and (A-2), have different MFR values ​​and comonomer contents. The multimodal polyethylene copolymer (P) may further exhibit a multimodal distribution with respect to one or more other properties between the ethylene copolymer components (A) and (B), as described below.

[0099] For the purposes of this invention, “a metallocene-catalyzed multimodal polyethylene copolymer (P) composed of an in-situ blend of ethylene copolymer component (A) and ethylene copolymer component (B)” means that the multimodal polyethylene copolymer (P) is produced by a sequential polymerization process of at least two stages, wherein component (A) is first produced, and then component (B) is produced in a subsequent polymerization step in the presence of component (A) to obtain the multimodal polyethylene copolymer (P).

[0100] In this document, the multimodal polyethylene copolymer (P) as defined above, below or in the claims of the present invention is also simply referred to as "multimodal PE" or "multimodal copolymer (P)".

[0101] The following descriptions of multimodal PE and its ethylene polymer components (A) and (B), as well as ethylene polymer fractions (A-1) and (A-2), and preferred embodiments, properties, and subgroups (including their preferred ranges) of the membrane of the present invention can be summarized independently, and thus can be used in any order or combination to further define the preferred embodiments of multimodal PE and the articles of the present invention.

[0102] Multimodal polyethylene copolymer (P), and ethylene copolymer components (A) and (B), and ethylene polymer fractions (A-1) and (A-2).

[0103] According to the present invention, the metallocene-catalyzed multimodal polyethylene copolymer (P) is characterized by a specific ATREF spectrum as measured as described in the experimental section, showing a three-peak chemical composition distribution (CCD).

[0104] Specific ATREF spectra show:

[0105] a) Based on multimodal polyethylene copolymer (P), 35.0 to 50.0 wt%, preferably 38.0 to 50.0 wt%, more preferably 40.0 to 50.0 wt%, of a low crystallinity fraction (LCF) eluted between >35 and 70 °C;

[0106] b) Based on multimodal polyethylene copolymer (P), 20.0 to 37.0 wt%, preferably 22.0 to 37.0 wt%, more preferably 25.0 to 37.0 wt%, of a medium crystalline fraction (MCF) eluted at a temperature between >70 and 90 °C;

[0107] c) Based on multimodal polyethylene copolymer (P), 3.0 to 30.0 wt%, preferably 8.0 to 28.0 wt%, more preferably 10.0 to 26.0 wt%, of a highly crystalline fraction (HCF) eluted at a temperature between >90 and 105 °C;

[0108] d) The total content of low crystallinity fraction (LCF), medium crystallinity fraction (MCF), and high crystallinity fraction (HCF) is at least 95.0 wt%, preferably at least 97.0 wt%, and more preferably at least 97.5 wt%;

[0109] e) The remaining portion of the multimodal polyethylene copolymer (P) was eluted at a temperature of ≤35 °C.

[0110] The total amount of low crystallinity fraction (LCF), medium crystallinity fraction (MCF), high crystallinity fraction (HCF) and e (i.e., the portion of multi-peak polyethylene copolymer (P) eluted at a temperature ≤35 °C) is 100 wt%.

[0111] The ratio of medium-crystallization fraction to high-crystallization fraction (MCF / HCF) is 0.6 to 3.0, preferably 0.8 to 2.8, and more preferably 1.0 to 2.6.

[0112] Definitions of high crystallinity fraction (HCF), medium crystallinity fraction (MCF), and low crystallinity fraction (LCF):

[0113] High crystallinity fraction (HCF) is the amount of polymer fraction with a crystallization temperature between >90 and 105 °C, expressed in wt%, and the high crystallinity fraction (HCF) mainly comprises homopolymer-polyethylene chains or chains with very low branching content.

[0114] Medium crystallization fraction (MCF) is the amount of polymer fraction with a crystallization temperature between >70 and 90 °C, expressed in wt%.

[0115] Low crystallinity fraction (LCF) is the amount of polymer fraction with a crystallization temperature between >35 and 70 °C, expressed in wt%.

[0116] In one embodiment of the present invention, the metallocene-catalyzed multimodal polyethylene copolymer (P) is a terpolymer of ethylene and two C3-C8 α-olefin comonomers, wherein the multimodal polyethylene copolymer (P) is composed of an in-situ blend of the following components:

[0117] (i) an ethylene copolymer component (A), said ethylene copolymer component (A) being composed of an ethylene polymer fraction (A-1) and an ethylene polymer fraction (A-2); and

[0118] (ii) Ethylene copolymer component (B).

[0119] Preferably, the multimodal polyethylene copolymer (P) produced by metallocene is composed of the following components:

[0120] (i) Based on the total weight of the multimodal polyethylene copolymer (P), 35.0 to 50.0 wt%, more preferably 38.0 to 48.0 wt%, of the ethylene copolymer component (A); and

[0121] (ii) Based on the total weight of the multimodal polyethylene copolymer (P), 50.0 to 65.0 wt%, more preferably 52.0 to 62.0 wt%, of the ethylene copolymer component (B).

[0122] The total amount of (A) and (B) is 100.0 wt%.

[0123] Within the scope of this invention, the weight ratio of the first and second ethylene polymer fractions (A-1 and A-2) of the ethylene copolymer component (A) is 4:1 to 1:4, for example 3:1 to 1:3, or 2:1 to 1:2, or 1:1.

[0124] This paper refers to the multimodal polyethylene copolymer (P) produced by metallocene as "multimodal" because the ethylene copolymer component (A) (correspondingly, ethylene polymer fractions (A-1) and (A-2)) and ethylene copolymer component (B) have been produced under different polymerization conditions, resulting in different comonomer contents and different melt flow rates (MFRs, e.g., MFR2). That is, multimodal PE is multimodal, at least in terms of the differences in comonomer contents and MFR2 between ethylene copolymer components (A) and (B), as well as between ethylene polymer fractions (A-1) and (A-2).

[0125] As described above, the multimodal polyethylene copolymer (P) produced by metallocene is a terpolymer of ethylene and two different C3-C8 α-olefin comonomers, wherein the multimodal polyethylene copolymer (P) is composed of an in-situ blend of the following components:

[0126] (i) an ethylene copolymer component (A), said ethylene copolymer component (A) being composed of an ethylene polymer fraction (A-1) and an ethylene polymer fraction (A-2); and

[0127] (ii) Ethylene copolymer component (B).

[0128] For example, the C3-C8 α-olefin comonomers are propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene. Preferred comonomers are 1-butene, 1-hexene, and 1-octene. Particularly preferred are 1-butene and 1-hexene.

[0129] The ethylene copolymer component (A) is a copolymer of ethylene with one or two C3-C8 α-olefin comonomers.

[0130] Therefore, the ethylene copolymer component (A) can be a copolymer of ethylene and a C3-C8 α-olefin comonomer, or a terpolymer of ethylene and two C3-C8 α-olefin comonomers.

[0131] Preferably, the ethylene copolymer component (A) is a copolymer of ethylene and a comonomer selected from 1-butene, 1-hexene and 1-octene (more preferably, selected from 1-butene and 1-hexene).

[0132] In a preferred embodiment, the ethylene copolymer component (A) is a copolymer of ethylene and 1-butene.

[0133] Since the ethylene copolymer component (A) is composed of ethylene polymer fraction (A-1) and ethylene polymer fraction (A-2), these two fractions may have the same type of C3-C8 α-olefin comonomer, or they may have different C3-C8 α-olefin comonomers.

[0134] For example, the ethylene fraction (A-1) can be an ethylene-1-butene copolymer, and the ethylene fraction (A-2) can be an ethylene-1-hexene copolymer.

[0135] Preferably, the two fractions contain the same type of C3-C8 α-olefin comonomer; more preferably, the two fractions are copolymers of ethylene and a comonomer selected from 1-butene, 1-hexene and 1-octene; most preferably, the two fractions are copolymers of ethylene and a comonomer selected from 1-butene and 1-hexene.

[0136] In a preferred embodiment, the two ethylene polymer fractions (A-1 and A-2) are copolymers of ethylene and 1-butene.

[0137] The ethylene copolymer component (B) is also a copolymer of ethylene with one or two C3-C8 α-olefin comonomers, and the ethylene copolymer component (B) contains at least one comonomer that is different from the comonomer of the ethylene copolymer component (A).

[0138] Therefore, the ethylene copolymer component (B) can be a copolymer of ethylene and a C3-C8 α-olefin comonomer, or a terpolymer of ethylene and two C3-C8 α-olefin comonomers.

[0139] Preferably, the ethylene copolymer component (B) is a copolymer of ethylene and a comonomer selected from 1-butene, 1-hexene and 1-octene (more preferably, selected from 1-butene and 1-hexene).

[0140] In a preferred embodiment, the ethylene copolymer component (B) is a copolymer of ethylene and 1-hexene.

[0141] The comonomer content of components (A) and (B) can be measured, or (preferably) in a so-called multi-stage process where one of the components is produced first and then another component is produced in the presence of the first component, 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.

[0142] In addition, the comonomer content of the ethylene polymer fraction (A-2) can be calculated.

[0143] Therefore, the comonomer content of the ethylene polymer fraction (A-2) is calculated according to formula (Ia):

[0144] ,

[0145] In the formula

[0146] x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A).

[0147] cc(A-2) represents the calculated comonomer content of the ethylene polymer fraction (A-2).

[0148] cc(A-1) represents the comonomer content of the ethylene polymer fraction (A-1).

[0149] cc(A) represents the comonomer content of the ethylene copolymer component (A).

[0150] Among them, cc(A-1) and cc(A) are quantified as described in the experimental section. 13 C{ 1 Measured by H NMR.

[0151] The comonomer content of the ethylene copolymer component (B) is calculated according to formula (Ib):

[0152] ,

[0153] In the formula,

[0154] x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P).

[0155] cc(B) represents the calculated comonomer content of the ethylene copolymer component (B).

[0156] cc(A) represents the comonomer content of the ethylene copolymer component (A).

[0157] cc(P) represents the comonomer content of the multimodal polyethylene copolymer (P).

[0158] Among them, cc(A) and cc(P) are quantified as described in the experimental section. 13 C{ 1 Measured by H NMR.

[0159] When only one comonomer (e.g., 1-butene) is present in ethylene copolymer component (A) and the comonomer content of ethylene copolymer component (A) has not been determined, the simplified formula (Ic) can be used to calculate the comonomer content of ethylene copolymer component (A), i.e.:

[0160] ,

[0161] In the formula,

[0162] wA represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal copolymer (P).

[0163] [C4]A represents the calculated 1-butene content of the ethylene copolymer component (A).

[0164] [C4]P represents the 1-butene content of the multimodal polyethylene copolymer (P).

[0165] The same applies if only one comonomer (e.g., 1-hexene) is added during the production of the ethylene copolymer component (B). Here, the simplified formula (Id) can be applied:

[0166] ,

[0167] In the formula,

[0168] wB is the weight fraction of the ethylene copolymer component (B) relative to the multimodal copolymer (P);

[0169] [C6]B represents the calculated 1-hexene content of the ethylene copolymer component (B);

[0170] [C6]P represents the 1-hexene content of the multimodal polyethylene copolymer (P).

[0171] Polyethylene copolymer (P) was quantitatively analyzed as described in the experimental section. 13 C{ 1 The total content of comonomers, as determined by ¹H NMR, is 1.1 to 8.0 mol%, preferably 1.4 to 6.5 mol%, and more preferably 1.8 to 5.0 mol%.

[0172] In the polyethylene copolymer (P) (a terpolymer of ethylene and two different C3-C8 α-olefin comonomers), the content of the first C3-C8 α-olefin comonomer (preferably 1-butene, 1-hexene or 1-octene, more preferably 1-butene or 1-hexene, most preferably 1-butene) is 0.1 to 2.0 mol%, preferably 0.1 to 1.5 mol%, more preferably 0.2 to 1.0 mol%, based on the multimodal polymer (P).

[0173] Based on the multimodal polymer (P), the content of the second C3-C8 α-olefin comonomer (different from the first C3-C8 α-olefin comonomer; preferably 1-butene, 1-hexene or 1-octene, more preferably 1-butene or 1-hexene, most preferably 1-hexene) is 1.0 to 6.0 mol%, preferably 1.3 to 5.0 mol%, more preferably 1.6 to 4.0 mol%.

[0174] Based on the total weight of the ethylene copolymer component (A), the total content of comonomers in the ethylene copolymer component (A) is 0.2 to 3.0 mol%, preferably 0.3 to 2.5 mol%, more preferably 0.4 to 2.0 mol%.

[0175] Based on the total weight of the ethylene polymer fraction (A-1), the comonomer content of the ethylene polymer fraction (A-1) is 0.1 to 2.0 mol%, preferably 0.1 to 1.8 mol%, more preferably 0.2 to 1.6 mol%, and the comonomer content of the ethylene polymer fraction (A-2) is higher than that of the ethylene polymer fraction (A-1).

[0176] The difference in comonomer content between the ethylene polymer fraction (A-2) and the ethylene polymer fraction (A-1) is 0.3 to 3.0 mol%, preferably 0.4 to 2.0 mol%, more preferably 0.5 to 1.5 mol%.

[0177] As described above, the comonomer content of the ethylene polymer fraction (A-2) is calculated according to formula (Ia), and the comonomer content of the ethylene copolymer component (A) is determined by quantitative analysis as described in the experimental section. 13 C{ 1 Measured by H NMR or calculated according to formula (Ic).

[0178] The comonomer content of the ethylene copolymer component (B) can be calculated using formula (Ib) or formula (Id).

[0179] As mentioned above, the comonomer content of ethylene copolymer component (B) is higher than that of ethylene copolymer component (A).

[0180] Therefore, the comonomer content gradually increases from (A-1) to (B), that is, the comonomer content (A-1) < (A-2) < (B).

[0181] The MFR2 (190 °C, 2.16 kg, ISO 1133) of the ethylene copolymer component (A) is 0.2 to 500 g / 10 min, preferably 0.5 to 300 g / 10 min, more preferably 1 to 200 g / 10 min, for example 2 to 100 g / 10 min.

[0182] The MFR2 (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-1) is 0.1 to 100 g / 10 min, preferably 0.2 to 50 g / 10 min, and more preferably 0.3 to 30 g / 10 min.

[0183] The MFR2 (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-2) is higher than that of the ethylene polymer fraction (A-1).

[0184] The MFR2 of the ethylene polymer fraction (A-2) is calculated according to formula (II-a):

[0185]

[0186] In the formula,

[0187] x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A).

[0188] MFR(A-2) is the calculated MFR2 of the ethylene polymer fraction (A-2).

[0189] MFR(A-1) is MFR2 of the ethylene polymer fraction (A-1) (190 °C, 2.16 kg, ISO 1133).

[0190] MFR(A) is MFR2 of ethylene copolymer component (A) (190 °C, 2.16 kg, ISO 1133).

[0191] According to the present invention, the ratio of MFR2 (A-2) (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-2) to MFR2 (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-1), MFR2(A-2) / MFR2(A-1), is 4 to 200, preferably 4 to 150, more preferably 4 to 100, and even more preferably 8 to 50.

[0192] The MFR2 of the ethylene copolymer component (B) is calculated according to formula (II-b):

[0193]

[0194] In the formula,

[0195] x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P).

[0196] MFR(B) is the calculated MFR2 of the ethylene copolymer component (B).

[0197] MFR(P) is MFR2 of multimodal polyethylene copolymer (P) (190 °C, 2.16 kg, ISO 1133).

[0198] MFR(A) is MFR2 of ethylene copolymer component (A) (190 °C, 2.16 kg, ISO 1133).

[0199] In another embodiment of the invention, the MFR of the multimodal polyethylene copolymer (P) 21 The ratio of MFR (190 °C, 21.6 kg, ISO 1133) to MFR2 (190 °C, 2.16 kg, ISO 1133) is MFR 21 / MFR2 is 23 to 60, preferably 24 to 55, more preferably 25 to 50, and even more preferably 28 to 44.

[0200] Even more preferably, the multimodal polymer (P) of the present invention further exhibits multimodality in relation to the density difference between the ethylene copolymer component (A) and the ethylene copolymer component (B). Preferably, the density of the ethylene copolymer component (A) differs from that of the ethylene copolymer component (B), and more preferably, the density of the ethylene copolymer component (A) is higher than that of the ethylene copolymer component (B).

[0201] The density (ISO 1183) of the ethylene copolymer component (A) is 930 to 950 kg / m³. 3 Preferred weight is 932 to 948 kg / m³. 3 More preferably 934 to 946 kg / m 3 .

[0202] The density of the ethylene copolymer component (B) is calculated according to formula (III):

[0203] ,

[0204] In the formula,

[0205] x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P).

[0206] Density (B) is the calculated density of the ethylene copolymer component (B).

[0207] Density (A) is the density of the ethylene copolymer component (A) (ISO 1183).

[0208] Density (P) is the density of the multimodal polyethylene copolymer (P) (ISO 1183).

[0209] The densities (ISO 1183) of polymer fractions (A-1) and (A-2) are 930 to 950 kg / m³. 3 Preferred weight is 932 to 948 kg / m³. 3 More preferably 934 to 946 kg / m 3 .

[0210] The densities of polymer fraction (A-1) and fraction (A-2) can be the same or different from each other.

[0211] The density of the ethylene polymer fraction (A-2) is calculated according to formula (IV):

[0212] ,

[0213] In the formula,

[0214] x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A).

[0215] Density (A-2) is the calculated density of the ethylene polymer fraction (A-2).

[0216] Density (A) is the density of the ethylene copolymer component (A) (ISO 1183).

[0217] Density (A-1) is the density of the ethylene polymer fraction (A-1) (ISO 1183).

[0218] The preferred metallocene-catalyzed multimodal copolymer (P) is linear low-density polyethylene (LLDPE), the meaning of which is well known.

[0219] More preferably, the multimodal copolymer (P) is multimodal (i.e., has differences) at least in terms of MFR2 and comonomer content, and in terms of the densities of ethylene copolymer component (A) and ethylene copolymer component (B) (i.e., has differences), as defined above, below or in the claims (including any preferred range or embodiment of the polymer composition).

[0220] Metallocene-catalyzed multimodal copolymers (P) can be produced via a three-stage process, preferably comprising a first slurry reactor (loop reactor 1), wherein the first slurry loop reactor is connected in series with another slurry reactor (loop reactor 2), such that a first ethylene polymer fraction (A-1) produced in loop reactor 1 is fed to loop reactor 2, where a second ethylene polymer fraction (A-2) is generated in the presence of the first fraction (A-1). Loop reactor 2 is then connected in series with a gas-phase reactor (GPR), such that the first ethylene copolymer 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 selected such that the products produced in the two slurry reactors differ in terms of melt flow rate (MFR) and comonomer content.

[0221] For example, such processes are described in WO 2016198273, WO 2021009189, WO 2021009190, WO 2021009191, and WO2021009192. These references provide complete details on how to prepare suitable metallocene-catalyzed multimodal copolymers (P).

[0222] The appropriate process is the Borstar PE process or the Borstar PE 3G process.

[0223] Therefore, according to the present invention, the metallocene-catalyzed multimodal copolymer (P) is preferably produced in a loop-loop-gas phase tandem reactor. A prepolymerization step may be performed prior to such polymerization. The purpose of prepolymerization is to polymerize a small amount of polymer to the catalyst at low temperature and / or low monomer concentration. Prepolymerization can improve the performance of the catalyst in the slurry and / or modify the properties of the final polymer. The prepolymerization step is preferably carried out in the slurry, and the amount of polymer produced in the optional prepolymerization step is included in the amount (wt%) of the ethylene copolymer component (A) or the amount (wt%) of the ethylene polymer fraction (A-1).

[0224] Preferably, in the presence of a prepolymerization step, all catalyst components are added during the prepolymerization step. However, where the solid catalyst components and cocatalyst can be fed separately, only a portion of the cocatalyst can be added to the prepolymerization stage, with the remainder added to subsequent polymerization stages. In such cases, a sufficient amount of cocatalyst also needs to be added to the prepolymerization stage to ensure adequate polymerization.

[0225] It should be understood that, within the scope of this invention, the amount of polymer produced in the prepolymerization step accounts for 1 to 5 wt% of the final metallocene-catalyzed multimodal copolymer (P). This can be counted as a portion of the first ethylene polymer component (A) and the amount (wt%) of the corresponding ethylene polymer fraction (A-1).

[0226] catalyst

[0227] The metallocene-catalyzed multimodal copolymer (P) used in the method of this invention is a multimodal copolymer (P) prepared using a metallocene catalyst. The metallocene catalyst comprises a metallocene complex and a cocatalyst. In this document, the metallocene compound or complex is also referred to as an organometallic compound (C).

[0228] Organometallic compounds (C) contain transition metals (M) from Groups 3 to 10 of the periodic table (IUPAC 2007), or actinide or lanthanide transition metals (M).

[0229] According to the present invention, the term "organometallic compound (C)" includes any metallocene or non-metallocene compound containing a transition metal, which contains at least one organic (coordinating) ligand and exhibits catalytic activity alone or in conjunction with a co-catalyst. Transition metal compounds are well known in the art, and the present invention covers compounds of metals from Groups 3 to 10 of the Periodic Table (IUPAC 2007) (e.g., Groups 3 to 7, or Groups 3 to 6, e.g., Groups 4 to 6), as well as compounds of lanthanides or actinides.

[0230] In one embodiment, the organometallic compound (C) has the following formula (Y):

[0231] (Y)

[0232] In the formula,

[0233] Each X is independently a halogen atom, C 1-6 Alkyl, C 1-6 Alkoxy, phenyl, or benzyl;

[0234] Each Het is independently a monocyclic heteroaryl group containing at least one heteroatom selected from O or S;

[0235] L is -R'2Si-, and each R' is independently C. 1-20 Hydrocarbon group or C 1-10 alkoxy-substituted C 1-10 alkyl;

[0236] M is Ti, Zr, or Hf;

[0237] Each R 1 Same or different, and for C 1-6 Alkyl or C 1-6 Alkoxy;

[0238] Each n is between 1 and 2;

[0239] Each R 2Same or different, and for C 1-6 Alkyl, C 1-6 Alkoxy or -Si(R)3 group;

[0240] Each R can be optionally divided by 1 to 3 Cs. 1-6 Alkyl-substituted C 1-10 Alkyl or phenyl;

[0241] Each p is between 0 and 1.

[0242] Preferably, the compound of formula (Y) has the following structure:

[0243] (Y´)

[0244] In the formula,

[0245] Each X is independently a halogen atom, C 1-6 Alkyl, C 1-6 Alkoxy, phenyl, or benzyl;

[0246] L is Me2Si-;

[0247] Each R 1 Same or different, and for C 1-6 Alkyl groups, such as methyl or tert-butyl;

[0248] Each n is between 1 and 2;

[0249] R 2 It is a -Si(R)3 alkyl group; each p is 1;

[0250] Each R is C 1-6 Alkyl or phenyl.

[0251] The highly preferred complex of formula (Y) is as follows:

[0252]

[0253]

[0254] Most preferably, the complex dimethylsilanediylbis[2-(5-trimethylsilylfuran-2-yl)-4,5-dimethylcyclopentadien-1-yl]zirconium dichloride is used.

[0255] More preferably, the ethylene polymer component (A) and component (B) of the multimodal copolymer (P) are prepared using the same metallocene catalyst (i.e., in the presence of the same metallocene catalyst).

[0256] As is well known in the art, a co-catalyst (also known as an activator) is required to form the catalyst. Co-catalysts containing Al or B are well known in the art and can be used here. Aluminoxanes (e.g., MAO) or boron-based co-catalysts (e.g., borates) are preferred.

[0257] Metallocene-catalyzed multimodal copolymers (P) may contain optional additives and / or fillers.

[0258] Optional additives and fillers, and their amounts, are common in membrane applications. Examples of such additives include, but are not limited to, antioxidants, UV stabilizers, pigments, fillers, antistatic agents, antiblocking agents, nucleating agents, and acid scavengers.

[0259] In one embodiment of the invention, the metallocene-catalyzed multimodal copolymer (P) contains no processing aids, especially no fluorine-based polymer processing aids.

[0260] It should be understood that any additives and / or fillers described herein may optionally be added in the form of a so-called masterbatch (containing the corresponding additives and a carrier polymer). In this case, the carrier polymer is not accounted for in the polymer component of the metallocene-catalyzed multimodal copolymer (P), but rather in the amount of the corresponding additive, based on the total amount of the polymer composition (100 wt%).

[0261] The membrane of the present invention

[0262] The membrane of the present invention comprises at least one layer comprising a metallocene-catalyzed multimodal copolymer (P). The membrane can be a monolayer membrane comprising a metallocene-catalyzed multimodal copolymer (P) or a multilayer membrane, wherein at least one layer comprises a metallocene-catalyzed multimodal copolymer (P). The terms "monolayer membrane" and "multilayer membrane" have their common meanings in the art.

[0263] The single-layer or multilayer membranes of the present invention may consist of the metallocene-catalyzed multimodal copolymer (P) itself, or a blend of the metallocene-catalyzed multimodal copolymer (P) with other polymers. In the case of blends, any other polymer is different from the metallocene-catalyzed multimodal copolymer (P), and is preferably a polyolefin. A portion of the above-mentioned additives may be optionally added to the metallocene-catalyzed multimodal copolymer (P) during membrane preparation.

[0264] Preferably, at least one layer of the present invention comprises at least 50 wt%, more preferably at least 60 wt%, even more preferably at least 70 wt%, even more preferably at least 80 wt% of the metallocene-catalyzed multimodal copolymer (P) of the present invention. Most preferably, the at least one layer of the membrane of the present invention is composed of a metallocene-catalyzed multimodal copolymer (P).

[0265] Therefore, the membrane of the present invention may comprise a single layer (i.e., a monolayer membrane) or may be a multilayer structure. Multilayer membranes typically and preferably comprise at least three layers.

[0266] These films are 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 film or a cast film, especially a blown film. For example, blown films are produced as follows: extruded through an annular die, blown into a tubular film by forming a film bubble, which is then flattened between clamping rollers after curing. The film can then be slit, cut, or processed (e.g., folded) as needed. Conventional film production techniques can be used in this regard. If the preferred blown film or cast film is a multilayer film, the layers are typically co-extruded. Those skilled in the art understand suitable extrusion conditions.

[0267] The film according to the invention can undergo post-processing, such as surface modification, lamination, or orientation processes. This orientation process can be uniaxial orientation (MDO) or biaxial orientation, with uniaxial orientation being preferred.

[0268] In another preferred embodiment, the film is unoriented.

[0269] The resulting membrane can have any thickness conventional in the art. The membrane thickness is not critical, but depends on the end-use. Therefore, the membrane thickness can be, for example, less than 300 μm, typically 6 to 200 μm, preferably 10 to 180 μm, such as 20 to 150 μm or 20 to 120 μm. If desired, the polymers of the present invention can achieve thicknesses of less than 100 μm, for example, less than 50 μm. Membranes of the present invention with thicknesses even less than 20 μm can also be produced while maintaining good mechanical properties.

[0270] Furthermore, the present invention also relates to the use of the articles of the invention as packaging materials, particularly as packaging materials for food and / or medical products.

[0271] The specific design of the metallocene-catalyzed multimodal copolymer (P) of this invention makes the polymer ideally suited for membrane preparation. Benefits include the required low melt pressure, which promises to increase yields in blown film processes, along with low seal initiation temperatures and high impact strength.

[0272] As described in the experimental section, the seal initiation temperature (SIT) measured using a 40 µm test blown film made of multimodal polyethylene copolymer (P) conforms to inequality (X):

[0273]

[0274] In the formula, MFR2HMW is the MFR2 of the ethylene copolymer component (B) (190 °C, 2.16 kg, ISO 1133), calculated according to formula (II-b).

[0275] As an alternative or supplement, the membrane of the present invention is characterized in that the dart impact strength (DDI) measured with a 40 μm monolayer test blown film according to ISO 7765-1:1988 / Method A is at least 1100g and at most 2500g, preferably 1300g to 2300g, and more preferably 1500g to 2200g.

[0276] The present invention will be further described below with reference to non-limiting embodiments.

[0277] Measurement method:

[0278] Unless otherwise stated in the description or experimental section, the determination of polymer properties (including its fractions and components) and / or any sample preparation shall be performed using the methods described in the text or experimental section.

[0279] melt flow rate

[0280] Melt flow rate (MFR) is determined according to ISO 1133, with units of g / 10 min. MFR is an indicator of the flowability and, consequently, processability of a polymer. A higher melt flow rate generally indicates a lower polymer viscosity. For polyethylene, MFR is measured at 190 °C. MFR can be measured under various loads, such as 2.16 kg (MFR2), 5 kg (MFR5), or 21.6 kg (MFR6). 21 ).

[0281] MFR of component B and fraction (A-2) 2 calculate

[0282] The MFR2 of the ethylene polymer fraction (A-2) is calculated according to formula (II-a):

[0283]

[0284] In the formula,

[0285] x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A).

[0286] MFR(A-2) is the calculated MFR2 of the ethylene polymer fraction (A-2).

[0287] MFR(A-1) is MFR2 of the ethylene polymer fraction (A-1) (190 °C, 2.16 kg, ISO 1133).

[0288] MFR(A) is MFR2 of ethylene copolymer component (A) (190 °C, 2.16 kg, ISO 1133).

[0289] For the ethylene copolymer component (B), MFR2 is calculated according to formula (II-b):

[0290]

[0291] In the formula,

[0292] x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P).

[0293] MFR(B) is the calculated MFR2 of the ethylene copolymer component (B).

[0294] MFR(P) is MFR2 of multimodal polyethylene copolymer (P) (190 °C, 2.16 kg, ISO 1133).

[0295] MFR(A) is MFR2 of ethylene copolymer component (A) (190 °C, 2.16 kg, ISO 1133).

[0296] density

[0297] The density of the polymer was measured according to ISO 1183-1 using compression-molded specimens prepared in accordance with EN ISO 1872-2, and the unit was kg / m³. 3 .

[0298] The density of the ethylene copolymer component (B) is calculated according to formula (III):

[0299] ,

[0300] In the formula,

[0301] x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P).

[0302] Density (B) is the calculated density of the ethylene copolymer component (B).

[0303] Density (A) is the density of the ethylene copolymer component (A) (ISO 1183).

[0304] Density (P) is the density of the multimodal polyethylene copolymer (P) (ISO 1183).

[0305] The density of the ethylene polymer fraction (A-2) is calculated according to formula (IV):

[0306] ,

[0307] In the formula,

[0308] x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A).

[0309] Density (A-2) is the calculated density of the ethylene polymer fraction (A-2).

[0310] Density (A) is the density of the ethylene copolymer component (A) (ISO 1183).

[0311] Density (A-1) is the density of the ethylene fraction (A-1) (ISO 1183).

[0312] Comonomer content:

[0313] Quantitative analysis of microstructure using NMR spectroscopy

[0314] The quantitative nuclear magnetic resonance (NMR) spectroscopy method described in European patent EP4108435A1 is used to quantify the comonomer content of polymers.

[0315] The comonomer content of the ethylene polymer fraction (A-2) is calculated according to formula (Ia):

[0316] ,

[0317] In the formula

[0318] x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A).

[0319] cc(A-2) represents the calculated comonomer content of the ethylene polymer fraction (A-2).

[0320] cc(A-1) represents the comonomer content of the ethylene polymer fraction (A-1).

[0321] cc(A) represents the comonomer content of the ethylene copolymer component (A).

[0322] cc(A-1) and cc(A) are quantified as described above. 13 C{ 1 Measured by H NMR.

[0323] The comonomer content of the ethylene copolymer component (B) is calculated according to formula (Ib):

[0324] ,

[0325] In the formula,

[0326] x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P).

[0327] cc(B) represents the calculated comonomer content of the ethylene copolymer component (B).

[0328] cc(A) represents the comonomer content of the ethylene copolymer component (A).

[0329] cc(P) represents the comonomer content of the multimodal polyethylene copolymer (P).

[0330] Wherein, cc(A) and cc(P) are quantified as described above. 13 C{ 1 H NMR determination.

[0331] When only one comonomer (e.g., 1-butene) is present in the ethylene copolymer component (A) and the comonomer content of the ethylene copolymer component (A) has not been determined, the simplified formula (Ic) can be used to calculate the comonomer content of the ethylene copolymer component (A), namely:

[0332] ,

[0333] In the formula,

[0334] wA represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal copolymer (P).

[0335] [C4]A represents the calculated 1-butene content of the ethylene copolymer component (A).

[0336] [C4]P represents the 1-butene content of the multimodal polyethylene copolymer (P).

[0337] If only one comonomer (e.g., 1-hexene) is added during the production of ethylene copolymer component (B), the simplified formula (Id) can be applied:

[0338] ,

[0339] In the formula,

[0340] wB is the weight fraction of the ethylene copolymer component (B) relative to the multimodal copolymer (P);

[0341] [C6]B represents the calculated 1-hexene content of the ethylene copolymer component (B);

[0342] [C6]P represents the 1-hexene content of the multimodal polyethylene copolymer (P).

[0343] Molecular weight, molecular weight distribution (Mn, Mw, MWD):

[0344] According to ASTM D6474-12, the molecular weight average (Mz, Mw, and Mn), molecular weight distribution (MWD), and its width (expressed as polydispersity index PDI = Mw / Mn, where Mn is the number-average molecular weight and Mw is the weight-average molecular weight) are determined by gel permeation chromatography (GPC) using the following formula:

[0345]

[0346] For a constant elution volume interval ΔV i , where A i and M i These are respectively related to the elution volume V i The relevant peak slice area and polyolefin molecular weight (MW) are used, where N equals the number of data points obtained from the chromatogram between the integration limits.

[0347] High-temperature GPC instruments were used, equipped with infrared (IR) detectors (Polymer Char IR4 or IR5 from Valencia, Spain) or differential refractometers (RI) from Agilent Technologies, with 3×Agilent-PLgel Olexis columns and 1×Agilent-PLgel Olexis Guard columns. The solvent and mobile phase used were 1,2,4-trichlorobenzene (TCB) stabilized with 250 mg / L 2,6-di-tert-butyl-4-methylphenol. The chromatographic system was run at a constant flow rate of 1 mL / min at 160 °C. 200 μL of sample solution was injected for each analysis. Data acquisition was performed using Agilent Cirrus software version 3.3 or Polymer Char GPC-IR control software.

[0348] The chromatographic column set was calibrated using a universal calibration method with 19 polystyrene (PS) standards ranging from 0.5 kg / mol to 11500 kg / mol with narrow MWD. ​​The PS standards were dissolved at room temperature for several hours. The conversion of the polystyrene peak molecular weight to the polyolefin molecular weight was achieved using the Mark-Houwink equation and the following Mark-Houwink constant:

[0349]

[0350] The calibration data were fitted using a third-order polynomial.

[0351] All samples were prepared at concentrations ranging from 0.5 to 1 mg / mL and dissolved by gentle shaking at 160 °C for 3 hours (for PE).

[0352] Analytical temperature-elution fractionation (ATREF)

[0353] Chemical composition distribution was determined using an analytical temperature-elution fractionation method (see: Soares, JBP, Fractionation, in Encyclopedia of Polymer Science and Technology, John Wiley & Sons, New York, Vol. 10, pp. 75-131, 2001). Polymer separation in TREF was based on their crystallinity in solution. TREF spectra were generated using a CRYSTAF-TREF 200+ instrument manufactured by Polymer Char SA (Valencia, Spain).

[0354] The polymer sample was dissolved in 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L 2,6-di-tert-butyl-4-methylphenol) at a concentration of 1.5 to 2.0 mg / mL and incubated at 150 °C for 180 min. 1.8 mL of the sample solution was injected into a column (8 mm inner diameter, 15 cm length, packed with an inert support, such as glass beads). The column was then rapidly cooled to 110 °C and held at 110 °C for 30 min to achieve stability, followed by slow cooling to 35 °C at a constant cooling rate (0.1 °C / min). Subsequently, the polymer was eluted with 1,2,4-trichlorobenzene (stabilized with 250 mg / L 2,6-di-tert-butyl-4-methylphenol) at 35 °C for 10 min at a flow rate of 0.5 mL / min. The temperature was then increased from 35 °C to 135 °C at a constant ramp rate of 0.5 °C / min and a flow rate of 0.5 mL / min. The polymer concentration during elution was recorded by an infrared detector (measuring CH absorption at a wavelength of 3.5 μm). The detector response was plotted as a function of temperature. The normalized concentration curves are presented as a tiered graph, simultaneously displaying the cumulative concentration signal (normalized to 100).

[0355] Low crystallinity fraction (LCF), medium crystallinity fraction (MCF), and high crystallinity fraction (HCF) are defined as the weight fractions eluted at temperatures >35°C to 70°C (for LCF), >70°C to 90°C (for MCF), and >90°C to 105°C (for HCF), respectively, and can be calculated using the following formula:

[0356]

[0357] Dart Impact Strength (DDI): Impact resistance determined by the free-fall dart method.

[0358] DDI measurements were performed on the membranes produced as shown below, according to ISO 7765-1:1988 / Method A. This test method specifies the energy value that causes the membrane to fail under specified conditions of impact from a freely falling dart at a specific height, an energy value that would cause 50% of the test specimens to fail (Step Method A). A uniform increment of dart mass was used during the test, and after each specimen was tested, the dart weight was decreased or increased in a uniform increment based on the observed result of the specimen (failure or rupture).

[0359] Standard conditions:

[0360] Adjustment time: >96 hours

[0361] Test temperature: 23℃

[0362] Darthead material: phenolic resin

[0363] Dart diameter: 38 mm

[0364] Drop height: 660 mm

[0365] result:

[0366] Impact fracture weight -50% [g]

[0367] Sealing start temperature (SIT); Sealing end temperature (SET); Sealing range:

[0368] This method is used to determine the sealing temperature range (sealing range) of polyethylene films (particularly blown or cast films). The sealing temperature range is the temperature range under which the film can be sealed under the following given conditions.

[0369] The lower limit (heat seal initiation temperature (SIT)) is the sealing temperature at which a 5N seal strength is achieved. The upper limit (seal termination temperature (SET)) is the temperature at which the membrane adheres to the sealing device.

[0370] Measurements were performed according to a slightly modified version of ASTM F1921-12. Unlike ASTM F1921-12, the test parameters for sealing pressure, sealing time, delay time, and clamp separation rate were modified. The force / temperature profile was measured until thermal rupture of the membrane occurred. In addition to the rupture mode assessment described in the standard, other rupture modes were used.

[0371] The sealing range was measured on a J&B Universal Sealing Machine Type 4000, using a blown film thickness of 40 µm. Other parameters are as follows:

[0372] Adjustment time: >96 hours

[0373] Sample width: 25 mm

[0374] Sealing pressure: 0.4 N / mm 2 (PE)

[0375] Sealing time: 1 second

[0376] Delay time: 30 seconds

[0377] Sealing clamp size: 50×5 mm

[0378] Sealing clamp shape: flat

[0379] Sealing clamp coating: Niptef

[0380] Sealing temperature: ambient temperature -240℃

[0381] Sealing temperature interval: 5℃

[0382] Starting temperature: 50℃

[0383] Fixture separation rate: 42 mm / s

[0384] Membrane sample preparation

[0385] A single-layer test membrane with a thickness of 40 µm was prepared using a W&H semi-commercial production line, consisting of the inventive multimodal copolymer (P) and a corresponding comparative polymer. The membrane samples were produced using BUR 1:2.5. The melt temperature was approximately 235–245 °C, the frosting distance was 600 mm, the screw speed was 108–122 rpm, and the winding speed was approximately 22 m / min.

[0386] Experimental Section

[0387] Catalysis Example: Catalyst Preparation (CAT1)

[0388] SiO 2 Loading:

[0389] 10 kg of silica (PQ Corporation ES757, calcined at 600 °C) was added to the reactor from the feed tank and inertized in the reactor until the O2 level was below 2 ppm.

[0390] Preparation of MAO / Toluene / MC:

[0391] 14.1 kg of a 30 wt% MAO toluene solution was weighed from a balance and added to another reactor. Then, 4.0 kg of toluene was added at 25 °C (oil bath temperature), and the mixture was stirred at 95 rpm. After the addition of toluene, the stirring speed was increased from 95 rpm to 200 rpm for 30 minutes. 477 g of metallocene (MC) racemic dimethylsilanediylbis{2-(5-(trimethylsilyl)furan-2-yl)-4,5-dimethylcyclopentadien-1-yl}zirconium dichloride was added from a metal container, followed by rinsing with 4 kg of toluene (total toluene 8.0 kg). The reactor stirring speed was adjusted to 95 rpm upon the addition of MC, then restored to 200 rpm for a 3-hour reaction time. After the reaction was complete, the MAO / toluene / MC solution was transferred to a feed container.

[0392] Catalyst preparation:

[0393] The reactor temperature was set to 10 °C (oil circulation temperature), and the stirring speed was set to 40 rpm for adding the MAO / toluene / MC solution. 22.2 kg of the MAO / toluene / MC solution was added over 205 minutes, followed by stirring for 60 minutes (oil circulation temperature set to 25 °C). After stirring, the "dry mixture" was stabilized at 25 °C (oil circulation temperature) for 12 hours, with the stirring speed set to 0 rpm. The reactor temperature was then adjusted to 20 °C (reciprocating), and the stirring was started and operated at 5 rpm, repeating several times per hour.

[0394] After stabilization, the catalyst was dried at 60 °C (oil circulation temperature) under a nitrogen flow of 2 kg / h for 2 hours, and then dried under vacuum for 13 hours (with the same nitrogen flow and a stirring speed of 5 rpm). Samples of the dried catalyst were taken, and the HC content was measured using a Sartorius MA45 moisture analyzer in a glove box via thermogravimetric analysis. The target HC level was <2% (actual 1.3%).

[0395] Polymerization: Invention Examples: The multimodal polyethylene copolymers (P) (IE1 to IE4) and comparative examples (CE1 and CE2) of the present invention

[0396] The Borstar pilot plant uses a three-reactor configuration (loop 1-loop 2-GPR1) and a prepolymer loop reactor.

[0397] The multimodal copolymers (P) of Examples IE1 to IE4 and Comparative Examples CE1 and CE2 were prepared using the polymerization conditions shown in Table 1.

[0398] Table 1: Aggregation Conditions

[0399] N / A not analyzed

[0400] Calculated according to the formula [C4]A = [C4]P / wA;

[0401] Calculated according to the formula [C6]B = [C6]P / wB.

[0402] The polymers of IE1 to IE4, as well as CE1 and CE2, were mixed with only 2000 ppm of Irganox 1010 FF and 500 ppm of Irgafos 168 FF (without PPA), and compounded and extruded under a nitrogen atmosphere using a ZSK57 twin-screw extruder to obtain granules; the melt temperature was approximately 230 to 235 °C.

[0403] Table 2: Material properties and membrane parameters of the multimodal copolymer (P) of the invention example and the comparative copolymer.

[0404]

[0405] From Table 2 above (and Figure 2 As can be seen, the ATREF spectrum of the invention example has specific characteristics due to the three-peak distribution (achieved by producing materials with different MFRs in two loop reactors), which is different from the comparative example, although the final MFR, density (finally, and component (A) and component (B)) and GPR split are similar in all embodiments.

[0406] This trimodal distribution of the invention results in a lower SIT value. Compared to a comparative example with similar MFR2HMW and final density, as well as similar densities of components (A) and (B), the SIT of the invention is reduced by approximately 2-3 °C. See [link to relevant documentation]. Figure 1 and the table above.

[0407] Meanwhile, it can be seen that the excellent impact resistance of the resulting membrane and the melt pressure required to produce such membranes were not affected.

Claims

1. A metallocene-catalyzed multimodal polyethylene copolymer (P), wherein the multimodal polyethylene copolymer (P) is a terpolymer of ethylene and two different C3-C8 α-olefin comonomers, and the multimodal polyethylene copolymer (P) has the following characteristics: Density (ISO 1183) is 910 to 925 kg / m³ 3 ; MFR2 (190 °C, 2.16 kg, ISO 1133) is 0.3 to 1.5 g / 10 min; and The multimodal polyethylene copolymer (P) is further characterized in that the ATREF spectrum measured as described in the experimental section shows a three-peak chemical composition distribution (CCD), and the multimodal polyethylene copolymer (P) is composed of the following: a) 35.0 wt% to 50.0 wt% of a low crystallinity fraction (LCF) based on multimodal polyethylene copolymer (P), said low crystallinity fraction (LCF) eluted between >35 and 70 °C; b) 20.0 wt% to 37.0 wt% of a medium crystalline fraction (MCF) based on multimodal polyethylene copolymer (P), said medium crystalline fraction (MCF) eluted between >70 and 90 °C; c) 3.0 wt% to 30.0 wt% of a highly crystalline fraction (HCF) based on multimodal polyethylene copolymer (P), said highly crystalline fraction (HCF) eluted between >90 and 105 °C; d) The total amount of low crystallinity fraction (LCF), medium crystallinity fraction (MCF), and high crystallinity fraction (HCF) is at least 95.0 wt%; e) The remaining portion of the multimodal polyethylene copolymer (P) is eluted at a temperature ≤35 °C; and The ratio of medium-crystallization fraction to high-crystallization fraction (MCF / HCF) is 0.6 to 3.

0.

2. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to claim 1, wherein, The multimodal polyethylene copolymer (P) is a terpolymer of ethylene and two different C3-C8 α-olefin comonomers, and the density (ISO 1183) of the multimodal polyethylene copolymer (P) is 910 to 925 kg / m³. 3 MFR2 (190 °C, 2.16 kg, ISO 1133) was 0.3 to 1.5 g / 10 min, determined quantitatively as described in the experimental section. 13 C{ 1 The total comonomer content, as determined by ¹H NMR, is between 1.1 and 8.0 mol%, and the multimodal polyethylene copolymer (P) is composed of an in-situ blend of the following components: (i) an ethylene copolymer component (A), said ethylene copolymer component (A) being composed of an ethylene polymer fraction (A-1) and an ethylene polymer fraction (A-2); and (ii) Ethylene copolymer component (B); Wherein, the ethylene copolymer component (A) is a copolymer of ethylene and one or two C3-C8 α-olefin comonomers, and the total content of the comonomers in the ethylene copolymer component (A) is 0.2 to 3.0 mol%, based on the total weight of the ethylene copolymer component (A). Based on the total weight of the ethylene polymer fraction (A-1), the ethylene polymer fraction (A-1) was quantitatively analyzed as described in the experimental section. 13 C{ 1 The comonomer content measured by ¹H NMR ranged from 0.1 to 2.0 mol%. The comonomer content of the ethylene polymer fraction (A-2) was higher than that of the ethylene polymer fraction (A-1), and the difference in comonomer content between the two fractions ranged from 0.3 to 3.0 mol%. The comonomer content of the ethylene polymer fraction (A-2) is calculated according to formula (Ia): ， In the formula x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A). cc(A-2) represents the calculated comonomer content of the ethylene polymer fraction (A-2). cc(A-1) represents the comonomer content of the ethylene polymer fraction (A-1). cc(A) represents the comonomer content of the ethylene copolymer component (A). Among them, cc(A-1) and cc(A) are quantified as described in the experimental section. 13 C{ 1 Measured by H NMR; Ethylene copolymer component (B) is a copolymer of ethylene and one or two C3-C8 α-olefin comonomers. Ethylene copolymer component (B) contains at least one comonomer different from the comonomer of ethylene copolymer component (A). The comonomer content of ethylene copolymer component (B) is higher than that of ethylene copolymer component (A). The comonomer content of ethylene copolymer component (B) is calculated according to formula (Ib): ， In the formula, x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P). cc(B) represents the calculated comonomer content of the ethylene copolymer component (B). cc(A) represents the comonomer content of the ethylene copolymer component (A). cc(P) represents the comonomer content of the multimodal polyethylene copolymer (P). Among them, cc(A) and cc(P) are quantified as described in the experimental section. 13 C{ 1 Measured by H NMR.

3. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to any one of the preceding claims, wherein, The multimodal polyethylene copolymer (P) is a terpolymer of ethylene and two different C3-C8 α-olefin comonomers; The first C3-C8 α-olefin comonomer of the multimodal polyethylene copolymer (P) is preferably 1-butene, 1-hexene, or 1-octene, more preferably 1-butene or 1-hexene, and most preferably 1-butene; based on the multimodal polyethylene copolymer (P), the total amount of the first C3-C8 α-olefin comonomer is 0.1 to 2.0 mol%, preferably 0.1 to 1.5 mol%, more preferably 0.2 to 1.0 mol%; and The second C3-C8 α-olefin comonomer of the multimodal polyethylene copolymer (P) is different from the first C3-C8 α-olefin comonomer. The second C3-C8 α-olefin comonomer is preferably 1-butene, 1-hexene, or 1-octene, more preferably 1-butene or 1-hexene, and most preferably 1-hexene. Based on the multimodal polyethylene copolymer (P), the amount of the second C3-C8 α-olefin comonomer is 1.0 to 6.0 mol%, preferably 1.3 to 5.0 mol%, and more preferably 1.6 to 4.0 mol%.

4. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to any one of the preceding claims, wherein, The multimodal polyethylene copolymer (P) is a terpolymer of ethylene and two C3-C8 α-olefin comonomers, and the density (ISO 1183) of the multimodal polyethylene copolymer (P) is 910 to 925 kg / m³. 3 The MFR2 (190 °C, 2.16 kg, ISO 1133) is 0.3 to 1.5 g / 10 min, and the multimodal polyethylene copolymer (P) consists of an in-situ blend of the following components: (i) an ethylene copolymer component (A), said ethylene copolymer component (A) being composed of an ethylene polymer fraction (A-1) and an ethylene polymer fraction (A-2); and (ii) Ethylene copolymer component (B); The density (ISO 1183) of the ethylene copolymer component (A) is 930 to 950 kg / m³. 3 MFR2 (190 °C, 2.16 kg, ISO 1133) is 0.2 to 500 g / 10 min; The densities (ISO 1183) of fractions (A-1) and (A-2) are 930 to 950 kg / m³. 3 ; The MFR2 (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-1) is 0.1 to 100 g / 10 min; The MFR2 (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-2) is higher than that of the ethylene polymer fraction (A-1); The ratio of MFR2 (190 °C, 2.16 kg, ISO 1133) of ethylene polymer fraction (A-2) to MFR2 (190 °C, 2.16 kg, ISO 1133) of ethylene polymer fraction (A-1) is 4 to 200. The MFR2 of the ethylene polymer fraction (A-2) is calculated according to formula (II-a): ， In the formula, x represents the weight fraction of the ethylene polymer fraction (A-1) relative to the ethylene copolymer component (A). MFR(A-2) is the calculated MFR2 of the ethylene polymer fraction (A-2). MFR(A-1) is MFR2 of the ethylene polymer fraction (A-1) (190 °C, 2.16 kg, ISO 1133). MFR(A) is MFR2 of ethylene copolymer component (A) (190 °C, 2.16 kg, ISO 1133). The density and MFR2 of the ethylene copolymer component (B) are lower than those of the ethylene copolymer component (A). MFR2 is calculated according to formula (II-b): ， In the formula, x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P). MFR(B) is the calculated MFR2 of the ethylene copolymer component (B). MFR(P) is MFR2 of multimodal polyethylene copolymer (P) (190 °C, 2.16 kg, ISO 1133). MFR(A) is MFR2 of ethylene copolymer component (A) (190 °C, 2.16 kg, ISO 1133). Density is calculated according to formula (III): ， In the formula, x represents the weight fraction of the ethylene copolymer component (B) relative to the multimodal polyethylene copolymer (P). Density (B) is the calculated density of the ethylene copolymer component (B). Density (A) is the density of the ethylene copolymer component (A) (ISO 1183). Density (P) is the density of the multimodal polyethylene copolymer (P) (ISO 1183).

5. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to any one of claims 2 to 4, wherein, The ethylene copolymer component (A) is a copolymer of ethylene and one C3-C8 α-olefin comonomer, or a terpolymer of ethylene and two C3-C8 α-olefin comonomers. Ethylene polymer fractions (A-1) and (A-2) may have the same type of C3-C8 α-olefin comonomer or may have different C3-C8 α-olefin comonomers. Preferably, ethylene polymer fractions (A-1) and (A-2) have the same type of C3-C8 α-olefin comonomer. The ethylene copolymer component (B) is a copolymer of ethylene and a C3-C8 α-olefin comonomer, or a terpolymer of ethylene and two C3-C8 α-olefin comonomers. At least one comonomer of the ethylene copolymer component (B) is different from the comonomer of the ethylene copolymer component (A). Preferably, the ethylene copolymer component (B) is a copolymer of ethylene and a comonomer selected from 1-butene, 1-hexene and 1-octene. More preferably, the ethylene copolymer component (B) is a copolymer of ethylene and a comonomer selected from 1-butene and 1-hexene.

6. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to claim 5, wherein, The ethylene copolymer component (A) is a copolymer of ethylene and 1-butene; The ethylene polymer fraction (A-1) and ethylene polymer fraction (A-2) are copolymers of ethylene and 1-butene; The ethylene copolymer component (B) is a copolymer of ethylene and 1-hexene.

7. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to any one of the preceding claims, wherein, The MFR of the multimodal polyethylene copolymer (P) 21 The ratio of MFR (190 °C, 21.6 kg, ISO 1133) to MFR2 (190 °C, 2.16 kg, ISO 1133) is MFR 21 / MFR2 is 23 to 60, preferably 24 to 55, more preferably 25 to 50, and even more preferably 28 to 44.

8. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to any one of claims 2 to 7, wherein, The ratio of MFR2 (A-2) (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-2) to MFR2 (190 °C, 2.16 kg, ISO 1133) of the ethylene polymer fraction (A-1), MFR2(A-2) / MFR2(A-1), is 4 to 150, preferably 4 to 100, and more preferably 8 to 50.

9. The metallocene-catalyzed multimodal polyethylene copolymer (P) according to any one of the preceding claims, wherein, The multimodal polyethylene copolymer (P) is prepared in the presence of a metallocene complex of formula (Y): (Y) In the formula, Each X is independently a halogen atom, C 1-6 Alkyl, C 1-6 Alkoxy, phenyl, or benzyl; Each Het is independently a monocyclic heteroaryl group containing at least one heteroatom selected from O or S; L is -R'2Si-, and each R' is independently C. 1-20 Hydrocarbon group or C 1-10 alkoxy-substituted C 1-10 alkyl; M is Ti, Zr, or Hf; Each R 1 Same or different, and for C 1-6 Alkyl or C 1-6 Alkoxy; Each n is between 1 and 2; Each R 2 Same or different, and for C 1-6 Alkyl, C 1-6 Alkoxy or -Si(R)3 group; Each R can be optionally divided by 1 to 3 Cs. 1-6 Alkyl-substituted C 1-10 Alkyl or phenyl; Each p is between 0 and 1.

10. A membrane comprising a metallocene-catalyzed multimodal polyethylene copolymer (P) according to any one of claims 1 to 9.

11. The membrane according to claim 10, wherein, The membrane comprises at least one layer comprising a metallocene-catalyzed multimodal polyethylene copolymer (P), wherein the at least one layer comprises at least 50 wt%, more preferably at least 60 wt%, even more preferably at least 70 wt%, and still more preferably at least 80 wt% of the metallocene-catalyzed multimodal polyethylene copolymer (P) according to any one of claims 1 to 9.

12. The membrane according to any one of claims 10 to 11, wherein, As described in the experimental section, the seal initiation temperature (SIT) measured using a 40 µm blown film satisfies inequality (X): ， In the formula, MFR2HMW is the MFR2 of the ethylene copolymer component (B) (190 °C, 2.16 kg, ISO 1133), and the MFR2 of the ethylene copolymer component (B) is calculated according to formula (II-b): ， In the formula, x represents the weight fraction of the ethylene copolymer component (A) relative to the multimodal polyethylene copolymer (P). MFR(B) is the calculated MFR2 of the ethylene copolymer component (B). MFR(P) is MFR2 of multimodal polyethylene copolymer (P) (190 °C, 2.16 kg, ISO 1133).

13. The membrane according to any one of claims 10 to 12, wherein, The membrane has the following characteristics: the dart impact strength (DDI) measured by a 40 μm monolayer blown film according to ISO 7765-1:1988 / Method A is at least 1100g to 2500g, preferably 1300g to 2300g, and more preferably 1500g to 2200g.

14. Use of the film according to any one of claims 10 to 13 as a packaging material, particularly as a packaging material for food and / or medical products.

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