Copolymer

Abstract

The present invention provides a metallocene catalyzed multimodal ethylene-1-butene random copolymer having a density in the range of 910 kg / m3 to 930 kg / m3, an MFR2 in the range of 0.1 g / 10 min to 3.0 g / 10 min as determined according to ISO 1133 at 190 DEG C and 2.16 kg, a 1-butene content in the range of 1.0 to 20 wt%, a separated 1-butene comonomer unit amount (EBE%) greater than 97.0%, and a metallocene catalyzed multimodal ethylene-1-butene random copolymer having a density in the range of 910 kg / m3 to 930 kg / m3, an MFR2 in the range of 0.1 g / 10 min to 3.0 g / 10 min as determined according to ISO 1133 at 190 DEG C and 2.16 kg. Wherein the amount of separated 1-butene comonomer units is calculated according to formula (I) wherein EBE represents the amount (kCb) of comonomer sequences of ethylene, 1-butene and ethylene per 1000 carbons, EBB represents the amount (kCb) of comonomer sequences of ethylene, 1-butene and 1-butene per 1000 carbons, BBB represents the amount (kCb) of comonomer sequences of three consecutive 1-butenes per 1000 carbons, and wherein EBE represents the amount (kCb) of comonomer sequences of ethylene, 1-butene and 1-butene per 1000 carbons, EBB represents the amount (kCb) of comonomer sequences of three consecutive 1-butenes per 1000 carbons, and BBB represents the amount (kCb) of comonomer sequences of ethylene, 1-butene and 1-butene per 1000 carbons. As described in Assay Methods; and the ratio of MFR21 as determined according to ISO 1133 at 190 DEG C and 21.6 kg to MFR2 as determined according to ISO 1133 at 190 DEG C and 2.16 kg, MFR21 / MFR2, is in the range of 22 to 100. # imgabs0 #

Description

[0001] The present invention relates to a metallocene-catalyzed multimodal polyethylene copolymer and a process for preparing such a copolymer. In particular, the present invention relates to a metallocene-catalyzed multimodal ethylene-1-butene copolymer having specific properties that make it attractive for film applications. The present invention also relates to a polymer composition comprising said copolymer and films and related articles prepared from such copolymer. Background Art

[0002] Polymer films are widely used in packaging. These films must clearly protect the package contents from damage and environmental influences.

[0003] Polyethylene films, especially films made from linear low-density polyethylene (LLDPE), are widely used in packaging due to their excellent cost-performance ratio.

[0004] Unimodal polyethylene (PE) polymers, such as SSC products, are typically used for film applications. Unimodal PE polymers have, for example, good optical properties, such as low haze, but melt processing of such polymers is not satisfactory, for example, from a production point of view, and may also lead to quality problems in the final product. Multimodal PE polymers with two or more different polymer components process better, but melt homogenization of, for example, multimodal PE may be problematic, leading to an inhomogeneous final product, for example as evidenced by a high gel content in the final product.

[0005] There is a growing need to find multimodal PE polymers with different property balances to provide tailor-made solutions to meet the growing needs of end-use manufacturers, for example to reduce production costs while maintaining or even improving end-product properties. Tailor-made polymer solutions are also needed to meet the requirements of evolving equipment technologies in end-use areas.

[0006] One of the most widely used comonomers in multimodal PE polymers is 1-butene. However, despite its easy availability, 1-butene has the disadvantage that the resulting polymer does not have all the properties required for film applications, in particular a good balance between mechanical, optical and sealing properties.

[0007] Therefore, there is a need in the art to provide an ethylene-1-butene material that provides low seal initiation temperature, good optical properties and mechanical properties, especially dart drop (impact strength). In other words, there is a need for a material that provides a favorable combination of preferred sealing performance, good optical and mechanical properties, especially SIT, haze and dart drop performance to films prepared from such materials. Therefore, there is a need to develop new ethylene-1-butene copolymers that provide an improved balance of properties.

[0008] WO 2021 / 013552 discloses a polyethylene composition comprising a base resin, wherein the base resin comprises a first ethylene-1-butene portion and a second ethylene-1-butene portion. MFR of an exemplary composition 21 The ratio of MFR (190℃, 21.6kg, ISO1133) to MFR2 (190℃, 2.16kg, ISO 1133) (MFR 21 / MFR2) is 20.

[0009] The present inventors have surprisingly found that a specific class of metallocene-catalyzed multimodal ethylene-1-butene random copolymers possess an attractive balance of mechanical, optical and sealing properties when used in film applications. Summary of the invention

[0010] From one aspect, the present invention provides a metallocene-catalyzed multimodal ethylene-1-butene random copolymer having a density of 910 kg / m 3 Up to 930kg / m 3 in the range of 0.1 g / 10 min to 3.0 g / 10 min, the 1-butene content in the range of 1.0 to 20 wt%,

[0011] The amount of isolated 1-butene comonomer units (EBE%) is greater than 97%,

[0012] The amount of the separated 1-butene comonomer units is calculated according to formula (I):

[0013]

[0014] wherein EBE represents the amount of the comonomer sequence of ethylene, 1-butene and ethylene per 1000 carbons (kCb), EBB represents the amount of the comonomer sequence of ethylene, 1-butene and 1-butene per 1000 carbons (kCb), and BBB represents the amount of the comonomer sequence of three consecutive 1-butenes per 1000 carbons (kCb), as described in “Determination Methods”; and

[0015] MFR measured according to ISO 1133 at 190°C and 21.6 kg 21 Ratio MFR to MFR2 measured according to ISO 1133 at 190°C and 2.16 kg 21 / MFR2 is in the range of 22 to 100.

[0016] Viewed from a further aspect the invention provides a process for preparing a metallocene-catalysed multimodal ethylene-1-butene random copolymer as hereinbefore defined, the process comprising:

[0017] (i) in a first polymerization stage, polymerizing ethylene and 1-butene together in the presence of a metallocene catalyst to produce a first ethylene polymer;

[0018] (ii) polymerizing ethylene together with 1-butene in the presence of the catalyst and the first ethylene polymer in a second polymerization stage to prepare an ethylene polymer mixture comprising the first ethylene polymer and a second ethylene polymer; and

[0019] (iii) in a third polymerization stage, polymerizing ethylene together with 1-butene in the presence of said catalyst and said ethylene polymer mixture to prepare said multimodal ethylene-1-butene random copolymer.

[0020] Viewed from another aspect the invention provides a composition comprising the metallocene catalysed multimodal ethylene-1-butene random copolymer as hereinbefore defined and from 5 to 30 wt% low density polyethylene (LDPE) relative to the total weight of the composition.

[0021] Viewed from a further aspect the invention provides a film comprising the metallocene catalysed multimodal ethylene-1-butene random copolymer as hereinbefore defined or the composition as hereinbefore defined.

[0022] Viewed from another aspect the invention provides an article, preferably a packaging article, comprising a film as hereinbefore defined.

[0023] Detailed description

[0024] definition

[0025] When the term "comprising" is used in the present description and claims, it does not exclude other not specifically stated elements of major or minor functional importance. For the purposes of the present invention, the term "consisting of" is regarded as a preferred embodiment of the term "comprising of". If hereinafter a group is defined as comprising at least a certain number of embodiments, this should also be understood to disclose a group that preferably consists only of these embodiments.

[0026] Whenever the terms "including" or "having" are used, these terms are intended to be equivalent to "comprising" as defined above.

[0027] When referring to a singular noun, using an indefinite or definite article, for example "a", "an" or "the", this includes a plural of that noun unless something else is specifically stated.

[0028] Metallocene-catalyzed multimodal ethylene-1-butene random copolymer is defined in the present invention as a multimodal ethylene-1-butene random copolymer produced in the presence of a metallocene catalyst.

[0029] The term "random copolymer" in the context of the present invention is understood to mean ethylene copolymers wherein the comonomer units (in the present case 1-butene) are randomly distributed in the copolymer.

[0030] The term "multimodal" herein means that the ethylene polymer components and preferably the ethylene polymer fractions (A-1) and (A-2) have multimodality in melt flow rate (MFR), i.e. the ethylene polymer components and / or fractions (A-1) and (A-2) have different MFR values. The multimodal ethylene-1-butene random copolymer may have further multimodality in one or more other properties between the ethylene polymer components and between fractions (A-1) and (A-2), as described below.

[0031] The multimodal ethylene-1-butene random copolymer of the present invention as defined above, below or in the claims is also referred to herein as "multimodal polyethylene", "multimodal PE" or "multimodal copolymer". In addition, it is sometimes referred to as "polyethylene" of the present invention.

[0032] The following preferred embodiments, properties and subgroups of the multimodal PE and its ethylene polymer components (A) and (B), as well as preferred ethylene polymer fractions (A-1) and (A-2) and the inventive films, including preferred ranges thereof, are independently generalizable such that they can be used in any order or combination to further define preferred embodiments of the multimodal PE and the inventive articles.

[0033] Metallocene-catalyzed multimodal ethylene-1-butene random copolymers

[0034] It has been found that the multimodal ethylene-1-butene random copolymers according to the invention provide an improved material for film applications combining very good sealing properties and mechanical properties, e.g. in terms of dart drop intensity (DDI), with excellent optical properties, e.g. in terms of haze.

[0035] The polymer of the present invention is a multimodal ethylene-1-butene random copolymer, which may also be referred to as an ethylene copolymer. An ethylene copolymer refers to a polymer whose majority weight comes from ethylene monomer units (i.e. at least 50 wt% is ethylene relative to the total weight of the copolymer). It should be understood that the ethylene-1-butene copolymer of the present invention contains only ethylene and 1-butene monomer units.

[0036] The 1-butene content of the copolymer is in the range of 1.0 to 20 wt% relative to the total weight of the copolymer as a whole. The contribution of the comonomer (1-butene) relative to the total weight of the copolymer as a whole is preferably 5.0 to 15 wt%, more preferably 8.0 to 10 wt%.

[0037] The polymer of the present invention is multimodal and therefore comprises at least two components. The polymer is preferably bimodal. The polymer of the present invention most preferably comprises

[0038] (A) a lower molecular weight ethylene-1-butene copolymer component, and

[0039] (B) A higher molecular weight ethylene-1-butene copolymer component.

[0040] The polyethylene of the present invention is multimodal. Usually, a polyethylene composition comprising at least two polyethylene components, which are produced under different polymerization conditions, resulting in different (weight average) molecular weights and molecular weight distributions of the components, is called "multimodal". Therefore, in this sense, the composition of the present invention is a multimodal polyethylene. The prefix "multi" is related to the number of different polymer components that make up the composition. The polyethylene may also be multimodal with respect to the comonomer content.

[0041] The form of the molecular weight distribution curve of such a multimodal polyethylene, ie a plot of the polymer weight fractions as a function of their molecular weight, will show two or more maxima, or at least will be significantly broadened compared to the curves for the individual fractions.

[0042] For example, if a polymer is produced in a continuous multi-stage process utilizing reactors in series and using different conditions in each reactor, the polymer fractions produced in the different reactors will each have different molecular weight distributions and weight average molecular weights. When a molecular weight distribution curve for such a polymer is recorded, the individual curves for these fractions are superimposed on the molecular weight distribution curve for the total resulting polymer product, typically resulting in a curve having two or more distinct maxima.

[0043] The copolymer of the present invention has an MFR2 of 0.1 g / 10 min to 3.0 g / 10 min. The preferred range of MFR2 is 0.5 g / 10 min to 2.0 g / 10 min, such as 0.8 g / 10 min to 1.5 g / 10 min.

[0044] The MFR of the copolymer of the present invention is 21 It is 15 g / 10 min to 80 g / 10 min, for example 20 g / 10 min to 70 g / 10 min, most preferably 25 g / 10 min to 60 g / 10 min.

[0045] The MFR of the copolymer of the present invention is 21The flow rate ratio (FRR) of MFR / MFR2 is in the range of 22 to 100. Preferably, MFR 21 The flow rate ratio (FRR) of the polymer of the present invention is at least 24.0, more preferably at least 25.0. 21 The flow rate ratio (FRR) of MFR / MFR2 is preferably at most 70.0, such as at most 55.0, more preferably at most 40.0. 21 The preferred range of the ratio of MFR (190°C, 21.6 kg, ISO 1133) to MFR2 (190°C, 2.16 kg, ISO 1133) is 22 to 70, more preferably 24 to 55, even more preferably 25 to 40.

[0046] According to ISO 1183, the density of the copolymer is 910 kg / m 3 Up to 930kg / m 3 Therefore, the copolymers of the present invention are generally considered to be linear low density polyethylenes (LLDPEs). Preferably, the density of the polymer is 911 kg / m 3 Up to 928kg / m 3 , more preferably 912kg / m 3 Up to 925kg / m 3 , for example 913kg / m 3 Up to 922kg / m 3 .

[0047] Furthermore, the copolymers of the present invention are characterized in that the amount of isolated 1-butene comonomer units (EBE%) is greater than 97.0%,

[0048] The amount of the separated 1-butene comonomer units is calculated according to formula (I):

[0049]

[0050] Where EBE represents the amount of the comonomer sequence of ethylene, 1-butene and ethylene per 1000 carbons (kCb), EBB represents the amount of the comonomer sequence of ethylene, 1-butene and 1-butene per 1000 carbons (kCb), and BBB represents the amount of the comonomer sequence of three consecutive 1-butenes per 1000 carbons (kCb);

[0051] A preferred range of EBE% is 97.5 to 100%, such as 98.0 to 100%, such as 98.5 to 100%.

[0052] The copolymer of the present invention is multimodal and thus comprises at least a lower molecular weight component (A) and a higher molecular weight component (B). In a particularly preferred embodiment, the copolymer consists of components (A) and (B). The weight ratio of component (A) to component (B) in the composition is in the range of 30:70 to 70:30, more preferably 35:65 to 65:35, most preferably 40:60 to 60:40. In some embodiments, the ratio may be 35 wt% to 50 wt% of component (A) and 50 wt% to 65 wt% of component (B), for example 40 wt% to 50 wt% of component (A) and 50 wt% to 60 wt% of component (B), wherein the wt% values ​​are relative to the total weight of the multimodal polyethylene copolymer.

[0053] In a particularly preferred embodiment, the wt % values ​​of components (A) and (B) add up to 100%.

[0054] Each of component (A) and component (B) is an ethylene copolymer. The term "ethylene copolymer" is as defined above.

[0055] The MFR2 (190°C, 2.16 kg, ISO 1133) of the lower molecular weight component (A) is typically 2.0 to 300 g / 10 min, preferably 2.0 to 200 g / 10 min, more preferably 2.8 to 150 g / 10 min, even more preferably 3.0 to 100 g / 10 min, e.g. 3.2 to 40 g / 10 min.

[0056] The density of component (A) is usually 915 kg / m 3 Up to 975kg / m 3 , preferably 920kg / m 3 Up to 960kg / m 3 , more preferably 930kg / m 3 Up to 950kg / m 3 , for example 933kg / m 3 Up to 942kg / m 3 .

[0057] Component (A) is an ethylene-1-butene copolymer.

[0058] The MFR2 of the higher molecular weight component (B) is typically 0.001 g / 10min to 1.5 g / 10min, preferably 0.01 g / 10min to 1.5 g / 10min, more preferably 0.05 g / 10min to 1.5 g / 10min, even more preferably 0.1 g / 10min to 1.2 g / 10min, e.g. 0.2 g / 10min to 1.0 g / 10min.

[0059] The density of component (B) is usually 880 kg / m 3 Up to 910kg / m 3 , preferably 885kg / m 3 Up to 905kg / m 3 , for example 890kg / m 3 Up to 900kg / m 3 .

[0060] Component (B) is an ethylene-1-butene copolymer.

[0061] In a particularly preferred embodiment, the copolymer of the invention comprises, preferably consists of:

[0062] (i) 30.0 to 70.0 wt% of an ethylene-1-butene polymer component (A), and

[0063] (ii) 70.0 to 30.0 wt% of the ethylene-1-butene polymer component (B).

[0064] The amounts of (A) and (B) preferably total 100.0 wt%.

[0065] In one embodiment of the present invention, the ethylene-1-butene polymer component (A) consists of an ethylene polymer portion (A-1) and an ethylene polymer portion (A-2). In the case where the ethylene-1-butene polymer component (A) consists of an ethylene polymer portion (A-1) and (A-2), the MFR2 of the ethylene polymer portions (A-1) and (A-2) may be different from each other.

[0066] The MFR2 (190°C, 2.16 kg, ISO 1133) of the ethylene polymer portion (A-1) is generally in the range of 1.0 g / 10 min to 300 g / 10 min, preferably 1.0 g / 10 min to 200 g / 10 min, more preferably 1.5 g / 10 min to 150 g / 10 min, even more preferably 2.0 g / 10 min to 100 g / 10 min, particularly preferably 2.5 g / 10 min to 80 g / 10 min, for example 3.0 g / 10 min to 40 g / 10 min.

[0067] The MFR2 (190°C, 2.16 kg, ISO 1133) of the ethylene polymer portion (A-2) may be in the range of 1.0 g / 10 min to 300 g / 10 min, preferably 3.0 g / 10 min to 40.0 g / 10 min, more preferably 3.2 g / 10 min to 30.0 g / 10 min, even more preferably 3.5 g / 10 min to 20.0 g / 10 min and most preferably 3.5 g / 10 min to 10.0 g / 10 min.

[0068] The MFR2 of the ethylene polymer components (A) and (B) are different from each other.

[0069] The MFR2 (190°C, 2.16 kg, ISO 1133) of the ethylene polymer component (A) is preferably in the range of 2.0 g / 10min to 300 g / 10min, preferably 2.0 g / 10min to 200 g / 10min, more preferably 2.8 g / 10min to 150 g / 10min, even more preferably 3.0 g / 10min to 100 g / 10min, for example 3.2 g / 10min to 40 g / 10min.

[0070] The MFR2 (190°C, 2.16 kg, ISO 1133) of the ethylene polymer component (B) is preferably in the range of 0.001 g / 10min to 1.5 g / 10min, preferably 0.01 g / 10min to 1.5 g / 10min, more preferably 0.05 g / 10min to 1.5 g / 10min, even more preferably 0.1 g / 10min to 1.2 g / 10min, for example 0.2 g / 10min to 1.0 g / 10min.

[0071] In one embodiment of the present invention, it is preferred that the ratio of the MFR2 (190°C, 2.16 kg, ISO 1133) of the ethylene-1-butene polymer component (A) to the MFR2 (190°C, 2.16 kg, ISO 1133) of the final multimodal copolymer is at least 2.5 to 300, preferably 3.0 to 150, more preferably 3.5 to 100.

[0072] Naturally, besides the multimodality with respect to, i.e. the difference between, the MFR2 of the ethylene polymer components (A) and (B), the multimodal PE of the present invention may also be multimodal, e.g. with respect to one or both of the other two properties:

[0073] Multimodality is about the difference between

[0074] - the comonomer content present in the ethylene polymer components (A) and (B); and / or

[0075] - the density of the ethylene polymer components (A) and (B).

[0076] Preferably, the multimodal copolymer is further multimodal with respect to the comonomer content of the ethylene polymer components (A) and (B).

[0077] The comonomer content of components (A) and (B) can be measured, or, in the preferred case, one component is first produced and 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:

[0078] Comonomer content in component B (wt%) = (comonomer content in final product (wt%) - (weight fraction of component A * comonomer content in component A (wt%)) / (weight fraction of component B)

[0079] Even more preferably, the multimodal copolymer of the present invention is further multimodal with respect to the difference in density between ethylene copolymer component (A) and ethylene copolymer component (B). Preferably, the density of ethylene copolymer component (A) is different from, preferably higher than, the density of ethylene copolymer component (B).

[0080] The density of the ethylene copolymer component (A) is usually 915 kg / m 3 Up to 975kg / m 3 In the range of 920kg / m 3 Up to 960kg / m 3 , more preferably 930kg / m 3 Up to 950kg / m 3 , for example 933kg / m 3 Up to 942kg / m 3 , and / or the density of the ethylene polymer component (B) is 880 kg / m 3 Up to 910kg / m 3 In the range of 885kg / m 3 Up to 905kg / m 3 , more preferably 890kg / m 3 Up to 900kg / m 3 .

[0081] The density of the polymer part (A-1) is usually 915 kg / m 3 Up to 975kg / m 3 In the range of 925kg / m 3 Up to 955kg / m 3 , more preferably 930kg / m 3 Up to 950kg / m 3 , for example 935kg / m 3 Up to 945kg / m 3 .

[0082] The density of the polymer part (A-2) is preferably 915 kg / m 3 Up to 975kg / m 3 In the range of 935kg / m 3 Up to 945kg / m 3 .

[0083] Within the scope of the present invention, the first and second ethylene polymer parts (A-1 and A-2) of the ethylene polymer component (A) may be present in a weight ratio of 4:1 to up to 1:4, for example 3:1 to 1:3, or 2:1 to 1:2, or 1:1.

[0084] The ethylene polymer component (A) is present in an amount of 30.0 to 70.0 wt%, preferably 32.0 to 55.0 wt%, even more preferably 34.0 to 45.0 wt%, based on the multimodal copolymer.

[0085] Thus, the ethylene polymer component (B) is present in an amount of 70.0 to 30.0 wt%, preferably 68.0 to 45.0 wt%, more preferably 66.0 to 55.0 wt%, based on the multimodal copolymer.

[0086] Preparation of multimodal ethylene copolymers

[0087] The metallocene-catalyzed multimodal copolymers may be produced in a two-stage process, preferably comprising a slurry reactor (loop reactor), wherein the slurry (loop) reactor is connected in series with a gas phase reactor (GPR), wherein a low molecular weight polymer component is produced in the loop reactor and a high molecular weight polymer component is produced in the GPR in the presence of the low molecular weight polymer component to produce the multimodal copolymer.

[0088] In case the ethylene component (A) of the multimodal copolymer consists of ethylene polymer fractions (A-1) and (A-2), the multimodal copolymer may be produced in a three stage process, preferably comprising a first slurry reactor (loop reactor 1), wherein the first slurry loop reactor is connected in series with a further slurry reactor (loop reactor 2), such that the first ethylene polymer fraction (A-1) produced in the loop reactor 1 is fed to the loop reactor 2, wherein the second ethylene polymer fraction (A-2) is produced in the presence of the first fraction (A-1). The loop reactor 2 is thereby connected in series with a gas phase reactor (GPR), such that the first ethylene copolymer fraction (A) leaving the second slurry reactor is fed to the GPR to produce the polyethylene copolymer.

[0089] Such processes are described inter alia in WO 2016 / 198273, WO 2021009189, WO 2021009190, WO 2021009191 and WO 2021009192. Full details of how to prepare suitable metallocene-catalyzed multimodal copolymers can be found in these references.

[0090] A suitable method is the Borstar PE method or the Borstar PE 3G method.

[0091] Therefore, the metallocene-catalyzed multimodal copolymer according to the present invention is preferably prepared in a loop-loop gas cascade. This polymerization step may be preceded by a prepolymerization step. The purpose of the prepolymerization is to polymerize a small amount of polymer onto the catalyst at low temperature and / or low monomer concentration. By prepolymerization, the performance of the catalyst in the slurry can be improved and / or the properties of the final polymer can be changed. The prepolymerization step is preferably carried out in a slurry, and the amount of polymer produced in the optional prepolymerization step is included in the amount of ethylene polymer component (A) (mass percentage (wt%)).

[0092] When there is a prepolymerization step, the catalyst components are preferably all introduced into the prepolymerization step. However, when the solid catalyst components and the cocatalyst can be fed separately, only a portion of the cocatalyst can be introduced into the prepolymerization stage, and the remainder into the subsequent polymerization stage. Also in this case, it is necessary to introduce so much cocatalyst into the prepolymerization stage in order to obtain a sufficient polymerization reaction therein.

[0093] It is understood that within the scope of the present invention the amount of polymer produced in the prepolymerisation is within 1 to 5 wt% relative to the final metallocene catalysed multimodal copolymer. This can be counted as part of the first ethylene-1-butene copolymer component (A).

[0094] catalyst

[0095] The metallocene-catalyzed multimodal copolymer of the present invention is prepared using a metallocene catalyst. The metallocene catalyst comprises a metallocene complex and a cocatalyst. The metallocene compound or complex is also referred to herein as an organometallic compound (C).

[0096] The organometallic compound (C) comprises a transition metal (M) from Groups 3 to 10 of the Periodic Table of Elements (IUPAC 2007) or from the actinides or lanthanides.

[0097] According to the present invention, the term "organometallic compound (C)" includes any metallocene or non-metallocene compound of a transition metal, which carries at least one organic (coordinating) ligand and exhibits catalytic activity alone or together with a cocatalyst. Transition metal compounds are well known in the art, and the present invention encompasses compounds of metals of Groups 3 to 10, e.g. Groups 3 to 7 or Groups 3 to 6, e.g. Groups 4 to 6, of the Periodic Table of the Elements (IUPAC 2007), as well as compounds of lanthanides or actinides.

[0098] In a preferred embodiment, the organometallic compound (C) is a bridged metallocene complex, ie a complex comprising a bridging ligand between the metallocene ligands.

[0099] In a further preferred embodiment, the organometallic compound (C) has the following formula (II):

[0100]

[0101] Wherein each X is independently a halogen atom, C 1-6 Alkyl, C 1-6 alkoxy, phenyl or benzyl;

[0102] Each Het is independently a monocyclic heteroaromatic group containing at least one heteroatom selected from O or S;

[0103] L is -R'2Si-, wherein each R' is independently C 1-20 A hydrocarbon group or a C substituted alkoxy group having 1 to 10 carbon atoms 1-10 alkyl;

[0104] M is Ti, Zr or Hf;

[0105] Each R 1 Same or different, C 1-6 Alkyl or C 1-6 Alkoxy;

[0106] Each n is 1 to 2;

[0107] Each R 2 Same or different, C 1-6 Alkyl, C 1-6 Alkoxy or -Si(R)3 group;

[0108] Each R is C 1-10 Alkyl or optionally 1 to 3 C 1-6 Alkyl-substituted phenyl; and

[0109] Each p is from 0 to 1.

[0110] Preferably, the compound of formula (II) has the following structure:

[0111]

[0112] Wherein each X is independently a halogen atom, C 1-6 Alkyl, C 1-6 alkoxy, phenyl or benzyl;

[0113] L is Me2Si-;

[0114] Each R 1 Same or different, C 1-6 an alkyl group, such as methyl or tert-butyl;

[0115] Each n is 1 to 2;

[0116] R 2 is -Si(R)3 alkyl; each p is 1;

[0117] Each R is C 1-6 Alkyl or phenyl.

[0118] Highly preferred complexes of formula (II) are

[0119]

[0120] Most preferably, the complex dimethylsilanediylbis[2-(5-trimethylsilylfuran-2-yl)-4,5-dimethylcyclopentadien-1-yl]zirconium dichloride is used.

[0121] It is particularly preferred that the metallocene catalyst contains only a single metallocene complex. It is further preferred that the single metallocene complex is a bridged metallocene complex or a complex having the above structure.

[0122] More preferably, the high molecular weight and low molecular weight components of the multimodal copolymer are produced using the same metallocene catalyst, ie are produced in the presence of the same metallocene catalyst.

[0123] To form the catalyst, a cocatalyst known in the art, also called an activator, is used. Cocatalysts containing Al or B are well known and can also be used here. Preferably, an aluminoxane (e.g. methylaluminoxane) or a boron-based cocatalyst (e.g. borates) is used.

[0124] In contrast to Ziegler Natta catalysis, polyethylene copolymers prepared using single-site catalysis have characteristics that distinguish them from Ziegler Natta materials. In particular, the comonomer distribution is more uniform. This can be shown by TREF or Crystaf techniques. Catalyst residues can also indicate the catalyst used. For example, Ziegler Natta catalysts do not contain Zr or Hf group (IV) metals.

[0125] The metallocene-catalyzed multimodal ethylene-1-butene random copolymer may contain other polymer components and optional additives and / or fillers. In the case where the metallocene-catalyzed multimodal copolymer contains an additional polymer component, the amount of the additional polymer component typically varies between 3.0 and 20.0 wt%, based on the combined amount of the metallocene-catalyzed multimodal copolymer and the other polymer components.

[0126] Optional additives and fillers and the amounts used are conventional in the field of film applications. Examples of such additives are, inter alia, antioxidants, processing stabilizers, UV stabilizers, pigments, fillers, antistatic additives, antiblocking agents, nucleating agents, acid scavengers and polymer processing aids (PPAs).

[0127] It is to be understood in the present context that any additive and / or filler may optionally be added to a so-called masterbatch comprising the respective additive and a carrier polymer. In this case, the carrier polymer is not included in the polymer component of the metallocene-catalyzed multimodal copolymer, but is included in the amount of the respective additive based on the total amount (100 wt %) of the polymer composition.

[0128] Composition

[0129] The present invention also relates to a polymer composition comprising the metallocene-catalyzed multimodal ethylene-1-butene random copolymer as defined above and 5 to 30 wt% of low density polyethylene (LDPE), relative to the total weight of the composition.

[0130] Low density polyethylene (LDPE) is polyethylene produced using a high pressure process. Typically, the polymerization of ethylene and optionally other comonomers in a high pressure process is carried out in the presence of an initiator. The meaning of the term LDPE is well known and documented in the literature. The term LDPE describes and distinguishes high pressure polyethylene from low pressure polyethylene produced in the presence of an olefin polymerization catalyst. LDPEs have certain typical characteristics, such as a different branching structure. LDPE has a typical density range of 0.910 g / cm 3 Up to 0.940g / cm 3 .

[0131] Low density polyethylene (LDPE) is a vinyl polymer. As used herein, the term "vinyl polymer" refers to a polymer comprising a majority weight percent of polymerized ethylene monomers (based on the total weight of polymerizable monomers), and optionally may comprise at least one polymerized comonomer. The vinyl polymer may comprise greater than 50 wt%, or greater than 60 wt%, or greater than 70 wt%, or greater than 80 wt%, or greater than 90 wt% of units derived from ethylene (based on the total weight of the vinyl polymer).

[0132] LDPE can be a low density homopolymer of ethylene (herein referred to as LDPE homopolymer) or a low density copolymer of ethylene and one or more comonomers (herein referred to as LDPE copolymer). The one or more comonomers of the LDPE copolymer are preferably selected from polar comonomers, non-polar comonomers or a mixture of polar comonomers and non-polar comonomers. In addition, the LDPE homopolymer or LDPE copolymer can be optionally unsaturated.

[0133] If the LDPE is a copolymer, it preferably comprises less than 10 wt%, more preferably less than 7 wt%, even more preferably less than 5 wt%, for example less than 3 wt% of comonomer relative to the total weight of the copolymer.

[0134] Preferably, LDPE is a homopolymer.

[0135] The LDPE used in the composition of the present invention may have a 3 Up to 940kg / m 3 , preferably 918kg / m 3 Up to 935kg / m 3 , especially 920kg / m 3 Up to 932kg / m 3 , for example, about 922kg / m 3 Up to 930kg / m 3 density.

[0136] The MFR2 (2.16 kg, 190° C.) of the LDPE polymer is preferably from 0.05 g / 10 min to 30.0 g / 10 min, more preferably from 0.1 g / 10 min to 20 g / 10 min, and most preferably from 0.1 g / 10 min to 10 g / 10 min, especially from 0.1 g / 10 min to 5.0 g / 10 min. In a preferred embodiment, the MFR2 of the LDPE is from 0.1 g / 10 min to 4.0 g / 10 min, especially from 0.3 g / 10 min to 4.0 g / 10 min, especially from 0.5 g / 10 min to 3.0 g / 10 min.

[0137] LDPE polymer is produced by free radical initiated polymerization under high pressure, known as high pressure (HP) free radical polymerization. The HP reactor can be, for example, a well-known tubular reactor or an autoclave reactor or a mixture thereof, preferably a tubular reactor. High pressure (HP) polymerization and the adjustment of process conditions to further adjust other properties of the polyolefin according to the desired end application are well known and described in the literature and can be easily used by the skilled person. Suitable polymerization temperatures range up to 400° C., preferably 80 to 350° C., and pressures of 70 MPa, preferably 100 to 400 MPa, more preferably 100 to 350 MPa. The pressure can be measured at least after the compression stage and / or after the tubular reactor. In all steps, the temperature can be measured at several points.

[0138] After separation, the LDPE obtained is generally in the form of a polymer melt, which is generally mixed and pelletized in a pelletizing section (such as a pelletizing extruder) connected to the HP reactor system. Optionally, additives, such as antioxidants, can be added to the mixer in a known manner.

[0139] For more details on the production of ethylene (co)polymers by high pressure free radical polymerization, see Encyclopedia of Polymer Science and Engineering, Vol. 6 (1986), pp. 383-410 and Encyclopedia of Materials: Science and Technology, 2001, Elsevier Science Ltd.: "Polyethylene: High Pressure", R. Klimesch, D. Littmann and F.-O. Pages 7181-7184.

[0140] LDPE (i) is present in an amount of 5 to 30 wt%, preferably 6 to 25 wt%, more preferably 7 to 20 wt%, such as 8 to 15 wt%, relative to the total weight of the composition as a whole.

[0141] membrane

[0142] The film of the present invention comprises at least one layer comprising a metallocene-catalyzed multimodal ethylene-1-butene random copolymer. The film may be a monolayer film comprising a metallocene-catalyzed multimodal ethylene-1-butene random copolymer or a multilayer film, wherein at least one layer comprises a metallocene-catalyzed multimodal ethylene-1-butene random copolymer.

[0143] The terms "single-layer film" and "multi-layer film" have well-known meanings in the art. Thus, the film of the present invention may comprise a single layer (i.e., a monolayer) or may be multi-layered. A multi-layer film typically and preferably comprises at least 3 layers.

[0144] The layers of the monolayer or multilayer film of the present invention may consist of the metallocene-catalyzed multimodal ethylene-1-butene random copolymer itself, or of a blend of the metallocene-catalyzed multimodal ethylene-1-butene random copolymer with other polymers. In the case of a blend, any other polymer is different from the metallocene-catalyzed multimodal ethylene-1-butene random copolymer and is preferably a polyolefin. A portion of the above-mentioned additives, such as processing aids, may be optionally added to the metallocene-catalyzed multimodal ethylene-1-butene random copolymer during the film preparation process.

[0145] Preferably, at least one layer of the film of the present invention 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-catalyzed multimodal ethylene-1-butene random copolymer of the present invention. Most preferably, said at least one layer of the film of the present invention consists of a metallocene-catalyzed multimodal ethylene-1-butene random copolymer.

[0146] The film is preferably produced by any conventional film extrusion method 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, a blown film is produced by extruding through an annular die and blowing into a tubular film by forming bubbles, which collapse between the pressure rollers after solidification. The film can then be cut, cut or converted (e.g., gusseted) as required. Traditional film production techniques can be used in this regard. If the preferred blown or cast film is a multilayer film, each layer is usually coextruded. Those skilled in the art will know suitable extrusion conditions.

[0147] The film according to the present invention may be subjected to post-treatment processes such as surface modification, lamination or orientation processes etc. Such orientation processes may be uniaxial (MDO) or biaxial orientation, wherein uniaxial orientation is preferred.

[0148] In another embodiment, the film is unoriented.

[0149] The resulting film may have any thickness conventional in the art. The thickness of the film is not important and depends on the end use. Thus, the thickness of the film may be, for example, 300 μm or less, typically 6 to 200 μm, preferably 10 to 180 μm, for example 20 to 150 μm or 20 to 120 μm. If desired, the polymer of the present invention can achieve a thickness of less than 100 μm, for example less than 50 μm.

[0150] The films of the present invention exhibit good optical properties in terms of haze transparency when measured according to ASTM D1003. The haze is typically 20.0% or less, such as 18.0 or 16.0% or less. The haze may be in the range of 2.0 to 20.0, preferably 5.0 to 18.0, more preferably 7.0 to 16.0. Preferably, the haze measurement is performed on a 40 μm film.

[0151] Furthermore, preferably, the tensile modulus (TM) of the film measured in machine direction (MD) on a 40 μm film according to ISO 527-3 is 150 to 1000 MPa, more preferably in the range of 155 to 750 MPa, still more preferably in the range of 160 to 500 MPa.

[0152] The film preferably has a seal initiation temperature (SIT) of less than 95° C., more preferably less than 91° C. Ideally, the SIT will be at least 80° C., preferably at least 85° C.

[0153] In one embodiment, the film comprising the metallocene-catalyzed multimodal ethylene-1-butene random copolymer is further characterized by a dart drop impact strength (DDI) determined according to ISO 7765-1:1988 / Method A on a 40 μm single layer test blown film of at least 200 g to 1700 g, preferably 225 g to 1000 g, more preferably 250 g to more than 750 g.

[0154] The film of the present invention may contain commonly used polymer additives, such as slip agents, UV stabilizers, pigments, antioxidants, nucleating agents, etc. These additives may be loaded on the carrier polymer in the form of a masterbatch.

[0155] For the avoidance of doubt, it is envisaged that even when each film layer is "consisting" of a specific polymer as defined above, conventional polymer additives (e.g. as described above) may be present. Thus, the term "consisting of" is not intended to exclude the presence of polymer additives. However, it excludes the presence of other polymer components used for blending. However, this is not excluded if a carrier polymer is used as part of a masterbatch. The article may not contain any other mixed polymers, but may still contain a small amount of the carrier polymer used for the masterbatch.

[0156] The films of the invention have a wide range of applications but are of particular interest in packaging. Thus, viewed from another aspect, the invention provides an article, preferably a packaging article, comprising a film as hereinbefore defined.

[0157] The present invention will be further described in detail below by way of examples:

[0158] Unless defined otherwise, the following definitions of terms and determination methods apply to the above general description of the invention as well as to the following examples.

[0159] Determination method

[0160] Amount of isolated 1-butene comonomer units (EBE%)

[0161] The amount of isolated 1-butene comonomer units (EBE%) was calculated according to formula (I):

[0162]

[0163] Where EBE represents the amount of the comonomer sequence of ethylene, 1-butene and ethylene per 1000 carbons (kCb), EBB represents the amount of the comonomer sequence of ethylene, 1-butene and 1-butene per 1000 carbons (kCb), and BBB represents the amount of the comonomer sequence of three consecutive 1-butenes per 1000 carbons (kCb).

[0164] Melt flow rate (MFR)

[0165] Melt flow rate is according to ISO 1133 at 190 ° C and 2.16 kg (MFR2) or 5.0 kg (MFR5) or 21.6 kg (MFR 21 ) measured under load.

[0166] Calculate the MFR2 of components (A) and (B)

[0167] logA=x·logB+(1-x)·logC

[0168]

[0169] B = MFR2 of component (A)

[0170] C = MFR2 of component (B)

[0171] A = Final MFR2 of the multimodal polyethylene copolymer (P) (blend)

[0172] X = weight fraction of component (A)

[0173] Flow rate ratio (FRR21 / 2)

[0174] FRR is determined as MFR 21 and MFR2.

[0175] GPC

[0176] The average molecular weights (Mz, Mw and Mn), the molecular weight distribution (MWD) and their breadth, described by the polydispersity index, PDI = Mw / Mn (wherein Mn is the number average molecular weight and Mw is the weight average molecular weight), are determined by gel permeation chromatography (GPC) according to ISO 16014-1:2003, ISO 16014-2:2003, ISO 16014-4:2003 and ASTM D 6474-12 using the following formula:

[0177]

[0178] For a constant elution volume interval ΔV i , where A i and M i and the elution volume V i The associated chromatographic peak slice area and the polyolefin molecular weight (MW), where N is equal to the number of data points between the upper and lower integration limits obtained from the chromatogram.

[0179] A high temperature GPC instrument was used, equipped with an infrared (IR) detector (IR4 or IR5 from PolymerChar (Valencia, Spain), equipped with three Agilent-PLgel Olexis columns and one Agilent-PLgel Olexis Guard column. As solvent and mobile phase, 1,2,4-trichlorobenzene (TCB) stabilized with 2,6-di-tert-butyl-4-methylphenol at 250 mg / L was used. The chromatographic system was operated at 160°C and a constant flow rate of 1 mL / min. 200 μL of sample solution was injected for each analysis. Data collection was performed using Agilent Cirrus software version 3.3 or PolymerChar GPC-IR control software.

[0180] The column set was calibrated using universal calibration (according to ISO 16014-2:2003) and 19 narrow MWD polystyrene (PS) standards in the range of 0,5 kg / mol to 11 500 kg / mol. The PS standards were dissolved at room temperature for several hours. The conversion of polystyrene peak molecular weight to polyolefin molecular weight was done by using the Mark Houwink equation and the following Mark Houwink constants:

[0181] K PS =19x10 -3 mL / g,α PS =0.655

[0182] K PE =39x10 -3 mL / g,α PE =0.725

[0183] K PP =19x10 -3 mL / g,α PP =0.725

[0184] A third-order polynomial fit was used to fit the calibration data.

[0185] All samples were prepared in the concentration range of 0.5 to 1 mg / mL and were heated at 160 °C with continuous gentle shaking for 2.5 h to dissolve PP or 3 h to dissolve PE.

[0186] Comonomer content

[0187] Quantitative analysis of microstructure by NMR spectroscopy

[0188] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content of the polymers.

[0189] Quantification 13 C{ 1 H} NMR spectra were recorded in the molten state using a Bruker Advance III 500 NMR spectrometer at 500.13 MHz and 125.76 MHz, respectively. 1 H and 13 C. All spectra were obtained using 13C optimized 7 mm magic angle spinning (MAS) probe was recorded at 150 °C, and nitrogen was used for all pneumatics. Approximately 200 mg of material was loaded into a 7 mm outer diameter zirconium oxide MAS rotor and spun at 4 kHz. This setting was chosen primarily for the high sensitivity required for rapid identification and accurate quantification (Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207: 382., Parkinson, M., Klimke, K., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2007; 208: 2128., Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau, M., Polymer 50 (2009) 2373). The standard single pulse excitation was used, using transient NOE with a short recycle delay of 3 seconds (Pollard, M., Klimke, K., Graf, R., Spiess, H. W., Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004; 37:813., Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207:382.) and the RS-HEPT decoupling scheme (Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176, 239, Griffin, J. M., Tripon, C., Samoson, A., Filip, C., and Brown, SP, Mag. Res. in Chem. 2007 45, S1, S198). A total of 1024 (1k) transients were collected for each spectrum.

[0190] A custom-made automated spectroscopic analysis program was used to quantify 13 C{ 1 H} NMR spectra were processed, integrated and quantitative properties determined. All chemical shifts were internally referenced to the bulk methylene signal (δ+) at 30.00 ppm (J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201).

[0191] A characteristic signal corresponding to the incorporation of 1-butene was observed (J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201.), and all contents were calculated relative to all other monomers present in the polymer.

[0192] A characteristic signal resulting from isolated 1-butene incorporation, namely the EEBEE comonomer sequence, was observed. The isolated 1-butene incorporation was quantified using the integral of the signal at 39.8 ppm, which was assigned to the *B2 site, to calculate the number of reporter sites per comonomer:

[0193] B=I *B2

[0194] When the characteristic signal resulting from continuous 1-butene incorporation, i.e., EBBE copolymer sequence, is observed, the integration of the signal at 39.3 ppm is used to quantify this continuous 1-butene incorporation, which is attributed to the B2B2 site and is used to calculate the number of reporter sites per comonomer:

[0195] BB=2*I ααB2B2

[0196] When the characteristic signal resulting from discontinuous 1-butene incorporation, i.e., the EBEBE copolymer sequence, was also observed, the integral of the signal at 24.7 ppm was used to quantify this discontinuous 1-butene incorporation, which was attributed to the B2B2 site and was used to calculate the number of reporter sites in each comonomer: BEB = 2*I ββB2B2

[0197] Since the *B2 and *βB2B2 sites of isolated (EEBEE) and discontinuously incorporated (EBEBE) 1-butene, respectively, overlap, the total isolated 1-butene incorporation amount was corrected according to the discontinuous 1-butene incorporation amount:

[0198] B=I *B2 -2*I ββB2B2

[0199] In the absence of other observed signals indicative of other comonomer sequences (i.e., 1-butene chain initiation), the total 1-butene comonomer content was calculated based solely on the number of isolated (EEBEE), continuous (EBBE), and discontinuous (EBEBE) 1-butene comonomer sequences:

[0200] B total =B+BB+BEB

[0201] Characteristic signals arising from saturated end groups were observed. The content of such saturated end groups was quantified using the average of the integrals of the signals at 22.8 and 32.2 ppm, which are respectively assigned to the 2s and 3s sites: S = (1 / 2)*(I 2S +I 3S )

[0202] The relative amount of ethylene is quantified using the integration of the bulk methylene (δ+) signal at 30.00 ppm: E = (1 / 2) * I δ+

[0203] The total ethylene comonomer content is calculated based on the bulk methylene signal and taking into account ethylene units present in other observed comonomer sequences or end groups:

[0204] E total =E+(5 / 2)*B+(7 / 2)*BB+(9 / 2)*BEB+(3 / 2)*S

[0205] The total mole fraction of 1-butene in the polymer is then calculated:

[0206] fB=B total / (E total +B total )

[0207] The total comonomer incorporation of 1-butene (in mole percent) is calculated in the usual manner from the mole fractions: B [mol %] = 100 * fB

[0208] The total comonomer incorporation of 1-butene (in weight percent) was calculated from the mole fractions in the standard manner:

[0209] B[wt%]=100*(fB*56.11) / ((fB*56.11)+((1-fB)*28.05))

[0210] density

[0211] Density was measured according to ISO 1183 and ISO 1872-2 for sample preparation.

[0212] Tensile modulus, tensile strength and elongation

[0213] Tensile modulus, tensile strength and elongation were measured in the machine and / or transverse directions according to ISO 527-3 on film samples prepared as described in Film Sample Preparation, with a film thickness of 40 μm and a cross head speed of 1 mm / min for modulus.

[0214] Haze

[0215] Haze, as a measure of the optical appearance of a film, was determined according to ASTM D1003 on film samples having a thickness of 40 μm.

[0216] Dart Drop Intensity (DDI): Impact resistance measured by the free-falling dart method

[0217] DDI was measured according to ISO 7765-1:1988 / Method A from films produced as shown below. This test method covers the determination of the energy to cause failure of a film under specified impact conditions of a free-falling dart from a specified height which would cause 50% of the test specimens to fail (Step Method A). Uniform missile mass increments were used during the test and after each sample test, the missile weight was reduced or increased by uniform increments depending on the result observed for the sample (failure or no failure).

[0218] Standard conditions:

[0219] Conditioning time: >96 hours

[0220] Test temperature: 23℃

[0221] Dart head material: phenolic resin

[0222] Dart diameter: 38mm

[0223] Drop height: 660mm

[0224] Sealing initiation temperature This method determines the sealing temperature range (sealing range) of polyethylene films, in particular blown films or cast films. The sealing temperature range is the temperature range over which the film can be sealed according to the conditions given below.

[0225] The lower limit (heat seal initiation temperature (SIT)) is the sealing temperature at which a seal strength of 5 N is achieved. The upper limit (seal end temperature (SET)) is reached when the film adheres to the sealing device.

[0226] The measurements were performed according to a slightly modified ASTM F1921-12, where the test parameters sealing pressure, cooling time and test speed have been modified. The force / temperature curve was continued until thermal failure of the membrane.

[0227] The sealing range was determined on a J&B 4000 Universal Sealer using films produced as shown below, with a blown film thickness of 40 μm and the following further parameters:

[0228] Conditioning time: >96 hours

[0229] Sample width: 25mm

[0230] Sealing pressure: 0.4N / mm 2 (PE)

[0231] Sealing time: 1 second

[0232] Delay time: 30 seconds

[0233] Sealing jaw size: 50×5mm

[0234] Sealing claw shape: flat

[0235] Sealing jaw coating: Niptef

[0236] Sealing temperature: ambient temperature to 240°C

[0237] Sealing temperature interval: 5°C

[0238] Starting temperature: 50℃

[0239] Clamp separation rate: 42mm / sec Example:

[0240] Material:

[0241] LLDPE1: MFR2 is 1.23g / 10min, density is 914.3kg / m 3 The m-LLDPE was produced using the polymerization parameters in Table 1.

[0242] LLDPE2: MFR2 is 1.0g / 10min, density is 915.3kg / m 3 mLLDPE, which was produced using the polymerization parameters in Table 1.

[0243] LLDPE3: MFR2 is 1.93g / 10min, density is 918kg / m 3 mLLDPE, which was produced using the polymerization parameters in Table 1.

[0244] The catalyst used to produce LLDPE1 and LLDPE2 (Cat1) contains the metallocene complex dimethylsilanediylbis[2-(5-trimethylsilylfuran-2-yl)-4,5-dimethylcyclopentadien-1-yl]zirconium dichloride. Preparation of Cat1:

[0245] Silica loading:

[0246] 10 kg of silica (PQ Corporation ES757, calcined at 600° C.) was added from a feed drum and inerted in the reactor until an O 2 level below 2 ppm was reached.

[0247] Preparation of MAO / tol / MC:

[0248] A 30wt% MAO toluene solution (14.1kg) was added from a balance to another reactor, followed by the addition of toluene (4.0kg) at 25°C (oil circulation temperature) with a stirring speed of 95rpm. After the addition of toluene, the stirring speed was increased from 95rpm to 200rpm for 30 minutes. 477g of racemic-dimethylsilanediylbis{2-(5-(trimethylsilyl)furan-2-yl)-4,5-dimethylcyclopentadiene-1-yl}zirconium dichloride metallocene was added from a metal cylinder, followed by rinsing with 4kg toluene (total toluene amount was 8.0kg). The reactor stirring speed was changed to 95rpm for MC addition and returned to 200rpm for reaction for 3 hours. After the reaction was completed, the MAO / tol / MC solution was transferred to a feed container.

[0249] Preparation of catalyst:

[0250] The reactor temperature was set to 10°C (oil circulation temperature) and the stirring speed was adjusted to 40 rpm during the addition of MAO / tol / MC. MAO / tol / MC solution (22.2 kg) was added over 205 minutes, followed by stirring for 60 minutes (oil circulation temperature was set to 25°C). After stirring, the "dry mixture" was stabilized at 25°C (oil circulation temperature) for 12 hours with a stirring speed of 0 rpm. The reactor was turned (back and forth) by 20° and stirred at a speed of 5 rpm for several rounds, once every hour.

[0251] After stabilization, the catalyst was dried at 60°C (oil circulation temperature) for 2 hours under a 2 kg / h nitrogen flow and then vacuum dried for 13 hours (under the same nitrogen flow with stirring at 5 rpm). The dried catalyst was sampled and the HC content was measured using a Sartorius moisture analyzer (model MA45) in a glove box using thermogravimetric method. The target HC level was less than 2% (actual 1.3%).

[0252] The catalyst used to produce LLDPE3 (Cat2) comprises the metallocene complex bis(1-methyl-3-n-butylcyclopentadienyl)zirconium(IV) dichloride.

[0253] Disclosed as CE1-1 in WO2022 / 018290

[0254] LLDPE4: FG5190, commercially available from Borealis, has an MFR2 of 1.2 g / 10 min and a density of 919 kg / m 3 of zn-LLDPE.

[0255] LDPE: FT5230, a commercially available LDPE from Borealis, density 923 kg / m 3, MFR2 is 0.75g / 10min.

[0256] Table 1 shows typical polymerization parameters and final polymer properties of LLDPE1, LLDPE2 and LLDPE3.

[0257] Table 1

[0258]

[0259]

[0260] The polymer was mixed with 2400 ppm of Irganox B561. 270 ppm of Dynamar FX 5922 was compounded and extruded into pellets using a JSW extruder under nitrogen atmosphere so that the SEI was 230 kWh / kg and the melt temperature was 250° C. to form pellets. The final properties are summarized in Table 2 below.

[0261] Table 2

[0262]

[0263]

[0264] Membrane preparation

[0265] The film was produced on a Collin 30 laboratory scale production line. The film thickness was 40 μm, the blow-up ratio was 1:2.5, the frost line distance was 120 cm, the melt temperature was 210 °C, and the output rate was 7 kg / h. The blending of LLDPE and LDPE was carried out directly on the blown film production line.

[0266] Table 3

[0267]

[0268]

Claims

1. A metallocene-catalyzed multimodal ethylene-1-butene random copolymer having a density of 910 kg / m3 as measured according to ISO 1183. 3 Up to 930kg / m 3 in the range of 0.1 g / 10 min to 3.0 g / 10 min, the 1-butene content in the range of 1.0 to 20 wt%, The amount of isolated 1-butene comonomer units (EBE%) is greater than 97.0%, The amount of the separated 1-butene comonomer units is calculated according to formula (I): wherein EBE represents the amount of the comonomer sequence of ethylene, 1-butene and ethylene per 1000 carbons (kCb), EBB represents the amount of the comonomer sequence of ethylene, 1-butene and 1-butene per 1000 carbons (kCb), and BBB represents the amount of the comonomer sequence of three consecutive 1-butenes per 1000 carbons (kCb), as described in "Determination Methods"; and MFR measured according to ISO 1133 at 190°C and 21.6 kg 21 Ratio MFR to MFR2 measured according to ISO 1133 at 190°C and 2.16 kg 21 / MFR2 is in the range of 22 to 100.

2. The metallocene-catalyzed multimodal ethylene-1-butene random copolymer according to claim 1, wherein the metallocene is a metallocene catalyst comprising a bridged metallocene complex, preferably a bridged metallocene complex having the following formula (II): in, Each X is independently a halogen atom, C 1-6 Alkyl, C 1-6 alkoxy, phenyl or benzyl; Each Het is independently a monocyclic heteroaromatic group containing at least one heteroatom selected from O or S; L is -R'2Si-, wherein each R' is independently C 1-20 A hydrocarbon group or a C substituted alkoxy group having 1 to 10 carbon atoms 1-10 alkyl; M is Ti, Zr or Hf; Each R 1 Same or different, C 1-6 Alkyl or C 1-6 Alkoxy; Each n is 1 to 2; Each R 2 Same or different, C 1-6 Alkyl, C 1-6 Alkoxy or -Si(R)3 group; Each R is C 1-10 Alkyl or optionally 1 to 3 C 1-6 Alkyl-substituted phenyl; and Each p is from 0 to 1.

3. The metallocene-catalyzed multimodal ethylene-1-butene random copolymer according to claim 1 or 2, wherein the MFR measured at 190°C and 21.6 kg according to ISO 1133 is 21 Ratio MFR to MFR2 measured according to ISO 1133 at 190°C and 2.16 kg 21 / MFR2 is in the range of 22 to 70, preferably 24 to 55, more preferably 25 to 40.

4. The metallocene-catalyzed multimodal ethylene-1-butene random copolymer according to any one of claims 1 to 3, wherein the total amount of 1-butene is in the range of 5.0 to 15 wt%, preferably 8.0 to 10 wt%, based on the multimodal copolymer.

5. The metallocene-catalyzed multimodal ethylene-1-butene random copolymer according to any one of claims 1 to 4, wherein the copolymer has an amount of isolated 1-butene comonomer units (EBE%) of 97.5 to 100%.

6. The metallocene-catalyzed multimodal ethylene-1-butene random copolymer according to any one of claims 1 to 5, wherein the copolymer comprises (A) a lower molecular weight ethylene-1-butene copolymer component, and (B) A higher molecular weight ethylene-1-butene copolymer component.

7. The metallocene-catalyzed multimodal ethylene-1-butene random copolymer according to claim 6, wherein - the ethylene-1-butene copolymer component (A) has an MFR2 of 2.0 to 300 g / 10 min, preferably 3.2 to 40 g / 10 min, measured according to ISO 1133 at 190° C. and 2.16 kg; and - The ethylene-1-butene copolymer component (B) has an MFR2 of 0.001 g / 10 min to 1.5 g / 10 min, preferably 0.01 g / 10 min to 1.5 g / 10 min, measured according to ISO 1133 at 190°C and 2.16 kg.

8. The metallocene-catalyzed multimodal ethylene-1-butene random copolymer according to claim 6 or 7, wherein the ethylene-1-butene copolymer component (A) is present in an amount of 30 to 70 wt%, based on the total weight of the multimodal copolymer, and the ethylene-1-butene copolymer component (B) is present in an amount of 70 to 30 wt%, based on the total weight of the multimodal copolymer.

9. The metallocene-catalyzed multimodal ethylene-1-butene random copolymer according to any one of claims 6 or 8, wherein the ethylene-1-butene copolymer component (A) consists of an ethylene polymer fraction (A-1) and an ethylene polymer fraction (A-2).

10. A process for preparing a metallocene-catalyzed multimodal ethylene-1-butene random copolymer as defined in any one of claims 1 to 9, the process comprising: (i) in a first polymerization stage, polymerizing ethylene and 1-butene together in the presence of a metallocene catalyst to produce a first ethylene polymer; (ii) polymerizing ethylene together with 1-butene in the presence of the catalyst and the first ethylene polymer in a second polymerization stage to prepare an ethylene polymer mixture comprising the first ethylene polymer and a second ethylene polymer; and (iii) in a third polymerization stage, polymerizing ethylene together with 1-butene in the presence of said catalyst and said ethylene polymer mixture to prepare said multimodal ethylene-1-butene random copolymer.

11. A composition comprising a metallocene-catalyzed multimodal ethylene-1-butene random copolymer as defined in any one of claims 1 to 9 and 5 to 30 wt% of low density polyethylene (LDPE), relative to the total weight of the composition.

12. A film comprising a metallocene-catalyzed multimodal ethylene-1-butene random copolymer as defined in any one of claims 1 to 9 or a composition as defined in claim 11.

13. The film according to claim 12, wherein the film is characterized by a seal initiation temperature below 95°C measured as described in the experimental part on a blown film having a thickness of 40 μm.

14. The film of claim 12 or 13, wherein the film is characterized by a dart drop impact strength (DDI) determined according to ISO 7765-1: 1988 / Method A on a 40 μm single layer test blown film of at least 200 g.

15. An article, preferably a packaging article, comprising the film according to any one of claims 12 to 14.

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