Multimodal Ethylene Copolymers

Abstract

The present invention relates to a novel multimodal ethylene copolymer (P), to the use of said copolymer in film applications and to films comprising said copolymer according to the invention.

Description

Technical Field

[0001] The present invention relates to a novel multimodal ethylene copolymer, to the use of said copolymer in film applications and to films comprising said copolymer of the present invention. Background Art

[0002] Unimodal polyethylene (PE) polymers, such as SSC products, are often used in film applications. For example, unimodal PE polymers have good optical properties, such as low haze, but melt processing of such polymers is not satisfactory from a production point of view and may also lead to quality issues in the final product. Multimodal PE polymers with two or more different polymer components are better processed, but melt homogenization of multimodal PE, for example, may be problematic, leading to an inhomogeneous final product, such as a high gel content in the final product.

[0003] Seal initiation temperature is a critical property of PE films, especially in combination with mechanical properties and ease of converting.

[0004] Different metallocene unimodal PE materials can be found on the market, in which the melting temperature decreases with increasing density, which is a result of the decreasing crystallinity content. Therefore, in these materials, the seal initiation temperature also decreases with decreasing density, thus maintaining a narrow sealing processing window, which can be roughly defined as the difference between the seal initiation temperature and the melting temperature (Tm-SIT).

[0005] Furthermore, reducing the density of metallocene PE materials can also have an adverse effect on other properties (e.g., hardness). These drawbacks are strictly related to the thermodynamic behavior of unimodal PE materials, where it is not possible to broaden the melting window or introduce specific comonomers into specific parts of the molecular weight distribution.

[0006] EP 1472298 A to Borealis discloses a multimodal PE polymer composition having two different comonomers. The multimodal polyethylene polymer is polymerized in the presence of a metallocene catalyst. The Examples disclose a multimodal PE polymer having two polymer components, for example, different types of comonomers.

[0007] This publication appears to define the melt flow ratio (MFR) of the final multimodal PE polymer as 21 / MFR2(FRR 21 / 2 ), but the melt flow ratio of the exemplified polymers varies in the range of 38 to 55. EP 1472298 does not mention any sealing properties of the final multimodal polyethylene polymer.

[0008] Borealis' WO 2016083208 further discloses a metallocene-catalyzed multimodal polyethylene polymer composition consisting of ethylene polymer components (A) and (B). Such polymer compositions described in WO 2016083208 are said to have excellent sealing properties, such as having a lower hot stick temperature at maximum hot stick force and providing seal initiation even at low temperatures. The multimodal PE preferably has a ratio of [the amount (mol%) of α-olefin comonomers having 4-10 carbon atoms present in the ethylene polymer component (A)] to [the amount (mol%) of at least two α-olefin comonomers having 4-10 carbon atoms in the final multimodal ethylene polymer (a)] of 0.2-0.6, preferably 0.24-0.5. The total comonomer content of the polymer according to the embodiment of the present invention is 2.0-2.9 mol%.

[0009] No value is given for the seal initiation temperature.

[0010] Therefore, there is a continuous need to find multimodal PE polymers with further improved sealing properties, ie very low sealing initiation temperature (SIT) and a broad sealing window, ie high values ​​of Tm-SIT. Summary of the invention

[0011] Based on this, the present invention relates to a multimodal ethylene copolymer (P) comprising

[0012] a) an ethylene polymer (A) having an MFR2 of 1-50 g / 10 min (190°C, 2.16 kg, ISO 1133) and a comonomer content in the range of 0.05 mol% to less than 1.0 mol%, wherein the comonomer is selected from C4-C 12 α-olefins; and

[0013] b) an ethylene copolymer (B) having a comonomer content in the range of 5.6 mol% to 10.0 mol%, wherein the comonomer is selected from C4 to C 12 of α-olefins.

[0014] wherein the comonomer of the ethylene copolymer (B) is different from the comonomer of the ethylene copolymer (A), and wherein further

[0015] (i) the total comonomer content of the multimodal ethylene copolymer (P) is in the range of 3.2 mol% to 5.7 mol%, and

[0016] (ii) The weight ratio of the ethylene copolymer (A) to the ethylene copolymer (B) is in the range of 25 / 75 to 60 / 40 or less.

[0017] The term "multimodal" in the context of ethylene polymer (P) refers to the multimodality, ie the differences between, in terms of the comonomer types and comonomer contents present in the ethylene polymer components (A) and (B).

[0018] Furthermore, the multimodal ethylene polymer (P) may be further multimodal with respect to the melt flow rate (MFR) of the ethylene polymer components (A) and (B), ie the ethylene polymer components (A) and (B) have different MFR values ​​and / or densities.

[0019] When mentioned together, the ethylene polymer component (A) and the ethylene polymer component (B) are also referred to as "ethylene polymer components (A) and (B)".

[0020] Multimodal ethylene copolymers (P) are also referred to as "ethylene copolymers (P)" or "ethylene polymers (P)".

[0021] Surprisingly, the ethylene copolymer (P) of the present invention provides improved sealing properties, such as low seal initiation temperature (SIT) and a broad sealing window.

[0022] The present invention also relates to a film comprising at least one layer comprising an ethylene copolymer (P). The film may be a monolayer film comprising an ethylene copolymer (P) or a multilayer film, wherein at least one layer comprises an ethylene copolymer (P). The terms "monolayer film" and "multilayer film" have well-known meanings in the art.

[0023] The following preferred embodiments, properties and groupings of the ethylene copolymer (P), its ethylene polymer components (A) and (B) and films (including preferred ranges thereof) of the present invention are independently generalizable such that they can be used in any order or combination to further define the preferred embodiments of the ethylene copolymer (P) and articles (individually films) of the present invention.

[0024] Multimodal ethylene copolymer (P) and ethylene polymer component (A) and ethylene polymer component (B)

[0025] As mentioned above, the ethylene polymer (P) is referred to herein as "multimodal" because the ethylene polymer component (A) and the ethylene polymer component (B) have different comonomer types and different comonomer contents present in the ethylene polymer components (A) and (B).

[0026] The term "multi" includes "bimodal" compositions consisting of two components which differ in the type and amount of comonomer present in the ethylene polymer components (A) and (B).

[0027] The multimodal ethylene copolymer (P) comprises at least two comonomers having 4 to 12 carbon atoms, preferably monomers having 4 to 10 carbon atoms, more preferably selected from 1-butene, 1-hexene and 1-octene, especially 1-butene and 1-hexene.

[0028] Preferably, the α-olefin comonomer having 4 to 12 carbon atoms in the ethylene polymer component (A) is 1-butene, and the α-olefin comonomer having 4 to 12 carbon atoms in the ethylene polymer component (B) is 1-hexene.

[0029] Preferably, the ratio of [the amount (mol%) of α-olefin comonomers having 4 to 12 carbon atoms present in the ethylene polymer component (A)] to [the amount (mol%) of two α-olefin comonomers having 4 to 12 carbon atoms in the final multimodal ethylene copolymer (P)] is 0.05-0.20, preferably 0.08-0.17.

[0030] The comonomer content of components (A) and (B) can be measured, or, in a preferred case, one of the components is prepared first, followed by the preparation of the other component in the presence of the first component in a so-called multi-stage process, and then the comonomer content of the first prepared 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:

[0031] Comonomer content in component B (mol%) = (comonomer content in final product (mol%) - (weight fraction of component A × comonomer content in component A (mol%)) / (weight fraction of component B)

[0032] Preferably, the content (mol %) of comonomers having 4 to 12 carbon atoms, preferably 4 to 12 carbon atoms, more preferably selected from 1-butene, 1-hexene and 1-octene, especially 1-butene, present in the ethylene polymer component (A) is from 0.05 mol % to less than 1.0 mol %, more preferably 0.10-0.90 mol %, even more preferably 0.15-0.80 mol %, still more preferably 0.20-0.60 mol %.

[0033] In one embodiment, the content (mol%) of α-olefin comonomer having 4 to 12 carbon atoms, preferably 4 to 12 carbon atoms, more preferably selected from 1-butene, 1-hexene and 1-octene, especially 1-hexene, present in the ethylene polymer component (B) is 5.6 to 10.0 mol%, preferably 5.8 to 9.5 mol%, more preferably 6.0 to 9.0 mol%, and even more preferably 6.0 to 8.5 mol%.

[0034] The total amount of comonomers present in the multimodal ethylene copolymer (P) is 3.2 to 5.7 mol%, preferably 3.3 to 5.2 mol%, more preferably 3.5 to 5.0 mol%.

[0035] The specific multimodality, i.e. the difference in comonomer type and comonomer content between the ethylene polymer component (A) and the ethylene polymer component (B), contributes to highly favorable sealing properties, such as excellent sealing initiation temperature at very low temperature and a wide sealing window.

[0036] In addition, ethylene polymer component (A) and ethylene polymer component (B) can be prepared under different polymerization conditions, thereby producing different melt flow rates (MFR, such as MFR2). That is, with respect to the MFR difference of the two ethylene polymer components (A) and (B), the polymer composition is also multimodal.

[0037] Therefore, the term "multi" also includes "bimodal" compositions, consisting of two components having the stated difference in MFR.

[0038] The MFR2 (190°C, 2.16 kg, ISO 1133) of the ethylene polymer component (A) is in the range of 1.0-50.0 g / 10 min, preferably in the range of 1.0-40.0, more preferably in the range of 1.0-30.0, even more preferably in the range of 2.0-20.0, and more preferably in the range of 2.0-15.0, still more preferably in the range of 2.0-10.0 g / 10 min, for example 2.5-7.0 g / 10 min.

[0039] The MFR2 (190°C, 2.16 kg, ISO 1133) of the multimodal ethylene copolymer (P) is in the range of 0.5-7.0, preferably 0.8-5.0 g / 10 min, more preferably 1.0-4.0 g / 10 min, still more preferably 1.2-3.5 g / 10 min.

[0040] If the MFR2 of an ethylene polymer component (e.g. component (B)) cannot be measured because it cannot be separated from the mixture of ethylene polymer components (A) and (B), then it can be determined using the so-called equation( Polymer Processing Association, Europe / Africa Regional Meeting, Gothenburg, Sweden, August 19-21, 1997) to calculate (MI2 as follows).

[0041]

[0042] According to the In the equation (Formula 3), a=5.2 and b=0.7 of MFR2. In addition, w is the weight fraction of other ethylene polymer components (e.g., component (A)) having a higher MFR. Therefore, the ethylene polymer component (A) can be regarded as component 1 and the ethylene polymer component (B) can be regarded as component 2. b is the MFR2 of the final ethylene polymer (P). b ) is known, the MFR2 (MI2) of the ethylene polymer component (B) can be obtained from equation 1.

[0043] Even more preferably, the multimodal ethylene copolymer (P) is further multimodal with respect to the density difference between the ethylene polymer component (A) and the ethylene polymer component (B). Preferably, the density of the ethylene polymer component (A) is different from the density of the ethylene polymer component (B), preferably the density of the ethylene polymer component (A) is higher than the density of the ethylene polymer component (B), further preferably at least 41 kg / m higher. 3 , even more preferably higher than 42kg / m 3 More preferably, the density of the ethylene polymer component (A) is in the range of 925-950, preferably 930-945 kg / m 3 and / or the density of the ethylene polymer component (B) is in the range of 880-915, preferably in the range of 885-913 kg / m 3 In the range of 885-905kg / m 3 .

[0044] The multimodal ethylene copolymer (P) is preferably a linear low density polyethylene (LLDPE), which has a well-known meaning in the art. Even more preferably, the multimodal ethylene copolymer (P) has a density in the range of 905-920, preferably 906-918 kg / m 3 .

[0045] More preferably, the multimodal ethylene copolymer (P) is multimodal, i.e. has differences, at least in MFR2, comonomer type and comonomer content (mol %), and is multimodal, i.e. has differences in the density of the ethylene polymer component (A) and the ethylene polymer component (B), as defined above, below or in the claims including any preferred ranges or embodiments of the ethylene polymer (P).

[0046] Most preferred is the ethylene polymer (P) of the present invention, as defined above, below or in the claims, comprising, preferably consisting of, an ethylene polymer component (A) and an ethylene polymer component (B), wherein

[0047] - the MFR2 (190°C, 2.16 kg, ISO 1133) of the ethylene polymer component (A) is in the range of 1.0-50.0 g / 10 min, preferably in the range of 1.0-40.0, more preferably in the range of 1.0-30.0, even more preferably in the range of 2.0-20.0, but more preferably in the range of 2.0-15.0, yet more preferably in the range of 2.0-10.0 g / 10 min, e.g. 2.5-5.0 g / 10 min;

[0048] - more preferably, the ratio of the MFR2 (190°C, 2.16 kg, ISO 1133) of the ethylene polymer component (A) to the MFR2 (190°C, 2.16 kg, ISO 1133) of the final multimodal ethylene copolymer (P) is between 0.5 and 30, preferably between 0.6 and 20, more preferably between 0.7 and 10, even more preferably between 0.8 and 5.0, but more preferably between 0.9 and 3.0;

[0049] and among them

[0050] - the ethylene polymer component (A) has a different comonomer than the ethylene polymer (B);

[0051] - more preferably, the ratio of [amount (mol%) of α-olefin comonomer having 4 to 12 carbon atoms present in the ethylene polymer component (A)] to [amount (mol%) of two α-olefin comonomers having 4 to 12 carbon atoms in the final multimodal ethylene copolymer (P)] is 0.05 to 0.20, preferably 0.08 to 0.17;

[0052] - even more preferably, wherein the α-olefin comonomer having 4 to 10 carbon atoms in the ethylene polymer component (A) is 1-butene and the α-olefin comonomer having 4 to 10 carbon atoms in the ethylene polymer component (B) is 1-hexene;

[0053] And among them

[0054] - the density of the ethylene polymer component (A) is different from the density of the ethylene polymer component (B), preferably higher

[0055] More preferably, the density of the multimodal ethylene copolymer (P) is in the range of 905-920, preferably 906-918 kg / m 3 .

[0056] Even more preferably, the density of the ethylene polymer component (A) is in the range of 925-950 kg / m 3 , the preferred range is 930-945kg / m 3 .

[0057] In one embodiment, the multimodal ethylene copolymer (P) has a Mw / Mn between 2.3 and 4.8, preferably between 2.5 and 4.6, further preferably between 2.8 and 4.4, such as 3.0-4.3.

[0058] The melting temperature (Tm) of the ethylene copolymer (P) measured according to ISO 11357-3 is preferably at least 115.0° C., more preferably at least 120° C. Therefore, it is particularly appreciated that the melting temperature (Tm) of the ethylene copolymer (P) measured according to ISO 11357-3 is in the range of 117° C. to 133° C., more preferably in the range of 120° C. to 130° C.

[0059] In another embodiment, the multimodal ethylene copolymer (P) has a seal initiation temperature (SIT), determined as described in the experimental part, between 55°C and 90°C, preferably between 60°C and 88°C, further preferably between 62°C and 86°C, more preferably between 63°C and 84°C.

[0060] In another embodiment, the multimodal ethylene copolymer (P) may have a wide sealing window, i.e. the difference between the melting temperature (Tm) and the sealing initiation temperature (SIT), determined as described in the experimental part, Tm-SIT, of at least 37°C, preferably at least 39°C.

[0061] The multimodal ethylene copolymer (P) comprises an ethylene polymer component (A) in an amount of 25.0-60.0 wt%, preferably 32.0-50.0 wt%, more preferably 35.0-48.0 wt%, and an ethylene polymer component (B) in an amount of 40.0-75.0 wt%, preferably 50.0-68.0 wt%, more preferably 52.0-65.0 wt%, based on the total amount (100 wt%) of the ethylene polymer (P). Most preferably, the ethylene polymer (P) consists of the ethylene polymer components (A) and (B) as the only polymer components. Thus, the ratio between the ethylene polymer component (A) and the ethylene polymer component (B) is (25-75):(60-40), preferably (32-68):(50-50), more preferably (35-65):(48-52).

[0062] Ethylene polymer (P) may contain further polymer components and optional additives and / or fillers. If ethylene polymer (P) contains further polymer components, then, based on the combined amount of ethylene polymer (P) and other polymer components, the content of the further polymer components typically varies between 3.0 and 20.0 wt%.

[0063] Optional additives and fillers and their amounts are conventional in the film application field. Examples of these additives include antioxidants, process stabilizers, UV stabilizers, pigments, fillers, antistatic additives, anti-blocking agents, nucleating agents, acid scavengers and polymer processing agents (PPAs).

[0064] It is understood that any additive and / or filler can be optionally added to a so-called masterbatch, which comprises the respective additive and a carrier polymer. In this case, the carrier polymer is not calculated as a polymer component of the ethylene polymer (P), but as the amount of the respective additive, based on the total amount (100 wt %) of the polymer composition.

[0065] It should be noted here that the ethylene polymer (P) may optionally include a prepolymer component, whose content is up to 20.0 wt%, which has a well-known meaning in the art. In this case, the prepolymer component is calculated into one of the ethylene polymer components (A) or (B), preferably into the amount of the ethylene polymer component (A) based on the total amount of the ethylene polymer (P).

[0066] The multimodal ethylene copolymer (P) is preferably prepared using a coordination catalyst. More preferably, the ethylene polymer components (A) and (B) of the ethylene polymer (P) are preferably prepared using a single-site catalyst, which includes metallocene catalysts and non-metallocene catalysts, which terms have well-known meanings in the art. The term "single-site catalyst" refers herein to a catalytically active metallocene compound or complex in combination with a cocatalyst. The metallocene compound or complex is also referred to herein as an organometallic compound (C).

[0067] The organometallic compound (C) comprises a transition metal (M) of Groups 3 to 10 of the Periodic Table of Elements (IUPAC 2007) or an actinide or lanthanide.

[0068] 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 includes metal compounds of Groups 3-10, such as Groups 3-7, or Groups 3-6, such as Groups 4-6, of the Periodic Table of the Elements (IUPAC 2007), as well as lanthanides or actinides.

[0069] In one embodiment, the organometallic compound (C) has the following formula (I):

[0070] (L) m R n MX q (I)

[0071] in

[0072] "M" is a transition metal (M) of Groups 3-10 of the Periodic Table of the Elements (IUPAC 2007),

[0073] Each "X" is independently a monoanionic ligand, such as a sigma-ligand,

[0074] Each "L" is independently an organic ligand coordinated to the transition metal "M",

[0075] "R" is a bridging group connecting the organic ligand (L),

[0076] "m" is 1, 2 or 3, preferably 2

[0077] "n" is 0, 1 or 2, preferably 0 or 1,

[0078] "q" is 1, 2 or 3, preferably 2, and

[0079] m+q equals the valence state of the transition metal (M).

[0080] "M" is preferably selected from the group consisting of zirconium (Zr), hafnium (Hf) or titanium (Ti), more preferably selected from the group consisting of zirconium (Zr) and hafnium (Hf). "X" is preferably halogen, most preferably Cl.

[0081] Most preferably, the organometallic compound (C) is a metallocene complex comprising a transition metal compound as defined above, which contains a cyclopentadienyl, indenyl or fluorenyl ligand as a substituent "L". In addition, the ligand "L" may have one or more substituents, such as alkyl, aryl, aralkyl, alkylaryl, silicon, siloxy, alkoxy or other heteroatom groups. Suitable metallocene catalysts are known in the art and are disclosed in WO-A-95 / 12622, WO-A-96 / 32423, WO-A-97 / 28170, WO-A-98 / 32776, WO-A-99 / 61489, WO-A-03 / 010208, WO-A-03 / 051934, WO-A-03 / 051514, WO-A-2004 / 085499, EP-A-1752462 and EP-A-1739103, among others.

[0082] In one embodiment of the present invention, the metallocene complex is bis(1-methyl-3-n-butylcyclopentadienyl)zirconium(IV) chloride.

[0083] In another embodiment, the organometallic compound (C) has the following formula (II):

[0084]

[0085] wherein each X is independently a halogen atom, a C1-6-alkyl group, a C1-6-alkoxy group, a phenyl group or a benzyl group;

[0086] Each Het is independently a monocyclic heteroaryl containing at least one heteroatom selected from O or S;

[0087] L is -R'2Si-, wherein each R' is independently a C1-20 hydrocarbon group or a C1-10 alkyl group substituted with an alkoxy group having 1 to 10 carbon atoms;

[0088] M is Ti, Zr or Hf;

[0089] Each R1 is the same or different and is C1-6 alkyl or C1-6 alkoxy;

[0090] Each n is 1-2;

[0091] Each R2 is the same or different and is a C1-6 alkyl group, a C1-6 alkoxy group or a -Si(R)3 group;

[0092] Each R is C1-10 alkyl or phenyl optionally substituted with 1-3 C1-6 alkyl groups; and

[0093] Each p is 0-1.

[0094] Preferably, the compound of formula (II) has the structure

[0095]

[0096] wherein each X is independently a halogen atom, a C1-6-alkyl group, a C1-6-alkoxy group, a phenyl group or a benzyl group;

[0097] L is Me2Si-;

[0098] Each R1 is the same or different and is C1-6 alkyl, such as methyl or t-Bu;

[0099] Each n is 1-2;

[0100] R2 is an alkyl group of -Si(R)3; each p is 1;

[0101] Each R is a C1-6 alkyl group or a phenyl group.

[0102] Highly preferred complexes of formula (II) are

[0103]

[0104]

[0105] The most preferred single-site catalyst is a metallocene catalyst, i.e. a catalytically active metallocene complex as defined above, together with a cocatalyst also referred to as an activator. Suitable activators are metal alkyl compounds known in the art, in particular aluminum alkyl compounds. Particularly suitable activators for use with metallocene catalysts are alkylaluminum oxides, such as methylaluminum oxide (MAO), tetraisobutylaluminum oxide (TIBAO) or hexaisobutylaluminum oxide (HIBAO).

[0106] More preferably, the ethylene polymer components (A) and (B) of the ethylene polymer (P) are prepared using, ie in the presence of, the same metallocene catalyst.

[0107] Multimodal ethylene polymer (P) can be prepared in any suitable polymerization process known in the art.Ethylene polymer component (A) is preferably prepared in the first polymerization zone, and ethylene polymer component (B) is prepared in the second polymerization zone.The first polymerization zone and the second polymerization zone can be connected in any order, and i.e. the first polymerization zone can precede the second polymerization zone, or the second polymerization zone can precede the first polymerization zone, or the polymerization zones can be connected in parallel.However, it is preferred to operate the polymerization zone in cascade mode.The polymerization zone can be operated under slurry, solution or gas phase conditions or their combination.The suitable process comprising cascade slurry and gas phase polymerization stage is disclosed in files such as WO-A-92 / 12182 and WO-A-96 / 18662.

[0108] Before introducing the polymer into a subsequent polymerization stage, it is generally preferred to remove the reactants of the previous polymerization stage from the polymer. This is preferably done when transferring the polymer from one polymerization stage to another.

[0109] The catalyst may be transferred to the polymerization zone by any means known in the art. For example, the catalyst may be suspended in a diluent and maintained as a homogeneous slurry, the catalyst may be mixed with a viscous mixture of grease and the resulting paste may be introduced into the polymerization zone, or the catalyst may be allowed to settle and a portion of the catalyst slurry thus obtained may be introduced into the polymerization zone.

[0110] The polymerization in the first polymerization zone, preferably the polymerization of the ethylene polymer component (A), is preferably carried out in a slurry. The polymer particles formed during the polymerization are then suspended in a fluid hydrocarbon together with the catalyst broken up and dispersed in the particles. The slurry is stirred to transfer the reactants from the fluid to the particles.

[0111] The polymerization is usually carried out in an inert diluent, usually a hydrocarbon diluent, such as methane, ethane, propane, n-butane, isobutane, pentane, hexane, heptane, octane, etc., or a mixture thereof. Preferably, the diluent is a low boiling hydrocarbon having 1 to 4 carbon atoms or a mixture of such hydrocarbons, and the preferred diluent is propane.

[0112] The ethylene content of the fluid phase of the slurry may be 2 to about 50 mol %, preferably about 2 to about 20 mol %, and particularly about 3 to about 12 mol %.

[0113] The temperature in the slurry polymerization is generally 50-115° C., preferably 60-110° C., in particular 70-100° C. The pressure is 1-150 bar, preferably 10-100 bar.

[0114] The slurry polymerization can be carried out in any known reactor for slurry polymerization. Such reactors include continuous stirred tank reactors and circulation reactors. It is particularly preferred to carry out the polymerization in a circulation reactor. In such a reactor, the slurry is circulated at high speed along a closed pipeline by using a circulation pump. Circulation reactors are well known in the art, and examples are given in, for example, US-A-4582816, US-A-3405109, US-A-3324093, EP-A-479186 and US-A-5391654.

[0115] Sometimes it is advantageous to carry out the slurry polymerization above the critical temperature and pressure of the fluid mixture. Such an operation is described in US-A-5391654. In such an operation, the temperature is generally 85-110°C, preferably 90-105°C, and the pressure is 40-150 bar, preferably 50-100 bar.

[0116] The slurry may be withdrawn from the reactor continuously or intermittently. A preferred intermittent extraction method is to use a settling tank, wherein the slurry is allowed to concentrate before a batch of concentrated slurry is extracted from the reactor. Continuous extraction is advantageously combined with a suitable concentration method, such as the methods disclosed in EP-A-1310295 and EP-A-1591460.

[0117] Hydrogen can be fed into the reactor to control the molecular weight of the polymer, as is known in the art. In addition, one or more alpha-olefin comonomers are added to the reactor, for example, to control the density of the polymer product. The actual amount of such hydrogen and comonomer added depends on the catalyst used and the desired melt index (or molecular weight) and density (or comonomer content) of the polymer produced.

[0118] The polymerization in the second polymerization zone, preferably the polymerization of the ethylene polymer component (B), is preferably carried out in gas phase, preferably in a fluidized bed reactor, in a fast fluidized bed reactor or in a settled bed reactor or in any combination of these. The polymerization in the second polymerization zone is more preferably carried out in a fluidized bed gas phase reactor, wherein ethylene and at least one comonomer are polymerized in the presence of a polymerization catalyst, preferably in the presence of a reaction mixture comprising the ethylene polymer component (A) from the first polymerization zone, in an upwardly moving gas stream. The reactor typically comprises a fluidized bed comprising growing polymer particles containing an active catalyst located above a fluidized screen.

[0119] The polymer bed is fluidized with the help of a fluidizing gas, which includes the olefin monomer, the final copolymer, the final chain growth controller or chain transfer agent, such as hydrogen, and the final inert gas. The fluidizing gas is introduced into the inlet chamber at the bottom of the reactor. One or more of the above components can be continuously added to the fluidizing gas to compensate for losses caused by the reaction or product extraction, etc.

[0120] The fluidizing gas is passed through the fluidized bed. The superficial velocity of the fluidizing gas must be higher than the minimum fluidizing velocity of the particles contained in the fluidized bed, otherwise no fluidization will occur. On the other hand, the velocity of the gas should be lower than the starting velocity for pneumatic transport, otherwise the entire bed will be entrained by the fluidizing gas.

[0121] When the fluidizing gas contacts the bed containing the active catalyst, the reactive components in the gas, such as monomers and chain transfer agents, react in the presence of the catalyst to produce polymer products. At the same time, the gas is heated by the heat of reaction.

[0122] Unreacted fluidizing gas is discharged from the top of the reactor and cooled in a heat exchanger to remove the heat of reaction. The gas is cooled to a temperature lower than the bed to prevent the bed from being heated by the reaction. It is possible to cool the gas to a temperature at which part of it is condensed. When the droplets enter the reaction zone, they are vaporized. Then, the heat of vaporization helps to eliminate the heat of reaction. This operation is called condensing mode, and its variations are disclosed in WO-A-2007 / 025640, US-A-4543399, EP-A-699213 and WO-A-94 / 25495, etc. A condensing agent can also be added to the circulating gas stream, as disclosed in EP-A-696293. The condensing agent is a non-polymerizable component, such as n-pentane, isopentane, n-butane or isobutane, which is at least partially condensed in a cooler.

[0123] This gas is then compressed and circulated into the inlet chamber of the reactor. Fresh reactants are introduced into the fluidizing gas stream before entering the reactor to compensate for losses due to reaction and product extraction. It is well known to analyze the composition of the fluidizing gas and introduce gas components to keep the composition constant. The actual composition is determined by the desired characteristics of the product and the catalyst used in the polymerization process.

[0124] The catalyst can be introduced into the reactor in various ways (continuously or intermittently). When the gas phase reactor is part of a reactor cascade, the catalyst is usually dispersed in the polymer particles of the previous polymerization stage. The polymer particles can be introduced into the gas phase reactor in the manner disclosed in EP-A-1415999 and WO-A-00 / 26258. In particular, if the preceding reactor is a slurry reactor, it is advantageous to feed the slurry directly into the fluidized bed of the gas phase reactor, as disclosed in EP-A-887379, EP-A-887380, EP-A-887381 and EP-A-991684.

[0125] The polymer product can be extracted from the gas phase reactor continuously or intermittently. A combination of these methods can also be used. WO-A-00 / 29452 and the like disclose a method of continuous extraction. Intermittent extraction is disclosed in US-A-4621952, EP-A-188125, EP-A-250169 and EP-A-579426 and the like.

[0126] If desired, antistatic agents, such as water, ketones, aldehydes and alcohols, may also be introduced into the gas phase reactor. The reactor may also include a mechanical agitator to further promote mixing within the fluidized bed.

[0127] Usually, the operating temperature of the fluidized bed polymerization reactor is between 50-100° C., preferably between 65-90° C. The pressure is preferably between 10-40 bar, preferably between 15-30 bar.

[0128] In the first and second polymerization zones, at least the polymerization of ethylene polymer component (A) and ethylene polymer component (B) can first be subjected to a prepolymerization step. The purpose of the prepolymerization is to polymerize a small amount of polymers onto a catalyst at low temperatures and / or low monomer concentrations. Through prepolymerization, it is possible to improve the performance of the catalyst in the slurry and / or change the characteristics of the final polymer. The prepolymerization step can be carried out in the slurry or in the gas phase. It is preferred to carry out prepolymerization in the slurry, preferably in a circulating reactor. Then, the prepolymerization is preferably carried out in an inert diluent, and the diluent is preferably a low-boiling hydrocarbon with 1 to 4 carbon atoms or a mixture of this hydrocarbon.

[0129] The temperature in the prepolymerization step is usually 0-90°C, preferably 20-80°C, more preferably 40-70°C.

[0130] The pressure is not critical and is generally 1-150 bar, preferably 10-100 bar.

[0131] The catalyst components are preferably all introduced into the prepolymerisation step. Preferably, the reaction product of the prepolymerisation step is subsequently introduced into the first polymerisation zone. It is also preferred that the prepolymer components are calculated as the amount of ethylene polymer component (A), as described above.

[0132] It is within the knowledge of the skilled person to adjust the polymerization conditions of each step as well as the feed flows and residence times in order to obtain the desired multimodal ethylene copolymer (P).

[0133] The multimodal ethylene copolymer (P) comprising at least, preferably only, ethylene polymer components (A) and (B) is obtained from the second polymerization zone, preferably the above-mentioned gas phase reactor, and is then subjected to conventional post-reactor treatment to remove unreacted components.

[0134] Thereafter, typically, the polymer obtained is extruded and pelletized. Extrusion can be carried out in a manner generally known in the art, preferably in a twin screw extruder. An example of a suitable twin screw extruder is a co-rotating twin screw extruder. These are manufactured by Coperion or Nippon Steel Works, etc. Another example is a counter-rotating twin screw extruder. Such extruders are manufactured by Kobe Steel and Nippon Steel Works, etc. Prior to extrusion, as described above, preferably at least a portion of the desired additives are mixed with the polymer. An extruder typically includes a melting zone for melting the polymer and a mixing zone for homogenizing the polymer melt.

[0135] The film of the present invention

[0136] The film of the present invention comprises at least one layer comprising a multimodal ethylene copolymer (P). The film may be a monolayer film comprising a multimodal ethylene copolymer (P) or a multilayer film, wherein at least one layer comprises a multimodal ethylene copolymer (P). The terms "monolayer film" and "multilayer film" have well-known meanings in the art.

[0137] The layers of the monolayer or multilayer film of the present invention may consist of the multimodal ethylene copolymer (P) itself or a mixture of the multimodal ethylene copolymer (P) and other polymers. In the case of a mixture, any other polymer is different from the ethylene polymer (P), preferably a polyolefin. Some of the above-mentioned additives, such as processing aids, can be optionally added to the polymer composition during the film preparation process.

[0138] 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%, and more preferably at least 80 wt% of the multimodal ethylene copolymer (P) of the present invention. Most preferably, said at least one layer of the film of the present invention consists of the multimodal ethylene copolymer (P).

[0139] Thus, the films of the present invention may comprise a single layer (ie a monolayer) or may be multilayer. Multilayer films typically and preferably comprise at least 3 layers.

[0140] The film is preferably prepared by any conventional film extrusion procedure known in the art, including cast film and blown film extrusion. Most preferably, the film is a blown or cast film, particularly a blown film. For example, a blown film is prepared by extruding through an annular die and blowing into a tubular film by forming bubbles, which collapses between pressure rollers after solidification. This film can then be slit, cut or converted (such as a sandwich) as required. Conventional film preparation techniques can be used in this regard. If the preferred blown or cast film is a multilayer film, the layers of film are typically coextruded. The technician will know the appropriate extrusion conditions.

[0141] The resulting film can have any thickness conventional in the art. The thickness of the film is not critical and depends on the end use. Thus, the thickness of the film can be, for example, 300 μm or less, typically 6-200 μm, preferably 10-180 μm, for example 20-150 μm or 20-120 μm. If desired, the polymer of the present invention can be made less than 100 μm thick, for example less than 50 μm. While maintaining good mechanical properties, it is also possible to prepare a film of the present invention having a thickness of even less than 20 μm.

[0142] The present invention preferably relates to blown extruded films. The extrusion coated substrate comprises a substrate and at least one layer of a multimodal ethylene polymer (P) extrudate as defined in the present invention coated on said substrate.

[0143] Furthermore, the present invention also relates to the use of the preparation according to the invention as packaging material, in particular as packaging material for food and / or medical products.

[0144] Determination method

[0145] Unless otherwise stated in the description or in the experimental section, the following methods were used to determine the properties of the polymer compositions and / or any sample preparations thereof specified in the text or in the experimental section.

[0146] Melt flow rate

[0147] The melt flow rate (MFR) is measured according to ISO1133 and is expressed in g / 10min. The MFR is an indicator of the fluidity of the polymer and therefore also reflects the processability of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer. The MFR of polyethylene is measured at 190°C. The MFR can be measured at different loads, such as 2.16kg (MFR2), 5kg (MFR5) or 21.6kg (MFR 21 ).

[0148] density

[0149] The density of the polymer is measured according to ASTM; D792, method B (equilibrium density at 23°C) on compression moulded test specimens prepared according to EN ISO 1872-2 (February 2007) and is expressed in kg / m.

[0150] Molecular weight, molecular weight distribution (Mn, Mw, MWD)--GPC

[0151] A PL 220 (Agilent) GPC equipped with a refractometer (RI), an online four-capillary bridge viscometer (PL-BV400-HT) and a dual light scattering detector with 15° and 90° angles (PL-LS 15 / 90 light scattering detector) was used. Agilent's 3x Olexis and 1x Olexis Guard columns were used as stationary phases, 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg / L of 2,6-di-tert-butyl-4-methylphenol) was used as the mobile phase, the temperature was 160°C, and the flow rate was 1 mL / min. 200 mL of sample solution were injected for each analysis. All samples were prepared by dissolving 8.0-12.0 mg of polymer in 10 mL (160°C) of stabilized TCB (same as mobile phase) and shaking continuously and gently at 160°C for 6 hours for polypropylene and 3 hours for polyethylene. The injected concentration (c 160℃ ) is determined as follows.

[0152]

[0153] Note: 25 (polymer weight) and V 25 (Volume of TCB at 25°C).

[0154] The corresponding detector constant and the delay volume between detectors were determined using a narrow PS standard (MWD = 1.01) with a molar mass of 132900 g / mol and a viscosity of 0.4789 dl / g. The corresponding dn / dc of the PS standard used in TCB is 0.053 cm 3Calculations were performed using Cirrus Multi-Offline SEC-Software Version 3.2 (Agilent).

[0155] The molar mass of each elution slice was calculated by using 15° light scattering angles. Data collection, data processing and calculations were performed using Cirrus Multi SEC-Software Version 3.2. The molecular weight was calculated by the "Use LS 15° Angle" option in the "MW data from sample calculation options subfield slice" in the Cirrus software. The dn / dc used to determine the molecular weight was calculated from the detector constant of the RI detector, the concentration c of the sample and the detector response area of ​​the analyzed sample.

[0156] The molecular weight of each slice is calculated at a low angle according to the method described by C. Jackson and H. G. Barth (C. Jackson and H. G. Barth, "Molecular Weight Sensitive Detectors", in: Handbook of Size Exclusion Chromatography and related techniques, C.-S. Wu, 2nd edition, Marcel Press, New York, 2004, p. 103). For the low molecular weight region and the high molecular weight region, the signal of the LS detector or the RI detector is less, respectively, and the elution amount is linked to the corresponding molecular weight using linear fitting. According to the situation of the sample, the area of ​​the linear fitting is adjusted.

[0157] According to ISO 16014-4:2003 and ASTM D 6474-99, the average molecular weight (Mz, Mw and Mn), molecular weight distribution (MWD) and its breadth are determined by gel permeation chromatography (GPC), wherein the molecular weight distribution (MWD) and its breadth are described by polydispersity index PDI=Mw / Mn (where Mn is the number average molecular weight and Mw is the weight average molecular weight) and calculated using the following formula:

[0158]

[0159]

[0160]

[0161] For a constant elution volume interval ΔV i , where A i and M iis the chromatographic peak slice area and the molecular weight (MW) of the polyolefin determined by GPC-LS.

[0162] Comonomer content: quantification of microstructure by NMR spectroscopy

[0163] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content of the polymers.

[0164] In the molten state, the precipitate was analyzed using a Brucker Advance III 500 NMR spectrometer. 1 H and 13 C was operated at 500.13 and 125.76 MHz, respectively, and the quantitative 13 C{ 1 H} NMR spectra. All spectra were acquired at 150 13 The spectra were recorded using a C-optimized 7 mm magic angle spinning (MAS) probe head, with nitrogen used for all pneumatics. Approximately 200 mg of material was loaded into a 7 mm outer diameter zirconium oxide MAS rotor, which was spun at 4 kHz. This setup was chosen primarily for the high sensitivity required for rapid identification and accurate quantification. Single pulse excitation was used as standard {klimke06, parkinson07, castignolles09}, with short recycle delays using the NOE {pollard04, klimke06} and RS-HEPT decoupling scheme {fillip05, griffin07}. A total of 1024 (1k) transients were acquired for each spectrum.

[0165] Quantification 13 C{ 1 The H} NMR spectra were processed, integrated, and the relevant quantitative properties were determined from the integrated results. All chemical shifts were internally referenced to the bulk methylene signal (δ+) at 30.00 ppm.

[0166] The amount of ethylene was quantified using the integration of the methylene (δ+) sites at 30.00 ppm combined with the number of reported sites for each monomer:

[0167] E=I δ+ + / 2

[0168] Correction for the presence of isolated comonomer units was made based on the number of isolated comonomer units present:

[0169] E total = E + (3*B + 2*H) / 2

[0170] where B and H are defined for their respective comonomers. If continuous and discontinuous blends are present, correction is made in a similar manner.

[0171] Observe the characteristic signal corresponding to the addition of 1-butene and calculate the comonomer fraction, that is, the fraction of 1-butene in the polymer relative to all monomers in the polymer:

[0172] fBtotal=(Btotal / (Etotal+Btotal+Htotal)

[0173] The amount of isolated 1-butene incorporated in the EEBEE sequence was quantified using the integration of the *B2 site at 38.3 ppm combined with the number of reported sites for each comonomer:

[0174] B=I *B2

[0175] The amount of 1-butene added continuously in the EEBBEE sequence was quantified using the integral of the ααB2B2 site at 39.4 ppm combined with the number of reported sites for each comonomer:

[0176] BB=2*IααB2B2

[0177] The amount of discontinuous incorporation of 1-butene in the EEBEBEE sequence was quantified using the integral of the ββB2B2 site at 24.7 ppm combined with the reported number of sites for each comonomer:

[0178] BEB=2*IββB2B2

[0179] Since the *B2 and *βB2B2 sites in isolated (EEBEE) and discontinuously added (EEBEE) 1-butene overlap, respectively, the total amount of isolated 1-butene added was corrected for the amount of discontinuous 1-butene present:

[0180] B=I *B2 -2*I ββB2B2

[0181] The total 1-butene content was calculated from the sum of isolated, continuous and discontinuous 1-butene additions:

[0182] Total B=B+BB+BEB

[0183] The total mole fraction of 1-butene in the polymer is then calculated as:

[0184] fB=(Total B / (Total E+Total B+Total H)

[0185] Observe the characteristic signal corresponding to the addition of 1-hexene and calculate the ratio of 1-hexene in the polymer relative to all monomers in the polymer:

[0186] fHtotal=(Htotal / (Etotal+Btotal+Htotal)

[0187] The amount of isolated 1-hexene incorporated in the EEHEE sequence was quantified using the integration of the *B4 site at 39.9 ppm combined with the reported number of sites for each comonomer:

[0188] H=I *B4

[0189] The amount of 1-hexene added continuously in the EEHHEE sequence was quantified using the integral of the ααB4B4 site at 40.5 ppm combined with the reported number of sites for each comonomer:

[0190] HH=2*IααB4B4

[0191] The amount of 1-hexene added discontinuously in the EEHEHEE sequence was quantified using the integral of the ββB4B4 site at 24.7 ppm combined with the number of reported sites for each comonomer:

[0192] HEH=2*IββB4B4

[0193] The total mole fraction of 1-hexene in the polymer is then calculated as:

[0194] fH=(H total / (E total+B total+H total)

[0195] Calculate the mole percentage of comonomer from the mole fraction:

[0196] B[mol%]=100*fB

[0197] H[mol%]=100*fH

[0198] Calculate the weight percent of comonomer from the mole fraction:

[0199] B[wt%]=100*(fB*56.11) / ((fB*56.11)+(fH*84.16)+((1-(fB+fH)))*28.05))

[0200] H[wt%]=100*(fH*84.16) / ((fB*56.11)+(fH*84.16)+((1-(fB+fH))*28.05))

[0201] References:

[0202] klimke06: Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, HW, Wilhelm, M., Macromol. Chem. Phys. 2006;207:382.

[0203] parkinson07:Parkinson,M.,Klimke,K.,Spiess,H.W.,Wilhelm,M.,Macromol.Chem.Phys.2007;208:2128.

[0204] pollard04:Pollard,M.,Klimke,K.,Graf,R.,Spiess,H.W.,Wilhelm,M.,Sperber,O.,Piel,C.,Kaminsky,W.,Macromolecules 2004;37:813.

[0205] filip05:Filip,X.,Tripon,C.,Filip,C.,J.Mag.Resn.2005,176,239

[0206] griffin07:Griffin,J.M.,Tripon,C.,Samoson,A.,Filip,C.,and Brown,S.P.,Mag.Res.in Chem.200745,S1,S198

[0207] castignolles09:Castignolles,P,Graf,R.,Parkinson,M.,Wilhelm,M.,Gaborieau,M.,Polymer 50(2009)2373

[0208] busico01:Busico,V.,Cipullo,R.,Prog.Polym.Sci.26(2001)443

[0209] busico97:Busico,V,Cipullo,R.,Monaco,G.,Vacatello,M.,Segre,A.L.,Macromoleucles 30(1997)6251

[0210] zhou07:Zhou,Z.,Kuemmerle,R.,Qiu,X.,Redwine,D.,Cong,R.,Taha,A.,Baugh,D.Winniford,B.,J.Mag.Reson.187(2007)225

[0211] busico07: Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128

[0212] resconi00: Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253

[0213] Differential Scanning Calorimetry (DSC)

[0214] The experiments were performed with a TA Instruments Q200 calibrated with Indium, Zinc and Tin according to ISO 11357-3. Approximately 5 mg of material was placed in the pan and the test was carried out at a rate of 10 °C / min with a nitrogen flow of 50 mL / min throughout the experiment, with lower and upper temperatures of -30 °C and 180 °C, respectively. Only the second heating run was considered for the analysis. The melting temperature, Tm, was defined as the temperature of the main peak of the thermogram, while the melting enthalpy (ΔHm) was calculated by integrating between 10 °C and the end of the thermogram (usually Tm+15 °C). The integral of the runs in this range was also calculated.

[0215] Sealing performance:

[0216] Sealing Initiation Temperature (SIT):

[0217] The seal initiation temperature, SIT*, is predicted with the aid of an artificial neural network. The input data is provided by differential scanning calorimetry (DSC).

[0218] Artificial neural networks were trained using Python / TensorFlow / Keras by analyzing at least 21 PE materials with known SIT.

[0219] The lower limit (heat seal initiation temperature (SIT)) refers to the sealing temperature at which a seal strength > 5N is achieved.

[0220] The sealing range was determined on a J&B 3000 universal sealer with a film thickness of 40 μm and further parameters as follows:

[0221] Sample width: 25.4mm

[0222] Sealing pressure: 0.1N / mm 2

[0223] Sealing time: 0.1s

[0224] Cooling time: 99s

[0225] Peeling speed: 10mm / s

[0226] Starting temperature: 50℃

[0227] End temperature: 150℃

[0228] Increase: 5℃

[0229] The specimens were sealed A to A at each seal bar temperature and the seal strength (force) was determined at each step.

[0230] Determine the temperature at which the seal strength reaches 5N.

[0231] At least 17 materials (polyethylene copolymers) were used for training, with SITs ranging from 75°C to 113°C, which were generally uniform. At least four materials were used for network testing, with two having SITs of about 92°C, one at 85°C, and one at 68°C.

[0232] The input data are the melting temperature and melting enthalpy of the material measured by DSC, plus 6 parameters from the integration of the thermogram run. These parameters are selected as the temperatures at 14.8%, 17.4% and 35.8% melting and the melting enthalpy (in J / g) at 21.8%, 55.2% and 18.2%. The integration of the thermogram starts at 25°C. The input data are normalized in each column in the range [0, 1].

[0233] The ANN was trained repeatedly until the mean absolute error (MAE) was below 0.00151 for the training input and below 0.00349 for the validation input, ensuring that the prediction accuracy of the 68 test points of the test set was <1 above the prediction. The validation split used was 0.15, the number of epochs was 400, but early stopping was used, i.e. only the network with the best MAE of the training set was kept, the tolerance value was 150, the batch size was 1, the "batch size optimizer", the loss was MSE (mean squared error), and the metrics were MSE and MAE. The network consisted of three fully connected layers, where the first two layers had 32 and 65 nodes respectively, with relu activation function, and the last layer was a single layer of linear activation function. Noise can be added to the input layer for normalization purposes, for example with an amplitude of 0.02. Noise can also be added to the output layer, also with an amplitude of 0.02, to help the network generalize to measure accuracy. Training of a suitable network may require 100,000 repetitions to succeed.

[0234] Preparation of thin film samples

[0235] Test films with a thickness of 40 μm consisting of the inventive multimodal ethylene copolymer (P) and the respective comparative or reference polymer composition were produced using a Collin 30 laboratory scale monolayer blown film line.

[0236] The screw diameter of the production line is 25 millimeters (mm), the length-to-diameter ratio L / D is 25, the die diameter is 60 mm, and the die gap is 1.5 mm. The film samples were prepared at 190°C, with an average thickness of 40 μm, a blow ratio of 1:3, and a frost line distance of 120 mm. The melting temperature is 190°C.

[0237] Experimental Section

[0238] Catalyst Cat 1 preparation

[0239] Two-step method for catalyst preparation

[0240] Step A: Preparation of active carrier (SiO2 / MAO)

[0241] Under nitrogen, 20 g of pretreated silica and 100 mL of dry toluene were placed in a multi-necked glass reactor equipped with a mechanical stirrer. Gentle stirring was started and the slurry was cooled to -10 to 0°C. Methylaluminoxane solution (175 mmol Al, 30 wt% MAO toluene solution) was then slowly added over 30 minutes while keeping the reaction mixture temperature below 25°C. The slurry was then further stirred at room temperature for 30 minutes. After that, the stirred reaction mixture was heated to 90°C over 20 minutes and continued to stir at this temperature for 2 hours. The slurry was then precipitated at 90°C for 15 minutes and the hot supernatant was drawn off. 100 mL of dry toluene was added and stirred at 90°C for 30 minutes to wash the SiO2 / MAO carrier. The carrier was precipitated and the supernatant was siphoned off. The method for washing the carrier for the second time was the same as above, except that the washing temperature was between 50-70°C. The method for washing the carrier for the third time was the same as above, except that 100 mL of dry n-heptane was used instead of toluene and the washing was carried out at room temperature. The supernatant was siphoned off and the activated SiO2 / MAO support was first dried in a nitrogen stream at 60°C until no free liquid was observed and then thoroughly dried in a vacuum at 60°C for at least 2 hours.

[0242] Step B: Preparation of primary catalyst

[0243] 35 μmol of Rac-dimethylsilane bis[2-(5-trimethylsilylfuran-2-yl)-4,5-dimethylcyclopentadiene-1-yl]zirconium dichloride was dissolved in a mixture of 1 mL of dry toluene and MAO solution (1.05 mmol Al, 30 wt% MAO toluene solution), and stirred in a small glass bottle at room temperature for 1 hour under a nitrogen atmosphere. Then, under gentle mechanical stirring, the resulting solution was added dropwise to 1 gram of active carrier (SiO2 / MAO) in a glass reactor within 5 minutes. Then, the crude main catalyst was gently mixed at room temperature for 1 hour and then allowed to stand for 17 hours. Then, the main catalyst was vacuum dried at 60°C for 30 minutes.

[0244]

[0245] Cat. Example: Catalyst Cat 2

[0246] As catalyst Cat2, an aluminoxane-containing supported catalyst was used, which contained metallocene bis(1-methyl-3-n-butylcyclopentadienyl)zirconium(IV) chloride and an enhanced catalyst from Grace. Activator technology.

[0247] Polymerization: Inventive Example 1:

[0248] Inventive multimodal polymers of ethylene with 1-butene and 1-hexene comonomers

[0249] All polymerizations were carried out in a stirred autoclave with a volume of 5.3 l. The polymerization process was as follows:

[0250] 800 g of propane were introduced into the evacuated autoclave. 0.12 mmol of triethylaluminum (0.62 mol / 1 heptane solution) was added using an additional 100 g propane stream. 16 g of ethylene and 0.0013 g of hydrogen were added and the reactor was heated to the desired prepolymerization temperature of 60°C.

[0251] The required amount of catalyst was weighed into a steel bottle inside the glove box and suspended in 3 mL of heptane (8 mL if the catalyst was an oil slurry). The vial was then connected to the polymerization autoclave and the suspension was flushed into the reactor with 100 g of propane.

[0252] For the prepolymerization, the reactor was stirred at 60°C for 45 minutes. The pressure was maintained at 20.9 barg by feeding ethylene through a flow meter. The temperature was then increased to 85°C and the required batches of hydrogen and 1-butene were added to the reactor. At the same time, ethylene was fed until the desired polymerization pressure was reached.

[0253] For slurry polymerization, the reactor was stirred at 85°C. The pressure was kept constant by adding ethylene, 1-butene and hydrogen in fixed ratios. After 200 g of ethylene had been consumed, the reaction was stopped by venting and evacuating the reactor.

[0254] For gas phase polymerization, the reactor temperature was set to 75°C. It was refilled with propane until the desired pressure was reached. The required amount of hydrogen and 1-hexene was fed into the reactor. At the same time, ethylene was fed until the reactor pressure reached 20 bar. During the polymerization, the pressure was kept constant by feeding ethylene, 1-hexene and hydrogen in fixed ratios. After the desired amount of ethylene had been consumed, the reaction was stopped by venting the reactor.

[0255] Similar polymerization conditions were used for both catalysts.

[0256] The polymers of Tables 1 and 2 were prepared in a laboratory benchtop reactor apparatus in a two-step polymerization process starting with a slurry step and then polymerizing in the gas phase, varying the molecular weight and the butene and hexene content by appropriate hydrogen and comonomer feeds. The catalyst used in the polymerization process was a metallocene catalyst prepared as described above.

[0257] Table 1: Preparation of Examples

[0258] Example IE1 IE2 IE3 CE1 CE2 catalyst CAT 1 CAT 2 CAT 1 CAT 2 CAT 1 Serum 1-Butene batch [g] 4.5 6.6 4.6 6.6 6.6 <![CDATA[Batch H2]]> [mg] 17 6 17 6 23 pressure [barg] 37.4 36.9 37.4 36.9 39.2 <![CDATA[Continuous feed rate H2 / C2]]> [g / g] <![CDATA[6.8·10 -5 ]]> <![CDATA[6.8·10 -5 ]]> <![CDATA[6.8·10 -5 ]]> <![CDATA[6.8·10 -5 ]]> <![CDATA[6.8·10 -5 ]]> <![CDATA[Continuous feed rate C4 / C2]]> [g / g] 0.018 0.015 0.018 0.015 0.018 <![CDATA[C4 in the polymer]]> [wt%] 1.0 0.7 0.9 1.1 1.4 <![CDATA[C4 in the polymer]]> [mol%] 0.51 0.36 0.44 0.56 0.71 density <![CDATA[[kg / m 3 ]]]> 942 939 942 939 939 <![CDATA[MFR2]]> [g / 10min] 4.0 2.9 4.0 2.9 5.8 GPR Propane partial pressure [barg] 14 14 10 14 10 1-Hexene batch [g] 19.6 29.9 22.5 19.6 22.5 <![CDATA[Batch H2]]> [mg] 0.8 0.8 2.1 0.8 4.1 <![CDATA[Continuous feed of C2H4]]> [g] 220 230 278 220 278 <![CDATA[Continuous feed rate H2 / C2]]> [g / g] <![CDATA[3.9·10 -05 ]]> <![CDATA[3.9·10 -05 ]]> <![CDATA[4.2·10 -05 ]]> <![CDATA[3.9·10 -05 ]]> <![CDATA[6.7·10 -05 ]]> <![CDATA[Continuous feed rate C4 / C2]]> [g / g] 0.27 0.20 0.17 0.13 0.09 <![CDATA[C6 in GPR polymer]]> [wt%] 21.1 18.0 16.8 11.3 10.8 <![CDATA[C6 in GPR polymer]]> [mol%] 8.2 6.8 6.3 4.1 3.9 GPR Medium Density <![CDATA[[kg / m 3 ]]]> 886 897 897 908 912 <![CDATA[MFR2 in GPR]]> [g / 10min] 1.1 3.3 1.0 2.3 3.4 Separation of GPR [wt%] 58 58 61 56 61

[0259] The slurry defines the ethylene copolymer (A); the GPR defines the ethylene copolymer (B).

[0260] C4 is 1-butene; C6 is 1-hexene

[0261] Table 2: Characteristics of the examples

[0262]

[0263] Final definition of multimodal ethylene polymer (P)

[0264] C4 is 1-butene; C4(A) is the butene content in the copolymer (A)

[0265] C6 is 1-hexene

[0266] SIT* is the heat seal initiation temperature

[0267] These polymers have been stabilized with 0.5 wt% Iganox B225.

[0268] The polymers of Table 3 are selected from commercially available resins as additional comparative examples. The main properties of these commercial examples are given in Table 3. In addition, in Table 3, the SIT* of these characteristic commercially available resins is also given.

[0269] Table 3: Properties of commercial examples

[0270]

[0271] C4 is 1-butene, C6 is 1-hexene, C8 is 1-octene

[0272] SIT* is the heat seal initiation temperature

[0273] MFR2 and density are reported and extracted from the technical data sheet for each grade.

[0274] The examples of the present invention show improved / reduced SIT and, in addition, a wider sealing window compared to the comparative examples.

Claims

1. A multimodal ethylene copolymer (P) comprising a) an ethylene polymer (A) having an MFR2 of 1 to 30 g / 10 min at 190°C, 2.16 kg, measured according to ISO 1133, and a comonomer content in the range of 0.05 mol% to less than 1.0 mol%, wherein the comonomer is selected from C4-C 12 α-olefins; and b) an ethylene copolymer (B) having a comonomer content in the range of 5.6 mol% to 10.0 mol%, wherein the monomer is selected from C4-C 12 α-olefins, wherein the monomers of the ethylene copolymer (B) are different from the monomers of the ethylene copolymer (A), and wherein (i) the total comonomer content of the multimodal ethylene copolymer (P) is in the range of 3.2 mol% to 5.7 mol%, and (ii) The weight ratio of the ethylene copolymer (A) to the ethylene copolymer (B) is in the range of 25 / 75 to 60 / 40.

2. The multimodal ethylene copolymer (P) according to claim 1, wherein The MFR2 of the ethylene polymer component (A) measured at 190°C, 2.16 kg according to ISO 1133 is 2.0 to 20.0 g / 10 min.

3. The multimodal ethylene copolymer (P) according to claim 1, wherein The MFR2 of the ethylene polymer component (A) measured at 190°C, 2.16 kg according to ISO 1133 is 2.0 to 10.0 g / 10 min.

4. The multimodal ethylene copolymer (P) according to claim 1, wherein The MFR2 of the multimodal ethylene copolymer (P), measured according to ISO 1133 at 190°C, 2.16 kg, is from 0.5 to 7.0 g / 10 min.

5. The multimodal ethylene copolymer (P) according to claim 1, wherein The MFR2 of the multimodal ethylene copolymer (P), measured according to ISO 1133 at 190°C, 2.16 kg, is 1.2 to 3.5 g / 10 min.

6. The multimodal ethylene copolymer (P) according to claim 1, wherein The ratio of the amount of α-olefin comonomers having 4 to 12 carbon atoms present in the ethylene polymer component (A) to the amount of at least two α-olefin comonomers having 4 to 12 carbon atoms in the final multimodal ethylene copolymer (P) is from 0.05 to 0.20, wherein the units of the amount of α-olefin comonomers having 4 to 12 carbon atoms present in the ethylene polymer component (A) and the amount of at least two α-olefin comonomers having 4 to 12 carbon atoms in the final multimodal ethylene copolymer (P) are both mol%.

7. The multimodal ethylene copolymer (P) according to claim 1, wherein The ratio of the amount of α-olefin comonomers having 4 to 12 carbon atoms present in the ethylene polymer component (A) to the amount of at least two α-olefin comonomers having 4 to 12 carbon atoms in the final multimodal ethylene copolymer (P) is from 0.08 to 0.17, wherein the units of the amount of α-olefin comonomers having 4 to 12 carbon atoms present in the ethylene polymer component (A) and the amount of at least two α-olefin comonomers having 4 to 12 carbon atoms in the final multimodal ethylene copolymer (P) are both mol%.

8. The multimodal ethylene copolymer (P) according to claim 1, wherein The density of the multimodal ethylene copolymer (P) is in the range of 905-920 kg / m 3 .

9. The multimodal ethylene copolymer (P) according to claim 1, wherein The density of the multimodal ethylene copolymer (P) is in the range of 906-918 kg / m 3 .

10. The multimodal ethylene copolymer (P) according to claim 1, wherein The melting temperature Tm of the ethylene copolymer composition (P) measured according to ISO 11357-3 is in the range of 117-133°C.

11. The multimodal ethylene copolymer (P) according to claim 1, wherein The melting temperature Tm of the ethylene copolymer composition (P) measured according to ISO 11357-3 is in the range of 120-130°C.

12. The multimodal ethylene copolymer (P) according to claim 1, wherein The seal initiation temperature (SIT) of the copolymer is between 55°C and 90°C.

13. The multimodal ethylene copolymer (P) according to claim 1, wherein The seal initiation temperature (SIT) of the copolymer is between 63°C and 84°C.

14. The multimodal ethylene copolymer (P) according to claim 1, wherein The difference between the melting temperature (Tm) and the sealing initiation temperature (SIT), Tm-SIT, of the multimodal ethylene copolymer (P) is at least 37°C.

15. The multimodal ethylene copolymer (P) according to claim 1, wherein The difference between the melting temperature (Tm) and the sealing initiation temperature (SIT), Tm-SIT, of the multimodal ethylene copolymer (P) is at least 39°C.

16. The multimodal ethylene copolymer (P) according to claim 1, wherein The Mw / Mn of the multimodal ethylene copolymer (P) is between 2.3 and 4.

8.

17. The multimodal ethylene copolymer (P) according to claim 1, wherein The Mw / Mn of the multimodal ethylene copolymer (P) is between 2.8 and 4.

4.

18. The multimodal ethylene copolymer (P) according to claim 1, wherein The ratio of the MFR2 of the ethylene polymer component (A) measured according to ISO 1133 at 190°C, 2.16 kg to the MFR2 of the final multimodal ethylene copolymer (P) measured according to ISO 1133 at 190°C, 2.16 kg is between 0.5 and 30.

19. The multimodal ethylene copolymer (P) according to claim 1, wherein The ratio of the MFR2 measured at 190°C, 2.16 kg according to ISO 1133 of the ethylene polymer component (A) to the MFR2 measured at 190°C, 2.16 kg according to ISO 1133 of the final multimodal ethylene copolymer (P) is between 0.9 and 3.

0.

20. The multimodal ethylene copolymer (P) according to claim 1, wherein The density of the ethylene polymer component (B) is in the range of 880-915 kg / m 3 .

21. The multimodal ethylene copolymer (P) according to claim 1, wherein The density of the ethylene polymer component (B) is in the range of 885-910 kg / m 3 .

22. The multimodal ethylene copolymer (P) according to claim 1, wherein The multimodal ethylene copolymer (P) is prepared using an organometallic compound (C) of formula (I): (I): (L)mRnMXq(I) in "M" is a transition metal (M) of Groups 3-10 of the Periodic Table of Elements; Each "X" is independently a monoanionic ligand; Each "L" is independently an organic ligand coordinated to the transition metal "M", "R" is a bridging group connecting the L organic ligand, "m" is 1, 2, or 3, "n" is 0, 1, or 2, "q" is 1, 2, or 3, and m+q is equal to the valence state of the transition metal (M) or the organometallic compound (C) of formula II: wherein each X is independently a halogen atom, a C1-6-alkyl group, a C1-6-alkoxy group, a phenyl group or a benzyl group; Each Het is independently a monocyclic heteroaryl containing at least one heteroatom selected from O or S; L is -R'2Si-, wherein each R' is independently a C1-20 hydrocarbon group or a C1-10 alkyl group substituted with an alkoxy group having 1 to 10 carbon atoms; M is Ti, Zr or Hf; Each R1 is the same or different and is C1-6 alkyl or C1-6 alkoxy; Each n is 1-2; Each R2 is the same or different and is a C1-6 alkyl, C1-6 alkoxy or -Si(R)3 group; Each R is C1-10 alkyl substituted by 1-3 C1-6 alkyl groups or unsubstituted by 1-3 C1-6 alkyl groups, or phenyl; and Each p is 0-1, where The ethylene polymer component (A) is prepared in the first polymerization zone and the ethylene polymer component (B) is prepared in the second polymerization zone.

23. The multimodal ethylene copolymer (P) according to claim 1, wherein The multimodal ethylene copolymer (P) is prepared using an organometallic compound (C) of formula (I): (I): (L)mRnMXq(I) in "M" is zirconium (Zr) and hafnium (Hf); Each "X" is Cl; each "L" is a cyclopentadienyl, indenyl or fluorenyl ligand, "R" is a bridging group connecting the L organic ligand, "m" is 2, "n" is 0 or 1, "q" is 2.

24. A film comprising the multimodal ethylene copolymer (P) according to any one of claims 1 to 23, wherein The film is a monolayer film comprising the multimodal ethylene copolymer (P) or a multilayer film wherein at least one layer comprises the multimodal ethylene copolymer (P).

25. The film according to claim 24, wherein The film is a blown extruded film or is part of an extrusion coated substrate comprising a substrate and at least one layer of a multimodal ethylene copolymer (P) extrusion coated on the substrate.

26. Use of the film according to claim 24 or 25 as packaging material.

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