Catalyst support and use thereof in olefin polymerization

Abstract

The present invention relates to a zinc-containing catalyst support, preferably in particulate form, for an olefin polymerisation catalyst, wherein the support comprises particles comprising zinc oxide (ZnO) and / or a derivative thereof and an activator, which preferably is an organoaluminum compound. The present invention further relates to a method for producing particles comprising (ZnO) and / or a derivative thereof and to the use of such particles for preparing a catalyst support. The present invention further relates to catalyst support and catalyst compositions for use in olefin polymerization process, and to olefin polymerization processes using such supports and compositions.

Description

[0001] CATALYST SUPPORT AND USE THEREOF IN OLEFIN POLYMERIZATION

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to the field of olefin polymerisation catalysts and uses thereof in olefin polymerisation reactions. The present invention is directed to a zinc-containing catalyst support, production methods thereof and uses thereof. The present invention further relates to a catalyst composition comprising said support and uses thereof in olefin polymerization processes.

[0004] BACKGROUND OF THE INVENTION

[0005] Olefin polymers, such as polyethylene (PE) and polypropylene (PP), are crucial materials in various industrial applications, including packaging, construction, and automotive industries. The synthesis of these polymers typically involves the use of catalysts to facilitate and optimise the polymerization process. Consequently, efficient catalysis plays a pivotal role in steering the properties and performance of the resulting polymers.

[0006] Polyethylene (PE) and polypropylene (PP) can be made by polymerization of their respective monomers in the presence of a catalyst. Different catalysts can be applied to produce PE and PP. However, homogeneous, i.e. non-supported, catalysts may exhibit poor catalyst lifetimes and cause reactor fouling. To circumvent these issues, catalysts are often heterogenized, which is done by supporting the active species on a support material. Supported olefin polymerization catalysts typically comprise a transition metal, e.g. zirconium, complex impregnated into a solid catalyst support.

[0007] In the case of a smooth and controlled catalyst fragmentation process, the morphology of the catalyst particle can be replicated in the final polymer particle, this is known as the replication phenomenon. Certain olefin polymerization supports such as silica-based catalyst supports may have a high mechanical strength and can be characterized by a low friability. In certain circumstances, such material may be too strong, and its use may result in sub-optimal olefin polymerisation behaviour. In addition, silica supports generally consist of large particles, which are more prone to overheating because of high activity and uneven or non-homogenous active site distribution. The use of such type of catalyst supports can have the disadvantage that the polymerization reaction’s thermal energy does not to disperse enough throughout the whole structure of the formed polymers. This may cause hotspots in the polymers and can lead to the undesired formation of fines in the reactor.

[0008] It is therefore an object of the present invention to provide a catalyst support and / or catalyst composition, which overcomes at least some of the above-mentioned drawbacks of prior art supports and / or compositions. It is therefore also an object of the present invention to provide a catalyst support and / or catalyst composition allowing to produce polymer products with desired properties in a more efficient way.

[0009] It is also an object of the present invention to provide an improved olefin polymerization process, using the catalyst support and / or catalyst composition.

[0010] SUMMARY OF THE INVENTION

[0011] It has now surprisingly been found that some or all of the above objectives can be attained either individually or in any combination by using a zinc-containing catalyst support as defined herein.

[0012] To that end, the present invention relates to a zinc-containing catalyst support for an olefin polymerisation catalyst, preferably for a metallocene-based olefin polymerisation catalyst, wherein the support comprises particles comprising zinc oxide (ZnO) and / or a derivative thereof; and an activator, preferably wherein the activator is an organoaluminum compound.

[0013] The present invention in particular provides a zinc-containing catalyst support for an olefin polymerisation catalyst, preferably for a metallocene-based olefin polymerisation catalyst, wherein the support comprises particles comprising at least 80.0 wt% of zinc oxide (ZnO) with wt% based on the total weight of the particles; and wherein the particles have an average particle size of between at least 2.0 pm and at most 100.0 pm, preferably determined as explained in the example section, and an activator, preferably wherein the activator is an organoaluminum compound,

[0014] In certain preferred embodiments, the zinc-containing catalyst support is in the form of particles, and preferably wherein said particles have a granular, spherical or flower-like morphology.

[0015] Preferably, said ZnO derivative is selected from the group comprising or consisting of zinc hydroxide, hydrates of zinc oxide, solvates of zinc hydroxide, zinc hydroxide carbonate, zinc hydroxide acetate, zinc hydroxide nitrate, zinc hydroxide sulphate, and any combinations thereof.

[0016] In certain preferred embodiments, the particles comprising ZnO and / or a derivative thereof comprise at least 90.0 wt% of ZnO, with wt% based on the total weight of the particles.

[0017] The zinc-containing catalyst support is characterized by several features. For instance, in certain preferred embodiments, the catalyst support has an average particle size of between at least 2.0 and at most 100.0 pm. In certain preferred embodiments, the catalyst support has a BET surface area of between at least 20.00 and at most 750.00 m2 / g. In certain preferred embodiments, the catalyst support has a concentration of Lewis acid sites (LAS) of at least 15.0 pmol / g to at most 100.0 pmol / g.

[0018] In certain preferred embodiments, the amount of activator is comprised between 20.0 wt% and 75.0 wt%, with wt% based on the total weight of the catalyst support. In certain preferred embodiments, the amount of activator is comprised between 25.0 wt% and 45.0 wt%, with wt% based on the total weight of the catalyst support. In certain embodiments is it preferred that the activator is an organoaluminum compound, and that this organoaluminum compound is an aluminoxane. In certain preferred embodiments, the organoaluminum compound is an aluminoxane compound of formula (A1) or (A2)

[0019] Ra-(AI(Ra)-O)x-AIRa2 (A1) for oligomeric, linear aluminoxanes; or

[0020] (-AI(Ra)-O-)y(A2) for oligomeric, cyclic aluminoxanes; wherein x is an integer between 1 and 40, and preferably between 10 and 20; wherein y is an integer between 3 and 40, and preferably between 3 and 20; and wherein each Rais independently selected from a Ci-salkyl, and preferably is a Ci-4alkyl, more preferably is methyl or ethyl.

[0021] In certain preferred embodiments, the catalyst support comprises at least 50.0 wt% of particles comprising ZnO, as defined herein, such as at least 60.0 wt%, or at least 70.0 wt% of said particles, with wt% based on the total weight of the catalyst support.

[0022] The present invention further encompasses a method for the preparation of a zinc-containing catalyst support, preferably a zinc-containing catalyst support as disclosed herein, comprising the steps of: a) forming a zinc-containing precipitate by preparing a solution comprising a zinc salt, a precipitating agent, and optionally a nucleating agent; b) processing said solution into particles comprising zinc oxide (ZnO) and / or a derivative thereof; and c) treating said particles comprising ZnO and / or a derivative thereof with an activator, preferably wherein the activator is an organoaluminum compound, thereby obtaining a zinc- containing catalyst support.

[0023] In certain embodiments of the present method, the zinc salt comprises a water-soluble zinc salt, and preferably is selected from the group consisting of zinc nitrate, zinc chloride, zinc acetate, zinc bromide, zinc iodide, zinc carbonate, zinc sulphate, zinc 2-ethylhexanoate, zinc gluconate, zinc citrate, any hydrates thereof, and any mixtures thereof.

[0024] In certain embodiments of the present method, the precipitating agent comprises a water- soluble basic salt, and preferably is selected from the group consisting of hexamethylenetetramine, NaOH, urea, KOH, NH4OH, NaHCCh, (NH^COa, and any mixtures thereof.

[0025] In certain embodiments of the present method, the nucleating agent comprises a tricarboxylic acid compound, preferably selected from the group consisting of citric acid, citrate salt, isocitric acid, isocitrate salt, aconitic acid, aconitate salt, tricarballylic acid, tricarballylate salt, trimesic acid, trimesate salt, trimellitic acid, trimellitate salt, and mixtures thereof.

[0026] In certain embodiments of the present method, the nucleating agent additionally or alternatively, comprises a surfactant, preferably a cationic surfactant, more preferably an alkylammonium salt of the Formula (NR2xH4-x)Y, wherein R2is a Ci-2oalkyl, x is an integer ranging from 1-4, and Y is a fluoride, chloride, bromide, or iodide.

[0027] In certain embodiments of the present method, step b) comprises subjecting the solution of step a) to spray drying, drying, flash drying, or any combinations thereof, and more preferably spray drying.

[0028] The catalyst support of the invention is particularly advantageous as it is characterized by a high surface activity and allows to prepare olefin polymers having desired properties in an efficient way. Advantageously, the zinc-containing catalyst support is easy to prepare, and may be further fine-tuned and tailored according to certain needs.

[0029] The present invention further encompasses a catalyst composition for olefin polymerization comprising: a zinc-containing catalyst support of the invention, or obtained or obtainable by carrying out a method of the invention for the preparation of a zinc-containing catalyst support; a catalyst component, preferably as defined herein, and more preferably a metallocene catalyst, and optionally a co-catalyst, preferably selected from the group consisting of an organoaluminium compound, an organoboron or organoborate compound, an ionizing ionic compound, or any combinations thereof.

[0030] The present invention further encompasses a method for the preparation of a catalyst composition, preferably a catalyst composition as defined herein, comprising the step of forming a suspension comprising (a) zinc-containing catalyst support, preferably as defined herein, (b) a catalyst component, preferably as defined herein, and (c) optionally a co-catalyst, preferably as defined herein.

[0031] The present invention further relates to the use of particles comprising zinc oxide (ZnO) and / or a derivative thereof, preferably particles comprising zinc oxide (ZnO) and / or a derivative thereof, each as defined herein, for preparing a catalyst support, preferably for preparing a support for an olefin polymerization catalyst, more preferably for preparing a support for a metallocene-based olefin polymerization catalyst.

[0032] The present invention also relates to the use of a zinc-containing catalyst support, as defined herein, or obtained or obtainable by carrying out a method as defined herein, for preparing an olefin polymerization catalyst, preferably for preparing a metallocene-based olefin polymerization catalyst, and / or in a polymerization process for preparing an olefin polymer.

[0033] The present invention further encompasses an olefin polymerization process for preparing an olefin polymer comprising the step of polymerizing an olefin monomer, optionally hydrogen, optionally a diluent, and optionally one or more olefin comonomers, in the presence of at least one catalyst composition as defined herein, or obtained or obtainable by carrying out a method as defined herein. In yet another aspect, the invention also provides for the use of aforementioned catalyst composition, in such olefin polymerization process for preparing an olefin polymer. The present inventions further relate to a polymer, obtained by carrying out polymerization process according to the invention, and to articles made therefrom.

[0034] The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, which illustrate, by way of example, the principles of the invention. The independent and dependent claims set out particular and preferred features of the invention. Features from the dependent claims may be combined with features of the independent or other dependent claims as appropriate.

[0035] The present invention will now be further described. In the following passages, different aspects or embodiments of the invention are defined in more detail. Each aspect or embodiment so defined may be combined with any other unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0036] DETAILED DESCRIPTION OF THE FIGURES

[0037] The teaching of the application is illustrated by the following Figures which are to be considered as illustrative only and do not in any way limit the scope of the claims. Figure 1 is a Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM) image representing an example of a ZnO particle as obtained in experiment 1 of Example 1.

[0038] Figure 2 is a graph showing the average pore volume as a function of average pore diameter following N2-physisorption analysis of particles obtained in experiment 1 of Example 1.

[0039] Figure 3 is a FIB-SEM image representing an example of a particle obtained in experiment 2 of Example 1.

[0040] Figure 4 is a graph showing the average pore volume as a function of average pore diameter following N2-physisorption analysis of the particles obtained in experiment 2 of Example 1.

[0041] Figure 5 is a FIB-SEM image representing an example of a particle obtained in experiment 3 of Example 1.

[0042] Figure 6 is a graph showing the average pore volume as a function of average pore diameter following N2-physisorption analysis of particles as obtained in experiment 3 of Example 1.

[0043] Figure 7 is an X-ray Diffraction (XRD) pattern of particles obtained in experiment 2 of Example 1.

[0044] Figure 8 is a FIB-SEM image representing an embodiment of a catalyst support as prepared in experiment 1 of Example 3.

[0045] Figure 9 is a FIB-SEM image representing an embodiment of a catalyst support as prepared in experiment 2 of Example 3.

[0046] Figure 10 is a FIB-SEM image representing an embodiment of a catalyst support as prepared in experiment 3 of Example 3.

[0047] Figure 11 is a graph showing the average pore volume and average pore diameter following N2-physisorption analysis of the particles as obtained in experiments 1 to 3 of Example 3.

[0048] Figure 12 is a FIB-SEM cross-section image showing an embodiment of a catalyst composition as obtained in Example 4.

[0049] DETAILED DESCRIPTION OF THE INVENTION

[0050] When describing the invention, the terms used are to be construed in accordance with the following definitions, unless a context dictates otherwise.

[0051] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while certain embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art.

[0052] The terms "comprising", "comprises" and "comprised of" as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements, or method steps. It will be appreciated that the terms "comprising", "comprises" and "comprised of" as used herein comprise the terms "consisting of", "consists" and "consists of".

[0053] As used in the specification and the appended claims, the singular forms "a", "an," and "the" include plural referents unless the context clearly dictates otherwise. By way of example, "a step" means one step or more than one step.

[0054] As used herein, the term “and / or” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a list is described as comprising group A, B, and / or C, the list can comprise A alone, B alone, C alone, A and B in combination, A and C in combination, B and C in combination, or A, B, and C in combination.

[0055] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art.

[0056] The recitation of numerical ranges by endpoints includes all intervening values between the lower and upper endpoints, as well as the recited endpoints. Intervening values may be integers or, where applicable, fractions, i.e., more broadly any real numbers such as any rational numbers. For instance: 1 to 5 can include 1 , 2, 3, 4 when referring to, for example, a number of elements, and can also include 1 .5, 2, 2.75 and 3.80, when referring to, for example, measurements. The recitation of endpoints also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). This applies to numerical ranges irrespective of whether they are introduced by the expression “from... to...” or the expression “between... and...” or another expression. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, each sub-range between any stated value in a stated range and any other stated value in that stated range is also specifically disclosed. Each sub-range between any stated value in a stated range and either the lower endpoint or the upper endpoint of the stated range is also specifically disclosed. The stated value may be an isolated value, or an endpoint of a range subsumed by or overlapping with the stated range. For example, for a stated range with lower endpoint L1 and upper endpoint U1 (i.e., stated range L1-LI1) and a stated sub-range nested within the stated range with lower endpoint L2 and upper endpoint U2 (i.e., stated sub-range L2-LI2), also specifically disclosed are the subranges L1-L2, L1-U2, L2-U1 , and U2-U1.

[0057] As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result.

[0058] As used herein, the term “about” is used to provide flexibility to a numerical value or range endpoint by providing that a given value may be “a little above” or “a little below” said value or endpoint, depending on the specific context. Unless otherwise stated, use of the term “about” in accordance with a specific number or numerical range should also be understood to provide support for such numerical terms or range without the term “about”. For example, the recitation of “about 30” should be construed as not only providing support for values a little above and a little below 30, but also for the actual numerical value of 30 as well.

[0059] The terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, unless specified. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the disclosure described herein are capable of operation in other sequences than described or illustrated herein.

[0060] Reference in this specification may be made to methods that provide “improved” performance (e.g. increased or decreased results, depending on the context). It is to be understood that unless otherwise stated, such “improvement” is a measure of a benefit obtained based on a comparison to methods in the prior art. Furthermore, it is to be understood that the degree of improved performance may vary between disclosed embodiments and that no equality or consistency in the amount, degree, or realization of improved performance is to be assumed as universally applicable.

[0061] The terms “wt%,” “vol%”, or “mol%” refers to a weight percentage of a component, a volume percentage of a component, or molar percentage of a component, respectively, based on the total weight, the total volume of material, or total moles, which includes the component.

[0062] Whenever the term “substituted” is used herein, it is meant to indicate that one or more hydrogen atoms on the atom indicated in the expression using “substituted” is replaced with a selection from the indicated group, provided that the indicated atom’s normal valence is not exceeded, and that the substitution results in a chemically stable compound, i.e. a compound that is sufficiently robust to survive isolation from a reaction mixture.

[0063] The term “halo” or “halogen” as a group or part of a group is generic for fluoro, chloro, bromo, iodo.

[0064] The term "alkyl" as a group or part of a group, refers to a hydrocarbyl group of formula CnH2n+i wherein n is a number greater than or equal to 1. Alkyl groups may be linear or branched and may be substituted as indicated herein. Generally, alkyl groups of this invention comprise from 1 to 20 carbon atoms, preferably from 1 to 10 carbon atoms, preferably from 1 to 6 carbon atoms, more preferably from 1 to 4 carbon atoms. When a subscript is used herein following a carbon atom, the subscript refers to the number of carbon atoms that the named group may contain. For example, the term "Ci-2oalkyl", as a group or part of a group, refers to a hydrocarbyl group of formula -CnH2n+i wherein n is a number ranging from 1 to 20. Thus, for example, “Ci-salkyl” includes all linear or branched alkyl groups with between 1 and 8 carbon atoms, and thus includes methyl, ethyl, n-propyl, i-propyl, butyl, and its isomers (e.g. n-butyl, i-butyl, and t-butyl); pentyl and its isomers, hexyl, and its isomers, etc. A “substituted alkyl" refers to an alkyl group substituted with one or more substituent(s) (for example 1 to 3 substituent(s), for example 1 , 2, or 3 substituent(s)) at any available point of attachment.

[0065] The term “alkoxy" or “alkyloxy”, as a group or part of a group, refers to a group having the formula -ORbwherein Rbis alkyl as defined herein above. Non-limiting examples of suitable alkoxy include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tertbutoxy, pentyloxy and hexyloxy.

[0066] When describing the present invention, the terms used are to be construed in accordance with the following definitions, unless a context dictates otherwise. Preferred statements (features) and embodiments and uses of this invention are set herein below. Each statement and embodiment of the invention so defined may be combined with any other statement and / or embodiment unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features or statements indicated as being preferred or advantageous. Hereto, the present invention is in particular captured by any one or any combination of one or more of the below numbered statements and embodiments, with any other aspect and / or embodiment.

[0067] 1 . A zinc-containing catalyst support for an olefin polymerisation catalyst, preferably for a metallocene-based olefin polymerisation catalyst, wherein the support comprises particles comprising zinc oxide (ZnO) and / or a derivative thereof; and an activator, preferably wherein the activator is an organoaluminum compound, wherein the particles comprising zinc oxide (ZnO) comprise at least 80.0 wt% of ZnO, with wt% based on the total weight of the particles, and have an average particle size of between at least 2.0 and at most 100.0 pm.

[0068] 2. The catalyst support according to statement 1 , wherein said zinc-containing catalyst support is in the form of particles, and preferably wherein said particles have a granular, spherical or flower-like morphology.

[0069] 3. The catalyst support according to the preceding statements 1 or 2, wherein the particles comprising ZnO and / or a derivative thereof are at least partially impregnated with said activator.

[0070] 4. The catalyst support according to any one of the preceding statements, wherein the ZnO derivative is selected from the group comprising or consisting of zinc hydroxide, hydrates of zinc oxide, solvates of zinc hydroxide, zinc hydroxide carbonate, zinc hydroxide acetate, zinc hydroxide nitrate, zinc hydroxide sulphate, and any combinations thereof.

[0071] 5. The catalyst support according to any one of the preceding statements, wherein the catalyst support has an average particle size of between at least 2.0 and at most 90.0 pm, or between at least 2.0 and at most 80.0 pm, or between at least 4.0 and at most 80.0 pm, or between at least 4.0 and at most 70.0 pm, or between at least 4.0 and at most 50.0 pm.

[0072] 6. The catalyst support according to any one of the preceding statements, wherein the catalyst support has a BET surface area of between at least 20.00 and at most 750.00 m2 / g, or between at least 20.00 and at most 600.00 m2 / g, or between at least 20.00 and at most 450.00 m2 / g, or between at least 20.00 and at most 300.00 m2 / g, or between at least 20.00 and at most 275.00 m2 / g, or between at least 20.00 and at most 250.00 m2 / g, or between at least 20.00 and at most 200.00 m2 / g, or between at least 20.00 and at most 150.00 m2 / g, or between at least 20.00 and at most 100.00 m2 / g, or between at least 25.00 and at most 85.00 m2 / g, or between at least 30.00 and at most 82.50 m2 / g, or between at least 40.00 and at most 80.00 m2 / g. The catalyst support according to any one of the preceding statements, wherein the catalyst support has an average pore volume of between at least 0.100 and at most 2.000 cm3 / g, or between at least 0.100 and at most 1.750 cm3 / g, or between at least 0.100 and at most 1.500 cm3 / g, or between at least 0.100 and at most 1.400 cm3 / g, or between at least 0.100 and at most 1.300 cm3 / g, or between at least 0.100 and at most 1.200 cm3 / g, or between at least 0.100 and at most 1.100 cm3 / g, or between at least 0.100 and at most 1.000 cm3 / g, or between at least 0.100 and at most 0.750 cm3 / g, or between at least 0.100 and at most 0.500 cm3 / g, or between at least 0.100 and at most 0.250 cm3 / g. The catalyst support according to any one of the preceding statements, wherein the catalyst support has an average pore size of between at least 1 and at most 150 nm, or between at least 1 and at most 125 nm, or between at least 1 and at most 100 nm, or between at least 1 and at most 75 nm, or between at least 2 and at most 75 nm, or between at least 3 and at most 75 nm, or between at least 4 and at most 75 nm, or between at least 5 and at most 75 nm, or between at least 5 and at most 50 nm. The catalyst support according to any one of the preceding statements, wherein the catalyst support has a Young’s modulus (E) of between at least 90.0 and at most 170.0 GPa, or between at least 90.0 and at most 160.0 GPa, or between at least 100.0 and at most 160.0 GPa, or between at least 110.0 and at most 160.0 GPa, or between at least 120.0 and at most 160.0 GPa. The catalyst support according to any one of the preceding statements, wherein the catalyst support has a concentration of Lewis acid sites (LAS) of between at least 15.0 pmol / g and at most 100.0 pmol / g, or between at least 15.0 pmol / g and at most 90.0 pmol / g, or between at least 15.0 pmol / g and at most 80.0 pmol / g, or between at least 15.0 pmol / g and at most 70.0 pmol / g, or between at least 15.0 pmol / g and at most 50.0 pmol / g, or between at least 20.0 pmol / g and at most 50.0 pmol / g, or between at least 30.0 pmol / g and at most 50.0 pmol / g. The catalyst support according to any one of the preceding statements, wherein the particles comprising ZnO and / or a derivative thereof_comprise at least 82.5 wt% of ZnO, or at least 85.0 wt% of ZnO, or at least 87.5 wt% of ZnO, or at least 90.0 wt% of ZnO, or at least 92.5 wt% of ZnO, or at least 95.0 wt% of ZnO, with wt% based on the total weight of the particles. The catalyst support according to any one of the preceding statements, wherein the particles comprising ZnO and / or a derivative thereof have an O:Zn atomic ratio of at least 1 .0 to at most 2.0, or at least 1.0 to at most 1.8, or at least 1 .3 to at most 1 .8, or at least

[0073] 1 .3 to at most 1 .6. The catalyst support according to any one of the preceding statements, wherein the particles comprising ZnO and / or a derivative thereof have an average particle size of between at least 2.0 and at most 100.0 pm, or between at least 2.0 and at most 90.0 pm, or between at least 2.0 and at most 80.0 pm, or between at least 4.0 and at most 80.0 pm, or between at least 4.0 and at most 70.0 pm, or between at least 4.0 and at most 50.0 pm. The catalyst support according to any one of the preceding statements, wherein the particles comprising ZnO and / or a derivative thereof have a BET surface area of between at least 10.00 and at most 250.00 m2 / g, or between at least 10.00 and at most 200.00 m2 / g, or between at least 15.00 and at most 180.00 m2 / g, or between at least 20.00 and at most 165.00 m2 / g. The catalyst support according to any one of the preceding statements, wherein the particles comprising ZnO and / or a derivative thereof have an average pore volume of between at least 0.100 and at most 1.500 cm3 / g, or between at least 0.100 and at most 1 .300 cm3 / g, or between at least 0.100 and at most 1 .000 cm3 / g, or between at least 0.100 and at most 0.750 cm3 / g, or between at least 0.100 and at most 0.500 cm3 / g, or between at least 0.100 and at most 0.250 cm3 / g. The catalyst support according to any one of the preceding statements, wherein the particles comprising ZnO and / or a derivative thereof have an average pore size of between at least 1 and at most 150 nm, or between at least 1 and at most 125 nm, or between at least 1 and at most 100 nm, or between at least 1 and at most 75 nm, or between at least 2 and at most 75 nm, or between at least 3 and at most 75 nm, or between at least 4 and at most 75 nm, or between at least 5 and at most 75 nm, or between at least 5 and at most 50 nm. The catalyst support according to any one of the preceding statements, wherein o the amount of activator is comprised between 20.0 wt% and 75.0 wt%, or between 20.0 wt% and 65.0 wt%, or between 20.0 wt% and 55.0 wt%, or between 20.0 wt% and 50.0 wt%, or between 25.0 wt% and 45.0 wt%, with wt% based on the total weight of the catalyst support, and / or o wherein the catalyst support comprises at least 50.0 wt% of said particles comprising ZnO, such as at least 60.0 wt% or at least 70.0 wt%, or at least 80.0 wt% of said particles, with wt% based on the total weight of the catalyst support. The catalyst support according to any one of the preceding statements, wherein the organoaluminum compound is an aluminoxane compound, and preferably an aluminoxane compound of formula (A1) or (A2)

[0074] Ra-(AI(Ra)-O)x-AIRa2 (A1) for oligomeric, linear aluminoxanes; or

[0075] (-AI(Ra)-O-)y(A2) for oligomeric, cyclic aluminoxanes; wherein x is an integer between 1 and 40, and preferably between 10 and 20; wherein y is an integer between 3 and 40, and preferably between 3 and 20; and wherein each Rais independently selected from a Ci-salkyl , and preferably is a Ci- 4alkyl, more preferably is methyl or ethyl. The catalyst support according to any one of the preceding statements, wherein the organoaluminum compound is methyl alumoxane (MAO) or ethyl alumoxane. A method for the preparation of particles comprising zinc oxide (ZnO) and / or a derivative thereof, preferably particles comprising zinc oxide as defined in any one of the preceding statements 1 to 19, comprising the steps of: a) forming a zinc-containing precipitate by preparing a solution comprising a zinc salt, a precipitating agent, and optionally a nucleating agent; b) processing said solution into particles comprising ZnO and / or a derivative thereof. A method for the preparation of a zinc-containing catalyst support, preferably a zinc- containing catalyst support according to any one of the preceding statements 1 to 19, comprising the steps of: a) forming a zinc-containing precipitate by preparing a solution comprising a zinc salt, a precipitating agent, and optionally a nucleating agent; b) processing said solution into particles comprising zinc oxide (ZnO) and / or a derivative thereof; and c) treating said particles comprising ZnO and / or a derivative thereof with an activator, preferably wherein the activator is an organoaluminum compound, thereby obtaining a zinc-containing-catalyst support. The method according to the preceding statement 20 or 21 , wherein the solution has a pH of between at least 4 and at most 9, or between at least 5 and at most 9, or between at least 6 and at most 9, or between at least 7 and at most 9. The method according to any one of the preceding statements 20 to 22, wherein the zinc salt comprises a water-soluble zinc salt, and preferably is selected from the group consisting of zinc nitrate, zinc chloride, zinc acetate, zinc bromide, zinc iodide, zinc carbonate, zinc sulphate, zinc 2-ethylhexanoate, zinc gluconate, zinc citrate, any hydrates thereof, and any mixtures thereof.

[0076] 24. The method according to any one of the preceding statements 20 to 23, wherein the precipitating agent comprises a water-soluble basic salt, and preferably is selected from the group consisting of hexamethylenetetramine, NaOH, urea, KOH, NH4OH, NaHCCh, (NH4)2CO3, and any mixtures thereof.

[0077] 25. The method according to any one of the preceding statements 20 to 24, wherein the solution comprises a zinc salt: precipitating agent molar ratio of at least 1 :1.2 to at most 1 :4, preferably a molar ratio of 1 :2.

[0078] 26. The method according to any one of the preceding statements 20 to 25, wherein the nucleating agent comprises

[0079] - a tricarboxylic acid compound, preferably selected from the group consisting of citric acid, citrate salt, isocitric acid, isocitrate salt, aconitic acid, aconitate salt, tricarballylic acid, tricarballylate salt, trimesic acid, trimesate salt, trimellitic acid, trimellitate salt, and mixtures thereof, and / or

[0080] - a surfactant, preferably a cationic surfactant, more preferably an alkylammonium salt of the Formula (NR2xH4-x)Y, wherein R2is a Ci-2oalkyl, x is an integer ranging from 1- 4, and Y is a fluoride, chloride, bromide, or iodide.

[0081] 27. The method according to any one of the preceding statements 20 to 26, wherein the solution comprises a zinc salt: nucleating agent molar ratio of at least 1 :0.05 to at most 1 :0.5, or at least 1 :0.25 to at most 1 :0.5.

[0082] 28. The method according to any one of the preceding statements 20 to 27, wherein step a) further comprises heating the solution to a temperature of between 100 °C and 180 °C, or between 110 °C and 170 °C, or between 120 °C and 160 °C.

[0083] 29. The method according to any one of the preceding statements 20 to 28, wherein step b) comprises the steps of b1) separating the zinc-containing precipitate from said solution; b2) optionally, drying said separated precipitate of step b1), preferably at a temperature of between 40 and 120 °C; and b3) optionally, calcining said separated precipitate of step b1) or b2); preferably wherein calcining is performed at a temperature of at least 200 °C to at most 800 °C, and preferably during 2 to 8 hours.

[0084] 30. The method according to any one of the preceding statements 20 to 29, wherein step b) comprises subjecting the solution of step a) to spray drying, drying, flash drying, or any combinations thereof, and preferably to spray drying. 31. The method according to any one of the preceding statements 20 to 30, wherein spray drying of the solution is carried out in the presence of a heated gas, preferably air, nitrogen, or a noble gas, preferably at a spray pressure of between 0.1 and 1.0 MPa, such as between 0.1 and 0.8 MPa.

[0085] 32. The method according to any one of the preceding statements 20 to 31 , wherein the heated gas has a flow rate of at least 0.001 m3 / min, such as at least 0.01 m3 / min, such as between 0.01 and 1.0 m3 / min, or between 0.01 and 0.9 m3 / min, or between 0.01 and 0.8 m3 / min, or between 0.01 and 0.7 m3 / min, or between 0.01 and 0.6 m3 / min.

[0086] 33. The method according to any one of the preceding statements 20 to 32, wherein the heated gas has a temperature of between at least 100 °C and at most 250 °C, or between at least 120 °C and at most 250 °C, or between at least 120 °C and at most 220 °C, or between at least 150 °C and at most 220 °C, or between at least 150 °C and at most 200 °C.

[0087] 34. The method according to any one of the preceding statements 20 to 33, wherein the solution is contacted with the heated gas in a drying chamber, and wherein the solution is provided to said drying chamber at a flow rate of between 0.1 and 1000.0 L / h, such as between 1.0 and 1000.0 L / h, or between 50.0 and 750.0 L / h, or between 100.0 and 750.0 L / h, or between 250.0 and 750.0 L / h.

[0088] 35. The method according to any one of the preceding statements 20 to 34, wherein the concentration of the precipitate in the solution is between 10.0 and 500.0 g / L, or between 10.0 and 450.0 g / L, or between 10.0 and 400.0 g / L, or between 10.0 and 350.0 g / L, or between 20.0 and 350.0 g / L, or between 30.0 and 350.0 g / L, or between 40.0 and 350.0 g / L, or between 50.0 and 350.0 g / L.

[0089] 36. The method according to any one of the preceding statements 20 to 35, wherein the particles comprising ZnO and / or a derivative thereof obtained in step b) are as defined in any one of the statements 1 to 19.

[0090] 37. The method according to any one of the preceding statements 20 to 36, wherein the particles comprising ZnO and / or a derivative thereof are treated with the activator in step c) by mixing a mixture of the particles and an activator solution for at least 1 hour to at most 24 hours; preferably at a temperature of between 100 °C and 180 °C, or between 120 °C and 180 °C, or between 120 °C and 160 °C; and preferably under an inert atmosphere, more preferably a nitrogen atmosphere.

[0091] 38. The method according to any one of the preceding statements 20 to 37, wherein the amount of activator in the mixture is comprised between at least 10 wt% and at most 60 wt%, or between at least 20.0 wt% and at most 50.0 wt% of activator, with wt% the total weight of the mixture. 39. The method according to any one of the preceding statements 20 to 38, wherein the organoaluminum compound is as defined in any one of the statements 1 to 19.

[0092] 40. A zinc-containing catalyst support obtained or obtainable by carrying out the method according to any one of statements 21 to 39.

[0093] 41. A catalyst composition comprising: a zinc-containing catalyst support according to any one of statements 1 to 19, or obtained or obtainable by carrying out a method according to any one of statements 21 to 39; and a catalyst component, and optionally a co-catalyst, preferably selected from the group consisting of an organoaluminium compound, an organoboron or organoborate compound, an ionizing ionic compound, or any combinations thereof.

[0094] 42. The catalyst composition according to the preceding statement 41 , wherein the catalyst component is at least partially immobilized on the catalyst support.

[0095] 43. The catalyst composition according to any one of the preceding statements 41 or 42, comprising between at least 0.001 and at most 5.0 wt%, or between at least 0.005 and at most 5.0 wt%, or between at least 0.01 and at most 5.0 wt%, or between at least 0.01 and at most 4.5 wt%, or between at least 0.01 and at most 4.0 wt%, of the catalyst component, with wt% based on the total weight of the catalyst composition.

[0096] 44. The catalyst composition according to any one of the preceding statements 41 to 43, wherein the catalyst component is selected from the group consisting of a Ziegler-Natta catalyst, a Phillips catalyst, a metallocene catalyst, a phosphinimine catalyst, a constrained geometry catalyst, and combinations thereof, and preferably wherein the catalyst component is a metallocene catalyst.

[0097] 45. The catalyst composition according to any one of the preceding statements 41 to 44, wherein the catalyst composition has a BET surface area of between at least 20.0 and at most 800.0 m2 / g, or between at least 20.0 and at most 750.0 m2 / g, or between at least 20.0 and at most 700.0 m2 / g, or between at least 20.0 and at most 650.0 m2 / g, or between at least 20.0 and at most 600.0 m2 / g, or between at least 20.0 and at most 550.0 m2 / g, or between at least 20.0 and at most 500.0 m2 / g, or between at least 30.0 and at most 450.0 m2 / g, between 30 and 200 m2 / g.

[0098] 46. The catalyst composition according to any one of the preceding statements 41 to 45, wherein the catalyst composition has an average pore volume of between at least 0.100 and at most 2.000 cm3 / g, or between at least 0.100 and at most 1 .500 cm3 / g, or between at least 0.100 and at most 1.000 cm3 / g. 47. The catalyst composition according to any one of the preceding statements 41 to 46, wherein the catalyst composition has an average pore size of between at least 1 nm and at most 50 nm, or between at least 1 nm and at most 45 nm, or between at least 1 nm and at most 40 nm, or between at least 1 nm and at most 35 nm, or between at least 1 nm and at most 30 nm, or between at least 1 nm and at most 25 nm, or between at least 1 nm and at most 20 nm, or between at least 1 nm and at most 15 nm.

[0099] 48. The catalyst composition according to any one of the preceding statements 41 to 47, wherein the weight ratio of catalyst supportcatalyst component is at least 1 :70, or at least 1 :80, or at least 1 :90, or at least 1 :100, or at least 1 :110, or at least 1 :120, or at least 1 :130, or at least 1 : 140, or at least 1 : 150.

[0100] 49. The catalyst composition according to any one of the preceding statements 41 to 48, wherein the co-catalyst is an organoaluminium represented by the formula AIR1X, wherein each R1is the same or different and is selected from the group consisting of halogens, alkoxy, and alkyl, preferably halogens, Ci-i2alkyl, and Ci-i2alkoxy, and x is an integer from 1 to 3.

[0101] 50. The catalyst composition according to any one of the preceding statements 41 to 49, wherein the co-catalyst is an organoaluminium selected from the group consisting of trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminum chloride, and mixtures thereof, and preferably is triethylaluminum (TEA).

[0102] 51 . A method for the preparation of a catalyst composition, preferably a catalyst composition according to any one of statements 41 to 50, comprising forming a suspension comprising: a) a zinc-containing catalyst support, preferably according to any one of statements 1 to 19; b) a catalyst component, preferably as defined in statement 44; and c) optionally a co-catalyst, preferably as defined in any one of statements 49 to 50.

[0103] 52. The method according to the preceding statement 51 , wherein the weight ratio of catalyst supportcatalyst component is at least 1 :70, or at least 1 :80, or at least 1 :90, or at least 1 : 100, or at least 1 :110, or at least 1 :120, or at least 1 : 130, or at least 1 : 140, or at least 1 :150.

[0104] 53. A catalyst composition obtained or obtainable by carrying out the method according to any one of statements 51 or 52.

[0105] 54. Use of particles comprising zinc oxide (ZnO) and / or a derivative thereof, preferably as defined in any one of statements 1 to 19, or obtained or obtainable by carrying out a method according to any one of statements 20 and 22 to 36, preferably for preparing a support for a olefin polymerization catalyst, more preferably for preparing a support for a metallocene-based olefin polymerization catalyst. Use of particles comprising zinc oxide (ZnO) and / or a derivative thereof, preferably as defined in any one of statements 1 to 19, or obtained or obtainable by carrying out a method according to any one of statements 20 and 22 to 36, in an olefin polymerization process for preparing an olefin polymer, and preferably in metallocene-catalysed olefin polymerization process. Use of a zinc-containing catalyst support according to any one of statements 1 to 19, or obtained or obtainable by carrying out a method according to any one of statements 21 to 39, for preparing an olefin polymerization catalyst composition, preferably for preparing a metallocene-based olefin polymerization catalyst. Use of a zinc-containing catalyst support according to any one of statements 1 to 19, or obtained or obtainable by carrying out a method according to any one of statements 21 to 39, in a polymerization process for preparing an olefin polymer. Use of a catalyst composition according to any one of statements 41 to 50, or obtained or obtainable by carrying out a method according to any one of statements 51 or 52 in a polymerization process for preparing an olefin polymer. The use according to any one of the preceding statements 55, 57 or 58, wherein the polymerization process is performed in slurry phase. The use according to any one of the preceding statements 55, and 57 to 59, wherein the olefin polymer is polyethylene, such as a polyethylene homopolymer, or a copolymer of ethylene with one or more C3-10 olefin comonomers. The use according to any one of the preceding statements 55, and 57 to 59, wherein the olefin polymer is polypropylene, such as isotactic polypropylene, or a heterophasic propylene copolymer (impact polypropylene). An olefin polymerization process for preparing an olefin polymer comprising the step of polymerizing an olefin monomer, optionally hydrogen, optionally a diluent, and optionally one or more -olefin comonomers, in the presence of at least one catalyst composition according to any one of statements 41 to 50, or that is obtained or obtainable by carrying out a method according to any one of statements 51 or 52. The process according to the preceding statement 62, wherein the process is performed in slurry phase. An olefin polymer obtainable or obtained by carrying out a process according to any of the statements 62 to 63. 65. The olefin polymer according to the preceding statement 64, comprising the catalyst composition according to any one of statements 41 to 50 and / or fragments of said catalyst composition.

[0106] 66. The olefin polymer according to any one of the preceding statements 64 or 65, wherein the amount of catalyst composition and / or fragments of the catalyst composition in said polymer is lower than 2000 ppm, preferably lower than 1500 ppm, preferably lower than 1000 ppm.

[0107] 67. An article comprising or made from an olefin polymer according to any one of statements 64 to 66.

[0108] The present invention is based on the surprising finding that a zinc-containing catalyst support and components thereof are particularly suitable for preparing a polymerization catalyst. Compared to silica-based catalyst supports, used in olefin polymerization reactions, the present zinc-containing catalyst support may provide several advantages in terms of catalyst and / or polymerization activity and productivity. In particular, it has been found that the zinc- containing catalyst support according to the present invention may provide improved catalyst activation, which results in more homogeneous polymerization conditions and dispersion of thermal energy.

[0109] Accordingly, an aspect of the present invention relates to a zinc-containing catalyst support, preferably for supporting an olefin polymerisation catalyst, more preferably for supporting a metallocene-based olefin polymerisation catalyst.

[0110] In accordance with the present invention, a zinc-containing catalyst support is provided that comprises particles comprising zinc oxide (ZnO) and / or a derivative thereof and an activator.

[0111] In some embodiments of the present invention, a zinc-containing catalyst support for an olefin polymerisation catalyst, preferably for a metallocene-based olefin polymerisation catalyst, is provided, wherein the support comprises particles comprising zinc oxide (ZnO) and / or a derivative thereof; and an organoaluminum compound as activator

[0112] Hereunder, particularities and properties of the zinc-containing catalyst support of the invention and components thereof will be discussed in greater detail.

[0113] The present invention provides a zinc-containing catalyst support.

[0114] The term “catalyst support”, as used herein, refers to a solid material or a solid structure, which is configured to support a catalyst. In this context, the terms “supporting”, “mounting”, “applying”, “impregnating” are used herein as synonyms and intend to refer to the application of a catalyst on such solid support. As used herein, the terms “catalyst” and "catalyst component” are used herein as synonyms and refer to a substance that causes a change in the rate of a reaction. The support of the present invention may be particularly suitable for supporting catalysts that catalyze a polymerization reaction of olefins to olefin polymers, i.e. olefin polymerization catalysts.

[0115] Advantageously, the present catalyst support provides structural and functional improvements to various polymerization processes wherein various types of catalysts can be used. Nonlimiting examples of suitable catalyst or catalyst components that may be supported by the zinc-containing catalyst support according to the invention include metallocene catalysts, Ziegler-Natta catalysts, Phillips catalysts, phosphinimine catalysts, and preferably include metallocene catalysts, in view of their high catalytic performance and stereoselectivity, allowing to tailor the polymer microstructure and properties.

[0116] The present supported catalyst is used in heterogeneous catalysis. Unlike homogeneous catalysis, where the reactants, products and catalyst exist in the same phase, heterogeneous catalysis involves catalysis where the phase of catalysts differs from that of the reactants or products. Advantageously, heterogeneous catalysts may facilitate reactions by providing active sites on their surfaces where reactant molecules can adsorb, react, and subsequently desorb as products.

[0117] In accordance with the present invention, the catalyst support of the invention comprises particles comprising zinc oxide (ZnO) and / or a derivative thereof. It has been found that particles comprising or consisting of zinc oxide and / or a derivative thereof as defined herein provide several advantages over conventional inorganic oxides, such as silica, alumina, or silica-coated alumina, commonly used as a catalyst support during olefin polymerization.

[0118] The terms “particles comprising ZnO” and “ZnO particles” are used interchangeably. According to the present invention, the ZnO particles as disclosed herein may additionally or alternatively comprise ZnO derivatives. For instance, such derivatives may be obtained during the production of ZnO particles. Non-limiting examples of ZnO derivatives are zinc hydroxide (Zn(OH)2), hydrates of zinc oxide (e.g., ZnO x W, wherein x is a positive number), solvates of zinc hydroxide (e.g., ZnO yCHsOH, wherein y is a positive number), zinc hydroxide carbonate (e.g., Zns(OH)6(CO3)2), zinc hydroxide acetate (e.g., Zns(OH)8(CH3CO2)2), zinc hydroxide nitrate (e.g., Zns(OH)8(NO3)2), zinc hydroxide sulphate (e.g., Zn4(OH)eSO4), and any combinations thereof. The present invention further encompasses any stoichiometric compositions or hydrates of the listed ZnO derivatives (e.g., Zns(OH)8(CH3CO2)2-2H2O or Zn5(OH)8(NO3)2-2H2O). The term “hydrates of zinc oxide” refers to compounds wherein zinc oxide (ZnO) is associated with one or more water molecules. Such water molecules may be either physically trapped within the ZnO crystal lattice or chemically bonded to zinc ions.

[0119] The term “solvates of zinc oxide” refers to compounds wherein zinc oxide (ZnO) is associated with one or more solvent molecules other than water. For instance, suitable solvents include alcohols, such as methanol and ethanol, and ketones such as acetone. Other polar solvents may also form suitable zinc oxide solvates as is apparent to the person skilled in the art. Such solvent molecules may be either physically trapped within the ZnO crystal lattice or chemically bonded to zinc ions.

[0120] It has been found that, contrary to aforementioned prior art catalyst supports comprising silica particles, the present support comprising ZnO particles and / or a derivative thereof may provide a more controlled activity and a more even, i.e. homogeneous, active site distribution. It was found that a relatively lower particle size and surface area of such particles can stabilize active catalyst species, resulting in a more controlled catalyst activity throughout the polymerization reaction. In addition, said particles may advantageously be less prone to uncontrolled detachment or desorption of active catalyst species, which can result in an improved polymerization process.

[0121] In preferred embodiments, the particles comprising ZnO and / or a derivative thereof have a granular, spherical, or flower-like morphology. The term “granular”, as used herein, refers to a particle morphology comprising multiple granules or clusters that are interconnected to form a three-dimensional network. The term “spherical”, as used herein, refers to a particle morphology comprising spheres with an essentially smooth and uniform surface. The term “flower- 1 ike”, as used herein, refers to a particle morphology comprising a platelet structure at the surface of the particles that resembles the shape of a flower. Said platelet structure may comprise nanosheets or nanorods of zinc oxide. In view of the foregoing, it will be clear that the particles comprising ZnO and / or a derivative thereof as disclosed herein have a substantially circular or round shape. Therefore, the terms “average particle size” and “average particle diameter” are used herein interchangeably.

[0122] The morphology of the particles comprising ZnO and / or a derivative thereof as a whole, or of components or parts thereof, may be determined by any technique known to the person skilled in the art. For instance, morphology measurements can be performed using microscopy. In particular, Scanning Electron Microscopy (SEM) images of the particles allow to assess the shape and relative size of the particles. In some other embodiments, the particles comprising ZnO and / or a derivative thereof have a hexagonal wurtzite crystal structure. Advantageously, the hexagonal wurtzite crystal structure provides the particles comprising ZnO and / or a derivative thereof with good stability and sufficient mechanical integrity. The hexagonal wurtzite structure may be determined by Powder X-Ray Diffraction (PXRD) analysis as would be apparent to a person skilled in the art. In particular, X-rays are typically directed onto the crystalline sample, preferably a fine powder of the particles comprising ZnO and / or a derivative thereof, at various angles. The resulting diffraction pattern is analysed using Bragg's Law, which relates the angle of diffraction (0), the wavelength of X-rays (A), and the interplanar spacing (d) in the crystal lattice. The equation is given by nA = 2d sin(0), where n is the order of diffraction. The diffracted X-rays are detected, and the resulting diffraction pattern is recorded as a series of peaks. The positions and intensities of these peaks provide information about the crystal lattice and spacing. Preferably, the particles comprising ZnO and / or a derivative thereof are characterized by PXRD peaks at 20 of 134.35, 36.25, 47.50 and 56.60° (±0.1°).

[0123] Preferably, the particles comprising ZnO and / or a derivative thereof as applied in the present invention are microparticles. In some embodiments, the particles comprising ZnO and / or a derivative thereof have an average particle size of at least 2.0 pm, or at least 3.0 pm, or at least 4.0 pm, or at least 5.0 pm, or at least 10.0 pm, or at least 15.0 pm, or at least 20.0 pm. In some embodiments, the particles comprising ZnO and / or a derivative thereof have an average particle size of at most 100.0 pm, or at most 90.0 pm, or at most 80.0 pm, or at most 70.0 pm, or at most 50.0 pm. In some preferred embodiments, the particles comprising ZnO and / or a derivative thereof have an average particle size of between at least 2.0 and at most 100.0 pm, or between at least 2.0 and at most 90.0 pm, or between at least 2.0 and at most 80.0 pm, or between at least 4.0 and at most 80.0 pm, or between at least 4.0 and at most 70.0 pm, or between at least 4.0 and at most 50.0 pm, or between at least 10.0 and at most 45.0 pm. Advantageously, such (micro) particles of a controlled size may facilitate efficient mass transport of reactants and products to and from the support during polymerization.

[0124] The average particle size of the particles comprising ZnO and / or a derivative thereof may be determined by Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM) as outlined in the methodology section below. A suitable FIB-SEM system includes a FEI Helios Nanolab G3 instrument operating at 0.8 pA to 22 nA and 200 V to 30 kV.

[0125] In certain embodiments, the particles comprising ZnO and / or a derivative thereof have an average particle size D50 of at least 2.0 pm, or at least 3.0 pm, or at least 4.0 pm, or at least 5.0 pm, or at least 10.0 pm, or at least 15.0 pm, or at least 20.0 pm. The D50 is defined as the particle size for which fifty percent by weight of the particles has a size lower than the D50. In some embodiments, the particles comprising ZnO and / or a derivative thereof have an average particle size D50 of at most 100.0 pm, or at most 90.0 pm, or at most 80.0 pm, or at most 70.0 pm, or at most 50.0 pm.

[0126] In some preferred embodiments, the particles comprising ZnO and / or a derivative thereof have an average particle size D50 of between at least 2.0 and at most 100.0 pm, or between at least 2.0 and at most 90.0 pm, or between at least 2.0 and at most 80.0 pm, or between at least 4.0 and at most 80.0 pm, or between at least 4.0 and at most 70.0 pm, or between at least 4.0 and at most 50.0 pm, or between at least 10.0 and at most 45.0 pm. Measurement of the D50 particle sizes can be made according to the International Standard ISO 13320:2009 by static laser light scattering, as explained in the example section.

[0127] The particles comprising ZnO and / or a derivative thereof are preferably porous particles. In some embodiments, the particles comprising ZnO and / or a derivative thereof have a BET surface area of at least 10.00 m2 / g, or at least 15.00 m2 / g, or at least 20.00 m2 / g. In some embodiments, the particles comprising ZnO and / or a derivative thereof have a BET surface area of at most 250.00 m2 / g, or at most 225.00 m2 / g, or at most 200.00 m2 / g, or at most 180.00 m2 / g, or at most 165.00 m2 / g. In some preferred embodiments, the particles comprising ZnO and / or a derivative thereof have a BET surface area of between at least 10.00 and at most 250.00 m2 / g, or between at least 10.00 and at most 200.00 m2 / g, or between at least 15.00 and at most 180.00 m2 / g, or between at least 20.00 and at most 165.00 m2 / g.

[0128] In some embodiments, the particles comprising ZnO and / or a derivative thereof have an average pore volume of at least 0.100 cm3 / g. In some embodiments, the particles comprising ZnO and / or a derivative thereof have an average pore volume of at most 1.500 cm3 / g, or at most 1.300 cm3 / g, or at most 1.000 cm3 / g, or at most 0.750 cm3 / g, or at most 0.500 cm3 / g, or at most 0.250 cm3 / g. In some preferred embodiments, the particles comprising ZnO and / or a derivative thereof have an average pore volume of between at least 0.100 and at most 1.500 cm3 / g, or between at least 0.100 and at most 1.300 cm3 / g, or between at least 0.100 and at most 1.000 cm3 / g, or between at least 0.100 and at most 0.750 cm3 / g, or between at least 0.100 and at most 0.500 cm3 / g, or between at least 0.100 and at most 0.250 cm3 / g, or between at least 0.200 and at most 0.250 cm3 / g. It has been found that particles comprising ZnO and / or a derivative thereof having relatively larger pores are desired for subsequent treatment with other compounds, such as an activator as disclosed herein.

[0129] The particles comprising ZnO and / or a derivative thereof preferably mainly comprise mesopores and / or macropores. Mesopores are pores with a diameter typically ranging between 2 and 50 nm. Mesopores are intermediate in size between micropores (which typically have diameters less than 2 nanometers) and macropores (which typically have diameters greater than 50 nanometers).

[0130] The terms “average pore size” and “average pore diameter” are used herein interchangeably.

[0131] In some embodiments, the particles comprising ZnO and / or a derivative thereof have an average pore size of at least 1 nm, or at least 2 nm, or at least 3 nm, or at least 4 nm, or at least 5 nm. In some embodiments, the particles comprising ZnO and / or a derivative thereof have an average pore size of at most 150 nm, or at most 125 nm, or at most 100 nm, or at most 75 nm, or at most 50 nm. In some preferred embodiments, the particles comprising ZnO and / or a derivative thereof have an average pore size of between at least 1 and at most 150 nm, or between at least 1 and at most 125 nm, or between at least 1 and at most 100 nm, or between at least 1 and at most 75 nm, or between at least 2 and at most 75 nm, or between at least 3 and at most 75 nm, or between at least 4 and at most 75 nm, or between at least 5 and at most 75 nm, or between at least 5 and at most 50 nm.

[0132] The BET surface area, average pore volume, and / or average pore size of the particles comprising ZnO and / or a derivative thereof are determined by techniques known to the person skilled in the art as explained in the example section below.

[0133] In some preferred embodiments, the particles comprising ZnO and / or a derivative thereof have a Young’s modulus (E) of between at least 90.0 and at most 170.0 GPa, or between at least 90.0 and at most 160.0 GPa, or between at least 100.0 and at most 160.0 GPa, or between at least 110.0 and at most 160.0 GPa, or between at least 120.0 and at most 160.0 GPa. Young’s modulus (E) may be measured by any technique known to the person skilled in the art. For instance, the Young’s modulus (E) may be determined using a nanoindenter.

[0134] Advantageously, particles comprising ZnO and / or a derivative thereof as applied in the present invention and as defined herein have certain advantages as compared to particles comprising silica.

[0135] The catalyst particles prepared with a Zinc-containing catalyst support as defined herein are sufficiently stable to have a controlled fragmentation, and to avoid disintegration of the particles and the formation of polymer fines. The present zinc-containing particles and support made therefrom have the advantage that a greater number of reactive sites of the catalyst may be exposed during polymerization resulting in a more controlled size distribution and morphology of the resulting polymer particles.

[0136] It is preferred that the particles comprising ZnO and / or a derivative thereof which are comprised within the catalyst support of the invention comprise high amounts of ZnO. In accordance with the invention, the main component of the ZnO particles, based on the total weight of the particles, is ZnO. In some preferred embodiments, the particles therefore comprise at least 80.0 wt% of ZnO, or at least 82.5 wt%, or at least 85.0 wt%, or at least 87.5 wt%, or at least 90.0 wt%, or at least 92.5 wt%, or at least 95.0 wt%, or at least 97.5 wt%, or at least 99.0 wt% of ZnO thereof with wt% based on the total weight of the particles. In certain embodiments, the particles comprising ZnO and / or a derivative thereof essentially consist of ZnO. The term “essentially consisting of” as used herein intends to refer to particles wherein the amount of ZnO is at least 99.5 wt %, such as 99.9 wt%.

[0137] The measurement of the chemical composition of the particles is done by means of inductively coupled plasma optical emission spectroscopy (ICP-OES). The particles comprising ZnO and / or a derivative thereof are preferably free or essentially free from impurities, such as carbon contaminants.

[0138] In some embodiments, the particles comprising ZnO and / or a derivative thereof have a concentration of hydroxyl (-OH) groups of at least 0.1 to at most 1.0 mmol / g, based on the total weight of the particles. The concentration of hydroxyl (-OH) groups may be measured by any technique known to the person skilled in the art. For instance, a suitable method to determine the concentration of hydroxyl (-OH) groups includes Nuclear Magnetic Resonance (NMR) spectroscopy.

[0139] It has been found that the particles comprising ZnO and / or a derivative thereof are particularly useful for preparing a catalyst support, preferably for preparing a support for an olefin polymerization catalyst. Accordingly, the present also relates to the use of particles comprising zinc oxide (ZnO) as defined herein, for preparing a support for an olefin polymerisation catalyst, preferably for preparing a support for a metallocene-based olefin polymerization catalyst.

[0140] According to the present invention, the catalyst support may be treated or modified to optimize its surface properties and enhance its interaction with a catalyst component.

[0141] In some preferred embodiments, the particles comprising ZnO and / or a derivative thereof are at least partially impregnated with an activator. An “activator” as used herein in the context of the present invention refers to a substance capable of improving the activity and / or selectivity of a catalyst component). The activator may further partially control the rate and extent of olefin polymerization by promoting the formation of active species. The activator, as used herein, preferably is an aluminum-containing activator or a boron-containing activator.

[0142] Preferably, the activator is an organoaluminum compound such as an alumoxane. The term “alumoxane” and “aluminoxane” may be used interchangeably. In some embodiments, alumoxanes comprise oligomeric linear and / or cyclic alkyl alumoxanes. In a preferred embodiment, the organoaluminum compound is an aluminoxane compound of formula (A1) or (A2),

[0143] Ra-(AI(Ra)-O)x-AIRa2 (A1) for oligomeric, linear aluminoxanes; or

[0144] (-AI(Ra)-O-)y(A2) for oligomeric, cyclic aluminoxanes; wherein x is an integer between 1 and 40, and preferably between 10 and 20; wherein y is an integer between 3 and 40, and preferably between 3 and 20; and wherein each Rais independently selected from a Ci-salkyl, and preferably is a Ci-4alkyl, more preferably is methyl or ethyl. In some preferred embodiments, the organoaluminum compound is Methyl Alumoxane (MAO) or ethyl alumoxane.

[0145] In some preferred embodiments, the amount of activator is comprised between 20.0 wt% and 60.0 wt%, or between 20.0 wt% and 55.0 wt%, or between 20.0 wt% and 50.0 wt%, or between 25.0 wt% and 50.0 wt%, or between 25.0 wt% and 45.0 wt%, , with wt% based on the total weight of the catalyst support. Determining the amount of activator, relative to the total weight of the support, can be done by means of Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), as explained in the example section.

[0146] A catalyst support according to the invention comprises particles comprising ZnO and / or a derivative thereof, that is impregnated with an activator. When impregnating particles comprising ZnO and / or a derivative thereof with an activator as defined herein, the properties of the particles may be tailored. For example, it has been found that the total surface area of impregnated particles may be increased about two to three times compared to the nonimpregnated particles.

[0147] In certain embodiments, the catalyst support comprises at least 25.0 wt% of the particles as defined herein, preferably at least 30.0 wt%, at least 40.0 wt%, at least 50.0 wt%, at least 60.0 wt%, at least 70.0 wt%, at least 80.0 wt%, with wt% based on the total weight of the support.

[0148] In certain embodiments, the invention provides a zinc-containing catalyst support for an olefin polymerisation catalyst, preferably for a metallocene-based olefin polymerisation catalyst, wherein the support comprises: at least 50.0 wt%, based on the total weight of the support, of ZnO particles, wherein said particles comprise at least 80.0 wt% of zinc oxide (ZnO) with wt% based on the total weight of the particles; and wherein the ZnO-particles have an average particle size of between at least 2.0 and at most 100.0 pm, such as between 4.0 and 50.0 pm, or between 10.0 and 45.0 pm, preferably determined as explained in the example section, and between 20.0 wt% and 50.0 wt%, or between 25.0 wt% and 45.0 wt%, with wt% based on the total weight of the support, of an activator, preferably wherein the activator is an organoaluminum compound as defined herein.

[0149] In some embodiments, the catalyst support as defined herein has an average particle size of at least 2.0 pm, or at least 4.0 pm, or at least 5.0 pm, or at least 10.0 pm, or at least 15.0 pm, or at least 20.0 pm. In some embodiments, the catalyst support as defined herein has an average particle size of at most 100.0 pm, or at most 90.0 pm, or at most 80.0 pm, or at most 70.0 pm, or at most 50.0 pm. In some embodiments, the catalyst support as defined herein has an average particle size of between at least 2.0 and at most 100.0 pm, or between at least 2.0 and at most 90.0 pm, or between at least 2.0 and at most 80.0 pm, or between at least 4.0 and at most 80.0 pm, or between at least 4.0 and at most 70.0 pm, or between at least 4.0 and at most 50.0 pm, or between at least 10.0 and at most 45.0 pm. Average particle size may be determined by as explained in the example section with FIB SEM.

[0150] In some embodiments, the catalyst support as defined herein has an average particle size D50 of at least 2.0 pm, or at least 4.0 pm, or at least 5.0 pm, or at least 10.0 pm, or at least 15.0 pm, or at least 20.0 pm. In some embodiments, the catalyst support as defined herein has an average particle size D50 of at most 100.0 pm, or at most 90.0 pm, or at most 80.0 pm, or at most 70.0 pm, or at most 50.0 pm. In some embodiments, the catalyst support as defined herein has an average particle size D50 of between at least 2.0 and at most 100.0 pm, or between at least 2.0 and at most 90.0 pm, or between at least 2.0 and at most 80.0 pm, or between at least 4.0 and at most 80.0 pm, or between at least 4.0 and at most 70.0 pm, or between at least 4.0 and at most 50.0 pm, or between at least 10.0 and at most 45.0 pm. Average particle size D50 may be determined by a Laser diffraction method as explained in the example section.

[0151] In some embodiments, the catalyst support as defined herein has a BET surface area of at least 20.00 m2 / g, or at least 25.00 m2 / g, or at least 40.00 m2 / g. In some embodiments, the catalyst support as defined herein has a BET surface area of at most 750.00 m2 / g, or at most 600.00 m2 / g, or at most 450.00 m2 / g, or at most 300.00 m2 / g, or at most 275.00 m2 / g, or at most 250.00 m2 / g, or at most 200.00 m2 / g, or at most 150.00 m2 / g, or at most 100.00 m2 / g, or at most 85.00 m2 / g, or at most 80.00 m2 / g. In some embodiments, the catalyst support as defined herein has a BET surface area of between at least 20.00 and at most 750.00 m2 / g, or between at least 20.00 and at most 600.00 m2 / g, or between at least 20.00 and at most 450.00 m2 / g, or between at least 20.00 and at most 300.00 m2 / g, or between at least 20.00 and at most 275.00 m2 / g, or between at least 20.00 and at most 250.00 m2 / g, or between at least 20.00 and at most 200.00 m2 / g, or between at least 20.00 and at most 150.00 m2 / g, or between at least 20.00 and at most 100.00 m2 / g, or between at least 25.00 and at most 85.00 m2 / g, or between 30.0 and 82.5 m2 / g, or between at least 40.00 and at most 80.00 m2 / g. BET surface area may be determined as explained in the example section

[0152] In some embodiments, the catalyst support as defined herein has an average pore volume of at least 0.100 cm3 / g. In some embodiments, the catalyst support as defined herein has an average pore volume of at most 2.000 cm3 / g, or at most 1 .750 cm3 / g, or at most 1 .500 cm3 / g, or at most 1.400 cm3 / g, or at most 1 .300 cm3 / g, or at most 1 .200 cm3 / g, or at most 1.100 cm3 / g, or at most 1.000 cm3 / g, or at most 0.750 cm3 / g, or at most 0.500 cm3 / g, or at most 0.250 cm3 / g. In some embodiments, the catalyst support as defined herein has an average pore volume of between at least 0.100 and at most 2.000 cm3 / g, or between at least 0.100 and at most 1.750 cm3 / g, or between at least 0.100 and at most 1.500 cm3 / g, or between at least 0.100 and at most 1.400 cm3 / g, or between at least 0.100 and at most 1.300 cm3 / g, or between at least 0.100 and at most 1.200 cm3 / g, or between at least 0.100 and at most 1.100 cm3 / g, or between at least 0.100 and at most 1.000 cm3 / g, or between at least 0.100 and at most 0.750 cm3 / g, or between at least 0.100 and at most 0.500 cm3 / g, or between at least 0.100 and at most 0.250 cm3 / g. Average pore volume may be determined as explained in the example section.

[0153] In some embodiments, the catalyst support as defined herein has an average pore size of between at least 1 and at most 150 nm, or between at least 1 and at most 125 nm, or between at least 1 and at most 100 nm, or between at least 1 and at most 75 nm, or between at least 2 and at most 75 nm, or between at least 3 and at most 75 nm, or between at least 4 and at most 75 nm, or between at least 5 and at most 75 nm, or between at least 5 and at most 50 nm. Average pore size may be determined as explained in the example section.

[0154] In some embodiments, the catalyst support as defined herein has a Young’s modulus (E) of between at least 90.0 and at most 170.0 GPa, or between at least 90.0 and at most 160.0 GPa, or between at least 100.0 and at most 160.0 GPa, or between at least 110.0 and at most 160.0 GPa, or between at least 120.0 and at most 160.0 GPa.

[0155] In some preferred embodiments, the catalyst support has a concentration of Lewis Acid Sites (LAS) of between at least 15.0 pmol / g and at most 100.0 pmol / g, or between at least 15.0 pmol / g and at most 90.0 pmol / g, or between at least 15.0 pmol / g and at most 80.0 pmol / g, or between at least 15.0 pmol / g and at most 70.0 pmol / g, or between at least 15.0 pmol / g and at most 50.0 pmol / g, or between at least 20.0 pmol / g and at most 50.0 pmol / g, or between at least 30.0 pmol / g and at most 50.0 pmol / g. LAS may be determined as explained in the example section. The present invention further relates to (1 ) a method for the preparation of particles comprising zinc oxide and / or a derivative thereof, as defined herein, and (2) to a method for the preparation of a zinc-containing catalyst support as defined herein.

[0156] Therefore, in another aspect, the present invention relates to a method for the preparation of particles comprising zinc oxide, and / or a derivative thereof, preferably particles comprising zinc oxide and / or a derivative thereof, according to the present invention.

[0157] In some embodiments a method for the preparation of particles comprising zinc oxide comprises the steps of: a) forming a zinc-containing precipitate by preparing a solution comprising ZnO, and b) processing said solution into particles comprising ZnO and / or a derivative thereof.

[0158] Such zinc-containing precipitate may for instance be prepared by suspending a ZnO powder into a suitable solvent, such as e.g. water. Processing said solution into particles comprising ZnO and / or a derivative thereof may be done as described herein, e.g. using spray-drying.

[0159] In some embodiments such method comprises the steps of: a) forming a zinc-containing precipitate by preparing a solution comprising a zinc salt, a precipitating agent, and optionally a nucleating agent; and b) processing said solution into particles comprising ZnO and / or a derivative thereof.

[0160] In another aspect, the present invention also provides a method for the preparation of a zinc- containing catalyst support, preferably a zinc-containing catalyst support according to the present invention. In some embodiments such method comprises the steps of: a) forming a zinc-containing precipitate by preparing a solution comprising ZnO, and b) processing said solution into particles comprising ZnO and / or a derivative thereof; and c) treating said particles comprising ZnO and / or a derivative thereof with an activator, thereby obtaining a zinc-containing-catalyst support.

[0161] In some embodiments such method comprises the steps of: a) forming a zinc-containing precipitate by preparing a solution comprising a zinc salt, a precipitating agent, and optionally a nucleating agent; b) processing said solution into particles comprising ZnO and / or a derivative thereof; and c) treating said particles comprising ZnO and / or a derivative thereof with an activator, thereby obtaining a zinc-containing-catalyst support.

[0162] Zinc salts, precipitating agents and nucleating agents are preferably as defined herein below. It should be noted that (preferred) embodiments of the particles comprising zinc oxide and / or a derivative thereof, and the zinc-containing catalyst support according to the invention are respectively also (preferred) embodiments of the method for the preparation of particles comprising zinc oxide and / or a derivative thereof, or for the method for the preparation of a zinc-containing catalyst support according to the invention and vice versa. In addition, any advantages of particles comprising zinc oxide and / or a derivative thereof, and the zinc- containing catalyst support as disclosed herein equally apply to the method for the preparation of particles comprising zinc oxide and / or a derivative thereof, or for the method for the preparation of a zinc-containing catalyst support of the invention.

[0163] The first step, step a), in the above preparation methods thus involves the formation of a zinc- containing precipitate. A “zinc-containing precipitate”, as used herein, refers to a zinc-containing solid material formed from one or more substances that were initially dissolved in a solution. In some embodiments the solution of the present methods is formed by mixing a zinc salt, a precipitating agent, and optionally a nucleating agent in a suitable solvent. The formation of the zinc-containing precipitate may advantageously be independent of the mixing order. Hence, the sequence in which the components are mixed or combined may vary. The zinc salt, precipitating agent, and optional nucleating agent may be provided by any suitable means, e.g. by supplying said components to a suitable mixing device or vessel. Preferably, the zinc salt and optional nucleating agent are dissolved in the one or more solvents prior to addition of the precipitating agent.

[0164] Non-limiting examples of suitable solvents include aqueous solvents comprising water and / or one or more C1-C4 alcohols. When a subscript is used herein following a carbon atom, the subscript refers to the number of carbon atoms that the named group may contain. For example, Ci alcohol refers to an alcohol compound having 1 carbon atom. A C1-C4 alcohol refers to an alcohol compound comprising 1-4 carbon atoms. Said C1-C4 alcohol may comprise linear or branched groups. Non-limiting examples of suitable C1-C4 alcohols include methanol, ethanol, 1 -propanol, isopropanol, 1 -butanol, isobutanol, sec-butanol, and tert-butanol. The aqueous solvent may further comprise one or more surfactants. Non-limiting examples of suitable surfactants include sulfates, sulfonates, phosphates, and carboxylates.

[0165] In some preferred embodiments, the solution has a pH of between at least 4 and at most 9, or of between at least 5 and at most 9, or of between at least 6 and at most 9, or of between at least 7 and at most 9. The pH of the solution may control the rate of precipitation and may be used to control the morphology of the zinc-containing precipitate. Preferably, the pH of the solution remains essentially constant during the formation of the zinc-containing precipitate. The zinc-containing precipitate may be formed immediately after preparing the solution as described herein. In particular, the zinc salt and precipitating agent dissolved in the solvent may interact and / or react to form a solute with a different solubility. Once the solution can no longer dissolve the newly formed solute, it becomes saturated and small clusters of solute will aggregate to form an insoluble zinc-containing precipitate. Optionally, a nucleating agent may be added to promote the formation of aggregates. This has the advantage that a zinc-containing precipitate with a tunable size and / or morphology may be formed.

[0166] In some embodiments, the solution comprises a zinc salt : precipitating agent molar ratio of at least 1 : 1.2 to at most 1 :4, preferably a molar ratio of between 1 :2 and 1 :3.

[0167] In some embodiments, the solution comprises a zinc salt : nucleating agent molar ratio of at least 1 :0.05 to at most 1 :0.5, or at least 1 :0.25 to at most 1 :0.5.

[0168] In some embodiments, the zinc salt comprises a water-soluble zinc salt, and preferably is selected from the group consisting of zinc nitrate, zinc chloride, zinc acetate, zinc bromide, zinc iodide, zinc carbonate, zinc sulphate, zinc 2-ethyl hexanoate, zinc gluconate, zinc citrate, any hydrates thereof, and any mixtures thereof.

[0169] The term “hydrate” in the context of the zinc salt as defined herein generally refers to compounds in which the zinc salt is associated with one or more water molecules. For instance, suitable hydrates include hydrates of zinc nitrate, ZnNOs zFW, wherein z is a positive number, and zinc carbonate, ZnCCh nFW, wherein n is a positive number.ln some embodiments, the zinc salt comprises a mixed hydroxide wherein the zinc ion is bound to hydroxide ions with one or more other metal ions, such as cobalt or nickel.

[0170] In some embodiments, the precipitating agent comprises a water-soluble basic salt, and preferably is selected from the group consisting of hexamethylenetetramine, NaOH, urea, KOH, NH4OH, NaHCOs, (NH4)2CO3, and any mixtures thereof.

[0171] In some embodiments, the optional nucleating agent comprises a surfactant, preferably an anionic surfactant, a cationic surfactant, and / or a zwitterionic surfactant. Suitable non-limiting anionic surfactants are surfactants comprising a sulfate, sulfonate, phosphate, or carboxylate functional group. In some embodiments, the anionic surfactant is selected from the group consisting of ammonium lauryl sulfate, sodium dodecyl sulfate, sodium lauryl ether sulfate, sodium myreth sulfate, dioctyl sodium sulfosuccinate.

[0172] In some embodiments, the optional nucleating agent comprises a tricarboxylic acid compound, preferably selected from the group consisting of citric acid, citrate salt, isocitric acid, isocitrate salt, aconitic acid, aconitate salt, tricarballylic acid, tricarballylate salt, trimesic acid, trimesate salt, trimellitic acid, trimellitate salt, and mixtures thereof. In some embodiments, the optional nucleating agent comprises a cationic surfactant, preferably an alkylammonium salt of the Formula (NR2xH4-x)Y, wherein R2is a Ci-2oalkyl, x is an integer ranging from 1-4, and Y is a fluoride, chloride, bromide, or iodide.

[0173] In some embodiments, step a) in the above preparation methods, further comprises heating the solution to a temperature of between 100 °C and 180 °C, or between 110 °C and 170 °C, or between 120 °C and 160 °C. Heating of the solution may change the solubility of the zinc salt, the precipitating agent, the optional nucleating agent, the zinc-containing precipitate, and any intermediates in the solution. This has the advantage that the formation of zinc-containing precipitate may be accelerated and even improved.

[0174] In a next step, step b), of the preparation methods of the invention, the solution comprising the zinc-containing precipitate is processed into particles comprising ZnO and / or a derivative thereof.

[0175] In some embodiments, processing of the solution into particles comprising ZnO and / or a derivative thereof in step b) of the present methods comprises separating the zinc-containing precipitate from said solution. Separation of the zinc-containing precipitate from the solution may be carried out according to techniques known in the art. For example, the solution comprising the zinc-containing precipitate may be filtered, centrifuged, or decanted. Optionally, the separated zinc-containing precipitate may be washed with a suitable solvent such as water and / or a C1-C4 alcohol to remove contaminants.

[0176] In some embodiments, processing further involves drying said separated precipitate, preferably at a temperature of between 40 and 120 °C. Drying of the separated zinc-containing precipitate may be carried out according to techniques known in the art. For example, the separated zinc-containing precipitate may be transferred to a convection oven or a vacuum oven for at least 2 hours, or at least 4 hours, or at least 8 hours, or at least 12 hours, or at least 24 hours. Said convection oven or vacuum oven may be operated at a temperature between 30 °C and 80 °C, preferably between 40 °C and 60 °C.

[0177] In some embodiments, processing further involves the step of calcining said separated precipitate, which may have been dried; preferably wherein calcining is performed at a temperature of at least 200 °C to at most 800 °C, and preferably during 2 to 8 hours. Calcining of the separated, and optionally dried, zinc-containing precipitate may be carried out according to techniques known in the art. For example, the separated zinc-containing precipitate may be transferred to a furnace or kiln configured for calcination. The furnace or kiln may be equipped with suitable temperature control means and an inlet for providing an inert gas. The controlled temperature and atmosphere may be used to regulate the calcination conditions. The calcination process involves gradually heating the separated zinc-containing precipitate to a desired temperature, which may remove volatile substances, decompose compounds, or induce phase transformations in the precipitate.

[0178] In some embodiments, a separated zinc-containing precipitate is calcined at a temperature of at least 200 °C, or at least 250 °C, or at least 300 °C, or at least 400 °C. In some embodiments, a separated zinc-containing precipitate is calcined at a heating rate of at least 1.0 °C / min, or at least 1 .5 °C / min, or at least 2.0 °C / min. In some embodiments, a separated zinc-containing precipitate is calcined for at least 1 hour, or at least 2 hours, or at least 3 hours, or at least 4 hours, or at least 6 hours at a desired temperature.

[0179] In some embodiments, processing of the solution into particles comprising ZnO and / or a derivative thereof in step b) of the present methods comprises subjecting the solution of step a) to spray drying, drying, flash drying, or any combinations thereof. Preferably, the solution is subjected to spray drying. It has been found that such treatments may advantageously provide a continuous process for producing particles comprising ZnO and / or a derivative thereof of desired properties, including shape, particle size, and particle size distribution.

[0180] The term “spray drying”, as used herein, has a well-accepted meaning within the state of the art and refers to a process for converting a liquid or slurry into a dry powder. The spray drying process described herein may involve drying a feed of the solution comprising the zinc- containing precipitate by atomizing it into small droplets, which can then be rapidly dried by contact with a heated gas stream in a suitable drying chamber. As the droplets travel through the drying chamber, the moisture evaporates, leaving behind dried particles that are collected as powder or granules. In the context of the present invention, spray drying may advantageously be used to convert the solution comprising the zinc-containing precipitate to particles comprising ZnO and / or a derivative thereof of desired properties.

[0181] Spray drying may be performed in a suitable spray drying apparatus. For instance, said apparatus may comprise a pumping means, an atomization means, a gas inlet, and a drying chamber, wherein the pumping means is connected to the atomization means; and the atomization means and the gas inlet are connected to the drying chamber. The apparatus may further comprise one or more suitable separation means, such as a cyclone separator, to remove residual solvent; wherein the one or more suitable separation means is connected to the drying chamber. Non-limiting examples of an atomization means include a rotary or nozzle atomizer. The solution may be provided to said atomization means by a pumping means, such as a fluid pump. In some embodiments, spray drying of the solution as defined herein is carried out in the presence of a heated gas, preferably air, nitrogen, or a noble gas, preferably at a spray pressure of between 0.1 and 1.0 MPa, or between 0.1 and 0.8 MPa, or between 0.1 and 0.5 MPa, or between 0.1 and 0.2 MPa. This has the advantage that the particles may be dried more rapidly.

[0182] In some embodiments, the heated gas has a flow rate of at least 0.001 m3 / min, such as at least 0.01 m3 / min, such as between 0.01 and 1.0 m3 / min, or between 0.01 and 0.9 m3 / min, or between 0.01 and 0.8 m3 / min, or between 0.01 and 0.7 m3 / min, or between 0.01 and 0.6 m3 / min.

[0183] In some embodiments, the heated gas has a temperature of between at least 100 °C and at most 300 °C, or between at least 100 °C and at most 250 °C, or between at least 120 °C and at most 250 °C, or between at least 120 °C and at most 220 °C, or between at least 150 °C and at most 220 °C, or between at least 150 °C and at most 200 °C.

[0184] In some embodiments, the solution is contacted with the heated gas in a drying chamber, and the solution is provided to said drying chamber at a flow rate of between 0.1 and 1000.0 L / h, or between 0.2 and 1000.0 L / h, or between 1.0 and 1000.0 L / h, or between 1.5 and 800.0 L / h, or between 50.0 and 750.0 L / h, or between 100.0 and 750.0 L / h, or between 250.0 and 750.0 L / h.

[0185] In some embodiments, the concentration of the precipitate in the solution as defined herein is between 10.0 and 500.0 g / L, or between 10.0 and 450.0 g / L, or between 10.0 and 400.0 g / L, or between 10.0 and 350.0 g / L, or between 20.0 and 350.0 g / L, or between 30.0 and 350.0 g / L, or between 40.0 and 350.0 g / L, or between 50.0 and 350.0 g / L.

[0186] In an example, spray drying of the solution as defined herein may be carried out at a temperature of between 120 and 300 °C, at a solution feed rate of 0.18 to 1 .8 L / h, at a pressure of 0.5 to 0.8 MPa, at a concentration of the precipitate in the solution of between 50 and 500 g / L, and at a heated gas (e.g. air, nitrogen) flow rate of 0.0014-0.014 m3 / min.

[0187] The obtained particles comprising ZnO and / or a derivative thereof may be subsequently treated with an activator, preferably as defined herein, to obtain a zinc-containing catalyst support of the invention. Treatment with such activator may be carried out by techniques known within the art. For example, the activator may be at least partially deposited on the particles comprising ZnO and / or a derivative thereof by means of impregnation, (co- )precipitation, adsorption, or chemical vapor deposition.

[0188] In some embodiments, the particles comprising ZnO and / or a derivative thereof are treated with the activator in a step c) by mixing a mixture of the particles and an activator solution for at least 1 hour to at most 24 hours; preferably at a temperature of between 100 °C and 180 °C, or between 110 °C and 170 °C, or between 120 °C and 160 °C; and preferably under an inert atmosphere, more preferably a nitrogen atmosphere.

[0189] In an example , the amount of activator as defined herein in the mixture is comprised between at least 20.0 wt% and at most 50.0 wt% of activator, with wt% the total weight of the mixture. It is preferred that the amount of particles comprising ZnO used to prepare the support is at least 50.0 wt%, wherein wt% is based on the total weight of the support, and preferably is at least 60.0 wt% or at least 70.0 wt%.

[0190] Another aspect of the present invention relates to a zinc-containing catalyst support that is obtained or obtainable by carrying out a method for the preparation of a zinc-containing catalyst support according to the invention.

[0191] In another aspect, the present invention relates to a catalyst composition, which comprises a zinc-containing catalyst support according to the invention, or obtained or obtainable by carrying out a method according to the invention; and a catalyst component.

[0192] The catalyst component may be a Ziegler-Natta catalyst, a Phillips catalyst, a metallocene catalyst, a phosphinimine catalyst, a constrained geometry catalyst, and combinations thereof. In an example, the catalyst component is a metallocene catalyst.

[0193] In some preferred embodiments, the catalyst component is at least partially immobilized on the catalyst support. In other words, said active catalytic species may be at least partially anchored, linked, or attached onto the solid zinc-containing catalyst support as disclosed herein. Hence, said support may advantageously provide the catalyst component with improved structural stability and facilitate interaction with reactants. The catalyst component may be immobilized to the catalyst support by any method known to the person skilled in the art, such as impregnation, (co-)precipitation, adsorption, or chemical vapor deposition. In particular, the catalyst component may be introduced in the form of a solution, suspension, or vapor, allowing it to interact with the support and adhere to its surface.

[0194] In some embodiments, the catalyst composition comprises between at least 0.001 and at most 5.0 wt%, or between at least 0.005 and at most 5.0 wt%, or between at least 0.01 and at most 5.0 wt%, or between at least 0.01 and at most 4.5 wt%, or between at least 0.01 and at most 4.0 wt%, of the catalyst component, with wt% based on the total weight of the catalyst composition.

[0195] In some preferred embodiments, the catalyst composition comprises up to 20.0 wt%, or up to 17.0 wt%, or up to 15.0 wt%, or up to 10.0 wt%, of a metal, preferably wherein the metal is selected from the group consisting of Al, Zr, Hf, Ti. The amount of such metal(s) may be determined by means of ICP-AES as described herein in the methodology section.

[0196] In some preferred embodiments, the catalyst composition comprises between 1.0 and 12.0 wt%, or between 2.0 and 11.0 wt%, or between 3.0 and 10.0 wt%, of aluminum, with wt% based on the total weight of the catalyst composition. The amount of aluminum may be determined by means of ICP-AES as described herein in the methodology section.

[0197] In some preferred embodiments, the catalyst composition comprises between 0.001 and 5.0 wt%, or between 0.01 and 5.0 wt%, or between 0.01 and 4.0 wt%, or between 0.01 and 1.0 wt%, of zirconium, with wt% based on the total weight of the catalyst composition. The amount of zirconium may be determined by means of ICP-AES as described herein in the methodology section.

[0198] In an example, the catalyst composition comprises between 1.0 and 12.0 wt% of Al and between 0.001 and 5.0 wt% of Zr. In another example, the catalyst composition comprises between 2.0 and 11.0 wt% of Al and between 0.01 and 4.0 wt% of Zr. In another example, the catalyst composition comprises between 3.0 and 10.0 wt% of Al and between 0.01 and 1.0 wt% of Zr.

[0199] In some embodiments, the catalyst composition is characterized by one or more of the following features. In certain embodiments, the catalyst composition according to the invention has an average particle size of between at least 2.0 and at most 100.0 pm, or between at least 2.0 and at most 90.0 pm, or between at least 2.0 and at most 80.0 pm, or between at least 4.0 and at most 80.0 pm, or between at least 4.0 and at most 70.0 pm, or between at least 4.0 and at most 50.0 pm. Average particle size may be determined as explained in the example section.

[0200] In certain embodiments, the catalyst composition according to the invention has a BET surface area of between at least 20.0 and at most 800.0 m2 / g, or between at least 20.0 and at most 750.0 m2 / g, or between at least 20.0 and at most 700.0 m2 / g, or between at least 20.0 and at most 650.0 m2 / g, or between at least 20.0 and at most 600.0 m2 / g, or between at least 20.0 and at most 550.0 m2 / g, or between at least 20.0 and at most 500.0 m2 / g, or between at least 30.0 and at most 450.0 m2 / g, between 30 and 200 m2 / g. BET surface area may be determined as explained in the example section.

[0201] In certain embodiments, the catalyst composition according to the invention has an average pore volume of between at least 0.100 and at most 2.000 cm3 / g, or between at least 0.100 and at most 1.750 cm3 / g, or between at least 0.100 and at most 1.500 cm3 / g, or between at least 0.100 and at most 1.400 cm3 / g, or between at least 0.100 and at most 1.300 cm3 / g, or between at least 0.100 and at most 1.200 cm3 / g, or between at least 0.100 and at most 1.100 cm3 / g, or between at least 0.100 and at most 1.000 cm3 / g. Average pore volume may be determined as explained in the example section.

[0202] In certain embodiments, the catalyst composition according to the invention has a concentration of Lewis acid sites (LAS) of between at least 5.0 pmol / g and at most 80.0 pmol / g, or between at least 5.0 pmol / g and at most 75.0 pmol / g, or between at least 5.0 pmol / g and at most 70.0 pmol / g, or between at least 5.0 pmol / g and at most 65.0 pmol / g, or between at least 5.0 pmol / g and at most 60.0 pmol / g, or between at least 5.0 pmol / g and at most 55.0 pmol / g, or between at least 5.0 pmol / g and at most 50.0 pmol / g. LAS may be determined as explained in the example section.

[0203] In certain embodiments, the catalyst composition according to the invention has an average pore size of between at least 1 nm and at most 50 nm, or between at least 1 nm and at most 45 nm, or between at least 1 nm and at most 40 nm, or between at least 1 nm and at most 35 nm, or between at least 1 nm and at most 30 nm, or between at least 1 nm and at most 25 nm, or at least 1 nm and at most 20 nm, or between at least 1 nm and at most 15 nm. Average pore size may be determined as explained in the example section.

[0204] In an example, a catalyst composition according to the invention has one or more of the following properties:

[0205] (i) BET surface area of between 20.0 and 750.0 m2 / g, or between 30.0 and 200.0 m2 / g; and / or

[0206] (ii) an average pore volume of between 0.100 and 2.000 cm3 / g, or between 0.100 and 1.000 cm3 / g, and / or

[0207] (iii) an average pore size of between 1 nm and 50 nm, or between 1 nm and 15 nm.

[0208] The BET surface area, average pore volume, and average pore size of the catalyst composition may be determined by techniques known to the person skilled in the art as explained in the example section below.

[0209] In some embodiments, the catalyst composition may further comprise a co-catalyst. Preferably, said co-catalyst is selected from the group consisting of an organoaluminium compound, an organoboron or organoborate compound, an ionizing ionic compound, and any combinations thereof.

[0210] In some embodiments, the co-catalyst is an organoaluminium represented by the formula AIR1X, wherein each R1is the same or different and is selected from the group consisting of halogens, alkoxy, and alkyl, preferably halogens, Ci-i2alkyl , and Ci-i2alkoxy, and x is an integer from 1 to 3. For instance, the co-catalyst is an organoaluminium selected from the group consisting of trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminum chloride, and mixtures thereof. A preferred example is triethylaluminum (TEA).

[0211] In another aspect, the present invention relates to a method for the preparation of a catalyst composition, preferably a catalyst composition according to the invention. The method preferably comprises the step of forming a suspension, wherein the suspension comprises (a) a zinc-containing catalyst support, preferably a zinc-containing catalyst support according to the invention; (b) a catalyst component, preferably a catalyst component as defined herein. Optionally the suspension may also contain a co-catalyst, preferably as defined herein.

[0212] In some embodiments, the weight ratio of catalyst support: catalyst component is at least 1 :70, or at least 1 :80, or at least 1 :90, or at least 1 :100, or at least 1 :110, or at least 1 :120, or at least 1 : 130, or at least 1 : 140, or at least 1 : 150.

[0213] The formation of the suspension may advantageously be independent of the mixing order of the support, the catalyst component, and the optional co-catalyst. Hence, the sequence in which the components are mixed or combined may vary. The zinc-containing catalyst support, catalyst component, and optional co-catalyst may be provided by any suitable means, e.g. by supplying said components to a suitable mixing device or vessel. Preferably, the catalyst component is dissolved in a solvent prior to addition of the zinc-containing catalyst support, and optional co-catalyst. Non-limiting examples of suitable solvents include hydrocarbon solvents such as aliphatic, cycloaliphatic, and aromatic hydrocarbons. Preferably, the solvent is selected from the group consisting of toluene, ethylbenzene, p-xylene, m-xylene, hexane, heptane, cyclohexane, and mixtures thereof.

[0214] The present invention further relates to a catalyst composition obtained or obtainable by carrying out the method for the preparation of a catalyst composition according to the present invention.

[0215] Another aspect of the present invention relates to an olefin polymerization process, wherein use is made of particles comprising ZnO and / or a derivative thereof according to the invention, and / or a catalyst support according of the invention, and / or a catalyst composition according to the invention .

[0216] In some embodiments of the invention, an olefin polymerization process is provided, comprising the step of polymerizing an olefin monomer, such as ethylene or propylene, optionally hydrogen, optionally a diluent, and optionally one or more C2-20, or preferably C2-10 olefin comonomers, in the presence of at least one catalyst composition according to any one of the embodiments of the invention, or obtained or obtainable by carrying out a method according to the invention.

[0217] The term “olefin” is well known in the art, and refers herein to molecules composed of carbon and hydrogen, containing at least one carbon-carbon double bond Throughout the present application the terms “olefin polymer”, "polyolefin" and "polyolefin polymer" may be used synonymously. Examples of suitable olefin monomers include for instance ethylene and propylene.

[0218] As used herein, the term “comonomer” refers to olefin comonomers which are suitable for being polymerized with an olefin monomer. The comonomer if present is different from the olefin monomer and chosen such that it is suited for copolymerization with the olefin monomer. Comonomers may comprise but are not limited to aliphatic C2-20, or preferably C2-C10 olefins. Examples of aliphatic olefins comonomers for polymerization according to the present invention include for instance ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1 -pentene, 1-hexene, 1 -octene, and 1 -decene.

[0219] Suitable polymerization processes according to the invention include homopolymerization as well as copolymerization processes. Examples of copolymers which can be prepared according to the invention include for instance random copolymers of propylene and ethylene, ethylenebutene copolymers, ethylene-hexene copolymers, ethylene-octene copolymers, or heterophasic copolymers of propylene and ethylene.

[0220] In some preferred embodiments, the polymerization process is performed in slurry phase or gas phase.

[0221] The polymerization can be carried out batchwise or in a continuous process. In a preferred embodiment of the present invention, the polymerization is carried out in a continuous process. The term “continuous” means a system that operates without interruption or cessation. For example, a continuous process to produce a polymer would be one where the reactants are continually introduced into one or more reactors and polymer product is continually withdrawn. By this it is meant herein that the reactors, when operating, are run in continuous mode, that is at least one feed stream is predominantly fed continuously to the reactor, while at least one stream is predominantly withdrawn continuously.

[0222] The term "slurry" or "polymerization slurry" or "polymer slurry", as used herein refers to substantially a multi-phase composition including at least polymer solids and a liquid phase. The solids may include the catalyst composition as provided herein, and polymerized (comonomer.

[0223] In some embodiments, the liquid phase comprises a diluent. As used herein, the term “diluent” refers to any organic diluent, which does not dissolve the synthesized polyolefin. As used herein, the term “diluent” refers to diluents in a liquid state, liquid at room temperature and preferably liquid under the pressure conditions in the loop reactor. Suitable diluents comprise but are not limited to hydrocarbon diluents such as aliphatic, cycloaliphatic, and aromatic hydrocarbon solvents, or halogenated versions of such solvents. Preferred solvents are C12 or lower, straight chain or branched chain, saturated hydrocarbons, C5 to C9 saturated alicyclic or aromatic hydrocarbons or C2 to Ce halogenated hydrocarbons. Non-limiting illustrative examples of solvents are butane, isobutane, pentane, hexane, heptane, cyclopentane, cyclohexane, cycloheptane, methyl cyclopentane, methyl cyclohexane, isooctane, benzene, toluene, xylene, chloroform, chlorobenzenes, tetrachloroethylene, dichloroethane and trichloroethane, preferably isobutane or hexane.

[0224] The polymerization can also be performed in gas phase, under gas phase conditions. The term "gas phase conditions" as used herein refers to temperatures and pressures suitable for polymerizing one or more gaseous phase olefins to produce polymer therefrom.

[0225] In certain embodiments, the polymerization steps may be performed at a temperature from 20 °C to 125 °C, preferably from 40 °C to 110 °C, more preferably from 40 °C to 100 °C and most preferably from 50 °C to 100 °C.

[0226] In certain embodiments, when carried out under slurry conditions, the polymerization steps may be performed at a pressure from about 20 bar to about 100 bar, preferably from about 30 bar to about 50 bar, and more preferably from about 37 bar to about 45 bar.

[0227] Another aspect of the present invention relates to an olefin polymer obtainable or obtained by carrying out an olefin polymerization process according to the invention. In some embodiments, said olefin polymer is polyethylene. In some embodiments, said olefin polymer is polypropylene.

[0228] In some embodiments, the olefin polymer obtained in accordance with the process of the invention comprises remaining amounts of catalyst composition according to the invention and / or fragments thereof. In some embodiments, the amount of catalyst composition and / or fragments thereof comprised within the polymer is lower than 2000 ppm, such as lower than 1500 ppm, or lower than 1250 ppm, or lower than 1000 ppm. Catalyst amounts may be measured by using ICP-AES spectroscopy as described herein in the methodology section.

[0229] In some embodiments, the polymer as defined herein contains residual amounts of zinc, which may be present in an amount of up to 500 ppm, such as up to 250 ppm, or up to 150 ppm. Residual zinc can be determined in the polymer by means of ICP-AES as described herein.

[0230] After the polymer is produced, it may be processed into various articles. Such articles may include but are not limited to articles such as films, sheets, caps and closures, bottles, cups, fibers, yarns, pipes, etc.

[0231] The present invention therefore also encompasses an article comprising an olefin polymer as defined herein, or obtainable or obtained by carrying out a polymerization processes according to the invention.

[0232] The present invention further relates to the use of particles comprising ZnO and / or a derivative thereof according to the invention, or obtained or obtainable by carrying out the method for the preparation of particles comprising ZnO and / or a derivative thereof according to the invention, for preparing a catalyst support. Preferably such catalyst support is a support for an olefin polymerization catalyst. The present invention also relates to the use of particles comprising ZnO and / or a derivative thereof according to the invention, or obtained or obtainable by carrying out the method for the preparation of such particles according to the invention, in an olefin polymerization process for preparing an olefin polymer, and preferably in a metallocene- catalysed olefin polymerization process.

[0233] The present invention further also relates to the use of a zinc-containing catalyst support according to the invention, or obtained or obtainable by carrying out a method for the preparation of a zinc-containing catalyst support according to the invention, for preparing an olefin polymerization catalyst. The polymerization catalyst may be a Ziegler-Natta catalyst, a Phillips catalyst, a metallocene catalyst, a phosphinimine catalyst, a constrained geometry catalyst, and combinations thereof. In certain preferred embodiments, such the polymerization catalyst is a metallocene-based olefin polymerization catalyst.

[0234] Particles comprising ZnO and / or a derivative thereof, and a zinc-containing catalyst support of the invention can be particularly useful as catalyst support in an olefin polymerization process as defined herein.

[0235] The present invention thus also relates to the use of particles comprising zinc oxide (ZnO) and / or a derivative thereof, preferably as defined herein, in an olefin polymerization process for preparing an olefin polymer, and preferably in metallocene-catalysed olefin polymerization process. The present invention also relates to the use of a zinc-containing catalyst support according to the invention, or obtained or obtainable by carrying out a method according to the invention for the preparation of a zinc-containing catalyst support, in a polymerization process for preparing an olefin polymer, preferably an olefin polymerization process as defined herein. The present invention further also relates to the use of a catalyst composition according to the present invention, or obtained or obtainable by carrying out a method according to the invention for the preparation of a catalyst composition, in an olefin polymerization process as defined herein. The present invention thus also relates to a methods for preparing a polyolefin comprising the step of polymerization an olefin the presence of a catalyst composition according to the present invention, or obtained or obtainable by carrying out a method according to the invention.

[0236] METHODOLOGY

[0237] The following test methods were used.

[0238] Particle-related methods

[0239] • Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM)

[0240] Average particle size, particle size distribution, and particle morphology of particles comprising zinc oxide (ZnO) were determined herein using Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM) on a FEI Helios Nanolab G3 instrument operating at 0.1 nA and 2 kV for imaging and 80 pA and 30 kV for cutting. Samples were loaded on Al stubs with carbon tape. The external morphologies were imaged by collecting secondary electrons (SE) with a through-the-lens detector (TLD). Cross-sections of the particles were imaged by collecting back scattered electrons (BSE) with the TLD detector. Before removing half of the material with Ga FIB under an angle of 52°, a layer of Pt was deposited over the particle via FIB-assisted Pt deposition. After cleaning the exposed cross-sections with precision milling, discrete, isolated particles were selected. Typically, the particle size diameter of around 100 particles is measured to calculate the average particle size and size distribution.

[0241] • D50, D10, and D90 Particle Size Determination

[0242] The D50 is defined as the particle size for which fifty percent by weight of the particles has a size lower than the D50.

[0243] The D10 is defined as the particle size for which ten percent by weight of the particles has a size lower than the D10.

[0244] The D90 is defined as the particle size for which nighty percent by weight of the particles has a size lower than the D90. The span can then be calculated as follows: (D90-D10) / D50

[0245] Measurement of the D10, D50, D90 particle sizes can be made according to the International Standard ISO 13320:2009 ("Particle size analysis -Laser diffraction methods). The D10, D50, D90 particle sizes may be measured by laser diffraction analysis on a Malvern type analyzer after having put the supported catalyst in suspension in cyclohexane. Suitable Malvern systems include the Malvern 2000, Malvern MasterSizer (such as MasterSizer S), Malvern 2600 and Malvern 3600 series. Such instruments together with their operating manual meet or even exceed the requirements set-out within the ISO 13320:2009 Standard. The Malvern MasterSizer (such as MasterSizer S) may also be useful as it can more accurately measure the D50 towards the lower end of the range, by applying the theory of Mie, using appropriate optical means.

[0246] • Particle Size Analyser

[0247] Average particle size, particle size distribution, and particle morphology of catalyst composition were determined by laser light scattering, using a CILAS 1064L particle size analyzer, as supplied by CILAS. In the laser light scattering technique, the size of particles in powders, suspensions and emulsions may be measured using the diffraction of a laser beam, based on an application of Fraunhofer and Mie theory. Such a machine provides measurements and a plot of the cumulative percentage by volume of particles having a size, referred to in the art as the ‘equivalent spherical diameter’ (e.s.d), less than given e.s.d values. The mean particle size D50 is the value determined in this way of the particle e.s.d at which there are 50% by volume of the particles which have an equivalent spherical diameter less than that D50 value. The D10 value is the value at which 10% by volume of the particles have an e.s.d less than that D10 value. The D90 value is the value at which 90% by volume of the particles have an e.s.d less than that D90 value.

[0248] • Energy-Dispersive X-ray (EDX) Spectroscopy

[0249] The distribution of an activator on particles comprising zinc oxide (ZnO particles) or a catalyst component on said particles was determined by means of Energy-dispersive X-ray spectroscopy (EDX). EDX elemental maps of the cross-section were collected with an Oxford instruments Silicon Drift Detector X-Max energy dispersive spectroscope. For the analysis of the activator distribution, an acceleration voltage of 15 kV was used.

[0250] • X-ray Diffraction (XRD)

[0251] The crystal structure of the ZnO particles was determined by X-ray Diffraction (XRD). XRD patterns of the particles were recorded on a Bruker D2 PHASER diffractometer with CoKa radiation between 20=20-85° to identify the crystal phases. Nitrogen (N2) Physisorption

[0252] The Brunauer-Emmett-Teller (BET) surface area, average pore volume, average pore size, and average pore size distribution of particles, for instance ZnO particles, particles of the catalyst support, or particles of the catalyst composition, was determined by means of nitrogen (N2) physisorption according to ISO 9277:2022. Experiments were conducted at -196.15 °C using a TriStar II Plus instrument. The specific surface area of a particle may be estimated from the amount of nitrogen adsorbed in relationship with its pressure, at the boiling temperature of liquid nitrogen under normal atmospheric pressure. The observations are interpreted following the model of Brunauer, Emmett and Teller (BET Method). The desorption branch of the isotherm was used to determine the BET surface area, mesopore volumes (2-300 nm range), and Barret- Joyner-Halenda (BJH) pore size distributions.

[0253] • Lewis Acidity of the Particles (LAS : Lewis Active Sites)

[0254] The concentration of Lewis Acid Sites (LAS) of particles as defined herein, for instance ZnO particles, particles of the catalyst support, or particles of the catalyst composition, was determined by Fourier Transform Infrared Spectroscopy (FT-IR) and pyridine FT-IR spectroscopy. Experiments were conducted on a PerkinElmer 2000 instrument equipped with a DTGS KBr detector using 32 scans per spectrum from 1200 to 4000 cm-1and 0.482 cm-1resolution. Samples were prepared inside an N2 glovebox using a PIKE Technologies hydraulic press, with a force of 2.5 ton, resulting in pressed pellets (between 4 - 9 mg / 7 mm diameter) held in position by a stainless-steel collar. In the glovebox, the pellets were placed inside a well- sealed IR-cell capable of switching between vacuum and probe molecule vapor / gas. No drying treatment was performed since all samples were stored and prepared in an inert and dry atmosphere. For pyridine FT-IR spectroscopy measurements, pyridine was adsorbed for 30 min, and spectra taken every 5 min. After 30 min of evacuation, temperature-programmed desorption (TPD) (5 °C / min ramp to 250 °C) under vacuum was applied to remove all physisorbed pyridine, and spectra were taken every 10 °C till 150 °C. The acidity was quantified with the spectrum that was taken after 20 min of desorption at 150 °C. Spectra were taken after each pulse.

[0255] (1) _ A * 103LAS=~ 4 T "

[0256] •4o * P

[0257] Equation 1 , derived from Beer’s law, was used to quantify the concentration of Lewis acid sites CLAS (pmol / g) of the samples analysed with pyridine FT-IR spectroscopy. A (cm-1) represents the integral under the curve delimited by d<5 (cm-1). This area was obtained by simple abstraction of the high vacuum IR spectrum from the spectrum taken after 20 min desorption at 150 °C using the pyridine vibration at 1453 cm-1. The apparent integral adsorption coefficient Ao at this wavenumber is 2.22. The effective cross-section p (mg / cm2) is represented by the mass of the pallet (mg) per area of the pallet (cm2) through which the beam is sent.

[0258] • Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES)

[0259] The chemical composition of particles as defined herein, for instance ZnO particles, particles of the catalyst support, or particles of the catalyst composition was determined by means of Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). The spectrometer used was ICP-AES ARCOS, by Spectro.

[0260] The determination of elements was carried out by nebulization of the solution in an argon plasma, measurement of the intensities of the most sensitive and interference-free emission lines and comparison of these intensities with those of calibration solutions (external calibration method).

[0261] Preparation of the solution to be analyzed (test solution): Under an inert atmosphere (in a glove box), about 0.3 g of particles were added into a platinum crucible and 3 to 5 mL of isopropyl alcohol were added to "deactivate" the particles. The mixture was heated to dryness in a sand bath (30 minutes). The platinum crucible was placed in an oven at 600 °C for 10 minutes. After cooling, Milli-Q® deionized water was added to impregnate all the ashes, and 1 mL of concentrated HCI (Merck HCI 32% v / v) and concentrated HF (Merck HF 48% v / v) were added. The crucible was placed in a sand bath, and Milli-Q® deionized water was added to mix the content of the crucible. After 24 h, 1 mL of concentrated HCI, 0.5 mL of concentrated HF and Milli-Q® deionized water were added while agitating the mixture under heat to achieve full dissolution. After cooling the mixture was transferred to a 50 mL polypropylene tube and the volume made up to 50 mL with Milli-Q® deionized water. The test solutions were then diluted 25 times ensuring that 2% HCI / HF1 % medium was maintained.

[0262] Preparation of calibration standards and control solutions: Standard solutions were prepared by dilution of commercial single-element solutions of certified concentrations. The standard solutions were prepared by transferring the required volume of the certified solution to a 50 mL polypropylene tube, then rinsing the sides of the tube with Milli-Q® deionized water, and adding 1 mL of concentrated HCI and 0.5 mL of concentrated HF per 50 mL to obtain the same acid content in solution as in the sample solutions, and finalizing the dilution with Milli-Q® deionized water. Control solutions were prepared by dilution of commercial multi-element solutions of certified concentrations. The presence of other elements in solution allowed verification of the presence / absence of possible interferences.

[0263] Expression of results for Zr and Al contents: The content (in ppm) of the element measured in the sample was calculated as follows:

[0264] Concentration in mg / 1 of the element in solution x Volume (50 mL) x Dilution factor Mass g)

[0265] The Limit of Quantification (LOQ) was calculated for each element from 10 blank measurements:

[0266] LOQ in solution (mg / l) = standard deviation of 10 replicates of the blank x 10

[0267] LQ in solution x Volume (50 mL) x Dilution factor LOQ in sample (ppm) = - — - J Mass (g)

[0268] • Spray Drying

[0269] Spray drying was performed in a BUCH I B-290 acid-resistant mini spray dryer equipped with a standard 1.4 mm in diameter spray nozzle tip, 2.2 mm nozzle cap, and a drying chamber.

[0270] Polymer-related methods

[0271] • Molecular Weight, Molecular Distribution

[0272] The molecular weight (Mn(number average molecular weight), Mw(weight average molecular weight) and molecular weight distributions D (Mw / Mn), D’ (Mz / Mw), and Mz / Mnwere determined by Size Exclusion Chromatography (SEC) and in particular by IR-detected Gel Permeation Chromatography (GPC) at high temperature (145 °C). Briefly, a GPC-IR5MCT from Polymer Char was used: 8 mg polymer sample was dissolved at 160 °C in 8 mL of trichlorobenzene stabilized with 1000 ppm by weight of butylhydroxytoluene (BHT) for 1 hour (h). Injection volume: about 400 pl, automatic sample preparation and injection temperature: 160 °C. Column temperature: 145 °C. Detector temperature: 160 °C. Column set: two Shodex AT-806MS (Showa Denko) and one Styragel HT6E (Waters), columns were used with a flow rate of 1 mL / min. Detector: Infrared detector (2800-3000 cm-1) to collect all C-H bonds and two narrow band filters tuned to the absorption region assigned to CH3 and CH2 groups. Calibration: narrow standards of polystyrene (PS) (commercially available). Calculation of molecular weight Mj of each fraction i of eluted polymer is based on the Mark-Houwink relation (log (MpE) = 0.965909 x log10(Mps) - 0.28264) (cut off on the low molecular weight end at MPE = 1000).

[0273] The molecular weight averages used in establishing molecular weight / property relationships are the number average (Mn), weight average (Mw) and z average (Mz) molecular weight. These averages are defined by the following expressions and are determined form the calculated Mi:

[0274] Here Nj and Wj are the number and weight, respectively, of molecules having molecular weight Mj. The third representation in each case (farthest right) defines how one obtains these averages from SEC chromatograms, hi is the height (from baseline) of the SEC curve at the ithelution fraction and Mj is the molecular weight of species eluting at this increment.

[0275] • Differential Scanning Calorimetry (DSC) for Determination of Melting Temperatures

[0276] Melting temperature (Tm) was determined via Differential Scanning Calorimetry (DSC) according to ISO 11357-3:2018 on a DSC Q2000 instrument by TA Instruments, calibrated with indium and using T zero mode. To erase any prior thermal and crystallization history the samples were first heated to 220 °C at a heating rate of 10°C / min and kept at 220 °C for 5 minutes. The polymer was then cooled with a constant cooling rate of -10 °C / min up to 0 °C and kept isothermal at 0 °C for 5 minutes. The polymer was then heated to 220 °C at a constant heating rate of 10 °C / min. and the melting temperature was determined during this heating step. The melting temperature corresponds to the temperature of the extremum of the spectrogram presenting the heat flux associated with the polymer as a function of the temperature during its melting. In some cases, the thermogram can present two melting peaks. The extremum associated to the lowest temperature is labelled as Tmiand the extremum associated to the highest temperature is labelled as Tm2.

[0277] • Comonomer Content

[0278] The 1 -hexene content (wt.% Ce-) relative to the total weight of the ethylene copolymer was determined from a13C{1H} Nuclear Magnetic Resonance (NMR) spectrum.

[0279] The sample was prepared by dissolving a sufficient amount of polymer in 1 ,2,4- trichlorobenzene (TCB 99% spectroscopic grade) at 130 °C and occasional agitation to homogenize the sample, followed by the addition of hexadeuterobenzene (CeDe, spectroscopic grade) and a minor amount of hexamethyldisiloxane (HMDS, 99.5+%), with HMDS serving as internal standard. To give an example, about 220 mg of polymer were dissolved in 2.0 mL of TCB, followed by addition of 0.5 mL of CeDe and 2 to 3 drops of HMDS.13C{1H} NMR signal was recorded on a Bruker 500 MHz with a 10 mm probe (or 10mm cryoprobe) with the following conditions:

[0280] Pulse angle: 90°

[0281] Pulse repetition time: 30 s Spectral width: 25000 Hz centered at 95 ppm

[0282] Data points: 64 K

[0283] Temperature: 130 °C +1-2 °C

[0284] Rotation: 15 Hz

[0285] Scan numbers: 2000 - 4000 (240 scans with 10 mm cryoprobe) Decoupling sequence: inverse-gated decoupling sequence to avoid NOE effect

[0286] 13C{1H} NMR spectrum was obtained by Fourier Transform on 131 K points after a light Gaussian multiplication. Spectrum was phased, baseline corrected, and chemical shift scale was referenced to the internal standard HMDS at 2.03 ppm.

[0287] Chemical shifts of signals were peak picked, and peaks were integrated as mentioned on Figure 1 and in the following Table A.

[0288] Table A: integration regions of13C{1H} NMR spectrum

[0289] Small adjustments on integration limits can be applied if necessary.

[0290] Chemical shifts are given at ± 0.05 ppm.

[0291] The wt.% C6- contents are obtained by the following areas (A) combinations:

[0292] AC3 = 0.5 X AcH2(a) B1

[0293] AC4 = ACH3 B2

[0294] AC6 = ACH2(2) B4

[0295] AC2 = 0.5 X (ATV1 + ATV2 + ATV3 + Avinylidenel + Avinylidene2 + 0.5 X AcH2(a) B1 + ATS3 + 2X ATS2 + AcH2n '

[0296] AC6+AcH2(b) ) wt.% C6- = (84 * AC6) / (28 * AC2 + 42 * AC3+ 56 * AC4+ 84 * AC6) x 100.

[0297] EXAMPLES

[0298] The embodiments described herein may be further illustrated by the following non-limiting examples.

[0299] Example 1: Synthesis of particles comprising ZnO

[0300] Example 1 illustrates the synthesis of particles comprising zinc oxide (ZnO). The present example illustrates three experiments wherein ZnO particles were prepared.

[0301] In a first experiment, 658.5 mg (3.0 mmol) of zinc acetate dihydrate [Zn(Ac)2'2H2O], and 64.2 mg (0.3 mmol) of monobasic sodium citrate (NaCeHyO?) was dissolved in 75 mL of deionized water in a 100 mL Teflon liner. Subsequently, 360.4 mg (6.0 mmol) of urea [CO(NH2)2] was added to the mixture and stirred for 30 minutes to initiate the formation of a zinc-containing precipitate. The Teflon liner was transferred to a stainless-steel autoclave and the reaction was continued at 120 °C for 6 hours. The formed precipitate containing zinc was centrifuged at 3500 rpm for 5 minutes to separate the precipitated particles from the liquid mixture. After decanting, the separated particles were washed four times with 20 mL deionized water and 20 mL ethanol. The washed particles were dried in a convection oven at 80 °C for 12 hours to remove residual solvent. Then, the dried particles were calcined at 300 °C with a 2 °C min-1heating rate for 2 hours to obtain 500 mg of particles comprising ZnO.

[0302] In a second experiment, 892.5 mg (3.0 mmol) of zinc nitrate hexahydrate [Zn(NO3)2'6H2O], and 2.1 g (7.2 mmol) of trisodium citrate (NaCeHyOy) were dissolved in 60 mL of deionized water in a 100 mL container. Subsequently, 599.955 mg (15.0 mmol) of sodium hydroxide [NaOH] pellets were added to the mixture and stirred for 2 hours at 300 rpm to form a zinc-containing precipitate. The formed catalyst support was centrifuged at 3500 rpm for 5 minutes to separate the precipitated particles from the liquid mixture. After decanting, the separated particles were washed four times with 20 mL deionized water and 20 mL ethanol. The washed particles were dried in a convection oven at 60 °C for 18 hours to remove residual solvent. The dried particles comprising ZnO were obtained as a white powder.

[0303] In a third experiment, 272.6 mg (2.0 mmol) of zinc chloride (ZnCh) was dissolved in 45 mL of deionized water in a 100 mL Teflon liner. Subsequently, 280.4 mg (2.0 mmol) of hexamethylenetetramine (C6H12N4) was added to the mixture to initiate the formation of a zinc- containing precipitate. Then, 58.8 mg (0.2 mmol) of trisodium citrate dihydrate (NasCeHsOy^hLO) dissolved in 15 mL of deionized water was added to the Teflon liner. The Teflon liner was transferred to a stainless-steel autoclave and the reaction was continued at 90 °C for 3 hours. The liquid mixture was centrifuged at 3500 rpm for 5 minutes to separate precipitated particles from the liquid mixture. After decanting, the separated particles were washed four times with 20 mL deionized water and 20 mL ethanol. The washed particles were dried in a convection oven at 60 °C for 18 hours to remove residual solvent. Dried particles comprising ZnO were obtained as a white powder.

[0304] An overview of the experiments 1-3 and the resulting analyses of the obtained ZnO particles is provided in Table 1.

[0305] Table 1 above) and based on average of 5 images.

[0306] Figure 1 is a FIB-SEM image representing an example of a ZnO particle as obtained in experiment 1 as described herein above. Figure 2 is a graph showing the average pore volume as a function of average pore diameter following N2-physisorption analysis of particles obtained in experiment 1 as described herein above. Analysis of the physisorption data revealed an average pore size ranging between 20 and 70 nm.

[0307] Figure 3 is a FIB-SEM image representing an example of a particle obtained in experiment 2 as described herein above. The displayed particle has a flower-like morphology (i.e. , spherical particles comprising thin nanosheets). Figure 4 is a graph showing the average pore volume as a function of average pore diameter following N2-physisorption analysis of the particles obtained in experiment 2 as described herein above. Analysis of the physisorption data revealed that the particles contain mostly pores having an average pore diameter of about 15 nm and a few bigger pores with a diameter ranging between 30 and 90 nm.

[0308] Figure 5 is a FIB-SEM image representing an example of a particle obtained in experiment 3 as described herein above. Figure 6 is a graph showing the average pore volume as a function of average pore diameter following N2-physisorption analysis of particles as obtained in experiment 3 as described herein above. Analysis of the physisorption data revealed a uniform average pore size of about 4 nm.

[0309] The particles obtained in experiments 1-3 were further analysed using XRD to measure the nature of the crystalline domains present in said particles. The obtained particles show a hexagonal wurtzite crystal structure. Figure 7 is an XRD pattern of particles obtained with experiment 2 as described herein above.

[0310] Example 2: Synthesis of particles comprising ZnO using spray drying

[0311] The following example illustrates an embodiment of a method according to the invention for preparing particles comprising ZnO using spray-drying.

[0312] In a first experiment, a zinc-containing precipitate was formed by preparing a solution comprising a zinc salt and a precipitating agent. More specifically, zinc nitrate hexahydrate [Zn(NO3)2'6H2O] was dissolved in 250 mL deionized water and subsequently sodium hydroxide [NaOH] pellets were added in a molar ratio of zinc nitrate hexahydrate:NaOH of 1 :5 to form a mixture. The mixture was stirred for 2 hours at 300 rpm to form 50.0 g / L of zinc-containing precipitate, i.e., 12.5 g of ZnO in 250 mL deionized water. Then, the solution was processed into particles comprising ZnO by spray drying with a BUCHI B-290 acid-resistant mini spray dryer as defined in the methodology section. The solution was pumped into the spray dryer with a feeding rate of 6.0 mL / min.

[0313] Spray drying parameters were as follows: heated gas was pumped into the drying chamber at a temperature of 180 °C; the solution was provided to the drying chamber at a flow rate of 473 L / h;

[0314] - Aspirator of 100%.

[0315] An outlet temperature of 63 °C to 73 °C was measured during spray drying. The resulting powder was collected in a collection vessel.

[0316] In a second experiment, the procedure of the first experiment was repeated but with the addition of 5.6 g (15.0 mmol) of nucleating agent cetrimonium bromide (CTAB) to the solution.

[0317] Both experiments show that particles comprising ZnO according to the invention can be efficiently prepared using a method based on spray-drying.

[0318] An overview of properties of the ZnO particles obtained by spray-drying according to the above experiments is provided in Table 2.

[0319] Table 2

[0320] (*) D10, D50, and D90 values estimated by FIB-SEM analysis (see material section above) and based on average of 5 images.

[0321] Example 3: Preparation of a zinc-containing catalyst support according to the invention

[0322] The present example illustrates the preparation of a zinc-containing catalyst support comprising zinc oxide particles and an activator. In the present example, the activator was methylaluminoxane (MAO). It is further illustrated that the activator can be used at different loading concentrations.

[0323] In a first experiment (IE1), 1 g of the particles comprising ZnO of experiment 2 of Example 1 described above was added to 10 mL of 99.8% dry toluene in a flask positioned in a glovebox under nitrogen atmosphere. The obtained slurry was allowed to stir (magnetically) at 110 rpm and a temperature of 125 °C for 4 hours. Then, 0.31 mL of a 16 wt% MAO solution (obtained from W.R. Grace & Co) was added to the slurry mixture to obtain a weight loading of 30 wt%. The weight percentage of MAO in the catalyst support was determined with ICP-AES (see methodology section). After stirring for 4 hours at 110 rpm and 125 °C, the suspension was filtrated, and the residue was washed 3 times with 10 mL toluene and 10 mL pentane.

[0324] In a second experiment (IE2), 1 g of the particles comprising ZnO of experiment 2 of Example 1 described above was added to 10 mL of 99.8% dry toluene in a flask positioned in a glovebox under nitrogen atmosphere. The slurry was allowed to stir (magnetically) at 110 rpm and a temperature of 125 °C for 4 hours. Then, 1.0 mL of the 16 wt% MAO solution (obtained from W.R. Grace & Co) was added to the slurry mixture to obtain a weight loading of 48 wt%. The weight percentage of MAO in the catalyst support was determined with ICP-AES (see methodology section). After stirring for 4 hours at 110 rpm and 125 °C, the suspension was filtrated, and the residue was washed 3 times with 10 mL toluene and 10 mL pentane.

[0325] In a third experiment (IE3), 1 g of particles comprising ZnO of experiment 2 of Example 1 described above was added to 10 mL of 99.8% dry toluene in a flask positioned in a glovebox under nitrogen atmosphere. The slurry was allowed to stir (magnetically) at 110 rpm and a temperature of 125 °C for 4 hours. Then, 1.9 mL of the 16 wt% MAO solution (obtained from W.R. Grace & Co) was added to the slurry mixture to obtain a weight loading of 71 wt%. The weight percentage of MAO in the activated catalyst support was determined with ICP-AES (see methodology section). After stirring for 4 hours at 110 rpm and 125 °C, the suspension was filtrated, and the residue was washed 3 times with 10 mL toluene and 10 mL pentane.

[0326] The acidic properties of the catalyst supports of IE1-IE3 were assessed by using pyridine as probe molecule in FT-IR spectroscopy. Since the pyridine probe molecule is basic, this compound can react with the Lewis Acid Sites (LAS) on the samples. In particular, the peak around 1617 cm-1can distinguish between the Lewis acidity of Al3+with an octahedral (1614 cm-1) and tetrahedral coordination (1622 cm-1). Octahedral Al3+is a weaker Lewis acid site than tetrahedral Al3+. This peak is perturbed among different MAO loadings. Especially at lower MAO loading (see IE1 : 30 wt% MAO, and IE2: 48 wt% MAO), more octahedral Al3+than tetrahedral Al3+is present, suggesting an increase of weaker LAS. A maximum LAS concentration was observed for a MAO weight loading of 30 wt%.

[0327] For comparison, a sample of untreated ZnO particles, i.e. , with weight loading of 0 wt% MAO, obtained with experiment 2 of Example 1 , was also analyzed for LAS concentration. LAS concentration of such particles amounted to about 25.0 pmol / g.

[0328] An overview of the experiments IE1 to IE3 and the resulting properties of the particles is provided in Table 3. Table 3

[0329] Figures 8, 9 and 10 show a FIB-SEM image representing an example of the catalyst support of IE1 (30 wt% MAO loading), of IE2 (48 wt% MAO loading), and of IE3 (71wt% loading) respectively. Analysis of the displayed particles revealed that in all examples MAO has been deposited in the slit-like pores of the catalyst support.

[0330] Figure 10 further shows that the porous morphology of the support was altered, as the entire surface of the particle is substantially covered with MAO.

[0331] No substantial changes in average particle size and standard deviation of the MAO-loaded particles with respect to the pristine particles could be determined.

[0332] Furthermore, N2-physisorption experiments were conducted to determine the influence of MAO loading on the porous properties, such as surface area and pore size distribution. Figure 11 is a graph showing the average pore volume and average pore diameter following N2- physisorption analysis of the particles as obtained in IE1 , IE2 and IE3 , and a non-loaded zinc oxide particle (ZnO-0%). From this data it is clear that with MAO loading, average pore volume decreases. Moreover, the average pore diameter also decreases with MAO loading as the pores are filled with MAO material.

[0333] Example 4: Preparation of a catalyst composition according to the invention

[0334] The present example illustrates the preparation of an embodiment of a catalyst composition according to the present invention.

[0335] A catalyst suspension was prepared by adding 1.5 mg (5.96 pmol) of bis(cyclopentadienyl)dimethyl zirconium(IV) (CAS 12636-72-5, Commercially available from Sigma Aldrich (97% purity)) in 10 mL of 99.8% dry toluene in a flask positioned in a glovebox under nitrogen atmosphere. Subsequently, 0.492 g of the catalyst support of IE1 (see example 3 - 30 wt% MAO loading) was added to the suspension. After 2 hours of stirring at 110 rpm, the suspension was filtered and washed one time with 10 mL pentane and 10 mL toluene. The obtained catalyst composition A had an average particle size of about 5.0 pm. N2-physisorption analysis was applied on the catalyst composition A, and revealed that the average pore size was about 5 nm, the BET surface area was about 67.88 m2 / g, and the average pore volume was about 0.131 cm3 / g.

[0336] Figure 12 is a FIB-SEM cross-section image showing the catalyst composition obtained in this example. SEM-EDX analysis of the displayed cross-section revealed a homogeneous distribution of catalyst across the particle. The grey layer of platinum shown on Figure 12 surrounding the catalyst particle represents a protective layer applied on the particle to provide a good contrast when taking images of the catalyst particle.

[0337] When comparing the concentration of Lewis acid sites (LAS) before and after impregnating the catalyst support with the catalyst component, it was observed that the catalyst component (Zr) occupied about half of the available LAS, resulting in a decrease in LAS from 49.0 pmol / g (see Table 3, example 3) to 24.0 pmol / g.

[0338] Example 5: Polymerization process

[0339] Example 5 illustrates an embodiment of a polymerization process using a catalyst composition according to the invention for polymerizing ethylene.

[0340] The polymerization was conducted in a glass reactor (100 mL) filled with 15 mL of 99.9% heptane and 0.2 mL of 25% triethyl aluminum (TEA) co-catalyst solution in toluene. After feeding ethylene (1 .2 bar), 20 mg of the catalyst composition A as obtained in Example 4 was added. Polymerization was conducted for 1 hour under stirring at 500 rpm at room temperature.

[0341] The activity of the catalyst composition was about 1 .875 gPE*gCat'1*tr1*bar1during 1 hour of ethylene polymerization. This example illustrates that good catalyst activity is obtained under relatively mild conditions.

[0342] Example 6: Preparation of a catalyst composition according to the invention

[0343] The present example illustrates the preparation of another embodiment of a catalyst composition according to the present invention.

[0344] All procedural steps were carried out in a glove box under nitrogen atmosphere unless noted otherwise. A solution of methylaluminoxane (30 wt.%) (MAO) in toluene (obtained from W.R. Grace & Co) was used as the activator. In the present example, the catalyst composition was prepared in two steps using the following method:

[0345] Inventive example IE4

[0346] 1. Impregnation of MAO on particles comprising ZnO:

[0347] Ten grams of particles comprising ZnO of experiment 2 of Example 1 (see Table 1) described above were introduced into a round-bottomed flask equipped with a mechanical stirrer and a slurry was formed by adding 100 mL of toluene. MAO (21 mL) (30 wt% MAO loading) was added dropwise with a dropping funnel. The reaction mixture was stirred at 110 °C for 4 h. The reaction mixture was filtered through a glass frit (POR3) and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 x 20 mL). The powder was dried under reduced pressure overnight to obtain a zinc-containing catalyst support as a free-flowing grey powder.

[0348] 2. Preparation of Catalyst composition B: deposition of metallocene on ZnO / MAO support

[0349] Catalyst composition B was prepared as follows. 10 g of the zinc-containing catalyst support was suspended in toluene (100 mL) under nitrogen. Catalyst component ethylene- bis(tetrahydroindenyl)zirconium(IV) dichloride (CAS number: 112243-79-5, Commercially available from Koei Chemical Company) was introduced and the mixture was stirred 2 h at room temperature. The reaction mixture was filtered through a glass frit and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 times). The powder was dried under reduced pressure overnight to obtain a free-flowing grey powder. Properties of catalyst composition B are mentioned in Table 4.

[0350] Inventive example IE5

[0351] 1. Impregnation of MAO on particles comprising ZnO:

[0352] Ten grams of particles comprising ZnO of experiment 1 of Example 2 (see Table 2) described above were introduced into a round-bottomed flask equipped with a mechanical stirrer and a slurry was formed by adding 100 mL of toluene. MAO (21 mL) (30 wt% MAO loading) was added dropwise with a dropping funnel. The reaction mixture was stirred at 110 °C for 4 h. The reaction mixture was filtered through a glass frit (POR3) and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 x 20 mL). The powder was dried under reduced pressure overnight to obtain a zinc-containing catalyst support as a free-flowing grey powder.

[0353] 2. Preparation of Catalyst composition C: Deposition of metallocene on ZnO / MAO support:

[0354] Catalyst composition B was prepared as follows. 10 g of the zinc-containing catalyst support was suspended in toluene (100 mL) under nitrogen. Catalyst component ethylene- bis(tetrahydroindenyl)zirconium(IV) dichloride (CAS number: 112243-79-5, Commercially available from Koei Chemical Company) was introduced and the mixture was stirred 2 hours at room temperature. The reaction mixture was filtered through a glass frit and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 times). The powder was dried under reduced pressure overnight to obtain a free-flowing grey powder. Properties of catalyst composition C are mentioned in Table 4. Inventive example IE6

[0355] 1. Impregnation of MAO on particles comprising ZnO:

[0356] Ten grams of particles comprising ZnO of experiment 2 of Example 2 (Table 2) described above were introduced into a round-bottomed flask equipped with a mechanical stirrer and a slurry was formed by adding 100 mL of toluene. MAO (21 mL) (30 wt% MAO loading) was added dropwise with a dropping funnel. The reaction mixture was stirred at 110 °C for 4 h. The reaction mixture was filtered through a glass frit (POR3) and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 x 20 mL). The powder was dried under reduced pressure overnight to obtain a zinc-containing catalyst support as a free-flowing grey powder.

[0357] 2. Preparation of Catalyst composition D: Deposition of metallocene on ZnO / MAO support:

[0358] Catalyst composition D was prepared as follows. 10 g of the zinc-containing catalyst support was suspended in toluene (100 mL) under nitrogen. Catalyst component ethylene- bis(tetrahydroindenyl)zirconium(IV) dichloride (CAS number: 112243-79-5, Commercially available from Koei Chemical Company) was introduced and the mixture was stirred 2 hours at room temperature. The reaction mixture was filtered through a glass frit and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 times). The powder was dried under reduced pressure overnight to obtain a free-flowing grey powder. Properties of catalyst composition D are mentioned in Table 4.

[0359] Table 4: Properties of the catalyst compositions B to D

[0360] (*) Based on total weight of catalyst composition.

[0361] (**) D10, D50, and D90 values were determined based on laser light scattering analysis (see material section above)

[0362] Example 7: Preparation of a comparative catalyst composition

[0363] The present example illustrates the preparation of a comparative catalyst composition (herein “Comp. Cata”). All procedural steps were carried out in a glove box under nitrogen atmosphere unless noted otherwise. A solution of methylaluminoxane (30 wt.%) (MAO) in toluene from W.R. Grace & Co was used as the activator. The comparative catalyst composition was prepared using the following method:

[0364] 1. Impregnation of MAO on silica (SiO ) particles:

[0365] In this example, commercially available silica particles (tradename ES757 and obtained from Ecovyst Inc.) were applied. Properties of the silica particles are given in Table 5.

[0366] Table 5: Properties of silica (SiCh) particles

[0367] Ten grams of these commercially available silica particles were introduced into a round- bottomed flask equipped with a mechanical stirrer and a slurry was formed by adding 100 mL of toluene. MAO (21 mL) (30wt% MAO loading) was added dropwise with a dropping funnel. The reaction mixture was stirred at 110 °C for 4 h. The reaction mixture was filtered through a glass frit (POR3) and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 x 20 mL). The powder was dried under reduced pressure overnight to obtain a SiO2 / MAO support as a free-flowing grey powder.

[0368] 2. Preparation of a comparative catalyst composition: deposition of metallocene on S1O2 / MAO support:

[0369] The Comp. Cata was prepared as follows. 10 g of the SiO2 / MAO support was suspended in toluene (100 mL) under nitrogen. Catalyst component ethylene- bis(tetrahydroindenyl)zirconium(IV) dichloride (CAS number: 112243-79-5, Commercially available from Koei Chemical Company) was introduced and the mixture was stirred 2 hours at room temperature. The reaction mixture was filtered through a glass frit and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 times). The powder was dried under reduced pressure overnight to obtain a free-flowing grey powder. The samples were analyzed for zirconium and aluminum content (wt.%) using ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectroscopy). Properties of the comparative catalyst composition are listed in Table 6.

[0370] Table 6: Properties of the comparative catalyst composition (*) Based on total weight of catalyst composition.

[0371] (**) D10, D50, and D90 values were determined based on laser light scattering analysis (see material section above)

[0372] Example 8: Olefin polymerization process

[0373] This example illustrates an embodiment of an olefin polymerization process using a catalyst composition according to the invention for preparing ethylene (co)polymers.

[0374] Polymerization reactions were performed in a 132 mL autoclave with an agitator, a temperature controller, and inlets for feeding of ethylene and hydrogen. The reactor was dried at 110 °C with nitrogen during 1 hour and then cooled to 40 °C.

[0375] All polymerizations were performed under heterogenous conditions depicted in Table 7 (unless otherwise stated). In experiment PE1 no comonomer was added. In experiments PE2 to PE5 different concentrations of 1 -Hexene comonomer were supplied to the autoclave reactor.

[0376] Table 7

[0377] *ln ethylene feed.

[0378] In all experiments PE1 to PE5 the catalyst composition B (Table 4) was used and a same hydrogen concentration was applied. In addition, a comparative polyethylene polymer (CE1) was produced using the same polymerization conditions but in the presence of the comparative catalyst composition (Comp, cata) described herein in Example 7.

[0379] Polymerization started upon catalyst composition suspension injection, was performed at 85 °C, and was stopped after 60 minutes by reactor depressurization. The autoclave was subsequently flushed with nitrogen prior to opening. The results and variable conditions of the polymerization are shown in Table 8.

[0380] Table 8

[0381] *ln comparison to iC4.

[0382] It can be observed in Table 8 that catalyst composition B used to prepare PE1-PE5 is able to produce polymers at a similar activity / efficiency as compared to the comparative catalyst composition of Example 7, despite the lower aluminum and zirconium content of the catalyst composition.

[0383] Example 9: Olefin polymerization process

[0384] Example 9 illustrates another embodiment of a polymerization process using a catalyst composition according to the invention for preparing ethylene (co)polymers.

[0385] Polymerization reactions were performed in a 132 mL autoclave with an agitator, a temperature controller, and inlets for feeding of ethylene and hydrogen. The reactor was dried at 110 °C with nitrogen during 1 hour and then cooled to 40 °C.

[0386] All olefin polymerizations were performed under the conditions depicted in Table 9 (unless otherwise stated). In all experiments PE6 to PE10, a same amount of 1-Hexene comonomer was supplied to the autoclave reactor.

[0387] Table 9

[0388] *ln comparison to iC4.

[0389] In all experiments PE6 to PE10, catalyst composition B was used. In addition, a comparative polyethylene polymer (CE2) was produced using the same polymerization conditions but in the presence of the comparative catalyst composition (Comp, cata) described herein in Example 7.

[0390] Polymerization started upon catalyst composition suspension injection, was performed at 85 °C, and was stopped after 60 minutes by reactor depressurization. The autoclave was subsequently flushed with nitrogen prior to opening. The results and variable conditions of the polymerization are shown in Table 10.

[0391] Table 10

[0392] *ln ethylene feed.

[0393] Example 10: Olefin polymerization process

[0394] Example 10 illustrates another embodiment of an olefin polymerization process using a catalyst composition according to the invention for preparing ethylene-hexene copolymers.

[0395] Polymerization reactions were performed in a 132 mL autoclave with an agitator, a temperature controller, and inlets for feeding of ethylene and hydrogen. The reactor was dried at 110 °C with nitrogen during and then cooled to 40 °C.

[0396] All polymerizations were performed under heterogenous conditions depicted in Table 11 (unless otherwise stated). In all experiments PE11 to PE12, a same amount of 1-hexene comonomer and hydrogen was supplied to the autoclave reactor.

[0397] Table 11

[0398] *ln comparison to iC4, **ln ethylene feed. In experiment PE11 the catalyst composition C was used. In experiment PE12 the catalyst composition D was used. In addition, a comparative polyethylene polymer (CE3) was produced using the same polymerization conditions but in the presence of the comparative catalyst composition (Comp, cata) described herein in Example 7. Polymerization started upon catalyst composition suspension injection, was performed at 85 °C, and was stopped after 60 minutes by reactor depressurization. The autoclave was subsequently flushed with nitrogen prior to opening. The results and variable conditions of the polymerization are shown in Table 12.

[0399] It can be observed in Table 12 that catalyst compositions according to the invention (catalyst compositions C and D), may be used to prepare polymers (PE11-PE12) at higher catalyst activity than the comparative composition. The difference in catalyst activity can be advantageously attributed to the properties of the zinc-containing catalyst support used to load the MAO material and the metallocene catalyst component.

[0400] Table 12

[0401] *ln ethylene feed.

[0402] The obtained polymers PE11 and PE12 were analyzed by means of ICP-AES as described herein in the methodology section to determine the residual amount of zirconium (Zr) and zinc (Zn) in the polymer. The results of said measurement are summarized in Table 13.

[0403] Table 13

[0404] Example 11 : Preparation of a zinc-containing catalyst support and a comparative support

[0405] This example illustrates the preparation of two catalyst supports according to the invention and a comparative catalyst support.

[0406] ZnO particles The supports were prepared starting from ZnO material obtained from Nanostructured & Amorphous material Inc (Nanoamor) (US).

[0407] In a first experiment (Experiment A), 120 g of the ZnO as obtained from Nanoamor (US), was suspended in 606 mL deionized water, and was stirred for 2 hours at 300 rpm to form 200.0 g / L of zinc-containing precipitate. Then, the solution was processed into particles comprising ZnO by spray drying with a BUCHI B-290 acid-resistant mini spray dryer as defined in the methodology section. Spray drying parameters were as follows:

[0408] The solution was pumped into the spray dryer with a feeding rate of 10.5 mL / min (i.e. , 0.63 L / h).

[0409] Heated gas (air) was pumped into the drying chamber at a temperature of 220°C.

[0410] The heated gas was provided to the drying chamber at a flow rate of 246 L / h;

[0411] - Aspirator of 100%; pressure was 0.7 MPa.

[0412] An outlet temperature of about 106 °C was measured during spray drying. The resulting powder was collected in a collection vessel.

[0413] In a second experiment (Experiment B), the ZnO as obtained from Nanoamor (US) was used as such.

[0414] An overview of properties of ZnO particles prepared or used in respectively experiments A and B is provided in Table 14. Parametric properties were determined as explained in the methodology section. The average particle size of the ZnO particles in experiments A and B is in the range of 2 to 100 pm.

[0415] Table 14

[0416] Preparation of ZnO containing catalyst supports:

[0417] The ZnO particles as disclosed in Experiments A and B above were used to prepare zinc- containing catalyst supports. All procedural steps were carried out in a glove box under nitrogen atmosphere unless noted otherwise. A solution of methylaluminoxane (30 wt.%) (MAO) in toluene was used as the activator. To that end, in one experiment (support A), ten grams of particles comprising ZnO of experiment A of Example 11 (see Table 14) described above were introduced into a round- bottomed flask equipped with a mechanical stirrer and a slurry was formed by adding 100 mL of toluene. MAO (21 mL) (30 wt% MAO loading) was added dropwise with a dropping funnel. The reaction mixture was stirred at 110 °C for 4 h. The reaction mixture was filtered through a glass frit (POR3) and the powder was washed with dry toluene (3 x20 mL) and with dry pentane (3 x 20 mL). The powder was dried under reduced pressure overnight to obtain a zinc- containing catalyst support.

[0418] In another experiment (support B), ten grams of particles comprising ZnO of experiment B of Example 11 (see Table 14) described above were introduced into a round-bottomed flask equipped with a mechanical stirrer and a slurry was formed by adding 100 mL of toluene. MAO (21 mL) (30 wt% MAO loading) was added dropwise with a dropping funnel. The reaction mixture was stirred at 110 °C for 4 h. The reaction mixture was filtered through a glass frit (POR3) and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 x 20 mL). The powder was dried under reduced pressure overnight to obtain a zinc-containing catalyst support.

[0419] For comparison, commercially available silica particles (tradename ES757, see Table 5) were used to prepare a comparative catalyst support. To that end the silica (SiO2) particles were impregnated with MAO as follows.

[0420] Ten grams of these commercially available silica particles were introduced into a round- bottomed flask equipped with a mechanical stirrer and a slurry was formed by adding 100 mL of toluene. MAO (21 mL) (30wt% MAO loading) was added dropwise with a dropping funnel. The reaction mixture was stirred at 110 °C for 4 h. The reaction mixture was filtered through a glass frit (POR3) and the powder was washed with dry toluene (3 x20 mL) and with dry pentane (3 x 20 mL). The powder was dried under reduced pressure overnight to obtain a SiO2 / MAO support as a free-flowing grey powder.

[0421] Example 12: Preparation of catalyst compositions

[0422] This example illustrates the preparation of two catalyst compositions according to the invention (Composition E and F) and a comparative catalyst composition.

[0423] Inventive catalyst composition IE7

[0424] Catalyst composition E was prepared as follows. 10.1 g of the zinc-containing catalyst support (Support A - example 11) was suspended in toluene (100 mL) under nitrogen. 0.192 g Catalyst component ethylene-bis(tetrahydroindenyl)zirconium(IV) dichloride (CAS number: 112243- 79-5, Commercially available from Koei Chemical Company) was introduced and the mixture was stirred 2 h at room temperature. The reaction mixture was filtered through a glass frit and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 times). The powder was dried under reduced pressure overnight to obtain a free-flowing grey powder.

[0425] Inventive catalyst composition IE8

[0426] Catalyst composition F was prepared as follows. 10.21 g of the zinc-containing catalyst support (Support B - example 11) was suspended in toluene (100 mL) under nitrogen. 0.192 g Catalyst component ethylene-bis(tetrahydroindenyl)zirconium(IV) dichloride (CAS number: 112243-79-5, Commercially available from Koei Chemical Company) was introduced and the mixture was stirred 2 h at room temperature. The reaction mixture was filtered through a glass frit and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 times). The powder was dried under reduced pressure overnight to obtain a free-flowing grey powder.

[0427] Comparative catalyst composition

[0428] A comparative composition was prepared as follows. 9.95 g of the SiCh / MAO support (see comparative support - example 11) was suspended in toluene (100 mL) under nitrogen. 0.195 g Catalyst component ethylene-bis(tetrahydroindenyl)zirconium(IV) dichloride (CAS number: 112243-79-5, Commercially available from Koei Chemical Company) was introduced and the mixture was stirred 2 hours at room temperature. The reaction mixture was filtered through a glass frit and the powder was washed with dry toluene (3 x 20 mL) and with dry pentane (3 times).

[0429] The powder was dried under reduced pressure overnight to obtain a free-flowing powder. The samples of catalyst compositions E, F and the comparative composition were analyzed for zinc, zirconium and aluminum content (wt.%) using ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectroscopy). Results of ICP analyses performed on the catalyst compositions E and F and of the comparative catalyst compositions are listed in Table 15.

[0430] Table 15 Example 13: Olefin polymerization process

[0431] Example 13 illustrates olefin polymerization processes using the catalyst compositions reported in example 12 for preparing ethylene-hexene copolymers. All polymerizations were performed in an 4 liter autoclave reactor under heterogenous conditions depicted in Table 16. In all experiments, a same amount of 1 -hexene comonomer and hydrogen was supplied to the autoclave reactor.

[0432] Table 16

[0433] *ln comparison to iC4, **ln ethylene feed.

[0434] In experiment PE15 the catalyst composition E was used. In experiment PE16 the catalyst composition F was used. In addition, a comparative polyethylene polymer (CE5) was produced using the same polymerization conditions but in the presence of the comparative catalyst composition described herein in Example 12. The polymerization reactions were performed with isobutane as diluent. In all experiments, a same amount of 1-hexene comonomer and hydrogen was supplied to the reactor. Polymerization started upon catalyst composition suspension injection, was performed at 85 °C, and was stopped after 60 minutes by reactor depressurization. Results on efficiency and productivity of the polymerization are shown in Table 17.

[0435] Table 17

[0436] It can be observed in Table 17 that catalyst compositions according to the invention (catalyst compositions E and F), may be used to prepare polymers (PE15-PE16) at higher catalyst activity, hence at better productivity, than when the comparative catalyst composition is used.

Claims

67CLAIMS1. A zinc-containing catalyst support for an olefin polymerisation catalyst, preferably for a metallocene-based olefin polymerisation catalyst, wherein the support comprises particles comprising at least 80.0 wt% of zinc oxide (ZnO) with wt% based on the total weight of the particles; and wherein the particles have an average particle size of between at least 2.0 and at most 100.0 pm, and an activator, preferably wherein the activator is an organoaluminum compound.

2. The catalyst support according to claim 1 , wherein the catalyst support has a BET surface area of between at least 20.00 and at most 750.00 m2 / g.

3. The catalyst support according to any one of the preceding claims, wherein the catalyst support has a concentration of Lewis acid sites (LAS) of at least 15.0 pmol / g to at most 100.0 pmol / g.

4. The catalyst support according to any one of the preceding claims, wherein the particles comprising ZnO comprise at least 90.0 wt% of ZnO, with wt% based on the total weight of the particles.

5. The catalyst support according to any one of the preceding claims, wherein the amount of activator is comprised between 20.0 wt% and 75.0 wt%, such as between 25.0 and 45.0 wt%, with wt% based on the total weight of the catalyst support.

6. The catalyst support according to any one of the preceding claims, wherein the catalyst support comprises at least 50.0 wt% of said particles comprising ZnO, with wt% based on the total weight of the catalyst support.

7. The catalyst support according to any one of the preceding claims, wherein the organoaluminum compound is an aluminoxane compound of formula (A1) or (A2)Ra-(AI(Ra)-O)x-AIRa2 (A1) for oligomeric, linear aluminoxanes; or(-AI(Ra)-O-)y(A2) for oligomeric, cyclic aluminoxanes; wherein x is an integer between 1 and 40, and preferably between 10 and 20; wherein y is an integer between 3 and 40, and preferably between 3 and 20; and wherein each Rais independently selected from a Ci-salkyl , and preferably is a Ci- 4alkyl, more preferably is methyl or ethyl.

688. A method for the preparation of a zinc-containing catalyst support, preferably a zinc- containing catalyst support according to any one of the preceding claims, comprising the steps of: a) forming a zinc-containing precipitate by preparing a solution comprising a zinc salt, a precipitating agent, and optionally a nucleating agent; b) processing said solution into particles comprising zinc oxide (ZnO); and c) treating said particles comprising ZnO with an activator, preferably wherein the activator is an organoaluminum compound, thereby obtaining a zinc-containing- catalyst support.

9. The method according to claim 8, wherein the zinc salt comprises a water-soluble zinc salt, and preferably is selected from the group consisting of zinc nitrate, zinc chloride, zinc acetate, zinc bromide, zinc iodide, zinc carbonate, zinc sulphate, zinc 2- ethylhexanoate, zinc gluconate, zinc citrate, any hydrates thereof, and any mixtures thereof.

10. The method according to claim 8 or 9, wherein the precipitating agent comprises a water-soluble basic salt, and preferably is selected from the group consisting of hexamethylenetetramine, NaOH, urea, KOH, NH4OH, NaHCCh, (NH^COa, and any mixtures thereof.

11. The method according to any one of claims 8 to 10, wherein the nucleating agent comprises a tricarboxylic acid compound, preferably selected from the group consisting of citric acid, citrate salt, isocitric acid, isocitrate salt, aconitic acid, aconitate salt, tricarballylic acid, tricarballylate salt, trimesic acid, trimesate salt, trimellitic acid, trimellitate salt, and mixtures thereof, and / or a surfactant, preferably a cationic surfactant, more preferably an alkylammonium salt of the Formula (NR2xH4-x)Y, wherein R2is a Ci-2oalkyl, x is an integer ranging from 1-4, and Y is a fluoride, chloride, bromide, or iodide.

12. The method according to any one of claims 8 to 11 , wherein step b) comprises subjecting the solution of step a) to spray drying, drying, flash drying, or any combinations thereof.

13. A catalyst composition for olefin polymerization comprising:a zinc-containing catalyst support according to any one of claims 1 to 7, or obtained or obtainable by carrying out a method according to any one of claims 8 to 12; a catalyst component, such as a metallocene catalyst; and - optionally a co-catalyst, preferably selected from the group consisting of an organoaluminium compound, an organoboron or organoborate compound, an ionizing ionic compound, or any combinations thereof.

14. Use of particles comprising zinc oxide (ZnO), as defined in any one of claims 1 to 7, for preparing a catalyst support, preferably for preparing a support for an olefin polymerization catalyst, more preferably for preparing a support for a metallocene- based olefin polymerization catalyst.

15. Use of a catalyst composition according to claim 13, in a polymerization process for preparing an olefin polymer.

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