Self-extinguishing catalyst system for propylene polymerization

Abstract

The present invention relates to a catalyst system for polymerization of polyolefins preferably polypropylene based polymer comprising one or more Ziegler-Natta procatalyst compositions; one or more internal donors; one or more cocatalysts, preferably an aluminum containing cocatalyst; one or more external donors comprising a mixture of: one or more selectivity control agents (SCA); one or more activity limiting agents (ALA); wherein the activity limiting agent (ALA) is a compound according to formula (I), wherein R1 and R2 are independently selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxycarbonyl, alkylaryl having 1 to 15 carbon atoms; wherein R3 is selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxycarbonyl or alkylaryl having 1 to 10 carbon atoms or R3 is represented by -O-R4- O- or -O-R4- wherein R4 is selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxycarbonyl, alkylaryl having 1 to 10 carbon atoms.

Description

[0001] SELF-EXTINGUISHING CATALYST SYSTEM FOR PROPYLENE POLYMERIZATION

[0002] BACKGROUND:

[0003] The present invention relates to a catalyst system for polymerization of polyolefins preferably polypropylene base polymer comprising one or more Ziegler-Natta type procatalyst compositions, one or more internal donors, one or more co-catalysts, one or more external donors comprising a mixture of one or more selectivity control agents (SCA) and one or more activity limiting agents (ALA).

[0004] Ziegler-Natta catalyst systems and their components are generally known. The term “Ziegler- Natta” is known in the art and it typically refers to catalyst systems comprising a transition metalcontaining solid catalyst compound (also typically referred to as a procatalyst); an organometallic compound (also typically referred to as a co-catalyst) and optionally one or more electron donor compounds (e.g. external electron donors).

[0005] The transition metal-containing solid catalyst compound comprises a transition metal halide supported on a metal or metalloid compound. An overview of such catalyst types is for example given by T. Pullukat and R. Hoff in Catal. Rev. — Sci. Eng. 41, vol. 3 and 4, 389-438, 1999. The preparation of such a procatalyst is for example disclosed in WO96 / 32427 AL

[0006] Catalyst compositions designed primarily for the polymerization of propylene or mixtures of propylene and ethylene generally include a selectivity control agents (SCA) in order to affect polymer properties, especially tacticity or stereoregularity of the polymer backbone. As one indication of the level of tacticity, especially the isotacticity of polypropylene, the quantity of such polymer that is soluble in xylene, trichlorobenzene (TCB), or similar liquid that is a non-solvent for the tactic polymer is often used. In addition to tacticity control, molecular weight distribution (MWD), melt flow (MF), and other properties of the resulting polymer are affected by use of a selectivity control agent (SCA) as well. It has also been observed that the activity of the catalyst composition as a function of temperature may be affected by the choice of the selectivity control agent (SCA). Often however, a selectivity control agent (SCA) which gives desirable control over one polymer property is ineffective or detrimental with respect to additional properties or features. Conversely, a selectivity control agent (SCA) that is effective in combination with one procatalyst may not be effective when used in combination with a different procatalyst. Such catalyst system when operated at high temperature results into reactor fouling or sheeting.

[0007] With regard to the temperature dependence of catalyst activity, it is known that the use of certain alkoxy derivatives of aromatic carboxylic acid esters in combination with a Ziegler-Natta procatalyst composition containing an ester of an aromatic monocarboxylic acid, exemplified by ethyl benzoate, results in an inherently self-extinguishing catalyst system with respect to temperature. Such catalyst systems are less active at moderately elevated polymerization temperatures, especially temperatures from about 100° to 130° C. Using such systems, less reactor fouling or sheeting is observed, and issues related to run-away of reactors due to increased polymerization rates at elevated temperatures, are largely eliminated. Disadvantageously, the use of such catalyst systems some ZN catalyst system results in poor polymerization activity and production of polypropylene polymers having low isotacticity.

[0008] Therefore, there remains a need to provide a Ziegler-Natta catalyst system for the polymerization of olefins, wherein the catalyst system provides the advantages of an SCA containing catalyst system retaining the polymer properties in particular low soluble fraction but additionally possesses improved temperature / activity properties. Especially desired are such compositions that are inherently self-extinguishing with regard to catalyst activity as a function of temperature, thereby leading to reduced polymer agglomerate formation and improved polymerization process control without imparting an undesired odor to the polymer.

[0009] Hence, to overcome the above-cited problems, it is thus an object of the invention to provide an improved self-extingui shing catalyst system for the polymerization of olefins that reduces the catalyst activity at the threshold temperature i.e. 80 - 130 °C leading to the reduction in polymer agglomerate formation and improved polymerization process control without imparting an undesired odor to the polymer.

[0010] WO20 19 / 144976 A2 discloses an alpha-olefin polymerisation Z-N catalyst comprising (A) a solid catalyst component, (B) a cocatalyst organoaluminium compound and (C) a dual-function external electron donor compound. The catalyst component comprises magnesium chloride as a carrier, a transition metal such as titanium and a composite aromatic diacid diester / l,3-diether as an internal electron donor. One or more organoaluminiums act as a cocatalyst. The dual-function external electron donor is a composite of a composite external electron donor hydrocarbyl meth(eth)oxy silicon and a polymerisation temperature control agent organic acid ester.

[0011] CN105315390A discloses a catalyst composition for olefin polymerization reaction. The catalyst composition comprises a solid catalyst component a, alkyl aluminum b, and an external electron donor, i.e., a malonate compound c. The solid catalyst component a contains magnesium, titanium, halogen, and internal electron donor which contains lone pair electrons and is at least one selected from the group consisting of ethers, esters, etc.; the external electron donor c can also be a mixture of a diether compound, alkoxy silane and malonate.

[0012] WO2022 / 112389A1 discloses a process for the preparation of a solid support for a procatalyst suitable for preparing a catalyst composition for olefin polymerization with improved yield and xylene solubles.

[0013] SUMMARY

[0014] The present invention discloses a catalyst system of the present invention comprises one or more Ziegler-Natta procatalyst compositions, one or more aluminum containing cocatalysts, one or more internal donors and one of more external donors comprising a mixture of one or more selectivity control agents (SCA) and one or more activity limiting agents (ALA) wherein the activity limiting agents (ALA) is a compound according to formula (I):

[0015] Formula (I) wherein R1and R2are independently selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxycarbonyl, alkylaryl having 1 to 15 carbon atoms; wherein R3is selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 10 carbon atoms or R3 is represented by -O-R4-O- or -O-R4- wherein R4is selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 10 carbon atoms. Thus, the activity limiting agent can be a compound according to:

[0016] R'O-CO-OR4O-CO-OR2or R'O-CO-OR4-CO-OR2.

[0017] As described in the present disclosure, it will be appreciated that the one or more internal donors is used for the preparation of the one or more Ziegler-Natta procatalyst compositions.

[0018] In another aspect, the present invention relates to the polymerization of an olefin based polymer specially a polyolefin, preferably a polypropylene or a mixture of propylene or one or more propylene copolymers and alpha-olefin, obtained or obtainable by the process as described herein wherein the alpha olefin is preferably ethylene, 1 -butene, 1 -hexene and / or 1 -octene.

[0019] In yet another aspect, the invention relates to a shaped article, comprising the polyolefin as described herein.

[0020] The process of polymerization comprising the present catalyst system is conducted under such conditions of temperature and SCA / ALA content that no substantial formation of the polymer agglomerates in the polymer produced along with the reduction in the sheeting or fouling of the reactor surfaces, and most preferably, elimination of the sheeting or fouling of the reactor surfaces.

[0021] These aspects and embodiments will be described in more detail below.

[0022] DETAILED DESCRIPTION

[0023] The following definitions are used in the present description and claims to define the stated subject matter. Other terms not cited below are meant to have the generally accepted meaning in the field.

[0024] “internal donor ” or “internal electron donor” or “ID” as used in the present description means: an electron-donating compound containing one or more atoms of oxygen (O) and / or nitrogen (N). This ID is used as a reactant in the preparation of a solid procatalyst. An internal donor is commonly described in prior art for the preparation of a solid-supported Ziegler-Natta catalyst system for olefins polymerization; i.e. by contacting a magnesium-containing support with a halogen-containing Ti compound and an internal donor.

[0025] “activator” as used in the present description means: an electron-donating compound containing one or more atoms of oxygen (O) and / or nitrogen (N) which is used to during the synthesis of the procatalyst prior to or simultaneous with the addition of an internal donor. "activity limiting agent" (ALA) as used in the present description means: a material that reduces catalyst activity at elevated temperature i.e. reduces the thermal runaway of the catalysts.

[0026] “selectivity control agent” (SCA) as used in the present description means: a composition that improves the stereoregularity of a polymer. It should be understood that the definitions of ALA and SCA are not mutually exclusive and that a single compound may be categorized as both an activity limiting agent and a selectivity control agent.

[0027] “procatalysf ’ and “catalyst component” as used in the present description have the same meaning: a component of a catalyst composition generally comprising a solid support, a transition metalcontaining catalytic species and / or one or more internal donors.

[0028] “halide” or “halide ion” or “halogen” or “halogen atom” as used in the present description means: an ion selected from the group of: fluoride (F-), chloride (C1-), bromide (Br-) or iodide (I-).

[0029] “Heteroatom” as used in the present description means: an atom other than carbon or hydrogen. However, as used herein - unless specified otherwise, such as below, - when “one or more hetereoatoms” is used one or more of the following is meant: F, Cl, Br, I, N, O, P, B, S or Si. Thus a heteroatom also includes halides.

[0030] “heteroatom selected from group 13, 14, 15, 16 or 17 of the IUPAC Periodic Table of the Elements” as used in the present description means: a hetero atom selected from B, Al, Ga, In, T1 [Group 13], Si, Ge, Sn, Pb [Group 14], N, P, As, Sb, Bi [Group 15], O, S, Se, Te, Po [Group 16], F, Cl, Br, I, At [Group 17], More preferably,” heteroatom selected from group 13, 14, 15, 16 or 17 of the IUPAC Periodic Table of the Elements” includes N, O, P, B, S, or Si.

[0031] "hydrocarbyl" as used in the present description means: is a substituent containing hydrogen and carbon atoms, or linear, branched or cyclic saturated or unsaturated aliphatic radical, such as alkyl, alkenyl, alkadienyl and alkynyl; alicyclic radical, such as cycloalkyl, cycloalkadienyl cycloalkenyl; aromatic radical, such as monocyclic or polycyclic aromatic radical, as well as combinations thereof, such as alkaryl and aralkyl.

[0032] “substituted hydrocarbyl” as used in the present description means: is a hydrocarbyl group that is substituted with one or more non-hydrocarbyl substituent groups. A non-limiting example of a non-hydrocarbyl substituent is a heteroatom. Examples are alkoxycarbonyl (viz. carboxylate) groups. When in the present description “hydrocarbyl” is used it can also be “substituted hydrocarbyl”, unless stated otherwise.

[0033] “alkyl” as used in the present description means: an alkyl group being a functional group or sidechain consisting of carbon and hydrogen atoms having only single bonds. An alkyl group may be straight or branched and may be un-substituted or substituted. It may or may not contain heteroatoms, such as oxygen (O), nitrogen (N), phosphorus (P), silicon (Si) or sulphur (S).

[0034] “aryl” as used in the present description means: an aryl group being a functional group or sidechain derived from an aromatic ring. An aryl group and may be un-substituted or substituted with straight or branched hydrocarbyl groups. It may or may not contain heteroatoms, such as oxygen (O), nitrogen (N), phosphorus (P), silicon (Si) or sulphur (S). An aryl group also encloses alkaryl groups wherein one or more hydrogen atoms on the aromatic ring have been replaced by alkyl groups.

[0035] “aralkyl” as used in the present description means: an arylalkyl group being an alkyl group wherein one or more hydrogen atoms have been replaced by aryl groups

[0036] “alkoxide” or “alkoxy” as used in the present description means: a functional group or side-chain obtained from a alkyl alcohol. It consist of an alkyl bonded to a negatively charged oxygen atom.

[0037] “aryloxide” or “aryloxy” or “phenoxide” as used in the present description means: a functional group or side-chain obtained from an aryl alcohol. It consist of an aryl bonded to a negatively charged oxygen atom.

[0038] “Grignard reagent” or “Grignard compound” as used in the present description means: a compound or a mixture of compounds of formula R4zMgX42-z (R4, z, and X4are as defined below) or it may be a complex having more Mg clusters, e.g. R4Mg3Ch.

[0039] “MWD” or “Molecular weight distribution” as used in the present description means: the same as “PDI” or “polydispersity index”. It is the ratio of the weight-average molecular weight (Mw) to the number average molecular weight (Mn), viz. Mw / Mn, and is used as a measure of the broadness of molecular weight distribution of a polymer. “polymerization conditions” as used in the present description means: temperature and pressure parameters within a polymerization reactor suitable for promoting polymerization between the procatalyst and an olefin to form the desired polymer. These conditions depend on the type of polymerization used.

[0040] "production rate" or “yield” as used in the present description means: the amount of kilograms of polymer produced per gram of procatalyst consumed in the polymerization reactor per hour, unless stated otherwise.

[0041] Unless stated otherwise, when it is stated that any R group is “independently selected from” this means that when several of the same R groups are present in a molecule they may have the same meaning of they may not have the same meaning. For example, for the compound RM, wherein R is independently selected from ethyl or methyl, both R groups may be ethyl, both R groups may be methyl or one R group may be ethyl and the other R group may be methyl.

[0042] It is to be understood that the present invention is not limited to the use of any particular polymerization conditions in practice. In fact, the invention is particularly beneficial when employed under gas phase polymerization conditions, in as much as control of reaction temperature and prevention of polymer agglomeration is especially critical in a gas phase polymerization.

[0043] Unless stated to the contrary or conventional in the art, all parts and percents used herein are based on weight.

[0044] The term “mixture1when used with respect to SCA’s, means the use of two or more SC A components, simultaneously during at least a portion of a polymerization. The individual SCA's may be added separately to a reactor or premixed and added to the reactor in the form of the desired mixture. In addition, other components of the polymerization mixture, including the procatalyst, may be combined with one or more of the SCA's of the mixture, and / or the procatalyst, cocatalyst and a portion of the monomer optionally prepolymerized, prior to addition to the reactor.

[0045] If multiple reactors are employed in a polymerization wherein the present SCA / ALA mixture is utilized, it is to be understood that different individual components of the SCA and ALA may be employed in either reactor and that the present mixture need not be employed in all reactors of the multiple reactor train.

[0046] The present invention is described below in more detail. All embodiments described with respect to the present invention are also applicable to the other aspects of the invention, unless otherwise stated.

[0047] As stated above, the catalyst system of the present invention provides the desirable polymer properties such as soluble fraction content, and are largely retained while substantially controlling the polymerization activity of the catalyst composition at elevated reactor temperatures, especially reactor temperatures from 80 to 130° C, preferably from 80 to 120° C, preferably from 100 to 120° C. Such catalyst systems demonstrating substantially decreased activity at elevated temperatures, especially at temperatures greater than 100° C, more preferably greater than 80° C are said to be self-extinguishing. In addition, if a polymerization process, especially a fluidized bed, gas-phase polymerization, running at normal processing conditions is capable of interruption and resulting collapse of the bed without adverse consequences with respect to agglomeration of polymer particles, the catalyst composition is said to be self-extinguishing.

[0048] The above mentioned self-extingui shing catalyst system of the present invention comprises: a. one or more Ziegler-Natta procatalyst compositions; b. one or more internal donors; c. one or more cocatalysts, preferably an aluminum containing cocatalyst; d. one or more external donors comprising a mixture of: i. one or more selectivity control agents (SC A); ii. one or more activity limiting agents (ALA) compounds; wherein the activity limiting agent (ALA) is a compound according to formula (I)

[0049] Formula (I) wherein R1and R2are independently selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxycarbonyl, alkylaryl having 1 to 15 carbon atoms; wherein R3is selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 10 carbon atoms or R3 is represented by -O-R4-O- or -O-R4- wherein R4is selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 10 carbon atoms.

[0050] As described in the present disclosure, the one or more internal donors is used for the preparation of the comprises one or more Ziegler-Natta procatalyst compositions. The above mentioned selfextinguishing catalyst system of the present invention comprises: a. one or more Ziegler-Natta procatalyst compositions; b. one or more internal donors in the one or more Ziegler-Natta procatalyst compositions; c. one or more cocatalysts, preferably an aluminum containing cocatalyst; d. one or more external donors comprising a mixture of: i. one or more selectivity control agents (SC A); ii. one or more activity limiting agents (ALA); wherein the activity limiting agent (ALA) is a compound according to formula (I)

[0051] Formula (I) wherein R1and R2are independently selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxycarbonyl, alkylaryl having 1 to 15 carbon atoms; wherein R3is selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 10 carbon atoms or R3 is represented by -O-R4-O- or -O-R4- wherein R4is selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 10 carbon atoms.

[0052] The one or more Ziegler-Natta procatalyst compositions may be prepared by contacting a magnesium-containing support with a halogen-containing titanium compound and the internal donor. The catalyst system of the present invention may be prepared by contacting said Ziegler- Natta procatalyst compositions with the aluminum containing cocatalyst and the selectivity control agent (SCA) in combination with the activity limiting agent (ALA).

[0053] In an embodiment of the present invention, wherein the activity limiting agent (ALA) is a compound according to formula (I)

[0054] Formula (I) wherein R1and R2having preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, more preferably 1-8 carbon atoms; wherein R3having preferably 1 to 8 carbon atoms, more preferably 1-6 carbon atoms.

[0055] Preferably, R1and R2are independently selected from a group of linear or branched chains of unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 15 carbon atoms and wherein R3 is represented by -O-R4-O- or -O-R4- wherein R4is selected from a group of linear or branched chains of unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 10 carbon atoms.

[0056] Suitable activity limiting agents (ALA) according to formula (I) comprises 2,4- bis[(ethoxycarbonyl)oxy]pentane, 2,4-bi s( { [(2-methylpropoxy)carbonyl]oxy ((pentane, 2,4- bis[(butoxycarbonyl)oxy]pentane, {[({4-[(phenoxycarbonyl)oxy]pentan-2- yl(oxy)carbonyl]oxy (benzene, {[({7-[(ethoxycarbonyl)oxy]heptyl(oxy)carbonyl]oxy(ethane, 2- methyl-l-({[(7-{[(2-methylpropoxy)carbonyl]oxy(heptyl)oxy]carbonyl}oxy)propane, l-{[({7- [(butoxycarbonyl)oxy]heptyl(oxy)carbonyl]oxy (butane, 7-[(phenoxycarbonyl)oxy]heptyl phenyl carbonate, {[({5-[(ethoxycarbonyl)oxy]pentyl(oxy)carbonyl]oxy (ethane, 2-methyl-l-({[(5-{[(2- methylpropoxy)carbonyl]oxy(pentyl)oxy]carbonyl(oxy (propane, l-{[({5- [(butoxycarbonyl)oxy]pentyl(oxy)carbonyl]oxy (butane, 5-[(phenoxycarbonyl)oxy]pentyl phenyl carbonate, [({3-[(ethoxycarbonyl)oxy]propoxy(carbonyl)oxy]ethane, 2-methyl-l-{[(3-{[(2- methylpropoxy)carbonyl]oxy(propoxy)carbonyl]oxy (propane, l-[({3- [(butoxycarbonyl)oxy]propoxy(carbonyl)oxy]butane, 3-[(phenoxycarbonyl)oxy]propyl phenyl carbonate, {[({8-[(ethoxycarbonyl)oxy]octyl(oxy)carbonyl]oxy (ethane, l-{[({8- [(butoxycarbonyl)oxy]octyl(oxy)carbonyl]oxy (butane, 2-methyl-l-({[(8-{[(2- methylpropoxy)carbonyl]oxy(octyl)oxy]carbonyl(oxy)propane, 8-[(phenoxycarbonyl)oxy]octyl phenyl carbonate, {[({ 10-[(ethoxycarbonyl)oxy]decyl(oxy)carbonyl]oxy(ethane, 2-methyl-l- ({[(10-{[(2-methylpropoxy)carbonyl]oxy(decyl)oxy]carbonyl(oxy (propane, l-{ [({ 10- [(butoxycarbonyl)oxy]decyl(oxy)carbonyl]oxy (butane, 10-[(phenoxycarbonyl)oxy]decyl phenyl carbonate or a mixture thereof.

[0057] Preferred activity limiting agent (ALA) is selected from the group comprising of 2,4- bis[(ethoxycarbonyl)oxy]pentane, {[({4-[(phenoxycarbonyl)oxy]pentan-2- yl(oxy)carbonyl]oxy (benzene, {[({7-[(ethoxycarbonyl)oxy]heptyl(oxy)carbonyl]oxy (ethane, {[({5-[(ethoxycarbonyl)oxy]pentyl(oxy)carbonyl]oxy(ethane or a mixture thereof.

[0058] Suitable selectivity control agents (SCA) are selected from the group comprising of an alkoxysilane, an amine, an ether, a carboxylate, a ketone, an amide, a carbamate, a phosphine, a phosphate, a phosphite, a sulfonate, a sulfone, a sulfoxide, or a mixture thereof, preferably an alkoxysilane.

[0059] Preferred selectivity control agents (SCA) is selected from the group comprising of dicyclopentyldimethoxysilane, di-tert-butyldimethoxysilane, methylcyclohexyldimethoxysilane, ethylcyclohexyldimethoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, di-n- propyldimethoxysilane, diisobutyldimethoxysilane, di-n-butyldimethoxysilane, cyclopentyltrimethoxysilane, isopropyltrimethoxysilane, n-propyltrimethoxysilane, n- propyltriethoxysilane, ethyltriethoxysilane, cyclopentylpyrrolidinodimethoxysilane, bis(pyrrolidino)-dimethoxysilane, bis(perhydroisoquinolino)dimethoxysilane, or a mixture thereof.

[0060] An especially preferred SCA is di(isopropyl)dimethoxysilane, n- propyltrimethoxysilane, or a mixture thereof. An especially preferred combination of SCA and ALA is an alkoxysilane based SCA selected from the group comprising of di(isopropyl)dimethoxysilane, n- propyltrimethoxysilane, or a mixture thereof and an ALA selected from the group comprising of 2,4- bis[(ethoxycarbonyl)oxy]pentane, {[({4-[(phenoxycarbonyl)oxy]pentan-2- yl}oxy)carbonyl]oxy (benzene, {[({7-[(ethoxycarbonyl)oxy]heptyl}oxy)carbonyl]oxy (ethane, {[({5-[(ethoxycarbonyl)oxy]pentyl(oxy)carbonyl]oxy(ethane or a mixture thereofor a mixture thereof.

[0061] Preferred SCA / ALA mixtures according to the invention are those comprising an SCA / ALA mixture comprising 1 to 99.9 wt % SCA and 99 to 0.1 wt % ALA, preferably 1 to 99 wt % SCA and 9 to 1 wt % ALA, preferably 80 to 99 wt % SCA and 20 to 1 wt % ALA, preferably 70 to 99 wt % SCA and 30 to 1 wt % ALA, preferably 60 to 99 wt % SCA and 40 to 1 wt % ALA, preferably 50 to 99 wt % SCA and 50 to 1 wt % ALA, preferably 40 to 99 wt % SCA and 60 to 1 wt % ALA, preferably 30 to 99 wt % SCA and 70 to 1 wt % ALA, preferably 20 to 99 wt % SCA and 80 to 1 wt % ALA, more preferably 10 to 99 wt % SCA and 90 to 1 wt % ALA,

[0062] Preferably, the process of the invention is a gas phase polymerization process. Preferably, the process of the invention is performed in at least one horizontal and / or vertical gas phase reactor. Such reactor may contain mechanical stirring.

[0063] Internal Donor

[0064] Non-limiting examples of suitable internal donors are internal donor is selected from a group consisting at least one of aminobenzoates, succinates, silyl esters, silyl diol esters, diethers, phthalates or any combinations thereof.

[0065] The internal donor is selected from the group consisting of one of more compounds of Formula (II), Formula (III), Formula (IV) or a combination thereof.

[0066] The internal donor is selected from the group, consisting of aminobenzoates represented by formula (II):

[0067] Formula (II) wherein:

[0068] R80is independently selected from a substituted or unsubstituted aryl, aralkyl, or alkylaryl groups, and one or more combinations thereof and

[0069] R81, R82, R83, R84, R85, and R86are each independently selected from a hydrogen or a linear, branched or cyclic hydrocarbyl group, selected from alkyl, alkenyl, aryl, aralkyl, or alkylaryl groups, and one or more combinations thereof, preferably having from 1 to 20 carbon atoms; wherein R87is selected from a group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, phenyl, benzyl, substituted benzyl and halophenyl group; and wherein R88is selected from the group consisting of hydrogen or a linear, branched or cyclic hydrocarbyl group, selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof, preferably having from 1 to 20 carbon atoms, and more preferably R88is phenyl.

[0070] The internal donor is selected from the group consisting of 4-[benzoyl(methyl)amino]pentan-2-yl benzoate; 2,2,6,6-tetramethyl-5-(methylamino)heptan-3-ol dibenzoate; 4-[benzoyl (ethyl)amino]pentan-2-yl benzoate, 4-(methylamino)pentan-2-yl bis (4-methoxy)benzoate), 3- [benzoyl(cyclohexyl)amino]-l -phenylbutyl benzoate, 3-[benzoyl(propan-2-yl)amino]-l- phenylbutyl, 4-[benzoyl(methyl)amino]- 1 ,1,1 -trifluoropentan-2-yl, 3 -(methylamino)- 1,3- diphenylpropan-l-ol dibenzoate, 3-(methyl)amino-propan-l-ol dibenzoate; 3-(methyl)amino-2,2- dimethylpropan-l-ol dibenzoate or 4-(methylamino)pentan-2-yl bis (4-methoxy)benzoate) or a combination thereof. or wherein the internal donor is selected from the group consisting of diethers according to Formula (III),

[0071] Formula (III) wherein R51and R52are each independently selected from a hydrogen or a hydrocarbyl group selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof.

[0072] R53and R54are each independently selected from hydrogen, a halide or a hydrocarbyl group, selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof.

[0073] Preferably, R53and R54are CH3, R51is a secondary alkyl group and R52is a non-secondary alkyl group having at least 5 carbon atoms, preferably R52is a non-secondary alkyl group being branched at the 3-position or further positions or preferably R52is having at most seven carbon atoms, preferably at most six carbon atoms, preferably iso-propyl, iso-butyl, iso-pentyl, cyclopentyl, n- pentyl, and iso-hexyl, preferably R2is being branched at the 3-position or further positions.

[0074] Suitable examples of dialkyl di ether compounds include 1,3 -dimethoxypropane, 1,3- diethoxypropane, 1,3-dibutoxypropane, l-methoxy-3-ethoxypropane, l-methoxy-3- butoxypropane, l-methoxy-3 -cyclohexoxypropane, l-methoxy-2-(methoxymethyl)-5- methylhexan-2-yl)cyclopentane, 2, 2-dimethyl- 1,3 -dimethoxypropane, 2,2-diethyl-l,3- dimethoxypropane, 2, 2-di-n-butyl- 1,3 -dimethoxypropane, 2,2-diiso-butyl-l,3-dimethoxypropane, 2-ethyl-2-n-butyl-l,3-dimethoxypropane, 2-n-propyl-2-cy cl opentyl- 1,3 -dimethoxypropane, 2,2- dimethyl-l,3-diethoxypropane, 2-n-propyl-2-cyclohexyl-l,3-diethoxypropane, 2-(2-ethylhexyl)- 1,3-dimethoxypropane, 2-isopropyl-l,3-dimethoxypropane, 2-n-butyl- 1,3 -dimethoxypropane, 2- sec-butyl- 1,3 -dimethoxypropane, 2-cyclohexyl-l,3-dimethoxypropane, 2-phenyl-l,3- diethoxypropane, 2-cumyl- 1,3 -di ethoxypropane, 2-(2-phenyllethyl)-l,3-dimethoxypropane, 2-(2- cyclohexylethyl)- 1,3 -dimethoxypropane, 2-(p-chlorophenyl)-l,3-dimethoxypropane, 2- (diphenylmethyl)- 1 ,3 -dimethoxypropane, 2-(l -naphthyl)- 1 ,3 -dimethoxypropane, 2-

[0075] (fluorophenyl)- 1,3 -dimethoxy propane, 2-(l -decahydronaphthyl)- 1,3-dimethoxypropane, 2-(p-t- butylphenyl)-l,3-dimethoxypropane, 2, 2-di cyclohexyl- 1,3 -dimethoxypropane, 2,2-di-npropyl- 1,3 -dimethoxypropane, 2-methyl-2-n-propyl- 1 ,3 -dimethoxypropane, 2-methyl-2 -benzyl- 1,3- dimethoxypropane, 2-methyl-2-ethyl- 1 ,3 -dimethoxypropane, 2-methyl-2-phenyl- 1,3- dimethoxypropane, 2-methyl-2-cyclohexyl-l,3-dimethoxypropane, 2,2-bis(pchlorophenyl)-l,3- dimethoxypropane, 2,2-bis(2-cyclohexylethyl)- 1 ,3 -dimethoxypropane, 2-methyl-2-isobutyl- 1,3- dimethoxypropane, 2-methyl-2-(2-ethylhexyl )- 1,3 -dimethoxy propane, 2-methyl-2-isopropyl-

[0076] 1,3 -dimethoxypropane, 2,2-diphenyl- 1 , 3 -dimethoxypropane, 2,2-dibenzyl-l,3- dimethoxypropane, 2.2-bis(cyclohexylmethyl)-l,3-dimethoxypropane, 2,2-diisobutyl-l,3- diethoxypropane, 2.2-diisobuty 1-1,3 -di-n-butoxypropane, 2-isobutyl-2-isopropyl-l,3- dimethoxypropane, 2,2-di-sec-butyl- 1 ,3 -dimethoxypropane, 2,2-di-t-butyl- 1,3- dimethoxypropane, 2.2-dineopentyl-l,3-dimethoxypropane, 2-isopropyl-2-isopentyl-l,3- dimethoxypropane, 2-phenyl-2 -benzyl- 1,3-dimethoxypropane, 2-cyclohexyl-2- cy cl ohexylmethyl- 1,3 -dimethoxypropane, 2-isopropyl-2-(3,7-dimethyloctyl)l,3- dimethoxypropane, 2,2-diisopropyl-l,3-dimethoxypropane, 2-isopropyl-2-cyclohexylmethyl-l,3 - dimethoxypropane, 2,2-diisopentyl- 1 ,3 -dimethoxypropane, 2-isopropyl-2-cyclohexyl- 1,3- dimethoxypropane, 2-isopropyl-2-cyclopentyl-l,3-dimethoxypropane, 2,2-dicylopentyl-l,3- dimethoxypropane, 2-n-heptyl-2-n-pentyl-l,3-dimethoxypropane, 9,9- bis(methoxymethyl)fluorene (flu), l,3-dicyclohexyl-2,2-bis(methoxymethyl)propane, 3,3- bi s(methoxymethyl)-2, 5 -dimethylhexane, 3,3-bis(methoxymethyl)-2,6-dimethyl heptane, 3,3- bis(methoxymethyl)-2,7-dimethyloctane, 3,3-bis(methoxymethyl)-2-methyloctane, 3,3- bis(methoxymethyl)-2,6-dimethyloctane or any combination of the foregoing.

[0077] Examples of preferred diethers are diethyl ether, dibutyl ether, diisoamyl ether, anisole and ethylphenyl ether, 2,3 -dimethoxypropane, 2,3 -dimethoxypropane, 2-ethyl-2-butyl-l, 3- dimethoxypropane, 2-isopropyl-2-isopentyl-l,3-dimethoxypropane (IPIPEN), 9,9-bis (methoxymethyl)fluorene (flu) of formula (IV):

[0078] Formula (IV) or wherein, the internal donor is selected from the group consisting of succinates according to Formula (V)

[0079] Formula (V)

[0080] R60and R61are each independently a hydrocarbyl group, selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof. Said hydrocarbyl group may be linear, branched or cyclic. Said hydrocarbyl group may be substituted or unsubstituted. Said hydrocarbyl group may contain one or more heteroatoms. Preferably, said hydrocarbyl group has from 1 to 10 carbon atoms, more preferably from 1 to 8 carbon atoms, even more preferably from 1 to 6 carbon atoms.

[0081] R62, R63, R64and R65are each independently selected from hydrogen or a hydrocarbyl group, selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof. Said hydrocarbyl group may be linear, branched or cyclic. Said hydrocarbyl group may be substituted or unsubstituted. Said hydrocarbyl group may contain one or more heteroatoms. Preferably, said hydrocarbyl group has from 1 to 20 carbon atoms.

[0082] Preferably, according to the invention, the catalyst system is phthalate free . It is preferred to use so-called phthalate free internal donors because of increasingly stricter government regulations about the maximum phthalate content of polymers. In the context of the present invention, “ “phthalate-free” means having a phthalate content of less than for example 150 ppm, alternatively less than for example 100 ppm, alternatively less than for example 50 ppm, alternatively for example less than 20 ppm, for example of 0 ppm based on the total weight of the catalyst system. Examples of phthalates include but are not limited to a dialkylphthalate esters in which the alkyl group contains from about two to about ten carbon atoms. Examples of phthalate esters include but are not limited to diisobutylphthalate, ethylbutylphthalate, diethylphthalate, di-n- butylphthalate, bis(2-ethylhexyl)phthalate, and diisodecylphthalate.

[0083] Therefore, preferably, the process of the invention is essentially phthalate free.

[0084] An activator that may be added in the catalyst system is selected from a group comprising of benzamide, alkylbenzoates, monoesters or any combinations thereof. Preferably, the activator is benzamide, alkylbenzoates or a combination thereof.

[0085] The molar ratio of the internal electron donor relative to the magnesium may vary between wide limits, for instance from 0.02 to 0.75. Preferably, this molar ratio is from 0.05 to 0.4; more preferably from 0.1 to 0.4; and most preferably from 0.1 to 0.3.

[0086] The molar ratio of the activator relative to the magnesium may vary between wide limits, for instance from 0.02 to 0.5. Preferably, this molar ratio is from 0.05 to 0.4; more preferably from 0.1 to 0.3; and most preferably from 0.1 to 0.2.

[0087] Co-catalyst

[0088] The co-catalyst may include any compounds known in the art to be used as “co-catalysts”, such as hydrides, alkyls, or aryls of aluminum, lithium, zinc, tin, cadmium, beryllium, magnesium, and combinations thereof. The co-catalyst may be a hydrocarbyl aluminum co-catalyst represented by the formula R2O3A1.

[0089] R20is independently selected from a hydrogen or a hydrocarbyl, selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof. Said hydrocarbyl group may be linear, branched or cyclic. Said hydrocarbyl group may be substituted or unsubstituted. Said hydrocarbyl group may contain one or more heteroatoms. Preferably, said hydrocarbyl group has from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, even more preferably from 1 to 6 carbon atoms. On the proviso that at least one R20is a hydrocarbyl group. Optionally, two or three R20groups are joined in a cyclic radical forming a heterocyclic structure.

[0090] Non-limiting examples of suitable R20groups are: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, 2-methylpentyl, heptyl, octyl, isooctyl, 2-ethylhexyl, 5,5- dimethylhexyl, nonyl, decyl, isodecyl, undecyl, dodecyl, phenyl, phenethyl, methoxyphenyl, benzyl, tolyl, xylyl, naphthyl, methylnapthyl, cyclohexyl, cycloheptyl, and cyclooctyl.

[0091] Suitable examples of the hydrocarbyl aluminum compounds as co-catalyst include triisobutylaluminum, trihexylaluminum, di-isobutylaluminum hydride, dihexylaluminum hydride, isobutylaluminum dihydride, hexylaluminum dihydride, diisobutylhexylaluminum, isobutyl dihexylaluminum, trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tri-n-butylaluminum, trioctylaluminum, tridecylaluminum, tridodecylaluminum, tribenzylaluminum, triphenylaluminum, trinaphthylaluminum or tritolylaluminum. In an embodiment, the cocatalyst is selected from triethylaluminum, triisobutylaluminum, trihexylaluminum, di-isobutylaluminum hydride and dihexylaluminum hydride. More preferably, trimethylaluminium, triethylaluminium, triisobutylaluminium, and / or tri octyl aluminium. Most preferably, triethylaluminium (abbreviated as TEAL).

[0092] Other non-limiting examples of suitable co-catalysts include tetraethyl-dialuminoxane, methylaluminoxane, isobutylaluminoxane, tetraisobutyl-dialuminoxane, diethylaluminumethoxide, diisobutylaluminum chloride, methylaluminum dichloride, diethylaluminum chloride, ethylaluminum dichloride and dimethylaluminum chloride.

[0093] Preferably, the co-catalyst is triethylaluminum. The molar ratio of aluminum to titanium may be from about 5: 1 to about 500: 1 or from about 10: 1 to about 200: 1 or from about 15: 1 to about 150: 1 or from about 20: 1 to about 100:1. The molar ratio of aluminum to titanium is preferably about 45: 1.

[0094] For example, the molar ratio of aluminium to titanium, when the co-catalyst is triethylaluminium (Al / Ti ratio) ranges from 25 to 250.

[0095] External Donor An external electron donor may also be present in the catalyst system according to the present invention. One of the functions of an external donor compound is to affect the stereoselectivity of the catalyst system in polymerization of olefins having three or more carbon atoms.

[0096] In the invention, the external donor is a combination of one or more Selectivity Control Agents (SCA) and one or more Activity Limiting Agents (ALA).

[0097] Preferably, the external donor or Selectivity Control Agent (SCA) is selected from the group consisting of dicyclopentyldimethoxysilane, di-tert-butyldimethoxysilane, methylcyclohexyldimethoxysilane, ethylcyclohexyldimethoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, di-n-propyldimethoxysilane, diisobutyldimethoxysilane, di-n- butyldimethoxysilane, cyclopentyltrimethoxysilane, isopropyltrimethoxysilane, n- propyltrimethoxysilane, n-propyltriethoxysilane, ethyltriethoxysilane, tetramethoxysilane, tetraethoxy silane, cyclopentylpyrrolidinodimethoxysilane, bis(pyrrolidino)-dimethoxysilane, diethylaminotriethoxysilane, bis(perhydroisoquinolino)dimethoxysilane, tetraethyl orthosilicate, tetramethyl orthosilicate, tetramethoxyethoxy orthosilicate, or a mixture thereof. More preferably the SCA is selected from the group consisting of di(isopropyl)dimethoxysilane, n- propyltrimethoxysilane, tetraethyl orthosilicate, tetramethyl orthosilicate, or a mixture thereof.

[0098] For example, the external donor in the catalyst system according to the present invention may be complexed with the co-catalyst and mixed with the procatalyst (pre-mix) prior to contact between the procatalyst and the olefin. The external donor can also be added independently to the polymerization reactor. The procatalyst, the co-catalyst, and the external donor can be mixed or otherwise combined prior to addition to the polymerization reactor.

[0099] The procatalyst of the present invention may be produced by any method known in the art.

[0100] The procatalyst may also be produced as disclosed in WO96 / 32426A; this document discloses a process for the polymerization of propylene using a catalyst comprising a catalyst component obtained by a process wherein a compound with formula Mg(OAlk)xQywherein x is larger than 0 and smaller than 2, y equals 2-x and each Aik, independently, represents an alkyl group, is contacted with a titanium tetraalkoxide and / or an alcohol in the presence of an inert dispersant to give an intermediate reaction product and wherein the intermediate reaction product is contacted with titanium tetrachloride in the presence of an internal donor, which is di-n-butyl phthalate. Preferably, the Ziegler-Natta type procatalyst in the catalyst system according to the present invention is obtained by the process as described in WO2007 / 134851A1. In Example I the process is disclosed in more detail. Example I including all sub-examples (IA-IE) is incorporated into the present description. More details about the different embodiments are disclosed starting on page 3, line 29 to page 14 line 29. These embodiments are incorporated by reference into the present description.

[0101] In another embodiment of the present invention, the catalyst system of the present invention comprises the Ziegler-Natta procatalyst as obtained by the process comprising the steps of: i) contacting a compound R4zMgX42-z with an alkoxy- or aryloxy-containing silane compound to give a first intermediate reaction product, being a solid Mg(OR5)xX12-x, wherein: R5is a linear, branched or cyclic hydrocarbyl group independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof; wherein the hydrocarbyl group may be substituted or unsubstituted, may contain one or more heteroatoms and preferably has from 1 to 20 carbon atoms; wherein R4is a linear, branched or cyclic hydrocarbyl group independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof; wherein the hydrocarbyl group may be substituted or unsubstituted, may contain one or more heteroatoms and preferably has from 1 to 20 carbon atoms, preferably R4is butyl; wherein X2and X1are each independently selected from the group comprising of fluoride (F-), chloride (C1-), bromide (Br-) or iodide (I-), preferably chloride; z is in a range of larger than 0 and smaller than 2, being 0 < z < 2; ii) optionally contacting the solid Mg(OR5)xX12-x obtained in step i) with at least one activating compound selected from the group formed by activating electron donors and metal alkoxide compounds of formula M1(OR6)v-w(OR7)w or M2(OR6)v-w(R7)w, to obtain a second intermediate product; wherein: M1is a metal selected from the group comprising of Ti, Zr, Hf, Al or Si; v is the valency of M1; M2is a metal being Si; v is the valency of M2; R6and R7are each a linear, branched or cyclic hydrocarbyl group independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof; wherein the hydrocarbyl group may be substituted or unsubstituted, may contain one or more heteroatoms, and preferably has from 1 to 20 carbon atoms; wherein w is smaller than v, preferably v being 3 or 4; iii) contacting the first or second intermediate reaction product, obtained respectively in step i) or ii), with a halogen-containing Ti-compound and the internal donor.

[0102] According to an aspect, the invention provides a catalyst system for polymerization of polyolefins preferably polypropylene based polymer comprising: a. one or more Ziegler-Natta procatalyst compositions; b. one or more internal donors in the one or more Ziegler-Natta procatalyst compositions; c. one or more cocatalysts, preferably an aluminum containing cocatalyst; d. one or more external donors comprising a mixture of i. one or more selectivity control agents (SC A); ii. one or more activity limiting agents (ALA); wherein the activity limiting agent (ALA) is selected from 2,4-bis[(ethoxycarbonyl)oxy]pentane, 2, 4-bis({[(2-methylpropoxy)carbonyl]oxy ((pentane, 2,4-bis[(butoxycarbonyl)oxy]pentane, {[({4-[(phenoxycarbonyl)oxy]pentan-2-yl(oxy)carbonyl]oxy (benzene, {[({7- [(ethoxycarbonyl)oxy]heptyl}oxy)carbonyl]oxy} ethane, 2-methyl-l-({[(7-{[(2- methylpropoxy)carbonyl]oxy(heptyl)oxy]carbonyl(oxy (propane, l-{[({7- [(butoxycarbonyl)oxy]heptyl(oxy)carbonyl]oxy (butane, 7-[(phenoxycarbonyl)oxy]heptyl phenyl carbonate, {[({5-[(ethoxycarbonyl)oxy]pentyl(oxy)carbonyl]oxy (ethane, 2-methyl-l-({[(5-{[(2- methylpropoxy)carbonyl]oxy(pentyl)oxy]carbonyl(oxy (propane, l-{[({5- [(butoxycarbonyl)oxy]pentyl(oxy)carbonyl]oxy (butane, 5-[(phenoxycarbonyl)oxy]pentyl phenyl carbonate, [({3-[(ethoxycarbonyl)oxy]propoxy(carbonyl)oxy]ethane, 2-methyl-l-{[(3-{[(2- methylpropoxy)carbonyl]oxy(propoxy)carbonyl]oxy (propane, l-[({3- [(butoxycarbonyl)oxy]propoxy(carbonyl)oxy]butane, 3-[(phenoxycarbonyl)oxy]propyl phenyl carbonate, {[({8-[(ethoxycarbonyl)oxy]octyl(oxy)carbonyl]oxy (ethane, l-{[({8- [(butoxycarbonyl)oxy]octyl(oxy)carbonyl]oxy (butane, 2-methyl-l-({[(8-{[(2- methylpropoxy)carbonyl]oxy(octyl)oxy]carbonyl(oxy)propane, 8-[(phenoxycarbonyl)oxy]octyl phenyl carbonate, {[({10-[(ethoxycarbonyl)oxy]decyl(oxy)carbonyl]oxy(ethane, 2-methyl-l- ({[(10-{[(2-methylpropoxy)carbonyl]oxy(decyl)oxy]carbonyl(oxy (propane, !-{[({ 10- [(butoxycarbonyl)oxy]decyl}oxy)carbonyl]oxy (butane, 10-[(phenoxycarbonyl)oxy]decyl phenyl carbonate or a mixture thereof.

[0103] The invention further relates to the process for the production of a propylene homopolymer or mixture of propylene or one or more propylene copolymers.

[0104] Present invention also relates to the process of producing the catalyst composition obtainable by a process comprising the steps of: A) providing the Ziegler-Natta procatalyst obtained by contacting a magnesium- containing support with i) a halogen-containing titanium compound and ii) and an internal donor; and B) contacting said Ziegler-Natta procatalyst obtained in step A) with the aluminum containing cocatalyst and the selectivity control agent (SCA) in combination with the activity limiting agent (ALA) to obtain said catalyst composition.

[0105] The present invention also relates to a polyolefin, preferably a polypropylene obtained or obtainable by a process, comprising contacting an olefin, preferably propylene or a mixture of propylene and ethylene with the catalyst according to the present invention. The terms polypropylene and propylene-based polymer are used herein interchangeable. The polypropylene may be a propylene homopolymer or a mixture of propylene and ethylene, such as a propylene- based copolymer, e.g. heterophasic propylene-olefin copolymer; random propylene-olefin copolymer, preferably the olefin in the propylene-based copolymers being a C2, or C4-C6 olefin, such as ethylene, butylene, pentene or hexene. Such propylene-based (co)polymers are known to the skilled person in the art; they are also described herein above.

[0106] Several types of polyolefins are prepared such as homopolyolefms, random copolymers and heterophasic polyolefin.

[0107] In yet another aspect, the invention relates to a biaxially oriented polypropylene (BOPP) film comprising the propylene homopolymer or propylene-ethylene copolymer of the invention.

[0108] In yet another aspect, the invention relates to the use of the propylene homopolymer or propyleneethylene copolymer obtained or obtainable by the process of the invention for the preparation of an article, for example for the preparation of a biaxially oriented polypropylene (BOPP) film.

[0109] In one embodiment according to the present invention a heterophasic polypropylene having a matrix phase or either homopolymer of polypropylene or a random copolymer of propylene and ethylene and a dispersed phase of ethylene propylene rubber. This is called “impact polypropylene”. For such a polymer, properties such as stiffness and impact may be important.

[0110] The content of the comonomer used in addition to propylene (e.g. ethylene or C4-C6-olefin) may vary from 0 to 8 wt.% based on the total weight of the polymer, preferably from 1 to 4 wt.%.

[0111] In yet another aspect, the invention relates to a process for the preparation of a biaxially oriented polypropylene (BOPP) film, comprising the steps of (a) providing the propylene homopolymer and / or the propylene-ethylene copolymer of the invention and, b) stretching the propylene homopolymer and / or the propylene-ethylene copolymer of step a) in machine direction (MD) and transverse direction (TD).

[0112] The invention also relates to the use of the polyolefins, preferably the propylene-based polymers (also called polypropylenes) according to the invention in injection moulding, blow moulding, extrusion moulding, compression moulding, casting, thin-walled injection moulding, etc. for example in food contact applications.

[0113] The invention will be further elucidated with the following examples without being limited hereto.

[0114] Examples:

[0115] Preparation of the catalyst

[0116] Step A) Butyl Grignard formation

[0117] A 1.7 L stirred flask, fitted with a reflux condenser and a funnel, was filled with magnesium powder (40.0 g, 1.65 mol). The flask was brought under nitrogen. The magnesium was dried at 80°C for 2 hours under nitrogen purge, after which dibutyl ether (200 ml), iodine (0.05 g) and n- chlorobutane (10 ml) were successively added and stirred at 120 rpm. The temperature was maintained at 80°C and a mixture of n-chlorobutane (146 ml) and dibutyl ether (1180 ml) was slowly added over 3 hours. The reaction mixture was stirred for another 3 hours at 80°C. Then the stirring and heating were stopped and the small amount of solid material was allowed to settle for 24 hours. By decanting the colourless solution above the precipitate, a solution of butylmagnesiumchloride with a concentration of 0.90 mol Mg / L was obtained.

[0118] Step B) Preparation of the first intermediate reaction product The solution of reaction product of step A (500 ml, 0.45 mol Mg) and 260 ml of a solution of tetraethoxy silane (TES) in dibutyl ether (DBE), (47 ml of TES and 213 ml of DBE), were cooled to 5°C, and then were fed simultaneously to a mixing device (minimixer) of 0.45 ml volume equipped with a stirrer and jacket. The minimixer was cooled to 5°C by means of cold water circulating in the minimixer's jacket. The stirring speed in the minimixer was 1000 rpm. From the mixing device, the mixed components were directly dosed into a 1.3 liter reactor fitted with blade stirrer and containing 350 ml of dibutyl ether. The dosing temperature of the reactor was 35 °C and the dosing time was 360 min. The stirring speed in the reactor was 250 rpm at the beginning of dosing and was gradually increased up to 450 rpm at the end of dosing stage. On completion of the dosing, the reaction mixture was heated up to 60°C in 30 minutes and held at this temperature for 1 hour. Then the stirring was stopped and the solid substance was allowed to settle. The supernatant was removed by decanting. The solid substance was washed three times using with 700 ml of heptane at a reactor temperature of 50°C for three times. A pale yellow solid substance, reaction product B (the solid first intermediate reaction product; the support), was obtained upon drying with a nitrogen purge. The average particle size of support was 20 microns.

[0119] Step C) Preparation of the second intermediate reaction product

[0120] In inert nitrogen atmosphere at 20°C in a 1000 ml glass flask equipped with a mechanical agitator was filled with 50 g of reaction product B, dispersed in 500 ml of heptane and stirred at 250 rpm. Subsequently, a solution of 2.7 ml ethanol (EtOH / Mg=0.1) in 20 ml heptane was dosed under stirring during 1 hour. After keeping the reaction mixture at 20°C for 30 minutes, a solution of 9.5 ml titanium tetraethoxide (TET / Mg=0.1) in 20 ml of heptane was added for 1 hour. The slurry was slowly allowed to warm up to 30°C over 30 minutes and held at that temperature for another 2 hours. Finally, the supernatant liquid was decanted from the solid reaction product (the second intermediate reaction product C; first activated support) which was washed once with 500 ml of heptane at 30°C and dried using a nitrogen purge.

[0121] Step D) Preparation of the third intermediate reaction product

[0122] In inert nitrogen atmosphere at 25°C in a 1000 ml glass flask equipped with a mechanical agitator was filled with 50 g of second intermediate reaction product C dispersed in 500 ml of heptane and stirred at 250 rpm. Subsequently, a solution of 6.3 ml ethanol (EtOH / Mg=0.3), 20.8 ml of toluene and 37.5 ml of heptane was dosed at 25°C under stirring during 1 hour. The slurry was slowly allowed to warm up to 30°C over 30 minutes and held at that temperature for another 3 hours. Finally, the supernatant liquid was decanted from the solid reaction product (the third intermediate reaction product D; second activated support) which was washed once with 500 ml of heptane at 25°C and dried using a nitrogen purge.

[0123] Step E) is carried out as follows.

[0124] A 300 ml reactor-filter flask was brought under nitrogen and 125 mL of titanium tetrachloride was added, then 5.5 g of second activated support in 15 ml of heptane was added to the reactor. The contents of the reactor were stirred for 60 minutes at room 25°C. Then, 1.78 ml of ethylbenzoate, EB (EB / Mg=0.30 molar ratio) in 4 ml of chlorobenzene was added to the reactor in 30 minutes. Temperature of reaction mixture was increased to 115°C and then the reaction mixture was stirred at 115°C for 90 minutes (I stage of catalyst preparation). The contents of the flask were filtered, after which the solid product was washed with chlorobenzene (125 ml) at 100 to 105°C for 20 minutes. Then, the contents of the flask were filtered. A mixture of titanium tetrachloride (62.5 ml) and chlorobenzene (62.5 ml) was added to the reactor. The reaction mixture was stirred at 115°C for 60 minutes (II stage of catalyst preparation). Then, the contents of the flask were filtered. A mixture of titanium tetrachloride (62.5 ml) and chlorobenzene (62.5 ml) was added to the reactor. Then, 0.51 g of 4-[benzoyl(methyl)amino]pentan-yl benzoate (AB / Mg = 0.04) in 4 ml of chlorobenzene was added to the reactor in 10 minutes. The reaction mixture was stirred at 115°C for 30 minutes (III stage of catalyst preparation). Then, the contents of the flask were filtered. A mixture of titanium tetrachloride (62.5 ml) and chlorobenzene (62.5 ml) was added to the reactor. The reaction mixture was stirred at 115°C for 30 minutes (IV stage of catalyst preparation). Then, the contents of the flask were filtered. The solid product obtained was washed five times with 125 ml of heptane starting at 60°C with 5 minutes stirring per wash prior to filtration. The temperature was gradually reduced from 60 to 25°C during the washings. Finally, the solid product obtained was dried using a nitrogen purge at a temperature of 25°C for 2 hours.

[0125] Polymerization was performed in PPR reactors.

[0126] Polymerization method PPR reactors (PPR48 by Freeslate and within a triple-housed MBraun glovebox under nitrogen atmosphere) were conditioned with repeated high temperature nitrogen purges, loaded with tared and heat-treated glass vial inserts then heat-treated PEEK disposable stirrers. Solvent and 1 pmol of TEA were added at ambient temperature and pressure through a valve via robotic syringe needles, leak tested under a propylene atmosphere and dosed with 15 psig of 20% H2 / N2 v / v gas at 40°C. The reactors were heated to the desired polymerization temperature (70 or 100°C) with stirring and pressurized to the final total pressure with propylene (67 or 95 psig). Additional TEA as activator (160 Al / Ti), the external donor combination which include SC A and ALA (10 mM in n-heptane), catalyst slurry (between 1-2 mg / mL concentration in 2,2,4,6,6-pentamethyl heptane) and n-heptane were injected via robotic syringe needle to a total volume of 5.00 mL to initiate the polymerization reaction. Propylene is fed into each reactor independently to maintain the target total pressure throughout the duration of the reaction within 2 psig. The reactors were quenched after 20 minutes by a 0.5% v / v O2 / N2 overpressure, cooled, vented and glass inserts removed for vacuum-centrifuge drying. The vials were then robotically-weighed to obtain the yield. Table 1

[0127] ABZEB- Amino Benzoate / Ethyl Benzoate

[0128] IPIPEN / BA- 2-isopropyl-2-isopentyl-l,3-dimethoxypropane / N,N-dimethylbenzamide Same procatalyst is used for all the experiments.

[0129] Methods: Soluble Fraction:

[0130] CEF analysis for determining soluble fractions is used. A Polymer Char CEF device with an IR5 detector was used to determine the soluble fraction and temperature elution maximum. Polymer samples of approximately 20 mg were sealed in a crimp cap vial, purged with nitrogen and robotically diluted with TCB to a concentration of 2 mg / mL. Samples were dissolved with gentle shaking at 160°C for three hours then injected into the column heated to 160°C. The sample is cooled at a flow rate 0.01 mL / min and cooling rate of 8°C / min to a final crystallization temperature of 35°C that is held for one minute. The flow rate is increased to 1 mL / min for one minute then a temperature ramp of 4 °C / min is introduced to a final temperature of 160°C. Activity:

[0131] Activity is determined by the total polymer yield from the reactor divided by the mass of catalyst injected, the total time of the polymerization and the solution propylene concentration. Propylene concentration is determined by the partial pressure of propylene and its Henry coefficients in the solvent. Activity reduction:

[0132] Activity reduction is an index of self-extinguishing property. It indicates that how much of activity is reduced at 100° C when compared to the activity at 70° C. It is measured by using the formula: 100 - (activity at 100° C / activity at 70° C * 100)

[0133] Table 1 demonstrates various examples comprising different SC A / ALA and their effect on the catalyst activity during the polymerisation. CE1 and CE2 show the comparative examples while

[0134] IE1-IE5 show the inventive examples as per the present invention. It is evident from the inventive examples that the desired combinations of SCA / ALA provide the required value of % activity reduction along with the soluble fraction. 4

Claims

Claims1. A catalyst system for polymerization of polyolefins preferably polypropylene based polymer comprising: a. one or more Ziegler-Natta procatalyst compositions; b. one or more internal donors; c. one or more cocatalysts, preferably an aluminum containing cocatalyst; d. one or more external donors comprising a mixture of: i. one or more selectivity control agents (SC A); ii. one or more activity limiting agents (ALA); wherein the activity limiting agent (ALA) is a compound according to formula (I),ztFormula (I) wherein R1and R2are independently selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxycarbonyl or alkylaryl having 1 to 15 carbon atoms; wherein R3is a linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl or alkylaryl having 1 to 10 carbon atoms or R3 is represented by -O-R4-O- or -O-R4- wherein R4is selected from a group of linear or branched chains of substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 10 carbon atoms.

2. Catalyst system according to claim 1, wherein the activity limiting agent (ALA) is a compound according to formula (I)Formula (I)wherein R1and R2having preferably 1-12 carbon atoms, preferably 1-10 carbon atoms, more preferably 1-8 carbon atoms; wherein R3having preferably 1 to 8 carbon atoms, more preferably 1-6 carbon atoms.

3. Catalyst system according to any one of the preceding claims, wherein R1and R2are independently selected from a group of linear or branched chains of unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 15 carbon atoms and wherein R3 is represented by -O-R4-O- or -O-R4- wherein R4is selected from a group of linear or branched chains of unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkoxy carbonyl, alkylaryl having 1 to 10 carbon atoms4. Catalyst system according to any one of preceding claims, wherein the activity limiting agent (ALA) is selected from 2,4-bis[(ethoxycarbonyl)oxy]pentane, 2,4-bis({[(2- methylpropoxy)carbonyl]oxy ((pentane, 2,4-bis[(butoxycarbonyl)oxy]pentane, { [({4- [(phenoxycarbonyl)oxy]pentan-2-yl(oxy)carbonyl]oxy (benzene, {[({7- [(ethoxycarbonyl)oxy]heptyl}oxy)carbonyl]oxy} ethane, 2-methyl-l-({[(7-{[(2- methylpropoxy)carbonyl]oxy(heptyl)oxy]carbonyl(oxy (propane, l-{[({7- [(butoxycarbonyl)oxy]heptyl(oxy)carbonyl]oxy (butane, 7- [(phenoxycarbonyl)oxy]heptyl phenyl carbonate, {[({5- [(ethoxycarbonyl)oxy]pentyl(oxy)carbonyl]oxy( ethane, 2-methyl-l-({[(5-{[(2- methylpropoxy)carbonyl]oxy(pentyl)oxy]carbonyl(oxy (propane, l-{[({5- [(butoxycarbonyl)oxy]pentyl(oxy)carbonyl]oxy (butane, 5- [(phenoxycarbonyl)oxy]pentyl phenyl carbonate, [({3-[ (ethoxy carbony l)oxy ]propoxy ( carbonyl)oxy] ethane, 2-methyl- 1 - { [(3 - { [(2- methylpropoxy)carbonyl]oxy(propoxy)carbonyl]oxy (propane, l-[({3- [(butoxycarbonyl)oxy]propoxy(carbonyl)oxy]butane, 3-[(phenoxycarbonyl)oxy]propyl phenyl carbonate, {[({8-[(ethoxycarbonyl)oxy]octyl(oxy)carbonyl]oxy(ethane, l-{[({8- [(butoxycarbonyl)oxy]octyl(oxy)carbonyl]oxy (butane, 2-methyl-l-({[(8-{[(2- methylpropoxy)carbonyl]oxy(octyl)oxy]carbonyl(oxy (propane, 8- [(phenoxycarbonyl)oxy]octyl phenyl carbonate, {[({ 10- [(ethoxycarbonyl)oxy]decyl(oxy)carbonyl]oxy (ethane, 2-methyl-l-({[(10-{[(2- methylpropoxy)carbonyl] oxy } decyl)oxy] carbonyl } oxy)propane, 1 - { [( { 10-[(butoxycarbonyl)oxy]decyl(oxy)carbonyl]oxy (butane, 10-[(phenoxycarbonyl)oxy]decyl phenyl carbonate or a mixture thereof.

5. Catalyst system according to any one of the preceding claims, wherein the selectivity control agent (SCA) is selected from an alkoxysilane, an amine, an ether, a carboxylate, a ketone, an amide, a carbamate, a phosphine, a phosphate, a phosphite, a sulfonate, a sulfone, a sulfoxide, or a mixture thereof, preferably an alkoxysilane, more preferably selected from the group comprising of dicyclopentyldimethoxysilane, di-tert- butyldimethoxysilane, methylcyclohexyldimethoxysilane, ethylcyclohexyldimethoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, di-n-propyldimethoxysilane, diisobutyldimethoxysilane, di-n-butyldimethoxysilane, cyclopentyltrimethoxysilane, isopropyltrimethoxysilane, n-propyltrimethoxysilane, n- propyltri ethoxy silane, ethyltriethoxysilane, cyclopentylpyrrolidinodimethoxysilane, bis(pyrrolidino)-dimethoxysilane, bis(perhydroisoquinolino)dimethoxysilane, or a mixture thereof, even more preferably the selectivity control agent (SCA) is di(isopropyl)dimethoxysilane, n- propyltrimethoxysilane, or a mixture thereof.

6. Catalyst system according to any one of the preceding claims, wherein the selectivity control agent (SCA) is di(isopropyl)dimethoxysilane, n-propyltrimethoxysilane or a mixture thereof and the activity limiting agent (ALA) is selected from the group comprising of 2,4-bis[(ethoxycarbonyl)oxy]pentane, {[({4- [(phenoxycarbonyl)oxy]pentan-2-yl(oxy)carbonyl]oxy (benzene, {[({7- [(ethoxycarbonyl)oxy]heptyl(oxy)carbonyl]oxy (ethane, {[({5- [(ethoxycarbonyl)oxy]pentyl(oxy)carbonyl]oxy(ethane or a mixture thereof.

7. Catalyst system according to any one of the preceding claims comprising an SCA / ALA mixture comprising 1 to 99.9 wt % SCA and 99 to 0.1 wt % ALA, preferably 50 to 98 wt % SCA and 50 to 2 wt % ALA, more preferably 30 to 99 wt % SCA and 70 to 1 wt % ALA, even more preferably 10 to 99 wt % SCA and 90 to 1 wt % ALA.

8. Catalyst system according to any one of the preceding claims wherein the internal donor is selected from a group consisting at least one of aminobenzoates, succinates, silylesters, silyl diol esters, diethers, phthalates, preferably a phthalates free donor or any combinations thereof.

9. Catalyst system according to any one of the preceding claims wherein the cocatalyst is selected from triisobutylaluminum, trihexylaluminum, di-isobutylaluminum hydride, dihexylaluminum hydride, isobutylaluminum dihydride, hexylaluminum dihydride, diisobutylhexylaluminum, isobutyl dihexylaluminum, trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tri-n-butylaluminum, trioctylaluminum, tridecylaluminum, tridodecylaluminum, tribenzylaluminum, triphenylaluminum, trinaphthylaluminum, tritolylaluminum, tetraethyl-dialuminoxane, methylaluminoxane, isobutylaluminoxane, tetraisobutyl-dialuminoxane, diethylaluminumethoxide, diisobutylaluminum chloride, methylaluminum dichloride, diethylaluminum chloride, ethylaluminum dichloride or dimethylaluminum chloride or a mixture thereof, preferably, the co-catalyst is triethylaluminum.

10. Catalyst system according to any one of the preceding claims, wherein the Ziegler-Natta procatalyst as obtained by the process comprising the steps of: i) contacting a compound R4zMgX42-z with an alkoxy- or aryloxy-containing silane compound to give a first intermediate reaction product, being a solid Mg(OR5)xX12-x, wherein: R5is a linear, branched or cyclic hydrocarbyl group independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof; wherein the hydrocarbyl group may be substituted or unsubstituted, may contain one or more heteroatoms and preferably has from 1 to 20 carbon atoms; wherein R4is a linear, branched or cyclic hydrocarbyl group independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof; wherein the hydrocarbyl group may be substituted or unsubstituted, may contain one or more heteroatoms and preferably has from 1 to 20 carbon atoms, preferably R4is butyl; wherein X2and X1are each independently selected from the group comprising of fluoride (F-), chloride (C1-), bromide (Br-) or iodide (I-), preferably chloride; z is in a range of larger than 0 and smaller than 2, being 0 < z < 2; ii) optionally contacting the solid Mg(OR5)xX12-x obtained in step i) with at least one activating compound selected from the group formed by activating electron donors andmetal alkoxide compounds of formula M1(OR6)v-w(OR7)w or M2(OR6)v-w(R7)w, to obtain a second intermediate product; wherein: M1is a metal selected from the group comprising of Ti, Zr, Hf, Al or Si; v is the valency of M1; M2is a metal being Si; v is the valency of M2; R6and R7are each a linear, branched or cyclic hydrocarbyl group independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof; wherein the hydrocarbyl group may be substituted or unsubstituted, may contain one or more heteroatoms, and preferably has from 1 to 20 carbon atoms; wherein w is smaller than v, preferably v being 3 or 4; iii) contacting the first or second intermediate reaction product, obtained respectively in step i) or ii), with a halogen-containing Ti-compound and the internal donor.

11. Catalyst system according to any one of the preceding claims, wherein the selectivity control agent (SCA) is selected from an alkoxysilane, an amine, an ether, a carboxylate, a ketone, an amide, a carbamate, a phosphine, a phosphate, a phosphite, a sulfonate, a sulfone, a sulfoxide, or a mixture thereof, the cocatalyst is selected from triisobutylaluminum, trihexylaluminum, diisobutylaluminum hydride, dihexylaluminum hydride, isobutylaluminum dihydride, hexylaluminum dihydride, diisobutylhexylaluminum, isobutyl dihexylaluminum, trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tri-n- butylaluminum, trioctylaluminum, tridecylaluminum, tridodecylaluminum, tribenzylaluminum, triphenylaluminum, trinaphthylaluminum, tritolylaluminum, tetraethyl-dialuminoxane, methylaluminoxane, isobutylaluminoxane, tetraisobutyl - dialuminoxane, diethyl-aluminumethoxide, diisobutylaluminum chloride, methylaluminum dichloride, diethylaluminum chloride, ethylaluminum dichloride or dimethylaluminum chloride or a mixture thereof, preferably, the co-catalyst is triethylaluminum.

12. Use of catalyst system according to one of the preceding claims, for a polymerization of an olefin based polymer.

13. A polyolefin, preferably a polypropylene, obtained or obtainable by the polymerization according to claim 12.

14. A shaped article, comprising the polyolefin of claim 13.

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