In-situ reactor blend of ziegler-natta catalysed nucleated polypropylene and metallocene catalysed polypropylene

Abstract

A method for preparing isotactic propylene polymer compositions includes, in one or more reaction steps, polymerizing propylene and optionally one or more comonomers selected from ethylene and α-olefins containing 4 to 12 carbon atoms in the presence of a catalyst system comprising 45 to 99 wt% of a metallocene catalyst and 1 to 55 wt% of a Ziegler-Natta catalyst, wherein the Ziegler-Natta catalyst has a non-phthalate internal donor and has been reacted with a catalyst having the general formula CH2=CH-CHR. 1 R 2 (I) monomer (I) prepolymerization, wherein R 1 and R 2 It is a single alkyl group having one or more carbon atoms, or it forms an optionally substituted saturated, unsaturated, or aromatic ring or fused ring system containing 4 to 20 carbon atoms.

Description

TECHNICAL FIELD

[0001] The present invention relates to a process for the preparation of isotactic propylene polymer compositions, wherein a catalyst blend of a Ziegler Natta catalyst free of phthalate esters and a supported metallocene catalyst is employed, the isotactic propylene polymer compositions obtained from the process, and the use of the catalyst blend for the synthesis of isotactic propylene polymer compositions. BACKGROUND

[0002] Polypropylene is one of the most widely used polymers due to its good combination of properties, which makes it suitable for applications ranging from food packaging (films, bottles) to more demanding applications, such as pipes, fittings or foams.

[0003] For these different applications, polymers with very different properties are required. The main characteristics of these polymers are their isotacticity (the stiffness depends to a large extent on the isotacticity), the melt flow rate (MFR) and the molecular weight and molecular weight distribution (MWD), which have a great influence on the processability. These characteristics can be controlled by varying the process conditions and using different catalyst systems.

[0004] The use of Ziegler-Natta type catalysts containing magnesium, titanium and halogen as essential components and metallocene catalysts for propylene polymerization is well known in the art.

[0005] Many documents describe the use of Ziegler-Natta type catalysts alone or more conventionally supported on a support, such as an oxide support, such as silica or alumina. As is well known in the art, such supported catalyst systems are generally used with a metal alkyl cocatalyst and in the presence of a compound as external donor.

[0006] Metallocene catalysts are also widely used and are generally used in combination with a cocatalyst, as is well known in the art.

[0007] Metallocene catalysts for the production of propylene homopolymers or copolymers generally have a good flexibility in the chain structure and therefore also in the crystal structure of the polypropylene product. In addition, they also offer a significant hydrogen response, thus reaching a final melt flow rate (MFR) range, especially a higher melt flow end, which is not achievable with traditional Ziegler-Natta catalysts. This feature is particularly desirable in solving the problem of reducing the organoleptic level, taste and odor, but can also be a problem for products requiring low melt flow rates, such as pipes.

[0008] Another problem associated with metallocene catalyzed polypropylenes is that they generally have weak processability and poorer mechanical properties due to their narrow molecular weight distribution compared to Ziegler-Natta catalyzed products.

[0009] It is also well known to combine different catalysts to form multiple active sites, such as dual active site catalyst systems or mixed catalyst systems. Because each active site in such a catalyst can produce a polymer component having specific properties (e.g., desirable mechanical or optical properties), such catalyst systems provide the skilled polymer chemist with greater latitude to tailor the properties of the polymer product. For example, dual active site or mixed catalyst systems are used in order to obtain a broad multimodal, such as bimodal, molecular weight distribution in the final polymer product. Such a distribution is desirable because higher molecular weight components contribute to the strength of the final product made from the polymer, while lower molecular weight components contribute to the processability of the polymer.

[0010] However, the use of "mixed" catalyst systems is often associated with operability issues. For example, the use of two catalysts on a single support can be associated with a reduced degree of process control flexibility. Furthermore, two different catalyst / co-catalyst systems can interfere with each other - for example, external donor components commonly used in Ziegler-Natta catalyst systems can "poison" metallocene catalysts.

[0011] Accordingly, a "mixed catalyst" process that avoids or at least mitigates some of these difficulties would be a beneficial addition to the art.

[0012] Accordingly, it is desirable to maximize the benefits of each individual catalyst system (i.e., Ziegler-Natta and metallocene).

[0013] Another possibility to reach the desired molecular weight and MWD is to blend two or more polypropylenes, or alternatively by multi-stage polymerization.

[0014] Several multi-stage processes for the polymerization of olefins carried out in two or more reactors are known in the patent literature and are of particular interest in industrial practice because process parameters such as temperature, pressure, type and concentration of monomers, concentration of hydrogen or other molecular weight regulators can be varied independently in any reactor. Different catalyst systems are used in combination, which offers greater flexibility than single-stage processes in controlling the composition and properties of the final product.

[0015] For example, a multi-stage process can be applied to, for example, the preparation of olefin (co)polymers having a broad molecular weight distribution (MWD), for example, by producing polymer species having different molecular weights in the various reactors.

[0016] For example, WO 96 / 11218 discloses a multi-stage process for the polymerization of one or more than one olefin of the formula CH2=CHR, wherein R can be an alkyl group having 1 to 10 carbon atoms. In a first polymerization stage, one or more than one such olefin is polymerized by Ziegler-Natta catalysis to form particles of a first polymer. In a subsequent polymerization stage, a polymer of one or more than one such olefin is formed on or in the particles of the first polymer by metallocene catalysis, whereby the first catalyst is deactivated prior to the introduction of the second catalyst system. However, the transition between the two stages makes the overall process very time-consuming and cost-intensive.

[0017] In particular, the process described in WO 96 / 11218 comprises a first stage in which a propylene polymer is produced in the presence of a titanium or vanadium catalyst, a second stage in which the titanium or vanadium catalyst is deactivated, and a third stage in which the polymerization is continued in the presence of a metallocene catalyst. This cascade process is believed to result in a good homogenization of the resulting polymer blend. However, the first catalyst needs to be deactivated before the polymer particles can be impregnated with the second catalyst, which makes the process unnecessarily complex and not cost-effective. Another disadvantage of the process is that the second catalyst is relatively quickly flushed out of the reactor due to the high production throughput of the polymer material into the third stage of the polymerization process.

[0018] Despite the great progress made in the field of polymerizing propylene to produce polypropylene compositions having an improved distribution of polymer properties, it has not been possible to date to provide propylene homopolymers or copolymers having an improved balance between optical properties, mechanical properties, thermal properties and processing properties.

[0019] To this end, there is still a need for propylene homopolymer or copolymer compositions which meet the various stringent requirements in many end-use fields of polymers, such as packaging, including food and pharmaceutical packaging, fibers, pipes and the automotive industry, thereby exhibiting the desired superior balance between optical properties, mechanical properties, thermal properties and processing properties.

[0020] In particular, the balance between the haze properties and the stiffness of polypropylene can be difficult to achieve, especially at high melt flow rates (i.e. low molecular weight). Furthermore, the synthesis of heterophasic propylene copolymers having very high melt flow rates is not simple, as the hydrogen response of the catalyst during the polymerization of the crystalline matrix is often poor. Therefore, a catalyst or catalyst blend having an improved hydrogen response is advantageous in addition to other beneficial properties. SUMMARY

[0021] The present invention is based on the finding that a catalyst blend of a metallocene catalyst with a phthalate-free Ziegler-Natta type catalyst composition which has been modified with a polymer nucleating agent is able to achieve the above mentioned balance of objectives regarding mechanical and optical properties and hydrogen response.

[0022] The present invention relates to a process for the preparation of isotactic propylene polymer compositions comprising the following steps:

[0023] (a) prepolymerizing a Ziegler-Natta type catalyst comprising a magnesium halide support, a titanium component and an internal donor (ID) with a monomer (I) having the general formula (I) in the presence of an aluminum alkyl cocatalyst and an external donor (ED) to obtain a catalyst composition (II), wherein the internal donor is not a phthalate and the Ziegler-Natta type catalyst is free of phthalates

[0024] CH2=CH-CHR 1 R 2 (I)

[0025] wherein R 1 and R 2 are individual alkyl groups having one or more carbon atoms or form an optionally substituted saturated, unsaturated or aromatic ring or fused ring system containing 4 to 20 carbon atoms, the catalyst composition (II) comprising 25 to 95 wt.-% of isotactic polymer based on the monomer (I);

[0026] (b) mixing the catalyst composition (II) with a supported metallocene catalyst (III) suitable for the production of isotactic polypropylene in a weight ratio (II):(III) of 1 :99 to 55:45 in an inert medium to obtain a catalyst mixture (IV);

[0027] (c) using the catalyst blend (IV) in one or more reaction steps for the polymerization of propylene and optionally one or more comonomers selected from ethylene and a-olefins containing 4 to 12 carbon atoms to obtain an isotactic propylene homo- or copolymer (V);

[0028] (d) melt mixing the isotactic propylene homo- or copolymer (V) with additives such as antioxidants and acid scavengers and optionally nucleating agents followed by pelletization.

[0029] The present invention also relates to an isotactic propylene polymer composition produced according to the process of the present invention.

[0030] In another aspect, the present invention relates to a film or molded article comprising at least 95 wt.-% of the isotactic propylene polymer composition according to the present invention.

[0031] In another aspect, the present application relates to the use of a catalyst mixture for the production of isotactic propylene homopolymers or copolymer compositions, the catalyst mixture comprising:

[0032] (a) 45 to 95 wt.-%, relative to the total weight of the catalyst mixture, of a metallocene catalyst (III) comprising

[0033] (i) a metallocene complex having the general formula (VI)

[0034]

[0035] wherein each X is independently a sigma-donor ligand,

[0036] L is a divalent bridge selected from -R'2C-, -R'2C-CR'2-, -R'2Si-, -R'2Si-SiR'2-, -R'2Ge-, wherein each R'

[0037] is independently a hydrogen atom or a C1-C20-hydrocarbyl group optionally comprising one or more heteroatoms of groups 14-16 of the periodic table, 20 a hydrocarbyl group or a fluorine atom, or optionally two R' groups together can form a ring,

[0038] each R 1 is independently the same or can be different and is a hydrogen, a linear or branched C1-C6-alkyl group, a C 7-20 -arylalkyl group, a C 7-20 -alkylaryl group or a C6-C10-aryl group, 6-20 -aryl group or an OY group, wherein Y is a C 1-10 -hydrocarbyl group, and optionally two adjacent R 1 groups can be part of a ring comprising the phenyl carbon to which they are bonded,

[0039] each R 2 is independently the same or can be different and is a CH2-R 8 group, wherein R 8 is H or a linear or branched C 1-6 -alkyl group, a C 3-8 -cycloalkyl group, a C 6-10 -aryl group,

[0040] R 3 is a linear or branched C1-C6-alkyl group, a C 7-20 -arylalkyl group, a C 7-20 -alkylaryl group or a C6-C 20 -aryl group,

[0041] R 4 is a C(R 9 )3 group, wherein R 9is linear or branched C1-C6-alkyl,

[0042] R 5 is hydrogen or an aliphatic C1-C 20 -hydrocarbyl group optionally containing one or more heteroatoms belonging to group 14 of the periodic table of elements;

[0043] R 6 is hydrogen or an aliphatic C1-C 20 -hydrocarbyl group optionally containing one or more heteroatoms belonging to group 14 of the periodic table of elements; or

[0044] R 5 and R 6 are together able to form a 5-membered saturated carbon ring, which is optionally substituted by n groups R 10 , n being from 0 to 4;

[0045] each R 10 is identical or different and can be a C1-C 20 -hydrocarbyl group, or a C1-C 20 -hydrocarbyl group optionally containing one or more heteroatoms belonging to group 14 of the periodic table of elements;

[0046] R 7 is H or linear or branched C1-C6-alkyl or an aryl or heteroaryl group having from 6 to 20 carbon atoms, which is optionally substituted by 1 to 3 groups R 11 , n being from 0 to 4;

[0047] each R 11 is independently identical or can be different and is hydrogen, linear or branched C1-C6-alkyl, C 7-20 -aralkyl, C 7-20 -alkylaryl or C 6-20 -aryl group or an OY group, wherein Y is C 1-10 -hydrocarbyl group,

[0048] (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and

[0049] (iii) a silica support, and

[0050] (b) from 5 to 55 wt.-%, relative to the total weight of the catalyst mixture, of a Ziegler-Natta type catalyst composition (II) comprising

[0051] i) a Ziegler-Natta type catalyst comprising a magnesium halide support, a titanium component and an internal donor (ID), wherein the internal donor is not a phthalate and the Ziegler-Natta type catalyst does not contain a phthalate;

[0052] ii) an alkyl aluminium cocatalyst;

[0053] iii) an external donor (ED)

[0054] wherein the Ziegler-Natta catalyst composition has been modified by polymerization of monomers (I) having the general formula

[0055] CH2=CH-CHR 1 R 2 (I)

[0056] wherein R 1 and R 2 are individual alkyl groups having one or more carbon atoms, or form an optionally substituted saturated, unsaturated or aromatic ring or fused ring system containing 4 to 20 carbon atoms, such that the Ziegler-Natta catalyst composition (II) contains 25 to 95 wt.-% of isotactic polymer based on said monomers (I)

[0057] The isotactic propylene homo- or copolymer composition has one or more, preferably all, of the following properties:

[0058] (i) a melt flow rate MFR2determined according to ISO 1133 at 230 °C and a load of 2.16 kg in the range of 5 to 500 g / 10 min,

[0059] (ii) a comonomer content of at most 6.0 wt.-%, the comonomer being preferably ethylene,

[0060] (iii) an isotactic pentad fraction as determined by13C-NMR spectroscopy in the range of 96.0 to 99.9 % 13 <mmmm>

[0061] (iv) a 2,1 -regio defect content in the range of 0.2 to 1.2 mol.%, and

[0062] (v) a xylene cold soluble (XCS) content determined according to ISO 16152 at 25 °C in the range of 0.9 to 9.0 wt.-%.

[0063] Definitions

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although, any methods and materials similar or equivalent to those described herein can be used in the practice of the present application, the preferred materials and methods are described herein. In describing and claiming the present application, the following terminology will be used in accordance with the definitions set out below.

[0065] The use of the terms "a" and "an" and "the" and "at least one" are intended to include both singular and plural referents unless otherwise indicated. By way of example, "an" A refers to one A or to more than one A.

[0066] Polymer blend refers to a mixture of two or more polymer components. Typically, a blend can be prepared by mixing two or more polymer components. Suitable mixing procedures known in the art are post-polymerization blending and in-situ blending during the polymerization process. Post-polymerization blending can be dry blending of polymer components such as polymer powders and / or compounded polymer pellets or melt blending of polymer components by melt mixing. During in-situ blending, polymer components can be produced in different stages of a multi-stage polymerization process and blended by polymerizing one polymer component in the presence of another polymer component polymerized in a previous stage (in case the catalysts used for each component are the same). If the catalysts used for the two components are different, as is the case in the present application, in-situ blending is achieved by using a catalyst blend comprising more than one catalyst.

[0067] Propylene homopolymer is a polymer consisting essentially of propylene monomer units. Due to impurities, especially during commercial polymerization processes, propylene homopolymer can comprise up to 0.1 mol.% of comonomer units, preferably up to 0.05 mol.% of comonomer units, most preferably up to 0.01 mol.% of comonomer units.

[0068] ​A propylene random copolymer is a copolymer of propylene monomer units and comonomer units, wherein the comonomer units are randomly distributed over the polymer chain, the comonomer units being preferably selected from ethylene and C4-C12a-olefins. The propylene random copolymer can comprise comonomer units from one or more comonomers differing in the amount of carbon atoms. The amounts are given in % by weight (wt.%) unless otherwise stated.

[0069] A propylene homopolymer and a propylene random copolymer typically have only one glass transition temperature.

[0070] The isotacticity of a polymer is an indicator of the stereo-regularity of stereogenic centers introduced during the polymerization process. In a 100% isotactic polypropylene, all stereogenic centers will have the same configuration. The isotacticity is typically quantified by the meso pentad concentration [mmmm] in percent. Isotactic polymers typically have a meso pentad concentration of at least 90%, more preferably at least 95%, more preferably at least 98%. DETAILED DESCRIPTION

[0071] Ziegler-Natta catalyst composition (II)

[0072] The Ziegler-Natta catalyst composition (II) according to the present application is formed by prepolymerizing a Ziegler-Natta type catalyst (ZN-C) comprising a magnesium halide support, a titanium component and an internal donor (ID), wherein the internal donor is not a phthalate, and the Ziegler-Natta type catalyst is free of phthalates, with a monomer (I) having the general formula

[0073] CH2=CH-CHR 1 R 2 (I)

[0074] wherein R 1 and R 2 are individual alkyl groups having one or more carbon atoms, or form an optionally substituted saturated, unsaturated or aromatic ring or fused ring system containing 4 to 20 carbon atoms, the catalyst composition (II) comprising 25 to 95 wt.% of an isotactic polymer based on the monomer (I).

[0075] The Ziegler-Natta type catalyst (ZN-C) comprises a magnesium halide support, a titanium component and an internal donor (ID).

[0076] The titanium component and the internal donor (ID) are further defined hereinabove and hereinbelow.

[0077] The magnesium halide support can be any magnesium halide component. The use of the term "support" merely indicates that the magnesium halide component supports the active titanium centre at a molecular level. The skilled person will be aware that Ziegler-Natta type catalysts can be classified as supported or self-supported catalysts. The term "supported catalyst" refers to catalysts wherein the magnesium halide support is an external support material provided as magnesium halide itself. Self-supported catalysts, such as those described in WO 2017 / 148970 A1, can be produced from starting materials that do not contain magnesium halide; however, in all cases, the magnesium halide, i.e. the magnesium halide support required by the present application, will be formed during the formation of the Ziegler-Natta type catalyst, typically from the reaction between a magnesium-containing starting material and a titanium halide. Thus, the skilled person will understand that the use of the term "support" in "magnesium halide support" is not intended to limit the present application to Ziegler-Natta type catalysts having an external support material. In fact, it is preferred that the Ziegler-Natta type catalyst does not contain any external support material, i.e. the catalyst is self-supported. Suitable self-supported catalysts are described, for example, in WO 2017 / 148970 A1.

[0078] The Ziegler-Natta type catalyst (ZN-C) can be further defined by the way it is obtained. Thus, the Ziegler-Natta type catalyst (ZN-C) is preferably obtained by a process comprising the steps of

[0079] a)

[0080] a1 ) providing a solution of at least one alkyl magnesium compound (Ax) which is the reaction product of magnesium and an alcohol (A) optionally in an organic liquid reaction medium, the alcohol (A) comprising at least one ether moiety in addition to a hydroxyl moiety;

[0081] or

[0082] a2) at least a solution of an alkyl magnesium compound (Ax') which is the reaction product of a magnesium compound (MC) with an alcohol mixture of an alcohol (A) and a monohydric alcohol (B) of formula ROH optionally in an organic liquid reaction medium;

[0083] or

[0084] a3) providing a solution of a mixture of an alkyl magnesium compound (Ax) and an alkyl magnesium compound (Bx) which is the reaction product of a magnesium compound (MC) and a monohydric alcohol (B) optionally in an organic liquid reaction medium; and

[0085] b) adding said solution from step a) to a titanium component, and

[0086] c) obtaining said solid catalyst component particles,

[0087] and adding a non-phthalic internal electron donor (ID) prior to step c).

[0088] Preferably, the internal donor (ID) or a precursor thereof is added to the solution of step a).

[0089] According to the above procedure, the Ziegler-Natta type catalyst (ZN-C) can be obtained by a precipitation method or by an emulsion (liquid / liquid two-phase system)-solidification method, depending on the physical conditions, especially the temperature used in steps b) and c).

[0090] In both methods (precipitation method or emulsion-solidification method), the catalyst chemistry is the same.

[0091] In the precipitation method, the combining of the solution of step a) with the at least one transition metal compound (TC) in step b) is performed and the whole reaction mixture is kept at a temperature of at least 50°C, more preferably in the range of 55 to 110°C, more preferably in the range of 70 to 100°C, to ensure complete precipitation of the catalyst components in the form of solid particles (step c).

[0092] In the emulsion-solidification method, in step b), the solution of step a) is added to the at least one transition metal compound (TC) usually at a lower temperature, such as -10 to below 50°C, preferably -5 to 30°C. During stirring of the emulsion, the temperature is usually kept at -10 to below 40°C, preferably -5 to 30°C. The droplets of the dispersed phase of the emulsion form the active catalyst ingredient. The solidification of the droplets (step c) is suitably performed by heating the emulsion to 70 to 150°C, preferably 80 to 110°C.

[0093] The catalyst prepared according to the present application is preferably prepared using the emulsion-solidification method.

[0094] In a preferred embodiment, a solution of a2) or a3) is used in step a), i.e. a solution of (Ax) or a mixture of (Ax) and (Bx).

[0095] The alkoxymagnesium compounds (Ax), (Ax) and (Bx) can be prepared in situ in the first step of the catalyst preparation process (step a)) by reaction of a magnesium compound with one or more alcohols as described above, or the alkoxymagnesium compounds can be separately prepared alkoxymagnesium compounds, or they can even be commercially available as ready-made alkoxymagnesium compounds and used as such in the catalyst preparation process according to the present application.

[0096] Illustrative examples of alcohol (A) are monoethers of diols (diol monoethers). Preferred alcohols (A) are C2to C4diol monoethers, wherein the ether moiety comprises 2 to 18 carbon atoms, preferably 4 to 12 carbon atoms. Preferred examples are 2-(2- ethylhexyloxy)ethanol, 2-butyloxyethanol, 2-hexyloxyethanol and 1,3-propanediol- monobutyl ether, 3-butyloxy-2-propanol, with 2-(2-ethylhexyloxy)ethanol and 1,3- propanediol-monobutyl ether, 3-butyloxy-2-propanol being particularly preferred.

[0097] Illustrative monohydric alcohols (B) have the formula ROH, wherein R is a linear or branched C6-C 10 alkyl residue. Most preferred monohydric alcohols are 2-ethyl-1-hexanol or octanol.

[0098] It is preferred to use mixtures of alkoxymagnesium compounds (Ax) and (Bx) or mixtures of alcohols (A) and (B), respectively, with a molar ratio of Bx:Ax or B:A employed of 8:1 to 2:1, more preferably of 5:1 to 3:1.

[0099] The alkoxymagnesium compound can be a reaction product of one or more alcohols as defined above and a magnesium compound selected from the group consisting of dialkylmagnesium, alkylalkoxymagnesium, dialkoxymagnesium, halogenated alkoxymagnesium and halogenated alkylmagnesium. The alkyl groups can be similar or different C1-C 20 alkyl, preferably C2-C 10 alkyl. Typical alkyl-alkoxymagnesium compounds, when used, are ethyl butoxymagnesium, butyl pentoxy magnesium, octyl butoxymagnesium and octyl octoxymagnesium. Preferably, a dialkylmagnesium is used. Most preferred dialkylmagnesium is butyl octyl magnesium or butyl ethyl magnesium.

[0100] It is also possible that the magnesium compound, in addition to being reacted with alcohol (A) and alcohol (B), can also be reacted with a polyol (C) of the formula R"(OH) m , wherein R" is a linear, cyclic or branched C2to C 10 hydrocarbon residue and m is an integer from 2 to 6.

[0101] Thus, the alkoxymagnesium compound of step a) is selected from the group consisting of dialkoxymagnesium, diaryloxymagnesium, halogenated alkoxymagnesium, halogenated aryloxymagnesium, alkylalkoxymagnesium, arylalkoxymagnesium and alkylaryloxymagnesium. In addition, mixtures of dihalogenmagnesium and dialkoxymagnesium can be used.

[0102] The solvent employed for the preparation of the present catalyst can be selected from aromatic and aliphatic straight chain, branched and cyclic hydrocarbons having 5 to 20 carbon atoms, more preferably 5 to 12 carbon atoms, or mixtures thereof. Suitable solvents include benzene, toluene, cumene, xylene, pentane, hexane, heptane, octane and nonane. Hexane and pentane are particularly preferred.

[0103] The magnesium compound is typically provided as a 10 to 50 wt% solution in the above solvent. A typical commercially available magnesium compound, in particular a dialkyl magnesium solution is a 20 to 40 wt% solution in toluene or heptane.

[0104] The reaction for the preparation of the magnesium alkoxide compound can be carried out at a temperature of 40 °C to 70 °C. The most suitable temperature is selected depending on the magnesium compound and the alcohol(s) used.

[0105] Most preferably, the titanium component is a titanium halide, such as TiCI4.

[0106] The internal donor (ID) used for the preparation of the catalyst of the present application is preferably a (di)ester of a non-phthalic (di)acid, more preferably a diester of a mono-unsaturated dicarboxylic acid, such as a maleate, a citraconate or a cyclohexene-1,2-dicarboxylate, most preferably a citraconate.

[0107] In the emulsion process, the two-phase liquid-liquid system can be formed by simple agitation and optionally the addition of (further) solvents and additives, such as a turbulence minimizer (TMA) and / or an emulsifier and / or an emulsion stabilizer, like a surfactant, which are used in a manner known in the art for promoting the formation and / or stabilizing the emulsion. Preferably, the surfactant is an acrylic or methacrylic acid polymer. Particularly preferred is a C 12 to C 20 The (meth)acrylate, such as poly(methylacrylate) (hexadecyl) and poly(methylacrylate) (octadecyl) and mixtures thereof. If used, the turbulence minimizer (TMA) is preferably selected from an alpha-olefin polymer of an alpha-olefin monomer having 6 to 20 carbon atoms, like a polyoctene, polynonene, polydecene, polyundecene or polydodecene or mixtures thereof. Most preferred is a polydecene.

[0108] The solid particulate product obtained by the precipitation or emulsion-solidification process can be washed at least once, preferably at least twice, most preferably at least three times with an aromatic and / or aliphatic hydrocarbon, preferably with toluene, heptane or pentane. The catalyst can be further dried, like by evaporation or flushing with nitrogen, or it can be slurried into an oily liquid without any drying step.

[0109] The Ziegler-Natta catalyst finally obtained is desirably in the form of particles, generally having an average particle size ranging from 5 to 200 μm, preferably from 10 to 100 μm. The particles are compact, have a low porosity and a surface area lower than 20 g / m2 2 , more preferably lower than 10 g / m 2 . Typically, the amount of Ti in the catalyst composition is from 1 to 6% by weight, the amount of Mg is from 10 to 20% by weight and the amount of donor is from 10 to 40% by weight.

[0110] The detailed description of the preparation of the catalyst is disclosed in WO 2012 / 007430, EP 2 415 790, EP 2 610 270, EP 2610 271 and EP 2 610 272, which are incorporated herein by reference.

[0111] The prepolymerization of the Ziegler-Natta catalyst with the monomer (I) is carried out in the presence of an alkyl aluminium cocatalyst and of an external donor (ED).

[0112] Suitable external donors (ED) include certain silanes, ethers, esters, amines, ketones, heterocyclic compounds and blends of these compounds. It is especially preferred to use silanes. Most preferably, silanes having the following general formula are used:

[0113] R a p R b q Si(OR c ) (4-p-q)

[0114] wherein R a , R b and R c represent a hydrocarbon group, in particular an alkyl group or a cycloalkyl group, and wherein p and q are numbers ranging from 0 to 3, the sum p+q being equal to or lower than 3. R a , R b and R c can be chosen independently from each other and can be the same or different. Specific examples of such silanes are (tert-butyl)2Si(OCH3)2, (cyclohexyl)(methyl)Si(OCH3) 2 , (phenyl)2Si(OCH3)2and (cyclopentyl)2Si(OCH3)2, or having the following general formula

[0115] Si(OCH2CH3)3(NR 3 R 4 )

[0116] wherein R 3 and R 4 can be the same or different and represent a hydrocarbon group having from 1 to 12 carbon atoms.

[0117] R 3 and R 4 are independently selected from the group consisting of linear aliphatic hydrocarbon groups having 1 to 12 carbon atoms, branched aliphatic hydrocarbon groups having 1 to 12 carbon atoms and cyclic aliphatic hydrocarbon groups having 1 to 12 carbon atoms. It is particularly preferred that R 3 and R 4 are independently selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decyl, iso-propyl, iso-butyl, iso-pentyl, tert-butyl, tert-pentyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

[0118] More preferably, R 1 and R 2 are both identical, still more preferably R 3 and R 4 are both ethyl.

[0119] Especially preferred external donors (ED) are pentyl dimethoxysilane donors (D-donor) or cyclohexyl methyl dimethoxysilane donors (C-donor), the latter being especially preferred.

[0120] In addition to the Ziegler-Natta catalyst (ZN-C) and the external donor (ED), a co-catalyst is used in the prepolymerization step a). The co-catalyst is an aluminum compound, preferably an alkyl aluminum, an aluminum halide or an alkyl aluminum halide compound. Thus, in a particular embodiment, the co-catalyst (Co) is a trialkyl aluminum, such as triethyl aluminum (TEAL), a dialkyl aluminum chloride or an alkyl aluminum dichloride or mixtures thereof. In a particular embodiment, the co-catalyst (Co) is triethyl aluminum (TEAL).

[0121] Advantageously, the triethyl aluminum (TEAL) has a hydride content of less than 1.0 wt.-%, expressed as AIH3, relative to the triethyl aluminum (TEAL). More preferably, the hydride content is less than 0.5 wt.-%, most preferably the hydride content is less than 0.1 wt.-%.

[0122] Preferably, the ratio [Co / ED] between the co-catalyst (Co) and the external donor (ED) and / or the ratio [Co / TC] between the co-catalyst (Co) and the titanium component (TC) should be carefully selected.

[0123] Thus,

[0124] (a) the molar ratio [Co / ED] of the co-catalyst (Co) to the external donor (ED) is preferably in the range of 5 to 45, preferably in the range of 5 to 35, more preferably in the range of 5 to 25; and optionally

[0125] (b) the molar ratio [Co / TC] of the cocatalyst (Co) to the titanium component (TC) is preferably in the range of 80 and above to 500, preferably in the range of 100 to 450, still more preferably in the range of 120 to 350.

[0126] As mentioned above, the Ziegler-Natta catalyst (ZN-C) is pre-polymerized with a monomer (I) having the general formula

[0127] CH2=CH-CHR 1 R 2 (I)

[0128] wherein R 1 and R 2 are individual alkyl groups having one or more carbon atoms, or form an optionally substituted saturated, unsaturated or aromatic ring or fused ring system, which contains 4 to 20 carbon atoms.

[0129] In a preferred embodiment, the monomer (I) is selected from the group consisting of vinylcyclohexane, vinylcyclopentane and 4-methylpent-1 -ene.

[0130] A particularly preferred embodiment of the catalyst modification comprises the following steps:

[0131] - introducing a Ziegler-Natta catalyst (ZN-C) as described above into a reaction medium,

[0132] - adding a cocatalyst (Co) and an external donor (ED),

[0133] - feeding the monomer (I) to the stirred reaction medium in a weight ratio of monomer (I) / catalyst of 0.33 to 20, preferably 0.33 to 10,

[0134] - polymerizing the vinyl compound in the presence of the Ziegler-Natta catalyst (ZN-C), the cocatalyst (Co) and the external donor (ED) at a temperature of 35 to 65 °C, and

[0135] - continuing the polymerization until a maximum concentration of less than 2000, preferably less than 1000 ppm by weight of unreacted monomer (I) is obtained,

[0136] - yielding a modified Ziegler-Natta catalyst system containing up to 20 grams of vinyl compound per 1 gram of solid catalyst.

[0137] The modified Ziegler-Natta catalyst system (II) comprises 25 to 95 % by weight of isotactic polymer based on monomer (I), more preferably 50 to 90 % by weight of isotactic polymer based on monomer (I), most preferably 60 to 80 % by weight of isotactic polymer based on monomer (I).

[0138] The modification of the Ziegler-Natta procatalyst is essentially performed prior to any contact with the metallocene catalyst system, thus prior to any prepolymerization of the catalyst mixture with the olefin monomer, i.e. propylene.

[0139] Prepolymerization here refers to a conventional, typically continuous process step performed prior to one or more main polymerization steps, in which the catalyst, in the case of the present invention the catalyst mixture, is polymerized with propylene to a minimum degree of 10 g, preferably at least 100 g, more preferably at least 500 g of polypropylene per 1 g of catalyst mixture.

[0140] By modifying the Ziegler-Natta catalyst essentially prior to its contact with the metallocene catalyst system and prior to the contact of the mixture with propylene, it can be ensured that the polymerization of the vinyl compounds is completed under the observed reaction conditions.

[0141] With regard to the modification of the catalyst, with regard to the reaction conditions involved in the modification of the catalyst and with regard to the polymerization reaction, reference is made to the international applications WO 99 / 24478, WO 99 / 24479, in particular WO 00 / 68315, which are incorporated herein by reference.

[0142] This process is also referred to as Borealis Nucleation Technology (BNT).

[0143] Due to this advantageous way of modifying the Ziegler-Natta catalyst, the subsequent polymerization steps can be performed without adding any additional external donor and additional co-catalyst to the prepolymerization step and any subsequent polymerization steps, such as bulk polymerization and / or gas phase polymerization. Only the amount of external donor and co-catalyst used during the catalyst preparation of the nucleated Ziegler-Natta catalyst is used.

[0144] Metallocene catalyst (III)

[0145] The metallocene catalyst according to the present invention can be any supported metallocene catalyst suitable for the production of isotactic polypropylene.

[0146] It is preferred that the metallocene catalyst (III) comprises a metallocene complex, a co-catalyst system comprising a boron containing co-catalyst and / or an aluminoxane co-catalyst and a silica support.

[0147] In particular, it is preferred that the metallocene catalyst (III) comprises

[0148] (i) a metallocene complex having the general formula (VI)

[0149]

[0150] wherein each X is independently a sigma-donor ligand,

[0151] L is a divalent bridge selected from -R'2C-, -R'2C-CR'2-, -R'2Si-, -R'2Si-SiR'2-, -R'2Ge-, wherein each R' is independently a hydrogen atom or a Ci-C6-hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 of the periodic table of elements, 20 - a hydrocarbyl group or a fluorine atom, or optionally two R' groups together can form a ring,

[0152] each R 1 is independently the same or can be different and is a hydrogen, a linear or branched Ci-C6-alkyl group, a C 7-20 - aralkyl, C 7-20 - alkylaryl or C 6-20 - aryl or OY group, wherein Y is a C 1-10 - hydrocarbyl group, and optionally two adjacent R 1 groups can be part of a ring comprising the phenyl carbon to which they are bonded,

[0153] each R 2 is independently the same or can be different and is a CH2-R 8 group, wherein R 8 is H or a linear or branched C 1-6 - alkyl group, a C 3-8 - cycloalkyl group, a C 6-10 - aryl group,

[0154] R 3 is a linear or branched Ci-C6-alkyl group, a C 7-20 - aralkyl group, a C 7-20 - alkylaryl group or a C6-C 20 - aryl group,

[0155] R 4 is a C(R 9 )3 group, wherein R 9 is a linear or branched Ci-C6-alkyl group,

[0156] R 5 is a hydrogen or an aliphatic Ci-C 20 - hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 of the periodic table of elements;

[0157] R 6 is a hydrogen or an aliphatic Ci-C 20 - hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 of the periodic table of elements; or

[0158] R 5 and R 6 together form a 5-membered saturated carbocyclic ring, which is optionally substituted with n groups R 10 , n being from 0 to 4;

[0159] each R 10 are identical or different and can be Ci-C 20 -hydrocarbyl, or Ci-C 20 -hydrocarbyl;

[0160] R 7 is H or linear or branched Ci-C6-alkyl or an aryl or heteroaryl group having from 6 to 20 carbon atoms, optionally substituted with 1 to 3 groups R 11 , n being from 0 to 4;

[0161] each R 11 are independently identical or can be different and are hydrogen, linear or branched Ci-C6-alkyl, C 7-20 -arylalkyl, C 7-20 -alkylaryl or C 6-20 -aryl or OY group, wherein Y is C 1-10 -hydrocarbyl,

[0162] (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and

[0163] (iii) a silica support.

[0164] The term "sigma-donor ligand" is well known to the person skilled in the art, i.e. a group which binds to the metal via a sigma bond. Thus, the anionic ligands "X" can independently be halogen or selected from the group consisting of R', OR', SiR'3, OSiR'3, OSO2CF3, OCOR', SR', NR'2 or PR'2 groups, wherein R' is independently hydrogen, linear or branched, cyclic or acyclic Ci to C 20 alkyl, C2 to C 20 alkenyl, C2 to C 20 alkynyl, C3 to C 12 cycloalkyl, C6 to C 20 aryl, C7 to C 20 aralkyl, C7 to C 20 alkaryl, C8 to C 20 aralkenyl, wherein the R' groups can optionally contain one or more heteroatoms belonging to groups 14 to 16. In a preferred embodiment, the anionic ligands "X" are identical and are either halogen, such as Cl, or methyl or benzyl groups.

[0165] A preferred monovalent anionic ligand is halogen, in particular chlorine (Cl).

[0166] More preferably, the metallocene catalyst has the formula (Via)

[0167]

[0168] wherein each R 1 are independently the same or can be different and are hydrogen or linear or branched C1-C6 alkyl, whereby each phenyl group has at least one R 1 is not hydrogen,

[0169] R' is C1-C 10 hydrocarbyl, preferably C1-C4 hydrocarbyl, more preferably methyl, and

[0170] X is independently a hydrogen atom, a halogen atom, a C1-C6 alkoxyl group, a C1-C6 alkyl group, a phenyl group or a benzyl group.

[0171] Most preferably, X is chlorine, benzyl or methyl. Preferably, the two X groups are the same. The most preferred options are two chlorides, two methyls or two benzyls, especially two chlorides.

[0172] Preferred complexes of the metallocene catalyst include:

[0173] rac-dimethylsilanediyl bis[2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert- butylinden-1-yl]zirconium dichloride,

[0174] rac-trans-dimethylsilanediyl [2-methyl-4-(4'-tert-butylphenyl)-inden-1-yl] [2-methyl-4- phenyl-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride,

[0175] rac-trans-dimethylsilanediyl [2-methyl-4-(4'-tert-butylphenyl)-inden-1-yl] [2-methyl-4- phenyl-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride,

[0176] rac-trans-dimethylsilanediyl [2-methyl-4-(3',5'-tert-butylphenyl)-1,5,6,7-tetrahydro- sym-isoindol-1-yl] [2-methyl-4-(3',5'-dimethyl-phenyl)-5-methoxy-6-tert-butylinden-1- yl] zirconium dichloride,

[0177] rac-trans-dimethylsilanediyl [2-methyl-4-(3',5'-tert-butylphenyl)-1,5,6,7-tetrahydro- sym-isoindol-1-yl] [2-methyl-4-(3',5'-dimethyl-phenyl)-5-methoxy-6-tert-butylinden-1- yl] zirconium dichloride,

[0178] Racemic-trans-dimethylsilanediyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-symmetric-indarsen-1-yl][2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride,

[0179] Racemic-trans-dimethylsilanediyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-symmetric-indarsen-1-yl][2-methyl-4-(3',5-5-di-tert-butyl-phenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride.

[0180] Particularly preferred is racemic-trans-dimethylsilanediyl[2-methyl-4,8-bis-(3',5'-dimethylphenyl)-1,5,6,7-tetrahydro-symmetric indarsen-1-yl][2-methyl-4-(3',5'-dimethylphenyl)-5-methoxy-6-tert-butylindene-1-yl]zirconium dichloride (VIb).

[0181]

[0182] The ligands required to form the complexes of the present invention and thus the catalysts of the present invention can be synthesized by any method, and skilled organic chemists are capable of designing various synthetic schemes to produce the necessary ligand materials. For example, WO2007 / 116034 discloses the necessary chemistry. Synthetic schemes can also generally be found in WO 2002 / 02576, WO 2011 / 135004, WO 2012 / 084961, WO 2012 / 001052, WO 2011 / 076780, WO 2015 / 158790 and WO 2018 / 122134. Particular reference is made to WO 2019 / 179959, which describes the most preferred catalyst of the present invention.

[0183] According to the present invention, a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst is used in combination with a metallocene catalyst complex as defined above.

[0184] Aluminoxane co-catalysts can be a type of catalyst having formula (VII):

[0185]

[0186] Where n is typically between 6 and 20, and R has the following meanings.

[0187] Aluminoxanes are formed during the partial hydrolysis of organoaluminum compounds, such as those having the formulas AlR3, AlR2Y, and Al2R3Y3, where R can be, for example, C1-C2. 10 Alkyl groups, preferably C1-C5 alkyl groups, or C 3-10 cycloalkyl, C7-C 12 Aryl or alkylaryl and / or phenyl or naphthyl, wherein Y can be hydrogen, halogen, preferably chlorine or bromine, or C1-C 10 Alkoxy, preferably methoxy or ethoxy. The resulting oxyaluminoxane is usually not a pure compound, but a mixture of oligomers of formula (III).

[0188] The preferred aluminoxane is methylaluminoxane (MAO). Since the aluminoxanes used as cocatalysts according to the present invention are prepared by means of their own process rather than as pure compounds, the molar concentrations of the aluminoxane solutions mentioned below are based on their aluminum content.

[0189] According to the present invention, a boron-containing cocatalyst can be used instead of an aluminum oxane cocatalyst, or an aluminum oxane cocatalyst can be used in combination with a boron-containing cocatalyst.

[0190] Those skilled in the art will understand that, when using a boron-based cocatalyst, the complex is typically pre-alkylated by reacting it with an alkylaluminum compound (such as TIBA). This procedure is well known, and any suitable alkylaluminum can be used, such as Al(C1-C6 alkyl)3. Preferred alkylaluminum compounds are triethylaluminum, triisobutylaluminum, triisohexylaluminum, tri-n-octylaluminum, and tri-isooctylaluminum.

[0191] Alternatively, when using a borate cocatalyst, the metallocene catalyst complex is in its alkylated form, i.e., a dimethyl or dibenzyl metallocene catalyst complex can be used, for example.

[0192] Boron-based cocatalysts of interest include those of formula (VIII).

[0193] BY3(VIII)

[0194] wherein Y is the same or different and is a hydrogen atom, an alkyl group having from 1 to about 20 carbon atoms, an aryl group having from 6 to about 15 carbon atoms, an alkylaryl group, an arylalkyl group, a haloalkyl group or a haloaryl group, wherein each group has from 1 to 10 carbon atoms in the alkyl group and from 6 to 20 carbon atoms in the aryl group or each group has fluorine, chlorine, bromine or iodine. Preferred embodiments of Y are methyl, propyl, isopropyl, isobutyl or trifluoromethyl, unsaturated groups such as aryl or haloaryl groups, such as phenyl, tolyl, benzyl, p-fluorophenyl, 3,5-difluorophenyl, pentachlorophenyl, pentafluorophenyl, 3,4,5-trifluorophenyl and 3,5-di(trifluoromethyl)phenyl. Preferred options are trisfluoroborane, trisphenylborane, tris(4-fluorophenyl)borane, tris(3,5-difluorophenyl)borane, tris(4-fluoromethylphenyl)borane, tris(2,4,6-trifluorophenyl)borane, tris(pentafluorophenyl)borane, tris(tolyl)borane, tris(3,5-dimethyl-phenyl)borane, tris(3,5-difluorophenyl)borane and / or tris(3,4,5-trifluorophenyl)borane.

[0195] Particularly preferred is tris(pentafluorophenyl)borane.

[0196] However, it is preferred that a borate salt, i.e. a compound containing borate 3+ions, is used. Such ionic co-catalysts preferably contain a non-coordinating anion such as tetra(pentafluorophenyl)borate and tetraphenylborate. Suitable counterions are protonated amines or aniline derivatives such as methylammonium, anilinium, dimethylammonium, diethylammonium, N-methylanilinium, diphenylammonium, N,N-dimethylanilinium, trimethylammonium, triethylammonium, tri-n-butylammonium, methyldiphenylammonium, pyridinium, p-bromo-N,N-dimethylanilinium or p-nitro-N,N-dimethylanilinium.

[0197] Preferred ionic compounds which can be used according to the present application include:

[0198] triethylammonium tetra(phenyl)borate,

[0199] tributylammonium tetra(phenyl)borate,

[0200] trimethylammonium tetra(tolyl)borate,

[0201] tributylammonium tetra(tolyl)borate,

[0202] tributylammonium tetra(pentafluorophenyl)borate,

[0203] tripropylammonium tetra(dimethylphenyl)borate,

[0204] tributylammonium tetra(trifluoromethylphenyl)borate,

[0205] tributylammonium tetra(4-fluorophenyl)borate,

[0206] N,N-dimethylcyclohexylammonium tetra(pentafluorophenyl)borate,

[0207] N,N-dimethylbenzylammonium tetra(pentafluorophenyl)borate,

[0208] N,N-dimethylphenylammonium tetra(phenyl)borate,

[0209] N,N-diethylphenylammonium tetra(phenyl)borate,

[0210] N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate,

[0211] N,N-di(propyl)ammonium tetra(pentafluorophenyl)borate,

[0212] di(cyclohexyl)ammonium tetra(pentafluorophenyl)borate,

[0213] triphenylphosphonium tetra(phenyl)borate,

[0214] triethylphosphonium tetra(phenyl)borate,

[0215] diphenylphosphonium tetra(phenyl)borate,

[0216] tri(methylphenyl)phosphonium tetra(phenyl)borate,

[0217] tri(dimethylphenyl)phosphonium tetra(phenyl)borate,

[0218] triphenylcarbenium tetrakis(pentafluorophenyl)borate, or

[0219] ferrocenium tetrakis(pentafluorophenyl)borate.

[0220] triphenylcarbenium tetrakis(pentafluorophenyl)borate,

[0221] N,N-dimethylcyclohexylammonium tetra(pentafluorophenyl)borate, or

[0222] N,N-dimethylbenzylammonium tetra(pentafluorophenyl)borate.

[0223] Surprisingly, certain boron co-catalysts were found to be especially preferred. Thus, preferred borate salts for use in the present application include the triphenylmethyl ion. Thus, the use of N,N-dimethylammonium-tetra-pentafluorophenylborate and Ph3CB(PhF5)4 and analogs thereof is especially preferred.

[0224] According to the present invention, the preferred cocatalyst is an aluminum oxane, more preferably a methyl aluminum oxane, a combination of an aluminum oxane with an alkyl aluminum, boron or borate cocatalyst, and a combination of an aluminum oxane with a boron-based cocatalyst.

[0225] The appropriate amount of co-catalyst is well known to those skilled in the art.

[0226] The molar ratio of boron to metallocene ions can be in the range of 0.5:1 to 10:1 mol / mol, preferably in the range of 1:1 to 10:1, and especially in the range of 1:1 to 5:1 mol / mol.

[0227] The molar ratio of Al to metal ions in aluminoxane can be in the range of 1:1 to 2000:1 mol / mol, preferably in the range of 10:1 to 1000:1, and more preferably in the range of 50:1 to 500:1 mol / mol.

[0228] The catalyst can be used in supported or unsupported form, preferably in supported form. The particulate support material used is preferably an organic or inorganic material, such as silica, alumina, or zirconium oxide, or a mixed oxide, such as silica-alumina, particularly silica, alumina, or silica-alumina. Silica support is preferred. Those skilled in the art know the procedures required for supporting metallocene catalysts.

[0229] Particularly preferred is that the support is a porous material so that the complex can be loaded into the pores of the support, for example using methods similar to those described in WO94 / 14856 (Mobil), WO95 / 12622 (Borealis) and WO2006 / 097497.

[0230] The average particle size of the silica support can typically be 10 to 100 μm. However, it has been shown that if the support has an average particle size d50 of 15 to 80 μm, preferably 18 to 50 μm, it can yield particular advantages.

[0231] The average pore size of the silica support can be in the range of 10 to 100 nm, and the pore volume is 1 to 3 mL / g.

[0232] Examples of suitable support materials include, for example, ES757 manufactured and sold by PQ, Sylopol 948 manufactured and sold by Grace, or SUNSPERA DM-L-303 silica manufactured by AGC Si-Tech. The support may optionally be calcined prior to its use in catalyst preparation to achieve optimal silanol group content.

[0233] The use of these loads is common practice in the field.

[0234] Catalyst blend (IV)

[0235] The catalyst blend (IV) of the present application is a blend of the catalyst composition (II) and the supported metallocene catalyst (III). Therefore, all preferred embodiments of these components as described in detail in the previous section apply mutatis mutandis to the catalyst blend (IV).

[0236] The weight ratio of the catalyst composition (II) and the supported metallocene catalyst (III) in the catalyst blend (IV) is in the range of 1 :99 to 55:45, more preferably in the range of 5:95 to 50:50, still more preferably in the range of 5:95 to 40:60, even more preferably in the range of 10:90 to 40:60, most preferably in the range of 20:80 to 35:65.

[0237] It is preferred that the catalyst blend (IV) does not contain other components having catalytic activity for the polymerization of propylene in addition to the catalyst composition (II) and the supported metallocene catalyst (III) as described above.

[0238] In one embodiment, the catalyst blend (IV) consists of the catalyst composition (II) and the supported metallocene catalyst (III). The skilled person will understand that the structure "consists of" in the context of the catalyst blend (IV) does not exclude the presence of waxes and oils which are typically added to catalyst compositions for storage and transport, and to facilitate their addition to continuous polymerization processes.

[0239] Therefore, it is preferred that the catalyst blend (IV) comprises 1 to 55 wt.-% of the catalyst composition (II) relative to the total weight of the catalyst blend (IV) and 45 to 99 wt.-% of the supported metallocene catalyst (III) relative to the total weight of the catalyst blend (IV).

[0240] More preferably, the catalyst blend (IV) comprises 5 to 50 wt.-% of the catalyst composition (II) relative to the total weight of the catalyst blend (IV) and 50 to 95 wt.-% of the supported metallocene catalyst (III) relative to the total weight of the catalyst blend (IV).

[0241] Still more preferably, the catalyst blend (IV) comprises 5 to 40 wt.-% of the catalyst composition (II) relative to the total weight of the catalyst blend (IV) and 60 to 95 wt.-% of the supported metallocene catalyst (III) relative to the total weight of the catalyst blend (IV).

[0242] Even more preferably, the catalyst blend (IV) comprises from 10 to 40 wt.-% of the catalyst composition (II) and from 60 to 90 wt.-% of the supported metallocene catalyst (III) with respect to the total weight of the catalyst blend (IV).

[0243] Most preferably, the catalyst blend (IV) comprises from 20 to 35 wt.-% of the catalyst composition (II) and from 65 to 80 wt.-% of the supported metallocene catalyst (III) with respect to the total weight of the catalyst blend (IV).

[0244] The person skilled in the art will understand that when calculating the amount of catalyst composition (II) and supported metallocene catalyst (III) present in the catalyst blend (IV), any amount of non-catalytic diluent, in particular waxes and oils, should be neglected for this calculation purpose.

[0245] Process

[0246] The present invention relates to a process for the preparation of isotactic polypropylene compositions comprising the following steps:

[0247] (a) prepolymerizing a Ziegler-Natta type catalyst comprising a magnesium halide support, a titanium component and an internal donor (ID) with a monomer (I) having the general formula (I) in the presence of an aluminum alkyl cocatalyst and an external donor (ED) to obtain a catalyst composition (II), wherein the internal donor is not a phthalate and the Ziegler-Natta type catalyst is free of phthalates

[0248] CH2=CH-CHR 1 R 2 (I)

[0249] wherein R 1 and R 2 are individual alkyl groups having one or more carbon atoms or form an optionally substituted saturated, unsaturated or aromatic ring or fused ring system containing 4 to 20 carbon atoms, the catalyst composition (II) comprising from 25 to 95 wt.-% of isotactic polymer based on the monomer (I);

[0250] (b) mixing the catalyst composition (II) with a supported metallocene catalyst (III) suitable for the production of isotactic polypropylene in a weight ratio (II):(III) of 1 :99 to 55:45 in an inert medium to obtain a catalyst blend (IV);

[0251] (c) using the catalyst blend (IV) in one or more reaction steps for the polymerization of propylene and optionally one or more comonomers selected from ethylene and a-olefins containing 4 to 12 carbon atoms to obtain an isotactic propylene homo- or copolymer (V);

[0252] (d) melt blending the isotactic propylene homo- or copolymer (V) with additives as antioxidants and acid scavengers and optionally nucleating agents, followed by pelletization.

[0253] Step c) can be a one- or multi-stage polymerization process for the preparation of the isotactic propylene polymer composition.

[0254] Any propylene polymerization process known for the polymerization of propylene and optionally comonomers in combination with the catalyst mixture as described above can be used, for example gas phase, bulk or slurry phase, solution polymerization or any combination thereof.

[0255] The polymerization can be a one-stage or a two-stage or a multi-stage polymerization process in at least one polymerization reactor. For a two-stage or multi-stage process different combinations can be used, for example gas-gas phase, slurry-slurry phase, slurry-gas phase process; slurry-gas phase polymerization is the preferred process. Any type of polymerization as listed above is possible, however, a slurry process is a preferred process for a one-stage process.

[0256] In addition to the actual polymerization, the process configuration can include any pre- or post-reactors.

[0257] Preferably, the first step for the production of the polypropylene composition according to the present application is a prepolymerization step.

[0258] The prepolymerization can be carried out in any type of continuously operated polymerization reactor. Suitable reactors are continuously stirred tank reactors (CSTR), loop reactors or divided reactors as disclosed in WO 97 / 33920 or WO 00 / 21656 or a cascade of two or more reactors can be used.

[0259] Although the prepolymerization can be carried out as slurry polymerization or gas phase polymerization, it is preferred that the prepolymerization is carried out in the form of a slurry polymerization in liquid propylene, more preferably in a loop prepolymerization reactor.

[0260] In a preferred embodiment, the prepolymerization is carried out as bulk slurry polymerization in liquid propylene, i.e. the liquid phase mainly comprises propylene with a small amount of other reactants and optionally inert components dissolved.

[0261] The prepolymerization is carried out in a continuously operated reactor with an average residence time of 5 minutes to 90 minutes. Preferably, the average residence time is in the range of 10 to 60 minutes, more preferably in the range of 15 to 45 minutes.

[0262] The prepolymerization reaction is generally carried out at a temperature of 0 to 50 °C, preferably 10 to 45 °C, more preferably 15 to 35 °C.

[0263] The pressure in the prepolymerization reactor is not critical, but must be high enough to keep the reaction mixture in the liquid phase, and is generally chosen so that the pressure is higher than or equal to the pressure in the subsequent polymerization. Thus, the pressure can be 20 to 100 bars, for example 30 to 70 bars.

[0264] In case a prepolymerization step is carried out, the whole of the catalyst blend is introduced in the prepolymerization step.

[0265] Other components can also be added in the prepolymerization stage. Thus, hydrogen can be added to the prepolymerization stage to control the molecular weight of the prepolymer, as known in the art. Furthermore, antistatic additives can be used to prevent the particles from adhering to each other or to the walls of the reactor.

[0266] A small amount of comonomer (ethylene and / or C4-C 10 The amount of comonomer is less than 5 wt% to avoid the occurrence of sticky particles in the catalyst particles of the prepolymer due to a decrease in the crystallinity of the prepolymer.

[0267] The reactants, catalyst mixture, propylene, comonomer, additives, etc. can be introduced into the prepolymerization reaction or reactor continuously or intermittently. Continuous addition is preferred to improve process stability. The prepolymerized catalyst can be withdrawn from the prepolymerization reaction or reactor continuously or intermittently. Again, continuous withdrawal is preferred.

[0268] The precise control of the prepolymerization conditions and reaction parameters is within the skill of the art.

[0269] The next step of the process for producing a polypropylene composition according to the present application is preferably a slurry phase polymerization step, i.e. in the liquid phase.

[0270] The slurry polymerization is preferably a so-called bulk polymerization. By "bulk polymerization" is meant a process in which the polymerization is carried out in a liquid monomer in the substantial absence of an inert diluent. However, as known to the skilled person, the monomer used for commercial production is never pure, but always contains aliphatic hydrocarbons as impurities. For example, propylene monomer can contain up to 5% of propane as an impurity. Since propylene is consumed in the reaction and also recycled from the reaction effluent back to the polymerization, the inert components tend to accumulate, so that the reaction medium can contain up to 40 wt% of other compounds in addition to the monomer. However, it will be understood that such a polymerization process is still within the meaning of "bulk polymerization" as defined above.

[0271] The temperature in the slurry polymerization is typically from 50 to 110°C, preferably from 60 to 100°C, in particular from 65 to 95°C. The pressure is from 1 to 150 bar, preferably from 10 to 100 bar. In some cases, it can be preferred to carry out the polymerization at a temperature above the critical temperature of the fluid mixture comprising the reaction phase and at a pressure above the critical pressure of the fluid mixture. Such reaction conditions are often referred to as "supercritical conditions". The phrase "supercritical fluid" is used to indicate a fluid or fluid mixture having a temperature and pressure exceeding the critical temperature and pressure of the fluid or fluid mixture.

[0272] The slurry polymerization can be carried out in any known reactor for slurry polymerization. Such reactors include continuous stirred tank reactors and loop reactors. It is especially preferred to carry out the polymerization in a loop reactor. In such reactors, the slurry is circulated at high speed along a closed pipe by the use of a circulation pump. Loop reactors are well known in the art and examples are given in US-A-4582816, US-A-3405109, US-A-3324093, EP-A-479186 and US-A-5391654.

[0273] The residence time can vary in the reactor zones identified above. In one embodiment, the residence time in the slurry reactor (e.g. a loop reactor) is in the range from 0.5 to 5 hours, for example from 0.5 to 2 hours, while the residence time in the gas phase reactor is typically in the range from 1 to 8 hours, such as from 1.5 to 4 hours.

[0274] The slurry can be withdrawn from the reactor continuously or intermittently. A preferred way of intermittent withdrawal is to use a settling leg in which the solids concentration of the slurry is allowed to increase, after which a batch of concentrated slurry is withdrawn from the reactor. The use of settling legs is disclosed inter alia in US-A-3374211, US-A-3242150 and EP-A-1310295. Continuous withdrawal is disclosed inter alia in EP-A-891990, EP-A-1415999, EP-A-1591460 and EP-A-1860125. Continuous withdrawal can be combined with a suitable concentration method as disclosed in EP-A-1860125 and EP-A-1591460.

[0275] Other components can also be introduced into the slurry polymerization stage as known in the art. Thus, hydrogen is added to control the molecular weight of the polymer. Process additives can also be introduced into the reactor to facilitate stable operation of the process.

[0276] If the slurry polymerization stage is followed by a gas phase polymerization stage, the slurry is preferably directly introduced into the gas phase polymerization zone without a flashing step between the stages. Such a direct feed is described in EP-A-887379, EP-A-887380, EP-A-887381 and EP-A-991684.

[0277] The reaction product of the slurry phase polymerization, preferably carried out in a loop reactor, is then optionally transferred to a subsequent gas phase reactor.

[0278] Accordingly, the optional third step of the process for producing a polypropylene composition according to the present application is preferably a gas phase polymerization step.

[0279] The polymerization in the gas phase can be carried out in a fluidized bed reactor, a fast fluidized bed reactor or a settling bed reactor or any combination of these reactors. When a combination of reactors is used, the polymer is transferred from one polymerization reactor to another. Furthermore, part or all of the polymer from a polymerization stage can be returned to the preceding polymerization stage.

[0280] The gas phase reactor is typically operated at a temperature in the range of 50 to 100 °C, preferably in the range of 65 to 95 °C. The pressure is suitably in the range of 10 to 40 bar, preferably 15 to 30 bar.

[0281] If desired, the polymerization can be carried out in a known manner in supercritical conditions in slurry, preferably in a loop reactor, and / or in a gas phase reactor in condensed mode.

[0282] A preferred multi-stage process is a slurry-gas phase process, such as the process known as BORSTAR® technology developed by Borealis. In this regard, reference is made to EP 0 887 379 Al, WO 92 / 12182, WO 2004 / 000899, WO 2004 / 111095, WO 99 / 24478, WO 99 / 24479 and WO 00 / 68315, incorporated herein by reference.

[0283] A further suitable slurry-gas phase process is the LyondellBasell's PROCESS.

[0284] It is particularly preferred that the polymerization step (c) comprises a pre-polymerization step in liquid phase with propylene and optionally a small amount of ethylene at a temperature of 15 to 35 °C, followed by at least two main polymerization steps in liquid and / or gas phase at a temperature of 65 to 95 °C.

[0285] It is also preferred that the polymerization step (c) does not comprise the addition of any further external donor (ED), Ziegler-Natta co-catalyst (Co) or metallocene co-catalyst.

[0286] The melt-mixing step (d) is preferably carried out in a continuous melt-mixing device selected from the group of single-screw extruders, twin-screw extruders and co-kneaders at a temperature range of 180 to 280 °C.

[0287] Isotactic propylene polymer composition

[0288] The isotactic propylene polymer composition according to the present application, in its broadest sense, can be any propylene polymer composition of the reactor blend produced by the method described above.

[0289] All preferred embodiments of the method described above, either with respect to the method features, or with respect to the features of the catalyst blend (IV), or with respect to the individual catalyst systems (II and III), can be applied mutatis mutandis to the isotactic propylene polymer composition produced by the method.

[0290] However, it is preferred that the isotactic propylene polymer composition consists of:

[0291] (i) 45 to 99 wt.-%, relative to the total weight of the composition, of a metallocene-based homopolymer or copolymer,

[0292] (ii) 1 to 55 wt.-%, relative to the total weight of the composition, of a Ziegler-Natta based homopolymer or copolymer,

[0293] (iii) 5 to 500 ppm by weight, relative to the total weight of the composition, of a polymer nucleating agent formed in step (a), and

[0294] (iv) up to 2.0 wt.-%, relative to the total weight of the composition, of further additives such as antioxidants, acid scavengers, UV stabilizers, antistatic agents and non-polymer nucleating agents.

[0295] It is further preferred that the isotactic propylene polymer composition consists of:

[0296] (i) 50 to 95 wt.-%, relative to the total weight of the composition, of a metallocene-based homopolymer or copolymer,

[0297] (ii) 5 to 50 wt.-%, relative to the total weight of the composition, of a Ziegler-Natta based homopolymer or copolymer,

[0298] (iii) 5 to 500 ppm by weight, relative to the total weight of the composition, of a polymer nucleating agent formed in step (a), and

[0299] (iv) up to 2.0 wt.-%, relative to the total weight of the composition, of further additives such as antioxidants, acid scavengers, UV stabilizers, antistatic agents and non-polymeric nucleating agents.

[0300] It is still further preferred that the isotactic propylene polymer composition consists of:

[0301] (i) 60 to 95 wt.-%, relative to the total weight of the composition, of a metallocene-based homopolymer or copolymer,

[0302] (ii) 5 to 40 wt.-%, relative to the total weight of the composition, of a Ziegler-Natta-based homopolymer or copolymer,

[0303] (iii) 5 to 500 ppm by weight, relative to the total weight of the composition, of the polymer nucleating agent formed in step (a), and

[0304] (iv) up to 2.0 wt.-%, relative to the total weight of the composition, of further additives such as antioxidants, acid scavengers, UV stabilizers, antistatic agents and non-polymeric nucleating agents.

[0305] It is even further preferred that the isotactic propylene polymer composition consists of:

[0306] (i) 60 to 90 wt.-%, relative to the total weight of the composition, of a metallocene-based homopolymer or copolymer,

[0307] (ii) 10 to 40 wt.-%, relative to the total weight of the composition, of a Ziegler-Natta-based homopolymer or copolymer,

[0308] (iii) 5 to 500 ppm by weight, relative to the total weight of the composition, of the polymer nucleating agent formed in step (a), and

[0309] (iv) up to 2.0 wt.-%, relative to the total weight of the composition, of further additives such as antioxidants, acid scavengers, UV stabilizers, antistatic agents and non-polymeric nucleating agents.

[0310] Most preferred is that the isotactic propylene polymer composition consists of:

[0311] (i) 65 to 80 wt.-%, relative to the total weight of the composition, of a metallocene-based homopolymer or copolymer,

[0312] (ii) 20 to 35 wt.-%, relative to the total weight of the composition, of a Ziegler-Natta-based homopolymer or copolymer,

[0313] (iii) 5 to 500 ppm by weight, relative to the total weight of the composition, of the polymer nucleating agent formed in step (a), and

[0314] (iv) up to 2.0 wt.-%, relative to the total weight of the composition, of further additives like antioxidants, acid scavengers, UV stabilizers, antistatic agents and non-polymeric nucleating agents.

[0315] In each of the embodiments listed above, the combined weight of components (i) to (iv) amounts to 100 wt.-%.

[0316] The isotactic propylene polymer composition of the present application preferably has a melt flow rate MFR2, determined according to ISO 1133 at 230 °C and 2.16 kg load, in the range of 10 to 500 g / 10 min, more preferably in the range of 30 to 400 g / 10 min, most preferably in the range of 50 to 300 g / 10 min.

[0317] The isotactic propylene polymer composition of the present application preferably has a comonomer content of at most 5.0 wt.-%, more preferably at most 3.0 wt.-%, most preferably at most 2.0 wt.-%.

[0318] Preferably, the comonomer is ethylene.

[0319] Preferably, the isotactic propylene polymer composition of the present application has a content of isotactic pentad, determined by13C-NMR spectroscopy, in the range of 96.0 to 99.9 %, more preferably in the range of 97.0 to 99.0 %, most preferably in the range of 97.5 to 98.0 %. 13 Isotactic pentad content determined by13C-NMR spectroscopy <mmmm>.

[0320] Preferably, the isotactic propylene polymer composition of the present application has a 2,1 regiodefects content in the range of 0.2 to 1.2 mol%, more preferably in the range of 0.3 to 0.9 mol%, most preferably in the range of 0.4 to 0.6 mol%.

[0321] Preferably, the isotactic propylene polymer composition of the present application has a xylene cold solubles (XCS) content, determined according to ISO 16152 at 25 °C, in the range of 0.9 to 7.5 wt%, more preferably in the range of 1.0 to 6.0 wt%, most preferably in the range of 1.1 to 4.5 wt%.

[0322] Preferably, the isotactic propylene polymer composition of the present application has a melting temperature Tm in the range of 150 to 160 °C, more preferably in the range of 151 to 159 °C, most preferably in the range of 152 to 158 °C. m .

[0323] Preferably, the isotactic propylene polymer composition of the present application has a crystallization temperature Tc in the range of 120 to 132 °C, more preferably in the range of 121 to 131 °C, most preferably in the range of 122 to 130 °C. c .

[0324] Preferably, the isotactic propylene polymer composition of the present application has a difference (Tm-Tc) in the range of 15 to 35 °C, more preferably in the range of 20 to 33 °C, most preferably in the range of 25 to 31 °C. m and T c . m c .

[0325] Alternatively, the isotactic propylene polymer composition of the present application has a difference (Tm-Tc) in the range of 15 to 31 °C, more preferably in the range of 20 to 31 °C, most preferably in the range of 25 to 31 °C. m and T c . m c .

[0326] T m and T c are both determined by differential scanning calorimetry (DSC) according to ISO 11357 / part 3 / method C2 in a heat / cool / heat cycle with a scan rate of 10 °C / min in the temperature range from -30 to +225 °C.

[0327] ​​Preferably, the isotactic propylene polymer composition of the present application has a notched Charpy impact strength (NIS) measured at +23°C according to ISO 179 1 eA using 80x10x4 mm injection molded bar test specimens prepared according to EN ISO 1873-2 in the range of 1400 to 2200 MPa, more preferably in the range of 1500 to 2100 MPa, most preferably in the range of 1600 to 2000 MPa. 3 Flexural modulus determined on test bars.

[0328] Preferably, the isotactic propylene polymer composition of the present application has a notched Charpy impact strength (NIS) measured at +23°C according to ISO 179 1 eA using 80x10x4 mm injection molded bar test specimens prepared according to EN ISO 1873-2 in the range of 1400 to 2200 MPa, more preferably in the range of 1500 to 2100 MPa, most preferably in the range of 1600 to 2000 MPa. 2 Preferably, the isotactic propylene polymer composition of the present application has a notched Charpy impact strength (NIS) measured at +23°C according to ISO 179 1 eA using 80x10x4 mm injection molded bar test specimens prepared according to EN ISO 1873-2 in the range of 1400 to 2200 MPa, more preferably in the range of 1500 to 2100 MPa, most preferably in the range of 1600 to 2000 MPa. 2 Preferably, the isotactic propylene polymer composition of the present application has a notched Charpy impact strength (NIS) measured at +23°C according to ISO 179 1 eA using 80x10x4 mm injection molded bar test specimens prepared according to EN ISO 1873-2 in the range of 1400 to 2200 MPa, more preferably in the range of 1500 to 2100 MPa, most preferably in the range of 1600 to 2000 MPa. 2 Preferably, the isotactic propylene polymer composition of the present application has a notched Charpy impact strength (NIS) measured at +23°C according to ISO 179 1 eA using 80x10x4 mm injection molded bar test specimens prepared according to EN ISO 1873-2 in the range of 1400 to 2200 MPa, more preferably in the range of 1500 to 2100 MPa, most preferably in the range of 1600 to 2000 MPa. 3 Preferably, the isotactic propylene polymer composition of the present application has a notched Charpy impact strength (NIS) measured at +23°C according to ISO 179 1 eA using 80x10x4 mm injection molded bar test specimens prepared according to EN ISO 1873-2 in the range of 1400 to 2200 MPa, more preferably in the range of 1500 to 2100 MPa, most preferably in the range of 1600 to 2000 MPa.

[0329] Preferably, the isotactic propylene polymer composition of the present application has a haze value determined according to ASTM D 1003 at a thickness of 1 mm of less than 50%, more preferably of less than 35%, still more preferably of less than 25%, most preferably of equal or less than 20%. The haze value determined under these conditions is typically at least 5%.

[0330] Articles

[0331] The present application also relates to a film or molded article comprising at least 95 wt% of the isotactic propylene polymer composition as described above.

[0332] More preferably, the film or molded article comprises at least 97 wt%, even more preferably at least 99 wt% of the isotactic propylene polymer composition.

[0333] Most preferably, the film or molded article consists of the isotactic propylene polymer composition.

[0334] Preferably, the molded article is an injection molded article characterized by a haze determined according to ASTM D 1003 at a thickness of 1 mm of less than 50%, more preferably of less than 35%, still more preferably of less than 25%, most preferably of equal or less than 20%.

[0335] All preferred embodiments of the isotactic propylene polymer composition, or the process, or the catalyst blend (IV), or the individual catalyst systems (II and III), mutatis mutandis, apply to the articles of the present application.

[0336] Use

[0337] In another aspect, the present application relates to the use of a catalyst mixture for the production of isotactic propylene homo- or copolymer compositions, the catalyst mixture comprising:

[0338] (a) 45 to 95 wt.-%, relative to the total weight of the catalyst mixture, of a metallocene catalyst (III) comprising

[0339] (i) a metallocene complex having the general formula (VI)

[0340]

[0341] wherein each X is independently a sigma-donor ligand,

[0342] L is a divalent bridge selected from -R'2C-, -R'2C-CR'2-, -R'2Si-, -R'2Si-SiR'2-, -R'2Ge-, wherein each R' is independently a hydrogen atom or a C1-C 20 a hydrocarbon group or a fluorine atom, or optionally two R' groups together can form a ring,

[0343] each R 1 is independently the same or can be different and is a hydrogen, a linear or branched C1-C6-alkyl group, a C 7-20 -arylalkyl group, a C 7-20 -alkylaryl group or a C6-C 6-20 -aryl group or an OY group, wherein Y is a C 1-10 -hydrocarbon group, and optionally two adjacent R 1 groups together can be part of a ring comprising the phenyl carbon to which they are bound,

[0344] each R 2 is independently the same or can be different and is a CH2-R 8 group, wherein R 8 is H or a linear or branched C 1-6 -alkyl group, a C 3-8 -cycloalkyl group, a C 6-10 -aryl group,

[0345] R 3 is a linear or branched C1-C6-alkyl group, a C 7-20 -arylalkyl group, a C 7-20 -alkylaryl group or a C6-C 20 -aryl group,

[0346] R 4 is a C(R 9 )3 group, wherein R 9 is linear or branched C1-C6-alkyl,

[0347] R 5 is hydrogen or an aliphatic C1-C 20 -hydrocarbyl group optionally containing one or more heteroatoms belonging to group 14 of the periodic table of elements;

[0348] R 6 is hydrogen or an aliphatic C1-C 20 -hydrocarbyl group optionally containing one or more heteroatoms belonging to group 14 of the periodic table of elements;

[0349] R 5 and R 6 together can form a 5-membered saturated carbocyclic ring, which is optionally substituted with n groups R 10 , n being 0 to 4;

[0350] each R 10 is the same or different and can be a C1-C 20 -hydrocarbyl group, or a C1-C 20 -hydrocarbyl group optionally containing one or more heteroatoms belonging to group 14 of the periodic table of elements;

[0351] R 7 is H or linear or branched C1-C6-alkyl or an aryl or heteroaryl group having 6 to 20 carbon atoms, which is optionally substituted with 1 to 3 groups R 11 , n being 0 to 4;

[0352] each R 11 is independently the same or can be different and is hydrogen, linear or branched C1-C6-alkyl, C 7-20 -aralkyl, C 7-20 -alkylaryl or C 6-20 -aryl group or an OY group, wherein Y is C 1-10 -hydrocarbyl group,

[0353] (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and

[0354] (iii) a silica support, and

[0355] (b) 5 to 55 wt.-%, relative to the total weight of the catalyst mixture, of a Ziegler-Natta type catalyst composition (II) comprising

[0356] i) a Ziegler-Natta type catalyst comprising a magnesium halide support, a titanium component and an internal donor (ID), wherein the internal donor is not a phthalate and the Ziegler-Natta type catalyst does not contain a phthalate;

[0357] ii) an alkyl aluminium cocatalyst;

[0358] iii) an external donor (ED)

[0359] wherein the Ziegler-Natta catalyst composition has been modified by polymerization of monomers (I) having the general formula

[0360] CH2=CH-CHR 1 R 2 (I)

[0361] wherein R 1 and R 2 are individual alkyl groups having one or more carbon atoms, or form an optionally substituted saturated, unsaturated or aromatic ring or fused ring system containing 4 to 20 carbon atoms, such that the Ziegler-Natta type catalyst composition (II) contains 25 to 95 wt.-% of isotactic polymer based on said monomers (I)

[0362] The isotactic propylene homo- or copolymer composition has one or more, preferably all, of the following properties:

[0363] (i) a melt flow rate MFR2determined according to ISO 1133 at 230 °C and a load of 2.16 kg in the range of 5 to 500 g / 10 min,

[0364] (ii) a comonomer content of at most 6.0 wt.-%, the comonomer being preferably ethylene,

[0365] (iii) an isotactic pentad fraction as determined by13C-NMR spectroscopy in the range of 96.0 to 99.9 % 13 <mmmm>,

[0366] (iv) 2,1-zone defect content in the range of 0.2 to 1.2 mol%, and

[0367] (v) Content of xylene cold solubles (XCS) in the range of 0.9 to 9.0% by weight, determined at 25°C according to ISO 16152.

[0368] All preferred embodiments of isotactic propylene polymer compositions, methods, catalyst blends (IV), or individual catalyst systems (II and III), with necessary modifications, are applicable to the uses of this invention.

[0369] Example

[0370] 1. Definition / Measurement Method:

[0371] melt flow rate

[0372] Melt flow rate (MFR) is determined according to ISO 1133 and expressed in g / 10 min. MFR indicates the flowability of a polymer and therefore its processability. A higher melt flow rate generally indicates a lower polymer viscosity. The MFR2 for polypropylene was determined at 230°C and a load of 2.16 kg.

[0373] Differential scanning calorimetry (DSC)

[0374] Differential scanning calorimetry (DSC) analysis, melting temperature (T) m ) and enthalpy of fusion (H m ) and crystallization temperature (T) c Samples of 5 to 7 mg were measured using a TAInstrument Q200 differential scanning calorimeter (DSC). The DSC was operated according to ISO 11357 / Part 3 / Method C2 in a heating / cooling / heating cycle at a scan rate of 10 °C / min over a temperature range of -30 to +225 °C. Crystallization temperature (T c The melting temperature (T) is determined by the cooling step, while the melting temperature (T) is determined by the melting step. m ) and enthalpy of fusion (H m The result was determined by the second heating step.

[0375] Quantitative analysis of the microstructure of the PP matrix using NMR spectroscopy.

[0376] Quantitative nuclear magnetic resonance (NMR) spectroscopy was used to quantify the stereoregularity, regioregularity, and comonomer content of the polymer.

[0377] Adopt for 1 H and 13 Quantitative13C{1H}NMR spectra were recorded in solution-state on a Bruker Advance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for1H and13C respectively. All spectra were recorded at 125 °C using a13C optimised 10 mm extended temperature probehead, and nitrogen gas was used for all pneumatics.

[0378] Approximately 200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d2(TCE-d2) along with chromium(III) acetylacetonate (Cr(acac)3) to give a 65 mM solution of relaxor in solvent (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475). To ensure solution homogeneity, after initial sample preparation in the heated block, the NMR tube was further heated in a rotating oven for at least 1 hour. After insertion into the magnet, the tube was spun at 10 Hz. This setting was chosen primarily for the high resolution required for tacticity distribution quantification (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443; Busico, V.; Cipullo, R., Monaco, G., Vacatello, M., Segre, A. L., Macromolecules 30 (1997) 6251). Standard single-pulse excitation was employed using NOE and bi-level WALTZ16 decoupling (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 11289). A total of 8192 (8k) transients were acquired for each spectrum.

[0379] Quantitative13C{1H}NMR spectra were processed, integrated and relevant quantitative properties determined from integrals using proprietary computer programs. For polypropylene homopolymers, all chemical shifts were internally referenced to the methyl isotactic pentad (mmmm) at 21.85 ppm. The tacticity distribution was quantified by integration of the methyl region between 23.6 and 19.7 ppm, correcting for any sites not related to the stereosequence of interest (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443; Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A. L., Macromoleucles 30 (1997) 6251).

[0380] Specifically, the effect of regiodefects and comonomer integrations on the quantification of the tacticity distribution was corrected by subtracting representative regiodefect and comonomer integrations from the specific integral region of the stereosequence. Isotacticity was determined at the pentad level and reported as the percentage of isotactic pentad (mmmm) sequences out of all pentad sequences:

[0381] [mmmm] % = 100 * (mmmm / sum of all pentads).

[0382] The presence of 2,1 erythro regiodefects was indicated by the presence of two methyl sites at 17.7 and 17.2 ppm and confirmed by other characteristic sites.

[0383] Characteristic signals corresponding to other types of regiodefects were not observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253). The average integration of the two characteristic methyl sites at 17.7 and 17.2 ppm was used to quantify the amount of 2,1 erythro regiodefects:

[0384] P 21e = (I e6 + I e8 ) / 2.

[0385] The number of 1,2 primary inserted propylene was quantified based on the methyl region and corrected for sites contained within this region that are not related to primary insertion and primary insertion sites not contained within this region:

[0386] P 12 = I CH3 + I 12e

[0387] The total amount of propylene was quantified as the sum of primary inserted propylene and all other present regional defects:

[0388] P 总 =P 12 +P 21e

[0389] Quantify the molar percentage of defects in the 2,1 erythroline region relative to all propylene:

[0390] [21e] mole% = 100*(P) 21e / P 总 )

[0391] To determine the ethylene content, the chemical shifts of the solvent are used, with all chemical shifts indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm. This method allows for comparable references even if this structural unit is not present.

[0392] Because characteristic signals corresponding to 2,1 erythromorphic region defects were observed (as described in L. Resconi, L. Cavallo, A. Fait, F. Piemontesi, Chem. Rev. 2000, 100(4), 1253; in Cheng, HN, Macromolecules 1984, 17, 1950; and in WJ. Wang and S. Zhu, Macromolecules 2000, 33, 1157), it is necessary to correct for the effect of region defects on the performance of the measurements. No characteristic signals corresponding to other types of region defects were observed.

[0393] Using the method of Wang et al. (Wang, WJ., Zhu, S., Macromolecules 33 (2000), 1157), by... 13 C{ 1 The fraction of comonomers is quantified by integrating multiple signals across the entire spectral region of the H spectrum. This method was chosen because of its robustness and ability to indicate the presence of regional defects when needed. Slight adjustments were made to the integration region to improve applicability across the entire range of comonomer contents encountered.

[0394] For systems where only isolated ethylene is observed in the PPEPP sequence, the method of Wang et al. was modified to reduce the influence of non-zero integrals from sites that are known to be absent. This method reduces the overestimation of ethylene content in such systems and is achieved by reducing the number of sites used to determine the absolute ethylene content to the following:

[0395] E=0.5(Sββ+Sβγ+Sβδ+0.5(Sαβ+Sαγ))

[0396] By using this set of sites, the corresponding integral equation becomes:

[0397] E = 0.5(I H + I G + 0.5(I C + I D ))

[0398] The same notation as used in the article of Wang et al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157) is used. The equation for the absolute propylene content is not modified.

[0399] The mole fraction of comonomer incorporation is calculated from the mole fraction:

[0400] E [mol%] = 100 * fE

[0401] The weight fraction of comonomer incorporation is calculated from the mole fraction:

[0402] E [wt%] = 100 * (fE * 28.06) / ((fE * 28.06) + ((1 - fE) * 42.08))

[0403] The comonomer sequence distribution on the triad level is determined using the analytical method of Kakugo et al. (Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150). This method was chosen due to its robustness and slight adjustments to the integration region were made to increase the applicability to a broader range of comonomer contents.

[0404] Xylene cold soluble (XCS)

[0405] The xylene cold soluble fraction at room temperature (XCS, wt%) is determined according to ISO 16152; 5th Edition; 2005-07-01 at 25 °C.

[0406] Flexural modulus

[0407] The flexural modulus is determined according to ISO 178 at 23 °C on 80 x 10 x 4 mm 3 test bars injection moulded according to EN ISO 1873-2 in 3-point bending.

[0408] Notched impact strength (NIS)

[0409] The Charpy notched impact strength (NIS) is measured according to ISO 179 1 eA at +23 °C or -20 °C using injection moulded bar test specimens of 80 x 10 x 4 mm 3 according to EN ISO 1873-2.

[0410] Intrinsic viscosity

[0411] The intrinsic viscosity (iV) is measured according to DIN ISO 1628 / 1, October 1999, in decalin at 135 °C. For the present invention, iV, iV(SF), iV(CF) and iV(XCS) are measured directly, while iV(XCI) is calculated from iV and iV(XCS) assuming the validity of the following linear mixing rule, which is generally found to apply for chemically similar polymers:

[0412] iV = (XCS / 100%) * iV(XCS) + (XCI / 100%) * iV(XCI)

[0413] Haze

[0414] The optical properties (haze) of the polypropylene are determined on plaques of dimensions 60 x 60 x 1 mm 3 produced by injection moulding according to EN ISO 1873-2 and are measured according to ASTM D1003.

[0415] 2. Experiments:

[0416] Catalysts used:

[0417] a) Ziegler-Natta catalyst

[0418] a1 ) Ziegler-Natta catalyst containing hyper-BNT phthalate

[0419] The catalyst used as a1 ) is a transesterified Ziegler-Natta catalyst supported on magnesium chloride and prepared according to the procedure of WO 92 / 19653, which is identical to catalyst a4) of WO 2012 / 171745 A1.

[0420] In this catalyst, the internal donor is phthalate, the ratio ZN-C:VCH is 1 :5 and the external donor is di(cyclopentyl)dimethoxysilane (D-donor).

[0421] a2) Ziegler-Natta catalyst without BNT phthalate

[0422] The catalyst used as a2) is an emulsion-type Ziegler-Natta catalyst, which is identical to the catalyst used in the polymerization of the invention examples of WO 2017 / 148970 A1.

[0423] In this catalyst, the internal donor is citraconate, the ratio of ZN-C:VCH is 1 :1 and the external donor is bis(cyclopentyl)dimethoxysilane (D-donor).

[0424] a3) a Ziegler-Natta catalyst without hyper-BNT phthalate

[0425] The catalyst used as a3) is the same as for a2) except that 15.0 g of vinylcyclohexane (VCH) are added in the modification step instead of 5.0 g as for a2), resulting in a ratio of ZN-C:VCH of 1 :3.

[0426] b) metallocene catalyst

[0427] b1) comparative metallocene catalyst

[0428] The catalyst b1 is rac-methyl(cyclohexyl)silanediyl bis(2-methyl-4-(4-tert- butylphenyl)indenyl)zirconium dichloride prepared according to examples 17 to 18 of WO 2005 105863 A2. The preparation of a self-supported active catalyst is achieved as described in WO 2012 / 171745 A1 for catalyst b1).

[0429]

[0430] b2) inventive metallocene catalyst

[0431] The catalyst b2 is trans-dimethylsilanediyl[2-methyl-4,8-di(3,5-dimethylphenyl)- 1,5,6,7-tetrahydro-p-s-indacen-1-yl][2-methyl-4-(3,5-dimethylphenyl)-5-methoxy-6- tert-butylinden-1-yl]zirconium dichloride as disclosed in WO 2019 / 179959 A1 as MC-2. The supported metallocene catalyst is produced analogously to IE2 in WO 2019 / 179959 A1.

[0432]

[0433] Inventive examples IE1 to IE5 and comparative examples CE1 to CE5

[0434] Each of the inventive examples and comparative examples is prepared in a pilot plant comprising a pre-polymerization reactor, a loop reactor and a gas phase reactor connected in series. The pilot plant is operated at a temperature of 65 °C, a pressure of 50 bar and a residence time of 1.5 h.

[0435] The following catalysts / catalyst blends are used:

[0436] IE1 to IE5: 30:70 blend of catalysts a3) and b2)

[0437] CE1 : Catalyst a2)

[0438] CE2: Catalyst a3)

[0439] CE3: Catalyst b2)

[0440] CE4: 10:90 blend of catalysts a1 ) and b1 )

[0441] CE5: Catalyst b1 )

[0442] Table 1 Polymerisation conditions for inventive and comparative examples

[0443]

[0444] Table 1 (continued) Polymerisation conditions for inventive and comparative examples

[0445]

[0446] Table 2 Properties of inventive and comparative examples

[0447]

[0448] From Table 2 and Figures 1 and 2 it can be seen that the inventive examples synthesised using a blend of catalysts a3) and b2) have a better balance of flexural modulus to haze and flexural modulus to NIS compared to polypropylenes synthesised from a3) or b2) alone (CE2 and CE3 respectively). These effects can still be further enhanced by the addition of nucleating agents (IE4 and IE5).

[0449] In addition to these features, the inventive examples are characterised by an advantageous low T m - T c This is particularly useful for applications in moulding as it allows for a faster moulding process in which the moulded article cures more quickly.

[0450] Furthermore, when compared to an alternative catalyst blend (CE4) in which a Ziegler-Natta catalyst uses phthalate internal donors, the balance of flexural modulus to haze is significantly improved (i.e. lower haze coupled with higher flexural modulus). The NIS of CE4 is slightly higher than the NIS of the inventive examples; however, this is not a surprising result as it is well known that high molecular weight polypropylenes (i.e. lower MFR2) have higher impact strength.

[0451] In addition to the improved balance of flexural modulus and haze, the production rates of the inventive catalyst blends both after R2 and at the end of the polymerization process are significantly better than the production rates of CE4.< / mmmm> ​< / mmmm> < / mmmm> ​

Claims

1. A method for preparing isotactic propylene polymer compositions, comprising the following steps: (a) A Ziegler-Natta type catalyst comprising a magnesium halide support, a titanium component, and an internal donor (ID) is prepolymerized with a monomer (I) having the following general formula in the presence of an alkylaluminum co-catalyst and an external donor (ED) to obtain a catalyst composition (II), wherein the internal donor is not a phthalate and the Ziegler-Natta type catalyst is phthalate-free. CH2=CH-CHR 1 R 2 (I) wherein R 1 and R 2 are individual alkyl groups having one or more carbon atoms, or form an optionally substituted saturated, unsaturated or aromatic ring or fused ring system containing 4 to 20 carbon atoms, said catalyst composition (II) comprising from 25 to 95 wt.-% of isotactic polymer based on said monomer (I); (b) The catalyst composition (II) is mixed with a supported metallocene catalyst (III) suitable for the production of isotactic polypropylene in an inert medium at a weight ratio of 1:99 to 55:45 (II):(III) to obtain a catalyst blend (IV). (c) The catalyst blend (IV) is used in one or more reaction steps to polymerize propylene and optionally one or more comonomers selected from ethylene and α-olefins containing 4 to 12 carbon atoms to obtain isotactic propylene homopolymers or copolymers (V). (d) The isotactic propylene homopolymer or copolymer (V) is melt-mixed with additives and then granulated; The metallocene catalyst (III) comprises (i) Metallocene complexes having general formula (VI) Each X is independently a σ-donor ligand. L is a divalent bridge selected from -R'2C-, -R'2C-CR'2-, -R'2Si-, -R'2Si-SiR'2-, -R'2Ge-, wherein each R' is independently a hydrogen atom or a C1-C10 hydrocarbon group optionally containing one or more heteroatoms from groups 14 to 16 of the periodic table, or two R' groups together can form a ring, 20 - a hydrocarbon group or a fluorine atom, or optionally two R' groups together can form a ring, each R 1 independently the same or can be different and are hydrogen, linear or branched C1-C6-alkyl, C 7-20 - aralkyl, C 7-20 - alkylaryl or C 6-20 - aryl or OY groups, wherein Y is C 1-10 - hydrocarbyl, and optionally two adjacent R 1 groups can be part of the ring comprising the phenyl carbon to which they are bonded, each R 2 are independently the same or can be different and are CH2-R 8 group, wherein R 8 is H or linear or branched C 1-6 -alkyl, C 3-8 -cycloalkyl, C 6-10 -aryl, R 3 Ci-C6-alkyl, C 7-20 - aralkyl, C 7-20 - alkylaryl or C6-C 20 - aryl, R 4 is a C(R 9 )3group, wherein R 9 is a linear or branched C1-C6-alkyl group, R 5 is hydrogen or an aliphatic C1-C20 hydrocarbon group optionally containing one or more heteroatoms from groups 14 to 16 of the periodic table; 20 - a hydrocarbon group; R 6 It is aliphatic C1-C atoms, which are hydrogen or optionally contain one or more heteroatoms from groups 14 to 16 of the periodic table. 20 -hydrocarbon group; or R 5 and R 6 They can form a 5-membered saturated carbon ring, which is optionally bound by n groups R. 10 Replacement, where n is 0 to 4; Each R 10 Same or different, and can be C1-C 20 - A hydrocarbon group, or optionally a C1-C group containing one or more heteroatoms belonging to groups 14 to 16 of the periodic table. 20 -Hydrocarbon group; R 7 It is an H or a straight-chain or branched C1-C6-alkyl group or optionally surrounded by 1 to 3 R groups. 11 Substituted aryl or heteroaryl groups having 6 to 20 carbon atoms, Each R 11 Independently identical or capable of being different, and being hydrogen, straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -alkylaryl or C 6-20 -Aryl or OY group, where Y is C 1-10 -Hydrocarbon group, (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and (iii) Silica support.

2. The method according to claim 1, wherein the external donor (ED) in step (a) is a silane.

3. The method according to claim 2, wherein the external donor (ED) in step (a) is a silane having the following general formula. R A p R B q Si(OR C ) (4-p-q) Where R A R B and R C Let R represent a hydrocarbon group, where p and q are numbers in the range of 0 to 3, and their sum p + q is equal to or less than 3, where R A R B and R C They can choose independently from each other, and can be the same or different.

4. The method according to claim 3, wherein R A R B and R C Indicates alkyl or cycloalkyl.

5. The method according to any one of claims 1 to 4, wherein the internal donor (ID) of the Ziegler-Natta type catalyst in step (a) is a (di) ester of a non-phthalic acid carboxylic (di) acid.

6. The method according to any one of claims 1 to 4, wherein the internal donor (ID) of the Ziegler-Natta type catalyst in step (a) is a diester of a monounsaturated dicarboxylic acid.

7. The method according to any one of claims 1 to 4, wherein the internal donor (ID) of the Ziegler-Natta type catalyst in step (a) is maleate, citrate or cyclohexene-1,2-dicarboxylic acid ester.

8. The method according to any one of claims 1 to 4, wherein the monomer (I) is selected from vinylcyclohexane, vinylcyclopentane and 4-methylpent-1-ene.

9. The method according to any one of claims 1 to 4, wherein the weight ratio (II):(III) of the catalyst composition (II) and the supported metallocene catalyst (III) in the catalyst blend (IV) formed in step (b) is in the range of 5:95 to 40:

60.

10. The method according to any one of claims 1 to 4, wherein the polymerization step (c) comprises a prepolymerization step with propylene and optionally a small amount of ethylene in the liquid phase at a temperature of 15 to 35°C, followed by at least two main polymerization steps in the liquid phase and / or gas phase at a temperature of 65 to 95°C.

11. The method according to any one of claims 1 to 4, wherein the melt mixing step (d) is carried out in a continuous melt mixing apparatus selected from the group consisting of a single-screw extruder, a twin-screw extruder, and a co-kneader at a temperature range of 180 to 280°C.

12. The method according to any one of claims 1 to 4, wherein the additive comprises an antioxidant, an acid remover, and optionally a nucleating agent.

13. An isotactic propylene polymer composition, which is a reactor blend produced by the method according to any one of claims 1 to 12.

14. The isotactic propylene polymer composition according to claim 13, comprising the following: (i) 45 to 99% by weight of metallocene-based homopolymers or copolymers relative to the total weight of the isotactic propylene polymer composition. (ii) 1 to 55% by weight of Ziegler-Nattaky homopolymer or copolymer relative to the total weight of the isotactic propylene polymer composition. (iii) 5 to 500 ppm by weight of the polymer nucleating agent formed in step (a) relative to the total weight of the isotactic propylene polymer composition, and (iv) up to 2.0% by weight of other additives relative to the total weight of the isotactic propylene polymer composition, wherein the combined weight of components (i) to (iv) totals 100% by weight.

15. The isotactic propylene polymer composition according to claim 14, wherein the other additives include antioxidants, deacidifiers, UV stabilizers, antistatic agents, and nucleating agents.

16. The isotactic propylene polymer composition according to any one of claims 13 to 15, having one or more of the following properties: (i) Melt flow rate MFR2, measured according to ISO 1133 at 230 °C and 2.16 kg load, in the range of 10 to 500 g / 10 min. (ii) a comonomer content of up to 5.0% by weight, (iii) Pass rate in the range of 96.0% to 99.9% 13 Regularity of isosteretic five-unit group determined by C-NMR spectroscopy <mmmm> ，< / mmmm> (iv) 2,1-zone defect content in the range of 0.2 to 1.2 mol%, and (v) Content of xylene cold solubles (XCS) in the range of 0.9 to 7.5% by weight, determined at 25°C according to ISO 16152.

17. The isotactic propylene polymer composition according to claim 16, wherein the comonomer is ethylene.

18. The isotactic propylene polymer composition according to any one of claims 13 to 15, having one or more of the following properties: (i) Melting temperature T in the range of 150 to 160 °C m , (ii) Crystallization temperature T in the range of 120 to 132 °C c ,and (iii) T in the range of 15 to 31°C m and T c The difference between (T) m –T c ), Where T m and T c Both were determined by differential scanning calorimetry (DSC) in accordance with ISO 11357 / Part 3 / Method C2 in a heating / cooling / heating cycle at a scan rate of 10 °C / min over a temperature range of -30 to +225 °C.

19. A film or molded article comprising at least 95% by weight of an isotactic propylene polymer composition according to any one of claims 13 to 18.

20. The molded article according to claim 19, wherein it is an injection-molded article, characterized in that... According to ASTM D1003, the haze is less than 50% at a thickness of 1 mm.

21. Use of a catalyst mixture for the production of isotactic propylene homopolymer or copolymer compositions, said catalyst mixture comprising: (a) 45 to 95% by weight of a metallocene catalyst (III) relative to the total weight of the catalyst mixture, wherein the metallocene catalyst (III) comprises (i) Metallocene complexes having general formula (VI) Each X is independently a σ-donor ligand. L is a divalent bridge selected from -R'2C-, -R'2C-CR'2-, -R'2Si-, -R'2Si-SiR'2-, and -R'2Ge-, wherein each R' is independently a hydrogen atom or optionally contains one or more heteroatoms from groups 14 to 16 of the periodic table. 20 - A hydrocarbon group or a fluorine atom, or optionally two R' groups together, can form a ring. Each R 1 Independently identical or capable of being different, and being hydrogen, straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -alkylaryl or C 6-20 -Aryl or OY group, where Y is C 1-10 - hydrocarbon group, and optionally two adjacent R 1 The groups can be part of a ring containing the phenyl carbon to which they are bonded. Each R 2 Independently identical or capable of being different, and being CH2-R 8 Group, wherein R 8 C is H or a straight chain or a branched chain 1-6 -alkyl, C 3-8 -cycloalkyl, C 6-10 -Aryl R 3 It is a straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -Alkaryl or C6-C 20 -Aryl R 4 For C(R) 9 )3 groups, of which R 9 It is a straight-chain or branched C1-C6-alkyl group. R 5 It is aliphatic C1-C atoms, which are hydrogen or optionally contain one or more heteroatoms from groups 14 to 16 of the periodic table. 20 -Hydrocarbon group; R 6 It is aliphatic C1-C atoms, which are hydrogen or optionally contain one or more heteroatoms from groups 14 to 16 of the periodic table. 20 -hydrocarbon group; or R 5 and R 6 They can form a 5-membered saturated carbon ring, which is optionally bound by n groups R. 10 Replacement, where n is 0 to 4; Each R 10 Same or different, and can be C1-C 20 - A hydrocarbon group, or optionally a C1-C group containing one or more heteroatoms belonging to groups 14 to 16 of the periodic table. 20 -Hydrocarbon group; R 7 It is an H or a straight-chain or branched C1-C6-alkyl group or optionally surrounded by 1 to 3 R groups. 11 Substituted aryl or heteroaryl groups having 6 to 20 carbon atoms, Each R 11 Independently identical or capable of being different, and being hydrogen, straight-chain or branched C1-C6-alkyl, C 7-20 -Aryl group, C 7-20 -alkylaryl or C 6-20 -Aryl or OY group, where Y is C 1-10 -Hydrocarbon group, (ii) a cocatalyst system comprising a boron-containing cocatalyst and / or an aluminoxane cocatalyst, and (iii) Silica support, and (b) 5 to 55% by weight of a Ziegler-Natta type catalyst composition (II) relative to the total weight of the catalyst mixture, wherein the Ziegler-Natta type catalyst composition (II) comprises i) A Ziegler-Natta type catalyst comprising a magnesium halide support, a titanium component and an internal donor (ID), wherein the internal donor is not a phthalate and the Ziegler-Natta type catalyst is phthalate-free. ii) Alkyl aluminum co-catalyst; iii) External donor (ED) The Ziegler-Natta catalyst composition has been modified by polymerization of a monomer (I) having the following general formula. CH2=CH-CHR 1 R 2 (I) Where R 1 and R 2 The monomer (I) is a single alkyl group having one or more carbon atoms, or forms an optionally substituted saturated, unsaturated, or aromatic ring or fused ring system containing 4 to 20 carbon atoms, such that the Ziegler-Natta type catalyst composition (II) contains 25 to 95% by weight of an isotactic polymer based on the monomer (I). The isotactic propylene homopolymer or copolymer composition has one or more of the following properties: (i) Melt flow rate MFR2, measured according to ISO 1133 at 230°C and 2.16 kg load, in the range of 5 to 500 g / 10 min. (ii) a comonomer content of up to 6.0% by weight, (iii) Pass rate in the range of 96.0% to 99.9% 13 Regularity of isosteretic five-unit group determined by C-NMR spectroscopy <mmmm> ，< / mmmm> (iv) 2,1-zone defect content in the range of 0.2 to 1.2 mol%, and (v) Content of xylene cold solubles (XCS) in the range of 0.9 to 9.0% by weight, determined at 25°C according to ISO 16152.

22. The use according to claim 21, wherein the comonomer is ethylene.

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