CN114729068A

CN114729068A - Catalyst composition for the polymerization of olefins

Info

Publication number: CN114729068A
Application number: CN202080079097.3A
Authority: CN
Inventors: 希卡林·塔米亚库; 方皮蒙·翁马哈西里昆; 派拉特·菲里亚维鲁特
Original assignee: Thai Polyethylene Co Ltd
Current assignee: Thai Polyethylene Co Ltd
Priority date: 2019-11-29
Filing date: 2020-11-27
Publication date: 2022-07-08
Also published as: WO2021105373A1; EP4065610A1; JP2023505758A

Abstract

The present invention relates to a process for preparing a solid procatalyst suitable for use in a ziegler-natta type catalyst composition for polymerizing olefin monomers. The process is for preparing a procatalyst comprising a transition metal, Mg, a halogen, a modifier and an internal donor and comprises reacting a halide of the transition metal with a magnesium alkoxide to provide a solid reaction product comprising the transition metal supported on a magnesium halide based support and contacting the solid reaction product with the internal donor and the modifier.

Description

Catalyst composition for the polymerization of olefins

Technical Field

The present invention relates to a process for preparing a solid procatalyst (pro-catalyst) suitable for use in a ziegler-natta type catalyst composition for polymerizing olefin monomers. The invention also extends to a procatalyst, a ziegler-natta type catalyst composition comprising the procatalyst and the use of each of these for polymerizing olefin monomers. The procatalyst or catalyst composition is useful for producing phthalate free polypropylene in high yield, high melt flow rate and high tacticity.

Background

Ziegler-Natta catalyst compositions/systems are well known in the art for polymerizing olefins. Typically, the ziegler-natta catalyst composition/system comprises (I) a solid procatalyst component comprising a transition metal (e.g. titanium, magnesium), an electron donor compound and a halogen atom, and (II) a cocatalyst component, which is typically an organoaluminum compound. It is desirable to improve the activity and stereospecificity (stereospecificity) of ziegler-natta catalyst compositions, and a widely used method in this regard is the use of electron donating compounds. Generally, electron donating compounds can be divided into two groups, (1) internal electron donors and (2) external electron donors for use with solid ziegler natta procatalyst and cocatalyst components. By varying the polymerization conditions, in particular by using an external electron donor, various polypropylene products can be produced. The external electron donor includes organic compounds containing O, Si, N, S and/or P. Typically, the external donor compounds are based on silane, ketone, amide, amine, and thiol compounds, among others, the most common compounds being organosilicon compounds containing Si-O-C and/or Si-N-C bonds. With respect to the internal donor, attention has recently been raised regarding environmental problems using phthalate derivatives as the internal donor, and attention regarding human body contact, for example, with polypropylene products containing phthalate derivatives. Therefore, it would be highly desirable to provide alternative internal electron donors to phthalate compounds. WO 2018/059955a1 discloses a process for preparing a procatalyst for polymerizing olefins. The process involves a solid support Mg (OR)¹)_xX¹ _2-x(wherein 0)<x<2, preferably R¹Is ethyl, and X¹Cl), which is a two-step activationAn adduct of the solid support and the at least two activating compounds is produced. This process uses a grignard reagent to prepare the solid support, which may make it difficult to control the morphology of the catalyst.

The internal electron donor is a component of the ziegler-natta catalyst composition, which is incorporated during the catalyst preparation. Well-known internal electron donors include ethers, esters, ketones, amines, alcohols, heterocyclic organic compounds, phenols, and phosphines. The structure of the internal electron donor can affect catalyst activity, tacticity, hydrogen (melt flow rate of the polymer), and comonomer response. Thus, the molecular weight, molecular weight distribution, and isotacticity of the resulting polymer can be significantly dependent on the molecular structure of the internal electron donor (see, e.g., ACS cat. 2017,7, 4509-. Accordingly, much effort has been devoted to developing new internal donors for Ziegler-Natta catalysts to improve the properties of the polymers they are used to produce. Common internal electron donor compounds suitable for incorporation into ziegler-natta catalysts and known in the art include ester, amine, alcohol, heterocyclic organic compounds, phthalate, diether, and succinate compounds. Diether compounds have been disclosed to be developed for the production of phthalate-free polypropylene (Journal of Applied Polymer Science, Vol.99,1399-1404 (2006)). One of the most widely used is 9, 9-bis (methoxymethyl) fluorene and its derivatives. Such diether internal donors are associated with significant improvements in activity and hydrogen response when used in ziegler-natta catalyst compositions. However, it is also accompanied by moderate stereoselectivity, and more importantly, stereoselectivity which is inferior to that of phthalate type catalysts, thus limiting the application of this internal donor in the development of phthalate free polypropylene production. Therefore, in an effort to produce phthalate free polypropylene, it is desirable to improve the stereoselectivity of diether ziegler-natta catalysts. In an effort to produce phthalate-free polypropylene, it would be particularly desirable to improve the stereoselectivity of diether ziegler-natta catalysts without compromising any of the other advantageous properties associated with these catalysts. There is a need to provide new ziegler-natta catalyst compositions that produce polypropylene of high tacticity.

The present invention seeks to address one or more of the aforementioned problems or to meet one or more of the aforementioned desires/needs.

Disclosure of Invention

In a first aspect, the present invention provides a process for the preparation of a procatalyst comprising a transition metal, Mg, halogen, a modifier and an internal donor, wherein the process comprises (I) contacting a halide of the transition metal and a magnesium alkoxide to provide a solid reaction product comprising the transition metal supported on a magnesium halide based support, and (ii) contacting the solid reaction product with the internal donor and the modifier, wherein the modifier has formula (I)

Wherein R is₁And R₂Each independently hydrogen or alkyl having 1 to 6 carbon atoms, and R₃、R₄、R₅、R₆And R₇Each independently selected from hydrogen, heteroatoms or hydrocarbyl groups.

In another aspect, the present invention provides a procatalyst comprising a transition metal, Mg, halogen, a modifier and an internal donor obtained/obtainable by the process of the first aspect of the invention. For example, the procatalyst may be obtained/obtainable by: (i) contacting a halide of a transition metal and a magnesium alkoxide to provide a solid reaction product comprising the transition metal supported on a magnesium halide-based support, and (ii) contacting the solid reaction product with an internal donor and a modifier, wherein the modifier has the formula (I)

The procatalyst of the invention is suitable for use in a catalyst composition for the polymerization of olefin monomers. More specifically, the procatalyst is suitable for use in the polymerization of olefin monomers with an organoaluminum cocatalyst and optionally an external donor. The procatalyst may be free of any phthalate ester (phthalate being the ester of phthalic acid or phthalate ester and derivatives thereof), i.e. in one embodiment the procatalyst is free of any phthalate ester. Advantageously, the procatalyst of the present invention may be used in the polymerization of olefin monomers to produce highly isotactic polymers/copolymers, such as in the polymerization of polypropylene to produce highly isotactic polypropylene.

In another aspect, the present invention provides a catalyst composition for polymerizing olefin monomers comprising the procatalyst of the present invention and a cocatalyst. The cocatalyst comprises an organoaluminum compound.

In another aspect, the present invention provides the use of a procatalyst of the invention or a catalyst composition comprising the procatalyst of the invention as described above for polymerizing olefin monomers. In particular, the present invention provides the use of a procatalyst according to the invention or a catalyst composition comprising the procatalyst according to the invention as described above for the preparation of highly stereoregular polyolefins, such as polyolefins having a mmmm content of at least 95%. In particular, it has surprisingly been found that the procatalyst according to the invention or the catalyst composition according to the invention can be used to prepare polypropylene having a higher stereoselectivity (in terms of mmmm content) than polypropylene prepared using conventional diether catalysts.

In another aspect, the present invention provides a process for the preparation of a polyolefin, which process comprises polymerising an olefin monomer in the presence of a catalyst composition comprising a procatalyst according to the first aspect of the invention, a cocatalyst comprising an organoaluminium compound and optionally an external donor. In another aspect, the present invention provides a polyolefin thus obtained or obtainable by said process. The polyolefin may be a homopolymer or a copolymer, such as an impact copolymer polypropylene.

Definition of

The term "ziegler-natta (ZN) catalyst composition/system" as used herein refers to a procatalyst comprising a transition metal halide (e.g., a titanium halide, a chromium halide, a hafnium halide, a zirconium halide or a vanadium halide) supported on a metal or metalloid compound (e.g., a magnesium compound or a silica compound) and in combination with a cocatalyst. The procatalyst is also known as the solid component of the ziegler-natta (ZN) catalyst composition/system. The cocatalyst is typically an organoaluminum compound.

The term "catalyst system" as used herein is interchangeable with the term "catalyst composition" and refers to a procatalyst that includes any optional activator, internal electron donor, and modifier, as well as combinations with cocatalysts and any external electron donor.

The terms "internal electron donor", "internal donor", "ID" as used herein are interchangeable and refer to an electron donating compound containing one or more atoms of oxygen (O) and/or nitrogen (N) which is incorporated into the solid procatalyst during preparation of the procatalyst. Suitable internal electron donors are generally described in the prior art for preparing solid procatalysts for use in ziegler natta catalyst systems for the polymerization of propylene.

The terms "external electron donor", "external donor" and "ED" as used herein are interchangeable and refer to the electron donor compound used in conjunction with the procatalyst in the polymerization of olefin monomers. During the preparation of the procatalyst, the external electron donor is not incorporated into the solid procatalyst, but is added to the polymerization reaction independently of the procatalyst. The external electron donor function is to donate an electron to another compound and may affect the properties of the catalyst composition/system.

The term "homopolymer" as used herein refers to a polymer consisting essentially of repeat units derived from the same monomer. The homopolymer may for example comprise at least 99 wt%, more preferably at least 99.5 wt%, still more preferably at least 99.95 wt%, and still more preferably at least 99.95 wt%, for example 100 wt% of repeat units derived from the same monomer.

The term "propylene homopolymer" as used herein refers to a polymer consisting essentially of repeat units derived from propylene. The homopolymer may for example comprise at least 99 wt%, more preferably at least 99.5 wt%, still more preferably at least 99.95 wt%, and still more preferably at least 99.95 wt%, for example 100 wt% of repeating units derived from propylene.

As used herein, "impact copolymer polypropylene" refers to a polymer comprising a propylene homopolymer or copolymer matrix and an ethylene-propylene rubber phase dispersed in the matrix.

The term "propylene copolymer" as used herein refers to a polymer comprising repeat units derived from propylene and at least one other comonomer. Typically, the propylene copolymer comprises at least 0.05 wt%, more preferably at least 0.1 wt%, still more preferably at least 0.4 wt% of repeat units derived from at least one other comonomer, wherein the wt% is based on the propylene copolymer. The propylene copolymer will typically not comprise more than 15 wt% of repeat units derived from at least one other comonomer. Typically, the propylene copolymer comprises at least 85 wt%, more preferably at least 90 wt%, and still more preferably at least 95 wt% propylene monomer repeat units.

The terms "modifier" and "M" as used herein are interchangeable and refer to the electron donating compound containing one or more atoms of oxygen (O) and/or nitrogen (N) that is introduced into the procatalyst during the preparation of the solid procatalyst.

As used herein, the term "hydrocarbyl" or "hydrocarbyl group" refers to a monovalent radical derived from a hydrocarbon. Hydrocarbyl groups include, for example, alkyl, alkenyl, aryl, arylalkyl, arylalkenyl, alkoxycarbonyl, and alkylaryl groups.

As used herein, "heteroatom" refers to an atom selected from group 13, 14, 15, 16 or 17 of the IUP periodic table of elements and may be described As a heteroatom selected from B, Al, Ga, In, Si, Ge, Sn, N, P, As, O, S, Se, Te, F, Cl, Br and I.

The term "polypropylene" as used herein refers to a polymer of propylene.

The terms "XS", "xylene solubles", "xylene soluble fraction" as used herein are interchangeable and refer to the xylene soluble fraction, expressed as the percentage of polymer that does not precipitate out when the polymer solution is cooled in xylene. The above polymer solution was placed under reflux conditions and then cooled from the boiling point of xylene to 25 ℃. The xylene soluble fraction is measured according to ASTM D5492-10 (Standard test method for determining xylene solubles in propylene plastics).

The term "productivity" as used herein refers to kilograms of polymer produced per gram of solid procatalyst consumed in the polymerization reactor per hour.

As used herein, the term "comprising" is inclusive or open-ended and does not exclude additional unrecited elements or method steps, and is intended to include as alternative embodiments the phrases "consisting essentially of … …" and "consisting of … …", wherein "consisting of … …" excludes any unspecified elements or steps, and "consisting essentially of … …" allows for the inclusion of additional unrecited elements or steps that do not materially affect the essential or essential and novel characteristics of the contemplated composition or method.

Detailed Description

According to a first aspect, the present invention provides a process for the preparation of a procatalyst comprising a transition metal, Mg, halogen, a modifier and an internal donor, wherein the process comprises (I) contacting a halide of the transition metal and a magnesium alkoxide to provide a solid reaction product comprising the transition metal supported on a magnesium halide based support, and (ii) contacting the solid reaction product with the internal donor and the modifier, wherein the modifier has formula (I)

The transition metal may be selected from titanium, chromium, hafnium, zirconium and vanadium. Preferably, the transition metal is titanium. Halides of transition metals are halogenating agents for magnesium alkoxide halides. The halide provides the halogen element of the procatalyst. The halide may be selected from chloride, bromide and iodide. Preferably, the halide is chloride. Typically, the halide of the transition metal is titanium chloride. Preferably, the halide of the transition metal is titanium tetrachloride. For example, when the transition metal halide is titanium chloride, the procatalyst includes titanium, Mg, chlorine, an internal donor and a modifier (also referred to as a modifier).

The process of the present invention involves step (i) whereby a halide of a transition metal and a magnesium alkoxide are contacted such that they react to provide a solid reaction product comprising the transition metal supported on a magnesium halide based support. Further, the method involves step (ii), whereby the solid reaction product is contacted with an internal donor and a modifying agent to provide a solid reaction product comprising the internal donor and the modifying agent. In the process of the invention, the transition metal halide and the magnesium alkoxide are reacted together. The internal donor and modifier are incorporated into the solid reaction product and do not themselves participate in the chemical reaction. The process of the present invention produces a solid procatalyst (the solid reaction product includes the transition metal supported on a magnesium halide based support and includes an internal donor and a modifier). The process is preferably carried out in the absence of any phthalate, thus obtaining a solid procatalyst which does not contain any phthalate. The procatalyst may be considered the solid component of the Ziegler-Natta catalyst composition (or Ziegler-Natta catalyst system).

It has been found that by using a magnesium alkoxide in the preparation of the support of the procatalyst of the present invention, a procatalyst having a high porosity and a high surface area is obtained. In particular, it has been found that the morphology of the procatalyst of the invention is the same as or similar to the morphology of the magnesium alkoxide used to prepare the procatalyst of the invention. For example, the particle size of the procatalyst may be within about 10% of the particle size of the magnesium alkoxide. Clearly, a procatalyst with high porosity and high surface area is advantageous. Further, it has been found that the use of the procatalyst of the present invention is advantageous, particularly in the preparation of impact copolymer polypropylene. For example, the procatalysts of the present invention are useful in the preparation of impact copolymer polypropylene having a high rubber phase content. Impact copolymer polypropylenes having excellent mechanical properties can be prepared using the procatalysts of the present invention because the homopolymer portion has a high tacticity and a high content of rubber phase. By balancing this tacticity of the homopolypropylene fraction with a high content of rubber phase, an impact copolymer polypropylene with excellent mechanical properties can be obtained.

The magnesium alkoxide, also referred to herein as dialkoxymagnesium, may have the formula MgOR₁₂OR₁₃Wherein R is₁₂And R₁₃Independently a hydrocarbyl group containing 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms or more preferably 2 carbon atoms. The hydrocarbyl group may be an alkyl group. An exemplary magnesium alkoxide is magnesium ethoxide, i.e., MgOR₁₂OR₁₃Wherein R is₁₂And R₁₃Each is ethyl. The magnesium alkoxide is solid and includes particles (i.e., in particulate form). The magnesium alkoxide is preferably in the form of a granulate or powder. It may comprise spherical or approximately spherical particles, for example, the particles do not necessarily have to have a true spherical shape, for example they may be potato shaped. Preferably, the magnesium alkoxide comprises particles having a particle shape such that their average ratio (l/w) of major axis diameter (l) to minor axis diameter (w) is 3 or less, preferably 1 to 2, more preferably 1 to 1.5. When 500 particles are taken and measured using SEM images, the average particle diameter of the dialkoxymagnesium may be 1 to 200 according to the average particle diameter D50 (i.e., the particle diameter at 50% in the cumulative particle diameter distribution). The particle size distribution refers to the number of particles of each falling within the various diameter ranges, expressed as a percentage of the total number of particles of all diameters in the sample. An average particle diameter D50 of 200 μm is preferred. This means that 50% of the number of particles in the sample have a diameter larger than 200 μm and 50% of the number of particles in the sample have a diameter smaller than 200 μm. An average particle size D50 of 5-150 microns is more preferred. In the case of dialkoxymagnesium, the average particle diameter D50 is preferably 1 to 100 μm, more preferably 5 to 80 or 50 μm, and even more preferably 10 to 40 μm. Further, a narrower particle size distribution with small amounts of fine powder and coarse powder is desirable.Preferably, the content of particles of dialkoxymagnesium having a diameter of 5 μm or less is 20% or more, or more preferably 10% or more (these are quantity percentages) when measured using SEM images. Preferably, the dialkoxymagnesium has a content of particles having a diameter of 100 μm or more of 10% or less, more preferably 5% or less (these are quantity percentages). Further, the particle size distribution, ln (D90/D10) (where D90 is the particle size at 90% in the cumulative particle size distribution and D10 is the cumulative particle size at 10% in the cumulative particle size distribution), is preferably 3 or less, more preferably 2 or less. Methods for producing dialkoxymagnesium as described above are described in, for example, JP-A-58-41832, JP-A-62-51633, JP-A-3-74341, JP-A-4-368391, and JP-A-8-73388.

The modifier has the formula (I):

wherein R is₁And R₂Each independently hydrogen or alkyl having 1 to 6 carbon atoms, and R₃、R₄、R₅、R₆And R₇Each independently selected from hydrogen, heteroatoms or hydrocarbyl groups. R₁And R₂And may independently be hydrogen or an alkyl group having 3 carbon atoms. R₁And R₂May independently be hydrogen or methyl. Preferably, R₁And R₂Is an alkyl group (having 1 to 6 or 1 to 3 carbon atoms), and more preferably, R is₁And R₂At least one of which is methyl. R₃、R₄、R₅、R₆And R₇Each independently selected from hydrogen, heteroatoms or hydrocarbyl groups. The heteroatom may be selected from B, Al, Ga, In, Si, Ge, Sn, N, P, As, O, S, Se, Te, F, Cl, Br and I. Preferably, the heteroatom is a halide. Preferably, the hydrocarbyl group is selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl, or alkylaryl groups, and one or more combinations thereof. The hydrocarbyl group may be linear, branched or cyclic. The hydrocarbyl group may be substituted or unsubstituted, and may contain one or more heteroatoms. PreferablyThe hydrocarbyl group has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, even more preferably 1 to 6 carbon atoms. More preferably, R₃、R₄、R₅、R₆And R₇Each is hydrogen. Thus, in one embodiment, R₁And R₂Each independently hydrogen or alkyl having 1 to 6 carbon atoms, and R₃、R₄、R₅、R₆And R₇Each is hydrogen.

Examples of the modifier include benzamide, methylbenzamide, and dimethylbenzamide. Other examples include monoethylbenzamide, diethylbenzamide, and methylethylbenzamide. An exemplary modifier is dimethyl benzamide.

The amount of modifier used in the process of the invention may be selected such that the procatalyst contains the modifier in an amount of from 0.15 to 8 wt%, as measured by NMR and based on the total weight of the procatalyst. Preferably, the amount of modifier used in the reaction is such that the modifier is present in the procatalyst in an amount of from 0.3 to 6 wt%, more preferably from 0.5 to 4 wt%. The amount of modifier used in the reaction may be such that the modifier is present in the procatalyst in an amount of from 0.1 to 2.0 wt%, preferably in an amount of from 0.1 to 0.4 wt%.

The internal donor may be a diether compound. Suitable diether compounds are those known in the art as internal donors for ziegler-natta catalyst systems. Suitable diether compounds are described, for example, in US 2016/0311947. Preferred diether internal donor compounds include 1, 3-diether compounds represented by the structure (II):

wherein: r is₁₀And R₁₁Identical or different and each selected from the group consisting of saturated or unsaturated aliphatic hydrocarbon radicals of 1 to about 20 carbon atoms, and R₈And R₉Are the same or different and are each selected from the group consisting of linear, cyclic, or branched hydrocarbon radicals having from 1 to about 40 carbon atoms. Preferably, R₁₀And R₁₁Each independently selected from alkyl groups of 1 to about 10 carbon atoms. More preferably, R₁₀And R₁₁Each independently selected from alkyl groups of 1 to 4 carbon atoms. Even more preferably, R₁₀And R₁₁Each independently selected from methyl or ethyl. Even more preferably, R₁₀And R₁₁Each of which is methyl. Preferably, R₈And R₉Each independently selected from alkyl of 1 to about 20 carbon atoms, alkenyl of 2 to about 20 carbon atoms, aryl of 6 to about 20 carbon atoms, arylalkyl of 7 to about 40 carbon atoms, alkylaryl of 7 to about 40 carbon atoms, or arylalkenyl of 8 to about 40 carbon atoms, and may contain one or more heteroatoms such as Si, B, Al, O, S, N, or P, and/or may contain one or more halogen atoms such as F, Cl or Br, and/or R₈And R₉May be linked together to form a hydrocarbon ring system (such as fluorene). Thus, in one embodiment, R₁₀And R₁₁Each independently selected from alkyl groups of 1 to about 10 carbon atoms, and R₈And R₉Each independently selected from alkyl of 1 to about 20 carbon atoms, alkenyl of 2 to about 20 carbon atoms, aryl of 6 to about 20 carbon atoms, arylalkyl of 7 to about 40 carbon atoms, alkylaryl of 7 to about 40 carbon atoms, or arylalkenyl of 8 to about 40 carbon atoms, and may contain one or more heteroatoms such as Si, B, Al, O, S, N, or P, and/or may contain one or more halogen atoms such as F, Cl or Br, and/or R₈And R₉May be linked together to form a hydrocarbon ring system (such as fluorene).

Preferably, the diether internal donor compound is selected from: 2, 2-diisobutyl-1, 3-dimethoxypropane; 2, 2-diisopropyl-1, 3-dimethoxypropane; 2, 2-dicyclopentyl-1, 3-dimethoxypropane; 2-isopropyl-2-isoamyl-1, 3-dimethoxypropane; 2-isopropyl-2-isobutyl-1, 3-dimethoxypropane; 2-isopropyl-2-cyclopentyl-dimethoxypropane; 2-ethyl-2-tert-butyl-1, 3-dimethoxypropane or the corresponding 1, 3-diethoxypropane analogue; 9, 9-bis (methoxymethyl) fluorene; and 9, 9-bis (ethoxymethyl) fluorene.

The amount of internal donor used in the process of the invention may be selected such that the procatalyst contains the internal donor in an amount of from 10 wt% to 30 wt%, as measured by NMR and based on the total weight of the procatalyst. Preferably, the amount of internal donor used in the process of the invention is such that the amount of internal donor in the procatalyst is from 15 wt% to 28 wt%, more preferably from 20 wt% to 28 wt% (e.g. 25 wt%). The amount of internal donor used in the process of the invention may be such that the internal donor is present in the procatalyst in an amount of from 15 wt% to 25 wt%.

The relative amounts of modifier and internal donor used in the process of the invention may be selected such that the procatalyst contains the modifier of formula (I) and the internal donor in a molar ratio (M/ID) of from 0.04 to 0.50. Preferably, the molar ratio M/ID is from 0.04 to 0.18 or 0.17, from 0.04 to 0.12, or from 0.05 to 0.10. The molar ratio M/ID may be from 0.005 to 0.5, or from 0.01 to 0.3. In particular, it has been found that even at such low M/ID ratios, the resulting procatalysts can be used to obtain polymers of high tacticity, such as polypropylene of high tacticity. Thus, highly isotactic polypropylene can be obtained using relatively low levels of benzamide modifier. Furthermore, it has been found that using a lower amount of benzamide modifier results in a procatalyst having an improved morphology, e.g., the procatalyst will have a lower amount of fine particles and most of the catalyst particles will have a similar size. Preferably, the procatalyst of the present invention contains little or no fine particles (i.e., particles less than 5 microns). This can be qualitatively determined from SEM (scanning electron microscope) images. A smaller amount of fine particles in the main catalyst is preferred because a larger amount of fine particles in the main catalyst may cause flowability problems, such as clogging of the reactor, and may reduce heat removal efficiency.

The process of the present invention for preparing a procatalyst comprising a transition metal, Mg, halogen, a modifier and an internal donor comprises (i) contacting a halide of the transition metal and a magnesium alkoxide to provide a solid reaction product comprising the transition metal supported on a magnesium halide based support, and (ii) contacting the solid reaction product with the internal donor and the modifier.

The process of the invention involves the following step (i): the halide of the transition metal and the magnesium alkoxide are contacted so that they react to form a solid reaction product comprising the transition metal supported on a magnesium halide-based support. Typically, in this step, a halide of a transition metal and a magnesium alkoxide are mixed to form a reaction mixture. The magnesium alkoxide, which is a solid, may be suspended in a hydrocarbon solvent, in which case the transition metal halide is added to the suspension to form the reaction mixture. Preferably, the transition metal halide is added to the magnesium alkoxide (or suspension containing the magnesium alkoxide) at a low temperature, for example-20 ℃ to 0 ℃. The desired reaction between the transition metal halide and the magnesium alkoxide will occur at low temperatures, but it is preferred that the mixture comprising the transition metal halide and the magnesium alkoxide is heated (e.g. up to 110 ℃) to complete the reaction.

The process of the invention involves the following step (ii): the solid reaction product is contacted with an internal donor and a modifier to provide a procatalyst suitable for olefin polymerization. The procatalyst includes a transition metal supported on a magnesium halide based support, as well as an internal donor and modifier. Step (ii) may comprise carrying out step (i) at least partly in the presence of an internal donor, and optionally at least partly in the presence of a modifying agent. Thus, in this embodiment, the reaction of the halide of the transition metal with the magnesium alkoxide is carried out at least in part in the presence of the internal donor and at least in part in the presence of the modifier. The internal donor and modifier can each be added to the reaction mixture comprising the magnesium alkoxide (e.g., a suspension comprising the magnesium alkoxide) over a wide temperature range (e.g., -20 ℃ to 110 ℃). The internal donor and modifier are each added independently, for example they may be added simultaneously or sequentially. The internal donor and/or modifier may be added to the reaction mixture containing the magnesium alkoxide (e.g., the suspension containing the magnesium alkoxide) prior to the addition of the transition metal halide. In this case, the internal donor and/or modifier will be present during the reaction of the transition metal and magnesium alkoxide. Likewise, the internal donor and/or modifier may be added to the reaction mixture containing the magnesium alkoxide (e.g., a suspension containing the magnesium alkoxide) and the transition metal halide, i.e., after the transition metal halide has been added. For example, the internal donor and/or modifier can be added during heating of the reaction mixture. In this case, the internal donor and/or modifier is added to the mixture before the reaction of the transition metal and the magnesium alkoxide is completed. Thus, the reaction of step (i) is carried out at least partly in the presence of an internal donor and/or at least partly in the presence of a modifier. Alternatively, the modifier may be added after the reaction of step (i) is complete. In one embodiment, step (i) is carried out at least in part in the presence of an internal donor and at least in part in the presence of a modifying agent. In one embodiment, step (i) is carried out at least in part in the presence of an internal donor and at least in part in the presence of a modifying agent, and the modifying agent is contacted with the solid reaction product after completion of the reaction of step (i).

Preferably, the step of contacting the halide of the transition metal and the magnesium alkoxide to react them to form a solid reaction product comprising the transition metal supported on a magnesium halide-based support is carried out at least in part in the presence of an internal donor. The internal donor may be added to the reaction mixture containing the magnesium alkoxide, either before or after the addition of the transition metal halide. The internal donor is added to the mixture before the reaction of the transition metal and the magnesium alkoxide is complete. The modifier may be added to the reaction mixture before or after the addition of the transition metal halide. The modifier may be added to the reaction after completion of the reaction of the transition metal and the magnesium alkoxide.

The process of the present invention provides a solid procatalyst comprising a transition metal, a halogen, magnesium, an internal donor and a modifier. In one embodiment, the activity of the procatalyst resulting from steps (i) and (ii) above is increased by treatment with a halide of a transition metal. Generally, the solid reaction product comprising the transition metal and the internal modifier and modifier supported on a magnesium halide-based support is washed with a hydrocarbon solvent and then contacted with a transition metal halide in the presence of a hydrocarbon solvent to obtain an activated procatalyst. The activated procatalyst may then be heat treated optionally in the presence or absence of a hydrocarbon solvent. Suitable hydrocarbon solvents are known to those skilled in the art.

Thus, the process of the present invention may comprise contacting the solid reaction product of steps (i) and (ii) described above with a halide of a transition metal. This increases the activity of the procatalyst.

In a further aspect, the present invention provides a procatalyst obtained/obtainable by the process of the first aspect of the invention. This includes all embodiments of the method of the first aspect of the invention described herein. Thus, for example, the present invention provides a procatalyst comprising a transition metal, magnesium, a halogen, a modifier and an internal donor, which is obtained/obtainable by a process comprising the steps of: (i) contacting a halide of a transition metal with a magnesium alkoxide to provide a solid reaction product comprising the transition metal supported on a magnesium halide based support, and (ii) contacting the solid reaction product with an internal donor and a modifier, wherein the modifier has the formula I

Wherein R is₁And R₂Each independently hydrogen or alkyl having 1 to 6 carbon atoms, and R₃、R₄、R₅、R₆And R₇Each independently selected from hydrogen, heteroatoms or hydrocarbyl groups. The transition metal, transition metal halide, halogen, magnesium alkoxide, internal donor and modifier are as described in the process of the first aspect of the invention.

In particular, the morphology of the procatalyst is the same or similar to the morphology of the magnesium alkoxide from which the procatalyst is prepared. The particles of the procatalyst may be spherical or spheroidal with a particle size within 10% of the particle size of the magnesium alkoxide. The procatalyst particles may have a smooth surface. In particular, the average ratio (l/w) of the major axis diameter (l) to the minor axis diameter w of the main catalyst particles is 3 or less, preferably 1 to 2, more preferably 1 to 1.5. The average particle size D50 is preferably 5-80 microns, more preferably 10-60 microns, and most preferably 20-40 microns.

The procatalyst of the present invention is useful in combination with an organoaluminum cocatalyst and optionally an external donor for the polymerization of olefin monomers/preparation of polyolefins. Accordingly, the present invention provides a catalyst composition for the polymerisation of olefin monomers comprising: a procatalyst as described above; and a co-catalyst comprising an organoaluminum compound. Accordingly, the present invention provides a catalyst composition for the polymerisation of olefin monomers comprising:

(i) a procatalyst comprising a transition metal, Mg, a halogen, a modifier and an internal donor, wherein the procatalyst is obtainable by: (i) contacting a halide of a transition metal and a magnesium alkoxide to provide a solid reaction product comprising the transition metal supported on a magnesium halide-based support, and (ii) contacting the solid reaction product with an internal donor and a modifier, wherein the modifier has the formula I

Wherein R is₁And R₂Each independently hydrogen or alkyl having 1 to 6 carbon atoms, and R₃、R₄、R₅、R₆And R₇Each independently selected from hydrogen, heteroatoms or hydrocarbyl groups; and

(ii) a co-catalyst comprising an organoaluminum compound.

The catalyst composition may be free of any phthalate.

The cocatalyst comprises an organoaluminum compound. The cocatalyst may be an organoaluminum compound. Typically, the organoaluminum compound is an alkylaluminum compound. The alkyl groups present in the alkylaluminum compounds can be linear or branched. Each of the alkyl groups in the alkyl aluminum compound may independently be a C1 to C8 alkyl group, or a C2 to C6 alkyl group. Preferred organoaluminum compounds include trialkylaluminums such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum and mixtures thereof. Triethylaluminium is preferred.

The cocatalyst is preferably used in excess with respect to the transition metal, for example titanium. Preferably, the molar ratio of aluminum in the co-catalyst to the transition metal, e.g., titanium, in the catalyst composition is from 1 to 500, or from 2 to 200.

Typically, in use, the procatalyst is contacted with the organoaluminum (cocatalyst) compound shortly before the resulting catalyst composition is used in a polymerization reaction. The purpose of the co-catalyst is to activate the procatalyst so that the procatalyst is active for polymerization. Thus, in another aspect, the present invention provides a process for preparing a catalyst composition for polymerizing olefin monomers comprising contacting a procatalyst of the present invention with an organoaluminum compound. The process may comprise the step of preparing the procatalyst as described above prior to contacting the procatalyst with the organoaluminum compound.

The catalyst composition may also include an external donor. In use, the external donor is added to the procatalyst simultaneously with the organoaluminum cocatalyst. Examples of external electron donor compounds used in the polymerization herein include carboxylic acid esters, ketones, ethers, alcohols, lactones, organophosphorus, and silicon compounds. The external donor may be an alkoxysilane. Preferred external donor compounds are organosilicon compounds, such as dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, methylcyclohexyldimethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane. An exemplary external donor is dicyclopentyldimethoxysilane.

Thus, the procatalyst of the present invention may be used to prepare a catalyst composition suitable for polymerizing olefin monomers by contacting the procatalyst of the present invention with an organoaluminum compound and optionally an external donor.

In another aspect, the present invention provides the use of the procatalyst of the invention for polymerizing olefin monomers. Accordingly, the present invention provides the use of a procatalyst as described herein for polymerizing olefin monomers. In particular, the present invention provides the use of the procatalyst of the present invention in the polymerization of olefin monomers to produce polypropylene of high tacticity. For example, the procatalyst may be used to prepare polypropylene having a mmmm content of at least 95%.

Thus in another aspect, the present invention provides a process for preparing a polyolefin comprising polymerizing an olefin monomer in the presence of a catalyst composition as described herein (i.e., a catalyst composition comprising a procatalyst of the present invention, a cocatalyst comprising an organoaluminum compound, and optionally an external donor).

The process may be continuous, semi-continuous or batch, but it is preferably a continuous process. Preferably, the polymerization takes place in a bulk reactor, i.e. it is a bulk polymerization.

The polymerization can be carried out in a conventional manner using conventional conditions.

Preferably, the homopolymerization of propylene takes place in a bulk reactor, i.e. is a bulk polymerization. Optionally, the bulk polymerization is carried out in several reactors (e.g., 1, 2, or 3 reactors). The conditions in each reactor may be the same or different.

Optionally, the process may also include a prepolymerization step prior to the first polymerization step. Any prepolymerization step is carried out in a conventional manner.

The polymerization of the propylene homopolymer is preferably carried out at a temperature of from 65 to 80 ℃ and more preferably about 70 ℃. Preferably, the polymerization is carried out at a pressure of from 0.1 to 4.5MPa, more preferably from 2.9 to 4.2MPa, and still more preferably from 3.3 to 4.2 MPa. Preferably, the polymerization time is from 5 to 240 minutes, more preferably from 30 to 130 minutes, and still more preferably from 40 to 80 minutes. Hydrogen may be added to control the molar mass in a manner known in the art.

The polymerization to prepare the impact copolymer polypropylene typically involves a multistage process. Each stage may be carried out in the same reactor or in separate reactors. The process may be continuous, semi-continuous or batch, but is preferably a continuous process. A preferred process for preparing the impact copolymer polypropylene of the present invention comprises (e.g., consists essentially of): (i) polymerizing propylene and optionally olefin monomers to obtain a propylene homopolymer or copolymer matrix; and (ii) polymerising propylene and ethylene in the presence of a propylene homo-or copolymer matrix to obtain an ethylene-propylene rubber phase dispersed in the propylene homo-or copolymer matrix.

The polymerization of the ethylene-propylene rubber phase is preferably carried out at a temperature of from 65 to 80 ℃ and more preferably about 70 ℃. Preferably, the polymerization is carried out at a pressure of from 0.1 to 2.2MPa, more preferably from 1 to 1.6MPa and still more preferably from 1 to 1.3 MPa.

Typically, the olefin monomer is selected from the group consisting of ethylene, propylene, butylene, and isoprene monomers. Mixtures of two or more different olefin monomers can be used to produce the copolymers. Preferably, the olefin monomer comprises a propylene monomer.

Typically, the polyolefin is selected from the group consisting of polyethylene, polypropylene, polybutylene and polyisoprene. Preferably, the polyolefin is polypropylene. Preferably, the polyolefin is a propylene homopolymer. In one embodiment, the polyolefin is a copolymer. The polyolefin may be an impact copolymer polypropylene.

Further advantages and features of the invention are illustrated by the examples in the following sections.

Examples

Material

All starting materials are commercially available.

Measuring method

The following describes the performance testing of the catalyst composition/system of the present invention. The test methods and equipment employed are conventional and are not intended to limit the scope of the present invention.

The amounts of Internal Donor (ID) and modifier (M) in the procatalyst were measured using H-NMR.

The amounts of Ti and Mg in the main catalyst were measured using ICP (inductively coupled plasma) mass spectrometry.

Unless otherwise stated, the productivity (kg polymer/g catalyst) used in the present specification means: kilograms of polymer produced per gram of procatalyst consumed in the polymerization reactor per hour. For polypropylene, the unit of productivity is referred to as kgPP/gCat.

Melt Flow Rate (MFR) was determined according to ASTM D1238-13 at 230 ℃ under 2.16 kg. 2.16kg is the load used when measuring MFR.

Xylene Solubles (XS) was measured according to ASTM D5492-10 (Standard test method for determining xylene solubles in propylene plastics). As used herein, the terms "xylene solubles", "XS" and "xylene soluble fraction" are interchangeable. The xylene soluble fraction is roughly related to the amorphous (random) fraction in polypropylene.

mmmm and mrrm by using Bruker AsOf cend 500NMR spectrometer¹³C-NMR spectroscopy (¹³C resonance frequency 100.4 MHz). mmmm represents the degree of isotacticity of polypropylene, and mrrm represents the degree of atactic of polypropylene. These are given in mol% of polypropylene and represent the integrated area of a particular peak divided by the integrated area of the total peak. mmmm and mrrm according to "with MgCl₂High resolution of polypropylene prepared with supported Ziegler-Natta catalyst¹³C NMR configurational analysis, 1. "model" System MgCl₂/TiCl₄-2, 6-dimethylpyridine/Al (C)₂H₅)₃", Busico et al, Macromolecules 1999, 32, 4173-4182".

The particle characteristics are defined by D10, D50, and D90, which are particle sizes at 10%, 50%, and 90% on a cumulative number basis, respectively. In this context, the term "size" is equivalent to a diameter. The measured diameter is the maximum diameter of the particle. These values were obtained from SEM images of over 500 particles using image processing software.

The average ratio (l/w) of the major axis diameter (l) to the minor axis diameter (w) of the magnesium alkoxide is obtained by photographing magnesium alkoxide particles with a scanning electron microscope at a magnification showing 500 or more particles on one screen. After randomly extracting 500 particles from the photographed particles and measuring the major axis diameter (l) and the minor axis diameter (w) of each particle with image analysis processing software, the ratio of l/w was calculated. The average l/w is the average of the l/w values measured for 500 particles.

Examples 1 and 2

Synthesis of solid Main catalyst component-Main catalyst 1

The magnesium ethoxide used to prepare the solid procatalyst had a D50 of 35 microns and an average ratio (l/w) of major axis diameter (l) to minor axis diameter (w) of 1 to 1.5.

The flask, having an internal volume of 1000mL and equipped with an overhead stirrer, was thoroughly purged with anhydrous nitrogen. To the flask were introduced 10g of magnesium ethoxide, 60mL of toluene, 40mL of titanium tetrachloride, 3.6g of 9, 9-bis (methoxymethyl) fluorene, and 0.64g of N, N-dimethylbenzamide to form a suspension at-5 ℃. The components were added under a stream of anhydrous nitrogen. After all the components were added, all the valves of the reactor were closed to maintain the pressure in the reactor slightly above atmospheric. The temperature of the suspension was gradually raised to 110 ℃ and the suspension was kept at this temperature for 2 hours with stirring. At this point, the reaction was complete and the resulting solid was washed four times with 100mL of toluene at 100 ℃. Then, 50mL of toluene and 20mL of titanium tetrachloride were added to the flask containing the resulting solid. The solid was heated to 110 ℃ and stirred at this temperature for 30 minutes. The resulting solid was allowed to settle and the supernatant removed. The above procedure was repeated twice, and then the solid was washed six times with 100mL of toluene at 100 ℃. The solid was further washed twice with 100mL of hexane at 70 ℃ and a solid procatalyst was obtained by solid-liquid separation. The amounts of magnesium, 9-bis (methoxymethyl) fluorene and N, N-dimethylbenzamide present in the procatalyst were determined according to the above method.

Bulk polymerization of propylene

The performance of the procatalyst in propylene polymerization was tested in a 2.4L reactor. The reactor was preheated at 100 ℃ for 2 hours under a nitrogen flow to remove contaminating moisture and oxygen. Thereafter, the reactor was cooled to 25 ℃ and 1000g of liquid propylene was added to the reactor. The solid procatalyst (procatalyst 1) was precontacted with triethylaluminum (in 1M hexane solution) with (example 1) or without (example 2) an external electron donor, dicyclopentyldimethoxysilane (D donor), in a separate 10mL stainless steel pot. For example 1, the Ti/Al molar ratio was 1/200. For example 2, the Ti/Al/Si molar ratio was 1/200/20. The mixture in a 10mL stainless steel tank was flushed into the reactor using high pressure nitrogen. As a prepolymerization step, the reactor was kept at 25 ℃ for 10 minutes. Thereafter, the reaction temperature was raised to 70 ℃ and maintained at that temperature for 1 hour to complete the polymerization. Use of¹³The Melt Flow Rate (MFR), xylene solubles (XS%) and mmmm% of the polymer were evaluated by C NMR. The productivity of the catalyst was measured. The results are reported in table 1.

Example 3 and example 4

Synthesis of solid Main catalyst component-Main catalyst 2

Solid procatalyst preparation of procatalyst 2 was carried out in the same manner as procatalyst 1 except that 1.1g of N, N-dimethylbenzamide was used instead of 0.64g of N, N-dimethylbenzamide.

Bulk polymerization of propylene

Bulk polymerization of propylene of example 3 and example 4 was carried out in the same manner as described in example 1 and example 2, respectively, except that the procatalyst 2 was used instead of the procatalyst 1. The solid procatalyst, procatalyst 2, was precontacted with triethylaluminum (in 1M hexane solution) with (example 3) or without (example 4) an external electron donor, dicyclopentyldimethoxysilane (D donor). For example 3, the Ti/Al molar ratio was 1/200. For example 4, the molar ratio Ti/Al/Si was 1/200/20. The results are summarized in table 1.

Example 5

Synthesis of solid Main catalyst component-Main catalyst 3

Solid procatalyst preparation was carried out in the same manner as procatalyst 1 except that 3g of 9, 9-bis (methoxymethyl) fluorene was used instead of 3.6g of 9, 9-bis (methoxymethyl) fluorene and 2.6g of N, N-dimethylbenzamide was used instead of 0.64g of N, N-dimethylbenzamide.

Bulk polymerization of propylene

Bulk polymerization of propylene was carried out in the same manner as described in example 1, except that the procatalyst 3 was used instead of the procatalyst 1. Polymerization was performed using an external electron donor, dicyclopentyldimethoxysilane (D donor). The molar ratio of Ti/Al/Si was 1/200/20.

Example 6

Synthesis of solid Main catalyst component-Main catalyst 4

Solid procatalyst preparation was carried out in the same manner as procatalyst 1 except that 2g of 9, 9-bis (methoxymethyl) fluorene was used instead of 3.6g of 9, 9-bis (methoxymethyl) fluorene and 2g of N, N-dimethylbenzamide was used instead of 0.64g of N, N-dimethylbenzamide.

Bulk polymerization of propylene

Bulk polymerization of propylene was carried out in the same manner as described in example 1, except that the procatalyst 4 was used instead of the procatalyst 1. Polymerization was performed using an external electron donor, dicyclopentyldimethoxysilane (D donor). The molar ratio of Ti/Al/Si was 1/200/20.

Comparative example 1 and comparative example 2

Synthesis of solid Main catalyst component-comparative Main catalyst 1

The solid procatalyst preparation was carried out in the same manner as the procatalyst 1, except that N, N-dimethylbenzamide was not introduced into the reactor to prepare the solid catalyst component.

Bulk polymerization of propylene

Bulk polymerization of propylene of comparative examples 1 and 2 was carried out in the same manner as described in examples 1 and 2, respectively, except that comparative procatalyst 1 was used instead of procatalyst 1. The results are summarized in table 1.

The results of table 1 show that the procatalyst of the present invention prepared using N, N-dimethylbenzamide as the modifier and 9, 9-bis (methoxymethyl) fluorene as the internal donor shows excellent stereoselectivity when used to polymerize propylene. In fact, the results show that the use of modifiers and internal donors in the procatalyst of the invention can increase the isotacticity of the polypropylene produced using the procatalyst. In particular, due to the use of the benzamide modifier in the procatalyst, a significant increase in the isotacticity of the produced polypropylene is observed, while the productivity and MFR remain at high values.

For example, as can be seen from Table 1, the xylene soluble fraction dropped from 8.49 wt% for comparative example 1 to 2.47 wt% for example 1 and 2.15 wt% for example 3. This correlates to a 0 increase in the N, N-dimethylformamide modifier loading of the catalyst of comparative example 1, with an M/ID value of 0.059 for the procatalyst of example 1 and 0.095 for the procatalyst of example 3. The results also show that the increase in isotacticity of polypropylene is not due to the use of an external donor in the polymerization reaction. Even when an external donor was used, an increase in isotacticity was observed, which could be attributed to the N, N-dimethylbenzamide modifier. The xylene soluble fraction dropped from 3.31 wt% for comparative example 2 to 1.95 wt% for example 2 and 1.83 wt% for example 4. This correlates to a 0 increase in the N, N-dimethyl benzamide modifier loading of the procatalyst of comparative example 2, with an M/ID value of 0.059 for the procatalyst of example 2 and 0.095 for the procatalyst of example 4.

In contrast, for the procatalyst of example 6, the amount of N, N-dimethylbenzamide modifier was further increased to obtain an M/ID value of 0.441, resulting in lower isotacticity. The xylene soluble fraction increased to 2.79 wt%. Without wishing to be bound by any theory, fine particles were found in the polymer, which are believed to be caused by a portion of the magnesium alkoxide carrier dissolved in N, N-dimethylbenzamide.

The present invention therefore relates to the development of a ziegler-natta procatalyst which has a diether as internal donor and can be used to obtain highly isotactic polypropylene. In particular, it has been found that N, N-dimethylbenzamide can be used to improve and optimize the isotacticity obtained, while the catalyst productivity and MFR remain at high values for the diether-based main catalyst.

Claims

1. A process for preparing a procatalyst comprising a transition metal, Mg, a halogen, a modifier and an internal donor, wherein the process comprises (I) contacting a halide of a transition metal and a magnesium alkoxide to provide a solid reaction product comprising a transition metal supported on a magnesium halide based support, and (ii) contacting the solid reaction product with the internal donor and the modifier, wherein the modifier has the formula (I)

2. A process according to claim 1, wherein the halide of the transition metal is contacted with the magnesium alkoxide at least in part in the presence of the internal donor, and optionally at least in part in the presence of the modifier, to provide a solid reaction product.

3. The method according to claim 1 or claim 2, wherein the method comprises the further step of: (iii) contacting the solid reaction product obtained from (i) and (ii) comprising the internal donor and the modifier with a halide of the transition metal.

4. The method of any preceding claim, wherein the magnesium alkoxide comprises particles having an average ratio (l/w) of major axis diameter (l) to minor axis diameter (w) of 3 or less.

5. The method of any one of the preceding claims, wherein the magnesium alkoxide comprises particles having an average particle size, D50, of from 1 micron to 100 microns or from 5 microns to 80 microns.

6. The process of any one of the preceding claims, wherein the magnesium alkoxide has the formula MgOR₁₂OR₁₃Wherein R is₁₂And R₁₃Independently a hydrocarbyl group containing 1 to 6 carbon atoms.

7. The method of any one of the preceding claims, wherein the transition metal is selected from titanium, chromium, hafnium, zirconium, and vanadium, and/or the halide is selected from chloride, bromide, and iodide.

8. The process of any one of the preceding claims, wherein the halide of the transition metal is titanium chloride.

9. The method of any one of the preceding claims, wherein the internal donor is a diether compound.

10. The process of any preceding claim, wherein the amounts of internal donor and modifier used are selected to provide a molar ratio of modifier of formula (I) to internal donor of from 0.01 to 0.5 or from 0.04 to 0.50 in the procatalyst.

11. A procatalyst comprising a transition metal, Mg, a halogen, a modifier and an internal donor, the procatalyst obtained or obtainable by the process of any one of claims 1 to 10.

12. The procatalyst of claim 11, wherein the catalyst comprises particles having an average particle size D50 from 1 micron to 100 microns or from 5 microns to 80 microns.

13. The procatalyst of claim 11 or claim 12, wherein the molar ratio of the modifier of formula (I) to internal donor in the procatalyst is from 0.04 to 0.50, from 0.04 to 0.18 or 0.17, from 0.04 to 0.12, or from 0.05 to 0.10, or from 0.01 to 0.5.

14. The procatalyst of any of claims 11-13, wherein the modifier is present in an amount of 0.25 wt% to 2.0 wt% based on the total weight of the procatalyst and/or the internal donor is present in an amount of 15 wt% to 25 wt% based on the total weight of the procatalyst; alternatively, the modifier is present in an amount of 0.1 wt% to 2.0 wt%, based on the total weight of the procatalyst, and/or the internal donor is present in an amount of 15 wt% to 28 wt%, based on the total weight of the procatalyst.

15. The procatalyst of any one of claims 11-14, wherein the magnesium alkoxide is magnesium ethoxide, the modifier is N, N-dimethylbenzamide, the internal donor is 9, 9-bis (methoxymethyl) fluorene, and the molar ratio of modifier to internal donor is 0.05 to 0.10.

16. A catalyst composition for polymerization of polyolefins, the catalyst composition comprising: the procatalyst of any of claims 11-15; and a co-catalyst, wherein the co-catalyst comprises an organoaluminum compound.

17. The catalyst composition of claim 16, wherein the organoaluminum compound is selected from trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, and methyldiethylaluminum.

18. The catalyst composition of claim 16 or claim 17, further comprising an external donor, preferably selected from the group consisting of carboxylic acid esters, ketones, ethers, alcohols, lactones, and organophosphorus and silicon compounds.

19. The catalyst composition of any one of claims 16-18, wherein the procatalyst is the procatalyst of claim 15, the organoaluminum compound is a trialkylaluminum, and wherein the composition includes dicyclopentyldimethoxysilane.

20. Use of a procatalyst according to any of claims 11-15 or a catalyst composition according to any of claims 16-19 for polymerizing olefin monomers.

21. A process for preparing a polyolefin comprising polymerizing an olefin monomer in the presence of the catalyst composition of any one of claims 16 to 19.

22. The use of claim 20 or the method of claim 21, wherein the olefin monomer comprises a propylene monomer.

23. The method of claim 21, wherein the polyolefin is polypropylene or impact copolymer polypropylene.