ES2644136T3

Sterically demanding dialkoxydialkylsilanes as external donors for ziegler catalysts for the polymerization of propylene

Abstract

A process for polymerizing propylene, the process comprising contacting, in a propylene gas phase polymerization reactor, and optionally one or more comonomers, with a catalyst system comprising a Ziegler-Natta catalyst, and an external electron donor system that comprises di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane to produce a propylene polymer having a molecular weight distribution in the range of 4 to less than 5, measured by dynamic oscillatory scanning as described in the description.

Term

6.7 yearsto projected expiry

Projected expiry 14 June 2033, counted from filing; an application has no term until it is granted.

9 claims: 1 independent, 8 dependent

1
ES 2 644 136 T3 REIVINDICACIONES 1. Un procedimiento para polimerizar propileno, comprendiendo el procedimiento poner en contacto, en un reactor de polimerización en fase gaseosa propileno, y opcionalmente uno o más comonómeros, con un sistema catalizador que comprende un catalizador Ziegler-Natta, y un sistema donador de electrones externo que comprende di(biciclo [2.2.1] heptan-2-il) dimetoxisilano para producir un polímero de propileno que tiene una distribución de pesos moleculares en el intervalo de 4 a menos de 5, medido por barrido oscilatorio dinámico como se describe en la descripción.
2
El procedimiento de acuerdo con la reivindicación 1, en el que el di(biciclo[2.2.1]heptan-2-il)dimetoxisilano comprende una mezcla de estereoisómeros.
3
El procedimiento de acuerdo con la reivindicación 1 o la reivindicación 3, en el que el sistema de donador de electrones externo comprende además al menos un donador de electrones externo seleccionado del grupo que consiste en silanos, éteres, ésteres o aminas impedidas.
4
El procedimiento de acuerdo con una cualquiera de las reivindicaciones 1a 3, en el que el sistema donador de electrones externo comprende además al menos un donador de electrones externo seleccionado del grupo que consiste en dimetildimetoxisilano, metiltrimetoxisilano, tetrametoxisilano o diciclopentildimetoxisilano.
5
El procedimiento de acuerdo con una cualquiera de las reivindicaciones 1a 4, en el que el polímero de propileno tiene una distribución de pesos moleculares en el intervalo de 4 a menos de 4,85, medido por barrido oscilatorio dinámico como se describe en la descripción.
6
El procedimiento de acuerdo con una cualquiera de las reivindicaciones 1a 5, en el que el polímero de propileno tiene un MFR menor de 10 dg/min y solubles en xileno igual o mayor que 1% en peso, ambos determinados como se describe en la descripción.
7
El procedimiento de acuerdo con una cualquiera de las reivindicaciones 1a 5, en el que el polímero de propileno tiene un MFR menor de 10 dg/min y solubles en xileno igual o mayor que 1,5% en peso, ambos determinados como se describe en la descripción.
8
El procedimiento de acuerdo con una cualquiera de las reivindicaciones 1 a 7, que comprende adicionalmente mezclar di(biciclo[2.2.1]heptan-2-il)dimetoxisilano con el catalizador Ziegler-Natta y un cocatalizador para formar el sistema catalizador.
9
El procedimiento de acuerdo con una cualquiera de las reivindicaciones 1a 8, en el que el comonómero comprende al menos uno de etileno, buteno, penteno, hexeno, y octeno.

Independent claims9

158 paragraphs in 8 sections, as filed

ES 2 644 136 T3

DESCRIPTION

Sterically demanding dialkoxydialkylsilanes as external donors for Ziegler catalysts for propylene polymerization

Field of the invention

The embodiments described herein generally refer to the polymerization of propylene by Ziegler-Natta catalysis with an external donor system. More specifically, the embodiments described herein relate to dialkoxydialkylsilanes with sterically demanding alkyl substituents, synthesis thereof, and use thereof in the polymerization of propylene.

Background

External donors are used in conjunction with Ziegler catalysts in propylene polymerization to influence the properties of the final product. For example, external donors can be used to influence or control molecular weight (Mn, Mw, Mz, MWD), tacticity, the amount of xylene soluble material in the polymer, and other product parameters.

An example of an external donor used in propylene polymerization is silanes. For example, patent document US20110152424 describes the use of an electron donor system of methyl (cyclohexyl) dimethoxysilane (donor C). Other dialkoxydialkylsilane compounds have also been used as external donors such as diisopropyldimethoxysilane (donor P, patent documents EP0850889 and US4829038) isobutyl (isopropyl) dimethoxysilane (BUPS, patent documents EP0850889 and US4829038) and dicyclopentyldimethoxysilane (donor US patent D9049499) and dicyclopentyldimethoxysilane (donor patent US D904949). US5438110) (See, figure below).

Qz 4 / Y --OMeO OMe MeO OMe MeO OMe MeO OMe

DonorC BUPS DonorP DonorD

Donor C is known in the art to produce a considerable amount of xylene soluble (XS). Allows you to adjust the XS from about 1 to 5% by weight due to a moderate silane response. As used herein, the term "silane response" refers to the response of XS to varying amounts of silane. It is represented by the m (silane) -XS graph (Figure 3]. Those skilled in the art will understand, that a pronounced silane response does not allow for reliable and consistent XS production on an industrial scale. Therefore, a smoother response as seen in donor C it is beneficial.

In the art, hydrogen is used to control the melt flow index (MFR) of the polymer. In addition to MFR, it also influences the productivity of the catalyst system. Therefore, the productivity of a given system must be considered in relation to the produced MFR. With donor C, very low productivities are observed at a low MFR.

Bulky silanes, such as BUPS, donor P, and donor D, offer good activities at low MFR. However, this group of silanes produces very low XS (<1). Combined with a pronounced silane response (Figure 3), the XS cannot be reliably adjusted using these donors.

Therefore, there remains a need for catalyst and donor systems that produce low MFR and high XS polypropylene with good productivities. Such polymers exhibit high stiffness combined with good processability in applications such as pipe, sheet, raffia, film, blow molding, injection, stretch blow molding, or thermoforming.

Furthermore, the synthesis of bulky silanes is often difficult and expensive. For example, BUPS is synthesized from expensive organometallic reagents. The popular donor D can be provided via the most economical hydrosilylation method, but additional activators need to be used (eg EP0602922).

Therefore, there remains a need for easy and inexpensive methods to obtain bulky silanes.

Bulky polycyclic alkyl substituents, such as bicyclo [2.2.1] heptan-2-yl derivatives, have previously been used in dialkoxydialkylsilanes. Bicyclo [2.2.1] heptan-2-yldimethoxy (methyl) silane (BDMMS) and bicyclo [2.2.1] heptan-2-yltrimethoxysilane (BTMS) have been described in JP 2521676 and EP0299712.

ES 2 644 136 T3

Compendium of the invention

Certain dialkoxydialkylsilanes with sterically demanding alkyl substituents have been found to allow efficient production of polypropylenes having a particularly wide range of MFR-XS combinations. Such bulky external donors were surprisingly found to allow good productivity in domains that are difficult to access with state-of-the-art silanes, ie polymers that combine low MFR with high XS (xylene soluble).

In a first aspect, the embodiments described herein relate to a process for polymerizing propylene, the process comprising contacting, in a gas phase polymerization reactor, propylene and optionally one or more comonomers with a catalyst system comprising a Ziegler-Natta catalyst and an external electron donor system comprising di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane to produce a propylene polymer having a distribution of molecular weights in the range of 4 to less than 5. In some embodiments, the external donor system can also include at least one external donor selected from the group consisting of dimethyldimethoxysilane, methyltrimethoxysilane, tetramethoxysilane, or dicyclopentyldimethoxysilane. Such polymers can be used for pipe, foil, raffia, film, blow molding, injection molding, stretch blow molding, or thermoforming applications. In some embodiments, the catalyst systems can be used to produce a propylene polymer having an MFR of less than 10 dg / min and soluble in xylene equal to or greater than 1% by weight.

Other aspects and advantages will be apparent from the following description and the appended claims.

Brief description of the drawings

Figure 1 illustrates a 1H-NMR spectrum of di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane (DBDMS).

Figure 2 illustrates a 13C-NMR spectrum of DBDMS.

Figure 3 shows a comparison of the silane response of donor C, donor D and DBDMS.

Detailed description

In one aspect, the embodiments described herein generally refer to the polymerization of propylene by Ziegler-Natta catalysis with an external donor system. More specifically, the embodiments described herein relate to dialkoxydialkylsilanes with sterically demanding alkyl substituents, wherein the dialkoxydialkylsilanes comprise di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane, syntheses thereof, and uses of the same in the polymerization of propylene.

As used herein, sterically demanding alkyl substituents refers to bulky alkyl substituents that, due to their proximity to silicon centers, influence, limit, or adapt the interaction of the external donor, the Ziegler-Natta catalyst, and the propylene or other comonomers during the polymerization process. Examples of bulky substituents can include groups with significant branching, preferably α-branched hydrocarbon groups, cyclic hydrocarbon groups, and others.

According to the present specification, the silane donor is di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane. In other embodiments, the silane donor can include di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane and at least one external donor selected from the group consisting of dimethyldimethoxysilane, methyltrimethoxysilane, tetramethoxysilane, or dicyclopentyldimethoxysilane.

Those skilled in the art will understand that one or more isomers of the examples given are possible.

Silane donors useful in embodiments of the present invention can be synthesized by a hydrosilylation method. Bridged and / or polycyclic alkenes readily react, due to ring tension, with dihydrido silanes in the presence of a hydrosilylation catalyst. As an example, a dialkoxydialkylsilane with sterically demanding alkyl substituents can be formed by a method that includes the following steps: mixing a sterically demanding alkyl substituent with a hydrosilylation catalyst; heating the mixture to a temperature in the range of about 40 ° C to about 80 ° C; and introducing dihalosilane into the heated mixture to react the dihalosilane with the sterically demanding alkyl substituent to form a dialkoxydialkylsilane with sterically demanding alkyl substituents. The dihalosilane can be introduced at a rate sufficient to maintain a substantially constant internal temperature of the reaction mixture.

Useful catalysts include elements and compounds of rhodium, palladium and, in particular, platinum. The preferred rhodium complexes are RhCl3 / PPh3 (excess), (PPh3) 3RhCl (Wilkinson Catalyst) and (PPh3) 3HRh (CO). Platinum catalysts are, for example, solutions of hexachloroplatinic acid (H2PtCl6,6H2O) in alcohols such as isopropanol (Speier catalyst), olefinic complexes such as Karstedt's catalyst (Pt (ViMe2SiOSiMe2Vi) 3) or phosphine complexes such as ( PPh3) 3PtCl2. Platinum can also be deposited on

ES 2 644 136 T3 solid support materials such as activated carbon, aluminum oxide or silica gel. The preferred hydrosilylation catalyst is hexachloroplatinic acid / isopropanol.

Due to an exothermic energy profile, it is advisable to measure in at least one component during the reaction and thus control the internal temperature. To avoid the danger of accumulation of reaction energy, starting conditions such as temperature preferably allow a spontaneous reaction.

It is understood that bridged bicyclic substituents can be attached to the silicon atom in two ways (ie, endo or exo) and that one or more combinations are possible for the examples given. Furthermore, it is understood that two or more chiral atoms in a molecule will allow the formation of different diastereomers.

Mixtures of such isomers will be useful in the practice of carrying out this invention. For example, mixtures with an isomer distribution that give rise to the NMR spectra of Figures 1 and 2 are preferred. It is understood that the reaction conditions during hydrosilylation, such as the nature of the catalyst, will allow the isomer distribution to be tailored. . The isomers can also be mixed after synthesis.

In addition, mixtures with other known external donors can be used such as silanes (eg tetraethoxysilane, donor D, donor C, BUPS, donor P), ethers (eg 2,2-diisobutyl-1,3-dimethoxypropane), esters (eg, aromatic carboxylic esters), hindered amines, and the like.

Useful catalyst systems for the polymerization of propylene and propylene interpolymers according to the embodiments described in the present invention can be formed by mixing a Ziegler-Natta catalyst, a cocatalyst and the dialkoxydialkylsilanes described above with sterically demanding alkyl substituents. For example, catalyst systems useful for the polymerization of propylene and propylene interpolymers in accordance with the embodiments described in the present invention can be formed by mixing a Ziegler-Natta catalyst, a cocatalyst, and an external electron donor system comprising di (bicyclo [2.2.1] heptan2-yl) dimethoxysilane.

Ziegler catalysts for use in catalyst systems, including titanium-based catalysts, are described or referred to in US4376062, US4379758, US5066737, US7329626, US5639822, US7071137, US7022795, US6831032, US201001069586, US 2009 , WO2010144080, EP0361494, EP0728769, US4861847, US6235854, US6323298, and US 6683017, among others. Ziegler-Natta catalysts are typically magnesium / titanium internal donor complexes, optionally supported on a suitable support such as silica.

Such internal donors can be diether (patent documents EP728769, EP0361494, EP0361493, EP0728724, US6683017), succinate (patent documents EP0125911, EP0263718, EP0086473), malonate (patent documents CN1236372, CN1292800), 1,3-diketone (document CN1105671) and phthalate (patent documents US7329626, US2010069586) among others.

The catalyst systems of the present invention can include an aluminum compound as a cocatalyst. Examples of suitable aluminum compounds include aluminum trialkyls and their derivatives in which an alkyl group is substituted by an alkoxy group or a halogen atom, for example chlorine or bromine. The alkyl groups can be the same or different. The alkyl groups can be straight or branched chain alkyl groups. For example, trialkylaluminum compounds are those in which the alkyl groups each have 1 to 8 carbon atoms, such as trimethylaluminum, triethylaluminum, tri-isobutylaluminum, trioctylaluminum, or methyldiethylaluminum, may be useful in the embodiments described herein. memory.

To prepare the catalyst system, the aluminum compound as the cocatalyst and the dialkoxydialkylsilanes with sterically demanding alkyl substituents can be contacted with the ZieglerNatta catalyst component separately in any order or mixed together, usually at a temperature in the range of about 0 ° C to about 200 ° C, such as from about 20 ° C to about 90 ° C and at a pressure of from about 1 to about 100 bar, such as from about 1 to about 40 bar.

The aluminum compound cocatalyst can be added in an amount such that the atomic ratio of the aluminum compound to the transition metal of the solid catalyst component is in the range of about 10: 1 to about 800: 1, such as about 20: 1 to approximately 200: 1.

The catalyst systems can be used advantageously in the polymerization of alk-1-enes. Suitable alk-1-enes include linear or branched C2-C10 alkenes, in particular C2-C10 linear alkenes such as ethylene, propylene, but-1-ene, pent-1-ene, hex-1-ene, hept-1 -ene, oct-1-ene non-1-ene, dec-1-ene or 4-methylpent-1ene. Mixtures of these alk-1-enes can also be polymerized.

The catalyst systems can be used, for example, in a gas phase polymerization reactor for the production of propylene polymers, both homopolymers of propylene and copolymers of propylene and one or more alk-1-enos with up to 10 carbon atoms. The term copolymers, as used herein, also refers to copolymers in which the additional alk-1-ene having up to 10 carbon atoms

ES 2 644 136 T3 is incorporated randomly. In these copolymers, the comonomer content is generally less than about 15% by weight. The copolymers can also be in the form of so-called block or impact copolymers which generally comprise at least one matrix of a propylene homopolymer or propylene random copolymer containing less than 15% by weight of another alk-1. -ene having up to 10 carbon atoms and a soft phase of a propylene copolymer containing from 10% to 80% by weight of other alk-1-enos having up to 10 carbon atoms. Also, mixtures of comonomers are contemplated, resulting in, for example, propylene terpolymers.

The production of the propylene polymers can be carried out in any gas phase reactor suitable for the polymerization of alk-1-enes, whether batch, semi-continuous or continuous, such as in fluidized bed reactors or reactors of horizontally or vertically agitated powder bed. It will be understood that the polymerization can be carried out in a series of consecutively coupled reactors. The reaction time depends on the chosen reaction conditions. In general, the reaction time is about 0.2 to about 20 hours, usually about 0.5 to about 10 hours.

In general, the polymerization is carried out at a temperature in the range of from about 20 ° C to about 150 ° C, such as from about 50 ° C to about 120 ° C, or from about 60 ° C to about 90 ° C. , and a pressure in the range of about 1 to 100 bars, such as about 15 to about 60 bars, or about 20 to about 45 bars.

The molecular weight of the resulting polymers can be controlled and adjusted over a wide range, by the addition of chain termination inducing or polymer chain transfer agents as commonly used in the polymerization art, such as hydrogen. In addition, an inert solvent, such as toluene or hexane, or an inert gas, such as nitrogen or argon, an antistatic agent, and small amounts of a powdered polymer, for example, polypropylene powder, can be added.

Average molecular weights (by weight) of propylene polymers that can be produced using the catalyst system of the present invention are generally in the range of about 10,000 to 1,000,000 g / mole and melt flow rates are in the range of about 0.1 to 1,000 g / 10 min, preferably about 0.1 to 200 g / 10 min. The melt flow index corresponds to the amount that is pressed for 10 minutes from a test instrument according to ISO 1133 at a temperature of 230 ° C and under a load of 2.16 kg. Certain applications may require molecular weights other than those mentioned above and their inclusion within the scope of the embodiments described herein is contemplated.

The catalyst systems described allow in particular the efficient production of rigid material (low MFR) with improved processability (increased XS and a desirable molecular weight distribution). Although stiffness is an advantageous property of polymers, it also causes problems during processing. Therefore, it is beneficial if the rigid materials contain a significant amount of XS which acts as a lubricant, reduces crystallinity, and therefore supports processing. However, external donors that efficiently produce high molecular weight polymers (= low MFR), such as Donor D, Donor P, or BUPS, also produce low XS (typically below 1% by weight). This XS cannot be reliably adjusted to higher levels due to an abrupt silane response from such donors (see Figure 3). In contrast, donors such as donor C that allow the highest XS adjustment (1-5% by weight) due to a moderate silane response (see Figure 3), are limited in their productivity towards high molecular weights. The described catalyst systems that include an external electron donor system comprising di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane combine for the first time excellent productivities for polymers with low MFR, a molecular weight distribution in the range of about 4 to less than 5, and XS high. Furthermore, the response of silane is even milder than that of donor C (see Figure 3).

Advantageous properties provided by the use of an external electron donor system comprising di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane with low MFR, a molecular weight distribution in the range of about 4 to less than 5 , and high XS, have been found to only result in gas phase polymerizations (bulk polymerization experiments, as described below, resulted in significantly higher MWD). Embodiments herein include a process for polymerizing propylene, said process including: contacting, in a gas phase polymerization reactor, propylene, and optionally one or more comonomers, with a catalytic system comprising a Ziegler-Natta catalyst, and an external electron donor system comprising di (bicyclo [2.2.1 ] heptan-2-yl) dimethoxysilane to produce a propylene polymer having a molecular weight distribution in the range of 4 to less than 5.

In some embodiments, the di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane comprises a mixture of stereoisomers. In other embodiments, the external donor system further comprises at least one external donor selected from the group consisting of hindered silanes, ethers, esters, or amines. In some embodiments, the external donor system can also include at least one external donor selected from the group consisting of dimethyldimethoxysilane, methyltrimethoxysilane, tetramethoxysilane, or dicyclopentyldimethoxysilane.

ES 2 644 136 T3

As noted above, embodiments of the gas phase polymerization process using an external electron donor system comprising di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane, can result in a propylene polymer having a molecular weight distribution in the range of about 4 to less than 5. In other embodiments, the resulting propylene polymer can have a molecular weight distribution in the range of about 4 to less than 4.85.

As also noted above, embodiments of the gas phase polymerization process using an external electron donor system comprising di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane can produce propylene polymers having a low MFR and XS high. In some embodiments, for example, the propylene polymer may have an MFR of less than 10 dg / min and soluble in xylene in an amount equal to or greater than 1% by weight; In other embodiments, the propylene polymer may have an MFR of less than 10 dg / min and soluble in xylene in an amount equal to or greater than 1.5% by weight, 1.75% by weight, or 2% by weight.

The polymers obtainable by using the catalyst systems described in the present invention can be advantageously used in applications such as pipe, sheet, raffia, axially or biaxially oriented film, blow molding, injection molding, stretch blow molding, or thermoforming.

Examples

The invention described herein is illustrated, but not limited, by the following examples and comparative rounds.

Example I: Synthesis of di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane (DBDMS).

A 100 ml round bottom flask with gas inlet and magnetic stir bar is charged with 20.0 g (159 mmol) of bicyclo [2.2.1] heptene and heated to approx. 50 ° C to melt it. 0.6 ml (approximately 0.06 mmol) of a 0.1 M solution of H2PtCl6-xH2O in isopropanol are added. The reaction flask is carefully emptied three times and filled with an atmosphere of dry nitrogen and heated to 60 ° C. With vigorous stirring, the addition of dichlorosilane is started. The dichlorosilane addition is stopped when 12 g of dichlorosilane have been added and stirring is continued.

After purging the reaction flask with dry nitrogen and cooling the reaction mixture to room temperature, the reaction mixture is diluted with 40 ml of diethyl ether. The resulting solution is transferred to a dropping funnel and added to a solution of 25.2 g (319 mmol) of pyridine and 10.2 g (319 mmol) of methanol in 100 ml of diethyl ether. After the addition is complete, the mixture is stirred for another 30 minutes at room temperature. The precipitate is filtered off and the filtrate is washed twice with deionized water and dried over anhydrous sodium or magnesium sulfate. The solvent is removed and the crude product is purified by fractional distillation under high vacuum (bp: 110-112 ° C at 6-10 '2 mbar). Figures 1 and 2 show examples of NMR spectra of the expected compound.

Example II: Polymerization procedure.

The laboratory-scale reactor was equipped with a stirrer capable of gas phase polymerization. The test was carried out using a 5.3 liter reactor with 366 grams of propylene (plus replenishment - see below), 0.3 ml of a 0.1 M solution of silane in heptane (= external donor), 2.5 ml of 1.3 M triethylaluminum (TEAl) in heptane. The amount of hydrogen was adjusted to produce the desired MFR.

The reactants were introduced into the reactor in the following order: After the addition of hydrogen, TEA1 and silane were purged together into the reactor using 183 grams of propylene. Another 183 gram portion of propylene was used to purge the catalyst in the 40 ° C reactor. The reactor was then heated to 75 ° C for 10 minutes and kept at this temperature for 1 hr of polymerization time. The reactor pressure was maintained at 27.6 bar at 75 ° C with addition of make-up propylene on demand and was monitored by means of a mass flow meter.

Catalyst in Example II refers to the solid components of the catalyst systems employed, comprising magnesium / titanium internal donor complexes, optionally supported on a suitable support such as silica. Catalyst A was produced by a method similar to that described in patent document US5639822. It was supported on silica and contained 4.1% by weight of titanium and 8.3% by weight of magnesium. Before use, about 0.02 grams of catalyst powder was immersed in heptane under an inert atmosphere and prepared for injection. Catalyst B was produced by a method similar to that described in patent document US2010069586. This contained 2.0% by weight of titanium and 19.7% by weight of magnesium. Before use, about 0.01 grams of the catalyst powder was immersed in white oil under an inert atmosphere and prepared for injection. Catalyst C was produced by a method similar to that described in patent document US4861847. This contained 1.7% by weight of titanium and 19.8% by weight of magnesium. Before use, about 0.01 grams of the catalyst powder was immersed in white oil under an inert atmosphere and prepared for injection.

ES 2 644 136 T3

The external donors used in Example II were: the non-inventive silanes methyl (cyclohexyl) dimethoxysilane (donor C), diisopropyldimethoxysilane (donor P) isobutyl (isopropyl) dimethoxysilane (BUPS), dicyclopentyldimethoxysilane (donor D), bicyclo [2.2. 1] heptan-2-yl dimethoxy- (methyl) silane (BDMMS), bicyclo [2.2.1] heptan-2-yl trimethoxysilane (BTMS) and as an example of a silane of the invention di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane (DBDMS).

The physical characteristics of the polypropylene polymers produced using the various silanes were determined using the methods described below. The results obtained are summarized in tables 1 to 6.

Activity. The activity results reported throughout this study are based on the polymer produced in grams per gram of catalyst per one hour of polymerization (equivalent to the procedure described above).

Soluble in xylene (% by weight of XS). Xylene soluble materials were measured using the VISCOTEK Flow Injector Polymer Analysis (FIPA) technique which is well known in the industry. VISCOTEK has published an article titled, FIPA for xylene soluble determination of polypropylene and impact copolymers (which can be ordered from the VISCOTEK website, http://www.viscotek.com/applications.aspx) showing that the VISCOTEK FIPA method features a correlation of 0.994 r2 with aSTm method D5492-06 (equivalent to ISO 16152) in the range of 0.3% to 20% soluble in xylene. Therefore, one skilled in the art could reproduce the results of the invention using the VISCOTEK FIPA method or the ASTM method D5492-06. The percent by weight of xylene solubles in the polypropylene is an indication of the stereoregulatory ability of the catalyst - the higher the% by weight of XS, the worse the stereoregulatory ability of the catalyst.

Measurement of melt flow index (MFR). The melt flow index was measured in accordance with ASTM method D 1238-04. For each 5 gram sample of polymer, 0.2 grams of a stabilizer pack was added. The additive package consists of 50% by weight of IRGANOX 1010 and 50% by weight of IRGAFOS 168. Because the polymer is exposed to air at 230 ° C for several minutes during the test, this pack is added to inhibit thermal and oxidative degradation of the polymer. The melt flow index provides information regarding molecular weight: the higher the MFR, the lower the molecular weight of the polymer.

Melting point (Tm). Tm was determined by DSC according to ISO 3146 using a 5 mg polymer sample and applying a first heating stage at a heating rate of 20 ° C / min up to 230 ° C and a retention time of 230 ° C for 10 minutes, followed by a crystallization step with a cooling rate of 20 ° C / min from 200 ° C to -20 ° C with a retention time at -20 ° C of 10 min, followed by a second heating stage at a heating rate of 20 ° C / min at 230 ° C. The melting point obtained is the temperature, at which the enthalpy of the second heating cycle shows the maximum. A METTLER TOLEDO instrument (DSC822e) has been used after indium calibration under the above mentioned measurement conditions.

The molecular weight distribution (MWD) was determined by rheometric measurement, the so-called dynamic oscillatory sweep (DORS). A compression molded disc-shaped sample is loaded between a parallel plate-plate geometry. Measurements were carried out in a crossover frequency range between 0.1 and 400 rad / s. The MWD that was calculated from the crossover modulus as follows: MWD = 105 Pa / Gc, where Gc = dynamic storage modulus (G ') = dynamic loss modulus (G ") at crossover frequency.

Table 1: Polymerization Examples 1-19 with Catalyst A and varying amounts of hydrogen. The examples are grouped according to the silanes used. Silanes are ranked roughly according to their tendency to produce XS (highest first), while the order within a group is based on MFR (lowest first).

<td>Polymer example</td><td>Cat.</td><td>Silaneto)</td><td>Yes [ml]</td><td>H2 [g]</td><td>Activity [kg / gcat]</td><td>MFR [g / 10min]</td><td>XS [% in weigh]</td><td>Tm [° C]</td>

<td> 2</td><td>TO</td><td>BDMMS</td><td> 0,3</td><td> 0,058</td><td> 10,6</td><td> 4,5</td><td> 1,8</td><td> 162.0</td>

<td> 3</td><td>TO</td><td>BDMMS</td><td> 0,3</td><td> 0,109</td><td> 15,5</td><td> 9,3</td><td> 1,3</td><td> 161,8</td>

<td> 4</td><td>TO</td><td>Donor C</td><td> 0,3</td><td> 0,005</td><td> 10,4</td><td> 1,0</td><td> 1,9</td><td> 162,6</td>

<td> 5</td><td>TO</td><td>Donor C</td><td> 0,3</td><td> 0,056</td><td> 11,8</td><td> 4,1</td><td> 1,7</td><td> 163,1</td>

ES 2 644 136 T3

<td> 6</td><td>TO</td><td>Donor C</td><td> 0,3</td><td> 0,200</td><td> 15,2</td><td> 12,6</td><td> 1,4</td><td> 161,4</td>

<td> 7</td><td>TO</td><td>DBDMS</td><td> 0,3</td><td> 0,058</td><td> 11,6</td><td> 0,3</td><td> 1,5</td><td> 164,6</td>

<td> 8</td><td>TO</td><td>DBDMS</td><td> 0,3</td><td> 0,100</td><td> 17,3</td><td> 0,9</td><td> 1,9</td><td> 166,2</td>

<td> 9</td><td>TO</td><td>DBDMS</td><td> 0,3</td><td> 0,405</td><td> 15,3</td><td> 4,3</td><td> 1,7</td><td> 164,7</td>

<td> 10</td><td>TO</td><td>DBDMS</td><td> 0,3</td><td> 0,755</td><td> 14,8</td><td> 12,7</td><td> 1,7</td><td> 164,1</td>

<td> 14</td><td>TO</td><td>Donor P</td><td> 0,3</td><td> 0,050</td><td> 14,8</td><td> 0,7</td><td> 0,8</td><td> 165,3</td>

<td> 15</td><td>TO</td><td>Donor P</td><td> 0,3</td><td> 0,300</td><td> 18,9</td><td> 5,2</td><td> 0,7</td><td> 163,6</td>

<td> 16</td><td>TO</td><td>Donor P</td><td> 0,3</td><td> 0,501</td><td> 19,8</td><td> 12,3</td><td> 0,7</td><td> 163,2</td>

<td> 17</td><td>TO</td><td>Donor D</td><td> 0,3</td><td> 0,058</td><td> 20,5</td><td> 1,1</td><td> 0,4</td><td> 165,2</td>

<td> 18</td><td>TO</td><td>Donor D</td><td> 0,3</td><td> 0,405</td><td> 17,7</td><td> 5,6</td><td> 0,7</td><td> 163,1</td>

<td> 19</td><td>TO</td><td>Donor D</td><td> 0,3</td><td> 0,703</td><td> 23,5</td><td> 11,5</td><td> 0,9</td><td> 163,8</td>

to) Methyl (cyclohexyl) dimethoxysilane (donor C), diisopropyldimethoxysilane (donor P) isobutyl (isopropyl) dimethoxysilane (BUPS), dicyclopentyldimethoxysilane (donor D), bicyclo [2.2.1] heptan-2- ildimethoxy (methyl) silane (BDMMS), bicyclo [2.2.1] heptan-2-yl trimethoxysilane (BTMS) and di (bicyclo [2.2.1] heptan-2-yl) dimethoxysilane (DBDMS).

Therefore, the present inventors have discovered that the external donors described therein, such as DBDMS, produce low MFR polymers (<10) with activity comparable to well-known benchmarks, such as donor D, BUPS and donor P, but with a significantly higher amount of XS. Polymers with similarly high XS and low MFR cannot be obtained with donor C without massive loss of activity.

The silane response of selected donors with Catalyst A is depicted in Figure 3. Polymer examples 20-42 were synthesized according to Example II with 0.05 mL H2, but with varying amounts of external donor. Figure 3 emphasizes the fact that donors such as donor D show a pronounced silane response, making a reliable fit of XS impossible. Donor C allows a much better fit, due to a moderate response. DBDMS shows an even smoother response, allowing reliable industrial process control.

Table 2: Examples of polymerization 43-46 with Catalyst B. The examples are grouped according to the silanes used.

<td>Polymer example</td><td>Cat.</td><td>Silane</td><td>Yes [ml]</td><td>h2[g]</td><td>Activity [kg / gcat]</td><td>MFR [g / 10min]</td><td>XS [% in weigh]</td><td>Tm[° C]</td>

<td> 43</td><td>B</td><td>Donor C</td><td> 0,3</td><td> 0,01</td><td> 21,7</td><td> 1,0</td><td> 1,8</td><td> 160,4</td>

<td> 44</td><td>B</td><td>Donor C</td><td> 0,3</td><td> 0,1</td><td> 32,7</td><td> 6,4</td><td> 1,8</td><td> 161,1</td>

<td> 45</td><td>B</td><td>DBDMS</td><td> 0,3</td><td> 0,1</td><td> 38,7</td><td> 1,5</td><td> 1,8</td><td> 165,2</td>

<td> 46</td><td>B</td><td>DBDMS</td><td> 0,3</td><td> 0,4</td><td> 34,6</td><td> 5,8</td><td> 1,5</td><td> 163,3</td>

The results in Table 2 confirm, that the described advantageous effects of DBDMS are not limited to a specific catalyst.

ES 2 644 136 T3

Table 3: Examples of polymerization 47-50 with Catalyst C. The examples are grouped according to the silanes used.

<td>Polymer example</td><td>Cat.</td><td>Silane</td><td>Yes [ml]</td><td>H2 [g]</td><td>Activity [kg / gcat]</td><td>MFR [g / 10min]</td><td>XS [% in weigh]</td><td>Tm [° C]</td>

<td> 47</td><td>C</td><td>Donor C</td><td> 0,3</td><td> 0,01</td><td> 19,3</td><td> 1,1</td><td> 1,7</td><td> 160,8</td>

<td> 48</td><td>C</td><td>Donor C</td><td> 0,3</td><td> 0,1</td><td> 31,3</td><td> 6,5</td><td> 1,6</td><td> 161,8</td>

<td> 49</td><td>C</td><td>DBDMS</td><td> 0,3</td><td> 0,1</td><td> 35,8</td><td> 1,0</td><td> 1,5</td><td> 163,0</td>

<td> 50</td><td>C</td><td>DBDMS</td><td> 0,3</td><td> 0,4</td><td> 34,2</td><td> 5,3</td><td> 1,6</td><td> 164,3</td>

The results in Table 3 confirm that the described advantageous effects of DBDMS are not limited to a specific catalyst.

Table 4: Low MFR polymerization examples (~ 1)