WO2025254855A1 - Polymerization of propylene-based compositions with enhanced hydrogen response and methods related thereto - Google Patents

Abstract

An olefin polymerization system for increasing melt flow response to hydrogen of resultant polyolefin polymers. The catalyst system for the polymerization of olefin monomers comprising a Ziegler-Natta catalyst in combination with two external donors of a dialkyl diamino silane and tetraethyl orthosilicate.

Description

POLYMERIZATION OF PROPYLENE-BASED COMPOSITIONS WITH

ENHANCED HYDROGEN RESPONSE AND METHODS RELATED THERETO

CROSS REFERECNE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Application 63/656,688 filed June 6, 2024 and titled “POLYMERIZATION OF PROPYLENE-BASED COMPOSITIONS WITH ENHANCED HYDROGEN RESPONSE AND METHODS RELATED THERETO”, the entirety’ of which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present disclosure relates to polyolefin polymerization, and more particularly to compositions and methods for producing polypropylenes and co-monomers thereof having increased hydrogen response.

BACKGROUND

[0003] In the polymerization of olefins such as propylene, catalyst systems comprising magnesium, titanium, halogen, and an electron-donating compound as essential components have been conventionally been known. In addition, a number of methods for polymerizing or copolymerizing olefins in the presence of a catalyst system formed of such solid catalyst components, and further in the presence of an organoaluminum compound, and an organosilane compound have been proposed.

[0004] Among these catalysts for polymenzation of olefins, it has been reported that excellent polymerization activity and stereospecificity are exhibited in a case where a solid titanium catalyst component (solid catalyst component) having an internal electron-donating compound, typical examples of which include a phthalic acid ester, in particular, carried thereon; and an organoaluminum compound and at least one organosilane as a promoter. These catalysts are referred to as Ziegler-Natta catalysts.

[0005] Ziegler-Natta catalysts can suffer from relatively low melt flow capability because they are limited by the concentration of hydrogen achievable during the polymerization process. The concentration of hydrogen itself is limited by its solubility’ in propylene and co-monomers thereof at the temperature and pressure of the polymerization equipment. Moreover, external catalyst donors used to control polypropylene and co-polymers thereof crystallinity also affect response to hydrogen. Hydrogen response influences the molecular weight of the produced polymer, where an increase in hydrogen response produces lower molecular weight polymers and a decrease in hydrogen response produces higher molecular weight polymers. And as molecular weight decreases, so too does the polymers melt flow rate. Polypropylene polymers and co-polymers having a low melt flow can limit the compatibility⁷ of the polypropylene compositions and co-polymers thereof with various manufacturing techniques (e.g., extrusion and high throughput molding techniques).

[0006] Accordingly, a Ziegler-Natta catalyst system for propylene and co-monomers thereof polymerization that is capable of producing polymers that exhibits a high response to hydrogen and thus is characterized by high melt flow, with substantially undiminished crystallinity' as defined by xylene solubles is desirable.

SUMMARY

[0007] In nonlimiting aspects of the present disclosure, a catalyst system is provided for the polymerization of olefin monomers. The catalyst system includes a Ziegler-Natta catalyst, a dialkyl diamino silane external donor, and a tetraethyl orthosilicate (TEOS) external donor.

[0008] In nonlimiting aspects of the present disclosure, a method includes introducing a catalyst system into a reactor, the catalyst system including a Ziegler-Natta catalyst, a dialkyd diamino silane external donor, and a tetraethyl orthosilicate (TEOS) external donor, and feeding olefin monomers into the reaction zone under conditions for polymerization, thereby resulting a polyolefin polymers.

[0009] These and other features and attributes of the disclosed methods for producing pitch compositions having tailored and reproducible properties of the present disclosure and their advantageous applications and/or uses will be apparent from the detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] To assist those of ordinary' skill in the relevant art in making and using the subject matter hereof, reference is made to the appended drawings. The following figures are included to illustrate certain aspects of the disclosure, and should not be viewed as exclusive configurations. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to those skilled in the art and having the benefit of this disclosure. [0011] FIG. 1 shows a chart of MFR for various concentrations of polymerization results according to the present disclosure compared to comparative polymerization results.

[0012] FIG. 2 shows a chart of %XS for various concentrations of polymerization results according to the present disclosure compared to comparative polymerization results.

[0013] FIG. 3 shows a chart of Activity' for various concentrations of polymerization results according to the present disclosure compared to comparative polymerization results.

DETAILED DESCRIPTION

[0014] The present disclosure relates to polyolefin polymerization, and more particularly to compositions and methods for producing polypropylenes and co-monomers thereof having increased hydrogen response.

[0015] There is a need for a composition and methodology for the production of polypropylene compositions and co-monomer compositions thereof having increased melt flow without compromised crystallinity⁷, which will be suitable for one or more particular enduses. The present disclosure provides a methodology that employs compositional details to permit increased melt flow of polypropylene compositions and co-monomers thereof by utilizing a combination of a Ziegler-Natta catalyst and a combination of two external electron donors: a dialkyl diamino silane and tetraethyl orthosilicate (TEOS). In one or more aspects of the present disclosure, the dialkyl diamino silane has the composition of R^SiiNHR²^, as provided below, and the TEOS is present in an amount of 50% by weight (wt.%) to 90 wt.% of the Ziegler-Natta catalyst system; upon polymerization of olefin monomers, the catalyst system exhibits a level of xylene solubles less than about 3 wt.% and a melt flow rate of greater than 700 grams per gram per hour. In one or more aspects, the combined ratio of the dialkyl diamino silane and TEOS external donors to the titanium (Ti) in the Ziegler-Natta catalyst is in the range of about 8 to 50 molar ratio, encompassing any value and subset therebetween, such as about 10 to 50 molar ratio, or about 20 to 50 molar ratio, or about 30 to 50 molar ratio, or about 40 to 50 molar ratio, or about 50 molar ratio.

DEFINITIONS AND TEST METHODS

[0016] All numerical values within the detailed description and the claims herein are modified by “about” or “approximately” with respect to the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art. Unless otherwise indicated, ambient temperature (room temperature or “RT”) is about 25°C. [0017] As used in the present disclosure and claims, the singular forms “a,” "an." and

“the” include plural forms unless the context clearly dictates otherwise.

[0018] The term “and/or” as used in a phrase such as “A and/or B” herein is intended to include “A and B,” “A or B,” “A,” and “B.”

[0019] For the purposes of the present disclosure and the claims thereto, the following definitions shall be used.

[0020] As used herein, the term “catalyst system,” and grammatical variants thereof, refers to a Ziegler-Natta catalyst in combination with the at least two external donors described herein: a di al ky 1 diamino silane and tetraethyl orthosilicate (TEOS) to effect polymerization of olefins to polyolefins. The term “Ziegler-Natta catalyst” may be used interchangeably with simply “catalyst,” and may be comprised of a solid and supported catalyst from titanium and a co-catalyst, usually of aluminum.

[0021] The term “external donor,” and grammatical variants thereof, refers to act as stereoselective control agents to control the amount of atactic or non-stereoregular polymer produced during polymerization in the presence of a Ziegler-Natta catalyst. [0022] As used herein, a “polymer,” and grammatical variants thereof, is comprised of polymerized olefin monomers, such as polymerized polypropylene homopolymers of propylene monomer (propylene-derived units) or co-monomers of polypropylene and additional olefin monomers, such as ethylene.

[0023] A “reactor,” and grammatical variants thereof, as used herein, is any type of vessel or containment device in any configuration of one or more reactors, and/or one or more reaction zones, wherein a similar polymer is produced; however, two or more reactors that are fluidly connected with one another can each produce separate polymers.

[0024] As used herein, the term “melt flow rate” or “MFR,” and grammatical variants thereof, is the number of grams extruded in 10 minutes under the action of a standard load and is an inverse measure of viscosity. A high MFR implies low viscosity and low MFR implies high viscosity. In addition, polymers are shear thinning, which means that their resistance to flow decreases as the shear rate increases. This is due to molecular alignments in the direction of flow and disentanglements. As provided herein, MFR (12, 230°C, 2.16 kg) is determined according to ASTM D-1238-E(20) and is measured in decigrams per minute (dg/min). [0025] The term “activity,” and grammatical variants thereof, refers to the ability of a catalyst system to increase the rate of a reaction, such as polymerization, and is measured in grams per gram per hour (g/g/hr). [0026] The term “percent xylene solubles” or “%XS,” and grammatical variants thereof, refers to the percentage of soluble species in a polymer. The %XS is measured according to ASDM D5492-17 (2017) and is measured by weight or by CRYSTEX® (approved for xylene solubles determination by ISO 16152) (Polymer Char, Valencia, Spain). The %XS is a measure of the crystallinity of a polymer associated with the alignment of its molecular chains, and higher crystallinity may lead to a decrease in MFRs.

[0027] The “intrinsic viscosity ” or “IV” is a measure of a solutes’ contribution to the viscosity of a polymer. The polymers described herein were tested for IV by the use of a soluble fractional analysis instrument (“SFRA”), using a CRYSTEX™ QC, Polymer Char (Valencia, Spain) instrument. The IV is reported in deciliters per gram (dL/g).

ZIEGLER-NATTA CATALYST SYSTEM

[0028] The Ziegler-Natta catalyst system is designed to increase MFR in response to hydrogen of a polyolefin polymer, such as a polypropylene polymer or co-monomer thereof. In particular, the catalyst system comprises a Ziegler-Natta catalyst and at least two external donors of a dialkyl diamino silane (e.g, R¹2Si(NHR²)2) and TEOS. It is shown that the inclusion of the dialkyl diamino silane and TEOS as part of the catalyst system improves both MFR in response to hydrogen, particularly at equal or higher concentrations of the combined external donors to the Ziegler-Natta catalyst, without substantially influencing %XS.

[0029] Suitable Ziegler-Natta catalyst components for use as part of the catalyst system of the present disclosure are not considered to be particularly limited. That is, Ziegler-Natta catalyst components in combination with a dialkyl diamino silane and TEOS, as described herein, can increase MFR response to hydrogen of a polyolefin polymer, without substantially influencing %XS, compared to a Ziegler-Natta catalyst system utilizing traditional external donors. Moreover, the MFR response to hydrogen of the present disclosure is improved relative to a dialkyl diamino silane external donor alone or TEOS alone.

[0030] The Ziegler-Natta catalyst components of the present disclosure include a transition metal, or a transition metal halide, compound, in combination with an alkyl aluminum compound. The transition metal or transition metal halide may be selected from Group IV -VII (e.g., typically titanium, chromium, vanadium, zirconium, and/or hafnium). The alkyl aluminum compound may be an organoaluminumaluminum compound including, but not limited to, a dialkylaluminum (e.g., diethylaluminum chloride); a trialkylaluminum (e.g., triethylaluminum, triisopropylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and triisobutylaluminum), an alkylaluminum halide (e.g, diethylaluminum chloride, diethylaluminum bromide, and diethylaluminum hydride). Any combination of the foregoing may be used. Triethylaluminum may be preferred in the compositions and methods of the present disclosure.

[0031] For example, suitable Ziegler-Natta catalysts may include, but are not limited to, a mixture of TiCl_x, MgCh, or SiCL with Al(Alkyl)3; a mixture of Ti-, Zr-, or Hf-based complexes with methylaluminoxane (MAO); a mixture of titanium tetrachloride (TiCh) with triethylaluminum (Al(C2Hs)3); a mixture of titanium(III) chloride (TiCh) with AlfCdHs)? a mixture of vanadium tetrachloride (VCU) with di ethylaluminum chloride (Al^Hs Cl); a mixture of a magnesium compound (e.g, MgCb) and a titanium compound (e.g. an alkoxy titanium, a titanium halide, an alkoxytitanium halide, any combination thereof) with Al(Alkyl)3 or an Al(Alkyl)2 (e.g., Al(Alkyl)2(Alkenyl)). An example of a suitable Ziegler- Natta catalyst includes the catalyst provided in U.S. Patent Publication No. WO2022/015627, filed on July 12, 2021 and entitled "‘Polymers with Low Levels of Volatile Organic Compounds and Methods of Making Such Polymers,’’ incorporated herein by reference in its entirety. Any combination of the foregoing may be used.

[0032] The dialkyl diamino silane external donors of the present disclosure of the present disclosure are not considered to be particularly limited, provided they are compatible with the selected Ziegler-Natta catalyst and TEOS. The dialkyl diamino silanes for use as an external donor (in combination with TEOS) for polymerization of a polyolefin monomer as described herein may have the formula:

R¹ ₂Si(NHR²)₂, where R¹ is a linear, branched, or cyclic alkyl group having between 3 and 6 carbon atoms, encompassing any value and subset therebetween; and R² is a linear, branched, or cyclic alkyl group having between 1 and 6 carbon atoms, encompassing any value and subset therebetween. For example, in one or more aspects, the dialkyl diamino silane may have the composition of: R¹2Si(NHR²)2. In one or more aspects, R¹ is a cyclic alkyl having 4 carbon atoms, 5 carbon atoms, or 6 carbon atoms, or between 4 and 6 carbon atoms. In one or more aspects, R² is a linear alkyl having 1 to 6 carbon atoms. In one or more aspects, R¹ is a cyclic alkyl having 4 carbon atoms, 5 carbon atoms, or 6 carbon atoms; and R² is a linear alkyd having 1 to 6 carbon atoms.

[0033] In one or more aspects, the catalyst system of the present disclosure may further comprise an internal (electron) donor to modify the surface of a Ziegler-Natta catalyst.

Suitable examples of internal donors may include, but are not limited to an alkyl benzoate, a phthalate, a succinate, a diether, and any combination thereof. [0034] Polymerization of olefins using the Ziegler-Natta catalyst is influenced by the inclusion of the combination of external donors of a dialkyl diamino silane and TEOS, as described herein.

POLYMERIZATION PROCESS WITH ZIEGLER-NATTA CATALYST SYSTEM AND COMBINED DIALKYL DIAMINO SILANE AND TEOS EXTERNAL DONORS

[0035] The Ziegler-Natta catalyst system comprises at least an external donor of a dialkyl diamino silane and TEOS. In one or more preferred aspects, and as described in the Example below, the dialkyl diamino silane external donor comprises the above-described composition of R^SifNHR²^. During olefin polymerization, the Ziegler-Natta catalyst component is coupled with the external donor combination of a dialkyl diamino silane and TEOS in an amount in which TEOS is present in an amount of about 45 wt.% to about 95 wt.% of the dialkyl diamino silane, or about 50 wt.% t or about 90 wt.%, or about 50 wt.% to about 80 wt.%, or about 45 wt.% to about 70 wt%, or about 60 wt.% to about 70 wt.%, or about 70 wt.% to about 80 wt.%, or about 80 wt.% to about 95 wt.%, encompassing any value and subset therebetween. It is noted that TEOS is well known as a poor external donor alone, but when in combination with the dialkyl diamino silane external donors of the present disclosure, even at high concentrations of TEOS, the external donor activity is greatly improved.

[0036] The resultant olefin polymers polymerized in the presence of the catalyst system described herein comprise a xylene soluble component composing less than about 5 wt.%. such as in the range of about 0. 1 wt.% to about 5 wt.%, or about 0.5 wt.% to about 3 wt.%, or about 1 wt.% to about 3 wt.%, or about 2 wt.% to about 3 wt.%, or about 0.5 wt.% to about 1 wt.%, or about 1 wt.% to about 2 wt.%, encompassing any value and subset therebetween.

[0037] The resultant olefin polymers polymerized in the presence of the catalyst system described herein demonstrate an increased MFR response to hydrogen. The MFR will depend on solubility limitations, which include the type of equipment used (e.g., plant equipment that is liquid-full v. lab equipment having a head space) and the hydrogen concentration in propylene. The aforementioned MRF values are based on the definition provided above.

[0038] In any aspect of the present disclosure, the resultant olefin polymers polymerized in the presence of the catalyst system described herein exhibit good activity as would be recognized by one of skill in the art, such as greater than 25,000 g/g/hr, such as in the range of about 25,000 g/g/hr to about 140,000 g/g/hr. or about 30,000 g/g/hr to about 60,000 g/g/hr, or about 40,000 g/g/hr to about 60,000 g/g/hr. encompassing any value and subset therebetween. [0039] Polymerization is performed using certain reaction conditions, such as temperature, pressure, and reaction time suitable for the polymerization of the propylene monomers and any other selected olefin monomers for production of a polypropylene polymer or polypropylene co-polymer, respectively. Suitable monomers, in addition to propylene, include, but are not limited to, ethylene, 1-butene, 1-pentene, 4-methyl-l -pentene, vinylcyclohexane, and any combination thereof. Preferred olefm monomers include propylene alone, propylene in combination with ethylene, and propylene in combination with 1-butene.

[0040] Polymerization is carried out in a reaction zone of one or more reactors, such as a gas phase reactor or other reactor suitable for polymerization. While reaction conditions may vary' depending on a number of factors, such as the particular olefin monomer selections, the following conditions are suitable.

[0041] The polymerization temperatures are preferably about 200°C or lower, and more preferably about 100°C or lower, such as in the range of about 50°C to about 200°C, or about 70°C to about 100°C, encompassing any value and subset therebetween. The polymerization pressure is preferably about 10 MPa or less, and more preferably about 5 MPa or less, such as in the range of about 1 MPa to about 10 MPa, or about 1 MPa to about 5 MPa, encompassing any value and subset therebetween. In addition, the polymerization time, or the residence time during polymerization is normally about 1 minute to about 5 hours, encompassing any value and subset therebetween.

[0042] Examples of the polymerization method include a slurry polymerization method in which a solvent of an inert hydrocarbon compound such as cyclohexane and heptane is used, a bulk polymerization method in which a solvent such as liquefied propylene is used, and a gas phase polymerization method in which a solvent is substantially not used.

EXAMPLE EMBODIMENTS [0043] Nonlimiting example embodiments of the present disclosure include:

[0044] Embodiment A: A catalyst system for the polymerization of olefm monomers comprising: a Ziegler-Natta catalyst; a dialkyl diamino silane external donor; and a tetraethyl orthosilicate (TEOS) external donor.

[0045] Embodiment B: A method comprising: introducing a catalyst system into a reactor, the catalyst system comprising: a Ziegler-Natta catalyst; a dialkyl diamino silane external donor, and a tetraethyl orthosilicate (TEOS) external donor; and feeding olefm monomers into the reaction zone under conditions for polymerization, thereby resulting a polyolefin polymers.

[0046] Nonlimiting example embodiments A and B may include one or more of the following elements:

[0047] Element 1 : Wherein the dialkyl diamino silane is represented by the formula R¹2Si(NHR²)2, where R¹ is a linear, branched, or cyclic alkyl group having between 3 and 6 carbon atoms and R² is a linear, branched, or cyclic alkyl group having between 1 and 6 carbon atoms.

[0048] Element 2: Wherein the dialkyl diamino silane is represented by the formula R¹2Si(NEIR²)2, where R¹ is a cyclic alkyl group having 4 carbon atoms and R² is a linear, branched, or cyclic alkyl group having between 1 and 6 carbon atoms.

[0049] Element 3: Wherein the dialkyl diamino silane is represented by the formula R¹2Si(NEIR²)2, where R¹ is a cyclic alk l group having 5 carbon atoms and R² is a linear, branched, or cy clic alky l group having between 1 and 6 carbon atoms.

[0050] Element 4: Wherein the dialkyl diamino silane is represented by the formula R¹2Si(NHR²)2. where R¹ is a cyclic alkyl group having 6 carbon atoms and R² is a linear, branched, or cyclic alkyl group having between 1 and 6 carbon atoms.

[0051] Element 5: Wherein the dialkyl diamino silane is represented by the formula R’2Si(NHR²)2, where R¹ is a linear, branched, or cyclic alkyl group having between 3 and 6 carbon atoms and R² is a linear alkyl group having between 1 and 6 carbon atoms. [0052] Element 6: Wherein the catalyst system comprises a transition metal compound and an alkyl aluminum compound.

[0053] Element 7: Wherein the catalyst system comprises a transition metal compound and an alkyl aluminum compound, and wherein the transition metal is a transition metal halide.

[0054] Element 8: Wherein the catalyst system comprises a transition metal compound and an alkyl aluminum compound, and wherein the alkylaluminum compound is a dialkylaluminum or a tri alk laluminum.

[0055] Nonlimiting combinations applicable to embodiments A and B include: 1, 2, and/or 5-8; 1 3, and/or 5-8; 1 and/or 5-8; 2 and/or 5-8; 3 and/or 5-8; 4 and/or 5-8; and any combination of 5-8, without limitation. [0056] Nonlimiting example embodiment B may include one or more of the following elements: [0057] Element 9: Wherein the olefin monomers are selected from the group consisting of propylene, ethylene, 1-butene, 1-pentene, 4-methyl-l -pentene, vinylcyclohexane. and any combination thereof.

[0058] Element 10: Wherein the olefin monomers are propylene.

[0059] Element 11 : Wherein the olefin monomers are propylene and ethylene.

[0060] Element 12: Wherein the polyolefin polymers have a xylene solubles value of less than about 3%.

[0061] Element 13: Wherein the polyolefin polymers have a xylene solubles value in the range of about 0.5% to about 3%.

[0062] Nonlimiting combinations applicable to embodiment B include: 9 and 12; 9 and 13; 10 and 12; 10 and 13; 11 and 12; 11 and 13, without limitation.

[0063] To facilitate a better understanding of the embodiments of the present invention, the following example of preferred or representative embodiments are given. In no w ay should the following example be read to limit, or to define, the scope of the invention.

EXAMPLE

[0064] In the following nonlimiting Example, representative compositions and methodologies of the present disclosure for increasing melt flow of polypropylene are provided.

POLYMERIZATION IN THE PRESENCE OF A CATALYST SYSTEM COMPRISING A ZIEGLER-NATTA CATALYST AND EXTERNAL DONORS OF THE COMBINATION OF A DIALKYL DIAMINO SILANE AND TEOS

[0065] Polymerization of polypropylene as carried out using an autoclave having an internal volume of 2.0 liters (L) and equipped with a stirrer in which the internal atmosphere had been completely replaced by nitrogen gas. The autoclave was charged with a representative catalyst system according to the present disclosure comprising 2.0 millimoles (mmol) of triethylaluminum, 0.2 mmol combined external donors of a dialkyl diamino silane DAS1”)) and TEOS (see Table 1 for composition), and a 7.5 mg of a solid Ziegler-Natta catalyst component (7.5 mg).

[0066] The autoclave was charged with 326 mmol of hydrogen gas and 1.25 L of liquefied propylene. After effecting preliminary polymerization at 20°C for 5 minutes under a pressure of 1. 1 Megapascal (MPa), the polymerization reaction was effected at 70°C for 1 hour under a pressure of 3.5 MPa to obtain a propylene polymer (polypropylene). [0067] The results of component analysis for polymerization of propylene are shown in Table 1, where T-l through T-4 are the experimental polymerization runs with TEOS and P-1 through P-3 are the comparative polymerization results with PTES (propyl triethoxysilane).

TABLE 1

[0068] As shown, the combination of dialkyl diamino silane and TEOS show an increase in MFR response to hydrogen. Moreover, the greater the TEOS concentration in the catalyst system (despite being known as a poor external donor), the greater the MFR and. thus, the hydrogen response. Moreover, the addition of DAS1 and TEOS does not substantially influence the %XS at concentrations of less than about 95% TEOS, indicating that cry stallinity has not substantially changed. Comparative PTES samples show' generally higher %XS and substantially no change in MFR. Accordingly, the addition of a combination of external donors of a dialkyl diamino silane and TEOS to a Ziegler-Natta catalyst component can substantially increase hydrogen response and MFR. The results are visually provided in FIGS. 1-3.

[0069] All documents described herein are incorporated by reference herein for purposes of all jurisdictions where such practice is allowed, including any priority documents and/or testing procedures to the extent they are not inconsistent with this text. As is apparent from the foregoing general description and the specific embodiments, while forms of the disclosure have been illustrated and described, various modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, it is not intended that the disclosure be limited thereby. For example, the compositions described herein may be free of any component, or composition not expressly recited or disclosed herein. Any method may lack any step not recited or disclosed herein. Likewise, the term ’comprising" is considered synonymous with the term “including.” Whenever a method, composition, element or group of elements is preceded with the transitional phrase “comprising,” it is understood that we also contemplate the same composition or group of elements with transitional phrases “consisting essentially of,” “consisting of,” “selected from the group of consisting of,” or “is” preceding the recitation of the composition, element, or elements and vice versa.

[0070] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the present specification and associated claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the embodiments of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0071] Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed, including the lower limit and upper limit. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary⁷ meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces. [0072] One or more illustrative embodiments are presented herein. Not all features of a physical implementation are described or shown in this application for the sake of clarity⁷. It is understood that in the development of a physical embodiment of the present disclosure, numerous implementation-specific decisions must be made to achieve the developer's goals, such as compliance with system-related, business-related, government-related and other constraints, which vary by implementation and from time to time. While a developer's efforts might be time-consuming, such efforts would be, nevertheless, a routine undertaking for one of ordinary skill in the art and having benefit of this disclosure. [0073] Therefore, the present disclosure is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present disclosure may be modified and practiced in different but equivalent manners apparent to one having ordinary skill in the art and having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope and spirit of the present disclosure. The embodiments illustratively disclosed herein suitably may be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein.

Claims

CLAIMS What is claimed is:

1. A catalyst system for the polymerization of olefin monomers comprising: a Ziegler-Natta catalyst; a dialkyl diamino silane external donor; and a tetraethyl orthosilicate (TEOS) external donor.

2. The catalyst system of claim 1 , wherein the dialkyl diamino silane is represented by the formula R^SifNHR²^. where R¹ is a linear, branched, or cyclic alkyl group having between 3 and 6 carbon atoms and R² is a linear, branched, or cyclic alkyl group having between 1 and 6 carbon atoms.

3. The catalyst system of claim 2, wherein:

(a) R¹ is a cyclic alkyl group having between 4 and 6 carbon atoms.

(b) R² is a linear alkyl group having between 1 and 6 carbon atoms, or

(c) both (a) and (b).

4. The catalyst system of claim 1 or 2, further comprising a transition metal compound and an alkyl aluminum compound.

5. The catalyst system of claim 4, wherein the transition metal is a transition metal halide.

6. The catalyst system of claim 4, wherein the alkylaluminum compound is a dialkylaluminum or a trialkydaluminum.

7. A method comprising: introducing the catalyst system of claim 1 into a reactor, and, feeding olefin monomers into the reaction zone under conditions for polymerization, thereby resulting a polyolefin polymers.

8. The catalyst system of claim 7, wherein the dialkyl diamino silane is represented by the formula R¹2Si(NHR²)2. where R¹ is a linear, branched, or cyclic alkyl group having between 3 and 6 carbon atoms and R² is a linear, branched, or cyclic alkyl group having between 1 and 6 carbon atoms.

9. The catalyst system of claim 7 or 8, further comprising a transition metal compound and an alkyl aluminum compound.

10. The catalyst system of claim 9, wherein the transition metal is a transition metal halide.

11. The catalyst system of claim 9, wherein the alkyd aluminum compound is a dialkyl aluminum or a trialkylaluminum.

9. The method of any of claims 8-11, wherein the olefin monomers are selected from the group consisting of propylene, ethylene, 1-butene, 1-pentene, 4-methyl-l -pentene, vinylcyclohexane, and any combination thereof.

10. The method of claim 9, wherein the olefin monomers are propylene.

11. The method of claim 9, wherein the olefin monomers are propylene and ethylene.

12. The method of any of claims 8-11, wherein the polyolefin polymers have a xylene solubles value of less than about 5%.

13. The method of any of claims 8-11, wherein the polyolefin polymers have a xylene solubles value in the range of about 0.5% to about 5%.