Carbonate / ester compounds as activity limiting agents in Ziegler-Natta catalyst compositions for olefin polymerization

Abstract

The present invention discloses a Ziegler-Natta catalyst composition comprising: one or more Ziegler-Natta procatalyst compositions comprising magnesium, titanium, a halogen, one or more internal electron donors; one or more aluminum-containing co-catalysts; optionally one or more stereoselectivity control agents (SCAs); and one or more activity limiting agents (ALA) including one or more alkyl-, cycloalkyl-or aryl carbonates and derivatives. Such Ziegler-Natta catalyst compositions exhibit self-limiting catalyst activity in the polymerization of olefins, particularly propylene.

Description

background 1. Technical Field

[0001] The present invention relates to a Ziegler-Natta catalyst composition, comprising: one or more Ziegler-Natta precatalyst compositions, which include magnesium, titanium, halogen, one or more internal electron donors; one or more aluminum-containing cocatalysts; optionally one or more external stereoselectivity control agents (SCA); and one or more activity limiting agents (ALA), which include one or more alkyl-, cycloalkyl- or aryl carbonates and derivatives. The present invention also relates to a method for preparing the novel polymerization catalyst composition, and a polymerization process for producing polyolefins (especially polypropylene) using the novel catalyst composition. 2. Description of Related Technology

[0002] Ziegler-Natta catalyst compositions for olefin polymerization are well known in the art. Typically, these catalyst systems consist of a solid Ziegler-Natta procatalyst component and a cocatalyst component (typically an organoaluminum compound). In order to increase the activity and stereoselectivity of the catalyst system for alpha-olefin polymerization, an electron donating compound has been incorporated into the Ziegler-Natta procatalyst component during the catalyst preparation process to serve as an internal electron donor, and / or the electron donating compound can be loaded into the polymerization reactor during the polymerization process and used as an external stereoselectivity control agent (SCA) together with the solid Ziegler-Natta procatalyst component and the cocatalyst component.

[0003] Common internal electron donor compounds incorporated in the process of preparing solid Ziegler-Natta procatalyst components are well known in the art, and common internal electron donor compounds include organic acid esters, ethers, ketones, amines, alcohols, heterocyclic organic compounds, phenols, phosphines and silanes, etc. It is generally known in the art that the polymerization activity and the stereoregularity, molecular weight and molecular weight distribution of the produced polymer depend on the molecular structure of the internal electron donor used. Therefore, in order to improve the polymerization process and the properties of the produced polymer, people have been working hard and pursuing the development of various internal electron donors. Examples of such internal electron donor compounds and their use as components of catalyst systems are described in U.S. Patent Nos. 4,107,414; 4,186,107; 4,226,963; 4,347,160; 4,382,019; 4,435,550; 4,465,782; 4,522,930; 4,530,912; 4,532,313; 4,560,671; 4,65 7,882; 5,208,302; 5,902,765; 5,948,872; 6,048,818; 6,121,483; 6,281,301; 6,294,497; 6,313,238; 6,395,670, 6,436,864, 6,605,562; 6,716,939; 6,770,586; 6,818,583; 6,825,309 ; 7,022,640; 7,049,377; 7,202,314; 7,208,435; 7,223,712; 7,351,778; 7,371,802; 7,491,781; 7,544,748; 7,674,741; 7,674,943; 7,888,437; 7,888,438; 7,935,766; 7,964,678; 8,00 3,558; 8,003,559; 8,088,872; 8,211,819; 8,222,357; 8,227,370; 8,236,908; 8,247,341; 8,263,520; 8,263,692; 8,288,304; 8,288,585; 8,288,606; 8,318,626; 8,383,540; 8,536,290 8,569,195; 8,575,283; 8,604,146; 8,633,126; 8,692,927; 8,664,142; 8,680,222; 8,716,514 and 8,742,040, the entire contents of which are incorporated herein by reference.

[0004] Acceptable external stereoselectivity control agents (SCAs) include organic compounds containing O, Si, N, S and / or P. Such compounds include organic acids, organic acid esters, organic acid anhydrides, ethers, ketones, alcohols, aldehydes, silanes, amides, amines, amine oxides, thiols, and various phosphates and amides, etc. Preferred SCA components are organosilicon compounds containing Si-OC and / or Si-NC bonds with a central atom being silicon. Such compounds are described in U.S. Patent Nos. 4,472,524; 4,473,660; 4,560,671; 4,581,342; 4,657,882; 5,106,807; 5,407,883; 5,684,173; 6,228,961; 6,362,124; 6,552,136; 6,689,849; 7,009,015; 7,244,794; 7,276,463; 7,619,049; 7,790,819; 8,247,504; 8,648,001 and 8,614,162, the entire contents of which are incorporated herein by reference.

[0005] With respect to the dependence of catalyst activity on temperature, activity limiting agents (ALAs) have recently been developed. The use of certain carboxylic acid esters, diethers, and derivatives in conjunction with a Ziegler-Natta procatalyst composition and an external SCA results in a catalyst composition that is inherently self-limiting with respect to temperature. Such catalyst compositions have less activity at elevated temperatures, particularly temperatures above 100°C, than the catalyst activity under typical polymerization conditions where the reaction temperature is typically below 80°C. Advantages of using such catalyst compositions include less fouling or sheeting of the reactor and improved control of the polymerization process. Examples of such ester and diether compounds and their use as ALAs are described in these U.S. Patent Nos.: 7,491,670; 7,678,868; 7,781,363; 8,536,290; 9,796,796 and 10,926,234, the entire contents of which are incorporated herein by reference.

[0006] Despite the advances made by the foregoing disclosures, there remains a need and desire to develop catalyst compositions which not only have reduced polymerization activity at elevated temperatures, but also produce polyolefins having well-controlled physical properties, particularly when the reaction temperature is above the normal range. Summary of the invention

[0007] The present invention is a Ziegler-Natta catalyst composition, comprising: one or more Ziegler-Natta precatalyst compositions, which include magnesium, titanium, halogen, one or more internal electron donors; one or more aluminum-containing cocatalysts; optionally one or more stereoselectivity control agents (SCA); and one or more activity limiting agents (ALA), which include one or more alkyl-, cycloalkyl- or aryl carbonates and derivatives. In one embodiment of the present invention, the Ziegler-Natta catalyst composition exhibits self-limiting catalyst activity in olefin polymerization (especially propylene polymerization) to meet the aforementioned needs.

[0008] The present invention relates to a catalyst system for the polymerization or copolymerization of alpha-olefins, comprising: a solid Ziegler-Natta procatalyst component, a cocatalyst component, optionally an external SCA component, and a carbonate / ester compound as an ALA component. Suitable ALA carbonate / ester compounds in the catalyst composition of the present invention are represented by formula I: R 1 OC(=O)OR 2 [Formula I] Where R 1 and R 2 may be the same or different and independently selected from: hydrogen, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 4 to 20 carbon atoms, or a heteroatom of a hydrocarbon group containing 1 to 20 carbon atoms, wherein R 1 and R 2 They may be linked to form one or more saturated or unsaturated monocyclic or polycyclic rings. Description of the Preferred Embodiments

[0009] The present invention provides a catalyst composition for the polymerization and copolymerization of olefins, in particular propylene or a mixture of propylene and comonomers, the catalyst composition comprising: one or more Ziegler-Natta procatalyst compositions comprising magnesium, titanium, halogen, one or more internal electron donors; one or more aluminum-containing cocatalysts; optionally one or more external stereoselectivity control agents (SCA); and one or more activity limiting agents (ALA), comprising one or more alkyl-, cycloalkyl- or aryl carbonates and derivatives, the ALA compound being charged to the polymerization reactor in an amount such that the polymerization activity of the catalyst composition at a temperature above 85°C, preferably above 100°C, is less than the polymerization activity of the catalyst composition without ALA at said temperature.

[0010] According to certain aspects of the present invention, suitable carbonate compounds in the catalyst composition of the present invention are represented by Formula I: R 1 OC(=O)OR 2 [Formula I] Where R1 and R 2 may be the same or different and independently selected from: hydrogen, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 4 to 20 carbon atoms, or a heteroatom of a hydrocarbon group containing 1 to 20 carbon atoms, wherein R1 and R 2 They may be linked to form one or more saturated or unsaturated monocyclic or polycyclic rings.

[0011] Preferred examples of suitable carbonate / ester compounds of Formula I include, but are not limited to: dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, di-n-butyl carbonate, propylene carbonate, 2-ethoxyethyl ethyl carbonate, dilauryl carbonate, diphenyl carbonate, tert-butylphenyl carbonate, bis(4-chlorophenyl) carbonate, 3,4-dichlorobenzylhexyl carbonate, ethylene glycol bis-(methyl carbonate), diethyl 2,5-dioxaadipate.

[0012] Conventional and acceptable Ziegler-Natta catalyst compositions that can be used according to the present invention include: (a) a solid Ziegler-Natta procatalyst component, (b) a cocatalyst component, optionally (c) one or more stereoselectivity control agents (SCA), and (d) one or more carbonate / ester compounds of Formula I used as activity limiting agents (ALA).

[0013] Preferred solid Ziegler-Natta procatalyst components (a) comprise a solid catalyst component comprising a titanium compound having at least a Ti-halogen bond and an internal electron donor and supported on an anhydrous magnesium dihalide support. Such preferred solid Ziegler-Natta procatalyst components (a) comprise a solid catalyst component comprising a titanium tetrahalide. Preferred titanium tetrahalides are TiCl 4 Alkoxy halides can also be used as solid Ziegler-Natta procatalyst component (a).

[0014] The internal electron donor used to prepare the solid Ziegler-Natta procatalyst component (a) can be selected from commonly used internal donors such as aliphatic / aromatic esters, phthalates, aliphatic / aromatic 1,3-diethers, malonates, succinates, carbonate / ester compounds. In some embodiments, the internal donor can be selected from diisobutyl phthalate, di-n-butyl phthalate, diisooctyl phthalate, 1,3-dipentyl phthalate, ethyl benzoate, ethyl benzoate, n-butyl benzoate, methyl p-toluate and methyl p-methoxybenzoate and diisobutyl phthalate, diethyl diisobutyl malonate, diethyl isopropyl malonate, diethyl phenyl malonate, dimethyl diisobutyl malonate, dimethyl phenyl malonate, 9,9-bis( 9,9-bis(methoxymethyl)-2,3,6,7-tetramethylfluorene; 9,9-bis(methoxymethyl)-2,3,4,5,6,7-hexafluorofluorene; 9,9-bis(methoxymethyl)-2,3-benzofluorene; 9,9-bis(methoxymethyl)-2,3,6,7-dibenzofluorene; 9,9-bis(methoxymethyl)-2,7-diisopropylfluorene; 9,9-bis(methoxymethyl)-1,8-dichlorofluorene; 9,9-bis(methoxymethyl)-2 ,7-dicyclopentylfluorene; 9,9-bis(methoxymethyl)-1,8-difluorofluorene; 9,9-bis(methoxymethyl)-1,2,3,4-tetrahydrofluorene; 9,9-bis(methoxymethyl)-1,2,3,4,5,6,7,8-octahydrofluorene; 9,9-bis(methoxymethyl)-4-tert-butylfluorene, 2,3-bis(trimethylsilyl)succinic acid diethyl ester, 2,3-bis(2-ethylbutyl)succinic acid diethyl ester, 2,3-dibenzylsuccinic acid diethyl ester, 2,3-di Diethyl isopropylsuccinate, dibutyl 2,3-diisopropylsuccinate, diethyl 2,3-bis(cyclohexylmethyl)succinate, diethyl 2,3-diisobutylsuccinate, diethyl 2,3-dineopentylsuccinate, diethyl 2,3-dicyclopentylsuccinate, diethyl 2,3-dicyclohexylsuccinate, other common internal electron donors including alkyl or alkyl-aryl ethers, polyethers, ketones, monoamines or polyamines, heterocyclic organic compounds, aldehydes and P-containing compounds (e.g., phosphines and phosphoramides) can also be used.

[0015] Acceptable anhydrous magnesium dihalides forming the support of the solid Ziegler-Natta procatalyst component (a) are magnesium dihalides in active form well known in the art. Such magnesium dihalides may be preactivated, activated in situ during the titanation process, generated in situ from a magnesium compound capable of generating magnesium dihalide when treated with a suitable halogen-containing transition metal compound and subsequently activated. Preferred magnesium dihalides are magnesium dichloride and magnesium dibromide. The water content of the dihalide is generally less than 1% by weight.

[0016] The solid Ziegler-Natta procatalyst component (a) can be prepared by a variety of methods. One method consists in the following manner: co-grinding the magnesium dihalide and the internal electron donor compound until the surface area of ​​the product is greater than 20 m 2 / g, and thereafter reacting the ground product with a Ti compound. Other methods for preparing solid Ziegler-Natta procatalyst component (a) are disclosed in U.S. Pat. Nos. 4,220,554, 4,294,721, 4,315,835, 4,330,649, 4,439,540, 4,816,433, and 4,978,648. These methods are incorporated herein by reference.

[0017] In a typical solid Ziegler-Natta procatalyst component (a), the molar ratio between the magnesium dihalide and the halogenated titanium compound is between 1 and 500, and the molar ratio between the halogenated titanium compound and the internal electron donor is between 0.1 and 50.

[0018] Preferred co-catalyst components (b) comprise alkylaluminum compounds. Acceptable alkylaluminum compounds include trialkylaluminums, such as triethylaluminum, triisobutylaluminum and triisopropylaluminum. Other acceptable alkylaluminum compounds include dialkylaluminum hydrides (such as diethylaluminum hydride). Other acceptable co-catalyst components (b) include compounds containing two or more aluminum atoms connected to each other by hetero-atoms, such as: (C 2 H 5 ) 2 Al-O-Al(C 2 H 5 ) 2 (C 2 H 5 ) 2 Al-N(C 6 H 5 )-Al(C 2 H 5 ) 2 ;and (C 2 H 5 ) 2 Al-O-SO 2 -O-Al(C 2 H 5 ) 2 .

[0019] Acceptable external stereoselectivity control agents (SCAs) (c) are organic compounds containing O, Si, N, S and / or P. Such compounds include organic acids, organic acid esters, organic acid anhydrides, ethers, ketones, alcohols, aldehydes, silanes, amides, amines, amine oxides, thiols, various phosphates and amides, etc. Preferred SCA components (c) are organosilicon compounds containing Si-OC and / or Si-NC bonds. Specific examples of such organosilicon compounds are trimethylmethoxysilane, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, diisopropyldimethoxysilane, dicyclopentyldimethoxysilane, isobutyltriethoxysilane, vinyltrimethoxysilane, dicyclohexyldimethoxysilane, 3-tert-butyl-2-isobutyl-2-methoxy-[1,3,2]oxazidosilane, 3-tert-butyl-2-cyclopentyl-2-methoxy- [1,3,2]oxazasilane, 2-bicyclo[2.2.1]hept-5-en-2-yl-3-tert-butyl-2-methoxy-[1,3,2]oxazasilane, 3-di-tert-butyl-2,2-diethoxy-[1,3,2]oxazasilane, 4,9-di-tert-butyl-1,6-dioxa-4,9-diaza-5-silane-spiro[4.4]nonane, bis(perhydroisoquinolinyl)dimethoxysilane, etc. A mixture of organic electron donors can also be used.

[0020] The olefin polymerization process that may be used according to the present invention is essentially unlimited. For example, when used, the catalyst components (a), (b), (c) and (d) may be added to the polymerization reactor simultaneously or sequentially. Preferably, components (b), (c) and (d) are first mixed and then the resulting mixture is contacted with component (a) before the polymerization reaction.

[0021] The olefin monomer may be added before, simultaneously with, or after the Ziegler-Natta catalyst composition is added to the polymerization reactor. Preferably, the olefin monomer is added after the Ziegler-Natta catalyst composition is added.

[0022] The molecular weight of the polymer can be controlled in a known manner, preferably by using hydrogen. With the catalyst produced according to the present invention, when the polymerization reaction is carried out at a relatively low temperature (e.g., from about 30° C. to about 95° C.), the molecular weight can be suitably controlled with hydrogen. This control of the molecular weight can be demonstrated by a measurable positive change in the melt flow rate (MFR).

[0023] The polymerization reaction can be carried out in a slurry, liquid or gas phase process, or in a combination of a liquid and gas phase process using a separate reactor, all of which can be carried out batchwise or continuously. According to conventional known methods, polyolefins can be obtained directly from a gas phase process, or by isolating and recovering the solvent from a slurry process.

[0024] The polymerization conditions for producing polyolefin by the method of the present invention are not particularly limited, such as polymerization temperature, polymerization time, polymerization pressure, monomer concentration, etc. The polymerization temperature is generally from 40 to 90° C., and the polymerization pressure is generally 1 atmosphere or higher.

[0025] The Ziegler-Natta catalyst composition of the present invention can be pre-contacted (known in the art as prepolymerization) with a small amount of olefin monomer in a hydrocarbon solvent at 60°C or less for a time sufficient to produce an amount of polymer from 0.5 to 5 times the weight of the catalyst. If such prepolymerization is carried out in liquid or gaseous monomer, the amount of polymer produced is generally up to 1000 times the weight of the catalyst.

[0026] The Ziegler-Natta catalyst composition of the present invention facilitates the polymerization of olefins, including but not limited to homopolymerization and copolymerization of alpha olefins. Suitable alpha olefins that can be used in the polymerization process according to the present invention include those of the general formula CH 2 =CHR olefins, where R is H or C 1-10 Straight or branched chain alkyl, such as ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene and 1-octene. Although the Ziegler-Natta catalyst composition of the present invention can be used in the process of ethylene polymerization, it is more desirable to use the Ziegler-Natta catalyst composition of the present invention in the process of polypropylene or higher olefin polymerization. Preferably, the process involves homopolymerization or copolymerization of propylene. Example

[0027] In order to better understand the above, the following non-limiting examples are provided. Although the examples may be directed to specific embodiments, they should not be considered to limit the present invention in any particular aspect. The activity value (AC) is based on the grams of polymer produced per gram of solid catalyst component used.

[0028] The following analytical methods were used to characterize the polymers.

[0029] Heptane insoluble matter (HI %): the weight percentage (wt %) remaining in a polypropylene sample after extraction with boiling heptane for 8 hours.

[0030] Melt flow rate (MFR): ASTM D-1238, measured at 230°C under a load of 2.16 kg.

[0031] Magnesium ethoxide (98%), anhydrous toluene (99.8%), TiCl 4(99.9%), anhydrous n-heptane (99%), diisobutyl phthalate (99%), cyclohexyl(dimethoxy)methylsilane (C-donor, ≥99%), and triethylaluminum (93%) were purchased from Sigma-Aldrich Co., Milwaukee, WI, USA. Diisopropyldimethoxysilane (P-donor) was purchased from Gelest, Inc., Morrisonville, PA, USA. 2-Ethoxyethyl ethyl carbonate and 2-isopropyl-2-(1-methylbutyl)-1,3-dimethoxypropane were provided by Toho Titanium Co., LTD. Diethyl carbonate (98%) and di-n-butyl carbonate (98%) were purchased from TCI America.

[0032] Unless otherwise stated, all reactions were performed under an inert atmosphere. Example 1 (A) Preparation of solid catalyst component (A-1)

[0033] A three-necked 250 ml flask equipped with a sintered filter disk and a mechanical stirrer was thoroughly purged with nitrogen and charged with 80 mmol of magnesium ethoxide and 80 ml of anhydrous toluene to form a suspension. 20 ml of TiCl 4 , and then the reaction mixture was heated to 90°C. 10 mmol of diisobutyl phthalate (DIBP) was added thereto as an internal electron donor, and then heated to 110°C and stirred at this temperature for 2 hours. After the reaction was completed, the solid produced was filtered and washed (100 ml of anhydrous toluene) at 90°C for two rounds, and 80 ml of fresh anhydrous toluene and 20 ml of TiCl were added thereto. 4 The reaction was stirred for additional two hours at 110° C. After the reaction was completed, the solid was subjected to 7 rounds of filtration and washing (100 ml of anhydrous n-heptane) at 90° C., and dried under reduced pressure to obtain a solid composition (A-1). (B) Propylene Slurry Polymerization

[0034] Propylene polymerization was carried out in a laboratory scale 2-liter reactor according to the following procedure.

[0035] The reactor was preheated to at least 100°C and purged with nitrogen to remove residual moisture and oxygen. The reactor was then cooled to 50°C. Under nitrogen, 1 liter of dry heptane was introduced into the reactor. When the reactor temperature was about 50°C, 4.3 ml of triethylaluminum (0.6 M in hexane), 0.4 ml of diisopropyl(dimethoxy)silane (P-donor) (0.5 M in heptane), 1.0 ml of diethyl carbonate solution (0.3 M in heptane) and 30 mg of the above-prepared solid catalyst component (A-1) were added to the reactor. The temperature of the reactor was heated to 50°C, and 30 psi of hydrogen in a 150 ml vessel was flushed into the reactor with propylene.

[0036] The temperature of the reactor was then raised to 70°C or above. The total reactor pressure was raised to and controlled at 90 psig by continuously introducing propylene into the reactor, and the polymerization was allowed to proceed for 1 hour. After the polymerization, the reactor was vented to reduce the pressure to 0 psig, and the temperature of the reactor was cooled to 50°C. The reactor was then opened. 500 ml of methanol was added to the reactor, and the resulting mixture was stirred for 5 minutes and then filtered to obtain a polymer product. The polymer obtained was vacuum dried at 80°C for 6 hours.

[0037] The polymers were evaluated for melt flow rate (MFR), heptane insolubles (HI%). Catalyst activity (AC) was also measured. The results are shown in Table 1. Example 2 (B) Propylene Slurry Polymerization

[0038] The propylene polymerization using the catalyst component (A-1) was carried out in the same manner as described in Example 1, except that 1.0 ml of di-n-butyl carbonate solution (0.3 M in heptane) was used instead of 1.0 ml of diethyl carbonate solution (0.3 M in heptane). Example 3 (B) Propylene Slurry Polymerization

[0039] Propylene polymerization using catalyst component (A-1) was carried out in the same manner as described in Example 1, except that 0.67 ml of 2-ethoxyethyl ethyl carbonate (0.3 M in heptane) was used instead of 1.0 ml of diethyl carbonate solution (0.3 M in heptane). Example 4 (A) Preparation of solid catalyst component (A-2)

[0040] The preparation of solid catalyst component (A-2) was carried out in the same manner as described in Example 1, except that 7.5 mmol 2-isopropyl-2-(1-methylbutyl)-1,3-dimethoxypropane and 7.5 mmol diethyl 2,3-diisopropylsuccinate were added instead of 10 mmol diisobutyl phthalate (DIBP) as internal electron donors to prepare catalyst component (A-2). (B) Propylene Slurry Polymerization

[0041] Propylene polymerization using catalyst component (A-2) was carried out in the same manner as described in Example 1 except that 0.67 ml of diethyl carbonate solution (0.3 M in heptane) was charged and 10 psi of hydrogen in a 150 ml vessel was flushed into the reactor with propylene. Comparative Example 1 (B) Propylene Slurry Polymerization

[0042] The results are shown in Table 1. Propylene polymerization using the catalyst component (A-1) was carried out in the same manner as described in Example 1, except that diethyl carbonate was not added. Comparative Example 2 (B) Propylene Bulk Polymerization

[0043] The results are shown in Table 1. Propylene polymerization using the catalyst component (A-2) was carried out in the same manner as described in Example 4, except that diethyl carbonate was not added. Table 1

[0044] As can be clearly seen from the above results shown in Table 1, the reduction in polymerization activity at elevated polymerization temperatures is achieved by using carbonate compounds as activity limiting agents (ALA) in accordance with the teachings of the present invention. This is compared and contrasted with the use of silane (SCA) compounds alone and with the use of the same SCA / ALA mixture at lower polymerization temperatures. For example, in Table 1, the polymerization activities at 100°C of Examples 1, 2, and 3 are about 40% of the activity at 70°C of Comparative Example 1, while the polymerization activity at 100°C is about 60% of the activity at 70°C without carbonate compounds as ALA. Also, the polymerization activity at 100°C of Example 4 is 27% of the activity at 70°C of Comparative Example 2, while the polymerization activity at 95°C is about 50% of the activity at 70°C without carbonate compounds as ALA. These illustrate the self-limiting polymerization properties of the compositions. Furthermore, one skilled in the art will appreciate from the data that the presence of the carbonate compound as ALA in the catalyst composition improves polymer isotacticity (HI %) compared to the corresponding comparative example.

[0045] In another embodiment of the present invention, a catalyst composition for polymerizing olefins (preferably propylene) is provided, comprising: one or more Ziegler-Natta procatalyst components, magnesium, titanium, halogen, and one or more internal electron donors; one or more aluminum-containing co-catalysts; and one or more activity limiting agents (ALA), including one or more alkyl-, cycloalkyl- or aryl carbonates and their derivatives.

[0046] In a preferred aspect of this embodiment, at least one of the one or more ALAs is represented by Formula I: R 1 OC(=O)OR 2 [Formula I] R 1 and R 2 is independently selected from: hydrogen, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 4 to 20 carbon atoms, or a heteroatom of a hydrocarbon group containing 1 to 20 carbon atoms; and wherein R 1 and R 2 They may be linked to form one or more saturated or unsaturated monocyclic or polycyclic rings.

[0047] In a preferred aspect of this embodiment, in the catalyst composition, the one or more ALAs are diethyl carbonate, di-n-butyl carbonate, or 2-ethoxyethyl ethyl carbonate, although it is contemplated that the one or more ALAs may be selected from: dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, di-n-butyl carbonate, propylene carbonate, 2-ethoxyethyl ethyl carbonate, dilauryl carbonate, diphenyl carbonate, tert-butylphenyl carbonate, bis(4-chlorophenyl) carbonate, 3,4-dichlorobenzylhexyl carbonate, ethylene glycol bis-(methyl carbonate), or diethyl 2,5-dioxaadipate.

[0048] In a preferred aspect of this embodiment, the catalyst composition may further comprise one or more external stereoselectivity control agents (SCAs), preferably compounds comprising Si-OC or Si-NC bonds, wherein silicon is the central atom in the compound.

[0049] According to these teachings, the resulting polymerization activity at 100°C is less than 43% of the polymerization activity at 70°C of the catalyst composition without one or more ALAs, or less than 39% of the polymerization activity at 70°C of the catalyst composition without one or more ALAs, or less than 37% of the polymerization activity at 70°C of the catalyst composition without one or more ALAs, or less than 27% of the polymerization activity at 70°C of the catalyst composition without one or more ALAs.

[0050] In another embodiment of the present invention, a method for polymerizing olefins (preferably propylene) using the catalyst composition described above is disclosed. According to certain teachings of the present disclosure, the resulting polymerization activity at 100°C is less than 43% of the polymerization activity at 70°C of the catalyst composition without one or more ALAs, or less than 39% of the polymerization activity at 70°C of the catalyst composition without one or more ALAs, or less than 37% of the polymerization activity at 70°C of the catalyst composition without one or more ALAs, or less than 27% of the polymerization activity at 70°C of the catalyst composition without one or more ALAs.

[0051] Therefore, the present invention is well adapted to achieve the objects and advantages mentioned as well as those inherent therein. The specific embodiments disclosed above are illustrative only, as it is apparent to those skilled in the art having the benefit of the teachings herein that the present invention may be modified or practiced in different but equivalent manners. In addition, the construction or design details shown herein are not limited unless described in the following claims. Therefore, it is apparent that the specific exemplary embodiments disclosed above may be adjusted or modified, and all such variations are considered to be within the scope and spirit of the present invention. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number falling within the range is specifically disclosed. In addition, the indefinite article "a" or "an" used in the claims is defined herein as the element or elements it introduces.

Claims

1. A catalyst composition for olefin polymerization, comprising: one or more Ziegler-Natta procatalyst components including magnesium, titanium, a halogen, and one or more internal electron donors; one or more aluminum-containing co-catalysts; and One or more activity limiting agents (ALA) including one or more alkyl-, cycloalkyl- or aryl carbonates and derivatives thereof.

2. The catalyst composition of claim 1, wherein at least one of the one or more ALAs is represented by Formula I: R 1 OC(=O)OR 2 [Formula I] Where R1 and R 2 independently selected from: hydrogen, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 4 to 20 carbon atoms, or a heteroatom of a hydrocarbon group containing 1 to 20 carbon atoms; and Where R1 and R 2 They may be linked to form one or more saturated or unsaturated monocyclic or polycyclic rings.

3. The catalyst composition of claim 1, wherein the one or more ALAs are selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, di-n-butyl carbonate, propylene carbonate, 2-ethoxyethyl ethyl carbonate, dilauryl carbonate, diphenyl carbonate, tert-butylphenyl carbonate, bis(4-chlorophenyl) carbonate, 3,4-dichlorobenzylhexyl carbonate, ethylene glycol bis-(methyl carbonate), or diethyl 2,5-dioxaadipate.

4. The catalyst composition of claim 1, wherein the one or more ALAs comprise diethyl carbonate.

5. The catalyst composition of claim 1, wherein the one or more ALAs comprise di-n-butyl carbonate.

6. The catalyst composition of claim 1, wherein the one or more ALAs comprise 2-ethoxyethyl ethyl carbonate.

7. The catalyst composition of claim 1, wherein the olefin comprises propylene.

8. The catalyst composition of claim 1, further comprising one or more external stereoselectivity control agents (SCAs).

9. The catalyst composition of claim 8, wherein at least one of the SCAs is a compound comprising a Si-OC or Si-NC bond, wherein silicon is the central atom in the compound.

10. The catalyst composition of claim 1, which has a polymerization activity at 100°C that is less than 43% of the polymerization activity at 70°C of a catalyst composition that does not contain one or more ALAs.

11. The catalyst composition of claim 1, which has a polymerization activity at 100°C that is less than 39% of the polymerization activity at 70°C of a catalyst composition that does not contain the one or more ALAs.

12. The catalyst composition of claim 1, which has a polymerization activity at 100°C that is less than 37% of the polymerization activity at 70°C of a catalyst composition that does not contain the one or more ALAs.

13. The catalyst composition of claim 1, which has a polymerization activity at 100°C that is less than 27% of the polymerization activity at 70°C of a catalyst composition that does not contain one or more ALAs.

14. A method for polymerizing olefins, comprising: A catalyst composition is provided, comprising: one or more Ziegler-Natta procatalyst components, including magnesium, titanium, halogen, and one or more internal electron donors; one or more aluminum-containing cocatalysts; and one or more activity limiting agents (ALA), including one or more alkyl-, cycloalkyl- or aryl carbonates and derivatives thereof; The olefin is reacted with the catalyst composition to form a polyolefin.

15. The method of claim 14, wherein at least one of the one or more ALAs is represented by Formula I: R 1 OC(=O)OR 2 [Formula I] R1 and R 2 independently selected from hydrogen, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 4 to 20 carbon atoms, or a heteroatom of a hydrocarbon group containing 1 to 20 carbon atoms; and wherein R1 and R 2 They may be linked to form one or more saturated or unsaturated monocyclic or polycyclic rings.

16. The method of claim 14, wherein the one or more ALAs are selected from dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, di-n-butyl carbonate, propylene carbonate, 2-ethoxyethyl ethyl carbonate, dilauryl carbonate, diphenyl carbonate, tert-butylphenyl carbonate, bis(4-chlorophenyl) carbonate, 3,4-dichlorobenzylhexyl carbonate, ethylene glycol bis-(methyl carbonate), or diethyl 2,5-dioxaadipate.

17. The method of claim 14, wherein the one or more ALAs comprise diethyl carbonate.

18. The method of claim 14, wherein the one or more ALAs include di-n-butyl carbonate.

19. The method of claim 14, wherein the one or more ALAs comprise 2-ethoxyethyl ethyl carbonate.

20. The method of claim 14, wherein the olefin comprises propylene.

21. The method of claim 14, further comprising one or more external stereoselectivity control agents (SCAs).

22. The method of claim 21, wherein at least one of the SCAs is a compound comprising Si-OC or Si-NC bonds, wherein silicon is a central atom in the compound.

23. The method of claim 14, which results in a polymerization activity at 100°C that is less than 43% of the polymerization activity at 70°C of a catalyst composition that does not contain one or more ALAs.

24. The method of claim 14, which results in a polymerization activity at 100°C that is less than 39% of the polymerization activity at 70°C of a catalyst composition that does not contain one or more ALAs.

25. The method of claim 14, which results in a polymerization activity at 100°C that is less than 37% of the polymerization activity at 70°C of a catalyst composition that does not contain one or more ALAs.

26. The method of claim 14, which results in a polymerization activity at 100°C that is less than 27% of the polymerization activity at 70°C of a catalyst composition that does not contain one or more ALAs.

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