Controlling long chain branching content with dual activator-supports

Abstract

A method for controlling the long chain branch content of ethylene homopolymers and copolymers produced in a polymerization process includes the steps of contacting a metallocene compound, an organoaluminum compound, a high LCB activator-support, and a low LCB activator-support to form a catalyst composition, contacting the catalyst composition with ethylene and optionally an olefin comonomer in a polymerization reactor system under polymerization conditions to produce an ethylene polymer having an LCB content, and controlling the relative amounts of the high LCB activator-support and the low LCB activator-support in the catalyst composition to adjust the LCB content of the ethylene polymer.

Description

Technical Field

[0001] This disclosure relates to metallocene-based catalyst systems containing activator-supports, and more specifically to a method for controlling the long-chain branching (LCB) content of olefin-based polymers produced using the catalyst system by adjusting the relative amounts of different activator-supports in the catalyst system. Background Technology

[0002] Metallocene-based catalyst systems can be used to polymerize olefins to produce olefin-based polymers, such as ethylene / α-olefin copolymers. To produce polymers with lower or higher LCB contents, a suitable metallocene compound is selected for use in the catalyst system. However, replacing one metallocene compound with another to increase or decrease long-chain branching can significantly affect many other polymer properties, particularly melt index, molecular weight distribution, and short-chain branching. It would be advantageous to produce polymers with higher or lower LCB contents without needing to replace the metallocene component in the catalyst system. Therefore, this disclosure is generally aimed at this objective. Summary of the Invention

[0003] The present invention is provided to introduce, in a simplified form, a series of concepts that will be further described in the detailed description below. The present invention is not intended to identify any essential or necessary features of the claimed subject matter. Nor is the present invention intended to limit the scope of the claimed subject matter.

[0004] In one aspect of the invention, a polymerization process is disclosed, and in this aspect, the process may include (a) contacting a metallocene compound, an organoaluminum compound, a first (high LCB) activator-support, and a second (low LCB) activator-support to form a catalyst composition, (b) in a polymerization reactor system, contacting the catalyst composition with ethylene and optionally an olefin comonomer under polymerization conditions to produce an ethylene polymer having a long chain branching (LCB) content, and (c) controlling the relative amounts of the first (high LCB) activator-support and the second (low LCB) activator-support in the catalyst composition of step (a) to adjust the LCB content of the ethylene polymer.

[0005] In another aspect of the invention, a catalyst composition is disclosed, wherein the catalyst composition may comprise (i) a first activator-support comprising a fluorinated solid oxide, (ii) a second activator-support comprising a sulfated solid oxide, (iii) a metallocene compound, and (iv) an organoaluminum compound. For example, the first activator-support may comprise alumina coated with fluorinated silica, while the second activator-support may comprise sulfated bentonite, sulfated alumina, or a combination thereof.

[0006] Both the foregoing summary and the following detailed description provide examples and are illustrative only. Therefore, the foregoing summary and the following detailed description should not be considered limiting. Furthermore, features or variations may be provided in addition to those set forth herein. For example, certain aspects may be addressed to various combinations and sub-combinations of features described in the detailed description. Attached Figure Description

[0007] The following figures form part of this specification and are included to further illustrate certain aspects of the invention. The invention can be better understood by referring to one or more of these figures, as well as to the specific embodiments and examples.

[0008] Figure 1 The graph shows the phase angle (δ in °) of the polymers in Examples 1-4 compared to the logarithm of the complex modulus (G* in Pa). Figure 2 This is a graph showing the logarithm of the complex modulus to the δ of the polymers in Examples 5-7.

[0009] Figure 3 The Janzen-Colby logarithmic graphs show the zero-shear viscosity (η0 in Pa-sec) of the polymers in Examples 1-4 compared to their weight-average molecular weight (Mw in g / mol). Figure 4 Janzen-Colby logarithmic graphs of zero-shear viscosity versus weight-average molecular weight for the polymers of Examples 5-7.

[0010] Figure 5 The graph shows the logarithmic tensile viscosity (tensile viscosity versus shear rate) of the polymer in Example 1 at 150°C. Figure 6 This is a logarithmic stretching viscosity graph of the polymer in Example 2.

[0011] definition

[0012] To more clearly define the terms used herein, the following definitions are provided. Unless otherwise specified, the following definitions apply to this disclosure. If a term is used in this disclosure but is not specifically defined herein, the definition in IUPAC Compendium of Chemical Terminology, 2nd Edition (1997) may be applied, provided that the definition does not conflict with any other disclosure or definition applied herein, or render any claim to which the definition applies uncertain or invalid. If any definition or usage provided in any document incorporated herein by reference conflicts with the definition or usage provided herein, the definition or usage provided herein shall prevail.

[0013] In this document, the features of the subject matter are described such that combinations of different features are conceivable within a particular aspect. For each aspect and / or feature disclosed herein, all combinations that will not adversely affect the compositions and processes described herein are considered, with or without an explicit description of a particular combination. Furthermore, unless expressly stated otherwise, any aspect and / or feature disclosed herein may be combined to describe inventive compositions and processes consistent with this disclosure.

[0014] In this disclosure, although compositions and processes are generally described as “comprising” various components or steps, unless otherwise stated, compositions and processes may also be “substantially composed of various components or steps” or “consisting of various components or steps”.

[0015] The terms “a / an” and “described” are intended to include plural alternatives, such as at least one / an. For example, unless otherwise stated, the disclosure of “polymerization reactor” or “metallocene compound” is intended to cover one polymerization reactor or metallocene compound or a combination of more than one polymerization reactor or metallocene compound.

[0016] For any particular compound or group disclosed herein, unless otherwise stated, any name or structure presented (generally or specifically) is intended to cover all conformational isomers, regio isomers, stereoisomers, and mixtures thereof that can be produced by a particular set of substituents. Unless otherwise stated, the name or structure (generally or specifically) also covers all enantiomers, diastereomers, and other optical isomers (if any), whether enantiomers or racemic forms, and mixtures of stereoisomers, as known to those skilled in the art. For example, general references to pentane include n-pentane, 2-methylbutane, and 2,2-dimethylpropane; and general references to butyl include n-butyl, sec-butyl, isobutyl, and tert-butyl.

[0017] Whenever used in this specification and claims, the term "hydrocarbon" refers to a compound containing only carbon and hydrogen. The term "hydrocarbon group" is used herein according to the definition provided by IUPAC: a monovalent group (i.e., a group containing only carbon and hydrogen) formed by removing a hydrogen atom from a hydrocarbon. Non-limiting examples of hydrocarbon groups include alkyl, alkenyl, aryl, and aralkyl groups, etc.

[0018] The term "polymer" is generally used herein to include olefin homopolymers, copolymers, terpolymers, etc., as well as alloys and blends thereof. The term "polymer" also includes impact, block, graft, random, and alternating copolymers. Copolymers can be derived from an olefin monomer and an olefin comonomer, while terpolymers can be derived from an olefin monomer and two olefin comonomers. Therefore, "polymer" encompasses both copolymers and terpolymers. Similarly, the scope of the term "polymerization" includes homopolymers, copolymers, and trimers. Therefore, ethylene polymers will include ethylene homopolymers, ethylene copolymers (e.g., ethylene / α-olefin copolymers), ethylene terpolymers, etc., as well as blends or mixtures thereof. Therefore, ethylene polymers encompass polymers commonly referred to in the art as LLDPE (linear low-density polyethylene) and HDPE (high-density polyethylene). As an example, ethylene copolymers can be derived from ethylene and comonomers such as 1-butene, 1-hexene, or 1-octene. If the monomer and comonomer are ethylene and 1-hexene, respectively, the resulting polymer can be classified as an ethylene / 1-hexene copolymer. The term "polymer" also includes all possible geometries, including isotactic, synisotactic, and random symmetries, if present and unless otherwise stated. The term "polymer" is also intended to include polymers of all molecular weights.

[0019] The terms “catalyst composition,” “catalyst mixture,” “catalyst system,” etc., do not depend on the actual products or compositions produced by the contact or reaction of the initial components of the disclosed or claimed catalyst composition / mixture / system, the nature of the active catalytic sites, or the fate of the organoaluminum compound, metallocene compound, or activator-support after combining these components. Therefore, the terms “catalyst composition,” “catalyst mixture,” “catalyst system,” etc., encompass the initial starting components of the composition, and any products that may be produced by contacting these initial starting components, including both heterogeneous and homogeneous catalyst systems or compositions. The terms “catalyst composition,” “catalyst mixture,” “catalyst system,” etc., are used interchangeably throughout this disclosure.

[0020] Unless otherwise stated, the term "contact" is used herein to describe compositions and processes in which components are contacted or combined together in any order, in any manner, and for any duration. For example, components may be combined by blending or mixing, or by using any suitable technique.

[0021] This document discloses various numerical ranges. Unless otherwise stated, when any type of range is disclosed or claimed, it is intended to individually disclose or claim every possible number that such range can reasonably cover, including the endpoints of the range and any sub-ranges and combinations thereof covered therein. As a representative example, this disclosure states that the weight ratio of the metallocene compound to the activator-support in the catalyst composition can be within a certain range. The disclosure of weight ratios ranging from 1:1 to 1:100,000 is intended to state that any ratio within this range can be, and may include, for example, any range or combination of ranges such as 1:1 to 1:100,000, 1:10 to 1:10,000, 1:20 to 1:1000, or 1:50 to 1:500, etc. Similarly, all other ranges disclosed herein should be interpreted in a manner similar to this example.

[0022] Generally, quantities, sizes, formulations, parameters, ranges, or other quantities or characteristics are expressed as “about” or “approximately”, whether or not explicitly stated. Claims include equivalents of quantities or characteristics, regardless of whether they are modified by the terms “about” or “approximately”.

[0023] Although any methods, apparatus, and materials similar to or equivalent to those described herein may be used in the practice or testing of this invention, typical methods, apparatus, and materials are described herein.

[0024] All publications and patents mentioned herein are incorporated herein by reference in their entirety for the purpose of describing and disclosing, for example, the constructs and methods described in the publications and patents, which may be used in conjunction with the inventions described herein. Detailed Implementation

[0025] This document discloses catalyst compositions comprising metallocene compounds, organoaluminum compounds, a first (high LCB) activator-support, and a second (low LCB) activator-support. Polymerization processes using these catalyst compositions are also disclosed.

[0026] The advantageous and unexpected benefit of the methods / processes and catalyst compositions disclosed herein is the ability to control the long-chain branching (LCB) content of the polymers produced using the catalyst compositions without altering the metallocene composition of the catalyst system. Alternatively, the LCB content of the polymer can be easily changed or adjusted by varying the relative amounts of a first (high LCB) activator-support and a second (low LCB) activator-support in the catalyst composition.

[0027] LCB content is an important property of ethylene-based polymers such as LLDPE and HDPE. Depending on the polymer's end-use application and the manufacturing process used to convert the polymer, a high or low LCB may be required. For example, minimizing the LCB content of thin-gauge film resins to improve the tear resistance and toughness of the film product may be beneficial. However, in other applications, higher levels of LCB are needed to improve melt strength, die swell, and necking during polymer processing (such as blow molding or extrusion coating).

[0028] Catalyst composition and polymerization process

[0029] In one aspect of the invention, a catalyst composition is provided, and such a catalyst composition may comprise (i) a first activator-support comprising a fluorinated solid oxide, (ii) a second activator-support comprising a sulfated solid oxide, (iii) a metallocene compound, and (iv) an organoaluminum compound. In this disclosure, the first activator-support is generally referred to as a “high LCB” activator-support, and the second activator-support is generally referred to as a “low LCB” activator-support. As described herein, given the same other metallocene and organoaluminum components in the catalyst composition, some activator-supports may produce polymers with high (or relatively high) levels of LCB, while others may produce polymers with low (or relatively low) levels of LCB.

[0030] Suitable activators-carriers for fluorinated and sulfated solid oxides, and methods for their preparation, are disclosed, for example, in U.S. Patent Nos. 7,294,599, 7,601,665, 7,884,163, 8,309,485, 8,623,973, and 8,703,886. Generally, solid oxides can encompass oxide materials such as alumina, their “mixed oxides” such as silica-alumina, coatings of one oxide on another, and combinations and mixtures thereof. Mixed oxides such as silica-alumina can be single or multiple chemical phases, wherein more than one metal is combined with oxygen to form a solid oxide. Examples of single or combined mixed oxides that can be used to form activator-carriers include, but are not limited to, silica-alumina, silica-titanium dioxide, silica-zirconia, alumina-titanium dioxide, alumina-zirconia, zinc aluminate, alumina-boron oxide, silica-boron oxide, aluminum phosphate-silica, titanium dioxide-zirconia, etc. The solid oxides used herein may also include oxide materials, such as silica-coated alumina, as described in U.S. Patent No. 7,884,163.

[0031] Therefore, in one aspect, solid oxides may include silica, alumina, silica-alumina, silica-coated alumina, aluminum phosphate, aluminum phosphate, heteropolytungstate, titanium dioxide, silica-titanium dioxide, zirconium oxide, silica-zirconium oxide, magnesium oxide, boron oxide, zinc oxide, any mixed oxides thereof, or any combination thereof. In another aspect, solid oxides may include alumina, silica-alumina, silica-coated alumina, aluminum phosphate, aluminum phosphate, heteropolytungstate, titanium dioxide, silica-titanium dioxide, zirconium oxide, silica-zirconium oxide, magnesium oxide, boron oxide, or zinc oxide, and any mixed oxides thereof, or any mixture thereof. In yet another aspect, solid oxides may include silica, alumina, titanium dioxide, zirconium oxide, magnesium oxide, boron oxide, zinc oxide, any mixed oxides thereof, or any combination thereof. In another aspect, the solid oxide may include silica-alumina, silica-coated alumina, silica-titanium dioxide, silica-zirconium oxide, alumina-boron oxide, or any combination thereof. In another aspect, the solid oxide may include alumina, silica-alumina, silica-coated alumina, or any mixture thereof; alternatively, alumina; alternatively, silica-alumina; or alternatively, silica-coated alumina.

[0032] The usable silica-alumina or silica-coated alumina solid oxide materials can have a silica content of 5% to 95% by weight. On one hand, the silica content of these solid oxides can be 10% to 80% by weight, or 20% to 70% by weight. On the other hand, such materials can have a silica content in the range of 15% to 60% by weight, or 25% to 50% by weight. The solid oxides considered herein can have any suitable surface area, pore volume, and particle size, as will be appreciated by those skilled in the art.

[0033] The activator-carrier may typically contain 1% to 30% by weight of an electron-withdrawing anion (e.g., fluoride or sulfate) based on the weight of the activator-carrier. In the specific aspects provided herein, the activator-carrier may contain 2% to 20% by weight, 2% to 15% by weight, 2% to 10% by weight, 3% to 18% by weight, 3% to 15% by weight, or 3% to 10% by weight of an electron-withdrawing anion (e.g., fluoride or sulfate) based on the total weight of the activator-carrier.

[0034] Typically, the first activator-carrier may comprise fluorinated alumina, fluorinated silica-alumina, fluorinated silica-zirconia, fluorinated silica-titanium dioxide, fluorinated silica-coated alumina, or fluorinated-chlorinated silica-coated alumina, and any mixture or combination thereof. Alternatively or concurrently, the second activator-carrier may comprise sulfated alumina, sulfated silica-alumina, sulfated silica-zirconia, or sulfated silica-coated alumina, and any mixture or combination thereof.

[0035] In another aspect, the catalyst composition consistent with the present invention may comprise (i) a first activator-support comprising alumina coated with fluorinated silica, (ii) a second activator-support comprising sulfated bentonite and / or sulfated alumina, (iii) a metallocene compound, and (iv) an organoaluminum compound. Thus, the second activator-support may comprise sulfated bentonite; alternatively, the second activator-support may comprise sulfated alumina; or alternatively, the second activator-support may comprise both sulfated bentonite and sulfated alumina.

[0036] Similar to sulfated solid oxides such as sulfated alumina, sulfated bentonite is also a suitable second activator-carrier or a suitable low-LCB activator-carrier. As those skilled in the art will recognize, bentonite can have any surface area, pore volume, and particle size characteristics suitable for olefin-based polymerization processes, and sulfated bentonite can be prepared by any typical procedure such as that described in U.S. Patent No. 2,470,872. Sulfated bentonite is an acidic clay and is generally referred to as acid bentonite or acid-treated bentonite. Typically, sulfated bentonite is sulfuric acid-washed bentonite (or montmorillonite), as described in U.S. Patent No. 2,470,872. Suitable sulfated bentonite typically has a residual acidity value of 3 to 14 (mg KOH / g at the phenolphthalein endpoint) and approximately 3-6 wt% Ca, 28-32 wt% Si, 0.08-0.14 wt% Na, 0.1-0.3 wt% Sr, 2.8-4.8 wt% S, and 0.5-0.75 wt% Ti (via XRF).

[0037] Consistent with aspects of the present invention, the catalyst composition may contain one or more metallocene compounds and one or more organoaluminum compounds. Furthermore, the catalyst composition can be prepared by contacting the components of the catalyst composition (first activator-support, second activator-support, metallocene compound, and organoaluminum compound) in any order or sequence. Typically, the organoaluminum compound, the first "high LCB" activator-support, and the second "low LCB" activator-support are first contacted or combined for a suitable time, followed by contacting the metallocene compound to form the catalyst composition. However, the organoaluminum compound, the first "high LCB" activator-support, the second "low LCB" activator-support, and the metallocene compound may also be contacted or combined substantially simultaneously to form the catalyst composition.

[0038] In one aspect, a first polymerization process consistent with the present invention may include, in a polymerization reactor system, contacting a catalyst composition (any catalyst composition disclosed herein containing a first activator-support, a second activator-support, a metallocene compound, and an organoaluminum compound) with ethylene and optionally an olefin comonomer under polymerization conditions to produce an ethylene polymer.

[0039] On the other hand, a second polymerization process consistent with the present invention (also referred to as a method for controlling LCB content) may include (a) contacting a metallocene compound, an organoaluminum compound, a first (high LCB) activator-support, and a second (low LCB) activator-support to form a catalyst composition, (b) in a polymerization reactor system, contacting the catalyst composition with ethylene and optionally an olefin comonomer under polymerization conditions to produce an ethylene polymer having a long-chain branching (LCB) content, and (c) controlling the relative amounts of the first (high LCB) activator-support and the second (low LCB) activator-support in the catalyst composition in step (a) to adjust the LCB content of the ethylene polymer. Therefore, in step (c), the LCB content of the ethylene polymer produced by the process can be controlled or changed by controlling or altering the relative amounts of the high LCB activator-support and the low LCB activator-support used in the catalyst composition.

[0040] Step (a) of this second polymerization process can be performed by pre-contacting the organoaluminum compound, the first (high LCB) activator-support, and the second (low LCB) activator-support for a suitable time, followed by contacting the metallocene compound to form a catalyst composition. However, step (a) is not limited to this, and in some aspects, step (a) may include contacting the organoaluminum compound, the first (high LCB) activator-support, the second (low LCB) activator-support, and the metallocene compound substantially simultaneously to form a catalyst composition. Additionally, while not limited to this, the catalyst composition in step (a) can be conveniently prepared by feeding the high LCB activator-support and the low LCB activator-support separately (e.g., in separate feed streams) into a vessel and mixing them with the metallocene compound and the organoaluminum compound to form a catalyst composition, and then feeding this mixture into a reactor in a polymerization reactor system.

[0041] In one aspect of the second polymerization process, the first (high LCB) activator-support may comprise a fluorinated solid oxide, while the second (low LCB) activator-support may comprise a sulfated solid oxide. Any suitable fluorinated solid oxide and sulfated solid oxide, or any fluorinated solid oxide and sulfated solid oxide disclosed herein, may be used. In another aspect, the first (high LCB) activator-support may comprise alumina coated with fluorinated silica, and the second (low LCB) activator-support may comprise sulfated bentonite and / or sulfated alumina. Thus, the second activator-support may comprise sulfated bentonite; alternatively, the second activator-support may comprise sulfated alumina; or alternatively, the second activator-support may comprise both sulfated bentonite and sulfated alumina.

[0042] Optionally, the first and second polymerization processes may further include determining (or measuring) the LCB content of the ethylene polymer, and adjusting the relative amounts of a first (high LCB) activator-support and a second (low LCB) activator-support in the catalyst composition based on the difference between the measured LCB content and a target LCB content. Thus, for example, if the LCB content of the ethylene polymer is lower than the desired target LCB content, the ratio of the high LCB activator-support to the low LCB activator-support in the catalyst composition can be increased, thereby increasing the LCB content of the ethylene polymer.

[0043] Depending on the required amount of LCB, any suitable weight ratio of the first activator-support to the second activator-support in the catalyst composition and polymerization process can be used. Typical weight ratios of the first activator-support to the second activator-support may include 100:1 to 1:100, 10:1 to 1:10, 5:1 to 1:5, 2:1 to 1:2, or 1.5:1 to 1:1.5, etc.

[0044] In both the first and second polymerization processes, the LCB content of the ethylene polymer is not particularly limited and is often determined based on considerations of the manufacturing process and the final product performance for the end-use application of the ethylene polymer. However, ethylene polymers can typically contain 1 to 150 LCBs per million total carbon atoms, such as 1 to 10 LCBs, 10 to 150 LCBs, or 15 to 100 LCBs per million total carbon atoms. This LCB content is determined using the Janzen-Colby method.

[0045] Typically, in the catalyst compositions and polymerization processes disclosed herein, the molar ratio of the organoaluminum compound to the metallocene compound can range from 1:1 to 1000:1, such as 1:1 to 100:1, 2:1 to 200:1, or 5:1 to 100:1, but is not limited thereto. If more than one organoaluminum compound and / or more than one metallocene compound are used, this ratio is based on the total molar number of each of the respective types of components.

[0046] The weight ratio of the metallocene compound to the activator-carrier can range from 1:1 to 1:100,000 on one hand, from 1:10 to 1:10,000 on another, from 1:20 to 1:1000 on another, and from 1:50 to 1:500 on yet another. Additionally, the weight ratio of the activator-carrier to the organoaluminum compound can range from 100:1 to 1:100 on one hand, from 10:1 to 1:10 on another, from 5:1 to 1:5 on another, and from 2:1 to 1:2 on yet another. If two or more of these components are present, these ratios are based on the total weight of the respective types of components.

[0047] In some aspects, the catalyst compositions used in polymerization processes are substantially free of aluminoxane compounds, organoboron or organoborate compounds, ionized compounds, and / or other similar materials; alternatively, they are substantially free of aluminoxanes; alternatively, they are substantially free of organoboron or organoborate compounds; or alternatively, they are substantially free of ionized compounds. In these aspects, the catalyst compositions exhibit catalytic activity in the absence of these additional materials. For example, the catalyst compositions of the present invention may consist substantially of a metallocene compound, an organoaluminum compound, a first (high LCB) activator-support, and a second (low LCB) activator-support, wherein no other materials are present in the catalyst composition that would increase / decrease the catalytic activity of the catalyst composition by more than about 10% compared to the catalyst composition without said materials.

[0048] Regarding the first and second polymerization processes, a "polymerization reactor" includes any polymerization reactor capable of polymerizing olefin monomers and comonomers (one or more comonomers) to produce homopolymers, copolymers, terpolymers, etc. Various types of polymerization reactors include those that may be called batch reactors, slurry reactors, gas-phase reactors, solution reactors, high-pressure reactors, tubular reactors, autoclave reactors, etc., or combinations thereof; or alternatively, polymerization reactor systems may include slurry reactors, gas-phase reactors, solution reactors, or combinations thereof. The polymerization conditions for various reactor types are well known to those skilled in the art. Gas-phase reactors may include fluidized bed reactors or staged horizontal reactors. Slurry reactors may include vertical and / or horizontal circulation. High-pressure reactors may include autoclaves and / or tubular reactors. Reactor types may include batch or continuous processes. Continuous processes may use batch and / or continuous product discharge. Polymerization reactor systems and processes may also include partial or complete direct recycling of unreacted monomers, unreacted comonomers, and / or diluents.

[0049] Polymerization reactor systems may include a single reactor or multiple reactors of the same or different types (two reactors, more than two reactors, etc.). For example, a polymerization reactor system may include a slurry reactor, a gas-phase reactor, a solution reactor, or a combination of two or more of these reactors. Polymer production in multiple reactors may include several stages in at least two separate polymerization reactors interconnected by transfer devices, making it possible to transfer polymer obtained from a first polymerization reactor to a second reactor. The polymerization conditions required in one of the reactors may differ from the operating conditions of the other reactors. Alternatively, polymerization in multiple reactors may include manually transferring polymer from one reactor to a subsequent reactor to continue polymerization. Multi-reactor systems may include any combination, including but not limited to multiple circulating reactors, multiple gas-phase reactors, a combination of circulating and gas-phase reactors, multiple high-pressure reactors, or a combination of high-pressure reactors with circulating and / or gas-phase reactors. Multiple reactors may be connected in series, in parallel, or in series and in parallel operation. Therefore, the present invention covers polymerization reactor systems including a single reactor, including two reactors, and including more than two reactors. In some aspects of the invention, a polymerization reactor system may include a slurry reactor, a gas-phase reactor, a solution reactor, and multiple reactor combinations thereof.

[0050] According to one aspect, the polymerization reactor system may include at least one circulating slurry reactor comprising vertical or horizontal circulation. Monomers, diluents, catalysts, and comonomers may be continuously fed into the circulating reactor where polymerization occurs. Typically, a continuous process may include the continuous introduction of monomers / comonomers, catalysts, and diluents into the polymerization reactor, and the continuous removal of a suspension containing polymer particles and diluents from the reactor. The reactor effluent may be flashed to remove solid polymers from the liquid containing diluents, monomers, and / or comonomers. Various techniques may be used for this separation step, including but not limited to flash evaporation, which may include any combination of heating and depressurization, separation by cyclone action in a cyclone separator or hydrocyclone, or separation by centrifugation.

[0051] Typical slurry polymerization processes (also known as particle formation processes) are disclosed, for example, in U.S. Patent Nos. 3,248,179, 4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, 6,833,415 and 8,822,608.

[0052] Suitable diluents used in slurry polymerization include, but are not limited to, the monomers being polymerized and hydrocarbons that are liquid under reaction conditions. Examples of suitable diluents include, but are not limited to, hydrocarbons such as propane, cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, and n-hexane. Some cyclic polymerization reactions can occur under bulk conditions without the use of diluents.

[0053] According to another aspect, the polymerization reactor system may include at least one gas-phase reactor (e.g., a fluidized bed reactor). Such reactor systems may employ a continuous recycle stream containing one or more monomers, which continuously circulates through a fluidized bed under polymerization conditions in the presence of a catalyst. The recycle stream can be discharged from the fluidized bed and recycled back into the reactor. Simultaneously, polymer products can be discharged from the reactor, and new or fresh monomers can be added to replace the monomers polymerized. Such gas-phase reactors may include processes for multi-step gas-phase polymerization of olefins, wherein olefins are polymerized in gas phase in at least two separate gas-phase polymerization zones, while a catalyst-containing polymer formed in the first polymerization zone is fed into a second polymerization zone. Representative gas-phase reactors are disclosed in U.S. Patent Nos. 5,352,749, 4,588,790, 5,436,304, 7,531,606, and 7,598,327.

[0054] According to another approach, the polymerization reactor system may include a high-pressure polymerization reactor, such as a tubular reactor or an autoclave reactor. The tubular reactor may have several zones in which fresh monomers, initiators, or catalysts are added. The monomers may be entrained in an inert gas stream and introduced in one zone of the reactor. The initiator, catalyst, and / or catalyst components may be entrained in the gas stream and introduced in another zone of the reactor. The gas streams may be intermixed for polymerization. Heat and pressure may be appropriately used to obtain optimal polymerization reaction conditions.

[0055] According to another aspect, the polymerization reactor system may include a solution polymerization reactor, in which the monomer / comonomer is contacted with the catalyst composition by suitable stirring or other means. A support containing an inert organic diluent or excess monomer may be used. If necessary, the monomer / comonomer may be contacted with the catalytic reaction products in the gas phase, with or without liquid material. The polymerization zone may be maintained at temperatures and pressures that would allow a polymer solution to form in the reaction medium. Stirring may be used to obtain better temperature control and maintain a homogeneous polymerization mixture throughout the polymerization zone. Appropriate means are used to dissipate the exothermic reaction.

[0056] The polymerization reactor system may also include any combination of at least one feed system, at least one feed system for the catalyst or catalyst components, and / or at least one polymer recovery system. Suitable reactor systems may also include systems for feedstock purification, catalyst storage and preparation, extrusion, reactor cooling, polymer recovery, fractionation, recycling, storage, loading, laboratory analysis, and process control. Depending on the desired properties of the olefin polymer, hydrogen may be added to the polymerization reactor as needed (e.g., continuously, pulsed, etc.).

[0057] Polymerization conditions that can be controlled to improve efficiency and provide desired polymer properties can include temperature, pressure, and the concentrations of various reactants. Polymerization temperature can affect catalyst yield, polymer molecular weight, and molecular weight distribution. For example, to produce a specific grade of olefin polymer (or ethylene polymer), various polymerization conditions can be kept substantially constant. According to the Gibbs free energy equation, a suitable polymerization temperature can be any temperature below the depolymerization temperature. Typically, this includes, for example, 60°C to 280°C, or 60°C to 120°C, depending on the type of polymerization reactor. In some reactor systems, polymerization temperatures are typically in the range of about 70°C to about 100°C or about 75°C to about 95°C.

[0058] The appropriate pressure will also vary depending on the reactor and type of polymerization. Liquid-phase polymerization in a circulating reactor typically involves pressures less than 1000 psig (6.9 MPa). Gas-phase polymerization typically involves pressures of 200 to 500 psig (1.4 MPa to 3.4 MPa). High-pressure polymerization in tubular or autoclave reactors typically occurs at 20,000 to 75,000 psig (138 to 517 MPa). Polymerization reactors can also be operated in the supercritical region, which generally occurs at higher temperatures and pressures. Operation above the critical point (supercritical phase) of the pressure / temperature diagram can provide advantages for the polymerization process.

[0059] The concentration of reactants entering the polymerization reactor can be controlled to produce a resin with certain physical and mechanical properties. The proposed end-use product formed from the polymer resin and the method of forming said product ultimately determine the desired polymer properties and attributes. Mechanical properties include tensile, flexural, impact, creep, stress relaxation, and hardness tests. Physical properties include density, molecular weight, molecular weight distribution, melting temperature, glass transition temperature, crystallization melting temperature, stereoregularity, crack propagation, long-chain branching, and rheological measurements.

[0060] Consistent with aspects of the present invention, the olefin monomer used in the polymerization process is ethylene, and if used, the comonomer may contain C3-C4. 20 α-olefins; alternatively, C3-C 10 α-olefins; alternatively, the comonomer may comprise 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, styrene, or any combination thereof; alternatively, the comonomer may comprise 1-butene, 1-hexene, 1-octene, or any combination thereof; alternatively, the comonomer may comprise 1-butene; alternatively, the comonomer may comprise 1-hexene; or alternatively, the comonomer may comprise 1-octene. Thus, in one aspect, the catalyst composition may be reacted with ethylene and containing C3-C... 10 An olefin comonomer of an α-olefin is contacted to produce an ethylene polymer, while on the other hand, a catalyst composition may be contacted with ethylene and an olefin comonomer comprising 1-butene, 1-hexene, 1-octene or a mixture thereof to produce an ethylene polymer.

[0061] In one aspect, the ethylene polymer of the present invention may include ethylene / α-olefin copolymers; in another aspect, the ethylene polymer may include ethylene homopolymers; and in yet another aspect, the ethylene polymer of the present invention may include both ethylene / α-olefin copolymers and ethylene homopolymers. For example, the ethylene polymer may include ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, ethylene homopolymers, or any combination thereof; alternatively, ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, or any combination thereof; or alternatively, ethylene / 1-hexene copolymers.

[0062] The aspects considered herein also relate to and cover ethylene polymers produced by any polymerization process disclosed herein. Articles may be formed from polymers produced according to the polymerization process described herein, and / or may contain said polymers.

[0063] Metallocene compounds

[0064] The metallocene-based catalyst composition according to the present invention may contain bridged metallocene compounds and / or unbridged metallocene compounds. The metallocene-based catalyst composition according to the present invention may also contain two or more bridged metallocene compounds, two or more unbridged metallocene compounds, or at least one bridged metallocene compound and at least one unbridged metallocene compound. The metallocene compounds may contain, for example, transition metals (one or more) from Groups IIIB-VIIIB of the periodic table. In one aspect, the metallocene compound may contain transition metals from Groups III, IV, V, or VI, or combinations of two or more transition metals. In other aspects, the metallocene compound may contain chromium, titanium, zirconium, hafnium, vanadium, or combinations thereof, or may contain titanium, zirconium, hafnium, or combinations thereof. In other aspects, the metallocene compound may contain titanium, or zirconium, or hafnium, alone or in combination.

[0065] In some aspects of the invention, the metallocene compound may include, for example, bridged metallocene compounds having titanium, zirconium, or hafnium, such as bridged zirconium or hafnium metallocene compounds having a fluorenyl group, or bridged zirconium or hafnium metallocene compounds having a cyclopentadienyl and a fluorenyl group. In some aspects, such bridged metallocenes may contain an alkenyl substituent (e.g., a terminal alkenyl group) on the bridging group and / or on the cyclopentadienyl-type group (e.g., cyclopentadienyl or fluorenyl). In another aspect, the metallocene compound may include a bridged zirconium or hafnium metallocene having a fluorenyl group and an aryl group on the bridging group; alternatively, a bridged zirconium or hafnium metallocene having a cyclopentadienyl group and a fluorenyl group and an aryl group on the bridging group; alternatively, a bridged zirconium-based metallocene having a fluorenyl group and an aryl group on the bridging group; alternatively, a bridged hafnium metallocene having a fluorenyl group and an aryl group on the bridging group; or alternatively, a bridged zirconium or hafnium metallocene having a cyclopentadienyl group and a fluorenyl group and an aryl group on the bridging group. In these and other aspects, the aryl group on the bridging group may be phenyl. Optionally, these bridged metallocenes may contain an alkenyl substituent (e.g., a terminal alkenyl group) on the bridging group and / or on the cyclopentadienyl-type group.

[0066] In some aspects, metallocene compounds may include bridged zirconium or hafnium metallocene compounds having two cyclopentadienyl groups, two indenyl groups, or one cyclopentadienyl group and one indenyl group (e.g., bisindenyl metallocene compounds). Thus, metallocene compounds may include bridged zirconium-based metallocene compounds having two indenyl groups, or alternatively, bridged hafnium metallocene compounds having two indenyl groups. In some aspects, an aryl group may be present on the bridging group, while in other aspects, an aryl group is absent from the bridging group. Optionally, these bridged indenyl metallocenes may contain an alkenyl substituent (e.g., a terminal alkenyl group) on the bridging group and / or on the indenyl group (one or two indenyl groups). The bridging atom of the bridging group may be, for example, a single carbon atom or a single silicon atom; alternatively, the bridge may contain a chain of two carbon atoms, a chain of two silicon atoms, and so on.

[0067] Illustrative and non-limiting examples of bridging metallocene compounds (e.g., having zirconium or hafnium) that can be used in catalyst systems and polymerization processes consistent with aspects of the present invention are described in U.S. Patent Nos. 7,026,494, 7,041,617, 7,226,886, 7,312,283, 7,517,939 and 7,619,047.

[0068] In some aspects of the invention, the metallocene compound may include an unbridged metallocene; alternatively, an unbridged zirconium or hafnium-based metallocene compound and / or an unbridged zirconium and / or hafnium-based binuclear metallocene compound; alternatively, an unbridged zirconium or hafnium-based metallocene compound containing two cyclopentadienyl groups, two indenyl groups, or one cyclopentadienyl group and one indenyl group; alternatively, an unbridged zirconium-based metallocene compound containing two cyclopentadienyl groups, two indenyl groups, or one cyclopentadienyl group and one indenyl group. Illustrative and non-limiting examples of unbridged metallocene compounds (e.g., having zirconium or hafnium) that can be used in catalyst systems and polymerization processes consistent with aspects of the invention are described in U.S. Patent Nos. 7,199,073, 7,226,886, 7,312,283, and 7,619,047.

[0069] Furthermore, metallocene compounds may include unbridged binuclear metallocenes, such as those described in U.S. Patent Nos. 7,919,639 and 8,080,681. Metallocene compounds may include unbridged zirconium and / or hafnium-based binuclear metallocene compounds. For example, metallocene compounds may include unbridged zirconium-based homodinuclear metallocene compounds or unbridged hafnium-based homodinuclear metallocene compounds, or unbridged zirconium and / or hafnium-based heterodinuclear metallocene compounds (i.e., binuclear compounds having two hafnium, or two zirconium, or one zirconium and one hafnium).

[0070] The invention also relates to catalyst compositions and polymerization processes using two or more metallocene compounds, such as bismetallocene catalyst compositions. Independently, each respective metallocene compound may be any bridged metallocene compound disclosed herein or any unbridged metallocene compound disclosed herein. If two metallocene compounds are present in the catalyst composition, the weight ratio (first:second) of the first compound to the second compound is typically in the range of 50:1 to 1:50, 10:1 to 1:10, 5:1 to 1:5, 2:1 to 1:2, 1.5:1 to 1:1.5, or 1.2:1 to 1:1.2.

[0071] In one specific aspect of the invention, the metallocene compound is (1) rac-ethylene-bis(1-indenyl)zirconium dichloride; (2) methyl(buten-3-yl)methylene(η5-cyclopentadien-1-ylidene)(η5-2,7-di-tert-butylfluorene-9-ylidene)zirconium dichloride; and (3) diphenylmethylene[η5-[3-(pent-4-enyl)cyclopentadien-1-ylidene]][η5-(2,7-di-tert-butylfluorene-9-ylidene)]zirconium dichloride Hafnium; (4) (n-butylcyclopentadienyl)(1-allylindenyl)zirconia dichloride; (5) rac-dimethylsilylbis(1-indenyl)zirconia dichloride; or (6) 1-ethylpropylene[(n5-cyclopentadienyl-1-ylidene)(n5-(3-propyl)indenyl-1-ylidene]]zirconia dichloride. As discussed herein, the catalyst composition may contain any suitable relative amounts of one, or two or more, of these metallocene compounds.

[0072] Organoaluminum compounds

[0073] This invention covers a variety of catalyst compositions comprising organoaluminum compounds. As disclosed herein, more than one organoaluminum compound may be used in the catalyst compositions disclosed herein.

[0074] In some respects, any suitable organoaluminum compound can have the formula (R Z )3Al, where each R Z It can independently be an aliphatic group having 1 to 10 carbon atoms. For example, each R Z It can independently be methyl, ethyl, propyl, butyl, hexyl, or isobutyl. In other respects, suitable organoaluminum compounds can have the formula Al(X) 7 ) m (X 8 ) 3-m , where each X 7 Each X can be a hydrocarbon group independently; 8 Independently, it can be an alkoxide or aryl oxide, a halide or a hydride; and m can be 1 to 3, including the endpoints. The term "alkyl group" herein refers to a hydrocarbon group and includes, for example, aryl, alkyl, cycloalkyl, alkenyl, cycloalkenyl, cycloalkenidyl, alkynyl, aralkyl, areneyl, and aralkyl. In one aspect, each X... 7 Independently, it can be any hydrocarbon group having 1 to 18 carbon atoms or 1 to 8 carbon atoms, or an alkyl group having 1 to 10 carbon atoms. For example, in some aspects of the invention, each X 7 It can independently be methyl, ethyl, propyl, n-butyl, sec-butyl, isobutyl, or hexyl, etc. According to another aspect of the invention, each X 8 It can be independently an alkoxide or an aromatic oxide (either having 1 to 18 carbon atoms), a halide, or a hydride. In another aspect of the invention, each X8 It can be independently selected from fluorine and chlorine. In the formula Al(X) 7 ) m (X 8 ) 3-m In this formula, m can be a number from 1 to 3 (inclusive), and typically m can be 3. The value of m is not limited to an integer; therefore, this formula can include sesquihalides or other organoaluminum cluster compounds.

[0075] Examples of organoaluminum compounds that can be used in the catalyst compositions and polymerizations according to the present invention include, but are not limited to, trialkylaluminum compounds, dialkylaluminum halide compounds, dialkylaluminum alkoxide compounds, dialkylaluminum hydride compounds, and combinations thereof. Specific non-limiting examples may include trimethylaluminum (TMA), triethylaluminum (TEA), tri-n-propylaluminum (TNPA), tri-n-butylaluminum (TNBA), triisobutylaluminum (TIBA), tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride, ethoxydiethylaluminum, diethylaluminum chloride, etc., or combinations thereof.

[0076] Example

[0077] The present invention is further illustrated by the following embodiments, which should not be construed as limiting the scope of the invention in any way. Various other aspects, modifications, and equivalents will arise in those skilled in the art upon reading this description without departing from the spirit of the invention or the scope of the appended claims.

[0078] The metallocene compounds used in the examples are abbreviated as follows: MET-A is dimethylsilylbis(1-indenyl)zirconia dichloride; MET-B is 1-ethylpropylene[(η5-cyclopentadien-1-ylidene)(η5-(3-propyl)inden-1-ylidene]]zirconia dichloride; and MET-C is methyl(buten-3-yl)methylene(η5-cyclopentadienyl)(η5-2,7-di-tert-butylfluorene-9-ylidene)zirconia dichloride. It is generally believed that MET-A produces polymers with a high amount of LCB, while it is generally believed that MET-B produces relatively low molecular weight polymers with minimal LCB content. It is also generally believed that MET-C produces polymers with a low amount of LCB. The formulations of the activator-carrier used in the examples and their abbreviations are provided below.

[0079] AS-1 is a fluorinated silica-coated alumina prepared by first dissolving ammonium bifluoride (1.5 g) in 50 mL of methanol. Then, 15 g of silica-coated alumina (40 wt% alumina, 450 mL) was... 2The powder (with a surface area of ​​ / g, pore volume of 1.3mL / g, and an average particle size of 35μm) was impregnated with a methanol solution under stirring to produce the consistency of wet sand. After drying overnight in a vacuum at 100°C, the dry powder was passed through a 35-mesh sieve to break up any lumps or clumps. Calcination was performed at 600°C by fluidizing the powder in dry air for 3 hours, followed by cooling to room temperature while fluidizing under nitrogen.

[0080] AS-2 is a sulfated bentonite carrier (Delta Industries Z130, 60 microns average particle size, also supplied under the name F-30X, with residual acidity of 3-6 mg KOH / g at the phenolphthalein endpoint, approximately 5.4 wt% Ca, 29.2 wt% Si, 0.08 wt% Na, 0.27 wt% Sr, 4.1 wt% S, and 0.64 wt% Ti (via XRF)). The base material was heat-treated by placing 21.2 g of the carrier in a thin layer in an aluminum pan and then placing it in a furnace at 280°C for 1.5 hours under dry nitrogen. After removal from the furnace, the heat-treated AS-2 was quickly placed in a bottle under nitrogen and capped.

[0081] AS-3 is produced by first mixing 400 mL of water and 100 g of silica-coated alumina (40% by weight alumina, 450 mL of silica). 2 Fluorinated silica-coated alumina was prepared by measuring a surface area of ​​1.3 mL / g, a pore volume of 1.3 mL / g, and an average particle size of 35 μm. A concentrated hydrofluoric acid (5 g HF) solution was mixed into the slurry, and the resulting slurry was then spray-dried into a dry, flowable powder. Calcination was performed at 600 °C by fluidizing the fluorinated silica-coated alumina (4.75 wt% fluoride) in dry nitrogen for 3 hours, followed by cooling to room temperature while still fluidizing under nitrogen.

[0082] AS-4 is produced by first calcining alumina (300m³) in air at 600°C. 2 Alumina sulfate was prepared by immersing 100 g of alumina in 300 mL of water containing 15 g of concentrated sulfuric acid for 15 min, with a surface area of ​​1 g / g, a pore volume of 1.3 mL / g, and an average particle size of 100 μm. The resulting wet powder was then dried overnight under vacuum at 100 °C. Calcination was performed at 600 °C by fluidizing the alumina sulfate (14.7 wt% sulfate) in dry nitrogen for 3 hr, followed by cooling to room temperature while still fluidizing under nitrogen.

[0083] Melt index (MI, g / 10 min) was determined according to ASTM D1238 using 2,160 g weight at 190°C, and high load melt index (HLMI, g / 10 min) was determined according to ASTM D1238 using 21,600 g weight at 190°C. Melt index was also determined according to ASTM D1505 and ASTM D4703, in g / cm³, on compression-molded samples cooled at 15°C per minute and conditioned at room temperature for 40 hours. 3 Density is determined using units of 1 / 2.

[0084] Molecular weight and molecular weight distribution were obtained using a PL-GPC 220 system (Polymer Labs, Agilent Company) equipped with an IR4 detector (Polymer Char, Spain) and three (3) Styragel HMW-6E GPC columns (Waters, MA) operating at 145 °C. The mobile phase of 1,2,4-trichlorobenzene (TCB) containing 0.5 g / L 2,6-di-tert-butyl-4-methylphenol (BHT) was set at a flow rate of 1 mL / min, and the polymer solution concentration ranged from 0.5 to 1.0 mg / mL depending on the molecular weight. Sample preparation was performed at 150 °C for approximately 4 hours with occasional gentle stirring before transferring the solution to sample vials for injection. Injection volumes of approximately 400 μL were used. Molecular weight and molecular weight distribution were derived using an integral calibration method with Chevron Phillips Chemical Company's HDPE polyethylene resin MARLEX BHB5003 as a standard. The standard integration table is predetermined in a separate experiment using SEC-MALS. Mn is the number-average molecular weight, Mw is the weight-average molecular weight, Mz is the z-average molecular weight, and Mp is the peak molecular weight (the position of the highest point of the molecular weight distribution curve).

[0085] Melt rheological characterization was performed as follows. Small strain (10%) oscillatory shear measurements were conducted on an Anton Paar MCR 501 rheometer using a parallel plate geometry. All rheological tests were performed at 190°C. Next, a modified three-parameter Carreau-Yasuda (CY) empirical model was used to curve-fit the complex viscosity |η*| against frequency (ω) data to obtain the zero-shear viscosity – η0 and the characteristic viscous relaxation time – τ. η And the width parameter –a (CY-a parameter). The simplified Carreau-Yasuda (CY) empirical model is as follows.

[0086]

[0087] Where: |η*(ω)| = the magnitude of complex shear viscosity;

[0088] η0 = zero shear viscosity;

[0089] τ η = Viscous relaxation time (τ(η), in seconds);

[0090] a = "width" parameter (CY-a parameter);

[0091] n = fixed final power law slope (fixed at 2 / 11); and

[0092] ω = angular frequency of oscillatory shear deformation.

[0093] Detailed information on the meaning and interpretation of the CY model and derived parameters can be found in: CA Hieber and HH Chiang, Rheol. Acta, 28, 321 (1989); CA Hieber and HH Chiang, Polym. Eng. Sci., 32, 931 (1992); and RB Bird, R. C. Armstrong and O. Hasseger, Dynamics of Polymeric Liquids, Vol. 1, Fluid Mechanics, 2nd ed., John Wiley & Sons (1987).

[0094] Using the method of Janzen and Colby (J.Mol.Struct.,485 / 486,569-584 (1999), the long chain branching (LCB) per 1,000,000 total carbon atoms in the whole polymer was calculated based on the value of zero shear viscosity (η0) (determined by the Carreau-Yasuda model described above) and the value of Mw obtained using the GPC procedure described above.

[0095] Tensile viscosity was measured using a tensile viscosity fixture and a Sentimanat tensile rheometer (SER-3 universal testing platform, Xpansion Instruments) on a rotational rheometer (Physica MCR-500, Anton Paar). The SER accessory makes it easy to measure instantaneous tensile viscosity as a function of time.

[0096] Test samples were prepared by compression molding at 182°C. The aggregated sample was melted under relatively low pressure for 1 minute, followed by high molding pressure for 2 minutes. The hot press was then shut off for slow cooling. The cooled plate was removed from the press the next day. Rectangular strips with dimensions of 12.77 × 18 mm were cut from the molding plate, and the thickness of the samples was measured.

[0097] The SER testing platform has two drums rotating in opposite directions (MLSentmanat, "Miniature universal testing platform: from extensional melt rheology to solid-state deformation behavior," Rheol. Acta 43, 657 (2004); MLSentmanat, BN Wang, GH. McKinley, "Measuring the transient extensional rheology of polyethylene melts using the SER universal testing platform," J. Rheol. 49, 585 (2005)). The rectangular sample was tested as follows: the rectangular sample was clamped on the two pillars of the fixture, and then the oven was closed to heat to 150°C, where it was annealed at 150°C for 30 seconds to allow the temperature to reach equilibrium. Then, at 150°C... 0.03 and 25s -1 The sample was stretched at a constant Hencky strain rate between rotating drums F. A rotational rheometer recorded the torque M generated by the tangential tensile force between the rotating drums F and F.

[0098] M(t)=2RF(t) (A)

[0099] The drum radius R = 5.155 mm. The Hencky strain rate at a constant drum rotation speed Ω. for

[0100]

[0101] The length of the tension zone between the rotating drums is L = 12.72 mm. For a given Hencky strain rate, the instantaneous tensile viscosity is obtained. for

[0102]

[0103] Where A(t,T) is the cross-sectional area of ​​the sample, which expands thermally during melting and decreases exponentially with stretching:

[0104]

[0105] Where A0 and ρ sThis represents the initial cross-sectional area and the density of the sample measured in the solid state at room temperature. The melt density ρ(T) is derived from ρ(T) = ρ0 - Δρ(T - 273.15)T. Therefore, the instantaneous tensile viscosity as a function of time... Calculated at each stretching rate

[0106]

[0107] Where M 偏移 This is a preset torque that can be applied before actual testing. To compare the tensile response with the linear viscoelastic (LVE) limit, the LVE envelope 3η was obtained from the relaxation time spectrum of dynamic frequency scan data measured at 150°C. + (t)

[0108]

[0109] Among them G i and λ i The set defines the relaxation time spectrum of the material.

[0110] Generally, it has been observed that when long-chain branching exists in a polymer, the instantaneous tensile viscosity deviates sharply from the LVE due to the increased slope before fracture. This behavior is called strain hardening. Conversely, for linear resins, according to Troutton's law, when the LVE envelope (3η) continues to be followed... + At (t) time, the instantaneous tensile viscosity growth curve did not show strain hardening.

[0111] Examples 1-10

[0112] The polymerization experiments of Examples 1-10 are summarized in Tables I-III and were conducted in a 1-gallon stainless steel autoclave reactor containing isobutane as a diluent for 17 to 39 minutes (to produce approximately 210-260 g of polymer). First, the activator-carrier was added to the reactor, followed by TIBA (triisobutylaluminum, 1M in hexane). Then, a toluene solution of the desired metallocene (1 mg / mL) was added, and the reactor was sealed and 2 L of isobutane was added. The reactor contents were heated to the target polymerization temperature of 83°C with stirring (approximately 1000 rpm). When the reactor contents reached 6°C below the target temperature, 1-hexene was added while ethylene was added to the reactor to the target pressure (325 psig). No hydrogen was added. Ethylene was fed as needed to maintain the target pressure. Throughout the experiments, the reactor was maintained at the target temperature using an automatic heating-cooling system. After venting, purging, and cooling of the reactor, the resulting polymer product was dried under reduced pressure.

[0113] Table I summarizes the catalyst compositions of Examples 1-7, and Table II summarizes the polymerization conditions, the amount of polymer product, the catalyst activity (grams of polymer per gram of support per hour), and the melt index of the resulting polymer. Table III summarizes the catalyst compositions of Examples 1-4 and 8-10 (160 mg of activator-support and 0.4 mL of 1 M TIBA), and the melt index, Mn, and Mw / Mn ratio of the resulting polymer. Tables II and III demonstrate that, for a given metallocene ratio, the melt index can be varied by changing the relative amounts of AS-1 and AS-2 in the catalyst composition. Advantageously, this can be done while maintaining a generally consistent Mn and without significantly expanding the molecular weight distribution (Mw / Mn ratio).

[0114] Figure 1 and Figure 2 Van Gurp-Palmen diagrams (phase angles relative to absolute values ​​of complex modulus) for Examples 1-4 (dimetallocene) and Examples 5-7 (monocene) are shown respectively, and these examples used AS-1 (fluorinated silica-coated alumina) and / or AS-2 (sulfated bentonite) as activator-support in the catalyst composition. Resins lacking LCB typically approach about 90° at low complex moduli. For resins containing a large amount of LCB, a significant deviation from 90° is observed at low moduli. Figure 2 As shown, the polymers produced using MET-A exhibited a significant decrease in δ at low moduli. The decrease was largest for the polymer produced using 100% AS-1 (Example 7), while virtually no decrease was observed for the polymer produced using 100% AS-2 (Example 5). These results demonstrate the presence of a large LCB in the polymer produced using 100% AS-1, and conversely, a lower LCB in the polymer produced using 100% AS-2. Importantly, the polymer produced using a 50:50 mixture of AS-1 and AS-2 (Example 6) showed a decrease between that exhibited in Examples 5 and 7. Similar results were obtained using the dimetallocene catalyst systems of Examples 1-4, such as... Figure 1 As shown.

[0115] Figure 3 and Figure 4 The Janzen-Colby diagrams are for the corresponding Examples 1-4 (dimetallocene) and Examples 5-7 (monometallocene) using AS-1 (fluorinated silica-coated alumina) and / or AS-2 (sulfated bentonite) as the activator-support in the catalyst composition. Figure 3 In Examples 1-4, the LCB content increased (approximately 7 to 18 LCBs per million total carbon atoms) as the relative amount of AS-1 in the catalyst composition increased. Similarly, Figure 4 The same trend is shown in Examples 5-7, with LCB content ranging from approximately 2 LCBs (AS-2) to >100 LCBs (AS-1) per million total carbon atoms. Therefore, for example, if the LCB content of the ethylene polymer is below the desired level, more AS-1 (high LCB activator-support) relative to AS-2 (low LCB activator-support) can be added to form a catalyst composition, thereby increasing the LCB content of the ethylene polymer.

[0116] Stretch rheology has also been used as a means of determining the presence of LCBs in polymers. For Newtonian fluids, the stretch viscosity ratio will be equal to 3 times the shear viscosity; for Newtonian fluids, η E The / 3η ratio will equal 1. For molten polymers that exhibit strain hardening due to the presence of LCB, η E The ratio / 3η will be greater than 1. Figure 5 and Figure 6 The figures show the tensile viscosity graphs of the polymers from Examples 1 and 2, determined using SER. These graphs illustrate the dependence of strain hardening on the amount of AS-1 used to produce the polymers.

[0117] In summary, these results demonstrate that two different activator-supports produce catalyst systems with different LCB amounts, and that blends of activator-supports produce catalysts that generate polymers with LCB contents between those produced by using either activator-support independently. Therefore, the amount of LCB introduced into the polymer can be changed or adjusted by adjusting the relative amounts of the two activator-supports used in the catalyst composition.

[0118] Examples 11-12

[0119] For Example 11, the catalyst composition was prepared by combining 0.5 mg MET-C (1 mg / mL toluene) with 100 mg AS-3, followed by the addition of 0.4 mmol TIBA (a solution in hexane or heptane). For Example 12, the catalyst composition was prepared by combining 2 mg MET-C (2 mg / mL toluene) with 100 mg AS-4, followed by the addition of 0.6 mmol TIBA (a solution in hexane or heptane).

[0120] The polymerization experiments in Examples 11-12 were conducted similarly to those in Examples 1-10, except that the polymerization reaction time was 30 min, the target polymerization temperature was 90 °C, 1-hexene was not used, and the ethylene pressure was 390 psig for Example 11 and 420 psig for Example 12.

[0121] Table IV summarizes the results of Examples 11-12. Although MET-C produced the least amount of LCB, the polymer of Example 11 (using AS-3, produced from fluorinated silica-coated alumina) had more than twice the LCB content of the polymer of Example 12 (using AS-4, produced from sulfated alumina), while the Mw values ​​were almost identical. Therefore, similar to Examples 1-10, Examples 11-12 demonstrate that two different activator-supports produced catalyst systems with different amounts of LCB, and that the amount of LCB introduced into the polymer can be changed or adjusted by adjusting the relative amounts of the two activator-supports used in the catalyst composition.

[0122] Table I - Examples 1-7.

[0123]

[0124] Table II - Examples 1-7.

[0125]

[0126] Table III - Examples 1-4 and 8-10.

[0127]

[0128] Table IV - Examples 11-12.

[0129]

[0130] The invention has been described above with reference to numerous aspects and specific embodiments. Based on the detailed description above, many variations will occur to those skilled in the art. All such apparent variations are within the full scope of the appended claims. Other aspects of the invention may include, but are not limited to, the following aspects (unless specifically stated otherwise, aspects are described as “comprising”, but alternatively, may be “substantially composed of” or “composed of”):

[0131] Aspect 1. A polymerization process (or method for controlling LCB content), comprising:

[0132] (a) Contacting a metallocene compound, an organoaluminum compound, a first “high LCB” activator-support, and a second “low LCB” activator-support to form a catalyst composition;

[0133] (b) In a polymerization reactor system, a catalyst composition is contacted with ethylene and optionally olefin comonomers under polymerization conditions to produce an ethylene polymer with a long-chain branching (LCB) content; and

[0134] (c) Controlling the relative amounts of the first “high LCB” activator-support and the second “low LCB” activator-support in the catalyst composition in step (a) to adjust (e.g., control or change) the LCB content of the ethylene polymer.

[0135] Aspect 2. The process as defined in Aspect 1, wherein:

[0136] The first "high LCB" activator-carrier contains fluorinated solid oxides; and

[0137] The second “low LCB” activator-carrier contains sulfated solid oxide.

[0138] Aspect 3. The process as defined in Aspect 1, wherein:

[0139] The first "high LCB" activator-carrier contains alumina coated with fluorinated silica; and

[0140] The second “low LCB” activator-carrier contains sulfated bentonite and / or sulfated alumina.

[0141] Aspect 4. A process as defined in any one of Aspects 1-3, wherein step (a) comprises pre-contacting an organoaluminum compound, a first “high LCB” activator-support, and a second “low LCB” activator-support, and then contacting the metallocene compound to form a catalyst composition.

[0142] Aspect 5. A process as defined in any one of Aspects 1-3, wherein step (a) comprises contacting the organoaluminum compound, the first “high LCB” activator-support, the second “low LCB” activator-support, and the metallocene compound substantially simultaneously to form a catalyst composition.

[0143] Aspect 6. A catalyst composition comprising:

[0144] (i) A first activator-carrier comprising a fluorinated solid oxide;

[0145] (ii) A second activator-carrier comprising sulfated solid oxides;

[0146] (iii) Metallocene compounds; and

[0147] (iv) Organoaluminum compounds.

[0148] Aspect 7. A catalyst composition comprising:

[0149] (i) A first activator-carrier comprising alumina coated with fluorinated silica;

[0150] (ii) A second activator-carrier comprising sulfated bentonite and / or sulfated alumina;

[0151] (iii) Metallocene compounds; and

[0152] (iv) Organoaluminum compounds.

[0153] Aspect 8. A process or composition as defined in any of the preceding aspects, wherein the second activator-carrier comprises sulfated bentonite.

[0154] Aspect 9. A process or composition as defined in any of the preceding aspects, wherein the activator-carrier contains 1 to 30 wt%, 2 to 20 wt%, 2 to 15 wt%, 2 to 10 wt%, or 3 to 10 wt% of an electron-withdrawing anion based on the total weight of the respective activator-carrier.

[0155] Aspect 10. A process or composition as defined in any of the preceding aspects, wherein the organoaluminum compound includes any suitable organoaluminum compound, such as trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride, ethoxydiethylaluminum, diethylaluminum chloride, or any combination thereof.

[0156] Aspect 11. A process or composition as defined in any of Aspects 1-10, wherein the metallocene compound includes any suitable bridging metallocene compound or any bridging metallocene compound disclosed herein.

[0157] Aspect 12. A process or composition as defined in any of Aspects 1-11, wherein the metallocene compound comprises a bridged zirconium-based metallocene compound having a fluorene group.

[0158] Aspect 13. A process or composition as defined in any of Aspects 1-11, wherein the metallocene compound comprises a bridged zirconium or hafnium metallocene compound having a cyclopentadienyl and a fluorenyl group.

[0159] Aspect 14. A process or composition as defined in any of Aspects 1-11, wherein the metallocene compound comprises a bridged zirconium or hafnium metallocene compound having an aryl and / or alkenyl group on a fluorenyl group and a bridging group.

[0160] Aspect 15. A process or composition as defined in any one of Aspects 1-11, wherein the metallocene compound comprises a bridged zirconium or hafnium metallocene compound having a cyclopentadienyl and a fluorenyl group, and an aryl and / or alkenyl group on the bridging group.

[0161] Aspect 16. A process or composition as defined in Aspect 14 or 15, wherein the aryl group is phenyl and the alkenyl group is terminal alkenyl.

[0162] Aspect 17. A process or composition as defined in any of Aspects 1-11, wherein the metallocene compound comprises a bridged zirconium or hafnium metallocene compound having two cyclopentadienyl groups, two indenyl groups, or one cyclopentadienyl group and one indenyl group.

[0163] Aspect 18. A process or composition as defined in any of Aspects 1-11, wherein the metallocene compound comprises a bridged zirconium-based metallocene compound having two indenyl groups.

[0164] Aspect 19. A process or composition as defined in any of Aspects 11-18, wherein the bridging group contains a single silicon bridging atom, a single carbon bridging atom, or a chain of two carbon atoms.

[0165] Aspect 20. A process or composition as defined in any of Aspects 1-10, wherein the metallocene compound includes any suitable unbridged metallocene compound or any unbridged metallocene compound disclosed herein.

[0166] Aspect 21. A process or composition as defined in any of Aspects 1-10, wherein the metallocene compound comprises an unbridged zirconium or hafnium metallocene compound containing two cyclopentadienyl groups, two indenyl groups, or one cyclopentadienyl group and one indenyl group.

[0167] Aspect 22. A process or composition as defined in any of Aspects 1-10, wherein the metallocene compound comprises an unbridged zirconium-based metallocene compound containing two cyclopentadienyl groups, two indenyl groups, or one cyclopentadienyl group and one indenyl group.

[0168] Aspect 23. A process or composition as defined in any one of Aspects 1-10, wherein the metallocene compound comprises:

[0169] (1) rac-ethylene-bis(1-indenyl)zirconium dichloride;

[0170] (2) Methyl(buten-3-yl)methylene(η5-cyclopentadien-1-ylidene)(η5-2,7-di-tert-butylfluorene-9-ylidene)zirconium dichloride;

[0171] (3) Diphenylmethylene[η5-[3-(pent-4-enyl)cyclopentadien-1-ylidene]][η5-(2,7-di-tert-butylfluorene-9-ylidene)] hafnium dichloride;

[0172] (4) (n-Butylcyclopentadienyl)(1-allylindenyl)zirconium dichloride;

[0173] (5) rac-dimethylsilylbis(1-indenyl)zirconium dichloride;

[0174] (6) 1-Ethylpropylene[(η5-cyclopentadien-1-ylidene)(η5-(3-propyl)indene-1-ylidene]]zirconium dichloride;

[0175] Or any combination thereof.

[0176] Aspect 24. A process or composition as defined in any of Aspects 1-23, wherein the catalyst composition contains a metallocene compound.

[0177] Aspect 25. A process or composition as defined in any of Aspects 1-23, wherein the catalyst composition contains two or more metallocene compounds.

[0178] Aspect 26. A process or composition as defined in any of the preceding aspects, wherein the weight ratio of the metallocene compound to the activator-carrier is within any suitable range of, for example, 1:1 to 1:100,000, 1:10 to 1:10,000, 1:20 to 1:1000, or 1:50 to 1:500.

[0179] Aspect 27. A process or composition as defined in any of the preceding aspects, wherein the molar ratio of the organoaluminum compound to the metallocene compound is within any suitable range of, for example, 1:1 to 1000:1, 1:1 to 100:1, 2:1 to 200:1 or 5:1 to 100:1.

[0180] Aspect 28. A process or composition as defined in any of the preceding aspects, wherein the weight ratio of the activator-carrier to the organoaluminum compound is within any suitable range, for example, from 100:1 to 1:100, from 10:1 to 1:10, from 5:1 to 1:5 or from 2:1 to 1:2.

[0181] Aspect 29. A process or composition as defined in any of the preceding aspects, wherein the weight ratio of the first activator-carrier to the second activator-carrier is within any suitable range of, for example, 100:1 to 1:100, 10:1 to 1:10, 5:1 to 1:5, 2:1 to 1:2 or 1.5:1 to 1:1.5.

[0182] Aspect 30. A process or composition as defined in any of the preceding aspects, wherein the catalyst composition is substantially free of aluminoxane compounds, organoboron or organoboronate compounds, ionized compounds or combinations thereof.

[0183] Aspect 31. A polymerization process comprising, in a polymerization reactor system, contacting a catalyst composition as defined in any one of aspects 6-30 with ethylene and optionally an olefin comonomer under polymerization conditions to produce an ethylene polymer.

[0184] Aspect 32. The process as defined in any of the preceding aspects, wherein the optional olefin comonomer comprises C3-C 20 α-olefins.

[0185] Aspect 33. The process as defined in any of the preceding aspects, wherein the catalyst composition is reacted with ethylene and C3-C 10 Contact of olefin comonomers of α-olefins.

[0186] Aspect 34. The process as defined in any of the preceding aspects, wherein the catalyst composition is contacted with ethylene and an olefin comonomer comprising 1-butene, 1-hexene, 1-octene or a mixture thereof.

[0187] Aspect 35. A process as defined in any of the preceding aspects, wherein the polymerization reactor system includes a batch reactor, a slurry reactor, a gas-phase reactor, a solution reactor, a high-pressure reactor, a tubular reactor, an autoclave reactor, or a combination thereof.

[0188] Aspect 36. A process as defined in any of the preceding aspects, wherein the polymerization reactor system includes a slurry reactor, a gas-phase reactor, a solution reactor, or a combination thereof.

[0189] Aspect 37. A process as defined in any of the preceding aspects, wherein the polymerization reactor system includes a circulating slurry reactor.

[0190] Aspect 38. A process as defined in any of Aspects 1-37, wherein the polymerization reactor system comprises a single reactor.

[0191] Aspect 39. A process as defined in any of Aspects 1-37, wherein the polymerization reactor system comprises two reactors.

[0192] Aspect 40. A process as defined in any of Aspects 1-37, wherein the polymerization reactor system comprises more than two reactors.

[0193] Aspect 41. The process as defined in any of the preceding aspects, wherein the ethylene polymer includes ethylene homopolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, or any combination thereof.

[0194] Aspect 42. The process as defined in any of the preceding aspects, wherein the ethylene polymer includes an ethylene / 1-hexene copolymer.

[0195] Aspect 43. A process as defined in any of the preceding aspects, wherein the ethylene polymer has any suitable LCB content, for example, 1 to 150 LCBs, 1 to 10 LCBs, 10 to 150 LCBs, or 15 to 100 LCBs per million total carbon atoms.

[0196] Aspect 44. The process as defined in any of the preceding aspects further includes the following steps:

[0197] Determine (or measure) the LCB content of the ethylene polymer; and

[0198] Based on the difference between the measured LCB content and the target LCB content, the relative amounts of the first "high LCB" activator-support and the second "low LCB" activator-support in the catalyst composition are adjusted.

[0199] Aspect 45. An ethylene polymer produced by a process as defined in any of the preceding aspects.

[0200] Aspect 46. An article comprising an ethylene polymer as defined in aspect 45.

Claims

1. A catalyst composition comprising: (i) A first activator-carrier comprising alumina coated with fluorinated silica; (ii) A second activator-carrier containing sulfated bentonite; (iii) Metallocene compounds; (iv) Organoaluminum compounds selected from trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, or triisobutylaluminum; and The weight ratio of the first activator-carrier to the second activator-carrier is in the range of 5:1 to 1:

5.

2. The composition of claim 1, wherein: The weight ratio of the metallocene compound to the activator-carrier is in the range of 1:1 to 1:100,000; and The molar ratio of the organoaluminum compound to the metallocene compound is in the range of 1:1 to 1000:

1.

3. The composition of claim 1, wherein the weight ratio of the first activator-carrier to the second activator-carrier is in the range of 3:1 to 1:

3.

4. The composition of claim 1, wherein the catalyst composition is free from aluminoxane compounds, organoboron or organoboronate compounds, ionized compounds or combinations thereof.

5. The composition of claim 1, wherein the catalyst composition contains two or more metallocene compounds.

6. The composition of claim 1, wherein the metallocene compound comprises: (1) rac -Ethylene-bis(1-indenyl)zirconium dichloride; (2) Methyl(buten-3-yl)methylene(η5-cyclopentadien-1-ylidene)(η5-2,7-di-tert-butylfluorene-9-ylidene)zirconium dichloride; (3) Diphenylmethylene[η5-[3-(pent-4-enyl)cyclopentadien-1-ylidene]][η5-(2,7-di-tert-butylfluorene-9-ylidene)] hafnium dichloride; (4) (n-Butylcyclopentadienyl)(1-allylindenyl)zirconium dichloride; (5) rac- Dimethylsilylbis(1-indenyl)zirconium dichloride; (6) 1-Ethylpropylidene[(η5-cyclopentadien-1-ylidene)(η5-(3-propyl)indene-1-ylidene)]zirconium dichloride; or Any combination thereof.

7. The composition of claim 1, wherein the metallocene compound comprises: Bridged zirconium or hafnium metallocene compounds having cyclopentadienyl and fluorenyl groups; Bridged zirconium-based metallocene compounds containing two cyclopentadienyl groups and two indenyl groups, or one cyclopentadienyl group and one indenyl group; Unbridged zirconium or hafnium metallocene compounds containing two cyclopentadienyl groups and two indenyl groups, or one cyclopentadienyl group and one indenyl group; or Any combination thereof.

8. The composition of claim 1, wherein the molar ratio of the organoaluminum compound to the metallocene compound is in the range of 2:1 to 200:

1.

9. The composition of claim 1, wherein the weight ratio of the activator-carrier to the organoaluminum compound is in the range of 100:1 to 1:

100.

10. The composition of claim 1, wherein the metallocene compound comprises: (1) rac -Ethylene-bis(1-indenyl)zirconium dichloride; and / or (5) rac- Dimethylsilylbis(1-indenyl)zirconium dichloride.

11. The composition of claim 1, wherein the fluorinated silica-coated alumina comprises 2-15% by weight of fluoride.

12. The composition of claim 1, wherein the fluorinated silica-coated alumina comprises 15-60% by weight of silica, based on the weight of the silica-coated alumina.

13. A catalyst composition comprising: (i) A first activator-carrier comprising alumina coated with fluorinated silica; (ii) A second activator-carrier comprising sulfated bentonite, wherein the sulfated bentonite comprises 28-32% by weight of silicon; (iii) Metallocene compounds; (iv) Organoaluminum compounds selected from trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, or triisobutylaluminum; and The weight ratio of the first activator-carrier to the second activator-carrier is in the range of 5:1 to 1:

5.

14. The composition of claim 13, wherein the sulfated bentonite comprises 0.08-0.14% by weight of sodium.

15. The composition of claim 13, wherein the sulfated bentonite comprises 2.8-4.8% by weight of sulfur.

16. The composition of claim 13, wherein the sulfated bentonite is characterized by a residual acidity of 3-14 mg KOH / g.

17. The composition of claim 13, wherein the fluorinated silica-coated alumina comprises 2-15% by weight of fluoride.

18. The composition of claim 13, wherein the fluorinated silica-coated alumina comprises 15-60% by weight of silica, based on the weight of the silica-coated alumina.

19. The composition of claim 13, wherein the metallocene compound comprises: (1) rac -Ethylene-bis(1-indenyl)zirconium dichloride; (2) Methyl(buten-3-yl)methylene(η5-cyclopentadien-1-ylidene)(η5-2,7-di-tert-butylfluorene-9-ylidene)zirconium dichloride; (3) Diphenylmethylene[η5-[3-(pent-4-enyl)cyclopentadien-1-ylidene]][η5-(2,7-di-tert-butylfluorene-9-ylidene)] hafnium dichloride; (4) (n-Butylcyclopentadienyl)(1-allylindenyl)zirconium dichloride; (5) rac- Dimethylsilylbis(1-indenyl)zirconium dichloride; (6) 1-Ethylpropylidene[(η5-cyclopentadien-1-ylidene)(η5-(3-propyl)indene-1-ylidene)]zirconium dichloride; or Any combination thereof.

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