Process for producing propylene-based copolymers with broad CD and MWD

Abstract

A process for producing propylene-based copolymers having a broad molecular weight distribution and a broad comonomer distribution using a single tubular reactor. The process for producing propylene-based copolymers comprises introducing propylene and at least one other olefin comonomer into a tubular reactor to produce a broad comonomer distribution, an M of about 10 kg / mol to about 2,000 kg / mol. W and producing a propylene-based copolymer having an MWD of about 2.0 to about 10.0. The tubular reactor may include one or more heat exchanger elements, preferably a spiral wound heat exchanger. The propylene-based copolymer composition may include propylene-derived units and at least one other comonomer-derived units, and the copolymer composition may have a broad comonomer distribution, an MWD of 10 kg / mol to about 2,000 kg / mol. W and a MWD of from about 2.0 to about 10.0. The composition may have a broad orthogonal comonomer distribution.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 290,874, filed December 17, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0002] Field FIELD OF THE DISCLOSURE The present invention relates generally to processes for producing propylene-based copolymers and copolymer compositions produced thereby. More particularly, the embodiments relate to a process for producing propylene-based copolymers having broad comonomer distribution and broad molecular weight distribution using a tubular reactor. [Background technology]

[0003] background Propylene-based copolymers are in high demand due to their high flexibility, toughness, transparency, and processability. They have a wide range of applications, such as blue and cast films, injection molded containers and other articles, and nonwovens. Both high and low viscosity propylene-based elastomers are produced. One type of catalyst system that can be used to produce propylene-based copolymers is a metallocene-based catalyst system. Metallocene catalysts are homogeneous single-site catalysts that contain organometallic coordination compounds in which one or two cyclopentadienyl or substituted cyclopentadienyl rings are π-bonded to a central transition metal atom. Metallocene catalysts typically produce propylene-based copolymers with narrow molecular weight distributions and uniform comonomer distributions across a population of polymer chains. This is in contrast to broad molecular weight distributions and broad comonomer distributions (BCD), especially broad orthogonal comonomer distributions (BOCD).

[0004] Although polymers with narrow molecular weight distribution and uniform comonomer distribution may be advantageous for certain processes and end uses, this type of polymer may be undesirable for other uses. For example, narrow molecular weight distribution polymers may require the use of fluoropolymer additives to process the polymer at desired production rates without flow instabilities, such as melt fracture. Unfortunately, the use of fluoropolymer processing aids increases the cost of producing finished products from the polymer. Stability in other polymer processing operations, such as blown film and blow molding, is often reduced for narrow molecular weight distribution polymers compared to broader molecular weight distribution polymers, resulting in reduced production rates. Also, polymers with uniform comonomer distribution often have a poor balance of mechanical properties, such as strength, stiffness, tear resistance, and impact resistance, compared to polymers with non-uniform BCD. The polymers may also have problems with pellet stability, crosslinking effectiveness, and elastic recovery. Therefore, it is highly desirable to have the ability to control the molecular weight distribution and comonomer distribution of polymers produced using metallocene-based catalysts.

[0005] Other catalysts such as chromium or Ziegler-Natta (ZN) type catalysts can be used to produce propylene-based polymers with broader molecular weight distributions. However, when either chromium or ZN catalysts are utilized, the resulting comonomer distribution rarely, if at all, has BOCD. Also, the use of hydrogen in the polymerization process can cause the molecular weight distribution of the resulting polymer to be narrow. Thus, the use of such catalysts limits the ability to control the degree of molecular weight distribution of the resulting polymer. The use of ZN catalysts also has an undesirable tendency to produce polymers with many oligomers and low molecular weight ends that can be detrimental to the mechanical properties of the polymer. Also, peroxides are often required to decompose the polymer when its use in fiber and nonwoven applications is desired.

[0006] To overcome the challenges involved in using chromium or ZN catalysts, mixed metallocene catalyst systems have been developed that contain multiple metallocene catalysts that can be utilized to control the molecular weight distribution of the polymer. Methods have also been developed to control the molecular weight distribution using two or more continuous stirred tank reactors (CSTRs) with metallocene catalyst systems. These options do not provide effective control of the molecular weight distribution and the comonomer distribution simultaneously. One drawback of using multiple CSTRs is the expense required to build multiple reactors. Also, using multiple CSTRs does not achieve as wide a MWD as desired. The use of multiple CSTRs creates greater operational complexity than operating only one reactor. Additionally, two CSTRs may result in a bimodal distribution from the combination of two individual fractions rather than a continuous spectrum of comonomer content. Since the comonomer distribution from the individual CSTRs is most likely to be uniform, the multi-CSTR approach may result in a linear combination of uniform distributions that simulates a wide distribution. This is in contrast to a smooth continuous continuum across a wide distribution. The other option of using multiple types of catalysts may be more expensive and complicated than using a single type of catalyst. This option can entail the difficulty of having to identify and / or develop new catalytic molecules that are capable of being combined and, when combined, result in specific desired products. Therefore, there is a need for a method to produce propylene-based copolymers inexpensively using metallocene-based catalysts and solution polymerization processes. It would also be desirable to produce propylene-based copolymers with a good balance of properties to allow the copolymers to be used in a wide variety of applications. It would also be advantageous to have the ability to produce propylene-based copolymers with broad molecular weight distributions and comonomer distributions, especially when the comonomer distribution is BOCD. Summary of the Invention

[0007] summary A process for producing a propylene-based copolymer having a broad comonomer distribution and a broad molecular weight distribution using a tubular reactor is provided. In one or more embodiments, the process for producing a propylene-based copolymer comprises introducing propylene and at least one other olefin comonomer into a tubular reactor to produce a broad comonomer distribution M of about 10 kg / mol to about 2,000 kg / mol. W and producing a propylene-based copolymer having an MWD of about 2.0 to about 10.0. The tubular reactor may include a recirculation pump and / or one or more heat exchanger elements, preferably a spiral wound heat exchanger. In one or more embodiments, the propylene-based copolymer composition can include propylene-derived units and at least one other comonomer-derived units, and the copolymer composition has a broad comonomer distribution M of about 10 kg / mol to about 2,000 kg / mol. W and an MWD of from about 2.0 to about 10.0. The copolymer composition may also have a broad orthogonal comonomer distribution.

[0008] So that the above-mentioned features of the invention may be understood in detail, a more particular description of the invention briefly summarized above can be made with reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings merely illustrate typical embodiments of the invention and should not be considered as limiting the scope of the invention, since the invention may admit of other equally effective embodiments. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1a shows a tubular reactor containing a spiral heat exchanger arranged in a substantially vertical direction according to one or more embodiments provided herein, and FIG. 1b shows a plan view of the spiral heat exchanger of FIG. 1a. [Diagram 2] 1 shows a tubular reactor containing a spiral heat exchanger in a substantially horizontal orientation according to one or more embodiments provided herein. [Diagram 3]1 is a graph showing molecular weight distribution versus recycle rate of a propylene-ethylene copolymer produced according to one or more embodiments provided herein. [Figure 4] FIG. 4 is a graph showing ethylene content distribution across a logarithmic scale of molecular weight for the propylene-ethylene copolymers of FIG. [Diagram 5] 1 is a graph showing ethylene content distribution across a logarithmic scale of molecular weight for propylene-ethylene copolymers produced by a conventional process. [Figure 6] 1 is a graph showing molecular weight distribution and ethylene content distribution for lower viscosity propylene-ethylene copolymers produced in accordance with one or more embodiments provided herein. [Figure 7] 1 is a graph showing molecular weight distribution and ethylene content distribution for propylene-ethylene copolymers produced according to one or more embodiments provided herein. [Figure 8] FIG. 1 is a graph showing the monomer incorporation and breadth of monomer sequence length distribution as determined by Solvent Gradient Interactive Chromatography for propylene-ethylene copolymers produced according to one or more embodiments provided herein. [Figure 9] 1 is a graph showing molecular weight distribution and ethylene content distribution for propylene-ethylene copolymers produced with various recycle rates according to one or more embodiments provided herein. [Figure 10] 1 is a graph showing molecular weight distribution and ethylene content distribution for lower viscosity propylene-ethylene copolymers produced in accordance with one or more embodiments provided herein. [Figure 11] 1 is a graph showing molecular weight distribution and ethylene content distribution for propylene-ethylene copolymers produced according to one or more embodiments provided herein. [Figure 12]1 is a graph showing molecular weight distribution and ethylene content distribution for propylene-ethylene copolymers produced using a Ziegler-Natta catalyst. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Detailed Description It should be understood that the following disclosure describes several exemplary embodiments for implementing various features, structures, and / or functions of the present invention. The following describes exemplary embodiments of components, arrangements, and configurations to simplify the present disclosure. However, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the present invention. Furthermore, the present disclosure may repeat reference numbers and / or characters in various exemplary embodiments and throughout the figures provided herein. This repetition is for simplicity and clarity, and does not in itself dictate a relationship between the various exemplary embodiments and / or configurations discussed in the figures. Furthermore, the following exemplary embodiments may be used together in any combination manner. That is, any element of an exemplary embodiment may be used in any other exemplary embodiment without departing from the scope of the present disclosure. Additionally, certain terms are used throughout the following description and claims to refer to specific components. As will be apparent to one of ordinary skill in the art, various entities may refer to the same component by different names, and similarly, the naming conventions for the elements described herein are not intended to limit the scope of the invention unless specifically defined herein. Additionally, the naming conventions used herein are not intended to distinguish between components that differ in name but not function.

[0011] In the discussion below and in the claims, the terms "including" and "comprising" are used in an open-ended manner and should therefore be interpreted to mean "including, but not limited to." The phrase "consisting essentially of" means that the described and / or claimed composition does not contain any other components that would substantially alter its properties by more than 5%, and in any case does not contain any other components to a level of more than 3% by weight. The term "or" is intended to encompass both exclusive and inclusive cases, i.e., "A or B" is intended to be synonymous with "at least one of A and B," unless expressly specified otherwise in this specification. The indefinite articles "a" and "an" refer to both the singular (i.e., "one") and plural references (i.e., one or more), unless the context clearly dictates otherwise. For example, embodiments using "an olefin" include embodiments using one, two, or three or more olefins, unless specified to the contrary or the context clearly dictates that only one olefin is used. The term "wt%" means weight percentage, "vol%" means volume percentage, "mol%" means mole percentage, "ppm" means parts per million, and "ppm wt" and "wppm" are used interchangeably to mean parts per million by weight. All concentrations herein are expressed based on the total amount of the composition in question unless otherwise specified.

[0012] The term "polymer" refers to any two or more of the same or different repeating / mer units or units. The term "homopolymer" refers to a polymer having units that are the same. The term "copolymer" refers to a polymer having two or more units that are different from each other, including terpolymers and the like. The term "terpolymer" refers to a polymer having three units that are different from each other. The term "different" when it refers to units means that the units differ from each other by at least one atom or analogically. Similarly, the definition of polymer as used herein includes homopolymers, copolymers, and the like. By way of example, when a copolymer is said to have a "propylene" content of 10 wt% to 30 wt%, it is understood that the repeating / mer units or simply units in the copolymer are derived from propylene in the polymerization reaction, and the derived units are present at 10 wt% to 30 wt% based on the weight of the copolymer.

[0013] The term "continuous" refers to a system that operates without interruption or cessation. For example, a continuous process for producing a polymer would be one in which reactants are continuously introduced into one or more reactors and the polymer product is continuously withdrawn. The term "solution polymerization" refers to a polymerization process in which the polymer is dissolved in a liquid polymerization medium, such as an inert solvent, monomer(s), or a blend thereof. Solution polymerizations are typically homogeneous. The term "homogeneous polymerization" refers to a polymerization process in which the polymer product is dissolved in the polymerization medium. The system is preferably not turbid, as described in J. Vladimir Oliveira, C. Dariva, and JC Pinto, Ind. Eng. Chem. Res., 29, 2000, 4627. A homogeneous polymerization process is typically one in which at least 90 wt% of the product is dissolved in the reaction medium.

[0014] The term "laminar" flow refers to the flow of a fluid (e.g., gas, liquid) in parallel layers without disruption between the layers. Fluids may exhibit laminar flow near solid boundaries. "Near-laminar" flow refers to the flow of a fluid in parallel layers with minimal disruption between the layers. As used herein, "Mn" refers to the number average molecular weight of the various polymers in the polymeric material, "Mw" refers to the weight average molecular weight of the various polymers in the polymeric material, and "Mz" refers to the z-average molecular weight of the various polymers in the polymeric material. The terms "molecular weight distribution" (MWD) and "polydispersity index" (PDI) are used interchangeably to refer to the ratio of Mw to Mn. Also, the term "broad comonomer distribution" (BCD) refers to a non-uniform comonomer distribution, with a "uniform distribution" said to have all CD slope values ​​between -1 and 1. The term "broad orthogonal comonomer distribution" (BOCD) refers to a positively sloping comonomer distribution, where the comonomer content increases with increasing logarithm of the molecular weight of the polymer. A BOCD polymer has at least one CD slope of 1.5 or greater. The nomenclature of elements and their groups used herein follows the Periodic Table used by the International Union of Pure and Applied Chemistry since 1988. An example of a Periodic Table is shown on the inside front cover page of Advanced Inorganic Chemistry, 6th Edition by F. Albert Cotton et al. (John Wiley & Sons, Inc., 1999).

[0015] A detailed description is provided below. Each appended claim defines a separate invention, which is recognized for infringement purposes as including equivalents to the various elements or limitations specified in the claim. Depending on the context, all references to the "invention" may refer only to certain specific embodiments. In other cases, it will be recognized that references to the "invention" refer to one or more, but not necessarily all, of the subject matter recited in the claims. Each of the inventions is described in more detail below, including specific embodiments, variations, and examples, but the invention is not limited to these embodiments, variations, or examples, and these embodiments, variations, or examples are included to enable one of ordinary skill in the art to make and use the invention when the information in this disclosure is used in conjunction with publicly available information and technology.

[0016] Provided herein is a process for the manufacture of propylene-based copolymers that may include the step of introducing propylene and at least one other olefin comonomer into a single tubular reactor to produce both high and low viscosity propylene-based copolymers comprising propylene-derived units and at least one other comonomer-derived units. The term "tubular reactor" refers to a reactor into which a feed is continuously introduced (e.g., via an inlet) and from which a product is continuously removed (e.g., via an outlet), and in which there is typically no stirring. For example, the tubular reactor may be substantially tubular in shape and may include straight pipes or loops to allow for recirculation. The tubular reactor may include one or more plug flow components and / or one or more laminar flow elements. The tubular reactor may include a recirculation pump. Preferably, the tubular reactor may include one or more heat exchangers. The heat exchanger(s) may be a spiral wound heat exchanger (SHE). The polymerization process may include other polymerization reactors in addition to the tubular reactor. The polymerization reaction in the tubular reactor is preferably carried out with a single type of catalyst, i.e., a catalyst that is not mixed or blended with any other catalyst in the tubular reactor. This single type of catalyst can be a single-site catalyst, such as a metallocene catalyst, a half-metallocene catalyst, or a post-metallocene catalyst. Other reactors in the polymerization process can contain different types of catalysts.

[0017] Shifting from a conventional CSTR to a tubular reactor allows for the introduction of heterogeneity not only along the axis of the fluid flow direction but also radially across each tube in the reactor. Utilizing this heterogeneity through temperature and concentration gradients and controlling the degree of heterogeneity through recycle rate (RR) can greatly expand the product design space that can be reached with a single reactor and a single type of metallocene catalyst. Multi-reactor or multi-catalyst operation can also be utilized when a greater degree of structural complexity is desired in the final polymer product. Utilizing a tubular reactor with recycle can improve product design possibilities and product tunability for superior performance in the application of interest. The use of a tubular reactor also provides a smooth continuous comonomer content over a wide distribution.

[0018] Surprisingly, using the processes disclosed herein, it is possible to produce copolymers with broad comonomer distributions (BCD), M ranging from about 10 to about 2,000 kg / mol, even in the presence of hydrogen. Wand a broad MWD of about 2.0 to about 10.0 as measured by gel permeation chromatography (GPC). A polymer with a broad comonomer distribution can have either relatively high molecular weight chains with lower comonomer incorporation or relatively low molecular weight chains with higher comonomer incorporation. The comonomer composition disclosed herein can also have a broad orthogonal comonomer distribution (BOCD) with a comonomer distribution (CD) slope 20-80, preferably from about 1.5 to about 30.0. Details on how to determine the CD slope are provided in the Test Procedures below. As previously mentioned, olefin copolymers with these properties cannot usually be produced using only one metallocene-based catalyst and one CSTR. Thus, the process disclosed herein is not only simpler and more cost-effective than other processes, but also provides a high level of control of the MWD and comonomer distribution. Unexpectedly, it has also been found that the MWD of propylene-based copolymers can be increased by reducing the recycle rate of the SHE reactor(s). Additionally, the copolymer composition may have a propylene-based crystallinity with a heat of fusion that may range from as low as about 0.5, 5.0, or 10.0 J / g to as high as about 60.0, 70.0, or 75.0 J / g, as measured using differential scanning calorimetry (DSC). The copolymer composition may also exhibit a melt flow rate (MFR) according to ASTM D1238 (2.16 kg, 230° C.) of about 0.1 to about 1,000 g / 10 min, or a Brookfield viscosity (BV) according to ASTM D1238 (190° C.) of about 400 to 50,000 cP.

[0019] Propylene-based copolymer compositions may exhibit an improved balance of mechanical properties, such as strength, stiffness, tear resistance, and impact resistance. They may also have improved pellet stability, crosslinking effectiveness, and compatibility with other polymers, such as polypropylene (PP) homopolymer. As a result of the remarkable crosslinking effectiveness of the propylene-based copolymer compositions, these compositions can be used in applications such as solar cells as well as wire and cable. Due to their excellent balance of mechanical properties, the copolymer compositions can also be used in a wide variety of applications, such as elastic nonwovens (e.g., for sanitary purposes), elastic films and laminates, plastic piping (e.g., medical piping), and plastic bags (e.g., medical IV bags). Since the propylene-based copolymers disclosed herein are highly compatible with other polymers, they can be blended with other copolymers as well as homopolymers, such as PP homopolymer, to form polymer blend compositions.

[0020] Polymerization Process The polymerization process may be a solution polymerization process in which the monomer, comonomer, and catalyst system are contacted in a solution phase in which the polymer is formed. Preferably, the process conditions are sufficient to keep the polymer in the solution phase, which is preferably a single phase. A solvent may be present during the polymerization process. Solvents suitable for the polymerization process may include non-coordinating inert liquids. Examples include straight and branched chain hydrocarbons, such as isobutane, butane, pentane, isopentane, hexane, isohexane, heptane, octane, dodecane, and mixtures thereof; cyclic and alicyclic hydrocarbons, such as cyclohexane, cycloheptane, methylcyclohexane, methylcycloheptane, and mixtures thereof, such as Isopar™ commercially available from ExxonMobil; perhalogenated hydrocarbons, such as perfluorinated alkanes, and chlorobenzene; and aromatic and alkyl-substituted aromatic compounds, such as benzene, toluene, mesitylene, and xylene. In a preferred embodiment, the monomer and comonomer feed concentration for polymerization is 60 vol.% or less, preferably 40 vol.% or less, and more preferably 20 vol.% or less, based on the total volume of the feedstream.

[0021] Monomers and Comonomers As previously mentioned, the monomer may be propylene (C3). The at least one other olefin comonomer may be or include ethylene (C2), a substituted or unsubstituted C4-C40 olefin (preferably a C4-C20 olefin), or a combination thereof, with C2 being most preferred. The C4-C40 olefin comonomer may be linear, branched, or cyclic. Suitable C4-C40 cyclic olefins may be strained or unstrained monocyclic or polycyclic, and may optionally contain heteroatoms and / or one or more functional groups. The C3 concentration in the reactor may range from 0.1 to 30.0 wt%, and the comonomer concentration in the reactor may range from 0.1 to 30.0 wt%.

[0022] Specific examples of suitable C4-C20 comonomers include butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, norbornene, norbornadiene, dicyclopentadiene, cyclopentene, cycloheptene, cyclooctene, cyclooctadiene, cyclododecene, 7-oxanorbornene, 7-oxanorbornadiene, substituted derivatives thereof, and isomers thereof, preferably hexene, heptene, octene, nonene, decene, dodecene, cyclooctene, 1,5-cyclooctadiene, 1-hydroxy-4-cyclooctene, 1-acetoxy-4-cyclooctene, 5-methylcyclopentene, cyclopentene, dicyclopentadiene, norbornene, norbornadiene, and their respective homologs and derivatives, preferably norbornene, norbornadiene, and dicyclopentadiene.

[0023] In preferred embodiments, one or more dienes (diolefin monomers) are added to the polymerization process. The diene may be present in the polymer produced herein at up to 10 wt%, preferably 0.00001-8.0 wt%, preferably 0.002-8.0 wt%, more preferably 0.003-8.0 wt%, based on the total weight of the composition. In some embodiments, 500 ppm or less, preferably 400 ppm or less, preferably 300 ppm or less of diene is added to the polymerization. In other embodiments, at least 50 ppm, or 100 ppm or more, or 150 ppm or more of diene is added to the polymerization. Suitable diolefin monomers include any hydrocarbon structure having at least two unsaturated bonds, preferably C4-C30, where at least one of the unsaturated bonds is easily incorporated into the polymer during chain growth. More preferably, the diolefin monomer is selected from α,ω-diene monomers (i.e., divinylic monomers). More preferably, the diolefin monomer is a linear divinylic monomer, most preferably a linear divinylic monomer containing from 4 to 30 carbon atoms. Specific examples of preferred dienes include butadiene, pentadiene, hexadiene, heptadiene, octadiene, nonadiene, decadiene, undecadiene, dodecadiene, tridecadiene, tetradecadiene, pentadecadiene, hexadecadiene, heptadecadiene, octadecadiene, nonadecadiene, icosadiene, heneicosadiene, docosadiene, tricosadiene, tetracosadiene, pentacosadiene, helicosadiene, hexadiene ... Particularly preferred dienes include 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene, 1,13-tetradecadiene, and low molecular weight polybutadienes (Mw less than 1000 g / mol). Preferred cyclic dienes include cyclopentadiene, 5-vinyl-2-norbornene, norbornadiene, 5-ethylidene-2-norbornene, divinylbenzene, and dicyclopentadiene or higher ring-containing diolefins with or without substitution at the various ring positions.

[0024] Catalyst Systems The catalyst system used in the polymerization process described herein may include a bulky ligand transition metal catalyst known as a "metallocene catalyst" or a "metallocene catalyst precursor". The bulky ligand may contain a multiplicity of bonded atoms, preferably carbon atoms, forming a group that may be cyclic with one or more optional heteroatoms. The bulky ligand may be a metallocene-type cyclopentadienyl derivative that may be mononuclear or polynuclear. One or more bulky ligands may be bonded to the transition metal atom. The bulky ligand is presumed, according to prevailing scientific theories, to remain in place during the polymerization to provide a homogeneous polymerization effect. Other ligands may be bonded or coordinated to the transition metal, preferably releasably by a cocatalyst or activator, such as a hydrocarbyl or halogen leaving group. The desorption of any such ligand is presumed to result in the creation of a coordination site at which an olefin monomer may be inserted into the polymer chain. The transition metal atom may be a Group IV, V or VI transition metal of the Periodic Table of Elements. The transition metal atom is preferably a Group IVB atom.

[0025] Metallocene catalyst precursors generally require activation with a suitable cocatalyst (sometimes called an activator) to produce an active metallocene catalyst, i.e., an organometallic complex that has vacant coordination sites capable of coordinating, inserting, and polymerizing olefins. The term "catalyst system" refers to a catalyst precursor / activator pair. When "catalyst system" is used to describe the pair before activation, it refers to the unactivated catalyst (pre-catalyst) along with an activator and, optionally, a co-activator. When "catalyst system" is used to describe the pair after activation, it refers to the activated catalyst and an activator or other charge-balancing component. The transition metal compound may be neutral, as in a pre-catalyst, or may be a charged species with a counterion, as in an activated catalyst system. The term "catalyst system" may also include multiple catalyst precursors and / or multiple activators and, optionally, a co-activator. Catalyst precursors are often also called precatalysts, catalyst compounds, transition (or lanthanide or actinide) metal compounds, or transition (or lanthanide or actinide) metal complexes. These terms are used interchangeably. Activators and cocatalysts (or cocatalysts) are also used interchangeably. Scavengers are compounds that promote polymerization, typically by removing impurities. Scavengers may also act as activators and are sometimes called coactivators. A coactivator that is not a scavenger may be used in combination with an activator to form an active catalyst. In some embodiments, the coactivator may be premixed with the transition metal compound to form an alkylated transition metal compound.

[0026] An activator or cocatalyst is a compound or mixture of compounds capable of activating a precatalyst to form an activated catalyst. The activator can be a neutral compound (also called a neutral activator), such as trisfluorophenyl boron or trisperfluorophenyl aluminum, or an ionic compound (also called a separate ionic activator), such as dimethylanilinium tetrakis-perfluorophenyl borate or triphenyl carbonium tetrakis-perfluoro naphthyl borate. These types of activators are also commonly called non-coordinating anion activators (NCA activators) due to the common belief held by those skilled in the art that the reaction of the activator with the precatalyst forms a cationic metal complex and an anion non-coordinating or weakly coordinating anion (NCA). These types of activators, which are separate characteristic compounds by definition, exclude alumoxane cocatalysts, which are mixtures. The use of the term NCA is utilized as an adjective to describe the type of activator, as in NCA activators, or as a noun to describe the non-coordinating or weakly coordinating anion derived from the NCA activator.

[0027] The process described herein may use any catalyst system capable of polymerizing the monomers disclosed herein, provided that the catalyst system is sufficiently active under the polymerization conditions disclosed herein. Thus, Group 3-10 transition metal compounds or lanthanide or actinide metal compounds may form suitable catalysts. Suitable olefin polymerization catalysts should be capable of coordinating or otherwise combining with the alkenyl unsaturation. Exemplary catalysts include, but are not limited to, metallocene catalyst compounds. Preferably, the catalyst is used in the cationic state and is stabilized by a cocatalyst or activator. Typically, during polymerization, d 0 Group 4 metallocenes (i.e., titanium, hafnium, or zirconium) that exist in a monovalent cationic state and have one or two ancillary ligands are particularly preferred. An important feature of the catalyst for coordination polymerization is that the precatalyst contains an abstractable ligand and another ligand into which ethylene (or other olefin) can be inserted.

[0028] Representative metallocene-type compounds useful herein are represented by the formula: T j L A L B L C i MDE where M is a Group 3, 4, 5, or 6 transition metal atom, or a Lanthanide metal atom, or an Actinide metal atom, preferably a Group 4 transition metal atom selected from titanium, zirconium, or hafnium; L A i.e., the ancillary ligand is a substituted or unsubstituted monocyclic or polycyclic arenyl that is π-bonded to M; B , L A or J, a heteroatom ancillary ligand bonded to M through a heteroatom; L A Ligand and L BThe ligands may be covalently bridged together through a bridging group T containing a Group 14, 15, or 16 element or boron, where j is 1 when T is present and j is 0 when T is absent (j is equal to 0 or 1); L C i is an optional neutral non-oxidizing ligand having a coordinate bond to M (i is equal to 0, 1, 2, or 3); and D and E are independently monoanionic labile ligands, each having a σ bond to M, and optionally each other or L A , L B Or L C is cross-linked to.

[0029] As used herein, the term "monocyclic arenyl ligand" is used herein to refer to a substituted or unsubstituted monoanionic C5-C6 ligand containing an aromatic five-membered hydrocarbyl single ring structure (also referred to as a cyclopentadienyl ring). 100 It means a hydrocarbyl ligand. As used herein, the term "polycyclic arenyl ligand" is used herein to refer to a substituted or unsubstituted monoanionic C8-C12 ligand containing one or two partially unsaturated, or aromatic, hydrocarbyl or heteroatom-substituted hydrocarbyl ring structures (which may be fused to further saturated, partially unsaturated, or aromatic hydrocarbyl or heteroatom-substituted hydrocarbyl rings). 103 It means a hydrocarbyl ligand. Cyclopentadienyl, indenyl, fluorenyl, tetrahydroindenyl, cyclopenta[b]thienyl, and cyclopenta[b]pyridyl ligands are all examples of arenyl ligands.

[0030] L ANon-limiting examples of the ligands include substituted or unsubstituted cyclopentadienyl ligands, indenyl ligands, fluorenyl ligands, dibenzo[b,h]fluorenyl ligands, benzo[b]fluorenyl ligands, azulenyl ligands, pentalenyl ligands, cyclopenta[b]naphthyl ligands, cyclopenta[a]naphthyl ligands, cyclopenta[b]thienyl ligands, cyclopenta[c]thienyl ligands, cyclopenta[b]pyrrolyl ligands, cyclopenta[c]pyrrolyl ligands, cyclopenta[b] furyl ligands, cyclopenta[c]furyl ligands, cyclopenta[b]phosphoryl ligands, cyclopenta[c]phosphoryl ligands, cyclopenta[b]pyridyl ligands, cyclopenta[c]pyridyl ligands, cyclopenta[c]phosphinyl ligands, cyclopenta[b]phosphinyl ligands, cyclopenta[g]quinolyl, cyclopenta[g]isoquinolyl, indeno[1,2-c]pyridyl, and the like, including hydrogenated versions thereof, such as tetrahydroindenyl ligands.

[0031] L B Non-limiting examples of A In addition, the following are listed: B is defined as J, where J is of the formula J'-R" k-1-j where J' is bonded to M. J' is a heteroatom having a coordination number of 3 from Group 15 of the Periodic Table or a heteroatom having a coordination number of 2 from Group 16 of the Periodic Table, preferably nitrogen; R" is a C-C 100 substituted or unsubstituted hydrocarbyl groups; k is the coordination number of the heteroatom J', and "k-1-j" indicates the number of R" substituents attached to J'. Non-limiting examples of J include all isomers (including cyclics) of propylamido, butylamido, pentylamido, hexylamido, heptylamido, octylamido, nonylamido, decylamido, undecylamido, docecylamido, phenylamido, tolylamido, xylylamido, benzylamido, biphenylamido, oxo, sulfanediyl, hexylphosphido, and the like.

[0032] When present, T is a bridging group containing boron or an element of Group 14, 15 or 16. Examples of suitable bridging groups include R'2C, R'2Si, R'2Ge, R'2CCR'2, R'2CCR'2CR'2, R'2CCR'2CR'2CR'2, R'C=CR', R'2CSiR'2, R'2SiSiR'2, R'2CSiR'2CR'2, R'2SiCR'2SiR'2, R'2CGeR'2, R'2GeGeR'2, R R'2CGeR'2CR'2, R'2GeCR'2GeR'2, R'2SiGeR'2, R'B, R'2C-BR', R'2C-BR'-CR'2, R'2C-O-CR'2, R'2C-S-CR'2, R'2C-Se-CR'2, R'2C-NR'-CR'2, and R'2C-PR'-CR'2, where R' is hydrogen or C1-C 20 R' is a hydrocarbyl or substituted hydrocarbyl, optionally where two or more adjacent R' may join to form a substituted or unsubstituted, saturated, partially unsaturated or aromatic, cyclic or polycyclic substituent. Non-limiting examples of bridging groups, T, include CH2, CH2CH2, CMe2, SiMe2, SiEt2, SiPh2, SiMePh, Si(CH2)3, Si(CH2)4, Si(CH2)5, Si(Ph-p-SiEt3)2, and the like. Non-limiting examples of D and E are independently fluoro, chloro, bromo, iodo, methyl, ethyl, benzyl, dimethylamido, methoxy, and the like.

[0033] Suitable catalysts and catalyst systems that can be used herein include, but are not limited to, those described in US10,829,569; WO2020 / 167819; WO2020 / 167824; WO2020 / 167838; US2020 / 0255553; WO00 / 24793; and WO2021 / 162745A1, each of which is incorporated by reference in its entirety.

[0034] Preferred metallocene catalysts or metallocene catalyst precursors are cyclopentadienyl complexes having two Cp ring systems as ligands. The Cp ligands preferably form bent sandwich complexes with the metal and are preferably locked into a rigid configuration by bridging groups. These cyclopentadienyl complexes have the formula: (Cp 1 R 1 m )R 3 n (Cp 2 R 2 p )MX q In the formula, Cp 1 and Cp 2 are preferably identical; R 1 and R 2 are each independently a halogen or a hydrocarbyl, halocarbyl, hydrocarbyl-substituted organometallic or halocarbyl-substituted organometallic group containing up to 20 carbon atoms; m is preferably 1 to 5; p is preferably 1 to 5; and preferably two R 1 and / or R 2 Two R's on adjacent carbon atoms of the cyclopentadiene ring to which the substituent is attached 1 and / or R 2 The substituents combine to form a ring containing 4 to 20 carbon atoms; R 3 is a bridging group; n is the number of atoms in the direct chain between two ligands, preferably 1 to 8, most preferably 1 to 3; M is a transition metal having a valence of 3 to 6, preferably from Group 4, 5, or 6 of the Periodic Table of the Elements, preferably in its highest oxidation state; each X is a non-cyclopentadienyl ligand and is independently a hydrocarbyl, oxyhydrocarbyl, halocarbyl, hydrocarbyl-substituted organometallic, oxyhydrocarbyl-substituted organometallic or halocarbyl-substituted organometallic group containing up to 20 carbon atoms; q is equal to the valence of M minus 2. In a preferred embodiment, M is a Group 4 metal, preferably Hf or Zr. In another preferred embodiment, (Cp 1 R 1 m ) and (Cp 2 R2 p ) are each independently a substituted or unsubstituted indenyl group.

[0035] As already mentioned, metallocene catalysts or metallocene catalyst precursors can be activated with non-coordinating anions. The term "non-coordinating anions" refers to anions that do not coordinate to transition metal cations or coordinate only weakly to cations, and therefore remain unstable enough to be displaced by neutral Lewis bases. A "compatible" non-coordinating anion is an anion that does not decompose to neutrality when the initially formed complex decomposes. Furthermore, this anion typically does not transfer anionic substituents or fragments to the cation to form neutral 4-coordinate metallocene compounds and neutral by-products from the anion. A suitable non-coordinating anion is an anion that is compatible and stabilizes the metallocene cation in the sense of balancing its ionic charge, and yet retains sufficient lability to allow displacement by ethylenically or acetylenically unsaturated monomers during polymerization. Furthermore, suitable anions may be large or bulky in the sense of molecular size sufficient to significantly inhibit or prevent neutralization of the metallocene cation by Lewis bases other than the polymerizable monomer that may be present in the polymerization process. Typically, the anion will have a molecular size of 4 Å or greater. For a detailed description of suitable metallocene catalyst systems, see US Pat. No. 8,263,707, which is incorporated herein by reference.

[0036] Tubular Reactor System The tubular reactor system may include a form of heat removal. This heat removal may be accomplished by cooling the feed before it enters the reactor. Heat removal may also be accomplished by including a heat exchanger in the tubular reactor. In a preferred embodiment, the heat exchanger is or may include a spiral wound heat exchanger. Turning to the drawings, FIG. 1a shows a suitable tubular reactor with a spiral heat exchanger. As shown, a stream 1 containing monomer, comonomer, and catalyst system can enter the tubular reactor 2 and travel through a spiral heat exchanger 3. A stream 4 containing the copolymer product, unreacted monomer and / or comonomer, and quenched or unquenched catalyst system can exit the reactor 2. A stream 5 containing a heat exchange medium can flow through the spiral heat exchanger 3. The at least one spiral heat exchanger can include a body formed by at least one spiral sheet wound to form a spiral arranged radially around the axis of the spiral heat exchanger. The spiral can form at least one flow path for the flow of the heat exchange medium, and the spiral can be substantially enclosed by a cylindrical shell, as shown in FIG. 2. The cylindrical shell can also include at least one inlet and at least one outlet in fluid communication with at least one flow path for supplying and removing the heat exchange medium.

[0037] The at least one spiral heat exchanger may be oriented such that the monomer, comonomer, catalyst system, and copolymer product flow axially through the flow passages formed between the spirals 6 of the at least one spiral heat exchanger, as shown in FIG. 1b, thereby allowing the feed and polymer product to flow as they move through the at least one spiral heat exchanger. In other words, the monomer, comonomer, catalyst system, and copolymer product may flow through the at least one spiral heat exchanger in a cross-flow direction relative to the spirals of the at least one spiral heat exchanger. As used herein, a "cross-flow" direction refers to a flow that is substantially orthogonal to the spirals of the at least one spiral heat exchanger. Substantially orthogonal may include the monomer, comonomer, catalyst system, and copolymer product flow at an angle of 70° to 110°, preferably 80° to 100°, more preferably 85° to 95°, more preferably 88° to 92°, and most preferably 90°, relative to the spirals of the at least one spiral heat exchanger.

[0038] As shown in FIG. 1a, the at least one spiral heat exchanger can be arranged in a substantially vertical direction such that the monomer, comonomer, catalyst system, and copolymer product flow through the at least one spiral heat exchanger in a substantially vertical direction. The geometrical arrangement of the at least one spiral heat exchanger is not limited to the vertical arrangement, but can be arranged in any direction, so long as the feed and product flow through the at least one spiral heat exchanger in a cross-flow direction relative to the spirals of the at least one spiral heat exchanger. For example, the at least one spiral heat exchanger can be arranged in a substantially horizontal direction such that the monomer, comonomer, catalyst system, and copolymer product flow through the at least one spiral heat exchanger in a substantially horizontal direction, as shown in FIG. 2.

[0039] Alternatively, the at least one spiral heat exchanger can include a plurality, e.g., at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15, at least 16, at least 17, at least 18, at least 19, at least 20, at least 21, at least 22, at least 23, at least 24, etc., spiral heat exchangers. The at least one spiral heat exchanger used in the process described herein may be any suitable spiral heat exchanger known in the art.Non-limiting examples of suitable spiral heat exchangers include those described in U.S. Patent Nos. 8,622,030; 8,075,845; 8,573,290; 7,640,972; 6,874,571; 6,644,391; 6,585,034; and 4,679,621; U.S. Publication Nos. 2010 / 0170665; 2010 / 0008833; 2002 / 0092646; and 2004 / 0244968, and International Publication No. WO / 2017 / 058385, the contents of each of which are incorporated herein by reference. Additionally or alternatively, the at least one spiral heat exchanger has a diameter of about 66 to about 98 m 2 / m 3 (20 to 30 ft2 / ft3). Advantageously, the spiral heat exchanger may have an open circuit height of 0.15 to 9.1 m (0.5 to 30 ft), preferably 0.3 to 7.6 m (1 to 25 ft), 0.9 to 6.1 m (3 to 20 ft), 1.5 to 4.6 m (5 to 15 ft), or 1.5 to 3 m (5 to 10 ft).

[0040] The heat exchange medium flowing through the spirals of the at least one spiral heat exchanger may be any suitable heat exchange medium known in the art. Particularly useful heat exchange media include media that are stable at the reaction temperature, typically at 200° C. or higher. Examples of heat transfer media include water and other aqueous solutions, oils (e.g., hydrocarbons such as mineral oil, kerosene, hexane, pentane, etc.), and synthetic media, such as those commercially available under the trade name DOWTHERM™ from The Dow Chemical Company (Midland, Michigan), e.g., grades A, G, J, MX, Q, RP, and T. When water is used, it is preferred that the water is under an appropriate amount of pressure so that it does not boil. Preferably, the heat exchange medium flows through the spirals at a temperature below the temperature of the feed stream. Additionally or alternatively, the heat exchange medium may flow through the spirals at a temperature above the precipitation point of the polymer. For example, the heat exchange medium may flow through the spiral at a temperature of 100°C to 150°C, preferably 120°C to 140°C, and more preferably 130°C.

[0041] In various embodiments, the at least one spiral heat exchanger is configured to provide a heat exchanger having a heat capacity of > about 100 Btu / hr-cubic feet-°F (about 1,860 W / cubic meters-°C), > about 150 Btu / hr-cubic feet-°F (about 2,795 W / cubic meters-°C), > about 200 Btu / hr-cubic feet-°F (about 3,725 W / cubic meters-°C), > about 250 Btu / hr-cubic feet-°F (about 4,000 W / cubic meters-°C), > about 300 Btu / hr-cubic feet-°F (about 5,000 W / cubic meters-°C), > about 400 Btu / hr-cubic feet-°F (about 6,000 W / cubic meters-°C), > about 500 Btu / hr-cubic feet-°F (about 7,000 W / cubic meters-°C), > about 600 Btu / hr-cubic feet-°F (about 8,000 W / cubic meters-°C), > about 700 Btu / hr-cubic feet-°F (about 9,000 W / cubic meters-°C), > about 800 Btu / hr-cubic feet-°F (about 10,000 W / cubic meters-°C), > about 900 Btu / hr-cubic feet-°F (about 11,000 W / cubic meters-°C), > about 1000 Btu / hr-cubic feet-°F (about 12,000 W / cubic meters-°C), > about 1500 Btu / hr-cubic feet-°F (about 16,000 W / cubic meters-°C), > about 1600 Btu / hr-cubic feet-°F (about 17,000 W / cubic meters-°C), > about >300 Btu / hour-cubic foot-°F (approx. 5,590 W / cubic meter-°C), >350 Btu / hour-cubic foot-°F (approx. 6,520 W / cubic meter-°C), >400 Btu / hour-cubic foot-°F (approx. 7,450 W / cubic meter-°C), >450 Btu / hour-cubic foot-°F (approx. 8 ,385W / cubic meter-℃), >approx. 500 Btu / hour-cubic foot-°F (approx. 9,315W / cubic meter-℃), >approx. 550 Btu / hour-cubic foot-°F (approx. 10,245W / cubic meter-℃), >approx. 600 Btu / hour-cubic foot-°F (approx. 11,180W / cubic meter-℃), >approx. 650 Btu / hour-cubic foot-°F (approx. 12,110 The at least one spiral heat exchanger can remove heat (e.g., generated during the polymerization reaction) at a rate of > about 700 Btu / hr-ft-°F (about 13,040 W / m-°C), > about 750 Btu / hr-ft-°F (about 13,970 W / m-°C), or > about 800 Btu / hr-ft-°F (about 14,905 W / m-°C). Preferably, the at least one spiral heat exchanger can remove heat at a rate of > about 400 Btu / hr-ft-°F (about 7,450 W / m-°C). Expressly disclosed ranges include any combination of the above recited values, for example, from about 100 to about 800 Btu / hour-cubic feet-°F (about 1,860 to about 14,905 W / cubic meters-°C), from about 200 to about 650 Btu / hour-cubic feet-°F (about 3,725 to about 12,110 W / cubic meters-°C), from about 350 to about 550 Btu / hour-cubic feet-°F (about 6,520 to about 10,245 W / cubic meters-°C).Preferably, the at least one spiral heat exchanger removes heat at a rate of from about 100 to about 800 Btu / hr-cubic feet-°F (about 1,860 to about 14,905 W / cubic meter-°C), more preferably from about 200 to about 700 Btu / hr-cubic feet-°F (about 3,725 to about 13,040 W / cubic meter-°C), and more preferably from about 300 to about 500 Btu / hr-cubic feet-°F (about 5,590 to about 9,315 W / cubic meter-°C).

[0042] Additionally, the use of at least one spiral heat exchanger in the polymerization processes described herein advantageously results in low pressure drop, leading to higher recycle and production rates. For example, the pressure drop across the at least one spiral heat exchanger may be < about 6.9 hPa (0.1 psi), < about 14 hPa (0.2 psi), < about 21 hPa (0.3 psi), < about 28 hPa (0.4 psi), < about 34 hPa (0.5 psi), < about 41 hPa (0.6 psi), < about 48 hPa (0.7 psi), < about 55 hPa (0.8 psi), < about 62 hPa (0.9 psi), < about 69 hPa (1.0 psi), < about 138 hPa (2.0 psi), < about 207 hPa (3.0 psi), < about 300 hPa (4.0 psi), < about 350 hPa (5.0 psi), < about 300 hPa (6.0 psi), < about 350 hPa (7.0 psi), < about 300 hPa (8.0 psi), < about 350 hPa (9.0 psi), < about 300 hPa (10.0 psi), < about 300 hPa (11.0 psi), < about 300 hPa (12.0 psi), < about 300 hPa (13.0 psi), < about 300 hPa (14.0 psi), < about 300 hPa (15.0 psi), < about 300 hPa (16.0 psi), < about 300 hPa (17.0 psi), < about 300 hPa (18.0 psi), < about 300 hPa (19.0 psi), < about 400 hPa (20.0 psi), < about 400 hPa (21.0 psi), < about 400 si), < about 276 hPa (4.0 psi), < about 345 hPa (5.0 psi), < about 414 hPa (6.0 psi), < about 483 hPa (7.0 psi), < about 552 hPa (8.0 psi), < about 621 hPa (9.0 psi), < about 689 hPa (10.0 psi), < about 827 hPa (12.0 psi), < about 965 hPa (14.0 psi), < about 1103 hPa (16.0 psi), < about 1241 hPa (18.0 psi), or < about 1379 hPa (20.0 psi). The pressure drop across the at least one spiral heat exchanger may be < about 689 hPa (10.0 psi), preferably < about 345 hPa (5.0 psi), more preferably < about 69 hPa (1.0 psi). Expressly disclosed ranges include any combination of the above recited values, such as, for example, from about 0.1 psi to about 20.0 psi, from about 0.5 psi to about 16.0 psi, from about 1.0 psi to about 12.0 psi, from about 3.0 psi to about 8.0 psi, etc. Preferably, the pressure drop across at least one spiral heat exchanger is from about 0.1 psi to about 14.0 psi, more preferably from about 0.5 psi to about 10.0 psi, and even more preferably from about 0.8 psi to about 2.0 psi, or from 0.2 psi to 0.8 psi per stage.

[0043] In various embodiments, the monomer, comonomer, catalyst system, and polymer may be maintained as substantially a single liquid phase under polymerization conditions. Although the flow of liquid through the at least one spiral heat exchanger may be plug flow in form, the flow is preferably laminar or near laminar. Preferably, the Reynolds number of the liquid flow can be >about 0.1, >about 1.0, >about 10.0, >about 20.0, >about 30.0, >about 40.0, >about 50.0, >about 60.0, >about 70.0, >about 80.0, >about 90.0, >about 100, >about 200, >about 300, >about 400, >about 500, >about 600, >about 700, >about 800, >about 900, >about 1,000, >about 1,100, >about 1,200, >about 1,300, >about 1,400, >about 1,500, >about 1,600, >about 1,700, >about 1,800, >about 1,900, >about 2,000, >about 2,100, or about 2,200. Additionally or alternatively, the Reynolds number of the liquid stream can be < about 40.0, < about 50.0, ≦ about 60.0, ≦ about 70.0, ≦ about 80.0, ≦ about 90.0, ≦ about 100, ≦ about 200, < about 300, ≦ about 400, ≦ ≦ 500, ≦ about 600, ≦ about 700, ≦ about 800, ≦ about 900, ≦ about 1,000, ≦ about 1,100, ≦ about 1,200, ≦ about 1,300, ≦ about 1,400, ≦ about 1,500, ≦ about 1,600, ≦ about 1,700, ≦ about 1,800, ≦ about 1,900, ≦ about 2,000, ≦ about 2,100 or < about 2,200. Explicitly disclosed ranges include any combination of the above recited values, such as about 0.1 to about 2,200, about 1.0 to about 1,400, about 1.0 to about 100, about 50.0 to about 900, etc. Preferably, the Reynolds number of the liquid is about 0.1 to about 2,200, preferably about 1.0 to about 1,000, preferably about 1.0 to about 100, more preferably about 1.0 to about 50. The Reynolds number is calculated using the hydraulic diameter (Dh), which is defined as Dh=4A / P, where A is the cross-sectional area of ​​the cross section of the flow path of the spiral heat exchanger, and P is the wetted perimeter. Zero shear viscosity is used to calculate the Reynolds number when using non-Newtonian fluids.

[0044] In various embodiments, the polymerization process can be carried out at a temperature of about 50° C. to about 220° C., preferably about 70° C. to about 210° C., preferably about 90° C. to about 200° C., preferably about 100° C. to about 190° C., preferably about 130° C. to about 160° C. The polymerization process can be carried out at a pressure of about 120 to about 1,800 psi (827.371 to 12,410.560 kPa), preferably about 200 to about 1,000 psi (1,378.950 to 6,894.760 kPa), preferably about 300 to about 800 psi (2,068.430 to 5,515.810 kPa). In various embodiments, the residence time in at least one spiral heat exchanger can be up to 24 hours or more, typically from about 1 minute to about 15 hours. The residence time is preferably from about 2 minutes to about 1 hour, from about 3 to about 30 minutes, from about 5 to about 25 minutes, or from about 5 to about 20 minutes. In various embodiments, hydrogen may be present during the polymerization process at a partial pressure of about 0.001 to about 50,000 psig (0.007 to 344.738 kPa), preferably about 0.010 to about 25,000 psig (0.069 to 172.369 kPa), and more preferably about 0.100 to about 10,000 psig (0.689 to 482.633 kPa). Alternatively, the hydrogen concentration in the feed may be 500 wppm or less, preferably 200 wppm or less. In various embodiments, the cement concentration of the resulting polymer can range from about 2 wt% to about 40 wt%, preferably from about 5 wt% to about 30 wt%, and more preferably from about 6 wt% to about 25 wt%. "Cement concentration" is defined herein as the mass of the resulting polymer based on total solvent (e.g., monomer, comonomer, and / or solvent).

[0045] The polymerization process may further include recycling at least a portion of the solvent, monomer / comonomer, catalyst system, and polymer exiting at least one reactor back through the reactor. In various embodiments, the propylene-based copolymers may be produced at a recycle ratio of about 0.1 to about 50.0, preferably about 3.0 to about 30.0, and more preferably about 3.0 to about 15.0. As used herein, "recycle ratio" is defined as the ratio of the flow rate of the recycle loop just before entering the spiral heat exchanger (single or series) divided by the flow rate of the unused feed to the spiral heat exchanger (single or series).

[0046] The recycle rate may be used to achieve a broad composition distribution. In one embodiment, the recycle rate remains constant during the reaction, but the monomer conversion varies across different zones along the axial length of each tubular reactor as the propylene-based copolymer is produced. Lower recycle rates result in greater variation in monomer conversion due to less mixing, flow, and solution uniformity, while higher recycle rates generally result in more uniform conversion due to more mixing and solution uniformity, all other factors being equal. While traditional CSTR processes are limited to certain variables, such as temperature or pressure, to control conversion, the tubular reactor provides an additional method of controlling conversion through the recycle rate. That is, the recycle rate may vary from polymerization reaction to polymerization reaction in a tubular reactor, but not in a CSTR. Conversion for a tubular reactor may range from about 30% to about 90%, preferably from about 30% to about 60%, and more preferably from about 45% to about 55%. A greater variation in conversion results in a polymer product with a broader compositional distribution, whereas a smaller variation in conversion results in a polymer product with a narrower compositional distribution. In various embodiments, different zones can be arranged along the tubular reactor and they can be isothermal or adiabatic. Preferably, about 60% of the copolymer is produced isothermally and about 40% of the copolymer is produced adiabatically. EXAMPLES

[0047] Working Example: The foregoing considerations can be further described with reference to the following non-limiting examples. Example 1 Four samples of high-viscosity copolymers of C3 and C2 (C3 / C2 copolymers) were prepared as follows using a SHE reactor (hereinafter referred to as "Tranter SHE reactor") commercially available from Tranter (registered trademark) and a single metallocene catalyst system at different recycle rates. C3 monomer, C2 comonomer, a metallocene (MCN) catalyst, namely dimethylsilylbis(indenyl)hafnium dimethyl, and a catalyst activator, namely dimethylanilinium tetrakis(heptafluoronaphthyl)borate, were added to the reactor to initiate liquid-phase polymerization. The first, second, and third C3 / C2 copolymer samples were produced at recycle rates (RR) of 24, 9, and 7, respectively (Comparative Example 2, Example 1a, and 1b). The fourth C3 / C2 copolymer sample was produced under the condition that the heat removal in the reactor (QR) was greater than the heat removed by cooling the feed (QF), expressed as QF < QR. This sample was also produced using an RR of 7 (Example 1c). The process conditions used for Ex. 1a - 1c are shown in Table 1 below. For comparison purposes, a sample of Vistamaxx (trademark) 6200 (Comparative Example 1), a high-viscosity C3 / C2 copolymer manufactured by ExxonMobil using an MCN catalyst and a CSTR, was obtained.

[0048] Table 1: Process Conditions for Ex. 1a - 1c [Table 1]

[0049] As shown in Figure 3, the MWD or PDI (Mw / Mn) of all the C3 / C2 copolymer samples (Ex.1a-1c and C.Ex.1-2) was measured and plotted as a function of recycle rate. Ideally, a CSTR will have well mixed reactor fluids, but the SHE reactor allows for a range of mixing degrees. An RR of about 30 approaches the well mixed condition characteristic of a CSTR for the three types of materials. Reducing the RR surprisingly resulted in an increase in the PDI and broadening of the MWD of the inventive copolymer samples Ex.1a-1c. This broadening of the MWD is believed to have occurred because, as the RR is reduced, the amount of material flowing back into the SHE reactor is reduced, which in turn reduces the degree of mixing in the reactor. As demonstrated in Figure 3, at an RR of 24, the PDI of C.Ex.2 is much closer to that of C.Ex.1, suggesting that the SHE reactor contains and extends the capabilities of the CSTR.

[0050] As shown in Figure 4, the C2 comonomer content was plotted as a function of molecular weight (M) on a logarithmic scale for each sample to show the CD of each sample. As shown, lowering the RR increased the slope of the CD. This suggests that a wide variety of polymer chains with different amounts of C2 incorporated were produced in the same reaction. Sample C.Ex.1 made using the CSTR reactor had the lowest PDI of 2.2 or the narrowest MWD and the most uniform CD with almost no slope compared to all other samples (Ex.1a-1c) made in the SHE reactor. Thus, the RR of the SHE reactor serves as a parameter by which in-reactor mixing can be adjusted despite utilizing the same catalyst and reaction scheme. Thus, process control as simple as single reactor operation, rather than changing the catalyst or using two reactors, was surprisingly found to allow adjustment of the broadness of the molecular weight and composition distribution. Such tunability also includes polymer structures similar to those made in the CSTR, as shown by C.Ex.2 with a RR of 24.

[0051] Not only did the samples Ex.1a-1c produced at various RRs in the SHE loop reactor exhibit broader CDs than the samples C.Ex.1 and C.Ex.2, but they also exhibited broader orthogonal composition distributions (BOCDs) as suggested by the positive slope of the CD profiles of Ex.1a-1c. BOCDs are used to illustrate the point that within a given distribution, lower molecular weight species have lower comonomer content and higher molecular weight species have higher comonomer content. Having a BOCD provides advantages in polymer performance, processing, and pellet stability, but was never achieved by a single reactor CSTR process. The ability to achieve a BOCD structure is yet another unexpected benefit of the SHE loop reactor. As a final comparison, the CD profiles of several of ExxonMobil's high viscosity Vistamaxx™ (HVV) grades (Comparative Examples 3-6) are shown in Figure 5. All were made using dual CSTR reactors except for C.Ex.6, a Vistamaxx™ 3980 sample made using a single CSTR reactor. Despite the dual reactor operation, all of these grades showed relatively uniform CD in stark contrast to the single reactor SHE samples, Ex.1a-1c.

[0052] Copolymer samples Ex.1a (RR of 9), C.Ex.2 (RR of 24), and C.Ex.1 were separately blended with commercially available PP 3155 homopolymer from ExxonMobil in a mass ratio of 80:20 (PP to C3 / C2 copolymer) to form blend compositions suitable for soft nonwoven applications. Atomic Force Microscopy (AFM) images of the blend compositions were taken. Surprisingly, the blend composition containing the copolymer sample made with a RR of 9 (Ex.1a) showed smaller particle size within the continuous PP phase than the copolymer sample made with a RR of 24 (C.Ex.2) and the CSTR sample of C.Ex.1, both of which showed larger particle size. The smaller particle size indicates a larger interfacial area between the C3 / C2 copolymer and the PP homopolymer, resulting in more favorable interactions due to the wider MWD and CD. In contrast, a larger particle size correlates with a more uniform distribution of molecules.

[0053] Example 2 Similar to the samples in Example 1, two samples (Example 2a and Example 2b) of low viscosity C3 / C2 copolymer as opposed to the high viscosity C3 / C2 copolymer were made utilizing RRs of 16 and 10, respectively. The process conditions that were varied to produce these lower molecular weight, lower viscosity samples are provided in Table 2 below.

[0054] Table 2: Process conditions for Ex.2a-2b [Table 2]

[0055] Figure 6 shows the MWD and CD graphs for samples Ex.2a-2b. As shown, the copolymer sample made with a RR of 10 (Ex.2b) exhibited a broader MWD and a broader, more positively sloping CD (indicative of BOCD) than the copolymer sample made with a RR of 16 (Ex.2a). Thus, the low viscosity C3 / C2 copolymers made using the SHE loop reactor behaved similarly to the high viscosity C3 / C2 copolymers made using the SHE loop reactor in that they exhibited broadening of MWD and CD with decreasing RR.

[0056] Example 3 A C3 / C2 copolymer sample (Example 3) was made similar to the sample of Example 1, except that the process conditions were different and instead of a single Tranter SHE reactor, two parallel SHE reactors commercially available from Alfa Laval Inc. (hereinafter "Alfa Laval SHE reactors") were utilized. The Alfa Laval SHE reactor loop has a different ratio of isothermal to adiabatic regions than the Tranter SHE reactor loop. The process conditions used to produce the sample of Ex.3 are provided below in Table 3.

[0057] Table 3: Process conditions for Ex.3 [Table 3]

[0058] FIG. 7 shows the MWD and CD plots of the C3 / C2 copolymer sample of Ex.3. For comparison purposes, FIG. 7 also shows the MWD and CD plots of Vistamaxx™ 6102 C3 / C2 copolymer samples (Comparative Examples 7 and 8) made under similar process conditions but in a different plant using dual CSTR reactors. Despite changing the heat transfer profile and SHE reactor manufacturer compared to Ex.1-2, the SHE reactor design continued to demonstrate the ability to produce a C3 / C2 polymer sample with BOCD (Ex.3). In contrast, the C.Ex.7-8 samples showed uniform CD as suggested by the near-zero slope of the CD profiles of these samples.

[0059] Example 4 Two C3 / C2 copolymer samples (Examples 4a and 4b) were prepared similarly to C.Ex.2 (RR of 24), except that sample Ex.4b was prepared using an Alfa Laval SHE reactor with different amounts of isothermal and adiabatic reaction volume. The process conditions used to prepare samples Ex.4a-4b are shown in Table 4 below.

[0060] Table 4: Process conditions for Ex.4a-4b [Table 4]

[0061] Samples of Ex.4a-4b were subjected to fractionation by high performance liquid chromatography-size exclusion chromatography (HPLC-SEC). Figure 8 shows the chromatograms of samples of Ex.4a-4b, which show that these samples have similar breadth as far as comonomer incorporation and / or sequence length distribution is concerned. This provides further evidence of the robustness of the present technique, which can produce similar distributions of products despite changes in reactor manufacturer or ratio of isothermal to adiabatic reaction volumes.

[0062] Example 5 Three C3 / C2 copolymer samples (Comparative Examples 9-10 and Ex. 5) were made similarly to the sample in Ex. 1, but utilizing an Alfa Laval SHE reactor with RRs of 12, 6, and 3, respectively. The process conditions used to make the Ex. 5 sample are shown in Table 5 below.

[0063] Table 5: Process conditions for Ex.5 [Table 5]

[0064] The MWD and CD profiles of the copolymer samples C.Ex.9-10 and Ex.5 are shown in Figure 9. Samples C.Ex.9-10 and Ex.5 showed a similar trend to samples C.Ex.2 and Ex.1a-1b in that the CD became broader (increased slope) as RR decreased, but the MWD remained almost unaffected. This trend is believed to occur because the SHE reactor temperature and monomer concentration vary significantly along the loop at lower RR, leading to intra-reactor differences in reaction kinetics and comonomer incorporation.

[0065] Example 6 The C3 / C2 copolymer sample of Ex.3 was mixed with Exxon Mobil PP homopolymer PP3155 in a Brabender at a weight ratio of 15:85 to form a blend formulation (Example 6). For comparison purposes, a blend of Vistamaxx™ 6102 made with CSTR and PP3155 was similarly prepared (Comparative Example 11). The blend could be applied to elastic films for hygiene applications such as diapers. Various physical properties, including elastic properties, of the Ex.6 and C.Ex.11 formulations were measured and are shown in Table 6 below. The melt flow rates (MFR), tensile properties, and flexural modulus of these formulations were similar, and the Ex.6 formulation (containing C3 / C2 copolymer made in a SHE loop reactor) unexpectedly demonstrated elastic enhancement by having a lower maximum load, lower load loss, lower permanent set, and less mechanical hysteresis than the C.Ex.11 formulation (containing C3 / C2 copolymer made in a CSTR).

[0066] Table 6: Properties of blends of Ex.6 and C.Ex.11 [Table 6]

[0067] The cross-sections of the blends Ex.6 and C.Ex.11 were then imaged by AFM and the images analyzed for particle size throughout the continuous PP phase. The blend Ex.6 had an average particle size of 39 nm, while the blend C.Ex.11 had a particle size of 85 nm. Surprisingly, the smaller average particle size of the blend Ex.6 suggests a more favorable interaction of the C3 / C2 copolymer with the PP phase. It is believed that the BOCD in the blend Ex.6 improved the compatibility of the copolymer with the PP homopolymer, thereby increasing the elasticity of this blend.

[0068] Example 7 Three C3 / C2 copolymer samples (Example 7, and Comparative Examples 12-13) were made in a dual reactor setup using an Alfa-Laval SHE reactor similar to the sample in Example 3, but with increasingly uniform CD. The process conditions used to make the sample in Ex. 7 are shown in Table 7 below.

[0069] Table 7: Process conditions for Ex.7 [Table 7]

[0070] The MWD and CD profiles of samples C.Ex.7 and C.Ex.12-13 are shown in Figure 10. For comparison purposes, the MWD and CD profiles of a Vistamaxx™ 6102 sample (Comparative Example 14) made using a conventional CSTR process are also shown in Figure 10. Comparison of the CD profile of the sample with the most uniform CD (C.Ex.13) with that of sample C.Ex.14 reveals that the SHE loop reactor encompasses the ability of the CSTR to produce uniform CD as required. Thus, the SHE loop reactor surprisingly offers tunability of both MWD and CD.

[0071] Example 8 Three C3 / C2 copolymer samples (Example 8 and Comparative Examples 15-16) were made similar to the samples in Example 1, except that the CD was controlled to have an opposite gradient (negative gradient). Sample Ex. 8 was made with approximately 1 wt% less C2 than sample C.Ex. 15, and sample C.Ex. 16 was made with approximately 2 wt% less C2 than sample C.Ex. 15. The process conditions used to make the samples in Ex. 8 are shown in Table 8 below.

[0072] Table 8: Process conditions for Ex.8 [Table 8]

[0073] 11 graphically illustrates the MWD and CD of samples Ex.8 and C.Ex.15-16, as well as the MWD and CD of Vistamaxx™ 6200 samples (Comparative Examples 17 and 18) produced using a CSTR process at a different ExxonMobil plant. As shown in Table 9, the negative CD slopes of samples Ex.8 and C.Ex.15-16 demonstrate the versatility of the SHE reactor process disclosed herein.

[0074] Table 9: Quantification of CD gradient for Ex.8 and C.Ex.15-18 copolymers [Table 9]

[0075] Example 9 For comparison with the C3 / C2 copolymer sample of Ex.1a (RR of 9), the following PP random copolymers (RCPs) made with Ziegler-Natta (ZN) catalysts were obtained: PP9074MED commercially available from ExxonMobil (Comparative Example 19); RJ766MO commercially available from Borealis AG (Comparative Example 20); and Pro-fax RP311H sold by LyondellBasell Industries (Comparative Example 21). Figure 12 shows the MWD and CD profiles of each of these samples. The RCP samples made with ZN catalysts had a CD substantially different from that of the inventive sample of Ex.1a. The RCP samples of C.Ex.19-21 showed a decrease in comonomer content with increasing M, rather than having a BOCD like the sample of Ex.1a. The inventive sample of Ex.1a had a PDI of 2.6, which in turn was broader than the MWD of conventional metallocene products, which typically have a PDI of 2.0-2.2. Furthermore, the inventive sample of Ex.1a had a narrower MWD than the MWD of the RCP samples C.Ex.19-21 produced with ZN catalysts. Conventional RCPs produced with metallocene catalysts also typically exhibit a flat CD profile, indicative of a uniform CD, as opposed to the non-uniform broad CD exhibited by the inventive propylene-based copolymers disclosed herein.

[0076] Example 10 CD Slope 25, CD Slope 50, and CD Slope 75 were calculated for each C3-based copolymer of the invention, characterized by a broad orthogonal comonomer distribution. The same calculations were performed for the comparative copolymers and overlaid in Figures 4, 7, 9, and 10, as well as for the additional comparative copolymers shown in Figure 5. The results are shown in Table 10 below. Various properties of certain example and comparative copolymers were also determined, as shown in Table 11 below.

[0077] Table 10: Quantification of CD gradient for copolymers of specific examples [Table 10]

[0078] Table 11: Properties of copolymers of specific examples [Table 11]

[0079] Test procedure In all the preceding examples, melt index (MI) measured at 190° C. and 2.16 kg and MFR measured at 230° C. and 2.16 kg were obtained according to ASTM D1238. Tensile properties were measured according to ASTM D637 and flexural modulus was measured according to ASTM D790, procedure B. Brookfield viscosity was measured at 190° C. using a Brookfield Thermosel viscometer according to ASTM D-3236.

[0080] GPC-4D Unless otherwise indicated, molecular weight distributions and moments (e.g., Mw, Mn, Mw / Mn) and comonomer content were determined using high temperature gel permeation chromatography (Polymer Char GPC-IR) equipped with a multiple channel band filter based infrared detector IR5, an 18-angle light scattering detector, and a 4-capillary viscometer. Three Agilent Plgel 10 μm Mixed-B LS columns were used to effect polymer separation. Aldrich reagent grade 1,2,4-trichlorobenzene (TCB) containing 300 ppm of the antioxidant butylated hydroxytoluene (BHT) was used as the mobile phase. The TCB mixture was filtered through a 0.1 μm Teflon filter and degassed with an online degasser before entering the GPC instrument. The nominal flow rate was 1.0 mL / min and the nominal injection volume was 200 μL. The entire system, including the transfer lines, columns, and detectors, was housed in an oven maintained at 145° C. The polymer samples were weighed and sealed in standard vials containing heptane flow markers for flow rate correction. After loading the vials into the autosampler, the polymers were dissolved in 8 mL of TCB solvent, which was automatically filled into the vials, at 160 °C for about 1 or 2 hours with continuous shaking. The polymer concentration at each point of the chromatogram was calculated from the baseline subtracted IR5 broadband signal intensity multiplied by a mass constant calibrated with polystyrene standards. The mass recovery was calculated from the ratio of the calculated mass corresponding to the integrated area of ​​the concentration chromatography over the elution volume to the injected mass equal to the predetermined concentration multiplied by the injection loop volume. The typical molecular weight was determined by combining the universal calibration relationship with a column calibration performed with a series of monodisperse polystyrene (PS) standards ranging from 700 g / mol to 10,000,000 g / mol. The MW at each elution volume was calculated by the following equation (1):

number

[0081] where the variables with the subscript "PS" represent polystyrene and the variables without a subscript represent the test sample. PS = 0.67 and KPS = 0.000175, and α and K for ethylene-propylene copolymers are calculated from α = 0.695 + (0.01 * (mass fraction propylene)) and K = 0.000579 - (0.0003502 * (mass fraction propylene)). Specifically, for ethylene polymers, α = 0.695 and K = 0.000579, and for propylene polymers, α = 0.705 and K = 0.0002288. Concentrations are in g / cm unless otherwise noted. 3 the molecular weight is expressed in g / mol, and K in the Mark-Houwink equation is expressed in dL / g. The comonomer composition was determined by the ratio of the IR5 detector intensities corresponding to the CH3 and CH2 channels, calibrated with a series of PE and PP homopolymer / copolymer standards (these nominal values ​​were determined by NMR or FTIR). In particular, this gave the methyls per 1,000 total carbons (CH3 / 1000TC) as a function of molecular weight. Since each short chain branch (SCB) has one methyl group, the SCB content per 1000TC (SCB / 1000TC) is the same as CH3 / 1000TC. The mass % propylene as a function of molecular weight was calculated from the following expression, where:

number

number

[0082] Then, mass% C2 is obtained from 100-mass% C3. The bulk C2 composition of the polymer was obtained by considering the total signal in the CH3 and CH2 channels between the integration limits of the concentration chromatogram, and the bulk SCB / 1000TC was calculated as above.

number

number

[0083] where ΔR(θ) is the excess Rayleigh scattering intensity measured at the scattering angle θ, c is the polymer concentration determined from the IR5 analysis, A2 is the second virial coefficient, P(θ) is the monodisperse random coil form factor, and K o are the optical constants of the system:

number

[0084] where NA is Avogadro's number and (dn / dc) is the refractive index increment for the system. The refractive index n=1.500 for TCB at 145° C. and λ=665 nm. For purposes of this disclosure and the claims thereto, dn / dc=0.1048 and A2=0.0015-(0.001*(mass fraction propylene)) for propylene copolymers.

[0085] SGIC Solvent Gradient Interaction Chromatography (SGIC) (also called "HPLC-SEC") analysis was performed using a commercially available SGIC-2D instrument from Polymer Char, SA, Valencia, Spain. The principle of SGIC-2D analysis is described in the article Bhati, S. et al. Polyolefins J. 2016, 3, 119. In particular, the schematic instrumentation shown in Figure 1(a) of this article is an appropriate depiction of the schematic diagram for the apparatus used in this case. The relevant features of the apparatus and the details related to the analytical method, as applicable to this case, are as follows. An IR5 infrared detector commercially available from Polymer Char was used to generate an absorbance signal proportional to the polymer concentration in the elution stream. The composition signal for the methyl content was measured as described in the article Ortin, A. et al. Chromatogr. A 2012, 1257, 66. A Hypercarb™ column with dimensions 10.5×100 mm (ID×L.) commercially available from Thermo Fisher™ and a stationary phase of porous graphitic carbon (PGC) particles (5 μm, particle size; 138.2 m2 / gm, surface area) was used in the first dimension. A PL Rapide H SEC column with dimensions 7.5×150 mm (ID×L.) (commercially available from Agilent Technologies) packed with 10 μm particles was used in the second dimension.

[0086] The solvents used to prepare the sample solution and for elution were 98+% 1 decanol and ≥99% 1,2,4-trichlorobenzene (TCB) as the adsorption-promoting and desorption-promoting mobile phases, respectively; decanol was used as received, whereas TCB was filtered using a membrane filter (0.1 μm JV) commercially available from Omnipore™. At the beginning of the analysis, the PGC column was filled with 100 vol% decanol. The temperatures of the PGC and SEC columns were maintained at 170°C and 160°C, respectively, throughout the analysis. The samples to be analyzed (1-11 mg) were dissolved in 8 ml of decanol (weighed at ambient temperature) by shaking at 160°C for 90 min (Medium setting). A small amount of the polymer solution was first filtered through an in-line filter (stainless steel, 10 μm) with backflushing after every filtration. The filtrate was then used to completely fill the 100 μl injection valve loop. The injection valve was then switched so that the flow from the gradient pump carried the volume in the loop towards the PGC column, where this valve switching was timed to coincide with the start of the solvent gradient profile as shown below as a sequence of time (min): TCB (vol%): 0, 0; 150, 30; 170, 30; 190, 50; 200, 100; 300, 100. The flow rates used for the PGC and SEC columns were set at 0.025 ml / min of mixed solvent (gradient pump) and 3 ml / min of TCB (isocratic pump), respectively, from the start to the end of the gradient profile. The transfer valve loop volume was 100 μl and the valve switching time was 2 min, thereby filling the loop to 50 μl for each SEC injection, generating 150 SEC chromatograms per analytical sample. The resulting data was processed using an in-house MATLAB application to set baselines (for subtraction) and integration limits, calibrate the IR5 detector and SEC column, and calculate all relevant metrics from the processed data. Thirty-nine polyolefin samples with CH3 / 1000TC ranging from 0 to 333.3 were used to calibrate the CH3 / CH2 band ratio of the IR5 detector to obtain the CH3 / 1000TC signal. Nine narrow polystyrene standards (commercially available from Agilent Technologies) with peak molecular weights ranging from 1 to 6035 kg / mol were used to calibrate the elution volume from the SEC column to obtain the molecular weight of the eluted polymer.

[0087] Elastic Hysteresis A Wabash Genesis controlled cooling compression molding press was used to mold sheets with final thicknesses ranging from 8 to 12 mils (0.2 to 0.3 mm). The press temperature was increased to 180°C before inserting the samples. The samples were preheated under contact pressure for 8 minutes. Compression was then applied at 180°C for 5 minutes followed by controlled cooling. Three test specimens were cut from the resulting molded sheets with a sharp scalpel blade into strips 150 mm long and 50 mm wide. The specimens were conditioned at 23°C ± 2°C and 50% ± 10% relative humidity for a minimum of 40 hours prior to testing. An Instron tensile tester (Instron® 5566) was used for elastic hysteresis testing. Each specimen was placed in the grips with a grip separation of 100 mm. The specimen was extended to 100% elongation with a crosshead speed of 500 mm / min. The crosshead was returned to 0% elongation and the cycle was repeated once more. In summary, three specimens per material were examined and average values ​​for the following elastic properties were reported on a one-cycle basis: load at 50% strain, maximum load, retraction force, load loss, permanent set, and mechanical hysteresis. The load at 50% strain is the force measured on the ascending curve at 50% strain. The maximum load is the force measured on the ascending curve at 100% strain. The compression force is the force measured at 50% strain on the descending curve as the specimen unloads. The load loss was calculated as (force on ascending curve-force on descending curve) / force on ascending curve at 50% strain and is given as a percentage. Permanent set is the percent strain corresponding to a force of 0.1 N on the descending curve. Mechanical hysteresis is obtained as a percentage by dividing the area enclosed by the ascending and descending curves by the total area under the ascending curve.

[0088] CD gradient Comonomer distribution is expressed as CD slope 25, 50, and 75, calculated from the slope of the comonomer distribution curve estimated at 25%, 50%, and 75% of the highest log molecular weight value, respectively. The slope was determined by first curve fitting the comonomer content versus molecular weight change to an nth degree polynomial using the MATLAB® program. The value of n ranges from 2 to 4. The derivatives of the curve were obtained at various molecular weight points, which are 25%, 50%, and 75%, respectively, of the molecular weight range. For example, to determine the 25% point on the x-axis, the difference between the minimum molecular weight (mwmin) and the maximum molecular weight (mwmax) of a particular data set was first established. The x value of slope 25 was calculated as mwmin+0.25*(mwmax-mwmin). The derivative was determined at that point to find the CD slope 25. The CD slope was calculated only between slope 20 and slope 80. The CD slope at any single point between slope 20 and slope 80 was referred to herein as the "CD slope 20-80." Having all CD slope values ​​in the range of -1 to 1 was considered to represent a uniform comonomer distribution, while having all CD slope values ​​>1.5 was considered to represent a broad orthogonal comonomer distribution (BOCD).

[0089] LIST OF EMBODIMENTS The present disclosure may further include any one or more of the following non-limiting embodiments. 1. A process for the production of propylene-based copolymers, comprising introducing propylene and at least one other olefin comonomer into a tubular reactor to produce a broad comonomer distribution, an M of about 10 kg / mol to about 2,000 kg / mol. W and producing a propylene-based copolymer having an MWD of about 2.0 to about 10.0. 2. The process of embodiment 1, wherein the propylene-based copolymer comprises a broad orthogonal comonomer distribution. 3. The process of any one of the preceding claims, wherein the broad orthogonal comonomer distribution comprises a comonomer distribution (CD) slope 20-80 of from about 1.5 to about 30.0. 4. The process of any one of embodiments 1 to 3, wherein the tubular reactor comprises one or more tubular reactors, each tubular reactor comprising a recirculation pump. 5. The process of embodiment 4, wherein each tubular reactor contains one or more heat exchanger elements. 6. The process of embodiment 5, wherein at least one of the heat exchanger elements is a spiral heat exchanger. 7. The process of embodiment 5, wherein the propylene-based copolymer is produced at a recycle rate of from about 0.1 to about 50.0. 8. The process of embodiment 5, wherein the propylene-based copolymer is produced at a recycle rate of from about 3.0 to about 15.0. 9. The process of embodiment 5, wherein the recycle rate is varied and the monomer conversion is constant as the propylene-based copolymer is produced. 10. The process as described in embodiment 5, wherein the recycle rate is constant and the monomer conversion varies along the axial length of each tubular reactor as the propylene-based copolymer is produced. 11. The process of any one of the preceding embodiments, wherein the propylene-based copolymer is produced at a cement concentration of about 2 wt% to about 40 wt%. 12. The process of any one of the preceding embodiments, further comprising introducing a catalyst system into the tubular reactor. 13. The process of any of the preceding embodiments, wherein propylene and at least one other olefin comonomer are copolymerized using a continuous solution polymerization process. 14. The process of any of the preceding embodiments, wherein the at least one other olefin comonomer comprises ethylene, a C4-C20 olefin, or a combination thereof. 15. The process of any of the preceding embodiments, wherein the propylene-based copolymer has an MFR of about 0.1 g / 10 min to about 1,000 g / 10 min according to ASTM D1238, or a Brookfield viscosity of about 400 to 50,000 cP according to ASTM D-3236.

[0090] 16. A propylene-based copolymer composition comprising propylene-derived units and at least one other comonomer-derived unit, comprising a broad comonomer distribution, an M of about 10 kg / mol to about 2,000 kg / mol. Wand a MWD of about 2.0 to about 10.0. 17. The propylene-based copolymer composition according to embodiment 16, wherein the copolymer composition has a broad orthogonal comonomer distribution. 18. The propylene-based copolymer composition of embodiment 16 or 17, wherein the broad orthogonal comonomer distribution comprises a comonomer distribution (CD) slope 20-80 of about 1.5 to about 30.0. 19. The propylene-based copolymer composition according to any of embodiments 16-18, wherein the at least one other olefin comonomer comprises ethylene, a C4-C20 olefin, or a combination thereof. 20. The propylene-based copolymer composition of any of embodiments 16-19, wherein the copolymer composition has an MFR according to ASTM D1238 of about 0.1 g / 10 min to about 1,000 g / 10 min or a Brookfield viscosity according to ASTM D-3236 of about 400 to 50,000 cP. 21. A nonwoven fabric, a film, a plastic piping, a plastic bag, a cable, or a solar cell comprising the propylene-based copolymer composition according to embodiment 16.

[0091] Certain embodiments and features have been described with a set of upper numerical limits and a set of lower numerical limits. It should be understood that ranges including any combination of two values ​​are contemplated, for example, any combination of a lower limit with any upper limit, any combination of two lower limits, and / or any combination of two upper limits, unless otherwise indicated. Certain lower limits, upper limits and ranges appear in one or more claims below. All numerical values ​​are "about" or "approximately" designations and take into account experimental error and variations that would be expected by one of ordinary skill in the art. Various terms have been defined above. Unless a term used in the claims is defined above, it should be given the broadest definition that one skilled in the art would give that term as reflected in at least one publication or issued patent. Furthermore, all patents, test procedures, and other documents cited in this application are incorporated by reference in their entirety to the extent that their disclosures are not inconsistent with this application, and for all authorities to which such incorporation is permitted. While the forgoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, the scope of which is determined by the claims that follow.

Claims

1. A process for the production of propylene-based copolymers, comprising introducing propylene and at least one other olefin comonomer into a tubular reactor to produce a broad comonomer distribution, an M of about 10 kg / mol to about 2,000 kg / mol. W and producing a propylene-based copolymer with an MWD of about 2.0 to about 10.

0.

2. 2. The process of claim 1, wherein the propylene-based copolymer comprises a broad orthogonal comonomer distribution.

3. 3. The process of claim 1 or 2, wherein the broad orthogonal comonomer distribution comprises a comonomer distribution (CD) slope 20-80 of about 1.5 to about 30.

0.

4. 4. The process of any one of claims 1 to 3, wherein the pipe reactor comprises one or more pipe reactors, each of which comprises a recirculation pump.

5. 5. The process of claim 4, wherein each of the tubular reactors comprises one or more heat exchanger elements.

6. 6. The process of claim 5, wherein at least one of the heat exchanger elements is a spiral heat exchanger.

7. 6. The process of claim 5, wherein the propylene-based copolymer is produced at a recycle ratio of about 0.1 to about 50.

0.

8. 6. The process of claim 5, wherein the propylene-based copolymer is produced at a recycle ratio of about 3.0 to about 15.

0.

9. 6. The process of claim 5, wherein the recycle rate is varied and the monomer conversion is constant as the propylene-based copolymer is produced.

10. 6. The process of claim 5, wherein the recycle rate is constant and the monomer conversion varies along the axial length of each of the tubular reactors as the propylene-based copolymer is produced.

11. The process of any one of claims 1 to 10, wherein the propylene-based copolymer is produced at a cement concentration of about 2 wt% to about 40 wt%.

12. The process of any one of claims 1 to 11, further comprising the step of introducing a catalyst system into the tubular reactor.

13. The process of any one of claims 1 to 12, wherein the propylene and the at least one other olefin comonomer are copolymerized using a continuous solution polymerization process.

14. 14. The process of any one of claims 1 to 13, wherein the at least one other olefin comonomer comprises ethylene, a C4-C20 olefin, or a combination thereof.

15. 15. The process of any one of claims 1 to 14, wherein the propylene-based copolymer has a MFR of about 0.1 g / 10 min to about 1,000 g / 10 min according to ASTM D1238, or a Brookfield viscosity of about 400 to 50,000 cP according to ASTM D-3236.

16. A propylene-based copolymer composition comprising propylene-derived units and at least one other comonomer-derived units, said composition having a broad comonomer distribution, an M of about 10 kg / mol to about 2,000 kg / mol. W and a MWD of about 2.0 to about 10.

0.

17. 17. The propylene-based copolymer composition of claim 16, wherein the copolymer composition has a broad orthogonal comonomer distribution.

18. 18. The propylene-based copolymer composition of claim 16 or 17, wherein the broad orthogonal comonomer distribution comprises a comonomer distribution (CD) slope 20-80 of about 1.5 to about 30.

0.

19. The propylene-based copolymer composition of any one of claims 16 to 18, wherein the at least one other olefin comonomer comprises ethylene, a C4-C20 olefin, or a combination thereof.

20. 20. The propylene-based copolymer composition according to any one of claims 16 to 19, wherein the copolymer composition has an MFR of about 0.1 g / 10 min to about 1,000 g / 10 min according to ASTM D1238 or a Brookfield viscosity of about 400 to 50,000 cP according to ASTM D-3236.

21. 17. A nonwoven fabric, a film, a plastic piping, a plastic bag, a cable, or a solar cell comprising the propylene-based copolymer composition of claim 16.

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