Enhanced polymer devolatilization via controlled foaming

Abstract

A system and method for devolatilizing low-viscosity polymers includes providing a reaction mixture containing a polymer and one or more volatile materials, the one or more volatile materials including one or more unreacted monomers and at least one hydrocarbon solvent; separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase into a vapor hydrocarbon phase and a concentrated polymer phase in a second separator; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds in a separator conduit positioned between the second separator and the third separator.

Description

[Technical Field]

[0001] Inventor: Hamidreza Khakdaman, Andrew Takacs, Michael K. Lyon, Keishla R. Rivera Dones, Rong Ma, Vetkav R. Eswaran, Giriprasath Gururajan

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 476,390, filed December 21, 2022, the entire contents of which are incorporated herein by reference. Systems and methods are provided for polymer resin devolatilization. More particularly, systems and methods are provided herein for devolatilizing polyalphaolefins made into solution. [Background technology]

[0003] Solution polymerization is one of many methods by which polymerization can be carried out on an industrial scale. In a solution polymerization process, monomers are reacted in the presence of a catalyst and a solvent, typically a solvent that does not react with the catalyst or the monomers. The resulting monomers and polymer from the polymerization reaction are solubilized in the reactor by the solvent. The heat released by the reaction is absorbed by the solvent and removed by various methods, including, but not limited to, chilled feed, reflux cooling, cooling jackets, and heat exchangers. The effluent leaving the reactor is a mixture of polymer, solvent, and unconverted monomer. The polymer is separated from the remainder of the effluent, i.e., the solvent and unconverted monomer. The polymer is then pelletized to form small pellets, dried, and bagged. Continuously stirred tank reactors (CSTRs) and non-adiabatic loop reactors are examples of reactors that can be used in solution polymerization processes. The polymer product is separated from the solvent and unreacted monomers in a polymer devolatilization unit (Devol unit), which is a multi-stage process with varying process conditions. As the polymer solution passes through the various stages of the Devol unit, the polymer concentration increases and the solvent and monomer concentrations decrease. The maximum amount of devolatilization at each stage is governed (i.e., limited) by equilibrium conditions at specific temperatures and pressures. The goal is to produce a polymer product with the lowest amount of volatile organic compounds (VOCs) at the parts per million level.

[0004] Each stage of the Devol unit requires sufficient heat of vaporization, maximum liquid-vapor interface, and time at a specific temperature and pressure. Generally, a significant amount of solvent and monomer is separated from the polymer in the early stages of the Devol unit. The amount of solvent separated at each stage is determined by the operating temperature and pressure of each stage. Higher temperatures and lower pressures result in higher devolatilization rates and therefore lower solvent concentrations in the polymer product. In the final stage of the Devol unit, the polymer solution has the lowest solvent concentration, minimizing the devolatilization rate. This is because the separation process is limited by the solvent mass transfer rate through the polymer, which is a very slow phenomenon. To increase the mass transfer rate, it is necessary to increase the interface between the solvent and polymer. One way to increase the interface between the solvent and polymer is by using a distributor that spreads the polymer solution in a low-pressure vessel. However, such distributors are limited by practicality and do not provide a large enough surface-to-volume ratio in an economical manner. In other words, to increase the surface area-to-volume ratio, the vessel and distributor size must be very large and the distributor holes must be very small, which is limited by the pressure drop across the holes.

[0005] Another approach to increasing the solvent-polymer interface is to generate bubbles or foam in the polymer solution. The thin film of liquid that creates bubbles and foam significantly increases the surface-to-volume ratio. Generating bubbles and foam in polymer solutions containing high molecular weight polymers is easily induced within the typical process operating window of the conventional Devol process (e.g., T = 140-210 °C; P = 10-50 Torr). However, foam formation is not easy in the case of low molecular weight (low viscosity) polymers due to their low melt strength. Therefore, there is a need for new systems and methods for devolatilizing low molecular weight (low viscosity) polymers that have low melt strength. Summary of the Invention

[0006] A system and method for devolatilizing low-viscosity polymers having low melt strength is provided. In one embodiment, the method includes providing a reaction mixture containing a polymer and one or more volatile materials, the one or more volatile materials including one or more unreacted monomers and at least one hydrocarbon solvent; separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase into a vapor hydrocarbon phase and a concentrated polymer phase in a second separator; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds in a separator conduit positioned between the second separator and the third separator.

[0007] In another embodiment, a method includes providing a reaction mixture comprising a polymer having a Brookfield viscosity of less than 40,000 cP and a weight average molecular weight (Mw) of less than 62,000 g / mol as determined by GPC, and one or more volatile materials, the one or more volatile materials comprising one or more unreacted monomers and at least one hydrocarbon solvent; separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase into a vapor hydrocarbon phase and a concentrated polymer phase in a second separator; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds in a separator conduit positioned between the second separator and the third separator.

[0008] In another embodiment, a method includes providing a reaction mixture comprising a polymer having a Brookfield viscosity of less than 40,000 cP, a weight average molecular weight (Mw) of less than 62,000 g / mol as determined by GPC, and an MFR (ASTM D1238) of 500 to 40,000 g / 10 min, and one or more volatile materials, the one or more volatile materials comprising one or more unreacted monomers and at least one hydrocarbon solvent; separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase into a vapor hydrocarbon phase and a concentrated polymer phase in a second separator; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds at third separator conditions in a separator conduit positioned between the second separator and the third separator.

[0009] In one embodiment, the system includes a first separator for separating a reaction mixture comprising a polymer and one or more volatile materials into a polymer-rich phase and a polymer-lean phase, the one or more volatile materials comprising one or more unreacted monomers and at least one hydrocarbon solvent; a second separator for separating the polymer-rich phase into a vapor hydrocarbon phase and a concentrated polymer phase; a third separator for removing at least a portion of the volatile materials from the concentrated polymer phase; and a separator conduit positioned between the second separator and the third separator, the separator conduit configured to provide a residence time therein of about 0.2 seconds to 10 seconds. These and other features and attributes of the present disclosure, as well as their advantageous applications and / or uses, will become apparent from the following detailed description. To assist those skilled in the relevant art in making and using the present subject matter, reference is made to the accompanying drawings, in which: [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows an exemplary process flow diagram of a devolatilization unit according to one or more embodiments provided herein. [Figure 2] FIG. 2 shows an enlarged schematic view of an exemplary vacuum flash drum that can be used as the third stage flash drum shown in FIG. 1 according to one or more embodiments provided herein. [Figure 3] 3 shows an enlarged schematic view of a polymer solution supply assembly 300 for entering the flash drum 130 shown in FIG. 2 according to one or more embodiments provided herein. [Figure 4] 4 shows an expanded schematic view of an alternative polymer solution feed segment 400 for entering the flash drum 130 shown in FIG. 2 according to one or more embodiments provided herein. [Figure 5] 3 shows a schematic diagram of the vacuum flash drum 130 of FIG. 2 that can be configured to utilize multiple feed assemblies 300 and / or 400 according to one or more embodiments provided herein. [Figure 6] 1 shows the VOC HSGC obtained from the examples plotted against the equilibrium HSGC. DETAILED DESCRIPTION OF THE INVENTION

[0011] Provided herein are systems and methods for devolatilizing low-viscosity polymers with low melt strength. It has been unexpectedly and surprisingly discovered that low-viscosity polymers with low melt strength can be devolatilized to equilibrium with VOCs at conventional operating temperatures and pressures of end-stage devolatilizers. According to one or more embodiments provided herein, low viscosity polymers (i.e., Brookfield viscosity less than 40,000 cP, melt flow rate (MFR) of 500 to 40,000 g / 10 min (ASTM D1238) and / or zero shear viscosity less than 200 Pa·s (at 190°C and 0.1 s)) can be devolatilized to equilibrium with VOCs. -1 Polymers with a molecular weight (Mw) of less than 62,000 g / mol (measured at a frequency of 1000 Hz) and low molecular weight (i.e., Mw less than 62,000 g / mol) can be sufficiently devolatilized by creating a foam or bubbles during the final stages of devolatilization. Controlled foaming can be created and maintained to reduce the VOC of the polymer to the lowest concentration thermodynamically possible at a given temperature and pressure. "Foam" refers to process solvent dissolved in a low viscosity polymer with low melt strength that becomes volatilized, forming a light, frothy mass of bubbles or gas pockets containing evaporating hydrocarbons within or on the surface of the polymer.

[0012] Low viscosity polymers with low melt strength have a Brookfield viscosity of 300 cP to 40,000 cP, a melt flow rate (MFR) (ASTM D1238) of 500 to 40,000 (g / 10 min), and / or a zero shear viscosity of less than 200 Pa·s (at 190°C and 0.1 s -1The Brookfield viscosity may range from as low as about 300 cP, 400 cP, 600 cP, or 1,000 to as high as 3,000 cP, 10,000 cP, 15,000 cP, or 40,000 cP. The MFR may range from as low as about 500 g / 10 min, 1,000 g / 10 min, or 2,000 g / 10 min to as high as 3,000 g / 10 min, 15,000 g / 10 min, 25,000 g / 10 min, or 40,000 g / 10 min. Low viscosity polymers with low melt strength also have a low weight average molecular weight (Mw), for example, a weight average molecular weight of less than 62,000 g / mol, less than 56,000 g / mol, less than 46,000 g / mol, less than 36,000 g / mol, or less than 26,000 g / mol.

[0013] It has been unexpectedly and surprisingly discovered that low-viscosity polymers with low melt strength, such as a Brookfield viscosity of less than 40,000 cP, a MFR greater than 500 g / 10 min, and / or a zero-shear viscosity less than 200 Pa·s, can be sufficiently devolatilized to the lowest equilibrium VOC concentration at a given temperature and pressure. Such low-viscosity polymers may be elastomers, plastomers, thermoplastics, thermoplastic elastomers, or other types of elastomeric polymers. Such low-viscosity polymers may also be polyolefins, such as polypropylene, propylene-based polyolefins, polyethylene, ethylene-based polyolefins, polystyrene, or combinations thereof. Preferred polyolefins are copolymers or terpolymers with dienes or other polar comonomers, including silane-modified polyethylene, ethylene vinyl acetate, ethylene acrylate, and organic acid-modified polyethylene. The low viscosity polymers may be propylene-rich (>50 wt. % C3) or ethylene-rich (>50 wt. %) with comonomer units derived from ethylene or higher alpha olefins from C4 to C40 with insertions in a random or blocky mode.

[0014] It should be understood that the systems and methods described herein are equally suitable for devolatilizing polymers derived from any liquid phase polymerization process. For example, the polymer to be devolatilized can be derived from high-pressure fluid, slurry, bulk, or solution phase polymerization processes, or combinations thereof. However, for simplicity and ease of description, the embodiments provided herein for devolatilizing low melt strength polymers will be further described with reference to polymers made using solution polymerization techniques. It should also be understood that the following disclosure describes several exemplary embodiments for implementing various features, structures, and / or functions of the present invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the disclosure; however, these exemplary embodiments are provided by way of example only and are not intended to limit the scope of the present invention. Furthermore, the present disclosure may repeat reference numerals and / or letters in various exemplary embodiments and throughout the figures presented herein. This repetition is for the purposes of simplicity and clarity and does not in itself indicate a relationship between the various exemplary embodiments and / or configurations discussed in the figures. Furthermore, the exemplary embodiments presented below may be combined in any combination manner, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment without departing from the scope of the present disclosure.

[0015] Furthermore, certain terms are used throughout the following description and claims to refer to particular components. Those skilled in the art will understand that various entities may refer to the same component by different names, and therefore the naming conventions for the components described herein are not intended to limit the scope of the invention unless otherwise specified herein. Furthermore, the naming conventions used herein are not intended to distinguish between components that differ in name but not function. In the discussion below and in the claims, the terms "including" and "comprising" are intended to be open-ended and should therefore be interpreted to mean "including, but not limited to." The phrase "consisting essentially of" means that the described / claimed composition does not contain any other components that would materially alter its properties by more than 5%, and in any case does not contain any other ingredient to a level greater than 3% by weight.

[0016] 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 herein. The indefinite articles "a" and "an" refer to both singular (i.e., "one") and plural referents (i.e., one or more) unless the context clearly dictates otherwise. For example, an embodiment using "an olefin" includes embodiments in which one, two, or more olefins are used, unless specified to the contrary or the context clearly dictates that only one olefin is used.

[0017] The term "wt%" means mass percentage, "vol%" means volume percentage, "mol%" means mole percentage, "ppm" means parts per million, and "ppm wt" and "wppm" are used interchangeably and mean parts per million by weight. All concentrations herein are expressed relative to the total amount of the composition in question unless otherwise stated. The term "polymer" refers to any two or more of the same or different repeating / merizing units or units. The term "homopolymer" refers to a polymer having the same units. 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 referring to units indicates that the units differ from each other by at least one atom or are isomerically different. 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% to 30% by weight, it is understood that the repeating and / or merizing units or simply units in the copolymer are derived from propylene in the polymerization reaction, and that the derived units are present at 10% to 30% by weight, based on the weight of the copolymer.

[0018] As used herein, "Mn" refers to the number average molecular weight of the various polymers in a polymeric material, "Mw" refers to the weight average molecular weight of the various polymers in a polymeric material, and "Mz" refers to the z-average molecular weight of the various polymers in a polymeric material. The terms "molecular weight distribution" (MWD) and "polydispersity index" (PDI) are used interchangeably to refer to the ratio of Mw to Mn. Unless otherwise stated, all molecular weights (e.g., Mw, Mn, Mz) are reported in g / mol. 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 periodic table is shown on the inside cover page of Advanced Inorganic Chemistry, 6th Edition, F. Albert Cotton et al. (John Wiley & Sons, Inc., 1999).

[0019] As used herein, "polymer" can refer to homopolymers, copolymers, interpolymers, terpolymers, etc. When a polymer is said to contain a monomer, the monomer is present in the polymer in the polymerized form of the monomer or in a derived form of the monomer. Thus, when a polymer is said to contain a certain percentage (e.g., weight %) of a monomer, that percentage of monomer is relative to the total amount of monomer units in all polymer components of the composition or blend. That is, a polymer containing 30 weight % ethylene and 70 weight % propylene is a polymer in which 30 weight % of the polymer is ethylene-derived units and 70 weight % of the polymer is propylene-derived units. As used herein, "solution polymerization" refers to a polymerization process that occurs in the presence of a liquid polymerization system, such as an inert solvent or monomers or a blend thereof, in which the polymer produced is soluble. Solution polymerization involves a homogeneous liquid polymerization system within a reactor. Homogeneous polymerization processes are typically those in which at least 90% by weight, e.g., at least 95%, at least 98%, or 100% by weight, of the product is soluble in the reaction medium. The temperature of the liquid polymerization system is below its supercritical or pseudo-supercritical temperature; therefore, solution polymerization is carried out below the supercritical temperature and / or pressure of the system.

[0020] As used herein, "polymer concentration" is the weight percent of polymer relative to the total weight of the solution mixture. As used herein, "monomer concentration" is the weight percent of monomer relative to the total weight of the solution mixture. As used herein, "melt flow rate" is the ability of a polymer to flow for a finite time interval. The melt flow rate of a polymer is calculated as the mass per 10 minutes that passes through a melt flow tester at a standard temperature.

[0021] FIG. 1 shows an exemplary process flow diagram of a devolatilization unit 100 according to one or more embodiments provided herein. Devolatilization unit 100 ("Devol unit") includes any number of separators or flash drums (three are shown at 110, 120, and 130). Reactor effluent enters first flash drum 110 via stream or conduit 102. Reactor effluent stream 102 is a polymer solution and contains varying amounts of polymer, solvent, and other unconverted monomers. The reactor effluent may have a polymer mass fraction ranging from about 1% to about 75% by weight, e.g., from about 2% to about 50% by weight, or from about 5% to about 40% by weight, or from about 7% to about 35% by weight, with the remainder adding up to 100% being volatile organic compounds ("VOCs"). The VOCs in reactor effluent stream 102 are solvent, any unconverted monomers, and any other free hydrocarbons. Each flash drum 110, 120, 130 operates at a specific temperature and pressure to maximize vapor-liquid or liquid-liquid separation within it. For example, the first flash drum 110 can operate at a temperature of 100-160°C and a pressure of 70-700 psig. The second flash drum 120 can operate at a temperature of 130-180°C and a pressure of 30-60 psig. The third flash drum 130 can operate at a temperature of 130-220°C and a pressure of 10-50 Torr.

[0022] In the first flash tank or flash unit 110, most of the unreacted monomer, comonomer, and solvent (i.e., volatiles) are separated from the polymer. In the second flash tank or flash unit 120, the temperature and pressure conditions are changed to allow further separation of the remaining volatiles from the polymer. And in the third flash tank or flash unit 130, the temperature and pressure conditions are changed again to further separate any remaining volatiles from the polymer to meet the desired volatiles specification in the parts per million range. For example, polymer stream 114 exiting first separation drum 110 and entering second flash drum 120 may contain anywhere from 30% to 60% by weight polymer and anywhere from 40 to 70% by weight volatile organic compounds (“VOCs”). Polymer stream 124 exiting second flash drum 120 and entering third flash drum 130 may contain anywhere from 85% to 95% by weight polymer and anywhere from 5 to 15% by weight volatile organic compounds (“VOCs”). Polymer stream 134 exiting third flash drum 130 may contain less than 2,000 ppmw of volatile organic compounds (“VOCs”), e.g., less than 1,800 ppmw, 1,600 ppmw, 1,500 ppmw, 1,200 ppmw, 1,000 ppmw, 500 ppmw, or 200 ppmw of polymer.

[0023] The overhead streams 118, 128, and 138 from each separation drum 110, 120, and 130 contain VOCs separated from the polymer. Each overhead stream 118, 128, and 138 can be reused and / or recycled in the polymerization process. For example, the first overhead stream 118 from the first flash drum 110 can be sent to a solvent drum (not shown) and recycled for use in the polymerization system. The second overhead stream 128 from the second flash drum 120 can be sent to a heavy column (not shown) for further separation and recycled for use in the polymerization system. The third overhead stream 138 from the third flash drum 130 can be sent to a separation column (not shown) for further separation and recycled for use in the polymerization system. The devolatilized polymer stream 134 from the third flash drum 130 is then cooled and pelletized.

[0024] 2 shows an enlarged schematic view of an exemplary vacuum flash drum that can be used as the third flash drum 130 shown in FIG. 1 according to one or more embodiments provided herein. Flash drum 130 includes a housing 210, a polymer inlet 215, a polymer outlet 225, and a volatiles outlet 235. Volatiles that evaporate from the polymer are released from housing 210 through volatiles outlet 235. A collection system, such as a condensation system (not shown), can also be connected to volatiles outlet 235 to collect the volatiles for disposal, recycling, and / or recirculation. Polymer outlet 225 contains the devolatilized polymer and directs the polymer to other downstream processes, such as a pelletizer, extruder, or other handling system.

[0025] Although not shown, housing 210 provides the desired temperature and pressure environment for devolatilizing the polymer within flash drum 130. A pressure control valve is connected to volatiles outlet 235 to control the pressure within flash drum 130. External and / or internal heat exchangers are used to maintain the desired temperature within separator 130. The heat exchange fluid may be a high-pressure steam or heated oil (e.g., a hydrocarbon such as mineral oil), or a synthetic medium. Housing 210 may contain a resistive heating element (also not shown) to control the temperature. The housing 210 may contain one or more devolatilization plates (three plates are shown as 260, 262, and 264). Each devolatilization plate 260, 262, and 264 contains a plurality of holes or apertures (not shown) formed therethrough that allow fluid communication between the plates within the housing 210. The distance between each of the devolatilization plates 260, 262, and 264 may be the same or may vary. The devolatilization plates allow and provide additional residence time and polymer solution surface renewal for enhanced mass transfer of volatiles from the polymer relative to a case without plates. The residence time on each devolatilization plate 260, 262, and 264 may vary and may be from about 5 seconds to 10 minutes, or from 10 seconds to 5 minutes. Residence times may range from a minimum of about 5 seconds, 10 seconds, or 30 seconds to a maximum of about 1 minute, 5 minutes, or 10 minutes. Additional design and operational details of suitable devolatilization plates can be found in U.S. Publication No. 2021 / 0221925.

[0026] FIG. 3 shows an enlarged schematic view of a polymer solution feed assembly 300 for entering the flash drum 130 shown in FIG. 2 , according to one or more embodiments provided herein. The polymer solution feed assembly 300 contains the solvent and unconverted monomers that remain entrained in the polymer melt. The feed assembly 300 may contain a control valve 305 and a length of piping or other conduit 310 downstream of the control valve 305. The downstream separator conduit 310 connects the control valve 305 at one end 312 (the “first end”) and projects into the drum housing 210 at its opposite end 314 (the “second end”), as shown in FIG. 2 . The downstream conduit 310 defines a feed chamber 325 for feeding or otherwise delivering the polymer solution into the flash drum 130.

[0027] The downstream conduit 310, and therefore the feed chamber 325 therein, may have any suitable shape and size. For example, the cross-section of the downstream conduit 310 and feed chamber 325 can resemble any shape, such as a circle, oval, ellipse, square, rectangle, or other polygonal shape. The inner diameter of the downstream conduit 310 at pilot plant scale can range from 5 mm, 10 mm, or 15 mm to 30 mm, 35 mm, or 40 mm. The length of the downstream conduit 310 can range from 5 cm to 50 cm. The inner diameter of the downstream conduit 310 may be constant from one end 312 to the other end 314. In certain embodiments, the inner diameter of the downstream conduit 310 may vary at one or more locations throughout its length, thereby providing one or more varying chokes within the chamber 325.

[0028] 2 and 3, the polymer solution (vapor 215) entering the drum 130 has a higher pressure before reaching pressure control valve 305, where its pressure is reduced. The pressure drop across valve 305 can range from a minimum of about 50 psig (2586 Torr), 100 psig (5,171 Torr), or 150 psig (7,757 Torr) to a maximum of about 200 psig (10,343 Torr), 300 psig (15,515 Torr), or 400 psig (20,686 Torr). The drum 130 is maintained at a vacuum pressure (i.e., less than 0 psig) using a vacuum system (not shown). The downstream conduit 310 after control valve 305 carries the polymer solution to the drum 130 and will also have a vacuum pressure since there is minimal pressure drop along the open end 314 of conduit 310. Due to this pressure differential, the volatile material will vaporize as it passes through control valve 305, thereby creating a two-phase fluid, i.e., liquid polymer and vapor volatile material, in chamber 325 of conduit 310. This significant pressure drop across valve 305 results in nucleation and foaming in chamber 325, which has open fluid communication and further feeds into drum 130.

[0029] To create the foam, the vaporized volatiles must contact the liquid polymer in chamber 325 for a predetermined length of time, or residence time, before being released into drum 130. This residence time is a function of the volumetric flow rate of the polymer solution and the length and diameter of conduit 310. Suitable residence times can range from a minimum of about 0.2, 0.4, or 0.6 seconds to a maximum of 10, 15, or 20 seconds under vacuum Devol conditions. Devolatilizer temperatures can range from 130°C to 210°C, and pressures can be less than 100 Torr, 90 Torr, 80 Torr, or 70 Torr. A foaming agent is not required or desired. Up to 3% by weight of one or more stripping agents (light gases) can be added to the polymer solution to improve VOC removal. Suitable stripping agents include C2-C5 olefins, C2-C5 alkanes, steam, carbon dioxide, or any combination thereof.

[0030] As mentioned above, the volume and diameter of conduit 310 are important design parameters for inducing foaming at the correct process conditions. This means that for a particular diameter of conduit 310, the length of conduit 310 can be adjusted to define the volume of chamber 325, or vice versa. It is also important to provide sufficient shear rate between the vapor and liquid within chamber 325 of conduit 310. This shear rate is a function of the volumetric flow rate of the polymer solution and the diameter of conduit 310. Suitable shear rates for the low viscosity polymers described herein can range from 2,000 to 200,000 1 / sec at vacuum stage conditions. 4 shows an enlarged schematic view of an alternative polymer solution feed assembly 400 for entering the flash drum 130 shown in FIG. 2 , according to one or more embodiments provided herein. This alternative polymer solution feed assembly 400 is similar to feed assembly 300 of FIG. 3 , except that its second end 414 opens to the interior of the drum housing 210. The second end 414 of assembly 400 has a reduced inner diameter (“D”) 420 to restrict fluid flow therethrough, thereby increasing the pressure drop from assembly 400 to flash drum 130. Diameter 420 can range from a minimum of about 0.5 mm, 1.0 mm, or 1.25 mm to a maximum of about 1.5 mm, 2.0 mm, or 2.5 mm.

[0031] FIG. 5 shows a schematic diagram of a vacuum flash drum 130 that can be configured to utilize multiple feed assemblies 300, 400 according to one or more embodiments provided herein. In such an embodiment, any number of feed assemblies 300, 400 can be used, either individually or in combination with one another. The various feed assemblies 300, 400 can be positioned anywhere along the sidewall 510 or at the head 520 of the drum 130. In FIG. 5, the top or upper feed assembly is shown as type 300 feed assembly and the bottom or lower feed assembly is shown as type 400 feed assembly, but any number and configuration of assemblies 300, 400 can be used. For example, the flash drum 130 can be configured with one or more feed assemblies 300 and one or more feed assemblies 400 such that the polymer feed stream 215 is split or otherwise divided to provide feed material into the flash drum 130 through either or more of the feed assemblies 300 and / or 400. The flash drum 130 can also be configured with two or more feed assemblies 300 and / or two or more feed assemblies 400 such that the polymer feed stream 215 can be split for feeding into the flash drum 130 through any combination of two or more feed assemblies 300 and / or two or more feed assemblies 400. As mentioned above, when two or more assemblies 300, 400 are used, each assembly can be of the same type (300 or 400) or a combination of types (300 and 400), and the assemblies can be arranged anywhere along the sidewall 510 or at the top head 520 of the drum 130.

[0032] The number and location of the types of feed assemblies 300, 400 can be determined by the polymer itself. For example, polymers with a Brookfield viscosity of less than 40,000 cP would prefer the feed assembly 300, and polymers with a Brookfield viscosity of 40,000 cP or greater would prefer the feed assembly 400. Having full production capability means the ability to make different polymer types and different polymer grades using the same Devol unit, and the types of assemblies 300, 400 can be easily interchanged or replaced. The system and method for devolatilizing low-viscosity polymers according to one or more embodiments provided herein can be used in any liquid-phase polymerization process. Solution polymerization processes are preferred. Suitable solution polymerization processes are generally described in more detail in U.S. Pat. Nos. 9,359,535, 7,470,118, 7,226,553, and 7,033,152, which are incorporated herein by reference in their entireties. WO 2017 / 058385A1 describes a solution polymerization process using a single or multiple spiral heat exchanger system for the continuous polymerization of C2-C40 olefins, which can also be used and is also incorporated herein by reference in its entirety.

[0033] The polymerization process can be carried out under conditions including 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 350 psi to about 1800 psi (about 2,413 to about 12,411 kPa), preferably 200 psi to 1000 psi (about 1379 kPa to 6895 kPa), preferably 300 psi to 600 psi (about 2068 kPa to 4137 kPa). Preferably, the pressure is about 450 psi (about 3103 kPa). Hydrogen may be present during the polymerization process at a partial pressure of from 0.001 psig to 50 psig (0.007 kPa to 345 kPa), preferably from 0.01 psig to 25 psig (0.07 kPa to 172 kPa), preferably from 0.1 psig to 10 psig (0.7 kPa to 70 kPa).

[0034] Suitable catalyst systems for use with the methods and systems provided herein include one or more metallocene catalysts and other single-site catalysts. Other suitable catalysts include, but are not limited to, Ziegler-Natta catalyst compounds, late transition metal catalyst compounds, and other nonmetallocene catalyst compounds. Nonmetallocene metal-centered heteroaryl ligand catalyst compounds are described in detail in PCT Patent Publication Nos. WO 02 / 38628, WO 03 / 040095 (pages 21-51), WO 03 / 040201 (pages 31-65), WO 03 / 040233 (pages 23-52), WO 03 / 040442 (pages 21-54), WO 2006 / 38628, and U.S. Patent Application Publication No. 2008 / 0153997, each of which is incorporated herein by reference.

[0035] As mentioned above, the low-viscosity polymer may be an elastomer, plastomer, thermoplastic, thermoplastic elastomer, or other type of elastomeric polymer. The low-viscosity polymer may also be a polyolefin, such as polypropylene, propylene-based polyolefin, polyethylene, ethylene-based polyolefin, polystyrene, or a combination thereof. Preferred polyolefins are copolymers or terpolymers with dienes or other polar comonomers, including silane-modified polyethylene, ethylene vinyl acetate, ethylene acrylate, and organic acid-modified polyethylene. The low-viscosity polymer may be propylene-rich (>50% by weight C3) or ethylene-rich (>50% by weight), with comonomer units derived from ethylene or higher alpha olefins from C4 to C40 inserted in a random or block-like mode.

[0036] In one or more embodiments, the low viscosity polymer can be derived from any monomer having one or more non-conjugated aliphatic double bonds and two or more carbon atoms. Exemplary monomers include substituted or unsubstituted C2-C 40 Alpha olefins are included. For example, suitable monomers can include, but are not limited to, one or more α-olefins (e.g., ethylene, propylene, butene-1, hexene-1, octene-1, decene-1, and dodecene-1), substituted olefins (e.g., styrene, paramethylstyrene, and vinylcyclohexane), non-conjugated dienes (e.g., vinylcyclohexene), α,ω-dienes (e.g., 1,5-hexadiene and 1,7-octadiene), cycloolefins (e.g., cyclopentene, cyclohexene, and cyclohexadiene), norbornene, and the like, and any combination thereof. Additional monomers include 4-methylpentene-1,3-methylpentene-1,3,5,5-trimethylhexene-1, and 5-ethylnonene-1.

[0037] Aromatic-containing monomers containing up to 30 carbon atoms can be used. Suitable aromatic-group-containing monomers have at least one aromatic structure, preferably 1 to 3, more preferably a phenyl, indenyl, fluorenyl, or naphthyl moiety. The aromatic-group-containing monomer further comprises at least one polymerizable double bond so that after polymerization, the aromatic structure is pendant from the polymer backbone. The aromatic-group-containing monomer further comprises a C1-C 10 The aromatic group may be substituted with one or more hydrocarbyl groups, including, but not limited to, alkyl groups. Furthermore, two adjacent substituents may be joined to form a ring structure. Advantageous aromatic-group-containing monomers contain at least one aromatic structure attached to a polymerizable olefin moiety. Particularly advantageous aromatic monomers include styrene, alpha-methylstyrene, para-alkylstyrene, vinyltoluene, vinylnaphthalene, allylbenzene, and indene, especially styrene, para-methylstyrene, 4-phenyl-butene-1, and allylbenzene.

[0038] Non-aromatic cyclic group-containing monomers can be used. These monomers may contain up to 30 carbon atoms. Suitable non-aromatic cyclic group-containing monomers advantageously have at least one polymerizable olefin group that is pendant to or part of the cyclic structure. The cyclic structure may be C1-C 10 It may be further substituted with one or more hydrocarbyl groups, such as, but not limited to, alkyl groups. Advantageous non-aromatic cyclic group-containing monomers include vinylcyclohexane, vinylcyclohexene, vinylnorbornene, ethylidenenorbornene, cyclopentadiene, cyclopentene, cyclohexene, cyclobutene, vinyladamantane, and the like.

[0039] Diolefin monomers can also be used. Advantageous diolefin monomers include any hydrocarbon structure, advantageously C4-C 30and having at least two unsaturated bonds, at least two of which are readily incorporated into the polymer by either stereospecific or non-stereospecific catalysis. More advantageously, the diolefin monomer is selected from alpha-omega diene monomers (e.g., divinylic monomers). More advantageously, the diolefin monomer is a linear divinylic monomer, most advantageously one containing from 4 to 30 carbon atoms. Examples of such dienes include butadiene, pentadiene, hexadiene, heptadiene, octadiene, nonadiene, decadiene, undecadiene, dodecadiene, tridecadiene, tetradecadiene, pentadecadiene, hexadecadiene, heptadecadiene, octadecadiene, nonadecadiene, icosadiene, henicosadiene, docosadiene, tricosadiene, tetracosadiene, pentacosadiene, hexadiene, and tetradecadiene. 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 (weight average molecular weight less than 1000 g / mol). Preferred cyclic dienes include cyclopentadiene, vinylnorbornene, norbornadiene, ethylidenenorbornene, divinylbenzene, dicyclopentadiene, or higher ring-containing diolefins with or without substituents at various ring positions.

[0040] In one or more embodiments, the low-viscosity polymer is a propylene-based elastomer containing greater than 50 wt.%, preferably greater than 60 wt.%, more preferably greater than 65 wt.%, even more preferably greater than 75 wt.%, and up to 99 wt.% propylene-derived units, based on the total weight of the polymer. In some preferred embodiments, the propylene-based elastomer comprises 75 wt.% to 95 wt.%, more preferably 75 wt.% to 92.5 wt.%, even more preferably 82.5 wt.% to 92.5 wt.%, and most preferably 82.5 wt.% to 90 wt.%, based on the weight of the propylene-based elastomer. Correspondingly, units derived from at least one of ethylene or a C4-C10 α-olefin, or comonomer, can be present in an amount of 5, 10, or 14 wt.% to 22 or 25 wt.% of the elastomer by weight. The comonomer content determines whether the propylene-based elastomer has a heat of fusion of 100 J / g, 90 J / g, 85 J / g, 80 J / g, 75 J / g, 70 J / g, or 65 J / g or less, a melting point (T m ), and may have a crystallinity of 2% to 65% of isotactic polypropylene.

[0041] In one or more embodiments, the low-viscosity polymer is an ethylene-based elastomer containing greater than 50 wt.%, preferably greater than 60 wt.%, more preferably greater than 65 wt.%, even more preferably greater than 75 wt.%, and up to 99 wt.%, ethylene-derived units, based on the total weight of the polymer. In some preferred embodiments, the ethylene-based elastomer has 75 wt.% to 95 wt.%, more preferably 75 wt.% to 92.5 wt.%, even more preferably 82.5 wt.% to 92.5 wt.%, and most preferably 82.5 wt.% to 90 wt.%, ethylene-derived units, based on the total weight of the polymer. Correspondingly, units or comonomers derived from C3-C10 α-olefins can be present in an amount ranging from as little as 5, 10, or 15 wt.% to as much as about 20, 25, or 30 wt.% of the polymer.

[0042] The low-viscosity polymers may be branched or unbranched, as determined by the g' average from a GPC-4D measurement. A typical GPC-4D profile has Log M vs. g', which is used to estimate the g' average based on the average across molecular weights. The branching index g' average value ranges from 1 to 0, with 1 being linear (unbranched) and 0 being fully branched. In one or more embodiments, the low-viscosity polymers may have a g' less than 0.99, less than 0.98, less than 0.97, less than 0.96, less than 0.95, or less than 0.90.

[0043] In certain embodiments, an inert solvent can be used during the polymerization process. The solvent will form part of the reactor effluent. Examples of inert solvents include linear, branched, cyclic, alicyclic, halogenated, or aromatic hydrocarbons, and mixtures thereof. Examples of linear and branched hydrocarbons include isobutane, butane, pentane, isopentane, hexane, isohexane, heptane, octane, dodecane, and mixtures thereof. Examples of cyclic and alicyclic hydrocarbons include cyclohexane, cycloheptane, methylcyclohexane, methylcycloheptane, and mixtures thereof. Examples of halogenated hydrocarbons include fluorinated C4-C10 alkanes and chlorobenzene. Examples of aromatic compounds include benzene, toluene, mesitylene, and xylene.

[0044] Additional Embodiments Other embodiments provided herein include any one or more of the following numbered embodiments: Embodiment 1: 1. A method for devolatilizing a low viscosity polymer, comprising: providing a reaction mixture comprising a polymer and one or more volatile materials, the one or more volatile materials comprising one or more unreacted monomers and at least one hydrocarbon solvent; separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase into a vapor hydrocarbon phase and a concentrated polymer phase in a second separator; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds in a separator conduit positioned between the second separator and the third separator.

[0045] Embodiment 2: The process according to embodiment 1, wherein the polymer comprises propylene and up to 20% by weight of ethylene, and / or one or more monomers having 4 or more carbon atoms. Embodiment 3: The polymer was heated at 190°C for 0.1 seconds. -1 3. The method according to claim 1 or 2, wherein the composition has a Brookfield viscosity of 300 cP to 40,000 cP or a zero shear viscosity of less than 200 Pa·sec, when measured at a frequency of 1000 kJ / s. Embodiment 4: The process according to any of embodiments 1-3, wherein the polymer has a weight average molecular weight (Mw) of less than 62,000 g / mol as determined by GPC, or a melt flow rate (MFR) of 500 to 40,000 g / 10 min as measured by ASTM D1238.

[0046] Embodiment 5: The process according to any one of embodiments 1 to 4, wherein the concentrated polymer phase has a volatiles concentration of 4 to 15 wt. %, based on the total weight of the concentrated polymer phase. Embodiment 6: The method according to any one of embodiments 1 to 5, wherein the separator conduit is configured to provide a shear rate of 2,000 to 200,000 1 / sec. Embodiment 7: The process according to any one of embodiments 1 to 6, wherein the devolatilized polymer has a volatiles concentration of less than 600 ppmw based on the total weight of the concentrated polymer phase.

[0047] Embodiment 8: 1. A method for devolatilizing a low viscosity polymer, comprising: providing a reaction mixture comprising a polymer having a Brookfield viscosity of less than 40,000 cP and a weight average molecular weight (Mw) of less than 62,000 g / mol as determined by GPC; and one or more volatile materials, the one or more volatile materials comprising one or more unreacted monomers and at least one hydrocarbon solvent; separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase into a vapor hydrocarbon phase and a concentrated polymer phase in a second separator; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds in a separator conduit positioned between the second separator and the third separator. Embodiment 9: The process according to embodiment 8, wherein the polymer comprises propylene and up to 20% by weight of ethylene, and / or one or more monomers having 4 or more carbon atoms.

[0048] Embodiment 10: 10. The method of claim 8 or 9, wherein the polymer has a Brookfield viscosity of less than 15,000 cP. Embodiment 11: The process according to any one of embodiments 8 to 10, wherein the concentrated polymer phase has a volatiles concentration of 4 to 15 wt. %, based on the total weight of the concentrated polymer phase. Embodiment 12: The method according to any one of embodiments 8 to 11, wherein the separator conduit is configured to provide a shear rate of 2,000 to 200,000 1 / sec at the third separator condition.

[0049] Embodiment 13: The process according to any one of embodiments 8 to 12, wherein the devolatilized polymer has a volatiles concentration of less than 600 ppmw based on the total weight of the concentrated polymer phase. Embodiment 14: 1. A method for devolatilizing a low viscosity polymer, comprising: providing a reaction mixture comprising a polymer having a Brookfield viscosity of less than 40,000 cP, a weight average molecular weight (Mw) of less than 62,000 g / mol as determined by GPC, and an MFR (ASTM D1238) of 500 to 40,000 g / 10 min; and one or more volatile materials, the one or more volatile materials comprising one or more unreacted monomers and at least one hydrocarbon solvent; separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase into a vapor hydrocarbon phase and a concentrated polymer phase in a second separator; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds at third separator conditions in a separator conduit positioned between the second separator and the third separator.

[0050] Embodiment 15: 15. The method of embodiment 14, wherein the separator conduit is configured to provide a shear rate at the third separator condition of from 2,000 to 200,000 1 / sec. Embodiment 16: 16. The process according to embodiment 14 or 15, wherein the devolatilized polymer has a volatiles concentration of less than 600 ppmw based on the total weight of the concentrated polymer phase. Embodiment 17: The process according to any one of embodiments 14 to 16, wherein the polymer is 85 to 99% by weight of units derived from propylene and 1 to 15% by weight of units derived from ethylene. Embodiment 18: The polymer was heated at 190°C for 0.1 seconds. -1 18. The method according to any one of embodiments 14 to 17, wherein the composition has a zero shear viscosity of less than 200 Pa·sec when measured at a frequency of 1000 Pa·sec.

[0051] Embodiment 19: The method according to any one of embodiments 14 to 18, wherein the polymer has a weight average molecular weight (Mw) of less than 46,000 g / mol. Embodiment 20: 1. A system for devolatilizing low viscosity polymers, comprising: a first separator for separating a reaction mixture comprising a polymer and one or more volatile materials into a polymer-rich phase and a polymer-lean phase, the one or more volatile materials comprising one or more unreacted monomers and at least one hydrocarbon solvent; a second separator for separating the polymer-rich phase into a vapor hydrocarbon phase and a concentrated polymer phase; a third separator for removing at least a portion of the volatile materials from the concentrated polymer phase; and a separator conduit positioned between the second and third separators, the separator conduit configured to provide a residence time therein of about 0.2 seconds to 10 seconds. [Example]

[0052] The foregoing discussion can be further described with reference to the following non-limiting examples. Three low viscosity polymers, ranging in viscosity from 1,100 to 11,500 cP, were devolatilized in a vacuum flash vessel. The inlet polymer solution feed had a volatiles concentration of 4 to 10 wt. % in three cases. The polymers were propylene-ethylene elastomers ("PBE") obtained from ExxonMobil Product Solutions Company. All three polymers had an ethylene content of 6 wt. % with the remainder being propylene and are summarized in Table 1 below. Table 1: Physical properties of the three PBEs are summarized below: [Table 1]

[0053] A range of temperatures and vacuum pressures was tested in each case. Devolatilization pressures ranged from 20 to 100 Torr, and temperatures ranged from 135 to 165°C. Two polymer inlet feed configurations were used. The first configuration was an open-ended conduit feed assembly 300, and the second was a choke conduit feed assembly 400. In the first open-ended configuration, the pressure in the conduit section downstream of the control valve equaled the flash drum pressure, and two phases (liquid and vapor) were observed in the conduit chamber. In the second choke configuration, the pressure in the conduit section downstream of the control valve was higher than the drum pressure and higher than the vapor pressure of the polymer solution. Only a single liquid phase was observed in the inlet piping chamber, so that any evaporation of volatiles occurred after the solution left the choke section and entered the flash drum. The results are reported in Tables 2 and 3 below.

[0054] Table 2: Process conditions and results for polymer devolatilization using open-ended feed configuration 300. [Table 2]

[0055] Table 3: Process conditions and results for polymer devolatilization using choke feed configuration 400. [Table 3]

[0056] Figure 6 graphically illustrates the VOC HSGC values ​​obtained from the two inlet feed configurations plotted against the equilibrium HSGC values. This shows the measured VOC along with the calculated equilibrium VOC for the range of process operating windows tested (i.e., 20-100 Torr and 135-165°C). This HSGC data demonstrates the positive effect of foaming and approaching equilibrium VOC to reduce the VOC content of the polymer. As shown in Figure 6, polymers devolatilized using the open-ended inlet piping configuration resulted in foaming and a polymer with a VOC at or near the equilibrium VOC. In contrast, the same polymers devolatilized using the choke-type inlet piping configuration resulted in significantly higher amounts of VOC in the polymer. Based on this data, and without being bound by theory, it appears surprisingly and unexpectedly that foam nucleation and foam intensity were not only a function of initial volatile concentration, temperature, and pressure (degree of superheat), but also a function of shear rate and residence time (i.e., volatile-polymer exposure time) within the feed conduit chamber 325.

[0057] Test Procedure In the foregoing examples, the following test methods and procedures were used: Headspace gas chromatography (HSGC) was used to measure the volatile content of polymer pellets. In this method, 2 g of pellets were placed in a 20 ml vial. The vial was heated at 130°C for 35 minutes. The headspace of the vial was then injected into the GC. The shear rate in the conduit 310 is calculated using the Hagen-Poiseuille equation: shear rate (1 / sec) = 4Q / πr 3 where Q is the polymer solution volumetric flow rate at vacuum Devol conditions and r is the radius of the piping. "Vacuum Devol conditions" means the same temperature and pressure as inside the third and / or final flash drum 130.

[0058] Brookfield viscosity was measured at 190°C. The spindle was rotated at 20 rpm, and data was collected every 30 seconds at 15-minute intervals. Torque was maintained at a level of 45-55% throughout the test. MFR was measured according to (ASTM D1238). For low viscosities that are difficult to measure, MFR can be calculated according to the relationship: MFR(ASTM D1238)=9591437×BV -0.93 , (R 2 =0.99), where BV is Brookfield viscosity.

[0059] Molecular weight distributions and moments (Mw, Mn, Mz, Mw / Mn, Mz / Mn, etc.) and comonomer contents (C2, C4, C8) were determined using high-temperature gel permeation chromatography (Polymer Char GPC-IR) equipped with a multichannel band filter-based infrared detector IR5, an 18-angle light scattering detector, and a viscometer. Three Agilent Plgel 10 μm mixed-type-B LS columns were used to perform polymer separation. Detailed analytical principles and methods for molecular weight determination are described in paragraphs

[0044] to

[0051] of International Publication No. WO / 2019 / 246069A1, which is incorporated herein by reference. (Note that the equation for c, referred to in paragraph

[0044] within the paragraph

[0044] in relation to the concentration I at each point in the chromatogram, is c = βI, where β is the mass constant and I is the baseline-subtracted IR5 broadband signal intensity (I).) Unless otherwise specified, all molecular weight moments used or referred to in this disclosure are determined according to conventional molecular weight (IR molecular weight) determination methods (see, for example, paragraphs

[0044] to

[0045] of the just-mentioned publication), and it should be noted that for the equation in such paragraph

[0044] , a = 0.695 and K = 0.000579 (1 - 0.75Wt) are used, where Wt is the mass fraction of hexane comonomer, and further that the comonomer composition is determined by the ratio of the IR detector intensities corresponding to the CH2 and CH3 channels (providing methyls per 1000 total carbon atoms (CH3 / 1000TC) as described in paragraph

[0045] of the just-mentioned international publication) calibrated with a series of PE and PP homo / copolymer standards whose nominal values ​​have been previously determined by NMR or FTIR.

[0060] All numerical values ​​are designated "about" or "approximately" and take into account experimental error and deviation that can be expected by one of ordinary skill in the art. Numerous variations, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description without departing from the spirit or scope of the present disclosure, and when lower numerical limits and upper numerical ratio limits are recited herein, ranges from any lower limit to any upper limit are contemplated.

[0061] 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 of ordinary skill in the art can give that term as reflected in at least one printed reference 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 such disclosure is not inconsistent with this application, and are incorporated for all jurisdictions where such incorporation is permitted.

[0062] 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, which scope is determined by the following claims.

Claims

1. 1. A method for devolatilizing a low viscosity polymer, comprising: providing a reaction mixture comprising a polymer and one or more volatile materials, the one or more volatile materials comprising one or more unreacted monomers and at least one hydrocarbon solvent; separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase in a second separator into a vaporous hydrocarbon phase and a concentrated polymer phase; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds in a separator conduit positioned between the second separator and the third separator; A method comprising:

2. 10. The method of claim 1, wherein the polymer comprises propylene and up to 20% by weight of ethylene, and / or one or more monomers having 4 or more carbon atoms.

3. The polymer is heated at 190° C. for 0.1 seconds. -1 10. The method of claim 1, wherein the composition has a Brookfield viscosity of 300 cP to 40,000 cP or a zero shear viscosity of less than 200 Pa-sec when measured at a frequency of 1000 kJ / s.

4. 10. The method of claim 1, wherein the polymer has a weight average molecular weight (Mw) of less than 62,000 g / mol as determined by GPC, or a melt flow rate (MFR) of 500 to 40,000 g / 10 min as measured by ASTM D1238.

5. 10. The method of claim 1, wherein the concentrated polymer phase has a volatiles concentration of 4 to 15% by weight, based on the total weight of the concentrated polymer phase.

6. The method of claim 1 , wherein the separator conduit is configured to provide a shear rate of 2,000 to 200,000 1 / sec.

7. 10. The method of claim 1, wherein the devolatilized polymer has a volatiles concentration of less than 600 ppmw based on the total weight of the concentrated polymer phase.

8. 1. A method for devolatilizing a low viscosity polymer, comprising: providing a reaction mixture comprising a polymer having a Brookfield viscosity of less than 40,000 cP and a weight average molecular weight (Mw) of less than 62,000 g / mol as determined by GPC, and one or more volatile materials, wherein the one or more volatile materials comprise one or more unreacted monomers and at least one hydrocarbon solvent; separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase in a second separator into a vaporous hydrocarbon phase and a concentrated polymer phase; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds in a separator conduit positioned between the second separator and the third separator; A method comprising:

9. 9. The method of claim 8, wherein the polymer comprises propylene and up to 20% by weight of ethylene, and / or one or more monomers having 4 or more carbon atoms.

10. 9. The method of claim 8, wherein the polymer has a Brookfield viscosity of less than 15,000 cP.

11. 9. The method of claim 8, wherein the concentrated polymer phase has a volatiles concentration of 4 to 15% by weight, based on the total weight of the concentrated polymer phase.

12. 9. The method of claim 8, wherein the separator conduit is configured to provide a shear rate at the third separator condition of from 2,000 to 200,000 1 / sec.

13. 9. The method of claim 8, wherein the devolatilized polymer has a volatiles concentration of less than 600 ppmw based on the total weight of the concentrated polymer phase.

14. 1. A method for devolatilizing a low viscosity polymer, comprising: a polymer having a Brookfield viscosity of less than 40,000 cP, a weight average molecular weight (Mw) of less than 62,000 g / mol as determined by GPC, and an MFR (ASTM D1238) of 500 to 40,000 g / 10 min; one or more volatile materials including one or more unreacted monomers and at least one hydrocarbon solvent; providing a reaction mixture comprising: separating the reaction mixture into a polymer-rich phase and a polymer-lean phase in a first separator; separating the polymer-rich phase in a second separator into a vaporous hydrocarbon phase and a concentrated polymer phase; removing at least a portion of the volatile materials from the concentrated polymer phase in a third separator to provide a devolatilized polymer; and providing a residence time of about 0.2 seconds to 10 seconds at third separator conditions in a separator conduit located between said second separator and said third separator; A method comprising:

15. 15. The method of claim 14, wherein the separator conduit is configured to provide a shear rate of 2,000 to 200,000 1 / sec at the third separator condition.

16. 16. The method of claim 15, wherein the devolatilized polymer has a volatiles concentration of less than 600 ppmw based on the total weight of the concentrated polymer phase.

17. 16. The method of claim 15, wherein the polymer is 85 to 99 weight percent propylene-derived units and 1 to 15 weight percent ethylene-derived units.

18. The polymer is heated at 190° C. for 0.1 seconds. -1 16. The method of claim 15, wherein the composition has a zero shear viscosity of less than 200 Pa-sec when measured at a frequency of 0.15 Pa.s.

19. 16. The method of claim 15, wherein the polymer has a weight average molecular weight (Mw) of less than 46,000 g / mol.

20. a first separator for separating a reaction mixture comprising a polymer and one or more volatile materials into a polymer-rich phase and a polymer-lean phase, the one or more volatile materials comprising one or more unreacted monomers and at least one hydrocarbon solvent; a second separator for separating the polymer-rich phase into a vaporous hydrocarbon phase and a concentrated polymer phase; a third separator for removing at least a portion of the volatile materials from the concentrated polymer phase; and a separator conduit positioned between the second separator and the third separator, the separator conduit configured to provide a residence time therein of about 0.2 seconds to 10 seconds; 1. A system for devolatilizing low viscosity polymers, comprising:

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