WO2025072152A1

WO2025072152A1 - Process for the production of ldpe

Info

Publication number: WO2025072152A1
Application number: PCT/US2024/048139
Authority: WO
Inventors: Nhi T. Y. Dang; Jonathan D. MENDENHALL; Arkady L. Krasovskiy; Sean W. Ewart
Original assignee: Dow Global Technologies LLC
Current assignee: Dow Global Technologies LLC
Priority date: 2023-09-29
Filing date: 2024-09-24
Publication date: 2025-04-03
Anticipated expiration: 2026-03-29

Abstract

A process for producing low-density polyethylene (LDPE) comprises feeding ethylene into a front inlet and one or more side inlets of the high-pressure reactor; and feeding a mixture of hydrocarbon-based molecules into the high-pressure reactor, each hydrocarbon-based molecule comprising three or more carbon-carbon double bonds. At least 20 wt. % of a total amount of ethylene fed to the high-pressure reactor may be fed to the front inlet of the high-pressure reactor; at least 20 wt. % of the total amount of ethylene fed to the high-pressure reactor may be fed to a first side inlet of the high-pressure reactor; at least 40 wt. % of the mixture of hydrocarbon-based molecules may be fed to the front inlet of the high-pressure reactor; and the mixture of hydrocarbon-based molecules may be fed to the high-pressure reactor downstream of at least one hyper-compressor, thereby producing the LDPE via free radical polymerization.

Description

PROCESS FOR THE PRODUCTION OF EDPE

CROSS-REFERENCE TO REEATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63/586,470 filed September 29, 2023, the contents of which are incorporated in their entirety herein.

TECHNICAL FIELD

[0002] Embodiments of the present disclosure relate to processes for the production of ethylenebased polymers, and more specifically, to the production of low-density polyethylene.

BACKGROUND

[0003] High-pressure tubular reactors have been used in industry for making low density polyethylene (LDPE) products for over 40 years. The plug-flow characteristics of a tubular reactor create gradients of temperature, pressure, and polymer/ ethylene concentration along the reactor. Therefore, LDPE materials made with tubular reactors typically have narrower molecular weight distribution (“Mw/Mn”) and lower melt strength (“MS”) than conventionally produced LDPE. This limits the suitability of LDPE produced in tubular reactors certain applications, such as extrusion coatings and blown fdms.

[0004] Known methods of altering the Mw/Mn and MS of LDPE materials include modifying reactor configurations, fine-tuning process conditions (pressure and temperature), modifying the reactor configuration, and varying modifier (such as chain transfer agent (CTA)) concentration along the reactor therefore extending the product capability of tubular reactors.

[0005] Through those efforts, materials suitable for extrusion coatings (having suitable neck-in (NI) and drawdown (DD)) have been successfully produced on tubular reactors. However, penalties on density, FDA extractables, and smoke have been observed.

[0006] One solution explored has been the use of branching agents, which can broaden the molecular weight distribution, thus increasing melt strength under less extreme process conditions. Density capability, FDA extractables and extrusion coating performance may also be improved in this manner.

[0007] However, the use of branching agents increases the raw material cost significantly. In addition, high level of unsaturated groups and un-converted branching agent can cause high gel levels in the final products, increasing the amount of off-grade product. During the extrusion coating, products with high levels of unreacted branching agent levels tend to have increased smoke, undesired taste and odor, and edge instability.

BRIEF SUMMARY

[0008] There is a need to reduce the concentration of branching agent required to achieve the desired molecular weight distribution, melt strength, and other polymer properties. Additionally, there is a need to reduce the quantity of unreacted branching agent in the LDPE.

[0009] Embodiments of this disclosure meet this need by providing a process, which feeds the majority of the branching agent to the front of the reactor. It has surprisingly been discovered that, for a given branching agent concentration, introducing the majority (or even all) of the branching agent to the front of the reactor produces polymers with improved melt strength and molecular weight distributions, relative to introducing the branching agent to the side of the reactor. Additionally, it has been found that particular configurations of fresh ethylene feed can result in improved melt strength and molecular weight distributions.

[0010] According to some embodiments, a process for producing low-density polyethylene (LDPE) may comprise feeding ethylene into a front inlet of a high-pressure reactor at a pressure of at least 1000 bar; feeding ethylene into one or more side inlets of the high-pressure reactor at a pressure of at least 1000 bar; and feeding a mixture of hydrocarbon-based molecules into the high- pressure reactor, each hydrocarbon-based molecule comprising three or more carbon-carbon double bonds. At least 20 wt. % of a total amount of ethylene fed to the high-pressure reactor may be fed to the front inlet of the high-pressure reactor; at least 20 wt. % of the total amount of ethylene fed to the high-pressure reactor may be fed to a first side inlet of the high-pressure reactor; at least 40 wt. % of the mixture of hydrocarbon-based molecules may be fed to the front inlet of the high-pressure reactor; and the mixture of hydrocarbon-based molecules may be fed to the high- pressure reactor downstream of at least one hyper-compressor, thereby producing the LDPE via free radical polymerization at a pressure of at least 1000 bar.

[0011] These and other embodiments are described in more detail in the Detailed Description. It is to be understood that both the foregoing general description and the following detailed description present embodiments of the presently disclosed technology, and are intended to provide an overview or framework for understanding the nature and character of the technology as it is claimed. The accompanying drawings are included to provide a further understanding of the presently disclosed technology and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments and, together with the description, serve to explain the principles and operations of the presently disclosed technology. Additionally, the drawings and descriptions are meant to be merely illustrative, and are not intended to limit the scope of the claims in any manner.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

[0013] FIG. 1 is a schematic diagram of a system for forming low-density polyethylene, in accordance with one embodiment described and disclosed herein.

[0014] FIG. 2 is a graphical illustration of the relationship between melt strength, branching agent concentration, and branching agent feed location.

[0015] FIG. 3 is a graphical illustration of the GPC results of several polymers, according to some embodiments of the present disclosure.

[0016] For the purpose of describing the simplified schematic illustrations and descriptions of the relevant figures, the numerous valves, temperature sensors, electronic controllers and the like that may be employed and well known to those of ordinary skill in the art of certain chemical processing operations are not included. Further, accompanying components that are often included in typical chemical processing operations, such as air supplies, catalyst hoppers, and flue gas handling systems, are not depicted. However, operational components, such as those described in the present disclosure, may be added to the embodiments described in this disclosure.

[0017] It should further be noted that arrows in the drawings refer to process streams. However, the arrows may equivalently refer to transfer lines which may serve to transfer process streams between two or more system components. Additionally, arrows that connect to system components define inlets or outlets in each given system component. The arrow direction corresponds generally with the major direction of movement of the materials of the stream contained within the physical transfer line signified by the arrow. Furthermore, arrows which do not connect two or more system components signify a product stream which exits the depicted system or a system inlet stream which enters the depicted system. Product streams may be further processed in accompanying chemical processing systems or may be commercialized as end products. System inlet streams may be streams transferred from accompanying chemical processing systems or may be non-processed feedstock streams. Some arrows may represent recycle streams, which are effluent streams of system components that are recycled back into the system. However, it should be understood that any represented recycle stream, in some embodiments, may be replaced by a system inlet stream of the same material, and that a portion of a recycle stream may exit the system as a system product.

[0018] Additionally, arrows in the drawings may schematically depict process steps of transporting a stream from one system component to another system component. For example, an arrow from one system component pointing to another system component may represent “passing” a system component effluent to another system component, which may include the contents of a process stream “exiting” or being “removed” from one system component and “introducing” the contents of that product stream to another system component. It should be understood that arrows in the relevant figures are not indicative of necessary or essential steps.

[0019] It should be understood that according to the embodiments presented in the relevant figures, an arrow between two system components may signify that the stream is not processed between the two system components. In other embodiments, the stream signified by the arrow may have substantially the same composition throughout its transport between the two system components. Additionally, it should be understood that in one or more embodiments, an arrow may represent that at least 75 wt.%, at least 90 wt.%, at least 95 wt.%, at least 99 wt.%, at least 99.9 wt.%, or even 100 wt.% of the stream is transported between the system components. As such, in some embodiments, less than all of the streams signified by an arrow may be transported between the system components, such as if a slip stream is present.

[0020] It should be understood that two or more process streams are “mixed” or “combined” when two or more lines intersect in the schematic flow diagrams of the relevant figures. Mixing or combining may also include mixing by directly introducing both streams into a like reactor, separation device, or other system component. For example, it should be understood that when two streams are depicted as being combined directly prior to entering a separation unit or reactor, that in some embodiments the streams could equivalently be introduced into the separation unit or reactor and be mixed in the reactor. [0021] Reference will now be made in greater detail to various embodiments, some embodiments of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts.

DETAILED DESCRIPTION

[0022] The term “polymer” refers to a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term “homopolymer,” usually employed to refer to polymers prepared from only one type of monomer as well as “copolymer” which refers to polymers prepared from two or more different monomer types.

[0023] “Polyethylene” or “ethylene-based polymer” shall mean polymers comprising greater than 50% by weight of units which have been derived from ethylene monomer. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more monomer types). Common forms of polyethylene known in the art include low-density Polyethylene (LDPE); Linear Low-Density Polyethylene (LLDPE); Ultra Low-Density Polyethylene (ULDPE); Very Low-Density Polyethylene (VLDPE); single-site catalyzed Linear Low-Density Polyethylene, including both linear and substantially linear low-Density resins (m-LLDPE); Medium Density Polyethylene (MDPE); and High Density Polyethylene (HDPE).

[0024] The term “LDPE” may also be referred to as “high-pressure ethylene polymer” or “highly branched polyethylene” and is defined to mean that the polymer is partly or entirely homopolymerized or copolymerized in autoclave or tubular reactors at pressures above 14,500 psi (100 MPa) with the use of free-radical initiators, such as peroxides (see, for example, U.S. Patent No. 4,599,392, which is hereby incorporated by reference in its entirety). LDPE resins typically have a density in the range of 0.916 g/cm³ to 0.930 g/cm³.

[0025] The term “LLDPE,” includes resin made using Ziegler-Natta catalyst systems as well as resin made using single-site catalysts, including, but not limited to, bis-metallocene catalysts (sometimes referred to as “m-LLDPE”), phosphinimine, and constrained geometry catalysts, and resins made using post-metallocene, molecular catalysts, including, but not limited to, bis(biphenylphenoxy) catalysts (also referred to as polyvalent aryloxy ether catalysts). LLDPE includes linear, substantially linear, or heterogeneous ethylene-based copolymers. LLDPEs contain less long chain branching than LDPEs and include the substantially linear ethylene polymers, which are further defined in U.S. Patent No. 5,272,236, U.S. Patent No. 5,278,272, U.S. Patent No. 5,582,923 and U.S. Patent No. 5,733,155 each of which are incorporated herein by reference in their entirety; the homogeneously branched linear ethylene polymer compositions such as those in U.S. Patent No. 3,645,992 which is incorporated herein by reference in its entirety; the heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Patent No. 4,076,698 which is incorporated herein by reference in its entirety; and blends thereof such as those disclosed in U.S. Patent No. 3,914,342 and U.S. Patent No. 5,854,045 which are incorporated herein by reference in their entirety. The LLDPE resins can be made via gas-phase, solution-phase, or slurry polymerization or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0026] The term “terminal carbon-carbon double bond,” as used herein, refers to a double bond between two carbon atoms in a polymer chain, wherein one of the carbons in the double-bond is a =CH2 group. Terminal double bonds are located at terminal ends of polymer chains and/or at branched ends of polymer chains. The term “internal carbon-carbon double bonds,” as used herein, refers to a 1,2-disubstituted carbon-carbon double bond. An internal carbon-carbon double bond is located throughout the length of a polymer chain, but not at a terminal end of the polymer chain or at a branched end along a polymer chain. Terminal carbon-carbon double bonds and internal carbon-carbon double bonds are measured by infrared spectroscopy (“IR”).

[0027] The term “alkene content,” as used herein, refers to the number of terminal carbon-carbon double bonds plus the number of internal carbon-carbon double bonds, present in a polymer chain for every 1000 carbon atoms. Alkene content is measured by infrared spectroscopy (“IR”).

[0028] The term “reaction zone,” as used herein, refers to a zone in which a polymerization reaction occurs. The beginning of a reaction zone, is defined by the side injection of initiator. The end of a reaction zone is defined by either the reactor outlet or the next side injection of initiator. For example, the first reaction zone is the space between the first injection of initiator and the second injection of initiator. The second reaction zone is the space between the second injection of initiator and the third injection of initiator. The third reaction zone is the space between the third injection of initiator and the fourth injection of initiator.

[0029] Referring now to FIG. 1, a process for producing ethylene may utilize a system 100 for producing ethylene. The system 100 may comprise one or more hyper-compressors 102, operable to compress one or more medium pressure ethylene feed streams 126 into an ethylene front stream 128 and one or more ethylene side streams 124. The ethylene front stream 128 and the one or more ethylene side streams 124 may be compressed in a single hyper-compressor 102 or in separate hyper-compressors 102. The ethylene front stream 128 may be fed to a front inlet of a high-pressure reactor 104. The one or more ethylene side streams 124 may each be fed to individual side inlets of the high-pressure reactor 104. The system 100 may comprise one or more initiator feed streams 116, 118, 120, such as a first initiator feed stream 116, a second initiator feed stream 118, and a third initiator feed stream 120. The first ethylene side stream 110 may be introduced to the high-pressure reactor 104 at a first side inlet. The first side inlet may be downstream of the first initiator feed stream 116 and upstream of a second initiator feed stream 118, if a second initiator feed stream 118 is present. If a second ethylene feed stream 112 is present, the second ethylene feed stream 112 may be introduced to the high-pressure reactor 104 at a second side inlet. The second side inlet may be downstream of the first side inlet and the first initiator feed stream 116. Initiator (e.g. the second initiator feed stream 118) may be introduced to the high-pressure reactor 104 through the second side inlet (co-fed with the second ethylene feed stream 112) or may be introduced downstream of the second side inlet.

[0030] If a third ethylene feed stream 114 is present, the third ethylene feed stream 114 may be introduced to the high-pressure reactor 104 at a third side inlet. The third side inlet may be downstream of the second side inlet and the second initiator feed stream 118. Initiator (e.g. the third initiator feed stream 120) may be introduced to the high-pressure reactor 104 through the third side inlet (co-fed with the third ethylene feed stream 114) or may be introduced downstream of the third side inlet. . It should be understood that initiator feed streams, after the first initiator feed stream, may enter the reactor through dedicated injection ports or may be combined with an ethylene side stream before introduction to the high-pressure reactor 104.

[0031] The system 100 may further comprise a hydrocarbon molecule pump 106 which pressurizes a low pressure hydrocarbon molecule feed stream 130, thereby forming a hydrocarbon molecule feed stream 108. The hydrocarbon molecule feed stream 108 may provide a fluid connection between the hydrocarbon molecule pump 106 and the high-pressure reactor 104. The hydrocarbon molecule feed stream 108 may connect directly to the high-pressure reactor 104, upstream of the first initiator feed stream 116; or the hydrocarbon molecule feed stream 108 may connect to the ethylene front stream 128 upstream of the first initiator feed stream 116. The hydrocarbon molecule feed stream 108 may connect to the ethylene front stream 128 downstream of the hyper-compressor 102. Without being limited by theory, it is believed that introducing the mixture of hydrocarbon molecules to the ethylene stream upstream of the hyper-compressor 102 may cause undesired polymerization of the ethylene, fouling the hyper-compressor 102.

[0032] A process for producing low-density polyethylene (LDPE) may comprise feeding ethylene into a front inlet of a high-pressure reactor; feeding ethylene into one or more side inlets of the high-pressure reactor; and feeding a mixture of hydrocarbon-based molecules into the high- pressure reactor. The process may further comprise feeding an initiator to the high-pressure reactor 104 between the front inlet and the first side inlet.

[0033] The process may comprise feeding the ethylene into the front inlet of a high-pressure reactor 104 at a pressure of at least 1000 bar, such as at least 1200 bar, at least 1500 bar, at least 1700 bar, at least 2000 bar, from 1000 bar to 4000 bar, from 1200 bar to 4000 bar, from 1500 bar to 4000 bar, from 1700 bar to 4000 bar, from 2000 bar to 4000 bar, from 2000 bar to 3200 bar, or any subset thereof.

[0034] At least 20 wt. % of a total amount of ethylene fed to the high-pressure reactor 104 may be fed to the front inlet of the high-pressure reactor 104. The ethylene fed to the front inlet of the high-pressure reactor 104 may be fed upstream of the first initiator feed stream 116 injection point. In embodiments, at least 25 wt. %, at least 30 wt. %, at least 40 wt. %, at least 45 wt. %, at least 50 wt. %, about 50 wt. %, from 25 wt. % to 60 wt. %, from 30 wt. % to 60 wt. %, from 40 wt. % to 60 wt. %, or any subset thereof, of the total amount of ethylene fed to the high-pressure reactor 104 may be fed to the front inlet of the high-pressure reactor 104.

[0035] The process may comprise feeding ethylene into one or more side inlets of the high- pressure reactor at a pressure of at least 1000 bar, such as at least 1200 bar, at least 1500 bar, at least 1700 bar, at least 2000 bar, from 1000 bar to 4000 bar, from 1200 bar to 4000 bar, from 1500 bar to 4000 bar, from 1700 bar to 4000 bar, from 2000 bar to 4000 bar, from 2000 bar to 3200 bar, or any subset thereof.

[0036] At least 20 wt. % of the total amount of ethylene fed to the high-pressure reactor 104 may be fed to a first side inlet of the high-pressure reactor 104. The ethylene fed to the first side inlet of the high-pressure reactor 104 may be fed downstream of the first initiator feed stream 116 injection point and if a second initiator feed stream 118 is present, upstream of the second initiator feed stream 118 injection point. In embodiments, at least 25 wt. %, at least 30 wt. %, at least 40 wt. %, at least 45 wt. %, at least 50 wt. %, about 50 wt. %, from 25 wt. % to 60 wt. %, from 30 wt. % to 60 wt. %, from 40 wt. % to 60 wt. %, or any subset thereof, of the total amount of ethylene fed to the high-pressure reactor 104 may be fed to the first side inlet of the high-pressure reactor 104.

[0037] In embodiments, all or substantially all of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet and the first side inlet. For example, at least 80 wt. %, at least 90 wt. %, at least 95 wt. %, or at least 99 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet and the first side inlet.

[0038] In embodiments where all or substantially all of the ethylene introduced to the high- pressure reactor 104 through the front inlet and the first side inlet, from 40 wt. % to 60 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet and from 40 wt. % to 60 wt. % the ethylene introduced to the high-pressure reactor 104 may be introduced through the first side inlet.

[0039] The process may further comprise feeding ethylene to a second side inlet of the high- pressure reactor 104. Such embodiments may further comprise feeding an initiator to the high- pressure reactor 104 between the first side inlet and the second side inlet, or feed an initiator to the high-pressure reactor 104 through the second side inlet.

[0040] In embodiments, all or substantially all of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet, the first side inlet, and the second side inlet. For example, at least 80 wt. %, at least 90 wt. %, at least 95 wt. %, or at least 99 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet, the first side inlet, and the second side inlet.

[0041] In embodiments where ethylene is introduced to the high-pressure reactor 104 through the front inlet, the first side inlet, and the second side inlet, from 20 wt. % to 45 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet, from 20 wt. % to 45 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the first side inlet, and from 20 wt. % to 45 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the second side inlet. From 20 wt. % to 40 wt. %, from 20 wt. % to 35 wt. %, from 25 wt. % to 45 wt. %, from 30 wt. % to 45 wt. %, from 25 wt. % to 40 wt. %, from 30 wt. % to 35 wt. %, or any subset thereof, of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet. From 20 wt. % to 40 wt. %, from 20 wt. % to 35 wt. %, from 25 wt. % to 45 wt. %, from 30 wt. % to 45 wt. %, from 25 wt. % to 40 wt. %, from 30 wt. % to 35 wt. %, or any subset thereof, of the ethylene introduced to the high-pressure reactor 104 may be introduced through the first side inlet. From 20 wt. % to 40 wt. %, from 20 wt. % to 35 wt. %, from 25 wt. % to 45 wt. %, from 30 wt. % to 45 wt. %, from 25 wt. % to 40 wt. %, from 30 wt. % to 35 wt. %, or any subset thereof, of the ethylene introduced to the high-pressure reactor 104 may be introduced through the second side inlet.

[0042] The process may further comprise feeding ethylene to a third side inlet of the high- pressure reactor 104. Such embodiments may further comprise feeding an initiator to the high- pressure reactor 104 between the second side inlet and the third side inlet, or feeding the initiator to the high-pressure reactor 104 through the third side inlet.

[0043] In embodiments, all or substantially all of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet, the first side inlet, the second side inlet, and the third side inlet. For example, at least 80 wt. %, at least 90 wt. %, at least 95 wt. %, or at least 99 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet, the first side inlet, the second side inlet, and the third side inlet.

[0044] In embodiments where ethylene is introduced to the high-pressure reactor 104 through the front inlet, the first side inlet, the second side inlet, and the third side inlet, from 20 wt. % to 45 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet, from 20 wt. % to 45 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the first side inlet, from 20 wt. % to 45 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the second side inlet, and from 20 wt. % to 45 wt. % of the ethylene introduced to the high-pressure reactor 104 may be introduced through the third side inlet.

[0045] From 20 wt. % to 40 wt. %, from 20 wt. % to 35 wt. %, from 20 wt. % to 30 wt. %, from 25 wt. % to 45 wt. %, from 30 wt. % to 45 wt. %, from 25 wt. % to 40 wt. %, from 30 wt. % to 35 wt. %, or any subset thereof, of the ethylene introduced to the high-pressure reactor 104 may be introduced through the front inlet. From 20 wt. % to 40 wt. %, from 20 wt. % to 35 wt. %, from 20 wt. % to 30 wt. %, from 25 wt. % to 45 wt. %, from 30 wt. % to 45 wt. %, from 25 wt. % to 40 wt. %, from 30 wt. % to 35 wt. %, or any subset thereof, of the ethylene introduced to the high- pressure reactor 104 may be introduced through the first side inlet. From 20 wt. % to 40 wt. %, from 20 wt. % to 35 wt. %, from 20 wt. % to 30 wt. %, from 25 wt. % to 45 wt. %, from 30 wt. % to 45 wt. %, from 25 wt. % to 40 wt. %, from 30 wt. % to 35 wt. %, or any subset thereof, of the ethylene introduced to the high-pressure reactor 104 may be introduced through the second side inlet. From 20 wt. % to 40 wt. %, from 20 wt. % to 35 wt. %, from 20 wt. % to 30 wt. %, from 25 wt. % to 45 wt. %, from 30 wt. % to 45 wt. %, from 25 wt. % to 40 wt. %, from 30 wt. % to 35 wt. %, or any subset thereof, of the ethylene introduced to the high-pressure reactor 104 may be introduced through the third side inlet.

[0046] The total amount of ethylene fed to the high-pressure reactor 104 may comprise a mixture of recycled ethylene and fresh (“make-up”) ethylene. At least 40 wt. %, at least 50 wt. %, at least 60 wt. %, at least 70 wt. %, at least 80 wt. %, at least 90 wt. %, at least 95 wt. %, or at least 99 wt. % of the fresh ethylene supplied to the high-pressure reactor 104 may be introduced to the front of the high-pressure reactor 104.

[0047] Without being limited by theory, the effects shown herein for ethylene feed location are believed to be the strongest with fewer ethylene side streams (such as 3, 2 or 1), and, optionally, 3, 2, or 1 initiator injection points.

[0048] The initiator introduced to the high-pressure reactor 104 through one or more initiator feed streams 116, 118, 120 may comprise a compound capable of forming free radicals. The initiator may enter the high-pressure reactor 104 through dedicated injection ports or may be combined with ethylene side streams before entering the high-pressure reactor 104. Suitable initiators may include peroxides. Non-limiting examples of initiators include organic peroxides such as cyclic peroxides, diacyl peroxides, dialkyl peroxides, hydroperoxides, peroxycarbonates, peroxydicarbonates, peroxyesters, peroxyketals, t-butyl peroxy pivalate, di-t-butyl peroxide, t- butyl peroxy acetate and t-butyl peroxy-2-hexanoate, and combinations thereof. In an embodiment, these organic peroxy initiators are used may be an amount from 0.001 wt % to 0.2 wt %, on the basis of the total weigh of polymerizable monomers.

[0049] In embodiments, a chain transfer agent (CTA) system may be introduced at one or more points along the reactor. The term “CTA system” includes a single CTA, or a mixture of CTAs, added to the polymerization process, typically to control the melt index. A CTA system includes a component able to transfer a hydrogen atom to a growing polymer molecule containing a radical, by which a radical is formed on the CTA molecule, which can then initiate a new polymer chain. CTA is also known as telogen or telomer. The CTA system may include, by way of example and not limitation: propylene, isobutane, n-butane, 1 -butene, methyl ethyl ketone, acetone, ethyl acetate, propionaldehyde, ISOPAR (ExxonMobil Chemical Co.), and isopropanol. In an embodiment, the amount of CTAused in the process may be from 0.01 weight percent to 10 weight percent of the total reaction mixture.

[0050] The terms “CTA activity” or “chain transfer activity coefficient (Cs value)” as used herein, refer to the ratio between the “rate of chain transfer” to the “rate of ethylene propagation.” See Mortimer references provided in the experimental section below.

[0051] The terms “Zl/Zi” as used herein is determined as follows. The “reactor zone molar concentration of a CTAj in a reactor zone i ([CTA]ji)” is defined as the “total molar amount of that CTA fed (excluding a transfer from a previous reaction zone) into reactor zones k =1 to k = i” divided by the “total molar amount of ethylene fed (excluding a transfers from a previous reaction zone) into reactor zones 1 to i.” Note i > 1. This relationship is shown below in Equation AC.

unt of moles of the jth CTA freshly injected to the kth reactor zone (where k = 1 to i),” and

is the “amount of moles of ethylene freshly injected to the kth reactor zone (where k = 1 to i).”

[0054] The “transfer activity of a CTA (system) in a reactor zone I (Zi)” is defined as the “sum of the reactor zone molar concentration of each CTA in the reactor zone” multiplied with its chain transfer activity constant (Cs) - see Equation BC. The chain transfer activity constant (Cs) is the ratio of reaction rates Ks/Kp, at a reference pressure (1360 atm) and a reference temperature (130°C). This relationship is shown below in Equation BC, where Hcompi is the total number of CTAs in reactor zone i. Note i > 1, and n_COmpi > 1.

[0056] The term “Rn = RZl/RZn”, as used herein, refers to, for reaction zone n, the ratio of the “mole fraction of fresh ethylene fed to the first reaction zone (RZ1)” to the “mole fraction of fresh ethylene fed to reaction zone n (RZn)”.

[0057] In embodiments, all fresh (“make up”) CTA may be fed to the second reaction zone. In a second embodiment, the ratio of CTA/ethylene feed in each of the reaction zones, after the first reaction zone, is the same.

[0058] In embodiments, all fresh ethylene and up to 30 mol. % of fresh CTA, such as up to 25 mol. %, up to 20 mol. %, up to 15 mol. %, up to 10 mol. %, or up to 5 mol. %, or up to 1 mol. %, may be fed to the first reaction zone.

[0059] In embodiments, the concentration of CTA in the reaction zone 2 over reaction 1 (Z2/Z1) may be greater than 0.5, such as greater than 0.6, greater than 0.8, greater than 1.0, greater than 1.2, greater than 1.5, greater than 1.7, 0.5 to 1.8, 0.6 to 1.8, 0.8 to 1.8, 1.0 to 1.8, 1.2 to 1.8, 1.4 to 1.8, 1.6 to 1.8, 0.5 to 1.5, 0.5 to 1.2, 0.5 to 0.9, 0.7 to 1.3, or any subset thereof.

[0060] In embodiments, the concentration of CTA in the reaction zone 3 over reaction 1 (Z3/Z1) may be greater than 0.2, such as greater than 0.3, greater than 0.4, greater than 0.5, greater than 0.6, greater than 0.7, greater than 0.8, greater than 0.9, 0.2 to 1.0, 0.4 to 1.0, 0.6 to 1.0, 0.8 to 1.0, 0.2 to 0.8, 0.2 to 0.6, 0.2 to 0.4, 0.4 to 0.8, or any subset thereof.

[0061] In embodiments, the concentration of CTA in the reaction zone 4 over reaction 1 (Z4/Z1) may be greater than 0.2, such as greater than 0.3, greater than 0.4, greater than 0.5, greater than 0.6, greater than 0.7, 0.2 to 0.8, 0.4 to 0.8, 0.6 to 0.8, 0.2 to 0.6, 0.2 to 0.4, or any subset thereof.

[0062] The process may comprise feeding a mixture of hydrocarbon-based molecules into the high-pressure reactor 104. Each hydrocarbon-based molecule in the mixture of hydrocarbon-based molecules may consist of hydrogen atoms and carbon atoms.

[0063] Each hydrocarbon-based molecule in the mixture of hydrocarbon-based molecules may comprise three or more carbon-carbon double bonds. In embodiments, each hydrocarbon-based molecule may comprise from 3 to 40 carbon-carbon double bonds, such as at least 5, at least 7, at least 9, at least 12, from 3 to 30, from 3 to 20, from 3 to 18, from 3 to 14, from 3 to 12, from 3 to 5, from 5 to 40, from 7 to 40, from 9 to 40, from 12 to 40, from 12 to 20, or any subset thereof carbon-carbon double bonds.

[0064] The polymer chain of each of the hydrocarbon-based molecules may be branched and comprise three or more terminal ends. In embodiments, a carbon-carbon double bond may be present at each terminal end. Three or more of the carbon-carbon double bonds may be terminal groups. For example, at least 3, 5, 7, 9 12, or more of the carbon-carbon double bonds may be terminal groups.

[0065] The mixture of hydrocarbon-based molecules may comprise two or more hydrocarbonbased molecules which differ in structure, property, and/or composition.

[0066] The mixture of hydrocarbon-based molecules may have a number average molecular weight (Mn) of 350 g/ to 4000 g/mol, such as 400 to 4000 g/mol, 500 to 4000 g/mol, 800 to 4000 g/mol, 1000 to 4000 g/mol, 400 to 3000 g/mol, 400 to 2500 g/mol, 400 to 1500 g/mol, 800 to 1200 g/mol, or any subset thereof.

[0067] Some or all of the hydrocarbon-based molecules may have Structure I:

Structure I

[0068] In structure I, R = H or OH n (the number of terminal carbon-carbon double bonds) may be from 3 to 160, such as from 5 to 160, from 10 to 160, from 20 to 160, from 30 to 160, or from 40 to 160, from 5 to 100, or from 9 to 40; m (the number of internal carbon-carbon double bonds) may be from 0 to 50, such as from 0 to 30, from 1 to 50, from 1 to 40, from 1 to 30, from 1 to 20, from 2 to 20, from 2 to 10, or any subset thereof.

[0069] All or a portion of t the hydrocarbon-based molecules may have Structure II

Structure

II

[0070] In Structure II, R = H or OH, n (the number of terminal carbon-carbon double bonds) may be from 3 to 160, and m (the number of internal carbon-carbon double bonds) may be from 0 to 50; x may be from 0 to 160, and y may be from 0 to 50. For example, n may be from 3 to 160, such as from 5 to 160, from 10 to 160, from 20 to 160, from 30 to 160, or from 40 to 160, from 5 to 100, or from 9 to 40; m may be from 0 to 50, such as from 0 to 30, from 1 to 50, from 1 to 40, from 1 to 30, from 1 to 20, from 2 to 20, from 2 to 10, or any subset thereof. X may be from 0 to 160, such as from 0 to 140, from 0 to 120, from 0 to 100, from 0 to 80, from 0 to 60, from 0 to 40, from 0 to 20, from 1 to 20, from 1 to 60, from 1 to 100, from 1 to 160, from 10 to 150, from 20 to 140, from 40 to 120, from 60 to 100, or any subset thereof. Y may be from 0 to 40, from 0 to 30, from 0 to 20, from 0 to 10, from 1 to 50, from 5 to 50, from 10 to 60, from 20 to 50, from 30 to 50, from 40 to 50, from 10 to 40, or any subset thereof.

[0071] The average n content in the mixture of hydrocarbon-based molecules may be from 9 to 40, and the average m content may be from 1 to 10. The “average n content” is calculated by dividing the number average molecular weight (Mn) by the weight average molecular weight (Mw) of the hydrocarbon-based molecule, then multiplying by the fractional amount of terminal carbon-carbon double bonds. The “average m content” is calculated by dividing the number average molecular weight (Mn) by the weight average molecular weight (Mw) of the hydrocarbon-based molecule, then multiplying by the fractional amount of internal carbon-carbon double bonds. The mixture of hydrocarbon-based molecules may have respective average n content and average m content (denoted as “n/m”, see Structure I for each hydrocarbon-based molecule) as follows: 9-40/1-10, or 12-38/2-8, or 13-37/2-6, or 15-35/2-6, or 19/3, or 33/5. The hydrocarbon-based molecules of Structure I, the hydrocarbon-based molecules of Structure II, and/or the overall mixture of hydrocarbon-based molecules may have an m + n content of from 5 to 30, such as from 5 to 25, from 5 to 20, from 10 to 30, from 15 to 30, from 10 to 30, from 15 to 25, from 15 to 20, or any subset thereof.

[0072] The hydrocarbon-based molecules of Structure I, the hydrocarbon-based molecules of Structure II, and/or the overall mixture of hydrocarbon-based molecules may have a molecular weight distribution from 1.2 to 20, such as from 1.2 to 10, from 1.2 to 5, from 1.2 to 3, from 1.3 to 20, from 1.4 to 20, from 1.5 to 20, from 2 to 20, from 5 to 20, from 10 to 20, from 2 to 18, from 6 to 16, from 8 to 14, or any subset thereof.

[0073] In Structure I and Structure II, it should be understood that the hydrocarbon-based molecules may be random copolymers or block copolymers. The individual monomers may, but need not, be arranged in the same order as is shown in Structure I and Structure II. Any polymer which includes both the monomers shown in Structure I (and only those two monomers) is defined by structure I. Any polymer which includes all four of the monomers shown in Structure II (and only those monomers) is defined by structure II, regardless of the order of the monomers.

[0074] The mixture of hydrocarbon-based molecules may comprise hydrocarbon-based molecules of Structure I, Structure II, or a combination thereof. Suitable hydrocarbon-based molecules include those described in detail in U.S. Patent Application Number 17/294,538, the entirety of which is incorporated by reference herein; and include 1,2-polybutadienes, available from Nippon Soda Co., Ltd under the names PB B-1000 (a 1,2, -polybutadiene with a number average molecular weight (Mn) of 1200 and at least 85% 1,2-vinyl content), and PB B-2000 (a 1,2, -polybutadiene with a number average molecular weight (Mn) of 2000 and at least 90 % 1,2- vinyl content).

[0075] The mixture of hydrocarbon-based molecules may be introduced to the high-pressure reactor 104 in an amount such that a weight ratio of the mixture of hydrocarbon-based molecules to ethylene may be less 0.01 (1 wt. % mixture of hydrocarbon-based molecules on the basis of the total weight of ethylene introduced to the high-pressure reactor). In embodiments, a weight ratio of the mixture of hydrocarbon-based molecules to ethylene may be from 0.01 wt. % to 1 wt. %, from 0.05 wt. % to 1 wt. %, from 0.01 wt. % to 0.5 wt. %, from 0.01 wt. % to 0.3 wt. %, from 0.01 wt. % to 0.2 wt. %, from 0.05 wt. % to 0.15 wt. %, or any subset thereof, on the basis of the total weight of ethylene fed to the high-pressure reactor 104.

[0076] At least 40 wt. % of the mixture of hydrocarbon-based molecules may be fed to the front inlet of the high-pressure reactor 104. Without being limited by theory, it has been found that introducing at least 40 wt. % (such as all or substantially all) of the mixture of hydrocarbon-based molecules to the front inlet of the high-pressure reactor 104 may result in improved melt strength and molecular weight distributions at reduced concentrations of the mixture of hydrocarbon-based molecules, relative to introducing the mixture of hydrocarbon-based molecules at the one or more side inlets of the high-pressure reactor. In embodiments, at least 50 wt. %, at least 60 wt. %, at least 70 wt. %, at least 80 wt. %, at least 90 wt. %, at least 95 wt. %, at least 99 wt. %, or even at least 99.9 wt. % of the mixture of hydrocarbon-based molecules may be fed to the front inlet of the high-pressure reactor 104. It should be understood that the front inlet of the high-pressure reactor 104 is upstream of a first initiator injection point. In embodiments, the remainder of the mixture of hydrocarbon-based molecules may be fed to the high-pressure reactor in a second reaction zone.

[0077] In embodiments, the remainder of the mixture of hydrocarbon-based molecules not fed to the front of the high-pressure reactor 104 may be fed to one or more side inlets of the high- pressure reactor, in proportion with the amount of ethylene fed to that side inlet of the high- pressure reactor. For example, if 50 % of the total mixture of hydrocarbon based molecules is fed to the front of the reactor, 60 % of the ethylene fed to the side of the reactor is fed to the second reaction zone, and 40 % of the ethylene fed to the side of the reactor is fed to the third reaction zone, then 50 % of the total mixture of hydrocarbon-based molecules would be fed to the front of the reactor, 30 % of the total mixture of hydrocarbon-based molecules would be fed to the second reaction zone, and 20 % of the total mixture of hydrocarbon-based molecules would be fed to the third reaction zone.

[0078] The majority (such as all or substantially all) of the mixture of hydrocarbon-based molecules may be fed to the high-pressure reactor 104 downstream of the at least one hypercompressor 102. Without being limited by theory, it has been found that introducing the mixture of hydrocarbon-based molecules to the hyper-compressor 102 can result in increased fouling of the hyper compressor. Generally, this phenomenon of increased fouling has been found to be exacerbated by the presence of ethylene during the pressurization of the mixture of hydrocarbonbased molecules. In embodiments, at least 50 wt. %, at least 60 wt. %, at least 70 wt. %, at least 80 wt. %, at least 90 wt. %, at least 95 wt. %, at least 99 wt. %, or even at least 99.9 wt. % of the mixture of hydrocarbon-based molecules may be fed to the high-pressure reactor 104 at a point downstream of the at least one hyper-compressor 102. The mixture of hydrocarbon-based molecules may be pressurized to the working pressure of the high-pressure reactor 104 (such as at least 1000 bar, at least 1200 bar, at least 1500 bar, at least 1700 bar, at least 2000 bar, from 1000 bar to 4000 bar, from 1700 bar to 4000 bar, from 2000 bar to 4000 bar, from 2000 bar to 3200 bar, or any subset thereof) in the presence of less than 0.1 mol. % (such as less than 0.01 mol. %, less than 0.001 mol. %, or even less than 0.00001 mol. %) of ethylene, on the basis of the total moles of gas in the pressurization device (such as a pump).

[0079] The mixture of hydrocarbon-based molecules may be pressurized while either diluted with hydrocarbon solvent, heated (such as to a temperature of at least 40 °C or at least 50 °C), or both.

[0080] The process may comprise polymerizing the ethylene and the mixture of hydrocarbonbased molecules in a high-pressure reactor 104, thereby producing low-density polyethylene (TDPE). The high-pressure reactor 104 may be a tubular reactor or an autoclave reactor. Where an autoclave reactor is used, the autoclave reactor may be an agitated autoclave reactor having one or more reaction zones. The autoclave reactor may have several injection points for initiator or monomer feeds, or both. Where a tubular reactor is used as the high-pressure reactor 104, the tubular reactor may comprise a jacketed tube with one or more reaction zones. Suitable reactor lengths may be from 100 m to 3000 m, or from 1000 m to 2000 m. The beginning of a reaction zone, for either type of reactor, is typically defined by the side injection of either initiator of the reaction, ethylene, chain transfer agent (or telomer), comonomer(s), as well as any combination thereof. A high-pressure process can be carried out in autoclave reactors or tubular reactors having one or more reaction zones, or in a combination of autoclave reactors and tubular reactors, each comprising one or more reaction zones.

[0081] The process may comprise producing the LDPE via free radical polymerization at a pressure of at least 1000 bar, such as at least 1200 bar, at least 1500 bar, at least 1700 bar, at least 2000 bar, from 1000 bar to 4000 bar, from 1200 bar to 4000 bar, from 1500 bar to 4000 bar, from 1700 bar to 4000 bar, from 2000 bar to 4000 bar, from 2000 bar to 3200 bar, or any subset thereof. Without being limited by theory, it has been found that lower pressures may be used to produce LDPE when using an autoclave reactor than when using a tubular reactor. In embodiments, the high-pressure reactor 104 may be an autoclave reactor and the free radical polymerization may occur at a pressure of from 1500 bar to 4000 bar. In embodiments, the high-pressure reactor 104 may be a tubular reactor and the free radical polymerization may occur at a pressure of from 2000 bar to 4000 bar.

[0082] The LDPE may be formed via free radical polymerization at a peak reaction temperature of from 270 °C to 320 °C, such as 275 °C to 320 °C, 280 °C to 320 °C, 285 °C to 320 °C, 290 °C to 320 °C, 295 °C to 320 °C, 300 °C to 320 °C, 275 °C to 315 °C, 275 °C to 310 °C, 275 °C to 305 °C, 275 °C to 300 °C, or any subset thereof.

[0083] The LDPE may be formed via free radical polymerization with an initial to peak temperature differential of from 130 °C to 170 °C, such as 130 °C to 165 °C, 130 °C to 160 °C, from 130 °C to 155 °C, from 130 °C to 150 °C, from 130 °C to 145 °C, from 135 °C to 170 °C, from 140 °C to 170 °C, 145 °C to 170 °C, or any subset thereof.

[0084] The process may result in the conversion of at least 50 wt. % of the mixture of hydrocarbon-based molecules, such as at least 55 wt. %, at least 60 wt. %, at least 65 wt. %, at least 68 wt. %, or at least 70 wt. %, on the basis of the total quantity of the mixture of hydrocarbonbased molecules introduced to the reactor.

[0085] The LDPE may have a melt strength of at least 20 mN, such as at least 25 mN, at least 30 mN, at least 35 mN, at least 40 mN, at least 50 mN, or at least 60 mN.

[0086] The LDPE may have a Mw/Mn (also referred to herein as “molecular weight distribution” and “polydispersity index”) of at least 9.0, such as at least 10.0, at least 11.0, at least 12.0, at least 14.0, at least 16.0, at least 18.0, at least 20.0, from 9.0 to 25, from 10 to 25, from 11 to 25, from 12 to 25, from 14 to 25, or any subset thereof. Mw/Mn may be determined by conventional Gel Permeation Chromatography-Size Exclusion Chromatography.

[0087] The LDPE may have a melt flow rate (h) (also referred to herein as “melt index (I2)”) of 0.1 g/10 min to 100 g/10 min, such as from 0.5 g/10 min to 100 g/10 min, from 1 g/10 min to 100 g/10 min, from 2 g/10 min to 100 g/10 min, from 3 g/10 min to 100 g/10 min, from 4 g/10 min to 100, from 0.1 g/10 min to 75 g/10 min, from 0.1 g/10 min to 50 g/10 min, from 0.1 g/10 min to 25 g/10 min, from 0.1 g/10 min to 12 g/10 min, from 0.1 g/10 min to 8 g/10 min, from 0.1 g/10 min to 6 g/10 min, from 1 g/10 min to 10 g/10 min, from 2 g/10 min to 8 g/10 min, from 3 g/10 min to 5 g/10 min, or any subset thereof.

[0088] The EDPE may have a density of 0.916 g/cm³ to 0.924 g/cm³, such as 0.916 to 0.922 g/cm³, 0.916 to 0.920 g/cm³, 0.916 to 0.918 g/cm³, 0.917 to 0.924 g/cm³, or 0.919 to 0.924 g/cm³.

[0089] The EDPE may have a hexane extractable content of less than 2.6 wt. %, such as less than 2.5 wt. %, less than 2.25 wt. %, less than 2.0 wt. %, less than 1.5 wt. %, less than 1 wt. %, or even less than 0.5 wt. %, on the basis of the total weight of the polymer.

[0090] The EDPE may have a neck in of 1.0 to 3.0 in, such as 1.25 to 3.0 in, 1.5 to 3.0 in, 1.75 to 3.0 in, 2.0 to 3.0 in, 1.0 to 2.75 in, 1.0 to 2.5 in, 1.0 to 2.25 in, 1.0 to 2.0 in, or any subset thereof. Neck in is calculated at a draw down rate of 440 feet per minute (fpm).

[0091] The EDPE may have a draw down of 800 to 1500 fpm, such as 900 to 1500 fpm, 1000 to 1500 fpm, 1200 to 1500 fpm, 800 to 1400 fpm, 800 to 1300 fpm, 800 to 1100 fpm, or any subset thereof.

[0092] It should be understood that these melt strengths, molecular weight distributions, and melt flow rates may be achieved at a ratio of the total weight of the mixture of hydrocarbon-based molecules to the total weight of ethylene introduced to the high-pressure reactor less 0.01 (1 wt. % mixture of hydrocarbon-based molecules on the basis of the total weight of ethylene introduced to the high-pressure reactor), such as less than or equal to 0.001 (0.1 wt. %).

TEST METHODS

[0093] Melt Flow Rate (Melt Index) [0094] Melt indices I2 of polymer samples were measured in accordance to ASTM D-1238 (method B) at 190 °C and at 2.16 kg load, respectively.

[0095] Density

[0096] Samples for density measurement were prepared according to ASTM D4703. Measurements were made, according to ASTM D792, Method B, within one hour of sample pressing.

[0097] Gg Pgrme tipn C

Size Exclusion Ch^

and absolute GPC)

[0098] The GPC-SEC (Conventional and Absolute GPC) measurements were performed according to the test procedure defined in PCT Publication WO2021108134.

[0099] Melt Strength

[0100] The melt strength measurements were determined according to the test procedure defined in PCT Publication W02020112873.

[0101] Melt Force

[0102] The melt force measurements were performed according to the test procedure defined in PCT Publication WO2021108134.

[0103] Hexane Extractables

[0104] The concentration of hexane extractables were determined according to the test procedure described in U.S. Patent No. US9334348B2.

[0105] Neck In and Draw Down

[0106] Neck-in and draw-down were determined as follows: Draw down is defined as the maximum line speed attainable before web breakage or web defects/edge inconsistencies occur, when accelerating the line speed at a constant polymer output. Neck-in is the difference between the final width of the web and the die width at fixed line speed. Neck-in was determined at a draw down rate of 440 fpm. Tower neck-in and higher draw down are both very desirable. Tower neck- in indicates better dimensional stability of the web, which, in turn, provides for better control of the coating onto the substrate. Higher draw down indicates higher line speed capability, which, in turn, provides for better productivity.

[0107] Polymerization Simulations [0108] The polymerization simulations were performed according to the procedure described in U.S. Patent No. US10005863B2.

[0109] Simulated Melt Force: An empirical model has been developed to predict melt force of the simulated polymers using JMP software. The JMP modeling in essence is a straightforward statistical optimization technique where the equations have been selected based on insights into the physical dependence of the melt strength/ melt force on the inputs such as Mw, Mn, SCB, FCB, broadening factor (when adding the branching agent). The numerical coefficients in the equations are then unambiguously established by a least-square optimization of the output values given the input values of the relevant quantities.

EXAMPLES

[0110] Materials

[0111] In all examples, polybutadiene was used as the mixture of hydrocarbon-based molecules. Specifically, the polybutadiene used was PB B-1000, supplied by Nippon Soda, Co., Ltd. PB B- 1000 has an Mn of 1200 g/mol, a Mw/Mn of 1.47, 85 % terminal carbon-carbon double bonds, 15 % internal carbon-carbon double bonds, an average n content of 19 and an average m content of 3. “m” and “n” were calculated by dividing Mn over the Mw of butadiene monomer (hydrocarbonbased molecule) and multiplying by fractional amount of terminal carbon-carbon double bonds for n, and internal carbon-carbon double bonds for m. For example: Mn=1200 g/mol, Avg n=(1200 g/mol)/(54.09 g/mol butadiene monomer)=22 repeat units*0.85 (terminal /total alkene)=18.8 terminal vinyl groups per chain on average.

[0112] Example 1

[0113] In a first example, a series of sample LDPEs were formed according to the presently described methods. PB B-100, as described above, was used as the mixture of hydrocarbon-based molecules. The mixture of hydrocarbon-based molecules was combined in the amounts shown in FIG. 2 with ethylene. 50 wt. % of the ethylene was fed to the front inlet of the tubular reactor and 50 % of the ethylene was fed to the first side inlet of the tubular reactor, at a reactor inlet pressure of about 2100 bar and a peak temperature in all reaction zones of about 295 °C. Initiator was fed a first initiator injection point upstream of the first side inlet. The mixture of hydrocarbon-based molecules was fed to the front inlet of the reactor in one example and to the side of the reactor in the other example. [0114] As can be seen from FIG. 2, increasing the concentration of the mixture of hydrocarbonbased molecules increases the melt strength of the LDPE produced whether the mixture of hydrocarbon-based molecules is supplied to the front or the side of the reactor. As can be seen from FIG. 2, the effect is substantially more pronounced when at least 40 wt. % (such as all of) the mixture of hydrocarbon-based molecules is fed to the front of the reactor, enabling higher melt strengths at lower concentrations of hydrocarbon-based molecules.

[0115] Example 2

[0116] Referring now to FIG. 3, a reference LDPE (CE-A) was formed in the same manner as in Example 1 except no branching agent was added. Then, a comparative LDPE (CE-B) was formed in the same manner as Example 1, however PB B-1000 branching agent was added to the side of the reactor, with a total branching agent concentration of 0.4, on the basis of the total weight of ethylene. Finally, an LDPE (EX-1) was formed in the same manner as Example 1, however PB B-1000 branching agent was added to the front of the reactor, with a total branching agent concentration of 0.36, on the basis of the total weight of ethylene.

[0117] As can be seen from FIG. 3, the introduction of branching agent to the front of the reactor caused a substantial broadening of the molecular weight distribution of the LDPE, relative to both the reference example CE-A and the comparative example CE-B.

[0118] Example 3

[0119] For all the processes shown in Example 3, PB B-1000 was used as the mixture of hydrocarbon-based molecules. The reactors were run under the conditions shown in Table 1. Results are shown in Table 2.

[0120] As used in Table 2, the feed location “hyper suction” refers to directly upstream of the hyper-compressor. The feed location “hyper discharge” refers to downstream of the hypercompressor, such as between the hyper-compressor and the high-pressure reactor, or to the inlet of the high-pressure reactor.

Table 1A

Table IB

Table 2

[0121] GPC testing was performed, the results of which are shown in Table 3.

Table 3

[0122] As can be seen in Table 3, the embodiments of the present disclosure which feed at least 40 % of the mixture of hydrocarbon based molecules to the front of the reactor result in increases in all of the higher molecular weight moments (Mw, Mz, and Mz+1). These higher molecular weight moments are believed to correlate with increased melt force.

[0123] For the purposes of describing and defining the present disclosure it is noted that the terms “about” or “approximately” are utilized in this disclosure to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The terms “about” and/or “approximately” are also utilized in this disclosure to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

[0124] It is noted that one or more of the following claims utilize the term “wherein” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”

[0125] Any quantitative value expressed in the present application may be considered to include open-ended embodiments consistent with the transitional phrases “comprising” or “including” as well as closed or partially closed embodiments consistent with the transitional phrases “consisting of’ and “consisting essentially of.”

[0126] It is also noted that recitations herein of “at least one” component, element, etc., should not be used to create an inference that the alternative use of the articles “a” or “an” should be limited to a single component, element, etc.

Claims

1. A process for producing low-density polyethylene (LDPE), the process comprising: feeding ethylene into a front inlet of a high-pressure reactor at a pressure of at least 1000 bar; feeding ethylene into one or more side inlets of the high-pressure reactor at a pressure of at least 1000 bar; and feeding a mixture of hydrocarbon-based molecules into the high-pressure reactor downstream of the at least one hyper-compressor, each hydrocarbon-based molecule comprising three or more carbon-carbon double bonds; wherein: at least 20 wt. % of a total amount of ethylene fed to the high-pressure reactor is fed to the front inlet of the high-pressure reactor; at least 20 wt. % of the total amount of ethylene fed to the high-pressure reactor is fed to a first side inlet of the high-pressure reactor; at least 40 wt. % of the mixture of hydrocarbon-based molecules is fed to the front inlet of the high-pressure reactor, thereby producing the LDPE via free radical polymerization at a pressure of at least 1000 bar.

2. The process for the production of LDPE of claim 1, further comprising feeding an initiator to the high-pressure reactor between the front inlet and the first side inlet.

3. The process for the production of LDPE of either of claims 1 or 2, wherein: the high pressure reactor comprises at least three reaction zones; a ratio of Z2/Z1 is from 0.5 to 1.8; a ratio of Z3/Z1 is from 0.2 to 1.0; and a ratio of Z4/Z1 is from 0.2 to 0.8.

4. The process for the production of LDPE of any one of claims 1 to 3, further comprising: feeding an initiator to the high-pressure reactor between the first side inlet and the second side inlet; and feeding ethylene to a second side inlet of the high-pressure reactor.

5. The process for the production of TDPE of any one of claims 1 to 4, wherein a ratio of the total weight of the mixture of hydrocarbon-based molecules to the total weight of ethylene introduced to the high-pressure reactor is less 0.01.

6. The process for the production of TDPE of any one of claims 1 to 5, wherein the mixture of hydrocarbon-based molecules has a number average molecular weight (Mn) of 350 g/mol to 4000 g/mol.

7. The process for the production of TDPE of any one of claims 1 to 6, wherein the hydrocarbon-based molecules have the Structure I:

Structure

wherein R is H or OH, n is from 3 to 160, and m is from 0 to

50.

8. The process for the production of TDPE of any one of claims 1 to 7, wherein the hydrocarbon-based molecules have the Structure II:

Structure II

wherein R is H or OH, n is from 3 to 160, and m is from 0 to 50; x is from 0 to 160, and y is from 0 to 50.

9. The process for the production of LDPE of any one of claims 1 to 8, wherein the mixture of hydrocarbon-based molecules has a molecular weight distribution from 1.2 to 10.

10. The process for the production of TDPE of any one of claims 1 to 9, wherein the high- pressure reactor is a tubular reactor.

11. The process for the production of TDPE of any one of claims 1 to 10, wherein the LDPE has a melt force of at least 20 mN.

12. The process for the production of LDPE of any one of claims 1 to 11, wherein the LDPE has a Mw/Mn of at least 9.0.

13. The process for the production of LDPE of any one of claims 1 to 12, wherein the LDPE has a melt flow rate (E) of 0.1 g/10 min to 100 g/10 min.

14. The process for the production of LDPE of any one of claims 1 to 13, wherein the LDPE has a density of from 0.9160 g/cm³ to 0.9240 g/cm³.

15. An LDPE resin produced from the process of any preceding claim.