Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F110/02—Ethene
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/24—Stationary reactors without moving elements inside
  • B01J19/2415—Tubular reactors
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/001—Multistage polymerisation processes characterised by a change in reactor conditions without deactivating the intermediate polymer
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/01—Processes of polymerisation characterised by special features of the polymerisation apparatus used
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F4/00—Polymerisation catalysts
  • C08F4/28—Oxygen or compounds releasing free oxygen
  • C08F4/32—Organic compounds
  • C08F4/38—Mixtures of peroxy-compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/06—Polyethene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2400/00—Characteristics for processes of polymerization
  • C08F2400/02—Control or adjustment of polymerization parameters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2500/00—Characteristics or properties of obtained polyolefins; Use thereof
  • C08F2500/08—Low density, i.e. < 0.91 g/cm3
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2500/00—Characteristics or properties of obtained polyolefins; Use thereof
  • C08F2500/12—Melt flow index or melt flow ratio
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2500/00—Characteristics or properties of obtained polyolefins; Use thereof
  • C08F2500/17—Viscosity
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2207/00—Properties characterising the ingredient of the composition
  • C08L2207/06—Properties of polyethylene
  • C08L2207/066—LDPE (radical process)
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/582—Recycling of unreacted starting or intermediate materials

Definitions

• Resins for extrusion coating on paper, board, aluminum, etc. are designed with broad molecular weight distribution and low extractables.
• the polymer In extrusion coating applications, the polymer is processed at high temperature conditions, typically above 280°C and below 350°C.
• Broad molecular weight distribution (MWD) resins with a very high molecular weight fraction are used for good processability during coating (neck-in and drawdown balance).
• Low extractables are needed to reduce undesirable taste and odor, and to reduce smoke formation during the processing of the resin, especially during the high coating temperatures.
• LDPE low density polyethylene
• resins with broad MWD are made using autoclave reactors or a combination of autoclave and tube reactors.
• Broad MWD resins can be made by promoting long chain branching, and through the inherent residence time distribution, by which molecules will undergo shorter (low molecular weight) or longer (high molecular weight) growth paths.
• Broad MWD autoclave resins for LDPE extrusion coatings are focused in two product density regimes, namely from 0.915 to 0.919 g/cc and from 0.919 to 0.924 g/cc.
• This invention describes improved broad MWD tubular reactor products designed for the higher density regime from 0.919 to 0.924 g/cc.
• the autoclave and tubular reactor systems differ in residence time distribution, which is more uniform for tubular reactors and dispersed for autoclave reactor zones.
• the uniform residence time leads to narrower MWD, and very broad MWD can only be achieved in tubular reactors by applying extremely differentiated polymerization conditions, for example, as described in WO 2013/078018, and/or application of a branching/cross-linking agent, for example, as described in US7820776.
• the use of extreme process conditions and/or costly branching/cross-linking agents can lead to high melt strength tubular low density polyethylene, suitable for extrusion coating applications; however with elevated extractables.
• Undesirable gels in the polymer can result from the use of branching or cross-Unking agents. Due to the difference in cooling capability, the conversion level ranges, typically, from less than 20% (autoclave) to more than 30% (tubular).
• U.S. Publication No. 2008/0242809 discloses a process for preparing an ethylene copolymer, where the polymerization takes place in a tubular reactor, at a peak temperature between 290°C and 350°C.
• the comonomer is a di- or higher functional (meth)acrylate.
• the invention provides an ethylene homopolymer formed from a free-radical, high pressure polymerization process in a tubular reactor system, said homopolymer comprising the following properties:
• Figure 1 is a flow diagram for Inv. Exs. 1 to 5.
• Figure 2 is a flow diagram for Inv. Exs. 6 to 13 and Comp. Ex 13.
• Figure 3 is a flow diagram for Comp. Exs. 6, 10 and 11.
• Figure 4 is a flow diagram for Comp. Exs. 7 and 12.
• Figure 5 is a flow diagram for Comp. Exs. 3 to 5, 8 and 9.
• Ethylene homopolymers have been discovered that have densities > 0.9190 g/cc with broad MWD, high G' value and at reduced extractable levels in a tubular reactor at high ethylene conversion levels, and which are cost effective to make, not requiring additional costs associated with modifying or branching agents. These inventive ethylene homopolymers are described above. An inventive homopolymer may comprise a combination of two or more embodiments described herein.
• the ethylene-based homopolymer has a melt index (I 2 ) from 1.0 to 18 dg/min, or from 1.5 to 15 dg/min, or from 2 to 12 dg min. In one embodiment the ethylene-based polymer has a density > 0.9190 grams per cubic centimeter (g cc or g cm 3 ). In one embodiment the ethylene-based polymer has a density ⁇ 0.9245, or ⁇ 0.9240, or ⁇ 0.9235, or ⁇ 0.9230 g cc. In one embodiment the ethylene-based polymer has a density from 0.9190 to 0.9240 g/cc, or from 0.9195 to 0.9235, or from 0.9200 to 0.9230, g/cc.
• the ethylene homopolymer has a hexane extractable level that is greater than the lower of one of the following:
• the ethylene homopolymer has a vinyl content less than, or equal to, 0.15 vinyl groups per 1000 total carbons.
• the invention also provides a composition comprising an inventive ethylene homo polymer as described herein.
• the composition further comprises another ethylene-based polymer that differs from the inventive ethylene-based polymer in one or more properties, for example, density, melt index (I 2 ), weight average molecular weight (Mw(conv)), number average molecular weight (Mn(conv)), and/or Mw(conv)/Mn(conv).
• An inventive composition may comprise one or more additives, such as stabilizers (e.g., antioxidants), plasticizers, antistatic agents, pigments, dyes, nucleating agents, fillers, slip agents, fire retardants, processing aids, smoke inhibitors, viscosity control agents and anti-blocking agents.
• additives such as stabilizers (e.g., antioxidants), plasticizers, antistatic agents, pigments, dyes, nucleating agents, fillers, slip agents, fire retardants, processing aids, smoke inhibitors, viscosity control agents and anti-blocking agents.
• the polymer composition may, for example, comprise less than 10 wt% of the combined weight of one or more additives, based on the weight of the composition.
• the invention also provides an article comprising at least one component formed from an inventive composition.
• the article is a film or a coating, for example, an extrusion coating.
• the article is a film.
• the article is a coating.
• the article is a coating for a cable or wire.
• the article is a coated sheet, and in a further embodiment the sheet is selected from a metal, a paper, or another polymer substrate or combinations thereof.
• the coated sheet is used in a wire or cable configuration.
• the coated sheet is used in a packaging application.
• the coated sheet is used in a food packaging application, and further the coated sheet is used in a cook-in food packaging application.
• An inventive ethylene-based polymer may comprise a combination of two or more embodiments as described herein.
• An inventive composition may comprise a combination of two or more embodiments as described herein.
• An inventive article may comprise a combination of two or more embodiments as described herein.
• the invention also provides a process for producing the ethylene homopolymer of any one of the previous claims, the process comprising polymerizing a reaction mixture comprising ethylene and at least one free radical, in a reaction configuration, comprising a first tubular reaction zone 1 and a last tubular reaction zone i, in which i is greater than, or equal to, (>) 3, and under high pressure polymerization conditions (> 1000 bar (100 MPa))neig and wherein the "inlet pressure of the polymerization" is greater than, or equal to, [1800 Bar + (100 Bar x # of reaction zones)].
• x > 3, or > 4, or > 5, or > 6.
• the first tubular reaction zone 1 has a peak temperature of >
• the last tubular reaction zone i has a peak temperature of ⁇ 290°C, or > 300°C, or > 310°C.
• the reactor configuration comprises at least four reaction zones (i is > 4), and further, these zones can be located in one tubular reactor or spread over two or more tubular reactors. Typically, each tubular reactor comprises multiple reaction zones.
• a tubular reactor is a jacketed tube having one or more reaction zones is used as a reactor.
• reactor lengths may be from 100 to 3600 meters (m), or from 1000 to 2800 m.
• a CTA system comprises one or more CTAs.
• CTAs typically comprise at least one of the following groups: alkanes, aldehydes, ketones, alcohol, ether, esters, mercaptan or phosphine, and further an alkane, a ketone, an aldehyde, an alcohol or ether.
• CTAs include, but are not limited to, isobutane, n- butane, methyl ethyl ketone, acetone, ethyl acetate, propionaldehyde, ISOPAR-C, -E, and -H (ExxonMobil Chemical Co.), and isopropanol; and further propionaldehyde, butane and isobutane.
• the CTA is preferably not propylene or another alkene.
• the amount of CTA used is from 0.01 to 10 weight percent based on the weight of the total reaction mixture.
• the overall Cs value of the applied CTA systems is ⁇ 0.020 (e.g., propylene, acetone,), or ⁇ 0.010 (i.e., cyclohexane), or ⁇ 0.008 (e.g., isobutane, ethanol), or ⁇ 0.006 (e.g., n-butane, ethylacetate), as measured by Mortimer et al., at 130°C and 1360 atmospheres.
• ⁇ 0.020 e.g., propylene, acetone,
• ⁇ 0.010 i.e., cyclohexane
• ⁇ 0.008 e.g., isobutane, ethanol
• ⁇ 0.006 e.g., n-butane, ethylacetate
• a first CTA system having a transfer activity of Zl is fed into tubular reaction zone 1 and a second CTA system having a transfer activity of Zi is fed into tubular reaction zone i, and the Zl/Zi ratio is > 0.7, or > 0.8.
• a first CTA system having a transfer activity of Zl is fed into tubular reaction zone 1 and a second CTA system having a transfer activity of Zi, is fed into tubular reaction zone i, and the Zl/Zi ratio is ⁇ 1.3, or ⁇ 1.2.
• a first CTA system having a transfer activity of Zl is fed into tubular reaction zone 1 and a second CTA system having a transfer activity of Zi is fed into tubular reaction zone i, and the Zl/Zi ratio is less than, or equal to, (0.8-0.2*log (Cs)), wherein Cs is in the range of 0.0001 and 10, or from 0.0010 to 8.0, or from 0.0050 to 6.0, or from 0.010 to 1.00, or from 0.010 to 0.500.
• Cs is in the range of 0.0001 and 10, or from 0.0010 to 8.0, or from 0.0050 to 6.0, or from 0.010 to 1.00, or from 0.010 to 0.500.
• the Zl/Zi ratio (wherein i ⁇ 3 and i is the last reaction zone) is ⁇ 1.3, or ⁇ 1.2, or ⁇ 1.1. In one embodiment the Zl/Zi ratio, wherein i ⁇ 3 and i is the last reaction zone, is > 0.1, or > 0.2, or less than or equal to 0.3. In one embodiment Zl/Zi is ⁇ (0.8-0.2*log (Cs)), wherein Cs is in the range of 0.0001 and 10. In one embodiment Zl/Zi is ⁇ (0.75-0.2*log (Cs)), wherein Cs is in the range of 0.0001 and 10.
• Zl/Zi is ⁇ (0.7-0.2*log (Cs)), wherein Cs is in the range of 0.0001 and 10.
• the process includes a high pressure and low pressure recycle loop to improve ethylene efficiency, since ethylene is only partially converted or consumed per reactor pass. Typically, the conversion level per reactor pass is from 20% to 40%.
• the polymerization may take place in a tubular reactor as described WO2013/059042, which discloses a multi-zone reactor and alternate locations of feeding ethylene to control the ethylene to CTA ratio and therefore polymer properties. Ethylene may be simultaneously added in multiple locations to achieve the desired ethylene to CTA ratio.
• CTA addition points may be carefully selected to control polymer properties as described WO2013/078018.
• CTA may be simultaneously added in multiple locations to achieve the desired CTA to ethylene ratio.
• chain transfer agent is added to the first or second or first and second reaction zones.
• the ethylene fed to the first reaction zone is at least 10 wt% of the total ethylene fed to the polymerization. In one embodiment, the ethylene fed to the first reaction zone is from 10 to 100, or from 20 to 80, or from 25 to 75, or from 30 to 70, or from 40 to 60 wt% of the total ethylene fed to the polymerization.
• a free radical initiator refers to a free radical generated by chemical and/or radiation means.
• exemplary free radical initiators include organic peroxides, including cyclic peroxides, diacyl peroxides, dialkyl peroxides, hydroperoxides, peroxycarbonates, peroxydicarbonates, peroxyesters, and peroxyketals.
• Preferred initiators are t-butyl peroxy pivalate, di-t-butyl peroxide, t-butyl peroxy acetate and t-butyl peroxy-2- hexan-oate, or mixtures thereof.
• these organic peroxide initiators are used in an amount from 0.001 to 0.2 wt%, based upon the weight of polymerizable monomers.
• an initiator is added to at least one reaction zone, and the initiator has a half-life temperature, at one second, > 255°C, or > 260°C.
• such initiators are used at a peak polymerization temperature from 320°C to 350°C.
• the initiator comprises at least one peroxide group incorporated in a ring structure, such as TRIGONOXTM 301 (3,6,9-triethyl-3,6,9-trimethyl- 1,4,7- triperoxonaan) and TRIGONOXTM 311 (3,3,5,7,7-pentamethyl-l,2,4-trioxepane), both available from Akzo Nobel, and HMCH-4-AL (3,3,6,6,9,9-hexamethyl-l,2,4,5-tetroxonane) from United Initiators. See also WO 02/14379 and WO 01/68723.
• the or peak temperature for each reaction zone is from 150°C to 360°C, or from 170°C to 350°C, or from 200°C to 340°C.
• the peak temp, in the first reaction zone is > the peak temp, in each subsequent or consecutive reaction zone.
• the peak temp, in the first reaction zone is > 300°C, or > 310°C, or > 320°C.
• the peak temp, in the first reaction zone is at least 10°C, or 20°C, or 30°C greater than the peak temp, of each consecutive reaction zone.
• the temp, of the first reaction zone is > 320°C, or > 330°C, or > 340°C.
• the temp, of the last reaction zone is ⁇ 290°C, or ⁇ 280°C, or ⁇ 270°C.
• the polymerization temp, difference between the first and last reaction zone is > 30°C, or > 40°C, or > 50°C.
• the difference in polymerization temp, between any two successive reaction zones, e.g., the difference between the first and second reaction zones, or the second and third reaction zones, etc., over the length of the reaction configuration is > 10°C, or > 20°C, or > 30°C.
• the polymerization temp, difference between each successive reaction zone, e.g., the difference between the first and second reaction zones, and the second and third reaction zones, etc., over the length of the reaction configuration is > 10°C, or > 20°C, or > 30°C.
• the ratio of the polymerization temp, of the first reaction zone (e.g., 320°C) to the last, or ⁇ ⁇ , reaction zone (e.g., 290°C) is > 1.1, or > 1.2, or > 1.3.
• the peak temp, of the last reaction zone is ⁇ the peak temp, of each prior reaction zone.
• the polymerization pressure as measured at the first inlet of the reactor is from 1000 bar to 3600 bar, or from 1200 bar to 3500 bar, or from 1500 to 3400 bar, or from 2000 to 3200 bar.
• An inventive process may comprise a combination of two or more embodiments as described herein.
• composition includes a mixture of materials, which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.
• blend or “polymer blend,” as used, refers to a mixture of two or more polymers. A blend may or may not be miscible (not phase separated at molecular level). A blend may or may not be phase separated.
• polymer refers to a compound prepared by polymerizing monomers, whether of the same or a different type.
• the generic term polymer thus embraces the term homopolymer (which refers to polymers prepared from only one type of monomer, with the understanding that trace amounts of impurities can be incorporated into the polymer structure), and the term “interpolymer” as defined below. Trace amounts of impurities may be incorporated into and/or within the polymer. Trace amount of impurities can include initiator residues and other components, like for instance lubrication oil, solvent etc., showing chain transfer activity.
• interpolymer refers to polymers prepared by the polymerization of at least two different types of monomers.
• interpolymer includes copolymers (which refers to polymers prepared from two different monomers), and polymers prepared from more than two different types of monomers.
• ethylene-based polymer refers to a polymer that comprises a majority amount of polymerized ethylene, based on the weight of the polymer, and, optionally, at least one comonomer.
• ethylene-based interpolymer refers to an interpolymer that comprises a majority amount of polymerized ethylene, based on the weight of the inter- polymer, and at least one comonomer.
• ethylene-based copolymer refers to a copolymer that comprises a majority amount of polymerized ethylene, based on the weight of the interpolymer, and a comonomer as the only monomer types.
• free-radical, high pressure polymerization process refers to a polymerization process carried out at an elevated pressure of at least 1000 bar (100 MPa), and in the presence of at least one free-radical.
• reactor system refers to the devices used to polymerize and isolate a polymer. Such devices include, but are not limited to, one or more reactors, one or more feed streams, reactor pre-heater(s), monomer-reactor cooling device(s), Secondary compressor(s) (or Hyper compressor(s)), Primary compressor(s), and/or Booster compres- sor(s).
• reactor pre-heater refers to a reactor system that comprises only one or more tubular reactor(s) as the reactor(s) of the reactor system, and exclude autoclave reactors. When more than one tubular reactor is used, they are preferably used in a series configuration.
• reactor configuration refers to one or more reactors, and optionally one or more reactor pre-heaters, used to polymerize a polymer. The reactors may be jacketed.
• inlet pressure refers to the pressure level at the inlet of the first reaction zone.
• reaction zone refers to a reactor zone where polymeriza- tion reaction is initiated or reinitiated by the addition of free radicals or components which dissociate into and/or generate free radicals.
• reaction medium is heated and/or cooled by a heat transfer medium flowing through a jacket around the reactor.
• a reaction zone typically begins with the addition of make-up and/or recycled ethylene, and/or free radicals or components which dissociate into and/or generate free radicals.
• first reaction zone refers to the first reactor zone where the polymerization is initiated by the addition of radicals and/or components which dissociate into and/or generate radicals.
• the first reaction zone ends at the point where there is a new feed of radicals, and/or components which dissociate into and/or generate radicals, and, optionally, make-up, recycled ethylene, CTA(s), solvent(s) and/or comonomer(s).
• subsequent reaction zone refers to a reactor zone which receives ethylene and polymer from a previous reactor zone, and where radicals or components which dissociate into and/or generate radicals are added at the inlet of the subsequent (or sequential) reactor zone.
• the subsequent reaction zone ends at the point where there is a new feed of make-up and/or recycled ethylene, radicals, and/or components which dissociate into and/or generate, radicals; however, the nth reaction zone ends at the position of a pressure control device of the reactor system.
• the number of subsequent (or sequential) reaction zones is (n-1), where n is the total number of reaction zones.
• peak temperature refers to the highest temperature measured in a reaction zone. In an autoclave reaction zone (typically, noted as a maximum zone temperature), and in a tubular reaction zone (typically noted as a peak temperature).
• the Booster compressor is a device that compresses the following: a) the low pressure recycle coming from the LPS (Low Pressure Separator), and b) optionally, the recycled compressor packing leaks, each to the pressure level required at the inlet side of the Primary compressor.
• a Booster can consist of single or multiple compressor frames, and can be potentially combined with Primary compressor frame(s).
• the Primary compressor is a device that compresses the following: a) the incoming ethylene, and/or b) the low pressure recycle coming from the Booster, and/or c) the recycled compressor packing leaks, each to the pressure level required to feed the inlet side of the Hyper compressor.
• the Primary can consist of single or multiple compressor frames, and can be potentially combined with Booster compressor frame(s).
• Hyper compressor Hyper
• Secondary compressor is a device that compresses the following: a) ethylene-based components coming from the HPR (High Pressure Recycle), and/or b) ethylene-based components coming from the Primary; each to a pressure level required to feed the reactor at its inlet pressure. This compression can take place in one or multiple compression stages.
• the Hyper comprises a plunger reciprocating compressor, and can consist of single or multiple compressor frame(s). For these devices, each compression can be combined with intermediate cooling.
• make-up when used herein, in reference to an ethylene-based feed component (i.e., “make-up ethylene or make-up ethylene feed,” “make-up CTA or make-up CTA feed”), refers to reactant, provided from an external source(s), and not provided internally from a recycled source(s).
• make-up ethylene is used as "make-up ethylene” required to compensate for the ethylene consumed by the polymerization and/or lost through, for example, ethylene purge from the process and residual ethylene in the polymer.
• recycled when used herein, in reference to a reactant (i.e., “recycled ethylene or recycled ethylene feed,” “recycled CTA or recycled CTA feed”), refers to unreacted reactant separated from the polymer in the high pressure separator(s) and/or the low pressure separator(s), and returned/compressed to the reactor.
• feed refers to make-up and/or recycled components (for example, ethylene, initiator, CTA, and/or solvent) added to a reaction zone at an inlet.
• chain transfer constant and “chain transfer 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 Experimental section.
• chain transfer activity refers to the sum of molar concentration of each applied CTA component multiplied with its chain transfer constant (Cs).
• the chain transfer constant (Cs) is the ratio of reaction rates Ks/Kp, at a reference pressure (1360 atm) and a reference temperature (130°C).
• compositions claimed through use of the term “comprising” may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary.
• rheology modifier or “rheology modifying agent,” as used herein, refer to components which are able to change the rheology of the polymer, for example, increase G', when incorporated into the polymer.
• branching agent refers to components able to form H- or T-branches in Polymer, by which rheology of the polymer is modified, for example, increase of G' .
• Density - Samples for density measurement are prepared according to ASTM D 1928. Samples are pressed at 190°C and 30,000 psi for 3 minutes, and then at (21°C) and 207 MPa for one min. Measurements are made within 1 hour of sample pressing using ASTM D792, Method B. Melt Index - Melt index, or 12, was measured in accordance by ASTM D 1238, Condition 190°C/2.16 kg, and was reported in grams eluted per 10 minutes.
• the films are extracted for two hours, in a hexane vessel, containing about 1000 ml of hexane, at 49.5 + 0.5°C, in a heated water bath.
• the hexane used is an isomeric "hexanes" mixture (for example, Hexanes (Optima), Fisher Chemical, high purity mobile phase for HPLC and/or extraction solvent for GC applications).
• the films are removed, rinsed in clean hexane, and dried in a vacuum oven (80 + 5°C) at full vacuum (ISOTEMP Vacuum Oven, Model 281A, at approximately 30 inches Hg) for 2 hours.
• the films are then place in a desiccators, and allowed to cool to room temperature for a minimum of one hour.
• Rheological G' The sample is prepared from a compression molding plaque. A piece of aluminum foil is placed on a back plate, and a template or mold is placed on top of the back plate. Approx. 12 grams of resin is placed in the mold, and a second piece of aluminum foil is placed over the resin and mold. A second back plate is then placed on top of the aluminum foil. The total ensemble is put into a compression molding press, run at the following conditions: 3 min at 150°C and 10 bar, followed by 1 min at 150°C and 150 bar, followed by a "1.5 min" quench cooling to room temperature at 150 bar. A 25 mm disk is stamped out of the compression-molded plaque. The thickness of the disk is approx. 2.0 mm.
• the rheology measurement to determine G' is done in a N 2 environment, at 170°C and a strain of 10%.
• the stamped-out disk is placed between the two "25 mm" parallel plates located in an ARES-1 (Rheometrics SC) rheometer oven, which is preheated for at least 30 minutes at 170°C, and the gap of the "25 mm” parallel plates is slowly reduced to 1.65 mm.
• the sample is allowed to remain for exactly 5 mins at these conditions.
• the oven is then opened, the excess sample is carefully trimmed around the edge of the plates, and the oven is closed.
• the storage modulus (G') and loss modulus (G") are measured via a small amplitude, oscillatory shear according to a decreasing frequency sweep form 100 to 0.1 rad/s (when able to obtain a G" value lower than 500 Pa at 0.1 rad/s), or from 100 to 0.01 rad/s.
• For each frequency sweep 1- points (logarithmically spaced) per frequency decade are used.
• the data are plotted (G' (Y-axis) versus G" (X-axis)) on a log-log scale.
• the Y-axis scale covers the range from 10 to 1000 Pa, while the X-axis scale covers the range from 100 to 1000 Pa.
• the Orchestrator software is used to select the data in the region where G" is between 200 and 800 Pa (or using at least 4 data points).
• G' at G" equal to 500 Pa, is determined by interpolation.
• G' at G" 500 Pa is reported.
• nCTA i s tne "amount of moles of the jth CTA injected to the ith reactor zone," and n eth is the “amount of moles of ethylene injected to the ith reactor zone.”
• the "transfer activity of a CTA (system) in a reactor zone i" 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).
• the chain transfer activity constant (Cs) 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 Eqn. B, where ricompi is the total number of CTAs in reactor zone i,
• Equations B and C simplify to
• a polymerization simulation model with applied reaction scheme and kinetics is described by Goto et al., see references below.
• Other reactor and product modeling frameworks are available through Aspen Plus of Aspen Technology, Inc., Burlington, Massachusetts, USA; and PREDICI of Dr. Wulkow Computing in Technology GmbH (CiT), Rastede, Germany. Process and product responses predicted by these model frameworks are determined by the reactor parameters and the applied reaction scheme and kinetic parameters.
• the applied reaction scheme and kinetic parameters are described below.
• one calculation cell can be used for each well-stirred autoclave reaction zone.
• enough calculation cells are used to accurately represent the pressure, temperature and concentration profiles along the tubular reaction zone, such that the simulated product and process results, as reported in Tables 5-8, do not change with the addition of more cells.
• the polymerization simulations were achieved with Goto LDPE simulation model as described in the following: S. Goto et al; Journal of Applied Polymer Science: Applied Polymer Symposium, 36, 21-40, 1981 (Title: Computer model for commercial high pressure polyethylene reactor based on elementary reaction rates obtained experimentally).
• the kinetic data for selected CTAs are given in Table 3.
• the kinetic constants have been calculated with the help of the kinetic constants on the Cs-value (ks/kp), as determined by Mortimer and the ethylene propagation kinetics as given by Goto et al. (see Table 2).
• SCBs the backbiting mechanism generates mostly ethyl and butyl branches, while methyl branches are formed through copolymerization when propylene is used as a CTA to lower product density.
• the extractability of polymer molecules in non-polar solvents is influenced by polymer density (or in other words, by polymer melting point or SCB frequency), and molecular weight.
• a higher SCB level and lower molecular weight will promote extraction.
• the polymer formed in the last reaction zone, at peak temp. will greatly contribute to and determine the final extractable level, since it typically has the highest level of SCB combined with a low chain length, due to lower degree of polymerization (DP, the propagation rate divided by the sum of all chain termination steps excluding LCB) and the higher degree of LCB.
• DP the propagation rate divided by the sum of all chain termination steps excluding LCB
• the probability of further growth of formed small molecules by the LCB mechanism is minimal by size of the molecules and low amount of remaining polymerization.
• an average value for the minimum polymer chain segment length can be calculated.
• the minimum chain segment length listed in Table 8 shows the number of carbon atoms of the linear backbone. The length of an average SCB was assumed to be 3 carbon atoms, being the average of an ethyl and butyl branch.
• Methyl branches deriving from propylene as a CTA were treated after apphcation of the 0.75 correction factor in a similar manner.
• Ethylene stream (15) is cooled and liquids and/or solids are removed in stream (17).
• Stream (16) is a purge stream to remove impurities and/or inerts.
• the polymer separated in the LPS is further processed in (12).
• the ethylene removed (13) in the LPS is fed to the Booster, where, during the compression, condensables such as solvent, lubrication oil and others are collected and removed through stream (14).
• the outlet of the Booster is combined with make-up ethylene stream (1), and further compressed by the Primary compressors.
• pressurized water was used for cooling and/or heating the reaction medium, by circulating this water through the jacket of the reactor.
• the non-converted ethylene, and other gaseous components in the reactor outlet were recycled through the high pressure recycle and low pressure recycle, and were compressed and distributed through the booster, primary and hyper (secondary) compressor systems.
• Figure 5 shows the flow scheme of the polymerization process with a tubular reactor, used to produce Comp. Exs. 3', 4', 5', 8' and 9'.
• Stream (1) ethylene make-up, is compressed together with the outlet of the Booster by Primary compressor A and B, resulting in stream (2) and (3).
• Stream (3) is fed together with additional ethylene from the high pressure recycle stream (19) through line (5) to the Hyper compressor part feeding the front (9) of the Reactor.
• Stream (2) is combined with the high pressure recycle stream (17) resulting in stream (18).
• the Hyper compressor part feeding the side stream (8) receives ethylene feed through line (18) and (4).
• the ethylene supplied by line (8) is distributed through line (20) and (21) to the side of the reactor.
• Liquid CTAs can be added via Stream (6) and/or Stream (7).
• Stream (2) is combined with high pressure recycle stream (18), and distributed over flow (4) and flow (19).
• the Hyper compressor part feeding the front (9) of the reactor receives from line (18) ethylene feed through line (19) and line (5).
• the Hyper compressor part feeding the side stream (8) receives ethylene feed through line (4).
• the ethylene supplied by line (8) is distributed through line (20) and (21) to the side of the reactor.
• Line (4) receives ethylene feed from line (3) and additional ethylene from line (18).
• the Hyper pressurizes the ethylene feed streams to a level sufficient to feed the high pressure tubular reactor (Reactor). After finishing the reaction, and having applied multiple cooling steps, the reaction mixture is depressurized and/or cooled in (10), and separated as discussed above.
• FIG. 4 shows the flow scheme of the high pressure polymerization with a tubular reactor, used to produce Comp. Exs. 7' and 12'.
• Stream (1) ethylene make-up, is compressed together with the outlet of the Booster by Primary compressor system resulting in flow (3).
• Stream (3) is combined with high pressure recycle stream (19) and fed through line 5 to the Hyper compressor part feeding the front (9) of the Reactor.
• the Hyper compressor part feeding the side stream (8) receives ethylene feed through line (4).
• the ethylene supplied by line (8) is distributed through line (20) and (21) to the side of the reactor.
• Line (4) receives ethylene feed from line (18).
• the CTA is fed through line (6) and/or (7) or line (22).
• the Hyper pressurizes the ethylene feed streams to a level sufficient to feed the high pressure tubular reactor (Reactor). After finishing the reaction, and having applied multiple cooling steps, the reaction mixture is depressurized and/or cooled in (10), and separated as discussed above.
• each polymerization was carried out in tubular reactor with three reaction zones.
• pressurized water was used for cooling and/or heating the reaction medium, by circulating this water through the jacket of the reactor.
• Organic peroxides (see Table 4) were fed into each reaction zone.
• pressurized water was used for cooling and/or heating the reaction medium, by circulating this water through the jacket of the reactor.
• Each reaction zone had one inlet and one outlet. Each inlet stream consisted of the outlet stream from the previous reaction zone and/or an added ethylene-rich feed stream. After reaching the first peak temperature in reaction zone 1, the reaction medium was cooled down with pressurized water.
• the reaction medium was further cooled by injecting a cold ethylene-rich feed stream (#20), and the reaction was initiated again, by feeding an organic peroxide system into the reaction zone. This process was repeated at the end of the second reaction zone, to enable further polymerization in the third reaction zone.
• the non-converted ethylene, and other gaseous components in the reactor outlet were recycled through a high pressure recycle and a low pressure recycle, and were compressed and distributed through the booster, primary and hyper (secondary) compressor systems.
• the polymer was extruded and pelletized (about 30 pellets per gram), using a single screw extruder.
• the polymer was extruded and pelletized (about 30 pellets per gram), using a single screw extruder system, at a melt temperature around 230-250°C.
• the weight ratio of the ethylene-rich feed streams to the three reaction zones was 1.00:0.76:0.24.
• the internal process velocity was approximately 12.5, 9 and 11 m/sec for respectively the 1 st , 2 nd and 3 rd reaction zones. Additional information can be found in Tables 5 and 6.
• Comp. Ex. 5' - Propylene was used as the CTA. The propylene was added to the suction of Primary A and not via stream 5 and 6.
• Comp. Ex. 9' - No TRIGONOXTM 301 was used, and propionaldehyde was the CTA. See also Tables 5- 8.
• the polymer was extruded and pelletized (about 30 pellets per gram), using a single screw extruder, at a melt temp, around 230-250°C.
• the weight ratio of the ethylene-rich feed streams to the three reaction zones was 1.00:0.80:0.20.
• the internal process velocity was approximately 12.5, 9 and 11 m/sec for respectively the 1 st , 2 nd and 3 rd reaction zones.
• Comp. Ex. 10' - Propionaldehyde was the CTA and added via stream #7.
• Comp. Ex. 11' - Isobutane was the CTA and added via stream #22.
• the comparative examples were made at varying densities, melt indices, G' and hexane extractables. These comparative examples were used to derive correlations for G', density and hexane-extractables.
• the inventive examples have even lower hexane-extractable levels.
• Empirical models are derived, valid for polymers of the type defined here, based on key outputs from the process simulations and based on measured polymer properties.
• the models are derived with linear regression using commercial software JMPOPRO version 11.1.1.
• the density calculated by Eqn. G is representative of the actual measured density in the respective polymer sample.
• this model has a correlation coefficient R 2 of 0.979.
• the predicted density is given in Table 7 for all samples, including those samples where measured density is available.
• the G' value calculated by Eqn. H is representative of the actual measured G' value in the respective polymer sample.
• this model (in the log G' form) has a correlation coefficient R 2 of 0.986.
• the hexane extractable level calculated by Equation I is representative of the actual measured hexane level in the respective polymer sample. Based on the samples CE3'-CE12', this model has a correlation coefficient R 2 of 0.862.
• the predicted hexane extractable - see Table 8 for all samples, including those samples where measured hexane extractable is available. The model is based on simulation results in the last process zone.
• Apparent hexane extractable for each reactor zone i is provided by applying the same eqn. with the same inputs, but now selected in that same reactor zone i.
• Apparent Hexane extractable (zone k) -1.65 + (0.1989 * Maximum SCB level in Rx-zone k) - (0.0486 * Minimum Chain segment length in Rx-zone k) (Eqn. J).
• the reaction mixture is depressurized and/or cooled in (10), and separated as discussed above.
• the notation "50/50/0/0” means that 50% of the total ethylene feed is fed to the first reaction zone and 50% of the total ethylene feed is fed to the second reaction zone, while no feed streams are fed to the third and fourth reaction zones.
• the ethylene received in the second, third and fourth reaction zones are carry-over from the previous reaction zones.
• the notation "50/38/12” means that 50% of the total ethylene feed is fed to the first reaction zones, 38% of the total ethylene feed is fed to the second reaction zone and 12% of the total ethylene feed is fed to the third reaction zone.
• Further Table 5 give information on pressure level and initiation temperatures of all reaction zones, the ethylene feed temperature when a side ethylene feed stream is applied, and the maximum or peak temperatures in each reaction zone (Rx).
• the ethylene feed temperature can be optionally lowered and/or controlled with a cooler.
• the temperature of the cooling media is typically in the range of 0 to 220°C, while the temperature for preheating services is typically in the range of 100 to 250°C.
• the cooling/heating is applied through jackets around the high pressure tubes by co- current or counter-current flow. In the simulations the cooling/preheating was applied by counter-current and with one cooling section per reaction zone.
• Comp. Exs. 1 and 2 The polymerization simulations for Comp. Exs. 1 and 2 are based on Comp. Ex. A and Inv. Ex. 2 of the patent application EP2681250-B1.
• CTA propionaldehyde was used.
• the reactor inlet pressure was 2800 bar.
• Comp. Ex. A is made in a tubular reactor with 4 reaction zones, and all reactants, except initiators, are fed to the front, resulting in an even CTA distribution, resulting in a product with high density and low hexane extractables and low G' -value.
• Inv. Ex. 2 is made with Zl/Zi ratio of 0, which gives a much higher G' -value.
• the Zl/Zi ratio of 0 is achieved by dividing the 1 st reaction of Comp. Ex. A in two.
• the first part is receiving only make-up ethylene containing no CTA.
• the second part is receiving the ethylene from the high-pressure and low pressure recycle also containing recycled CTA and the make-up flow of CTA.
• Inv. Ex. 1 is made at the process conditions described in Tables 5 and 6 and according to Figure 1. Propionaldehyde is used as CTA.
• the initiator system was: Rx-zone 1 (TBPiv/TBPO/DTBP/TRIGONOX 1M 301), Rx-zone 2 (TBPO/DTBP) and Rx-zone 3 (DTBP). See Tables 7 and 8. Inv. Exs. 2 to 5 are made at the conditions described in Tables 5 and 6 and according to Figure 1. Propionaldehyde is used as CTA.
• the initiator system was: Rx-zone 1 (TBPO/DTBP/ TRIGONOXTM 301), Rx-zone 2 (TBPO/DTBP/ TRIGONOXTM 301), Rx-zone 3 (DTBP) and Rx-zone 4 (DTBP.
• the main differences are MI and ethylene side stream temperature, which results in different predicted product properties see Tables 7 and 8.
• Inv. Exs. 6 to 10, 12 and 13 and Comp. Ex 13 are made at the conditions described in Tables 5 and 6 and according to Figure 2.
• Propionaldehyde is used as CTA.
• the initiator system was: Rx-zone 1 (TBPO/DTBP), Rx- zone 2 (TBPO/DTBP), Rx-zone 3 (TBPO/DTBP), Rx-zone 4 (DTBP), Rx-zone 5 (DTBP).
• the main differences are MI and ethylene side stream temperature, which results in different predicted product properties see Tables 7 and 8.
• Inv. Ex. 11 is made at the conditions described in Tables 5 and 6 and according to Figure 2.
• Propionaldehyde is used as CTA.
• the initiator system was: Rx-zone 1 (TBPO/DTBP/TRIGONOXTM 301), Rx-zone 2 (TBPO/DTBP/ TRIGONOXTM 301), Rx-zone 3 (TBPO/DTBP), Rx-zone 4 (DTBP), Rx-zone 5 (DTBP).
• Rx-zone 1 TBPO/DTBP/TRIGONOXTM 301
• Rx-zone 2 TBPO/DTBP/ TRIGONOXTM 301
• Rx-zone 3 TBPO/DTBP
• DTBP Rx-zone 4
• DTBP Rx-zone 5
• Summary of Simulated Polymerization of Study 2 - Comp. Ex. 1 shows a high density and low hexane extractable, but also a very low G' value.
• Comp. Ex. 2 has a good G' value and hexane extractable level, but too high a density.
• the low hexane extractable-level is achieved, by applying low peak-temperatures in the last reaction zone(s).
• the desired densities are achieved by applying the correct combination of CTA-system, peak temperatures and reactor pressure.
• Comp. Exs. 3 to 12 are actual polymerizations, and are used to derive the correlations for density, G' and hexane extractables as described above.
• Comp. Ex. 13 has a high G' value at relevant density, but too high hexane extractable level, due to high peak temperatures.
• Table 9 lists tubular products together and some autoclave extrusion products. Autoclave resins have low hexane extractables due to the lower maximum polymerization temperatures.
• **170°C data is interpolated from 150°C and 190°C data.

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