Ethylene polymer composition having branches

Abstract

The present disclosure provides ethylene-based polymers formed from reacting ethylene monomer with bisallyl maleate ("BAIIM") under polymerization conditions. The ethylene-based polymers of the present invention having ethylene monomer and bisallyl maleate branching agent are interchangeably referred to as "BAIIM-PE."

Description

Technical Field

[0001] The level of branching in ethylene polymers, such as low density polyethylene (LDPE), is mainly due to, for example, the reactor design (autoclave or tubular) and the polymerization conditions used to make LDPE. Branching agents for improving the level of branching in LDPE are known. However, the process conditions required to achieve modified LDPE with a high level of branching often result in a final product with a lower crystallinity and a higher content of low molecular weight extractable fractions.

[0002] Accordingly, there is a continuing need in the art for LDPE having improved melt strength for an improved level of branching and for LDPE prepared under polymerization conditions that maintain good polymer properties.

Summary of the Invention

[0003] The present disclosure provides an ethylene polymer. The ethylene polymer is formed by reacting (under polymerization conditions) an ethylene monomer with (i) Diallyl maleate, (ii) diallyl fumarate, or (iii) a mixture of diallyl maleate and diallyl fumarate (individually and collectively hereinafter referred to as "BAIIM") and. The ethylene polymer of the present invention having an ethylene monomer and BAIIM a branching agent is interchangeably referred to as "BAIIM-PE".

[0004] The present disclosure also provides a process for manufacturing an ethylene polymer composition of the present invention. The process includes polymerizing an ethylene monomer in the presence of BAIIM under polymerization conditions and forming an ethylene polymer (BAIIM-PE).

[0005] Definitions Any reference to the Periodic Table of the Elements is as it was issued by CRC Press, Inc. in 1990 - 1991. References to the groups of elements in this table are by the new notation for group numbering.

[0006] For purposes of U.S. patent practice, the content of any referenced patent, patent application, or publication is hereby incorporated by reference in its entirety (or its equivalent U.S. version is so incorporated by reference) with respect to definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure), and general knowledge in the relevant art.

[0007] The numerical ranges disclosed herein include all values from the lower value to the upper value, including the upper and lower values. For ranges containing explicit values (e.g., 1 or 2, or 3 to 5, or 6, or 7), any sub-ranges between any two of the explicit values (e.g., in the range of 1 to 7 above, sub-ranges such as 1 to 2, 2 to 6, 5 to 7, 3 to 7, 5 to 6, etc.) are included.

[0008] Unless otherwise indicated, not implied from the context, or not customary in the relevant art, all parts and percentages are by weight, and all test methods are the latest as of the filing date of this disclosure.

[0009] As used herein, the terms "blend" or "polymer blend" refer to a mixture of two or more polymers. The blend may or may not be miscible (not phase-separated at the molecular level). The blend may or may not be phase-separated. The blend may or may not contain one or more domain configurations as determined from transmission electron spectroscopy, light scattering, X-ray scattering, and other methods known in the art. The blend can be achieved by physically mixing two or more polymers at the macro level (e.g., melt blend resin or compounding) or at the micro level (e.g., co-molding in the same reactor).

[0010] The term "composition" refers to a mixture of materials that includes the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0011] The terms "comprising", "including", "having", and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether or not the same are specifically disclosed. To avoid doubt, all compositions claimed through the use of the term "comprising" may include any additional additives, adjuvants, or compounds, whether polymeric or not, unless the contrary is stated. In contrast, the term "consisting essentially of" excludes from the scope of any subsequent description any other components, steps, or procedures, except for those that are not essential to the operability. The term "consisting of" also excludes any components, steps, or procedures not specifically depicted or enumerated. The term "or" refers to the listed members individually as well as in any combination, unless otherwise specified. The use of the singular form includes the use of the plural form and vice versa.

[0012] As used herein, the term "ethylene / alpha-olefin copolymer" refers to a copolymer having more than 50 mole percent polymerized ethylene monomer (based on the total amount of polymerizable monomers) and at least one alpha-olefin.

[0013] As used herein, the term "ethylene-based polymer composition" refers to a composition that, in polymeric form, contains more than 50 weight percent, or a majority amount, of ethylene, based on the weight of the polymer, and optionally may contain at least one comonomer or other molecule.

[0014] As used herein, the term "ethylene monomer" refers to a chemical unit having two carbon atoms with a double bond therebetween and each carbon bonded to two hydrogen atoms, and the chemical unit polymerizes with other such chemical units to form an ethylene-based polymer composition.

[0015] As used herein, the term "high density polyethylene" (or HDPE) refers to an ethylene polymer having a density of at least 0.94 g / cc, or at least 0.94 g / cc to 0.98 g / cc. HDPE has a melt index of 0.1 g / 10 min to 25 g / 10 min. HDPE can include ethylene and one or more C3-C 20 α-olefin comonomers. The comonomer can be linear or branched. Non-limiting examples of suitable comonomers include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. HDPE can be prepared using any of a Ziegler-Natta catalyst, a chromium-based catalyst, a geometrically constrained catalyst, or a metallocene catalyst in a slurry reactor, a gas phase reactor, or a solution reactor. Ethylene / C3-C 20 α-olefin comonomers include at least 50 weight percent, or at least 70 weight percent, or at least 80 weight percent, or at least 85 weight percent, or at least 90 weight percent, or at least 95 weight percent of ethylene in polymerized form.

[0016] As used herein, the term "low density polyethylene" (or LDPE) refers to polyethylene having a density of from 0.910 g / cc to less than 0.940 g / cc, or from 0.918 g / cc to 0.930 g / cc, and a broad molecular weight distribution (MWD), i.e., a "broad MWD" of 4.0 to 20.0, with long chain branching.

[0017] As used herein, the terms "polymer" or "polymeric material" refer to compounds prepared by polymerizing monomers, whether of the same type or different types, and provide the multiple and / or repeating "units" or "mer units" that make up the polymer in polymerized form. Thus, the general term "polymer" encompasses the term "homopolymer" and is commonly used to refer to a polymer prepared from only one type of monomer, and the term "copolymer" is commonly used to refer to a polymer prepared from at least two types of monomers. It also includes all forms of copolymers, such as random, block, etc. The terms "ethylene / α-olefin polymer" and "propylene / α-olefin polymer" each refer to the above-described copolymers prepared by polymerizing ethylene or propylene with one or more additional polymerizable α-olefin monomers. Polymers are often said to be "made of" one or more specific monomers, "based on" a specific monomer or monomer type, "containing" a specific monomer content, etc., but in this context, it should be noted that the term "monomer" is understood to refer to the polymerized residue of a specific monomer and not to non-polymerized species. Generally, polymers herein refer to those based on "units" that are the polymerized form of the corresponding monomers.

[0018] Test Methods Density is measured in accordance with ASTM D792, Method B. Results are reported in grams per cubic centimeter (g / cc).

[0019] Infrared Spectroscopy (IR). Calibration of the IR5 detector ratio is from a homopolymer (0 SCB / 1000 total C) to a known short chain branch (SCB) frequency in the range of approximately 50 SCB / 1000 total C (where total C = carbon in the main chain + carbon in the branches) 13Performed using at least 10 ethylene polymer standards (polyethylene homopolymers and ethylene / octene copolymers) measured by 13C NMR method. Each standard had a weight average molecular weight of 36,000 g / mol to 126,000 g / mol as determined by GPC-LALLS. Each standard had a molecular weight distribution (Mw / Mn) of 2.0 to 2.5 as determined by GPC. Examples of the polymer properties of the copolymer standards are shown in Table A.

Table 1

[0020] The "IR5 area ratio (or "IR5 メチルチャネル面積 / IR5 測定チャネル面積 ")" of "area response minus the baseline of the IR5 methyl channel sensor" vs. "area response minus the baseline of the IR5 measurement channel sensor" (standard filters and filter wheels supplied by PolymerChar: Part Number IR5_FWM01 are included as part of the GPC-IR instrument) was calculated for each of the "copolymer" standards. A linear fit of weight % comonomer frequency vs. "IR5 area ratio" was constructed in the form of Equation 1 below. Weight % comonomer = A0 + [A1 × (IR5 メチルチャネル面積 / IR5 測定チャネル面積 )] (Equation 1)

[0021] If there is significant spectral overlap between the comonomer end (methyl) and the determined molecular weight at each chromatographic slice, end-group correction of the comonomer weight % data can be performed using knowledge of the end mechanism.

[0022] Melt index As used herein, the term "melt index" refers to a measure of how easily a thermoplastic polymer flows when in a molten state. The melt index, or I2, is measured according to ASTM D1238, Condition 190°C / 2.16 kg and reported in grams eluted per 10 minutes (g / 10 min). I10 is measured according to ASTM D1238, Condition 190°C / 10 kg and reported in grams eluted per 10 minutes (g / 10 min). The melt index ratio (I 10 / I2) is measured according to ASTM D1238 by taking the ratio of the values obtained at 10 kg and 2.16 kg at a temperature of 190°C.

[0023] Melt Strength As used herein, the term "melt strength" refers to a measure of the maximum tensile force applied to a polymer in a molten state before the polymer breaks. Melt strength is measured at 190°C using a Goettfert Rheotens 71.97 (Goettfert Inc., Rock Hill, SC). A Goettfert Rheotester 2000 capillary rheometer with a flat entry angle (180 degrees), 30 mm in length and 2 mm in diameter is supplied to the molten sample (25 - 50 grams). The sample is supplied to the barrel (L = 300 mm, diameter = 12 mm), compressed, and allowed to melt for 10 minutes, after which it is extruded at a constant piston speed of 0.265 mm / s (which corresponds to a wall shear rate of 38.2 s -1 for a given die diameter). The extrudate passes through a rheotens wheel located 100 mm below the die exit and is pulled downward by the wheel at an acceleration rate of 2.4 millimeters per square second (mm / s 2 ). The force applied to the wheel (measured in centinewtons, cN) is recorded as a function of the speed of the wheel (mm / s). The sample is repeated at least twice until two curves of force (cN) as a function of strand speed (mm / s) overlap. The curve showing the highest speed at strand break is then reported. Melt strength is reported in units of centinewtons (cN) as the plateau force before the strand is cut.

[0024] Nuclear magnetic resonance ( 1 H NMR) As used herein, the terms "nuclear magnetic resonance" or "NMR" refer to the spectral analysis of a material or compound that provides information regarding the chemical composition and structure of the material or compound. Samples for proton NMR were prepared using 0.1 - 0.2 g of the sample in 3.25 g of 30 / 70 weight / weight o-dichlorobenzene-d4 / perchloroethylene (ODCB-d4 / PCE) containing 0.001 M chromium(III) acetylacetonate, Cr(AcAc)3, prepared in a 10 mm tube. The samples were heated at 115 °C and vortexed to ensure homogeneity. Single pulse proton spectra were acquired on a Bruker high temperature CryoProbe and a Bruker AVANCE 600 MHz spectrometer with a sample temperature of 120 °C. Spectra were acquired with a ZG pulse P1 = 20 us (90° PW), 64 scans, AQ 1.82 seconds, D1 15 seconds.

[0025] Gas chromatography analysis As used herein, the term "gas chromatography analysis" refers to a method for separating the components of a chemical mixture by weight.

[0026] Water extraction and preparation for headspace - solid phase microextraction (HS - SPME) Sample films were prepared. Each 2 gram (approx. 1 inch x 1 inch) sample (approx. 1.3 mil polymer coated on a release liner and removed to function as a free - standing film) was weighed into individual "20 mL" headspace vials, and the vials were sealed. The vials with the films were equilibrated at 75 °C for 10 minutes, and the headspace was extracted by SPME for analysis by gas chromatography using a quadrupole mass spectrometer (GC / qMS).

[0027] Preparation of HS - SPME Each film (10 grams, approximately 1 inch x 1 inch) was weighed into a "40 mL" glass bottle (I-Chem, high purity). The vial was completely filled with high purity water (ASTM type I, reagent grade, Mill-Q Integral 3, 18.2 MΩ, <5 ppb TOC). The vial was sealed with a PTFE-lined cap and the film was extracted at 40 °C for 48 hours. After 48 hours, the bottle was removed from the oven and the contents were allowed to return to room temperature (approximately 4 hours). HS-SPME analysis was performed using a 20 mL headspace vial. Each vial was prepared with "3.5 g" of sodium sulfate (Sigma-Aldrich, ACS reagent grade, purified by heating in a furnace at 1050 °F for 12 hours) and 10 grams of water extract (without film). The mixture was vigorously mixed and sonicated for 15 minutes to dissolve the sodium sulfate. The vial was then equilibrated at 75 °C for 10 minutes and the headspace was extracted by SPME for analysis by gas chromatography using a quadrupole mass spectrometer (GC / qMS).

[0028] GC / ODP / qMS analysis conditions The headspace within each vial was sampled by SPME and analyzed by GC / qMS. Quantification was performed using an external standard calibration procedure. Automated sample analysis was performed using a Gerstel Multipurpose Sampler (MPS), an Agilent 7890A gas chromatography, and an Agilent 5975C inert XL quadrupole mass spectrometer. The MPS was controlled using Gerstel's Maestro software. The control and data collection of GC / qMS were performed using Agilent's Chemstation software. The headspace of the water extract was equilibrated with water at 75 °C for 10 minutes with stirring and sampled using a "2 cm × 50 / 30 μm" di-alkene benzene / carboxen / polydimethylsiloxane (Supleco) SPME fiber. The components of the SPME fiber were desorbed at a split / splitless inlet at 250 °C and subsequently separated using an Agilent, VF-WAXms, "30 m × 250 μm × 0.5 μm" capillary column with an oven temperature program of 50 °C (held for 2 minutes) to 260 °C (held for 6 minutes), at 15 °C / min, and an initial column flow of helium at 2.0 mL / min.

[0029] The samples were then comparatively ranked on a scale of 1 to 5 (where 1 indicates the minimum and 5 indicates the maximum) for the oxygenated species (OS) or total volatile organic compounds (VOC) detected within the materials.

[0030] GPC method: Triple detector gel permeation chromatography (TDGPC) for PE A triple detector gel permeation chromatography (3D-GPC or TDGPC) system consisting of a Polymer Laboratories (now Agilent) high temperature chromatograph Model 220 equipped with a 2-angle laser light scattering (LS) detector Model 2040 (Precision Detectors, now Agilent), an IR-5 infrared detector from Polymer Char (Valencia, Spain), and a 4-capillary solution viscometer (DP) (Visotek, now Malvern) is used. Data collection is performed using a Polymer Char DM100 data acquisition box and related software (Valencia, Spain). This system is also equipped with an online solvent degassing device from Polymer Laboratories (now Agilent). A high temperature GPC column consisting of four 30 cm, 20 μm mixed A LS columns from Polymer Laboratories (now Agilent) is used. The sample carousel compartment is operated at 140 °C and the column compartment is operated at 150 °C. Samples are prepared at a concentration of 0.1 gram of polymer in 50 milliliters of solvent. The chromatography solvent and sample preparation solvent is 1,2,4-trichlorobenzene (TCB) containing "200 ppm of 2,6-di-tert-butyl-4-methylphenol (BHT)". The solvent is sparged with nitrogen. The polymer sample is gently stirred at 160 °C for 4 hours. The injection volume is 200 microliters. The flow rate through the GPC is set at 1.0 ml / min. Column calibration and sample molecular weight calculations are performed using Polymer Char "GPC One" software. The GPC column is calibrated using 21 narrow molecular weight distribution polystyrene standards. The molecular weights of the polystyrene standards range from 580 to 8,400,000 g / mol and are placed in six "cocktail" mixtures with at least one order of magnitude spacing between individual molecular weights. The peak molecular weight of the polystyrene standard is converted to polyethylene molecular weight using the following equation (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)): M ポリエチレン =A(Mポリエチレン ) B , where B has a value of 1.0, and the experimentally determined value of A is about 0.38 to 0.44. By fitting a first-order polynomial to the calibration points corresponding to each polyethylene obtained from the above formula, a column calibration curve for the observed elution volume is obtained. The conventional number and weight average molecular weights (Mn(conventional) and Mw(conventional), respectively) are calculated according to the following formula,

Number

Number

Number

Number

Number

Number

[0031] Column: Agilent PLgel 5μm particle size column (4 columns in 1 set, pore sizes 50, 100, 1000, 10000 Å), Column temperature: 40 °C, Eluent: Tetrahydrofuran (THF), unstabilized, Flow rate: 1.0 mL / min, Injection volume: 100 μL, Analysis time: 45 minutes, Sample concentration: 2.5 mg / mL, Detector: Viscoteck TDA 305 using a refractive index detector, Detector temperature: 40 °C, Calibration: Agilent Technologies' polystyrene (PS) EasiCal PS-2, batch number 0006252842, and Software: OmniSEC 4.7.0.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

DETAILED DESCRIPTION OF THE INVENTION

[0033] 1. Polymer The present disclosure provides an ethylene polymer. The ethylene polymer is formed by reacting (under polymerization conditions) an ethylene monomer with BAIIM and. The ethylene polymer is a polymerization reaction product of ethylene and BAIIM and. BAIIM is (i) Diallyl maleate, (ii) diallyl fumarate, or (iii) a mixture of diallyl maleate and diallyl fumarate It is understood that it can be. Diallyl maleate (Or “BAIIM”) has Structure I:

CHEMICAL FORMULA

[0034] Without being bound by a particular theory, BAIIM is a branching agent that improves the melt strength of the formant ethylene polymer. Under polymerization conditions, one, two, or all three carbon-carbon double bonds in Structure I react (bond) with the growing chains that form the ethylene polymer to become part of the polyethylene chains. The ethylene polymer of the present invention having an ethylene monomer and BAIIM a branching agent is interchangeably referred to as “BAIIM-PE”.

[0035] In one embodiment, BAIIM is A mixture containing diallyl maleate and diallyl fumarate is. In a further embodiment, BAIIM is BAIIM mixtureBased on the total weight, the majority amount (more than 50% by weight) of A mixture containing the weight percentages of diallyl maleate and a small amount of diallyl fumarate is as follows.

[0036] In one embodiment, BAIIM-PE, in the polymerized form, contains 95% by weight, or 96% by weight, or 97% by weight, or 98% to 99% by weight, or 99.5% by weight, or 99.8% by weight, or 99.9% by weight, or 99.95% by weight, or 99.99% by weight of ethylene and a corresponding amount (reciprocal amount) of BAIIM, or 5.0% by weight, or 4.0% by weight, or 3.0% by weight, or 2.0% to 1.0% by weight, or 0.5% by weight, or 0.2% by weight, or 0.1% by weight, or 0.05% by weight, or 0.01% by weight of BAIIM. The weight percentages are based on the total weight of BAIIM-PE. In a further embodiment, BAIIM-PE, in the polymerized form, contains 95% to 99.99% by weight, or 96% to 99.95% by weight, or 97% to 99.9% by weight, or 98% to 99.8% by weight of ethylene, and BAIIM is present in an amount of 5.0% to 0.01% by weight, or 4.0% to 0.05% by weight, or 3.0% to 0.1% by weight, 2.0% to 0.2% by weight.

[0037] In an embodiment, BAIIM-PE has 1 H NMR peaks at about 3.41 ppm and about 3.8 ppm. In a further embodiment, BAIIM-PE has 1 H NMR peaks at about 3.41 ppm and about 3.8 ppm, and there are no peaks between the 3.41 ppm peak and the 3.8 ppm peak. Without being bound by a particular theory, the peaks at about 3.41 ppm and about 3.8 ppm are thought to be due to the allyl CH2-O- of BAIIM after BAIIM is incorporated into the ethylene-based polymer of the present invention, and thus, this is R,R’-CH2-O-. The peaks at about 3.41 ppm and about 3.8 ppm indicate the incorporation of BAllM into the polyethylene chain, leading to an improvement in the melt strength of BAIIM-PE. The 1The 1H NMR spectrum is shown in Figure 1.

[0038] In one embodiment, the 1H NMR peak at about 3.41 ppm 1 has an area that is at least three times larger than the area of the 1H NMR peak at about 3.8 ppm for BAIIM-PE. 1 In a further embodiment, the 1H NMR peak at about 3.41 ppm 1 has an area that is three times, or four to six times, or seven times larger than the area of the 1H NMR peak at about 3.8 ppm.

[0039] In one embodiment, BAIIM-PE exhibits two carbonyl peaks in the infrared spectrum, a first carbonyl peak centered at 1737 cm-1 and a second carbonyl peak centered at 1785 cm-1. Without being bound by a particular theory, the peak at 1737 cm-1 is thought to be due to the presence of a saturated ester functional group, and the peak at 1785 cm-1 is thought to be due to the presence of a carbonyl stretching vibration in a lactone.

[0040] BAIIM-PE has a density of 0.916 g / cc to 0.930 g / cc.

[0041] In one embodiment, BAIIM-PE has a melt index (I2) of 0.15 g / 10 min, or 0.5 g / 10 min, or 1.0 g / 10 min, or 5.0 g / 10 min, or 10 g / 10 min, or 20 g / 10 min, or 30 g / 10 min, or 40 g / 10 min to 50 g / 10 min, or 60 g / 10 min, or 70 g / 10 min, or 80 g / 10 min. In a further embodiment, BAIIM-PE has a melt index (I2) of 0.15 g / 10 min to 80 g / 10 min, or 0.5 g / 10 min to 70 g / 10 min, or 1.0 g / 10 min to 60 g / 10 min, or 5.0 g / 10 min to 50 g / 10 min, or 10 g / 10 min to 40 g / 10 min, or 20 g / 10 min to 30 g / 10 min.

[0042] In one embodiment, BAIIM-PE contains 0.021 wt% to 0.063 wt% BAIIM (based on the total weight of BAIIM-PE) and has 1 H NMR peaks at about 3.41 ppm and about 3.8 ppm and IR peaks at 1737 cm-1 and 1785 cm-1, and BAIIM-PE has a melt index of 0.15 g / 10 min to 80 g / 10 min.

[0043] BAIIM-PE can include combinations of two or more embodiments as described herein.

[0044] The present disclosure also provides an article comprising at least one component formed from the BAIIM-PE described herein.

[0045] In one embodiment, the article is a coating of a film.

[0046] In one embodiment, the article is a coating.

[0047] In one embodiment, the article is a film.

[0048] The article can include combinations of two or more embodiments as described herein.

[0049] 2. Process The present disclosure also provides a process for producing the ethylene polymer composition of the present invention. The process includes polymerizing an ethylene monomer in the presence of BAIIM and forming an ethylene polymer (also interchangeably referred to as "BAIIM-PE"). As used herein, the term "polymerization conditions" includes free radical-initiated polymerization in a polymerization reactor under high pressure (11,000 psig to 53,000 psig) and high temperature (200 °C to 350 °C).

[0050] The polymerization conditions include polymerization using one, two, or more free radical indicators. Non-limiting examples of suitable free radical initiators include organic peroxides, cyclic peroxides, diacyl peroxides, dialkyl peroxides, hydroperoxides, peroxyesters, peroxyketals, t-butyl peroxypivalate, di-t-butyl peroxide, t-butyl peroxyacetate, t-butyl peroxyethylhexanoate, and t-butyl peroxy-2-hexanoate, and combinations thereof. In one embodiment, these organic peroxide initiators are used in an amount of 0.001 wt% to 0.2 wt% based on the weight of the polymerizable monomer.

[0051] In a further embodiment, the free radical initiator comprises at least one peroxide group incorporated into a ring structure. Examples of such initiators include TRIGONOX 301 (3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonan) and TRIGONOX 311 (3,3,5,7,7-pentamethyl-1,2,4-trioxepane), both of which are available from Akzo Nobel, and HMCH-4-AL (3,3,6,6,9,9-hexamethyl-1,2,4,5-tetroxonan) available from United Initiators, but are not limited thereto.

[0052] Regarding the polymerization conditions, the polymerization reactor includes a reactor configuration including a tubular reactor, and / or an autoclave reactor, and / or a continuous stirred tank reactor.

[0053] In one embodiment, the polymerization is carried out in a reactor configuration including at least one tubular reactor.

[0054] In one embodiment, the polymerization is carried out in a reactor configuration including at least one autoclave reactor.

[0055] In one embodiment, the process reacts ethylene based on the amount of ethylene added to the reactor at 30 mole ppm (0.021 wt%) to 90 mole ppm (0.063 wt%) of BAIIM and forms an ethylene-based polymer having a melt strength greater than 15 cN to 20 cN. As used herein, the term "mole ppm" is 1×10 -6 moles of ethylene relative to 1 mole of BAIIM.

[0056] In one embodiment, a conventional chain transfer agent (CTA) is used to control the molecular weight. During the polymerization process, one or more CTAs are added. Non-limiting examples of CTAs include propylene, isobutane, n-butane, 1-butene, methyl ethyl ketone, acetone, ethyl acetate, propionaldehyde, ISOPAR (ExxonMobil Chemical Co.), methanol, and isopropanol. In one embodiment, the amount of CTA used in the process is from 0.03 weight percent to 10 weight percent of the total reaction mixture.

[0057] In one embodiment, the process includes a process recycle loop to improve conversion efficiency.

[0058] In one embodiment, the polymerization is carried out in a tubular reactor. The tubular reactor can be a single-zone tubular reactor or a multi-zone tubular reactor. In a further embodiment, the tubular reaction is a multi-zone tubular reactor. The multi-zone tubular reactor includes alternative locations for supplying fresh ethylene to control the ratio of ethylene to CTA and thus control the polymer properties. Fresh ethylene monomer is added simultaneously at multiple locations to achieve the desired ratio of ethylene monomer to chain transfer. Similarly, to control the polymer properties, the addition of fresh CTA addition points is selected. Fresh CTA is added simultaneously at multiple locations to achieve the desired ratio of CTA to ethylene monomer. Likewise, the addition points and the amount of fresh BAIIM are controlled to control gel formation while maximizing the desired properties of improved melt strength and performance in the intended application. Fresh BAIIM is added simultaneously at multiple locations to achieve the desired ratio of branching agent to ethylene monomer. The use of BAIIM to broaden the molecular weight distribution and improve the melt strength of the polymer is accompanied by or minimizes potential adverse effects such as gel formation, reactor fouling, and process instability, and additional requirements are imposed on the distribution of CTA and BAIIM along the reactor system to achieve the desired changes in the product properties while minimizing the amount of BAIIM. Non-limiting examples of suitable multi-zone tubular reactors are described in WO2013 / 059042 and WO2013 / 078018, the contents of each reference being incorporated herein by reference.

[0059] In one embodiment, the polymerization is carried out in a multi-reactor system where an autoclave reactor precedes the tubular reactor. The addition points and amounts of fresh ethylene, fresh CTA, and fresh BAIIM are controlled to achieve the desired ratios of CTA to ethylene monomer and BAIIM to ethylene monomer in the feed to the reaction zone and / or in the reaction zone.

[0060] In one embodiment, BAIIMis fed directly to the reaction zone via the compression stage or directly to the feed to the reaction zone. The choice of the point of reaction and / or feed to the reaction zone depends on several factors including, but not limited to, the solubility of BAIIM in pressurized ethylene and / or the solvent, the condensation of BAIIM in pressurized ethylene, and / or fouling due to premature polymerization of BAIIM in the preheater used to heat the contents of the reactor prior to injection of the initiator.

[0061] In one embodiment, BAIIM is fed directly to the reaction zone or directly to the feed to the reaction zone.

[0062] In one embodiment, the branching agent is fed only to reaction zone 1.

[0063] In one embodiment, the ethylene fed to the first reaction zone is 10 percent to 100 percent of the total ethylene fed to the polymerization. In further embodiments, the ethylene fed to the first reaction zone is 20 percent to 80 percent, further 25 percent to 75 percent, further 30 percent to 70 percent, and further 40 percent to 60 percent of the total ethylene fed to the polymerization.

[0064] In one embodiment, the process is carried out in a reactor configuration comprising at least one tubular reactor. In further embodiments, the maximum temperature in each reaction zone is 200°C to 350°C, further 220°C to 325°C, and further 225°C to 300°C.

[0065] In one embodiment, the polymerization pressure at the first inlet of the reactor is 800 bar to 3600 bar, further 1500 bar to 3400 bar, and further 2000 bar to 3200 bar.

[0066] In one embodiment, the ratio of "the concentration of CTA in the feed to reaction zone i" to "the concentration of CTA in the feed added to reaction zone 1" is 1 or more.

[0067] In one embodiment, the ratio of "the concentration of CTA in the feed to reaction zone i" to "the concentration of CTA in the feed added to reaction zone 1" is less than 1, further less than 0.8, further less than 0.6, and further less than 0.4.

[0068] In one embodiment, the number of reaction zones ranges from 3 to 6.

[0069] Non-limiting examples of ethylene monomers used in the production of ethylene-based polymers include purified ethylene obtained by removing polar components from a loop recycle stream or by using a reaction system configuration such that only fresh ethylene is used to produce the ethylene-based polymers of the present invention. Further examples of ethylene monomers include ethylene monomers from a recycle loop.

[0070] In one embodiment, the ethylene-based polymer composition comprises an ethylene monomer BAIIM and one or more comonomers. Non-limiting examples of comonomers include α-olefins, acrylates, methacrylates, and anhydrides, each having 20 or fewer carbon atoms. The α-olefin comonomer can have 3 to 10 carbon atoms, or alternatively, the α-olefin comonomer can have 3 to 8 carbon atoms or 4 to 8 carbon atoms. Exemplary α-olefin comonomers include, but are not limited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 4-methyl-1-pentene.

[0071] Additive In one embodiment, a composition is provided. The composition includes BAIIM-PE and optionally one or more additives. Non-limiting examples of additives include stabilizers, plasticizers, antistatic agents, pigments, dyes, nucleating agents, fillers, slip agents, flame retardants, processing aids, smoke suppressants, viscosity control agents, and antiblocking agents. The present composition may include, for example, one or more additives less than 10% of the total weight, based on the weight of the composition. The composition having BAIIM-PE and one or more optional additives will hereinafter be interchangeably referred to as an “ethylene polymer composition”.

[0072] In one embodiment, the ethylene polymer composition is treated with one or more stabilizers, such as antioxidants like IRGANOX1010, IRGANOX1076, and IRGAFOS168.

[0073] Use The ethylene polymer composition of the present disclosure can be employed in various conventional thermoplastic fabrication processes for manufacturing useful articles including single-layer and multilayer films; molded articles such as blow-molded, injection-molded, or rotational-molded articles; coatings; fibers; and woven or non-woven fabrics.

[0074] The ethylene polymer composition of the present invention can be used in various films including, but not limited to, transparent shrink films, collation shrink films, cast stretch films, silage films, stretch hoods, sealants, and diaper backsheets. Other suitable uses include, but are not limited to, wires and cables, gaskets and profiles, adhesives, footwear components, and automotive interior parts.

[0075] The applicant has found that when BAIIM is added during the polymerization of ethylene, the melt strength of the LDPE resin for the same MI is improved when compared with the LDPE resin produced without adding BAIIM under the same polymerization conditions.

[0076] Rather than being limiting, several embodiments of the present disclosure will now be described in detail in the following examples by way of example only.

Example

[0077] The materials used in the examples are described in Table 1 below.

Table 2

[0078] Polymerization was carried out in a continuous stirred tank reactor. Four electric heater bands were used to heat and / or cool the reactor to 220 °C. The pressure in the reactor was about 800 bar. Propylene was used as a chain transfer agent (CTA). Ethylene and propylene were fed to the top of the reactor by a stirrer shaft. TPO and TPA diluted in Isopar E were injected into one side of the reactor to initiate the reaction. Also, diallyl maleate diluted in Isopar E was fed into a separate injector on the side of the reactor. The residence time in the reactor was about 1.5 minutes. All unreacted reactants and polymers were contained in a single outlet on the lower reactor. The polymer ( " BAIIM -PE") was separated from the remaining reactants by spraying, reducing the pressure of the stream to about 1 bar, and simultaneously cooling the stream to ambient temperature. Then, the polymer ( " BAIIM -PE") was collected in powder form.

[0079] The polymerization conditions for the comparative sample (CS) and the examples of the present invention (IE) IE1, IE2, and IE3 are provided in Table 2 below.

Table 3

[0080] The present disclosure is not limited to the embodiments and examples included herein, and is particularly intended to include modified forms of these embodiments, including portions of the embodiments and combinations of elements of different embodiments, as falling within the scope of the following claims. The present invention includes the following aspects. Item 1. An ethylene polymer comprising (i) ethylene, (ii) a BAIIM compound selected from the group consisting of bisallyl maleate, bisallyl fumarate, and mixtures thereof, and (iii) an optional comonomer selected from the group consisting of α-olefins, acrylates, and methacrylates, and optionally containing additives. Item 2. Having H NMR peaks at about 3.41 ppm and about 3.8 ppm, 1 the ethylene polymer according to Item 1. Item 3. The area of the H NMR peak at about 3.41 ppm 1 is at least four times larger than the area of the H NMR peak at about 3.8 ppm, 1 the ethylene polymer according to Item 2. Item 4. The H NMR peak at about 3.41 ppm 1 and the H NMR peak at about 3.8 ppm 1 with no 1 H NMR peak between them, the ethylene polymer according to any one of Items 1 to 3. A first IR peak centered at 1737 cm -1 and a second IR peak centered at 1785 cm -1 the ethylene polymer according to any one of Items 1 to 4. Item 6. The first IR peak at 1737 cm -1 includes a first carbonyl peak centered at 1735 cm -1 and a second carbonyl peak centered at 1740 cm -1 the ethylene polymer according to Item 5. Item 7. An ethylene polymer according to any one of items 1 to 6, having a melt index (I2) of 0.15 g / 10 min to 80.0 g / 10 min, measured according to ASTM D1238, condition 190 °C / 2.16 kg. Item 8. An ethylene polymer according to any one of items 1 to 7, containing units derived from 0.02% by weight to 5.0% by weight of a BAIIM compound, and having a melt strength of more than 15 cN to 20 cN. Item 9. A process comprising: reacting, under polymerization conditions, a component comprising (i) ethylene, (ii) a BAIIM compound selected from the group consisting of bisallyl maleate, bisallyl fumarate, and mixtures thereof, and (iii) an optional comonomer selected from the group consisting of α-olefins, acrylates, and methacrylates; forming an ethylene polymer; optionally adding additives. Item 10. A process according to item 9, comprising reacting a component comprising ethylene and a BAIIM compound in a tubular reactor; forming an ethylene polymer. Item 11. A process according to item 9 or 10, comprising reacting a component comprising ethylene and a BAIIM compound in an autoclave reactor; forming an ethylene polymer. Item 12. reacting a component comprising (i) ethylene and (ii) 30 ppm to 90 ppm of a BAIIM compound; forming an ethylene polymer having a melt strength of more than 15 cN to 20 cN. Item 13. The ethylene polymer according to any one of items 1 to 8, wherein the BAIIM compound is selected from the group consisting of (i) bisallyl maleate, (ii) bisallyl fumarate, and (iii) a mixture of bisallyl maleate and bisallyl fumarate. Item 14. The ethylene polymer according to item 13, wherein the BAIIM compound is bisallyl maleate having Structure I.

Chemical formula

Claims

**Claim 1** An ethylene polymer comprising a polymerization reaction product of (i) ethylene, (ii) 0.021% to 0.063% by weight of a BAIIM compound selected from the group consisting of bisallyl maleate, bisallyl fumarate, and mixtures thereof, and (iii) an optional comonomer selected from the group consisting of acrylates, methacrylates, and mixtures thereof, and optionally containing additives. **Claim 2** having １ １ H NMR peaks at 3.41 ppm and 3.8 ppm, the ethylene polymer according to claim 1. **Claim 3** At 3.41 ppm, １ the area of the 1H NMR peak is 3 to 7 times larger than the area of the 1H NMR peak at 3.8 ppm, １ The ethylene polymer according to claim 2. **Claim 4** At 3.41 ppm １ the 1H NMR peak and at 3.8 ppm １ there is no 1H NMR peak between the 1H NMR peaks, １ The ethylene polymer according to claim 2 or 3. **Claim 5** 1737 cm －１ a first IR peak centered at, and 1785 cm －１ The ethylene polymer according to any one of claims 1 to 4, having a second IR peak centered at. **Claim 6** 1737 cm －１ wherein the first IR peak at 1737 cm －１ comprises a first carbonyl peak centered at 1735 cm －１ and a second carbonyl peak centered at 1740 cm, the ethylene-based polymer according to claim 5. **Claim 7** An ethylene polymer according to any one of claims 1 to 6, having a melt index (I ２ ) measured according to ASTM D1238, condition 190 °C / 2.16 kg, of from 0.15 g / 10 min to 80.0 g / 10 min. **Claim 8** The ethylene polymer according to any one of claims 1 to 7, having a melt strength of more than 15 cN to 20 cN. **Claim 9** The ethylene polymer according to any one of claims 1 to 8, wherein the BAIIM compound is bisallyl maleate.

Images