Peroxide - treated blow - molded polymers with increased re - swell and constant die - swell

Abstract

Ethylene-based polymers are generally characterized by the following: a high load melt index of less than 12 g / 10 min, a weight average molecular weight of 200,000 to 550,000 g / mol, a number average molecular weight of 18,000 to 48,000 g / mol, a CY-a parameter of less than 0.12, a tanδ at 0.1 sec-1 of 0.5 to 0.9 degrees, a tanδ at 100 sec-1 of 0.5 to 0.75 degrees, and a viscosity at 0.001 sec-1 of 1.3×106 to 1×107 Pa-sec. These ethylene polymers can be produced by peroxide-treated bimodal molecular weight distribution bis-metallocene catalyzed resins and can be used to produce blow molded bottles and other blow molded products.

Description

Technical Field

[0001] The present disclosure generally relates to treating a peroxide-treated bimodal polyolefin base resin to produce an ethylene polymer, and subsequently using the ethylene polymer to form a blow molded product with a beneficial combination of both die swell and weight swell. Background Art

[0002] Polyolefins (such as high density polyethylene (HDPE) homopolymers and copolymers, and linear low density polyethylene (LLDPE) copolymers) can be produced using various combinations of catalyst systems and polymerization processes. Metallocene-based catalyst systems can, for example, produce ethylene polymers having good impact strength, tear resistance, and optical properties, but typically at the expense of poor extrusion processability and melt strength. Chromium-based catalyst systems can, for example, produce ethylene-based polymers having good extrusion processability and polymer melt strength typically due to their broad molecular weight distribution (MWD).

[0003] In some end-use applications (such as blow molding), it may be difficult to produce ethylene polymers having acceptable levels of die swell and weight swell, regardless of the catalyst system. Accordingly, the present invention generally relates to these objectives. Summary of the Invention

[0004] The Summary of the Invention is provided to introduce a series of concepts in a simplified form that will be further described in the Detailed Description below. The Summary of the Invention is not intended to identify essential or fundamental features of the claimed subject matter. The Summary of the Invention is also not intended to be used to limit the scope of the claimed subject matter.

[0005] The present invention generally relates to ethylene polymers (e.g., ethylene / α-olefin copolymers) characterized by a high load melt index (HLMI) of less than or equal to 12 g / 10 min, a weight average molecular weight (Mw) in the range of 200,000 to 550,000 g / mol, a number average molecular weight (Mn) in the range of 18,000 to 48,000 g / mol, a CY-α parameter of less than or equal to 0.12, a tanδ (tan d or tangent δ) at 0.1 sec in the range of 0.5 to 0.9 degrees, a tanδ at 100 sec in the range of 0.5 to 0.75 degrees, and a viscosity at 0.001 sec in the range of 1.3×10 -1 to 1×10 -1 Pa-sec (eta at 0.001 sec or eta at 0.001 sec 6 to 1×10 7 Pa-sec range at 0.001 sec -1 at 0.001 sec -1 or eta at 0.001 sec -1at η). These ethylene polymers can be used to produce various articles, such as blow molded bottles and other blow molded products.

[0006] Ethylene polymers can be produced, for example, by a method that includes contacting a base resin (e.g., an ethylene copolymer) with a peroxide compound to produce an ethylene polymer. In some aspects, the contacting step can include the step of melt processing a blend or mixture of the base resin and the peroxide compound at a suitable melt processing temperature, and generally, the amount of peroxide groups is in the range of 10 to 500 ppm, 25 to 400 ppm, or 50 to 350 ppm based on the weight of the base resin. Although not limited thereto, the base resin can generally be characterized by: an HLMI in the range of 2 to 40 g / 10 min, an Mw in the range of 250,000 to 550,000 g / mol, a CY-a parameter in the range of 0.12 to 0.3, a tanδ at 0.1 sec -1 at in the range of 0.8 to 1.05 degrees, a tanδ at 100 sec -1 at, and at 0.001 sec 5 from 1×10 6 to 3×10 -1 Pa-sec viscosity at.

[0007] The foregoing summary and the following detailed description both provide examples and are merely illustrative. Accordingly, the foregoing summary and the following detailed description should not be considered restrictive. In addition, features or variations can be provided in addition to those set forth herein. For example, certain aspects and embodiments may relate to various combinations and sub-combinations of features described in the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Graphs of the molecular weight distributions of the ethylene polymers of Examples 1-6 are presented.

[0009] Figure 2 Graphs of the molecular weight distributions of the ethylene polymers of Examples 7-12 are presented.

[0010] Figure 3 Graphs of the molecular weight distributions of the ethylene polymers of Examples 13-17 are presented.

[0011] Figure 4 Differential dynamic rheology graphs at 190 °C are presented, which show the rheological differences between Examples 2-6 and the baseline of Example 1 at different shear rates.

[0012] Figure 5Presents the differential dynamic rheology graph at 190 °C, which shows the rheological differences between Examples 8-12 and the baseline of Example 7 at different shear rates.

[0013] Figure 6 Presents the differential dynamic rheology graph at 190 °C, which shows the rheological differences between Examples 14-17 and the baseline of Example 13 at different shear rates.

[0014] Figure 7 Presents the graphs of die swell and reversion swell based on the peroxide load of Examples 1-6.

[0015] Figure 8 Presents the graphs of die swell and reversion swell based on the peroxide load of Examples 7-12.

[0016] Definition

[0017] To more clearly define the terms used herein, the following definitions are provided. Unless otherwise indicated, the following definitions apply to this disclosure. If a term is used in this disclosure but not specifically defined herein, the definition from the Compendium of Chemical Terminology, 2nd Edition (1997) from IUPAC may be applied, provided that the definition does not conflict with any other disclosure or the definitions applied herein or render any claim using the definition unclear or unworkable. If any definition or usage provided in any document incorporated herein by reference conflicts with the definition or usage provided herein, then the definition or usage provided herein shall prevail.

[0018] Herein, the features of the subject matter are described such that within a particular aspect, combinations of different features are conceivable. For each and every aspect and / or feature disclosed herein, all combinations are considered that do not detrimentally affect the designs, compositions, and / or methods described herein, with or without an explicit description of a particular combination. Additionally, unless otherwise explicitly stated, any aspect and / or feature disclosed herein can be combined to describe inventive features consistent with this disclosure.

[0019] Although the compositions and methods are described herein in terms of "comprising" various components or steps, the compositions and methods can also "consist essentially of" or "consist of" the various components or steps, unless otherwise specified.

[0020] Unless otherwise indicated, the terms "a / an", "the", etc. are intended to include plural alternatives, e.g., at least one / at least a kind of. For example, unless otherwise indicated, the disclosure of "additive" or "comonomer" is intended to cover respectively one additive or comonomer, or a mixture or combination of more than one additive or comonomer.

[0021] Generally, groups of elements are indicated using the numbering scheme indicated in the version of the Periodic Table published in Chemical and Engineering News, 63(5), 27, 1985. In some cases, groups of elements may be indicated using the common names assigned to the groups; for example, alkali metals indicate Group 1 elements, alkaline earth metals indicate Group 2 elements, transition metals indicate Groups 3-12 elements, and halogens or halide ions indicate Group 17 elements.

[0022] For any particular compound disclosed herein, unless otherwise indicated, the general structure or name presented also is intended to cover all structural isomers, conformational isomers, and stereoisomers that may be generated by a particular set of substituents. Thus, unless otherwise clearly indicated, the compounds generally referred to include all structural isomers; for example, pentane generally referred to includes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane, and butyl generally referred to includes n-butyl, sec-butyl, isobutyl, and tert-butyl. Additionally, when the context permits or requires, the reference to a general structure or name covers all enantiomers, diastereomers, and other optical isomers (whether in enantiomeric form or racemic form), as well as mixtures of stereoisomers. For any particular formula or name provided, any general formula or name provided also covers all conformational isomers, regioisomers, and stereoisomers that may be generated by a particular set of substituents.

[0023] The term "polymer" is generally used herein to include olefin homopolymers, copolymers, terpolymers, etc., as well as their alloys and blends. The term "polymer" also includes impact, block, graft, random, and alternating copolymers. Copolymers are derived from an olefin monomer and one olefin comonomer, while terpolymers are derived from an olefin monomer and two olefin comonomers. Thus, "polymer" encompasses copolymers and terpolymers derived from any olefin monomer and comonomer disclosed herein. Similarly, the scope of the term "polymerization" includes homopolymerization, copolymerization, and terpolymerization. Thus, ethylene polymers include ethylene homopolymers, ethylene copolymers (e.g., ethylene / α-olefin copolymers), ethylene terpolymers, etc., as well as their blends or mixtures. Thus, ethylene polymers encompass polymers commonly referred to in the art as LLDPE (linear low density polyethylene) and HDPE (high density polyethylene). For example, an olefin copolymer (such as an ethylene copolymer) can be derived from ethylene and a comonomer such as 1-butene, 1-hexene, or 1-octene. If the monomer and comonomer are ethylene and 1-hexene, respectively, the resulting polymer can be classified as an ethylene / 1-hexene copolymer. Unless otherwise specified, the term "polymer" also includes all possible geometric configurations, and such configurations can include isotactic, syndiotactic, and atactic symmetries. In addition, the "polymers" (e.g., ethylene polymers, base resins) disclosed herein may also be referred to herein as "polymer compositions".

[0024] As used herein, the term "contact" means materials or components that can be blended, mixed, slurried, dissolved, reacted, processed, compounded, or otherwise contacted or combined by some other means or by any suitable method. Unless otherwise specified, the materials or components can be contacted together in any order, in any manner, and for any length of time.

[0025] Although any methods, devices, and materials similar or equivalent to those described herein may be used in the practice or testing of the present invention, typical methods, devices, and materials are described herein.

[0026] All publications and patents mentioned herein are incorporated herein by reference for the purpose of describing and disclosing, for example, the constructs and methods described in the publications, which may be used in conjunction with the presently described invention.

[0027] The present invention discloses several types of ranges. When any type of range is disclosed or claimed, it is intended to separately disclose or claim each possible number that such range can reasonably cover, including the endpoints of the range and any sub-ranges and combinations of sub-ranges subsumed therein. As a representative example, in various aspects of the present invention, the Mw / Mn ratio of the ethylene polymer can be within certain ranges. By disclosing that the Mw / Mn ratio can be in the range of 6.5 to 20, it is intended to recite that the Mw / Mn ratio can be any ratio within that range and can include, for example, any range or combination within the range of 6.5 to 20, such as 7 to 17, 7.5 to 15, or 8 to 13, and so on. Similarly, all other ranges disclosed herein should be interpreted in a manner similar to this example.

[0028] Generally, quantities, sizes, formulations, parameters, ranges, or other quantities or characteristics are “about” or “approximately” whether or not expressly stated as such. Whether or not modified by the term “about” or “approximately”, the claims include equivalents of the quantity or characteristic. Detailed Description

[0029] The present invention generally relates to high molecular weight ethylene-based polymers having excellent melt strength and broad molecular weight distribution. Such polymers can be converted on blow molding equipment to form various articles.

[0030] The polymer swell characteristics upon exiting an accumulator head during blow molding equipment operation are critical. Appropriate swell is needed to properly fill the mold and ensure that the part has the appropriate weight (e.g., appropriate wall thickness). The polymer swell characteristics encompass two different swell behaviors: die swell and re-entry swell. It is known in the industry that changing the polymer structure to increase swell increases both die swell (e.g., how far the polymer parison expands in diameter upon exiting the accumulator head) and re-entry swell (e.g., how much polymer flows into the parison itself and increases the parison wall thickness compared to the die gap opening). Whether the polymer is a single peak chromium-based resin or a bimodal bis-metallocene-based resin, changes in the polymer structure (such as molecular weight distribution) increase or decrease both die swell and re-entry swell simultaneously.

[0031] Surprisingly and advantageously, the disclosed ethylene polymers (which have been treated with 10 - 300 ppm of active peroxide groups) exhibit divergence or decoupling of the die swell and re-entry swell characteristics. In particular, when the die swell remains constant, the re-entry swell surprisingly increases with increasing peroxide amount. Thus, the re-entry swell can be surprisingly increased or decreased without affecting the die swell, thereby allowing the blow molding equipment operator to independently control the part weight (e.g., the wall thickness of the part).

[0032] Ethylene Polymer

[0033] Generally, the polymers disclosed herein are ethylene-based polymers or ethylene polymers, including homopolymers of ethylene and copolymers, terpolymers, etc. of ethylene and at least one olefin comonomer. The comonomers copolymerizable with ethylene usually can have 3 to 20 carbon atoms in their molecular chains. For example, typical comonomers can include, but are not limited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, etc., or combinations thereof. In one aspect, the olefin comonomer can include C 3 -C 18 olefins; alternatively, the olefin comonomer can include C 3 -C 10 olefins; alternatively, the olefin comonomer can include C 4 -C 10 olefins; alternatively, the olefin comonomer can include C 3 -C 10 α-olefins; alternatively, the olefin comonomer can include C 4 -C 10 α-olefins; alternatively, the olefin comonomer can include 1-butene, 1-hexene, 1-octene, or any combination thereof; or alternatively, the comonomer can include 1-hexene.

[0034] In one aspect, the ethylene polymers of the present invention can include ethylene / α-olefin copolymers, and in another aspect, the ethylene polymers can include ethylene homopolymers, and in still another aspect, the ethylene polymers of the present invention can include ethylene / α-olefin copolymers and ethylene homopolymers. For example, the ethylene polymers can include ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, ethylene homopolymers, or any combination thereof; alternatively, ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, or any combination thereof; or alternatively, ethylene / 1-hexene copolymers.

[0035] Illustrative and non-limiting examples of the ethylene polymers (e.g., ethylene / α-olefin copolymers) described herein have a high load melt index (HLMI) of less than or equal to 12 g / 10 min, a weight average molecular weight (Mw) in the range of 200,000 to 550,000 g / mol, a number average molecular weight (Mn) in the range of 18,000 to 48,000 g / mol, a CY-a parameter of less than or equal to 0.12, a tanδ (tan d or tangent δ) at 0.1 sec -1 in the range of 0.5 to 0.9 degrees, a tanδ (tan d or tangent δ) at 100 sec -1 in the range of 0.5 to 0.75 degrees, and at 1.3×10 6 to 1×107 The viscosity within the range of 0.001 Pa-sec at 0.001 sec -1 (eta at 0.001 sec or η at 0.001 sec). Unless otherwise indicated, this illustrative and non-limiting example of the ethylene polymer may also have any polymer properties listed below and in any combination. -1 The eta at 0.001 sec or η at 0.001 sec -1 The ethylene polymer has a very low melt index, as indicated by a high load melt index (HLMI) of less than or equal to 12 g / 10 min. In some aspects, the HLMI of the ethylene polymer may be less than or equal to 10 or less than or equal to 8 g / 10 min. Typical ranges of HLMI include 1 to 12 g / 10 min, 1 to 10 g / 10 min, 1 to 8 g / 10 min, 2 to 12 g / 10 min, or 2 to 10 g / 10 min, etc.

[0036] In one aspect, the ethylene polymer may have an Mw within the range of 200,000 to 500,000 g / mol, 250,000 to 550,000 g / mol, 250,000 to 500,000 g / mol, 250,000 to 475,000 g / mol, 275,000 to 550,000 g / mol, or 275,000 to 475,000 g / mol. Additionally or alternatively, the ethylene polymer may have an Mw / Mn ratio that falls within the range of 6.5 to 20 (such as 7 to 17, 7.5 to 15, or 8 to 13). Additionally or alternatively, the ethylene polymer may have an Mz / Mw ratio that falls within the range of 4 to 9 (such as 4 to 8, 4.5 to 7.5, or 5 to 7).

[0037]

[0038] ​In one aspect, the ethylene polymer may have an Mp in the range of 60,000 to 110,000 g / mol, 65,000 to 105,000 g / mol, or 70,000 to 100,000 g / mol. Additionally or alternatively, the ethylene polymer may have an Mn in the range of 20,000 to 46,000 g / mol, 22,000 to 46,000 g / mol, 20,000 to 42,000 g / mol, or 22,000 to 40,000 g / mol. Additionally or alternatively, ethylene polymers consistent with certain aspects of the present invention generally may have a bimodal molecular weight distribution (as determined using gel permeation chromatography (GPC) or other related analytical techniques). Generally, in a bimodal molecular weight distribution, there is a valley between the peaks, and the peaks may be resolved or deconvoluted. Typically, a bimodal molecular weight distribution may be characterized as having an identifiable high molecular weight component (or distribution) and an identifiable low molecular weight component (or distribution). Illustrative unimodal MWD curves and bimodal MWD curves are shown in U.S. Patent No. 8,383,754, which is incorporated herein by reference in its entirety.

[0039] The density of the ethylene-based polymers disclosed herein is generally greater than or equal to 0.935 g / cm 3 and less than or equal to 0.965 g / cm 3 . However, in certain aspects, the density may be in the range of 0.94 to 0.965 g / cm 3 , 0.945 to 0.965 g / cm 3 , 0.94 to 0.96 g / cm 3 , 0.945 to 0.96 g / cm 3 , 0.95 to 0.965 g / cm 3 or 0.95 to 0.96 g / cm 3 .

[0040] The ethylene polymers described herein have high viscosity at low shear rates, which translates into excellent polymer melt strength. The viscosity at 190 °C at 0.001 sec -1 (eta at 0.001 sec -1 or η at 0.001 sec -1 ) generally falls in the range of 1.3×10 6 to 1×10 7 Pa-sec, such as 1.3×10 6 to 6×10 6 Pa-sec; alternatively, 1.3×10 6 to 5×10 6 Pa-sec; alternatively, 1.5×10 6to 1×10 7 Pa-sec; alternatively, 1.5×10 6 to 6×10 6 Pa-sec; alternatively, 1.5×10 6 to 5×10 6 Pa-sec; alternatively, 2×10 6 to 6×10 6 Pa-sec; or alternatively, 2×10 6 to 5×10 6 Pa-sec. In some aspects, the ethylene polymer may have a zero-shear viscosity (η 8 at 190 °C in the range of 1×10 30 to 1×10 8 Pa-sec, 1×10 28 to 1×10 10 Pa-sec, 1×10 30 to 1×10 10 Pa-sec, 1×10 27 to 1×10 12 Pa-sec, or 1×10 27 to 1×10 0 Pa-sec, etc. Additionally or alternatively, the ethylene polymer may have a relaxation time (τ 3 in the range of 5×10 25 to 1×10 3 s (such as 6×10 23 to 1×10 5 sec, 1×10 25 to 1×10 5 sec, 1×10 23 to 1×10 7 sec, or 1×10 23 to 1×10 η s, etc.). The zero-shear viscosity and the relaxation time are determined from viscosity data measured at 190 °C and using the Carreau - Yasuda (CY) empirical model (with creep adjustment) as described herein.

[0041] The ethylene polymer may have a CY-a parameter less than or equal to 0.12 (such as less than or equal to 0.11, less than or equal to 0.1, less than or equal to 0.08, or less than or equal to 0.06). Typically, the range includes 0.01 to 0.12, 0.01 to 0.1, 0.01 to 0.08, or 0.01 to 0.06, etc. Additionally or alternatively, the ethylene polymer may have, in one aspect, a tanδ in the range of 0.5 to 0.9 degrees, in another aspect 0.5 to 0.85 degrees, in another aspect 0.5 to 0.8 degrees, in another aspect 0.55 to 0.9 degrees, in another aspect 0.55 to 0.85 degrees, in another aspect 0.6 to 0.9 degrees, in yet another aspect 0.6 to 0.85 degrees, and in still another aspect 0.6 to 0.8 degrees at 0.1 sec -1 under. Additionally or alternatively, the ethylene polymer may have, in one aspect, a tanδ in the range of 0.5 to 0.75 degrees, in another aspect 0.5 to 0.72 degrees, in another aspect 0.5 to 0.7 degrees, in another aspect 0.52 to 0.75 degrees, in another aspect 0.52 to 0.72 degrees, in another aspect 0.52 to 0.7 degrees, in still another aspect 0.55 to 0.75 degrees, and in yet another aspect 0.55 to 0.72 degrees at 100 sec -1 under. Additionally or alternatively, the ethylene polymer may have a viscosity (eta at 100 or η at 100) at 190 °C at 100 sec in the range of 1700 to 3300 Pa-sec, 1800 to 3200 Pa-sec, 1900 to 3100 Pa-sec, or 2000 to 3000 Pa-sec 1 under. These rheological parameters are determined from viscosity data measured at 190 °C and using the Carreau - Yasuda (CY) empirical model (with creep adjustment) described herein.

[0042] Furthermore, the ethylene polymer may have an inverse comonomer distribution. Generally, the comonomer incorporation in the higher molecular weight fraction of the polymer is higher than that in the lower molecular weight fraction. Typically, as the molecular weight increases, the comonomer incorporation increases. In one aspect, the number of short chain branches (SCB) per 1000 total carbon atoms of the polymer may be greater at Mw than at Mn. In another aspect, the number of SCB per 1000 total carbon atoms of the polymer may be greater at Mz than at Mw. In still another aspect, the number of SCB per 1000 total carbon atoms of the polymer may be greater at Mz than at Mn.

[0043] In one aspect, the ethylene polymers described herein can be reactor products (e.g., single reactor products), e.g., not a post-reactor blend of, for example, two polymers having different molecular weight characteristics. Those skilled in the art will readily recognize that a physical blend of two different polymer resins can be prepared, but this requires additional processing and complexity not needed for reactor products.

[0044] In addition, the ethylene polymers can be produced from base resins that can be prepared using metallocene catalyst systems. Ziegler-Natta and chromium-based catalyst systems are not required. Thus, the ethylene polymers can be free of measurable amounts of chromium or titanium or vanadium or magnesium (catalyst residues), i.e., less than 0.1 ppm by weight. In some aspects, the ethylene polymers can independently contain less than 0.08 ppm, less than 0.05 ppm, or less than 0.03 ppm of chromium (or titanium, or vanadium, or magnesium).

[0045] The ethylene polymers can be in any suitable form, such as fluff, powder, granules, pellets, etc. Generally, the ethylene polymers are in the form of pellets. The ethylene polymers can contain one or more additives, non-limiting examples of which can include antioxidants, acid scavengers, anti-caking additives, slip additives, colorants, fillers, processing aids, UV inhibitors, etc. and combinations thereof.

[0046] Aspects of the invention also relate to the performance of these ethylene polymers (e.g., ethylene / 1-hexene copolymers) on representative blow molding equipment, as described below. Advantageously, the ethylene polymers can have die swell (quantified by part weight in grams) decoupled from draw down (quantified by flat bottom in inches), and the difference between the two can depend on the amount of peroxide used to produce the ethylene polymers. In one aspect, for example, the ethylene polymers can have a die swell to draw down (die swell quantified by part weight in grams and draw down quantified by flat bottom in inches) ratio in the range of 200 to 280, in another aspect 210 to 270, in yet another aspect 230 to 280, and in still another aspect 230 to 270. Also advantageously, the ethylene polymers have exceptional melt strength during blow molding, which can be quantified by a hang time of at least 40 sec, and more typically at least 50 s or at least 100 sec.

[0047] Consistent with aspects of the present invention, ethylene polymers can be produced from a base resin (discussed below herein) via a method that includes contacting the base resin with a peroxide compound to produce an ethylene polymer (any ethylene polymer disclosed herein). Generally, the amount (ppm by weight) of the peroxide compound used in the method is of less interest because the amount of peroxide groups is more important and the molecular weight and the number of peroxide groups per peroxide compound vary among all suitable peroxide compounds. Generally, based on the weight of the base resin, the amount of peroxide groups can be in the range of 10 to 500 ppm, 25 to 400 ppm, 50 to 400 ppm, 50 to 350 ppm, 75 to 400 ppm, or 100 to 300 ppm peroxide groups based on the weight of the base resin.

[0048] Accordingly, the base resin and the peroxide compound can be contacted at a temperature sufficient to produce peroxide groups in an amount of 10 to 500 ppm, 25 to 400 ppm, 50 to 400 ppm, 50 to 350 ppm, 75 to 400 ppm, or 100 to 300 ppm peroxide groups based on the weight of the base resin.

[0049] In one aspect, the step of contacting the base resin with the peroxide compound can include melt processing a blend (or mixture) of the base resin and the peroxide compound at any suitable melt processing temperature, such as a temperature in the range of 120 to 300 °C, a temperature in the range of 150 to 250 °C, a temperature in the range of 175 to 225 °C, and the like. The appropriate temperature can depend on the composition of the peroxide compound and its temperature at which it releases peroxide groups. Prior to contacting the peroxide compound, the base resin can be in any suitable form, including, for example, fluff, powder, pellet, granule, solution, slurry, emulsion, etc. Similarly, the peroxide compound can be in solid form, in liquid form, in solution, or in slurry. One particular method uses a masterbatch of the peroxide compound and contacts the base resin (in fluff form) during melt processing. The masterbatch of the peroxide compound can contain any suitable organic or inorganic carrier, but typically contains a high melt flow carrier resin, such as polyethylene or polypropylene.

[0050] The present invention is not limited to any particular method of contacting the base resin and the peroxide compound and melt-processing the base resin and the peroxide compound. As will be appreciated by those skilled in the art, various mixing and / or compounding methods can be employed. In one aspect, the melt-processing of the base resin and the peroxide compound can be carried out in a single-screw extrusion system. In another aspect, the melt-processing of the base resin and the peroxide compound can be carried out in a twin-screw extrusion system (e.g., a counter-rotating mixer or a co-rotating twin-screw extrusion system). The twin-screw extrusion system can include any combination of feed elements, melting elements, mixing elements, and conveying elements. For example, the twin-screw extrusion system can contain all or most of the mixing elements.

[0051] The peroxide compound can be any compound containing one or more peroxide (O-O) groups, and suitable examples thereof can include, but are not limited to, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, tert-butyl cumyl peroxide, n-butyl-4,4'-di(tert-butylperoxy)valerate, etc. The peroxide compound can be added, for example, as solid small particles, dissolved in mineral oil, or in liquid form.

[0052] One or more additives can also be added during the conversion of the base resin (and the peroxide compound) into an ethylene polymer. Non-limiting examples of suitable additives can include antioxidants, acid scavengers, anti-caking additives, slip additives, colorants, fillers, processing aids, ultraviolet inhibitors, etc. If desired, a combination of two or more additives can be contacted with the base resin and the peroxide compound.

[0053] Articles and products

[0054] Articles can be formed from and / or can comprise the ethylene polymers (e.g., ethylene copolymers) of the present invention and are thus encompassed herein. For example, articles that can comprise the polymers of the present invention can include, but are not limited to, agricultural films, automotive parts, bottles, chemical containers, drums, fibers or fabrics, food packaging films or containers, food service articles, fuel tanks, geomembranes, household containers, liners, molded products, medical devices or materials, outdoor storage products (e.g., panels for outdoor shed walls), outdoor play equipment (e.g., kayaks, bases for basketball goals), tubing, sheets or tapes, toys, or traffic barriers, etc. A variety of processes can be employed to form these articles. Non-limiting examples of such processes include injection molding, blow molding, rotational molding, film extrusion, sheet extrusion, profile extrusion, thermoforming, etc. Additionally, additives and modifiers are typically added to these polymers to provide beneficial polymer processing or end-use product properties. Such processes and materials are described in Modern Plastics Encyclopedia, November 1995 issue, Volume 72, Number 12; and Film Extrusion Manual - Process, Materials, Properties, TAPPI Press, 1992; the disclosures of which are incorporated herein by reference in their entirety. In some aspects of the present invention, an article can comprise any of the ethylene polymers described herein, and the article can be or can comprise a blow molded product, such as a blow molded bottle.

[0055] Base resin

[0056] Generally, the base resin used to produce the ethylene polymers can be any homopolymer of ethylene, or a copolymer, terpolymer, etc. of ethylene and at least one of the olefin comonomers disclosed above with respect to the ethylene polymers. Thus, the base resin can comprise an ethylene / α-olefin copolymer, and in another aspect, the base resin can comprise an ethylene homopolymer, and in yet another aspect, the base resin can comprise an ethylene / α-olefin copolymer and an ethylene homopolymer. Thus, the base resin can comprise an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, an ethylene / 1-octene copolymer, an ethylene homopolymer, or any combination thereof; alternatively, an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, an ethylene / 1-octene copolymer, or any combination thereof; or alternatively, an ethylene / 1-hexene copolymer. Typically, for example, if the base resin is an ethylene / 1-hexene copolymer, the ethylene polymer produced from the base resin is also an ethylene / 1-hexene copolymer, although mixtures and combinations of various types of homopolymers and copolymers can be used.

[0057] To produce ethylene polymers having the properties and benefits disclosed herein, a suitable base resin is used. Illustrative and non-limiting examples of the base resins of the present invention (e.g., ethylene copolymers) may have an HLMI in the range of 2 to 40 g / 10 min, an Mw in the range of 250,000 to 550,000 g / mol, a CY-a parameter in the range of 0.12 to 0.3, a tanδ at 0.1 sec in the range of 0.8 to 1.05 degrees, a tanδ at 100 sec in the range of 0.4 to 0.6 degrees, and a viscosity at 0.001 sec in the range of 1×10 to 3×10 Pa-sec. Unless otherwise indicated, this illustrative and non-limiting example of a base resin consistent with the present invention may also have any polymer properties listed below and in any combination. -1 At -1 100 sec 5 a tanδ in the range of 0.4 to 0.6 degrees. 6 And a viscosity at 0.001 sec in the range of 1×10 -1 to 3×10 Pa-sec.

[0058] In some aspects, the base resin for producing an ethylene polymer may have an HLMI in the range of, for example, 2 to 20 g / 10 min, 2 to 12 g / 10 min, 4 to 40 g / 10 min, 4 to 20 g / 10 min, 4 to 15 g / 10 min, or 4 to 12 g / 10 min.

[0059] In one aspect, the base resin may have an Mw in the range of 250,000 to 500,000 g / mol, 250,000 to 475,000 g / mol, 300,000 to 550,000 g / mol, or 300,000 to 500,000 g / mol. Additionally or alternatively, the base resin may have an Mw / Mn ratio falling within the range of 9 to 20 (such as 11 to 19, 12 to 18, or 13 to 16). Additionally or alternatively, the base resin may have an Mz / Mw ratio falling within the range of 4 to 9 (such as 5 to 8, 5 to 7.5, or 6 to 8).

[0060] In one aspect, the base resin may have an Mp in the range of 60,000 to 110,000 g / mol, 65,000 to 105,000 g / mol, or 65,000 to 100,000 g / mol. Additionally or alternatively, the base resin may have an Mn in the range of 18,000 to 48,000 g / mol, 20,000 to 42,000 g / mol, or 22,000 to 38,000 g / mol. Additionally or alternatively, the base resin used to produce the ethylene polymers disclosed herein typically may have a bimodal molecular weight distribution (as determined using gel permeation chromatography (GPC) or other related analytical techniques). Generally speaking, in a bimodal molecular weight distribution, there is a valley between the peaks, and the peaks may be separated or deconvoluted. Typically, a bimodal molecular weight distribution may be characterized as having an identifiable high molecular weight component (or distribution) and an identifiable low molecular weight component (or distribution). Illustrative unimodal MWD curves and bimodal MWD curves are shown in U.S. Patent No. 8,383,754, which is incorporated herein by reference in its entirety.

[0061] The density of the base resin used to produce the ethylene polymers disclosed herein is generally greater than or equal to 0.935 g / cm 3 and less than or equal to 0.965 g / cm 3 . However, in certain aspects, the density may be in the range of 0.94 to 0.965 g / cm 3 , 0.945 to 0.965 g / cm 3 , 0.94 to 0.96 g / cm 3 , 0.945 to 0.96 g / cm 3 , 0.95 to 0.965 g / cm 3 or 0.95 to 0.96 g / cm 3 .

[0062] For the base resin, the viscosity at 190 °C at 0.001 sec -1 (eta at 0.001 sec -1 or η at 0.001 sec -1 ) generally falls within the range of 1×10 5 to 2×10 6 Pa-sec; alternatively, 1×10 5 to 1.8×10 6 Pa-sec; alternatively, 8×10 5 to 3×10 6 Pa-sec; alternatively, 8×10 5 to 2×10 6 Pa-sec; or alternatively, 8×10 5from 1.8×10 6 Pa-sec. In some aspects, the base resin may have a zero-shear viscosity (η 6 from 1×10 9 to 1×10 6 Pa-sec, 1×10 8 to 2×10 6 Pa-sec, 4×10 9 to 1×10 6 Pa-sec, or 4×10 8 to 2×10 0 ) at 190 °C. Like ethylene polymers, the viscosity data of the base resin is measured at 190 °C and using the Carreau-Yasuda (CY) empirical model (with creep adjustment) described herein.

[0063] Typical ranges of the CY-a parameter of the base resin include 0.12 to 0.25, 0.13 to 0.3, 0.13 to 0.25, or 0.14 to 0.25, etc. Additionally or alternatively, the base resin may have a tanδ at 0.1 sec -1 in the range of 0.5 to 0.85 degrees in one aspect, 0.8 to 1 degree in another aspect, 0.83 to 1.05 degrees in another aspect, 0.83 to 1 degree in yet another aspect, 0.85 to 1.05 degrees in still another aspect, and 0.85 to 1 degree in yet another aspect. Additionally or alternatively, the base resin may have a tanδ at 100 sec -1 in the range of 0.4 to 0.58 degrees in one aspect, 0.4 to 0.55 degrees in another aspect, 0.45 to 0.6 degrees in another aspect, 0.45 to 0.58 degrees in yet another aspect, and 0.45 to 0.55 degrees in still another aspect. As described above, these rheological parameters are determined from the viscosity data measured at 190 °C and using the Carreau-Yasuda (CY) empirical model (with creep adjustment) described herein.

[0064] The base resin described herein may have an inverse comonomer distribution. Generally, the comonomer incorporation of the higher molecular weight fraction of the polymer is higher than that of the lower molecular weight fraction. Typically, as the molecular weight increases, the comonomer incorporation increases. In one aspect, the number of short chain branches (SCB) per 1000 total carbon atoms of the polymer may be greater at Mw than at Mn. In another aspect, the number of SCB per 1000 total carbon atoms of the polymer may be greater at Mz than at Mw. In yet another aspect, the number of SCB per 1000 total carbon atoms of the polymer may be greater at Mz than at Mn.

[0065] In one aspect, the base resin can be a reactor product (e.g., a single reactor product), e.g., not a post-reactor blend of two polymers having different molecular weight characteristics, for example. Those skilled in the art will readily recognize that physical blends of two different polymer resins can be prepared, but this requires additional processing and complexity not needed for reactor products.

[0066] The base resin can be produced using a bis-metallocene catalyst system and thus does not require Ziegler-Natta and chromium-based catalyst systems. Thus, the base resin can be free of measurable amounts of chromium or titanium or vanadium or magnesium (catalyst residues), i.e., less than 0.1 ppm by weight. In some aspects, the base resin can independently contain less than 0.08 ppm, less than 0.05 ppm, or less than 0.03 ppm of chromium (or titanium, or vanadium, or magnesium).

[0067] Although one or more additives can be incorporated during the conversion of the base resin to an ethylene polymer or during the conversion of the ethylene polymer to a blow molded product (or to other articles), the base resin can also contain one or more suitable additives. Non-limiting examples of suitable additives can include antioxidants, acid scavengers, anti-caking additives, slip additives, colorants, fillers, processing aids, UV inhibitors, etc. Combinations of two or more additives can be present in the base resin.

[0068] As described herein, the performance of the base resin on a representative blow molding apparatus can be characterized in one aspect by a ratio of die swell to draw down (die swell: draw down) in the range of 150 to 225, 180 to 225, or 170 to 200. In another aspect, the base resin can be characterized by having a hang-up time in the range of 10 to 45 sec, 15 to 45 sec, or 20 to 45 sec.

[0069] Consistent with aspects of the present invention, the base resin can be produced using a bis-metallocene catalyst system. Although not limited thereto, catalyst component I can comprise a suitable non-bridged metallocene compound, catalyst component II can comprise a suitable bridged metallocene compound, and the catalyst system can further comprise a suitable activator and optionally a suitable cocatalyst.

[0070] Referring first to catalyst component I, it can comprise a non-bridged zirconium or hafnium-based metallocene compound containing two cyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl and an indenyl group. In one aspect, catalyst component I can comprise a non-bridged zirconium or hafnium-based metallocene compound containing two cyclopentadienyl groups. In another aspect, catalyst component I can comprise a non-bridged zirconium or hafnium-based metallocene compound containing two indenyl groups. In yet another aspect, catalyst component I can comprise a non-bridged zirconium or hafnium-based metallocene compound containing a cyclopentadienyl group and an indenyl group.

[0071] Now referring to catalyst component II, which can be a bridged metallocene compound. In one aspect, for example, catalyst component II can comprise a bridged zirconium or hafnium-based metallocene compound. In another aspect, catalyst component II can comprise a bridged zirconium or hafnium-based metallocene compound having an alkenyl substituent. In yet another aspect, catalyst component II can comprise a bridged zirconium or hafnium-based metallocene compound having an alkenyl substituent and a fluorenyl group. In still another aspect, catalyst component II can comprise a bridged zirconium or hafnium-based metallocene compound having a cyclopentadienyl group and a fluorenyl group and having an alkenyl substituent on the bridging group and / or on the cyclopentadienyl group. Additionally, catalyst component II can comprise a bridged metallocene compound having an aryl group on the bridging group.

[0072] In addition, the dual catalyst system contains an activator. For example, the catalyst system can contain an activator-carrier, an aluminoxane compound, an organoboron or organoborate compound, an ionizing ionic compound, etc., or any combination thereof. The catalyst system can contain one or more than one activator. When present, the cocatalyst can include, but is not limited to, alkylboron, alkylaluminum, and alkylzinc compounds such as tri-n-butylborane, tripropylborane, triethylborane, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride, ethoxydiethylaluminum, diethylaluminum chloride, dimethylzinc, diethylzinc, dipropylzinc, dibutylzinc, dineopentylzinc, etc., or combinations thereof. Representative catalyst systems useful for producing the base resin are disclosed in U.S. Patent Nos. 9,169,337, 9,273,170, 9,493,589, and 9,650,459, which are hereby incorporated by reference in their entirety.

[0073] Using any suitable olefin polymerization process, using various types of polymerization reactors, polymerization reactor systems, and polymerization reaction conditions, the base resin can be produced from these catalyst systems. One such olefin polymerization process for polymerizing olefins in the presence of the catalyst composition of the present invention can include contacting the catalyst composition with ethylene and optionally an olefin comonomer(s) in a polymerization reactor system under polymerization conditions to produce the base resin.

[0074] As used herein, "polymerization reactor" includes any polymerization reactor capable of polymerizing olefin monomers and comonomers (one or more comonomers) to produce homopolymers, copolymers, terpolymers, etc. Various types of polymerization reactors include those that may be referred to as batch reactors, slurry reactors, gas-phase reactors, solution reactors, high-pressure reactors, tubular reactors, autoclave reactors, etc., or combinations thereof; or alternatively, a polymerization reactor system may comprise a slurry reactor, a gas-phase reactor, a solution reactor, or a combination thereof. The polymerization conditions for the various reactor types are well known to those skilled in the art. A gas-phase reactor may comprise a fluidized bed reactor or a staged horizontal reactor. A slurry reactor may comprise a vertical or horizontal loop. A high-pressure reactor may comprise an autoclave reactor or a tubular reactor. The reactor type may include a batch process or a continuous process. A continuous process may use batch or continuous product discharge. The polymerization reactor system and process may also include partial or full direct recycle of unreacted monomers, unreacted comonomers, and / or diluents.

[0075] A polymerization reactor system may also comprise a single reactor or multiple reactors (two reactors, more than two reactors, etc.) of the same or different types. For example, the polymerization reactor system may comprise a slurry reactor, a gas-phase reactor, a solution reactor, or a combination of two or more of these reactors. Producing a polymer in multiple reactors may include several stages in at least two separate polymerization reactors interconnected by transfer means such that the polymer produced in the first polymerization reactor can be transferred into the second reactor. The polymerization conditions required for one of the reactors may be different from the operating conditions of the other reactors. Alternatively, polymerization in multiple reactors may include manually transferring the polymer from one reactor to a subsequent reactor to continue polymerization. A multi-reactor system may include any combination, including but not limited to multiple loop reactors, multiple gas-phase reactors, a combination of a loop reactor and a gas-phase reactor, multiple high-pressure reactors, or a combination of a high-pressure reactor with a loop reactor and / or a gas-phase reactor. The multiple reactors may be operated in series, in parallel, or in series and parallel. Thus, the present invention encompasses polymerization reactor systems including a single reactor, including two reactors, and including more than two reactors. In certain aspects of the present invention, the polymerization reactor system may include a slurry reactor, a gas-phase reactor, a solution reactor, and multi-reactor combinations thereof.

[0076] According to one aspect, a polymerization reactor system can include at least one loop slurry reactor that includes vertical or horizontal circulation. Monomers, diluents, catalysts, and comonomers can be continuously fed into the loop reactor where polymerization occurs. Generally, a continuous process can include continuously introducing monomers / comonomers, catalysts, and diluents into a polymerization reactor and continuously removing a suspension containing polymer particles and diluent from the reactor. The reactor effluent can be flash vaporized to remove solid polymer from the liquid containing diluent, monomer, and / or comonomer. A variety of techniques can be used for this separation step, including but not limited to flash vaporization, which can include any combination of heating and pressure reduction, separation by cyclone action in a cyclone separator or hydrocyclone, or separation by centrifugation.

[0077] Typical slurry polymerization processes (also known as particulate form processes) are disclosed, for example, in U.S. Patent Nos. 3,248,179, 4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, 6,833,415, and 8,822,608, each of which is incorporated herein by reference in its entirety.

[0078] Suitable diluents for use in slurry polymerization include but are not limited to the monomers being polymerized and hydrocarbons that are liquid under the reaction conditions. Examples of suitable diluents include but are not limited to hydrocarbons such as propane, cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, and n-hexane. Some loop polymerization reactions can occur under bulk conditions without the use of a diluent.

[0079] According to yet another aspect, a polymerization reactor system can include at least one gas phase reactor (e.g., a fluidized bed reactor). Such a reactor system can use a continuous recycle stream containing one or more monomers that continuously circulates through the fluidized bed in the presence of a catalyst under polymerization conditions. The recycle stream can leave the fluidized bed and be recycled back into the reactor. At the same time, the polymer product can be withdrawn from the reactor, and new or fresh monomers can be added to replace the polymerized monomers. Such a gas phase reactor can include a multi-step gas phase polymerization process for olefins where the olefins are polymerized in the gas phase in at least two separate gas phase polymerization zones while feeding the catalyst-containing polymer formed in the first polymerization zone to the second polymerization zone. Representative gas phase reactors are disclosed in U.S. Patent Nos. 5,352,749, 4,588,790, 5,436,304, 7,531,606, and 7,598,327, each of which is incorporated herein by reference in its entirety.

[0080] According to yet another aspect, the polymerization reactor system may include a high-pressure polymerization reactor, such as a tubular reactor or an autoclave reactor. The tubular reactor may have several zones where fresh monomer, initiator, or catalyst is added. The monomer may be entrained in an inert gas stream and introduced into one zone of the reactor. The initiator, catalyst, and / or catalyst components may be entrained in a gas stream and introduced into another zone of the reactor. The gas streams may be commingled for polymerization. Heat and pressure may be appropriately applied to obtain optimal polymerization reaction conditions.

[0081] According to yet another aspect, the polymerization reactor system may include a solution polymerization reactor, where the monomer / copolymer is contacted with the catalyst composition by suitable agitation or other means. A carrier comprising an inert organic diluent or an excess monomer may be used. If necessary, the monomer / copolymer may be contacted with the catalytic reaction product in the gas phase in the presence or absence of a liquid material. The polymerization zone may be maintained at a temperature and pressure such that a polymer solution is formed in the reaction medium. Agitation may be used to obtain better temperature control and to maintain a uniform polymerization mixture throughout the polymerization zone. Appropriate means are used to dissipate the exotherm of polymerization.

[0082] The polymerization reactor system may also include any combination of at least one feedstock feeding system, at least one feeding system for the catalyst or catalyst components, and / or at least one polymer recovery system. Suitable reactor systems may also include systems for feedstock purification, catalyst storage and preparation, extrusion, reactor cooling, polymer recovery, fractionation, recycling, storage, loading, laboratory analysis, and process control. Depending on the desired properties of the olefin polymer, hydrogen may be added to the polymerization reactor as needed (e.g., continuously, in pulses, etc.).

[0083] Polymerization conditions that can be controlled to increase efficiency and provide the desired polymer properties may include temperature, pressure, and the concentration of various reactants. The polymerization temperature may affect catalyst productivity, polymer molecular weight, and molecular weight distribution. For example, to produce a specific grade of olefin polymer (or ethylene polymer), various polymerization conditions may be kept substantially constant. According to the Gibbs Free energy equation, a suitable polymerization temperature may be any temperature below the depolymerization temperature. Typically, depending on the type of polymerization reactor, this includes, for example, 60°C to 280°C, or 60°C to 120°C. In some reactor systems, the polymerization temperature may generally be in the range of 70°C to 100°C, or 75°C to 95°C.

[0084] Suitable pressures will also vary depending on the reactor and type of polymerization. Pressures for liquid-phase polymerization in a loop reactor are typically less than 1000 psig (6.9 MPa). Pressures for gas-phase polymerization are generally 200 to 500 psig (1.4 MPa to 3.4 MPa). High-pressure polymerization in a tubular reactor or autoclave reactor generally operates at 20,000 to 75,000 psig (138 to 517 MPa). The polymerization reactor can also be operated in the supercritical region, which generally occurs at higher temperatures and pressures. Operation above the critical point (supercritical phase) of the pressure / temperature diagram can provide advantages for the polymerization reaction process.

[0085] Consistent with aspects of the present invention, the olefin monomer used in the polymerization process is ethylene, and the comonomer can comprise C 3 -C 10 α-olefins; alternatively, the comonomer can comprise 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, styrene, or any combination thereof; alternatively, the comonomer can comprise 1-butene, 1-hexene, 1-octene, or any combination thereof; alternatively, the comonomer can comprise 1-butene; alternatively, the comonomer can comprise 1-hexene; or alternatively, the comonomer can comprise 1-octene.

[0086] Examples

[0087] The present invention is further illustrated by the following examples, which should not be construed as limiting the scope of the present invention in any way. After reading the description herein, various other aspects, embodiments, modifications, and their equivalents can be envisioned by those of ordinary skill in the art without departing from the spirit of the present invention or the scope of the appended claims.

[0088] Determine the high load melt index (HLMI, I 21 , g / 10 min) at 190 °C with a 21.6 kg weight according to ASTM D1238. The density can be determined in grams per cubic centimeter (g / cm 3 3) on compression molded samples cooled at 15 °C per hour and conditioned at room temperature for 40 hours according to ASTM D1505 and ASTM D4703.

[0089] The molecular weight and molecular weight distribution were obtained using a PL-GPC 220 (Polymer Labs, Agilent Company) system equipped with an IR4 detector (Polymer Char, Spain) and three (3) Styragel HMW-6E GPC columns (Waters, MA) operating at 145 °C. The mobile phase, 1,2,4-trichlorobenzene (TCB), containing 0.5 g / L 2,6-di-tert-butyl-4-methylphenol (BHT), was set to a flow rate of 1 mL / min, and the polymer solution concentration was approximately 1 mg / mL, depending on the molecular weight. Prior to transferring the solution to a sample vial for injection, sample preparation was carried out at 150 °C with occasional and gentle stirring for a nominal 4 h. An injection volume of approximately 400 μL was used. Using a broad HDPE polyethylene resin MARLEX BHB5003 from Chevron Phillips Chemical Company as a standard, the molecular weight and molecular weight distribution were derived using an integral calibration method. The integral table for the standard was pre-determined in a separate experiment using SEC-MALS. Mn is the number-average molecular weight, Mw is the weight-average molecular weight, Mz is the z-average molecular weight, and Mp is the peak molecular weight (the molecular weight position at the highest point of the molecular weight distribution curve).

[0090] Melt rheology characterization was conducted as follows. Small-strain (10%) oscillatory shear measurements were performed on an Anton Paar MCR 501 rheometer using a parallel plate geometry. All rheology tests were carried out at 190 °C. The data of the complex viscosity |η*| versus frequency (ω) were then curve-fitted using a modified three-parameter Carreau-Yasuda (CY) empirical model to obtain the zero-shear viscosity - η 0 , the characteristic viscosity relaxation time - τ η and the width parameter - a (CY-a parameter). The simplified Carreau-Yasuda (CY) empirical model is as follows.

[0091]

[0092] where: |η*(ω)| = the magnitude of the complex shear viscosity,

[0093] η 0 = the zero-shear viscosity;

[0094] τ η = the viscosity relaxation time (τ(η), in sec);

[0095] a = the "width" parameter (CY-a parameter);

[0096] n = the fixed final power-law slope, fixed at 2 / 11; and

[0097] ω = angular frequency of oscillatory shear deformation.

[0098] Details of the meaning and interpretation of the CY model and the derived parameters can be found in: C.A. Hieber and H.H. Chiang, Rheol. Acta, 28, 321 (1989); C.A. Hieber and H.H. Chiang, Polym. Eng. Sci., 32, 931 (1992); and R.B. Bird, R.C. Armstrong and O. Hasseger, Dynamics of Polymeric Liquids, Volume 1, Fluid Mechanics, 2nd Edition, John Wiley & Sons (1987); the said documents are each incorporated herein by reference in their entirety.

[0099] Creep adjustment is used to extend the low frequency range of rheological characterization to 10 -4 sec -1 (except for the differential dynamic rheogram constructed without creep adjustment). In a creep test, a constant shear stress σ 0 is applied to the specimen, and the shear strain γ is recorded as a function of the creep time t. Although the time-dependent data generated by creep and creep recovery tests appear different from the frequency-dependent data measured in dynamic frequency sweep tests, as long as the measurements are made in the linear viscoelastic regime, these two sets of experimental data contain the same rheological information, such that the time-dependent creep compliance data can be transformed into frequency-dependent dynamic data, and thus long-term creep measurements can supplement the low frequency data of dynamic frequency sweep measurements. Details of the test methods and analysis can be found in Y.W. Inn and D.C. Rohlfing, “Application of creep test to obtain the linear viscoelastic properties at low frequency range for polyethylene melts” Applied Rheology 22 (2012), which is incorporated herein by reference in its entirety.

[0100] The time-dependent creep compliance J(t) = γ(t) / σ k is modeled using the generalized Voigt model according to the discrete spectrum J 0 of the relaxation time τ k and the zero shear rate viscosity η 0 .

[0101]

[0102] If the discrete delay spectrum accurately describes the compliance data, linear viscoelastic theory allows for a quantitative description of other types of experimental data. For example, the storage and loss compliances are calculated as

[0103]

[0104] From the relationship between the complex modulus and the complex compliance, the storage and loss moduli of the dynamic frequency sweep data can be obtained as

[0105]

[0106] As a simple numerical method for obtaining the discrete delay time spectrum, the Microsoft Excel solver tool can be used by minimizing the following objective function O.

[0107]

[0108] To reliably convert time-dependent creep data into frequency-dependent dynamic data, the frequency range needs to be limited by the test time of the creep measurement. If accurate experimental data can be obtained over the entire creep time range until the creep compliance reaches a steady state, an exact function of the delay spectrum over the entire time scale range can also be calculated. However, it is usually not practical to obtain such data for high molecular weight polymers with very long relaxation times. Creep data only contains information within a finite time range, making the frequency range limited by the duration t N of the creep test, i.e., the effective information of the frequency is in the range of ω > t N -1 and the extrapolated data outside this frequency range may be affected by fitting artifacts.

[0109] For rheological measurements involving creep adjustment, the polymer sample was compression molded at 182 °C for a total of 3 minutes. The sample was melted at a relatively low pressure for 1 minute and then subjected to a high molding pressure for 2 minutes. The molded sample was then quenched in a room temperature press and then 25.4 mm diameter discs were punched out from the molding plate for measurement in a rotational rheometer. Measurements were carried out at 190 °C in 25 mm diameter parallel plates using a controlled stress rheometer (Physica MCR-501, Anton Paar) equipped with an air bearing system. The test chamber of the rheometer was purged with nitrogen to minimize oxidative degradation. After thermal equilibrium, the specimen was squeezed between the plates to a thickness of 1.6 mm and the excess was trimmed. A total of 8 min elapsed between the time of inserting the sample and the start of the test. For dynamic frequency sweep measurements, from 0.0316 to 316 sec -1A small strain (1 - 10%) oscillatory shear in the linear viscoelastic state is applied at the angular frequency. The creep test is carried out for 10,200 sec (170 min) to limit the total test time within 4 hr because the focus is on sample production amount and thermal stability. By converting the time-dependent creep data into frequency-dependent dynamic data, the low-frequency range is extended to 10 -4 rad / sec, which is two orders of magnitude lower than the frequency range of the dynamic test. The Carreau - Yasuda model is used to curve fit the complex viscosity (|η*|) versus frequency (ω) data.

[0110] One of the main concerns in performing the creep test and actually any long-time scale measurement is that the sample does not change significantly during the measurement (which may take several hours to conduct). If the polymer sample is heated for a long time without proper thermal stability (e.g., antioxidants), changes may occur in the polymer, which may have a significant impact on the rheological behavior of the polymer and its characterization. The polymer to be tested should have at least 4 - 5 hr of thermal stability under nitrogen at 190 °C; for example, ethylene polymers containing at least 0.4 wt% antioxidant are found to be stable enough to obtain effective creep compliance data.

[0111] For rheological measurements in parallel plates, the specimen is squeezed between the plates to a thickness of 1.6 mm and then the excess is trimmed. When trimming the sample with a large force in one direction, some residual stress is generated, resulting in strain drift. Therefore, the creep test should be avoided immediately after sample trimming because the residual stress can affect subsequent creep measurements, especially for highly viscoelastic resins with long relaxation times. If the applied stress in the creep test is not large enough, the resulting strain may be very small, such that the creep results may be affected by artifacts of strain drift. To minimize this effect, the sample is trimmed as gently as possible and the creep test is carried out after a waiting time of 2000 sec to allow relaxation of any residual stress.

[0112] The applied stress σ 0 of an appropriate magnitude is important for reliable creep data. The stress σ 0 must be small enough such that the strain will remain within the linear viscoelastic state, and it must be large enough such that the strain signal is strong enough to provide satisfactory data resolution for good accuracy. Although not limited to this, a suitable applied stress is equal to the complex modulus |G*| at a frequency of 0.01 rad / sec multiplied by 0.04.

[0113] At 190 °C at 0.001 sec -1The polymer viscosity under [conditions] (referred to as η(0.001) or eta(0.001)) is determined using a parallel plate geometry with an Anton Paar MCR 501 rheometer.

[0114] The short-chain branch (SCB) content and the short-chain branch distribution (SCBD) across the molecular weight distribution can be determined via an IR5-detected GPC system (IR5-GPC), where the GPC system is a PL220 GPC / SEC system (Polymer Labs, Agilent company) equipped with three Styragel HMW-6E columns (Waters, MA) for polymer separation. A detailed description of the method can be found in the literature (Y. Yu, A Short-Chain Branching Distribution Determination Technique for Polyethylene Using IR5-Detected GPC, Macromolecular Symposia, 2020, 390, 1900014). Briefly, a thermoelectrically cooled IR5 MCT detector (IR5) (Polymer Char, Spain) is connected to the GPC column via a heat transfer line. Chromatographic data are obtained from two output ports of the IR5 detector. First, the analog signal reaches a digital converter from the analog output port before being connected to a computer "A" for molecular weight determination through Cirrus software (Polymer Labs, now Agilent Company) and an integration calibration method using a broad HDPE MARLEX BHB5003 resin (Chevron Phillips Chemical) as a broad molecular weight standard. On the other hand, the digital signal goes directly into computer "B" through a USB cable, where the signal is collected by LabView data collection software provided by Polymer Char. The chromatographic conditions are set as follows: the column oven temperature is 145 °C; the flow rate is 1 mL / min; the injection volume is 0.4 mL; and the polymer concentration is approximately 2 mg / mL, depending on the sample molecular weight. The temperatures of both the heat transfer line and the IR5 detector sample cell are set to 150 °C, while the temperature of the electronics of the IR5 detector is set to 60 °C. The short-chain branch content is determined by an in-house method using the intensity ratio of CH 3 (I CH3 ) to CH 2 (I CH2 ) combined with a calibration curve. The calibration curve is the SCB content (x SCB ) as a function of I CH3 / I CH2Graph of the function of the intensity ratio. To obtain the calibration curve, a set of polyethylene resins (not less than 5 kinds) was used, and their SCB levels were in the range of 0 to about 32 SCB / 1,000 total carbons (SCB standard). All these SCB standards had known SCB levels and flat SCBD curves determined in advance by NMR and solvent gradient fractionation-NMR (SGF-NMR) methods respectively. Using the SCB calibration curve thus established, for the resins fractionated by the IR5-GPC system under exactly the same chromatographic conditions as these SCB standards, a curve of the short-chain branch distribution across the molecular weight distribution was obtained. Using the predetermined SCB calibration curve (i.e., the relationship between the intensity ratio of I CH3 / I CH2 and the SCB content) and the MW calibration curve (i.e., the relationship between the molecular weight and the elution time), the relationship between the intensity ratio and the elution volume was converted into the SCB distribution as a function of the MWD, so as to convert the intensity ratio of I CH3 / I CH2 and the elution time into the SCB content and the molecular weight respectively. Although not tested, it is expected that the number of short-chain branches (SCB) per 1,000 total carbon atoms of the ethylene polymer (or base resin) is greater at Mw (or Mz) than at Mn.

[0115] The metal content (such as the amount of catalyst residue in the ethylene polymer or product) can be determined by ICP analysis on a PerkinElmer Optima 8300 instrument. The polymer sample can be ashed overnight with sulfuric acid in a Thermolyne furnace and then subjected to acid digestion with HCl and HNO 3 (3:1 v:v).

[0116] Examples 1-17

[0117] Figure 1 shows the bimodal molecular weight distribution (relationship between the amount of polymer and the logarithm of the molecular weight) of the polymers in Examples 1-6, Figure 2 shows the bimodal molecular weight distribution of the polymers in Examples 7-12, Figure 3 shows the broad molecular weight distribution of the polymers in Examples 13-17. Table I summarizes the polymer HLMI and certain molecular weight characteristics of the polymers in Examples 1-17, and Table II summarizes certain rheological characteristics of the polymers in Examples 1-12 at 190 °C.

[0118] Example 13 is the base resin (without peroxide) for Examples 14 - 17 and is a wide ethylene copolymer resin (Chevron-Phillips Chemical Company LP) with a nominal 9 HLMI and 0.95 density. Base resin Example 1 (for Examples 1 - 6; nominal 8 - 12 HLMI and 0.955 - 0.96 density) and base resin Example 7 (for Examples 7 - 12; nominal 4.5 - 6.5 HLMI and 0.95 - 0.955 density) are produced using a bis-metallocene catalyst system with an activator-carrier as described below.

[0119] The fluorinated silica-coated alumina activator-carrier used to produce the base resins of Examples 1 and 7 is prepared as follows. Bohemite is obtained from W.R. Grace & Company under the name "alumina A" and has a surface area of approximately 300 m 2 / g, a pore volume of approximately 1.3 mL / g, and an average particle size of approximately 100 microns. The alumina is first calcined in dry air at approximately 600 °C for about 6 hours, cooled to ambient temperature, and then contacted with isopropanol containing tetraethyl orthosilicate to equal 25 wt% SiO 2 . After drying, the silica-coated alumina is calcined at 600 °C for 3 hours. Fluorinated silica-coated alumina (7 wt% F) is prepared by impregnating the calcined silica-coated alumina with an ammonium bifluoride solution in methanol, drying, and then calcining in dry air at 600 °C for 3 hours. Thereafter, the fluorinated silica-coated alumina is collected and stored under dry nitrogen and used without exposure to the atmosphere.

[0120] Pilot plant polymerization is carried out in a 30-gallon slurry loop reactor at a production rate of approximately 33 pounds of polymer per hour. The polymerization work is carried out in a loop reactor (also known as a slurry process) under continuous particle form process conditions by contacting a bis-metallocene solution in isobutane, an organoaluminum solution (triisobutylaluminum, TIBA), and an activator-carrier (fluorinated silica-coated alumina) in a 1 L stirred autoclave with continuous output to the loop reactor. The TIBA and bis-metallocene solutions are fed as separate streams into a T-junction upstream of the autoclave where they contact each other. The activator-carrier is flushed with isobutane at a point after the above T-junction, causing the organoaluminum / metallocene mixture to contact and flow together into the autoclave. The isobutane flush used to transport the activator-carrier to the autoclave is set at a rate that will result in a residence time of approximately 30 minutes in the autoclave. The total flow from the autoclave then enters the loop reactor.

[0121] The ethylene used is polymer grade ethylene obtained from AirGas and purified through an alumina-zeolite adsorbent column (activated in nitrogen at 230 - 290 °C). Polymer grade 1-hexene (obtained from Chevron Phillips Chemical Company) is purified by distillation and passed through an alumina-zeolite adsorbent column activated in nitrogen at 230 - 290 °C. The loop reactor is filled with liquid, has a diameter of 15.2 cm, and a volume of 30 gallons (113.6 liters). Liquid isobutane is used as a diluent. Hydrogen is added at a rate of approximately 0.001 - 0.004 lb / hr to adjust the molecular weight and / or HLMI of the polymer product. The isobutane is polymer grade isobutane (obtained from Enterprise), which is further purified by distillation and then passed through an alumina column (activated in nitrogen at 230 - 290 °C). The cocatalyst TIBA is obtained as a 10 - 12 wt% solution in hydrocarbon and further diluted to 2 wt% in isobutane. The cocatalyst is added at a concentration in the range of 125 ppm based on the weight of the diluent in the polymerization reactor.

[0122] Reactor conditions include a reactor pressure of approximately 590 psig, an ethylene mole % of 11 - 13% (based on the isobutane diluent), and a polymerization temperature of 93 - 100 °C. The reactor is operated to have a residence time of approximately 0.8 - 1.3 hr. The metallocene concentration in the reactor is in the range of approximately 1.5 to 2.5 parts per million (ppm) by weight of the diluent. The activator-carrier (fluorinated silica-coated alumina) is fed to the reactor at a rate of approximately 0.015 - 0.03 pounds per hour. The polymer is removed from the reactor at a rate of approximately 33 lb / hr and passed through a flash chamber and a purge column. Nitrogen is fed to the purge column to ensure that the fluff is hydrocarbon-free. The structures of MET 1 and MET 2 used in Examples 1 and 7 are shown below:

[0123]

[0124] For Example 1, the ratio of MET2:MET1 is 0.67, lb hydrogen / 1000 lb ethylene is 0.063, and lb 1-hexene / lb ethylene is 1.14, while for Example 7, the ratio of MET2:MET1 is 0.63, lb hydrogen / 1000 lb ethylene is 0.031, and lb 1-hexene / lb ethylene is 1.14.

[0125] The ethylene polymers of Examples 2-6, 8-12, and 14-17 were prepared by blending the corresponding base resins of Examples 1, 7, and 13 with a masterbatch containing a polymeric carrier resin and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane. The amount of peroxide groups was in the range of 10 to 300 ppm of peroxide groups by weight, based on the weight of the base resin, as shown in Tables I and II. The blend of the base resin and the peroxide masterbatch was compounded using a twin screw extrusion system (ZSK-300) and then pelletized to form the ethylene polymers of Examples 2-6, 8-12, and 14-17.

[0126] Certain properties of the polymers of Examples 1-17 are summarized in Tables I and II. Many of the peroxide-treated polymers have an HLMI value of less than 12 g / 10 min, an Mw value of 200,000 to 550,000 g / mol, an Mn value of 18,000 to 48,000 g / mol, a CY-a parameter of less than 0.12, a tanδ at 0.1 sec of 0.5 to 0.9 degrees -1 and a tanδ at 100 sec of 0.5 to 0.75 degrees -1 and a viscosity at 0.001 sec of 1.3×10 6 to 1×10 7 Pa-sec, such as in Examples 4-6 and Examples 9-12. Generally, as the amount of peroxide increases, the zero shear viscosity, relaxation time, and viscosity at 0.001 sec -1 increase, while the CY-a parameter and the tanδ at 0.1 sec -1 decrease. -1

[0127] Figure 4 show the rheological differences between Examples 2-6 and the baseline (no peroxide) of Example 1, Figure 5 show the rheological differences between Examples 8-12 and the baseline (no peroxide) of Example 7, and Figure 6 show the rheological differences between Examples 14-17 and the baseline (no peroxide) of Example 13. Figure 6 Show the expected effect of peroxide treatment on viscosity, particularly the steady increase in viscosity in the low shear region as the amount of peroxide added increases. In contrast, Figure 4-5 the effect of peroxide treatment shown in Figure 1-2 is unexpected and, while not wishing to be bound by theory, may be the result of different amounts of chain scission and crosslinking in the very high molecular weight fraction of the polymer - also note

[0128] The blow molding evaluations of Examples 1-6 were carried out on a Sterling blow molding machine having the following specifications. These particular equipment and processing conditions were chosen because the blow molding performance and characteristics obtained in this way are typically representative of those obtained from larger commercial scale blow molding operations. The extruder screw diameter is 3″, the L / D ratio is 24:1, the drive motor is a 75HP DC drive, and the maximum plasticizing capacity is approximately 350 lb of polyethylene / hr. The extruder is equipped with a dynamicso pressure indicator, has four heated zones with air cooling, and a smooth barrel with liquid cooling in the feed zone.

[0129] The maximum injection capacity (shot capacity) of the accumulator head (FIFO design) is 10 lb, and the maximum and minimum die bushing diameters are 8″ and 1″ respectively, where the diameter converges from 1″ to 3 1 / 2 ″ and diverges from 4″ to 8″. The blow molding machine is also equipped with a 100-point MACO programming device.

[0130] For Examples 1-6, all extruder and head zones were set at 390°F. The mold is a 9-gallon bottle (Fremont plastic mold, 42″ circumference), and a 4.5″ diverging die with a 30-degree landing angle was used. A constant ejection speed was used. The mold temperature was 50 - 60°F. The timer was set for a 0.5 sec blow delay, 0 sec pre-blow, and a 0.25 sec clamp close delay. The air pressure was approximately 90 psig. The minimum wall thickness of the part was in the range of 45 - 50 mils, and the die gap was 0.196″. Parts were produced at an extruder speed of 30 RPM and a blow molding time of 90 sec.

[0131] The weight of the product produced (part weight) was recorded, and the width of the splash plate at the bottom of the product (flat bottom) was measured. The die swell of the polymer can be quantified by the part weight (grams), while the melt strength of the polymer can be quantified by the flat bottom (inches). The melt strength of the polymer was compared by the hang-up time test using a 0.089″ die gap and an extruder speed of 20 RPM. The extruded parison was hung on the die; when the parison was hung on the die, the extruder speed became zero. The time from the end of injection to the parison leaving the bushing was recorded as the hang-up time.

[0132] The blow molding evaluations of Examples 7 - 12 were conducted on a Kautex KB - 25 blow molding machine with the following specifications. These particular equipment and processing conditions were chosen because the blow molding properties and characteristics obtained in this way are typically representative of those obtained from larger commercial - scale blow molding operations. The extruder screw diameter is 80 mm, the L / D ratio is 20:1, the drive motor is a 60 HP DC drive, and the maximum plasticizing capacity is approximately 330 lb of polyethylene / hr. The extruder is equipped with a dynicso pressure indicator, three heated zones with air cooling, and a liquid - cooled slotted liner in the feed zone for processing high - molecular - weight polyethylene pellets and powder resins.

[0133] The maximum injection capacity of the accumulator head (FIFO design) is 8.5 lb, the maximum and minimum die bushing diameters are 8″ and 2″ respectively, where the die bushing converges from 2″ to 3 1 / 2 ″ and diverges from 4″ to 8″. The blow molding machine is also equipped with a 100 - point Hunkar programmer.

[0134] For Examples 7 - 12, all extruder and head zones were set at 405°F. The mold was a 9 - gallon bottle (Fremont plastic mold), and a 4.5″ diverging die with a 30 - degree landing angle was used. A constant extrusion pressure was used. The mold temperature was 50 - 60°F. The timer was set for a 0.5 - sec blow delay, 0 - sec pre - blow, and 0 - sec mold - close delay. The air pressure was 90 psig. The minimum wall thickness of the part was in the range of 45 - 50 mils, and the die gap was 0.196″. Parts were produced at an extruder speed of 30 RPM and a blow molding time of 90 sec.

[0135] The weight of the product produced (part weight) was recorded, and the width of the splash plate at the bottom of the product (flat bottom) was measured. The die swell of the polymer can be quantified by the part weight (grams), and the draw - down of the polymer can be quantified by the flat bottom (inches). The melt strength of the polymer was compared by the hang - up time test using a 0.089″ die gap and an extruder speed of 20 RPM. The extruded parison was hung up on the die. The time from the end of injection to the parison leaving the liner was recorded as the hang - up time.

[0136] Table III summarizes the blow molding properties of the polymers of Examples 1 - 12, Figure 7 showing the draw - down and die - swell characteristics of Examples 2 - 6 compared to Example 1 (without peroxide), and Figure 8Shows the die swell and re - swell characteristics of Examples 8 - 12 compared to Example 7 (without peroxide). Unexpectedly, the tables and figures show the decoupling of die swell and re - swell. In particular, the die swell (quantified by the flat bottom) of Examples 2 - 6 compared to Example 1 is virtually the same, and the die swell of Examples 8 - 12 compared to Example 7 is virtually the same, while the re - swell (quantified by the part weight) surprisingly increases with the increase in peroxide loading. Thus, the ratio of part weight (grams) to flat bottom (inches) for Examples 5 - 6 and Examples 11 - 12 is much larger when compared to Example 1 and Example 7 without peroxide treatment, respectively. Additionally and advantageously, peroxide treatment increases the melt strength of the polymer, as reflected by the increase in hang - on - die time with increasing peroxide addition.

[0137]

[0138]

[0139]

[0140] The present invention has been described above by reference to numerous aspects and specific embodiments. Those skilled in the art will envision many variations based on the foregoing detailed description. All such obvious variations are within the full scope of the appended claims. Other aspects of the present invention may include, but are not limited to, the following aspects (the aspects are described as "comprising", but alternatively, may "consist essentially of" or "consist of"):

[0141] Aspect 1. An ethylene polymer having the following items (or characterized by the following):

[0142] A high load melt index less than or equal to 12 g / 10 min;

[0143] A weight - average molecular weight in the range of 200,000 to 550,000 g / mol;

[0144] A number - average molecular weight in the range of 18,000 to 48,000 g / mol;

[0145] A CY - a parameter less than or equal to 0.12;

[0146] A tanδ at 0.1 sec in the range of 0.5 to 0.9 degrees -1 ;

[0147] A tanδ at 100 sec in the range of 0.5 to 0.75 degrees -1 ; and

[0148] At 1.3×106 to 1×10 7 Pa-sec within 0.001 sec -1 under the viscosity of

[0149] Aspect 2. The polymer as defined in Aspect 1, wherein the HLMI of the ethylene polymer is within any of the ranges disclosed herein, for example, less than or equal to 10, less than or equal to 8, 1 to 12, 1 to 10, 1 to 8, 2 to 12, 2 to 10 g / 10 min, etc.

[0150] Aspect 3. The polymer as defined in Aspect 1 or 2, wherein the Mw of the ethylene polymer is within any of the ranges disclosed herein, for example, 200,000 to 500,000 g / mol, 250,000 to 550,000 g / mol, 250,000 to 500,000 g / mol, 250,000 to 475,000 g / mol, 275,000 to 550,000 g / mol, 275,000 to 475,000 g / mol, etc.

[0151] Aspect 4. The polymer as defined in any of the preceding aspects, wherein the CY-a parameter of the ethylene polymer is within any of the ranges disclosed herein, for example, less than or equal to 0.11, less than or equal to 0.1, less than or equal to 0.08, less than or equal to 0.06, 0.01 to 0.12, 0.01 to 0.1, 0.01 to 0.08, 0.01 to 0.06, etc.

[0152] Aspect 5. The polymer as defined in any of the preceding aspects, wherein the tanδ of the ethylene polymer at 0.1 sec -1 is within any of the ranges disclosed herein, for example, 0.5 to 0.85 degrees, 0.5 to 0.8 degrees, 0.55 to 0.9 degrees, 0.55 to 0.85 degrees, 0.6 to 0.9 degrees, 0.6 to 0.85 degrees, 0.6 to 0.8 degrees, etc.

[0153] Aspect 6. The polymer as defined in any of the preceding aspects, wherein the tanδ of the ethylene polymer at 100 sec -1 is within any of the ranges disclosed herein, for example, 0.5 to 0.72 degrees, 0.5 to 0.7 degrees, 0.52 to 0.75 degrees, 0.52 to 0.72 degrees, 0.52 to 0.7 degrees, 0.55 to 0.75 degrees, 0.55 to 0.72 degrees, etc.

[0154] Aspect 7. The polymer as defined in any of the preceding aspects, wherein the viscosity of the ethylene polymer at 0.001 sec -1 is within any of the ranges disclosed herein, for example, 1.3×10 6to 5.5×10 6 Pa-sec, 1.3×10 6 to 5×10 6 Pa-sec, 1.5×10 6 to 1×10 7 Pa-sec, 1.5×10 6 to 6×10 6 Pa-sec, 1.5×10 6 to 5×10 6 Pa-sec, 2×10 6 to 6×10 6 Pa-sec, 2×10 6 to 5×10 6 Pa-sec, etc.

[0155] Aspect 8. The polymer as defined in any one of the foregoing aspects, wherein the viscosity of the ethylene polymer at 100 sec -1 is within any of the ranges disclosed herein, such as 1700 to 3300 Pa-sec, 1800 to 3200 Pa-sec, 1900 to 3100 Pa-sec, 2000 to 3000 Pa-sec, etc.

[0156] Aspect 9. The polymer as defined in any one of the foregoing aspects, wherein the zero-shear viscosity of the ethylene polymer is within any of the ranges disclosed herein, such as 1×10 8 to 1×10 30 Pa-sec, 1×10 8 to 1×10 28 Pa-sec, 1×10 10 to 1×10 30 Pa-sec, 1×10 10 to 1×10 27 Pa-sec, 1×10 12 to 1×10 27 Pa-sec, etc.

[0157] Aspect 10. The polymer as defined in any one of the foregoing aspects, wherein the density of the ethylene polymer is within any of the ranges disclosed herein, such as 0.935 to 0.965, 0.94 to 0.965, 0.945 to 0.965, 0.94 to 0.96, 0.945 to 0.96 g / cm 3 etc.

[0158] Aspect 11. The polymer as defined in any one of the foregoing aspects, wherein the ethylene polymer has an inverse comonomer distribution. For example, the number of short-chain branches (SCBs) per 1000 total carbon atoms of the polymer is greater at Mw than at Mn, the number of SCBs per 1000 total carbon atoms of the polymer is greater at Mz than at Mw, the number of SCBs per 1000 total carbon atoms of the polymer is greater at Mz than at Mn, and so on.

[0159] Aspect 12. The polymer as defined in any one of the foregoing aspects, wherein the Mp of the ethylene polymer is within any of the ranges disclosed herein, such as 60,000 to 110,000 g / mol, 65,000 to 105,000 g / mol, 70,000 to 100,000 g / mol, etc.

[0160] Aspect 13. The polymer as defined in any one of the foregoing aspects, wherein the Mn of the ethylene polymer is within any of the ranges disclosed herein, such as 20,000 to 46,000 g / mol, 22,000 to 46,000 g / mol, 20,000 to 42,000 g / mol, 22,000 to 40,000 g / mol, etc.

[0161] Aspect 14. The polymer as defined in any one of the foregoing aspects, wherein the Mw / Mn ratio of the ethylene polymer is within any of the ranges disclosed herein, such as 6.5 to 20, 7 to 17, 7.5 to 15, 8 to 13, etc.

[0162] Aspect 15. The polymer as defined in any one of the foregoing aspects, wherein the Mz / Mw ratio of the ethylene polymer is within any of the ranges disclosed herein, such as 4 to 9, 4 to 8, 4.5 to 7.5, 5 to 7, etc.

[0163] Aspect 16. The polymer as defined in any one of the foregoing aspects, wherein the relaxation time (τ η ) of the ethylene polymer is within any of the ranges disclosed herein, such as 5×10 3 to 1×10 25 sec, 6×10 3 to 1×10 23 sec, 1×10 5 to 1×10 25 sec, 1×10 5 to 1×10 23 sec, 1×10 7 to 1×10 23 sec, etc.

[0164] Aspect 17. The polymer as defined in any one of the foregoing aspects, wherein the ratio of die swell to extrudate swell (die swell: extrudate swell) of the ethylene polymer is within any of the ranges disclosed herein, such as 200 to 280, 210 to 270, 230 to 280, 230 to 270, etc., and / or the die hold-up time of the ethylene polymer is within any of the ranges disclosed herein, such as at least 40 sec, at least 50 sec, at least 100 sec, etc.

[0165] Aspect 18. The polymer as defined in any one of the foregoing aspects, wherein the ethylene polymer has a bimodal molecular weight distribution.

[0166] Aspect 19. The polymer as defined in any one of the foregoing aspects, wherein the ethylene polymer is a single reactor product, e.g., not a post-reactor blend of two polymers having different molecular weight characteristics, for example.

[0167] Aspect 20. The polymer as defined in any one of the foregoing aspects, wherein the ethylene polymer comprises an ethylene / α-olefin copolymer.

[0168] Aspect 21. The polymer as described in any one of the foregoing aspects, wherein the ethylene polymer comprises an ethylene homopolymer, an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, and / or an ethylene / 1-octene copolymer.

[0169] Aspect 22. The polymer as defined in any one of the foregoing aspects, wherein the ethylene polymer comprises an ethylene / 1-hexene copolymer.

[0170] Aspect 23. The polymer as described in any one of the foregoing aspects, wherein the ethylene polymer independently contains less than 0.1 ppm (by weight), less than 0.08 ppm, less than 0.05 ppm, less than 0.03 ppm, etc. of Mg, V, Ti, or Cr.

[0171] Aspect 24. The polymer as described in any one of the foregoing aspects, wherein the ethylene polymer further comprises at least one additive selected from antioxidants, acid scavengers, anti-caking additives, slip additives, colorants, fillers, processing aids, UV inhibitors, etc., or any combination thereof.

[0172] Aspect 25. An article (e.g., a blow molded product) comprising the ethylene polymer as defined in any one of the foregoing aspects.

[0173] Aspect 26. An article comprising an ethylene polymer as defined in any one of Aspects 1-24, wherein the article is an agricultural film, automotive part, bottle, chemical container, drum, fiber or fabric, food packaging film or container, food service article, fuel tank, geomembrane, household container, liner, molded product, medical device or material, outdoor storage product, outdoor play equipment, pipe, sheet or tape, toy, or traffic barrier, etc.

[0174] Aspect 27. A method for preparing an ethylene polymer, comprising contacting a base resin with a peroxide compound to produce an ethylene polymer as defined in any one of Aspects 1-24.

[0175] Aspect 28. The method according to Aspect 27, wherein the base resin is contacted with peroxide groups in an amount of 10 to 500 ppm, 25 to 400 ppm, 50 to 350 ppm, etc., based on the weight of the base resin.

[0176] Aspect 29. The method as defined in Aspect 27 or 28, wherein the contacting step comprises melt-processing a blend (or mixture) of the base resin and the peroxide compound at any of the melt-processing temperatures disclosed herein (e.g., in the range of 120 to 300 °C, in the range of 150 to 250 °C, in the range of 175 to 225 °C, etc.).

[0177] Aspect 30. The method as defined in Aspect 29, wherein the melt-processing is carried out in a twin-screw extrusion system.

[0178] Aspect 31. The method as defined in Aspect 29, wherein the melt-processing is carried out in a single-screw extrusion system.

[0179] Aspect 32. The method as defined in any one of Aspects 27-31, wherein the peroxide compound comprises any suitable peroxide compound or any peroxide compound disclosed herein, such as 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, tert-butyl cumyl peroxide, n-butyl-4,4'-di(tert-butylperoxy)valerate, etc., or any combination thereof.

[0180] Aspect 33. The method as defined in any one of Aspects 27-32, wherein the base resin has the following (or is characterized by the following):

[0181] A high load melt index in the range of 2 to 40 g / 10 min;

[0182] A weight average molecular weight in the range of 250,000 to 550,000 g / mol;

[0183] CY-a parameter in the range of 0.12 to 0.3;

[0184] tanδ at 0.1 sec within the range of 0.8 to 1.05 degrees -1 ;

[0185] tanδ at 100 sec within the range of 0.4 to 0.6 degrees -1 ; and

[0186] Viscosity at 0.001 sec within the range of 1×10 5 to 3×10 6 Pa-sec. -1

[0187] Aspect 34. The method as defined in aspect 33, wherein the HLMI of the base resin is within any of the ranges disclosed herein, such as 2 to 20, 2 to 12, 4 to 40, 4 to 20, 4 to 15, 4 to 12 g / 10 min, etc.

[0188] Aspect 35. The method as defined in aspect 33 or 34, wherein the Mw of the base resin is within any of the ranges disclosed herein, such as 250,000 to 500,000 g / mol, 250,000 to 475,000 g / mol, 300,000 to 550,000 g / mol, 300,000 to 500,000 g / mol, etc.

[0189] Aspect 36. The method as defined in any one of aspects 33 - 35, wherein the CY-a parameter of the base resin is within any of the ranges disclosed herein, such as 0.12 to 0.25, 0.13 to 0.3, 0.13 to 0.25, 0.14 to 0.25, etc.

[0190] Aspect 37. The method as defined in any one of aspects 33 - 36, wherein the tanδ of the base resin at 0.1 sec -1 is within any of the ranges disclosed herein, such as, 0.5 to 0.85 degrees, 0.8 to 1 degree, 0.83 to 1.05 degrees, 0.83 to 1 degree, 0.85 to 1.05 degrees, 0.85 to 1 degree, etc.

[0191] Aspect 38. The method as defined in any one of aspects 33 - 37, wherein the tanδ of the base resin at 100 sec -1 is within any of the ranges disclosed herein, such as 0.4 to 0.58 degrees, 0.4 to 0.55 degrees, 0.45 to 0.6 degrees, 0.45 to 0.58 degrees, 0.45 to 0.55 degrees, etc.

[0192] Aspect 39. The method as defined in any one of aspects 33 - 38, wherein the viscosity of the base resin at 0.001 sec -1 is within any of the ranges disclosed herein, such as 1×10 5 to 2×10 6 Pa-sec, 1×10 5 to 1.8×10 6 Pa-sec, 8×10 5 to 3×10 6 Pa-sec, 8×10 5 to 2×10 6 Pa-sec, 8×10 5 to 1.8×10 6 Pa-sec, etc.

[0193] Aspect 40. The method as defined in any one of aspects 33 - 39, wherein the zero-shear viscosity of the base resin is within any of the ranges disclosed herein, such as 1×10 6 to 1×10 9 Pa-sec, 1×10 6 to 2×10 8 Pa-sec, 4×10 6 to 1×10 9 Pa-sec, 4×10 6 to 2×10 8 Pa-sec, etc.

[0194] Aspect 41. The method as defined in any one of aspects 33 - 40, wherein the density of the base resin is within any of the ranges disclosed herein, such as 0.935 to 0.965, 0.94 to 0.965, 0.945 to 0.965, 0.94 to 0.96, 0.945 to 0.96 g / cm 3 etc.

[0195] Aspect 42. The method as defined in any one of aspects 33 - 41, wherein the base resin has an inverse comonomer distribution. For example, the number of short-chain branches (SCB) per 1000 total carbon atoms of the polymer is greater at Mw than at Mn, the number of SCB per 1000 total carbon atoms of the polymer is greater at Mz than at Mw, the number of SCB per 1000 total carbon atoms of the polymer is greater at Mz than at Mn, and so on.

[0196] Aspect 43. The method as defined in any one of Aspects 33 - 42, wherein the Mp of the base resin is within any of the ranges disclosed herein, such as 60,000 to 110,000 g / mol, 65,000 to 105,000 g / mol, 65,000 to 100,000 g / mol, etc.

[0197] Aspect 44. The method as defined in any one of Aspects 33 - 43, wherein the Mn of the base resin is within any of the ranges disclosed herein, such as 18,000 to 48,000 g / mol, 20,000 to 42,000 g / mol, 20,000 to 38,000 g / mol, etc.

[0198] Aspect 45. The method as defined in any one of Aspects 33 - 44, wherein the Mw / Mn ratio of the base resin is within any of the ranges disclosed herein, such as 9 to 20, 11 to 19, 12 to 18, 13 to 16, etc.

[0199] Aspect 46. The method as defined in any one of Aspects 33 - 45, wherein the Mz / Mw ratio of the base resin is within any of the ranges disclosed herein, such as 4 to 9, 5 to 8, 5 to 7.5, 6 to 8, etc.

[0200] Aspect 47. The method as defined in any one of Aspects 33 - 46, wherein the ratio of die swell to draw down (die swell: draw down) of the base resin is within any of the ranges disclosed herein, such as 150 to 225, 180 to 225, 170 to 200, etc.

[0201] Aspect 48. The method as defined in any one of Aspects 33 - 47, wherein the hang - up time of the base resin is within any of the ranges disclosed herein, such as 10 to 45 sec, 15 to 45 sec, 20 to 45 sec, etc.

[0202] Aspect 49. The method as defined in any one of Aspects 33 - 48, wherein the base resin has a bimodal molecular weight distribution.

[0203] Aspect 50. The method as defined in any one of Aspects 33 - 49, wherein the base resin is a single reactor product, e.g., not a post - reactor blend of two polymers having different molecular weight characteristics.

[0204] Aspect 51. The method as defined in any one of Aspects 33 - 50, wherein the base resin comprises an ethylene / α - olefin copolymer.

[0205] Aspect 52. The method as defined in any one of aspects 33 - 51, wherein the base resin comprises an ethylene homopolymer, an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, and / or an ethylene / 1-octene copolymer.

[0206] Aspect 53. The method as defined in any one of aspects 33 - 52, wherein the base resin comprises an ethylene / 1-hexene copolymer.

[0207] Aspect 54. The method as defined in any one of aspects 33 - 53, wherein the base resin independently contains less than 0.1 ppm (by weight), less than 0.08 ppm, less than 0.05 ppm, less than 0.03 ppm, etc. of Mg, V, Ti, or Cr.

[0208] Aspect 55. The method as defined in any one of aspects 33 - 54, wherein the base resin further comprises at least one additive selected from antioxidants, acid scavengers, anti-caking additives, slip additives, colorants, fillers, processing aids, UV inhibitors, etc., or any combination thereof.

Claims

1. An ethylene polymer having: an HLMI of less than or equal to 12 g / 10 min as determined at 190 °C with a weight of 21.6 kg according to ASTM D1238; an Mw in the range of 200,000 to 550,000 g / mol; an Mn in the range of 18,000 to 48,000 g / mol; a CY-a parameter of less than or equal to 0.12 as determined at 190 °C; tanδ within the range of 0.5 to 0.9 degrees at 0.1 sec -1 below; tanδ within the range of 0.5 to 0.75 degrees at 100 sec -1 and; At 1.3×10 6 to 1×10 7 Pa-sec, the viscosity at 190 °C and 0.001 sec -1 is as follows. wherein the ethylene polymer is prepared by a process comprising contacting a base resin with a peroxide compound, wherein the amount of the peroxide compound is 10 to 500 ppm by weight of peroxide groups based on the weight of the base resin.

2. The polymer according to claim 1, wherein: the HLMI is in the range of 1 to 10 g / 10 min; the Mw is in the range of 250,000 to 500,000 g / mol; the Mn is in the range of 22,000 to 46,000 g / mol; the CY-a parameter is in the range of 0.01 to 0.1; The tanδ at 0.1 sec -1 is in the range of 0.6 to 0.85 degrees; The tanδ at 100sec -1 is in the range of 0.52 to 0.72 degrees; and The viscosity at 190°C and 0.001 sec -1 is in the range of 1.5×10 6 to 6×10 6 Pa-sec.

3. The polymer according to claim 2, wherein the ethylene polymer comprises an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, an ethylene / 1-octene copolymer, an ethylene homopolymer, or a combination thereof.

4. The polymer according to claim 2, wherein the polymer has a density in the range of 0.94 to 0.96 g / cm 3 3.

5. The polymer according to claim 1, wherein the polymer has: at 1×10 8 to 1×10 30 Pa-sec for the zero shear viscosity (η 0 ); and from 5×10 3 to 1×10 25 sec for the relaxation time (τ η ).

6. The polymer according to claim 1, wherein the polymer comprises an ethylene / α-olefin copolymer.

7. The polymer according to claim 6, wherein the polymer independently contains less than 0.1 ppm by weight of Mg, V, Ti, and Cr.

8. The polymer according to claim 7, wherein the polymer has: at 1×10 10 to 1×10 27 Pa-sec for the zero shear viscosity (η 0 ); and Within 1×10 5 to 1×10 23 sec relaxation time (τ η ).

9. The polymer according to claim 1, wherein: the polymer comprises an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, an ethylene / 1-octene copolymer, an ethylene homopolymer, or a combination thereof; and the polymer further contains an additive selected from antioxidants, acid scavengers, anti-caking additives, slip additives, colorants, fillers, processing aids, ultraviolet inhibitors, or any combination thereof.

10. The polymer according to claim 9, wherein the polymer has: Viscosity at 100 sec within the range of 1700 to 3300 Pa-sec; and -1 and an Mp in the range of 65,000 to 105,000 g / mol.

11. The polymer according to claim 9, wherein the polymer has: an Mw / Mn ratio in the range of 7 to 17; and an Mz / Mw ratio in the range of 4.5 to 7.

5.

12. The polymer according to claim 9, wherein: the HLMI is in the range of 1 to 10 g / 10 min; the Mw is in the range of 250,000 to 500,000 g / mol; the Mn is in the range of 22,000 to 46,000 g / mol; the CY-a parameter is in the range of 0.01 to 0.1; The tanδ at 0.1sec -1 is in the range of 0.6 to 0.85 degrees; The tanδ within 100 sec -1 is in the range of 0.52 to 0.72 degrees; and The viscosity at 190°C and 0.001 sec -1 is in the range of 1.5×10 6 to 6×10 6 Pa-sec.

13. The polymer according to claim 1, wherein the polymer has: a ratio of die swell to draw down in the range of 200 to 280; and a hang-up time of at least 40 sec.

14. The polymer according to claim 1, wherein the polymer has a number of short chain branches (SCBs) per 1000 total carbon atoms at Mw that is greater than at Mn, or a number of SCBs per 1000 total carbon atoms at Mz that is greater than at Mn, or both.

15. An article comprising the polymer according to claim 1.

16. An article comprising the polymer according to claim 7.

17. An article comprising the polymer according to claim 12.

18. A method for preparing an ethylene polymer, which comprises: contacting a base resin with a peroxide compound to produce the ethylene polymer, wherein the ethylene polymer is characterized by: a high load melt index (HLMI) of less than or equal to 12 g / 10 min as determined at 190 °C according to ASTM D1238 at a weight of 21.6 kg; a weight average molecular weight (Mw) in the range of 200,000 to 550,000 g / mol; a number average molecular weight (Mn) in the range of 18,000 to 48,000 g / mol; a CY-a parameter of less than or equal to 0.12 as determined at 190 °C; tanδ within the range of 0.5 to 0.9 degrees at 0.1 sec -1 or less; tanδ at 100 sec within the range of 0.5 to 0.75 degrees -1 downward; and At 1.3×10 6 to 1×10 7 Pa-sec, the viscosity at 190 °C and 0.001 sec -1 is as follows wherein, based on the weight of the base resin, the amount of the peroxide compound is 10 to 500 ppm by weight of peroxide groups.

19. The method according to claim 18, wherein: the step of contacting the base resin with the peroxide compound comprises melt processing a mixture of the base resin and the peroxide compound in a twin screw extrusion system.

20. The method according to claim 18, wherein: the base resin comprises an ethylene homopolymer, an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, an ethylene / 1-octene copolymer, or a combination thereof; and the base resin is produced using a bis-metallocene catalyst system.

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