CN118019797A

CN118019797A - Polyethylene glycol-based polymer processing aids

Info

Publication number: CN118019797A
Application number: CN202280065275.6A
Authority: CN
Inventors: N·罗科; M·A·利弗; D·万霍维根
Original assignee: ExxonMobil Chemical Patents Inc
Current assignee: ExxonMobil Chemical Patents Inc
Priority date: 2021-09-30
Filing date: 2022-09-22
Publication date: 2024-05-10
Also published as: CN118055973A; CN118019793A; CN118647667A; CN118019789A; CN118019796A; CN118019794A

Abstract

Provided herein are polymer compositions comprising a polymer and a polyethylene glycol (PEG) -based Polymer Processing Aid (PPA) composition. The polyethylene glycol may have a molecular weight of less than 40,000 g/mol. The polymer may be a C ₂-C₆ olefin homopolymer or a copolymer of two or more C ₂-C₂₀ alpha-olefins, and may have a Melt Index Ratio (MIR) of 20 or less. The polymer composition may further comprise a fatty acid metal salt. The polymer composition is preferably free or substantially free of fluorine, including PPA based on fluoropolymers.

Description

Polyethylene glycol-based polymer processing aids

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application 63/261,908 entitled "Fluorine-Free Polymer Processing Aids [ fluoropolymer processing aid ]" filed on 9 months of 2021, and also claims the benefit of U.S. provisional application 63/266,782 entitled "Fluorine-Free Polymer Processing Aids [ fluoropolymer processing aid ]" filed on 14 months of 2022, and also claims the benefit of U.S. provisional application 63/309,871 entitled "Fluorine-Free Polymer Processing Aids Including Polyethylene Glycols [ fluoropolymer processing aid comprising polyethylene glycol ]" filed on 7 months of 2022, and also claims the benefit of U.S. provisional application 63/267,640 entitled "Fluorine-Free Polymer Processing Aids Including Polyethylene Glycols [ fluoropolymer processing aid comprising polyethylene glycol ]" filed on 14 months of 2022, and also claims the benefit of U.S. provisional application 63/309,859 entitled "Fluorine-Free Polymer Processing Aid Blends [ fluoropolymer processing aid blend ]" filed on 14 months of 2022, and further claims the benefit of 2022, and further claims the benefit of end-35,35, and further claims the benefit of U.S. provisional application 63/309,859 entitled "Fluorine-Free Polymer Processing Aids Including Polyethylene Glycols [ fluoropolymer processing aid ]" filed on 14, and claims the benefit of 2022, and further claims the benefit of end-35,35, and further claims the benefit of end-35,35,35 to the benefit of U.S. provisional application 3,35,35,35, the entire contents of these applications are incorporated herein by reference.

Technical Field

The present disclosure relates to additives for polyolefin polymers (e.g., polyethylene), as well as to the polymers themselves, to methods of making the same, and to articles made therefrom.

Background

There is a great need for polyolefin polymer compositions for many applications including various films (such as cast films, shrink films, and blown films), sheets, membranes (membranes) such as geomembranes, sacks, pipes (e.g., heat resistant polyethylene (PE-RT) pipes, utility pipes, and gas distribution pipes), rotomolded parts, blow molded flexible bottles or other containers, and various other blow molded/extruded articles such as bottles, barrels, cans, and other containers. These applications are typically made of, for example, polyethylene polymers.

Polyolefin polymers are most commonly produced and sold as pellets which are formed during post-polymerization reactor finishing (e.g., extrusion of the polymer product in an at least partially molten state, followed by pelletization). As part of this finishing process, additives are typically blended into the polymer product such that the polymer pellets comprise the polymer itself and one or more additives.

Common additives, particularly for polymers intended for use as films, sacks and other similar articles, such as polyethylene, include Polymer Processing Aids (PPA) which help to make the pellets easier to handle in downstream manufacturing processes (e.g., extrusion, rolling, blow molding, casting, etc.). In addition, a sufficient amount of PPA helps to eliminate melt fracture in films made from polymer pellets. This is especially true for polymer pellets that exhibit relatively high viscosity during extrusion. Melt fracture is a mechanically induced melt flow instability, which occurs, for example, at the exit of an extrusion die and typically under high shear rate conditions. Small holes, linear and annular die geometries are among those that may induce melt fracture. The mechanical states describing PE melt fracture vary, but all appear as very rough polymer surfaces, which persist as the polymer crystallizes. As is common in the blown film industry, a series of rough shark-skin-like patterns (typically with characteristic dimensions on the order of from mm to cm) appear on the film surface, and they depend on both the flow characteristics and rheology of the polyolefin polymer (e.g., polyethylene).

Melt fracture can adversely affect film properties, distort clarity, and reduce thickness uniformity. Thus, polymer grades prone to melt fracture, as previously mentioned, typically rely on PPA.

The most common PPA is or includes a fluoropolymer (fluoropolymer). However, it would be desirable to find alternative PPAs that do not contain fluoropolymers and/or fluorine, while maintaining the effectiveness of fluoropolymer-based PPAs in preventing melt fracture.

Some references that may be interesting in this regard include: U.S. Pat. nos. 10,982,079;10,242,769;10,544,293;9,896,575;9,187,629;9,115,274;8,552,136;8,455,580;8,728,370;8,388,868;8,178,479;7,528,185;7,442,742;6,294,604;5,015,693; and 4,540,538; U.S. patent publication nos. 2005/007044, 2008/0132654, 2014/0182882, 2014/024474, 2015/0175785, 2017/0342245, 2020/0325614; and WO 2020/146351;WO 2011/028206、CN 104558751、CN 112029173、KR 10-2020-0053903、CN 110317383、JP 2012009754 A、WO 2017/077455、CN 108481855、CN 103772789.

Disclosure of Invention

The present disclosure relates to polymer compositions, methods of making the same, and articles comprising and/or made from these polymer compositions. Of particular interest, the polymer composition may be a polyolefin composition, such as a polyethylene composition. The polymer composition may also include PPA that is free or substantially free of fluorine; and, similarly, the polymer composition may be free or substantially free of fluorine. In this context, "substantially free of (substantially free)" allows trace amounts (e.g., 10ppm or less, preferably 1ppm or less, such as 0.1ppm or less) of fluorine, for example as an impurity, but well below the amount of fluorine atoms that would be intentionally included in the polymer composition via such additives (e.g., about 100ppm by mass of the polymer product under typical conditions including such additives). In various embodiments, the polymer composition may be, for example, a polymer pellet; polymer melt (as would be formed in an extruder such as a compounding extruder); reactor grade polymer particles and/or polymer slurry; or other forms of polymer compositions containing the PPA and optionally one or more other additives.

The present disclosure also relates to films and/or other end use articles made from such polymer compositions, and in particular instances may relate to cast or blown films, preferably blown films. Thus, the polyolefin compositions (e.g., polymer pellets) of the various embodiments and/or films or other articles made therefrom (e.g., blown films) are themselves free or substantially free of fluorine (or at least free or substantially free of fluorine-based PPA). Fluorine-based PPA as used herein is a polymer processing aid or other fluorine-containing polymer additive.

The present inventors have found that polyethylene glycol (PEG) alone can advantageously replace fluorine-based PPA in polyolefin compositions for many polymers, especially polyethylene polymers, having low Melt Index (MI) and/or medium to high Melt Index Ratio (MIR). Thus, the PPA based on PEG may comprise at least 80wt% (based on the total mass of PPA), more preferably at least 90wt%, or at least 99wt%, such as at least 99.9 or 99.99wt% PEG; or PPA may consist of or consist essentially of PEG. The molecular weight of the PEG may be less than 40,000g/mol, such as in the range of 1,500 to 35,000g/mol, such as 5,000 to 12,000g/mol, or 5,000 to 20,000g/mol.

However, it has also been found that certain polymers, particularly polyethylene polymers having relatively higher MI and lower MIR, may benefit from PPA blend counterparts used in conjunction with PEG. Thus, in some embodiments, when PPA is used with a polymer (e.g., a polyethylene polymer) having an MIR of 20 or less (and optionally an MI of 1.0 or greater), PPA comprises a blend of PEG and PPA blend partner. PEG is preferably consistent with PEG described above, and PPA blend partner is preferably selected from fatty acid metal salts (e.g., fatty acid zinc salts, such as zinc stearate). The PEG and PPA blend partners may be used in PPA compositions in amounts ranging from 30:70 to 70:30 (PEG: PPA blend partners).

It has further been found that PPA blend partners such as fatty acid metal salts can provide the additional benefit of increasing the melting point of PPA compositions (as compared to PPA compositions having PEG alone) making handling of the compositions easier. Alternatively, PEG masterbatches can be utilized to simplify processing without the use of PPA blend partners.

Thus, in some embodiments, the invention extends to a process for producing two or more polymer products, the process comprising producing a first polymer having a MIR of greater than 20 at a first time; and producing a second polymer at a second time different from the first time, the second polymer having a MIR of 20 or less. Using PPA comprising PEG (preferably consisting of or consisting essentially of PEG or a PEG masterbatch) in the first polymer to finish it (e.g., via compounding extrusion) into a first polymer product (e.g., a first polymer pellet); and using PPA comprising a PEG and PPA blend partner (e.g., a fatty acid metal salt) in the second polymer to finish it (e.g., via compounding extrusion) to a second polymer product (e.g., a second polymer pellet).

The PEG (or PPA composition comprising PEG, and optionally PPA blend partner such as a fatty acid metal salt) may be present in the polymer composition in an amount ranging from about 200ppm to about 15000ppm, more preferably from about 300ppm to about 2000ppm, or from about 600ppm to about 1200ppm, based on the mass of polymer in the polymer composition. As noted, other additives optionally may also be present in the polymer composition (e.g., antioxidants, stabilizers such as UV stabilizers, catalyst neutralizers, and other additives known in the polymerization arts).

Further, the present disclosure provides, in some aspects, a masterbatch of PEG (and optionally with other additives) that can be configured as a PPA composition. The masterbatch comprises a carrier resin and one or more PEGs each having a Mw of less than 40,000 g/mol.

Drawings

Fig. 1 is a schematic diagram conceptually illustrating stripes of melt fracture in a blown film during extrusion and stripes with areas of eliminated melt fracture.

Fig. 2 is a graph showing the% melt fracture over time observed for certain test films produced using various PPA compositions associated with the examples.

Fig. 3 is a graph showing% melt fracture over time observed for other test films produced using various PPA compositions associated with the examples.

Fig. 4 is a graph showing the% melt fracture over time observed for additional test films produced using various PPA compositions associated with the examples.

Fig. 5 is a graph showing the% melt fracture over time observed for yet additional test films produced using the various PPA compositions associated with the examples.

Fig. 6 is a graph showing% melt fracture over time observed for another set of test films produced using various PPA compositions associated with the examples.

Fig. 7 is a graph showing% melt fracture over time observed for another set of test films produced using various PPA compositions associated with the examples.

Fig. 8 is a graph showing the% melt fracture over time observed for an additional set of test films produced using various PPA compositions associated with the examples.

Detailed Description

Definition of the definition

For purposes of this disclosure, various terms are defined as follows.

The term "polyethylene" refers to a polymer having at least 50wt% ethylene derived units, such as at least 70wt% ethylene derived units, such as at least 80wt% ethylene derived units, such as at least 90wt% ethylene derived units, or at least 95wt% ethylene derived units, or 100wt% ethylene derived units. Thus, the polyethylene may be a homopolymer or copolymer, including a terpolymer, having one or more other monomer units. The polyethylenes described herein can, for example, comprise at least one or more other olefins and/or comonomers.

"Olefins", alternatively referred to as "olefins", are straight, branched, or cyclic compounds of carbon and hydrogen having at least one double bond. For the purposes of this specification and the appended claims, when a polymer or copolymer is referred to as comprising an olefin, the olefin present in such polymer or copolymer is the polymerized form of the olefin. For example, when the copolymer is said to have an "ethylene" content of 50wt% to 55wt%, based on the weight of the copolymer, it is understood that the monomer units in the copolymer are derived from ethylene in the polymerization reaction, and that the derived units are present at 50wt% to 55 wt%. "Polymer" has two or more monomer units that are the same or different. "homopolymer" is a polymer having the same monomer units. A "copolymer" is a polymer having two or more monomer units that are different from each other. "terpolymer" is a polymer having three monomer units that differ from one another. Accordingly, as used herein, the definition of copolymer includes terpolymers, etc. As used herein to refer to monomer units, "different" indicates that the monomer units differ from each other by at least one atom or are isomerically different.

The term "alpha-olefin" refers to an olefin having a terminal carbon-carbon double bond in its structure R ¹R²C＝CH₂, where R ¹ and R ² can independently be hydrogen or any hydrocarbyl group; if R ¹ is hydrogen and R ² is alkyl. "Linear alpha-olefins" are alpha-olefins in which R ¹ is hydrogen and R ² is hydrogen or linear alkyl. For purposes of this disclosure, ethylene should be considered an alpha-olefin.

As used herein, the term "extrusion" and grammatical variations thereof refers to a process that includes forming a polymer and/or polymer blend into a melt, such as by heat and/or shear forces, and then forcing the melt out of a die in a form or shape, such as in a film or in pelletized strands. Almost any type of equipment will be suitable for extrusion, such as single or twin screw extruders, or other melt blending devices as known in the art and may be equipped with a suitable die. It should also be understood that extrusion may be performed as part of the polymerization process (particularly in the final processing portion of such a process) as part of forming a polymer product (e.g., polymer pellets); or extrusion may be performed as part of a process for forming an article, such as a film, from polymer pellets (e.g., by at least partially melting and extruding the pellets through a die to form a sheet, particularly when combined with blowing air, such as in a blown film forming process). In the context of the present disclosure, extrusion in the final processing portion of the polymerization process may be referred to as compounding extrusion, and typically involves feeding additive plus additive-free (reactor grade) polymer into an extruder; while polymer extrusion to make articles (e.g., polymer pellet extrusion to make films) is conceptually "downstream" (e.g., at a later point in time, after the polymer product has been formed (including extrusion by compounding)) and typically involves feeding optional additives plus the polymer containing additives into the extruder.

"Finishing" as referred to herein with respect to the polymerization process refers to post-polymerization reactor processing steps taken to form a finished polymer product, such as a polymer pellet, one example of a finishing process being compounding extrusion as just discussed. As one of ordinary skill will recognize, finishing differs from, and conceptually precedes, further processing of the finished polymer product into an article, such as a film.

A "PEG-based PPA composition" is a polymer processing aid composition that contains at least 20wt% polyethylene glycol (based on the total mass of the PPA composition).

"Polymer composition" refers to a composition containing a polymer. The polymer composition may be in any form. Some examples include: reactor grade forms (e.g., pellets) containing polymer; a molten or at least partially molten composition comprising a polymer and one or more additives that has undergone or is about to undergo a final processing process (such as in a compounding extrusion process), which may be referred to as a pre-form; in the form of a finished polymer product, such as polymer particles containing a polymer and any additives (e.g., PPA); or in the form of a finished polymer product, such as polymer particles that have undergone a process of mixing with additives (e.g., via coextrusion, melt blending, or other processing), such as in the case where the polymer is being extruded to form a film or other polymer-containing article.

Polymer

In various embodiments, the polymer composition comprises one or more polymers, preferably polyolefin polymers. Examples include homopolymers (e.g., homopolymers of C ₂ to C ₁₀ alpha-olefins, preferably C ₂ to C ₆ alpha-olefins). Specific examples of homopolymers include homo-polyethylene and homo-polypropylene (hPP). In the case of homo-polyethylene, such polymers may be produced, for example, by high pressure free radical polymerization, typically yielding a highly branched ethylene homopolymer-commonly referred to as LDPE (Low Density polyethylene), having a density of less than 0.945g/cm ³, typically 0.935g/cm ³ or less, such as in the range of 0.900, 0.905, or 0.910g/cm ³ to 0.920, 0.925, 0.927, 0.930, 0.935, or 0.945g/cm ³. All polymer density values are determined according to ASTM D1505 unless otherwise indicated herein. The samples were molded according to procedure C of ASTM D4703-10a and conditioned for 40 hours according to ASTM D618-08 (23 ℃ C.+ -. 2 ℃ C. And 50.+ -. 10% relative humidity) prior to testing.

In another example, ethylene monomer may be polymerized via known gas phase, slurry phase, and/or liquid phase polymerizations (e.g., using a catalyst such as a chromium-based catalyst, or a single site catalyst such as a Ziegler-Natta (Ziegler-Natta) and/or metallocene catalyst, all of which are well known in the polymerization art and not further discussed herein). In the case of producing a more highly linear ethylene homopolymer (e.g., gas phase or slurry phase polymerization using any of the above catalysts), it may be referred to as HDPE (high density polyethylene), typically having a density of 0.945g/cm ³ or greater, such as in the range of 0.945 to 0.970g/cm ³.

Still further examples of polymers include copolymers of two or more C ₂ to C ₄₀ alpha-olefins, such as C ₂ to C ₂₀ alpha-olefins, such as ethylene-alpha-olefin copolymers, or propylene-alpha-olefin copolymers (e.g., propylene-ethylene copolymers, or propylene-ethylene-diene terpolymers, sometimes referred to as EPDM or PEDM). Specific examples contemplated herein include copolymers of ethylene and one or more C ₃ to C ₂₀ alpha-olefin comonomers, such as C ₄ to C ₁₂ alpha-olefin comonomers (wherein 1-butene, 1-hexene, 1-octene, or mixtures of two or more thereof are preferred in various embodiments). Ethylene copolymers (e.g., copolymers of ethylene and one or more C ₃ to C ₂₀ alpha-olefins) may comprise at least 80wt%, or 85wt%, such as at least 90, 93, 94, 95, or 96wt% (e.g., in the range from a low point of 80, 85, 90, 91, 92, 93, 94, 95, 96, or 97wt% to a high point of 94, 95, 95.5, 96, 96.5, 97, 97.5, or 98wt%, based on the total amount of ethylene-derived units and comonomer-derived units), with ethylene-derived units in an amount ranging from any of the foregoing low values to any of the foregoing high values (provided that the high point is greater than the low point) being contemplated. For example, the ethylene copolymer may comprise 94 or 95wt% to 97 or 98wt% ethylene derived units based on the total amount of ethylene derived units and comonomer derived units. The balance of the copolymer (based on ethylene derived units and comonomer derived units) consists of comonomer derived units. For example, comonomer units (e.g., C ₂ to C ₂₀ α -olefin derived units, such as units derived from butene, hexene, and/or octene) can be present in the ethylene copolymer from a low point of 2, 2.5, 3, 3.5, 4, 4.5, 5, or 6wt% to a high point of 3,4, 5, 6, 7, 8, 9, 10, 15, or 20wt%, with the proviso that the high point is greater than a low value, where a range from any of the aforementioned low points to any of the aforementioned high points is contemplated.

For ethylene-based, propylene-based, or other alpha-olefin-based copolymers, several suitable comonomers have been noted, although other alpha-olefin comonomers are contemplated in various embodiments. For example, the alpha-olefin comonomer may be linear or branched, and two or more comonomers may be used if desired. Examples of suitable comonomers include linear C ₃-C₂₀ alpha-olefins (such as butene, hexene, octene as already noted) and alpha-olefins having one or more C ₁-C₃ alkyl branches, or aryl groups. Examples may include propylene; 3-methyl-1-butene; 3, 3-dimethyl-1-butene; 1-pentene; 1-pentene having one or more methyl, ethyl or propyl substituents; 1-hexene with one or more methyl, ethyl or propyl substituents; 1-heptene having one or more methyl, ethyl or propyl substituents; 1-octene with one or more methyl, ethyl or propyl substituents; 1-nonene having one or more methyl, ethyl or propyl substituents; ethyl, methyl or dimethyl substituted 1-decene; 1-dodecene; and styrene. It should be understood that the list of comonomers described above is merely exemplary and is not intended to be limiting. In some embodiments, the comonomer comprises propylene, 1-butene, 1-pentene, 4-methyl-l-pentene, 1-hexene, 1-octene, and styrene.

In particular embodiments, the polymer may comprise or may be an ethylene copolymer (in accordance with those described above). The ethylene copolymer may be produced in a gas phase, slurry phase or liquid phase polymerization, and some particularly preferred ethylene copolymers may be produced in a gas phase or slurry phase polymerization. Specific examples are Linear Low Density Polyethylene (LLDPE), i.e., copolymers of ethylene and one or more alpha-olefins polymerized in the presence of one or more single site catalysts, such as one or more Ziegler-Natta catalysts, one or more metallocene catalysts, and combinations thereof. Such LLDPE may have a density in the range of from a low point of 0.900, 0.905, 0.907, 0.910g/cm ³ to a high point of 0.920, 0.925, 0.930, 0.935, 0.940, or 0.945g/cm ³. LLDPE can be distinguished from the LDPE described above in several respects, many of which are well known in the art, including the degree of branching (sometimes more precisely referred to as long chain branching) in the polymer produced, with substantially less (usually little, if any) long chain branching being noted for LLDPE. In particular embodiments, the polymer of the polymer composition is or includes a metallocene-catalyzed LLDPE (mLLDPE).

Additionally or alternatively, in some embodiments, the density of the polymer may be in the range of 0.905 to 0.945g/cm ³, such as in the range of from a low point of any of 0.905, 0.907, 0.908, 0.910, 0.911, 0.912, 0.913, 0.914, or 0.915g/cm ³ to a high point of any of 0.916, 0.917, 0.918, 0.919, 0.920, 0.924, 0.926, 0.930, 0.935, 0.940, or 0.945g/cm ³, where a range from any of the aforementioned low points to any of the aforementioned high points (e.g., 0.910 to 0.925 or 0.935g/cm ³, such as 0.912 to 0.925, or 0.915 to 0.918g/cm ³) is contemplated herein. In yet other embodiments, the polymer may have a higher density (e.g., HDPE) with a density in the range of 0.945g/cm ³ to 0.970g/cm ³.

In addition, the rheological characteristics of the polymer may affect the preferred PEG-based PPA composition to be employed in the polymer composition to form the finished polymer product. In general, PPA compositions are preferably used in polymers having a melt index (MI or I ₂, measured according to ASTM D1238 at 190 ℃ under a load of 2.16 kg) in the range of from 0.1, 0.2, or 0.5g/10min to 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 4.0, or 5.0g/10min, inclusive of any low point to any high point, or less, preferably 2.5g/10min or less. Melt Index Ratio (MIR) is another polymer characteristic that may be of interest in this regard. MIR is defined herein as the ratio of High Load Melt Index (HLMI) (measured according to ASTM D1238 at 190 ℃, 21.6kg load) to melt index, or HLMI/MI. The polymers of some embodiments may have a MIR typically in the range of 10, 12 or 15 to 19, 20, 21, 22, 25, 27, 30, 35, 40, 45, 50, 60, 65, 70, 75, 80, 85, 90, 95, or 100. In particular embodiments, PPA compositions consisting of or consisting essentially of PEG (or PEG concentrate, discussed below) are used for polymers (especially ethylene-based polymers, such as copolymers of ethylene and C ₃ to C ₁₂ α -olefins) having a MIR in the high point range of greater than 20, such as greater than 20, or 21, 22, 23, 25, 27, or 30 to 35, 40, 45, 50, 60, 65, 70, 75, 80, 85, 90, 95, or 100. Optionally, the MI in such polymers may be less than 1.5g/10min, such as 1.0g/10min or less (e.g., in the range of any of 0.1, 0.2, or 0.5g/10min to 1.0; or to 1.1, 1.2, 1.3, 1.4, or less than 1.5g/10 min).

On the other hand, it is preferred to add PPA blend partners (e.g., fatty acid metal salts such as zinc stearate) to the polymer of PPA compositions for treating MIR in the range of 20 or less, such as 5, 10, 12 or 15 to 17, 18, 19 or 20. Optionally, such polymers may also have a melt index in the range of 1.0g/10min or greater, such as in the range of 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5 or 3.0 to 2.0, 2.2, 2.3, 2.5, 3.0, 3.5, 4.0, 4.5 or 5.0g/10min (with the proviso that the high end is greater than the low end of any of the foregoing ranges from the low end to any of the foregoing high ends being contemplated).

In addition, such polymers optionally may have a Broad Orthogonal Composition Distribution (BOCD), as described, for example, in paragraphs 0045-0046, 51 and 53 of U.S. patent application Ser. No. 17/66158, entitled "Blends of recycled resins with Metallocene-catalyzed polyolefins ]" and filed on 5/4 of 2022, which descriptions are incorporated herein by reference. In particular, such polymers may be copolymers of ethylene and a C ₃ to C ₂₀ α -olefin, such as a C ₃ to C ₁₂ α -olefin, such as 1-butene, 1-hexene and/or 1-octene, having from 80 to 99wt% of units derived from ethylene and the balance of units derived from one or more α -olefin comonomers. Any of a variety of characteristic quantifications may be associated with BOCD properties, such as one or more of the following: (i) A T ₇₅-T₂₅ value of 5 to 10 (where T ₂₅ is the temperature in degrees celsius at which 25% of the eluted polymer is obtained and T ₇₅ is the temperature in degrees celsius at which 75% of the eluted polymer is obtained, fractionation by Temperature Rising Elution (TREF)); (ii) A Composition Distribution Breadth Index (CDBI) of less than about 40%, such as less than about 35%; and (iii) a first peak and a second peak in the comonomer distribution analysis, wherein the first peak has a maximum at a log (MW) value of 4.0 to 5.4 and a TREF elution temperature of 70 ℃ to 100 ℃ and the second peak has a maximum at a log (MW) value of 5.0 to 6.0 and a TREF elution temperature of 40 ℃ to 60 ℃. The CDBI and TREF methods used to determine these characteristics are described in paragraphs 37 and 44 of U.S. patent application Ser. No. 17/661958. Additionally or alternatively, the copolymer may be determined to have BOCD properties by the method described in paragraphs [0048] - [0054] of WO 2022/120321 and fig. 2a, which description is incorporated herein by reference, especially with respect to the description of fig. 2a and the plot of comonomer wt% versus log (MW) derived using gas chromatography (GPC) illustrates BOCD when the plot exhibits a positive slope, as quantified by the comonomer slope index values described in the incorporated paragraphs of WO 2022/120321.

Thus, in some embodiments, the disclosure includes a method for producing two or more polymer compositions, the method comprising: (a) Producing a first polymer having a Melt Index Ratio (MIR) of greater than 20 (and optionally a Melt Index (MI) of 1.0 or less) at a first time; (b) Combining the first polymer with a PEG-based PPA composition comprising one or more PEG and having substantially no fatty acid metal salt to form a first polymer product; (c) Producing a second polymer having a MIR of 20 or less (and optionally a melt index greater than or equal to 1.0g/10min; further optionally BOCD) at a second time different from the first time; and (d) combining the second polymer with a PEG-based PPA composition comprising one or more PEG and one or more fatty acid salts to form a second polymer product. Conveniently, such a method may require a continuous process as part of the production campaign; for example, the methods can include continuously feeding a base PEG-based PPA composition comprising one or more PEG and being substantially free of fatty acid metal salts to a compounding extruder; continuously co-feeding a first polymer to a compounding extruder during a first period of time during feeding, and obtaining a first polymer product; and continuously adding one or more metal salts to the PEG-based PPA composition fed to the compounding extruder during a second time period (after the first time period) during the feeding, while continuously co-feeding a second polymer to the compounding extruder, and obtaining a second polymer product. The process may further continue after the second period of time for a third period of time at the beginning of which the addition of the one or more metal salts to the feed of the PEG-based PPA composition is stopped such that the feed of the PEG-based PPA composition substantially free of fatty acid metal salts to the compounding extruder is resumed as a continuous feed, during which a third polymer having a MIR of greater than 20 (and optionally a MI of 1.0g/10min or less) is continuously co-fed into the compounding extruder and a third polymer product is obtained. In this way, the PPA blend partner is only configured at any time during the time period required for processing (e.g., finishing) of the polymer (the rheology of which requires the PPA blend partner), thereby providing a customized process and conserving resources.

PEG-based polymer processing aids, including PEG and PPA blend partner components, are discussed in more detail below.

PEG-based polymer processing aids and suitable PEG

As shown, the polymer composition further comprises a PEG-based PPA composition. The PEG-based PPA composition may comprise at least 20wt% PEG, such as at least 30wt% or at least 40wt% PEG. In particular embodiments, the PEG-based PPA may consist of or consist essentially of PEG or a PEG masterbatch (where "consisting essentially of … …" in this context allows for up to 1wt%, more preferably 0.5wt% or less, most preferably 0.1wt% or less of impurities, where the impurities preferably do not include fluorine or any fluorine-containing compound). In other embodiments, the PEG-based PPA composition may comprise PEG at a loading of 20, 30 or 40 to 60, 70, 80, or 90wt% (based on the total mass of the PPA composition), and one or more PPA blend partners at a loading in the range of 10, 20, 30, or 40wt% to 60, 70, or 80wt% (based on the total mass of the PPA composition, where any of the foregoing low-to any of the foregoing high-end ranges are contemplated).

Notably, PEG is a component in some known fluoropolymer-based PPAs (see, e.g., WO 2020/146351), and higher molecular weight PEG (commonly referred to as polyethylene oxide or PEO, see below for more details) has been suggested as one of the other components in other PPAs, e.g., metal salts or alkyl sulfates of specific acids (see, e.g., US 2017/0342245). However, the inventors have found that certain low molecular weight polyethylene glycol species can be used as PPA, and that for most polymers PEG can be formulated without other components, especially without fluorine-based components and/or inorganic components such as the metal salts described above. Thus, the PPA of the present disclosure comprises at least 80wt% PEG or PEG masterbatch, more preferably at least 90wt% PEG or PEG masterbatch, such as at least 95wt% or at least 99wt% PEG or PEG masterbatch; alternatively, PPA can be said to consist of or consist essentially of PEG or a PEG masterbatch (where "consisting essentially of … …" in this context means that no other components are intended to be included, but trace amounts, e.g., 100ppm or less, preferably 50ppm or less, or even 10 or 1ppm or less, of impurities are allowed, and further where such impurities do not include fluorine or fluorine-containing compounds). More generally, the inventors have determined suitable processing conditions, suitable PEG species (based on, for example, molecular weight), and suitable loadings of the PEG-based PPA composition in the polymer composition, which alone or together can overcome many challenges to incorporate PEG into the polymer composition. For example, PEG has a much lower melting temperature than many polymers (e.g., polyethylene homopolymers or copolymers), and thus may begin to bead during an attempt to mix the ingredient with such polymers that have a higher melting point than PEG. This phenomenon can be alleviated or exacerbated depending on the size (molecular weight) of the PEG and/or the desired loading of the PEG-based PPA composition in the polymer; and may affect proper mixing. Furthermore, as a generally hydrophilic compound, incorporation of PEG into a generally more hydrophobic polymer composition may present some challenges, requiring careful examination of the appropriate molecular weight ranges, amounts, and methods of incorporating PEG-based PPA into the polymer composition, particularly when the PEG-based PPA composition comprises a significant amount of PEG or PEG masterbatch (80 wt% or more, 90wt% or more, 99wt% or more, or substantially all based on the mass of the PPA composition).

Polyethylene glycol or PEG, as used herein, refers to a polymer represented as H- (O-CH ₂-CH₂)_n -OH, where n represents the number of repetitions of the O-CH ₂-CH₂ (oxyethylene) moiety; n can vary widely because the molecular weight of PEG varies widely, e.g., for lower molecular weight polyethylene glycols (about 1500 g/mol), n can be about 33, for higher molecular weight polyethylene glycols (about 10,000 g/mol) ranging up to about 227, such as about 454 for about 20,000g/mol molecular weight PEG, and 908 for about 40,000 molecular weight PEG, and this value is even higher for higher molecular weight PEG species.

It should also be noted that PEG may equivalently be referred to as polyethylene oxide (PEO) or Polyoxyethylene (POE). Sometimes in industry terminology, PEG is the designation for relatively lower molecular weight species (e.g., molecular weight of 20,000g/mol or less), while polyethylene oxide or PEO is used for higher molecular weight species (e.g., greater than 20,000 g/mol). However, for the purposes of the present application, references to polyethylene glycol or PEG should not be construed as implying only specific molecular weight ranges, except where molecular weight ranges are explicitly indicated. That is, the term polyethylene glycol or PEG may be used herein to refer to polymers having the structure H- (O-CH ₂-CH₂)_n -OH (where n is such that the molecular weight of the polymer is less than 20,000 g/mol), and also to refer to polymers where n is such that the molecular weight of the polymer is greater than 20,000g/mol, such as in the range of 20,000 to 40,000 g/mol.

As used herein, PEG "molecular weight" refers to weight average molecular weight (Mw) as determined by Gel Permeation Chromatography (GPC), and PEG "molecular weight distribution" or MWD refers to the ratio of Mw to number average molecular weight (Mn), i.e., mw/Mn. The PEG composition used in PPA may advantageously have a narrow MWD, such as in a range from a low point of any of about 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5 to a high point of any of about 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, or 3.0, with the proviso that the high end is greater than the low end (e.g., 1.0 to 2.0, or 1.0 to 1.5, such as 1.0 to 1.2, or even 1.0 to 1.1) in view of the range from any of the aforementioned low ends to any of the aforementioned high ends. For example, PEG compositions having MWD of about 1 to 1.1 or 1.2 may be particularly useful. However, obtaining such uniform length polymer chains (i.e., narrow MWD) can be expensive; thus, commercially available PEG compositions may have a broad MWD value (e.g., ranging from 1 to 3, 4, 5, or even higher). Accordingly, such PEG compositions are also within the scope of the present invention. These PEG compositions can still be suitably used as PPA, possibly (but not necessarily) compensated for by increasing the PEG loading of such broader MWD PEGs (e.g.700-1400 ppm, as opposed to as low as 400-700ppm for narrower MWD PEGs). The PPA loading based on PEG will be discussed in more detail below.

In embodiments employing narrow MWD PEG, the Mw value of the PEG will generally be relatively close to unity (e.g., within 10%) with Mn; regardless of the difference between the two (Mw and Mn), however, mw should be controlled as a preferred "molecular weight" measurement for purposes of this disclosure. It is also noted that many commercial PEG compounds include nominal molecular weights (e.g., "PEG 3K" or "PEG 10K" indicating nominal 3,000g/mol and 10,000g/mol molecular weights, respectively). Likewise, the Mw of the PEG should be controlled relative to any inverse nominal index.

Polyethylene glycols suitable for use in the PEG-based PPA herein may generally include PEG of various molecular weights, possibly including PEG having a Mw ranging from as low as 500g/mol to as high as 200,000g/mol (e.g., low points of any of 500, 600, 700, 800, 900, 1000, 3000, 5000, 7000, or 7500g/mol to high points of 40000, 50000, 60000, 75000, 80000, 90000, 100000, 125000, 150000, 175000, or 200000g/mol, where ranges of any low end to any high end are contemplated).

However, in certain embodiments, particularly preferred PEGs are those having a molecular weight of less than 40,000 g/mol; such as in the range from a low point of any of 500、600、700、800、900、1000、1500、2000、2500、3000、3500、4000、4500、5000、5500、6000、7000、8000、8500、9000、9500、10000、12500、 and 15000g/mol to a high point of any of 7000、7500、8000、8500、9000、9500、10000、10500、11000、11500、12000、12500、15000、20000、22000、25000、30000、35000、39000、 and 39500g/mol, provided that the high end is greater than the low end, and wherein a range from any of the foregoing low ends to any of the foregoing high ends is generally contemplated (e.g., 1,500 to 35,000g/mol, or 5,000 to 20,000g/mol, such as 5,000 to 12,000g/mol or 6,000 to 12,000 g/mol). Specific higher or lower subranges may also be suitable (e.g., PEG with a Mw of 1,500 to 5,500g/mol, or PEG with a Mw of 5,000 to 12,000g/mol, or PEG with a Mw of 10,000 to 20,000g/mol, or PEG with a Mw of 15,000 to 25,000g/mol, or PEG with a Mw of 25,000 to 35,000 g/mol).

In addition, it is contemplated that blends of a plurality of the foregoing PEG compounds can form suitable PPAs. For example, the PEG-based PPA may comprise at least 90wt%, preferably at least 99wt%, of a blend of two or more polyethylene glycols, such as any two or more of the following: a first PEG having a molecular weight in the range of 3,000 to 7,000 g/mol; a second PEG having a molecular weight in the range of 5,000 to 12,000 g/mol; a third PEG having a molecular weight in the range of 10,000 to 20,000 g/mol; and a fourth PEG having a molecular weight in the range of 20,000 to 40,000g/mol, provided that the first, second, third and fourth PEGs of such blends each have a molecular weight different from the other polyethylene glycol or polyethylene glycols of these blends. Also, in some embodiments, higher molecular weight PEG may be included in such blends (e.g., one or more PEG having a molecular weight greater than 40,000 g/mol).

However, as shown, it is contemplated that many embodiments of the PEG-based PPA compositions as described herein do not include polyethylene glycol (or polyethylene oxide) having a molecular weight greater than 40,000 g/mol. That is, it is preferred that all or substantially all of the polyethylene glycol of the polymer composition have less than 40,000g/mol; such as less than 35,000g/mol, or less than 33,000g/mol, or less than 22,500g/mol, or less than 20,000g/mol, or less than 12,000g/mol, such as less than 10,000 g/mol. In this context, "substantially all" means that a small amount (50 ppm or less, more preferably 10ppm or less, such as 1ppm or less) of higher molecular weight PEG can be included without losing the effect of including predominantly the lower molecular weight PEG described herein. Equivalently, no or substantially no PEG having a molecular weight greater than 40,000g/mol is present in the polymer composition. It is believed that the interest in lower molecular weight PEG generally enables the reduction of the loading of PEG-based PPA to achieve the desired melt fracture elimination on most polymer grades that may experience melt fracture when forming blown films. Similarly, lower molecular weight PEG is believed to diffuse more rapidly to the surface of polymeric materials extruded in, for example, blown film processes than higher molecular weight PEG species; thus, lower molecular weight PEG species will typically result in faster elimination of melt fracture in the blown film (and thus reduced off-spec production). However, while lower molecular weight PEG has the advantages described above, it is contemplated that higher molecular weight PEG (e.g., mw >40,000 g/mol) may be suitable for certain polymer grades in certain circumstances; accordingly, it is contemplated that such higher molecular weight PEG may be included in polymer compositions that remain within the spirit and scope of some embodiments of the present invention.

Commercially available examples of suitable polyethylene glycols, particularly those having lower molecular weights, include those available from basf corporationE 1500；E 3400；E 4000；E 6000；E8000; andE9000 polyethylene glycol (where these numbers represent the nominal molecular weight of PEG); and also includes Carbowax ^TM8000、Carbowax^TMSentry^TM 8000 NF EP available from Dow corporation (Dow).

Measurement of molecular weight component (movement)

Unless otherwise indicated, the distribution and components of molecular weight were determined by using an Agilent 1260 Infinity II multi-detector GPC/SEC system equipped with multiple serially connected detectors, including Differential Refractive Index (DRI) detectors, viscometer detectors, dual angle Light Scattering (LS) detectors, and UV diode array detectors. Two AGILENT PLGEL- μm hybrid-C columns plus guard columns were used to provide polymer separation. THF solvent or equivalent solvent from Sigma-Aldrich, containing 250ppm of the antioxidant Butylhydroxytoluene (BHT) was used as the mobile phase. The nominal flow rate was 1.0ml/min and the nominal sample volume was 25 μl. The entire system, including column, detector and tube, was run at 40 ℃. Column calibration was performed by using twenty-three narrow standards of polystyrene ranging from 200 to 4,000,000 g/mol.

The data from any combination of DRI, light scatter and viscometer detectors was processed using Agilent multi-detector GPC data analysis software to obtain information about polymer properties. Here, the light scattering MW is calculated by combining the concentration measured by DRI and the Rayleigh ratio (Rayleigh ratio) measured by LS in each elution volume slice, plus a detector calibration constant and a polymer parameter such as refractive index increment (dn/dc). For the poly (ethylene glycol) samples used in this patent, dn/dc was determined to be about 0.07ml/g in THF solvent.

Amount and polymer characteristics of PEG-based PPA

The polyethylene glycol (or PEG-based PPA) may be disposed in the polymer composition in an amount of at least 200ppm, such as at least 250ppm, at least 300ppm, at least 400ppm, at least 500ppm, or at least 600 ppm. For example, it may be configured in an amount ranging from a low point of any of 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 900, 950, 1000, 1100, 1200, 1250, and 1500ppm to a high point of any of 400、500、600、700、800、900、1000、1100、1200、1300、1400、1500、1600、1700、1800、1900、2000、2500、3000、3500、4000、4500、5000、7500、10000、12500 and 15000ppm, with the proviso that the high end is greater than the low end (e.g., 300 to 15,000ppm, such as 300 to 2,000ppm, or 500 to 1500ppm, such as 500 to 1200ppm, or 600 to 1200 ppm) taking into account the range of any of the foregoing low points to any of the foregoing high points. In various embodiments, ppm values may be applicable to polyethylene glycol included in the polymer composition; or a PEG-based PPA composition included in the polymer composition. In addition, the ppm values of the polyethylene glycol (or PEG-based PPA composition) described herein, as well as any other additives described herein, are based on the mass of the polymer composition (i.e., including the polymer plus PPA, as well as any and all other additives in the polymer composition), unless specifically stated otherwise. The amount of PPA in the polymer composition can most easily be determined using the mass balance principle (e.g., PPA amount is determined as the mass of PPA added to the polymer composition divided by (the mass of PPA plus the mass of polymer plus the mass of any other additives blended together to form the polymer composition)). NMR analysis can be used to determine the PPA content of an already mixed polymer composition (e.g., polymer pellets comprising polymer and PPA), but in case of a difference between the two methods (mass balance and NMR), a mass balance method should be used.

Furthermore, the inventors of the present invention have unexpectedly found that PEG molecular weight can affect optimal loading. In particular, higher molecular weight PEG eliminates melt fracture faster at lower loadings than lower molecular weight PEG; and at the same time, the higher loading of higher molecular weight PEG may in fact result in slower melt portion elimination in films made with polymer compositions comprising PEG-based PPA. On the other hand, it is evident that lower molecular weight PEG variants may require higher loadings, while lower loadings of these PEG variants may require too long to eliminate melt fracture (or not eliminate completely). The boundary between these opposite trends appears to be in the molecular weight range of 7,500-11,000g/mol, with the 7,500-11,000g/mol region representing the transition region, with both trends being less pronounced. Thus, PEG having a Mw of less than 7,500g/mol is generally best used at higher loadings (e.g., 1000, 1100, or 1200ppm to 2000 or higher ppm), while PEG having a Mw of 11,000g/mol or more is better used at medium or low loadings (e.g., 200 to 500, 600, 700, 800, 900, 1000, 1100, or 1200ppm based on the mass of the polymer). However, the situation is somewhat complicated, so the solution is not necessarily as simple as the preference for higher molecular weight PEG. In particular, as described herein, certain polymer grades may require higher PEG loadings (regardless of molecular weight) because polymer rheology also affects PEG performance in eliminating melt fracture of blown films made from the polymer. Thus, the use of higher molecular weight PEG may lead to misregions of varying grade specific loadings, where unexpectedly over-loaded PEG may adversely affect performance in some cases, and improve performance in other cases.

Generally applicable to these trends, we first see a set of embodiments employing lower molecular weight PEG in combination with relatively higher loading levels. That is, the polymer composition of some embodiments comprises PEG or a PEG masterbatch (or more generally, a PEG-based PPA composition), wherein the Mw of one or more PEGs of the polymer composition is less than 7,500g/mol (e.g., in the range of 95g/mol to less than 7,500g/mol, such as 95, 100, 500, or 600g/mol to 1000, 3000, 4000, 5000, 6000, 7000, 7250, or less than 7500 g/mol); and further wherein the total amount of PEG in the polymer composition is in the low point range of any of 800, 850, 900, 950, or 1000ppm to the high point range of any of 1200, 1250, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2500, 3000, 3500, 4000, 4500, or 5000ppm, wherein ranges of any of the foregoing low ends to any of the foregoing high ends (e.g., 800 or 900ppm to 2000ppm, such as 950ppm to 1700ppm or 1000ppm to 1500 ppm) are also contemplated.

Second, there is a set of embodiments that employ relatively higher molecular weight PEG in combination with relatively lower loading levels. That is, the polymer composition may comprise PEG (or PEG-based PPA), wherein the Mw of one or more PEG of the polymer composition is greater than 11,000g/mol (e.g., in the range of greater than 11,000g/mol to 35,000 or 40,000g/mol, such as from a low end of any of >11000, 11500, 12000, 12500, or 14000 to a high end of any of 15000, 16000, 17500, 20000, 25000, 30000, 35000, or 40000 g/mol); and further wherein the total amount of PEG in the polymer composition is in the low point range of any of 200, 250, or 300ppm to the high point range of 300, 350, 400, 425, 450, 500, 600, 700, 750, 800, 1000, or 1100 ppm. Thus, specific examples are shown wherein one or more PEG in the polymer composition has a Mw in the range of 11000 to 20000g/mol and the total amount of PEG in the polymer composition is in the range of 200 to 800 ppm.

Furthermore, as shown, the preferred range of PEG loading may further need to be tailored to the characteristics of the polymer, and in particular the rheological characteristics of the polymer, that the PEG-based PPA composition is configured for. For example, polymers with lower MI and/or higher MIR (e.g., metallocene-catalyzed linear low density ethylene copolymers) may require higher PEG loadings, even of the higher Mw PEG species just discussed. For example, when MI is less than 0.45g/10min (190 ℃,2.18 kg) (and optionally further when MIR is greater than 30), a loading of 700ppm or higher, even up to 1000 or 1100ppm, may be required, and even various PEGs of higher Mw may be required.

Given the complexity of encountering potential diminishing returns in melt fracture elimination at higher PEG loadings for higher Mw PEG species in some polymers, while higher PEG loadings are required for other polymers (e.g., low MI species), some embodiments herein emphasize simplicity, particularly by targeting PEG with Mw in the mid-range of the above phenomenon (e.g., mw in the 7000 or 7500 to 11000g/mol range, such as 7500 to 9000g/mol or 9000 to 11000 g/mol). This enables stable tailoring of the PEG loading of the polymer while avoiding the problem of substantial loss of performance when turning to higher loadings, as sometimes observed in higher molecular weight PEG.

Similar benefits of simplicity can be achieved using lower Mw PEG species for some of the above embodiments (i.e., increasing loading tends to result in increased performance without having to strictly consider polymer rheology). Also, while the higher Mw PEG species of the other embodiments described above may introduce some additional complexity in balancing polymer rheology, they may still bring their own substantial benefits in the form of generally lower desired loadings. Thus, the present disclosure generally encompasses all such PEGs with different benefits; the skilled artisan having the benefit of this disclosure will be able to readily select the most appropriate PEG species from these for a given desired PPA.

PPA blend counterparts

There is another approach to address the differences that may be encountered when handling polymers of different rheology. As previously shown, it was found that PPA blend partners (such as fatty acid metal salts) can be useful additives to PEG in PEG-based PPA compositions, particularly when the PPA composition is configured in a polymer composition having an MIR of 20 or less (such as 17 or less), and optionally an MI of 1.0g/10min or more (such as 1.25 or more, or 1.5 or more), and additionally optionally having a broad orthogonal composition distribution (in the case of, for example, ethylene copolymers). Such blend partners may be particularly advantageous additives to PEG (and in particular PEG having a Mw in the range 7500 to 11000 g/mol). Additionally, blend partners may be included such that the weight ratio of PEG to blend partner in the PEG-based PPA composition (and thus in the polymer composition) is in the range of 30:70 to 70:30, preferably 40:60 to 60:40; such as at a 1:1 (50:50) ratio.

It is further noted that when PPA blend partners are used, the PEG loading in the PEG-based PPA composition (and thus in the polymer composition) can be advantageously reduced. For example, when 1000ppm of PEG is used in a PPA composition based on PEG in the absence of a PPA blend partner, adding 500ppm of PPA blend partner may simultaneously allow only 500ppm of PEG to be used. Thus, in some cases, the addition of PPA blend partners may be such that it replaces PEG at a 1:1 ratio (i.e., per 1ppm PPA blend partner added to a PEG-based PPA composition, the amount of PEG in the PPA composition may be reduced by 1 ppm), although it is expected that a 1:1 replacement ratio is not always required. More generally, when PPA blend partners are employed, the PEG-based PPA composition may comprise each of PEG and PPA blend partners in an amount ranging from a low point of any of 200, 250, 300, 350, 400, 450, or 500ppm to a high point of any of 1000, 1500, 2000, 2500, 5000, 7500, 10000, or 15000ppm, and further such that the weight ratio of these components (PEG and PPA blend partners) is within the previously described ranges.

As shown, preferred PPA blend partners include fatty acid metal salts. As used herein, fatty acid refers to a carboxylic acid (formula R x-COOH, wherein R is alkyl or alkenyl) wherein R is C ₈ or greater (meaning that the alkyl or alkenyl contains at least 4 carbon atoms). Preferably, R is an aliphatic carbon chain having at least 4 carbons, such as at least 6 or at least 8 carbon atoms. It may be saturated or unsaturated (and may have one or more unsaturations in the case of unsaturation). Examples include the following, unless explicitly stated otherwise to have one or more unsaturations, where the values of R are expressed as saturated carbon chains: octanoic acid (where R is C ₇), decanoic acid (R is C ₉), lauric acid (R is C ₁₁), myristic acid (R is C ₁₃), palmitic acid (R is C ₁₅), oleic acid (R is C ₁₇, with monounsaturation), stearic acid (R is C ₁₇), arachic acid (R is C ₁₉), arachidonic acid (R is C ₁₉, with multiple unsaturations), erucic acid (R is C ₂₁, with monounsaturation), behenic acid (R is C ₂₁), lignoceric acid (R is C ₂₃), and cerotic acid (R is C ₂₃).

Various metals suitable for forming salts with fatty acids are contemplated, including those of group 1 or group 2 of the periodic table (e.g., lithium, sodium, potassium, beryllium, magnesium, calcium). Metals having different valences such as aluminum and zinc are also contemplated.

Particularly interesting metal salts include metal stearates, such as zinc stearate (although stearates of any of the other metals described above are also contemplated). Zinc stearate may be of particular interest because of its already widespread use in polymer compositions, although it has not heretofore been used in fluorine-free PPA as such a major blend component, and has not been blended with surfactants and/or lower molecular weight PEG as discussed above.

Along these lines, it is also noted that US2017/0342245 (cited above) describes the use of zinc stearate (or other metal salts of various acids) as a heat stabilizer for very high molecular weight PEG compounds, i.e. as a polymer processing additive. However, as also previously noted, the disclosure focuses on the need for high molecular weight PEG in its composition; and furthermore, when used with PEG, the reported amount of zinc stearate is extremely small compared to PEG (e.g., zinc stearate: PEG ratio of 3:100), contrary to the following findings of the present invention: zinc stearate (or other metal salt of fatty acid) is preferably present at much higher levels when present in the blend (e.g., in a ratio of 30:70 to 70:30, such as 1:1, as discussed above).

Finally, the other compound may be a suitable PPA blend partner. For example, polysorbates have shown promise as fluorine-free PPA compounds, particularly when blended with PEG. More generally, these compounds belong to a class of compounds comprising sorbitan esters comprising a non-polar carboxylic acid ("lipophilic tail") attached to a polar sorbitan group (the "hydrophilic head" of such a molecule) via an ester linkage. Also of interest are polyoxyethylene derivatives of sorbitan esters comprising a plurality of polyoxyethylene oligomers chemically substituted onto the sorbitan group. The polyoxyethylene derivatives of these sorbitan esters may also be referred to as polysorbates.

More particularly, the polyoxyethylene derivative of sorbitan esters (also known as polysorbates) may take the form of the following formula (I):

Wherein: one of R ¹-R⁴ is a linear fatty acid moiety and the other three of R ¹-R⁴ are each hydrogen; and w, x, y, and z are such that 10.ltoreq.w+x+y+z.ltoreq.40; preferably 15.ltoreq.w+x+y+z.ltoreq.25; more preferably w+x+y+z=20. The linear fatty acid moiety preferably has the formula (c=o) (CH ₂)_aCH₃) wherein a is an integer between 10 and 25 (inclusive), preferably between 12 and 18 (inclusive), although the fatty acid moiety may alternatively comprise a double bond along the hydrocarbon chain (i.e. it may comprise a single unsaturation), such that the formula is (c=o) (CH ₂)_b(CH)＝(CH)(CH₂)_cCH₃) wherein b and C are each integers and b+c adds up to an integer between 8 and 23 (inclusive), preferably between 10 and 16 (inclusive).

Specific examples of polysorbates include polysorbate 20 (polyoxyethylene (20) sorbitan monolaurate); polysorbate 40 (polyoxyethylene (20) sorbitan monopalmitate); polysorbate 60 (polyoxyethylene (20) sorbitan monostearate); polysorbate 80 (polyoxyethylene (20) sorbitan monooleate). 20, 40, 60, and 80 after "polysorbate" indicate the type of fatty acid moiety (the "lipophilic tail" of the molecule) attached to the polyoxyethylene sorbitan moiety (the "hydrophilic head" of the molecule): 20 is monolaurate, 40 is monopalmitate, 60 is monostearate, and 80 is monooleate (an example of a monounsaturated fatty acid moiety). The "polysorbate number" designation assumes that 20 oxyethylene moieties are attached to the sorbate [ i.e., - (CH ₂CH₂ O) - ]. Alternative detailed names (e.g., "polyoxyethylene (20) sorbitan monostearate") indicate the number of oxyethylene moieties substituted on the sorbitan (20) and the fatty acid moiety (monostearate) appended to one of these moieties.

In certain embodiments, the surfactant may be or may comprise one or more of the following: polysorbate 20, polysorbate 40, polysorbate 60, and/or polysorbate 80. For example, the surfactant may be or may comprise polysorbate 60.

Commercially available examples include Avapol ^TM K (polysorbate 60) from Ai Wada company; tween ^TM detergent from sigma-aldrich or Tween ^TM 20Surfact-Amps detergent solution from Siemens Feier (Thermo Scientific ^TM); and Tween ^TM, a viscous liquid from sigma-aldrich company (also known in the european union as food additive number E434).

Additionally or alternatively, surfactants may be employed that are variants of the specific polysorbates just described. For example, referring again to formula I, two, three, or all of R ¹-R⁴ may each be a linear fatty acid moiety (where the remainder of R ¹-R⁴ (if any) is hydrogen). Examples of such compounds include polyoxyethylene sorbitan tristearate, wherein three of R ¹ to R ⁴ are fatty acid moieties, stearate, and another of R ¹ to R ⁴ is hydrogen.

Finally, reiterating in other embodiments, sorbitan esters may be used in the polymer composition as PPA blend partners. With reference to formula (I), w, x, y, and z will each be 0 (which means that there is no oxyethylene moiety). An example of such a compound is sorbitan tristearate, wherein x, w, y, and z are each 0; three of R ¹ to R ⁴ are fatty acid moieties, stearate, and another of R ¹ to R ⁴ is hydrogen.

PEG master batch

Relatively lower molecular weight PEG (e.g., mw 40,000g/mol or less, such as 20,000g/mol or less) may present some processing challenges due to the lower melting point; however, these challenges are easily overcome by configuring PEG as a PEG masterbatch when better handling is needed (e.g., as a solid additive delivered to the compounding extruder in a polymer finishing process). Such PEG masterbatches comprise PEG and a carrier resin. In general, PEG masterbatches can be used in place of PEG in any of the PEG-based PPA compositions described herein, such that the equivalent final loading of PEG in the PEG-based PPA composition (and thus, the PEG loading in the polymer composition) is maintained. Thus, a PEG masterbatch having a PEG loading of 4wt% can be configured in a polymer composition at a concentration of 25,000ppm (2.5 wt%) to achieve the target of a PEG loading of 1000ppm in the polymer composition. One of ordinary skill will be readily able to recognize the PEG masterbatch loadings required to achieve the desired total PEG loading in the polymer composition in accordance with the description of the preferred PEG loadings above.

Furthermore, as just shown, the PEG masterbatch comprises lower molecular weight PEG. Thus, the preferred PEG molecular weight limitations as previously discussed are equally applicable to embodiments in which a PEG masterbatch is employed (e.g., such that all PEG in the PEG masterbatch, and thus all PEG in the polymer composition, have a Mw of less than 40,000g/mol; e.g., less than 35,000g/mol, or less than 33,000g/mol, or less than 22,500g/mol, or less than 20,000g/mol, or less than 12,000g/mol, such as less than 10,000 g/mol). Also, the PEG molecular weight may preferably be in the range of 7500 to 11000g/mol, as discussed just in connection with the simplified PEG configuration strategy.

The carrier resin may be any suitable olefin homo-or copolymer, but preferred carrier resins are generally compatible with the target polymer in a given production campaign. That is, for production activities of ethylene-based polymers, ethylene-based carrier resins (e.g., having at least 50wt% units derived from ethylene) are preferred; while for propylene-based copolymer production activities such as propylene-ethylene elastomers, propylene-ethylene copolymer carrier resins or other propylene-based carrier resins (having at least 50wt% of units derived from propylene) would be preferred. In addition, the carrier resin preferably is relatively easy to process, i.e., has a Melt Index (MI) of 0.8g/10min or greater, such as 1.0g/10min or greater, or 1.5g/10min or greater. Specific examples include polyethylene having such MI. Ethylene copolymers are suitable examples of such polyethylenes, such as metallocene-catalyzed copolymers of ethylene with one or more of 1-butene, 1-hexene and 1-octene, known as mLLDPE (metallocene linear low density polyethylene), for example, an extruded ^TM performance polyethylene from ExxonMobil (ExxonMobil), such as extruded 1018 or extruded 2018. Other examples include ziegler-natta catalyzed LLDPE (ZN-LLDPE), such as copolymers of ethylene with 1-butene, 1-hexene and/or 1-octene catalyzed by ziegler-natta catalysts (such polymers typically have a broader molecular weight distribution, mw/Mn, than metallocene catalyzed counterparts). Yet another suitable example includes Low Density Polyethylene (LDPE), which may be produced by a free radical polymerization, particularly a high pressure polymerization process.

The amount of PEG loading in the masterbatch can be adjusted as desired, and one of ordinary skill will readily recognize that there is an inverse relationship between the amount of PEG loading in the PEG masterbatch and the amount of masterbatch to be configured in the polymer composition in order to achieve the target amount of PEG loading in the polymer composition (e.g., when the PEG masterbatch contains more PEG, less PEG masterbatch is correspondingly required to be loaded into the polymer composition). To illustrate, example loadings of PEG in the PEG masterbatch include PEG in the range of low points of 1, 2,3,4, or 5wt% to high points of 5,6,7, 8, 9, 10, 20, 25, 30, 35, 40, 45, or 50wt%, with the proviso that the high end is greater than the low end of any of the foregoing ranges from low end to high end of any of the foregoing being contemplated. However, it is preferred to keep the PEG loading in the masterbatch relatively low (e.g., in the range of 1-20wt%, such as 1-10wt%, or 2 to 7 wt%), especially for PEG having a Mw in the range of 7500 to 11,000 g/mol. Thus, a PEG masterbatch comprising 4wt% PEG (based on the mass of the masterbatch) can be configured at a 2.5wt% loading (25000 ppm) based on the mass of the polymer composition to maintain a PEG loading of 1000ppm of the polymer composition; and is configured at a loading of 5.0wt% based on the mass of the polymer composition (50000 ppm) to maintain a PEG loading of 2000ppm in the polymer composition.

Finally, as discussed elsewhere herein, additional additives and/or PPA blend partners may be included in the polymer composition. It is contemplated that such additives and/or PPA blend partners may be added to the polymer composition separately from the PEG masterbatch or as part of the PEG masterbatch.

However, in yet other embodiments, the PEG alone may be an excellent PPA, and thus the PEG masterbatch of such embodiments may not have a PPA blend partner, and the final polymer product may be free or substantially free of fatty acid metal salts and/or polysorbates, or other PPA blend partners. In this context, "substantially free" means that no such compound is intentionally added, but that small amounts of impurities (e.g., 10ppm or less, preferably 1ppm or less, such as 1ppb or less) may be present.

Method of incorporating PEG-based PPA compositions into polymer compositions

The method according to various embodiments includes adding polyethylene glycol (or equivalently, a PEG masterbatch) and/or a PEG-based PPA composition (according to the description above) to the polymer composition (e.g., polymer particles and/or syrup) exiting the polymerization reactor to form a pre-product polymer mixture in or upstream of the compounding extruder. Thus, the pre-formed polymer mixture comprises the polymer and the PEG-based PPA composition (both according to the respective description above), and any optional other additives (which may be provided to the mixture with, before or after the PEG-based PPA composition). The preform polymer mixture may be, for example, a polymer melt (e.g., formed in or just upstream of a compounding extruder). The mixture is then extruded and optionally pelletized to form an additional polymer composition (e.g., polymer pellets) comprising the PEG-based PPA composition and the polymer (each as per above, and wherein the PEG or the PEG-based PPA composition is in an amount as discussed above) and one or more optional other additives.

Additionally or alternatively, the method can include mixing the finished polymer (e.g., polymer pellets) with PEG or a PEG-based PPA composition to form a polymer article mixture; and processing the polymer article mixture to form a film. Such processing may be according to methods well known in the art, and in particular according to blown film extrusion.

Thus, more generally, the methods of the present disclosure may include: the PEG (or PEG masterbatch) is blended with the polymer composition to form a polymer mixture, and the polymer mixture is formed into a polymer product. Blending may be performed as part of a finishing process (e.g., where the polymer composition is a reactor grade polymer, such as pellets; and the polymer product comprises polymer pellets, providing a ready-to-use polymer product for use in preparing a film or other polymer article). Or blending may be performed as part of a process for forming a polymeric article, such as a film, for example, wherein the polymeric composition is a finished polymeric composition, such as a polymeric pellet; and the polymer product comprises a polymer article, such as a film. Such processes highlight more flexible methods in which PPA-free polymer pellets or other finished polymer products are prepared for blown film or other article production by adding a PEG-based PPA composition (e.g., PEG or PEG masterbatch). This also highlights embodiments of the present disclosure that include PEG masterbatches that can be prepared as flexible products for addition to any number of finished polymer products depending on the needs of the article (e.g., film) production.

The above methods, as well as any other method of mixing PEG (or PEG-based PPA) with a polymer to form a polymer composition as described herein, also include thoroughly mixing PEG into the polymer. The inventors have unexpectedly found that not all methods of mixing PEG can be well mixed; instead, the PEG (or PEG-based PPA composition) should be melt blended with the polymer at a sufficiently high temperature and/or specific energy input (total mechanical energy per unit weight forced into the polymer, e.g., J/g, a measure of the degree of mixing) to achieve adequate homogenization in the PEG and polymer. For example, melt blending PEG and polymer (e.g., in a compounding extruder) at high temperatures (e.g., 150 ℃ or higher, such as 200 ℃ or higher) can achieve adequate homogenization, such as by melting and then coextrusion, while simply melting PEG and tumble blending with polymer does not achieve adequate homogenization. Thus, the methods of the various embodiments include mixing the two components in a manner that ensures that the PEG and polymer (e.g., polyethylene) melt during mixing (e.g., melt mixing, coextrusion in a compounding extruder). A preferred method according to some embodiments includes melt blending and co-extruding the PEG and polymer (and optionally other additives) in a compounding extruder and granulating the mixture as it exits the extruder, thereby locking the homogeneously blended mixture in place. More precisely, such a method may comprise: (a) Feeding a PEG composition and a polymer (e.g., polyethylene) into an extruder (optionally with other additives); (b) Co-extruding the PEG composition and the polymer in an extruder at an elevated temperature (e.g., 200 ℃ or higher) suitable for melting both the PEG and the polymer; and (c) granulating the extrudate to form a polymer composition comprising the PEG-based PPA. Preferably, extrusion is performed under an oxygen-deficient atmosphere (e.g., nitrogen atmosphere).

In the discussion above, as with the other discussion herein, when referring to "PEG," PEG masterbatch may be substituted as long as the relative amount of PEG delivered to the polymer composition by masterbatch remains consistent with the amount of PEG alone delivered to the polymer composition.

Other additives

As noted, other additives optionally may also be present in the polymer composition (e.g., antioxidants, stabilizers such as UV stabilizers, catalyst neutralizers, and other additives known in the polymerization arts). Where such additives are used, they are also preferably free or substantially free of fluorine. Further, reiterating that in the presence of other additives, the mass of such additives is included in the denominator used to determine the ppm loading of PEG-based PPA described herein (i.e., ppm loading is based on the total mass of polymer + PPA + other additives).

According to various embodiments, it may be advantageous to employ an additive package that includes an anti-caking agent and/or a slip agent, possibly along with other additives. In particular, with respect to antiblocking and slip agents, the data indicate that they can provide the potential advantage of faster elimination of the melt portion when used with PEG-based PPA. Examples of anti-caking agents are well known in the art and include talc, crystalline and amorphous silica, nepheline syenite, diatomaceous earth, clays, or various other anti-caking minerals. Specific examples include Optibloc agents available from mineral technology company (Mineral Technologies). Examples of slip agents for polyolefins include amides such as erucamide and other primary fatty amides such as oleamide; and further includes certain types of secondary (bis) fatty amides. The anti-caking agent loading is typically about 500 to 6000ppm, such as 1000 to 5000ppm; slip agent loadings are typically 200 to 1000, 2000, or 3000ppm. Others may include, for example: a filler; antioxidants (e.g., hindered phenols such as IRGANOX ^TM additives available from baba-Geigy); phosphites (e.g., IRGAFOS ^TM compounds available from babassa); an anti-blocking (anti-blocking) additive; tackifiers such as polybutenes, terpene resins, aliphatic and aromatic hydrocarbon resins, alkali metal stearates and glycerol stearates, and hydrogenated rosins; a UV stabilizer; a heat stabilizer; a release agent; an antistatic agent; a pigment; a colorant; a dye; a wax; silicon dioxide; a filler; talc; mixtures thereof, and the like.

Film and method for producing the same

As noted, an important reason for using PPA is to eliminate melt fracture in blown films. Ideally, when replacing current PEG-based PPA compositions with PPA blends of the present disclosure, films made from polymer compositions comprising such PEG-based PPA compositions will exhibit similar or superior properties compared to films made using polymer compositions comprising conventional PPA.

Accordingly, the inventive content of the present disclosure may also be embodied as a film made from any of the above-described polymer compositions (and in particular polyethylene compositions) comprising a polymer and 250 to 15000ppm (e.g., 250 to 11000 ppm) of a PEG-based PPA composition (e.g., such that the Mw of one or more PEGs in PPA is less than 40,000g/mol, such as in the range of 3000, 4000, 5000, 6000, or 7500g/mol to 11000, 15000, 20000, or 35000 g/mol), and preferably is free or substantially free of fluorine; wherein the film has one or more (and preferably all) of the following:

1% secant Modulus (MD) within +/-5% psi, preferably within +/-1% psi, of the value (psi) of an otherwise identical film made using fluoropolymer-based PPA instead of PEG-based PPA composition;

elmendorf tear (Elmendorf tear) (MD) within +/-10% g, preferably +/-5% g of the value (g) of an otherwise identical film made using fluoropolymer-based PPA instead of PEG-based PPA composition;

Total haze within +/-25%, preferably within +/-10%, and/or less than 6% of the value (in%) of an otherwise identical film made using a fluoropolymer-based PPA instead of a PEG-based PPA composition;

Gloss (MD) within +/-12%, preferably +/-10% of the value (in GU) of an otherwise identical film made using fluoropolymer-based PPA instead of PEG-based PPA composition; and

Dart values (Dart) within +/-1%, preferably within +/-0.5%, or even within +/-0.1% of the value (g) of an otherwise identical film made using fluoropolymer-based PPA instead of PEG-based PPA composition.

When the PEG-based PPA composition comprises a PPA blend partner (e.g., a fatty acid metal salt, such as zinc stearate), the amount of the PEG-based PPA composition (in ppm) still applies, but within these amounts (e.g., within 250 to 15000 ppm), the PEG and PPA blend partner are present in a weight ratio of 30:70 to 70:30 (PEG: PPA blend partner), and preferably in a ratio of 1:1 (e.g., such that 1000ppm of such an embodiment corresponds to 500ppm PEG and 500ppm PPA blend partner).

Furthermore, in the discussion above, "made using a fluoropolymer-based PPA in place of a PEG-based PPA composition, but otherwise identical" films are intended to mean that films made using an effective amount of a PEG-based PPA composition are compared to films made using an effective amount of a fluoropolymer-based PPA; it is not necessary to use the same amount of each PPA. An effective amount is such that visible melt fracture is eliminated from the film, consistent with the discussion in connection with example 1.

Examples

In order to facilitate a better understanding of embodiments of the present invention, the following examples of preferred or representative embodiments are given.

Example 1 test run

Blown film tests were performed on a blown film extruder line L2, with extruder and die characteristics, conditions and temperature profiles as set forth in table 1 below.

TABLE 1L 2 extruder and die processing conditions

Seven different polyethylene resins were used to make a variety of films. Nominally, each sample of the same resin had density, MI and MIR values; in general, the nominal properties of each of the seven resins are shown in Table 2 below. Table 2 also indicates the composition distribution of each PE resin, where "homogeneous" means that the comonomer is relatively uniformly distributed over polymer chains of different lengths, and "BOCD" means "broad orthogonal composition distribution" means that the comonomer distribution, where longer (higher molecular weight) chains in the polymer composition have a greater amount of comonomer than shorter (lower molecular weight) chains. The "homogeneous" and "BOCD" characteristics may each be approximated by a range of Composition Distribution Breadth Indices (CDBI) defined as the weight percent of copolymer molecules having a comonomer content within 50% of the total molar median of the comonomer content (i.e., the weight percent of polymer molecules having a comonomer molar content within the range of 0.5 x median to 1.5 x median); for example, it is cited in U.S. Pat. No. 5,382,630. The CDBI of the "homogeneous" PE resin is greater than 60%; BOCD resins have a CDBI of less than 40% and furthermore allow for the presence of greater amounts of comonomer on higher molecular weight chains than on lower molecular weight chains. Various other methods that may be used to quantify BOCD properties are discussed above.

TABLE 2 nominal Properties of PE resins used in the test runs

However, due to the expected variation of the measurement conditions and the nature of the measurement characteristics, some deviation was observed in each resin in the different test formulations. Thus, table 3 below reports the specific measurements of each resin run for each test, grouped according to the PPA composition tested (where "Dynamar" is Dynamar ^TM FX5929M for the PPA composition in Table 3, existing fluoropolymer-containing PPA; "Pluriol" isE8000, PEG with Mw of about 8,000 g/mol; avapol is Avapol ^TM K from Ai Wada; and ZnSt is a zinc stearate composition (an example of a metal salt of a fatty acid).

TABLE 3 resin and PPA formulations used for each test run

Film production was performed using the same general process for each test run in order to investigate the use of different PPA on each PE resin to eliminate melt fracture; the extruder die pressure experienced by each PPA was also recorded and analyzed. More specifically, the process is as follows:

Purging the resin with: The extruder was run on a 2:1 blend of KC 30. The process was continued until clean for about 30min. The purge resin used in this preliminary cleaning step for each test was a PPA-free version of the same polyethylene used for the film production for the given test.

The inner die was manually cleaned and polished with polishing paste (modified old purpose die polish (Improved Old Purpose Mold Polish) by IMS).

The purge resin was run until KC30 disappeared and the melt fracture stabilized for about 45min. Typical purge resin rates are 2-3 lbs/hr to obtain a stable film product free of melt fracture.

Set the test timer to 0. The test resin (test resin plus PPA blend) was fed at the target output rate. Rpm was adjusted to achieve the target output during the first 15 min.

Every 15min: samples of 2 feet of film were taken and w/test resin, date and time of collection were marked and the running data recorded in the table.

Run until first arrival: melt fracture was eliminated or 105 minutes.

When each of the PPA-containing resins tested was fed, as shown in fig. 1, the melt fracture began to slowly disappear in the form of a streak. Referring to fig. 1, as PPA is added, a melt fracture-free condition begins to appear as a band 101 in the machine direction 110 of the film 100 (i.e., the direction of film extrusion and blowing). Fig. 1 is a schematic diagram conceptually illustrating this transition period with stripes 105 of melt fractured film material and stripes 101 of non-melt fractured film. Over time, these bands 101 increase in width and the melt fracture area decreases, and ideally, will eventually be completely eliminated. As shown, for these example 1 experiments, 2 feet of film samples were obtained every 15 minutes for visual inspection to determine the% melt fracture remaining in the film at a given 15 minute interval. When melt fracture is completely eliminated between one sample and the next (e.g., between 45 minutes and 60 minutes of sample), the elimination is reported at the midpoint between the samples, rounded down (e.g., recorded as 52 minutes for the given 45 minutes and 60 minutes examples).

The results of the example 1 test are summarized in tables 4-10 below (where Table 4 corresponds to the test using different PPAs with PE 1; table 5 corresponds to the test using different PPAs with PE 2; etc.). Tables 4-10 report the following information for each test run: the amounts and ratios of the components in each PPA blend; the total PPA used; melt fracture observed at 105min (MF at 105 min), expressed as% film area containing visible melt fracture; melt Fracture Elimination (MFE) time in minutes; operating pressure (psi) at the extrusion die; initial pressure (psi) at the extrusion die; die head coefficient; and a ratio output. The starting pressure and operating pressure provide additional performance tracking indicators, as to the greater the drop in pressure from starting pressure to operating pressure, the better (which indicates easier processing). In this experiment, at the end of the test (end time if melt fracture persists, otherwise time when complete elimination of melt fracture is observed) the operating pressure is considered the final pressure. The specific output is the output of the film (defined as pounds per hour divided by the extruder speed (rpm)), and the die coefficient is the output (pounds per hour) divided by the die circumference (inches).

TABLE 4 films prepared using PE1 and test PPA compositions

Fig. 2 is a graphical representation of the% melt fracture over time observed for the PE1 film of table 4, showing the rate at which each of the test PPA compositions eliminated the melt portion. FIG. 2 shows very similar performance between C-1 and I-1, indicating that Pluriol PPA is likely to eliminate melt fracture at an additional few minutes of run time.

TABLE 5 films prepared using PE2 and test PPA compositions

Fig. 3 is a graphical representation of the% melt fracture over time observed for the PE1 film of table 5, showing the rate at which each of the test PPA compositions eliminated the melt portion. Fig. 3 shows that the performance of pluriols is again similar to current DYNAMAR PPA or better than DYNAMAR PPA, and Avapol also shows excellent performance. The ZnSt/Pluriol initial elimination of melt fracture was slower, but the final elimination level was similar. As with table 4 and fig. 2, fig. 3 shows that pluriols and Avapol and possibly also ZnSt/pluriols are expected to eliminate melt fracture at additional run times.

TABLE 6 films prepared using PE3 and test PPA compositions

Fig. 4 is a graphical representation of the% melt fracture over time observed for the PE1 film of table 6, showing the rate at which each of the test PPA compositions eliminated the melt portion. Fig. 4 shows that while Pluriol PPA (I-3) exhibited more excellent performance (even compared to current DYNAMAR PPA), all of the PPA compositions tested exhibited a strong downward trend in melt fracture elimination.

TABLE 7 films prepared using PE4 and test PPA compositions

Fig. 5 is a graphical representation of the% melt fracture over time observed for the PE1 film of table 7, showing the rate at which each of the test PPA compositions eliminated the melt portion. Fig. 5 shows that both ZnSt/Pluriol and Pluriol performed better than DYNAMAR PPA in most experiments, but only ZnSt/Pluriol combinations eventually reached 0% melt fracture at the end of the run, while Pluriol and DYNAMAR PPA films still exhibited small amounts of melt fracture (again, expected to be eliminated at additional run times). Interestingly, avapol (polysorbate) PPA appeared to stabilize at about 30% melt fracture, indicating that it may not eliminate melt fracture of PE4 at 1000ppm loading; higher loadings may be required to eliminate melt fracture.

TABLE 8 films prepared using PE5 and test PPA compositions

Fig. 6 is a graphical representation of the% melt fracture over time observed for the PE1 film of table 8, showing the rate at which each of the test PPA compositions eliminated the melt portion. Fig. 6 shows that the performance of all PPA tested was highly similar (and very strong), but of interest, both Pluriol, avapol and ZnSt/Pluriol were superior to Dynamar in terms of melt fracture elimination in PE5, as summarized in table 8.

TABLE 9 films prepared using PE6 and test PPA compositions

Fig. 7 is a graphical representation of the% melt fracture over time observed for the PE1 film of table 9, showing the rate at which each of the test PPA compositions eliminated the melt portion. Similar to fig. 6, fig. 7 shows the powerful performance of all PPA tested, and three alternative fluorine-free PPA formulations again provided faster melt portion elimination than the current fluoropolymer-based DYNAMAR PPA.

TABLE 10 films prepared using PE7 and test PPA compositions

Fig. 8 is a graphical representation of the% melt fracture over time observed for the PE1 film of table 10, showing the rate at which each of the test PPA compositions eliminated the melt portion. Fig. 8 shows that all fluorine-free PPA formulations outperform Dynamar formulations in rapidly eliminating almost all melt fracture except that there is still a small amount of melt fracture in Avapol PPA films (but the trend shows that melt fracture may be eliminated at additional run times).

Discussion of the invention

Except for two experimental runs using Avapol (polysorbate) as PPA, all fluorine-free alternative PPA formulations perform comparable to or better than current fluoropolymer DYNAMAR PPA formulations. Also, both cases of some degree of melt fracture (I-8 and I-11) may be overcome by greater loadings when Avapol remains. In addition, fluoropolymer-free PPA formulations typically exhibit faster melt fracture elimination than current DYNAMAR PPA, with similar or only slightly higher pressure increases, indicating that all three types of fluoropolymer-free PPA formulations tested hold good promise.

However, reviewing the entire data set, it is seen that PPA compositions using just Pluriol (PEG 8 k) and PPA compositions using 50/50 blends of Pluriol and ZnSt are the most stable, because of the highest success rate of these PPA compositions among a range of different PE resins, and generally superior performance in terms of rate of melt fracture elimination to current DYNAMAR PPA. In particular, pluriol alone did not completely eliminate melt fracture during the 105 minute test period in only three cases (I-1, I-2 and I-4), but in all three cases only a very small portion of the films exhibited melt fracture (0.2%, 0.2% and 0.5%, respectively), indicating that slightly longer run times are likely to result in complete elimination of melt fracture.

Also, the Pluriol and ZnSt combinations failed to completely eliminate melt fracture in only three cases (I-15, I-16 and I-17); in each case, only a small amount of melt fracture (3.4%, 1.2% and 0.9%, respectively) remained.

Summarizing this information, individual pluriols perform better when applied stably for multiple resins with different rheology and composition profiles; furthermore, the results indicate that ZnSt can be selectively used as PPA blend partner in targeted situations at PEG 8k to even further improve the stability of PPA compositions during polymer production activities. In particular, table 7 (involving PE 4) is the only example in which (i) pluriols alone (PEG 8K) failed to eliminate melt fracture within 105 minutes, while (ii) pluriols/ZnSt combinations were successfully eliminated. This indicates that ZnSt can be used when referring to polymers having one or more of the following: MIR is relatively lower; MI is relatively higher; and/or BOCD properties. Indeed, from the observation of table 6 (PE 3), this alternative configuration may be particularly useful, where pluriols alone were successful, while the addition of ZnSt resulted in melt fracture on the film at 105 minutes. PE3, like PE4, has a MI of 1.0, but especially clearly has a higher MIR (30 compared to 20MIR for PE 4), which further indicates that the ZnSt blend partner is only suitable for films made from lower MIR resins.

It is also seen that, in general, BOCD resins (PE 1, PE2, PE3, and PE 4) present a greater challenge for melt fracture elimination, while the homogeneous materials tested (PE 5, PE6, PE 7) have a wider range of choices, noting that all PPA choices perform very well (only one example, where polysorbate fraction Avapol left 0.4% of melt fracture after 105 minutes, as indicated by the trend over time, and that complete elimination may require slightly longer run times to achieve). Thus, the above guidance regarding the use of ZnSt as a PPA blend partner may only be necessary when referring to films prepared from BOCD-type polymers.

Finally, although the best performing PPA in a single run varies from resin to resin, in practice, using disparate PPA compositions at different levels is very inefficient in polymer production campaigns; thus, it would be of great value to determine the most stable PPA composition or compositions of the plurality of grades. Thus, selective targeted addition of pluriols of ZnSt provides an excellent solution.

Example 2 masterbatch

In view of the prospect of PEG (optionally with ZnSt) as PPA, further experiments were performed using PEG masterbatches to determine its suitability and effectiveness. The use of the masterbatch approach makes even the relatively lower molecular weight PEG compounds (e.g., PEG 8K) investigated herein easier to handle, overcoming the thermal instability problem (e.g., lower melting point) that is known to lead to lower molecular weight PEG handling problems.

Thus, a masterbatch was prepared comprising 4wt% in an advanced ^TM 2018 polyethylene carrier resinE8000 (said wt% being based on the total mass of the carrier resin). The extruded ^TM 2018 polyethylene was a metallocene-catalyzed ethylene-1-hexene copolymer with an MI of 2.0g/10min (190 ℃,2.16kg load) and a density of 0.918g/cm ³. A total of 5wt% PEG masterbatch was compounded with 95wt% of an ex ^TM 1018 ethylene-1-hexene copolymer containing no PPA (available from exxon mobil chemical company (ExxonMobil Chemical)) and extruded into a film in the same manner as the test run film produced in example 1. This means that the total loading of PEG was 2000ppm (based on the mass of the polymer composition comprising PEG masterbatch and extruded ^TM 1018 PE). The formulation successfully eliminated melt fracture of the film after 82 minutes.

Test method

Table 11 below reports the test methods used in connection with the examples. Unless otherwise indicated in the description of a given characteristic, these methods will also be used to determine the characteristic according to embodiments described herein.

Table 11. Measurement method.

For brevity, only certain ranges are explicitly disclosed herein. However, any lower limit may be combined with any upper limit to list a range not explicitly recited, and any lower limit may be combined with any other lower limit to list a range not explicitly recited, as well as any upper limit may be combined with any other upper limit to list a range not explicitly recited in this manner. In addition, each point or individual value between its endpoints is included within the range even though not explicitly recited. Thus, each point or individual value may be combined with any other point or individual value or any other lower or upper limit as its own lower or upper limit to enumerate ranges not explicitly recited.

All documents described herein are incorporated by reference herein, including any priority documents and/or test procedures not inconsistent with such documents. As is apparent from the foregoing general description and the specific embodiments, while forms of the disclosure have been illustrated and described, various modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, the disclosure is not intended to be so limited. Also, the term "comprising" is considered synonymous with the term "including" in the united states law. Likewise, whenever a composition, element, or group of elements is preceded by the transitional phrase "comprising," it is understood that we also contemplate the same composition or group of elements having the transitional phrase "consisting essentially of … …," "consisting of … …," "selected from the group consisting of … …," or "yes" before the recited composition, element, or elements, and vice versa.

Unless otherwise indicated, the phrases "consisting essentially of … … (consists essentially of)" and "consisting essentially of … … (consisting essentially of)" do not exclude the presence of other steps, elements, or materials, whether or not specifically mentioned in the present specification, so long as such steps, elements, or materials do not affect the basic and novel features of the present disclosure, and further, they do not exclude impurities and differences normally associated with the elements and materials used.

While the present disclosure has been described with respect to various embodiments and examples, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope and spirit of the present disclosure.

Claims

1. A polymer composition comprising:

A C ₂-C₆ olefin homopolymer or a copolymer of two or more C ₂-C₂₀ alpha-olefins;

250 to 5000ppm (based on the mass of the polymer composition) of one or more polyethylene glycols, wherein all polyethylene glycols of the polymer composition have a weight average molecular weight (Mw) of less than 40,000 g/mol; and

250 To 5000ppm (based on the mass of the polymer composition) of one or more fatty acid metal salts;

wherein the weight ratio of polyethylene glycol to fatty acid salt in the polymer composition is in the range of 30:70 to 70:30;

Further wherein the homopolymer or copolymer has a melt index ratio (ratio of high load melt index at 190 ℃ C., 21.6kg load to melt index at 190 ℃ C., 2.16kg load) of 20 or less; optionally also having a melt index (MI, 190 ℃ C. And 2.16kg load) of 1.0g/10min or more; and

Further wherein the polymer composition is free of fluorine.

2. The polymer composition of claim 1 having 300 to 600ppm of the one or more polyethylene glycols and 300 to 600ppm of the fatty acid metal salt.

3. The polymer composition of claim 1 or claim 2, wherein the weight ratio of polyethylene glycol to fatty acid salt in the polymer composition is in the range of 40:60 to 60:40.

4. The polymer composition of any of the preceding claims, wherein all polyethylene glycols of the polymer composition have a Mw of less than 15,000g/mol.

5. The polymer composition of any of the preceding claims, wherein the one or more fatty acid salts comprise zinc stearate.

6. The polymer composition of any of the preceding claims, wherein each polyethylene glycol of the polymer composition has a Mw in the range of 7,500 to 11,000 g/mol.

7. The polymer composition of any of the preceding claims, wherein the homopolymer or copolymer is an ethylene copolymer comprising units derived from ethylene and units derived from one or more C ₃ to C ₂₀ a-olefins.

8. The polymer composition of claim 7, wherein the ethylene copolymer is a metallocene-catalyzed linear low density polyethylene (mLLDPE) comprising units derived from ethylene and units derived from 1-butene, 1-hexene, or 1-octene, having a density in the range of 0.905 to 0.945g/cm ³, and having a broad orthogonal composition distribution.

9. The polymer composition of claim 7, wherein the ethylene copolymer is a ziegler-natta catalyzed linear low density polyethylene (ZN-LLDPE) comprising units derived from ethylene and units derived from 1-butene, 1-hexene or 1-octene, and having a density in the range of 0.905 to 0.945g/cm ³.

10. A process for producing two or more polymer products, the process comprising:

(a) Producing a first polymer having a Melt Index Ratio (MIR) of greater than 20 and optionally also having a Melt Index (MI) of 1.0g/10min (190 ℃,2.16kg load) or less at a first time;

(b) Combining the first polymer with a first PEG-based PPA composition comprising one or more PEG and having substantially no fatty acid metal salt to form a first polymer product that is free of fluorine;

(c) Producing a second polymer having a MIR of 20 or less at a second time different from the first time, wherein the second polymer optionally further has a MI of greater than or equal to 1.0g/10min (190 ℃,2.16kg load), and further wherein the second polymer is further optionally a copolymer of ethylene and one or more C ₃ to C ₂₀ α -olefins having a broad orthogonal composition distribution; and

(D) Combining the second polymer with a second PEG-based PPA composition comprising one or more PEG and one or more fatty acid salts to form a fluorine-free second polymer product.

11. The method of claim 10, wherein the (b) combining comprises co-extruding the first PEG-based PPA composition and the first polymer; and the (d) combining comprises co-extruding the second PEG-based PPA composition and the second polymer.

12. The method of claim 10 or claim 11, wherein the first polymer product comprises 250 to 2,000ppm polyethylene glycol; and further wherein the second polymer product comprises (i) 250 to 750ppm polyethylene glycol and (ii) 250 to 750ppm of the fatty acid metal salt, wherein the (i) polyethylene glycol and the (ii) fatty acid metal salt are present in the second polymer in a weight ratio (polyethylene glycol to metal salt) in the range of 30:70 to 70:30.

13. The method of any one of claims 10 to 12, wherein the PEG-based PPA composition comprises a masterbatch comprising 2 to 8wt% PEG (based on the mass of the masterbatch) and a carrier resin selected from the group consisting of ziegler-natta catalyzed polyethylene, metallocene-catalyzed polyethylene, and free-radically polymerized Low Density Polyethylene (LDPE).

14. A continuous process for producing two or more polymer products, the process comprising:

(a) Continuously feeding a base PEG-based PPA composition comprising one or more PEG and being substantially free of fatty acid metal salts to a compounding extruder, further wherein no fluorochemical is present in the base PEG-based PPA composition;

(b) Continuously co-feeding a first polymer to the compounding extruder during a first period of time during the (a) continuous feeding, the first polymer having a Melt Index Ratio (MIR) of greater than 20, and optionally also having a Melt Index (MI) of 1.0g/10min (190 ℃,2.16kg load) or less,

(C) During the first period of time, obtaining a first polymer product comprising at least a portion of the first polymer and at least a portion of the PEG-based PPA composition, and further wherein the first polymer product is free of fluorine;

(d) Continuously adding one or more fatty acid metal salts to the base PEG-based PPA composition fed to the compounding extruder during the (a) continuous feeding and for a second period of time after the first period of time while continuously co-feeding a second polymer into the compounding extruder, the second polymer having a MIR of 20 or less, wherein the second polymer optionally further has an MI of greater than or equal to 1.0g/10min (190 ℃,2.16kg load), and further wherein the second polymer is further optionally a copolymer of ethylene and one or more C ₃ to C ₂₀ a-olefins having a broad orthogonal composition distribution;

(e) During the second period of time, a second polymer product is obtained comprising at least a portion of the second polymer, at least a portion of the PEG-based PPA composition, and at least a portion of the one or more fatty acid metal salts, and further wherein the second polymer product is free of fluorine.

15. The method of claim 14, wherein the first polymer product comprises 250 to 2,000ppm polyethylene glycol; and further wherein the second polymer product comprises (i) 250 to 750ppm polyethylene glycol and (ii) 250 to 750ppm of the fatty acid metal salt.

16. The method of claim 14 or claim 15, wherein all polyethylene glycols of each of the first and second polymer products have a weight average molecular weight (Mw) of less than 40,000 g/mol.

17. The method of claim 16, wherein the PEG-based PPA composition is a PEG masterbatch comprising 2 to 8wt% PEG (based on the mass of the masterbatch) and a carrier resin selected from the group consisting of ziegler-natta catalyzed polyethylene, metallocene catalyzed polyethylene, and free-radical polymerized Low Density Polyethylene (LDPE).

18. The method of any one of claims 14-17, wherein the fatty acid metal salt comprises zinc stearate.

19. The method of any one of claims 14-18, further comprising:

(f) Stopping said (d) continuously adding said one or more fatty acid metal salts after said second period of time and at the beginning of a third period of time during said (a) continuously feeding;

(g) Continuously co-feeding a third polymer to the compounding extruder over the third period of time, the third polymer having a Melt Index Ratio (MIR) of greater than 20, and optionally also having a Melt Index (MI) of 1.0g/10min (190 ℃,2.16kg load) or less; and

(H) During the third time period, a third polymer product is obtained comprising at least a portion of the third polymer, at least a portion of the PEG-based PPA composition, and further wherein the third polymer product is free of fluorochemical.

20. The method of any of claims 14-19, wherein the second polymer is a copolymer of ethylene and one or more C ₂-C₂₀ a-olefins and has a broad orthogonal composition distribution.