Ionomers of ethylene acid copolymers with improved melt flow and enhanced creep resistance

Abstract

An ionomer includes an ethylene acid copolymer including the polymerized reaction product of from 50 wt.% to 90 wt.% ethylene, from 0 wt.% to 40 wt.% alkyl acrylate, and from 10 wt.% to 20 wt.% monocarboxylic acid monomers, wherein from 30 mol.% to 80 mol.% of acid units are neutralized by metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150, or a mixture of aluminum cations and magnesium cations, wherein the mixture comprises a majority of magnesium cations, and wherein the ionomer has a melt flow from 2.0 to 20.0 g / 10 minutes as determined according to ASTM D1238 (at 190 °C, 2.16 kg).

Description

85548-WO-PCT / DOW 85548 WO IONOMERS OF ETHYLENE ACID COPOLYMERS WITH IMPROVED MELT FLOW AND ENHANCED CREEP RESISTANCE CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 579,835 filed August 31, 2023, the contents of which are incorporated in their entirety herein. TECHNICAL FIELD

[0002] The present disclosure generally relates to ionomers of ethylene acid copolymers, and specifically relates to ionomers of ethylene acid copolymers that provide improved melt flow and creep resistance. BACKGROUND

[0003] Ionomers are commonly used materials in various applications, because they have higher tensile strength, greater clarity, better abrasion resistance and higher stiffness than the precursor acid copolymers. For example, the ionomers of ethylene acid copolymers have found utility in many applications, such as food packaging, foamed parts, injection molded parts (e.g., cosmetic containers), and golf ball components. SUMMARY

[0004] Although ionomers may be utilized in many applications, many ionomers, including ionomers with higher acid content, lose their dimensional stability at high temperatures. This loss of dimensional stability leads to creep elongation in articles comprising the ionomers. However, ionomers with higher acid contents have many desirable properties, including high clarity, chemical resistance, toughness, and scratch resistance. Conventional approaches to improving the dimensional stability of ionomers with high acid content include at least partially neutralizing the acid groups solely using aluminum ions. Unfortunately, this approach decreases melt flow, thus85548-WO-PCT / DOW 85548 WO making the resulting ionomer difficult to melt process. Therefore, ionomers with high acid content that maintain both dimensional stability and melt flow are needed.

[0005] Embodiments of the present disclosure address this need for improved dimensional stability by utilizing neutralization formulations comprising metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150, or a mixture of aluminum cations and magnesium cations, wherein the mixture comprises a majority of magnesium cations

[0006] According to one ionomer embodiment, the ionomer may include an ethylene acid copolymer, the ethylene acid copolymer including the polymerized reaction product of from 50 wt.% to 90 wt.% ethylene, from 0 wt.% to 40 wt.% alkyl acrylate, and from 10 wt.% to 20 wt.% monocarboxylic acid monomers, wherein from 30 mol.% to 80 mol.% of acid units are neutralized by: metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150; or a mixture of aluminum cations and magnesium cations, wherein the mixture comprises a majority of magnesium cations; and wherein the ionomer has a melt flow from 2.0 to 20.0 g / 10 minutes as determined according to ASTM D1238 (at 190 °C, 2.16 kg).

[0007] These and other features, aspects, and advantages will become better understood with reference to the following description and the appended claims.

[0008] Additional features and advantages of the examples described herein will be set forth in the detailed description that follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the examples described herein, including the detailed description that follows, the claims, as well as the appended drawings.

[0009] It is to be understood that both the foregoing general description and the following detailed description describe various examples and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.85548-WO-PCT / DOW 85548 WO BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 illustrates a graphical representation of the data presented in Table 1. DETAILED DESCRIPTION

[0011] Specific embodiments of the present application will now be described. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the subject matter to those skilled in the art.

[0012] The term “polymer” refers to a polymeric compound prepared by polymerizing monomers, whether of a same or a different type. The generic term polymer thus embraces the term “homopolymer,” which usually refers to a polymer prepared from only one type of monomer as well as “copolymer,” which refers to a polymer prepared from two or more different monomers. The term “interpolymer,” as used herein, refers to a polymer prepared by the polymerization of at least two different types of monomers. The generic term interpolymer thus includes a copolymer or polymer prepared from more than two different types of monomers, such as terpolymers.

[0013] “Polyethylene” or “ethylene-based polymer” shall mean polymers comprising greater than 50% by weight of units derived from ethylene monomer. This includes ethylene-based homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of ethylene-based polymers known in the art include, but are not limited to, Low Density Polyethylene (LDPE); Linear Low Density Polyethylene (LLDPE); Ultra Low Density Polyethylene (ULDPE); Very Low Density Polyethylene (VLDPE); single-site catalyzed Linear Low Density Polyethylene, including both linear and substantially linear low density resins (m- LLDPE); Medium Density Polyethylene (MDPE); and High Density Polyethylene (HDPE).

[0014] Reference will now be made in detail to examples of ionomers including an ethylene acid copolymer, the ethylene acid copolymer including the polymerized reaction product of from 50 wt.% to 90 wt.% ethylene, from 0 wt.% to 40 wt.% alkyl acrylate, and from 10 wt.% to 20 wt.% monocarboxylic acid monomers, wherein from 30 mol.% to 80 mol.% of acid units are neutralized by: metal cations with ionic radii greater than 100 pm and ionic radii multiplied by85548-WO-PCT / DOW 85548 WO ionic charge of greater than 150; or a mixture of aluminum cations and magnesium cations, wherein the mixture comprises a majority of magnesium cations; and wherein the ionomer has a melt flow from 2.0 to 20.0 g / 10 minutes as determined according to ASTM D1238 (at 190 °C, 2.16 kg).

[0015] The ethylene acid copolymer includes or is derived from 50 weight percent (wt.%) to 90 wt.% ethylene monomer. In some examples, the polymerized reaction product includes from 50 wt.% to 90 wt.% ethylene, from 50 wt.% to 85 wt.% ethylene, from 50 wt.% to 80 wt.% ethylene, 60 wt.% to 90 wt.% ethylene, from 60 wt.% to 85 wt.% ethylene, from 60 wt.% to 80 wt.% ethylene, 70 wt.% to 90 wt.% ethylene, from 70 wt.% to 85 wt.% ethylene, or from 70 wt.% to 80 wt.% ethylene.

[0016] The ethylene acid copolymer includes at least 10 wt.% monocarboxylic acid monomers. The monocarboxylic acid can be, for example, acrylic acid, methacrylic acid, or combinations thereof. In some examples, the polymerized reaction product includes from 10 wt.% to 20 wt.% monocarboxylic acid monomers, from 10 wt.% to 18 wt.% monocarboxylic acid monomers, from 10 wt.% to 16 wt.% monocarboxylic acid monomers, from 12 wt.% to 20 wt.% monocarboxylic acid monomers, from 12 wt.% to 18 wt.% monocarboxylic acid monomers, from 12 wt.% to 16 wt.% monocarboxylic acid monomers, from 14 wt.% to 20 wt.% monocarboxylic acid monomers, from 14 wt.% to 18 wt.% monocarboxylic acid monomers, or from 14 wt.% to 16 wt.% monocarboxylic acid monomers.

[0017] Without being limited by theory, having at least 10 wt.% monocarboxylic acid monomers ensures that the resulting ionomer has desirable properties, including high clarity, chemical resistance, toughness, and scratch resistance At levels below 10 wt.% monocarboxylic acid monomers, the ionomer produced will not possess high clarity, chemical resistance, toughness, and scratch resistance.

[0018] The polymerized reaction product includes from 0 wt.% to 40 wt.% alkyl acrylate. Suitable examples of alkyl acrylates include, but are not limited to, ethyl acrylate, methyl acrylate, n-butyl acrylate, iso-butyl acrylate, or combinations thereof. In various embodiments, the alkyl acrylate has an alkyl group with from 1 to 8 carbons. In particular embodiments, the alkyl acrylate is n-butyl acrylate. In some examples, the polymerized reaction product includes from 0 wt.% to85548-WO-PCT / DOW 85548 WO 40 wt.% alkyl acrylate, from 0 wt.% to 30 wt.% alkyl acrylate, from 0 wt.% to 20 wt.% alkyl acrylate, from 0 wt.% to 10 wt.% alkyl acrylate, from 10 wt.% to 40 wt.% alkyl acrylate, from 10 wt.% to 30 wt.% alkyl acrylate, from 10 wt.% to 20 wt.% alkyl acrylate, 20 wt.% to 30 wt.% alkyl acrylate, from 20 wt.% to 40 wt.% alkyl acrylate, or from 20 wt.% to 30 wt.% alkyl acrylate.

[0019] The ethylene acid copolymer can be prepared by standard free-radical copolymerization methods, using high pressure, operating in a continuous manner. Monomers are fed into the reaction mixture in a proportion which relates to the monomer’s activity, and the amount desired to be incorporated. In this way, uniform, near-random distribution of monomer units along the chain is achieved. Unreacted monomers may be recycled. Additional information on the preparation of ethylene acid copolymers including the softening monomer can be found in U.S. Patent No. 3,264,272 and U.S. Patent No. 4,766,174, each of which is hereby incorporated by reference in its entirety.

[0020] As noted above, the ethylene acid copolymer is at least partially neutralized by one or more metal cations (to form an ionomer). From 30 mole percent (mol.%) to 80 mol.% of acid units in the ethylene acid copolymer are neutralized. In some examples, from 30 mol.% to 80 mol.%, from 32 mol.% to 80 mol.%, from 34 mol.% to 80 mol.%, from 30 mol.% to 70 mol.%, from 32 mol.% to 70 mol.%, from 34 mol.% to 70 mol.%, from 30 mol.% to 60 mol.%, from 32 mol.% to 60 mol.%, or from 34 mol.% to 60 mol.% of acid units in the ethylene acid copolymer are neutralized. Without being bound by theory, if less than 30 mol.% of acid units in the ethylene acid copolymer are neutralized, the resulting ionomer will not have the desired beneficial ionomer properties such as high clarity.

[0021] The acid units of the ethylene acid copolymer are neutralized by either metal cations with ionic radii greater than 100 picometers (pm), or a mixture of aluminum cations and magnesium cations, wherein the mixture comprises a majority of magnesium cations.

[0022] In examples where the monocarboxylic acid monomers in the polymerized reaction product are neutralized by metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150, the metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150 are selected from the group consisting of cesium, lanthanum, rubidium, strontium, and barium. In examples where the85548-WO-PCT / DOW 85548 WO monocarboxylic acid monomers in the polymerized reaction product are neutralized by metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150, the metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150 are Cesium (Cs) or Lanthanum (La).

[0023] Ionic radii for may be found in A.F. Wells, "Structural Inorganic Chemistry," 5th ed., Clarendon Press, Oxford, 1984, p. 1288 (metallic radii for 12-coordination); Huheey, pp. 292 (covalent radii for nonmetals); R.D. Shannon, Acta Crystallogr., Sect. A: Found. Crystallogr., 32, 751 (1976) (ionic radii for 6-coordination).

[0024] In examples where the monocarboxylic acid monomers in the polymerized reaction product are neutralized by metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150, the metal cations may have a coordination number of from 3 to 12, such as 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12.

[0025] Without being bound by theory, the size of the ionic radii of the metal cation and the value of the ionic radii multiplied by ionic charge correlates improved melt flow and enhanced creep resistance of resulting ionomers. Furthermore, without being bound by theory, metal cations with larger ionic radii and coordination numbers of from 3 to 12 are believed to cause improved melt flow and enhanced creep resistance of resulting ionomers, because metal cations with coordination numbers of from 3 to 12 allow for interactions with more carboxyl functionality, which provide more physical crosslinks for enhanced creep. Additionally, the lower charge density of the metal cations with the larger ionic radii are believed to enable increased polymer chain mobility (i.e. melt flow) at temperatures where the polymer is molten.

[0026] In examples where the monocarboxylic acid monomers in the polymerized reaction product are neutralized by a mixture of aluminum cations and magnesium cations, wherein the mixture comprises a majority of magnesium cations, it has surprisingly been found that the resulting ionomers have improved melt flow and when made into articles, have enhanced creep resistance. Compared to ionomers neutralized with just aluminum cations, just magnesium cations, or a mixture of aluminum cations and magnesium cations, wherein the mixture comprises a majority of aluminum cations, ionomers of the present disclosure had both melt flow within the desired parameters and creep elongation within the desired parameters, specifically, a melt flow85548-WO-PCT / DOW 85548 WO of 2.0 to 20.0 g / 10 minutes, and a percent elongation of less than or equal to 40.0% under a stress of 14 psi at a temperature of 70 °C over a period of 24 hours.

[0027] The ionomer has a melt flow from 2.0 to 20.0 g / 10 minutes as measured according to ASTM D1238 procedure A (190 °C , 2.16 kg). Unless otherwise stated, melt flow was measured in grams per 10 minutes (g / 10 minutes). In some examples, the ionomer has a melt flow from 2.0 to 20.0 g / 10 minutes, from 2.0 to 12.0 g / 10 minutes, from 2.0 to 10.0 g / 10 minutes, from 2.5 to 20.0 g / 10 minutes, from 2.5 to 12.0 g / 10 minutes, or from 2.5 to 10.0 g / 10 minutes.

[0028] If the ionomer has a melt flow below 2.0 g / 10 minutes, the ionomer may not have sufficient melt flow for processability. Conversely, if the ionomer has a melt flow above 20.0 g / 10 minutes, it may be too difficult to shape and mold the ionomer.

[0029] In some examples, neutralization is not conducted with sodium (Na) metal ions.

[0030] The ionomer can additionally include small amounts of additives including plasticizers, stabilizers including viscosity stabilizers, hydrolytic stabilizers, primary and secondary antioxidants, ultraviolet light absorbers, anti-static agents, dyes, pigments or other coloring agents, inorganic fillers, fire-retardants, lubricants, reinforcing agents such as glass fiber and flakes, synthetic (for example, aramid) fiber or pulp, foaming or blowing agents, processing aids, slip additives, antiblock agents such as silica or talc, release agents, tackifying resins, or combinations of two or more thereof. Inorganic fillers, such as calcium carbonate, and the like can also be incorporated into the blend. These additives may be present in the blends in quantities ranging from 0.01 to 40 wt%, 0.01 to 25 wt%, 0.01 to 15 wt%, 0.01 to 10 wt%, or 0.01 to 5 wt%. The incorporation of the additives can be carried out by any known process such as, for example, by dry blending, by extruding a mixture of the various constituents, by the conventional masterbatch technique, or the like.

[0031] According to various examples, the ionomer may be used to form a foam or molded article. For example, the ionomer can be combined with additives used to control foam properties to form foams of various shapes. In some examples, the foam may be extruded, such as from a twin screw extruder, as is known to those of ordinary skill in the art.85548-WO-PCT / DOW 85548 WO

[0032] In some examples, articles comprising the ionomer exhibit a percent elongation of less than or equal to 40.0% under a stress of 14 psi at a temperature of 70 °C over a period of 24 hours. In some examples, articles comprising the ionomer exhibit a percent elongation of less than or equal to 49.5%, less than 35.0%, or less than 30.0% under a stress of 14 psi at a temperature of 70 °C over a period of 24 hours.

[0033] Foaming agents (also referred to as blowing agents) used in the manufacture of foams can be physical foaming agents or chemical foaming agents. As used herein, “physical foaming agents” are low-boiling liquids, which volatilize under the curing conditions to form the blowing gas. Exemplary physical foaming agents include hydrocarbons, fluorocarbons, hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluoroolefins, and other halogenated compounds. Other suitable chemical foaming agents can include, for example, sodium bicarbonate, ammonium bicarbonate, azodicarbonamide, dinitrosopentamethylenediamine, and sulfonyl hydrazides. Foaming agents such as water or carbon dioxide added as a gas or liquid, or generated in-situ by the reaction of water with polyisocyanate, may also be used. The foaming agents can be used in mixtures of two or more, and chemical and physical foaming agents can be used together to tailor expansion-decomposition temperature and foaming processes.

[0034] The foam composition can further include a free radical initiator or crosslinking agents, co-curing agents, an activator, and any other type of additive typically used in similar compositions, including but not limited to pigments, adhesion promoters, fillers, nucleating agents, rubbers, stabilizers, and processing aids.

[0035] Free radical initiators or crosslinking agents can include, by way of example and not limitation, organic peroxides such as dialkyl organic peroxides. Example organic peroxides suitable for use include 1,1-di-t-butyl peroxy-3,3,5-trimethylcyclohexane, t-butyl-cumyl peroxide, dicumyl-peroxide, 2,5-dimethyl-2,5-di(tertiary-butyl-peroxyl)hexane, 1,3-bis(tertiary- butyl-peroxyl-isopropyl)benzene, or combinations of two or more thereof.

[0036] Co-curing agents include trimethyl propane triacrylate (and similar compounds), N,N- m-phenylenedimaleimide, triallyl cyanurate, or combinations of two or more thereof.85548-WO-PCT / DOW 85548 WO

[0037] Activators can include activators for the blowing agent, and can include one or more metal oxides, metal salts, or organometallic complexes. Examples include ZnO, Zn stearate, MgO, or combinations of two or more thereof.

[0038] The foam may be produced by a number of methods, such as compression molding, injection molding, and hybrids of extrusion and molding. The process can include mixing the components of the foam composition under heat to form a melt. The components may be mixed and blended using any technique known and used in the art, including Banbury, intensive mixers, two-roll mills, and extruders. Time, temperature, and shear rate can be regulated to ensure dispersion without premature crosslinking or foaming.

[0039] After mixing, shaping can be carried out. Sheeting rolls or calendar rolls can be used to make appropriately dimensioned sheets for foaming. An extruder may be used to shape the composition into pellets.

[0040] Foaming can be carried out in a compression mold at a temperature and time to complete the decomposition of peroxides and blowing agents. Pressures, molding temperature, and heating time can be controlled. Foaming can be carried out using injection molding equipment by using pellets made from the foam composition. The resulting foam can be further shaped to the dimension of finished products by any means known and used in the art, including thermoforming and compression molding.

[0041] In various examples, the resulting foam composition can be substantially closed cell and useful for a variety of articles, e.g., footwear applications including midsoles or insoles. TEST METHODS

[0042] Melt Index (I2)

[0043] For ethylene-based polymers, melt index (I2) was measured in accordance with ASTM D-1238, Procedure B (condition 190°C / 2.16 kg) and reported in grams eluted per 10 minutes (g / 10 min).85548-WO-PCT / DOW 85548 WO

[0044] Oven Creep Elongation

[0045] Oven creep elongation was measured to determine creep resistance by thoroughly drying the fine powder obtained from each sample for 2 days at 80 °C under a vacuum. The fine powder of the samples was compression molded into 2 mm thick plaques and cut into bars with approximate dimensions of 2.5 inches x 0.5 inches. Bars were marked with a central point and two tick marks centered in the middle of the bar with distance of approximately 1.25 inches. Measurements were taken for each bar – total length, distance between tick marks, thickness and width at the middle. Bars were clamped in a 70 °C oven hanging vertically with a 1000 g weight suspended from the bottom. These samples were allowed to hang for 24 hours, and the % elongation of the distance between the tick marks was tabulated. The results of the oven creep elongation measurements are as shown in Table 1. EXAMPLES

[0046] The following examples are offered by way of illustration and are presented in a manner such that one skilled in the art should recognize are not meant to be limiting to the present disclosure as a whole or to the appended claims.

[0047] The following commercial compositions were used in the Examples below:

[0048] EAC1 is a commercial ethylene / methacrylic acid (MAA) copolymer commercially available from Dow Inc, Midland, MI, was used as a base resin. EAC1 has an MAA content of 15 wt.%.

[0049] EAC2, which is a commercial ethylene / methacrylic acid copolymer commercially available from Dow Inc, Midland, MI, was used as a base resin. EAC2 has an MAA content of 8.7 wt.%.

[0050] The ethylene acid copolymers EAC1 and EAC2 were prepared by standard free-radical copolymerization methods, using high pressure, operating in a continuous manner. Monomers are fed into the reaction mixture in a proportion, which relates to the monomer's reactivity, and the amount desired to be incorporated. In this way, uniform, near-random distribution of monomer85548-WO-PCT / DOW 85548 WO units along the chain is achieved. Polymerization in this manner is well known, and is described in U.S. Pat. No. 4,351,931 (Armitage), which is hereby incorporated by reference. Other polymerization techniques are described in U.S. Pat. No. 5,028,674 (Hatch et al.) and U.S. Pat. No. 5,057,593 (Statz), both of which are also hereby incorporated by reference. The ionomers of these acid copolymers were prepared using the following procedure.

[0051] In a 50 cubic centimeter (cc) RSI bowl, 43g of EAC1 (Samples A1-A15, A18, B1-B6, B9-12, and E1-E6) or EAC2 (Samples C1-C3) was added under N2 purge at a temperature of 200 °C and a mix rate of 100 RPM. After full melting has occurred, the appropriate neutralization salt was added in portions. The amount of neutralization salt needed was determined by the moles of salt required to achieve the desired percent neutralization, wherein each mole of charge of the cation was assumed to neutralize one mole of MAA. N2purge was removed during the addition process to avoid blowing off any fine powder. Once all the neutralization salt had been added, the nitrogen purge was added back, and the reaction was left to proceed for 10 minutes. After this time, the mixing was stopped, and the polymer was collected, cooled, and cut into small chunks and then ground into a fine powder. The various neutralization ions and the neutralization percentage is shown in Table 1. It so noted that sample C11 broke during as it was being measured to determine its oven creep elongation. Table 1: Melt Flow and Oven Creep Elongation85548-WO-PCT / DOW 85548 WO

[0052] A graphical representation of the data of Table 1 is also shown in FIG. 1. Samples C2, C5, C18, and C41-C43 are omitted for clarity.

[0053] As shown in Samples C41-C43, which used EAC2, which has a MAA content of 8.7 wt.%, had a very low elongation creep. This suggests that ionomers with low acid (less than 10 wt.% MAA) have sufficient dimensional stability and do not require neutralization with the cations of the present disclosure to have desirable elongation creep, although the cations of the present disclosure would not be expected to have any negative impact on the melt flow of low acid ionomers.85548-WO-PCT / DOW 85548 WO

[0054] As shown in Samples C9-C14, articles made from ionomers that were neutralized with cations having 3+ and 4+ charges generally showed improved creep resistance compared to Samples C1-C8, which generally had creep resistance above 40% when measured as described herein. However, Samples C9-C14 all had melt flow well below 2.0 g / 10 minutes when measured as described herein. However, as shown in Samples E1-E4, articles made from ionomers that were neutralized using Cs+or La3+, wherein at least 30 mol.% of the MAA was neutralized all had melt flow and creep resistance within the desired parameters. However, when either Cs+or La3+were combined with other cations the resulting ionomers and articles made therefrom had either undesirably low melt flow or undesirably high elongation creep, as shown by Samples C30-C32.

[0055] Additionally, while articles made from ionomer neutralized with mixtures of Na+and Al3+had creep resistance within the desired parameters, these ionomers had undesirably low melt flow, as demonstrated by Samples C21-C26. Nonetheless, when mixtures of aluminum cations and magnesium cations, wherein the mixture included a majority of magnesium cations, where used to neutralize at least 30 mol.% of the MAA in the ionomers, both desired melt flow and desired creep resistance were achieved, as demonstrated by Samples E5 and E6. However, in samples wherein the mixture of aluminum cations and magnesium cations included comprises a majority of aluminum cations, the melt flow fell below desired parameters, as shown by Sample C29.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In case of conflict, the specification, including definitions, will control.

[0057] Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of various examples, suitable methods and materials are described herein.

[0058] Unless stated otherwise, all percentages, parts, ratios, etc., are by weight. When an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of lower preferable values and upper preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any lower range limit or preferred value and any upper range limit or preferred value, regardless of whether ranges are separately disclosed. Where85548-WO-PCT / DOW 85548 WO a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.

[0059] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “containing,” “characterized by,” “has,” “having,” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or.

[0060] The transitional phrase “consisting essentially of” limits the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic(s) of the disclosure. Where applicants have defined an embodiment or a portion thereof with an open-ended term such as “comprising,” unless otherwise stated, the description should be interpreted to also describe such an embodiment using the term “consisting essentially of.”

[0061] Use of “a” or “an” are employed to describe elements and components of various examples. This is merely for convenience and to give a general sense of the various examples. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

Claims

85548-WO-PCT / DOW 85548 WO CLAIMS 1. An ionomer comprising: an ethylene acid copolymer comprising the polymerized reaction product of: from 50 wt.% to 90 wt.% ethylene; from 0 wt.% to 40 wt.% alkyl acrylate; and from 10 wt.% to 20 wt.% monocarboxylic acid monomers; wherein from 30 mol.% to 80 mol.% of acid units are neutralized by: metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150; or a mixture of aluminum cations and magnesium cations, wherein the mixture comprises a majority of magnesium cations; and wherein the ionomer has a melt flow from 2.0 to 20.0 g / 10 minutes as determined according to ASTM D1238 (at 190 °C, 2.16 kg).

2. The ionomer of claim 1, wherein the metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150 have a coordination number of from 3 to 12.

3. The ionomer of claim 1 or claim 2, wherein the metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150 are cesium, lanthanum, rubidium, strontium, or barium.

4. The ionomer of claim 1 or claim 2, wherein the metal cations with ionic radii greater than 100 pm and ionic radii multiplied by ionic charge of greater than 150 are Cs or La.

5. The ionomer of any preceding claim, wherein the neutralization is not conducted with Na metal ions.

6. An article comprising the ionomer of any preceding claim.

7. The article of claim 6, wherein the article is a molded article or a foam.85548-WO-PCT / DOW 85548 WO 8. The article of either of claims 6 or 7, wherein the article exhibits a percent elongation of less than or equal to 40.0% under a stress of 14 psi at a temperature of 70 °C over a period of 24 hours.

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