Method for producing ionomers

Abstract

The present disclosure provides a process for producing an ionomer using a counter rotating twin screw extruder, the process comprising feeding one or more metal cations and an ethylene acid interpolymer into the counter rotating twin screw extruder, the ethylene acid interpolymer comprising a polymerization reaction product of ethylene and an unsaturated carboxylic acid; and producing the ionomer by at least partially neutralizing the ethylene acid interpolymer with the one or more metal cations when the twin screws of the counter-rotating twin screw extruder are rotated relative to each other, and wherein: the twin screws have an aspect ratio of at least 60; the normalized production rate of the double-screw extruder is 0.0014 lb / hr / mm < 3 > to 0.0037 lb / hr / mm < 3 >; the ethylene acid interpolymer has a melt index (I2) of at least 50 dg / min and the ionomer has a melt index of less than 20 dg / min.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority under 35 U.S.C. §119 to U.S. application No. 63 / 411,713, filed on September 30, 2022, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present invention relates to a novel process for producing polymeric ionomer compositions having improved properties. More particularly, the present invention relates to a method for producing ionomers using a counter-rotating twin-screw extruder. Background Art

[0004] Ionomers and methods for producing them are well known in the art. Some ionomers can be formed by neutralization or saponification of interpolymers with metal ions to form metal salts on at least some of these interpolymers. These neutralization or saponification reactions can occur in reactive extrusion processes. Such produced ionomers can be used for high-end applications (including but not limited to film tie layers, heat seal layers, golf and bowling pin covers, automotive bumper guards, side molded strips, shoe parts, packaging films, coatings, adhesives), and for impact modification. Summary of the invention

[0005] However, some ion sources used to produce ionomers may have slow reaction times. Two complications caused by slow reaction times are high melt index and high haze, both of which can indicate incomplete reaction. Incomplete reaction can then result in the ionomer not acquiring the desired properties for suitability in subsequent processes.

[0006] Therefore, there is a need for methods of producing ionomers, which can effectively complete the reaction and obtain the final desired properties, and thus reduce the melt index and minimize the haze. A possible solution to improve the completeness of the ionomer reaction is to increase the residence time of the interpolymer and the metal ion in contact with each other at an elevated melt temperature. Therefore, the chemical reaction can be given more time to proceed to completion and form the desired ionomer. Two expected solutions along these routes are to reduce the production rate of the extruder, or increase the length and outer diameter ratio of the extruder. However, reducing the production rate may not be a suitable solution because it adversely affects the economy of ionomer production. In the commercial-scale automated production of ionomers, this may become an unsustainable limitation because it may increase the cost of the ionomer formed per pound. For similar reasons, batch mixing may not be a suitable solution. In particular, batch mixers may not be suitable for continuous or automated production, which is also a difficult limitation to maintain.

[0007] Therefore, it is desirable to minimize haze while achieving complete reaction (as indicated by a decrease in melt index) without reducing the production rate of the ionomer. Therefore, the method herein produces ionomers in a reactive extrusion process while obtaining the above-mentioned desired results. The method herein achieves the aforementioned by utilizing a counter-rotating twin-screw extruder. The counter-rotating twin-screw extruder can be designed to have a larger screw length to outer diameter ratio (hereinafter referred to as "L / D" ratio), thereby increasing heat transfer between the interpolymer and the metal ion, and allowing a longer residence time at the same rate. Improved heat transfer accelerates the reaction kinetics and increases the melt temperature of the extrusion process, thereby completing more ionomer-forming chemical reactions and reducing haze and melt index. The counter-rotating twin-screw extruder can also be oriented tangentially, which can make the twin screw compatible with even larger L / D ratios.

[0008] According to one embodiment, a method for producing an ionomer using a counter-rotating twin-screw extruder comprises: feeding one or more metal cations and an ethylene acid interpolymer into a counter-rotating twin-screw extruder, the ethylene acid interpolymer comprising a polymerization reaction product of ethylene and an unsaturated carboxylic acid; and producing the ionomer by at least partially neutralizing the ethylene acid interpolymer with the one or more metal cations as the twin screws of the counter-rotating twin-screw extruder rotate relative to each other, and wherein: the aspect ratio of the twin screws is at least 60; the normalized production rate of the twin screw extruder is 0.0014 lb / hr / mm 3 Up to 0.0037lb / hr / mm 3 ; The melt index (I2) of the ethylene acid interpolymer is at least 50 dg / min, and the melt index of the ionomer is less than 20 dg / min.

[0009] Additional features and advantages of the embodiments described herein will be set forth in the following detailed description, and in part will become apparent to those skilled in the art from that description or may be recognized by practicing the described embodiments, including the detailed description and claims provided below. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The following detailed description of specific embodiments of the present disclosure may be best understood when read in conjunction with the accompanying drawings, in which:

[0011] Figure 1 is a schematic representation of a counter-rotating twin-screw extruder according to embodiments herein. DETAILED DESCRIPTION

[0012] Embodiments described herein relate to methods of producing ionomers using a counter-rotating twin-screw extruder.

[0013] Additional features and advantages of the described embodiments will be set forth in the following detailed description, and in part will become apparent to those skilled in the art from the description or may be learned by practicing the described embodiments, including the following detailed description and the claims.

[0014] The term "polymer" refers to a polymeric compound prepared by polymerizing monomers of the same or different types. Thus, the generic term polymer encompasses the term "homopolymer," which generally refers to a polymer prepared from only one type of monomer, and "copolymer," which refers to a polymer prepared from two or more different monomers. As used herein, the term "interpolymer" refers to a polymer prepared by the polymerization of at least two different types of monomers. Thus, the generic term interpolymer includes copolymers or polymers prepared from more than two different types of monomers, such as terpolymers.

[0015] "Ethylene acid interpolymer" is the polymerization reaction product of at least ethylene and one or more unsaturated carboxylic acids, but may also refer to the polymerization reaction product of ethylene, one or more unsaturated carboxylic acids, and additional monomers.

[0016] "Unsaturated carboxylic acid" may also be referred to herein as ethylenically unsaturated carboxylic acid.

[0017] As used herein, "ionomer" is an ethylene acid interpolymer that is at least partially neutralized with a metal cation.

[0018] First reference Figure 1 , a diagram of a counter-rotating twin screw extruder 100 used in an embodiment of the method herein is shown. The twin screw extruder 100 may include a twin screw represented by a first screw 102 and a second screw 104, and may be contained within a housing 120. The twin screw extruder 100 may also include one or more feed mixers 106. One or more feed mixers 106 may be configured to feed the ethylene acid interpolymer stream 202 and the metal cation stream 204 into the twin screw. Water may also be fed into the twin screw extruder with streams 202 and 204 (not shown). In an embodiment, the water may be distilled water. The twin screw may then be able to mix the ethylene acid interpolymer stream 202 and the metal cation stream 204 along the length of the twin screw to produce an ionomer product stream 210.

[0019] The twin screw extruder may also include vents 108 and vents 112 for extracting first vent stream 206 and second vent stream 208 from the twin screw extruder 100. The vents 108 and vents 112 may further include vacuum pumps 110 and 114, respectively. The combination of the vent and vacuum pump may be operable to control devolatilization of the process herein by removing water vapor and carbon dioxide produced as a byproduct of the formation of the ionomer product stream 210. In an embodiment, the rough vacuum of the vacuum pump may be from 10 inches of mercury ("Hg") to about 30 Hg.

[0020] Still reference Figure 1 , the twin screws can be oriented tangentially relative to each other. In other words, the twin screws can be non-intermeshing. It is expected that non-intermeshing rather than intermeshing twin screws can allow longer L / D ratios and higher volumes compatible with the methods herein. This may be due to a reduction in pressure buildup in the previously intermeshing zones of the twin screws. The reduction in pressure buildup can also lead to minimization of screw deflection and reduction in twin screw wear. Therefore, a larger L / D ratio can be obtained using non-intermeshing counter-rotating twin screws.

[0021] As previously mentioned, the twin screws can rotate relative to each other. For example, and in embodiments, when observed at the face of the two screws in the twin screw extruder, both screws can rotate outward or both twin screws can rotate inward. Rotating the twin screws relative to each other can further include rotating the twin screws at least 150 revolutions per minute (RPM). Rotating the twin screws can also be carried out with 100rpm to 800rpm, 100rpm to 550rpm, 100rpm to 450rpm, 100rpm to 345rpm, 100rpm to 250rpm or any combination of ranges therein or a smaller range of RPM.

[0022] In an embodiment, the twin screws may each further include a barrel, a screw element, and one or more mixing elements. The screw element can inhale and convey the material. One or more mixing elements 160, 162, 164 can input energy into the material to melt and mix and increase the material temperature for reaction. In this way, one or more mixing sections 160, 162, 164 can be operated to mix the ethylene acid interpolymer stream 202 and the metal cation stream 204. The mixing element may include, but is not limited to, one or more kneading elements, one or more slotted screw elements (which may be left-handed or right-handed), one or more bubble rings, one or more cylindrical mixing elements, one or more pineapple mixing elements, one or more diamond mixing elements, or a combination thereof.

[0023] The one or more mixing elements may contact and extend from the outer surface of the barrel, which may also be referred to as the radial edge of the barrel (separated only by the gap). In doing so, the two screws in the twin screw extruder may each have an outer diameter and an inner diameter. The outer diameter may be measured from the radial center of the screw to the radial edge of the mixing element (separated only by the gap). The inner diameter may be measured from the radial center of the screw to the root of the screw. The outer diameter of a counter-rotating twin screw extruder may vary from 20 mm to 300 mm.

[0024] In an embodiment, the length to outer diameter ratio (L / D ratio) of the twin screw may be at least 60. It is expected that a length to outer diameter ratio of at least 60 may be significant because the ratio can provide the necessary residence time and heat transfer between the interpolymer and the metal cation to increase the melt temperature of the extrusion process and complete the reaction. The length to outer diameter (L / D) ratio of the twin screw may also be 60 to 120, 60 to 110, 60 to 100, 60 to 90, 60 to 80, 60 to 70, or ranges therein or smaller.

[0025] In an embodiment, the counter-rotating twin screw extruder 100 may be heated. The counter-rotating twin screw extruder 100 may be heated by the barrel, by the mixing element, or by both. The counter-rotating twin screw extruder 100 may be heated to a temperature of 70°C to 280°C, 150°C to 280°C, 190°C to 280°C, 220°C to 280°C, 240°C to 280°C, or any combination of ranges therein or a smaller range. In an embodiment, the temperature of the counter-rotating twin screw extruder may be limited only by the degradation temperature of the ethylene acid terpolymer.

[0026] The counter-rotating twin-screw extruder may also include one or more zones. The one or more zones may each be heated at different temperatures so that the contents in the extruder are heated at different temperatures in each of the one or more zones. Each subsequent zone may be at a higher temperature than the previous zone. For example, and in an embodiment, one or more zones may include at least five zones. The first zone 140 may be heated at a temperature of 10°C to 280°C. The second zone 142 may be heated at a temperature of 70°C to 280°C. The third zone 144 may be heated at a temperature of 150°C to 280°C. The fourth zone 146 may be heated at a temperature of 190°C to 280°C. The fifth zone 148 may be heated at a temperature of 220°C to 240°C or 220°C to 280°C.

[0027] As previously described, embodiments herein relate to methods for producing ionomers using a counter-rotating twin-screw extruder. Any of the foregoing embodiments of the twin-screw extruder 100 can be used in the methods below. The method initially includes feeding one or more metal cations and ethylene acid interpolymers into a counter-rotating twin-screw extruder. The method further includes producing the ionomer by at least partially neutralizing the ethylene acid interpolymer with the one or more metal cations while the twin screws of the counter-rotating twin-screw extruder rotate relative to each other.

[0028] As previously mentioned, the ethylene acid interpolymer may include the polymerization product of ethylene and unsaturated carboxylic acid. Also as previously mentioned, the ethylene acid interpolymer may further include another monomer. For example, and in an embodiment, the additional monomer may include, but is not limited to, acrylate, methacrylate, or both. Various comonomers containing unsaturated carboxylic acids may also be utilized in the ethylene acid interpolymer. For example, the comonomer containing unsaturated carboxylic acids may include monocarboxylic acids, which may include acrylic acid, methacrylic acid, or both. In an embodiment, the ethylene acid interpolymer may be a polymerization product of 70% to 85% by weight of ethylene and 15% to 30% by weight of unsaturated carboxylic acids, based on the total weight of the monomers present in the ethylene acid interpolymer. All individual values ​​and ranges are included and disclosed herein. For example, in some embodiments, the ethylene acid interpolymer may be a polymerization product of 72% to 85% by weight of ethylene, based on the total weight of the monomers present in the ethylene acid interpolymer; and 15% to 28% by weight of unsaturated carboxylic acids. In other embodiments, the ethylene acid interpolymer can be the polymerization product of 75 to 85 weight percent ethylene; and 15 to 25 weight percent unsaturated carboxylic acid, based on the total weight of the monomers present in the ethylene acid interpolymer. In other embodiments, the ethylene acid interpolymer can be the polymerization product of 79 to 82 weight percent ethylene; and 18 to 21 weight percent unsaturated carboxylic acid, based on the total weight of the monomers present in the ethylene acid interpolymer.

[0029] Ethylene acid interpolymers may be polymerized according to the processes disclosed in U.S. Patent Nos. 3,404,134; 5,028,674; 6,500,888; and 6,518,365. In some embodiments, blends of two or more ethylene acid interpolymers may be used, provided that the aggregate components and properties of the blend fall within the limits described above for ethylene acid interpolymers.

[0030] Optionally, the ethylene acid interpolymer can be at least partially neutralized before being fed to the counter-rotating twin-screw extruder. As used herein, neutralization is defined as the neutralization percentage of the total acid units. Referring to the neutralized total acid units, the calculation of the neutralization percentage is based on the number of acid units believed to be present, based on the known molar amount of the unsaturated carboxylic acid and the molar equivalent number of the one or more metal cations added. In embodiments herein, 0.01 mol % to 100 mol % of the total acid units of the ethylene acid interpolymer are neutralized by one or more metal cations. All individual values ​​and subranges are included and disclosed herein. In other embodiments, 1 mol % to 95 mol %, 10 mol % to 90 mol % or 50 mol % to 90 mol % of the total acid units can be neutralized.

[0031] The melt index (I2) of the ethylene acid interpolymer may be at least 50 decigrams per minute (dg / min) measured according to ASTM D1238 (at 190°C, 2.16 kg). The melt index is generally understood to be an indirect measure of the molecular weight of the ethylene acid interpolymer. A higher melt index indicates a low molecular weight, and vice versa. In an embodiment, the melt index of the ethylene acid interpolymer may also be from 50 dg / min to 200 dg / min, from 50 dg / min to 150 dg / min, from 50 dg / min to 125 dg / min, from 50 dg / min to 100 dg / min, from 50 dg / min to 75 dg / min, from 50 dg / min to 60 dg / min, or any combination of ranges therein or smaller ranges.

[0032] In the method herein, the melt index (I2) of the produced ionomer may be less than 20 dg / min. The melt index of the produced ionomer may also be 1 dg / min to 20 dg / min, 1 dg / min to 18 dg / min, 1 dg / min to 12 dg / min, 1 dg / min to 8 dg / min, 1 dg / min to 4 dg / min, or any combination of ranges or smaller ranges therein. It is expected that a melt index less than 20 dg / min is desired because the melt index may also be used as a relative indicator of reaction completeness. For example, when the reaction completeness increases, a melt index decrease is also observed. In commercial-scale automated production, the melt index may be used accordingly as a faster online measurement of haze rather than a more time-consuming visual inspection.

[0033] In an embodiment, the haze of the ionomer may be less than 20%. As previously mentioned, the haze of the ionomer is generally understood to represent the completeness of the chemical reaction that forms the ionomer. When the haze (opacity) increases, it is believed that the completeness of the chemical reaction that forms the ionomer decreases, and vice versa. In an embodiment, the haze of the ionomer may be 1 to 20, 1 to 18, 1 to 12, 1 to 8, 1 to 4, or any combination of ranges therein or smaller ranges.

[0034] As previously mentioned, the reagent for neutralizing the acid units of the ethylene acid interpolymer may include a metal cation or a combination of two or more metal cations. The one or more metal cations may include alkaline earth metals. For example, and in an embodiment, the one or more metal cations may include calcium, zinc, magnesium, or a combination thereof. In one embodiment, the one or more metal cations include zinc. The one or more metal cations, such as zinc, may be suspended in the ethylene acid interpolymer as a masterbatch; however, various mechanisms for delivering one or more metal cations for neutralization are considered suitable. The acid interpolymer may be an ethylene acid interpolymer, or it may be a second ethylene acid interpolymer. The melt index of the second ethylene acid interpolymer may be at least 500 dg / min. The second ethylene acid interpolymer can have a melt index of 500 dg / min to 3000 dg / min, 500 dg / min to 2500 dg / min, 500 dg / min to 2000 dg / min, 500 dg / min to 1500 dg / min, or 500 dg / min to 1000 dg / min, or any combination of ranges therein or smaller ranges.

[0035] As previously discussed, the counter-rotating twin-screw extruder may be heated. In embodiments where the extruder is heated, the one or more metal ions and the ethylene acid interpolymer may be heated within the twin-screw extruder at a temperature of 70° C. to 280° C., or at any temperature range discussed previously, whether generally within the twin-screw extruder or within one or more zones of the twin-screw extruder.

[0036] In an embodiment, the method may further include extruding the ionomer into pellets. For a 50 mm tangential counter-rotating twin screw extruder, the extrusion rate of the ionomer can be 200 pounds per hour to 450 pounds per hour. For a 50 mm tangential counter-rotating twin screw extruder, the extrusion rate can also be 200 to 450, 200 to 400, 200 to 350, 200 to 300, 200 to 250, or any combination of ranges therein or a smaller range. For counter-rotating twin screw extruders of other outer diameters, the volumetric capacity can be defined as the ratio of the extrusion rate of the ionomer to the cube of the outer diameter. Thus, the volumetric capacity of a counter-rotating twin screw extruder can be 0.0014 lb / hr / mm 3 Up to 0.0037lb / hr / mm 3 The volume capacity of a counter-rotating twin-screw extruder can be 0.001 lb / hr / mm 3 To 0.0050lb / hr / mm 3 、0.001lb / hr / mm 3 Up to 0.004lb / hr / mm 3、0.001lb / hr / mm 3 Up to 0.003lb / hr / mm 3 、0.001lb / hr / mm 3 To 0.002lb / hr / mm 3 , or any combination of ranges therein or smaller ranges.

[0037] In an embodiment, and as previously described, the method can also include feeding water or a metal salt solution (e.g., zinc acetate) into a counter-rotating twin-screw extruder. The ionomer on one or more vent streams can then be produced by at least partially neutralizing the ethylene acid interpolymer with one or more metal cations while the twin screws of the counter-rotating twin-screw extruder rotate relative to each other in the presence of water. The one or more vent streams can include water vapor, carbon dioxide, or both. The one or more vent streams can be extracted by one or more vents of the counter-rotating twin-screw extruder. The extraction method can be by vent 108 and vent 112 through vacuum pump 110 and vacuum pump 114, as previously described.

[0038] Test Method

[0039] Melt index (I2 )

[0040] For ethylene-based polymers, melt index (I2) is measured according to ASTM D-1238, Procedure B (Condition 190°C / 2.16 kg) and is reported in decigrams eluted per 10 minutes (dg / min).

[0041] Haze

[0042] Haze was measured according to ASTM D1003. Haze is generally measured as the percentage of incident light that is scattered greater than 2.5 degrees by the ionomer. Haze was measured on compression molded 0.125" plaques molded at 190°C using a Carver press and a plaque mold with Mylar sheet inserts on both sides.

[0043] Moisture content

[0044] Moisture content was measured at 150°C according to ASTM D6869.

[0045] Zinc oxide content

[0046] Energy dispersive X-ray fluorescence (XRF) spectroscopy was performed to detect the total zinc content in the ionomer product. An Oxford Twin X benchtop analyzer was used. The following conditions were used for measurement: 26 kV, 40 uA excitation, Z1 primary filter, no secondary filter, PIN detector, ROI of 8.44 kV to 8.82 kV for zinc, ROI of 15 kV to 20 kV for backscattering, 180 seconds analysis time, and the medium was air. The measurement was performed in the following manner: first, the sample cup was assembled with a Chemplex 6 μm Mylar polyester x-ray film. The sample cup was then filled with ionomer pellets until or just above the indicator line and covered. The cup was shaken to allow the pellets to settle on the membrane and then loaded into the instrument's carousel for analysis.

[0047] Example

[0048] Ionomers were formed according to embodiments herein and compared to ionomers formed using different parameters and types of extruders. The compositions of the components of the ionomers used in the examples are shown below in Table 1. The metal cation was 45 wt% zinc oxide suspended in an ethylene acid interpolymer carrier.

[0049] Table 1: Ionomer Composition

[0050]

[0051] Ethylene acid interpolymers are prepared by standard free radical interpolymerization methods, using high pressure, operating in a continuous manner. The monomers are fed to the reaction mixture in a ratio related to the monomer reactivity and the desired incorporation amount. In this way, a uniform, nearly random distribution of monomer units along the chain is achieved. Polymerization performed in this manner is well known and is described in U.S. Patent No. 4,351,931 (Armitage), which is hereby incorporated by reference. Other polymerization techniques are described in U.S. Patent No. 5,028,674 (Hatch et al.) and U.S. Patent No. 5,057,593 (Statz), which are hereby incorporated by reference. Table 1 below provides additional aspects of the ionomers. The ionomers of these acid interpolymers are prepared as described above.

[0052] The ethylene acid interpolymer and the metal ions for each of the above ionomers were fed into a 2 inch (50.8 mm) outer diameter 83 L / D tangential counter-rotating twin-screw extruder (obtained from NFM Welding Engineers of Massillon, OH) using two K-TRON loss-in-weight feeders. Distilled water was fed into the twin-screw extruder using a Milton Roy piston pump with a double-head design. The twin-screw extruder further included two vents, and a 20 horsepower Busch vacuum pump to devolatilize the twin-screw extruder. The ionomer pellets were discharged using a Gala reversing valve and a Gala 6 underwater pelletizer. Prior to packaging and sealing in aluminum bags until testing, the pellets were discharged onto a cooling classifier for drying. According to the embodiments of the present invention, the twin-screw extruder was also heated in five zones. The zone temperatures are shown in Table 2 below. Additional processing details for ionomer 1 and ionomer 2 are provided in Table 3 and Table 4, respectively. As shown in Tables 3 and 4, additional comparative samples were prepared using either a tandem single screw extruder or a co-rotating twin screw extruder having components similar to the tangential counter-rotating twin screw extruder.

[0053] Table 2: Extruder zone temperatures

[0054]

[0055] Table 3: Processing parameters for Ionomer 1 Example

[0056]

[0057] Table 4: Processing parameters for Ionomer 2 Example

[0058]

[0059] Table 5: Test results of ionomer 1 example

[0060]

[0061] Table 6: Test results of ionomer 2 example

[0062]

[0063] As shown in the examples with Ionomer 1 and Ionomer 2 in Tables 5 and 6, respectively, tangential counter-rotating twin-screw extruders with L / D of 72 and 83 produced ionomers with lower haze than the equivalent ionomer produced by a co-rotating twin-screw extruder with L / D of 48. Specifically, all counter-rotating twin-screw extruders produced haze values ​​of less than 20% and a clear plaque appearance. The counter-rotating twin-screw extruders also produced ionomers with lower melt indices than the comparative examples, on average. The lower melt indices in Tables 5 and 6 are also lower than the melt indices of the corresponding base resins, indicating reaction and ionomer formation. In addition, the counter-rotating twin-screw extruders also produced ionomers with lower moisture content, on average, than the comparative examples.

[0064] Embodiments herein may include one or more aspects. According to a first aspect, a method for producing an ionomer using a counter-rotating twin-screw extruder comprises: feeding one or more metal cations and an ethylene acid interpolymer into the counter-rotating twin-screw extruder, the ethylene acid interpolymer comprising a polymerization reaction product of ethylene and an unsaturated carboxylic acid; and producing the ionomer by at least partially neutralizing the ethylene acid interpolymer with the one or more metal cations as the twin screws of the counter-rotating twin-screw extruder rotate relative to each other, and wherein: the aspect ratio of the twin screws is at least 60; the normalized production rate of the twin screw extruder is 0.0014 lb / hr / mm 3 Up to 0.0037lb / hr / mm 3 ; The melt index (I2) of the ethylene acid interpolymer is at least 50 dg / min, and the melt index of the ionomer is less than 20 dg / min.

[0065] A second aspect includes any of the preceding aspects, and may further include extruding the ionomer into pellets.

[0066] A third aspect includes any of the preceding aspects, wherein the ionomer has a haze of less than 20%.

[0067] A fourth aspect includes any of the preceding aspects, wherein the one or more metal cations comprise an alkaline earth metal.

[0068] A fifth aspect includes any of the preceding aspects, wherein the ethylene acid interpolymer comprises an interpolymer of ethylene and (meth)acrylic acid.

[0069] A sixth aspect includes any of the preceding aspects, wherein the one or more metal cations include zinc.

[0070] A seventh aspect includes any of the preceding aspects, wherein the zinc is suspended in the second ethylene acid interpolymer having an I2 of at least 500 dg / min.

[0071] An eighth aspect includes any of the preceding aspects, wherein the two screws in the counter-rotating twin-screw extruder are oriented tangentially relative to each other.

[0072] A ninth aspect includes any of the preceding aspects, wherein the ethylene acid interpolymer is an ionomer that is at least partially neutralized prior to feeding.

[0073]

[0013] A tenth aspect includes any of the preceding aspects, wherein the one or more metal ions and the ethylene acid interpolymer within the counter-rotating twin-screw extruder are heated at a temperature of 70°C to 280°C.

[0074] The eleventh aspect includes any of the preceding aspects, wherein the counter-rotating twin-screw extruder has five separate zones, wherein: the temperature of the first zone is 10°C to 280°C; the temperature of the second zone is 70°C to 280°C; the temperature of the third zone is 150°C to 280°C; the temperature of the fourth zone is 190°C to 280°C; and the temperature of the fifth zone is 220°C to 280°C.

[0075] A twelfth aspect includes the tenth aspect, wherein each subsequent zone is at a higher temperature than a previous zone.

[0076] A thirteenth aspect includes any of the preceding aspects, wherein rotating the twin screws relative to each other further comprises rotating the twin screws at 150 revolutions per minute (RPM) to 800 RPM.

[0077] A fourteenth aspect includes any of the preceding aspects, wherein the extrusion rate of the ionomer is from 200 lbs / hr to 450 lbs / hr.

[0078] A fifteenth aspect includes any of the preceding aspects, and further includes feeding water into the counter-rotating twin-screw extruder; producing the ionomer and one or more vent streams by at least partially neutralizing the ethylene acid interpolymer with the one or more metal cations in the presence of water while the twin screws of the counter-rotating twin-screw extruder rotate relative to each other; and extracting the one or more vent streams through one or more vent ports of the counter-rotating twin-screw extruder, the one or more vent streams comprising water vapor and carbon dioxide.

[0079] It should be noted that, unlike statements of intended use, statements in the present disclosure that a component of the present disclosure is "operable" or "sufficient" in a particular manner to embody a particular characteristic or function in a particular manner are structural statements. More specifically, references in the present disclosure to the manner in which a component is "operable" or "sufficient" refer to the existing physical condition of the component and, therefore, will be regarded as an explicit statement of the structural characteristics of the component.

[0080] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0081] Ranges are provided throughout the disclosure. It is anticipated that each discrete value encompassed by these ranges is also included. In addition, ranges formed by each discrete value encompassed by the explicitly disclosed ranges are also anticipated.

[0082] As used in this disclosure and the appended claims, the words "comprising," "having," and "including" and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps.

[0083] As used in this disclosure, terms such as "first" and "second" are arbitrarily designated and are intended only to distinguish between two or more instances or components. It should be understood that the words "first" and "second" have no other purpose and are not part of the component name or description, nor do they necessarily define the relative positioning, location, or order of the components. In addition, it should be understood that the use of the terms "first" and "second" alone does not require the existence of any "third" component, although such a possibility is contemplated within the scope of this disclosure.

[0084] The subject matter of the present disclosure has been described in detail and by reference to specific embodiments, it should be noted that the various details disclosed in the present disclosure should not be considered to imply that these details relate to elements that are essential parts of the various embodiments described in the present disclosure. In addition, it is apparent that modifications and changes can be made without departing from the scope of the present disclosure including but not limited to the embodiments defined in the appended claims.

Claims

1. A method for producing an ionomer using a counter-rotating twin-screw extruder, the method comprising: feeding one or more metal cations and an ethylene acid interpolymer comprising a polymerization reaction product of ethylene and an unsaturated carboxylic acid into the counter-rotating twin-screw extruder; as well as The ionomer is produced by at least partially neutralizing the ethylene acid interpolymer with the one or more metal cations while the twin screws of the counter-rotating twin-screw extruder rotate relative to each other, and wherein: The twin screw has an aspect ratio of at least 60; The normalized production rate of the twin-screw extruder was 0.0014 lb / hr / mm 3 Up to 0.0037lb / hr / mm 3 ; The ethylene acid interpolymer has a melt index (I2) of at least 50 dg / min and the ionomer has a melt index of less than 20 dg / min. 2 . The method of claim 1 , further comprising extruding the ionomer into pellets.

3. A method according to any preceding claim, wherein the ionomer has a haze of less than 20%.

4. A method according to any preceding claim, wherein the one or more metal cations comprise an alkaline earth metal.

5. The method of any preceding claim, wherein the ethylene acid interpolymer comprises an interpolymer of ethylene and (meth)acrylic acid.

6. A method according to any preceding claim, wherein the one or more metal cations comprises zinc.

7. The method of claim 6, wherein the zinc is suspended in the second ethylene acid interpolymer at an I2 of at least 500 dg / min.

8. A method according to any preceding claim, wherein the two screws in the counter-rotating twin-screw extruder are oriented tangentially relative to each other.

9. The process according to any preceding claim, wherein the ethylene acid interpolymer is an ionomer that is at least partially neutralized prior to feeding.

10. The process of any preceding claim, wherein the one or more metal ions and the ethylene acid interpolymer within the counter-rotating twin-screw extruder are heated at a temperature of 70°C to 280°C.

11. A process according to any preceding claim, wherein the counter-rotating twin-screw extruder has five separate zones wherein: The temperature of the first zone is 10°C to 280°C; The temperature of the second zone is 70°C to 280°C; The temperature of the third zone is 150°C to 280°C; The temperature of the fourth zone is 190°C to 280°C; and The temperature of the fifth zone is 220°C to 280°C.

12. The method of claim 10, wherein each subsequent zone is at a higher temperature than the previous zone.

13. The method of any preceding claim, wherein rotating the twin screws relative to each other further comprises rotating the twin screws at 150 revolutions per minute (RPM) to 800 RPM.

14. The method of any preceding claim, wherein the extrusion rate of the ionomer is from 200 pounds per hour to 450 pounds per hour.

15. The method according to any preceding claim, further comprising: feeding water into the counter-rotating twin-screw extruder; producing the ionomer and one or more vent streams by at least partially neutralizing the ethylene acid interpolymer with the one or more metal cations in the presence of water while the twin screws of the counter-rotating twin-screw extruder rotate relative to each other; as well as The one or more vent streams are extracted through one or more vent ports of the counter-rotating twin-screw extruder, the one or more vent streams comprising water vapor and carbon dioxide.

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