Epoxide-functionalized polyolefins

Abstract

The present disclosure provides embodiments of an epoxide-functionalized polyolefin including an ethylene-based polymer grafted with an epoxide-containing monomer having the following structure: wherein: R is a methyl, ethyl, propyl, or butyl group; n is from 1 to 8; and the ethylene-based polymer is the polymerized reaction product of ethylene and optionally at least one additional comonomer selected from C3-C12 alpha-olefins or polar comonomers.

Description

EPOXIDE -FUNCTIONALIZED POLYOLEFINSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 664,942 filed June 27, 2024, the contents of which are incorporated in their entirety herein.TECHNICAL FIELD

[0002] The present disclosure generally relates epoxide-functionalized polyolefins and specifically relate to ethylene-based polymers grafted with an epoxide-containing monomer having increased grafting efficiency.BACKGROUND

[0003] Epoxide-functionalized polyolefins are valuable for applications such as asphalt modification, recycling compatibilizers, and impact modifiers. However, polar monomers are incompatible with solution, slurry, and gas phase coordination olefin polymerization processes, limiting their use in these methods. While high-pressure processes can accommodate polar monomers, they are typically restricted to EDPE-like architectures and require substantial capital investment. Post-reactor grafting offers a solution, enabling the production of epoxide-functional polyolefins across a broad compositional range with lower capital investment. This approach overcomes compatibility issues associated with traditional processes and enhances the functional properties of polyolefins.SUMMARY

[0004] The development of new epoxide-functionalized polyolefins is driven by the limitations associated with current monomers available for grafting epoxide functionality. One of the primary challenges is the limited selection of suitable monomers, which impacts the efficiency and effectiveness of the grafting process. For instance, glycidyl methacrylate (GMA) is commonly used due to its availability and cost-effectiveness. However, GMA suffers from low grafting efficiency, leading to significant homopolymer formation and limiting the epoxide content in the final polymer. This inefficiency results in increased production costs due to low conversion rates and management of unwanted byproducts.

[0005] Glycidyl methacrylate remains the most prevalent acrylic monomer with an epoxide group for grafting to polyolefins, primarily because it is commercially available and inexpensive. Despite these advantages, its drawbacks, such as low grafting efficiency and the propensity for homopolymerization, hinder its effectiveness. The low efficiency not only restricts the achievable epoxide content in the polymer but also results in additional processing steps and costs. Therefore, there is a need for new epoxide-functionalized polyolefins that can overcome these limitations, offering improved grafting efficiencies and reduced byproduct formation to enhance performance and cost-effectiveness in industrial applications.

[0006] Embodiments of the present disclosure address these and other issues by grafting an epoxide-containing monomer having the following structure on an ethylene-based polymer:wherein: R is a methyl, ethyl, propyl, or butyl group, n is from 1 to 8, and the ethylene-based polymer is the polymerized reaction product of ethylene and optionally at least one additional comonomer selected from C3-C12 alpha-olefins or polar comonomers.

[0007] An ethylene-based polymer grafted with this epoxide-containing monomer, which encompasses monomers such as glycidyl crotonate, results in higher grafting efficiencies and lower ungrafted-byproducts than GMA due to homopolymerization.

[0008] According to one or more embodiments of the present disclosure, an epoxide- functionalized polyolefin comprising ethylene-based polymer grafted with an epoxide-containing monomer having the above structure is provided herewith.

[0009] Additional features and advantages 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 orrecognized by practicing the embodiments described herein, including the detailed description which follows in addition to the claims.

[0010] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter.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] Definitions

[0013] The term “composition,” as used herein, includes a material or mixture of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition. Typically, any reaction products and / or decomposition products are present in trace amounts.

[0014] 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.

[0015] “Polyethylene” or “ethylene-based polymer” shall mean polymers comprising greater than or equal to 50% by mole of units derived from ethylene monomer. This includes ethylenebased 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, Tow Density Polyethylene (TDPE); Tinear Tow Density Polyethylene (TTDPE); 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).

[0016] The term “LLDPE,” includes resin made using Ziegler-Nata catalyst systems as well as resin made using single-site catalysts, including, but not limited to, bis-metallocene catalysts (sometimes referred to as “m-LLDPE”), phosphinimine, and constrained geometry catalysts, and resins made using post-metallocene, molecular catalysts, including, but not limited to, bis(biphenylphenoxy) catalysts (also referred to as polyvalent aryloxy ether catalysts). LLDPE includes linear, substantially linear, or heterogeneous ethylene-based copolymers or homopolymers. LLDPEs contain less long chain branching than LDPEs and include the substantially linear ethylene polymers, which are further defined in U.S. Patent No. 5,272,236, U.S. Patent No. 5,278,272, U.S. Patent No. 5,582,923 and U.S. Patent No. 5,733,155; the homogeneously branched linear ethylene polymer compositions such as those in U.S. Patent No. 3,645,992; the heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Patent No. 4,076,698; and blends thereof (such as those disclosed in U.S. Patent No. 3,914,342 and U.S. Patent No. 5,854,045). The LLDPE resins can be made via gas-phase, solution-phase, or slurry polymerization or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0017] The term “HDPE” refers to ethylene-based polymers having densities greater than about 0.940 g / cc, which are generally prepared with Ziegler-Natta catalysts, chrome catalysts or even metallocene catalysts.

[0018] For the purposes of describing and defining the present invention, it is noted that recitations herein of “at least one” component, element, etc., should not be used to create an inference that the alternative use of the articles “a” or “an” should be limited to a single component, element, etc. For example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0019] It is noted that terms like “preferably,” “commonly,” and “typically,” when utilized herein, are not utilized to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to identify particular aspects of an embodiment of the present disclosure or to emphasize alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure.

[0020] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0021] Embodiments of the present disclosure are directed to an epoxide-functionalized polyolefin comprising ethylene-based polymer grafted with an epoxide-containing monomer having the above structure:wherein: R is a methyl, ethyl, propyl, or butyl group, n is from 1 to 8, and the ethylene-based polymer is the polymerized reaction product of ethylene and optionally at least one additional comonomer selected from C3-C12 alpha-olefins or polar comonomers.

[0022] Ethylene-Based Polymer

[0023] In embodiments, ethylene-based polymer may be the polymerized reaction product of ethylene and optionally at least one additional comonomer. The additional comonomer may beselected from C3-C12 alpha-olefins or polar comonomers. In embodiments where the additional comonomer is selected from C3-C12 alpha-olefins, the ethylene-based polymer may be an ethylene / alpha-olefin copolymer, wherein the alpha-olefin is a C3-C12 alpha-olefin or a C4-C8 alpha-olefin. These polar comonomers may include but are not limited to those with carboxylic acid, acrylate, or acetate functionality, for example, methacrylic acid, acrylic acid, vinyl acetate, methyl acrylate, isobutyl acrylate, n-butyl acrylate, and monoethyl ester of maleic acid.

[0024] In various embodiments, the ethylene -based polymer may be an ethylene / alpha-olefin block copolymer. Commercial examples of ethylene / alpha-olefin block copolymer include resins available under the trade name INFUSE™, available from The Dow Chemical Company (Midland, MI).

[0025] In various embodiments, the ethylene / alpha-olefin block copolymer may comprise ethylene and one or more copolymerizable alpha-olefin monomers in polymerized form, characterized by multiple blocks or segments of two or more polymerized monomer units differing in chemical or physical properties. The polyolefin elastomers can be multi-block copolymers. In one or more embodiments, the multi-block copolymer can be represented by the formula (AB)n where n is at least 1, preferably an integer greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, “A” represents a hard block, and “B” represents a soft block. In embodiments, As and Bs are linked in a substantially linear fashion, as opposed to a substantially branched or substantially star-shaped fashion. In one or more embodiments, A blocks and B blocks are randomly distributed along the polymer chain and do not have a structure as follows: AAA-AA-BBB-BB. In some embodiments, the block copolymers do not have a third type of block, which comprises different comonomers. In embodiments, each of block A and block B has monomers or comonomers substantially randomly distributed within the block, such that neither block A nor block B comprises two or more sub-segments of distinct composition, such as a tip segment, that has a substantially different composition than the rest of the block.

[0026] The ethylene / alpha-olefin block copolymer can include various amounts of “hard” and “soft” blocks. “Hard” blocks refer to blocks of polymerized units in which ethylene is present in an amount greater than about 95 wt.%, and preferably greater than about 98 wt.%, based on the weight of the polymer. In other words, the comonomer content, i.e., the content of monomersother than ethylene, in the hard blocks is less than about 5 wt.%, and preferably less than about 2 wt.%, based on the weight of the polymer. In one or more embodiments, the hard blocks comprise all or substantially all ethylene. “Soft” blocks, on the other hand, refer to blocks of polymerized units in which the comonomer content, i.e., the content of monomers other than ethylene, is greater than about 5 wt.%. For example, the comonomer content may be greater than about 5 wt.%, greater than about 8 wt.%, greater than about 10 wt.%, or greater than about 15 wt.%, based on the weight of the polymer. In various embodiments, the comonomer content in the soft blocks can be greater than about 20 wt.%, greater than about 25 wt.%, greater than about 30 wt.%, greater than about 35 wt.%, greater than about 40 wt.%, greater than about 45 wt.%, greater than about 50 wt.%, or greater than about 60 wt.%, based on the weight of the polymer.

[0027] In various embodiments, the soft blocks are present in the ethylene / alpha-olefm block copolymer at amounts from about 1 wt.% to about 99 wt.% of a total weight of the polyolefin elastomer. For example, the soft blocks can be present in the ethylene / alpha-olefm block copolymer from about 5 wt.% to about 95 wt.%, from about 10 wt.% to about 90 wt.%, from about 15 wt.% to about 85 wt.%, from about 20 wt.% to about 80 wt.%, from about 25 wt.% to about 75 wt.%, from about 30 wt.% to about 70 wt.%, from about 35 wt.% to about 65 wt.%, from about 40 wt.% to about 60 wt.%, or from about 45 wt.% to about 55 wt.% of the total weight of the ethylene / alpha-olefm block copolymer. Conversely, the hard blocks can be present in similar ranges. The soft block and hard block weight percentages can be calculated based on data obtained from DSC or NMR. Such methods and calculations are disclosed in U.S. Patent Application Publication No. 2006 / 0199930.

[0028] In embodiments, the ethylene-based polymer has a density greater than or equal to 0.850 and less than or equal to 0.950, greater than or equal to 0.860 less than or equal to 0.940, greater than or equal to 0.870 and less than or equal to 0.930, greater than or equal to 0.880 and less than or equal to 0.925, greater than or equal to 0.890 and less than or equal to 0.920, or greater than or equal to 0.900 and less than or equal to 0.910 g / cc (g / cc = g / cm3). In embodiments, the ethylene-based polymer has a density greater than or equal to 0.850, greater than or equal to 0.855, greater than or equal to 0.860, or greater than or equal to 0.865 g / cc. In embodiments, the ethylenebased polymer has a density from 0.850 to 0.950 g / cc.

[0029] Epoxide-Containing Monomer

[0030] In embodiments, the epoxide-containing monomer has the following structure, according to formula (I):

[0031] R may be a methyl, ethyl, propyl, or butyl group, and n may range from 1 to 8. For example, n may be 1, 2, 3, 4, 5, 6, 7, or 8. In embodiments, the epoxide-containing monomer may be glycidyl crotonate, having a structure according to formula (II):

[0032] In embodiments, an epoxy-functionalized ethylene -based polymer is made by initiating a free radical grafting reaction between the ethylene-based polymer and the epoxide-containing monomer in the presence of a radical initiator to produce the ethylene-based polymer grafted with epoxide-containing monomer. In embodiments, the epoxide-containing monomer is fed in an amount from 0.5 wt.% to 10 wt. % relative to the feed of the ethylene-based polymer. In embodiments, the radical initiator is fed in an amount of from 0.075 wt.% to 1.0 wt. % relative to the feed of the ethylene-based polymer.

[0033] In embodiments, the free radical grafting reaction may be carried out in a melt phase at a temperature greater than or equal to 100 °C and less than or equal to 300 °C. In embodiments, the free radical grafting reaction may be carried out in a melt phase at a temperature greater than or equal to 120 °C and less than or equal to 280 °C, greater than or equal to 140 °C and less than or equal to 260 °C, greater than or equal to 160 °C and less than or equal to 240 °C, greater than or equal to 180 °C and less than or equal to 220 °C, or greater than or equal to 200 °C and less than or equal to 210 °C. All individual values and subranges from 100 °C to 300 °C are included herein and disclosed herein.

[0034] Various radical initiators are considered suitable. In one or embodiments, the radical initiator comprises peroxide. Suitable peroxides include, but are not limited to, the following: LUPEROX 101 (2,5-dimethyl-2,5-di(t-butylperoxy) hexane) CAS # 78-63-7; LUPEROX DC (dicumyl peroxide), CAS #80-43-3; LUPEROX DTA (di(t-amyl) peroxide) CAS# 10508-09-5; LUPEROX P (t-butyl peroxy benzo ate) CAS# 614-45-9; LUPEROX TAP (t-amyl peroxy benzo ate) CAS# 4511-39-1; LUPEROX F (a,a’-bis(t-butylperoxy)-diisopropylbenzene) CAS# 25155-25-3; and LUPEROX TBEC (OO-t-butyl O-(2-ethylhexyl) monoperoxycarbonate) CAS# 34443-12-4. LUPEROX 101 is the preferred peroxide. The purpose of the peroxide is to function as a free-radical initiator by producing radical species for radical reactions, in particular, grafting reactions. The peroxide may decompose into at least one primary radical selected from the following radicals: (a) RCOO, wherein R is an alkyl; (b) RO*. wherein R is an alkyl; or c) ROC(O)O*, wherein R is an alkyl. In some embodiments, the reactive mixture comprises a combination of two or more peroxides.

[0035] The epoxy-functionalized polyolefin may be grafted in an extruder, including but not limited to, co-rotating intermeshing twin screw extruders, counter-rotating twin screw extruders, tangential twin screw extruders, Buss kneader extruders, planetary extruders, and single screw extruders. Further, features of interest are design specifications including the length / diameter ratio (L / D ratio) and mixing sections (screw design). Typically, with a single extruder, the maximum L / D ratio is about 60. For longer L / D ratios, two extruders are coupled. Screw designs include, but are not limited to, those comprising of mixing elements, such as kneading disc blocks, left handed screw elements, turbine mixing elements, gear mixing elements, and combinations made thereof.

[0036] In embodiments, the epoxide-functionalized polyolefin may be post-treated to remove unreacted epoxide-containing monomer and radical initiator.

[0037] Epoxide-Functionalized Polyolefin

[0038] In embodiments, the epoxide-functionalized polyolefin has a graft level of from 0.1 to 3.0 wt.%. In some embodiments, the epoxide-functionalized polyolefin may comprise a graft level of from 0.2 to 2.5 wt.% , from 0.3 to 2.0 wt.%, from 0.4 to 1.5 wt.%, from 0.5. to 1.0 wt.%, from 0.6 to 0.9 wt.%, or from 0.7 to 0.8 wt.%. All individual values and subranges from 0.1 to 3.0 wt.% are included herein and disclosed herein.

[0039] In embodiments, the epoxide-functionalized polyolefin has a melt index (E) from 1 dg / min to 16.0 dg / min, as measured according to ASTM-1238 Condition B (190 °C, 2.16 kg), v melt index (I2) from 2 dg / min to 15.0 dg / min, from 3 dg / min to 14.0 dg / min, from 4 dg / min to 13.0 dg / min, from 5 dg / min to 12.0 dg / min, from 6 dg / min to 11.0 dg / min, from 7 dg / min to 10.0 dg / min, or from 8 dg / min to 9.0 dg / min. All individual values and subranges from 1 dg / min to 16.0 dg / min are included herein and disclosed herein.

[0040] In embodiments, the epoxide-functionalized polyolefin has an extractable homopolymer content of greater than or equal to 0 wt.% and less than or equal to 0.60 wt.%, as determined by NMR spectroscopy. In embodiments, the epoxide-functionalized polyolefin has an extractable homopolymer content of greater than or equal to 0.01 wt.% and less than or equal to 0.55 wt.%, greater than or equal to 0.05 wt.% and less than or equal to 0.5 wt.%, greater than or equal to 0.1 wt.% and less than or equal to 0.50 wt.%, greater than or equal to 0.15 wt.% and less than or equal to 0.45 wt.%, greater than or equal to 0.20 wt.% and less than or equal to 0.40 wt.%, greater than or equal to 0.25 wt.% and less than or equal to 0.35 wt.%, or greater than or equal to 0.30 wt.% and less than or equal to 0.35 wt.%. All individual values and subranges from 0 wt.% to 0.60 wt.% are included herein and disclosed herein.

[0041] In embodiments, the epoxide-functionalized polyolefin has a grafting efficiency onto the ethylene-based polymer greater than or equal to 15% and less than or equal to 80%. In embodiments, the epoxide-functionalized polyolefin has a grafting efficiency onto the ethylenebased polymer greater than or equal to 20% and less than or equal to 75%, greater than or equalto 25% and less than or equal to 70%, greater than or equal to 30% and less than or equal to 65%, greater than or equal to 35% and less than or equal to 60%, greater than or equal to 40% and less than or equal to 55%, or greater than or equal to 45% and less than or equal to 50%. All individual values and subranges from 15% to 80% are included herein and disclosed herein.

[0042] In embodiments, the melt index of the epoxide-functionalized polyolefin may be changed by less than a factor of 2 after grafting relative to ungrafted ethylene-based polymer.

[0043] In embodiments, the epoxide-functionalized polyolefin may be molded into an article such as packaging materials, encapsulation materials for electronic components, bonding agents for automotive parts, and other applications.

[0044] Test Methods

[0045] The test methods as used herein include the following:

[0046] Melt index (MI)

[0047] Melt Index (h) was measured in accordance to ASTM D-1238 (method B) at 190 °C and 2.16 kg load.

[0048] Converted Monomer

[0049] Converted monomer is the wt.% non-volatile product of monomer grafting and is the sum of grafted monomer and homopolymer. After grafting the polymer was dried in a vacuum oven (<100 Torr) with a nitrogen bleed between 60-80 °C for 48 hours. The wt.% monomer is then determined by 1H NMR using a resonance diagnostic to the epoxide functionality as described in the NMR procedure.

[0050] Grafted Monomer

[0051] Grafted monomer is defined as the wt.% monomer that is bound to the polymer after grafting and subsequent precipitation into acetone. 1 g of polymer was dissolved in 15 mT oftoluene at 100-110 °C then precipitated into 100 mL of rapidly stirring acetone. The sample was collected by fdtration then dried under vacuum (-1 Torr) at 80 °C for 1 hour prior to NMR analysis. The wt% monomer is then determined by 1H NMR using a resonance diagnostic to the epoxide functionality as described in the NMR procedure.

[0052] Grafting Efficiency

[0053] Grafting efficiency was determined by normalizing the wt.% glycidyl crotonate determined byXH NMR with the wt.% fed into the formulation.

[0054] NMR

[0055] Spectra were acquired on a Varian 500 MHz spectrometer with cryoprobe. In a typical experiment, 15-30 mg of polymer was dissolved in 550 pT l,l,2,2-tetrachloroethane-d2 (Cambridge Isotope Taboratories) at 110 °C in a nitrogen flushed vial. The solution was transferred with a preheated glass pipet into a preheated 5 mm NMR tube, flushed with nitrogen, then capped. The spectra were acquired at 110 °C, with DI = 60s, and either 16 or 32 scans. ' l l NMR spectra were used to determine wt% grafted comonomer for both glycidyl crotonate (GC) and glycidyl methacrylate (GMA) grafted polymers. After thorough phasing and baselining, the residual solvent peak was referenced to 5.99 ppm. A description of the specific methods for each type of polymer are given below. The same procedure is used to determine wt.% grafted monomer after precipitation and wt.% converted monomer after vacuum drying

[0056] Polymers 1 and 2 grafted with GC. Two integral regions were used to estimate the polymer composition: aliphatic (1.8-0.8 ppm) and epoxide methine (1H, -3.25 ppm). The integral of the methine was set to 1 and the resulting integral of the aliphatic region was used to calculate the wt% GC:

[0057] wt% GC = 100

[0058] Polymers 1 and 2 grafted with GMA. Two integral regions were used to estimate the polymer composition: aliphatic (1.8-0.8 ppm) and epoxide methine (1H, -3.25 ppm). The integralof the methine was set to 1 and the resulting integral of the aliphatic region was used to calculate the wt% GMA.

[0059] wt% GMA = 100

[0060] Polymer 3 Grafted with GC. Polymer 3 is an E / BA copolymer. Initially 1H NMR was used to determine that the weight percent BA is 27%. For the grafted polymer, two integral regions were used to estimate the polymer composition: BA methylene (-CO2CH2-) (4.17 ppm) and epoxide methine He (1H, -3.25 ppm). The integral of the methine was set to 1 and the resulting integral of the aliphatic region was used to calculate the wt% GC.

[0061] wt% GC = 100

[0062] Polymer 3 Grafted with GMA. Polymer 3 is an E / BA copolymer. Initially 1H NMR was used to determine that the weight percent BA is 26%. For the grafted polymer, two integral regions were used to estimate the polymer composition: BA methylene (-CO2CH2-) (4.17 ppm) and epoxide methine (1H, -3.25 ppm). The integral of the methine was set to 1 and the resulting integral of the aliphatic region was used to calculate the wt% GC.

[0063] 100

[0064] Homopolymer

[0065] Weight percent homopolymer was determined using the following equation:Homopolymer (wt.%) = Converted monomer (wt.%) - Grafted monomer (wt%) (EQ 5)EXAMPLES

[0066] 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.

[0067] The materials used in this study are shown in Table 1.

[0068] Table 1 - Reagents

[0069] Synthesis of Glycidyl Crotonate

[0070] To prepare the glycidyl crotonate, 167 g of crotonic acid (1.94 mol) and 131.2 g of potassium carbonate (0.950 mol) were added to a 2 T beaker. Deionized water was gradually added with stirring and heating to 60 °C, allowing effervescence to dissipate. A homogeneous solution was achieved with the addition of 700 mT of water. The water was then evaporated under reduced pressure using toluene to form an azeotrope. Once dry, the solid was transferred to a fritted fdter and washed with 100 mT of absolute ethanol. The resulting white powder was transferred to a 1 T round-bottom flask, purged with nitrogen (N2), and heated to 100 °C for 4 hours, yielding 224 g of potassium crotonate. The material was used directly in the subsequent step without further purification or analysis.

[0071] Next, 111 g of potassium crotonate (0.895 mol) and 499 g of epichlorohydrin (5.40 mol) were combined in an oven-dried 1 T flask equipped with a reflux condenser and stir bar, and purged with nitrogen for 30 minutes. The mixture was heated to reflux with vigorous stirring for 48 hours. After cooling, the mixture was filtered, and the residual salt was washed with toluene.The combined filtrate was evaporated under reduced pressure to yield a viscous yellow oil. The reaction was repeated, and the materials from both runs were combined for further distillation. The combined fractions were distilled at 76 °C (22 mmHg), yielding 174 g of a clear liquid with a 69% yield.

[0072] Extrusion Procedure

[0073] To produce the Examples and Comparative Examples described below, each grafting reaction was performed on an 11 mm co-rotating, fully intermeshing, twin screw extruder (Thermofisher). The extrusion system also included a high-performance liquid chromatography (HPEC) pump for injecting a glycidyl crotonate and peroxide mixture, a devolatilization system for removing unreacted reagents and byproducts, a single-hole die (0.125-inch diameter), a water bath, and a strand pelletizer system. The extruder was equipped with 11 mm diameter twin screws and eight sections, yielding a total length-to-diameter ratio of 44. Each barrel section was independently controlled with electric heating and water cooling. The resin feed rate was 750 g / h, and the screw speed was maintained at 350 rpm. A vacuum of greater than 25 inches of mercury (Hg) was applied.

[0074] A Movacolor loss-in-weight feeder delivered resin pellets into the extruder hopper under a nitrogen purge in the first section of the extruder. The HPEC pump injected the glycidyl crotonate / peroxide mixture into the extruder at the fourth section. The devolatilization system, located at the eighth section, included a vacuum line-trap system with a knock-out pot to remove unreacted glycidyl crotonate and any byproducts. The polymer melt was extruded through the die, cooled in a water bath, and subsequently pelletized using a strand pelletizing system.

[0075] The compositions of the Examples and Comparative Examples are shown in Table 2, along with the graft level (glycidyl crotonate wt.%), graft efficiency (%), homopolymer content (wt.%), converted monomer (wt.%), and MI each determined according to the test methods described above.

[0076] Table 2: Inventive Examples

[0077] Table 3: Comparative Examples

[0078] The results shown in Tables 2 and 3 demonstrate the low grafting level and efficiency with higher amounts of homopolymer when GMA is used as the grafting monomer versus glycidyl crotonate. In other words, the grafting reaction of an epoxide group onto a polyolefin can be enhanced when using a glycidyl crotonate. The results in Table 2 and 3 further indicate the effect of various monomers. In particular, when the results for the Examples are compared with the Comparative Examples, it becomes clear that when glycidyl crotonate is used as the monomer, the graft efficiencies range up to 30% and the graft levels range up to 1.21 wt.%. However, when GMA is used, the graft efficiencies are consistently 20% or less and the graft levels are less than or equal to 0.61 wt.%. Further, the glycidyl crotonate-functionalized polyolefins show less amounts of homopolymer than polyolefins grafted with GMA.

[0079] The subject mater of the present disclosure has been described in detail and by reference to specific embodiments. It should be understood that any detailed description of a component or feature of an embodiment does not necessarily imply that the component or featureis essential to the particular embodiment or to any other embodiment. Further, it should be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

[0080] It is noted that one or more of the following claims utilize the term “wherein” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”

[0081] It should be understood that where a first component is described as “comprising” a second component, it is contemplated that, in embodiments, the first component “consists” or “consists essentially of’ that second component. It should further be understood that where a first component is described as “comprising” a second component, it is contemplated that, in embodiments, the first component comprises at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% that second component (where % can be weight % or molar %).

[0082] It is also noted that recitations herein of “at least one” component, element, etc., should not be used to create an inference that the alternative use of the articles “a” or “an” should be limited to a single component, element, etc.

Claims

CLAIMS1. An epoxide-functionalized polyolefin comprising ethylene-based polymer grafted with an epoxide-containing monomer having the following structure:wherein:R is a methyl, ethyl, propyl, or butyl group; n is from 1 to 8; and the ethylene-based polymer is the polymerized reaction product of ethylene and optionally at least one additional comonomer selected from C3-C12 alpha-olefins or polar comonomers.

2. The epoxide-functionalized polyolefin of claim 1, wherein the additional comonomer comprises C4-C8 alpha-olefins.

3. The epoxide-functionalized polyolefin of any preceding claim, wherein the additional comonomer comprises alkyl acrylates.

4. The epoxide-functionalized polyolefin of any preceding claim, wherein the epoxide- functionalized polyolefin has an epoxide-containing monomer graft level of from 0.1 wt.% to 3.0 wt.%.

5. The epoxide-functionalized polyolefin of any preceding claim, wherein the epoxide- functionalized polyolefin has a melt index (I2) from 1 dg / min to 16.0 dg / min.

6. The epoxide-functionalized polyolefin of any preceding claim, wherein the epoxide- containing monomer is glycidyl crotonate.

7. An article comprising the epoxide-functionalized polyolefin of any preceding claim.

8. A method of making the epoxide-functionalized polyolefin of any of claims 1 to 6, the method comprising: initiating a free radical grafting reaction between the ethylene-based polymer and the epoxide-containing monomer in the presence of a radical initiator to produce the ethylenebased polymer grafted with epoxide-containing monomer.

9. The method of claim 8, wherein the epoxide-functionalized polyolefin has an extractable homopolymer content of from 0 wt.% to 0.60 wt.%, as determined by NMR spectroscopy.

10. The method of claims 8 or 9, wherein the epoxide-containing monomer has a grafting efficiency onto the ethylene-based polymer of from 15% to 80%.

11. The method of any one of claims 7 to 10, wherein the radical initiator is a peroxide.

12. The method of any one of claims 7 to 11, wherein the melt index of the epoxide- functionalized polyolefin is changed by less than a factor of 2 after grafting in relation to the ethylene-based polymer.

13. The method of any one of claims 7 to 12, wherein the free radical grafting reaction is carried out in a melt phase at a temperature from 100° C to 300° C.

14. The method of any one of claims 7 to 13, wherein the epoxide-containing monomer is fed in an amount from 0.5 wt.% to 10 wt. % relative to the feed of the ethylene-based polymer, and the radical initiator is fed in an amount of from 0.075 wt.% to 1.0 wt. % relative to the feed of the ethylene-based polymer.

15. The method of any one of claims 7 to 14, further comprising post-treating the epoxide- functionalized polyolefin to remove unreacted epoxide-containing monomer and radical initiator.

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