BACKGROUND

[0001] Ethylene vinyl acetate (EVA) is widely used to produce foams with light weight and very high toughness, resilience, and compression set. EVA foams find application in demanding applications such as running shoe midsoles as well as automotive and construction applications such as interior padding, carpet underlay, gaskets, etc. The polymer architecture that is required for EVA shoe midsoles and other foam applications is a three dimension network, produced by crosslinking neighboring polymer molecules.

[0002] Covalently bonded polymer networks provide a balance of performance, properties, and durability. However, the same characteristics that make permanent networks excellent candidates in materials selection for high performance foams represent a difficult environmental challenge. Once formed, the material with these network structures do not melt, flow, or dissolve to enable the use of conventional reprocessing or recycling methods.

[0003] The industrial scrap produced during processing of permanent networks cannot be fully reintroduced to the manufacturing process as a secondary feedstock and only a small fraction of industrial waste from crosslinked polymers is ground and reintroduced as filler. Likewise, end-of-life parts produced from permanently crosslinked polymers have limited recycling options such as energy intensive grinding operations that generate only low value materials. As a result, a significant proportion of industrial scrap and end-of-life parts accumulates as environmental waste.

[0004] In addition to a significant environmental impact, the fact that covalent, crosslinked EVA foams cannot by reprocessed by melting represents a significant cost for manufacturers. The high amount of waste limits the utilization rate of primary materials and generates cost to handle waste.

[0005] There is a need for technology that enables re-processing of crosslinked polymers, especially crosslinked foam EVA. SUMMARY

[0006] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0007] In one aspect, embodiments disclosed herein relate to a polymer composition that includes a thermoplastic polymer; and a crosslinked recycled EVA scrap present as a dispersed phase within a matrix of the thermoplastic polymer.

[0008] In one aspect, embodiments disclosed herein relate to an article that includes a polymer composition that includes a thermoplastic polymer; and a crosslinked recycled EVA scrap present as a dispersed phase within a matrix of the thermoplastic polymer.

[0009] In another aspect, embodiments disclosed herein relate to a method of processing crosslinked recycled EVA scrap, that includes melt mixing a thermoplastic polyolefin with a crosslinked EVA to form the polymer composition that includes a thermoplastic polymer; and a crosslinked EVA present as a dispersed phase within a matrix of the thermoplastic polymer.

[0010] In yet another aspect, embodiments disclosed herein relate to a method that includes processing a polymer composition that includes a thermoplastic polymer; and a crosslinked recycled EVA scrap present as a dispersed phase within a matrix of the thermoplastic polymer, where the processing is by a process selected from the group consisting of extruding, compression molding, injection molding, foaming, and additive manufacturing.

[0011] In yet another aspect, embodiments disclosed herein relate to an expanded article comprising a polymer composition that includes a thermoplastic polymer, and a crosslinked recycled EVA scrap present as a dispersed phase within a matrix of the thermoplastic polymer.

[0012] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS [0013] Figures 1 -3 are graphs showing the shear rheology of a polymer composition in accordance with one or more embodiments of the present disclosure.

[0014] Figures 4 to 15B are scanning electron microscope (SEM) images taken from samples according to embodiments of the present application (magnifications varying from 20x to 2000x).

[0015] Figure 4 is a scanning electron microscope (SEM) image of Sample 34 taken at a 20x magnification.

[0016] Figure 5 is an SEM image of Sample 35 taken at a 20x magnification.

[0017] Figure 6 shows SEM images of Sample 34 taken at a 290x magnification.

[0018] Figure 7 shows SEM images of Sample 35 taken at a 290x magnification.

[0019] Figure 8 shows SEM images of Sample 34 taken at a 290x magnification.

[0020] Figure 9 shows SEM images of Sample 35 taken at a 290x magnification.

[0021] Figure 10 shows SEM images of Sample 34 taken at a 290x magnification.

[0022] Figure 11 shows SEM images of Sample 35 taken at a 290x magnification.

[0023] Figures 12A-12C show SEM images of Sample 34 taken at progressively higher magnifications of 290x, lOOOx and 2000x.

[0024] Figures 13A-13C show SEM images of Sample 34 taken at progressively higher magnifications of 290x, lOOOx and 2000x.

[0025] Figures 14A-14C show SEM images of Sample 35 taken at progressively higher magnifications of 290x, lOOOx and 2000x.

[0026] Figures 15A-15C show SEM images of Sample 35 taken at progressively higher magnifications of 290x, lOOOx and 2000x.

DETAILED DESCRIPTION

[0027] The present disclosure generally relates to a polymer composition and a method of preparation thereof. The polymer composition may include crosslinked recycled ethyl vinyl acetate (EVA) scrap dispersed therein. The crosslinked recycled EVA scrap may be included in polymer compositions of the present disclosure as an impact modifier. As such, inclusion of crosslinked recycled EVA scrap may provide a polymer composition that has an improved balance of stiffness and impact strength, as well as an enhanced environmental stress crack resistance (ESCR). A method of preparing a polymer composition of one or more embodiments may include melt mixing the recycled EVA scrap with a matrix polymer such that the EVA is present as a dispersed phase within the matrix polymer. Disclosed polymer compositions may be used to produce various articles having enhanced mechanical and rheological properties.

[0028] Polymer Composition

[0029] In one aspect, embodiments disclosed herein relate to a polymer composition. The polymer composition may include a matrix polymer and a crosslinked recycled EVA scrap. In one or more embodiments, the crosslinked recycled EVA scrap is present in the polymer composition as a dispersed phase within the matrix polymer.

[0030] The matrix polymer of one or more embodiments may be a thermoplastic polymer. A thermoplastic polymer refers to a polymer that has a crystalline structure that may soften when heated and harden when cooled. Any thermoplastic polymer known in the art may be a suitable matrix polymer. In one or more embodiments, the matrix polymer comprises one or more polyolefins. The polyolefins may be derived from a fossil-based source, bio-based source, and mixture thereof. Suitable polyolefins include, but are not limited to, polyethylene, polypropylene (including random and heterophasic copolymers), ethyl vinyl acetate, and combinations thereof. In embodiments in which the matrix polymer is polyethylene, the polyethylene may be high-density polyethylene (HD PE), low- density polyethylene (LDPE), or linear low-density polyethylene (LLDPE). Polyolefins used as the matrix polymer may be virgin, recycled from post-consumer or post-industrial sources.

[0031] In one or more embodiments, the polymer composition includes a matrix polymer in an amount ranging from 10 to 85 wt%, based on the total weight of the polymer composition. For example, the matrix polymer may be present in the polymer compositions in an amount ranging from a lower limit of one of 10, 20, 30, 40, and 50 wt%, to an upper limit of one of 45, 55, 65, 75, 85, and 90 wt% where any lower limit may be paired with any mathematically compatible upper limit. [0032] As described above, polymer compositions of one or more embodiments include crosslinked recycled EVA scrap. Suitable sources of recycled crosslinked EVA scrap include, but are not limited to, post-consumer EVA scrap, post-industrial EVA scrap, and EVA foam scrap, such as from shoe midsoles. In particular embodiments, the crosslinked recycled EVA is EVA foam scrap. In some embodiments, the large pieces of EVA scrap may be processed by grinding, milling, or other forms of chopping into small pieces, to provide small particles of crosslinked EVA scrap. Such small particles of crosslinked recycled EVA are melt- mixed with a thermoplastic polymer so that the small particles of crosslinked EVA become a dispersed phase within the matrix of thermoplastic polymer. The crosslinked recycled EVA scrap may be bio-based or fossil-based, or may comprise a mixture thereof. The crosslinked EVA scrap may also comprise further polymers, elastomers or a mixture thereof, including polyolefins like polyethylene or polypropylene and also polyolefin elastomers (POE).

[0033] In one or more embodiments, the crosslinked EVA scrap contains at least about 10 wt.% and up to about 90 wt.% of EVA, based on the total weight of the scrap. Preferably, the EVA scrap contains at least 30 wt.%, or at least 40 wt.% or at least 50 wt.% of EVA. Alternatively, the EVA scrap may also contain inorganic fillers in an amount up to 50 wt.%, based on the total weight of the scrap.

[0034] In the context of the present application, innorganic fillers may include, but are not limited to, carbon black, silica powder, calcium carbonate, talc, titanium dioxide, clay, polyhedral oligomeric silsesquioxane (POSS), metal oxide particles and nanoparticles, inorganic salt particles and nanoparticles, recycled EVA, and mixtures thereof.

[0035] In one or more embodiments, the EVA particles (and dispersed phase) have an average particle size ranging from 50 to 1000 microns. For example, the crosslinked EVA may have an average particle size ranging from a lower limit of one of 50, 100, 200, 300, 400, and 500 microns to an upper limit of one of 500, 600, 700, 800, 900, and 1000 microns, where any lower limit may be paired with any mathematically compatible upper limit. It may be understood that while the average particle size may fall within such range, this does not exclude particles falling outside the range, for example some particles with a size of less than 10 microns and some particles with a size greater than 1000 microns as the average particle size may still fall within the described range. Particle size may be determined a variety of tools that are used in the art to measure particle size, such as mechanical sieves according to ASTM D-1921 or laser diffraction, such as provided by a commercially available instrument (Laser Diffraction Particle Size Analysis by Malvern Panalytical).

[0036] In one or more embodiments, the polymer composition includes crosslinked recycled EVA scrap in an amount ranging from about 15 to 90 wt%, based on the total weight of the polymer composition. For example, crosslinked EVA scrap may be present in the polymer composition in an amount ranging from a lower limit of one of 15, 20, 25, 30, 35, and 40 wt% to an upper limit of one of 45, 50, 60, 70, 80, and 90 wt%, where any lower limit may be paired with any mathematically compatible upper limit. In particular embodiments, the polymer composition includes crosslinked EVA scrap in an amount of about 20 to about 60 wt%, based on the total weight of the polymer composition. Particularly, the polymer composition includes crosslinked EVA scrap in an amount of 30 to 60 wt%, based on the total weight of the polymer composition.

[0037] In one or more embodiments, the polymer composition may also optionally include an elastomeric impact modifier. As used herein, an elastomeric impact modifier may be an elastomeric polymer that acts as an impact modifier, i.e., improves the impact resistance, in one or more disclosed polymer composition. The elastomeric impact modified may be a copolymer, a terpolymer, or any combination of one or more elastomeric polymers. In one or more embodiments, the elastomeric polymer is an olefin-based copolymer. Suitable olefin-based copolymers may include a monomer and a comonomer independently selected from C2 to CIO olefins. In one or more embodiments, the monomer and comonomer are different. Exemplary copolymers that may be included in the polymer composition as an elastomeric impact modifier include, but are not limited to, ethylene-based copolymers such as ethylene/propylene copolymers, ethylene/butene copolymers, ethylene/octene copolymers, ethylene/hexene copolymers, ethylene/decene copolymers; and propylene-based copolymers such as propylene/butene copolymers, propylene/octene copolymers, propylene/hexene copolymers, and propylene/decene copolymers. In particular embodiments, the elastomeric impact modifier may be an ethylene/octene copolymer.

[0038] In one or more embodiments, the polymer composition includes an elastomeric impact modifier in an amount ranging from about 10 to 30 wt%, based on the total weight of the polymer composition. For example, the elastomeric impact modifier may be present in the polymer composition in an amount ranging from a lower limit of one of 10, 12, 15, 17, and 20 wt% to an upper limit of one of 20, 22, 25, 27, 30, 32, or 35 wt%, where any lower limit may be paired with any mathematically compatible upper limit.

[0039] In one or more embodiments, the polymer composition includes a functionalized polymeric agent. In the present disclosure, a functionalized polymeric agent refers to a polymer that includes one or more functional groups. The functionalized polymeric agent may be a compatibilizing agent. In some embodiments, the functionalized polymeric agent may be formulated such that the one or more functional groups are grafted onto a polymeric backbone. Suitable functional groups that may be included in the functionalized polymeric agent include, but are not limited to, amino silanes, silanes, acrylates, meta-acrylates, unsaturated alpha-beta acids, and combinations thereof. In particular embodiments, the functionalized polymeric agent is a maleic anhydride grafted polyolefin such as, for example, maleic anhydride grafted polypropylene (PP-g-MA).

[0040] In one or more embodiments, the polymer composition includes a functionalized polymeric agent in an amount ranging from about 1.0 to 5.0 wt%, based on the total weight of the polymer composition. For example, the functionalized polymeric agent may be present in the polymer composition in an amount ranging from a lower limit of one of 1.0, 1.5, 2.0, and 2.5 wt% to an upper limit of one of 3.0, 3.5, 4.0, 4.5, and 5.0 wt%, where any lower limit may be paired with any mathematically compatible upper limit.

[0041] Polymer Composition Properties

[0042] As described above, disclosed polymer compositions may have an improved balance of stiffness and impact strength. Accordingly, in one or more embodiments, polymer compositions may not display an increase in both properties, but rather, an increase in the balance between such properties. For example, a reference polymer composition formulated without crosslinked EVA, may have a high flexural modulus, e.g., about 1,450 mega pascals (MPa) for PE, and a low IZOD impact strength, e.g., about 33 joules per meter (J/m) for PE. In contrast, a polymer composition including PE as the matrix polymer and crosslinked EVA scrap in accordance with the present disclosure, may have a relatively lower flexural modulus, e.g., ranging from 700 to 1,300 MPa, and a higher IZOD impact strength, e.g., ranging from 200 to 600 J/m. Thus, the polymer composition in accordance with the present disclose has an improved balance between the two properties.

[0043] In one or more embodiments, polymer compositions have a sufficient flexural modulus. Polymer compositions including a polyethylene matrix polymer such as HDPE and LDPE may have a flexural modulus ranging from about 700 to about 1,300 MPa, as measured with a 1% Secant Modulus according to ASTM D790, method B. For example, polymer compositions of one or more embodiments have a flexural modulus ranging from a lower limit of one of 700, 750, 800, 850, and 900 MPa to an upper limit of one of 1,000, 1,100, 1,200, 1,250, and 1,300 MPa where any lower limit may be paired with any mathematically compatible upper limit.

[0044] In other embodiments, polymer compositions including a polypropylene matrix polymer have a flexural modulus ranging from about 500 to about 650 MPa, as measured with a 1% Secant Modulus according to ASTM D790, method A. For example, polymer compositions of one or more embodiments have a flexural modulus ranging from a lower limit of one of 500, 520, 550, 570, and 600 MPa to an upper limit of one of 600, 610, 620, 630, 640, and 650 MPa, where any lower limit may be paired with any mathematically compatible upper limit.

[0045] In one or more embodiments, polymer compositions have an improved IZOD impact strength compared to a reference polymer composition formed without crosslinked EVA. Polymer compositions including a polyethylene matrix polymer may have an IZOD impact strength ranging from about 200 to about 600 J/m, as measured according to ASTM D256. For example, polymer compositions of one or more embodiments have an IZOD impact strength ranging from a lower limit of one of 200, 250, 300, 350, and 400 J/m to an upper limit of one of 400, 450, 500, 550, and 600 J/m where any lower limit may be paired with any mathematically compatible upper limit.

[0046] In other embodiments, polymer compositions including a polypropylene matrix polymer have an IZOD impact strength ranging from about 35 to about 600 J/m, as measured according to ASTM D256. For example, polymer compositions of one or more embodiments have an IZOD impact strength ranging from a lower limit of one of 35, 40, 45, 50, 55, and 60 J/m to an upper limit of one of 100, 200, 300, 400, 500, and 600 J/m where any lower limit may be paired with any mathematically compatible upper limit.

[0047] Polymer compositions in accordance with the present disclosure may have properties other than impact strength and flexural modulus that are comparable to, or improved from, reference polymers formulated without EVA. Such properties include melting point, tensile modulus, break stress, elongation at break, and Shore A hardness. Tests to determine these properties may be carried out according to methods known in the art, such as ASTM methods.

[0048] In one or more embodiments, the polymer composition has substantially the same melting point as a reference polymer composition formed without crosslinked EVA. For example, polypropylene, as a reference polymer composition has a melting point ranging of about 144 to about 168°C, depending on the type of polymer such as homopolymer or random copolymer. Polypropylene including crosslinked EVA, as in polymer compositions of one or more embodiments, may have a melting point range of that is substantially the same or the same as a reference polymer (without the crosslinked EVA added thereto) as measured according to ASTM D3418.

[0049] In one or more embodiments, polymer compositions have a break stress ranging from about 15 to about 21 MPa, as measured according to ASTM D638 Specimen Type I. For example, in one or more embodiments, polymer compositions have a break stress ranging from a lower limit of one of 15, 16, 17, and 18 MPa to an upper limit of one of 18, 19, 20, and 21 MPa, where any lower limit may be paired with any mathematically compatible upper limit. [0050] In one or more embodiments, polymer compositions have an elongation at break ranging from about 20 to about 600% as measured according to ASTM D638 Specimen Type IV. For example, in one or more embodiments, polymer compositions have an elongation at break ranging from a lower limit of one of 20, 30, 50, 100, 150, and 200% to an upper limit of one of 200, 300, 400, 500, and 600%, where any lower limit may be paired with any mathematically compatible upper limit.

[0051] In one or more embodiments, polymer compositions have a tensile modulus, at a 1% secant, ranging from about 100 to about 2,250 MPa as measured according to ASTM D638 Specimen Type IV. For example, in one or more embodiments, polymer compositions have a tensile modulus ranging from a lower limit of one of 100, 200, 300, 400, 500, and 600 MPa to an upper limit of one of 1,000, 1,250, 1500, 1,750, 2,000, and 2,250 MPa, where any lower limit may be paired with any mathematically compatible upper limit.

[0052] In one or more embodiments, polymer compositions have a Shore A Hardness ranging from about 90 to 100 as measured according to ASTM D2240. For example, in one or more embodiments, polymer compositions have a Shore A Hardness ranging from a lower limit of one of 90, 91, 92, 93, 94, and 95 to an upper limit of one of 95, 96, 97, 98, 99, and 100, where any lower limit may be paired with any mathematically compatible upper limit.

[0053] In one or more embodiments, polymer compositions have a Rockwell Hardness ranging from about 20 to 100 HRC as measured according to ASTM D0785. For example, in one or more embodiments, polymer compositions have a Rockwell Hardness ranging from a lower limit of one of 20, 30, 40, 50, and 60 HRC to an upper limit of one of 75, 80, 85, 90, 95, and 100 HRC, where any lower limit may be paired with any mathematically compatible upper limit.

[0054] In one or more embodiments, polymer compositions have an environmental stress crack resistance (ESCR) ranging from about 200 hours to about 1,000 hours or higher, as measured according to ASTM DI 693. For example, the polymer composition may have an ESCR ranging from a lower limit of one of 200, 250, 300, 350, 400, 450, and 500 hours to an upper limit of one of 600, 700, 800, 900, and 1,000 hours, where any lower limit may be paired with any mathematically compatible upper limit. In particular embodiments, polymer compositions have an ESCT higher than 1,000.

[0055] Polymer compositions of one or more embodiments exhibit thermoplastic flow performance, as determined by small angle oscillatory shear rheology. Thus, polymer compositions may be used in a range of processes including melting and conveying, such as in extrusion and injection-molding. Oscillatory shear tests demonstrate that the at high shear rate, the complex viscosity of the inventive blends is similar to that of the matrix polymer. This rheological behavior indicates that the inventive blends may be processed using typical melt processing equipment.

[0056] Optional Additives

[0057] In one or more embodiments, the polymer compositions of the present disclosure may contain a number of other functional additives that modify various properties of the composition such as antioxidants, pigments, fillers, reinforcements, adhesion-promoting agents, biocides, whitening agents, nucleating agents, antistatics, anti-blocking agents, processing aids, flame-retardants, plasticizers, light stabilizers, and the like.

[0058] In one or more embodiments, fillers and/or nanofillers in accordance with the present disclosure may be incorporated into a polymer composition at a percent by weight (wt %) up to 70 wt %. solid filler. The filler may be an inorganic particle such as talc,CaCO3, glass fibers, marble dust, cement dust, clay, silica or glass, fumed silica, silicates, calcium silicate, silicic acid powder, glass microspheres, mica, metal oxide particles and nanoparticles, and the like. The filler may also be biobased such as nanocrystalline cellulose. The filler may be carbon based, such as graphene or carbon black.

[0059] In one or more embodiments, polymer compositions may contain a percent by weight of the total composition (wt %) of one or more additives ranging from a lower limit selected from one of 0.001 wt %, 0.01 wt %, 0.05 wt %, 0.5 wt %, and 1 wt %, to an upper limit selected from one of 1.5 wt %, 2 wt %, 5 wt %, and 7 wt %, where any lower limit can be used with any upper limit. [0060] In one or more embodiments, the polymer composition may be combined with one or more blowing agents and/or blowing accelerators.

[0061] Blowing accelerators (also known as kickers) enhance or initiate the action of a blowing agent by lower the associated activation temperature. For example, blowing accelerators may be used if the selected blowing agent reacts or decomposes at temperatures higher than 170 °C, such as 220 °C or more, where the surrounding polymer would be degraded if heated to the activation temperature. Blowing accelerators may include any suitable blowing accelerator capable of activating the selected blowing agent. In one or more embodiments, suitable blowing accelerators may include cadmium salts, cadmium-zinc salts, lead salts, lead-zinc salts, barium salts, barium-zinc (Ba-Zn) salts, zinc oxide, titanium dioxide, triethanolamine, diphenylamine, sulfonated aromatic acids and their salts, and the like. Polymer compositions in accordance with particular embodiments of the present disclosure may include zinc oxide as one of the one or more blowing accelerators.

[0062] Blowing agents produce expanded polymer compositions and foams. Blowing agents may include solid, liquid, or gaseous blowing agents. In embodiments utilizing solid blowing agents, blowing agents may be combined with a polymer composition as a powder or granulate.

[0063] Blowing agents in accordance with the present disclosure may include chemical blowing agents that decompose at polymer processing temperatures, releasing the blowing gases such as N2, CO, CO2, and the like. Examples of chemical blowing agents may include organic blowing agents, including hydrazines such as toluenesulfonyl hydrazine, hydrazides such as oxydibenzenesulfonyl hydrazide, diphenyl oxide-4,4'-disulfonic acid hydrazide, and the like, nitrates, azo compounds such as azodicarbonamide, cyanovaleric acid, azobis(isobutyronitrile), and N-nitroso compounds and other nitrogen-based materials, and other compounds known in the art.

[0064] Inorganic chemical blowing agents may include carbonates such as sodium hydrogen carbonate (sodium bicarbonate), sodium carbonate, potassium bicarbonate, potassium carbonate, ammonium carbonate, and the like, which may be used alone or combined with weak organic acids such as citric acid, lactic acid, or acetic acid.

[0065] In one or more embodiments of the present invention, lubricants may be added to the polymer composition to increase the overall rate of processing or to improve surface properties. Some examples of lubricants that may be added, but not limited to, are stearic acid and its Ca, Li, Ba, Al, Pb, etc., salts, natural waxes, mineral and vegetable oils.

[0066] Masterbatch Formulations

[0067] Polymer compositions in accordance with the present disclosure may be formulated as a “masterbatch” in which the polymer composition contains concentrations of crosslinked recycled EVA scrap that are high relative to the content in a final polymer blend for manufacture or use. For example, a masterbatch stock may be formulated for storage or transport and, when desired, be combined with additional polymer or other materials in order to produce a final polymer composition having concentration of constituent components that provides physical and chemical properties tailored to a selected end-use.

[0068] For example, the crosslinked recycled EVA scrap may be present in the final polymer composition (combined with a second quantity of matrix polymer or other materials) at a percent by weight of the polymer composition that ranges from 0.01 wt % to 95 wt %, where the lower limit may include any of 0.01, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 wt %, and the upper limit includes any of 50, 55, 60, 65, 70 75, 80, 85, 90, or 95 wt %, where any lower limit can be used in combination with any upper limit.

[0069] In one or more embodiments, the secondary polymer added to the masterbatch may include the thermoplastic polymer as previously described with respect to the polymer composition. In one or more embodiments, the thermoplastic polymer included in the masterbatch polymer composition is the same as the thermoplastic polymer blended with the polymer composition. In particular embodiments, the thermoplastic polymer is PP or HDPE or LDPE

[0070] Method of Preparing Polymer Compositions [0071] In another aspect, embodiments disclosed herein relate to a method of preparing a polymer composition including a matrix polymer and crosslinked recycled EVA scrap. The method may be carried out so as to provide a polymer composition in which the crosslinked EVA scrap is present as a dispersed phase within the matrix polymer.

[0072] As described above, in one or more embodiments, crosslinked recycled EVA scrap is collected from post-consumer and/or post-industrial sources and processed to provide a powder. Processing of the recycled EVA scrap may include grinding, milling, or otherwise chopping the larger EVA scrap pieces into particles. After such processing, the crosslinked EVA may have an average particle size ranging from 50 to 1000 microns. For example, processing of the EVA scrap into particles may provide EVA having an average particle size ranging from a lower limit of one of 50, 100, 200, 300, 400, and 500 microns to an upper limit of one of 500, 600, 700, 800, 900, and 1000 microns, where any lower limit may be paired with any mathematically compatible upper limit. In particular embodiments, the crosslinked EVA has an average particle diameter ranging from 50 to 500 microns.

[0073] In one or more embodiments, the crosslinked recycled EVA scrap and the matrix polymer are combined and then mixed at an elevated temperature. Herein, such process may be referred to as “melt mixing”. A suitable elevated temperature may be a temperature higher than the melting point of the matrix polymer so that the matrix polymer melts and the crosslinked EVA scrap particles are mixed therein, thereby forming a dispersed phase within the matrix polymer. It is specifically envisioned that the EVA particles may not fully melt. Any suitable elevated temperature may be used, provided that it does not exceed the degradation temperatures of the crosslinked EVA and the matrix polymer. Thus, the elevated temperature may be less than 250 °C. In one or more embodiments, the crosslinked EVA and the matrix polymer are melt mixed at an elevated temperature ranging from about 150 to about 230 °C. For example, suitable elevated temperatures may range from a lower limit of one of 150, 155, 160, 170, 180, and 190 °C to an upper limit of one of 200, 205, 210, 215, 220, 225, 230, and 250 °C, where any lower limit may be paired with any mathematically compatible upper limit. [0074] In one or more embodiments, melt mixing may be carried out by continuous or discontinuous extrusion. Methods may use single-, twin- or multi-screw extruders, which may be used at temperatures ranging from 150 °C to 160 °C in some embodiments and from 190 °C to 230 °C in some embodiments. In one or more embodiments, raw materials (crosslinked recycled EVA scrap and matrix polymer) are added to an extruder, simultaneously or sequentially, into the main or secondary feeder. Other embodiments may use a kneader, calender, or other internal mixers.

[0075] In one or more embodiments, the melt- mixing may include a plurality of meltmixing operations. For example, as mentioned above the polymer compositions described above may include formation of a masterbatch that is subsequently diluted to form a final polymer composition. This may allow for lower transportation costs associated with a masterbatch as well as tailoring the final polymer composition for the desired end product.

[0076] In one or more embodiments, after providing a polymer composition by melt mixing the crosslinked recycled EVA scrap and the matrix polymer, methods may also include pelletizing the polymer composition. The polymer composition may be pelletized to provide pellets, granules, or filaments, that may be used in the production of useful articles.

[0077] In one or more embodiments, the polymer compositions are used in extrusion, compression molding, injection molding, foaming, and additive manufacturing processes to provide articles. Exemplary articles that may be produced using disclosed polymer compositions include, but are not limited to, crates, barrels, buckets, and various automotive parts such as truck bed liners, construction materials, gaskets, seating, housewares, apparel, shoes, and appliances.

[0078] In one embodiment, expanded articles are made comprising the polymer composition according to the present invention. Such expanded articles include foams, and they may possess a density ranging from 0.01 to 0.6 g/cm ³ such as a density of 0.5 g/cm ³ or less, 0.45 g/cm ³ or less, 0.42 g/cm ³ or less, 0.41 g/cm ³ or less, 0.40 g/cm ³ or less, 0.38 g/cm ³ or less, 0.35 g/cm ³ or less, 0.32 g/cm ³ or less or 0.30 g/cm ³ or less in accordance ASTM D792. [0079] Expanded articles in accordance with one or more embodiments of the present disclosure may have an Asker C hardness as determined by JIS K7312 that ranges from a lower limit of any of 15, 20, 25 30, or 35 to an upper limit of 40, 45, 50, 55, or 60 Asker C, where any lower limit can be paired with any upper limit.

[0080] Expanded articles in accordance with one or more embodiments of the present disclosure may have a linear and width shrinkage of 3% or less, 2.8% or less, 2.5% or less, 2.3% or less, or 2.0% or less, as determined by ASTM D-955.

[0081] Expanded articles in accordance with one or more embodiments of the present disclosure may have a permanent compression deformation of lower than 65%, lower than 60%, lower than 50%, or lower than 45%, as determined by ASTM D395 using Method B at 50°C, 50% strain, for 6 hours).

[0082] Expanded articles in accordance with one or more embodiments of the present disclosure may have a wear of 3000mm ³ or less, 2500mm ³ or less, 2000mm ³ or less or 1500mm ³ or less, as determined by ISO 4649, measured with a load of 5 N.

[0083] Expanded articles in accordance with one or more embodiments of the present disclosure may have a reticulation rate of 50 or more, 60 or more, 70 or more, or 80 or more, as determined by ASTM D 2765.

[0084] Expanded articles in accordance with one or more embodiments of the present disclosure may have a hardness Shore A ranging from 25 to 40, and hardness Shore O ranging from 30 to 45, as determined by ASTM 1448.

[0085] Examples

[0086] Various grades of high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), and bio-based and fossil-based EVA (all supplied by Braskem) were used in combination with a recycled (and crosslinked) EVA scrap. Functionalized Polymeric Agent 1 (FPA1) was a 7 -MFR elastomer with the tradename TAFMER PN2070 obtained from Mitsui and Functionalized Polymeric Agent 2 (FPA2) was a 115-MFR MA-modified PP homopolymer with the tradename Polybond 3200 obtained from Addivant. Elastomer 1 was an ethylene-octene copolymer with the trade name Engage 8200 supplied by Dow. [0087] Post-industrial recycled EVA scrap was obtained from a commercial manufacturing facility that produces crosslinked EVA foam. The post-industrial recycled EVA scrap had a density of 0.210 g/cc, as measured by water displacement prior to grinding. The ground scrap had melting point of 80°C, as measured by differential scanning calorimetry (DSC) and a solids content of about 33 wt%, based on thermogravimetric analyses. The ground scrap had average particle size 200-300 microns, as measured by a Malvern laser diffraction particle size analyzer. The particle size distribution was also measured using sieves, which demonstrated that the median particle diameter in the distribution (known as the D50) is 205 microns. The detailed results are provided in Table 1 below.

Table 1

[0088] Mechanical properties of the following Samples were measured according to the following ASTM procedures. For all PE base resin samples (e.g., HDPE and LDPE), the flexural modulus was measured with a 1% Secant Modulus according to ASTM D790, method B. For all PP base resin samples, the flexural modulus was measured with a 1% Secant Modulus according to ASTM D790, method A. The IZOD impact strength was measured according to ASTM D256 for all samples.

[0089] Example 1 - Mechanical properties of the samples

[0090] Samples 1-2 (HDPE Base Resin)

[0091] In Samples 1-2, HDPE 1, a 2-melt flow polymer with tradename GE7252XP (HDPE 1), was melt/mixed via extrusion with two different concentrations of ground, post- industrial EVA scrap. Extrusion was conducted in a 21 mm Theysson twin screw extruder using a basic mixing screw. The HDPE base resin pellets were fed into the feed throat of the extruder using a first feeder. Ground EVA scrap was metered into the extruder feed throat using a second feeder. Barrel temperatures were set with a decreasing temperature profile (227 -> 216°C) Melt temperature was monitored to ensure that T _me it < 250°C to avoid EVA degradation. The screw speed was 270-175 rpm. The throughput rate was 6.8 kg per hour.

[0092] The extrudate mixtures were cooled in a water bath and collected as pellets, then molded according to ASTM methods to produce test specimen bars. The bars were tested by ASTM procedures listed above to measure mechanical properties. The mechanical properties in Table 4 below demonstrate that the inventive blends containing ground EVA scrap have significantly higher IZOD impact strength than an unfilled HDPE control (Comparative Example 1).

[0093] Samples 3-8 (PP Base Resin)

[0094] In Samples 3-8, PP, a 4-melt flow polymer with tradename D036W6, was melt/mixed with ground, post-industrial EVA scrap using the same extrusion conditions as Samples 1-2, but with higher barrel temperatures, shown in Table 3. Some of Samples 3-8 include FPA1 or FPA2 as compatibilizing agents. These samples demonstrate that the addition of EVA scrap provides a modest increase in IZOD impact strength at high scrap loading, as shown in Table 4.

[0095] Samples 9-12 (PP Base Resin)

[0096] In Samples 9-12, PP was melt/mixed with varying amounts of Elastomer 1 and ground post-industrial EVA scrap using the same extrusion conditions Samples 3-8. The PP pellets and Elastomer 1 were dry-blended and then fed to the extruder from a first feeder. The ground EVA scrap was fed into the feed throat of the extruder from a second feeder. The conditions for extrusion of Samples 9-12 are shown in Table 3.

[0097] As shown in Table 3, these samples demonstrate that the addition of EVA scrap along with elastomer to PP provides higher impact strength relative to Comparative Example 2, i.e., PP without filler.

[0098] Samples 13-14 (EVA Base Resin) [0099] In Samples 13-14, EVA was melt/mixed with ground, post-industrial EVA scrap using the extrusion conditions in Table 3. The EVA pellets were fed to the extruder from a first feeder. The ground EVA scrap was fed into the feed throat of the extruder from a second feeder. The mechanical properties of Samples 13-14 are shown in Table 4.

[00100] The composition of each of Samples 1-14 and Comparative Samples 1-2 are shown in Table 2, below.

Table 2. Composition of Samples 1-14 and Comparative Samples 1-2. [00101] The extrusion conditions for each of Sample 1-14 and Comparative Samples 1-2 are shown in Table 3, below.

[00102] Table 3. Extrusion Conditions for Examples and Comparative Examples.

[00103] The mechanical properties of each of Samples 1-14 and Comparative Samples 1-2 are shown in Table 4, below.

Table 4. Mechanical Properties of Samples 1-14 and Comparative Samples 1-2.

[00104] Samples 15-24

[00105] The following samples illustrate the advantages of the inventive composition in providing a balance of impact performance and stiffness in a range of polymer compositions include post-consumer recycled (PCR) polyethylene and polypropylene as a matrix polymer.

[00106] PCR-HDPE (BR.3OO3.S) and PCR-PP (BR.3OO3.I) were collected from a plastics recycler. PCR-PE has a melt flow index of 0.28 as measured at 190C (2.16 kg) and a flexural modulus of 1260 MPa. HDPE 2, grade GE7257, was a bimodal high density polyethylene grade, sold commercially by Braskem for the manufacturing of caps and closures. It had MFI=2 (190°C/ 2.16 kg). HDPE 3, grade GF4950, was a blow-molding grade sold by Braskem. It had MFI=0.34 (190C/ 2.16 kg) and MFI=28 (190°C/ 21.6 kg). PP 1 was a 47-MFR, heterophasic injection molding impact copolymer, sold by Braskem.

[00107] In the preparation of Samples 15-24, HDPE or PP pellets were melt mixed with ground, post-industrial EVA scrap in a 20 mm twin screw extruder using the formulations and extrusion conditions in Table 5, below.

[00108] Sample 25 was prepared with the initial HDPE (HDPE 1) as a matrix polymer and contained a high concentration (70 wt%) ground EVA scrap to generate a masterbatch. Sample 25 was then used in a further extrusion step to demonstrate that the inventive blends can be diluted to generate other compounds in downstream processes.

Table 5. Composition and Extrusion Conditions for Samples 15-25 and Comparative Sample

[00109] The mechanical properties shown in Table 6, below, demonstrate that the inventive blends containing HDPE plus ground EVA scrap (Samples 15-20) have lower stiffness, as indicated by flexural modulus, and significantly higher Izod impact strength than the comparative HDPE samples (Comparative Sample 1). The HDPE virgin resin and PCR-HDPE have significantly higher ESCR, measured according to ASTM D1693 than the unfilled comparative HDPE.

[00110] The inventive blends containing PP impact copolymer plus ground EVA scrap (Samples 21-23) had slightly higher Izod impact strength and lower stiffness than the PP comparative Sample (Comparative Sample 3). [00111] The PCR-PP blends containing high crystalline PP virgin resin plus EVA scrap (Sample 24) had higher flexural modulus and higher tensile strength than the comparative PCR-PP (Comparative Sample 3), and the inventive sample contained 60 wt% PCR-PP.

[00112] Comparative Sample 4 was PCR-HDPE without EVA, Comparative Sample 5 was PPI without EVA. Comparative Sample 6 is HDPE 2 without EVA, and Comparative Sample 7 is HDPE 3 without EVA.

Table 6. Mechanical Properties of Samples 15-25 and Comparative Samples 3-6.

[00113] Samples 26-33 [00114] Samples 26 to 33 were prepared to demonstrate the use of low-density polyethylene (LDPE) and post-consumer recycled (PCR) linear low-density polyethylene (LLDPE).

[00115] The LDPE was sold by Braskem with the tradename IP2418 and had a density of 0.919 g/cm ² , melt flow index (MFI) of 24 g/lOmin (190°C /2.16kg), and MFI=56.34 (190°C/ 21.6kg).

[00116] An HDPE sample (HDPE 4) was sold by Braskem with the tradename IG58, with a density of density 0.956 g/cm ³ , and a narrow molecular weight distribution, having a high melt flow rate (50g/10min), associating good stiffness and impact strength.

[00117] The post-consumer recycled LLDPE (PCR-LLDPE) was obtained from postconsumer stretch films. It contained 100% recycled material and had a density=0.921 g/cm2, MFI=2.4 g/lOmin (190°C/2.16 kg), and MFI=56.34 (190°C/21.6 kg.).

[00118] Extrusion was conducted using a SK26 G7730 26 mm twin-screw extruder. The micronized EVA scrap and polyethylene pellets were manually pre-mixed and fed to the feed throat. The screw rotation was maintained at 200 rpm, the throughput was 10-12 kilograms per hour, and the barrel set temperatures were: 130 / 180 / 190 / 200 / 200 (degassing 1) / 210 / 220 / 220 / 220 (degassing 2) / 220 / 225 (matrix)

[00119] In two of the samples (Sample 29 and Sample 30) the pellets were fed through a first feeder and the ground EVA scrap was fed to the extruder feed throat from a second feeder (indicated by 2F in the Formulation) to demonstrate an alternative feeding and mixing strategies that can be used to add the components of the inventive blends to the melt/mixing process.

[00120] The extrudate mixtures were cooled in a water bath and collected as pellets, then molded according to ASTM methods to produce test specimen bars. The bars were tested by ASTM procedures to measure mechanical properties.

[00121] The mechanical properties reported in Table 7 demonstrate that a wide range of stiffness and impact properties can be achieved by adjusting the amount of EVA scrap and the properties of the base resin. Blends containing up to 80 wt% scrap provided useful impact and stiffness results.

Table 7. Formulations and Mechanical Properties of Samples 26-33 and Comp. Sample 8.

[00122] Example 2 - Shear Rheology

[00123] Small angle oscillatory shear (SAGS) rheology was used to test the thermorheological behavior of the inventive blends. Sample 15, containing a low concentration (15 wt%) of scrap, Sample 25, containing a high concentration (70 wt%) of scrap, and Comparative Sample 1 were tested.

[00124] Viscosity was measured on an ARES G2 rotational rheometer manufactured by TA Instruments. Parallel plate geometry was used. Oscillation frequency was varied from 0.01 to 1000 rad/sec while temperature was held at 190°C.

[00125] Figures 1-3 show graphs related to the shear rheology of Samples 15 and 25 and Comparative Sample 1. The complex viscosity results shown in Figures 1-3 demonstrate that the inventive blends exhibit thermoplastic flow performance, suggesting that these materials can be used in a range of conventional processes that require melting and conveying, such as extrusion and injection-molding. Figure 1 shows that the inventive blends exhibited shear thinning at high shear rates. At shear rates greater than 100 rad/sec, the complex modulus of the blend containing 15 wt% scrap (Sample 15) was nearly identical to that of the HDPE sample that contained no filler (Comparative Sample 1) The complex modulus of the inventive blend master batch (Sample 25), which contained 70 wt% scrap, was less than 40% higher than that of the comparative HDPE at shear rates greater than 500 rad/sec.

[00126] Example 3 - foam application

[00127] Samples 34 and 35 were prepared to demonstrate the efficiency of the inventive compositions in providing foams to be used as plaques and footwear. Sample 34 comprises EVA crosslinked scraps and LDPE, while Sample 35 comprises EVA crosslinked scraps, green EVA and fossil-based EVA, as shown in Table 8.

[00128] The LDPE was sold by Braskem with the tradename IP2418 and had a density of 0.919 g/cm ² , melt flow index (MFI) of 24 g/lOmin (190°C /2.16kg), and MFI=56.34 (190°C/ 21.6kg).

[00129] The green EVA was sold by Braskem with the tradename SVT2180 and had a density of 0.940 g/cm ² (ASTM D 1505 / D 792), melt flow index (MFI) of 2.1 (190°C/2.16kg - ASTM D 1238) and vinyl-acetate content of 19% (ASTM-D-5594-98).

[00130] The fossil-based EVA was sold by Braskem with the tradename HM150 and had a density of 0.940 g/cm ² (ASTM D 1505 / D 792), melt flow index (MFI) of 150 g/lOmin (190°C /2.16kg) and vinyl-acetate content of 20% (ASTM-D-5594-98).

[00131] Extrusion was conducted using a twin-screw extruder. The micronized EVA scrap and polyethylene pellets were automatically mixed in a funnel before being fed to the feed throat. The screw rotation was maintained at 200 rpm, the throughput was 100-150 kilograms per hour, and the barrel set temperatures were: 130 / 180 / 190 / 200 / 200 (degassing 1) / 210 / 220 / 220 / 220 (degassing 2) / 220 / 225 (matrix).

Table 8: Formulations and Mechanical Properties of Samples 34 and 35.

[00132] SEM analysis

[00133] Phenom ProX /Thermo sFisher scanning electron microscope was used to compare the morphology of samples 34 and 35. The samples were cut in a half with a steel razor to expose the inside of the samples and they were fixed at the stub with carbon tape. Images of 10 (ten) different regions of each sample were captured at 290X magnification, in order to visualize a good sampling. And images were also captured at higher magnifications (lOOOx and 2000x) in order to assess whether there were visible points on the matrix that could suggest the presence of micronized EVA.

[00134] From Figures 6-11, it can be concluded that sample 35 (with EVA scrap, EVA green, and EVA fossil) shows cell size slightly larger than the sample 34. However, according to Figures 12-15, it can be noted that there is no difference in structures of samples 34 and 35; so, the micronized EVA (EVA scrap) is well dispersed in the polymer matrix, being compatible therewith. Different structures that could indicated the presence of micronized EVA not dispersed in the EVA matrix were not found, what would result in undesirable properties for the material.

[00135] What is further noted in the images is the presence of fillers (Figs. 12-15B). The structure of the cells with white particles indicates a high amount of fillers in the material. This is corroborated by the composition of the EVA scrap used in the samples of the present application. The EVA scrap has a high amount of filler (calcium carbonate) due to its original application (mainly plaques or insoles), which is not compatible with the polymeric matrix. [00136] Foam production

[00137] Samples 34 and 35 were mixed with azodicarbonamide as blowing agent, peroxide as cross-linking agent, stearin as release agent (lubricant), calcium carbonate as filler to produce foams.

[00138] All the items were mixed in a calender machine until achieve homogeneity. Then the mixture was added in a mold which was then submitted to heat and pressure in a equipment called compression molding machine. The machine conditions were 180°C and 40 ton for 7 minutes. After this, the mold was opened and the foam was formed.

[00139] The physical and mechanical properties of the foams were measured, as it is shown in table 9. The methodology of the measurements was the following: abrasion according to ISO 4649, wear according to ISO 4649, density according to ASTM D792, permanent compression deformation (PCD) according to ASTM D- 395, Reticulation Rate (RR) according to ASTM D 2765, Hardness Shore A and Hardness Shore O according to ASTM 1448, Linear and Width Shrinkage according to ASTM D-955.

Table 9. Physical and mechanical properties of the foams produced from samples 34 and 35.

[00140] It can be seen that the inventive compositions represented by samples 34 and 35 are suitable for foams. The obtained foams have good physical and mechanical properties and they meet requirements for application in plaques and footwear, since they have good resistance during abrasion and wear test and also achieved good values in hardness and shrinkage tests.

[00141] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.