Foams made with recycled material

Abstract

The present disclosure provides embodiments of a foam formed from a composition that includes from 25 pph to 55 pph, based on the composition, of ethylene vinyl acetate copolymer (EVA), wherein the EVA has a melt index of at least 15 dg / min; from 5 pph to 15 pph, based on the composition, of a polyolefin elastomer, an olefin block copolymer, or combinations of these; from 2 pph to 10 pph, based on the composition, of a coupling agent, wherein the coupling agent comprises ethylene-based polymer; and from at least 40 pph to 70 pph, based on the composition, of recycled material.

Description

FOAMS MADE WITH RECYCLED MATERIALCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 677,145 filed July 30, 2024, the contents of which are incorporated in their entirety herein.TECHNICAL FIELD

[0002] The present disclosure generally relates to a composition for foams, foams manufactured therefrom and to articles comprising the same.BACKGROUND

[0003] Recycling in the footwear industry, particularly the incorporation of post-industrial recycled (PIR) or post-consumer recycled (PCR) materials, is an important strategy for sustainability and waste reduction. However, integrating recycled materials into new products presents several challenges, especially when the percentage of recycled content exceeds 20 wt.%. At higher levels, the recycled material can negatively impact the physical properties and processability of the final product. This is due to issues such as the formation of a non-cohesive and non-homogeneous dough, leading to difficulties in handling and processing and also resulting in foam with structural defects and diminished performance properties. As such, improved foams with greater than 20% recycled material are desired.SUMMARY

[0004] Embodiments of the present disclosure meet this need for foams with greater than 20 % of recycled material by utilizing a base resin including an ethylene vinyl acetate copolymer (EVA) having a melt flow index of greater than or equal to 15 dg / min. This higher flow index counteracts the reduction in flow caused by the high amount of recycled material, thereby facilitating better processing and handling of the dough while maintaining acceptable performance properties in the final foam product.

[0005] 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.

[0006] 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

[0007] 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.

[0008] Definitions

[0009] As used herein, the term “composition” and like terms mean a mixture of two or more materials, such as a polymer which is blended with other polymers or which contains additive, fillers, or the like. Included in compositions are pre-reaction, reaction, and post-reaction mixtures, the latter of which will include reaction products and by-products as well as unreacted components of the reaction mixture and decomposition products, if any, formed from the one or more components of the pre-reaction or reaction mixture.

[0010] “Polymer” means a compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term homopolymer, usually employed to refer to polymers prepared from only one type of monomer, and the term copolymer as defined below. It also embraces all forms of copolymers, e.g., random, block, and the like. The terms “ethylene / alpha-olefin polymer” and “propylene / alpha-olefin polymer” are indicative of copolymers as described below. It is noted that although a polymer is often referred to as being “made of’ monomers, “based on” a specified monomer or monomer type, “containing” a specified monomer content, or the like, this obviously understood to be referring to the polymerized remnant of the specified monomer and not to the unpolymerized species.

[0011] “Polyolefin,” “polyolefin polymer,” “polyolefin resin,” and like terms mean a polymer produced from a simple olefin (also called an alkene with the general formula Cd bn) as a monomer. Polyethylene is produced by polymerizing ethylene with or without one or more comonomers, polypropylene by polymerizing propylene with or without one or more comonomers, and the like. Thus, polyolefins include copolymers such as ethylene-alpha-olefin copolymers, propylene-alpha-olefin copolymers, and the like.

[0012] “Foam” and like terms mean a substance that is formed by trapping many gas bubbles in a liquid or solid.

[0013] “Recycled material” refers to post-industrial recycled material (PIR), post-consumer recycled material (PCR), or both. Both PIR and PCR refer to material recycled from cross-linked and foamed polyolefin. Recycled polymers are defined in ISO 14021 7.8.1.1.

[0014] “Post-industrial recycled material (PIR)” refers to material separated from the waste stream during the manufacturing process as defined in ISO 14021 :2016.

[0015] The term “post-consumer recycled material” (or “PCR”) as used herein, refers to materials previously used in a consumer application and is further defined in ISO 14021 :2016.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] Disclosed herein is a foam formed from a composition containing 40 pph to 70 pph of recycled material, based on the weight of the composition. The composition includes ethylene vinyl acetate copolymer with a melt index of at least 15 dg / min. The composition also includes a polyolefin elastomer, an olefin block copolymer, or combinations of these. The composition also contains a coupling agent, wherein the coupling agent is at least an ethylene-based polymer.

[0020] EVA

[0021] In an embodiment, the foamable composition contains ethylene vinyl acetate (EVA) copolymer in an amount from 25 pph to 55 pph. The ethylene vinyl acetate copolymer may have a melt index of at least 15 grams per 10 min (g / lOmin) as measured per ASTM D 1238.

[0022] The EVA copolymer may be present in the formable composition in amount greater than or equal to 25 pph and less than or equal to 55 pph, greater than or equal to 25 pph and less than or equal to 50 pph, greater than or equal to 25 pph and less than or equal to 45 pph, greater than or equal to 25 pph and less than or equal to 30 pph, greater than or equal to 30 pph and less than 55 pph, greater than 30 pph and less than 50 pph, greater than 30 pph and less than 45 pph, greater than 30 pph and less than 40 pph, greater than 30 pph and less than 35 pph, greater than or equal to 35 pph and less than or equal to 55 pph, greater than or equal to 35 pph and less than or equal to 50 pph, greater than or equal to 35 pph and less than or equal to 45 pph, greater than orequal to 35 pph and less than or equal to 40 pph, greater than or equal to 40 pph and less than or equal to 55 pph, greater than or equal to 40 pph and less than or equal to 50 pph, greater than or equal to 40 pph and less than or equal to 45 pph, greater than or equal to 45 pph and less than or equal to 55 pph, greater than or equal to 45 pph and less than or equal to 50 pph, or even greater than or equal to 50 pph, and less than or equal to 55 pph, and any and all sub ranges between the above ranges.

[0023] The EVA copolymer may have a melt index of at least 15 g / lOmin, at least 16 g / lOmin, at least 17 g / lOmin, at least 18 g / lOmin, at least 19 g / lOmin, or even at least 20 g / lOmin. Without being limited by theory, utilizing an EVA having a higher melt index of at least 15 g / lOmin as a base resin helps counteract the reduction in flow caused by the high amount of recycled material, thereby facilitating better processing and handling of the dough while maintaining acceptable performance properties in the final foam product.

[0024] Olefin

[0025] In an exemplary embodiment, the foamable composition may contain a polyolefin elastomer, an olefin block copolymer (OBC), or a combination of these. The polyolefin elastomer can be a copolymer that comprises ethylene and an a-olefin. The polyolefin elastomer can be homogeneously or heterogeneously branched. Without being bound by theory, polyolefin elastomer, an olefin block copolymer (OBC), or a combination produce various properties in the foam such as rebound and reduced shrinkage.

[0026] In embodiments, the polyolefin elastomer, olefin block copolymer, or both, may have a melt index of at least at least 5 g / lOmin, 6 g / lOmin, 7 g / lOmin, 8 g / lOmin, 9 g / lOmin, 10 g / lOmin, 11 g / lOmin, 12 g / lOmin, 13 g / lOmin, 14 g / lOmin. 15 g / lOmin, at least 16 g / lOmin, at least 17 g / lOmin, at least 18 g / lOmin, at least 19 g / lOmin, 20 g / lOmin, 21 g / lOmin, 22 g / lOmin, 23 g / lOmin, 24 g / lOmin, 25 g / lOmin, 26 g / lOmin, 27 g / lOmin, 28 g / lOmin, 29 g / lOmin, 30 g / lOmin, 31 g / lOmin, 32 g / lOmin, 33 g / lOmin, 34 g / lOmin, 35 g / lOmin, 36 g / lOmin, 37 g / lOmin, 38 g / lOmin, 39 g / lOmin, or even at least 40 g / lOmin.

[0027] In an embodiment, the foamable composition contains a polyolefin elastomer, an olefin block copolymer (OBC), or a combination of these, in an amount from 5 pph to 15 pph. Theelastomer or OBC may be present in the formable composition in amount greater than or equal to 5 pph and less than or equal to 15 pph, greater than or equal to 5 pph and less than or equal to 10 pph, or even greater than or equal to 10 pph and less than or equal to 15 pph, and any and all sub ranges between the above ranges.

[0028] Copolymers comprising ethylene and an a-olefin are also known as ethylene / a-olefin copolymers. The term “ethylene / a-olefin copolymer” generally refers to polymers comprising ethylene and an a-olefin having 3 or more carbon atoms. Preferably, ethylene comprises the majority mole fraction of the whole polymer, i.e., ethylene comprises at least 50 mole percent of the whole polymer. More preferably ethylene comprises at least 60 mole percent, at least 70 mole percent, or at least 80 mole percent, with the substantial remainder of the whole polymer comprising at least one other comonomer that is preferably an a-olefin having 3 or more carbon atoms. For many ethylene / a-olefin copolymers, the preferred composition comprises an ethylene content greater than 80 mole percent of the whole polymer and an octene content of from 10 to 20, preferably from 15 to 20 mole percent of the whole polymer. In some embodiments, the ethylene / a-olefin copolymers do not include those produced in low yields or in a minor amount or as a by-product of a chemical process. While the ethylene / a-olefin copolymers can be blended with one or more polymers, the as-produced ethylene / a-olefin copolymers are substantially pure and often comprise a major component of the reaction product of a polymerization process.

[0029] The ethylene / a-olefin copolymers comprise ethylene and one or more copolymerizable a- olefin comonomers in polymerized form, characterized by multiple blocks or segments of two or more polymerized monomer units differing in chemical or physical properties. That is, the ethylene / a-olefin copolymers are block copolymers, preferably multi-block copolymers or copolymers. The terms “copolymer” and copolymer” are used interchangeably herein. In some embodiments, the multi-block copolymer can be represented by the following formula: (AB)nwhere 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 or segment and “B” represents a soft block or segment. Preferably, A's and B's are linked in a substantially linear fashion, as opposed to a substantially branched or substantially star-shaped fashion. In other embodiments, A blocks and B blocks are randomly distributed along the polymer chain.

[0030] In an embodiment, the ethylene / a-olefin copolymers used in embodiments (also referred to as “copolymer” or “polymer”) comprise ethylene and one or more copolymerizable a-olefm comonomers in polymerized form, characterized by multiple blocks or segments of two or more polymerized monomer units differing in chemical or physical properties (block copolymer), preferably a multi-block copolymer. The ethylene / a-olefin copolymers are characterized by one or more of the aspects described as follows.

[0031] The process of making the polymers has been disclosed in the following patent applications: U.S. Provisional Application No. 60 / 553,906, filed Mar. 17, 2004; U.S. Provisional Application No. 60 / 662,937, filed Mar. 17, 2005; U.S. Provisional Application No. 60 / 662,939, filed Mar. 17, 2005; U.S. Provisional Application No. 60 / 5662938, filed Mar. 17, 2005; PCT Application No. PCT / US2005 / 008916, filed Mar. 17, 2005; PCT Application No. PCT / US2005 / 008915, filed Mar. 17, 2005; and PCT Application No. PCT / US2005 / 008917, filed Mar. 17, 2005, all of which are incorporated by reference herein in their entirety.

[0032] The ethylene a-olefm copolymers used in some embodiments are preferably copolymers of ethylene with at least one C3-C20 a-olefm. Copolymers of ethylene and a C3-C20 a-olefm are especially preferred. The copolymers may further comprise C4-C18 diolefin and / or alkenylbenzene. Suitable unsaturated comonomers useful for polymerizing with ethylene include, for example, ethylenically unsaturated monomers, conjugated or nonconjugated dienes, polyenes, alkenylbenzenes, and the like. Examples of such comonomers include C3-C20 a-olefins such as propylene, isobutylene, 1 -butene, 1 -hexene, 1 -pentene, 4-methyl-l -pentene, 1 -heptene, 1 -octene, 1 -nonene, 1 -decene, and the like. 1 -Butene and 1 -octene are especially preferred. Other suitable monomers include styrene, halo- or alkyl-substituted styrenes, vinylbenzocyclobutane, 1,4- hexadiene, 1,7-octadiene, and naphthenics (e.g., cyclopentene, cyclohexene and cyclooctene).

[0033] While ethylene / a-olefin copolymers are preferred polymers, other ethylene / olefin polymers may also be used. Olefins as used herein refer to a family of unsaturated hydrocarbonbased compounds with at least one carbon-carbon double bond. Depending on the selection of catalysts, any olefin may be used in embodiments of the invention. Preferably, suitable olefins are C3-C20 aliphatic and aromatic compounds containing vinylic unsaturation, as well as cyclic compounds, such as cyclobutene, cyclopentene, dicyclopentadiene, and norbornene, including butnot limited to, norbornene substituted in the 5 and 6 position with C1-C20 hydrocarbyl or cyclohydrocarbyl groups. Also included are mixtures of such olefins as well as mixtures of such olefins with C4-C40 diolefin compounds.

[0034] Examples of olefin monomers include, but are not limited to propylene, isobutylene, 1- butene, 1 -pentene, 1 -hexene, 1 -heptene, 1 -octene, 1 -nonene, 1 -decene, and 1 -dodecene, 1- tetradecene, 1 -hexadecene, 1 -octadecene, 1-eicosene, 3-methyl-l -butene, 3 -methyl- 1 -pentene, 4- methyl-1 -pentene, 4,6-dimethyl-l -heptene, 4-vinylcyclohexene, vinylcyclohexane, norbornadiene, ethylidene norbornene, cyclopentene, cyclohexene, dicyclopentadiene, cyclooctene, C4-C40 dienes, including but not limited to 1,3 -butadiene, 1,3 -pentadiene, 1,4- hexadiene, 1,5 -hexadiene, 1,7-octadiene, 1,9-decadiene, other C4-C40 a-olefins, and the like. In certain embodiments, the a-olefin is propylene, 1 -butene, 1 -pentene, 1 -hexene, 1 -octene or a combination thereof. Although any hydrocarbon containing a vinyl group potentially may be used in embodiments of the invention, practical issues such as monomer availability, cost, and the ability to conveniently remove unreacted monomer from the resulting polymer may become more problematic as the molecular weight of the monomer becomes too high.

[0035] The polymerization processes described herein are well suited for the production of olefin polymers comprising monovinylidene aromatic monomers including styrene, o-methyl styrene, p- methyl styrene, t-butylstyrene, and the like. In particular, copolymers comprising ethylene and styrene can be prepared by following the teachings herein. Optionally, copolymers comprising ethylene, styrene and a C3-C20 alpha olefin, optionally comprising a C4-C20 diene, having improved properties can be prepared.

[0036] Suitable non-conjugated diene monomers can be a straight chain, branched chain or cyclic hydrocarbon diene having from 6 to 15 carbon atoms. Examples of suitable non-conjugated dienes include, but are not limited to, straight chain acyclic dienes, such as 1,4-hexadiene, 1,6- octadiene, 1,7-octadiene, 1,9-decadiene, branched chain acyclic dienes, such as 5-methyl-l,4- hexadiene; 3,7-dimethyl-l,6-octadiene; 3, 7-dimethyl- 1,7-octadiene and mixed isomers of dihydromyricene and dihydroocinene, single ring alicyclic dienes, such as 1,3-cyclopentadiene; 1,4-cyclohexadiene; 1,5-cyclooctadiene and 1,5-cyclododecadiene, and multi-ring alicyclic fused and bridged ring dienes, such as tetrahydroindene, methyl tetrahydroindene, dicyclopentadiene,bicyclo-(2,2,l)-hepta-2,5-diene; alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes, such as 5-methylene-2-norbornene (MNB); 5-propenyl-2-norbornene, 5- isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene, 5-cyclohexylidene-2- norbornene, 5-vinyl-2-norbornene, and norbornadiene. Of the dienes typically used to prepare EPDMs, the particularly preferred dienes are 1,4-hexadiene (HD), 5-ethylidene-2-norbornene (ENB), 5-vinylidene-2-norbornene (VNB), 5-methylene-2-norbornene (MNB), and dicyclopentadiene (DCPD). The especially preferred dienes are 5-ethylidene-2-norbornene (ENB) and 1,4-hexadiene (HD).

[0037] One class of desirable polymers that can be made in accordance with embodiments of the invention are elastomeric copolymers of ethylene, a C3-C20 a-olefin, especially propylene, and optionally one or more diene monomers. Preferred a-olefins for use in this embodiment of the present invention are designated by the formula CH2=CHR*, where R* is a linear or branched alkyl group of from 1 to 12 carbon atoms. Examples of suitable a-olefins include, but are not limited to, propylene, isobutylene, 1 -butene, 1 -pentene, 1 -hexene, 4-methyl-l -pentene, and 1- octene. A particularly preferred a-olefin is propylene. The propylene based polymers are generally referred to in the art as EP or EPDM polymers. Suitable dienes for use in preparing such polymers, especially multi-block EPDM type polymers include conjugated or nonconjugated, straight or branched chain-, cyclic- or polycyclic-dienes comprising from 4 to 20 carbons. Preferred dienes include 1,4-pentadiene, 1,4-hexadiene, 5-ethylidene-2-norbornene, dicyclopentadiene, cyclohexadiene, and 5-butylidene-2-norbornene. A particularly preferred diene is 5-ethylidene-2 -norbornene.

[0038] Because the diene containing polymers comprise alternating segments or blocks containing greater or lesser quantities of the diene (including none) and a-olefin (including none), the total quantity of diene and a-olefin may be reduced without loss of subsequent polymer properties. That is, because the diene and a-olefin monomers are preferentially incorporated into one type of block of the polymer rather than uniformly or randomly throughout the polymer, they are more efficiently utilized and subsequently the crosslink density of the polymer can be better controlled. Such crosslinkable elastomers and the cured products have advantaged properties, including higher tensile strength and better elastic recovery.

[0039] The ethylene / a-olefm copolymers can be functionalized by incorporating at least one functional group in its polymer structure. Exemplary functional groups may include, for example, ethylenically unsaturated mono- and di-functional carboxylic acids, ethylenically unsaturated mono- and di-functional carboxylic acid anhydrides, salts thereof and esters thereof. Such functional groups may be grafted to an ethylene / a-olefm copolymer, or it may be copolymerized with ethylene and an optional additional comonomer to form an copolymer of ethylene, the functional comonomer and optionally other comonomer(s). Means for grafting functional groups onto polyethylene are described for example in U.S. Pat. Nos. 4,762,890, 4,927,888, and 4,950,541, the disclosures of these patents are incorporated herein by reference in their entirety. One particularly useful functional group is maleic anhydride.

[0040] The amount of the functional groups present in the functional copolymer can vary. The functional group can typically be present in a copolymer-type functionalized copolymer in an amount of at least 1.0 weight percent, preferably at least 5 weight percent, and more preferably at least 7 weight percent. The functional group will typically be present in a copolymer-type functionalized copolymer in an amount less than 40 weight percent, preferably less than 30 weight percent, and more preferably less than 25 weight percent.

[0041] An exemplary olefin block copolymer comprises ethylene and octene. A commercially available olefin block copolymer that can be used in the foam is INFUSE™ from the Dow Chemical company.

[0042] Another exemplary ethylene for as an elastomer is homogeneously branched ethylene-a- olefin copolymers. These copolymers can be made with a single-site catalyst such as a metallocene catalyst or constrained geometry catalyst, and typically have a melting point of less than 105, specifically less than 90, more specifically less than 85, even more specifically less than 80 and still more specifically less than 75°C. The melting point is measured by differential scanning calorimetry (DSC) as described, for example, in USP 5,783,638. The a-olefin is preferably a C3-20 linear, branched or cyclic a-olefin. Examples of C3-20 a-olefins include propene, 1 -butene, 4-methyl-l -pentene, 1 -hexene, 1 -octene, 1 -decene, 1 -dodecene, 1 -tetradecene, 1 -hexadecene, and 1 -octadecene. The a-olefins can also contain a cyclic structure such ascyclohexane or cyclopentane, resulting in an a-olefin such as 3 -cyclohexyl- 1 -propene (allyl cyclohexane) and vinyl cyclohexane.

[0043] Illustrative homogeneously branched ethylene-a-olefin copolymers include ethylene / propylene, ethylene / butene, ethylene / 1 -hexene, ethylene / 1 -octene, ethylene / styrene, and the like. Illustrative terpolymers include ethylene / propylene / 1 -octene, ethylene / propylene / butene, ethylene / butene / 1 -octene, and ethylene / butene / styrene. The copolymers can be random copolymers or block copolymers.

[0044] Examples of commercially available homogeneously branched ethylene-a-olefin copolymers include homogeneously branched, linear ethylene-a-olefin copolymers (e.g. TAFMER™ by Mitsui Petrochemicals Company Limited and EXACT™ by Exxon Chemical Company), and the homogeneously branched, substantially linear ethylene-a-olefin polymers (e.g., AFFINITY™ and ENGAGE™ polyethylene available from the Dow Chemical Company).

[0045] Coupling Agent

[0046] The foamable composition also comprises a coupling agent comprising a copolymer of ethylene or a functionalized polyethylene. For example, the coupling agent may be a copolymer of ethylene and maleic acid monethyl ester, a polyethylene grafted with maleic anhydride, or a combination of these. Without being limited by theory, the coupling agent compatibilizes the hydrocarbons such as polyolefin elastomer, and an olefin block copolymer (OBC) with EVA, which is a polar copolymer.

[0047] In an embodiment, the foamable composition contains a coupling agent in an amount from 0 pph to 5 pph. The coupling agent may be present in the formable composition in amount greater than or equal to 0.5 pph and less than or equal to 4 pph, greater than or equal to 1 pph and less than or equal to 3.75 pph, or even greater than or equal to 2 pph and less than or equal to 3.5 pph, and any and all sub ranges between the above ranges.

[0048] The olefin copolymer comprises an ethylene polymer that has grafted thereto (or copolymerized thereto) an unsaturated carboxylic acid or an anhydride, ester, amide, or imide, hereafter designated as “grafting compound”. The grafting compound preferably is an aliphaticunsaturated dicarboxylic add or an anhydride. The carboxylic acid preferably contains up to 4, preferably up to 5, and more preferably up to 6 carbon atoms. Examples of unsaturated carboxylic acids are maleic acid, fumaric acid, itaconic add, acrylic acid, methacrylic acid, crotonic acid, and citraconic acid. Examples of derivatives of unsaturated carboxylic acids are maleic anhydride, citraconic anhydride, itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, monomethyl itaconate, diethyl itaconate, acrylamide, methacrylamide, monomaleamide, dimaleamide, N,N- diethylmaleamide, N-monobutylmaleamide, N,N-dibutylmaleamide, monofumaramide, difumaramide, N-monoethylfumaramide, N,N-diethylfumaramide, N-monobutylfumaramide, N,N-dibutylfumaramide, maleimide, N-butylmaleimide, N-phenylmaleimide, sodium acrylate, sodium methacrylate, potassium acrylate, and potassium methacrylate.

[0049] Examples of olefin copolymer include ethylene / (meth) aery lie acid copolymers, ethylene / (meth)acrylic acid / n-butyl(meth)acrylate copolymers, ethylene / (meth)acrylic acid / iso- butyl(meth)acrylate copolymers, ethylene / (meth)acrylic acid / tert-butyl(meth)acrylate copolymers, ethylene / (meth)acrylic acid / methyl(meth)acrylate copolymers, ethylene / (meth)acrylic acid / ethyl(meth)acrylate copolymers, ethylene / maleic acid and ethylene / maleic acid monoester copolymers, ethylene / maleic acid monoester / n- butyl(meth)acrylate copolymers, ethylene / maleic acid monoester / methyl(meth)acrylate copolymers, ethylene / maleic acid monoester / ethyl(meth)acrylate copolymers, or combinations of two or more thereof.

[0050] One or more, preferably one, grafting compound is grafted onto the ethylene polymer. Maleic anhydride is the preferred grafting compound. An exemplary unsaturated carboxylic acid is acrylic acid or methacrylic acid. In an embodiment, ethylene / (meth)acrylic acid copolymers are preferred.

[0051] The graft process can be initiated by decomposing initiators to form free radicals, including azo-containing compounds, carboxylic peroxyacids and peroxyesters, alkyl hydroperoxides, and dialkyl and diacyl peroxides, among others. Many of these compounds and their properties have been described (Reference: J. Branderup, E. Immergut, E. Grulke, eds. “Polymer Handbook,” 4thecL, Wiley, New York, 1999, Section II, pp. 1-76.). Alternatively, the grafting compound can be copolymerized with ethylene by typical tubular and autoclave processes.

[0052] The grafted ethylene polymer, as well as the ethylene polymer which is used for grafting, is selected from ultralow density polyethylene (ULDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), high melt strength high density polyethylene (HMS-HDPE), ultrahigh density polyethylene (UHDPE), or combinations thereof.

[0053] In an embodiment, the grafted ethylene polymer, as well as the ethylene polymer which is used for grafting, preferably have a density of up to 0.960 g / cm3, more preferably from 0.850 to 0.950 g / cm3, most preferably from 0.860 to 0.945 g / cm3, particularly from 0.865 to 0.940 g / cm3. However, it is to be understood that the polymer density changes slightly upon grafting. In the case of ethylene polymers, it has been found that the polymer density is important for providing a primer with sufficient mechanical strength and flexibility and for achieving a sufficient solubility of the grafted ethylene polymer in the organic solvent.

[0054] In an embodiment, the grafted ethylene polymer, as well as the ethylene polymer which is used for grafting, preferably have a melt index of greater or equal to 20 g / lOmin, greater than or equal to 21 g / lOmin, greater than or equal to 22 g / lOmin, greater than or equal to 23 g / lOmin, greater than or equal to 24 g / lOmin, greater than or equal to 25 g / lOmin, greater than or equal to 26 g / lOmin, greater than or equal to 27 g / lOmin, greater than or equal to 28 g / lOmin, greater than or equal to 29 g / lOmin, or even greater than or equal to 30 g / lOmin.

[0055] Recycled Material

[0056] In embodiments, the recycled material used may originate from the waste produced during the skinning and profiling of foam blocks used for manufacturing footwear soles. The primary components of this recycled material include low-density polyethylene (EDPE), ethylene vinyl acetate (EVA), and calcium carbonate (CaC'Os). It is contemplated that other types of recycled may be used.

[0057] In an embodiment, the foamable composition contains recycled material in an amount from 40 pph to 70 pph. The recycled material may be present in the formable composition in amount greater than or equal to 40 pph and less than or equal to 70 pph, greater than or equal to 45 pph and less than or equal to 65 pph, greater than or equal to 50 pph and less than or equal to 60 pph, or even greater than or equal to 55 pph and less than or equal to 60 pph, and any and all sub ranges between the above ranges.

[0058] Cross-linking Agent

[0059] The foamable composition also contains a crosslinking agent. Crosslinking agents include one or more organic peroxides including dialkyl peroxides, peroxy esters, peroxy dicarbonates, peroxy ketals, diacyl peroxides, or combinations of two or more thereof. Examples of peroxides include dicumyl peroxide (also known as a,a’-Bis(tert-butylperoxy) diisopropylbenzene (BIPB)), di(3,3,5-trimethyl hexanoyl)peroxide, t-butyl peroxypivalate, t- butyl peroxyneodecanoate, di(sec-butyl)peroxy dicarbonate, t-amyl peroxyneodecanoate, 1,1-di-t- butyl peroxy-3,3,5-trimethylcyclohexane, t-butyl-cumyl peroxide, 2,5-dimethyl-2,5-di(tertiary- butyl-peroxyl)hexane, l,3-bis(tertiary-butyl-peroxyl-isopropyl)benzene, or a combination thereof. An exemplary crosslinking agent is dicumyl peroxide commercially available under the tradename EUPEROX® from Arkema, Peroximon® from Arkema or the tradename TRIGONOX® from Akzo Nobel.

[0060] In an embodiment, the foamable composition contains a cross-linking agent in an amount from 0.5 pph to 2 pph. The cross-linking agent may be present in the formable composition in amount greater than or equal to 0.5 pph and less than or equal to 2 pph, greater than or equal to 1 pph and less than or equal to 1.75 pph, or even greater than or equal to 1.5 pph and less than or equal to 1.75 pph, and any and all sub ranges between the above ranges.

[0061] Blowing Agent

[0062] The foamable composition may also contain a suitable blowing agent in order to generate porosity to form the foam upon heating. It is desirable to use blowing agents that decompose (to release gases) at around the same temperature that the crosslinking agent decomposes. This permits the formation of a foam with subsequent crosslinking that facilitatesthe retention of porosity in the foam. It is generally desirable to use blowing agents in an amount effective to produce a fairly uniform cell size in the foam. The blowing agent generally acts in conjunction with the curing agent to facilitate a uniform crosslink density as well as a uniform pore size in the foam. The blowing agents may be physical blowing agents or chemical blowing agents. Physical blowing agents are released from the composition as a result of binodal decomposition and expand during the blowing process to form the foam while chemical blowing agents decompose to liberate gases (e.g., azo compounds) during the blowing process to form a foam.

[0063] Physical blowing agents comprising hydrogen atom-containing components, may be used alone or as mixtures with each other or with another type of blowing agent (e.g., chemical blowing agents) such as azo compounds. The physical blowing agents may be selected from a broad range of materials, including hydrocarbons, ethers, esters and partially halogenated hydrocarbons (e.g., perfluorinated hydrocarbons), ethers and esters, and the like. The physical blowing agents may also include relatively inert gases such as nitrogen, argon, carbon dioxide, and the like. Typical physical blowing agents have a boiling point between - 50°C and 100°C, and preferably between -50°C and 50°C. Among the usable hydrogen-containing blowing agents are the HCFC's (halo chlorofluorocarbons) such as 1,1-dichloro-l-fluoroethane, l,l-dichloro-2,2,2- trifluoro-ethane, monochlorodifluoromethane, and 1 -chloro- 1,1 -difluoroethane; the HFCs (halo fluorocarbons) such as 1,1,1, 3,3, 3-hexafluoropropane, 2, 2, 4, 4- tetrafluorobutane, 1,1, 1,3 ,3 ,3- hexafluoro-2 -methylpropane, 1,1, 1,3, 3- pentafluoropropane, 1,1,1,2,2-pentafluoropropane, 1,1,1,2,3-pentafluoropropane, 1 , 1 ,2,3,3-pentafluoropropane, 1 , 1 ,2,2,3-pentafluoropropane, 1 , 1 , 1 ,3,3,4- hexafluorobutane, 1,1, 1 ,3 ,3 -pentafluorobutane, 1,1,1 ,4,4,4-hexafluorobutane, 1,1,1 ,4,4-pentafluorobutane, 1 ,1 ,2, 2, 3, 3-hexafluoropropane, 1 ,1 ,1 ,2,3,3- hexafluoropropane, 1,1 -difluoroethane, 1,1,1,2-tetrafluoroethane, and pentafluoroethane; the HFE ' s (halo fluoroethers) such as methyl- 1,1,1- trifluoroethyl ether and difluoromethyl-l,l,l-trifluoroethyl ether; and the hydrocarbons such as n-pentane, isopentane, cyclopentane, or the like.

[0064] Gaseous non-CFC or non-HCFC physical blowing agents such as carbon dioxide, nitrogen, dinitroso-pentamethylene-tetramine, SFe, nitrous oxide, argon, helium, noble gases, such as xenon, air (nitrogen and oxygen blend), and blends of these gases. The gases may be used as blowing agents in the gaseous state, a liquid state or in a supercritical state.

[0065] Chemical blowing agents include azobisisobutyronitrile (AIBN), azodicarbonamide, dinitroso-pentamethylene -tetramine, p-toluene sulfonyl hydrazide, p,p'-oxy-bis(benzenesulfonyl hydrazide), or combinations thereof may be used to produce the foam. An exemplary azo compound is azobisisobutyronitrile. In order to tailor expansion-decomposition temperature and foaming processes, a blowing agent may also be a mixture of blowing agents or of blowing agents and an activator.

[0066] The blowing agent is used in an amount of 0.1 to 10 pph, preferably 1 to 5 pph and more preferably 2 to 4 pph, based on the total weight of the foamable composition.

[0067] Catalyst

[0068] The foamable composition may also include 0.1 to 10 pph, preferably 0.2 to 5 pph, and more preferably 0.3 to 4 pph of a catalyst to lower the decomposition temperature / profde of blowing agents. A catalyst can be one or more metal oxides, metal salts, metal hydroxides or organometallic complexes, or a combination thereof. Examples of catalysts are zinc oxide, zinc stearate, magnesium hydroxide, calcium carbonate, or the like, or a combination thereof. The catalyst may facilitate the neutralization of the carboxylic acid during the reaction to produce the foam. This may improve the compressive strength of the foam.

[0069] Additives

[0070] Other additives, which can be present in the composition from 0.1 to 20 or 2 to 12 wt% based on the total weight of the composition, may include, pigment (TiO2 and other compatible colored pigments), adhesion promoter (to improve adhesion of the expanded foam to other materials), fdler (e.g., calcium carbonate, barium sulfate, and / or silicon oxide), nucleating agent (pure form or concentrate form, e.g., CaCC , SiCh, or combinations of two or more thereof, rubber (to improve rubber-like elasticity, such as natural rubber, SBR, poly butadiene, and / or ethylene propylene diene terpolymer), stabilizer (e.g., antioxidants, UV absorbers, and / or flame retardants), and processing aids (e.g., Octene R-130 manufactured by Octene Co., Taiwan). Antioxidant (modifying the organoleptic properties such as reducing odor or taste) can include phenolic antioxidants such as IRGANOX from Ciba Geigy Inc. (Tarrytown, N.Y.).

[0071] Foamable Composition

[0072] In embodiments, the foamable composition may have an expansion ratio greater than or equal to 180% and less than or equal to 200%, greater than or equal to 182% and less than or equal to 198%, greater than or equal to 184 and less than or equal to 196%, greater than or equal to 186% and less than or equal to 194%, greater than or equal to 188% and less than or equal to 192%, greater than or equal to 190% and less than or equal to 192%, and any and all sub ranges between the above ranges. Without being bound by theory, it is believed that the expansion ratio may be adjusted by changing the amount of foaming agent, the processing conditions or the type of EVA utilized in the composition.

[0073] In embodiments, the foamable composition may have an Asker C hardness greater than or equal to 40 and less than or equal to 60, greater than or equal to 42 and less than or equal to 58, greater than or equal to 44 and less than or equal to 56, greater than or equal to 46 and less than or equal to 54, greater than or equal to 48 and less than or equal to 52, greater than or equal to 50 and less than or equal to 52, and any and all sub ranges between the above ranges. Without being bound by theory, it is believed that the Asker C hardness may be adjusted by changing the polyolefin elastomer or EVA, or by adding olefin block copolymer.

[0074] Rebound indicates how much bounce a shoe can provide when running or jumping. A typical 100% EVA formulation has a 44% rebound. In embodiments, the foamable composition may have a rebound greater than or equal to 40% and less than or equal to 55%, greater than or equal to 42% and less than or equal to 53%, greater than or equal to 44% and less than or equal to 51%, greater than or equal to 46% and less than or equal to 49%, greater than or equal to 48% and less than or equal to 49%, and any and all sub ranges between the above ranges. Without being bound by theory, it is believed that the rebound may be adjusted by adding olefin block polymer, including more polyolefin elastomer and EVA, increasing the expansion ratio, or increasing curing levels.

[0075] Compression set is a property that indicates how much a foam material will deform under a given load, temperature, and duration. This property is important for footwear applications, as it directly influences the cushioning and comfort of the shoes. In embodiments, the foamable composition may have a compression set greater than or equal to 65% and less thanor equal to 75%, greater than or equal to 68% and less than or equal to 72%, greater than or equal to 70% and less than or equal to 71%, and any and all sub ranges between the above ranges.

[0076] Shrinkage is an indicator of dimensional stability in footwear foams, and lower shrinkage values imply better stability. Different customers or brands may have distinct standards for dimensional stability, with some of the more demanding ones requiring shrinkage levels between 2 and 3%. In embodiments, the shrinkage of the foamable composition may be greater than or equal to 2% and less than or equal to 3%, greater than or equal to 2.2% and less than or equal to 2.9%, greater than or equal to 2.4% and less than or equal to 2.7%, greater than or equal to 2.6% and less than or equal to 2.7%, and any and all sub ranges between the above ranges.

[0077] Tensile strength is the foam’s ability to resist deformation while being stretched. In embodiments, the foamable composition may have a tensile strength greater than or equal to 1.3% and less than or equal to 1.5%.

[0078] Processing

[0079] The foam may be produced by a number of processes, such as compression molding, injection molding, or combinations of extrusion and molding. The foamable composition may be manufactured by blending together the elastomer, the carboxylated olefin copolymer, the crosslinking agent, the blowing agent, and any other desired additives. The blending may be conducted in an extruder or internal mixer, or alternatively, the ingredients may be pre-blended in a dry blender prior to being extruded in the extruder or mixed in the internal mixer.

[0080] In one embodiment, manufacturing the foam can comprise mixing the elastomers, the carboxylated olefin copolymers, the blowing agent and the crosslinking agents under heat to form a melt. This may be conducted in a Banbury, intensive mixers, two-roll mill, or in an extruder. Time, temperature, shear rate may be regulated to ensure optimum dispersion without premature crosslinking or foaming. A high temperature of mixing may result in premature crosslinking and foaming by decomposition of peroxides and blowing agents. An adequate temperature may be desired to insure good mixing of and dispersion of other ingredients. The upper temperature limit for safe operation may depend on the onset decomposition temperatures of peroxides and blowing agents employed. The ingredients can form a uniform mixture when blended at temperatures of60°C to 150°C, preferably 70°C to 140°C, and more preferably 80°C to 130°C, and even more preferably 90°C to 120°C. The polymers may be melt-blended before compounded with other ingredient(s).

[0081] After mixing, shaping can be carried out. Sheeting rolls or calendar rolls are often used to make appropriately dimensioned sheets for foaming. An extruder may be used to shape the composition into pellets.

[0082] Foaming can be carried out in a compression or injection mold at a temperature and time to complete the decomposition of peroxides and blowing agents. Pressures, molding temperature, and heating time may be controlled. Foaming can be carried out in an injection molding equipment by using foamable composition in pellet form. The resulting foam can be further shaped to the dimension of finished products by any means known in the art such as by thermoforming and compression molding.

[0083] Test Methods

[0084] The test methods as used herein include the following:

[0085] Expansion Ratio

[0086] Expansion ratio of the foam is calculated using the following formula: ((final length) - (initial length)) / (initial length).

[0087] Asker C Hardness

[0088] The Asker C hardness test was conducted according to ASTM D2240. The hardness was an average of five readings (5 seconds latency) measured across the surface of the sample and measured again after aging 40 minutes at both 70 °C and 100 °C.

[0089] Rebound

[0090] The rebound of the foam samples were measured according to DIN 53512 / ASTM D1721.

[0091] Foam Density

[0092] Foam density was calculated according to ASTM D792.

[0093] Compression Set

[0094] Compression Set (C-Set) was measured per ASTM D395 method B under conditions of 50% compression at 50 °C for 6 hours. Two buttons were tested per foam and the average reported. The compression set was calculated by using the following equation:Compression set= (TI-T2) / (TI-TQ)* 100% where To is the interval distance of the apparatus, Ti is the sample thickness before test and T2 is the sample thickness after test.

[0095] Shrinkage

[0096] Foam samples were cut using the vertical band saw. The foam was measured for width Wi and length Li, placed in a pre-heated oven between 70 to 100 °C, and removed after 40 minutes. Samples width WF and length FF were re -measured after 30 minutes of cooling at room temperature. The following formula is used to calculate the shrinkage of foam sampleA = (1-(WF+ LF) / (WI+ LI))* 100.

[0097] Tensile Strength, Elongation, and 100% Modulus

[0098] Tensile strength, elongation, and 100% modulus were measured according to ASTM D638.

[0099] Type C Tear and Split Tear Resistance

[0100] The Type C tear and split tear strength was measured by using a specimen with the dimension of 6” (length) * 1” (width) * 0.4” (thickness) and the notch depth of 1-1.5” at the testing speed of 2 inches / minute according to ASTM D3574.EXAMPLES

[0101] 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.

[0102] The materials used in this study are shown in Table 1.

[0103] Table 1 - Reagents

[0104] All ingredients were incorporated using first high shear banbury blender until the temperature reached 220 °C. At 220 °C, the blend was discharged and placed in the roll mixer until obtaining a smooth dough that then was laminated. The sheets were piled and them in a compression mold between 190 and 200 °C for 5 minutes. Once the time is up, the mold opens and lets the foam expand freely.

[0105] Table 2: Example Compositions

[0106] The PIR comprised a combination of ethylene vinyl acetate (EVA), CaCOs and some amount of polyolefin elastomer (POE).

[0107] Table 3: Example Properties

[0108] As seen above in Table 3, the results revealed that, although the difference was small, the more PIR the foam contained, the less it deformed, as evidenced by the compression set and hardness. The results show that the use of relatively high amounts of recycled material (e.g., greater than or equal to 40 pph) will not significantly impact the compression set of the final product. As mentioned herein, utilizing an EVA with a melt index of at least 15 g / lOmin as a baseresin helps counteract the reduction in flow caused by the high amount of recycled material, thereby facilitating better processing and handling of the dough while maintaining acceptable performance properties in the final foam product.

[0109] Additionally, increasing the amount of recycled material enhances the dimensional stability of the foams, aligning with the expectations of high-quality brands. Additionally, adding OBC to the base polymer mix can further improve other properties of the recycled materialcontaining formulas while maintaining low shrinkage.

[0110] Increasing the amount of recycled material also does not harm and may even slightly enhance the foam's tensile strength, making it comparable to high-quality foams.

[0111] The subject matter 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 feature is 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.

[0112] 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.”

[0113] 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 %).

[0114] 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. A foam formed from a composition, wherein the composition comprises: from 25 pph to 55 pph, based on the composition, of ethylene vinyl acetate copolymer (EVA), wherein the EVA has a melt index of at least 15 dg / min; from 5 pph to 15 pph, based on the composition, of a polyolefin elastomer, an olefin block copolymer, or combinations of these; from 2 pph to 10 pph, based on the composition, of a coupling agent, wherein the coupling agent comprises ethylene-based polymer; and from at least 40 pph to 70 pph, based on the composition, of recycled material.

2. The foam of claim 1, wherein the recycled material comprises post-industrial recycled material (PIR), post-consumer recycled material (PCR), or combinations thereof.

3. The foam of any preceding claim, wherein the recycled material comprises PIR, the PIR having one or more of low-density polyethylene, ethylene vinyl acetate, and calcium carbonate4. The foam of any preceding claim, wherein the coupling agent comprises at least one of: a copolymer of ethylene and maleic acid monoethyl ester; or an polyethylene grafted with maleic anhydride.

5. The foam of any preceding claim, wherein the composition comprises:50 pph to 70 pph, based on the composition, of recycled material;30 pph to 50 pph, based on the composition, of the EVA; and3 pph to 5 pph, based on the composition, of the coupling agent.

6. The foam of any preceding claim, wherein the polyolefin elastomer is an ethylene-octene copolymer.

7. The foam of any preceding claim, further comprising: a crosslinking agent; a blowing agent; and a catalyst.

8. The foam of claim 7, wherein the crosslinking agent comprises peroxide, the blowing agent comprises azodicarbonamide, and the catalyst comprises zinc oxide.

9. The foam of any preceding claim, wherein the foam comprises from 0.5 pph to 5 pph fdler.

10. The foam of any preceding claim, wherein the EVA has a melt index of at least 18 dg / min.

11. The foam of any preceding claim, wherein the coupling agent has a melt index of at least 20 dg / min.

12. The foam of any preceding claim, wherein the foam has at least one of: a density of 0.10 g / cc to 0.15 g / cc; an Asker C hardness of 40 to 60 when measured as per ASTM D2240; and a tensile strength of greater than 1.3 when measured as per ASTM D3574.

13. The foam of any preceding claim, wherein the foam is a crosslinked, closed cell foam.

14. An article comprising the foam of any preceding claim.

15. A method of making the foam of any of claims 1-13, the method comprising: foaming the composition in the presence of catalyst, blowing agent, and crosslinking agent to form the foam.

Images